1
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Mei R, Lin ML, Wu H, Chen LS, Shi YM, Wei Z, Tan PH. Interlayer bond polarizability model for interlayer phonons in van der Waals heterostructures. Nanoscale 2024; 16:4004-4013. [PMID: 38328885 DOI: 10.1039/d3nr06437a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Raman scattering provides essential insights into phonons, electronic structures and electron-phonon coupling within solids through the intensity of Raman peaks, which cannot be easily quantified using the classical bond polarizability model. The interlayer bond polarizability model (IBPM) had been developed to understand the Raman intensity of layer-breathing modes (LBMs) in two-dimensional materials. However, the quantitative understanding of the LBM intensity of a van der Waals heterostructure (vdWH) remains challenging. Here, in polynary vdWHs comprising twisted multilayer graphene (tMLG), MoS2 and hBN, we observed a series of LBMs, whose intensity is markedly dependent on the excitation energy and twist angle of the tMLG constituent. An improved IBPM is proposed to quantitatively understand the Raman intensity of LBMs in the tMLG-based vdWHs, including the emergence or absence of a specific LBM when the excitation energy is resonant with the electronic states of tMLG or MoS2 constituents. This work underscores the significant potential of the improved IBPM in accurately understanding and predicting the intensity profile of LBM in polynary vdWHs, even for the case of Raman scattering with excitation energies selectively resonant with the electronic states of the corresponding specific constituents.
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Affiliation(s)
- Rui Mei
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
| | - Heng Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lin-Shang Chen
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
| | - Yan-Meng Shi
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
| | - Zhongming Wei
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Fu Q, Cong X, Xu X, Zhu S, Zhao X, Liu S, Yao B, Xu M, Deng Y, Zhu C, Wang X, Kang L, Zeng Q, Lin ML, Wang X, Tang B, Yang J, Dong Z, Liu F, Xiong Q, Zhou J, Wang Q, Li X, Tan PH, Tay BK, Liu Z. Berry Curvature Dipole Induced Giant Mid-Infrared Second-Harmonic Generation in 2D Weyl Semiconductor. Adv Mater 2023; 35:e2306330. [PMID: 37737448 DOI: 10.1002/adma.202306330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 09/05/2023] [Indexed: 09/23/2023]
Abstract
Due to its inversion-broken triple helix structure and the nature of Weyl semiconductor, 2D Tellurene (2D Te) is promising to possess a strong nonlinear optical response in the infrared region, which is rarely reported in 2D materials. Here, a giant nonlinear infrared response induced by large Berry curvature dipole (BCD) is demonstrated in the Weyl semiconductor 2D Te. Ultrahigh second-harmonic generation response is acquired from 2D Te with a large second-order nonlinear optical susceptibility (χ(2) ), which is up to 23.3 times higher than that of monolayer MoS2 in the range of 700-1500 nm. Notably, distinct from other 2D nonlinear semiconductors, χ(2) of 2D Te increases extraordinarily with increasing wavelength and reaches up to 5.58 nm V-1 at ≈2300 nm, which is the best infrared performance among the reported 2D nonlinear materials. Large χ(2) of 2D Te also enables the high-intensity sum-frequency generation with an ultralow continuous-wave (CW) pump power. Theoretical calculations reveal that the exceptional performance is attributed to the presence of large BCD located at the Weyl points of 2D Te. These results unravel a new linkage between Weyl semiconductor and strong optical nonlinear responses, rendering 2D Te a competitive candidate for highly efficient nonlinear 2D semiconductors in the infrared region.
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Affiliation(s)
- Qundong Fu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- IRL 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Singapore, 637553, Singapore
| | - Xin Cong
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China
| | - Xiaodong Xu
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China
| | - Song Zhu
- School of Electrical & Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Xiaoxu Zhao
- School of Materials Science and Engineering, Peking University, Beijing, 100871, P. R. China
| | - Sheng Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Bingqing Yao
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Manzhang Xu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Ya Deng
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Chao Zhu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Xiaowei Wang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Lixing Kang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Qingsheng Zeng
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China
| | - Xingli Wang
- IRL 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Singapore, 637553, Singapore
| | - Bijun Tang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Jianqun Yang
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China
| | - Zhili Dong
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Fucai Liu
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Qihua Xiong
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, P. R. China
| | - Jiadong Zhou
- Key Lab of advanced optoelectronic quantum architecture and measurement (Ministry of Education), Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems, and School of Physics, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Qijie Wang
- IRL 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Singapore, 637553, Singapore
- School of Electrical & Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Xingji Li
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China
| | - Beng Kang Tay
- IRL 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Singapore, 637553, Singapore
| | - Zheng Liu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- IRL 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Singapore, 637553, Singapore
- Institute for Functional Intelligent Materials, National University of Singapore, Blk S9, Level 9, 4 Science Drive 2, Singapore, 117544, Singapore
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3
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Kutkan S, Dhanabalan B, Lin ML, Tan PH, Schleusener A, Arciniegas MP, Krahne R. Impact of the organic cation on the band-edge emission of two-dimensional lead-bromide perovskites. Nanoscale 2023; 15:12880-12888. [PMID: 37477377 DOI: 10.1039/d3nr02172f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Organic-inorganic low-dimensional layered metal-halide perovskites are semiconductors in which the optoelectronic properties can be tuned by the material composition and the design of the layered architecture. While the electronic band structure is mainly determined by the inorganic octahedra lattice, the binding and conformation of the organic cations induces related lattice distortions that can break the symmetry and lead to the splitting of the exciton energy levels, and influence the dielectric confinement. Furthermore, organic-induced lattice deformations lead to offsets in k-space (where k is the wavevector) that go along with the exciton energy level splitting. Hence, the electronic transitions between these levels require the momentum contribution of phonons, and contributions of phonons in the exciton recombination dynamics result in thermal broadening of the emission linewidth. In this work, we investigate the band-edge emission of two-dimensional Ruddlesden-Popper lead-bromide perovskites synthesized with different organic cations that vary in their binding head group and their alkyl chain length. We find several peaks in the low-temperature photoluminescence spectra, and the number of peaks in the band-edge emission and their decay dynamics depend strongly on the type of organic cation in the material, which we relate to the difference in the inorganic lattice distortions that the cations induce. For two-dimensional layered perovskites with mainly in-plane distortions, induced by short primary ammonium molecules, we find a two-fold splitting of the band edge emission at low temperatures. If also out-of-plane distortions are present, as for the long-chain primary ammoniums, a three-fold splitting is observed. Interestingly, the low-energy peaks of the split series merge into the highest energy peak with increasing temperature. Thermal broadening analysis of the temperature-dependent photoluminescence linewidth in the structures with out-of-plane distortions yields energies that are larger than those reported for the inorganic lattice phonons. This indicates the involvement of either high-frequency oscillations involving the organic cations, or the broadening might be related to higher order phonon scattering processes in the excitonic recombination process. The strong directionality of the phonon modes in the octahedral lattice could promote the involvement of multiple electron-phonon scattering processes in the exciton relaxation dynamics, for example involving modes with orthogonal directionality.
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Affiliation(s)
- Seda Kutkan
- Italian Institute of Technology (IIT), Via Morego 30, 16163 Genoa, Italy.
| | - Balaji Dhanabalan
- Italian Institute of Technology (IIT), Via Morego 30, 16163 Genoa, Italy.
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
| | | | | | - Roman Krahne
- Italian Institute of Technology (IIT), Via Morego 30, 16163 Genoa, Italy.
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4
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Wu H, Lin ML, Zhou Y, Zhang X, Tan PH. Analyzing Fundamental Properties of Two-Dimensional Materials by Raman Spectroscopy from Microscale to Nanoscale. Anal Chem 2023. [PMID: 37427912 DOI: 10.1021/acs.analchem.3c00272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Affiliation(s)
- Heng Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Yan Zhou
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xin Zhang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
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5
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Hao H, Lin ML, Xu B, Wu H, Wang Y, Peng H, Tan PH, Tong L, Zhang J. Enhanced Layer-Breathing Modes in van der Waals Heterostructures Based on Twisted Bilayer Graphene. ACS Nano 2023. [PMID: 37267416 DOI: 10.1021/acsnano.3c00022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The characterization of interlayer coupling in two-dimensional van der Waals heterostructures (vdWHs) is essential to understand their quantum behaviors and structural functionalities. Interlayer shear and layer-breathing (LB) phonons carry rich information on interlayer interaction, but they are usually too weak to be detected via standard Raman spectroscopy due to the weak electron-phonon coupling (EPC). Here, we report a universal strategy to enhance LB modes of vdWHs based on twisted bilayer graphene (tBLG). In both tBLG/hBN and tBLG/MoS2 vdWHs, the resonantly excited electrons in tBLG can strongly couple to LB phonons extended over the entire layers in the vdWHs, whose resonance condition is tunable by the twist angle of tBLG. In vdWHs containing twisted graphene layers with multiple twisted interfaces, the EPC of LB phonons coming from the collective LB vibrations of entire heterostructure layers can be tuned by resonant excitation of programmable van Hove singularities according to each twisted interface. The universality and tunability of enhanced LB phonons by tBLG make it a promising method to investigate EPC and interlayer interaction in related vdWHs.
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Affiliation(s)
- He Hao
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
| | - Bo Xu
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Heng Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
| | - Yuechen Wang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Hailin Peng
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
| | - Lianming Tong
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Jin Zhang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
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6
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Sun Y, Yin S, Peng R, Liang J, Cong X, Li Y, Li C, Wang B, Lin ML, Tan PH, Wan C, Liu K. Abnormal Out-of-Plane Vibrational Raman Mode in Electrochemically Intercalated Multilayer MoS 2. Nano Lett 2023. [PMID: 37219946 DOI: 10.1021/acs.nanolett.3c01543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Raman spectroscopy is a powerful technique to probe structural and doping behaviors of two-dimensional (2D) materials. In MoS2, the always coexisting in-plane (E2g1) and out-of-plane (A1g) vibrational modes are used as reliable fingerprints to distinguish the number of layers, strains, and doping levels. In this work, however, we report an abnormal Raman behavior, i.e., the absence of the A1g mode in cetyltrimethylammonium bromide (CTAB)-intercalated MoS2 superlattice. This unusual behavior is quite different from the softening of the A1g mode induced by surface engineering or electric-field gating. Interestingly, under a strong laser illumination, heating, or mechanical indentation, an A1g peak gradually appears, accompanied by the migration of intercalated CTA+ cations. The abnormal Raman behavior is mainly attributed to the constraint of the out-of-plane vibration due to intercalations and resulting severe electron doping. Our work renews the understanding of Raman spectra of 2D semiconducting materials and sheds light on developing next-generation devices with tunable structures.
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Affiliation(s)
- Yufei Sun
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Shujia Yin
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Ruixuan Peng
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Jia Liang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Xin Cong
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Yi Li
- College of Mathematics and Physics, Beijing University of Chemical Technology, Beijing 100029, China
| | - Chenyu Li
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Bolun Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Chunlei Wan
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Kai Liu
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
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7
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Chen X, Reichardt S, Lin ML, Leng YC, Lu Y, Wu H, Mei R, Wirtz L, Zhang X, Ferrari AC, Tan PH. Control of Raman Scattering Quantum Interference Pathways in Graphene. ACS Nano 2023; 17:5956-5962. [PMID: 36897053 PMCID: PMC10062028 DOI: 10.1021/acsnano.3c00180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Graphene is an ideal platform to study the coherence of quantum interference pathways by tuning doping or laser excitation energy. The latter produces a Raman excitation profile that provides direct insight into the lifetimes of intermediate electronic excitations and, therefore, on quantum interference, which has so far remained elusive. Here, we control the Raman scattering pathways by tuning the laser excitation energy in graphene doped up to 1.05 eV. The Raman excitation profile of the G mode indicates its position and full width at half-maximum are linearly dependent on doping. Doping-enhanced electron-electron interactions dominate the lifetimes of Raman scattering pathways and reduce Raman interference. This will provide guidance for engineering quantum pathways for doped graphene, nanotubes, and topological insulators.
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Affiliation(s)
- Xue Chen
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center
of Materials Science and Optoelectronics Engineering and CAS Center
of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sven Reichardt
- Department
of Physics and Materials Science, University
of Luxembourg, Luxembourg 1511, Luxembourg
| | - Miao-Ling Lin
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Yu-Chen Leng
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Yan Lu
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Heng Wu
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center
of Materials Science and Optoelectronics Engineering and CAS Center
of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rui Mei
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center
of Materials Science and Optoelectronics Engineering and CAS Center
of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ludger Wirtz
- Department
of Physics and Materials Science, University
of Luxembourg, Luxembourg 1511, Luxembourg
| | - Xin Zhang
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center
of Materials Science and Optoelectronics Engineering and CAS Center
of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Andrea C. Ferrari
- Cambridge
Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Ping-Heng Tan
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center
of Materials Science and Optoelectronics Engineering and CAS Center
of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
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8
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Pan F, Ni K, Xu T, Chen H, Wang Y, Gong K, Liu C, Li X, Lin ML, Li S, Wang X, Yan W, Yin W, Tan PH, Sun L, Yu D, Ruoff RS, Zhu Y. Long-range ordered porous carbons produced from C 60. Nature 2023; 614:95-101. [PMID: 36631612 DOI: 10.1038/s41586-022-05532-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/04/2022] [Indexed: 01/13/2023]
Abstract
Carbon structures with covalent bonds connecting C60 molecules have been reported1-3, but their production methods typically result in very small amounts of sample, which restrict the detailed characterization and exploration necessary for potential applications. We report the gram-scale preparation of a new type of carbon, long-range ordered porous carbon (LOPC), from C60 powder catalysed by α-Li3N at ambient pressure. LOPC consists of connected broken C60 cages that maintain long-range periodicity, and has been characterized by X-ray diffraction, Raman spectroscopy, magic-angle spinning solid-state nuclear magnetic resonance spectroscopy, aberration-corrected transmission electron microscopy and neutron scattering. Numerical simulations based on a neural network show that LOPC is a metastable structure produced during the transformation from fullerene-type to graphene-type carbons. At a lower temperature, shorter annealing time or by using less α-Li3N, a well-known polymerized C60 crystal forms owing to the electron transfer from α-Li3N to C60. The carbon K-edge near-edge X-ray absorption fine structure shows a higher degree of delocalization of electrons in LOPC than in C60(s). The electrical conductivity is 1.17 × 10-2 S cm-1 at room temperature, and conduction at T < 30 K appears to result from a combination of metallic-like transport over short distances punctuated by carrier hopping. The preparation of LOPC enables the discovery of other crystalline carbons starting from C60(s).
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Affiliation(s)
- Fei Pan
- Department of Materials Science and Engineering, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, China
| | - Kun Ni
- Department of Materials Science and Engineering, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, China
| | - Tao Xu
- SEU-FEI Nano-Pico Center and Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing, China
| | - Huaican Chen
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China.,Spallation Neutron Source Science Center, Dongguan, China
| | - Yusong Wang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
| | - Ke Gong
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
| | - Cai Liu
- International Quantum Academy, Shenzhen, China.,Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Xin Li
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
| | - Shengyuan Li
- Department of Materials Science and Engineering, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, China
| | - Xia Wang
- Department of Materials Science and Engineering, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, China
| | - Wensheng Yan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China
| | - Wen Yin
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China.,Spallation Neutron Source Science Center, Dongguan, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
| | - Litao Sun
- SEU-FEI Nano-Pico Center and Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing, China
| | - Dapeng Yu
- International Quantum Academy, Shenzhen, China.,Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China.,Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Rodney S Ruoff
- Center for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan, Republic of Korea. .,Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea. .,Department of Materials Science and Engineering, UNIST, Ulsan, Republic of Korea. .,School of Energy and Chemical Engineering, UNIST, Ulsan, Republic of Korea.
| | - Yanwu Zhu
- Department of Materials Science and Engineering, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, China. .,Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China.
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9
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Xi Y, Jing X, Xu Z, Liu N, Liu Y, Lin ML, Yang M, Sun Y, Zhuang J, Xu X, Hao W, Li Y, Li X, Wei X, Tan PH, Li Q, Liu B, Dou SX, Du Y. Superconductivity in Layered van der Waals Hydrogenated Germanene at High Pressure. J Am Chem Soc 2022; 144:18887-18895. [PMID: 36194558 DOI: 10.1021/jacs.2c05683] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The emergence of superconductivity in two-dimensional (2D) materials has attracted tremendous research efforts because the origins and mechanisms behind the unexpected and fascinating superconducting phenomena remain unclear. In particular, the superconductivity can survive in 2D systems even with weakened disorder and broken spatial inversion symmetry. Here, structural and superconducting transitions of 2D van der Waals (vdW) hydrogenated germanene (GeH) are observed under compression and decompression processes. GeH possesses a superconducting transition with a critical temperature (Tc) of 5.41 K at 8.39 GPa. A crystalline to amorphous transition occurs at 16.80 GPa, while superconductivity remains. An abnormal increase of Tc up to 6.11 K was observed during the decompression process, while the GeH remained in the 2D amorphous phase. A combination study of in situ high-pressure synchrotron X-ray diffraction, in situ high-pressure Raman spectroscopy, transition electron microscopy, and density functional theory simulations suggests that the superconductivity in 2D vdW GeH is attributed to the increased density of states at the Fermi level as well as the enhanced electron-phonon coupling effect under high pressure even in the form of an amorphous phase. The unique pressure-induced phase transition of GeH from 2D crystalline to 2D amorphous metal hydride provides a promising platform to study the mechanisms of amorphous hydride superconductivity.
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Affiliation(s)
- Yilian Xi
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing100191, China
| | - Xiaoling Jing
- State Key Laboratory of Superhard Materials, Jilin University, Changchun130012, China
| | - Zhongfei Xu
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,College of Environmental Science and Engineering, North China Electric Power University, Beijing102206, China
| | - Nana Liu
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Yani Liu
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing100083, China
| | - Ming Yang
- School of Physics, Beihang University, Beijing100191, China
| | - Ying Sun
- School of Physics, Beihang University, Beijing100191, China
| | - Jincheng Zhuang
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Xun Xu
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Weichang Hao
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing100191, China
| | - Yanchun Li
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing100049, China
| | - Xiaodong Li
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing100049, China
| | - Xiangjun Wei
- Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing100083, China
| | - Quanjun Li
- State Key Laboratory of Superhard Materials, Jilin University, Changchun130012, China
| | - Bingbing Liu
- State Key Laboratory of Superhard Materials, Jilin University, Changchun130012, China
| | - Shi Xue Dou
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing100191, China
| | - Yi Du
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing100191, China
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10
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Lin ML, Feng M, Wu JB, Ran FR, Chen T, Luo WX, Wu H, Han WP, Zhang X, Liu XL, Xu Y, Li H, Wang YF, Tan PH. Intralayer Phonons in Multilayer Graphene Moiré Superlattices. Research (Wash D C) 2022; 2022:9819373. [PMID: 35707049 PMCID: PMC9175117 DOI: 10.34133/2022/9819373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/08/2022] [Indexed: 11/16/2022] Open
Abstract
Moiré pattern in twisted multilayers (tMLs) induces many emergent phenomena by subtle variation of atomic registry to modulate quasiparticles and their interactions, such as superconductivity, moiré excitons, and moiré phonons. The periodic superlattice potential introduced by moiré pattern also underlies patterned interlayer coupling at the interface of tMLs. Although this arising patterned interfacial coupling is much weaker than in-plane atomic interactions, it is crucial in moiré systems, as captured by the renormalized interlayer phonons in twisted bilayer transitional metal dichalcogenides. Here, we determine the quantitative relationship between the lattice dynamics of intralayer out-of-plane optical (ZO) phonons and patterned interfacial coupling in multilayer graphene moiré superlattices (MLG-MS) by the proposed perturbation model, which is previously challenging for MLGs due to their out-of-phase displacements of adjacent atoms in one atomic plane. We unveil that patterned interfacial coupling introduces profound modulations on Davydov components of nonfolded ZO phonon that are localized within the AB-stacked constituents, while the coupling results in layer-extended vibrations with symmetry of moiré pattern for moiré ZO phonons. Our work brings further degrees of freedom to engineer moiré physics according to the modulations imprinted on the phonon frequency and wavefunction.
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Affiliation(s)
- Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Feng
- School of Physics, Nankai University, Tianjin 300071, China
| | - Jiang-Bin Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Fei-Rong Ran
- Key Laboratory of Flexible Electronics and Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Tao Chen
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Wei-Xia Luo
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Heng Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wen-Peng Han
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xin Zhang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xue-Lu Liu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Yang Xu
- School of Micro-nanoelectronics, State Key Laboratory of Silicon Materials, Hangzhou Global Scientific and Technological Innovation Center, ZJU-UIUC Joint Institute, Zhejiang University, Hangzhou 310027, China
| | - Hai Li
- Key Laboratory of Flexible Electronics and Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Yu-Fang Wang
- School of Physics, Nankai University, Tianjin 300071, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
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11
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Wu J, Yao Y, Lin ML, Rösner M, Du Z, Watanabe K, Taniguchi T, Tan PH, Haas S, Wang H. Spin-Phonon Coupling in Ferromagnetic Monolayer Chromium Tribromide. Adv Mater 2022; 34:e2108506. [PMID: 35285556 DOI: 10.1002/adma.202108506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Novel 2D magnets exhibit intrinsic electrically tunable magnetism down to the monolayer limit, which has significant value for nonvolatile memory and emerging computing device applications. In these compounds, spin-phonon coupling (SPC) typically plays a crucial role in magnetic fluctuations, magnon dissipation, and ultimately establishing long-range ferromagnetic order. However, a systematic understanding of SPC in 2D magnets that combines theory and experiment is still lacking. In this work, monolayer chromium tribromide is studied to investigate SPC in 2D magnets via Raman spectroscopy and first principle calculations. The experimental Curie temperature and phonon shifts are found to be in good agreement with the numerical simulations. Specifically, it is demonstrated how magnetic exchange interactions affect phonon vibrations, which helps establish design fundamentals for 2D magnetic materials and other related devices.
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Affiliation(s)
- Jiangbin Wu
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Yu Yao
- Department of Physics & Astronomy, University of Southern California, Los Angeles, CA, 90089, USA
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Malte Rösner
- Theory of Condensed Matter Department, Radboud University, 6500 GL, Nijmegen, 29777, Netherlands
| | - Zhonghao Du
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Stephan Haas
- Department of Physics & Astronomy, University of Southern California, Los Angeles, CA, 90089, USA
| | - Han Wang
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Mork Family Department of Chemical Engineering and Material Science, University of Southern California, Los Angeles, CA, 90089, USA
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12
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Lin ML, Dhanabalan B, Biffi G, Leng YC, Kutkan S, Arciniegas MP, Tan PH, Krahne R. Correlating Symmetries of Low-Frequency Vibrations and Self-Trapped Excitons in Layered Perovskites for Light Emission with Different Colors. Small 2022; 18:e2106759. [PMID: 35218284 DOI: 10.1002/smll.202106759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/15/2022] [Indexed: 06/14/2023]
Abstract
The soft hybrid organic-inorganic structure of two-dimensional layered perovskites (2DLPs) enables broadband emission at room temperature from a single material, which makes 2DLPs promising sources for solid-state white lighting, yet with low efficiency. The underlying photophysics involves self-trapping of excitons favored by distortions of the inorganic lattice and coupling to phonons, where the mechanism is still under debate. 2DLPs with different organic moieties and emission ranging from self-trapped exciton (STE)-dominated white light to blue band-edge photoluminescence are investigated. Detailed insights into the directional symmetries of phonon modes are gained using angle-resolved polarized Raman spectroscopy and are correlated to the temperature-dependence of the STE emission. It is demonstrated that weak STE bands at low-temperature are linked to in-plane phonons, and efficient room-temperature STE emission to more complex coupling to several phonon modes with out-of-plane components. Thereby, a unique view is provided into the lattice deformations and recombination dynamics that are key to designing more efficient materials.
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Affiliation(s)
- Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Balaji Dhanabalan
- Optoelectronics Research Line, Istituto Italiano di Tecnologia (IIT), Via Morego 30, Genoa, 16163, Italy
| | - Giulia Biffi
- Optoelectronics Research Line, Istituto Italiano di Tecnologia (IIT), Via Morego 30, Genoa, 16163, Italy
| | - Yu-Chen Leng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Seda Kutkan
- Optoelectronics Research Line, Istituto Italiano di Tecnologia (IIT), Via Morego 30, Genoa, 16163, Italy
| | - Milena P Arciniegas
- Nanochemistry, Istituto Italiano di Tecnologia (IIT), Via Morego 30, Genoa, 16163, Italy
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Roman Krahne
- Optoelectronics Research Line, Istituto Italiano di Tecnologia (IIT), Via Morego 30, Genoa, 16163, Italy
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13
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Luo WX, Liu XL, Chen X, Wu H, Cong X, Lin ML, Tan PH. A tunable Raman system based on ultrafast laser for Raman excitation profile measurement. Rev Sci Instrum 2021; 92:123904. [PMID: 34972429 DOI: 10.1063/5.0059099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 11/17/2021] [Indexed: 06/14/2023]
Abstract
The measurement of the Raman excitation profile (REP) is of great importance to obtain the energies of van Hove singularities and the lifetime of the excited state involved in the Raman process of semiconductors. In this Note, we develop a simple tunable Raman system based on an ultrafast laser and tunable Raman filters for REP measurement. The system is testified by measuring REP of twisted bilayer graphene, and the corresponding energy of van Hove singularity is determined.
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Affiliation(s)
- Wei-Xia Luo
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xue-Lu Liu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xue Chen
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Heng Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xin Cong
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
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14
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Quan J, Linhart L, Lin ML, Lee D, Zhu J, Wang CY, Hsu WT, Choi J, Embley J, Young C, Taniguchi T, Watanabe K, Shih CK, Lai K, MacDonald AH, Tan PH, Libisch F, Li X. Publisher Correction: Phonon renormalization in reconstructed MoS 2 moiré superlattices. Nat Mater 2021; 20:1167. [PMID: 33824493 DOI: 10.1038/s41563-021-00998-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
- Jiamin Quan
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Lukas Linhart
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
- Institute for Theoretical Physics, Vienna University of Technology, Vienna, Austria
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
| | - Daehun Lee
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Jihang Zhu
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Chun-Yuan Wang
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Wei-Ting Hsu
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Junho Choi
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Jacob Embley
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Carter Young
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | | | | | - Chih-Kang Shih
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Keji Lai
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Allan H MacDonald
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China.
| | - Florian Libisch
- Institute for Theoretical Physics, Vienna University of Technology, Vienna, Austria.
| | - Xiaoqin Li
- Department of Physics, The University of Texas at Austin, Austin, TX, USA.
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15
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Quan J, Linhart L, Lin ML, Lee D, Zhu J, Wang CY, Hsu WT, Choi J, Embley J, Young C, Taniguchi T, Watanabe K, Shih CK, Lai K, MacDonald AH, Tan PH, Libisch F, Li X. Phonon renormalization in reconstructed MoS 2 moiré superlattices. Nat Mater 2021; 20:1100-1105. [PMID: 33753933 DOI: 10.1038/s41563-021-00960-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 02/16/2021] [Indexed: 05/25/2023]
Abstract
In moiré crystals formed by stacking van der Waals materials, surprisingly diverse correlated electronic phases and optical properties can be realized by a subtle change in the twist angle. Here, we discover that phonon spectra are also renormalized in MoS2 twisted bilayers, adding an insight to moiré physics. Over a range of small twist angles, the phonon spectra evolve rapidly owing to ultra-strong coupling between different phonon modes and atomic reconstructions of the moiré pattern. We develop a low-energy continuum model for phonons that overcomes the outstanding challenge of calculating the properties of large moiré supercells and successfully captures the essential experimental observations. Remarkably, simple optical spectroscopy experiments can provide information on strain and lattice distortions in moiré crystals with nanometre-size supercells. The model promotes a comprehensive and unified understanding of the structural, optical and electronic properties of moiré superlattices.
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Affiliation(s)
- Jiamin Quan
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Lukas Linhart
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
- Institute for Theoretical Physics, Vienna University of Technology, Vienna, Austria
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
| | - Daehun Lee
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Jihang Zhu
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Chun-Yuan Wang
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Wei-Ting Hsu
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Junho Choi
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Jacob Embley
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Carter Young
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | | | | | - Chih-Kang Shih
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Keji Lai
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Allan H MacDonald
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China.
| | - Florian Libisch
- Institute for Theoretical Physics, Vienna University of Technology, Vienna, Austria.
| | - Xiaoqin Li
- Department of Physics, The University of Texas at Austin, Austin, TX, USA.
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16
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Pan F, Ni K, Ma Y, Wu H, Tang X, Xiong J, Yang Y, Ye C, Yuan H, Lin ML, Dai J, Zhu M, Tan PH, Zhu Y, Novoselov KS. Phase-Changing in Graphite Assisted by Interface Charge Injection. Nano Lett 2021; 21:5648-5654. [PMID: 34165978 DOI: 10.1021/acs.nanolett.1c01225] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Among many phase-changing materials, graphite is probably the most studied and interesting: the rhombohedral (3R) and hexagonal (2H) phases exhibit dramatically different electronic properties. However, up to now the only way to promote 3R to 2H phase transition is through exposure to elevated temperatures (above 1000 °C); thus, it is not feasible for modern technology. In this work, we demonstrate that 3R to 2H phase transition can be promoted by changing the charged state of 3D graphite, which promotes the repulsion between the layers and significantly reduces the energy barrier between the 3R and 2H phases. In particular, we show that charge transfer from lithium nitride (α-Li3N) to graphite can lower the transition temperature down to 350 °C. The proposed interlayer slipping model potentially offers the control over topological states at the interfaces between different phases, making this system even more attractive for future electronic applications.
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Affiliation(s)
- Fei Pan
- Hefei National Research Center for Physical Sciences at the Microscale, & CAS Key Laboratory of Materials for Energy Conversion & Department of Materials Science and Engineering, University of Science and Technology of China, 96 Jin Zhai Road, Hefei, Anhui 230026, P. R. China
| | - Kun Ni
- Hefei National Research Center for Physical Sciences at the Microscale, & CAS Key Laboratory of Materials for Energy Conversion & Department of Materials Science and Engineering, University of Science and Technology of China, 96 Jin Zhai Road, Hefei, Anhui 230026, P. R. China
| | - Yue Ma
- State Key Laboratory of Solidification Processing, & Center for Nano Energy Materials, & School of Materials Science and Engineering, Northwestern Polytechnical University & Shaanxi Joint Laboratory of Graphene (NPU), Xi' an, Shaanxi 710072, P. R. China
| | - Hongjian Wu
- Department of Physics, National University of Defense Technology, Changsha, Hunan 410073, P. R. China
| | - Xiaoyu Tang
- State Key Laboratory of Solidification Processing, & Center for Nano Energy Materials, & School of Materials Science and Engineering, Northwestern Polytechnical University & Shaanxi Joint Laboratory of Graphene (NPU), Xi' an, Shaanxi 710072, P. R. China
| | - Juan Xiong
- Hefei National Research Center for Physical Sciences at the Microscale, & CAS Key Laboratory of Materials for Energy Conversion & Department of Materials Science and Engineering, University of Science and Technology of China, 96 Jin Zhai Road, Hefei, Anhui 230026, P. R. China
| | - Yaping Yang
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073, P. R. China
| | - Chuanren Ye
- Hefei National Research Center for Physical Sciences at the Microscale, & CAS Key Laboratory of Materials for Energy Conversion & Department of Materials Science and Engineering, University of Science and Technology of China, 96 Jin Zhai Road, Hefei, Anhui 230026, P. R. China
| | - Hong Yuan
- Hefei National Research Center for Physical Sciences at the Microscale, & CAS Key Laboratory of Materials for Energy Conversion & Department of Materials Science and Engineering, University of Science and Technology of China, 96 Jin Zhai Road, Hefei, Anhui 230026, P. R. China
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China
| | - Jiayu Dai
- Department of Physics, National University of Defense Technology, Changsha, Hunan 410073, P. R. China
| | - Mengjian Zhu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, Hunan 410073, P. R. China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China
| | - Yanwu Zhu
- Hefei National Research Center for Physical Sciences at the Microscale, & CAS Key Laboratory of Materials for Energy Conversion & Department of Materials Science and Engineering, University of Science and Technology of China, 96 Jin Zhai Road, Hefei, Anhui 230026, P. R. China
| | - Kostya S Novoselov
- National Graphene Institute, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
- Centre for Advanced 2D Materials, National University of Singapore, 117546, Singapore
- Chongqing 2D Materials Institute, Liangjiang New Area, Chongqing 400714, P. R. China
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Leng YC, Lin ML, Zhou Y, Wu JB, Meng D, Cong X, Li H, Tan PH. Intrinsic effect of interfacial coupling on the high-frequency intralayer modes in twisted multilayer MoTe 2. Nanoscale 2021; 13:9732-9739. [PMID: 34019059 DOI: 10.1039/d1nr01309b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The interfacial coupling at the interface makes the van der Waals heterostructures (vdWHs) exhibit many unique properties that cannot be realized in its constituents. Such a study usually starts with a twisted stack of two flakes exfoliated from the same layered materials to form twisted multilayers, in which the impact of interfacial coupling on the low-frequency interlayer modes had been well understood. However, it is not clear how interfacial coupling affects the high-frequency intralayer modes of twisted multilayers. Herein, we perform high-resolution resonance Raman spectroscopy of the high-frequency intralayer modes in twisted multilayer MoTe2 (tMLM). All the Davydov entities of the out-of-plane intralayer mode are observed and distinguished at 4 K. It is found that the out-of-plane intralayer modes in tMLM are sensitive to its interfacial layer-breathing coupling so that the out-of-plane intralayer modes in tMLM do not show a direct relationship with those of the two constituents. However, the case is quite different for the in-plane intralayer modes in tMLM, whose spectral profile can be fitted by those of the corresponding modes of its constituents. This indicates that the in-plane intralayer modes are localized within the constituents in tMLM because of its negligible interfacial shear coupling at the interface. All the results can be well understood using the vdW model in which only the nearest neighbor interlayer/interfacial interaction is taken into account. This work directly builds the relationship between the Davydov splitting of the high-frequency intralayer vibrations and the low-frequency interlayer vibrations in tMLM, which can be further extended to other twisted materials and the related vdWHs.
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Affiliation(s)
- Yu-Chen Leng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
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Lin ML, Huang JJ. [Difficulties and Policy Recommendations Related to the Deployment of Long-Term Care Resources in Taiwan`s Indigenous Areas]. Hu Li Za Zhi 2021; 68:6-11. [PMID: 33792013 DOI: 10.6224/jn.202104_68(2).02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Changes in the demographic structure in Taiwan have increased the need for long-term care (LTC). Person-centered and community-based care is being advocated. The need to address the specific LTC needs of Taiwan`s indigenous peoples has been a part of national LTC policy since National Long-term Care Plan 2.0 was adopted in 2015. The provision of LTC services and the deployment of related resources in indigenous areas generally lag behind Taiwan`s other areas. Potential reasons for this disparity include lack of in-charge, dedicated units; exclusive use of normative service models in indigenous areas; and conflict between talent cultivation and rooted development. Future policy should focus more on providing cultural care in indigenous areas and on offering more flexible and diversified development possibilities. The implementation of these policies may promote the development of LTC and the successful deployment of LTC resources in Taiwan`s indigenous regions.
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Affiliation(s)
- Miao-Ling Lin
- PhD, RN, Technical Specialist, Long-Term Care Division, Department of Health, Kaohsiung City Government, Taiwan, ROC
| | - Joh-Jong Huang
- PhD, MD, Director-General, Department of Health, Kaohsiung City Government, Taiwan, ROC.
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Lin ML, Leng YC, Cong X, Meng D, Wang J, Li XL, Yu B, Liu XL, Yu XF, Tan PH. Understanding angle-resolved polarized Raman scattering from black phosphorus at normal and oblique laser incidences. Sci Bull (Beijing) 2020; 65:1894-1900. [PMID: 36738054 DOI: 10.1016/j.scib.2020.08.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/04/2020] [Accepted: 07/20/2020] [Indexed: 02/07/2023]
Abstract
The selection rule for angle-resolved polarized Raman (ARPR) intensity of phonons from standard group-theoretical method in isotropic materials would break down in anisotropic layered materials (ALMs) due to birefringence and linear dichroism effects. The two effects result in depth-dependent polarization and intensity of incident laser and scattered signal inside ALMs and thus make a challenge to predict ARPR intensity at any laser incidence direction. Herein, taking in-plane anisotropic black phosphorus as a prototype, we developed a so-called birefringence-linear-dichroism (BLD) model to quantitatively understand its ARPR intensity at both normal and oblique laser incidences by the same set of real Raman tensors for certain laser excitation. No fitting parameter is needed, once the birefringence and linear dichroism effects are considered with the complex refractive indexes. An approach was proposed to experimentally determine real Raman tensor and complex refractive indexes, respectively, from the relative Raman intensity along its principle axes and incident-angle resolved reflectivity by Fresnel's law. The results suggest that the previously reported ARPR intensity of ultrathin ALM flakes deposited on a multilayered substrate at normal laser incidence can be also understood based on the BLD model by considering the depth-dependent polarization and intensity of incident laser and scattered Raman signal induced by both birefringence and linear dichroism effects within ALM flakes and the interference effects in the multilayered structures, which are dependent on the excitation wavelength, thickness of ALM flakes and dielectric layers of the substrate. This work can be generally applicable to any opaque anisotropic crystals, offering a promising route to predict and manipulate the polarized behaviors of related phonons.
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Affiliation(s)
- Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Yu-Chen Leng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Cong
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Da Meng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiahong Wang
- Shenzhen Engineering Center for the Fabrication of Two-Dimensional Atomic Crystals, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Xiao-Li Li
- College of Physics Science and Technology, Hebei University, Baoding 071002, China
| | - Binlu Yu
- Shenzhen Engineering Center for the Fabrication of Two-Dimensional Atomic Crystals, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Xue-Lu Liu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xue-Feng Yu
- Shenzhen Engineering Center for the Fabrication of Two-Dimensional Atomic Crystals, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China; Beijing Academy of Quantum Information Science, Beijing 100193, China.
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Liu Z, Guo K, Hu G, Shi Z, Li Y, Zhang L, Chen H, Zhang L, Zhou P, Lu H, Lin ML, Liu S, Cheng Y, Liu XL, Xie J, Bi L, Tan PH, Deng L, Qiu CW, Peng B. Observation of nonreciprocal magnetophonon effect in nonencapsulated few-layered CrI 3. Sci Adv 2020; 6:6/43/eabc7628. [PMID: 33097544 PMCID: PMC7608833 DOI: 10.1126/sciadv.abc7628] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/03/2020] [Indexed: 05/31/2023]
Abstract
"Magneto-optical" effect refers to a rotation of polarization plane, which has been widely studied in traditional ferromagnetic metal and insulator films and scarcely in two-dimensional layered materials. Here, we uncover a new nonreciprocal magnetophonon Raman scattering effect in ferromagnetic few-layer CrI3 We observed a rotation of the polarization plane of inelastically scattered light between -20o and +60o that are tunable by an out-of-plane magnetic field from -2.5 to 2.5 T. It is experimentally observed that the degree of polarization can be magnetically manipulated between -20 and 85%. This work raises a new magneto-optical phenomenon and could create opportunities of applying two-dimensional ferromagnetic materials in Raman lasing, topological photonics, and magneto-optical modulator for information transport and storage.
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Affiliation(s)
- Zhen Liu
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Kai Guo
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Guangwei Hu
- Department of Electrical and Computer Engineering, National University of Singapore, 117583, Singapore
| | - Zhongtai Shi
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yue Li
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Linbo Zhang
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Haiyan Chen
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Li Zhang
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Peiheng Zhou
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Haipeng Lu
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing 100083, China
| | - Sizhao Liu
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, China
| | - Yingchun Cheng
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, China
| | - Xue Lu Liu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing 100083, China
| | - Jianliang Xie
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Lei Bi
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing 100083, China
| | - Longjiang Deng
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, 117583, Singapore.
| | - Bo Peng
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.
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Dhanabalan B, Leng YC, Biffi G, Lin ML, Tan PH, Infante I, Manna L, Arciniegas MP, Krahne R. Directional Anisotropy of the Vibrational Modes in 2D-Layered Perovskites. ACS Nano 2020; 14:4689-4697. [PMID: 32275388 PMCID: PMC8007126 DOI: 10.1021/acsnano.0c00435] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The vibrational modes in organic/inorganic layered perovskites are of fundamental importance for their optoelectronic properties. The hierarchical architecture of the Ruddlesden-Popper phase of these materials allows for distinct directionality of the vibrational modes with respect to the main axes of the pseudocubic lattice in the octahedral plane. Here, we study the directionality of the fundamental phonon modes in single exfoliated Ruddlesden-Popper perovskite flakes with polarized Raman spectroscopy at ultralow frequencies. A wealth of Raman bands is distinguished in the range from 15 to 150 cm-1 (2-15 meV), whose features depend on the organic cation species, on temperature, and on the direction of the linear polarization of the incident light. By controlling the angle of the linear polarization of the excitation laser with respect to the in-plane axes of the octahedral layer, we gain detailed information on the symmetry of the vibrational modes. The choice of two different organic moieties, phenethylammonium (PEA) and butylammonium (BA), allows us to discern the influence of the linker molecules, evidencing strong anisotropy of the vibrations for the (PEA)2PbBr4 samples. Temperature-dependent Raman measurements reveal that the broad phonon bands observed at room temperature consist of a series of sharp modes and that such mode splitting strongly differs for the different organic moieties and vibrational bands. Softer molecules such as BA result in lower vibrational frequencies and splitting into fewer modes, while more rigid molecules such as PEA lead to higher frequency oscillations and larger number of Raman peaks at low temperature. Interestingly, in distinct bands the number of peaks in the Raman bands is doubled for the rigid PEA compared to the soft BA linkers. Our work shows that the coupling to specific vibrational modes can be controlled by the incident light polarization and choice of the organic moiety, which could be exploited for tailoring exciton-phonon interaction, and for optical switching of the optoelectronic properties of such 2D layered materials.
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Affiliation(s)
- Balaji Dhanabalan
- Istituto
Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genoa, Italy
- Dipartimento
di Chimica e Chimica Industriale, Università
degli Studi di Genova, Via Dodecaneso, 31, 16146 Genova, Italy
| | - Yu-Chen Leng
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- Center
of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100190 Beijing, China
| | - Giulia Biffi
- Istituto
Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genoa, Italy
- Dipartimento
di Chimica e Chimica Industriale, Università
degli Studi di Genova, Via Dodecaneso, 31, 16146 Genova, Italy
| | - Miao-Ling Lin
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- Center
of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100190 Beijing, China
| | - Ping-Heng Tan
- State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- Center
of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100190 Beijing, China
| | - Ivan Infante
- Istituto
Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genoa, Italy
| | - Liberato Manna
- Istituto
Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genoa, Italy
| | | | - Roman Krahne
- Istituto
Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genoa, Italy
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Lin ML, Huang JJ, Li SH, Lee FH, Hou MF, Wang HH. Effects of different reminder strategies on first-time mammography screening among women in Taiwan. BMC Health Serv Res 2020; 20:114. [PMID: 32050951 PMCID: PMC7017575 DOI: 10.1186/s12913-020-4948-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 01/30/2020] [Indexed: 11/18/2022] Open
Abstract
Background The study’s purpose was to examine the effectiveness of different reminder strategies on first-time free mammography screening among middle-aged women in Taiwan. Methods A quasi-experimental design with random assignment was adopted to divide the participants into three Reminder Strategies groups (mail reminder, telephone reminder, and combined mail and telephone reminders) and one control group. This study recruited 240 eligible middle-aged women, and 205 of them completed the study. Upon the completion of data collection, mail reminders were provided to women of the first group; telephone reminders were provided to the second group; mail followed by telephone reminders were provided to the third group, and the usual postcards were provided to the control group 1 month after the interventions. Two follow-up assessments were conducted 1 and 3 months after the intervention to collect mammography-screening behaviors from all groups. Results The findings showed that, compared to the control group, more participants in the intervention groups underwent mammography screening after receiving reminder interventions. Telephone contact as reminder was found to have the most significant influence among the interventions (OR = 5.0556; 95% CI = 2.0422–13.5722). Conclusions Government and healthcare providers are recommended to consider adopting the telephone reminder strategy to encourage women to undergo their first-time mammography screening.
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Affiliation(s)
- Miao-Ling Lin
- Long-Term Care Division, Department of Health, Kaohsiung City Government, No. 2, Sihwei 3rd Road, Lingya District, Kaohsiung City, 80203, Taiwan.,College of Nursing, Kaohsiung Medical University, No. 2, Sihwei 3rd Road, Lingya District, Kaohsiung City, 80203, Taiwan
| | - Joh-Jong Huang
- Graduate Institute of Gender Studies, Kaohsiung Medical University, No. 100 Shih-Chuan 1st Road, San-Ming District, Kaohsiung, 80708, Taiwan
| | - Shu-Hua Li
- Long-Term Care Division, Department of Health, Kaohsiung City Government, No. 2, Sihwei 3rd Road, Lingya District, Kaohsiung City, 80203, Taiwan
| | - Fang-Hsin Lee
- Department of Nursing, Chung Hwa University of Medical Technology, No. 89, Wenhua 1st St., Rende District, Tainan, 71703, Taiwan
| | - Ming-Feng Hou
- Graduate Institute of Clinical Medicine, Kaohsiung Medical University, No. 100 Shih-Chuan 1st Road, San-Ming District, Kaohsiung, 80708, Taiwan
| | - Hsiu-Hung Wang
- College of Nursing, Kaohsiung Medical University, No. 2, Sihwei 3rd Road, Lingya District, Kaohsiung City, 80203, Taiwan. .,College of Nursing, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung, 807, Taiwan.
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Wang YC, Lu YP, Wang JH, Liang CK, Chou MY, Lin YT, Chen FT, Lin ML, Lee SH, Huang JJ. The Effectiveness of a Timely Discharge Plan in Older Adults: A Prospective Hospital-Based Cohort Study in Southern Taiwan. Aging Med Healthc 2019. [DOI: 10.33879/amh.2019.1902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Lin ML, Miscuglio M, Polovitsyn A, Leng YC, Martín-García B, Moreels I, Tan PH, Krahne R. Giant-Shell CdSe/CdS Nanocrystals: Exciton Coupling to Shell Phonons Investigated by Resonant Raman Spectroscopy. J Phys Chem Lett 2019; 10:399-405. [PMID: 30626187 DOI: 10.1021/acs.jpclett.8b03211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The interaction between excitons and phonons in semiconductor nanocrystals plays a crucial role in the exciton energy spectrum and dynamics, and thus in their optical properties. We investigate the exciton-phonon coupling in giant-shell CdSe/CdS core-shell nanocrystals via resonant Raman spectroscopy. The Huang-Rhys parameter is evaluated by the intensity ratio of the longitudinal-optical (LO) phonon of CdS with its first multiscattering (2LO) replica. We used four different excitation wavelengths in the range from the onset of the CdS shell absorption to well above the CdS shell band edge to get insight into resonance effects of the CdS LO phonon with high-energy excitonic transitions. The isotropic spherical giant-shell nanocrystals show consistently stronger exciton-phonon coupling as compared to the anisotropic rod-shaped dot-in-rod (DiR) architecture, and the 2LO/LO intensity ratio decreases for excitation wavelengths approaching the CdS band edge. The strong exciton-phonon coupling in the spherical giant-shell nanocrystals can be related to the delocalization of the electronic wave functions. Furthermore, we observe the radial breathing modes of the GS nanocrystals and their overtones by ultralow frequency Raman spectroscopy with nonresonant excitation, using laser energies well below the band gap of the heteronanocrystals, and highlight the differences between higher-order optical and acoustic phonon modes.
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Affiliation(s)
- Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation , University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Mario Miscuglio
- Istituto Italiano di Tecnologia (IIT) , Via Morego 30 , 16163 Genoa , Italy
| | - Anatolii Polovitsyn
- Department of Chemistry , Ghent University , Krijgslaan 281-S3 , 9000 Gent , Belgium
| | - Yu-Chen Leng
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation , University of Chinese Academy of Sciences , Beijing 100190 , China
| | | | - Iwan Moreels
- Department of Chemistry , Ghent University , Krijgslaan 281-S3 , 9000 Gent , Belgium
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation , University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Roman Krahne
- Istituto Italiano di Tecnologia (IIT) , Via Morego 30 , 16163 Genoa , Italy
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Cong X, Wu JB, Lin ML, Liu XL, Shi W, Venezuela P, Tan PH. Stokes and anti-Stokes Raman scattering in mono- and bilayer graphene. Nanoscale 2018; 10:16138-16144. [PMID: 30117506 DOI: 10.1039/c8nr04554b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Stokes and anti-Stokes Raman spectroscopy associated with the intervalley double resonance process in carbon materials is a unique technique to reveal the relationship between their characteristic electronic band structures and phonon dispersion. In graphene, the dominant resonant behavior for its 2D mode is an intervalley triple resonance Raman process. In this paper, we report the Stokes and anti-Stokes Raman scattering of the 2D mode in pristine graphene. The excitation energy (Eex)-dependent frequency discrepancy between anti-Stokes and Stokes components of the 2D mode (Δω(2D)) is observed, which is in good agreement with the theoretical results. This is attributed to the nonlinear dispersion of the in-plane transverse optical (iTO) phonon branch near the K point, confirmed by the nonlinear Eex-dependent frequency of the 2D mode (ω(2D)) in the range of 1.58-3.81 eV. The wavevector-dependent phonon group velocity of the iTO phonon branch is directly derived from Δω(2D). The Stokes and anti-Stokes Raman scattering of the D mode in defected graphene and the 2D mode in bilayer graphene associated with intervalley double resonance Raman processes is also reported.
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Affiliation(s)
- Xin Cong
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
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Lin ML, Tan QH, Wu JB, Chen XS, Wang JH, Pan YH, Zhang X, Cong X, Zhang J, Ji W, Hu PA, Liu KH, Tan PH. Moiré Phonons in Twisted Bilayer MoS 2. ACS Nano 2018; 12:8770-8780. [PMID: 30086224 DOI: 10.1021/acsnano.8b05006] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The material choice, layer thickness, and twist angle widely enrich the family of van der Waals heterostructures (vdWHs), providing multiple degrees of freedom to engineer their optical and electronic properties. The moiré patterns in vdWHs create a periodic potential for electrons and excitons to yield many interesting phenomena, such as Hofstadter butterfly spectrum and moiré excitons. Here, in the as-grown/transferred twisted bilayer MoS2 (tBLMs), one of the simplest prototypes of vdWHs, we show that the periodic potentials of moiré patterns also modify the properties of phonons of its monolayer MoS2 constituent to generate Raman modes related to moiré phonons. These Raman modes correspond to zone-center phonons in tBLMs, which are folded from the off-center phonons in monolayer MoS2. However, the folded phonons related to crystallographic superlattices are not observed in the Raman spectra. By varying the twist angle, the moiré phonons of tBLM can be exploited to map the phonon dispersions of the monolayer constituent. The lattice dynamics of the moiré phonons are modulated by the patterned interlayer coupling resulting from periodic potential of moiré patterns, as confirmed by density functional theory calculations. The Raman intensity related to moiré phonons in all tBLMs are strongly enhanced when the excitation energy approaches the C exciton energy. This study can be extended to various vdWHs to deeply understand their Raman spectra, moiré phonons, lattice dynamics, excitonic effects, and interlayer coupling.
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Affiliation(s)
- Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- CAS Center of Excellence in Topological Quantum Computation and College of Materials Science and Opto-Electronic Technology , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Qing-Hai Tan
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- CAS Center of Excellence in Topological Quantum Computation and College of Materials Science and Opto-Electronic Technology , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Jiang-Bin Wu
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
| | - Xiao-Shuang Chen
- School of Materials Science and Engineering, MOE Key Laboratory of Micro-Systems and Micro-Structures Manufacturing , Harbin Institute of Technology , Harbin 150080 , China
| | - Jin-Huan Wang
- State Key Laboratory of Mesoscopic Physics, School of Physics and Collaborative Innovation Center Quantum Matter , Peking University , Beijing 100871 , China
| | - Yu-Hao Pan
- Department of Physics , Renmin University of China , Beijing 100872 , China
| | - Xin Zhang
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
| | - Xin Cong
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- CAS Center of Excellence in Topological Quantum Computation and College of Materials Science and Opto-Electronic Technology , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Jun Zhang
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- CAS Center of Excellence in Topological Quantum Computation and College of Materials Science and Opto-Electronic Technology , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Wei Ji
- Department of Physics , Renmin University of China , Beijing 100872 , China
| | - Ping-An Hu
- School of Materials Science and Engineering, MOE Key Laboratory of Micro-Systems and Micro-Structures Manufacturing , Harbin Institute of Technology , Harbin 150080 , China
| | - Kai-Hui Liu
- State Key Laboratory of Mesoscopic Physics, School of Physics and Collaborative Innovation Center Quantum Matter , Peking University , Beijing 100871 , China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- CAS Center of Excellence in Topological Quantum Computation and College of Materials Science and Opto-Electronic Technology , University of Chinese Academy of Sciences , Beijing 100049 , China
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Lin T, Cong X, Lin ML, Liu XL, Tan PH. The phonon confinement effect in two-dimensional nanocrystals of black phosphorus with anisotropic phonon dispersions. Nanoscale 2018; 10:8704-8711. [PMID: 29701212 DOI: 10.1039/c8nr01531g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The RWL model for the phonon confinement effect in nanocrystals (NCs) had been found to result in deviations and limitations for crystals exhibiting obvious anisotropic phonon dispersions and modified models have been proposed to overcome these deficiencies. Here, we examine this issue in black phosphorus (BP), a typical anisotropic two-dimensional crystal exhibiting pronounced anisotropy in phonon dispersions. A detailed study is performed on the Raman spectra of BP NCs prepared by the ion implantation technique. With decreasing NC size, the peak positions of the three characteristic Raman modes, Ag1, B2g and Ag2 modes, remain almost unchanged, while the Ag1 and Ag2 modes show significant asymmetrical broadening tails towards higher- and lower-frequency sides, respectively. It is found that the RWL model based on one-dimensional phonon dispersion along Γ-Y and Γ-X axes in the Brillouin zone (BZ) cannot interpret the unusual frequency invariance and inhomogeneous line shape broadening of these three modes. However, after considering the contribution of two-dimensional anisotropic phonon dispersions from the whole BZ, the frequency and asymmetrical broadening of the Ag1 and Ag2 modes can be well reproduced. This study demonstrates that the RWL model can be applicable for crystals with anisotropic phonon dispersions once the phonons in the whole two-dimensional or three-dimensional BZ are properly taken into account, and provides a physically sound route into understanding the phonon confinement effect for anisotropic systems.
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Affiliation(s)
- Tong Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
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Abstract
OBJECTIVES Public health nurses are responsible for promoting and managing the health of community members, and if they do not have enough physical activity or ignore their own health, not only will their own health decline but the quality of life of the public will also be affected. This study investigated the physical activity of public health nurses and analysed the effects of attitudes, subjective norms, perceived behavioural control and behavioural intention to engage in physical activity. METHODS This study adopted a cross-sectional research design, and convenience sampling was used to select the research subjects. 198 public health nurses were invited to participate, and 172 completed the questionnaire. Multiple linear regression was used to analyse the influencing factors of physical activity intention and physical activity. RESULTS Attitudes towards physical activity and perceived behavioural control of physical activity affected physical activity intention. When they had higher behavioural intention, their physical activity behaviour also improved. The physical activity intention significantly influenced the number of days that they had engaged in vigorous physical activity (95% CI 0.1786 to 0.3060, p<0.0001), and significantly influenced the number of days that they walked daily for 10 min (95% CI 0.2158 to 0.4144, p<0.0001), and also significantly influenced their daily sedentary time (95% CI -0.3020 to 0.0560, p=0.0046). CONCLUSIONS Encouraging public health nurses to heed their own health and motivating them to engage in physical activity warrants attention from policy-makers and government health agencies.
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Affiliation(s)
- Miao-Ling Lin
- College of Nursing, Kaohsiung Medical University, Kaohsiung, Taiwan
- Long-Term Care Division, Department of Health, Kaohsiung City Government, Kaohsiung, Taiwan
| | - Joh-Jong Huang
- Graduate Institute of Gender Studies, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Hung-Yi Chuang
- Department of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Hsiu-Min Tsai
- Department of Nursing, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| | - Hsiu-Hung Wang
- College of Nursing, Kaohsiung Medical University, Kaohsiung, Taiwan
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Abstract
Graphene-based materials exhibit remarkable electronic, optical, and mechanical properties, which has resulted in both high scientific interest and huge potential for a variety of applications. Furthermore, the family of graphene-based materials is growing because of developments in preparation methods. Raman spectroscopy is a versatile tool to identify and characterize the chemical and physical properties of these materials, both at the laboratory and mass-production scale. This technique is so important that most of the papers published concerning these materials contain at least one Raman spectrum. Thus, here, we systematically review the developments in Raman spectroscopy of graphene-based materials from both fundamental research and practical (i.e., device applications) perspectives. We describe the essential Raman scattering processes of the entire first- and second-order modes in intrinsic graphene. Furthermore, the shear, layer-breathing, G and 2D modes of multilayer graphene with different stacking orders are discussed. Techniques to determine the number of graphene layers, to probe resonance Raman spectra of monolayer and multilayer graphenes and to obtain Raman images of graphene-based materials are also presented. The extensive capabilities of Raman spectroscopy for the investigation of the fundamental properties of graphene under external perturbations are described, which have also been extended to other graphene-based materials, such as graphene quantum dots, carbon dots, graphene oxide, nanoribbons, chemical vapor deposition-grown and SiC epitaxially grown graphene flakes, composites, and graphene-based van der Waals heterostructures. These fundamental properties have been used to probe the states, effects, and mechanisms of graphene materials present in the related heterostructures and devices. We hope that this review will be beneficial in all the aspects of graphene investigations, from basic research to material synthesis and device applications.
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Affiliation(s)
- Jiang-Bin Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
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Li H, Wu JB, Ran F, Lin ML, Liu XL, Zhao Y, Lu X, Xiong Q, Zhang J, Huang W, Zhang H, Tan PH. Interfacial Interactions in van der Waals Heterostructures of MoS 2 and Graphene. ACS Nano 2017; 11:11714-11723. [PMID: 29068659 DOI: 10.1021/acsnano.7b07015] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Interfacial coupling between neighboring layers of van der Waals heterostructures (vdWHs), formed by vertically stacking more than two types of two-dimensional materials (2DMs), greatly affects their physical properties and device performance. Although high-resolution cross-sectional scanning tunneling electron microscopy can directly image the atomically sharp interfaces in the vdWHs, the interfacial coupling and lattice dynamics of vdWHs formed by two different types of 2DMs, such as semimetal and semiconductor, are not clear so far. Here, we report the ultralow-frequency Raman spectroscopy investigation on interfacial couplings in the vdWHs formed by graphene and MoS2 flakes. Because of the significant interfacial layer-breathing couplings between MoS2 and graphene flakes, a series of layer-breathing modes with frequencies dependent on their layer numbers are observed in the vdWHs, which can be described by the linear chain model. It is found that the interfacial layer-breathing force constant between MoS2 and graphene, α0⊥(I) = 60 × 1018 N/m3, is comparable with the layer-breathing force constant of multilayer MoS2 and graphene. The results suggest that the interfacial layer-breathing couplings in the vdWHs formed by MoS2 and graphene flakes are not sensitive to their stacking order and twist angle between the two constituents. Our results demonstrate that the interfacial interlayer coupling in vdWHs formed by two-dimensional semimetals and semiconductors can lead to new lattice vibration modes, which not only can be used to measure the interfacial interactions in vdWHs but also is beneficial to fundamentally understand the properties of vdWHs for further engineering the vdWHs-based electronic and photonic devices.
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Affiliation(s)
- Hai Li
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University , 30 South Puzhu Road, Nanjing 211816, P.R. China
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Jiang-Bin Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors , Chinese Academy of Sciences, Beijing 100083, China
| | - Feirong Ran
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University , 30 South Puzhu Road, Nanjing 211816, P.R. China
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors , Chinese Academy of Sciences, Beijing 100083, China
| | - Xue-Lu Liu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors , Chinese Academy of Sciences, Beijing 100083, China
| | - Yanyuan Zhao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371, Singapore
| | - Xin Lu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371, Singapore
| | - Qihua Xiong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371, Singapore
- NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University , Singapore 639798, Singapore
| | - Jun Zhang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors , Chinese Academy of Sciences, Beijing 100083, China
- CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences , Beijing 100190, China
| | - Wei Huang
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University , 30 South Puzhu Road, Nanjing 211816, P.R. China
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), SICAM, Nanjing University of Posts & Telecommunications , 9 Wenyuan Road, Nanjing 210023, China
- Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU) , 127 West Youyi Road, Xi'an 710072, China
| | - Hua Zhang
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors , Chinese Academy of Sciences, Beijing 100083, China
- CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences , Beijing 100190, China
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Miscuglio M, Lin ML, Di Stasio F, Tan PH, Krahne R. Confined Acoustic Phonons in Colloidal Nanorod Heterostructures Investigated by Nonresonant Raman Spectroscopy and Finite Elements Simulations. Nano Lett 2016; 16:7664-7670. [PMID: 27960519 DOI: 10.1021/acs.nanolett.6b03706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Lattice vibrational modes in cadmium chalcogenide nanocrystals (NCs) have a strong impact on the carrier dynamics of excitons in such confined systems and on the optical properties of these nanomaterials. A prominent material for light emitting applications are CdSe/CdS core-shell dot-in-rods. Here we present a detailed investigation of the acoustic phonon modes in such dot-in-rods by nonresonant Raman spectroscopy with laser excitation energy lower than their bandgap. With high signal-to-noise ratio in the frequency range from 5-50 cm-1, we reveal distinct Raman bands that can be related to confined extensional and radial-breathing modes (RBM). Comparison of the experimental results with finite elements simulation and analytical analysis gives detailed insight into the localized nature of the acoustic vibration modes and their resonant frequencies. In particular, the RBM of dot-in-rods cannot be understood by an oscillation of a CdSe sphere embedded in a CdS rod matrix. Instead, the dot-in-rod architecture leads to a reduction of the sound velocity in the core region of the rod, which results in a redshift of the rod RBM frequency and localization of the phonon induced strain in vicinity of the core where optical transitions occur. Such localized effects potentially can be exploited as a tool to tune exciton-phonon coupling in nanocrystal heterostructures.
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Affiliation(s)
- Mario Miscuglio
- Nanochemistry Department, Istituto Italiano di Tecnologia , Via Morego 30, 16163 Genova, Italy
- Dipartimento di Chimica e Chimica Industriale, Università di Genova , Via Dodecaneso 31, 16146 Genova, Italy
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083, China
| | - Francesco Di Stasio
- Nanochemistry Department, Istituto Italiano di Tecnologia , Via Morego 30, 16163 Genova, Italy
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083, China
| | - Roman Krahne
- Nanochemistry Department, Istituto Italiano di Tecnologia , Via Morego 30, 16163 Genova, Italy
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Lee FH, Wang HH, Tsai HM, Lin ML. Factors associated with receiving Pap tests among married immigrant women of Vietnamese origin in southern Taiwan. Women Health 2015; 56:243-56. [PMID: 26362802 DOI: 10.1080/03630242.2015.1088113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The purpose of this study was to explore the factors associated with Pap testing among married immigrant women of Vietnamese origin residing in Taiwan, including demographics, knowledge of cervical cancer, knowledge of Pap tests, fatalism, attitudes toward cervical cancer, and barriers to receiving Pap tests. A cross-sectional correlational design was used. Data were collected from July 2012 to January 2013. Participants were recruited through snowball sampling in two communities in Southern Taiwan. A total of 451 married immigrant women of Vietnamese origin aged 30 years and over were invited to participate in the study and 427 participated. Data analysis included descriptive statistics and multivariate logistic regression. Participants with no children were significantly less likely to have received a Pap test (odds ratio = 0.278, 95% confidence interval [CI] = 0.135-0.569); each additional point of knowledge about Pap tests increased the likelihood of having a Pap test by 19% (odds ratio = 1.190, 95% CI = 1.093-1.297), and each additional point in barriers to receiving Pap tests decreased the chances of having received a Pap test (odds ratio = 0.714, 95% CI = 0.637-0.800). The results can provide governments with a reference for developing policies for cervical cancer prevention among married immigrant Vietnamese women.
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Affiliation(s)
- Fang-Hsin Lee
- a Department of Nursing , Chung Hwa University of Medical Technology , Tainan , Taiwan
| | - Hsiu-Hung Wang
- b College of Nursing , Kaohsiung Medical University , Kaohsiung , Taiwan
| | - Hsiu-Min Tsai
- c Department of Nursing , Chang Gung University of Science and Technology , Taoyuan , Taiwan
| | - Miao-Ling Lin
- d Health Management Division , Kaohsiung City Government Department of Health , Taiwan
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Yang YM, Wang HH, Lee FH, Lin ML, Lin PC. Health Empowerment Among Immigrant Women in Transnational Marriages in Taiwan. J Nurs Scholarsh 2014; 47:135-42. [DOI: 10.1111/jnu.12110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2014] [Indexed: 12/01/2022]
Affiliation(s)
- Yung-Mei Yang
- Assistant Professor, College of Nursing; Kaohsiung Medical University; Kaohsiung Taiwan
| | - Hsiu-Hung Wang
- Professor, College of Nursing; Kaohsiung Medical University; Kaohsiung Taiwan
| | - Fang-Hsin Lee
- Assistant Professor, Department of Nursing; Chung Hwa University of Medical Technology; Tainan Taiwan
| | - Miao-Ling Lin
- Section Head, Department of Health; Kaohsiung City Government; Kaohsiung Taiwan
| | - Pei-Chao Lin
- Doctoral Candidate; College of Nursing, Kaohsiung Medical University; Kaohsiung Taiwan
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Chen CH, Lin ML, Ong PL, Yang JT. Novel Multiple Apoptotic Mechanism of Shikonin in Human Glioma Cells. Ann Surg Oncol 2012; 19:3097-106. [DOI: 10.1245/s10434-012-2324-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Indexed: 11/18/2022]
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Wang HH, Lin ML, Yang YM, Tsai HM, Huang JJ. The effects of group health education on childbearing knowledge, attitude, and behaviour among Southeast Asian immigrant women in Taiwan. Midwifery 2011; 28:754-9. [PMID: 21920646 DOI: 10.1016/j.midw.2011.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 03/01/2011] [Accepted: 07/24/2011] [Indexed: 10/17/2022]
Abstract
OBJECTIVES to explore the effects of a group health education programme on the childbearing knowledge, attitude, and behaviours among Southeast Asian immigrant women in Taiwan. DESIGN a quasi-experimental design with convenience sampling was used. SETTING participants living in Kaohsiung County, Taiwan, were randomly divided by districts into either the experimental group or the control group. PARTICIPANTS one hundred Southeast Asian immigrant women were recruited as research participants. Among the 100 participants, 50 were in the experimental group and 50 were in the control group. A total of 99 participants completed the entire research procedure. METHODS a structured interview was used to evaluate the effects of a group health education programme. MEASUREMENTS the interview consisted of four measurements: the Demographic Inventory Scale, the Childbearing Knowledge Scale, the Childbearing Attitude Scale, and the Childbearing Planning Scale. FINDINGS after employing the group health education intervention, statistically significant changes from the pre-test to the post-test were found in the experimental group's scores for the Childbearing Knowledge Scale (P<0.0001), the Childbearing Attitude Scale (P<0.01), and the Childbearing Planning Scale (P<0.0001). The study's results indicated that providing education through group learning with guidance and support in childbearing health significantly improved Southeast Asian immigrant women's childbearing health knowledge, attitudes, and behaviours. CONCLUSION an appropriate, community-based group health education programme can create awareness for childbearing health among Southeast Asian immigrant women in Taiwan and improve their childbearing attitudes and behaviours.
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Affiliation(s)
- Hsiu-Hung Wang
- Kaohsiung Medical University College of Nursing, No. 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.
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Tsai HM, Wang HH, Lin ML, Yang YM. Childbearing KAP in Minority of Southeast Asian. Nurs Outlook 2010. [DOI: 10.1016/j.outlook.2010.02.142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ueki T, Nishidate T, Park JH, Lin ML, Shimo A, Hirata K, Nakamura Y, Katagiri T. Involvement of elevated expression of multiple cell-cycle regulator, DTL/RAMP (denticleless/RA-regulated nuclear matrix associated protein), in the growth of breast cancer cells. Oncogene 2008; 27:5672-83. [PMID: 18542055 DOI: 10.1038/onc.2008.186] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
To investigate the detailed molecular mechanism of mammary carcinogenesis and discover novel therapeutic targets, we previously analysed gene expression profiles of breast cancers. We here report characterization of a significant role of DTL/RAMP (denticleless/RA-regulated nuclear matrix associated protein) in mammary carcinogenesis. Semiquantitative RT-PCR and northern blot analyses confirmed upregulation of DTL/RAMP in the majority of breast cancer cases and all of breast cancer cell lines examined. Immunocytochemical and western blot analyses using anti-DTL/RAMP polyclonal antibody revealed cell-cycle-dependent localization of endogenous DTL/RAMP protein in breast cancer cells; nuclear localization was observed in cells at interphase and the protein was concentrated at the contractile ring in cytokinesis process. The expression level of DTL/RAMP protein became highest at G(1)/S phases, whereas its phosphorylation level was enhanced during mitotic phase. Treatment of breast cancer cells, T47D and HBC4, with small-interfering RNAs against DTL/RAMP effectively suppressed its expression and caused accumulation of G(2)/M cells, resulting in growth inhibition of cancer cells. We further demonstrate the in vitro phosphorylation of DTL/RAMP through an interaction with the mitotic kinase, Aurora kinase-B (AURKB). Interestingly, depletion of AURKB expression with siRNA in breast cancer cells reduced the phosphorylation of DTL/RAMP and decreased the stability of DTL/RAMP protein. These findings imply important roles of DTL/RAMP in growth of breast cancer cells and suggest that DTL/RAMP might be a promising molecular target for treatment of breast cancer.
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Affiliation(s)
- T Ueki
- Laboratory of Molecular Medicine, Human Genome Center, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan
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Lin ML, Wang HH. Prenatal examination behavior of Southeast Asian pregnant women in Taiwan: A questionnaire survey. Int J Nurs Stud 2008; 45:697-705. [PMID: 17339036 DOI: 10.1016/j.ijnurstu.2006.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2006] [Revised: 11/30/2006] [Accepted: 12/10/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND There is growing concern about the factors affecting the prenatal examinations of immigrant women. OBJECTIVES The purpose of this study was to examine the relationships between the knowledge of pregnancy, attitude toward pregnancy and experience of medical services, and prenatal examination behavior of pregnant Southeast Asian women in Taiwan. DESIGN This was a cross-sectional study with a structured questionnaire administered to participants. SETTING Participants were recruited from the community health centers in Kaohsiung County, Taiwan. PARTICIPANTS The sampling criteria were as follows: each subject was to (a) have come from a Southeast Asian country, (b) be over 28 weeks pregnant to less than one year postpartum, (c) be able to communicate either in Mandarin or Taiwanese, and (d) be willing to participate in the research after hearing an explanation of it. As a result, 140 participants were recruited. A total of 132 participants completed the questionnaire and were used for data analysis. METHODS The participants completed structured questionnaires, which included the Demographic Inventory Scale, Knowledge of Pregnancy Scale, Attitudes toward Pregnancy Scale, Experience of Medical Services Scale and the Prenatal Examination Behavior Scale. RESULTS Findings show that 80.3% of the subjects attended their first-time prenatal examination during the first trimester and 59.1% of the subjects evaluated their prenatal examinations as being adequate. Their attitude toward childbearing was significantly correlated with their prenatal examination behavior, including the initial time of prenatal examination and frequencies of prenatal examinations during pregnancy. Positive attitudes toward childbearing and prenatal examination, and the number of years spent in Taiwan were all significant predictive factors of frequencies of prenatal examinations during pregnancy. The findings of this study can not only help healthcare professionals understand the prenatal examination behavior and related factors of the participants, but also provide guidance to healthcare professionals as they assist these pregnant Southeast Asian women in Taiwan in developing childbearing and family plans. CONCLUSION The attitude toward childbearing of the participants was significantly correlated with their prenatal examination behavior. They require professional help in seeking out appropriate medical services that will improve their healthcare quality during pregnancy.
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Affiliation(s)
- Miao-Ling Lin
- Health Bureau of Kaohsiung County, Health Promotion Section, No, 830-1, Chengging Rd., Niaosong Shiang, Kaohsiung County 830, Taiwan, ROC
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Ong PL, Weng BC, Lu FJ, Lin ML, Chang TT, Hung RP, Chen CH. The anticancer effect of protein-extract from Bidens alba in human colorectal carcinoma SW480 cells via the reactive oxidative species- and glutathione depletion-dependent apoptosis. Food Chem Toxicol 2007; 46:1535-47. [PMID: 18226850 DOI: 10.1016/j.fct.2007.12.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 11/30/2007] [Accepted: 12/09/2007] [Indexed: 10/22/2022]
Abstract
Bidens alba has been used for healing cuts, injuries, swellings, hypertension, jaundice, and diabetes in some countries. However, the effect of B. alba on human cancer remains poorly understood. The goal of this study was to investigate whether B. alba protein-extract could have an anticancer property against human colorectal cancer. The human colorectal cancer SW 480 cells treated with the protein-extract of B. alba would cause marked DNA damages and apoptosis-related cellular morphologies. Treatment with 225 microg/ml B. alba protein-extract also led to the SW480 cells to produce readily intracellular reactive oxygen species (ROS) after 1h of treatment and last to 24 h. The intracellular glutathione (GSH) depletion occurred after 12-24h of treatment. The treatment of the protein-extract would also caused mitochondrial transmembrane potential (DeltaPsi(m)) to decrease and cytosolic cytochrome c to increase. The caspase 3/7 activities were activated from 3 to 6 h after the treatment. The percentages of apoptosis induced by the protein-extract of B. alba decreased 26.4%, 10.1%, and 29.4% when the SW 480 cells were pretreated with Vitamin C, N-acetylcysteine, and Boc-Asp(OMe)-fmk, respectively. Taken together, we demonstrated for the first time that the protein-extract of B. alba could induce apoptosis that was related to the ROS production and GSH depletion in human colorectal cancer. The protein-extract of B. alba might have therapeutic value against the human colorectal cancer.
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Affiliation(s)
- Ping-Lin Ong
- Department of Biochemical Science and Technology, College of Life Sciences, National Chiayi University, Chiayi, Taiwan
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Sun KH, Tang SJ, Lin ML, Wang YS, Sun GH, Liu WT. Monoclonal antibodies against human ribosomal P proteins penetrate into living cells and cause apoptosis of Jurkat T cells in culture. Rheumatology (Oxford) 2001; 40:750-6. [PMID: 11477279 DOI: 10.1093/rheumatology/40.7.750] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE This study was designed to determine the role of autoantibodies to the ribosomal P protein (anti-P Abs) in the pathogenesis of systemic lupus erythematosus (SLE) using monoclonal anti-P antibodies (anti-P mAbs). METHODS Anti-P mAbs were prepared by a standard hybridoma procedure using recombinant human P1 and P2 proteins as immunogens. We studied the reactivities of these mAbs to P proteins, their binding and penetration capabilities in different cell lines and their apoptotic effects on Jurkat T cells. RESULTS In addition to recognizing human P0, P1 and P2 proteins, the anti-P mAb 9B6-4 bound to 20-40% and penetrated 50-90% of astrocytes, Jurkat T cells and lung cancer cells via the P0 surface protein. Treatment with the mAb 9B6-4 also caused increases in the percentages of Jurkat T cells in the sub-G1 phase of the cell cycle (14.8%) and undergoing apoptosis (21.3%). CONCLUSION Anti-P autoantibodies may play a role in the pathogenesis of lymphopenia or lymphocyte dysfunction in SLE.
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Affiliation(s)
- K H Sun
- Faculty of Medical Technology and Institute of Biotechnology in Medicine, National Yang-Ming University, Taipei, Taiwan
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Abstract
p55Cdc/Cdc20 is expressed in cycling mammalian cells and has been shown to be an activator of the mitotic spindle assembly checkpoint. We previously showed that overexpression of p55Cdc/Cdc20 in myeloid cells resulted in accelerated apoptosis and inhibition of granulocyte differentiation in the murine myeloid cell line 32Dcl3. p55Cdc/Cdc20 protein expression is detected in cells at late G1 phase of the cell cycle but is maximal during G2 phase. We report in this paper that inducible expression of p55Cdc/Cdc20 in 32Dcl3 cells results in premature transition from G1 to S phase. To characterize the mechanism of this early transition, we examined the expression of critical regulatory proteins during the cell cycle. Although expression of cyclin D, cyclin E, cdk2, and cdc2 did not change significantly between p55Cdc/Cdc20-overexpressing and control cells, p27Kip1 protein levels were lower and cdk2 activity higher during G1 to S transition in p55Cdc/Cdc20-overexpressing cells compared to control cells. Cyclin B1 levels were lower at early G1 phase in cells overexpressing p55Cdc/Cdc20. Our results suggest that p55Cdc/Cdc20 may play an important role in G1 to S transition during myelopoiesis.
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Affiliation(s)
- M L Lin
- Department of Pediatrics, UCLA School of Medicine, Los Angeles, California 90095-1752, USA
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42
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Abstract
The majority of cases involving fragile X syndrome are due to expansion of a (CGG)n trinucleotide repeat at the 5' untranslated region of the FMR-1 gene. Deletion and intragenic loss of function mutations of the FMR-1 gene also have been reported. Here, we report a C to T point mutation at the 14th nucleotide in intron 10 of the FMR-1 gene in three unrelated fragile X patients. However, the (CGG)n repeat of FMR-1 in those patients does not expand. To determine the effect of this mutation on the patients' FMR-1 transcripts, total RNA from peripheral blood cells was reverse transcribed and amplified by polymerase chain reaction (RT-PCR). Direct and subcloned sequencing of the RT-PCR products revealed that the transcripts from the allele with C to T mutation skip exon 10 entirely, resulting in a joining of exons 9 and 11. Deletion of exon 10 results in frame-shift and premature termination of translation, which removes the highly conserved region that encoding the KH2 and RGG box domains of FMRP. Interestingly, a male of the three patients has another G to A substitution in exon 15. However, the intron 10 mutation is sufficient for development of fragile X syndrome.
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Affiliation(s)
- Y C Wang
- Molecular Genetics and Cytogenetics Laboratory, Chung Shan Medical and Dental College, Taichung, Taiwan
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Wang FD, Lin ML, Liu CY. In vitro activity of quinupristin/dalfopristin against gram-positive bacteria Haemophilus influenzae and Branhamella catarrhalis in Taiwan. Zhonghua Yi Xue Za Zhi (Taipei) 2000; 63:433-9. [PMID: 10925532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
BACKGROUND Over the past decade, resistance of Gram-positive cocci to common antibiotics has steadily increased. New antibacterial agents that are active against multidrug-resistant pathogens are urgently needed for the treatment of these pathogens. We conducted an in vitro study on the activity of quinupristin/dalfopristin and other antibiotics against common clinical isolates of the gram-positive cocci, Haemophilus influenzae and Branhamella catarrhalis. METHODS The agar dilution method described by the National Committee for Clinical Laboratory Standards was used to determine the minimum inhibitory concentrations (MICs) of bacterial isolates from clinical specimens obtained from patients in a medical center. RESULTS All Staphylococcus aureus isolates were inhibited by quinupristin/dalfopristin (< or = 2 micrograms/ml). The MIC90s were 1 mg/ml for both methicillin-sensitive and -resistant S aureus. Quinupristin/dalfopristin inhibited streptococci at a concentration of 1 microgram/ml or less. The MIC90s were 1 microgram/ml for Streptococcus pneumoniae, S pyogenes and viridans streptococci. Ampicillin-resistant Enterococcus faecium was inhibited by quinupristin/dalfopristin at 0.5 to 4 micrograms/ml, with an MIC90 of 1 microgram/ml. H influenzae was inhibited by quinupristin/dalfopristin at 0.25 to 8 micrograms/ml, with an MIC90 of 4 micrograms/ml. B catarrhalis was inhibited by quinupristin/dalfopristin at 0.25 to 1 microgram/ml, with an MIC90 of 1 microgram/ml. CONCLUSIONS We found that quinupristin/dalfopristin showed good in vitro activity against staphylococci, streptococci and B catarrhalis but less in vitro activity against H influenzae.
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Affiliation(s)
- F D Wang
- Department of Medicine, Taipei Veterans General Hospital, Taiwan, ROC
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Wang YC, Li C, Lin ML, Lin WH, Li SY. Molecular diagnosis of fragile X syndrome and distribution of CGG repeats in the FMR-1 gene in Taiwanese. J Formos Med Assoc 2000; 99:402-7. [PMID: 10870330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND AND PURPOSE Fragile X syndrome, the most frequent form of inherited mental retardation, is caused by abnormal expansion of the CGG trinucleotide repeats in the 5' untranslated region of the FMR-1 gene. In this study, we describe the prenatal diagnosis of fragile X syndrome and the distribution of CGG repeat numbers in the FMR-1 gene, which has not been previously reported in Taiwanese. METHODS Using polymerase chain reaction (PCR), we determined the range of the CGG repeats in the FMR-1 gene in 316 normal individuals (350 X chromosomes) and 349 mentally retarded patients (429 X chromosomes). For prenatal diagnosis of fragile X syndrome, DNA extracted from amniotic fluid cells was used for PCR determination of CGG repeats. RESULTS Because there were no significant differences between the distribution of the (CGG)n alleles between the mentally retarded and normal subjects, the data were pooled. Among the 779 X chromosomes studied, 24 different alleles were identified with a low of 16 and a high of 45 CGG repeats. The 29 repeat allele was the most common, followed by the 30 and the 28 repeat alleles. We effectively amplified slightly expanded premutation alleles of up to about 90 CGG repeats. In the prenatally diagnosed fetus, a normal 29 repeat allele was found. CONCLUSIONS Determination of the distribution of the CGG repeats in the FMR-1 gene in Taiwanese is useful in genetic counseling regarding fragile X syndrome. Prenatal molecular diagnosis of the syndrome can be successfully performed using amniotic fluid cells.
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Affiliation(s)
- Y C Wang
- Department of Life Sciences, Chung Shan Medical and Dental College, Taichung, Taiwan
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Hsieh M, Li SY, Chen YY, Tsai CJ, Lin ML, Li C, Wu MJ. A non-radioactive polymerase chain reaction method for diagnosis of Machado-Joseph disease. J Formos Med Assoc 1999; 98:705-7. [PMID: 10575843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Machado-Joseph disease (MJD)/spinocerebellar ataxia type 3 (SCA3) is caused by unstable CAG trinucleotide repeat expansion in the coding region of the MJD gene. In this study, we describe a non-radioactive polymerase chain reaction (PCR) method to detect the CAG repeat range of the MJD gene. This technique allows direct visualization of the PCR products on ethidium bromide-stained agarose gels within hours. In this study, genomic DNA samples isolated from peripheral lymphocytes, amniotic fluid cells, and chorionic villi were tested with two sets of commonly used MJD primers. PCR conditions were optimized, which resulted in clear visualization of both the primer sets on 3% agarose gels. Ten out of 25 candidate MJD patients have been identified with this method to date, with no false-positive or false-negative diagnoses. This simple, reliable, and cost-effective method can be used for patient diagnosis, pre-symptomatic diagnosis, and prenatal diagnosis.
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Affiliation(s)
- M Hsieh
- Institute of Medicine, Chung Shan Medical and Dental College, Taichung, Taiwan
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Li J, Lin ML, Wiepz GJ, Guadarrama AG, Bertics PJ. Integrin-mediated migration of murine B82L fibroblasts is dependent on the expression of an intact epidermal growth factor receptor. J Biol Chem 1999; 274:11209-19. [PMID: 10196208 DOI: 10.1074/jbc.274.16.11209] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To evaluate the mechanisms by which epidermal growth factor (EGF) regulates actin-based cellular processes such as cell migration, we first examined the effects of EGF on cell adhesion, which is essential for cell migration. In mouse B82L fibroblasts transfected with the full-length EGF receptor, EGF promotes cell rounding and attenuates cell spreading on fibronectin, laminin, and vitronectin, and thus appears to reduce the strength of cell adhesion. Moreover, EGF synergizes with multiple extracellular matrix (ECM) components in the promotion of integrin-mediated cell migration of several different cell types, including fibroblasts and various carcinoma and osteosarcoma cell lines. Interestingly, co-presentation (co-positioning) of EGF with laminin or fibronectin is essential for EGF-stimulated migration. When EGF is mixed with the cells instead of the ECM components, it has little effect on cell migration. These results suggest that co-presentation of EGF with ECM components can enhance the polarization events required for directional cell movement. To identify the EGF receptor elements critical for the EGF stimulation of cell migration, B82L fibroblasts were transfected with either mutated or wild-type EGF receptors. Surprisingly, we found that B82L-Parental cells that lack the EGF receptor are not able to migrate to fibronectin, even though they can adhere to fibronectin. However, the introduction of wild-type EGF receptors into these fibroblasts enables them to migrate toward fibronectin even in the absence of EGF. The requirement of the EGF receptor for cell migration does not appear to result from the secretion of EGF or TGF-alpha by the cells transfected with the EGF receptor. Furthermore, cells expressing EGF receptors that are kinase-inactive, or C-terminally truncated, exhibit little migration toward fibronectin, indicating that an intact EGF receptor kinase is required for fibronectin-induced cell migration. In addition, neutralizing anti-EGF receptor antibodies attenuate cell migration in the presence of EGF, and inhibit migration to fibronectin or laminin alone. These results further suggest that the EGF receptor is downstream of integrin activation in the signal transduction pathways leading to fibroblast migration.
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Affiliation(s)
- J Li
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin 53706-1532, USA
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Pang WW, Mok MS, Lin ML, Chang DP, Hwang MH. Application of spinal pain mapping in the diagnosis of low back pain--analysis of 104 cases. Acta Anaesthesiol Sin 1998; 36:71-4. [PMID: 9816715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
BACKGROUND Low back pain is probably the most common pain problem seen in a general pain clinic and the cause of low back pain can be enigmatic at times. Often the pain sources are difficult to identify with the conventional diagnostic modalities. Spinal pain mapping is a sequence of well organized nerve block procedures. We undertook this study to evaluate the usefulness of this modality in diagnosing low back pain of uncertain etiology. METHODS In this prospective study, 104 consecutive adult patients who underwent spinal pain mapping were examined and analyzed. All patients had intractable low back pain of undetermined etiology after medical history, physical examination and 4-view roentgenographic evaluation of the lumbar spine had been undertaken to locate it. In addition, 41 patients (39%) had one or more of the following tests done, which included CT, MRI, EMG/NC but all failed to delineate the causes of the pain. All patients failed to respond to the conservative therapies. RESULTS With pain mapping the source of pain was found to be caused by sacro-iliac joint in 6%, lumbar nerve root in 20%, facet joint in 24%, combined lumbar nerve root and facet disease in 24%, internal disc disorder in 7%, combined facet and sacro-iliac joint in 4% and lumbar sympathetic dystrophy in 2% of patients. Pain mapping failed to demonstrate the causes of the pain in the remaining 13% of the patients. CONCLUSIONS Considering the difficult nature of this group of patients, spinal pain mapping provided a useful functional approach to the diagnosis of low back pain with obscure etiology in 87% of patients in our series.
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Affiliation(s)
- W W Pang
- Department of Anesthesia, Show-Chwan Memorial Hospital, Changhua, Taiwan, R.O.C
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Lin ML, Radwin RG. Validation of a frequency-weighted filter for continuous biomechanical stress in repetitive wrist flexion tasks against a load. Ergonomics 1998; 41:476-484. [PMID: 9557588 DOI: 10.1080/001401398186955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This experiment validates a frequency-weighted filter for continuous measurements of force, posture and repetition using a stimulated industrial task. A peg transfer task was used requiring subjects to repetitively insert pegs into holes with controlled resistance. Ten subjects performed the task for six conditions. All wrist flexion angular data were recorded continually using an electrogoniometer and processed through the filter. Subjective discomfort was reported after performing the task for 1 h using a 10 cm visual analogue scale. Results from linear regression analysis showed that the instrument reliably estimated subjective discomfort (r2 = 0.873). Applications and limitations of this instrument are explored.
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Affiliation(s)
- M L Lin
- Department of Industrial Engineering, University of Wisconsin-Madison 53706, USA
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Lin ML, Radwin RG. Agreement between a frequency-weighted filter for continuous biomechanical measurements of repetitive wrist flexion against a load and published psychophysical data. Ergonomics 1998; 41:459-475. [PMID: 9557587 DOI: 10.1080/001401398186946] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A previous pilot study demonstrated that a force and frequency-weighted filter network could be developed for processing continuous biomechanical measures of repetitive wrist motions and exertions. The current study achieves the objective by modelling subjective discomfort for repetitive wrist flexion using controlled posture, pace and force. A three-level fractional factorial experiment was conducted involving repetitive wrist flexion (2 s/motion, 6 s/motion, 10 s/motion) from a neutral posture to a given angle (10 degrees, 28 degrees, 45 degrees) against a controlled resistance (5 N, 25 N, 50 N) using a Box Behnken design. Ten subjects participated. Discomfort was reported on a 10 cm visual analogue scale. Results of response surface regression analysis revealed that main effects of force, wrist flexion angle, and repetition were all significant (p < 0.05) and that no second-order effects were observed. Linear regression analysis on these factors established a discomfort model on which the filter characteristics were based. The pure error test model revealed no significant lack of fit (p > 0.05). The continuous model was compared and agreed with discrete psychophysical data from other published studies. The model was used for generating parameters for a force and frequency-weighted digital filter that weighs continuous wrist postural signals with corresponding force in proportion to the equal discomfort function as a function of frequency of repetition. These filters will enable integration of large quantities of biomechanical data in field studies.
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Affiliation(s)
- M L Lin
- Department of Industrial Engineering, University of Wisconsin-Madison 53706, USA
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Lin ML, Tsang YM, Hwang SL. Efficacy of a stress management program for patients with hepatocellular carcinoma receiving transcatheter arterial embolization. J Formos Med Assoc 1998; 97:113-7. [PMID: 9509846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Transcatheter arterial embolization (TAE), a common treatment for patients with unresectable hepatocellular carcinoma (HCC), can provoke severe physical discomfort and psychologic stress. The purpose of this study was to investigate the effect of a combination of health education, muscle relaxation, and back massage on reducing physical and psychologic stress in HCC patients receiving TAE. A quasi-experimental design was used. Forty patients with HCC (30 men and 10 women) with a mean age of 57 +/- 12 years were recruited and randomly assigned to the control or experimental group. The effectiveness of the stress management program was evaluated using a knowledge questionnaire, a worry inventory, a state-trait anxiety inventory, and a physical distress scale. After completing the stress management program, the experimental group had a greater mean increase in knowledge score than the control group (5.1 vs 0.8, p < 0.0001) and a greater mean decrease in worry score (-8.2 vs 1.1, p < 0.0001). The mean decrease in the anxiety score in the experimental group was also significantly greater than in the control group before TAE (-5.8 vs 3.2, p < 0.001) and 2, 4, 6, and 7 days after TAE (-8.2 vs 7.1, p < 0.001; -8.7 vs 3.2, p < 0.001; -9.8 vs -2.1, p < 0.05; -11 vs -0.9, p < 0.05). The patients in the experimental group had a smaller mean increase in physical distress score than the control group at 2, 4, 6, and 7 days after TAE (34.7 vs 50.2, 20.9 vs 29.6, 10.6 vs 18.2, 3.9 vs 11.2, all p < 0.05). This stress management program effectively reduces the stress of HCC patients undergoing TAE.
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Affiliation(s)
- M L Lin
- Department of Nursing, Taipei Medical College Hospital, Taiwan
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