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Li YW, Chen MN, Dai JY, Zhou Y. Guiding infrared electromagnetic waves through TI nanowires with extremely large wavenumber and azimuthal index. J Phys Condens Matter 2024; 36:275001. [PMID: 38537285 DOI: 10.1088/1361-648x/ad3876] [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] [Received: 02/01/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
In this paper, the dispersion relations of the surface plasmon polaritons (SPPs) in TI nanowires have been investigated. For simplicity, TI nanowire has been modeled as a dielectric cylinder with a conductive surface, the conductivity of which is an anti-symmetric tensor. The off-diagonal terms of the conductivity tensor only slightly change the dispersion relations. Due to small conductivities, these SPPs have extremely large wavenumbers and azimuthal indices; the electric fields are tightly confined near the conductive surface. For high-order modes, cut-off phenomena have been observed. In the end, the effects of losses and much larger bulk permittivities on the dispersion relations of surface plasmons have been discussed. The simple model proposed in this paper can be directly applied to other materials with arbitrary surface conductivity. Our investigations show that TI nanostructures are promising platforms for nanophotonic applications in the future.
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Affiliation(s)
- Y W Li
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - M N Chen
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - J Y Dai
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - Yu Zhou
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
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2
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Li G, Sun Q, Fu Y, Hou S, Zhang J, Xu KL, Dai JY. A single crystal row-column-array for 3D ultrasound imaging. Ultrasonics 2024; 139:107289. [PMID: 38492351 DOI: 10.1016/j.ultras.2024.107289] [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] [Received: 10/01/2023] [Revised: 03/03/2024] [Accepted: 03/03/2024] [Indexed: 03/18/2024]
Abstract
In vivo 3D ultrasound imaging with 2D-array transducers is of great importance for both clinical application and biomedical research, but it is complicated in fabrication and also very expensive in hardware due to thousands of electronic channels. In this work, we demonstrate a new fabrication process of 7-MHz 128 + 128 elements row-column-array (RCA) transducer with relaxor ferroelectric PMN-0.28PT single crystal. With piezoelectric single crystal and improved acoustic matching, the optimized performance of -6 dB bandwidth of ∼82 % and insertion loss of -44.6 dB is achieved. The axial and lateral imaging resolutions at different depth of the RCA transducer are quantified by the point spread function (PSF), and the results are respectively 0.20 mm and 0.41 mm at the depth of 7.7 mm, and 0.22 mm and 0.47 mm at the depth of 16.7 mm. The transducer is validated experimentally on a hyperechoic phantom, and 3D view and slices of B-mode images are obtained. The experimental results indicate that our developed RCA transducer can obtain high-quality 3D ultrasound images, demonstrating great potential on ultrafast 3D and functional imaging.
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Affiliation(s)
- Guo Li
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China; School of Automation, Xi'an University of Posts &Telecommunications, Xi'an, China.
| | - Qiandong Sun
- Department of Biomedical Engineering, Fudan University, Shanghai, China
| | - Yapeng Fu
- Department of Biomedical Engineering, Fudan University, Shanghai, China
| | - Shilin Hou
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jiaming Zhang
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
| | - K L Xu
- Department of Biomedical Engineering, Fudan University, Shanghai, China; Shanghai Poda Medical Technology Co., Ltd., Shanghai, China.
| | - J Y Dai
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
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3
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Wong CM, Chan SF, Liu R, Zhang J, Wu WC, Liang Z, Yau HM, Wang DY, Li S, Lam KH, Qiu WB, Luo HS, Dai JY. 20-MHz phased array ultrasound transducer for in vivo ultrasound imaging of small animals. Ultrasonics 2022; 126:106821. [PMID: 35988512 DOI: 10.1016/j.ultras.2022.106821] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/16/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
In vivo ultrasound imaging with phased array transducers is of great importance for both clinical application and biomedical research. In this work, relaxor ferroelectric PMN-0.28PT single crystal with very high piezoelectric constant d33 ≥ 2000 pC/N and electromechanical coupling coefficient k33 ∼ 0.92 is used to fabricate high-frequency phased array transducers. A 128-element 20-MHz phased array transducer is successfully fabricated, and the optimized performance of -6 dB average bandwidth of ∼ 84 % and insertion loss of -43 dB are achieved. The axial and lateral imaging resolutions of the transducer are determined to be 81 µm and 243 µm, respectively. With Verasonics image platform, in vivo fisheye images are acquired, demonstrating the potential application of our developed high-frequency phased array transducer for biomedical research on small animals.
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Affiliation(s)
- C M Wong
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China; Hospital Authority, Hong Kong, China
| | - S F Chan
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
| | - R Liu
- Shenzhen Key Laboratory of Ultrasound Imaging and Therapy, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - J Zhang
- Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - W C Wu
- Shenzhen Key Laboratory of Ultrasound Imaging and Therapy, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; School of Materials Science and Engineering, The University of New South Wales (UNSW Sydney), Australia
| | - Z Liang
- Shanghai Institute of Ceramics, The Chinese Academy of Sciences, Shanghai, China
| | - H M Yau
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China; Hospital Authority, Hong Kong, China
| | - D Y Wang
- School of Materials Science and Engineering, The University of New South Wales (UNSW Sydney), Australia
| | - S Li
- School of Materials Science and Engineering, The University of New South Wales (UNSW Sydney), Australia
| | - K H Lam
- Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
| | - W B Qiu
- Shenzhen Key Laboratory of Ultrasound Imaging and Therapy, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
| | - H S Luo
- Shanghai Institute of Ceramics, The Chinese Academy of Sciences, Shanghai, China
| | - J Y Dai
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
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4
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Wei C, Zheng KY, Dai JY, Cai HC, Zhu TN, Zhao JL, Zhou DB, Zhuang JL. [The 492nd case: recurrent thrombosis, thrombocytopenia]. Zhonghua Nei Ke Za Zhi 2022; 61:239-242. [PMID: 35090264 DOI: 10.3760/cma.j.cn112138-20210222-00149] [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: 06/14/2023]
Abstract
A 43-year-old female patient was admitted with recurrent thrombosis for more than 2 years and thrombocytopenia for more than 1 year. Both arterial and venous thromboses developed especially at rare sites even during anticoagulation therapy such as cerebral venous sinus thrombosis. Antinuclear antibody, anti-ENA antibody and antiphospholipid antibody were all negative. Platelet count elevated to normal after high dose glucocorticoid and intravenous immunoglobulin (IVIG). Immune thrombocytopenia was suspected. When 4 grade thrombocytopenia recurred, intravenous heparin, rituximab 600 mg, IVIG and eltrombopag were administrated. After 3 weeks, thrombocytopenia did not improve, and new thrombosis developed instead. Screening of thrombophilia related genes revealed PROS1 gene heterozygous mutation and MTHFR TT genotype. Low amount of serum IgG κ monoclonal protein was detected. Heparin-induced thrombocytopenia was differentiated and excluded. Finally, serum negative antiphospholipid syndrome was considered the most likely diagnosis. Dexamethasone 20 mg/day × 4 days combined with sirolimus 2 mg/day was prescribed. The patient was discharged with low molecular weight heparin. At one month, her headache was greatly relieved. The platelet count raised to 20-30×109/L, and no new thrombosis or bleeding was reported.
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Affiliation(s)
- C Wei
- Department of Hematology, Peking Union Medical College Hospital,Peking Union Medical College, Chinese Academy of Medical Sciences,Beijing 100730,China
| | - K Y Zheng
- Department of Internal Medicine, Peking Union Medical College Hospital,Peking Union Medical College, Chinese Academy of Medical Sciences,Beijing 100730, China
| | - J Y Dai
- Department of Emergency, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences,Beijing 100730,China
| | - H C Cai
- Department of Hematology, Peking Union Medical College Hospital,Peking Union Medical College, Chinese Academy of Medical Sciences,Beijing 100730,China
| | - T N Zhu
- Department of Hematology, Peking Union Medical College Hospital,Peking Union Medical College, Chinese Academy of Medical Sciences,Beijing 100730,China
| | - J L Zhao
- Department of Rheumatology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - D B Zhou
- Department of Hematology, Peking Union Medical College Hospital,Peking Union Medical College, Chinese Academy of Medical Sciences,Beijing 100730,China
| | - J L Zhuang
- Department of Hematology, Peking Union Medical College Hospital,Peking Union Medical College, Chinese Academy of Medical Sciences,Beijing 100730,China
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5
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Fang HJ, Chen Y, Wong CM, Qiu WB, Chan HLW, Dai JY, Li Q, Yan QF. Anodic aluminum oxide-epoxy composite acoustic matching layers for ultrasonic transducer application. Ultrasonics 2016; 70:29-33. [PMID: 27125558 DOI: 10.1016/j.ultras.2016.04.003] [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] [Received: 11/30/2015] [Revised: 03/31/2016] [Accepted: 04/03/2016] [Indexed: 06/05/2023]
Abstract
The goal of this work is to demonstrate the application of anodic aluminum oxide (AAO) template as matching layer of ultrasonic transducer. Quarter-wavelength acoustic matching layer is known as a vital component in medical ultrasonic transducers to compensate the acoustic impedance mismatch between piezoelectric element and human body. The AAO matching layer is made of anodic aluminum oxide template filled with epoxy resin, i.e. AAO-epoxy 1-3 composite. Using this composite as the first matching layer, a ∼12MHz ultrasonic transducer based on soft lead zirconate titanate piezoelectric ceramic is fabricated, and pulse-echo measurements show that the transducer exhibits very good performance with broad bandwidth of 68% (-6dB) and two-way insertion loss of -22.7dB. Wire phantom ultrasonic image is also used to evaluate the transducer's performance, and the results confirm the process feasibility and merit of AAO-epoxy composite as a new matching material for ultrasonic transducer application. This matching scheme provides a solution to address the problems existing in the conventional 0-3 composite matching layer and suggests another useful application of AAO template.
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Affiliation(s)
- H J Fang
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; Department of Chemistry, Tsinghua University, Beijing, PR China
| | - Y Chen
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; The Hong Kong Polytechnic University, Shenzhen Research Institute, PR China
| | - C M Wong
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; Department of Electrical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - W B Qiu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - H L W Chan
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - J Y Dai
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; The Hong Kong Polytechnic University, Shenzhen Research Institute, PR China.
| | - Q Li
- Department of Chemistry, Tsinghua University, Beijing, PR China
| | - Q F Yan
- Department of Chemistry, Tsinghua University, Beijing, PR China
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6
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Yau HM, Yan ZB, Chan NY, Au K, Wong CM, Leung CW, Zhang FY, Gao XS, Dai JY. Low-field Switching Four-state Nonvolatile Memory Based on Multiferroic Tunnel Junctions. Sci Rep 2015; 5:12826. [PMID: 26239505 PMCID: PMC4523833 DOI: 10.1038/srep12826] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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: 09/18/2014] [Accepted: 05/20/2015] [Indexed: 11/26/2022] Open
Abstract
Multiferroic tunneling junction based four-state non-volatile memories are very promising for future memory industry since this kind of memories hold the advantages of not only the higher density by scaling down memory cell but also the function of magnetically written and electrically reading. In this work, we demonstrate a success of this four-state memory in a material system of NiFe/BaTiO3/La0.7Sr0.3MnO3 with improved memory characteristics such as lower switching field and larger tunneling magnetoresistance (TMR). Ferroelectric switching induced resistive change memory with OFF/ON ratio of 16 and 0.3% TMR effect have been achieved in this multiferroic tunneling structure.
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Affiliation(s)
- H M Yau
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China
| | - Z B Yan
- Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
| | - N Y Chan
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China
| | - K Au
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China
| | - C M Wong
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China
| | - C W Leung
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China
| | - F Y Zhang
- Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China
| | - X S Gao
- Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China
| | - J Y Dai
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China
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7
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Chen Y, Qiu WB, Lam KH, Liu BQ, Jiang XP, Zheng HR, Luo HS, Chan HLW, Dai JY. Focused intravascular ultrasonic probe using dimpled transducer elements. Ultrasonics 2015; 56:227-231. [PMID: 25108608 DOI: 10.1016/j.ultras.2014.07.011] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 07/09/2014] [Accepted: 07/19/2014] [Indexed: 06/03/2023]
Abstract
High-frequency focused intravascular ultrasonic probes were fabricated in this study using dimple technique based on PMN-PT single crystal and lead-free KNN-KBT-Mn ceramic. The center frequency, bandwidth, and insertion loss of the PMN-PT transducer were 34 MHz, 75%, and 22.9 dB, respectively. For the lead-free probe, the center frequency, bandwidth, and insertion loss were found to be 40 MHz, 72%, and 28.8 dB, respectively. The ultrasonic images of wire phantom and vessels with good resolution were obtained to evaluate the transducer performance. The -6 dB axial and lateral resolutions of the PMN-PT probe were determined to be 58 μm and 131 μm, respectively. For the lead-free probe, the axial and lateral resolutions were found to be 44 μm and 125 μm, respectively. These results suggest that the mechanical dimpling technique has good potential in preparing focused transducers for intravascular ultrasound applications.
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Affiliation(s)
- Y Chen
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China; Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
| | - W B Qiu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - K H Lam
- Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - B Q Liu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - X P Jiang
- Department of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen, China
| | - H R Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - H S Luo
- Information Materials and Devices Research Center, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai, China
| | - H L W Chan
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China; Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
| | - J Y Dai
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China; Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
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8
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Chen Y, Lam KH, Zhou D, Cheng WF, Dai JY, Luo HS, Chan HLW. High frequency PMN-PT single crystal focusing transducer fabricated by a mechanical dimpling technique. Ultrasonics 2013; 53:345-349. [PMID: 22944074 DOI: 10.1016/j.ultras.2012.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 02/04/2012] [Accepted: 06/27/2012] [Indexed: 06/01/2023]
Abstract
High frequency (∼30MHz and ∼80MHz) focusing ultrasound transducers were fabricated using a PMN-0.28PT single crystal by a mechanical dimpling technique. The dimpled single crystal was used as an active element for the focusing transducer. Compared with a plane transducer, the focusing transducer fabricated with a dimpled active element exhibits much broader bandwidth and higher sensitivity. Besides, a high quality image can be obtained by the 30MHz focusing transducer, in which the -6dB axial and lateral resolution is 27μm and 139μm, respectively. These results prove that the dimpling technique is capable to fabricate the high frequency focusing transducers with excellent performance for imaging applications.
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Affiliation(s)
- Y Chen
- Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hunghom, Hong Kong, China.
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9
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Au K, Li DF, Chan NY, Dai JY. Polar liquid molecule induced transport property modulation at LaAlO₃/SrTiO₃ heterointerface. Adv Mater 2012; 24:2598-2602. [PMID: 22495936 DOI: 10.1002/adma.201200673] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Indexed: 05/31/2023]
Affiliation(s)
- K Au
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China
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10
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Chen L, Zhang GL, Jin DZ, Yang L, Dai JY. Influence of discharge gap on the discharge stability in a short vacuum arc ion source. Rev Sci Instrum 2012; 83:02A509. [PMID: 22380205 DOI: 10.1063/1.3673008] [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: 05/31/2023]
Abstract
The influence of the discharge gap between cathode and anode on the discharge stability in a short vacuum arc (SVA) ion source is presented in this paper. Planar cathode and cylindrical hollow anode made of titanium are investigated. There is a great need in present accelerator injection research for SVA source to produce the small deviation of the ion current beam. Current research shows that increasing the short discharge gap can reduce the level of ion current deviation and ion charge deviation from 29% and 31% to 15% and 17%, respectively. A microplasma plume generation mechanism in SVA and scanning electron microscopic results can be used to explain this interesting phenomenon.
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Affiliation(s)
- L Chen
- Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China.
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Lam KH, Chen Y, Cheung KF, Dai JY. PMN-PT single crystal focusing transducer fabricated using a mechanical dimpling technique. Ultrasonics 2012; 52:20-4. [PMID: 21705037 DOI: 10.1016/j.ultras.2011.06.004] [Citation(s) in RCA: 10] [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] [Received: 01/03/2011] [Revised: 04/29/2011] [Accepted: 06/07/2011] [Indexed: 05/20/2023]
Abstract
A ∼5MHz focusing PMN-PT single crystal ultrasound transducer has been fabricated utilizing a mechanical dimpling technique, where the dimpled crystal wafer was used as an active element of the focusing transducer. For the dimpled focusing transducer, the effective electromechanical coupling coefficient was enhanced significantly from 0.42 to 0.56. The dimpled transducer also yields a -6dB bandwidth of 63.5% which is almost double the bandwidth of the plane transducer. An insertion loss of the dimpled transducer (-18.1dB) is much lower than that of the plane transducer. Finite element simulation also reveals specific focused beam from concave crystal surface. These promising results show that the dimpling technique can be used to develop high-resolution focusing single crystal transducers.
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Affiliation(s)
- K H Lam
- Department of Applied Physics, The Hong Kong Polytechnic University, Hunghom, Hong Kong, PR China.
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Huang W, Zeng HZ, Zhu J, Hao JH, Dai JY. Effect of strain on ferroelectric and magnetic behavior in Pb(Zr0.52Ti0.48)O3-based magnetoelectric heterostructures. J Nanosci Nanotechnol 2011; 11:11227-11230. [PMID: 22409090 DOI: 10.1166/jnn.2011.4001] [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: 05/31/2023]
Abstract
In this paper, the "sandwich" structured magnetoelectric composite films of Pb(Zr0.52Ti0.48)O3/ NiFe2O4/Pb(Zr0.52Ti0.48)O3 and Pb(Zr0.52Ti0.48)O3/CoFe2O4/Pb(Zr0.52Ti0.48)O3 are epitaxially grown on SrRuO3/SrTiO3 substrates by pulsed-laser deposition. The crystalline quality and microstructures of these heterostructures are investigated by X-ray diffraction technique. The effects of strain on the ferroelectric, magnetic and magnetoelectric coupling properties of these thin films are systematically studied. The results show that the strain effect induced by lattice mismatch between the ferroelectric/ferromagnetic layers plays an important role in the ferroelectric and magnetic properties of these composite films. Compared to the strained Pb(Zr0.52Ti0.48)O3/ CoFe2O4/Pb(Zr0.52Ti0.48)O3 heterostructure, improved ferroelectric properties with an out-of-plane polarization (2P(r)) of 34.2 microC/cm2 and electric coercivity field of 158 kV/cm are obtained in the strain-free Pb(Zr0.52Ti0.48)O3/NiFe2O4/Pb(Zr0.52Ti0.48)O3 heterostructure. The ME measurement results not only show that the strain induced by lattice mismatch has great influence on the ME behavior, but also provide an understanding of the multilayers with full control over the interface structure at the atomic-scale.
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Affiliation(s)
- W Huang
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronics Science and Technology of China, Chengdu 610054, China
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13
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Abstract
AbstractThe effect of a small amount of Pt (5 at.%) on the thermal stability of NiSi film on (100)Si and (111 )Si has been investigated. Rutherford back scattering, Scanning Electron Microscopy, and X-ray diffraction have been used to study the formation, microstructure and orientation of the silicide. The addition of platinum results in increasing the disilicide nucleation temperature to 900°C and thus leads to a better stability of NiSi at high IC processing temperatures. The presence of Pt also induced a texture of the NiSi film both on (11 1)Si and (100)Si. The increase in thermal stability is explained in terms of nucleation controlled reaction concept and should open new possibilities for the use of NiSi in self aligned silicidation. The redistribution of Pt in the silicide is examined and explained in terms of kinetics and thermodynamics considerations. The addition of Pt also increases the temperature of agglomeration of NiSi.
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14
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Zhang XY, Dai JY, Ong HC. Hydrothermal Synthesis and Properties of Diluted Magnetic Semiconductor Zn<sub>1-x</sub>Mn<sub>x</sub>O Nanowires. ACTA ACUST UNITED AC 2011. [DOI: 10.4236/ojpc.2011.11002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Abstract
The memory effects of gold (Au) nanocrystal (NC) non-volatile memory structures consisting of polyvinylpyrrolidone (PVP) K-30 polymer tunneling and control layers are investigated. The trilayer structure (PV P/Au-NCs + PV P/PV P) on p-type Si substrate was fabricated by spin coating, and transmission electron microscopy study reveals that the average size of the Au-NCs formed is about 5 nm in diameter. Capacitance-voltage (C-V) measurement on the memory structure shows a counter-clockwise hysteresis loop with a significant flat band voltage shift, revealing a memory effect of the Au-NCs with a charge density of up to 1 x 10(12) cm(-2) and a flat band voltage shift of 2.0 V. A unique feature of the double loop in the C-V curves suggests double barriers during electron tunneling. The I-V hysteresis is also characterized, and a switching mechanism of resistive change is discussed.
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Affiliation(s)
- P F Lee
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China
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16
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Lau ST, Li H, Wong KS, Zhou QF, Zhou D, Li YC, Luo HS, Shung KK, Dai JY. Multiple matching scheme for broadband 0.72Pb(Mg(13)Nb(23))O(3)-0.28PbTiO(3) single crystal phased-array transducer. J Appl Phys 2009; 105:94908. [PMID: 19657405 PMCID: PMC2719468 DOI: 10.1063/1.3065476] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Accepted: 11/25/2008] [Indexed: 05/18/2023]
Abstract
Lead magnesium niobate-lead titanate single crystal 0.72Pb(Mg(13)Nb(23))O(3)-0.28PbTiO(3) (abbreviated as PMN-PT) was used to fabricate high performance ultrasonic phased-array transducer as it exhibited excellent piezoelectric properties. In this paper, we focus on the design and fabrication of a low-loss and wide-band transducer for medical imaging applications. A KLM model based simulation software PiezoCAD was used for acoustic design of the transducer including the front-face matching and backing. The calculated results show that the -6 dB transducer bandwidth can be improved significantly by using double lambda8 matching layers and hard backing. A 4.0 MHz PMN-PT transducer array (with 16 elements) was fabricated and tested in a pulse-echo arrangement. A -6 dB bandwidth of 110% and two-way insertion loss of -46.5 dB were achieved.
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Tsang MB, Lee J, Su SC, Dai JY, Horoi M, Liu H, Lynch WG, Warren S. Survey of excited state neutron spectroscopic factors for Z=8-28 nuclei. Phys Rev Lett 2009; 102:062501. [PMID: 19257580 DOI: 10.1103/physrevlett.102.062501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Indexed: 05/27/2023]
Abstract
We have extracted 565 neutron spectroscopic factors of sd and fp shell nuclei by systematically analyzing more than 2000 measured (d, p) angular distributions. We are able to compare 125 of the extracted spectroscopic factors to values predicted by large-basis shell-model calculations and evaluate the accuracies of spectroscopic factors predicted by different shell-model interactions in these regions. We find that the spectroscopic factors predicted for most excited states of sd-shell nuclei using the latest USDA or USDB interactions agree with the experimental values. For fp shell nuclei, the inability of the current models to account for the core excitation and fragmentation of the states leads to considerable discrepancies. In particular, the agreement between data and shell-model predictions for Ni isotopes is not better than a factor of 2 using either the GXPF1A or the XT interaction.
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Affiliation(s)
- M B Tsang
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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Chakraborty G, Sarkar CK, Lu XB, Dai JY. Study of the tunnelling initiated leakage current through the carbon nanotube embedded gate oxide in metal oxide semiconductor structures. Nanotechnology 2008; 19:255401. [PMID: 21828650 DOI: 10.1088/0957-4484/19/25/255401] [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: 05/31/2023]
Abstract
The tunnelling currents through the gate dielectric partly embedded with semiconducting single-wall carbon nanotubes in a silicon metal-oxide-semiconductor (MOS) structure have been investigated. The application of the gate voltage to such an MOS device results in the band bending at the interface of the partly embedded oxide dielectric and the surface of the silicon, initiating tunnelling through the gate oxide responsible for the gate leakage current whenever the thickness of the oxide is scaled. A model for silicon MOS structures, where carbon nanotubes are confined in a narrow layer embedded in the gate dielectric, is proposed to investigate the direct and the Fowler-Nordheim (FN) tunnelling currents of such systems. The idea of embedding such elements in the gate oxide is to assess the possibility for charge storage for memory device applications. Comparing the FN tunnelling onset voltage between the pure gate oxide and the gate oxide embedded with carbon nanotubes, it is found that the onset voltage decreases with the introduction of the nanotubes. The direct tunnelling current has also been studied at very low gate bias, for the thin oxide MOS structure which plays an important role in scaling down the MOS transistors. The FN tunnelling current has also been studied with varying nanotube diameter.
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Affiliation(s)
- Gargi Chakraborty
- Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata, India
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19
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Wang S, Liu W, Zhang M, Song Z, Lin C, Dai JY, Lee PF, Chan HLW, Choy CL. Negative photoconductivity and memory effects of germanium nanocrystals embedded in HfO2 dielectric. J Nanosci Nanotechnol 2006; 6:205-8. [PMID: 16578903] [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: 05/08/2023]
Abstract
A metal-insulator-semiconductor (MIS) structure containing an HfO2/SiO2 stack tunnel layer, isolated Germanium (Ge) nanocrystals, and an HfO2 capping layer, was obtained by an electron-beam evaporation method. A high-resolution transmission electron microscopy (HRTEM) study revealed that uniform and pronounced Ge nanocrystals had formed after annealing. Raman spectroscopy provided evidence for the formation of Ge-Ge bonds and the optimal annealing temperature for the crystallization ratio of the Ge. The electric properties of the MIS structure were characterized by capacitance-voltage (C-V) and current-voltage (I-V) measurements at room temperature. Negative photoconductivity was observed when the structure was under a forward bias, which screened the bias voltage, resulting in a decrease in the current at a given voltage and a negative shift in flat band voltage. A relatively high stored charge density of 3.27 x 10(12) cm 2 was also achieved.
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Affiliation(s)
- Shiye Wang
- The Research Center of Semiconductor Functional Film Engineering Technology, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, PR China
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Tang DP, Yuan R, Chai YQ, Zhong X, Liu Y, Dai JY, Zhang LY. Novel potentiometric immunosensor for hepatitis B surface antigen using a gold nanoparticle-based biomolecular immobilization method. Anal Biochem 2004; 333:345-50. [PMID: 15450811 DOI: 10.1016/j.ab.2004.06.035] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [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: 05/05/2004] [Indexed: 11/23/2022]
Abstract
A novel potentiometric immunosensor for the detection of hepatitis B surface antigen has been developed by means of self-assembly to immobilize hepatitis B surface antibody on a platinum disk electrode based on gold nanoparticles, Nafion, and gelatin as matrices in this study. The modification procedure of the immunosensor was further characterized by using cyclic voltammetry and the enzyme-linked immunosorbent assay (ELISA) method. The detection is based on the change in the electric potential before and after the antigen-antibody reaction. In contrast to the commonly applied methods (e.g., the glutaraldehyde crosslinking procedure), this strategy could allow for antibodies immobilized with a higher loading amount and better retained immunoactivity, as demonstrated by the potentiometric measurements. A dynamic concentration range of 4-800 ng ml(-1) and a detection limit of 1.3 ng ml(-1) were observed. Analytical results of several human serum samples obtained using the developing technique are in satisfactory agreement with those given by ELISA. In addition, the technique presents some distinct advantages over the traditional sandwich format in that the analyzing performances are direct, rapid, and simple without multiple separation and labeling steps.
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Affiliation(s)
- D P Tang
- College of Chemistry Chemical Engineering, Southwest Normal University, Chongqing 400715, People's Republic of China
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Gong GL, Cheng GB, Hu JH, Dai JY. [Determination of elemenyl piperidine salt in water by capillary gas chromatography]. Se Pu 2000; 18:335-6. [PMID: 12541511] [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: 02/28/2023] Open
Abstract
beta-Elemene and its derivatives were hopeful new antitumor drugs. A method for determination of elemenyl piperidine salt in water has been developed with capillary gas chromatography. The samples were neutralized by sodium carbonate and extracted by n-heptane. n-Octadecane was used as the internal standard. The linear range was from 10 g/L to 100 g/L, with a correlation coefficient of 0.9998. The average recovery of the method was 99.96% and the RSD was 0.46% (n = 5). The coefficient of variation was less than 2%. The method is simple, rapid, accurate and can be applied to the determination of the nitrogen-containing compounds of beta-elemene.
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Affiliation(s)
- G L Gong
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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Jin LJ, Wei Z, Dai JY, Guo P, Wang LS. Prediction of partitioning properties for benzaldehydes by various molecular descriptors. Bull Environ Contam Toxicol 1998; 61:1-7. [PMID: 9657823 DOI: 10.1007/s001289900721] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- L J Jin
- Department of Environmental Science and Engineering, Nanjing University, Peoples' Republic of China
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23
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Dai JY, Li DX, Ye HQ. Direct imaging of O-lattice of interfaces in Ti(CN)-TiB 2-Ni ceramics. Acta Crystallogr A 1993. [DOI: 10.1107/s0108767378091291] [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: 11/10/2022] Open
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Li SW, Sun HL, Lu XJ, Zhang SY, Lu FL, Dai JY, Xu YB. [Synthesis of cephalotaxine esters and their antitumor activity (author's transl)]. Yao Xue Xue Bao 1981; 16:821-7. [PMID: 7342677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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