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Chang WJ, Jang S, Kim M, Kim Y, Jeong DY, Kim B, Kim JM, Nam S, Park WI. MoS 2 Passivated Multilayer Graphene Membranes for Li-Ion Extraction From Seawater. Small 2023; 19:e2207020. [PMID: 36642853 DOI: 10.1002/smll.202207020] [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: 11/11/2022] [Revised: 12/14/2022] [Indexed: 05/04/2023]
Abstract
Abundant Li resources in the ocean are promising alternatives to refining ore, whose supplies are limited by the total amount and geopolitical imbalance of reserves in Earth's crust. Despite advances in Li+ extraction using porous membranes, they require screening other cations on a large scale due to the lack in precise control of pore size and inborn defects. Herein, MoS2 nanoflakes on a multilayer graphene membrane (MFs-on-MGM) that possess ion channels comprising i) van der Waals interlayer gaps for optimal Li+ extraction and ii) negatively charged vertical inlets for cation attraction, are reported. Ion transport measurements across the membrane reveal ≈6- and 13-fold higher selectivity for Li+ compared to Na+ and Mg2+ , respectively. Furthermore, continuous, stable Li+ extraction from seawater is demonstrated by integrating the membrane into a H2 and Cl2 evolution system, enabling more than 104 -fold decrease in the Na+ concentration and near-complete elimination of other cations.
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Affiliation(s)
- Won Jun Chang
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Suhee Jang
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Minjoo Kim
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Yelim Kim
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Dae Yeop Jeong
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Beomju Kim
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Jin Myung Kim
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
| | - SungWoo Nam
- Department of Mechanical and Aerospace Engineering, Samueli School of Engineering, University of California Irvine, Irvine, CA, 92697, USA
| | - Won Il Park
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, Republic of Korea
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Lee JH, Chang WJ, Choi WY, Park JM, Jang JI, Park WI. Direct nanofluidic channels via hardening and wrinkling of thin polymer films. Nanoscale 2020; 12:16895-16900. [PMID: 32766647 DOI: 10.1039/d0nr04032k] [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: 06/11/2023]
Abstract
In this study, we propose a rational route to create wrinkling patterns with individually controllable location and direction in thin polymer films. Optical and atomic force microscopy analysis confirmed the formation of straight wrinkles with a typical width of 1.51 to 1.55 μm and a height of 60 to 65 nm. Confocal fluorescence microscopy revealed that each wrinkle produces a continuous hollow channel that interconnects neighboring holes in the polymer film, demonstrating potential applications as nanoscale fluidic channel and reactor. Moreover, we propose a mechanism that considers the elastic deformation energy and interface energies as crucial parameters that govern the mechanical instabilities, which provides scaling relationships between the height, width, and thickness of the wrinkles. This offers additional opportunities for control over the size and aspect ratio of the wrinkles and channels.
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Affiliation(s)
- Jae Hyung Lee
- Division of Materials Science and Engineering Hanyang University, Seoul 04763, Republic of Korea.
| | - Won Jun Chang
- Division of Materials Science and Engineering Hanyang University, Seoul 04763, Republic of Korea.
| | - Won Young Choi
- Division of Materials Science and Engineering Hanyang University, Seoul 04763, Republic of Korea.
| | - Jeong-Min Park
- Division of Materials Science and Engineering Hanyang University, Seoul 04763, Republic of Korea.
| | - Jae-Il Jang
- Division of Materials Science and Engineering Hanyang University, Seoul 04763, Republic of Korea.
| | - Won Il Park
- Division of Materials Science and Engineering Hanyang University, Seoul 04763, Republic of Korea.
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Cheon S, Lee WW, Park WI, Jung JY, Choi JH, Choi DG, Jeon S, Jeong JH, Lee J. Fabrication of arrangement-controlled and vertically grown ZnO nanorods by metal nanotransfer printing. J IND ENG CHEM 2020. [DOI: 10.1016/j.jiec.2019.09.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Kim SY, Gill B, Song BG, Chu H, Park WI, Lee HI, Shin EH, Cho SH, Roh JY. Annual Fluctuation in Chigger Mite Populations and Orientia Tsutsugamushi Infections in Scrub Typhus Endemic Regions of South Korea. Osong Public Health Res Perspect 2019; 10:351-358. [PMID: 31897364 PMCID: PMC6927423 DOI: 10.24171/j.phrp.2019.10.6.05] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Objectives Chigger mites are vectors for scrub typhus. This study evaluated the annual fluctuations in chigger mite populations and Orientia tsutsugamushi infections in South Korea. Methods During 2006 and 2007, chigger mites were collected monthly from wild rodents in 4 scrub typhus endemic regions of South Korea. The chigger mites were classified based on morphological characteristics, and analyzed using nested PCR for the detection of Orientia tsutsugamushi. Results During the surveillance period, the overall trapping rate for wild rodents was 10.8%. In total, 17,457 chigger mites (representing 5 genera and 15 species) were collected, and the average chigger index (representing the number of chigger mites per rodent), was 31.7. The monthly chigger index was consistently high (> 30) in Spring (March to April) and Autumn (October to November). The mite species included Leptotrombidium pallidum (43.5%), L. orientale (18.9%), L. scutellare (18.1%), L. palpale (10.6%), and L. zetum (3.6%). L. scutellare and L. palpale populations, were relatively higher in Autumn. Monthly O. tsutsugamushi infection rates in wild rodents (average: 4.8%) and chigger mites (average: 0.7%) peaked in Spring and Autumn. Conclusion The findings demonstrated a bimodal pattern of the incidence of O. tsutsugamushi infections. Higher infection rates were observed in both wild rodents and chigger mites, in Spring and Autumn. However, this did not reflect the unimodal incidence of scrub typhus in Autumn. Further studies are needed to identify factors, such as human behavior and harvesting in Autumn that may explain this discordance.
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Affiliation(s)
- Seong Yoon Kim
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Byoungchul Gill
- Division of Laboratory Diagnosis Management, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Bong Gu Song
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Hyuk Chu
- Division of Bacterial Disease Research, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Won Il Park
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Hee Il Lee
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - E-Hyun Shin
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Shin-Hyeong Cho
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
| | - Jong Yul Roh
- Division of Vectors and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Cheongju, Korea
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Chang WJ, Lee GH, Cheon YJ, Kim JT, Lee SI, Kim J, Kim M, Park WI, Lee YJ. Direct Observation of Carboxymethyl Cellulose and Styrene-Butadiene Rubber Binder Distribution in Practical Graphite Anodes for Li-Ion Batteries. ACS Appl Mater Interfaces 2019; 11:41330-41337. [PMID: 31613086 DOI: 10.1021/acsami.9b13803] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Despite the important role of carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) binders in graphite electrodes for Li-ion batteries, the direct analysis of these binders remains challenging, particularly at very low concentrations as in practical graphite anodes. In this paper, we report the systematic investigation of the physiochemical behavior of the CMC and SBR binders and direct observations of their distributions in practical graphite electrodes. The key to this unprecedented capability is combining the advantages of several analytic techniques, including laser-ablation laser-induced break-down spectroscopy, time of flight secondary ion mass spectrometry, and a surface and interfacial cutting analysis system. By correlating the vertical distribution with the adsorption behaviors of the CMC, our study reveals that the CMC migration toward the surface during the drying process depends on the degree of cross-linked binder-graphite network generation, which is determined by the surface property of graphite and CMC materials. The suggested analytical techniques enable the independent tracing of CMC and SBR, disclosing the different vertical distribution of SBR from that of the CMC binder in our practical graphite anodes. This achievement provides additional opportunity to analyze the correlation between the binder distribution and mechanical properties of the electrodes.
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Affiliation(s)
| | | | | | | | | | - Jaehyuk Kim
- Laboratory of Electrode Development Group , Samsung SDI , Suwon 16419 , Republic of Korea
| | - Myungseop Kim
- Laboratory of Electrode Development Group , Samsung SDI , Suwon 16419 , Republic of Korea
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6
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Kwon SS, Choi J, Heiranian M, Kim Y, Chang WJ, Knapp PM, Wang MC, Kim JM, Aluru NR, Park WI, Nam S. Electrical Double Layer of Supported Atomically Thin Materials. Nano Lett 2019; 19:4588-4593. [PMID: 31203634 DOI: 10.1021/acs.nanolett.9b01563] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The electrical double layer (EDL), consisting of two parallel layers of opposite charges, is foundational to many interfacial phenomena and unique in atomically thin materials. An important but unanswered question is how the "transparency" of atomically thin materials to their substrates influences the formation of the EDL. Here, we report that the EDL of graphene is directly affected by the surface energy of the underlying substrates. Cyclic voltammetry and electrochemical impedance spectroscopy measurements demonstrate that graphene on hydrophobic substrates exhibits an anomalously low EDL capacitance, much lower than what was previously measured for highly oriented pyrolytic graphite, suggesting disturbance of the EDL ("disordered EDL") formation due to the substrate-induced hydrophobicity to graphene. Similarly, electrostatic gating using EDL of graphene field-effect transistors shows much lower transconductance levels or even no gating for graphene on hydrophobic substrates, further supporting our hypothesis. Molecular dynamics simulations show that the EDL structure of graphene on a hydrophobic substrate is disordered, caused by the disruption of water dipole assemblies. Our study advances understanding of EDL in atomically thin limit.
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Affiliation(s)
- Sun Sang Kwon
- Division of Materials Science and Engineering , Hanyang University , Seoul 04763 , Korea
| | - Jonghyun Choi
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Mohammad Heiranian
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Yerim Kim
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Won Jun Chang
- Division of Materials Science and Engineering , Hanyang University , Seoul 04763 , Korea
| | - Peter M Knapp
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Michael Cai Wang
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Jin Myung Kim
- Department of Materials Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Narayana R Aluru
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Won Il Park
- Division of Materials Science and Engineering , Hanyang University , Seoul 04763 , Korea
| | - SungWoo Nam
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Department of Materials Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
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7
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Lee D, Park H, Han SD, Kim SH, Huh W, Lee JY, Kim YS, Park MJ, Park WI, Kang CY, Lee CH. Self-Powered Chemical Sensing Driven by Graphene-Based Photovoltaic Heterojunctions with Chemically Tunable Built-In Potentials. Small 2019; 15:e1804303. [PMID: 30548400 DOI: 10.1002/smll.201804303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/22/2018] [Indexed: 06/09/2023]
Abstract
Ultralow power chemical sensing is essential toward realizing the Internet of Things. However, electrically driven sensors must consume power to generate an electrical readout. Here, a different class of self-powered chemical sensing platform based on unconventional photovoltaic heterojunctions consisting of a top graphene (Gr) layer in contact with underlying photoactive semiconductors including bulk silicon and layered transition metal dichalcogenides is proposed. Owing to the chemically tunable electrochemical potential of Gr, the built-in potential at the junction is effectively modulated by absorbed gas molecules in a predictable manner depending on their redox characteristics. Such ability distinctive from bulk photovoltaic counterparts enables photovoltaic-driven chemical sensing without electric power consumption. Furthermore, it is demonstrated that the hydrogen (H2 ) sensing properties are independent of the light intensity, but sensitive to the gas concentration down to the 1 ppm level at room temperature. These results present an innovative strategy to realize extremely energy-efficient sensors, providing an important advancement for future ubiquitous sensing.
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Affiliation(s)
- Donghun Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Haeli Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Soo Deok Han
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
- Center for Electronic Materials Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Su Han Kim
- Division of Materials of Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Woong Huh
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Jae Yoon Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Yoon Seok Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Myung Jin Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Won Il Park
- Division of Materials of Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Chong-Yun Kang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
- Center for Electronic Materials Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Chul-Ho Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
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Yue C, Liu Z, Chang WJ, Park WI, Song T. Hollow C nanobox: An efficient Ge anode supporting structure applied to high-performance Li ion batteries. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.09.075] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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9
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Lee JH, Lee WW, Yang DW, Chang WJ, Kwon SS, Park WI. Anomalous Photovoltaic Response of Graphene-on-GaN Schottky Photodiodes. ACS Appl Mater Interfaces 2018; 10:14170-14174. [PMID: 29620853 DOI: 10.1021/acsami.8b02043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Graphene has attracted great attention as an alternative to conventional metallic or transparent conducting electrodes. Despite its similarities with conventional electrodes, recent studies have shown that a single-atom layer of graphene possesses unique characteristics, such as a tunable work function and transparencies for electric potential, reactivity, and wetting. Nevertheless, a systematic analysis of graphene and semiconductor junction characteristics has not yet been carried out. Here, we report the photoresponse characteristics of graphene-on-GaN Schottky junction photodiodes (Gr-GaN SJPDs), showing a typical rectifying behavior and distinct photovoltaic and photoelectric responses. Following the initial abrupt response to UV illumination, the Gr-GaN SJPDs exhibited a distinct difference in photocarrier dynamics depending on the applied bias voltage, which is characterized by either a negative or positive change in photocurrent with time. We propose underlying mechanisms for the anomalous photocarrier dynamics based on the interplay between electrostatic molecular interactions over the one-atom-thick graphene and GaN junction and trapped photocarriers at the defect states in the GaN thin film.
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Affiliation(s)
- Jae Hyung Lee
- Division of Materials Science and Engineering , Hanyang University , Seoul 04763 , Republic of Korea
| | - Won Woo Lee
- Division of Materials Science and Engineering , Hanyang University , Seoul 04763 , Republic of Korea
| | - Dong Won Yang
- Division of Materials Science and Engineering , Hanyang University , Seoul 04763 , Republic of Korea
| | - Won Jun Chang
- Division of Materials Science and Engineering , Hanyang University , Seoul 04763 , Republic of Korea
| | - Sun Sang Kwon
- Division of Materials Science and Engineering , Hanyang University , Seoul 04763 , Republic of Korea
| | - Won Il Park
- Division of Materials Science and Engineering , Hanyang University , Seoul 04763 , Republic of Korea
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10
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Kang SB, Won SH, Im MJ, Kim CU, Park WI, Baik JM, Choi KJ. Enhanced piezoresponse of highly aligned electrospun poly(vinylidene fluoride) nanofibers. Nanotechnology 2017; 28:395402. [PMID: 28699921 DOI: 10.1088/1361-6528/aa7f6b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Well-ordered nanostructure arrays with controlled densities can potentially improve material properties; however, their fabrication typically involves the use of complicated processing techniques. In this work, we demonstrate a uniaxial alignment procedure for fabricating poly(vinylidene fluoride) (PVDF) electrospun nanofibers (NFs) by introducing collectors with additional steps. The mechanism of the observed NF alignment, which occurs due to the concentration of lateral electric field lines around collector steps, has been elucidated via finite-difference time-domain simulations. The membranes composed of well-aligned PVDF NFs are characterized by a higher content of the PVDF β-phase, as compared to those manufactured from randomly orientated fibers. The piezoelectric energy harvester, which was fabricated by transferring well-aligned PVDF NFs onto flexible substrates with Ag electrodes attached to both sides, exhibited a 2-fold increase in the output voltage and a 3-fold increase in the output current as compared to the corresponding values obtained for the device manufactured from randomly oriented NFs. The enhanced piezoresponse observed for the aligned PVDF NFs is due to their higher β-phase content, denser structure, smaller effective radius of curvature during bending, greater applied strain, and higher fraction of contributing NFs.
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Affiliation(s)
- Sung Bum Kang
- School of Materials Science and Engineering, KIST-UNIST Ulsan Center for Convergent Materials (KUUC), Ulsan National Institute of Science and Technology (UNIST), Ulsan 44-919, Republic of Korea
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11
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Yi J, Wang Y, Jiang Y, Jung IW, Liu W, De Andrade V, Xu R, Parameswaran R, Peters IR, Divan R, Xiao X, Sun T, Lee Y, Park WI, Tian B. 3D calcite heterostructures for dynamic and deformable mineralized matrices. Nat Commun 2017; 8:509. [PMID: 28894143 PMCID: PMC5593869 DOI: 10.1038/s41467-017-00560-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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: 05/08/2017] [Accepted: 07/10/2017] [Indexed: 12/20/2022] Open
Abstract
Scales are rooted in soft tissues, and are regenerated by specialized cells. The realization of dynamic synthetic analogues with inorganic materials has been a significant challenge, because the abiological regeneration sites that could yield deterministic growth behavior are hard to form. Here we overcome this fundamental hurdle by constructing a mutable and deformable array of three-dimensional calcite heterostructures that are partially locked in silicone. Individual calcite crystals exhibit asymmetrical dumbbell shapes and are prepared by a parallel tectonic approach under ambient conditions. The silicone matrix immobilizes the epitaxial nucleation sites through self-templated cavities, which enables symmetry breaking in reaction dynamics and scalable manipulation of the mineral ensembles. With this platform, we devise several mineral-enabled dynamic surfaces and interfaces. For example, we show that the induced growth of minerals yields localized inorganic adhesion for biological tissue and reversible focal encapsulation for sensitive components in flexible electronics. Minerals are rarely explored as building blocks for dynamic inorganic materials. Here, the authors derive inspiration from fish scales to create mutable surfaces based on arrays of calcite crystals, in which one end of each crystal is immobilized in and regenerated from silicone, and the other functional end is left exposed.
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Affiliation(s)
- Jaeseok Yi
- Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA.,The James Franck Institute, The University of Chicago, Chicago, IL, 60637, USA
| | - Yucai Wang
- The CAS Key Laboratory of Innate Immunity and Chronic Diseases, School of Life Sciences and Medical Center, The University of Science & Technology of China, Hefei, Anhui, 230027, China.
| | - Yuanwen Jiang
- Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA.,The James Franck Institute, The University of Chicago, Chicago, IL, 60637, USA
| | - Il Woong Jung
- The Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Wenjun Liu
- The Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Vincent De Andrade
- The Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Ruqing Xu
- The Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | | | - Ivo R Peters
- The James Franck Institute, The University of Chicago, Chicago, IL, 60637, USA.,Engineering and The Environment, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
| | - Ralu Divan
- The Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Xianghui Xiao
- The Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Tao Sun
- The Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Youjin Lee
- Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA
| | - Won Il Park
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, Korea.
| | - Bozhi Tian
- Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA. .,The James Franck Institute, The University of Chicago, Chicago, IL, 60637, USA. .,The Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, 60637, USA.
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12
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Kwon SS, Shin JH, Choi J, Nam S, Park WI. Defect-Mediated Molecular Interaction and Charge Transfer in Graphene Mesh-Glucose Sensors. ACS Appl Mater Interfaces 2017; 9:14216-14221. [PMID: 28374989 DOI: 10.1021/acsami.7b00848] [Citation(s) in RCA: 9] [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: 06/07/2023]
Abstract
We report the role of defects in enzymatic graphene field-effect transistor sensors by introducing engineered defects in graphene channels. Compared with conventional graphene sensors (Gr sensors), graphene mesh sensors (GM sensors), with an array of circular holes, initially exhibited a higher irreversible response to glucose, involving strong chemisorption to edge defects. However, after immobilization of glucose oxidase, the irreversibility of the responses was substantially diminished, without any reduction in the sensitivity of the GM sensors (i.e., -0.53 mV/mM for the GM sensor vs -0.37 mV/mM for Gr sensor). Furthermore, multiple cycle operation led to rapid sensing and improved the reversibility of GM sensors. In addition, control tests with sensors containing a linker showed that sensitivity was increased in Gr sensors but decreased in GM sensors. Our findings indicate that edge defects can be used to replace linkers for immobilization of glucose oxidase and improve charge transfer across glucose oxidase-graphene interfaces.
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Affiliation(s)
- Sun Sang Kwon
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
| | - Jae Hyeok Shin
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
| | - Jonghyun Choi
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - SungWoo Nam
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Won Il Park
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
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Hwang MS, Kim HR, Kim KH, Jeong KY, Park JS, Choi JH, Kang JH, Lee JM, Park WI, Song JH, Seo MK, Park HG. Switching of Photonic Crystal Lasers by Graphene. Nano Lett 2017; 17:1892-1898. [PMID: 28165745 DOI: 10.1021/acs.nanolett.6b05207] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Unique features of graphene have motivated the development of graphene-integrated photonic devices. In particular, the electrical tunability of graphene loss enables high-speed modulation of light and tuning of cavity resonances in graphene-integrated waveguides and cavities. However, efficient control of light emission such as lasing, using graphene, remains a challenge. In this work, we demonstrate on/off switching of single- and double-cavity photonic crystal lasers by electrical gating of a monolayer graphene sheet on top of photonic crystal cavities. The optical loss of graphene was controlled by varying the gate voltage Vg, with the ion gel atop the graphene sheet. First, the fundamental properties of graphene were investigated through the transmittance measurement and numerical simulations. Next, optically pumped lasing was demonstrated for a graphene-integrated single photonic crystal cavity at Vg below -0.6 V, exhibiting a low lasing threshold of ∼480 μW, whereas lasing was not observed at Vg above -0.6 V owing to the intrinsic optical loss of graphene. Changing quality factor of the graphene-integrated photonic crystal cavity enables or disables the lasing operation. Moreover, in the double-cavity photonic crystal lasers with graphene, switching of individual cavities with separate graphene sheets was achieved, and these two lasing actions were controlled independently despite the close distance of ∼2.2 μm between adjacent cavities. We believe that our simple and practical approach for switching in graphene-integrated active photonic devices will pave the way toward designing high-contrast and ultracompact photonic integrated circuits.
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Affiliation(s)
- Min-Soo Hwang
- Department of Physics, Korea University , Seoul 02842, Republic of Korea
| | - Ha-Reem Kim
- Department of Physics, Korea University , Seoul 02842, Republic of Korea
| | - Kyoung-Ho Kim
- Department of Physics, Korea University , Seoul 02842, Republic of Korea
| | - Kwang-Yong Jeong
- Department of Physics, Korea University , Seoul 02842, Republic of Korea
| | - Jin-Sung Park
- Department of Physics, Korea University , Seoul 02842, Republic of Korea
| | - Jae-Hyuck Choi
- Department of Physics, Korea University , Seoul 02842, Republic of Korea
| | - Ju-Hyung Kang
- Department of Physics, Korea University , Seoul 02842, Republic of Korea
| | - Jung Min Lee
- Department of Physics, Korea University , Seoul 02842, Republic of Korea
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Republic of Korea
| | - Won Il Park
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Republic of Korea
| | - Jung-Hwan Song
- Department of Physics and Institute for the NanoCentury, KAIST , Daejeon 34141, Republic of Korea
| | - Min-Kyo Seo
- Department of Physics and Institute for the NanoCentury, KAIST , Daejeon 34141, Republic of Korea
| | - Hong-Gyu Park
- Department of Physics, Korea University , Seoul 02842, Republic of Korea
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15
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Yuk JS, Ji HY, Lee JH, Park WI. Graves' Disease Is Associated With Endometriosis: 3-Year Population-Based Study. J Minim Invasive Gynecol 2016; 22:S29. [PMID: 27679196 DOI: 10.1016/j.jmig.2015.08.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- J-S Yuk
- Obstetrics and Gynecology, MizMedi Hospital, School of Medicine, Eulji University, Seoul, Korea
| | - H-Y Ji
- Obstetrics and Gynecology, MizMedi Hospital, Seoul, Korea
| | - J H Lee
- Obstetrics and Gynecology, MizMedi Hospital, School of Medicine, Eulji University, Seoul, Korea
| | - W I Park
- Obstetrics and Gynecology, School of Medicine, Eulji University, Daejeon, Korea
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16
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Park KS, Lee KS, Baek J, Lee L, Son BH, Koo Lee YE, Ahn YH, Park WI, Kang Y, Sung MM. Observation of Charge Separation and Space-Charge Region in Single-Crystal P3HT/C60
Heterojunction Nanowires. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201603961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Kyung Sun Park
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Ki Seok Lee
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Jangmi Baek
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Lynn Lee
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Byung Hee Son
- Department of Physics; Ajou University; Suwon 16499 South Korea
| | - Yong-Eun Koo Lee
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Yeong Hwan Ahn
- Department of Physics; Ajou University; Suwon 16499 South Korea
| | - Won Il Park
- Department of Materials Science and Engineering; Hanyang University; Seoul 04763 South Korea
| | - Youngjong Kang
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Myung M. Sung
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
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17
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Park KS, Lee KS, Baek J, Lee L, Son BH, Koo Lee YE, Ahn YH, Park WI, Kang Y, Sung MM. Observation of Charge Separation and Space-Charge Region in Single-Crystal P3HT/C60
Heterojunction Nanowires. Angew Chem Int Ed Engl 2016; 55:10273-7. [DOI: 10.1002/anie.201603961] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Kyung Sun Park
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Ki Seok Lee
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Jangmi Baek
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Lynn Lee
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Byung Hee Son
- Department of Physics; Ajou University; Suwon 16499 South Korea
| | - Yong-Eun Koo Lee
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Yeong Hwan Ahn
- Department of Physics; Ajou University; Suwon 16499 South Korea
| | - Won Il Park
- Department of Materials Science and Engineering; Hanyang University; Seoul 04763 South Korea
| | - Youngjong Kang
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
| | - Myung M. Sung
- Department of Chemistry; Hanyang University; Seoul 04763 South Korea
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Cho SH, Kwon SS, Yi J, Park WI. Chemical and biological sensors based on defect-engineered graphene mesh field-effect transistors. Nano Converg 2016; 3:14. [PMID: 28191424 PMCID: PMC5271147 DOI: 10.1186/s40580-016-0075-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 05/26/2016] [Indexed: 05/26/2023]
Abstract
Graphene has been intensively studied for applications to high-performance sensors, but the sensing characteristics of graphene devices have varied from case to case, and the sensing mechanism has not been satisfactorily determined thus far. In this review, we describe recent progress in engineering of the defects in graphene grown by a silica-assisted chemical vapor deposition technique and elucidate the effect of the defects upon the electrical response of graphene sensors. This review provides guidelines for engineering and/or passivating defects to improve sensor performance and reliability.
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Affiliation(s)
- Seunghee H. Cho
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763 South Korea
| | - Sun Sang Kwon
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763 South Korea
| | - Jaeseok Yi
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763 South Korea
| | - Won Il Park
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763 South Korea
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Kwon SS, Yi J, Lee WW, Shin JH, Kim SH, Cho SH, Nam S, Park WI. Reversible and Irreversible Responses of Defect-Engineered Graphene-Based Electrolyte-Gated pH Sensors. ACS Appl Mater Interfaces 2016; 8:834-839. [PMID: 26692009 DOI: 10.1021/acsami.5b10183] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We have studied the role of defects in electrolyte-gated graphene mesh (GM) field-effect transistors (FETs) by introducing engineered edge defects in graphene (Gr) channels. Compared with Gr-FETs, GM-FETs were characterized as having large increments of Dirac point shift (∼30-100 mV/pH) that even sometimes exceeded the Nernst limit (59 mV/pH) by means of electrostatic gating of H(+) ions. This feature was attributed to the defect-mediated chemisorptions of H(+) ions to the graphene edge, as supported by Raman measurements and observed cycling characteristics of the GM FETs. Although the H(+) ion binding to the defects increased the device response to pH change, this binding was found to be irreversible. However, the irreversible component showed relatively fast decay, almost disappearing after 5 cycles of exposure to solutions of decreasing pH value from 8.25 to 6.55. Similar behavior could be found in the Gr-FET, but the irreversible component of the response was much smaller. Finally, after complete passivation of the defects, both Gr-FETs and GM-FETs exhibited only reversible response to pH change, with similar magnitude in the range of 6-8 mV/pH.
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Affiliation(s)
- Sun Sang Kwon
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
| | - Jaeseok Yi
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
| | - Won Woo Lee
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
| | - Jae Hyeok Shin
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
| | - Su Han Kim
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
| | - Seunghee H Cho
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
| | - SungWoo Nam
- Department of Mechanical Science and Engineering, University of Illinois, Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Won Il Park
- Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea
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Yun SM, Song BG, Choi W, Roh JY, Lee YJ, Park WI, Han MG, Ju YR, Lee WJ. First Isolation of Severe Fever with Thrombocytopenia Syndrome Virus from Haemaphysalis longicornis Ticks Collected in Severe Fever with Thrombocytopenia Syndrome Outbreak Areas in the Republic of Korea. Vector Borne Zoonotic Dis 2016; 16:66-70. [PMID: 26745758 PMCID: PMC4742983 DOI: 10.1089/vbz.2015.1832] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [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] [Indexed: 11/12/2022] Open
Abstract
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease that is endemic to China, Japan, and the Republic of Korea (ROK). In this study, 8313 ticks collected from SFTS outbreak areas in the ROK in 2013 were used to detect the SFTS virus (SFTSV). A single SFTSV was isolated in cell culture from one pool of Haemaphysalis longicornis ticks collected from Samcheok-si, Gangwon Province, in the ROK. Phylogenetic analysis showed that the SFTSV isolate was clustered with the SFTSV strain from Japan, which was isolated from humans. To the best of our knowledge, this is the first isolation in the world of SFTSV in ticks collected from vegetation.
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Affiliation(s)
- Seok-Min Yun
- 1 Division of Arboviruses, National Institute of Health , Korea Centers for Disease Control and Prevention, Cheongju-si, Republic of Korea
| | - Bong Gu Song
- 2 Division of Medical Entomology, National Institute of Health , Korea Centers for Disease Control and Prevention, Cheongju-si, Republic of Korea
| | - WooYoung Choi
- 1 Division of Arboviruses, National Institute of Health , Korea Centers for Disease Control and Prevention, Cheongju-si, Republic of Korea
| | - Jong Yul Roh
- 2 Division of Medical Entomology, National Institute of Health , Korea Centers for Disease Control and Prevention, Cheongju-si, Republic of Korea
| | - Ye-Ji Lee
- 1 Division of Arboviruses, National Institute of Health , Korea Centers for Disease Control and Prevention, Cheongju-si, Republic of Korea
| | - Won Il Park
- 2 Division of Medical Entomology, National Institute of Health , Korea Centers for Disease Control and Prevention, Cheongju-si, Republic of Korea
| | - Myung Guk Han
- 1 Division of Arboviruses, National Institute of Health , Korea Centers for Disease Control and Prevention, Cheongju-si, Republic of Korea
| | - Young Ran Ju
- 2 Division of Medical Entomology, National Institute of Health , Korea Centers for Disease Control and Prevention, Cheongju-si, Republic of Korea
| | - Won-Ja Lee
- 1 Division of Arboviruses, National Institute of Health , Korea Centers for Disease Control and Prevention, Cheongju-si, Republic of Korea
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Lee WW, Chang S, Yang DW, Lee JM, Park HG, Park WI. Three-dimensional epitaxy of single crystalline semiconductors by polarity-selective multistage growth. CrystEngComm 2016. [DOI: 10.1039/c6ce01897a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Xia F, Kwon S, Lee WW, Liu Z, Kim S, Song T, Choi KJ, Paik U, Park WI. Graphene as an Interfacial Layer for Improving Cycling Performance of Si Nanowires in Lithium-Ion Batteries. Nano Lett 2015; 15:6658-6664. [PMID: 26359631 DOI: 10.1021/acs.nanolett.5b02482] [Citation(s) in RCA: 12] [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: 06/05/2023]
Abstract
Managing interfacial instability is crucial for enhancing cyclability in lithium-ion batteries (LIBs), yet little attention has been devoted to this issue until recently. Here, we introduce graphene as an interfacial layer between the current collector and the anode composed of Si nanowires (SiNWs) to improve the cycling capability of LIBs. The atomically thin graphene lessened the stress accumulated by volumetric mismatch and inhibited interfacial reactions that would accelerate the fatigue of Si anodes. By simply incorporating graphene at the interface, we demonstrated significantly enhanced cycling stability for SiNW-based LIB anodes, with retentions of more than 2400 mAh/g specific charge capacity over 200 cycles, 2.7 times that of SiNWs on a bare current collector.
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Affiliation(s)
| | | | | | | | | | - Taeseup Song
- School of Materials Science and Engineering, Yeungnam University , Gyeongsan 712-749, Korea
| | - Kyoung Jin Choi
- School of Materials Science and Engineering, Ulsan National Institute of Science & Technology (UNIST) , Ulsan 689-798, Korea
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23
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Lee YS, Choi JW, Bae EJ, Park WI, Lee HJ, Oh PS. The corrected QT (QTc) prolongation in hyperthyroidism and the association of thyroid hormone with the QTc interval. Korean J Pediatr 2015; 58:263-6. [PMID: 26300941 PMCID: PMC4543186 DOI: 10.3345/kjp.2015.58.7.263] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 09/04/2014] [Accepted: 10/20/2014] [Indexed: 11/30/2022]
Abstract
Purpose Ventricular repolarization is assessed using the QT interval corrected by the heart rate (QTc) via an electrocardiogram (ECG). Prolonged QTc is associated with an increased risk of arrhythmias and cardiac mortality. As there have been few reports regarding the effects of hyperthyroidism on ventricular repolarization, we studied the association between serum free thyroxine (free T4 [fT4]) and thyroid stimulating hormone (TSH) levels and the QTc interval. Methods Thirty-eight patients with hyperthyroidism (<30 years old) were included, and we used their clinical records and available ECGs (between August 2003 and August 2011) to evaluate the association between their fT4 and TSH levels and their QTc interval. In addition, we studied the ECGs of 72 age-matched patients with no hyperthyroidism (control group) and compared their data with that from the patients group. Results The QTc duration in patients with hyperthyroidism was significantly prolonged compared to that in the control subjects (P<0.001). In addition, the number of hyperthyroid patients with abnormal prolonged QTc was significantly higher than that in the control group (P<0.001). Among the patients with hyperthyroidism, patients with prolonged QTc and borderline QTc had higher fT4 levels and there was positive correlation between their fT4 levels and their QTc interval (P<0.05). However, no correlation was observed between their TSH levels and their QTc interval. Conclusion We report that hyperthyroidism is associated with QTc prolongation. The correlation between the fT4 levels and the QTc interval suggests that thyroid status is associated with QTc values and the risk of cardiac mortality.
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Affiliation(s)
- Ye Seung Lee
- Department of Pediatrics, Hallym University College of Medicine, Chuncheon, Korea
| | - Joong Wan Choi
- Department of Pediatrics, Hallym University College of Medicine, Chuncheon, Korea
| | - Eun Ju Bae
- Department of Pediatrics, Hallym University College of Medicine, Chuncheon, Korea
| | - Won Il Park
- Department of Pediatrics, Hallym University College of Medicine, Chuncheon, Korea
| | - Hong Jin Lee
- Department of Pediatrics, Hallym University College of Medicine, Chuncheon, Korea
| | - Phil Soo Oh
- Department of Pediatrics, Hallym University College of Medicine, Chuncheon, Korea
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Kim YJ, Yun TG, Choi IC, Kim S, Park WI, Han SM, Jang JI. Time-dependent mechanical-electrical coupled behavior in single crystal ZnO nanorods. Sci Rep 2015; 5:9716. [PMID: 25982962 PMCID: PMC4434914 DOI: 10.1038/srep09716] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [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: 08/26/2014] [Accepted: 03/17/2015] [Indexed: 11/09/2022] Open
Abstract
Nanoscale time-dependent mechanical-electrical coupled behavior of single crystal ZnO nanorods was systematically explored, which is essential for accessing the long-term reliability of the ZnO nanorod-based flexible devices. A series of compression creep tests combined with in-situ electrical measurement was performed on vertically-grown single crystal ZnO nanorods. Continuous measurement of the current (I)-voltage (V) curves before, during, after the creep tests revealed that I is non-negligibly increased as a result of the time-dependent deformation. Analysis of the I-V curves based on the thermionic emission-diffusion theory allowed extraction of nanorod resistance, which was shown to decrease as time-dependent deformation. Finally, based on the observations in this study, a simple analytical model for predicting the reduction in nanorod resistance as a function of creep strain that is induced from diffusional mechanisms is proposed, and this model was demonstrated to be in an excellent agreement with the experimental results.
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Affiliation(s)
- Yong-Jae Kim
- Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea
- Graduate School of EEWS, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Tae Gwang Yun
- Graduate School of EEWS, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - In-Chul Choi
- Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea
| | - Sungwoong Kim
- Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea
| | - Won Il Park
- Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea
| | - Seung Min Han
- Graduate School of EEWS, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Jae-il Jang
- Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea
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Jang YJ, Kim JY, Lee KB, Na GW, Lee WJ, Park WI, Lee M. Spontaneous perforation and dissection of the sinus of Valsalva and interventricular septum with intracardiac thrombus in a patient with Behcet's disease. Korean J Intern Med 2015; 30:252-5. [PMID: 25750569 PMCID: PMC4351334 DOI: 10.3904/kjim.2015.30.2.252] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/22/2014] [Accepted: 08/20/2014] [Indexed: 02/07/2023] Open
Affiliation(s)
- Yoon-Jung Jang
- Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
| | - Jun Young Kim
- Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
| | - Kyung Been Lee
- Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
| | - Gun Wung Na
- Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
| | - Won Jae Lee
- Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
| | - Won Il Park
- Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
| | - Mirae Lee
- Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
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Bang J, Choi J, Xia F, Kwon SS, Ashraf A, Park WI, Nam S. Assembly and densification of nanowire arrays via shrinkage. Nano Lett 2014; 14:3304-3308. [PMID: 24837133 DOI: 10.1021/nl500709p] [Citation(s) in RCA: 8] [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: 06/03/2023]
Abstract
Chemically synthesized semiconductor nanowires (NWs) have demonstrated substantial promise for nanoelectronics, nanoenergy, and nanobiotechnology, but the lack of an effective and controllable assembly process has limited the wide adoption of NWs in these areas. Here we demonstrate a facile, robust, and controllable approach to assembling and densifying a parallel array of NWs using shrinkable shape memory polymers. Using thermal-induced shrinkage of polystyrene, we were able to successfully assemble and densify NW arrays up to close-packing and, furthermore, achieve tunable density (up to ∼300% amplification of density) by controlling the shrinkage process. We also demonstrate scalable assembly and densification of NWs on a 2.5 × 6 inch scale to explore the manufacturability of the shrink-induced assembly process. Finally, we demonstrate the successful transfer of the shrink-assembled NW arrays onto various 2-dimensional and 3-dimensional substrates without compromising the integrity of NW assembly and density.
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Affiliation(s)
- Jaehoon Bang
- Department of Mechanical Science and Engineering, University of Illinois, Urbana-Champaign , Urbana, Illinois 61801, United States
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27
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Lee YS, Kim HK, Kim HR, Lee JY, Choi JW, Bae EJ, Oh PS, Park WI, Ki CS, Lee HJ. Identification of a novel mutation in a patient with pseudohypoparathyroidism type Ia. Korean J Pediatr 2014; 57:240-4. [PMID: 25045367 PMCID: PMC4102687 DOI: 10.3345/kjp.2014.57.5.240] [Citation(s) in RCA: 3] [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] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/11/2013] [Accepted: 07/18/2013] [Indexed: 12/24/2022]
Abstract
Pseudohypoparathyroidism type Ia (PHP Ia) is a disorder characterized by multiform hormonal resistance including parathyroid hormone (PTH) resistance and Albright hereditary osteodystrophy (AHO). It is caused by heterozygous inactivating mutations within the Gs alpha-encoding GNAS exons. A 9-year-old boy presented with clinical and laboratory abnormalities including hypocalcemia, hyperphosphatemia, PTH resistance, multihormone resistance and AHO (round face, short stature, obesity, brachydactyly and osteoma cutis) which were typical of PHP Ia. He had a history of repeated convulsive episodes that started from the age of 2 months. A cranial computed tomography scan showed bilateral calcifications in the basal ganglia and his intelligence quotient testing indicated mild mental retardation. Family history revealed that the patient's maternal relatives, including his grandmother and 2 of his mother's siblings, had features suggestive of AHO. Sequencing of the GNAS gene of the patient identified a heterozygous nonsense mutation within exon 11 (c.637 C>T). The C>T transversion results in an amino acid substitution from Gln to stop codon at codon 213 (p.Gln213*). To our knowledge, this is a novel mutation in GNAS.
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Affiliation(s)
- Ye Seung Lee
- Department of Pediatrics, Hallym University College of Medicine, Chunchon, Korea
| | - Hui Kwon Kim
- Department of Pediatrics, Hallym University College of Medicine, Chunchon, Korea
| | - Hye Rim Kim
- Department of Pediatrics, Hallym University College of Medicine, Chunchon, Korea
| | - Jong Yoon Lee
- Department of Pediatrics, Hallym University College of Medicine, Chunchon, Korea
| | - Joong Wan Choi
- Department of Pediatrics, Hallym University College of Medicine, Chunchon, Korea
| | - Eun Ju Bae
- Department of Pediatrics, Hallym University College of Medicine, Chunchon, Korea
| | - Phil Soo Oh
- Department of Pediatrics, Hallym University College of Medicine, Chunchon, Korea
| | - Won Il Park
- Department of Pediatrics, Hallym University College of Medicine, Chunchon, Korea
| | - Chang Seok Ki
- Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hong Jin Lee
- Department of Pediatrics, Hallym University College of Medicine, Chunchon, Korea
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Shin EH, Roh JY, Park WI, Song BG, Chang KS, Lee WG, Lee HI, Park C, Park MY, Shin EH. Transovarial transmission of Orientia tsutsugamushi in Leptotrombidium palpale (Acari: Trombiculidae). PLoS One 2014; 9:e88453. [PMID: 24721932 PMCID: PMC3982952 DOI: 10.1371/journal.pone.0088453] [Citation(s) in RCA: 9] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/13/2014] [Indexed: 11/19/2022] Open
Abstract
Transovarial transmission of Orientia tsutsugamushi in colonies of Leptotrombidium palpale was studied in the parent and F1 and F2 generations. Both transovarial transmission and filial infection rates were 100% in the parent and F1 generations of Leptotrombidium palpale. The filial infection rate in the F1 generation was 100%, but it declined to 94.3% in the F2 progeny. The sex ratio of the F1 generation from infected L. palpale was 1∶0.8 (male:female) and the proportion of males was relatively high. This study is the first to report on the transovarial transmission of O. tsutsugamushi in L. palpale. High transovarial transmission rates in L. palpale suggest that this species might be one of the major vectors of tsutsugamushi disease in Korea.
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Affiliation(s)
- Eun Hee Shin
- Division of Medical Entomology, Center for Immunology and Pathology, Korea National Institute of Health, Cheongwon, South Korea
| | - Jong Yul Roh
- Division of Medical Entomology, Center for Immunology and Pathology, Korea National Institute of Health, Cheongwon, South Korea
| | - Won Il Park
- Division of Medical Entomology, Center for Immunology and Pathology, Korea National Institute of Health, Cheongwon, South Korea
| | - Bong Gu Song
- Division of Medical Entomology, Center for Immunology and Pathology, Korea National Institute of Health, Cheongwon, South Korea
| | - Kyu-Sik Chang
- Division of Medical Entomology, Center for Immunology and Pathology, Korea National Institute of Health, Cheongwon, South Korea
| | - Wook-Gyo Lee
- Division of Medical Entomology, Center for Immunology and Pathology, Korea National Institute of Health, Cheongwon, South Korea
| | - Hee Il Lee
- Division of Biosafety Evaluation and Control, Korea National Institute of Health, Cheongwon, South Korea
| | - Chan Park
- Division of Arboviruses, Center for Immunology and Pathology, Korea National Institute of Health, Cheongwon, South Korea
| | - Mi-Yeoun Park
- Division of Medical Entomology, Center for Immunology and Pathology, Korea National Institute of Health, Cheongwon, South Korea
| | - E-Hyun Shin
- Division of Medical Entomology, Center for Immunology and Pathology, Korea National Institute of Health, Cheongwon, South Korea
- * E-mail:
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Yun SM, Song BG, Choi W, Park WI, Kim SY, Roh JY, Ryou J, Ju YR, Park C, Shin EH. Prevalence of tick-borne encephalitis virus in ixodid ticks collected from the republic of Korea during 2011-2012. Osong Public Health Res Perspect 2013; 3:213-21. [PMID: 24159517 PMCID: PMC3747658 DOI: 10.1016/j.phrp.2012.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [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: 08/26/2012] [Revised: 10/12/2012] [Accepted: 10/15/2012] [Indexed: 12/30/2022] Open
Abstract
Objectives In this study, we demonstrated that TBEV-infected ticks have been distributed in the ROK, combined with our previous results. These results suggest that TBEV may exist in the ROK, and H. longicornis, H. flava, and I. nipponensis may be potential vectors of TBEV. In addition, these results emphasize the need for further epidemiological research of TBEV. Methods We examined for the presence of RNA of TBEV by reverse transcriptase-nested polymerase chain reaction (RT-nested PCR) using ixodid ticks captured in 25 localities of 10 provinces. Ticks were collected by the flagging and dragging method or using sentinel BG traps at forests, grass thickets, and grassland. A total of 13,053 ticks belonging to two genera and four species were collected and pooled (1292 pools), according to collection site, species of tick, and developmental stage. Results Among 1292 pools, the envelope (E) protein gene of TBEV was detected using RT-nested PCR in 10 pools (3 pools of the 1,331 adult ticks and 7 pools of the 11,169 nymph ticks) collected from Gangwon-do province, Jeonrabuk-do province, and Jeju Island. The minimum infection rates for TBEV of Haemaphysalis longicornis, Haemaphysalis flava, and Ixodes nipponensis were 0.06%, 0.17%, and 2.38%, respectively. Phylogenetic analysis based on the partial E protein gene was performed to identify relationships between the TBEV strains. This showed that 10 Korean strains clustered with the Western subtype. Conclusion In this study, we investigated the prevalence of tick-borne encephalitis virus (TBEV) in ixodid ticks from various regions of the Republic of Korea (ROK) during 2011–2012 to identify whether TBEV is circulating and to determine the endemic regions of TBEV.
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Affiliation(s)
- Seok-Min Yun
- Division of Arboviruses, Korea National Institute of Health, Osong, Korea
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Xia F, Kim SB, Cheng H, Lee JM, Song T, Huang Y, Rogers JA, Paik U, Park WI. Facile synthesis of free-standing silicon membranes with three-dimensional nanoarchitecture for anodes of lithium ion batteries. Nano Lett 2013; 13:3340-3346. [PMID: 23750947 DOI: 10.1021/nl401629q] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We propose a facile method for synthesizing a novel Si membrane structure with good mechanical strength and three-dimensional (3D) configuration that is capable of accommodating the large volume changes associated with lithiation in lithium ion battery applications. The membrane electrodes demonstrated a reversible charge capacity as high as 2414 mAh/g after 100 cycles at current density of 0.1 C, maintaining 82.3% of the initial charge capacity. Moreover, the membrane electrodes showed superiority in function at high current density, indicating a charge capacity >1220 mAh/g even at 8 C. The high performance of the Si membrane anode is assigned to their characteristic 3D features, which is further supported by mechanical simulation that revealed the evolution of strain distribution in the membrane during lithiation reaction. This study could provide a model system for rational and precise design of the structure and dimensions of Si membrane structures for use in high-performance lithium ion batteries.
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Affiliation(s)
- Fan Xia
- Department of Materials Science and Engineering, Hanyang University , Seoul 133-791, Korea
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Kwon HS, Cho YK, Sohn IS, Hwang HS, Seo KJ, Park WI, Seo YS. Rupture of a pseudoaneurysm as a rare cause of severe postpartum hemorrhage: analysis of 11 cases and a review of the literature. Eur J Obstet Gynecol Reprod Biol 2013; 170:56-61. [PMID: 23746797 DOI: 10.1016/j.ejogrb.2013.04.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [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: 12/26/2012] [Revised: 03/29/2013] [Accepted: 04/22/2013] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To clarify the clinical features of severe postpartum hemorrhage (PPH) resulting from a ruptured pseudoaneurysm and to determine the efficacy of selective arterial embolization as a method of management. STUDY DESIGN Eleven women who underwent selective arterial embolization for treatment of severe hemorrhage due to a ruptured pseudoaneurysm were identified from 2 hospitals within the past 5 years. A retrospective analysis was performed to identify the clinical characteristics of the hemorrhage and to evaluate the efficacy of arterial embolization. RESULTS Nine women delivered by cesarean delivery. Eight of the 11 women had late PPH with onset of bleeding occurring 6-100 days (median, 11.5) after delivery. The average volume of transfusion was 3196 ml of packed red blood cells (range, 1600-8980 ml). Uterine atony occurred in only one patient and was accompanied by an intrauterine abscess. Administration of uterotonic agents did not diminish the bleeding. Only one patient out of 11 underwent re-embolization. CONCLUSION If late PPH without uterine infection or retained placenta occurs after cesarean delivery, one should suspect the possibility of a ruptured pseudoaneurysm. Selective arterial embolization may be considered as a primary means of treatment.
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Affiliation(s)
- Han-Sung Kwon
- Department of Obstetrics and Gynecology, Konkuk University School of Medicine, Seoul, Republic of Korea
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Kim YH, Kwon SH, Lee JM, Hwang MS, Kang JH, Park WI, Park HG. Graphene-contact electrically driven microdisk lasers. Nat Commun 2013; 3:1123. [PMID: 23047681 PMCID: PMC3493654 DOI: 10.1038/ncomms2137] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [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: 08/20/2012] [Accepted: 09/17/2012] [Indexed: 11/10/2022] Open
Abstract
Active nanophotonic devices are attractive due to their low-power consumption, ultrafast modulation speed and high-density integration. Although electrical operation is required for practical implementation of these devices, it is not straightforward to introduce a proper current path into such a wavelength-scale nanostructure without affecting the optical properties. For example, to demonstrate electrically driven nanolasers, complicated fabrication techniques have been used thus far. Here we report an electrically driven microdisk laser using a transparent graphene electrode. Current is injected efficiently through the graphene sheet covering the top surface of the microdisk cavity, and, for the first time, lasing operation was achieved with a low-threshold current of ~300 μA at room temperature. In addition, we measured significant electroluminescence from a graphene-contact subwavelength-scale single nanopillar structure. This work represents a new paradigm for the practical applications of integrated photonic systems, by conformally mounting graphene on the complex surfaces of non-planar three-dimensional nanostructures.
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Affiliation(s)
- Yoon-Ho Kim
- Department of Physics, Korea University, Seoul 136-701, Republic of Korea
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Lee DH, Yi J, Lee JM, Lee SJ, Doh YJ, Jeong HY, Lee Z, Paik U, Rogers JA, Park WI. Engineering electronic properties of graphene by coupling with Si-rich, two-dimensional islands. ACS Nano 2013; 7:301-307. [PMID: 23234234 DOI: 10.1021/nn304007x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Recent theoretical and experimental studies demonstrated that breaking of the sublattice symmetry in graphene produces an energy gap at the former Dirac point. We describe the synthesis of graphene sheets decorated with ultrathin, Si-rich two-dimensional (2D) islands (i.e., Gr:Si sheets), in which the electronic property of graphene is modulated by coupling with the Si-islands. Analyses based on transmission electron microscopy, atomic force microscopy, and electron and optical spectroscopies confirmed that Si-islands with thicknesses of ~2 to 4 nm and a lateral size of several tens of nm were bonded to graphene via van der Waals interactions. Field-effect transistors (FETs) based on Gr:Si sheets exhibited enhanced transconductance and maximum-to-minimum current level compared to bare-graphene FETs, and their magnitudes gradually increased with increasing coverage of Si layers on the graphene. The temperature dependent current-voltage measurements of the Gr:Si sheet showed approximately a 2-fold increase in the resistance by decreasing the temperature from 250 to 10 K, which confirmed the opening of the substantial bandgap (~2.5-3.2 meV) in graphene by coupling with Si islands.
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Affiliation(s)
- Dong Hyun Lee
- Department of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea
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Kim SB, Lee WW, Yi J, Park WI, Kim JS, Nichols WT. Simple, large-scale patterning of hydrophobic ZnO nanorod arrays. ACS Appl Mater Interfaces 2012; 4:3910-3915. [PMID: 22734585 DOI: 10.1021/am3007142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Here we describe a simple, versatile technique to produce large-scale arrays of highly ordered ZnO nanorods. Patterning of three distinct ZnO crystal morphologies is demonstrated through use of different ZnO seed layers. Array formation is accomplished through a simple variation on nanosphere lithography that imprints a thickness variation across a PMMA mask layer. The area of exposed seed layer is controlled through etching time in an oxygen plasma. Subsequent hydrothermal growth from the patterned seed layer produces high-quality ZnO crystals in uniform arrays. The high uniformity of the patterned array is shown to induce a high contact angle hydrophobic state even without the need for chemical modification of the ZnO surface. This technique provides a straightforward way to integrate the optical and electrical properties of high-quality ZnO nanorods with the tunable fluidic properties at the surface of well-ordered arrays.
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Affiliation(s)
- Seong Been Kim
- Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea
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Abstract
Biosilification is of interest due to its capability to produce a highly intricate structure under environmentally friendly conditions. Despite the considerable effort that has been devoted toward biomimetic silification, the synthesis of highly complex silica structures, as found in the structures of diatom cell walls, is still in its infancy. Here, we report the bioinspired fabrication of well-organized and symmetric silica nanostructured networks, involving phase separation and silicic acid polymerization processes, in analogy to the morphogenesis of diatom cell walls. Our approach exploits self-assembled silica spheres as a self-source of the silicic acids as well as scaffolds that, interplayed with droplets of ammonium hexafluorosilicate, direct the site-specific silification. Moreover, we have achieved multiple morphological evolutions with subtle changes in the process, which demonstrates exquisite levels of control over silica morphogenesis.
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Affiliation(s)
- Jaeseok Yi
- Division of Materials Science Engineering, Hanyang University, Seoul 133-791, Korea
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Song T, Cheng H, Choi H, Lee JH, Han H, Lee DH, Yoo DS, Kwon MS, Choi JM, Doo SG, Chang H, Xiao J, Huang Y, Park WI, Chung YC, Kim H, Rogers JA, Paik U. Si/Ge double-layered nanotube array as a lithium ion battery anode. ACS Nano 2012; 6:303-309. [PMID: 22142021 DOI: 10.1021/nn203572n] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Problems related to tremendous volume changes associated with cycling and the low electron conductivity and ion diffusivity of Si represent major obstacles to its use in high-capacity anodes for lithium ion batteries. We have developed a group IVA based nanotube heterostructure array, consisting of a high-capacity Si inner layer and a highly conductive Ge outer layer, to yield both favorable mechanics and kinetics in battery applications. This type of Si/Ge double-layered nanotube array electrode exhibits improved electrochemical performances over the analogous homogeneous Si system, including stable capacity retention (85% after 50 cycles) and doubled capacity at a 3C rate. These results stem from reduced maximum hoop strain in the nanotubes, supported by theoretical mechanics modeling, and lowered activation energy barrier for Li diffusion. This electrode technology creates opportunities in the development of group IVA nanotube heterostructures for next generation lithium ion batteries.
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Affiliation(s)
- Taeseup Song
- Department of Materials Science Engineering, Hanyang University, Seoul 133-791, Korea
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Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is a rare condition originally described by Hutchinson in 1886. Death result from cardiac complications in the majority of cases and usually occurs at average age of thirteen years. A 4-yr old boy had typical clinical findings such as short stature, craniofacial disproportion, alopecia, prominent scalp veins and sclerodermatous skin. This abnormal appearance began at age of 1 yr. On serological and hormonal evaluation, all values are within normal range. He was neurologically intact with motor and mental development. An echocardiogram showed calcification of aortic and mitral valves. Hypertrophy of internal layer at internal carotid artery suggesting atherosclerosis was found by carotid doppler sonography. He is on low dose aspirin to prevent thromboembolic episodes and on regular follow up. Gene study showed typical G608G (GGC- > GGT) point mutation at exon 11 in LMNA gene. This is a rare case of Hutchinson-Gilford progeria syndrome confirmed by genetic analysis in Korea.
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Affiliation(s)
- Hui Kwon Kim
- Department of Pediatrics, College of Medicine, Hallym University, Chunchon, Korea
| | - Jong Yoon Lee
- Department of Pediatrics, College of Medicine, Hallym University, Chunchon, Korea
| | - Eun Ju Bae
- Department of Pediatrics, College of Medicine, Hallym University, Chunchon, Korea
| | - Phil Soo Oh
- Department of Pediatrics, College of Medicine, Hallym University, Chunchon, Korea
| | - Won Il Park
- Department of Pediatrics, College of Medicine, Hallym University, Chunchon, Korea
| | - Dong Sung Lee
- Department of Biochemistry and Molecular Biology, College of Medicine, Seoul National University, Seoul Korea
| | - Jong-Il Kim
- Department of Biochemistry and Molecular Biology, College of Medicine, Seoul National University, Seoul Korea
| | - Hong Jin Lee
- Department of Pediatrics, College of Medicine, Hallym University, Chunchon, Korea
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Samal M, Lee JM, Park WI, Yi DK, Paik U, Lee CL. Surface morphology changes of graphene on flexible PET substrate upon thermal annealing. J Nanosci Nanotechnol 2011; 11:10069-10077. [PMID: 22413346 DOI: 10.1166/jnn.2011.4977] [Citation(s) in RCA: 3] [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: 05/31/2023]
Abstract
The performance of a polymer photovoltaic device using multilayered graphene on an amorphous PET substrate as the electrode was studied. The changes in surface morphology of graphene coated polyethylene terephthalate (PETG) substrate upon thermal annealing were investigated by atomic force microscopy (AFM), field emission scanning electron microscope (FE-SEM) and current-voltage characteristics. The root mean square (RMS) roughness of PETG substrate before annealing was 36.5 nm that decreased to 11.5 nm after 10 min thermal annealing at 110 degrees C. The mean grain size of the substrate decreased from 2301 nm2 to 848 nm2. The PETG surface became smooth when thermally annealed as the voids created by the bubbles in the graphene layer were filled up with thermal expansion of the PET substrate. However, cracks present initially on the graphene due to surface stress between the graphene and PET layer grew further upon annealing that deteriorated the device performance. This study on the graphene surface morphology change upon annealing and the consequent drop in device performance vis-à-vis an ITO glass electrode shows potential drawback of solar cell device fabrication on such flexible substrates.
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Affiliation(s)
- Monica Samal
- Division of Bionanotechnology, Gachon Bionano Institute, Kyungwon University, Seongnam, 461-701, Korea
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Abstract
This article presents a review of current research activities on the hybrid heterostructures of inorganic nanostructures grown directly on graphene layers, which can be categorized primarily as zero-dimensional nanoparticles; one-dimensional nanorods, nanowires, and nanotubes; and two-dimensional nanowalls. For the hybrid structures, the nanostructures exhibit excellent material characteristics including high carrier mobility and radiative recombination rate as well as long-term stability while graphene films show good optical transparency, mechanical flexibility, and electrical conductivity. Accordingly, the versatile and fascinating properties of the nanostructures grown on graphene layers make it possible to fabricate high-performance optoelectronic and electronic devices even in transferable, flexible, or stretchable forms. Here, we review preparation methods and possible device applications of the hybrid structures consisting of various types of inorganic nanostructures grown on graphene layers.
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Affiliation(s)
- Won Il Park
- Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea.
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Son DI, Shim JH, Park DH, Jung JH, Lee JM, Park WI, Kim TW, Choi WK. Polymer-ultrathin graphite sheet-polymer composite structured flexible nonvolatile bistable organic memory devices. Nanotechnology 2011; 22:295203. [PMID: 21685558 DOI: 10.1088/0957-4484/22/29/295203] [Citation(s) in RCA: 4] [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: 05/30/2023]
Abstract
We present data, which were obtained before bending and after bending, for the electrical bistabilities, memory stabilities, and memory mechanisms of three-layer structured flexible bistable organic memory (BOM) devices, which were fabricated utilizing the ultrathin graphite sheets (UGS) sandwiched between insulating poly(methylmethacrylate) (PMMA) polymer layers. The UGS were formed by transferring UGS (about 30 layers) and using a simple spin-coating technique. Transmission electron microscopy (TEM) measurements were performed to investigate the microstructural properties of the PMMA/UGS/PMMA films. Current-voltage (I-V) measurements were carried out to investigate the electrical properties of the BOM devices containing the UGS embedded in the PMMA polymer. Current-time (I-t) and current-cycle measurements under flat and bent conditions were performed to investigate the memory stabilities of the BOM devices. The memory characteristics of the BOM maintained similar device efficiencies after bending and were stable during repeated bendings of the BOM devices. The mechanisms for these characteristics of the fabricated BOM are described on the basis of the I-V results.
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Affiliation(s)
- Dong Ick Son
- Future Convergence Research Division, Korea Institute of Science and Technology, Cheongryang, Seoul, Korea
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41
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Song T, Lee DH, Kwon MS, Choi JM, Han H, Doo SG, Chang H, Park WI, Sigmund W, Kim H, Paik U. Silicon nanowires with a carbon nanofiber branch as lithium-ion anode material. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm12511g] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Park EJ, Shin JJW, Seo YS, Kim DW, Hong SY, Park WI, Kang BM. Gonadotropin-releasing hormone-agonist induces apoptosis of human granulosa-luteal cells via caspase-8, -9 and -3, and poly-(ADP-ribose)-polymerase cleavage. Biosci Trends 2011; 5:120-8. [DOI: 10.5582/bst.2011.v5.3.120] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Eun Joo Park
- Department of Obstetrics and Gynecology, Eulji Medical Center of Eulji University
| | - JJung Whan Shin
- Department of Obstetrics and Gynecology, Eulji Medical Center of Eulji University
| | - Yong Soo Seo
- Department of Obstetrics and Gynecology, Eulji Medical Center of Eulji University
| | - Dae Wun Kim
- Department of Obstetrics and Gynecology, Eulji Medical Center of Eulji University
| | - Seo Yoo Hong
- Department of Obstetrics and Gynecology, Eulji Medical Center of Eulji University
| | - Won Il Park
- Department of Obstetrics and Gynecology, Eulji Medical Center of Eulji University
| | - Byung Moon Kang
- Department of Obstetrics and Gynecology, Asan Medical Center of Ulsan University
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Lee JM, Choung JW, Yi J, Lee DH, Samal M, Yi DK, Lee CH, Yi GC, Paik U, Rogers JA, Park WI. Vertical pillar-superlattice array and graphene hybrid light emitting diodes. Nano Lett 2010; 10:2783-2788. [PMID: 20608711 DOI: 10.1021/nl100648y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We report a type of device that combines vertical arrays of one-dimensional (1D) pillar-superlattice (PSL) structures with 2D graphene sheets to yield a class of light emitting diode (LED) with interesting mechanical, optical, and electrical characteristics. In this application, graphene sheets coated with very thin metal layers exhibit good mechanical and electrical properties and an ability to mount, in a freely suspended configuration, on the PSL arrays as a top window electrode. Optical characterization demonstrates that graphene exhibits excellent optical transparency even after deposition of the thin metal films. Thermal annealing of the graphene/metal (Gr/M) contact to the GaAs decreases the contact resistance, to provide enhanced carrier injection. The resulting PSL-Gr/M LEDs exhibit bright light emission over large areas. The result suggests the utility of graphene-based materials as electrodes in devices with unusual, nonplanar 3D architectures.
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Affiliation(s)
- Jung Min Lee
- Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea
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Son DI, Kim TW, Shim JH, Jung JH, Lee DU, Lee JM, Park WI, Choi WK. Flexible organic bistable devices based on graphene embedded in an insulating poly(methyl methacrylate) polymer layer. Nano Lett 2010; 10:2441-2447. [PMID: 20504010 DOI: 10.1021/nl1006036] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The electrical properties of flexible nonvolatile organic bistable devices (OBDs) fabricated with graphene sandwiched between two insulating poly(methyl methacrylate) (PMMA) polymer layers were investigated. Current-voltage (I-V) measurements on the Al/PMMA/graphene/PMMA/indium-tin-oxide/poly(ethylene terephthalate) devices at 300 K showed a current bistability due to the existence of the graphene, indicative of charge storage in the graphene. The maximum ON/OFF ratio of the current bistability for the fabricated OBDs was as large as 1 x 10(7), and the endurance number of ON/OFF switchings was 1.5 x 10(5) cycles, and an ON/OFF ratio of 4.4 x 10(6) was maintained for retention times larger than 1 x 10(5) s. No interference effect was observed for the scaled-down OBDs containing a graphene layer. The memory characteristics of the OBDs maintained similar device efficiencies after bending and were stable during repetitive bendings of the OBDs. The mechanisms for these characteristics of the fabricated OBDs are described on the basis of the I-V results.
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Affiliation(s)
- Dong Ick Son
- Department of Information Display Engineering, Hanyang University, Seoul, Korea
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45
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Song T, Xia J, Lee JH, Lee DH, Kwon MS, Choi JM, Wu J, Doo SK, Chang H, Park WI, Zang DS, Kim H, Huang Y, Hwang KC, Rogers JA, Paik U. Arrays of sealed silicon nanotubes as anodes for lithium ion batteries. Nano Lett 2010; 10:1710-6. [PMID: 20369889 DOI: 10.1021/nl100086e] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Silicon is a promising candidate for electrodes in lithium ion batteries due to its large theoretical energy density. Poor capacity retention, caused by pulverization of Si during cycling, frustrates its practical application. We have developed a nanostructured form of silicon, consisting of arrays of sealed, tubular geometries that is capable of accommodating large volume changes associated with lithiation in battery applications. Such electrodes exhibit high initial Coulombic efficiencies (i.e., >85%) and stable capacity-retention (>80% after 50 cycles), due to an unusual, underlying mechanics that is dominated by free surfaces. This physics is manifested by a strongly anisotropic expansion in which 400% volumetric increases are accomplished with only relatively small (<35%) changes in the axial dimension. These experimental results and associated theoretical mechanics models demonstrate the extent to which nanoscale engineering of electrode geometry can be used to advantage in the design of rechargeable batteries with highly reversible capacity and long-term cycle stability.
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Affiliation(s)
- Taeseup Song
- Division of Materials Science Engineering, Hanyang University, Seoul, Korea
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Pyun YB, Yi J, Lee DH, Son KS, Liu G, Yi DK, Paik U, Park WI. Synthesis of ZnO nanotubes and nanotube-nanorod hybrid hexagonal networks using a hexagonally close-packed colloidal monolayer template. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm00011f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ryu SY, Xiao J, Park WI, Son KS, Huang YY, Paik U, Rogers JA. Lateral buckling mechanics in silicon nanowires on elastomeric substrates. Nano Lett 2009; 9:3214-9. [PMID: 19670847 DOI: 10.1021/nl901450q] [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] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We describe experimental and theoretical studies of the buckling mechanics in silicon nanowires (SiNWs) on elastomeric substrates. The system involves randomly oriented SiNWs grown using established procedures on silicon wafers, and then transferred and organized into aligned arrays on prestrained slabs of poly(dimethylsiloxane) (PDMS). Releasing the prestrain leads to nonlinear mechanical buckling processes that transform the initially linear SiNWs into sinusoidal (i.e., "wavy") shapes. The displacements associated with these waves lie in the plane of the substrate, unlike previously observed behavior in analogous systems of silicon nanoribbons and carbon nanotubes where motion occurs out-of-plane. Theoretical analysis indicates that the energy associated with this in-plane buckling is slightly lower than the out-of-plane case for the geometries and mechanical properties that characterize the SiNWs. An accurate measurement of the Young's modulus of individual SiNWs, between approximately 170 and approximately 110 GPa for the range of wires examined here, emerges from comparison of theoretical analysis to experimental observations. A simple strain gauge built using SiNWs in these wavy geometries demonstrates one area of potential application.
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Affiliation(s)
- Seung Yoon Ryu
- Division of Materials Science Engineering, Hanyang University, Seongdong-gu, Seoul 133-791, Republic of Korea
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Kwak JJ, Park WI, Shin H, Choi HM, Nho H. Effects Of 16-wk Jajun Dance Program And Circuit Exercise Training In Improving Physical Fitness, Risk Factors Of Cardiovascular Diseases In Menopausal Women. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000355385.42425.71] [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: 11/21/2022]
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Park WI, Lee CH, Chae JH, Lee DH, Yi GC. Ultrafine ZnO nanowire electronic device arrays fabricated by selective metal-organic chemical vapor deposition. Small 2009; 5:181-4. [PMID: 19107888 DOI: 10.1002/smll.200800617] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- Won Il Park
- Division of Materials Science and Engineering, Hanyang University, Seoul, Korea.
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Cheong HJ, Kim HR, Lee SS, Bae EJ, Park WI, Lee HJ, Choi HC. Inherited metabolic diseases in the urine organic acid analysis of complex febrile seizure patients. Korean J Pediatr 2009. [DOI: 10.3345/kjp.2009.52.2.199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Hee Jeong Cheong
- Department of Pediatrics, College of Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea
| | - Hye Rim Kim
- Department of Pediatrics, College of Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea
| | - Seong Soo Lee
- Department of Pediatrics, College of Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea
| | - Eun Joo Bae
- Department of Pediatrics, College of Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea
| | - Won Il Park
- Department of Pediatrics, College of Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea
| | - Hong Jin Lee
- Department of Pediatrics, College of Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea
| | - Hui Chul Choi
- Department of Neurology, College of Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea
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