Choi S.-H.,Korea Electronics Technology Institute |
Choi S.-H.,Korea University |
Kim J.-S.,Dong - A University |
Woo S.-G.,Korea Electronics Technology Institute |
And 6 more authors.
ACS Applied Materials and Interfaces | Year: 2015
The reversible capacity of Chevrel Mo6S8 cathode can be increased by the simple addition of the Cu metal to Mo6S8 electrodes. However, the exact reaction mechanism of the additional reversible capacity for the Mo6S8 and Cu mixture cathode has not been clearly understood yet. To clarify this unusual behavior, we synthesize a novel Cu nanoparticle/graphene composite for the preparation of the mixture electrode. We thoroughly investigate the electrochemical behaviors of the Mo6S8 and Cu mixture cathode with the relevant structural verifications during Mg2+ insertion and extraction. The in situ formation of CuxMo6S8 is observed, indicating the spontaneous electrochemical insertion of Cu to the Mo6S8 host from the Cu nanoparticle/graphene composite. The reversible electrochemical replacement reaction of Cu in the Mo6S8 structure is clarified with the direct evidence for the solid state Cu deposition/dissolution at the surface of Mo6S8 particles. Moreover, the Mo6S8 and Cu mixture cathode improves the rate capability compared to the pristine. We believe that our finding will contribute to understanding the origin of the additional capacity of the Mo6S8 cathode arising from Cu addition and improve the electrochemical performance of the Mo6S8 cathode for rechargeable Mg batteries. © 2015 American Chemical Society.
Kim Y.,Korea Aerospace University |
Kim G.,Cheorwon Plasma Research Institute |
Lee S.,Korea Aerospace University
Journal of Nanoscience and Nanotechnology | Year: 2011
In this study, CrZrN films were synthesized by unbalanced magnetron sputtering (UBM) under various N 2 partial pressures and their characteristics such as crystalline structure, surface morphology, microstructure and mechanical properties as a function of the N 2 partial pressures were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), nanoindentation, wear tests, and corrosion tests. Results revealed that, with increasing the N 2 partial pressure from 0.05 to 0.21 Pa, the nitrogen content of the films increased from approximately 40.9 to 53.7 at%, the deposition rate decreased from approximately 100 to 59 nm/min and the surface roughness (Rms value) was increased from approximately 0.57 to 1.79 nm. The Cr 37.3-Zr 9.0-N 53.7 film has the highest hardness, elastic modulus, and plastic deformation resistance of 36 GPa, 380 GPa, and 0.41, respectively. The Cr 37.3-Zr 9.0-N 53.7 film also has the lowest friction coefficient and wear rate of 0.19 and 3.01 (10 -6m 3/Nm) at room temperature. In addition, the potentiodynamic test results showed the corrosion resistance of the CrZrN films became increased significantly and their corrosion current density (i corr), corrosion potentials (E corr) and corrosion rate decreased with increasing N 2 partial pressure. Copyright © 2011 American Scientific Publishers. All rights reserved.
Jung D.-U.,Chung - Ang University |
Yun Y.-I.,Cheorwon Plasma Research Institute |
Choi J.-S.,Chung - Ang University
IEEE Transactions on Consumer Electronics | Year: 2012
Foot interfacing has applications in games that require foot manipulation control using motion sensing devices. However, when part of a foot overlaps itself (selfocclusion), is out of the line of sight of the infrared sensor and it is then difficult to accurately capture foot pose. To overcome this problem, we propose a real-time motion sensing method based on 3-dimensional motion estimation. Our method employs pose parameters that are acquired using the ground plane and camera coordinates. This enables an assessment of the positions of the two joints that comprise a skeletal foot model. The proposed approach can capture a foot's 3-dimensional information that an infrared sensor may miss; therefore, motion sensing device's pose estimation results improve. According to the tracking and experimental results, the proposed method is applicable for use by motion sensing devices. © 2011 IEEE.
Cheng Y.,Tokyo Institute of Technology |
Tanaka M.,Tokyo Institute of Technology |
Watanabe T.,Tokyo Institute of Technology |
Watanabe T.,Kyushu University |
And 3 more authors.
Journal of Physics: Conference Series | Year: 2014
The catalyst of Ni2B nanoparticles was successfully prepared using nickel and boron as precursors with the quenching gas in radio frequency thermal plasmas. The generating of Ni2B needs adequate reaction temperature and boron content in precursors. The quenching gas is beneficial for the synthesis of Ni2B in RF thermal plasma. The effect of quenching rate, powder feed rate and boron content in feeding powders on the synthesis of nickel boride nanoparticles was studied in this research. The high mass fraction of 28 % of Ni2B nanoparticles can be generated at the fixed initial composition of Ni:B 2:3. Quenching gas is necessary in the synthesis of Ni2B nanoaprticles. In addition, the mass fraction of Ni2B increases with the increase of quenching gas flow rate and powder feed rate. © Published under licence by IOP Publishing Ltd.
Jeong D.S.,Kyung Hee University |
Choi W.S.,Kyung Hee University |
Choi W.S.,Cheorwon Plasma Research Institute |
Lee Y.T.,Kyung Hee University |
Ryu S.H.,Kyung Hee University
Polymer Engineering and Science | Year: 2014
The effect of montmorillonite and shear stress on the orientation of single walled carbon nanotubes and properties of SWCNT/MMT/polypropylene composite was investigated. The effect of functionalization of SWCNT on the orientation was also investigated. Polarized Raman spectroscopy was used to analyze the orientation of the SWCNTs. Orientation of SWCNTs was dependent on the experienced shear stress and functionalization of SWCNTs. The addition of MMT also improved the orientation of functionalized SWCNTs, while its effect was not significant for pristine SWCNTs. The existence of critical shear stress was observed for the orientation of the SWCNTs and the orientation of SWCNTs was found to occur more efficiently above this critical shear stress. Melt viscosity and heat of fusion data also confirmed that the addition of MMT-induced improved orientation and dispersion of SWCNTs, especially for functionalized SWCNTs. © 2013 Society of Plastics Engineers.
Kim S.-J.,Soongsil University |
Kim M.-C.,Soongsil University |
Han S.-B.,Soongsil University |
Lee G.-H.,Soongsil University |
And 6 more authors.
Nano Energy | Year: 2016
Despite extremely high capacity of Si-based anodes in lithium-ion batteries (LIB), Si-based materials have shown a structural collapse caused by a volumetric expansion/contraction during the cycling process. The conventional electrode structure, which consists of active materials, a current collector, a conducting agent, and a binder, actually showed a low loading of active material due to the other heavy components. In this study, we prepared a 3D flexible Si-composite electrode consisting of core (Si)-shell (Si3N4) NPs (Si@Si3N4) and carbon nanofibers (denoted as Si-composite/CNF). The Si-composite/CNF was directly utilized as an anode in the absence of the other components was electrochemically evaluated using a coin-type cell. The Si-composite/CNF showed a high capacity of 665 m Ah g−1 at a fairly high current density of 10 A g−1 and an extremely low capacity loss for 2000 cycles. © 2016
Cheorwon Plasma Research Institute | Date: 2013-12-24
The present invention relates to a graphene-nanoparticle composite having a structure in which nanoparticles are crystallized at a high density in a carbon-based material, for example, graphene, and, more particularly, to a graphene-nanoparticle composite capable of remarkably improving physical properties such as contact characteristics between basal planes of graphene and conductivity since nanoparticles are included as a large amount of 20 to 50% by weight, based on 100% by weight of graphene, and a method of preparing the same.
Cheorwon Plasma Research Institute | Date: 2014-12-23
The present invention relates to a nanometal-flake graphite composite and a method of manufacturing the same, and more particularly, to a nanometal-flake graphite composite, in which nanometal-flake graphite, in which crystallized nanometal particles are highly densely bonded to the surface of flake graphite, is coated with polydopamine to form a polydopamine coating layer which significantly improves properties such as bonding properties between flake graphite basal planes, adhesiveness with other media, and dispersibility, and a method of manufacturing the nanometal-flake graphite composite.
Cheorwon Plasma Research Institute | Date: 2013-12-27
The present invention relates to a graphene-nanoparticle composite having a structure in which nanoparticles are crystallized in a carbon-based material, for example, graphene, at a high density, and, more particularly, to a graphene-nanoparticle composite capable of remarkably improving physical properties such as contact characteristics between basal planes of graphene and conductivity, wherein nanoparticles are included as a large amount of 30% by weight or more, based on 100% by weight of graphene, and crystallized nanoparticles have an average particle diameter of 200 nm or more, and a method of preparing the same.
Cheorwon Plasma Research Institute | Date: 2012-09-12
An OLED lighting apparatus includes: an OLED light panel; a first electrode; a second electrode; and at least one resistor connected between the OLED light panel and at least one of the first and second electrodes; first sets of terminals on opposite sides of the module connected to the first and second electrodes; and second sets of terminals on opposite sides of the module, wherein the lighting circuit is connected in series between the first sets of terminals.