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991.
Min Ho Kim Yun Chan Kang Sang Mun Jeong Yun Ju Choi Yang Soo Kim 《Materials Chemistry and Physics》2013
Nanosized 0.6Li2MnO3·0.4LiCoO2 composite cathode powders are prepared by spray pyrolysis. The micron-sized composite powders are converted into nanosized powders by a simple milling process. The mean sizes of the composite powders measured from the TEM images increase from 20 to 170 nm when the post-treatment temperatures increase from 650 to 900 °C. The Brunauer–Emmett–Teller surface areas of the composite powders post-treated at 650 and 900 °C are 24 and 3 m2 g−1, respectively. The XRD patterns indicate that the layered composite powders post-treated at 800 and 900 °C have high crystallinity and low cation mixing. The mean crystallite sizes of the powders, measured from the (003) peak widths of the XRD patterns using Scherrer's equation, are 35 and 56 nm at post-treatment temperatures of 800 and 900 °C, respectively. The initial discharge capacities of the 0.6Li2MnO3·0.4LiCoO2 composite are 262, 267, 264, and 263 mAh g−1 when the post-treat temperatures of the powders are 650, 700, 800, and 900 °C, respectively. The discharge capacity of the composite powders post-treated at 900 °C abruptly decreases from 263 to 214 mAh g−1 by the seventh cycle and then slowly decreases to 198 mAh g−1 with increasing cycle number, up to 30. 相似文献
992.
Paula Brown Richard Jay Andrea Fox Matthew Oliver 《Hemodialysis international. International Symposium on Home Hemodialysis》2013,17(3):444-449
Heparin‐induced thrombocytopenia (HIT) is a potentially life‐threatening condition that can develop after exposure to unfractionated or low–molecular‐weight heparins. Treatment options appear to be limited in patients on concurrent intermittent hemodialysis. We report the case of an 88‐year‐old man newly initiated on high‐flux hemodialysis who developed HIT and extracorporeal circuit thrombosis after 3 weeks of exposure to unfractionated heparin. Our patient was successfully treated with fondaparinux 2.5 mg subcutaneously three times per week and citrate during dialysis sessions. Antifactor Xa levels were measured on several occasions while receiving fondaparinux. 相似文献
993.
Jaemin Lee Inhwa Lee Taek‐Soo Kim Jung‐Yong Lee 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(17):2887-2894
Silver nanowire (AgNW) random meshes have attracted considerable attention as flexible and high‐performance transparent electrodes. Notably, post‐treatment of the AgNW random meshes, such as thermal annealing, is usually required to guarantee comparable optical transparency and electrical conductivity to commercial indium tin oxide (ITO). Here, the integral elements of preparing a high‐performance, large‐area AgNW random mesh network are discussed. High‐performance nanostructured transparent electrodes can be obtained without any post‐treatment, thereby relieving the restrictions related to the substrate. Solvent washing and a large‐area spray‐coating method effectively reduce the wire–wire contact resistances, thus reducing or eliminating the requirement for post‐treatment. 相似文献
994.
995.
Jongwon Yoon Woojin Park Ga‐Yeong Bae Yonghun Kim Hun Soo Jang Yujun Hyun Sung Kwan Lim Yung Ho Kahng Woong‐Ki Hong Byoung Hun Lee Heung Cho Ko 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(19):3295-3300
A highly flexible and transparent transistor is developed based on an exfoliated MoS2 channel and CVD‐grown graphene source/drain electrodes. Introducing the 2D nanomaterials provides a high mechanical flexibility, optical transmittance (~74%), and current on/off ratio (>104) with an average field effect mobility of ~4.7 cm2 V?1 s?1, all of which cannot be achieved by other transistors consisting of a MoS2 active channel/metal electrodes or graphene channel/graphene electrodes. In particular, a low Schottky barrier (~22 meV) forms at the MoS2/graphene interface, which is comparable to the MoS2/metal interface. The high stability in electronic performance of the devices upon bending up to ±2.2 mm in compressive and tensile modes, and the ability to recover electrical properties after degradation upon annealing, reveal the efficacy of using 2D materials for creating highly flexible and transparent devices. 相似文献
996.
Jeong Hoon Seo Kyung Don Baik Dong Kyu Kim Seonyeob Kim Jong Won Choi Mansu Kim Han Ho Song Min Soo Kim 《International Journal of Hydrogen Energy》2013
The effects of anisotropic bending stiffness of a gas diffusion layer (GDL) on membrane electrode assembly (MEA) degradation were investigated. We prepared GDLs with a fiber direction perpendicular to the major flow (i.e., “90° GDL”) and with a fiber direction parallel to the major flow (i.e., “0° GDL”). To analyze the mechanical durability as a function of GDL anisotropy, we examined cell performances such as the I–V characteristics and impedances and the hydrogen crossover characteristics during wet/dry cycles. The results showed that the 90° GDL fuel cell is superior to the 0° GDL fuel cell in terms of higher I–V performance, lower resistance at high frequency, and lower hydrogen crossover through the MEA. Mechanical degradation of the 0° GDL was investigated using scanning electron microscopy (SEM). 相似文献
997.
Sung Il Kim Kyung Don Baik Beom Jun Kim Nam Woo Lee Min Soo Kim 《International Journal of Hydrogen Energy》2013
Severe flooding can be critical in a fuel cell vehicle operating at a high current density, and in a fuel cell vehicle at the initial stage of start up. It is often difficult to remove the condensed water from the cathode gas diffusion layer (GDL) of the fuel cell because of the surface tension between the water and the GDL. In this research, in order to remove the condensed water from the cathode GDL, a small amount of hydrogen was injected into the cathode reactant gases. The results showed that the hydrogen addition method successfully removed the liquid water from the cathode GDL. Water removal was verified for various hydrogen flow rates and hydrogen addition durations. Furthermore, the dew point temperature of the outlet gas at the cathode was observed to determine the amount of water removed from the cathode GDL. In addition, the water droplet in the cathode gas flow channel was visualized by using a transparent cell. Furthermore, degradation tests are also performed. Considering the degradation test, the hydrogen addition method is expected to be effective in mitigating cathode flooding. 相似文献
998.
999.
David K. Aspinwall Andrew L. Mantle Wai Kok Chan Richard Hood Sein Leung Soo 《CIRP Annals》2013,62(1):75-78
Experimental results are presented for Ti–45Al–2Mn–2Nb + 0.8 vol% TiB2XD and Ti–45Al–8Nb–0.2C alloys. Three approaches were employed involving a constantan-workpiece thermocouple arrangement, implanted K-type thermocouples and IR thermography. New and worn (~300 μm flank wear) coated carbide tools were used under dry conditions when down milling at 50–345 m/min, with workpieces mounted horizontally and at 45°. Despite slight variation in ancillary finishing parameters there was generally good agreement between data sets for the different evaluation techniques employed and for both alloys. Higher temperatures were measured with the workpiece at 45°, with constantan-workpiece thermocouple temperatures of 375 °C and 413 °C for new and worn tools respectively at 345 m/min. 相似文献
1000.
Nickel-titanium diboride (Ni-TiB2) composite coatings were successfully fabricated by pulse electrodeposition techniques from nickel sulfamate bath containing dispersed submicron TiB2 particles. The effect of TiB2 codeposition on the morphological, microstructural, microhardness and anti-corrosive properties of the composite coatings have been investigated by using scanning electron microscopy coupled with energy dispersive spectroscopy system, X-ray diffraction (XRD), vickers microhardness, and electrochemical impedance spectroscopy (EIS) techniques. Incorporation of TiB2 particles into the nickel matrix has modified the regular crystal growth of nickel. The XRD patterns revealed that the preferred (100) crystallite orientation of pure nickel has been modified into mixed orientations by the enhancement of (111) and attenuation of (200) diffraction intensities by the incorporation of TiB2 particles into the nickel matrix. Vickers microhardness of the Ni-TiB2 composite coating is found to be increased which is nearly 3 times higher than pure nickel coating. The results obtained by polarization curves and EIS analysis in 3.5 wt% NaCl solution have shown the improved corrosion resistance properties of Ni-TiB2 composite coating over pure nickel electrodeposit. 相似文献