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排序方式: 共有1472条查询结果,搜索用时 15 毫秒
101.
Vilmos Galamb Sang Chul Shim Fazle Sibtain Howard Alper 《Israel journal of chemistry》1985,26(3):216-218
The intermediates mentioned in the title are probably involved in the hydrogenation of olefins and dienes; bidentate phosphine and arsine cobalt complexes are useful reagents for these reactions. 相似文献
102.
Jaewon Choi Jeongwoo Lee Jinsub Choi Dongsoo Jung Sang Eun Shim 《Synthetic Metals》2010,160(13-14):1415-1421
Herein, PEDOT:PSS/PVP nanofibers were produced by electrospinning. The presence of PEDOT:PSS in the nanofibers was confirmed by FT-Raman spectroscopy. The applied voltage-dependent diameter of PEDOT:PSS/PVP nanofibers was observed. Also, sensing behaviors of electrospun PEDOT:PSS/PVP nanofibers were explored by measuring its response upon cyclic exposure to organic vapours such as ethanol, methanol, THF, and acetone at room temperature. When PEDOT:PSS/PVP nanofibers were exposed to each solvent, the protic and aprotic solvents resulted in opposite electrical responses. These findings exhibit that electrospun PEDOT:PSS/PVP nanofibers are the promising candidate for the organic vapour sensing material. 相似文献
103.
Jong Duk Lee Byung Chang Shim Hyung Soo Uh Byung-Gook Park 《Electron Device Letters, IEEE》1999,20(5):215-218
This letter reports the surface morphology and current-voltage (I-V) characteristics of single-crystal silicon (c-Si), polycrystalline silicon (poly-Si), and amorphous silicon (a-Si) field emitter arrays (FEAs). As-deposited a-Si film has a smoother surface than poly-Si film. The surface morphology of the a-Si remains smooth even after phosphorus doping and oxidation at 950°C to be improved in emission characteristics, i.e., smaller anode current deviation among arrays smaller gate current, and higher failure voltage than those of poly-Si FEAs. Such improved characteristics can be explained by the smooth surface morphology which is kept during doping and oxidation. The surface roughness and emission characteristics of a-Si FEAs are comparable to those of c-Si FEAs 相似文献
104.
Gyu Bo Kim Jae Young Shim Seung Wan Cho Young June Chang Chung Hwan Jeon 《Journal of Mechanical Science and Technology》2008,22(6):1154-1162
With environmental concerns over emitted particulate matters(PM) from combustion systems, various researches have been conducted
on reduction and measurement techniques of particulate matters. The LII analysis results from numerical models and experiments
in an ethylene/air laminar diffusion flame at elevated pressure up to 2.0 MPa with laser fluence 0.07 J/cm2, detection wavelength 400 nm were compared to validate a modified LII numerical model. The lifetime of the LII signal decreased
as the elevated pressure increased, so that LII decay time also decreased in both results. In the aspect of heat transfer
mechanism, it becomes earlier that dominant conduction starts. This shows that the results matched well under the pressure
conditions. It is concluded that the LII numerical model could be applied to decide particle size in TIRE-LII at the high-pressure
condition. 相似文献
105.
Yuvaraj Haldorai Won Seok Lyoo Seok Kyun Noh Jae-Jin Shim 《Reactive and Functional Polymers》2010,70(7):393-399
This report describes the novel preparation of silica/polystyrene (SiO2/PS) core–shell composite nanospheres by in situ radical dispersion polymerization in an ionic liquid (IL). Silica nanoparticles were first surface modified by the silane coupling agent methacryloxypropyltrimethoxysilane (MPTMS), which is capable of copolymerizing with styrene and provided a reactive CC bond. Transmission electron microscopy (TEM) revealed core–shell morphology with smooth surfaces. X-ray photoelectron spectroscopy (XPS) analysis demonstrated that almost all of the SiO2 nanoparticles were encapsulated by the polymer. The composite particles were also analyzed by FT-IR spectroscopy and thermogravimetric analysis (TGA). In principle, this simple and environmentally-friendly synthetic procedure can be employed to prepare other inorganic oxide-containing polymer composites. 相似文献
106.
A 2-D device simulation for organic thin-film transistors (OTFTs) was carried out to reveal the characteristic difference between staggered and planar structures. Assuming the OTFT with Schottky barrier contact, the staggered-structure TFT has more current flow, bigger field-effect mobility, and lower contact resistance than the planar structure. The simulation results indicate that the source electrode of the staggered structure has better ability to supply the current than that of the planar structure. 相似文献
107.
M. Shamshi Hassan M. Shaheer Akhtar Kyung-Bo Shim O-Bong Yang 《Nanoscale research letters》2010,5(4):735-740
Highly crystalline Pr6O11 nanorods were prepared by a simple precipitation method of triethylamine complex at 500°C. Synthesized Pr6O11 nanorods were uniformly grown with the diameter of 12–15 nm and the length of 100–150 nm without any impurities of unstable
PrO2 phase. The Pr6O11 nanorod electrodes attained a high electrical conductivity of 0.954 Scm−1 with low activation energy of 0.594 eV at 850°C. The electrochemical impedance study showed that the resistance of electrode
was significantly decreased at high temperature, which resulted from its high conductivity and low activation energy. The
reduced impedance and high electrical conductivity of Pr6O11 nanorod electrodes are attributed to the reduction of grain boundaries and high space charge width. 相似文献
108.
Seungho Kim Woon Jin Chung Somi Jung Gyuin Shim Huiyeon Shon Seung Kim Kyeong Dae Park 《Journal of the American Ceramic Society》2023,106(1):569-581
The fracture mechanism of a chemically strengthened ultrathin glass (UTG) for the cover window of flexible display devices was investigated under pen loading conditions for the first time to better understand the UTG impact resistance characteristics. High-speed camera analysis, fracture fragment analysis, and finite element modeling were employed to investigate the fracture mechanism of the UTG under pen drop conditions. A pen-on-plate (POP) test was also employed to examine the fracture characteristics under static loading condition, and its results were compared with those of the pen drop test (PDT) to find a correlation between the static and dynamic loading conditions. The correlation found between the POP and PDT tests indicates that a quantitative estimation of contact displacement under PDT can be obtained by measuring the first ring crack size, to more easily determine the impact resistance characteristics of UTG. 相似文献
109.
Jae-Sung Oh Min-Chul Shim Man-Ho Park Kee-Ahn Lee 《Metals and Materials International》2014,20(5):915-921
This study investigated the high temperature oxidation behavior of newly developed Ni-Cr-Al powder porous metal. High temperature isothermal oxidation tests were conducted at 900, 1000 and 1100 °C temperatures for 24 h under an atmosphere of 79% N2 + 21% O2 gas. Oxidation weight gain vs. time curves represented typical oxidation behavior of parabolic shape. Weight gain increased with increasing oxidation temperature. Ni-Cr-Al porous metal mainly created oxides such as α-Al203, Cr2O3, NiCr2O4. The α-Al203 oxide could be still maintained up to 1100 °C oxidation temperature as a thick and stable protective layer. It was noted that Ni-Cr-Al porous metal had better high temperature oxidation resistance than those of other Ni-based and Fe-based porous metals. The catastrophic degradation of oxidation resistance especially at very high temperature was not observed up to 1100 °C in this porous metal. The micro-mechanism of high temperature oxidation of Ni-Cr-Al porous metal was also discussed. 相似文献
110.
Herein, we fabricated MWCNT–OH adsorbed electrospun nylon 6,6 nanofibers by electrospinning and dip coating method. The amount of MWCNT–OH adsorbed to the pure electrospun nylon 6,6 nanofibers was 0.056 wt%. The electrical conductivity of MWCNT–OH adsorbed electrospun nylon 6,6 nanofibers was 5.24 × 10?3 S cm?1. We also investigated the sensing properties of MWCNT–OH adsorbed electrospun nylon 6,6 nanofibers by measuring its response upon exposure to low molecular weight alcohol vapours such as methanol, ethanol, 1-propanol, and 1-butanol. The changes of the electrical resistance of MWCNT–OH adsorbed electrospun nylon 6,6 nanofibers were demonstrated on the basis of hydrogen bonds among the alcohol vapours and hydroxyl groups (–OH) on MWCNT–OH, and amide groups (–NHCO–) in nylon 6,6. The fabricated sensor showed good reversible and reproducible responses upon the cyclic test. 相似文献