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排序方式: 共有273条查询结果,搜索用时 15 毫秒
71.
72.
Himei Toyoji Inouye Jyunichi Nakanishi Senichiro Ukita Isamu 《Industry Applications, IEEE Transactions on》1975,(5):531-539
A circuit controlled by thyristors and having series RLC elements gives rise to a step-up phenomenon. The term step-up is defined with respect to the capacitance voltage on steady state operation, i.e., the ratio of the maximum peak value when controlled by thyristers to the peak amplitude when thyristors are short-circuited exceeds unity. The domain of possible step-up voltage is determined by the angle of displacement between current and voltage and damping factor. The step-up voltages appear across each element, i.e., not only across the capacitance, inductance, and resistance but also across the thyristors. The control characteristic has a distinctive hump phenomenon. The interrupted current results in waveform distortion, phase lag, and improved power factor. The difference of characteristics between the peak and rms values of voltages, particularly of inductance and thyristors, is large. The response time, which is evaluated by numbers of half cycles, is large when the step-up ratio becomes large. The output voltage when the circuit is used as a voltage source has a drooping characteristic. 相似文献
73.
Mamoru Mitomo Yoh-ichiro Sato Nobuo Ayuzawa Isamu Yashima 《Journal of the American Ceramic Society》1991,74(4):856-858
Plasma etching of β-Si3 N4 , α-sialon/β-Si3 N4 and α-sialon ceramics were performed with hydrogen glow plasma at 600°C for 10 h. The preferential etching of β-Si3 N4 grains was observed. The etching rate of α-sialon grains and of the grain-boundary glassy phase was distinctly lower than that of β-Si3 N4 grains. The size, shape, and distribution of β-Si3 N4 grains in the α-sialon/β-Si3 N4 composite ceramics were revealed by the present method. 相似文献
74.
The effect of siloxane chain length on surface segregation of poly(methyl methacrylate)‐grafted poly(dimethyl siloxane) (PMMA‐g‐PDMS)/poly(2‐ethylhexyl acrylate‐co‐acrylic acid‐co‐vinyl acetate) [P(2EHA‐AA‐VAc)] blends was investigated. The blends of PMMA‐g‐PDMS with P(2EHA‐AA‐VAc) showed surface segregations of PDMS components. The surface enrichments of PDMS in the blends depended significantly on the PDMS chain length. Also, this blend showed the gradient domain structure. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 375–380, 2003 相似文献
75.
Hideo Sawada Hitomi Horiuchi Tokuzo Kawase Kazuya Oharu Hideki Nakagawa Isamu Kaneda 《应用聚合物科学杂志》2005,96(4):1467-1476
Fluoroalkyl end‐capped cooligomers containing polydimethylsiloxane and polyoxyethylene segments were prepared under very mild conditions by the cooligomerizations of fluoroalkanoyl peroxides with methacrylate monomers containing the corresponding segments and comonomers such as dimethylacrylamide and acryloylmorpholine. These obtained fluorinated cooligomers exhibited amphipathic characteristics and became soluble in water and common organic solvents. In particular interest, fluoroalkyl end‐capped cooligomers containing polyoxyethylene units were soluble not only in poly(methylphenylsiloxane) (silicone oil) but also in water, including common organic solvents except for hexane. Additionally, these fluorinated cooligomers were able to reduce the surface tension of water and m‐xylene quite effectively, to around 15 and 20 mN/m levels, respectively. In these fluorinated cooligomers, fluoroalkyl end‐capped acryloylmorpholine cooligomers containing polyoxyethylene segments were applicable as a novel emulsifying agent against water and silicone oil. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1467–1476, 2005 相似文献
76.
Itsuo Ohnaka Isamu Yamauchi Satoru Kawamoto Tatsuichi Fukusako 《Journal of Materials Science》1985,20(6):2148-2158
Rapidly solidified Al-4.5 wt% Cu powder was produced by the rotating-water-atomization process recently developed by the authors. The particles were not spherical but tear-drop shape. The mean particle size of the powder decreased with increasing rotational speed of the drum and with decreasing nozzle diameter. The dendrite arm spacing of the particles produced was in the range 0.6 to 2.8m. The cooling rate was estimated to range from 103 to 5×105 K sec–1. Recrystallization of hot extruded powder material after T6 treatment was remarkably suppressed in the central part, while large fully recrystallized grains were obtained in the cast material extruded under the same conditions. Tensile strength of the powdered material extruded in the range 573 to 723 K was slightly higher than the extruded cast material with little loss in elongation. The surface oxidation was not deleterious to elongation but it was very effective in suppressing recrystallization. 相似文献
77.
Kato Isamu Terumichi Yoshiaki Adachi Masahito Sogabe Kiyoshi 《Journal of Mechanical Science and Technology》2005,19(1):328-335
For high speed railway vehicles, we consider a vibiation of flexible track/wheel system It is very important to deal with the complex phenomena of high-speed vehicles that can be occurred in the vertical vibration of the system From a viewpoint of multibody dynamics, this kind of problem needs accurate analysis because the system includes mutual dynamic behaviors of rigid body and flexible body The simulation technique for the complex problems is also discussed We consider the high-speed translation, rail elasticity, elastic supports under the rail and contact rigidity Eigen value analysis is also completed to verify the mechanism of the coupled vertical vibration of the system 相似文献
78.
Isamu Saito 《Water research》1984,18(3):319-323
The removal of iron cyano-complex ions [hexacyanoferrate(II) and (III) ions] in a dilute aqueous solution by activated carbon was investigated. The maximum adsorption of iron cyano-complex ions on activated carbon occurred at pH around 3. The hexacyanoferrate(III) ion was more adsorbable than the hexacyanoferrate(II) ion. Activated carbon promoted the oxidation of hexacyanoferrate(II) ion to (III) ion with dissolved oxygen in an acidic solution and the reduction of hexacyanoferrate(III) ion to (II) ion in an alkaline solution. The iron cyano-complex ion adsorbed on activated carbon could be eluted with higher concentrated acidic and alkaline solutions. The degree of elution decreased with an increase in potassium hydroxide concentration, since parts of the iron cyano-complexes on activated carbon were decomposed to form the iron hydroxide and the hexacyanoferrate(II) ion with an alkaline solution. The behavior of iron cyano-complexes in the presence of activated carbon, in the lower pH range (pH < 1) and at higher temperatures (80°C), was discussed. 相似文献
79.
Saburo Akiyama Nikako Tsukiji Isamu Akiba Minoru Inoue Yoshihisa Kano 《Polymer International》2001,50(6):659-662
The relationship between the surface composition and the rate of solvent evaporation (R) in blend films of poly(vinylidene fluoride‐co‐hexafluoroacetone) (P(VDF‐HFA)) and poly(2‐ethylhexyl acrylate‐co‐acrylic acid‐co‐vinyl acetate) (P(2EHA‐AA‐VAc)) has been investigated. P(VDF‐HFA), a low‐surface tension component, was concentrated on the surface when R was relatively high. In contrast, when R was relatively low, P(2EHA‐AA‐VAc), a low‐density component, was concentrated on the surface. Therefore, it is speculated that the factors dominating surface enrichment in polymer blends were changed from surface tension differences to density differences between the components when R was decreased. In addition, the affinity between components and substrate strongly affects the dominant factors determining the surface composition. © 2001 Society of Chemical Industry 相似文献
80.
We performed a series of molecular dynamics (MD) simulations on Nafion® membranes containing various quantities of H2O and CH3OH. The simulations afforded diverse nanoscale phase-separated structures, such as clusters, channels, and cluster–channels. The calculated cluster–channel structure qualitatively agrees with the experimental results of X-ray diffraction studies. We also investigated the diffusion mechanisms for H2O, protons, CH3OH, H2, and O2 in these membranes. To reproduce the hopping transfer of protons, we employed a semi-classical MD approach using the empirical valence bond method. The estimated diffusion coefficients of H2O and proton in the membranes significantly depended on the H2O content, and these values showed qualitatively good agreement with the experimental results. The diffusion coefficient of proton in H2O-rich membranes was much larger than that of H2O, and the proton mainly formed H5O2+ complex. Furthermore, the simulation results indicate that the majority of CH3OH permeates through the H2O clusters, and the majority of H2 and O2 permeates through the hydrophobic region of the membrane. 相似文献