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101.
Masanori Usui Masayasu Ishiko Koji Hotta Satoshi Kuwano Masato Hashimoto 《Microelectronics Reliability》2005,45(9-11):1682
This paper describes the impacts of mechanical stress on vertical power devices. The stress dependence of the DC characteristics of trench insulated gate bipolar transistors (IGBTs) was measured. The experimental results could be reproduced by the device simulation, which included stress dependence models of the carrier mobility and the band gap. We found that the stress dependence of the on-state voltage mainly arose from the MOSFET portion of the IGBT. Using the device simulation, we estimated the effects of mechanical stress on the surge voltage and the saturation current, which give us the important information for designing a power module with higher ruggedness. 相似文献
102.
103.
In recent years, motor drive systems for steel rolling mills have been steadily increasing in capacity. In particular, the development of three‐level NPC (Neutral Point Clamped) inverters is now focusing on the replacement of cycloconverters. In order to satisfy such a requirement, in this paper a multiple three‐level NPC inverter system is proposed. The configuration consists of two three‐level NPC inverters with the same configuration connected in parallel by current limiting reactors. In this case, the circulating current flowing between the two three‐level NPC inverters must be controlled to prevent a decrease in the maximum output capacity. In particular, a new method for control of the circulating current is a major topic of discussion. The method is based on space voltage vector‐based PWM (Pulse Width Modulation) control for the three‐level NPC inverters and the circulating current is controlled by adjusting the output durations of the respective space voltage vectors. In this method the circulating current controller can be decoupled from the motor current controller. Therefore, it is possible to design the different controllers independently. In addition, the experimental results obtained using an induction motor show that the circulating current can be reduced to within 2% of the rated motor current when the motor current response exceeds 1000 rad/s. © 2001 Scripta Technica, Electr Eng Jpn, 136(2): 38–48, 2001 相似文献
104.
Atsushi Sano Masato Kurihara Kazuya Ogawa Tsuyoshi Iijima Satoshi Maruyama 《Journal of power sources》2009,192(2):703-707
The effect of alkali function group contained in electrode binder was investigated. Carboxy methyl cellulose (CMC) improved the initial irreversible capacity loss in graphite negative electrode. Lithium acetate also improved the initial cycle efficiency. On the other hand, ethyl cellulose (EC) and hydroxyl propyl methyl cellulose (HPMC), which do not have a carboxylic group, did not decrease the reductive electrolyte decomposition. After charge and discharge cycle, the surface film composition on the electrode with CMC was less than on the electrode without CMC. This suggests that a carboxylic group in the binder acted as a catalyst and promoted the solid electrolyte interphase (SEI) formation which prevents the excess electrolyte decomposition on the graphite electrode. 相似文献
105.
Eu-activated BaAl2 S4 (BaAl2 S4 :Eu) blue light emission phosphor has attracted considerable attention recently as a prospective material for full color electroluminescent display applications. Although BaAl2 S4 :Eu was discovered over 30 years ago, the solid-state reaction between metal sulfides in sealed quartz ampoules remains the main method for the synthesis of this material. In this work, a homogeneous single-phase Ba0.95 Eu0.05 Al2 S4 (BaAl2 S4 :Eu) phosphor was obtained by the sulfurization–reduction of the multicomponent oxide precursor in a CS2 atmosphere at 1050°C. The oxide precursor containing barium, aluminum, and europium for this process was prepared by the polymerizable complex method, which ensures a high degree of homogeneity in the final product. The BaAl2 S4 :Eu material thus obtained exhibited a single emission line at 475 nm and a fluorescence intensity of 35% compared with one of the best commercially available (Ba,Eu)MgAl10 O17 phosphors. 相似文献
106.
Hiroi Masato Hojo Masayuki Hashimoto Yukio Abe Yoshikazu Dote Yasuhiko 《Industrial Electronics, IEEE Transactions on》1986,(2):110-113
A methodology of discontinuous feedback and continuous feedforward control is developed to achieve accurate decoupled tracking in a class of nonlinear, time varying systems in the presence of disturbances, parameter variations and nonlinear dynamic interactions. The method is based on an improved variable structure control with a sliding mode. 相似文献
107.
Masato Yamamura Takatoshi NishioToshihisa Kajiwara Kitaro Adachi 《Chemical engineering science》2002,57(15):2901-2905
The ordered necklace-like or cellular pattern formation has been investigated for ternary polymer solutions in which primary and secondary phase separations were induced by the solvent evaporation. The patterns consisted of regular droplet arrays of various diameters, which arose in the pre-existing polymer phases via the secondary phase separation. The pattern formation was enhanced with increasing air velocity and ambient humidity, while it was suppressed with decreasing initial film thickness. The regular pattern was independent of surface wettability of the solid substrate. We ascribe the morphology change to the evaporation-induced surface tension driven convection, which re-arranged the droplet distributions from disordered to flow-induced ordered patterns. 相似文献
108.
This paper describes the fabrication of novel surface-mountable waveguide connectors and presents test results for them. To ensure more highly integrated and low-cost fabrication, we propose new three-dimensional (3-D) waveguide arrays that feature two-dimensionally integrated optical inputs/outputs and optical path redirection. A wafer-level stack and lamination process was used to fabricate the waveguide arrays. Vertical-cavity surface-emitting lasers (VCSELs) and photodiodes were directly mounted on the arrays and combined with mechanical transferable ferrule using active alignment. With the help of a flip-chip bonder, the waveguide connectors were mounted on a printed circuit board by solder bumps. Using mechanical transferable connectors, which can easily plug into the waveguide connectors, we obtained multi-gigabits-per-second transmission performance. 相似文献
109.
Mizuki Ono Tsunehiro Ino Masato Koyama Akira Takashima Akira Nishiyama 《Solid-state electronics》2004,48(12):2191-2198
It is shown that propagation delay time in CMIS (complementary metal insulator semiconductor field effect transistor) inverters is strongly affected by dielectric constant nonuniformity in gate dielectrics caused by the phase separation in silicate films. Influences of such nonuniformity on load capacitance are studied by analytical calculations based on a physical model which takes polarization into account. It is newly found that load capacitances are affected by the phase separation in qualitatively different ways, depending on the average metal concentration of their dielectric films. An experimental result is compared with those calculations. Influences of such nonuniformity on current drivability are studied by 3-dimensional device simulations. It is also newly found that such nonuniformity affects load capacitance and current drivability in different ways, resulting in an increase in propagation delay time of CMIS inverters for all metal concentrations studied. An explanation of this phenomenon is given with physical considerations. 相似文献
110.
Nao-Aki Noda Akifumi Inoue Masato Nagawa Fumitaka Shiraishi 《International Journal of Pressure Vessels and Piping》2002,79(12):807-818
This paper deals with a new seal system between flange joints without using a gasket. This gasketless flange includes a groove and an annular lip that is machined in one of the flange rings which when removed being in contact with the other flange to form a seal line when the flanges are assembled. In this study, firstly, fundamental dimensions are examined for unplasticized polyvinyl chloride (PVC-U JIS) to obtain the best sealing performance. Then, the effects of material difference and flange nominal size upon the sealing performance of the new gasketless flange are investigated for two types of materials, 0.25% carbon steel (S25C JIS) and PVC-U. It is found that the critical internal pressure at which leakage appears is mainly controlled by the maximum stress at the annular lip for each material even if the flange nominal sizes are different. The gasketless flange made by PVC-U shows the higher critical internal pressure compared with the case of S25C if the same clamping forces are applied. The effect of stress relaxation for PVC-U on the sealing performance is also considered. Then, it may be concluded that this PVC-U gasketless flange as well as S25C has good sealing performance. 相似文献