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排序方式: 共有399条查询结果,搜索用时 31 毫秒
21.
22.
Hiroyuki Moriuchi Yoshihiro Tadokoro Masahide Sato Takeshi Furusawa Noboru Suzuki 《Journal of Electronic Materials》2007,36(3):220-225
Lead-free commercial products have been dramatically increasing in the world markets as the restriction of certain hazardous
substances (RoHS) directive in the European Union has been enacted. At the same time, the problem of “tin whiskers” has become
one of the most serious problems in the industry. Growth of tin whiskers is believed to be related to residual stress inside
the tin plating film and external compressive stress. Whiskers in fine-pitch connectors have affected the practical production
of advanced digital equipment. The Japan Electronics and Information Technology Industries Association (JEITA) has proposed
a new testing method to evaluate tin whiskers, especially for the fine-pitch connectors. This paper describes the microstructures
of external stress whiskers and the mechanical indentation test method. 相似文献
23.
The effects of indium addition to CuAu on the alloy phase transformation behavior were investigated by hardness tests, electrical
resistivity measurements, X-ray diffraction and transmission electron microscopy. These established that indium additions
lower the critical temperature and stabilize the CuAu II phase at room temperature. Formation of the long period ordered phase
produces an age-hardening; although this age-hardening is retarded, the degree of hardening is comparable to that in CuAu.
It was noted that the axial ratio increases and the antiphase domain size decreases. 相似文献
24.
25.
Abnormal electric field appears at a wedgelike edge of a conductor (electrode) or a dielectric interface, which usually becomes infinitely high. This paper analyzes the electric field near such an edge by the analytical variable separation method and by the numerical one of the charge simulation method. The analysis focuses on the special conditions where the electric field becomes zero at an edge. These conditions are important for the insulation design to suppress the discharge inception at such edges of conductors and dielectric interfaces. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 1–8, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20280 相似文献
26.
Satoru Yamamoto Ryo Matsuzawa Takashi Furusawa 《American Institute of Chemical Engineers》2011,57(10):2629-2635
Axisymmetric nozzle flows with a free‐jet expansion are simulated considering several substances and several flow conditions, and the thermophysical properties in the nozzle and the free‐jet region are predicted. The present numerical method is based on the preconditioning method developed by Yamamoto and the mathematical models of thermophysical properties of the substances. As numerical examples show, gas flows of carbon dioxide, water, and nitrogen under a subcritical pressure condition are first calculated. Calculated distances to the Mach disk are compared with the experimental results, and also the density distributions are compared among these three substances. Second, carbon dioxide flows while changing the pressure from subcritical to supercritical values are calculated and the effect of pressure on the flow field is investigated. Third, flows of water vapor with and without nonequilibrium condensation are calculated and the effect of condensation on the flow field is investigated. © 2010 American Institute of Chemical Engineers AIChE J, 2011 相似文献
27.
Takaya Yamamoto Tomihiro Takano Yoshiyuki Takuma Makoto Inoue Gen Arao 《Electrical Engineering in Japan》2010,170(3):19-27
Dispersed generators such as wind power systems, photovoltaic systems, and cogeneration systems are expected to mitigate the environmental burden of energy consumption, and their installation has been promoted recently. Micro‐Grid is focused on as a method to solve some problems in a commercial electric power line when installing a large number of dispersed generators, and some demonstrative research on Micro‐Grid for large‐scale systems is being carried out now. Also, small cogeneration systems for houses, such as gas engines and fuel cells, are expected to improve CO2 emissions. However, if the power and heat demand of a family are relatively small or are unbalanced, the cogeneration system does not operate effectively. The authors have studied the application of Micro‐Grid for home energy supply, and have developed a control system to solve this problem. The system achieves a reduction of CO2 emissions and energy costs by sharing electric power and heat among some houses with cogeneration systems. This paper presents an outline of the newly developed system, and in particular describes the effect of the reduction in CO2 emissions compared with a conventional energy supply method, and the case in which dispersed generators are installed in some houses and operate independently. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(3): 19–27, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20879 相似文献
28.
Tadashi Kawamoto Tadasu Takuma Hisashi Goshima Hiroyuki Shinkai Hideo Fujinami 《Electrical Engineering in Japan》2009,167(1):1-8
This paper analyzes the electric field distribution near a wedge‐like edge in arrangements consisting of three dielectrics using analytical and numerical methods. The electric potential behaves exponentially as rn (r is the distance from the edge) near the edge, leading to an infinitely high field with decreasing r for all cases. The value of the analytically derived exponent n agreed well with that obtained from the numerical field calculations. It has also been demonstrated that rounded contact of the spacer with a zero contact angle can make the electric field constant without showing an exponential rise near the edge. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 1– 8, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20670 相似文献
29.
Mototsugu Takemoto Takuma Karasawa Hiroshi Mizumachi Mikio Kajiyama 《The Journal of Adhesion》2013,89(1):85-96
A series of ethylene vinyl acetate copolymer (EVA) were blended with various kinds of tackifiers and the miscibility between the components was investigated. The miscibility of the blend is illustrated as a phase diagram. The EVA and modified rosin systems tended to have a phase diagram with lower critical solution temperature (LCST), whereas the EVA and petroleum resin systems tended to have that with upper critical solution temperature (UCST). The phase diagrams of EVA/tackifier resins systematically changed as VAc content in the copolymer increased, which is accounted for by the classical Flory-Huggins theory. 相似文献
30.
The authors have developed an experimental
in HDTV digital videocassette recorder (VCR). The VCR can record HDTV digital base-band signals for more than 64 min on a
in metal particle (MP) tape. An eight-to-eight modulation (
) scheme has been developed for this VCR to realize high-density recording. In order to suppress sufficiently the low-frequency components and reduce the occurrence probability of long-run-lengths for the recording data sequence, a new conversion table and bit-rearrangement method have been introduced in this modulation scheme. This conversion table has been particularly structured to reduce run-length using the bit-rearrangement process. Three kinds of typical HDTV images were used to evaluate the performance compared with the scrambled-NRZ method. The run-length distribution and the frequency spectrum were calculated for each image. The results showed that the occurrence probability of long-run-lengths were well reduced and the low-frequency components along with the DC component were sufficiently suppressed. Cross-talk interferences and overwriting noises were also found to be much less than those for the scrambled-NRZ method. 相似文献