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1.
With the advancement of high‐frequency switching devices, electromagnetic interferences (EMI) have become problems in power electronic converter designs. It is necessary for an electromagnetic compatibility (EMC) design to prospect and consider its possible EMI levels. This paper describes how to compute effects from a power converter to an object point to reduce conduction EMI noises effectively by an appropriate design. Modeling techniques for converter elements are discussed for a model in the conduction emission frequency band by the parameter tuning method and for line constants by an analytical derivation. Then a derived model is simulated for harmonic distributions of loop currents and their magnetic fields. © 2002 Scripta Technica, Electr Eng Jpn, 139(1): 44–50, 2002: DOI 10.1002/eej.1145 相似文献
2.
3.
S. Ohba N. Akahane T. Wakabayashi T. Nakahara T. Yokochi K. Yanagi N. Ohshima 《Lipids》1997,32(6):593-598
The dietary effect of 1,3-biseicosapentaenoyl-2-γ-linolenoyl glycerol (STG) on the fatty acid composition of guinea pigs was
examined and compared with that of an eicosapentaenoic acid ethyl ester (EPA-F) and of a soybean oil (SBO) diet. In terms
of content of plasma lipid, EPA-E had a greater hypolipidemic effect than STG. On the other hand, in terms of EPA incorporation,
contents of EPA in liver lipid were almost the same in the STG and EPA-E groups. Considering that the amount of EPA administered
in the EPA-E group was almost 1.5 times that of the STG group, FPA may be absorbed more effectively as the glycerol ester
than as the ethyl ester in guinea pigs. In all the tissue lipids, the STG group had a higher unsaturation index (UI) than
the EPA-E group even though there is a lower UI in the STG diet than the EPA-E diet. These results suggest that greater amounts
of desaturase products as a whole were synthesized in the STG group than in the other two groups. The dihomo-γ-linolenic acid/arachidonic
acid (DGLA/AA) ratio in plasma total lipids in the STG group was 3.5 times that of SBO group, and the DGLA/AA ratio in the
EPA-E group was half that of the SBO group. In liver lipid, the ratios of DGLA/AA and EPA/AA in the STG group were 0.687 and
0.488 (phosphatidylcholine fraction) and 0.237 and 0.752 (phosphatidylethanolamine fraction), respectively. The ratio of DGLA/AA
as well as the high EPA/AA ratio obtained in the present study with the STG diet may lead to physiological alterations, including
enhanced synthesis of 1-and 3-series eicosanoids. 相似文献
4.
Hidehiko Kobayashi Kenichi Shimosaka Miki Saitoh Takashi Mitamura 《Journal of the American Ceramic Society》1993,76(9):2389-2392
We investigated the conditions for low-temperature synthesis of ZrC fine powder from ZrO2 –Mg–CH4 . The synthesis utilizes a thermite-type reaction, with Mg as the reducing agent, and a reaction between Mg and CH4 gas as a carbon source. The Mg/ZrO2 molar ratio as well as the heating rate were varied. Because C can be continuously fed into the reaction group by the cyclic reaction of Mg through the formation and decomposition of Mg2 C3 (2Mg + 3CH4 → Mg2 C3 + 6H2 → 2Mg + 3C), a molar ratio of 2.2 for Mg/ZrO2 was sufficient for the synthesis of single-phase ZrC. ZrC powders were synthesized under the following conditions: Mg/ZrO2 molar ratio = 2.2, heating rate = 20°C/min, and temperature maintained at 750°C for 30 min. The amount of reaction heat produced in the reduction reaction of ZrO2 by Mg depended on the Mg/ZrO2 molar ratio, specifically, the amount of ZrO2 contained. Moreover, the cyclic reaction of Mg-Mg2 C3 –Mg was influenced by the amount of reaction heat described above and by the heating rate. The ZrC fine powder showed little aggregation and high dispersibility. 相似文献
5.
Satoshi Nakata Kenichi Yoshikawa Osamu Shima Hiroshi Terada 《Advanced functional materials》1992,1(6):281-286
A new chemical sensing system using an electrical oscillator has been developed. This sensing system measures the electrical ‘non-linearity’ at the surface of an electrode immersed in a test solution: a sinusoidal voltage is applied to the electrode and the higher harmonics of the output current are obtained by Fourier transformation. This sensing system has been used to detect and quantify surfactant molecules in solutions. The relative intensity P2/P1 of the peaks of the second (P2) and first (P1) harmonics in the output current was found to be linearly correlated with the logarithms of the concentrations of cationic surfactants such as cetylpyridium bromide (CPB) and cetyl-N,N,N-trimethylammonium bromide (CTAB), but not with those of the anionic surfactant sodium dodecyl sulfate (SDS) or the neutral surfactant Triton X-100. The reproducibility of this sensing system was shown to be excellent. 相似文献
6.
Chen H. W. Yanagi K. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2006,52(5):2167-2172
In this correspondence, we give several inherent properties of the capacity function of a Gaussian channel with and without feedback by using some operator inequalities and matrix analysis. We give a new proof method which is different from the method appearing in: K. Yanagi and H. W. Chen, "Operator inequality and its application to information theory," Taiwanese J. Math., vol. 4, no. 3, pp. 407-416, Sep. 2000. We obtain the following results: C/sub n,Z/(P) and C/sub n,FB,Z/(P) are both concave functions of P, C/sub n,Z/(P) is a convex function of the noise covariance matrix and C/sub n,FB,Z/(P) is a convex-like function of the noise covariance matrix. This new proof method is very elementary and the results shall help study the capacity of Gaussian channel. Finally, we state a conjecture concerning the convexity of C/sub n,FB,/spl middot//(P). 相似文献
7.
Multiwalled carbon nanotubes on which poly(cyclohexyl methacrylate)s are densely grafted (PCHMA‐CNTs), are synthesized using a modified surface‐initiated atom transfer radical polymerization technique. The electrical resistance of PCHMA‐CNT is systematically characterized under direct current (DC) and alternating current and compared to that of conventional nanocomposites prepared by blending PCHMA with the CNT (PCHMA/CNT). At a comparable volume fraction of CNT, DC volume resistivity of PCHMA‐CNT is 14 orders of magnitude higher than that of PCHMA/CNT. This is because the grafted polymer with a combination of the high molecular weight and the high grafting density isolates individual CNTs at a long distance in the PCHMA‐CNT system. In addition, impedance analysis reveals that the highly insulated PCHMA‐CNT has the same electrical nature as neat PCHMA, i.e., it is a dielectric. Furthermore, dynamic mechanical analysis shows PCHMA‐CNT has a good mechanical properties as well as ultrahigh electrical resistance. 相似文献
8.
Shuto Y. Yanagi S. Asakawa S. Kobayashi M. Nagase R. 《Quantum Electronics, IEEE Journal of》2004,40(8):1113-1121
The unsteady-state thermal conduction process in step-index single-mode (SM) optical fiber was studied theoretically with the explicit finite-difference method. We considered a high-temperature loss-increase mechanism, which includes two factors that bring about an increase in the absorption coefficients: 1) electronic conductivity due to the thermal ionization of a Ge-doped silica core and 2) thermochemical SiO production in silica glass. The core-center temperature changed suddenly and reached over 4/spl times/10/sup 5/ K when a 1.064-/spl mu/m laser power of 2 W was input into the core layer heated at 2723 K. This rapid heating of the core initiated the "fiber fuse" phenomenon. The high-temperature core areas were enlarged and propagated toward the light source. The propagation rates of the fiber fuse, estimated at 1.064 and 1.48 /spl mu/m, were in fair agreement with the experimentally determined values. We found that the threshold power for initiating the fiber fuse increases from 0.98 to 1.26 W when the input laser wavelength is increased from 1.06 to 1.55 /spl mu/m. 相似文献
9.
Kenichi Kikuchi Yasunori Fujii 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(10):1205-1211
Performances of 640-GHz Superconductor–Insulator–Superconductor (SIS) mixers developed for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) mission are described. SMILES, launched in September 2009, is the first mission to observe atmosphere from space using superconducting mixers. Ground test performances of the SIS mixers show very flat gain and noise characteristics in their observation bands in compliance with the specifications required for SMILES. 相似文献
10.
Yoshihiro Ichikawa Shigeki Obote Kenichi Kagoshima 《Wireless Personal Communications》2005,35(4):353-364
A tapped delayed line adaptive array antenna (TDL-AAA) and a space-temporal simultaneous processing equalizer (ST-SPE) are
proposed as simple space-temporal equalizers based on minimum mean square error (MMSE) criterion. The ST-SPE has a compact
hardware with a small number of taps compared to that of the TDL-AAA. The ST-SPE can reduce the computational complexity of
the space-temporal joint equalization and it works effectively under the minimum phase condition such as appeared at line-of-sight
(LOS) propagation environments at a high antenna height base station. However the ST-SPE cannot work under a non-minimum phase
condition caused under N-LOS (non-line-of-sight). On the other hand, the TDL-AAA whose reference signal is synchronized at
the center tap (TDL-AAAC) can work even in the non-minimum phase condition. In this paper, we propose a dual-mode space-temporal simultaneous processing
equalizer (Dual-mode ST-SPE) which has a simple configuration and also works in non-minimum phase condition. The Dual-mode
ST-SPE can reduce the computational complexity compared to the TDL-AAAC.
Yoshihiro Ichikawa received the B.E. degree in department of communication engineering, in National Defense Academy in 1995, and M.E. and D.E.
degree from Ibaraki University in 2001 and 2004, respectively. He joined the Japan Air Self Defense Force in 1995. His research
interests are an adaptive algorithm, an antenna design, and an adaptive array antenna.
Shigeki Obote received his B.E., M.E. and D.E. degrees in electrical and electronic engineering from Tottori University, Tottori, Japan,
in 1996, 1998 and 2000, respectively. Since 2000, he has been with department of media and telecommunications engineering,
faculty of engineering, Ibaraki University, Ibaraki, Japan, where he is currently a associate professor. His research interests
are in adaptive array antenna and wireless communications systems.
Kenichi Kagoshima received the B.E., M.E. and D.E. degrees in electronics engineering from the Tokyo Institute of Technology, Tokyo, Japan,
in 1969, 1971, and 1974, respectively. He joined the Nippon Telegraph and Telephone Corporation (NTT) Laboratory in 1974 and
researched and developed many kinds of radio communication antennas. Since 1997, he has been a professor at Ibaraki University,
Ibaraki, Japan. Dr. Kagoshima was a Secretary and Treasure, Vice Chairman, and Chairman of the IEEE AP-S Tokyo Chapter in
1992, 1993, and 1994, respectively. He was a chair of antennas and propagation professional group of IEICE in 1999 and 2000.
In 1973, he received the Yonezawa Prize for Young Engineers and 1998, best paper award from IEICE, respectively. 相似文献