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排序方式: 共有479条查询结果,搜索用时 15 毫秒
1.
Masami Ikeda Susumu Fukumoto Hiroshi Takao Shinya Ohtsuka Eiichi Haginomori Masayuki Hikita 《Electrical Engineering in Japan》2002,141(4):16-24
This paper describes the dielectric breakdown characteristics of oil and oil‐impregnated paper for very fast transient (VFT) voltages. Blumlein circuits generate VFT voltages of 60 and 300 ns in a pulse width that simulates disconnecting switching surges in gas‐insulated switch gears. We measured the breakdown voltages of needle‐to‐plane, plane‐to‐plane oil gaps and several pieces of paper between plane electrodes for VFT and lightning impulse voltages. The measured data were formulated in V‐t characteristics and Weibull probability distributions. The inclination n of V‐t characteristics of insulating paper is 150, which is less than n = 13.7 of the plane‐to‐plane oil gap in the VFT time range. The shape parameters of Weibull distribution obtained in this study show that the scattering of breakdown voltages of paper is much less than that of oil. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 16–24, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10043 相似文献
2.
Resistance microwelding of fine crossed nickel wires is of increasing industrial importance for electrical connections in
downsized electronic and medical devices, but the understanding of the process is very limited. A study has, therefore, been
performed to clarify the basic joining mechanisms, in which the effects of main process parameters (welding current and force
and weld time) were investigated by detailed mechanical testing and metallurgical examinations. A bonding mechanism with main
process stages (wire cold collapse, surface melting, molten-phase squeeze-out and, solid-state bonding) was proposed. A new
technique has also been developed to optimize the process by initiating the welding current well before the electrode force
has reached its full nominal value. 相似文献
3.
The asymptotic correlations among maximum likelihood (ML) and various least squares (LS) estimators in factor analysis are derived. The LS estimators include the unweighted (ULS) and weighted estimators for unstandardized variables and the ULS estimators for standardized variables. The derived formulas cover the cases with restrictions on parameters. Numerical examples with simulations are provided to confirm the accuracy of the formulas and the influence of scales on the asymptotic correlations.
相似文献4.
R Fukuda XT Nguyen N Ishimura S Ishihara A Chowdhury N Kohge S Akagi M Watanabe S Fukumoto 《Canadian Metallurgical Quarterly》1995,172(5):1191-1197
Hepatitis B virus (HBV) carriers with antibody to hepatitis e antigen comprise asymptomatic carriers (ASCs), who have low replication levels of HBV, and patients with chronic active hepatitis (CAH), who have high levels of viral replication. To investigate whether defects in the X protein might be responsible for this difference in the level of viral replication, nucleotide sequences of X and precore gene regions in serum HBV were analyzed in 19 ASCs and 9 CAH patients. All patients had a point mutation creating a stop codon in the precore region. Seventeen ASCs (87.3%) had identical mutations consisting of 4 noncontiguous 1-bp deletions or an 8-bp deletion, both of which truncate the normal X protein, whereas no CAH patient had an X gene mutation (P < .001). Thus, deletion of the X protein might be responsible for the low levels of viral replication in ASCs. 相似文献
5.
I. Lum E. Biro Y. Zhou S. Fukumoto D. R. Boomer 《Metallurgical and Materials Transactions A》2004,35(1):217-226
Electrode pitting was investigated in resistance spot welding of 1.5-mm-thick sheet aluminum alloy 5182 using a medium-frequency
direct-current welder and electrodes with a tip face curvature radius of 50 mm and tip face diameter of 10 mm. Detailed investigation
of the metallurgical interactions between the copper electrode and aluminum alloy sheet was carried out using scanning electron
microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) and X-ray diffraction (XRD). The results indicated that electrode
degradation, which eventually leads to weld failure, proceeded in four basic steps: aluminum pickup, electrode alloying with
aluminum, electrode tip face pitting, and cavitation. Since pitting and cavitation result from Al pickup and alloying, periodic
electrode cleaning could extend electrode tip life by limiting the buildup of Al on the tip face. This work is part of the
effort to improve electrode tip life in resistance spot welding of aluminum alloys for automotive applications. 相似文献
6.
S Yoshida M Fukumoto N Yoshimura K Oobayashi Y Takada 《Canadian Metallurgical Quarterly》1996,10(3):329-333
Hypertension attributable to pheochromocytoma is a very attractive model for the elucidation of the pathogenesis of hypertension. Sixteen different point mutations in the RET proto-oncogene and 30 mutations in the Von Hippel-Lindau (VHL) tumor suppressor gene have been identified so far associated with expression of pheochromocytoma. Each of these mutations initiates either the syndrome of multiple endocrine neoplasia type 2 (MEN 2) (MEN 2A and MEN 2B) or the VHL disease. Certain mutations in both genes are associated with the presence of pheochromocytoma. In general, these pheochromocytomas produce catecholamines that result in hypertension. Therefore, analysis for germline mutations in these genes are of practical value, because susceptibility to these diseases can be predicted in as yet clinically unaffected relatives. 相似文献
7.
Masahiro Baba Goh Itoh Haruhiko Okumura 《Journal of the Society for Information Display》2007,15(3):205-211
Abstract— In this paper, a software‐processed edge‐ and level‐adaptive overdrive (SELAO) method, which is a novel overdrive technique that utilizes not only a temporal change of gray levels but also a spatial edge intensity of motion pictures, is proposed. The SELAO method is a software video‐processing technology to improve motion‐picture quality rendered on LCDs more than is possible with a conventional SLAO method without edge‐adaptive overdrive, and it works in real time on commonly used personal computers (PCs). 相似文献
8.
Kaneko M. Aratani K. Fukumoto A. Miyaoka S. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1994,82(4):544-553
IRISTER (IRIS Thermal Eclipse Reading) is a remarkable technique for achieving superresolution in optical disks. Two applications of IRISTER are Magnetically induced SuperResolution (MSR) and Premastered optical disk by SuperResolution (PSR). Magnetically induced SuperResolution (MSR) has been realized in magneto-optical disks using exchange-coupled magnetic multilayer films. Two new detection methods have been developed. In the front aperture detection (FAD) method, the heated area in the light spot works as an optical mask so that the signal is read out only from the remaining crescent-shaped area in the spot. In the rear aperture detection (RAD) method, the signal is read out only from the heated area. The cutoff spatial frequency for both types of detection is more than two times higher than that in conventional detection. A high C/N of 42 dB is obtained in the MSR disks by both methods for a mark length of 0.3 μm, which is much shorter than the optical limit. Premastered optical disk by SuperResolution (PSR) has been realized in read-only optical disks using phase-change materials. In the front aperture detection (FAD) method for PSR, the prerecorded signal is read out only from the high reflective crescent-shaped area in the light spot, because the reflectance of the heated area is too low. A C/N of 51 dB for a mark length of 0.3 μm has been obtained for the PSR disk 相似文献
9.
10.
Simultaneous removal of acetaldehyde, ammonia, and hydrogen sulphide from air by the impregnated active carbon was studied at 25C. p-Aminobenzoic acid (PABA), phosphoric acid (H3PO4), and metal compound such as copper (II) chloride dihydrate (CuCl2·2H2O), copper (II) nitrate trihydrate (Cu(NO3)2·3H2O), and potassium iodide (KI) were investigated as impregnation ingredients. Acetaldehyde and ammonia were simultaneously removed from air by the active carbon impregnated with PABA and H3PO4. The removal was found to be made mainly through chemical reaction. Acetaldehyde, ammonia, and hydrogen sulphide were simultaneously removed from air by the active carbon impregnated with PABA, H3PO4, and metal compound such as CuCl2·2H2O, Cu(NO3)2·3H2O, and KI. 相似文献