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21.
Highly reliable telecommunication networks require new technologies, such as the reliability specification, design, and evaluation method used at NTT. This paper describes the basic concepts of this method, and the ARDES-NET (Availability Reliability Design and Evaluation System for NETworks) software tool is used to support the reliability design and evaluation. ARDESNET has a user-friendly interface and can be easily put into practice 相似文献
22.
Makoto Hino Minoru Hiramatsu Koichi Akiyama Hitoshi Kawasaki Masato Tsujikawa Makoto Kawamoto 《Materials and Manufacturing Processes》1997,12(1):37-46
A high powered YAG laser with kaleidoscope for surface modification was applied to the surface hardening of carbon steels containing 0. 18-0.54 wt% C without the absorbents, and the relationships between laser processing and surface hardening were investigated by hardness and microstructure. The structure of the hardened zone underwent complete martensitic transformation in all of the carbon steels tested, and its hardness increased with greater carbon content. Under identical irradiated conditions, the hardened zone expanded with increasing carbon content. A hardened zone extending from the surface to a depth of 1.0 mm was obtained at a laser power of 1.0 kW and a scanning speed of 1 mm/sec. It was found that in the surface hardening of carbon steels, a high powered YAG laser can be used to control the hardened zone by selecting the appropriate irradiation conditions, however, the hardened zone was affected by the assistant gas and the flow rate. 相似文献
23.
S Hayashi T Sugiyama A Yachi K Yokota Y Hirai K Oguma N Fujii 《Canadian Metallurgical Quarterly》1997,32(5):593-597
STUDY OBJECTIVES: To determine the rates of alcohol-related morbidity and mortality in a cohort of intoxicated ED patients 5 years after presentation and to compare them with those of non-intoxicated ED patients. METHODS: The study group comprised 150 consecutive ED patients who presented with intoxication (blood alcohol level higher than 100 mg/dL) in June 1986 and 50 control patients matched for age, sex, ED arrival time, and date. The setting was an urban university hospital ED. Morbidity and mortality over a 5-year follow-up period were measured using hospital ED and admission records from all state Level I trauma centers and computerized statewide databases. RESULTS: The 5-year mortality rate among alcohol-intoxicated patients was 2.4 times that of the comparison group (95% confidence interval, .3 to 18.9). The 5-year death rate among intoxicated patients aged 40 to 69 years was especially high (19%). Thirty-seven percent of the intoxicated patients made at least one alcohol-related ED revisit during the follow-up period, compared with 6% of the comparison group (P < .001). Intoxicated patients were more likely to revisit EDs because of suicidal behavior or domestic violence (P = .001). Admission to an alcohol detoxification unit during the follow-up period occurred in 24% of the intoxicated patients, compared with 10% of the sober controls (P = .03). At least one arrest for drunk driving occurred in 47% of the intoxicated group; the rate was lower, but still substantial, in the comparison group (20%, P < .001). CONCLUSION: A single alcohol-related ED visit is an important predictor of continued problem drinking, alcohol-impaired driving and, possibly, premature death. 相似文献
24.
25.
Makoto Kohga 《含能材料》2006,14(6):471-474
1 IntroductionThe ammonium perchlorate ( AP)-based compositepropellant is currently the most widely used one becausethis propellant has good burning characteristics and me-chanical properties. One of the few serious drawbacks ofthe AP-based propellant is that its products of combus-tion, which include HCl, chlorine, and chlorine oxides,cause atmospheric pollution. Increasing concern for aclean atmosphere in recent years has resulted in a com-pelling need for developing a chlorine-free,enviro… 相似文献
26.
Takashi Ishikawa Sunao Sugimoto Masamichi Matsushima Yoichi Hayashi 《Composites Science and Technology》1995,55(4):349-363
Compression-after-impact (CAI) tests have been conducted for quasi-isotropic thick plates with 48 plies by using the NASA method and on plates with 32 plies by using the SACMA method. Specimens are made of CF/PEEK (APC-2) and conventional CF/epoxy for the NASA plates and CF/epoxy for the SACMA plates. In the NASA CAI tests, the sequence of delamination buckling and its propagation is clearly revealed through various experimental techniques. One major technique is moiré topography, and the other is thermo-mechanical stress analysis with a high-accuracy infrared sensor. The arrest of delamination propagation just before catastrophic failure due to high fracture toughness is clearly captured by the moiré camera. This behavior provides good CAI values of CF/PEEK. The initial buckling properties of the delaminated region by the impact are then extensively discussed. Numerical predictions of initial buckling stress have been obtained by modelled geometry of the delaminated region simplified from its precise structure clarified by ultrasonic C-scanning. They agree fairly well with the experimental results. The in-plane stress distribution in the delaminated region before initial buckling is measured by an infrared stress graphic system. This compared favorably with finite element predictions. Two types of symmetric buckling modes with respect to the central plate surface, twin and single peak ones, are experimentally captured. 相似文献
27.
Three photoconductive diamond detectors with highly oriented diamond (HOD) films fabricated by the same process were characterized with respect to temporal response, spectral responsivity and its spatial uniformity over the wavelength range from 190 to 250 nm. Temporal measurements showed a drift in the baseline, suggesting the presence of deep level carrier traps. The responsivity of specimen No. 2 was more than twice those of the other two specimens, but it showed an unpredictable current fluctuation. It was found that the spatial uniformities of all the specimens were too low for radiometric purposes. A prominent peak, thought to be due to photoemission, was found in the responsivity spatial distribution of specimen No. 3 under a negative applied voltage. 相似文献
28.
In this paper, we describe two kinds of characteristic nonlinear dynamics in two-component Bose–Einstein condensates. For two overlapping components, we analyzed the collective modes and a variety of nonlinear mode couplings, which were then confirmed by numerical simulation of the time-dependent Gross–Pitaevskii equations. Next, we consider the nonlinear dynamics of two condensates after abruptly turning on the intercomponent coupling strength. For strong intercomponent interactions the out-of-phase density wave of the condensates became unstable, leading to mugtiple domain formation. 相似文献
29.
Spreading depression (SD) is known to be involved in the N-methyl-D-aspartate receptor-mediated neuronal damage. In urethane-anesthetized rats, we examined the release of adenosine and glutamate during SD induced by microdialysis of high K+ perfusate through the hippocampal CA1 area. The effects of endogenous adenosine upon SD were studied by applying an adenosine antagonist, theophylline (1 mM) and by a simultaneous application of adenosine uptake blockers, dipyridamole (DPR) (100 microM) and nitrobenzylthioinosine (NBI) (50 microM). The dialysates were sampled every 5 or 10 min and analyzed by HPLC. SD was identified by flattening of background EEg and disappearance of population spikes recorded from the pyramidal cell layer of CA1 area by a glass microelectrode. Adenosine and glutamate release was enhanced significantly in association with the occurrence of SD. Theophylline increased the release of glutamate and the incidence of SD and decreased the latency of the SD occurrence. DPR+NBI decreased the release of glutamate and the occurrence of SD, but increased extracellular adenosine concentration. The effects of DPR+NBI were blocked by application of a selective antagonist of adenosine A1 receptor, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 0.1 microM). These findings suggest that endogenous adenosine exerts inhibitory influences upon the development of SD and the glutamate release through the A1 receptor in rat hippocampus. 相似文献
30.
Physical optics (PO) is an approximation method for high‐frequency scattering and diffraction problems. But PO fields are inaccurate in the shadow region where the source is screened by the scatter. Two key factors of the error for PO are (i) edge diffraction coefficients and (ii) existence of fictitious penetrating rays. The correction with respect to the former has been extensively investigated by many authors using various ray techniques such as GTD, UTD, and UAT. On the other hand, the latter was identified recently by the authors. This paper proposes novel PO‐based calculation procedures termed PO‐AF and PTD‐AF, where PO and Aperture Field Integration Method (AFIM) are merged with the help of special elementary diffraction coefficients. These can uniformly cover the whole angular region and only the error factor (ii) is removed in PO‐AF while both (i) and (ii) are removed in PTD‐AF. The theoretical backgrounds of PO currents are discussed in terms of field equivalence theorem and visualization of EM waves. Next, new methods are proposed and their validity is numerically demonstrated for 2D scattering problems of a strip, a corner reflector, and a cylinder of circular arc. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 1–10, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20037 相似文献