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41.
Generation of 100 GHz trains of 500-700 fs pulses using dual-frequency beat conversion in a step-like dispersion profiled fibre is reported. The authors believe that this is the first time the generation and compression of soliton pulses using such a fibre has been demonstrated. The fabrication of such fibre assemblies does not require any special facilities and relies only on conventional optical fibre technology. They believe that the use of profiling the fibre dispersion by fibre segments instead of continuously dispersion-decreasing fibre is not only possible but preferable in many applications 相似文献
42.
Oxidation protection for carbon fibre composites 总被引:7,自引:0,他引:7
M. E. Westwood J. D. Webster R. J. Day F. H. Hayes R. Taylor 《Journal of Materials Science》1996,31(6):1389-1397
Carbon fibre-reinforced ceramic matrix composites are promising candidate materials for high-temperature structural applications such as gas turbine blades. In oxidizing environments at temperatures above 400°C, however, carbon fibres are rapidly oxidized. There is, therefore, a need to coat the composite in order to protect it against oxidation. This review identifies the requirements of an effective oxidation protection system for carbon fibre-reinforced ceramics and summarizes the work which has been carried out towards this goal over the last 50 years. The most promising coatings are those composed of several ceramic layers designed to protect against erosion, spallation and corrosion, in addition to possessing a self-healing capability by the formation of glassy phases on exposure to oxygen. 相似文献
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44.
This paper describes a fixed-weight Hamming binary neural classifier chip suitable for applications where high-speed operation is required. The circuit uses switched current-mode techniques throughout and achieves classification in one forward pass through the network. The chip was realized in 2.4-μm n-well CMOS technology and was designed to recognize the integers 0-9. It achieved a classification rate of 10 MHz without any observable tendency to misclassification or instability 相似文献
45.
ML McLaws C Murphy P Taylor M Ferson J Gold R Donnellan D Dalton 《Canadian Metallurgical Quarterly》1997,18(11):778-780
The rate of nosocomial respiratory syncytial virus (RSV) infection was measured in a large pediatric hospital using an incidence density method. The at-risk days for nosocomial RSV were summed during a defined winter period in which there were 54 admissions with community-acquired RSV infection giving a rate of 2.9 cases per 1,000 at-risk days (95% confidence interval, 0.3-5.4 per 1,000). 相似文献
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47.
Mechanisms for the abnormal copper (Cu) accumulation in the liver of LEC rats were examined using primary cultured liver parenchymal cells prepared from mutant LEC rats and those from control LEA rats (original strain). The Cu and metallothionein (MT) mRNA levels in the liver of LEC rats were caused to decrease to the same levels as those of LEA rats by removing Cu in vivo selectively with tetrathiomolybdate. Cu was taken up by LEC rat cells to the same extent as LEA rat cells by exposure to low medium Cu and to a higher extent by exposure to high medium Cu, while the MT mRNA level in LEC rat cells increased dose-dependently at a much higher rate than that in LEA rats. MT mRNA levels in both cells were comparable by exposure to cadmium, zinc and dexamethasone. The results indicate that expression of MT mRNA is selectively enhanced by Cu in LEC cells despite the fact that uptake of Cu is comparable with normal cells. 相似文献
48.
A new method is outlined which aims to predict high-cycle fatigue behavior of components which fail from stress-concentrators. This involves examination of the stress field in the vicinity of the stress-concentrator, and comparison with stress fields for cracks at known stress intensities. Methods which are currently used for simple notch geometries can thus be generalised, making the approach applicable to stress concentrators of any geometry. The method of prediction is shown to be stable, providing a solution of good accuracy when compared to analytical methods for standard specimen geometries. Favourable comparisons with experimental data have been achieved both for standard notches and for a corner geometry which represents a typical component case. 相似文献
49.
50.
Christensen Anne-Lise; Malmros Richard; Townes Brenda D. 《Canadian Metallurgical Quarterly》1987,1(2):45
After suffering a rupture of a left-sided aneurysm on the middle cerebral artery with prolonged arterial spasms, the prognosis for recovery of speech and motor functions of a 27-yr-old male patient was considered to be poor. Based on a Luria neuropsychological investigation that revealed many areas of preserved brain functions, rehabilitation efforts were directed toward training of specific abilities as well as compensatory skills using intact functions. This case demonstrates the interaction between the training program and the levels of motivation and persistence of the S and his family necessary to produce optimal rehabilitation outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献