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71.
Mold-slag friction and fracture may cause heat-transfer variations in continuous casting, which leads to steel shell temperature
and stress variations, resulting in surface cracks. Analytical transient models of liquid slag flow and solid slag stress
have been coupled with a finite-difference model of heat transfer in the mold, gap, and steel shell to predict transient shear
stress, friction, slip, and fracture of the slag layers. The models are validated by comparing with numerical models and plant
measurements of mold friction. Using reported slag-fracture strength and time-temperature-transformation (TTT) diagrams, the
models are applied to study the effect of casting speed and mold-powder viscosity properties on slag-layer behavior between
the oscillating mold wall and the solidifying steel shell. The study finds that liquid-slag lubrication would produce negligible
stresses. A lower mold-slag consumption rate leads to high solid friction and results in solid-slag-layer fracture and movement
below a critical value. Crystalline slag tends to fracture near the meniscus and glassy slag tends to fracture near the mold
exit. A medium casting speed may be the safest to avoid slag fracture, due to its having the lowest critical lubrication consumption
rate. The high measured friction force in operating casters could be due to three sources: an intermittent moving solid slag
layer, excessive mold taper, or mold misalignment.
Other symbols are defined in Table I 相似文献
72.
Brian Dipert 《电子设计技术》2006,13(6):56-58,60,62,64,66-67
蓝色激光(Blu-ray,简称蓝光,以下同)光盘和HD DVD均开始进入量产,但格式大战的赢家还不明朗。红色激光:简称红光,以下同)格式仍是某些应用的可靠替代方案,但用户版权限制和显示器与视觉的限制使格式的未来令人疑惑。 相似文献
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Veena Misra Xiaoli Xu Brian E. Hornung Richard T. Kuehn Donald S. Miles John R. Hauser Jimmie J. Wortman 《Journal of Electronic Materials》1996,25(3):527-535
In the present study, we have performed electrical characterization of oxides deposited via rapid thermal chemical vapor deposition using SiH4 and N2O. We have investigated the effect of temperature, pressure, and SiH4 to N2O ratio on the electrical and material properties of as-deposited films. We have found that as-deposited oxides deposited at low temperatures, low pressures, and with a low silane to nitrous oxide ratio of ~0.5% give good material and electrical properties. The as-deposited films are stoichiometric in nature and have high deposition rates. As-deposited films had very low Dit values, high breakdown fields, and excellent subthreshold swing. The leakage currents and metal oxide semiconductor field effect transistor current drive, although lower than thermal oxides, were found to be quite acceptable. We have also investigated the thickness dependence of the films and found that as the film thickness is reduced below 50Å, the reliability improves for all oxides including the silicon-rich deposited oxides. 相似文献
76.
Esterling Brian A.; Antoni Michael H.; Kumar Mahendra; Schneiderman Neil 《Canadian Metallurgical Quarterly》1993,12(2):132
Investigated the relationship of individual differences in repressive coping styles with differences in antibody titer to Epstein-Barr (EB) viral capsid antigen in a normal, healthy college population made up of people previously exposed to EB. Each of 54 1st-yr undergraduates completed a battery of physical-status questions and items pertaining to potential behavioral immunomodulatory confounds, along with the Taylor Manifest Anxiety Scale and the Marlowe-Crowne Social Desirability Scale. Ss reporting high and middle levels of anxiety had higher antibody titers to EB, suggesting poorer immune control over the latent virus, as compared with the low-anxious group. Similarly, high-defensive Ss had higher antibody titers than their low-defensive counterparts, and neither group differed from the middle group. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
77.
Reduction of optical proximity effects (OPE), at deep uv wavelength of 248nm, caused by the variation of stepper lens operating conditions is investigated. It is shown that many of these effects, which increase as the Rayleigh limit is approached, can be minimised, and in many cases eliminated, by suitable choice of lens numerical aperture (NA) and partial coherence (sigma, σ).
Application of these results should enable the user of advanced wafer steppers to carry out high resolution lithography with a minimum of time consuming optical proximity correction (OPC). 相似文献
78.
1引言2006年12月11日是我国正式加入世界贸易组织五周年,也是开放基础电信业务二周年。外资运营商进入中国市场的步伐也有加快的迹象。澳大利亚电讯(亚洲)总裁、澳大利亚电讯(中国)CEO贝裕铭日前表示,澳大利亚电讯要看3G(第三代移动通信)牌照发给哪家运营商,谁来做相关的3G业务,再决定战略性的合作。西班牙运营商Telefonica、新加坡电信、英国沃达丰相关负责人也表达了同样的态度。 相似文献
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80.
We consider the potential impact of Computer Supported Cooperative Work, with special reference to large technically advanced projects involving several organizations. It is vital that such projects are managed efficiently, without delays, since a product that reaches the market a few months earlier than its competitors enjoys a great advantage. Traditional methods of coordinating large projects, based on hierarchical communication, tend to produce delays, since technicians at remote sites are obliged to solve coordination problems by passing them up the hierachy. It would be better if such problems were solved by improvising conferences among the technicians; Computer Supported Cooperative Work will provide the technical means of implementing this heterarchical style of management without losing control of the project. The use of computers as a social medium raises methodological and ethical issues which are discussed in the final section. 相似文献