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991.
High-temperature strength characteristics of rolled sheet, welded joints, and weld metal of niobium alloy 5VMTs of the system Nb-W-Mo-Zr at 1520–2020 K and stresses comprising 0.4–1.0 of the material ultimate strength are given. It is shown that welded joints and cast weld metal under high-temperature prolonged loading conditions are the same as the basic metal, and in a number of cases they surpass it in high-temperature strength characteristics. Empirical dependences are obtained connecting the short-term material strength with its creep resistance characteristics and stress-rupture strength at temperatures above the start of dynamic recrystallization.Translated from Problemy Prochnosti, No. 12, pp. 24–32, December, 1993. 相似文献
992.
本文研究了一种Zn-Ti合金新镀层,经盐水浸泡、中性盐雾和大气暴露试验结果试验,其耐蚀明显超过镀Zn层,并与镀Cd层相近,用缺口持久拉伸试验检验氢脆性,拉伸持续时间超过200h,达到原航空部部颁标准(HB5067-85),该镀层适用于高强度钢防护。 相似文献
993.
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997.
本文提出一种在τ-p 域内用特征积分法反演层状介质速度与密度的方法。该方法首先把有偏移距的地震资料变换到截取时间τ和水平慢度 P 域内,然后,对任取的二道平面波地震记录,分别用特征积分法反演波阻抗,再用这对波阻抗分离层状介质的速度和密度。文中讨论了误差对反演结果的影响,并对理论模型进行了试算,效果令人满意。 相似文献
998.
Database considerations in manufacturing systems integration 总被引:1,自引:0,他引:1
This paper deals with ideas that could form a basis for manufacturing integration. In recent times more attention is being paid to the idea of applying artificial intelligence (AI) techniques to manufacturing. However, very little attention is being paid to the proper use of these techniques. This research work explores three basic ideas:
1. 1. Applications of the entity-relationship approach to knowledge representation.
2. 2. The basic philosophy of expert database systems and
3. 3. Integration of manufacturing systems from the above two concepts.
The approaches for 1 and 2 are explained with actual implementation experiences, while a framework for integration is proposed from a more philosophical perspective. 相似文献
999.
Compared with the single sulphurating treatment, the duplex treatment of nitrocarburizing-sulphurating can more effectively
improve the properties of steel such as friction-reducing, wear resistance and anti-scuffing. Under the same processing parameters,
the sulphide layers were fabricated on the surface of CrMoCu alloy cast iron by single ion-sulphurating treatment and nitrocarburizing-sulphurating
duplex treatment, respectively. Through the analysis of the sulphide, the effect of the nitrocarburizing on the fabrication
of the sulphide layer was investigated. And the result shows that the fabrication of sulphide layer is promoted by the nitrocarburizing
treatment. 相似文献
1000.
The mixed oxidation of nickel in gases containing both oxygen and chlorine has been investigated using the techniques of thermogravimetric
analysis and examination of the corrosion products by scanning electron microscopy. Two regimes of corrosion behavior have
been detected: one in which a protective oxide film is present and the rate of corrosion is controlled by the transport of
the volatile products of the reaction between the gas phase and the oxide, and one in which the protective film is penetrated
and corrosion occurs rapidly enough to result in the ignition of the specimen. The oxide corrosion products on the specimens
after corrosion have characteristic morphologies, with the products of volatilization type corrosion consisting of large grains
and the products of ignition type attack consisting of fine spherical particles. Ignition is a serious hazard in environments
containing 0.25 pct or more Cl2 and 4 pct or more O2 by volume at temperatures between 1000 K and 1100 K, but is not produced by exposures at higher temperatures. A model based
on the stability of the protective film in steady state corrosion is presented which can be used to predict the transition
from volatilization to ignition type attack. 相似文献