Damage mechanism in weldment of 2.25Cr-1Mo steel under creep-fatigue loading

The purpose of this study is to clarify damage process of “Type IV cracking” in weldment of a 2.25Cr-1Mo steel and to propose a micro damage prediction method. From continuous observation under a creep-fatigue test, it was found that spherical shape voids initiated and grew on grain boundaries in fine grain region and these voids grow continuously by changing their shape to crack-like. Both spherical and crack-like void growth rate equations were derived from the proposed void growth model. It was indicated that measured void growth rate under the creep-fatigue loading was well predicted by the growth rate equations.     

用φ76 mm穿孔机组生产φ63mm毛管的设备改进

介绍了用Φ76mm穿孔机组生产Φ63mm毛管的设备概况及其改进。改进后，Φ76mm穿孔机组增加了产品范围为后面的冷技工序减少了拉拔道次，从而降低了Φ51mm以下冷拔管的生产成本。     

Implementing software metrics — the critical success factors

This paper reviews the current state of industry with regard to the introduction of software metrics. It discusses the benefits that organizations have derived from metrication, it looks at why organizations have sought to introduce metrics programmes, how they have gone about introducing those programmes and the problems that they have encountered during implementation. The review found that, on the whole, only the sanitized aspects of metrics experiences have actually been published. This seems to be especially the case with respect to practitioner resistance. Very few organizations admit to having encountered resistance during the introduction of a metrics programme. The paper also includes the results of a pilot study, conducted by the first author, which examines the attitudes that developers hold towards the introduction of software metrics. The key findings of this pilot study are that positive attitudes to metrics correlate highly with levels of education and to job satisfaction.     

两缸天然气发动机工作均匀性分析

对一台火花点火式两缸天然气发动机进行了缸内示功图、进气压力波、空燃比、缸盖及活塞温度场和排放等项目的测试。试验和分析表明，两缸进气道中存在着明显的压力波动，波动程度取决于发动机工况。两缸混合气的质和量都不均匀，一缸空燃比偏浓，燃烧不完全，后燃倾向大；二缸空燃比较合适，燃烧过程较完善。两缸的尾气排放量相差不大。据此，可应用稀燃、快燃技术，以提高燃烧速度，改善燃烧过程；同时调整进气系统特性，将两缸混合气的质和量的不均匀性降到最低限度。     

提高大直径井眼机械钻速的几项措施

随着我国西部地区石油勘探开发的进展，5000－7000m的深探井所钻数量不断增多，套管程序增加，特别是大尺寸井眼所钻深度明显加大。由于国产大尺寸钻头结构单一、型号少，破岩机械能量和水力能量不足，在易斜井段目前尚无可靠的防斜保直措施，以及钻井液性能不适宜等原因，大尺寸井眼的钻这远远低于215．9mm井眼的钻速。据此，提出了几项可以提高大尺寸井眼钻速的措施：增加大尺寸钻头的种类，采用阶梯式扩眼钻头，强化钻井参数和水力参数，选用中速动力钻具，改善钻井液性能以及采用冲击旋转钻具等。     

Genetically modified starter and protective cultures

Modern approaches towards starter and protective culture improvement rely on advances in molecular biology. For most microorganisms used for food production, gene technological methods have been well developed. By recombinant DNA technology, ‘tailor-made’ starter and protective cultures may be constructed so as to combine technically desirable features. A single strain which normally would fail to accomplish a given ‘wtask’ may now be improved so as to meet a set of requirements necessary for a specific production or preservation process (e.g. wholesomeness, no off-flavour production, overproduction of bacteriocins or particular enzymes). In addition, undesirable properties (e.g. mycotoxin or antibiotic production by cheese moulds) may be eliminated by techniques such as ‘gene disruption’.     

电子称在化工生产中的应用

针对化工生产环境的特点对电子称重仪器在化工计量中的正确选择和使用作一些分析阐述。     

Some results on generalized residual entropy

Shannon’s entropy plays an important role in the context of information theory. Since this entropy is not applicable to a system which has survived for some units of time, the concept of residual entropy has been developed in the literature. Here we generalize the residual entropy by choosing a convex function ? with ?(1) = 0. In this paper, some orderings and aging properties have been defined in terms of the generalized residual entropy function and their properties have been studied. Quite a few results available in the literature have been generalized and some distributions (viz. uniform, exponential, Pareto, power series, finite range) have been characterized through the generalized residual entropy.     

降低氧化铝生产中熟料折合比的探讨

在氧化铝生产过程中，熟料折合比是烧结法一项重要的综合性指标，本文通过对熟料折合比的定义、计算公式的剖析，分析了生产过程中影响熟料折合比的主要因素，对有效降低熟料折合比的措施进行了探讨。     

铝电解生产节能初探

本主要是从实行设备的经济运行、提高整流系统的利用率、以及改革落后工艺，改进操作这几个方面进行探讨，并进行了实施推广，从而取得了良好的经济效益。