Microstructural changes accompanying repair welding in 5xxx aluminium alloys and their effect on the mechanical properties

At the shipyards, the aluminium alloy 5083 is welded with a multi-pass sequence using the metal inert gas technique. If, while checking the weld integrity either after welding or during service, defects are detected in the vicinity of the weldment, repairs are usually employed to extend the service life.

The repair method involves removal of the upper passes, depending on the thickness and re-welding under the same conditions.

Purpose of this paper is to examine the microstructural changes accompanying repair welding, define their effect on properties of primary importance and set, if possible, an upper limit as far as the number of repairs is concerned.     

涂料的发展和市场新动态（Ⅰ）

介绍了近年来国内外涂料生产和市场的一些情况,特别对国外企业在中国投资设厂的分布和产能做了重点论述,介绍了近年来国内外研发的一些新产品。     

Strain waves in colliding bars having nonparallel faces

The paper reports the experimental investigation data for the effect that nonparallel faces of bars under impact exert on the parameters of longitudinal and bending strain waves generated in the bars. The changes in stress magnitudes in the bar under impact with growing angle of the impact faces offset are described. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 73–78, November–December, 2006.     

Cyclic strength of parts with overlapping zones formed by roller burnishing

The authors study residual stresses in and cyclic strength of shaft with overlapping zones formed during roller burnishing. The most significant decrease in fatigue strength is shown to occur in the presence of an overlapping zone with the areas arising due to a lowered roller burnishing pressure in the second pass. __________ Translated from Problemy Prochnosti, No. 3, pp. 144–148, May–June, 2006.     

Sicherer und wirtschaftlicher Betrieb von Kraftwerken – Ergebnis der Forschung im Bereich Werkstoffe,Auslegung und Instandhaltung

Safe and Economic Operation of Power Plants – Research Results in the Field of Materials, Design and Maintenance Components of power plants which undergo high temperatures are subjected to complex loading situations. The requirements on the used materials result from the special operation conditions of the plants and have to be adjusted to the steadily growing requirements on higher efficiency of the complete power plant as well as to those of safe and economic operation. The expenses for control and downtimes are directly connected with economic efficiency and availability. However, in case of new procedures or components it is not possible to revert to the existing know‐how. Different failure mechanisms than known before can occur. The same goes for the load situation. Therefore the knowledge base has to be extended to in‐advance or even parallely running scientific examinations that life assessment and maintenance strategies can be applied which guarantee the operational reliability and the efficiency of the plant. The main emphasis of these F&E works has to be put on condition monitoring based on actual operational data, the standard materials’ and component’s behaviour (deformation, damage and failure behaviour) in connection with design of components and the related material laws. In the framework of applied AVIF projects, following problems are handled:. – qualification of materials by determinating parameters related to practise. – optimal design of components by making available material laws and numerical tools. – economic manufacturing of components by qualifying processing methods such as welding. – The results can be transferred to concepts for safe and economic operation of power plants, especially for newly introduced materials for which there is no operational experience available.     

BP神经网络在致密砂岩储层识别中的应用

川西须家河组地层岩性复杂,属于超致密低孔渗储层,所以储层识别是该地层天然气勘探中所面临的关键问题和难点之一。针对常规储层识别准确率不高的状况,提出利用BP神经网络进行储层的气水干层识别,利用模糊聚类和产层测试结果标定建模样本,采取随机抽样形成建模集与测试集,建立BP神经网络模型对23口井的储层进行气水干层预测,正确率达77.9%以上,明显提高了该地区的测井解释精度,并提供了一种准确率较高的储层预测方法。     

Provision of accuracy for quantitative determination of small amounts of components: Principles of resolving the problem and their realization

Versions are suggested for resolving the problem of monitoring the accuracy of determining small amounts of components in samples of substances and materials. __________ Translated from Izmeritel'naya Tekhnika, No. 1, pp. 52–57, January, 2006.     

龙滩尾水出口枯期围堰设计与施工

介绍龙滩水电站尾水出口工程枯期围堰的设计参数及计算过程,结合施工过程中的实际情况,总结得出土石子围堰的闭气方法和浆砌石主围堰堰体防渗的应注意几个问题。     

调节阀的闪蒸和气蚀

针对调节阀的闪蒸和气蚀问题，介绍了调节阀在选型和使用中的要点。