Onset of multiple site damage and widespread fatigue damage in aging airplanes

This paper presents a methodology for predicting the thresholds of multiple site damage and widespread fatigue damage in fuselage lap slices. Widespread fatigue damage is a type of multiple cracking that reduces the airframe residual strength to a level below the damage tolerant requirement. The MSD threshold refers to the point in the lifetime of an airplane when two adjacent collinear fatigue cracks can linkup at the allowable stress. The WFD threshold is the point in time when linkup of a primary crack created from accidental damage and secondary cracks created from fatigue can result in a catastrophic failure. The methodology presented in this paper combines results from residual strength analysis and fatigue crack growth testing to determine these thresholds. In particular, a displacement compatibility approach is adopted to calculate residual strength in curved stiffened panels tested in the laboratory. The laboratory experiments also include fatigue testing of full-scale panels containing a debonded lap slice. Based on this methodology, the threshold of widespread fatigue damage for these laboratory panels, adjusted to zero minimum-stress cycling, is between 32,000 and 40,000 cycles, and the threshold of multiple site damage is about 70,000 cycles. This revised version was published online in August 2006 with corrections to the Cover Date.     

Probing exotic magnetic phases in ferrites with neutrons

The decades of the sixties and early seventies saw the neutron diffraction technique playing a major role in the elucidation of magnetic structures in a variety of ferrites in our laboratory. In 1979, Villain in his seminal paper on insulating spin glasses argued that the spinel structure affords topological frustration which can give rise to a variety of perturbed magnetic ordering, depending upon magnetic dilution in the ferrite. The neutron is a unique probe to explore the nature of spatial correlations of magnetic moments in such systems. This paper describes the exciting work carried out at Trombay recently in mixed ferrites which have led to the discovery of exotic magnetic phases like the uniaxial random ferrimagnetic phase and the canted random ferrimagnetic phase involving the coexistence of long-range magnetic order and disorder.     

电解液－Si_3N_4绝缘体界面表面基／复合中心模型的研究

本文在表面基模型基础上，借用半导体物理中复合／产生概念，提出表面基／复合中心模型，并研究了含两种类型表面基的Ｓｉ３Ｎ４绝缘体及其两种表面基（硅醇基和胺基）的比率对Ｓｉ３Ｎ４栅ｐＨ－ＩＳＦＥＴ敏感性能和稳定性的影响，其结果与实验结果相符。对改善ｐＨ－ＩＳＦＥＴ传感器的敏感特性具有实际指导意义。     

冷轧带肋钢筋在现浇楼盖中的应用

介绍了冷轧带肋钢筋的概念及分类 ,指出其在应用现浇楼盖中具有塑性好 ,粘结锚固可靠 ,强度高的优点 ,可取得较好的经济效益和社会效益     

茂名油页岩厂址比选分析

通过对茂名油页岩矿电联营项目电厂厂址选择的实践，对油页岩矿这种新型能源发电电厂选址工作的一般性和特殊性进行了阐述，并分析比较各方面的技术经济条伴，总结出油页岩矿电厂厂址选择的思路和方法，希望对厂址选择方面提供有益的启示。     

碛口水利枢纽坝址泥化夹层结构研究

从宏观到微观对黄河碛口水利枢纽坝址区红色沉积岩地层中泥化夹层的结构特性进行研究。宏观结构上，泥化夹层可分为节理带，劈理带和泥化错动带。泥化错动带为泥化夹层性状最差的部位，其微观结构模型为基质状微结构和紊流状微结构。     

利用电容传感器对啤酒液位进行检测

系统地阐述了电容传器在不同构造时的原理及特性，并通过理论和实验分析证明了用同轴电极电容液位计测量啤酒液位的可靠性，为灌装机酒阀静态实验台液位参数的研究提供了理论依据。     

阿尔及利亚供水工程自动化控制系统设计

介绍了阿尔及利亚某地供水工程的特征及要求 ,论述了供水工程自动化控制系统的构成、特点和设计思路。     

金沙江溪洛渡水电站坝址选择

溪洛渡水电站是以发电为主，兼有拦沙、防洪、漂木、航运等综合利用效益的巨型水电站；担负着西电东送，实现国家能源战略平衡，充分发挥三峡工程效益等具有重要意义的水电工程。几年来，经过大量的地质勘探和设计工作，通过对坝段、坝址的地形地质条件的比较，并结合水工枢纽布置的研究，选定河道顺直，谷坡陡峻，基岩裸露的玄武岩坝段及其中坝址作为溪洛渡水电站坝址。     

环境与洗涤因素对聚苯胺导电织物导电性能的影响

采用现场吸附聚合法制备聚苯胺/锦纶导电织物.研究外部环境条件与复合导电织物导电性能的变化关系和复合导电织物在温度、湿度、酸碱度及洗涤次数等不同环境条件下的导电性能.结果表明,随着湿度的降低,温度的上升,复合导电织物电导率下降;复合导电织物在pH〉5值溶液处理与洗涤后,织物的点对点电阻上升,导电性能下降.