Temperature cycling and its effect on mechanical behaviours of highporosity chalks

Temperature history can have a significant effect on the strength of water-saturated chalk.In this study,hydrostatic stress cycles are applied to understand the mechanical response of chalk samples exposed to temperature cycling between each stress cycle,compared to the samples tested at a constant temperature.The total accumulated strain during a stress cycle and the irreversible strain are reported.Chalk samples from Kansas(USA)and Mons(Belgium),with different degrees of induration(i.e.amount of contact cementation),were used.The samples were saturated with equilibrated water(polar)and nonpolar Isopar H oil to quantify water weakening.All samples tested during 10 stress cycles with varying temperature(i.e.temperature cycled in between each stress cycle)accumulated more strain than those tested at constant temperatures.All the stress cycles were performed at 30℃.The two chalk types behaved similarly when saturated with Isopar H oil,but differently when saturated with water.When saturated with water,the stronger Kansas chalk accumulated more total strain and more irreversible strain within each stress cycle than the weaker Mons chalk.     

Prominent consequences of role stress: A meta-analytic review.

Role stress has received a lot of research attention in psychological, sociological, and organizational studies over the last several decades. Based on a literature review of about 300 journal articles, this article examines prominent consequences of role stress. Specific focus is on researching differences in relationships between facets of role stress (i.e., role ambiguity, role conflict, and role overload) and frequently cited consequences using techniques of meta-analysis. Findings indicate that each role stress facet has a different relationship with the eight consequences studied. Role stress research can benefit from looking at each facet individually in addition to role stress generally. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

掺镱双包层高功率光纤激光器输出特性研究

对线形腔掺镱双包层高功率光纤激光器的输出特性进行了研究 ,通过求解速率方程 ,得到了激光器泵浦阈值功率、输出光功率和斜率效率的表达式。分析了光纤长度、腔镜反射率和泵浦波长等因素对激光器阈值功率、输出光功率和斜率效率的影响 ,为高功率光纤激光器的优化设计提供了理论依据     

城域网中光纤光缆的探讨

城域网的建设是今后光纤网络建设的一个热点，根据城域网的特点和系统技术要求选择光纤光缆是网络设计的重要组成部分。本根据城域网的特点和需求，对市场上现有的光纤光缆做了详细的分析和探讨，提出了城域网规划中光纤光缆选择的原则和具体的建议。     

On the linear correlation between microhardness and mechanical properties in polar polymers and blends

The tensile elastic modulus (E), yield stress (σ_Y) and microhardness (MH) of neat and binary and ternary blends of glassy semicrystalline ethylene–vinyl alcohol copolymer (EVOH), a glassy amorphous polyamide and a semicrystalline nylon‐containing ionomer covering a broad range of properties were examined. The tests were carried out on dry and water‐equilibrated samples to produce stiffer and softer materials, respectively. From the results, more accurate linear correlations were found to describe adequately the microhardness, modulus and yield stress of these strongly self‐associated polymers through hydrogen bonding. Copyright © 2003 Society of Chemical Industry     

储层应力敏感性影响因素研究

全面分析储层应力敏感性产生的机理认为，外部因素的改变会引起储层产生应力敏感性．而储层岩石物性等内部因素对应力敏感性的强弱起决定性作用。室内岩心应力敏感性评价时．仪器与设备的精度、加载与卸载方式、实验用流体类型以及各种人为因素等都会对评价结果产生影响，其中岩心密封套在高压、高温条件下的密闭性会对实验结果产生较大影响。所以储层应力敏感性不应该从孔隙度和渗透率的高低进行简单评价，中、高渗储层和低渗储层在生产过程也都可能表现出较强的应力敏感性现象。     

Fast Positive Feedback Between the Adrenocortical Stress Response and a Brain Mechanism Involved in Aggressive Behavior.

Aggressive behavior induces an adrenocortical stress response, and sudden stressors often precipitate violent behavior. Experiments in rats revealed a fast, mutual, positive feedback between the adrenocortical stress response and a brain mechanism controlling aggression. Stimulation of the aggressive area in the hypothalamus rapidly activated the adrenocortical response, even in the absence of an opponent and fighting. Hypothalamic aggression, in turn, was rapidly facilitated by a corticosterone injection in rats in which the natural adrenocortical stress response was prevented by adrenalectomy. The rapidity of both effects points to a fast, mutual, positive feedback of the controlling mechanisms within the time frame of a single conflict. Such a mutual facilitation may contribute to the precipitation and escalation of violent behavior under stressful conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

两种基于弯曲损耗的光纤测试仪器原理及应用

光纤通信技术的飞速发展带动了光纤测试仪器的发展。主要对两种利用弯曲损耗对光纤进行检测的仪器——光纤识别仪、光纤对线器的原理、结构及其在光纤通信工程中的应用进行了阐述，两种仪器可以在不中断光纤通信的情况下对光纤进行检测，极大地降低了对光纤通信系统的影响，对光纤通信系统具有重要意义。     

小波变换分离太阳射电频谱图中的纤维结构

太阳射电爆发纤维精细结构是太阳射电爆发活动中一类重要的观测现象,利用二维小波变换对纤维精细结构动态频谱图进行处理,分离频谱图中的纤维结构。首先对原始频谱图实行多层小波变换,由低频分量重构原始图像,就可得到爆发的背景信息,令原始频谱图减去背景并经过阈值处理后,便可将原始频谱图中的纤维结构很好地分离出来。     

双转向垂向控缝技术实验研究及现场应用

针对压裂过程中缝高较难控制的问题，研制开发出新型的油溶性垂向双转向剂，并开展了室内实验研究。首次验证了转向剂对裂缝延伸的控制机理，确定了转向剂的适用浓度及控缝能力。实验表明，转向剂可以增加隔层应力3～4MPa左右。在此基础上研究了控制裂缝高度施工方案的设计方法，并利用全三维软件结合垂向应力剖面对控缝技术进行了优化。现场推广应用30井次，取得了较好的控缝效果。