Electrical and mechanical properties of BZT − xBCT lead-free piezoceramics

In this study, lead-free (1 − x)Ba(Zr_0.2Ti_0.8)O₃ − x(Ba_0.7Ca_0.3)TiO₃ compositions are synthesized via conventional solid oxide route, and the ceramics are fabricated with normal sintering in air. The effects of composition fluctuations on dielectric, piezoelectric, and mechanical properties are investigated. The phase structure and the microstructure are analyzed with X-ray diffraction and scanning electron microscopy. The best dielectric and piezoelectric properties of ε_r = 11 207 and d₃₃ = 330 pC/N were obtained for BZT−0.35BCT and BZT−0.5BCT ceramics, respectively. The mechanical behavior—in terms of Vickers hardness and compressive and flexural strengths—was investigated, and the best mechanical behavior was found in the vicinity of the phase transition boundary with x values between 0.5 and 0.6.     

The origin of the modulated structure in Sr2CuO3+δ (δ = 0.4): [CuO2] in-plane oxygen vacancy or apical oxygen vacancy?

We propose the question of the modulated structures of copper oxide is caused by the [CuO₂] in-plane oxygen vacancy or apical oxygen vacancy. Sr₂CuO_3+δ single-crystal samples were prepared using high-temperature and high-pressure methods. The major phase of Sr₂CuO_3+δ (δ = 0.4) single-crystal system is found to be constituted by the 5 a modulated structure with the Fmmm space group, which originates from the [CuO₂] in-plane oxygen vacancy appearing in octahedral Cu-O. Besides, the presence of the [CuO₂] in-plane oxygen vacancy may obliterate the superconductivity of the system. Experimental results deduce that the oxygen vacancy may appear in the apical oxygen sites in high-temperature copper oxide superconductors.     

动态评价技术在塔河碳酸盐岩缝洞型油气藏中的应用

塔河油田奥陶系油气藏是大型碳酸盐岩溶洞型油气藏，其储渗空间主要为大小不同的溶洞、裂缝带、溶蚀孔隙等组成，该油气藏具有极强的非均质性，单纯用静态资料来认识这类油气藏是非常困难。文章提出利用生产动态资料和信息进行该类型油气藏研究的新思路，利用人工神经网络技术在处理非线性相关参数预测方面的优势，并以渗流理论为基础，结合试井成果，选用已知油井的产量、油嘴、油压、含水率、气油比、原油密度等6个开发动态参数作为样品输入数据，推导出影响油气藏开发的重要参数（地层系数）与生产信息的关系，建立了人工神经网络预测储层参数的结构模型。通过塔里木盆地塔河油气田实例研究，说明了利用动态信息评价油气藏技术在碳酸盐岩缝洞型油气藏储层预测和非均质性分析等方面具有较高的实用价值。     

干燥过程中的高温快速工艺

介绍了干燥行业中的高温快速工艺,并利用传热传质原理分析了高温快速工艺干燥速度大、热效率高、物料品质好的原因.     

疏水缔合水溶性聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基十二胺)水溶液的粘度行为

采用前加碱二元胶束共聚-共水解法合成了三元疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基十二胺)[P(AM/NaAA/DiAC_(12))],研究了其水溶液的粘度行为。当x(DiAC_(12))=0．10%～0．40%时,在30℃、1 mol/L NaCl溶液中,其特性粘数[η]、Huggins常数K_H、粘均相对分子质量(?)分别为16．38～19．45 dL/g,0．214～0．394和8．36×10~6～10．36×10~6g/mol;K_H小于0．8,表明其分子内缔合作用较弱。P (AM/NaAA/DiAC_(12))在矿化度为19 334μg/g,盐水溶液中的表观粘度随疏水单体用量的增加而增加,随温度、剪切速率的增加而降低。在NaCl、CaCl_2的离子强度分别为1．26×10~(-3)～4．88×10~(-3)和1．07×10~(-4)～5．28×10~(-4)mol/kg的水溶液中,P(AM/NaAA/DiAC_(12))水溶液出现盐增粘现象,疏水单体用量越高,盐增粘效应越显著。     

含水汽凝析气体系相态仿真模拟研究

凝析气藏中的水汽对凝析气体系相态变化有影响。在地层中等温降压时，含水汽的烃类体系会发生反凝析现象。在反凝析现象中会产生凝析水和凝析油。这些反凝析液的聚集效应会造成凝析气井的产能严重损失。这就使得控制反凝析液的析出成为提高凝折气藏采收率的关键。在研究中，总结了含水汽凝析气体系的相态特征。同时，在对某含水汽凝析气体系相态实验分析的基础上，对该体系分考虑水汽和不考虑水汽2种情况进行相态仿真模拟。模拟结果大致与实验观测值一致。     

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)     

miPP/ziPP共混体系的流动性能

首次对茂金属聚丙烯(miPP)／齐格勒-纳塔聚丙烯(ziPP)共混体系的流动性进行了系统的研究。研究发现，在miPP／ziPP共混体系中，miPP含量的变化改变了共混体系的相结构，这种相结构会随着温度和剪切速率的变化而产生明显的变化，从而改变了体系的流动性能，且该共混体系在不同剪切速率下的流动曲线可以分别通过两个模型进行模拟。     

T-ZnO晶须增强环氧树脂复合材料的力学行为

研究了以四脚状氧化锌（T-ZnO）晶须为增强剂，环氧树脂复合材料的力学行为。结果表明，由具有三维空间结构的T-ZnO晶须为增强剂所制备的环氧树脂复合材料具有各向同性的力学性能，T-ZnO晶须填加质量分数为6%时，就可使材料的力学性能改善；拉伸强度提高到169%，拉伸功几乎提高了100%，冲击强度提高到300%，抗弯的断裂功提高到158%，而压缩强度略有下降。