Microstructure study of Sm,Mn-modified PbTiO3 piezoelectric ceramics by XRD profile-fitting technique

By using the X-ray diffraction profile-fitting technique, the microstructures of Sm, Mn-modified PbTiO₃ piezoelectric ceramic discs, including ferroelectric domain sizes, microstrains, and their variations with the poling strength have been quantitatively investigated. The results manifest that the modified PbTiO₃ ceramics contain a high density of domain walls due to the presence of finely-divided coherent domain structures (tens of nanometres in dimension). The poling treament can evidently influence the domain-size distribution, with a more homogeneous microstructure being developed; however, it simultaneously causes high anisotropic microstrains within the structure which, together with the high density of domain walls, is expected to be responsible for the unusual high electromechanical coupling properties possessed by this material.     

化工防腐蚀涂料应用情况介绍

介绍了氯磺化聚乙烯涂料、改性聚苯乙烯涂料、环氧树脂类涂料、水冷器涂料、抗静电涂料等涂料的性能、用途和在洞庭氮肥厂的使用情况.同时对几种涂料施工方案进行了比较.     

Analysis of simian hemorrhagic fever virus (SHFV) subgenomic RNAs, junction sequences, and 5' leader

Full-length simian hemorrhagic fever virus (SHFV) genome RNA (about 15 kb in length) and six subgenomic RNAs, ranging in size from 0.65 to 4.7 kb, were detected by Northern blot hybridization in MA104 cytoplasmic extracts with a 3' genomic antisense probe. The 5' regions of the two smallest subgenomic RNAs (RNAs 6 and 7) were cloned and sequenced. Sequence analysis indicated that these two RNAs contained a common 5' leader sequence joined to the subgenomic RNA bodies via a highly conserved junction sequence; the junction sequence of RNA 7 was 5'-TTAACC-3', while that of RNA 6 was 5'-TCAACC-3'. The complete 5' leader sequence (208 nt) was obtained from genomic RNA. The genomic 5' junction sequence is identical to that of RNA 7. Northern blot hybridization with an antisense 5' leader probe confirmed the presence of the complete leader sequence in all six species of subgenomic RNA. In its virion morphology, genome size, gene order, and replication strategy, SHFV is most similar to viruses such as equine arteritis virus, lactate dehydrogenase-elevating virus, and Lelystad virus/porcine respiratory and reproductive syndrome virus.     

加入WTO对我国水利科技工作的影响及对策

加入WTO后，对我国水利科技发展的影响主要表现在：研究开发活动、技术标准和知识产权保护方面，为适应WTO的各项规则，履行我国政府所作出的承诺，必须调整水利科技政策和发展战略，促进我国水利科技事业的健康发展。     

一种系统信息提示的方法及其在汇编程序设计中的实现

本文介绍了系统信息提示的一种方法，井重点讨论了用８０８８汇编语言实现的方法。它采用基本信息串表和索引表，对于使用频度较高的系统，可以大大节约系统内存，具存较好的实性用。     

炼油厂区内新建项目改扩建施工现场灭火器配置的分析

在对石油化工改扩建工程施工现场火灾危险因素识别评估的基础上，判定现场火灾危险等级、火灾类别，对灭火级别和保护距离进行验算，提出施工现场灭火器选型和配置方案。     

A force modulation study on crystallization process in ferroelectric vinylidene fluoride and trifluoroethylene copolymer films

This paper introduces the Force Modulation technique to the study of crystallization process in ferroelectric vinylidene fluoride and trifluoroethylene copolymer films. Using this technique we have successfully visualized ferroelectric crystalline domains and observed that these ferroelectric domains grow out from amorphous phase, unite into strip-like structures, and finally congregate into a union. Force Modulation can weaken the influence of topography on imaging of ferroelectric domains, and reveal more details, which are difficult to be observed in topographical image.     

输气管道投产置换过程气体混合规律研究

目前国内输气管道置换工艺主要依据人工经验进行，存在较大的盲目性，导致天然气管道投产成本较高，安全风险较大，有必要对输气管线安全投产工艺进行科学、系统的研究，实现输气管道的安全、高效、经济投产模式。文章讨论了现有置换工艺中不同的置换方式，认为不加隔离器的置换方法具有置换效率高、费用低以及安全可靠等优点，是一种有前途的新工艺、新方法。同时，为确保置换过程的安全性，针对置换过程中注氮量确定的盲目性问题，采用模拟试验方法，研究了天然气与氮气、氮气与空气混合段在不同流速和背压下长度的变化规律，从而为确定合理的用氮量提供了理论依据。     

气藏水平井非稳态产能预测新方法研究

针对高产气藏储层特征,建立起气藏水平井非稳态产能预测模型,对高产气藏的产能进行分析和预测.实例分析表明,通过该模型形成的基于气藏与井筒耦合作用的非稳态产能预测新方法,对于单井产能预测具有优越性、长远性和实用性.该方法可直接利用不稳定压力测试成果进行预测,还可通过生产动态资料拟合来确定地层参数和预测,也可用来研究不同工作制度、完井方式,以及增产措施改善情况下的产能变化,为衰竭式开采的气藏工程研究提供了先进的手段.     

冷却排管的节能设计

从节能的观点出发，根据热力学原理和传递过程的理论，对冷却排管内湍流传热过程进行分析，研究损失随雷诺数的变化规律，探讨冷却排管的节能设计问题。