永磁屏蔽泵的电磁场模拟分析

为提高永磁屏蔽泵的性能和缩短设计周期,以一永磁屏蔽泵为例,采用有限元Ansoft软件对永磁屏蔽电动机内部磁场进行了电磁场模拟分析.比较了2种不同内置磁路结构的磁场模拟结构,并分析了定转子气隙大小和屏蔽套等参数对整个永磁屏蔽电动机性能的影响,提出了永磁屏蔽电动机内置倒U形磁路结构合理性及改进屏蔽套设计的途径.研究了定子、转子屏蔽套内部磁涡流分布情况,并针对4种不同屏蔽套材料求解得到定子、转子屏蔽套涡流损耗数值.结果表明:屏蔽套内部存在对称分布磁涡流,定子屏蔽套上涡流分布较为集中,转子涡流损耗明显低于定子屏蔽套;定子、转子屏蔽套采用不导磁材料HASTELLOY-C能耗损失较小,满足设计要求.     

GT干涉仪压缩光脉冲的理论和实验研究

对增益开关半导体激光器产生的有啁啾光脉冲经ＧＴ干涉仪的脉定压缩效应进行了理论和实验研究。ＧＴ干涉仪由相互平行的全反射镜和部分反射镜组成。干涉仪的反射率恒等于１，其色散曲线呈周期性变化。在一个周期内，色散有正有负。调节二镜间距，使其具有适当的色散特性，可用来压缩光脉冲。理论计算和实验结果均表明，压缩后光脉冲形状随ＧＴ干涉仪反射镜间距的变化而变化。在某种情况下，光脉冲呈分裂状。在适当的条件下，可得到很好的压缩效果。实验得到最窄光脉冲的脉宽为 ５．５ ｐｓ，压缩比为 ８．４。     

非正式群体:构建和谐校园的新平台

构建社会主义和谐社会成为目前党和国家最为重要的任务,而构建和谐校园是这项任务中的重要组成部分。本文在分析了非正式群体在构建和谐校园过程中的积极作用后,认为可以借助非正式群体这个有利的平台,采取相应的措施来构建和谐校园。     

Calibration of the HSPF model with a new coupled FTABLE generation method

The hydrological simulation program FORTRAN (HSPF) is a comprehensive watershed model designed to simulate water quantity and quality processes.It is used widely throughout the world.Calculating discharge from a stream reach by HSPF is based mainly on function tables (FTABLEs),which describe the relationship between surface area,stream stage,volume,and discharge.The traditional method of FTABLE generation (using general stream cross-sections and the Manning equation or other discharge relationships) can be time-consuming and inaccurate when there are limited calibration stations and survey data.Recent insights into generalized coupled stage/storage and stage/discharge relationships,however,offer the potential to improve both the speed and accuracy of compiling FTABLEs and thus HSPF models.This study tested the application of these insights in generating FTABLEs.The study domain included 18 gauging stations in a coastal plain environment on the Peace River watershed in West-Central Florida.In the calibration of this model,wetlands were treated as reaches in HSPF with storage-attenuation characteristics.Over the simulation period,the modeled daily flow and stage correlated well with observed data at all ganging stations along the Peace River.The Nash-Sutcliffe efficiency and correlation coefficient computed using observed and simulated daily flows were 0.90 and 0.91,respectively,at the Peace River outlet.Rigorous testing found that the new system for calibrating the FTABLEs improved the model predictive ability and efficiency.Uncertainty in un-calibrated station performance was also reduced.The model parameters obtained in this study could potentially serve as reference values for model application in similar climatic regions.They may also have particular relevance in disaster management,as the simulation period extended over the hurricane season of 2004,and the model domain was within a high hurricane impact zone.The possible effects of hurricanes on discharge are also briefly discussed.     

东秦岭松树沟长英质高压麻粒岩的原岩性质

地球化学特征研究表明,东秦岭松树沟长英质高压麻粒岩的原岩性质主体为杂砂岩或长石砂岩,少量为亚碱性的酸性火山岩或岩浆岩并具慢源成因;其古构造环境类似于活动大陆边缘。     

基于知网的文本标注

知网（英文名称HowNet）是一个以汉语和英语的词语所代表的概念为描述对象,以揭示概念与概念之间以及概念所具有的属性之间的关系为基本内容的常识知识库,本论文以知网中的知识词典为资源,以两篇真实文本为示例,研究基于知网的文本标注,以探讨知网知识在中文信息处理中的作用。     

Evidence for ubiquitous strong electron-phonon coupling in high-temperature superconductors

Coupling between electrons and phonons (lattice vibrations) drives the formation of the electron pairs responsible for conventional superconductivity. The lack of direct evidence for electron-phonon coupling in the electron dynamics of the high-transition-temperature superconductors has driven an intensive search for an alternative mechanism. A coupling of an electron with a phonon would result in an abrupt change of its velocity and scattering rate near the phonon energy. Here we use angle-resolved photoemission spectroscopy to probe electron dynamics-velocity and scattering rate-for three different families of copper oxide superconductors. We see in all of these materials an abrupt change of electron velocity at 50-80 meV, which we cannot explain by any known process other than to invoke coupling with the phonons associated with the movement of the oxygen atoms. This suggests that electron-phonon coupling strongly influences the electron dynamics in the high-temperature superconductors, and must therefore be included in any microscopic theory of superconductivity.