Al_(66)Mn_(14)Si_(20)合金条带的电学性质研究

本文报导了退火温度对Al_(56)Mn_(14)Si_(20)急冷条带的电阻-温度系数的影响。在77～300K温区内电阻-温度系数发生了从负到正的转变。差热分析、电子顺磁共振、X射线和电子衍射实验表明:该现象对应着样品中的非晶相晶化的过程,变化中电子态由局域态转变成扩展态。在电子衍射实验中还见到了一种具有12重对称性的电子衍射花样。     

三维立体零件几何造型试验系统研究

介绍了一个三维零件几何造型的试验系统,系统具有体素构型功能、集合运算功能和消除隐藏线功能。最后,给出若干实例。     

Ferroelectricity of weak-polar organic molecules in alternate Langmuir-Blodgett multilayer films

Pyroelectric material is a polar solid and has been interested since the 1960s. Today it is one of important materials used in infrared detectors[1]. With the development of the devices, the focus point on the materials applied has been transferred from bulk materials to film ones. Ferroelectric material is a kind of pyroelectric materials which spontaneous polarization can be reversed with the direction change of external electric field. Observation of ferroelectric hysteresis loop or not cou…     

Post-collisional extensional and thrust-nappe structures in northern part of Dabie Mountains

Thrust-nappe structures and extensional structures simultaneonsly occur in the northern part of the Dabie Mountains. The systematic structural study reveals that extensional structures along the Mozitan-Xiaotian fault and thrust-nappe structures that take the Jinzhai-Shucheng fault as their frontal thrust share the same shear sense, and display a transitional relationship from the ductile extensional structure of deep level in the south to the ductile-brittle and brittle thrust-nappe structure of shallow level in the north. The extensional and thrnst-nappe structures in the region are explained to result from post-collisional processes by the continuous subduction of the Yangtze continental block and the extension induced by the uplifting of the core part of the Dabie Mountains, which are components of the exteasional structures produced in the exhumation process of the ultrahigh pressure metamorphic rocks in the Dabie Mountains. Because of the frontal blocking in the process of the north-westward spreading, the extension and detachment of the low-grade metamorphic rocks along the Mozitan-Xiaotian fault was transformed into the northwestward thrustiag, resulting in the thrust-nappe structures. They developed in the period of 200-170 Ma, maybe last till the late Jurassic.     

温度对Cu-Zn二元系粉末机械合金化的影响

将Cu-40%Zn(40%为质量分数)二元系粉末在-30℃和常温下进行高能球磨,并利用X射线衍射仪及扫描电子显微镜对球磨过程中的组织演变过程及微观形貌进行了研究.研究结果表明:Cu-40%Zn二元系粉末的机械合金化过程是一个Cu向Zn中扩散、固溶与反应的过程,最终产物为Cu0.64Zn0.36(α相)与少量的ZnO相;低温球磨合金粉末的晶格畸变量与晶粒尺寸都比常温球磨的大;与常温球磨不同,低温球磨可以抑制冷焊所带来的不良影响,避免添加过程控制剂,而且体系呈现脆性-脆性特征.     

基于网格的医疗信息集成及图像处理应用

针对目前医院信息系统中存在的信息孤岛现象,提出了基于网格技术和网格工具的解决方案,研发了基于中国网格公共支撑平台(CGSP)的医学图像网格平台MedImGrid,互连各种异构医疗资源,有效整合分布在各家医院和医疗研究机构的大量医疗数据与信息,实现了对异构医疗信息、病例图片、医学专家知识等信息资源的共享和集成,为用户提供广域范围内的医疗信息查询和病例图片检索,并支持基于断层图片的三维重建、基于特征值的图像检索与辅助诊断等医学图像处理应用.     

基于J2EE技术的数字化校园架构设计

提出并设计了一个典型的数字化校园系统整体架构的方案 .结合网络教学子系统 ,给出了J2EE技术的具体实现 .结果表明 ,将J2EE技术用于构建数字化校园系统 ,对节省系统设计和开发时间、提高系统安全性、可维护性、可扩展性等都具有明显效果     

动力定位自动区域保持控制策略研究

根据动力定位自动区域保持控制系统的要求 ,设计了多种控制方案 ,以能量为指标函数进行比较。仿真结果表明 ,在海况不高的情况下 ,采用一种间断控制纵向、横向 ,始终保持平均最优艏向的控制方法相对最节省能量     

Investigation of stress corrosion-enhanced plastic deformation using atomic force microscope

Atomic force microscope (AFM) was used to study in situ the change in slip bands during stress corrosion of brass in the ammonia solution prior to initiation of stress corrosion crack. The result showed that additive slip bands appeared ahead of a loaded notch tip during stress corrosion prior to initiation of stress corrosion crack after the constant deflection specimen was precrept for 48 h and then polished. The average height and spacing of slip bands generated during stress corrosion were about three times less or larger, respectively, than those during loading in air.