Study of the Mössbauer effect on rare-earth borided surface layers on pure iron

Journal of Materials Science Letters -     

Study on ancient Chinese imitated GE ware by INAA and WDXRF

Imitated GE ware was one of the most famous products of Jingdezhen porcelain field in Ming dynasty (AD 1368-1644). The exterior features of its body and glaze are very marvelous. Black foot, purple mouth and crazing glaze are the main features of imitated GE ware. Until now, the key conditions of resulting these features are not clearly identified. In order to find the critical elements for firing these features, instrumental neutron activation analysis (INAA) and wavelength-dispersive X-ray fluorescence (WDXRF) were used to determine the element abundance patterns of imitated GE ware body and glaze. The experimental data was compared with that of imitated Longquan celadon and of Longquan celadon. The analytical results indicated that Fe, Ti and Na were the critical elements. The body of imitated GE ware which contains high Fe and Ti are the basic conditions of firing its black body, black foot and purple mouth. The glaze of imitated GE ware which contains high Na is the main condition of producing its crazing glaze. Na is the critical element which enlarges the difference in expansion coefficients between the glaze and body of imitated GE ware. Furthermore, Zijin soil was added into kaolin to make the body rich in Fe and Ti. And something which was rich in Na was used to produce crazing glaze in the manufacturing process of imitated GE ware.     

Analysis of dinosaur samples by nuclear microscopy

Several dinosaur bone and eggshell fossil samples unearthed at different sites in China were analyzed by means of nuclear microscopy. Concentrations and distributions of elements such as Na, Mg, Al, P, S, Ca, Cr, Mn, Fe, Cu, Zn, As, Br, Sr, Y, Ce, Pb and U, etc. were obtained for each sample. The results of quantitative PIXE and RBS analyses show unusually high concentrations of U and Ce in several samples obtained from a period near the K-T boundary (between Cretaceous and Tertiary periods, 65 million years ago), suggesting that some form of environmental pollution could be the cause of dinosaur extinction.     

Pattern analysis of airborne dipole antenna in high-frequency region

The Uniform Geometrical Theory of Diffraction (UTD) has been successfully used in pattern analysis of airborne dipole antenna on the A-5 fighter in high-frequency region. In the analysis, several canonical problems are investigated first, then the complicated problem is calculated with compiling these canonical problems. The numerical results are compared with the experimental data, and good agreement has been seen. The effectiveness and practicality of the present analysis are thus verified.     

Modelling and Simulation of Batch and Continuous Fluidized Bed Dryers

The performance of batch and continuous fluidized solids dryers has been modeled, with allowance for diffusional moisture transport in the dense phase particles and for interstitial gas-to-particle mass transfer within the dense phase, as well as for interphase exchange resistance between gas bubbles and the dense phase. Two types of boundary conditions are employed. Variations of the bed temperature and product moisture content in the bed with time are predicted numerically under various batch drying conditions. Exit product moisture contents, bed temperatures and outlet air humidities are also predicted for continuous drying at various mean residence times. The model can be used for homogeneous as well as bubbling fluidized bed drying. It can be used for a wide range of materials, including cereal grains and granular synthetic polymeric materials.     

碳/环氧复合材料的冲击拉伸

该文研究了T300碳纤维单向增强的环氧复合材料,在应变率从10~(-3)/s到10~3/s范围内的冲击拉伸行为.通过对实验数据进行拟合,得出该范围内材料对应变率具有弱的敏感性,表现在破坏强度及破坏应变随应变率增加不显著变化,平均模量几乎不受应变率的影响.分析了试件的几何尺寸效应,讨论了应力波作用对破坏形态的影响以及实验中观察到的拔出现象.从应变率在10~2～10~3/s附近材料行为某些非确定性,指出在更宽范围内了解其性能的必要性.     

广义de Bruijn多计算机互连网络

（ｄ，ｍ）ｄｅ Ｂｒｕｉｊｎ多计算机系统互连网络限制网络的规模必须为ｄ＾ｍ。本文把（ｄ，ｍ）ｄｅ Ｂｒｕｉｊｎ网络推广到了任意顶点情形，提出了广义ｄｅ Ｂｒｕｉｊｎ网络，研究了广义ｄｅ Ｂｒｕｉｊｎ网络的自路由性质，设计了路由算法，研究了广义ｄｅ Ｂｒｕｉｊｎ网络顶点度的性质和容错特性。     

层次式级联多网络模型及其性能

本文提出了一种层次式级联多网络结构，论述了其训练算法，并验证了该结构的收敛性。这种结构在处理高阶非线性分布数据的分类问题方面具有优良的性能，用北京谱仪事例过滤进行性能测试结果表明，其训练和泛化性能都优于单个ＢＰ网络。     

游梁式抽油机曲柄销所受扭矩分析

在分析游梁式抽油机连杆大头轴承座因装配不当而产生变形的基础上，用有限元法分析了轴承所受的径向力，得出了曲柄销上所受的扭矩。最后，以ＣＹＪ１０－３－５３ＨＢ游梁式抽油机曲柄销为例进行计算，得出当轴承座径向变形量为０．１ｍｍ时，曲柄销中相应产生的扭矩可达１．０８ｋＮ·ｍ。为消除这种不良影响，应考虑采用其他的联接方式，以避免装配时产生过大的装配应力。