Shallow Turbulent Flows by Video Imaging Method

Shallow turbulent flows were produced in a tank of small thickness to study the friction effects on large-scale turbulent motion of small depth. The tank was constructed of two parallel walls. The space between the parallel walls (4.4, 1.57, and 0.59 cm) was small compared with the height (107 cm) and the width (212 cm) of the tank, and was varied during the experiments for different friction effects. Turbulent flows were produced by the injection of water in the form of starting jets into the tank filled with water. The large-scale turbulent flow in the small space between the walls of the tank is confined to essentially two-dimensional motion, and the motion is retarded by the force of friction. Dye was injected with the source fluid as the tracer for the highly unsteady and quasitwo-dimensional turbulent motion. From the initiation of the turbulent motion at the source to the final interaction of the jets with the tank bottom, the entire sequence of events was recorded by a pair of video cameras. The depth-averaged concentration of the dye was analyzed using the recorded video images.     

对国企人才资源管理的几点思考

人力资源管理中的人才资源管理是现代企业面临的一个重大挑战。国企中的人才资源管理需要不断进行观念创新，正确认识人才的流动，人才的识别选拔、人才的能上能下、人才的文化物质需求、人才的培育评价、人才的使用储备。     

吉林闹枝金矿床黄铁矿的标型特征研究

从成因矿物学及找矿矿物学的观点出发，系统地研究了闹枝金矿床黄铁矿的形态、粒度、化学成分、热电性、硫同位素方面的标型特征，为矿床的成因研究和深部远景评价提供了矿物学依据。     

数字多媒体广播技术现状及前景

数字多媒体广播（DMB）是从数字音频广播（DAB）基础上发展起来的一种新型广播技术。数字音频广播是在调幅AM和调频FM之后的第三代广播技术。通过对数字多媒体技术的介绍较全面地阐述了其技术系统、功能、现状及发展前景。     

A Family of Far‐Infrared‐Transmitting Glasses in the Ga–Ge–Te System for Space Applications

Conditions of formation of bulk tellurium chalcogenide glasses, containing 70–80 at % Te associated to Ga and Ge are described. The characteristic temperatures are measured: the glass‐transition temperature, T_g, is situated in the range 140–185 °C and the difference T_x – T_g, where T_x is the onset crystallization temperature, is in the range 76–113 °C. Moreover, the optical transmission window is exceptional, ranging from 1.99 μm in the bandgap up to 28 μm in the phonon region. Developed within the framework of requirements for the Darwin mission (a search for and study of extrasolar planets), feasibility of infrared optical fibers formed from these glasses is studied. Drawing experiments are conducted with the glass Ga₂‐Ge₃Te₁₅, which possesses the maximum T_x – T_g, and a first optical fiber is presented.     

Exact integration in the boundary element method for two-dimensional elastostatic problems

This paper derives the exact integrations for the integrals in the boundary element analysis of two-dimensional elastostatics. For facilitation, the derivation is based on the simple forms of the fundamental functions by taking constant, discontinuous linear and discontinuous quadratic elements as examples. The efficiency and accuracy of the derived exact integrations are verified against five benchmark problems; the results indicate that the derived exact integrations significantly reduces the CPU time for forming the matrices of the boundary element analysis and solving the internal displacements.     

An alternative method to compute the component fractions in the geometrical optical model: visual computing method

A method called visual computing was used to solve angular four-components' proportions and directional vegetation cover fraction for discrete canopies and continuous row-planted plants. It proved effective to predict the angular characteristics on pixel scale. The method could be an alternative way to a classical solution of geometrical optical models. A visual computing method would be effective especially when the canopies' spatial distribution and shapes were irregular and could not be described statistically.     

平面波谱法分析电磁波在管道中的传播

通过分析电磁波从管道开口耦合进入管道的绕射机理及场在腔体内的射线特征，将进入管道的绕射场展开为平面波谱，利用平面波在自由空间的传播特性分析了电磁波沿管道的传输和反射特征。通过算例验证了该算法的有效性。     

在ad hoc网络中一种新的节能路由切换模型

提出了一种基于能量消耗的路由切换模型(ERHM),它在路由维护中利用切换技术来使路由的能量消耗最小.仿真结果表明采用切换技术的ERHM模型的能量节省量要比不采用切换技术节约1.5～7.5倍,且节点的移动性越大,能量节约越多.     

SiCf/SiC陶瓷复合材料的研究进展

SiCf/SiC陶瓷复合材料具有良好的力学性能、高温抗氧化性和化学稳定性，是航空航天和原子能等领域理想的新一代高温结构材料。本文概述了增强体SiCt的发展状况及存在的问题，对SiCt/SiC材料的制备工艺、界面相的研究状态、材料的损伤破坏机理和目前的应用研究进展做了综述，并分析了SiCf/SiC陶瓷复合材料的研究重点和发展前景。