超音速燃气射流非定常波系的数值研究

根据ＭＵＳＣＬ格式的基本思想，对格式进行了部分修改，数值模拟了超音速燃气射流流场的结构和发展过程。给出了流场谐波系的变化趋势，得到了流场达到稳定状态的时间和稳定后的流动图形。     

The relative permeability of concrete using nitrogen gas

A modified version of a test, originally proposed by BRE (UK), was used to assess relative permeability to nitrogen gas of concretes cured in various ways. Three simple parameters from test plots clearly showed the effects of duration of water curing, followed by drying to constant mass at 50°C; test specimen moisture content was dominant and drying at 105°C reduced differences between concretes of very different quality. Convincing evidence was not found of differences between upper and lower ‘halves’ of cylinders nor between cast and cored ones.     

THE STATISTICAL DISTRIBUTION OF EXTREME VALUES OF WAVE-CURRENT FORCES ACTING ON SLENDER CIRCULAR CYLINDER IN IRREGULAR WAVES

Based on model test,the statistical distribution of extreme values of wave-current in-line forces acting on vertical circular cylinder is analyzed in this paper.It is shownthat the results calculated by the simplified method,proposed by authors,agree well with the testdata;Weibull distribution is also adoptable in the region of high KC number, and the shapeparameter a and scale parameter β are related well with KC number respectively.     

瞬态瑞利面波技术在地震勘探方面的应用研究

运用瞬态瑞利面小勘探方法可以在寻找激发岩性和提供静校正所需参数方面取得好的效果。     

用超声波技术测量螺栓轴向紧固应力

超声波速度会因材料中加载应力而产生微小的变化，这一现象特别适用于测量螺栓的轴向应力。根据螺栓的轴向应力与超声波传播时间变化率的关系，作者研究了一种可直接测量螺栓轴同应力的仪器。实验结果显示，本项技术十分适合现场的实际应用。     

冲击能传感器的研究与分析

本文分析并推导了应力波在弹性体中传播时,质点的运动速度、压力、位移及应力载波的聚流的形成与表达式.利用得到的公式描述了冲击能传感器的工作机理.给出了某风动工具的测试结果.     

基于属性相关表的关系模式全部候选关键字求法

本文提出了属性相关表这样一种新的概念，定义了相应的运算并研究了它的有关性质及定理，在此基础上提出了用属性相关表求关系模式全部主属性的等级，并给出了用主属性来组合关系模式全部候选关键字的算法，上述算法的时间复杂度均为Ｏ（ｎ＾２）。     

Nonreactive atom/molecule-surface scattering within the finite basis wave packet method

A quantum wave packet code for studying nonreactive scattering of closed-shell atoms or diatomic molecules from a rigid surface is described. The time evolution relies on the Chebychev propagator. Up to 5 collider degrees of freedom, 3 in translation and 2 in rotation, are treated in a pseudospectral way with the momentum or finite basis representation as the primary space. Potential matrix elements are efficiently evaluated by means of sequential 1D transformations between momentum and coordinate spaces. Fast Fourier transforms are performed for the translational and azimuthal coordinates whereas a Gauss-Legendre transform is used for the polar coordinate. This pseudospectral strategy minimizes memory requirements because no off-diagonal Hamiltonian matrix elements need to be stored. In addition, a wide variety of physical systems can be studied since no particular functional form is imposed for the interaction potential.     

管道流体瞬态—水汽锤计算原理

文中介绍了核电站管道中流体瞬态——水汽锤的计算原理;既适用于液体介质的水锤计算,也适用于可压汽体的汽锤计算.对于一些典型管道部件的处理方法,文中也作了讨论。     

Microwave Communication to Moving Parts Inside Machines

Cables to moving parts on a linear actuator in production machines, such as pick-and-place machines, are a source of unreliability owing to the possible breaking of a cable. They further reduce the positioning precision of the actuator owing to additional forces. Slotted waveguide systems for rail vehicles based on 2.4 GHz transmission frequency are well known, but transmitters/receivers and waveguides are bulky. The paper reports on the reduction in size of the equipment, adapted to 5.8 GHz using a commercial off-the-shelf RadioLan communication module. Further, the efficient termination of the wave-guide and a new way to reduce standing-wave effects is also discussed.