EFFECT OF HIGH LOADS IN THE BRIDGE LOAD SPECTRUM ON FATIGUE CRACK GROWTH OF 16 Mn STEEL

This paper studies an effect of high loads in Rayleigh distribution random load-ing on fatigue crack growth wi th 16 Mn steel compact tenion specimen,The results show that thehigh loads in the load spectrum close to service load of steel bridges accelerate crack growth and re-duce crack growth life,Lives predicted with constant amplitude da/dn data and equivalent loads arequite in agreement with test lives.     

Spline Boundary Element Method for Calculating Three-Dimensional Electrostatic Fields

Based on [l].this paper presents a new spline-BEM for calculating 3-D electrostatic fields,in which bi-cubic B-splines are used as basis functions. The corner problem in BEM and the extreme conditions for splines are circumvented. The numerical results presented show that the global approximation .convergence and stability of the method are satisfactory.     

The Stability of Quaternion Metrices and Their Judging Criteria

Some conceptions of stable quaternion matrices and some judging criteria are given.The Robrach theorem,Taussky theorem,Ostrowski Schneider theorem and Gerschgorin theorem are generalized to quaternion field.The conclusion about two quaternion matrices,i.e.,inferior positive matrices are unstable,interior negative matrices are stable and some other results are pointed out.     

FDTD Method''s Application in the Research of Television Interference From High Voltage Transmission Line

The mechanism of television interference is discussed from High voltage transmission line. Then the computational model is established, and scattering fields are calculated with the finite-difference time-domain(FDTD) method, and the results are visualized. The scattering effects of High voltage transmission lines on horizontal polarization waves (corresponding to TM mode) are greater than on vertical polarization waves (corresponding to TE mode).     

Nonlinear Finite Element Analysis of RC Deep Flexural Simply Supported Beams Using Disturbed Stress Field Model

A nonlinear finite element analysis of 4 RC deep flexural simply supported beams with the program VT2 is presented. Crack development and failure modes , longitudinal reinforcement strain distributions and load -deflection curves were compared as a result in order to evaluate the validity of the disturbed stress field model to analyse such deep simply supported beam.     

A NEW METHOD OF RESEARCHINE THE SITE DUPLE FACE DYNAMIC BALANCE OF MACHINE RIGID ROTATOR BASE DON AMPLITUDE MEASUREMENT

In this paper, a new method of researching; the site dupleface dynamic balance of machine rigid rotator, namely duple test weightmethod is presented. Weight the new method against the existing method,namely single test weight method [1], both the efficiency increasing and theenergy-consumming dicreasing would be forty percent and over, with thebasic points of vibration theory, the formula of calculating weight andposition of the duple face dynamic unbalance of a rotator by means ofapplying the duple test weight is developed in detail. The method in handll-ing distinct bearing form is also discussed. Rightness of the new method isproved out by the living example of the simulant contrast testing carried outn the dynamic balance test machine and the site balance for a rotatorsystem of motor.     

北方旱地土壤氮素平衡

北方大部分地区的旱地土壤中,农业氮素一般表现亏损,平衡强度约87%;园田土壤氮素略有盈余,平衡强度约123%.~(15)示踪研究表明,旱地土壤主要作物氮素利用率平均为27.04%,土壤残留24.79%,亏缺损失48.17%.园田主要蔬菜氮素和用率平均为29.11%,土壤残留22.67%,亏缺损失48.23%,其间差异很小.北方旱地施用铵态氮化肥主要损失是氨的挥发.影响氨挥发的因素有风速、温度、土壤水分、土壤质地、化肥品种.氮肥深施是防止氨挥发的有效方法.     

切线泵流动特征的整流场数值模拟

对单级切线泵在设计工况进行了定常流动数值模拟，分析了叶轮流道及蜗壳内的液体流动情况。结果表明，切线泵内流场非常复杂，叶轮进口有明显冲击，叶轮各流道的速度、压力差异很大，环形蜗壳内流动呈现旋涡推进特征，上、下游流动有强烈的相互作用，整机流场不具有对称性；环形蜗壳的几何结构以及流场上、下游的相互作用是导致整机流场非对称特性的主要原因。计算结果为进一步改进结构、提高性能、减小水力损失提供了理论依据。     

喷油泵试验台智能量油系统的研究

为解决喷油泵试验台量油系统测量误差较大的问题，本研究通过采集喷油器针阀升程、喷油压力、转速等信号精确测得喷油量。