SBVERAL PROBLEMS ON BACKANALYSIS OF LANDSLIDE WITH A VARIATIONAL METHOD

The shape,position and stress distribution on the sliding surface can be rationallydetermined by a variational method.And the method satisfies the equilibrium,yield condition and thetransversal conditions for the unknown position to determine the critieal height of a slope when theslope angles and the material parameter C and are known.This paper corrects some ertors existingin the current literature and presents two curves to facilitate deterimination of the critical height andthe cracking position appearing on the top surface of the slope.These curves are particallarly suitedto backanalysis of landslide when the cracking position,the originally slope angle and the failuredslope height are known or can be estimated.Finally,calculated examples are cornpared with currentliterature.     

ANALYSIS OF NONLINEAR PROBLEMS OF LAMINATED PLATES BY USE OF PERTURBATION AND WEIGHTEDRESIDUAL METHOD

This paper solves the geometrically nonlinear problems of symmetric, cross-ply laminated anisotropic rectangular plates subjected to uniformly distributed load by the higher-order shear deformation theory and taking an advantage of the perturbation and the weightedresidual method. First, with the help of the perturbation, the nonlinear partial equations have been changed into linear ones. This paper can solve these linear ones by the weighted-residual method. The combination of quintic B-spline functions are chosen as the basis of trial function and Dirac delta functtion, the weighted function. The method used in this paper is simple, direct and efficient. The numerical results show a good convergence and they are in good agreement with the available data.     

TO SOLVE PROBLEMS OF STRUCTURAL RELIABILITY BY MONTE CARLO METHOD

This paper uses simple and clear mathematical proving to expound the fundamental principle,usage and prospect of Monte Carlo method. This paper also gives an example which explains how Monte Carlo method is used for analysing structural reliabilty of engineering.     

APPLICATION OF DECOMPOSITION COORDINATION METHOD OF LARGE - SCALE SYSTEMS AND METHOD OF NONLINEAR PROGRAMMING TO ECONOMIC SCHEDULING OF POWER SYSTEM

In this paper,we discuss a mathematical mode) for optimization of active power dispatch of large-scale hydro-thermal power systems with cascaded hydropower stations. The following factors are taken into account: the variation of the head in the hydropower stations, water transport delay between cascaded stations etc. Using the decomposition-coordination method of large scale systems, we obtain a three-layer-hierarchical coordination system and a three-layer-hierarchical computational structure. We also discuss the computational methods which are used by each hierarchy. We have taken a test computation and analysing the result of an actual hydrothermal power system. The computational results show that it may obtain a satisfactory economic benefit. The paper provides some research work on the economic scheduling of hydrothermal power systems by the decomposition-coordination method of large-scale systems,multiplier method and a new variable metric method.     

银盐法测定稻谷中无机砷含量的不确定度评定

按GB/T5009.11-2003《食品中总砷及无机砷的测定》无机砷测定中第二法银盐法要求对稻谷中无机砷的含量进行检测,并评定了检测结果的不确定度。评定发现最终不确定度来源主要来自于标准曲线引入的不确定度和重复性实验引入的不确定度。     

PAYING ATTENTION TO USE SIMPLEX METHOD FOR OPTIMAL MULTIPARAMETER IN THE DESIGN OF CONTROL SYSTEM

In the design of control system using simplex method for optimal multi-parameter,if the difference in number between the greatest and the smallestparameters is very great,the optimization process converges very slowly.Evenoptimal parameters can't be found at all.This paper studies the problem,analyses its cause and poses a resolution means.A testing example shows thatthis means can solve the above problem well.     

标准加入直读法快速测定南阳彩色小麦面粉中硝酸根的研究

为了建立一种快速测定小麦面粉中硝酸根的新方法,以南阳彩色小麦为材料,用微波快速浸提样品,与超声波浸提法对照,用离子选择性电极标准加入———浓度直读法快速测定样品中的硝酸根,并进行了测定条件的优化。结果表明:用二次重复加入标准溶液的方法,测定的回收率为89.5%~102.0%。测定结果的相对标准偏差RSD为2.8%~4.7%(n=11),硝酸根的最低检出限为0.040 mg.L-1,测定的线性范围为0.100~100.0 mg.L-1,相关系数为0.997。该方法具有直观、快速、简便、灵敏、准确、适于现场进行测定的显著优点,结果令人满意。