焦耳效应标定高温卡尔维微量热计

根据热流式量热计的Tian氏方程,用焦耳效应标定高温卡尔维微量热计。用偏差法得到的灵敏度值与积分法测得的值一致。用回归曲线对灵敏度实验值进行拟合,利用计算机求得灵敏度—温度回归曲线,得到了室温至700℃的全部灵敏度值,从而即可使用微量热计测量此温度范围内的未知样品热效应。     

A numerical scheme for calculating stresses and strain rates in glaciers

The stress and strain-rate fields in a glacier or other type of rock with known rheological properties can be calculated by using a numerical solution technique. Calculations are based on force-balance equations and the constitutive relation for polar ice, and do not involve any mathematical approximations. The geometry is prescribed. Basal velocities also are prescribed, either by specifying their values or by relying on a sliding relation. All other quantities are determined numerically.     

An application of Karmarkar's interior-point linear programming algorithm for multi-reservoir operations optimization

Optimization of multi-reservoir systems operations is typically a very large scale optimization problem. The following are the three types of optimization problems solved using linear programming (LP): (i) deterministic optimization for multiple periods involving fine stage intervals, for example, from an hour to a week (ii) implicit stochastic optimization using multiple years of inflow data, and (iii) explicit stochastic optimization using probability distributions of inflow data. Until recently, the revised simplex method has been the most efficient solution method available for solving large scale LP problems. In this paper, we show that an implementation of the Karmarkar's interior-point LP algorithm with a newly developed stopping criterion solves optimization problems of large multi-reservoir operations more efficiently than the simplex method. For example, using a Micro VAX II minicomputer, a 40 year, monthly stage, two-reservoir system optimization problem is solved 7.8 times faster than the advanced simplex code in MINOS 5.0. The advantage of this method is expected to be greater as the size of the problem grows from two reservoirs to multiples of reservoirs. This paper presents the details of the implementation and testing and in addition, some other features of the Karmarkar's algorithm which makes it a valuable optimization tool are illuminated.     

Evaluation of rainfall-runoff performance using the stochastic integral equation method

The stochastic integral equation method (S.I.E.M.) is used to evaluate the relative performance of a set of both calibrated and uncalibrated rainfall-runoff models with respect to prediction errors. The S.I.E.M. is also used to estimate confidence (prediction) interval values of a runoff criterion variable, given a prescribed rainfall-runoff model, and a similarity measure used to condition the storms that are utilized for model calibration purposes.Because of the increasing attention given to the issue of uncertainty in rainfall-runoff modeling estimates, the S.I.E.M. provides a promising tool for the hydrologist to consider in both research and design.     

二维不均匀介质中点源P-SV波响应的有限差分近似算法

本文从一阶方程组形式的波动方程出发,发展了一种计算二维不均匀介质中点源P-SV波响应的近似方法。该方法通过引入线分布的应力作为震源,利用二维有限差分方法计算出线源响应,然后再经过波形校正和几何扩散校正得出相应的近似点源响应。通过把波形和振幅与精确解比较表明,该方法具有较好的精度。由于有限差分方法对于介质中速度和密度的分布没有特殊要求,另一方面,本文所给出的震源可以适用于位错点源、爆炸源或集中力源,因此上述方法十分适合于研究横向不均匀介质中的近场强地运动、爆炸振动或地震勘探等问题。     

非线性弹性模型的改进

本文在邓肯-张模型进行深入探讨的基础上,提出了切线模量实质物理意义是剪切模量的观点,并分别采用应力法和应变法推导了剪切模量和体积模量(或变形模量)公式,还进行了考虑Biot固结非线性弹性油罐地基有限元实例分析。对不同的变形模量计算方法进行了比较,提出了改进的非线性弹性模型。     

求解非线性有限元方程的弧长法及在工程稳定分析中的应用

本文讨论了求解非线性有限元方程弧长法的基本原理及具体实施,并应用于压杆及滑块的稳定性分析。由于弧长法具有确定并通过结构临界应力状态的临界荷载值,因此可以应用于工程稳定性分析。算例表明,弧长法确定的临界荷载值是令人满意的。     

遥感筛选评价区化异常的初步探索

近年来,作者发展了七种以上重要找矿指示元素的野外快速分析法,此乃其一。文中提出一种新的金样冷浸技术,引进了新的光导光度检测方法,样品经溴化钠—硫酸—过氧化氢冷浸,用经丙酮—MIBK处理的泡沫塑料富集金,经混合解脱剂解脱并直接取解脱液用改进的微珠析出法或用光导光度法测定。取10g样品,可测定0．0005- 50g/t范围内的金。方法简便、快速,可在普查分队驻地进行,每一工作日可测定80多个样品,由于废弃了王水分解样品和泡沫塑料的灰化,具有广阔的应用前景。