大体积阱式NaI(Tl)探测器的效率计算与测量

使用蒙特卡罗方法模拟计算了一个用于4πγ计数的大体积阱式NaI(Tl)探测器的效率和能谱。采用一系列单能γ源标定探测器,对计算结果进行检验,其结果基本一致,两者间的最大偏差不超过±8%,证明计算结果是可靠的。     

不确定非线性系统控制方法概述

不确定非线性系统的控制是目前国内外自动控制领域研究的一个热点。主要总结了近年来不确定非线性系统的控制方法，并分析了各种方法的优缺点。最后探讨了这一研究领域的研究趋向。     

快速测定化学需氧量的方法

利用分光光度法、微波密封消解法测定水样中的化学需氧量，并把测定的精密度、准确度与国标回流法相比较，结果证明：分光光度法、微波消解法是测定化学需氧量的快捷方法，具有省时、省试剂、工作效率高的特点。     

连续优化问题的蚁群算法研究

蚁群算法是一种新型的模拟进化算法，初步的研究已经表明该算法具有许多优良的性质，对于连续优化问题，提出了基于蚁群算法思想的求解算法，并与网格法作了比较，数值试验结果表明该方法比较有效，并具有通用性。     

A logic-based approach to rule induction in expert systems

Rule induction is an important part of learning in expert systems. Rules can help managers make more effective decisions and gain insight into the relationships between decision variables. We present a logic-based approach to rule induction in expert systems which is simple, robust and consistent. We also derive bounds on levels of certainty for combining rules. We apply our approach to the development of rules for the entry decisions of new products. We then discuss how the logic-based approach of rule induction can be used to create a decision support system and the methodology to create such a system.     

Conjugate filters with spectral-like resolution for 2D incompressible flows

A conjugate filter oscillation reduction scheme originally developed for compressible flows and in general for hyperbolic conservation laws is applied to the solution of the incompressible Navier-Stokes equation with periodic boundary conditions. Conjugate low-pass and high-pass filters are constructed by using a local spectral method, the discrete singular convolution algorithm. A spectral-like resolution, i.e., near the machine precision obtained at a sampling rate close to the Nyquist limit (2 points per wavelength), is achieved in treating a smooth initial value problem which admits an exact solution. The spectral-like resolution is enhanced by the use of conjugate low-pass filters in treating the double shear layer and multi-shear layer problems, which exhibit extremely small flow features.     

A hybrid computational strategy for identification of structural parameters

By identifying parameters such as stiffness values of a structural system, the numerical model can be updated to give more accurate response prediction or to monitor the state of the structure. Considerable progress has been made in this subject area, but most research works have considered only small systems. A major challenge lies in obtaining good identification results for systems with many unknown parameters. In this study, a non-classical approach is adopted involving the use of genetic algorithms (GA). Nevertheless, direct application of GA does not necessarily work, particularly with regards to computational efficiency in fine-tuning when the solution approaches the optimal value. A hybrid computational strategy is thus proposed, combining GA with a compatible local search operator. Two hybrid methods are formulated and illustrated by numerical simulation studies to perform significantly better than the GA method without local search. A fairly large structural system with 52 unknown parameters is identified with good results, taking into consideration the effects of incomplete measurement and noisy data.     

对多孔介质物体孔隙度-蜡封法改进的探讨--以土壤团聚体为例

融资难问题已成为中国中小企业发展的桎梏。当前 ,在中国资本市场欠发达的金融体系下 ,间接融资无疑是中小企业最佳的融资途径。然而 ,长期以来 ,国有商业银行却忽视了对中小企业的信贷支持,要涉足这一领域,在“以市场为导向 ,以客户为中心,以效益为原则,以风险控制为主线”的信贷经营思想指导下,必须进行面向中小企业的信贷业务创新和组织结构调整     

乳状液型液膜法处理含锌废水的动力学

乳状液型液膜法以其去除效果好、回收率高、处理量大、消耗低等特点，在废水治理中得到了广泛的应用。本文采用该法对含锌废水进行处理，取得了较好的效果。在此基础上，通过对分离过程动力学的研究，确定了速控步骤的动力学方程，从理论上探讨了载体和废水中锌离子浓度，以及分离温度对分离速度和分离效率的影响，并在实验中得到了验证。该动力学方程的建立，不仅为含锌废水的处理提供了依据，也为计算机模拟该过程奠定了基础。     

含化学反应体系多相平衡计算方法的研究进展

首先给出了含化学反应体系多相平衡计算问题的数学方程，然后对国内外含化学反应体系多相平衡计算方法的现状和进展做了综述，包括经典的非化学计量系数法和化学计量系数法以及最近提出的稳定性分析法、全局最优法和遗传算法等，并具体介绍了化学计量系数法中两种常用算法-S-C算法和KZ算法以及遗传算法的算法原理和计算步骤。