巧解铅球最佳出手角

利用运动叠加原理通过对铅球运动的恰当分解, 提出了一种计算最佳出 手角的新方法, 并与传统方法就两种不同情形进行了对比, 说明了新方法的物理思想.     

高层建筑TMD风振控制优化设计

本文探讨了高层建筑TMD风振控制优化设计方法,研究了高层建筑TMD风振控制最优参数取值问题,给出了高层建筑TMD风振控制设计步骤,最后给出了算例说明及其应用。     

包含两类变量的离散变量桁架结构拓扑优化设计

建立了包含截面和拓扑两类变量的离散变量结构拓扑优化设计的数学模型,该模型考虑了截面变量与拓扑变量间的耦合关系,反映了拓扑优化问题的组合优化本质,可以较好地解决"极限应力"、"最优解的奇异性"等困扰结构拓外优化设计的问题．同时采用相对差商法进行离散变量桁架结构拓扑优化,直接求解包含两类变量的离散变量结构拓扑优化设计数学模型,收到了比较满意的效果．     

带鳍通道性能的遗传算法优化

与光滑通道相比,带鳍通道有更高的传热系数,附加的鳍,极大地增强了通道的传热.然而,传热的增强又与压降的升高相关联,这又导致泵动力需求的增加,因此应该寻求对该系统的优化设计.该文的主要目的是,通过如下方式来精确地确定鳍的位置和尺寸:利用遗传算法实现最小压降时达到最优传热.鳍的每种布局作为问题(遗传算法中的一个个体)的一个解.通常,首先随机地产生一个初始种群,然后该算法在所有这些解中搜索,利用布局函数迭代出新解,最后得到鳍的优化设计.     

On the quasistability of trajectory problems of vector optimization

We consider quasistable multicriteria problems of discrete optimization on systems of subsets (trajectory problems). We single out the class of problems for which new Pareto optima can appear, while other optima for the problems do not disappear when the coefficients of the objective functions are slightly perturbed (in the Chebyshev metric). For the case of linear criteria (MINSUM), we obtain a formula for calculating the quasistability radius of the problem. Translated fromMatemalicheskie Zametki, Vol. 63, No. 1, pp. 21–27, January, 1998. This research was supported by the Belarus Foundation for Basic Research under grant No. F95-70.     

Optimum design of vibrating cantilevers: A classical probem revisited

Optimum design of vibrating cantilevers is a classical problem widely used in the literature and textbooks in structural optimization. The problem, originally formulated and solved by Karihalloo and Niordson (Ref. 5), was to find the optimal beam shape that will maximize the fundamental vibration frequency of a cantilever. Upon reexamination of the problem, it has been found that the original analysis and solution procedure can be simplified and improved substantially. Specifically, the time-consuming inner loop devised for solving the Lagrange multiplier in the original work has been proved to be tolally unnecessary and thus should not be considered in the problem solution. This conclusion has led to a new set of simplified equations for the construction of iteration schemes. New asymptotic expressions for the optimum design solution have been obtained and verified by numerical results. Numerical analysis has shown a significant improvement in convergence rate by the proposed new procedure. Also some obvious numerical errors in the original paper have been identified and corrected.This work was suppoted in part by the University of Arizona Foundation and the Office of the Vice President for Research. The author is grateful to the reviewers for their valuable comments.     

An ordering (enumerative) algorithm for nonlinear 0-1 programming

In this paper, a new algorithm to solve a general 0–1 programming problem with linear objective function is developed. Computational experiences are carried out on problems where the constraints are inequalities on polynomials. The solution of the original problem is equivalent with the solution of a sequence of set packing problems with special constraint sets. The solution of these set packing problems is equivalent with the ordering of the binary vectors according to their objective function value. An algorithm is developed to generate this order in a dynamic way. The main tool of the algorithm is a tree which represents the desired order of the generated binary vectors. The method can be applied to the multi-knapsack type nonlinear 0–1 programming problem. Large problems of this type up to 500 variables have been solved.     

结构优化设计的KFD方法及其在电除尘器本体结构优化中的应用

电除尘器本体结构优化设计是一个规模大,设计变量数多而具有相当难度的几何可调和拓扑可调优化设计问题。对这样一个大型复杂的结构优化问题,本文在文[1]的工作基础上,充分利用结构的力学特性,应用有效设计变量的概念,建立了不用求偏导数且不必解线性规划的可行方向法—KFD方法。该方法具有收敛速度快、占用内存少的优点,比通常ε有效约束可行方向法提高速度数十倍。实际应用的结果表明文中的方法是很有效的。     

脉冲快放电激励S2激光器电源的研究

选择Blumlein电路作为放电电源的主电路,建立了Blumlein电路的离散化等效模型,利用该模型对电路进行仿真研究与优化设计,选取一组电路元件参数作为装调放电电路的依据,设计并制作了传输线电容与储能电容器,大大减小了电路寄生参数,提高了电路性能。实验结果表明,该放电电源的输出电压上升沿达到5.08 ns的设计指标,且工作稳定,对激光器的正常工作起了重要的作用。     

电子束在气体中传输的最佳压强研究

推导得到了有外加磁场情况下强流相对论电子束在中性气体中产生的等离子体参数、等离子体电流和束产生电场的理论公式,通过编程计算得知最佳气体压强值随电子束峰值电流的增大而增大,电子束脉冲前沿上升越快最佳气体压强值就越高,当电子束的峰值电流为500kA、峰值电压为1.0MV、电流脉冲前沿上升时间为60ns时,氮气的最佳压强为332Pa,即当气压为332Pa时净电流和平均电场强度近似最低,有效传输的气压范围约为199~532Pa。实验结果与理论计算符合很好。