基于非线性规划的指数自回归模型的辨识

讨论了指数自回归模型的辨识问题，证明了该模型最小二乘估计的目标函数的非凸性，并给出了使该函数为凸的条件，最后给出了辨识该模型的算法及该算法的收敛性，并以数值例子加以说明。     

直流电动机参数测定

根据直流电机的可逆原理并利用常规的实验仪表，可以简便、准确地测出直流电动机的主要参数－电磁转矩、输出转矩和效率．     

槽孔式水力驱动控制棒槽孔阻力系数实验研究

对槽孔式水力驱动控制棒槽对孔阻力系数进行了大量实验研究，获得了槽孔式水力驱动控制棒槽对孔阻力系数和其随槽对孔位移的变化规律，分析了槽对孔阻力系数与控制棒槽对孔结构参数之间的关系。结果表明：随槽对孔位移的增加，槽对孔阻力系数从某一较大的定值迅速降低到某一较小的定值，然后再迅速反回到初始的定值，形成一个对称的宽幅波谷；槽高使阻力系数曲线波谷幅宽发生变化，也使完全不重合段的阻力系数发生变化；随内套孔径的增大，阻力系数有所降低，其对阻力系数的影响也进一步减弱。孔径增大到一定程度，阻力系数基本不受孔径参数的影响。     

A Primal-dual Steepest-edge Method for Even-flow Harvest Scheduling Problems

The even-flow harvest scheduling problem arises when the forestry agency has evolved into a rigid non-declining even-flow policy. In this paper, we investigate model formulation and solution strategies for the even-flow harvest scheduling problem. A multiple-objective linear programming problem is formulated for even-flow harvest scheduling problems with multiple-site classes and multiple periods. The aim of this problem is to simultaneously maximize a desired harvest-volume per hectare for each period of planning horizon and the total economic return. A block diagonal constraint structure, with many sets of network sub-problems and a set of coupling constraints, is identified in this linear programming problem. A longest path method for each of network sub-problems and a primal-dual steepest-edge algorithm for the entire problem are developed. The developed algorithm has been coded in Borland C++ and implemented on a personal computer. An illustrative example is used to display the detailed procedure for the developed algorithm and a real-world case study is used to show the trade-off between desired even-flow harvest volume policy and total economic return. Results show the potential benefits of this approach.     

Spectral multidomain approximation of elliptic problems with mixed conditions on the interfaces

The multidomain technique for elliptic problems, that allows the fulfillment of the interface conditions by means of a suitable combination of the continuity of the solution and of its normal derivative, is considered. Some choices of this combination are investigated and, in particular, a choice that allows the solution of the multidomain problem through two solutions for each subproblem, is proposed. The scheme has been discretized with a collocation method and some numerical tests are reported. Moreover the method is compared with the more classical Dirichlet/Neumann one as well as with the capacitance matrix method.This research has been supported by a grant from M.P.I. (40%).     

热流法计算高温炉内辐射传热

高温炉内的辐射传热是工业生产中常遇到的问题。过去，人们在应用热流法计算辐射传热时遇到了一定的困难，使计算结果与实际有一定的偏差。本文运用文献［１］中给出的新热流数学模型，开发出由新热流方程与能量方程相耦合的计算机程序，其中的比热流参数由线加热热源情况下计算得到。用该程序计算了实验室用马弗炉内的温度场，并且用热电偶实测了炉内的一些温度值，理论计算与实测值符合很好。     

A feasibility study of a direct-mapping parallel processing method to solve linear equations in load-flow calculation

With the growing size and complexity of power systems, system analysis—such as transients calculation—takes much time. Hence, fast calculation methods are required. Although parallel processing is a hopeful method, there have been difficulties in the parallel solution of linear equations which appear in power-flow calculations by the Newton-Raphson method. This paper aims at the fast calculation of the power-flow problem by means of parallel processing. In order to improve the suitability to the parallel solution of the differential equation in transients calculation, we assume the use of a direct-mapping parallel processing machine to map directly the network of a power system onto a network of processors. Under this assumption, we propose a new parallel-processing-oriented method in which the linear equation is solved by linear iterations between nodes with Aitken acceleration. We simulate the method on three model power systems and compare this Parallel Iterative Method (PIN) with a Parallel Direct Method (PDM) which uses the banded matrix according to the number of operations required. As a result, we can expect that PIM may solve linear equations faster than PDM with m processors, although the PIM might be inferior to the PDM with m × m processors, where m denotes the half-band width of the banded matrix.     

Kinetic study of the hydrolysis of isocyanic acid in the gas phase

The hydrolysis of isocyanic acid in the gaseous phase has been investigated at temperatures between 553 and 613 K by mass spectrometry and evaluated to obtain the corresponding kinetic data. The reaction order and reaction constant have been determined. Finally, the influence of water on the catalysed formation of melamine from isocyanic acid under the operating conditions employed has been investigated in order to determine whether there is a need to try the process gas.     

对洪水分级的浅见

洪水的等级划分应考虑流量、水位、防洪能力及灾害等因素,综合这些因素把洪水分成5个等级。1、2级洪水,洪水流量小,水位低,基本无灾;3级洪水,洪水流量较大或水位较高,有一定灾害;4级洪水,为大洪水或高水位,有较大灾害;5级洪水,为特大洪水或高水位,灾情严重。     

变结构变参数设计方法及其在机械CAD中的应用

提出了一种新颖的机械结构设计思想－变结构变参数设计方法，并结合实例，阐述了变结构变参数设计的概念、原则、实施措施和意义。由此对Ｉ－ｄｅａｓ软件包进行了二次开发，编制了发动机曲轴专用ＣＡＤ软件程序，并用某型号发动机曲轴进行了验证。