RESEARCN OF MODEL OF AUTOMATIC CHECWEIGHER

Generally,a second order spring-damper system is used to represent the model ofweighing sensor in checkweigher. It only represents one part of checkweigher.In this paper,accord-ing to the relationships of individual parts of checkweigher and main disturbance source,a model isproposed for whole checkweigher.It is proved by simulatlon that this model is in a good approxima-tion.     

ON THE PROBLEM OF SWITCHING CONDITIONS FOR A KIND OF MINIMUM-TIME CONTROL SYSTEMS

The paper provides a detailed study of switching conditions of minimum-time control systems based on application in engineering. By analysis in theory and experiment, the authors deduce a set of switching conditions with state and control variabes inequality constraints, the variations of system parameters and the time-delay of computer in real time control. As an example, a DC motor speed control system is considered. By digital simulation and physical experiments,these conditions proved to be correct. The method in this paper is also suitable for other control systems using compound control algorithm.     

环流熏蒸系统环流方向改进试验

将单向环流熏蒸系统改进为双向环流熏蒸系统进行试验,以更好地满足浅圆仓和立筒仓环流熏蒸的要求。通过试验发现,双向环流熏蒸系统较单向熏蒸系统有以下优势:(1)达到仓内磷化氢气体浓度均匀的环流时间更短,且均匀效果更好;(2)可灵活控制仓内表层磷化氢气体浓度,使表层浓度高于有效浓度的时间更长;(3)由于环流时间缩短,所以环流所引发的仓内温湿度波动情况有所缓解。     

INVESTIGATION OF DEVELOPMENT SYSTEM OF 1802 MICROCOMPUTER

Based on general concepts of microcomputer developmentsystem,the design concept and main characteristics of 1802 microcomputerdevelopment system are introduced in this paper.This system is ratio-nally designed,powerful in function and very useful for further develo-pment and application of 1802 host computer in communication.     

OPTIMIZATION DESIGN OF ADVANCED CORRECTION OF THE CONTROL SYSTEM BY A PASSIVE NETWORK

Optimization design of correction of the control systemby a passive network is studied in this paper.The design method guan-rantees collocation of a closed loop pole in a desired position,but alsominimizes the gain of the system amplifier,thus making the technicalrealization of the system easier.The design method is proved in thepaper.     

A SYSTBM OF SAVING VENTILATION ENERGY POR MULTI_STORIED HEALTNY BUILDINGS

A sving energy system can get natural ventilation in the storied healthy build-ings with air condition or heating. The principal component of this system is an efficient heat ex-changer made of a set of heat pipes. This system can be operated between two sides of one floor slabto change the energy carried both by the hot air flow and the cold air flow, This svstem can make aspossibly keeping indoor air fresh with a little energy air loss only. It is possible for using this systemto cure a sick building into a healthy building. This system can be put dperation between both thepipes of waste air flow and fresh air flow for an integrated air conditional svstem with fresh air.     

A NEW APPROACH OF OPTIMIZATION

In this paper, a necessary optimality condition of problems with equality constraints is investigated by the implicit function theorem in n-dimensional Euclidean space. A new approach solving these problems is obtained. The number of dimensions of corresponding system of equations is less than the classic Lagrangian multiplier method.     

A NEW METHOD FOR DESIGN OF PSS PARAMETERS

The eigenvalue sensitivity methods is very useful not only in analysis of electric power system stability but also in design of the controllers. In this paper a new optimal method is proposed to design the parameters of PSS. Using this method the PSS is designed for a single machine-infinite bus system, and the results of digital simulation show that this method is very effective and useful.     

ON THE STUDY OF THE INFLUENCE OF MASS DISTRIBUTION ON DYNAMIC CHARACTERISTICS OF A SPINDLE SYSTEM WITH MODALITY ANALYSIS METHOD

The modality analysis method is employed in this paper to study the influence of mass distribution on dynamic characteristics of a spindle system. It is found that there exist obvious difference between the influences of different mass distribution on the natural frequencies . and modality flexbilities of various order-mode. It is shown that the proportion of modality flexbility in the astatic flexbility can be equilibrated by means of adjusting correctly the mass distribution of the spindle system so that the cutting stability is improved as well. Experiment results are quoted to confirm, in a certain degree, the conclusion above.     

磷化氢环流熏蒸技术应用中需注意的几个问题

本文从仓房的气密性、用药量浓度和密闭时间与杀虫效果的关系、磷化氢环流熏蒸中可采用的几种方式、熏蒸效果的检查与评价等几个方面阐述了磷化氢环流熏蒸中应注意的若干问题，并对几种不宜进行整仓环流熏蒸的情况进行了说明。     

DIRECT METHOD OF PROBABILISTIC PRODUCTION SIMULATION BASED ON MIXTURES OF NORMAL DISTRIBUTIONS

This paper describes a new probabilistic production simulation method based on mixtures of normal distributions. This method does not require to modify the original load,and the relevant formulae are derived directly from the mixture of normal distributions of load and the mixture of normal distributions of system power. Numerical results indicate that this method is accurate and rapid in comparison with the conventional and the cumulant methods.     

基于混合蚁群算法的粮食物流中心选址优化

粮食物流中心是粮食物流系统的枢纽,粮食物流中心地址的确定是粮食物流系统分析的核心内容.根据粮食物流中心选址问题的特点和要求,在运输成本最低的基础上,构造了选址问题的数学模型,并且针对该模型引入一种混合蚁群算法,将遗传算法与蚂蚁聚类算法融合,采用遗传算法生成信息素分布,利用蚂蚁聚类算法求精确解.从而有效地避免算法的早熟现象,可防止其很快收敛到局部最优解,实例求解表明,该算法可以有效、快速地求得粮食物流中心选址问题的全局最优解.     

ANALYSIS OF THE ZERO SOLUTION STABILITY OF LAMINAR BOUNDARY LAYER EQUATION

Two-dimensional incompressible laminar boundary layer equation can be changed into Blasius equation by means of similarity transformation. In this paper, Blasius equation 2f" '+ff"=0 is transferred into a nonlinear and autonomous system of second order by variable transforming. Taking the advantage of its approximation to linear system, the stability near zero solution can be discussed.     

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.     

THE APPLICASION OF SUPERVISOR CALL(SVC) FUNCTION IN DEVELOPING OF RMS SYSTEM

RMS system is a running management system self designed and developed for M304s computer system. Supervisor call (SVC) is one kind of method of communication between user and system in designing of operating system. This article introduces you the way how to resolve the problem in RMS design by using supervisor call function, with brief introduction of system design.     

ANALYSIS OF THF INFLUENCE OF CHANNEL ON SIGNAL TRANASMISSION IN THE WIRED MWD SYSTEM

An analysis of the influence of channel on signal transmission in the wired measurcments-while-drilling ( MWD ) system is made. The cases of reflection and refraction to the signal at connecting points of wires are analysed. The transmitting channel must consist of many sections of wires in this measuring system. A few noteworthy practical problems arc put forward when designing this message-transmitting channel.     

ENERGY-SAVING AND OPTIMAL HIERARCHICAL CONTROL OF WATER PLANT

In this paper, on condition that the production processes in water plant are related with each other, a new coordinative algorithm is presented, using a hierarchical control structure and taking the equivalent efficiency of the pump station as coordinative variable. In this way, the problem of optimal control of the complex delay system is solved. Simulation shows that great energy-saving efficiency may be obtained by the above method.     

低功耗粮情测控物联网模型研究

以储粮粮情测控为研究背景,以降低粮情测控系统功耗为目标,提出了一种低成本、低功耗、可扩展的弹性粮情测控物联网模型。粮情测控物联网模型包括三层结构:感知层、传输层和汇聚层。感知层支持多参数粮情数据感知;传输层多跳传输粮情数据;汇聚层兼容GPRS、WIFI、WLAN、3G、Enthernet等通信方式,系统结构灵活,扩展性强。实验验证,该模型相较于传统的WSN至少可以延长粮情测控系统的寿命,粮情感知节点在不更换电源情况下可以工作3~5年。     

THE STUDY OF SINGLE CHIP COMPUTER BASED SYMMETRICAL COMPONENT DISTANCE PROTECTION

In this paper, a new microcomputer distance protection scheme with high property-cost ratio has been approached. The paper presents the performance equations based on the symmetrical components of current and voltage, proposes a new (1,a) coordinate plane and derives a Fourier symmetrical component algorithem with high accuracy and less calculation amount on the (1,a) plane. The protection program is debugged on the developing system of single chip computer. The digital imitation tests indicate that the proposed relaying system is satisfactory.