Volume 11,Issue 6,1988 Table of Contents

  • Display Type:
  • Text List
  • Abstract List
  • 1  A FAST ALGORITHM FOR DIGITAL SIMULATTON OF HVDC SYSTEMS
    Zhang Wei Ren Zhen
    1988, 11(6).
    [Abstract](667) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    After considering the features of the differential equations which have described the dynamic behaviours of HVDC systems, a fast algori -thm is presented for these equations. Compared with the fourth Runge-Kutta Method,this method has less amount of calculation with the same precision, numerical stability and other properties. Therefore, the use of the method has greatly increased the speed of the digital simulation of HVDC systems.In this paper an example of calculation is given, and the results obtained hv using this example are compared with the results obtained by calculating with the fourth Runge-Kutta Method. The speed of simulation by using this method is about 1.8 timss as fast as that by using the fourth Runge-Kutta Method.
    2  THE COMPENSATION OF THE OP AMP FINITE GAIN EFFECTS IN SWITCHED CAPACITOR FILTER
    Zeng Xiaoping Zhou Baowei
    1988, 11(6).
    [Abstract](585) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    本文提出了运放增益为有限值时的SC电导和SC阻抗模型,用它们分析了运放有限增益对双二阶开关电容滤波器(SCF)性能的影响。提出了降低负反馈以补偿这些影响的原理及实现方法。该方法简明直观,不需要增加运放,可达到完全补偿,且适用于其它开关电容网络(SCN)的有限增益补偿。
    3  A NEW DISCONTINUOUS CURRENT MODEL FOR SCR DC MOTOR SPEED CONTROL SYSTEM AND CURRENT ADAPTIVE CONTROL
    Luo Xian-zhi Meng Xiao-feng
    1988, 11(6).
    [Abstract](536) [HTML](0) [PDF 0.00 Byte](2)
    Abstract:
    The paper presents a new approximative model suitable to discontinuous current and continuons current in the three-phase controlled bridge rectifier DC motor control system. This model offers a new approach for discontinuous current adaptive control.As an example of application of the model, digital simulation results of discontinuous current adaptive control in a double-closed-loop control system are presented.
    4  A RESEARCH INTO THE Mn-Si-Cr AS-ROLLED DUAL-PHASE STEEL TREATED WITH TRACE B AND Ga
    He Zefu Liu Tianmo
    1988, 11(6).
    [Abstract](539) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    In this paper, the alloying of the as-rolled dual-phase steel treated with trace B and Ga is discussed. On the basis of Mn-Si-Cr alloy system, a new type as-rolled dual-phase steel containing trace B and Ga is developed, with a lower production cost equally high technological property, and similar CCT curve compared with that of the Cr-Mo system as-rolled dual-phase steel.
    5  A STUDY OF IMPULSIVE HEATING OF METAL
    Zhao Yufen Qian Guotang Zhu Qionghua Liu Jianmin
    1988, 11(6).
    [Abstract](491) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    金属冲击加热是对流快速加热的一种新型加热工艺,也是金属加热的一项节能新技术。它是用高温高速气流直接冲击金属表面的快速对流加热方法来完成金属锻前或轧前的加热,金属加热温度均匀、加热速度快、加热时间短,可以大大降低燃耗。本文由金属冲击加热数学模型,用计算机解出了获得最佳加热炉温和断面温差最小的加热时间时换热系数范围为:300~500KKal/m~2·h·℃
    6  STUDY OF DETERMINING THE DEGREE OF GRAPHITIZING OF COKE WITH X-RAY DIFFRACTION METHOD
    Zou Deyu Zhang Binghuai Liao Bogang Chen Changguo Zhang Qao
    1988, 11(6).
    [Abstract](636) [HTML](0) [PDF 0.00 Byte](2)
    Abstract:
    In the paper, the process of determining the degree of graphiti-zing of metallurgy coke with X-ray diffraction method was discussed. The extrapolation was used in order to obtain the interplanar distance. of (002) crystaloface of metallurgy coke. The finding showed that the dmax. wasn't 3.44A, butO4.31A. A rational formula which could be used to characterize the degree of gra-phitizing of metallurgy coke was found.
    7  A GROUP-DIVIDING SYNTHEIS METHOD FOR SIX-BAR PLANER MECHANISM''''DRIVEN BY PNEUMATIC/HYDRATIC DRIVING SYSTEM
    Yen Weiming Tang Weibo
    1988, 11(6).
    [Abstract](497) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    The paper employs the combination of the group-dividing synthesis and optimum method to establish the synthesis method used in which the type stepheson six-bar planer mechanism is used as the function generator which is driven by a pneumatic/hydraulic cylinder. The linear superposition technique is used in the whole solving process and the number of the design positions is not limited by the unknown parameters.
    8  INTRODUCTION TO A NEW AUTOPROGRAMMING SYSTEM FOR NC LATHE
    Ma Jun Chen Qinashen
    1988, 11(6).
    [Abstract](587) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    This paper deals with the BCH autoprogramming system based on the principle of "representing shap with numbers", With this system, the organization of turning process can be accomplished by inputting only some codes and a few characteristic parameters, and the NC block instructions to control the NC lathe via control unit can be output in turn so that it is possible to write a part program at the shop floor which is benifitian for developing a new programming method to be used in a multistage computer manage system with communicating interface.
    9  LABORATORY INVESTIGATION OF ESSENTIAL CHARACTERISTICS PARAMETERS FOR THE INDUCED-NOZZLE DEVICE
    Zhang Fenghua Liao Zhenfang
    1988, 11(6).
    [Abstract](416) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    The standoff of a submerged jet is smaller than a non-submerged jet in general. In order to increase the standoff of a submerged jet, the induced-nozzle device is presented with its inducing mechanism analysed in this paper. Under the various inducing medium, the effect of the ratio d2/d1 upon the device's properties is measured. Some reasonable parameters are given. When d2/d1=2.0, approximate straight region of the curve of the jet center line stagnation pressure varying with the standoff is L/d1= l0~12 for inducing air. The induced-nozzle device is compared with the conventional nozzle for shotting some samples. Several applied possibilities of the device are discussed.
    10  THE STUDY OF ROCK FRACTURE
    Li He Yin Guangzhi Zhang Wenwei
    1988, 11(6).
    [Abstract](380) [HTML](0) [PDF 0.00 Byte](2)
    Abstract:
    This paper is about the fracture tests for rocks performed under the stress of compression and shear. The characteristics of cornpre-ssive and shear fracture for rocks are described. The compress shear fracuure criteria of rocks are obtained.
    11  EFFECTS OF NON-LINEAR DISCONTINUITY ON STRESSES AND DISPLACEMENTS IN ROCK AROUND TUNNEL
    Li Tonglin Zhu Hehua
    1988, 11(6).
    [Abstract](374) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    本文采用边界元法详细分析了非线性不连续面几个主要特性参数:初始法向刚度K_(ni)、初始剪切刚度[K_(Si)=K_(jrω)(σ_n/P_a)~(nj)]和不连续面最大闭合量V_m对巷道围岩应力,位移分布的影响。分析表明,随着上述参数的变化而使得不连续面变软时,应力、位移变化相当显著,由此而得出一些有价值的结论。
    12  DUST DEPOSITION FROM TURBULENT GAS STREAMS IN MINE AIRWAYS
    You Kui Wu Zeyuan
    1988, 11(6).
    [Abstract](604) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    In this paper, dust deposition from turbulent gas streams in mine airways is studied both theroetically and experimentally. Base on the practical situation of mine airways, we only considered the effects of Brc-wnian, turbuleut diffusion and gravitation and suggested a mathematical model of dust deposition from turbulent gas streams in mine airways. The comparison of the experimental result is consistent with the model suggested in this paper.
    13  BICHARACTERISTICAL THEORY AND ITS APPLICATION FOR UNSTEADY COMPRESSIBLE AND INVISCID FLOW WITH SYMMETRIC AXIS
    Chen Jingqiu
    1988, 11(6).
    [Abstract](456) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    The Bicharacteristics-Method for unsteady, compressible and inviscid flow has been developed in four . dimensional time-space. A new shock-tracing has been presented. A successful numerical solution for reflexion and focusing of a shock has been made.
    14  THE APPLICABILITY OF OVERLAPPING DECOMPOSITION DECENTRALIZED CONTROL
    Chen Ganping Qin Yihong
    1988, 11(6).
    [Abstract](445) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    The overlapping decomposition decentralized control is a kind of static feedback control system. Using overlapping information sets among subsystems, the reliability of the control system is improved. On the other hand the overlapping decomposition decentralized control systom isn't suitable for all systems waiting control. As for some systems, using overlapping decomposition decentralized control doesn't reach the desired control effect. This paper has discussed the applicability of the overlapping decomposition decentralized control offers the necessary conditions for applying this control technique, and provides theoretical basis for the wide applications of the overlapping decomposition decentralized control systems.
    15  OPTIMAL ACTIVE POWER ADJUSTMEMT OF LARGE HYBRID AC/DC SYSTEMS AFTER OUTAGE CONTINGENCIES WITH THE APPLICATION IN RELIABILITY EVALUATION
    Ran Li Ren Zhen Jiang Zejia
    1988, 11(6).
    [Abstract](562) [HTML](0) [PDF 0.00 Byte](1)
    Abstract:
    An optimal active power adjustment model is deve in this paper for hybrid AC/DC systems after outage contingencies. The objective of the model is to minimize the rejection of load when some elements are out of service, with adjustment strategy approaching practical system operation. A large number of outage contingencies are simulated when the Monte-Carlo Method is emyloyed to evaluate the system reliability, requiring fast calculation of each simulation. The model and computer method proposed in this paper satisfy such a requirment because of the application of concentric relaxation, recursive branch constraint treatment in linear programming and a direct method for B-1 matrix modification. This paper is concerned with the simplified steady state conditions of the system based on DC load-flow, which implies the reliability indices calculated are the measures about static loss of load. The results for a 14-bus hybrid AC/DC system are given.
    16  RESEARCH ON SURFACE QUALITY OF BELT GRINDIIIG
    Zhang Jianjun Xu Faren Guo Wenliang
    1988, 11(6).
    [Abstract](553) [HTML](0) [PDF 0.00 Byte](2)
    Abstract:
    Through a large number of tests of grinding the cycloidal flanks with abrasive belt, the surface roughness and residual stress exist in the complex curved parts resulting from large-curvature belt-grinding are discussed. The effect of the technical parameters on surface quality is analyzed and the empiric formula is given. This is enable to provide the grinding process with correct selecting of technical parameters.

    Current Issue


    Volume , No.

    Table of Contents

    Archive

    Volume

    Issue

    Most Read

    Most Cited

    Most Downloaded