Volume 13,Issue 1,1990 Table of Contents

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  • 1  THE NEW METHOD-QL SYSTEM FOR MEASURING DYNAMIC ACCURACY OF THE DRIVETRAIN
    Qin Shuren Wang Jiachen Hu Xinyi Jiang Guongcheng
    1990, 13(1):1-12.
    [Abstract](552) [HTML](0) [PDF 583.17 K](1027)
    Abstract:
    The paper introduces a new method-QL system suggested for the first time by the author for measuring dynamic accuracy of gear cutting machine drivetrain. The system has many uses. It suits not only the measurement of mid-size machine tool but also the measurement of very slow speed, large ratio, large-size machine drivetrain
    2  COMPUTER ALDED DESIGN OF FORMING CUTTER FOR REVISING INVOLUTE HELICAL
    Xiao Dichen Liang Xichang
    1990, 13(1):13-22.
    [Abstract](780) [HTML](0) [PDF 430.97 K](1734)
    Abstract:
    In this paper, a calculation method of forming cutter contour of involute helical with arbitrary easement is presented, the segmantal arcs of the best uniform approximation and tolerance to fit smoothly the cutter contour points are used the profile on the cross section of the helical is calculated and the design of the cutter is examined. The method can be used to design precision forming cutter of involute helical with the arbitrary easement. It is valuable in engineering application.
    3  A NEW PWM METHOD-AVERAGE VALUE PWM
    Wang XueqinTangYaolin
    1990, 13(1):23-24.
    [Abstract](806) [HTML](0) [PDF 111.03 K](190)
    Abstract:
    In this paper, a new PWM method-average value PWM is presented. This method has been compared with other PWM methods and realized by using a micro - processor-controlled GTR inverter. Some experimental results and discussions for them have been given.
    4  INFLUENCE OF THE GEOMTRIC PARAMETERS OF LOW FINNED TUBE ON BOLHING HEAT TRANSFER AND OPTIMIZATION OF THE PARAMETERS
    Dong Liang Zhang Hongji Chen Junguo
    1990, 13(1):35-41.
    [Abstract](669) [HTML](0) [PDF 340.08 K](213)
    Abstract:
    On the basis of the mechanism of the boiling heat transfer on low finned tube, the influence of the geometric parameters of low finned tube on boiling heat transfer is synthetically analyzed and relevant criteria which affect the optimal structure of low finned tube is deduced in this paper. The boiling heat transfer experiment on low finned tube is conducted. Distilled water and R-113 are used as test fluids The experiment is performed at local atmospheric pressure. Synthesizing a large amount of experimental data, the semiempirical equations for the optimal geometric parameters of lowfinned tube are established
    5  DIGITAL POWER SYSTEM STABILIZER ( DPSS )
    Chen Ganping Xu Guoyu Qin Yihong
    1990, 13(1):43-48.
    [Abstract](743) [HTML](0) [PDF 318.17 K](204)
    Abstract:
    A digital power system stabilizer ( DPSS ) and its design method are presented in this paper. The mathematical model of a single machine infinite bus power system is obtained using off-line parameter identifications, and on the base of the identified model the control system is synthesized by generalized minimum variance control principles. Through feedback combination of several signals this control system has double functions of damping low frequency oscillation and automatic voltage regulating. In order to avoid static errors the very effective way is to combine discrete generalized minimum variance control with continuous integral control. Besides the proposed control strategy is very simple in structures and very easy to realize. Simulation results under several cases have shown the correctness and effectiveness of the proposed control strategy.
    6  AN IMPROVED METHOD OF CALCULATION FOE UNSYMMETRICAL OPEN CONDUCTOR STATES IN THREE-PHASE POWER SYSTEMS
    Mi Linshu
    1990, 13(1):49-55.
    [Abstract](643) [HTML](0) [PDF 254.37 K](174)
    Abstract:
    In this paper, the superposition and compensation theorems are employed to calculate the electric values under the unsymmetrical open conductor states in the three-phase power systems without modifying the bus admittance or the impedance matrices of the original networks. In cotrast with conventional algorithms, the method proposed here is highly accurate, fast, convenient and flexible. It can be applied to the unsymmetrical open conductor calculations which offered in power systems for its design and operation, to determine the settings of relay and automatic deyices, as well as accident analysis.
    7  STATE VARIABLE METHOD FOR DYNAMIC SIMULATION OF HVDC SYSTEMS
    Zhang Wei Ren Zhen Qin Yihong Liao Qing
    1990, 13(1):56-62.
    [Abstract](571) [HTML](0) [PDF 391.87 K](222)
    Abstract:
    A flexible mathematical model used for dynamic simulation studies of HVDC systems which is based on the stale variable method is presented, and the correspongding computer program has been implemented. Generality, easy to use, and suitable to run on microcomputers are the main features of the model and the computer program. Therefore the model is easy to be extended for application. An example is given in the paper to verily the coneclness of the model and the program.
    8  TRANSIENT STABILITY ANALYSIS OF PARALLEL AC/DC SYSTEMS
    Ren Zhen Ran Li Zhang Wei Lan Qinghua Li Zhengran
    1990, 13(1):63-69.
    [Abstract](646) [HTML](0) [PDF 373.45 K](179)
    Abstract:
    In this paper the particular problems in transient stability study of parallel ac/dc systems are analyzed, a mathematical model together with the relevent algorithms for transient stability evaluation is proposed, and an illustrative example is given to show the effects of dc adjustment and the correctness of the model and algorithms.
    9  THE ANISOTROPY DISCONTINUITY MODEL DUO TO THE STRIKE OF THE TAGGED DISCONTINUITIES
    Li Tonglin Wang Yanhui
    1990, 13(1):70-77.
    [Abstract](995) [HTML](0) [PDF 407.83 K](187)
    Abstract:
    In this paper, on the base of the original shapes of discontinuities in engineering gedogy, we mainly discuss the ralations among the shape of discontinuity, the restraining effects of discontinuity deformations (including the normal deformation and the shear deformation ) and the crustal stress. Then we put forword the concept of the pseudo-dilatancy ungle which can indicate the motion direction, set up the anisotropic discontinuity model, and give some important results and formula for illustrating truly the discontinuities in rock engineering.
    10  THE "EXPERIMENTAL STUDY OF THE RELATION BETWEEN THE MAGROMOLECIJLAR STRUCTURE OF COAL AND ITS RANK
    Zhang Daijun Xian Xuefu Tan Xueshu
    1990, 13(1):78-84.
    [Abstract](799) [HTML](0) [PDF 388.60 K](368)
    Abstract:
    In this paper, by Using Traube's Law, we presented a method with which the macromolecular structure of coal can be studied through the relation between the true density of coal and its chemical constitution Then we researched the law of the variation of the macromolecular struclure of coal with its. rank. At the same time, we discuss the rank of coal which is classified in the constitution and macromolecular structure of coal
    11  THE PERFORMANCE ANALYSIS FOR THE HYDRAULIC SERVO-SYSTEM OF HAULAGE PARTY FOR SGW-150 SHEARER WITH CONSTANT POWER SPEED GOVERING
    Yin Zhengxi Yuan Dengfang
    1990, 13(1):85-95.
    [Abstract](538) [HTML](0) [PDF 369.43 K](134)
    Abstract:
    The mechanization of mining thinnest coal seam is a key program in the 7th five-year plan in Sichaan province, It is sponsored by The Scientific and Technieal Commission of Sichuan province. In this paper, the dynamic performance for the hydraulie servo-system of haulage party for SGW-150 shearer with coustant-power speed governing is analysed. It shows that the system designed by us is stability and reasonable for SGW-150 shearer.
    12  ON STUDY DIGGED FIELD MOVEMENT''''S LAW BY EXPERIMENTAL METHOD OF LASER HOLOGRAPHIC MOIRE INTERFERMETRY
    Wang Baichu Hu Guohua Chao Zhen Xu Guangming Cheng Yanssong
    1990, 13(1):96-101.
    [Abstract](654) [HTML](0) [PDF 329.49 K](172)
    Abstract:
    The high-precision displacement measuring technology of optic-measuring mechanics is, for the first time,successfully applied on the similar model of the model land-layer with a new-type variable modulus of elasticity. The angle of movement and the distributed displacement of upper and lower rock-layers are measured. The technology is a combination of laser's technology and the modern chemical sticker-it is called the sticking moire interferometry. Compared with the measured values, the result is very satisfactory.
    13  PRELIMINARY RESEARCH OF PHOTOELASTIC ISODYNES EXPERIMENTAL TECHNIQUES
    Qian Zhenming Wan Yalan Wan Fu
    1990, 13(1):102-109.
    [Abstract](630) [HTML](0) [PDF 400.04 K](1008)
    Abstract:
    The photoelastic isodyne experimental apparatus investigated by authors is presented. The design of the integrating prism ard the relative experimental techniques are discussed,Using this apparatus the two fundamental experiments on the stress analysis of the circular disc loaded along vetical diameter and the determination of the stress intensity factor for the side crack of the extension-loaded plate are completed.
    14  DYNAMIC ANALYSIS OF SPINDLE
    Yang Yudin Liu Dejun
    1990, 13(1):110-118.
    [Abstract](496) [HTML](0) [PDF 309.59 K](992)
    Abstract:
    In this paper, taking a D1201 spindle as an example, we discuss the dynamic analysis of spindle by using the theory of the complex model, we also analyse the factors which effect the dynamic characterics of spindle and give results which arc reference value to improving the structure of spindle,
    15  DATA COMPRESSION WITH HASH CODES
    Tan Qiangmin
    1990, 13(1):119-126.
    [Abstract](1665) [HTML](0) [PDF 445.91 K](1269)
    Abstract:
    In many database applications, data have to be compressed before they can be stored. Data compression techniques with less overhead and better space saving are expected. This paper gives a data compression technique by which the size of a file may be reduced through substituting codes for its field values. The codes are the corresponding locations of the values in the hash table that is comprised of all the values of the field.The compression is effective for many applications, and the cost of the coding/decoding is equal to that of one access to the hash table. The implementation of the technique as a compression tool in DBMS for date storage and the algorithms of the coding/decoding are discussed.

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