1990 Vol.12 No.6, Published: 19 November 1990
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Wang Yueqing
ANALYSIS OF ELECTROMAGNETIC CHARACTERISTICS OF 3-D MEDIA RADOME BY COMPLEX ASTIGMATIC WAVE THEORY
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1990 Vol. 12 (6): 561-568
[Abstract]
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1459 )
[PDF 1321KB]
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694
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DOI:
The complex astigmatic wave theory is used to analyse the electromagnetic characteristics of 3-D radome. A number of calculations for the ellipsoidal sandwich radome are performed, and the stereoscopic graphics are constructed. Comparing with the experimental results, it is shown that this method can be used to simplify the optimization designs for some kinds of 3-D radomes.
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Zhang Jun; Huang Guanglian; Zhang Jian
TIME-DOMAIN DYADIC GREEN s FUNCTION AND THE CHARACTERISTICS IN TIME-DOMAIN FOR AN IDEAL CONDUCTING WEDG
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1990 Vol. 12 (6): 569-574
[Abstract]
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1809 )
[PDF 855KB]
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536
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DOI:
Based on Ohm-Rayleigh method and Laplace transform, the time-domain dyadic Green s functions for a ideal conducting wedge are obtained. The Characteristics of the wedge in time-domain are systematically analysed. Some conclusions are given, and C. T. Tai s theory (1973) is complemented. These studies are provided a further reference for time-domain analysis of an ideal conducting wedge.
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Hong Wei
ANALYSIS OF HYBRID MODES OF WAVEGUIDE BY A MODIFIED BOUNDARY ELEMENT METHOD
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1990 Vol. 12 (6): 575-583
[Abstract]
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1506 )
[PDF 1056KB]
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497
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DOI:
A modified boundary element method for analysing hybrid modes of waveguide is presented. The coupled boundary integral equations and their reduced forms are deduced for hybrid mode problems, and these equations are discreted into a system of linear algebraic equations by moment method. Finally the dispersion characteristics of rectangular waveguide filled with two kinds of dielectrics are calculated and the numerical results are in good agreement with that obtained by transverse resonating method.
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Mao Yimin
SPLIT RADIX AIGORITHMS FOR LENGTH pm DHT s
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1990 Vol. 12 (6): 584-592
[Abstract]
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1496 )
[PDF 1146KB]
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478
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DOI:
The split radix approach is generalized to length pm Discrete Hardy Transform (DHT). It is shown that the radix p/p2 algorithm is superior to the radix p2 and radix p algorithms in number of real multiplications. As an example, a radix 3/9 algorithm is developed for length-3m DHT, and the signal flowgraph is given.
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Li Wenzhe; Lin Feng; Chang Weiguo; Wang Dejun
PARASITIC TOLERANT DIFFERENTIAL SC TRANSCONDUCTANCE USING UNITY GAIN BUFFERS
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1990 Vol. 12 (6): 600-606
[Abstract]
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1899 )
[PDF 1119KB]
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701
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DOI:
The unity gain buffer will be good for designing high frequency SCF if its resistive effect can be eliminated and then the overall parasitic sensitivity will be greatly lowered. Based on this concept, a new parasitic tolerant SC differential transconductance element (DTE) is proposed. SC floating inductor and integrator applicable to high frequency are formed by using the DTE. The computer simulation and experiment on a 3-order elliptic LP filter show the correctness of the concept.
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Zhang Junling①;Zhu Xuelong②; Zhu Zhengzhong②
RECOGNIZATION OF MODULATION SYSTEMS IN COMMUNICATION
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1990 Vol. 12 (6): 607-613
[Abstract]
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1592 )
[PDF 1191KB]
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765
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DOI:
Recognization of modulation systems is an important problem in the modern electronic reconnaissance. A general method for solving this problem is suggested. From a segment of a captured signal, the modulation system can be determined, and its parameters can be extracted by using this method. The theoretical basis, algorithms and test results of this method are described. It is proved that the method is very effective in practical situation.
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Liu Haoning; Zhu Xieqing
NUMERICAL COMPUTATION OF PROCESSING ERROR EFFECT OF LENSES IN ELECTRON BEAM FOCUSING AND DEFLECTION SYSTEMS
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1990 Vol. 12 (6): 614-627
[Abstract]
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3069 )
[PDF 2075KB]
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794
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The numerical computation of processing error effect of lenses (i.e., the ellipticity and tilt of electrodes/pole-pieces in electron beam focusing and deflection systems) and its evaluation are discussed. First, the computation of the potential distributions of lenses with elliptical holes of tilt surfaces on electrodes/pole-pieces using the finite element method is described. Then, the formulae for evaluating the changes of the optical properties caused by the processing errors (i.e., the additional image shifting and additional aberrations) are derived. Finally, some illustrative examples of processing error effect evaluated by the computer programs developed are shown as the spot-diagrams.
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Su Xuchun; Fang Houmin
INVESTIGATION OF THE SURFACE CHARACTERISTICS OF A ALUMINATE DISPENSER CATHODE WITH Y2O3
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1990 Vol. 12 (6): 628-635
[Abstract]
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1597 )
[PDF 1620KB]
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648
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A Aluminate dispenser cathode with Y2O3 have been investigated by using modern surface analysis techniques (AES, XPS, SEM and THEM). The Surface topography, Surface chemistry and emission properties of the cathodes activated in situ have been obtained. The experimental results and activation mechanism are also discussed.
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Mao Peifa; Jiang Laixi
THE DESIGN OF THE HIGH SPEED AND HIGH PRECISION LATCHING VOLTAGE COMPARATOR ZJ 03
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1990 Vol. 12 (6): 636-640
[Abstract]
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1789 )
[PDF 1009KB]
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1133
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The design of a new type of sampling latching voltage comparator ZJ03 is described. The common voltage comparators consist of multistage DC amplifier. It is difficult to realize high speed and high precision. The voltage comparator ZJ03 contains a controlled positive feedback amplifier. Therefore, it is capable of realizing high speed and high precision. For improving the performance and yield, the tolerance extension, design centering and potential adapting are used for the design of the valtage comparator ZJ03.
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Hou Zili; Peng Lanfang
PORT RATIO BRANCH LOCATION OF SHORT FAULT FOR TREE TYPE POWER NETWORK
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1990 Vol. 12 (6): 641-645
[Abstract]
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1793 )
[PDF 770KB]
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568
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The port ratio faulty branch location method presented here is aimed at the peculiarity of 10 kV power network in China. By using this method, on line automatic diagnosis of the same place short fault is solved. This method has some features: the model s simplicity; operational convenience and high location accuracy.
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Feng Wenlan; Ruan Yingzheng
ANALYSIS OF TARGET RCS BY COMPLEX RAY EXPANSION
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1990 Vol. 12 (6): 646-649
[Abstract]
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1496 )
[PDF 731KB]
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625
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Based on the complex ray method and source expansion with a set of Gaussian beams, a new method for analysis and calculation of radar cross-section (RCS) of a complex target is presented. This method can be used for arbitrary shaped object, because complex ray analysis is not limited by the shape of object. A hollow rectangular pipe as a model of an air intake is investigated. The effectivenejs of this method can be proved from the comparison of calculated and measured results.
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Fan Rongtuan
PREPARATION OF CROSS-SECTIONAL SPECIMEN OF SEMICONDUCTOR FOR TEM AND ANALYTICRESULTS
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1990 Vol. 12 (6): 656-659
[Abstract]
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2514 )
[PDF 840KB]
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1109
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The technique for preparing cross-sectional specimen of semiconductor for TEM is shown. In such specimens prepared with the technique, an unexpected periodic compositional modulation in the fine low-dimensional structure named "Fine Low Dimensional Modulated Fringes" of GaAs/AlGaAs multilayers grown by MBE are observed. Some new patterns of dislocations, defects and microtwins etc. in GaAs/Si grown by both MBE and MOCVD are remarked. The technology can be adapted to the study of other systems of semiconductor materials also.
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Yang Deqing; Song Hongjiang; Wang Zhi; Chen Ergang
A SEMIEMPIRICAL FORMULA FOR THE SHAPE FACTOR OF EMISSION TIP IN GENERAL FIELDE MISSION SYSTEM
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1990 Vol. 12 (6): 660-665
[Abstract]
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2305 )
[PDF 1011KB]
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633
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A new formula (β≈0.2/[(r0+h)ln (2h/r0)]) which is used to determine the shape factor of field emission tip is reported. By using of this formula, the calculation of β with the tip shape of half spheroid, rotational ellipsoid, rotational paraboloid and rotational hyperboloid have been made and compared with the calculated value of β by D. Selidovkin, W. Swanson and P. Dyke and numerical method. It is shown that the value of β calculated by using of the new formula is consistent with the result of calculation by computer and is more precise than that calculated by using of other method.
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