最新刊期
卷 ， 期 6 ， 1993
- 摘要：The present paper describes a multigrid method which is used to calculate the electrostatic potential distributions for the rotational symmetrical electron-optical systems that have internal electrodes and different boundaries.It appears that the computational efficiency and accuracy of the multigrid method are better than finite difference method.This method can be applied to design and analyze the electrostatic field for image tubes and camera tubes with electrostatic focusing.关键词：Multigrid method;electron optics;Electron lenses2|101|2更新时间：2025-12-08
- 摘要：With the aid of a generalized mutiple scattering theory,the formula for effective electromagnetic parameters εeff and μeff of mixtulre media of random ellipsoid particles are derived and those formula have been applied to the strong scattering of metal particles for the first time.In the meantime the previous formula for only two kinds of dielectric media have been generalized to the （n+1） kinds of electric and magnetic media.The relation of out theory to other theories is also discussed,and theoretical results are in good agreement with the measured data.关键词：Generalized multiple scattering theory;Mixture random media;Equivalent electromagnetic parpmeters;Strong scatlering particles2|141|6更新时间：2025-12-08
- 摘要：Fractal Cantor multi-layered medium is a kind of self-similar structure,with probably wide applications in optics and quantum mechanics.In this paper,an inverse scattering method for this fractal structure is investigated by using a time domain signalflow graph technique to reconstruct the fractal dimension and its self-similar structure from the reflection spectrum.Reconstruction examples are given.关键词：Fractal Cantor;Self-similar structure;Time domain signal-flow graph;inverse scattering3|48|0更新时间：2025-12-08
- 摘要：In this paper the space charge theory for a three-dimensional curvilinear beam-let with transversal initial velocity spread in electron guns composed of non-axisymmetric electron-optical systems is established.As a simple example of application,based on Kino’s plane space charge fluid theory,the space charge density of some three-dimensional curvilinear beamlet with transversal Maxwell initial velocity spread in a long Kino’ sgun is numerically calculated.关键词：3D curvilinear coordinates;Gaussian beamlet;Space charge2|26|0更新时间：2025-12-08
- 摘要：Fairness of DQDB MAN with large files transfer is analyzed in this paper.Based on the performance analysis of a particular node under the condition of large files transfer and the interaction among the nodes,this paper proves that the network will reach a steady state after a transient period and presents the throughput of each node in steady and transient state.The expression of the lenght of transient period is also given.关键词：DQDB MAN;distributed queue;local queue;Transient state;Steady state;Bandwidth balancing mechanism2|24|3更新时间：2025-12-08
- 摘要：The steady state performance of the GSC adaptive antenna system with a Systolic array is analysed in this paper.Based on the referenced],new expressions are proposed for the Wiener Solution,the SJNR,and the Performance Improvement due to Adaption （PIA） of this system.Some problems for constructing a Systolic array are also discussed.关键词：The Generalized Sidelobe Canceller （GSC）;Systolic array;Performance Im-provment due to Adaption （PIA）4|31|0更新时间：2025-12-08
- 摘要：Each of codes has Doppler mismatch in the phase-coded waveforms.Based on the feature of multiplication of m-sequence,this paper proposes a method which expands the permissive Doppler mismatch bandwidth,and analyzes the Dopoler mismatch performance of the method.The method atteuates the sidelobes sensitivity to Doppler mismatch and has longer permissive Doppler bandwidth than the customary method.It’s shown thoat the method is effective by computer simulation.关键词：phase-coded;Doppler mismatch;Pulse combression;matched filter2|79|1更新时间：2025-12-08
- 摘要：The characteristics of noise passing through a circuit are described and the formulas for calculate the noise figure are given.As a typical application,the low-noise design of parallel and feedback arrangements is discussed and the design principles are obtained.关键词：Low-noise design;parallel;feedback2|165|1更新时间：2025-12-08
- 摘要：An adaptive processing system of quasi-stationary signal is proposed in this paper,which consists of three subsystems: adaptive feature extractor,detector of abrupt change and pattern classifier.The optimal system is considered for its adaptive real-time realization.We Choose the two Kalman filters,measurer of whitening degree and Kohonen’s selforg nizing neural network to construct this system.Finally,the simulation results are presented.关键词：Qusi-stationary signal;adaptive system;Artificial neural network;entropy2|89|2更新时间：2025-12-08
- 摘要：The method of pattern recognition with Circular Harmonic Component for the past ten years is briefly reviewed.An image transformation,CHC m-r plane transform,is proposed.Based on CHC m-r plane,a method has been developed for shift,rotation,scale and intensity-invariant pattern recognition.Experiment results for discrimination of aircrafts are given.关键词：image processing;pattern recognition;Circular harmonic filter4|29|0更新时间：2025-12-08
- 摘要：The transient of eletromagnetic waves have been discussed in this paper.Using the boundary-layer theory,the asymptotic solutions of the overlap wave equation are obtained.The wave number is a complex,its image part due to loss of medium denotes the loss of transient electromagnetic waves.Analysis shows that,Maxwell equations are still true in case of transient for lossy medium.Attenuation factor of transient EM waves is exp （-σt /2ε）关键词：电磁波传播;聚焦波模;衰减;瞬态场;边界层理论;渐近解2|78|4更新时间：2025-12-08
- 摘要：The Broadband Integrated Services Digital Network （BISDN） is becoming the dominant research domain of ISDN and the broadband switching is one of the most difficult key technologies in it.This paper proposes a new design method to implement the broadband switching which is based on the Asynchronous Transfer Mode （ATM） and is able to provide integrated switching suitable for both broadband and narrowband communication services.关键词：ISDN;ATM;Broadband switching2|64|0更新时间：2025-12-08
- 摘要：This paper makes a review on significant technical advances in research and development of HDTV broadcasting systems during the past twenty years all over the world.And some issues relevant to this kind of research in China are discussed.关键词：High definition television;compatibility;video compression;Satellite broadcasting systems;Terrestrial broadcasting systems;All digital systems2|32|4更新时间：2025-12-08
- 摘要：The electron beams created in soft vacuum by gas discharge and its major properties are decribed.These beams with high power are very useful for microelectronic and optoelectronic processes and plasma chemistry.The measured Ⅰ-Ⅴ charactristics,spatial intensity profiles,and energy spec trums of these electron beam are shown.Also a new model of the beam mechanism is suggested.关键词：Gas discharge beam;Soft vacuum2|65|0更新时间：2025-12-08
- 摘要：In this paper,the application of OSRC to electromagnetic scattering from two-dimensional homogeneous dielectrtic cylinder is discussed.The third-order OSRC operator is used to analyse the scattering from a homogeneous dielectric cylinder illuminated by a TM or TE polarized plane wave.The results of radar cross-section of dielectric elliptical cylinder are provided,and they are in good agreee-ment with the exact solutions.关键词：EM scattering;Numerical methods;Radiation condition2|48|0更新时间：2025-12-08
- 摘要：Gapacifive posts and diaphragms in a rectangular waveguide are analyzed in this paper by using the method of moments.In this analysis,no restrictions are imposed on the number,shape and arrangement of the posts and diaphragms,therefore the theoretical formulation and the corresponding computer programs are applicable to the analysis of a wide variety of capacifive waveguide elements.Some numerical examples are given and the computed results show a good agreement with the measured and published ones.关键词：Capacitive pasts;Rectangular waveguide;Green’s functions;method of moments2|59|1更新时间：2025-12-08
- 摘要：Based on the theory of coupled model,we study the characteristics and dynamic range of travelling waveguide electro-optical modulator.关键词：Travelling waveguide modulator;Planar microstrip line;Theory of transmission line;Effective index of refraction2|39|0更新时间：2025-12-08
- 摘要：<正> 压电陶瓷已广泛用作滤波器,蜂鸣器及各种换能器。近几年作为压电微位移器件,压电超声马达在精密机械和自动控制等领域的应用日益引入注目。 压电致动器材料通常是锆钛酸铅（PZT）为基的。本文报导具有高压电常数d33及d31,高介电常数ε33T/ε0的四元系压电陶瓷,其基本组成为PMN-PNN-PZT,并以Sr,Bi,Sn,La等掺杂改性,其性能参2|168|0更新时间：2025-12-08
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