最新刊期
卷 ， 期 4 ， 1990
- 摘要：A pressed multi-layer nickel matrix cathode which is specially suitable for application in high-resolution electron beam devices is presented. By the multi-layer structure, both high emission current density and low sublimation rate of barium can be simultaneously obtained. Another merit is the choice of activators. Some of them provide the high initial activation for mass production, while others guarantee the low rate of dispensing barium required for long life.2|39|0更新时间：2025-12-08
- 摘要：The space charge theory of relativistic electron beam is studied and the general theory has been formulated in this paper. The space charge wave equations for relativistic electron beam have been derived, the relativistic kinetic voltage is defined and the physical explanation is described. The theorem of relativistic kinetic energy has been derived, and the normalized model of relativistic space charge wave is derived as well.2|62|1更新时间：2025-12-08
- 摘要：In this Paper, the far field RCS analytical formula of a plate partially coated with a lossy medium strip is derived from the high frequency diffracted coefficients of a wedge with impedance surfaces,superposition theorem and physical optics approximation. The results in the paper are verified in our experiments and agree well with the references.2|25|1更新时间：2025-12-08
- 摘要：The time domain current distribution and radiation characteristics of a dipole near a finite conducting plate are investigated by solving the time domain electric field integrodifferential equations with the time stepping approach. The differences of the effects between the finite and infinite reflecting plates on the transient input currents and far radiation fields of the near pulse antennas are analyzed. A numerical technique is presented and adopted to eliminate the oscillations at later response time.2|30|0更新时间：2025-12-08
- 摘要：So far the application of method of lines is restricted to electromagnetic boundary value problems （EM BVPs） in rectangular or compound rectangular regions with straight line boundaries.In this paper, a model of method of lines for 2-D EM BVPs defined in regions with curved boundaries is established based on the same method for EM BVPs in compound rectangular regions.The cut-off wavelengths of dominant mode in rectangular-to-circular waveguide transition and the equivalent circuit parameters of rectangular waveguide E-plane bends are calculated.The method is verified by the obtained numerical results.It is shown that the method possesses some advantages such as easy formulation and less computation time.2|53|6更新时间：2025-12-08
- 摘要：In this paper the concept of the hybrid-fault incremental circuit is proposed, a new linear approach for fault diagnosis of nonlinear circuits-the cut-fault diagnosis method is given, and its relation to the node-fault diagnosis method and branch-fault diagnosis method is discussed.2|36|2更新时间：2025-12-08
- 摘要：ECG base-line drift cancellation is an important problem.This paper uses segmenting 3-order Hermite interpolation for base-line drift correction,and presents a linear transformation rules of interpolation basic functions when the signal length of interpolation interval changes owing to the changing of heart rate.This correction technique has higher precision of approaching and less amount of computing, and it can be used for real-time ECG monitor. In addition, this paper presents a design of hardware circuits for computing the Hermite interpolation function,and the time for computing one point is only 12μS.2|128|2更新时间：2025-12-08
- 摘要：This paper deals with the problem of high-resolution angle of arrival estimation in the presence of coherent signal sources. The receiving antenna is restricted to uniform linear array of sensors.Special attentions are paid to the estimation of signal subspace by the array measurements. A general procedure is developed that, in the first place, estimate the vector （s）of the signal subspace in N（the number of the array elements）dimensonal vector space C, and secondly, estimate the orthogonal projection matrix of a signal subspace in a lower dimensional space C, where M<N. We have shown that the well known spatial smoothing technique can be considered as a special case of the new approach. Simulation results are presented to show the effectiveness of the new approach.2|160|3更新时间：2025-12-08
- 摘要：In this paper, the problem of reconstructing discrete signal from its partial sample points and Fourier transform magnitude is converted into a typical combinatorial optimization problem, and a recently proposed effective optimization algorithm, Simulated Annealing method, is utilized to tackle this problem. A general simulated annealing signal reconstruction algorithm is developed. The results of computer experiments have shown that the algorithm is very effective and can correctly reconstruct the signal with a computational complexity much less than that by previous algorithm.2|51|3更新时间：2025-12-08
- 摘要：This paper presents a new algorithm for the high-resolution estimation of arrival angles of narrowband plane waves. In the algorithm, a post-processing technique is used to decrease the perturbation caused by noises. The post-processing of the noise subspace includes constructing a matrix composed of the elements of the vectors which are in the noise subs-pace and replacing the matrix by its reducing rank approximation. The simulation results have shown the effectiveness of the algorithm.2|179|1更新时间：2025-12-08
- 摘要：This paper presents a variable step size adaptive filtering algorithm （VS-NLMS）.An estimated cross-correlation coefficient between the input reference signal and the error signal is used as the variable step size.Compared with the conventional fixed step size adaptive filtering algorithm （NLMS）, the VS-NLMS algorithm can achieve much lower misad-justment noise in the steady state with the same convergence speed and tracking capability. The excellent properties of the VS-NLMS algorithm are confirmed by theoretical analysis and computer simulations.2|763|30更新时间：2025-12-08
- 摘要：Based on the modern computer vision technique-two-view vision theory andgeometrical principle, a new algorithm for shape from texture is proposed.The new method has many advantages over the past algorithms, such as less computational requirement, simpler structure and wider versatility for different textures.2|29|0更新时间：2025-12-08
- 摘要：A BAG-based vectorization method suitable for microcomputers is proposed to process the image of drawings. Because the image processing is based on a totally new graph data structure, the processing speed increases by a factor of 6 approximately. The experimental results show that this method is effective.2|23|9更新时间：2025-12-08
- 摘要：Based on backward error analysis in numerical perturbation theory, the finite wordlength effects on the performance of adaptive sidelobe canceller （SLC） are studied in this paper.A new upper bound formula of the performance parameters has been derived and great improvement in bound precision is reached as compared with the ordinary method. As a result,a quantitative evaluation of the array performance by finite wordlength effects can be made. Some concise formulas for wordlength selection in digital sidelobe canceller are presented as well. The theoretical results well agree with the computer simulations.2|43|1更新时间：2025-12-08
- 摘要：A definition on feeds phase center of reflector antennas of arbitrary shape is presented in this paper, and computational method is given which may be used to improve the performance of deformed reflector antennas. As an example, a practical calculation is carried out for 8m reflector antenna, and the satisfactory result is obtained.2|306|5更新时间：2025-12-08
- 摘要：The principal image coding techniques of the first-generation and their theoretical bases were introduced briefly in this paper. Its weakness which limits image coding compression ratio was analyzed in detail.The contents and developing direction of the second-generation image coding technique were presented with relevant techniques described briefly.2|57|3更新时间：2025-12-08
- 摘要：In this paper we describe the 1.5μm weakly coherent fiber communication system with external cavity semiconductir laser. This is the first coherent fiber communication system with semiconductor laser established domestically. We achieve 70～140Mbit/s signal transmission over this system with good quality. The single mode fiber used in this system is six kilometers long. The experiments show that by using external semiconductor laser we are able to establish weakly coherent fiber system like that established by using DFB laser.2|31|4更新时间：2025-12-08
- 摘要：An efficient computer method for obtaining sensitivity function of linear SC circuits is presented. The new method uses fast, efficient, numerical-type algorithms to determine the symbolic sensitivity function. Large change sensitivity in terms of increments to the nominal values of elements and sensitivity function in terms of element values themselves can be obtained in the actual program.2|12|0更新时间：2025-12-08
- 摘要：GaAs Gunn harmonic oscillators operating from 120GHz to 140GHz are presented.The oscillators deliver an output power of 3.5mW at 139GHz and 13.5mW at 120GHz.The active n-region of the devices used is 1.6-2.0μm in length, with carrier densities of 0.9×1010 to 1.3×1010cm-3. These packaged GaAs Gunn diodes are commercially available in China.2|48|1更新时间：2025-12-08
- 摘要：This paper deals with fault diagnosis problems in analog circuits, taking the design tolerances on the nonfaulty elements into consideration.A new diagnosis method based on simulated annealing combinatorial optimization technique is proposed. An effective and computational algorithm is presented. Finally, an example illustrating the application of this method is included.3|58|3更新时间：2025-12-08
- 摘要：In this paper, a class ol Prior Tries Set （PT） soft decision decoding algorithms which have far less time complexity and better decoding performance than classical chase algorithms is presented.2|86|1更新时间：2025-12-08
- 摘要：The SAW MZOS storage correlators/convolvers with center frequency of 80MHz, bandwidth of 7MHz, convolution efficiency of -57dBm have been developed. A method for measurement of MZOS interface state density is presented. The effect of MZOS interface state density on storage is studied. Finally some of the problems associated with MZOS storage correlators/convolvers are discussed.2|20|2更新时间：2025-12-08
- 摘要：In this paper, the theoretical analyses and evaluations of parameters (or a LSAM system operating at 100 MHz are presented and the practical experiments are illustrated. Some samples are successfully imaged on TV screen.2|44|2更新时间：2025-12-08
- 摘要：The study of the radiation field at any distance of a dual-shaped reflector antenna is presented, and as an example, near and far field of a dual-shaped Cassegrain antenna is calculated. The computational results show good agreement with the measured data. Therefore, a new conclusion about dual reflector antenna is obtained. Besides, a new method to calculate accurately disastrous field value round an antenna is given. It is an effective technique for solving electromagnetic compatibility （EMC） problem related to an antenna.2|53|1更新时间：2025-12-08
- 摘要：The deposition of SiO2 films on GaAs and AlGaAs by RF sputtering is described in this paper. The properties of films such as etching rate, refractive index, hole density, IR absorption spectra and Auger electron spectra have been measured and analysed.It is found that the sputtered SiO2 film is effective as a mask for Zn diffusion in GaAs and AlGaAs/GaAs.2|30|0更新时间：2025-12-08
- 摘要：A new structure of C-Band dual mode reciprocal latching ferrite with combined function of phase shift and variable polarization is proposed in this paper. Both theoretical analyses and experimental results demonstrate its multi-polarization function. Compared with conventional twin-slab ferrite phase shifters, this new structure is more compact.2|53|8更新时间：2025-12-08
- 摘要：<正> 北京信息工程学院是机械电子工业部部属的一所专门培养信息科学技术专业人才的高等院校,其前身是一九七八年创建的北京大学第二分校,一九八五年一月正式命名为北京信息工程学院。 学院坐落于首都北部郊2|16|0更新时间：2025-12-08
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