最新刊期
卷 ， 期 9 ， 1992
- 摘要：In this paper, the relaxation frequency formula of the BC laser diode （LD） is theoretically derived, and confirmed experimentally. The high-speed LD module has been built which has broadband modulation property up to 5.3GHz. By using this LD module in 1km optic fiber link, the other properties are measured. It is suitable to transmit C band signal （3.7- 4. 2GHz） from communication satellite into the subcarrier multiplex optical fiber communication system.关键词：optical fiber communication;Laser diode;Sub-carrier multiplex2|59|0更新时间：2025-12-08
- 摘要：With a set of improved basis function of Film-LAPW method in vacuum-jellium region suitable for jellium/slab model, the work function, energy bands and density of surface states of W（001） surface covered with Cs overlayer are calculated with three layers of W slab. The results and the relations among those quantities are analysed, thereby giving relatively clear quantum pictures in this process.关键词：Energy band of solid;Surface electron states;Overlayer-substrate system Cs on W.3|78|0更新时间：2025-12-08
- 摘要：<正> 第二届国际磁性材料物理讨论会（ISPMM’92）于1992年7月2日至5日在北京召开,到会代表260人,其中外国代表83人.收到论文350篇.会议共分11个专题.即基础磁学、磁化过程、新型氮化物磁体、永磁材料、磁记录材料、多层膜、磁性薄膜、微波材料、非晶与纳米晶体,软磁材料及磁性测量.4|11|0更新时间：2025-12-08
- 摘要：In this paper the analytic mode method and numerical mode method for full wave analysis of electromagnetic scattering in cylindrically layered media are discussed. The former is applicable to field analysis under any kind of excitation; and the latter can be used to solve the field in 2-D inhomogenious media efficiently by using the concepts of reflection matrix and transmisioti matrix. Based on the numerical mode matching theory the computer aid analysis code has been given. The computation results are obtained in excellent agreement with the data from two-dimension finite element method （FEM） and the computer time is only one percent of the time of FEM.关键词：electromagnetic scattering;Electromagnetic wave logging;Numerical mode matching2|201|11更新时间：2025-12-08
- 摘要：The expression of a hybrid phase center of an axially symmetric reflector antenna feed source is rigorously derived in this paper from field relevance theory.It is proved that expressions for both linearly polarized and circularly polarized feed sources are completely the same. Thus it provides a theoretical basis for design and adjustment of refector antenna, particularly the modified Cassegrain antenna.关键词：reflector antenna;Phase center;Feed source2|151|2更新时间：2025-12-08
- 摘要：<正> 航空航天部23所成功地研制了SW100-I型大功率短波广播发射机.该机的音频系统选择了脉冲宽度调制式（PDM）,射频系统采用了自动调谐线路,研制中运用了计算机优化设计,关键零部件采取了独特的设计技术和特殊的制造工艺,1～8频道的输出功率在100kW以上,效率大于65％,9～11频道的输出功率接近100kW,效率达61％.由于采用了超蒸发冷却系统,整机结构紧凑,该机振幅频率特性约±0.5dB,非线性失真约2.5％、噪声电平小于-55dB,载波跌落小于1％、边带功率损失小2|42|0更新时间：2025-12-08
- 摘要：This paper presents an extended Chinese Remainder Theorem （CRT） valid for moduli non-mutually prime in integer residue sub-rings. By dealing with noisy ambiguous data, an algorithm based on the CRT is developed for data ambiguity resolution, which can be used to accomplish the simultaneous ambiguity resolution on both range and velocity in medium PRF pulse doppler radars. In addition, the condition and probability of correct ambiguity re-sloution are also analysed.关键词：ambiguity;Ambiguity resolution;Chinese remainder theorem;algorithm2|118|9更新时间：2025-12-08
- 摘要：Pascal triangle transform is proposed to calculate monomials, then a novel systolic structure is given to implement Pascal triangle transform, which makes monomial calculation much simple. Based on this, we propose sequential and parallel structures to calculate the moments of binary images. The method has the following advantages: 1. its calculation cost is low, 2. there is no limit on the order of the moments to be calculated, 3. no multiplication is needed, 4. it is easy for the hardware and software implementation, 5. monomial calculations are independent of input images.关键词：Moment;Pascal triangle transform;Monomials;Systolic structure;Sequential algorithm;parallel algorithm2|43|3更新时间：2025-12-08
- 摘要：A fuzzy clustering method for image segmentation based on two-dimensional histogram is presented. It utilizes the gray level information of each pixel and its spatial correlation information within the neighborhood. By using the fuzzy c-means （FCM） clustering algorithm, the membership of pixels is obtained and then the image is segmented in terms of the values of the membership. The experimental results show that the misclassification pixel number using the proposed method decreases about by a factor of 4 compared with the Otsu method or the entropic method.关键词：模糊C均值聚类算法;二维直方图;图象分割2|732|28更新时间：2025-12-08
- 摘要：In this paper, a convolution-characteristics method is introduced for analysis ofthe time response of multiconductor transmission lines. Its uniqueness is that nonuniform transmission lines with frequency-dependent losses and arbitrary terminals can be analyzed by it.关键词：多导体传输线;时域响应;付里叶变换;卷积;特征法2|169|3更新时间：2025-12-08
- 摘要：A nondiagonal extinction matrix and the phase matrix in vector radiative transfer equation for a layer of nonuniformly-oriented and nonspherical scatterers are derived. By using the integral equation of radiative transfer and the Mueller matrix, complete polari-metric scatterings from a layer of nonspherical scatterers are numerically calculated. The copolarized and depolarized backscattering coefficients, the degree of polarization of scattered Stokes vector, the phase difference between vv and hh waves, and the functional relation to some parameters are quantitatively discussed.关键词：Nonuniform orientation;Nonspherical scatterers;Complete polarimetry;Mueller matrix3|78|3更新时间：2025-12-08
- 摘要：: The iteration technique is presented for solving three-dimensional vector integral equation. The field distribution in dielectric objects illuminated by a given wave is obtained, thus the scattering field outside a dielectric object is determined. The numerical results from the method are compared with the ones from other methods. The effectiveness and accuracy of the method are proved from the investigation, and the problem encountered in other methods are avoided.关键词：Field iteration method;Three-Dimensional dielectric object;electromagnetic scattering2|27|1更新时间：2025-12-08
- 摘要：Based on cylindrical harmonic expansion, this paper analyses circular waveguide loaded with an eccentric dielectric rod. By using Graf’s addition theorem for Bessel functions, the field on the outer conductor is matched. Thus an equation for propagating constant of each mode is obtained. Numerical results show that the convergence is reliable.关键词：柱谐基函数;加法定理;传播常数2|53|1更新时间：2025-12-08
- 摘要：In this paper, a matching method of stochastic sign change criterion is theoretically anlayzed. It is proved that the sign change number at matching point is maximum when the overlap and geometrical distortion are negligible. At the same time, the ability of anti-overlap is discussed. Finally, a lot of simulation experiments are done on DPS-8/52 computer system with two machine part images. The theoretical analysis and experimental results show that the matching method of stochastic sign change criterion not only can correctly complete image matching under the situation of SNR<1, but also has the ability of anti-special overlap.关键词：The number of stochastic sign change;Image matching;Anti-overlap;similarity measure;low SNR2|16|1更新时间：2025-12-08
- 摘要：This paper firstly summarizes classification, development and applications of the planar antennas commercialized or reported by now, then describes the key to main technology and the possible solutions of the related problems. Some new achievements and important problems demanding prompt solution are introduced.关键词：planar antenna;microstrip antenna;Satellite TV reception antenna2|203|5更新时间：2025-12-08
- 摘要：A formula for evaluating the equivalent shunt admittance of an inclined slot in the narrow wall of a rectangular waveguide is presented. By using the infinite image array technique and the duality of electricity and magnetism, the difficulty involving the divergency of the series which is related to the dyadic Green’s function in the guide has been avoided. The computation problem of self reaction of the magnetic current outside the guide is also discussed. The numerical results show that good agreement between the theory and experiment has been achieved.关键词：Edge slots;Equivalent admittance;Image technique;mutual impedance4|59|4更新时间：2025-12-08
- 摘要：The formulas are developed to calculate 3-D radiation field and gain of microstrip antennas on finite truncated cone-cylinder by applying the UTD. These formulas are also applicable to the finite truncated cone and cylinder. Examples are given on the calculation of 3-D radiation patterns and gain of the finite truncated cone. The results of calculations agree well with the experimental ones.关键词：The finite truncated cone-cylinder;microstrip antenna;3-D radiation pattern;gain2|33|1更新时间：2025-12-08
- 摘要：In this paper, a new structure called "Q-multiplier bandstop structure" is proposed for the realization of second-order high-Q RC bandstop filter. A design example and experimental results are given. As negtive feedback is used, the new struccture has low sensitivity. The circuit is also simpler than others and has great practicability.关键词：filter;Active RC;High-Q;Bandstop2|159|2更新时间：2025-12-08
- 摘要：A high performance, W-band 2nd harmonic Gunn oscillator has been developed. A common waveguide cavity is designed for both the fundamental and 2nd harmonic frequency, Mechanical tuning range is up to 15GHz（100-115GHz）, output power is over 5mW and maximum output power is 18.5mW. The linear electronic tuning range is more than 250MHz. This VCO has been used in 2.6mm wave band phase-lock local system of large millimeter wave radio telescope of PMO.关键词：Gunn diode;Fundamental frequency;2nd harmonic frequency;oscillator;Radialline2|33|1更新时间：2025-12-08
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