By using the method of transverse-section, the reflective coefficient of diffraction in the open-end of resonators with slowly varying eross-section under general unsym-metrical mode condifions have been found by introduction of a "phase correction factor". Diffraction boundary conditions in the open-end are obtained, and can be used to solve multimode problems. Several different types of open resonators are studied, and methods of engineering calculation also briefly discussed.

In ths paper, the design considerations of the high- efficiency high- gain broadband klystron are described. Its buncher has been studied by using small signal gain and large sigual efficiency programs. The buncher bandwidth of 10% with small signal gain greater than 50 dB can be obtained for 7-cavity klystron. The bandwidth of 10-15% can be obtained for a 8-cavity klystron. The design methods and measured results of two types of output cireuits are introduced. The bandwidth of the filter type output circuit is about 7.5-10% and that of the overlapping mode two gap cavity output circuit is about 10-12%. Two types of S-band broadband klystron have been constructed and tested. Teh experimental results are given as follow. The klystron with a filter type output circuit has 1 dB equi-drive bandwidth of 7.5% with efficiency of 38% and gain of 43 dB. The klystron with an overlapping mode two gap cavity output circuit has 1 dB equi-drive bandwidth of 10%. Their output power is greater than 2.5 MW.

The concepts of positive (negative) root complete directed trees and positive (negative) root complete directed k-trees and a positive (negative) root complete directed trees analysis method for linear active networks are presented. This method is the unification of complete trees method and directed trees method. It does not involve any sign problem and cancellation terms problem.

In this paper some novel adaptor circuits are proposed to realize the unit element wave switched eapacitor filters driven by two phase clock signals. These circuits are very insensitive to the bottom plate parasitic capacitanees. To realize an adaptor only one unit-gain buffer is needed. The effects of top plate parasitie capacitanees and switch parasitic capacitanees on the adaptor are analyzed. The results show that the effects of the parasitics are small and can be reduced further by changing only one of the capacitances. These circuits are adaptable for realizing programmable filters and very useful to the PLC real-time speech synthesis. As an example, a 5th order unit element low-pass filter is given. The experimental results are in good agreement with the theoretical ones.

By using available tbeoretical results, a 0.11-2GHz, -20 dB, dual-directional coupler is designed. The associated practical design procedure and algorithm can be used as a gcncral procedure for designing several types of couplers or MIC transmission lines, provided they have rectangular bounds. Experimental results show in good agreement with tbeoretical ones.

In this paper, the algorithm of using B spline function for geometric transformation of digital image is presented. Given a group of special regular controlling points, B spline function for transformation is formed. The algorithm guarantees precise correspondence between controlling points, higher precision can be obtained. It can be implemented in a minicomputer digital image processing system with a special hard-wired device.This paper also points out that the geometric window transformation can be implemented automatically.

Study of the diffusion of Cd and Zn into InP at temperature of 450-700℃is described. The effects of various impurity sourees, such as Cd, Zn and their compounds on the diffusion are studied in detail. Using the ratio of the square of the diffusion depth x² and the time t as the mcasure of the diffusion velocity, a plot of x²/t versus temperature T is given. It is found that the diffusion velocity of Cd is slower, especially when CdP₂ is used as diffusion source, and thus the diffusion depth and concentration of Cd are easier to be controlled. So it is a more ideal diffusion impurity source. The complicated phenomena of Cd-and Zn-diffusion in InP are explained with neutral complex proposed by Tien (1979).

The irradiation damages to Al gate MOS capacitors in electron beam lithography (EBL) and the effects of annealing on damages at low temperature (<500℃) are given. The degrees of damages depend on the eleetron energies (10-30keV) and the charge dosages (10^-6-10^-3C·cm^-2). The research on the effects of high energy (30keV) and large dosage (10^-3 C·cm^-2) on damages is important and useful to EBL with vapor development and without devolopment. The damages of concentrations of interface states can reach one to two orders f magnitude. Under constant charge dosages, the damages of flat-band voltages are independent of the variations of the electron energies in certain energy ranges; and under constant electron energies, the damages of concentrations of interface states are independent of the variations of charge dosage in certain dosage ranges. The annealing can eliminate the damages of the flatband voltages, but can not eliminate completely the damages of the concentrations of the interface states.

A small area Josephson tunnel junction is fabricated with suspended metai mask which is made from ordinary razor blades. The junction overlap is formed by two succeeding evaporations of susperconductor materials at oblique angles. The advantages of this technique are that the fabrieation processes ean be performed continuously without opening the evaperation chamber and also it is suitable for making a small area tunnel junction. The I-V charaeteristic of a tunnel junction made by this technique has been taken at 4.2K.

Starting from the temperature characteritics of the transistor current gain, the temperature-dependent law of the collector current just as the current gain begins to fall-off is studied theoretically and experimentally. It is verified that the physical reason is the base widening effect.

The incoporation and the behavior of impurity Cd in VPE of GaAs were studiecl using elemental Cd as a dopant in Ga-AsCl₃-H₂ system. The distribution coefficient of Cd and its solubility in GaAs were found to be 0.01-0.001 and 4×10¹⁸ cm^-3 respectively. The relationship between the electrical properties and epitaxial parameters has been discussed. As a result, the epilayers whh p-n or p⁺-p^-n junction were prepared using elemental S and Cd doping techniques. The materials obtained in this way have a smooth surface morphology and a good interfacial properties.