Abstract:Deep Level Transient Spectroscopy (DLTS) was used to study the irradiation-induced defects in GaAs (50A)/GaAlAs (50A) superlattice. The existence of metastability of such defects was demonstrated, and their transition temperature was studied. The reason why these characteristics can not be observed in the bulk materials is pointed out.

Abstract:The density of states (DOS) of two-dimensional (2D) electrons in perpendicular magnetic fields was reliably extracted from the magneto-capacitive response of double-barrier structures. The model calculations with a Gaussian-like DOS were compared with the experimental C vs. B curves, measured at different biases and temperatures. The results show that the fittings are remarkably good, and the Landau level model DOS is obtained. Unlike the cdnventionally used heterostructure method, the new measurements have no in-plane series magneto-resistance of the two-dimensional channel involved. So, the DOS can be obtained as well even in the quantum Hall regimes. In addition, the physical quantities obtained from the fittings, such as the subband level EO, the Fermi level EF, the 2D number de.nsity N2D and the Lande factor g*, all show oscillatory change with the magnetic field.

Abstract:用３个特征频率的爱因斯坦模型，以Ｇｒｕｎｅｉｓｅｎ参数γｉ和约化的电子－声子耦合强度（ｇ＾２Ｆ）Ｗｉ为参数，较好地拟事子Ｇｅ和ＧａＡｓ的线膨胀系数与能隙的温度关系的实验曲线，结果表明ＴＡ的声子的负的Ｇｒｕｎｅｉｓｅｎ参数是引起低温区Ｇｅ和ＧａＡｓ的线膨胀系数反常的原因，同时，Ｇｅ和ＧａＡｓ的价带项状态的（ｇ＾２Ｆ）ｗｉ为正值，而导带底状态的相应量为负值。

Abstract:The MIS structure of p-type Hg0.76Cd0.24Te bulk material was prepared and its capacitance-voltage characteristic was measured by using a self-established differential capacitance spectrometer. On the basis of Chu's experimental model, the experimental data were fitted and the subband structure in the n-type inversion layer was obtained. The experimental result is in good agreement with that calculated from the revised self-consistent theory.

Abstract:A new definition of similarity for the bipolar WTA neural network model and its implementation are presented. A threshold is added to the system for distinguishing input patterns that are not one of the memory patterns or do not have enough ioformation to be recognized. The threshold value is related to the requirement of error tolerance.

Abstract:Binary serial-coded-filters (BSCFs) were designed baized on the optimization functions of the Hopfield model. Less filters are heeded to carry out the same recognition task, compared with other methods. The error tolerant capacity is also very strong. All target objects can be correctly recognized when the characteristic codes are properly chosed.

Abstract:Based on Kukhtarev's band-conduction model. the relationship between two-wave coupling gain and carrier concentration in photorefractive LiNbO3 crystal is analyzed. The result indicates that the gain increases with the carrier concentration and reaches a saturation value. The exponential gain coefficients of Ce:LiNbO3 crystals with different Ce content have been measured and the experimental results are in good agreement with the theoretical ones.

Abstract:报道了ＫＮｂＯ３：Ｆｅ在５１４．５和６３２．８ｎｍ二波耦合增益系数随温度（２９０－３７０Ｋ）变化的实验结果，分析研究了温度对暗电导、电光系数和扩散场的影响，通过对电光系数ｒ５１为主的实验和理论曲线和拟合，得到了室温（３００Ｋ）暗电导和光电导之比Ｂ＝σｄ／σｐ及其它参数值。