Abstract:We have studied the optical spectra of low-dimensional semiconductor systems by calculating all possible optical transitions between electronic states. Optical absorption and emission have been obtained under different carrier population conditions and in different photon wavelengths. The line-shapes of the peaks in the optical spectrum are determined by the density of electronic states of the system, and the symmetries and intensities of these peaks can be improved by reducing the dimensionality of the system. Optical gain requires in general a population inversion, whereas for a quantum-dot system, there exists a threshold value of the population inversion.

Abstract:Starting with the nature of welding seams, the artical studiws Changes of the microstructures and chemical components of welding seams duning the process of welding, then discuss the effects of these changes on active infrared images of reflection. Through theoretical and experimental analyses, it is well known that active infrared technology can be applied in the investigation of industrial welding seams. The method put forth in the article mainly aims at the practical application of industries, and is characterized by rapid, of high precision, on-line in real time. The precision is up to 0.1mm. It takes only 0.02s to segment an active infrared image on a P-700 personal computer.

Abstract:A novel dual-amplitude pulse interval modulation (DAPIM) for optical wireless communications is discussed. The symbol structure, the spectral properties, the bandwidth requirement and error performance of DAPIM in a nondispersive channel are presented. DAPIM shows a better compromise between bandwidth and power requirements compared with OOK, PPM, and PIM. DAPIM with 5 bits and 6 bits persymbol is attractive in terms of optical power and bandwidth requirements.

Abstract:分析了红外焦平面探测器的非均匀性机理和各种非均匀性校正算法，提出两点多段非均匀性校正算法，该算法避免了二点校正算法的低精度和多点校正算法的大运算量．在红外多谱段相机上的应用结果表明二点多段非均匀性校正算法具有运算量小、精度高、实用性强的优点。

Abstract:用射频磁控反应溅射在石英玻璃和硅片上沉积氧化钒薄膜 .利用X射线衍射 ,X射线光电子谱 ,原子力显微镜 ,分光光度计和电阻测量手段对沉积薄膜结构、形貌和性能进行了测试 .结果表明 ,沉积薄膜的电阻温度系数大于 1.8% /℃ ,方块电阻为 2 2± 5kΩ/□ .

Abstract:对阿基米德斩波器及其工作状态进行了模拟，分析了探测器像元的曝光时间、曝光顺序、信号读出及其对后续信号均匀性处理的影响．结果表明：探测器曝光的非均匀性与信号读出模式直接影响后续信号的均匀性处理，阿基米德螺旋线的参数、探测器几何尺寸、斩波器与探测器的相对位置等均影响探测器的曝光顺序和电荷均匀性．在热成像系统总体设计以及电子处理系统设计时，必须综合考虑斩波器各参数的影响。

Abstract:A new technique of histogram double equalization for the infrared thermal image is presented. At the same time of having histogram equalization, the gray redundance is removed and the gray level is reconstructed with equal interval in the whole display region. Then the continuous gray images are obtained. The problem of the large dynamic range of input signal against the small dynamic range of output display is solved in the signal processing in infrared thermal image system. Theoretical and experimental results show that the detail and definition of infrared thermal image are greatly improved.

Abstract:A novel chain bunching cavity of gyroklystron amplifier, which is the clustered-cavity with TE mode, is studied. Analysis and calculations have been done by using three-dimensional electromagnetic code. The effect of loss medium on Q factor of bunching cavity is discussed, and the influence of the number of coupling-holes on resonance characteristic is also analyzed. Simulation results are in good agreement with cold-test experiment. Finally, a chain bunching cavity is designed for the developing Ka-band frequency-tripling gyroklystron amplifier.

Abstract:利用FY-IC极轨气象卫星扫描辐射计的通道1(0．58—0．68μm)、通道3(3．55—3．95μm)和通道6(1．58—1．64μm)所提供的探测数据进行了水云光学厚度和粒子有效半径的反演试验．在非水汽吸收波段(如通道1)，云的反射函数主要是云光学厚度的函数，而在水汽吸收波段(如通道6)，云的反射函数主要是云粒子大小的函数．因此当云光学厚度较厚时，可利用通道1和通道6反射率，或通道1反射率和通道3亮度温度同时计算出云的光学厚度和有效粒子半径。

Abstract:Generally, the segmentation of a medical image is difficult, because the medical image is often corrupted by norrupted by noise, and the anatomical shape in the medical image is complicated. In this paper presents a new geometric active contour scheme for medical image segmentation. First, we regularize the attraction force field in the geometric active contour model to extend the capture range of the object boundaries, and improve the ability of convergence to the concavities. Then, using a multi-scale scheme improve the boundary detection accuracy. In addition, combining the regularization and the multi-scale method, the proposed scheme can effectively suppress and eliminate the noise and the spurious edges in the medical images. Furthermore, the topology of the deforming curve can naturally change without and special topolygy handing procedures added to the scheme. This permits synchronously extracting several anatomical structures. The experiments on some medical images obtained from different medical imaging methods demonstrate that the proposed approach is competent for medical image segmentation.

Abstract:A product correlation algorithm of image registration based on feature and spatial-temporal correlation was presented. At first edge features of real-time images and base image are extracted by using Bubble wavelet. Then, the base image is shifted according to position guided by inertia system, in order to make theposition of real-time image in base image to be same. Finally, owing to the direct ratio between probability of registration and area of registration, the sequential product correlation matrix is added, and the registration position is searched in the added matrix. This method has overcome the shortcoming that the probability of registration decreasing with the increasing of the area owing to geometric distortion, and has improved the probability, precision and robustness of registration.

Abstract:A new method based on wavelet decomposition is presented for the restoration of turbulence-degraded images. For this method, two turbulence-degraded images are used as the inputs, for which the multi-scale decompositions are made using wavelet transform. The discrete values of the two turbulence PSFs in large scales can be estimated by mean of the Fourier frequency spectrum of the images in low frequency subbands. Removing blur is performed in the low frequency subbands of the images while reducing noise and preserving edges are made in the high frequency subbands. The experimental results show that the proposed method is highly effective for it not only greatly reduces the computational complexity and speeds up the restoration but also enhances the quality of restoration and the ability of resisting-noise well.

Abstract:By transmitting wide band LFM pulse and using stretch method, high resolution range profile of target can be obtained, and the range of still object can be exactly measured. While, the ranging precision and the quality of range profile may be influenced by the velocity of the object. To overcome these shortcomings two-step stretch processing method can be used. Theoretic derivation and the simulation results, that shows that by using this method range estimation with high precision and velocity roughly estimation can be obtained, are presented. By using these estimation values, the range tracking, profile, status forecasting and MTI(Moving Target Indication) process can be realized.

Abstract:把HJT—K—6型导电环安装在高温高速真空的模拟工程环境中，测量了其在0．133Pa真空下，环境温度为常温与100℃以及其转速分别为0．16m／s、0．32m／s、0．63m／s、1．25m／s时传输的电压信号随时间的变化及其信噪比，并用X—Y记录仪记录实验结果．结果表明，高速转动和高温使电压信号的信噪比增加．即使环境温度为100℃、转速为1．25m／s时导电环传输的电压信号的信噪比也不低于278：1．说明在高速高温真空环境中HJT—K—6型导电环对电压信号的传输影响很小，能把转动环上的电信号很好的导出真空室，可以在类似工程环境中使用。

Abstract:A FLIR image segmentation algorithm based on genetic algorithm and fuzzy set theory was presented. The method defines different member function for the object and background of the image to transform the image into fuzzy domain with maximum fuzzy entropy. The procedure for finding combination of a, b and c is implemented by genetic algorithm, thresholding image into object and background by maximizing the fuzzy entropy. The experiment results show that our proposed method gives better performance and higher calculation speed than other general methods with good real-time by using genetic algorithm.

Abstract:Several Cd 0.9 Zn 0.1 Te wafers with different properties are characterized by FTIR transmission. It is found that the IR transmission can be used qualitatively to deduce the quality of the Cd 0.9 Zn 0.1 Te wafers. The wafers with higher transmission have homogenized concentration distribution, lower dislocation density, and higher resistivity. According to the variation of IR transmission with wavenumber, IR transmission spectra can be classified into four types with different qualities. These results are initially analyzed based on the mechanism of Cd 0.9 Zn 0.1 Te IR absorption.

Abstract:A Ka-band antipodal finline waveguide-to-microstrip transition was analyzed and simulated by HFSS software. The several factors of simulation result for affecting performance of transition are analyzed, and a design curve of transition available for project application is obtained. Based on the curve, the waveguide-to-microstrip transition is designed. The insertion loss of transition is below 1 dB in the Ka-band. Experimental results coincide well with the design curve.

Abstract:The space equalization method (SEM) is put forward in this paper to eliminate the amplitude and phase errors among antennas caused by mechanical manufacturing errors and array edge effects. After array mutual coupling calibration (MCC), an adaptive nulling algorithm based on SEM is derived, which greatly improves jammer cancellation performances. The experimental results demonstrate the advantage of SEM.