Abstract:研究了Si在AlxGa1-xAs(0≤x≤1)中的掺杂行为.为比较Al組份对Si掺杂浓度的影响,在用气态源分子束外延生长(GSMBE)掺Si n型AlxGa1-xAs(0≤x≤1)的所有样品时,n型掺杂剂Si炉的温度恒定不变.用Hall效应测量外延层的自由载流子浓度和迁移率,用X射线双晶衍射迴摆曲线测量外延层的组份.测试结果表明,当AlxGa1-xAs中Al组份从0增至0.38时,Si的掺杂浓度从4×1018 cm-3降至7.8×1016 cm-3,电子迁移率从1900 cm2/Vs 降至 100 cm2/Vs.这与AlxGa1-xAs材料的Γ-X直接-间接带隙的转换点十分吻合.在AlxGa1-xAs全组份范囲内,自由载流子浓度隨Al组份从0至1呈 "V"形变化,在X = 0.38处呈最低点.在x＞0.4之后,AlxGa1-xAs的电子迁移随Al组分的增加,一直维持较低值且波动幅度很小.

Abstract:采用水平滑移石墨舟液相外延生长技术在n型(100)InAs衬底上生长了InAs0.96Sb0.04薄膜.在1.5～5.5 eV光子能量范围采用紫外-可见光椭圆偏振光谱仪于室温下测试了其介电函数谱ε(E).基于电子带间跃迁和联合态密度理论,采用S. Adachi的MDF模型对ε(E)进行了拟合,并计算了各种临界点电子跃迁对ε(E)的贡献.结果表明:实验数据与模型吻合得非常好,E1和E1 Δ1跃迁发生在布里渊区(BZ)的Λ轴或L点,分别对应于M1型临界点Λv5→Λc6(或Lv4.5→Lc6)和Λv6→Λc6(或Lv6→Lc6)跃迁;E2跃迁是由于M1型和M2型鞍点能量简并引起的,沿着BZ的Σ和Δ轴方向.

Abstract:The microscan techniques studies both domestic and overseas were introduced briefly and the principles and categories of mircoscan techniques used for IR staring imaging were discussed. According to different actuating elements, such as servo motors and ferroelectric ceramics, the principles, structues and signal read-out of microscan were described in detail. Finally, the merits of microscan were summarized.

Abstract:In order to make cost-versus-quality of launched satellite trade-offs, computer technology can be used to simulate the physical process of infrared imaging from land surface to archiving images before launching satellite. The available simulating methods are not able to simulate big-footprint scene and complicated land cover types by using thermal radiation transfer models and imaging physical models. Due to this reason, we selected a scene model to setup simulation system which composed land surface scene, atmospheric effect scene and sensor imaging scene. In this study, all kinds of relevant methodology about simulation utilizing scene models were analysed, a proposal of thermal infrared remote sensing simulating system was suggested which could be used to simulate wide area scene and different land cover types. This work is a new approach for infrared imaging simulation and it is helpful for relevant researching works.

Abstract:A group of reference calibration coefficients for CBERS-2's CCD data were provided by cross calibration method by using LANDSAT5 TM data.The validation for the cross calibration shows its feasibility.A method,which is based on 6S model and isochronous meteorological information on sensing time,was used in the atmospheric correction of CBERS-2's CCD four bands.Validation analysis was conducted by comparisons of corrected and uncorrected reflectance data including normalized difference vegetation index(NDVI).It finds that the corrected reflectance of CCD3 and CCD4 increases clearly and the NDVI of vegetation ascends while the NDVI of nonvegetation descends.

Abstract:设计了由正负微透镜阵列和压电陶瓷驱动器组成的微型光扫描器,它工作于中、短波红外光及可见光等波段,微透镜阵列规模为256×256元、单元直径为50μm,扫描视场角约为6.6°,扫描频率可达200Hz,体积小到几个立方厘米.实验测试表明微扫描器的设计参数与实验测量结果基本相符.

Abstract:Based on the traditional four-variable model and the unique characteristics of 60GHz millimeter wave, the large/ small scale attenuation was used to simulate the amplitudes and delay bins were used to estimate the delay, thus, a simple and effective millimeter wave model was created, which fits the actual situation well. According to the program float chart, MATLAB was used to simulate and analyze. After the computer simulation, the result shows that this model accurately fits the 60GHz wave transmission characteristics and it can also analyze them statistically.

Abstract:提出一种采用双对极鳍线-微带过渡的Ka频段2×2波导基功率合成结构.这种两路过渡结构在31.0～40.0GHz范围内实测背对背插损小于0.9dB,回波损耗优于12.0dB.组合四块GaAs MMIC功率单片制作的这种新型功率合成器,在32.0 ～36.0GHz频带、±1.21dB增益波动下获得6W的最大饱和输出功率,带内平均合成效率为82%,且在25W的直流功耗下也保持了极佳的散热性能.这些测试结果验证了本方案的可行性.

Abstract:针对现有协同神经网络参数优化方法的不足,提出了一种基于免疫克隆算法的参数优化方法.与在平衡注意参数条件下的算法和在不平衡注意参数条件下基于遗传算法和模拟退火算法的优化方法相比,新方法具有全局兼局部寻优能力,不易陷入局部极值,并且迭代步长是自适应调整的.对纹理图像与遥感图像的分类识别结果表明:新方法不仅具有更快的收敛速度而且具有更优的分类识别性能,同时验证了注意参数及所有参数对各原型模式之间竞争态势的影响,从而达到更佳的分类识别效果.

Abstract:On the basis of passive millimeter wave(MMW) detection principle,radiometer antenna temperature and output signal models were established.Armored target MMW radiant temperature in actual combat condition was computed and analyzed.The necessity for passive MMW stealth at the same time of radar stealth research,that is MMW radiation characteristics control,was pointed out.

Abstract:Contour detection plays an important role in shape-based object recognition tasks. It is an intractable problem of how to automatically detecting the contour of object from natural scenes. This is mainly because there exist plenty of extraneous elements in background. Parallel physiological and anatomical studies showed that the response to the stimulus in the receptive field suffers iso-orientation surround inhibition. Thus the less of this suppression in areas where there is a change in orientation results in enhanced saliency of isolated edges and region boundary. We proposed a biologically motivated model of contour detection, which reduces edges from a texture background, while retaining object contours. The inhibition step may be expected to improve contour detection performance when images contain objects of interest on a textured or cluttered background.

Abstract:The working principle of the laser induced breakdown spectroscopy(LIBS) was interpreted.The elemental recognition process was discussed.The reason for elemental recognition error was analyzed.A recognition method based on the standard samples was suggested.A LIBS experimental system was setup and the experiments for the standard and unknown samples were carried out.The feasibility and the recognition advantages of the method were proved by the experimental results.

Abstract:A new evaluation method, Correction-Rate, was proposed, which can quantitively compute the effect of NUC, and some experiments were performed to verify its advantages. Correction-Rate uses the temporal noise as a reference standard to evaluate NU of the infrared images. It can not only reflect the display effect, but also the temperature-measuring precision. This measurement can be used in comparison of the performances of IRFPA system and evaluation of the effects of NUC methods. It is very meaningful for the further research of NUC.

Abstract:A novel thresholding algorithm was presented to achieve an improved ship infrared object segmentation performance.The proposed algorithm uses discontinuity preserving smoothing algorithm based on mean shift procedure to filter the powerful noise without the loss of the ship object information.The regions produced by mean shift filtering can be represented by a planar weighted region adjacency graphs that incorporates topological information of the image structure and region connectivity.Under the graph representation,region merging algorithm based on SST-minimax was applied to partition the regions into different class,such as sky background,sea background and ship object.Due to the less nodes produced by the regions of filtered image than the original image,the region merging based on SST-minimax algorithms has much less computational complexity.A large number of examples are presented to show the superior performance of the proposed ship infrared object segmentation algorithm.

Abstract:A method for designing and training artificial neural network based on genetic algorithm(NNDT) was presented.NNDT trains both architectures and weights of networks simultaneously.The problem that the one-to-one relationship between the topology and the encoding can not be kept was solved effectively.Heuristic method was used to constraint the probability of topology mutation and the trend of the choice of the kind of mutation.Also,the niching mechanism was used to protect the mutation of network topologies.The experiments results show the efficiency and rapidity of NNDT.

Abstract:The microstructural changes originated from Cr doping in 0.2PZN-0.8PZT piezoelectric ceramics were investigated by means of XRD and Raman scatteringl The phase transition from rhombohedral to tetragonal and the increase of crystal tetragonallity are caused by Cr addition. The studies about the lattice parameters and the phase transition through Raman scattering are confirmed by XRD. So, the microstructural changes induced by doping in the piezoelectric ceramics with tetragonal and rhombohedral structures simultaneously can be revealed through the analysis of the Raman vibration modes in different structures.

Abstract:The effect of disorder on transmission spectra of two-dimensional photonic crystals with transfer matrix method(TMM) was investigated.Specifically,the effects of disorders of lattice structure,radius of cylinders,shape of cylinders,and the dielectric constant on the transmission spectra of a two-dimensional square lattice crystal with frequency were studied by using the RAND function in Fortran,respectively.The numerical simulation results show that,in the case of weak disorder,the effect of the shape of cylinders is the most significant while the effect of radius of cylinders is the weakest. The characteristics of transmission can be well maintained if the disorders are limited within a certain range.In the case of strong disorder,a common phenomena found in different disorders is the localization of photons at low frequencies.The width and position of the band gap are affected by the strong disorder.In addition,a number of resonant modes are found in the transmission.

Abstract:The automated segmentation of the tongue body is a premise to establish an automatic diagnosis system according to the features of tongue in traditional Chinese medicine(TCM),whose qualities have great effect on the performance of tongue diagnosis.However,automated tongue segmentation is difficult due to the complexity of pathological tongue,variance of tongue shape and interference of the lips.Here a novel algorithm for automated tongue segmentation was presented based on hyperspectral tongue image data acquired from a hyperspectral imaging system.First,by finding the spectral angle(SA) between each pixel and every other pixel in the original data cube,a transformed data cube was constructed.Thus,each spectrum in the transformed SA cube contained information about spatial changes in the tongue scene.Then,each spectrum in the transformed SA cube was analyzed with a one-dimensional edge-detector.Finally, the whole contour of the tongue was extracted from the hyperspectral tongue image according to the edge detected.Experimental results demonstrate that the novel tongue segmentation algorithm can segment the tongue more accurately.