Abstract:High quality SrBi 2Ta 2O 9 (SBT) ferroelectric thin films were fabricated on platinized silicon substrate by PLD. Electronic transport properties of SrBi 2Ta 2O 9 ferroelectric thin films in temperature range of 10 to 300K were studied. The conduction mechanisms in the thin films were analyzed. The results indicate the existence of two conduction mechanisms in SBT ferroelectric thin films. Due to the SBT layered structure, the carrier transport can be divided into two parts: internal transport, which is between the (Bi 2O 2) 2+ layers, and external transport, which is across the (Bi 2O 2) 2+ layers. Especially, behavior of electric transport of the polaron as an internal transport carrier is first observed in the SrBi 2Ta 2O 9 ferroelectric thin films. Activation energy of the internal transport carriers is E a ~ 0.0556 eV. The results can be helpful in understanding the low DC leakage in SBT films at room temperature.

Abstract:使用二次离子质谱分析(SIMS)方法研究了As在碲镉汞分子柬外延样品中的扩散系数．获得了在240℃．380℃和440℃温度下As在碲镉汞材料中的扩散系数，并发现它与退火过程中Hg的分压有关，且Hg空位对As的扩散有明显的辅助增强作用．研究表明在低温段的240℃／24—48小时的退火中As的扩散非常有限，对样品中As的浓度分布影响不大，而在高温段380℃／16小时和440℃／30分钟退火中，As扩散较为明显，能使原来的PN突变结变缓．综合比较As杂质的电学激活以及As扩散因素，高温段440℃／30分钟的退火条件较理想．

Abstract:Short wavelength infrared (SWIR) focal plane arrays (FPAs) working at room temperature have many important military and cosmonautic applications. The dimensions of detectors in FPAs have gradually been reduced. Then the problem of the increase of effective optically sensitive area in photovoltaic detectors by conventional technology has been more thought of. The response of n-on-p HgCdTe photodiodes at 300K was measured by laser beam induced current(LBIC). From the results, we may see that the increase of effective optically sensitive area does exit, and the lateral diffusion of carriers to the junction periphery is the main reason.

Abstract:In order to effectively improve the classification performance of neural network, first architecture of fuzzy neural network with fuzzy input was proposed. Next a cost function of fuzzy outputs and non-fuzzy targets was defined. Then a learning algorithm from the cost function for adjusting weights was derived. And then the fuzzy neural network was inversed and fuzzified inversion algorithm was proposed. Finally, computer simulations on real-world pattern classification problems examine the effectives of the proposed approach. The experiment results show that the proposed approach has the merits of high learning efficiency, high classification accuracy and high generalization capability.

Abstract:The characterizations of Te-rich PbTe layer thermal-evaporated from an excess of Te (<1 mol.%) evaporable materials were reported. The results reveal that the films obtained are polycrystalline and have single-phase NaCl-type PbTe crystal structure. It is also demonstrated that the films have homogeneous surface morphology and homogeneous distribution of Te-rich components along the layer in the range of 170 nm. The study on mid-infrared optical constants of film surface-polished indicates that the influence of surface scattering on optical properties is very small.

Abstract:Effects of the dielectric loading on the transmission properties of frequency selective surfaces(FSS) were preliminarily explored by experiment, especially in the thickness, loading patterns of the dielectric and the sensitivities of the forementioned parameters to the varying angle of incidence. The experimental results show that the resonant frequency of FSS decreases with the dielectric loading, the transmission ratio and resonant frequency are changed with the different dielectric thickness, and the dielectric symmetrically loading can stabilize the FSS transmission characteristic as the angle of incidence is varied.

Abstract:利用调制式的椭偏仪测量了掺镧锆钛酸铅PLZT薄膜的电光系数．首先用反射椭偏测量的方法得到薄膜的折射率(n)和厚度(d)，然后利用透射椭偏在线测量的功能，在样品上加电场(E)，得到薄膜的折射率的改变8n．最后用测量得到的厚度，折射率以及折射率的改变来计算薄膜的电光系数．该仪器的灵敏度很高，很适合较薄的膜层材料电光性质的测量．

Abstract:Spectral characteristics preservation and high spatial resolution retention are two key issues in image fusion. Different applications may require different balances between the two issues. A new controllable remote sensing image fusion method based on wavelet transform was proposed. At first, the two images were decomposed into sub-images with wavelet transform. Secondly, these sub-images were fused in wavelet space based on their characteristics. Lastly, a fused image was achieved by inverse wavelet transform. By introducing the parameters, the balance between spectral characteristics preservation and high spatial resolution retention can be achieved at different levels. With some combination of the parameters, the visual effects and the statistical parameters indicate that the fused result is slightly better than, or comparable to, those of the commonly used image fusion methods.

Abstract:The method of improving image spatial resolution of the optical instruments with linear sensors in the three-axis body-stabilized platform was proposed by changing the sensors' relative positions as well as increasing the over-sampling ratio in some degrees. The basic iterative algorithm and the error spreading induced by the method were quantitively analyzed, and the certain relationship between the image spatial resolution and the image SNR was also presented. The technological feasibility of the method was proved by the patent technology of SPOT-5 HRG. This technology can been applied in the polar-stationary satellite platform under the current conditions.

Abstract:采用有限元方法对“类矩形”保偏光纤的应力双折射进行了分析,给出了保偏光纤横截面上的应力分布图形及应力双折射分布曲线;应用全矢量电磁场有限元方法,计算了保偏光纤的两个偏振模场的分布、传输常数及模式双折射.在给定模拟条件下,纤芯的应力双折射约为 3. 33×10-4,其模式双折射约为 3. 72×10-4.计算结果表明,这种“类矩形”保偏光纤与其它保偏光纤相比,有几个明显的优点,即有更佳的应力传递效果、均匀的应力场分布、更大的应力双折射.

Abstract:By combined the Monte Carlo method and curved ray tracing technique, the thermal emission characteristics of an anisotropic scattering semitransparent medium with gradient refractive index was analyzed. The semitransparent and specular emerging surface of the medium layer was parallel to an opaque and diffuse substrate wall. The influence of the scattering albedo and scattering phase function to the apparent emittance was investigated. The results show that the influence of the scattering to the apparent emission characteristics is important. In the medium with linear refractive index distribution, when strong scattering happens, the apparent emission will reduce with the increasing of the optical thickness of the medium. This phenomenon is quite different from that in conventional semitransparent bodys.

Abstract:采用有效折射率方法EIM(Effective Index Method)和二维束传播算法(2D-BPM)对SOI(Sillcon-on—insulator)波导弯曲损耗的改善方法进行了模拟分析．模拟发现，在波导连接处引入偏移量和在波导外侧刻槽等两种不同方法都能有效减小弯曲损耗，并且后者的效果更明显．同时通过实验获得了验证．对R=16mm、横向位移为70μm的弯曲波导，通过刻槽方法将插入损耗降低了5dB，基本消除了弯曲所带来的附加损耗.

Abstract:Special property of complementary suppression modulated transmission (CSMT) of bacteriorhodopsin (bR) film was used to establish a new kind of optical filter,which can be used to remove incoherent bright-background in optical image. This new kind of optical filter was demonstrated and its behavior was analyzed theoretically. The calculated results showed that the quality (the contrast, the transmitted intensity and the space distribution) of the processed image was affected by the parameters (concentration and lifetime of M state) of bR film and the intensity of the bias light. With the increasing of bR film concentration, the transmitted intensity and the curvature degree of the space distribution of the transmitted intensity decreased, and the contrast increased to the maximum and then decreased to zero. By prolonging the lifetime of M state, the transmitted intensity, the curvature degree of the space distribution of the transmitted intensity increased and the contrast increased to the stable value. Accompanying the increase of the intensity of the bias light, the transmitted intensity decreased, the space distribution was not changed, and the contrast can be increased to 1. But when the concentration of bR film, the lifetime of M state and the intensity of the bias light were too large, the processed image might be distorted.

Abstract:报道980nm大功率底发射垂直腔面发射激光器的结构、研制及器件的阈值电流、输出功率和光谱特性．在室温(24℃)下，5A连续电流工作时，出光孔径400μm的器件激射波长为984．1nm，输出功率达到1．42W，是目前所能见到报道中最高的．研究了出光孔径600μm的器件在连续工作时，激射波长、光谱半高宽随注入电流的变化以及在重复频率100Hz，脉冲宽度50—1000μs条件下的输出功率、效率与注入电流的关系．

Abstract:Based on the theory of four-port resonant filters, the characteristics of filters with ring resonators were numerically simulated by using two-dimensional FDTD method. The relationship between the coupling length of MMI and the filtering features was also simulated . Two narrow-band filters with ring resonators based on GaAlAs/GaAs planar waveguide were designed and fabricated. The measurement on filtering feature was carried out. It coincides well with that from the numeric computation.

Abstract:Basing on PKI and obeying the criterion of hospital management and workflow patterns, certificate authority system and digital signature manage system were designed. The interface of CA and DSMS integrating with various hospital information systems ( such as RIS,HIS and PACS) was realized and the security verification of system information was completed. Thus, the integrity, authorization and authentication of digital medical information being used in hospitals, were ensured.

Abstract:线性调频连续波雷达对于匀速运动目标的回波经过混频以后还是一个线性调频信号(LFM)．从LFM信号中提取密集运动目标的距离和速度参数是个比较复杂的问题．本文提出了一种基于目标运动补偿和逐次消去(“CLEAN”)技术相结合的检测方法，该方法避免了估计多分量LFM信号参数问题，同时又消除了多普勒效应对密集运动目标检测的各种影响．仿真结果表明该方法不但克服了LFMCW雷达在密集目标检测中的困难，而且比传统方法降低10dB左右的检测信噪比门限．