Abstract:It is of particular interest to characterize the frequency spectrum of signal sources at submillimeter wavelengths.The heterodyne-mixing and direct-detection(Fourier transform spectrometer,FTS) methods were introduced to measure thefrequency spectrum of a submillimeter CW source(phase-locked and tunable from 460-520 GHz).A 500-GHz supercon-ductor-insulator-superconductor(SIS) tunnel junction was employed as a mixer for the former method but a direct detectorfor the latter.The measurement results are compared.

Abstract:根据有效介质理论，用Maxwell-Wagner等效公式计算细胞悬液中的平均场．然后基于时变场中单细胞膜电压第二计算模型，用场近似等效方法，建立了毫米场辐射下悬液中细胞膜电压计算模型．模型表明悬液细胞膜电压变化和毫米波的功率、频率、细胞半径、细胞排列及细胞的浓度有关。

Abstract:测量了一批不同组分的铌酸钾锂晶体Raman光谱，发现晶体中位于C格位的Li离子浓度对晶体Raman光谱产生了强烈的影响：低Li含量晶体中[NbO6]^7-八面体所对应的3个Raman特征光谱线没有发生峰分裂，在100～400cm^-1范围出现的小峰与C格位Li离子浓度相关；当晶体中Li离子浓度增加时，与v5所对应的Raman峰在散射几何为X（ZY）Z对应的光谱中加宽．v2振动模式在两种散射几何中均出现分裂峰，并在100～400cm^-1范围出现小峰数量增多；当Li离子浓度接近晶体化学组分时，微扰进一步加强，v5所对应峰分裂成3个峰，v1和v2振动模式发生部分分裂，在100～400cm^-1范围小峰更为突出．

Abstract:The cause of the target fade-out and the ghosting artifact in NN nonuniformity correction scheme for infrared focal plane array(IRFPA) was studied.It was found that ignoring target edge and updating correction coefficients blindly in the NN-NUC scheme were the cause of the problems.Based on this consideration,an edge-directed NN-NUC scheme(ED-NN-NUC) was proposed to eliminate the ghosting artifact and the target fade-out.The comparison experiment with simulated data and real IRFPA infrared data shows that our viewpoint is correct,and the proposed scheme is effective.

Abstract:A novel left-handed microstrip transmission line(LH-TL) structure was presented.Based on this structure,feed lines with composite right/left-handed transmission line(CRLH-TL) structure for microstrip arrays were also presented.By controlling the lengths of LH-TL.and RH-TL parts in CRLH-TL, naught phase shifts of the transmission line can be obtained.As an application,the CRLH-TL has been used as feed line in series fed millimeter wave microstrip arrays.Numerical results show that,by means of the CRLH-TL,the insertion phase shifts at excited ports of microstrip elements can be eliminated.As a result,the inherent beam shifts disappear.

Abstract:MMW Costas frequency-coded radar is a kind of high-range-resolution radar, and motion compensation is the key to realize high range resolution. A motion compensation method based on time domain was proposed, and the accuracy of estimating velocity was also analyzed. Simulations show that this method is feasible and fast.

Abstract:In the millimeter Linear FMCW radar system,the echo Doppler signal quadratic modulated by the target acceleration will cause the Doppler spectrum aberration and reduce the detection performance and parameter estimation precision.In this study,an optimal model based on the Maximum Likelihood(ML) method and its fast algorithm for velocity and acceleration estimation fitted for Gaussian noise were presented.Furthermore,the CRB of the parameter estimation of LFM under normal gauss circumstance was also derives.It provides the real low bounds for variance of estimated parameter.

Abstract:半导体致冷器在环境温度变化大，热传导不稳定，温度调节时间要求快等恶劣条件下工作时具有复杂的热电．特性，基于小信号线性化方法得出了半导体致冷器在复杂环境下的线性动态模型，推导结果表明该模型有两个极点和一个零点，并且模型随工作条件的变化而变化．基于平均意义上的动态模型，采用模糊自适应PID控制算法和脉宽调制技术设计了半导体致冷器冷端的温度控制系统．阶跃反应表明该温度控制系统具有良好的动态性能和稳态品质，并具有良好的抗干扰特性，制冷10％的时间约为70s，稳态误差非常小，达到0．1℃．在简单环境下工作．其温度控制效果优于0．1℃．实验亦表明该温度控制系统在常温环境下，最大制冷温度与环境温度之差达到23℃，且随着控制温度的降低，阶跃反应的时间也越来越长，主要是和半导体致冷器的制冷效率、热沉的散热功率和半导体致冷器的供电电流饱和有关．

Abstract:The pre-launch calibration of the water vapor channel onboard FY-2B geostationary meteorological satellite was made in the Lab's vacuum container.The change of sensor's characteristics post-launch is normally monitored by the onboard blackbody.However,since the blackbody calibration path adopts different objective optic path,it is hard to make the in-orbit absolute calibration for the WV channel of the satellite.The pre-launch calibration of FY-2B's WV channel was introduced,and the calibration processing method with the quantized relation derived from in-orbit electronic calibration,as well as the inter-calibration for the channel 12 of HIRS/3 aboard NOAA-17 was also deseribed.

Abstract:For the absorbing-scattering semitransparent coatings with smooth surface and diffuse opaque substrate, the propagation model of the incident spectrum was derived and the spectral radiative transfer was solved by Monte Carlo method. The effects of the optical thickness, medium scattering and substrate reflection on the bi-directional reflection of the coating surface were analyzed. The results show that the reflection of an absorbing-scattering semitransparent coating is obviously anisotropic even if the Fresnel reflection on surface is not taken into account, and its BRDF is quite different from that of an absorbing coating.

Abstract:In order to detect objects accurately,an image thresholding approach named two dimensions(2-D) maximum entropy was proposed to do infrared image segmentation.By using the 2-D histogram of image,the 2-D maximum entropy method not only considers the distribution of gray information,but also takes advantage of the spatial neighbor information.However,its great computation was often an obstacle in application.The threshold vector was obtained by using a new optimization algorithm,namely,the particle swarm optimization algorithm (PSO).The new way was proposed to realize the 2-D maximum entropy method instead of exhaustive search method.And it is 300~400 times faster than the traditional method.Through the example of segmenting the infrared image,the proposed method has been proved to be a fast method of segmenting infrared image.

Abstract:A PLKF(pseudo-linear Kalman filter) was presented for tracking a moving target by using multi-stations of IRST systems.The initial value of the filter was attained from the pseudo-linear equations,which improves the tracking accuracy and speed of the filter.Results of the simulation of tracking a moving target by PLKF and EKF(extended Kalman filter) illustrate: for 3 or 4 stations,the tracking accuracy of PLKF is more advantage than that of EKF at the beginning of the tracking;for 6 stations,the PLKF and the EKF have the same tracking accuracy.

Abstract:By using the compact density matrix approach and displacement harmonic variant and numerical calculation methods,the linear and nonlinear intersubband refractive index changes(RICs) in a semi-parabolic quantum well with applied electric field were investigated in detail.Numerical calculations on GaAs were performed for the dependence of RIC on the incident optical intensity,the frequency of confined potential of the semi-parabolic quantum well and the strength of applied electric field.Results reveal that the RICs in the semi-parabolic quantum well system sensitively depend on these factors.

Abstract:大气特性与地物发射率是影响陆温反演精度的主要因素,不同的分裂窗表达式用于陆温反演存在不同的反演结果,其中两通道辐射量线形组合形式的分裂窗算法受大气影响最小,反演温度的误差也最小.其反演温度的误差与大气透过率和大气向上辐射无关,但与地物的发射率、大气向下辐射相关.分裂窗表达式B(λ,′Ts°)=a.I(λ1)+b.I(λ2)+c中的反演系数a、b与大气向上辐射无关,但分别与通道1、通道2的大气透过率成反比.当定标点发射率不完全一致时,二者还与大气向下辐射相关;相反,如果定标点发射率完全一致,二者与大气向下辐射无关.使用辐射量线性组合的分裂窗形式反演陆温时,当大气向下辐射与地物的P lanck辐射越相近,误差越小.

Abstract:The Primary design of a Ka-band fundamental wave TE_(01) gyro-traveling wave tube(gyroTWT) amplifier was present.Employing a PIC code,gyroTWT was simulated numerically,and the details and the relations of parameters were presented.The results indicate that an over 450 kW output power and 50dB gain can be obtained from the amplifier by simulating under the condition of 100 kV voltage,20 A current,1.27 T magnetic field.The efficiency exceeds 22.5 percent and the bandwidth is about 5 percent.

Abstract:The borophosphosilicate glass(BPSG) layers as the filling coatings to silica-based planar lightwave circuits were obtained by using plasma enhanced chemical vapor deposition with SiH_4/N_2O and PH_3,B_2H_6.The influence of dopants on refractive index of BPSG layers was discussed and the methods related the refractive index of BPSG layers to PH_3 and B_2H_6 gases flows were suggested.The annealing effects of BPSG layers were studied on its optical features and surface map at different annealing conditions.By using multiple deposition followed by annealing,the perfect BPSG layers,which are without void and gap and with fine smoothness,were fabricated.

Abstract:A simple self-seeding scheme was demonstrated for tunable dual-wavelength optical short pulse generation with enhanced sidemode suppression ratio. The two wavelengths and their separation can be tuned in a flexible manner by adjusting two fiber Bragg gratings and an optical delay line. The sidemode suppression ratio of the output pulses achieved is close to or better than 30 dB over the wavelength-tuning range of 20.7 nm. The system is simple and robust and convenient for dual-wavelength tuning.

Abstract:Automatic image thresholding segmentation based on two-dimensional Maximum Correlation Criterion(MCC) was proposed.On the base of two-dimensional histogram,this method maximizes the correlations associated with the distributions of the background and object classes to obtain the optimal threshold, and it has greater resistance capability to noise than one-dimensional MCC.At the same time,Genetic Algorithms(GA) was used in the establishment of the optimal threshold based on the two-dimensional MCC.The experimental results show that the proposed algorithm achieves a good segmentation quality and shorten the computational time.