Abstract:使用化学沉积方法,在600℃温度下,成功制备锰钴镍(MnxCoyNi3-x-y)O4(MCN)薄膜.传统的固熔烧结工艺合成MCN材料需要的温度条件约为1050~1200℃,与这一温度相比,本文的方法使合成温度降低了许多.随着退火后处理温度从600℃升高到900℃,MCN薄膜的晶粒尺寸大小从20nm增大到50nm.同时还利用红外椭偏光谱测量获得MCN薄膜的介电常数和吸收系数.

Abstract:碲镉汞长波红外576×6焦平面探测器组件是高性能热像仪的核心组件.本文中作者完成了碲镉汞长波红外576×6焦平面探测器组件的设计,利用环孔技术制备出576×6焦平面探测器芯片,经过杜瓦封装、配斯特林制冷机后成为实用的探测器组件.性能参数测试表明:典型的探测率达到1.79×1011cm Hz1/2/W,非均匀性达到14.6%,盲元率达到6.0%,并完成探测器组件的实验室演示成像.

Abstract:The steady-state nonvolatile two-step,two-color holographic recording performance with continuous-wave lights for LiNbO3:Fe:Mn was studied theoretically based on the two-center model.By comparing all of the different electron transfer processes between the deep-trap centers(Mn2 /Mn3 ) and the shallow-trap centers(Fe2 /Fe3 ),our results show that the direct electron exchange between the Mn2 /Mn3 and the Fe2 /Fe3 levels due to the tunneling effect dominates the amplitude of total space charge field under different experimental conditions in LiNbO3:Fe:Mn.This direct electron transfer process also plays a key role in the two-step,two-color holography performance of the crystal.

Abstract:Variable-area hydrogenation of HgCdTe photovoltaic(PV) detectors was studied.It was found that the current-voltage(I-V) characteristic was obviously improved after hydrogenation,wherein dark current was gradually decreased as the hydrogenation area enlarged,and the zero-biased resistance was increased,meanwhile the current noise was reduced.By the comparison of experimental results and numerical fitting results,it was found that the improvement of I-V curves was related to hydrogenation zone.When the hydrogenation process was focused on the N-type zone,hydrogenation effect was mainly due to the reduction of minority carrier recombination centers caused by implantation process,which could increase the minority carrier lifetime.When the hydrogenation was enlarged to P-type zone,the improvement was primarily the result of the oppression of trap density in the surface depletion region,which led to the decrease of trap-assisted tunneling current.So it was concluded that the junctions of PV detectors formed by ion implantation were N P type.

Abstract:Terahertz time-domain spectroscopy(THz-TDS) technique is a newly developed promising spectroscopy technique based on ultrafast laser technology.A method for pesticide detection based on THz-TDS was reported.Two pesticides,methomyl and oxyfluorfen,were investigated to prove its feasibility.THz-TDS was used to measure their terahertz time domain signals.And their refractive index and absorption coefficient between 0.2THz and 2.0THz were calculated by using models based on Fresnel equations.The experimental results indicate that a series of distinct sharp characteristic absorption peaks can be observed clearly and absorption spectra of these two pesticides are completely different.Our analysis show that these absorption peaks may originate from the collective vibration modes and intermolecular vibration,and these fingerprint spectra can be used to identify the samples.Our research indicates that it is feasible to detect pesticide residue by using terahertz technology,and THz-TDS technique is a promising technique for pesticide residue analysis.

Abstract:提出了一种结构新颖的2×2空间功率合成结构.该结构在30~36GHz范围内,回波损耗优于10dB,插入损耗小于1dB.以此结构为基础再利用4块GaAs MMIC单片制作出了一个新型的功率合成器.该功率合成器在31~34GHz的频率范围内,在±0.64dB的增益波动下能得到大于10W的输出功率,并且在31GHz时具有最大的饱和输出功率13.8W,在带内的平均合成效率大于80%.

Abstract:In application of the side-looking millimeter wave radar to monitor traffic flow,the key issue is to recognize background power spectrum.In this study,the traffic radar principles and echo power properties were analyzed.Then,a novel background power spectrum recognition(BPSR) algorithm was proposed which was based on order statistics and coherent averaging.Finally,test results in various environments were presented.Quantitative evaluation and comparison indicate that the algorithm is feasible and the detection performance has been noticeably improved.

Abstract:Pixel classification is one of the most basic and important contents of hyperspectal imagery(HSI) analysis,and SVM based method is very popular in HSI classification for its high efficiency.The importance of samples,features,and classes,however,is not reflected in original SVM based classification model,and the classification effect is deteriorated consequently.In this study,the distance of each sample deviating from its class-center was mapped into the sample as weighting coefficient.And within-class scatter matrix was introduced into the feature weighting measure,and the diagonal elements in SVM equation system were adjusted for the purpose of class weighting.The weighted methods can be used solely or jointly.Experiments show that the proposed weighting methods are helpful to improve the effect of HSI classification.

Abstract:A kind of color building images segmentation method was proposed here.This approach applied area control pretreatment and the watershed algorithm to produce the original regions.The axial symmetry combined with other properties was estimated as region similarity features.The final segmentation was derived by using merging process.And the termination criterion was determined from the distribution(histogram) of the merging costs as an adaptive threshold.The results show that the approach proposed here can produce effective region of building and reduce the noise influence to segmentation.So it's very significant for building image segmentation in 3D reconstruction.

Abstract:Spectral clustering is a similarity-based clustering algorithm on graph theory.When the processed image is very huge,it is very difficult and time-consuming to compute affinity matrix and its eigenvalues and eigenvectors.Aiming at the characteristics of synthetic aperture radar(SAR) images,a two-stage image segmentation algorithm was proposed,in which watershed was used to produce over-segmentation and an improved spectral clustering algorithm was applied to perform final clustering.The new algorithm can not only reduce the noise in SAR images and keep their boundary very well but also is valuable to the application of higher demand for time.To verify the performance of the proposed algorithm,it was applied to segment SAR images,and better segmentation results were obtained.

Abstract:Field-dividing technology is a feasible method to realize wide-view hyperspectral imager.The wide-view hyperspectral imager has to be radiationally matched besides spatial matching between every single view.In this article,the radiational matching technology and key factors for hyperspectral imager were analysised,and the method to realize the matching successfully was introduced briefly.Some fly experimental results of the realized hyperspectral imager were showed.The test results show that the radiational maching is well completed and the precision is in the error of the system allowed by comparing the spectral curves.

Abstract:The time intervals between laser main pulse and the corresponding multiple echoes were needed to measure in photon counting imaging lidar,and the system had to have high precision.The delay line interpolation method was used and a system with the resolution of 27ps was developed.The hardware and the software of the system were presented.The indexes such as the precision and linearity were tested.The results show that the precision can reach 80ps and the linearity is good.

Abstract:针对BSIM3v3模型在35K低温下无法模拟LDD(轻掺杂漏区)所引起的串联电阻异常,提出了可以模拟这一异常的SPICE宏模型.通过修改CMOS器件常温BSIM3v3模型中的一些与温度有关的参数值,得到35K BSIM3v3模型.模拟结果表明,根据此模型进行参数提取后的Ⅰ-Ⅴ特性曲线与实测曲线十分吻合.最后,运用此模型对CMOS传输门和两级运算放大器进行仿真,结果表明LDD串联电阻效应对这些电路产生了重要影响,该模型明显提高了低温BSIM3v3的仿真精度.

Abstract:采用热丝和射频等离子体复合化学气相沉积技术,用旋涂法制备负载催化剂的硅片衬底,以CH4为碳源制备出取向碳纳米管阵列薄膜.利用扫描电子显微镜对不同还原时间和不同N i(NO3)2浓度下制备的催化剂基片和取向碳纳米管阵列薄膜进行形貌分析,用透射电子显微镜和拉曼光谱对碳纳米管进行表征.结果表明,在H2-N2气氛中热还原后硅片上的催化剂粒径均匀,排列致密,利用该法制备的碳纳米管为竹节型多壁碳纳米管,管径分布均匀,管长约5μm.碳纳米管阵列薄膜垂直于硅片衬底生长,生长排列均匀致密,具有良好的取向性.

Abstract:Theoretical analyses and experimental research were done on the laser-induced interference and damage to CCD and CMOS image sensors.The 1064nm laser interference threshold,damage threshold and completely destroy threshold of CCD and CMOS image sensors were measured under atmospheric pressure condition and vacuum condition respectively.Experimental results show that the three aforementioned thresholds of CCD or CMOS sensors have no obvious differences under the two different pressure conditions.Experimental results also reveal that,compared to CMOS image sensors,CCD image sensors are easier to be interfered or damaged or even destroyed,while CMOS sensors have a better anti-jamming and anti-injury ability under each of the two conditions.

Abstract:A novel defected ground structure(DGS) was designed and applied to a flip-chip integrated millimeter wave oscillator.The characteristics of two oscillators with and without DGS were analyzed and compared.Measurement data shows that the phase noise of the oscillator with DGS is reduced by 4~6dB,and the output power of the oscillator is increased by 0.8dBm in comparison with the oscillator without DGS.It is found that,when DGS is embedded in the resonant tank and the output terminal of an oscillator,the phase noise can be reduced and the output power will be enhanced.

Abstract:ZnSe quantum dots(QDs),assembled into the ordered channels of mesoporous silica(SBA-15) under water-free and oxygen-free conditions by hot soap method,were investigated.The microstructures of the mesoporous silica with ZnSe QDs were characterized by X-ray diffraction,transmission electron microscopy image and energy dispersive spectrometry.Their optical properties were studied by UV-visible absorption and fluorescence spectrometry.The results show that the ZnSe QDs have been loaded into the ordered SBA-15 channels.Compared with the bulk ZnSe,the absorbance spectra of the ZnSe QDs immobilized in the channels exhibit a significant blue-shift,which is attributed to the quantum size effect.

Abstract:Thermal mismatch stress for HgCdTe infrared focal plane array was analyzed by finite elements method.According to the analyzing results,two configurations of infrared focal plane array were proposed to reduce the thermal mismatch stress effectively.The reliability of HgCdTe infrared focal plane array was raised obviously.

Abstract:本文主要涉及紫外激光加工技术.通过实验,将紫外/红外两种激光设备对材料的加工结果进行比较,发现在特殊材料加工上,紫外激光相对于红外激光,加工边沿更光滑、效率更高.对于用红外透过率较高的材料加工的红外器件来说,紫外激光在加工中具有明显的优势.