空域红外图像的背景噪声分析及预处理

文中就如何提高空域背景下弱小目标的信噪比问题展开讨论，基于对背景噪声的统计分析提出了自适应滤波和小波分析两种图像预处理算法，达到抑制背景噪声，增强小目标的目的，并将二者进行了性能分析。     

Studies on interfacial adhesion,tensile and thermal characteristics in blends of polystyrene/novalac resin

Specific interactions generate stability of the component parts in blends. Present work aims to elucidate intermolecular interactions in polystyrene/novolac blends by means of Infrared spectroscopic studies. It was found that strong interactions were observed at band 3095 cm^?1 assigned to aromatic C? H stretching vibrations, at band 2980 cm^?1 assigned to aliphatic C‐H stretching vibration and at band 1635 cm^?1 assigned to C?C stretch vibration of aromatic ring system. Maximum interaction was observed in blend consisting polystyrene/novolac (80:20 by parts, in this study it is blend B). Mechanical and thermal properties of the blends were also studied. Tensile strength data was found maximum in blend B. Nonisothermal method of Freeman and Carrol was used to investigate the kinetics of thermal degradation. The reactions were studied by thermogravimetry in nitrogen atmosphere. Decomposition of the blends was found in consecutive stages. The activation energies were determined for each stage of reactions. From thermal studies, blend B was found to be most stable. A degradation mechanism was suggested by compiling the reports of previous authors. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4630–4636, 2006     

Thin film transmission matrix approach to fourier transform infrared analysis of HgCdTe multilayer heterostructures

The ability to achieve high-yield focal plane arrays from Hg_1−xCd_xTe molecular beam epitaxy material depends strongly on postgrowth wafer analysis. Nondestructive analysis that can determine layer thicknesses as well as alloy compositions is critical in providing run-to-run consistency. In this paper, we incorporate the use of a thin film transmission matrix model to analyze Fourier transform infrared (FTIR) transmission spectra. Our model uses a genetic algorithm along with a multidimensional, nonlinear minimization Nelder-Mead algorithm to determine the composition and thickness of each layer in the measured epitaxial structure. Once a solution has been found, the software is able to predict detector performance such as quantum efficiency and spectral response. We have verified our model by comparing detector spectral data to our predicted spectral data derived from the room-temperature FTIR transmission data. Furthermore, the model can be used to generate design curves for detectors with varying absorber thicknesses and/or different operating temperatures. The consequence of this are reduced cycle times and reduced design variations.     

Molecular beam epitaxial growth of Cd<Subscript>1−y</Subscript>Zn<Subscript>y</Subscript>Se<Subscript>x</Subscript>Te<Subscript>1−x</Subscript> on Si(211)

We report on the first successful growth of the quaternary alloy Cd_1−yZn_ySe_xTe_1−x(211) on 3-in. Si(211) substrates using molecular beam epitaxy (MBE). The growth of CdZnSeTe was performed using a compound CdTe effusion source, a compound ZnTe source, and an elemental Se effusion source. The alloy compositions (x and y) of the Cd_1−yZn_ySe_xTe_1−x quaternary compound were controlled through the Se/CdTe and ZnTe/CdTe flux ratios, respectively. Our results indicated that the surface morphology of CdZnSeTe improves as the Zn concentration decreases, which fits well with our previous observation that the surface morphology of CdZnTe/Si is poorer than that of CdSeTe/Si. Although the x-ray full-width at half-maximums (FWHMs) of CdZnSeTe/Si with 4% of Zn + Se remain relatively constant regardless of the individual Zn and Se concentrations, etched-pit density (EPD) measurements exhibit a higher dislocation count on CdZnSeTe/Si layers with about 2% Zn and Se incorporated. The enhancement of threading dislocations in these alloys might be due to an alloy disorder effect between ZnSe and CdTe phases. Our results indicate that the CdZnSeTe/Si quaternary material with low Zn or low Se concentration (less than 1.5%) while maintaining 4% total Zn + Se concentration can be used as lattice-matching composite substrates for long-wavelength infrared (LWIR) HgCdTe as an alternative for CdZnTe/Si or CdSeTe/Si.     

Arsenic-doped mid-wavelength infrared HgCdTe photodiodes

The recently developed Te-rich, liquid-phase-epitaxy growth technology for low arsenic-doped mid-wavelength infrared (MWIR) HgCdTe with p-type doping concentrations <10¹⁵ cm⁻³ has enabled the fabrication of n⁺/p photodiodes using the damage associated with a boron ion implantation. The diode properties are presented and compared to similar diodes fabricated in p-HgCdTe doped with Group IBs. The attraction of the arsenic-doped diode technology is associated with the fact that the arsenic resides on the Te sublattice and is immune to the Hg interstitial fluxes that are present in the diode-formation process. This leads to minimal diode spread, limited primarily to the n⁺ region and, hence, a potential for use in really high-density infrared focal planes. At the same time, the Hg interstitials generated in the diode-formation process should purge the photodiode volume of fast diffusing species, resulting in a high-quality, diode-depletion region devoid of many Shockley-Read recombination centers. These aspects of diode formation in this material are discussed.     

Experimental investigation of the normal spectral emissivity and other thermophysical properties of pulse-heated Ni-Ti and Au-Ni alloys into the liquid phase

1. Introduction Metal working industry needs accurate thermo- physical properties of liquid metals and alloys as input data for different simulation routines to im- prove the performance of their products. Within this paper we continue the systematic investigation of the dependence of emissivity of binary alloys on the relative concentration of the constituent elements (for a previous paper see [1]). 2. Experimental method A fast ohmic pulse heating technique is applied to heat metallic wire-s…     

激光美容仪温度探测报警系统研究

利用激光在皮肤中的传导及应用红外传感器探测皮肤温度的原理 ,设计激光美容手术温度控制模型 ,控制激光手术安全。本系统具有提高激光手术的安全性能 ,推广激光治疗的作用     

星载激光告警探测系统设计

采用光谱识别型与成像型相结合的原理,提出了两种凝视型星载激光告警探测系统的 设计方案,并利用CODE V和ZEMAX光学软件对两种探测系统进行了仿真模拟与优化。这 两种探测系统能对目前典型的四种波长,即1. 315μm、2. 7μm、3. 8μm和10. 6μm的红外激光进行预警,其理论分析和仿真结果都达到了指标要求。     

美欧低空防御导弹发展现状

重点介绍了与空空导弹扩展有关的美欧低空防御导弹的发展现状, 给出了主要型号的系统配置和技术性能。     

MEALINESS DETECTION IN APPLES USING TIME RESOLVED REFLECTANCE SPECTROSCOPY

Mealiness is a textural attribute related to internal fruit disorder that is characterized by the combination of abnormal softness of the fruit and absence of free juiciness in the mouth when eaten by the consumer. Time‐resolved laser reflectance spectroscopy was used as a tool to determine mealiness. This new technique in agrofood research may provide physical and chemical information independently and simultaneously, which is relevant to characterize mealiness. Using visible and near infrared lasers as light sources, time‐resolved laser reflectance spectroscopy was applied to Golden Delicious and Cox apples (n = 90), to characterize batches of untreated samples and samples that were stored under conditions that promote the development of mealiness (20C & 95% RH). The collected database was clustered into different groups according to their instrumental test values. The optical coefficients were used as explanatory variables to build discriminant functions for mealiness. The performance of the classification models created ranged from 47 to 100% of correctly identified mealy versus nonmealy apples.