典型卫星表面材料近红外偏振特性分析

为了表征典型卫星表面材料的近红外偏振特性,基于微面元模型并综合考虑镜面散射及漫散射来描述目标表面的反射特性,引入镜面系数及漫反射率来明确两种反射对偏振度的影响,并考虑实际粗糙材料表面存在的遮蔽效应,建立一种更完善的多参量偏振双向反射分布函数模型,进而推导出适用于粗糙材料表面的光学反射偏振度表达式.对典型卫星表面材料进行近红外偏振实验,采用遗传算法从实验数据中反演卫星表面材料的多参量数值,进而得到偏振信息仿真曲线.结果 表明,该多参量偏振双向反射分布函数的仿真值与实验测试值能够较好的吻合,不同卫星表面材料的近红外偏振特性有较大分布差异.     

近地面水平方向大气偏振辐射传输仿真与验证

近地面水平方向偏振成像是地基目标观测的有效手段之一。目标偏振信息在大气传输中受到大气气溶胶及分子等散射和吸收作用的影响,叠加了非目标偏振信息,干扰了目标本身偏振特性参数的提取。因此,对大气的偏振影响研究具有重要意义。针对近地面水平方向偏振观测,基于单次散射假设,仿真计算了不同气溶胶光学厚度条件下的大气偏振辐射传输特性,并开展了外场偏振特性传输实验验证。仿真结果表明,地表贡献可以忽略;随着气溶胶光学厚度的增大,大气对总偏振反射的贡献越大;针对外场实验,仿真计算了不同时序同等观测条件下的线偏振度值,与实测结果相对误差在0.1范围内,一致性很好。研究结果为近地面偏振特性传输研究提供了理论支持,并为近地面偏振观测中的大气校正奠定了基础。     

空间目标光谱偏振特性

偏振特性及其变化反映了目标的状态信息。文中讨论了采用偏振探测的方法对空间目标探测的思路与可行性,介绍了空间目标偏振测量装置,给出了空间目标的光谱偏振观测结果,并测量了与实测目标相似的空间目标缩比模型的偏振特性,对实测结果与仿真实验结果进行比较分析,结果显示两者的偏振特性变化趋势符合的很好,验证了空间目标光谱偏振观测技术的有效性。研究表明,空间目标有其自身的偏振特性变化规律,偏振度由午夜时的5 ％增加到黎明前的23.8 %,其中太阳能电池板姿态对卫星的偏振特性影响尤为明显。说明了偏振观测是空间目标探测与识别的新方法。     

太阳能光伏电池组件及材料应用

太阳能光伏是一种基于以太阳能为主要能量供应的半导体电池材料,而实现能量转换。经过转换之后的太阳能,以电能的形式作用于发电工程或系统中。在光伏发电系统中,光伏组件发挥着重要的能量传输与供应功能。其主要结构是由多种电池片组成,并按照列阵的形式加以整合和排列,最终以电池板的形态展现在太阳能发电相关工程系统结构中。通过光伏组件的有效应用,不仅实现了太阳能量的转换,更实现了绿色生态电能能源的存储。     

基于长波红外的海面场景偏振特性分析与建模

针对海面场景长波红外偏振特性建模问题,文中根据表面微元双向反射分布函数BRDF,对物体表面偏振效应进行了分析,并结合红外发射效应和红外反射效应的综合作用,提出了一种长波红外偏振度计算模型.该模型有效描述了偏振度和物体自身红外发射值、红外反射值以及探测角之间的关系.利用Radtherm IR软件对海水辐射、大气辐射与舰船目标辐射进行计算,结合本文构建的偏振度计算模型,仿真了不同时间段内、不同观测角度下海面背景和舰船目标在长波波段的偏振度变化规律.通过仿真数据与实际测量数据的对比分析,结果表明两者具有较好的拟合度,验证了该模型对于海面场景偏振度计算的有效性.     

大气传输及目标反射对圆偏振光特性影响研究

主要对大气传输及目标反射对偏振光的特性影响进行研究,以蒙特卡罗方法为基础,采用斯托克斯-穆勒形式,依据Mie散射理论及偏振双向反射函数模型,追踪每个光子的偏振态变化,最后统计分析变化后偏振光的斯托克斯矢量和偏振信息。依据所建立的模型进行仿真,仿真结果表明,当能见度为23 km,距离为100 km,目标折射率为1.44+5.23i,表面粗糙度为0.1 mm时,大气传输对光偏振特性影响较小,而目标反射的影响较大,在接收端圆偏振光退偏为椭圆偏振光。     

基于复折射率的偏振模型及其应用

红外偏振成像技术近年来发展迅速,但偏振机理等方面的研究仍处于起步阶段.为深入研究红外辐射偏振特性的产生机理和影响因素,本文提出了一种基于复折射率的偏振模型.模型基于空气-光滑介质表面建立,适用于吸收性介质和非吸收性介质.偏振模型以介质的复折射率为参数,观测角为输入,可以输出红外辐射水平分量和垂直分量的反射率和发射率,也可以输出反射辐射和自发辐射单独作用时的偏振度.基于提出的模型,结合MATLAB仿真,文中分析了反射辐射和自发辐射偏振性的产生机制,以及反射辐射和自发辐射对目标偏振特性的影响.偏振模型的建立,有助于深入理解红外偏振,并为偏振探测提供理论支持.     

MATLAB软件在太阳能电池研究中的应用

简单介绍了MATLAB软件的功能特点,论述了该软件在建立光伏电池模型、分析太阳能电池的特性、光伏发电系统的设计与仿真、电能质量分析以及研制测试系统等多方面的用途,展望了仿真软件与太阳能电池技术共同发展的前景。     

PVT光伏光热系统结合地源热泵的应用性研究

基于PVT系统存在太阳能间歇性,无法保证光热转换连续进行的特点,以及存在集热后太阳能电池背板温度过高,导致电池板光伏发电效率下降的缺陷。采用地源热泵与PVT系统相结合,解决了单纯PVT系统在日照不充足情况下热量不能连续稳定供应的问题,提高了系统的热能利用率。同时系统采用定温加热、温差循环技术,有效降低了太阳能电池背板的温度,提高了太阳能电池的光伏发电效率和地源热泵的工作效率以及系统在不同工况下连续运行的可靠性和稳定性。     

国内首块车顶用光伏电池板在河北保定问世

国内第一块汽车车顶用光伏电池板日前在位于河北保定市的英利集团光伏应用技术研究院研发成功。据介绍,这种名为＂车顶用双曲面一体化成型光伏组件＂的电池板．具有自主专利技术和自主知识产权。其主要原理为：光伏电池板接收太阳能发电后储存在汽车蓄电池内,功率为180W,     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-