New studies on scattering properties of different kinds of soot and carbon-black

New polarization and brightness curves as a function of scattering angle are studied at λ=632.8 and 543.5 nm using PROGRA2 instruments (Propriétés Optiques des Grains Astronomiques et Atmosphériques) for four different kinds of soot and for two samples of carbon-black levitating in the cloud. The soot samples are also studied on the deposited surface. Two of the soot samples are issued from incomplete combustion of Toluene liquid solvent under two different combustion conditions. Two others are issued from a solid polymer. Polymethyl Methacrylate or PMMA under two different combustion conditions. These new studies are done using new more sensitive cameras than previous ones, allowing darker agglomerates to be detected.     

Analytically derived conversion of spectral band radiance to brightness temperature

Simple analytic expressions for brightness temperature have been derived in terms of band response function spectral moments. Accuracy measures are also derived. Application of these formulas to GOES-12 Sounder thermal infrared bands produces brightness temperature residuals between −5.0 and 2.5 mK for a 150-400 K temperature range. The magnitude of residuals for the five ASTER Radiometer thermal infrared bands over the same temperature range is less than 0.22 mK.     

基于发射率模型约束的多光谱辐射真温反演法

温度测量是工业生产或科学实验中保证产品质量、降低生产成本和确保实验安全的重要因素之一。目前非接触的测温方法以辐射测温法为主,二次测量法是多光谱辐射测温中一种常用的方法。但是,二次测量法不适用于实时数据处理。针对此问题,基于多光谱亮度温度数学模型引入了发射率模型约束条件,提出了一种多光谱辐射真温快速反演法。对于非黑体,根据不同波长下的亮度温度的关系,得出当亮度温度在一个区间内是增函数或者常数函数时,发射率在该区间内是增函数;当亮度温度在一个区间内是减函数时,则发射率在该区间内满足一个关于发射率和波长的不等式。该发射率模型约束条件根据亮度温度的信息,将发射率假设值的构建由多类减少到一类,避免了不必要的发射率的构建。实验分别采用实际发射率随波长单调下降、单调上升、先下降再上升、先上升再下降和随机变化的具有代表性的五个被测目标,针对两个被测温度点进行了仿真对比分析。结果表明,与二次测量法相比,对于同一个被测目标,在相同的温度初值和相同的发射率搜索范围下,新算法在保证精度的情况下,不仅所得结果相同,而且处理速度提升了19.16%～43.45%。     

Investigation of the Limit of Detection of an Infrared Passive Remote Sensing and Scanning Imaging System for Pollution GasEI北大核心CSCD

NECL could be used to estimate the limit of detection of the infrared passive remote sensing system. It was an important indicator of the sensitivity of the system. The theoretical equation of the NECL according to the atmospheric infrared radiation transfer model showed that NECL related to NESR, the brightness temperature of background and pollution gas, and the absorption coefficient of pollution gas. The remote sensing of SF6 was done. The limit of detection of the system at the different brightness temperature of background and pollution gas could be calculated. False color image of NECL was given from the measured data. The results show that NECL decreases rapidly by increasing the difference in brightness temperature of the background and pollution gas, the value of NECL was down to 10(-2) order of magnitude when the brightness temperature difference was equal to 30 K. False color image of NECL contributes to the discrimination of the limit of detection of the system in the complex background.     

应用单波段亮度变化率获取无云干扰的卫星数据

在卫星遥感检测中,云对数据的反演带来了严重的干扰。精确地确定云区及减弱云的干扰是具有挑战性的问题。根据云的大气辐射特性给出了卫星图像亮度变化率计算公式、图像反射率的变化率计算公式和热红外波段图像亮度温度变化率的计算方法。利用单波段亮度变化率检测卫星数据中云干扰相对强度的新方法,快速、精确地获取云区位置,得到云区以外无云干扰的数据。根据各光谱波段具有不同的透射云层能力的特点,文章还给出了卫星各红外波段对云层透射能力的客观评价以及影响透射效果的因素。在此基础上利用红外波段对伪卷云透射图像数据完成了多波段数据融合。很好地恢复了可见光波段云区下面的真实数据。统计数据表明,融合后的云区图像数据与可见光波段相关性保持一致。     

Models for the Brightness Temperature of Extended Targets at MM Wave Frequency

An experimental method of establishing formulas for calculating brightness temperature of extended targets at mm wave frequency is introduced in this paper. The formulas are obtained through the statistic process of a large amount of measured data. The formulas for concrete road, asphalt road, and crushed stone are presented, which are established by this method.     

消除自由立体显示串扰的定向背光源设计

定向背光柱透镜光栅式多视点自由立体显示器的串扰和亮度均匀性问题是影响其广泛应用的主要因素之一.本文通过分析串扰产生的原因,根据偏轴光线的成像光学原理,推导出液晶显示屏光开关板列单元与柱透镜组成的偏轴光学系统的参数计算式.提出一种液晶显示屏光开关蝶形单元结构,设计了采用该蝶形单元的定向背光自由立体显示背光源模组.模拟仿真结果表明:所设计的定向背光自由立体显示背光源可消除自由立体显示的串扰;在视点平面90%观看区域的串扰度小于0.5%,光束10%峰值宽度的串扰面积比γ=0,光束90%峰值宽度比普通液晶单元结构的增大37%,改善了不同位置观看图像亮度变化大的问题.     

Removal of tarnishing and roughness of copper surface by electropolishing treatment

Tarnishing and roughness of copper surface can be removed by electropolishing treatment (EP) imparting a bright and smooth surface at suitable conditions, e.g. current density, time, temperature, and viscosity. It was carried out by using an electrolytic cell containing phosphoric acid 55% as the electrolytic solution. Both copper working electrode and lead counter electrode, and reference electrode (SCE) were connected to a Potentiostat/Galvanostat to allow an electric current to pass through the solution. Some additives such as soluble starch, ethylene glycol, and methanol were added to reduce defects formed on the copper surface during EP process. The results showed that the highest gloss value was obtained by applying electric potential 1.5 V at the passive region of polarization curve. The surface was investigated after EP treatment, where SEM and EDX showed lower roughness in case of addition of both soluble starch and ethylene glycol more than methanol. Moreover, AFM analysis showed the lowest roughness in case of soluble starch more than other additives.     

城市典型地物的热辐射特性研究

运用热红外技术监测地表温度已获得成熟的发展,城市化进程的加快使得城市热岛效应日益显现,有关城市典型地物热辐射特性的研究对于分析城市热岛现象的成因和分布具有重要意义。本文通过对保定市地面实测数据的研究发现,地物类型、观测时间和墙面朝向是影响城市典型地物热辐射亮度温度的主要因素。结果显示,地物类型的不同显著影响其亮度温度,但仍存在同谱异物现象;不同时间观测到的地物热辐射强度不同,且在很大程度上影响其在各通道上的亮温差异;不同朝向墙面的亮温也有差异,且这种差异随观测时间而改变。对城市典型地物热辐射特性的研究具有理论和实践意义,为热红外遥感监测城市热岛效应提供了依据。