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1.
大气气溶胶是气候变化与遥感定量化等的重要影响因素, 研究气溶胶光学特性具有重要意义。基于高分五号 卫星搭载的大气气溶胶多角度偏振探测仪 (Directional polarimetric camera, DPC) 过境中国区域的数据, 开展了气溶胶 光学厚度的反演研究。基于矢量辐射传输模型 6SV 计算构建气溶胶光学特性查找表, 采用 Ross-Li 地表 BRDF 模型 和半经验 NB 模型计算地表贡献, 利用标量与偏振的多角度信息和查找表方法, 反演气溶胶光学厚度。 DPC 气溶胶光 学厚度反演结果与中国区域的 AERONET 地面站点测量结果吻合性较好, 线性拟合度较高, 相关性系数大于 0.8, 验证 了算法的可靠性, 为 DPC 有效监测气溶胶的时空分布提供技术支持。  相似文献   

2.
针对GF-5卫星搭载的多角度偏振探测仪(DPC)平台上气溶胶细粒子反演算法中半经验模型不适用于城市地表偏振反射率估算的问题。基于DPC的经验正交函数方法,开展了气溶胶细粒子光学厚度反演研究。基于米散射计算气溶胶辐射贡献,采用经验正交函数方法计算地表贡献,利用多角度偏振数据以及矢量辐射传输方程,反演气溶胶细粒子光学厚度。本研究的反演结果与中分辨率成像光谱仪的气溶胶细粒子光学厚度产品分布趋势具有一致性,然后与AERONET北京、香河、香港站点的测量结果进行定量对比,相关系数为0.97、0.96、0.9,平均绝对误差为0.08、0.07、0.12,均方根误差为0.12、0.11、0.17,验证了算法的高精度与合理性。最后呈现2019年中国部分地区的气溶胶细粒子光学厚度月平均数据,并分析山东地区气溶胶细粒子光学厚度变化情况,发现6月是全年最高的时期,均值为0.7。上述结果验证了本文算法的可靠性,可为DPC有效监测气溶胶的时空分布提供技术支持  相似文献   

3.
针对高反射率地区地表反射率难以确定的难点,假设在不同年间同一天相同地物的两个不同波段的比值近似相等的前提下,借助几何光学模型理论,应用MODIS历史产品和数据,即MODIS地表反射率产品(MOD09)、历史MODIS图像第七波段的地表反射率和待反演地区的MODIS第七波段的地表反射率数据计算出待反演地区的MODIS其他波段的地表反射率,然后结合利用6S辐射传输模式计算建立的查找表,可实现待反演区域的气溶胶光学厚度的反演.以北京市区为例,应用该方法实现了北京市区的气溶胶光学厚度反演,并把反演结果与AERONET观测站的结果进行了对比,对比发现该反演方法对亮区域有效,其误差在30%以内.  相似文献   

4.
采用偏振辐射信息反演云顶高度时,为了减小由云层及地表偏振辐射特性变化带来的反演结果不确定度,使用490 nm和865 nm通道多角度偏振信息反演卷云云顶高度.理论分析大气顶偏振特征,给出490 nm与865 nm通道偏振特性差异,说明使用此两通道偏振反射率差反演云顶高度的可行性.假设卷云为一般种类混合模型(General Habit Mixture,GHM),使用倍加累加矢量辐射传输模型计算和分析大气顶490 nm和865 nm通道偏振反射率差对卷云有效粒子半径、光学厚度和云顶压强的敏感性.分析表明,当卷云光学厚度大于3时,偏振反射率差对有效粒子半径和光学厚度的变化不敏感,对云顶压强变化敏感.根据敏感性分析结果选择适当的参数构建偏振反射率差查找表,使用查找表方法反演POLDER3数据的卷云云顶高度,并与POLDER3产品和MODIS产品进行比较.结果表明,与POLDER3的官方算法相比,使用偏振反射率差查找表方法有更宽的散射角适用范围,反演结果与MODIS产品有更好的一致性.  相似文献   

5.
航空大气多角度偏振辐射计(AMPR)可以获取多角度、多波段和偏振辐射观测数据,将AMPR装载于遥感飞机对京津唐地区(工业发达、人口集中)的气溶胶进行观测,经过数据处理和反演,得到该地区的气溶胶光学厚度。反演过程中,以大气校正后的1640nm波段观测数据作为下垫面的地表偏振信息,结合查找表的方法,综合利用多角度光谱偏振辐射信息,反演得到气溶胶的光学厚度。反演结果与同步地基观测数据对比,结果表明AMPR具备观测典型区域大气气溶胶的能力。  相似文献   

6.
鉴于多角度偏振辐射数据可以有效提升大气气溶胶参数的反演精度,设计了多角度偏振探测航空实验及数据处理流程。将我国自主研制的多角度偏振成像仪DPC搭载在航空平台上,同时在地面布设太阳辐射计CE318观测站点,设计航线串联地面观测站点,开展了航空飞行实验。对实验获得的数据进行分析处理,结果表明,多角度偏振探测航空实验可获取高精度的偏振、辐射数据;使用该数据反演大气气溶胶光学厚度,反演误差小于3%,初步验证了多角度偏振成像仪可为大气气溶胶多参数反演提供有效的数据。  相似文献   

7.
基于 2005–2013 年 POLDER-3 多角度偏振观测资料, 通过最新开发的可以实现气溶胶光学特性及组分信息 同时反演的气溶胶组分卫星反演方法获得全球气溶胶综合产品, 并利用 AERONET (Aerosol Robotic Network) 全球站 点观测资料对反演获得的气溶胶光学辐射特性产品进行了综合评价分析, 讨论了气溶胶组分反演方法的适用性和 先进性。结果表明, 气溶胶组分反演方法应用于多角度偏振观测中, 不仅可以获得高精度的多个波段气溶胶光学厚 度 (AOD) 产品, 还可以获得多个波段吸收性气溶胶光学厚度 (AAOD) 以及不同波段组合下 (440/670 nm, 670/870 nm, 870/1020 nm, 440/1020 nm) Ångstrom ¨ 指数 (AE) 等气溶胶光学辐射特性产品, 并且这些气溶胶光学特性反演产品都具 有较小偏差, 表明气溶胶组分反演方法能够更好地对观测数据实现拟合, 获得更丰富更精确的气溶胶卫星反演产品, 为进一步优化算法并提供更加精确的卫星产品奠定基础。  相似文献   

8.
针对航空偏振气溶胶反演涉及的地表双向偏振辐射分布函数(BPDF)特性问题,分析了地表双向偏振反射分布物理机理,结合经典地表BPDF模型参数特点,提出了基于阴影方程和归一化植被指数的优化地表BPDF模型。利用航空辐射偏振遥感数据,验证了新模型的精度,相对于实测结果,平均相对偏差小于9.9%。与三种经典模型模拟结果相比,新模型值随不同观测角度变化时,其一致性很好。根据新模型精度,还模拟了地表偏振反射率偏差与气溶胶光学厚度反演误差的关系,发现地表偏振反射率偏差为4×10-4时,带来反演气溶胶光学厚度误差小于0.03,满足气溶胶偏振反演应用要求。  相似文献   

9.
准确获取气溶胶光学厚度对于气候变化研究和大气环境监测具有重要意义,卫星反演气溶胶光学厚度的产品较多,开展不同气溶胶光学厚度产品间的对比研究,可为用户选择适合的气溶胶光学厚度产品提供重要依据。应用地基气溶胶观测网AERONET提供的气溶胶光学厚度数据,分析了MODIS气溶胶产品对中国区域四种典型下垫面的适用性。通过对比发现:在中国区域,城郊、森林、湖泊下垫面气溶胶光学厚度反演算法中第六版本最优,城市下垫面气溶胶光学厚度反演算法中第五版本最好。研究结论可为中国区域的MODIS气溶胶产品选择提供参考。  相似文献   

10.
为解决目前城市上空气溶胶光学厚度反演中城市地表复杂与卫星分辨率较低的问题,提出一种改进的反演算法。首先利用波段修正后的MODIS(moderate resolution imaging spectroradiometer)地表反射率产品探究了城市区与非城市区在红、蓝波段地表反射率的比值统计关系,然后运用6S辐射传输模型构建查找表反演获得北京及其周边地区的AOD分布。通过AERONET(aerosolrobotic network)观测数据验证算法的反演精度,利用相对平均偏差RMB、平均绝对误差MAE、平均相对误差MRE、均方根误差RMSE和相关系数R共5个指标进行衡量,结果表明:反演结果与AERONET观测数据具有较高的一致性,5个观测站点的R都大于0.95,MAE范围为0.037~0.065,MRE范围为24.08%~39.54%,RMSE范围为0.047~0.083,RMB范围为0.86~1.452,且所有观测点对中有超过84%满足MODIS气溶胶产品的误差精度要求,说明算法对获取高分辨率城市地区的AOD具有较好的可行性。  相似文献   

11.
This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.  相似文献   

12.
We have fabricated the white organic light-emitting devices (WOLEDs) based on 4,4' -bis(2,2 -diphenyl vinyl)-1,1' - biphenyl (DPVBi) and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene (rubrene). The device structure is ITO/2T-NATA (20 nm)/NPBX (20 nm)/CBP: x%Ir(ppy)3:0.5% rubrene (8 nm)/NPBX (5 nm)/DPVBi (30 nm)/Alq(30 nm)/LiF(0.5 nm)/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris (2-phenylpyridine) iridium [Ir(ppy)3], acts as a yellow light-emitting layer, and N,N' -bis- (1-naphthyl)- N,N' -diphenyl -1, 1' -biphenyl-4,4' -diamine (NPBX) acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir (PPY)3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.  相似文献   

13.
To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.  相似文献   

14.
本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer (LDV).  相似文献   

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