基于近红外高光谱成像技术的长枣含水量无损检测

利用近红外(NIR)高光谱(900~1 700nm)成像技术对灵武长枣含水量的无损检测进行了研究。通过900~1 700nm高光谱成像系统采集了128个长枣图像,对原始光谱与Savitzky-Golay平滑处理后的光谱反射率R曲线、吸收率A曲线和Kubelka-Munk函数(KM)等曲线的偏最小二乘回归(PLSR)模型进行对比分析;采用PLSR的加权β系数分别提取不同光谱参数下的特征波长,建立RPLSR、A-PLSR和KM-PLSR的长枣含水量预测模型。结果表明,采用原始光谱建立的PLSR模型优于Savitzky-Golay平滑的PLSR模型;原始光谱的特征波长建立的PLSR模型优于全波段的PLSR模型,特征波长建立的KM-PLSR模型优于R-PLSR、A-PLSR模型,决定系数(R2)和预测均方根误差(RMSEP)分别为0.793、1.828。这表明,NIR高光谱成像技术提取特征波长进行长枣水分检测是可行的,同时也为今后长枣品质在线检测提供了理论依据。     

基于高光谱成像技术的小黄瓜水分无损检测

利用近红外高光谱成像技术对小黄瓜的水分进行无损检测研究。采用多元散射校正和 Savitzky-Golay 卷积平滑对900~1700 nm波段范围内的原始光谱进行预处理,选取最优的预处理方法;运用偏最小二乘回归系数选择特征波长,建立全波段和特征波长下的偏最小二乘水分预测模型。结果表明,经过Savitzky-Golay卷积平滑处理后的光谱建模效果最好,且利用特征波长建立的小黄瓜水分校正和验证模型的相关系数和均方根误差分别为0.86,0.90 和0.111,0.156,优于全波段建立的模型。研究表明,采用高光谱成像技术对小黄瓜水分的无损检测是可行的。     

基于高光谱成像技术的土壤盐分含量检测

利用NIR高光谱仪(光谱范围900~1700nm)对土壤含 盐量进行了无损检测,对比分析不同含盐量土壤的水分变化情况、不同时间下土壤光谱曲线 的差异。结果表明,随着土壤中含盐量的增加,土壤中水分蒸发情况受到的影响程度不同, 从而使得不同含盐量土壤的反射率存在明显的规律;在此基础上,对比分析了不同预处理方 法,优选出原始光谱;利用多元线性回归(multiple linear regression,MLR)、主成分回归 (principal component regression,PCR)与偏最小二乘回归(partial least squares regre ssion,PLSR)方法对900700 nm范围的特征波长建立模型,对比分析不同建模效果,优选β系数提取的特征波长的P LSR模型,特征波长为936、1016136、 1151186273395425458535642 nm,最优模型的预测相关系数为0.949,预测均方根误差为2.914 g/kg。因此,今后可采用 不同波段对土壤含盐量进行定量分析,为今后表层土壤含盐量遥感预测奠定基础。     

基于高光谱图谱融合技术的宁夏滩羊肉嫩度检测方法研究

利用可见/近红外高光谱图谱融合技术对宁夏滩 羊肉嫩度检测进行研究。通过高光谱系统(400～1000nm)采集了128个滩羊肉图像,对原始光谱结合偏 最小二乘回归(PLSR)模型进行多种光谱预处理研究,优选出S-G卷积平滑预 处理方法,采用PLSR的加权β系数提取9个特征波长,对比分析 全波段与特征 波长下的PLSR模型;同时提取出与羊肉嫩度相关的4个图像特征参数,建立基 于图像特征的多元线性回归(MLR)模型;在此基础上,融合特征波长与表面脂肪分布图像特 征 参数建立了羊肉嫩度的PLSR模型。结果表明,采用单一光谱数据下S-G卷积平 滑预处理结合特征波长建立的PLSR模型取得了较好预测效果,基于图谱特征 变量融合的PLSR模型相比于单一光谱模型效果更佳,预测集的相关系数和预测 均方根误差(RMSEP)分别为0.89和0.73,表明本文提出的方法 进行羊肉嫩度定量检测是可行的。     

高光谱成像技术检测冷却羊肉表面细菌总数

为了对冷却羊肉表面细菌总数进行无损检测,采用不同波段范围高光谱成像系统结合多种建模方法建立预测模型,进行理论分析和实验验证。分别在400nm~110nm和900nm~1700nm波长范围内获取冷却羊肉样本的高光谱图像信息,结合偏最小二乘和人工神经网络(反向人工神经网络和径向基人工神经网络)建立预测模型。结果表明,神经网络建模效果优于偏最小二乘;其中,径向基人工神经网络模型在400nm~1100nm和900nm~1700nm波长范围内相关系数分别为0.9872和0.9988,均方根误差分别为0.8210和0.2507,预测效果最好;而900nm~1700nm波长范围为最佳建模波长。这一结果说明利用高光谱图像技术对冷却羊肉表面细菌总数进行快速无损检测是可行的。     

高光谱成像技术对牛肉水分含量及分布的快速检测

利用可见/近红外高光谱成像技术对牛肉水分含量 及分布进行快速检测。采用可见/ 近红外高光谱成像系统(400000 nm)采集150个黄牛肉样本的高光谱图像,利用ENVI软件 提取样本感兴趣区域(ROI)并计算平均光谱值;对原始光谱数据进行预处理并利用连续投 影算法(SPA)、竞争性自适应重加权算法(CARS)和无信息变量消除算法(UVE)进行特征 波长提取,建立基于不同特征波长的偏最小二乘回归(PLSR)模型,进而优选牛肉水分含量 预测的最优模型。通过蒙特卡罗交叉验证法剔除26个异常样本值;经卷积平滑(Smoothing - SG)法预处理后的原始光谱数据所建PLSR模型效果较好,其校正集决定系数(R²c)与预测集 决定系数(R²p)分别为0.817、0.850;利用CAR S、SPA、UVE法分别优选出12、27、27个特征 波长;对比基于全波段光谱与特征波段光谱所建PLSR牛肉水分预测模型的优劣,结果显示基 于CARS-PLSR法建立的牛肉水分预测模型效果最好,其R²_c 、R²p值分别为0.814、 0.750,校 正集均方根误差(RMSEC)与预测集均方根误差(RMSEP)分别为0.477、0.555;最后,利用CARS -PLSR模型计算牛肉样本每个像素点的水分含量并利用伪彩色图对牛肉样本水分分布进行可 视化分析,进而实现牛肉水分含量的快速检测及分布的可视化表达。该研究结果可为黄牛肉 水分含量的快速检测提供理论支撑。     

基于高光谱技术的长枣内外品质同时检测

采用近红外高光谱成像技术,对长枣表面轻微损伤 和果肉硬度进行无损检测。在970～ 1630nm波 长范围内对高光谱图像数据进行主成分分析(PCA),得到第3主成分图像最适合检测长枣表面 损伤。波段比(BR)算法中, 选取1387nm和1 229nm两个波段的图像进行比值运算, 采用 1455nm单波 段图像构建掩膜作用于比值图像, 最后对图像进行阈值分割和形态学变换完成损伤区域的特征提取。BR算法检测长枣轻微损 伤的准确率达 到91.5%。对反射光谱进行多元散射校正(MSC)后与长枣果肉硬度值进 行回归分析,选择相关系数较大的5个特 征波长作为BP神经网络输 入,建立果肉硬度预测模型。预测集相关系数R和均 方根误差(RMSEP)分别为0.904和15.163。研究结果表明,利用高光谱成像技术可以实现长枣内外品质同时检 测。     

基于近红外特征波长提取与最小二乘支持向量机的白芷掺滑石粉定量研究

中药掺假不仅降低疗效而且严重危害身体健康, 本文利用近红外光谱分析技术对中药白芷中掺入滑石粉的含量进 行定量分析。仪器采用自主研制的近红外光谱仪,光谱范围为900～ 1700 nm,分辨率为4nm,采集181份白芷中掺 入了 滑石粉的样本光谱以及7份白芷中掺入了滑石粉和面粉的样本光谱,进行平滑和一阶求导预 处理的基础上,比较研究了 多种不同算法的建模效果,提出了采用移动窗口法(MW)结合遗传算法(GA)进行特征波长 优选,以最小二乘支持向 量机(LS-SVM)建立定量模型的分析方法,结果表明MW-GA能有效筛选波长,提高预测精 度,还用白芷中同时掺入了 滑石粉和面粉的多成分样本对模型进行了验证。MW-GA-LS-SVM与全光谱-PLS、MW-GA- PLS、全光谱-LS-SVM比较, 其性能最佳,在极大减少建模变量的同时,模型的验证集决定系数R²=0.995,校正均方根误差RMSEC= 0.42%,预测均 方根误差RMSEP=0.48%,表明MW-GA-LS -SVM建立的模型准确度高,为近红外光谱在中药成分快速定量分析应用提供了方法依据。     

紫外可见光谱检测水体COD算法研究

应用紫外可见(ultraviolet/visible,UV/Vis)光谱技术对宜昌市环境监测站水体有机物指标化学含氧量(chemical oxygen demand,COD)进行快速检测,对采集的94份水样进行UV/Vis波段全光谱扫描,采用平滑(Savitzky-Golay smoothing,SG)、一阶导数(first-derivative,1-Der)以及二阶导数(second-derivative,2-Der)对光谱进行预处理,并结合偏最小二乘回归(PartialLeast Squares Regression,PLSR)对水样建立COD回归预测模型,并利用该回归预测模型预测水样COD浓度。实验结果表明采用SG平滑预处理后结合连续投影算法(Successive Projections Algorithm,SPA)选取全波段光谱中的特征波长得到的PLS模型预测精度最高,相关系数r=0.91882,预测均方根误差RMSEP=2.8156mg/L-1。进一步研究发现,使用SG平滑预处理得到的岭回归(Ridge Regression)模型精度(r=0.92,RMSEP=2.765 mg/L-1)高于PLS模型,且模型仅仅选取了4个特征波长变量,占238个全波段光谱变量的1.38%。说明利用平滑光谱预处理后,再建立岭回归模型,能节约时间和降低算法复杂度,能够快速准确地进行该水样样本COD浓度预测,为进一步实现水样的COD浓度快速检测奠定了基础。     

紫外可见光谱检测水体COD算法研究

应用紫外可见(ultraviolet/visible,UV/Vis)光谱技术对宜昌市环境监测站水体有机物指标化学含氧量(chemical oxygen demand,COD)进行快速检测,对采集的94份水样进行UV/Vis波段全光谱扫描,采用平滑(Savitzky-Golay smoothing,SG)、一阶导数(first-derivative,1-Der)以及二阶导数(second-derivative,2-Der)对光谱进行预处理,并结合偏最小二乘回归(Partial Least Squares Regression,PLSR)对水样建立COD回归预测模型,并利用该回归预测模型预测水样COD浓度。实验结果表明采用SG平滑预处理后结合连续投影算法(Successive Projections Algorithm,SPA)选取全波段光谱中的特征波长得到的PLS模型预测精度最高,相关系数r=0.91882,预测均方根误差RMSEP=2.8156mg/L-1。进一步研究发现,使用SG平滑预处理得到的岭回归(Ridge Regression)模型精度(r=0.92,RMSEP=2.765 mg/L-1)高于PLS模型,且模型仅仅选取了4个特征波长变量,占238个全波段光谱变量的1.38%。说明针对该水样样本,利用平滑光谱预处理后,再建立岭回归模型,能节约时间和降低算法复杂度,能够快速准确地进行水样COD浓度预测,为进一步实现水样的COD浓度快速检测奠定了基础。     

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.     

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.     

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.     

Technology innovation and process integrations for sub-100nm gate patterning

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.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

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.     

Complete approach to automatic identification and sub-pixel center location for ellipse feature

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.     

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.     

小角度扩展相关性近似算法分析

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。     

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.