基于3维荧光光谱测定白酒年份酒的年份

为了能够快速准确地检测白酒年份酒的年份,采用了平行因子算法和光谱相似度算法对白酒年份酒与基酒的3维荧光光谱进行分析,分别建立了高年份基酒体积分数的测定函数和年份酒年份测定函数。结果表明,高年份基酒体积分数测定误差不超过0.02,平均加标回收率为100.28%,年份测定误差小于1年;基于3维荧光光谱快速测定白酒年份酒年份的方法,解决了由于3种基酒配制年份酒的3维荧光光谱复杂性而导致的年份酒年份鉴别困难问题。该研究为多种基酒配制年份酒的年份检测问题和其中基酒体积分数的确定提供了参考。     

应用3维同步荧光光谱测定胭脂红浓度

为了测定混合色素溶液中胭脂红的浓度,采用归一化的方法对荧光光谱进行数据预处理,将处理后的光谱数据结合径向基神经网络,建立了对胭脂红含量的预测模型。结果表明,3维同步荧光光谱、普通3维荧光光谱预测结果的平均相对误差分别为2.86%,11.12%;对于混合色素溶液中单个色素浓度的测定,3维同步荧光光谱结合径向基神经网络效果较好。该研究为预测混合色素溶液中各色素浓度提供了帮助。     

用荧光特征参量分析乙酸-水溶液的结构特性

为了研究乙酸-水溶液的分子结构,采用稳态荧光光谱检测方法获得了284nm紫外光照射乙酸-水溶液的荧光光谱及其对应的激发光谱,并测得了10组不同体积分数乙酸-水溶液的荧光光谱。通过分析其激发光谱的谱线特性和荧光峰峰值荧光强度随乙酸-水溶液体积分数的变化关系,从理论上讨论了混合溶液的总吸收度、荧光光子发射以及在发射波长为334nm产生荧光光子的量子产率,进而解释了乙酸水溶液的荧光光谱特征峰。结果表明,乙酸和水溶液体积混合比为1:1和4:1时,对应的缔合物的结合常数分别为n=3和n=1。该分析结果可为进一步研究乙酸和水分子的缔合结构提供实验和理论依据。     

同步荧光结合神经网络同时测定3种抗生素

为了更快速、简便、准确地同时测定多种抗生素混合物,采用同步荧光光谱结合径向基神经网络的方法,对3种氟喹诺酮类抗生素（乳酸环丙沙星、乳酸左氧氟沙星、盐酸左氧氟沙星）的同步荧光光谱进行研究。选择3组分浓度均为1.67ng/mL的混合溶液,测量其3维同步荧光光谱;分别测量39种不同浓度的混合溶液样本的同步荧光光谱;选取其中35种作为训练组,其余4种作为预测组,将训练组样本对应的光谱数据作为输入,建立和训练径向基神经网络;在发射波长与激发波长的差Δλ=194nm条件下,利用训练好的神经网络对预测组中各组分的浓度进行预测,得到3种组分浓度预测的平均相对误差分别达到3.59%,3.47%,3.09%。结果表明,当Δλ设定为194nm时,3种抗生素的同步荧光峰差异最为明显、区分度高,该方法能实现对3种抗生素混合物中各组分的同时测定。这为多种抗生素混合物同时测定提供了一种快速、简便、准确的方法。     

结合灵敏度降维和支持向量回归的土壤元素定量分析方法

为提高土壤元素定量分析的精度，提出一种结合灵敏度降维与贝叶斯优化算法支持向量回归（BOA-SVR）的土壤元素定量分析方法。利用便携式X射线荧光（XRF）分析仪测量得到土壤的XRF光谱，采用迭代离散小波变换对光谱进行本底扣除，并将计算的各元素净峰面积作为模型输入特征。通过灵敏度分析研究了不同输入特征集合对预测精度的影响，以实现特征降维。将样本分为训练集和测试集，通过均方根误差和决定系数评价模型的预测精度，基于Cu和As元素对比了全特征输入下的BOA-SVR模型、特征降维后的BOA-SVR模型、单参数偏最小二乘法模型的预测结果。实验结果表明，特征降维后的BOA-SVR模型在Cu和As元素预测中都获得最好的预测结果。     

基于谱间预测和联合优化的高光谱压缩感知图像重构

基于高光谱图像压缩采样数据特性的分析,提出一种基于谱间预测和联合优化的压缩感知图像重构算法.首先在谱间通过线性预测去除高光谱图像观测向量的强谱间相关性,得到熵值更小的预测残差向量;然后在凸集交替投影(Projections Onto Convex Sets,POCS)的基础上提出基于最陡下降法的联合优化算法对预测残差向...     

乙酸乙酯溶液的时间分辨荧光光谱研究

为了研究模拟白酒环境中乙酸乙酯荧光衰减的影响,采用测得不同体积分数的乙酸乙酯乙醇水溶液的稳态及时间分辨荧光光谱结合量子化学计算的方法,进行了实验测量和理论分析。结果表明,乙酸乙酯的荧光峰值分别在407nm和431nm,荧光寿命均约为1.4ns;不同体积分数乙酸乙酯乙醇水溶液衰减过程中有两种荧光寿命,其中短寿命成分为乙酸乙酯,长寿命成分为乙酸乙酯和乙醇、水分子形成的多聚体结构;多聚体结构中分子间相互作用使得乙酸乙酯的平面性提高,这有利于辐射跃迁;水分子通过氢键和范德华力连接乙酸乙酯和乙醇的二聚体形成层状结构,阻碍了荧光体的运动,从而减少非辐射跃迁,使得荧光寿命延长。这一结果有助于丰富白酒中有机物的检测方法,也为研究溶剂环境对分子构象及光谱特性变化提供了一定的帮助。     

三维荧光光谱结合PARAFAC和GA对中国白酒品牌的鉴别

为了实现对中国白酒品牌的有效鉴别,在比较了不同品牌白酒三维荧光光谱特性的基础上,采用平行因子方法(PARAFAC)结合遗传算法(GA)获得训练样本和测试样本的浓度得分。同时利用支持向量机(SVM)方法建立中国白酒的鉴别模型,预测准确率为97.5%。PARAFAC分解得到的三个组分的浓度得分,在一定程度上反映了品牌之间的差异。PARAFAC与GA算法的有效结合为未知样本的鉴别提供了一种快速准确的方法。研究结果表明,PARAFAC-GASVM的鉴别模型具有更强的预测能力,该方法能够有效提取白酒的特征光谱信息,同时又大大降低了SVM输入变量的维数。研究结果为中国白酒的鉴别提供了一种新的思路。     

运用荧光光谱特征参量识别五粮液白酒

为了研究荧光光谱技术在白酒检测、识别中的应用,对五粮液和用于比对的茅台醇、高沟等一些常见白酒的荧光光谱进行了检测,得到了3维荧光光谱图,发现五粮液与其中大部分白酒的3维荧光光谱有显著不同,但与同属浓香型白酒的茅台醇有较大相似之处.为识别出五粮液,首先提取出表征白酒荧光光谱的特征参量,再借助最小二乘支持向量机对其进行分类...     

基于非负矩阵分解的多环芳烃成份识别

从重叠比较严重的混合物三维荧光光谱中恢复单一光谱信号,是光谱解析的难点。考虑到光谱内在的非负性,采用非负矩阵分解的投影梯度和交替最小二乘两种算法,并结合K均值初始化方法,来解析菲、芘、蒽3种芳烃混合物的三维荧光光谱数据,有效避免出现负数的分解结果,提取3种成份的三维荧光光谱,得到计算光谱与对应参考光谱的相似系数均大于0.970。计算结果表明,非负矩阵分解能够克服光谱重叠带来的干扰,有效提取光谱成份,从而实现对菲、芘、蒽的成份识别。其中,交替最小二乘的NMF算法更适合实时在线监测。     

用全反射法测冰醋酸和酒精的折射率

为了研究冰醋酸溶液和酒精溶液的折射率与体积分数的关系，采用全反射的方法测量了不同体积分数的冰醋酸溶液与酒精溶液的折射率，得到了溶液折射率与体积分数的关系曲线。结果表明，冰醋酸水溶液和酒精水溶液的折射率与体积分数均不存在简单的线性关系，而是呈现出类抛物线型的变化关系。开始体积分数随折射率的增大而增大，但在某一中间体积分数处折射率有一最大值，即冰醋酸在体积分数为0.90附近存在最大折射率，酒精在体积分数为0.80附近存在最大折射率。这一结果对于全面认识溶液折射率与体积分数的关系是有帮助的。     

Alignment of 3-D optical coherence tomography scans to correct eye movement using a particle filtering

Eye movement artifacts occurring during 3-D optical coherence tomography (OCT) scanning is a well-recognized problem that may adversely affect image analysis and interpretation. A particle filtering algorithm is presented in this paper to correct motion in a 3-D dataset by considering eye movement as a target tracking problem in a dynamic system. The proposed particle filtering algorithm is an independent 3-D alignment approach, which does not rely on any reference image. 3-D OCT data is considered as a dynamic system, while the location of each A-scan is represented by the state space. A particle set is used to approximate the probability density of the state in the dynamic system. The state of the system is updated frame by frame to detect A-scan movement. The proposed method was applied on both simulated data for objective evaluation and experimental data for subjective evaluation. The sensitivity and specificity of the x-movement detection were 98.85% and 99.43%, respectively, in the simulated data. For the experimental data (74 3-D OCT images), all the images were improved after z-alignment, while 81.1% images were improved after x-alignment. The proposed algorithm is an efficient way to align 3-D OCT volume data and correct the eye movement without using references.     

Motion compensated lossy-to-lossless compression of 4-D medical images using integer wavelet transforms.

This paper proposes a method for progressive lossy-to-lossless compression of four-dimensional (4-D) medical images (sequences of volumetric images over time) by using a combination of three-dimensional (3-D) integer wavelet transform (IWT) and 3-D motion compensation. A 3-D extension of the set-partitioning in hierarchical trees (SPIHT) algorithm is employed for coding the wavelet coefficients. To effectively exploit the redundancy between consecutive 3-D images, the concepts of key and residual frames from video coding is used. A fast 3-D cube matching algorithm is employed to do motion estimation. The key and the residual volumes are then coded using 3-D IWT and the modified 3-D SPIHT. The experimental results presented in this paper show that our proposed compression scheme achieves better lossy and lossless compression performance on 4-D medical images when compared with JPEG-2000 and volumetric compression based on 3-D SPIHT.     

Medical image segmentation by combining graph cuts and oriented active appearance models

In this paper, we propose a novel method based on a strategic combination of the active appearance model (AAM), live wire (LW), and graph cuts (GCs) for abdominal 3-D organ segmentation. The proposed method consists of three main parts: model building, object recognition, and delineation. In the model building part, we construct the AAM and train the LW cost function and GC parameters. In the recognition part, a novel algorithm is proposed for improving the conventional AAM matching method, which effectively combines the AAM and LW methods, resulting in the oriented AAM (OAAM). A multiobject strategy is utilized to help in object initialization. We employ a pseudo-3-D initialization strategy and segment the organs slice by slice via a multiobject OAAM method. For the object delineation part, a 3-D shape-constrained GC method is proposed. The object shape generated from the initialization step is integrated into the GC cost computation, and an iterative GC-OAAM method is used for object delineation. The proposed method was tested in segmenting the liver, kidneys, and spleen on a clinical CT data set and also on the MICCAI 2007 Grand Challenge liver data set. The results show the following: 1) The overall segmentation accuracy of true positive volume fraction TPVF > 94.3% and false positive volume fraction can be achieved; 2) the initialization performance can be improved by combining the AAM and LW; 3) the multiobject strategy greatly facilitates initialization; 4) compared with the traditional 3-D AAM method, the pseudo-3-D OAAM method achieves comparable performance while running 12 times faster; and 5) the performance of the proposed method is comparable to state-of-the-art liver segmentation algorithm. The executable version of the 3-D shape-constrained GC method with a user interface can be downloaded from http://xinjianchen.wordpress.com/research/.     

基于优先度排序的3维数据缺失快速插补法

为了快速准确地对3维光学测量的缺失数据进行插值,以利于后期对比研究,提出了基于优先度排序的3维数据缺失快速插补估算方法,并把该算法用于插补模拟实验数据以及20帧振动扬声器测试数据的验证。结果表明,与其它常用缺失数据插补方法相比,该方法运算速度快、插补效果好,有利于处理3维测量结果的多帧和大量的数据。     

工件形状对激光相变硬化温度场和应力场的影响

利用Sysweld有限元软件建立三维有限元模型,采用三维高斯热源,考虑材料热物性能随温度的变化,对平板和回转体内壁进行了激光相变硬化数值模拟。分析了温度场、残余应力以及马氏体分布的异同,研究了工件形状对激光相变硬化温度场和残余应力的影响规律。结果表明,在表层方向上,平板模型和回转体内壁模型的热循环相似;截面方向上,内壁模型峰值温度高于平板模型。处理后相变区组织均主要以马氏体为主,其体积分数约为90%。相变区边缘及热影响区产生残余拉应力,相变区存在残余压应力;与内壁模型相比,平板模型相变区中心残余压应力数值较大。     

A hybrid Yee algorithm/scalar-wave equation approach

In this paper, two alternate formulations of the Yee algorithm, namely, the finite-difference time-domain (FDTD) vector-wave algorithm and the FDTD scalar-wave algorithm are examined and compared to determine their relative merits and computational efficiency. By using the central-difference divergence relation the conventional Yee algorithm is rewritten as a hybrid Yee/FDTD scalar-wave algorithm. It is found that this can reduce the computation time for many 3-D open geometries, in particular planar structures, by approximately two times as well as reduce the computer-memory requirements by approximately one-third. Moreover, it is demonstrated both mathematically and verified by numerical simulation of a coplanar strip transmission line that this hybrid algorithm is entirely equivalent to the Yee algorithm. In addition, an alternate but mathematically equivalent reformulation of the Enquist-Majda absorbing boundary condition based on the normal field component (relative to the absorbing boundary wall) is given to increase the efficiency of the hybrid algorithm in the modeling of open region problems. Numerical results generated by the hybrid Yee/scalar-wave algorithm for the Vivaldi antenna are given and compared with published experimental work