一种快速有效的捷联系统初始对准算法

在捷联惯性系统中，初始对准是影响系统输出精度的最重要环节，陀螺漂移是引起对准误差的主要原因。本文在对捷联系统误差进行分析的基础上，结合卡尔曼滤波器的滤波特性，提出一种把陀螺随机常值漂移标定与初始对准进行多级组合的卡尔曼滤波方法。     

PLIF技术测量浓度场及其二维数字校正

推导了ＰＬＩＦ技术测量浓度场时液地内荧光强度的分布，提出了ＰＬＩＦ技术的二维数字校正方程和校正方法来消除激光片光的高斯分布和沿光程衰减的影响．在此基础上，对圆形紊动射流的浓度场进行了测量和校正．此外，还将测量结果与前人的半经验理论进行了分析和比较。     

基于机器视觉的移动工件抓取和装配的研究

针对工业生产线上某产品上下盖自动装配的问题,运用运动控制理论与机器视觉相结合,搭建了一套模拟工业生产线产品装配系统。首先利用工业相机对进入视场的工件进行单帧图像采集,获取图像数据;然后利用OpenCV对数字图像进行处理,包括中值滤波、阈值分割、孔洞填充、边缘提取来获取数字图像的特征;之后通过质心法结合矩形拟合计算出工件的质心坐标和偏转角度;最后引导六轴机械臂抓取产品的时候能根据图像处理结果进行纠偏和补偿。该系统采用平面棋盘格标定板对工业相机进行了标定,并且在线进行了验证,实验结果表明,工件抓取和装配成功率为100%,满足工业现场的装配精度要求。     

KDP晶体相位匹配角理论预测模型及其验证分析

在高功率固体激光器的终端光学组件内, 大口径薄型KDP (KH₂PO₄)晶体的精密装配和校准是实现惯性约束核聚变的关键技术之一. 为了达到晶体在线安装高效高精度的要求, 需要测量高功率激光三次谐波转换效率达到最高时的晶体相位匹配角分布. 本文针对Ⅰ/Ⅱ类大口径薄型KDP晶体三次谐波转换的方式, 根据晶体的非线性光学属性获得了晶体不同位置相位匹配角之间的关系; 根据激光束在晶体内的传输路径分析得到了晶体面形、相位匹配角与激光三次谐波转换效率达到最高时 晶体最佳偏转角之间的相互关系. 在此基础上, 建立了Ⅰ/Ⅱ类KDP晶体相位匹配角的理论预测模型, 并利用实验进行了验证和分析. 实验结果表明, 晶体相位匹配角的预测值与实验值之差在10.0 μrad以内, 验证了Ⅰ/Ⅱ类KDP晶体相位匹配角理论预测模型的正确性, 为获得晶体全口径相位匹配角分布提供了简单、高效的预测方法.     

制冷型红外成像系统内部杂散辐射测量方法

杂散辐射是红外光学系统设计和检测过程中涉及的一项重要指标.为了定量测量红外成像系统内部杂散辐射, 提出一种基于辐射定标的测量方法, 并通过理论推导和实验验证以说明该方法的合理性.首先, 建立了不带光学系统的辐射定标模型, 即探测器直接接收定标源辐射能, 获得探测器内部因素对系统输出的影响; 然后将其与带有光学系统的定标结果进行比较, 得到由光学系统自身辐射对系统输出的影响, 进而计算红外成像系统内部杂散辐射; 最后通过实验证明了本文理论的正确性.该方法操作简单, 对实验条件要求低, 并可以精确地测量红外成像系统内部杂散辐射.可用于指导红外系统设计中的杂散辐射抑制, 验证系统杂散辐射分析结果是否准确以及检测系统杂散辐射指标是否合格.     

Second-order and higher-order multivariate calibration methods applied to non-multilinear data using different algorithms

We discuss and evaluate the current state of second-order and higher-order multivariate calibration methods devoted to the determination of compounds in non-multilinear data systems. We examine possible causes of multilinearity deviations:

(1)

a non-linear relationship between signal and analyte concentration;

(2)

a signal for a given sample that is non-multilinear; and,

(3)

component profiles that are not constant across the different samples.

We discuss the advantages and the limitations of the algorithms available to cope with these different situations.The review covers relevant analytical problems found in samples of environmental and biological interest, highlighting some significant examples, and evaluating the advantages and the limitations of the different algorithms available.     

NIR analysis of pharmaceutical samples without reference data: improving the calibration

Using an appropriate set of samples to construct the calibration set is crucial with a view to ensuring accurate multivariate calibration of NIR spectroscopic data. In this work, we developed and optimized a new methodology for incorporating physical variability in pharmaceutical production based on the NIR spectrum for the process. Such a spectrum contains the spectral changes caused by each treatment applied to the component mixture during the production process. The proposed methodology involves adding a set of process spectra (viz. difference spectra between those for production tablets and a laboratory mixture of identical nominal composition) to the set of laboratory samples, which span the wanted concentration range, in order to construct a calibration set incorporating all physical changes undergone by the samples in each step of the production process. The best calibration model among those tested was selected by establishing the influence of spectral pretreatments used to obtain the process spectrum and construct the calibration models, and also by determining the multiplying factor m to be applied to the process spectra in order to ensure incorporation of all variability sources into the calibration model. The specific samples to be included in the calibration set were selected by principal component analysis (PCA). To this end, the new methodology for constructing calibration sets for determining the Active Principle Ingredients (API) and excipients was applied to Irbesartan tablets and validated by application to the API and excipients of paracetamol tablets. The proposed methodology provides simple, robust calibration models for determining the different components of a pharmaceutical formulation.     

Quantitative analysis by comprehensive two-dimensional gas chromatography using interval Multi-way Partial Least Squares calibration

A new approach for target quantitative analysis for comprehensive two-dimensional gas chromatography (GC × GC), interval Multi-way Partial Least Square (iNPLS) is presented and evaluated in this paper. In iNPLS, the two-dimensional chromatogram is split in small sections; each of these pieces is treated as an independent new chromatogram. Separated conventional NPLS calibration models for the concentration of the target analyte are built for each of the pieces of the whole chromatogram, and the best model is selected for quantitative analysis. An algorithm for iNPLS running on MatLab platform was written, preliminarily evaluated with using solutions of model compounds with different chemical properties and subsequently applied to quantify some allergens in perfume samples. The results were found to be adequate, and good precision and accuracy was obtained even for poorly resolved peaks.     

液相色谱-三重串联四极杆质谱测定粮油中的黄曲霉毒素

建立了超声提取-液相色谱-电喷雾三重串联四极杆质谱测定玉米、大米、大豆等粮油固体样品中黄曲霉毒素B1、B2、G1和G2(AFB1、AFB2、AFG1和AFG2)的方法。分析前对样品进行超声提取,优化得到最佳超声提取条件: 溶剂为甲醇-水(含40 g/L NaCl) (80:20, v/v)溶液、料液比为1:3(g:mL)、温度为50 ℃、时间为3 min。然后对提取的样品进行免疫亲和特异性净化。最后与液相色谱-电喷雾三重串联四极杆质谱联用,使用C18反相色谱柱,流动相为甲醇-10 mmol/L乙酸铵水溶液梯度洗脱,以黄曲霉毒素M1(AFM1)作为内标进行定量测定。结果表明,AFB1、AFB2、AFG1和AFG2的检出限分别为0.002、0.004、0.004和0.012 μg/kg。方法的加标回收率为87%～111%,日内相对标准偏差(RSD)和日间RSD分别不大于6.7%和5.6%。实验结果表明该方法可以有效地降低基质效应的影响,相比于外标法能极大地提高方法的准确度。     

对直接标准化算法的改进及其应用

由于各种仪器之间存在差异,主机上建立的定量模型用于从机会导致预测结果出现较大偏差。目前主要通过有标样方法和无标样方法来减小预测偏差。该文对现有标样方法中的直接标准化算法进行改进,在转移矩阵的建立过程中,对从仪器数据矩阵进行主成分分解,以预测均方差为判定标准,确定最终的转移矩阵。并以玉米和烟草数据为对象,测试了该法的有效性。玉米样品含有2种成分:水分和蛋白质;烟草样品含有4种成分:还原糖、总糖、总氮和总碱。结果表明,对于玉米样品中的2种成分,采用改进的方法可显著提高预测的准确度;对于烟草中的4种成分而言,采用改进的方法可获得稳健的预测结果。