脉冲离散效应对光纤中基于交叉相位调制的脉冲压缩的影响

通过数值模拟，分析了脉冲离散效应对单模光纤正群速色区基于暗孤子交叉不相位调制的脉冲压缩的影响，并提出了减轻这种影响的办法，作者发现，即使暗孤子与被压缩脉冲的中心波长相差很小，离散效应对脉冲压缩的影响也很大，离散效应不仅导致脉冲压缩比的减小和压缩后脉冲峰值功率的降低，而且还导致脉冲压缩所需最佳光纤长度的增加以及压缩后的脉冲呈现不对称性，还发现，若采取本文提出了的非同步耦合法，则可以明显地弥补离散效应     

钢卷尺刻度在线测量系

本文介绍了一种钢卷尺刻度在线测量系统 ,它采用了高速摄像及计算机数据处理技术 ,文章阐述了系统的非接触动态测量原理 ,描述了光电信号的处理方法 .     

全息散斑条纹的提取及图像处理

介绍了一种新的全息散斑条纹的提取方法.理论和实验表明:对全息散斑底片逐点再现时,两伴生亮斑条纹是全息散斑底片一级衍射光的杨氏干涉条纹,与中央的杨氏条纹是一致的,有较高的条纹对比度且没有背景光晕的影响.利用计算机数字图像处理技术对伴生散斑条纹进行处理,定量测试了受静载物体的面内位移.     

成像光谱技术中机上实时数据压缩方法研究

根据成像光谱仪的特点用一系列串行的一维压缩实现二维图像压缩.提出了在机上对原始数据从光谱方向进行实时压缩的“二真值线性预测方法”.该法可做到压缩/复原后光谱特征信息不丢失.实验表明,对大多数光谱数据在1%的重建精度下,至少可获得2:1的压缩比.从总体而言,压缩后原始数据率可降低3～4倍.文中还对压缩数据的编码和误差进行了讨论.     

高分辨阿达玛变换显微荧光图像分析(Ⅱ)单细胞DNA荧光图像生成、处理及自动定量分析研究

本研究把荧光显微镜，阿达玛变换多通道成像技术和计算机图象处理技术结合起来，建立了一种单细胞DNA荧光图像自动定量分析系统，对系统的成像原理、信号编码和解码方法及单细胞定量分析方法进行了讨论，分析结果表明，本系统提供的单细胞定量分析数据稳定可靠。     

电子自旋共振准三维图象的重建方法

根据投影切片原理, 设计了一个简单而有效的ESR图象重建算法和程序, 可利用样品的一集ESR谱, 方便地绘制出样品在某截面的自旋密度立体轮廓图、等值图和散点密度分布图等, 为分析和研究自旋密度的分布及其性质, 提供了直观依据。作为应用, 文中给出了石英杜瓦受紫外光辐照后产生的局部晶格缺陷——F心的空间分布图, 图中清楚表明, F心的浓度与辐照方向和辐照强度的密切关系, 与试验结果完全相符。     

Multivariate calibration of near infrared spectra by orthogonal WAVElet correction using a genetic algorithm

Orthogonal WAVElet correction (OWAVEC) is a pre-processing method aimed at simultaneously accomplishing two essential needs in multivariate calibration, signal correction and data compression, by combining the application of an orthogonal signal correction algorithm to remove information unrelated to a certain response with the great potential that wavelet analysis has shown for signal processing. In the previous version of the OWAVEC method, once the wavelet coefficients matrix had been computed from NIR spectra and deflated from irrelevant information in the orthogonalization step, effective data compression was achieved by selecting those largest correlation/variance wavelet coefficients serving as the basis for the development of a reliable regression model. This paper presents an evolution of the OWAVEC method, maintaining the first two stages in its application procedure (wavelet signal decomposition and direct orthogonalization) intact but incorporating genetic algorithms as a wavelet coefficients selection method to perform data compression and to improve the quality of the regression models developed later. Several specific applications dealing with diverse NIR regression problems are analyzed to evaluate the actual performance of the new OWAVEC method. Results provided by OWAVEC are also compared with those obtained with original data and with other orthogonal signal correction methods.     

Electron microscope study of viscoelastic cationic surfactant systems

Some cationic surfactants such as cetyltrimethylammonium bromide (CTAB) show a very spectacular viscoelasticity in solution, in even very diluted states, with some aromatic substances added, such as salicylic acid. Formerly, the authors established that the remarkable solution behaviour was the result of the entanglement of such enormously elongated giant micelles, based on recognition of the existence of large aggregates, through direct observation of them as substantial images under the electron microscope.In this report, we further confirm the relation between micelle length and solution viscoelasticity after arbitrarily obtaining different size aggregates by altering the media pH, or by admixing shorter chain length surfactants than CTAB, which alone did not induce viscoelasticity.     

Changes in the physicochemical properties of transferrin upon chemical derivatization with ceramides

The interaction of native and derivatized transferrin with lecithin, cholesterol and their mixtures was studied using monomolecular layers of phospholipids. Moreover, the thermodynamic parameters corresponding to these interactions: the mixing excess free energy, interaction energy, and interaction parameter were also calculated.The ability of these two proteins to insert into monolayers was studied working at constant area.The formation of aggregates or secondary structures in solution was determined by the fluorescence and polarization values of ANS (anilinonaphthalene sulfonate), measured at different protein/ANS relationships.Abbreviations TF Transferrin - DTF derivatized transferrin - PC lecithin - CHOL cholesterol - CER ceramides - ANS anilinonaphthalene sulfonate - TNBS trinitro benzenesulfonate method     

Characterisation of the Kratos Axis Ultra with spherical mirror analyser for XPS imaging

The imaging performance of an XPS instrument employing a spherical mirror electron energy analyser has been characterised by measuring the peak position, full width at half maximum (FWHM), and lineshape, at every pixel in the image, for different modes of operation. Changes in these parameters have been identified and recommendations made for quantification of, and chemical state determination from, spectrum image data sets. Copyright © 2006 John Wiley & Sons, Ltd.