激光光束传输因子M~2的一些问题

本文讨论与 M2 因子有关的一些问题 ,指出在近轴近似条件下由光束的二阶强度矩定义的 M2 因子满足 M2 ≥ 1 ,其中只有对基模高斯光束等式才成立 .由光束的功率通量值定义的 M2 因子 ( M2pc)有可能小于 1 ,M2pc的大小取决于所定义的光斑半径内包含的光功率的百分数 .通过计算光场的二阶矩 ,我们获得了轴向相干叠加的高斯光束的 M2 因子的解析解     

Detection of Taurine in Biological Tissues by S NMR Spectroscopy

The potential of ³³S NMR spectroscopy for biochemical investigations on taurine (2-aminoethanesulfonic acid) is explored. It is demonstrated that ³³S NMR spectroscopy allows the selective and unequivocal identification of taurine in biological samples. ³³S NMR spectra of homogenated and intact tissues are reported for the first time, together with the spectrum of a living mollusc. Emphasis is placed on the importance of choosing appropriate signal processing methods to improve the quality of the ³³S NMR spectra of biological tissues.     

水下图像导航技术在潜艇上的应用

潜艇传统的导航方法是采用惯导、无线电导航等技术,随着计算机技术=数字图像处理技术以及传感器技术的发展,在潜艇上采用视觉图像定位测距系统进行导航是一个新的发展方向,它可以实现潜艇自主导航,减少被敌方发现和干扰的机会,从而增强潜艇的隐蔽性及其发起攻击的突然性,因此,研究图像导航技术并将其应用到实际战斗单元上是迫切需要的,水下视觉图像包括声视觉和光视觉两种图像形式,中就水下图像导航技术的几个方面阐述目前的技术现状,指出将其应用于潜艇导航的可行性。     

Quality Tolerancing and Conjugate Duality

This paper studies the relationship between product quality as defined by tolerances on the product to tolerances on the parts. All the standard sure-fit and the statistical-fit tolerancing models, which seek to find the least cost tolerances for the parts given the product specification, are found to be convex. Thus conjugate duality provides a unifying framework for studying the relationship between quality and tolerancing and the analysis and solution of such problems. Moreover this convexity is maintained even with the addition of quality loss functions. Quality loss is modeled on the basis of parts or the product. The analysis leads to an analytic solution to a number of models including the quality loss model.     

The bifurcation threshold value of the chaos detection system for a weak signal＊

Recently, it has become an important problem to confirm the bifurcation threshold value of a chaos detectionsystem for a weak signal in the fields of chaos detection. It is directly related to whether the results of chaos detectionare correct or not. In this paper, the discrimination system for the dynamic behaviour of a chaos detection system fora weak signal is established by using the theory of linear differential equation with periodic coefficients and computingthe Lyapunov exponents of the chaos detection system; and then, the movement state of the chaos detection system isdefined. The simulation experiments show that this method can exactly confirm the bifurcation threshold value of thechaos detection svstem.     

信号处理技术在重叠化学信号解析中的应用*

重叠峰解析是目前分析化学中亟须解决的一个重要问题,化学计量学用于重叠峰解析就是借助某些数学或统计学方法,把通过化学方法和仪器未能完全分离的复合量测信号分解成几个单儿组分的信号,从而从重叠谱中获取每个组分的相关信息。本文综述了几种常见信号处理技术在重叠化学信号分辨中的应用,引用文献146篇。     

A model to set measurement quality objectives and to establish measurement uncertainty expectations in analytical chemistry laboratories using ASTM proficiency test data

A model is presented that correlates historical proficiency test data as the log of interlaboratory standard deviations versus the log of analyte concentrations, independent of analyte (measurand) or matrix. Analytical chemistry laboratories can use this model to set their internal measurement quality objectives and to apply the uncertainty budget process to assign the maximum allowable variation in each major step in their bias-free measurement systems. Laboratories that are compliant with this model are able to pass future proficiency tests and demonstrate competence to laboratory clients and ISO 17025 accreditation bodies. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/ 10.1007/s007690100398-y. Received: 31 March 2001 Accepted: 11 September 2001     

Requirements vs acceptability in proficiency testing schemes and other interlaboratory comparisons

Many laboratories take part in proficiency testing schemes, external quality assessment programmes and other interlaboratory comparisons. These have many similarities but also important differences in their modus operandi and evaluation of performance of participating laboratories. This paper attempts to highlight both the similarities and differences. It also puts particular emphasis on requirements called ”target values for uncertainty” and their meaning. Received: 24 January 2001 Accepted: 25 January 2001     

Proficiency testing on the analytical control of precious metal production

Our experience of executing proficiency testing programs on the analysis of precious metals and precious metal bearing materials is summarized. Six proficiency testing programs of the ”distributed sample testing” type were carried out using samples essentially distinct from each other: (I) certified samples of fine gold and fine silver, and (II) recoverable raw (scrap and catalyst waste) containing precious metals of unknown contents. The test results were assessed using the London Bullion Market Association (LBMA) rules and by Z-criteria using the ISO/IEC Guide 43 scale. Satisfactory results were presented by all participants for the analysis of certified samples of fine gold and fine silver. The results of catalyst waste analysis agreed rather well, whereas the scrap analysis revealed an essential discrepancy in the data for some samples. The reasons for such discrepancies are discussed. Received: 9 June 2000 Accepted: 21 November 2000     

子窗口分析法用于偶氮染料GC-MS重叠峰的解析

 将子窗口因子分析法 (SWFA)应用于GC MS联用检测数据分析 ,并以两种偶氮染料 3,3′ 二氯联苯胺和 4,4′ 次甲基 双 (2 氯苯胺 )重叠图谱为例进行了解析。结果表明 ,此方法可直接进行目标组分的质谱分辨 ,得到目标组分的质谱图 ,进而得到该组分的色谱图。其结果准确、可靠。与窗口因子分析相比 ,子窗口的选择更加容易 ,人工干预少 ,解析速度快。