BP神经网络电子束扫描均匀度校正系统

 电子束的扫描均匀度是工业辐照电子直线加速器的重要技术指标，该校正系统利用人工神经网络中的误差反向传播法可以对扫描电流波形进行校正，以克服扫描磁场引起的电子束形状变化、位置改变等造成的电子束分布的不均匀性，从而使扫描曲线的归一化均方偏差达到1.8%。     

Study on Deformation of Polycrystalline Aluminum Alloy Using Moiré Interferometry

Polycrystalline aluminum alloy is manufactured by annealing, compared to the width of the specimen, the size of the grains can not be omitted, which makes the specimen anisotropic. Under uniaxial tension, the deformation field is inhomogeneous. In this study, moiré interferometry is successfully applied to measure the deformation of the polycrystalline specimen. The experimental results presented the stress versus strain responses of the marked grains in different orientations and different shapes. By using fringe centering method, the strain distributions under certain load in the centers and on the boundaries of the grains are analyzed.     

Interfacial bonding mechanism and bonding strength of AlTiCrN coating by cathodic arc ion plating

AlTiCrN coating was prepared on the surface of YT14 tungsten carbide cutting tools by cathodic arc ion plating with Ti, Al and Cr as targets. The surface morphologies, interface energy spectrum, phase and elements' binding energy of the coatings were observed with SEM, EDS, XRD and XPS, respectively, and bonding strength of the coating interface was measured with scratch tester. The results show that the phases of AlTiCrN coating are mainly composed of AlN, CrN and TiN, the crystal plane of (111) has a strong preferred orientation. The concentrations of Al, Ti, Cr, N in the coating are higher than those in the substrate, showing the gradient diffusion distribution at the bonding interface, while C atoms of the substrate have diffused into the lattices of TiN, AlN and CrN to form an obvious interdiffusion layer, and the average bonding strength of coating interface is 57.65 N. Copyright © 2014 John Wiley & Sons, Ltd.     

Tutorial review on validation of liquid chromatography–mass spectrometry methods: Part I

This is the part I of a tutorial review intending to give an overview of the state of the art of method validation in liquid chromatography mass spectrometry (LC–MS) and discuss specific issues that arise with MS (and MS/MS) detection in LC (as opposed to the “conventional” detectors). The Part I briefly introduces the principles of operation of LC–MS (emphasizing the aspects important from the validation point of view, in particular the ionization process and ionization suppression/enhancement); reviews the main validation guideline documents and discusses in detail the following performance parameters: selectivity/specificity/identity, ruggedness/robustness, limit of detection, limit of quantification, decision limit and detection capability. With every method performance characteristic its essence and terminology are addressed, the current status of treating it is reviewed and recommendations are given, how to determine it, specifically in the case of LC–MS methods.     

单轴条件下砂岩三维破裂过程的CT观测

岩石破裂过程研究一直是岩石力学专家关注的重要问题。本文采用特制的三轴压力仪与医用西门子SOMATOM -plusCT扫描仪结合 ,对砂岩进行了室内单轴压缩试验。通过对砂岩的CT图像和密度损伤增量与应力关系曲线分析 ,结果显示 ,砂岩的破裂演化过程可分为初始损伤的压密、裂纹出现—扩展、裂纹归并—分岔、裂纹重分岔—扩展以及裂纹惯通—宏观破坏等五个阶段。在初始损伤的压密阶段 ,砂岩的密度损伤增量为正值 ,速率也为正 ;在裂纹出现—扩展阶段 ,砂岩出现局部密度损伤增量减小 ,并随应力增加而由正值转为负值 ,速率也由正变负 ;在裂纹归并—分岔阶段 ,砂岩的密度损伤增量全为负值 ,速率也变快 ;在裂纹重分岔—扩展阶段 ,砂岩的密度损伤增量继续变负 ,但速率变慢 ;在裂纹惯通—宏观破坏阶段 ,砂岩的密度损伤增量继续变负 ,速率变的更快。     

一种新型非晶态分子材料的非线性光学折射率和吸收特性

用单光束扫描法测量了在532nm处一种新型非晶态分子材料5,5′Bis(dimesitylboryl)2,2′bithiophene的非线性折射率和吸收系数样品非线性透射特性的分析表明,在靠近线性吸收区的532nm处有饱和吸收存在由三能级饱和模型和Zscan法确定了饱和强度、非线性折射率的实部和虚部研究结果表明:这种新型非晶态分子材料具有非常好的光子学应用前景.     

双调制步进扫描红外光谱技术用于聚氨酯薄膜动态拉伸实验

将步进扫描多调制傅里叶红外光谱技术用于聚氨酯薄膜动态拉伸的流变光谱性质研究。讨论了步进扫描干涉仪的工作原理、包括相调制在内的多调制频率与数字采集实验设置及数字信号处理方法。得到聚氨酯薄膜在100Hz频率、1.0λ振幅的相调制作用下，相对于5Hz拉伸频率的同相位（In-phase)和正交相位（Quadrature)的红外吸收光谱。     

Holographic optical elements as scanning lidar telescopes

We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. Rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed transmission and reflection HOEs for use at the first three harmonic wavelengths of Nd:YAG lasers. The diffraction efficiency, diffraction angle, focal length, focal spot size and optical losses were measured for several HOEs and holographic gratings, and found to be suitable for use as lidar receiver telescopes, and in many cases could also serve as the final collimating and beam steering optic for the laser transmitter. Two lidar systems based on this technology have been designed, built, and successfully tested in atmospheric science applications. This technology will enable future spaceborne lidar missions by significantly lowering the size, weight, power requirement and cost of a large aperture, narrow field of view scanning telescope.     

有限线状连续带电体二维平面电场的计算机模拟

利用切线法和扫描法绘制一些有限线状连续带电体所在平面的电力线和等势线。     

使用多个线阵CCD-计算机系统实时监控多界面位置

本文提出一套多界面位置实时监控系统。该系统采用八个线阵ＣＣＤ像感器分别接收每个界面的光学图像。按照控制程序的设定，适时点亮界面的照明光源，同时驱动ＣＣＤ开始工作，并在采集完界面位置信息后，关掉照明光源及ＣＣＤ，以延长系统的寿命，实现长期连续工作。为了同时分别监控多个界面，设计了专用微机接口电路，通过硬件电路实现各界面数据的同时锁存，然后将每个ＣＣＤ的光电信号采入计算机，解决了目视读数无法保证多处数据在时间上一致性的困扰。运用该系统监控多处油水界面，每处均可在１００ｍＬ体积的检测管内测量到０．１ｍＬ的界面变化。