Development of calibration models for quality control in the production of ethylene/propylene copolymers by FTIR spectroscopy,multivariate statistical tools,and artificial neural networks

Principal component regression (PCR), partial least squares (PLS), StepWise ordinary least squares regression (OLS), and back‐propagation artificial neural network (BP‐ANN) are applied here for the determination of the propylene concentration of a set of 83 production samples of ethylene–propylene copolymers from their infrared spectra. The set of available samples was split into (a) a training set, for models calculation; (b) a test set, for selecting the correct number of latent variables in PCR and PLS and the end point of the training phase of BP‐ANN; (c) a production set, for evaluating the predictive ability of the models. The predictive ability of the models is thus evaluated by genuine predictions. The model obtained by StepWise OLS turned out to be the best one, both in fitting and prediction. The study of the breakdown number of samples to be included in the training set showed that at least 52 experiments are necessary to build a reliable and predictive calibration model. It can be concluded that FTIR spectroscopy and OLS can be properly employed for monitoring the synthesis or the final product of ethylene–propylene copolymers, by predicting the concentration of propylene directly along the process line. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Investigation of the Correlation between Texture and Microstructure on a Submicrometer Scale in the TEM

In recent years the investigation of local texture and microstructure by analysis of electron backscatter diffraction patterns (EBSP) in the SEM has become a very powerful and popular method. With the introduction of SEM with field emission guns (FEG) the spatial resolution of EBSP measurements could be enhanced from 500 nm with a tungsten emitter to better than 50 nm. This evolution of SEM techniques raises the question whether transmission electron microscopy (TEM) still has fields of application in texture research. The present article answers this question with a clear “yes” and presents three examples of investigations where TEM is indispensable. The three examples comprise the investigation of the correlation between dislocation structure and deformation texture, a study on nucleation mechanisms of recrystallization in highly deformed metals and the investigation of microtexture and microstructure in nanocrystalline materials. Together with the presentation of these cases some of the necessary measurement techniques are described briefly. It is shown that TEM has to be applied when highest spatial resolution of orientation determination and imaging and high accuracy of orientation determination are to be reached, when the three‐dimensional and quantitative characterization of lattice defects is required or when materials with a high density of lattice defects are to be investigated.     

带吊车门式刚架轻型钢结构厂房的设计与分析

以实际工程为背景，采用门式刚架轻型房屋钢结构设计规程，对带吊车门式刚架、吊车梁、抗风柱及基础的受力特点、设计方法进行分析，解决了设计中所遇到的问题。     

奥宇钢框胶合板模板开发与工程应用

介绍了北京奥宇模板有限公司开发的钢框木胶合板模板的技术特点,并对该模板体系在国家体育场工程和哈萨克斯坦国MAG工程中的应用情况进行了简要介绍。     

Assessment of factors considered to be important in handling tasks by expert handlers

Twenty-eight experienced handlers, considered the best in two transport companies, were interviewed using a questionnaire consisting of partially closed-ended questions. They had to assess 20 videotape handling sequences showing two different handling methods to determine, for 10 factors and overall, which one was the best. They were asked about the inportance of these factors in their choices of the best method. The aims of the study were to verify whether there was a consensus among experienced handlers as to what was a good handling method and to identify the factors taken into consideration by them. Results show the lack of consensus on the best methods. Handlers favor different strategies depending on the worjk context and their own priorities.     

基于公共存储器进行数据交换的高速数字图象处理系统

本文介绍了一种基于公共存储器进行数据交换的高速数字图象处理系统．给出了公共存储器的设计，描述了处理器对公共存储器的进程同步控制．     

微型集散系统通用过程控制软件包

本文给出一种新的基于ＭＣＳ－５１单片机集散系统通用过程控制软件包的设计原理及其实施方法。文中重点地阐述了微型集散系统的构在民，通用过程控制软件的自动生成，主要数据结构与程序结构，实现方法及关键技术等。本软件包是采用ＴＵＲＢＯＣ２．０版本和ＭＣＳ－５１泄编语言编程的，并通过了ＭＣＳ－５１组合软件的编译，形成了可用的目标码程序系统。     

基于非接触监测的隧洞反演分析可行性探讨

本文根据全站仪非接触测量原理，分析了隧洞测点位移量测的三维误差计算式。随后对全站仪位移量测的误差精度进行了分析，得到了满足反演计算要求的量测误差判别式，并提出全站仪位移量测的可行性判别方法。最后通过算例给出了判定实际工程反演分析可行的设站及仪器的优选方式。分析结果认为目前全站仪的测量精度还只适用于洞室断面较大、总位移量较大的情况，对洞室反演计算的普遍适用还有一定距离。     

高坝流激振动响应的反分析方法

为分析高速水流诱发高坝泄流结构的振动问题，根据结构动力学、随机振动理论和最优方法的基本理论，提出了基于谱分析及遗传算法的振源反分析方法，采用本文方法，可以由少量测点的动位移实测值反馈分析出各激振源等效荷载谱，通过流激振动响应的正分析方法得到整个结构在水流动力荷载作用下的动力响应，对水工结构的流激振动进行正确全面的评估，为结构损伤动态监测和诊断提供新的技术手段。并通过拉西瓦拱坝泄洪水弹性模型试验实测值与反分析计算值的比较验证了本文方法的合理性。     

Efficient Reflectance and Visibility Approximations for Environment Map Rendering

We present a technique for approximating isotropic BRDFs and precomputed self-occlusion that enables accurate and efficient prefiltered environment map rendering. Our approach uses a nonlinear approximation of the BRDF as a weighted sum of isotropic Gaussian functions. Our representation requires a minimal amount of storage, can accurately represent BRDFs of arbitrary sharpness, and is above all, efficient to render. We precompute visibility due to self-occlusion and store a low-frequency approximation suitable for glossy reflections. We demonstrate our method by fitting our representation to measured BRDF data, yielding high visual quality at real-time frame rates.