端羟基丁腈橡胶的合成

在１０Ｌ和５０Ｌ不锈钢聚合釜中，以合成端羟基丁腈橡胶（ＨＴＢＮ）为目的，用Ｈ２Ｏ２作引发剂、乙醇作溶剂，研究了本二烯（Ｂｄ）和丙烯腈（ＡＮ）的溶液共聚合。结果表明，在ＡＮ／Ｂｄ为１０／９０，１５／８５，２０／８０，Ｈ２Ｏ２用量为４．０／８．０ｇ，乙醇用量为７０－８０克，１１０－１２０℃和１２０－１５０ｍｉｎ的聚合条件下，可以得到Ｍ。为２３００－４２００、羟值（ＫＯＨ）为４０．０－８０．０ｍｇ／ｇ、     

Singular points detection based on multi-resolution in fingerprint images

The singular points of fingerprints, namely core and delta, play an important role in fingerprint recognition and classification systems. Several traditional methods have been proposed; however, these methods cannot achieve the reliable and accurate detection of poor-quality fingerprints. In this paper, an algorithm is proposed which combines improved Poincaré index and multi-resolution analysis to detect singular points. Conventional Poincaré index method is improved on the basis of the Zero-pole Model analysis to detect singular points with different resolutions. A model is presented to extract the multi-resolution information of the fingerprint pattern; this model divides fingerprint image into nonoverlapping blocks corresponding to different block sizes on the basis of wavelet functions to compute multiple resolution directional fields, and block position shifting is performed on these resolution levels to capture the features of the ridge direction patterns, where the corresponding shifting intervals are based on Sampling theorem. The relationship of singularities detected by improved Poincaré index in different resolution directional fields is used to confirm singular points accurately and reliably. The combination of local and global information makes our algorithm more robust to noise than methods that use local information only, and the existence of this algorithm increases the insight into the nature of singular points extraction. The accuracy and reliability of the method are demonstrated by experiment on database NIST-4, public fingerprint databases FVC02 DB1 and DB2.     

多网融合承载的P2P直播覆盖网优化关键问题分析

P2P直播作为流媒体传输中IP组播的替代方案,其物理承载以IP单播为基础。而近年来P2P直播在实际使用中反映出IP单播在传输性能上的瓶颈。随着技术、产业和政策的发展,单播、组播和广播三种物理传输网逐渐融合,P2P覆盖网不但能够将多网的接入融合提升为应用融合,更应该利用多网融合的优势提高P2P直播的性能。从P2P直播网的应用情况、覆盖网与物理网的融合以及P2P直播分发模式三个方面,分析了直播覆盖网利用多网融合优势的关键问题,最后总结了目前P2P直播中存在的可改进因素,并指出了利用多网融合进行P2P直播技术优化的研究重点。     

交通标志的自动定位与识别

交通生活日益复杂,无人驾驶汽车渐渐被重视,在这样的智能交通系统中,高效准确地识别交通标志无疑是一个非常重要的课题.本文利用数字图像处理方法对各种形状的交通标志进行处理,实现自动定位与识别交通标志的目的.     

具有任意图形编码的二值位相光栅的制作

基于大规模集成电路加工技术介绍具有任意图形编码的二值位相光栅的制作过程。其中包括振幅掩模母版的制作和掩模图形的转移两部分。针对制作的25×25扇出的Dammann光栅,给出了实测结果,即:扇出点光强的均匀性偏差(以最大相对偏差来衡量)为9.7%,光栅的二维衍射效率为80.65%(除去光栅基板对光的两次反射作用),最后分析了制作误差的影响     

油田污水处理系统中人机接口电路的设计与实现

文章介绍了一种基于80 C1 96KC型单片机和可编程键盘显示接口芯片82 79接口的设计方法,提供了接口电路的结构图和键盘、显示的程序清单。最后通过Wave60 0 0仿真器对所设计的电路和程序进行了验证,实验结果表明接口电路的硬件设计合理,软件可靠,能满足油田污水处理控制系统对人机接口的要求。     

基于改进的BRNN网络的二级结构预测

针对双向反馈神经网络(BRNN)的结构复杂、收敛速度慢的特点,本文提出了一种改进的BRNN网络.将BRNN左、右子网络的隐层删除,直接将输入连接到状态层,并且采用BP改进算法中的弹性算法进行训练.以90条序列共15377个氨基酸进行交叉验证.仿真结果表明,改进网络以及采用的弹性算法可以有效地缩短网络收敛时间.     

A multi-crystal wavelength dispersive x-ray spectrometer

A multi-crystal wavelength dispersive hard x-ray spectrometer with high-energy resolution and large solid angle collection is described. The instrument is specifically designed for time-resolved applications of x-ray emission spectroscopy (XES) and x-ray Raman scattering (XRS) at X-ray Free Electron Lasers (XFEL) and synchrotron radiation facilities. It also simplifies resonant inelastic x-ray scattering (RIXS) studies of the whole 2d RIXS plane. The spectrometer is based on the Von Hamos geometry. This dispersive setup enables an XES or XRS spectrum to be measured in a single-shot mode, overcoming the scanning needs of the Rowland circle spectrometers. In conjunction with the XFEL temporal profile and high-flux, it is a powerful tool for studying the dynamics of time-dependent systems. Photo-induced processes and fast catalytic reaction kinetics, ranging from femtoseconds to milliseconds, will be resolvable in a wide array of systems circumventing radiation damage.     

Effect of tetraalkylphosphonium based ionic liquids as lubricants on the tribological performance of a steel-on-steel system

A series of asymmetrical tetraalkylphosphonium ionic liquids were synthesized and evaluated as a new kind of lubricant for the contact of steel/steel using an Optimol SRV oscillating friction and wear tester in ambient condition. The phosphonium ionic liquid shows excellent tribological performance when being used as the lubricating oil, and is superior to the conventional high temperature lubricants X-1P and perfluoropolyether (PFPE) in terms of anti-wear performance and load-carrying capacity. The chemical compositions of the boundary film generated on different contact surfaces were analyzed on a scanning electron microscope with a Kevex energy dispersive X-ray analyzer attachment (SEM/EDS) and X-ray photoelectron spectrometer (XPS). The friction–reduction and anti-wear mechanism of tetraalkylphosphonium as the lubricant were proposed to originate from the active elements P in the tetraalkylphosphonium ionic liquids reacting with the fresh surface to form a reaction film onto specimen surface, an extreme-pressure film with lower shearing strength, which leads to lower friction coefficient, and good wear resistance.