Outlook邮件删除恢复技术的分析与实现

在电子邮件取证领域中,Outlook邮件的分析和提取一直是业界关注的重点,目前已有很多成熟的技术。由于PST文件自身结构的复杂,对于邮件的恢复很少有人涉及。本文主要针对PST文件中彻底删除的邮件、已损坏的PST文件及未分配簇中的PST文件片段,提出一种扫描过滤的恢复方法,并描述如何实际应用这种恢复技术。     

偏视场用三反系统消杂光设计及仿真

分析了偏视场用三反系统的杂散光特性,根据遮光罩设计的基本原则,介绍了利用计算机仿真技术进行消杂散光设计和评价的原理.系统为特殊的矩形视场,且在y方向视场偏轴,为此,设计了盒形外壁与锥形内壁相结合的外遮光罩结构,并在CAD中进行建模,采用内部挡光片为方形并且梯度排列的结构.在λ＝0.25μm,方位角为0°和90°时分别对...     

TiAl合金PST晶体变形过程与片层界面的交互作用

利用ＴＥＭ原位应变技术研究了ＰＳＴ晶体变形过程中位错，孪晶与片层界面的交互作用。发现α２／γ界面对孪生和位错滑移的强烈阻碍是ＰＳＴ晶体在硬取向下具有高屈服强度和低塑性的重要原因。     

IN-SITU OBSERVATION OF CRACK PROPAGATION IN PST CRYSTALS OF Ti-49% AlALLOY

１ＩＮＴＲＯＤＵＣＴＩＯＮγＴｉＡｌｂａｓｅａｌｏｙｈａｓｂｅｅｎｏｆｍｕｃｈｉｎｔｅｒｅｓｔａｓｓｔｒｕｃｔｕｒａｌｍａｔｅｒｉａｌｓｆｏｒｅｌｅｖａｔｅｄｔｅｍｐｅｒａｔｕｒｅａｅｒｏｓｐａｃｅａｐｐｌｉｃａｔｉｏｎｓｂｅｃａｕｓｅｏｆｉｔｓｌ...     

Analysis of paralytic shellfish toxins and their metabolites in shellfish from the North Yellow Sea of China

Samples of toxic scallop (Patinopecten yessoensis) and clam (Saxidomus purpuratus) collected on the northern coast of China from 2008 to 2009 were analysed. High-performance liquid chromatography with post-column oxidation and fluorescence detection was used to determine the profile of the main paralytic shellfish poisoning (PSP) toxins in these samples and their total toxicity. Hydrophilic interaction liquid ion chromatography with mass spectrometric detection confirmed the toxin profile and detected several metabolites in the shellfish. Results show that C1/2 toxins were the most dominant toxins in the scallop and clam samples. However, GTX1/4 and GTX2/3 were also present. M1 was the predominant metabolite in all the samples, but M3 and M5 were also identified, along with three previously unreported presumed metabolites, M6, M8 and M10. The results indicate that the biotransformation of toxins was species specific. It was concluded that the reductive enzyme in clams is more active than in scallops and that an enzyme in scallops is more apt to catalyse hydrolysis of both the sulfonate moiety at the N-sulfocabamoyl of C toxins and the 11-hydroxysulfate of C and GTX toxins to produce metabolites. This is the first report of new metabolites of PSP toxins in scallops and clams collected in China.     

IR detectors using Pb(Mg1/3Nb2/3)O3 and Pb(Sc1/2Ta1/2)O3 ceramics under DC bias

Recently, one type of thermal-type IR detector, the pyroelectric sensor, has become of great interest in commercial applications, because of its ability to operate without cooling, its constant detectivity independent of wavelength, and its low cost. The conventional pyroelectric materials are usually normal ferroelectric materials with a first and second phase transition. The working temperatures are sufficiently below the Curie temperature T_c for stable responsivity to temperature. Electric field induced-type pyroelectric sensors have also been proposed. Relaxor ferroelectric materials such as Pb(Mg_1/3Nb_2/3)O₃ (PMN) and Pb(Sc_1/2Ta_1/2)O₃ (PST), which have a glassy Curie temperature near room temperature, are used in this type of sensor. This paper describes the sensor properties of electric field induced-type pyroelectric sensors prepared by using PMN and PST ceramics as compared with the conventional type sensors. Material evaluations of PMN and PST ceramics were made to determine their dielectric and pyroelectric properties. PMN shows excellent induced pyroelectric properties for the sensors over a wide range of temperatures. On the other hand, PST seems to be inadequate for an IR detector because of a very narrow high-response temperature range. The sensors with PMN and PST ceramics show enhanced pyroelectric activities under dc bias field. The measured sensor voltage responsivities agree with the calculated values for the PMN case. The electric field induced-type infrared sensor with thick or thin film materials seems to be satisfactory as linear array IR detectors for thermal imaging, with application of a higher electric field.     

基于OLE自动化技术的PST文件解析

为直接解析客户端软件Outlook的数据文件,分析其内在编码及逻辑结构,提出一种基于OLE自动化技术的PST文件解析方法,通过启动Outlook自动化服务器,创建Outlook自动化对象,利用Outlook提供的相关接口函数直接获取文件中的邮件信息。实验结果表明,该方法能够获得良好的效果。     

Coupled Cross-correlation Neural Network Algorithm for Principal Singular Triplet Extraction of a Cross-covariance Matrix

This paper proposes a novel coupled neural network learning algorithm to extract the principal singular triplet (PST) of a cross-correlation matrix between two high-dimensional data streams. We firstly introduce a novel information criterion (NIC), in which the stationary points are singular triplet of the crosscorrelation matrix. Then, based on Newton's method, we obtain a coupled system of ordinary differential equations (ODEs) from the NIC. The ODEs have the same equilibria as the gradient of NIC, however, only the first PST of the system is stable (which is also the desired solution), and all others are (unstable) saddle points. Based on the system, we finally obtain a fast and stable algorithm for PST extraction. The proposed algorithm can solve the speed-stability problem that plagues most noncoupled learning rules. Moreover, the proposed algorithm can also be used to extract multiple PSTs effectively by using sequential method.      

α2相滑移系对全片层组织TiAl合金屈服应力影响的初步分析

基于PST晶体的微结构和γ相及α2相普通位错和孪晶滑移启动，结合细观力学方法，通过数值模拟两相中的各滑移系上的分切应力，得出PST晶体屈服应力和外加载荷与片层之间夹角θ的关系。重点分析了α2相中柱面滑移系的启动对PST晶体屈服应力大小变化的影响。α2相中柱面滑移系的启动对PST晶体小加载角方向的屈服应力有比较明显的影响。所采用的细观方法和得到的结论对进一步研究全片层TiAl合金的屈服强度有一定的参考价值。     

基于新型电力系统仿真工具的UPFC建模研究

为了建立多机电力系统中统一潮流控制器（UPFC）的稳态及动态模型，提出了一种基于新型电力系统仿真工具箱（PST）的新方法.该建模方法对UPFC的稳态模型、动态模型及其接口采用模块化设计，在UPFC稳态潮流模型中，将并联逆变器连接母线设为发电机节点、串联逆变器则设为负荷节点；在UPFC动态模型中，则采用常用的串、并电压源模型，并考虑到直流电容的动态充放电过程.时域仿真结果表明，所提建模方法在多变量控制器设计中能有效地模拟UPFC的动稳态特性， 且该方法与基于Matlab开发环境的PST仿真工具相结合，具有设计简便、易于拓展的优点.