基于数字照相的砂土剪切变形模式的试验研究

利用自行研制的数字照相量测软件包Photolnfor和自行设计的大型剪切试验装置，在不同围压下，对砂土的剪切变形模式以及土体变形局部化的发生、发展和演变过程进行了全面观测．结果表明：砂土变形区域呈纺锤型，由多条曲线形大变形带和带间小变形区组成，不同围压下的剪切变形模式基本相近；土体最终形成的剪切带与初期发生的局部变形带并不完全重合；土体剪切变形可分为初期全域快速弹性变形、中期局部区域塑性变形与后期剪切带内集中塑性变形三个阶段．     

高等教育大众化背景下的大学英语教学改革

大学英语教学是大学课程的重要组成部分。而当前英语教学的质量和效果还不能满足社会对人才培养的需求,我们要抓住高等教育大发展的机遇,进一步转变思想观念,提高教师队伍的素质,推进现代教学方法,运用新的教学技术和手段,改革课程体系和教学模式,强化学生英语应用能力的培养,建立全新的大学英语教学体系。     

论自动解除危险状态行为

刑法理论的通说认为自动解除危险状态行为成立犯罪既遂，然而近年来一些学者撰文对通说提出批判，认为该行为成立犯罪中止。本文在列举各种新观点的基础上，对其逐一进行评述，指出上述观点在理论上存在不能自圆其说之处，从而最终得出通说理论仍具有合理性的结论。     

基于模式矩阵的FP-growth改进算法

数据挖掘中关联挖掘算法比较典型的有Apriori和FP—growth算法．实验和研究证明FP—growth算法优于Apriori算法．但是针对大型数据库这两种算法都存在着较大缺陷，不仅要两次或多次扫描数据库，而且很难处理支持度和数据变化等关联规则更新问题．作者提出了基于模式矩阵的FP—growth改进算法，它至多扫描数据库一次，特别在更新问题上不用重新扫描数据库．通过实验结果分析，验证了这种改进算法相对于原有FP—growth算法的优势，特别在大数据集下，大大降低了挖掘的时间复杂度．     

一种改进的多模式匹配算法

在基于有限状态自动机的多模式匹配算法(DFSA算法)基础上,结合Tuned BM算法的优点,提出一种快速的多模式字符串匹配算法,实现了多模式匹配过程中不匹配字符的连续跳跃.在一般情况下,算法不需要匹配目标串中的每个字符,而是在实际比较之前跳过尽可能多的字符,以减少字符比较的操作,实现快速匹配.在模式串较长和较短的情况下,算法都有很好的性能.分析指出算法实际比较的字符数随着模式串长度的增加而下降,并随模式集的增大有所增多.实验表明,在模式串较短时,算法需要的匹配时间仅为AC算法的50%到33.3%,AQR算法的90%左右;在模式串较长时,所需时间为AC算法的25%至12.5%,AQR算法的75%左右.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Application of fiber interferometer in coherent Doppler lidar

A novel coherent Doppler lidar (CDL) system based on single-mode fiber (SMF) components and instruments is presented to measure the speed of target. A fiber interferometer used in CDL system is reported.This fiber mixer is employed as a coherent receiver to resolve the shifts of signal-to-noise ratio (SNR) and mixing efficiency induced by backscattered field's wavefront error. For a certain wavelength, the maximum coupling efficiency between signal and SMF is determined by the ratio of pupil diameter to focal length of the coupling lens. The legible interference patterns and spectrum signals show that fiber interferometer is suitable to compensate for amplitude and phase vibrations. This robust coherent receiver can achieve improved CDL system performance with less transmitter power.     

810-nm InGaA1As/A1GaAs double quantum well semiconductor lasers with asymmetric waveguide structures

The 810-nm InGaA1As/A1GaAs double quantum well (QW) semiconductor lasers with asymmetric waveguide structures, grown by molecular beam epitaxy, show high quantum efficiency and high-power conversion efficiency at continuous-wave (CW) power output. The threshold current density and slope efficiency of the device are 180 A/cm2 and 1.3 W/A, respectively. The internal loss and the internal quantum efficiency are 1.7 cm-1 and 93%, respectively. The 70% maximum power conversion efficiency is achieved with narrow far-field patterns.     

Structural study and magnetoresistance effect of epitaxial La0.67Sr0.33MnO3–δ and Pr0.7Ca0.3MnO3−δ multilayer films

La_0.67Sr_0.33MnO_3−δ (LSMO) and Pr_0.7Ca_0.3MnO_3−δ (PCMO) multilayer epitaxial films, which were fabricated with different LSMO and PCMO layer thickness on LaAlO₃ single crystal substrates of (0 0 1) orientation by a direct current magnetron sputtering technique, were studied further, after the structure, magnetoresistance effect and magnetic properties of LSMO/PCMO/LSMO (LPL) trilayer epitaxial films were systemically studied. The superlattice structures of multilayer films were observed according to the diffraction peaks of X-ray diffraction patterns at small angles. The metal–insulator transition temperature (T_P) and peak resistivity (ρ_max) obviously changed when we altered the thickness of PCMO middle layer and the intra-field related with the thickness of those layers and their interaction. Considering the effect of the distribution of electrical field and current, and the interaction among the layers of LSMO and PCMO, an effective fact n* was introduced to replace n (the number of layer). All the calculated values of ρ (the resistivity of multilayer films) accorded with the experimental values.     

复杂企业网服务器端Analogy Factory设计模式

利用servlet良好的可扩展性，提出一种全新的Web服务器端设计模式－Analogy Factory模式，将企业的业务逻辑从servlet中剥离，以独立的接口继承体系实现，并用动态加载方式获得其实例，可以在不重新编译服务器端控制逻辑的前提下更新功能，甚至加入新模块，从而适应企业复杂多变的网络环境和应用需求。本设计模式运用于实际系统的开发，较好地解决了复杂网络的网络拥塞、驱动冲突和软件混乱等问题。