Dynamic computing rough approximations approach to time-evolving information granule interval-valued ordered information system

With the advent of Big Data era has seen both the volumes and update rates of data increase rapidly. The granular structure of an information system is evolving with time when redundancy data leaves and new data arrives. In order to quickly achieve the rough approximations of dynamic attribute set interval-valued ordered information system that the attribute set varies over time. In this study, we proposed two dynamic computing rough approximations approaches for time-evolving information granule interval-valued ordered information system which induced by the deletion or addition some attributes, respectively. The updating mechanisms enable obtaining additional knowledge from the varied data without forgetting the prior knowledge. According to these established computing rules, two corresponding dynamic computing algorithms are designed and some examples are illustrated to explain updating principles and show computing process. Furthermore, a series of experiments were conducted to evaluate the computational efficiency of the studied updating mechanisms based on several UCI datasets. The experimental results clearly indicate that these methods significantly outperform the traditional approaches with a dramatic reduction in the computational efficiency to update the rough approximations.     

一种基于证据推理的视频运动目标融合检测算法

为了解决复杂场景下传统的运动目标检测问题, 利用证据推理—–谨慎有序加权平均方法(COWA-ER), 提出一种综合使用混合高斯、均值滤波和码本的多方法融合的检测方法. 该融合检测算法以上述3 种检测方法为准则建立一个多准则决策框架, 通过双阈值检测法来表征检测过程中的不确定性, 最终利用COWA-ER 方法进行决策级融合, 实现多种方法的优势互补. 实验表明, 所提出的融合检测算法具有更理想的目标检测效果, 能有效应对诸如阴影及光照突变等问题对检测性能的影响.

     

堆垛机组导向装置的优化设计

堆垛机组导向装置的优化设计经导柱式导向装置、早期连杆式导向装置、新型连杆式导向装置三个过程，通过不断的技术改进，产品得到逐步完善。本文从优化设计角度，分析原有结构的不足，推出导向装置的新型结构形式并提高了堆垛机组导向装置的动力臂幅度，使机组动作更加灵活、可靠。     

Microstructures and mechanical properties of Mg–13Gd–5Er–1Zn–0.3Zr alloy

Microstructure and mechanical properties of the Mg–13Gd–5Er–1Zn–0.3Zr alloy were investigated by optimal microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS) and transmission electron microscopy (TEM) in the present investigation. The results suggested that the basal plane stacking faults (SF) of Mg crystal was present together with the precipitation of the (Mg,Zn)₅(Gd,Er) phase. The parts of the (Mg,Zn)₅(Gd,Er) precipitate were dissolved into the matrix during homogenization treatment at 733 K. In addition, a new kind of lamellar-shaped 14H long-period stacking-ordered (LPSO) structure was precipitated from the stacking faults of basal plane during homogenization treatment at 733 K. However, the unstable β′ phase was precipitated in the extruded grains after ageing treatment. The presence of both the 14H-LPSO structure and the β′ precipitate resulted in a great enhancement in mechanical properties. The values of the tensile yield strength and ultimate tensile strength were 338.8 MPa and 410.9 MPa, respectively.     

Electrostatic Control of Structure in Self‐Assembled Membranes

Self‐assembling peptide amphiphiles (PAs) can form hierarchically ordered membranes when brought in contact with aqueous polyelectrolytes of the opposite charge by rapidly creating a diffusion barrier composed of filamentous nanostructures parallel to the plane of the incipient membrane. Following this event, osmotic forces and charge complexation template nanofiber growth perpendicular to the plane of the membrane in a dynamic self‐assembly process. In this work, we show that this hierarchical structure requires massive interfacial aggregation of PA molecules, suggesting the importance of rapid diffusion barrier formation. Strong PA aggregation is induced here through the use of heparin‐binding PAs with heparin and also with polyelectrolytes of varying charge density. Small angle X‐ray scattering shows that in the case of weak PA‐polyelectrolyte interaction, membranes formed display a cubic phase ordering on the nanoscale that likely results from clusters of PA nanostructures surrounded by polyelectrolyte chains.     

Structural change in mercerized cotton fibers on cellulase treatment

Cotton fibers treated with liquid ammonia and sodium hydroxide were hydrolyzed with crude cellulase. The structural change in the fibers due to the cellulase treatment was examined in relation to the apparent affinity of Congo Red. The cellulose III crystalline structure collapsed and generated intermediate‐molecular‐ordered regions on cellulase treatment. Adsorption of Congo Red occurred on the crystallite surfaces of cellulose II and cellulose III that was transformed from cellulose II. The fiber, the dominant crystallite phase of which was cellulose III that was transformed from cellulose II, had a considerably increased apparent affinity after cellulase treatment. The intermediate structure on the crystallite surface was associated with the adsorption of Congo Red in the cases of cellulose II and cellulose III. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1675–1680, 2001     

B2结构的铝-镝金属间化合物位错性质的研究

采用截断近似法,研究了B2结构的铝-镝(B2-Al Dy)金属间化合物{110}面的位错性质。结果表明,伯格斯矢量为<110>方向的螺位错、刃位错和混合位错的芯宽度都要比<100>方向窄。它们相应的不稳定层错能存在γus<110>大于γus<001>的关系,可见,不稳定层错能是影响具有B2结构的金属间化合物位错性质的重要因素之一。B2-Al Dy滑移系为<111>{110}的位错,除了位错角为54.7°的位错以外,其他位错角的弹性应变能都要大于失配能,而且在相同周期内看,它们的相位总是相反;位错角为54.7°的位错,失配能比弹性应变能大,而且两者在相同周期内同相位。总体来说,B2-Al Dy的{110}面上<100>、<110>和<111>方向的位错,随着位错角的减小(<111>方向的54.7°的位错角除外),总能量以及相应的应力都依次增大。     

强磁场辅助合成FePtCu纳米粒子及其有序结构调控

强磁场能够将高的磁化能量无接触地传递到材料的原子尺度,改变材料的热力学状态,影响原子和分子的排列、匹配、迁移等行为,因此本研究将强磁场引入到湿化学法中,合成高有序度的FePtCu纳米粒子。研究表明：磁场下制备的FePtCu纳米粒子呈球形,形貌、尺寸均一,分散度较好。随着磁场强度增加,FePtCu纳米粒子的尺寸增加,有序度(s)和矫顽力逐渐提高。在6 T强磁场下,获得了尺寸约为11 nm,s为0.8985的L10-FePtCu纳米粒子。强磁场对粒子的磁化作用造成晶格应变,导致空位或缺陷形成,从而有效加速Fe和Pt原子的有序扩散,促进了FePt纳米粒子的无序-有序转化。强磁场辅助可实现对有序结构的调控,该方法为直接制备L10结构纳米材料提供了一种新思路。关键词：强磁场;湿化学法;FePtCu;纳米粒子;有序结构