Manufacturing a TiAl alloy by high-energy ball milling and subsequent reactive sintering

A TiAl alloy was fabricated by high-energy ball milling and subsequent reactive sintering from the mixed powders of Ti and Al. High-energy ball milling produced a kind of particular composite powders with an extremely fine altemative Ti and Al lamella structure. The composite powders not only possessed good consolidation and densification characteristics, but also resulted in the augment of nucleation rate of α and γ titanium aluminides during solid-phase reactive sintering After a series of processing, pressing, degassing, extrusion, and sintering, the resultant TiAl alloy presented high relative density and refined grain sizes of （α2 ＋ γ） lamella and γ phases. The compressive yield strength of the sintered TiAl reached 600 MPa at 800℃.     

纳米硫化铋-锌复合镀膜的制备及其抗菌性能研究

目的将锌镀层与具有光催化抗菌性能的纳米粒子复合,实现对锌镀层的改性,成功制备一种具有光催化抗菌性能的功能性复合镀层。方法通过向弱酸性硫酸盐锌镀液中加入梯度浓度具有可见光催化杀菌性能的硫化铋纳米粒子,在20#碳钢表面利用恒电流法一步成功制备了系列硫化铋-锌复合镀膜。利用电化学工作站监测了沉积过程中的沉积电位,分别记录沉积前和沉积后的样品质量并测量沉积面积,通过计算,确定了沉积过程的电流效率。通过扫描电子显微镜(SEM)、X-射线晶体衍射仪(XRD)及电子能谱仪(EDS)对镀层进行了形貌及成分分析,采用大肠杆菌作为代表性的细菌,检测了复合镀膜的抗菌性能。结果与纯锌镀膜相比,硫化铋的加入显著促进了(100)晶相的晶体生长,而抑制了(102)晶相的晶体生长,使镀膜形貌由标准六方晶系变为块状晶体;硫化铋的加入使沉积电位变得更正,且随硫化铋添加量的增加,变正增幅变大;硫化铋的加入使电沉积过程的电流效率与纯锌镀膜的电流效率相比增大了5%左右,但硫化铋的添加量对电流效率的影响不大;硫化铋-锌复合镀膜在可见光下对大肠杆菌具有良好的抗杀性能,且硫化铋的复合量越高,抗菌效果越好。结论通过笔者提出的电沉积方法,硫化铋可成功复合到了锌镀膜中,从而使硫化铋-锌复合镀膜获得了良好的抗菌性能,最终发现当镀液中硫化铋质量浓度为2 g/L时,硫化铋在锌镀层中的复合量最高,抗菌性能最好。     

润湿剂种类对热烧结锌铝涂层性能的影响

用6种不同类型的润湿剂制备涂层。采用SEM方法分析了涂层的表面微观形貌,通过胶带试验、盐雾试验、自腐蚀电位-时间曲线、阳极极化曲线等方法研究所制备涂层的结合力、耐蚀性和电化学性能,筛选出的3种聚合多元醇类润湿剂涂层性能良好。润湿剂是影响涂层结合力的重要因素,对涂层的耐盐雾腐蚀性能和电化学性能均有影响。     

A hybrid fuzzy model for selecting and evaluating the e-book business model: A case study on Taiwan e-book firms

This study evaluates an appropriate business model for e-book firms in Taiwan. We apply expert questionnaires to calculate the weights, which contain five criteria, namely, business strategy (BS), finance characteristics (FC), market characteristics (MC), quality measurements of product and service (QS) and implementation (IM) (BCCSM) for the capability of developing the firms’ business. Then, a fuzzy analytic hierarchy process (FAHP) is adopted to explore the weights of indices, and the VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR), grey relation analysis (GRA), and the technique for order preference by similarity to ideal solution (TOPSIS) are utilized to rank the three alternatives. The results show that a single brand is the best e-book firms’ business strategy that is simultaneously integrated by content, platforms, and devices, while the top two weights of the evaluation criteria are the business strategy and market characteristics to enable firms to develop an appropriate e-book business model.     

2D转3D处理中深度图超平滑处理算法的研究与硬件设计

该文研究了一种2D转3D处理中深度图超平滑处理算法,本算法在加权平均滤波器的基础上引入像素相关度,对平滑窗内的像素点进行选择,减少了区域外的点对中心像素的影响,有效解决了均值滤波器能引起区域边缘模糊的问题。同时,使用verilog语言实现了此算法,并且通过modelsim仿真软件进行了仿真。     

一种基于改进型边沿线平均算法的去隔行设计

该文在原有边沿线平均去隔行算法的基础上设计和实现了改进型的边沿线平均算法。本系统包括rgb2yuv,edge_detection,Sif,yuv2rgb 4个模块,可调参数通过AMBA总线配置。其中Sif模块为本文设计的重点.本设计用VerilogHDL语言实现,同时并为此设计搭建了功能完备的Modelsim仿真环境,进行了仿真验证,最后用FPGA实现其功能。     

SIM300和nRF24LE1的多通道无线数据采集系统设计

设计了由GSM/GPRS模块SIM300和射频收发芯片nRF24LE1组成的无线数据采集系统,实现了对数据的采集与无线传输。系统由嵌入高速单片机的nRF24LE1芯片完成对多路数据的采集、处理和收发,并由SIM300将数据通过网络传递给TCP服务器和手机终端。在完成系统的硬件设计和软件开发的过程中,重点探究了nRF24LE1芯片的多通道收发过程和TCP服务器的建立。该系统具有功耗低、扩展方便等优点,适合多种无线数据采集和传输的场合。     

Robust video hashing based on representative-dispersive frames

This study proposes a robust video hashing for video copy detection.The proposed method,which is based on representative-dispersive frames(R-D frames),can reveal the global and local information of a video.In this method,a video is represented as a graph with frames as vertices.A similarity measure is proposed to calculate the weights between edges.To select R-D frames,the adjacency matrix of the generated graph is constructed,and the adjacency number of each vertex is calculated,and then some vertices that represent the R-D frames of the video are selected.To reveal the temporal and spatial information of the video,all R-D frames are scanned to constitute an image called video tomography image,the fourth-order cumulant of which is calculated to generate a hash sequence that can inherently describe the corresponding video.Experimental results show that the proposed video hashing is resistant to geometric attacks on frames and channel impairments on transmission.     

Data filtering based least squares algorithms for multivariable CARAR-like systems

This paper focuses on the identification problem of multivariable controlled autoregressive autoregressive (CARAR-like) systems. The corresponding identification model contains a parameter vector and a parameter matrix, and thus the conventional least squares methods cannot be applied to directly estimate the parameters of the systems. By using the hierarchical identification principle, this paper presents a hierarchical generalized least squares algorithm and a filtering based hierarchical least squares algorithm for the multivariable CARAR-like systems. The simulation results show that the two hierarchical least squares algorithms are effective.