大塑性变形技术制备块状超细晶TiNi基形状记忆合金研究进展

详细介绍了块状超细晶TiNi基形状记忆合金的研究进展,包括其制备工艺与显微组织、马氏体相变行为、力学性能和形状记忆特性以及超弹性性能,并介绍了其在医学和工程领域的实际应用,最后探讨了块状超细晶TiNi基形状记忆合金今后的研究发展方向。     

Mechanism of formation of polyaniline flakes with high degree of crystallization using a soft template in the presence of cetyltrimethy‐lammonium bromide

Flake‐like polyaniline with various thicknesses was prepared by cationic emulsion polymerization of aniline monomer in the presence of cetyltrimethylammonium bromide (CTAB). The morphology of polyaniline with uniform and smooth flake‐like structure was observed using field‐emission scanning electron microscopy and transmission electron microscopy. The lamellar complex of (CTA)₂S₂O₈, acting as a reactive soft template for the formation of polyaniline, was investigated using low‐angle X‐ray diffraction. The soft template provides an expanding space for the growth of polyaniline, in which the oxidization of aniline monomers can construct effectively a flake‐like structure. The concentration of CTAB plays an important role in adjusting the d‐spacing of the soft template. Crystallization and composition of polyaniline were characterized using X‐ray diffraction and Fourier transform infrared spectroscopy. The X‐ray diffraction pattern has a sharp peak at 2θ = 6.4° (d‐spacing = 13.7 Å), showing that polyaniline has a solid‐state ordering structure and high degree of crystallization. Doping and dispersive experiments were also included in the study. Copyright © 2012 Society of Chemical Industry     

Effect of electron beam irradiation on polyacrylonitrile precursor fibers and stabilization process

The electron beam was imposed on the polyacrylonitrile precursor fibers before the fibers were stabilized. The effect of electron beam irradiation on the chemical structure, transverse section, and surface morphology and thermal properties of the fibers in the process of stabilization was characterized by the use of Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and differential scanning calorimeter, respectively. A parameter η = I(C?N)/[I(C?N) + I(C?N)] was defined to evaluate the extent of cyclization in the stabilization process. The kinetic parameters, viz. activation energy (E) and pre‐exponential factor (A) of the stabilization reactions, were calculated by Kissinger method. FTIR analysis indicated that the cyclization of nitrile groups was initiated at room temperature by electron beam irradiation. The transformation of C?N groups to C?N ones was accelerated in the process of stabilization. The extent of cyclization of the stabilized fibers was increased. SEM analysis indicated that irradiation could also decrease the internal and surface defects of the stabilized fibers treated at 300°C. The activation energy of cyclization reaction was reduced from 302 to 280 kJ/mol and 260 kJ/mol through 100 and 200 kGy electron beam irradiation, respectively. The reaction temperature range was expanded, and the exothermic rate was slowed down in the process of stabilization, which was the reason why the stabilized fibers have improved cyclization degree and less internal defects. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

正交试验探讨改良灭菌器提取降香挥发油的最佳条件

为确定改良灭菌器提取降香挥发油的最佳提取工艺，用正交试验法对灭菌器提取降香挥发油的提取工艺条件进行优选，以挥发油得率和乳化比值为指标，考察影响挥发油收率因素并得出最佳提取工艺。结果发现，改良灭菌器提取降香挥发油的最佳提取工艺为药材粉碎成粗粉，加入6倍量的水、浸泡2h、提取8h。此提取工艺适合实验室及工厂放大生产。     

AACF: a logic-based framework of nonmonotonic authorization and access control

针对不完全语义条件下的非单调授权和权限判决问题进行形式化研究,提出了一种新的基于逻辑的非单调授权与访问控制框架——AACF.该框架通过扩展型分层逻辑程序表达授权与访问控制策略,支持不完全语义条件下的非单调授权、权限传播及冲突检测与消解等高级特性,此外,AACF的语义查询/权限判决算法的计算复杂度证明是多项式级的.因而,AACF比现有的访问控制框架具有更好的表达能力和计算特性,且具有更好的实用性.     

Critical Scaling of the Fluctuation Conductivity for ReFeAsO (Re=Nd,Pr) Superconductors

It is studied within the scaling analysis the fluctuation conductivity under the magnetic fields in ReFeAsO (Re=Nd, Pr) superconductors reported in literatures. A crossover is firstly observed in these iron-based superconductors from the Lowest Landau level (LLL) regime above the magnetic field H _LLL∼6–7 T to the critical fluctuation region at the low field. The static exponent ν of ReFeAsO superconductors is estimated to be 1.85±0.05, which is close to that of Bi₂Sr₂CaCu₂O₈, and the dynamic exponent z of ReFeAsO superconductors deviates from the theoretical prediction but is similar to that extracted from the resistivity experiment using the crossing-point technique.     

基于APDPC的流域水污染物减排机制研究

针对我国现行的污染减排制度和减排方案与环境质量改善联系不紧密、激励约束机制不健全、减排责任落实不到位、监管与考核不力等问题,提出了基于人均累积(APDPC)的流域水污染物减排新机制,通过人均参考配额及人均累积参考配额,建立流域内不同区域间环境与经济的协调发展机制。以淮河流域为例,对安徽、河南、江苏和山东四省片区进行了实证分析,验证结果表明该方法具有公平、高效、简便、易操作等优点,具有较高的推广应用价值。     

Web浏览器动态调用Excel工作表的方法研究

基于浏览器／服务器技术和动态页面处理（ASP）技术的现代管理信息系统（MIS），需要对数据信息进行分析加工，形成各种各样的动态报表，这就要求Web浏览器能动态调用Excel工作表，针对这一问题，本文提出了几种不同的解决方案。     

高水固结充填体的抗冲击特性

在高水固结充填体单轴ＳＨＰＢ 冲击实验的基础上， 得出了充填体的的典型冲击波形； 通过对冲击过程中充填体的应变率、应变、应力及能量变化所进行的分析研究， 揭示了高水固结充填体的抗冲击特性．