Crystallization and phase transformation kinetics of poly(1-butene)/MWCNT nanocomposites

Poly(1-butene)/MWCNT nanocomposites were prepared by simple melt processing technique. Crystallization, crystal-to-crystal phase transformation and spherulitic morphology were studied using differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and optical microscopy (OM). The non-isothermal crystallization exhibited higher values of Z_t derived from Avrami theory and lower values of F(T) obtained from Avrami-Ozawa analysis, while the isothermal crystallization revealed a significant increase in crystallization temperatures and lower crystallization half times compared to pristine PB. The observed changes in the crystallization kinetics were ascribed to the enhanced nucleation of PB in the presence of MWCNT. The nucleating activity calculated from the non-isothermal crystallization data revealed that the MWCNTs provide an active surface for the nucleation of PB. The optical micrographs exhibited significantly smaller crystallites with disordered morphology for the nanocomposites compared to the well defined spherulitic morphology for pristine PB. The rate of phase transformation from kinetically favored tetragonal to thermodynamically stable hexagonal form was noticeably enhanced as evidenced by the reduction in the half time for phase transformation from 58 h to 25 h for PB reinforced with 7% MWCNT.     

Analysis of polymer blend morphology by transmission and reflection light scattering techniques

Optical inspection is a potentially powerful and practical tool to collect information on polymer blend morphology for on-line quality and process control. This paper describes two approaches for the characterization of polymer blend materials by multiple light scattering. A quantitative evaluation of spectral turbidimetry (scattering of transmitted light) is presented and an adaptation of this technique for monitoring particle size, independent of the volume fraction is demonstrated. Such a procedure is applicable to materials in film form. A different approach is presented for the analysis of nearly spherical particles in optically thick samples: the diffuse reflection pattern surrounding the position of incidence of a focused light beam on the surface of the turbid medium is scanned by a single side imaging system. A spectral pseudo-transmittance signal processing technique provides particle size information again independent of the volume fraction: Both techniques have been tested using well characterized polystyrene microspheres suspended in water as well as poly(methyl) (methacrylate)/polystyrene polymer blends.     

《抱朴子》反义词的判定与类型

参酌各家之说确定了判定反义词的原则和对反义词的统计方法,并从词性和反义词概念间的关系两个不同的角度对《抱朴子》中的反义词进行了分类,从而加深了对反义词性质和作用的了解。     

基于NIOSⅡ的数字电子钟设计与实现

以NioslCycloneEPIC20F400C7开发板为硬件平台,利用OuartusⅡ、SOPCBuilder和NiosⅡIDE软件设计来实现一个基于SOPC的多功能数字电子钟,该电子钟系统由FPGA部分（包括Nios11CPU核、内部定时器、Avalon总线等）、存储器部分（包括SRAM、FLASH）和外围元件部分（按键、LCD显示器）三大部分构成,经过C语言编程使该电子钟具有能够在液晶屏上显示帮助信息,具有时问、日期、状态提示的功能,并可利用4个按键对时间（小时和分钟）、日期（年月日）进行设置（包括退出设置）。经测试该电子钟具有较好的时间精度。     

图书馆的建筑设计格局与图书馆的管理思考

图书馆的建筑设计首要考虑的就是图书馆的管理。数字化图书馆的建设已经来临,我们从唐宋以前的宫廷藏书建筑、明代皇家藏书建筑、清代皇家藏书建筑、私人藏书楼及现代图书馆的藏书建筑格局来比较现在的高校图书馆的建筑设计格局。因而深入、系统地研究图书馆建筑功能、空间的组成及空间布局结构的变化和发展;归纳、总结高校图书馆建筑的设计理念和方法。通过这些研究,把从中得到的启发、经验运用于实践,图书馆建筑设计格局真正地服务于教学、科研,为中国高等教育事业的发展做出应有的贡献。     

浅析图书馆有色金属公共信息服务平台的建设

为了充分发挥图书馆的技术资源优势,缓解企事业单位文献信息资源不足的矛盾,我馆提出建设一个有色金属公共信息服务平台,使图书馆更好地为我市地方经济建设服务,提升图书馆的服务能力和服务水平;更好地发挥图书馆的窗口作用和纽带作用,与地方搭起一个连接的桥梁,更好地为市政府和我市各企事业单位服务。     

Molten salts/ceramic-foam matrix composites by melt infiltration method as energy storage material

A new type of high temperature energy storage material was obtained through the melt infiltration method, using compounding SiC ceramic foam as matrix and Na₂SO₄ as phase change material. The resulting composite material was measured by XRD, SEM, TG-DSC methods. The experimental results indicate that the composite is composed of silicon carbide, sodium sulfate and square quartz, and no chemical reactions occurs between Na₂SO₄ and SiC matrix. Na₂SO₄ has a good bonding with the SiC ceramic foam matrix. As the composite material is characterized by high thermal energy storage density and high thermal conductivity, it is suit for energy storage under high temperature. Funded by the “863” Hi-Tech Research and Development Program of China (2008AA05Z418)     

Monitoring the cure of a composite matrix resin with microdielectrometry

This paper presents a study of the cure of glass and graphite fiber epoxy composites using dielectric monitoring techniques. Initial results reported here deal with the neat resin and the relationship between its conductivity and corresponding changes in glass transition temperature during cure.     

Inhomogeneous Density in Die Compaction: Experiments and Finite-Element Calculations

X-ray density measurements and two-color powder displacement observations were used to determine the reliability of the cylindrical test cell as a source of data for a plasticity model of granular materials. Calculations with such a model agree well with the experimental density distribution, for the cylindrical test cell itself and for a cylindrical die, compacted from one side by means of a profiled plunger .