Synthesis and kinetic studies of UV‐curable urethane‐acrylates

The UV‐curable urethane‐acrylates based on 2‐hydroxyethyl methacrylate (HEMA)‐terminated polyurethane (PU) for lithographic and coating applications are investigated in this study. Series of PU prepolymers were made from 4,4‐diphenyl methane diisocyanate (MDI), poly(propylene oxide) glycol (PPG 400), poly(butylene adipate)glycol (PBA 500), or poly(tetramethylene oxide) glycol (PTMO 1000) and are terminated with HEMA. The 2,2‐azobisisobutyronitrile (AIBN) was used as a UV‐initiator under air atmosphere. The curing kinetics of HEMA‐terminated PU film were studied. The curing analysis, using FTIR and reaction kinetics, indicate the reaction rate equation correlates well with the film thickness [T], initiator concentration [I], unreacted double bond concentration [C?C], and exposed energy [E] of the reaction system. The kinetic rate equation for the UV‐curable reaction can be written as © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3162–3166, 2004     

基于S3C2440嵌入式视频传输系统的研究与设计

如今嵌入式和视频行业发展的如火如荼,视频传输也得到了很好的发展,而很多视频传输设备都比较昂贵且移动不灵活.鉴于此,设计出了以S3C2440为核心芯片,并在此基础上结合linux环境下的GStreamer流媒体框架的视频传输系统,系统采用无线的传输方式.经过对系统测试,此系统能流畅的播放传输的视频并且移动灵活,达到预期目标,并且该系统简洁、成本低具备实际的应用前景.     

中国铝用炭素50年的技术创新模式分析

简要叙述了技术创新的概念和技术创新的主要模式,对我国铝用炭素50年来的若干主要技术创新点的技术创新模式进行分析,并分析了我国铝用炭素技术创新的诱导因素和技术创新体系,提出一些不足和努力方向。     

Morphology and thermal stability of BR/clay composites prepared by a new method

A new potential preparation method named in situ organic modification was used to prepare intercalated polybutadiene rubber (BR)/clay/dimethyl dihydrogenated tallow ammonium chloride (DDAC) composites. That is, BR, pristine clay, and intercalatant DDAC were directly mixed in a Haake rheometer without pretreating the pristine clay with the intercalatant. The morphology of the BR/clay composites was investigated by means of X‐ray diffraction and scanning electron microscopy. The thermal stability of the BR/clay composites was analyzed by thermogravimetric analysis (TGA). The dispersion of clay particles in the BR/clay/DDAC composites is much better than that in the BR/pristine clay and similar to that in the BR/organoclay DK4 (modified with DDAC) composites. BR/clay/DDAC composites have much higher thermal stability than the gum BR, BR/pristine clay, and BR/DK4 composites. The clay/intercalatant ratio has little influence on the thermal stability of the BR/clay/DDAC composites, while clay content has a significant effect on their thermal stability. The enhanced thermal stability of the BR/clay/DDAC composites is related to the dispersion state of clay particles in BR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 905–913, 2006     

一种基于差分进化和免疫克隆选择算法的混合优化方法

为了提高免疫克隆选择算法的搜索能力,提出了一种基于差分进化和免疫克隆选择算法的混合优化方法。该方法采用差分进化提高免疫克隆选择算法的抗体亲和度,并对该算法的收敛性进行了分析。为了测试该算法的有效性,将该算法应用于函数优化问题中。仿真结果表明,该方法具有更高的收敛速度和收敛精度。     

运动发酵单胞原生质球的形成和再生

运动发酵单胞(Zymomonas mobilis)ATCC29191菌株在含1～3g/L甘氨酸的液体培育12小时的菌体,用含20g/L的溶菌酶溶液处理12小时,可以稳定得到80％～90％的原生质球。原生质球稀释后在底层再生培养基上涂布,上面复盖一层半固体培养基,30℃培养5～7小时,再生率可达10~(-2)水平。     

聚硅氧硅氮烷改性烯丙基酚醛杂化树脂的研究

采用二苯基硅二醇与含乙烯基的聚硅氮烷（SiN08）反应，合成了三种含二苯基硅氧链节的聚硅氧硅氮炕MPSZ-1、MPSZ-2、MPSZ-3；并用于烯丙基酚醛（AP）树脂的改性。与纯AP树脂相比，聚硅氧硅氮烷改性烯丙基酚醛树脂（MPSZ／AP）的热分解温度和高温残余质量分数都有较大提高。在N2气氛中，AP的质量损失率为5％时的温度为383℃，900℃残余质量分数为33．0％；MPSZ-1／AP的质量损失率为5％时的温度为465℃，900℃残余质量分数为74．4％。在空气气氛中，AP的900℃残余质量分数仅1．5％，MPSZ-1／AP的900℃残余质量分数为33．8％。MPSZ-1／AP体系的热分解温度和高温残余质量分数与SiN08／AP体系相当，而其固化质量损失率较低，仅为4．4％，适合采用树脂传递模塑（RTM）成形工艺制成复合材料。对聚硅氮烷／AP树脂固化过程的初步研究表明，Si—N键在固化过程中起主要作用。     

Comparatively electrochemical studies at different operational temperatures for the effect of nanoclay platelets on the anticorrosion efficiency of DBSA-doped polyaniline/Na-MMT clay nanocomposite coatings

In this paper, DBSA-doped polyaniline (PANI)/Na⁺-montmorillonite (MMT) clay nanocomposite (PCN) materials have been successfully prepared with dodecylbenzenesulfonic acid (DBSA) as emulsifier and dopant for the emulsion polymerization of aniline. The as-prepared DBSA-doped samples were subsequently characterized by FTIR spectroscopy, WAXRD patterns and TEM. It should be noted that the nanocomposite coating containing 1 wt.% of clay loading was found to exhibit an observable enhanced corrosion protection on cold-rolled steel (CRS) electrode at higher operational temperature of 50 °C, which was even better than that of uncoated and electrode-coated with PANI alone at room temperature of 30 °C based on the electrochemical parameter evaluations (e.g., E_corr, R_p, I_corr, R_corr and impedance). In this work, all electrochemical measurements were performed at a double-wall jacketed cell, covered with a glass plate, through which water was circulated from a thermostat to maintain a constant operational temperature of 30, 40 and 50 ± 0.5 °C. Moreover, a series of electrochemical parameters shown in Tafel, Nyquist and Bode plots were all used to evaluate PCN coatings at three different operational temperatures in 5 wt.% aqueous NaCl electrolyte. Effect of material composition on the molecular weight and optical properties of neat PANI and PCN materials, in the form of solution, were studied by gel permeation chromatography (GPC) and UV-vis spectra, respectively. Finally, electrical conductivity at three different operational temperatures of PANI and PCN powder-pressed pellets doped with different inorganic acids such as HCl, HNO₃ and H₂SO₄ was also investigated through the measurements of standard four-point-probe technique.     

Gd_3Al_5O_(12)∶Eu~(3 )柠檬酸盐硝酸盐燃烧法合成及其发光性能研究

采用柠檬酸盐硝酸盐燃烧法,在较低的温度(900℃)下成功地合成单一晶相Gd3Al5O12∶Eu3 发光粉体,紫外激发荧光光谱分析表明,粉体615 nm和593 nm荧光发射源于Eu3 的5D0-7F2和5D0-7F1跃迁.该方法中各工艺条件(如pH值、柠檬酸/金属离子比、煅烧温度)对Gd3Al5O12∶Eu3 发光性能均有影响,通过试验得出了获得最佳发光性能荧光粉体的工艺参数.     

硫酸脲分解磷矿反应机理探讨

以硫酸脲分解磷矿是一种新的N、P复肥生产方法,硫酸脲分解磷矿有其特殊的反应机理。利用在线显微摄像与物化分析相结合,可以很好地表征硫酸脲分解磷矿的反应机理。实验表明:硫酸脲与磷矿在液固接触的界面微区进行反应,反应微区内有离解、反应、结晶、复合等过程,并伴随有晶型转变。反应生成的硫酸钙晶体复盖反应粒子表面,形成包裹层增大传质阻力。反应物质通过CaSO40.5H2O晶膜的传递阻力是影响整个反应过程的重要因素。