Catalytic activity of cobalt deposited on nanostructured poly(p-xylylene) films

Nanostructured and planar films of poly(p-xylylene) (PPX) are fabricated by an oblique angle polymerization method and coated with cobalt using electroless deposition. The catalytic activity of cobalt coated on the nanostructured and planar PPX films is studied by measuring the rate of hydrogen evolution by the hydrolysis of alkaline-stabilized sodium borohydride (NaBH₄) solution. The hydrogen release rate data show an asymptotic increase for the structured PPX film as a function of the electroless bath time, but the planar PPX films show a lower catalytic activity due to the inefficiency of cobalt deposition. The hydrogen release rate of the cobalt-coated nanostructured PPX film shows a rate between 2000 and 4250 mL(g min)⁻¹ (i.e., rate of hydrogen gas per cobalt mass at room temperature and pressure), which is comparable to the values obtained on platinum, and ruthenium systems.     

卡铂在氯化钠或葡萄糖水溶液中的取代动力学研究

用薄层色谱法确定在25℃时卡铂在氯化钠或葡萄糖水溶液中热反应的取代产物。用分光光度法测定在氯化钠水溶液中的热反应速率常数和低pH下的速率常数,探讨其反应和酸催化机理。用电导法测定卡铂在葡萄糖水溶液中的取代速率常数。通过比较,认为卡铂用葡萄糖作溶剂较好。     

过碳酸钠生产中稳定剂的选择

根据稳定剂的作用机理，介绍了过碳酸钠生产中常用的内稳定剂、外稳定剂、复合稳定剂及其加入方式和适宜用量。     

含防冻剂混凝土钢筋阻锈机理的研究

通过掺氯化钠和亚硝酸钠的模拟混凝土孔溶液中钢筋阳极极化曲线的测定 ,发现未掺氯化钠混凝土中钢筋 ,钝化膜比较稳定 ,钢筋不易腐蚀。而掺氯化钠混凝土中钢筋由于起坑电位降低 ,容易因电化学极化作用产生腐蚀。掺亚硝酸钠可以防止氯化钠引起的起坑电位的降低 ,抑制钢筋腐蚀。     

聚合硫酸铁的新型合成

以钛白粉生产废料作为原料制得了聚合硫酸铁,在常温下采用氯酸钠溶液滴加于硫酸亚铁的硫酸溶液中可使氧化还原反应完全,F e2+含量得到控制。控制[SO42-]/[F e]<1.5,1%PFS溶液pH值在2~3不产生F e(OH)3沉淀。     

Rotenone coprecipitation with biodegradable polymers by supercritical assisted atomization

The aim of this study was to coprecipitate rotenone, a biopesticide, with biodegradable polymers using supercritical assisted atomization (SAA) process. Rotenone encapsulation can protect the pesticide from degradation thus reducing the quantity to be used. Different water soluble polymers were tested, such as polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and sodium alginate. Solutions with one or two solvents and rotenone suspensions were tested to perform the experiments. Different biodegradable polymer/pesticide ratios were tested: 2 and 8 in the case of PEG⿿rotenone coprecipitates, 25, 50 and 100 in the cases of PVP⿿rotenone and alginate⿿rotenone coprecipitates. The particles obtained were spherical with the mean diameter ranging between 0.6 and 1.5 μm. The effective loading of the particles was evaluated by HPLC and the best results were obtained in the case of alginate⿿rotenone coprecipitates that show a coprecipitation efficiency close to 100% and for PEG⿿rotenone particles the efficiency was about 98%. PVP⿿rotenone composite microparticles showed the lowest coprecipitation efficiency that ranged between 30% and 50%.     

甘氨双唑钠对离体V79细胞的放射增敏作用

以离体细胞克隆形法进一步研究了甘氨双唑钠对乏氧Ｖ７９细胞的放射增敏作用。结果表明：ＳＧＤＤ的毒性较低，且对乏氧细胞的毒性比有氧时强。它对有氧细胞无增敏作用，但在乏氧情况下，对Ｖ７９细胞有明显的放射增敏效果，当ＳＧＤＤ在１．３８ｍｍｏｌ／Ｌ以下时，其ＳＥＲ值浓度的增加而增高，Ｃ１．６＝０．４８ｍｍｏｌ／Ｌ，ＳＥＦ最大值２．３时的浓度为１．３８ｍｍｏｌ／Ｌ，不到ＩＤ５０的１／７０。     

Influence of nitric acid pre-treatment on Al-Cu alloys

The enrichment of copper alloying additions near the surface of sputtering-deposited Al-1.3 at.%Cu, Al-2.7 at.%Cu and Al-30 at.%Cu alloys is investigated following immersion in nitric acid, which is used commercially as a de-smutting pre-treatment. Corrosion of the alloys is revealed at rates in the range 4-13 nm min⁻¹, leading to enrichment of copper in the alloy surface regions. Enrichments are also generated by nitric acid treatment of AA2024-T3 and AA7075-T6 alloys, with levels similar to those achieved by etching in sodium hydroxide solution. Conventional durations of de-smutting treatments in nitric acid have minor influences on the magnitude of enrichment.     

Simulation studies of the membrane exchange assembly of an all-liquid,proton exchange membrane fuel cell

A model has been designed and constructed for the all-liquid, sodium borohydride/hydrogen peroxide fuel cell under development at the University of Illinois at Urbana-Champaign. The electrochemical behavior, momentum balance, and mass balance effects within the fuel cell are modeled using the Butler–Volmer equations, Darcy's law, and Fick's law, respectively, within a finite element modeling platform. The simulations performed with the model indicate that an optimal physical design of the fuel cell's flow channel land area or current collector exists when considering the pressure differential between channels, and the diffusion layer permeability and conductivity. If properties of the diffusion layer are known, the model is an effective method of improving the fuel cell design in order to achieve higher power density.     

硬脂酰乳酸钠合成新方法及乳化性能研究

以浓硫酸为催化剂,L-乳酸与硬脂酸进行酯化反应合成了硬脂酰乳酸钠,考察了反应物配比、反应温度、浓硫酸用量、反应时间对酯合成反应的影响,最佳合成条件为：L-乳酸与硬脂酸的摩尔比是2.0,温度105℃、催化剂加入量为1.5%、反应时间为4 h.对产品的乳化性能进行了测定,结果表明硬脂酰L-乳酸钠是一种优良的乳化剂.