Polytriphenylamine: A high power and high capacity cathode material for rechargeable lithium batteries

Polytriphenylamine (PTPAn) was chemically synthesized and tested as a cathode material for high-rate storage and delivery of electrochemical energy. It is found that the polymer has not only superior high power capability but also high energy density at prolonged cycling. At a moderate rate of 0.5C, PTPAn gives a high average discharge voltage of 3.8 V and quite a high capacity of 103 mAh g⁻¹, which is very close to the theoretical capacity (109 mAh g⁻¹) as expected from one electron transfer per triphenylamine monomer. Even cycled at a very high rate of 20C, the polymer can still deliver a capacity of 90 mAh g⁻¹ at 1000th cycle with a nearly 100% coulombic efficiency. The excellent electrochemical performances of PTPAn are explained from the structural specificity of the polymer where the radical redox centers are stabilized and protected by conductive polymeric backbone, making the radical redox and charge-transporting processes kinetically facile for high-rate charge and discharge.     

火炬树树叶清除自由基作用的研究

分别用DPPH法、TBA法和化学发光法测定了火炬树树叶提取物对自由基的清除作用。结果表明:火炬树树叶各提取物对DPPH自由基均有清除作用,其中以乙酸乙酯提取物的清除能力最强;各提取物对亚油酸脂质过氧化体系亦有良好的抑制作用,乙酸乙酯提取物的抑制作用强于水提取物。火炬树树叶水提物对碱性连苯三酚体系产生的超氧阴离子自由基(O2•)也有较强的清除作用。     

Ozone/electron beam process for water treatment: Design,limitations and economic considerations

Electron beam irradiation of water is technically the easiest way to generate OH free radicals but the efficiency of the irradiation process as an advanced oxidation process (AOP) is deteriorated by reducing species formed simultaneously with the OH free radicals. Addition of ozone to the water before or during irradiation improves the efficiency by converting the reducing species into OH free radicals and turning the irradiation process into a full AOP. The main reaction pathways of the primary species formed by the action of ionizing radiation on water in a natural groundwater with and without the presence of ozone are reviewed. Based on these data an explanation of both the dose rate effect and the ozone effect is attempted. New data are presented which illustrate the effect of alkalinity on the way in which ozone is introduced into the water, and the impact of both water matrix and chemical structure of the pollutants to the efficacy of the ozone/electron beam process.     

Radical parametrizations of algebraic curves by adjoint curves

We present algorithms for parametrizing by radicals an irreducible curve, not necessarily plane, when the genus is less than or equal to 4 and the curve is defined over an algebraically closed field of characteristic zero. In addition, we also present an algorithm for parametrizing by radicals any irreducible plane curve of degree d having at least a point of multiplicity d−r, with 1≤r≤4 and, as a consequence, every irreducible plane curve of degree d≤5 and every irreducible singular plane curve of degree 6.     

彝文输入法自由编码方案的推广及应用

简述并探讨基于自由拆分模式的彝文输入法编码优化方案,从文字字形结构特点出发,运用自由拆分模式的形码编码方案,对比分析规范彝文文字和云南部分少数民族文字,探究其共性,以实现自由编码方案在云南少数民族文字中的推广和应用,从而为云南少数民族地区文字信息化处理的研究提供方法和内容上的参考。     

边界条件对正庚烷均质压燃燃烧过程的影响

应用零维详细化学反应动力学模型,对不同边界条件下正庚烷（n—heptane）均质压燃燃烧反应的化学反应动力学过程进行了数值模拟研究,得出了以初始温度和燃料当量空燃比这两类边界条件为函数,压缩比为17,转速为1400r／min的HCCI全工况解。结果表明：HCCI燃烧分为完全燃烧区域、低温反应和蓝焰反应区域、仅发生低温反应区域和失火区域;不发生热焰反应的关键是反应H＋O2=O＋OH进行程度浅,不能生成足够的OH自由基使CO氧化成CO2;蓝焰反应也不发生而仅发生低温反应的关键是H2O2分解反应的进行程度浅,H2O2只有在缸内温度达到1000K时才能快速分解,这就不能生成足够的OH自由基使甲醛转化成CO2低温反应和蓝焰反应区域是高CO排放区,仅发生低温反应的区域是高甲醛排放区。     

Synthesis of Alkyl Sulfur-Functionalized Oleic Acid-Based Polymethacrylates and Their Application as Viscosity Index Improvers in a Mineral Paraffinic Lube Oil

This work describes the synthesis of alkyl sulfur-functionalized polymethacrylate-based Viscosity Index Improvers (VII) derived from oleic acid (OLA) for mineral paraffinic lubricating oils. In this strategy, OLA was first quantitatively ramified by alkyl thiols containing long aliphatic chains through thiol-ene coupling as demonstrated by ¹H NMR spectroscopy with the complete consumption of OLA internal double bonds. The resulting alkyl sulfur-functionalized OLA-based derivatives were methacrylated through Steglich esterification in order to afford highly suitable hydrophobic OLA-based monomers which, as far as we know, have not been described yet in the current literature. High polymethacrylate molecular weights were reached through radical polymerization despite the long alkyl pendant chains contained in their backbones. Finally, the resulting alkyl sulfur-functionalized OLA-based polymethacrylates have been blended in a mineral paraffinic oil (MPO) of reference at 5 wt% and evaluated as VII. Rheological measurements revealed that polymer thickening powers were significantly improved in oil with temperature and promoted by increasing the pendant alkyl thiol contained in polymer backbones. Moreover, the viscosity index of MPO was significantly improved with the addition of both synthesized homopolymers which confirmed their efficiency as VII. In the meantime, these results have been compared with a previously reported polymer, the poly(2-[methacryloyloxy]ethyl oleate) (PMAEO), which demonstrated a lower VII efficiency compared with its analogous polymethacrylates containing an additional alkyl chain in their pendant chains.     

Adhesion of electron beam curable coatings on metal substrates

Electron beam (EB) curing is growing more and more important as a curing technique in industrial coatings, for example on substrates like wood, paper and plastics. However, commercial applications of EB curing on metal substrates are rather limited. The main technical cause for this originates from the insufficient adhesion and flexibility shown by EB cured coatings when applied on metal parts. However, adhesion and flexibility can be improved by various ways, in particular via a proper choice of the chemical pretreatment of the substrate. Adhesion of coatings, based on acrylated resins, on hot dipped galvanized steel can be improved dramatically by using a pretreatment, which is not usual in the current field of commercial coil coating. Pretreatments investigated show no relationship to surface tension, so it is highly probable that a chemical graft reaction, initiated by the electron beam, occurs at the interface of the coating and pretreatment layer. Experiments also show that cationic curing binder systems show promise with respect to adhesion and flexibility. Without optimizing the coating formulation (no wetting agents or other additives are used) relatively good adhesion and flexibility can be obtained on hot dipped galvanized steel, under both wet and dry conditions. The adhesion and flexibility are shown to be dependent on the radiation dose, and can be further improved by post-heating. In this case the polymer network gets the opportunity to relax internal stresses that are built up during the cure reaction.     

MMA－ST乳液共聚合乳胶粒增长阶段和聚合反应完成阶段数学模型及计算机模拟

在乳液共聚合动力学研究的基础上，考虑到自由基解吸、体积效应、凝胶效应和玻璃化效应等因素，建立了甲基丙烯酸甲酯－苯乙烯乳液共聚合聚合反应完成阶段的数学模型，并进行了计算机模拟，利用该数学模型预计了聚合反应速率、自由基在乳胶粒间的分布及平均自由基数，并将模型预计结果与实验数据进行了比较和讨论     

Fate of Cr(III) during Ozonation of Secondary Municipal Wastewater Effluent

ABSTRACT

In the present study, the fate of trivalent chromium (Cr(III)) during ozonation of ultrapurified water and wastewater effluent was investigated. In experiments conducted in phosphate buffered ultrapurified water, O₃ alone in excess was inefficient to oxidize Cr(III) (only about 10–15% of total Cr(III) content), while in presence of the secondary oxidant, OH radical, almost all Cr(III) was oxidized to hexavalent chromium (Cr(VI)). In a wastewater effluent, spiked with Cr(III), only about 10–20% of Cr(III) was oxidized with specific ozone doses in the range 0.15–1.5 gO₃/gDOC, although O₃ and OH radical were both available for reaction. Cr(VI) formation was monitored in parallel with the abatement of some common micropollutants, reacting with differing apparent second-order rate constants with ozone, decreasing in the order carbamazepine>> benzotriazole> atrazine> p-chlorobenzoic acid (pCBA). Carbamazepine and benzotriazole were abated to >80% for specific O₃ doses of 0.3 gO₃/gDOC and 0.8 gO₃/gDOC, respectively. The more ozone-resistant compounds (atrazine and pCBA) required a specific ozone dose of about 1.25 gO₃/gDOC for the same relative abatement. At this specific ozone dose (i.e., 1.25 gO₃/gDOC), only about 20% of Cr(III) was oxidized to Cr(VI), whereas only 10% of Cr(III) was oxidized to Cr(VI) at a more realistic specific ozone dose for enhanced wastewater treatment for micropollutant abatement (0.5 gO₃/gDOC). Therefore, for typical Cr(III) levels in municipal wastewaters, effluent ozonation only leads to toxicologically insignificant Cr(VI) concentrations.