铽(Ⅲ)-1,4-双(1′-苯基-3′-甲基-5′-氧代吡唑-4′-基)丁二酮-[1,4]体系荧光性质的研究及应用

本文研究了Tb(Ⅲ)-1,4-双(′-苯基-3′-甲基-5′-氧代吡唑-4′-基)丁二酮-[1,4](BPMPBD)-溴化十六烷基三甲胺(CTMAB)体系的荧光性质,探讨了响影体系荧光性质的诸因素,确定了最佳实验条件。该体系中Tb(Ⅲ)浓度以2.0×10~(-5)～1.0×10~(-10)mol/L范围内与其荧光强度呈线性关系,检测限可达到5.0×10~(-11)mol/L。应用于合成样品中微量Tb(Ⅲ)的分析,结果令人满意。     

Preparation and electrochemistry of azobenzene self-assembled monolayers on gold--long range tunneling and end-group hydrogen bonding effect

A series of thiol-functionalied azobenzene derivatives (RAzoCnSH: R=H for n=3-6, abbreviated as AzoCnSH; R=CH(3)CONH for n=4, abbreviated as aaAzoC4SH) on gold electrodes were prepared and their self-assembly and electrochemical properties were studied by cyclic voltammetry. They all formed uniform and reproducible self-assembled monolayers (SAMs) on gold and showed well-behaved voltammetric responses in aqueous solution. Both the length of the alkyl chain spacer and the H-bonding of the end acetamino group had effects on the stability and the electrochemical kinetics of the SAMs, and the effect of the H-bonding was dominant. The surface coverage of the SAMs (AzoCnSH) is gradually increased with an increase of the alkyl chain spacer length, whereas the presence of the terminal acetamino group leads to a greater increase of the surface coverage. At a low scan rate, voltammetric responses corresponding to an irreversible two-electron, two-proton reduction/oxidation of the trans-azobenzene redox center were obtained in the range of +300 mV and -800 mV, which exhibited very large peak-to-peak splitting. At a high scan rate of 500 mV/s, two steps of reversible one-electron, one-proton reduction/oxidation corresponding to the cis-isomer in azobenzene-thiol SAMs (n is odd) was clearly observed between +300 and -200 mV. The apparent electron-transfer rate is decreased with increasing distance between the azobenzene redox center and the gold electrode. The existence of the end acetamino group which restricted the conformational change during the redox process also led to a decrease of the standard rate constant, and this restriction effect is more predominant than the distance effect.     

盐生盐杆菌生长过程热动力学研究

用 LKB2 2 77生物活性检测系统测定了盐生盐杆菌 R1、J7、S9以及 R1和 J7的融合子 F9生长的产热功率曲线 .根据曲线的特征 ,建立了古生菌生长过程的热动力学方程 :ln[P· ( 1 -P/Pm) r- 1 ]=ln[P0 · ( 1 -P0 /Pm) r- 1 ]+k· t.由此求得了盐生盐杆菌的生长速率常数 ,并对此模型和融合子 F9的生长进行了讨论 .该热动力学方程描述了一系列非理想的细菌生长过程的产热功率曲线 ,并将其与经典的指数式生长模型和 lo-gistic模型进行了比较 ,它具有更广泛的适用性 .首次报道了微量热技术在古生菌中的应用     

Fe(III)与2,3-二羟基苯磺酸钠配位反应的动力学研究

[H+]在0.01～0.70mol?L-1范围内,离子强度为1.00mol?L-1,[Fe(III)]>>[配体]、[H+]>>[配体]的条件下,研究了Fe(III)与2,3-二羟基苯磺酸钠(Tiron)的配位反应.发现当[H+]≤3.00×10-2mol?L-1时,[Fe(III)]2对反应速率有明显的贡献.求得了相关反应的动力学参数,从而揭示了FeOH2+和FeOH24+与Tiron配位的解离反应途径及FeOH32+的缔合反应机制,并提出了该配位反应的可能机理.     

A systematic density functional theory study of the electronic structure of bulk and (001) surface of transition-metals carbides

A systematic study of the bulk and surface geometrical and electronic properties of a series of transition-metal carbides (TMC with TM = Ti, V, Zr, Nb, Mo, Hf, Ta, and W) by first-principles methods is presented. It is shown that in these materials the chemical bonding is strongly covalent, the cohesive energies being directly related to the bonding-antibonding gap although the shift of the center of the C(2s) band related peak in the density of states with respect to diamond indicates that some metal to carbon charge transfer does also take place. The (001) face of these metal carbides exhibits a noticeable surface rumpling which grows along the series. It is shown that neglecting surface relaxation results in very large errors on the surface energy and work function. The surface formation induces a significant shift of electronic energy levels with respect to the corresponding values in the bulk. The extent and nature of the shift can be understood from simple bonding-antibonding arguments and is enhanced by the structural rippling of this surface.     

The effect of sampling conditions on the thermal decomposition of electrolytic manganese dioxide

The effect of sampling conditions on the decomposition of electrolytic manganese dioxide using thermal methods is reported. Significant differences were observed in the mechanism of the decomposition by simply changing the reaction environment from a closed pan to an open pan configuration. The purge gas atmosphere was also observed to influence the decomposition mechanism. As a product of the decomposition is oxygen, the change in the mechanism observed between the experimental conditions may be explained in terms of the ease of removal of oxygen from the reaction site. This revised version was published online in August 2006 with corrections to the Cover Date.     

Absorption and Capture of Methane into Ionic Liquid

A reversible storage-release process switched by a temperature difference of 10℃around room temperature can be realized. This fast, recyclable, energy efficient, low cost and green system within a wide range of temperature and pressure is reported here for the first time. The system is believed to open up a new route for the storage and homogeneous utilization of methane.     

2，4，6－三苯基氧鎓盐分子内旋转受阻对其发光行为的影响

研究了４－位苯基取代基旋转受阻和旋转自由的２，４，６－三苯基氧盐的光物理性质。实验结果表明，当４－位苯基取代基旋转受阻时，氧盐化合物在激发态时引起的分子内极化程度比４－位取代基旋转自由的氧盐化合物大，即在激发态时旋转受阻氧盐化合物发生的分子内电荷转移能力较强；４－位取代基旋转自由的化合物的荧光量子产率随溶剂粘度的增大而有所增大，但旋转受阻化合物在相同的条件下则出现相反的结果。实验结果还表明，４－位取代苯基旋转受阻对化合物的荧光发射不利。     

线粒体热化学研究──Ⅳ．鱼类肝脏线粒体代谢的微量热学研究

线粒体热化学研究──Ⅳ．鱼类肝脏线粒体代谢的微量热学研究谭安民，刘义，谢昌礼，屈松生，顾贫，邓凤姣（武汉大学化学系武汉４３００７２）（武汉大学生命科学院武汉）关键词鱼肝脏，线粒体，微量热学，热化学线粒体在能量代谢的过程中，除一部分能量用于合成ＡＴＰ外...     

负载咖啡因-活性炭新吸附材料对钼(VI)的吸附行为的研究

以生物碱（咖啡因）为衍生化试剂，用浸渍法使其负载于活性炭（ＡＣ）上，制成一种新的金属阴离子吸附材料———负载咖啡因－活性炭（ＣＡＣ）。用ＩＣＰ－ＡＥＳ研究了该吸附材料对金属阴离子［Ｍｏ７Ｏ２４］６－的吸附性能；考察了其化学稳定性；还研究了不同浓度硫酸和氨水对待测物吸附率和解脱率的影响及共存离子的干扰影响。