Formation of ring calcium oxalate patterns induced by domains in DPPC Langmuir-Blodgett films

The ring patterns of calcium oxalate crystals were induced by domains in Langmuir-Blodgett （LB） films of dipalmitoylpho- sphatidylcboline （DPPC）. The result was explained by the defects at the ring boundaries of liquid condensed （LC） and liquid expanded （LE） phases of LB film. These boundaries could provide less free energy and much more nucleating sites for COM crystals.     

2-乙基己基磷酸单(2-乙基己基)酯萃淋树脂分离-火花源质谱法测定高纯氧化镱中痕量稀土杂质

本文采用萃取色谱法以2-乙基已基膦酸单(2-乙基已基)酯(P_507)萃淋树脂为固定相,以HCI-NH_4CI体系为淋洗液,研究了99.999%~99.9999%的高纯Yb_2O_3中稀土杂质和Yb基体的分离条件,将杂质淋洗液富集于复合螯合剂-活性碳上,经灼烧灰化后制成样品电极,进行质谱测定.测定下限达 0.01~0.05 μg/g,可用于高纯 Yb_2O_3中杂质的测定.回收率在80%以上.     

毒素蛋白ColicinE1与磷脂膜相互作用的荧光光谱研究临界摩尔比的测定

磷脂－蛋白相互作用的临界摩尔比是研究膜脂－蛋白相互作用的重要参数．本文利用荧光光谱技术首次测定了毒素蛋白ＣｏｌｉｃｉｎＥ１在不同条件下与不同磷脂膜相互作用的临界摩尔比并通过临界摩尔比的变化讨论了插膜蛋白与磷脂膜相互作用的规律，为进一步探讨毒素蛋白的插膜机制提供了重要的基础     

W／O型微乳液中超氧化物阴离子的产生——微环境中SOD酶活性测定方法 …

分别在水溶液中和W／O型CTAB／正戊醇／异辛烷／水微乳液体系中研究了测定SOD酶活性的邻苯三酚法,发现在反向微乳液中,"小水池"的低介电常数和pH抑制了底物超氧化物阴离子O2-·的产生．只有提高外加缓冲液的pH或"小水池"的水化度,才能得到所需浓度的O2-·,从而初步解决了在微乳液中SOD作用底物的产生问题,为在微乳液中准确测定SOD酶活性创造了条件．     

Aggregation of sodium 1-(n-alkyl)naphthalene-4-sulfonates in aqueous solution: micellization and microenvironment characteristics

In aqueous solution, the micellization and microenvironment characteristics of the micelle assemblies of three anionic surfactants, sodium 1-(n-alkyl)naphthalene-4-sulfonates (SANS), have been investigated by steady-state fluorescence and time-resolved fluorescence decay techniques using pyrene, Ru(bpy)3(2+), and 1,6-diphenyl-1,3,5-hexatriene as fluorescence probes. The critical micelle concentrations (cmc's), effective carbon atom numbers (neff's), hydrophilic-lipophilic balances (HLBs), mean micelle aggregation numbers, micropolarities, and microviscosities of these surfactant micelles have been determined. The logarithmic cmc of the alkylnaphthalene sulfonates decreases linearly with an increase in the neff. The logarithmic aggregation number of the alkylnaphthalene sulfonates increases linearly with an increase in the neff. However, in contrast to the alkylsufonates and the alkylbenzene sulfonates, the aggregation for these alkylnaphthalene sulfonate molecules is less sensitive to the increase in the neff. The micropolarity of these alkylnaphthalene sulfonate micelles is less sensitive to the increase in the alkyl chain length and is lower than that of sodium dodecyl sulfate (SDS). The microviscosity of these alkylnaphthalene sulfonate micelles increases with an increase in the alkyl chain length and is lower than those of nonionic surfactants and zwitterionic surfactants. These results suggest that naphthyl rings have a notable effect on the micellization of SANS.     

Two new megastigmane O-glucopyranosides from the leaves of Broussonetia papyrifera

Two new megastigmane O-glucopyranosides,named (2R,3R,5R,6S,9R)-3-hydroxy-5,6-epoxy-β-ionol-2-O-β-D-glucopyrano- side(1) and (2R,3R,5R,6S,9R)-3-hydroxyl-5,6-epoxy-acety-β-ionol-2-O-β-D-glucopyranoside(2) together with six known mega- stigmanes,were isolated from the leaves of Broussonetia papyrifera (Linn.) Vent.Their structures were established by chemical methods and spectroscopic techniques including 2D NMR.     

Rapid simultaneous determination of four anthracene derivatives using a single non-linear variable-angle synchronous fluorescence spectrum

A rapid, simple and inexpensive spectrofluorimetric method has been developed for the simultaneous identification and quantification of anthracene (ANT), 9,10-dimethylanthracene (DIM), 2-aminoanthracene (AMI) and dibenz[ah]anthracene (DIB). A well-resolved spectrum for the mixture of these four compounds is obtained based on a single non-linear variable-angle synchronous scanning. The linear concentration ranges are 10-1,000, 5-500, 50-1,000 and 10-200 ng mL(-1) for ANT, DIM, AMI and DIB, respectively, at lambdaex/lambdaem = 358/380, 399/408, 414/465 and 298/394 nm, respectively. The analyses are performed in cyclohexane. Recoveries of 90.0-111.0% in synthetic mixtures are obtained. The detection limits are 2.0 ng mL(-1) for DIM, 2.7 ng mL(-1) for ANT, 15.8 ng mL(-1) for AMI and 4.2 ng mL(-1) for DIB. The method has also been applied to several real water samples with satisfactory results.     

Studies of synergism for lowering dynamic interfacial tension in sodium alpha-(n-alkyl) naphthalene sulfonate/alkali/acidic oil systems

Alkylnaphthalene sulfonates with high purity were selected as model components to research synergism for lowering interfacial tension (IFT) in surfactant/alkali/acidic oil systems. The dynamic IFTs between alkylnaphthalene sulfonates with different alkyl chain length and n-decane, oleic acid model oil, or Shengli crude oil were measured. The results showed that the alkylnaphthalene sulfonates with different alkyl chain lengths had different synergism with different acidic components and their ionized acids under the same conditions. The synergism for lowering dynamic IFT in alkylnaphthalene sulfonate/alkali/acidic oil systems was controlled by alkylnaphthalene sulfonate concentration, alkyl chain length, alkali concentration, alkali type, and oleic acid concentration: optimal physicochemical conditions were necessary to the best synergism. This indicates that the synergism among added surfactant acidic components in crude oil and their ionized acids is controlled by the ratio of their interfacial concentrations.     

塔板理论对柱内和柱外浓度分布曲线的描述

使用Visual Basic和QBasic程序，分别在Excel和DOS上，在不做任何化简的情况下，对塔板理论描述的柱内和柱外组分浓度分布进行了研究。发现符合线性分配的样品组分在色谱柱内存在3种不同的浓度分布形态，在色谱柱外则都是拖尾峰形态。分析了不同分配比对柱内和柱外浓度分布曲线最高点和次高点的影响。     

羧甲基壳聚糖衍生物及其振动光谱的理论研究

用量子化学从头算STO 3G法研究了羧甲基壳聚糖及其衍生物的结构和稳定性，计算结果表明:1)壳聚糖单体经羧甲基化后，得到2种可能的产物，其中羧甲基在壳聚糖单体2位氨基上的取代产物较6位羟基上的取代产物稳定； 2)以羧甲基壳聚糖为母体经加成反应，得到羧甲基壳聚糖衍生物（2 羟基 3 丁氧基）丙基 羧甲基壳聚糖的2个异构体， 其中构型1更稳定.在优化构型的基础上，计算所得的构型1的振动光谱与实验结果相吻合.