正已醇-邻、间、对二甲苯二元系固液相平衡

Melting temperatures have been measured and the solid-liquid phase diagrams constructed for 1-hexanol＋o-xylene, 1-hexanol＋m-xylene and 1-hexanol＋p-xylene. They are simple eutectic systems. Excess mole Gibbs free energies were calculated at 298.15K, showing larger positive deviations from ideal-solution behavior. The largest values of GmE are 711、 650 and 800 J•mol-1 for {o-C6H4(CH3)2＋C6H13OH}、 {m-C6H4(CH3)2 ＋ C6H13OH} and {p-C6H4(CH3)2＋C6H13OH} respectively.     

基于磁泳的生物分离分析技术

利用磁场诱导的微粒运动即磁泳对磁响应性粒子进行精细分离,是近年来发展起来的选择性分离细胞和高分子量核酸的有效技术。本文在阐明磁泳分离原理的基础上,介绍了磁泳分离的分流薄层分级技术、四极磁场流动分离技术和微芯片上的自由流磁泳分离技术的装置构造、工作原理及其在生物分离分析中的应用。     

真空下X2 (X=Cl、Br)与AgOCN气-固反应机理

在真空条件下完成了X2 (X=Cl、Br)与AgOCN间的气-固异相反应，利用紫外光电子能谱（PES）仪，探测与确定反应产物是XNCO (X=Cl、Br)，并推断其可能为一过渡态反应，生成中间络合物，新键产生与旧键断裂同时进行.     

螯合型二甘醇钛酸酯的合成及其催化性能研究

报导了两种新的螯合型二甘醇钛酸酯的合成方法，进行了ＩＲ和ＵＶ鉴定，并作为酯化反应催化剂催化合成了邻苯二甲酸二辛酯。研究了酯化反应转化率与反应时间、反应温度及催化剂用量的关系，探讨了催化剂结构与催化性能的关系。     

Impact of azaproline on Peptide conformation

The amino acid analog azaproline (azPro) contains a nitrogen atom in place of the C(alpha) of proline. Peptides containing azPro were shown to stabilize the cis-amide conformer for the acyl-azPro bond and prefer type VI beta-turns both in crystals and in organic solvents by NMR. The increased stability for cis-amide conformers was relatively minor with respect to the trans-conformers. Further, their conformational preferences were depended on solvent. To elucidate the impact of azPro substitution on amide cis-trans isomerism and peptide conformation, this paper reports ab initio studies on azPro derivatives and a comparison with their cognate Pro derivatives: 1-acetyl-2-methyl pyrrolidine (1), 1-acetyl-2-methyl pyrazolidine (2), Ac-Pro-NHMe (3), Ac-azPro-NHMe (4), Ac-azPro-NMe(2) (5), Ac-azAzc-NHMe (6), and Ac-azPip-NHMe (7). Conformational preferences were explored at the MP2/6-31+G** level of theory in vacuo. Solvation effects for 1 and 2 were studied implicitly using the polarizable continuum model and explicitly represented by interactions with a single water molecule. An increase in the conformational preference for the cis-amide conformer of azPro was clearly seen. An intramolecular hydrogen bond occurred solely in the trans-amide conformer that reduced the preference for the cis-conformer by 2.2 kcal/mol. The larger ring homolog aza-pipecolic acid (azPip), in which this internal hydrogen bond was diminished, significantly augmented stabilization of the cis-amide conformer. In aqueous solution, the preference for the cis-amide conformers was greatly reduced, mainly as a result of interaction between water and the lone pair of the alpha-nitrogen in the trans-amide conformer that was 3.8 kcal/mol greater than that in the cis-conformer. In the azPro analog, the energy barrier for cis-trans amide isomerization was 6 kcal/mol less than that in the cognate Pro derivative. Because the azPro derivatives can stabilize the cis-amide bond and mimic a type VI beta-turn without incorporation of additional steric bulk, such a simple chemical modification of the peptide backbone provides a useful conformational constraint when incorporated into the structure of selected bioactive peptides. Such modifications can scan receptors for biological recognition of reverse turns containing cis-amide bonds by the incorporation of type VI beta-turn scaffolds with oriented appended side chains.     

高效液相色谱检测Zn（Ⅱ）、Cd（Ⅱ）、Co（Ⅱ）、Pb（Ⅱ）、Ni（Ⅱ）、Cu（Ⅱ）、Hg（Ⅱ）

用双-(2-羟乙基)二硫代甲酸铵(HEDC)在反相液相色谱中作检测某些金属离子的衍生化试剂，HEDC的金属螯合物微溶于水，可直接水样注射于C18柱中进行检测，范围为0．006～10mg／L相对偏差1％～2％，检测波长254nm，金属汞的整合物在HPLC分析前进行浓缩富集检测限可低至0．06～25μg／L，相对偏差小于2％。     

Stoichiometric and catalytic oxidations of alkanes and alcohols mediated by highly oxidizing ruthenium-Oxo complexes bearing 6, 6'-dichloro-2,2'-bipyridine

The ruthenium(II) complex cis-[Ru(6, 6'-Cl(2)bpy)(2)(OH(2))(2)](CF(3)SO(3))(2) (1) is a robust catalyst for C-H bond oxidations of hydrocarbons, including linear alkanes, using tert-butyl hydroperoxide (TBHP) as terminal oxidant. Alcohols can be oxidized by the "1 + TBHP" protocol to the corresponding aldehydes/ketones with high product yields at ambient temperature. Oxidation of 1 with Ce(IV) in aqueous solution affords cis-[Ru(VI)(6, 6'-Cl(2)bpy)(2)O(2)](2+), which is isolated as a green/yellow perchlorate salt (2). Complex 2 is a powerful stoichiometric oxidant for cycloalkane oxidations under mild conditions. Oxidation of cis-decalin is highly stereoretentive; cis-decalinol is obtained in high yield, and formation of trans-decalinol is not observed. Mechanistic studies showing a large primary kinetic isotope effect suggest a hydrogen-atom abstraction pathway. The relative reactivities of cycloalkanes toward oxidation by 2 have been examined through competitive experiments, and comparisons with Gif-type processes are presented.     

Activity concentrations of 210Po in the soft parts of cockle (Anadara granosa)at Kuala Selangor, Malaysia

Polonium-210 has been measured in the soft parts of Anadara granosa purchased at Kuala Selangor, West Coast of Malaysia in August 2001, April 2002 and September 2002. It is shown that ²¹⁰Po is non-uniformly distributed within cockles of various sizes (i.e., 2.5, 3.0, 3.5 and 4.0 cm of shell length) and the concentration of ²¹⁰Po in the soft parts of cockle was significantly different (p<0.05) due to sampling date. The highest value was observed in the smallest cockle with a shell length of 2.5 cm (411.6±26.16 Bq/g dry wt.). It is clear that there is an allometric relationship between ²¹⁰Po activity concentration and individual cockle weight. This may reflect on the differences of metabolic rate and growth age of cockles. The mean activity concentration of ²¹⁰Po measured in Kuala Selangor filtered water were 1.75±0.17, 0.79±0.08 and 1.13±0.20 Bq/kg for August 2001, April 2002 and September 2002, respectively. The yield concentration factors for ²¹⁰Po in the soft parts of cockles varies from 27.3^. 10³ to 106.9^. 10³. This revised version was published online in July 2006 with corrections to the Cover Date.     

EPR studies of isotopic exchange involving adsorbed oxygen species on MgO

In the EPR spectra of ¹⁷O₂^? adsorbed on MgO, the hyperfine lines due to ¹⁷O(I = $\text{5}\text{2}$) have been used to monitor the isotopic exchange with gas phase oxygen. The predicted behaviour of the different possible mechanisms (place exchange and/or isotopic exchange) is compared with the experimental results which show that, on MgO at room temperature, isotopic exchange occurs via an intermediate species which is tentatively identified as O₄^?.     

质谱法测定冰毒

采用直接进样化学电离（ＣＩ）质谱法，配合电子轰击（ＥＩ）及气相色谱－质谱联用（ＧＣ／ＭＳ）技术，测定了冰毒及其制备过程中的副产品与中间产物，为刑侦破案提供了依据。