TritonX—100存在下偶氮氯膦Ⅲ分光光度法测定锰化合物中的微量钙

研究了钙与偶氮氯膦Ⅲ（ＣＰＡⅢ）的配位显色反应。在非离子型表面活性剂ＴｒｉｔｏｎＸ－１００存在下，于ｐＨ２．５的邻苯二甲酸氢钾－盐酸缓冲溶液中，钙可与ＣＰＡⅢ形成１∶２稳定的蓝色配合物，其最大吸收波长为６５６ｎｍ，表观摩尔吸光系数为２．８４×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，钙量在０～３０μｇ／２５ｍＬ范围内服从比尔定律。本法已用于锰化合物中微量钙的测定。     

Characterization of self-assembled monolayers of thiols on Au(111)

Self-assembled monolayers (SAMs) of n-butanethiol, n-dodecanethiol and their equimolar mixture on Au(111) were prepared and characterized by ellipsometry, contact angle measurement, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results revealed that these SAMs are oriented ultrathin films with the thickness of nanometer scale, and the SAMs were influenced by the molecular chain length, the lattice orientation and cleanliness of the substrates. The surface of the longer chain SAM is hydrophobic. The thicknesses of three SAMs of n-butanethiol, n-dodecanethiol and their mixture revealed by ellipsometry and XPS are about 0.59 - 0.67nm, 1.60- 1.69 nm and 1.23 - 1.32nm, respectively. AFM images further demonstrated that the SAM formed by the mixture has some microdomains with two different thicknesses.     

[Ce(NO3)5H2O]·(C3H5N2)2的合成、晶体结构及热分析

Colorless crystal, [Ce(NO₃)₅H₂O]·(C₃N₂H₅)₂, has been obtained from the reaction of Ce(NO₃)₃ with imdazole in the aqueous solution and its crystal structure has been determined by single crystal X-ray diffraction techniques.The crystal belongs to triclinic, space group P1. The cell parameters are: a = 0.7489(1) um, b = 0.7914(2) nm, c = 1.8139(3) nm, a = 89.39(2)°, β = 89.37(l) °,γ = 63.18(2)°, Dc = 2.1g·cm^-3, Z = 2, R = 0.0319.In the compound, all of five nitrates are bidentate and one molecule of water is monodentate, the coordination number of Ce (Ⅲ) is 11.The processes of thermal decomposition of the compound was proposed by its TGcurve.     

钴与2-[2-(5-溴苯并噻唑)偶氮]-5-二甲氨基苯甲酸显色反应的分光光度法研究

本文合成丁新试剂2-[2-(5-溴苯并噻唑)偶氮-5-二甲氨基苯甲酸(5-Br-BTAMB)。研究了在表面活性剂存在下它与钴的显色反应。发现 TritonX-100存在下,钴与5-Br-BTAMB在 pH6.0～8.5范围内形成稳定的蓝色配合物。其最大吸收峰位于660nm。表观摩尔吸光系数为1.22×10~5L·mol·cm~(-1)。配合物中钴与5-Br-BTAMB 的组成比为1:2.钴浓度在0～12μg/25ml 范围内呈良好的线性关系。在硫脲存在下,该方法具有良好的选择性,用于测定含钴分子筛和 V_(B12)中微量钴。结果令人满意。     

过氧化物模拟酶生物传感器—二茂铁衍生物为介体

本文用三种二茂铁衍生物－双羟基乙基二茂铁、单羟基乙基二茂铁和羧基二茂铁为介体，在过氧化物模拟酶－ｍｅｓｏ－四（４－磺基苯）卟啉锰存在下，检测过氧化氢，以双羟基，单羟基乙基二茂铁为介体时，获得了良好的结果。     

低初始振动激发van der Waals分子HeI_2振动预离解三维含时波包动力学研究

用含时黄金规则波包法,计算了低初始振动激发HeI_2分子振动预离解总和分衰变宽度,寿命和速率及它们随初始振动态υ的变化.计算结果与实验外推数据符合得相当好.计算所需很短的波包总传播时间(不超过1ps)是由离解碎片在振动去激发绝热势能面(υ-1)上驻留时间决定的.较强的终态相互作用的影响是很重要的.预言并解释了终转动态分布随着υ的移动而改变的动力学规律.     

第32届中国化学奥林匹克(决赛)试题解析(三)

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Multi-dimple phenomena in TEHL point contacts

Theoretical analysis and experimental measurement of the multiple dimples in thermal elastohydrodynamic lubrication (TEHL) point contacts have been carried out. Good agreement is found between the theoretical and experimental results. A thermal multi-spike theory is proposed to explain the multi-dimple phenomena.     

溶有增粘树脂的丙烯酸酯乳液共聚及压敏胶的性能

用一步法将溶有松香或氢化松香的丙烯酸酯单体进行乳液共聚合时，由于增粘树脂分子的自由基链转移作用使单体的转化率明显降低．先将大部分丙烯酸酯单体进行乳液共聚制得种子乳液，再将溶有增粘树脂的剩余丙烯酸酯单体加到种子乳液中进行第二步乳液共聚合，可显著提高单体的总转化率．用ＴＥＭ对分步聚合所得复合乳液的粒子形态进行了观察并对第二步乳液共聚合的机理进行了讨论．用分步乳液共聚合的方法制得的增粘树脂 丙烯酸酯复合乳液共聚物的压敏胶粘性能较一步法有很大的提高．     

1-甲基-3,5-二苯基吡唑啉在氯化铜催化下的氧化脱氢反应——Ⅰ.反应过程中形成的配合物

我们曾用1-甲基-3,5-二苯基吡唑啉(H_2MDPP)在铜、钴和铬等六种过渡金属的氯化物的存在下与氧气作用,制得了1-甲基-3,5-二苯基吡唑(MDPP),反应式如下: