乌鲁木齐地区土壤对SO4^=的吸附动力学研究

本文对乌鲁木齐土壤吸附ＳＯ４＾＝进行了动力学研究。实验结论与Ｆｒｅｕｎｄｌｉｃｈ和Ｔｅｍｋｉｎ等温吸附数学模型拟合较好。     

β－苯基丙烯酸钕配合物的单晶制备性质研究和晶体结构（Ⅰ）配合物的单晶制备及配位性质

本文用复分解法并利用水、乙醇和苯三元混合溶剂制备了β－苯基丙烯酸的稀土配合物单晶．用红外光谱和核磁共振谱研究了配合物中Ｎｄ－Ｏ键的成键性能以及羧基的配位性质．     

一种7-羟基四氢喹喔啉-6-甲醛衍生物对H2S的比色和荧光识别

本文利用1,4-二乙基-7-羟基四氢喹喔啉-6-甲醛与2-甲基苯并噻唑盐反应制备了荧光探针L,并对其结构进行了表征。实验结果表明,探针L在DMSO溶液中对H_2S具有快速荧光"关-开"响应以及高选择性和较好的抗干扰能力,检测限为2. 5×10~(-6)mol/L。在365nm紫外灯照射下,L的荧光颜色由无荧光变成黄绿色强荧光;此外,加入H_2S后探针L的DMSO溶液颜色由蓝紫色变为无色,通过裸眼即可识别H_2S。     

用尖晶石型化合物NiCo2O4和复合镀技术制备析氧电极

为减少析氧电位、提高电极的稳定性、降低能耗和成本，人们一直在努力合成各种过渡金属复合氧化物作为析氧的电催化材料［１］．研究表明，尖晶石型化合物ＮｉＣｏ２Ｏ４对氧的析出有较高的催化活性［２］．但因其制备方法多为喷涂热解法，需４００℃以上温度，因此易发生...     

Rotational reorientation dynamics of oxazine 750 in polar solvents

The rotational reorientation dynamics of oxazine 750 (OX750) in the first (with pump pulse at 660 nm) and a higher excited state (with pump pulse at 400 nm) in different polar solvents have been investigated using femtosecond time-resolved stimulated emission pumping fluorescence depletion (FS TR SEP FD) spectroscopy. In both excited states, three different anisotropy decay laws have been observed for OX750 in different solvents. Only in acetone and formamide could the anisotropy decays of OX750 be described by single-exponential functions, whereas the anisotropy decays have been found to exhibit biexponential behavior in other solvents. The slower anisotropy decay observed in all of the solvents has been assigned to the overall rotational relaxation of OX750 molecules, and a quantitative analysis of this time constant has been performed using the Stokes-Einstein-Debye hydrodynamic theory and the extended charge distribution model developed by Alavi and Waldeck. In both methanol and ethanol, a faster anisotropy decay on the order of picoseconds and a slower anisotropy decay on the hundreds of picoseconds time scale are observed. The most likely explanation for the faster anisotropy involves the rotation of the transition dipole moment in the excited state of OX750 resulting from the electron transfer (ET) reaction taking place from the alcoholic solvents to the OX750 chromophore. As a possible explanation, the wobbling-in-the-cone model has been used to analyze the biexponential anisotropy decays of OX750 in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The observed faster anisotropy decays on the hundreds of femtoseconds time scale in DMF and DMSO are ascribed to the wobbling-in-the-cone motion of the ethyl group of OX750, which is sensitive to the strength of the hydrogen bond formed between the solvent and the protonation site of OX750.     

锂离子电池正极材料的热稳定性

运用热分析方法定性研究了固态LiClO4和LiClO4电解液的热稳定性能,进而对比分析了3种常见锂离子电池正极材料LiNi0.85Co0.15O2,LiMn2O4和LiFePO4的热稳定性能.结果表明,在200~250℃温度范围内,LiClO4电解液不会影响反应体系.充电状态下,Li0.18Ni0.85Co0.15O2与电解液发生反应的温度集中在215℃左右;Li0.15Mn2O4与电解液发生反应的起始温度约为220℃,主要反应集中在250℃左右;Li0.17FePO4与电解液反应主要集中在230℃,但起始反应温度要高于Li0.15Mn2O4,显示出更好的热稳定性.因此,3种材料热稳定性由强到弱的顺序为:LiFePO4,LiMn2O4,LiNi0.85Co0.15O2.     

Rhodium(III)-catalyzed cyclization-olefination of N-acetoxyl ketoimine-alkynes

N-Acetoxyl ketoimine-alkynes undergo Rh(III)-catalyzed oxidative olefination to afford (2-acetoxymethyl)isoquinolines bearing an ortho-olefinated aryl group via a sequence that involves (1) Rh(III)-catalyzed alkyne cyclization with intramolecular 1,3-acetoxyl migration and (2) isoquinoline-directed ortho C-H olefination.     

Study of the molecular configuration and the dipole moment in fluorinated liquid crystals

We have investigated the relationship between the molecular configuration and dipole moment of some fluorinated liquid crystals (LCs). The geometries of the molecules were preliminarily optimized at empirical AM1 and then were further optimized at B3LYP/6‐31G(d) level. The dipole moment has been calculated. It is strongly influenced by the position and number of fluorine substituents in the benzene ring of the molecule. The polarizability, mean polarizabilities, and anisotropic polarizability of the phenylbicyclohexane (PBC) fluorine substituents are also given and discussed. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

非线形CS2 分子单重态和三重态的密度泛函理论

应用密度泛函理论 (DFT)的B3LYP和B3PW91两种方法 ,在 6 3 11+G 和aug cc pVTZ基组水平上 ,分别优化了CS2 可能存在的非线形单重态和三重态构型 ,在全局势能面上共发现 3个单重态 (电子态 1 A1 )和 5个三重态 (电子态分别为 3A2 、3B2 和 3B2 )的非线形CS2 异构体 ,正则振动频率分析证明所得到构型均是位能面上的极小 .计算所得CS2 异构体的相对能量顺序为 4t3B2 相似文献   

水杨酸锌的热分解反应机理

采用固相反应法合成了水杨酸锌，测定了其ＴＧ和ＤＴＡ曲线．用红外光谱、粉末Ｘ射线衍射、气相色谱和质谱法表征了各步热分解产物，研究了其热分解反应机理．整个热分解过程分两步进行：（ＨＯＣ６Ｈ４ＣＯ２）２Ｚｎ→（ＯＣ６Ｈ４ＣＯ２）Ｚｎ→ＺｎＯ．第二步热分解的气相产物有苯酚、二苯并呋喃和氧杂蒽酮等．