Crystal structure and luminescence property of ternary terbium p-aminobenzoic acid complexes with different second ligands

Ternary terbium complexes with p-aminobenzoic acid (HL), [TbL₃(DMSO)(H₂O)]₂ (1), [TbL₃(DMF)(H₂O)]₂ (2) and [TbL₃(Bpy)(H₂O)]₂·2H₂O (3) (DMSO=dimethyl sulfoxide, DMF=N, N- dimethylformamide, Bpy=2, 2′- bipyridyl) have been synthesized, and their crystal structures determined. The luminescence properties of these complexes, including both the emission quantum yield and the fluorescence lifetime, have been investigated. The effect of a second ligand on the crystal structure and luminescence property of the ternary terbium p-aminobenzoic acid complexes, and the relationship between luminescence properties and crystal structure, including coordination mode of the L⁻ ligand and the characteristics of a second ligand, are discussed.     

Electrodeposition and stripping process by long optical pathlength potential-step transmission chronoabsorptometry

Based on the transmittance-averaged rather than absorbance-averaged model of long optical pathlength transmission spectroelectrochemistry, a reasonable theoretical model for potential-step electrodeposition and stripping process has been developed. It can accurately predict the stripping-chronoabsorptometric waveform with a peak absorbance with respect to the time rather than that with no peak but only a theoretical maximum absorbance at the initial stage of the stripping process. Cu(II) in NH(3) . H(2)ONH(4)Cl supporting electrolyte is utilized to verify the theory. With this anodic stripping spectroelectrochemical method, a detection limit of ca 0.01mM without stirring or ca 0.002mM under stirring during deposition can be achieved. An application in the analysis of copper in practical samples is presented.     

溶液的pH值对纳米CeO2晶粒形貌及形成机制的影响

以亚硝酸铈盐和氨水沉淀法合成了二氧化铈纳米粒子. 通过对溶液pH值的调节制备出了形貌各异的纳米CeO2晶粒. TEM和BET结果表明 酸性条件下, 得到的是球形的纳米CeO2晶粒且其比表面为148.1944 m2·g-1;中性时, CeO2晶粒的形貌为球形和棒状的混合形, 比表面为114.7975 m2·g-1;而碱性环境下, 易得到棒状的、比表面为106.2465 m2·g-1 的CeO2晶体. 另外还对各种形貌产物的形成机制进行了研究.     

稀土-二甲酚橙络合物的胶束液相色谱分离与测定

本文应用一种新的高效液相色谱-胶束液相色谱法,在Shim-Pack CLC-ODS(150mm×6.0mm)色谱柱上,用含1.6×10~(-2)mol/L的CTMAB和pH=7.40的三-(羟甲基)-氨基甲烷缓冲液的甲醇/水(5:95)作流动相,对15种稀土元素-二甲盼橙络合物进行分离,取得了较满意的结果。     

A nonlinear regression model applied to kinetic studies of ester hydrolysis with a surface acoustic wave sensor

A non-linear regression model was derived for the simultaneous determination of the rate constant in alkaline hydrolysis of esters and the initial concentration of esters based on the linear relationship between the frequency response of the surface acoustic wave sensor system and the conductivity of the solution. The model was tested theoretically and experimentally with the methyl-, ethyl-, and n-propyl-acetate systems. The corresponding rate constants estimated at 25 degrees C are 0.147, 0.103 and 0.0671 respectively.     

Alloyed semiconductor quantum dots: tuning the optical properties without changing the particle size

Alloyed semiconductor quantum dots (cadmium selenium telluride) with both homogeneous and gradient internal structures have been prepared to achieve continuous tuning of the optical properties without changing the particle size. Our results demonstrate that composition and internal structure are two important parameters that can be used to tune the optical and electronic properties of multicomponent, alloyed quantum dots. A surprising finding is a nonlinear relationship between the composition and the absorption/emission energies, leading to new properties not obtainable from the parent binary systems. With red-shifted light emission up to 850 nm and quantum yields up to 60%, this new class of alloyed quantum dots opens new possibilities in band gap engineering and in developing near-infrared fluorescent probes for in vivo molecular imaging and biomarker detection.     

Analyzing functional similarity of protein sequences with discrete wavelet transform

This paper applies discrete wavelet transform (DWT) with various protein substitution models to find functional similarity of proteins with low identity. A new metric, 'S' function, based on the DWT is proposed to measure the pair-wise similarity. We also develop a segmentation technique, combined with DWT, to handle long protein sequences. The results are compared with those using the pair-wise alignment and PSI-BLAST.     

基于支持向量机的羰基化合物红外光谱研究

设计了一个4层分等级分类系统，通过支持向量机技术对羰基化合物的红外光谱成功地进行了信息分类和提取，并与人工神经网络进行比较，结果表明：支持向量机对羰基类化合物红外光谱分类效果优于人工神经网络；另外详细探讨了表征酰胺类化合物的特征光谱峰片段对识圳伯仲叔酰胺的影响，证明了酰胺的N-H伸缩振动峰对识别伯仲叔酰胺贡献最大，为构建红外光谱智能解析系统提供了定量依据。     

几种螯合剂解镍致小鼠胰脏毒作用比较

小鼠腹腔注射氯化镍溶液(5 mg Ni/kg)染毒，观察了N-苯甲基-D-葡糖氨基二硫代甲酸钠(BGD)、二乙氨基二硫代甲酸钠(DDTC)、二羟乙氨基二硫代甲酸钠(DHED)及meso-2，3-二巯基丁二酸钠(DMSA)等螯合剂对镍致小鼠胰脏毒性的解毒作用。镍染毒后引起小鼠胰脏胰蛋白酶活性升高和羧肽酶A活性降低以及组织中镍、钙、锌浓度增加；镍染毒30 min和24 h后进行各螯合剂治疗(剂量均为400 μmol/kg)，BGD、DDTC和DMSA可明显抑制上述变化，其中BGD解镍毒效果最好、自身毒性最小、对镍致小鼠胰脏毒性有更好的解毒作用。