CuO/TiO2的制备及对NO＋CO反应性能的研究

以三种不同的TiO2为载体，负载6%CuO，在色谱-微反装置上考察了三种Cu6-Ti催化剂对NO＋CO反应的活性。结果表明，由于制备方法不同，活性差别很大，三者活性顺序依次为：Cu6-Ti(T)> Cu6-Ti(S)> Cu6-Ti(nm)，TiO2的比表面积及晶型对活性的影响不明显。H2-TPR结果表明，Cu6-Ti在整个TPR过程中出现了3或4个还原峰，表明有多种CuO物种存在。不同预处理Cu6-Ti的TPR显示，在反应中Cu物种可能以多种价态同时存在。NO-TPD结果亦证明，Cu6-Ti对NO＋CO的反应活性与NO在催化剂表面的解离难易密切相关，而与NO的吸附量关系不大。     

Synthesis and Characterization of PE-g-MA/MgAl-LDH Exfoliation Nanocomposite via Solution Intercalation

Anorgano modifiedMgAl layereddoublehydroxide (OMgAl LDH )wassuccessfullyexfoliatedinthexylenesolutionofpolyethylene grafted maleicanhydride (PE g MA )underre fluxingcondition .APE g MA/MgAl LDHexfoliationnano compositewasformedaftertheprecipitationofPE g MAfromthedispersionsystem .ThestructureandthermalpropertyofthePE g MA/MgAl LDHexfoliationnanocompositewerechar acterizedbyX raydiffraction (XRD ) ,transmissionelectronmicroscopy (TEM ) ,andthermogravimetryanalysis (TGA ) .The…     

MgCl2 Enhances Cluster Formation by Nanoscale Toroidal DNA Condensates

Multivalent cations can cause DNA to condense from its extended state in solution into high-density toroid-shaped particles. Developing methods to control the size and size distribution of DNA toroids is an important goal for the development of artificial gene delivery systems. Here we demonstrate that changes in salt conditions, prior to condensation by multivalent cations, can significantly affect DNA condensation. Specifically, millimolar concentrations of MgCl₂ are shown to cause the formation of toroid clusters, whereas NaCl at the same ionic strength does not.     

红四氮唑作为电化学嵌合剂的核酸杂交生物传感器

提出了一种以红四氮唑 (TTC)作为嵌合剂 ,采用石墨修饰电极监测核酸杂交过程和测定特定 DNA片段的灵敏的电化学方法 . TTC具有背景电流低 ,电活性强和对双链 DNA(ds DNA)选择性好等一系列优点 ,可在石墨电极表面形成 ds DNA-TTC层 .在电化学测定中 ,TTC的还原电流与靶 DNA浓度具有良好的线性关系 ,对 DNA的检测限可低达 6× 1 0 - 1 1 mol/L .     

Self aggregation of binary mixtures of sodium dodecyl sulfate and polyoxyethylene alkyl ethers in aqueous solution

The mixed micelles of sodium dodecyl sulphate (SDS) with Brij35 and Brij 97 were studied separately by fluorescence measurement using pyrene as fluorescent probe. In the range of 0–1.0 mole fraction (X) of added SDS to Brij solutions, the cmc value of the mixed micelles varies from 0.085 to 8 mmol with Brij 35 and 0.04 to 8 mmol with Brij 97. The aggregation number also changes. A measure of the stability of mixed micelles is also presented. The interaction parameter ₁₂ and the chain–chain contribution parameter (B₁) are extracted from the analysis of the results. This parameter B₁ is related to the standard free energy change associated with the introduction of one ionic species into a nonionic micelle coupled with the release of one nonionic species from the micelle. The clouding behaviour of Brij 97 in the presence of SDS was investigated and the associated thermodynamic parameters of clouding were generated and discussed.     

Spin-transition behaviour of transition metal complexes with 2,6-bis-(benzimidazol-2′-yl)-pyridine induced by deprotonation of the complex

Summary 2,6-bis-(Benzimidazol-2-yl)-pyridine (bzimpy = H₂ L) acts as a bidentate ligand when combining with transition metal ions. The complexes [M(bzimpy)₂](ClO₄)₂ (M = Fe²⁺, Mn²⁺, Zn²⁺, Co²⁺, and Ni²⁺) were obtained as solids. The protonation constants (logK) for the ligand and the complexes were evaluated in 30:70 (v/v) H₂O:EtOH at 293 K and at constant ionic strength of 0.12M KCl. Coordination of the ligand to the metal ions leads to an increase of acidity of the imino-hydrogen of the benzimidazole group of the ligand as a function of the complex stability. Deprotonation leads to a spin-state transition (intermediate spin-state low-spin) of the iron(II)-complex, followed by a shift of the metal-to-ligandcharge transfer band (MLCT) to lower energies (_max=563 to 580 nm). The d-d absorption bands are found to shift to higher energies and the low-spin isomer is favoured at room temperature. An opposite shift of theMLCT band (_max=563 to 557 nm) is observed when HClO₄ is added to the complex solution, rendering the high-spin state of the complex more favourable.On leave from the Chemistry Department, Jahangirnagar University, Dhaka, Bangladesh     

LaC_3~n(n=-1,0,+1)分子簇的理论研究(英文)

用密度泛函方法研究了ＬａＣ３ｎ（ｎ＝－１，０，＋１）分子簇的结构和稳定性，对这个四原子体系，提出了５种可能构型，其中３种具有Ｃ２ｖ对称性，２种为Ｃ∞ｖ对称性．在Ｃ２ｖ对称性结构中，其中１个为Ｌａ接在弯曲的Ｃ３链上，第２个是Ｌａ通过２个键与Ｃ３环相链，第３个是Ｌａ通过１个键与Ｃ３环相连；在Ｃ∞ｖ对称性中，第１个Ｌａ接在Ｃ３链的一端，而在第２个构型中，Ｌａ被插入在Ｃ３链中．结果表明，环状结构当Ｌａ接在弯曲的Ｃ３链上的是局域极小值并且最稳定     

The Antiepileptic Lamotrigine and Its Analogues: Comparative Theoretical Electronic Properties

Electronic properties of lamotrigine (LTG) and two analogues (A1 and A2) are compared through MOPAC-AM1 calculations. Two stable conformers of LTG are calculated to exist in agreement with X-ray crystallography. In the three compounds and the two conformers for each of them, the more favorable protonation sites are N₂ and N₄; these should then be the sites appropriate for interaction with a receptor, and group valence reinforces the supposition. The molecular electrostatic potentials show that a region between the two chlorine atoms in LTG could be the site for an electrostatic interaction with a corresponding site in the receptor. The fluorine atom in A1 would play an equivalent role. A simple model for LTG-receptor interaction is proposed.     

亮氨酸与异亮氨酸在金/银核-壳复合纳米粒子上的吸附状态

The Raman spectra and Surface enhanced Raman spectra (SERS) of leucine and isoleucine adsorbed on core-shell Au/Ag nanoparticles were obtained and assigned, and the different Raman peaks resulting from different vibrational models of the isomers忆groups were analysed. In Raman spectra, the leucine’s (ω(CH3)) is at 962, 945, 924 cm-1, (δas(CH3)) at 1408, 1454 cm-1; corresponding values for isoleucine are, 922 cm-1 and 1448, 1420, 1394 cm-1, respectwely. The difference in the peak positions of corresponding groups between leucine and isoleucine is more apparent in the SERS at acidic and basic conditions. The relationship between leucine and isoleucine’s concentration and SERS was interpreted preliminarily and the adsorption model on the core-shell Au/Ag nanoparticle surface was speculated.