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991.
A method for preparing Na2WO4-PAA-Glycerol photochromic films was reported. The film was composed of Na2WO4, PAA and Glycerol, which were coated on a glass substrate. The film turned blue in the sun, and bleached to transparent in the darkness. The UV-Visible spectra showed strong absorbance at 300~500 nm, and the ABS changed signifanctly at 500~800 nm. The film showed the best photochromic behavior when nNa2WO4nPAA is 4%~5%. The mechanism was suggested that after irradiation, poly tunstate produced by Na2WO4 and PAA formed the tungsten blues. The tungsten blues were bleached due to oxidation back to poly tunstate by oxygen. The film showed not only an excellent photochromism property with rapid response and good reversibility, but also the simple techniques and good stability.  相似文献   
992.
A fibrous sorbent possessing abundant micropore structure was firstly prepared via post-crosslinking reaction on the PP-ST-DVB original fiber. Its micromorphology and sorptive properties were investigated, and the results demonstrated that the novel fibrous hypererosslinked sorbent has narrow pore-size distribution, small average porous radius (1.90 nm), high specific surface area (362.31 m^2/g), and fine sorptive properties for small organic molecules.  相似文献   
993.
Conformations of p‐methacryloylaminophenylarsonic acid (p‐MAPHA) are determined through molecular mechanics and DFT/B3LYP calculations. Solvation effects are studied within the self‐consistent isodensity continuum model (SCI‐PCM). The stationary points were found to correspond to minima as verified by the analysis of vibrational frequencies in the molecule. The molecular optical absorption was obtained by using different solvent environments. The present results are in good agreement with the available experimental data. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002  相似文献   
994.
995.
Sixteen compounds containing the bicyclic moiety (3,8,10-trisubstituted 2,9-dioxo-5-thia-1,8-diazabicyclo[4.4.0]decane) were produced via solid-phase synthesis. Differing substitution at the 3- and 10-positions was used. These were analyzed using 2-D NMR techniques (ROESY) to determine the stereoselectivity of ring formation in the core heterocycle. Conformational analysis of the proposed transition state structure using Sybyl 6.8® was used to rationalize the stereochemical outcome of ring formation.  相似文献   
996.
The interaction between gatifloxacin mesylate (GM) and salmon sperm DNA was studied by fluorescence spectrometry and ultra‐violet (UV) spectrometry. Additions of salmon sperm DNA to GM solution resulted in its strong fluorescence quenching and UV absorbance decrease due to the strong interaction between GM and salmon sperm DNA. Both the maximum fluorescence emission wavelength and the maximum UV absorbance wavelength of GM did not change with the increasing concentration of salmon sperm DNA, indicating no intercalative binding existed between them. The Stern‐Volmer plot indicated that the fluorescence‐quenching constant at different temperatures or different salmon sperm DNA concentration ranges was different. Effects of ionic strength and I? on the fluorescence quenching of GM by salmon sperm DNA indicated that electrostatic interaction and groove binding coexisted between them.  相似文献   
997.
Poly(malachite green) film modified Nafion‐coated glassy carbon electrodes have been prepared by potentiodynamic cycling in malachite green solution. The pH of polymerisation solution has only minor effect on film formation. Electrochemical quartz crystal microbalance (EQCM) was used to monitor the growth of the poly(malachite green) film. Cyclic voltammogram of the poly(malachite green) film shows a redox couple with well‐defined peaks. The redox response of the modified electrode was found to be depending on the pH of the contacting solution. The peak potentials were shifted to a less positive region with increasing pH and the dependence of the peak potential was found to be 56 mV per pH unit. The electrocatalytic behavior of poly(malachite green) film modified Nafion‐coated glassy carbon electrodes was tested towards oxidation of NADH, dopamine, and ascorbic acid. The oxidation of dopamine and ascorbic acid occurred at less positive potential on poly(malachite green) film compared to bare glassy carbon electrode. In the case of NADH, the overpotential was reduced substantially on modified electrode. Finally, the feasibility of utilizing poly(malachite green) film electrode in analytical estimation of ascorbic acid was demonstrated in flow injection analysis.  相似文献   
998.
Dispersion of MoO3, NiO, ZnO on rutile TiO2 with low specific surface area was studied with Mercury Porosimeter, SEM, XPS and Ammonia Extraction method. The dispersion thresholds of MoO3, NiO, ZnO on three rutile TiO2 carriers were obtained with XPS, and com-pared with those on anatase TiO2 with high specific surf are area. Ammonia Extraction method was used to identify the surface oxide species interarting with support surface in different strength and it was found that the proportions of oxides that can not be extracted by ammonia extraction are different for MoO3, NiO and ZnO which are supported on rutile TiO2.  相似文献   
999.
UO2、UC2和UCO分子的结构和热力学性质   总被引:7,自引:0,他引:7  
用密度泛函B3LYP方法,计算了UO2、UC2和UCO分子的结构和热力学函数,计算了固体U的振动内能Ev、振动和电子熵Sev,以及U在不同气氛(O2、C2、CO)中形成UO2、UC2和UCO晶体的ΔHfΘ、ΔSfΘ和ΔGfΘ.结果表明,UO2晶体最稳定.  相似文献   
1000.
形态结构和光电特性对纳米TiO2光催化性能的影响   总被引:6,自引:0,他引:6  
采用sol-gel法制备了系列纳米TiO2光催化剂,运用X射线衍射、BET比表面测定、紫外漫反射吸收光谱和表面光电压谱等手段对催化剂进行表征,并以乙烯作为光催化反应的指标反应分子,研究了TiO2纳米晶的性质对于光催化活性的影响.随着焙烧温度的升高,TiO2的晶粒逐渐增大,比表面积下降,晶相由锐钛矿向金红石转变,其吸收带边与光伏响应阈值向长波方向移动,氧化-还原能力降低,降解乙烯的转化率迅速下降.  相似文献   
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