The electrodeposition of antimony in alkaline solutions containing xylitol was investigated using cyclic voltammetry,linear sweep voltammetry and chronoamperometry.The antimony electrodeposition and the chemical stabi...The electrodeposition of antimony in alkaline solutions containing xylitol was investigated using cyclic voltammetry,linear sweep voltammetry and chronoamperometry.The antimony electrodeposition and the chemical stability of xylitol in alkaline solutions were studied by cyclic voltammetric technique.Apparent activation energy,apparent transfer coefficient and exchange current density were obtained by linear sweep voltammetric technique.Initial stages of antimony electrocrystallization were determined by chronoamperometry.Xylitol in alkaline solutions exhibits high chemical stability and there is no redox in solutions when the potential ranges from-1.20 V to ＋0.60 V（vs Hg/HgO）.There is no other redox reaction but hydrolysis occurring on stainless steel in the potential range of-1.75 V to 1.25 V（vs Hg/HgO） while the xylitol decomposition maybe take place on antimony electrode when potential is more negative than-1.70 V（vs Hg/HgO）.Cyclic voltammograms with different scan rates indicate that the antimony electrodeposition process is an electrocrystallization which is a completely irreversible electrode process.The apparent activation energy,apparent transfer coefficient and exchange current density were calculated to be 46.33 kJ/mol,0.64 and 4.40×10-6 A/m2,respectively.The analyses of the chronoamperometric responses support the view of a three-dimensional growth under progressive nucleation.The average diffusion coefficient of antimony was calculated to be 1.53×10-6 cm2/s.展开更多
Growth and crystallization of titanium anodized films were studied by performing the anodization of the sputter-deposited titanium samples under cyclic voltammetry （CV） mode at very low potentials. The surface featu...Growth and crystallization of titanium anodized films were studied by performing the anodization of the sputter-deposited titanium samples under cyclic voltammetry （CV） mode at very low potentials. The surface features, crystalline behaviors and chemical compositions of the formed anodic oxide layers were detected by AFM, SE and XPS. It was found that the structure of the titanium anodized films is crystalline, even though the maximum oxidation potential （（Pmax） is very low （as low as 1000 mY）. Both enlarging the applied voltage and reducing the potential scanning rate are beneficial for the growth and crystallization of titanium oxide films. It was thought that the internal compressive stress, other than the local joule heating accepted for many researchers, is the main force of stimulating the crystallization of anodic titanium oxide films at very low potentials.展开更多
Antofloxacin free base is prepared from antofloxacin hydrochloride by removing hydrogen chloride. Its crystal is obtained by slow evaporation of an acetonitrile-methanol mixed solution. Single-crystal X-ray diffractio...Antofloxacin free base is prepared from antofloxacin hydrochloride by removing hydrogen chloride. Its crystal is obtained by slow evaporation of an acetonitrile-methanol mixed solution. Single-crystal X-ray diffraction reveals that the crystallography belongs to a triclinic PI space group with cell parameters： a = 0. 663 07（13） nm, b = 0. 898 39（18） nm, c = 1. 569 0（3） nm, α = 75.12（3）°,β = 87.92（3）°, γ = 77.57 （3）°. Antofloxacin shows no fluorescence in solution, but the crystalline state emits strong green light at 510 nm under the excitation of 360 nm, indicating a fluorescence enhancement induced by aggregation. It demonstrates that intermolecular packing and interaction in the crystal lead to the improved fluorescence quantum yield. These results provide important intbrmation for the further exploration of the structure-activity relationship of antofloxacin and the development of new drugs.展开更多
The analysis of solar cell performance has been done by simulating the external I-V characteristics of n +/p/p + single crystal silicon solar cell under high light intensity and 1.5 air mass (AM). This method allows t...The analysis of solar cell performance has been done by simulating the external I-V characteristics of n +/p/p + single crystal silicon solar cell under high light intensity and 1.5 air mass (AM). This method allows the maximization of solar cell efficiency. To fabricate low-cost n +/p/p + single crystal silicon solar cells, solid source of doped phosphorous and boron was used.展开更多
N,N-Dimethylamphetamine （DMA） is a methamphetamine （MA） analog and considered as an amphetamine-derived designer drug. In this study, a method of gas chromatography-mass spectrometry （GC-MS） combined with nuclea...N,N-Dimethylamphetamine （DMA） is a methamphetamine （MA） analog and considered as an amphetamine-derived designer drug. In this study, a method of gas chromatography-mass spectrometry （GC-MS） combined with nuclear magnetic resonance spectroscopy （1H and 13C NMR） was developed for the identification of dimethylamphetamine in a suspect exhibit. The results showed that purity of this sample was above 99% by GC-MS area normalization. Therefore, it could be used as a dimethylamphetamine reference substance in drug FTIR analysis, which was successfully applied to identify samples in other similar cases.展开更多
文摘The electrodeposition of antimony in alkaline solutions containing xylitol was investigated using cyclic voltammetry,linear sweep voltammetry and chronoamperometry.The antimony electrodeposition and the chemical stability of xylitol in alkaline solutions were studied by cyclic voltammetric technique.Apparent activation energy,apparent transfer coefficient and exchange current density were obtained by linear sweep voltammetric technique.Initial stages of antimony electrocrystallization were determined by chronoamperometry.Xylitol in alkaline solutions exhibits high chemical stability and there is no redox in solutions when the potential ranges from-1.20 V to ＋0.60 V（vs Hg/HgO）.There is no other redox reaction but hydrolysis occurring on stainless steel in the potential range of-1.75 V to 1.25 V（vs Hg/HgO） while the xylitol decomposition maybe take place on antimony electrode when potential is more negative than-1.70 V（vs Hg/HgO）.Cyclic voltammograms with different scan rates indicate that the antimony electrodeposition process is an electrocrystallization which is a completely irreversible electrode process.The apparent activation energy,apparent transfer coefficient and exchange current density were calculated to be 46.33 kJ/mol,0.64 and 4.40×10-6 A/m2,respectively.The analyses of the chronoamperometric responses support the view of a three-dimensional growth under progressive nucleation.The average diffusion coefficient of antimony was calculated to be 1.53×10-6 cm2/s.
基金Project(20976058)supported by the National Natural Science Foundation of China
文摘Growth and crystallization of titanium anodized films were studied by performing the anodization of the sputter-deposited titanium samples under cyclic voltammetry （CV） mode at very low potentials. The surface features, crystalline behaviors and chemical compositions of the formed anodic oxide layers were detected by AFM, SE and XPS. It was found that the structure of the titanium anodized films is crystalline, even though the maximum oxidation potential （（Pmax） is very low （as low as 1000 mY）. Both enlarging the applied voltage and reducing the potential scanning rate are beneficial for the growth and crystallization of titanium oxide films. It was thought that the internal compressive stress, other than the local joule heating accepted for many researchers, is the main force of stimulating the crystallization of anodic titanium oxide films at very low potentials.
文摘Antofloxacin free base is prepared from antofloxacin hydrochloride by removing hydrogen chloride. Its crystal is obtained by slow evaporation of an acetonitrile-methanol mixed solution. Single-crystal X-ray diffraction reveals that the crystallography belongs to a triclinic PI space group with cell parameters： a = 0. 663 07（13） nm, b = 0. 898 39（18） nm, c = 1. 569 0（3） nm, α = 75.12（3）°,β = 87.92（3）°, γ = 77.57 （3）°. Antofloxacin shows no fluorescence in solution, but the crystalline state emits strong green light at 510 nm under the excitation of 360 nm, indicating a fluorescence enhancement induced by aggregation. It demonstrates that intermolecular packing and interaction in the crystal lead to the improved fluorescence quantum yield. These results provide important intbrmation for the further exploration of the structure-activity relationship of antofloxacin and the development of new drugs.
文摘The analysis of solar cell performance has been done by simulating the external I-V characteristics of n +/p/p + single crystal silicon solar cell under high light intensity and 1.5 air mass (AM). This method allows the maximization of solar cell efficiency. To fabricate low-cost n +/p/p + single crystal silicon solar cells, solid source of doped phosphorous and boron was used.
基金National Technology Support Project Foundation China (Grant No. 2011BAK04B03)
文摘N,N-Dimethylamphetamine （DMA） is a methamphetamine （MA） analog and considered as an amphetamine-derived designer drug. In this study, a method of gas chromatography-mass spectrometry （GC-MS） combined with nuclear magnetic resonance spectroscopy （1H and 13C NMR） was developed for the identification of dimethylamphetamine in a suspect exhibit. The results showed that purity of this sample was above 99% by GC-MS area normalization. Therefore, it could be used as a dimethylamphetamine reference substance in drug FTIR analysis, which was successfully applied to identify samples in other similar cases.
