A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts of titanium(IV),based upon the catalytic effect of Ti(IV) on the oxidation of acid chrome blue K (ACBK) by hydrogen perox...A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts of titanium(IV),based upon the catalytic effect of Ti(IV) on the oxidation of acid chrome blue K (ACBK) by hydrogen peroxide in 0.002 mol/L sulfuric acid,is described. The reaction rate is monitored spectrophotometrically by measuring the decrease in absorbance of ACBK at 524 nm. The detection limit of the method is 1.01×10?9 g/mL,and the linear range is 0-0.048 mg/L. The influence of acidity,concentration of reactants,reaction time,reaction temperature and for-eign ions is also discussed. The optimum reaction conditions were established and some kinetic parameters determined. The apparent activation energy of the catalytic reaction is 5.32 kJ/mol. The relative standard deviation for the determi-nation of titanium(IV) at the concentration of 0.048 mg/L is calculated to be 1.31% (n = 11). In combination with sol-vent extraction separation,the method has been successfully applied to the determination of trace titanium(IV) in human hair,plant matter,tea and rock samples. The results are in good agreement with the certified values with the relative standard deviations (RSD) of 1.4%-3.5%.展开更多
In China, the technical information currently available both domestically and abroad has been reviewed in an attempt to integrate the technique of ultraviolet air disinfection with Grade Ⅱ filters and develop a steri...In China, the technical information currently available both domestically and abroad has been reviewed in an attempt to integrate the technique of ultraviolet air disinfection with Grade Ⅱ filters and develop a sterile conservation-oriented environment. As detection showed, such a sanitary system of air disinfection, integrated by ultraviolet air disinfection and Grade Ⅱ filters can reach the same standard of cleanliness as a high efficiency particle filter. This system easily satisfies the cleaning of air in hospital wards, surpassing the sterile air standards and the requirements of the National Bacteria Indicator （NBI）. As a result of this system＇s efficiency, resources and running costs can be reduced dramatically. Therefore, revision of the national standards of Structural Technical Specification of the Cleaning Operation Department needs to move forward.展开更多
We present a novel electrochemical technique for the fabrication of nano-photonic crystal structures. Based on a specially designed electrolyte, porous silicon(PSi) layers with different porosities are possible to be ...We present a novel electrochemical technique for the fabrication of nano-photonic crystal structures. Based on a specially designed electrolyte, porous silicon(PSi) layers with different porosities are possible to be produced on highly-doped n-type silicon substrate by varying the applied current density which determines the size and the morphology of pores. By applying an alternative current density modulation during anodization, porous silicon photonic crystals are obtained using HF-containing electrolyte without oxidizing components. The current burst model(CBM) is employed to interpret the mechanism of the formation of the macropore porous silicon.展开更多
基金Project 0520002 supported by the Natural Science Foundation of Jiangxi Province
文摘A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts of titanium(IV),based upon the catalytic effect of Ti(IV) on the oxidation of acid chrome blue K (ACBK) by hydrogen peroxide in 0.002 mol/L sulfuric acid,is described. The reaction rate is monitored spectrophotometrically by measuring the decrease in absorbance of ACBK at 524 nm. The detection limit of the method is 1.01×10?9 g/mL,and the linear range is 0-0.048 mg/L. The influence of acidity,concentration of reactants,reaction time,reaction temperature and for-eign ions is also discussed. The optimum reaction conditions were established and some kinetic parameters determined. The apparent activation energy of the catalytic reaction is 5.32 kJ/mol. The relative standard deviation for the determi-nation of titanium(IV) at the concentration of 0.048 mg/L is calculated to be 1.31% (n = 11). In combination with sol-vent extraction separation,the method has been successfully applied to the determination of trace titanium(IV) in human hair,plant matter,tea and rock samples. The results are in good agreement with the certified values with the relative standard deviations (RSD) of 1.4%-3.5%.
文摘In China, the technical information currently available both domestically and abroad has been reviewed in an attempt to integrate the technique of ultraviolet air disinfection with Grade Ⅱ filters and develop a sterile conservation-oriented environment. As detection showed, such a sanitary system of air disinfection, integrated by ultraviolet air disinfection and Grade Ⅱ filters can reach the same standard of cleanliness as a high efficiency particle filter. This system easily satisfies the cleaning of air in hospital wards, surpassing the sterile air standards and the requirements of the National Bacteria Indicator （NBI）. As a result of this system＇s efficiency, resources and running costs can be reduced dramatically. Therefore, revision of the national standards of Structural Technical Specification of the Cleaning Operation Department needs to move forward.
基金supported by the National Natural Science Foundation of China(No.61265009)the Excellent Youth Foundation of Shihezi University(No.2012ZRKXYQ-YD20)the Doctoral Research Foundation of Shihezi University(No.RCZX201327)
文摘We present a novel electrochemical technique for the fabrication of nano-photonic crystal structures. Based on a specially designed electrolyte, porous silicon(PSi) layers with different porosities are possible to be produced on highly-doped n-type silicon substrate by varying the applied current density which determines the size and the morphology of pores. By applying an alternative current density modulation during anodization, porous silicon photonic crystals are obtained using HF-containing electrolyte without oxidizing components. The current burst model(CBM) is employed to interpret the mechanism of the formation of the macropore porous silicon.
