ZnS nanobelts with large aspect ratio are successfully synthesized on a large scale through thermally evaporating of ZnS powder with a trace of SnO_2 powder using gold coated Si wafer as the substrate at 1100°C.T...ZnS nanobelts with large aspect ratio are successfully synthesized on a large scale through thermally evaporating of ZnS powder with a trace of SnO_2 powder using gold coated Si wafer as the substrate at 1100°C.The results indicate that the as-obtained ZnS nanobelts are about 10 nm in thickness and hundreds of micrometers in length,and the aspect ratio reaches more than 104.Substrate dependent experiments are conducted to better study the growth mechanism of the ZnS nanobelts.Subsequently,optical properties of the as-synthesized ZnS nanobelts are also investigated by using a cathodoluminescence(CL) system,which shows the existence of a strong ultraviolet emission at 342 nm and two poor emission peaks at 522 nm and 683 nm at room temperature,respectively.展开更多
ZnS nanophases were synthesized through a low-temperature route using a mixed solvent, diethylenetriamine （DETA） and deionized water （DIW）, as the reaction medium. The assynthesized products were characterized by ...ZnS nanophases were synthesized through a low-temperature route using a mixed solvent, diethylenetriamine （DETA） and deionized water （DIW）, as the reaction medium. The assynthesized products were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and high-resolution transmission electron microscopy （HRTEM）. The experimental results indicate that ZnS nanophase is formed through a phase evolution of ZnS·（DETA）1/2→ ZnS.DETA→ZnS. The ZnS flower-like microspheres sized around 2μm consist of many nanobelts whose structure could be regarded as an alternative admixture of hexagonal wurtzite （WZ） and cubic zinc blende （ZB）. The optical absorption measurements demonstrate that the spectral feature of the sample changes with the evolution of the phase structure.展开更多
A large number of ZnS nanosaws are synthesized on Si substrates in the presence of Au catalyst by thermally evaporating ZnS powder. Morphologies and structures of thus-grown ZnS nanosaws are characterized by a field e...A large number of ZnS nanosaws are synthesized on Si substrates in the presence of Au catalyst by thermally evaporating ZnS powder. Morphologies and structures of thus-grown ZnS nanosaws are characterized by a field emission scanning electron microscopy （FE-SEM） and a transmission electron microscopy （TEM）. The results show that temperature of the Si substrates used for collection of the products is a critical experimental parameter for the formation of ZnS nanostruetures with different morphologies. The growth mechanism of the ZnS nanosaws is discussed on the basis of the experimental findings.展开更多
When a protein is encapsulated into poly( DL -lactide-co-glycolide)(PLGA) microspheres by means of the double-emulsion method,the harsh microspheres formation process including ultrasonification,exposure to an organic...When a protein is encapsulated into poly( DL -lactide-co-glycolide)(PLGA) microspheres by means of the double-emulsion method,the harsh microspheres formation process including ultrasonification,exposure to an organic solvent and a polymer may cause the denaturation of the protein. In this study,we investigated the enzymatic activity change and the effect of the excipients on the stability of recombinant human Cu,Zn-superoxide dismutase(rhCu,Zn-SOD) during the emulsification. The specific activity recovery was found to be concentration dependent and the excipients involved such as PEG 600 and Tween 20,and trehalose were shown to increase the stability of rhCu,Zn-SOD. The protein structural integrity within the microspheres was analyzed by FTIR. The structure of rhCu,Zn-SOD within PLGA microspheres containing trehalose was found to be similar to that of the native solid state,whereas the protein encapsulated during the preparation in the absence of any excipient changed due to the possible hydrophobic interaction with the polymer. The results suggest that a rational stability strategy for protein to be encapsulated into microspheres should aim at different processes.展开更多
基金sponsored by the Scientific Research Fund of Heilongjiang Provincial Education Department(11551117)China Postdoctoral Foundation(20090460875)+1 种基金Pre-research Fund(2009KYG-01)Youth Skeleton Teacher Fund(10KXQ-07)of Harbin Normal University
文摘ZnS nanobelts with large aspect ratio are successfully synthesized on a large scale through thermally evaporating of ZnS powder with a trace of SnO_2 powder using gold coated Si wafer as the substrate at 1100°C.The results indicate that the as-obtained ZnS nanobelts are about 10 nm in thickness and hundreds of micrometers in length,and the aspect ratio reaches more than 104.Substrate dependent experiments are conducted to better study the growth mechanism of the ZnS nanobelts.Subsequently,optical properties of the as-synthesized ZnS nanobelts are also investigated by using a cathodoluminescence(CL) system,which shows the existence of a strong ultraviolet emission at 342 nm and two poor emission peaks at 522 nm and 683 nm at room temperature,respectively.
基金Supported by the project of Nano-molecular Functional Materials of Fujian Province (2005HZ01-1)
文摘ZnS nanophases were synthesized through a low-temperature route using a mixed solvent, diethylenetriamine （DETA） and deionized water （DIW）, as the reaction medium. The assynthesized products were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and high-resolution transmission electron microscopy （HRTEM）. The experimental results indicate that ZnS nanophase is formed through a phase evolution of ZnS·（DETA）1/2→ ZnS.DETA→ZnS. The ZnS flower-like microspheres sized around 2μm consist of many nanobelts whose structure could be regarded as an alternative admixture of hexagonal wurtzite （WZ） and cubic zinc blende （ZB）. The optical absorption measurements demonstrate that the spectral feature of the sample changes with the evolution of the phase structure.
基金Supported by the National Natural Science Foundation of China under Grant No 50772024, the Opening Research Foundation of National Centre for Nanoscience and Technology （NCNST） of China, and the National Basic Research Programme of China under Grant No 2003CB716900.
文摘A large number of ZnS nanosaws are synthesized on Si substrates in the presence of Au catalyst by thermally evaporating ZnS powder. Morphologies and structures of thus-grown ZnS nanosaws are characterized by a field emission scanning electron microscopy （FE-SEM） and a transmission electron microscopy （TEM）. The results show that temperature of the Si substrates used for collection of the products is a critical experimental parameter for the formation of ZnS nanostruetures with different morphologies. The growth mechanism of the ZnS nanosaws is discussed on the basis of the experimental findings.
文摘When a protein is encapsulated into poly( DL -lactide-co-glycolide)(PLGA) microspheres by means of the double-emulsion method,the harsh microspheres formation process including ultrasonification,exposure to an organic solvent and a polymer may cause the denaturation of the protein. In this study,we investigated the enzymatic activity change and the effect of the excipients on the stability of recombinant human Cu,Zn-superoxide dismutase(rhCu,Zn-SOD) during the emulsification. The specific activity recovery was found to be concentration dependent and the excipients involved such as PEG 600 and Tween 20,and trehalose were shown to increase the stability of rhCu,Zn-SOD. The protein structural integrity within the microspheres was analyzed by FTIR. The structure of rhCu,Zn-SOD within PLGA microspheres containing trehalose was found to be similar to that of the native solid state,whereas the protein encapsulated during the preparation in the absence of any excipient changed due to the possible hydrophobic interaction with the polymer. The results suggest that a rational stability strategy for protein to be encapsulated into microspheres should aim at different processes.
