A simple and efficient procedure has been developed for the synthesis of organostannane compounds by one-pot reaction of stannane halides, magnesium turnings and organic halides in the presence of 1, 2-dibromoethane u...A simple and efficient procedure has been developed for the synthesis of organostannane compounds by one-pot reaction of stannane halides, magnesium turnings and organic halides in the presence of 1, 2-dibromoethane under ultrasound irradiation for the first time.展开更多
Ag nanoparitcles were prepared via Ultrasound-assisted Membrane Reaction(UAMR)method.The key issue of the method is to control precisely the injection speed of the reactants by pulseless pump to make the nanoparticles...Ag nanoparitcles were prepared via Ultrasound-assisted Membrane Reaction(UAMR)method.The key issue of the method is to control precisely the injection speed of the reactants by pulseless pump to make the nanoparticles of Ag with small size and narrow size distribution.The size and morphology of silver nanoparticles were characterized with Transmission Electron Microscope(TEM)and UV-Vis spectrum.The experiment results show that the size of Ag nanoparticles prepared via UAMR method was smaller than that via Ultrasound-assisted Dropping Reaction(UADR)method.The size of 80% Ag nanoparticles prepared via UAMR was ranged from 3 nm to 5 nm with the mean particle size 4.7 nm and considerable narrow size distribution.The Ag hydrosol fabricated via UAMR method was very stable at room temperature,even within three months.展开更多
为研究超声对花色苷稳定性影响规律及其降解动力学,采用单因素试验在超声提取模拟体系中研究4种因素(功率密度、温度、溶剂、p H值)对5种常见花色苷稳定性的影响规律,采用试错法分析花色苷超声降解动力学,并结合液相色谱-质谱联用技术...为研究超声对花色苷稳定性影响规律及其降解动力学,采用单因素试验在超声提取模拟体系中研究4种因素(功率密度、温度、溶剂、p H值)对5种常见花色苷稳定性的影响规律,采用试错法分析花色苷超声降解动力学,并结合液相色谱-质谱联用技术分析超声处理后的降解产物。结果表明:随着温度的升高,花色苷在超声处理下的降解率下降;5种花色苷在体积分数70%乙醇溶液中降解最少;p H 1~5范围内,花色苷降解率呈先增加后减少趋势。飞燕草素-3-葡萄糖苷的超声降解符合一级动力学模型,矢车菊素-3-葡萄糖苷、天竺葵素-3-葡萄糖苷、锦葵素-3-葡萄糖苷、芍药素-3-葡萄糖苷的超声降解符合零级动力学模型。在天竺葵素-3-葡萄糖苷、锦葵素-3-葡萄糖苷、芍药素-3-葡萄糖苷、矢车菊素-3-葡萄糖苷的降解产物中都检测到8-β-D-吡喃葡萄糖基-2,4-二羟基-6-氧代环己基-2,4-二烯基乙酸,同时也检测到山柰酚、槲皮素、丁香酸、阿魏酸、2,6-二甲氧基苯酚等。展开更多
基金This work was financial supported by the National Natural Science Foundation of China (Grant No. 20072012) and the Special Research Grant for Doctoral Sites in Chinese Universities (Grant No. 20010730001).
文摘A simple and efficient procedure has been developed for the synthesis of organostannane compounds by one-pot reaction of stannane halides, magnesium turnings and organic halides in the presence of 1, 2-dibromoethane under ultrasound irradiation for the first time.
文摘Ag nanoparitcles were prepared via Ultrasound-assisted Membrane Reaction(UAMR)method.The key issue of the method is to control precisely the injection speed of the reactants by pulseless pump to make the nanoparticles of Ag with small size and narrow size distribution.The size and morphology of silver nanoparticles were characterized with Transmission Electron Microscope(TEM)and UV-Vis spectrum.The experiment results show that the size of Ag nanoparticles prepared via UAMR method was smaller than that via Ultrasound-assisted Dropping Reaction(UADR)method.The size of 80% Ag nanoparticles prepared via UAMR was ranged from 3 nm to 5 nm with the mean particle size 4.7 nm and considerable narrow size distribution.The Ag hydrosol fabricated via UAMR method was very stable at room temperature,even within three months.
文摘为研究超声对花色苷稳定性影响规律及其降解动力学,采用单因素试验在超声提取模拟体系中研究4种因素(功率密度、温度、溶剂、p H值)对5种常见花色苷稳定性的影响规律,采用试错法分析花色苷超声降解动力学,并结合液相色谱-质谱联用技术分析超声处理后的降解产物。结果表明:随着温度的升高,花色苷在超声处理下的降解率下降;5种花色苷在体积分数70%乙醇溶液中降解最少;p H 1~5范围内,花色苷降解率呈先增加后减少趋势。飞燕草素-3-葡萄糖苷的超声降解符合一级动力学模型,矢车菊素-3-葡萄糖苷、天竺葵素-3-葡萄糖苷、锦葵素-3-葡萄糖苷、芍药素-3-葡萄糖苷的超声降解符合零级动力学模型。在天竺葵素-3-葡萄糖苷、锦葵素-3-葡萄糖苷、芍药素-3-葡萄糖苷、矢车菊素-3-葡萄糖苷的降解产物中都检测到8-β-D-吡喃葡萄糖基-2,4-二羟基-6-氧代环己基-2,4-二烯基乙酸,同时也检测到山柰酚、槲皮素、丁香酸、阿魏酸、2,6-二甲氧基苯酚等。
