Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food produ...Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food production, Sudan Dyes are banned to be used as food dyes in our country.展开更多
A simple isocratic HPLC technique has been developed for the quantitative analysis of phenolic acids (PAs) in fruits and vegetables. Nine benzoic and cinnamic acid derivatives were separated in less than 30 min, and t...A simple isocratic HPLC technique has been developed for the quantitative analysis of phenolic acids (PAs) in fruits and vegetables. Nine benzoic and cinnamic acid derivatives were separated in less than 30 min, and the resolution was all more than 1.23. The ranges of linearity for PAs standards were 0.2-100 ng, even up to 600 ng (r = 0.983-1.000) and the detection limits were 0.02-0.24 mg/kg. Samples of fresh vegetables and fruits were extracted with 80% mcthanol and ethyl acetate, then purified with C18 Sep-Pak cartridge and determined by HPLC. This method was applied to the determination of PAs in 7 kinds of fruits and vegetables, i.e., apple, pear, Chinese cabbage, cauliflower, turnip, soybean sprout and white grape wine. The content of the 9 PAs varied widely in the 7 kinds ol'foods studied. The average concentrations ofchlorogenic acid in apple (100.2 mg/kg) and pear (30.8 mg/kg) were quite high, and sinapinic acid was remarkable (42.5 mg/kg) in Chinese cabbage, and protocatechuic acid had the highest concentration of all the PAs in white wine.展开更多
A new rapid method for the analysis of chromate ion in water by using high performance capillary electrophoresis is described. The detection limit is 1.0 mu g/ml by using 100 m mol/l Tris-HCl buffer containing 2 m mol...A new rapid method for the analysis of chromate ion in water by using high performance capillary electrophoresis is described. The detection limit is 1.0 mu g/ml by using 100 m mol/l Tris-HCl buffer containing 2 m mol/l 1,6-hexanediamine which was used as an electroosmosis modifier to improve the separation and detection sensitivity.展开更多
A low noise oscillator is a crucial component in determining system performance in modern communication,microwave spectroscopy,microwave-based sensing(including radar and remote sensing),and metrology systems.In recen...A low noise oscillator is a crucial component in determining system performance in modern communication,microwave spectroscopy,microwave-based sensing(including radar and remote sensing),and metrology systems.In recent years,ultra-low phase noise photonic microwave oscillators based on optical frequency division have become a paradigm shift for the generation of high performance microwave signals.In this work,we report on-chip low phase noise photonic microwave generation based on spiral resonator referenced lasers and an integrated electro-optical frequency comb.Dual lasers are co-locked to an ultra-high-Q silicon nitride spiral resonator and their relative phase noise is measured below the cavity thermal noise limit,resulting in record low onchip optical phase noise.A broadband integrated electro-optic frequency comb is utilized to divide down the relative phase noise of the spiral resonator referenced lasers to the microwave domain,resulting in recordlow phase noise for chip-based oscillators(-69 d Bc∕Hz at 10 Hz offset,and-144 d Bc∕Hz at 10 k Hz offset for a 10 GHz carrier scaled from 37.3 GHz output).The exceptional phase noise performance,planar chip design,high technology readiness level,and foundry-ready processing of the current work represent a major advance of integrated photonic microwave oscillators.展开更多
文摘Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food production, Sudan Dyes are banned to be used as food dyes in our country.
文摘A simple isocratic HPLC technique has been developed for the quantitative analysis of phenolic acids (PAs) in fruits and vegetables. Nine benzoic and cinnamic acid derivatives were separated in less than 30 min, and the resolution was all more than 1.23. The ranges of linearity for PAs standards were 0.2-100 ng, even up to 600 ng (r = 0.983-1.000) and the detection limits were 0.02-0.24 mg/kg. Samples of fresh vegetables and fruits were extracted with 80% mcthanol and ethyl acetate, then purified with C18 Sep-Pak cartridge and determined by HPLC. This method was applied to the determination of PAs in 7 kinds of fruits and vegetables, i.e., apple, pear, Chinese cabbage, cauliflower, turnip, soybean sprout and white grape wine. The content of the 9 PAs varied widely in the 7 kinds ol'foods studied. The average concentrations ofchlorogenic acid in apple (100.2 mg/kg) and pear (30.8 mg/kg) were quite high, and sinapinic acid was remarkable (42.5 mg/kg) in Chinese cabbage, and protocatechuic acid had the highest concentration of all the PAs in white wine.
文摘A new rapid method for the analysis of chromate ion in water by using high performance capillary electrophoresis is described. The detection limit is 1.0 mu g/ml by using 100 m mol/l Tris-HCl buffer containing 2 m mol/l 1,6-hexanediamine which was used as an electroosmosis modifier to improve the separation and detection sensitivity.
基金Defense Advanced Research Projects Agency(HR001122C0019)。
文摘A low noise oscillator is a crucial component in determining system performance in modern communication,microwave spectroscopy,microwave-based sensing(including radar and remote sensing),and metrology systems.In recent years,ultra-low phase noise photonic microwave oscillators based on optical frequency division have become a paradigm shift for the generation of high performance microwave signals.In this work,we report on-chip low phase noise photonic microwave generation based on spiral resonator referenced lasers and an integrated electro-optical frequency comb.Dual lasers are co-locked to an ultra-high-Q silicon nitride spiral resonator and their relative phase noise is measured below the cavity thermal noise limit,resulting in record low onchip optical phase noise.A broadband integrated electro-optic frequency comb is utilized to divide down the relative phase noise of the spiral resonator referenced lasers to the microwave domain,resulting in recordlow phase noise for chip-based oscillators(-69 d Bc∕Hz at 10 Hz offset,and-144 d Bc∕Hz at 10 k Hz offset for a 10 GHz carrier scaled from 37.3 GHz output).The exceptional phase noise performance,planar chip design,high technology readiness level,and foundry-ready processing of the current work represent a major advance of integrated photonic microwave oscillators.
