[Objective] This study aimed to analyze the volatile constituents in bamboo leaves. [Method] The volatile compositions in bamboo leaves were analyzed by headspace-gas chromatography-mass spectrometry （HS-GC/MS）, and...[Objective] This study aimed to analyze the volatile constituents in bamboo leaves. [Method] The volatile compositions in bamboo leaves were analyzed by headspace-gas chromatography-mass spectrometry （HS-GC/MS）, and identified by searching their mass spectra in NIST database. The relative percentages of them were calculated by the GC peak areas. [Result] Fifty-three chemical constituents in bamboo leaves were separated. Among them, the main components were alcohols, ketones and aldehydes, and these compounds contained unsaturated bonds. [Con- clusion] HS-GC/MS was simple and less sample-demanding and can be used for rapid analysis of volatile constituents in bamboo leaves and provide scientific basis for further research and development of bamboo leaves.展开更多
This paper investigated the feasibility of sonication as an advanced treatment method for drinking water production and used comprehensive indexes of water quality to examine its efficiency. Results show that sonicati...This paper investigated the feasibility of sonication as an advanced treatment method for drinking water production and used comprehensive indexes of water quality to examine its efficiency. Results show that sonication significantly reduces the toxicity of water. Sonication with 5 W/L at 90 kHz lasting for 30 rain decreases the water SUVA and the disinfection byproduct formation potential （DBPFP） by 38.7% and 27. 2% respectively. Sonication also decreases the UV254 by more than 50% through destroying unsaturated chemical bonds. Higher sound intensity and higher frequency benefit the reduction of TOC and UV254. Besides, sonication significantly increases the affinity of organics with granular activated carbon （ GAC ） , and thus the hybrid sonication-GAC method reduces the water TOC, COD, UV254, and DBPFP by 78.3%, 69.4%, 75.7%, and 70.0% respectively. Therefore, sonication and the hybrid sonication-GAC metbod are proposed as advanced treatment methods for drinking water.展开更多
Oils of AD （Adansonia digitata）, AL （Albizia lebbeck） and DO （Daniellia oliveri） were studied using ^13C NMR （nuclear magnetic resonance） and ^1H NMR. The gated decoupled high resolution ^13C NMR spectra revea...Oils of AD （Adansonia digitata）, AL （Albizia lebbeck） and DO （Daniellia oliveri） were studied using ^13C NMR （nuclear magnetic resonance） and ^1H NMR. The gated decoupled high resolution ^13C NMR spectra revealed the presence of both saturated and unsaturated triacylglycerides. However, there is a higher percentage of unsaturation in AL seed oil. The peaks at 0.7 ppm to 0.9 ppm which correspond to the terminal methyl groups in the fatty acid and that at 1.2 ppm to 1.3 ppm are more intense and bigger in DO which show that it is more saturated than AD and AL oils. The results obtained by ^13C NMR and ^1H NMR are compared favorably with those obtained by gas chromatographic analysis.展开更多
A manganese-catalyzed bicyclic annulation of imines with α,β-unsaturated esters via C–H activation is described, which provides an expedient access to fused β-lactams in one-step operation with high efficiency and...A manganese-catalyzed bicyclic annulation of imines with α,β-unsaturated esters via C–H activation is described, which provides an expedient access to fused β-lactams in one-step operation with high efficiency and good functional group tolerance. Of note, both ketimines and aldimines are amenable to this transformation. Mechanistic studies have identified a five-membered azamanganacycle as the key reaction intermediate.展开更多
基金Supported by National Natural Science Foundation of China(31171787)College Student Innovation Fund of Hefei University of Technology(2012CXCY395)~~
文摘[Objective] This study aimed to analyze the volatile constituents in bamboo leaves. [Method] The volatile compositions in bamboo leaves were analyzed by headspace-gas chromatography-mass spectrometry （HS-GC/MS）, and identified by searching their mass spectra in NIST database. The relative percentages of them were calculated by the GC peak areas. [Result] Fifty-three chemical constituents in bamboo leaves were separated. Among them, the main components were alcohols, ketones and aldehydes, and these compounds contained unsaturated bonds. [Con- clusion] HS-GC/MS was simple and less sample-demanding and can be used for rapid analysis of volatile constituents in bamboo leaves and provide scientific basis for further research and development of bamboo leaves.
基金Sponsored by the National High Technology Research and Development Program of China(Grant No.2007AA06Z339)the National Science Foundation for Post-doctoral Scientists of China(Grant No.2006AA06Z306)
文摘This paper investigated the feasibility of sonication as an advanced treatment method for drinking water production and used comprehensive indexes of water quality to examine its efficiency. Results show that sonication significantly reduces the toxicity of water. Sonication with 5 W/L at 90 kHz lasting for 30 rain decreases the water SUVA and the disinfection byproduct formation potential （DBPFP） by 38.7% and 27. 2% respectively. Sonication also decreases the UV254 by more than 50% through destroying unsaturated chemical bonds. Higher sound intensity and higher frequency benefit the reduction of TOC and UV254. Besides, sonication significantly increases the affinity of organics with granular activated carbon （ GAC ） , and thus the hybrid sonication-GAC method reduces the water TOC, COD, UV254, and DBPFP by 78.3%, 69.4%, 75.7%, and 70.0% respectively. Therefore, sonication and the hybrid sonication-GAC metbod are proposed as advanced treatment methods for drinking water.
文摘Oils of AD （Adansonia digitata）, AL （Albizia lebbeck） and DO （Daniellia oliveri） were studied using ^13C NMR （nuclear magnetic resonance） and ^1H NMR. The gated decoupled high resolution ^13C NMR spectra revealed the presence of both saturated and unsaturated triacylglycerides. However, there is a higher percentage of unsaturation in AL seed oil. The peaks at 0.7 ppm to 0.9 ppm which correspond to the terminal methyl groups in the fatty acid and that at 1.2 ppm to 1.3 ppm are more intense and bigger in DO which show that it is more saturated than AD and AL oils. The results obtained by ^13C NMR and ^1H NMR are compared favorably with those obtained by gas chromatographic analysis.
基金supported by the National Basic Research Program of China (2012CB821600)the National Natural Science Foundation of China (21322203, 21272238, 21521002)
文摘A manganese-catalyzed bicyclic annulation of imines with α,β-unsaturated esters via C–H activation is described, which provides an expedient access to fused β-lactams in one-step operation with high efficiency and good functional group tolerance. Of note, both ketimines and aldimines are amenable to this transformation. Mechanistic studies have identified a five-membered azamanganacycle as the key reaction intermediate.
