Essential oil was extracted from Artemisia lavandulaefolia DC.by steam distillation（SD） and supercritical-CO2 fluid extraction（SFE）,respectively.The constituents of the essentil oils extracted with those two metho...Essential oil was extracted from Artemisia lavandulaefolia DC.by steam distillation（SD） and supercritical-CO2 fluid extraction（SFE）,respectively.The constituents of the essentil oils extracted with those two methods were analyzed by gas chromatography-mass spectrometry（GC-MS） and insecticidal activities of the essential oils were evaluated,then the results were compared to assess their biological activity.Thirty-one compounds were identified in the essential oil extracted by SD,and its main components were eucalyptol,α,α,4-trimethyl-3-cyclohexene-1-methanol and so on.Twenty-two compounds were identified for the essential oil extracted by SFE,and its main components were cyclodecene,n-hexadecanoic acid and so on.Six chemical compositions were all contained in the essential oils extracted by the two methods,i.e.,eucalyptol,α,α,4-trimethyl-3-cyclohexene-1-methanol,caryophyllene,[3aS-（3aα,3bβ,4β,7α,7aS）]-octahydro-7-methyl-3-methylene-4-（1-methylethyl）-1H-cyclopenta[1,3]cyclopropa-[1,2]benzene,nerolidol and（-）-Spathulenol.The fumigation toxicity of the essential oil obtained by means of SD to the adults of Sitophilus zeamais is significantly higher than that of the essential oil by means of SFE.The contact toxicity of the essential oil obtained by means of SFE to the adults of S.zeamais is higher than that of the essential oil obtained by means of SD,but the difference is not significant.展开更多
Steam pretreatment was employed to disrupt Microalgal cells for lipids extraction.Effects of steam pretreatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM)and tran...Steam pretreatment was employed to disrupt Microalgal cells for lipids extraction.Effects of steam pretreatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Effect of treatment on lipid extraction was also studied.Microalgal cell walls were distorted after steam pretreatment due to the hydrolysis of organic macromolecules contained in cell wall.Maximum curvature was increased from 1.88×10^(-6) m^(-1) to 1.43×10^(-7) m^(-1) after treatment with the steam at 130℃.The fractal dimension of microalgal cells increased from 1.25 to 1.30 after pretreatment for 15 min,and further increased to 1.47 when the pretreatment time was increased to 60 min.Increased steam pretreatment temperature and time enhanced the hydrolysis of organic macromolecules,and finally destroyed microalgal cell walls at pretreatment temperature of 130℃and pretreatment time of 60 min.Lipid extracted from wet microalgal was significantly increased(2.1-fold)after pretreatment.展开更多
Theory and concepts of boundary layer mass transfer is applied to correlate experimental data on extraction of essential oils from vegetable leaves and stems, using steam. From these theory, concepts and experimental ...Theory and concepts of boundary layer mass transfer is applied to correlate experimental data on extraction of essential oils from vegetable leaves and stems, using steam. From these theory, concepts and experimental data with seven systems, two correlations are developed to predict the Sherwood number and mass transfer coefficient as function of Reynolds and Schmidt numbers. From these equations, the molar flux, the amount of solute extracted, and the yield of extraction is predicted. A steam of higher temperature normally improves the mass transfer and the yield. A method to estimate the enhancement for temperature increase is proposed. The correlations developed are applied to a case with industrial size that was no part of the data for correlation generation. Theory may be applied for industrial applications.展开更多
Glycerol-assisted instant catapult steam explosion(ICSE)of lignocellulose is an effective pretreatment method for enhancing sugar production compared to glycerol-free ICSE.In this study,glycerol-assisted ICSE of corn ...Glycerol-assisted instant catapult steam explosion(ICSE)of lignocellulose is an effective pretreatment method for enhancing sugar production compared to glycerol-free ICSE.In this study,glycerol-assisted ICSE of corn stover was studied in order to understand the reaction mechanisms and further optimize the process.Results showed that water extraction of corn stover prior to ICSE reduced pseudo-lignin formation.The combination of water extraction and glycerol-assisted ICSE led to the formation of lignin with a lower molecular weight(Mw)of 2851 g/mol than 3521 g/mole of that from the combination of water extraction and glycerol-free ICSE.1H-13C NMR analysis revealed that glycerol likely reacted with lignin carboxylic OHs through esterification while etherification of aliphatic OHs was not observed in ICSE.These lignin analyses indicated that glycerol protected lignin from condensation/repolymerization during glycerol-assisted ICSE.Enzymatic hydrolysis results showed that without water extraction increasing glycerol usage from 0.2 kg/kg stover to 0.4 kg/kg stover improved glucan digestibility to 78%but further increase to 0.5 kg/kg stover reduced glucan digestibility.In addition,at the glycerol usage of 0.2-0.4 kg/kg stover,washing of pretreated stover for removal of glycerol and other biomass-derived compounds did not improve glucan digestibility compared to unwashed ones.Combination of water extraction and glycerol-assisted ICSE led to a high glucan digestibility of 89.7%and a total glucose yield of 25.5 g glucose/100 g stover,which were 30.1%and 7.5 g/100 g stover higher than those derived from glycerol-free ICSE of stover,respectively.Since glycerol is a low-cost carbon source,the resulting enzymatic hydrolysate that contained both glucose and glycerol may be directly used to produce bioproducts by microbial fermentation.展开更多
The physical properties and chemical components of three oil samples extracted from Illicium verum Hook. f. by steam distillation （SD）, solvent extraction （SE） and supercritical fluid extraction （SFE） were compa...The physical properties and chemical components of three oil samples extracted from Illicium verum Hook. f. by steam distillation （SD）, solvent extraction （SE） and supercritical fluid extraction （SFE） were compared with one another and analyzed by Gas Chromatography-Mass Spectrometry （GC-MS）. The quality parameters of star anise essential oil from SFE were close to that of those came from SD and SE. Although the extraction yield of star anise by SFE （9.2 %） was close to the value from SE （9.3%）, it was yet higher than that came from SD （8.2%）. For sensory evaluation, however, three oils were significantly different. The odor and taste of the products from SFE and SE were generally more natural and vivid than that came from distilled oil. The volatile compound revealed that significant differences of the composition existed in the distilled oil and the oleoresins prepared by SFE and SE.展开更多
【Objective】To optimize the steam explosion process condition for extracting polysaccharides from Pseudostellaria heterophylla.【Method】The effects of steam pressure,pressure-maintaining time and material moisture c...【Objective】To optimize the steam explosion process condition for extracting polysaccharides from Pseudostellaria heterophylla.【Method】The effects of steam pressure,pressure-maintaining time and material moisture content on the extraction of polysaccharides from Pseudostellaria heterophylla were studied by response surface methodology based on Box-Behnken design.【Result】The findings showed that each factor could significantly affect the test index,and the optimum condition was as follows:steam pressure 1.50 Mpa,pressuremaintaining time 46 s and material moisture content 46%.Under this condition,the verified experimental value of polysaccharides from Pseudostellaria heterophylla was 39.32%,indicating a relative standard deviation of 2.73%from the predictive value.Meanwhile,scanning electron microcopy(SEM)images showed that the surface physical structure of Pseudostellaria heterophylla was irregularly broken and cracked,which means the physical structure of Pseudostellaria heterophylla was changed and destroyed at the cellular level.【Conclusion】This experiment provides a new approach for the extraction of polysaccharides from Pseudostellaria heterophylla,as well as a reference for the resource utilization of Pseudostellaria heterophylla.展开更多
A comparative study of Cannabis sativa(Hemp)essential constituents obtained by using Supercritical Fluid Extraction(SCFE),Steam Distillation(SD)and Hydrodistillation(HD)is presented here.The optimized extraction tempe...A comparative study of Cannabis sativa(Hemp)essential constituents obtained by using Supercritical Fluid Extraction(SCFE),Steam Distillation(SD)and Hydrodistillation(HD)is presented here.The optimized extraction temperatures were 130,110and 50℃for hydrodistillation,steam distillation and supercritical fluid extraction respectively.The essential oil of C.sativa was analyzed by using Gas chromatography mass spectrometry(GC-MS).A total of 33,30and 31components have been identified in HD,SD and SCFE respectively.Yield of essential oil using SCFE(0.039%)was more than HD(0.025%)and SD(0.035%)extraction respectively.The main component of sesquiterpenes obtained by hydrodistillation at 130℃with their percentages included caryophyllene(40.58%),trans-α-bergamotene(5.41%),humulene(10.97%),cis-β-farnesene(8.53%)and monoterpenes includedα-pinene(2.13%),d-limonene(6.46%),p-cymol(0.65%)and cineole(2.58%)respectively.The main component of sesquiterpenes obtained by SD steam distillation at110℃including caryophyllene(38.60%)trans-α-bergamotene(4.22%),humulene(10.26%),cis-β-farnesene(6.67%)and monoterpenes includedα-pinene(3.21%),d-limonene(7.07%),p-cymol(2.59%)and cineole(3.88%)whereas the more percentages of major components were obtained by SCFE at 50℃included caryophyllene(44.31%),trans-α-bergamotene(6.79%),humulene(11.97%)cis-β-farnesene(9.71%)and monoterpenes includedα-pinene(0.45%),d-limonene(2.13%)p-cymol(0.19%)and cineole(1.38%)respectively.We found yield/efficiency,chemical composition,quality of the essential oils by supercritical fluid extraction superior in terms of modern,green,saving energy and a rapid approach as compared to traditional techniques.展开更多
The technology that waste activated carbon after extracting gold is regenerated with steam under microwave heating was studied. The influence of the activation temperature, activation duration and steam flow rate on i...The technology that waste activated carbon after extracting gold is regenerated with steam under microwave heating was studied. The influence of the activation temperature, activation duration and steam flow rate on iodine adsorption value and regeneration yield of activated carbon was investigated. The response surface methodology （RSM） technique was utilized to optimize the process conditions. The optimum conditions for the preparation of activated carbon are identified to be activation temperature of 831 ℃, activation duration of 40 min and steam flow rate of 2.67 mL/min. The optimum conditions result in an activated carbon with an iodine number of 1048 mg/g and a yield of 40%, and the BET surface area evaluated using nitrogen adsorption isotherm is 1493 m2/g, with total pore volume of 1.242 cm3/g. And the pore structure of activated carbon regenerated is mainly composed of micropores and a small amount of mesopores.展开更多
[Objectives] The aim was to determine the optimum process for the extraction of volatile oil from Alpinia zerumbet fruit.[Methods]Steam distillation was used to extract volatile oil from A. zerumbet fruit. Based on th...[Objectives] The aim was to determine the optimum process for the extraction of volatile oil from Alpinia zerumbet fruit.[Methods]Steam distillation was used to extract volatile oil from A. zerumbet fruit. Based on the single factor tests,an orthogonal test was designed to explore the effects of solid-liquid ratio,soaking time,extraction time and grinding degree of material on the extraction rate. The composition of volatile oil from A. zerumbet fruit was analyzed using gas chromatography-mass spectrometry( GC-MS),and the relative mass fraction of each component was determined by peak area normalization. [Results] With volatile oil yield as the index,the optimum extraction process was determined: solid to liquid ratio of 1∶ 10,soaking time of 0. 5 h,grinding degree of passing through 24-mesh sieve and extraction time of 5 h. A total of 29 compounds were isolated. Among them,the contents of α-terpinene( 24. 894%),1,8-terpadiene( 15. 527%) andα-pinene( 6. 982%) were relatively high. [Conclusions]The optimized extraction process for volatile oil from A. zerumbet fruit is stable and reasonable. Under the optimum extraction process,the extraction effect of volatile oil from A. zerumbet fruit was the best. The chemical components of volatile oil from A. zerumbet fruit were determined by GC-MS as α-terpinene( 24. 894%),1,8-terpadiene( 15. 527%) and α-pinene( 6. 982%).展开更多
Lepidolites are important carriers of Li ores.Because of the strong positive correlation between the presence of Li and F,Li extracted from lepidolite must be defluorinated.Moreover,synergistically extracting Li,Rb,an...Lepidolites are important carriers of Li ores.Because of the strong positive correlation between the presence of Li and F,Li extracted from lepidolite must be defluorinated.Moreover,synergistically extracting Li,Rb,and Cs is important for the comprehensive utilization of lepidolite.Steam roasting converts F to HF without introducing impurities.In this study,the effects of steam roasting on Li activation and the synergistic extraction of Rb and Cs were investigated during the defluorination process.Notably,the defluorination mechanism and migration behavior of F during steam roasting were revealed based on qualitative and quantitative analyses of the liquid and corresponding solid phases.Furthermore,density functional theory calculations were used to investigate the pathways and behaviors of defluorination and the removal behavior of F atoms connected to Al and Li sites,revealing that the F atoms on the(010)crystal surface were easily replaced by water molecules,thereby releasing surface F atoms.Under the optimal roasting conditions,the defluorination efficiency of lepidolite was 91.08%at 880℃for 1 h.Subsequently,the Li encapsulated in the crystal lattice,as well as Rb and Cs,was activated and leached using optimal sulfuric acid leaching.The leaching efficiencies of Li,Rb,and Cs were 97.37%,97.77%,and 97.19%,respectively at 120℃for 2 h.This study provides a comprehensive and systematic perspective on the defluorination and comprehensive utilization of lepidolite,providing a comprehensive,clean,efficient,green,and low-C lepidolite Li extraction process.展开更多
Aroma of Chinese steamed bread（CSB） is one of the important parameters that determines the overall quality attributes and consumer acceptance. However, the aroma profile of CSB still remains poorly understood, mainl...Aroma of Chinese steamed bread（CSB） is one of the important parameters that determines the overall quality attributes and consumer acceptance. However, the aroma profile of CSB still remains poorly understood, mainly because of relying on only a single method for aroma extraction in previous studies. Therefore, the objective of this study was to determine the volatile aroma compounds of five different samples of CSB using three different aroma extraction methods, namely solid-phase microextraction（SPME）, simultaneous distillation–extraction（SDE）, and purge and trap（PT）. All samples showed a unique aroma profile, which could be attributed to their unique microbial consortia.（E）-2-Nonenal and（E,E）-2,4-decadienal were the most prevalent aromatic compounds revealed by SDE, which have not been reported previously, while ethanol and acetic acid proved to be the most dominant compounds by both SPME and PT. Our approach of combining three different aroma extraction methods provided better insights into the aroma profile of CSB, which had remained largely unknown in previous studies.展开更多
Deep learning algorithms show good prospects for remote sensingflood monitoring.They mostly rely on huge amounts of labeled data.However,there is a lack of available labeled data in actual needs.In this paper,we propo...Deep learning algorithms show good prospects for remote sensingflood monitoring.They mostly rely on huge amounts of labeled data.However,there is a lack of available labeled data in actual needs.In this paper,we propose a high-resolution multi-source remote sensing dataset forflood area extraction:GF-FloodNet.GF-FloodNet contains 13388 samples from Gaofen-3(GF-3)and Gaofen-2(GF-2)images.We use a multi-level sample selection and interactive annotation strategy based on active learning to construct it.Compare with otherflood-related datasets,GF-FloodNet not only has a spatial resolution of up to 1.5 m and provides pixel-level labels,but also consists of multi-source remote sensing data.We thoroughly validate and evaluate the dataset using several deep learning models,including quantitative analysis,qualitative analysis,and validation on large-scale remote sensing data in real scenes.Experimental results reveal that GF-FloodNet has significant advantages by multi-source data.It can support different deep learning models for training to extractflood areas.There should be a potential optimal boundary for model training in any deep learning dataset.The boundary seems close to 4824 samples in GF-FloodNet.We provide GF-FloodNet at https://www.kaggle.com/datasets/pengliuair/gf-floodnet and https://pan.baidu.com/s/1vdUCGNAfFwG5UjZ9RLLFMQ?pwd=8v6o.展开更多
基金Supported by the Technology Development Project of Jilin Province,China(Nos.20090571 and 20090262)the Development and Reform Project of Jilin Province,China(No.20071033)+2 种基金the State Administration of Quality Supervision Project,China(No.2008IK253)the Jingyue Development Zone Project of Changchun City,China(No.2007C010)the Scientific Research Fund of Jilin Agricultural University,China(No.2007040)
文摘Essential oil was extracted from Artemisia lavandulaefolia DC.by steam distillation（SD） and supercritical-CO2 fluid extraction（SFE）,respectively.The constituents of the essentil oils extracted with those two methods were analyzed by gas chromatography-mass spectrometry（GC-MS） and insecticidal activities of the essential oils were evaluated,then the results were compared to assess their biological activity.Thirty-one compounds were identified in the essential oil extracted by SD,and its main components were eucalyptol,α,α,4-trimethyl-3-cyclohexene-1-methanol and so on.Twenty-two compounds were identified for the essential oil extracted by SFE,and its main components were cyclodecene,n-hexadecanoic acid and so on.Six chemical compositions were all contained in the essential oils extracted by the two methods,i.e.,eucalyptol,α,α,4-trimethyl-3-cyclohexene-1-methanol,caryophyllene,[3aS-（3aα,3bβ,4β,7α,7aS）]-octahydro-7-methyl-3-methylene-4-（1-methylethyl）-1H-cyclopenta[1,3]cyclopropa-[1,2]benzene,nerolidol and（-）-Spathulenol.The fumigation toxicity of the essential oil obtained by means of SD to the adults of Sitophilus zeamais is significantly higher than that of the essential oil by means of SFE.The contact toxicity of the essential oil obtained by means of SFE to the adults of S.zeamais is higher than that of the essential oil obtained by means of SD,but the difference is not significant.
基金supported by the National Key Research and Development Program-China(2017YFE0122800)Shandong Provincial Natural Science Foundation(ZR2019MC060)+1 种基金Key Research and Development Program of Jining City(2018ZDGH024)a Project of Shandong Province Higher Educational Science and Technology Program(J17KA095)。
文摘Steam pretreatment was employed to disrupt Microalgal cells for lipids extraction.Effects of steam pretreatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Effect of treatment on lipid extraction was also studied.Microalgal cell walls were distorted after steam pretreatment due to the hydrolysis of organic macromolecules contained in cell wall.Maximum curvature was increased from 1.88×10^(-6) m^(-1) to 1.43×10^(-7) m^(-1) after treatment with the steam at 130℃.The fractal dimension of microalgal cells increased from 1.25 to 1.30 after pretreatment for 15 min,and further increased to 1.47 when the pretreatment time was increased to 60 min.Increased steam pretreatment temperature and time enhanced the hydrolysis of organic macromolecules,and finally destroyed microalgal cell walls at pretreatment temperature of 130℃and pretreatment time of 60 min.Lipid extracted from wet microalgal was significantly increased(2.1-fold)after pretreatment.
文摘Theory and concepts of boundary layer mass transfer is applied to correlate experimental data on extraction of essential oils from vegetable leaves and stems, using steam. From these theory, concepts and experimental data with seven systems, two correlations are developed to predict the Sherwood number and mass transfer coefficient as function of Reynolds and Schmidt numbers. From these equations, the molar flux, the amount of solute extracted, and the yield of extraction is predicted. A steam of higher temperature normally improves the mass transfer and the yield. A method to estimate the enhancement for temperature increase is proposed. The correlations developed are applied to a case with industrial size that was no part of the data for correlation generation. Theory may be applied for industrial applications.
基金supported by the Henan Provincial Science and Technology Research Project(222102520015)the Science and Technology Innovation Leading Talents of Central Plains,Henan province,China(204200510018).
文摘Glycerol-assisted instant catapult steam explosion(ICSE)of lignocellulose is an effective pretreatment method for enhancing sugar production compared to glycerol-free ICSE.In this study,glycerol-assisted ICSE of corn stover was studied in order to understand the reaction mechanisms and further optimize the process.Results showed that water extraction of corn stover prior to ICSE reduced pseudo-lignin formation.The combination of water extraction and glycerol-assisted ICSE led to the formation of lignin with a lower molecular weight(Mw)of 2851 g/mol than 3521 g/mole of that from the combination of water extraction and glycerol-free ICSE.1H-13C NMR analysis revealed that glycerol likely reacted with lignin carboxylic OHs through esterification while etherification of aliphatic OHs was not observed in ICSE.These lignin analyses indicated that glycerol protected lignin from condensation/repolymerization during glycerol-assisted ICSE.Enzymatic hydrolysis results showed that without water extraction increasing glycerol usage from 0.2 kg/kg stover to 0.4 kg/kg stover improved glucan digestibility to 78%but further increase to 0.5 kg/kg stover reduced glucan digestibility.In addition,at the glycerol usage of 0.2-0.4 kg/kg stover,washing of pretreated stover for removal of glycerol and other biomass-derived compounds did not improve glucan digestibility compared to unwashed ones.Combination of water extraction and glycerol-assisted ICSE led to a high glucan digestibility of 89.7%and a total glucose yield of 25.5 g glucose/100 g stover,which were 30.1%and 7.5 g/100 g stover higher than those derived from glycerol-free ICSE of stover,respectively.Since glycerol is a low-cost carbon source,the resulting enzymatic hydrolysate that contained both glucose and glycerol may be directly used to produce bioproducts by microbial fermentation.
基金Supported by the Science and Technology Key Project of Guangxi Province (0424008-1C)
文摘The physical properties and chemical components of three oil samples extracted from Illicium verum Hook. f. by steam distillation （SD）, solvent extraction （SE） and supercritical fluid extraction （SFE） were compared with one another and analyzed by Gas Chromatography-Mass Spectrometry （GC-MS）. The quality parameters of star anise essential oil from SFE were close to that of those came from SD and SE. Although the extraction yield of star anise by SFE （9.2 %） was close to the value from SE （9.3%）, it was yet higher than that came from SD （8.2%）. For sensory evaluation, however, three oils were significantly different. The odor and taste of the products from SFE and SE were generally more natural and vivid than that came from distilled oil. The volatile compound revealed that significant differences of the composition existed in the distilled oil and the oleoresins prepared by SFE and SE.
文摘【Objective】To optimize the steam explosion process condition for extracting polysaccharides from Pseudostellaria heterophylla.【Method】The effects of steam pressure,pressure-maintaining time and material moisture content on the extraction of polysaccharides from Pseudostellaria heterophylla were studied by response surface methodology based on Box-Behnken design.【Result】The findings showed that each factor could significantly affect the test index,and the optimum condition was as follows:steam pressure 1.50 Mpa,pressuremaintaining time 46 s and material moisture content 46%.Under this condition,the verified experimental value of polysaccharides from Pseudostellaria heterophylla was 39.32%,indicating a relative standard deviation of 2.73%from the predictive value.Meanwhile,scanning electron microcopy(SEM)images showed that the surface physical structure of Pseudostellaria heterophylla was irregularly broken and cracked,which means the physical structure of Pseudostellaria heterophylla was changed and destroyed at the cellular level.【Conclusion】This experiment provides a new approach for the extraction of polysaccharides from Pseudostellaria heterophylla,as well as a reference for the resource utilization of Pseudostellaria heterophylla.
基金University of Agriculture,Faisalabad for research support
文摘A comparative study of Cannabis sativa(Hemp)essential constituents obtained by using Supercritical Fluid Extraction(SCFE),Steam Distillation(SD)and Hydrodistillation(HD)is presented here.The optimized extraction temperatures were 130,110and 50℃for hydrodistillation,steam distillation and supercritical fluid extraction respectively.The essential oil of C.sativa was analyzed by using Gas chromatography mass spectrometry(GC-MS).A total of 33,30and 31components have been identified in HD,SD and SCFE respectively.Yield of essential oil using SCFE(0.039%)was more than HD(0.025%)and SD(0.035%)extraction respectively.The main component of sesquiterpenes obtained by hydrodistillation at 130℃with their percentages included caryophyllene(40.58%),trans-α-bergamotene(5.41%),humulene(10.97%),cis-β-farnesene(8.53%)and monoterpenes includedα-pinene(2.13%),d-limonene(6.46%),p-cymol(0.65%)and cineole(2.58%)respectively.The main component of sesquiterpenes obtained by SD steam distillation at110℃including caryophyllene(38.60%)trans-α-bergamotene(4.22%),humulene(10.26%),cis-β-farnesene(6.67%)and monoterpenes includedα-pinene(3.21%),d-limonene(7.07%),p-cymol(2.59%)and cineole(3.88%)whereas the more percentages of major components were obtained by SCFE at 50℃included caryophyllene(44.31%),trans-α-bergamotene(6.79%),humulene(11.97%)cis-β-farnesene(9.71%)and monoterpenes includedα-pinene(0.45%),d-limonene(2.13%)p-cymol(0.19%)and cineole(1.38%)respectively.We found yield/efficiency,chemical composition,quality of the essential oils by supercritical fluid extraction superior in terms of modern,green,saving energy and a rapid approach as compared to traditional techniques.
基金Project(2013AA064003)supported by the National High Technology Research and Development Program of ChinaProject(2012HB008)supported by Young and Middle-aged Academic Technology Leader Backup Talent Cultivation Program in Yunnan Province,China
文摘The technology that waste activated carbon after extracting gold is regenerated with steam under microwave heating was studied. The influence of the activation temperature, activation duration and steam flow rate on iodine adsorption value and regeneration yield of activated carbon was investigated. The response surface methodology （RSM） technique was utilized to optimize the process conditions. The optimum conditions for the preparation of activated carbon are identified to be activation temperature of 831 ℃, activation duration of 40 min and steam flow rate of 2.67 mL/min. The optimum conditions result in an activated carbon with an iodine number of 1048 mg/g and a yield of 40%, and the BET surface area evaluated using nitrogen adsorption isotherm is 1493 m2/g, with total pore volume of 1.242 cm3/g. And the pore structure of activated carbon regenerated is mainly composed of micropores and a small amount of mesopores.
基金Supported by Guizhou Provincial Project for Modernization and Industrialization of Traditional Chinese Medicine(QKHZY[2012]5001-5)
文摘[Objectives] The aim was to determine the optimum process for the extraction of volatile oil from Alpinia zerumbet fruit.[Methods]Steam distillation was used to extract volatile oil from A. zerumbet fruit. Based on the single factor tests,an orthogonal test was designed to explore the effects of solid-liquid ratio,soaking time,extraction time and grinding degree of material on the extraction rate. The composition of volatile oil from A. zerumbet fruit was analyzed using gas chromatography-mass spectrometry( GC-MS),and the relative mass fraction of each component was determined by peak area normalization. [Results] With volatile oil yield as the index,the optimum extraction process was determined: solid to liquid ratio of 1∶ 10,soaking time of 0. 5 h,grinding degree of passing through 24-mesh sieve and extraction time of 5 h. A total of 29 compounds were isolated. Among them,the contents of α-terpinene( 24. 894%),1,8-terpadiene( 15. 527%) andα-pinene( 6. 982%) were relatively high. [Conclusions]The optimized extraction process for volatile oil from A. zerumbet fruit is stable and reasonable. Under the optimum extraction process,the extraction effect of volatile oil from A. zerumbet fruit was the best. The chemical components of volatile oil from A. zerumbet fruit were determined by GC-MS as α-terpinene( 24. 894%),1,8-terpadiene( 15. 527%) and α-pinene( 6. 982%).
基金Thermodynamic calculation of defluorination process using the HSC Chemistry 10 was supported by Prof.Huan Li,from the Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences(CAS)The financial support from the National Natural Science Foundation of China(No.52104271)+2 种基金Natural Science Foundation of Henan,China(No.242300421222)the Open Project Program of Key Laboratory of Metallurgical Emission Reduction & Resources Recycling(Anhui University of Technology),Ministry of Education(No.JKF24-02)the Project of Zhongyuan Critical Metals Laboratory(No.GJJSGFYQ202416)were greatly acknowledged
文摘Lepidolites are important carriers of Li ores.Because of the strong positive correlation between the presence of Li and F,Li extracted from lepidolite must be defluorinated.Moreover,synergistically extracting Li,Rb,and Cs is important for the comprehensive utilization of lepidolite.Steam roasting converts F to HF without introducing impurities.In this study,the effects of steam roasting on Li activation and the synergistic extraction of Rb and Cs were investigated during the defluorination process.Notably,the defluorination mechanism and migration behavior of F during steam roasting were revealed based on qualitative and quantitative analyses of the liquid and corresponding solid phases.Furthermore,density functional theory calculations were used to investigate the pathways and behaviors of defluorination and the removal behavior of F atoms connected to Al and Li sites,revealing that the F atoms on the(010)crystal surface were easily replaced by water molecules,thereby releasing surface F atoms.Under the optimal roasting conditions,the defluorination efficiency of lepidolite was 91.08%at 880℃for 1 h.Subsequently,the Li encapsulated in the crystal lattice,as well as Rb and Cs,was activated and leached using optimal sulfuric acid leaching.The leaching efficiencies of Li,Rb,and Cs were 97.37%,97.77%,and 97.19%,respectively at 120℃for 2 h.This study provides a comprehensive and systematic perspective on the defluorination and comprehensive utilization of lepidolite,providing a comprehensive,clean,efficient,green,and low-C lepidolite Li extraction process.
基金supported by the National Natural Science Foundation of China(No.31371826)the China Postdoctoral Science Foundation(No.2016M592002)
文摘Aroma of Chinese steamed bread（CSB） is one of the important parameters that determines the overall quality attributes and consumer acceptance. However, the aroma profile of CSB still remains poorly understood, mainly because of relying on only a single method for aroma extraction in previous studies. Therefore, the objective of this study was to determine the volatile aroma compounds of five different samples of CSB using three different aroma extraction methods, namely solid-phase microextraction（SPME）, simultaneous distillation–extraction（SDE）, and purge and trap（PT）. All samples showed a unique aroma profile, which could be attributed to their unique microbial consortia.（E）-2-Nonenal and（E,E）-2,4-decadienal were the most prevalent aromatic compounds revealed by SDE, which have not been reported previously, while ethanol and acetic acid proved to be the most dominant compounds by both SPME and PT. Our approach of combining three different aroma extraction methods provided better insights into the aroma profile of CSB, which had remained largely unknown in previous studies.
基金supported by the National Natural Science Foundation of China under Grant number U2243222,42071413,and 41971397.
文摘Deep learning algorithms show good prospects for remote sensingflood monitoring.They mostly rely on huge amounts of labeled data.However,there is a lack of available labeled data in actual needs.In this paper,we propose a high-resolution multi-source remote sensing dataset forflood area extraction:GF-FloodNet.GF-FloodNet contains 13388 samples from Gaofen-3(GF-3)and Gaofen-2(GF-2)images.We use a multi-level sample selection and interactive annotation strategy based on active learning to construct it.Compare with otherflood-related datasets,GF-FloodNet not only has a spatial resolution of up to 1.5 m and provides pixel-level labels,but also consists of multi-source remote sensing data.We thoroughly validate and evaluate the dataset using several deep learning models,including quantitative analysis,qualitative analysis,and validation on large-scale remote sensing data in real scenes.Experimental results reveal that GF-FloodNet has significant advantages by multi-source data.It can support different deep learning models for training to extractflood areas.There should be a potential optimal boundary for model training in any deep learning dataset.The boundary seems close to 4824 samples in GF-FloodNet.We provide GF-FloodNet at https://www.kaggle.com/datasets/pengliuair/gf-floodnet and https://pan.baidu.com/s/1vdUCGNAfFwG5UjZ9RLLFMQ?pwd=8v6o.
