Particulate levoglucosan is an important tracer for biomass burning emission in ambient air.However,recent studies question its reliability as a biomass burning tracer in Chinesemega cities due to important contributi...Particulate levoglucosan is an important tracer for biomass burning emission in ambient air.However,recent studies question its reliability as a biomass burning tracer in Chinesemega cities due to important contribution from potential non-biomass burning sources,such as cooking.To address this,we examined the dynamic variation and sources of levoglucosan using a chemical ionization mass spectrometer and other advanced instruments during Beijing’s summer of 2021.The average mass concentration of levoglucosan and its isomer(C_(6)H_(10)O_(5))was 0.025±0.014μg/m^(3),constituting 0.55%±0.32%of total organic carbon(OC)in this campaign.Despite cooking emissions contributing significantly to the organic aerosol(OA,20%),levoglucosan and its isomers correlated more strongly with biomass-burning related tracers(R>0.6),black carbon(R=0.72)and less so with cooking-related sources(R=0.3).This indicates that levoglucosan is primarily dominated by biomass-burning emissions rather than cooking in Beijing’s urban areas during summertime.The diurnal variation of levoglucosan concentrations highlighted the importance of daytime and nocturnal biomass burning emissions during polluted periods in Beijing.Using levoglucosan as a tracer to quantify the biomass burning OC(BBOC),we found good agreement on the time series of BBOC between the tracermethod and other independent source apportionmentmethod.This reaffirms the reliability of levoglucosan as a biomass burning tracer.Biomass burning contributed an average of 7%-8%to OC,highlighting its significant impact on Beijing’s summer air quality.Our study enhances understanding of biomass burning influences on ambient aerosol in typical urban areas.展开更多
This paper introduces the origin and research status of traditional Yaoqu(Chinese medicinal koji)in China,and advances in the research of preparation and development of pure functional Yaoqu.The study results showed t...This paper introduces the origin and research status of traditional Yaoqu(Chinese medicinal koji)in China,and advances in the research of preparation and development of pure functional Yaoqu.The study results showed that the quality of the products was significantly improved when pure Yaoqu was used as saccharifying agent in the brewing of sake,soy sauce and other products.Based on the high saccharification performance and special functional components,Yaoqu can be applied to the development of fermented food.展开更多
Volatile organic compounds(VOCs)oxidation processes play a very important role in atmospheric chemistry,and the chemical reactions are expressed in various manners in chemical mechanisms.To gain an improved understand...Volatile organic compounds(VOCs)oxidation processes play a very important role in atmospheric chemistry,and the chemical reactions are expressed in various manners in chemical mechanisms.To gain an improved understanding of VOCs evolution during oxidation processes and evaluate the discrepancies of VOCs oxidation schemes among different mechanisms,we used the total VOC reactivity as a diagnostic and evaluated tool to explore the differences for six widely used chemical mechanisms.We compared the total VOC reactivity evolution under high-NO_(x)xconditions for several sets of precursors,including n-pentane,toluene,ethene,isoprene and a mixture of 57 Photochemical Assessment Monitoring Stations(PAMS)species in a 0-D photochemical box model.Inter-comparison of total VOC reactivity of individual precursor simulations showed discrepancies to different extent of the oxidation schemes among the studied mechanisms,which are mainly attributed to the different lumping approaches for organic species.The PAMS simulation showed smaller discrepancy than individual precursor cases in terms of total VOC reactivity.SAPRC07 and RACM2 performances are found to better match the MCM for simulation of total VOC reactivity.Evidences suggest that the performance in simulating secondary organic products,OH concentrations and NO_(x)concentrations are related to the OH reactivity discrepancies among various chemical mechanisms.Information in this study can be used in selection of chemical mechanisms to better model OH reactivity in different environments.The results in this study also provide directions to further improve the ability in modelling total VOC reactivity with the chemical mechanisms.展开更多
Historical forest fire risk databases are vital for evaluating the effectiveness of past forest management approaches,enhancing forest fire warnings and emergency response capabilities,and accurately budgeting potenti...Historical forest fire risk databases are vital for evaluating the effectiveness of past forest management approaches,enhancing forest fire warnings and emergency response capabilities,and accurately budgeting potential carbon emissions resulting from fires.However,due to the unavailability of spatial information technology,such databases are extremely difficult to build reliably and completely in the non-satellite era.This study presented an improved forest fire risk reconstruction framework that integrates a deep learning-based time series prediction model and spatial interpolation to address the challenge in Sichuan Province,southwestern China.First,the forest fire danger index(FFDI)was improved by supplementing slope and aspect information.We compared the performances of three time series models,namely,the autoregressive integrated moving average(ARIMA),Prophet and long short-term memory(LSTM)in predicting the modified forest fire danger index(MFFDI).The bestperforming model was used to retrace the MFFDI of individual stations from 1941 to 1970.Following this,the Anusplin spatial interpolation method was used to map the distributions of the MFFDI at five-year intervals,which were then subjected to weighted overlay with the distance-to-river layer to generate forest fire risk maps for reconstructing the forest fire danger database.The results revealed LSTM as the most accurate in fitting and predicting the historical MFFDI,with a fitting determination coefficient(R^2)of 0.709,mean square error(MSE)of0.047,and validation R^2 and MSE of 0.508 and 0.11,respectively.Independent validation of the predicted forest fire risk maps indicated that 5 out of 7 historical forest fire events were located in forest fire-prone areas,which is higher than the results determined from the original FFDI(2 out of 7).This proves the effectiveness of the improved MFFDI and indicates a high level of reliability of the historical forest fire risk reconstruction method proposed in this study.展开更多
As a plant resource, Osmanthus fragrans has both medicinal and edible effects. This paper reviews the active components and health-care functions of O. fragrans, and introduces the current research situation of O. fra...As a plant resource, Osmanthus fragrans has both medicinal and edible effects. This paper reviews the active components and health-care functions of O. fragrans, and introduces the current research situation of O. fragrans mixed wine. In addition, combined with the development of new products of plant-based flower wine, it analyzes the development prospects of O. fragrans mixed wine based on liquor and spirits.展开更多
基金supported by the National Key R&D Program of China(Nos.2022YFC3701000 and 2021YFA1601800)the National Natural Science Foundation of China(Nos.42230701 and 42375105)+1 种基金the Foundation for Program of Science and Technology Research(No.2024A1515011937)Guangdong Foundation for Program of Science and Technology Research(No.2023B1212060049).
文摘Particulate levoglucosan is an important tracer for biomass burning emission in ambient air.However,recent studies question its reliability as a biomass burning tracer in Chinesemega cities due to important contribution from potential non-biomass burning sources,such as cooking.To address this,we examined the dynamic variation and sources of levoglucosan using a chemical ionization mass spectrometer and other advanced instruments during Beijing’s summer of 2021.The average mass concentration of levoglucosan and its isomer(C_(6)H_(10)O_(5))was 0.025±0.014μg/m^(3),constituting 0.55%±0.32%of total organic carbon(OC)in this campaign.Despite cooking emissions contributing significantly to the organic aerosol(OA,20%),levoglucosan and its isomers correlated more strongly with biomass-burning related tracers(R>0.6),black carbon(R=0.72)and less so with cooking-related sources(R=0.3).This indicates that levoglucosan is primarily dominated by biomass-burning emissions rather than cooking in Beijing’s urban areas during summertime.The diurnal variation of levoglucosan concentrations highlighted the importance of daytime and nocturnal biomass burning emissions during polluted periods in Beijing.Using levoglucosan as a tracer to quantify the biomass burning OC(BBOC),we found good agreement on the time series of BBOC between the tracermethod and other independent source apportionmentmethod.This reaffirms the reliability of levoglucosan as a biomass burning tracer.Biomass burning contributed an average of 7%-8%to OC,highlighting its significant impact on Beijing’s summer air quality.Our study enhances understanding of biomass burning influences on ambient aerosol in typical urban areas.
基金Supported by International Cooperation Project of National Key Research Program"Research on Expression Regulation of Key Genes of Characteristic Microorganisms in Chinese and Japanese Koji and Quality Improvement of Chinese Distiller's Yeast" (2018YFE0127400)Open Project of National New Antibiotic Culture Collection and Management Center of Chengdu University"Analysis of Physical and Chemical Characteristics of Liquor Koji and Screening of Functional Microorganisms" (CCSIIA202202).
文摘This paper introduces the origin and research status of traditional Yaoqu(Chinese medicinal koji)in China,and advances in the research of preparation and development of pure functional Yaoqu.The study results showed that the quality of the products was significantly improved when pure Yaoqu was used as saccharifying agent in the brewing of sake,soy sauce and other products.Based on the high saccharification performance and special functional components,Yaoqu can be applied to the development of fermented food.
基金supported by the National Natural Science Foundation of China(No.41877302)Guangdong Natural Science Funds for Distinguished Young Scholar(No.2018B030306037)+2 种基金the National Key R&D Plan of China(No.2019YFE0106300)Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06N263)supported by the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(No.2019B121205004)
文摘Volatile organic compounds(VOCs)oxidation processes play a very important role in atmospheric chemistry,and the chemical reactions are expressed in various manners in chemical mechanisms.To gain an improved understanding of VOCs evolution during oxidation processes and evaluate the discrepancies of VOCs oxidation schemes among different mechanisms,we used the total VOC reactivity as a diagnostic and evaluated tool to explore the differences for six widely used chemical mechanisms.We compared the total VOC reactivity evolution under high-NO_(x)xconditions for several sets of precursors,including n-pentane,toluene,ethene,isoprene and a mixture of 57 Photochemical Assessment Monitoring Stations(PAMS)species in a 0-D photochemical box model.Inter-comparison of total VOC reactivity of individual precursor simulations showed discrepancies to different extent of the oxidation schemes among the studied mechanisms,which are mainly attributed to the different lumping approaches for organic species.The PAMS simulation showed smaller discrepancy than individual precursor cases in terms of total VOC reactivity.SAPRC07 and RACM2 performances are found to better match the MCM for simulation of total VOC reactivity.Evidences suggest that the performance in simulating secondary organic products,OH concentrations and NO_(x)concentrations are related to the OH reactivity discrepancies among various chemical mechanisms.Information in this study can be used in selection of chemical mechanisms to better model OH reactivity in different environments.The results in this study also provide directions to further improve the ability in modelling total VOC reactivity with the chemical mechanisms.
基金the following grants:The National Key R&D Program of China(2019YFA0606600)the Natural Science Foundation of China(31971577)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Historical forest fire risk databases are vital for evaluating the effectiveness of past forest management approaches,enhancing forest fire warnings and emergency response capabilities,and accurately budgeting potential carbon emissions resulting from fires.However,due to the unavailability of spatial information technology,such databases are extremely difficult to build reliably and completely in the non-satellite era.This study presented an improved forest fire risk reconstruction framework that integrates a deep learning-based time series prediction model and spatial interpolation to address the challenge in Sichuan Province,southwestern China.First,the forest fire danger index(FFDI)was improved by supplementing slope and aspect information.We compared the performances of three time series models,namely,the autoregressive integrated moving average(ARIMA),Prophet and long short-term memory(LSTM)in predicting the modified forest fire danger index(MFFDI).The bestperforming model was used to retrace the MFFDI of individual stations from 1941 to 1970.Following this,the Anusplin spatial interpolation method was used to map the distributions of the MFFDI at five-year intervals,which were then subjected to weighted overlay with the distance-to-river layer to generate forest fire risk maps for reconstructing the forest fire danger database.The results revealed LSTM as the most accurate in fitting and predicting the historical MFFDI,with a fitting determination coefficient(R^2)of 0.709,mean square error(MSE)of0.047,and validation R^2 and MSE of 0.508 and 0.11,respectively.Independent validation of the predicted forest fire risk maps indicated that 5 out of 7 historical forest fire events were located in forest fire-prone areas,which is higher than the results determined from the original FFDI(2 out of 7).This proves the effectiveness of the improved MFFDI and indicates a high level of reliability of the historical forest fire risk reconstruction method proposed in this study.
文摘As a plant resource, Osmanthus fragrans has both medicinal and edible effects. This paper reviews the active components and health-care functions of O. fragrans, and introduces the current research situation of O. fragrans mixed wine. In addition, combined with the development of new products of plant-based flower wine, it analyzes the development prospects of O. fragrans mixed wine based on liquor and spirits.
