近年来,异构数据的转换和集成是企业应用集成(EAI)一个重要部分。对异构数据库之间的数据转换和共享也成为其主要研究方向之一。在参考了其他数据转换模型的基础上,提出了基于XML文件的数据转换模型DCMHD(Data Conversion Model of Hete...近年来,异构数据的转换和集成是企业应用集成(EAI)一个重要部分。对异构数据库之间的数据转换和共享也成为其主要研究方向之一。在参考了其他数据转换模型的基础上,提出了基于XML文件的数据转换模型DCMHD(Data Conversion Model of Heterogeneous Database)。通过模型自定义数据类型,数据库和数据库之间的数据转换可以简化为数据库与系统之间的数据转换,显著提高了系统的稳定性和可扩展性;并且采用XML作为传输介质,易于异构数据的传输和共享,最后给出了模型的主要实现。展开更多
Nitrous acid(HONO)is an important source of hydrogen oxides(HOx),which affects air quality,the atmospheric oxidation capacity,and human health.Here,we present ambient measurements of the HONO concentrations in Zhuhai,...Nitrous acid(HONO)is an important source of hydrogen oxides(HOx),which affects air quality,the atmospheric oxidation capacity,and human health.Here,we present ambient measurements of the HONO concentrations in Zhuhai,a coastal city in Southern China,from February 7 to March 15,2021.The campaign was classified into two periods during(P1)and after(P2)the Spring Festival holidays.The average HONO mixing ratio during P2(1.19±0.85 ppbv)was much higher than that during P1(0.24±0.18 ppbv),likely due to the contribution of homogeneous HONO formation.During nighttime,the heterogeneous conversion rate during P2(0.0089/hr)was considerably higher than that during P1(0.0057/hr),suggesting a higher heterogeneous NO_(2) conversion potential.However,the heterogeneous NO_(2) conversion was the dominant way during P1 with a high percentage of 88%,while comparable ratios of heterogeneous and homogeneous formation were found(54%vs.46%)during P2,indicating that the homogeneous formation was also important during P2.During daytime,homogeneous reaction was the major known pathway,with a contribution of 16%during P1 and 27%during P2,leaving large unknown HONO sources which reasonably correlated with the photo-enhanced NO_(2) conversion.Two case scenarios were additionally explored,showing that there might be a primary emission source during one scenario(February 17-18)and vehicle emissions might be the major unknown HONO source for another scenario(March 3–5).The results suggest that large unknown daytime sources still exist which need more future ambient and laboratory studies.展开更多
文摘近年来,异构数据的转换和集成是企业应用集成(EAI)一个重要部分。对异构数据库之间的数据转换和共享也成为其主要研究方向之一。在参考了其他数据转换模型的基础上,提出了基于XML文件的数据转换模型DCMHD(Data Conversion Model of Heterogeneous Database)。通过模型自定义数据类型,数据库和数据库之间的数据转换可以简化为数据库与系统之间的数据转换,显著提高了系统的稳定性和可扩展性;并且采用XML作为传输介质,易于异构数据的传输和共享,最后给出了模型的主要实现。
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.42175115,41775117)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515011864)+4 种基金the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030004)the Science and Technology Innovation Committee of Guangzhou(No.201803030010)the Scientific and Technological Innovation Team Project of Guangzhou Joint Research Center of Atmospheric Sciences,Science and Technology Program of Guangdong Province(Science and Technology Innovation Platform Category)(No.2019B121201002)the Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(No.2020B1212060025)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(22qntd1907).
文摘Nitrous acid(HONO)is an important source of hydrogen oxides(HOx),which affects air quality,the atmospheric oxidation capacity,and human health.Here,we present ambient measurements of the HONO concentrations in Zhuhai,a coastal city in Southern China,from February 7 to March 15,2021.The campaign was classified into two periods during(P1)and after(P2)the Spring Festival holidays.The average HONO mixing ratio during P2(1.19±0.85 ppbv)was much higher than that during P1(0.24±0.18 ppbv),likely due to the contribution of homogeneous HONO formation.During nighttime,the heterogeneous conversion rate during P2(0.0089/hr)was considerably higher than that during P1(0.0057/hr),suggesting a higher heterogeneous NO_(2) conversion potential.However,the heterogeneous NO_(2) conversion was the dominant way during P1 with a high percentage of 88%,while comparable ratios of heterogeneous and homogeneous formation were found(54%vs.46%)during P2,indicating that the homogeneous formation was also important during P2.During daytime,homogeneous reaction was the major known pathway,with a contribution of 16%during P1 and 27%during P2,leaving large unknown HONO sources which reasonably correlated with the photo-enhanced NO_(2) conversion.Two case scenarios were additionally explored,showing that there might be a primary emission source during one scenario(February 17-18)and vehicle emissions might be the major unknown HONO source for another scenario(March 3–5).The results suggest that large unknown daytime sources still exist which need more future ambient and laboratory studies.
