采用吉林省国家环境空气自动监测站点的臭氧(O3)和气象(气压、气温、相对湿度和风速)监测数据,探讨吉林省臭氧时空特征及其与气象要素的关系。结果表明:2017年吉林省O3最大8 h 90百分位浓度呈现"中间高,两边低"的片状分布;201...采用吉林省国家环境空气自动监测站点的臭氧(O3)和气象(气压、气温、相对湿度和风速)监测数据,探讨吉林省臭氧时空特征及其与气象要素的关系。结果表明:2017年吉林省O3最大8 h 90百分位浓度呈现"中间高,两边低"的片状分布;2017年吉林省各季节O3最大8 h平均浓度从高到低依次为:夏季>春季>秋季>冬季;2017年吉林省O3浓度月变化和日变化均呈单峰型,月变化中于5月出现峰值,12月出现谷值;日变化中于上午7∶00出现谷值,下午15∶00出现峰值;从臭氧超标率来看,当970 h Pa<平均气压≤980 h Pa、平均温度>25℃、最高气温>30℃、日较差>16℃、40%<相对湿度≤50%以及3 m/s<平均风速≤3.5 m/s时,吉林省易发生臭氧污染。展开更多
Code-switching in English-teaching has been receiving growing atten-tion in recent years. Not being viewed as a random phenomenon, it has come to be seen as a highly purposeful activity. The present authors focus thei...Code-switching in English-teaching has been receiving growing atten-tion in recent years. Not being viewed as a random phenomenon, it has come to be seen as a highly purposeful activity. The present authors focus their study on Code-switching not in the language classroom but in authentic Lingual speech conlmunities.展开更多
Diarylethene derivatives are a class of fascinating photochromic materials because of their open and closed isomers with different absorption spectra and many other characteristics.To reveal the detailed structure and...Diarylethene derivatives are a class of fascinating photochromic materials because of their open and closed isomers with different absorption spectra and many other characteristics.To reveal the detailed structure and optoelectronic properties as well as the effect of metal centres and substituents on them,a systematic study on a series of diarylethene derivatives and their Re(I),Pt(II),and Ir(III) complexes was performed via theoretical calculation.The optimized geometries,electronic properties,frontier molecular orbitals,ionization potentials,electron affinities,reorganization energies,and absorption spectra for both of their open-and closed-isomers have been calculated and analyzed.Metal-coordination and substituents exhibit great influence on the photophysical,charge-injection and-transporting characteristics.In addition,the binding of F-with the boron atom of dimesitylboryl group through Lewis acid/base interactions also induces great changes of structural,photophysical and electronic properties for these diarylethene derivatives,and consequently the compound with the substituent of dimesitylboryl group can be used as selective near-infrared phosphorescent F-probe.展开更多
文摘采用吉林省国家环境空气自动监测站点的臭氧(O3)和气象(气压、气温、相对湿度和风速)监测数据,探讨吉林省臭氧时空特征及其与气象要素的关系。结果表明:2017年吉林省O3最大8 h 90百分位浓度呈现"中间高,两边低"的片状分布;2017年吉林省各季节O3最大8 h平均浓度从高到低依次为:夏季>春季>秋季>冬季;2017年吉林省O3浓度月变化和日变化均呈单峰型,月变化中于5月出现峰值,12月出现谷值;日变化中于上午7∶00出现谷值,下午15∶00出现峰值;从臭氧超标率来看,当970 h Pa<平均气压≤980 h Pa、平均温度>25℃、最高气温>30℃、日较差>16℃、40%<相对湿度≤50%以及3 m/s<平均风速≤3.5 m/s时,吉林省易发生臭氧污染。
文摘Code-switching in English-teaching has been receiving growing atten-tion in recent years. Not being viewed as a random phenomenon, it has come to be seen as a highly purposeful activity. The present authors focus their study on Code-switching not in the language classroom but in authentic Lingual speech conlmunities.
基金supported by the National Basic Research Program of China (973 Program,2009CB930601 and 2012CB933301)National Natural Science Foundation of China (21174064,21171098)+4 种基金Natural Science Fund for Colleges and Universities in Jiangsu Province(10KJB430010)the Ministry of Education of China (IRT1148)Key Projects in Jiangsu Province for International Cooperation (BZ2010043)Nanjing University of Posts and Telecommunications (NY210029)Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Diarylethene derivatives are a class of fascinating photochromic materials because of their open and closed isomers with different absorption spectra and many other characteristics.To reveal the detailed structure and optoelectronic properties as well as the effect of metal centres and substituents on them,a systematic study on a series of diarylethene derivatives and their Re(I),Pt(II),and Ir(III) complexes was performed via theoretical calculation.The optimized geometries,electronic properties,frontier molecular orbitals,ionization potentials,electron affinities,reorganization energies,and absorption spectra for both of their open-and closed-isomers have been calculated and analyzed.Metal-coordination and substituents exhibit great influence on the photophysical,charge-injection and-transporting characteristics.In addition,the binding of F-with the boron atom of dimesitylboryl group through Lewis acid/base interactions also induces great changes of structural,photophysical and electronic properties for these diarylethene derivatives,and consequently the compound with the substituent of dimesitylboryl group can be used as selective near-infrared phosphorescent F-probe.
