^(199)Hg NHR spectra of 18 Schiff base type arylmercury compounds have been studied.It was further confirmed that in the molecule of XC_6H_4CH=NC_6H_3-2-HgC1-4-CH_3 there exists an intramolecular N→Hg coordination vi...^(199)Hg NHR spectra of 18 Schiff base type arylmercury compounds have been studied.It was further confirmed that in the molecule of XC_6H_4CH=NC_6H_3-2-HgC1-4-CH_3 there exists an intramolecular N→Hg coordination via a four-membered ring.For the series of XC_6H_4CH=NC_6H_3-2-HgCl-4-CH_3(X is a para-or mera-substituent),there is a good linear correlation between δ^(199)Hg and Hammett's o constants.The influence of substituents of C-pheny1 ring on the δ ^(199)Hg can be explained in terms of the intramolecular N→Hg coordination.展开更多
随着全球变暖,复合型气候事件的发生特征逐渐成为近年来研究的热点。本研究采用第五代欧洲中期天气预报中心(The European Centre for Medium-Range Weather Forecasts,ECMWF)全球气候大气再分析(ECMWF Reanalysis v5,ERA5)数据中包含...随着全球变暖,复合型气候事件的发生特征逐渐成为近年来研究的热点。本研究采用第五代欧洲中期天气预报中心(The European Centre for Medium-Range Weather Forecasts,ECMWF)全球气候大气再分析(ECMWF Reanalysis v5,ERA5)数据中包含的日最高温和日降水数据分析了中国1982—2022年复合干热和湿热事件的发生特征,并引入了震级指数衡量复合事件的强度,结果显示复合事件的持续时间、频次和震级均显示不同程度的增长,其中复合湿热事件(CHTRE)的增长幅度均高于复合干热事件(CHTDE);极端型复合干热和湿热事件上升趋势最为明显(分别为0.24%和0.11%),高温主导了复合事件的变化趋势;6—8月是中国复合干热/复合湿热事件发生的主要月份,其中极端型复合事件多集中在7月。由于极端事件可能会随着全球持续变暖而增加,因此了解复合事件的发生特征对于增强中国抵御气候变化影响的能力至关重要。展开更多
文摘^(199)Hg NHR spectra of 18 Schiff base type arylmercury compounds have been studied.It was further confirmed that in the molecule of XC_6H_4CH=NC_6H_3-2-HgC1-4-CH_3 there exists an intramolecular N→Hg coordination via a four-membered ring.For the series of XC_6H_4CH=NC_6H_3-2-HgCl-4-CH_3(X is a para-or mera-substituent),there is a good linear correlation between δ^(199)Hg and Hammett's o constants.The influence of substituents of C-pheny1 ring on the δ ^(199)Hg can be explained in terms of the intramolecular N→Hg coordination.
文摘随着全球变暖,复合型气候事件的发生特征逐渐成为近年来研究的热点。本研究采用第五代欧洲中期天气预报中心(The European Centre for Medium-Range Weather Forecasts,ECMWF)全球气候大气再分析(ECMWF Reanalysis v5,ERA5)数据中包含的日最高温和日降水数据分析了中国1982—2022年复合干热和湿热事件的发生特征,并引入了震级指数衡量复合事件的强度,结果显示复合事件的持续时间、频次和震级均显示不同程度的增长,其中复合湿热事件(CHTRE)的增长幅度均高于复合干热事件(CHTDE);极端型复合干热和湿热事件上升趋势最为明显(分别为0.24%和0.11%),高温主导了复合事件的变化趋势;6—8月是中国复合干热/复合湿热事件发生的主要月份,其中极端型复合事件多集中在7月。由于极端事件可能会随着全球持续变暖而增加,因此了解复合事件的发生特征对于增强中国抵御气候变化影响的能力至关重要。
