主权评级的公正性问题是国际社会关注的一个焦点。首先,文章通过运用面板线性回归(Panel Linear Regression)和有序概率(Ordered Probit)方法,从长短期两个角度研究了主权评级的决定因素。研究结果表明一国的宏观因素对评级具有长期影响...主权评级的公正性问题是国际社会关注的一个焦点。首先,文章通过运用面板线性回归(Panel Linear Regression)和有序概率(Ordered Probit)方法,从长短期两个角度研究了主权评级的决定因素。研究结果表明一国的宏观因素对评级具有长期影响,而对外债务和政府收支对评级具有短期影响。文章对大中华区、G7和金砖五国进行了的主权评级的拟合和预测,结果表明我国在2011年以前存在被低估现象,但2012年后却存在被高估现象。最后,文章建议我国在被穆迪降级之后,要保持适度警惕,采取必要政策和措施,以防降级事件的再次发生。展开更多
Quality of soil humic substances and compost quality was assessed using different techniques of fluorescence spectroscopy. Emission, excitation, synchronous and emission-excitation matrix help us to characterize diffe...Quality of soil humic substances and compost quality was assessed using different techniques of fluorescence spectroscopy. Emission, excitation, synchronous and emission-excitation matrix help us to characterize different fluorophores in humic substances molecule. Content of stabile carbon forms in soil was assessed by humic substances fractionation. Content of labile water extractable carbon and nitrogen was determined by analyzer Shimadzu TOC-VCSH with chemo-luminescent detection in infrared spectral region. Results showed that compost amendment caused changes in both stabile （recalcitrant） and labile carbon content. Humic substances isolated from compost consist mainly of simple structural components of wide molecular heterogeneity and low molecular weight. Humification degree and content of conjugated fluorophores in compost was lower compared with stabile soil humic substances. The last contained more conjugated aromatic π-electron systems with electron-withdrawing functional groups, which are responsible for the fluorescence shift to lower energy levels or longer wavelengths.展开更多
文摘主权评级的公正性问题是国际社会关注的一个焦点。首先,文章通过运用面板线性回归(Panel Linear Regression)和有序概率(Ordered Probit)方法,从长短期两个角度研究了主权评级的决定因素。研究结果表明一国的宏观因素对评级具有长期影响,而对外债务和政府收支对评级具有短期影响。文章对大中华区、G7和金砖五国进行了的主权评级的拟合和预测,结果表明我国在2011年以前存在被低估现象,但2012年后却存在被高估现象。最后,文章建议我国在被穆迪降级之后,要保持适度警惕,采取必要政策和措施,以防降级事件的再次发生。
文摘Quality of soil humic substances and compost quality was assessed using different techniques of fluorescence spectroscopy. Emission, excitation, synchronous and emission-excitation matrix help us to characterize different fluorophores in humic substances molecule. Content of stabile carbon forms in soil was assessed by humic substances fractionation. Content of labile water extractable carbon and nitrogen was determined by analyzer Shimadzu TOC-VCSH with chemo-luminescent detection in infrared spectral region. Results showed that compost amendment caused changes in both stabile （recalcitrant） and labile carbon content. Humic substances isolated from compost consist mainly of simple structural components of wide molecular heterogeneity and low molecular weight. Humification degree and content of conjugated fluorophores in compost was lower compared with stabile soil humic substances. The last contained more conjugated aromatic π-electron systems with electron-withdrawing functional groups, which are responsible for the fluorescence shift to lower energy levels or longer wavelengths.
