A systematic study of coupled heat and mass transfer in unsaturated soils under complex boundary conditions was carried out and a mathematical model of heat and mass transfer in unsaturated soils was established by no...A systematic study of coupled heat and mass transfer in unsaturated soils under complex boundary conditions was carried out and a mathematical model of heat and mass transfer in unsaturated soils was established by non equilibrium thermodynamic theory. The gradient of volumetric moisture content, the gradient of temperature, the salt mass concentration and vapor pressure were the primary driving forces influencing the process of heat and mass transfer in unsaturated soils. Based on the thermodynamic analysis and the mass and energy conservation principles, a set of mass and energy equations were developed. The initial and boundary conditions of soil column for one dimension were also given out.展开更多
A new compound 1,1?-bis(3-pyridyl)-propylene(3,7-diformyl-N-ethylpheno- thiazinyl)ketone (C30H23N3O2S, Mr = 489.4) has been synthesized, and its crystal structure was determined by single-crystal X-ray diffraction met...A new compound 1,1?-bis(3-pyridyl)-propylene(3,7-diformyl-N-ethylpheno- thiazinyl)ketone (C30H23N3O2S, Mr = 489.4) has been synthesized, and its crystal structure was determined by single-crystal X-ray diffraction method. The crystal is of orthorhombic, space group Ima2 with a = 27.491(5), b = 11.942(2), c = 7.389(2) ?, V = 2425.8(7) ?3, Z = 8, Dc = 1.340 g/cm3, μ = 0.167 mm-1, F(000) = 1024, the final R = 0.0363 and wR = 0.0869 for 2054 unique reflections with Rint = 0.0254. The structural determination shows that the molecule assumes a butterfly configuration with nearly planar wings. In addition, the electrochemical study indicates that there is a high electronic delocalization in the molecule.展开更多
In linewith advicefrom internationalfinancial institutions, China introduced a three-pillar pension system in 1997. However, it performs badly, with high contribution levels, the ‘funded’ contributionsbeing used for...In linewith advicefrom internationalfinancial institutions, China introduced a three-pillar pension system in 1997. However, it performs badly, with high contribution levels, the ‘funded’ contributionsbeing used forcurrent expenditures,and delaysinpension payments. The problemsareoften ascribed tothe remaining elements of pay-as-you-go (PAYG) present in thesystem. Thispaper, however, arguesthat the advantagesofa fully-funded system (FF) havebeen exaggerated. The higher relative return of the PAYG system in China justifies a PAYG pension system forChina. It is arguedthat theproblemsoftheChinesepension system are not caused by the use of PAYG butbytheneed to finance transition costs and conditions particularto the pension system in China, notablyincomplete contribution coverage, a low pension age, and a high replacement rate. Itisthesefactors, and therateofgrowth ofoutput, which determine the viabilityof theChinese pension system.展开更多
文摘A systematic study of coupled heat and mass transfer in unsaturated soils under complex boundary conditions was carried out and a mathematical model of heat and mass transfer in unsaturated soils was established by non equilibrium thermodynamic theory. The gradient of volumetric moisture content, the gradient of temperature, the salt mass concentration and vapor pressure were the primary driving forces influencing the process of heat and mass transfer in unsaturated soils. Based on the thermodynamic analysis and the mass and energy conservation principles, a set of mass and energy equations were developed. The initial and boundary conditions of soil column for one dimension were also given out.
基金This work was supported by the National Natural Science Foundation of China (50272001, 50335050) and the Committee of Education of Anhui Province (2004KJ020, 2003KJ218)
文摘A new compound 1,1?-bis(3-pyridyl)-propylene(3,7-diformyl-N-ethylpheno- thiazinyl)ketone (C30H23N3O2S, Mr = 489.4) has been synthesized, and its crystal structure was determined by single-crystal X-ray diffraction method. The crystal is of orthorhombic, space group Ima2 with a = 27.491(5), b = 11.942(2), c = 7.389(2) ?, V = 2425.8(7) ?3, Z = 8, Dc = 1.340 g/cm3, μ = 0.167 mm-1, F(000) = 1024, the final R = 0.0363 and wR = 0.0869 for 2054 unique reflections with Rint = 0.0254. The structural determination shows that the molecule assumes a butterfly configuration with nearly planar wings. In addition, the electrochemical study indicates that there is a high electronic delocalization in the molecule.
文摘In linewith advicefrom internationalfinancial institutions, China introduced a three-pillar pension system in 1997. However, it performs badly, with high contribution levels, the ‘funded’ contributionsbeing used forcurrent expenditures,and delaysinpension payments. The problemsareoften ascribed tothe remaining elements of pay-as-you-go (PAYG) present in thesystem. Thispaper, however, arguesthat the advantagesofa fully-funded system (FF) havebeen exaggerated. The higher relative return of the PAYG system in China justifies a PAYG pension system forChina. It is arguedthat theproblemsoftheChinesepension system are not caused by the use of PAYG butbytheneed to finance transition costs and conditions particularto the pension system in China, notablyincomplete contribution coverage, a low pension age, and a high replacement rate. Itisthesefactors, and therateofgrowth ofoutput, which determine the viabilityof theChinese pension system.
