The atmospheric boundary layer （ABL） is an important physical characteristic of the Earth＇s atmosphere. Compared with the typical ABL, the ABL in arid regions has distinct features and is formed by particular mecha...The atmospheric boundary layer （ABL） is an important physical characteristic of the Earth＇s atmosphere. Compared with the typical ABL, the ABL in arid regions has distinct features and is formed by particular mechanisms. In this paper, the depth of the diurnal and nocturnal ABLs and their related thermodynamic features of land surface processes, including net radiation, the ground-air temperature difference and sensible heat flux, under typical summer and winter conditions are discussed on the basis of comprehensive observations of the ABL and thermodynamic processes at the land surface carried out in the extreme arid zone of Dunhuang. The relationships of the ABL depth in the development and maintenance stages with these thermodynamic features are also investigated. The results show that the depth of the ABL is closely correlated with the thermodynamic features in both development and maintenance stages and more energy is consumed in the development stage. Further analysis indicates that wind velocity also affects ABL development, especially the development of a stable boundary layer in winter. Taken together, the analysis results indicate that extremely strong thermodynamic processes at the land surface are the main driving factor for the formation of a deep ABL in an arid region.展开更多
A study on the transport characteristics of zinc in lou soil with phosphate at different concentrations was carried out by the method of step input. The effects of phosphate and temperature on zinc transport were stud...A study on the transport characteristics of zinc in lou soil with phosphate at different concentrations was carried out by the method of step input. The effects of phosphate and temperature on zinc transport were studied through analysing the diffusion-dispersion coefficients (D) and the retardation factor (R) obtained by the program CXTFIT. The results showed that D decreased and R increased with increasing concentration of phosphate so that it was difficult for zinc to break through the soil column, and zinc stopped to break through the column at high temperature. One order equation, double constant equation and the Elovich equation were all suitable for the description of zinc dynamica. Effects of phosphate and temperature on zinc transport were further confirmed by the analysis on pseudo-thermodynamic parameters of zinc transport.展开更多
The thermodynamic factor in diffusion in the L1_2-type non-stoichiometricintermetallic compounds Ni_3Ga and Pt_3In was derived from the experimentally measured activities ofGa and In, respectively. The results show th...The thermodynamic factor in diffusion in the L1_2-type non-stoichiometricintermetallic compounds Ni_3Ga and Pt_3In was derived from the experimentally measured activities ofGa and In, respectively. The results show that the thermodynamic factor in diffusion in the Ni_3Gaand Pt_3In compounds exhibits the maximum near the stoichiometric composition with the variation ofcomposition over the compound region. The values indicate strong interaction between Ni and Gaatoms, as well as Pt and In atoms, respectively, as expected in ordered alloys.展开更多
The present paper describes the energy analysis of a regenerative vapour power system. The regenerative steam turbines based on the Rankine cycle and comprised of vapour extractions have been used industrially since t...The present paper describes the energy analysis of a regenerative vapour power system. The regenerative steam turbines based on the Rankine cycle and comprised of vapour extractions have been used industrially since the beginning of the 20th century, particularly regarding the processes of electrical production. After having performed worked in the first stages of the turbine, part of the vapour is directed toward a regenerative exchanger and heats feedwater coming from the condenser. This process is known as regeneration, and the heat exchanger where the heat is transferred from steam is called a regenerator (or a feedwater heater). The profit in the output brought by regenerative rakings is primarily enabled by the lack of exchange of the tapped vapour reheating water with the low-temperature reservoir. The economic optimum is often fixed at seven extractions. One knows the Carnot relation, which is the best possible theoretical yield of a dual-temperature cycle;in a Carnot cycle, one makes the assumption that both compressions and expansions are isentropic. This article studies an ideal theoretical machine comprised of vapour extractions in which each cycle partial of tapped vapour obeys these same compressions and isentropic expansions.展开更多
The Complex permittivity spectra of glycol ether(GE)compounds such as ethylene glycol mono-methyl ether(EGME)with water mixture over entire concentration range and in temperature range of 10-25℃ have been determined ...The Complex permittivity spectra of glycol ether(GE)compounds such as ethylene glycol mono-methyl ether(EGME)with water mixture over entire concentration range and in temperature range of 10-25℃ have been determined using Time Domain Reflectometry(TDR)technique in the frequency range 10MHz to 50 GHz.The complex permittivity spectra for EGME-water were fitted in the Cole-Davidson model.The Static dielectric constant(ε_(0)^(E)),Relaxation time(τ),effective Kirkwood correlation factor(g_(eff)),excess permittivity(ε_(0)),thermodynamic parameters(activation enthalpy and activation entropy)and Bruggeman factor(f_(B))have been calculated by the nonlinear least square fit method.The intermolecular interactions between EGME-water binary mixtures suggest the nonlinear behavior of dielectric parameters.The contribution of hydrogen bonding interactions among the solute-solvent mixtures is confirmed by Excess properties and Bruggeman factor.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 40830957, 40805009)
文摘The atmospheric boundary layer （ABL） is an important physical characteristic of the Earth＇s atmosphere. Compared with the typical ABL, the ABL in arid regions has distinct features and is formed by particular mechanisms. In this paper, the depth of the diurnal and nocturnal ABLs and their related thermodynamic features of land surface processes, including net radiation, the ground-air temperature difference and sensible heat flux, under typical summer and winter conditions are discussed on the basis of comprehensive observations of the ABL and thermodynamic processes at the land surface carried out in the extreme arid zone of Dunhuang. The relationships of the ABL depth in the development and maintenance stages with these thermodynamic features are also investigated. The results show that the depth of the ABL is closely correlated with the thermodynamic features in both development and maintenance stages and more energy is consumed in the development stage. Further analysis indicates that wind velocity also affects ABL development, especially the development of a stable boundary layer in winter. Taken together, the analysis results indicate that extremely strong thermodynamic processes at the land surface are the main driving factor for the formation of a deep ABL in an arid region.
文摘A study on the transport characteristics of zinc in lou soil with phosphate at different concentrations was carried out by the method of step input. The effects of phosphate and temperature on zinc transport were studied through analysing the diffusion-dispersion coefficients (D) and the retardation factor (R) obtained by the program CXTFIT. The results showed that D decreased and R increased with increasing concentration of phosphate so that it was difficult for zinc to break through the soil column, and zinc stopped to break through the column at high temperature. One order equation, double constant equation and the Elovich equation were all suitable for the description of zinc dynamica. Effects of phosphate and temperature on zinc transport were further confirmed by the analysis on pseudo-thermodynamic parameters of zinc transport.
基金This project is jointly supported by the National Natural Science Foundation of China (No. 29871005) the Science Foundation of Austria (No. P12962-CHE).
文摘The thermodynamic factor in diffusion in the L1_2-type non-stoichiometricintermetallic compounds Ni_3Ga and Pt_3In was derived from the experimentally measured activities ofGa and In, respectively. The results show that the thermodynamic factor in diffusion in the Ni_3Gaand Pt_3In compounds exhibits the maximum near the stoichiometric composition with the variation ofcomposition over the compound region. The values indicate strong interaction between Ni and Gaatoms, as well as Pt and In atoms, respectively, as expected in ordered alloys.
文摘The present paper describes the energy analysis of a regenerative vapour power system. The regenerative steam turbines based on the Rankine cycle and comprised of vapour extractions have been used industrially since the beginning of the 20th century, particularly regarding the processes of electrical production. After having performed worked in the first stages of the turbine, part of the vapour is directed toward a regenerative exchanger and heats feedwater coming from the condenser. This process is known as regeneration, and the heat exchanger where the heat is transferred from steam is called a regenerator (or a feedwater heater). The profit in the output brought by regenerative rakings is primarily enabled by the lack of exchange of the tapped vapour reheating water with the low-temperature reservoir. The economic optimum is often fixed at seven extractions. One knows the Carnot relation, which is the best possible theoretical yield of a dual-temperature cycle;in a Carnot cycle, one makes the assumption that both compressions and expansions are isentropic. This article studies an ideal theoretical machine comprised of vapour extractions in which each cycle partial of tapped vapour obeys these same compressions and isentropic expansions.
基金This work was supported by the Department of Science and Technology,New Delhi(Project No.DST PROJECTSB/S2/LOP-032/2013)as well as School of Physical Sciences,SRTM University,Nanded,India for providing necessary facilities。
文摘The Complex permittivity spectra of glycol ether(GE)compounds such as ethylene glycol mono-methyl ether(EGME)with water mixture over entire concentration range and in temperature range of 10-25℃ have been determined using Time Domain Reflectometry(TDR)technique in the frequency range 10MHz to 50 GHz.The complex permittivity spectra for EGME-water were fitted in the Cole-Davidson model.The Static dielectric constant(ε_(0)^(E)),Relaxation time(τ),effective Kirkwood correlation factor(g_(eff)),excess permittivity(ε_(0)),thermodynamic parameters(activation enthalpy and activation entropy)and Bruggeman factor(f_(B))have been calculated by the nonlinear least square fit method.The intermolecular interactions between EGME-water binary mixtures suggest the nonlinear behavior of dielectric parameters.The contribution of hydrogen bonding interactions among the solute-solvent mixtures is confirmed by Excess properties and Bruggeman factor.
