Three-dimensional thermal a nalysis simulation of a horizontal zone refining system is conducted for germanimn semiconductor materials. The considered geometry includes a g＇ral）hite boat filled with germanium placed...Three-dimensional thermal a nalysis simulation of a horizontal zone refining system is conducted for germanimn semiconductor materials. The considered geometry includes a g＇ral）hite boat filled with germanium placed in a cylindrical quartz tube. A flow of Ar and H2 gas mixture is purged througll the tube. A narrow section of the, boat is assmned to be exposed to a constant heat rate produced b v an rf coil located outside the quartz tube. The results of this analysis provide essential information about various parameters such as the shape of tile molten zone, required power and temperature gradient in the system.展开更多
Based on the density functional theory, the influences of strain on structural, elastic, thermal and optical properties of CuGaTe2 are discussed in detail. It is found that the tensile strain on CuGaTe2 is beneficial ...Based on the density functional theory, the influences of strain on structural, elastic, thermal and optical properties of CuGaTe2 are discussed in detail. It is found that the tensile strain on CuGaTe2 is beneficial to the decrease of lattice thermal conductivity by reducing the mean sound velocity and Debye temperature. Moreover, all strained and unstrained CuGaTe2 exhibit rather similar optical characters. But the tensile strain improves the ability to absorb sunlight in the visible range.These research findings can give hints for designing thermoelectric and photovoltaic devices.展开更多
A high-degree (degree l = 6 and order m = 0, 1, 2, [midline ellipsis] , l. High-order model for short) and steady thermal free convective motion of an infinite Prandtl number and Boussinesq fluid in a spherical shell ...A high-degree (degree l = 6 and order m = 0, 1, 2, [midline ellipsis] , l. High-order model for short) and steady thermal free convective motion of an infinite Prandtl number and Boussinesq fluid in a spherical shell is calculated by a Galerkin method. Convection is driven by an imposed temperature drop across top rigid and bottom stress-free isothermal boundaries only heated from below of the shell. In this paper, the scalar poloidal and fluctuating temperature fields are expanded into associated Legendre polynomials with degree l = 6 and order m = 0, 1, 2, [midline ellipsis] , l. Compared with zero-order model (degree l = 6 and order m = 0), from which 2-D longitudinal (r-θ) profiles can be obtained, high-order model can provide a series of southerly (r-θ), easterly (r-φ) and radial (θ-φ) velocity profiles, which probably reveal more detail features of mass motion in the mantle. It is found that Rayleigh number has great effects on the patterns and velocities of thermal free convection and controls the relative ratio of hot and cold plume in the shell. Probably, the present results mainly reveal the mass motion in the lower mantle, while the striking differences of convection patterns from velocities at different positions have important geodynamical significances.展开更多
We improved the thermal equivalent-circuit model of the laser diode module（LDM） to evaluate its thermal dynamic properties and calculate the junction temperature of the laser diode with a high accuracy.The thermal p...We improved the thermal equivalent-circuit model of the laser diode module（LDM） to evaluate its thermal dynamic properties and calculate the junction temperature of the laser diode with a high accuracy.The thermal parameters and the transient junction temperature of the LDM are modeled and obtained according to the temperature of the thermistor integrated in the module.Our improved thermal model is verified indirectly by monitoring the emission wavelength of the laser diode against gas absorption lines,and several thermal parameters are obtained with the temperature uncertainty of 0.01 K in the thermal dynamic process.展开更多
The high temperature gas occurs behind shock or near the wall surface of vehicle in the hypersonic flight. As the temperature exceeds 2 000 K, 4 000 K, respectively, O2 and N2 molecules are successively dissociated. B...The high temperature gas occurs behind shock or near the wall surface of vehicle in the hypersonic flight. As the temperature exceeds 2 000 K, 4 000 K, respectively, O2 and N2 molecules are successively dissociated. Because of variable components at dif- ferent temperatures and pressures, the dissociated air is no longer a perfect gas, In this paper, a new method is developed to calculate accurate thermal physical parameters with the dissociation degree providing the thermochemical equilibrium procedure. Based on the dissociation degree, it is concluded that few numbers of equations and the solutions are easily obtained. In addition, a set of formulas relating the parameter to the dissociation degree are set up four-species, O2 molecule The thermodynamic properties of dissociated air containing and N2 molecule, O atom and N atom, are studied with the new method, and the results are consistent with those with the traditional equilibrium constant method. It is shown that this method is reliable for solving thermal physical parameters easily and directly.展开更多
Coal fly ash is being utilized as a recycling material for catalysis due to its aluminosilicate content. Catalytic conversion of polymeric wastes into synthetic gasoline and diesel through pyrolysis requires applicati...Coal fly ash is being utilized as a recycling material for catalysis due to its aluminosilicate content. Catalytic conversion of polymeric wastes into synthetic gasoline and diesel through pyrolysis requires application of kinetic and thermodynamic principles. This study aimed to identify the catalytic rate constant necessary for rate law involved in reaction mechanisms and activation energy reduction needed for heat transfer rate. Stoichiometric application for balanced total series of elementary reactions is solved for the concentration determination of reactants and products. Unsteady-state in three dimensional directions of thermodynamics is derived for the determination of heat transfer rate, temperatures at any position in a sphere using Gurney and Lurie chart and center temperature in a sphere by Heisler chart. Application principles of rate law and Arrhenius equation can result to thermal conductivity as a function of activation energy leading to synthetic fuel production.展开更多
文摘Three-dimensional thermal a nalysis simulation of a horizontal zone refining system is conducted for germanimn semiconductor materials. The considered geometry includes a g＇ral）hite boat filled with germanium placed in a cylindrical quartz tube. A flow of Ar and H2 gas mixture is purged througll the tube. A narrow section of the, boat is assmned to be exposed to a constant heat rate produced b v an rf coil located outside the quartz tube. The results of this analysis provide essential information about various parameters such as the shape of tile molten zone, required power and temperature gradient in the system.
基金supported by the National Natural Science Foundation of China(Grant No.11304105)
文摘Based on the density functional theory, the influences of strain on structural, elastic, thermal and optical properties of CuGaTe2 are discussed in detail. It is found that the tensile strain on CuGaTe2 is beneficial to the decrease of lattice thermal conductivity by reducing the mean sound velocity and Debye temperature. Moreover, all strained and unstrained CuGaTe2 exhibit rather similar optical characters. But the tensile strain improves the ability to absorb sunlight in the visible range.These research findings can give hints for designing thermoelectric and photovoltaic devices.
基金National Natural Science Foundation of China (49834020).
文摘A high-degree (degree l = 6 and order m = 0, 1, 2, [midline ellipsis] , l. High-order model for short) and steady thermal free convective motion of an infinite Prandtl number and Boussinesq fluid in a spherical shell is calculated by a Galerkin method. Convection is driven by an imposed temperature drop across top rigid and bottom stress-free isothermal boundaries only heated from below of the shell. In this paper, the scalar poloidal and fluctuating temperature fields are expanded into associated Legendre polynomials with degree l = 6 and order m = 0, 1, 2, [midline ellipsis] , l. Compared with zero-order model (degree l = 6 and order m = 0), from which 2-D longitudinal (r-θ) profiles can be obtained, high-order model can provide a series of southerly (r-θ), easterly (r-φ) and radial (θ-φ) velocity profiles, which probably reveal more detail features of mass motion in the mantle. It is found that Rayleigh number has great effects on the patterns and velocities of thermal free convection and controls the relative ratio of hot and cold plume in the shell. Probably, the present results mainly reveal the mass motion in the lower mantle, while the striking differences of convection patterns from velocities at different positions have important geodynamical significances.
基金Project supported by the Key Program of the National Natural Science Foundation of China (Grant No. 60938002)the Special-funded Program on National Key Scientific Instruments and Equipment Development of China (Grant No. 2012YQ06016501)the Tianjin Research Program of Application Foundation and Advanced Technology,China (Grant No. 11JCYBJC04900)
文摘We improved the thermal equivalent-circuit model of the laser diode module（LDM） to evaluate its thermal dynamic properties and calculate the junction temperature of the laser diode with a high accuracy.The thermal parameters and the transient junction temperature of the LDM are modeled and obtained according to the temperature of the thermistor integrated in the module.Our improved thermal model is verified indirectly by monitoring the emission wavelength of the laser diode against gas absorption lines,and several thermal parameters are obtained with the temperature uncertainty of 0.01 K in the thermal dynamic process.
基金supported by the National Natural Science Foundation of China(Nos.11732011,11672205,and 11332007)the National Key Research and Development Program of China(No.2016YFA0401200)
文摘The high temperature gas occurs behind shock or near the wall surface of vehicle in the hypersonic flight. As the temperature exceeds 2 000 K, 4 000 K, respectively, O2 and N2 molecules are successively dissociated. Because of variable components at dif- ferent temperatures and pressures, the dissociated air is no longer a perfect gas, In this paper, a new method is developed to calculate accurate thermal physical parameters with the dissociation degree providing the thermochemical equilibrium procedure. Based on the dissociation degree, it is concluded that few numbers of equations and the solutions are easily obtained. In addition, a set of formulas relating the parameter to the dissociation degree are set up four-species, O2 molecule The thermodynamic properties of dissociated air containing and N2 molecule, O atom and N atom, are studied with the new method, and the results are consistent with those with the traditional equilibrium constant method. It is shown that this method is reliable for solving thermal physical parameters easily and directly.
文摘Coal fly ash is being utilized as a recycling material for catalysis due to its aluminosilicate content. Catalytic conversion of polymeric wastes into synthetic gasoline and diesel through pyrolysis requires application of kinetic and thermodynamic principles. This study aimed to identify the catalytic rate constant necessary for rate law involved in reaction mechanisms and activation energy reduction needed for heat transfer rate. Stoichiometric application for balanced total series of elementary reactions is solved for the concentration determination of reactants and products. Unsteady-state in three dimensional directions of thermodynamics is derived for the determination of heat transfer rate, temperatures at any position in a sphere using Gurney and Lurie chart and center temperature in a sphere by Heisler chart. Application principles of rate law and Arrhenius equation can result to thermal conductivity as a function of activation energy leading to synthetic fuel production.
