The quantization thermal excitation isotherms based on the maximum triad spin number (G) of each energy level for metal cluster were derived as a function of temperature by expanding the binomial theorems according to...The quantization thermal excitation isotherms based on the maximum triad spin number (G) of each energy level for metal cluster were derived as a function of temperature by expanding the binomial theorems according to energy levels. From them the quantized geometric mean heat capacity equations are expressed in sequence. Among them the five quantized geometric heat capacity equations, fit the best to the experimental heat capacity data of metal atoms at constant pressure. In the derivations we assume that the triad spin composed of an electron, its proton and its neutron in a metal cluster become a basic unit of thermal excitation. Boltzmann constant (kB) is found to be an average specific heat of an energy level in a metal cluster. And then the constant (kK) is found to be an average specific heat of a photon in a metal cluster. The core triad spin made of free neutrons may exist as the second one additional energy level. The energy levels are grouped according to the forms of four spins throughout two axes. Planck constant is theoretically obtained with the ratio of the internal energy of metal (U) to total isotherm number (N) through Equipartition theorem.展开更多
Constant-volume heat capacities of supercritical (SC) CO2, SC CO2-n-pentane, and SC CO2-n-heptane mixtures were determined at 308.15 K in the pressure range from 6 to 12 MPa. It was found that there is a maximum in ea...Constant-volume heat capacities of supercritical (SC) CO2, SC CO2-n-pentane, and SC CO2-n-heptane mixtures were determined at 308.15 K in the pressure range from 6 to 12 MPa. It was found that there is a maximum in each heat capacity vs pressure curve. Intermolecular interaction in the fluids was studied.展开更多
This paper stuides the elastic constants and some thermodynamic properties of Mg2SixSn1-x （x = 0, 0.25, 0.5, 0.75, 1） compounds by first-principles total energy calculations using the pseudo-potential plane-waves ap...This paper stuides the elastic constants and some thermodynamic properties of Mg2SixSn1-x （x = 0, 0.25, 0.5, 0.75, 1） compounds by first-principles total energy calculations using the pseudo-potential plane-waves approach based on density functional theory, within the generalized gradient approximation for the exchange and correlation potential. The elastic constants of Mg2SixSn1-x were calculated. It shows that, at 273 K, the elastic constants of Mg2Si and Mg2Sn are well consistent with previous experimental data. The isotropy decreases with increasing Sn content. The dependences of the elastic constants, the bulk modulus, the shear modulus and the Debye temperatures of Mg2Si and Mg2Si0.5Sn0.5 on pressure were discussed. Through the quasi-harmonic Debye model, in which phononic effects were considered, the specific heat capacities of Mg2SixSn1-x at constant volume and constant pressure were calculated. The calculated specific heat capacities are well consistent with the previous experimental data.展开更多
The thermodynamic properties of xanthone（XTH） and 135 polybrominated xanthones（PBXTHs） in the standard state have been calculated at the B3LYP/6-31G＊ level using Gaussian 03 program.The isodesmic reactions were d...The thermodynamic properties of xanthone（XTH） and 135 polybrominated xanthones（PBXTHs） in the standard state have been calculated at the B3LYP/6-31G＊ level using Gaussian 03 program.The isodesmic reactions were designed to calculate the standard enthalpy of formation（△fHθ） and standard free energy of formation（△fGθ） of PBXTH congeners.The relations of these thermodynamic parameters with the number and position of Br atom substitution（NPBS） were discussed,and it was found that there exist high correlation between thermodynamic parameters（entropy（Sθ）,△fHθ and △fGθ） and NPBS.According to the relative magnitude of their △fGθ,the relative stability order of PBXTH congeners was theoretically proposed.The relative rate constants of formation reactions of PBXTH congeners were calculated,Moreover,the values of molar heat capacity at constant pressure（Cp,m） from 200 to 1000 K for PBXTH congeners were also calculated,and the temperature dependence relation of them was obtained,suggesting very good relationships between Cp,m and temperature（T,T^1 and T^2） for almost all PBXTH congeners.展开更多
A new insight into the constant current-constant voltage （CC-CV） charge protocol based on the spherical diffusion model was presented. From the model, the CV-charge process compensates, to a large extent, the capaci...A new insight into the constant current-constant voltage （CC-CV） charge protocol based on the spherical diffusion model was presented. From the model, the CV-charge process compensates, to a large extent, the capacity loss in the CC process, and the capacity loss increases with increasing the charging rate and decreases with increasing the lithium-ion diffusion coefficient and using a smaller r value （smaller particle-size and larger diffusion coefficient） and a lower charge rate will be helpful to decreasing the capacity loss. The results show that the CC and the CV charging processes, in some way, are complementary and the capacity loss during the CC charging process due to the large electrochemical polarization can be effectively compensated from the CV charging process.展开更多
With the B3LYP calculation method of density functional theory（DFT）and the 6-31G＊ basis set,full optimization calculation was made for phenoxathiin10-oxide（PTO）and 135 polybromine phenoxathiin 10-oxides（PBPTOs）...With the B3LYP calculation method of density functional theory（DFT）and the 6-31G＊ basis set,full optimization calculation was made for phenoxathiin10-oxide（PTO）and 135 polybromine phenoxathiin 10-oxides（PBPTOs）with the Gaussian 03 program and molar heat capacity in constant volume（CVθ）value of each molecule in the standard state was obtained.The relation between CVθ and the substitution position and number of bromine atom（NPBS）was studied,and the results indicated good correlation（R2 = 1.000）between CVθ and NPBS of PBPTO compounds.Based on the output file of Gaussian 03 program,molar heat capacity at constant pressure（Cp,m）of PBPTO compounds from 200 to 1,000 K was calculated with the statistical thermodynamics program,and the correlation equation between Cp,m and temperature（T,T-1 and T-2）was obtained with the least-squares method,and the correlation coefficient of the correlation equation（R2）was 1.000.In addition,based on the partition function of each molecule calculated by vibration analysis,the relative rate constant of formation of each molecule was calculated.展开更多
In this paper, we propose an entanglement scheme for long-distance, constant-fidelity communication in quantum networks. We discuss the optimal rate of entanglement that allows for constant fidelity in both elementary...In this paper, we propose an entanglement scheme for long-distance, constant-fidelity communication in quantum networks. We discuss the optimal rate of entanglement that allows for constant fidelity in both elementary and muhihop links. We also discuss time complexity and propose the mathematical order of the rate capacity for an entanglement scheme. We propose a recursive entanglement scheme, a simultaneous entanglement scheme, and an adjacent entanglement scheme mathematically analyze these schemes. The rate capacity of the recursive and simultaneous entanglement schemes is Ω（1/e^n）, but the adjacent entanglement scheme performs better, providing a rate of lΩ（1/n）.展开更多
This paper reports that low-temperature heat capacities of N-methylnorephedrine C11H17NO（s） have been measured by a precision automated adiabatic calorimeter over the temperature range from T=78K to T=400K. A solid ...This paper reports that low-temperature heat capacities of N-methylnorephedrine C11H17NO（s） have been measured by a precision automated adiabatic calorimeter over the temperature range from T=78K to T=400K. A solid to liquid phase transition of the compound was found in the heat capacity curve in the temperature range of T=342-364 K. The peak temperature, molar enthalpy and entropy of fusion of the substance were determined. The experimental values of the molar heat capacities in the temperature regions of T=78-342 K and T=364-400 K were fitted to two poly- nomial equations of heat capacities with the reduced temperatures by least squares method. The smoothed molar heat capacities and thermodynamic functions of N-methylnorephedrine C11H17NO（s） relative to the standard refer- ence temperature 298.15 K were calculated based on the fitted polynomials and tabulated with an interval of 5 K. The constant-volume energy of combustion of the compound at T=298.15 K was measured by means of an isoperibol precision oxygen-bomb combustion calorimeter. The standard molar enthalpy of combustion of the sample was calculated. The standard molar enthalpy of formation of the compound was determined from the combustion enthalpy and other auxiliary thermodynamic data through a Hess thermochemical cycle.展开更多
文摘The quantization thermal excitation isotherms based on the maximum triad spin number (G) of each energy level for metal cluster were derived as a function of temperature by expanding the binomial theorems according to energy levels. From them the quantized geometric mean heat capacity equations are expressed in sequence. Among them the five quantized geometric heat capacity equations, fit the best to the experimental heat capacity data of metal atoms at constant pressure. In the derivations we assume that the triad spin composed of an electron, its proton and its neutron in a metal cluster become a basic unit of thermal excitation. Boltzmann constant (kB) is found to be an average specific heat of an energy level in a metal cluster. And then the constant (kK) is found to be an average specific heat of a photon in a metal cluster. The core triad spin made of free neutrons may exist as the second one additional energy level. The energy levels are grouped according to the forms of four spins throughout two axes. Planck constant is theoretically obtained with the ratio of the internal energy of metal (U) to total isotherm number (N) through Equipartition theorem.
文摘Constant-volume heat capacities of supercritical (SC) CO2, SC CO2-n-pentane, and SC CO2-n-heptane mixtures were determined at 308.15 K in the pressure range from 6 to 12 MPa. It was found that there is a maximum in each heat capacity vs pressure curve. Intermolecular interaction in the fluids was studied.
基金supported by the National Natural Science Foundation of China(Grant No 50504002)China Postdoctoral Science Foundation(Grant No 20060390030)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,China
文摘This paper stuides the elastic constants and some thermodynamic properties of Mg2SixSn1-x （x = 0, 0.25, 0.5, 0.75, 1） compounds by first-principles total energy calculations using the pseudo-potential plane-waves approach based on density functional theory, within the generalized gradient approximation for the exchange and correlation potential. The elastic constants of Mg2SixSn1-x were calculated. It shows that, at 273 K, the elastic constants of Mg2Si and Mg2Sn are well consistent with previous experimental data. The isotropy decreases with increasing Sn content. The dependences of the elastic constants, the bulk modulus, the shear modulus and the Debye temperatures of Mg2Si and Mg2Si0.5Sn0.5 on pressure were discussed. Through the quasi-harmonic Debye model, in which phononic effects were considered, the specific heat capacities of Mg2SixSn1-x at constant volume and constant pressure were calculated. The calculated specific heat capacities are well consistent with the previous experimental data.
基金Supported by the NNSFC (20737001, 20977046)NSF of Zhejiang Province (2008Y507280)
文摘The thermodynamic properties of xanthone（XTH） and 135 polybrominated xanthones（PBXTHs） in the standard state have been calculated at the B3LYP/6-31G＊ level using Gaussian 03 program.The isodesmic reactions were designed to calculate the standard enthalpy of formation（△fHθ） and standard free energy of formation（△fGθ） of PBXTH congeners.The relations of these thermodynamic parameters with the number and position of Br atom substitution（NPBS） were discussed,and it was found that there exist high correlation between thermodynamic parameters（entropy（Sθ）,△fHθ and △fGθ） and NPBS.According to the relative magnitude of their △fGθ,the relative stability order of PBXTH congeners was theoretically proposed.The relative rate constants of formation reactions of PBXTH congeners were calculated,Moreover,the values of molar heat capacity at constant pressure（Cp,m） from 200 to 1000 K for PBXTH congeners were also calculated,and the temperature dependence relation of them was obtained,suggesting very good relationships between Cp,m and temperature（T,T^1 and T^2） for almost all PBXTH congeners.
基金Projects(20676152, 20876178) supported by the National Natural Science Foundation of China
文摘A new insight into the constant current-constant voltage （CC-CV） charge protocol based on the spherical diffusion model was presented. From the model, the CV-charge process compensates, to a large extent, the capacity loss in the CC process, and the capacity loss increases with increasing the charging rate and decreases with increasing the lithium-ion diffusion coefficient and using a smaller r value （smaller particle-size and larger diffusion coefficient） and a lower charge rate will be helpful to decreasing the capacity loss. The results show that the CC and the CV charging processes, in some way, are complementary and the capacity loss during the CC charging process due to the large electrochemical polarization can be effectively compensated from the CV charging process.
基金supported by the National Natural Science Foundation of China (41071319,20977046 and 20737001)
文摘With the B3LYP calculation method of density functional theory（DFT）and the 6-31G＊ basis set,full optimization calculation was made for phenoxathiin10-oxide（PTO）and 135 polybromine phenoxathiin 10-oxides（PBPTOs）with the Gaussian 03 program and molar heat capacity in constant volume（CVθ）value of each molecule in the standard state was obtained.The relation between CVθ and the substitution position and number of bromine atom（NPBS）was studied,and the results indicated good correlation（R2 = 1.000）between CVθ and NPBS of PBPTO compounds.Based on the output file of Gaussian 03 program,molar heat capacity at constant pressure（Cp,m）of PBPTO compounds from 200 to 1,000 K was calculated with the statistical thermodynamics program,and the correlation equation between Cp,m and temperature（T,T-1 and T-2）was obtained with the least-squares method,and the correlation coefficient of the correlation equation（R2）was 1.000.In addition,based on the partition function of each molecule calculated by vibration analysis,the relative rate constant of formation of each molecule was calculated.
文摘In this paper, we propose an entanglement scheme for long-distance, constant-fidelity communication in quantum networks. We discuss the optimal rate of entanglement that allows for constant fidelity in both elementary and muhihop links. We also discuss time complexity and propose the mathematical order of the rate capacity for an entanglement scheme. We propose a recursive entanglement scheme, a simultaneous entanglement scheme, and an adjacent entanglement scheme mathematically analyze these schemes. The rate capacity of the recursive and simultaneous entanglement schemes is Ω（1/e^n）, but the adjacent entanglement scheme performs better, providing a rate of lΩ（1/n）.
基金Project supported by the National Natural Science Foundation of China （Grant No 20673050）.
文摘This paper reports that low-temperature heat capacities of N-methylnorephedrine C11H17NO（s） have been measured by a precision automated adiabatic calorimeter over the temperature range from T=78K to T=400K. A solid to liquid phase transition of the compound was found in the heat capacity curve in the temperature range of T=342-364 K. The peak temperature, molar enthalpy and entropy of fusion of the substance were determined. The experimental values of the molar heat capacities in the temperature regions of T=78-342 K and T=364-400 K were fitted to two poly- nomial equations of heat capacities with the reduced temperatures by least squares method. The smoothed molar heat capacities and thermodynamic functions of N-methylnorephedrine C11H17NO（s） relative to the standard refer- ence temperature 298.15 K were calculated based on the fitted polynomials and tabulated with an interval of 5 K. The constant-volume energy of combustion of the compound at T=298.15 K was measured by means of an isoperibol precision oxygen-bomb combustion calorimeter. The standard molar enthalpy of combustion of the sample was calculated. The standard molar enthalpy of formation of the compound was determined from the combustion enthalpy and other auxiliary thermodynamic data through a Hess thermochemical cycle.
