Low-temperature heat capacities of the solid compound Zn（C4H7O5）2（s） were measured in a temperature range from 78 to 374 K, with an automated adiabatic calorimeter. A solid-to-solid phase transition occurred in th...Low-temperature heat capacities of the solid compound Zn（C4H7O5）2（s） were measured in a temperature range from 78 to 374 K, with an automated adiabatic calorimeter. A solid-to-solid phase transition occurred in the temperature range of 295？322 K. The peak temperature, the enthalpy, and entropy of the phase transition were determined to be （316.269±1.039） K, （11.194±0.335） kJ？mol-1, and （35.391±0.654） J？K-1？mol-1, respectively. The experimental values of the molar heat capacities in the temperature regions of 78？295 K and 322？374 K were fitted to two polynomial equations of heat capacities（Cp,m） with reduced temperatures（X） and [X = f（T）], with the help of the least squares method, respectively. The smoothed molar heat capacities and thermodynamic functions of the compound, relative to that of the standard reference temperature 293.15 K, were calculated on the basis of the fitted polynomials and tabulated with an interval of 5 K. In addition, the possible mechanism of thermal decomposition of the compound was inferred by the result of TG-DTG analysis.展开更多
The heat capacities of D-galactose and galactitol were measured on a quantum design physical property measurement system（PPMS） over a temperature range of 1.9-300 K, and the experimental data were fitted to a functi...The heat capacities of D-galactose and galactitol were measured on a quantum design physical property measurement system（PPMS） over a temperature range of 1.9-300 K, and the experimental data were fitted to a function of T using a series of theoretical and empirical models in appropriate temperature ranges. The fit results were used to calculate thermodynamic function values, C^θp,m, ^T0S0^θm , and △^T0H^θm from 0 K to 300 K. The standard molar heat capacity, entropy and enthalpy values of D-galactose and galactitol at 298.15 K and 0.1 MPa were determined to be C^θp,m=（227.96±2.28） and（239.50±2.40） J·K^-1·mol^-1, S0^θm = （211.22±2.11） and （230.82±2.30） J·K^-1·mol^-1 and μm = （33.95±0.34） and （36.57±0.37） kJ/mol, respectively.展开更多
Low temperature calorimetry is an experimental method of heat capacity measurements, and heatcapacity is one of the most important and fundamental thermodynamic properties of substances. Theheat capacity can provide a...Low temperature calorimetry is an experimental method of heat capacity measurements, and heatcapacity is one of the most important and fundamental thermodynamic properties of substances. Theheat capacity can provide an average evaluation of the thermal property of a sample since it is a bull（property of substances. In the other hand, the condensed states of substances could be mainly controlledby the molecular motions, intermolecular interactions, and interplay among molecular structures. Thephysical property reflected in a material may be closely related to the energy changes in these threefactors, which can be directly observed in a heat capacity curve. Therefore, low temperature calorimetryhas been used not only to obtain heat capacity, entropy, enthalpy and Gibbs free energy, but also toinvestigate and understand lattice vibrations, metals, superconductivity, electronic and nuclearmagnetism, dilute magnetic systems and structural transitions. In this review, we have presented theconcept of low temperature calorimetry and its applications in the related field of material researches,such as nano-materials, magnetic materials, ferroelectric materials, phase change materials and othermaterials.展开更多
基金the National Natural Science Foundation of China(No.20673050).
文摘Low-temperature heat capacities of the solid compound Zn（C4H7O5）2（s） were measured in a temperature range from 78 to 374 K, with an automated adiabatic calorimeter. A solid-to-solid phase transition occurred in the temperature range of 295？322 K. The peak temperature, the enthalpy, and entropy of the phase transition were determined to be （316.269±1.039） K, （11.194±0.335） kJ？mol-1, and （35.391±0.654） J？K-1？mol-1, respectively. The experimental values of the molar heat capacities in the temperature regions of 78？295 K and 322？374 K were fitted to two polynomial equations of heat capacities（Cp,m） with reduced temperatures（X） and [X = f（T）], with the help of the least squares method, respectively. The smoothed molar heat capacities and thermodynamic functions of the compound, relative to that of the standard reference temperature 293.15 K, were calculated on the basis of the fitted polynomials and tabulated with an interval of 5 K. In addition, the possible mechanism of thermal decomposition of the compound was inferred by the result of TG-DTG analysis.
基金Supported by the National Natural Science Foundation of China（No.21473198）.
文摘The heat capacities of D-galactose and galactitol were measured on a quantum design physical property measurement system（PPMS） over a temperature range of 1.9-300 K, and the experimental data were fitted to a function of T using a series of theoretical and empirical models in appropriate temperature ranges. The fit results were used to calculate thermodynamic function values, C^θp,m, ^T0S0^θm , and △^T0H^θm from 0 K to 300 K. The standard molar heat capacity, entropy and enthalpy values of D-galactose and galactitol at 298.15 K and 0.1 MPa were determined to be C^θp,m=（227.96±2.28） and（239.50±2.40） J·K^-1·mol^-1, S0^θm = （211.22±2.11） and （230.82±2.30） J·K^-1·mol^-1 and μm = （33.95±0.34） and （36.57±0.37） kJ/mol, respectively.
基金Project supported by the National Natural Science Foundation of China （No. 20673050）, the Poat-doctor Start-up Foundation of Liaocheng Univer sity （No. 31805）.
基金financially supported by the National Natural Science Foundation of China(Nos.21473198,11775226)Natural Science Foundation of Liaoning Provincial(No.201602741)Hundred-Talent Program founded by Chinese Academy of Sciences
文摘Low temperature calorimetry is an experimental method of heat capacity measurements, and heatcapacity is one of the most important and fundamental thermodynamic properties of substances. Theheat capacity can provide an average evaluation of the thermal property of a sample since it is a bull（property of substances. In the other hand, the condensed states of substances could be mainly controlledby the molecular motions, intermolecular interactions, and interplay among molecular structures. Thephysical property reflected in a material may be closely related to the energy changes in these threefactors, which can be directly observed in a heat capacity curve. Therefore, low temperature calorimetryhas been used not only to obtain heat capacity, entropy, enthalpy and Gibbs free energy, but also toinvestigate and understand lattice vibrations, metals, superconductivity, electronic and nuclearmagnetism, dilute magnetic systems and structural transitions. In this review, we have presented theconcept of low temperature calorimetry and its applications in the related field of material researches,such as nano-materials, magnetic materials, ferroelectric materials, phase change materials and othermaterials.
