This paper reports that 1-dodecylamine hydrobromide (1 C12H25NH3.Br)(s) has been synthesized using the liquid phase reaction method. The lattice potential energy of the compound 1-C12H25NH3.Br and the ionic vol- u...This paper reports that 1-dodecylamine hydrobromide (1 C12H25NH3.Br)(s) has been synthesized using the liquid phase reaction method. The lattice potential energy of the compound 1-C12H25NH3.Br and the ionic vol- ume and radius of the 1-C12H25NH3+ cation are obtained from the crystallographic data and other auxiliary ther- modynamic data. The constant-volume energy of combustion of 1 C12H25NH3.Br(s) is measured to be AcUo(1 C12H25NH3.Br, s) = (7369.03-4-3.28) kJ.mo1-1 by means of an RBC-II precision rotating-bomb combustion calorime- ter at T=(298.15~0.001) K. The standard molar enthalpy of combustion of the compound is derived to be △cHo(1- C12H25NH3.Br, s)=- (7384.52±3.28) kJ.mo1-1 from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound is calculated to be △fHo(1-C12H25NH3.Br, s)=-(1317.86~3.67) kJ.mo1-1 from the standard molar enthalpy of combustion of the title compound and other auxiliary thermodynamic quantities through a thermochemical cycle.展开更多
The integral heat of solution of REBr 3·3Gly·3H 2O(RE=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Y; Gly is glycine) in water, REBr 3· n H 2O(RE=La, Ce and Pr, n =7; RE=Nd, Sm, Eu, Gd, Tb, Dy and Y, n...The integral heat of solution of REBr 3·3Gly·3H 2O(RE=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Y; Gly is glycine) in water, REBr 3· n H 2O(RE=La, Ce and Pr, n =7; RE=Nd, Sm, Eu, Gd, Tb, Dy and Y, n =6) in aqueous glycine solution and glycine in water have been measured calorimetrically at 298 15±0 15 K. By means of a thermochemical cycle suggested in this paper, the standard molar enthalpies of formation of REBr 3·3Gly·3H 2O have been obtained and their lattice energies have been calculated.展开更多
Some thermodynamic parnmeters of Pd-In alloys with 2 to 70 at. H indium have been determined in the temperuture range 800 to 1000℃ from e.m.f measurements ongalvanic cells with an onsen-cotzducting solid electrolyte....Some thermodynamic parnmeters of Pd-In alloys with 2 to 70 at. H indium have been determined in the temperuture range 800 to 1000℃ from e.m.f measurements ongalvanic cells with an onsen-cotzducting solid electrolyte. Heats of tnising calculated hem the activities are in excellent agreement with calorimetric data. The relative partial excess hee enengy of indiurn assumes unnsually larpe negative values ap to-174kJ/mol for Pd-rich alloys. Two efficts are discussed to account for the non-idealproperties: The rise Of Fermi enerpy as the valence electron8 of indium enter the 4dand 5sP bands of the alloy and the lattice distortion brought about by the differentmolar volumes of the cofnponents. The rise of the Fermi enerpy, as determlned fromthe activity data, indicates a strict adherence of the alloys to the rigid band model.展开更多
Titanomagnetite concentrate is one of the important titanium resources.The apparent activation energy(Ea)of the direct reduction of titanomagnetite concentrate was composed of two parts(average activation energy:E_(a)...Titanomagnetite concentrate is one of the important titanium resources.The apparent activation energy(Ea)of the direct reduction of titanomagnetite concentrate was composed of two parts(average activation energy:E_(a)=E_(a-L)+E_(a-Step1),where E_(a-L) is the lattice energy of titanomagnetite concentrate,and is the activation energy of step 1 for the reduction of titanomagnetite concentrate in the route of.Fe^(3+)→^(Step1)Fe^(2+)→^(Step2)Fe_(2)O^(2)→^(Step3)Fe^(0)).Ea(583.43 kJ/mol),(426.4 kJ/mol),and(157.0 kJ/mol)were calculated by the model-free methods based on thermogravimetry and Dmol3 module.Combined with the analysis of activation energy fluctuation and the shifting trend of related mechanism functions,the reduction kinetic system with three main characteristics,namely nucleation,diffusion and concentration fluctuation,was established.In addition,the scanning electron microscopy comparison analysis of the samples from microwave reduction and conventional reduction shows that microwave heating could realize the microstructure Ti-Fe separation and reduce the lattice energy of the titanomagnetite concentrate,thus enhancing the reduction process by 7.68%from the perspective of activation energy.展开更多
Ba_(1-x)Sr_(x)CuSi_(2)O_(6) compounds with a tetrahedral structure(I41/acd)were prepared through the solid-state reaction method.The phase building process,structural evolution and microwave dielectric properties of B...Ba_(1-x)Sr_(x)CuSi_(2)O_(6) compounds with a tetrahedral structure(I41/acd)were prepared through the solid-state reaction method.The phase building process,structural evolution and microwave dielectric properties of Ba_(1-x)Sr_(x)CuSi_(2)O_(6) were investigated.Single BaCuSi_(2)O_(6) phase can be obtained when calcined at 1050℃ for 3 h or 950℃ for 10 h.The substitution of Ba^(2+) by Sr^(2+) can effectively promote the sintering process and the maximum solubility of Ba_(1-x)Sr_(x)CuSi_(2)O_(6) was located between 0.25 and 0.30.Rietveld refinement,Raman-spectra and P-V-L complex chemical bond theory were used to explain the correlations between the crystal structures and microwave dielectric properties.The dielectric constant was dominated by the susceptibility(Σχ^(μ))and ionic polarizability.The quality factor(Q×f)was determined by the bond strength,packing fraction and lattice energy,especially the Si-O bond.The susceptibility of Cu-O bond and Si-O bond played an important role in controlling the temperature coefficient of the resonant frequency(τf).A near zero τf value was obtained at x=0-0.10 and the optimum microwave dielectric properties for Ba_(1-x)Sr_(x)CuSi_(2)O_(6) were achieved at x=0.20 when sintered at 1000℃ for 3 h:ε_(r)=8.25,Q×f=47616 GHz and τf=9.6 ppm/℃.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 20673050 and 20973089)
文摘This paper reports that 1-dodecylamine hydrobromide (1 C12H25NH3.Br)(s) has been synthesized using the liquid phase reaction method. The lattice potential energy of the compound 1-C12H25NH3.Br and the ionic vol- ume and radius of the 1-C12H25NH3+ cation are obtained from the crystallographic data and other auxiliary ther- modynamic data. The constant-volume energy of combustion of 1 C12H25NH3.Br(s) is measured to be AcUo(1 C12H25NH3.Br, s) = (7369.03-4-3.28) kJ.mo1-1 by means of an RBC-II precision rotating-bomb combustion calorime- ter at T=(298.15~0.001) K. The standard molar enthalpy of combustion of the compound is derived to be △cHo(1- C12H25NH3.Br, s)=- (7384.52±3.28) kJ.mo1-1 from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound is calculated to be △fHo(1-C12H25NH3.Br, s)=-(1317.86~3.67) kJ.mo1-1 from the standard molar enthalpy of combustion of the title compound and other auxiliary thermodynamic quantities through a thermochemical cycle.
文摘The integral heat of solution of REBr 3·3Gly·3H 2O(RE=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Y; Gly is glycine) in water, REBr 3· n H 2O(RE=La, Ce and Pr, n =7; RE=Nd, Sm, Eu, Gd, Tb, Dy and Y, n =6) in aqueous glycine solution and glycine in water have been measured calorimetrically at 298 15±0 15 K. By means of a thermochemical cycle suggested in this paper, the standard molar enthalpies of formation of REBr 3·3Gly·3H 2O have been obtained and their lattice energies have been calculated.
文摘Some thermodynamic parnmeters of Pd-In alloys with 2 to 70 at. H indium have been determined in the temperuture range 800 to 1000℃ from e.m.f measurements ongalvanic cells with an onsen-cotzducting solid electrolyte. Heats of tnising calculated hem the activities are in excellent agreement with calorimetric data. The relative partial excess hee enengy of indiurn assumes unnsually larpe negative values ap to-174kJ/mol for Pd-rich alloys. Two efficts are discussed to account for the non-idealproperties: The rise Of Fermi enerpy as the valence electron8 of indium enter the 4dand 5sP bands of the alloy and the lattice distortion brought about by the differentmolar volumes of the cofnponents. The rise of the Fermi enerpy, as determlned fromthe activity data, indicates a strict adherence of the alloys to the rigid band model.
基金National Key Research and Development Program of China(2018YFC1900500)Yunnan Province Special Key Project of Basic Research(202101as070014)Scientific Research Fund of Panzhihua University(XJ2022001301).
文摘Titanomagnetite concentrate is one of the important titanium resources.The apparent activation energy(Ea)of the direct reduction of titanomagnetite concentrate was composed of two parts(average activation energy:E_(a)=E_(a-L)+E_(a-Step1),where E_(a-L) is the lattice energy of titanomagnetite concentrate,and is the activation energy of step 1 for the reduction of titanomagnetite concentrate in the route of.Fe^(3+)→^(Step1)Fe^(2+)→^(Step2)Fe_(2)O^(2)→^(Step3)Fe^(0)).Ea(583.43 kJ/mol),(426.4 kJ/mol),and(157.0 kJ/mol)were calculated by the model-free methods based on thermogravimetry and Dmol3 module.Combined with the analysis of activation energy fluctuation and the shifting trend of related mechanism functions,the reduction kinetic system with three main characteristics,namely nucleation,diffusion and concentration fluctuation,was established.In addition,the scanning electron microscopy comparison analysis of the samples from microwave reduction and conventional reduction shows that microwave heating could realize the microstructure Ti-Fe separation and reduce the lattice energy of the titanomagnetite concentrate,thus enhancing the reduction process by 7.68%from the perspective of activation energy.
基金supported by the National Natural Science Foundation of China(NSFC-51572093,51772107 and 61771215)Research Project of Electronic Components and Devices of China(1807WM0004)the Major Programs of Technical Innovation in Hubei Province of China(2018AAA039).
文摘Ba_(1-x)Sr_(x)CuSi_(2)O_(6) compounds with a tetrahedral structure(I41/acd)were prepared through the solid-state reaction method.The phase building process,structural evolution and microwave dielectric properties of Ba_(1-x)Sr_(x)CuSi_(2)O_(6) were investigated.Single BaCuSi_(2)O_(6) phase can be obtained when calcined at 1050℃ for 3 h or 950℃ for 10 h.The substitution of Ba^(2+) by Sr^(2+) can effectively promote the sintering process and the maximum solubility of Ba_(1-x)Sr_(x)CuSi_(2)O_(6) was located between 0.25 and 0.30.Rietveld refinement,Raman-spectra and P-V-L complex chemical bond theory were used to explain the correlations between the crystal structures and microwave dielectric properties.The dielectric constant was dominated by the susceptibility(Σχ^(μ))and ionic polarizability.The quality factor(Q×f)was determined by the bond strength,packing fraction and lattice energy,especially the Si-O bond.The susceptibility of Cu-O bond and Si-O bond played an important role in controlling the temperature coefficient of the resonant frequency(τf).A near zero τf value was obtained at x=0-0.10 and the optimum microwave dielectric properties for Ba_(1-x)Sr_(x)CuSi_(2)O_(6) were achieved at x=0.20 when sintered at 1000℃ for 3 h:ε_(r)=8.25,Q×f=47616 GHz and τf=9.6 ppm/℃.