A new estimation method was proposed by combining the corresponding state principle with the group contribution method through introducing the concept of assumed-critical properties. Combining it with the Reidel equat...A new estimation method was proposed by combining the corresponding state principle with the group contribution method through introducing the concept of assumed-critical properties. Combining it with the Reidel equation, a new acentric factor correlation equation (CSGC-Reidel) was developed. Contribution values of 70 groups were obtained by correlating acentric factor data of 228 organic compounds of 14 type substances including saturated hydrocarbons, unsaturated hydrocarbons, cyclanes, aromatics, oxygen compounds, nitrogen compounds,halohydrocarbons, etc. The average error of acentric factor is 3.52% between the literature data and the predicated with the new estimation method.展开更多
Herein,two new acentric borogermanates,namely,Ca_(2)GeB_(2)O_(7) and Ca_(1.78)Cd_(0.22)GeB_(2)O_(7),were obtained by combining BO4 with a GeO4 tetrahedron.The structures of the isomeric Ca_(2)GeB_(2)O_(7) and Ca_(1.78...Herein,two new acentric borogermanates,namely,Ca_(2)GeB_(2)O_(7) and Ca_(1.78)Cd_(0.22)GeB_(2)O_(7),were obtained by combining BO4 with a GeO4 tetrahedron.The structures of the isomeric Ca_(2)GeB_(2)O_(7) and Ca_(1.78)Cd_(0.22)GeB_(2)O_(7) feature two-dimensional(2D)[GeB2O7]layers parallel to the ab plane in which a GeO4 tetrahedron corner is shared with four[B2O7]units;the divalent cations are filled in between layers.Ca_(2)GeB_(2)O_(7) and Ca_(1.78)Cd_(0.22)GeB_(2)O_(7) display second-harmonic generation(SHG)intensity around 0.4 and 0.6 times that of KH2PO4(KDP),respectively.Ca_(2)GeB_(2)O_(7) possesses a short UV absorption edge(about 194 nm).Thermal stability measurements show that Ca_(2)GeB_(2)O_(7) melts congruently at high temperatures,whereas Ca_(1.78)Cd_(0.22)GeB_(2)O_(7) melts incongruently and becomes amorphous at high temperatures.Moreover,measurements of the optical properties as well as theoretical calculations of these two compounds were conducted.展开更多
In this paper, a scheme of spatial perturbation is introduced into a class of excitable media, which are described by two-dimensional partial-differential equation models. Inertial acentric force （or centrlpetal forc...In this paper, a scheme of spatial perturbation is introduced into a class of excitable media, which are described by two-dimensional partial-differential equation models. Inertial acentric force （or centrlpetal force）, which is generated by circumgyrating the whole system vs. a right axis, is used to disturb the system. The whole system becomes homogeneous as soon as the spatial perturbation is imposed on even when the noise is in consideration. The principle of this scheme is confirmed based on the theory of hopf bifurcation and numerical simulation.展开更多
A novel alpha function for Peng-Robinson equation of state was proposed and generalized with acentric factor and dipole moment for predicting thermodynamic properties of non-polar,weakly polar,and polar compounds.The ...A novel alpha function for Peng-Robinson equation of state was proposed and generalized with acentric factor and dipole moment for predicting thermodynamic properties of non-polar,weakly polar,and polar compounds.The parameters of new alpha function were fitted with vapor pressures of 70 compounds.Six different methods were investigated for the correlation of parameters of new alpha function and Heyen alpha function.The generalized new alpha function passed the consistency test.The results indicated that the predictive accuracy of generalized new alpha function and generalized Heyen alpha function was improved for the estimation of vapor pressure of 11 kinds of compounds,with the average relative deviations(ARDs)being 2.60%and 2.76%.The ARDs of the two generalized alpha functions were 2.04%and 2.09%for the enthalpy of vaporization.However,the generalized new alpha function and the other alpha functions had great deviations for the prediction of liquid volumes and isobaric heat capacities.The alpha function that was generalized with acentric factor and reduced dipole moment was more accurate than that was generalized with acentric factor,especially for the prediction of vapor pressure and enthalpy of vaporization of polar compounds.展开更多
A series of new acentric fluoroborophosphates,namely,RbBPO_(4)F,CsBPO_(4)F and(NH_(4))_(2)BPO_(4)F_(2),have been obtained by combining BO_(3)F or BO_(2)F_(2)with a PO_(4)tetrahedron.The structures of the isomeric RbBP...A series of new acentric fluoroborophosphates,namely,RbBPO_(4)F,CsBPO_(4)F and(NH_(4))_(2)BPO_(4)F_(2),have been obtained by combining BO_(3)F or BO_(2)F_(2)with a PO_(4)tetrahedron.The structures of the isomeric RbBPO_(4)F and CsBPO_(4)F feature a three-dimensional diamond framework,in which a BO_(3)F(or PO_(4))tetrahedron corner is shared with three PO_(4)(or BO_(3)F)tetrahedra,forming 1D tunnels of eight-membered rings(MRs)along the three axial directions,which are filled with alkali cations.(NH_(4))_(2)BPO_(4)F_(2)exhibits a 3D supramolecular structure,in which 1D[BPO_(4)F_(2)]^(1-)anionic chains along the a axes based on cornersharing and alternating PO_(4)and BO_(2)F_(2)tetrahedra are further interconnected with ammonium cations by electrostatic attractions and hydrogen bonds.RbBPO_(4)F,CsBPO_(4)F and(NH_(4))_(2)BPO_(4)F_(2)display second-harmonic generation(SHG)signals approximately 0.4,0.6 and 0.8 times that of KH_(2)PO_(4)(KDP)and exhibit short UV absorption edges(<200 nm).Measurements of thermal stability and optical properties and theoretical calculations have also been performed.展开更多
La_(4)Ge_(3)S_(12)was structurally characterized in 1974 without any optical or nonlinear optical properties reported.Herein we report that the acentric crystal structure of La_(4)Ge_(3)S_(12)has been confirmed by sin...La_(4)Ge_(3)S_(12)was structurally characterized in 1974 without any optical or nonlinear optical properties reported.Herein we report that the acentric crystal structure of La_(4)Ge_(3)S_(12)has been confirmed by singlecrystal X-ray diffraction.The nonlinear optical properties test revealed its phase-matchable behavior with a good balance between the second harmonic generation(SHG)response and laser damage threshold(LDT).Theory calculations predicted that the optical properties of La_(4)Ge_(3)S_(12)are dominantly contributed by sulfur atoms.Band gap engineering was applied to tune the optical properties of La_(4)Ge_(3)S_(12)by replacing S with Se,which resulted in five new compounds:La_(4)Ge_(3)Se_(2)S_(10),La_(4)Ge_(3)Se_(4)S_(8),La_(4)Ge_(3)Se_(6)S_(6),La_(4)Ge_(3)Se_(8)S_(4),and La_(4)Ge3Se10S2.High quality mm-sized crystals of La_(4)Ge_(3)Se_(x)S_(12−x)(x=0,2,4,6,8,10)were grown by a hightemperature vapor transport reaction followed by salt flux growth methods.All La_(4)Ge_(3)Se_(x)S_(12−x)(x=0,2,4,6,8,10)compounds are isostructural and crystallize in the noncentrosymmetric rhombohedral space group R3c(no.161)with unit cell volumes of 2639.2Å^(3),2698.6Å^(3),2745.3Å^(3),2792.6Å^(3),2845.3Å^(3),and 2912.1Å^(3),for x=0,2,4,6,8,and 10,respectively.La_(4)Ge_(3)S_(12)shows a band gap of 3.1(1)eV,and the incorporation of Se to the system suppresses the band gap of the compound La_(4)Ge_(3)Se_(10)S_(2) to 1.9(1)eV.The incorporation of Se significantly shifts the nonlinear optical properties of La_(4)Ge_(3)S_(12),with an example of the SHG response of La_(4)Ge_(3)Se_(4)S_(8)being four times higher than La_(4)Ge_(3)S_(12).The optical and nonlinear optical properties of La_(4)Ge_(3)Se_(x)S_(12−x)(x=0,2,4,6,8,10)compounds are reported.展开更多
文摘A new estimation method was proposed by combining the corresponding state principle with the group contribution method through introducing the concept of assumed-critical properties. Combining it with the Reidel equation, a new acentric factor correlation equation (CSGC-Reidel) was developed. Contribution values of 70 groups were obtained by correlating acentric factor data of 228 organic compounds of 14 type substances including saturated hydrocarbons, unsaturated hydrocarbons, cyclanes, aromatics, oxygen compounds, nitrogen compounds,halohydrocarbons, etc. The average error of acentric factor is 3.52% between the literature data and the predicated with the new estimation method.
基金supported by the National Natural Science Foundation of China(No.21875248,91622112,and 21701173)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000)the 100 Talents Project of Fujian Province.
文摘Herein,two new acentric borogermanates,namely,Ca_(2)GeB_(2)O_(7) and Ca_(1.78)Cd_(0.22)GeB_(2)O_(7),were obtained by combining BO4 with a GeO4 tetrahedron.The structures of the isomeric Ca_(2)GeB_(2)O_(7) and Ca_(1.78)Cd_(0.22)GeB_(2)O_(7) feature two-dimensional(2D)[GeB2O7]layers parallel to the ab plane in which a GeO4 tetrahedron corner is shared with four[B2O7]units;the divalent cations are filled in between layers.Ca_(2)GeB_(2)O_(7) and Ca_(1.78)Cd_(0.22)GeB_(2)O_(7) display second-harmonic generation(SHG)intensity around 0.4 and 0.6 times that of KH2PO4(KDP),respectively.Ca_(2)GeB_(2)O_(7) possesses a short UV absorption edge(about 194 nm).Thermal stability measurements show that Ca_(2)GeB_(2)O_(7) melts congruently at high temperatures,whereas Ca_(1.78)Cd_(0.22)GeB_(2)O_(7) melts incongruently and becomes amorphous at high temperatures.Moreover,measurements of the optical properties as well as theoretical calculations of these two compounds were conducted.
基金The project supported partially by National Natural Science Foundation of China under Grant Nos. 90303010, 1052056 and Natural Science Foundation of Gansu Province of China under Grant No. 3ZS042-B25-021 We would like to thank Profs. H. Zhang and H.P. Ying for valuable discussions
文摘In this paper, a scheme of spatial perturbation is introduced into a class of excitable media, which are described by two-dimensional partial-differential equation models. Inertial acentric force （or centrlpetal force）, which is generated by circumgyrating the whole system vs. a right axis, is used to disturb the system. The whole system becomes homogeneous as soon as the spatial perturbation is imposed on even when the noise is in consideration. The principle of this scheme is confirmed based on the theory of hopf bifurcation and numerical simulation.
基金supported by National Natural Science Foundation of China(22008129,22108138)。
文摘A novel alpha function for Peng-Robinson equation of state was proposed and generalized with acentric factor and dipole moment for predicting thermodynamic properties of non-polar,weakly polar,and polar compounds.The parameters of new alpha function were fitted with vapor pressures of 70 compounds.Six different methods were investigated for the correlation of parameters of new alpha function and Heyen alpha function.The generalized new alpha function passed the consistency test.The results indicated that the predictive accuracy of generalized new alpha function and generalized Heyen alpha function was improved for the estimation of vapor pressure of 11 kinds of compounds,with the average relative deviations(ARDs)being 2.60%and 2.76%.The ARDs of the two generalized alpha functions were 2.04%and 2.09%for the enthalpy of vaporization.However,the generalized new alpha function and the other alpha functions had great deviations for the prediction of liquid volumes and isobaric heat capacities.The alpha function that was generalized with acentric factor and reduced dipole moment was more accurate than that was generalized with acentric factor,especially for the prediction of vapor pressure and enthalpy of vaporization of polar compounds.
基金National Natural Science Foundation of China(No.21875248,91622112,and 21701173)Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000)100 Talents Project of Fujian Province。
文摘A series of new acentric fluoroborophosphates,namely,RbBPO_(4)F,CsBPO_(4)F and(NH_(4))_(2)BPO_(4)F_(2),have been obtained by combining BO_(3)F or BO_(2)F_(2)with a PO_(4)tetrahedron.The structures of the isomeric RbBPO_(4)F and CsBPO_(4)F feature a three-dimensional diamond framework,in which a BO_(3)F(or PO_(4))tetrahedron corner is shared with three PO_(4)(or BO_(3)F)tetrahedra,forming 1D tunnels of eight-membered rings(MRs)along the three axial directions,which are filled with alkali cations.(NH_(4))_(2)BPO_(4)F_(2)exhibits a 3D supramolecular structure,in which 1D[BPO_(4)F_(2)]^(1-)anionic chains along the a axes based on cornersharing and alternating PO_(4)and BO_(2)F_(2)tetrahedra are further interconnected with ammonium cations by electrostatic attractions and hydrogen bonds.RbBPO_(4)F,CsBPO_(4)F and(NH_(4))_(2)BPO_(4)F_(2)display second-harmonic generation(SHG)signals approximately 0.4,0.6 and 0.8 times that of KH_(2)PO_(4)(KDP)and exhibit short UV absorption edges(<200 nm).Measurements of thermal stability and optical properties and theoretical calculations have also been performed.
基金supported by start-up funds from Wichita State University.
文摘La_(4)Ge_(3)S_(12)was structurally characterized in 1974 without any optical or nonlinear optical properties reported.Herein we report that the acentric crystal structure of La_(4)Ge_(3)S_(12)has been confirmed by singlecrystal X-ray diffraction.The nonlinear optical properties test revealed its phase-matchable behavior with a good balance between the second harmonic generation(SHG)response and laser damage threshold(LDT).Theory calculations predicted that the optical properties of La_(4)Ge_(3)S_(12)are dominantly contributed by sulfur atoms.Band gap engineering was applied to tune the optical properties of La_(4)Ge_(3)S_(12)by replacing S with Se,which resulted in five new compounds:La_(4)Ge_(3)Se_(2)S_(10),La_(4)Ge_(3)Se_(4)S_(8),La_(4)Ge_(3)Se_(6)S_(6),La_(4)Ge_(3)Se_(8)S_(4),and La_(4)Ge3Se10S2.High quality mm-sized crystals of La_(4)Ge_(3)Se_(x)S_(12−x)(x=0,2,4,6,8,10)were grown by a hightemperature vapor transport reaction followed by salt flux growth methods.All La_(4)Ge_(3)Se_(x)S_(12−x)(x=0,2,4,6,8,10)compounds are isostructural and crystallize in the noncentrosymmetric rhombohedral space group R3c(no.161)with unit cell volumes of 2639.2Å^(3),2698.6Å^(3),2745.3Å^(3),2792.6Å^(3),2845.3Å^(3),and 2912.1Å^(3),for x=0,2,4,6,8,and 10,respectively.La_(4)Ge_(3)S_(12)shows a band gap of 3.1(1)eV,and the incorporation of Se to the system suppresses the band gap of the compound La_(4)Ge_(3)Se_(10)S_(2) to 1.9(1)eV.The incorporation of Se significantly shifts the nonlinear optical properties of La_(4)Ge_(3)S_(12),with an example of the SHG response of La_(4)Ge_(3)Se_(4)S_(8)being four times higher than La_(4)Ge_(3)S_(12).The optical and nonlinear optical properties of La_(4)Ge_(3)Se_(x)S_(12−x)(x=0,2,4,6,8,10)compounds are reported.
