This paper, an addendum to “Dialectical Thermodynamics’ solution to the conceptual imbroglio that is the reversible path”, this journal, 10, 775-799, was written in response to the requests of several readers to pr...This paper, an addendum to “Dialectical Thermodynamics’ solution to the conceptual imbroglio that is the reversible path”, this journal, 10, 775-799, was written in response to the requests of several readers to provide further evidence of the said “imbroglio”. The evidence here presented relates to the incompatibility existing between the total-entropy and the Gibbs energy prescriptions for the reversible path. The previously published proof of the negentropic nature of the transformation of heat into work is here included to validate out conclusions about the Gibbs energy perspective.展开更多
The direct conversion of greenhouse gas CO_(2) and low-cost CH3OH into valuable dimethyl carbonate(DMC)offers a promising low-carbon synthetic pathway,but the slow CO_(2) activation kinetics and entropy-decreasing nat...The direct conversion of greenhouse gas CO_(2) and low-cost CH3OH into valuable dimethyl carbonate(DMC)offers a promising low-carbon synthetic pathway,but the slow CO_(2) activation kinetics and entropy-decreasing nature of this reaction significantly restrict DMC yield to below 1%.In this work,2-cyanopyridine(2-CP)was employed as a dehydrating agent to suppress the reverse reaction between DMC and H_(2)O,shifting the thermodynamic equilibrium in favor of DMC production.Under this thermodynamic unconstrained condition,increasing oxygen vacancies,especially in the form of oxygen vacancy clusters,promotes catalytic activity significantly.We achieve a catalytic activity of 211 mmol/(g·h)at 140℃ on H_(2)-treated,oxygen-vacancy-clusters-rich CeO_(2) in the presence of 2-CP,a 1.6-fold increase compared to the activity with air-treated CeO_(2) under identical conditions.The DMC yield reaches 8.54%in a 20mL CH3OH solution with 2-CP,surpassing the calculated DMC yield of about 0.66%from the reaction equilibrium constant under the same conditions and without using the dehydrating agent.This work suggests the importance of using a dehydrating agent and also highlights oxygen vacancy clusters as pivotal active sites to promote DMC synthesis.Achieving sustainable DMC synthesis requires further exploration,encompassing strategies such as methods for regeneration of 2-CP.展开更多
In this paper,a new efficient,and at the same time,very simple and general class of thermodynamically compatiblefinite volume schemes is introduced for the discretization of nonlinear,overdetermined,and thermodynamicall...In this paper,a new efficient,and at the same time,very simple and general class of thermodynamically compatiblefinite volume schemes is introduced for the discretization of nonlinear,overdetermined,and thermodynamically compatiblefirst-order hyperbolic systems.By construction,the proposed semi-discrete method satisfies an entropy inequality and is nonlinearly stable in the energy norm.A very peculiar feature of our approach is that entropy is discretized directly,while total energy conservation is achieved as a mere consequence of the thermodynamically compatible discretization.The new schemes can be applied to a very general class of nonlinear systems of hyperbolic PDEs,including both,conservative and non-conservative products,as well as potentially stiff algebraic relaxation source terms,provided that the underlying system is overdetermined and therefore satisfies an additional extra conservation law,such as the conservation of total energy density.The proposed family offinite volume schemes is based on the seminal work of Abgrall[1],where for thefirst time a completely general methodology for the design of thermodynamically compatible numerical methods for overdetermined hyperbolic PDE was presented.We apply our new approach to three particular thermodynamically compatible systems:the equations of ideal magnetohydrodynamics(MHD)with thermodynamically compatible generalized Lagrangian multiplier(GLM)divergence cleaning,the unifiedfirst-order hyperbolic model of continuum mechanics proposed by Godunov,Peshkov,and Romenski(GPR model)and thefirst-order hyperbolic model for turbulent shallow waterflows of Gavrilyuk et al.In addition to formal mathematical proofs of the properties of our newfinite volume schemes,we also present a large set of numerical results in order to show their potential,efficiency,and practical applicability.展开更多
Structural and lattice dynamical properties of ReB2,RuB2,and OsB2 in the ReB2 structure are studied in the framework of density functional theory within the generalized gradient approximation.The present results show ...Structural and lattice dynamical properties of ReB2,RuB2,and OsB2 in the ReB2 structure are studied in the framework of density functional theory within the generalized gradient approximation.The present results show that these compounds are dynamically stable for the considered structure.The temperature-dependent behaviors of thermodynamical properties such as internal energy,free energy,entropy,and heat capacity are also presented.The obtained results are in good agreement with the available experimental and theoretical data.展开更多
Based on the detailed configuration accounting (DCA) model, a method is developed to include the resonant photoionization and the excitation-autoionization in the non-local thermodynamical equilibrium (NLTE) average a...Based on the detailed configuration accounting (DCA) model, a method is developed to include the resonant photoionization and the excitation-autoionization in the non-local thermodynamical equilibrium (NLTE) average atom (AA) model. Using this new model, the mean charge states and the opacity are calculated for NLTE high- plasmas and compared with other results. The agreement with AA model is poor at low electron density. The present results agree well with those of DCA model within 10%. The calculations show that the NLTE effects on opacity are strong.展开更多
Analytical expressions for the thermodynamical properties of a two-dimensional electron gas in a perpendicular mag- netic field are derived. This is accomplished by first deriving the general expression for the thermo...Analytical expressions for the thermodynamical properties of a two-dimensional electron gas in a perpendicular mag- netic field are derived. This is accomplished by first deriving the general expression for the thermodynamical potential, and then employing this result to obtain the corresponding expression for the two-dimensional gas. The chemical potential and magnetization are studied as a function of temperature and magnetic field, and shown to be in agreement with prior work. It is also shown that the results are close to those obtained by assuming a Gaussian density of states for the Landau levels.展开更多
The entropy density, energy density, pressure and equation of state around the RNAdS black hole are calculated in the WKB approximation on the Teukolsky-type master equation. The appearance of spin-dependent terms is ...The entropy density, energy density, pressure and equation of state around the RNAdS black hole are calculated in the WKB approximation on the Teukolsky-type master equation. The appearance of spin-dependent terms is demonstrated. The existence of these terms shows that the black hole radiation is not exactly thermal radiation and the black hole entropy is not strictly proportional to the area of the event horizon.展开更多
We present a thermodynamically consistent model for diblock copolymer melts coupled with an electric field derived using the Onsager linear response theory.We compare the model with the thermodynamically inconsistent ...We present a thermodynamically consistent model for diblock copolymer melts coupled with an electric field derived using the Onsager linear response theory.We compare the model with the thermodynamically inconsistent one previously used for the coupled system to highlight their differences in describing transient dynamics.展开更多
The melting and freezing processes of CUN （N =180, 256, 360, 408, 500, 628 and 736） nanoclnsters are simulated by using micro-canonical molecular dynamics simulation technique, The potential energies and the heat ca...The melting and freezing processes of CUN （N =180, 256, 360, 408, 500, 628 and 736） nanoclnsters are simulated by using micro-canonical molecular dynamics simulation technique, The potential energies and the heat capacities as a function of temperature are obtained. The results reveal that the melting and freezing points increase almost linearly with the atom number in the cluster increasing. All copper nanoclusters have negative heat capacity around the melting and freezing points, and hysteresis effect in the melting/freezing transition is derived in CUN nanoclusters for the first time.展开更多
The free-cutting phase in RE or Ca-RE treated sulfur-containing free-cutting steel is the eutectic phases of MnS-RE_2S_3 and (Mn,Ca)S-RE_2S_3,respectively.The atomic ratio of RE/S needed to modify all the MnS into the...The free-cutting phase in RE or Ca-RE treated sulfur-containing free-cutting steel is the eutectic phases of MnS-RE_2S_3 and (Mn,Ca)S-RE_2S_3,respectively.The atomic ratio of RE/S needed to modify all the MnS into the eutectic phase is higher than 1.48 or 1.41-1.37 Ca/S,when RE or Ca-RE is used as the modifiz- er in the sulfur-containing free-cutting steel.Moreover,the thermodynamical calculation shows that the eutectic temperature is lower than the solidifying temperature,which is the key condition for the eutectic phase to keep globual during solidifying.展开更多
Complete optimization was conducted for 136 polybromo-phenoxathiin congeners（PBPTs） on the B3LYP/6-31G＊ level with Gaussian 03 program.The structural parameters and thermodynamical parameters of each molecule were ...Complete optimization was conducted for 136 polybromo-phenoxathiin congeners（PBPTs） on the B3LYP/6-31G＊ level with Gaussian 03 program.The structural parameters and thermodynamical parameters of each molecule were obtained under the standard state of 298.15 K and 1.013×10^5 Pa.Reverse linear regression was employed to establish the quantitative structure-property correlation models between heat capacity at constant volume（CVθ）,entropy（Sθ）,standard heat of formation（△fHθ） and standard free energy of formation（△fGθ） of PBPTs and the structural parameters（the most negative atomic charge（q^-） and molecular average polarizability（α））.These models presented better correlations（r^2〉0.97）.And they were validated by variance inflation factor（VIF） and t-test,which can better explain the regularity of thermodynamical property of PBPTs,and has good stability and great prediction ability.展开更多
This study demonstrates that our previously reported polywraplex, a synthetic siRNA carrier consisting of a uni-molecular polyplex core of customizable size and a self-assembled triblock copolymer envelop, may be cons...This study demonstrates that our previously reported polywraplex, a synthetic siRNA carrier consisting of a uni-molecular polyplex core of customizable size and a self-assembled triblock copolymer envelop, may be constructed using dendrimers as the crosslinking junctions. Replacing the branched low molecular weight PEI with polyamidoamine(PAMAM) dendrimer in the zeta potential regulated polymerization resulted in the similar network structured cationic polymer with electron microscopically visible crosslinking junctions. This visibility may offer a convenient way to characterize the molecular structure of the rationally designed networked siRNA-packing cationic polymer without altering its chemical properties and biologic functions. A series of physical-chemical characterizations and biological assays, comprising size, zeta potential, pre-phagocytic siRNA leaking and degradation, and silencing of functional genes, confirmed that the advanced properties of polywraplexes remained with the dendrimer junctions. Although sixth generation PAMAM dendrimer was used as the crosslinking junctions in the size-customizable polymerization for electron microscopic observation, lower generation dendrimer should also work in case more practical and structurally defined cationic polymer is needed.展开更多
In this paper, the discussion is made on the problem of the oceanic response caused by air-sea interaction under storm. First, the perturbation differential equations for the problem are given, and the interaction fun...In this paper, the discussion is made on the problem of the oceanic response caused by air-sea interaction under storm. First, the perturbation differential equations for the problem are given, and the interaction functions are supposed to be the solving conditions. Next, the nonlinear diffusion equations of the problem are solved by using the method of the given variable transforms and the specific variable power series. Finally, the response disturbances to the circular intense storm is calculated so as to discribe quantitatively the evolution processes of the oceanic response.展开更多
The present research work examines extraction mechanism of zinc by D2 EHPA(Di-2-ethyl hexyl phosphoric acid) and comprehensively studies the main effective parameters on the process. Results of thermodynamic experimen...The present research work examines extraction mechanism of zinc by D2 EHPA(Di-2-ethyl hexyl phosphoric acid) and comprehensively studies the main effective parameters on the process. Results of thermodynamic experiments showed that zinc extraction by D2 EHPA was endothermic and spontaneous, and thermodynamic parameters including entropy and enthalpy were + 27.37 J·mol^(-1)·K^(-1) and 25.21 kJ·mol^(-1), respectively.Gibbs free energy was varied between-7.21 kJ·mol^(-1) and-8.41 kJ·mol^(-1) with the variation of temperature from 20 °C to 70 °C. Solution ionic strength was increased by addition of potassium and lithium sulfate solution while addition of calcium sulfate decreased ionic strength whereby zinc extraction efficiency was also decreased.TBP showed positive synergism at concentration of 5%(v/v) and negative synergism effect at concentrations of2% and 10%. Simultaneous addition of both TBP and salt caused extraction efficiency to drop significantly and lower both TBP and ionic strength efficiency. Results showed that a continuous addition of TBP tends to effectively improve the zinc extraction efficiency. Experiments in the presence of catalyst Ni-Raney demonstrated that zinc extraction kinetic increases remarkably and due to easy recycling of the catalyst, we can propose a novel idea in solvent extraction field.展开更多
We reconsider the study of critical behaviors of Kerr—Newman Anti-de Sitter(AdS)black holes in four dimensions.The study is made in terms of the moduli space parameterized by the charge Q and the rotation parameter a...We reconsider the study of critical behaviors of Kerr—Newman Anti-de Sitter(AdS)black holes in four dimensions.The study is made in terms of the moduli space parameterized by the charge Q and the rotation parameter a,relating the mass M of the black hole and its angular momentum J via the relation a=J/M.Specifically,we discuss such thermodynamical behaviors in the presence of a positive cosmological constant considered as a thermodynamic pressure and its conjugate quantity as a thermodynamic volume.The equation of state for a charged Reissner—Nordstrom AdS black hole predicts a critical universal number depending on the(Q,a)moduli space.In the vanishing limit of the a parameter,this prediction recovers the usual universal number in four dimensions.Then,we find the bounded region of the moduli space allowing the consistency of the model with real thermodynamical variables.展开更多
Inclusion of dissipation and memory mechanisms, non-classical elasticity and thermal effects in the currently used plate/shell mathematical models require that we establish if these mathematical models can be derived ...Inclusion of dissipation and memory mechanisms, non-classical elasticity and thermal effects in the currently used plate/shell mathematical models require that we establish if these mathematical models can be derived using the conservation and balance laws of continuum mechanics in conjunction with the corresponding kinematic assumptions. This is referred to as thermodynamic consistency of the mathematical models. Thermodynamic consistency ensures thermodynamic equilibrium during the evolution of the deformation. When the mathematical models are thermodynamically consistent, the second law of thermodynamics facilitates consistent derivations of constitutive theories in the presence of dissipation and memory mechanisms. This is the main motivation for the work presented in this paper. In the currently used mathematical models for plates/shells based on the assumed kinematic relations, energy functional is constructed over the volume consisting of kinetic energy, strain energy and the potential energy of the loads. The Euler’s equations derived from the first variation of the energy functional for arbitrary length when set to zero yield the mathematical model(s) for the deforming plates/shells. Alternatively, principle of virtual work can also be used to derive the same mathematical model(s). For linear elastic reversible deformation physics with small deformation and small strain, these two approaches, based on energy functional and the principle of virtual work, yield the same mathematical models. These mathematical models hold for reversible mechanical deformation. In this paper, we examine whether the currently used plate/shell mathematical models with the corresponding kinematic assumptions can be derived using the conservation and balance laws of classical or non-classical continuum mechanics. The mathematical models based on Kirchhoff hypothesis (classical plate theory, CPT) and first order shear deformation theory (FSDT) that are representative of most mathematical models for plates/shells are investigated in this paper for their thermodynamic consistency. This is followed by the details of a general and higher order thermodynamically consistent plate/shell thermoelastic mathematical model that is free of a priori consideration of kinematic assumptions and remains valid for very thin as well as thick plates/shells with comprehensive nonlinear constitutive theories based on integrity. Model problem studies are presented for small deformation behavior of linear elastic plates in the absence of thermal effects and the results are compared with CPT and FSDT mathematical models.展开更多
We investigate the unified first law and the generalized second law in a modified holographic dark energy model. The thermodynamical analysis on the apparent horizon can work and the corresponding entropy formula is e...We investigate the unified first law and the generalized second law in a modified holographic dark energy model. The thermodynamical analysis on the apparent horizon can work and the corresponding entropy formula is extracted from the systematic algorithm. The entropy correction term depends on the extra-dimension number of the brane as expected, but the interplay between the correction term and the extra dimensions is more complicated. With the unified first law of thermodynamics well-founded, the generalized second law of thermodynamics is discussed and it is found that the second law can be violated in certain circumstances. Particularly, if the number of the extra dimensions is larger than one, the generalized law of thermodynamics is always satisfied; otherwise, the validity of the second law can only be guaranteed with the Hubble radius greatly smaller than the crossover scale rcof the 5-dimensional DGP model.展开更多
Sialon ceramic materials and its main three preparation methods have been outlined, among which preparing sialon powder from Kaolin through the carbothermal reduction and nitridation process is an economical,simple an...Sialon ceramic materials and its main three preparation methods have been outlined, among which preparing sialon powder from Kaolin through the carbothermal reduction and nitridation process is an economical,simple and practical synthesis process.However,the reaction system is complex due to the fact that there exist a lot of influencing factors and several reactions are taking place simutaneously. Partial reactions related to the chemical reaction system of the carbothermal and nitridation process,sialon powder prepared from the purified Kaolin,are analyzed thermodynamically, the systhesis temperature of sialon powder is 1400℃.The theoretical bases used to find the rational process of production are provided.The results prove to be practical.展开更多
The thermodynamical properties of silver are calculated by using a recent model of many-body potential from lattice inversion method.The predictions of the phonon dispersion relation,the Grüneisen constant and th...The thermodynamical properties of silver are calculated by using a recent model of many-body potential from lattice inversion method.The predictions of the phonon dispersion relation,the Grüneisen constant and the linear thermal expansion coefficient are all in coincidence with experiments.Of more importance,the present approach represents an efficient way of building potential functions capable of depicting the thermodynamics of metals for the Finnis-Sinclair model.展开更多
Results of the experimental measurements on the partial molar volume of kerosene used as a medium for dissolving TBP are utilized to determine the activity of TBP in the binary kerosene-TBP solution through the applic...Results of the experimental measurements on the partial molar volume of kerosene used as a medium for dissolving TBP are utilized to determine the activity of TBP in the binary kerosene-TBP solution through the application of Gibbs-Duhem equation. The treatment is based on combination of the experimental data with the thermodynamic values available on the compressibility factor of pure kerosene at room temperature. It is shown that the activity of TBP in kerosene has a positive deviation from ideality with an activity coefficient derived as follows:1) at X TBP ≤ 0.01: γ TBP = 42.530, 2) at the 0.01 X TBP 0.2: 3) at the higher TBP concentrations 0.2 X TBP 0.97: and 4) at TBP Raoultian concentrations 0.97 ≤ X TBP:γ TBP = 1. These quantities can be utilized at temperature closed to 298 K.展开更多
文摘This paper, an addendum to “Dialectical Thermodynamics’ solution to the conceptual imbroglio that is the reversible path”, this journal, 10, 775-799, was written in response to the requests of several readers to provide further evidence of the said “imbroglio”. The evidence here presented relates to the incompatibility existing between the total-entropy and the Gibbs energy prescriptions for the reversible path. The previously published proof of the negentropic nature of the transformation of heat into work is here included to validate out conclusions about the Gibbs energy perspective.
基金supported by the National Natural Science Foundation of China(Nos.22272078 and 52371196)the National Key Research and Development Programof the Ministry of Science and Technology of China(No.2020YFA0406102)the“Innovation and Entrepreneurship of Talents plan”of Jiangsu Province.
文摘The direct conversion of greenhouse gas CO_(2) and low-cost CH3OH into valuable dimethyl carbonate(DMC)offers a promising low-carbon synthetic pathway,but the slow CO_(2) activation kinetics and entropy-decreasing nature of this reaction significantly restrict DMC yield to below 1%.In this work,2-cyanopyridine(2-CP)was employed as a dehydrating agent to suppress the reverse reaction between DMC and H_(2)O,shifting the thermodynamic equilibrium in favor of DMC production.Under this thermodynamic unconstrained condition,increasing oxygen vacancies,especially in the form of oxygen vacancy clusters,promotes catalytic activity significantly.We achieve a catalytic activity of 211 mmol/(g·h)at 140℃ on H_(2)-treated,oxygen-vacancy-clusters-rich CeO_(2) in the presence of 2-CP,a 1.6-fold increase compared to the activity with air-treated CeO_(2) under identical conditions.The DMC yield reaches 8.54%in a 20mL CH3OH solution with 2-CP,surpassing the calculated DMC yield of about 0.66%from the reaction equilibrium constant under the same conditions and without using the dehydrating agent.This work suggests the importance of using a dehydrating agent and also highlights oxygen vacancy clusters as pivotal active sites to promote DMC synthesis.Achieving sustainable DMC synthesis requires further exploration,encompassing strategies such as methods for regeneration of 2-CP.
文摘In this paper,a new efficient,and at the same time,very simple and general class of thermodynamically compatiblefinite volume schemes is introduced for the discretization of nonlinear,overdetermined,and thermodynamically compatiblefirst-order hyperbolic systems.By construction,the proposed semi-discrete method satisfies an entropy inequality and is nonlinearly stable in the energy norm.A very peculiar feature of our approach is that entropy is discretized directly,while total energy conservation is achieved as a mere consequence of the thermodynamically compatible discretization.The new schemes can be applied to a very general class of nonlinear systems of hyperbolic PDEs,including both,conservative and non-conservative products,as well as potentially stiff algebraic relaxation source terms,provided that the underlying system is overdetermined and therefore satisfies an additional extra conservation law,such as the conservation of total energy density.The proposed family offinite volume schemes is based on the seminal work of Abgrall[1],where for thefirst time a completely general methodology for the design of thermodynamically compatible numerical methods for overdetermined hyperbolic PDE was presented.We apply our new approach to three particular thermodynamically compatible systems:the equations of ideal magnetohydrodynamics(MHD)with thermodynamically compatible generalized Lagrangian multiplier(GLM)divergence cleaning,the unifiedfirst-order hyperbolic model of continuum mechanics proposed by Godunov,Peshkov,and Romenski(GPR model)and thefirst-order hyperbolic model for turbulent shallow waterflows of Gavrilyuk et al.In addition to formal mathematical proofs of the properties of our newfinite volume schemes,we also present a large set of numerical results in order to show their potential,efficiency,and practical applicability.
文摘Structural and lattice dynamical properties of ReB2,RuB2,and OsB2 in the ReB2 structure are studied in the framework of density functional theory within the generalized gradient approximation.The present results show that these compounds are dynamically stable for the considered structure.The temperature-dependent behaviors of thermodynamical properties such as internal energy,free energy,entropy,and heat capacity are also presented.The obtained results are in good agreement with the available experimental and theoretical data.
文摘Based on the detailed configuration accounting (DCA) model, a method is developed to include the resonant photoionization and the excitation-autoionization in the non-local thermodynamical equilibrium (NLTE) average atom (AA) model. Using this new model, the mean charge states and the opacity are calculated for NLTE high- plasmas and compared with other results. The agreement with AA model is poor at low electron density. The present results agree well with those of DCA model within 10%. The calculations show that the NLTE effects on opacity are strong.
基金Project supported by the National Natural Science Foundation of China(Grant No.11275100)the K.C.Wong Magna Foundation of Ningbo University,China
文摘Analytical expressions for the thermodynamical properties of a two-dimensional electron gas in a perpendicular mag- netic field are derived. This is accomplished by first deriving the general expression for the thermodynamical potential, and then employing this result to obtain the corresponding expression for the two-dimensional gas. The chemical potential and magnetization are studied as a function of temperature and magnetic field, and shown to be in agreement with prior work. It is also shown that the results are close to those obtained by assuming a Gaussian density of states for the Landau levels.
基金Project supported by the National Natural Science Foundation of China （Grant No 10375051）.
文摘The entropy density, energy density, pressure and equation of state around the RNAdS black hole are calculated in the WKB approximation on the Teukolsky-type master equation. The appearance of spin-dependent terms is demonstrated. The existence of these terms shows that the black hole radiation is not exactly thermal radiation and the black hole entropy is not strictly proportional to the area of the event horizon.
基金partially supported by the National Natural Science Foundation of China(Grant Nos.11971051 and U1930402)partially supported by National Science Foundation grants(award DMS-1815921,1954532 and OIA-1655740)a GEAR award from SC EPSCoR/IDeA Program。
文摘We present a thermodynamically consistent model for diblock copolymer melts coupled with an electric field derived using the Onsager linear response theory.We compare the model with the thermodynamically inconsistent one previously used for the coupled system to highlight their differences in describing transient dynamics.
文摘The melting and freezing processes of CUN （N =180, 256, 360, 408, 500, 628 and 736） nanoclnsters are simulated by using micro-canonical molecular dynamics simulation technique, The potential energies and the heat capacities as a function of temperature are obtained. The results reveal that the melting and freezing points increase almost linearly with the atom number in the cluster increasing. All copper nanoclusters have negative heat capacity around the melting and freezing points, and hysteresis effect in the melting/freezing transition is derived in CUN nanoclusters for the first time.
基金The project supported by the National Natural Science Foundation of China
文摘The free-cutting phase in RE or Ca-RE treated sulfur-containing free-cutting steel is the eutectic phases of MnS-RE_2S_3 and (Mn,Ca)S-RE_2S_3,respectively.The atomic ratio of RE/S needed to modify all the MnS into the eutectic phase is higher than 1.48 or 1.41-1.37 Ca/S,when RE or Ca-RE is used as the modifiz- er in the sulfur-containing free-cutting steel.Moreover,the thermodynamical calculation shows that the eutectic temperature is lower than the solidifying temperature,which is the key condition for the eutectic phase to keep globual during solidifying.
基金supported by the Scientific Research Foundation of Guangxi Provincial Education Department (GJKY (2006) No 26)the Research Funds of Guangxi Key Laboratory of Environmental Engineering, Protection and Assessment (0801K007, 0801K008)
文摘Complete optimization was conducted for 136 polybromo-phenoxathiin congeners（PBPTs） on the B3LYP/6-31G＊ level with Gaussian 03 program.The structural parameters and thermodynamical parameters of each molecule were obtained under the standard state of 298.15 K and 1.013×10^5 Pa.Reverse linear regression was employed to establish the quantitative structure-property correlation models between heat capacity at constant volume（CVθ）,entropy（Sθ）,standard heat of formation（△fHθ） and standard free energy of formation（△fGθ） of PBPTs and the structural parameters（the most negative atomic charge（q^-） and molecular average polarizability（α））.These models presented better correlations（r^2〉0.97）.And they were validated by variance inflation factor（VIF） and t-test,which can better explain the regularity of thermodynamical property of PBPTs,and has good stability and great prediction ability.
基金the grant of the Natural Science Foundation of China(Grant nos.81373352 and 81690262)。
文摘This study demonstrates that our previously reported polywraplex, a synthetic siRNA carrier consisting of a uni-molecular polyplex core of customizable size and a self-assembled triblock copolymer envelop, may be constructed using dendrimers as the crosslinking junctions. Replacing the branched low molecular weight PEI with polyamidoamine(PAMAM) dendrimer in the zeta potential regulated polymerization resulted in the similar network structured cationic polymer with electron microscopically visible crosslinking junctions. This visibility may offer a convenient way to characterize the molecular structure of the rationally designed networked siRNA-packing cationic polymer without altering its chemical properties and biologic functions. A series of physical-chemical characterizations and biological assays, comprising size, zeta potential, pre-phagocytic siRNA leaking and degradation, and silencing of functional genes, confirmed that the advanced properties of polywraplexes remained with the dendrimer junctions. Although sixth generation PAMAM dendrimer was used as the crosslinking junctions in the size-customizable polymerization for electron microscopic observation, lower generation dendrimer should also work in case more practical and structurally defined cationic polymer is needed.
文摘In this paper, the discussion is made on the problem of the oceanic response caused by air-sea interaction under storm. First, the perturbation differential equations for the problem are given, and the interaction functions are supposed to be the solving conditions. Next, the nonlinear diffusion equations of the problem are solved by using the method of the given variable transforms and the specific variable power series. Finally, the response disturbances to the circular intense storm is calculated so as to discribe quantitatively the evolution processes of the oceanic response.
文摘The present research work examines extraction mechanism of zinc by D2 EHPA(Di-2-ethyl hexyl phosphoric acid) and comprehensively studies the main effective parameters on the process. Results of thermodynamic experiments showed that zinc extraction by D2 EHPA was endothermic and spontaneous, and thermodynamic parameters including entropy and enthalpy were + 27.37 J·mol^(-1)·K^(-1) and 25.21 kJ·mol^(-1), respectively.Gibbs free energy was varied between-7.21 kJ·mol^(-1) and-8.41 kJ·mol^(-1) with the variation of temperature from 20 °C to 70 °C. Solution ionic strength was increased by addition of potassium and lithium sulfate solution while addition of calcium sulfate decreased ionic strength whereby zinc extraction efficiency was also decreased.TBP showed positive synergism at concentration of 5%(v/v) and negative synergism effect at concentrations of2% and 10%. Simultaneous addition of both TBP and salt caused extraction efficiency to drop significantly and lower both TBP and ionic strength efficiency. Results showed that a continuous addition of TBP tends to effectively improve the zinc extraction efficiency. Experiments in the presence of catalyst Ni-Raney demonstrated that zinc extraction kinetic increases remarkably and due to easy recycling of the catalyst, we can propose a novel idea in solvent extraction field.
文摘We reconsider the study of critical behaviors of Kerr—Newman Anti-de Sitter(AdS)black holes in four dimensions.The study is made in terms of the moduli space parameterized by the charge Q and the rotation parameter a,relating the mass M of the black hole and its angular momentum J via the relation a=J/M.Specifically,we discuss such thermodynamical behaviors in the presence of a positive cosmological constant considered as a thermodynamic pressure and its conjugate quantity as a thermodynamic volume.The equation of state for a charged Reissner—Nordstrom AdS black hole predicts a critical universal number depending on the(Q,a)moduli space.In the vanishing limit of the a parameter,this prediction recovers the usual universal number in four dimensions.Then,we find the bounded region of the moduli space allowing the consistency of the model with real thermodynamical variables.
文摘Inclusion of dissipation and memory mechanisms, non-classical elasticity and thermal effects in the currently used plate/shell mathematical models require that we establish if these mathematical models can be derived using the conservation and balance laws of continuum mechanics in conjunction with the corresponding kinematic assumptions. This is referred to as thermodynamic consistency of the mathematical models. Thermodynamic consistency ensures thermodynamic equilibrium during the evolution of the deformation. When the mathematical models are thermodynamically consistent, the second law of thermodynamics facilitates consistent derivations of constitutive theories in the presence of dissipation and memory mechanisms. This is the main motivation for the work presented in this paper. In the currently used mathematical models for plates/shells based on the assumed kinematic relations, energy functional is constructed over the volume consisting of kinetic energy, strain energy and the potential energy of the loads. The Euler’s equations derived from the first variation of the energy functional for arbitrary length when set to zero yield the mathematical model(s) for the deforming plates/shells. Alternatively, principle of virtual work can also be used to derive the same mathematical model(s). For linear elastic reversible deformation physics with small deformation and small strain, these two approaches, based on energy functional and the principle of virtual work, yield the same mathematical models. These mathematical models hold for reversible mechanical deformation. In this paper, we examine whether the currently used plate/shell mathematical models with the corresponding kinematic assumptions can be derived using the conservation and balance laws of classical or non-classical continuum mechanics. The mathematical models based on Kirchhoff hypothesis (classical plate theory, CPT) and first order shear deformation theory (FSDT) that are representative of most mathematical models for plates/shells are investigated in this paper for their thermodynamic consistency. This is followed by the details of a general and higher order thermodynamically consistent plate/shell thermoelastic mathematical model that is free of a priori consideration of kinematic assumptions and remains valid for very thin as well as thick plates/shells with comprehensive nonlinear constitutive theories based on integrity. Model problem studies are presented for small deformation behavior of linear elastic plates in the absence of thermal effects and the results are compared with CPT and FSDT mathematical models.
基金Supported by National Foundation of China under Grant Nos.10747155 and 11205131the Ministry of Science and Technology of the National Natural Science Foundation of China key project under Grant Nos.11175270,11005164,11073005,and 10935013Chongqing Science and Technology Commission under Grant No.2010BB0408
文摘We investigate the unified first law and the generalized second law in a modified holographic dark energy model. The thermodynamical analysis on the apparent horizon can work and the corresponding entropy formula is extracted from the systematic algorithm. The entropy correction term depends on the extra-dimension number of the brane as expected, but the interplay between the correction term and the extra dimensions is more complicated. With the unified first law of thermodynamics well-founded, the generalized second law of thermodynamics is discussed and it is found that the second law can be violated in certain circumstances. Particularly, if the number of the extra dimensions is larger than one, the generalized law of thermodynamics is always satisfied; otherwise, the validity of the second law can only be guaranteed with the Hubble radius greatly smaller than the crossover scale rcof the 5-dimensional DGP model.
文摘Sialon ceramic materials and its main three preparation methods have been outlined, among which preparing sialon powder from Kaolin through the carbothermal reduction and nitridation process is an economical,simple and practical synthesis process.However,the reaction system is complex due to the fact that there exist a lot of influencing factors and several reactions are taking place simutaneously. Partial reactions related to the chemical reaction system of the carbothermal and nitridation process,sialon powder prepared from the purified Kaolin,are analyzed thermodynamically, the systhesis temperature of sialon powder is 1400℃.The theoretical bases used to find the rational process of production are provided.The results prove to be practical.
基金Supported by the National Natural Science Foundation of China.
文摘The thermodynamical properties of silver are calculated by using a recent model of many-body potential from lattice inversion method.The predictions of the phonon dispersion relation,the Grüneisen constant and the linear thermal expansion coefficient are all in coincidence with experiments.Of more importance,the present approach represents an efficient way of building potential functions capable of depicting the thermodynamics of metals for the Finnis-Sinclair model.
文摘Results of the experimental measurements on the partial molar volume of kerosene used as a medium for dissolving TBP are utilized to determine the activity of TBP in the binary kerosene-TBP solution through the application of Gibbs-Duhem equation. The treatment is based on combination of the experimental data with the thermodynamic values available on the compressibility factor of pure kerosene at room temperature. It is shown that the activity of TBP in kerosene has a positive deviation from ideality with an activity coefficient derived as follows:1) at X TBP ≤ 0.01: γ TBP = 42.530, 2) at the 0.01 X TBP 0.2: 3) at the higher TBP concentrations 0.2 X TBP 0.97: and 4) at TBP Raoultian concentrations 0.97 ≤ X TBP:γ TBP = 1. These quantities can be utilized at temperature closed to 298 K.
