The results of predicting thermodynamic properties in the full composition range of Ti-Al binary melts in a temperature range from 1973 to 2273 K were obtained by coupling with the developed thermodynamic model for ca...The results of predicting thermodynamic properties in the full composition range of Ti-Al binary melts in a temperature range from 1973 to 2273 K were obtained by coupling with the developed thermodynamic model for calculating mass action concentration N_i of structural units in Ti-Al system based on the atom and molecule coexistence theory(AMCT). Temperature dependence of the activity coefficients of Ti and Al in natural logarithmic form in the infinitely dilute solution(0x_(Ti)0.01) of Ti-Al binary melts was also determined from the calculated activity coefficients of Ti and Al at temperatures of 1973, 2073, 2173, and 2273 K. The standard molar Gibbs free energy change of dissolving pure liquid element i(l) for forming 1%(mass fraction) element i in Ti-Al binary melts further was deduced. With the aid of this model, meanwhile, the determined excess thermodynamic properties, such as the excess molar mixing Gibbs free energy/entropy/enthalpy were also calculated.展开更多
There exists widely incomplete knowledge all over the world, but incomplete knowledge still cannot be dealt with in the process of ontology construction. Hence, a method for fuzzy ontology construction based on incomp...There exists widely incomplete knowledge all over the world, but incomplete knowledge still cannot be dealt with in the process of ontology construction. Hence, a method for fuzzy ontology construction based on incomplete knowledge is proposed. First, the calculation principle of the attribute weight of the ontology concept is presented, and the calculation function of the attribute weight is derived through experiments. Then, the membership degree of the incomplete individual to the concept is computed. Finally, the incomplete individual is classified according to the principle of the variable precision rough set model. The experimental results show that the average precision of the classification of the incomplete individuals is 81.7% when the common attributes are omitted and that it is difficult to classify the incomplete individuals correctly when the private attributes are omitted. This method is significant for handling incomplete knowledge in the process of ontology construction.展开更多
Sandwich plate systems (SPS) are advanced materials that have begun to receive extensive attention in naval architecture and ocean engineering.At present, according to the rules of classification societies, a mixture ...Sandwich plate systems (SPS) are advanced materials that have begun to receive extensive attention in naval architecture and ocean engineering.At present, according to the rules of classification societies, a mixture of shell and solid elements are required to simulate an SPS.Based on the principle of stiffness decomposition, a new numerical simulation method for shell elements was proposed.In accordance with the principle of stiffness decomposition, the total stiffness can be decomposed into the bending stiffness and shear stiffness.Displacement and stress response related to bending stiffness was calculated with the laminated shell element.Displacement and stress response due to shear was calculated by use of a computational code write by FORTRAN language.Then the total displacement and stress response for the SPS was obtained by adding together these two parts of total displacement and stress.Finally, a rectangular SPS plate and a double-bottom structure were used for a simulation.The results show that the deflection simulated by the elements proposed in the paper is larger than the same simulated by solid elements and the analytical solution according to Hoff theory and approximate to the same simulated by the mixture of shell-solid elements, and the stress simulated by the elements proposed in the paper is approximate to the other simulating methods.So compared with calculations based on a mixture of shell and solid elements, the numerical simulation method given in the paper is more efficient and easier to do.展开更多
Changes of dyeing behavior of wool after stretching - setting treatment are studied.Effects of stretching - setting on wool structure are analyzed.It is concluded that stretching - setting treatment not only reduces w...Changes of dyeing behavior of wool after stretching - setting treatment are studied.Effects of stretching - setting on wool structure are analyzed.It is concluded that stretching - setting treatment not only reduces wool diameter and increases wool length,but also brings about low-temperature dyeing of wool.展开更多
Litbium intercalated bilayer graphene has been investigated using first-principles density functional theory calculations. Re- sults show that there exist AB and AA stacking sequences for bilayer graphene in which the...Litbium intercalated bilayer graphene has been investigated using first-principles density functional theory calculations. Re- sults show that there exist AB and AA stacking sequences for bilayer graphene in which the latter is more favorable for the Li storage and the former will evolve into the latter with the intercalation of Li ions. The relationship between the interlayer dis- tance of two graphene sheets and the intercalated capacity of Li ions is discussed, It is found that structural defect is identified to store Li ions more favorably than pristine bilayer graphene and an isolated C atom vacancy in bilayer graphene can capture three Li ions between two graphene sheets.展开更多
Cooling water is an important part in a Spallation Neutron Source target cooling system, but the unstable vortexes at the exits of the slits between every two tungsten target slices have a negative impact on the stabl...Cooling water is an important part in a Spallation Neutron Source target cooling system, but the unstable vortexes at the exits of the slits between every two tungsten target slices have a negative impact on the stable running of the target system. We apply the field synergy principle for fluid flow to obtain the optimal flow field, which has a uniform velocity distribution without eddy, and then, optimize the geometrical structure of the cooling water flow channel based on the optimal flow field. The results show that when the cooling water flows in the optimized channel, the eddy sizes decrease, the time fluctuations of velocity and pressure almost vanish, and the volume flow rates of the cooling water in each parallel slit are uniform. Therefore, it effectively improves the running stability of the target system with the premise of satisfying the target heat load.展开更多
A recently developed B-spline algorithm is extended and utilized to calculate excited states of He atoms in the presence of strong magnetic fields.Binding energies are presented for He in the five excited atomic state...A recently developed B-spline algorithm is extended and utilized to calculate excited states of He atoms in the presence of strong magnetic fields.Binding energies are presented for He in the five excited atomic states 210-+,110-,210-,11(-1)+,and 2 1(1) + with magnetic field strength ranging from 0.0001 to 10 a.u.The obtained energies are compared with available theoretical data,and found to be in good agreement.We investigate influence of magnetic fields on atomic structures of multielectron atoms,and illustrate that how electron probability density distributions change with increasing magnetic field strength.The current approach is directly applicable to simulations of discrete spectra for He atoms in the atmospheres of magnetized white dwarf stars.展开更多
We have investigated the effects of B impurities on the structure and mechanical properties of NiA1 intermetallics by using a first-principles pseudopotential total-energy method, based on the density functional theor...We have investigated the effects of B impurities on the structure and mechanical properties of NiA1 intermetallics by using a first-principles pseudopotential total-energy method, based on the density functional theory with a generalized gradient approximation. We found that the impurity B atoms can either replace Ni atoms or Al atoms or both, depending on the surround- ing environment. We demonstrated that the presence of B will cause an increase in brittleness and a decrease in the ductility of NiAI for the Al-substitutional case, while causing an increase in the ductility of NiAl for the Ni-subtitutional case, based on the calculated elastic constants and the empirical criterions. This indicates that the effects of B impurities on the mechanical prop- erties of NiAl intermetallics are quite composition-dependent.展开更多
This paper is proposed to understand the interaction of porphyrin layers with diatomic molecules interacting at their interior regions by applying ab initio and density functional theory (DFT) methods. We have used ...This paper is proposed to understand the interaction of porphyrin layers with diatomic molecules interacting at their interior regions by applying ab initio and density functional theory (DFT) methods. We have used NO, GO, and O2 diatomic molecules to interact with the porphyrin layers. The most common Fe-centered metalloporphyrin structure with tetra-pyrrlic rings having N4 core is chosen for the study. The optimization of Porphyrin-Porphyrin (PI-PII) and Porphyrin-Diatomic molecule-Porphyrin (P1-AB-P11) (AB = NO, CO, and 02) complexes are performed using HF method. In order to understand the planarity and appropriate stacking size of porphyrins and also to infer the separation of diatomic molecules between porphyrin layers the behavior of PI-AB-PH complexes (where AB = NO, CO, and 02) are analyzed using structural properties and molecular electrostatic potentials (MEP). The MEPs are caiculated using hybrid exchange correlation functional B3PW91 of DFT Mong with 6-31+G basis set for the PI-PH and PI-AB-Pzz complexes obtained from HF method.展开更多
The structural, electronic and spectroscopic properties of monomer FPt (2-(4′,6′-difluorophenyl)pyridinato-N,C2′)(2,4-pentanedionato-O,O) (1) and dimer [FPt]2 (2) were explored within the density functional theory ...The structural, electronic and spectroscopic properties of monomer FPt (2-(4′,6′-difluorophenyl)pyridinato-N,C2′)(2,4-pentanedionato-O,O) (1) and dimer [FPt]2 (2) were explored within the density functional theory (DFT) and time-dependent DFT (TD-DFT). The calculated geometry parameters and spectroscopic results agree well with the experimental observation. In the ground state, FPt exists in the form of monomer, while in the excited state, dimer [FPt]2 forms with a Pt-Pt contraction of 0.05 nm due to the promotion of σ[dz2(Pt2)] to π*(phenylryridyl) and σ[pz(Pt2)]. Transition properties of monomer and excimer are different in nature: the former originates from mixed transitions of 3MLCT and 3ILCT, while the latter is dominated by 3MMLCT transition.展开更多
By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of the dihydroazulene optical molecular switch. Th...By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of the dihydroazulene optical molecular switch. Three kinds of adsorption sites including the hollow, bridge and top sites are studied. The two forms of this molecule, namely the open form and the closed form, can reversibly switch from each other upon photoexcitation. Their transmission spectra are remarkably distinctive. Theoretical results show that the current of the closed form is always significantly larger than that of the open form for all three adsorption sites, which promises this system as possibly one of the good candidates for optical switches due to its unique advantage, and which may have some potential applications in the future molecular circuit.展开更多
In this work, a second order smoothed particle hydrodynamics is derived for the study of relativistic heavy ion collisions. The hydrodynamical equation of motion is formulated in terms of the variational principle. In...In this work, a second order smoothed particle hydrodynamics is derived for the study of relativistic heavy ion collisions. The hydrodynamical equation of motion is formulated in terms of the variational principle. In order to describe the fluid of high energy density but of low baryon density, the entropy is taken as the base quantity for the interpolation. The smoothed particle hydrodynamics algorithm employed in this study is of the second order, which guarantees better particle consistency. Furthermore, it is shown that the variational principle preserves the translational invariance of the system, and therefore improves the accuracy of the method. A brief discussion on the potential implications of the model in heavy ion physics as well as in general relativity are also presented.展开更多
基金Project(U1560203)supported by the Joint Funds of the National Natural Science Foundation of ChinaProject(51274031)supported by the National Natural Science Foundation of China
文摘The results of predicting thermodynamic properties in the full composition range of Ti-Al binary melts in a temperature range from 1973 to 2273 K were obtained by coupling with the developed thermodynamic model for calculating mass action concentration N_i of structural units in Ti-Al system based on the atom and molecule coexistence theory(AMCT). Temperature dependence of the activity coefficients of Ti and Al in natural logarithmic form in the infinitely dilute solution(0x_(Ti)0.01) of Ti-Al binary melts was also determined from the calculated activity coefficients of Ti and Al at temperatures of 1973, 2073, 2173, and 2273 K. The standard molar Gibbs free energy change of dissolving pure liquid element i(l) for forming 1%(mass fraction) element i in Ti-Al binary melts further was deduced. With the aid of this model, meanwhile, the determined excess thermodynamic properties, such as the excess molar mixing Gibbs free energy/entropy/enthalpy were also calculated.
基金supported by the Beijing Natural Science Foundation under Grant No.4123094 the Science and Technology Project of Beijing Municipal Commission of Education under Grants No.KM201110028020,No. KM201010028019 Beijing Key Construction Discipline“Computer Application Technology”
文摘There exists widely incomplete knowledge all over the world, but incomplete knowledge still cannot be dealt with in the process of ontology construction. Hence, a method for fuzzy ontology construction based on incomplete knowledge is proposed. First, the calculation principle of the attribute weight of the ontology concept is presented, and the calculation function of the attribute weight is derived through experiments. Then, the membership degree of the incomplete individual to the concept is computed. Finally, the incomplete individual is classified according to the principle of the variable precision rough set model. The experimental results show that the average precision of the classification of the incomplete individuals is 81.7% when the common attributes are omitted and that it is difficult to classify the incomplete individuals correctly when the private attributes are omitted. This method is significant for handling incomplete knowledge in the process of ontology construction.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No.HEUCFR 1003
文摘Sandwich plate systems (SPS) are advanced materials that have begun to receive extensive attention in naval architecture and ocean engineering.At present, according to the rules of classification societies, a mixture of shell and solid elements are required to simulate an SPS.Based on the principle of stiffness decomposition, a new numerical simulation method for shell elements was proposed.In accordance with the principle of stiffness decomposition, the total stiffness can be decomposed into the bending stiffness and shear stiffness.Displacement and stress response related to bending stiffness was calculated with the laminated shell element.Displacement and stress response due to shear was calculated by use of a computational code write by FORTRAN language.Then the total displacement and stress response for the SPS was obtained by adding together these two parts of total displacement and stress.Finally, a rectangular SPS plate and a double-bottom structure were used for a simulation.The results show that the deflection simulated by the elements proposed in the paper is larger than the same simulated by solid elements and the analytical solution according to Hoff theory and approximate to the same simulated by the mixture of shell-solid elements, and the stress simulated by the elements proposed in the paper is approximate to the other simulating methods.So compared with calculations based on a mixture of shell and solid elements, the numerical simulation method given in the paper is more efficient and easier to do.
文摘Changes of dyeing behavior of wool after stretching - setting treatment are studied.Effects of stretching - setting on wool structure are analyzed.It is concluded that stretching - setting treatment not only reduces wool diameter and increases wool length,but also brings about low-temperature dyeing of wool.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50802089 and 51072183)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education of China (Grant No. [2008] 890)the Natural Science Foundation of Zhejiang Province (Grant No. Y4090280)
文摘Litbium intercalated bilayer graphene has been investigated using first-principles density functional theory calculations. Re- sults show that there exist AB and AA stacking sequences for bilayer graphene in which the latter is more favorable for the Li storage and the former will evolve into the latter with the intercalation of Li ions. The relationship between the interlayer dis- tance of two graphene sheets and the intercalated capacity of Li ions is discussed, It is found that structural defect is identified to store Li ions more favorably than pristine bilayer graphene and an isolated C atom vacancy in bilayer graphene can capture three Li ions between two graphene sheets.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51006060, 51036003)the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No.201150)
文摘Cooling water is an important part in a Spallation Neutron Source target cooling system, but the unstable vortexes at the exits of the slits between every two tungsten target slices have a negative impact on the stable running of the target system. We apply the field synergy principle for fluid flow to obtain the optimal flow field, which has a uniform velocity distribution without eddy, and then, optimize the geometrical structure of the cooling water flow channel based on the optimal flow field. The results show that when the cooling water flows in the optimized channel, the eddy sizes decrease, the time fluctuations of velocity and pressure almost vanish, and the volume flow rates of the cooling water in each parallel slit are uniform. Therefore, it effectively improves the running stability of the target system with the premise of satisfying the target heat load.
基金Supported by the National Science Foundation of USA under Grant No. 0630370National Natural Science Foundation of Chinaunder Grant Nos. 90403028 and 11074260
文摘A recently developed B-spline algorithm is extended and utilized to calculate excited states of He atoms in the presence of strong magnetic fields.Binding energies are presented for He in the five excited atomic states 210-+,110-,210-,11(-1)+,and 2 1(1) + with magnetic field strength ranging from 0.0001 to 10 a.u.The obtained energies are compared with available theoretical data,and found to be in good agreement.We investigate influence of magnetic fields on atomic structures of multielectron atoms,and illustrate that how electron probability density distributions change with increasing magnetic field strength.The current approach is directly applicable to simulations of discrete spectra for He atoms in the atmospheres of magnetized white dwarf stars.
基金supported by the Basic Research Project of High Education (Grant No. ZXH2009C004)the Foundation of CAUC (Grant No. 09QD06X)
文摘We have investigated the effects of B impurities on the structure and mechanical properties of NiA1 intermetallics by using a first-principles pseudopotential total-energy method, based on the density functional theory with a generalized gradient approximation. We found that the impurity B atoms can either replace Ni atoms or Al atoms or both, depending on the surround- ing environment. We demonstrated that the presence of B will cause an increase in brittleness and a decrease in the ductility of NiAI for the Al-substitutional case, while causing an increase in the ductility of NiAl for the Ni-subtitutional case, based on the calculated elastic constants and the empirical criterions. This indicates that the effects of B impurities on the mechanical prop- erties of NiAl intermetallics are quite composition-dependent.
基金the Science and Engineering Research Board (SERB), India for awarding the fast track project (Project No: SB/FTP/PS-096/2013)
文摘This paper is proposed to understand the interaction of porphyrin layers with diatomic molecules interacting at their interior regions by applying ab initio and density functional theory (DFT) methods. We have used NO, GO, and O2 diatomic molecules to interact with the porphyrin layers. The most common Fe-centered metalloporphyrin structure with tetra-pyrrlic rings having N4 core is chosen for the study. The optimization of Porphyrin-Porphyrin (PI-PII) and Porphyrin-Diatomic molecule-Porphyrin (P1-AB-P11) (AB = NO, CO, and 02) complexes are performed using HF method. In order to understand the planarity and appropriate stacking size of porphyrins and also to infer the separation of diatomic molecules between porphyrin layers the behavior of PI-AB-PH complexes (where AB = NO, CO, and 02) are analyzed using structural properties and molecular electrostatic potentials (MEP). The MEPs are caiculated using hybrid exchange correlation functional B3PW91 of DFT Mong with 6-31+G basis set for the PI-PH and PI-AB-Pzz complexes obtained from HF method.
基金supported by the Research Fund for the Doctoral Program of Higher Education of China (200801831004)the Fundamental Research Funds for the Central Universities (HIT.NSRIF.2009083)+1 种基金the National Natural Science Foundation of China (20703015)the Program for New Century Excellent Talents of Common Universities of Heilongjiang Province (1154-NCET-010)
文摘The structural, electronic and spectroscopic properties of monomer FPt (2-(4′,6′-difluorophenyl)pyridinato-N,C2′)(2,4-pentanedionato-O,O) (1) and dimer [FPt]2 (2) were explored within the density functional theory (DFT) and time-dependent DFT (TD-DFT). The calculated geometry parameters and spectroscopic results agree well with the experimental observation. In the ground state, FPt exists in the form of monomer, while in the excited state, dimer [FPt]2 forms with a Pt-Pt contraction of 0.05 nm due to the promotion of σ[dz2(Pt2)] to π*(phenylryridyl) and σ[pz(Pt2)]. Transition properties of monomer and excimer are different in nature: the former originates from mixed transitions of 3MLCT and 3ILCT, while the latter is dominated by 3MMLCT transition.
基金supported by the National Natural Science Foundation of China (Grant No. 11004156)the National Basic Research Program of China (Grant No. 2009CB929204)+1 种基金the Education Department Foundation of Shaanxi Province, China (Grant No. 09JK461)the Fundament Research of Xi’an Polytechnic University (Grant No. 09XG09)
文摘By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of the dihydroazulene optical molecular switch. Three kinds of adsorption sites including the hollow, bridge and top sites are studied. The two forms of this molecule, namely the open form and the closed form, can reversibly switch from each other upon photoexcitation. Their transmission spectra are remarkably distinctive. Theoretical results show that the current of the closed form is always significantly larger than that of the open form for all three adsorption sites, which promises this system as possibly one of the good candidates for optical switches due to its unique advantage, and which may have some potential applications in the future molecular circuit.
基金financial support from Funda o de Amparo à Pesquisa do Estado de So Paulo (FAPESP)Funda o de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)+2 种基金Fundao de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordena o de Aperfei oamento de Pessoal de Nível Superior (CAPES)
文摘In this work, a second order smoothed particle hydrodynamics is derived for the study of relativistic heavy ion collisions. The hydrodynamical equation of motion is formulated in terms of the variational principle. In order to describe the fluid of high energy density but of low baryon density, the entropy is taken as the base quantity for the interpolation. The smoothed particle hydrodynamics algorithm employed in this study is of the second order, which guarantees better particle consistency. Furthermore, it is shown that the variational principle preserves the translational invariance of the system, and therefore improves the accuracy of the method. A brief discussion on the potential implications of the model in heavy ion physics as well as in general relativity are also presented.