The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its...The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.展开更多
Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in d...Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in different sites.A spherical close-packed model for graphite particle was developed.The fractions of surface carbon atoms(SCA) and edge carbon atoms(ECA) were derived in the expression of crystallographic parameters and particle size,and the effects of ECA on the initial irreversible capacity and the mechanisms of action were analyzed and verified.The results show that the atoms on the edge are more active for electrochemical reactions,such as electrolyte decomposition and tendency to form stable bond with other atoms and groups.For the practical graphite particle,corresponding modifying factors were introduced to revise the difference in calculating results.The revised expression is suitable for the calculation of the fractions of SCA and ECA for carbon materials such as graphite,disordered carbon and modified graphite.展开更多
The photoionization and dissociation photoionization of toluene have been studied using quantum chemistry methods. The geometries and frequencies of the reactants, transition states and products have been performed at...The photoionization and dissociation photoionization of toluene have been studied using quantum chemistry methods. The geometries and frequencies of the reactants, transition states and products have been performed at B3LYP/6-311++G(d,p) level, and single-point energy calculations for all the stationary points were carried out at DFT calculations of the optimized structures with the G3B3 level. The ionization energies of toluene and the ap- pearance energies for major fragment ions, C7H7+, C6H5+, C5H6+, C5H5+, are determined to be 8.90, 11.15 or 11.03, 12.72, 13.69, 16.28 eV, respectively, which are all in good agree- ment with published experimental data. With the help of available published experimental data and theoretical results, four dissociative photoionization channels have been proposed: CTHT++H, C6Hs++CH3, C5H6+WC2H2, CsHs++C2H2+H. Transition structures and intermediates for those isomerization processes are determined in this work. Especially, the structures of C5H6+ and C5H5+ produced by dissociative photoionization of toluene have been defined as chain structure in this work with theoretical calculations.展开更多
The Ti-Ni-O ternary system was assessed by means of Calphad method using ternary experimental data in previous study.Isothermal sections at 1 173 and 1 273 K were calculated.The result shows that the present calculate...The Ti-Ni-O ternary system was assessed by means of Calphad method using ternary experimental data in previous study.Isothermal sections at 1 173 and 1 273 K were calculated.The result shows that the present calculated results are in good agreement with most of the experimental results.The consistent model parameter set determined in this work may provide theoretical guidance for the deoxidation of TiNi alloy.展开更多
This paper investigates the mediation of the adoption of computerized accounting system (CAS) on the relationship between environmental uncertainty and organizational performance. The authors use factor analysis, pa...This paper investigates the mediation of the adoption of computerized accounting system (CAS) on the relationship between environmental uncertainty and organizational performance. The authors use factor analysis, path analysis, and regression model to examine the effects of CAS adoption on the relationship between environmental uncertainty and organizational performance. The findings reveal that the adoption level of CAS is positively associated with organizational characteristics, environmental uncertainty, and organizational performance, and the usage of CAS has a statistically significant mediating effect on the relationship between environmental uncertainty and organizational performance. This paper will be significant to business managers in the decision to adopt CAS.展开更多
Flotation behavior and adsorption mechanism of octyl hydroxamic acid(OHA)on wolframite were investigated through flotation experiments,adsorption tests,zeta-potential measurements,infrared spectroscopy and solution ch...Flotation behavior and adsorption mechanism of octyl hydroxamic acid(OHA)on wolframite were investigated through flotation experiments,adsorption tests,zeta-potential measurements,infrared spectroscopy and solution chemistry calculations.Results of flotation and adsorption experiments show that the maximum values of flotation recovery and adsorption capacity occur around p H 9.In term of the solution chemistry calculations,the concentration of metal hydroxamate is greater than that of metal tungstate and metal hydroxyl,and metal hydroxamate compounds are identified to be the main species on wolframite surface at p H region of 8-10,contributing to the increase of OHA adsorption and flotation performance.Results of zeta-potential and IR spectra demonstrate that OHA adsorbs onto wolframite surface by chemisorptions.Hydroxamate ions can bond with Mn_2+/Fe_2+cations of wolframite surface,forming metal hydroxamate compounds,which is a key factor in inducing the hydrophobicity of wolframite under the conditions of maximum flotation.展开更多
An optimization study using a comprehensive 3D, multi-phase, non-isothermal model of a PEM (proton exchange membrane) fuel cell that incorporates significant physical processes and key parameters affecting fuel cell...An optimization study using a comprehensive 3D, multi-phase, non-isothermal model of a PEM (proton exchange membrane) fuel cell that incorporates significant physical processes and key parameters affecting fuel cell performance is presented and discussed in detail. The model accounts for both gas and liquid phase in the same computational domain, and thus allows for the implementation of phase change inside the gas diffusion layers. The model includes the transport of gaseous species, liquid water, protons, energy, and water dissolved in the ion-conducting polymer. Water is assumed to be exchanged among three phases: liquid, vapottr, and dissolved, with equilibrium among these phases being assumed. This model also takes into account convection and diffusion of different species in the channels as well as in the porous gas diffusion layer, heat transfer in the solids as well as in the gases, and electrochemical reactions. The results showed that the present multi-phase model is capable of identifying important parameters for the wetting behaviour of the gas diffusion layers and can be used to identify conditions that might lead to the onset of pore plugging, which has a detrimental effect on the fuel cell performance. This model is used to study the effects of several operating, design, and material parameters on fuel cell performance. Detailed analyses of the fuel cell performance under various operating conditions have been conducted and examined.展开更多
The statistic properties of photon emissions from single semiconductor quantum dots with V-type leveldriven by pulses are investigated theoretically.Based on quantum regression theorem and master equations,the dynamic...The statistic properties of photon emissions from single semiconductor quantum dots with V-type leveldriven by pulses are investigated theoretically.Based on quantum regression theorem and master equations,the dynamicequations of the second-order correlation function of the photon emissions are deduced.The calculated results reveal thatthe efficiency of single photon emissions from two orthogonal polarization eigenstates(|x〉and |y〉)reaches the maximumwhen the input pulses area is about π,and the probability of the cross-polarized single photon emission from |x〉and |y〉decreases with increasing of pulse width.展开更多
Explaining the causes of infeasibility of Boolean formulas has many practical applications in electronic design automation and formal verification of hardware.Furthermore,a minimum explanation of infeasibility that ex...Explaining the causes of infeasibility of Boolean formulas has many practical applications in electronic design automation and formal verification of hardware.Furthermore,a minimum explanation of infeasibility that excludes all irrelevant information is generally of interest.A smallest-cardinality unsatisfiable subset called a minimum unsatisfiable core can provide a succinct explanation of infea-sibility and is valuable for applications.However,little attention has been concentrated on extraction of minimum unsatisfiable core.In this paper,the relationship between maximal satisfiability and mini-mum unsatisfiability is presented and proved,then an efficient ant colony algorithm is proposed to derive an exact or nearly exact minimum unsatisfiable core based on the relationship.Finally,ex-perimental results on practical benchmarks compared with the best known approach are reported,and the results show that the ant colony algorithm strongly outperforms the best previous algorithm.展开更多
Under the method of density functional theory, the geometry structures, values of energy and population analysis of the combo of crown tetraalanylpeptide (C4-AIa) with ions (Xn) are calculated, based on the founda...Under the method of density functional theory, the geometry structures, values of energy and population analysis of the combo of crown tetraalanylpeptide (C4-AIa) with ions (Xn) are calculated, based on the foundation of former studies. It was found that the coronary structure changed little whether in C4-Ala or C4-Ala-Xn, and the electrons transferred between C4-Ala and Xn at the mean time. There were coordinate bonds between Xn+ and the nitrogen from -NH-, hydrogen bonds between Xa and the hydrogen from -NH-, and they became weaker when the radii of ions turned larger. Besides, the values of the single point bonding energy fluctuated gradually as a shape of saddle, but cations and anions located in opposite directions of the center of coronary structure when reach minimum, respectively.展开更多
The effects of 4-(2-hydroxyphenyl)-2-(morpholin-4-yl)-1,3-thiazole(Pr02), 1-(3,5-dibromo-2-hydroxyphenyl)-1-oxoethan-2-yl-N,N-diethyldithiocarbamate(Pr04) and 1-(5-bromo-2-hydroxy-3-methylphenyl)-1-oxoethan-2-yl-Oethy...The effects of 4-(2-hydroxyphenyl)-2-(morpholin-4-yl)-1,3-thiazole(Pr02), 1-(3,5-dibromo-2-hydroxyphenyl)-1-oxoethan-2-yl-N,N-diethyldithiocarbamate(Pr04) and 1-(5-bromo-2-hydroxy-3-methylphenyl)-1-oxoethan-2-yl-Oethyl xanthate(Pr06) on the aqueous oxidation of chalcopyrite(CuFeS2) in air-equilibrated solution at a temperature of 25 ℃ and a pH of 2.5 were studied. The effects were investigated by using potentiodynamic polarization, electrochemical impedance spectroscopy(EIS), scanning electron microscopy coupled with energy dispersive X-ray(SEM/EDX) analysis, aqueous batch experiments, Fourier transform infrared(FTIR) spectroscopy, Raman scattering and quantum chemical calculations. It is found that the anodic current densities decrease in the order of EtOH > Pr02 > Pr04 > Pr06. These results, along with those of the EIS measurements, show that Pr02, Pr04 and Pr06 are effective anodic inhibitors of chalcopyrite aqueous oxidation. Both Raman scattering and FTIR spectroscopy indicate that the elemental sulfur, polysulfide and ferric oxyhydroxides that form on the surface of the mineral are not responsible when it comes to the aqueous oxidation inhibition of chalcopyrite. Quantum chemical calculations show that the adsorption of the tested compounds on the chalcopyrite surface is energetically favorable and so, it can explain the inhibiting effects that were observed.展开更多
Molecular dipole moments computed at the levels of HF/STO-3G, HF/6-31G(d, p), HF/6-311+G(2d, 2p), MP2/6-31G(d, p) and MP2/6-311+G(2d, 2p) have been investigated. HF/6-311+G(2d, 2p) was found to be the relatively good ...Molecular dipole moments computed at the levels of HF/STO-3G, HF/6-31G(d, p), HF/6-311+G(2d, 2p), MP2/6-31G(d, p) and MP2/6-311+G(2d, 2p) have been investigated. HF/6-311+G(2d, 2p) was found to be the relatively good choice to compute MKS charges for reproducing the experimental values of molecular dipole moments. Root mean square deviation of computed dipole moments for 21 small polar molecules is about 0.1969 D.展开更多
The thermodynamic stability and lithiated/delithiated potentials of LiFexMn1-xPO4 were studied with density functional theorical calculations. The results show that the formation free energy of the LiFexMn1-xPO4 solid...The thermodynamic stability and lithiated/delithiated potentials of LiFexMn1-xPO4 were studied with density functional theorical calculations. The results show that the formation free energy of the LiFexMn1-xPO4 solid solution is slightly higher than that of the phase-separated mixture of LiFePO4 and LiMnPO4, and the two forms may co-exist in the actual LiFexMn1-xPO4 materials. The calculation manifests that the lithiated/delithiated potentials of LiFexMn1-xPO4 solid solutions vary via the Mn/Fe ratio and the spatial arrangements of the transition metal ions, and the result is used to explain the shape of capacity-voltage curves. Experimentally, we have synthesized the LiFexMn1-xPO4 materials by solid-phase reaction method. The existence of the LiFexMn1-xPO4 solid solution is thought to be responsible for the appearance of additional capacity-voltage plateau observed in the experiment.展开更多
An improved decision tree method for web information retrieval with self-mapping attributes is proposed.The self-mapping tree has a value of self-mapping attribute in its internal node,and information based on dissimi...An improved decision tree method for web information retrieval with self-mapping attributes is proposed.The self-mapping tree has a value of self-mapping attribute in its internal node,and information based on dissimilarity between a pair of mapping sequences.This method selects self-mapping which exists between data by exhaustive search based on relation and attribute information.Experimental results confirm that the improved method constructs comprehensive and accurate decision tree.Moreover,an example shows that the self-mapping decision tree is promising for data mining and knowledge discovery.展开更多
The electronic structures,chemical bonding,elastic and optical properties of the novel hP24 phase WB3 were investigated by using density-functional theory(DFT) within generalized gradient approximation(GGA).The calcul...The electronic structures,chemical bonding,elastic and optical properties of the novel hP24 phase WB3 were investigated by using density-functional theory(DFT) within generalized gradient approximation(GGA).The calculated energy band structures show that the hP24 phase WB3 is metallic material.The density of state(DOS) and the partial density of state(PDOS) calculations show that the DOS near the Fermi level is mainly from the W 5d and B 2p states.Population analysis suggests that the chemical bonding in hP24-WB3 has predominantly covalent characteristics with mixed covalent-ionic characteristics.Basic physical properties,such as lattice constant,bulk modulus,shear modulus and elastic constants Cij were calculated.The elastic modulus E and Poisson ratio υ were also predicted.The results show that hP24-WB3 phase is mechanically stable and behaves in a brittle manner.Detailed analysis of all optical functions reveals that WB3 is a better dielectric material,and reflectivity spectra show that WB3 can be promised as good coating material in the energy regions of 8.5-11.4 eV and 14.5-15.5 eV.展开更多
基金supported by the National Natural Science Foundation of China(22322304,22273092,22373095)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450101)+2 种基金the Innovation Program for Quantum Science and Technology(2021ZD0303306)the USTC Tang ScholarThe authors wish to acknowledge the Supercomputing Center of the USTC for providing computational resources.
文摘The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.
基金Project (09001232) supported by the Doctoral Foundation of Henan University of Science and Technology,China
文摘Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in different sites.A spherical close-packed model for graphite particle was developed.The fractions of surface carbon atoms(SCA) and edge carbon atoms(ECA) were derived in the expression of crystallographic parameters and particle size,and the effects of ECA on the initial irreversible capacity and the mechanisms of action were analyzed and verified.The results show that the atoms on the edge are more active for electrochemical reactions,such as electrolyte decomposition and tendency to form stable bond with other atoms and groups.For the practical graphite particle,corresponding modifying factors were introduced to revise the difference in calculating results.The revised expression is suitable for the calculation of the fractions of SCA and ECA for carbon materials such as graphite,disordered carbon and modified graphite.
文摘The photoionization and dissociation photoionization of toluene have been studied using quantum chemistry methods. The geometries and frequencies of the reactants, transition states and products have been performed at B3LYP/6-311++G(d,p) level, and single-point energy calculations for all the stationary points were carried out at DFT calculations of the optimized structures with the G3B3 level. The ionization energies of toluene and the ap- pearance energies for major fragment ions, C7H7+, C6H5+, C5H6+, C5H5+, are determined to be 8.90, 11.15 or 11.03, 12.72, 13.69, 16.28 eV, respectively, which are all in good agree- ment with published experimental data. With the help of available published experimental data and theoretical results, four dissociative photoionization channels have been proposed: CTHT++H, C6Hs++CH3, C5H6+WC2H2, CsHs++C2H2+H. Transition structures and intermediates for those isomerization processes are determined in this work. Especially, the structures of C5H6+ and C5H5+ produced by dissociative photoionization of toluene have been defined as chain structure in this work with theoretical calculations.
基金Project (10520706400) supported by the Science and Technology Commission of Shanghai Municipality,ChinaProject (2007CB613606) supported by the National Basic Research Program of ChinaProjects (50774052,51074105) supported by the National Natural Science Foundation of China
文摘The Ti-Ni-O ternary system was assessed by means of Calphad method using ternary experimental data in previous study.Isothermal sections at 1 173 and 1 273 K were calculated.The result shows that the present calculated results are in good agreement with most of the experimental results.The consistent model parameter set determined in this work may provide theoretical guidance for the deoxidation of TiNi alloy.
文摘This paper investigates the mediation of the adoption of computerized accounting system (CAS) on the relationship between environmental uncertainty and organizational performance. The authors use factor analysis, path analysis, and regression model to examine the effects of CAS adoption on the relationship between environmental uncertainty and organizational performance. The findings reveal that the adoption level of CAS is positively associated with organizational characteristics, environmental uncertainty, and organizational performance, and the usage of CAS has a statistically significant mediating effect on the relationship between environmental uncertainty and organizational performance. This paper will be significant to business managers in the decision to adopt CAS.
基金Project(2014CB643402) supported by the National Basic Research Program of ChinaProject(CX2013B082) supported by the Hunan Provincial Innovation Foundation for Postgraduate,China
文摘Flotation behavior and adsorption mechanism of octyl hydroxamic acid(OHA)on wolframite were investigated through flotation experiments,adsorption tests,zeta-potential measurements,infrared spectroscopy and solution chemistry calculations.Results of flotation and adsorption experiments show that the maximum values of flotation recovery and adsorption capacity occur around p H 9.In term of the solution chemistry calculations,the concentration of metal hydroxamate is greater than that of metal tungstate and metal hydroxyl,and metal hydroxamate compounds are identified to be the main species on wolframite surface at p H region of 8-10,contributing to the increase of OHA adsorption and flotation performance.Results of zeta-potential and IR spectra demonstrate that OHA adsorbs onto wolframite surface by chemisorptions.Hydroxamate ions can bond with Mn_2+/Fe_2+cations of wolframite surface,forming metal hydroxamate compounds,which is a key factor in inducing the hydrophobicity of wolframite under the conditions of maximum flotation.
基金Project supported by the Postgraduate Programs of the International Technological University (ITU), London, UK
文摘An optimization study using a comprehensive 3D, multi-phase, non-isothermal model of a PEM (proton exchange membrane) fuel cell that incorporates significant physical processes and key parameters affecting fuel cell performance is presented and discussed in detail. The model accounts for both gas and liquid phase in the same computational domain, and thus allows for the implementation of phase change inside the gas diffusion layers. The model includes the transport of gaseous species, liquid water, protons, energy, and water dissolved in the ion-conducting polymer. Water is assumed to be exchanged among three phases: liquid, vapottr, and dissolved, with equilibrium among these phases being assumed. This model also takes into account convection and diffusion of different species in the channels as well as in the porous gas diffusion layer, heat transfer in the solids as well as in the gases, and electrochemical reactions. The results showed that the present multi-phase model is capable of identifying important parameters for the wetting behaviour of the gas diffusion layers and can be used to identify conditions that might lead to the onset of pore plugging, which has a detrimental effect on the fuel cell performance. This model is used to study the effects of several operating, design, and material parameters on fuel cell performance. Detailed analyses of the fuel cell performance under various operating conditions have been conducted and examined.
基金National Natural Science Foundation of China under Grant Nos.10534030 and CAST200729
文摘The statistic properties of photon emissions from single semiconductor quantum dots with V-type leveldriven by pulses are investigated theoretically.Based on quantum regression theorem and master equations,the dynamicequations of the second-order correlation function of the photon emissions are deduced.The calculated results reveal thatthe efficiency of single photon emissions from two orthogonal polarization eigenstates(|x〉and |y〉)reaches the maximumwhen the input pulses area is about π,and the probability of the cross-polarized single photon emission from |x〉and |y〉decreases with increasing of pulse width.
基金the National Natural Science Foundation of China (No.60603088)
文摘Explaining the causes of infeasibility of Boolean formulas has many practical applications in electronic design automation and formal verification of hardware.Furthermore,a minimum explanation of infeasibility that excludes all irrelevant information is generally of interest.A smallest-cardinality unsatisfiable subset called a minimum unsatisfiable core can provide a succinct explanation of infea-sibility and is valuable for applications.However,little attention has been concentrated on extraction of minimum unsatisfiable core.In this paper,the relationship between maximal satisfiability and mini-mum unsatisfiability is presented and proved,then an efficient ant colony algorithm is proposed to derive an exact or nearly exact minimum unsatisfiable core based on the relationship.Finally,ex-perimental results on practical benchmarks compared with the best known approach are reported,and the results show that the ant colony algorithm strongly outperforms the best previous algorithm.
文摘Under the method of density functional theory, the geometry structures, values of energy and population analysis of the combo of crown tetraalanylpeptide (C4-AIa) with ions (Xn) are calculated, based on the foundation of former studies. It was found that the coronary structure changed little whether in C4-Ala or C4-Ala-Xn, and the electrons transferred between C4-Ala and Xn at the mean time. There were coordinate bonds between Xn+ and the nitrogen from -NH-, hydrogen bonds between Xa and the hydrogen from -NH-, and they became weaker when the radii of ions turned larger. Besides, the values of the single point bonding energy fluctuated gradually as a shape of saddle, but cations and anions located in opposite directions of the center of coronary structure when reach minimum, respectively.
基金partly supported by a grant of the Romanian National Authority for Scientific Research,CNDI-UEFISCDI,project number 51/2012。
文摘The effects of 4-(2-hydroxyphenyl)-2-(morpholin-4-yl)-1,3-thiazole(Pr02), 1-(3,5-dibromo-2-hydroxyphenyl)-1-oxoethan-2-yl-N,N-diethyldithiocarbamate(Pr04) and 1-(5-bromo-2-hydroxy-3-methylphenyl)-1-oxoethan-2-yl-Oethyl xanthate(Pr06) on the aqueous oxidation of chalcopyrite(CuFeS2) in air-equilibrated solution at a temperature of 25 ℃ and a pH of 2.5 were studied. The effects were investigated by using potentiodynamic polarization, electrochemical impedance spectroscopy(EIS), scanning electron microscopy coupled with energy dispersive X-ray(SEM/EDX) analysis, aqueous batch experiments, Fourier transform infrared(FTIR) spectroscopy, Raman scattering and quantum chemical calculations. It is found that the anodic current densities decrease in the order of EtOH > Pr02 > Pr04 > Pr06. These results, along with those of the EIS measurements, show that Pr02, Pr04 and Pr06 are effective anodic inhibitors of chalcopyrite aqueous oxidation. Both Raman scattering and FTIR spectroscopy indicate that the elemental sulfur, polysulfide and ferric oxyhydroxides that form on the surface of the mineral are not responsible when it comes to the aqueous oxidation inhibition of chalcopyrite. Quantum chemical calculations show that the adsorption of the tested compounds on the chalcopyrite surface is energetically favorable and so, it can explain the inhibiting effects that were observed.
基金The project was supported by the National Science Foundation (29773021) Provincial Educational Foundation of Jiangsu (98KJB150001).
文摘Molecular dipole moments computed at the levels of HF/STO-3G, HF/6-31G(d, p), HF/6-311+G(2d, 2p), MP2/6-31G(d, p) and MP2/6-311+G(2d, 2p) have been investigated. HF/6-311+G(2d, 2p) was found to be the relatively good choice to compute MKS charges for reproducing the experimental values of molecular dipole moments. Root mean square deviation of computed dipole moments for 21 small polar molecules is about 0.1969 D.
基金supported by the Science and Technology Foundation of Jiangsu Province(BK20151237)the Special Nano-technology of Suzhou(ZXG2013004)+2 种基金USTC-NSRL Association Fundingthe Collaborative Innovation Centre of Suzhou Nano Science and Technologythe Supercomputation Center of USTC
文摘The thermodynamic stability and lithiated/delithiated potentials of LiFexMn1-xPO4 were studied with density functional theorical calculations. The results show that the formation free energy of the LiFexMn1-xPO4 solid solution is slightly higher than that of the phase-separated mixture of LiFePO4 and LiMnPO4, and the two forms may co-exist in the actual LiFexMn1-xPO4 materials. The calculation manifests that the lithiated/delithiated potentials of LiFexMn1-xPO4 solid solutions vary via the Mn/Fe ratio and the spatial arrangements of the transition metal ions, and the result is used to explain the shape of capacity-voltage curves. Experimentally, we have synthesized the LiFexMn1-xPO4 materials by solid-phase reaction method. The existence of the LiFexMn1-xPO4 solid solution is thought to be responsible for the appearance of additional capacity-voltage plateau observed in the experiment.
文摘An improved decision tree method for web information retrieval with self-mapping attributes is proposed.The self-mapping tree has a value of self-mapping attribute in its internal node,and information based on dissimilarity between a pair of mapping sequences.This method selects self-mapping which exists between data by exhaustive search based on relation and attribute information.Experimental results confirm that the improved method constructs comprehensive and accurate decision tree.Moreover,an example shows that the self-mapping decision tree is promising for data mining and knowledge discovery.
基金Project(11271121)supported by the National Natural Science Foundation of ChinaProject(11JJ2002)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(11K038)supported by Key Laboratory of Computational and Stochastic Mathematics of Ministry of Education of ChinaProject(2013GK3130)supported by the Scientific and Technological Plan of Hunan Province,China
文摘The electronic structures,chemical bonding,elastic and optical properties of the novel hP24 phase WB3 were investigated by using density-functional theory(DFT) within generalized gradient approximation(GGA).The calculated energy band structures show that the hP24 phase WB3 is metallic material.The density of state(DOS) and the partial density of state(PDOS) calculations show that the DOS near the Fermi level is mainly from the W 5d and B 2p states.Population analysis suggests that the chemical bonding in hP24-WB3 has predominantly covalent characteristics with mixed covalent-ionic characteristics.Basic physical properties,such as lattice constant,bulk modulus,shear modulus and elastic constants Cij were calculated.The elastic modulus E and Poisson ratio υ were also predicted.The results show that hP24-WB3 phase is mechanically stable and behaves in a brittle manner.Detailed analysis of all optical functions reveals that WB3 is a better dielectric material,and reflectivity spectra show that WB3 can be promised as good coating material in the energy regions of 8.5-11.4 eV and 14.5-15.5 eV.