Based on the available experimental data,the Bi-Ni binary system was optimized thermodynamically by the CALPHAD method.The solution phases,including liquid,fcc_A1（Ni） and rhombohedral_A7（Bi）,were described as subs...Based on the available experimental data,the Bi-Ni binary system was optimized thermodynamically by the CALPHAD method.The solution phases,including liquid,fcc_A1（Ni） and rhombohedral_A7（Bi）,were described as substitutional solution phases,of which the excess Gibbs energies were expressed with the Redlich-Kister polynomial.The intermetallic compound,BiNi,was modeled using three sublattices（Bi）（Ni,Va）（Ni,Va） considering its crystal structure（NiAs-type） and the compatibility of thermodynamic database in the multi-component systems,while Bi3Ni was treated as a stoichiometric compound.Finally,a set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phases in this binary system were obtained.The calculated results are in reasonable agreement with the reported experimental data.展开更多
We present a detailed analysis of a double-lined spectroscopic binary system,Bo Gem,using data obtained from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST)and the Transiting Exoplanet Survey Sat...We present a detailed analysis of a double-lined spectroscopic binary system,Bo Gem,using data obtained from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST)and the Transiting Exoplanet Survey Satellite(TESS).By applying spectral disentangling techniques to the LAMOST Medium Resolution Spectra,we determine the orbital parameters,including the orbital period of P=4.0689 days,and semimajor axis of a=14.90±0.04 R_(⊙).The mass ratio between the two components is found to be q=0.198±0.006,with an inclination of i=82°.3±0°.13.The photometric data from TESS revealed periodic light variations due to the eclipsing nature of the system,allowing for the determination of the primary star’s radius as R_(1)=1.68±0.03 R_(⊙)and the secondary star’s radius as R_(2)=3.68±0.04 R_(⊙).The effective temperatures of the primary and secondary stars are measured to be T_(eff,1)=9705±50 K and T_(eff,2)=5830±22 K,respectively.By analyzing the disentangled spectra,we determined the stellar atmospheric parameters—including surface gravity and metallicity of both stars.These results not only confirm the double-lined spectroscopic binary status of Bo Gem,but also underscore its value as an important system for testing and refining stellar evolution models.展开更多
Al-Wardat's method is used in this research to analyze the two components of the HD 25811 binary system,which combines the results of speckle interferometry with the astrometric data to construct the synthetic spe...Al-Wardat's method is used in this research to analyze the two components of the HD 25811 binary system,which combines the results of speckle interferometry with the astrometric data to construct the synthetic spectral energy distribution of the system.The method results in the effective temperatures at 7100±50 K for component A and 7000±50 K for component B,while their masses measure as 1.65±0.15M_(⊙)for component A and1.58±0.14M_(⊙)for component B.The system exists at an estimated age of 0.794 Gyr,while both stars remain in their initial subgiant evolutionary phase.The evolutionary tracks together with isochrones for Z=0.03 validate that the system components share both their origin and chemical compositions.The orbital analysis shows that the system has a period of 15.97 yr and an eccentricity of 0.713,while the total system mass amounts to3.65±0.49 M_(⊙).We detailedly analyze the system's orbital dynamics to assess planetary stability and habitability zones,which lead to the dynamics of circumbinary(P-type)and circumstellar(S-type)orbits using empirical criteria,revealing large regions in which planetary orbits remain dynamically stable.Luminosities and effective temperatures of each stellar component are used to determine their habitable zones.展开更多
We presented the first photometric light curve solutions of four W Ursae Majoris-type contact binary systems.This investigation utilized photometric data from the Transiting Exoplanet Survey Satellite and Gaia Data Re...We presented the first photometric light curve solutions of four W Ursae Majoris-type contact binary systems.This investigation utilized photometric data from the Transiting Exoplanet Survey Satellite and Gaia Data Release 3(DR3).We used the PHysics Of Eclipsing BinariEs Python code and the Markov Chain Monte Carlo method for these light curve solutions.Only TIC 249064185 among the target systems needed a cold starspot to be included in the analysis.Based on the estimated mass ratios for these total eclipse systems,three of them are categorized as low mass ratio contact binary stars.The absolute parameters of the systems were estimated using the Gaia DR3 parallax method and the orbital period and semimajor axis(P-a)empirical relationship.We ascertained that the TIC 318015356 and TIC 55522736 systems are A-subtypes,while TIC 249064185 and TIC 397984843 are W-subtypes,depending on each component’s effective temperature and mass.We estimated the initial masses of the stars,the mass lost by the binary system,and the systems’ages.We displayed star positions in the mass-radius,mass-luminosity,and total mass-orbital angular momentum diagrams.In addition,our findings indicate a good agreement with the mass-temperature empirical parameter relationship for the primary stars.展开更多
AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the dise...AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the disentangled spectra,in order to determine their atmospheric parameters and elemental abundances.The effective temperature and microturbulence(determined from the equivalent widths of Fe II lines)turned out to be(11,150 K,0.9 km s^(-1))and(10,650 K,0.1 km s^(-1))for A and B,respectively.The chemical abundances of 28 elements were then derived while taking into account the non-LTE effect for Z≤15 elements(Z:atomic number).The following trends were elucidated for[X/H](abundance of X relative to the Sun):(1)Qualitatively,[X/H]shows a rough global tendency to increase with Z,with the gradient steeper for A than for B.(2)However,considerable dispersion is involved for A,since prominently large peculiarities are seen in specific elements reflecting the characteristics of HgMn stars(e.g.,very deficient N,Al,Sc,Ni;markedly overabundant P,Mn).(3)In contrast,the Z-dependence of[X/H]for B tends to be nearly linear with only a small dispersion.These observational facts may serve as a key to understanding the critical condition for the emergence of the chemical anomaly.展开更多
Most massive stars reside in binary or multi-object systems.Short gamma-ray bursts(sGRBs),the product of the merger of double compact objects,may originate from massive common-envelope binaries.In contrast,the progeni...Most massive stars reside in binary or multi-object systems.Short gamma-ray bursts(sGRBs),the product of the merger of double compact objects,may originate from massive common-envelope binaries.In contrast,the progenitors of long GRBs(lGRBs)are typically considered isolated massive stars.However,no effective method has yet been established to identify potential companions from current observations.Recent studies have demonstrated that quasi-periodic oscillation signatures can serve as a promising tool to probe the properties of GRB central engines.In this study,by drawing an analogy to periodicity in X-ray binaries,we explore the precession periods of companion-induced disk precession for lGRBs born in the ultra-compact binary scenario.Our results suggest that the periodicity observed in lGRB afterglows,measured in units of 1000 s or more,may indicate that lGRBs originate within binary systems.GRB 050904 could represent a rare case where the burst occurred in a binary system,leaving behind a black hole–black hole binary at redshift z=6.29.展开更多
In this study, the constant volume, visual method is used to measure the critical point of CO2+toluene, CO2+cyclohexane, CO2+n-butyraldehyde, CO2+i-butyraldehyde, CO2+methanol and CO2+alcohol binary systems. The relat...In this study, the constant volume, visual method is used to measure the critical point of CO2+toluene, CO2+cyclohexane, CO2+n-butyraldehyde, CO2+i-butyraldehyde, CO2+methanol and CO2+alcohol binary systems. The relationship between critical point and the concentration of the entrainer for different substances has been discussed, and the comparison of the phase behavior of single component system and that of binary systems have been carried out.展开更多
The vapor-liquid equilibrium (VLE) data for the dimethyl carbonate-n-butyl acetate binary system were measured by an Ellis equilibrated distillator. The experimental data were checked for their thermodynamic consisten...The vapor-liquid equilibrium (VLE) data for the dimethyl carbonate-n-butyl acetate binary system were measured by an Ellis equilibrated distillator. The experimental data were checked for their thermodynamic consistency through statistical methods. The VLE data was correlated with Wilson and NRTL activity coefficient models and also with the calculation of the vapor phase fugacity coefficient by the modified Peng-Robinson equation of state.展开更多
In order to obtain the thermodynamic description of the Mg-Ga binary system,the thermodynamic assessment of the system was carried out using the CALPHAD method through Thermo-calc software package based on the evaluat...In order to obtain the thermodynamic description of the Mg-Ga binary system,the thermodynamic assessment of the system was carried out using the CALPHAD method through Thermo-calc software package based on the evaluation of all available experimental data from the published literature.The solution phases,including liquid,hcp(Mg) and orthorhombic(Ga),were described by the substitutional solution model,of which the excess Gibbs energies were expressed with the Redlich-Kister polynomial.Meanwhile,all intermetallic compounds,Mg5Ga2,Mg2Ga,MgGa,MgGa2 and Mg2Ga5,were modeled as stoichiometric compounds.A set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phases in the Mg-Ga binary system were obtained finally.The much better agreement is achieved between the calculated results and the reported experimental data.展开更多
The Ni-Sb binary alloy system was thermodynamically assessed using CALPHAD approach in this article. Excess Gibbs energies of solution phases, liquid and fcc phases, were formulated using the Redlich-Kister expression...The Ni-Sb binary alloy system was thermodynamically assessed using CALPHAD approach in this article. Excess Gibbs energies of solution phases, liquid and fcc phases, were formulated using the Redlich-Kister expression. The intermediate phases were modeled by the sublattice model with （Ni,Va）0.5（Ni,Sb）0.25（Ni）0.25 for Ni3Sb_HT phase and （Ni,Va）0.3333（Sb）0.3333（Ni,Va）0.3333 for NiSb phase. The other phases including Ni3Sb, Ni7Sb3, and NiSb2 were treated as stoichiometric compound owing to their narrow composition ranges. Based on the reported thermodynamic properties and phase diagram data, the thermodynamic parameters of these phases were optimized, and the obtained values can reproduce the available experimental data well.展开更多
The Bi-Mg binary system had been assessed by adopting the ionic melt and the modified quasi-chemical models to describe the liquid phase with short range ordering behavior. In general considerations of the development...The Bi-Mg binary system had been assessed by adopting the ionic melt and the modified quasi-chemical models to describe the liquid phase with short range ordering behavior. In general considerations of the development of the thermodynamic database of the multi-component Mg-based alloys and the consistency of the thermodynamic models of the related phases, the Gibbs energy descriptions of all the phases in the Bi-Mg binary system were reasonably re-modeled and critically re-assessed in the present work. Especially for the liquid phase, the associate model was used with the constituent species Bi, Mg and Bi2Mg3. The Mg-rich terminal phase hcp_A3 was modeled as a substitutional solution following Redlich-Kister equation and the Bi-rich terminal phase Rhombohedral_A7 was treated as a pure Bi substance since the extremely small solubility of Mg in Bi. The low and high temperature non- stoichiometric compounds β-Bi2Mg3 and α-Bi2Mg3 were described by the sublattice models （Bi,Va）2Mg3 and （Bi）1（Bi,Va）3Mg6 respectively based on their structure features. A set of self-consistent thermodynamic parameters of the Bi-Mg system was obtained and the experimental thermodynamic and phase equilibrium data were well reproduced by the optimized thermodynamic data.展开更多
The thermodynamical properties of MgCl_2 in KCI-MgCl_2-LiCl molten electrolytes containing MgCl_2 below 0.5 (mole fraction, the same below) have been determined from the interchange energies of two binary systems KCI...The thermodynamical properties of MgCl_2 in KCI-MgCl_2-LiCl molten electrolytes containing MgCl_2 below 0.5 (mole fraction, the same below) have been determined from the interchange energies of two binary systems KCI-MgCl_2 and LiCI-MgCl_2, by means of a model on the assumptions that the electrolytes in the solution are treated as independent particles instead of their ion forms and the interchange energy between the component pair KCI-LiCl is ignored when compared with those of component pairs KCl-MgCl_2 and MgCl_2-LiCl. The interchange energies, wKCl-MgCl_2 and wMgcCl_2-Licl, are obtained as-70000 and -13800 J.mol-1, from the corresponding binary solutions, respectively.展开更多
The Ge-La binary system was critically assessed by means of the calculation of phase diagram （CALPHAD） technique. The asso- ciate model was used for the liquid phase containing the constituent species Ge, La, Ge3La5...The Ge-La binary system was critically assessed by means of the calculation of phase diagram （CALPHAD） technique. The asso- ciate model was used for the liquid phase containing the constituent species Ge, La, Ge3La5, and Ge1.7La. The terminal solid solution diamond-（Ge） with a small solubility of La was described using the substitutional model, in which the excess Gibbs energy was formulated with the Redlich-Kister equation. The compounds with homogeneity ranges, μ（Gel.7La）, β（Ge1.7La）, and （GeLa）, were modeled using two sublatrices asα（Ge,La）l.7La, β（Ge,La）l.7La, and （Ge,La）（Ge,La）, respectively. The intermediate phases with no solubility ranges, Ge4Las, GeaLa4, Ge3Las, and GeLa3, were treated as stoichiometric compounds. The three allotropic modifications of La, dhcp-La, fcc-La, and bcc-La, were kept as pure element phases since no solubility of Ge in La was reported. A set of self-consistent thermodynamic parameters of the Ge-La binary system was obtained. The calculation results agree well with the available experimental data from literatures.展开更多
The motion of the moonlet Dactyl in the binary system 243 Ida is investigated in this paper. First, periodic orbits in the vicinity of the primary are calculated, including the orbits around the equilibrium points and...The motion of the moonlet Dactyl in the binary system 243 Ida is investigated in this paper. First, periodic orbits in the vicinity of the primary are calculated, including the orbits around the equilibrium points and large-scale orbits. The Floquet multipliers’ topological cases of periodic orbits are calculated to study the orbits’ stabilities. During the continuation of the retrograde near-circular orbits near the equatorial plane, two period-doubling bifurcations and one Neimark–Sacker bifurcation occur one by one, leading to two stable regions and two unstable regions. Bifurcations occur at the boundaries of these regions. Periodic orbits in the stable regions are all stable, but in the unstable regions are all unstable. Moreover, many quasi-periodic orbits exist near the equatorial plane. Long-term integration indicates that a particle in a quasi-periodic orbit runs in a space like a tire. Quasi-periodic orbits in different regions have different styles of motion indicated by the Poincare sections. There is the possibility that moonlet Dactyl is in a quasi-periodic orbit near the stable region I, which is enlightening for the stability of the binary system.展开更多
In the present paper, the problem of sidebranches in the binary dendritic growth with enforced flow is studied. The positions of the first sidebranch and spacing of dendritic sidebranches are presented. For the neutra...In the present paper, the problem of sidebranches in the binary dendritic growth with enforced flow is studied. The positions of the first sidebranch and spacing of dendritic sidebranches are presented. For the neutral stable mode of dendritic growth, effects of various parameters on sidebranches are analysed. Our result shows that sidebranches are produced behind a critical point ξC′.展开更多
A new expression of mixing rule is suggested according to the Mayson′s mixing rule in this paper, which adopts the Redlich Kwong cubic equation of state and the modified Chueh Prausnitz method to calculate the expe...A new expression of mixing rule is suggested according to the Mayson′s mixing rule in this paper, which adopts the Redlich Kwong cubic equation of state and the modified Chueh Prausnitz method to calculate the experiment critical points of six binary mixtures CO 2+toluene, CO 2+cyclohexane, CO 2+ n butanal, CO 2+ i butanal , CO 2+methanol, CO 2+ethanol. The coefficients of interaction parameter in the expression of mixing rule were optimized from experimental data. The calculated results of critical temperature and critical pressure meet the experiment data well. The maximum relative errors of temperature and pressure between the calculation results and experiment data are 1 493% and 5 2236% respectively, indicating that the proposed expression of mixing rule is reasonable. This may provide a fundamental method for studying and predicting the properties of supercritical fluids.展开更多
The critical curves for binary systems of methane combined with nitrogen, carbon monoxide, carbon dioxide, ethane, propane, butane and water at temperatures from 125 K to 650 K and pressures from 3.5 MPa to 250 MPa we...The critical curves for binary systems of methane combined with nitrogen, carbon monoxide, carbon dioxide, ethane, propane, butane and water at temperatures from 125 K to 650 K and pressures from 3.5 MPa to 250 MPa were calculated by using Heilig-Franck equation of state. This equation of state contains a repulsion term and an attraction term for intermolecular interaction. With pairwise combination rules for these potentials, three adjustable parameters are needed. The results showed that the critical curves of the former six binary systems belonged to type I, and CH4＋H2O system belonged to type III. The calculated data were compared with the experimental data,which yielded good results for the pressure-temperature, pressure-composition and temperature-composition behaviors of the seven systems. Moreover, the values of the adjustable parameters were obtained from the calculation of the critical curves. They can also be used for other relevant calculation.展开更多
By use of micro-DTA technique as well as ambient and high temperature X-ray analysis the phase diagram of NaCl-CaCl_2 has been checked.It is.a simple eutectic system with a solid solubility in the sodium chloride side...By use of micro-DTA technique as well as ambient and high temperature X-ray analysis the phase diagram of NaCl-CaCl_2 has been checked.It is.a simple eutectic system with a solid solubility in the sodium chloride side.The eutectic point is at 773K,49 mol% NaCl.The experimental results,especially those of the X-ray diffraction studies have showed that the incongruent compound 4NaCl-CaCl_2 does not exist in the NaCl-CaCl_2 system.展开更多
In this work, the COSMO-RS （conductor like screening model for real solvent） model algorithm was derived from the modified Rachford rice method. It could be more helpful to investigate the phase behavior of binary s...In this work, the COSMO-RS （conductor like screening model for real solvent） model algorithm was derived from the modified Rachford rice method. It could be more helpful to investigate the phase behavior of binary systems with the help of quantum chemical calculation at 6-31G＊ basis set. COSMO-RS was used to predict solubility of binary mixture involving non-ILs （ionic liquids）, and ILs systems are： benzyl ethylamine ＋ glycerol system （Type-Ⅰ）, nitro methane ＋ cyclohexane system （Type-Ⅱ）, dipropylamine ＋ water system （Type-Ⅲ）, 1,2-ethanediol ＋ thiophene system （Type-Ⅳ）, [1,2-DMIM] [salicylate] ＋ thiophene （Type-Ⅳ）, and [EMIM] [NO3] ＋ thiophene （Type-Ⅳ）. Totally 15 cations with 27 anions were used for generating 405 binary LLE （liquid liquid equilibrium） systems involving thiophene. However, the predicted COSMO-RS values are consisting with the reported experimental values. Furthermore, the immiscibility gap at 298.15 K was determined and compared for various ILs. It was found that l-butylpyrrolidinium, l-octylquinolinium, 1-octylpyridinium and 1-octyl-3-methylimidazolium based cations are most suitable for thiophene extraction from any liquid mixture.展开更多
Photometric observations of an eclipsing binary system, YY Eridani were done in blue (B) and yellow (V) wavelength bands and, finally, the light curve in each wavelength band was constructed. Orbital elements and phys...Photometric observations of an eclipsing binary system, YY Eridani were done in blue (B) and yellow (V) wavelength bands and, finally, the light curve in each wavelength band was constructed. Orbital elements and physical properties of YY Eridani have been calculated using observational data of Binnendijk (1965) and authors have developed Wilson Devinney technique in analyzing the best solution of this eclipsing binary system. More physical parameters eg: orbital inclination, gravity darkening exponent, effective temperature, gravitational potential etc. of each component were calculated in this research for the best solution of YY Eridani. Synthetic light curves which were constructed from the best solution are in good correspondence with observational light curves of Binnendijk. When comparing with observational light curves obtained from this research, it was found that there exist the phase shift of 0 1. It is possible that physical properties of YY Eridani have been changed due to the rotation of its major axis or mass transfer mechanism of the system.展开更多
基金Projects(50371104,50771106and50731002)supported by the National Natural Science Foundation of ChinaProject(2008K22)supported by the Scientific Research Foundation of Hunan Provincial Department of Land&Resources,ChinaProject supported by Geology Exploration Foundation of Hunan Provincial Department of Land&Resources,China
文摘Based on the available experimental data,the Bi-Ni binary system was optimized thermodynamically by the CALPHAD method.The solution phases,including liquid,fcc_A1（Ni） and rhombohedral_A7（Bi）,were described as substitutional solution phases,of which the excess Gibbs energies were expressed with the Redlich-Kister polynomial.The intermetallic compound,BiNi,was modeled using three sublattices（Bi）（Ni,Va）（Ni,Va） considering its crystal structure（NiAs-type） and the compatibility of thermodynamic database in the multi-component systems,while Bi3Ni was treated as a stoichiometric compound.Finally,a set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phases in this binary system were obtained.The calculated results are in reasonable agreement with the reported experimental data.
基金supported by the National Key R&D Program of China for the Intergovernmental Scientific and Technological Innovation Cooperation Project under No.2022YFE0126200Tianshan Talent Training Program under No.2023TSYCLJ0053+3 种基金supported by the National Natural Science Foundation of China under grant Nos.12090040/4,12022304,11973052,11973042,U1931102,12373036the National Key R&D Program of China No.2019YFA0405502support from the Guo Shou Jing TelescopeGuo Shou Jing Telescope(the Large Sky Area Multi-Object Fiber Spectroscopic Telescope LAMOST)is a National Major Scientific Project built by the Chinese Academy of Sciences.Funding for the project has been provided by the National Development and Reform Commission.
文摘We present a detailed analysis of a double-lined spectroscopic binary system,Bo Gem,using data obtained from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST)and the Transiting Exoplanet Survey Satellite(TESS).By applying spectral disentangling techniques to the LAMOST Medium Resolution Spectra,we determine the orbital parameters,including the orbital period of P=4.0689 days,and semimajor axis of a=14.90±0.04 R_(⊙).The mass ratio between the two components is found to be q=0.198±0.006,with an inclination of i=82°.3±0°.13.The photometric data from TESS revealed periodic light variations due to the eclipsing nature of the system,allowing for the determination of the primary star’s radius as R_(1)=1.68±0.03 R_(⊙)and the secondary star’s radius as R_(2)=3.68±0.04 R_(⊙).The effective temperatures of the primary and secondary stars are measured to be T_(eff,1)=9705±50 K and T_(eff,2)=5830±22 K,respectively.By analyzing the disentangled spectra,we determined the stellar atmospheric parameters—including surface gravity and metallicity of both stars.These results not only confirm the double-lined spectroscopic binary status of Bo Gem,but also underscore its value as an important system for testing and refining stellar evolution models.
文摘Al-Wardat's method is used in this research to analyze the two components of the HD 25811 binary system,which combines the results of speckle interferometry with the astrometric data to construct the synthetic spectral energy distribution of the system.The method results in the effective temperatures at 7100±50 K for component A and 7000±50 K for component B,while their masses measure as 1.65±0.15M_(⊙)for component A and1.58±0.14M_(⊙)for component B.The system exists at an estimated age of 0.794 Gyr,while both stars remain in their initial subgiant evolutionary phase.The evolutionary tracks together with isochrones for Z=0.03 validate that the system components share both their origin and chemical compositions.The orbital analysis shows that the system has a period of 15.97 yr and an eccentricity of 0.713,while the total system mass amounts to3.65±0.49 M_(⊙).We detailedly analyze the system's orbital dynamics to assess planetary stability and habitability zones,which lead to the dynamics of circumbinary(P-type)and circumstellar(S-type)orbits using empirical criteria,revealing large regions in which planetary orbits remain dynamically stable.Luminosities and effective temperatures of each stellar component are used to determine their habitable zones.
基金founded by the Gordon and Betty Moore Foundation through grants GBMF5490 and GBMF10501 to Ohio State Universitythe Alfred P.Sloan Foundation grant G-2021-14192
文摘We presented the first photometric light curve solutions of four W Ursae Majoris-type contact binary systems.This investigation utilized photometric data from the Transiting Exoplanet Survey Satellite and Gaia Data Release 3(DR3).We used the PHysics Of Eclipsing BinariEs Python code and the Markov Chain Monte Carlo method for these light curve solutions.Only TIC 249064185 among the target systems needed a cold starspot to be included in the analysis.Based on the estimated mass ratios for these total eclipse systems,three of them are categorized as low mass ratio contact binary stars.The absolute parameters of the systems were estimated using the Gaia DR3 parallax method and the orbital period and semimajor axis(P-a)empirical relationship.We ascertained that the TIC 318015356 and TIC 55522736 systems are A-subtypes,while TIC 249064185 and TIC 397984843 are W-subtypes,depending on each component’s effective temperature and mass.We estimated the initial masses of the stars,the mass lost by the binary system,and the systems’ages.We displayed star positions in the mass-radius,mass-luminosity,and total mass-orbital angular momentum diagrams.In addition,our findings indicate a good agreement with the mass-temperature empirical parameter relationship for the primary stars.
文摘AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the disentangled spectra,in order to determine their atmospheric parameters and elemental abundances.The effective temperature and microturbulence(determined from the equivalent widths of Fe II lines)turned out to be(11,150 K,0.9 km s^(-1))and(10,650 K,0.1 km s^(-1))for A and B,respectively.The chemical abundances of 28 elements were then derived while taking into account the non-LTE effect for Z≤15 elements(Z:atomic number).The following trends were elucidated for[X/H](abundance of X relative to the Sun):(1)Qualitatively,[X/H]shows a rough global tendency to increase with Z,with the gradient steeper for A than for B.(2)However,considerable dispersion is involved for A,since prominently large peculiarities are seen in specific elements reflecting the characteristics of HgMn stars(e.g.,very deficient N,Al,Sc,Ni;markedly overabundant P,Mn).(3)In contrast,the Z-dependence of[X/H]for B tends to be nearly linear with only a small dispersion.These observational facts may serve as a key to understanding the critical condition for the emergence of the chemical anomaly.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDB0550400)the National Key Research and Development Program of China(Nos.2024YFA1611704 and 2021YFA0718500)the National Natural Science Foundation of China(NSFC,Nos.12473049,12041301,12121003,and 12225305).
文摘Most massive stars reside in binary or multi-object systems.Short gamma-ray bursts(sGRBs),the product of the merger of double compact objects,may originate from massive common-envelope binaries.In contrast,the progenitors of long GRBs(lGRBs)are typically considered isolated massive stars.However,no effective method has yet been established to identify potential companions from current observations.Recent studies have demonstrated that quasi-periodic oscillation signatures can serve as a promising tool to probe the properties of GRB central engines.In this study,by drawing an analogy to periodicity in X-ray binaries,we explore the precession periods of companion-induced disk precession for lGRBs born in the ultra-compact binary scenario.Our results suggest that the periodicity observed in lGRB afterglows,measured in units of 1000 s or more,may indicate that lGRBs originate within binary systems.GRB 050904 could represent a rare case where the burst occurred in a binary system,leaving behind a black hole–black hole binary at redshift z=6.29.
基金This work was supported by the National Natural Science Foundation of Chinathe Research Fund for the Doctoral Program of Higher Education(20076004,2000001005).
文摘In this study, the constant volume, visual method is used to measure the critical point of CO2+toluene, CO2+cyclohexane, CO2+n-butyraldehyde, CO2+i-butyraldehyde, CO2+methanol and CO2+alcohol binary systems. The relationship between critical point and the concentration of the entrainer for different substances has been discussed, and the comparison of the phase behavior of single component system and that of binary systems have been carried out.
基金Supported by the China Petrochemical Corporation.
文摘The vapor-liquid equilibrium (VLE) data for the dimethyl carbonate-n-butyl acetate binary system were measured by an Ellis equilibrated distillator. The experimental data were checked for their thermodynamic consistency through statistical methods. The VLE data was correlated with Wilson and NRTL activity coefficient models and also with the calculation of the vapor phase fugacity coefficient by the modified Peng-Robinson equation of state.
基金Project supported by Scientific Research Foundation for Advanced Talents in Central South University of Forestry and Technology,ChinaProject(50731002) supported by the National Natural Science Foundation of China
文摘In order to obtain the thermodynamic description of the Mg-Ga binary system,the thermodynamic assessment of the system was carried out using the CALPHAD method through Thermo-calc software package based on the evaluation of all available experimental data from the published literature.The solution phases,including liquid,hcp(Mg) and orthorhombic(Ga),were described by the substitutional solution model,of which the excess Gibbs energies were expressed with the Redlich-Kister polynomial.Meanwhile,all intermetallic compounds,Mg5Ga2,Mg2Ga,MgGa,MgGa2 and Mg2Ga5,were modeled as stoichiometric compounds.A set of self-consistent thermodynamic parameters formulating the Gibbs energies of various phases in the Mg-Ga binary system were obtained finally.The much better agreement is achieved between the calculated results and the reported experimental data.
基金the National Natu-ral Science Foundation of China (Nos. 50601001 and 50771105)
文摘The Ni-Sb binary alloy system was thermodynamically assessed using CALPHAD approach in this article. Excess Gibbs energies of solution phases, liquid and fcc phases, were formulated using the Redlich-Kister expression. The intermediate phases were modeled by the sublattice model with （Ni,Va）0.5（Ni,Sb）0.25（Ni）0.25 for Ni3Sb_HT phase and （Ni,Va）0.3333（Sb）0.3333（Ni,Va）0.3333 for NiSb phase. The other phases including Ni3Sb, Ni7Sb3, and NiSb2 were treated as stoichiometric compound owing to their narrow composition ranges. Based on the reported thermodynamic properties and phase diagram data, the thermodynamic parameters of these phases were optimized, and the obtained values can reproduce the available experimental data well.
基金supported by the National Natural Science Foundation of China(Nos. 50731002 and 50671009)
文摘The Bi-Mg binary system had been assessed by adopting the ionic melt and the modified quasi-chemical models to describe the liquid phase with short range ordering behavior. In general considerations of the development of the thermodynamic database of the multi-component Mg-based alloys and the consistency of the thermodynamic models of the related phases, the Gibbs energy descriptions of all the phases in the Bi-Mg binary system were reasonably re-modeled and critically re-assessed in the present work. Especially for the liquid phase, the associate model was used with the constituent species Bi, Mg and Bi2Mg3. The Mg-rich terminal phase hcp_A3 was modeled as a substitutional solution following Redlich-Kister equation and the Bi-rich terminal phase Rhombohedral_A7 was treated as a pure Bi substance since the extremely small solubility of Mg in Bi. The low and high temperature non- stoichiometric compounds β-Bi2Mg3 and α-Bi2Mg3 were described by the sublattice models （Bi,Va）2Mg3 and （Bi）1（Bi,Va）3Mg6 respectively based on their structure features. A set of self-consistent thermodynamic parameters of the Bi-Mg system was obtained and the experimental thermodynamic and phase equilibrium data were well reproduced by the optimized thermodynamic data.
基金National Natural Science Foundation of China!No.59774028
文摘The thermodynamical properties of MgCl_2 in KCI-MgCl_2-LiCl molten electrolytes containing MgCl_2 below 0.5 (mole fraction, the same below) have been determined from the interchange energies of two binary systems KCI-MgCl_2 and LiCI-MgCl_2, by means of a model on the assumptions that the electrolytes in the solution are treated as independent particles instead of their ion forms and the interchange energy between the component pair KCI-LiCl is ignored when compared with those of component pairs KCl-MgCl_2 and MgCl_2-LiCl. The interchange energies, wKCl-MgCl_2 and wMgcCl_2-Licl, are obtained as-70000 and -13800 J.mol-1, from the corresponding binary solutions, respectively.
基金supported by the National Natural Science Foundation of China (Nos.50731002 and 50671009)
文摘The Ge-La binary system was critically assessed by means of the calculation of phase diagram （CALPHAD） technique. The asso- ciate model was used for the liquid phase containing the constituent species Ge, La, Ge3La5, and Ge1.7La. The terminal solid solution diamond-（Ge） with a small solubility of La was described using the substitutional model, in which the excess Gibbs energy was formulated with the Redlich-Kister equation. The compounds with homogeneity ranges, μ（Gel.7La）, β（Ge1.7La）, and （GeLa）, were modeled using two sublatrices asα（Ge,La）l.7La, β（Ge,La）l.7La, and （Ge,La）（Ge,La）, respectively. The intermediate phases with no solubility ranges, Ge4Las, GeaLa4, Ge3Las, and GeLa3, were treated as stoichiometric compounds. The three allotropic modifications of La, dhcp-La, fcc-La, and bcc-La, were kept as pure element phases since no solubility of Ge in La was reported. A set of self-consistent thermodynamic parameters of the Ge-La binary system was obtained. The calculation results agree well with the available experimental data from literatures.
基金supported by the National Natural Science Foundation of China (Grant 11572166)
文摘The motion of the moonlet Dactyl in the binary system 243 Ida is investigated in this paper. First, periodic orbits in the vicinity of the primary are calculated, including the orbits around the equilibrium points and large-scale orbits. The Floquet multipliers’ topological cases of periodic orbits are calculated to study the orbits’ stabilities. During the continuation of the retrograde near-circular orbits near the equatorial plane, two period-doubling bifurcations and one Neimark–Sacker bifurcation occur one by one, leading to two stable regions and two unstable regions. Bifurcations occur at the boundaries of these regions. Periodic orbits in the stable regions are all stable, but in the unstable regions are all unstable. Moreover, many quasi-periodic orbits exist near the equatorial plane. Long-term integration indicates that a particle in a quasi-periodic orbit runs in a space like a tire. Quasi-periodic orbits in different regions have different styles of motion indicated by the Poincare sections. There is the possibility that moonlet Dactyl is in a quasi-periodic orbit near the stable region I, which is enlightening for the stability of the binary system.
基金Project supported by the High Technology Research and Development Programme of China (Grant No. 2007AA03Z108)
文摘In the present paper, the problem of sidebranches in the binary dendritic growth with enforced flow is studied. The positions of the first sidebranch and spacing of dendritic sidebranches are presented. For the neutral stable mode of dendritic growth, effects of various parameters on sidebranches are analysed. Our result shows that sidebranches are produced behind a critical point ξC′.
基金Supported by the National Natural Science Foundation of China(No.2 0 0 76 0 0 4 ) and the Research Fund for the Doctor-al Pragram of Higher Education(No.2 0 0 0 0 0 10 0 5 )
文摘A new expression of mixing rule is suggested according to the Mayson′s mixing rule in this paper, which adopts the Redlich Kwong cubic equation of state and the modified Chueh Prausnitz method to calculate the experiment critical points of six binary mixtures CO 2+toluene, CO 2+cyclohexane, CO 2+ n butanal, CO 2+ i butanal , CO 2+methanol, CO 2+ethanol. The coefficients of interaction parameter in the expression of mixing rule were optimized from experimental data. The calculated results of critical temperature and critical pressure meet the experiment data well. The maximum relative errors of temperature and pressure between the calculation results and experiment data are 1 493% and 5 2236% respectively, indicating that the proposed expression of mixing rule is reasonable. This may provide a fundamental method for studying and predicting the properties of supercritical fluids.
基金Supported by National Natural Science Foundation of China (No 20476071)
文摘The critical curves for binary systems of methane combined with nitrogen, carbon monoxide, carbon dioxide, ethane, propane, butane and water at temperatures from 125 K to 650 K and pressures from 3.5 MPa to 250 MPa were calculated by using Heilig-Franck equation of state. This equation of state contains a repulsion term and an attraction term for intermolecular interaction. With pairwise combination rules for these potentials, three adjustable parameters are needed. The results showed that the critical curves of the former six binary systems belonged to type I, and CH4＋H2O system belonged to type III. The calculated data were compared with the experimental data,which yielded good results for the pressure-temperature, pressure-composition and temperature-composition behaviors of the seven systems. Moreover, the values of the adjustable parameters were obtained from the calculation of the critical curves. They can also be used for other relevant calculation.
基金Projects Supported by the National Natural Science Fundation of China.
文摘By use of micro-DTA technique as well as ambient and high temperature X-ray analysis the phase diagram of NaCl-CaCl_2 has been checked.It is.a simple eutectic system with a solid solubility in the sodium chloride side.The eutectic point is at 773K,49 mol% NaCl.The experimental results,especially those of the X-ray diffraction studies have showed that the incongruent compound 4NaCl-CaCl_2 does not exist in the NaCl-CaCl_2 system.
文摘In this work, the COSMO-RS （conductor like screening model for real solvent） model algorithm was derived from the modified Rachford rice method. It could be more helpful to investigate the phase behavior of binary systems with the help of quantum chemical calculation at 6-31G＊ basis set. COSMO-RS was used to predict solubility of binary mixture involving non-ILs （ionic liquids）, and ILs systems are： benzyl ethylamine ＋ glycerol system （Type-Ⅰ）, nitro methane ＋ cyclohexane system （Type-Ⅱ）, dipropylamine ＋ water system （Type-Ⅲ）, 1,2-ethanediol ＋ thiophene system （Type-Ⅳ）, [1,2-DMIM] [salicylate] ＋ thiophene （Type-Ⅳ）, and [EMIM] [NO3] ＋ thiophene （Type-Ⅳ）. Totally 15 cations with 27 anions were used for generating 405 binary LLE （liquid liquid equilibrium） systems involving thiophene. However, the predicted COSMO-RS values are consisting with the reported experimental values. Furthermore, the immiscibility gap at 298.15 K was determined and compared for various ILs. It was found that l-butylpyrrolidinium, l-octylquinolinium, 1-octylpyridinium and 1-octyl-3-methylimidazolium based cations are most suitable for thiophene extraction from any liquid mixture.
文摘Photometric observations of an eclipsing binary system, YY Eridani were done in blue (B) and yellow (V) wavelength bands and, finally, the light curve in each wavelength band was constructed. Orbital elements and physical properties of YY Eridani have been calculated using observational data of Binnendijk (1965) and authors have developed Wilson Devinney technique in analyzing the best solution of this eclipsing binary system. More physical parameters eg: orbital inclination, gravity darkening exponent, effective temperature, gravitational potential etc. of each component were calculated in this research for the best solution of YY Eridani. Synthetic light curves which were constructed from the best solution are in good correspondence with observational light curves of Binnendijk. When comparing with observational light curves obtained from this research, it was found that there exist the phase shift of 0 1. It is possible that physical properties of YY Eridani have been changed due to the rotation of its major axis or mass transfer mechanism of the system.
