As the demand for advanced material design and performance prediction continues to grow,traditional phase-field models are increasingly challenged by limitations in computational efficiency and predictive accuracy,par...As the demand for advanced material design and performance prediction continues to grow,traditional phase-field models are increasingly challenged by limitations in computational efficiency and predictive accuracy,particularly when addressing high-dimensional and complex data in multicomponent systems.To overcome these challenges,this study proposes an innovative model,LSGWO-BP,which integrates an improved Grey Wolf Optimizer(GWO)with a backpropagation neural network(BP)to enhance the accuracy and efficiency of quasi-phase equilibrium predictions within the KKS phase-field framework.Three mapping enhancement strategies were investigated–Circle-Root,Tent-Cosine,and Logistic-Sine mappings-with the Logistic mapping further improved via Sine perturbation to boost global search capability and convergence speed in large-scale,complex data scenarios.Evaluation results demonstrate that the LSGWO-BP model significantly outperforms conventional machine learning approaches in predicting quasi-phase equilibrium,achieving a 14%–28%reduction in mean absolute error(MAE).Substantial improvements were also observed in mean squared error,root mean squared error,and mean absolute percentage error,alongside a 7%–33%increase in the coefficient of determination(R2).Furthermore,the model exhibits strong potential for microstructural simulation applications.Overall,the study confirms the effectiveness of the LSGWO-BP model in materials science,especially in enhancing phase-field modeling efficiency and enabling accurate,intelligent prediction for multicomponent alloy systems,thereby offering robust support for microstructure prediction and control.展开更多
Phase equilibrium modeling using internally consistent thermodynamic dataset and associated activity-composition(a-x)models are very helpful for quantifying P-T evolution for eclogite,which is the basis for decipherin...Phase equilibrium modeling using internally consistent thermodynamic dataset and associated activity-composition(a-x)models are very helpful for quantifying P-T evolution for eclogite,which is the basis for deciphering the geodynamic processes in subduction zones.In this study,we apply different versions of datasets(ds55 and ds62)and associated a-x relations to a wellestablished LT-HP eclogite at Huwan in the classic western Dabie orogen to constrain its P-T evolution.The eclogite comprises garnet+omphacite+amphibole+white mica+epidote+quartz+chlorite+rutile/ilmenite/sphene.Garnet porphyroblasts show mono-variation in the end members(spessartine from 17 mol%to 0,pyrope from 2 mol%to 18 mol%,almandine from 47 mol%to 64mol%and grossular from 35 mol%to 18 mol%)from core to rim.Phase diagrams combined with compositional isopleth thermobarometry show that dataset ds62 and associated a-x relations yield P_(max)of~33 kbar at~560℃,conflicting with our petrological observations and previous studies.On the other hand,phase equilibrium modeling using dataset ds62 and a revised symmetric garnet a-x model irrespective of Fe^(3+)(O)gives P_(max)of~27 kbar at~560℃,consistent with the results using dataset ds55 and associated a-x relations.Therefore,we recommend a symmetric model for garnet involving py,alm,gr and spss,without Fe~(3+)components,instead of the asymmetric garnet a-x relations involving py,alm,gr,spss and kho by White et al.(2014),for calculating phase diagrams for LT-(U)HP eclogite when using dataset ds62.In this study,the defined P-T path is characterized by a segment of the prograde evolution showing a first moderate slope,followed by gentle then steep slopes,representing the thermal structure evolution recorded by slab surface during continental subduction.Our work combined with previous studies conclude that in western Dabie,the Huwan HP eclogite belt to the north and the Hong'an HP eclogite belt to the south belong to the same HP slice overlying the Xinxian UHP slice.展开更多
Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing exp...Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing experimental phenomena of alloy phase transitions during extremely slow variation in temperature by equilibrium thinking mode and then taking erroneous knowledge of experimental phenomena as selected information for establishing Gibbs energy function and so-called equilibrium phase diagram. Second, the equilibrium holographic network phase diagrams of AuCu3-type sublattice system may be used to describe systematic correlativity of the composition?temperature-dependent alloy gene arranging structures and complete thermodynamic properties, and to be a standard for studying experimental subequilibrium order-disorder transition. Third, the equilibrium transition of each alloy is a homogeneous single-phase rather than a heterogeneous two-phase, and there exists a single-phase boundary curve without two-phase region of the ordered and disordered phases; the composition and temperature of the top point on the phase-boundary curve are far away from the ones of the critical point of the AuCu3 compound.展开更多
Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that...Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that the Gibbs energy function of an alloy phase should be derived from Gibbs energy partition function constructed of alloy gene sequence and their Gibbs energy sequence. Second, the six rules for establishing alloy gene Gibbs energy partition function have been discovered, and it has been specially proved that the probabilities of structure units occupied at the Gibbs energy levels in the degeneracy factor for calculating configuration entropy should be degenerated as ones of component atoms occupied at the lattice points. Third, the main characteristics unexpected by today’s researchers are as follows. There exists a single-phase boundary curve without two-phase region coexisting by the ordered and disordered phases. The composition and temperature of the top point on the phase-boundary curve are far away from those of the critical point of the Au3Cu compound; At 0 K, the composition of the lowest point on the composition-dependent Gibbs energy curve is notably deviated from that of the Au3Cu compounds. The theoretical limit composition range of long range ordered Au3Cu-type alloys is determined by the first jumping order degree.展开更多
In order to provide the theoretical guidance for applying the neutralization method to treatment of heavy metals wastewater with high concentration of sulfate, and to better understand the mechanism of calcium sulfate...In order to provide the theoretical guidance for applying the neutralization method to treatment of heavy metals wastewater with high concentration of sulfate, and to better understand the mechanism of calcium sulfate scale formation, the equilibrium solubility data of CaSOa-Ca（OH）2-H2O system at 298.15 K were theoretically calculated via the Pitzer semi-empirical ion-interaction theory, and determined experimentally by the optical method combining with X-ray diffractometry, and the calculated and determined phase diagrams of CaSOa-Ca（OH）2-H2O system were plotted and compared. Physical definition of each area was studied, and the physical law of characteristic point and line was explained in detail. Adjusting the pH value of neutralization-hydrolysis solution depended on the SO4z- concentration in the system. And interaction characteristics between the solubilities of CaSO4（s）and Ca（OH）2（s）were found out.展开更多
The solubilities and the refractive indices of the saturated solution in the system C 6H 12 O 6 NH 4Cl C 2H 5OH-H 2O ( C 2H 5OH / H 2O=0.90, by wt ) at 35℃ have been determined. The isotherms and r...The solubilities and the refractive indices of the saturated solution in the system C 6H 12 O 6 NH 4Cl C 2H 5OH-H 2O ( C 2H 5OH / H 2O=0.90, by wt ) at 35℃ have been determined. The isotherms and refractive indices of the system at 35℃ consist of 2 branches, corresponding to C 6H 12 O 6( H 2O and NH 4Cl. The composition of eutectic solution is C 6H 12 O 6: 4.40 %, NH 4Cl: 13.86 %, C 2H 5OH: 38.88 %.展开更多
The granulitized eclogites from the Luliangshan terrane of the North Qaidam UHP metamorphic belt occur as lenses within pelitic gneisses and orthogneisses. Combined petrologic data and phase equilibrium modeling indic...The granulitized eclogites from the Luliangshan terrane of the North Qaidam UHP metamorphic belt occur as lenses within pelitic gneisses and orthogneisses. Combined petrologic data and phase equilibrium modeling indicate a multi-stage metamorphic history of the granulitized eclogites:(1) an earlier eclogite facies metamorphism(P>18.5 kbar, T> 830℃) is deduced from omphacite relics in the matrix and rare omphacite inclusions within garnet. The possible assemblage is garnet+omphacite+rutile+ quartz;(2) the early stage of high pressure granulite facies assemblages(garnet+clinopyroxene+ plagioclase+rutile+quartz+liquid) developed in the early decompression process has a P-T regime of 17.5 kbar and 852–858 ℃, constrained by plagioclase and clinopyroxene inclusions in garnet. The late stage of high pressure granulite assemblages(garnet+clinopyroxene+amphibole+plagioclase+rutile+quartz+liquid) records an isothermal decompression process with the pressure successively declining from 17.5 to 14.7 kbar and to 11.3 kbar at 858 ℃;(3) the later medium pressure granulite facies assemblage(garnet+ orthopyroxene+clinopyroxene+amphibole+plagioclase+ilmenite+liquid+quartz) indicates a drop in pressure and rise in temperature at P-T conditions of 7.6–7.7 kbar and 878–883 ℃;(4) retrogressive amphibolite facies stage, which is represented by amphibole+plagioclase kelyphitic rims around garnet, formed under conditions of <5 kbar and <650 ℃. The preservation of medium pressure granulite facies assemblage and the garnet composition feature constrain a following isobaric cooling path during late exhumation. This process suggests a clockwise P-T path and indicates that the granulitized eclogites record a high grade "Barrovian" metamorphic overprint at the middle-lower crust during exhumation. The present data show that the Luliangshan terrane is a "hot" HP-UHP terrane.展开更多
The phase equilibrium data of CO2 hydrocarbon binary mixtures are important for the design and operation of CO 2 ood- ing, coal liquefaction, and supercritical extraction processes. Numerous pieces of binary phase equ...The phase equilibrium data of CO2 hydrocarbon binary mixtures are important for the design and operation of CO 2 ood- ing, coal liquefaction, and supercritical extraction processes. Numerous pieces of binary phase equilibrium data have been obtained. Thus, models for the accurate calculation of binary and multicomponent mixtures must be developed on the basis of existing data. In this work, 3578 vapor liquid phase equilibrium data points for 10 CO 2 hydrocarbon binary mixtures, including CO2 butane, CO 2 pentane, CO 2 isopentane, C O 2 hexane, CO 2 benzene, CO 2 heptane, CO 2 octane, C O 2 non- ane, CO 2 decane, and C O 2 undecane, were collected. The PR and PR-BM equations of state (EOS) in combination with relevant mixing rules were used to calculate the phase equilibrium data of the CO 2 hydrocarbon binary mixtures. The binary interaction parameter k ij in the PR EOS was temperature independent, whereas parameters in the PR-BM EOS were functions of temperature. Thus, the phase equilibrium data and other thermodynamic properties of the binary and multicomponent mixtures at di erent temperatures and pressures can be calculated by using the parameters obtained in this work. The PR-BM EOS performed better than the PR EOS, and the average absolute deviations over the temperature range of 255.98 408.15 K calculated by the PR EOS and PR-BM EOS were less than 5.74% and 3.36%, respectively. The results calculated by the two EOS were compared with those calculated by other models, such as PPR78, PR + LCVM + UNIFAC, KIE + PR EOS + HV, and PSRK. The phase equilibrium data of CO 2 butane decane, CO 2 hexane decane, and C O 2 octane decane ternary mixtures were calculated by the two EOS. The average overall deviations for the CO 2 mole fractions calculated by the two EOS were less than 7.66%.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
a gliding arc driven by the transverse magnetic field was ignited between the electrodes with a complicated shape at atmospheric pressure and a non-equilibrium plasma was gencrated. Under our experimental conditions, ...a gliding arc driven by the transverse magnetic field was ignited between the electrodes with a complicated shape at atmospheric pressure and a non-equilibrium plasma was gencrated. Under our experimental conditions, a phenomenon was clearly observed where the arc power decreased with the increase in arc voltage. As the arc voltage was higher than 3.375 kV, the are power acquired from the power supply decreased, and the arc plasma began to switch to a non-equilibrium phase. The existence of the non-equilibrium arc plasma was very short, about 10 ms in one gliding arc discharge cycle.展开更多
Vapor-liquid phase equilibrium data including composition,densities,molar volume and equilibrium constant of isobutanol in supercritical carbon dioxide from 313.2K to 353.2K were measured in a variable-volume visual c...Vapor-liquid phase equilibrium data including composition,densities,molar volume and equilibrium constant of isobutanol in supercritical carbon dioxide from 313.2K to 353.2K were measured in a variable-volume visual cell.The properties of critical point were obtained by extrapolation.The results showed that critical temperature,critical pressure and critical compressibility factor of CO2-isobutanol system decreased with the increase of critical CO2 content.The phase equilibrium model was established by Peng-Robinson equation of state and van der Waals-2 mixing regulation,and model parameters were determined by optimization calculation of nonlinear least square method.The correlation between calculated values and the experimental data showed good agreement.展开更多
1 Introduction The brines with high concentrations of magnesium and boron resources are widely distributed in the Qaidam Basin of the Qinghai-Tibet plateau,China(Zheng&Tang,1988).Although some works on the ternary...1 Introduction The brines with high concentrations of magnesium and boron resources are widely distributed in the Qaidam Basin of the Qinghai-Tibet plateau,China(Zheng&Tang,1988).Although some works on the ternary system展开更多
Swelling capacity of vinyl chloride (VC) in chlorinated polyethylene (CPE) with 25—40 wt% Cl at temperature 30—57℃ was studied and their relationships were correlated with Langmuir and Freundlich adsorption equatio...Swelling capacity of vinyl chloride (VC) in chlorinated polyethylene (CPE) with 25—40 wt% Cl at temperature 30—57℃ was studied and their relationships were correlated with Langmuir and Freundlich adsorption equations. A ternary phase diagram for VC-CPE-PVC was also established. In-situ polymerization conditions of CPE-g-VC were proposed and CPE content control was analyzed for the manufacturing process of CPE-g-VC graft product based on results of phase equilibrium study.展开更多
This research study aims to enhance the optimization performance of a newly emerged Aquila Optimization algorithm by incorporating chaotic sequences rather than using uniformly generated Gaussian random numbers.This w...This research study aims to enhance the optimization performance of a newly emerged Aquila Optimization algorithm by incorporating chaotic sequences rather than using uniformly generated Gaussian random numbers.This work employs 25 different chaotic maps under the framework of Aquila Optimizer.It considers the ten best chaotic variants for performance evaluation on multidimensional test functions composed of unimodal and multimodal problems,which have yet to be studied in past literature works.It was found that Ikeda chaotic map enhanced Aquila Optimization algorithm yields the best predictions and becomes the leading method in most of the cases.To test the effectivity of this chaotic variant on real-world optimization problems,it is employed on two constrained engineering design problems,and its effectiveness has been verified.Finally,phase equilibrium and semi-empirical parameter estimation problems have been solved by the proposed method,and respective solutions have been compared with those obtained from state-of-art optimizers.It is observed that CH01 can successfully cope with the restrictive nonlinearities and nonconvexities of parameter estimation and phase equilibrium problems,showing the capabilities of yielding minimum prediction error values of no more than 0.05 compared to the remaining algorithms utilized in the performance benchmarking process.展开更多
Efficient capture,safe storage and release of tritium from the international thermonuclear experimental reactor(ITER) reaction exhaust gas is a perplexing problem,and the development of an efficient tritium-getter mat...Efficient capture,safe storage and release of tritium from the international thermonuclear experimental reactor(ITER) reaction exhaust gas is a perplexing problem,and the development of an efficient tritium-getter material with ultra-low hydrogenation equilibrium pressure is considered as a reliable way.In this work,Zr_(2)Co alloy was selected as a tritium-getter material and prepared through induction levitation melting.Fundamental performance test results show that Zr_(2)Co exhibits an ultra-low hydrogenation equilibrium pressure of 3.22 × 10^(-6) Pa at 25℃ and excellent hydriding kinetics under a low hydrogen pressure of 0.005 MPa.Interestingly,unique phase transition behaviors were presented in Zr_(2)Co-H system.Specifically,Zr_(2)CoH_(5) formed by Zr_(2)Co hydrogenated at room temperature is initially decomposed into ZrH_(2) and ZrCoH_(3) at200 ℃.With the temperature increasing to 350 ℃,ZrCoH_(3)is dehydrogenated to ZrCo,and then ZrCo further reacts with ZrH_(2) at 650 ℃ to reform Zr_(2)Co and hydrogen.Among the staged phase transition pathways during dehydrogenation,the decomposition of Zr_(2)CoH_(5) occurs preferentially,which is well accordance with both the smallest reaction energy barrier and the maximum reaction spontaneity that are determined respectively from kinetics activation energy and thermodynamics Gibbs free energy.Furthermore,first principles calculation results indicate that the stronger binding of hydrogen in interstitial environments of ZrCoH_(3)and ZrH_(2) triggers the hydrogen-stabilized phase transformation of Zr_(2)CoH_(5).The unique phase transition mechanisms in Zr_(2)Co-H system can shed light on the further exploration and regulation of analogous staged phase transition of hydrogen storage materials.展开更多
The phase equilibrium information of slag plays an important role in pyrometallurgical processes to obtain optimum fluxing conditions and operating temperatures.The smelting reduction of titanomagnetite and ilmenite o...The phase equilibrium information of slag plays an important role in pyrometallurgical processes to obtain optimum fluxing conditions and operating temperatures.The smelting reduction of titanomagnetite and ilmenite ores in an iron blast furnace(BF)can form Ti(C,N)particles,causing the increased viscosities of slag and hot metal.HIsmelt has been developed in recent years for ironmaking and does not need coke and sinter.The formation of Ti(C,N)in the HIsmelt process is avoided because the oxygen partial pressure in the process is higher than that in the BF.The smelting of TiO_(2)-containing ores in the HIsmelt process results in Al_(2)O_(3)-MgO-SiO_(2)-CaO-TiO_(2)slag.Phase equilibrium in this slag system has been investigated using equilibration,quenching,and electron probe microanalysis techniques.The experimental results were presented in two pseudo-binary sections,which represent the process of HIsmelt for the treatment of 100%titanomagnetite ore and mixed titanomagnetite+ilmenite ore(mass ratio of 2:1),respectively.The primary phases observed in the composition range investigated include pseudo-brookite M_(3)O_(5)(MgO·2TiO_(2)-Al_(2)O_(3)·TiO_(2)),spinel(MgO·Al_(2)O_(3)),perovskite CaTiO_(3),and rutile TiO_(2).The results show that the liquidus temperatures decrease in the TiO_(2)and M_(3)O_(5) primary phase fields and increase in the spinel and CaTiO_(3)primary phase fields with the increase in CaO concentration.The calculation of solid-phase fractions from the experimental data has been demonstrated.The effect of basicity on the liquidus temperatures of the slag has been discussed.The smelting of titanomagnetite plus ilmenite ores has significant advantages to obtain low-sulfur hot metal and high-TiO_(2)slag.Experimentally determined liquidus temperatures were compared with the FactSage predictions to evaluate the existing thermodynamic databases.展开更多
A new non-cubic equation of state is proposed for calculation of the thermodynamic properties ofnonpolar and polar fluids and their mixtures,including,saturated vapor pressure,saturated liquid volume,saturated vapor v...A new non-cubic equation of state is proposed for calculation of the thermodynamic properties ofnonpolar and polar fluids and their mixtures,including,saturated vapor pressure,saturated liquid volume,saturated vapor volume,heats of vaporization and vapor-liquid equilibria.The new equation is derived from thegeneralized van der Waals partition function in which the repulsive terms are expressed with the Carnahan andStarling equation for hard spheres,and the attractive terms are made up of the dispersive energy and theChemical association energy. The rules of dependence of parameters α and σ and on temperature are considered broadly so that the newequation yields good agreement with experimental saturated properties of 20 nonpolar and 27 polar fluids in therange of reduced temperatures of 0.5 to 1.0 The new equation with parameters group-contributed generally givessatisfactory predictions on saturated properties. Correlations of vapor-liquid equilibrium data for alcohol-containing systems by using van展开更多
Here we review a new class of mixing rules (hat have extended range of mixtures and conditions that can now be described by equation of state models. One characteristic of these mixing rules is that they simultaneousl...Here we review a new class of mixing rules (hat have extended range of mixtures and conditions that can now be described by equation of state models. One characteristic of these mixing rules is that they simultaneously satisfy the boundary conditions of producing a second virial coefficient that is quadratic in mole fraction, and a free energy of mixing like that of an activity coefficient model at high density, though the mixing rule is itself independent of density. We show that using this mixing rule, various asymmetric, highly nonideal mixtures can be accurately described. One serendipitous result is that the parameters in this mixing rule model are almost independent of temperature, which allows accurate extrapolations of phase behavior to be made over large ranges of temperature and pressure.展开更多
A flow apparatus was set up for measuring the solubility of a solid solute in a supercritical fluid withthe presence of a small amount of entrainer.The solubilities of biphenyl,diphenylamine and benzoic acid insupercr...A flow apparatus was set up for measuring the solubility of a solid solute in a supercritical fluid withthe presence of a small amount of entrainer.The solubilities of biphenyl,diphenylamine and benzoic acid insupercritical carbon dioxide with one of the selected entrainers which were ethanol,acetone and n-hexanerespectively,were obtained in the pressure range of 10—32 MPa and the temperature range of 308—318K.Asolvolytic association theory has been proposed to explain the mechanism of entrainer effect,and theexperimental results were reasonably analysed.According to the solvolytic association theory,the association equa-tion of state was adopted to correlate the experimental data with good accuracy.展开更多
Alloys of Mg-Zn-La system in Mg rich corner were prepared, and the phase relationship was investigated at different temperatures such as 200, 300 and 350 ℃ by scanning electron microscopy(SEM), X-ray diffraction(XRD)...Alloys of Mg-Zn-La system in Mg rich corner were prepared, and the phase relationship was investigated at different temperatures such as 200, 300 and 350 ℃ by scanning electron microscopy(SEM), X-ray diffraction(XRD) and electron probe microanalysis with energy dispersive X-ray spectroscopy (EPMA). Two types of phase equilibrium were identified at the different temperatures. One is two-phase equilibrium contained the Mg solid solution and T-phase. The other is three-phase equilibrium which contained the Mg solid solution, MgZn phase and T-phase. T-phase was stable as the temperature changed. The La content in T-phase is constant which is about 8±0.3% (atom fraction); but the Mg content and Zn content of that is changed, and the Zn content in T-phase was from 16.1% to 44%. The solubility of La in MgZn phase was increased from 1.2% to 1.6% as the temperature increasing from 200 to 350 ℃.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52161002,51661020 and 11364024)。
文摘As the demand for advanced material design and performance prediction continues to grow,traditional phase-field models are increasingly challenged by limitations in computational efficiency and predictive accuracy,particularly when addressing high-dimensional and complex data in multicomponent systems.To overcome these challenges,this study proposes an innovative model,LSGWO-BP,which integrates an improved Grey Wolf Optimizer(GWO)with a backpropagation neural network(BP)to enhance the accuracy and efficiency of quasi-phase equilibrium predictions within the KKS phase-field framework.Three mapping enhancement strategies were investigated–Circle-Root,Tent-Cosine,and Logistic-Sine mappings-with the Logistic mapping further improved via Sine perturbation to boost global search capability and convergence speed in large-scale,complex data scenarios.Evaluation results demonstrate that the LSGWO-BP model significantly outperforms conventional machine learning approaches in predicting quasi-phase equilibrium,achieving a 14%–28%reduction in mean absolute error(MAE).Substantial improvements were also observed in mean squared error,root mean squared error,and mean absolute percentage error,alongside a 7%–33%increase in the coefficient of determination(R2).Furthermore,the model exhibits strong potential for microstructural simulation applications.Overall,the study confirms the effectiveness of the LSGWO-BP model in materials science,especially in enhancing phase-field modeling efficiency and enabling accurate,intelligent prediction for multicomponent alloy systems,thereby offering robust support for microstructure prediction and control.
基金financially supported by the National Natural Science Foundation of China(No.41930215)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)。
文摘Phase equilibrium modeling using internally consistent thermodynamic dataset and associated activity-composition(a-x)models are very helpful for quantifying P-T evolution for eclogite,which is the basis for deciphering the geodynamic processes in subduction zones.In this study,we apply different versions of datasets(ds55 and ds62)and associated a-x relations to a wellestablished LT-HP eclogite at Huwan in the classic western Dabie orogen to constrain its P-T evolution.The eclogite comprises garnet+omphacite+amphibole+white mica+epidote+quartz+chlorite+rutile/ilmenite/sphene.Garnet porphyroblasts show mono-variation in the end members(spessartine from 17 mol%to 0,pyrope from 2 mol%to 18 mol%,almandine from 47 mol%to 64mol%and grossular from 35 mol%to 18 mol%)from core to rim.Phase diagrams combined with compositional isopleth thermobarometry show that dataset ds62 and associated a-x relations yield P_(max)of~33 kbar at~560℃,conflicting with our petrological observations and previous studies.On the other hand,phase equilibrium modeling using dataset ds62 and a revised symmetric garnet a-x model irrespective of Fe^(3+)(O)gives P_(max)of~27 kbar at~560℃,consistent with the results using dataset ds55 and associated a-x relations.Therefore,we recommend a symmetric model for garnet involving py,alm,gr and spss,without Fe~(3+)components,instead of the asymmetric garnet a-x relations involving py,alm,gr,spss and kho by White et al.(2014),for calculating phase diagrams for LT-(U)HP eclogite when using dataset ds62.In this study,the defined P-T path is characterized by a segment of the prograde evolution showing a first moderate slope,followed by gentle then steep slopes,representing the thermal structure evolution recorded by slab surface during continental subduction.Our work combined with previous studies conclude that in western Dabie,the Huwan HP eclogite belt to the north and the Hong'an HP eclogite belt to the south belong to the same HP slice overlying the Xinxian UHP slice.
基金Project(51071181)supported by the National Natural Science Foundation of ChinaProject(2013FJ4043)supported by the Natural Science Foundation of Hunan Province,China
文摘Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing experimental phenomena of alloy phase transitions during extremely slow variation in temperature by equilibrium thinking mode and then taking erroneous knowledge of experimental phenomena as selected information for establishing Gibbs energy function and so-called equilibrium phase diagram. Second, the equilibrium holographic network phase diagrams of AuCu3-type sublattice system may be used to describe systematic correlativity of the composition?temperature-dependent alloy gene arranging structures and complete thermodynamic properties, and to be a standard for studying experimental subequilibrium order-disorder transition. Third, the equilibrium transition of each alloy is a homogeneous single-phase rather than a heterogeneous two-phase, and there exists a single-phase boundary curve without two-phase region of the ordered and disordered phases; the composition and temperature of the top point on the phase-boundary curve are far away from the ones of the critical point of the AuCu3 compound.
基金Project(51071181)supported by the National Natural Science Foundation of ChinaProject(2013FJ4043)supported by the Natural Science Foundation of Hunan Province,China
文摘Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that the Gibbs energy function of an alloy phase should be derived from Gibbs energy partition function constructed of alloy gene sequence and their Gibbs energy sequence. Second, the six rules for establishing alloy gene Gibbs energy partition function have been discovered, and it has been specially proved that the probabilities of structure units occupied at the Gibbs energy levels in the degeneracy factor for calculating configuration entropy should be degenerated as ones of component atoms occupied at the lattice points. Third, the main characteristics unexpected by today’s researchers are as follows. There exists a single-phase boundary curve without two-phase region coexisting by the ordered and disordered phases. The composition and temperature of the top point on the phase-boundary curve are far away from those of the critical point of the Au3Cu compound; At 0 K, the composition of the lowest point on the composition-dependent Gibbs energy curve is notably deviated from that of the Au3Cu compounds. The theoretical limit composition range of long range ordered Au3Cu-type alloys is determined by the first jumping order degree.
基金Project (50925417) supported by the Funds for Distinguished Young Scientists of ChinaProject (50830301) supported by the National Natural Science Foundation of ChinaProject (2009ZX07212-001-01) supported by Major Science and Technology Program for Water Pollution Control and Treatment
文摘In order to provide the theoretical guidance for applying the neutralization method to treatment of heavy metals wastewater with high concentration of sulfate, and to better understand the mechanism of calcium sulfate scale formation, the equilibrium solubility data of CaSOa-Ca（OH）2-H2O system at 298.15 K were theoretically calculated via the Pitzer semi-empirical ion-interaction theory, and determined experimentally by the optical method combining with X-ray diffractometry, and the calculated and determined phase diagrams of CaSOa-Ca（OH）2-H2O system were plotted and compared. Physical definition of each area was studied, and the physical law of characteristic point and line was explained in detail. Adjusting the pH value of neutralization-hydrolysis solution depended on the SO4z- concentration in the system. And interaction characteristics between the solubilities of CaSO4（s）and Ca（OH）2（s）were found out.
文摘The solubilities and the refractive indices of the saturated solution in the system C 6H 12 O 6 NH 4Cl C 2H 5OH-H 2O ( C 2H 5OH / H 2O=0.90, by wt ) at 35℃ have been determined. The isotherms and refractive indices of the system at 35℃ consist of 2 branches, corresponding to C 6H 12 O 6( H 2O and NH 4Cl. The composition of eutectic solution is C 6H 12 O 6: 4.40 %, NH 4Cl: 13.86 %, C 2H 5OH: 38.88 %.
基金financially supported by the National Natural Science Foundation of China (Nos. 41630207, 41572180)the China Geological Survey (No. DD20160022)
文摘The granulitized eclogites from the Luliangshan terrane of the North Qaidam UHP metamorphic belt occur as lenses within pelitic gneisses and orthogneisses. Combined petrologic data and phase equilibrium modeling indicate a multi-stage metamorphic history of the granulitized eclogites:(1) an earlier eclogite facies metamorphism(P>18.5 kbar, T> 830℃) is deduced from omphacite relics in the matrix and rare omphacite inclusions within garnet. The possible assemblage is garnet+omphacite+rutile+ quartz;(2) the early stage of high pressure granulite facies assemblages(garnet+clinopyroxene+ plagioclase+rutile+quartz+liquid) developed in the early decompression process has a P-T regime of 17.5 kbar and 852–858 ℃, constrained by plagioclase and clinopyroxene inclusions in garnet. The late stage of high pressure granulite assemblages(garnet+clinopyroxene+amphibole+plagioclase+rutile+quartz+liquid) records an isothermal decompression process with the pressure successively declining from 17.5 to 14.7 kbar and to 11.3 kbar at 858 ℃;(3) the later medium pressure granulite facies assemblage(garnet+ orthopyroxene+clinopyroxene+amphibole+plagioclase+ilmenite+liquid+quartz) indicates a drop in pressure and rise in temperature at P-T conditions of 7.6–7.7 kbar and 878–883 ℃;(4) retrogressive amphibolite facies stage, which is represented by amphibole+plagioclase kelyphitic rims around garnet, formed under conditions of <5 kbar and <650 ℃. The preservation of medium pressure granulite facies assemblage and the garnet composition feature constrain a following isobaric cooling path during late exhumation. This process suggests a clockwise P-T path and indicates that the granulitized eclogites record a high grade "Barrovian" metamorphic overprint at the middle-lower crust during exhumation. The present data show that the Luliangshan terrane is a "hot" HP-UHP terrane.
基金supported by the National Key Research and Development Program of China (2016YFB0600804-3)Shandong Natural Science Foundation (ZR2017BB076)
文摘The phase equilibrium data of CO2 hydrocarbon binary mixtures are important for the design and operation of CO 2 ood- ing, coal liquefaction, and supercritical extraction processes. Numerous pieces of binary phase equilibrium data have been obtained. Thus, models for the accurate calculation of binary and multicomponent mixtures must be developed on the basis of existing data. In this work, 3578 vapor liquid phase equilibrium data points for 10 CO 2 hydrocarbon binary mixtures, including CO2 butane, CO 2 pentane, CO 2 isopentane, C O 2 hexane, CO 2 benzene, CO 2 heptane, CO 2 octane, C O 2 non- ane, CO 2 decane, and C O 2 undecane, were collected. The PR and PR-BM equations of state (EOS) in combination with relevant mixing rules were used to calculate the phase equilibrium data of the CO 2 hydrocarbon binary mixtures. The binary interaction parameter k ij in the PR EOS was temperature independent, whereas parameters in the PR-BM EOS were functions of temperature. Thus, the phase equilibrium data and other thermodynamic properties of the binary and multicomponent mixtures at di erent temperatures and pressures can be calculated by using the parameters obtained in this work. The PR-BM EOS performed better than the PR EOS, and the average absolute deviations over the temperature range of 255.98 408.15 K calculated by the PR EOS and PR-BM EOS were less than 5.74% and 3.36%, respectively. The results calculated by the two EOS were compared with those calculated by other models, such as PPR78, PR + LCVM + UNIFAC, KIE + PR EOS + HV, and PSRK. The phase equilibrium data of CO 2 butane decane, CO 2 hexane decane, and C O 2 octane decane ternary mixtures were calculated by the two EOS. The average overall deviations for the CO 2 mole fractions calculated by the two EOS were less than 7.66%.
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.
文摘a gliding arc driven by the transverse magnetic field was ignited between the electrodes with a complicated shape at atmospheric pressure and a non-equilibrium plasma was gencrated. Under our experimental conditions, a phenomenon was clearly observed where the arc power decreased with the increase in arc voltage. As the arc voltage was higher than 3.375 kV, the are power acquired from the power supply decreased, and the arc plasma began to switch to a non-equilibrium phase. The existence of the non-equilibrium arc plasma was very short, about 10 ms in one gliding arc discharge cycle.
文摘Vapor-liquid phase equilibrium data including composition,densities,molar volume and equilibrium constant of isobutanol in supercritical carbon dioxide from 313.2K to 353.2K were measured in a variable-volume visual cell.The properties of critical point were obtained by extrapolation.The results showed that critical temperature,critical pressure and critical compressibility factor of CO2-isobutanol system decreased with the increase of critical CO2 content.The phase equilibrium model was established by Peng-Robinson equation of state and van der Waals-2 mixing regulation,and model parameters were determined by optimization calculation of nonlinear least square method.The correlation between calculated values and the experimental data showed good agreement.
基金Financial supports from the National Natural Science Foundation of China (21276194 and 21306136)Key Laboratory of Salt Lake Resources and Chemistry at Chinese Academy Sciences (KLSLRC-KF-13-HX-2)Tianjin Key Laboratory of Marine Resources and Chemistry (201206)
文摘1 Introduction The brines with high concentrations of magnesium and boron resources are widely distributed in the Qaidam Basin of the Qinghai-Tibet plateau,China(Zheng&Tang,1988).Although some works on the ternary system
基金This project is supported by National Natural Science Foundation of China
文摘Swelling capacity of vinyl chloride (VC) in chlorinated polyethylene (CPE) with 25—40 wt% Cl at temperature 30—57℃ was studied and their relationships were correlated with Langmuir and Freundlich adsorption equations. A ternary phase diagram for VC-CPE-PVC was also established. In-situ polymerization conditions of CPE-g-VC were proposed and CPE content control was analyzed for the manufacturing process of CPE-g-VC graft product based on results of phase equilibrium study.
文摘This research study aims to enhance the optimization performance of a newly emerged Aquila Optimization algorithm by incorporating chaotic sequences rather than using uniformly generated Gaussian random numbers.This work employs 25 different chaotic maps under the framework of Aquila Optimizer.It considers the ten best chaotic variants for performance evaluation on multidimensional test functions composed of unimodal and multimodal problems,which have yet to be studied in past literature works.It was found that Ikeda chaotic map enhanced Aquila Optimization algorithm yields the best predictions and becomes the leading method in most of the cases.To test the effectivity of this chaotic variant on real-world optimization problems,it is employed on two constrained engineering design problems,and its effectiveness has been verified.Finally,phase equilibrium and semi-empirical parameter estimation problems have been solved by the proposed method,and respective solutions have been compared with those obtained from state-of-art optimizers.It is observed that CH01 can successfully cope with the restrictive nonlinearities and nonconvexities of parameter estimation and phase equilibrium problems,showing the capabilities of yielding minimum prediction error values of no more than 0.05 compared to the remaining algorithms utilized in the performance benchmarking process.
基金financially supported by the National Key Research and Development Program of China (No.2022YFE03170002)the National Natural Science Foundation of China (Nos.52071286 and U2030208)。
文摘Efficient capture,safe storage and release of tritium from the international thermonuclear experimental reactor(ITER) reaction exhaust gas is a perplexing problem,and the development of an efficient tritium-getter material with ultra-low hydrogenation equilibrium pressure is considered as a reliable way.In this work,Zr_(2)Co alloy was selected as a tritium-getter material and prepared through induction levitation melting.Fundamental performance test results show that Zr_(2)Co exhibits an ultra-low hydrogenation equilibrium pressure of 3.22 × 10^(-6) Pa at 25℃ and excellent hydriding kinetics under a low hydrogen pressure of 0.005 MPa.Interestingly,unique phase transition behaviors were presented in Zr_(2)Co-H system.Specifically,Zr_(2)CoH_(5) formed by Zr_(2)Co hydrogenated at room temperature is initially decomposed into ZrH_(2) and ZrCoH_(3) at200 ℃.With the temperature increasing to 350 ℃,ZrCoH_(3)is dehydrogenated to ZrCo,and then ZrCo further reacts with ZrH_(2) at 650 ℃ to reform Zr_(2)Co and hydrogen.Among the staged phase transition pathways during dehydrogenation,the decomposition of Zr_(2)CoH_(5) occurs preferentially,which is well accordance with both the smallest reaction energy barrier and the maximum reaction spontaneity that are determined respectively from kinetics activation energy and thermodynamics Gibbs free energy.Furthermore,first principles calculation results indicate that the stronger binding of hydrogen in interstitial environments of ZrCoH_(3)and ZrH_(2) triggers the hydrogen-stabilized phase transformation of Zr_(2)CoH_(5).The unique phase transition mechanisms in Zr_(2)Co-H system can shed light on the further exploration and regulation of analogous staged phase transition of hydrogen storage materials.
文摘The phase equilibrium information of slag plays an important role in pyrometallurgical processes to obtain optimum fluxing conditions and operating temperatures.The smelting reduction of titanomagnetite and ilmenite ores in an iron blast furnace(BF)can form Ti(C,N)particles,causing the increased viscosities of slag and hot metal.HIsmelt has been developed in recent years for ironmaking and does not need coke and sinter.The formation of Ti(C,N)in the HIsmelt process is avoided because the oxygen partial pressure in the process is higher than that in the BF.The smelting of TiO_(2)-containing ores in the HIsmelt process results in Al_(2)O_(3)-MgO-SiO_(2)-CaO-TiO_(2)slag.Phase equilibrium in this slag system has been investigated using equilibration,quenching,and electron probe microanalysis techniques.The experimental results were presented in two pseudo-binary sections,which represent the process of HIsmelt for the treatment of 100%titanomagnetite ore and mixed titanomagnetite+ilmenite ore(mass ratio of 2:1),respectively.The primary phases observed in the composition range investigated include pseudo-brookite M_(3)O_(5)(MgO·2TiO_(2)-Al_(2)O_(3)·TiO_(2)),spinel(MgO·Al_(2)O_(3)),perovskite CaTiO_(3),and rutile TiO_(2).The results show that the liquidus temperatures decrease in the TiO_(2)and M_(3)O_(5) primary phase fields and increase in the spinel and CaTiO_(3)primary phase fields with the increase in CaO concentration.The calculation of solid-phase fractions from the experimental data has been demonstrated.The effect of basicity on the liquidus temperatures of the slag has been discussed.The smelting of titanomagnetite plus ilmenite ores has significant advantages to obtain low-sulfur hot metal and high-TiO_(2)slag.Experimentally determined liquidus temperatures were compared with the FactSage predictions to evaluate the existing thermodynamic databases.
文摘A new non-cubic equation of state is proposed for calculation of the thermodynamic properties ofnonpolar and polar fluids and their mixtures,including,saturated vapor pressure,saturated liquid volume,saturated vapor volume,heats of vaporization and vapor-liquid equilibria.The new equation is derived from thegeneralized van der Waals partition function in which the repulsive terms are expressed with the Carnahan andStarling equation for hard spheres,and the attractive terms are made up of the dispersive energy and theChemical association energy. The rules of dependence of parameters α and σ and on temperature are considered broadly so that the newequation yields good agreement with experimental saturated properties of 20 nonpolar and 27 polar fluids in therange of reduced temperatures of 0.5 to 1.0 The new equation with parameters group-contributed generally givessatisfactory predictions on saturated properties. Correlations of vapor-liquid equilibrium data for alcohol-containing systems by using van
文摘Here we review a new class of mixing rules (hat have extended range of mixtures and conditions that can now be described by equation of state models. One characteristic of these mixing rules is that they simultaneously satisfy the boundary conditions of producing a second virial coefficient that is quadratic in mole fraction, and a free energy of mixing like that of an activity coefficient model at high density, though the mixing rule is itself independent of density. We show that using this mixing rule, various asymmetric, highly nonideal mixtures can be accurately described. One serendipitous result is that the parameters in this mixing rule model are almost independent of temperature, which allows accurate extrapolations of phase behavior to be made over large ranges of temperature and pressure.
文摘A flow apparatus was set up for measuring the solubility of a solid solute in a supercritical fluid withthe presence of a small amount of entrainer.The solubilities of biphenyl,diphenylamine and benzoic acid insupercritical carbon dioxide with one of the selected entrainers which were ethanol,acetone and n-hexanerespectively,were obtained in the pressure range of 10—32 MPa and the temperature range of 308—318K.Asolvolytic association theory has been proposed to explain the mechanism of entrainer effect,and theexperimental results were reasonably analysed.According to the solvolytic association theory,the association equa-tion of state was adopted to correlate the experimental data with good accuracy.
基金the National Natural Science Foundation of China (50471025)Natural Science Foundation of Lia-oning Province (20052028)National Key Technology R &D Program(2006BAE04B09-7)
文摘Alloys of Mg-Zn-La system in Mg rich corner were prepared, and the phase relationship was investigated at different temperatures such as 200, 300 and 350 ℃ by scanning electron microscopy(SEM), X-ray diffraction(XRD) and electron probe microanalysis with energy dispersive X-ray spectroscopy (EPMA). Two types of phase equilibrium were identified at the different temperatures. One is two-phase equilibrium contained the Mg solid solution and T-phase. The other is three-phase equilibrium which contained the Mg solid solution, MgZn phase and T-phase. T-phase was stable as the temperature changed. The La content in T-phase is constant which is about 8±0.3% (atom fraction); but the Mg content and Zn content of that is changed, and the Zn content in T-phase was from 16.1% to 44%. The solubility of La in MgZn phase was increased from 1.2% to 1.6% as the temperature increasing from 200 to 350 ℃.
