Grate process is an important step in grate-kiln pellet production.However,as a relatively closed system,the process on grate is inaccessible to direct detection,therefore,it is hard to control.As a result,mathematica...Grate process is an important step in grate-kiln pellet production.However,as a relatively closed system,the process on grate is inaccessible to direct detection,therefore,it is hard to control.As a result,mathematical models of temperature distribution,moisture distribution and oxidation degree distribution in pellet bed,with good universality,computation speed and calculation accuracy,are presented based on analysis of heat transfer and physical-chemical reactions during grate process.And real-time visualization of temperature,moisture and oxidation degree distribution in pellet bed during grate process is realized.Model validation is displayed,and the similarity of 91% is proved.The results can reveal real time status on grate,and provide a solid foundation for the subsequent study of artificial intelligence control system of pellet production.展开更多
Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology develop...Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology development. Here a multi-physics model is established for the relevant experimental cells. Balance of electrochemical potentials for the electrochemical reactions, generic rate expression for the methane steam reforming, dusty gas model in a form of Fick＇s model for anode gas transport are used in the model. Excellent agreement between the theoretical and experimental current-voltage relations is obtained, demonstrating the validity of the proposed theoretical model. The steam reaction order in low steam methane reforming reaction is found to be 1. Detailed information about the distributions of physical quantities is obtained by the numerical simulation. Carbon deposition is analyzed in detail and the mechanism for the coking inhibition by operating current is illustrated clearly. Two expressions of carbon activity are analyzed and found to be correct qualitatively, but not quantitatively. The role of anode diffusion layer on reducing the current threshold for carbon removal is also explained. It is noted that the current threshold reduction may be explained quantitatively with the carbon activity models that are only qualitatively correct.展开更多
Fully A-doublet resolved differential cross sections and collision-induced rotational alignment moments have been measured for the NO(X)-Xe collision system at a collision energy of 519 cm^-1.The experiments combine i...Fully A-doublet resolved differential cross sections and collision-induced rotational alignment moments have been measured for the NO(X)-Xe collision system at a collision energy of 519 cm^-1.The experiments combine initial quantum state selection,employing a hexapole inhomogeneous electric field,with quantum state resolved detection,using(1+1')resonantly enhanced multiphoton ionization and velocity map ion imaging.The differential cross sections and polarization dependent differential cross sections are shown to agree well with quantum mechanical scattering calculations performed on ab initio potential energy surfaces[J.Klos et al.J.Chem.Phys.137,014312(2012)].By comparison with quasi-classical trajectory calculations,quantum mechanical scattering calculations on a hard-shell potential,and kinematic apse model calculations,the effects of the attractive part of the potential on the measured differential cross sections and collision-induced rotational alignment moments are assessed.展开更多
The concept of SBCR was put forward to treat sauce wastewater. Further study showed that adding appropriate amount of calcium chloride to SBR can improve the quality of effluent. The removal rate of COD and color was ...The concept of SBCR was put forward to treat sauce wastewater. Further study showed that adding appropriate amount of calcium chloride to SBR can improve the quality of effluent. The removal rate of COD and color was 84% and 80%, 36%, 96% higher than those of traditional SBR respectively. The results of continuous experiments and biophase observing showed that calcium chloride accumulation increased the sludge production slightly while the sludge dewatering characteristic was improved.展开更多
The combustion process of pulverized coal injected into blast furnace involves a lot of physical and chemical reactions. Based on the combustion behaviors of pulverized coal, the conception of coal effective calorific...The combustion process of pulverized coal injected into blast furnace involves a lot of physical and chemical reactions. Based on the combustion behaviors of pulverized coal, the conception of coal effective calorific value representing the actual thermal energy provided for blast furnace was proposed. A cost performance evaluation model of coal injection was built up for the optimal selection of various kinds of coal based on effective calorific value. The model contains two indicators: coal effective calorific value which has eight sub-indicators and coal injection cost which includes four sub-indicators. In addition, the calculation principle and application of cost performance evaluation model in a Chinese large-scale iron and steel company were comprehensively introduced. The evaluation results finally confirm that this novel model is of great significance to the optimal selection of blast furnace pulverized coal.展开更多
The mixed metal/metal sulphide(Ag@CoS)with reduced graphene oxide(rGO)nanocomposite(Ag@CoS/rGO)was synthesized for the possible electrode in supercapacitors.Ag@CoS was successfully deposited on the rGO nanosheets by h...The mixed metal/metal sulphide(Ag@CoS)with reduced graphene oxide(rGO)nanocomposite(Ag@CoS/rGO)was synthesized for the possible electrode in supercapacitors.Ag@CoS was successfully deposited on the rGO nanosheets by hydrothermal method,implying the growth of 2D Ag and CoS-based hexagonal-like structure on the rGO framework.The synthesized nanocomposite was subjected to structural,morphological and electrochemical studies.The XRD results show that the prepared nanocomposite material exhibits a combination of hexagonal and cubic phase due to the presence of CoS and Ag phases together.The band appearing at nearly 470.33 cm^−1 in FTIR spectra can be ascribed to the absorption of S—S bond in the Ag@CoS/rGO nanocomposite.The clear hexagonal structure was analysed by SEM and TEM with the grain sizes ranging from nanometer to micrometer.The electrode material exhibits excellent cyclic stability with a specific capacitance of 1580 F/g at a current density of 0.5 A/g without any loss of capacitive retention even after 1000 cycles.Based on the electrochemical performance,it can be inferred that the prepared novel nanocomposite material is very suitable for using as an electrode for electrochemical supercapacitor applications.展开更多
Efficiency and selectivity of hydrogenating depolymerization of the coal extract benzene-insoluble part over the heterogeneous Co–Mo/Al2O3 catalyst were assessed using a mathematical model. The analytical equations o...Efficiency and selectivity of hydrogenating depolymerization of the coal extract benzene-insoluble part over the heterogeneous Co–Mo/Al2O3 catalyst were assessed using a mathematical model. The analytical equations of the mathematical model were generated based on material balance incorporating the physico-chemical phenomena(reaction and diffusion) both in the autoclave and the catalyst grain. The equations offer the possibility for predicting changes of the reactants in the autoclave during the process and for determining the distribution of reactant concentrations in the grain as a function of its radius. The analytical equations of the model serve as the basis of the algorithm for assessing the influence of restrictive diffusion on the effectiveness and selectivity of the catalyst, and also for defining the optimal radii of the catalyst's pores to enable free transport of reactants in the grain interior.展开更多
The van der Waals (vdW) interaction is very important in fields of physics, biology and chemistry, and its role in reaction dynamics is an issue of great interest. In this review, we focus on the recent progresses in ...The van der Waals (vdW) interaction is very important in fields of physics, biology and chemistry, and its role in reaction dynamics is an issue of great interest. In this review, we focus on the recent progresses in the theoretical and experimental studies on the vdW interaction in bimolecular reactions. In particular, we review those studies that have advanced our understanding of how the vdW interaction can strongly influence the dynamics in both direct activated and complex-forming reactions, and further extend the discussion to the polyatomic reactions involving more atoms and those occurring at cold and ultracold temperatures. We indicate that an accurate description of the delicate vdW structure and long-range potential remains a challenge nowadays in either ab initio calculations or the fitting of the potential energy surfaces. We also present an explanation on the concept of vdW saddle proposed by us recently which may have general importance.展开更多
Computer simulation is a good guide and reference for development and research on petroleum refining processes. Traditionally, pseudo-components are used in the simulation, in which their physical properties are estim...Computer simulation is a good guide and reference for development and research on petroleum refining processes. Traditionally, pseudo-components are used in the simulation, in which their physical properties are estimated by empirical relations and cannot be associated with actual chemical reactions, as no molecular structure is available for pseudo-components. This limitation can be overcome if real components are used. In this paper, a real component based method is proposed for the simulation of a diesel hydrotreating process by using the software of Unisim Design. This process includes reaction units and distillation units. The chemical reaction network is established by analyzing the feedstock. The feedstock is characterized by real components, which are obtained based on true boiling point curve. Simulation results are consistent with actual data.展开更多
As a sister compound of MnBi_(2)Te_(4),the highquality MnSb_(2)Te_(4) single crystals are grown via solid-state reaction where prolonged annealing and narrow temperature window play critical roles on account of its th...As a sister compound of MnBi_(2)Te_(4),the highquality MnSb_(2)Te_(4) single crystals are grown via solid-state reaction where prolonged annealing and narrow temperature window play critical roles on account of its thermal metastability.Single-crystal X-ray diffraction(SCXRD)analysis on MnSb_(2)Te_(4) illustrates a crystal model that is isostructural to MnBi_(2)Te_(4),consisting of Te-Sb-Te-Mn-Te-Sb-Te septuple layers(SLs)stacking in an ABC sequence.However,MnSb_(2)Te_(4) reveals a more pronounced cation intermixing in comparison with MnBi_(2)Te_(4),comprising 28.9(7)%Sb antisite defects on the Mn(3a)site and 19.3(6)%Mn antisite defects on the Sb(6c)site,which may give rise to novel magnetic properties in emerging layered MnBi_(2)Te_(4)-family materials.Unlike the antiferromagnetic(AFM)nature in MnBi_(2)Te_(4),MnSb_(2)Te_(4) exhibits a glassy magnetic ground state below 24 K and can be easily tuned to a ferromagnetic state under a weak applied magnetic field.Its magnetic hysteresis,anisotropy,and relaxation process are investigated in detail via static and dynamic magnetization measurements.Moreover,anomalous Hall effect as a p-type conductor is demonstrated with transport measurements.This work grants MnSb_(2)Te_(4) a possible access to the future exploration of exotic quantum physics by removing the odd/even layer number restraint in realizing quantum transport phenomena in intrinsic AFM MnBi_(2)Te_(4)-family materials,as a result of the crossover between its magnetism and potential topology arising from the Sb-Te layer.展开更多
基金Project(NCET050630) supported by Program for New Century Excellent Talents in University,China
文摘Grate process is an important step in grate-kiln pellet production.However,as a relatively closed system,the process on grate is inaccessible to direct detection,therefore,it is hard to control.As a result,mathematical models of temperature distribution,moisture distribution and oxidation degree distribution in pellet bed,with good universality,computation speed and calculation accuracy,are presented based on analysis of heat transfer and physical-chemical reactions during grate process.And real-time visualization of temperature,moisture and oxidation degree distribution in pellet bed during grate process is realized.Model validation is displayed,and the similarity of 91% is proved.The results can reveal real time status on grate,and provide a solid foundation for the subsequent study of artificial intelligence control system of pellet production.
基金This work was supported by the National Basic Research Program of China （No.2012CB215405）, the National Natural Science Foundation of China （No.11374272）, and the Specialized Research Fund for the Doctoral Program of Higher Education （No.20123402110064）.
文摘Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology development. Here a multi-physics model is established for the relevant experimental cells. Balance of electrochemical potentials for the electrochemical reactions, generic rate expression for the methane steam reforming, dusty gas model in a form of Fick＇s model for anode gas transport are used in the model. Excellent agreement between the theoretical and experimental current-voltage relations is obtained, demonstrating the validity of the proposed theoretical model. The steam reaction order in low steam methane reforming reaction is found to be 1. Detailed information about the distributions of physical quantities is obtained by the numerical simulation. Carbon deposition is analyzed in detail and the mechanism for the coking inhibition by operating current is illustrated clearly. Two expressions of carbon activity are analyzed and found to be correct qualitatively, but not quantitatively. The role of anode diffusion layer on reducing the current threshold for carbon removal is also explained. It is noted that the current threshold reduction may be explained quantitatively with the carbon activity models that are only qualitatively correct.
基金The support of the UK EPSRC to Mark Brouard via Programme Grant EP/L005913/1the Spanish Ministry of Science and Innovation(Grant PGC2018-096444-B-I00 MINECO/FEDER)to F.Javier Aoiz are gratefully acknowledged+2 种基金funding by Fundación Salamanca City of Culture and Knowledge(Programme for attracting Scientific Talent to Salamanca)support through U.S.National Science Foundation under Grant No.CHE-1565872 to Millard H.Alexander.
文摘Fully A-doublet resolved differential cross sections and collision-induced rotational alignment moments have been measured for the NO(X)-Xe collision system at a collision energy of 519 cm^-1.The experiments combine initial quantum state selection,employing a hexapole inhomogeneous electric field,with quantum state resolved detection,using(1+1')resonantly enhanced multiphoton ionization and velocity map ion imaging.The differential cross sections and polarization dependent differential cross sections are shown to agree well with quantum mechanical scattering calculations performed on ab initio potential energy surfaces[J.Klos et al.J.Chem.Phys.137,014312(2012)].By comparison with quasi-classical trajectory calculations,quantum mechanical scattering calculations on a hard-shell potential,and kinematic apse model calculations,the effects of the attractive part of the potential on the measured differential cross sections and collision-induced rotational alignment moments are assessed.
文摘The concept of SBCR was put forward to treat sauce wastewater. Further study showed that adding appropriate amount of calcium chloride to SBR can improve the quality of effluent. The removal rate of COD and color was 84% and 80%, 36%, 96% higher than those of traditional SBR respectively. The results of continuous experiments and biophase observing showed that calcium chloride accumulation increased the sludge production slightly while the sludge dewatering characteristic was improved.
基金Project(51134008)supported by the National Natural Science Foundation of ChinaProject(2012CB720401)supported by the National Basic Research Program of China
文摘The combustion process of pulverized coal injected into blast furnace involves a lot of physical and chemical reactions. Based on the combustion behaviors of pulverized coal, the conception of coal effective calorific value representing the actual thermal energy provided for blast furnace was proposed. A cost performance evaluation model of coal injection was built up for the optimal selection of various kinds of coal based on effective calorific value. The model contains two indicators: coal effective calorific value which has eight sub-indicators and coal injection cost which includes four sub-indicators. In addition, the calculation principle and application of cost performance evaluation model in a Chinese large-scale iron and steel company were comprehensively introduced. The evaluation results finally confirm that this novel model is of great significance to the optimal selection of blast furnace pulverized coal.
文摘The mixed metal/metal sulphide(Ag@CoS)with reduced graphene oxide(rGO)nanocomposite(Ag@CoS/rGO)was synthesized for the possible electrode in supercapacitors.Ag@CoS was successfully deposited on the rGO nanosheets by hydrothermal method,implying the growth of 2D Ag and CoS-based hexagonal-like structure on the rGO framework.The synthesized nanocomposite was subjected to structural,morphological and electrochemical studies.The XRD results show that the prepared nanocomposite material exhibits a combination of hexagonal and cubic phase due to the presence of CoS and Ag phases together.The band appearing at nearly 470.33 cm^−1 in FTIR spectra can be ascribed to the absorption of S—S bond in the Ag@CoS/rGO nanocomposite.The clear hexagonal structure was analysed by SEM and TEM with the grain sizes ranging from nanometer to micrometer.The electrode material exhibits excellent cyclic stability with a specific capacitance of 1580 F/g at a current density of 0.5 A/g without any loss of capacitive retention even after 1000 cycles.Based on the electrochemical performance,it can be inferred that the prepared novel nanocomposite material is very suitable for using as an electrode for electrochemical supercapacitor applications.
文摘Efficiency and selectivity of hydrogenating depolymerization of the coal extract benzene-insoluble part over the heterogeneous Co–Mo/Al2O3 catalyst were assessed using a mathematical model. The analytical equations of the mathematical model were generated based on material balance incorporating the physico-chemical phenomena(reaction and diffusion) both in the autoclave and the catalyst grain. The equations offer the possibility for predicting changes of the reactants in the autoclave during the process and for determining the distribution of reactant concentrations in the grain as a function of its radius. The analytical equations of the model serve as the basis of the algorithm for assessing the influence of restrictive diffusion on the effectiveness and selectivity of the catalyst, and also for defining the optimal radii of the catalyst's pores to enable free transport of reactants in the grain interior.
基金supported by the National Natural Science Foundation of China (No.21773251 and No.91741106)the Beijing National Laboratory for Molecular Sciences and Chinese Academy of Sciences
文摘The van der Waals (vdW) interaction is very important in fields of physics, biology and chemistry, and its role in reaction dynamics is an issue of great interest. In this review, we focus on the recent progresses in the theoretical and experimental studies on the vdW interaction in bimolecular reactions. In particular, we review those studies that have advanced our understanding of how the vdW interaction can strongly influence the dynamics in both direct activated and complex-forming reactions, and further extend the discussion to the polyatomic reactions involving more atoms and those occurring at cold and ultracold temperatures. We indicate that an accurate description of the delicate vdW structure and long-range potential remains a challenge nowadays in either ab initio calculations or the fitting of the potential energy surfaces. We also present an explanation on the concept of vdW saddle proposed by us recently which may have general importance.
文摘Computer simulation is a good guide and reference for development and research on petroleum refining processes. Traditionally, pseudo-components are used in the simulation, in which their physical properties are estimated by empirical relations and cannot be associated with actual chemical reactions, as no molecular structure is available for pseudo-components. This limitation can be overcome if real components are used. In this paper, a real component based method is proposed for the simulation of a diesel hydrotreating process by using the software of Unisim Design. This process includes reaction units and distillation units. The chemical reaction network is established by analyzing the feedstock. The feedstock is characterized by real components, which are obtained based on true boiling point curve. Simulation results are consistent with actual data.
基金supported by the Basic Science Center Project of the National Natural Science Foundation of China(51788104)the Ministry of Science and Technology of China(2018YFA0307100)+1 种基金the National Natural Science Foundation of China(51991340 and 21975140)supported by the Beckman Young Investigator award。
文摘As a sister compound of MnBi_(2)Te_(4),the highquality MnSb_(2)Te_(4) single crystals are grown via solid-state reaction where prolonged annealing and narrow temperature window play critical roles on account of its thermal metastability.Single-crystal X-ray diffraction(SCXRD)analysis on MnSb_(2)Te_(4) illustrates a crystal model that is isostructural to MnBi_(2)Te_(4),consisting of Te-Sb-Te-Mn-Te-Sb-Te septuple layers(SLs)stacking in an ABC sequence.However,MnSb_(2)Te_(4) reveals a more pronounced cation intermixing in comparison with MnBi_(2)Te_(4),comprising 28.9(7)%Sb antisite defects on the Mn(3a)site and 19.3(6)%Mn antisite defects on the Sb(6c)site,which may give rise to novel magnetic properties in emerging layered MnBi_(2)Te_(4)-family materials.Unlike the antiferromagnetic(AFM)nature in MnBi_(2)Te_(4),MnSb_(2)Te_(4) exhibits a glassy magnetic ground state below 24 K and can be easily tuned to a ferromagnetic state under a weak applied magnetic field.Its magnetic hysteresis,anisotropy,and relaxation process are investigated in detail via static and dynamic magnetization measurements.Moreover,anomalous Hall effect as a p-type conductor is demonstrated with transport measurements.This work grants MnSb_(2)Te_(4) a possible access to the future exploration of exotic quantum physics by removing the odd/even layer number restraint in realizing quantum transport phenomena in intrinsic AFM MnBi_(2)Te_(4)-family materials,as a result of the crossover between its magnetism and potential topology arising from the Sb-Te layer.
