In this paper,the solid waste desulfurization gypsum produced by coal-fired power plants was used as a raw material to prepare calcium sulfate whiskers with high application prospects.Calcium sulfate whiskers with uni...In this paper,the solid waste desulfurization gypsum produced by coal-fired power plants was used as a raw material to prepare calcium sulfate whiskers with high application prospects.Calcium sulfate whiskers with uniform morphology and high aspect ratio can be prepared by hydrothermal method in sulfuric acid solution.A new process of desulfurization gypsum activated by high-energy grinding to reduce the reaction temperature and sulfuric acid concentration was developed.Through the comparison of product morphology,the best grinding time was determined to be 3.5 h.The mechanism of desulfurization gypsum through physical–chemical coupling to reduce energy consumption was clarified.The activation of desulfurization gypsum by grinding and the acidic environment provided by the sulfuric acid solution made the calcium sulfate solution reached rapid saturation and accelerated the nucleation rate.By calculating the conversion and crystallization rate of calcium sulfate whiskers,it was found that there were obvious"autocatalytic"kinetic characteristics during the crystallization process.展开更多
The Self-Propping Phase-transition Fracturing Technology(SPFT)represents a novel and environmentally friendly approach for a cost-effective and efficient development of the world’s abundant unconventional resources,e...The Self-Propping Phase-transition Fracturing Technology(SPFT)represents a novel and environmentally friendly approach for a cost-effective and efficient development of the world’s abundant unconventional resources,especially in the context of a carbon-constrained sustainable future.SPFT involves the coupling of Thermal,Hydraulic,Mechanical,and Chemical(THMC)fields,which makes it challenging to understand the mechanism and path of hydraulic fracture propagation.This study addresses these challenges by developing a set of THMC multifield coupling models based on SPFT parameters and the physical/chemical characteristics of the Phase-transition Fracturing Fluid System(PFFS).An algorithm,integrating the Finite Element Method,Discretized Virtual Internal Bonds,and Element Partition Method(FEM-DVIB-EPM),is proposed and validated through a case study.The results demonstrate that the FEM-DVIB-EPM coupling algorithm reduces complexity and enhances solving efficiency.The length of the hydraulic fracture increases with the quantity and displacement of PFFS,and excessive displacement may result in uncontrolled fracture height.Within the parameters considered,a minimal difference in fracture length is observed when the PFFS amount exceeds 130 m^(3),that means the fracture length tends to stabilize.This study contributes to understanding the hydraulic fracture propagation mechanism induced by SPFT,offering insights for optimizing hydraulic fracturing technology and treatment parameters.展开更多
Chemical synaptic couplings are more common than electric(gap junction) connections in neurons.In this paper,the firing synchronizations induced by chemical synaptic coupling in chemically delayed scale-free networks ...Chemical synaptic couplings are more common than electric(gap junction) connections in neurons.In this paper,the firing synchronizations induced by chemical synaptic coupling in chemically delayed scale-free networks of modified Hodgkin-Huxley neurons have been studied.It was found that the chemical coupling-induced synchronization transitions are delay-dependent and much different for various delay lengths.In the absence of delay,the neurons exhibit a transition from chaotic bursting(CB) to bursting synchronization(BS) with desynchronized spikes in each burst;for smaller delay lengths,the firing evolves from CB to spiking synchronization(SS),but for larger delay lengths,there are transitions from CB to intermittently multiple SS behaviors.These findings show that the chemical coupling-induced firing synchronization transitions strongly depend on the chemical delay lengths,and intermittently multiple SS can only occur for larger delay lengths.This result would be helpful for better understanding the joint roles of the chemical coupling and chemical delay in the firing activity of the neurons.展开更多
This study aimed to investigate the effects of ammonia addition on ethylene counter-flow diffusion flames with different diluents on the fuel or oxidizer side,using kinetic analyses.A special emphasis was put on asses...This study aimed to investigate the effects of ammonia addition on ethylene counter-flow diffusion flames with different diluents on the fuel or oxidizer side,using kinetic analyses.A special emphasis was put on assessing the coupled chemical effects of NH_(3) and CO_(2) on C2H4 combustion chemistry.The chemical effects could be evaluated by comparing fictitious inert NH_(3) or CO_(2) with normal active NH_(3) or CO_(2).The results revealed that the addition of NH_(3) decreased the mole fractions and production rates of key soot precursors,such as acetylene,propynyl,and benzene.When CO_(2) was used as the dilution gas,the coupled chemical effects of NH_(3) and CO_(2) were affected by the chemical effects of CO_(2) to varying degrees.With the oxidizer-side CO_(2) addition,the coupled chemical effects of NH_(3) and CO_(2) reduced the mole fractions of H,O,OH radicals,acetylene,propynyl,and benzene,while the effects differed from the fuel-side CO_(2) addition.The coupled chemical effects of NH_(3) and CO_(2) also promoted the formation of aldehyde contaminants,such as acetaldehyde,to some extent,particularly with CO_(2) addition on the oxidizer side.展开更多
The inductively coupled plasma chemical vapor deposition(ICP-CVD) deposited silicon nitride(SiN_(x)) thin film was evaluated for its application as the electrical insulating film for a capacitor device.In order to ach...The inductively coupled plasma chemical vapor deposition(ICP-CVD) deposited silicon nitride(SiN_(x)) thin film was evaluated for its application as the electrical insulating film for a capacitor device.In order to achieve highest possible dielectric strength of SiN_(x),the process parameters of ICP-CVD were carefully tuned to control hydrogen in SiN_(x) films by means of tuning N_(2)/SiH_(4) ratio and radio frequency(RF) power.Besides electrical measurements,the hydrogen content in the films was measured by dynamic secondary ion mass spectrometry(D-SIMS).Fourier transform infrared spectroscopy(FTIR) and micro Raman spectroscopy were used to characterize the SiN_(x) films by measuring Si-H and N-H bonds’ intensities.It was found that the more Si-H bonds lead to the higher dielectric strength.展开更多
A stochastic model of chemical reaction-heat conduction-diffusion for a one-dimensional gaseous system under Dirichlet or zero-fluxes boundary conditions is proposed in this paper. Based on this model,we extend the th...A stochastic model of chemical reaction-heat conduction-diffusion for a one-dimensional gaseous system under Dirichlet or zero-fluxes boundary conditions is proposed in this paper. Based on this model,we extend the theory of the broadening exponent of critical fluctuations to cover the chemical reaction-heat conduction coupling systems as an asymptotic property of the corresponding Markovian master equation (ME),and establish a valid stochastic thermodynamics for such systems. As an illustration,the non-isothermal and inhomogeneous Schl-gl model is explicitly studied. Through an order analysis of the contributions from both the drift and diffusion to the evolution of the probability distribution in the corresponding Fokker-Planck equation(FPE) in the approach to bifurcation,we have identified the critical transition rule for the broadening exponent of the fluctuations due to the coupling between chemical reaction and heat conduction. It turns out that the dissipation induced by the critical fluctuations reaches a deterministic level,leading to a thermodynamic effect on the nonequilibrium physico-chemical processes.展开更多
The condition of occurrence of the thermodynamic coupling of chemical reactions is analysed from kinetics. It is found that the thermodynamic coupling is impossible for those reactions which obey kinetically the mass ...The condition of occurrence of the thermodynamic coupling of chemical reactions is analysed from kinetics. It is found that the thermodynamic coupling is impossible for those reactions which obey kinetically the mass action law. The thermodynamic coupling of chemical reactions is further analysed in the case with catalyst. It is found that the thermodynamic coupling which is impossible without catalyst may become possible by introducing proper catalyst into the system. This implies that the catalysts can change not only the rates of chemical reactions, but also the behaviors of thermodynamic coupling of chemical reactions, including the direction of some reactions. Such role of catalysts comes into play not by changing the total free energy of the system, but by changing the reaction mechanism.展开更多
Comprehensive two-dimensional liquid chromatography platform(LC×LC)coupled with quadrupole time-of-flight(QTOF)mass spectrometry(MS)is developed to separate,identify and relatively determine the chemical constitu...Comprehensive two-dimensional liquid chromatography platform(LC×LC)coupled with quadrupole time-of-flight(QTOF)mass spectrometry(MS)is developed to separate,identify and relatively determine the chemical constituents of two types of tripterygium glycosides tablets(TGT).The types and relative contents of the constituents discovered in two kinds of TGT tablets were subsequently compared.C8andC18 column were used for the separation of the first展开更多
The deterioration of the microscopic pore structure of concrete under external sulfate attack(ESA)is a primary cause of degradation.Nevertheless,little effort has been invested in exploring the temporal and spatial de...The deterioration of the microscopic pore structure of concrete under external sulfate attack(ESA)is a primary cause of degradation.Nevertheless,little effort has been invested in exploring the temporal and spatial development of the porosity of concrete under ESA.This study proposes a mechanical–chemical model to simulate the spatiotemporal distribution of the porosity.A relationship between the corrosion damage and amount of ettringite is proposed based on the theory of volume expansion.In addition,the expansion strain at the macro-scale is obtained using a stress analysis model of composite concentric sphere elements and the micromechanical mean-field approach.Finally,considering the influence of corrosion damage and cement hydration on the diffusion of sulfate ions,the expansion deformation and porosity space−time distribution are obtained using the finite difference method.The results demonstrate that the expansion strains calculated using the suggested model agree well with previously reported experimental results.Moreover,the tricalcium aluminate concentration,initial elastic modulus of cement paste,corrosion damage,and continuous hydration of cement significantly affect concrete under ESA.The proposed model can forecast and assess the porosity of concrete covers and provide a credible approach for determining the residual life of concrete structures under ESA.展开更多
基金supported by the State Key Laboratory of Mineral Processing Science and Technology Open Fund(BGRIMM-KJSKL-2017-16)Liaoning Provincial Department of Education Youth Project(LJ2017QL028)Coal Resource Safety Mining and Clean Utilization Engineering Research Center Open Fund(LNTU15KF18)。
文摘In this paper,the solid waste desulfurization gypsum produced by coal-fired power plants was used as a raw material to prepare calcium sulfate whiskers with high application prospects.Calcium sulfate whiskers with uniform morphology and high aspect ratio can be prepared by hydrothermal method in sulfuric acid solution.A new process of desulfurization gypsum activated by high-energy grinding to reduce the reaction temperature and sulfuric acid concentration was developed.Through the comparison of product morphology,the best grinding time was determined to be 3.5 h.The mechanism of desulfurization gypsum through physical–chemical coupling to reduce energy consumption was clarified.The activation of desulfurization gypsum by grinding and the acidic environment provided by the sulfuric acid solution made the calcium sulfate solution reached rapid saturation and accelerated the nucleation rate.By calculating the conversion and crystallization rate of calcium sulfate whiskers,it was found that there were obvious"autocatalytic"kinetic characteristics during the crystallization process.
基金supported by the National Natural Science Foundation of China(52179112)the Open Fund of National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University)(PLN2023-02)Fundamental Research Funds for the Central Universities(2021FZZX001-14).
文摘The Self-Propping Phase-transition Fracturing Technology(SPFT)represents a novel and environmentally friendly approach for a cost-effective and efficient development of the world’s abundant unconventional resources,especially in the context of a carbon-constrained sustainable future.SPFT involves the coupling of Thermal,Hydraulic,Mechanical,and Chemical(THMC)fields,which makes it challenging to understand the mechanism and path of hydraulic fracture propagation.This study addresses these challenges by developing a set of THMC multifield coupling models based on SPFT parameters and the physical/chemical characteristics of the Phase-transition Fracturing Fluid System(PFFS).An algorithm,integrating the Finite Element Method,Discretized Virtual Internal Bonds,and Element Partition Method(FEM-DVIB-EPM),is proposed and validated through a case study.The results demonstrate that the FEM-DVIB-EPM coupling algorithm reduces complexity and enhances solving efficiency.The length of the hydraulic fracture increases with the quantity and displacement of PFFS,and excessive displacement may result in uncontrolled fracture height.Within the parameters considered,a minimal difference in fracture length is observed when the PFFS amount exceeds 130 m^(3),that means the fracture length tends to stabilize.This study contributes to understanding the hydraulic fracture propagation mechanism induced by SPFT,offering insights for optimizing hydraulic fracturing technology and treatment parameters.
基金supported by the Natural Science Foundation of Shandong Province of China (ZR2009AM016)
文摘Chemical synaptic couplings are more common than electric(gap junction) connections in neurons.In this paper,the firing synchronizations induced by chemical synaptic coupling in chemically delayed scale-free networks of modified Hodgkin-Huxley neurons have been studied.It was found that the chemical coupling-induced synchronization transitions are delay-dependent and much different for various delay lengths.In the absence of delay,the neurons exhibit a transition from chaotic bursting(CB) to bursting synchronization(BS) with desynchronized spikes in each burst;for smaller delay lengths,the firing evolves from CB to spiking synchronization(SS),but for larger delay lengths,there are transitions from CB to intermittently multiple SS behaviors.These findings show that the chemical coupling-induced firing synchronization transitions strongly depend on the chemical delay lengths,and intermittently multiple SS can only occur for larger delay lengths.This result would be helpful for better understanding the joint roles of the chemical coupling and chemical delay in the firing activity of the neurons.
基金National Natural Science Foundation of China(52076110,52106160)Jiangsu Provincial Natural Science Foundation of China(BK20200490,BK20220955)Fundamental Research Funds for the Central Universities(30923010208 and 30920031103).
文摘This study aimed to investigate the effects of ammonia addition on ethylene counter-flow diffusion flames with different diluents on the fuel or oxidizer side,using kinetic analyses.A special emphasis was put on assessing the coupled chemical effects of NH_(3) and CO_(2) on C2H4 combustion chemistry.The chemical effects could be evaluated by comparing fictitious inert NH_(3) or CO_(2) with normal active NH_(3) or CO_(2).The results revealed that the addition of NH_(3) decreased the mole fractions and production rates of key soot precursors,such as acetylene,propynyl,and benzene.When CO_(2) was used as the dilution gas,the coupled chemical effects of NH_(3) and CO_(2) were affected by the chemical effects of CO_(2) to varying degrees.With the oxidizer-side CO_(2) addition,the coupled chemical effects of NH_(3) and CO_(2) reduced the mole fractions of H,O,OH radicals,acetylene,propynyl,and benzene,while the effects differed from the fuel-side CO_(2) addition.The coupled chemical effects of NH_(3) and CO_(2) also promoted the formation of aldehyde contaminants,such as acetaldehyde,to some extent,particularly with CO_(2) addition on the oxidizer side.
基金Project supported by the Natural Science Foundation of Jiangsu Higher Education Institutions of China(Grant Nos.19KJD140002 and 19KJB140008)the Key Projects of Ministry of Science and Technology of China(Grant No.SQ2020YFF0407077)+3 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant Nos.2020XKT786 and KYCX202337)the National Foreign Experts Bureau High-end Foreign Experts Project,China(Grant No.G20190114003)the Key Research and Development Program of Jiangsu Province,China(Grant No.BE2018063)the Scientific Research Program for Doctoral Teachers of JSNU(Grant No.9212218113)。
文摘The inductively coupled plasma chemical vapor deposition(ICP-CVD) deposited silicon nitride(SiN_(x)) thin film was evaluated for its application as the electrical insulating film for a capacitor device.In order to achieve highest possible dielectric strength of SiN_(x),the process parameters of ICP-CVD were carefully tuned to control hydrogen in SiN_(x) films by means of tuning N_(2)/SiH_(4) ratio and radio frequency(RF) power.Besides electrical measurements,the hydrogen content in the films was measured by dynamic secondary ion mass spectrometry(D-SIMS).Fourier transform infrared spectroscopy(FTIR) and micro Raman spectroscopy were used to characterize the SiN_(x) films by measuring Si-H and N-H bonds’ intensities.It was found that the more Si-H bonds lead to the higher dielectric strength.
基金supported by the National Natural Science Foundation of China (20673074 & 20973119)
文摘A stochastic model of chemical reaction-heat conduction-diffusion for a one-dimensional gaseous system under Dirichlet or zero-fluxes boundary conditions is proposed in this paper. Based on this model,we extend the theory of the broadening exponent of critical fluctuations to cover the chemical reaction-heat conduction coupling systems as an asymptotic property of the corresponding Markovian master equation (ME),and establish a valid stochastic thermodynamics for such systems. As an illustration,the non-isothermal and inhomogeneous Schl-gl model is explicitly studied. Through an order analysis of the contributions from both the drift and diffusion to the evolution of the probability distribution in the corresponding Fokker-Planck equation(FPE) in the approach to bifurcation,we have identified the critical transition rule for the broadening exponent of the fluctuations due to the coupling between chemical reaction and heat conduction. It turns out that the dissipation induced by the critical fluctuations reaches a deterministic level,leading to a thermodynamic effect on the nonequilibrium physico-chemical processes.
文摘The condition of occurrence of the thermodynamic coupling of chemical reactions is analysed from kinetics. It is found that the thermodynamic coupling is impossible for those reactions which obey kinetically the mass action law. The thermodynamic coupling of chemical reactions is further analysed in the case with catalyst. It is found that the thermodynamic coupling which is impossible without catalyst may become possible by introducing proper catalyst into the system. This implies that the catalysts can change not only the rates of chemical reactions, but also the behaviors of thermodynamic coupling of chemical reactions, including the direction of some reactions. Such role of catalysts comes into play not by changing the total free energy of the system, but by changing the reaction mechanism.
文摘Comprehensive two-dimensional liquid chromatography platform(LC×LC)coupled with quadrupole time-of-flight(QTOF)mass spectrometry(MS)is developed to separate,identify and relatively determine the chemical constituents of two types of tripterygium glycosides tablets(TGT).The types and relative contents of the constituents discovered in two kinds of TGT tablets were subsequently compared.C8andC18 column were used for the separation of the first
基金support from the National Natural Science Foundation of China(Grant Nos.11832013,52168030)the Education Department of Jiangxi Province Science and Technology Project(No.211909)K.C.Wong Magna Fund in Ningbo University,and the project of the Key Laboratory of Impact and Safety Engineering(Ningbo University),Ministry of Education(No.202004).
文摘The deterioration of the microscopic pore structure of concrete under external sulfate attack(ESA)is a primary cause of degradation.Nevertheless,little effort has been invested in exploring the temporal and spatial development of the porosity of concrete under ESA.This study proposes a mechanical–chemical model to simulate the spatiotemporal distribution of the porosity.A relationship between the corrosion damage and amount of ettringite is proposed based on the theory of volume expansion.In addition,the expansion strain at the macro-scale is obtained using a stress analysis model of composite concentric sphere elements and the micromechanical mean-field approach.Finally,considering the influence of corrosion damage and cement hydration on the diffusion of sulfate ions,the expansion deformation and porosity space−time distribution are obtained using the finite difference method.The results demonstrate that the expansion strains calculated using the suggested model agree well with previously reported experimental results.Moreover,the tricalcium aluminate concentration,initial elastic modulus of cement paste,corrosion damage,and continuous hydration of cement significantly affect concrete under ESA.The proposed model can forecast and assess the porosity of concrete covers and provide a credible approach for determining the residual life of concrete structures under ESA.
