For unacceptable computational efficiency and accuracy on the probabilistic analysis of multi-component system with multi-failure modes,this paper proposed multi-extremum response surface method(MERSM).MERSM model was...For unacceptable computational efficiency and accuracy on the probabilistic analysis of multi-component system with multi-failure modes,this paper proposed multi-extremum response surface method(MERSM).MERSM model was established based on quadratic polynomial function by taking extremum response surface model as the sub-model of multi-response surface method.The dynamic probabilistic analysis of an aeroengine turbine blisk with two components,and their reliability of deformation and stress failures was obtained,based on thermal-structural coupling technique,by considering the nonlinearity of material parameters and the transients of gas flow,gas temperature and rotational speed.The results show that the comprehensive reliability of structure is 0.9904 when the allowable deformations and stresses of blade and disk are 4.78×10–3 m and 1.41×109 Pa,and 1.64×10–3 m and 1.04×109 Pa,respectively.Besides,gas temperature and rotating speed severely influence the comprehensive reliability of system.Through the comparison of methods,it is shown that the MERSM holds higher computational precision and speed in the probabilistic analysis of turbine blisk,and MERSM computational precision satisfies the requirement of engineering design.The efforts of this study address the difficulties on transients and multiple models coupling for the dynamic probabilistic analysis of multi-component system with multi-failure modes.展开更多
Painleve property of the （2＋1）-dimensional multi-component Broer-Kaup （BK） system is considered by using the standard Weiss Kruskal approaches. Applying the Clarkson and Kruskal （CK） direct method to the （2＋1...Painleve property of the （2＋1）-dimensional multi-component Broer-Kaup （BK） system is considered by using the standard Weiss Kruskal approaches. Applying the Clarkson and Kruskal （CK） direct method to the （2＋1）- dimensional multi-component BK system, some types of similarity reductions are obtained. By solving the reductions, one can get the solutions of the （2＋1）-dimensional multi-component BK system.展开更多
Objective: to establish multi-components by single marker (QAMS) and HPlC method for the determination of four substances (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin and to provide experimental basis ...Objective: to establish multi-components by single marker (QAMS) and HPlC method for the determination of four substances (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin and to provide experimental basis for the quality standard of Compound Yizhihao Granules. Methods: the sample treatment method was improved, and HPLC external standard method was established for the determination of four substances in Compound Yizhihao Granules. The chromatographic column was Wondersil C18 (4.6mm×250mm, 5μm), the flow rate was 1.0mL/min, the check wavelength was 245nm, the column temperature was 30℃, the sample was 20 μL, the mobile phase was acetonitrile-water. The relative correction factors (RCF) of (R, S) - Epigoitrin, Vitexicarpin, Artemisetin were determined with Indirubin as internal reference. The RCF was used to calculate the content of the substance under test, and then the content of the substance under test was determined by the external standard method to verify the feasibility of the multi-components by single marker. Results: the treatment method of the test sample was as follows: solid-liquid ratio was 1:5. Ultrasound was 45 min, trichloromethane extraction, and steam dry concentration with methanol constant volume. The results showed that the good linear ranges of (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin were 5.15-103 μ g / mL, 5.005-100.1 μ g / mL, 0.5-10 μ g / mL and 0.5115-10.23 μ g / mL, respectively. The average recoveries were 95.19%, 95.73%, 90.75%, 91.65%. The relative correction factors (RCF) of (R, S) - Epigoitrin, Vitexicarpin, Artemisetin were determined with Indirubin as internal reference was 0.2%, 0.6% and 0.3%. And the relative error of multi-components by single marker and external standard method was less than 1%. Conclusion: the multi-components by single marker method (QAMS) is simple, stable and can be used for the determination of multiple substances in Compound Yizhihao Granules.展开更多
The fatigue life of aeroengine turbine disc presents great dispersion due to the randomness of the basic variables,such as applied load,working temperature,geometrical dimensions and material properties.In order to am...The fatigue life of aeroengine turbine disc presents great dispersion due to the randomness of the basic variables,such as applied load,working temperature,geometrical dimensions and material properties.In order to ameliorate reliability analysis efficiency without loss of reliability,the distributed collaborative response surface method(DCRSM) was proposed,and its basic theories were established in this work.Considering the failure dependency among the failure modes,the distributed response surface was constructed to establish the relationship between the failure mode and the relevant random variables.Then,the failure modes were considered as the random variables of system response to obtain the distributed collaborative response surface model based on structure failure criterion.Finally,the given turbine disc structure was employed to illustrate the feasibility and validity of the presented method.Through the comparison of DCRSM,Monte Carlo method(MCM) and the traditional response surface method(RSM),the results show that the computational precision for DCRSM is more consistent with MCM than RSM,while DCRSM needs far less computing time than MCM and RSM under the same simulation conditions.Thus,DCRSM is demonstrated to be a feasible and valid approach for improving the computational efficiency of reliability analysis for aeroengine turbine disc fatigue life with multiple random variables,and has great potential value for the complicated mechanical structure with multi-component and multi-failure mode.展开更多
Four components have been reacted in water and in the presence of N-morpholine yielded pyrnopyrazole as a simple substrate for novel N2-acyclonucleoside derivatives of fused pyranopyrazole. The sodium salt of fused py...Four components have been reacted in water and in the presence of N-morpholine yielded pyrnopyrazole as a simple substrate for novel N2-acyclonucleoside derivatives of fused pyranopyrazole. The sodium salt of fused pyranopyrazole reacted with halo alcohols led to the formation of new scaffolds from fused pyranopyrazole derivatives. All newly prepared compounds are characterized spectroscopically.展开更多
Understanding the dynamics of phase boundaries in fluids requires quantitative knowledge about the microscale processes at the interface.We consider the sharp-interface motion of the compressible two-component flow an...Understanding the dynamics of phase boundaries in fluids requires quantitative knowledge about the microscale processes at the interface.We consider the sharp-interface motion of the compressible two-component flow and propose a heterogeneous multiscale method(HMM)to describe the flow fields accurately.The multiscale approach combines a hyperbolic system of balance laws on the continuum scale with molecular-dynamics(MD)simulations on the microscale level.Notably,the multiscale approach is necessary to compute the interface dynamics because there is—at present—no closed continuum-scale model.The basic HMM relies on a moving-mesh finite-volume method and has been introduced recently for the compressible one-component flow with phase transitions by Magiera and Rohde in(J Comput Phys 469:111551,2022).To overcome the numerical complexity of the MD microscale model,a deep neural network is employed as an efficient surrogate model.The entire approach is finally applied to simulate droplet dynamics for argon-methane mixtures in several space dimensions.To our knowledge,such compressible two-phase dynamics accounting for microscale phase-change transfer rates have not yet been computed.展开更多
Understanding the effects of point liquid loading on transversely isotropic poroelastic media is crucial for advancing geomechanics and biomechanics, where precise modeling of fluid-structure interactions is essential...Understanding the effects of point liquid loading on transversely isotropic poroelastic media is crucial for advancing geomechanics and biomechanics, where precise modeling of fluid-structure interactions is essential. This paper presents a comprehensive analysis of infinite transversely isotropic poroelasticity under a fluid source, based on Biot's theory, aiming to uncover new and previously unexplored insights in the literature. We begin our study by deriving a general solution for fluid-saturated, transversely isotropic poroelastic materials in terms of harmonic functions that satisfy sixth-order homogeneous partial differential equations, using potential theory and Almansi's theorem. Based on these general solutions and potential functions, we construct a Green's function for a point fluid source, introducing three new harmonic functions with undetermined constants. These constants are determined by enforcing continuity and equilibrium conditions. Substituting these into the general solution yields fundamental solutions for poroelasticity that provide crucial support for a wide range of project problems. Numerical results and comparisons with existing literature are provided to illustrate physical mechanisms through contour plots. Our observations reveal that all components tend to zero in the far field and become singular at the concentrated source. Additionally, the contours exhibit rapid changes near the point fluid source but display gradual variations at a distance from it. These findings highlight the intricate behavior of the system under point liquid loading, offering valuable insights for further research and practical applications.展开更多
Herein,we developed a tertiary amine-catalyzed stereoretentive multi-component cascade reaction featuring an amidation/[4+1]annulation/decarboxylation/Curtius rearrangement/[2+n]annulation sequence.This metal-free and...Herein,we developed a tertiary amine-catalyzed stereoretentive multi-component cascade reaction featuring an amidation/[4+1]annulation/decarboxylation/Curtius rearrangement/[2+n]annulation sequence.This metal-free and step-economic method provided a broad range of cyclic ureas/urethanes in green solvent under mild conditions without employing explosive and toxic reagents.Importantly,this reaction generated isocyanates in situ under catalytic conditions via a decarboxylation/Curtius rearrangement process of dioxazolones.展开更多
To predict the soil-water characteristic curve(i.e.SWCC)of natural and remoulded Malan loess from soil physical properties,one-point methods for determining the SWCC that are much simpler than experimental methods are...To predict the soil-water characteristic curve(i.e.SWCC)of natural and remoulded Malan loess from soil physical properties,one-point methods for determining the SWCC that are much simpler than experimental methods are proposed.The predicted SWCC is presented in the form of the BRUTSAERT equation,in which the four model parameters can be estimated from soil physical properties using the best correlations obtained in the present study along with one measured data point.The proposed one-point methods are validated using the measured SWCC data reported in the literature.The results of validation studies suggest that the proposed one-point methods can provide reasonable prediction of the SWCC for natural and remoulded Malan loess.The measured data point should be within the transition zone;the measured suction is suggested between25to100kPa for natural loess,while between100to500kPa for remoulded loess.展开更多
By using the phase field model for the solidification of multi-component alloys and coupling with real thermodynamic data, the dendritic morphology transition and the dendritic micro-segregation of Ni-Al-Nb ternary al...By using the phase field model for the solidification of multi-component alloys and coupling with real thermodynamic data, the dendritic morphology transition and the dendritic micro-segregation of Ni-Al-Nb ternary alloys are simulated in two cases, i.e., varying the alloy composition at a fixed under-cooling and varying the undercooling at a fixed alloy composition. The simulated results indicate that with the increase of the dimensionless undercooling U (U=ΔT/ΔT0, where ΔT is the undercooling and ΔT0 the temperature interval between the solidus and liquidus), the dendritic morphology transfers from dendritic to globular growth in both cases. As to the dendritic micro-segregation, both cases present a regularity of increasing at first and then decreasing.展开更多
In the past 15 years,the shale gas revolution and large-scale commercial developments in the United States have driven the exploration and development of shale plays worldwide.Among many factors affecting shale gas ex...In the past 15 years,the shale gas revolution and large-scale commercial developments in the United States have driven the exploration and development of shale plays worldwide.Among many factors affecting shale gas exploration potential,the gas-bearing properties of shale(quantity,storage state,composition)and their controlling factors are the essential research attracting wide attention in the academic community.This paper reviews the research progress on the retention mechanism,influencing factors,and evaluation methods for resource potential of the shale gas system,and proposes further research directions.Sorption is the main mechanism of gas retention in organic-rich shales;the gas is mainly stored in nanopores of shale in free and sorption states.The presence of water and nonhydrocarbon gases in pores can complicate the process and mechanism of methane(CH4)sorption,and the related theoretical models still need further development.The in-situ gas content and gasbearing properties of shale are governed by the geological properties(organic matter abundance,kerogen type,thermal maturity,mineral composition,diagenesis),the properties of fluids in pores(water,CH_(4),non-hydrocarbon gases),and geological conditions(temperature,pressure,preservation conditions)of the shale itself.For a particular basin or block,it is still challenging to define the main controlling factors,screen favorable exploration areas,and locate sweet spots.Compared to marine shales with extensive research and exploration data,lacustrine and marine-continental transitional shales are a further expanding area of investigation.Various methods have been developed to quantitatively characterize the in-situ gas content of shales,but all these methods have their own limitations,and more in-depth studies are needed to accurately evaluate and predict the in-situ gas content of shales,especially shales at deep depth.展开更多
This paper investigates a multi-component repairable system with double threshold control policy.The system is composed of n identical and independent components which operate simultaneously at the beginning,and it is...This paper investigates a multi-component repairable system with double threshold control policy.The system is composed of n identical and independent components which operate simultaneously at the beginning,and it is down when the number of operating components decreases to k−1(k≤n).When the number of failed components is less than the value L,the repairman repairs them with a low repair rate.The high repair rate is activated as soon as L failed components present,and continues until the number of failed components drops to the value N−1.Applying the matrix analytical method,the Laplace transform technique and the properties of the phase type distribution,various performance measures including the availability,the rate of occurrence of failures,and the reliability are derived in transient and stationary regimes.Further,numerical examples are reported to show the behaviour of the system.展开更多
In the article, the methods of processing and obtaining multicomponent raw materials were investigated with the properties of multicomponent threads obtained from fiber waste cluster enterprises in textile production,...In the article, the methods of processing and obtaining multicomponent raw materials were investigated with the properties of multicomponent threads obtained from fiber waste cluster enterprises in textile production, the interrelation of the components sorting composition. To solve the problem, we used the cause-effect relationship of information theory from the grid planning Matrix, solving the dependence of raw materials, physical and mechanical parameters and the established characteristics of the product. Empirical correlations were obtained on the nature and mechanism of the relationship between factors, which allowed the system to establish a theory of control and prediction of behavior. The methods of evaluation used in this study make it possible to expand the information base with respect to these indicators and to use them in the production of fabrics and threads with established characteristics.展开更多
This paper focuses on the numerical study of heat and moisture transfer in clothing assemblies,based on a multi-component and multiphase flow model which includes heat/moisture convection and conduction/diffusion as w...This paper focuses on the numerical study of heat and moisture transfer in clothing assemblies,based on a multi-component and multiphase flow model which includes heat/moisture convection and conduction/diffusion as well as phase change.A splitting semi-implicit finite volume method is proposed for solving a set of nonlinear convection-diffusion-reaction equations,in which the calculation of liquid water content absorbed by fiber is decoupled from the rest of the computation.The method maintains the conservation of air,vapor and heat flux(energy).Four types of clothing assemblies are investigated and comparison with experimental measurements are also presented.展开更多
The five-equation model of multi-component flows has been attracting much attention among researchers during the past twenty years for its potential in the study of the multi-component flows.In this paper,we employ a ...The five-equation model of multi-component flows has been attracting much attention among researchers during the past twenty years for its potential in the study of the multi-component flows.In this paper,we employ a second order finite volume method with minmod limiter in spatial discretization,which preserves local extrema of certain physical quantities and is thus capable of simulating challenging test problems without introducing non-physical oscillations.Moreover,to improve the numerical resolution of the solutions,the adaptive moving mesh strategy proposed in[Huazhong Tang,Tao Tang,Adaptive mesh methods for one-and two-dimensional hyperbolic conservation laws,SINUM,41:487-515,2003]is applied.Furthermore,the proposed method can be proved to be capable of preserving the velocity and pressure when they are initially constant,which is essential in material interface capturing.Finally,several classical numerical examples demonstrate the effectiveness and robustness of the proposed method.展开更多
An element decomposition method with variance strain stabilization(EDM-VSS) is proposed. In the present EDM-VSS, the quadrilateral element is first divided into four sub-triangular cells, and the local strains in sub-...An element decomposition method with variance strain stabilization(EDM-VSS) is proposed. In the present EDM-VSS, the quadrilateral element is first divided into four sub-triangular cells, and the local strains in sub-triangular cells are obtained using linear interpolation function. For each quadrilateral element, the strain of the whole quadrilateral is the weighted average value of the local strains, which means only one integration point is adopted to construct the stiffness matrix. The stabilization item of the stiffness matrix is constructed by variance of the local strains, which can eliminate the instability of the one-point integration formulation and largely increase the accuracy of the element. Compared with conventional full integration quadrilateral element, the EDM-VSS achieves more accurate results and expends much lower computational cost. More importantly, as no mapping or coordinate transformation is involved in the present EDM-VSS, the restriction on the conventional quadrilateral elements can be removed and problem domain can be discretized in more flexible ways. To verify the accuracy and stability of the present formulation, a number of numerical examples are studied to demonstrate the efficiency of the present EDM-VSS.展开更多
An electrocatalytic multicomponent cascade cross-coupling for the synthesis of chalcogenosulfonates has been established.This approach does not require the use of transition metals,acids,and external oxidants.The gent...An electrocatalytic multicomponent cascade cross-coupling for the synthesis of chalcogenosulfonates has been established.This approach does not require the use of transition metals,acids,and external oxidants.The gentle conditions and tolerance to a wide variety of functional groups permit the derivatization of complex indoles.展开更多
Objective: To establish a rapid, accurate and reliable analytical method for the simultaneous determination of four major anthraquinones in Polygoni Multiflori Radix(PMR) using single reference standard.Methods: The f...Objective: To establish a rapid, accurate and reliable analytical method for the simultaneous determination of four major anthraquinones in Polygoni Multiflori Radix(PMR) using single reference standard.Methods: The four components including emodin-8-O-β-D-(EMG), physcion-8-O-β-D-glucoside, emodin and physcion were separated on an ODS C18 column within 13 min and detected at 280 nm. Emodin was selected as the reference standard, and the response factor for each analyte with respect to emodin were calculated. Robustness were also tested including different columns, equipments, temperatures, detection wavelengths, and other chromatographic conditions which might influence stability of response factors.Results: The method was validated in terms of linearity(r^2> 0.9995), LOQs(0.820–3.05 ng/m L), LODs(0.180–0.920 ng/m L), precision,accuracy(95.8–103.6%, RSD < 2.80%) and stability. A total of 40 batches of PMR were analyzed and the results were found to have no statistically significant differences compared with those obtained using the external standard method.Conclusion: This work provided a single standard to determine multi-components method for quantitation of four anthraquinones in PMR,which could be applied in the quality control of this herbal drug.展开更多
基金Projects (51275138,51605016) supported by the National Natural Science Foundation of ChinaProject (12531109) supported by the Science Foundation of Heilongjiang Provincial Department of Education,ChinaProject supported by Research Start-up Funding of Fudan University,China
文摘For unacceptable computational efficiency and accuracy on the probabilistic analysis of multi-component system with multi-failure modes,this paper proposed multi-extremum response surface method(MERSM).MERSM model was established based on quadratic polynomial function by taking extremum response surface model as the sub-model of multi-response surface method.The dynamic probabilistic analysis of an aeroengine turbine blisk with two components,and their reliability of deformation and stress failures was obtained,based on thermal-structural coupling technique,by considering the nonlinearity of material parameters and the transients of gas flow,gas temperature and rotational speed.The results show that the comprehensive reliability of structure is 0.9904 when the allowable deformations and stresses of blade and disk are 4.78×10–3 m and 1.41×109 Pa,and 1.64×10–3 m and 1.04×109 Pa,respectively.Besides,gas temperature and rotating speed severely influence the comprehensive reliability of system.Through the comparison of methods,it is shown that the MERSM holds higher computational precision and speed in the probabilistic analysis of turbine blisk,and MERSM computational precision satisfies the requirement of engineering design.The efforts of this study address the difficulties on transients and multiple models coupling for the dynamic probabilistic analysis of multi-component system with multi-failure modes.
基金National Natural Science Foundation of China under Grant No.10735030Shanghai Leading Academic Discipline Project under Grant No.B412+1 种基金Natural Science Foundation of Zhejiang Province of China under Grant No.Y604056the Doctoral Foundation of Ningbo City under Grant No.2005A61030
文摘Painleve property of the （2＋1）-dimensional multi-component Broer-Kaup （BK） system is considered by using the standard Weiss Kruskal approaches. Applying the Clarkson and Kruskal （CK） direct method to the （2＋1）- dimensional multi-component BK system, some types of similarity reductions are obtained. By solving the reductions, one can get the solutions of the （2＋1）-dimensional multi-component BK system.
文摘Objective: to establish multi-components by single marker (QAMS) and HPlC method for the determination of four substances (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin and to provide experimental basis for the quality standard of Compound Yizhihao Granules. Methods: the sample treatment method was improved, and HPLC external standard method was established for the determination of four substances in Compound Yizhihao Granules. The chromatographic column was Wondersil C18 (4.6mm×250mm, 5μm), the flow rate was 1.0mL/min, the check wavelength was 245nm, the column temperature was 30℃, the sample was 20 μL, the mobile phase was acetonitrile-water. The relative correction factors (RCF) of (R, S) - Epigoitrin, Vitexicarpin, Artemisetin were determined with Indirubin as internal reference. The RCF was used to calculate the content of the substance under test, and then the content of the substance under test was determined by the external standard method to verify the feasibility of the multi-components by single marker. Results: the treatment method of the test sample was as follows: solid-liquid ratio was 1:5. Ultrasound was 45 min, trichloromethane extraction, and steam dry concentration with methanol constant volume. The results showed that the good linear ranges of (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin were 5.15-103 μ g / mL, 5.005-100.1 μ g / mL, 0.5-10 μ g / mL and 0.5115-10.23 μ g / mL, respectively. The average recoveries were 95.19%, 95.73%, 90.75%, 91.65%. The relative correction factors (RCF) of (R, S) - Epigoitrin, Vitexicarpin, Artemisetin were determined with Indirubin as internal reference was 0.2%, 0.6% and 0.3%. And the relative error of multi-components by single marker and external standard method was less than 1%. Conclusion: the multi-components by single marker method (QAMS) is simple, stable and can be used for the determination of multiple substances in Compound Yizhihao Granules.
基金Project(51335003)supported by the National Natural Science Foundation of ChinaProject(20111102110011)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘The fatigue life of aeroengine turbine disc presents great dispersion due to the randomness of the basic variables,such as applied load,working temperature,geometrical dimensions and material properties.In order to ameliorate reliability analysis efficiency without loss of reliability,the distributed collaborative response surface method(DCRSM) was proposed,and its basic theories were established in this work.Considering the failure dependency among the failure modes,the distributed response surface was constructed to establish the relationship between the failure mode and the relevant random variables.Then,the failure modes were considered as the random variables of system response to obtain the distributed collaborative response surface model based on structure failure criterion.Finally,the given turbine disc structure was employed to illustrate the feasibility and validity of the presented method.Through the comparison of DCRSM,Monte Carlo method(MCM) and the traditional response surface method(RSM),the results show that the computational precision for DCRSM is more consistent with MCM than RSM,while DCRSM needs far less computing time than MCM and RSM under the same simulation conditions.Thus,DCRSM is demonstrated to be a feasible and valid approach for improving the computational efficiency of reliability analysis for aeroengine turbine disc fatigue life with multiple random variables,and has great potential value for the complicated mechanical structure with multi-component and multi-failure mode.
文摘Four components have been reacted in water and in the presence of N-morpholine yielded pyrnopyrazole as a simple substrate for novel N2-acyclonucleoside derivatives of fused pyranopyrazole. The sodium salt of fused pyranopyrazole reacted with halo alcohols led to the formation of new scaffolds from fused pyranopyrazole derivatives. All newly prepared compounds are characterized spectroscopically.
基金Funding Open Access funding enabled and organized by Projekt DEAL.When preparing this manuscript,the authors have kept the COPE guidelines on how to deal with potential acts of misconduct.The research leading to these results received funding from Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)through the project SFB-TRR 75 with the project number 84292822the DFG under Germanys Excellence Strategy-EXC2075with the project number390740016.
文摘Understanding the dynamics of phase boundaries in fluids requires quantitative knowledge about the microscale processes at the interface.We consider the sharp-interface motion of the compressible two-component flow and propose a heterogeneous multiscale method(HMM)to describe the flow fields accurately.The multiscale approach combines a hyperbolic system of balance laws on the continuum scale with molecular-dynamics(MD)simulations on the microscale level.Notably,the multiscale approach is necessary to compute the interface dynamics because there is—at present—no closed continuum-scale model.The basic HMM relies on a moving-mesh finite-volume method and has been introduced recently for the compressible one-component flow with phase transitions by Magiera and Rohde in(J Comput Phys 469:111551,2022).To overcome the numerical complexity of the MD microscale model,a deep neural network is employed as an efficient surrogate model.The entire approach is finally applied to simulate droplet dynamics for argon-methane mixtures in several space dimensions.To our knowledge,such compressible two-phase dynamics accounting for microscale phase-change transfer rates have not yet been computed.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12272269, 11972257,11832014 and 11472193)the Shanghai Pilot Program for Basic Researchthe Shanghai Gaofeng Project for University Academic Program Development。
文摘Understanding the effects of point liquid loading on transversely isotropic poroelastic media is crucial for advancing geomechanics and biomechanics, where precise modeling of fluid-structure interactions is essential. This paper presents a comprehensive analysis of infinite transversely isotropic poroelasticity under a fluid source, based on Biot's theory, aiming to uncover new and previously unexplored insights in the literature. We begin our study by deriving a general solution for fluid-saturated, transversely isotropic poroelastic materials in terms of harmonic functions that satisfy sixth-order homogeneous partial differential equations, using potential theory and Almansi's theorem. Based on these general solutions and potential functions, we construct a Green's function for a point fluid source, introducing three new harmonic functions with undetermined constants. These constants are determined by enforcing continuity and equilibrium conditions. Substituting these into the general solution yields fundamental solutions for poroelasticity that provide crucial support for a wide range of project problems. Numerical results and comparisons with existing literature are provided to illustrate physical mechanisms through contour plots. Our observations reveal that all components tend to zero in the far field and become singular at the concentrated source. Additionally, the contours exhibit rapid changes near the point fluid source but display gradual variations at a distance from it. These findings highlight the intricate behavior of the system under point liquid loading, offering valuable insights for further research and practical applications.
基金financial support provided by the National Natural Science Foundation of China(22207063)111 Project(D20015),Hubei Provincial Central Government Guided Local Science and Technology Development Project(2024BSB016)+1 种基金Natural Science Research Project of Yichang City(A23-2-002)the Opening Funding of Hubei Key Laboratory of Natural Products Research and Development,China Three Gorges University(2024NPRD03,2024NPRD04,2024NPRD05).
文摘Herein,we developed a tertiary amine-catalyzed stereoretentive multi-component cascade reaction featuring an amidation/[4+1]annulation/decarboxylation/Curtius rearrangement/[2+n]annulation sequence.This metal-free and step-economic method provided a broad range of cyclic ureas/urethanes in green solvent under mild conditions without employing explosive and toxic reagents.Importantly,this reaction generated isocyanates in situ under catalytic conditions via a decarboxylation/Curtius rearrangement process of dioxazolones.
基金Project(41372329) supported by the National Natural Science Foundation of ChinaProject(2014CB744701) supported by the National Basic Research Program of China
文摘To predict the soil-water characteristic curve(i.e.SWCC)of natural and remoulded Malan loess from soil physical properties,one-point methods for determining the SWCC that are much simpler than experimental methods are proposed.The predicted SWCC is presented in the form of the BRUTSAERT equation,in which the four model parameters can be estimated from soil physical properties using the best correlations obtained in the present study along with one measured data point.The proposed one-point methods are validated using the measured SWCC data reported in the literature.The results of validation studies suggest that the proposed one-point methods can provide reasonable prediction of the SWCC for natural and remoulded Malan loess.The measured data point should be within the transition zone;the measured suction is suggested between25to100kPa for natural loess,while between100to500kPa for remoulded loess.
基金Supported by the National Natural Science Foundation of China (Grant No.50401013)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of the People's Republic of China
文摘By using the phase field model for the solidification of multi-component alloys and coupling with real thermodynamic data, the dendritic morphology transition and the dendritic micro-segregation of Ni-Al-Nb ternary alloys are simulated in two cases, i.e., varying the alloy composition at a fixed under-cooling and varying the undercooling at a fixed alloy composition. The simulated results indicate that with the increase of the dimensionless undercooling U (U=ΔT/ΔT0, where ΔT is the undercooling and ΔT0 the temperature interval between the solidus and liquidus), the dendritic morphology transfers from dendritic to globular growth in both cases. As to the dendritic micro-segregation, both cases present a regularity of increasing at first and then decreasing.
基金supported by the National Natural Science Foundation of China(U19B6003-03-01)the Science and Technology Department of Shanxi Province,China(20201101003)the National Natural Science Foundation of China(42030804).
文摘In the past 15 years,the shale gas revolution and large-scale commercial developments in the United States have driven the exploration and development of shale plays worldwide.Among many factors affecting shale gas exploration potential,the gas-bearing properties of shale(quantity,storage state,composition)and their controlling factors are the essential research attracting wide attention in the academic community.This paper reviews the research progress on the retention mechanism,influencing factors,and evaluation methods for resource potential of the shale gas system,and proposes further research directions.Sorption is the main mechanism of gas retention in organic-rich shales;the gas is mainly stored in nanopores of shale in free and sorption states.The presence of water and nonhydrocarbon gases in pores can complicate the process and mechanism of methane(CH4)sorption,and the related theoretical models still need further development.The in-situ gas content and gasbearing properties of shale are governed by the geological properties(organic matter abundance,kerogen type,thermal maturity,mineral composition,diagenesis),the properties of fluids in pores(water,CH_(4),non-hydrocarbon gases),and geological conditions(temperature,pressure,preservation conditions)of the shale itself.For a particular basin or block,it is still challenging to define the main controlling factors,screen favorable exploration areas,and locate sweet spots.Compared to marine shales with extensive research and exploration data,lacustrine and marine-continental transitional shales are a further expanding area of investigation.Various methods have been developed to quantitatively characterize the in-situ gas content of shales,but all these methods have their own limitations,and more in-depth studies are needed to accurately evaluate and predict the in-situ gas content of shales,especially shales at deep depth.
基金This research was supported by the National Natural Science Foundation of China(No.71571127)the funding of V.C.&V.R.Key Lab of Sichuan Province(SCVCVR2019.05VS)the Sichuan Science and Technology Program(Nos.2020YFS0318,2019YFS0155,2019YFS0146,2020YFG0430,2020YFS0307).
文摘This paper investigates a multi-component repairable system with double threshold control policy.The system is composed of n identical and independent components which operate simultaneously at the beginning,and it is down when the number of operating components decreases to k−1(k≤n).When the number of failed components is less than the value L,the repairman repairs them with a low repair rate.The high repair rate is activated as soon as L failed components present,and continues until the number of failed components drops to the value N−1.Applying the matrix analytical method,the Laplace transform technique and the properties of the phase type distribution,various performance measures including the availability,the rate of occurrence of failures,and the reliability are derived in transient and stationary regimes.Further,numerical examples are reported to show the behaviour of the system.
文摘In the article, the methods of processing and obtaining multicomponent raw materials were investigated with the properties of multicomponent threads obtained from fiber waste cluster enterprises in textile production, the interrelation of the components sorting composition. To solve the problem, we used the cause-effect relationship of information theory from the grid planning Matrix, solving the dependence of raw materials, physical and mechanical parameters and the established characteristics of the product. Empirical correlations were obtained on the nature and mechanism of the relationship between factors, which allowed the system to establish a theory of control and prediction of behavior. The methods of evaluation used in this study make it possible to expand the information base with respect to these indicators and to use them in the production of fabrics and threads with established characteristics.
基金The research of Ye and Sun was supported in part by a grant from CityU(7001926)The research of Huang is supported by the Natural Science and Engineering Council(NSERC)and the Mathematics of Information Technology and Complex Systems(MITACS)of Canada.The research of Fan is supported by Hong Kong Polytechnic University(Project No.G-U165).
文摘This paper focuses on the numerical study of heat and moisture transfer in clothing assemblies,based on a multi-component and multiphase flow model which includes heat/moisture convection and conduction/diffusion as well as phase change.A splitting semi-implicit finite volume method is proposed for solving a set of nonlinear convection-diffusion-reaction equations,in which the calculation of liquid water content absorbed by fiber is decoupled from the rest of the computation.The method maintains the conservation of air,vapor and heat flux(energy).Four types of clothing assemblies are investigated and comparison with experimental measurements are also presented.
基金The research of Yaguang Gu is funded by China Postdoctoral Science Foundation(2021M703040)The research of Dongmi Luo is supported by the National Natural Science Foundation of China(12101063)+3 种基金The research of Zhen Gao is supported by the National Natural Science Foundation of China(11871443)Shandong Provincial Qingchuang Science and Technology Project(2019KJI002)Fundamental Research Funds for the Central Universities(202042004)The research of Yibing Chen is supported by National Key Project(GJXM92579).
文摘The five-equation model of multi-component flows has been attracting much attention among researchers during the past twenty years for its potential in the study of the multi-component flows.In this paper,we employ a second order finite volume method with minmod limiter in spatial discretization,which preserves local extrema of certain physical quantities and is thus capable of simulating challenging test problems without introducing non-physical oscillations.Moreover,to improve the numerical resolution of the solutions,the adaptive moving mesh strategy proposed in[Huazhong Tang,Tao Tang,Adaptive mesh methods for one-and two-dimensional hyperbolic conservation laws,SINUM,41:487-515,2003]is applied.Furthermore,the proposed method can be proved to be capable of preserving the velocity and pressure when they are initially constant,which is essential in material interface capturing.Finally,several classical numerical examples demonstrate the effectiveness and robustness of the proposed method.
基金supported by the National Natural Science Foundation of China(Grant Nos.11472101 and 61232014)Postdoctoral Science Foundation of China(Grant No.2013M531780)the National Laboratory for Electric Vehicles Foundations
文摘An element decomposition method with variance strain stabilization(EDM-VSS) is proposed. In the present EDM-VSS, the quadrilateral element is first divided into four sub-triangular cells, and the local strains in sub-triangular cells are obtained using linear interpolation function. For each quadrilateral element, the strain of the whole quadrilateral is the weighted average value of the local strains, which means only one integration point is adopted to construct the stiffness matrix. The stabilization item of the stiffness matrix is constructed by variance of the local strains, which can eliminate the instability of the one-point integration formulation and largely increase the accuracy of the element. Compared with conventional full integration quadrilateral element, the EDM-VSS achieves more accurate results and expends much lower computational cost. More importantly, as no mapping or coordinate transformation is involved in the present EDM-VSS, the restriction on the conventional quadrilateral elements can be removed and problem domain can be discretized in more flexible ways. To verify the accuracy and stability of the present formulation, a number of numerical examples are studied to demonstrate the efficiency of the present EDM-VSS.
基金funding supports from Guizhou Provincial Basic Research Program(Natural Science)(No.QianKeHeJiChu-ZK[2024]YiBan086)the starting grant of Guizhou University[(2023)5].
文摘An electrocatalytic multicomponent cascade cross-coupling for the synthesis of chalcogenosulfonates has been established.This approach does not require the use of transition metals,acids,and external oxidants.The gentle conditions and tolerance to a wide variety of functional groups permit the derivatization of complex indoles.
基金supported by the traditional Chinese Medicine Industry Special Scientific Research (No.201307002)the National New Drug Innovation Major Project of China (No.2012ZX09304005002)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Objective: To establish a rapid, accurate and reliable analytical method for the simultaneous determination of four major anthraquinones in Polygoni Multiflori Radix(PMR) using single reference standard.Methods: The four components including emodin-8-O-β-D-(EMG), physcion-8-O-β-D-glucoside, emodin and physcion were separated on an ODS C18 column within 13 min and detected at 280 nm. Emodin was selected as the reference standard, and the response factor for each analyte with respect to emodin were calculated. Robustness were also tested including different columns, equipments, temperatures, detection wavelengths, and other chromatographic conditions which might influence stability of response factors.Results: The method was validated in terms of linearity(r^2> 0.9995), LOQs(0.820–3.05 ng/m L), LODs(0.180–0.920 ng/m L), precision,accuracy(95.8–103.6%, RSD < 2.80%) and stability. A total of 40 batches of PMR were analyzed and the results were found to have no statistically significant differences compared with those obtained using the external standard method.Conclusion: This work provided a single standard to determine multi-components method for quantitation of four anthraquinones in PMR,which could be applied in the quality control of this herbal drug.
