Cone penetration testing(CPT)and its variant with pore pressure measurements(CPTu)are versatile tools that have been traditionally used for in situ geotechnical site investigations.These investigations are among the m...Cone penetration testing(CPT)and its variant with pore pressure measurements(CPTu)are versatile tools that have been traditionally used for in situ geotechnical site investigations.These investigations are among the most challenging yet indispensable tasks,providing a crucial reference for infrastructure planning,design and construction.However,data obtained through the CPT/CPTu testing often exhibit significant variability,even at closely spaced test points.This variability is primarily attributed to the complex mineral compositions and sedimentary process of the Quaternary sediments.Problems induced by the scattering data include the difficulties in estimating the shear strength of the sediments and determining the appropriate bearing stratum for pile foundations.In this paper,the conventional interpretation methods of the CPT/CPTu data are enhanced with sedimentary facies knowledge.The geotechnical investigation mainly involves 42 CPTu tests(39 essential data sets available)and 4 boring samples.Sediment types are interpreted from the CPTu data and calibrated by the nearby boring samples.Sedimentary facies are derived from the interpreted sequence stratigraphy,for which the interpretation skills are summarized in the form of characteristic curves of the CPTu data.Scattering distribution of the sediment types and their mechanical parameters are well explained by the sedimentary facies.The sediments are then categorized into a few groups by their sedimentary facies,resulting in reduced uncertainties and scattering in terms of shear strength.Bearing stratum of pile foundations is also suggested based on the sedimentary regulations.展开更多
The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock,thereby affecting its overall stability.It is therefore essential to study the stress and strain...The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock,thereby affecting its overall stability.It is therefore essential to study the stress and strain fields in the rocks surrounding the submarine tunnel by considering the coupled effect of strainsoftening and seepage.However,the evolution equation for the hydro-mechanical parameters in the existing fully coupled solution is a uniform equation that is unable to reproduce the characteristics of rock mass in practice.In this study,an updated numerical procedure for the submarine tunnel is derived by coupling strain-softening and seepage effect based on the experimental results.According to the hydro-mechanical coupling theory,the hydro-mechanical parameters such as elastic modulus,Poisson's ratio,Biot's coefficient and permeability coefficient of rocks are characterized by the fitting equations derived from the experimental data.Then,the updated numerical procedure is deduced with the governing equations,boundary conditions,seepage equations and fitting equations.The updated numerical procedure is verified accurately compared with the previous analytical solution.By utilizing the updated numerical procedure,the characteristics of stress field and the influences of initial pore water pressure,Biot's coefficient,and permeability coefficient on the stress,displacement and water-inflow of the surrounding rocks are discussed.Regardless of the variations in hydro-mechanical parameters,the stress distribution has a similar trend.The initial permeability coefficient exerts the most significant influence on the stress field.With the increases in initial pore water pressure and Biot's coefficient,the plastic region expands,and the water-inflow and displacement increase accordingly.Given the fact that the stability of the tunnel is more sensitive to the seepage force controlled by the hydraulic parameters,it is suggested to dewater the ground above the submarine tunnel to control the initial pore water pressure.展开更多
Objective:To investigate the relationship between the levels of plasma adrenaline and norepinephrine and gene polymorphism ofβ1 adrenergic receptor G1165 C in children with enterovirus 71(EV71)infection in hand foot ...Objective:To investigate the relationship between the levels of plasma adrenaline and norepinephrine and gene polymorphism ofβ1 adrenergic receptor G1165 C in children with enterovirus 71(EV71)infection in hand foot and mouth disease(HFMD).Methods:The polymerase chain reaction(PCR)was used to detect the expression of gene polymorphism ofβ1 adrenergic receptor G1165 C in vitro.The levels of plasma adrenaline and norepinephrine were measured by enzyme-linked immunosorbent assay(ELISA).Results:The plasma norepinephrine level of severe group was significantly higher than the mild group in children with EV71 infection in HFMD(P<0.05);however,the levels of plasma adrenalinein in two groups had no statistical differences(P>0.05);There was no significant difference in the distribution ofβ1 adrenergic receptor G1165 C genotype and allele between EV71 infection group and healthy control group(P>0.05).Further analysis of EV71 infection group by dividing it into mild and severe groups showed that there was no significant difference in the distribution of genotype and allele between these two groups as well(P>0.05).There was no significant difference in the levels of epinephrine and norepinephrine in different genotypes of EV71 infection group(P>0.05),and in the levels of plasma epinephrine and norepinephrine in the mild and severe groups(P>0.05).Conclusions:As the disease gets worse,the plasma norepinephrine level has a rising trend in children with EV71 infection in HFMD,which is an important indicator to evaluate the progress of the disease.However,the gene polymorphism of eptor G1165 C have no significant correlation,not only with the susceptibility and severitβ1 adrenergic recy of EV71 infection in hand,foot and mouth disease,but also with the levels of catecholamine.展开更多
Outgoing waves arising from high-velocity impacts between soil and structure can be reflected by the conventional truncated boundaries.Absorbing boundary conditions(ABCs),to attenuate the energy of the outward waves,a...Outgoing waves arising from high-velocity impacts between soil and structure can be reflected by the conventional truncated boundaries.Absorbing boundary conditions(ABCs),to attenuate the energy of the outward waves,are necessary to ensure the proper representation of the kinematic field and the accurate quantification of impact forces.In this paper,damping layer and dashpot ABCs are implemented in the material point method(MPM)with slight adjustments.Benchmark scenarios of different dynamic problems are modelled with the ABCs configured.Feasibility of the ABCs is assessed through the velocity fluctuations at specific observation points and the impact force fluctuations on the structures.The impact forces predicted by the MPM with ABCs are verified by comparison with those estimated using a computational fluid dynamics approach.展开更多
The LaCo_(0.94)Pt_(0.06)O_(3) catalyst is reduced under 5% H_(2)/Ar at different temperatures to get Pt/LaCoO_(3) with high catalytic activity for soot oxidation.Transmission electron microscopy(TEM),scanning electron...The LaCo_(0.94)Pt_(0.06)O_(3) catalyst is reduced under 5% H_(2)/Ar at different temperatures to get Pt/LaCoO_(3) with high catalytic activity for soot oxidation.Transmission electron microscopy(TEM),scanning electron microscopy(SEM),X-ray diffraction(XRD),Brunauer-Emmett-Teller method(BET),X-ray photoelectron spectroscopy(XPS),H_(2)-temperature programmed reduction(H_(2)-TPR),O_(2)-temperature programmed desorption(O_(2)-TPD) and thermogravimetric analysis(TGA) were used to study the physicochemical properties of the catalyst.SEM and TEM results indicate that Pt nanoparticles(<10 nm) are grown homogeneously on the surface of the LaCoO_(3) matrix after in-situ reduction.XRD shows that the reduced catalyst has a high symmetrical structure.TGA results indicate that all reduced catalysts exhibit an excellent activity,especially the catalyst reduced at 350℃(T_(10)=338℃,T_(50)=393℃,T_(90)=427℃).And perovskite is the primary active component.According to XPS study,the high symmetrical structure benefits the mobility of oxygen vacancy,and Pt nanoparticles induce the oxygen vacancy to move to its adjacent situation,resulting in more adsorbed oxygen on the surface of the reduced catalyst and increasing the activity.The possible reaction principle is also proposed.展开更多
In this work,the Ag loaded Ce-based catalyst was synthesized(by the sol-gel method)and its performance was studied by TG,H2-TPR,XRD,SEM,TEM,BET and XPS.The results show that Ag nanoparticles be successfully loaded ont...In this work,the Ag loaded Ce-based catalyst was synthesized(by the sol-gel method)and its performance was studied by TG,H2-TPR,XRD,SEM,TEM,BET and XPS.The results show that Ag nanoparticles be successfully loaded onto the CeO2 surface and the relative content of Ag nanoparticles is about 10.22 wt.%close to the theoretical value(10%).XPS shows that Ag nanoparticles induce a great number of oxygen vacancies in the CeO2 lattice through the electronic transfer,and H2-TPR indicates that the Ag-assisted CeO2 catalyst exhibits a better reduction performance and Ag nanoparticles can promote O^- transform into O2^-.The catalytic activity for soot oxidation was studied by TG under air atmosphere and the activity was found to be obviously enhanced when Ag nanoparticles be load on the surface of CeO2(T10=386℃,79o=472.5℃,Tm=431℃).The reaction mechanism was also presented and Oi species is regarded as the determinant factor for the catalytic activity.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42272328 and 52108356).
文摘Cone penetration testing(CPT)and its variant with pore pressure measurements(CPTu)are versatile tools that have been traditionally used for in situ geotechnical site investigations.These investigations are among the most challenging yet indispensable tasks,providing a crucial reference for infrastructure planning,design and construction.However,data obtained through the CPT/CPTu testing often exhibit significant variability,even at closely spaced test points.This variability is primarily attributed to the complex mineral compositions and sedimentary process of the Quaternary sediments.Problems induced by the scattering data include the difficulties in estimating the shear strength of the sediments and determining the appropriate bearing stratum for pile foundations.In this paper,the conventional interpretation methods of the CPT/CPTu data are enhanced with sedimentary facies knowledge.The geotechnical investigation mainly involves 42 CPTu tests(39 essential data sets available)and 4 boring samples.Sediment types are interpreted from the CPTu data and calibrated by the nearby boring samples.Sedimentary facies are derived from the interpreted sequence stratigraphy,for which the interpretation skills are summarized in the form of characteristic curves of the CPTu data.Scattering distribution of the sediment types and their mechanical parameters are well explained by the sedimentary facies.The sediments are then categorized into a few groups by their sedimentary facies,resulting in reduced uncertainties and scattering in terms of shear strength.Bearing stratum of pile foundations is also suggested based on the sedimentary regulations.
基金supported by the National Natural Science Foundation of China(Grant Nos.52279118 and U21A20159)Sub-project of National Key Research and Development(Grant No.2023YFC3007403).
文摘The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock,thereby affecting its overall stability.It is therefore essential to study the stress and strain fields in the rocks surrounding the submarine tunnel by considering the coupled effect of strainsoftening and seepage.However,the evolution equation for the hydro-mechanical parameters in the existing fully coupled solution is a uniform equation that is unable to reproduce the characteristics of rock mass in practice.In this study,an updated numerical procedure for the submarine tunnel is derived by coupling strain-softening and seepage effect based on the experimental results.According to the hydro-mechanical coupling theory,the hydro-mechanical parameters such as elastic modulus,Poisson's ratio,Biot's coefficient and permeability coefficient of rocks are characterized by the fitting equations derived from the experimental data.Then,the updated numerical procedure is deduced with the governing equations,boundary conditions,seepage equations and fitting equations.The updated numerical procedure is verified accurately compared with the previous analytical solution.By utilizing the updated numerical procedure,the characteristics of stress field and the influences of initial pore water pressure,Biot's coefficient,and permeability coefficient on the stress,displacement and water-inflow of the surrounding rocks are discussed.Regardless of the variations in hydro-mechanical parameters,the stress distribution has a similar trend.The initial permeability coefficient exerts the most significant influence on the stress field.With the increases in initial pore water pressure and Biot's coefficient,the plastic region expands,and the water-inflow and displacement increase accordingly.Given the fact that the stability of the tunnel is more sensitive to the seepage force controlled by the hydraulic parameters,it is suggested to dewater the ground above the submarine tunnel to control the initial pore water pressure.
基金supported by the Research Projects of Hainan Province Health Planning Industry(grant numbers:2012ZD-03)
文摘Objective:To investigate the relationship between the levels of plasma adrenaline and norepinephrine and gene polymorphism ofβ1 adrenergic receptor G1165 C in children with enterovirus 71(EV71)infection in hand foot and mouth disease(HFMD).Methods:The polymerase chain reaction(PCR)was used to detect the expression of gene polymorphism ofβ1 adrenergic receptor G1165 C in vitro.The levels of plasma adrenaline and norepinephrine were measured by enzyme-linked immunosorbent assay(ELISA).Results:The plasma norepinephrine level of severe group was significantly higher than the mild group in children with EV71 infection in HFMD(P<0.05);however,the levels of plasma adrenalinein in two groups had no statistical differences(P>0.05);There was no significant difference in the distribution ofβ1 adrenergic receptor G1165 C genotype and allele between EV71 infection group and healthy control group(P>0.05).Further analysis of EV71 infection group by dividing it into mild and severe groups showed that there was no significant difference in the distribution of genotype and allele between these two groups as well(P>0.05).There was no significant difference in the levels of epinephrine and norepinephrine in different genotypes of EV71 infection group(P>0.05),and in the levels of plasma epinephrine and norepinephrine in the mild and severe groups(P>0.05).Conclusions:As the disease gets worse,the plasma norepinephrine level has a rising trend in children with EV71 infection in HFMD,which is an important indicator to evaluate the progress of the disease.However,the gene polymorphism of eptor G1165 C have no significant correlation,not only with the susceptibility and severitβ1 adrenergic recy of EV71 infection in hand,foot and mouth disease,but also with the levels of catecholamine.
基金the Key Science and Technology Plan of Power China Huadong Engineering Corporation(No.KY2018-ZD-01)China and the National Natural Science Foundations of China(No.51909248)。
文摘Outgoing waves arising from high-velocity impacts between soil and structure can be reflected by the conventional truncated boundaries.Absorbing boundary conditions(ABCs),to attenuate the energy of the outward waves,are necessary to ensure the proper representation of the kinematic field and the accurate quantification of impact forces.In this paper,damping layer and dashpot ABCs are implemented in the material point method(MPM)with slight adjustments.Benchmark scenarios of different dynamic problems are modelled with the ABCs configured.Feasibility of the ABCs is assessed through the velocity fluctuations at specific observation points and the impact force fluctuations on the structures.The impact forces predicted by the MPM with ABCs are verified by comparison with those estimated using a computational fluid dynamics approach.
基金Project supported by the Joint Funds of the National Natural Science Foundation of China(U20A20132)。
文摘The LaCo_(0.94)Pt_(0.06)O_(3) catalyst is reduced under 5% H_(2)/Ar at different temperatures to get Pt/LaCoO_(3) with high catalytic activity for soot oxidation.Transmission electron microscopy(TEM),scanning electron microscopy(SEM),X-ray diffraction(XRD),Brunauer-Emmett-Teller method(BET),X-ray photoelectron spectroscopy(XPS),H_(2)-temperature programmed reduction(H_(2)-TPR),O_(2)-temperature programmed desorption(O_(2)-TPD) and thermogravimetric analysis(TGA) were used to study the physicochemical properties of the catalyst.SEM and TEM results indicate that Pt nanoparticles(<10 nm) are grown homogeneously on the surface of the LaCoO_(3) matrix after in-situ reduction.XRD shows that the reduced catalyst has a high symmetrical structure.TGA results indicate that all reduced catalysts exhibit an excellent activity,especially the catalyst reduced at 350℃(T_(10)=338℃,T_(50)=393℃,T_(90)=427℃).And perovskite is the primary active component.According to XPS study,the high symmetrical structure benefits the mobility of oxygen vacancy,and Pt nanoparticles induce the oxygen vacancy to move to its adjacent situation,resulting in more adsorbed oxygen on the surface of the reduced catalyst and increasing the activity.The possible reaction principle is also proposed.
文摘In this work,the Ag loaded Ce-based catalyst was synthesized(by the sol-gel method)and its performance was studied by TG,H2-TPR,XRD,SEM,TEM,BET and XPS.The results show that Ag nanoparticles be successfully loaded onto the CeO2 surface and the relative content of Ag nanoparticles is about 10.22 wt.%close to the theoretical value(10%).XPS shows that Ag nanoparticles induce a great number of oxygen vacancies in the CeO2 lattice through the electronic transfer,and H2-TPR indicates that the Ag-assisted CeO2 catalyst exhibits a better reduction performance and Ag nanoparticles can promote O^- transform into O2^-.The catalytic activity for soot oxidation was studied by TG under air atmosphere and the activity was found to be obviously enhanced when Ag nanoparticles be load on the surface of CeO2(T10=386℃,79o=472.5℃,Tm=431℃).The reaction mechanism was also presented and Oi species is regarded as the determinant factor for the catalytic activity.
