This paper provides a systematic evaluation of the ability of 12 Earth System Models(ESMs)participating in the Coupled Model Intercomparison Project Phase 6(CMIP6)to simulate the spatial inhomogeneity of the atmospher...This paper provides a systematic evaluation of the ability of 12 Earth System Models(ESMs)participating in the Coupled Model Intercomparison Project Phase 6(CMIP6)to simulate the spatial inhomogeneity of the atmospheric carbon dioxide(CO_(2))concentration.The multi-model ensemble mean(MME)can reasonably simulate the increasing trend of CO_(2) concentration from 1850 to 2014,compared with the observation data from the Scripps CO_(2) Program and CMIP6 prescribed data,and improves upon the CMIP5 MME CO_(2) concentration(which is overestimated after 1950).The growth rate of CO_(2) concentration in the northern hemisphere(NH)is higher than that in the southern hemisphere(SH),with the highest growth rate in the mid-latitudes of the NH.The MME can also reasonably simulate the seasonal amplitude of CO_(2) concentration,which is larger in the NH than in the SH and grows in amplitude after the 1950s(especially in the NH).Although the results of the MME are reasonable,there is a large spread among ESMs,and the difference between the ESMs increases with time.The MME results show that regions with relatively large CO_(2) concentrations(such as northern Russia,eastern China,Southeast Asia,the eastern United States,northern South America,and southern Africa)have greater seasonal variability and also exhibit a larger inter-model spread.Compared with CMIP5,the CMIP6 MME simulates an average spatial distribution of CO_(2) concentration that is much closer to the site observations,but the CMIP6-inter-model spread is larger.The inter-model differences of the annual means and seasonal cycles of atmospheric CO_(2) concentration are both attributed to the differences in natural sources and sinks of CO_(2) between the simulations.展开更多
The horizontal continuous casting process,the initial step in TP2 copper tubular processing,directly determines the microstructure and properties of copper tubular.However,the process parameters of the continuous cast...The horizontal continuous casting process,the initial step in TP2 copper tubular processing,directly determines the microstructure and properties of copper tubular.However,the process parameters of the continuous casting characterize time variation,multiple disturbances and strong coupling.As a consequence,their influence on a casting billet is difficult to be determined.Due to the above issues,the common factor and special factor analysis of the factor analysis model were used in this study,and the casting experiment and billet metallographic experiment were carried out to diagnose and analyze the reason of the microstructure inhomogeneity.The multiple process parameters were studied and classified using common factor analysis,2 the cast billets with abnormal microstructures were identified by GT^(2) statistics,and the most important factors affecting the microstructural homogeneity were found by special factor analysis.The calculated and experimental results show that the principal parameters influencing the inhomogeneity of solidified microstructure are the primary inlet water pressure and the primary outlet water temperature.According to the consequence of the above investigation,the inhomogeneity of the copper billet microstructure can be effectively improved when the process parameters are controlled and adjusted.展开更多
The tensile tests of the extruded ZK60 Mg containing a longitudinal weld seam were carried out at room and elevated temperatures, and the effects of induced microstructure inhomogeneity on tensile deformation behavior...The tensile tests of the extruded ZK60 Mg containing a longitudinal weld seam were carried out at room and elevated temperatures, and the effects of induced microstructure inhomogeneity on tensile deformation behavior was clarified. The results show that the deformation mode, dynamic recrystallization(DRX), texture evolution and mechanical properties are strongly affected by the longitudinal weld seam,temperature, and loading direction. The room temperature(RT) deformation of welding zone is controlled by the dislocation slips with the association of some twins, while twinning plays significant roles in the accommodation of c-axis strain of the coarse grains on matrix zone.The deformation at RT stretched along extrusion direction(ED) and transverse direction(TD) are controlled by basal slip/twinning and basal slip/prismatic slip/twinning, respectively. During high temperature tension, the dislocation cross slip of pyramidal slip is activated, and grain boundary sliding occurred in welding zone, leading to the superplastic behavior. With the increase of tensile temperature, the predominant DRX mode is transformed from continuous DRX to discontinuous DRX. Moreover, the basal poles of the grains spread from TD towards ED with the decrease of maximum pole intensity when stretched along ED, while non-basal textures are transformed to (10-10) fiber texture when stretched along TD. The slip-dominated flow is seen during RT tension along ED, while twinning becomes predominant during RT tension along TD. The fine grain structure causes the superior RT tensile properties along ED of welding zone with ultimate tensile strength of 315 MPa and elongation to failure of 13.8%. With the increase of tensile temperature, the slipping-dominated deformation is transformed into twinning-dominated, causing the decrease of strength and increase of elongation.展开更多
We prove that the interior stresses within both a non-parabolic open inhomogeneity and another interacting non-elliptical closed inhomogeneity can still remain constant when the matrix is simultaneously under the acti...We prove that the interior stresses within both a non-parabolic open inhomogeneity and another interacting non-elliptical closed inhomogeneity can still remain constant when the matrix is simultaneously under the action of a screw dislocation and uniform remote anti-plane stresses.The constancy of interior stresses is realized through the construction of a conformal mapping function for the doubly connected domain occupied by the surrounding matrix.The mapping function is endowed with the information describing the screw dislocation via the incorporation of two specifically defined logarithmic terms.The constant interior stress fields are observed to be independent of the specific open and closed shapes of the two inhomogeneities and the existence of the screw dislocation.In contrast,the existence of the neighboring screw dislocation significantly affects the open and closed shapes of the two inhomogeneities.展开更多
A theoretical model was suggested which describes the generation of the misfit dislocation dipole in the system of the viscoelastic matrix containing a circular stiff nanoscale inhomogeneity.The critical condition of ...A theoretical model was suggested which describes the generation of the misfit dislocation dipole in the system of the viscoelastic matrix containing a circular stiff nanoscale inhomogeneity.The critical condition of misfit dislocation dipole and the solution of equilibrium position were given.The influence of the ratio of shear modulus,the misfit strain and viscosity on the equilibrium of the dislocation and critical parameter of inhomogeneity was investigated.The result shows that the equilibrium position de increases with the increase of the ratio of original shear modulus and the effect decreases with the increase of viscosity of matrix.Along with the increase of viscosity of matrix,de first increases and then decreases and possesses maximum value when t=0.3τ and tends to a stable value when t≥1.0τ.Along with the increase of viscosity of matrix,Rc first decreases and then increases and possesses minimum value when t=0.3τ and tends to a stable value when t≥1.0τ.展开更多
Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surf...Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.展开更多
The Gurtin-Murdoch model has found wide applications in analyzing the mechanical behaviors of nanocomposites with surface/interface effect. In the existing literature, the matrix is usually assumed to be infinite and ...The Gurtin-Murdoch model has found wide applications in analyzing the mechanical behaviors of nanocomposites with surface/interface effect. In the existing literature, the matrix is usually assumed to be infinite and the surface/interface effect is considered only at the inhomogeneity-matrix interface. This assumption is indeed valid as the matrix is usually at macroscale rather than nanoscale. However, if the size of the matrix decreases to the nanoscale too, the surface/interface effect will have to be considered at the outer boundary of the matrix. In this paper, the plane deformation of a circular nano-inhomogeneity embedded inside a finite circular matrix (which implies the matrix is also at nanoscale) is investigated. The stress boundary conditions are given at the inhomogeneity-matrix interface and the outer boundary of the matrix by the G-M model. The analytic solution for the stress field is finally obtained through the complex variable method. The results show that the stress field inside the inhomogeneity is still uniform (size-dependent) when the surface/interface effect is considered. In addition, the stress field inside the bulk (including the inhomogeneity and the matrix) can be influenced not only by the size and elastic constant of the inhomogeneity, but also by those of the matrix.展开更多
Fast charging capability of lithium-ion batteries is in urgent need for widespread economic success of electric vehicles. However, the application of the fast charging technology often leads to the inevitable lithium ...Fast charging capability of lithium-ion batteries is in urgent need for widespread economic success of electric vehicles. However, the application of the fast charging technology often leads to the inevitable lithium plating on the graphite anode, which is one of the main culprits that endanger battery safety and shorten battery lifespan. The in-depth understanding of the initiation of lithium metal nucleation and the following plating behavior is a key to the development of fast charging cells. Herein, we investigate the overlooked effect of the non-uniform distribution of electrolyte on lithium plating during fast charging. Prior lithium plating occurs on the saturated lithium-graphite compounds in the anode region with sufficient electrolyte since the lithium-ion transport is blocked in the anode region lacking electrolyte. The uniform distribution of electrolyte is crucial for the construction of safe lithium-ion batteries especially in fast charging scenarios.展开更多
A research method and parameter C_v which depicts the spatial inhomogeneity of earthquakeprecursory group, are developed in the paper. The influences of factors, such asinhomogeneous distribution of precursory observa...A research method and parameter C_v which depicts the spatial inhomogeneity of earthquakeprecursory group, are developed in the paper. The influences of factors, such asinhomogeneous distribution of precursory observatory stations, the variety of observing itemnumber at each observatory station and the anomaly number of the same observing item atdifferent stations, etc., which cause the non-earthquake induced inhomogeneity, can beeliminated from C_v. The criteria of C_v to recognize particular spatial pattern of earthquakeprecursory group are also introduced. Based on the method, the spatial inhomogeneity ofradon precursory group and its relation to moderately strong earthquakes occurred in NorthChina during the same period are analyzed. The results show 5 strengthen processes of spatialinhomogeneity of radon precursory group before each of 5 earthquakes with M≥5. 0 in theregion during the period from Jan. 1, 1995 to Feb. 1, 1998. Among them 4 earthquakesoccurred within the time interval which the展开更多
The effect of inhomogeneity of particles on the band-gap of silica colloidal crystals(SCCs) fabricated by vertical deposition method was studied.The optical properties of the crystals were examined.The SEM images and ...The effect of inhomogeneity of particles on the band-gap of silica colloidal crystals(SCCs) fabricated by vertical deposition method was studied.The optical properties of the crystals were examined.The SEM images and transmission spectrum of the crystals showed that the inhomogeneity of particles not only affected the ordering,but also their mid-gap position.When the volume ratio of S particles(VS) to L particles(VL) in suspension was 1:1,the band-gap of silica colloidal crystals changed with the growth of particles.When the ratio was 2:1,the quality of SCCs on substrate was obviously improved simultaneously with the number decreasing of L particles.Especially,the quality of SCCs at the bottom of substrate was the best and its mid-gap(634 nm) was very close to that of theoretic value of S particles(636 nm).When the ratio was 3:1,the effect of L particles became smaller with the number decreasing of L particles in suspension.The mid-gap position(638 nm) of whole SCCs on substrate were all close to that of theoretic value of S particles(636 nm).展开更多
The complex potentials method is used to develop a solution for a screw dislocation interacting with an elliptical piezoelectric inhomogeneity in piezoelectric materials under remote non-uniform antiplane shear and no...The complex potentials method is used to develop a solution for a screw dislocation interacting with an elliptical piezoelectric inhomogeneity in piezoelectric materials under remote non-uniform antiplane shear and non-uniform inplane electric field. The theoretical analysis result is formulated via the conformal mapping and Laurent series expansion in the transformed plane by using complex variable method. The general expression of the complex variables is dirived explicitly in both the elliptical inhomogeneity and the surrounding展开更多
This paper deals with the electro-elastic coupling interaction between a piezoelectric screw dislocation which is located inside the elliptical inhomogeneity and an electrically conductive confocal rigid line under re...This paper deals with the electro-elastic coupling interaction between a piezoelectric screw dislocation which is located inside the elliptical inhomogeneity and an electrically conductive confocal rigid line under remote anti-plane shear stresses and in-plane electrical loads in piezoelectric composite material. The analytical-functions of the complex potentials, stress fields and the image force acting on the piezoelectric screw dislocation are obtained based on the principle of conformal mapping, the method of series expansion, the technical of analytic continuation and the analysis of singularity of complex potentials. The rigid line and the piezoelectric material property combinations upon the image force and the equilibrium position of the dislocation are discussed in detail by the numerical computation.展开更多
The object of the present paper is to study the transient magneto-thermo-visco-elastic stresses in a non-ho- mogeneous anisotropic solid under initial stress. The system of fundamental equations is solved by means of ...The object of the present paper is to study the transient magneto-thermo-visco-elastic stresses in a non-ho- mogeneous anisotropic solid under initial stress. The system of fundamental equations is solved by means of a dual reciprocity boundary element method (DRBEM). In the case of plane deformation, a numerical scheme for the implementation of the method is presented and the numerical computations are presented graphically to show the effects of initial stress and inhomogeneity on the displacement components and thermal stress components.展开更多
Individualized models of respiratory mechanics help to reduce potential harmful effects of mechanical ventilation by supporting the evaluation of patient-specific lung protective ventilation strategies. Assessing vent...Individualized models of respiratory mechanics help to reduce potential harmful effects of mechanical ventilation by supporting the evaluation of patient-specific lung protective ventilation strategies. Assessing ventilation inhomogeneities might be an important aspect in optimizing ventilator settings. The aim of this studyis to capture and analyze ventilation inhomogeneity by a mathematical model using clinical data. The results show that the lung physiology of mechanically ventilated patients without lung condition can be described by an inhomogeneity model revealing two alveolar compartments with median time constants of 0.4 and 3.9 s. Thus, the IHM in combination with specific ventilation maneuver might be suitable to capture lung physiology for model-based optimization of ventilator settings but requires additional image-based investigations to further support the validity of the model.展开更多
An effective method is developed and used to investigate the an-tiplane problem of a rigid line in a confocal elliptic inhomogeneity embedded in aninfinite medium.The analytical solution is obtained. The proposed meth...An effective method is developed and used to investigate the an-tiplane problem of a rigid line in a confocal elliptic inhomogeneity embedded in aninfinite medium.The analytical solution is obtained. The proposed method is basedupon the use of conformal mapping and the theorem of analytic continuation.Specialsolutions which are verified by comparison with existing ones are provided.Finally,the characteristics of stress singularity at the tip of the rigid line inhomogeneity areanalyzed and the extension forces for the crack and the rigid line inhomogeneity arederived.展开更多
Grain boundary(GB)fracture is arguably one of the most important reasons for the catastrophic failure of ductile polycrystalline materials.It is of interest to explore the role of chemical distribution on GB defor-mat...Grain boundary(GB)fracture is arguably one of the most important reasons for the catastrophic failure of ductile polycrystalline materials.It is of interest to explore the role of chemical distribution on GB defor-mation and fracture,as GB segregation becomes a key strategy for tailoring GB properties.Here we report that the inhomogeneous chemical distribution effectively inhibits GB fracture in a model CoCrNi medium entropy alloy compared to a so-called‘average-atom’sample.Atomic deformation kinematics combined with electronic behavior analysis reveals that the strong charge redistribution ability in chemical disor-dered CrCoNi GBs enhances shear deformation and thus prevents GB crack formation and propagation.Inspects on the GBs with different chemical components and chemical distributions suggest that not only disordered chemical distribution but also sufficient“harmonic elements”with large electronic flexibility contribute to improving the GB fracture resistance.This study provides new insight into the influence mechanism of GB chemistry on fracture behavior,and yields a systematic strategy and criterion,from the atoms and electrons level,forward in the design of high-performance materials with enhanced GB fracture resistance.展开更多
The coexistence of superconductivity and charge inhomogeneity was observed in many cuprate superconductors.The relationship between those two is still controversial.Similarly,in the graphene sheets of the intercalated...The coexistence of superconductivity and charge inhomogeneity was observed in many cuprate superconductors.The relationship between those two is still controversial.Similarly,in the graphene sheets of the intercalated graphitic superconductor CaC_(6),the charge inhomogeneity was also observed.We simulate such a system by constructing the Hubbard model on the honeycomb lattice with charge inhomogeneity imposed by force.Utilizing the finite-temperature determinant quantum Monte Carlo algorithm,we examine the relationship between the superconducting pairing and the charge inhomogeneity.An optimal charge inhomogeneity for the d+id-wave pairing is found.While for other artificial charge inhomogeneities,the d+id-wave pairing is monotonically suppressed.The possibleπ-phase shift induced by charge inhomogeneity is also examined.展开更多
In the processing of conventional marine seismic data,seawater is often assumed to have a constant velocity model.However,due to static pressure,temperature difference and other factors,random disturbances may often f...In the processing of conventional marine seismic data,seawater is often assumed to have a constant velocity model.However,due to static pressure,temperature difference and other factors,random disturbances may often frequently in seawater bodies.The impact of such disturbances on data processing results is a topic of theoretical research.Since seawater sound velocity is a difficult physical quantity to measure,there is a need for a method that can generate models conforming to seawater characteristics.This article will combine the Munk model and Perlin noise to propose a two-dimensional dynamic seawater sound velocity model generation method,a method that can generate a dynamic,continuous,random seawater sound velocity model with some regularity at large scales.Moreover,the paper discusses the influence of the inhomogeneity characteristics of seawater on wave field propagation and imaging.The results show that the seawater sound velocity model with random disturbance will have a significant influence on the wave field simulation and imaging results.展开更多
Some achievements on the inhomogeneity test of climatological data series and some correlative conclusions were described,from which we concluded that it was very necessary to test the homogeneity of the Chinese clima...Some achievements on the inhomogeneity test of climatological data series and some correlative conclusions were described,from which we concluded that it was very necessary to test the homogeneity of the Chinese climatological data series.Many techniques on this field developed by foreign experts are suitable for Chinese climatological series,and the main factors for the inhomogeneity of the Chinese climatological data are the relocation of stations and the change of instruments.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.42230608)the UK-China Research&Innovation Partnership Fund through the Met Office Climate Science for Service Partnership(CSSP)China as part of the Newton Fund.
文摘This paper provides a systematic evaluation of the ability of 12 Earth System Models(ESMs)participating in the Coupled Model Intercomparison Project Phase 6(CMIP6)to simulate the spatial inhomogeneity of the atmospheric carbon dioxide(CO_(2))concentration.The multi-model ensemble mean(MME)can reasonably simulate the increasing trend of CO_(2) concentration from 1850 to 2014,compared with the observation data from the Scripps CO_(2) Program and CMIP6 prescribed data,and improves upon the CMIP5 MME CO_(2) concentration(which is overestimated after 1950).The growth rate of CO_(2) concentration in the northern hemisphere(NH)is higher than that in the southern hemisphere(SH),with the highest growth rate in the mid-latitudes of the NH.The MME can also reasonably simulate the seasonal amplitude of CO_(2) concentration,which is larger in the NH than in the SH and grows in amplitude after the 1950s(especially in the NH).Although the results of the MME are reasonable,there is a large spread among ESMs,and the difference between the ESMs increases with time.The MME results show that regions with relatively large CO_(2) concentrations(such as northern Russia,eastern China,Southeast Asia,the eastern United States,northern South America,and southern Africa)have greater seasonal variability and also exhibit a larger inter-model spread.Compared with CMIP5,the CMIP6 MME simulates an average spatial distribution of CO_(2) concentration that is much closer to the site observations,but the CMIP6-inter-model spread is larger.The inter-model differences of the annual means and seasonal cycles of atmospheric CO_(2) concentration are both attributed to the differences in natural sources and sinks of CO_(2) between the simulations.
基金This work is financially supported by Basic Scientific Project of Liaoning Provincial Department of Education(LJKMZ20220591)Science and Technology Plan Project of Changzhou,China(CQ20220057).
文摘The horizontal continuous casting process,the initial step in TP2 copper tubular processing,directly determines the microstructure and properties of copper tubular.However,the process parameters of the continuous casting characterize time variation,multiple disturbances and strong coupling.As a consequence,their influence on a casting billet is difficult to be determined.Due to the above issues,the common factor and special factor analysis of the factor analysis model were used in this study,and the casting experiment and billet metallographic experiment were carried out to diagnose and analyze the reason of the microstructure inhomogeneity.The multiple process parameters were studied and classified using common factor analysis,2 the cast billets with abnormal microstructures were identified by GT^(2) statistics,and the most important factors affecting the microstructural homogeneity were found by special factor analysis.The calculated and experimental results show that the principal parameters influencing the inhomogeneity of solidified microstructure are the primary inlet water pressure and the primary outlet water temperature.According to the consequence of the above investigation,the inhomogeneity of the copper billet microstructure can be effectively improved when the process parameters are controlled and adjusted.
基金the financial support from the National Natural Science Foundation of China (51875317,52222510)Key Research and Development Program of Shandong Province (2021ZLGX01)。
文摘The tensile tests of the extruded ZK60 Mg containing a longitudinal weld seam were carried out at room and elevated temperatures, and the effects of induced microstructure inhomogeneity on tensile deformation behavior was clarified. The results show that the deformation mode, dynamic recrystallization(DRX), texture evolution and mechanical properties are strongly affected by the longitudinal weld seam,temperature, and loading direction. The room temperature(RT) deformation of welding zone is controlled by the dislocation slips with the association of some twins, while twinning plays significant roles in the accommodation of c-axis strain of the coarse grains on matrix zone.The deformation at RT stretched along extrusion direction(ED) and transverse direction(TD) are controlled by basal slip/twinning and basal slip/prismatic slip/twinning, respectively. During high temperature tension, the dislocation cross slip of pyramidal slip is activated, and grain boundary sliding occurred in welding zone, leading to the superplastic behavior. With the increase of tensile temperature, the predominant DRX mode is transformed from continuous DRX to discontinuous DRX. Moreover, the basal poles of the grains spread from TD towards ED with the decrease of maximum pole intensity when stretched along ED, while non-basal textures are transformed to (10-10) fiber texture when stretched along TD. The slip-dominated flow is seen during RT tension along ED, while twinning becomes predominant during RT tension along TD. The fine grain structure causes the superior RT tensile properties along ED of welding zone with ultimate tensile strength of 315 MPa and elongation to failure of 13.8%. With the increase of tensile temperature, the slipping-dominated deformation is transformed into twinning-dominated, causing the decrease of strength and increase of elongation.
基金Project supported by the National Natural Science Foundation of China(No.11272121)the Natural Sciences and Engineering Research Council of Canada(No.RGPIN-2017-03716115112).
文摘We prove that the interior stresses within both a non-parabolic open inhomogeneity and another interacting non-elliptical closed inhomogeneity can still remain constant when the matrix is simultaneously under the action of a screw dislocation and uniform remote anti-plane stresses.The constancy of interior stresses is realized through the construction of a conformal mapping function for the doubly connected domain occupied by the surrounding matrix.The mapping function is endowed with the information describing the screw dislocation via the incorporation of two specifically defined logarithmic terms.The constant interior stress fields are observed to be independent of the specific open and closed shapes of the two inhomogeneities and the existence of the screw dislocation.In contrast,the existence of the neighboring screw dislocation significantly affects the open and closed shapes of the two inhomogeneities.
基金Project(10472030) supported by the National Natural Science Foundation of China
文摘A theoretical model was suggested which describes the generation of the misfit dislocation dipole in the system of the viscoelastic matrix containing a circular stiff nanoscale inhomogeneity.The critical condition of misfit dislocation dipole and the solution of equilibrium position were given.The influence of the ratio of shear modulus,the misfit strain and viscosity on the equilibrium of the dislocation and critical parameter of inhomogeneity was investigated.The result shows that the equilibrium position de increases with the increase of the ratio of original shear modulus and the effect decreases with the increase of viscosity of matrix.Along with the increase of viscosity of matrix,de first increases and then decreases and possesses maximum value when t=0.3τ and tends to a stable value when t≥1.0τ.Along with the increase of viscosity of matrix,Rc first decreases and then increases and possesses minimum value when t=0.3τ and tends to a stable value when t≥1.0τ.
文摘Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.
基金support of the China Scholarship Councilthe support of the National Natural Science Foundation of China (11472130)the Natural Sciences and Engineering Research Council of Canada for the financial support
文摘The Gurtin-Murdoch model has found wide applications in analyzing the mechanical behaviors of nanocomposites with surface/interface effect. In the existing literature, the matrix is usually assumed to be infinite and the surface/interface effect is considered only at the inhomogeneity-matrix interface. This assumption is indeed valid as the matrix is usually at macroscale rather than nanoscale. However, if the size of the matrix decreases to the nanoscale too, the surface/interface effect will have to be considered at the outer boundary of the matrix. In this paper, the plane deformation of a circular nano-inhomogeneity embedded inside a finite circular matrix (which implies the matrix is also at nanoscale) is investigated. The stress boundary conditions are given at the inhomogeneity-matrix interface and the outer boundary of the matrix by the G-M model. The analytic solution for the stress field is finally obtained through the complex variable method. The results show that the stress field inside the inhomogeneity is still uniform (size-dependent) when the surface/interface effect is considered. In addition, the stress field inside the bulk (including the inhomogeneity and the matrix) can be influenced not only by the size and elastic constant of the inhomogeneity, but also by those of the matrix.
基金supported by the Beijing Natural Science Foundation (JQ20004)the National Key Research and Development Program (2021YFB2400300)+1 种基金the National Natural Science Foundation of China (22109083)the Scientific and Technological Key Project of Shanxi Province (20191102003)。
文摘Fast charging capability of lithium-ion batteries is in urgent need for widespread economic success of electric vehicles. However, the application of the fast charging technology often leads to the inevitable lithium plating on the graphite anode, which is one of the main culprits that endanger battery safety and shorten battery lifespan. The in-depth understanding of the initiation of lithium metal nucleation and the following plating behavior is a key to the development of fast charging cells. Herein, we investigate the overlooked effect of the non-uniform distribution of electrolyte on lithium plating during fast charging. Prior lithium plating occurs on the saturated lithium-graphite compounds in the anode region with sufficient electrolyte since the lithium-ion transport is blocked in the anode region lacking electrolyte. The uniform distribution of electrolyte is crucial for the construction of safe lithium-ion batteries especially in fast charging scenarios.
基金This was a key program(9507435)sponsored by the Joint Earthquake Science Foundation of China under the 9th Five-year Plan.
文摘A research method and parameter C_v which depicts the spatial inhomogeneity of earthquakeprecursory group, are developed in the paper. The influences of factors, such asinhomogeneous distribution of precursory observatory stations, the variety of observing itemnumber at each observatory station and the anomaly number of the same observing item atdifferent stations, etc., which cause the non-earthquake induced inhomogeneity, can beeliminated from C_v. The criteria of C_v to recognize particular spatial pattern of earthquakeprecursory group are also introduced. Based on the method, the spatial inhomogeneity ofradon precursory group and its relation to moderately strong earthquakes occurred in NorthChina during the same period are analyzed. The results show 5 strengthen processes of spatialinhomogeneity of radon precursory group before each of 5 earthquakes with M≥5. 0 in theregion during the period from Jan. 1, 1995 to Feb. 1, 1998. Among them 4 earthquakesoccurred within the time interval which the
基金Supported by National Key Basic Research Special Fund (No. 2006CB932606)National Natural Science Foundation of China (No. 50702077)
文摘The effect of inhomogeneity of particles on the band-gap of silica colloidal crystals(SCCs) fabricated by vertical deposition method was studied.The optical properties of the crystals were examined.The SEM images and transmission spectrum of the crystals showed that the inhomogeneity of particles not only affected the ordering,but also their mid-gap position.When the volume ratio of S particles(VS) to L particles(VL) in suspension was 1:1,the band-gap of silica colloidal crystals changed with the growth of particles.When the ratio was 2:1,the quality of SCCs on substrate was obviously improved simultaneously with the number decreasing of L particles.Especially,the quality of SCCs at the bottom of substrate was the best and its mid-gap(634 nm) was very close to that of theoretic value of S particles(636 nm).When the ratio was 3:1,the effect of L particles became smaller with the number decreasing of L particles in suspension.The mid-gap position(638 nm) of whole SCCs on substrate were all close to that of theoretic value of S particles(636 nm).
文摘The complex potentials method is used to develop a solution for a screw dislocation interacting with an elliptical piezoelectric inhomogeneity in piezoelectric materials under remote non-uniform antiplane shear and non-uniform inplane electric field. The theoretical analysis result is formulated via the conformal mapping and Laurent series expansion in the transformed plane by using complex variable method. The general expression of the complex variables is dirived explicitly in both the elliptical inhomogeneity and the surrounding
基金supported by the Science Fund of State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body (60870005)the National Natural Science Foundation of China (10872065)
文摘This paper deals with the electro-elastic coupling interaction between a piezoelectric screw dislocation which is located inside the elliptical inhomogeneity and an electrically conductive confocal rigid line under remote anti-plane shear stresses and in-plane electrical loads in piezoelectric composite material. The analytical-functions of the complex potentials, stress fields and the image force acting on the piezoelectric screw dislocation are obtained based on the principle of conformal mapping, the method of series expansion, the technical of analytic continuation and the analysis of singularity of complex potentials. The rigid line and the piezoelectric material property combinations upon the image force and the equilibrium position of the dislocation are discussed in detail by the numerical computation.
文摘The object of the present paper is to study the transient magneto-thermo-visco-elastic stresses in a non-ho- mogeneous anisotropic solid under initial stress. The system of fundamental equations is solved by means of a dual reciprocity boundary element method (DRBEM). In the case of plane deformation, a numerical scheme for the implementation of the method is presented and the numerical computations are presented graphically to show the effects of initial stress and inhomogeneity on the displacement components and thermal stress components.
基金The German Federal Ministry of Education and Research (WiM-Vent, Grants01IB10002D, PulMODS Grant 01DR12095) EU FP7 PIRSES--GA-2012-318943 eTime
文摘Individualized models of respiratory mechanics help to reduce potential harmful effects of mechanical ventilation by supporting the evaluation of patient-specific lung protective ventilation strategies. Assessing ventilation inhomogeneities might be an important aspect in optimizing ventilator settings. The aim of this studyis to capture and analyze ventilation inhomogeneity by a mathematical model using clinical data. The results show that the lung physiology of mechanically ventilated patients without lung condition can be described by an inhomogeneity model revealing two alveolar compartments with median time constants of 0.4 and 3.9 s. Thus, the IHM in combination with specific ventilation maneuver might be suitable to capture lung physiology for model-based optimization of ventilator settings but requires additional image-based investigations to further support the validity of the model.
基金The project supported by the National Natural Science Foundation of Chinathe State Education Commission Foundation and the Failure Mechanics Lab of SEdC
文摘An effective method is developed and used to investigate the an-tiplane problem of a rigid line in a confocal elliptic inhomogeneity embedded in aninfinite medium.The analytical solution is obtained. The proposed method is basedupon the use of conformal mapping and the theorem of analytic continuation.Specialsolutions which are verified by comparison with existing ones are provided.Finally,the characteristics of stress singularity at the tip of the rigid line inhomogeneity areanalyzed and the extension forces for the crack and the rigid line inhomogeneity arederived.
基金supported by the National Natural Science Foundation of China (NSFC) (Nos.12102433,U2241285,11972346 and U2141204)the NSFC BasicScience CenterProgram for"Multi-scale Problems in Nonlinear Mechanics" (No.11988102)the Key Research Program of the Chinese Academy of Sciences (No.ZDRW-CN-2021-2-3).
文摘Grain boundary(GB)fracture is arguably one of the most important reasons for the catastrophic failure of ductile polycrystalline materials.It is of interest to explore the role of chemical distribution on GB defor-mation and fracture,as GB segregation becomes a key strategy for tailoring GB properties.Here we report that the inhomogeneous chemical distribution effectively inhibits GB fracture in a model CoCrNi medium entropy alloy compared to a so-called‘average-atom’sample.Atomic deformation kinematics combined with electronic behavior analysis reveals that the strong charge redistribution ability in chemical disor-dered CrCoNi GBs enhances shear deformation and thus prevents GB crack formation and propagation.Inspects on the GBs with different chemical components and chemical distributions suggest that not only disordered chemical distribution but also sufficient“harmonic elements”with large electronic flexibility contribute to improving the GB fracture resistance.This study provides new insight into the influence mechanism of GB chemistry on fracture behavior,and yields a systematic strategy and criterion,from the atoms and electrons level,forward in the design of high-performance materials with enhanced GB fracture resistance.
基金sponsored by the Natural Science Foundation of Chongqing,China(Grant No.cstc2021jcyj-msxmX1009)the Joint Guiding Project of Natural Science Foundation of Heilongjiang Province(Grant No.LH2019A011).
文摘The coexistence of superconductivity and charge inhomogeneity was observed in many cuprate superconductors.The relationship between those two is still controversial.Similarly,in the graphene sheets of the intercalated graphitic superconductor CaC_(6),the charge inhomogeneity was also observed.We simulate such a system by constructing the Hubbard model on the honeycomb lattice with charge inhomogeneity imposed by force.Utilizing the finite-temperature determinant quantum Monte Carlo algorithm,we examine the relationship between the superconducting pairing and the charge inhomogeneity.An optimal charge inhomogeneity for the d+id-wave pairing is found.While for other artificial charge inhomogeneities,the d+id-wave pairing is monotonically suppressed.The possibleπ-phase shift induced by charge inhomogeneity is also examined.
基金The General Program of National Natural Science Foundation of China under contract No.42074150。
文摘In the processing of conventional marine seismic data,seawater is often assumed to have a constant velocity model.However,due to static pressure,temperature difference and other factors,random disturbances may often frequently in seawater bodies.The impact of such disturbances on data processing results is a topic of theoretical research.Since seawater sound velocity is a difficult physical quantity to measure,there is a need for a method that can generate models conforming to seawater characteristics.This article will combine the Munk model and Perlin noise to propose a two-dimensional dynamic seawater sound velocity model generation method,a method that can generate a dynamic,continuous,random seawater sound velocity model with some regularity at large scales.Moreover,the paper discusses the influence of the inhomogeneity characteristics of seawater on wave field propagation and imaging.The results show that the seawater sound velocity model with random disturbance will have a significant influence on the wave field simulation and imaging results.
基金supported by the special foundation project of Ministry of Science and Technology of PRC(No.2001DEA 30029-01)
文摘Some achievements on the inhomogeneity test of climatological data series and some correlative conclusions were described,from which we concluded that it was very necessary to test the homogeneity of the Chinese climatological data series.Many techniques on this field developed by foreign experts are suitable for Chinese climatological series,and the main factors for the inhomogeneity of the Chinese climatological data are the relocation of stations and the change of instruments.