Currently,there are a limited number of dynamic models available for braided composite plates with large overall motions,despite the incorporation of three-dimensional(3D)braided composites into rotating blade compone...Currently,there are a limited number of dynamic models available for braided composite plates with large overall motions,despite the incorporation of three-dimensional(3D)braided composites into rotating blade components.In this paper,a dynamic model of 3D 4-directional braided composite thin plates considering braiding directions is established.Based on Kirchhoff's plate assumptions,the displacement variables of the plate are expressed.By incorporating the braiding directions into the constitutive equation of the braided composites,the dynamic model of the plate considering braiding directions is obtained.The effects of the speeds,braiding directions,and braided angles on the responses of the plate with fixed-axis rotation and translational motion,respectively,are investigated.This paper presents a dynamic theory for calculating the deformation of 3D braided composite structures undergoing both translational and rotational motions.It also provides a simulation method for investigating the dynamic behavior of non-isotropic material plates in various applications.展开更多
This study examined the dynamic characteristics of upper airway collapse at soft palate level in patients with obstructive sleep apnea/hypopnea syndrome（OSAHS） by using dynamic 3-Dimensional（3-D） CT imaging.A tota...This study examined the dynamic characteristics of upper airway collapse at soft palate level in patients with obstructive sleep apnea/hypopnea syndrome（OSAHS） by using dynamic 3-Dimensional（3-D） CT imaging.A total of 41 male patients who presented with 2 of the following symptoms,i.e.,daytime sleepiness and fatigue,frequent snoring,and apnea with witness,were diagnosed as having OSAHS.They underwent full-night polysomnography and then dynamic 3-D CT imaging of the upper airway during quiet breathing and in Muller＇s maneuver.The soft palate length（SPL）,the minimal cross-sectional area of the retropalatal region（mXSA-RP）,and the vertical distance from the hard palate to the upper posterior part of the hyoid（hhL） were compared between the two breathing states.These parameters,together with hard palate length（HPL）,were also compared between mild/moderate and severe OSAHS groups.Association of these parameters with the severity of OSAHS [as reflected by apnea hypopnea index（AHI） and the lowest saturation of blood oxygen（LSaO2）] was examined.The results showed that 31 patients had severe OSAHS,and 10 mild/moderate OSAHS.All the patients had airway obstruction at soft palate level.mXSA-RP was significantly decreased and SPL remarkably increased during Muller＇s maneuver as compared with the quiet breathing state.There were no significant differences in these airway parameters（except the position of the hyoid bone） between severe and mild/moderate OSAHS groups.And no significant correlation between these airway parameters and the severity of OSAHS was found.The position of hyoid was lower in the severe OSAHS group than in the mild/moderate OSAHS group.The patients in group with body mass index（BMI）≥26 had higher collapse ratio of mXSA-RP,greater neck circumference and smaller mXSA-RP in the Muller＇s maneuver than those in group with BMI26（P0.05 for all）.It was concluded that dynamic 3-D CT imaging could dynamically show the upper airway changes at soft palate level in OSAHS patients.All the OSAHS patients had airway obstruction of various degrees at soft palate level.But no correlation was observed between the airway change at soft palate level and the severity of OSAHS.The patients in group with BMI≥26 were more likely to develop airway obstruction at soft palate level than those with BMI26.展开更多
Under investigation in this paper is a generalized(3+1)-dimensional Kadomtsev-Petviashvili equation in fluid dynamics and plasma physics.Soliton and one-periodic-wave solutions are obtained via the Hirota bilinear met...Under investigation in this paper is a generalized(3+1)-dimensional Kadomtsev-Petviashvili equation in fluid dynamics and plasma physics.Soliton and one-periodic-wave solutions are obtained via the Hirota bilinear method and Hirota-Riemann method.Magnitude and velocity of the one soliton are derived.Graphs are presented to discuss the solitons and one-periodic waves:the coefficients in the equation can determine the velocity components of the one soliton,but cannot alter the soliton magnitude;the interaction between the two solitons is elastic;the coefficients in the equation can influence the periods and velocities of the periodic waves.Relation between the one-soliton solution and one-periodic wave solution is investigated.展开更多
Focusing on the study of the components of mechanical rotational body,the data structure and algorithm of component model generation are discussed.Some problems in assembly process of 3 dimensional graph of component...Focusing on the study of the components of mechanical rotational body,the data structure and algorithm of component model generation are discussed.Some problems in assembly process of 3 dimensional graph of components are studied in great detail.展开更多
The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its ma...The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its main body is bestraddle in air,and has aerial intersections between its parts. This complex feature made cloverleaf junction quite different from buildings and terrain, therefore, it is difficult to express this kind of spatial objects in the same way as for buildings and terrain. In this paper,authors analyze spatial characteristics of cloverleaf junction, propose an all-constraint points TIN algorithm to partition cloverleaf junction road surface, and develop a method to visualize cloverleaf junction road surface using TIN. In order to manage cloverleaf junction data efficiently, the authors also analyzed the mechanism of 3DCM data management, extended BLOB type in relational database, and combined R-tree index to manage 3D spatial data. Based on this extension, an appropriate data展开更多
Quantum well infrared photodetectors(QWIPs) based on intersubband transitions hold significant potential for high bandwidth operation. In this work, we establish a carrier transport optimization model incorporating el...Quantum well infrared photodetectors(QWIPs) based on intersubband transitions hold significant potential for high bandwidth operation. In this work, we establish a carrier transport optimization model incorporating electron injection at the emitter to investigate the carrier dynamics time and impedance spectroscopy in GaAs/AlGaAs QWIPs. Our findings provide novel evidence that the escape time of electrons is the key limiting factor for the 3-dB bandwidth of QWIPs. Moreover, to characterize the impact of carrier dynamics time and non-equilibrium space charge region on impedance, we developed an equivalent circuit model where depletion region resistance and capacitance are employed to describe non-equilibrium space charge region. Using this model, we discovered that under illumination, both net charge accumulation caused by variations in carrier dynamics times within quantum wells and changes in width of non-equilibrium space charge region exert different dominant influences on depletion region capacitance at various doping concentrations.展开更多
After the hot deformation sample of Ti-10V-2Fe-3Al alloy was treated by solid solution in theα+βtwo-phase region,the coarseβgrains that often appeared in theβsingle phase region were observed in the local region,i...After the hot deformation sample of Ti-10V-2Fe-3Al alloy was treated by solid solution in theα+βtwo-phase region,the coarseβgrains that often appeared in theβsingle phase region were observed in the local region,indicating that the abnormal grain growth occurred in the local microstructural region,and the macrostructure also showed abnormally coarse grains(ACGs).The dynamic recrystallization(DRX)behavior of Ti-10V-2Fe-3Al titanium alloy was systematically investigated through hot compression tests on the Gleeble-3800 system.The DRX model ofβgrains was established,and the quantitative correlation between DRX characteristics and the appearance of ACG was clarified.Based on these results,a numerical simulation platform was developed to realize the visual prediction of ACG distribution.The results show that the increase of deformation temperature and the decrease of strain rate both contribute to a significant increase in the grain size(d_(DRX)))and volume fraction(X_(DRX))of DRXed grains.However,the proper X_(DRX)and smaller d_(DRX))at low deformation temperature and high strain rate make the macro and microstructure show ACGs after solid solution.Interestingly,if the DRX degree is excessive or insufficient,ACGs cannot be produced,indicating that ACGs are solid solution products based on the appropriate DRX degree.According to the flow curves and statistical results of microstructure,the quantitative model of DRX kinetics and DRX grain size model were constructed,and the quantitative criterion model that is related to the formation of ACG with grain size(d_(DRX)))and volume fraction(X_(DRX))of DRXed grains as the key parameters was established,i.e.,d_(DRX)≤2.60µm,72.5%≤X_(DRX)≤87.9%.By integrating the subroutine of coarse grain criterion,the isothermal compression process of cylindrical samples and the actual die forging process of H-shaped parts were simulated by DEFORM-3D software of finite element(FE),respectively,and the visual prediction of the distribution of macroscopic ACGs was realized.There is a good consistency between the tested results and the simulated results,indicating a strong correlation between macroscopic ACGs and microscopic DRX.展开更多
Since programing complex and dynamic heat source model for welding simulation is a complex job,the parametric methods are studied in this paper.Firstly,an overall flow to achieve automatically modeling welding was int...Since programing complex and dynamic heat source model for welding simulation is a complex job,the parametric methods are studied in this paper.Firstly,an overall flow to achieve automatically modeling welding was introduced.Secondly,an expert module rule for selecting welding heat source model was founded,which is based on simulation knowledge and experiences.Thirdly,a modularity routine method was investigated using writing with C++programing,which automatically creates subroutines of 3D dynamic heat source model for user.To realize the dynamic weld path,the local weld path coordinate system was moved in the global coordinate system and it is used to model the direction of weld gun,welding path and welding pose.The weld path data file was prepared by the automatic tool for the welding heat source subroutines.All above functions were integrated in the user interface and the connection with architecture was introduced.At last,a laser beam welding heat source modeling was automatically modeled and the weld pool geometry was compared with the reported literature.It demonstrated that the automated tool is valid for welding simulation.Since modeling became convenient for welding simulation using the tool proposed,it could be easy and useful for welding engineers to acquire the needed information.展开更多
Mucoepidermoid carcinoma undergoes uniquely vigorous angiogenic and neovascularization processes,possibly due to proliferation of vascular endothelial cells(ECs) induced by mucoepidermoid carcinoma cells(MCCs) in thei...Mucoepidermoid carcinoma undergoes uniquely vigorous angiogenic and neovascularization processes,possibly due to proliferation of vascular endothelial cells(ECs) induced by mucoepidermoid carcinoma cells(MCCs) in their three-dimensional(3D) microenvironment.To date,no studies have dealt with tumor cells and vascular ECs from the same origin of mucoepidermoid carcinoma using the in vitro 3D microenvironment model.In this context,the current research aims to observe neovascularization with mucoepidermoid carcinoma microvascular ECs(MCMECs) conditioned by the microenvironment in the 3D collagen matrix model.We observed the growth of MCMECs purified by immunomagnetic beads and induced by MCCs,and characteristics of tubule-like structures(TLSs) formed by induced MCMECs or non-induced MCMECs.The assessment parameters involved the growth curve,the length,the outer and inner diameters,and the wall thickness of the TLSs,and the cell cycle.Results showed that MCCs induced formation of the TLSs in the 3D collagen matrix model.A statistically significant difference was noted regarding the count of TLSs between the control group and the induction group on the 4th day of culture(t=5.00,P=0.001).The outer and inner diameters(t1=5.549,P1=0.000;t2=10.663,P2=0.000) and lengths(t=18.035,P=0.000) of the TLSs in the induction group were statistically significant larger than those in the control group.The TLSs were formed at the earlier time in the induction group compared with the control group.It is concluded that MCCs promote growth and migration of MCMECs,and formation of the TLSs.The 3D collagen matrix model with MCMECs induced by MCCs in the current research may be a favorable choice for research on pro-angiogenic factors in progression of mucoepidermoid carcinoma.展开更多
Lie symmetry analysis is applied to a(3+1)-dimensional Virasoro integrable model and the corresponding similarity reduction equations are obtained with the different infinitesimal generators.Invariant solutions with a...Lie symmetry analysis is applied to a(3+1)-dimensional Virasoro integrable model and the corresponding similarity reduction equations are obtained with the different infinitesimal generators.Invariant solutions with arbitrary functions for the(3+1)-dimensional Virasoro integrable model,including the interaction solution between a kink and a soliton,the lump-type solution and periodic solutions,have been studied analytically and graphically.展开更多
The summer and winter circulations in the South China Sea (SCS) including the surface elevation and water temperature are simulated using the model described by Cai and Li (1996) with the monthly mean wind stress and ...The summer and winter circulations in the South China Sea (SCS) including the surface elevation and water temperature are simulated using the model described by Cai and Li (1996) with the monthly mean wind stress and air temperature field at the 1000 mb level from the European Centre for Medium-Range Weather Forecasts as inputs. The boundary conditions at Bashi Channel and Taiwan Strait are taken from the simulation results of the Kuroshio using the same numerical model with a grid size of 0.5°×0.5° and the results of Cai and Li (1996) as boundary conditions. The computational domain for the present paper is between 100°E and 123°E and between 4.5°N and 27°N. The horizontal resolution is 0.25°×0.25° and the vertical variations of the velocity components are resolved by 6 layers The computed steady flow, temperature and elevation fields are consistent with the corresponding fields observed. In particular, the temperature and elevation fields of the South China Sea Warm Current (SCSWC) have been successfully simulated. The paths of the branch of the Kuroshio entering the South China Sea (SCSBK) through Bashi Channel in winter and summer are discussed It is found that the SCSBK flows southward to the southern SCS from the coast of the Guangdong Province. A portion of the SCSBK returns to the Bashi Channel and subdivides again in deep waters in winter with a branch flows to the south along the coast of the Philippines instead of flowing back to the Pacific In addition, our results confirm the existence of a eastward current to the northeast of Dongsha in summer with the Kuroshio as its source as suggested by Huang et al. Since the value of the eddy viscosity adopted for the simulation of the Kuroshio is on the high side, resulting in a weaker west boundary current in the western Pacific as the boundary conditions for the present simulations, some deviations from the actual situations are expected although the results are in general consistent with observations.展开更多
We obtain exact spatiotemporal similaritons to a （3＋ l）-dimensional inhomogeneous nonlinear Schrodinger equation, which describes the propagation of optical pulses in a cubic-quintic nonlinearity medium with distri...We obtain exact spatiotemporal similaritons to a （3＋ l）-dimensional inhomogeneous nonlinear Schrodinger equation, which describes the propagation of optical pulses in a cubic-quintic nonlinearity medium with distributed dispersion and gain. A one-to-one correspondence between such self-similar waves and solutions of the elliptic equation is found when a certain compatibility condition is satisfied. Based on exact solutions, we discuss evolutional behaviors of self-similar cnoidal waves and chirped similaritons in two kind of typicai soliton control systems. Moreover, the comparison between chirped similaritons and chirp-free solitons is given.展开更多
Hot deformation behaviors and microstructure evolution of Ti-3Al-5Mo-4Cr-2Zr-1Fe(Ti-35421)alloy in theβsingle field are investigated by isothermal compression tests on a Gleeble-3500 simulator at temperatures of 820-...Hot deformation behaviors and microstructure evolution of Ti-3Al-5Mo-4Cr-2Zr-1Fe(Ti-35421)alloy in theβsingle field are investigated by isothermal compression tests on a Gleeble-3500 simulator at temperatures of 820-900°C and strain rates of 0.001-1 s^(-1).The research results show that discontinuous yield phenomenon and rheological softening are affected by the strain rates and deformation temperatures.The critical conditions for dynamic recrystallization and kinetic model of Ti-35421 alloy are determined,and the Arrhenius constitutive model is constructed.The rheological behaviors of Ti-35421 alloys aboveβphase transformation temperature are predicted by the constitutive model accurately.The EBSD analysis proves that the deformation softening is controlled by dynamic recovery and dynamic recrystallization.In addition,continuous dynamic recrystallization is determined during hot deformation,and the calculation model for recrystallization grain sizes is established.Good linear dependency between the experimental and simulated values of recrystallized grain sizes indicates that the present model can be used for the prediction of recrystallized grain size with high accuracy.展开更多
Rockslides are one of the most common geological hazards in mountainous areas and can pose significant threats to the safety of human lives and infrastructures. Studying the dynamic fragmentation process, and fragment...Rockslides are one of the most common geological hazards in mountainous areas and can pose significant threats to the safety of human lives and infrastructures. Studying the dynamic fragmentation process, and fragment characteristics of rock blocks during rockslides is of great significance. In this study,the influences of the slope angle on the dynamic fragmentation process, damage and energy evolution,and the fragments’ flying velocity and flying angle were systematically investigated using a coupled 3D FEM-DEM method. An improved fragment search algorithm was first proposed to more effectively extract the information of the fragments after impacting. The input parameters in the numerical modeling were carefully calibrated based on the quasi-static uniaxial compression tests and the rockimpact tests. The complex fragmentation process of rock block sliding along an inclined slope was simulated. The results indicate that the fragmentation intensity gradually increases with increasing the slope angle, and the fragmentation intensity of the front region of the rock block is always higher than that of the rear region. Additionally, the slope angle can significantly affect the damage ratio, energy dissipation, and the ratio of tensile crack to shear crack during the rockslides. The number of the fragments having higher flying velocities and larger flying angles increases with increasing the slope angle,which contributes to a larger spreading distance and a wider deposition area.展开更多
Based on computer graphics principle, technology and 3D graphics software, this paper deals with the 3D part design, assembly and animation of shearer in longwall integrated mechanized coal mining. The matixes of kine...Based on computer graphics principle, technology and 3D graphics software, this paper deals with the 3D part design, assembly and animation of shearer in longwall integrated mechanized coal mining. The matixes of kinetic and geometry relationships and 3 dimension space coordinate systems are built for the cut drums, arms and shearer body. The methods of 3D modeling, dynamic simulation and relative technique problems are discussed.展开更多
The dynamic phase transition properties for ferroelectric nanotube under a spin-1/2 transverse Ising model are studied under the effective field theory(EFT)with correlations.The temperature effects on the pseudo-spin ...The dynamic phase transition properties for ferroelectric nanotube under a spin-1/2 transverse Ising model are studied under the effective field theory(EFT)with correlations.The temperature effects on the pseudo-spin systems are unveiled in three-dimensional(3-D)and two-dimensional(2-D)phase diagrams.Moreover,the dynamic behaviors of exchange interactions on the 3-D and 2-D phase transitions under high temperature are exhibited.The results present that it is hard to obtain pure ferroelectric phase under high temperature;that is,the vibration of orderly pseudo-spins cannot be eliminated completely.展开更多
In this paper,we give the general interaction solution to the(3+1)-dimensional Jimbo–Miwa equation.The general interaction solution contains the classical interaction solution.As an example,by using the generalized b...In this paper,we give the general interaction solution to the(3+1)-dimensional Jimbo–Miwa equation.The general interaction solution contains the classical interaction solution.As an example,by using the generalized bilinear method and symbolic computation by using Maple software,novel interaction solutions under certain constraints of the(3+1)-dimensional Jimbo–Miwa equation are obtained.Via three-dimensional plots,contour plots and density plots with the help of Maple,the physical characteristics and structures of these waves are described very well.These solutions greatly enrich the exact solutions to the(3+1)-dimensional Jimbo–Miwa equation found in the existing literature.展开更多
We construct analytical self-similar solutions for the generalized (3+1)-dimensional nonlinear Schrdinger equation with polynomial nonlinearity of arbitrary order. As an example, we list self-similar solutions of quin...We construct analytical self-similar solutions for the generalized (3+1)-dimensional nonlinear Schrdinger equation with polynomial nonlinearity of arbitrary order. As an example, we list self-similar solutions of quintic nonlinear Schrdinger equation with distributed dispersion and distributed linear gain, including bright similariton solution, fractional and combined Jacobian elliptic function solutions. Moreover, we discuss self-similar evolutional dynamic behaviors of these solutions in the dispersion decreasing fiber and the periodic distributed amplification system.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.12372071 and 12372070)the Aeronautical Science Fund of China(No.2022Z055052001)the Foundation of China Scholarship Council(No.202306830079)。
文摘Currently,there are a limited number of dynamic models available for braided composite plates with large overall motions,despite the incorporation of three-dimensional(3D)braided composites into rotating blade components.In this paper,a dynamic model of 3D 4-directional braided composite thin plates considering braiding directions is established.Based on Kirchhoff's plate assumptions,the displacement variables of the plate are expressed.By incorporating the braiding directions into the constitutive equation of the braided composites,the dynamic model of the plate considering braiding directions is obtained.The effects of the speeds,braiding directions,and braided angles on the responses of the plate with fixed-axis rotation and translational motion,respectively,are investigated.This paper presents a dynamic theory for calculating the deformation of 3D braided composite structures undergoing both translational and rotational motions.It also provides a simulation method for investigating the dynamic behavior of non-isotropic material plates in various applications.
文摘This study examined the dynamic characteristics of upper airway collapse at soft palate level in patients with obstructive sleep apnea/hypopnea syndrome（OSAHS） by using dynamic 3-Dimensional（3-D） CT imaging.A total of 41 male patients who presented with 2 of the following symptoms,i.e.,daytime sleepiness and fatigue,frequent snoring,and apnea with witness,were diagnosed as having OSAHS.They underwent full-night polysomnography and then dynamic 3-D CT imaging of the upper airway during quiet breathing and in Muller＇s maneuver.The soft palate length（SPL）,the minimal cross-sectional area of the retropalatal region（mXSA-RP）,and the vertical distance from the hard palate to the upper posterior part of the hyoid（hhL） were compared between the two breathing states.These parameters,together with hard palate length（HPL）,were also compared between mild/moderate and severe OSAHS groups.Association of these parameters with the severity of OSAHS [as reflected by apnea hypopnea index（AHI） and the lowest saturation of blood oxygen（LSaO2）] was examined.The results showed that 31 patients had severe OSAHS,and 10 mild/moderate OSAHS.All the patients had airway obstruction at soft palate level.mXSA-RP was significantly decreased and SPL remarkably increased during Muller＇s maneuver as compared with the quiet breathing state.There were no significant differences in these airway parameters（except the position of the hyoid bone） between severe and mild/moderate OSAHS groups.And no significant correlation between these airway parameters and the severity of OSAHS was found.The position of hyoid was lower in the severe OSAHS group than in the mild/moderate OSAHS group.The patients in group with body mass index（BMI）≥26 had higher collapse ratio of mXSA-RP,greater neck circumference and smaller mXSA-RP in the Muller＇s maneuver than those in group with BMI26（P0.05 for all）.It was concluded that dynamic 3-D CT imaging could dynamically show the upper airway changes at soft palate level in OSAHS patients.All the OSAHS patients had airway obstruction of various degrees at soft palate level.But no correlation was observed between the airway change at soft palate level and the severity of OSAHS.The patients in group with BMI≥26 were more likely to develop airway obstruction at soft palate level than those with BMI26.
基金supported by the National Natural Science Foundation of China under Grant No.11272023by the Fundamental Research Funds for the Central Universities under Grant No.50100002016105010。
文摘Under investigation in this paper is a generalized(3+1)-dimensional Kadomtsev-Petviashvili equation in fluid dynamics and plasma physics.Soliton and one-periodic-wave solutions are obtained via the Hirota bilinear method and Hirota-Riemann method.Magnitude and velocity of the one soliton are derived.Graphs are presented to discuss the solitons and one-periodic waves:the coefficients in the equation can determine the velocity components of the one soliton,but cannot alter the soliton magnitude;the interaction between the two solitons is elastic;the coefficients in the equation can influence the periods and velocities of the periodic waves.Relation between the one-soliton solution and one-periodic wave solution is investigated.
文摘Focusing on the study of the components of mechanical rotational body,the data structure and algorithm of component model generation are discussed.Some problems in assembly process of 3 dimensional graph of components are studied in great detail.
文摘The research work has been seldom done about cloverleaf junction expression in a 3-dimensional city model (3DCM). The main reason is that the cloverleaf junction is often in a complex and enormous construction. Its main body is bestraddle in air,and has aerial intersections between its parts. This complex feature made cloverleaf junction quite different from buildings and terrain, therefore, it is difficult to express this kind of spatial objects in the same way as for buildings and terrain. In this paper,authors analyze spatial characteristics of cloverleaf junction, propose an all-constraint points TIN algorithm to partition cloverleaf junction road surface, and develop a method to visualize cloverleaf junction road surface using TIN. In order to manage cloverleaf junction data efficiently, the authors also analyzed the mechanism of 3DCM data management, extended BLOB type in relational database, and combined R-tree index to manage 3D spatial data. Based on this extension, an appropriate data
基金financially supported by the National Natural Science Foundation of China (Grant No. 61991442)。
文摘Quantum well infrared photodetectors(QWIPs) based on intersubband transitions hold significant potential for high bandwidth operation. In this work, we establish a carrier transport optimization model incorporating electron injection at the emitter to investigate the carrier dynamics time and impedance spectroscopy in GaAs/AlGaAs QWIPs. Our findings provide novel evidence that the escape time of electrons is the key limiting factor for the 3-dB bandwidth of QWIPs. Moreover, to characterize the impact of carrier dynamics time and non-equilibrium space charge region on impedance, we developed an equivalent circuit model where depletion region resistance and capacitance are employed to describe non-equilibrium space charge region. Using this model, we discovered that under illumination, both net charge accumulation caused by variations in carrier dynamics times within quantum wells and changes in width of non-equilibrium space charge region exert different dominant influences on depletion region capacitance at various doping concentrations.
基金Projects(52275388,52075474)supported by the National Natural Science Foundation of ChinaProject(236Z1008G)supported by the Special Project of Hebei Provincial Central Government Guiding Local Science and Technology Development,China+1 种基金Project(E2022203206)supported by the Natural Science Foundation of Hebei Province,ChinaProject(241080457A)supported by the Shijiazhuang's University-Industry-Academia Cooperation Project in Hebei Province-Major Science and Technology Special Project,China。
文摘After the hot deformation sample of Ti-10V-2Fe-3Al alloy was treated by solid solution in theα+βtwo-phase region,the coarseβgrains that often appeared in theβsingle phase region were observed in the local region,indicating that the abnormal grain growth occurred in the local microstructural region,and the macrostructure also showed abnormally coarse grains(ACGs).The dynamic recrystallization(DRX)behavior of Ti-10V-2Fe-3Al titanium alloy was systematically investigated through hot compression tests on the Gleeble-3800 system.The DRX model ofβgrains was established,and the quantitative correlation between DRX characteristics and the appearance of ACG was clarified.Based on these results,a numerical simulation platform was developed to realize the visual prediction of ACG distribution.The results show that the increase of deformation temperature and the decrease of strain rate both contribute to a significant increase in the grain size(d_(DRX)))and volume fraction(X_(DRX))of DRXed grains.However,the proper X_(DRX)and smaller d_(DRX))at low deformation temperature and high strain rate make the macro and microstructure show ACGs after solid solution.Interestingly,if the DRX degree is excessive or insufficient,ACGs cannot be produced,indicating that ACGs are solid solution products based on the appropriate DRX degree.According to the flow curves and statistical results of microstructure,the quantitative model of DRX kinetics and DRX grain size model were constructed,and the quantitative criterion model that is related to the formation of ACG with grain size(d_(DRX)))and volume fraction(X_(DRX))of DRXed grains as the key parameters was established,i.e.,d_(DRX)≤2.60µm,72.5%≤X_(DRX)≤87.9%.By integrating the subroutine of coarse grain criterion,the isothermal compression process of cylindrical samples and the actual die forging process of H-shaped parts were simulated by DEFORM-3D software of finite element(FE),respectively,and the visual prediction of the distribution of macroscopic ACGs was realized.There is a good consistency between the tested results and the simulated results,indicating a strong correlation between macroscopic ACGs and microscopic DRX.
基金supported by Young Innovative Talents Training Plan of Heilongjiang(UNPYSCT-2018133).
文摘Since programing complex and dynamic heat source model for welding simulation is a complex job,the parametric methods are studied in this paper.Firstly,an overall flow to achieve automatically modeling welding was introduced.Secondly,an expert module rule for selecting welding heat source model was founded,which is based on simulation knowledge and experiences.Thirdly,a modularity routine method was investigated using writing with C++programing,which automatically creates subroutines of 3D dynamic heat source model for user.To realize the dynamic weld path,the local weld path coordinate system was moved in the global coordinate system and it is used to model the direction of weld gun,welding path and welding pose.The weld path data file was prepared by the automatic tool for the welding heat source subroutines.All above functions were integrated in the user interface and the connection with architecture was introduced.At last,a laser beam welding heat source modeling was automatically modeled and the weld pool geometry was compared with the reported literature.It demonstrated that the automated tool is valid for welding simulation.Since modeling became convenient for welding simulation using the tool proposed,it could be easy and useful for welding engineers to acquire the needed information.
基金Project (No. 0040305401042) supported by the National Natural Science Foundation of China
文摘Mucoepidermoid carcinoma undergoes uniquely vigorous angiogenic and neovascularization processes,possibly due to proliferation of vascular endothelial cells(ECs) induced by mucoepidermoid carcinoma cells(MCCs) in their three-dimensional(3D) microenvironment.To date,no studies have dealt with tumor cells and vascular ECs from the same origin of mucoepidermoid carcinoma using the in vitro 3D microenvironment model.In this context,the current research aims to observe neovascularization with mucoepidermoid carcinoma microvascular ECs(MCMECs) conditioned by the microenvironment in the 3D collagen matrix model.We observed the growth of MCMECs purified by immunomagnetic beads and induced by MCCs,and characteristics of tubule-like structures(TLSs) formed by induced MCMECs or non-induced MCMECs.The assessment parameters involved the growth curve,the length,the outer and inner diameters,and the wall thickness of the TLSs,and the cell cycle.Results showed that MCCs induced formation of the TLSs in the 3D collagen matrix model.A statistically significant difference was noted regarding the count of TLSs between the control group and the induction group on the 4th day of culture(t=5.00,P=0.001).The outer and inner diameters(t1=5.549,P1=0.000;t2=10.663,P2=0.000) and lengths(t=18.035,P=0.000) of the TLSs in the induction group were statistically significant larger than those in the control group.The TLSs were formed at the earlier time in the induction group compared with the control group.It is concluded that MCCs promote growth and migration of MCMECs,and formation of the TLSs.The 3D collagen matrix model with MCMECs induced by MCCs in the current research may be a favorable choice for research on pro-angiogenic factors in progression of mucoepidermoid carcinoma.
文摘Lie symmetry analysis is applied to a(3+1)-dimensional Virasoro integrable model and the corresponding similarity reduction equations are obtained with the different infinitesimal generators.Invariant solutions with arbitrary functions for the(3+1)-dimensional Virasoro integrable model,including the interaction solution between a kink and a soliton,the lump-type solution and periodic solutions,have been studied analytically and graphically.
文摘The summer and winter circulations in the South China Sea (SCS) including the surface elevation and water temperature are simulated using the model described by Cai and Li (1996) with the monthly mean wind stress and air temperature field at the 1000 mb level from the European Centre for Medium-Range Weather Forecasts as inputs. The boundary conditions at Bashi Channel and Taiwan Strait are taken from the simulation results of the Kuroshio using the same numerical model with a grid size of 0.5°×0.5° and the results of Cai and Li (1996) as boundary conditions. The computational domain for the present paper is between 100°E and 123°E and between 4.5°N and 27°N. The horizontal resolution is 0.25°×0.25° and the vertical variations of the velocity components are resolved by 6 layers The computed steady flow, temperature and elevation fields are consistent with the corresponding fields observed. In particular, the temperature and elevation fields of the South China Sea Warm Current (SCSWC) have been successfully simulated. The paths of the branch of the Kuroshio entering the South China Sea (SCSBK) through Bashi Channel in winter and summer are discussed It is found that the SCSBK flows southward to the southern SCS from the coast of the Guangdong Province. A portion of the SCSBK returns to the Bashi Channel and subdivides again in deep waters in winter with a branch flows to the south along the coast of the Philippines instead of flowing back to the Pacific In addition, our results confirm the existence of a eastward current to the northeast of Dongsha in summer with the Kuroshio as its source as suggested by Huang et al. Since the value of the eddy viscosity adopted for the simulation of the Kuroshio is on the high side, resulting in a weaker west boundary current in the western Pacific as the boundary conditions for the present simulations, some deviations from the actual situations are expected although the results are in general consistent with observations.
基金Supported by the National Natural Science Foundation of China under Grant No.10974177by the Ministry of Science and Technology of China under Grant No.2010DFA04690
文摘We obtain exact spatiotemporal similaritons to a （3＋ l）-dimensional inhomogeneous nonlinear Schrodinger equation, which describes the propagation of optical pulses in a cubic-quintic nonlinearity medium with distributed dispersion and gain. A one-to-one correspondence between such self-similar waves and solutions of the elliptic equation is found when a certain compatibility condition is satisfied. Based on exact solutions, we discuss evolutional behaviors of self-similar cnoidal waves and chirped similaritons in two kind of typicai soliton control systems. Moreover, the comparison between chirped similaritons and chirp-free solitons is given.
基金the financial supports from the National Natural Science Foundation of China (Nos. 52001163, 52075237)the Primary Research and Development Plan of Jiangsu Province, China (No. BE2019119)
文摘Hot deformation behaviors and microstructure evolution of Ti-3Al-5Mo-4Cr-2Zr-1Fe(Ti-35421)alloy in theβsingle field are investigated by isothermal compression tests on a Gleeble-3500 simulator at temperatures of 820-900°C and strain rates of 0.001-1 s^(-1).The research results show that discontinuous yield phenomenon and rheological softening are affected by the strain rates and deformation temperatures.The critical conditions for dynamic recrystallization and kinetic model of Ti-35421 alloy are determined,and the Arrhenius constitutive model is constructed.The rheological behaviors of Ti-35421 alloys aboveβphase transformation temperature are predicted by the constitutive model accurately.The EBSD analysis proves that the deformation softening is controlled by dynamic recovery and dynamic recrystallization.In addition,continuous dynamic recrystallization is determined during hot deformation,and the calculation model for recrystallization grain sizes is established.Good linear dependency between the experimental and simulated values of recrystallized grain sizes indicates that the present model can be used for the prediction of recrystallized grain size with high accuracy.
基金supported by the National Natural Science Foundation of China (Grant Nos.52004182, 51908431)。
文摘Rockslides are one of the most common geological hazards in mountainous areas and can pose significant threats to the safety of human lives and infrastructures. Studying the dynamic fragmentation process, and fragment characteristics of rock blocks during rockslides is of great significance. In this study,the influences of the slope angle on the dynamic fragmentation process, damage and energy evolution,and the fragments’ flying velocity and flying angle were systematically investigated using a coupled 3D FEM-DEM method. An improved fragment search algorithm was first proposed to more effectively extract the information of the fragments after impacting. The input parameters in the numerical modeling were carefully calibrated based on the quasi-static uniaxial compression tests and the rockimpact tests. The complex fragmentation process of rock block sliding along an inclined slope was simulated. The results indicate that the fragmentation intensity gradually increases with increasing the slope angle, and the fragmentation intensity of the front region of the rock block is always higher than that of the rear region. Additionally, the slope angle can significantly affect the damage ratio, energy dissipation, and the ratio of tensile crack to shear crack during the rockslides. The number of the fragments having higher flying velocities and larger flying angles increases with increasing the slope angle,which contributes to a larger spreading distance and a wider deposition area.
文摘Based on computer graphics principle, technology and 3D graphics software, this paper deals with the 3D part design, assembly and animation of shearer in longwall integrated mechanized coal mining. The matixes of kinetic and geometry relationships and 3 dimension space coordinate systems are built for the cut drums, arms and shearer body. The methods of 3D modeling, dynamic simulation and relative technique problems are discussed.
基金Project supported by the National Key R&D Program of China(Grant No.2017YFE0120500)the National Natural Science Foundation of China(Grant No.51972129)+3 种基金the South Xinjiang Innovation and Development Program of Key Industries of Xinjiang Production and Construction Corps(Grant No.2020DB002)the Fundamental Research Funds for the Central Universities,China(Grant Nos.HUST 2018KFYYXJJ051 and 2019KFYXMBZ076)Shenzhen Fundamental Research Fund(Grant No.JCYJ20190813172609404)the Hubei“Chu-Tian Young Scholar”Program。
文摘The dynamic phase transition properties for ferroelectric nanotube under a spin-1/2 transverse Ising model are studied under the effective field theory(EFT)with correlations.The temperature effects on the pseudo-spin systems are unveiled in three-dimensional(3-D)and two-dimensional(2-D)phase diagrams.Moreover,the dynamic behaviors of exchange interactions on the 3-D and 2-D phase transitions under high temperature are exhibited.The results present that it is hard to obtain pure ferroelectric phase under high temperature;that is,the vibration of orderly pseudo-spins cannot be eliminated completely.
基金Supported by the National Natural Science Foundation of China(11661060)Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT-20-A06)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2018LH01013).
文摘In this paper,we give the general interaction solution to the(3+1)-dimensional Jimbo–Miwa equation.The general interaction solution contains the classical interaction solution.As an example,by using the generalized bilinear method and symbolic computation by using Maple software,novel interaction solutions under certain constraints of the(3+1)-dimensional Jimbo–Miwa equation are obtained.Via three-dimensional plots,contour plots and density plots with the help of Maple,the physical characteristics and structures of these waves are described very well.These solutions greatly enrich the exact solutions to the(3+1)-dimensional Jimbo–Miwa equation found in the existing literature.
基金Supported by the Applied Nonlinear Science and Technology from the Most Important Among all the Top Priority Disciplines of Zhejiang Province
文摘We construct analytical self-similar solutions for the generalized (3+1)-dimensional nonlinear Schrdinger equation with polynomial nonlinearity of arbitrary order. As an example, we list self-similar solutions of quintic nonlinear Schrdinger equation with distributed dispersion and distributed linear gain, including bright similariton solution, fractional and combined Jacobian elliptic function solutions. Moreover, we discuss self-similar evolutional dynamic behaviors of these solutions in the dispersion decreasing fiber and the periodic distributed amplification system.
