In this work,an Ⅱ-Ⅵ group semiconductor zinc telluride(ZnTe) single crystal is prepared by a novel vertical Bridgman method using Te as flux.The initial mole ratio of Zn/Te=3:7 is designed for raw material synthesis...In this work,an Ⅱ-Ⅵ group semiconductor zinc telluride(ZnTe) single crystal is prepared by a novel vertical Bridgman method using Te as flux.The initial mole ratio of Zn/Te=3:7 is designed for raw material synthesis.ZnTe polycrystalline combined with rich Te is effectively fabricated through rocking technique at 1100℃.A Φ 25 mm × 65 mm ZnTe boule is successfully grown under a~40 ℃·cm^(-1) temperature gradient with a growth speed of 5 mm·day^(-1).The as-grown ZnTe crystal has a standard 1:1 stoichiometric ratio and pure F43 m phase structure.The maximum transmittance perpendicular to(110) plane is about 64%,and the band gap(E_(g)) is tested to be 2.225 eV.Terahertz(THz) examination results demonstrate that the time of the highest THz signal is around 17 ps and the frequency of the highest THz transmission is about 0.78 THz,implying that the ZnTe crystal grown by the present Te flux vertical Bridgman method has a good feasibility for THz application.展开更多
In the present work, the improved version of the meshless singular boundary method(ISBM) is developed for analyzing the performance of bottom standing submerged permeable breakwaters in regular normally incident waves...In the present work, the improved version of the meshless singular boundary method(ISBM) is developed for analyzing the performance of bottom standing submerged permeable breakwaters in regular normally incident waves and in the proximity of a vertical wall. Both single and dual prismatic breakwaters of rectangular and trapezoidal forms are examined. The physical problem is cast in terms of the Laplace equation governing an irrotational flow and incompressible fluid motion with appropriate mixed type boundary conditions, and solved numerically using the ISBM. To model the permeability of the breakwaters fully absorbing boundary conditions are assumed. Numerical results are presented in terms of hydrodynamic quantities of the reflection coefficients. These are firstly validated against the results of a multi-domain boundary element method(BEM) developed independently for a previous study. The agreement between the results of the two methods is excellent. The coefficients of reflection are then computed and discussed for a variety of structural conditions including the breakwaters height, width, spacing, and absorbing permeability. Effects of the proximity of the vertical plane wall are also investigated. The breakwater's width is found to have only marginal effects compared with its height. Permeability tends to decrease the minimum reflections. These coefficients show periodic variations with the spacing relative to the wavelength. Trapezoidal breakwaters are found to be more cost-effective than the rectangular breakwaters. Dual breakwater systems are confirmed to perform much better than single structures.展开更多
In this paper,a scheme of dual-Doppler radar wind analysis based on a three-dimensional variational method is proposed and performed in two steps.First,the horizontal wind field is simultaneously recovered through min...In this paper,a scheme of dual-Doppler radar wind analysis based on a three-dimensional variational method is proposed and performed in two steps.First,the horizontal wind field is simultaneously recovered through minimizing a cost function defined as a radial observation term with the standard conjugate gradient method,avoiding a weighting parameter specification step.Compared with conventional dual-Doppler wind synthesis approaches,this variational method minimizes errors caused by interpolation from radar observation to analysis grid in the iterative solution process,which is one of the main sources of errors.Then,through the accelerated Liebmann method,the vertical velocity is further reestimated as an extra step by solving the Poisson equation with impermeable conditions imposed at the ground and near the tropopause.The Poisson equation defined by the second derivative of the vertical velocity is derived from the mass continuity equation.Compared with the method proposed by O’Brien,this method is less sensitive to the uncertainty of the boundary conditions and has better stability and reliability.Furthermore,the method proposed in this paper is applied to Doppler radar observation of a squall line process.It is shown that the retrieved vertical wind profile agrees well with the vertical profile obtained with the velocity–azimuth display(VAD)method,and the retrieved radial velocity as well as the analyzed positive and negative velocity centers and horizontal wind shear of the squall line are in accord with radar observations.There is a good correspondence between the divergence field of the derived wind field and the vertical velocity.And,the horizontal and vertical circulations within and around the squall line,as well as strong updrafts,the associated downdrafts,and associated rear inflow of the bow echo,are analyzed well.It is worth mentioning that the variational method in this paper can be applied to simultaneously synthesize the three-dimensional wind field from multiple-Doppler radar observations.展开更多
Optical absorption,excitation,and fluorescence were investigated in Eu ion-doped CdWO4 single crystal grown by a modified Bridgman method.The results indicate that Eu2+ and Eu3+ ions coexist in CdWO4 crystal and an en...Optical absorption,excitation,and fluorescence were investigated in Eu ion-doped CdWO4 single crystal grown by a modified Bridgman method.The results indicate that Eu2+ and Eu3+ ions coexist in CdWO4 crystal and an energy transfer occurs between these Eu2+ and Eu3+ ions.When the crystal is excited by 266-nm light,the energy corresponding to the 4f65d to 8S7/2 transition of Eu2+ ions results in the excitation of the Eu3+ ions to the 5DJ level.The effect on fluorescence of annealing in oxygen at various temperatures was investigated.The excitation intensity of Eu2+ ions at 266 nm decreases as annealing temperature increases from 300 K to 1073 K,but it remains at a certain equilibrium level when the annealing temperature is further increased.展开更多
A numerical method capable is developed for handling steady laminar flow and heat trans-fer of a highly viscous power-law fluid whose density,viscosity,specific heat and thermalconductivity,vary with temperature.The g...A numerical method capable is developed for handling steady laminar flow and heat trans-fer of a highly viscous power-law fluid whose density,viscosity,specific heat and thermalconductivity,vary with temperature.The governing equations are found to be continuity,monmentumand energy expressions.Important effects such as varying viscosity,natural convection and viscousdissipation are incorporated in the theoretical model.These equations are being attracted by employing a decoupled finite element method.Galerkin’sprinciple is used to handle the momentum and continuity equations.Consistent(SU/PG)andnon-consistent(SU)streamline upwind methods are employed for the energy equation.Comparisonof calculated results and experimental data shows good agreement.Similar results are obtained withSU and SU/PG methods.Velocity and temperature profiles which provide insights into the processare also given.展开更多
All-vertical-piled wharf is a kind of high-piled wharf,but it is extremely different from the traditional ones in some aspects,such as the structural property,bearing characteristics,failure mechanism,and static or dy...All-vertical-piled wharf is a kind of high-piled wharf,but it is extremely different from the traditional ones in some aspects,such as the structural property,bearing characteristics,failure mechanism,and static or dynamic calculation methods.In this paper,the finite element method(FEM) and theoretical analysis method are combined to analyze the structural property,bearing behavior and failure mode of the all-vertical-piled wharf in offshore deep water,and to establish simplified calculation methods determining the horizontal static ultimate bearing capacity and the dynamic response for the all-vertical-piled wharf.Firstly,the bearing capability and failure mechanism for all-vertical-piled wharf are studied by use of FEM,and the failure criterion is put forward for all-vertical-piled wharf based on the'plastic hinge'.According to the failure criterion and P-Y curve method,the simplified calculation method of the horizontal static ultimate bearing capacity for all-vertical-piled wharf is proposed,and it is verified that the simplified method is reasonable by comparison with the FEM.Secondly,the displacement dynamic magnification factor for the all-vertical-piled wharf under wave cyclic loads and ship impact loads is calculated by the FEM and the theory formula based on the single degree of freedom(SDOF) system.The results obtained by the two methods are in good agreement with each other,and the simplified calculation method of the displacement dynamic magnification factor for all-vertical-piled wharf under dynamic loads is proposed.Then the simplified calculation method determining the dynamic response for the all-vertical-piled wharf is proposed in combination with P-Y curve method.That is,the dynamic response of the structure can be obtained through the static calculation results of P-Y curve method multiplied by the displacement dynamic magnification factor.The feasibility of the simplified dynamic response method is verified by comparison with the FEM under different conditions.展开更多
There has been a growing trend in the development of offshore deep-water ports in China. For such deep sea projects, all-vertical-piled wharves are suitable structures and generally located in open waters, greatly aff...There has been a growing trend in the development of offshore deep-water ports in China. For such deep sea projects, all-vertical-piled wharves are suitable structures and generally located in open waters, greatly affected by wave action. Currently, no systematic studies or simplified numerical methods are available for deriving the dynamic characteristics and dynamic responses of all-vertical-piled wharves under wave cyclic loads. In this article, we compare the dynamic characteristics of an all-vertical-piled wharf with those of a traditional inshore high-piled wharf through numerical analysis; our research reveals that the vibration period of an all-vertical-piled wharf under cyclic loading is longer than that of an inshore high-piled wharf and is much closer to the period of the loading wave. Therefore, dynamic calculation and analysis should be conducted when designing and calculating the characteristics of an all-vertical-piled wharf. We establish a dynamic finite element model to examine the dynamic response of an all-vertical-piled wharf under wave cyclic loads and compare the results with those under wave equivalent static load; the comparison indicates that dynamic amplification of the structure is evident when the wave dynamic load effect is taken into account. Furthermore, a simplified dynamic numerical method for calculating the dynamic response of an all-vertical-piled wharf is established based on the P-Y curve. Compared with finite element analysis, the simplified method is more convenient to use and applicable to large structural deformation while considering the soil non-linearity. We confirmed that the simplified method has acceptable accuracy and can be used in engineering applications.展开更多
In this research,a vertical channel containing a laminar and fully developed nanofluid flow is investigated.The channel surface’s boundary conditions for temperature and volume fraction functions are considered qth-o...In this research,a vertical channel containing a laminar and fully developed nanofluid flow is investigated.The channel surface’s boundary conditions for temperature and volume fraction functions are considered qth-order polynomials.The equations related to this problem have been extracted and then solved by the AGM and validated through the Runge-Kutta numerical method and another similar study.In the study,the effect of parameters,including Grashof number,Brownian motion parameter,etc.,on the motion,velocity,temperature,and volume fraction of nanofluids have been analyzed.The results demonstrate that increasing the Gr number by 100%will increase the velocity profile function by 78%and decrease the temperature and fraction profiles by 20.87%and 120.75%.Moreover,rising the Brownian motion parameter in five different sizes(0.1,0.2,0.3,0.4,and 0.5)causes lesser velocity,about 24.3%at first and 4.35%at the last level,and a maximum 52.86%increase for temperature and a 24.32%rise for ψ occurs when N b rises from 0.1 to 0.2.For all N_(t) values,at least 55.44%,18.69%,for F(η),andΩ(η),and 20.23%rise for ψ(η)function is observed.Furthermore,enlarging the N r parameter from 0.25 to 0.1 leads F(η)to rise by 199.7%,fluid dimensionless temperature,and dimensional volume fraction to decrease by 18%and 92.3%.In the end,a greater value of q means a more powerful energy source,amplifying all velocity,temperature,and volume fraction functions.The main novelty of this research is the combined convection qth-order polynomials boundary condition applied to the channel walls.Moreover,The AMG semi-analytical method is used as a novel method to solve the governing equations.展开更多
Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical a...Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical absorption spectroscopy(MAX-DOAS)technology is established for retrieving the tropospheric NO_(2) vertical distribution profiles.This method retrieves the aerosol extinction profiles with minimum cost function.Then,the aerosol extinction profiles and the atmospheric radiation transfer model(RTM)are employed to establish the look-up table for retrieving the NO_(2) vertical column densities(VCDs)and profiles.The measured NO_(2) differential slant column densities(DSCDs)are compared with the NO_(2) DSCDs simulated by the atmospheric RTM,and the NO_(2) VCDs,the weight factor of NO_(2) in the boundary layer,and the boundary layer height are obtained by the minimization process.The look-up table is established to retrieve NO_(2) VCDs based on MAX-DOAS measurements in Huaibei area,and the results are compared with the data from Copernicus Atmospheric Monitoring Service(CAMS)model.It is found that there are nearly consistent and the correlation coefficient R2 is more than 0.86.The results show that this technology provides a more convenient and accurate retrieval method for the stereoscopic monitoring of atmospheric environment.展开更多
The growth of LiNbO3 single crystal with Er 3+/Zn 2+ co-doped by the bridgman method and the characteristics of absorption spectra and fluorescence spectra were reported. By means of the optimized conditions such as g...The growth of LiNbO3 single crystal with Er 3+/Zn 2+ co-doped by the bridgman method and the characteristics of absorption spectra and fluorescence spectra were reported. By means of the optimized conditions such as growth rate of 0.8～1.5 mm·h -1, temperature gradient about 30～35 ℃·cm -1 across the solid-liquid interface and sealed platinum, large size crystals containing Zn 2+ （3%） and Er 3+ （0.6%） with good optical quality were obtained. X-ray diffraction and DTA were used to characterize the crystals. The results indicate that the concentration of Er 3+ ions in crystals decrease along the growth direction, the absorption intensity and the fluorescence intensity of Er 3+ ions also decrease along the growth direction. However, for the upper part crystal, the upconversion fluorescence intensity is higher than that of the lower part crystal excited with 800 or 970 nm pump. The effects of crystal lattice, structure defect and effective segregation of Er 3+ ions were discussed in respect to the variations were discussed of upconversion fluorescence intensity.展开更多
Diapycnal mixing is important in oceanic circulation. An inverse method in which a semi-explicit scheme is applied to discretize the one-dimensional temperature diffusion equation is established to estimate the vertic...Diapycnal mixing is important in oceanic circulation. An inverse method in which a semi-explicit scheme is applied to discretize the one-dimensional temperature diffusion equation is established to estimate the vertical temperature diffusion coefficient based on the observed temperature profiles. The sensitivity of the inverse model in the idealized and actual conditions is tested in detail. It can be found that this inverse model has high feasibility under multiple situations ensuring the stability of the inverse model, and can be considered as an efficient way to estimate the temperature diffusion coefficient in the weak current regions of the ocean. Here, the hydrographic profiles from Argo floats are used to estimate the temporal and spatial distribution of the vertical mixing in the north central Pacific based on this inverse method. It is further found that the vertical mixing in the upper ocean displays a distinct seasonal variation with the amplitude decreasing with depth, and the vertical mixing over rough topography is stronger than that over smooth topography. It is suggested that the high-resolution profiles from Argo floats and a more reasonable design of the inverse scheme will serve to understand mixing processes.展开更多
The damage of the overburden is a complex nonliear mechanical problem. To immediately master the stress state of the vertical shaft in process of the damage of overburden, and protect the shaft, in this paper, a serie...The damage of the overburden is a complex nonliear mechanical problem. To immediately master the stress state of the vertical shaft in process of the damage of overburden, and protect the shaft, in this paper, a series of new type of rock mass stress and strain compatible sensors are used. The vertical shaft wall mechanical parameter and surrounding mechanical parameter are calculated by the result of the measurement. A set of the calculation method of the vertical shaft and surrounding rock parameter are defined.展开更多
A one_step smoothing Newton method is proposed for solving the vertical linear complementarity problem based on the so_called aggregation function. The proposed algorithm has the following good features: (ⅰ) It solve...A one_step smoothing Newton method is proposed for solving the vertical linear complementarity problem based on the so_called aggregation function. The proposed algorithm has the following good features: (ⅰ) It solves only one linear system of equations and does only one line search at each iteration; (ⅱ) It is well_defined for the vertical linear complementarity problem with vertical block P 0 matrix and any accumulation point of iteration sequence is its solution.Moreover, the iteration sequence is bounded for the vertical linear complementarity problem with vertical block P 0+R 0 matrix; (ⅲ) It has both global linear and local quadratic convergence without strict complementarity. Many existing smoothing Newton methods do not have the property (ⅲ).展开更多
The study of wave propagation in finite/infinite media has many applications in geotechnical and structural earthquake engineering and has been a focus of research for the past few decades.This paper presents an analy...The study of wave propagation in finite/infinite media has many applications in geotechnical and structural earthquake engineering and has been a focus of research for the past few decades.This paper presents an analysis of 2D antiplane problems(Love waves)and 2D in-plane problems(Rayleigh waves)in the frequency domain in media consisting of a near-field irregular and a far-field regular part.The near field part may contain structures and its boundaries with the far-field can be of any shape.In this study,the irregular boundaries of the near-field are treated as consistent boundaries,extending the concept of Lysmer’s vertical consistent boundaries.The presented technique is called the Condensed Hyperelements Method(CHM).In this method,the irregular boundary is limited to a vertical boundary at each end that is a consistent boundary at the far-field side.Between the two ends,the medium is discretized with hyperelements.Using static condensation,the stiffness matrix of the far-field is derived for the nodes on the irregular boundary.Examples of the application of the CHM illustrate its excellent accuracy and efficiency.展开更多
Based on the flow mechanism of hydraulic fractured wells, through integrating linear-flow model and effective well-radius model, a new model of well test analysis for wells with vertical fracture was established. In t...Based on the flow mechanism of hydraulic fractured wells, through integrating linear-flow model and effective well-radius model, a new model of well test analysis for wells with vertical fracture was established. In the model, wellbore storage, the damage in the wall of fracture and all kinds of boundary conditions are considered. The model is concise in form, has intact curves and computes fast, which may meet the demand of real-time computation and fast responded well test interpretation. A new method to determine effective well radius was presented, and the correlation between effective well radius and the fracture length, fracture conductivity, skin factor of fracture was given. Matching flow rate or pressure tested, the optimization model that identified formation and fracture parameters was set up. The automatic matching method was presented by synthetically using step by step linear least square method and sequential quadratic programming. At last, the application was also discussed. Application shows that all of these results can analyze and evaluate the fracturing treatment quality scientifically and rationally, instruct and modify the design of fracturing and improve fracturing design level.展开更多
基金financially supported by the Natural Science Foundation of Shanghai(Nos.19ZR1419900,19ZR1420100)Shanghai Engineering Research Center of Hot Manufacturing(No.18DZ2253400)。
文摘In this work,an Ⅱ-Ⅵ group semiconductor zinc telluride(ZnTe) single crystal is prepared by a novel vertical Bridgman method using Te as flux.The initial mole ratio of Zn/Te=3:7 is designed for raw material synthesis.ZnTe polycrystalline combined with rich Te is effectively fabricated through rocking technique at 1100℃.A Φ 25 mm × 65 mm ZnTe boule is successfully grown under a~40 ℃·cm^(-1) temperature gradient with a growth speed of 5 mm·day^(-1).The as-grown ZnTe crystal has a standard 1:1 stoichiometric ratio and pure F43 m phase structure.The maximum transmittance perpendicular to(110) plane is about 64%,and the band gap(E_(g)) is tested to be 2.225 eV.Terahertz(THz) examination results demonstrate that the time of the highest THz signal is around 17 ps and the frequency of the highest THz transmission is about 0.78 THz,implying that the ZnTe crystal grown by the present Te flux vertical Bridgman method has a good feasibility for THz application.
基金financially supported by the Direction Général des Enseignements et de la Formation Supérieure of Algeria(Grant CNEPRU No.G0301920140029)
文摘In the present work, the improved version of the meshless singular boundary method(ISBM) is developed for analyzing the performance of bottom standing submerged permeable breakwaters in regular normally incident waves and in the proximity of a vertical wall. Both single and dual prismatic breakwaters of rectangular and trapezoidal forms are examined. The physical problem is cast in terms of the Laplace equation governing an irrotational flow and incompressible fluid motion with appropriate mixed type boundary conditions, and solved numerically using the ISBM. To model the permeability of the breakwaters fully absorbing boundary conditions are assumed. Numerical results are presented in terms of hydrodynamic quantities of the reflection coefficients. These are firstly validated against the results of a multi-domain boundary element method(BEM) developed independently for a previous study. The agreement between the results of the two methods is excellent. The coefficients of reflection are then computed and discussed for a variety of structural conditions including the breakwaters height, width, spacing, and absorbing permeability. Effects of the proximity of the vertical plane wall are also investigated. The breakwater's width is found to have only marginal effects compared with its height. Permeability tends to decrease the minimum reflections. These coefficients show periodic variations with the spacing relative to the wavelength. Trapezoidal breakwaters are found to be more cost-effective than the rectangular breakwaters. Dual breakwater systems are confirmed to perform much better than single structures.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFC1510400)the National Natural Science Foundation of China(Grant Nos.41975054 and 41930967)the Special Fund for Forecasters of China Meteorological Administration(Grant No.CMAYBY2018-040)。
文摘In this paper,a scheme of dual-Doppler radar wind analysis based on a three-dimensional variational method is proposed and performed in two steps.First,the horizontal wind field is simultaneously recovered through minimizing a cost function defined as a radial observation term with the standard conjugate gradient method,avoiding a weighting parameter specification step.Compared with conventional dual-Doppler wind synthesis approaches,this variational method minimizes errors caused by interpolation from radar observation to analysis grid in the iterative solution process,which is one of the main sources of errors.Then,through the accelerated Liebmann method,the vertical velocity is further reestimated as an extra step by solving the Poisson equation with impermeable conditions imposed at the ground and near the tropopause.The Poisson equation defined by the second derivative of the vertical velocity is derived from the mass continuity equation.Compared with the method proposed by O’Brien,this method is less sensitive to the uncertainty of the boundary conditions and has better stability and reliability.Furthermore,the method proposed in this paper is applied to Doppler radar observation of a squall line process.It is shown that the retrieved vertical wind profile agrees well with the vertical profile obtained with the velocity–azimuth display(VAD)method,and the retrieved radial velocity as well as the analyzed positive and negative velocity centers and horizontal wind shear of the squall line are in accord with radar observations.There is a good correspondence between the divergence field of the derived wind field and the vertical velocity.And,the horizontal and vertical circulations within and around the squall line,as well as strong updrafts,the associated downdrafts,and associated rear inflow of the bow echo,are analyzed well.It is worth mentioning that the variational method in this paper can be applied to simultaneously synthesize the three-dimensional wind field from multiple-Doppler radar observations.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 50972061,51272109,and 21171102)the Natural Science Foundation of Zhejiang Province of China (Grant Nos. R4100364 and Z4110072)+1 种基金the Natural Science Foundation of Ningbo City (Grant No. 2012A610115)K. C.Wong Magna Fund in Ningbo University
文摘Optical absorption,excitation,and fluorescence were investigated in Eu ion-doped CdWO4 single crystal grown by a modified Bridgman method.The results indicate that Eu2+ and Eu3+ ions coexist in CdWO4 crystal and an energy transfer occurs between these Eu2+ and Eu3+ ions.When the crystal is excited by 266-nm light,the energy corresponding to the 4f65d to 8S7/2 transition of Eu2+ ions results in the excitation of the Eu3+ ions to the 5DJ level.The effect on fluorescence of annealing in oxygen at various temperatures was investigated.The excitation intensity of Eu2+ ions at 266 nm decreases as annealing temperature increases from 300 K to 1073 K,but it remains at a certain equilibrium level when the annealing temperature is further increased.
文摘A numerical method capable is developed for handling steady laminar flow and heat trans-fer of a highly viscous power-law fluid whose density,viscosity,specific heat and thermalconductivity,vary with temperature.The governing equations are found to be continuity,monmentumand energy expressions.Important effects such as varying viscosity,natural convection and viscousdissipation are incorporated in the theoretical model.These equations are being attracted by employing a decoupled finite element method.Galerkin’sprinciple is used to handle the momentum and continuity equations.Consistent(SU/PG)andnon-consistent(SU)streamline upwind methods are employed for the energy equation.Comparisonof calculated results and experimental data shows good agreement.Similar results are obtained withSU and SU/PG methods.Velocity and temperature profiles which provide insights into the processare also given.
基金financially supported by the Education Commission Fund of Chongqing(Grant No.KJ1500518)the Science Commission Fund of Chongqing(Grant No.cstc2016jcyjA0123)the Open Fund of Key Laboratory of Regulation Technology for Inland Waterway in Transportation Industry of Chongqing Jiaotong University(Grant No.NHHD-201506)
文摘All-vertical-piled wharf is a kind of high-piled wharf,but it is extremely different from the traditional ones in some aspects,such as the structural property,bearing characteristics,failure mechanism,and static or dynamic calculation methods.In this paper,the finite element method(FEM) and theoretical analysis method are combined to analyze the structural property,bearing behavior and failure mode of the all-vertical-piled wharf in offshore deep water,and to establish simplified calculation methods determining the horizontal static ultimate bearing capacity and the dynamic response for the all-vertical-piled wharf.Firstly,the bearing capability and failure mechanism for all-vertical-piled wharf are studied by use of FEM,and the failure criterion is put forward for all-vertical-piled wharf based on the'plastic hinge'.According to the failure criterion and P-Y curve method,the simplified calculation method of the horizontal static ultimate bearing capacity for all-vertical-piled wharf is proposed,and it is verified that the simplified method is reasonable by comparison with the FEM.Secondly,the displacement dynamic magnification factor for the all-vertical-piled wharf under wave cyclic loads and ship impact loads is calculated by the FEM and the theory formula based on the single degree of freedom(SDOF) system.The results obtained by the two methods are in good agreement with each other,and the simplified calculation method of the displacement dynamic magnification factor for all-vertical-piled wharf under dynamic loads is proposed.Then the simplified calculation method determining the dynamic response for the all-vertical-piled wharf is proposed in combination with P-Y curve method.That is,the dynamic response of the structure can be obtained through the static calculation results of P-Y curve method multiplied by the displacement dynamic magnification factor.The feasibility of the simplified dynamic response method is verified by comparison with the FEM under different conditions.
基金financially supported by the Major Science and Technology Project of MOT,China(Grant Nos.2013 328 224 070 and 2014 328 224 040)the National Natural Science Foundation of China(Grant No.51409134)
文摘There has been a growing trend in the development of offshore deep-water ports in China. For such deep sea projects, all-vertical-piled wharves are suitable structures and generally located in open waters, greatly affected by wave action. Currently, no systematic studies or simplified numerical methods are available for deriving the dynamic characteristics and dynamic responses of all-vertical-piled wharves under wave cyclic loads. In this article, we compare the dynamic characteristics of an all-vertical-piled wharf with those of a traditional inshore high-piled wharf through numerical analysis; our research reveals that the vibration period of an all-vertical-piled wharf under cyclic loading is longer than that of an inshore high-piled wharf and is much closer to the period of the loading wave. Therefore, dynamic calculation and analysis should be conducted when designing and calculating the characteristics of an all-vertical-piled wharf. We establish a dynamic finite element model to examine the dynamic response of an all-vertical-piled wharf under wave cyclic loads and compare the results with those under wave equivalent static load; the comparison indicates that dynamic amplification of the structure is evident when the wave dynamic load effect is taken into account. Furthermore, a simplified dynamic numerical method for calculating the dynamic response of an all-vertical-piled wharf is established based on the P-Y curve. Compared with finite element analysis, the simplified method is more convenient to use and applicable to large structural deformation while considering the soil non-linearity. We confirmed that the simplified method has acceptable accuracy and can be used in engineering applications.
文摘In this research,a vertical channel containing a laminar and fully developed nanofluid flow is investigated.The channel surface’s boundary conditions for temperature and volume fraction functions are considered qth-order polynomials.The equations related to this problem have been extracted and then solved by the AGM and validated through the Runge-Kutta numerical method and another similar study.In the study,the effect of parameters,including Grashof number,Brownian motion parameter,etc.,on the motion,velocity,temperature,and volume fraction of nanofluids have been analyzed.The results demonstrate that increasing the Gr number by 100%will increase the velocity profile function by 78%and decrease the temperature and fraction profiles by 20.87%and 120.75%.Moreover,rising the Brownian motion parameter in five different sizes(0.1,0.2,0.3,0.4,and 0.5)causes lesser velocity,about 24.3%at first and 4.35%at the last level,and a maximum 52.86%increase for temperature and a 24.32%rise for ψ occurs when N b rises from 0.1 to 0.2.For all N_(t) values,at least 55.44%,18.69%,for F(η),andΩ(η),and 20.23%rise for ψ(η)function is observed.Furthermore,enlarging the N r parameter from 0.25 to 0.1 leads F(η)to rise by 199.7%,fluid dimensionless temperature,and dimensional volume fraction to decrease by 18%and 92.3%.In the end,a greater value of q means a more powerful energy source,amplifying all velocity,temperature,and volume fraction functions.The main novelty of this research is the combined convection qth-order polynomials boundary condition applied to the channel walls.Moreover,The AMG semi-analytical method is used as a novel method to solve the governing equations.
基金the National Natural Science Foundation of China(Grant No.41875040)the Top-notch Talents Program in Universities of Anhui Province,China(Grant No.gxbjZD2020067)the Natural Science Research Projects of Universities in Anhui Province,China(Grant No.KJ2020A0029).
文摘Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical absorption spectroscopy(MAX-DOAS)technology is established for retrieving the tropospheric NO_(2) vertical distribution profiles.This method retrieves the aerosol extinction profiles with minimum cost function.Then,the aerosol extinction profiles and the atmospheric radiation transfer model(RTM)are employed to establish the look-up table for retrieving the NO_(2) vertical column densities(VCDs)and profiles.The measured NO_(2) differential slant column densities(DSCDs)are compared with the NO_(2) DSCDs simulated by the atmospheric RTM,and the NO_(2) VCDs,the weight factor of NO_(2) in the boundary layer,and the boundary layer height are obtained by the minimization process.The look-up table is established to retrieve NO_(2) VCDs based on MAX-DOAS measurements in Huaibei area,and the results are compared with the data from Copernicus Atmospheric Monitoring Service(CAMS)model.It is found that there are nearly consistent and the correlation coefficient R2 is more than 0.86.The results show that this technology provides a more convenient and accurate retrieval method for the stereoscopic monitoring of atmospheric environment.
文摘The growth of LiNbO3 single crystal with Er 3+/Zn 2+ co-doped by the bridgman method and the characteristics of absorption spectra and fluorescence spectra were reported. By means of the optimized conditions such as growth rate of 0.8～1.5 mm·h -1, temperature gradient about 30～35 ℃·cm -1 across the solid-liquid interface and sealed platinum, large size crystals containing Zn 2+ （3%） and Er 3+ （0.6%） with good optical quality were obtained. X-ray diffraction and DTA were used to characterize the crystals. The results indicate that the concentration of Er 3+ ions in crystals decrease along the growth direction, the absorption intensity and the fluorescence intensity of Er 3+ ions also decrease along the growth direction. However, for the upper part crystal, the upconversion fluorescence intensity is higher than that of the lower part crystal excited with 800 or 970 nm pump. The effects of crystal lattice, structure defect and effective segregation of Er 3+ ions were discussed in respect to the variations were discussed of upconversion fluorescence intensity.
基金The Program for New Century Excellent Talents in University of the Ministry of Education under contract No.NCET-10-0764the National High Technology Research and Development Program of China(863 Program)under contract No.2013AA09A502the National Natural Science Foundation of China under contract Nos 40876015 and 41176010
文摘Diapycnal mixing is important in oceanic circulation. An inverse method in which a semi-explicit scheme is applied to discretize the one-dimensional temperature diffusion equation is established to estimate the vertical temperature diffusion coefficient based on the observed temperature profiles. The sensitivity of the inverse model in the idealized and actual conditions is tested in detail. It can be found that this inverse model has high feasibility under multiple situations ensuring the stability of the inverse model, and can be considered as an efficient way to estimate the temperature diffusion coefficient in the weak current regions of the ocean. Here, the hydrographic profiles from Argo floats are used to estimate the temporal and spatial distribution of the vertical mixing in the north central Pacific based on this inverse method. It is further found that the vertical mixing in the upper ocean displays a distinct seasonal variation with the amplitude decreasing with depth, and the vertical mixing over rough topography is stronger than that over smooth topography. It is suggested that the high-resolution profiles from Argo floats and a more reasonable design of the inverse scheme will serve to understand mixing processes.
文摘The damage of the overburden is a complex nonliear mechanical problem. To immediately master the stress state of the vertical shaft in process of the damage of overburden, and protect the shaft, in this paper, a series of new type of rock mass stress and strain compatible sensors are used. The vertical shaft wall mechanical parameter and surrounding mechanical parameter are calculated by the result of the measurement. A set of the calculation method of the vertical shaft and surrounding rock parameter are defined.
文摘A one_step smoothing Newton method is proposed for solving the vertical linear complementarity problem based on the so_called aggregation function. The proposed algorithm has the following good features: (ⅰ) It solves only one linear system of equations and does only one line search at each iteration; (ⅱ) It is well_defined for the vertical linear complementarity problem with vertical block P 0 matrix and any accumulation point of iteration sequence is its solution.Moreover, the iteration sequence is bounded for the vertical linear complementarity problem with vertical block P 0+R 0 matrix; (ⅲ) It has both global linear and local quadratic convergence without strict complementarity. Many existing smoothing Newton methods do not have the property (ⅲ).
文摘The study of wave propagation in finite/infinite media has many applications in geotechnical and structural earthquake engineering and has been a focus of research for the past few decades.This paper presents an analysis of 2D antiplane problems(Love waves)and 2D in-plane problems(Rayleigh waves)in the frequency domain in media consisting of a near-field irregular and a far-field regular part.The near field part may contain structures and its boundaries with the far-field can be of any shape.In this study,the irregular boundaries of the near-field are treated as consistent boundaries,extending the concept of Lysmer’s vertical consistent boundaries.The presented technique is called the Condensed Hyperelements Method(CHM).In this method,the irregular boundary is limited to a vertical boundary at each end that is a consistent boundary at the far-field side.Between the two ends,the medium is discretized with hyperelements.Using static condensation,the stiffness matrix of the far-field is derived for the nodes on the irregular boundary.Examples of the application of the CHM illustrate its excellent accuracy and efficiency.
基金theNaturalGasExploitationKeyLabofSichuanProvince (No .0 1 6)
文摘Based on the flow mechanism of hydraulic fractured wells, through integrating linear-flow model and effective well-radius model, a new model of well test analysis for wells with vertical fracture was established. In the model, wellbore storage, the damage in the wall of fracture and all kinds of boundary conditions are considered. The model is concise in form, has intact curves and computes fast, which may meet the demand of real-time computation and fast responded well test interpretation. A new method to determine effective well radius was presented, and the correlation between effective well radius and the fracture length, fracture conductivity, skin factor of fracture was given. Matching flow rate or pressure tested, the optimization model that identified formation and fracture parameters was set up. The automatic matching method was presented by synthetically using step by step linear least square method and sequential quadratic programming. At last, the application was also discussed. Application shows that all of these results can analyze and evaluate the fracturing treatment quality scientifically and rationally, instruct and modify the design of fracturing and improve fracturing design level.
