AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation...AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position(ELP).METHODS: Retrospective study including a total of 25 eyes of 13 patients(age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL(Oculentis Gmb H, Germany). In all cases, an adjusted IOL power(P IOLadj) was calculated based on Gaussian optics using a variable keratometric index value(n kadj) for the estimation of the corneal power(P kadj) and on a new value for ELP(ELP adj) obtained by multiple regression analysis.This P IOLadj was compared with the IOL power implanted(P IOLReal) and the value proposed by three conventional formulas(Haigis, Hoffer Q and Holladay Ⅰ).RESULTS: P IOLReal was not significantly different than P IOLadj and Holladay IOL power(P 】0.05). In the Bland and Altman analysis, P IOLadj showed lower mean difference(-0.07 D) and limits of agreement(of 1.47 and-1.61 D)when compared to P IOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELP adj was significantly lower than ELP calculated with other conventional formulas(P 【0.01) and was found to be dependent on axial length, anterior chamber depth and P kadj. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing thekeratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.展开更多
Suppose that {X(n)(omega)} are independent random complex variable sequence, E(X(n)) = 0 and [GRAPHICS] (V(X(n) = sigma(n)2). If reversed capital E-epsilon > 0 such that for all P (H) > 1-epsilon, we have [GRAPH...Suppose that {X(n)(omega)} are independent random complex variable sequence, E(X(n)) = 0 and [GRAPHICS] (V(X(n) = sigma(n)2). If reversed capital E-epsilon > 0 such that for all P (H) > 1-epsilon, we have [GRAPHICS] Then the circle {\Z\ = rho} is almost surely a natural boundary of the random series [GRAPHICS]展开更多
This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels:a smooth channel(Case 1);eight rectangular baffles were arranged in the upstream(Case 2),midstrea...This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels:a smooth channel(Case 1);eight rectangular baffles were arranged in the upstream(Case 2),midstream(Case 3),downstream(Case 4),and the entire cathode flow channel(Case 5)to study the effects of baffle position on mass transport,power density,net power,etc.Moreover,the effects of back pressure and humidity on the voltage were investigated.Results showed that compared to smooth channels,the oxygen and water transport facilitation at the diffusion layer-channel interface were added 11.53%-20.60%and 7.81%-9.80%at 1.68 A·cm^(-2)by adding baffles.The closer the baffles were to upstream,the higher the total oxygen flux,but the lower the flux uniformity the worse the water removal.The oxygen flux of upstream baffles was 8.14%higher than that of downstream baffles,but oxygen flux uniformity decreased by 18.96%at 1.68 A·cm^(-2).The order of water removal and voltage improvement was Case 4>Case 5>Case 3>Case 2>Case 1.Net power of Case 4 was 9.87%higher than that of the smooth channel.To the Case 4,when the cell worked under low back pressure or high humidity,the voltage increments were higher.The potential increment for the back pressure of 0 atm was 0.9%higher than that of 2 atm(1 atm=101.325 kPa).The potential increment for the humidity of 100%was 7.89%higher than that of 50%.展开更多
Based on the measurement of one-dimensional (1D) optical path difference (OPD) of the supersonic turbulent bound- ary layer, an analytical form for the power spectrum of the two-dimensional (2D) OPD is obtained ...Based on the measurement of one-dimensional (1D) optical path difference (OPD) of the supersonic turbulent bound- ary layer, an analytical form for the power spectrum of the two-dimensional (2D) OPD is obtained with its structure function and under the locally homogeneous isotropic assumption. The universality of this spectrum is argued, and its validity is checked by the comparison with experimental result. The potential applications of this model in theoretical and numerical studies are emphasized. Another contribution of this work is around the application of correlation function to analyzing the statistics of OPD. Based on our results and other results published elsewhere, we show that the OPD is often not stationary, and one should be cautious about using this tool.展开更多
In this study, the e?ect of the lower boundary position selection for the Fourier equation on heat transfer and energy balance in soil is evaluated. A detailed numerical study shows that the proper position of the l...In this study, the e?ect of the lower boundary position selection for the Fourier equation on heat transfer and energy balance in soil is evaluated. A detailed numerical study shows that the proper position of the lower boundary is critical when solving the Fourier equation by using zero heat ?ux as the lower boundary condition. Since the position de?nes the capacity of soil as a heat sink or source, which absorbs and stores radiation energy from the sky in summer and then releases the energy to the atmosphere in winter, and regulates the deep soil temperature distribution, the depth of the position greatly in?uences the heat balance within the soil as well as the interaction between the soil and the atmosphere. Based on physical reasoning and the results of numerical simulation, the proper depth of the position should be equal to approximately 3 times of the annual heat wave damping depth. For most soils, the proper lower boundary depth for the Fourier equation should be around 8 m to 15 m, depending on soil texture.展开更多
Using the method of lower and upper solutions, we study the following singular nonlinear three-point boundary value problems: , where K ∈ C[0,1] ,0 α η < 1 and λ is a positive parameter and present the existenc...Using the method of lower and upper solutions, we study the following singular nonlinear three-point boundary value problems: , where K ∈ C[0,1] ,0 α η < 1 and λ is a positive parameter and present the existence, uniqueness, and the dependency on parameters of the positive solutions under various assumptions. Our result improves those in the previous literatures.展开更多
This paper presents sufficient conditions for the existence of positive solutions for the fourth-order boundary value problem system with p-Laplacian operator. The existence of single or multiple positive solutions fo...This paper presents sufficient conditions for the existence of positive solutions for the fourth-order boundary value problem system with p-Laplacian operator. The existence of single or multiple positive solutions for the system is showed through the fixed point index theory in cones under some assumptions.展开更多
For any positive integer n, the famous Smarandache power function SP(n) is defined as the smallest positive integer m such that n|m^m, where m and n have the same prime divisors. The main purpose of this paper is u...For any positive integer n, the famous Smarandache power function SP(n) is defined as the smallest positive integer m such that n|m^m, where m and n have the same prime divisors. The main purpose of this paper is using the elementary methods to study the positive integer solutions of an equation involving the Smarandache power function SP(n) and obtain some interesting results. At the same time, we give an open problem about the related equation.展开更多
This article will use Foucaulfs theory to critically consider the relationship between power,people,space and society at the boundary where different powers conflict with each other.Through the analysis of the project...This article will use Foucaulfs theory to critically consider the relationship between power,people,space and society at the boundary where different powers conflict with each other.Through the analysis of the project“Decolonizing Al Nada,”this article will discuss how relations with those with power and social mentality are reframed at the border through the reconstruction of architecture and space.展开更多
An existence theorem of positive solution is established for a nonlinear third-order three-point boundary value problem. Here, we concentrated on the case that the nonlinear term is neither superlinear nor sublinear, ...An existence theorem of positive solution is established for a nonlinear third-order three-point boundary value problem. Here, we concentrated on the case that the nonlinear term is neither superlinear nor sublinear, and is not asymptotic at zero and infinity.展开更多
Finite time blow up of the solutions to Boussinesq equation with linear restoring force and combined power nonlinearities is studied. Sufficient conditions on the initial data for nonexistence of global solutions are ...Finite time blow up of the solutions to Boussinesq equation with linear restoring force and combined power nonlinearities is studied. Sufficient conditions on the initial data for nonexistence of global solutions are derived. The results are valid for initial data with arbitrary high positive energy. The proofs are based on the concave method and new sign preserving functionals.展开更多
This paper deals with the existence of positive solutions of the equation u'+f(t, u)=0 with linear boundary conditions. We show the existence of at least one positive solution if / is neither superlinear nor subli...This paper deals with the existence of positive solutions of the equation u'+f(t, u)=0 with linear boundary conditions. We show the existence of at least one positive solution if / is neither superlinear nor sublinear on u by a simple application of a fixed point Theorem in cones.展开更多
The main objective of this work is to decompose orthogonally the reproducing kernels Hilbert space using any conditionally positive definite kernels into smaller ones by introducing the theory of power kernels, and to...The main objective of this work is to decompose orthogonally the reproducing kernels Hilbert space using any conditionally positive definite kernels into smaller ones by introducing the theory of power kernels, and to show how to do this decomposition recur- sively. It may be used to split large interpolation problems into smaller ones with different kernels which are related to the original kernels. To reach this objective, we will reconstruct the reproducing kernels Hilbert space for the normalized and the extended kernels and give the recursive algorithm of this decomposition.展开更多
In this paper, the authors study the existence of positive solution of the following BVP {1/p(t)(P(t)x′)′+f(t,x(t),p(t)x′(t))=0,o〈t〈+∞ αx(0)-βlimt→0p(t)x′(t)=0,γ limt→+∞x(t)+δl...In this paper, the authors study the existence of positive solution of the following BVP {1/p(t)(P(t)x′)′+f(t,x(t),p(t)x′(t))=0,o〈t〈+∞ αx(0)-βlimt→0p(t)x′(t)=0,γ limt→+∞x(t)+δlimt→+∞p(t)x′(t)=0 on the semi-infinite interval. By considering characterization of the nonlinearity, they obtain some new existence results.展开更多
The co-variation of surface wind speed and sea surface temperature (SST) over the Gulf Stream frontal region is investigated using high-resolution satellite measurements and atmospheric reanalysis data. Results show t...The co-variation of surface wind speed and sea surface temperature (SST) over the Gulf Stream frontal region is investigated using high-resolution satellite measurements and atmospheric reanalysis data. Results show that the pattern of positive SST-surface wind speed correlations is anchored by strong SST gradient and marine atmospheric boundary layer (MABL) height front, with active warm and cold-ocean eddies around. The MABL has an obvious transitional structure along the strong SST front, with greater (lesser) heights over the north (south) side. The significant positive SST-surface wind-speed perturbation correlations are mostly found over both strong warm and cold eddies. The surface wind speed increases (decreases) about 0.32 (0.41) m/s and the MABL elevates (drops) approximate 55 (54) m per 1℃ of SST perturbation induced by warm (cold) eddies. The response of the surface wind speed to SST perturbations over the mesoscale eddies is mainly attributed to the momentum vertical mixing in the MABL, which is confirmed by the linear relationships between the downwind (crosswind) SST gradient and wind divergence (curl).展开更多
This paper presents a theoretical analysis for laminar boundary layer flow in a power law non-Newtonian fluids. The Adomian analytical decomposition technique is presented and an approximate analytical solution is obt...This paper presents a theoretical analysis for laminar boundary layer flow in a power law non-Newtonian fluids. The Adomian analytical decomposition technique is presented and an approximate analytical solution is obtained. The approximate analytical solution can be expressed in terms of a rapid convergent power series with easily computable terms. Reliability and efficiency of the approximate solution are verified by comparing with numerical solutions in the literature. Moreover, the approximate solution can be successfully applied to provide values for the skin friction coefficient of the laminar boundary layer flow in power law non-Newtonian fluids.展开更多
In this work, an enhanced treatment of the solid boundaries is proposed for smoothed particle hydrodynamics with implicit time integration scheme (Implicit SPH). Three types of virtual particles, i.e., boundary part...In this work, an enhanced treatment of the solid boundaries is proposed for smoothed particle hydrodynamics with implicit time integration scheme (Implicit SPH). Three types of virtual particles, i.e., boundary particles, image particles and mirror particles, are used to impose boundary conditions. Boundary particles are fixed on the solid boundary, and each boundary particle is associated with two fixed image particles inside the fluid domain and two fixed mirror particles outside the fluid domain. The image particles take the flow properties through fluid particles with moving least squares (MLS) interpolation and the properties of mirror particles can be obtained by the corresponding image particles. A repulsive force is also applied for boundary particles to prevent fluid particles from unphysical penetra- tion through solid boundaries. The new boundary treatment method has been validated with five numerical examples. All the numerical results show that Implicit SPH with this new boundary-treatment method can obtain accurate results for non-Newtonian fluids as well as Newtonian fluids, and this method is suitable for complex solid boundaries and can be easily extended to 3D problems.展开更多
We present a theoretic model to calculate skin depths and eddy-current power losses for a magnetic position sensor. Eddy-current, arised from the operation of an alternating-current excitation, induces secondary curre...We present a theoretic model to calculate skin depths and eddy-current power losses for a magnetic position sensor. Eddy-current, arised from the operation of an alternating-current excitation, induces secondary currents and fields between magnetic material and magnetic position sensor. In this paper, a magnetic position sensor system is simplified to be an outer-winding coil along the axial direction of a low carbon steel bar. The analytical model is derived from basic field and circuit theory considering a linear approximation for a nonlinear permeability. Thus the skin depths and eddy-current power losses from the model in eddy-current modeling techniques at various frequencies of an excited current source can be calculated. The proposed configuration is capable of predicting the skin depths and eddy-current power losses for a magnetic position sensor and has a consistence with experiments.展开更多
In this work,author expressed new R-Synthesis specifically.Good and/or correct perspective that must be behind the definitions and administration generally expressed.New perspective of the philosophy explained general...In this work,author expressed new R-Synthesis specifically.Good and/or correct perspective that must be behind the definitions and administration generally expressed.New perspective of the philosophy explained generally.Philosophy of GodForm is defined and expressed as connected/related with the following concepts:(a)basic principles,(b)17 upper constructional philosophies,(c)14 lower constructional philosophies,(d)eight basic philosophies.As special cases,Philosophy of Engineering and Technology,Philosophy of Wireless Administration and others defined as hybrid philosophies.17 specific components/units which can be considered to define the basic principles of the related formation,are proposed to be designed by GodForm and defined by the author.Philosophy of GodForm and its relation with Values and Positions specifically defined.New Era Theory and New Era Belief explained generally.Some specific religions/beliefs are defined as variants/forms of the Progressive Religion.Good and/or correct power authorities(R-Power Authority)are defined due to 29 categories.Functional position levels defined for the R-Power Authorities with a unique table.As result of the R-Synthesis,functional position levels of some philosophers,some scientists,and of Prophet Jesus,Prophet Mohamed,Prophets Mouses,Buddha,and of Confucius generally/specifically defined.Integration and past/present effects of some R-Power Authorities in 5 x 5 Ideal Political Construction specifically explained.New Era Belief,Concepts of GodX and Science relation explained with the following concepts:(1)Religion of GodForm,(2)Knowledge of GodX,(3)Nature of GodX.With this respect,some other characteristics of 7 GodX power authorities expressed with details as complementary information.Following concepts/systems defined to arrange and solve some/most/all religious problems,which are determined with R-Synthesis:(a)Religious Responsibilities and Positions,(b)Ideal Religious Administration,(c)Sustainable/Continuable Political Administration System,(d)Community Values Council/Authority for each world country,(e)Progressive Councils.15 general religious position categories defined to express their good and/or correct meanings/values/responsibilities in the religious system.21 general/specific cases/programs defined due to New Era Belief to solve possible past/present/future community values problems,to have continuous,judicious,and progressive administration about the 36 kinds of community values.Progressive Councils,which are related with the CUS-WW-HO,are defined.Progressive Religion Council and some of the related religious responsibilities expressed for the kind progressive religion studies due to the Philosophy of Progressive Religions.展开更多
Although the parallel mechanisms have the advantages of high accuracy, velocity, stiffness, and payload capacity, the shortcomings of the space utilization and workspace limit the applications in the confined space. A...Although the parallel mechanisms have the advantages of high accuracy, velocity, stiffness, and payload capacity, the shortcomings of the space utilization and workspace limit the applications in the confined space. A novel 3 degrees of freedom spatial parallel manipulator 3-PSR-O(prismatic-spherical-revolute) is proposed, which possesses a compact architecture and extended workspace while maintaining the inherent advantages of the parallel mechanisms. The direct-inverse position, singularity and workspace are investigated. The mapping method is adopted in the position analysis, and the closed form solution is derived in the form of a six order equation. The singularity analysis of the mechanism is also carried out based on the geometrical constraints, including six singularity boundaries. A feature boundary, which is independent of the prismatic joints' stroke limit, is obtained by integrating the six singularity boundaries. According to the formation of the reachable workspace, a concept of basic workspace is also introduced and presented in the analytical way. By demarcating the basic workspace along the central height with the feature boundary, the reachable workspace can be derived and analyzed more efficiently. Finally, a comparative study on the space utilization between the 3-PSP parallel mechanism and the new mechanism is also presented. The area of feature boundary of the new mechanism is about 140% of the 3-PSP parallel mechanism, while its installation radius is only 1/2 of the 3-PSP parallel mechanism. The proposed parallel mechanism shows great space utilization, and is ideally suited for applications in confined space occasions such as immersion lithography, nano-imprint etc.展开更多
文摘AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position(ELP).METHODS: Retrospective study including a total of 25 eyes of 13 patients(age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL(Oculentis Gmb H, Germany). In all cases, an adjusted IOL power(P IOLadj) was calculated based on Gaussian optics using a variable keratometric index value(n kadj) for the estimation of the corneal power(P kadj) and on a new value for ELP(ELP adj) obtained by multiple regression analysis.This P IOLadj was compared with the IOL power implanted(P IOLReal) and the value proposed by three conventional formulas(Haigis, Hoffer Q and Holladay Ⅰ).RESULTS: P IOLReal was not significantly different than P IOLadj and Holladay IOL power(P 】0.05). In the Bland and Altman analysis, P IOLadj showed lower mean difference(-0.07 D) and limits of agreement(of 1.47 and-1.61 D)when compared to P IOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELP adj was significantly lower than ELP calculated with other conventional formulas(P 【0.01) and was found to be dependent on axial length, anterior chamber depth and P kadj. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing thekeratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.
文摘Suppose that {X(n)(omega)} are independent random complex variable sequence, E(X(n)) = 0 and [GRAPHICS] (V(X(n) = sigma(n)2). If reversed capital E-epsilon > 0 such that for all P (H) > 1-epsilon, we have [GRAPHICS] Then the circle {\Z\ = rho} is almost surely a natural boundary of the random series [GRAPHICS]
基金financially supported by the Science&Technology Project of Beijing Education Committee(KM202210005013)National Natural Science Foundation of China(52306180)。
文摘This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels:a smooth channel(Case 1);eight rectangular baffles were arranged in the upstream(Case 2),midstream(Case 3),downstream(Case 4),and the entire cathode flow channel(Case 5)to study the effects of baffle position on mass transport,power density,net power,etc.Moreover,the effects of back pressure and humidity on the voltage were investigated.Results showed that compared to smooth channels,the oxygen and water transport facilitation at the diffusion layer-channel interface were added 11.53%-20.60%and 7.81%-9.80%at 1.68 A·cm^(-2)by adding baffles.The closer the baffles were to upstream,the higher the total oxygen flux,but the lower the flux uniformity the worse the water removal.The oxygen flux of upstream baffles was 8.14%higher than that of downstream baffles,but oxygen flux uniformity decreased by 18.96%at 1.68 A·cm^(-2).The order of water removal and voltage improvement was Case 4>Case 5>Case 3>Case 2>Case 1.Net power of Case 4 was 9.87%higher than that of the smooth channel.To the Case 4,when the cell worked under low back pressure or high humidity,the voltage increments were higher.The potential increment for the back pressure of 0 atm was 0.9%higher than that of 2 atm(1 atm=101.325 kPa).The potential increment for the humidity of 100%was 7.89%higher than that of 50%.
基金Project supported by the National Natural Science Foundation of China(Grant No.61008037)the National Basic Research Program of China(Grant No.2009CB724100)
文摘Based on the measurement of one-dimensional (1D) optical path difference (OPD) of the supersonic turbulent bound- ary layer, an analytical form for the power spectrum of the two-dimensional (2D) OPD is obtained with its structure function and under the locally homogeneous isotropic assumption. The universality of this spectrum is argued, and its validity is checked by the comparison with experimental result. The potential applications of this model in theoretical and numerical studies are emphasized. Another contribution of this work is around the application of correlation function to analyzing the statistics of OPD. Based on our results and other results published elsewhere, we show that the OPD is often not stationary, and one should be cautious about using this tool.
基金National Natural Science Founda-tion of China under Grant Nos.40233034 , 40075019KZCX2-SW-210National Natural Science Foun-dation of China under Grant No.40305011.
文摘In this study, the e?ect of the lower boundary position selection for the Fourier equation on heat transfer and energy balance in soil is evaluated. A detailed numerical study shows that the proper position of the lower boundary is critical when solving the Fourier equation by using zero heat ?ux as the lower boundary condition. Since the position de?nes the capacity of soil as a heat sink or source, which absorbs and stores radiation energy from the sky in summer and then releases the energy to the atmosphere in winter, and regulates the deep soil temperature distribution, the depth of the position greatly in?uences the heat balance within the soil as well as the interaction between the soil and the atmosphere. Based on physical reasoning and the results of numerical simulation, the proper depth of the position should be equal to approximately 3 times of the annual heat wave damping depth. For most soils, the proper lower boundary depth for the Fourier equation should be around 8 m to 15 m, depending on soil texture.
文摘Using the method of lower and upper solutions, we study the following singular nonlinear three-point boundary value problems: , where K ∈ C[0,1] ,0 α η < 1 and λ is a positive parameter and present the existence, uniqueness, and the dependency on parameters of the positive solutions under various assumptions. Our result improves those in the previous literatures.
文摘This paper presents sufficient conditions for the existence of positive solutions for the fourth-order boundary value problem system with p-Laplacian operator. The existence of single or multiple positive solutions for the system is showed through the fixed point index theory in cones under some assumptions.
基金Supported by the Natural Science Foundation of China(10671155)
文摘For any positive integer n, the famous Smarandache power function SP(n) is defined as the smallest positive integer m such that n|m^m, where m and n have the same prime divisors. The main purpose of this paper is using the elementary methods to study the positive integer solutions of an equation involving the Smarandache power function SP(n) and obtain some interesting results. At the same time, we give an open problem about the related equation.
文摘This article will use Foucaulfs theory to critically consider the relationship between power,people,space and society at the boundary where different powers conflict with each other.Through the analysis of the project“Decolonizing Al Nada,”this article will discuss how relations with those with power and social mentality are reframed at the border through the reconstruction of architecture and space.
文摘An existence theorem of positive solution is established for a nonlinear third-order three-point boundary value problem. Here, we concentrated on the case that the nonlinear term is neither superlinear nor sublinear, and is not asymptotic at zero and infinity.
基金partially supported by Grant No.DFNI I-02/9 of the Bulgarian Science Fund
文摘Finite time blow up of the solutions to Boussinesq equation with linear restoring force and combined power nonlinearities is studied. Sufficient conditions on the initial data for nonexistence of global solutions are derived. The results are valid for initial data with arbitrary high positive energy. The proofs are based on the concave method and new sign preserving functionals.
文摘This paper deals with the existence of positive solutions of the equation u'+f(t, u)=0 with linear boundary conditions. We show the existence of at least one positive solution if / is neither superlinear nor sublinear on u by a simple application of a fixed point Theorem in cones.
文摘The main objective of this work is to decompose orthogonally the reproducing kernels Hilbert space using any conditionally positive definite kernels into smaller ones by introducing the theory of power kernels, and to show how to do this decomposition recur- sively. It may be used to split large interpolation problems into smaller ones with different kernels which are related to the original kernels. To reach this objective, we will reconstruct the reproducing kernels Hilbert space for the normalized and the extended kernels and give the recursive algorithm of this decomposition.
基金Supported by the Natural Scientific Fund of Zhejiang Province(Y604127)Supported by the Educational Scientific Fund of Zhejiang Province(20030594)
文摘In this paper, the authors study the existence of positive solution of the following BVP {1/p(t)(P(t)x′)′+f(t,x(t),p(t)x′(t))=0,o〈t〈+∞ αx(0)-βlimt→0p(t)x′(t)=0,γ limt→+∞x(t)+δlimt→+∞p(t)x′(t)=0 on the semi-infinite interval. By considering characterization of the nonlinearity, they obtain some new existence results.
基金Supported by the China’s National Key Research and Development Projects(No.2016YFA0601803)the National Natural Science Foundation of China(Nos.41490641,41521091,U1606402)the Qingdao National Laboratory for Marine Science and Technology(No.2017ASKJ01)
文摘The co-variation of surface wind speed and sea surface temperature (SST) over the Gulf Stream frontal region is investigated using high-resolution satellite measurements and atmospheric reanalysis data. Results show that the pattern of positive SST-surface wind speed correlations is anchored by strong SST gradient and marine atmospheric boundary layer (MABL) height front, with active warm and cold-ocean eddies around. The MABL has an obvious transitional structure along the strong SST front, with greater (lesser) heights over the north (south) side. The significant positive SST-surface wind-speed perturbation correlations are mostly found over both strong warm and cold eddies. The surface wind speed increases (decreases) about 0.32 (0.41) m/s and the MABL elevates (drops) approximate 55 (54) m per 1℃ of SST perturbation induced by warm (cold) eddies. The response of the surface wind speed to SST perturbations over the mesoscale eddies is mainly attributed to the momentum vertical mixing in the MABL, which is confirmed by the linear relationships between the downwind (crosswind) SST gradient and wind divergence (curl).
基金the Science Foundation of North China Electric Power University(No.93210706)
文摘This paper presents a theoretical analysis for laminar boundary layer flow in a power law non-Newtonian fluids. The Adomian analytical decomposition technique is presented and an approximate analytical solution is obtained. The approximate analytical solution can be expressed in terms of a rapid convergent power series with easily computable terms. Reliability and efficiency of the approximate solution are verified by comparing with numerical solutions in the literature. Moreover, the approximate solution can be successfully applied to provide values for the skin friction coefficient of the laminar boundary layer flow in power law non-Newtonian fluids.
基金supported by the National Natural Science Foundation of China(51276192)
文摘In this work, an enhanced treatment of the solid boundaries is proposed for smoothed particle hydrodynamics with implicit time integration scheme (Implicit SPH). Three types of virtual particles, i.e., boundary particles, image particles and mirror particles, are used to impose boundary conditions. Boundary particles are fixed on the solid boundary, and each boundary particle is associated with two fixed image particles inside the fluid domain and two fixed mirror particles outside the fluid domain. The image particles take the flow properties through fluid particles with moving least squares (MLS) interpolation and the properties of mirror particles can be obtained by the corresponding image particles. A repulsive force is also applied for boundary particles to prevent fluid particles from unphysical penetra- tion through solid boundaries. The new boundary treatment method has been validated with five numerical examples. All the numerical results show that Implicit SPH with this new boundary-treatment method can obtain accurate results for non-Newtonian fluids as well as Newtonian fluids, and this method is suitable for complex solid boundaries and can be easily extended to 3D problems.
文摘We present a theoretic model to calculate skin depths and eddy-current power losses for a magnetic position sensor. Eddy-current, arised from the operation of an alternating-current excitation, induces secondary currents and fields between magnetic material and magnetic position sensor. In this paper, a magnetic position sensor system is simplified to be an outer-winding coil along the axial direction of a low carbon steel bar. The analytical model is derived from basic field and circuit theory considering a linear approximation for a nonlinear permeability. Thus the skin depths and eddy-current power losses from the model in eddy-current modeling techniques at various frequencies of an excited current source can be calculated. The proposed configuration is capable of predicting the skin depths and eddy-current power losses for a magnetic position sensor and has a consistence with experiments.
文摘In this work,author expressed new R-Synthesis specifically.Good and/or correct perspective that must be behind the definitions and administration generally expressed.New perspective of the philosophy explained generally.Philosophy of GodForm is defined and expressed as connected/related with the following concepts:(a)basic principles,(b)17 upper constructional philosophies,(c)14 lower constructional philosophies,(d)eight basic philosophies.As special cases,Philosophy of Engineering and Technology,Philosophy of Wireless Administration and others defined as hybrid philosophies.17 specific components/units which can be considered to define the basic principles of the related formation,are proposed to be designed by GodForm and defined by the author.Philosophy of GodForm and its relation with Values and Positions specifically defined.New Era Theory and New Era Belief explained generally.Some specific religions/beliefs are defined as variants/forms of the Progressive Religion.Good and/or correct power authorities(R-Power Authority)are defined due to 29 categories.Functional position levels defined for the R-Power Authorities with a unique table.As result of the R-Synthesis,functional position levels of some philosophers,some scientists,and of Prophet Jesus,Prophet Mohamed,Prophets Mouses,Buddha,and of Confucius generally/specifically defined.Integration and past/present effects of some R-Power Authorities in 5 x 5 Ideal Political Construction specifically explained.New Era Belief,Concepts of GodX and Science relation explained with the following concepts:(1)Religion of GodForm,(2)Knowledge of GodX,(3)Nature of GodX.With this respect,some other characteristics of 7 GodX power authorities expressed with details as complementary information.Following concepts/systems defined to arrange and solve some/most/all religious problems,which are determined with R-Synthesis:(a)Religious Responsibilities and Positions,(b)Ideal Religious Administration,(c)Sustainable/Continuable Political Administration System,(d)Community Values Council/Authority for each world country,(e)Progressive Councils.15 general religious position categories defined to express their good and/or correct meanings/values/responsibilities in the religious system.21 general/specific cases/programs defined due to New Era Belief to solve possible past/present/future community values problems,to have continuous,judicious,and progressive administration about the 36 kinds of community values.Progressive Councils,which are related with the CUS-WW-HO,are defined.Progressive Religion Council and some of the related religious responsibilities expressed for the kind progressive religion studies due to the Philosophy of Progressive Religions.
基金Supported by National Natural Science Foundation of China(Grant No.51221004)National Hi-tech Research and Development Program of China(863 Program,Grant No.2012AA040605)
文摘Although the parallel mechanisms have the advantages of high accuracy, velocity, stiffness, and payload capacity, the shortcomings of the space utilization and workspace limit the applications in the confined space. A novel 3 degrees of freedom spatial parallel manipulator 3-PSR-O(prismatic-spherical-revolute) is proposed, which possesses a compact architecture and extended workspace while maintaining the inherent advantages of the parallel mechanisms. The direct-inverse position, singularity and workspace are investigated. The mapping method is adopted in the position analysis, and the closed form solution is derived in the form of a six order equation. The singularity analysis of the mechanism is also carried out based on the geometrical constraints, including six singularity boundaries. A feature boundary, which is independent of the prismatic joints' stroke limit, is obtained by integrating the six singularity boundaries. According to the formation of the reachable workspace, a concept of basic workspace is also introduced and presented in the analytical way. By demarcating the basic workspace along the central height with the feature boundary, the reachable workspace can be derived and analyzed more efficiently. Finally, a comparative study on the space utilization between the 3-PSP parallel mechanism and the new mechanism is also presented. The area of feature boundary of the new mechanism is about 140% of the 3-PSP parallel mechanism, while its installation radius is only 1/2 of the 3-PSP parallel mechanism. The proposed parallel mechanism shows great space utilization, and is ideally suited for applications in confined space occasions such as immersion lithography, nano-imprint etc.