All-polymer solar cells(all-PSCs)possess attractive merits including superior thermal stability and mechanical flexibility for large-area roll-to-roll processing.Introducing flexible conjugation-break spacers(FCBSs)in...All-polymer solar cells(all-PSCs)possess attractive merits including superior thermal stability and mechanical flexibility for large-area roll-to-roll processing.Introducing flexible conjugation-break spacers(FCBSs)into backbones of polymer donor(P_(D))or polymer acceptor(P_(A))has been demonstrated as an efficient approach to enhance both the photovoltaic(PV)and mechanical properties of the all-PSCs.However,length dependency of FCBS on certain all-PSC related properties has not been systematically explored.In this regard,we report a series of new non-conjugated P_(A)s by incorporating FCBS with various lengths(2,4,and 8 carbon atoms in thioalkyl segments).Unlike com-mon studies on so-called side-chain engineering,where longer side chains would lead to better solubility of those resulting polymers,in this work,we observe that the solubilities and the resulting photovoltaic/mechanical properties are optimized by a proper FCBS length(i.e.,C2)in P_(A) named PYTS-C2.Its all-PSC achieves a high efficiency of 11.37%,and excellent mechanical robustness with a crack onset strain of 12.39%,significantly superior to those of the other P_(A)s.These results firstly demonstrate the effects of FCBS lengths on the PV performance and mechanical properties of the all-PSCs,providing an effective strategy to fine-tune the structures of P_(A)s for highly efficient and mechanically robust PSCs.展开更多
Metastasis to distant sites is a severe treatment challenge and a major cause of death for breast cancer patients.Laser immunotherapy(LIT)is a novel technique,combining a selective photothermal therapy with local appl...Metastasis to distant sites is a severe treatment challenge and a major cause of death for breast cancer patients.Laser immunotherapy(LIT)is a novel technique,combining a selective photothermal therapy with local application of glycated chitosan,a potent immunoadjuvant.The pre-clinical studies of LIT have shown its unique characteristics in generating specific antitumor immunity.The clinical application of LIT in the treatment of melanoma patients has achieved preliminary success.Recently,LIT has been used to treat late-stage breast cancer patients.Here we report for the first time the clinical results of this combination therapy in breast cancer patients.The LIT treatment procedures are presented and the medical history of two stage Ⅳ breast cancer patients is reviewed.Most of the breast cancer lesions and the metastasis of lung and brain disappeared after repeated treatments of LIT.One patient achieved complete response;the other achieved partial response at the time of this report.Although there is still a long way for LIT to become a standard modality for breast cancer treatment,the results of this study indicated its promising future.展开更多
The purpose of this paper is to propose a new multi stage algorithm for the recognition of isolated characters. It was similar work done before using only the center of gravity (This paper is extended version of “A f...The purpose of this paper is to propose a new multi stage algorithm for the recognition of isolated characters. It was similar work done before using only the center of gravity (This paper is extended version of “A fast recognition system for isolated printed characters using center of gravity”, LAP LAMBERT Academic Publishing 2011, ISBN: 978-38465-0002-6), but here we add using principal axis in order to make the algorithm rotation invariant. In my previous work which is published in LAP LAMBERT, I face a big problem that when the character is rotated I can’t recognize the character. So this adds constrain on the document to be well oriented but here I use the principal axis in order to unify the orientation of the character set and the characters in the scanned document. The algorithm can be applied for any isolated character such as Latin, Chinese, Japanese, and Arabic characters but it has been applied in this paper for Arabic characters. The approach uses normalized and isolated characters of the same size and extracts an image signature based on the center of gravity of the character after making the character principal axis vertical, and then the system compares these values to a set of signatures for typical characters of the set. The system then provides the closeness of match to all other characters in the set.展开更多
In this paper, two different numerical schemes, namely the Runge-Kutta fourth order method and the implicit Euler method with perturbation method of the second degree, are applied to solve the nonlinear thermal wave i...In this paper, two different numerical schemes, namely the Runge-Kutta fourth order method and the implicit Euler method with perturbation method of the second degree, are applied to solve the nonlinear thermal wave in one and two dimensions using the differential quadrature method. The aim of this paper is to make comparison between previous numerical schemes and detect which is more efficient and more accurate by comparing the obtained results with the available analytical ones and computing the computational time.展开更多
Block braked railway wheels are subjected to thermal and rolling contact loading.The thermal loading results in high temperatures and thermal stresses which cause slow time dependent processes such as creep,relaxation...Block braked railway wheels are subjected to thermal and rolling contact loading.The thermal loading results in high temperatures and thermal stresses which cause slow time dependent processes such as creep,relaxation and static recovery of the wheel material.At the same time,the rolling contact loading implies a very fast mechanical load application.This paper is focused on material modeling of pearlitic steel for a wide range of loading rates at elevated temperatures.The starting point is a viscoplasticity model including nonlinear isotropic and kinematic hardening.The Delobelle overstress function is employed to capture strain rate dependent response of the material.The model also includes static recovery of the hardening to capture slower viscous(diffusion dominated)behaviour of the material.Experiments for the pearlitic wheel steel ER7 in terms of cyclic strain-controlled uniaxial tests with hold-time,uniaxial ratchetting tests including rapid cycles and biaxial cyclic tests with tension/compression and torsion are used to calibrate the material model.These experiments were performed under isothermal conditions at different temperatures.In the ratchetting tests,higher loading rates are obtained and these have been used to calibrate the high strain rate response of the viscoplasticity model.The paper is concluded with a numerical example of a block braked wheel where the importance of accounting for the viscoplasticity in modelling is highlighted.展开更多
Four numerical schemes are introduced for the analysis of photocurrent transients in organic photovoltaic devices.Themathematicalmodel for organic polymer solar cells contains a nonlinear diffusion-reaction partial di...Four numerical schemes are introduced for the analysis of photocurrent transients in organic photovoltaic devices.Themathematicalmodel for organic polymer solar cells contains a nonlinear diffusion-reaction partial differential equation system with electrostatic convection attached to a kinetic ordinary differential equation.To solve the problem,Polynomial-based differential quadrature,Sinc,and Discrete singular convolution are combined with block marching techniques.These schemes are employed to reduce the problem to a nonlinear algebraic system.The iterative quadrature technique is used to solve the reduced problem.The obtained results agreed with the previous exact one and the finite element method.Further,the effects of different times,different mobilities,different densities,different geminate pair distances,different geminate recombination rate constants,different generation efficiencies,and supporting conditions on photocurrent have been analyzed.The novelty of this paper is that these schemes for photocurrent transients in organic polymer solar cells have never been presented before,so the results may be useful for improving the performance of solar cells.展开更多
The processes of tsunami evolution during its generation in search for possible amplification mechanisms resulting from unilateral spreading of the sea floor uplift is investigated. We study the nature of the tsunami ...The processes of tsunami evolution during its generation in search for possible amplification mechanisms resulting from unilateral spreading of the sea floor uplift is investigated. We study the nature of the tsunami build up and propagation during and after realistic curvilinear source models represented by a slowly uplift faulting and a spreading slip-fault model. The models are used to study the tsunami amplitude amplification as a function of the spreading velocity and rise time. Tsunami waveforms within the frame of the linearized shallow water theory for constant water depth are analyzed analytically by transform methods (Laplace in time and Fourier in space) for the movable source models. We analyzed the normalized peak amplitude as a function of the propagated uplift length, width and the average depth of the ocean along the propagation path.展开更多
Bis[1-methoxy-2,2,2-tris-(pyrazol-l-yl-KN2)ethane]-copper(Ⅱ) bis-perchlorate (2) was synthesized by reacting of pyrazole based tripodal scorpionate ligand 1-methoxy-2,2,2-tris(pyrazol-1-yl)ethane (1) with c...Bis[1-methoxy-2,2,2-tris-(pyrazol-l-yl-KN2)ethane]-copper(Ⅱ) bis-perchlorate (2) was synthesized by reacting of pyrazole based tripodal scorpionate ligand 1-methoxy-2,2,2-tris(pyrazol-1-yl)ethane (1) with copper(Ⅱ) perchlorate hexahydrate in methanol, acetonitrile and water mixture as solvent. Slow evaporation of the filtered reaction mixture in air produced blue color block crystals suitable for single crystal X-ray diffraction study of the title complex. Compound 2 crystallizes in the monoclinic space group P21/n with unit cell parameters, α = 8.1269(1) ,A, b = 21.8348(2)A, c = 9.1522(1) A, a = γ= 90° , β = 99.7611 (4)°. The structure of the compound was characterized by IR Spectroscopy, elemental analysis and single crystal X-ray diffraction analysis.展开更多
The paper investigates the numerical solution of the magnetohydrodynamics (MHD) boundary layer flow of non-Newtonian Casson fluid on a moving wedge with heat and mass transfer. The effects of thermal diffusion and dif...The paper investigates the numerical solution of the magnetohydrodynamics (MHD) boundary layer flow of non-Newtonian Casson fluid on a moving wedge with heat and mass transfer. The effects of thermal diffusion and diffusion thermo with induced magnetic field are taken in consideration. The governing partial differential equations are transformed into nonlinear ordinary differential equations by applying the similarity transformation and solved numerically by using finite difference method (FDM). The effects of various governing parameters, on the velocity, temperature and concentration are displayed through graphs and discussed numerically. In order to verify the accuracy of the present results, we have compared these results with the analytical solutions by using the differential transform method (DTM). It is observed that this approximate numerical solution is in good agreement with the analytical solution. Furthermore, comparisons of the present results with previously published work show that the present results have high accuracy.展开更多
The paper investigates the numerical solution of problem of magnetohydrodynamic (MHD) micropolar fluid flow with heat and mass transfer towards a stagnation point on a vertical plate. In this study, we consider both s...The paper investigates the numerical solution of problem of magnetohydrodynamic (MHD) micropolar fluid flow with heat and mass transfer towards a stagnation point on a vertical plate. In this study, we consider both strong concentrations (n = 0) and weak concentrations (n = 1/2). The governing equations have been transformed into nonlinear ordinary differential equations by applying the similarity transformation and have been solved numerically by using the finite difference method (FDM) and analytically by using (DTM). The effects of various governing parameters, namely, material parameter, radiation parameter, magnetic parameter, Prandtl number, Schmidt number, chemical reaction parameter and Soret number on the velocity, microrotation, temperature and concentration have been computed and discussed in detail through some figures and tables. In order to verify the accuracy of the present results, we have compared these results with the analytical solutions by using the differential transform method (DTM) and the multi-step differential transform method (MDTM). It is observed that this approximate numerical solution is in good agreement with the analytical solution.展开更多
We deal with the Wick-type stochastic fractional Korteweg de–Vries(KdV) equation with conformable derivatives.With the aid of the Exp-function method, white noise theory, and Hermite transform, we produce a novel set...We deal with the Wick-type stochastic fractional Korteweg de–Vries(KdV) equation with conformable derivatives.With the aid of the Exp-function method, white noise theory, and Hermite transform, we produce a novel set of exact soliton and periodic wave solutions to the fractional KdV equation with conformable derivatives. With the help of inverse Hermite transform, we get stochastic soliton and periodic wave solutions of the Wick-type stochastic fractional KdV equation with conformable derivatives. Eventually, by an application example, we show how the stochastic solutions can be given as Brownian motion functional solutions.展开更多
This study examines the hydrodynamic performance of multiple-row vertical slotted breakwaters. We developed a mathematical model based on an eigenfunction expansion method and a least squares technique for Stokes seco...This study examines the hydrodynamic performance of multiple-row vertical slotted breakwaters. We developed a mathematical model based on an eigenfunction expansion method and a least squares technique for Stokes second-order waves. The numerical results obtained for limiting cases of double-row and triple-row walls are in good agreement with results of previous studies and experimental results. Comparisons with experimental measurements of the reflection, transmission, and dissipation coefficients (CR, Cr, and CE) for double-row walls show that the proposed mathematical model adequately reproduces most of the important features. We found that for double-row walls, the CR increases with increasing wave number, kd, and with a decreasing permeable wall part, din. The Cr follows the opposite trend. The CE slowly increases with an increasing kd for lower kd values, reaches a maximum, and then decreases again. In addition, an increasing porosity of dm would significantly decrease the CR while increasing the Cr. At lower values of kd, a decreasing porosity increases the CE, but for high values of kd, a decreasing porosity reduces the Ce. The numerical results indicate that, for triple-row walls, the effect of the arrangement of the chamber widths on hydrodynamic characteristics is not significant, except when kd〈0.5 Double-row slotted breakwaters may exhibit a good wave-absorbing performance at kd〉0.5, where by the horizontal wave force may be smaller than that of a single wall. On the other hand, the difference between double-row and triple-row vertical slotted breakwaters is marginal.展开更多
Anti-tunor immunological response induced by local intervention is ideal for treatment of metastatic tumors.Laser immunot herapy was developed to synergize photot hermal interaction with immunological stimulation for ...Anti-tunor immunological response induced by local intervention is ideal for treatment of metastatic tumors.Laser immunot herapy was developed to synergize photot hermal interaction with immunological stimulation for cancer treatment.Using an infrared laser,indocyanine green(ICG,as a light abeorbing agent),and glycated chitosan(GC,as an immunostimulant),.laser imm unot herapy has resulted in tumor suppression and anti-tumor responses in pre-clinical as well as clinical studies.To further understand the mechanism of laser immunotherapy,the efects of laser and GC treatment without specifc enhancement of laser absorption were studied.Passive adoptive immunity transfer was perfomed using splenocytes as immune cells.Spleen cells harvested from tumor-bearing mice treated by laser+GC provided 60%immunity in naive recipients.Furthermore,cytotoxicity and TNF-ar secretion by splenocytes from treated mice also indicated that laser+GC induced immunity was tumor-specific.The high level of infiltrating T cells in tumors after laser+GC treatment furt her confirned a specific anti-tumor immune response.Therefore,laser+GC could prove to be a promisi ng selective local trea tment modality that induces a systemic anti-tumor response,with appropriate laser parameters and GC doses.展开更多
The peristaltic pumping of a viscous compressible liquid mixed with rigid spherical particles of the same size in a channel is theoretically investigated. The momentum equations for the compressible flow are solved wi...The peristaltic pumping of a viscous compressible liquid mixed with rigid spherical particles of the same size in a channel is theoretically investigated. The momentum equations for the compressible flow are solved with a perturbation analysis. The analysis is carried out by duly accounting for the nonlinear convective acceleration terms for the fluid part on the wavy wall. The zeroth-order terms yield the Poiseuille flow, and the first-order terms give the Orr-Sommerfeld equation. The explicit expression for the net axial velocity is derived. The effects of the embedded parameters on the axial fluid velocity are studied through different engineering applications. The features of the flow characteristics are analyzed and discussed in detail. The obtained results are evaluated for various parameters associated with the blood flow in the blood vessels with diameters less than 5 500 μm, whereas the particle diameter has been taken to be 8 μm. This study provides a scope to evaluate the effect of the theory of two-phase flow characteristics with compressible fluid problems, and is helpful for understanding the role of engineering applications of pumping solid-fluid mixture by peristaltically driven motion.展开更多
The present work is concerned with the problem of mode Ⅲ crack perpendicular to the interface of a bi-strip composite. One of these strips is made of a functionally graded material and the other of an isotropic mater...The present work is concerned with the problem of mode Ⅲ crack perpendicular to the interface of a bi-strip composite. One of these strips is made of a functionally graded material and the other of an isotropic material, which contains an edge crack perpendicular to and terminating at the interface. Fourier transforms and asymptotic analysis are employed to reduce the problem to a singular integral equation which is numerically solved using Gauss-Chebyshev quadrature formulae. Furthermore, a parametric study is carried out to investigate the effects of elastic and geometric characteristics of the composite on the values of stress intensity factor.展开更多
Apoptosis is an important cellular event that plays a key role in the therapy of many diseases.The mechanism of the initiation and regulation of photodynamic therapy(PDT)–induced apoptosis is complex.Our previous stu...Apoptosis is an important cellular event that plays a key role in the therapy of many diseases.The mechanism of the initiation and regulation of photodynamic therapy(PDT)–induced apoptosis is complex.Our previous study found that Photofrin was localized primarily in mitochondria,the primary targets of Photofrin-PDT.The key role of Bax in the mitochondria-mediated apoptosis has been demonstrated in many systems.In order to determine the role of Bax in the mitochondrion-mediated apoptosis induced by Photofrin-PDT,we used the GFP-Bax plasmid to monitor the dynamics of Bax activation after PDT treatment.With laser scanning confocal microscopy,we found that Bax did not translocate from the cytosol to mitochondria when the mitochondrial membrane potential(∆Ψm)disappeared,measured by TMRM.Thus,for Photofrin-PDT,the commitment to cell death is independent of Bax activation.展开更多
Microglial activation plays an important role in neurodegenerative diseases.Once activated,they have macrophage-like capabilities,which can be beneficial by phagocytosis and harmful by se-cretion of neurotoxins.Howeve...Microglial activation plays an important role in neurodegenerative diseases.Once activated,they have macrophage-like capabilities,which can be beneficial by phagocytosis and harmful by se-cretion of neurotoxins.However,the resident microglia always fail to trigger an effective pha-gocytic response to clear dead cells or Aβdeposits during the progression of neurodegeneration.Therefore,the regulation of microglial phagocytosis is considered a useful strategy in searchingfor neuroprotective treatments.In this study,our results showed that low-power laser iradiation(LPLI)(20 J/cm²)could enhance microglial phagocytic function in LPS-activated microglia.Wefound that LPLI-mediated microglial phagocytosis is a Rac-1-dependent actin-based process,that a constitutively activated form of Rac1(RaclQ61L)induced a higher level of actin pol-ymerization than cells transfected with wild-type Racl,whereas a dominant negative form ofRacl(RaclT17N)markedly suppressed actin polymerization.In addition,the involvement of Racl activation after LPLI treatment was also observed by using a Raichu fluorescence resonance energy transfer(FRET)-based biosensor.We also found that PI3K/Akt pathway was required inthe LPLI-induced Raci activation.Our research may provide a feasible therapeutic approach tocontrol the progression of neurodegenerative diseases.展开更多
In this paper,the non-stationary incompressible fluid flows governed by the Navier-Stokes equations are studied in a bounded domain.This study focuses on the time-fractional Navier-Stokes equations in the optimal cont...In this paper,the non-stationary incompressible fluid flows governed by the Navier-Stokes equations are studied in a bounded domain.This study focuses on the time-fractional Navier-Stokes equations in the optimal control subject,where the control is distributed within the domain and the time-fractional derivative is proposed as Riemann-Liouville sort.In addition,the control object is to minimize the quadratic cost functional.By using the Lax-Milgram lemma with the assistance of the fixed-point theorem,we demonstrate the existence and uniqueness of the weak solution to this system.Moreover,for a quadratic cost functional subject to the time-fractional Navier-Stokes equations,we prove the existence and uniqueness of optimal control.Also,via the variational inequality upon introducing the adjoint linearized system,some inequalities and identities are given to guarantee the first-order necessary optimality conditions.A direct consequence of the results obtained here is that when a→1,the obtained results are valid for the classical optimal control of systems governed by the Navier-Stokes equations.展开更多
Reflection characteristics of longitudinal strain waves in a semi-infinite elastic rod con- nected to a viscoelastic stratum are investigated analytically.The three-dimensional viscoelasticity the- ory is applied to t...Reflection characteristics of longitudinal strain waves in a semi-infinite elastic rod con- nected to a viscoelastic stratum are investigated analytically.The three-dimensional viscoelasticity the- ory is applied to the stratum,and the Laplace transform with respect to time and the numerical inverse Laplace transform by means of Laguerre function are used.The time histories for the longitudinal strain of an arbitrary point of the rod are presented.Two typical viscoelastic models are considered, one is the usual Maxwell-Voigt model,the other is whose relaxation function is given by a power law. The numerical results for the two models are presented and compared each other and also with previ- ously published results for the elastic stratum.展开更多
The unsteady pulsatile flow of blood through porous medium in an artery has been studied under the influence of periodic body acceleration and slip condition by considering blood as incompressible Newtonian electrical...The unsteady pulsatile flow of blood through porous medium in an artery has been studied under the influence of periodic body acceleration and slip condition by considering blood as incompressible Newtonian electrically conducting fluid in the presence of magnetic field. In this paper, a new technique of differential quadrature method is introduced to find numerical solution of non-linear partial differential equations such as the equation of motion of this problem “Navier-Stokes equation”. The presence of the nonlinearity in the problem leads to severe difficulties in the solution approximation. In construction of the numerical scheme “a new algorithm” a generalized differential quadrature method (GDQM) is to use for derivatives with respect to space variables of differential equations and for the time derivative applying fourth order RungeKutta Method (RKM). The GDQM changed the nonlinear partial differential equations into a system of nonlinear ordinary differential equations (ODEs). The obtained system of ODEs is solved by 4th order RKM. This combination of DQM and 4th order RKM gives a very good numerical technique for solving time dependent problems. The algorithm is coded in Matlab 7.14.0.739 and the simulations are run on a Pentium 4 CPU 900 MHz with 1 GB memory capacity. The effects of slip condition, magnetic field, porous medium, and body acceleration have been discussed. The numerical results show that the proposed method is more accurate and convergent than other numerical methods in literature. The method is illustrated and compared with the exact and analytical solutions and it is found that the proposed method gives a better accuracy and is quite easy to implement.展开更多
基金the Swedish Research Council (2016-06146,2019-02345)Swedish Research Council (grant no.2020-05223)+7 种基金the Swedish Research Council Formas,the Swedish Energy Agency (52473-1)the Wallenberg Foundation (2017.0186 and 2016.0059) for financial supportsupported by the National Research Foundation of Korea (NRF-2017M3A7B8065584 and 2020R1A4A1018516)Support from the National Natural Science Foundation of China (61774077)the Key Projects of Joint Fund of Basic and Applied Basic Research Fund of Guangdong Province (2019B1515120073)the Research Fund of Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology (No.2020B1212030010)Support from Sino-Danish Center for Education and ResearchSwedish Energy Agency (grant no.45420-1)
文摘All-polymer solar cells(all-PSCs)possess attractive merits including superior thermal stability and mechanical flexibility for large-area roll-to-roll processing.Introducing flexible conjugation-break spacers(FCBSs)into backbones of polymer donor(P_(D))or polymer acceptor(P_(A))has been demonstrated as an efficient approach to enhance both the photovoltaic(PV)and mechanical properties of the all-PSCs.However,length dependency of FCBS on certain all-PSC related properties has not been systematically explored.In this regard,we report a series of new non-conjugated P_(A)s by incorporating FCBS with various lengths(2,4,and 8 carbon atoms in thioalkyl segments).Unlike com-mon studies on so-called side-chain engineering,where longer side chains would lead to better solubility of those resulting polymers,in this work,we observe that the solubilities and the resulting photovoltaic/mechanical properties are optimized by a proper FCBS length(i.e.,C2)in P_(A) named PYTS-C2.Its all-PSC achieves a high efficiency of 11.37%,and excellent mechanical robustness with a crack onset strain of 12.39%,significantly superior to those of the other P_(A)s.These results firstly demonstrate the effects of FCBS lengths on the PV performance and mechanical properties of the all-PSCs,providing an effective strategy to fine-tune the structures of P_(A)s for highly efficient and mechanically robust PSCs.
基金supported in part by a grant from the US National Institutes of Health(P20 RR016478 from the INBRE Program of the National Center for Research Resources).
文摘Metastasis to distant sites is a severe treatment challenge and a major cause of death for breast cancer patients.Laser immunotherapy(LIT)is a novel technique,combining a selective photothermal therapy with local application of glycated chitosan,a potent immunoadjuvant.The pre-clinical studies of LIT have shown its unique characteristics in generating specific antitumor immunity.The clinical application of LIT in the treatment of melanoma patients has achieved preliminary success.Recently,LIT has been used to treat late-stage breast cancer patients.Here we report for the first time the clinical results of this combination therapy in breast cancer patients.The LIT treatment procedures are presented and the medical history of two stage Ⅳ breast cancer patients is reviewed.Most of the breast cancer lesions and the metastasis of lung and brain disappeared after repeated treatments of LIT.One patient achieved complete response;the other achieved partial response at the time of this report.Although there is still a long way for LIT to become a standard modality for breast cancer treatment,the results of this study indicated its promising future.
文摘The purpose of this paper is to propose a new multi stage algorithm for the recognition of isolated characters. It was similar work done before using only the center of gravity (This paper is extended version of “A fast recognition system for isolated printed characters using center of gravity”, LAP LAMBERT Academic Publishing 2011, ISBN: 978-38465-0002-6), but here we add using principal axis in order to make the algorithm rotation invariant. In my previous work which is published in LAP LAMBERT, I face a big problem that when the character is rotated I can’t recognize the character. So this adds constrain on the document to be well oriented but here I use the principal axis in order to unify the orientation of the character set and the characters in the scanned document. The algorithm can be applied for any isolated character such as Latin, Chinese, Japanese, and Arabic characters but it has been applied in this paper for Arabic characters. The approach uses normalized and isolated characters of the same size and extracts an image signature based on the center of gravity of the character after making the character principal axis vertical, and then the system compares these values to a set of signatures for typical characters of the set. The system then provides the closeness of match to all other characters in the set.
文摘In this paper, two different numerical schemes, namely the Runge-Kutta fourth order method and the implicit Euler method with perturbation method of the second degree, are applied to solve the nonlinear thermal wave in one and two dimensions using the differential quadrature method. The aim of this paper is to make comparison between previous numerical schemes and detect which is more efficient and more accurate by comparing the obtained results with the available analytical ones and computing the computational time.
基金The current study is part of the ongoing activities in CHARMEC-Chalmers Railway Mechanics(www.chalmers.se/charmec).Parts of the study have been funded from the European Union’s Horizon 2020 research and innovation programme in the projects In2Track,In2Track2 and In2Track3 under Grant Agreements Nos.826255 and 101012456The simulations were performed using resources at Chalmers Centre for Computational Science and Engineering(C3SE)provided by the Swedish National Infrastructure for Computing(SNIC).
文摘Block braked railway wheels are subjected to thermal and rolling contact loading.The thermal loading results in high temperatures and thermal stresses which cause slow time dependent processes such as creep,relaxation and static recovery of the wheel material.At the same time,the rolling contact loading implies a very fast mechanical load application.This paper is focused on material modeling of pearlitic steel for a wide range of loading rates at elevated temperatures.The starting point is a viscoplasticity model including nonlinear isotropic and kinematic hardening.The Delobelle overstress function is employed to capture strain rate dependent response of the material.The model also includes static recovery of the hardening to capture slower viscous(diffusion dominated)behaviour of the material.Experiments for the pearlitic wheel steel ER7 in terms of cyclic strain-controlled uniaxial tests with hold-time,uniaxial ratchetting tests including rapid cycles and biaxial cyclic tests with tension/compression and torsion are used to calibrate the material model.These experiments were performed under isothermal conditions at different temperatures.In the ratchetting tests,higher loading rates are obtained and these have been used to calibrate the high strain rate response of the viscoplasticity model.The paper is concluded with a numerical example of a block braked wheel where the importance of accounting for the viscoplasticity in modelling is highlighted.
文摘Four numerical schemes are introduced for the analysis of photocurrent transients in organic photovoltaic devices.Themathematicalmodel for organic polymer solar cells contains a nonlinear diffusion-reaction partial differential equation system with electrostatic convection attached to a kinetic ordinary differential equation.To solve the problem,Polynomial-based differential quadrature,Sinc,and Discrete singular convolution are combined with block marching techniques.These schemes are employed to reduce the problem to a nonlinear algebraic system.The iterative quadrature technique is used to solve the reduced problem.The obtained results agreed with the previous exact one and the finite element method.Further,the effects of different times,different mobilities,different densities,different geminate pair distances,different geminate recombination rate constants,different generation efficiencies,and supporting conditions on photocurrent have been analyzed.The novelty of this paper is that these schemes for photocurrent transients in organic polymer solar cells have never been presented before,so the results may be useful for improving the performance of solar cells.
文摘The processes of tsunami evolution during its generation in search for possible amplification mechanisms resulting from unilateral spreading of the sea floor uplift is investigated. We study the nature of the tsunami build up and propagation during and after realistic curvilinear source models represented by a slowly uplift faulting and a spreading slip-fault model. The models are used to study the tsunami amplitude amplification as a function of the spreading velocity and rise time. Tsunami waveforms within the frame of the linearized shallow water theory for constant water depth are analyzed analytically by transform methods (Laplace in time and Fourier in space) for the movable source models. We analyzed the normalized peak amplitude as a function of the propagated uplift length, width and the average depth of the ocean along the propagation path.
文摘Bis[1-methoxy-2,2,2-tris-(pyrazol-l-yl-KN2)ethane]-copper(Ⅱ) bis-perchlorate (2) was synthesized by reacting of pyrazole based tripodal scorpionate ligand 1-methoxy-2,2,2-tris(pyrazol-1-yl)ethane (1) with copper(Ⅱ) perchlorate hexahydrate in methanol, acetonitrile and water mixture as solvent. Slow evaporation of the filtered reaction mixture in air produced blue color block crystals suitable for single crystal X-ray diffraction study of the title complex. Compound 2 crystallizes in the monoclinic space group P21/n with unit cell parameters, α = 8.1269(1) ,A, b = 21.8348(2)A, c = 9.1522(1) A, a = γ= 90° , β = 99.7611 (4)°. The structure of the compound was characterized by IR Spectroscopy, elemental analysis and single crystal X-ray diffraction analysis.
文摘The paper investigates the numerical solution of the magnetohydrodynamics (MHD) boundary layer flow of non-Newtonian Casson fluid on a moving wedge with heat and mass transfer. The effects of thermal diffusion and diffusion thermo with induced magnetic field are taken in consideration. The governing partial differential equations are transformed into nonlinear ordinary differential equations by applying the similarity transformation and solved numerically by using finite difference method (FDM). The effects of various governing parameters, on the velocity, temperature and concentration are displayed through graphs and discussed numerically. In order to verify the accuracy of the present results, we have compared these results with the analytical solutions by using the differential transform method (DTM). It is observed that this approximate numerical solution is in good agreement with the analytical solution. Furthermore, comparisons of the present results with previously published work show that the present results have high accuracy.
文摘The paper investigates the numerical solution of problem of magnetohydrodynamic (MHD) micropolar fluid flow with heat and mass transfer towards a stagnation point on a vertical plate. In this study, we consider both strong concentrations (n = 0) and weak concentrations (n = 1/2). The governing equations have been transformed into nonlinear ordinary differential equations by applying the similarity transformation and have been solved numerically by using the finite difference method (FDM) and analytically by using (DTM). The effects of various governing parameters, namely, material parameter, radiation parameter, magnetic parameter, Prandtl number, Schmidt number, chemical reaction parameter and Soret number on the velocity, microrotation, temperature and concentration have been computed and discussed in detail through some figures and tables. In order to verify the accuracy of the present results, we have compared these results with the analytical solutions by using the differential transform method (DTM) and the multi-step differential transform method (MDTM). It is observed that this approximate numerical solution is in good agreement with the analytical solution.
基金the Deanship of Scientific Research at King Khalid University for funding their work through Research Group Program under grant number(G.P.1/160/40)。
文摘We deal with the Wick-type stochastic fractional Korteweg de–Vries(KdV) equation with conformable derivatives.With the aid of the Exp-function method, white noise theory, and Hermite transform, we produce a novel set of exact soliton and periodic wave solutions to the fractional KdV equation with conformable derivatives. With the help of inverse Hermite transform, we get stochastic soliton and periodic wave solutions of the Wick-type stochastic fractional KdV equation with conformable derivatives. Eventually, by an application example, we show how the stochastic solutions can be given as Brownian motion functional solutions.
文摘This study examines the hydrodynamic performance of multiple-row vertical slotted breakwaters. We developed a mathematical model based on an eigenfunction expansion method and a least squares technique for Stokes second-order waves. The numerical results obtained for limiting cases of double-row and triple-row walls are in good agreement with results of previous studies and experimental results. Comparisons with experimental measurements of the reflection, transmission, and dissipation coefficients (CR, Cr, and CE) for double-row walls show that the proposed mathematical model adequately reproduces most of the important features. We found that for double-row walls, the CR increases with increasing wave number, kd, and with a decreasing permeable wall part, din. The Cr follows the opposite trend. The CE slowly increases with an increasing kd for lower kd values, reaches a maximum, and then decreases again. In addition, an increasing porosity of dm would significantly decrease the CR while increasing the Cr. At lower values of kd, a decreasing porosity increases the CE, but for high values of kd, a decreasing porosity reduces the Ce. The numerical results indicate that, for triple-row walls, the effect of the arrangement of the chamber widths on hydrodynamic characteristics is not significant, except when kd〈0.5 Double-row slotted breakwaters may exhibit a good wave-absorbing performance at kd〉0.5, where by the horizontal wave force may be smaller than that of a single wall. On the other hand, the difference between double-row and triple-row vertical slotted breakwaters is marginal.
基金supported in part by grants from the US National Institutes of Health(R21 EB0155091),the US Fulbright Scholar Program and Immunophotonics,IncThis work was also supported in part by grants from National Natural Science Foundation of China(No.81000994)Beijing Municipal Science and Technology Com-mission(No.Z121107001012080).
文摘Anti-tunor immunological response induced by local intervention is ideal for treatment of metastatic tumors.Laser immunot herapy was developed to synergize photot hermal interaction with immunological stimulation for cancer treatment.Using an infrared laser,indocyanine green(ICG,as a light abeorbing agent),and glycated chitosan(GC,as an immunostimulant),.laser imm unot herapy has resulted in tumor suppression and anti-tumor responses in pre-clinical as well as clinical studies.To further understand the mechanism of laser immunotherapy,the efects of laser and GC treatment without specifc enhancement of laser absorption were studied.Passive adoptive immunity transfer was perfomed using splenocytes as immune cells.Spleen cells harvested from tumor-bearing mice treated by laser+GC provided 60%immunity in naive recipients.Furthermore,cytotoxicity and TNF-ar secretion by splenocytes from treated mice also indicated that laser+GC induced immunity was tumor-specific.The high level of infiltrating T cells in tumors after laser+GC treatment furt her confirned a specific anti-tumor immune response.Therefore,laser+GC could prove to be a promisi ng selective local trea tment modality that induces a systemic anti-tumor response,with appropriate laser parameters and GC doses.
文摘The peristaltic pumping of a viscous compressible liquid mixed with rigid spherical particles of the same size in a channel is theoretically investigated. The momentum equations for the compressible flow are solved with a perturbation analysis. The analysis is carried out by duly accounting for the nonlinear convective acceleration terms for the fluid part on the wavy wall. The zeroth-order terms yield the Poiseuille flow, and the first-order terms give the Orr-Sommerfeld equation. The explicit expression for the net axial velocity is derived. The effects of the embedded parameters on the axial fluid velocity are studied through different engineering applications. The features of the flow characteristics are analyzed and discussed in detail. The obtained results are evaluated for various parameters associated with the blood flow in the blood vessels with diameters less than 5 500 μm, whereas the particle diameter has been taken to be 8 μm. This study provides a scope to evaluate the effect of the theory of two-phase flow characteristics with compressible fluid problems, and is helpful for understanding the role of engineering applications of pumping solid-fluid mixture by peristaltically driven motion.
文摘The present work is concerned with the problem of mode Ⅲ crack perpendicular to the interface of a bi-strip composite. One of these strips is made of a functionally graded material and the other of an isotropic material, which contains an edge crack perpendicular to and terminating at the interface. Fourier transforms and asymptotic analysis are employed to reduce the problem to a singular integral equation which is numerically solved using Gauss-Chebyshev quadrature formulae. Furthermore, a parametric study is carried out to investigate the effects of elastic and geometric characteristics of the composite on the values of stress intensity factor.
基金the National Natural Science Foundation of China(30627003,30870676,30870658)the Natural Science Foundation of Guangdong Province(7117865)as well as by a grant from the US National Institute of Health(P20 RR016478 from the INBRE Program of the National Center for Research Resources).
文摘Apoptosis is an important cellular event that plays a key role in the therapy of many diseases.The mechanism of the initiation and regulation of photodynamic therapy(PDT)–induced apoptosis is complex.Our previous study found that Photofrin was localized primarily in mitochondria,the primary targets of Photofrin-PDT.The key role of Bax in the mitochondria-mediated apoptosis has been demonstrated in many systems.In order to determine the role of Bax in the mitochondrion-mediated apoptosis induced by Photofrin-PDT,we used the GFP-Bax plasmid to monitor the dynamics of Bax activation after PDT treatment.With laser scanning confocal microscopy,we found that Bax did not translocate from the cytosol to mitochondria when the mitochondrial membrane potential(∆Ψm)disappeared,measured by TMRM.Thus,for Photofrin-PDT,the commitment to cell death is independent of Bax activation.
基金supported by the National Basic Research Program of China(2011CB910402,2010CB732602)the Program for Changjiang Scholars and Innovative Research Team in University(IRT0829)the National Natural Science Foundation of China(30870676,30870658).
文摘Microglial activation plays an important role in neurodegenerative diseases.Once activated,they have macrophage-like capabilities,which can be beneficial by phagocytosis and harmful by se-cretion of neurotoxins.However,the resident microglia always fail to trigger an effective pha-gocytic response to clear dead cells or Aβdeposits during the progression of neurodegeneration.Therefore,the regulation of microglial phagocytosis is considered a useful strategy in searchingfor neuroprotective treatments.In this study,our results showed that low-power laser iradiation(LPLI)(20 J/cm²)could enhance microglial phagocytic function in LPS-activated microglia.Wefound that LPLI-mediated microglial phagocytosis is a Rac-1-dependent actin-based process,that a constitutively activated form of Rac1(RaclQ61L)induced a higher level of actin pol-ymerization than cells transfected with wild-type Racl,whereas a dominant negative form ofRacl(RaclT17N)markedly suppressed actin polymerization.In addition,the involvement of Racl activation after LPLI treatment was also observed by using a Raichu fluorescence resonance energy transfer(FRET)-based biosensor.We also found that PI3K/Akt pathway was required inthe LPLI-induced Raci activation.Our research may provide a feasible therapeutic approach tocontrol the progression of neurodegenerative diseases.
基金The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding their work through General Research Project under grant number(GRP-114-41).
文摘In this paper,the non-stationary incompressible fluid flows governed by the Navier-Stokes equations are studied in a bounded domain.This study focuses on the time-fractional Navier-Stokes equations in the optimal control subject,where the control is distributed within the domain and the time-fractional derivative is proposed as Riemann-Liouville sort.In addition,the control object is to minimize the quadratic cost functional.By using the Lax-Milgram lemma with the assistance of the fixed-point theorem,we demonstrate the existence and uniqueness of the weak solution to this system.Moreover,for a quadratic cost functional subject to the time-fractional Navier-Stokes equations,we prove the existence and uniqueness of optimal control.Also,via the variational inequality upon introducing the adjoint linearized system,some inequalities and identities are given to guarantee the first-order necessary optimality conditions.A direct consequence of the results obtained here is that when a→1,the obtained results are valid for the classical optimal control of systems governed by the Navier-Stokes equations.
文摘Reflection characteristics of longitudinal strain waves in a semi-infinite elastic rod con- nected to a viscoelastic stratum are investigated analytically.The three-dimensional viscoelasticity the- ory is applied to the stratum,and the Laplace transform with respect to time and the numerical inverse Laplace transform by means of Laguerre function are used.The time histories for the longitudinal strain of an arbitrary point of the rod are presented.Two typical viscoelastic models are considered, one is the usual Maxwell-Voigt model,the other is whose relaxation function is given by a power law. The numerical results for the two models are presented and compared each other and also with previ- ously published results for the elastic stratum.
文摘The unsteady pulsatile flow of blood through porous medium in an artery has been studied under the influence of periodic body acceleration and slip condition by considering blood as incompressible Newtonian electrically conducting fluid in the presence of magnetic field. In this paper, a new technique of differential quadrature method is introduced to find numerical solution of non-linear partial differential equations such as the equation of motion of this problem “Navier-Stokes equation”. The presence of the nonlinearity in the problem leads to severe difficulties in the solution approximation. In construction of the numerical scheme “a new algorithm” a generalized differential quadrature method (GDQM) is to use for derivatives with respect to space variables of differential equations and for the time derivative applying fourth order RungeKutta Method (RKM). The GDQM changed the nonlinear partial differential equations into a system of nonlinear ordinary differential equations (ODEs). The obtained system of ODEs is solved by 4th order RKM. This combination of DQM and 4th order RKM gives a very good numerical technique for solving time dependent problems. The algorithm is coded in Matlab 7.14.0.739 and the simulations are run on a Pentium 4 CPU 900 MHz with 1 GB memory capacity. The effects of slip condition, magnetic field, porous medium, and body acceleration have been discussed. The numerical results show that the proposed method is more accurate and convergent than other numerical methods in literature. The method is illustrated and compared with the exact and analytical solutions and it is found that the proposed method gives a better accuracy and is quite easy to implement.