A modified inner-element edge-based smoothed finite element method(IES-FEM)is developed and integrated with ABAQUS using a user-defined element(UEL)in this study.Initially,the smoothing domain discretization of IES-FE...A modified inner-element edge-based smoothed finite element method(IES-FEM)is developed and integrated with ABAQUS using a user-defined element(UEL)in this study.Initially,the smoothing domain discretization of IES-FEM is described and compared with ES-FEM.A practical modification of IES-FEM is then introduced that used the technique employed by ES-FEM for the nodal strain calculation.The differences in the strain computation among ES-FEM,IES-FEM,and FEM are then discussed.The modified IES-FEM exhibited superior performance in displacement and a slight advantage in stress compared to FEM using the same mesh according to the results obtained from both the regular and irregular elements.The robustness of the IES-FEM to severely deformed meshes was also verified.展开更多
We study the Cauchy problem of the Kolmogorov-Fokker-Planck equations and show that the solution enjoys an analytic smoothing effect with L?initial datum for positive time.
Vein graft(VG)failure(VGF)is associated with VG intimal hyperplasia,which is characterized by abnormal accumulation of vascular smooth muscle cells(VSMCs).Most neointimal VSMCs are derived from pre-existing VSMCs via ...Vein graft(VG)failure(VGF)is associated with VG intimal hyperplasia,which is characterized by abnormal accumulation of vascular smooth muscle cells(VSMCs).Most neointimal VSMCs are derived from pre-existing VSMCs via a process of VSMC phenotypic transition,also known as dedifferentiation.There is increasing evidence to suggest that ginger or its bioactive ingredients may block VSMC dedifferentiation,exerting vasoprotective functions;however,the precise mechanisms have not been fully characterized.Therefore,we investigated the effect of ginger on VSMC phenotypic transition in VG remodeling after transplantation.Ginger significantly inhibited neointimal hyperplasia and promoted lumen(L)opening in a 3-month VG,which was primarily achieved by reducing ferroptotic stress.Ferroptotic stress is a pro-ferroptotic state.Contractile VSMCs did not die but instead gained a proliferative capacity and switched to the secretory type,forming neointima(NI)after vein transplantation.Ginger and its two main vasoprotective ingredients(6-gingerol and 6-shogaol)inhibit VSMC dedifferentiation by reducing ferroptotic stress.Network pharmacology analysis revealed that 6-gingerol inhibits ferroptotic stress by targeting P53,while 6-shogaol inhibits ferroptotic stress by targeting 5-lipoxygenase(Alox5),both promoting ferroptosis.Furthermore,both ingredients co-target peroxisome proliferator-activated receptor gamma(PPARγ),decreasing PPARγ-mediated nicotinamide adenine dinucleotide phosphate(NADPH)oxidase 1(Nox1)expression.Nox1 promotes intracellular reactive oxygen species(ROS)production and directly induces VSMC dedifferentiation.In addition,Nox1 is a ferroptosis-promoting gene that encourages ferroptotic stress production,indirectly leading to VSMC dedifferentiation.Ginger,a natural multi-targeted ferroptotic stress inhibitor,finely and effectively prevents VSMC phenotypic transition and protects against venous injury remodeling.展开更多
The interaction between extreme waves and structures is a crucial study area in marine science,as it significantly influences safety and disaster prevention strategies for marine and coastal engineering.To investigate...The interaction between extreme waves and structures is a crucial study area in marine science,as it significantly influences safety and disaster prevention strategies for marine and coastal engineering.To investigate the flow field of a semi-submersible against extreme waves,a model simulating solitary wave interactions with the semi-submersible system was developed via the meshless smoothed particle hydrodynamics(SPH)method and Rayleigh’s theory.Notably,the wave surface and wave load results obtained from the SPH model,compared with those of OpenFOAM,result in an interaction test case between solitary waves and partially submerged rectangular obstacles and show good agreement,with a maximum relative error of 3.4%.An analysis of the calculated results of the semi-submersible facing solitary waves revealed several key findings:overtopping,which decreases with increasing water depth,occurs on the structure when the non-submerged ratio is 0.33 and the wave height surpasses 0.2 m.The transmission coefficient decreases with increasing wave height but increases as the water depth increases.Furthermore,the reflection coefficient peaks at a wave height H0=0.2 m.The dissipation coefficient displays a valley trend with a small water depth,whereas it increases monotonically with increasing water depth.The dissipation coefficient decreases with increasing water depth.展开更多
Adversarial attacks pose a significant threat to artificial intelligence systems by exposing them to vulnerabilities in deep learning models.Existing defense mechanisms often suffer drawbacks,such as the need for mode...Adversarial attacks pose a significant threat to artificial intelligence systems by exposing them to vulnerabilities in deep learning models.Existing defense mechanisms often suffer drawbacks,such as the need for model retraining,significant inference time overhead,and limited effectiveness against specific attack types.Achieving perfect defense against adversarial attacks remains elusive,emphasizing the importance of mitigation strategies.In this study,we propose a defense mechanism that applies random cropping and Gaussian filtering to input images to mitigate the impact of adversarial attacks.First,the image was randomly cropped to vary its dimensions and then placed at the center of a fixed 299299 space,with the remaining areas filled with zero padding.Subsequently,Gaussian×filtering with a 77 kernel and a standard deviation of two was applied using a convolution operation.Finally,the×smoothed image was fed into the classification model.The proposed defense method consistently appeared in the upperright region across all attack scenarios,demonstrating its ability to preserve classification performance on clean images while significantly mitigating adversarial attacks.This visualization confirms that the proposed method is effective and reliable for defending against adversarial perturbations.Moreover,the proposed method incurs minimal computational overhead,making it suitable for real-time applications.Furthermore,owing to its model-agnostic nature,the proposed method can be easily incorporated into various neural network architectures,serving as a fundamental module for adversarial defense strategies.展开更多
The traditional topology optimization method of continuum structure generally uses quadrilateral elements as the basic mesh.This approach often leads to jagged boundary issues,which are traditionally addressed through...The traditional topology optimization method of continuum structure generally uses quadrilateral elements as the basic mesh.This approach often leads to jagged boundary issues,which are traditionally addressed through post-processing,potentially altering the mechanical properties of the optimized structure.A topology optimization method of Movable Morphable Smooth Boundary(MMSB)is proposed based on the idea of mesh adaptation to solve the problem of jagged boundaries and the influence of post-processing.Based on the ICM method,the rational fraction function is introduced as the filtering function,and a topology optimization model with the minimum weight as the objective and the displacement as the constraint is established.A triangular mesh is utilized as the base mesh in this method.The mesh is re-divided in the optimization process based on the contour line,and a smooth boundary parallel to the contour line is obtained.Numerical examples demonstrate that the MMSB method effectively resolves the jagged boundary issues,leading to enhanced structural performance.展开更多
Background:Mechanical ventilation(MV)provides life support for patients with severe respiratory distress but can simultaneously cause ventilator-induced lung injury(VILI).However,due to a poor understanding of its mec...Background:Mechanical ventilation(MV)provides life support for patients with severe respiratory distress but can simultaneously cause ventilator-induced lung injury(VILI).However,due to a poor understanding of its mechanism,there is still a lack of effective remedies for the often-deadly VILI.Recent studies indicate that the stretch associated with MV can enhance the secretion of extracellular vesicles(EVs)and induce endoplasmic reticulum(ER)stress in airway smoothmuscle cells(ASMCs),both of which can contribute to VILI.But whetherMVassociated stretch enhances the secretion of EVs via ER stress in ASMCs as an underlying mechanism of VILI remains unknown.Methods:In this study,we exposed cultured human ASMCs to stretch(13%strain)and mouse models to MV at tidal volume(18 mL/kg).Subsequently,the amount of secreted EVs in the culture medium of ASMCs and the bronchoalveolar lavage fluid(BALF)of mousemodels was quantitatively evaluated by ultracentrifugation,transmission electron microscopy,Western blot,flow cytometry,and nanoparticle tracking analysis.The cultured ASMCs and the lung tissues of mouse models were assessed for expression of biomarkers of EVs(cluster of differentiation antigen 63,CD63),ER stress(heat shock protein family A member 5,HSPA5),and EVs regulating molecule Rab27a by immunofluorescence microscopy,immunohistochemistry(IHC)and enzyme-linked immunosorbent assay(ELISA),respectively.MicroRNAs(miRNAs)in EVs from ASMCs were measured with miRNA whole genome sequencing(miRNA-Seq).Results:We found that stretch enhanced EV secretion from cultured ASMCs.In addition,the cultured ASMCs and the mouse models were either or not pretreated with ER stress inhibitor(tauroursodeoxycholic acid,TUDCA)/EV secretion inhibitor(GW4869)prior to stretch or MV.We found that MV-associated stretch enhanced the expression of CD63,HSPA5,and Rab27a in cultured ASMCs and BALF/lung tissues of mousemodels,which could all be attenuated with TUDCA/GW4869 pretreatment.miRNA-Seq data show that differentially expressed miRNAs in EVsmainlymodulate gene transcription.Furthermore,the EVs fromcultured ASMCs under stretch tended to enhance detachment and expression of inflammatory cytokines,i.e.,transforming growth factor-β1(TGF-β1),interleukin-10(IL-10)in cultured airway epithelial cells.The expression of TGF-β1 and IL-10 in BALF of the mouse models also increased in response to MV,which was attenuated together with partial improvement of lung injury by pretreatment with TUDCA,GW4869/Rab27a siRNAs.Conclusion:Taken together,our data indicate thatMV-associated stretch can enhance the secretion of EVs from ASMCs via ER stress signaling to mediate airway inflammation and VILI,which provides new insight for further exploring EVs for the diagnosis and treatment of VILI.展开更多
A discontinuous smoothed particle hydrodynamics(DSPH)method considering block contacts is originally developed to model the cracking,frictional slip and large deformation in rock masses,and is verified by theoretical,...A discontinuous smoothed particle hydrodynamics(DSPH)method considering block contacts is originally developed to model the cracking,frictional slip and large deformation in rock masses,and is verified by theoretical,numerical and/or experimental results.In the DSPH method,cracking is realized by breaking the virtual bonds via a pseudo-spring method based on Mohr–Coulomb failure criteria.The damaged particles are instantaneously replaced by discontinuous particles and the contact bond between the original and discontinuous particles is formed to simulate the frictional slip and separation/contraction between fracture surfaces based on the block contact algorithm.The motion of rock blocks and the contact force of discontinuous particles are determined following Newton's second law.The results indicate that the DSPH method precisely captures the cracking,contact formation and complete failure across six numerical benchmark tests.This single smoothed particle hydrodynamics(SPH)framework could significantly improve computational efficiency and is potentially applicable to broad multi-physical rock engineering problems of different scales.展开更多
This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanis...This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanism is presented to structure the adaptive integral terminal sliding mode control(SMC)strategy.The control design consists of compensation control and nominal control,which improves the rapidity and accuracy of trajectory tracking.The smooth saturation model based on the error function is applied to approximate the voltage saturation phenomenon.Additionally,to deal with the adverse effects of various unknown disturbances,including model parameter uncertainties and unknown external load disturbances,an improved disturbance observer(DO)is proposed.This observer effectively suppresses the fluctuations caused by fixed gain during the starting period of the system.Finally,the experimental results under different conditions show that the proposed strategy has good tracking and disturbance suppression performances.展开更多
Topology optimization stands as a pivotal technique in realizing periodic microstructure design.A novel approach is proposed,integrating the energy-based homogenization method with the Floating Projection Topology Opt...Topology optimization stands as a pivotal technique in realizing periodic microstructure design.A novel approach is proposed,integrating the energy-based homogenization method with the Floating Projection Topology Optimization(FPTO)method to achieve smooth topology design.The objective is to optimize the periodic microstructure to maximize the properties of specific materials,such as bulk modulus and shear modulus,or to achieve negative Poisson's ratio.Linear material interpolation is used to eliminate the nonlinear challenges and design dependence caused by material penalty.Furthermore,the three-field density representation technique is applied to augment length scales and solid/void characteristics.Through systematic analysis and numerical simulations,the impacts of various initial designs and optimization parameters on the optimization outcomes are investigated.The results demonstrate that the optimized periodic microstructures exhibit extreme performance with clear boundaries.The identification of appropriate optimization parameters is crucial for enhancing the extreme mechanical properties of material microstructures.It can provide valuable guidance for aerospace component design involving material microstructures and metamaterials.展开更多
Combining TT* argument and bilinear interpolation,this paper obtains the Strichartz and smoothing estimates of dispersive semigroup e^(-itP(D)) in weighted L^(2) spaces.Among other things,we recover the results in[1]....Combining TT* argument and bilinear interpolation,this paper obtains the Strichartz and smoothing estimates of dispersive semigroup e^(-itP(D)) in weighted L^(2) spaces.Among other things,we recover the results in[1].Moreover,the application of these results to the well-posedness of some equations are shown in the last section.展开更多
We present a hybrid smoothed particle magnetohydrodynamics(SPMHD)code integrating smoothed particle hydrodynamics(SPH)and finite element methods(FEM)to simulate coupled fluid-electromagnetic phenomena.The framework em...We present a hybrid smoothed particle magnetohydrodynamics(SPMHD)code integrating smoothed particle hydrodynamics(SPH)and finite element methods(FEM)to simulate coupled fluid-electromagnetic phenomena.The framework employs SPH for fluid dynamics,addressing large deformations,shocks,and plasma behavior,while FEM resolves electromagnetic fields via Maxwell's equations for magnetic vector and electric scalar potentials,ensuring divergence-free conditions and global current density calculations in conductive region.Operator splitting method couples these modules,enabling real-time integration of magnetic,electric,thermal,and fluid fields.Benchmark tests validate the code against analytical solutions and existing models,including blow-by instability simulations that demonstrate the method's accuracy in capturing fluid-magnetic interactions.Designed for 3D applications,SPMHD offers robust scalability across multiprocessor architectures,establishing it as a versatile tool for plasma physics research.展开更多
OBJECTIVE:To explore the role and mechanism of Qufeng Jiejing(祛风解痉,QFJJ)formula in the asthma progression.METHODS:The Bagg Albino/c mice treated with Ovalbumin and AL(OH)3,and airway smooth muscle cells(ASMCs)trea...OBJECTIVE:To explore the role and mechanism of Qufeng Jiejing(祛风解痉,QFJJ)formula in the asthma progression.METHODS:The Bagg Albino/c mice treated with Ovalbumin and AL(OH)3,and airway smooth muscle cells(ASMCs)treated with platelet-derived growth factor(PDGF)-BB to establish a asthma model in vivo and in vitro.The cell morphology was observed with microscope and immunofluorescence staining.The cell viability was assessed with methyl thiazolyl tetrazolium assay.The tumor necrosis factor-αlpha(TNF-α),interleukin-1beta(IL-1β),laminin,fibronectin and collagen IV levels in the ASMCs were detected with corresponding enzyme linked immunosorbent assay kits.Transwell and wound healing assays were conducted to test the cell migration.The TGF-β1,Smad2 and Smad3 levels were measured with Western blot.RESULTS:We found that QFJJ formula treatment dramatically decreased the cell viability,TNF-α,IL-1β,laminin,fibronectin and collagen IV levels in the PDGFBB stimulated ASMCs.Additionally,the protein levels of TGF-β1,Smad2 and Smad3 in the PDGF-BB stimulated ASMCs were prominently depleted after QFJJ formula treatment.Besides,SRI treatment neutralized the role of QFJJ formula in the PDGF-BB stimulated ASMCs.CONCLUSION:QFJJ formula effectively relieved the asthma progression through ameliorate the ASMCs function,which was achieved through suppressing the TGF-β1/Smads signaling pathway.展开更多
The evaporation ofmicrometer and millimeter liquid drops,involving a liquid-to-vapor phase transition accompanied by mass and energy transfer through the liquid-vapor interface,is encountered in many natural and indus...The evaporation ofmicrometer and millimeter liquid drops,involving a liquid-to-vapor phase transition accompanied by mass and energy transfer through the liquid-vapor interface,is encountered in many natural and industrial processes as well as in numerous engineering applications.Therefore,understanding and predicting the dynamics of evaporating flows have become of primary importance.Recent efforts have been addressed using the method of Smoothed Particle Hydrodynamics(SPH),which has proven to be very efficient in correctly handling the intrinsic complexity introduced by the multiscale nature of the evaporation process.This paper aims to provide an overview of published work on SPH-based simulations related to the evaporation of drops suspended in static and convective environments and impacting on heated solid surfaces.After a brief theoretical account of the main ingredients necessary for the modeling of drop evaporation,the fundamental aspects of SPH are revisited along with the various existing formulations that have been implemented to address the challenges imposed by the physics of evaporating flows.In the following sections,the paper summarizes the results of SPH-based simulations of drop evaporation and ends with a few comments on the limitations of the current state-of-the-art SPHsimulations and future lines of research.展开更多
We demonstrate a new polarization smoothing(PS)approach utilizing residual stress birefringence in fused silica to create a spatially random polarization control plate(SRPCP),thereby improving target illumination unif...We demonstrate a new polarization smoothing(PS)approach utilizing residual stress birefringence in fused silica to create a spatially random polarization control plate(SRPCP),thereby improving target illumination uniformity in inertial confinement fusion(ICF)laser systems.The fundamental operating mechanism and key fabrication techniques for the SRPCP are systematically developed and experimentally validated.The SRPCP converts a linearly polarized 3ω incident laser beam into an output beam with a spatially randomized polarization distribution.When combined with a continuous phase plate,the SRPCP effectively suppresses high-intensity speckles at all spatial frequencies in the focal spot.The proposed PS technique is specifically designed for high-fluence large-aperture laser systems,enabling novel polarization control regimes in laser-driven ICF.展开更多
基金the National Natural Science Foundation of China(No.11672238)the 111 Project(No.BP0719007)the Shaanxi Province Natural Science Foundation(No.2020JZ-06)for the financial support.
文摘A modified inner-element edge-based smoothed finite element method(IES-FEM)is developed and integrated with ABAQUS using a user-defined element(UEL)in this study.Initially,the smoothing domain discretization of IES-FEM is described and compared with ES-FEM.A practical modification of IES-FEM is then introduced that used the technique employed by ES-FEM for the nodal strain calculation.The differences in the strain computation among ES-FEM,IES-FEM,and FEM are then discussed.The modified IES-FEM exhibited superior performance in displacement and a slight advantage in stress compared to FEM using the same mesh according to the results obtained from both the regular and irregular elements.The robustness of the IES-FEM to severely deformed meshes was also verified.
基金Supported by NSFC (No.12031006)Fundamental Research Funds for the Central Universities of China。
文摘We study the Cauchy problem of the Kolmogorov-Fokker-Planck equations and show that the solution enjoys an analytic smoothing effect with L?initial datum for positive time.
基金supported by grants from the Natural Science Foundation of Shandong Province,China(Grant Nos.:ZR2019ZD28 and ZR2022QH008)the National Natural Science Foundation of China(Grant Nos.:82270301 and 82200465)+1 种基金China Postdoctoral Science Foundation(Grant No.:2023M731842)Shandong Postdoctoral Science Foundation,China(Grant No.:SDCX-ZG-202203013).
文摘Vein graft(VG)failure(VGF)is associated with VG intimal hyperplasia,which is characterized by abnormal accumulation of vascular smooth muscle cells(VSMCs).Most neointimal VSMCs are derived from pre-existing VSMCs via a process of VSMC phenotypic transition,also known as dedifferentiation.There is increasing evidence to suggest that ginger or its bioactive ingredients may block VSMC dedifferentiation,exerting vasoprotective functions;however,the precise mechanisms have not been fully characterized.Therefore,we investigated the effect of ginger on VSMC phenotypic transition in VG remodeling after transplantation.Ginger significantly inhibited neointimal hyperplasia and promoted lumen(L)opening in a 3-month VG,which was primarily achieved by reducing ferroptotic stress.Ferroptotic stress is a pro-ferroptotic state.Contractile VSMCs did not die but instead gained a proliferative capacity and switched to the secretory type,forming neointima(NI)after vein transplantation.Ginger and its two main vasoprotective ingredients(6-gingerol and 6-shogaol)inhibit VSMC dedifferentiation by reducing ferroptotic stress.Network pharmacology analysis revealed that 6-gingerol inhibits ferroptotic stress by targeting P53,while 6-shogaol inhibits ferroptotic stress by targeting 5-lipoxygenase(Alox5),both promoting ferroptosis.Furthermore,both ingredients co-target peroxisome proliferator-activated receptor gamma(PPARγ),decreasing PPARγ-mediated nicotinamide adenine dinucleotide phosphate(NADPH)oxidase 1(Nox1)expression.Nox1 promotes intracellular reactive oxygen species(ROS)production and directly induces VSMC dedifferentiation.In addition,Nox1 is a ferroptosis-promoting gene that encourages ferroptotic stress production,indirectly leading to VSMC dedifferentiation.Ginger,a natural multi-targeted ferroptotic stress inhibitor,finely and effectively prevents VSMC phenotypic transition and protects against venous injury remodeling.
基金financially supported by the Basic and Applied Basic Research Foundation of Guangdong Province(Grant Nos.2023A1515010890 and 2022A1515240039)the National Natural Science Foundation of China(Grant No.52001071)+4 种基金the Special Fund Competition Allocation Project of Guangdong Science and Technology Innovation Strategy(Grant No.2023A01022)the Non-funded Science and Technology Research Program Project of Zhanjiang(Grant No.2021B01416)Student Innovation Team Project of Guangdong Ocean University(Grant No.CXTD2023012)the Doctor Initiate Projects of Guangdong Ocean University(Grant Nos.060302072103 and R20068)the Marine Youth Talent Innovation Project of Zhanjiang(Grant No.2021E05009).
文摘The interaction between extreme waves and structures is a crucial study area in marine science,as it significantly influences safety and disaster prevention strategies for marine and coastal engineering.To investigate the flow field of a semi-submersible against extreme waves,a model simulating solitary wave interactions with the semi-submersible system was developed via the meshless smoothed particle hydrodynamics(SPH)method and Rayleigh’s theory.Notably,the wave surface and wave load results obtained from the SPH model,compared with those of OpenFOAM,result in an interaction test case between solitary waves and partially submerged rectangular obstacles and show good agreement,with a maximum relative error of 3.4%.An analysis of the calculated results of the semi-submersible facing solitary waves revealed several key findings:overtopping,which decreases with increasing water depth,occurs on the structure when the non-submerged ratio is 0.33 and the wave height surpasses 0.2 m.The transmission coefficient decreases with increasing wave height but increases as the water depth increases.Furthermore,the reflection coefficient peaks at a wave height H0=0.2 m.The dissipation coefficient displays a valley trend with a small water depth,whereas it increases monotonically with increasing water depth.The dissipation coefficient decreases with increasing water depth.
基金supported by the Glocal University 30 Project Fund of Gyeongsang National University in 2025.
文摘Adversarial attacks pose a significant threat to artificial intelligence systems by exposing them to vulnerabilities in deep learning models.Existing defense mechanisms often suffer drawbacks,such as the need for model retraining,significant inference time overhead,and limited effectiveness against specific attack types.Achieving perfect defense against adversarial attacks remains elusive,emphasizing the importance of mitigation strategies.In this study,we propose a defense mechanism that applies random cropping and Gaussian filtering to input images to mitigate the impact of adversarial attacks.First,the image was randomly cropped to vary its dimensions and then placed at the center of a fixed 299299 space,with the remaining areas filled with zero padding.Subsequently,Gaussian×filtering with a 77 kernel and a standard deviation of two was applied using a convolution operation.Finally,the×smoothed image was fed into the classification model.The proposed defense method consistently appeared in the upperright region across all attack scenarios,demonstrating its ability to preserve classification performance on clean images while significantly mitigating adversarial attacks.This visualization confirms that the proposed method is effective and reliable for defending against adversarial perturbations.Moreover,the proposed method incurs minimal computational overhead,making it suitable for real-time applications.Furthermore,owing to its model-agnostic nature,the proposed method can be easily incorporated into various neural network architectures,serving as a fundamental module for adversarial defense strategies.
基金supported by the National Natural Science Foundation of China(Grant 12472113).
文摘The traditional topology optimization method of continuum structure generally uses quadrilateral elements as the basic mesh.This approach often leads to jagged boundary issues,which are traditionally addressed through post-processing,potentially altering the mechanical properties of the optimized structure.A topology optimization method of Movable Morphable Smooth Boundary(MMSB)is proposed based on the idea of mesh adaptation to solve the problem of jagged boundaries and the influence of post-processing.Based on the ICM method,the rational fraction function is introduced as the filtering function,and a topology optimization model with the minimum weight as the objective and the displacement as the constraint is established.A triangular mesh is utilized as the base mesh in this method.The mesh is re-divided in the optimization process based on the contour line,and a smooth boundary parallel to the contour line is obtained.Numerical examples demonstrate that the MMSB method effectively resolves the jagged boundary issues,leading to enhanced structural performance.
基金funded by the Natural Science Foundation of China(NSFC),Grants No.12072048 to M.L.,12272063,and 11532003 to L.D.partially supported by the Science and Technology Innovation Leading Plan of High-Tech Industry in Hunan Province,China,Grant No.2020SK2018 to L.D.
文摘Background:Mechanical ventilation(MV)provides life support for patients with severe respiratory distress but can simultaneously cause ventilator-induced lung injury(VILI).However,due to a poor understanding of its mechanism,there is still a lack of effective remedies for the often-deadly VILI.Recent studies indicate that the stretch associated with MV can enhance the secretion of extracellular vesicles(EVs)and induce endoplasmic reticulum(ER)stress in airway smoothmuscle cells(ASMCs),both of which can contribute to VILI.But whetherMVassociated stretch enhances the secretion of EVs via ER stress in ASMCs as an underlying mechanism of VILI remains unknown.Methods:In this study,we exposed cultured human ASMCs to stretch(13%strain)and mouse models to MV at tidal volume(18 mL/kg).Subsequently,the amount of secreted EVs in the culture medium of ASMCs and the bronchoalveolar lavage fluid(BALF)of mousemodels was quantitatively evaluated by ultracentrifugation,transmission electron microscopy,Western blot,flow cytometry,and nanoparticle tracking analysis.The cultured ASMCs and the lung tissues of mouse models were assessed for expression of biomarkers of EVs(cluster of differentiation antigen 63,CD63),ER stress(heat shock protein family A member 5,HSPA5),and EVs regulating molecule Rab27a by immunofluorescence microscopy,immunohistochemistry(IHC)and enzyme-linked immunosorbent assay(ELISA),respectively.MicroRNAs(miRNAs)in EVs from ASMCs were measured with miRNA whole genome sequencing(miRNA-Seq).Results:We found that stretch enhanced EV secretion from cultured ASMCs.In addition,the cultured ASMCs and the mouse models were either or not pretreated with ER stress inhibitor(tauroursodeoxycholic acid,TUDCA)/EV secretion inhibitor(GW4869)prior to stretch or MV.We found that MV-associated stretch enhanced the expression of CD63,HSPA5,and Rab27a in cultured ASMCs and BALF/lung tissues of mousemodels,which could all be attenuated with TUDCA/GW4869 pretreatment.miRNA-Seq data show that differentially expressed miRNAs in EVsmainlymodulate gene transcription.Furthermore,the EVs fromcultured ASMCs under stretch tended to enhance detachment and expression of inflammatory cytokines,i.e.,transforming growth factor-β1(TGF-β1),interleukin-10(IL-10)in cultured airway epithelial cells.The expression of TGF-β1 and IL-10 in BALF of the mouse models also increased in response to MV,which was attenuated together with partial improvement of lung injury by pretreatment with TUDCA,GW4869/Rab27a siRNAs.Conclusion:Taken together,our data indicate thatMV-associated stretch can enhance the secretion of EVs from ASMCs via ER stress signaling to mediate airway inflammation and VILI,which provides new insight for further exploring EVs for the diagnosis and treatment of VILI.
基金financial support from the National Key Research and Development Program of China(Grant No.2019YFC1509702)the Fundamental Research Funds for the Central Universities in Chinathe National Natural Science Foundation of China(Grant No.42377162).
文摘A discontinuous smoothed particle hydrodynamics(DSPH)method considering block contacts is originally developed to model the cracking,frictional slip and large deformation in rock masses,and is verified by theoretical,numerical and/or experimental results.In the DSPH method,cracking is realized by breaking the virtual bonds via a pseudo-spring method based on Mohr–Coulomb failure criteria.The damaged particles are instantaneously replaced by discontinuous particles and the contact bond between the original and discontinuous particles is formed to simulate the frictional slip and separation/contraction between fracture surfaces based on the block contact algorithm.The motion of rock blocks and the contact force of discontinuous particles are determined following Newton's second law.The results indicate that the DSPH method precisely captures the cracking,contact formation and complete failure across six numerical benchmark tests.This single smoothed particle hydrodynamics(SPH)framework could significantly improve computational efficiency and is potentially applicable to broad multi-physical rock engineering problems of different scales.
基金supported by the National Natural Science Foundation under Grant 62273189the Shandong Province Natural Science Foundation under Grant ZR2021MF005Systems Science Plus Joint Research Program of Qingdao University under Grant XT2024201 of China supporting this research work.
文摘This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanism is presented to structure the adaptive integral terminal sliding mode control(SMC)strategy.The control design consists of compensation control and nominal control,which improves the rapidity and accuracy of trajectory tracking.The smooth saturation model based on the error function is applied to approximate the voltage saturation phenomenon.Additionally,to deal with the adverse effects of various unknown disturbances,including model parameter uncertainties and unknown external load disturbances,an improved disturbance observer(DO)is proposed.This observer effectively suppresses the fluctuations caused by fixed gain during the starting period of the system.Finally,the experimental results under different conditions show that the proposed strategy has good tracking and disturbance suppression performances.
基金supported by the financial support from the National Natural Science Foundation of China(No.52172356)Hunan Provincial Natural Science Foundation of China(No.2022JJ10012)。
文摘Topology optimization stands as a pivotal technique in realizing periodic microstructure design.A novel approach is proposed,integrating the energy-based homogenization method with the Floating Projection Topology Optimization(FPTO)method to achieve smooth topology design.The objective is to optimize the periodic microstructure to maximize the properties of specific materials,such as bulk modulus and shear modulus,or to achieve negative Poisson's ratio.Linear material interpolation is used to eliminate the nonlinear challenges and design dependence caused by material penalty.Furthermore,the three-field density representation technique is applied to augment length scales and solid/void characteristics.Through systematic analysis and numerical simulations,the impacts of various initial designs and optimization parameters on the optimization outcomes are investigated.The results demonstrate that the optimized periodic microstructures exhibit extreme performance with clear boundaries.The identification of appropriate optimization parameters is crucial for enhancing the extreme mechanical properties of material microstructures.It can provide valuable guidance for aerospace component design involving material microstructures and metamaterials.
基金supported by the NSFC(12071437)the National Key R&D Program of China(2022YFA1005700).
文摘Combining TT* argument and bilinear interpolation,this paper obtains the Strichartz and smoothing estimates of dispersive semigroup e^(-itP(D)) in weighted L^(2) spaces.Among other things,we recover the results in[1].Moreover,the application of these results to the well-posedness of some equations are shown in the last section.
基金supported by the Major National Science and Technology Infrastructure(No.2208-000000-04-01249628)the Shanghai Science and Technology Commission(No.21DZ1206500)。
文摘We present a hybrid smoothed particle magnetohydrodynamics(SPMHD)code integrating smoothed particle hydrodynamics(SPH)and finite element methods(FEM)to simulate coupled fluid-electromagnetic phenomena.The framework employs SPH for fluid dynamics,addressing large deformations,shocks,and plasma behavior,while FEM resolves electromagnetic fields via Maxwell's equations for magnetic vector and electric scalar potentials,ensuring divergence-free conditions and global current density calculations in conductive region.Operator splitting method couples these modules,enabling real-time integration of magnetic,electric,thermal,and fluid fields.Benchmark tests validate the code against analytical solutions and existing models,including blow-by instability simulations that demonstrate the method's accuracy in capturing fluid-magnetic interactions.Designed for 3D applications,SPMHD offers robust scalability across multiprocessor architectures,establishing it as a versatile tool for plasma physics research.
基金Supported by Science and Technology Innovation Project of China Academy of Chinese Medical Sciences of Study on the Mechanism of Qufeng Jiejing Formula in Regulating Mitogen-activated Protein Kinase Signaling Pathway to Inhibit Phenotypic Transformation of Airway Smooth Muscle Cells in Asthma(No.CI2021A01108)Cultivation Project of The National Natural Science Foundation of China of Xiyuan Hospital,China Academy of Chinese Medical Sciences of Research on the Role of Traditional Chinese Medicines-Qufeng Jiejing in the Proliferation,Migration and Phenotypic Transformation of Airway Smooth Muscle Cells in Asthma(No.XY20-17)。
文摘OBJECTIVE:To explore the role and mechanism of Qufeng Jiejing(祛风解痉,QFJJ)formula in the asthma progression.METHODS:The Bagg Albino/c mice treated with Ovalbumin and AL(OH)3,and airway smooth muscle cells(ASMCs)treated with platelet-derived growth factor(PDGF)-BB to establish a asthma model in vivo and in vitro.The cell morphology was observed with microscope and immunofluorescence staining.The cell viability was assessed with methyl thiazolyl tetrazolium assay.The tumor necrosis factor-αlpha(TNF-α),interleukin-1beta(IL-1β),laminin,fibronectin and collagen IV levels in the ASMCs were detected with corresponding enzyme linked immunosorbent assay kits.Transwell and wound healing assays were conducted to test the cell migration.The TGF-β1,Smad2 and Smad3 levels were measured with Western blot.RESULTS:We found that QFJJ formula treatment dramatically decreased the cell viability,TNF-α,IL-1β,laminin,fibronectin and collagen IV levels in the PDGFBB stimulated ASMCs.Additionally,the protein levels of TGF-β1,Smad2 and Smad3 in the PDGF-BB stimulated ASMCs were prominently depleted after QFJJ formula treatment.Besides,SRI treatment neutralized the role of QFJJ formula in the PDGF-BB stimulated ASMCs.CONCLUSION:QFJJ formula effectively relieved the asthma progression through ameliorate the ASMCs function,which was achieved through suppressing the TGF-β1/Smads signaling pathway.
文摘The evaporation ofmicrometer and millimeter liquid drops,involving a liquid-to-vapor phase transition accompanied by mass and energy transfer through the liquid-vapor interface,is encountered in many natural and industrial processes as well as in numerous engineering applications.Therefore,understanding and predicting the dynamics of evaporating flows have become of primary importance.Recent efforts have been addressed using the method of Smoothed Particle Hydrodynamics(SPH),which has proven to be very efficient in correctly handling the intrinsic complexity introduced by the multiscale nature of the evaporation process.This paper aims to provide an overview of published work on SPH-based simulations related to the evaporation of drops suspended in static and convective environments and impacting on heated solid surfaces.After a brief theoretical account of the main ingredients necessary for the modeling of drop evaporation,the fundamental aspects of SPH are revisited along with the various existing formulations that have been implemented to address the challenges imposed by the physics of evaporating flows.In the following sections,the paper summarizes the results of SPH-based simulations of drop evaporation and ends with a few comments on the limitations of the current state-of-the-art SPHsimulations and future lines of research.
基金supported by the National Natural Science Foundation of China(Grant No.62275235).
文摘We demonstrate a new polarization smoothing(PS)approach utilizing residual stress birefringence in fused silica to create a spatially random polarization control plate(SRPCP),thereby improving target illumination uniformity in inertial confinement fusion(ICF)laser systems.The fundamental operating mechanism and key fabrication techniques for the SRPCP are systematically developed and experimentally validated.The SRPCP converts a linearly polarized 3ω incident laser beam into an output beam with a spatially randomized polarization distribution.When combined with a continuous phase plate,the SRPCP effectively suppresses high-intensity speckles at all spatial frequencies in the focal spot.The proposed PS technique is specifically designed for high-fluence large-aperture laser systems,enabling novel polarization control regimes in laser-driven ICF.
