Analysis and design of linear periodic control systems are closely related to the periodic matrix equations.The biconjugate residual method(BCR for short)have been introduced by Vespucci and Broyden for efficiently so...Analysis and design of linear periodic control systems are closely related to the periodic matrix equations.The biconjugate residual method(BCR for short)have been introduced by Vespucci and Broyden for efficiently solving linear systems Aα=b.The objective of this paper is to provide one new iterative algorithm based on BCR method to find the symmetric periodic solutions of linear periodic matrix equations.This kind of periodic matrix equations has not been dealt with yet.This iterative method is guaranteed to converge in a finite number of steps in the absence of round-off errors.Some numerical results are performed to illustrate the efficiency and feasibility of new method.展开更多
BACKGROUND Thyrotoxic periodic paralysis(TPP)is an endocrine emergency caused by thyrotoxicosis,manifesting mainly as periodic myasthenia and hypokalemia,and posing a serious threat to the patient's health.Fatigue...BACKGROUND Thyrotoxic periodic paralysis(TPP)is an endocrine emergency caused by thyrotoxicosis,manifesting mainly as periodic myasthenia and hypokalemia,and posing a serious threat to the patient's health.Fatigue,strenuous exercise,alcohol abuse,high carbohydrate intake and insulin injections are common triggers of paralysis.This article reports a case of severe TPP induced by insulin injection,elucidates the characteristics and pathogenesis of the disease,analyses the risk factors for triggering TPP,and hopefully provides more clinical data for TPP patients.CASE SUMMARY A 38-year-old Asian man presented to the emergency department with a oneweek history of limb weakness and worsening half-day.His medical history included poorly controlled type 2 diabetes and he had been switched to Aspart50 a week earlier.He was alert and oriented with upper extremity strength grade 3 and lower extremity strength grade 1.Emergency department tests showed hypokalemia of 1.6 mmol/L.The paramedics administered 1.5 g of potassium intravenously,followed by 4.0 g orally.Weakness in the arms and legs improved.He was referred to endocrinology where he was diagnosed with Graves'disease,with suboptimal control and insulin injections possibly causing TPP.We stopped his insulin and he was discharged with a potassium level of 4.0 mmol/L.CONCLUSION Insulin is a trigger for TPP and should be avoided in patients with hyperthyroidism.Early recognition and treatment of TPP is crucial,especially in patients presenting with hypokalemic periodic paralysis.展开更多
The article studies the evolutionary dynamics of two-population two-strategy game models with and without impulses. First, the payment matrix is given and two evolutionary dynamics models are established by adding sto...The article studies the evolutionary dynamics of two-population two-strategy game models with and without impulses. First, the payment matrix is given and two evolutionary dynamics models are established by adding stochastic and impulse. For the stochastic model without impulses, the existence and uniqueness of solution, and the existence of positive periodic solutions are proved, and a sufficient condition for strategy extinction is given. For the stochastic model with impulses, the existence of positive periodic solutions is proved. Numerical results show that noise and impulses directly affect the model, but the periodicity of the model does not change.展开更多
In this paper,we investigate the periodic traveling wave solutions problem for a single population model with advection and distributed delay.By the bifurcation analysis method,we can obtain periodic traveling wave so...In this paper,we investigate the periodic traveling wave solutions problem for a single population model with advection and distributed delay.By the bifurcation analysis method,we can obtain periodic traveling wave solutions for this model under the influence of advection term and distributed delay.The obtained results indicate that weak kernel and strong kernel can both deduce the existence of periodic traveling wave solutions.Finally,we apply the main results in this paper to Logistic model and Nicholson’s blowflies model.展开更多
With the acceleration of urbanization,environmental vibration and noise pollution have become increasingly severe,and traditional vibration and noise reduction technologies are insufficient to meet current vibration c...With the acceleration of urbanization,environmental vibration and noise pollution have become increasingly severe,and traditional vibration and noise reduction technologies are insufficient to meet current vibration control requirements.This study,based on locally resonant theory,designed a novel local resonance periodic block(LRPB).Using the plane wave expansion method(PWEM)and the finite element method(FEM),this study investigated the bandgap characteristics,formation mechanisms,and vibration and acoustic performance of an LRPB under different periodic structures and material selection.The vibration reduction and noise reduction performance of LRPB has been validated through the Qingdao metro project.The research results show that the LRPB is superior to other periodic structures in terms of wide bandgap.Furthermore,configuring soft scatterer material,increasing the unit size,enhancing the material filling rate,and adopting a honeycomb arrangement can effectively reduce bandgap frequency.In structural design,non-high symmetry demonstrates greater advantages.In a study of a subway tunnel,the LRPB demonstrated superior vibration and noise mitigation performance compared to wave impeding block(WIB),thereby demonstrating potential for use in the field of vibration and noise reduction with regard to structures.展开更多
The reservoir landslide undergoes periodic saturation-drying cycles affected by reservoir fluctuation in hydropower project area,leading to the irreversible impact on the landslide materials.Sliding zone is the sheari...The reservoir landslide undergoes periodic saturation-drying cycles affected by reservoir fluctuation in hydropower project area,leading to the irreversible impact on the landslide materials.Sliding zone is the shearing part in formation of landslide and controls the further development of landslide.The mechanical behavior of sliding zone soil under compression is a crucial factor in the stability analysis in landslides.In this paper,the sliding zone soil from a giant landslide in the biggest hydropower project area,Three Gorges Reservoir Area,is taken as the research case.The particlesize distribution of the sliding zone soil from this landslide is studied and fractal dimension is adopted as representation.Periodic saturation-drying is introduced as the affecting factor on sliding zone soil properties.The triaxial compression test is conducted to reveal the mechanical behavior of the soil,including stress-strain behavior,elastic modulus,failure stress and strength parameters.These behavior of sliding zone soils with different fractal dimensions are studied under the effects of periodic saturation-drying cycles.The normalized stress-strain curves are displayed for further calculation.The data considering saturation-drying cycles are obtained and compared with the experimental results.展开更多
The control of adiabatic dynamics is essential for quantum manipulation.We investigate the effects of both periodic modulating field and linear sweeping field on adiabatic dynamics based on a non-reciprocal Landau-Zen...The control of adiabatic dynamics is essential for quantum manipulation.We investigate the effects of both periodic modulating field and linear sweeping field on adiabatic dynamics based on a non-reciprocal Landau-Zener model with periodic modulation.We obtain adiabatic phase diagrams in the(ω,δ)parameter space,where the adiabatic region is bounded by the modulating frequencyωgreater than a critical valueω_(c) and the non-reciprocal parameterδless than one.The results show that the adiabaticity of the system is not sensitive to the modulating amplitude.We find that the critical modulating frequency can be expressed as a power function of the modulating period number or the sweeping rate.Our findings suggest that one can change the adiabatic region or improve the adiabaticity by adjusting the parameters of both the modulating and the sweeping fields,which provides an effective means to flexibly control the adiabatic dynamics of non-reciprocal systems.展开更多
In this paper, a class of discontinuous neutral-type neural networks (NTNNs) with proportional delays is considered. The targets of the paper are to study the problem of periodic solutions and fixed-time (FXT) stabili...In this paper, a class of discontinuous neutral-type neural networks (NTNNs) with proportional delays is considered. The targets of the paper are to study the problem of periodic solutions and fixed-time (FXT) stabilization of the addressed neural networks. In order to complete the targets, based on set-valued map, differential inclusions theory, coincidence theorem and Hölder inequality technique, some new proportional delay-dependent criteria shown by the inequalities are derived. Based on the fact of the existence of solution, further by applying the FXT stability lemmas and equivalent transformation, the zero solution of closed-loop system achieves FXT stabilization and the corresponding settling-times are estimated. Some previous related works on NTNNs are extended. Finally, one typical example is provided to show the effectiveness of the established results.展开更多
Triply periodic minimal surface(TPMS)-based bone implants are an innovative approach in orthopedic implantology,offering customized solutions for bone defect repair and regeneration.This review comprehensively examine...Triply periodic minimal surface(TPMS)-based bone implants are an innovative approach in orthopedic implantology,offering customized solutions for bone defect repair and regeneration.This review comprehensively examines the current research landscape of TPMS-based bone implants,addressing key challenges and proposing future directions.It explores design strategies aimed at optimizing mechanical strength and enhancing biological integration,with a particular emphasis on TPMS structures.These design strategies include graded,hierarchical,and hybrid designs,each contributing to the overall functionality and performance of the implants.This review also highlights state-of-the-art fabrication technologies,particularly advancements in additive manufacturing(AM)techniques for creating metal-based,polymer-based,and ceramic-based bone implants.The ability to precisely control the architecture of TPMS structures using AM techniques is crucial for tailoring the mechanical and biological properties of such implants.Furthermore,this review critically evaluates the biological performance of TPMS implants,focusing on their potential to promote bone ingrowth and regeneration.Key factors,such as mechanical properties,permeability,and biocompatibility,are examined to determine the effectiveness of these implants in clinical applications.By synthesizing existing knowledge and proposing innovative research directions,this review underscores the transformative potential of TPMS-based bone implants in orthopedic surgery.The objective is to improve clinical outcomes and enhance patient care through advanced implant designs and manufacturing techniques.展开更多
Phase classification has a clear guiding significance for the design of high entropy alloys.For mutually exclusive and non-mutually exclusive classifications,the composition descriptors,commonly used physical paramete...Phase classification has a clear guiding significance for the design of high entropy alloys.For mutually exclusive and non-mutually exclusive classifications,the composition descriptors,commonly used physical parameter descriptors,elemental-property descriptors,and descriptors extracted from the periodic table representation(PTR)by the convolutional neural network were collected.Appropriate selection among features with rich information is helpful for phase classification.Based on random forest,the accuracy of the four-label classification and balanced accuracy of the five-label classification were improved to be 0.907 and 0.876,respectively.The roles of the four important features were summarized by interpretability analysis,and a new important feature was found.The model extrapolation ability and the influence of Mo were demonstrated by phase prediction in(CoFeNiMn)_(1-x)Mo_(x).The phase information is helpful for the hardness prediction,the classification results were coupled with the PTR of hardness data,and the prediction error(the root mean square error)was reduced to 56.69.展开更多
The pore structure of porous scaffolds plays a crucial role in bone repair.The prevalent bone implant structure in clinical practice is the traditional cubic structure.However,the traditional cubic structure exhibits ...The pore structure of porous scaffolds plays a crucial role in bone repair.The prevalent bone implant structure in clinical practice is the traditional cubic structure.However,the traditional cubic structure exhibits sharp edges and junctions that are not conducive to cell adhesion or growth.In this study,a double gyroid(DG)Ti6Al4V scaffold based on a triply periodic minimal surface(TPMS)structure was devised,and the osseointegration performance of DG structural scaffolds with varying porosities was investigated.Compression tests revealed that the elastic modulus and compressive strength of DG structural scaffolds were sufficient for orthopedic implants.In vitro cellular experiments demonstrated that the DG structure significantly enhanced cell proliferation,vascularization,and osteogenic differentiation compared to the cubic structure.The DG structure with 55%porosity exhibited the most favorable outcomes.In vivo experiments in rabbits further demonstrated that DG scaffolds could promote neovascularization and bone regeneration and maturation;those with 55%porosity performed best.Comparing the surface area,specific surface area per unit volume,and internal flow distribution characteristics of gyroid and DG structure scaffolds,the latter are more conducive to cell adhesion and growth within scaffolds.This study underscored the potential of DG scaffolds based on the TPMS structure in optimizing the pore structure design of titanium scaffolds,inducing angiogenesis,and advancing the clinical application of titanium scaffolds for repairing bone defects.展开更多
As primary load-bearing components extensively utilized in engineering applications,beam structures necessitate the design of their microstructural configurations to achieve lightweight objectives while satisfying div...As primary load-bearing components extensively utilized in engineering applications,beam structures necessitate the design of their microstructural configurations to achieve lightweight objectives while satisfying diverse mechanical performance requirements.Combining topology optimization with fully coupled homogenization beam theory,we provide a highly efficient design tool to access desirable periodic microstructures for beams.The present optimization framework comprehensively takes into account for key deformation modes,including tension,bending,torsion,and shear deformation,all within a unified formulation.Several numerical results prove that our method can be used to handle kinds of microstructure design for beam-like structures,e.g.,extreme tension(compression)-torsion stiffness,maximization of minimum critical buckling load,and minimization of structural compliance.When optimizing microstructures for macroscopic performance,we emphasize investigating the influence of shear stiffness on the optimized results.The novel chiral beam-like structures are fabricated and tested.The experimental results indicate that the optimized tension(compression)-torsion structure has excellent buffer characteristics,as compared with the traditional square tube.This proposed optimization framework can be further extended to other physical problems of Timoshenko beams.展开更多
Magnesium(Mg)-based materials are promising for lightweight structural applications.However,their widespread adoption is significantly constrained by inherent limitations in mechanical properties.To address this chall...Magnesium(Mg)-based materials are promising for lightweight structural applications.However,their widespread adoption is significantly constrained by inherent limitations in mechanical properties.To address this challenge,this study introduces a novel Mg-based interpenetratingphase composite reinforced with a nickel-titanium(NiTi)scaffold featuring a triply periodic minimal surface(TPMS)configuration.By combining experimental investigations with finite element simulations,we systematically elucidate the dual impact of the scaffold’s unit cell size(a)on manufacturing viability and mechanical enhancement.To compensate for compromised infiltration dynamics induced by decreasing a,a critical permeability threshold of 1×10^(-8) m^(2) is proposed for achieving successful composite fabrication.Mechanically,reducing a strengthens the interaction between the scaffold and matrix:the TPMS-configured NiTi scaffolds improve stress transfer,deflect crack propagation,and facilitate damage delocalization,whereas the Mg matrix preserves structural integrity and enables load redistribution.Consequently,the composites significantly outperform pure Mg,and lowering a leads to more substantial enhancements in compressive strength,energy dissipation,and deformation recoverability.This study offers valuable insight into the design and fabrication of highperformance Mg-based materials for structural and biomedical applications.展开更多
Periodic isolator is well known for its wave filtering characteristic.While in middle and high frequencies,the internal resonances of the periodic isolator are evident especially when damping is small.This study propo...Periodic isolator is well known for its wave filtering characteristic.While in middle and high frequencies,the internal resonances of the periodic isolator are evident especially when damping is small.This study proposes a novel aperiodic vibration isolation for improving the internal resonances control of the periodic isolator.The mechanism of the internal resonances control by the aperiodic isolator is firstly explained.For comparing the internal resonances suppression effect of the aperiodic isolator with the periodic isolator,a dynamic model combing the rigid machine,the isolator,and the flexible plate is derived through multi subsystem modeling method and transfer matrix method,whose accuracy is verified through the finite element method.The influences of the aperiodicity and damping of the isolator on the vibration isolation performance and internal resonances suppression effect are investigated by numerical analysis.The numerical results demonstrate that vibration attenuation performances of the periodic isolator and aperiodic isolator are greatly over than that of the continuous isolator in middle and high frequencies.The aperiodic isolator opens the stop bandgaps comparing with the periodic isolator where the pass bandgaps are periodically existed.The damping of the isolator has the stop bandgap widening effect on both the periodic isolator and the aperiodic isolator.In addition,a parameter optimization algorithm of the aperiodic isolator is presented for improving the internal resonances control effect.It is shown that the vibration peaks within the target frequency band of the aperiodic isolator are effectively reduced after the optimization.Finally,the experiments of the three different vibration isolation systems are conducted for verifying the analysis work.展开更多
The honey badger algorithm(HBA),as a new swarm intelligence(SI)optimization algorithm,has shown certain effectiveness in its applications.Aiming at the problems of unsatisfactory initial population distribution of HBA...The honey badger algorithm(HBA),as a new swarm intelligence(SI)optimization algorithm,has shown certain effectiveness in its applications.Aiming at the problems of unsatisfactory initial population distribution of HBA,poor ability to avoid local optimum,and slow convergence speed,this paper proposes a multi-strategy improved HBA based on periodical mutation and t-distribution perturbation,called MHBA.Firstly,a good point set population initialization is introduced to get a uniform initial population.Secondly,periodic mutation and t-distribution perturbation are successively used to improve the algorithm’s ability to avoid local optimum.Finally,the density factor is improved for balancing exploration and exploitation.By comparing MHBA with HBA and 7 other SIs on 6 benchmark functions,it is evident that the performance of MHBA is far superior to HBA.In addition,by applying MHBA to robot path planning,MHBA can identify the shortest path more quickly and consistently compared with competitors.展开更多
In this paper,we provide new sufficient conditions for the existence of positive periodic solutions for a class of indefinite singular differential equation x′′(t)+a(t)x(t)=h(t)/x^(ρ)(t)+g(t)x^(δ)(t)+e(t),whereρ...In this paper,we provide new sufficient conditions for the existence of positive periodic solutions for a class of indefinite singular differential equation x′′(t)+a(t)x(t)=h(t)/x^(ρ)(t)+g(t)x^(δ)(t)+e(t),whereρandδare two positive constants and 0<δ≤1,h,e∈L^(1)(R/TZ),g∈L^(1)(R/TZ)is positive.Our proofs are based on the fixed point theorems(Schauder’s fixed point theorem and Krasnoselskii-Guo fixed point theorem)and the positivity of the associated Green function.展开更多
In this short paper, we first establish the existence of periodic solutions to parabolic equation in the whole space by using the probability method. Then, the periodicity of some function of stochastic process is als...In this short paper, we first establish the existence of periodic solutions to parabolic equation in the whole space by using the probability method. Then, the periodicity of some function of stochastic process is also studied.展开更多
This paper aims to investigate the tamed Euler method for the random periodic solution of semilinear SDEs with one-sided Lipschitz coefficient.We introduce a novel approach to analyze mean-square error bounds of the n...This paper aims to investigate the tamed Euler method for the random periodic solution of semilinear SDEs with one-sided Lipschitz coefficient.We introduce a novel approach to analyze mean-square error bounds of the novel schemes,without relying on a priori high-order moment bound of the numerical approximation.The expected order-one mean square convergence is attained for the proposed scheme.Moreover,a numerical example is presented to verify our theoretical analysis.展开更多
In this paper,the isogeometric analysis(IGA)method is employed to analyze the oscillation characteristics of functionally graded triply periodic minimal surface(FG-TPMS)curved-doubly shells integrated with magneto-ele...In this paper,the isogeometric analysis(IGA)method is employed to analyze the oscillation characteristics of functionally graded triply periodic minimal surface(FG-TPMS)curved-doubly shells integrated with magneto-electric surface layers(referred to as"FG-TPMS-MEE curved-doubly shells")subjected to low-velocity impact loads.This study presents low-velocity impact load model based on a single springmass(S-M)approach.The FG-TPMS-MEE curved-doubly shells are covered with two magneto-electric surface layers,while the core layer consists of three types:I-graph and Wrapped Package-graph(IWP),Gyroid(G),and Primitive(P),with various graded functions.These types are notable for their exceptional stiffness-to-weight ratios,enabling a wide range of potential applications.The Maxwell equations and electromagnetic boundary conditions are applied to compute the change in electric potentials and magnetic potentials.The equilibrium equations of the shell are derived from a refined higher-order shear deformation theory(HSDT),and the transient responses of the FG-TPMS-MEE curveddoubly shells are subsequently determined using Newmark's direct integration method.These results have applications in structural vibration control and the analysis of structures subjected to impact or explosive loads.Furthermore,this study provides a theoretical prediction of the low-velocity impact load and magneto-electric-elastic effects on the free vibration and transient response of FG-TPMS-MEE curved-doubly shells.展开更多
This paper is devoted to investigating the spreading speed of a time-space periodic epidemic model with vital dynamics and standard incidence in discrete media. We establish the existence of the leftward and rightward...This paper is devoted to investigating the spreading speed of a time-space periodic epidemic model with vital dynamics and standard incidence in discrete media. We establish the existence of the leftward and rightward spreading speeds for the infective individuals, which can be used to estimate how fast the disease spreads. To overcome the difficulty arising from the lack of comparison principle for such time-space periodic nonmonotone systems, our proof is mainly based on constructing a series of scalar time-space periodic equations, establishing the spreading speeds for such auxiliary equations and using comparison methods. It may be the first work to study the spreading speed for time-space periodic non-monotone systems.展开更多
基金Supported by NSFC (No.12371378)NSF of Fujian Province (Nos.2024J01980,2023J01955)。
文摘Analysis and design of linear periodic control systems are closely related to the periodic matrix equations.The biconjugate residual method(BCR for short)have been introduced by Vespucci and Broyden for efficiently solving linear systems Aα=b.The objective of this paper is to provide one new iterative algorithm based on BCR method to find the symmetric periodic solutions of linear periodic matrix equations.This kind of periodic matrix equations has not been dealt with yet.This iterative method is guaranteed to converge in a finite number of steps in the absence of round-off errors.Some numerical results are performed to illustrate the efficiency and feasibility of new method.
文摘BACKGROUND Thyrotoxic periodic paralysis(TPP)is an endocrine emergency caused by thyrotoxicosis,manifesting mainly as periodic myasthenia and hypokalemia,and posing a serious threat to the patient's health.Fatigue,strenuous exercise,alcohol abuse,high carbohydrate intake and insulin injections are common triggers of paralysis.This article reports a case of severe TPP induced by insulin injection,elucidates the characteristics and pathogenesis of the disease,analyses the risk factors for triggering TPP,and hopefully provides more clinical data for TPP patients.CASE SUMMARY A 38-year-old Asian man presented to the emergency department with a oneweek history of limb weakness and worsening half-day.His medical history included poorly controlled type 2 diabetes and he had been switched to Aspart50 a week earlier.He was alert and oriented with upper extremity strength grade 3 and lower extremity strength grade 1.Emergency department tests showed hypokalemia of 1.6 mmol/L.The paramedics administered 1.5 g of potassium intravenously,followed by 4.0 g orally.Weakness in the arms and legs improved.He was referred to endocrinology where he was diagnosed with Graves'disease,with suboptimal control and insulin injections possibly causing TPP.We stopped his insulin and he was discharged with a potassium level of 4.0 mmol/L.CONCLUSION Insulin is a trigger for TPP and should be avoided in patients with hyperthyroidism.Early recognition and treatment of TPP is crucial,especially in patients presenting with hypokalemic periodic paralysis.
基金Supported by the National Natural Science Foundation of China(10671182)。
文摘The article studies the evolutionary dynamics of two-population two-strategy game models with and without impulses. First, the payment matrix is given and two evolutionary dynamics models are established by adding stochastic and impulse. For the stochastic model without impulses, the existence and uniqueness of solution, and the existence of positive periodic solutions are proved, and a sufficient condition for strategy extinction is given. For the stochastic model with impulses, the existence of positive periodic solutions is proved. Numerical results show that noise and impulses directly affect the model, but the periodicity of the model does not change.
基金Supported by the National Natural Science Foundation of China(12261050)Science and Technology Project of Department of Education of Jiangxi Province(GJJ2201612 and GJJ211027)Natural Science Foundation of Jiangxi Province of China(20212BAB202021)。
文摘In this paper,we investigate the periodic traveling wave solutions problem for a single population model with advection and distributed delay.By the bifurcation analysis method,we can obtain periodic traveling wave solutions for this model under the influence of advection term and distributed delay.The obtained results indicate that weak kernel and strong kernel can both deduce the existence of periodic traveling wave solutions.Finally,we apply the main results in this paper to Logistic model and Nicholson’s blowflies model.
基金Natural Science Foundation of China under Grant No.42277130Natural Science Foundation of Shandong Province under Grant No.ZR2021ME144。
文摘With the acceleration of urbanization,environmental vibration and noise pollution have become increasingly severe,and traditional vibration and noise reduction technologies are insufficient to meet current vibration control requirements.This study,based on locally resonant theory,designed a novel local resonance periodic block(LRPB).Using the plane wave expansion method(PWEM)and the finite element method(FEM),this study investigated the bandgap characteristics,formation mechanisms,and vibration and acoustic performance of an LRPB under different periodic structures and material selection.The vibration reduction and noise reduction performance of LRPB has been validated through the Qingdao metro project.The research results show that the LRPB is superior to other periodic structures in terms of wide bandgap.Furthermore,configuring soft scatterer material,increasing the unit size,enhancing the material filling rate,and adopting a honeycomb arrangement can effectively reduce bandgap frequency.In structural design,non-high symmetry demonstrates greater advantages.In a study of a subway tunnel,the LRPB demonstrated superior vibration and noise mitigation performance compared to wave impeding block(WIB),thereby demonstrating potential for use in the field of vibration and noise reduction with regard to structures.
基金financially supported by the National Natural Science Foundation of China(Nos.42107194,42090054,42377182)the Fundamental Research Funds for the Central Universities(No.CUGL190810)the Open Foundation of Engineering Research Center of Rock-Soil Drilling&Excavation and Protection,Ministry of Education(No.201802)。
文摘The reservoir landslide undergoes periodic saturation-drying cycles affected by reservoir fluctuation in hydropower project area,leading to the irreversible impact on the landslide materials.Sliding zone is the shearing part in formation of landslide and controls the further development of landslide.The mechanical behavior of sliding zone soil under compression is a crucial factor in the stability analysis in landslides.In this paper,the sliding zone soil from a giant landslide in the biggest hydropower project area,Three Gorges Reservoir Area,is taken as the research case.The particlesize distribution of the sliding zone soil from this landslide is studied and fractal dimension is adopted as representation.Periodic saturation-drying is introduced as the affecting factor on sliding zone soil properties.The triaxial compression test is conducted to reveal the mechanical behavior of the soil,including stress-strain behavior,elastic modulus,failure stress and strength parameters.These behavior of sliding zone soils with different fractal dimensions are studied under the effects of periodic saturation-drying cycles.The normalized stress-strain curves are displayed for further calculation.The data considering saturation-drying cycles are obtained and compared with the experimental results.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12375019 and 11974273)。
文摘The control of adiabatic dynamics is essential for quantum manipulation.We investigate the effects of both periodic modulating field and linear sweeping field on adiabatic dynamics based on a non-reciprocal Landau-Zener model with periodic modulation.We obtain adiabatic phase diagrams in the(ω,δ)parameter space,where the adiabatic region is bounded by the modulating frequencyωgreater than a critical valueω_(c) and the non-reciprocal parameterδless than one.The results show that the adiabaticity of the system is not sensitive to the modulating amplitude.We find that the critical modulating frequency can be expressed as a power function of the modulating period number or the sweeping rate.Our findings suggest that one can change the adiabatic region or improve the adiabaticity by adjusting the parameters of both the modulating and the sweeping fields,which provides an effective means to flexibly control the adiabatic dynamics of non-reciprocal systems.
基金supported by Social Science Fund of Hunan province(Grant No.22JD074)the Research Foundation of Education Bureau of Hunan province(Grant No.22B0912).
文摘In this paper, a class of discontinuous neutral-type neural networks (NTNNs) with proportional delays is considered. The targets of the paper are to study the problem of periodic solutions and fixed-time (FXT) stabilization of the addressed neural networks. In order to complete the targets, based on set-valued map, differential inclusions theory, coincidence theorem and Hölder inequality technique, some new proportional delay-dependent criteria shown by the inequalities are derived. Based on the fact of the existence of solution, further by applying the FXT stability lemmas and equivalent transformation, the zero solution of closed-loop system achieves FXT stabilization and the corresponding settling-times are estimated. Some previous related works on NTNNs are extended. Finally, one typical example is provided to show the effectiveness of the established results.
基金funded by the National Natural Science Foundation of China(No.52275343)the Natural Science Foundation of Zhejiang Province(No.LY23E050003)+1 种基金Ningbo Youth Science and Technology Innovation Leading Talent Project(No.2023QL021)Smart Medicine and Engineering Interdisciplinary Innovation Project of Ningbo University(No.ZHYG001).
文摘Triply periodic minimal surface(TPMS)-based bone implants are an innovative approach in orthopedic implantology,offering customized solutions for bone defect repair and regeneration.This review comprehensively examines the current research landscape of TPMS-based bone implants,addressing key challenges and proposing future directions.It explores design strategies aimed at optimizing mechanical strength and enhancing biological integration,with a particular emphasis on TPMS structures.These design strategies include graded,hierarchical,and hybrid designs,each contributing to the overall functionality and performance of the implants.This review also highlights state-of-the-art fabrication technologies,particularly advancements in additive manufacturing(AM)techniques for creating metal-based,polymer-based,and ceramic-based bone implants.The ability to precisely control the architecture of TPMS structures using AM techniques is crucial for tailoring the mechanical and biological properties of such implants.Furthermore,this review critically evaluates the biological performance of TPMS implants,focusing on their potential to promote bone ingrowth and regeneration.Key factors,such as mechanical properties,permeability,and biocompatibility,are examined to determine the effectiveness of these implants in clinical applications.By synthesizing existing knowledge and proposing innovative research directions,this review underscores the transformative potential of TPMS-based bone implants in orthopedic surgery.The objective is to improve clinical outcomes and enhance patient care through advanced implant designs and manufacturing techniques.
基金supported by the National Natural Science Foundation of China(Nos.51671075,51971086)the Natural Science Foundation of Heilongjiang Province,China(No.LH2022E081)。
文摘Phase classification has a clear guiding significance for the design of high entropy alloys.For mutually exclusive and non-mutually exclusive classifications,the composition descriptors,commonly used physical parameter descriptors,elemental-property descriptors,and descriptors extracted from the periodic table representation(PTR)by the convolutional neural network were collected.Appropriate selection among features with rich information is helpful for phase classification.Based on random forest,the accuracy of the four-label classification and balanced accuracy of the five-label classification were improved to be 0.907 and 0.876,respectively.The roles of the four important features were summarized by interpretability analysis,and a new important feature was found.The model extrapolation ability and the influence of Mo were demonstrated by phase prediction in(CoFeNiMn)_(1-x)Mo_(x).The phase information is helpful for the hardness prediction,the classification results were coupled with the PTR of hardness data,and the prediction error(the root mean square error)was reduced to 56.69.
基金supported bythe National Natural Science Foundation of China(Nos.U23A20523,82272504,and 82072456)the Department of Science and Technology of Jilin Province,China(Nos.20210101439JC,20210101321JC,20220204119YY,202201ZYTS131,202201ZYTS129,20230204114YY,YDZJ202201ZYTS505,and YDZJ202301ZYTS076)+4 种基金the Special Program for Science and Technology Personnel of Changchun(No.ZKICKJJ2023015)the Key Training Plan for Outstanding Youth of Jilin University(No.419070623036)the Research Fund of the First Hospital of Jilin University(No.2021-zl-01)the Graduate Innovation Fund of Jilin University(No.2024CX125)the Foun-dation of National Center for Translational Medicine(Shanghai)SHU Branch,China(No.SUITM-202405).
文摘The pore structure of porous scaffolds plays a crucial role in bone repair.The prevalent bone implant structure in clinical practice is the traditional cubic structure.However,the traditional cubic structure exhibits sharp edges and junctions that are not conducive to cell adhesion or growth.In this study,a double gyroid(DG)Ti6Al4V scaffold based on a triply periodic minimal surface(TPMS)structure was devised,and the osseointegration performance of DG structural scaffolds with varying porosities was investigated.Compression tests revealed that the elastic modulus and compressive strength of DG structural scaffolds were sufficient for orthopedic implants.In vitro cellular experiments demonstrated that the DG structure significantly enhanced cell proliferation,vascularization,and osteogenic differentiation compared to the cubic structure.The DG structure with 55%porosity exhibited the most favorable outcomes.In vivo experiments in rabbits further demonstrated that DG scaffolds could promote neovascularization and bone regeneration and maturation;those with 55%porosity performed best.Comparing the surface area,specific surface area per unit volume,and internal flow distribution characteristics of gyroid and DG structure scaffolds,the latter are more conducive to cell adhesion and growth within scaffolds.This study underscored the potential of DG scaffolds based on the TPMS structure in optimizing the pore structure design of titanium scaffolds,inducing angiogenesis,and advancing the clinical application of titanium scaffolds for repairing bone defects.
基金supported by the National Natural Science Foundation of China(grant number 11902015)the Open Fund of Deceleration and Landing Laboratory of the Fifth Academy of Aerospace Science and Technology Group(grant number EDL19092138)the Ministry of Education Chunhui Plan(HZKY20220014).
文摘As primary load-bearing components extensively utilized in engineering applications,beam structures necessitate the design of their microstructural configurations to achieve lightweight objectives while satisfying diverse mechanical performance requirements.Combining topology optimization with fully coupled homogenization beam theory,we provide a highly efficient design tool to access desirable periodic microstructures for beams.The present optimization framework comprehensively takes into account for key deformation modes,including tension,bending,torsion,and shear deformation,all within a unified formulation.Several numerical results prove that our method can be used to handle kinds of microstructure design for beam-like structures,e.g.,extreme tension(compression)-torsion stiffness,maximization of minimum critical buckling load,and minimization of structural compliance.When optimizing microstructures for macroscopic performance,we emphasize investigating the influence of shear stiffness on the optimized results.The novel chiral beam-like structures are fabricated and tested.The experimental results indicate that the optimized tension(compression)-torsion structure has excellent buffer characteristics,as compared with the traditional square tube.This proposed optimization framework can be further extended to other physical problems of Timoshenko beams.
基金supported by the Mainland-Hong Kong Joint Funding Scheme(MHKJFS)(Project No:MHP/040/22)RGC Theme-based Research Scheme AoE/M-402/20+1 种基金National Natural Science Foundation of China/Hong Kong Research Grants Council Joint Research Scheme(Project No:N_CityU151/23)Hong Kong Innovation and Technology Commission via the Hong Kong Branch of National Precious Metals Materials Engineering Research Center.
文摘Magnesium(Mg)-based materials are promising for lightweight structural applications.However,their widespread adoption is significantly constrained by inherent limitations in mechanical properties.To address this challenge,this study introduces a novel Mg-based interpenetratingphase composite reinforced with a nickel-titanium(NiTi)scaffold featuring a triply periodic minimal surface(TPMS)configuration.By combining experimental investigations with finite element simulations,we systematically elucidate the dual impact of the scaffold’s unit cell size(a)on manufacturing viability and mechanical enhancement.To compensate for compromised infiltration dynamics induced by decreasing a,a critical permeability threshold of 1×10^(-8) m^(2) is proposed for achieving successful composite fabrication.Mechanically,reducing a strengthens the interaction between the scaffold and matrix:the TPMS-configured NiTi scaffolds improve stress transfer,deflect crack propagation,and facilitate damage delocalization,whereas the Mg matrix preserves structural integrity and enables load redistribution.Consequently,the composites significantly outperform pure Mg,and lowering a leads to more substantial enhancements in compressive strength,energy dissipation,and deformation recoverability.This study offers valuable insight into the design and fabrication of highperformance Mg-based materials for structural and biomedical applications.
基金supported by the National Key Research and Development Plan of China (Grant No.2023YFB3406302)Guangdong Basic and Applied Basic Research Foundation (Grant No.2024A1515011126)the Key Research and Development Plan of Shanxi (Grant No.2024GH-ZDXM-29)。
文摘Periodic isolator is well known for its wave filtering characteristic.While in middle and high frequencies,the internal resonances of the periodic isolator are evident especially when damping is small.This study proposes a novel aperiodic vibration isolation for improving the internal resonances control of the periodic isolator.The mechanism of the internal resonances control by the aperiodic isolator is firstly explained.For comparing the internal resonances suppression effect of the aperiodic isolator with the periodic isolator,a dynamic model combing the rigid machine,the isolator,and the flexible plate is derived through multi subsystem modeling method and transfer matrix method,whose accuracy is verified through the finite element method.The influences of the aperiodicity and damping of the isolator on the vibration isolation performance and internal resonances suppression effect are investigated by numerical analysis.The numerical results demonstrate that vibration attenuation performances of the periodic isolator and aperiodic isolator are greatly over than that of the continuous isolator in middle and high frequencies.The aperiodic isolator opens the stop bandgaps comparing with the periodic isolator where the pass bandgaps are periodically existed.The damping of the isolator has the stop bandgap widening effect on both the periodic isolator and the aperiodic isolator.In addition,a parameter optimization algorithm of the aperiodic isolator is presented for improving the internal resonances control effect.It is shown that the vibration peaks within the target frequency band of the aperiodic isolator are effectively reduced after the optimization.Finally,the experiments of the three different vibration isolation systems are conducted for verifying the analysis work.
基金Supported by the National Key Research and Development Program of China(No.2022ZD0119001)。
文摘The honey badger algorithm(HBA),as a new swarm intelligence(SI)optimization algorithm,has shown certain effectiveness in its applications.Aiming at the problems of unsatisfactory initial population distribution of HBA,poor ability to avoid local optimum,and slow convergence speed,this paper proposes a multi-strategy improved HBA based on periodical mutation and t-distribution perturbation,called MHBA.Firstly,a good point set population initialization is introduced to get a uniform initial population.Secondly,periodic mutation and t-distribution perturbation are successively used to improve the algorithm’s ability to avoid local optimum.Finally,the density factor is improved for balancing exploration and exploitation.By comparing MHBA with HBA and 7 other SIs on 6 benchmark functions,it is evident that the performance of MHBA is far superior to HBA.In addition,by applying MHBA to robot path planning,MHBA can identify the shortest path more quickly and consistently compared with competitors.
基金supported by the Technological Innovation Talents in Universities and Colleges in Henan Province(No.21HASTIT025)the Natural Science Foundation of Henan Province(No.222300420449)the Innovative Research Team of Henan Polytechnic University(No.T2022-7)。
文摘In this paper,we provide new sufficient conditions for the existence of positive periodic solutions for a class of indefinite singular differential equation x′′(t)+a(t)x(t)=h(t)/x^(ρ)(t)+g(t)x^(δ)(t)+e(t),whereρandδare two positive constants and 0<δ≤1,h,e∈L^(1)(R/TZ),g∈L^(1)(R/TZ)is positive.Our proofs are based on the fixed point theorems(Schauder’s fixed point theorem and Krasnoselskii-Guo fixed point theorem)and the positivity of the associated Green function.
基金Supported by the National Natural Science Foundation of China(12171247)。
文摘In this short paper, we first establish the existence of periodic solutions to parabolic equation in the whole space by using the probability method. Then, the periodicity of some function of stochastic process is also studied.
基金supported by the National Natural Science Foundation of China(Nos.12471394,12371417)Natural Science Foundation of Changsha(No.kq2502101)。
文摘This paper aims to investigate the tamed Euler method for the random periodic solution of semilinear SDEs with one-sided Lipschitz coefficient.We introduce a novel approach to analyze mean-square error bounds of the novel schemes,without relying on a priori high-order moment bound of the numerical approximation.The expected order-one mean square convergence is attained for the proposed scheme.Moreover,a numerical example is presented to verify our theoretical analysis.
文摘In this paper,the isogeometric analysis(IGA)method is employed to analyze the oscillation characteristics of functionally graded triply periodic minimal surface(FG-TPMS)curved-doubly shells integrated with magneto-electric surface layers(referred to as"FG-TPMS-MEE curved-doubly shells")subjected to low-velocity impact loads.This study presents low-velocity impact load model based on a single springmass(S-M)approach.The FG-TPMS-MEE curved-doubly shells are covered with two magneto-electric surface layers,while the core layer consists of three types:I-graph and Wrapped Package-graph(IWP),Gyroid(G),and Primitive(P),with various graded functions.These types are notable for their exceptional stiffness-to-weight ratios,enabling a wide range of potential applications.The Maxwell equations and electromagnetic boundary conditions are applied to compute the change in electric potentials and magnetic potentials.The equilibrium equations of the shell are derived from a refined higher-order shear deformation theory(HSDT),and the transient responses of the FG-TPMS-MEE curveddoubly shells are subsequently determined using Newmark's direct integration method.These results have applications in structural vibration control and the analysis of structures subjected to impact or explosive loads.Furthermore,this study provides a theoretical prediction of the low-velocity impact load and magneto-electric-elastic effects on the free vibration and transient response of FG-TPMS-MEE curved-doubly shells.
基金supported by the Natural Science Basic Research Program of Shanxi(Grant No.2024JC-YBMS-025)the Innovation Capability Support Program of Shanxi(Grant No.2024RS-CXTD-88)。
文摘This paper is devoted to investigating the spreading speed of a time-space periodic epidemic model with vital dynamics and standard incidence in discrete media. We establish the existence of the leftward and rightward spreading speeds for the infective individuals, which can be used to estimate how fast the disease spreads. To overcome the difficulty arising from the lack of comparison principle for such time-space periodic nonmonotone systems, our proof is mainly based on constructing a series of scalar time-space periodic equations, establishing the spreading speeds for such auxiliary equations and using comparison methods. It may be the first work to study the spreading speed for time-space periodic non-monotone systems.
