Although predictor-corrector methods have been extensively applied,they might not meet the requirements of practical applications and engineering tasks,particularly when high accuracy and efficiency are necessary.A no...Although predictor-corrector methods have been extensively applied,they might not meet the requirements of practical applications and engineering tasks,particularly when high accuracy and efficiency are necessary.A novel class of correctors based on feedback-accelerated Picard iteration(FAPI)is proposed to further enhance computational performance.With optimal feedback terms that do not require inversion of matrices,significantly faster convergence speed and higher numerical accuracy are achieved by these correctors compared with their counterparts;however,the computational complexities are comparably low.These advantages enable nonlinear engineering problems to be solved quickly and accurately,even with rough initial guesses from elementary predictors.The proposed method offers flexibility,enabling the use of the generated correctors for either bulk processing of collocation nodes in a domain or successive corrections of a single node in a finite difference approach.In our method,the functional formulas of FAPI are discretized into numerical forms using the collocation approach.These collocated iteration formulas can directly solve nonlinear problems,but they may require significant computational resources because of the manipulation of high-dimensionalmatrices.To address this,the collocated iteration formulas are further converted into finite difference forms,enabling the design of lightweight predictor-corrector algorithms for real-time computation.The generality of the proposed method is illustrated by deriving new correctors for three commonly employed finite-difference approaches:the modified Euler approach,the Adams-Bashforth-Moulton approach,and the implicit Runge-Kutta approach.Subsequently,the updated approaches are tested in solving strongly nonlinear problems,including the Matthieu equation,the Duffing equation,and the low-earth-orbit tracking problem.The numerical findings confirm the computational accuracy and efficiency of the derived predictor-corrector algorithms.展开更多
This paper compares the variational iteration method(VIM),the Adomian decomposition method(ADM)and the Picard iteration method(PIM)for solving a system of first o rder n onlinear o rdinary d ifferential e quations(ODE...This paper compares the variational iteration method(VIM),the Adomian decomposition method(ADM)and the Picard iteration method(PIM)for solving a system of first o rder n onlinear o rdinary d ifferential e quations(ODEs).A unification of the concepts underlying these three methods is attempted by considering a very general iterative algorithm for VIM.It is found that all the three methods can be regarded as special cases of using a very general matrix of Lagrange multipliers in the iterative algorithm of VIM.The global variational iteration method is briefly reviewed,and further recast into a Local VIM,which is much more convenient and capable of predicting long term complex dynamic responses of nonlinear systems even if they are chaotic.展开更多
As a non-toxic,highly reactive biomass material,gelatin is wildly used as the component of biomass-based adhesive.However,like most aqueous adhesives,gelatin-based adhesives suffer from long solidifying time or high s...As a non-toxic,highly reactive biomass material,gelatin is wildly used as the component of biomass-based adhesive.However,like most aqueous adhesives,gelatin-based adhesives suffer from long solidifying time or high solidifying temperature due to the low volatility of water,which highly limits the application potential of gelatinbased adhesives.Inspired by the fast adhesion of marine organisms through the formation of chemical crosslinks,herein,a kind of low temperature curable eco-friendly gelatin-based adhesive with good adhesive properties and fast curing at low temperature is developed by introducing clicking chemical Diels-Alder(DA)reaction between blocked waterborne polyurethane(MWPU)and gelatin.The furfuryl glycidyl ether(FGE)and 4-Maleimidophenol(4-HPM)for the DA reaction are grafted on gelatin,and the end-capping of MWPU,respectively.With the addition of MWPU and FGE,the cross-linking degree of gelatin increased,and the adhesion properties of the adhesive were improved.The shear strength and T-peel strength of the modified adhesive reached 0.95 MPa and 1.42 N/mm,respectively,after the curing time of 8 min at 40℃,which can meet the application requirements as adhesive for bio-medical use.展开更多
Wound abnormalities such as secondary wound laceration and inflammation are common postoperative health hazards during clinical procedures.The continuous treatment,healing induction,and real-time visualization of woun...Wound abnormalities such as secondary wound laceration and inflammation are common postoperative health hazards during clinical procedures.The continuous treatment,healing induction,and real-time visualization of wound status and complications,including wound re-tearing,inflammation,and morphology,are key focal points for comprehensive healthcare.Herein,an on-demand quadruple energy dissipative strategy was proposed for the nanoengineering of a physically and chemically synergistic double-layer gelatin-based bio-adhesive(DLGel)by combining a multi-network adhesive layer and a versatile electroactive energy dissipative layer based on contrivable interlocking micro-pillar arrays and crosslinked polymer chains.The subtly multiple energy dissipation designs enable DLGel with robust adhesive strength to omnipotently wet and dynamic tissue,providing a basis for reliable wound closure.DLGel achieves comprehensive wound-healing induction through electrical stimulation and possesses reversible underwater light/thermal adhesion,excellent hemostatic performance,outstanding antimicrobial properties,and self-repair capability.Furthermore,a novel deep-learning strategy is creatively established to respond to mechanical deformation due to wound anomalies.This strategy translates biological information into visual graphics,providing real-time early warning and assessment of postoperative wound-abnormality/-morphology,such as laceration,inflammation,and necrosis.Therefore,DLGel and its associated signal collection and processing protocol enable the integration of reliable wound closure,wound healing,and real-time postoperative wound-status warning and assessment within the unobservable and undetectable“black box”regions in a context of non-clinical comprehensive therapy.展开更多
For over half a century,numerical integration methods based on finite difference,such as the Runge-Kutta method and the Euler method,have been popular and widely used for solving orbit dynamic problems.In general,a sm...For over half a century,numerical integration methods based on finite difference,such as the Runge-Kutta method and the Euler method,have been popular and widely used for solving orbit dynamic problems.In general,a small integration step size is always required to suppress the increase of the accumulated computation error,which leads to a relatively slow computation speed.Recently,a collocation iteration method,approximating the solutions of orbit dynamic problems iteratively,has been developed.This method achieves high computation accuracy with extremely large step size.Although efficient,the collocation iteration method suffers from two limitations:(A)the computational error limit of the approximate solution is not clear;(B)extensive trials and errors are always required in tuning parameters.To overcome these problems,the influence mechanism of how the dynamic problems and parameters affect the error limit of the collocation iteration method is explored.On this basis,a parameter adjustment method known as the“polishing method”is proposed to improve the computation speed.The method proposed is demonstrated in three typical orbit dynamic problems in aerospace engineering:a low Earth orbit propagation problem,a Molniya orbit propagation problem,and a geostationary orbit propagation problem.Numerical simulations show that the proposed polishing method is faster and more accurate than the finite-difference-based method and the most advanced collocation iteration method.展开更多
Currently,due to improvements in living standards,people are paying more attention to all-around disease prevention and health care.Self-powered implantable“tissue batteries”integrated with electrochemical materials...Currently,due to improvements in living standards,people are paying more attention to all-around disease prevention and health care.Self-powered implantable“tissue batteries”integrated with electrochemical materials are essential for disease prevention,diagnosis,treatment,postoperative therapy,and healthcare applications.We propose and define new concepts of“tissue batteries”-self-powered tissue batteries(SPTBs)-are flexible self-powered implantable systems or platforms based on electroactive biomaterials,acting at the interface of biological tissue.Based on the electrical phenomenon of living organisms in life activities,there has been an increased attention to SPTBs for tissue repair promotion.SPTBs take advantages of both the preeminent biocompatibility of biomaterials and the promotion of time-honored electrical stimulation therapy for tissue recovery,which are very promising for human illness treatment.However,studies on clinical applications of SPTBs are impeded by a lack of comprehensive cognitive assessment of SPTBs.Herein,SPTBs for life and health applications are comprehensively reviewed.First,electrochemical materials and their across-the-board applications for several types of SPTBs are introduced and compared with regard to disease prevention,diagnosis,precision therapy,and personalized health monitoring.Then,the potential mechanisms for SPTBs for tissue repair promotion are discussed.Finally,the prospective challenges are summarized and recommendations for future research are provided.This review elucidates on the significance and versatility of SPTBs for various medical applications.展开更多
Nowadays, diverse leather usage conditions and increasing demands from consumers challenge the leather industry. Traditional leather manufacturing is facing long-term challenges, including low-value threshold, confine...Nowadays, diverse leather usage conditions and increasing demands from consumers challenge the leather industry. Traditional leather manufacturing is facing long-term challenges, including low-value threshold, confined applica-tion fields, and environmental issues. Leather inherits all the biomimetic properties of natural skin such as flexibility, sanitation, cold resistance, biocompatibility, biodegradability, and other cross-domain functions, achieving unre-mitting attention in multi-functional bio-based materials. Series of researches have been devoted to creating and developing leather-based flexible multi-functional bio-materials, including antibacterial leather, conductive leather, flame-retardant leather, self-cleaning leather, aromatic leather, and electromagnetic shielding leather. In this review, we provide a comprehensive overview of the commonly used leather-based functional materials. Furthermore, the possible challenges for the development of functional leathers are proposed, and expected development directions of leather-based functional materials are discussed. This review may promote and inspire the emerging preparation and applications of leather for flexible functional bio-based materials.展开更多
With the characteristics of controllable charge and environmental friendliness,amphoteric polymers can be used in post-tanning process to solve the problems that arise during leather making and are caused by the low a...With the characteristics of controllable charge and environmental friendliness,amphoteric polymers can be used in post-tanning process to solve the problems that arise during leather making and are caused by the low absorption rate of single-charge chemicals,incompatibility with new tanning methods,and complex operation process.In this review,the structure,performance,and preparation of amphoteric polymers are reported.Then,the charge change of collagen during different tanning and pH treatments is introduced.Finally,the application and development of amphoteric polymers during the post-tanning process of leather making are discussed.This review has certain guiding significance to the preparation and application of amphoteric polymers for tanning system.展开更多
基金work is supported by the Fundamental Research Funds for the Central Universities(No.3102019HTQD014)of Northwestern Polytechnical UniversityFunding of National Key Laboratory of Astronautical Flight DynamicsYoung Talent Support Project of Shaanxi State.
文摘Although predictor-corrector methods have been extensively applied,they might not meet the requirements of practical applications and engineering tasks,particularly when high accuracy and efficiency are necessary.A novel class of correctors based on feedback-accelerated Picard iteration(FAPI)is proposed to further enhance computational performance.With optimal feedback terms that do not require inversion of matrices,significantly faster convergence speed and higher numerical accuracy are achieved by these correctors compared with their counterparts;however,the computational complexities are comparably low.These advantages enable nonlinear engineering problems to be solved quickly and accurately,even with rough initial guesses from elementary predictors.The proposed method offers flexibility,enabling the use of the generated correctors for either bulk processing of collocation nodes in a domain or successive corrections of a single node in a finite difference approach.In our method,the functional formulas of FAPI are discretized into numerical forms using the collocation approach.These collocated iteration formulas can directly solve nonlinear problems,but they may require significant computational resources because of the manipulation of high-dimensionalmatrices.To address this,the collocated iteration formulas are further converted into finite difference forms,enabling the design of lightweight predictor-corrector algorithms for real-time computation.The generality of the proposed method is illustrated by deriving new correctors for three commonly employed finite-difference approaches:the modified Euler approach,the Adams-Bashforth-Moulton approach,and the implicit Runge-Kutta approach.Subsequently,the updated approaches are tested in solving strongly nonlinear problems,including the Matthieu equation,the Duffing equation,and the low-earth-orbit tracking problem.The numerical findings confirm the computational accuracy and efficiency of the derived predictor-corrector algorithms.
文摘This paper compares the variational iteration method(VIM),the Adomian decomposition method(ADM)and the Picard iteration method(PIM)for solving a system of first o rder n onlinear o rdinary d ifferential e quations(ODEs).A unification of the concepts underlying these three methods is attempted by considering a very general iterative algorithm for VIM.It is found that all the three methods can be regarded as special cases of using a very general matrix of Lagrange multipliers in the iterative algorithm of VIM.The global variational iteration method is briefly reviewed,and further recast into a Local VIM,which is much more convenient and capable of predicting long term complex dynamic responses of nonlinear systems even if they are chaotic.
基金the financial support from the National Natural Science Foundation of China(22002079,2207081675,and 22108165)the Natural Science Basic Research Program of Shaanxi(Program No.2021JQ-548).
文摘As a non-toxic,highly reactive biomass material,gelatin is wildly used as the component of biomass-based adhesive.However,like most aqueous adhesives,gelatin-based adhesives suffer from long solidifying time or high solidifying temperature due to the low volatility of water,which highly limits the application potential of gelatinbased adhesives.Inspired by the fast adhesion of marine organisms through the formation of chemical crosslinks,herein,a kind of low temperature curable eco-friendly gelatin-based adhesive with good adhesive properties and fast curing at low temperature is developed by introducing clicking chemical Diels-Alder(DA)reaction between blocked waterborne polyurethane(MWPU)and gelatin.The furfuryl glycidyl ether(FGE)and 4-Maleimidophenol(4-HPM)for the DA reaction are grafted on gelatin,and the end-capping of MWPU,respectively.With the addition of MWPU and FGE,the cross-linking degree of gelatin increased,and the adhesion properties of the adhesive were improved.The shear strength and T-peel strength of the modified adhesive reached 0.95 MPa and 1.42 N/mm,respectively,after the curing time of 8 min at 40℃,which can meet the application requirements as adhesive for bio-medical use.
基金supported by Fellowship of China Postdoctoral Science Foundation(No.2023M732159)the National Natural Science Foundation of China(Nos.22308209 ,2207081675)+1 种基金Key R&D Program of Shaanxi Province(No.2022GY-272)Young Talent Support Program Project of Shaanxi University Science and Technology Association(No.20200424).
文摘Wound abnormalities such as secondary wound laceration and inflammation are common postoperative health hazards during clinical procedures.The continuous treatment,healing induction,and real-time visualization of wound status and complications,including wound re-tearing,inflammation,and morphology,are key focal points for comprehensive healthcare.Herein,an on-demand quadruple energy dissipative strategy was proposed for the nanoengineering of a physically and chemically synergistic double-layer gelatin-based bio-adhesive(DLGel)by combining a multi-network adhesive layer and a versatile electroactive energy dissipative layer based on contrivable interlocking micro-pillar arrays and crosslinked polymer chains.The subtly multiple energy dissipation designs enable DLGel with robust adhesive strength to omnipotently wet and dynamic tissue,providing a basis for reliable wound closure.DLGel achieves comprehensive wound-healing induction through electrical stimulation and possesses reversible underwater light/thermal adhesion,excellent hemostatic performance,outstanding antimicrobial properties,and self-repair capability.Furthermore,a novel deep-learning strategy is creatively established to respond to mechanical deformation due to wound anomalies.This strategy translates biological information into visual graphics,providing real-time early warning and assessment of postoperative wound-abnormality/-morphology,such as laceration,inflammation,and necrosis.Therefore,DLGel and its associated signal collection and processing protocol enable the integration of reliable wound closure,wound healing,and real-time postoperative wound-status warning and assessment within the unobservable and undetectable“black box”regions in a context of non-clinical comprehensive therapy.
基金This study was co-supported by the National Key Research and Development Program of China(No.2021YFA0717100)the National Natural Science Foundation of China(Nos.12072270,U2013206).
文摘For over half a century,numerical integration methods based on finite difference,such as the Runge-Kutta method and the Euler method,have been popular and widely used for solving orbit dynamic problems.In general,a small integration step size is always required to suppress the increase of the accumulated computation error,which leads to a relatively slow computation speed.Recently,a collocation iteration method,approximating the solutions of orbit dynamic problems iteratively,has been developed.This method achieves high computation accuracy with extremely large step size.Although efficient,the collocation iteration method suffers from two limitations:(A)the computational error limit of the approximate solution is not clear;(B)extensive trials and errors are always required in tuning parameters.To overcome these problems,the influence mechanism of how the dynamic problems and parameters affect the error limit of the collocation iteration method is explored.On this basis,a parameter adjustment method known as the“polishing method”is proposed to improve the computation speed.The method proposed is demonstrated in three typical orbit dynamic problems in aerospace engineering:a low Earth orbit propagation problem,a Molniya orbit propagation problem,and a geostationary orbit propagation problem.Numerical simulations show that the proposed polishing method is faster and more accurate than the finite-difference-based method and the most advanced collocation iteration method.
基金the National Natural Science Foundation of China(Nos.22278257 and 21804084)the Key R&D Program of Shaanxi Province(No.2022GY-272)+2 种基金the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.22JY013)the Chinese Postdoctoral Science Foundation(No.2021M692000)Young Talent Support Program Project of Shaanxi University Science and Technology Association(No.20200424)for the funding the research.
文摘Currently,due to improvements in living standards,people are paying more attention to all-around disease prevention and health care.Self-powered implantable“tissue batteries”integrated with electrochemical materials are essential for disease prevention,diagnosis,treatment,postoperative therapy,and healthcare applications.We propose and define new concepts of“tissue batteries”-self-powered tissue batteries(SPTBs)-are flexible self-powered implantable systems or platforms based on electroactive biomaterials,acting at the interface of biological tissue.Based on the electrical phenomenon of living organisms in life activities,there has been an increased attention to SPTBs for tissue repair promotion.SPTBs take advantages of both the preeminent biocompatibility of biomaterials and the promotion of time-honored electrical stimulation therapy for tissue recovery,which are very promising for human illness treatment.However,studies on clinical applications of SPTBs are impeded by a lack of comprehensive cognitive assessment of SPTBs.Herein,SPTBs for life and health applications are comprehensively reviewed.First,electrochemical materials and their across-the-board applications for several types of SPTBs are introduced and compared with regard to disease prevention,diagnosis,precision therapy,and personalized health monitoring.Then,the potential mechanisms for SPTBs for tissue repair promotion are discussed.Finally,the prospective challenges are summarized and recommendations for future research are provided.This review elucidates on the significance and versatility of SPTBs for various medical applications.
基金the National Natural Science Foundation of China(2207081675)Science and Technology Project of Xianyang City(Grant 2018k02-28)+3 种基金Fellowship of China Postdoctoral Science Foundation(2021M692000)Key R&D Program of Shaanxi Province(2022GY-272)Young Talent Support Program Project of Shaanxi University Science and Technology Association(20200424)Department of education’s Production-Study-Research combined innovation Funding-“Blue fire plan(Huizhou)”of 2018(CXZJHZ201801).
文摘Nowadays, diverse leather usage conditions and increasing demands from consumers challenge the leather industry. Traditional leather manufacturing is facing long-term challenges, including low-value threshold, confined applica-tion fields, and environmental issues. Leather inherits all the biomimetic properties of natural skin such as flexibility, sanitation, cold resistance, biocompatibility, biodegradability, and other cross-domain functions, achieving unre-mitting attention in multi-functional bio-based materials. Series of researches have been devoted to creating and developing leather-based flexible multi-functional bio-materials, including antibacterial leather, conductive leather, flame-retardant leather, self-cleaning leather, aromatic leather, and electromagnetic shielding leather. In this review, we provide a comprehensive overview of the commonly used leather-based functional materials. Furthermore, the possible challenges for the development of functional leathers are proposed, and expected development directions of leather-based functional materials are discussed. This review may promote and inspire the emerging preparation and applications of leather for flexible functional bio-based materials.
基金National Key Research and Development Program of China(2017YFB0308500)National Natural Science Foundation of China(22078183).
文摘With the characteristics of controllable charge and environmental friendliness,amphoteric polymers can be used in post-tanning process to solve the problems that arise during leather making and are caused by the low absorption rate of single-charge chemicals,incompatibility with new tanning methods,and complex operation process.In this review,the structure,performance,and preparation of amphoteric polymers are reported.Then,the charge change of collagen during different tanning and pH treatments is introduced.Finally,the application and development of amphoteric polymers during the post-tanning process of leather making are discussed.This review has certain guiding significance to the preparation and application of amphoteric polymers for tanning system.
