The modal is a type of auxiliary verb that is used to indicate modality.There are thirteen modal auxiliaries including some past tense forms.In this paper,the modals and semi-modals will be studied through analyzing f...The modal is a type of auxiliary verb that is used to indicate modality.There are thirteen modal auxiliaries including some past tense forms.In this paper,the modals and semi-modals will be studied through analyzing fifteen sample sentences and referring some grammar books.At last,some suggestions for ESL or ESL teacher to teach modals will be provided.展开更多
In this research, the author considers the evidence provided by a corpus of Late Modem English grammars for our understanding of the development of the modals as politeness markers. It is possible to see how the modal...In this research, the author considers the evidence provided by a corpus of Late Modem English grammars for our understanding of the development of the modals as politeness markers. It is possible to see how the modals and their accompanied senses are explained in an official （and often either prescriptive or proscriptive） perspective. This is another aspect which cannot be ascertained from the usage based on corpora which seem to be popular as sources of evidence in historical pragmatics. In this sense, this research brings some novel perspective to this aspect of academic study. It is possible to notice that the significations involves concept or senses which extend across a semantic--pragmatic domain which includes politeness. We can see that certain softening senses are key elements to mark polite usage. The main data used come from the descriptions of the modal auxiliary verb in a corpus of grammar books from the period. Usage and manner books are also consulted as a secondary resource. The manner book in particular is quite helpful for our understanding of how linguistic politeness was regarded at the time. Such texts also help us to find a certain network of senses which are related to polite expressions.展开更多
With the development of global economy, more and more business negotiations are proceeding in which conflicts and disputes are inevitable. Business negotiations involve interpersonal relationships, which is usually ex...With the development of global economy, more and more business negotiations are proceeding in which conflicts and disputes are inevitable. Business negotiations involve interpersonal relationships, which is usually expressed by mood and modality. Modal verbs, as an essential approach for expressing politeness with rich meanings of modality, are widely employed in business negotiations.This paper focuses on analyzing the polite usages of modal verbs in business negotiations by Politeness Principle. Based on this theory, three interpersonal functions expressed by modal verbs are to be studied: Cost-and-Benefit, Humor and Choice.展开更多
An articulated vehicle is simplified as a multibody system. tires are simplified asparagraphic linear springs with damping, and the differential equations of system motion aregiven. Taking the ZL10 loader as an exampl...An articulated vehicle is simplified as a multibody system. tires are simplified asparagraphic linear springs with damping, and the differential equations of system motion aregiven. Taking the ZL10 loader as an example, and measuring three-dimensional dynamicstiffness and damping of the tires, seven orders of natural frequencies and related natural modesare obtained by modal analysis, and shown on the computer with three-dimensional moving pic-tures. The following conclusions are obtained: the first order frequency relates to the horizontalstability, the second order frequency relates to the vertical stability, and each order of frequencyrelates to the comfortability. All results of this work can be applied .to monitor stability and eval-uate comfortability.展开更多
Uncertain parameters are widespread in engineering systems.This study investigates the modal analysis of a fluid-conveying pipe subjected to elastic supports with unknown-but-bound parameters.The governing equation fo...Uncertain parameters are widespread in engineering systems.This study investigates the modal analysis of a fluid-conveying pipe subjected to elastic supports with unknown-but-bound parameters.The governing equation for the elastically supported fluid-conveying pipe is transformed into ordinary differential equations using the Galerkin truncation method.The Chebyshev interval approach,integrated with the assumed mode method is then used to investigate the effects of uncertainties of support stiffness,fluid speed,and pipe length on the natural frequencies and mode shapes of the pipe.Additionally,both symmetrical and asymmetrical support stiffnesses are discussed.The accuracy and effectiveness of the Chebyshev interval approach are verified through comparison with the Monte Carlo method.The results reveal that,for the same deviation coefficient,uncertainties in symmetrical support stiffness have a greater impact on the first four natural frequencies than those of the asymmetrical one.There may be significant differences in the sensitivity of natural frequencies and mode shapes of the same order to uncertain parameters.Notably,mode shapes susceptible to uncertain parameters exhibit wider fluctuation intervals near the elastic supports,requiring more attention.展开更多
Microrobotic systems are emerging as transformative technology for minimally invasive medicine,driven by innovations in actuation mechanisms,advanced fabrication paradigms,and multifunctional system integration.This c...Microrobotic systems are emerging as transformative technology for minimally invasive medicine,driven by innovations in actuation mechanisms,advanced fabrication paradigms,and multifunctional system integration.This comprehensive review analyzes the evolution of microrobotic technologies through three critical dimensions:(1)actuation modalities,including magnetic,optical,acoustic,chemical,and biological actuation,with a focus on the synergistic advantages of hybrid actuation strategies in complex internal physiological environments;(2)Fabrication methods cover technolo-gies such as photolithography,microinjection molding,self-assembly,and 3D printing,emphasizing innovative strategies involving multi-technology integration and collaborative manufacturing of bio/non-bio hybrid materials;(3)Internal phys-iological applications involve disease diagnosis,targeted drug delivery,minimally invasive surgery,tissue engineering,and cell manipulation,highlighting the broad prospects of microrobots in precision medicine.Despite remarkable progress,critical challenges remain,including low actuation efficiency,as seen in acoustic systems,limited biocompatibility,exem-plified by the toxicity of hydrogen peroxide in chemical actuation,delayed clinical translation,and other related challenges that must be addressed to advance the field.展开更多
As a multidisciplinary phenomenon,panel aeroelasticity in shock-dominated flow is featured by two primary interactions:Fluid-Structure Interactions(FSIs)and Shock-Boundary Layer Interactions(SBLIs).The former raises s...As a multidisciplinary phenomenon,panel aeroelasticity in shock-dominated flow is featured by two primary interactions:Fluid-Structure Interactions(FSIs)and Shock-Boundary Layer Interactions(SBLIs).The former raises structural concerns,and the latter is of aerodynamic interest.Thus,panel aeroelasticity in shock-dominated flow represents a vital topic for the development and optimization of supersonic vehicles and propulsion systems.This review systematically summarizes recent advances in the methodologies applied to capture structural and fluid dynamics,including theoretical models,numerical simulations,and wind tunnel experiments.The application of data-driven modal decomposition,an advanced technique to extract physically crucial features,on the topic is introduced.From the perspective of FSIs,the distinctive aeroelastic behaviors in shock-dominated flow,including hysteresis phenomena and nonlinear responses,are highlighted.From the perspective of SBLIs,the modifications in their spatial and temporal characteristics imposed by the aeroelastic responses are emphasized.Motivated by the interaction between the shock waves and structural response,different strategies have been proposed to implement aeroelastic suppression and shock control,which have the potential to enhance structural safety and aerodynamic performance in the next generation of high-speed flight vehicles.展开更多
In the version of the article originally published in the volume 68,issue 12,2025 of Sci China Mater(pages 4413-4422,https://doi.org/10.1007/s40843-025-3667-7),the Chinese name of the co-first author(肖天孝)was incorr...In the version of the article originally published in the volume 68,issue 12,2025 of Sci China Mater(pages 4413-4422,https://doi.org/10.1007/s40843-025-3667-7),the Chinese name of the co-first author(肖天孝)was incorrect.The corrected Chinese name is:肖天笑.展开更多
Traditional dynamic analysis of mechanical structures,often limited to individual beams or plates,fails to fully capture their dynamic behaviors.In systems where space and mass are constrained,such as the battery supp...Traditional dynamic analysis of mechanical structures,often limited to individual beams or plates,fails to fully capture their dynamic behaviors.In systems where space and mass are constrained,such as the battery support structures in electric aircraft,conventional absorbers and isolators are insufficient for effective vibration control.This study simplifies the battery support structure of electric aircraft as an integrated composite beam consisting of three interconnected beams,and investigated its structural dynamics properties and nonlinear vibration control under thermal conditions caused by battery heat.The nonlinear vibration control is performed using the Nitinol steel wire ropes(Ni Ti-ST),with nonlinear damping properties.The natural frequencies of system are determined using the Rayleigh-Ritz technique.Theoretical results are validated through both Finite Element Method(FEM)and hammer tests.Moreover,the dynamic equations are derived using the Lagrange method and discretized via the Galerkin Truncation Method(GTM).The Harmonic Balance Method(HBM)is used to evaluate the vibration responses of the integrated model,with further verification through the Runge-Kutta Method(RKM).The experiments are conducted to corroborate the theoretical analysis.The results show that the system frequency changes in stages with the increase of the stiffness of the integrated composite beam connection.Especially in the case of varying environments,as the temperature increases,the frequency of system will first increase to a certain maximum value and then gradually decrease.Furthermore,the NiTi-ST effectively reduces vibration in the integrated composite beam,particularly under varying temperatures and external excitations.展开更多
Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the structure.Therefore,it is particularly significant to identify the structural modal parameters accordi...Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the structure.Therefore,it is particularly significant to identify the structural modal parameters according to the monitoring data information in the structural health monitoring(SHM)system,so as to provide a scientific basis for structural damage identification and dynamic model modification.In view of this,this paper reviews methods for identifying structural modal parameters under environmental excitation and briefly describes how to identify structural damages based on the derived modal parameters.The paper primarily introduces data-driven modal parameter recognition methods(e.g.,time-domain,frequency-domain,and time-frequency-domain methods,etc.),briefly describes damage identification methods based on the variations of modal parameters(e.g.,natural frequency,modal shapes,and curvature modal shapes,etc.)and modal validation methods(e.g.,Stability Diagram and Modal Assurance Criterion,etc.).The current status of the application of artificial intelligence(AI)methods in the direction of modal parameter recognition and damage identification is further discussed.Based on the pre-vious analysis,the main development trends of structural modal parameter recognition and damage identification methods are given to provide scientific references for the optimized design and functional upgrading of SHM systems.展开更多
Present of wind power is sporadically and cannot be utilized as the only fundamental load of energy sources.This paper proposes a wind-solar hybrid energy storage system(HESS)to ensure a stable supply grid for a longe...Present of wind power is sporadically and cannot be utilized as the only fundamental load of energy sources.This paper proposes a wind-solar hybrid energy storage system(HESS)to ensure a stable supply grid for a longer period.A multi-objective genetic algorithm(MOGA)and state of charge(SOC)region division for the batteries are introduced to solve the objective function and configuration of the system capacity,respectively.MATLAB/Simulink was used for simulation test.The optimization results show that for a 0.5 MW wind power and 0.5 MW photovoltaic system,with a combination of a 300 Ah lithium battery,a 200 Ah lead-acid battery,and a water storage tank,the proposed strategy reduces the system construction cost by approximately 18,000 yuan.Additionally,the cycle count of the electrochemical energy storage systemincreases from4515 to 4660,while the depth of discharge decreases from 55.37%to 53.65%,achieving shallow charging and discharging,thereby extending battery life and reducing grid voltage fluctuations significantly.The proposed strategy is a guide for stabilizing the grid connection of wind and solar power generation,capability allocation,and energy management of energy conservation systems.展开更多
Accurately estimating the State of Health(SOH)and Remaining Useful Life(RUL)of lithium-ion batteries(LIBs)is crucial for the continuous and stable operation of battery management systems.However,due to the complex int...Accurately estimating the State of Health(SOH)and Remaining Useful Life(RUL)of lithium-ion batteries(LIBs)is crucial for the continuous and stable operation of battery management systems.However,due to the complex internal chemical systems of LIBs and the nonlinear degradation of their performance,direct measurement of SOH and RUL is challenging.To address these issues,the Twin Support Vector Machine(TWSVM)method is proposed to predict SOH and RUL.Initially,the constant current charging time of the lithium battery is extracted as a health indicator(HI),decomposed using Variational Modal Decomposition(VMD),and feature correlations are computed using Importance of Random Forest Features(RF)to maximize the extraction of critical factors influencing battery performance degradation.Furthermore,to enhance the global search capability of the Convolution Optimization Algorithm(COA),improvements are made using Good Point Set theory and the Differential Evolution method.The Improved Convolution Optimization Algorithm(ICOA)is employed to optimize TWSVM parameters for constructing SOH and RUL prediction models.Finally,the proposed models are validated using NASA and CALCE lithium-ion battery datasets.Experimental results demonstrate that the proposed models achieve an RMSE not exceeding 0.007 and an MAPE not exceeding 0.0082 for SOH and RUL prediction,with a relative error in RUL prediction within the range of[-1.8%,2%].Compared to other models,the proposed model not only exhibits superior fitting capability but also demonstrates robust performance.展开更多
Infectious bone defects represent a substantial challenge in clinical practice,necessitating the deployment of advanced therapeutic strategies.This study presents a treatment modality that merges a mild photothermal t...Infectious bone defects represent a substantial challenge in clinical practice,necessitating the deployment of advanced therapeutic strategies.This study presents a treatment modality that merges a mild photothermal therapy hydrogel with a pulsed drug delivery mechanism.The system is predicated on a hydrogel matrix that is thermally responsive,characteristic of bone defect sites,facilitating controlled and site-specific drug release.The cornerstone of this system is the incorporation of mild photothermal nanoparticles,which are activated within the temperature range of 40–43°C,thereby enhancing the precision and efficacy of drug delivery.Our findings demonstrate that the photothermal response significantly augments the localized delivery of therapeutic agents,mitigating systemic side effects and bolstering efficacy at the defect site.The synchronized pulsed release,cooperated with mild photothermal therapy,effectively addresses infection control,and promotes bone regeneration.This approach signifies a considerable advancement in the management of infectious bone defects,offering an effective and patient-centric alternative to traditional methods.Our research endeavors to extend its applicability to a wider spectrum of tissue regeneration scenarios,underscoring its transformative potential in the realm of regenerative medicine.展开更多
Objective Traditional Chinese medicine(TCM)incorporates traditional diagnostic methods and several major treatment modalities including Chinese herbal medicine,Chinese patent medicine,and non-pharmacological methods s...Objective Traditional Chinese medicine(TCM)incorporates traditional diagnostic methods and several major treatment modalities including Chinese herbal medicine,Chinese patent medicine,and non-pharmacological methods such as acupuncture and tuina.Even though TCM is used daily by more than 70,000 healthcare facilities and over 700,000 clinical practitioners in China,there is a poor understanding of the extent to which TCM diagnostic methods are used,how different treatment modalities are deployed in general,and what major factors may affect the integration of TCM and Western medicine.This study aimed to fill this void in the literature.Methods In the 2021 National Healthcare Improvement Evaluation Survey,we included three questions gauging the perception and practices of TCM amongst physicians working in TCM-related facilities,investigating the frequency of their deployment of TCM diagnostic methods,and predominant TCM treatment methods.Our empirical analysis included descriptive statistics,intergroup chi-square analysis,and binary logistic regression to examine the association between different types of facilities and individual characteristics and TCM utilization patterns.Results A total of 7618 clinical physicians comprised our study sample.Among them,84.27%have integrated TCM and Western medicine in their clinical practice,and 80.77%of TCM practitioners used the 4 diagnostic methods as a tool in their clinical practice.Chinese herbal medicine was the most widely utilized modality by Chinese TCM physicians(used by 88.49%of respondents),compared with the Chinese patent medicine and non-pharmacological TCM methods,which were used by 73.14%,and 69.39%,respectively.Herbal tea as an out-of-pocket health-maintenance intervention is also a notable practice,recommended by 29.43%of physicians.Significant variations exist across certain institutions,departments,and individual practitioners.Conclusion Given that most of the surveyed physicians integrated TCM with Western medicine in their clinical practices,the practice of“pure TCM”appears to be obsolete in China’s tertiary healthcare institutions.Notably,remarkable variation exists in the use of different TCM modalities across institutions and among individuals,which might be related to and thus limited by the practitioners’experience.Future research focusing on the efficacy and safety of TCM interventions for specific diseases,the development of standardized clinical guidelines,and the enhancement of TCM education and training are called for to optimize TCM-Western medicine integration.展开更多
This article extends the foundational work of Wang and Wang on modal logic over lattices.Building upon their framework using polyadic modal logic with binary modalities<sup>and<inf>under standard Kripke se...This article extends the foundational work of Wang and Wang on modal logic over lattices.Building upon their framework using polyadic modal logic with binary modalities<sup>and<inf>under standard Kripke semantics to axiomatize lattice structures,we focus on the modal characterization of bounded lattices and their extensions relevant to logical systems.By introducing nullary modalities 1(maximum element)and 0(minimum element),we first establish a modal axiomatic system for bounded lattices.Subsequently,we provide pure formula characterizations of complementation and orthocomplementation relations in lattices,along with corresponding completeness results.As key applications,we present modal characterizations of fundamental logical algebraic structures:Boolean algebras,orthomodular lattices,and Heyting algebras.The last section develops novel axiomatization results for atomic lattices and atomless lattices.Throughout this work,all axiomatic systems are shown to be strongly complete via pureformula extensions,demonstrating how hybrid modal languages with nullary operators can uniformly capture boundary elements,complementation properties,and latticetheoretic operations central to both classical and nonclassical logics.展开更多
In modal logic,topological semantics is an intuitive and natural special case of neighbourhood semantics.This paper stems from the observation that the satisfaction relation of topological semantics applies to subset ...In modal logic,topological semantics is an intuitive and natural special case of neighbourhood semantics.This paper stems from the observation that the satisfaction relation of topological semantics applies to subset spaces which are more general than topological spaces.The minimal modal logic which is strongly sound and complete with respect to the class of subset spaces is found.Soundness and completeness results of some famous modal logics(e.g.S4,S5 and Tr)with respect to various important classes of subset spaces(eg intersection structures and complete fields of sets)are also proved.In the meantime,some known results,e.g.the soundness and completeness of Tr with respect to the class of discrete topological spaces,are proved directly using some modifications of the method of canonical mode1,without a detour via neighbourhood semantics or relational semantics.展开更多
In the present paper,we give a systematic study of the discrete correspondence the-ory and topological correspondence theory of modal meet-implication logic and moda1 meet-semilattice logic,in the semantics provided i...In the present paper,we give a systematic study of the discrete correspondence the-ory and topological correspondence theory of modal meet-implication logic and moda1 meet-semilattice logic,in the semantics provided in[21].The special features of the present paper include the following three points:the first one is that the semantic structure used is based on a semilattice rather than an ordinary partial order,the second one is that the propositional vari-ables are interpreted as filters rather than upsets,and the nominals,which are the“first-order counterparts of propositional variables,are interpreted as principal filters rather than principal upsets;the third one is that in topological correspondence theory,the collection of admissi-ble valuations is not closed under taking disjunction,which makes the proof of the topological Ackermann 1emma different from existing settings.展开更多
Normal mode extraction has attracted extensive attention over the past few decades due to its practical value in enhancing the performance of underwater acoustic signal processing.Singular value decomposition(SVD)is a...Normal mode extraction has attracted extensive attention over the past few decades due to its practical value in enhancing the performance of underwater acoustic signal processing.Singular value decomposition(SVD)is an effective method to extract modal depth functions using vertical line arrays(VLA),particularly in scenarios when no prior environment information is available.However,the SVD method requires rigorous orthogonality conditions,and its performance severely degenerates in the presence of mode degeneracy.Consequently,the SVD approach is often not feasible in practical scenarios.This paper proposes a full rank decomposition(FRD)method to address these issues.Compared to the SVD method,the FRD method has three distinct advantages:1)the conditions that the FRD method requires are much easier to be fulfilled in practical scenarios;2)both modal depth functions and wavenumbers can be simultaneously extracted via the FRD method;3)the FRD method is not affected by the phenomenon of mode degeneracy.Numerical simulations are conducted in two types of waveguides to verify the FRD method.The impacts of environment configurations and noise levels on the precision of the extracted modal depth functions and wavenumbers are also investigated through simulation.展开更多
In view of the demand for intelligent upgrading of quartz crucible manufacturing equipment,this study proposes a design scheme of large-scale quartz crucible feeding frame system with innovative structure,and analyzes...In view of the demand for intelligent upgrading of quartz crucible manufacturing equipment,this study proposes a design scheme of large-scale quartz crucible feeding frame system with innovative structure,and analyzes the vibration characteristics of this structure in view of the large vibration and instability during operation.In order to study the relationship between the operating vibration and the natural frequency and avoid resonance,the calculated mode was analyzed via ANSYS Workbench,and the experimental mode results were obtained by using percussion test and compared with the calculated mode.It is concluded that the natural frequencies of the first six orders of the large quartz crucible feeding frame are between 5.13 and 23.29,and the main deformation is distributed at the end of the turning mechanism.The analysis results show that the first-order natural frequency of the system has a safety margin of 1.55 times comparing with the working frequency of the drive motor(12 Hz),which effectively avoids the risk of resonance.The feeding frame adopts a double-column truss composite structure,and the layout of the specially designed stiffener network and high-precision guide rails ensures the lightweight structure and significantly improves the dynamic stability of the system.The practical effect of the large-scale quartz crucible feeding frame shows that the structural design is successful,and has reference significance for the structural design of the same type of automatic manufacturing equipment.展开更多
BACKGROUND Glaucoma is the leading cause of irreversible blindness worldwide,with 60.5 million affected individuals,of whom 11 million are from India.Due to its asymptomatic nature,the disease largely remains underdia...BACKGROUND Glaucoma is the leading cause of irreversible blindness worldwide,with 60.5 million affected individuals,of whom 11 million are from India.Due to its asymptomatic nature,the disease largely remains underdiagnosed or diagnosed in advanced stages,where little can be done to salvage functional vision.The literature suggests that a lack of knowledge is one of the reasons for its grave consequences.Assessment of awareness is the first step in planning management.Several studies have been conducted in the Indian community,but data from healthcare providers,who play a significant role in educating the masses directly or indirectly,are limited.AIM To identify awareness,knowledge,and attitudes about glaucoma among healthcare workers in a tertiary center in India.METHODS This cross-sectional study was conducted at a tertiary care institute in Eastern India.Data were collected from 423 participants by systematic stratified sampling after Institutional Ethics Committee approval via a pretested,self-designed,semistructured,validated questionnaire.Statistical analyses were performed using the Statistical Package for Social Sciences Software v22.0.Continuous variables are expressed as the means±SD for parametric values and medians with interquartile ranges for nonparametric values.The associations between the variables were studied via multivariate linear and logistic regression.P<0.05 was considered statistically significant.RESULTS Most respondents were 20–30 years old(n=345,81.6%).The knowledge regarding glaucoma was good,and almost 56.3%of the participants gained knowledge from their medical training.The majority were aware that it has a familial predisposition and is secondary to high intraocular pressure,leading to irreversible peripheral vision loss.Only 42%knew about the life-long requirements of treatment.The resident group scored highest on knowledgeand attitude-based questions,whereas the faculty group scored highest on practice-based questions.Although 62%of the nursing staff had good attitude scores,their knowledge and practice scores were lower.The occupation group response difference was statistically significant(P<0.05)for all the knowledge-based questions.CONCLUSION Although the majority of healthcare providers are aware of glaucoma,there is a dearth of knowledge about treatment modalities.Education via seminars and media can improve their knowledge,attitudes,and practices.展开更多
文摘The modal is a type of auxiliary verb that is used to indicate modality.There are thirteen modal auxiliaries including some past tense forms.In this paper,the modals and semi-modals will be studied through analyzing fifteen sample sentences and referring some grammar books.At last,some suggestions for ESL or ESL teacher to teach modals will be provided.
文摘In this research, the author considers the evidence provided by a corpus of Late Modem English grammars for our understanding of the development of the modals as politeness markers. It is possible to see how the modals and their accompanied senses are explained in an official （and often either prescriptive or proscriptive） perspective. This is another aspect which cannot be ascertained from the usage based on corpora which seem to be popular as sources of evidence in historical pragmatics. In this sense, this research brings some novel perspective to this aspect of academic study. It is possible to notice that the significations involves concept or senses which extend across a semantic--pragmatic domain which includes politeness. We can see that certain softening senses are key elements to mark polite usage. The main data used come from the descriptions of the modal auxiliary verb in a corpus of grammar books from the period. Usage and manner books are also consulted as a secondary resource. The manner book in particular is quite helpful for our understanding of how linguistic politeness was regarded at the time. Such texts also help us to find a certain network of senses which are related to polite expressions.
文摘With the development of global economy, more and more business negotiations are proceeding in which conflicts and disputes are inevitable. Business negotiations involve interpersonal relationships, which is usually expressed by mood and modality. Modal verbs, as an essential approach for expressing politeness with rich meanings of modality, are widely employed in business negotiations.This paper focuses on analyzing the polite usages of modal verbs in business negotiations by Politeness Principle. Based on this theory, three interpersonal functions expressed by modal verbs are to be studied: Cost-and-Benefit, Humor and Choice.
文摘An articulated vehicle is simplified as a multibody system. tires are simplified asparagraphic linear springs with damping, and the differential equations of system motion aregiven. Taking the ZL10 loader as an example, and measuring three-dimensional dynamicstiffness and damping of the tires, seven orders of natural frequencies and related natural modesare obtained by modal analysis, and shown on the computer with three-dimensional moving pic-tures. The following conclusions are obtained: the first order frequency relates to the horizontalstability, the second order frequency relates to the vertical stability, and each order of frequencyrelates to the comfortability. All results of this work can be applied .to monitor stability and eval-uate comfortability.
基金supported by the National Natural Science Foundation of China(Grant Nos.12272211,12072181,and 12121002).
文摘Uncertain parameters are widespread in engineering systems.This study investigates the modal analysis of a fluid-conveying pipe subjected to elastic supports with unknown-but-bound parameters.The governing equation for the elastically supported fluid-conveying pipe is transformed into ordinary differential equations using the Galerkin truncation method.The Chebyshev interval approach,integrated with the assumed mode method is then used to investigate the effects of uncertainties of support stiffness,fluid speed,and pipe length on the natural frequencies and mode shapes of the pipe.Additionally,both symmetrical and asymmetrical support stiffnesses are discussed.The accuracy and effectiveness of the Chebyshev interval approach are verified through comparison with the Monte Carlo method.The results reveal that,for the same deviation coefficient,uncertainties in symmetrical support stiffness have a greater impact on the first four natural frequencies than those of the asymmetrical one.There may be significant differences in the sensitivity of natural frequencies and mode shapes of the same order to uncertain parameters.Notably,mode shapes susceptible to uncertain parameters exhibit wider fluctuation intervals near the elastic supports,requiring more attention.
基金National Natural Science Foundation of China(Grant No.61903157)the Foundation of State Key Laboratory of Robotics(Grand No.2024-O08).
文摘Microrobotic systems are emerging as transformative technology for minimally invasive medicine,driven by innovations in actuation mechanisms,advanced fabrication paradigms,and multifunctional system integration.This comprehensive review analyzes the evolution of microrobotic technologies through three critical dimensions:(1)actuation modalities,including magnetic,optical,acoustic,chemical,and biological actuation,with a focus on the synergistic advantages of hybrid actuation strategies in complex internal physiological environments;(2)Fabrication methods cover technolo-gies such as photolithography,microinjection molding,self-assembly,and 3D printing,emphasizing innovative strategies involving multi-technology integration and collaborative manufacturing of bio/non-bio hybrid materials;(3)Internal phys-iological applications involve disease diagnosis,targeted drug delivery,minimally invasive surgery,tissue engineering,and cell manipulation,highlighting the broad prospects of microrobots in precision medicine.Despite remarkable progress,critical challenges remain,including low actuation efficiency,as seen in acoustic systems,limited biocompatibility,exem-plified by the toxicity of hydrogen peroxide in chemical actuation,delayed clinical translation,and other related challenges that must be addressed to advance the field.
基金supported by the National Natural Science Foundation of China(No.12372233)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(No.25GH01020005)the“111 Project”of China(No.B17037)。
文摘As a multidisciplinary phenomenon,panel aeroelasticity in shock-dominated flow is featured by two primary interactions:Fluid-Structure Interactions(FSIs)and Shock-Boundary Layer Interactions(SBLIs).The former raises structural concerns,and the latter is of aerodynamic interest.Thus,panel aeroelasticity in shock-dominated flow represents a vital topic for the development and optimization of supersonic vehicles and propulsion systems.This review systematically summarizes recent advances in the methodologies applied to capture structural and fluid dynamics,including theoretical models,numerical simulations,and wind tunnel experiments.The application of data-driven modal decomposition,an advanced technique to extract physically crucial features,on the topic is introduced.From the perspective of FSIs,the distinctive aeroelastic behaviors in shock-dominated flow,including hysteresis phenomena and nonlinear responses,are highlighted.From the perspective of SBLIs,the modifications in their spatial and temporal characteristics imposed by the aeroelastic responses are emphasized.Motivated by the interaction between the shock waves and structural response,different strategies have been proposed to implement aeroelastic suppression and shock control,which have the potential to enhance structural safety and aerodynamic performance in the next generation of high-speed flight vehicles.
文摘In the version of the article originally published in the volume 68,issue 12,2025 of Sci China Mater(pages 4413-4422,https://doi.org/10.1007/s40843-025-3667-7),the Chinese name of the co-first author(肖天孝)was incorrect.The corrected Chinese name is:肖天笑.
基金supported by the National Natural Science Foundation of China(No.12272240)the Liaoning Revitalization Talents Program,China(No.XLYC2203197)。
文摘Traditional dynamic analysis of mechanical structures,often limited to individual beams or plates,fails to fully capture their dynamic behaviors.In systems where space and mass are constrained,such as the battery support structures in electric aircraft,conventional absorbers and isolators are insufficient for effective vibration control.This study simplifies the battery support structure of electric aircraft as an integrated composite beam consisting of three interconnected beams,and investigated its structural dynamics properties and nonlinear vibration control under thermal conditions caused by battery heat.The nonlinear vibration control is performed using the Nitinol steel wire ropes(Ni Ti-ST),with nonlinear damping properties.The natural frequencies of system are determined using the Rayleigh-Ritz technique.Theoretical results are validated through both Finite Element Method(FEM)and hammer tests.Moreover,the dynamic equations are derived using the Lagrange method and discretized via the Galerkin Truncation Method(GTM).The Harmonic Balance Method(HBM)is used to evaluate the vibration responses of the integrated model,with further verification through the Runge-Kutta Method(RKM).The experiments are conducted to corroborate the theoretical analysis.The results show that the system frequency changes in stages with the increase of the stiffness of the integrated composite beam connection.Especially in the case of varying environments,as the temperature increases,the frequency of system will first increase to a certain maximum value and then gradually decrease.Furthermore,the NiTi-ST effectively reduces vibration in the integrated composite beam,particularly under varying temperatures and external excitations.
基金supported by the Innovation Foundation of Provincial Education Department of Gansu(2024B-005)the Gansu Province National Science Foundation(22YF7GA182)the Fundamental Research Funds for the Central Universities(No.lzujbky2022-kb01)。
文摘Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the structure.Therefore,it is particularly significant to identify the structural modal parameters according to the monitoring data information in the structural health monitoring(SHM)system,so as to provide a scientific basis for structural damage identification and dynamic model modification.In view of this,this paper reviews methods for identifying structural modal parameters under environmental excitation and briefly describes how to identify structural damages based on the derived modal parameters.The paper primarily introduces data-driven modal parameter recognition methods(e.g.,time-domain,frequency-domain,and time-frequency-domain methods,etc.),briefly describes damage identification methods based on the variations of modal parameters(e.g.,natural frequency,modal shapes,and curvature modal shapes,etc.)and modal validation methods(e.g.,Stability Diagram and Modal Assurance Criterion,etc.).The current status of the application of artificial intelligence(AI)methods in the direction of modal parameter recognition and damage identification is further discussed.Based on the pre-vious analysis,the main development trends of structural modal parameter recognition and damage identification methods are given to provide scientific references for the optimized design and functional upgrading of SHM systems.
基金supported by a Horizontal Project on the Development of a Hybrid Energy Storage Simulation Model for Wind Power Based on an RT-LAB Simulation System(PH2023000190)the Inner Mongolia Natural Science Foundation Project and the Optimization of Exergy Efficiency of a Hybrid Energy Storage System with Crossover Control for Wind Power(2023JQ04).
文摘Present of wind power is sporadically and cannot be utilized as the only fundamental load of energy sources.This paper proposes a wind-solar hybrid energy storage system(HESS)to ensure a stable supply grid for a longer period.A multi-objective genetic algorithm(MOGA)and state of charge(SOC)region division for the batteries are introduced to solve the objective function and configuration of the system capacity,respectively.MATLAB/Simulink was used for simulation test.The optimization results show that for a 0.5 MW wind power and 0.5 MW photovoltaic system,with a combination of a 300 Ah lithium battery,a 200 Ah lead-acid battery,and a water storage tank,the proposed strategy reduces the system construction cost by approximately 18,000 yuan.Additionally,the cycle count of the electrochemical energy storage systemincreases from4515 to 4660,while the depth of discharge decreases from 55.37%to 53.65%,achieving shallow charging and discharging,thereby extending battery life and reducing grid voltage fluctuations significantly.The proposed strategy is a guide for stabilizing the grid connection of wind and solar power generation,capability allocation,and energy management of energy conservation systems.
基金funded by the Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture under Grant GJZJ20220802。
文摘Accurately estimating the State of Health(SOH)and Remaining Useful Life(RUL)of lithium-ion batteries(LIBs)is crucial for the continuous and stable operation of battery management systems.However,due to the complex internal chemical systems of LIBs and the nonlinear degradation of their performance,direct measurement of SOH and RUL is challenging.To address these issues,the Twin Support Vector Machine(TWSVM)method is proposed to predict SOH and RUL.Initially,the constant current charging time of the lithium battery is extracted as a health indicator(HI),decomposed using Variational Modal Decomposition(VMD),and feature correlations are computed using Importance of Random Forest Features(RF)to maximize the extraction of critical factors influencing battery performance degradation.Furthermore,to enhance the global search capability of the Convolution Optimization Algorithm(COA),improvements are made using Good Point Set theory and the Differential Evolution method.The Improved Convolution Optimization Algorithm(ICOA)is employed to optimize TWSVM parameters for constructing SOH and RUL prediction models.Finally,the proposed models are validated using NASA and CALCE lithium-ion battery datasets.Experimental results demonstrate that the proposed models achieve an RMSE not exceeding 0.007 and an MAPE not exceeding 0.0082 for SOH and RUL prediction,with a relative error in RUL prediction within the range of[-1.8%,2%].Compared to other models,the proposed model not only exhibits superior fitting capability but also demonstrates robust performance.
基金supported by the National Natural Science Foundation of China(32171354,82222015,82171001)The National Key Research and Development Program of China2023YFC2413600Research Funding from West China School/Hospital of Stomatology,Sichuan University(No.RCDWIS2023-1).
文摘Infectious bone defects represent a substantial challenge in clinical practice,necessitating the deployment of advanced therapeutic strategies.This study presents a treatment modality that merges a mild photothermal therapy hydrogel with a pulsed drug delivery mechanism.The system is predicated on a hydrogel matrix that is thermally responsive,characteristic of bone defect sites,facilitating controlled and site-specific drug release.The cornerstone of this system is the incorporation of mild photothermal nanoparticles,which are activated within the temperature range of 40–43°C,thereby enhancing the precision and efficacy of drug delivery.Our findings demonstrate that the photothermal response significantly augments the localized delivery of therapeutic agents,mitigating systemic side effects and bolstering efficacy at the defect site.The synchronized pulsed release,cooperated with mild photothermal therapy,effectively addresses infection control,and promotes bone regeneration.This approach signifies a considerable advancement in the management of infectious bone defects,offering an effective and patient-centric alternative to traditional methods.Our research endeavors to extend its applicability to a wider spectrum of tissue regeneration scenarios,underscoring its transformative potential in the realm of regenerative medicine.
基金The Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences——A Strategic Study on Healthy China Development and Health System Reform(2021-I2M-1-046).
文摘Objective Traditional Chinese medicine(TCM)incorporates traditional diagnostic methods and several major treatment modalities including Chinese herbal medicine,Chinese patent medicine,and non-pharmacological methods such as acupuncture and tuina.Even though TCM is used daily by more than 70,000 healthcare facilities and over 700,000 clinical practitioners in China,there is a poor understanding of the extent to which TCM diagnostic methods are used,how different treatment modalities are deployed in general,and what major factors may affect the integration of TCM and Western medicine.This study aimed to fill this void in the literature.Methods In the 2021 National Healthcare Improvement Evaluation Survey,we included three questions gauging the perception and practices of TCM amongst physicians working in TCM-related facilities,investigating the frequency of their deployment of TCM diagnostic methods,and predominant TCM treatment methods.Our empirical analysis included descriptive statistics,intergroup chi-square analysis,and binary logistic regression to examine the association between different types of facilities and individual characteristics and TCM utilization patterns.Results A total of 7618 clinical physicians comprised our study sample.Among them,84.27%have integrated TCM and Western medicine in their clinical practice,and 80.77%of TCM practitioners used the 4 diagnostic methods as a tool in their clinical practice.Chinese herbal medicine was the most widely utilized modality by Chinese TCM physicians(used by 88.49%of respondents),compared with the Chinese patent medicine and non-pharmacological TCM methods,which were used by 73.14%,and 69.39%,respectively.Herbal tea as an out-of-pocket health-maintenance intervention is also a notable practice,recommended by 29.43%of physicians.Significant variations exist across certain institutions,departments,and individual practitioners.Conclusion Given that most of the surveyed physicians integrated TCM with Western medicine in their clinical practices,the practice of“pure TCM”appears to be obsolete in China’s tertiary healthcare institutions.Notably,remarkable variation exists in the use of different TCM modalities across institutions and among individuals,which might be related to and thus limited by the practitioners’experience.Future research focusing on the efficacy and safety of TCM interventions for specific diseases,the development of standardized clinical guidelines,and the enhancement of TCM education and training are called for to optimize TCM-Western medicine integration.
基金supported by China Postdoctoral Science Foundation(2024M750225).
文摘This article extends the foundational work of Wang and Wang on modal logic over lattices.Building upon their framework using polyadic modal logic with binary modalities<sup>and<inf>under standard Kripke semantics to axiomatize lattice structures,we focus on the modal characterization of bounded lattices and their extensions relevant to logical systems.By introducing nullary modalities 1(maximum element)and 0(minimum element),we first establish a modal axiomatic system for bounded lattices.Subsequently,we provide pure formula characterizations of complementation and orthocomplementation relations in lattices,along with corresponding completeness results.As key applications,we present modal characterizations of fundamental logical algebraic structures:Boolean algebras,orthomodular lattices,and Heyting algebras.The last section develops novel axiomatization results for atomic lattices and atomless lattices.Throughout this work,all axiomatic systems are shown to be strongly complete via pureformula extensions,demonstrating how hybrid modal languages with nullary operators can uniformly capture boundary elements,complementation properties,and latticetheoretic operations central to both classical and nonclassical logics.
基金supported by the National Social Science Fund of China(No.20CZX048)。
文摘In modal logic,topological semantics is an intuitive and natural special case of neighbourhood semantics.This paper stems from the observation that the satisfaction relation of topological semantics applies to subset spaces which are more general than topological spaces.The minimal modal logic which is strongly sound and complete with respect to the class of subset spaces is found.Soundness and completeness results of some famous modal logics(e.g.S4,S5 and Tr)with respect to various important classes of subset spaces(eg intersection structures and complete fields of sets)are also proved.In the meantime,some known results,e.g.the soundness and completeness of Tr with respect to the class of discrete topological spaces,are proved directly using some modifications of the method of canonical mode1,without a detour via neighbourhood semantics or relational semantics.
基金supported by the Chinese Ministry of Education of Humanities and Social Science Project(23YJC72040003)the Key Project of Chinese Ministry of Education(22JJD720021)supported by the Natural Science Foundation of Shandong Province,China(project number:ZR2023QF021)。
文摘In the present paper,we give a systematic study of the discrete correspondence the-ory and topological correspondence theory of modal meet-implication logic and moda1 meet-semilattice logic,in the semantics provided in[21].The special features of the present paper include the following three points:the first one is that the semantic structure used is based on a semilattice rather than an ordinary partial order,the second one is that the propositional vari-ables are interpreted as filters rather than upsets,and the nominals,which are the“first-order counterparts of propositional variables,are interpreted as principal filters rather than principal upsets;the third one is that in topological correspondence theory,the collection of admissi-ble valuations is not closed under taking disjunction,which makes the proof of the topological Ackermann 1emma different from existing settings.
基金supported by the National Natural Science Foundation of China(Nos.12304504,12304506 and U22 A2012)the Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2021023)+1 种基金the Strategy Priority Research Program(Category B)of Chinese Academy of Sciences(Nos.XDB0700100 and XDB0700000)the Natural Science Foundation of Tianjin(No.22JCYBJC00070).
文摘Normal mode extraction has attracted extensive attention over the past few decades due to its practical value in enhancing the performance of underwater acoustic signal processing.Singular value decomposition(SVD)is an effective method to extract modal depth functions using vertical line arrays(VLA),particularly in scenarios when no prior environment information is available.However,the SVD method requires rigorous orthogonality conditions,and its performance severely degenerates in the presence of mode degeneracy.Consequently,the SVD approach is often not feasible in practical scenarios.This paper proposes a full rank decomposition(FRD)method to address these issues.Compared to the SVD method,the FRD method has three distinct advantages:1)the conditions that the FRD method requires are much easier to be fulfilled in practical scenarios;2)both modal depth functions and wavenumbers can be simultaneously extracted via the FRD method;3)the FRD method is not affected by the phenomenon of mode degeneracy.Numerical simulations are conducted in two types of waveguides to verify the FRD method.The impacts of environment configurations and noise levels on the precision of the extracted modal depth functions and wavenumbers are also investigated through simulation.
文摘In view of the demand for intelligent upgrading of quartz crucible manufacturing equipment,this study proposes a design scheme of large-scale quartz crucible feeding frame system with innovative structure,and analyzes the vibration characteristics of this structure in view of the large vibration and instability during operation.In order to study the relationship between the operating vibration and the natural frequency and avoid resonance,the calculated mode was analyzed via ANSYS Workbench,and the experimental mode results were obtained by using percussion test and compared with the calculated mode.It is concluded that the natural frequencies of the first six orders of the large quartz crucible feeding frame are between 5.13 and 23.29,and the main deformation is distributed at the end of the turning mechanism.The analysis results show that the first-order natural frequency of the system has a safety margin of 1.55 times comparing with the working frequency of the drive motor(12 Hz),which effectively avoids the risk of resonance.The feeding frame adopts a double-column truss composite structure,and the layout of the specially designed stiffener network and high-precision guide rails ensures the lightweight structure and significantly improves the dynamic stability of the system.The practical effect of the large-scale quartz crucible feeding frame shows that the structural design is successful,and has reference significance for the structural design of the same type of automatic manufacturing equipment.
文摘BACKGROUND Glaucoma is the leading cause of irreversible blindness worldwide,with 60.5 million affected individuals,of whom 11 million are from India.Due to its asymptomatic nature,the disease largely remains underdiagnosed or diagnosed in advanced stages,where little can be done to salvage functional vision.The literature suggests that a lack of knowledge is one of the reasons for its grave consequences.Assessment of awareness is the first step in planning management.Several studies have been conducted in the Indian community,but data from healthcare providers,who play a significant role in educating the masses directly or indirectly,are limited.AIM To identify awareness,knowledge,and attitudes about glaucoma among healthcare workers in a tertiary center in India.METHODS This cross-sectional study was conducted at a tertiary care institute in Eastern India.Data were collected from 423 participants by systematic stratified sampling after Institutional Ethics Committee approval via a pretested,self-designed,semistructured,validated questionnaire.Statistical analyses were performed using the Statistical Package for Social Sciences Software v22.0.Continuous variables are expressed as the means±SD for parametric values and medians with interquartile ranges for nonparametric values.The associations between the variables were studied via multivariate linear and logistic regression.P<0.05 was considered statistically significant.RESULTS Most respondents were 20–30 years old(n=345,81.6%).The knowledge regarding glaucoma was good,and almost 56.3%of the participants gained knowledge from their medical training.The majority were aware that it has a familial predisposition and is secondary to high intraocular pressure,leading to irreversible peripheral vision loss.Only 42%knew about the life-long requirements of treatment.The resident group scored highest on knowledgeand attitude-based questions,whereas the faculty group scored highest on practice-based questions.Although 62%of the nursing staff had good attitude scores,their knowledge and practice scores were lower.The occupation group response difference was statistically significant(P<0.05)for all the knowledge-based questions.CONCLUSION Although the majority of healthcare providers are aware of glaucoma,there is a dearth of knowledge about treatment modalities.Education via seminars and media can improve their knowledge,attitudes,and practices.
