By deconstructing the dimensions of rural tourism and rural revitalization and constructing a coupled conceptual model,a coupled evaluation model is constructed.Yannanfei Tea Field Resort in Guangdong is taken as a re...By deconstructing the dimensions of rural tourism and rural revitalization and constructing a coupled conceptual model,a coupled evaluation model is constructed.Yannanfei Tea Field Resort in Guangdong is taken as a research case for empirical analysis,to explore the coupled development trend of the two.The results show that①the tourism development of Guangdong Yannanfei Tea Field Resort has a good synergistic relationship with rural revitalization.The two complement and promote each other,and rural tourism has significantly promoted the development of rural revitalization.②The coupling development of tourism development and rural revitalization in Guangdong Yannanfei Tea Field Resort is divided into coupling imbalance period and coupling coordination period.The results indicate that the coordination between the two has not yet reached a level of good coordination and high-quality coordination.It is recommended that the resort should fully utilize the opportunity of rural revitalization strategy,increase investment in rural tourism,promote the transformation and upgrading of the resort,impel the integration of tea and tourism,and develop new business model of tea-tourism rural vacation.展开更多
Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. ...Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. As well, the relation between pore pressure and soil stress was evaluated. The model tests show the vibrations of pore pressure and soil stress as a result of mining activities. The simulation model tells of the response characteristics of pore pressure after mining and its distribution in the sand aquifer. The comparative analysis reveals that pore pressure and soil stress vibration are activated by unexpected events occurring in mines, such as collapsing roofs. An increased pore pressure zone always lies above the wall in front or behind the working face of a mine. Both pore pressure and vertical stress result in increasing and decreasing processes during movements of the working face of a mine. The vibration of pore pressure always precedes soil stress in the same area and ends with a sharp decline. Changes in pore pressure of sand aquifer are limited to the area of stress changes. Obvious changes are largely located in a very small frame over the mining face.展开更多
Secondary structures of RNAs are the basis of understanding their tertiary structures and functions and so their predictions are widely needed due to increasing discovery of noncoding RNAs.In the last decades,a lot of...Secondary structures of RNAs are the basis of understanding their tertiary structures and functions and so their predictions are widely needed due to increasing discovery of noncoding RNAs.In the last decades,a lot of methods have been proposed to predict RNA secondary structures but their accuracies encountered bottleneck.Here we present a method for RNA secondary structure prediction using direct coupling analysis and a remove-and-expand algorithm that shows better performance than four existing popular multiple-sequence methods.We further show that the results can also be used to improve the prediction accuracy of the single-sequence methods.展开更多
In a fusion reactor, the edge localized mode(ELM) coil has a mitigating effect on the ELMs of the plasma. The coil is placed close to the plasma between the vacuum vessel and the blanket to reduce its design power a...In a fusion reactor, the edge localized mode(ELM) coil has a mitigating effect on the ELMs of the plasma. The coil is placed close to the plasma between the vacuum vessel and the blanket to reduce its design power and improve its mitigating ability. The coil works in a high-temperature,high-nuclear-heat and high-magnetic-field environment. Due to the existence of outer superconducting coils, the coil is subjected to an alternating electromagnetic force induced by its own alternating current and the outer magnetic field. The design goal for the ELM coil is to maintain its structural integrity in the multi-physical field. Taking as an example the middle ELM coil(with flexible supports) of ITER(the International Thermonuclear Fusion Reactor), an electromagnetic–thermal–structural coupling analysis is carried out using ANSYS. The results show that the flexible supports help the three-layer casing meet the static and fatigue design requirements. The structural design of the middle ELM coil is reasonable and feasible. The work described in this paper provides the theoretical basis and method for ELM coil design.展开更多
Analyzing the sustainable development of a given region can provide an important reference and guide for future orientation.The study selects Turpan(including Gaochang District,Shanshan County,and Toksun County)in Xin...Analyzing the sustainable development of a given region can provide an important reference and guide for future orientation.The study selects Turpan(including Gaochang District,Shanshan County,and Toksun County)in Xinjiang Uygur Autonomous Region of Northwest China as the study area and first investigates the essence of regional sustainable development.Based on the relevant data of the population,economy,and environment of Turpan from 2002 to 2018,we constructed an evaluation index system for three dimensions,namely,the population,economy,and environment,and analyzed them systematically.Specifically,we quantitatively calculated the comprehensive evaluation index,coupling degree,and coupling coordination degree of the sustainable development system of the study area.The study finds that Turpan has become increasingly sustainable and orderly;the development level has continually improved from near imbalance to positive coordination.During the study period,the government has adopted appropriate models and paths to promote positive interactions among the population,economy,and environment based on engineering techniques and ecological means.The results show that the coupling coordination degree has increased from 0.3692 to 0.8894 during the period 2002–2018,which reflects the actual situation of Turpan and indicates that the proposed analysis method can effectively measure and evaluate the level of sustainable development in this region.Moreover,the study also puts forward main functional zoning of Turpan(i.e.,Gaochang District as an optimized development zone,Shanshan County as a major agricultural production zone,and Toksun County as a key ecological function zone)and regional planning principles based on the population,economic,and environmental coupling analysis for the three jurisdictions in Turpan.展开更多
Coupling analysis of passenger and train flows is an important approach in evaluating and optimizing the operation efficiency of large-scale urban rail transit(URT)systems.This study proposes a passenger–train intera...Coupling analysis of passenger and train flows is an important approach in evaluating and optimizing the operation efficiency of large-scale urban rail transit(URT)systems.This study proposes a passenger–train interaction simulation approach to determine the coupling relationship between passenger and train flows.On the bases of time-varying origin–destination demand,train timetable,and network topology,the proposed approach can restore passenger behaviors in URT systems.Upstream priority,queuing process with first-in-first-serve principle,and capacity constraints are considered in the proposed simulation mechanism.This approach can also obtain each passenger’s complete travel chain,which can be used to analyze(including but not limited to)various indicators discussed in this research to effectively support train schedule optimization and capacity evaluation for urban rail managers.Lastly,the proposed model and its potential application are demonstrated via numerical experiments using real-world data from the Beijing URT system(i.e.,rail network with the world’s highest passenger ridership).展开更多
Aiming at the problem that it is difficult to obtain the explicit expression of the structural matrix in the traditional train-bridge coupling vibration analysis,a combined simulation system of train-bridge coupling s...Aiming at the problem that it is difficult to obtain the explicit expression of the structural matrix in the traditional train-bridge coupling vibration analysis,a combined simulation system of train-bridge coupling system(TBCS)under earthquake(MAETB)is developed based on the cooperative work of MATLAB and ANSYS.The simulation system is used to analyze the dynamic parameters of the TBCS of a prestressed concrete continuous rigid frame bridge benchmark model of a heavy-haul railway.The influence of different driving speeds,seismic wave intensities,and traveling wave effects on the dynamic response of the TBCS under the actions of the earthquakes is discussed.The results show that the bridge displacement increase in magnitude in the lateral direction is more significant than in the vertical direction under the action of an earthquake.The traveling wave effect can significantly reduce the lateral response of the bridge,but it will significantly increase the train derailment coefficient.When the earthquake intensity exceeds 0.2 g,the partial derailment coefficient of the train has exceeded the limit value of the specification.展开更多
Design of a very large floating structure(VLFS)deployed near islands and reefs,different from those in the open sea,inevitably faces new technical challenges including numerical analysis methods.In this paper,a direct...Design of a very large floating structure(VLFS)deployed near islands and reefs,different from those in the open sea,inevitably faces new technical challenges including numerical analysis methods.In this paper,a direct coupling analysis method(DCAM)has been established based on the Boussinesq equations and the three-dimensional hydroelasisity theory with Rankine source method to analyze the responses of a VLFS in shallow sea with complicated geographical environment.Model tests have been carried out to validate the DCAM.To further verify the numerical methods and investigate the performance of such a VLFS,a“Scientific Research and Demonstration Platform(SRDP)”was built and deployed in 2019 at the site about 1000 m off an island with water depth around 40m in South China Sea.It is a simplified small model of a two-module semi-submersible-type VLFS.The numerical simulation of its responses on severe waves with focus on motions and connector forces is conduct by DCAM,and compared with the on-site measurements.Good agreement has been achieved.This approves the DCAM as a feasible tool for design and safety assessment of a VLFS deployed near islands and reefs.展开更多
False monitoring information is a major problem in process production system and several ineffective methods have been proposed to identify false monitoring information in the production system. In this paper, a new m...False monitoring information is a major problem in process production system and several ineffective methods have been proposed to identify false monitoring information in the production system. In this paper, a new method is proposed to identify false monitoring information based on system coupling analysis and collision detection from the perspective of data analysis. Coupling multifractal features are extracted to reflect the changes in coupling relationship by utilizing the multifractal detrended cross-correlation analysis (MF-DXA). Each monitoring variable in process production system has more than one coupled variable, which can be regarded as multi-source. To achieve low redundancy in features and uniform description of coupling relationship, the feature level information fusion is studied based on modified Mahalanobis Taguchi system (MTS). False alarms are identified when the coupling relationships among the coupled monitoring variables collide. Analysis results of coupled R?ssler and Henon datasets indicate the feasibility of this method for selecting the effective coupling feature and uniform description of coupling relationship. The compressor system case of Coal Chemical Ltd. Group is studied and false monitoring information is identified.展开更多
From the perspective of the National Social Science Fund projects,this paper explored a new way to research on the interdisciplinarity,so as to improve the understanding of interdisciplinarity and its evolutionary cha...From the perspective of the National Social Science Fund projects,this paper explored a new way to research on the interdisciplinarity,so as to improve the understanding of interdisciplinarity and its evolutionary characteristics in the domain of Library and Information Science(LIS).Based on the keywords extracted from the titles of the National Social Science Fund projects approved in the past ten years,this paper calculated the interdisciplinary degree and detected the intersections between LIS and other 22 disciplines by means of keywords coupling analysis,to reveal the evolutionary characteristics in the past ten years and investigate the evolution forms and mechanism.LIS has a strong interdisciplinary degree which is showing an increasing trend.The interdisciplinary and openness of LIS are the fundamental driving force of interdisciplinarity.Its interdisciplinarity is mainly manifested in the adherence to the discipline core and the expansion of the discipline edge.In the process of interdisciplinarity,LIS also has the problem of insufficient influence and penetration.展开更多
A periodic pipe system composed of steel pipes and rubber hoses with the same inner radius is designed based on the theory of phononic crystals. Using the transfer matrix method, the band structure of the periodic pip...A periodic pipe system composed of steel pipes and rubber hoses with the same inner radius is designed based on the theory of phononic crystals. Using the transfer matrix method, the band structure of the periodic pipe is calculated considering the structural-acoustic coupling. The results show that longitudinal vibration band gaps and acoustic band gaps can coexist in the fluid-filled periodic pipe. The formation of the band gap mechanism is further analyzed. The band gaps are validated by the sound transmission loss and vibration-frequency response functions calculated using the finite element method. The effect of the damp on the band gap is analyzed by calculating the complex band structure. The periodic pipe system can be used not only in the field of vibration reduction but also for noise elimination.展开更多
The quantum chromodynamics(QCD) coupling αs is the most important parameter for achieving precise QCD predictions. By using the well measured effective coupling α_(s)^(g)1)(Q) defined from the Bjorken sum rules as a...The quantum chromodynamics(QCD) coupling αs is the most important parameter for achieving precise QCD predictions. By using the well measured effective coupling α_(s)^(g)1)(Q) defined from the Bjorken sum rules as a basis, we suggest a novel self-consistency way to fix the αs at all scales: The QCD light-front holographic model is adopted for its infrared behavior, and the fixed-order p QCD prediction under the principle of maximum conformality(PMC) is used for its high-energy behavior. Using the PMC scheme-and-scale independent perturbative series,and by transforming it into the one under the physical V scheme, we observe that a precise αs running behavior in both the perturbative and nonperturbative domains with a smooth transition from small to large scales can be achieved.展开更多
Purpose–This study aims to propose a vertical coupling dynamic analysis method of vehicle–track–substructure based on forced vibration and use this method to analyze the influence on the dynamic response of track a...Purpose–This study aims to propose a vertical coupling dynamic analysis method of vehicle–track–substructure based on forced vibration and use this method to analyze the influence on the dynamic response of track and vehicle caused by local fastener failure.Design/methodology/approach–The track and substructure are decomposed into the rail subsystem and substructure subsystem,in which the rail subsystem is composed of two layers of nodes corresponding to the upper rail and the lower fastener.The rail is treated as a continuous beam with elastic discrete point supports,and spring-damping elements are used to simulate the constraints between rail and fastener.Forced displacement and forced velocity are used to deal with the effect of the substructure on the rail system,while the external load is used to deal with the reverse effect.The fastener failure is simulated with the methods that cancel the forced vibration transmission,namely take no account of the substructure–rail interaction at that position.Findings–The dynamic characteristics of the infrastructure with local diseases can be accurately calculated by using the proposed method.Local fastener failure will slightly affect the vibration of substructure and carbody,but it will significantly intensify the vibration response between wheel and rail.The maximum vertical displacement and the maximum vertical vibration acceleration of rail is 2.94 times and 2.97 times the normal value,respectively,under the train speed of 350 km$h1.At the same time,the maximum wheel–rail force and wheel load reduction rate increase by 22.0 and 50.2%,respectively,from the normal value.Originality/value–This method can better reveal the local vibration conditions of the rail and easily simulate the influence of various defects on the dynamic response of the coupling system.展开更多
Vibration quality is a vital indicator for assessing the progress of modern equipment.The dynamic vibration absorber(DVA)based on the acoustic black hole(ABH)feature is a new passive control method that manipulates wa...Vibration quality is a vital indicator for assessing the progress of modern equipment.The dynamic vibration absorber(DVA)based on the acoustic black hole(ABH)feature is a new passive control method that manipulates waves.It offers efficient energy focalization and broad-spectrum vibration suppression,making it highly promising for applications in large equipment such as aircraft,trains,and ships.Despite previous advancements in ABH-DVA development,certain challenges remain,particularly in ensuring effective coupling with host structures during control.To address these issues,this study proposes a partitioned ABH-featured dynamic vibration absorber(PABH-DVA)with partitions in the radial direction of the disc.By employing a plate as the host structure,simulations and experiments were conducted,demonstrating that the PABH-DVA outperforms the original symmetric ABH-DVA in terms of damping performance.The study also calculated and compared the coupling coefficients of the two ABH-DVAs to uncover the mechanism behind the enhanced damping.Simulation results revealed that the PABH-DVA exhibits more coupled modes,occasionally with lower coupling coefficients than the symmetric ABH-DVA.The influence of frequency ratio and modal mass was further analyzed to explain the reasons behind the PABH-DVA's superior damping performance.Additionally,the study discussed the impact of the number of slits and their orientation.This research further explains the coupling mechanism between the ABH-DVA and the controlled structure,and provides new ideas for the further application of ABH in engineering.展开更多
Laying the under-sleeper pad(USP)is one of the effective measures commonly used to delay ballast degradation and reduce maintenance workload.To explore the impact of application of the USP on the dynamic and static me...Laying the under-sleeper pad(USP)is one of the effective measures commonly used to delay ballast degradation and reduce maintenance workload.To explore the impact of application of the USP on the dynamic and static mechanical behavior of the ballast track in the heavy-haul railway system,numerical simulation models of the ballast bed with USP and without USP are presented in this paper by using the discrete element method(DEM)-multi-flexible body dynamic(MFBD)coupling analysis method.The ballast bed support stiffness test and dynamic displacement tests were carried out on the actual operation of a heavy-haul railway line to verify the validity of the models.The results show that using the USP results in a 43.01%reduction in the ballast bed support stiffness and achieves a more uniform distribution of track loads on the sleepers.It effectively reduces the load borne by the sleeper directly under the wheel load,with a 7.89%reduction in the pressure on the sleeper.Furthermore,the laying of the USP changes the lateral resistance sharing ratio of the ballast bed,significantly reducing the stress level of the ballast bed under train loads,with an average stress reduction of 42.19 kPa.It also reduces the plastic displacement of ballast particles and lowers the peak value of rotational angular velocity by about 50%to 70%,which is conducive to slowing down ballast bed settlement deformation and reducing maintenance costs.In summary,laying the USP has a potential value in enhancing the stability and extending the lifespan of the ballast bed in heavy-haul railway systems.展开更多
Based on the construction interfaces in rolled control concrete dam(RCCD), the methods were proposed to calculate the influence thickness of construction interfaces and the corresponding physical mechanics parameters....Based on the construction interfaces in rolled control concrete dam(RCCD), the methods were proposed to calculate the influence thickness of construction interfaces and the corresponding physical mechanics parameters. The principle on establishing the coupling model of seepage_field and stress_field for RCCD was presented. A 3_D Finite Element Method(FEM) program was developed. Study shows that such parameters as the thickness of construction interfaces,the elastic ratio and the (Poisson's) ratio obtained by tests and theoretical analysis are more reasonable, the coupling model of seepage_field and stress_field for RCCD may indicate the coupling effect between the two fields scientifically, and the developed 3_D FEM program can reflect the effect of the construction interfaces more adequately. According to the study, many scientific opinions are given both to analyze the influence of the construction interfaces to the (dam's) characteristic, and to reveal the interaction between the stress_field and the seepage_field.展开更多
The trade-offs and supply-demand relations of ecosystem services(ES)are at the frontier of geographical and ecological studies.However,previous studies have focused on either trade-offs or the supply-demand aspects,wh...The trade-offs and supply-demand relations of ecosystem services(ES)are at the frontier of geographical and ecological studies.However,previous studies have focused on either trade-offs or the supply-demand aspects,while ES conflicts and supply/demand contradictions have not been comprehensively examined.The relation-ship between ES trade-offs and supply-demand is logically valid and studying the coupling of both can provide approaches for simultaneously alleviating ES conflicts and supply-demand contradictions.This study,based on a review of previous analyses of ES trade-offs and supply-demand dynamics,proposes a new analytic framework to couple them.First,we define two types of trade-offs based on the directions of growth or decline of the two ser-vices.We also define the supply-demand balance area and the supply-demand risk area according to the ES flow characteristics.Second,the mechanisms driving ES trade-offs are clarified,and land-use scenarios are set based on the mechanisms.Third,the supply-demand spatial characteristics of ES are analyzed,and supply-demand risk areas are identified.Finally,scenario iterations are performed to minimize the supply-demand risk area at an acceptable trade-offintensity to identify an optimal land use plan,which simultaneously alleviates ES conflicts and supply-demand contradictions.This analytic framework offers new opportunities for improving sustainable ecosystem management.展开更多
Rock shed is an effective protection measure against rockfall.To investigate the influences of falling rock’s shape and impact angle on the impact effect of the cushioned rock shed,a modeling approach for a rock shed...Rock shed is an effective protection measure against rockfall.To investigate the influences of falling rock’s shape and impact angle on the impact effect of the cushioned rock shed,a modeling approach for a rock shed with a cushion layer using PFC-FLAC.The granular cushion is modeled as an aggregate of discrete non-cohesion particles,while the concrete plate and the beam are modeled as zones.The falling rock with different sphericities and impact angles is modeled as a rigid assembly.The numerical model is validated by comparing the simulation results with experimental and numerical results from previous literature.This model is applied to analyze the effects of rock shape and impact angle on the dynamic interaction effects between falling rock and cushioned rock shed,including the impact force,transmitted bottom force,penetration depth,and plate deflection.The numerical results show that the variation in the falling rock’s shape has different effects on the falling rock with different impact angles.These findings could support rock shed design by revealing the limitations of the assumptions in the past research,which may result in unsafe rock sheds for some rockfall cases.展开更多
Finite element (FE) coupled thermal-mechanical analysis is widely used to predict the deformation and residualstress of wire arc additive manufacturing (WAAM) parts. In this study, an innovative single-layermulti-bead...Finite element (FE) coupled thermal-mechanical analysis is widely used to predict the deformation and residualstress of wire arc additive manufacturing (WAAM) parts. In this study, an innovative single-layermulti-bead profilegeometric modeling method through the isosceles trapezoid function is proposed to build the FE model of theWAAMprocess. Firstly, a straight-line model for overlapping beads based on the parabola function was establishedto calculate the optimal center distance. Then, the isosceles trapezoid-based profile was employed to replace theparabola profiles of the parabola-based overlapping model to establish an innovative isosceles trapezoid-basedmulti-bead overlapping geometric model. The rationality of the isosceles trapezoid-based overlapping model wasconfirmed by comparing the geometric deviation and the heat dissipation performance index of the two overlappingmodels. In addition, the FE-coupled thermal-mechanical analysis, as well as a comparative experiment of thesingle-layer eight-bead deposition process show that the simulation results of the above two models agree with theexperimental results. At the same time, the proposed isosceles trapezoid-based overlappingmodels are all straightlineprofiles, which can be divided into high-quality FE elements. It can improve the modeling efficiency andshorten the simulation calculation time. The innovative modeling method proposed in this study can provide anefficient and high-precision geometricmodelingmethod forWAAMpart FE coupled thermal-mechanical analysis.展开更多
The Southern Ocean is an important carbon sink pool and plays a critical role in the global carbon cycling.The Amundsen Sea was reported to be highly productive in inshore area in the Southern Ocean.In order to invest...The Southern Ocean is an important carbon sink pool and plays a critical role in the global carbon cycling.The Amundsen Sea was reported to be highly productive in inshore area in the Southern Ocean.In order to investigate the influence of transparent exopolymer particles(TEP)on the behavior of dissolved organic carbon(DOC)in this region,a comprehensive study was conducted,encompassing both open water areas and highly productive polynyas.It was found that microbial heterotrophic metabolism is the primary process responsible for the production of humic-like fluorescent components in the open ocean.The relationship between apparent oxygen utilization and the two humic-like components can be accurately described by a power-law function,with a conversion rate consistent with that observed globally.The presence of TEP was found to have little impact on this process.Additionally,the study revealed the accumulation of DOC at the sea surface in the Amundsen Sea Polynya,suggesting that TEP may play a critical role in this phenomenon.These findings contribute to a deeper understanding of the dynamics and surface accumulation of DOC in the Amundsen Sea Polynya,and provide valuable insights into the carbon cycle in this region.展开更多
基金Sponsored by Zhaoqing University Students Entrepreneurship Training Program Project(X202310580167).
文摘By deconstructing the dimensions of rural tourism and rural revitalization and constructing a coupled conceptual model,a coupled evaluation model is constructed.Yannanfei Tea Field Resort in Guangdong is taken as a research case for empirical analysis,to explore the coupled development trend of the two.The results show that①the tourism development of Guangdong Yannanfei Tea Field Resort has a good synergistic relationship with rural revitalization.The two complement and promote each other,and rural tourism has significantly promoted the development of rural revitalization.②The coupling development of tourism development and rural revitalization in Guangdong Yannanfei Tea Field Resort is divided into coupling imbalance period and coupling coordination period.The results indicate that the coordination between the two has not yet reached a level of good coordination and high-quality coordination.It is recommended that the resort should fully utilize the opportunity of rural revitalization strategy,increase investment in rural tourism,promote the transformation and upgrading of the resort,impel the integration of tea and tourism,and develop new business model of tea-tourism rural vacation.
基金Project supported by Qing Lan Project of Jiangsu, China
文摘Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. As well, the relation between pore pressure and soil stress was evaluated. The model tests show the vibrations of pore pressure and soil stress as a result of mining activities. The simulation model tells of the response characteristics of pore pressure after mining and its distribution in the sand aquifer. The comparative analysis reveals that pore pressure and soil stress vibration are activated by unexpected events occurring in mines, such as collapsing roofs. An increased pore pressure zone always lies above the wall in front or behind the working face of a mine. Both pore pressure and vertical stress result in increasing and decreasing processes during movements of the working face of a mine. The vibration of pore pressure always precedes soil stress in the same area and ends with a sharp decline. Changes in pore pressure of sand aquifer are limited to the area of stress changes. Obvious changes are largely located in a very small frame over the mining face.
基金Project supported by the National Natural Science Foundation of China(Grant No.31570722).
文摘Secondary structures of RNAs are the basis of understanding their tertiary structures and functions and so their predictions are widely needed due to increasing discovery of noncoding RNAs.In the last decades,a lot of methods have been proposed to predict RNA secondary structures but their accuracies encountered bottleneck.Here we present a method for RNA secondary structure prediction using direct coupling analysis and a remove-and-expand algorithm that shows better performance than four existing popular multiple-sequence methods.We further show that the results can also be used to improve the prediction accuracy of the single-sequence methods.
基金the Province Postdoctoral Foundation of Jiangsu(1501164B)the Technical Innovation Nurturing Foundation of Yangzhou University(2015CXJ016)China Postdoctoral Science Foundation(2016M600447)
文摘In a fusion reactor, the edge localized mode(ELM) coil has a mitigating effect on the ELMs of the plasma. The coil is placed close to the plasma between the vacuum vessel and the blanket to reduce its design power and improve its mitigating ability. The coil works in a high-temperature,high-nuclear-heat and high-magnetic-field environment. Due to the existence of outer superconducting coils, the coil is subjected to an alternating electromagnetic force induced by its own alternating current and the outer magnetic field. The design goal for the ELM coil is to maintain its structural integrity in the multi-physical field. Taking as an example the middle ELM coil(with flexible supports) of ITER(the International Thermonuclear Fusion Reactor), an electromagnetic–thermal–structural coupling analysis is carried out using ANSYS. The results show that the flexible supports help the three-layer casing meet the static and fatigue design requirements. The structural design of the middle ELM coil is reasonable and feasible. The work described in this paper provides the theoretical basis and method for ELM coil design.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20060303),the“Light of West China”Program of the Chinese Academy of Sciences(2018-XBQNXZ-B-017),and the“High-Level Talents Project”in Xinjiang(Y942171).Data collection and analysis are supported by the Sino-German Joint Research Center for the Management of Ecosystems and Environmental Changes in Arid Lands and the Research Center for Ecology and Environment of Central Asia of the Chinese Academy of Sciences.Special thanks are given to the support of the“One Hundred Person Project”of the Chinese Academy of Sciences(Y931201).
文摘Analyzing the sustainable development of a given region can provide an important reference and guide for future orientation.The study selects Turpan(including Gaochang District,Shanshan County,and Toksun County)in Xinjiang Uygur Autonomous Region of Northwest China as the study area and first investigates the essence of regional sustainable development.Based on the relevant data of the population,economy,and environment of Turpan from 2002 to 2018,we constructed an evaluation index system for three dimensions,namely,the population,economy,and environment,and analyzed them systematically.Specifically,we quantitatively calculated the comprehensive evaluation index,coupling degree,and coupling coordination degree of the sustainable development system of the study area.The study finds that Turpan has become increasingly sustainable and orderly;the development level has continually improved from near imbalance to positive coordination.During the study period,the government has adopted appropriate models and paths to promote positive interactions among the population,economy,and environment based on engineering techniques and ecological means.The results show that the coupling coordination degree has increased from 0.3692 to 0.8894 during the period 2002–2018,which reflects the actual situation of Turpan and indicates that the proposed analysis method can effectively measure and evaluate the level of sustainable development in this region.Moreover,the study also puts forward main functional zoning of Turpan(i.e.,Gaochang District as an optimized development zone,Shanshan County as a major agricultural production zone,and Toksun County as a key ecological function zone)and regional planning principles based on the population,economic,and environmental coupling analysis for the three jurisdictions in Turpan.
基金This research was supported by the National Key R&D Program of China(Grant No.2020YFB1600702)the National Natural Science Foundation of China(Grant Nos.71621001,72071015,71701013,and 71890972/71890970)+2 种基金the Beijing Municipal Natural Science Foundation(Grant No.L191024)the 111 Project(Grant No.B20071)the State Key Laboratory of Rail Traffic Control and Safety(Grant No.RCS2021ZZ001).
文摘Coupling analysis of passenger and train flows is an important approach in evaluating and optimizing the operation efficiency of large-scale urban rail transit(URT)systems.This study proposes a passenger–train interaction simulation approach to determine the coupling relationship between passenger and train flows.On the bases of time-varying origin–destination demand,train timetable,and network topology,the proposed approach can restore passenger behaviors in URT systems.Upstream priority,queuing process with first-in-first-serve principle,and capacity constraints are considered in the proposed simulation mechanism.This approach can also obtain each passenger’s complete travel chain,which can be used to analyze(including but not limited to)various indicators discussed in this research to effectively support train schedule optimization and capacity evaluation for urban rail managers.Lastly,the proposed model and its potential application are demonstrated via numerical experiments using real-world data from the Beijing URT system(i.e.,rail network with the world’s highest passenger ridership).
基金funded by the Open Projects Foundation of Engineering Research Center of Disaster Prevention and Mitigation of Southeast Coastal Engineering Structures of Fujian Province University(Grant No.2022009)the National Natural Science Foundation of China(Grant No.51708429)the Construction Science and Technology Plan Projects of Hubei Province(Grant No.2023011).
文摘Aiming at the problem that it is difficult to obtain the explicit expression of the structural matrix in the traditional train-bridge coupling vibration analysis,a combined simulation system of train-bridge coupling system(TBCS)under earthquake(MAETB)is developed based on the cooperative work of MATLAB and ANSYS.The simulation system is used to analyze the dynamic parameters of the TBCS of a prestressed concrete continuous rigid frame bridge benchmark model of a heavy-haul railway.The influence of different driving speeds,seismic wave intensities,and traveling wave effects on the dynamic response of the TBCS under the actions of the earthquakes is discussed.The results show that the bridge displacement increase in magnitude in the lateral direction is more significant than in the vertical direction under the action of an earthquake.The traveling wave effect can significantly reduce the lateral response of the bridge,but it will significantly increase the train derailment coefficient.When the earthquake intensity exceeds 0.2 g,the partial derailment coefficient of the train has exceeded the limit value of the specification.
基金supported by the Ministry of Industry and Information Technology(Grant Nos.[2016]22,[2019]357)the Ministry of Science and Technology(Grant No.2013CB36102)+1 种基金supported by the National KeyResearch and Development Program of China(Grant No.2017YFBO202701)the Jiangsu Province ScienceFoundation for Youths(BK20190151).
文摘Design of a very large floating structure(VLFS)deployed near islands and reefs,different from those in the open sea,inevitably faces new technical challenges including numerical analysis methods.In this paper,a direct coupling analysis method(DCAM)has been established based on the Boussinesq equations and the three-dimensional hydroelasisity theory with Rankine source method to analyze the responses of a VLFS in shallow sea with complicated geographical environment.Model tests have been carried out to validate the DCAM.To further verify the numerical methods and investigate the performance of such a VLFS,a“Scientific Research and Demonstration Platform(SRDP)”was built and deployed in 2019 at the site about 1000 m off an island with water depth around 40m in South China Sea.It is a simplified small model of a two-module semi-submersible-type VLFS.The numerical simulation of its responses on severe waves with focus on motions and connector forces is conduct by DCAM,and compared with the on-site measurements.Good agreement has been achieved.This approves the DCAM as a feasible tool for design and safety assessment of a VLFS deployed near islands and reefs.
基金supported by the National Natural Science Foundation of China (Grant No. 51375375)
文摘False monitoring information is a major problem in process production system and several ineffective methods have been proposed to identify false monitoring information in the production system. In this paper, a new method is proposed to identify false monitoring information based on system coupling analysis and collision detection from the perspective of data analysis. Coupling multifractal features are extracted to reflect the changes in coupling relationship by utilizing the multifractal detrended cross-correlation analysis (MF-DXA). Each monitoring variable in process production system has more than one coupled variable, which can be regarded as multi-source. To achieve low redundancy in features and uniform description of coupling relationship, the feature level information fusion is studied based on modified Mahalanobis Taguchi system (MTS). False alarms are identified when the coupling relationships among the coupled monitoring variables collide. Analysis results of coupled R?ssler and Henon datasets indicate the feasibility of this method for selecting the effective coupling feature and uniform description of coupling relationship. The compressor system case of Coal Chemical Ltd. Group is studied and false monitoring information is identified.
基金funded by the National Social Science Foundation of China(No.20BTQ089)
文摘From the perspective of the National Social Science Fund projects,this paper explored a new way to research on the interdisciplinarity,so as to improve the understanding of interdisciplinarity and its evolutionary characteristics in the domain of Library and Information Science(LIS).Based on the keywords extracted from the titles of the National Social Science Fund projects approved in the past ten years,this paper calculated the interdisciplinary degree and detected the intersections between LIS and other 22 disciplines by means of keywords coupling analysis,to reveal the evolutionary characteristics in the past ten years and investigate the evolution forms and mechanism.LIS has a strong interdisciplinary degree which is showing an increasing trend.The interdisciplinary and openness of LIS are the fundamental driving force of interdisciplinarity.Its interdisciplinarity is mainly manifested in the adherence to the discipline core and the expansion of the discipline edge.In the process of interdisciplinarity,LIS also has the problem of insufficient influence and penetration.
基金Supported by the National Natural Science Foundation of China under Grant No 11372346
文摘A periodic pipe system composed of steel pipes and rubber hoses with the same inner radius is designed based on the theory of phononic crystals. Using the transfer matrix method, the band structure of the periodic pipe is calculated considering the structural-acoustic coupling. The results show that longitudinal vibration band gaps and acoustic band gaps can coexist in the fluid-filled periodic pipe. The formation of the band gap mechanism is further analyzed. The band gaps are validated by the sound transmission loss and vibration-frequency response functions calculated using the finite element method. The effect of the damp on the band gap is analyzed by calculating the complex band structure. The periodic pipe system can be used not only in the field of vibration reduction but also for noise elimination.
基金supported in part by the Chongqing Graduate Research and Innovation Foundation (Grant Nos. CYB21045 and ydstd1912)the National Natural Science Foundation of China (Grant Nos. 11905056, 12175025, and 12147102)the Fundamental Research Funds for the Central Universities (Grant No. 2020CQJQYZ003)。
文摘The quantum chromodynamics(QCD) coupling αs is the most important parameter for achieving precise QCD predictions. By using the well measured effective coupling α_(s)^(g)1)(Q) defined from the Bjorken sum rules as a basis, we suggest a novel self-consistency way to fix the αs at all scales: The QCD light-front holographic model is adopted for its infrared behavior, and the fixed-order p QCD prediction under the principle of maximum conformality(PMC) is used for its high-energy behavior. Using the PMC scheme-and-scale independent perturbative series,and by transforming it into the one under the physical V scheme, we observe that a precise αs running behavior in both the perturbative and nonperturbative domains with a smooth transition from small to large scales can be achieved.
基金funded by the Research Fund of Shanghai Bureau Group Corporation(2021142)Science Foundation of China State Railway Group Corporation Limited(P2021T013)and Science Foundation of China Academy of Railway Sciences Corporation Limited(2021YJ250).
文摘Purpose–This study aims to propose a vertical coupling dynamic analysis method of vehicle–track–substructure based on forced vibration and use this method to analyze the influence on the dynamic response of track and vehicle caused by local fastener failure.Design/methodology/approach–The track and substructure are decomposed into the rail subsystem and substructure subsystem,in which the rail subsystem is composed of two layers of nodes corresponding to the upper rail and the lower fastener.The rail is treated as a continuous beam with elastic discrete point supports,and spring-damping elements are used to simulate the constraints between rail and fastener.Forced displacement and forced velocity are used to deal with the effect of the substructure on the rail system,while the external load is used to deal with the reverse effect.The fastener failure is simulated with the methods that cancel the forced vibration transmission,namely take no account of the substructure–rail interaction at that position.Findings–The dynamic characteristics of the infrastructure with local diseases can be accurately calculated by using the proposed method.Local fastener failure will slightly affect the vibration of substructure and carbody,but it will significantly intensify the vibration response between wheel and rail.The maximum vertical displacement and the maximum vertical vibration acceleration of rail is 2.94 times and 2.97 times the normal value,respectively,under the train speed of 350 km$h1.At the same time,the maximum wheel–rail force and wheel load reduction rate increase by 22.0 and 50.2%,respectively,from the normal value.Originality/value–This method can better reveal the local vibration conditions of the rail and easily simulate the influence of various defects on the dynamic response of the coupling system.
基金Supported by National Key Research and Development Program of China (Grant No.2021YFB3400100)National Natural Science Foundation of China (Grant Nos.52241103,U2241261,52022039)。
文摘Vibration quality is a vital indicator for assessing the progress of modern equipment.The dynamic vibration absorber(DVA)based on the acoustic black hole(ABH)feature is a new passive control method that manipulates waves.It offers efficient energy focalization and broad-spectrum vibration suppression,making it highly promising for applications in large equipment such as aircraft,trains,and ships.Despite previous advancements in ABH-DVA development,certain challenges remain,particularly in ensuring effective coupling with host structures during control.To address these issues,this study proposes a partitioned ABH-featured dynamic vibration absorber(PABH-DVA)with partitions in the radial direction of the disc.By employing a plate as the host structure,simulations and experiments were conducted,demonstrating that the PABH-DVA outperforms the original symmetric ABH-DVA in terms of damping performance.The study also calculated and compared the coupling coefficients of the two ABH-DVAs to uncover the mechanism behind the enhanced damping.Simulation results revealed that the PABH-DVA exhibits more coupled modes,occasionally with lower coupling coefficients than the symmetric ABH-DVA.The influence of frequency ratio and modal mass was further analyzed to explain the reasons behind the PABH-DVA's superior damping performance.Additionally,the study discussed the impact of the number of slits and their orientation.This research further explains the coupling mechanism between the ABH-DVA and the controlled structure,and provides new ideas for the further application of ABH in engineering.
基金the project supported by the National Natural Science Foundation of China(Grant No.52372425)the Fundamental Research Funds for the Central Universities(Science and technology leading talent team project)(Grant No.2022JBXT010).
文摘Laying the under-sleeper pad(USP)is one of the effective measures commonly used to delay ballast degradation and reduce maintenance workload.To explore the impact of application of the USP on the dynamic and static mechanical behavior of the ballast track in the heavy-haul railway system,numerical simulation models of the ballast bed with USP and without USP are presented in this paper by using the discrete element method(DEM)-multi-flexible body dynamic(MFBD)coupling analysis method.The ballast bed support stiffness test and dynamic displacement tests were carried out on the actual operation of a heavy-haul railway line to verify the validity of the models.The results show that using the USP results in a 43.01%reduction in the ballast bed support stiffness and achieves a more uniform distribution of track loads on the sleepers.It effectively reduces the load borne by the sleeper directly under the wheel load,with a 7.89%reduction in the pressure on the sleeper.Furthermore,the laying of the USP changes the lateral resistance sharing ratio of the ballast bed,significantly reducing the stress level of the ballast bed under train loads,with an average stress reduction of 42.19 kPa.It also reduces the plastic displacement of ballast particles and lowers the peak value of rotational angular velocity by about 50%to 70%,which is conducive to slowing down ballast bed settlement deformation and reducing maintenance costs.In summary,laying the USP has a potential value in enhancing the stability and extending the lifespan of the ballast bed in heavy-haul railway systems.
文摘Based on the construction interfaces in rolled control concrete dam(RCCD), the methods were proposed to calculate the influence thickness of construction interfaces and the corresponding physical mechanics parameters. The principle on establishing the coupling model of seepage_field and stress_field for RCCD was presented. A 3_D Finite Element Method(FEM) program was developed. Study shows that such parameters as the thickness of construction interfaces,the elastic ratio and the (Poisson's) ratio obtained by tests and theoretical analysis are more reasonable, the coupling model of seepage_field and stress_field for RCCD may indicate the coupling effect between the two fields scientifically, and the developed 3_D FEM program can reflect the effect of the construction interfaces more adequately. According to the study, many scientific opinions are given both to analyze the influence of the construction interfaces to the (dam's) characteristic, and to reveal the interaction between the stress_field and the seepage_field.
基金This research was funded by the National Natural Science Foun-dation of China(Grant No.41861134038,41771197)Norwegian Re-search Council(Grant No.286773)the Fundamental Research Funds for the Central Universities,and Fundamental Research Program of Shanxi Province(Grant No.20210302123481).
文摘The trade-offs and supply-demand relations of ecosystem services(ES)are at the frontier of geographical and ecological studies.However,previous studies have focused on either trade-offs or the supply-demand aspects,while ES conflicts and supply/demand contradictions have not been comprehensively examined.The relation-ship between ES trade-offs and supply-demand is logically valid and studying the coupling of both can provide approaches for simultaneously alleviating ES conflicts and supply-demand contradictions.This study,based on a review of previous analyses of ES trade-offs and supply-demand dynamics,proposes a new analytic framework to couple them.First,we define two types of trade-offs based on the directions of growth or decline of the two ser-vices.We also define the supply-demand balance area and the supply-demand risk area according to the ES flow characteristics.Second,the mechanisms driving ES trade-offs are clarified,and land-use scenarios are set based on the mechanisms.Third,the supply-demand spatial characteristics of ES are analyzed,and supply-demand risk areas are identified.Finally,scenario iterations are performed to minimize the supply-demand risk area at an acceptable trade-offintensity to identify an optimal land use plan,which simultaneously alleviates ES conflicts and supply-demand contradictions.This analytic framework offers new opportunities for improving sustainable ecosystem management.
基金supported by the National Natural Science Foundation of China(Grant Nos.41941017 and U1702241).
文摘Rock shed is an effective protection measure against rockfall.To investigate the influences of falling rock’s shape and impact angle on the impact effect of the cushioned rock shed,a modeling approach for a rock shed with a cushion layer using PFC-FLAC.The granular cushion is modeled as an aggregate of discrete non-cohesion particles,while the concrete plate and the beam are modeled as zones.The falling rock with different sphericities and impact angles is modeled as a rigid assembly.The numerical model is validated by comparing the simulation results with experimental and numerical results from previous literature.This model is applied to analyze the effects of rock shape and impact angle on the dynamic interaction effects between falling rock and cushioned rock shed,including the impact force,transmitted bottom force,penetration depth,and plate deflection.The numerical results show that the variation in the falling rock’s shape has different effects on the falling rock with different impact angles.These findings could support rock shed design by revealing the limitations of the assumptions in the past research,which may result in unsafe rock sheds for some rockfall cases.
基金the National Natural Science Foundation of China(Grant No.51705287)the Scientific Research Foundation of Hubei Provincial Education Department(Grant No.D20211203).
文摘Finite element (FE) coupled thermal-mechanical analysis is widely used to predict the deformation and residualstress of wire arc additive manufacturing (WAAM) parts. In this study, an innovative single-layermulti-bead profilegeometric modeling method through the isosceles trapezoid function is proposed to build the FE model of theWAAMprocess. Firstly, a straight-line model for overlapping beads based on the parabola function was establishedto calculate the optimal center distance. Then, the isosceles trapezoid-based profile was employed to replace theparabola profiles of the parabola-based overlapping model to establish an innovative isosceles trapezoid-basedmulti-bead overlapping geometric model. The rationality of the isosceles trapezoid-based overlapping model wasconfirmed by comparing the geometric deviation and the heat dissipation performance index of the two overlappingmodels. In addition, the FE-coupled thermal-mechanical analysis, as well as a comparative experiment of thesingle-layer eight-bead deposition process show that the simulation results of the above two models agree with theexperimental results. At the same time, the proposed isosceles trapezoid-based overlappingmodels are all straightlineprofiles, which can be divided into high-quality FE elements. It can improve the modeling efficiency andshorten the simulation calculation time. The innovative modeling method proposed in this study can provide anefficient and high-precision geometricmodelingmethod forWAAMpart FE coupled thermal-mechanical analysis.
基金funded by the National Natural Science Foundation of China(Grant nos.42276255 and 41976227)project“Impact and Response of Antarctic Seas to Climate Change,IRASCC 2020-2022”(Grant nos.01-01-02A and 02-02-05).
文摘The Southern Ocean is an important carbon sink pool and plays a critical role in the global carbon cycling.The Amundsen Sea was reported to be highly productive in inshore area in the Southern Ocean.In order to investigate the influence of transparent exopolymer particles(TEP)on the behavior of dissolved organic carbon(DOC)in this region,a comprehensive study was conducted,encompassing both open water areas and highly productive polynyas.It was found that microbial heterotrophic metabolism is the primary process responsible for the production of humic-like fluorescent components in the open ocean.The relationship between apparent oxygen utilization and the two humic-like components can be accurately described by a power-law function,with a conversion rate consistent with that observed globally.The presence of TEP was found to have little impact on this process.Additionally,the study revealed the accumulation of DOC at the sea surface in the Amundsen Sea Polynya,suggesting that TEP may play a critical role in this phenomenon.These findings contribute to a deeper understanding of the dynamics and surface accumulation of DOC in the Amundsen Sea Polynya,and provide valuable insights into the carbon cycle in this region.