Based on data of trade, foreign directinvestment (FDI), economic development andenvironmental conditions in China’s 30 provincesbetween 1990-2002, this paper deals with the impacton Environmental Kuznets Curve (EKC) ...Based on data of trade, foreign directinvestment (FDI), economic development andenvironmental conditions in China’s 30 provincesbetween 1990-2002, this paper deals with the impacton Environmental Kuznets Curve (EKC) of tradeand FDI in China. The results show no direct impacton EKC of trade, on the one hand. However, tradecontributes significantly to economic growth, andhas played a positive role in introducing advancedpollution prevention technology and environmentalmanagement methodology to China. Therefore, aproactive trade policy will help solve the environmentalpollution problem brought by economic growth. Onthe other hand, there is a positive correlation betweenFDI and pollutant emission, which proves that FDIdoes have some negative influence on environmentin China due to hasty introduction of foreign capitaland inadequate environmental management systemin China.展开更多
[Objective] The aim was to analyze the characteristics of environmental Kuznets curve (EKC) and assess air quality in Qingdao City. [Method] The EKC characteristics of Qingdao from 1996 to 2008 were studied based on a...[Objective] The aim was to analyze the characteristics of environmental Kuznets curve (EKC) and assess air quality in Qingdao City. [Method] The EKC characteristics of Qingdao from 1996 to 2008 were studied based on air pollutant discharge indices, air pollution indices and economic data from the environmental quality reports and statistics yearbooks of Qingdao, and the air quality of Qingdao City was assessed. [Result] With the increase of GDP per capita, the total discharge of industrial waste gases improved remarkably, and its EKC showed inverted U type. Meanwhile, the discharge of SO2, industrial fumes and industrial dusts decreased on the whole, and the EKC of sulfur dioxide and industrial fumes was close to inverted N type. In addition, air pollution composite index also showed decrease trend, and its EKC showed inverted N type. In recent 13 years, the concentration of SO2, particles and NO2 in ambient air of Qingdao City showed decrease trend on the whole, especially particles. In addition, PM10 has replaced SO2 as the primary pollutant since 2001, and air pollution type has changed from coal smoke pollution to mixed mode pollution of coal smoke and motor vehicle. The mitigation of air pollution in Qingdao City could be attributed to the implementation of industrial waste gas management by the governments of Qingdao City. [Conclusion] The study could provide theoretical foundations for the establishment of environmental policies in Qingdao City.展开更多
Based on the Environmental Kuznets Curve theory,the authors choose provincial panel data of China in 1990 2007 and adopt panel unit root and co-integration testing method to study whether there is Environmental Kuznet...Based on the Environmental Kuznets Curve theory,the authors choose provincial panel data of China in 1990 2007 and adopt panel unit root and co-integration testing method to study whether there is Environmental Kuznets Curve for China's carbon emissions.The research results show that:carbon emissions per capita of the eastern region and the central region of China fit into Environmental Kuznets Curve,but that of the western region does not.On this basis,the authors carry out scenario analysis on the occurrence time of the inflection point of carbon emissions per capita of different regions,and describe a specific time path.展开更多
We apply a two pronged approach to analyze the presence of Environmental Kuznets Curve, EKC, in three types of emissions in the People’s Republic of China from 1994 to 2014: a structural breakpoint analysis and a mod...We apply a two pronged approach to analyze the presence of Environmental Kuznets Curve, EKC, in three types of emissions in the People’s Republic of China from 1994 to 2014: a structural breakpoint analysis and a model based test. We apply it to PM2.5, industrial waste and domestic water pollution time series, and find evidence of EKC in all three types of emissions that require appropriate policy.展开更多
The relationship between the emission of pollutant and economic growth has attracted a lot of attention in the environmental debate of the recent decades. Based on some theoretical and empirical research on environmen...The relationship between the emission of pollutant and economic growth has attracted a lot of attention in the environmental debate of the recent decades. Based on some theoretical and empirical research on environmental Kuznets curve (EKC), this paper introduces the environmental technical innovation and environmental investment into Solow growth model to discuss the relationship between GDP per capital and the emission of pollutant. By the dynamic simulation and parameters analysis, the results of the model indicate: (1) when "green" technical progress and environmental investment are fixed, the relationship between GDP per capital and the emission shows the linear relationship; (2) "green" technical progress can lead to the positive growth rates with a decreasing level of emis-sion, which is compatible with an EKC; (3) the proportion of the environmental investment can lead the different growth rates and level of emission. These results can explain that developing countries are "too poor to be green" .展开更多
Based on theoretical derivation,this paper aims to analyse the internal relationship between Porter Hypothesis and Environmental Kuznets Curve.Conclusions were made:(1)In terms of theoretical analysis and empirical re...Based on theoretical derivation,this paper aims to analyse the internal relationship between Porter Hypothesis and Environmental Kuznets Curve.Conclusions were made:(1)In terms of theoretical analysis and empirical researches,the existence of inverted U-shaped EKC and U-shaped Porter Curve has its rationality,most of the controversy come from the misuse and diversity of empirical methods;(2)The progress of Porter Hypothesis also relys on economic growth,which is compatible with EKC;(3)Similar to EKC,a threshold effect exist in the process of technological progress.Environmental regulation is a driving force to promote the widespread use of green technology and reach the threshold.(4)In the process of speeding up economic development,government should gradually increase the intensity of environmental regulation.展开更多
In this paper,we consider the effects of environmental perturbations such as the variations of temperature and climate on the growth of water hyacinth and fish species,as well as the economic and application values of...In this paper,we consider the effects of environmental perturbations such as the variations of temperature and climate on the growth of water hyacinth and fish species,as well as the economic and application values of these two species.We first present a triangular fuzzy water hyacinth-fish ecological model with Kuznets curve effect and linear harvesting.Then,we discuss the existence of the equilibria and their stability.It is then followed by analyzing the existence of bionomic equilibrium and determining the optimal harvesting policy via Pontryagin's Maximum Principle.Finally,numerical simulations are performed to validate the theoretical results.Our research indicates that fuzzy parameters may affect the optimal harvesting strategy.展开更多
In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily based on abrupt changes observed in the inclinometric curve.In conventional identification methods,inclinometric curv...In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily based on abrupt changes observed in the inclinometric curve.In conventional identification methods,inclinometric curves exhibiting indications of sliding can be categorized into three types:B-type,D-type,and r-type.The position of the slip surface is typically determined by identifying the depth corresponding to the point of maximum displacement mutation.However,this method is sensitive to the interval of measurement points and the observation scale of the coordinate axes and suffers from unclear sliding surfaces and uncertain values.Based on the variation characteristics of these diagonal curves,we classified the landslide into three components:the sliding body,the sliding interval,and the immobile body.Moreover,three different generalization models were established to analyze the relationships between the curve form and the slip surface location based on different physical indicators such as displacement rate,relative displacement,and acceleration.The results show that the displacement rate curves of an r-type slope exhibit a clustering feature in the sliding interval,and by solving for the depth of discrete points within the step phase,it is possible to determine the location of the slip surface.On the other hand,D-type slopes have inflection points in the relative displacement curve located at the slip surface.The acceleration curves of B-type slopes exhibit clustering characteristics during the sliding interval,while the scattered acceleration data demonstrate wandering characteristics.Consequently,the slip surface location can be revealed by solving the depth corresponding to the maximum acceleration with cubic spline interpolation.The approach proposed in this paper was applied to the monitoring data of a landslide in Yunnan Province,China.The results indicate that our approach can accurately identify the slip surface location and enable computability of its position,thereby enhancing applicability and reliability of the deep-hole displacement monitoring data.展开更多
Recently,a description on a practicability of the Wöhler Curve Method for low-cycle fatigue of metals was given by the author.By the description and the low cycle fatigue test data of 16 MnR steel,it is important...Recently,a description on a practicability of the Wöhler Curve Method for low-cycle fatigue of metals was given by the author.By the description and the low cycle fatigue test data of 16 MnR steel,it is important to show that,for low cycle fatigue of metals,such a way that a stress-based intensity parameter calculated by the linear-elastic analysis is taken to be a stress intensity parameter,S,to establish a relationship between the stress intensity parameter,S,and the fatigue life,N,is practicable.In this paper,many metallic materials from the literature are given to show that the Wöhler Curve Method is well suitable for low-cycle fatigue analysis of metals.展开更多
With its generality and practicality, the combination of partial charging curves and machine learning(ML) for battery capacity estimation has attracted widespread attention. However, a clear classification,fair compar...With its generality and practicality, the combination of partial charging curves and machine learning(ML) for battery capacity estimation has attracted widespread attention. However, a clear classification,fair comparison, and performance rationalization of these methods are lacking, due to the scattered existing studies. To address these issues, we develop 20 capacity estimation methods from three perspectives:charging sequence construction, input forms, and ML models. 22,582 charging curves are generated from 44 cells with different battery chemistry and operating conditions to validate the performance. Through comprehensive and unbiased comparison, the long short-term memory(LSTM) based neural network exhibits the best accuracy and robustness. Across all 6503 tested samples, the mean absolute percentage error(MAPE) for capacity estimation using LSTM is 0.61%, with a maximum error of only 3.94%. Even with the addition of 3 m V voltage noise or the extension of sampling intervals to 60 s, the average MAPE remains below 2%. Furthermore, the charging sequences are provided with physical explanations related to battery degradation to enhance confidence in their application. Recommendations for using other competitive methods are also presented. This work provides valuable insights and guidance for estimating battery capacity based on partial charging curves.展开更多
We derive an effective Hamiltonian for a spin-1/2 particle confined within a curved thin layer with non-uniform thickness using the confining potential approach.Our analysis reveals the presence of a pseudo-magnetic f...We derive an effective Hamiltonian for a spin-1/2 particle confined within a curved thin layer with non-uniform thickness using the confining potential approach.Our analysis reveals the presence of a pseudo-magnetic field and effective spin–orbit interaction(SOI)arising from the curvature,as well as an effective scalar potential resulting from variations in thickness.Importantly,we demonstrate that the physical effect of additional SOI from thickness fluctuations vanishes in low-dimensional systems,thus guaranteeing the robustness of spin interference measurements to thickness imperfection.Furthermore,we establish the applicability of the effective Hamiltonian in both symmetric and asymmetric confinement scenarios,which is crucial for its utilization in one-side etching systems.展开更多
AASHTO’s guideline for geometric design of highways and similar guidelines require that roadside areas on the inside of horizontal curves be cleared of high objects to provide stopping sight distance. The guidelines ...AASHTO’s guideline for geometric design of highways and similar guidelines require that roadside areas on the inside of horizontal curves be cleared of high objects to provide stopping sight distance. The guidelines have analytical models for determining the extent of clearance, known as the horizontal sightline offset or clearance offset, for simple curves. Researchers in the past have developed analytical models for clearance offsets for spiraled and reverse curves. Very few researchers developed analytical models for available sight distances for compound curves. Still missing are models for horizontal sightline offsets and locations of the offsets for compound curves. The objective of this paper is to present development of analytical models and charts for determining horizontal sightline offsets and their locations for compound curves. The paper considers curves whose component arcs are individually shorter than stopping sight distance. The resulting models and the charts have been verified with accurate values determined using graphical methods. The models and the charts will find application in geometric design of highway compound curves.展开更多
Due to the novel applications of flexible pipes conveying fluid in the field of soft robotics and biomedicine,the investigations on the mechanical responses of the pipes have attracted considerable attention.The fluid...Due to the novel applications of flexible pipes conveying fluid in the field of soft robotics and biomedicine,the investigations on the mechanical responses of the pipes have attracted considerable attention.The fluid-structure interaction(FSI)between the pipe with a curved shape and the time-varying internal fluid flow brings a great challenge to the revelation of the dynamical behaviors of flexible pipes,especially when the pipe is highly flexible and usually undergoes large deformations.In this work,the geometrically exact model(GEM)for a curved cantilevered pipe conveying pulsating fluid is developed based on the extended Hamilton's principle.The stability of the curved pipe with three different subtended angles is examined with the consideration of steady fluid flow.Specific attention is concentrated on the large-deformation resonance of circular pipes conveying pulsating fluid,which is often encountered in practical engineering.By constructing bifurcation diagrams,oscillating shapes,phase portraits,time traces,and Poincarémaps,the dynamic responses of the curved pipe under various system parameters are revealed.The mean flow velocity of the pulsating fluid is chosen to be either subcritical or supercritical.The numerical results show that the curved pipe conveying pulsating fluid can exhibit rich dynamical behaviors,including periodic and quasi-periodic motions.It is also found that the preferred instability type of a cantilevered curved pipe conveying steady fluid is mainly in the flutter of the second mode.For a moderate value of the mass ratio,however,a third-mode flutter may occur,which is quite different from that of a straight pipe system.展开更多
Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during ...Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW.展开更多
The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigate...The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigated.The current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial velocity.For the layer analysis,the high-order shear deformation theory(HSDT)and Frostig's second model for the displacement fields of the core layer are used.The classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of time.In order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the LVI.Finite element(FE)simulations are conducted by means of the ABAQUS software.The effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.展开更多
This article explores the fundamentals of small-radius curved ramp bridges.It covers the selection of box girder spans,support methods,and forms,along with design optimization techniques for this type of bridge struct...This article explores the fundamentals of small-radius curved ramp bridges.It covers the selection of box girder spans,support methods,and forms,along with design optimization techniques for this type of bridge structure.The purpose of this paper is to provide robust support for enhancing the design quality of these bridges and ensuring their efficacy in real-world applications.展开更多
文摘Based on data of trade, foreign directinvestment (FDI), economic development andenvironmental conditions in China’s 30 provincesbetween 1990-2002, this paper deals with the impacton Environmental Kuznets Curve (EKC) of tradeand FDI in China. The results show no direct impacton EKC of trade, on the one hand. However, tradecontributes significantly to economic growth, andhas played a positive role in introducing advancedpollution prevention technology and environmentalmanagement methodology to China. Therefore, aproactive trade policy will help solve the environmentalpollution problem brought by economic growth. Onthe other hand, there is a positive correlation betweenFDI and pollutant emission, which proves that FDIdoes have some negative influence on environmentin China due to hasty introduction of foreign capitaland inadequate environmental management systemin China.
基金Supported by Soft Scientific Project(2009RKA185)Project of Educational Commission of Shandong Province(J08WB04)
文摘[Objective] The aim was to analyze the characteristics of environmental Kuznets curve (EKC) and assess air quality in Qingdao City. [Method] The EKC characteristics of Qingdao from 1996 to 2008 were studied based on air pollutant discharge indices, air pollution indices and economic data from the environmental quality reports and statistics yearbooks of Qingdao, and the air quality of Qingdao City was assessed. [Result] With the increase of GDP per capita, the total discharge of industrial waste gases improved remarkably, and its EKC showed inverted U type. Meanwhile, the discharge of SO2, industrial fumes and industrial dusts decreased on the whole, and the EKC of sulfur dioxide and industrial fumes was close to inverted N type. In addition, air pollution composite index also showed decrease trend, and its EKC showed inverted N type. In recent 13 years, the concentration of SO2, particles and NO2 in ambient air of Qingdao City showed decrease trend on the whole, especially particles. In addition, PM10 has replaced SO2 as the primary pollutant since 2001, and air pollution type has changed from coal smoke pollution to mixed mode pollution of coal smoke and motor vehicle. The mitigation of air pollution in Qingdao City could be attributed to the implementation of industrial waste gas management by the governments of Qingdao City. [Conclusion] The study could provide theoretical foundations for the establishment of environmental policies in Qingdao City.
文摘Based on the Environmental Kuznets Curve theory,the authors choose provincial panel data of China in 1990 2007 and adopt panel unit root and co-integration testing method to study whether there is Environmental Kuznets Curve for China's carbon emissions.The research results show that:carbon emissions per capita of the eastern region and the central region of China fit into Environmental Kuznets Curve,but that of the western region does not.On this basis,the authors carry out scenario analysis on the occurrence time of the inflection point of carbon emissions per capita of different regions,and describe a specific time path.
文摘We apply a two pronged approach to analyze the presence of Environmental Kuznets Curve, EKC, in three types of emissions in the People’s Republic of China from 1994 to 2014: a structural breakpoint analysis and a model based test. We apply it to PM2.5, industrial waste and domestic water pollution time series, and find evidence of EKC in all three types of emissions that require appropriate policy.
文摘The relationship between the emission of pollutant and economic growth has attracted a lot of attention in the environmental debate of the recent decades. Based on some theoretical and empirical research on environmental Kuznets curve (EKC), this paper introduces the environmental technical innovation and environmental investment into Solow growth model to discuss the relationship between GDP per capital and the emission of pollutant. By the dynamic simulation and parameters analysis, the results of the model indicate: (1) when "green" technical progress and environmental investment are fixed, the relationship between GDP per capital and the emission shows the linear relationship; (2) "green" technical progress can lead to the positive growth rates with a decreasing level of emis-sion, which is compatible with an EKC; (3) the proportion of the environmental investment can lead the different growth rates and level of emission. These results can explain that developing countries are "too poor to be green" .
文摘Based on theoretical derivation,this paper aims to analyse the internal relationship between Porter Hypothesis and Environmental Kuznets Curve.Conclusions were made:(1)In terms of theoretical analysis and empirical researches,the existence of inverted U-shaped EKC and U-shaped Porter Curve has its rationality,most of the controversy come from the misuse and diversity of empirical methods;(2)The progress of Porter Hypothesis also relys on economic growth,which is compatible with EKC;(3)Similar to EKC,a threshold effect exist in the process of technological progress.Environmental regulation is a driving force to promote the widespread use of green technology and reach the threshold.(4)In the process of speeding up economic development,government should gradually increase the intensity of environmental regulation.
文摘In this paper,we consider the effects of environmental perturbations such as the variations of temperature and climate on the growth of water hyacinth and fish species,as well as the economic and application values of these two species.We first present a triangular fuzzy water hyacinth-fish ecological model with Kuznets curve effect and linear harvesting.Then,we discuss the existence of the equilibria and their stability.It is then followed by analyzing the existence of bionomic equilibrium and determining the optimal harvesting policy via Pontryagin's Maximum Principle.Finally,numerical simulations are performed to validate the theoretical results.Our research indicates that fuzzy parameters may affect the optimal harvesting strategy.
基金supported by the Scientific and Technological Research and Development Programs of China Railway Group Limited(Grant No.2022 Major Special Project-07)Gansu Provincial Technology Innovation Guidance Program-Special Funding for Capacity Building of Enterprise R&D Institutions(Grant No.23CXJA0011)Key R&D and transformation plan of Qinghai Province,China(Special Project for Transformation of Scientific and Technological Achievements No.2022-SF-158).
文摘In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily based on abrupt changes observed in the inclinometric curve.In conventional identification methods,inclinometric curves exhibiting indications of sliding can be categorized into three types:B-type,D-type,and r-type.The position of the slip surface is typically determined by identifying the depth corresponding to the point of maximum displacement mutation.However,this method is sensitive to the interval of measurement points and the observation scale of the coordinate axes and suffers from unclear sliding surfaces and uncertain values.Based on the variation characteristics of these diagonal curves,we classified the landslide into three components:the sliding body,the sliding interval,and the immobile body.Moreover,three different generalization models were established to analyze the relationships between the curve form and the slip surface location based on different physical indicators such as displacement rate,relative displacement,and acceleration.The results show that the displacement rate curves of an r-type slope exhibit a clustering feature in the sliding interval,and by solving for the depth of discrete points within the step phase,it is possible to determine the location of the slip surface.On the other hand,D-type slopes have inflection points in the relative displacement curve located at the slip surface.The acceleration curves of B-type slopes exhibit clustering characteristics during the sliding interval,while the scattered acceleration data demonstrate wandering characteristics.Consequently,the slip surface location can be revealed by solving the depth corresponding to the maximum acceleration with cubic spline interpolation.The approach proposed in this paper was applied to the monitoring data of a landslide in Yunnan Province,China.The results indicate that our approach can accurately identify the slip surface location and enable computability of its position,thereby enhancing applicability and reliability of the deep-hole displacement monitoring data.
文摘Recently,a description on a practicability of the Wöhler Curve Method for low-cycle fatigue of metals was given by the author.By the description and the low cycle fatigue test data of 16 MnR steel,it is important to show that,for low cycle fatigue of metals,such a way that a stress-based intensity parameter calculated by the linear-elastic analysis is taken to be a stress intensity parameter,S,to establish a relationship between the stress intensity parameter,S,and the fatigue life,N,is practicable.In this paper,many metallic materials from the literature are given to show that the Wöhler Curve Method is well suitable for low-cycle fatigue analysis of metals.
基金supported by the National Natural Science Foundation of China (52075420)the National Key Research and Development Program of China (2020YFB1708400)。
文摘With its generality and practicality, the combination of partial charging curves and machine learning(ML) for battery capacity estimation has attracted widespread attention. However, a clear classification,fair comparison, and performance rationalization of these methods are lacking, due to the scattered existing studies. To address these issues, we develop 20 capacity estimation methods from three perspectives:charging sequence construction, input forms, and ML models. 22,582 charging curves are generated from 44 cells with different battery chemistry and operating conditions to validate the performance. Through comprehensive and unbiased comparison, the long short-term memory(LSTM) based neural network exhibits the best accuracy and robustness. Across all 6503 tested samples, the mean absolute percentage error(MAPE) for capacity estimation using LSTM is 0.61%, with a maximum error of only 3.94%. Even with the addition of 3 m V voltage noise or the extension of sampling intervals to 60 s, the average MAPE remains below 2%. Furthermore, the charging sequences are provided with physical explanations related to battery degradation to enhance confidence in their application. Recommendations for using other competitive methods are also presented. This work provides valuable insights and guidance for estimating battery capacity based on partial charging curves.
基金This work was supported in part by the National Natural Science Foundation of China(Grant No.12104239)National Natural Science Foundation of Jiangsu Province of China(Grant No.BK20210581)+2 种基金Nanjing University of Posts and Telecommunications Science Foundation(Grant Nos.NY221024 and NY221100)the Science and Technology Program of Guangxi,China(Grant No.2018AD19310)the Jiangxi Provincial Natural Science Foundation(Grant No.20224BAB211020).
文摘We derive an effective Hamiltonian for a spin-1/2 particle confined within a curved thin layer with non-uniform thickness using the confining potential approach.Our analysis reveals the presence of a pseudo-magnetic field and effective spin–orbit interaction(SOI)arising from the curvature,as well as an effective scalar potential resulting from variations in thickness.Importantly,we demonstrate that the physical effect of additional SOI from thickness fluctuations vanishes in low-dimensional systems,thus guaranteeing the robustness of spin interference measurements to thickness imperfection.Furthermore,we establish the applicability of the effective Hamiltonian in both symmetric and asymmetric confinement scenarios,which is crucial for its utilization in one-side etching systems.
文摘AASHTO’s guideline for geometric design of highways and similar guidelines require that roadside areas on the inside of horizontal curves be cleared of high objects to provide stopping sight distance. The guidelines have analytical models for determining the extent of clearance, known as the horizontal sightline offset or clearance offset, for simple curves. Researchers in the past have developed analytical models for clearance offsets for spiraled and reverse curves. Very few researchers developed analytical models for available sight distances for compound curves. Still missing are models for horizontal sightline offsets and locations of the offsets for compound curves. The objective of this paper is to present development of analytical models and charts for determining horizontal sightline offsets and their locations for compound curves. The paper considers curves whose component arcs are individually shorter than stopping sight distance. The resulting models and the charts have been verified with accurate values determined using graphical methods. The models and the charts will find application in geometric design of highway compound curves.
基金Project supported by the National Natural Science Foundation of China (Nos.12072119,12325201,and 52205594)the China National Postdoctoral Program for Innovative Talents (No.BX20220118)。
文摘Due to the novel applications of flexible pipes conveying fluid in the field of soft robotics and biomedicine,the investigations on the mechanical responses of the pipes have attracted considerable attention.The fluid-structure interaction(FSI)between the pipe with a curved shape and the time-varying internal fluid flow brings a great challenge to the revelation of the dynamical behaviors of flexible pipes,especially when the pipe is highly flexible and usually undergoes large deformations.In this work,the geometrically exact model(GEM)for a curved cantilevered pipe conveying pulsating fluid is developed based on the extended Hamilton's principle.The stability of the curved pipe with three different subtended angles is examined with the consideration of steady fluid flow.Specific attention is concentrated on the large-deformation resonance of circular pipes conveying pulsating fluid,which is often encountered in practical engineering.By constructing bifurcation diagrams,oscillating shapes,phase portraits,time traces,and Poincarémaps,the dynamic responses of the curved pipe under various system parameters are revealed.The mean flow velocity of the pulsating fluid is chosen to be either subcritical or supercritical.The numerical results show that the curved pipe conveying pulsating fluid can exhibit rich dynamical behaviors,including periodic and quasi-periodic motions.It is also found that the preferred instability type of a cantilevered curved pipe conveying steady fluid is mainly in the flutter of the second mode.For a moderate value of the mass ratio,however,a third-mode flutter may occur,which is quite different from that of a straight pipe system.
基金National Key Research and Development Program of China under Grant No.2018YFC0705602。
文摘Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW.
文摘The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigated.The current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial velocity.For the layer analysis,the high-order shear deformation theory(HSDT)and Frostig's second model for the displacement fields of the core layer are used.The classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of time.In order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the LVI.Finite element(FE)simulations are conducted by means of the ABAQUS software.The effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.
文摘This article explores the fundamentals of small-radius curved ramp bridges.It covers the selection of box girder spans,support methods,and forms,along with design optimization techniques for this type of bridge structure.The purpose of this paper is to provide robust support for enhancing the design quality of these bridges and ensuring their efficacy in real-world applications.
基金This study was supported by the State Basic Science Key Project of China （No. 2007FY110300）, the National Natural Science Foundation of China （Grant Nos. 41271556 and 41301642）, China Postdoctoral Science Foundation Funded Project （No. 2013M541026）, and the Go｜da Meir Fellowship. This paper was finally finished while the first author was a Fellow at the Department of Geography, The Hebrew University of Jerusalem. The authors would like to appreciate Professor Eran Feitelson and Ms Rachel Friedman for their guidance and comments.
文摘作为到水缺陷的最大的贡献者，农业相关的污染吸引了科学家以及政策制造者的注意，并且量的信息正在被寻求集中并且进展政策争论。这研究使用面板单位根，异构的面板 cointegration，和在从 1989 ～ 2009 为 31 省的经济从农业合成化肥，杀虫剂，和电影的使用导致大陆中国的环境问题上调查环境 Kuznets 曲线的基于面板的动态平常的最少的广场。实验结果显示积极长期间在环境索引和真实 GDP 之间的 co 综合的关系人均。这种关系呈现转弯的点的转换 U 字形的环境 Kuznets 曲线，和价值分别地是约 10,00013,000， 85,00089,000 和超过 160,000 CNY，为合成化肥氮指示物，化肥磷指示物和杀虫剂指示物。目前，中国服从于巨大的环境压力并且应该把更多的重要性分到特殊农业相关的环境问题。
