Marine science technology innovation provides power and guarantees for marine eco-civilization construction,which provides direction and material support for marine science technology innovation.Therefore,the coordina...Marine science technology innovation provides power and guarantees for marine eco-civilization construction,which provides direction and material support for marine science technology innovation.Therefore,the coordinated development of the two is of great significance to the marine economy sustainable development in China’s coastal areas.On the basis of clarifying the connotations of marine science technology innovation and marine eco-civilization in China’s coastal areas from 2006 to 2019,the mechanism for their coordinated development was analysed.A comprehensive indicator system based on the connotation of the two was constructed,and the coordinated development relationship was empirically tested using the coupled coordination model and the panel vector autoregressive(PVAR)model.The results show that:1)the level of China’s coastal marine science technology innovation continues to improve,gradually forming the core of the development of marine science technology innovation in the north,east and south of Shandong,Shanghai and Guangdong;the level of marine eco-civilization development fluctuating upward trend,showing obvious spatial differentiation characteristics.2)The degree of coordination of marine science technology innovation and marine eco-civilization is growing over time.There is no causal relationship between marine science technology innovation and marine eco-civilization in the northern marine economic circle,but there is a two-way causal relationship between the two in the eastern and southern marine economic circles.3)Marine eco-civilization shows a significant positive and continuous impact on marine science technology innovation,and marine science technology innovation shows a long-term,continuous,fluctuating,and lagging impact on marine eco-civilization.The overall role of marine eco-civilization on marine science technology innovation is dominant,and there are significant differences in the impact effects of the two major marine economic circles.展开更多
To solve the problem of long response time when users obtain suitable cutting parameters through the Internet based platform,a case-based reasoning framework is proposed.Specifically,a Hamming distance and Euclidean d...To solve the problem of long response time when users obtain suitable cutting parameters through the Internet based platform,a case-based reasoning framework is proposed.Specifically,a Hamming distance and Euclidean distance combined method is designed to measure the similarity of case features which have both numeric and category properties.In addition,AHP(Analytic Hierarchy Process)and entropy weight method are integrated to provide features weight,where both user preferences and comprehensive impact of the index have been concerned.Grey relation analysis is used to obtain the similarity of a new problem and alternative cases.Finally,a platform is also developed on Visual Studio 2015,and a case study is demonstrated to verify the practicality and efficiency of the proposed method.This method can obtain cutting parameters which is suitable without iterative calculation.Compared with the traditional PSO(Particle swarm optimization algorithm)and GA(Genetic algorithm),it can obtain faster response speed.This method can provide ideas for selecting processing parameters in industrial production.While guaranteeing the characteristic information is similar,this approach can select processing parameters which is the most appropriate for the production process and a lot of time can be saved.展开更多
Amidst the swift advancement of new power systems and electric vehicles,inverter-fed machines have progressively materialized as a pivotal apparatus for efficient energy conversion.Stator winding turn insulation failu...Amidst the swift advancement of new power systems and electric vehicles,inverter-fed machines have progressively materialized as a pivotal apparatus for efficient energy conversion.Stator winding turn insulation failure is the root cause of inverter-fed machine breakdown.The online monitoring of turn insulation health can detect potential safety risks promptly,but faces the challenge of weak characteristics of turn insulation degradation.This study proposes an innovative method to evaluate the turn insulation state of inverter-fed machines by utilizing the fractional Fourier transform with a Mel filter(FrFT-Mel).First,the sensitivity of the high-frequency(HF)switching oscillation current to variations in turn insulation was analyzed within the fractional domain.Subsequently,an improved Mel filter is introduced,and its structure and parameters are specifically designed based on the features intrinsic to the common-mode impedance resonance point of the electrical machine.Finally,an evaluation index was proposed for the turn insulation state of inverter-fed machines.Experimental results on a 3kW permanent magnet synchronous machine(PMSM)demonstrate that the proposed FrFT-Mel method significantly enhances the sensitivity of turn insulation state perception by approximately five times,compared to the traditional Fourier transform method.展开更多
Experimental investigations on dynamic in-plane compressive behavior of a plain weave composite were performed using the split Hopkinson pressure bar. A quantitative criterion for calculating the constant strain rate ...Experimental investigations on dynamic in-plane compressive behavior of a plain weave composite were performed using the split Hopkinson pressure bar. A quantitative criterion for calculating the constant strain rate of composites was established. Then the upper limit of strain rate, restricted by stress equilibrium and constant loading rate, was rationally estimated and confirmed by tests. Within the achievable range of 0.001/s-895/s, it was found that the strength increased first and subsequently decreased as the strain rate increased. This feature was also reflected by the turning point(579/s) of the bilinear model for strength prediction. The transition in failure mechanism, from local opening damage to completely splitting destruction, was mainly responsible for such strain rate effects. And three major failure modes were summarized under microscopic observations: fiber fracture, inter-fiber fracture, and interface delamination. Finally, by introducing a nonlinear damage variable, a simplified ZWT model was developed to characterize the dynamic mechanical response. Excellent agreement was shown between the experimental and simulated results.展开更多
Since the 1990s the so-called spatial turn has brought back space and topography into the discussion within historical studies,particular ancient studies.This survey reviews current trends and developments within the ...Since the 1990s the so-called spatial turn has brought back space and topography into the discussion within historical studies,particular ancient studies.This survey reviews current trends and developments within the field and offers some perspectives on possible future developments related to space,material,objects,their agency,and frames.展开更多
The concept of eco-civilization in China now is a hot issue.It has drawn sufficient attention from all walks of life,both in industry and academia.Not only Chinese domestic researcher focus on this area,but also many ...The concept of eco-civilization in China now is a hot issue.It has drawn sufficient attention from all walks of life,both in industry and academia.Not only Chinese domestic researcher focus on this area,but also many Western contributors shed light on this concept.For example,Arran E.Gare(1995),whose work aims to search for the roots of the global ecological crisis,and the cultural conditions to overcome it,and he reveals that environmental awareness has undoubtedly grown over the last two decades.The purpose of this research is to explore the core tenets and criteria of Community-based Ecotourism(CBET),environmental/eco-awareness and examine its contribution to Chinese eco-civilization,to voice Chinese's contribution to the Western world as ecological civilization represents the most advanced and sustainable mode of civilization in human history,and how to use ecological civilization philosophy to guide the develop of CBET in China,and in return,how to integrate concepts of CBET,environmental/eco-awareness with the process of Chinese eco-civilization nowadays.展开更多
The construction of eco-civilization is an important part of socialist construction in China, and its achievements are related to the cultivation and effective implementation of the concept of sustainable development....The construction of eco-civilization is an important part of socialist construction in China, and its achievements are related to the cultivation and effective implementation of the concept of sustainable development. In his report to the Nineteenth National Congress, President Xi Jin-ping pointed out that the construction of eco-civilization is an important content that affects our country and the global ecological environment. Clear ideas and measures to solve the people's needs for a better life and development imbalance between the contradictions. This paper expounds the relationship between ideological and political education and eco-civilization, and analyzes the role of modern ideological and political education in the construction of eco-civilization. The purpose of this paper is to clarify the modern ideological and political education and the construction of eco-civilization. The mutual relations lay the foundation for giving play to the role of modern ideological and political education in the construction of eco-civilization.展开更多
We try to inject the idea of marine eco-civilization into marine management. By enriching connotation of marine management,the idea of marine management is improved by combining ecology,sociology and management. Curre...We try to inject the idea of marine eco-civilization into marine management. By enriching connotation of marine management,the idea of marine management is improved by combining ecology,sociology and management. Current marine management in China has many problems. From the angle of enhancing marine eco-civilization construction,we put forward that marine area in whole country needs to be planned by taking marine eco-civilization as starting point,regional marine management idea should be enhanced,and division of marine management unit should be innovated,finally realizing innovation of marine management mechanism and marine sustainable development.展开更多
This article proposes an integral-based event-triggered attack-resilient control method for the aircraft-on-ground(AoG) synergistic turning system with uncertain tire cornering stiffness under stochastic deception att...This article proposes an integral-based event-triggered attack-resilient control method for the aircraft-on-ground(AoG) synergistic turning system with uncertain tire cornering stiffness under stochastic deception attacks. First, a novel AoG synergistic turning model is established with synergistic reverse steering of the front and main wheels to decrease the steering angle of the AoG fuselage, thus reducing the steady-state error when it follows a path with some large curvature. Considering that the tire cornering stiffness of the front and main wheels vary during steering, a dynamical observer is designed to adaptively identify them and estimate the system state at the same time.Then, an integral-based event-triggered mechanism(I-ETM) is synthesized to reduce the transmission frequency at the observerto-controller end, where stochastic deception attacks may occur at any time with a stochastic probability. Moreover, an attackresilient controller is designed to guarantee that the closed-loop system is robust L2-stable under stochastic attacks and external disturbances. A co-design method is provided to get feasible solutions for the observer, controller, and I-ETM simultaneously. An optimization program is further presented to make a tradeoff between the robustness of the control scheme and the saving of communication resources. Finally, the low-and high-probability stochastic deception attacks are considered in the simulations. The results have illustrated that the AoG synergistic turning system with the proposed control method follows a path with some large curvature well under stochastic deception attacks. Furthermore,compared with the static event-triggered mechanisms, the proposed I-ETM has demonstrated its superiority in saving communication resources.展开更多
This paper explores four issues concerning aesthetics. First is the groundless concept of eco-aesthetics. In nature, aesthetics is the outcome of civilization and aesthetic appreciation is a process of human's sel...This paper explores four issues concerning aesthetics. First is the groundless concept of eco-aesthetics. In nature, aesthetics is the outcome of civilization and aesthetic appreciation is a process of human's self-affirmation. Fundamentally, ecology is the opposite of civilization. Ecology is beautiful only when it benefits humans and civilizations. The concept of ecological beauty is groundless and what exists can only be the beauty of eco-civilization. Second is the symbiosis of ecology and civilization, which is the very essence of eco-civilization beauty. Third is simplicity, which is the defining beauty of eco-civilization aesthetics and originates from agricultural civilizations. Such an aesthetic view was negated by industrial civilizations and later realized self-renewal through "negation of negation. " Today, simplicity has become the defining beauty in the era of eco-civilizations. Frugality is the core of simplicity and it carries different connotations in different eras. In the era of agricultural civilizations, frugality was for wealth accumulation, while in the era of eco-civilizations frugality is for resource conservation. Fourth is the construction of eco-civilization aesthetics of which there are three noteworthy aspects; re-establishing the divinity of nature & advocating nature worship, re-humanizing and re-building trust in technology, and improving the quality of the "habitat for humanity. " The community of eco-civilization is the biggest ever shared homeland featuring harmonious co-existence between humans and nature. The aesthetics of eco-civilization are the aesthetics of the human homeland. "Happy living and dwelling" is an eternal theme of human aesthetics. When it comes to the era of eco-civilizations, however, this theme should be added with a prefix, i.e. "eco-" to form a new concept ─ "happy eco-living and dwelling."展开更多
This paper is devoted to the analysis and comparison of eco-civilization construction modes in China and major developed western countries, which mainly focuses on the typical advanced related ecocivilization construc...This paper is devoted to the analysis and comparison of eco-civilization construction modes in China and major developed western countries, which mainly focuses on the typical advanced related ecocivilization construction modes in different countries, cities or counties. Finally, it makes a comparative analysis at home and abroad, draws the conclusion and puts forward some main countermeasures and suggestions for China's eco-civilization construction on the basis of the existing research.展开更多
The report of the Nineteenth National Congress of the Communist Party of China clearly points out that we should speed up the reform of the ecological civilization system and build a beautiful China.Guizhou Province i...The report of the Nineteenth National Congress of the Communist Party of China clearly points out that we should speed up the reform of the ecological civilization system and build a beautiful China.Guizhou Province is one of the first demonstration zones of ecological civilization established by the State Council and themacro-ecological strategy is one of the three strategic actions of Guizhou Province.展开更多
From July 13 to 14,the“2019 China Eco-Civilization Construction Forum”,jointly sponsored by Chinese Ecological Economics Association and the journal of Ecological Economy and hosted by School of Economics,Guizhou Un...From July 13 to 14,the“2019 China Eco-Civilization Construction Forum”,jointly sponsored by Chinese Ecological Economics Association and the journal of Ecological Economy and hosted by School of Economics,Guizhou University was held in Guiyang City,Guizhou Province.The theme of the conference is Ecological Economy and Rural Revitalization.About 150 experts and scholars from more than 100 universities and research institutions attended the forum.Experts and scholars attending the meeting conducted in-depth discussions and exchanges on the system and mechanism of eco-civilization construction in the new era,ecocivilization and social responsibility,ecological economics theory and green development,rural revitalization and ecological poverty alleviation,ecological environment and ecological industry,ecological protection and ecological compensation.展开更多
The interaction between light and temperature is known to influence the seasonal growth of trees.Traditional studies on"light"primarily focus on day length,specifically short day(SD)or long day(LD)conditions...The interaction between light and temperature is known to influence the seasonal growth of trees.Traditional studies on"light"primarily focus on day length,specifically short day(SD)or long day(LD)conditions.However,little research has been conducted on the process of transitioning between SD and LD conditions.展开更多
The multi-pass turning operation is one of the most commonly used machining methods in manufacturing field.The main objective of this operation is to minimize the unit production cost.This paper proposes a Gaussian qu...The multi-pass turning operation is one of the most commonly used machining methods in manufacturing field.The main objective of this operation is to minimize the unit production cost.This paper proposes a Gaussian quantum-behaved bat algorithm(GQBA)to solve the problem of multi-pass turning operation.The proposed algorithm mainly includes the following two improvements.The first improvement is to incorporate the current optimal positions of quantum bats and the global best position into the stochastic attractor to facilitate population diversification.The second improvement is to use a Gaussian distribution instead of the uniform distribution to update the positions of the quantum-behaved bats,thus performing a more accurate search and avoiding premature convergence.The performance of the presented GQBA is demonstrated through numerical benchmark functions and amulti-pass turning operation problem.Thirteen classical benchmark functions are utilized in the comparison experiments,and the experimental results for accuracy and convergence speed demonstrate that,in most cases,the GQBA can provide a better search capability than other algorithms.Furthermore,GQBA is applied to an optimization problem formulti-pass turning,which is designed tominimize the production cost while considering many practical machining constraints in the machining process.The experimental results indicate that the GQBA outperforms other comparison algorithms in terms of cost reduction,which proves the effectiveness of the GQBA.展开更多
With the increasing use of difficult-to-machine materials in aerospace applications,machining requirements are becoming ever more rigorous.However,traditional single-point diamond turning(SPDT)can cause surface damage...With the increasing use of difficult-to-machine materials in aerospace applications,machining requirements are becoming ever more rigorous.However,traditional single-point diamond turning(SPDT)can cause surface damage and tool wear.Thus,it is difficult for SPDT to meet the processing requirements,and it has significant limitations.Research indicates that supplementing SPDT with unconventional techniques can,importantly,solve problems due to the high cutting forces and poor surface quality for difficult-to-machine materials.This paper first introduces SPDT and reviews research into unconventional techniques for use with SPDT.The machining mechanism is discussed,and the main advantages and disadvantages of various methods are investigated.Second,hybrid SPDT is briefly described,which encompasses ultrasonic-vibration magnetic-field SPDT,ultrasonic-vibration laser SPDT,and ultrasonic-vibration cold-plasma SPDT.Compared with the traditional SPDT method,hybrid SPDT produces a better optical surface quality.The current status of research into unconventional techniques to supplement SPDT is then summarized.Finally,future development trends and the application prospects of unconventional assisted SPDT are discussed.展开更多
Polycrystalline materials are extensively employed in industry.Its surface roughness significantly affects the working performance.Material defects,particularly grain boundaries,have a great impact on the achieved sur...Polycrystalline materials are extensively employed in industry.Its surface roughness significantly affects the working performance.Material defects,particularly grain boundaries,have a great impact on the achieved surface roughness of polycrystalline materials.However,it is difficult to establish a purely theoretical model for surface roughness with consideration of the grain boundary effect using conventional analytical methods.In this work,a theoretical and deep learning hybrid model for predicting the surface roughness of diamond-turned polycrystalline materials is proposed.The kinematic–dynamic roughness component in relation to the tool profile duplication effect,work material plastic side flow,relative vibration between the diamond tool and workpiece,etc,is theoretically calculated.The material-defect roughness component is modeled with a cascade forward neural network.In the neural network,the ratio of maximum undeformed chip thickness to cutting edge radius RT S,work material properties(misorientation angle θ_(g) and grain size d_(g)),and spindle rotation speed n s are configured as input variables.The material-defect roughness component is set as the output variable.To validate the developed model,polycrystalline copper with a gradient distribution of grains prepared by friction stir processing is machined with various processing parameters and different diamond tools.Compared with the previously developed model,obvious improvement in the prediction accuracy is observed with this hybrid prediction model.Based on this model,the influences of different factors on the surface roughness of polycrystalline materials are discussed.The influencing mechanism of the misorientation angle and grain size is quantitatively analyzed.Two fracture modes,including transcrystalline and intercrystalline fractures at different RTS values,are observed.Meanwhile,optimal processing parameters are obtained with a simulated annealing algorithm.Cutting experiments are performed with the optimal parameters,and a flat surface finish with Sa 1.314 nm is finally achieved.The developed model and corresponding new findings in this work are beneficial for accurately predicting the surface roughness of polycrystalline materials and understanding the impacting mechanism of material defects in diamond turning.展开更多
基金Under the auspices of the National Natural Science Foundation of China(No.42076222)。
文摘Marine science technology innovation provides power and guarantees for marine eco-civilization construction,which provides direction and material support for marine science technology innovation.Therefore,the coordinated development of the two is of great significance to the marine economy sustainable development in China’s coastal areas.On the basis of clarifying the connotations of marine science technology innovation and marine eco-civilization in China’s coastal areas from 2006 to 2019,the mechanism for their coordinated development was analysed.A comprehensive indicator system based on the connotation of the two was constructed,and the coordinated development relationship was empirically tested using the coupled coordination model and the panel vector autoregressive(PVAR)model.The results show that:1)the level of China’s coastal marine science technology innovation continues to improve,gradually forming the core of the development of marine science technology innovation in the north,east and south of Shandong,Shanghai and Guangdong;the level of marine eco-civilization development fluctuating upward trend,showing obvious spatial differentiation characteristics.2)The degree of coordination of marine science technology innovation and marine eco-civilization is growing over time.There is no causal relationship between marine science technology innovation and marine eco-civilization in the northern marine economic circle,but there is a two-way causal relationship between the two in the eastern and southern marine economic circles.3)Marine eco-civilization shows a significant positive and continuous impact on marine science technology innovation,and marine science technology innovation shows a long-term,continuous,fluctuating,and lagging impact on marine eco-civilization.The overall role of marine eco-civilization on marine science technology innovation is dominant,and there are significant differences in the impact effects of the two major marine economic circles.
基金the Sichuan Science and Technology Program(Nos.23ZHCG0049,2023YFG0078,23ZHCG0030,2021ZDZX0007)SCU-SUINING Project(2022CDSN-14).
文摘To solve the problem of long response time when users obtain suitable cutting parameters through the Internet based platform,a case-based reasoning framework is proposed.Specifically,a Hamming distance and Euclidean distance combined method is designed to measure the similarity of case features which have both numeric and category properties.In addition,AHP(Analytic Hierarchy Process)and entropy weight method are integrated to provide features weight,where both user preferences and comprehensive impact of the index have been concerned.Grey relation analysis is used to obtain the similarity of a new problem and alternative cases.Finally,a platform is also developed on Visual Studio 2015,and a case study is demonstrated to verify the practicality and efficiency of the proposed method.This method can obtain cutting parameters which is suitable without iterative calculation.Compared with the traditional PSO(Particle swarm optimization algorithm)and GA(Genetic algorithm),it can obtain faster response speed.This method can provide ideas for selecting processing parameters in industrial production.While guaranteeing the characteristic information is similar,this approach can select processing parameters which is the most appropriate for the production process and a lot of time can be saved.
基金supported in part by the National Natural Science Foundation of China under Grant 51907116in part sponsored by Natural Science Foundation of Shanghai 22ZR1425400sponsored by Shanghai Rising-Star Program 23QA1404000.
文摘Amidst the swift advancement of new power systems and electric vehicles,inverter-fed machines have progressively materialized as a pivotal apparatus for efficient energy conversion.Stator winding turn insulation failure is the root cause of inverter-fed machine breakdown.The online monitoring of turn insulation health can detect potential safety risks promptly,but faces the challenge of weak characteristics of turn insulation degradation.This study proposes an innovative method to evaluate the turn insulation state of inverter-fed machines by utilizing the fractional Fourier transform with a Mel filter(FrFT-Mel).First,the sensitivity of the high-frequency(HF)switching oscillation current to variations in turn insulation was analyzed within the fractional domain.Subsequently,an improved Mel filter is introduced,and its structure and parameters are specifically designed based on the features intrinsic to the common-mode impedance resonance point of the electrical machine.Finally,an evaluation index was proposed for the turn insulation state of inverter-fed machines.Experimental results on a 3kW permanent magnet synchronous machine(PMSM)demonstrate that the proposed FrFT-Mel method significantly enhances the sensitivity of turn insulation state perception by approximately five times,compared to the traditional Fourier transform method.
基金the National Science and Technology Major Project(Grant No.2017-VII-0011-0106)Natural Science Foundation of Heilongjiang Province(Grant No.ZD2019A001).
文摘Experimental investigations on dynamic in-plane compressive behavior of a plain weave composite were performed using the split Hopkinson pressure bar. A quantitative criterion for calculating the constant strain rate of composites was established. Then the upper limit of strain rate, restricted by stress equilibrium and constant loading rate, was rationally estimated and confirmed by tests. Within the achievable range of 0.001/s-895/s, it was found that the strength increased first and subsequently decreased as the strain rate increased. This feature was also reflected by the turning point(579/s) of the bilinear model for strength prediction. The transition in failure mechanism, from local opening damage to completely splitting destruction, was mainly responsible for such strain rate effects. And three major failure modes were summarized under microscopic observations: fiber fracture, inter-fiber fracture, and interface delamination. Finally, by introducing a nonlinear damage variable, a simplified ZWT model was developed to characterize the dynamic mechanical response. Excellent agreement was shown between the experimental and simulated results.
文摘Since the 1990s the so-called spatial turn has brought back space and topography into the discussion within historical studies,particular ancient studies.This survey reviews current trends and developments within the field and offers some perspectives on possible future developments related to space,material,objects,their agency,and frames.
基金supported by the Key Projects of National Social Science Foundation of China(Grant No.13AKS005)
文摘The concept of eco-civilization in China now is a hot issue.It has drawn sufficient attention from all walks of life,both in industry and academia.Not only Chinese domestic researcher focus on this area,but also many Western contributors shed light on this concept.For example,Arran E.Gare(1995),whose work aims to search for the roots of the global ecological crisis,and the cultural conditions to overcome it,and he reveals that environmental awareness has undoubtedly grown over the last two decades.The purpose of this research is to explore the core tenets and criteria of Community-based Ecotourism(CBET),environmental/eco-awareness and examine its contribution to Chinese eco-civilization,to voice Chinese's contribution to the Western world as ecological civilization represents the most advanced and sustainable mode of civilization in human history,and how to use ecological civilization philosophy to guide the develop of CBET in China,and in return,how to integrate concepts of CBET,environmental/eco-awareness with the process of Chinese eco-civilization nowadays.
文摘The construction of eco-civilization is an important part of socialist construction in China, and its achievements are related to the cultivation and effective implementation of the concept of sustainable development. In his report to the Nineteenth National Congress, President Xi Jin-ping pointed out that the construction of eco-civilization is an important content that affects our country and the global ecological environment. Clear ideas and measures to solve the people's needs for a better life and development imbalance between the contradictions. This paper expounds the relationship between ideological and political education and eco-civilization, and analyzes the role of modern ideological and political education in the construction of eco-civilization. The purpose of this paper is to clarify the modern ideological and political education and the construction of eco-civilization. The mutual relations lay the foundation for giving play to the role of modern ideological and political education in the construction of eco-civilization.
文摘We try to inject the idea of marine eco-civilization into marine management. By enriching connotation of marine management,the idea of marine management is improved by combining ecology,sociology and management. Current marine management in China has many problems. From the angle of enhancing marine eco-civilization construction,we put forward that marine area in whole country needs to be planned by taking marine eco-civilization as starting point,regional marine management idea should be enhanced,and division of marine management unit should be innovated,finally realizing innovation of marine management mechanism and marine sustainable development.
基金supported in part by the National Science Fund for Excellent Young Scholars of China (62222317)the National Natural Science Foundation of China (61973319)+4 种基金the Funds for International Cooperation and Exchange of the National Natural Science Foundation of China (61860206014)111 Project of China (B17048)Science and Technology Innovation Program of Hunan Province (2022WZ1001)the Natural Science Foundation of Changsha (kq2208287)the Postdoctoral Fund of Central South University (22022136)。
文摘This article proposes an integral-based event-triggered attack-resilient control method for the aircraft-on-ground(AoG) synergistic turning system with uncertain tire cornering stiffness under stochastic deception attacks. First, a novel AoG synergistic turning model is established with synergistic reverse steering of the front and main wheels to decrease the steering angle of the AoG fuselage, thus reducing the steady-state error when it follows a path with some large curvature. Considering that the tire cornering stiffness of the front and main wheels vary during steering, a dynamical observer is designed to adaptively identify them and estimate the system state at the same time.Then, an integral-based event-triggered mechanism(I-ETM) is synthesized to reduce the transmission frequency at the observerto-controller end, where stochastic deception attacks may occur at any time with a stochastic probability. Moreover, an attackresilient controller is designed to guarantee that the closed-loop system is robust L2-stable under stochastic attacks and external disturbances. A co-design method is provided to get feasible solutions for the observer, controller, and I-ETM simultaneously. An optimization program is further presented to make a tradeoff between the robustness of the control scheme and the saving of communication resources. Finally, the low-and high-probability stochastic deception attacks are considered in the simulations. The results have illustrated that the AoG synergistic turning system with the proposed control method follows a path with some large curvature well under stochastic deception attacks. Furthermore,compared with the static event-triggered mechanisms, the proposed I-ETM has demonstrated its superiority in saving communication resources.
文摘This paper explores four issues concerning aesthetics. First is the groundless concept of eco-aesthetics. In nature, aesthetics is the outcome of civilization and aesthetic appreciation is a process of human's self-affirmation. Fundamentally, ecology is the opposite of civilization. Ecology is beautiful only when it benefits humans and civilizations. The concept of ecological beauty is groundless and what exists can only be the beauty of eco-civilization. Second is the symbiosis of ecology and civilization, which is the very essence of eco-civilization beauty. Third is simplicity, which is the defining beauty of eco-civilization aesthetics and originates from agricultural civilizations. Such an aesthetic view was negated by industrial civilizations and later realized self-renewal through "negation of negation. " Today, simplicity has become the defining beauty in the era of eco-civilizations. Frugality is the core of simplicity and it carries different connotations in different eras. In the era of agricultural civilizations, frugality was for wealth accumulation, while in the era of eco-civilizations frugality is for resource conservation. Fourth is the construction of eco-civilization aesthetics of which there are three noteworthy aspects; re-establishing the divinity of nature & advocating nature worship, re-humanizing and re-building trust in technology, and improving the quality of the "habitat for humanity. " The community of eco-civilization is the biggest ever shared homeland featuring harmonious co-existence between humans and nature. The aesthetics of eco-civilization are the aesthetics of the human homeland. "Happy living and dwelling" is an eternal theme of human aesthetics. When it comes to the era of eco-civilizations, however, this theme should be added with a prefix, i.e. "eco-" to form a new concept ─ "happy eco-living and dwelling."
基金supported by the National Development and Reform Commission of China(Grant NO.201209)
文摘This paper is devoted to the analysis and comparison of eco-civilization construction modes in China and major developed western countries, which mainly focuses on the typical advanced related ecocivilization construction modes in different countries, cities or counties. Finally, it makes a comparative analysis at home and abroad, draws the conclusion and puts forward some main countermeasures and suggestions for China's eco-civilization construction on the basis of the existing research.
文摘The report of the Nineteenth National Congress of the Communist Party of China clearly points out that we should speed up the reform of the ecological civilization system and build a beautiful China.Guizhou Province is one of the first demonstration zones of ecological civilization established by the State Council and themacro-ecological strategy is one of the three strategic actions of Guizhou Province.
文摘From July 13 to 14,the“2019 China Eco-Civilization Construction Forum”,jointly sponsored by Chinese Ecological Economics Association and the journal of Ecological Economy and hosted by School of Economics,Guizhou University was held in Guiyang City,Guizhou Province.The theme of the conference is Ecological Economy and Rural Revitalization.About 150 experts and scholars from more than 100 universities and research institutions attended the forum.Experts and scholars attending the meeting conducted in-depth discussions and exchanges on the system and mechanism of eco-civilization construction in the new era,ecocivilization and social responsibility,ecological economics theory and green development,rural revitalization and ecological poverty alleviation,ecological environment and ecological industry,ecological protection and ecological compensation.
基金supported by the Outstanding Action Plan of Chinese Sci-tech Journals(Grant No.OAP–C–077)。
文摘The interaction between light and temperature is known to influence the seasonal growth of trees.Traditional studies on"light"primarily focus on day length,specifically short day(SD)or long day(LD)conditions.However,little research has been conducted on the process of transitioning between SD and LD conditions.
基金supported by the the National Natural Science Foundation of Fujian Province of China (2020J01697,2020J01699).
文摘The multi-pass turning operation is one of the most commonly used machining methods in manufacturing field.The main objective of this operation is to minimize the unit production cost.This paper proposes a Gaussian quantum-behaved bat algorithm(GQBA)to solve the problem of multi-pass turning operation.The proposed algorithm mainly includes the following two improvements.The first improvement is to incorporate the current optimal positions of quantum bats and the global best position into the stochastic attractor to facilitate population diversification.The second improvement is to use a Gaussian distribution instead of the uniform distribution to update the positions of the quantum-behaved bats,thus performing a more accurate search and avoiding premature convergence.The performance of the presented GQBA is demonstrated through numerical benchmark functions and amulti-pass turning operation problem.Thirteen classical benchmark functions are utilized in the comparison experiments,and the experimental results for accuracy and convergence speed demonstrate that,in most cases,the GQBA can provide a better search capability than other algorithms.Furthermore,GQBA is applied to an optimization problem formulti-pass turning,which is designed tominimize the production cost while considering many practical machining constraints in the machining process.The experimental results indicate that the GQBA outperforms other comparison algorithms in terms of cost reduction,which proves the effectiveness of the GQBA.
基金supported by the National Natural Science Foundation of China(Grant No.52175431)the Natural Science Foundation of Tianjin of China(Grant No.22JCZDJC00730)the Scientific Research Project of Tianjin Municipal Education Commission(Grant No.2022ZD021).
文摘With the increasing use of difficult-to-machine materials in aerospace applications,machining requirements are becoming ever more rigorous.However,traditional single-point diamond turning(SPDT)can cause surface damage and tool wear.Thus,it is difficult for SPDT to meet the processing requirements,and it has significant limitations.Research indicates that supplementing SPDT with unconventional techniques can,importantly,solve problems due to the high cutting forces and poor surface quality for difficult-to-machine materials.This paper first introduces SPDT and reviews research into unconventional techniques for use with SPDT.The machining mechanism is discussed,and the main advantages and disadvantages of various methods are investigated.Second,hybrid SPDT is briefly described,which encompasses ultrasonic-vibration magnetic-field SPDT,ultrasonic-vibration laser SPDT,and ultrasonic-vibration cold-plasma SPDT.Compared with the traditional SPDT method,hybrid SPDT produces a better optical surface quality.The current status of research into unconventional techniques to supplement SPDT is then summarized.Finally,future development trends and the application prospects of unconventional assisted SPDT are discussed.
基金National Natural Science Foundation of China(Nos.52175430,51935008 and 52105478)China National Postdoctoral Program for Innovative Talents(BX20200234)Open Fund of Tianjin Key Laboratory of Equipment Design and Manufacturing Technology(EDMT)for the support of this work。
文摘Polycrystalline materials are extensively employed in industry.Its surface roughness significantly affects the working performance.Material defects,particularly grain boundaries,have a great impact on the achieved surface roughness of polycrystalline materials.However,it is difficult to establish a purely theoretical model for surface roughness with consideration of the grain boundary effect using conventional analytical methods.In this work,a theoretical and deep learning hybrid model for predicting the surface roughness of diamond-turned polycrystalline materials is proposed.The kinematic–dynamic roughness component in relation to the tool profile duplication effect,work material plastic side flow,relative vibration between the diamond tool and workpiece,etc,is theoretically calculated.The material-defect roughness component is modeled with a cascade forward neural network.In the neural network,the ratio of maximum undeformed chip thickness to cutting edge radius RT S,work material properties(misorientation angle θ_(g) and grain size d_(g)),and spindle rotation speed n s are configured as input variables.The material-defect roughness component is set as the output variable.To validate the developed model,polycrystalline copper with a gradient distribution of grains prepared by friction stir processing is machined with various processing parameters and different diamond tools.Compared with the previously developed model,obvious improvement in the prediction accuracy is observed with this hybrid prediction model.Based on this model,the influences of different factors on the surface roughness of polycrystalline materials are discussed.The influencing mechanism of the misorientation angle and grain size is quantitatively analyzed.Two fracture modes,including transcrystalline and intercrystalline fractures at different RTS values,are observed.Meanwhile,optimal processing parameters are obtained with a simulated annealing algorithm.Cutting experiments are performed with the optimal parameters,and a flat surface finish with Sa 1.314 nm is finally achieved.The developed model and corresponding new findings in this work are beneficial for accurately predicting the surface roughness of polycrystalline materials and understanding the impacting mechanism of material defects in diamond turning.