Marine services-ranging from ocean tourism and maritime transport to public marine services-have become a powerful driver of China’s ocean economy.In 2024,the country’s gross ocean product(GOP)exceeded 10 trillion y...Marine services-ranging from ocean tourism and maritime transport to public marine services-have become a powerful driver of China’s ocean economy.In 2024,the country’s gross ocean product(GOP)exceeded 10 trillion yuan(US$1.4 trillion)for the first time,with marine services contributing 6.28 trillion yuan(US$880 billion),or 59.6 percent of the total.Among them,marine tourism and maritime transport accounted for the lion’s share.展开更多
In late October,the 17th China Cruise Shipping Conference(CCS17)kicked o!in Binhai New Area on the eastern coast of north China’s Tianjin Municipality.Themed“Developing New Quality Productive Forces in the Cruise In...In late October,the 17th China Cruise Shipping Conference(CCS17)kicked o!in Binhai New Area on the eastern coast of north China’s Tianjin Municipality.Themed“Developing New Quality Productive Forces in the Cruise Industry for a New Chapter of a Strong Maritime Country,”the three-day event included a series of meetings including the Policy and Economy Forum,the Industry Leader Forum,the Government and Enterprises Roundtable Talk,the Asian Cruise Port Forum,the Cruise Construction,Maintenance and Supporting Industries Forum,the China Cruise Talents Education and Development Summit,the Cruise Inbound Tourism Forum&Tianjin Cruise Cooperation Roundtable Talk,the New Brand and New Route Promotion Conference,and the Cruise Procurement and Supply Meeting.展开更多
The cruising market is booming in China, and both motivation and intention are the most important aspects in the field of study on the cruising passengers＇ behaviors. The research purpose of this paper is to identify...The cruising market is booming in China, and both motivation and intention are the most important aspects in the field of study on the cruising passengers＇ behaviors. The research purpose of this paper is to identify the motivation factors of the cruising passengers in China and their impact on the cruising intention. Based on the push-pull model, this paper indentified the motivation factors, including intrinsic ones and extrinsic ones, and put forward the research model. The intrinsic motivation factors include relaxation, socialization, family bonding, and social recognition, whereas the extrinsic motivation factors include entertainment and ashore tour. Having collected data through survey and analyzed them by the statistic methodology, this paper found that the motivation factors of relaxation, family bonding, entertainment, and ashore tour have a positive impact on the cruising intention, and the impact of relaxation is significant. By contrast, the motivation factors of socialization and social recognition are not positively associated with the cruising intention.展开更多
The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen e...The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called ＂zero power input＂ electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC （fuel cell） and electrolytic cell stacks, both of which are commercially available.展开更多
Taxi drivers' cruising patterns are learnt with GPS trajectory data collected in Shenzhen, China. By employing Ripley's K function, the impacts of land use and pick-up experience on taxis' cruising behavio...Taxi drivers' cruising patterns are learnt with GPS trajectory data collected in Shenzhen, China. By employing Ripley's K function, the impacts of land use and pick-up experience on taxis' cruising behavior are investigated concerning about both intensity of influence and radius of influence. The results indicate that, in general, taxi drivers tend to learn more from land use characteristics than from pick-up experience. The optimal radius of influence of land use points and previous pick-up points is 14.18 km and 9.93 km, respectively. The findings also show that the high-earning drivers or thorough drivers pay more attention to land use characteristics and tend to cruise in high-density area, while the low-earning drivers or focus drivers prefer to learn more from previous pick-up experience and select the area which is far away from the high-density area. These findings facilitate the development of measures of managing taxi's travel behavior by providing useful insights into taxis' cruising patterns. The results also provide useful advice for taxi drivers to make efficient cruising decision, which will contribute to the improvement of cruising efficiency and the reduction of negative effects.展开更多
On-board electric power generation in the absence of external energy may be sufficient to realize tough electric vehicles.The method to charge the Li-ion battery modules in the present investigation differs from the c...On-board electric power generation in the absence of external energy may be sufficient to realize tough electric vehicles.The method to charge the Li-ion battery modules in the present investigation differs from the conventional single voltage source scheme in that the power requirement is only 12%of the power required for typical direct voltage applications.This method utilizes the ESI-PSC(electrostatic-induction potential-superposed electrolytic charge).The on-board electric power generation system is an identical twin of battery modules that function in ESI-PSC mode,in which the performance can be explained through consecutive cycles of field-induced charge and discharge between two batteries.When the charge of one battery is terminated,it becomes responsible for both the power to recharge the other battery and the power to drive the motor.This power generation system works with zero energy input,zero matter input and zero emission,without violating the laws of thermodynamics.The commercially available Li-ion battery modules and power control systems enable the realization of this type of EVs(electric vehicles).A simulation based on the official standard cruising mode(JCO08)showed that an electric vehicle with an on-board twin of 13.2 kWh energy capacity modules can travel 132 km before switching from charge to discharge.展开更多
The realization of a clean automobile society would require electrically-powered propulsion systems in vehicles.In recent years,electric vehicles have attracted considerable attention from the perspective of utilizing...The realization of a clean automobile society would require electrically-powered propulsion systems in vehicles.In recent years,electric vehicles have attracted considerable attention from the perspective of utilizing electricity generated from natural sources,such as solar and wind power.The propulsion method considered in the present investigation differs from the conventional off-board energy scheme in a manner such that pure stoichiometric H2/O2 fuels for fuel cells are generated on-board during vehicle operation.In this method,energy conversion occurs by means of ESI-PSE(electrostatic-induction potential-superposed electrolysis).If a quasi-static process is assumed,the theoretical power requirement to produce pure stoichiometric H2/O2 fuels is only 17%of the total energy required owing to a new method for supplying power to the EC(electrolytic cell).If an ESI-PSE EC is combined with a fuel cell(FC)to form an energy cycle,a HREG(hydrogen redox electric power generator)that uses solid PEMs(polymer electrolyte membranes)for the EC as well as the FC can be realized.According to calculations based on data from the operational conditions of commercially available ECs and FCs,more than 70%of the power delivered from the FC can be extracted for driving a motor constantly while a car is in motion.Because of energy self-sustainability on the HREG side,the power control system should not have any power loss.This propulsion system will realize tough vehicles that can continue running at a top speed at long unlimited cruising range.展开更多
The taxi drivers' cruising pattern was learned using GPS trajectory data collected in Shenzhen,China.By employing zero-inflated Poisson model,the impacts of land use and previous pick-up experience on cruising dec...The taxi drivers' cruising pattern was learned using GPS trajectory data collected in Shenzhen,China.By employing zero-inflated Poisson model,the impacts of land use and previous pick-up experience on cruising decision were measured.The cruising strategies of different types of drivers as well as the top one driver were examined.The results indicate that both land use and previous pick-up experience affect travel behavior with the former's influence(7.07×10-4 measured by one of the coefficients in zero-inflated Poisson model) being greater than the latter's(4.58×10-5) in general,but the comparison also varies across the types of drivers.Besides,taxi drivers' day-to-day learning feature is also proved by the results.According to comparison of the cruising behavior of the most efficient and inefficient driver,an efficient cruising strategy was proposed,that is,obeying the distribution of land use in choice of cruising area,while learning from pick-up experience in selection of detailed cruising location.By learning taxi drivers' cruising pattern,the development of measures of regulating travel behaviors is facilitated,important factor for traffic organization and planning is identified,and an efficient cruising strategy for taxi drivers is provided.展开更多
The design of wide-range high-efficiency aerodynamic configurations is one of the most important key technologies in the research of near-space hypersonic vehicles.A double-sided intake configuration with different in...The design of wide-range high-efficiency aerodynamic configurations is one of the most important key technologies in the research of near-space hypersonic vehicles.A double-sided intake configuration with different inlets on the upper and lower surfaces is proposed to adapt to widerange flight.Firstly,the double-sided intake configuration’s design method and flight profile are delineated.Secondly,Computational Fluid Dynamics(CFD)numerical simulation based on multi-Graphics Processing Unit(GPU)parallel computing is adopted to evaluate the vehicle’s performance comprehensively,aiming to verify the feasibility of the proposed scheme.This evaluation encompasses a wide-range basic aerodynamic characteristics,inlet performance,and heat flux at critical locations.The results show that the inlets of the designed integration configuration can start up across Mach number 3.5 to 8.The vehicle possesses multi-point cruising capability by flipping the fuselage.Simultaneously,a 180°rotation of the fuselage can significantly decrease the heat accumulation on the lower surface of the vehicle,particularly at the inlet lip,further decreasing the temperature gradient across the vehicle structure.This study has some engineering value for the aerodynamic configuration design of wide-range vehicles.However,further study reveals that the flow phenomena at the intersection of two inlets are complex,posing potential adverse impacts on propulsion efficiency.Therefore,it is imperative to conduct additional research to delve into this matter comprehensively.展开更多
Civil aviation is one of the industries facing the greatest challenge in reaching carbon neutrality by the middle of this century,and this sector also contributes to adverse impacts on the regional air quality and hum...Civil aviation is one of the industries facing the greatest challenge in reaching carbon neutrality by the middle of this century,and this sector also contributes to adverse impacts on the regional air quality and human health.China exhibits the second highest air passenger turnover worldwide.Our understanding of civil aviation emissionsmust be urgently enhanced,and themitigation potential should be explored.In this study,on the basis of real domestic flight information for 2019,we built a greenhouse gas and air pollution emission inventory for the civil aviation sector in China with the fuel flowmethod based on the cruise and other phases.We thoroughly analyzed emissions by region,aircraft and engine types,and aircraft age,based on which we designed four measures to evaluate the abatement potential.We found that the hydrocarbon(HC),CO,NO_(x),SO_(2),particulate matter(PM)and CO_(2)emissions in 2019 reached 79.9 kt(95%CI[51.6–114.5]),176.3 kt(95%CI[114.5–248.2]),304.2 kt(95%CI[203.4–420.7]),23.2 kt(95%CI[14.2–33.7]),1.0 kt(95%CI[0.61–1.44])and 87.0 Mt(95%CI[57.4–119.6]),respectively.The cruise phase was the major emission phase,accounting for 67%-87%of the total pollutant emissions.If four measures were jointly implemented,the HC,CO,NO_(x),SO_(2),PM and CO_(2)emissions could be reduced by 61%,54%,55%,45%,32%and 38%,respectively.Utilizing lower-emission aircraft and switching travel modes could substantially reduce civil aviation emissions in China.展开更多
Tour Overview.“Yangtze River Fantasy Tour-Charm of the Yangtze”is a carefully crafted 6-night,7-day journey for you to fully experience the endless charm of China's Yangtze River.On this trip,tourists will embar...Tour Overview.“Yangtze River Fantasy Tour-Charm of the Yangtze”is a carefully crafted 6-night,7-day journey for you to fully experience the endless charm of China's Yangtze River.On this trip,tourists will embark on a top luxury cruise ship on China,s inland rivers,sailing through the Yangtze River,enjoying comfort and luxury.The modern design and complete facilities of the cruise ship not only provide first-class accommodation but also offer a variety of onboard entertainment activities,filling your journey with laughter and joy.展开更多
Wireless communication-enabled Cooperative Adaptive Cruise Control(CACC)is expected to improve the safety and traffic capacity of vehicle platoons.Existing CACC considers a conventional communication delay with fixed ...Wireless communication-enabled Cooperative Adaptive Cruise Control(CACC)is expected to improve the safety and traffic capacity of vehicle platoons.Existing CACC considers a conventional communication delay with fixed Vehicular Communication Network(VCN)topologies.However,when the network is under attack,the communication delay may be much higher,and the stability of the system may not be guaranteed.This paper proposes a novel communication Delay Aware CACC with Dynamic Network Topologies(DADNT).The main idea is that for various communication delays,in order to maximize the traffic capacity while guaranteeing stability and minimizing the following error,the CACC should dynamically adjust the VCN network topology to achieve the minimum inter-vehicle spacing.To this end,a multi-objective optimization problem is formulated,and a 3-step Divide-And-Conquer sub-optimal solution(3DAC)is proposed.Simulation results show that with 3DAC,the proposed DADNT with CACC can reduce the inter-vehicle spacing by 5%,10%,and 14%,respectively,compared with the traditional CACC with fixed one-vehicle,two-vehicle,and three-vehicle look-ahead network topologies,thereby improving the traffic efficiency.展开更多
This paper introduces an innovative approach to the deployment of folding wings on cruise missiles,aiming to overcome the issues associated with explosive devices.The proposed solution involves employing NiTi shape me...This paper introduces an innovative approach to the deployment of folding wings on cruise missiles,aiming to overcome the issues associated with explosive devices.The proposed solution involves employing NiTi shape memory wires for a nonexplosive self-deploying wing mechanism.The fundamental concept of the design revolves around the utilization of NiTi wires,which contract upon electric heating.This contraction action severs the shear pin,consequently releasing the folded wings.The operational performance of the NiTi wire is thoroughly examined through a series of electro-thermo-mechanical tests,offering valuable insights for selecting the appropriate wire material.Moreover,the mechanical dynamics involved in the self-deploying process are elucidated through finite element simulations.The simulations highlight that the thermally-induced phase transformation within the NiTi wires generates substantial actuation forces,exceeding 700 N,and strokes of over 6 mm.These forces are deemed sufficient for breaking the aluminum shear pin and effecting wing deployment.The proposed mechanism’s practical viability is substantiated through prototype tests,which conclusively establish the superiority of the nonexplosive self-deploying wing mechanism when compared to conventional methods.The experimental outcomes underscore the mechanism’s capability to markedly reduce overload stress while remaining compliant with the designated requirements and constraints.展开更多
A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the ...A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the vibrated velocity in the stern plate and main engine foundations is tested during the trial trip. Then, the excited force of the propeller and main engine is derived using the vibrated velocity and admittance matrix.Based on the excited force, the cabin-simulated vibrated velocity is compared with the tested vibrated velocity, and the tolerance is within the allowable scope in engineering. Loading the excited forces on the boundary element model, the distribution characteristics of sound level underwater are analyzed. Then, forces excited by the main engine and propeller are loaded on the model, and the contribution ratio of excitation sources to underwater acoustic radiation is analyzed. The result provides a reference for vibration assessment in the early stage and control in the late stage.展开更多
文摘Marine services-ranging from ocean tourism and maritime transport to public marine services-have become a powerful driver of China’s ocean economy.In 2024,the country’s gross ocean product(GOP)exceeded 10 trillion yuan(US$1.4 trillion)for the first time,with marine services contributing 6.28 trillion yuan(US$880 billion),or 59.6 percent of the total.Among them,marine tourism and maritime transport accounted for the lion’s share.
文摘In late October,the 17th China Cruise Shipping Conference(CCS17)kicked o!in Binhai New Area on the eastern coast of north China’s Tianjin Municipality.Themed“Developing New Quality Productive Forces in the Cruise Industry for a New Chapter of a Strong Maritime Country,”the three-day event included a series of meetings including the Policy and Economy Forum,the Industry Leader Forum,the Government and Enterprises Roundtable Talk,the Asian Cruise Port Forum,the Cruise Construction,Maintenance and Supporting Industries Forum,the China Cruise Talents Education and Development Summit,the Cruise Inbound Tourism Forum&Tianjin Cruise Cooperation Roundtable Talk,the New Brand and New Route Promotion Conference,and the Cruise Procurement and Supply Meeting.
文摘The cruising market is booming in China, and both motivation and intention are the most important aspects in the field of study on the cruising passengers＇ behaviors. The research purpose of this paper is to identify the motivation factors of the cruising passengers in China and their impact on the cruising intention. Based on the push-pull model, this paper indentified the motivation factors, including intrinsic ones and extrinsic ones, and put forward the research model. The intrinsic motivation factors include relaxation, socialization, family bonding, and social recognition, whereas the extrinsic motivation factors include entertainment and ashore tour. Having collected data through survey and analyzed them by the statistic methodology, this paper found that the motivation factors of relaxation, family bonding, entertainment, and ashore tour have a positive impact on the cruising intention, and the impact of relaxation is significant. By contrast, the motivation factors of socialization and social recognition are not positively associated with the cruising intention.
文摘The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called ＂zero power input＂ electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC （fuel cell） and electrolytic cell stacks, both of which are commercially available.
基金Project(NCET-14-0318) supported by the Humanity and Social Science Youth Foundation of Ministry of Education,ChinaProject supported by the Training Program for Outstanding Young Teachers in Jilin University,ChinaProject(2014M551191) supported by China Postdoctoral Science Foundation
文摘Taxi drivers' cruising patterns are learnt with GPS trajectory data collected in Shenzhen, China. By employing Ripley's K function, the impacts of land use and pick-up experience on taxis' cruising behavior are investigated concerning about both intensity of influence and radius of influence. The results indicate that, in general, taxi drivers tend to learn more from land use characteristics than from pick-up experience. The optimal radius of influence of land use points and previous pick-up points is 14.18 km and 9.93 km, respectively. The findings also show that the high-earning drivers or thorough drivers pay more attention to land use characteristics and tend to cruise in high-density area, while the low-earning drivers or focus drivers prefer to learn more from previous pick-up experience and select the area which is far away from the high-density area. These findings facilitate the development of measures of managing taxi's travel behavior by providing useful insights into taxis' cruising patterns. The results also provide useful advice for taxi drivers to make efficient cruising decision, which will contribute to the improvement of cruising efficiency and the reduction of negative effects.
文摘On-board electric power generation in the absence of external energy may be sufficient to realize tough electric vehicles.The method to charge the Li-ion battery modules in the present investigation differs from the conventional single voltage source scheme in that the power requirement is only 12%of the power required for typical direct voltage applications.This method utilizes the ESI-PSC(electrostatic-induction potential-superposed electrolytic charge).The on-board electric power generation system is an identical twin of battery modules that function in ESI-PSC mode,in which the performance can be explained through consecutive cycles of field-induced charge and discharge between two batteries.When the charge of one battery is terminated,it becomes responsible for both the power to recharge the other battery and the power to drive the motor.This power generation system works with zero energy input,zero matter input and zero emission,without violating the laws of thermodynamics.The commercially available Li-ion battery modules and power control systems enable the realization of this type of EVs(electric vehicles).A simulation based on the official standard cruising mode(JCO08)showed that an electric vehicle with an on-board twin of 13.2 kWh energy capacity modules can travel 132 km before switching from charge to discharge.
文摘The realization of a clean automobile society would require electrically-powered propulsion systems in vehicles.In recent years,electric vehicles have attracted considerable attention from the perspective of utilizing electricity generated from natural sources,such as solar and wind power.The propulsion method considered in the present investigation differs from the conventional off-board energy scheme in a manner such that pure stoichiometric H2/O2 fuels for fuel cells are generated on-board during vehicle operation.In this method,energy conversion occurs by means of ESI-PSE(electrostatic-induction potential-superposed electrolysis).If a quasi-static process is assumed,the theoretical power requirement to produce pure stoichiometric H2/O2 fuels is only 17%of the total energy required owing to a new method for supplying power to the EC(electrolytic cell).If an ESI-PSE EC is combined with a fuel cell(FC)to form an energy cycle,a HREG(hydrogen redox electric power generator)that uses solid PEMs(polymer electrolyte membranes)for the EC as well as the FC can be realized.According to calculations based on data from the operational conditions of commercially available ECs and FCs,more than 70%of the power delivered from the FC can be extracted for driving a motor constantly while a car is in motion.Because of energy self-sustainability on the HREG side,the power control system should not have any power loss.This propulsion system will realize tough vehicles that can continue running at a top speed at long unlimited cruising range.
基金Project(50908099)supported by the National Natural Science Foundation of ChinaProject(201104493)supported by the Doctoral Program of Higher Education of China
文摘The taxi drivers' cruising pattern was learned using GPS trajectory data collected in Shenzhen,China.By employing zero-inflated Poisson model,the impacts of land use and previous pick-up experience on cruising decision were measured.The cruising strategies of different types of drivers as well as the top one driver were examined.The results indicate that both land use and previous pick-up experience affect travel behavior with the former's influence(7.07×10-4 measured by one of the coefficients in zero-inflated Poisson model) being greater than the latter's(4.58×10-5) in general,but the comparison also varies across the types of drivers.Besides,taxi drivers' day-to-day learning feature is also proved by the results.According to comparison of the cruising behavior of the most efficient and inefficient driver,an efficient cruising strategy was proposed,that is,obeying the distribution of land use in choice of cruising area,while learning from pick-up experience in selection of detailed cruising location.By learning taxi drivers' cruising pattern,the development of measures of regulating travel behaviors is facilitated,important factor for traffic organization and planning is identified,and an efficient cruising strategy for taxi drivers is provided.
基金co-supported by the Foundation of National Key Laboratory of Science and Technology on Aerodynamic Design and Research,China(No.614220121020114)the Key R&D Projects of Hunan Province,China(No.2023GK2022)。
文摘The design of wide-range high-efficiency aerodynamic configurations is one of the most important key technologies in the research of near-space hypersonic vehicles.A double-sided intake configuration with different inlets on the upper and lower surfaces is proposed to adapt to widerange flight.Firstly,the double-sided intake configuration’s design method and flight profile are delineated.Secondly,Computational Fluid Dynamics(CFD)numerical simulation based on multi-Graphics Processing Unit(GPU)parallel computing is adopted to evaluate the vehicle’s performance comprehensively,aiming to verify the feasibility of the proposed scheme.This evaluation encompasses a wide-range basic aerodynamic characteristics,inlet performance,and heat flux at critical locations.The results show that the inlets of the designed integration configuration can start up across Mach number 3.5 to 8.The vehicle possesses multi-point cruising capability by flipping the fuselage.Simultaneously,a 180°rotation of the fuselage can significantly decrease the heat accumulation on the lower surface of the vehicle,particularly at the inlet lip,further decreasing the temperature gradient across the vehicle structure.This study has some engineering value for the aerodynamic configuration design of wide-range vehicles.However,further study reveals that the flow phenomena at the intersection of two inlets are complex,posing potential adverse impacts on propulsion efficiency.Therefore,it is imperative to conduct additional research to delve into this matter comprehensively.
基金supported by the National Natural Science Foundation of China(Nos.42375171 and 42105157)the Interdisciplinary Research Project for Young Teachers of USTB(No.06600083)+1 种基金Energy Foundation(Nos.G-2109-33379 and G-2306-34754)the Fundamental Research Funds for the Central Universities(No.06500166).
文摘Civil aviation is one of the industries facing the greatest challenge in reaching carbon neutrality by the middle of this century,and this sector also contributes to adverse impacts on the regional air quality and human health.China exhibits the second highest air passenger turnover worldwide.Our understanding of civil aviation emissionsmust be urgently enhanced,and themitigation potential should be explored.In this study,on the basis of real domestic flight information for 2019,we built a greenhouse gas and air pollution emission inventory for the civil aviation sector in China with the fuel flowmethod based on the cruise and other phases.We thoroughly analyzed emissions by region,aircraft and engine types,and aircraft age,based on which we designed four measures to evaluate the abatement potential.We found that the hydrocarbon(HC),CO,NO_(x),SO_(2),particulate matter(PM)and CO_(2)emissions in 2019 reached 79.9 kt(95%CI[51.6–114.5]),176.3 kt(95%CI[114.5–248.2]),304.2 kt(95%CI[203.4–420.7]),23.2 kt(95%CI[14.2–33.7]),1.0 kt(95%CI[0.61–1.44])and 87.0 Mt(95%CI[57.4–119.6]),respectively.The cruise phase was the major emission phase,accounting for 67%-87%of the total pollutant emissions.If four measures were jointly implemented,the HC,CO,NO_(x),SO_(2),PM and CO_(2)emissions could be reduced by 61%,54%,55%,45%,32%and 38%,respectively.Utilizing lower-emission aircraft and switching travel modes could substantially reduce civil aviation emissions in China.
文摘Tour Overview.“Yangtze River Fantasy Tour-Charm of the Yangtze”is a carefully crafted 6-night,7-day journey for you to fully experience the endless charm of China's Yangtze River.On this trip,tourists will embark on a top luxury cruise ship on China,s inland rivers,sailing through the Yangtze River,enjoying comfort and luxury.The modern design and complete facilities of the cruise ship not only provide first-class accommodation but also offer a variety of onboard entertainment activities,filling your journey with laughter and joy.
基金supported by the National Natural Science Foundation of China under Grant U21A20449in part by Jiangsu Provincial Key Research and Development Program under Grant BE2021013-2。
文摘Wireless communication-enabled Cooperative Adaptive Cruise Control(CACC)is expected to improve the safety and traffic capacity of vehicle platoons.Existing CACC considers a conventional communication delay with fixed Vehicular Communication Network(VCN)topologies.However,when the network is under attack,the communication delay may be much higher,and the stability of the system may not be guaranteed.This paper proposes a novel communication Delay Aware CACC with Dynamic Network Topologies(DADNT).The main idea is that for various communication delays,in order to maximize the traffic capacity while guaranteeing stability and minimizing the following error,the CACC should dynamically adjust the VCN network topology to achieve the minimum inter-vehicle spacing.To this end,a multi-objective optimization problem is formulated,and a 3-step Divide-And-Conquer sub-optimal solution(3DAC)is proposed.Simulation results show that with 3DAC,the proposed DADNT with CACC can reduce the inter-vehicle spacing by 5%,10%,and 14%,respectively,compared with the traditional CACC with fixed one-vehicle,two-vehicle,and three-vehicle look-ahead network topologies,thereby improving the traffic efficiency.
基金Supported by National Natural Science Foundation of China(Grant No.12372156).
文摘This paper introduces an innovative approach to the deployment of folding wings on cruise missiles,aiming to overcome the issues associated with explosive devices.The proposed solution involves employing NiTi shape memory wires for a nonexplosive self-deploying wing mechanism.The fundamental concept of the design revolves around the utilization of NiTi wires,which contract upon electric heating.This contraction action severs the shear pin,consequently releasing the folded wings.The operational performance of the NiTi wire is thoroughly examined through a series of electro-thermo-mechanical tests,offering valuable insights for selecting the appropriate wire material.Moreover,the mechanical dynamics involved in the self-deploying process are elucidated through finite element simulations.The simulations highlight that the thermally-induced phase transformation within the NiTi wires generates substantial actuation forces,exceeding 700 N,and strokes of over 6 mm.These forces are deemed sufficient for breaking the aluminum shear pin and effecting wing deployment.The proposed mechanism’s practical viability is substantiated through prototype tests,which conclusively establish the superiority of the nonexplosive self-deploying wing mechanism when compared to conventional methods.The experimental outcomes underscore the mechanism’s capability to markedly reduce overload stress while remaining compliant with the designated requirements and constraints.
文摘A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the vibrated velocity in the stern plate and main engine foundations is tested during the trial trip. Then, the excited force of the propeller and main engine is derived using the vibrated velocity and admittance matrix.Based on the excited force, the cabin-simulated vibrated velocity is compared with the tested vibrated velocity, and the tolerance is within the allowable scope in engineering. Loading the excited forces on the boundary element model, the distribution characteristics of sound level underwater are analyzed. Then, forces excited by the main engine and propeller are loaded on the model, and the contribution ratio of excitation sources to underwater acoustic radiation is analyzed. The result provides a reference for vibration assessment in the early stage and control in the late stage.
