Regional turbofan aircraft,which are used for medium-short distances,have a heightened risk of high-altitude Wake Vortices(VV)because of their tail-mounted engines and high horizontal tail configurations.For some regi...Regional turbofan aircraft,which are used for medium-short distances,have a heightened risk of high-altitude Wake Vortices(VV)because of their tail-mounted engines and high horizontal tail configurations.For some regional medium-short-range turbofan aircraft,this threat is higher than that for conventionally designed aircraft.To analyze the flight safety of turbofan aircraft during cruise,this study developed a model to assess wake vortex encounters based on evolutionary high-altitude wake flow patterns.First,the high-altitude wake vortex aircraft dissipation patterns were analyzed by combining Quick Access Recorder(QAR)flight data with the wake vortex evolution model.Then,to consider the uniqueness of the medium-short-range turbofan aircraft,the severity of the wake vortex encounters was simulated using an induced roll moment coefficient.The proposed high-altitude wake vortex encounter model was able to identify and assess the highaltitude wake vortex changes,the bearing moments at different altitudes,and the atmospheric pressure conditions.Using the latest wake separation standards from the International Civil Aviation Organization(ICAO),acceptable safety wake intervals for follower aircraft in different scenarios were determined for the safety assessment.The results indicate that compared to mid and low altitudes,the high-altitude aircraft wake vortex dissipation rate is faster,the ultimate bearing moment is weaker,and the roll moment coefficient is higher,which confirm that there is elevated wake vortex encounter severity for regional turbofan aircraft.As safety is found to deteriorate when encountering wake vortices at altitudes higher than 8 km,new medium-short-range turbofan regional aircraft require higher safety margins than the latest wake separation standards.展开更多
This study investigates the relationships between exposures to ambient air pollution—specifically particulate matter 2.5 (PM_(2.5)) and its metabolites—and the risk of depression.Nonlinear and linear regression,Baye...This study investigates the relationships between exposures to ambient air pollution—specifically particulate matter 2.5 (PM_(2.5)) and its metabolites—and the risk of depression.Nonlinear and linear regression,Bayesian kernel machine regression,and toxicogenomic analysis were key approaches.PM_(2.5)exposure was positively associated with the risk of developing depression,whereas phenylglyoxylic acid exposure was negatively associated with depression risk.We found a significant overall relationship between ambient air pollution and depression,particularly at the 55th and 60th percentiles.Although statistical significance was not reached at the 65th percentile,there was a noticeable upward trend,indicating a potential association.Interestingly,no significant connection was found between a combination of metabolites from ambient air pollution and depression.PM_(2.5)and phenylglyoxylic acid emerged as the most influential compounds in the models,respectively.PM_(2.5)exposure altered the expression of 42 specific targets associated with depression,especially POMC,SCL6A4,IL6,and SOD2.The study identified specific pathways related to insulin secretion,energy metabolism,blood circulation,tube diameter,and maintenance of blood vessel diameter,as well as key molecular mechanisms involving hsa-miR-124-3p,hsa-miR-155-5p,hsa-miR-16-5p,and SP1.These mechanisms were found to underlie the etiology of depression associated with PM_(2.5)exposure.In conclusions,PM_(2.5)and phenylglyoxylic acid were found to be associated with depression.Further work is needed to gain insight into the molecular mechanisms by which these chemicals affect depression,especially pathways related to insulin secretion and blood circulation.展开更多
Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(v_(r)),axial extrac...Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(v_(r)),axial extraction velocity(v_(e))and extraction distance(L)in the formation process of air curtain,the numerical simulation method was used to analyze the rules of airflow structure evolution and the diffusion characteristics of dust particles in fully mechanized excavation tunnel.The results indicate that as v_(r) and v_(e) increase,the migration path of the wall jet of the air curtain changes into an axial direction;as L decreases,the migration distance increases accordingly.These phenomena make the airflow distribution in the working face tends to be uniform.The dust diffusion distance reduces as well,wherein,the range of the discrete area of dust particles decreases sharply,until all dust particles are concentrated in the accumulation area.On this basis,the v_(r),v_(e) and L were optimized and applied in the 63_(up) 08 fully mechanized working face.By the application of the optimal parameters,the average dust removal efficiency at the driver’s position increased by 71%.The dust concentration was reduced and the working environment had been improved effectively.展开更多
High-energy-density lithium(Li)–air cells have been considered a promising energy-storage system,but the liquid electrolyte-related safety and side-reaction problems seriously hinder their development.To address thes...High-energy-density lithium(Li)–air cells have been considered a promising energy-storage system,but the liquid electrolyte-related safety and side-reaction problems seriously hinder their development.To address these above issues,solid-state Li–air batteries have been widely developed.However,many commonly-used solid electrolytes generally face huge interface impedance inLi–air cells and also showpoor stability towards ambient air/Li electrodes.Herein,we fabricate a differentiating surface-regulated ceramic-based composite electrolyte(DSCCE)by constructing disparately LiI-containing polymethyl methacrylate(PMMA)coating and Poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)layer on both sides of Li_(1.5)Al_(0.5)Ge_(1.5)(PO_(4))_(3)(LAGP).The cathode-friendly LiI/PMMA layer displays excellent stability towards superoxide intermediates and also greatly reduces the decomposition voltage of discharge products in Li–air system.Additionally,the anode-friendly PVDF-HFP coating shows low-resistance properties towards anodes.Moreover,Li dendrite/passivation derived from liquid electrolyte-induced side reactions and air/I-attacking can be obviously suppressed by the uniformand compact composite framework.As a result,the DSCCE-based Li–air batteries possess high capacity/low voltage polarization(11,836mAh g^(-1)/1.45Vunder 500mAg^(-1)),good rate performance(capacity ratio under 1000mAg^(-1)/250mAg^(-1) is 68.2%)and longterm stable cell operation(~300 cycles at 750 mA g^(-1) with 750 mAh g^(-1))in ambient air.展开更多
Lithium-air batteries(LABs)are regarded as a next-generation energy storage option due to their relatively high energy density.The cyclic stability and lifespan of LABs are mainly influenced by the formation and decom...Lithium-air batteries(LABs)are regarded as a next-generation energy storage option due to their relatively high energy density.The cyclic stability and lifespan of LABs are mainly influenced by the formation and decomposition of lithium-based oxides at the air cathode,which not only lead to a low cathode catalytic efficiency but also restrict the electrochemical reversibility and cause side reaction problems.Carbon materials are considered key to solving these problems due to their conductivity,functional flexibility,and adjustable pore structure.This paper considers the research progress on carbon materials as air cathode catalytic materials for LABs,focusing on their structural characteristics,electrochemical behavior,and reaction mechanisms.Besides being used as air cathodes,carbon materials also show potential for being used as protective layers for metal anodes or as anode materials for LABs.展开更多
African Aviation continues to fall short of serving the demands of the fast-growing African population. For major air transport in and out of the African continent, African travellers rely mainly on non-African Airlin...African Aviation continues to fall short of serving the demands of the fast-growing African population. For major air transport in and out of the African continent, African travellers rely mainly on non-African Airlines. There is, however, one successful airline on the continent at the writing of this paper: Ethiopian Airlines and the Ethiopian Aviation Group. Why are no further successful airlines possible on a continent of 1.4 billion people (25% of the world’s population) and only a 2%-share of global air transport? At the introduction of SAATM, which is anticipated as the start of the domestic African aviation boom, most African countries seem unprepared to build a success story like Ethiopia. Transportation infrastructure in sub-Saharan Africa does not start with roads and rail but with runways and airlines. This research investigates the basic requirements needed to equip Africa with a competitive aviation industry that would contribute some 5% to the continent’s GDP and create hundreds of thousands of workplaces. Interviews with African SAATM leaders signal a slowdown in the effort to succeed. The research is also concerned about the lack of inclusion in the implementation of a NetZero CO2 emission scheme in Africa.展开更多
Flapping-Wing Air Vehicles(FWAVs)have been developed to pursue the efficient,agile,and quiet flight of flying animals.However,unlike lightweight FWAVs capable of vertical takeoff,relatively heavy FWAVs face challenges...Flapping-Wing Air Vehicles(FWAVs)have been developed to pursue the efficient,agile,and quiet flight of flying animals.However,unlike lightweight FWAVs capable of vertical takeoff,relatively heavy FWAVs face challenges in self-takeoff,which refers to taking off without both external device and energy input.In this study,a cliff-drop method is implemented for an independent takeoff of a heavy FWAV,relying solely on gravity.In the takeoff process using the cliff-drop method,the FWAV moves on the ground to a cliff edge using a wheel-driving motor and then descends from the cliff to achieve the necessary speed for flight.To demonstrate the cliff-drop method,the KAIST Robotic Hawk(KRoHawk)with a mass of 740 g and a wingspan of 120 cm is developed.The takeoff tests demonstrate that the KRoHawk,significantly heavier than the vertical-takeoff capable FWAVs,can successfully take off using the gravity-assisted takeoff method.The scalability of cliff-drop method is analyzed through simulations.When drop constraints are absent,the wheel-driving motor mass fraction for cliff-drop method remains negligible even as the vehicle's weight increases.When drop constraints are set to 4 m,FWAVs heavier than KRoHawk,weighing up to 4.4 kg,can perform the cliff-drop takeoffs with a wheel-driving motor mass fraction of less than 8%.展开更多
Clean air is fundamental to human health.Approximately 99%of the global population has been exposed to concentrations higher than the World Health Organization’s recommendations.Moreover,adverse health effects have b...Clean air is fundamental to human health.Approximately 99%of the global population has been exposed to concentrations higher than the World Health Organization’s recommendations.Moreover,adverse health effects have been observed at much lower pollution levels than previously studied.China has experienced periods of severe air pollution over the past few decades.To improve air quality and safeguard public health,the government has implemented several progressively tightened policies.Emission control policies were first proposed in 2005.展开更多
The Textile Technology Centre is the pride of Heberlein.State-of-the-art equipment and a team of top experts guarantee the highest standards of support for customers.Heberlein is the leading provider of air interlacin...The Textile Technology Centre is the pride of Heberlein.State-of-the-art equipment and a team of top experts guarantee the highest standards of support for customers.Heberlein is the leading provider of air interlacing and air texturing jets for synthetic continuous filament yarns and its clients enjoy added value in the form of practical help and guidance on textile processes and economic issues,with a special focus on filament yarn applications.展开更多
Shaoxing Shuifu Reeds is professional on producing all kinds of Air Jet Reeds and Flat Reeds,which has an annual output of 90,000 meters air-jet reeds,300,000,000 pcs of profile dents and 60,000 meters of Flat Reeds,W...Shaoxing Shuifu Reeds is professional on producing all kinds of Air Jet Reeds and Flat Reeds,which has an annual output of 90,000 meters air-jet reeds,300,000,000 pcs of profile dents and 60,000 meters of Flat Reeds,Which has been honored with China Air Jet Profile Reeds Research Center by China Textile Machinery Association in 2015.In order to reach the demands of high quality fabric and industrial textile products,the yarn is developing to high count,multicolor,various fibers,and the fabric is developing to high count,high density,environment protection.So we have researched out high density,multicolor,multinozzle,double energy saving type profile reeds to let you choose.展开更多
Direct air capture(DAC)is a negative carbon emission technology that faces challenges in scalability and practical deployment due to its exorbitant costs.Hou et al.(2017)integrated DAC technology with fertilization.A ...Direct air capture(DAC)is a negative carbon emission technology that faces challenges in scalability and practical deployment due to its exorbitant costs.Hou et al.(2017)integrated DAC technology with fertilization.A multi-bed desorption system driven by water provides a competitive and sustainable carbon source for indoor agriculture.展开更多
International freedom of the air(traffic rights)is a key resource for airlines to carry out international air transport business.An efficient and reasonable traffic right resource allocation within a country between a...International freedom of the air(traffic rights)is a key resource for airlines to carry out international air transport business.An efficient and reasonable traffic right resource allocation within a country between airlines can affect the quality of a country’s participation in international air transport.In this paper,a multi-objective mixed-integer programming model for traffic rights resource allocation is developed to minimize passenger travel mileages and maximize the number of traffic rights resources allocated to hub airports and competitive carriers.A hybrid heuristic algorithm combining the genetic algorithm and the variable neighborhood search is devised to solve the model.The results show that the optimal allocation scheme aligns with the principle of fairness,indicating that the proposed model can play a certain guiding role in and provide an innovative perspective on traffic rights resource allocation in various countries.展开更多
Carbon dioxide(CO_(2))is often monitored as a convenient yardstick for indoor air safety,yet its ability to stand in for pathogen-laden aerosols has never been settled.To probe the question,we reproduced an open-plan ...Carbon dioxide(CO_(2))is often monitored as a convenient yardstick for indoor air safety,yet its ability to stand in for pathogen-laden aerosols has never been settled.To probe the question,we reproduced an open-plan office at full scale(7.2m×5.2m×2.8m)and introduced a breathing plume that carried 4% CO_(2),together with a polydisperse aerosol spanning 0.5–10μm(1320 particles s^(−1)).Inlet air was supplied at 0.7,1.4,and 2.1 m s^(−1),and the resulting fields were simulated with a Realisable k–εRANS model coupled to Lagrangian particle tracking.Nine strategically placed probes provided validation;the calibrated solution deviated fromthe experiment by 58 ppm for CO_(2)(8.1%RMSE)and 0.008 m s^(−1)for velocity(15.7%RMSE).Despite this agreement,gas and particles behaved in sharply different ways.Room-averaged CO_(2)varied by<15%,whereas the aerosol mass rose to almost three-fold the background within slowmoving corner vortices.Sub-micron particles stayed aloft along streamlines,while those≥5μmpeeled away and settled on nearby surfaces.The divergence shows that neither the CO_(2)level nor themeanageof air,taken in isolation,delineates all high-exposure zones.We therefore recommend that ventilation design be informed by a composite diagnosis that couples gas data,size-resolved particle measurements,and rapid CFD appraisal.展开更多
Airborne microorganisms(AM)have significant environmental and health implications.Extensive studies have been conducted to investigate the factors influencing the composition and diversity of AM.However,the knowledge ...Airborne microorganisms(AM)have significant environmental and health implications.Extensive studies have been conducted to investigate the factors influencing the composition and diversity of AM.However,the knowledge of AM with anthropogenic activities has not reach a consensus.In this study,we took advantage of the dramatic decline of outdoor anthropogenic activities resulting from COVID-19 lockdown to reveal their associations.We collected airborne particulate matter before and during the lockdown period in two cities.The results showed that it was fungal diversity and communities but not bacteria obviously different between pre-lockdownand lockdown samples,suggesting that airborne fungiwere more susceptible to anthropogenic activities than bacteria.However,after the implementation of lockdown,the co-occurrence networks of both bacterial and fungal community became more complex,whichmight be due to the variation of microbial sources.Furthermore,Mantel test and correlation analysis showed that air pollutants also partly contributed to microbial alterations.Airborne fungal community was more affected by air pollutants than bacterial community.Notably,some human pathogens like Nigrospora and Arthrinium were negatively correlated with air pollutants.Overall,our study highlighted the more impacts of anthropogenic activities on airborne fungal community than bacterial community and advanced the understanding of associations between anthropogenic activities and AM.展开更多
Viruses, notably airborne viruses, are difficult to collect and detect because of the low concentrations of environmental microorganisms. Bacteriophages are frequently used in air experiments as suitable surrogates fo...Viruses, notably airborne viruses, are difficult to collect and detect because of the low concentrations of environmental microorganisms. Bacteriophages are frequently used in air experiments as suitable surrogates for human and animal viruses^([1]). Bacteriophages are non-pathogenic, so they are safe for laboratory workers and do not require specialized biological protection measures.Bacteriophages can be prepared at high titers using simple and low-cost methods.展开更多
Airports around the world commonly face challenges in managing airport slot allocation.Effective management of limited slot resources by civil aviation authority often requires redistributing requested slots among air...Airports around the world commonly face challenges in managing airport slot allocation.Effective management of limited slot resources by civil aviation authority often requires redistributing requested slots among airlines.The allocation process must operate within the prescribed capacity limits of the airport while adhering to established priorities and regulations.Additionally,ensuring market fairness is a key objective,as the value of airport slots plays a significant role in the adjustment process.This transforms the traditional time-shift-based problem into a complex multi-objective optimization problem.Addressing such complications is of significant importance to airlines,airports,and passengers alike.Due to the complexity of fairness metrics,traditional integer programming models encounter difficulties in finding effective solutions.This study proposes a neighborhood search strategy to tackle the single airport slot allocation,making it adaptable to both static and rolling capacity scenarios.Two Genetic Algorithms(GAs)are introduced,corresponding to time adjustment and sequence adjustment strategies,respectively.The GA based on the time adjustment strategy demonstrates high robustness,while the sequence adjustment strategy builds upon this GA to develop a simple heuristic algorithm that offers rapid convergence.Case studies conducted at seven airports in China confirm that all three algorithms yield high-quality adjustment solutions suitable for the majority of applications.Further,Pareto analysis reveals that these algorithms effectively balance the adjustment shifts and fairness metrics,demonstrating high practical value and broad applicability.展开更多
Air traffic flow management has been a major means for balancing air traffic demandand airport or airspace capacity to reduce congestion and flight delays.However,unpredictable fac-tors,such as weather and equipment m...Air traffic flow management has been a major means for balancing air traffic demandand airport or airspace capacity to reduce congestion and flight delays.However,unpredictable fac-tors,such as weather and equipment malfunctions,can cause dynamic changes in airport and sectorcapacity,resulting in significant alterations to optimized flight schedules and the calculated pre-departure slots.Therefore,taking into account capacity uncertainties is essential to create a moreresilient flight schedule.This paper addresses the flight pre-departure sequencing issue and intro-duces a capacity uncertainty model for optimizing flight schedule at the airport network level.The goal of the model is to reduce the total cost of flight delays while increasing the robustnessof the optimized schedule.A chance-constrained model is developed to address the capacity uncer-tainty of airports and sectors,and the significance of airports and sectors in the airport network isconsidered when setting the violation probability.The performance of the model is evaluated usingreal flight data by comparing them with the results of the deterministic model.The development ofthe model based on the characteristics of this special optimization mechanism can significantlyenhance its performance in addressing the pre-departure flight scheduling problem at the airportnetwork level.展开更多
Solid oxide cells(SOCs)are emerging devices for efficient energy storage and conversion.However,during SOC operation,gaseous chromium(Cr)species released from Fe-Cr alloy interconnect can lead to Cr deposition and poi...Solid oxide cells(SOCs)are emerging devices for efficient energy storage and conversion.However,during SOC operation,gaseous chromium(Cr)species released from Fe-Cr alloy interconnect can lead to Cr deposition and poisoning of air electrodes,causing substantial degradation in electrochemical performance and compromising the longterm stability of SOCs.This mini-review examines the mechanism of Cr deposition and poisoning in air electrodes under both fuel-cell and electrolysis modes.Furthermore,emphasis is placed on the recent advancements in strategies to mitigate Cr poisoning,offering insights into the rational design and development of active and Cr-tolerant air electrodes for SOCs.展开更多
Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage p...Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage poses challenges for the performance and stability of air electrodes.In this work,a novel high-entropy perovskite oxide La_(0.2)Pr_(0.2)Gd_(0.2)Sm_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF)is proposed and investigated as an air electrode in RSOC.The electrochemical behavior of HE-LSCF was studied as an air electrode in both fuel cell and electrolysis modes.The polarization impedance(Rp)of the HE-LSCF electrode is only 0.25Ω·cm^(2) at 800℃ in an air atmosphere.Notably,at an electrolytic voltage of 2 V and a temperature of 800℃,the current density reaches up to 1.68 A/cm^(2).The HE-LSCF air electrode exhibited excellent reversibility and stability,and its electrochemical performance remains stable after 100 h of reversible operation.With these advantages,HE-LSCF is shown to be an excellent air electrode for RSOC.展开更多
Air pollution in China covers a large area with complex sources and formation mechanisms,making it a unique place to conduct air pollution and atmospheric chemistry research.The National Natural Science Foundation of ...Air pollution in China covers a large area with complex sources and formation mechanisms,making it a unique place to conduct air pollution and atmospheric chemistry research.The National Natural Science Foundation of China’s Major Research Plan entitled“Fundamental Researches on the Formation and Response Mechanism of the Air Pollution Complex in China”(or the Plan)has funded 76 research projects to explore the causes of air pollution in China,and the key processes of air pollution in atmospheric physics and atmospheric chemistry.In order to summarize the abundant data from the Plan and exhibit the long-term impacts domestically and internationally,an integration project is responsible for collecting the various types of data generated by the 76 projects of the Plan.This project has classified and integrated these data,forming eight categories containing 258 datasets and 15 technical reports in total.The integration project has led to the successful establishment of the China Air Pollution Data Center(CAPDC)platform,providing storage,retrieval,and download services for the eight categories.This platform has distinct features including data visualization,related project information querying,and bilingual services in both English and Chinese,which allows for rapid searching and downloading of data and provides a solid foundation of data and support for future related research.Air pollution control in China,especially in the past decade,is undeniably a global exemplar,and this data center is the first in China to focus on research into the country’s air pollution complex.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U2333209,U1733203)the National Key R&D Program of China(No.2021YFF0603904)the Civil Aviation Administration of China(No.AQ20200019)。
文摘Regional turbofan aircraft,which are used for medium-short distances,have a heightened risk of high-altitude Wake Vortices(VV)because of their tail-mounted engines and high horizontal tail configurations.For some regional medium-short-range turbofan aircraft,this threat is higher than that for conventionally designed aircraft.To analyze the flight safety of turbofan aircraft during cruise,this study developed a model to assess wake vortex encounters based on evolutionary high-altitude wake flow patterns.First,the high-altitude wake vortex aircraft dissipation patterns were analyzed by combining Quick Access Recorder(QAR)flight data with the wake vortex evolution model.Then,to consider the uniqueness of the medium-short-range turbofan aircraft,the severity of the wake vortex encounters was simulated using an induced roll moment coefficient.The proposed high-altitude wake vortex encounter model was able to identify and assess the highaltitude wake vortex changes,the bearing moments at different altitudes,and the atmospheric pressure conditions.Using the latest wake separation standards from the International Civil Aviation Organization(ICAO),acceptable safety wake intervals for follower aircraft in different scenarios were determined for the safety assessment.The results indicate that compared to mid and low altitudes,the high-altitude aircraft wake vortex dissipation rate is faster,the ultimate bearing moment is weaker,and the roll moment coefficient is higher,which confirm that there is elevated wake vortex encounter severity for regional turbofan aircraft.As safety is found to deteriorate when encountering wake vortices at altitudes higher than 8 km,new medium-short-range turbofan regional aircraft require higher safety margins than the latest wake separation standards.
文摘This study investigates the relationships between exposures to ambient air pollution—specifically particulate matter 2.5 (PM_(2.5)) and its metabolites—and the risk of depression.Nonlinear and linear regression,Bayesian kernel machine regression,and toxicogenomic analysis were key approaches.PM_(2.5)exposure was positively associated with the risk of developing depression,whereas phenylglyoxylic acid exposure was negatively associated with depression risk.We found a significant overall relationship between ambient air pollution and depression,particularly at the 55th and 60th percentiles.Although statistical significance was not reached at the 65th percentile,there was a noticeable upward trend,indicating a potential association.Interestingly,no significant connection was found between a combination of metabolites from ambient air pollution and depression.PM_(2.5)and phenylglyoxylic acid emerged as the most influential compounds in the models,respectively.PM_(2.5)exposure altered the expression of 42 specific targets associated with depression,especially POMC,SCL6A4,IL6,and SOD2.The study identified specific pathways related to insulin secretion,energy metabolism,blood circulation,tube diameter,and maintenance of blood vessel diameter,as well as key molecular mechanisms involving hsa-miR-124-3p,hsa-miR-155-5p,hsa-miR-16-5p,and SP1.These mechanisms were found to underlie the etiology of depression associated with PM_(2.5)exposure.In conclusions,PM_(2.5)and phenylglyoxylic acid were found to be associated with depression.Further work is needed to gain insight into the molecular mechanisms by which these chemicals affect depression,especially pathways related to insulin secretion and blood circulation.
基金financially supported by the Natural Science Foundation of Shandong Province(ZR2020QE124,ZR2023ME031 and ZR2023ME012)Innovation Achievement Cultivation Project of Qingdao University of Technology(CLZ2022-002)National Natural Science Foundation of China(52404222 and 52374209).
文摘Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(v_(r)),axial extraction velocity(v_(e))and extraction distance(L)in the formation process of air curtain,the numerical simulation method was used to analyze the rules of airflow structure evolution and the diffusion characteristics of dust particles in fully mechanized excavation tunnel.The results indicate that as v_(r) and v_(e) increase,the migration path of the wall jet of the air curtain changes into an axial direction;as L decreases,the migration distance increases accordingly.These phenomena make the airflow distribution in the working face tends to be uniform.The dust diffusion distance reduces as well,wherein,the range of the discrete area of dust particles decreases sharply,until all dust particles are concentrated in the accumulation area.On this basis,the v_(r),v_(e) and L were optimized and applied in the 63_(up) 08 fully mechanized working face.By the application of the optimal parameters,the average dust removal efficiency at the driver’s position increased by 71%.The dust concentration was reduced and the working environment had been improved effectively.
基金supported by the National Natural Science Foundation of China(22379074)Young Science and Technology Talent Program of Inner Mongolia Province(NJYT24001)+4 种基金Natural Sciences and Engineering Research Council of Canada(NSERC)GLABAT Solid-State Battery Inc.,China Automotive Battery Research Institute Co.Ltd,Canada Research Chair Program(CRC)Canada Foundation for Innovation(CFI)Ontario Research Fundsupported by the Chinese Scholarship Council.
文摘High-energy-density lithium(Li)–air cells have been considered a promising energy-storage system,but the liquid electrolyte-related safety and side-reaction problems seriously hinder their development.To address these above issues,solid-state Li–air batteries have been widely developed.However,many commonly-used solid electrolytes generally face huge interface impedance inLi–air cells and also showpoor stability towards ambient air/Li electrodes.Herein,we fabricate a differentiating surface-regulated ceramic-based composite electrolyte(DSCCE)by constructing disparately LiI-containing polymethyl methacrylate(PMMA)coating and Poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)layer on both sides of Li_(1.5)Al_(0.5)Ge_(1.5)(PO_(4))_(3)(LAGP).The cathode-friendly LiI/PMMA layer displays excellent stability towards superoxide intermediates and also greatly reduces the decomposition voltage of discharge products in Li–air system.Additionally,the anode-friendly PVDF-HFP coating shows low-resistance properties towards anodes.Moreover,Li dendrite/passivation derived from liquid electrolyte-induced side reactions and air/I-attacking can be obviously suppressed by the uniformand compact composite framework.As a result,the DSCCE-based Li–air batteries possess high capacity/low voltage polarization(11,836mAh g^(-1)/1.45Vunder 500mAg^(-1)),good rate performance(capacity ratio under 1000mAg^(-1)/250mAg^(-1) is 68.2%)and longterm stable cell operation(~300 cycles at 750 mA g^(-1) with 750 mAh g^(-1))in ambient air.
文摘Lithium-air batteries(LABs)are regarded as a next-generation energy storage option due to their relatively high energy density.The cyclic stability and lifespan of LABs are mainly influenced by the formation and decomposition of lithium-based oxides at the air cathode,which not only lead to a low cathode catalytic efficiency but also restrict the electrochemical reversibility and cause side reaction problems.Carbon materials are considered key to solving these problems due to their conductivity,functional flexibility,and adjustable pore structure.This paper considers the research progress on carbon materials as air cathode catalytic materials for LABs,focusing on their structural characteristics,electrochemical behavior,and reaction mechanisms.Besides being used as air cathodes,carbon materials also show potential for being used as protective layers for metal anodes or as anode materials for LABs.
文摘African Aviation continues to fall short of serving the demands of the fast-growing African population. For major air transport in and out of the African continent, African travellers rely mainly on non-African Airlines. There is, however, one successful airline on the continent at the writing of this paper: Ethiopian Airlines and the Ethiopian Aviation Group. Why are no further successful airlines possible on a continent of 1.4 billion people (25% of the world’s population) and only a 2%-share of global air transport? At the introduction of SAATM, which is anticipated as the start of the domestic African aviation boom, most African countries seem unprepared to build a success story like Ethiopia. Transportation infrastructure in sub-Saharan Africa does not start with roads and rail but with runways and airlines. This research investigates the basic requirements needed to equip Africa with a competitive aviation industry that would contribute some 5% to the continent’s GDP and create hundreds of thousands of workplaces. Interviews with African SAATM leaders signal a slowdown in the effort to succeed. The research is also concerned about the lack of inclusion in the implementation of a NetZero CO2 emission scheme in Africa.
基金supported by Unmanned Vehicles Core Technology Research and Development Program through the National Research Foundation of Korea(NRF)Unmanned Vehicle Advanced Research Center(UVARC)funded by the Ministry of Science and ICT,the Republic of Korea(2020M3C1C1A01083415).
文摘Flapping-Wing Air Vehicles(FWAVs)have been developed to pursue the efficient,agile,and quiet flight of flying animals.However,unlike lightweight FWAVs capable of vertical takeoff,relatively heavy FWAVs face challenges in self-takeoff,which refers to taking off without both external device and energy input.In this study,a cliff-drop method is implemented for an independent takeoff of a heavy FWAV,relying solely on gravity.In the takeoff process using the cliff-drop method,the FWAV moves on the ground to a cliff edge using a wheel-driving motor and then descends from the cliff to achieve the necessary speed for flight.To demonstrate the cliff-drop method,the KAIST Robotic Hawk(KRoHawk)with a mass of 740 g and a wingspan of 120 cm is developed.The takeoff tests demonstrate that the KRoHawk,significantly heavier than the vertical-takeoff capable FWAVs,can successfully take off using the gravity-assisted takeoff method.The scalability of cliff-drop method is analyzed through simulations.When drop constraints are absent,the wheel-driving motor mass fraction for cliff-drop method remains negligible even as the vehicle's weight increases.When drop constraints are set to 4 m,FWAVs heavier than KRoHawk,weighing up to 4.4 kg,can perform the cliff-drop takeoffs with a wheel-driving motor mass fraction of less than 8%.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC3702702)National Natural Science Foundation of China(Grant No.82103871).
文摘Clean air is fundamental to human health.Approximately 99%of the global population has been exposed to concentrations higher than the World Health Organization’s recommendations.Moreover,adverse health effects have been observed at much lower pollution levels than previously studied.China has experienced periods of severe air pollution over the past few decades.To improve air quality and safeguard public health,the government has implemented several progressively tightened policies.Emission control policies were first proposed in 2005.
文摘The Textile Technology Centre is the pride of Heberlein.State-of-the-art equipment and a team of top experts guarantee the highest standards of support for customers.Heberlein is the leading provider of air interlacing and air texturing jets for synthetic continuous filament yarns and its clients enjoy added value in the form of practical help and guidance on textile processes and economic issues,with a special focus on filament yarn applications.
文摘Shaoxing Shuifu Reeds is professional on producing all kinds of Air Jet Reeds and Flat Reeds,which has an annual output of 90,000 meters air-jet reeds,300,000,000 pcs of profile dents and 60,000 meters of Flat Reeds,Which has been honored with China Air Jet Profile Reeds Research Center by China Textile Machinery Association in 2015.In order to reach the demands of high quality fabric and industrial textile products,the yarn is developing to high count,multicolor,various fibers,and the fabric is developing to high count,high density,environment protection.So we have researched out high density,multicolor,multinozzle,double energy saving type profile reeds to let you choose.
基金supported by the National Natural Science Foundation of China(No.52276022).
文摘Direct air capture(DAC)is a negative carbon emission technology that faces challenges in scalability and practical deployment due to its exorbitant costs.Hou et al.(2017)integrated DAC technology with fertilization.A multi-bed desorption system driven by water provides a competitive and sustainable carbon source for indoor agriculture.
基金supported by the National Natural Science Foundation of Chinathe Civil Aviation Administration of China (U2333206).
文摘International freedom of the air(traffic rights)is a key resource for airlines to carry out international air transport business.An efficient and reasonable traffic right resource allocation within a country between airlines can affect the quality of a country’s participation in international air transport.In this paper,a multi-objective mixed-integer programming model for traffic rights resource allocation is developed to minimize passenger travel mileages and maximize the number of traffic rights resources allocated to hub airports and competitive carriers.A hybrid heuristic algorithm combining the genetic algorithm and the variable neighborhood search is devised to solve the model.The results show that the optimal allocation scheme aligns with the principle of fairness,indicating that the proposed model can play a certain guiding role in and provide an innovative perspective on traffic rights resource allocation in various countries.
文摘Carbon dioxide(CO_(2))is often monitored as a convenient yardstick for indoor air safety,yet its ability to stand in for pathogen-laden aerosols has never been settled.To probe the question,we reproduced an open-plan office at full scale(7.2m×5.2m×2.8m)and introduced a breathing plume that carried 4% CO_(2),together with a polydisperse aerosol spanning 0.5–10μm(1320 particles s^(−1)).Inlet air was supplied at 0.7,1.4,and 2.1 m s^(−1),and the resulting fields were simulated with a Realisable k–εRANS model coupled to Lagrangian particle tracking.Nine strategically placed probes provided validation;the calibrated solution deviated fromthe experiment by 58 ppm for CO_(2)(8.1%RMSE)and 0.008 m s^(−1)for velocity(15.7%RMSE).Despite this agreement,gas and particles behaved in sharply different ways.Room-averaged CO_(2)varied by<15%,whereas the aerosol mass rose to almost three-fold the background within slowmoving corner vortices.Sub-micron particles stayed aloft along streamlines,while those≥5μmpeeled away and settled on nearby surfaces.The divergence shows that neither the CO_(2)level nor themeanageof air,taken in isolation,delineates all high-exposure zones.We therefore recommend that ventilation design be informed by a composite diagnosis that couples gas data,size-resolved particle measurements,and rapid CFD appraisal.
基金supported by the National Natural Science Foundation of China(No.31900106)the East China University of Technology Practical Teaching Construction Project(No.DHSY-202261)。
文摘Airborne microorganisms(AM)have significant environmental and health implications.Extensive studies have been conducted to investigate the factors influencing the composition and diversity of AM.However,the knowledge of AM with anthropogenic activities has not reach a consensus.In this study,we took advantage of the dramatic decline of outdoor anthropogenic activities resulting from COVID-19 lockdown to reveal their associations.We collected airborne particulate matter before and during the lockdown period in two cities.The results showed that it was fungal diversity and communities but not bacteria obviously different between pre-lockdownand lockdown samples,suggesting that airborne fungiwere more susceptible to anthropogenic activities than bacteria.However,after the implementation of lockdown,the co-occurrence networks of both bacterial and fungal community became more complex,whichmight be due to the variation of microbial sources.Furthermore,Mantel test and correlation analysis showed that air pollutants also partly contributed to microbial alterations.Airborne fungal community was more affected by air pollutants than bacterial community.Notably,some human pathogens like Nigrospora and Arthrinium were negatively correlated with air pollutants.Overall,our study highlighted the more impacts of anthropogenic activities on airborne fungal community than bacterial community and advanced the understanding of associations between anthropogenic activities and AM.
基金supported by Capital health development research project(Grant No.2022-2G-4232)。
文摘Viruses, notably airborne viruses, are difficult to collect and detect because of the low concentrations of environmental microorganisms. Bacteriophages are frequently used in air experiments as suitable surrogates for human and animal viruses^([1]). Bacteriophages are non-pathogenic, so they are safe for laboratory workers and do not require specialized biological protection measures.Bacteriophages can be prepared at high titers using simple and low-cost methods.
基金supported in part by the National Natural Science Foundation of China(Nos.62167003,52302421)in part by the Diversified Investment Fund of Tianjin,China(No.23JCQNJC00210)。
文摘Airports around the world commonly face challenges in managing airport slot allocation.Effective management of limited slot resources by civil aviation authority often requires redistributing requested slots among airlines.The allocation process must operate within the prescribed capacity limits of the airport while adhering to established priorities and regulations.Additionally,ensuring market fairness is a key objective,as the value of airport slots plays a significant role in the adjustment process.This transforms the traditional time-shift-based problem into a complex multi-objective optimization problem.Addressing such complications is of significant importance to airlines,airports,and passengers alike.Due to the complexity of fairness metrics,traditional integer programming models encounter difficulties in finding effective solutions.This study proposes a neighborhood search strategy to tackle the single airport slot allocation,making it adaptable to both static and rolling capacity scenarios.Two Genetic Algorithms(GAs)are introduced,corresponding to time adjustment and sequence adjustment strategies,respectively.The GA based on the time adjustment strategy demonstrates high robustness,while the sequence adjustment strategy builds upon this GA to develop a simple heuristic algorithm that offers rapid convergence.Case studies conducted at seven airports in China confirm that all three algorithms yield high-quality adjustment solutions suitable for the majority of applications.Further,Pareto analysis reveals that these algorithms effectively balance the adjustment shifts and fairness metrics,demonstrating high practical value and broad applicability.
基金supported by the National Natural Science Foundation of China(Nos.U2033203,U1833126,61773203,61304190)。
文摘Air traffic flow management has been a major means for balancing air traffic demandand airport or airspace capacity to reduce congestion and flight delays.However,unpredictable fac-tors,such as weather and equipment malfunctions,can cause dynamic changes in airport and sectorcapacity,resulting in significant alterations to optimized flight schedules and the calculated pre-departure slots.Therefore,taking into account capacity uncertainties is essential to create a moreresilient flight schedule.This paper addresses the flight pre-departure sequencing issue and intro-duces a capacity uncertainty model for optimizing flight schedule at the airport network level.The goal of the model is to reduce the total cost of flight delays while increasing the robustnessof the optimized schedule.A chance-constrained model is developed to address the capacity uncer-tainty of airports and sectors,and the significance of airports and sectors in the airport network isconsidered when setting the violation probability.The performance of the model is evaluated usingreal flight data by comparing them with the results of the deterministic model.The development ofthe model based on the characteristics of this special optimization mechanism can significantlyenhance its performance in addressing the pre-departure flight scheduling problem at the airportnetwork level.
基金supported by National Natural Science Foundation of China(22279018)National Natural Science Foundation of China(22005055)Natural Science Foundation of Fujian Province(2022J01085).
文摘Solid oxide cells(SOCs)are emerging devices for efficient energy storage and conversion.However,during SOC operation,gaseous chromium(Cr)species released from Fe-Cr alloy interconnect can lead to Cr deposition and poisoning of air electrodes,causing substantial degradation in electrochemical performance and compromising the longterm stability of SOCs.This mini-review examines the mechanism of Cr deposition and poisoning in air electrodes under both fuel-cell and electrolysis modes.Furthermore,emphasis is placed on the recent advancements in strategies to mitigate Cr poisoning,offering insights into the rational design and development of active and Cr-tolerant air electrodes for SOCs.
基金supported by Fundamental Research Funds for the Central Universities(2023KYJD1008)the Science Research Projects of the Anhui Higher Education Institutions of China(2022AH051582).
文摘Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage poses challenges for the performance and stability of air electrodes.In this work,a novel high-entropy perovskite oxide La_(0.2)Pr_(0.2)Gd_(0.2)Sm_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF)is proposed and investigated as an air electrode in RSOC.The electrochemical behavior of HE-LSCF was studied as an air electrode in both fuel cell and electrolysis modes.The polarization impedance(Rp)of the HE-LSCF electrode is only 0.25Ω·cm^(2) at 800℃ in an air atmosphere.Notably,at an electrolytic voltage of 2 V and a temperature of 800℃,the current density reaches up to 1.68 A/cm^(2).The HE-LSCF air electrode exhibited excellent reversibility and stability,and its electrochemical performance remains stable after 100 h of reversible operation.With these advantages,HE-LSCF is shown to be an excellent air electrode for RSOC.
基金supported by the National Natural Science Foundation of China(Grant No.92044303)。
文摘Air pollution in China covers a large area with complex sources and formation mechanisms,making it a unique place to conduct air pollution and atmospheric chemistry research.The National Natural Science Foundation of China’s Major Research Plan entitled“Fundamental Researches on the Formation and Response Mechanism of the Air Pollution Complex in China”(or the Plan)has funded 76 research projects to explore the causes of air pollution in China,and the key processes of air pollution in atmospheric physics and atmospheric chemistry.In order to summarize the abundant data from the Plan and exhibit the long-term impacts domestically and internationally,an integration project is responsible for collecting the various types of data generated by the 76 projects of the Plan.This project has classified and integrated these data,forming eight categories containing 258 datasets and 15 technical reports in total.The integration project has led to the successful establishment of the China Air Pollution Data Center(CAPDC)platform,providing storage,retrieval,and download services for the eight categories.This platform has distinct features including data visualization,related project information querying,and bilingual services in both English and Chinese,which allows for rapid searching and downloading of data and provides a solid foundation of data and support for future related research.Air pollution control in China,especially in the past decade,is undeniably a global exemplar,and this data center is the first in China to focus on research into the country’s air pollution complex.
