In order to ease congestion and ground delays in major hub airports, an aircraft taxiing scheduling optimization model is proposed with schedule time as the object function. In the new model, the idea of a classical j...In order to ease congestion and ground delays in major hub airports, an aircraft taxiing scheduling optimization model is proposed with schedule time as the object function. In the new model, the idea of a classical job shop-schedule problem is adopted and three types of special aircraft-taxi conflicts are considered in the constraints. To solve such nondeterministic polynomial time-complex problems, the immune clonal selection algorithm（ICSA） is introduced. The simulation results in a congested hour of Beijing Capital International Airport show that, compared with the first-come-first-served（FCFS） strategy, the optimization-planning strategy reduces the total scheduling time by 13.6 min and the taxiing time per aircraft by 45.3 s, which improves the capacity of the runway and the efficiency of airport operations.展开更多
The objective of this study is to improve the methods of determining unimpeded（nominal） taxiing time,which is the reference time used for estimating taxiing delay,a widely accepted performance indicator of airport s...The objective of this study is to improve the methods of determining unimpeded（nominal） taxiing time,which is the reference time used for estimating taxiing delay,a widely accepted performance indicator of airport surface movement.After reviewing existing methods used widely by different air navigation service providers（ANSP）,new methods relying on computer software and statistical tools,and econometrics regression models are proposed.Regression models are highly recommended because they require less detailed data and can serve the needs of general performance analysis of airport surface operations.The proposed econometrics model outperforms existing ones by introducing more explanatory variables,especially taking aircraft passing and over-passing into the considering of queue length calculation and including runway configuration,ground delay program,and weather factors.The length of the aircraft queue in the taxiway system and the interaction between queues are major contributors to long taxi-out times.The proposed method provides a consistent and more accurate method of calculating taxiing delay and it can be used for ATM-related performance analysis and international comparison.展开更多
Ground taxiing is the key process of take-off and landing for a tricycle-undercarriage unmanned aerial vehicle( UAV). Nonlinear model of a sample UAV is established based on stiffness and damping model of landing gear...Ground taxiing is the key process of take-off and landing for a tricycle-undercarriage unmanned aerial vehicle( UAV). Nonlinear model of a sample UAV is established based on stiffness and damping model of landing gears and tires taken into account. Then lateral nonlinear model is linearized and state space equations are deduced by using nose wheel and ruder as inputs and lateral states as outputs. Adaptive internal model control( AIMC) is proposed and applied to lateral control based on decoupled and linearized dynamic model during ground taxiing process. Different control strategies are analyzed and compared by simulations,and then a combined control strategy of nose wheel steering with holding and rudder control is given. Hardware in loop simulations( HILS) proves the validity of the controller designed.展开更多
The issue of green aircraft taxiing under various taxi scenarios is studied to improve the efficiency of aircraft surface operations and reduce environmental pollution around the airport from aircraft emissions.A gree...The issue of green aircraft taxiing under various taxi scenarios is studied to improve the efficiency of aircraft surface operations and reduce environmental pollution around the airport from aircraft emissions.A green aircraft taxi programming model based on multi-scenario joint optimization is built according to airport surface network topology modeling by analyzing the characteristics of aircraft operations under three different taxiing scenarios:all-engine taxi,single-engine taxi,and electronic taxi.A genetic algorithm is also used in the model to minimize fuel consumption and pollutant emissions.The Shanghai Pudong International Airport is selected as a typical example to conduct a verification analysis.Compared with actual operational data,the amount of aircraft fuel consumption and gas emissions after optimization are reduced significantly through applying the model.Under an electronic taxiing scenario,fuel consumption can be lowered by 45.3%,and hydrocarbon(HC)and carbon dioxide(CO)emissions are decreased by 80%.The results show that a green aircraft taxiing strategy that integrates taxiway optimization and electronic taxiing can effectively improve the efficiency of airport operations and reduce aircraft pollution levels in an airport′s peripheral environment.展开更多
Most of the traditional taxi path planning studies assume that the aircraft is in uniform speed,and the optimization goal is the shortest taxi time.Although it is easy to solve,it does not consider the changes in the ...Most of the traditional taxi path planning studies assume that the aircraft is in uniform speed,and the optimization goal is the shortest taxi time.Although it is easy to solve,it does not consider the changes in the speed profile of the aircraft when turning,and the shortest taxi time does not necessarily bring the best taxi fuel consumption.In this paper,the number of turns is considered,and the improved A*algorithm is used to obtain the P static paths with the shortest sum of the straight-line distance and the turning distance of the aircraft as the feasible taxi paths.By balancing taxi time and fuel consumption,a set of Pareto optimal speed profiles are generated for each preselected path to predict the 4-D trajectory of the aircraft.Based on the 4-D trajectory prediction results,the conflict by the occupied time window in the taxiing area is detected.For the conflict aircraft,based on the priority comparison,the waiting or changing path is selected to solve the taxiing conflict.Finally,the conflict free aircraft taxiing path is generated and the area occupation time window on the path is updated.The experimental results show that the total taxi distance and turn time of the aircraft are reduced,and the fuel consumption is reduced.The proposed method has high practical application value and is expected to be applied in real-time air traffic control decision-making in the future.展开更多
The aviation industry has thrived in recent years,with a significant increase in passenger numbers,leading to the development of larger aircraft fleets and the expansion of airport infrastructure.In 2019,more than 4.5...The aviation industry has thrived in recent years,with a significant increase in passenger numbers,leading to the development of larger aircraft fleets and the expansion of airport infrastructure.In 2019,more than 4.5 billion passengers traveled by airplane,which represents an 80%increase compared to 2009.As a consequence,this growth has also resulted in longer taxiing times for aircraft,increasing fuel consumption and operational costs.The industry’s CO_(2) emissions have quadrupled since the 1960s,with over 1 billion tons released in 2019,contributing to global warming.Given that the improvements being made to current propulsion systems and the production of over 600 million liters of SAF(Sustainable Aviation Fuel)in 2023 do not seem sufficient to meet the ambitious goals set by regulators and operators,the logical solution would be to develop a system capable of moving the aircraft on the ground using alternative,cleaner,and cheaper energies,such as electric power.This paper explores the latest advancements in electric propulsion systems,specifically focusing on external and onboard systems.After the state of the art is established,this paper will cover a case study and propose a new alternative for an onboard system called ETS-Electric Taxiing System.The ETS is a 100%electric system for ground handling operations designed to use only the kinetic energy stored in a battery pack,which is recovered during aircraft landing and braking events.Although there are some studies on this topic,the author considers this paper to be more comprehensive as the results computed here take into account 96 variables,60 simulations,several flight plans,and real-world data.The case study focuses on the implementation and dimensioning of the ETS,considering electric motor power and torque,and battery capacity for the Embraer Phenom 300.A brief economic and environmental analysis was also conducted,considering the operation of NetJets Europe,the world’s leading and largest private jet company.展开更多
Sustainable development has become a critical global priority,and green transportation solutions,such as electric taxis,play a vital role in achieving this goal.This study examines the factors influencing students’in...Sustainable development has become a critical global priority,and green transportation solutions,such as electric taxis,play a vital role in achieving this goal.This study examines the factors influencing students’intentions to adopt electric taxi services in Hanoi,Vietnam,as a step toward sustainable urban mobility.We surveyed 573 students and ana-lyzed key determinants using reliability tests,exploratory factor analysis(EFA),and linear regression.The results indi-cate that four factors significantly influence adoption intentions:Perceived Usefulness and Sustainability,Price,Brand Awareness,and Service Quality.Among these,Perceived Usefulness and Sustainability had the strongest positive im-pact,while Service Quality exerted the weakest influence.Notably,Habit and Ease of Use&Transaction Convenience were found to be statistically insignificant in the final model.These findings provide practical implications for business-es and policymakers aiming to use electric taxi adoption.To enhance appeal,stakeholders should emphasize environ-mental benefits,competitive pricing,and brand recognition while improving service reliability.By addressing these fac-tors,electric taxi services can accelerate the transition to sustainable transportation,aligning with global climate goals and transforming urban mobility.This study offers actionable insights for encouraging greener travel behaviors among students,a key demographic for long-term sustainability impact.展开更多
1 There was a taxi driver who was angry and wanted to finish his shift as soon as possible.When he arrived to pick up his last passenger of the day,he honked the horn(按喇叭),but no one came out of the apartment.Minut...1 There was a taxi driver who was angry and wanted to finish his shift as soon as possible.When he arrived to pick up his last passenger of the day,he honked the horn(按喇叭),but no one came out of the apartment.Minutes later,he honked again,but still there was no reaction.展开更多
When youre a taxi driver,you never know who youll end up picking up—it might even be a long-lost friend from over 20 years ago!51-year-old Texas resident Danny Blanton was captured in the most funny moment by the das...When youre a taxi driver,you never know who youll end up picking up—it might even be a long-lost friend from over 20 years ago!51-year-old Texas resident Danny Blanton was captured in the most funny moment by the dashboard camera when he realized his passenger was not a stranger.This man was a dear friend from his past!展开更多
Background:Atopic dermatitis is a chronic inflammatory skin disorder characterized by recurrent eczema-like rashes and severe itching.Taxi San is an external herbal formulation with the effects of clearing heat,drying...Background:Atopic dermatitis is a chronic inflammatory skin disorder characterized by recurrent eczema-like rashes and severe itching.Taxi San is an external herbal formulation with the effects of clearing heat,drying dampness,detoxifying,and relieving itching,making it suitable for treating acute and subacute dermatitis or eczema.Objectives:To evaluate the clinical efficacy of topical Taxi San in treating atopic dermatitis patients with dampness-heat syndrome and its inhibitory effect against Staphylococcus aureus(S.aureus)colonization.Methods:50 patients with atopic dermatitis were enrolled from the Dermatology Department of Shaanxi Provincial Hospital of Traditional Chinese Medicine,with bilateral symmetrical lesions selected as target sites.The control-side lesions were treated with boric acid solution wet compresses,while the treatment-side lesions received Taxi San solution wet compresses,both administered twice daily for 14 d.Clinical efficacy was evaluated using the Scoring Atopic Dermatitis(SCORAD),Investigator Global Assessment(IGA),Dermatology Life Quality Index/Children’s Dermatology Life Quality Index(DLQI/CDLQI),adverse events(AEs)and S.aureus colonization density,which were compared between the groups.The antibacterial efficacy of Taxi San was further investigated through in vitro antibacterial tests.Results:After 14 d of treatment with Taxi San,erythema and pimples were reduced on the treated sides.Additionally,the SCORAD,IGA,and DLQI/CDLQI scores showed significant decreases(P<0.05).S.aureus colonization on the treated sides declined markedly from 78%to 4.76%.Compared to the control sides,the reduction in S.aureus colonization following 14 d of Taxi San treatment was statistically significant(P<0.05).Furthermore,in vitro antibacterial assays demonstrated that the minimum inhibitory concentration of Taxi San against the seven tested S.aureus strains was 0.125 g/mL.Conclusions:Taxi San effectively reduces S.aureus colonization and ameliorates clinical symptoms in atopic dermatitis patients with dampness-heat syndrome,demonstrating high therapeutic potential and safety.展开更多
In order to determine the regulations of the development of taxi supply under entry regulations in Chinese cities, an improved neural network model is applied to find the particular years when the government artificia...In order to determine the regulations of the development of taxi supply under entry regulations in Chinese cities, an improved neural network model is applied to find the particular years when the government artificially puts new taxis into the market, and then extract the political influence from the taxi supply. The model is also utilized to study the relationships between the adjusted taxi supply and non-policy factors. A case study of Nanjing city is conducted. The results show that 2001 and 2007 are the particular years that the Nanjing government artificially put new taxis into its taxi market, which is in accordance with the five-year plan of China and the local development plans. The results also show that the improved neural network model has a good performance in expositing the evolution of adjusted taxi supply related to non-policy factors.展开更多
Abstract This study investigates an instability that was observed during highspeed taxi tests of an experimental flyingwing aircraft. In order to resolve the reason of instability and probable solution of it, the inst...Abstract This study investigates an instability that was observed during highspeed taxi tests of an experimental flyingwing aircraft. In order to resolve the reason of instability and probable solution of it, the instability was reproduced in simulations. An analysis revealed the unique stability char acteristics of this aircraft. This aircraft has a rigid connection between the nose wheel steering mech anism and an electric servo, which is different from aircraft with a conventional tricycle landing gear system. The analysis based on simulation results suggests that there are two reasons for the insta bility. The first reason is a reversal of the lateral velocity of the nose wheel. The second reason is that the moment about the center of gravity created by the lateral friction force from the nose wheel is larger than that from lhe lateral friction force from the main wheels. These problems were corrected by changing the ground pitch angle. Simulations show that reducing the ground pitch angle can eliminate the instability in highspeed taxi.展开更多
The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with ...The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with traditional probability techniques based on the linear chain of events. However, it could not comprehensively analyze system safety problems, especially in operating environment, interaction of subsystems, and human factors. Thus,we consider system safety as a control problem based on the system-theoretic accident model, the processes(STAMP) model and the system theoretic process analysis(STPA) technique to compensate the deficiency of traditional techniques. Meanwhile,system safety simulation is considered as system control simulation, and Monte Carlo methods are used which consider the range of uncertain parameters and operation deviation to quantitatively study system safety influence factors in control simulation. Firstly,we construct the STAMP model and STPA feedback control loop of the wheel brake system based on the system functional requirement. Then four unsafe control actions are identified, and causes of them are analyzed. Finally, we construct the Monte Carlo simulation model to analyze different scenarios under disturbance. The results provide a basis for choosing corresponding process model variables in constructing the context table and show that appropriate brake strategies could prevent hazards in aircraft landing taxiing.展开更多
Aircraft ground movement plays a key role in improving airport efficiency,as it acts as a link to all other ground operations.Finding novel approaches to coordinate the movements of a fleet of aircraft at an airport i...Aircraft ground movement plays a key role in improving airport efficiency,as it acts as a link to all other ground operations.Finding novel approaches to coordinate the movements of a fleet of aircraft at an airport in order to improve system resilience to disruptions with increasing autonomy is at the center of many key studies for airport airside operations.Moreover,autonomous taxiing is envisioned as a key component in future digitalized airports.However,state-of-the-art routing and scheduling algorithms for airport ground movements do not consider high-fidelity aircraft models at both the proactive and reactive planning phases.The majority of such algorithms do not actively seek to optimize fuel efficiency and reduce harmful greenhouse gas emissions.This paper proposes a new approach for generating efficient four-dimensional trajectories(4DTs)on the basis of a high-fidelity aircraft model and gainscheduling control strategy.Working in conjunction with a routing and scheduling algorithm that determines the taxi route,waypoints,and time deadlines,the proposed approach generates fuel-efficient 4DTs in real time,while respecting operational constraints.The proposed approach can be used in two contexts:①as a reactive decision support tool to generate new trajectories that can resolve unprecedented events;and②as an autopilot system for both partial and fully autonomous taxiing.The proposed methodology is realistic and simple to implement.Moreover,simulation studies show that the proposed approach is capable of providing an up to 11%reduction in the fuel consumed during the taxiing of a large Boeing 747-100 jumbo jet.展开更多
Endophytic fungi are widely found in almost all kinds of plants. Many endophytic fungi can produce some physio-logical active compounds, which are same to or analog to those isolated from their hosts. Producing physio...Endophytic fungi are widely found in almost all kinds of plants. Many endophytic fungi can produce some physio-logical active compounds, which are same to or analog to those isolated from their hosts. Producing physiological active com-pounds through microbial fermentation can give a new way to resolve resource limitation and to find out alternative source. Through the methods of organic solvent extraction, thin layer chromatography (TLC) and column chromatography, compound I was isolated, purified from the liquid fermentation metabolites of the taxoids-produced endophytic fungi (Alternaria. alternata var. taxi 1011 Y. Xiang et LU An-guo) that was screened from the bark of Taxus. cuspidata Sieb.et Zucc.. Compound I was identified as one kind of taxoids type III, based on the analyzing results by using the methods of ultraviolet spectroscopy (UV), infrared spectroscopy (IR), mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR). This study provides a com-pleted method for separation and purification of the endophytic fungi as well as structure identification of its fermentation me-tabolite展开更多
基金Supported by the Basic Scientific Research Projects of the Central University of China(ZXH2010D010)the National Natural Science Foundation of China(60979021/F01)~~
文摘In order to ease congestion and ground delays in major hub airports, an aircraft taxiing scheduling optimization model is proposed with schedule time as the object function. In the new model, the idea of a classical job shop-schedule problem is adopted and three types of special aircraft-taxi conflicts are considered in the constraints. To solve such nondeterministic polynomial time-complex problems, the immune clonal selection algorithm（ICSA） is introduced. The simulation results in a congested hour of Beijing Capital International Airport show that, compared with the first-come-first-served（FCFS） strategy, the optimization-planning strategy reduces the total scheduling time by 13.6 min and the taxiing time per aircraft by 45.3 s, which improves the capacity of the runway and the efficiency of airport operations.
基金supported by FAA ATO-G under contract DTFAWA-09-P-00245
文摘The objective of this study is to improve the methods of determining unimpeded（nominal） taxiing time,which is the reference time used for estimating taxiing delay,a widely accepted performance indicator of airport surface movement.After reviewing existing methods used widely by different air navigation service providers（ANSP）,new methods relying on computer software and statistical tools,and econometrics regression models are proposed.Regression models are highly recommended because they require less detailed data and can serve the needs of general performance analysis of airport surface operations.The proposed econometrics model outperforms existing ones by introducing more explanatory variables,especially taking aircraft passing and over-passing into the considering of queue length calculation and including runway configuration,ground delay program,and weather factors.The length of the aircraft queue in the taxiway system and the interaction between queues are major contributors to long taxi-out times.The proposed method provides a consistent and more accurate method of calculating taxiing delay and it can be used for ATM-related performance analysis and international comparison.
基金Sponsored by the Knowledge Innovation Project of Chinese Academy of Sciences(Grant No.YYJ-1122)
文摘Ground taxiing is the key process of take-off and landing for a tricycle-undercarriage unmanned aerial vehicle( UAV). Nonlinear model of a sample UAV is established based on stiffness and damping model of landing gears and tires taken into account. Then lateral nonlinear model is linearized and state space equations are deduced by using nose wheel and ruder as inputs and lateral states as outputs. Adaptive internal model control( AIMC) is proposed and applied to lateral control based on decoupled and linearized dynamic model during ground taxiing process. Different control strategies are analyzed and compared by simulations,and then a combined control strategy of nose wheel steering with holding and rudder control is given. Hardware in loop simulations( HILS) proves the validity of the controller designed.
文摘The issue of green aircraft taxiing under various taxi scenarios is studied to improve the efficiency of aircraft surface operations and reduce environmental pollution around the airport from aircraft emissions.A green aircraft taxi programming model based on multi-scenario joint optimization is built according to airport surface network topology modeling by analyzing the characteristics of aircraft operations under three different taxiing scenarios:all-engine taxi,single-engine taxi,and electronic taxi.A genetic algorithm is also used in the model to minimize fuel consumption and pollutant emissions.The Shanghai Pudong International Airport is selected as a typical example to conduct a verification analysis.Compared with actual operational data,the amount of aircraft fuel consumption and gas emissions after optimization are reduced significantly through applying the model.Under an electronic taxiing scenario,fuel consumption can be lowered by 45.3%,and hydrocarbon(HC)and carbon dioxide(CO)emissions are decreased by 80%.The results show that a green aircraft taxiing strategy that integrates taxiway optimization and electronic taxiing can effectively improve the efficiency of airport operations and reduce aircraft pollution levels in an airport′s peripheral environment.
基金supported by the National Key R&D Project(No.2020YFB1600101)National Natural Science Foundations of China(Nos.U1833103,71801215)Civil Aviation Flight Wide Area Surveillance and Safety Control Technology Key Laboratory Open Fund(No.202008)。
文摘Most of the traditional taxi path planning studies assume that the aircraft is in uniform speed,and the optimization goal is the shortest taxi time.Although it is easy to solve,it does not consider the changes in the speed profile of the aircraft when turning,and the shortest taxi time does not necessarily bring the best taxi fuel consumption.In this paper,the number of turns is considered,and the improved A*algorithm is used to obtain the P static paths with the shortest sum of the straight-line distance and the turning distance of the aircraft as the feasible taxi paths.By balancing taxi time and fuel consumption,a set of Pareto optimal speed profiles are generated for each preselected path to predict the 4-D trajectory of the aircraft.Based on the 4-D trajectory prediction results,the conflict by the occupied time window in the taxiing area is detected.For the conflict aircraft,based on the priority comparison,the waiting or changing path is selected to solve the taxiing conflict.Finally,the conflict free aircraft taxiing path is generated and the area occupation time window on the path is updated.The experimental results show that the total taxi distance and turn time of the aircraft are reduced,and the fuel consumption is reduced.The proposed method has high practical application value and is expected to be applied in real-time air traffic control decision-making in the future.
文摘The aviation industry has thrived in recent years,with a significant increase in passenger numbers,leading to the development of larger aircraft fleets and the expansion of airport infrastructure.In 2019,more than 4.5 billion passengers traveled by airplane,which represents an 80%increase compared to 2009.As a consequence,this growth has also resulted in longer taxiing times for aircraft,increasing fuel consumption and operational costs.The industry’s CO_(2) emissions have quadrupled since the 1960s,with over 1 billion tons released in 2019,contributing to global warming.Given that the improvements being made to current propulsion systems and the production of over 600 million liters of SAF(Sustainable Aviation Fuel)in 2023 do not seem sufficient to meet the ambitious goals set by regulators and operators,the logical solution would be to develop a system capable of moving the aircraft on the ground using alternative,cleaner,and cheaper energies,such as electric power.This paper explores the latest advancements in electric propulsion systems,specifically focusing on external and onboard systems.After the state of the art is established,this paper will cover a case study and propose a new alternative for an onboard system called ETS-Electric Taxiing System.The ETS is a 100%electric system for ground handling operations designed to use only the kinetic energy stored in a battery pack,which is recovered during aircraft landing and braking events.Although there are some studies on this topic,the author considers this paper to be more comprehensive as the results computed here take into account 96 variables,60 simulations,several flight plans,and real-world data.The case study focuses on the implementation and dimensioning of the ETS,considering electric motor power and torque,and battery capacity for the Embraer Phenom 300.A brief economic and environmental analysis was also conducted,considering the operation of NetJets Europe,the world’s leading and largest private jet company.
文摘Sustainable development has become a critical global priority,and green transportation solutions,such as electric taxis,play a vital role in achieving this goal.This study examines the factors influencing students’intentions to adopt electric taxi services in Hanoi,Vietnam,as a step toward sustainable urban mobility.We surveyed 573 students and ana-lyzed key determinants using reliability tests,exploratory factor analysis(EFA),and linear regression.The results indi-cate that four factors significantly influence adoption intentions:Perceived Usefulness and Sustainability,Price,Brand Awareness,and Service Quality.Among these,Perceived Usefulness and Sustainability had the strongest positive im-pact,while Service Quality exerted the weakest influence.Notably,Habit and Ease of Use&Transaction Convenience were found to be statistically insignificant in the final model.These findings provide practical implications for business-es and policymakers aiming to use electric taxi adoption.To enhance appeal,stakeholders should emphasize environ-mental benefits,competitive pricing,and brand recognition while improving service reliability.By addressing these fac-tors,electric taxi services can accelerate the transition to sustainable transportation,aligning with global climate goals and transforming urban mobility.This study offers actionable insights for encouraging greener travel behaviors among students,a key demographic for long-term sustainability impact.
文摘1 There was a taxi driver who was angry and wanted to finish his shift as soon as possible.When he arrived to pick up his last passenger of the day,he honked the horn(按喇叭),but no one came out of the apartment.Minutes later,he honked again,but still there was no reaction.
文摘When youre a taxi driver,you never know who youll end up picking up—it might even be a long-lost friend from over 20 years ago!51-year-old Texas resident Danny Blanton was captured in the most funny moment by the dashboard camera when he realized his passenger was not a stranger.This man was a dear friend from his past!
基金supported by the Shaanxi Provincial Research and Innovation Team for Atopic Dermatitis of Traditional Chinese Medicine(No.TZKN-CXTD-02)the Key Industry Innovation Chain Project of Shaanxi Province(No.2021ZDLSF04-12).
文摘Background:Atopic dermatitis is a chronic inflammatory skin disorder characterized by recurrent eczema-like rashes and severe itching.Taxi San is an external herbal formulation with the effects of clearing heat,drying dampness,detoxifying,and relieving itching,making it suitable for treating acute and subacute dermatitis or eczema.Objectives:To evaluate the clinical efficacy of topical Taxi San in treating atopic dermatitis patients with dampness-heat syndrome and its inhibitory effect against Staphylococcus aureus(S.aureus)colonization.Methods:50 patients with atopic dermatitis were enrolled from the Dermatology Department of Shaanxi Provincial Hospital of Traditional Chinese Medicine,with bilateral symmetrical lesions selected as target sites.The control-side lesions were treated with boric acid solution wet compresses,while the treatment-side lesions received Taxi San solution wet compresses,both administered twice daily for 14 d.Clinical efficacy was evaluated using the Scoring Atopic Dermatitis(SCORAD),Investigator Global Assessment(IGA),Dermatology Life Quality Index/Children’s Dermatology Life Quality Index(DLQI/CDLQI),adverse events(AEs)and S.aureus colonization density,which were compared between the groups.The antibacterial efficacy of Taxi San was further investigated through in vitro antibacterial tests.Results:After 14 d of treatment with Taxi San,erythema and pimples were reduced on the treated sides.Additionally,the SCORAD,IGA,and DLQI/CDLQI scores showed significant decreases(P<0.05).S.aureus colonization on the treated sides declined markedly from 78%to 4.76%.Compared to the control sides,the reduction in S.aureus colonization following 14 d of Taxi San treatment was statistically significant(P<0.05).Furthermore,in vitro antibacterial assays demonstrated that the minimum inhibitory concentration of Taxi San against the seven tested S.aureus strains was 0.125 g/mL.Conclusions:Taxi San effectively reduces S.aureus colonization and ameliorates clinical symptoms in atopic dermatitis patients with dampness-heat syndrome,demonstrating high therapeutic potential and safety.
基金The National Basic Research Program of China(973 Program)(No.2012CB725400)
文摘In order to determine the regulations of the development of taxi supply under entry regulations in Chinese cities, an improved neural network model is applied to find the particular years when the government artificially puts new taxis into the market, and then extract the political influence from the taxi supply. The model is also utilized to study the relationships between the adjusted taxi supply and non-policy factors. A case study of Nanjing city is conducted. The results show that 2001 and 2007 are the particular years that the Nanjing government artificially put new taxis into its taxi market, which is in accordance with the five-year plan of China and the local development plans. The results also show that the improved neural network model has a good performance in expositing the evolution of adjusted taxi supply related to non-policy factors.
文摘Abstract This study investigates an instability that was observed during highspeed taxi tests of an experimental flyingwing aircraft. In order to resolve the reason of instability and probable solution of it, the instability was reproduced in simulations. An analysis revealed the unique stability char acteristics of this aircraft. This aircraft has a rigid connection between the nose wheel steering mech anism and an electric servo, which is different from aircraft with a conventional tricycle landing gear system. The analysis based on simulation results suggests that there are two reasons for the insta bility. The first reason is a reversal of the lateral velocity of the nose wheel. The second reason is that the moment about the center of gravity created by the lateral friction force from the nose wheel is larger than that from lhe lateral friction force from the main wheels. These problems were corrected by changing the ground pitch angle. Simulations show that reducing the ground pitch angle can eliminate the instability in highspeed taxi.
文摘The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with traditional probability techniques based on the linear chain of events. However, it could not comprehensively analyze system safety problems, especially in operating environment, interaction of subsystems, and human factors. Thus,we consider system safety as a control problem based on the system-theoretic accident model, the processes(STAMP) model and the system theoretic process analysis(STPA) technique to compensate the deficiency of traditional techniques. Meanwhile,system safety simulation is considered as system control simulation, and Monte Carlo methods are used which consider the range of uncertain parameters and operation deviation to quantitatively study system safety influence factors in control simulation. Firstly,we construct the STAMP model and STPA feedback control loop of the wheel brake system based on the system functional requirement. Then four unsafe control actions are identified, and causes of them are analyzed. Finally, we construct the Monte Carlo simulation model to analyze different scenarios under disturbance. The results provide a basis for choosing corresponding process model variables in constructing the context table and show that appropriate brake strategies could prevent hazards in aircraft landing taxiing.
基金This work was funded by the UK Engineering and Physical Sciences Research Council(EP/N029496/1,EP/N029496/2,EP/N029356/1,EP/N029577/1,and EP/N029577/2).
文摘Aircraft ground movement plays a key role in improving airport efficiency,as it acts as a link to all other ground operations.Finding novel approaches to coordinate the movements of a fleet of aircraft at an airport in order to improve system resilience to disruptions with increasing autonomy is at the center of many key studies for airport airside operations.Moreover,autonomous taxiing is envisioned as a key component in future digitalized airports.However,state-of-the-art routing and scheduling algorithms for airport ground movements do not consider high-fidelity aircraft models at both the proactive and reactive planning phases.The majority of such algorithms do not actively seek to optimize fuel efficiency and reduce harmful greenhouse gas emissions.This paper proposes a new approach for generating efficient four-dimensional trajectories(4DTs)on the basis of a high-fidelity aircraft model and gainscheduling control strategy.Working in conjunction with a routing and scheduling algorithm that determines the taxi route,waypoints,and time deadlines,the proposed approach generates fuel-efficient 4DTs in real time,while respecting operational constraints.The proposed approach can be used in two contexts:①as a reactive decision support tool to generate new trajectories that can resolve unprecedented events;and②as an autopilot system for both partial and fully autonomous taxiing.The proposed methodology is realistic and simple to implement.Moreover,simulation studies show that the proposed approach is capable of providing an up to 11%reduction in the fuel consumed during the taxiing of a large Boeing 747-100 jumbo jet.
文摘Endophytic fungi are widely found in almost all kinds of plants. Many endophytic fungi can produce some physio-logical active compounds, which are same to or analog to those isolated from their hosts. Producing physiological active com-pounds through microbial fermentation can give a new way to resolve resource limitation and to find out alternative source. Through the methods of organic solvent extraction, thin layer chromatography (TLC) and column chromatography, compound I was isolated, purified from the liquid fermentation metabolites of the taxoids-produced endophytic fungi (Alternaria. alternata var. taxi 1011 Y. Xiang et LU An-guo) that was screened from the bark of Taxus. cuspidata Sieb.et Zucc.. Compound I was identified as one kind of taxoids type III, based on the analyzing results by using the methods of ultraviolet spectroscopy (UV), infrared spectroscopy (IR), mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR). This study provides a com-pleted method for separation and purification of the endophytic fungi as well as structure identification of its fermentation me-tabolite
