The Contribution of United States Aircraft Reconnaissance Data to the China Meteorological Administration Tropical Cyclone Intensity Data:An Evaluation of Homogeneity

This paper investigates the homogeneity of United States aircraft reconnaissance data and the impact of these data on the homogeneity of the tropical cyclone(TC)best track data for the seasons 1949-1987 generated by the China Meteorological Administration(CMA).The evaluation of the reconnaissance data shows that the minimum central sea level pressure(MCP)data are relatively homogeneous,whereas the maximum sustained wind(MSW)data show both overestimations and spurious abrupt changes.Statistical comparisons suggest that both the reconnaissance MCP and MSW were well incorporated into the CMA TC best track dataset.Although no spurious abrupt changes were evident in the reconnaissance-related best track MCP data,two spurious changepoints were identified in the remainder of the best-track MCP data.Furthermore,the influence of the reconnaissance MSWs seems to extend to the best track MSWs unrelated to reconnaissance,which might reflect the optimistic confidence in making higher estimates due to the overestimated extreme wind“observations”.In addition,the overestimation of either the reconnaissance MSWs or the best track MSWs was greater during the early decades compared to later decades,which reflects the important influence of reconnaissance data on the CMA TC best track dataset.The wind-pressure relationship(WPR)used in the CMA TC best track dataset is also evaluated and is found to overestimate the MSW,which may lead to inhomogeneity within the dataset between the aircraft reconnaissance era and the satellite era.

Analysis and Research on Aerodynamic Characteristics of Quad Tilt Rotor Aircraft

For the quad tilt rotor aircraft, a computational fluid dynamics method based on multiple reference frames (MRF) was used to analyze the influence of aerodynamic layout parameters on the aerodynamic characteristics of the quad tilt rotor aircraft. Firstly, a numerical simulation method for the interference flow field of the quad tilt rotor aircraft is established. Based on this method, the aerodynamic characteristics of isolated rotors, rotor combinations at different lateral positions on the wing, and rotor rotation directions under different inflow velocities were calculated and analyzed, in order to grasp their aerodynamic interference laws and provide reference for the design and control theory research of such aircraft.

Assessment of Meteorological Threats to the Coordinated Search and Rescue of Unmanned/Manned Aircraft

The architecture and working principle of coordinated search and rescue system of unmanned/manned aircraft,which is composed of manned/unmanned aircraft and manned aircraft,were first introduced,and they can cooperate with each other to complete a search and rescue task.Secondly,a threat assessment method based on meteorological data was proposed,and potential meteorological threats,such as storms and rainfall,can be predicted by collecting and analyzing meteorological data.Finally,an experiment was carried out to evaluate the performance of the proposed method in different scenarios.The experimental results show that the coordinated search and rescue system of unmanned/manned aircraft can be used to effectively assess meteorological threats and provide accurate search and rescue guidance.

基于RF-MEA-Elman的埋地腐蚀管道剩余寿命精度预测研究

针对传统腐蚀管道预测方法适应性差及精度低等问题,提出一种随机森林算法(RF)、思维进化法(MEA)及Elman相结合的模型(即RF-MEA-Elman模型)。首先采用RF对管道数据预处理,运用MEA对Elman神经网络的权值和阈值参数进行寻优,以此建立腐蚀管道剩余寿命组合预测模型。选取某一管段为例,借助MATLAB进行仿真训练与预测。结果表明,该模型与其他两种传统单一模型相比误差小且有更高的预测精度及泛化能力,为管道剩余寿命研究提供了新思路,也为油气输送系统风险防范和维修管理提供了参考依据。

MEA二元复合胺溶液对CO_(2)吸收的研究进展

全球温室效应日益加剧,CO_(2)减排刻不容缓,乙醇胺(MEA)法作为目前工业上应用最广泛、技术最成熟的烟气CO_(2)吸收方法,具有吸收速率快、成本低的优点,但是其能耗大、吸收量小和易损耗的缺点也很明显。针对目前常见的MEA二元复合胺溶液展开对比分析,阐述了MEA二元复合胺溶液的研究进展,总结了MEA吸收溶液中加入其他醇胺溶液形成二元复合胺溶液后在吸收速率、吸收量和再生能耗等方面对CO_(2)吸收效果不同程度的改善情况。基于总结与分析,提出了吸收剂开发需要从吸收机理、溶解度、吸收负荷、解吸速率、解吸操作条件以及再生能耗等方面进行综合比选的思路,可为新型吸收剂的开发提供一定的指导。

基于MEA/烟气CO_(2)捕集系统的工艺模拟和吸收塔高度对模拟的影响分析

目的对MEA/烟气CO_(2)捕集系统进行工艺模拟计算,研究分析理论塔板数和填料高度对模拟计算的影响。方法采用Aspen HYSYS软件,对吸收塔采用不同填料高度和不同理论塔板数分别在溶液循环量为30 m^(3)/h和40 m^(3)/h时进行模拟计算,对CO_(2)捕集率、再生能耗等结果进行对比分析。结果当吸收塔理论塔板数为20或25时,CO_(2)捕集率模拟值偏低。当吸收塔理论塔板数为20时,再生能耗为采用252Y规整填料(填料高度10 m)吸收塔的1.61~1.87倍,为采用50 mm鲍尔环填料吸收塔(填料高度15 m)的1.53~1.78倍。当吸收塔理论塔板数为25时,再生能耗为采用252Y规整填料(填料高度10 m)吸收塔的1.31~1.38倍,为采用50 mm鲍尔环填料(填料高度15 m)吸收塔的1.24~1.32倍。对于30%(w)的MEA/烟气吸收体系,252Y规整填料高度的临界值为10 m,50 mm鲍尔环填料高度的临界值为15 m;模拟再生能耗为4.10~4.31 GJ/t CO_(2)。结论当吸收塔理论塔板数为20或25时,再生能耗模拟计算值偏高,Aspen HYSYS软件在能耗模拟方面适应性较差。采用Aspen HYSYS模拟计算时,建议先对吸收塔结构参数定义后再进行系统模拟,可得到相对准确的模拟计算结果。

Aircraft Measurements of the Microphysical Properties of Stratiform Clouds with Embedded Convection

The presence of embedded convection in stratiform clouds strongly affects ice microphysical properties and precipitation formation.In situ aircraft measurements,including upward and downward spirals and horizontal penetrations,were performed within both embedded convective cells and stratiform regions of a mixedphase stratiform cloud system on 22 May 2017.Supercooled liquid water measurements,particle size distributions,and particle habits in different cloud regions were discussed with the intent of characterizing the riming process and determining how particle size distributions vary from convective to stratiform regions.Significant amounts of supercooled liquid water,with maxima up to 0.6 g m−3,were observed between−3℃ and−6℃ in the embedded convective cells while the peak liquid water content was generally less than 0.1 g m−3 in the stratiform regions.There are two distinct differences in particle size distributions between convective and stratiform regions.One difference is the significant shift toward larger particles from upper−15℃ to lower−10℃ in the convective region,with the maximum particle dimensions increasing from less than 6000μm to over 1 cm.The particles larger than 1 cm at−10℃ are composed of dendrites and their aggregates.The other difference is the large concentrations of small particles(25–205μm)at temperatures between−3℃ and−5℃ in the convective region,where rimed ice particles and needles coexist.Needle regions are observed from three of the five spirals,but only the cloud conditions within the convective region fit into the Hallett-Mossop criteria.

Aircraft Measurements of Cloud–Aerosol Interaction over East Inner Mongolia

To investigate the potential effects of aerosols on the microphysical properties of warm clouds, airborne observational data collected from 2009 to 2011 in Tongliao, Inner Mongolia, China, were statistically analyzed in this study. The results demonstrated that the vertical distribution of the aerosol number concentration(N_a) was similar to that of the clean rural continent. The average aerosol effective diameter(D_e) was maintained at approximately 0.4 μm at all levels. The data obtained during cloud penetrations showed that there was a progressive increase in the cloud droplet concentration(N_c) and liquid water content(LWC) from outside to inside the clouds, while the Nawas negatively related to the Ncand LWC at the same height. The fluctuation of the N_a, Ncand LWC during cloud penetration was more obvious under polluted conditions(Type 1) than under clean conditions(Type 2). Moreover, the wet scavenging of cloud droplets had a significant impact on the accumulation mode of aerosols, especially on particles with diameters less than 0.4 μm. The minimum wet scavenging coefficient within the cloud was close to 0.02 under Type 1 conditions, while it increased to 0.1 under Type 2 conditions,which proved that the cloud wet scavenging effect under Type 1 conditions was stronger than that under Type 2 conditions.Additionally, cloud droplet spectra under Type 1 conditions were narrower, and their horizontal distributions were more homogeneous than those under Type 2 conditions.

A bi-population immune algorithm for weapon transportation support scheduling problem with pickup and delivery on aircraft carrier deck

The weapon transportation support scheduling problem on aircraft carrier deck is the key to restricting the sortie rate and combat capability of carrier-based aircraft.This paper studies the problem and presents a novel solution architecture.Taking the interference of the carrier-based aircraft deck layout on the weapon transportation route and precedence constraint into consideration,a mixed integer formulation is established to minimize the total objective,which is constituted of makespan,load variance and accumulative transfer time of support unit.Solution approach is developed for the model.Firstly,based on modeling the carrier aircraft parked on deck as convex obstacles,the path library of weapon transportation is constructed through visibility graph and Warshall-Floyd methods.We then propose a bi-population immune algorithm in which a population-based forward/backward scheduling technique,local search schemes and a chaotic catastrophe operator are embedded.Besides,the randomkey solution representation and serial scheduling generation scheme are adopted to conveniently obtain a better solution.The Taguchi method is additionally employed to determine key parameters of the algorithm.Finally,on a set of generated realistic instances,we demonstrate that the proposed algorithm outperforms all compared algorithms designed for similar optimization problems and can significantly improve the efficiency,and that the established model and the bi-population immune algorithm can effectively respond to the weapon support requirements of carrier-based aircraft under different sortie missions.

Refined Aerodynamic Test of Wide-Bodied Aircraft and Its Application

The large dual-channel wide-bodied aircraft has a long range and a high cruise Mach number.Therefore,its aerodynamic design requires a high level ofwind tunnel test refinement.Based on the requirements of aerodynamic design for the future wide-bodied aircraft and the characteristics of high-speed wind tunnel tests,the error theory is introduced to analyze the factors affecting the accuracy of the test data.This study carries out a series of research on the improvement of refined aerodynamic test technology in an FL-26 wind tunnel,including design and optimization of the support system of wide-bodied aircraft,model attitude angle measurement,Mach number control accuracy,measurement and control system stability,test data correction and perfection,high-precision force balance and standard model development.In addition,the effect of the standard specification of the refined aerodynamic test is investigated to improve the data quality.The research findings have been applied in the standard model test and subsequent models of wide-bodied aircraft.The results show that whenMach numbers are less than 0.9,the control accuracy of Mach numbers in the FL-26 wind tunnel is smaller than 0.001 and the measurement error of attack angle is smaller than 0.01°.Therefore,it has the ability to correct the data influenced by factors,such as support/wall interference,model deformation,floating resistance and airflow deflection angle.The repeatability accuracy of the standard model’s comparison test shows that the lift coefficient is less than or equal to 0.0012,the drag coefficient is less than or equal to 0.00004,pitching moment coefficient is less than or equal to 0.0004.The bending resolution of the model’s deformation measurement is less than 0.2 mm,and the tensional deformation is smaller than 0.04°.The revised aerodynamic data and model deformation measurement results have good agreement with that of the ETW wind tunnel.The results demonstrate that the improved technology presented in this paper can significantly enhance the refined aerodynamic test of wide-bodied aircraft.

Mechanical Dispatch Reliability Prediction for Civil Aircraft Considering Operational Parameters

To effectively predict the mechanical dispatch reliability(MDR),the artificial neural networks method combined with aircraft operation health status parameters is proposed,which introduces the real civil aircraft operation data for verification,to improve the modeling precision and computing efficiency.Grey relational analysis can identify the degree of correlation between aircraft system health status(such as the unscheduled maintenance event,unit report event,and services number)and dispatch release and screen out themost closely related systems to determine the set of input parameters required for the prediction model.The artificial neural network using radial basis function(RBF)as a kernel function,has the best applicability in the prediction of multidimensional,small sample problems.Health status parameters of related systems are used as the input to predict the changing trend ofMDR,under the artificial neural network modeling framework.The case study collects real operation data for a certain civil aircraft over the past five years to validate the performance of the model which meets the requirements of the application.The results show that the prediction quadratic error Ep of the model reaches 6.9×10−8.That is to say,in the existing operating environment,the prediction of the number of delay&cancel events per month can be less than once.The accuracy of RBF ANN,BP ANN and GA-BP ANN are compared further,and the results show that RBF ANN has better adaptability to such multidimensional small sample problems.The efforts of this paper provide a highly efficientmethod for theMDR prediction through aircraft system health state parameters,which is a promising model to enhance the prediction and controllability of the dispatch release,providing support for the construction of the civil aircraft operation system.

Anti-Disturbance Control for Tethered Aircraft System With Deferred Output Constraints

In this paper,we investigate the peaking issue of extended state observers and the anti-disturbance control problem of tethered aircraft systems subject to the unstable flight of the main aircraft,airflow disturbances and deferred output constraints.Independent of exact initial values,a modified extended state observer is constructed from a shifting function such that not only the peaking issue inherently in the observer is circumvented completely but also the accurate estimation of the lumped disturbance is guaranteed.Meanwhile,to deal with deferred output constraints,an improved output constrained controller is employed by integrating the shifting function into the barrier Lyapunov function.Then,by combining the modified observer and the improved controller,an anti-disturbance control scheme is presented,which ensures that the outputs with any bounded initial conditions satisfy the constraints after a pre-specified finite time,and the tethered aircraft tracks the desired trajectory accurately.Finally,both a theoretical proof and simulation results verify the effectiveness of the proposed control scheme.

Statistical Data Analyses on Aircraft Accidents in Japan: Occurrences, Causes and Countermeasures

We investigate the major characteristics of the occurrences, causes of and counter measures for aircraft accidents in Japan. We apply statistical data analysis and mathematical modeling techniques to determine the relations among economic growth, aviation demand, the frequency of aircraft/helicopter accidents, the major characteristics of the occurrence intervals of accidents, and the number of fatalities due to accidents. The statistical model analysis suggests that the occurrence intervals of accidents and the number of fatalities can be explained by probability distributions such as the exponential distribution and the negative binomial distribution, respectively. We show that countermeasures for preventing accidents have been developed in every aircraft model, and thus they have contributed to a significant decrease in the number of accidents in the last three decades. We find that the major cause of accidents involving large airplanes has been weather, while accidents involving small airplanes and helicopters are mainly due to the pilot error. We also discover that, with respect to accidents mainly due to pilot error, there is a significant decrease in the number of accidents due to the aging of airplanes, whereas the number of accidents due to weather has barely declined. We further determine that accidents involving small and large airplanes mostly occur during takeoff and landing, whereas those involving helicopters are most likely to happen during flight. In order to decrease the number of accidents, i) enhancing safety and security by further developing technologies for aircraft, airports and air control radars, ii) establishing and improving training methods for crew including pilots, mechanics and traffic controllers, iii) tightening public rules, and iv) strengthening efforts made by individual aviation-related companies are absolutely necessary.

Investigation of Nonlinear PI Multi-loop Control Strategy for Aircraft HVDC Generator System with Wound Rotor Synchronous Machine

In order to enhance the transient performance of aircraft high voltage DC(HVDC)generation system with wound rotor synchronous machine(WRSM)under a wide speed range,the nonlinear PI multi-loop control strategy is proposed in this paper.Traditional voltage control method is hard to achieve the dynamic performance requirements of the HVDC generation system under a wide speed range,so the nonlinear PI parameter adjustment,load current feedback and speed feedback are added to the voltage and excitation current double loop control.The transfer function of the HVDC generation system is derived,and the relationship between speed,load current and PI parameters is obtained.The PI parameters corresponding to the load at certain speed are used to shorten the adjusting time when the load suddenly changes.The dynamic responses in transient processes are analyzed by experiment.The results illustrate that the WRSM HVDC generator system with this method has better dynamic performance.

基于MEA-BP的NTC热敏电阻温度传感器非线性补偿研究

热敏电阻作为温度传感器其阻温特性表现为非线性,在工程实际温度测量中存在一定的非线性误差,精度较低。论文使用NTC热敏电阻温度传感器作为研究对象,针对其存在的非线性问题,通过MEA(思维进化算法)优化BP神经网络模型从而实现对NTC热敏电阻温度传感器的非线性补偿,论文简要阐述了有关温度传感器补偿的相关方法与研究成果,分析了热敏电阻的阻温特性、工作原理,介绍了MEA-BP的模型构建,补偿原理与方法,利用5种评估标准对比传统RBF与BP神经网络模型。结果表明该补偿模型在各个评价指标上均优于传统RBF与BP神经网络,具有补偿精度更好、稳定性更强等优势,在测控、军工、航空等众多领域有一定实用价值。

基于MEA-BP神经网络的印刷车间能耗预测

随着制造业的发展,能源需求日益增大,实现节能减排刻不容缓。针对印刷车间的能耗的复杂性,提出了利用MEA算法改进的BP神经网络模型作为解决能耗预测的办法。MEA算法利用算法解空间内多个子群体共同寻找最优值个体,采用“趋同”以及“异化”的有机结合,输出最优个体,解码得到网络的权值和阈值,建立了MEA-BP神经网络预测模型。可以有效地改善BP神经网络的收敛率和泛化能力,保证了权值和阈值的全局代表性。经模拟试验,实验证明了MEA-BP神经网络具有较好的预测精度,能够较好地运用在印刷车间能耗的预测方面。

SAR-AIRcraft-1.0:高分辨率SAR飞机检测识别数据集

针对合成孔径雷达(SAR)图像中飞机散射点离散以及背景强干扰造成虚警的问题,该文提出了一种结合散射感知的SAR飞机检测识别方法。一方面,通过上下文引导的特征金字塔模块来增强全局信息,减弱复杂场景中强干扰的影响,提高检测识别的准确率。另一方面,利用散射关键点对目标进行定位,设计散射感知检测模块实现对回归框的细化校正,增强目标的定位精度。为了验证方法有效性、同时促进SAR飞机检测识别领域的研究发展,该文制作并公开了一个高分辨率SAR-AIRcraft-1.0数据集。该数据集图像来自高分三号卫星,包含4,368张图片和16,463个飞机目标实例,涵盖A220,A320/321,A330,ARJ21,Boeing737,Boeing787和other共7个类别。该文将提出的方法和常见深度学习算法在构建的数据集上进行实验,实验结果证明了散射感知方法的优异性能,并且形成了该数据集在SAR飞机检测、细粒度识别、检测识别一体化等不同任务中性能指标的基准。

GM(1,1)-MEA-BP组合模型电能消耗预测及应用

为解决传统单一模型泛化能力弱、预测精度低等问题,提出一种GM(1,1)灰色模型和MEA-BP神经网络的组合预测模型,解决了GM(1,1)预测模型对能耗的预测受时间因素影响随机波动大及预测精度较低等问题,融合MEA-BP神经网络并行计算、强容错力以及分布式信息存储等优势,减少了因数据波动而影响预测结果精度的情况,解决了误差无法反馈调整等问题。选取1985—2020年全国电能消耗总量为建模数据,与线性回归、三指数平滑、GM(1,1)、BP神经网络、MEA-BP神经网络等模型的预测结果进行分析比较。结果表明:GM(1,1)-MEA-BP组合模型相较于其他模型,预测精度最高,误差值最小,MAPE值达到0.0065,RMSE值达到977.9961。通过实例证明了GM(1,1)-MEA-BP组合模型对电能消耗量预测具备较高的精度,可为国家在能源方面宏观智能调度提供依据。

氢燃料电池电堆气体吹扫条件对MEA漏量的影响

氢燃料电池电堆吹扫是优化系统吹扫策略的重要课题。本文通过研究10片电堆在不同吹扫条件下经过加速耐久吹扫循环试验后的MEA透氢电流密度与吹扫条件的关系,吹扫条件包括:温度、时间、流量。研究发现随着吹扫温度的增加,MEA的透氢电流密度呈增大的趋势,即吹扫温度越高,MEA漏量增加;随着吹扫时间的增加,MEA的透氢电流密度呈增大的趋势,即吹扫时间越长,MEA漏量增加;相比于吹扫温度和吹扫时间,吹扫流量对MEA耐久性的影响更大,当吹扫流量超过某一阈值时,MEA的漏量急剧增加,最终因发生机械衰减导致MEA失效,值得一提的是,虽然MEA质子交换膜发生失效,但是电堆的性能并未发生明显降低,这可能跟漏点发生在电堆出口有关。本文的研究结果对开发MEA新材料或改进其结构,优化燃料电池系统吹扫策略方面提供指导。

氢燃料电池关键零部件MEA的选型验证

氢燃料电池电堆降本举措是我国氢燃料电池行业发展的重中之重,关键零部件的国产化则是诸多降本举措中的重要环节。本文通过研究国产MEA选型和验证的案例,从燃料电池膜电极的发电性能、低温性能以及衰减和耐久等几个方面,对燃料电池工程化过程中MEA关键技术指标验证和确定提供了指导。