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Adaptive composite anti-disturbance control for heavy haul trains

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Transportation Safety and Environment 2024年第1期6卷 75-82页

作者： Longsheng Chen Hui Yang school of Electrical and Automation engineering East China Jiaotong UniversityNanchang 33013JiangxiChina school of Aircraft engineering Nanchang Hangkong UniversityNanchang 330063JiangxiChina

In this paper,an adaptive composite anti-disturbance control of heavy haul trains(HHTs)is ***,the mechanical principle and characteristics of couplers are analysed and the longitudinal multi-particles nonlinear dynamic model of HHTs is established,which can satisfy that the forces of vehicles in different positions are ***,a radial basis function network(RBFNN)is employed to approximate the uncertainties of HHTs,and a nonlinear disturbance observer(NDO)is constructed to estimate the approximation error and external *** indicate and improve the approximation accuracy,a serial-parallel identification model of HHTs is constructed to generate a prediction error,and an adaptive composite anti-disturbance control scheme is developed,where the prediction error and tracking error are employed to update RBFNN weights and an auxiliary variable of ***,the feasibility and effectiveness of the proposed control scheme are demonstrated through the Lyapunov theory and simulation experiments.

关键词： heavy haul train(HHT) radial basis function neural network nonlinear disturbance observer(NDO) serial-parallel identification model composite anti-disturbance control

Numerical analysis of wind effects on aerodynamic characteristics of a ducted fan

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Chinese Journal of Aeronautics 2024年第5期37卷 263-280页

作者： Yiwei LUO Tianfu AI Yuhang HE Bin XU Yuping QIAN Yangjun ZHANG State Key Laboratory of Intelligent Green Vehicle and Mobility School of Vehicle and MobilityTsinghua UniversityBeijing 100084China Key Laboratory of Conveyance and Equipment Ministry of Education East China Jiaotong UniversityNanchang 330013China Vehicle Research Center School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

Ducted fans have been extensively used in Unmanned Aerial Vehicles(UAVs)for a variety of missions because of high efficiency,high safety and low ***,as a kind of typical meteorological condition,brings significant aerodynamic interference to the ducted fan,which seriously threatens flight stability and *** this work,the numerical simulation with the Unsteady Reynolds Averaged Navier-Stokes(URANS)method and the sliding mesh technique is performed to evaluate the steady wind *** results show that the wind will lead to serious unsteady effects in the flow field,and the thrust fluctuates at the blade passing frequency of 200 *** the wind speed increases,the rotor thrust increases,the duct thrust decreases,and the total thrust changes *** instability may occur when the wind speed exceeds 8 m/*** the angle of low-speed wind increases,the rotor thrust changes little,the duct thrust increases,and the total thrust *** addition,we figure out that cases with the same crosswind ratio are similar in results,and increasing the rotating speed or fan radius is beneficial to performance improvement in *** findings are essential to the ducted fan design and UAV flight control design for stable and safe operations in wind conditions.

关键词： Unmanned Aerial Vehicle(UAV) Ducted fan Wind effect Thrust fluctuations Computational Fluid Dynamics(CFD)

Numerical Simulation of Radial Ultrasonic Assisted MIG Welding Arc

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Journal of Shanghai jiaotong university(Science) 2024年第2期29卷 330-338页

作者：洪蕾肖皓叶佳马国红 Key Laboratory of Lightweight and High Strength Structural Materials of Jiangxi Province School of Mechanical EngineeringNanchang UniversityNanchang 330031China Applied Materials Inc.Santa ClaraCA 95054-3299USA

The numerical simulation of arc was carried out for both conventional melt inert gas(MIG)welding and ultrasonic assisted melt inert gas(U-MIG)*** on the model established by Fluent,the arc shape,temperature field,and potential distribution were *** study found that the shape of the arc changed when ultrasonic was added radially;the high-temperature area of the arc stretched,and the temperature peak *** as the current increased,the increase in temperature *** addition,under the same conditions,the potential of U-MIG decreased and the pressure on the workpiece *** verify the accuracy of the simulation results,welding experiments under identical conditions were carried out,and a high-speed camera was used to collect dynamic pictures of the *** simulation results were in a favorable agreement with the experimental results,which provided a certain reference value for ultrasonic assisted arc welding.

关键词： numerical simulation welding arc ultrasonic arc welding arc temperature

Microstructural and thermal properties of coal measure sandstone subjected to high temperatures

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Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 2909-2921页

作者： Weijing Xiao Dongming Zhang Shujian Li Mingyang Wu school of Civil engineering and Architecture East China Jiaotong UniversityNanchang330013China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400044China Yunnan Phosphate Chemical Group Co. Ltd.Kunming650600China National engineering and Technology Research Center for Development and Utilization of Phosphate Resources Kunming650600China State Key Laboratory of Geomechanics and Geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

To study the microscopic structure,thermal and mechanical properties of sandstones under the influence of temperature,coal measure sandstones from Southwest china are adopted as the research object to carry out high-temperature tests at 25℃-1000℃.The microscopic images of sandstone after thermal treatment are obtained by means of polarizing microscopy and scanning electron microscopy(SEM).Based on thermogravimetric(TG)analysis and differential scanning calorimetric(DSC)analysis,the model function of coal measure sandstone is explored through thermal analysis kinetics(TAK)theory,and the kinetic parameters of thermal decomposition and the thermal decomposition reaction rate of rock are *** the uniaxial compression experiments,the stress‒strain curves and strength characteristics of sandstone under the influence of temperature are *** results show that the temperature has a significant effect on the microstructure,mineral composition and mechanical properties of *** particular,when the temperature exceeds 400℃,the thermal fracture phenomenon of rock is obvious,the activity of activated molecules is significantly enhanced,and the kinetic phenomenon of the thermal decomposition reaction of rock appears *** mechanical properties of rock are weakened under the influence of rock thermal fracture and mineral thermal *** research results can provide a reference for the analysis of surrounding rock stability and the control of disasters caused by thermal damage in areas such as underground coal gasification(UCG)channels and rock masses subjected to mine fires.

关键词： Rock mechanics Coal measure sandstone Micromorphology Thermal damage

Sustainable Asphalt Concrete Containing RAP and Coal Gangue Aggregate:Performance,Costs,and Environmental Impact

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Journal of Renewable Materials 2022年第8期10卷 2263-2285页

作者： Yuquan Yao Jie Gao Jiangang Yang Bocheng Huang Liang Song school of Highway Chang’an UniversityXi’an710064China school of Civil engineering and Architecture East China Jiaotong UniversityNanchang330013China Institute of Road engineering East China Jiaotong UniversityNanchang330013China Fujian Expressway Maintenance engineering Co. Ltd.Fuzhou350001China College of Transportation engineering Tongji UniversityShanghai201804China Xinjiang NABA Expressway Development Co. Ltd.Urumqi830006China

The shortage of natural aggregates is becoming a severe problem in the pavement industry *** address this issue,in this study,an effort was made to use reclaimed asphalt pavement(RAP)and coal gangue(CG)as coarse and fine aggregate,respectively for producing the hot mix asphalt(HMA).As the replacement of natural aggregate,there were seven types of HMA containing 20%and 40%RAP coarse aggregate content,and 10%and 25%CG fine aggregate content were designed and *** addition,Marshall Stability test,rutting resistance test,immersion Marshall test,freezing-thaw splitting test,moisture-induced sensitivity test,and low-temperature semicircle bending test were *** results show that the properties of the asphalt mixture containing both RAP and CG meet the Chinese specification through it is slightly lower than the virgin asphalt ***,the addition of 40%RAP coarse aggregate and 25%CG fine aggregate to asphalt mixes can significantly reduce manufacturing costs,energy consumption,and CO_(2)emissions by 29.4%,19.8%,and 21.9%,respectively,compared to the virgin asphalt *** finding of this study contributes to current knowledge by investigating the feasibility of jointly using the RAP and CG in asphalt mixture,which could be interested by both industry and academic society.

关键词： Reclaimed asphalt pavements(RAP) coal gangue(CG) mechanical properties cost analysis environmental impact

Multifunctional silicene/CeO_(2)heterojunctions:Desirable electronic material and promising water-splitting photocatalyst

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Chinese Chemical Letters 2022年第8期33卷 3947-3950页

作者： Liang Xu Jian Zeng Quan Li Xin Luo Tong Chen Jingjing Liu Ling-Ling Wang Energy Materials Computing Center School of Energy and Mechanical EngineeringJiangxi University of Science and TechnologyNanchang 330013China Department of Applied Physics School of ScienceEast China Jiaotong UniversityNanchang 330013China Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education School of Physics and ElectronicsHunan UniversityChangsha 410082China

The first-principles calculations demonstrate that covalently bonded(cb)heterojunction and van der Waals(vd W)heterojunction can coexist in silicene/CeO_(2) heterojunctions,due to the different stacking ***,the cb heterojunction with band gap of 1.97 e V,forms a type-II heterojunction,exhibits good redox performance and has high-effective optical absorption spectra,thus it is a promising photocatalyst for overall water ***,for the vd W heterojunction,the Dirac cone of silicene is well kept on CeO_(2) semiconducting substrate,with a considerable energy gap of 0.43 e V,which can be an ideal material in building silicene-based electronic *** results may open a new gateway in both of nanoelectronic device and energy conversion for silicene/Ce O2 nanocomposites.

关键词： Silicene CeO_(2) Photocatalyst Interfacial interaction Dirac cone

Z-scheme systems of ASi_(2)N_4(A=Mo or W)for photocatalytic water splitting and nanogenerators

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Tungsten 2022年第1期4卷 52-59页

作者： Jian Zeng Liang Xu Xin Luo Tong Chen Shuai-Hao Tang Xin Huang Ling-Ling Wang Energy Materials Computing Center School of Energy and Mechanical EngineeringJiangxi University of Science and TechnologyNanchang 330013China Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education School of Physics and ElectronicsHunan UniversityChangsha 410082China Department of Applied Physics School of ScienceEast China Jiaotong UniversityNanchang 330013China

Z-scheme heterojunction catalysts have received great attention due to their efficient ability to separate electrons and ***,using the first-principles calculations,we designed a series of promising two-dimensional(2D)/2D Z-scheme systems with interlayer inequivalent,including MoSi_(2)N_(4)/MoSi_(2)N_(4),WSi_(2)N_(4)/WSi_(2)N_(4) and MoSi_(2)N_(4)/WSi_(2)N_(4).Molecular dynamics simulation and phonon dispersion show that they have sufficient environmental *** inequivalent structure between the layers caused the directional formation of built-in potentials,driving the transfer of net charge between layers,which greatly enhanced their catalytic *** smaller band gap and enhanced light absorption performance further revealed their perfect catalytic ***,all they met the redox potential requirements of water splitting in a range of pH 0-7,demonstrate they are very remarkable photocatalysts for H_(2)*** interestingly,they also have good sliding ferroelectricity,and the opposite built-in potential can be obtained by sliding between layers,which is very promising for future *** works may provide new insights into energy conversion devices.

关键词： Tungsten MoSi_(2)N_4 WSi_(2)N_4 Z-scheme systems Water splitting Nanogenerators First-principles calculations

Surface grain refinement mechanism of SMA490BW steel cross joints by ultrasonic impact treatment

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International Journal of Minerals,Metallurgy and Materials 2017年第4期24卷 410-414页

作者： Bo-lin He Lei Xiong Ming-ming Jiang Ying-xia Yu Li Li school of mechanical & Electronic engineering East China Jiaotong University Nanchang 330013 China

Ultrasonic impact treatment(UIT) is a postweld technique for improving the fatigue strength of welded joints. This technique makes use of ultrasonic vibration to impact and plastically deform a weld toe and can achieve surface grain refinement of the weld toe,which is considered as the main reason for the improvement of fatigue strength. In this paper,the microstructure of the surface of a treated weld toe was observed by metallographic microscopy and transmission electron microscopy(TEM). The results show that UIT could produce severe plastic deformation on the surface layer of the weld toe and the maximum depth of plastic deformation extended to approximately 260 μm beneath the treated surface. Repeated processing could exacerbate the plastic deformation on the surface layer,resulting in finer grains. We can conclude that the surface grain refinement mechanism of SMA490 BW welded joints is related to the high density of dislocation tangles and dislocation walls.

关键词： weathering steel welding ultrasonic impact treatment plastic deformation joints grain refinement

Phase selection and performance of Mg–Cu–Y amorphous composite with different Mg/Cu ratios

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Rare Metals 2014年第1期33卷 91-94页

作者： Di-Qing Wan school of mechanical and electronical engineering East China Jiaotong University

In this article, Mg-Cu-Y alloys with two dif- ferent Mg/Cu ratios （in at%） were prepared using a water- cooled copper mold. Scanning electron microscopy and X-ray diffraction were applied to analyze the microstructure and phase composition. Moreover, corrosion resistance and wear resistance were studied systematically. The results show that both Mg65Cu25Ylo and Mg60Cu30Ylo alloys could form a composition of crystalline and amorphous phases. Although the microstructure of Mg65Cu25Ylo con- sists of an amorphous phase and ：t-Mg, Mg2Cu, and Cu2Y crystalline phases, the microstructure of Mg60Cu30Ylo alloy mainly consists of the amorphous phase and ：t-Mg, Mg2Cu. With reducing Mg/Cu ratio, the alloys have better corrosion resistance and wear resistance. The mechanism has also been discussed in detail.

关键词： Mg-Cu-Y alloy Amorphous composites Corrosion resistance Wear resistance