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Journal of Iron and Steel Research(International) 2023年第4期30卷 749-759页

作者： Lun Fu yu-fei Zhu Bin Yang Chao Yu Hong Xiao National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004HebeiChina

Al/steel composite plate has a wide application prospect,but great differences in properties between Al and steel are observed.It is difficult to obtain high bonding strength by the traditional cold roll bonding process.Al/steel composite plate was thus prepared by cold roll bonding at a reduction rate of 60%after oxidation treatment on the surface to be composited on the steel side.The heat treatment of holding at 400℃ for 1 h and cooling with the furnace was then adopted.The bonding strength,microstructure,and properties of the Al/steel composite plate before and after annealing were analysed and compared through shear test,bending test,tensile test,and micro-characterization.Results show that the shear strengths of the interface before and after annealing are 100 and 80 MPa,respectively.Although the shear strength of the annealed Al/steel composite plate decreases,the bending and overall tensile properties of the composite plate are improved,showing better mechanical properties.

关键词： Al/steel composite plate Oxidation treatment Annealing treatment Shear strength Cold roll bonding

Fourier neural operator with boundary conditions for efficient prediction of steady airfoil flows

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Applied Mathematics and Mechanics(English Edition) 2023年第11期44卷 2019-2038页

作者： yuanjun DAI Yiran AN Zhi LI Jihua ZHANG Chao Yu Department of Machanics and Engineering Science College of EngineeringPeking UniversityBeijing 100871China Beijing Institute of Mechanical and Electrical Engineering Beijing 100074China

An efficient data-driven approach for predicting steady airfoil flows is proposed based on the Fourier neural operator(FNO),which is a new framework of neural networks.Theoretical reasons and experimental results are provided to support the necessity and effectiveness of the improvements made to the FNO,which involve using an additional branch neural operator to approximate the contribution of boundary conditions to steady solutions.The proposed approach runs several orders of magnitude faster than the traditional numerical methods.The predictions for flows around airfoils and ellipses demonstrate the superior accuracy and impressive speed of this novel approach.Furthermore,the property of zero-shot super-resolution enables the proposed approach to overcome the limitations of predicting airfoil flows with Cartesian grids,thereby improving the accuracy in the near-wall region.There is no doubt that the unprecedented speed and accuracy in forecasting steady airfoil flows have massive benefits for airfoil design and optimization.

关键词： deep learning(DL) Fourier neural operator(FNO) steady airfoil flow

Stochastic analysis of load-transfer mechanism of energy piles by random finite difference model

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第4期15卷 997-1010页

作者： chao Shi yu Wang Department of Architecture and Civil Engineering City University of Hong KongTat Chee AvenueKowloonHong KongChina

The surge in demand for renewable energy to combat the ever-escalating climate crisis promotes development of the energy-saving,carbon saving and reduction technologies.Shallow ground-source heat pump(GSHP)system is a promising carbon reduction technology that can stably and effectively exploit subsurface geothermal energy by taking advantage of load-bearing structural elements as heat transfer medium.However,the transformation of conventional geo-structures(e.***.piles)into heat exchangers between the ground and superstructures can potentially induce variable thermal axial stresses and displacements in piles.Traditional energy pile analysis methods often rely on deterministic and homogeneous soil parameter profiles for investigating thermo-mechanical soil-structure interaction,without consideration of soil spatial variability,model uncertainty or statistical uncertainty associated with interpolation of soil parameter profiles from limited site-specific measurements.In this study,a random finite difference model(FDM)is proposed to investigate the thermo-mechanical load-transfer mechanism of energy piles in granular soils.Spatially varying soil parameter profile is interpreted from limited site-specific measurements using Bayesian compressive sensing(BCS)with proper considering of soil spatial variability and other uncertainties in the framework of Monte Carlo simulation(MCS).Performance of the proposed method is demonstrated using an illustrative example.Results indicate that the proposed method enables an accurate evaluation of thermally induced axial stress/displacement and variation in null point(NP)location with quantified uncertainty.A series of sensitivity analyses are also carried out to assess effects of the pile-superstructure stiffness and measurement data number on the performance of the proposed method,leading to useful insights.

关键词： Null point(NP)variation Load-transfer mechanism Bayesian compressive sensing(BCS) Heating and cooling Monte Carlo simulation(MCS)

Mitochondrial transplantation as a promising therapy for mitochondrial diseases

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Acta Pharmaceutica Sinica B 2023年第3期13卷 1028-1035页

作者： Tian-guang Zhang chao-yu Miao Department of Pharmacology Second Military Medical University/Naval Medical UniversityShanghai 200433China

Mitochondrial diseases are a group of inherited or acquired metabolic disorders caused by mitochondrial dysfunction which may affect almost all the organs in the body and present at any age.However,no satisfactory therapeutic strategies have been available for mitochondrial diseases so far.Mitochondrial transplantation is a burgeoning approach for treatment of mitochondrial diseases by recovery of dysfunctional mitochondria in defective cells using isolated functional mitochondria.Many models of mitochondrial transplantation in cells,animals,and patients have proved effective via various routes of mitochondrial delivery.This review presents different techniques used in mitochondrial isolation and delivery,mechanisms of mitochondrial internalization and consequences of mitochondrial transplantation,along with challenges for clinical application.Despite some unknowns and challenges,mitochondrial transplantation would provide an innovative approach for mitochondrial medicine.

关键词： Mitochondria Mitochondrial transplantation Mitochondrial disease Mitochondrial isolation Mitochondrial delivery Mitochondrial storage Mitochondrial transplantation rejection Ethical issue

A Pilot Protection Scheme of DC Lines for MMC-HVDC Grid Using Random Matrix

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Journal of Modern Power Systems and Clean Energy 2023年第3期11卷 950-966页

作者： Senlin yu Xiaoru Wang chao Pang School of Electrical Engineering Southwest Jiaotong UniversityChengdu 611756China IEEE

The over-current capacity of half-bridge modular multi-level converter(MMC)is quite weak,which requests protections to detect faults accurately and reliably in several milliseconds after DC faults.The sensitivity and reliability of the existing schemes are vulnerable to high resistance and data errors.To improve the insufficiencies,this paper proposes a pilot protection scheme by using the random matrix for DC lines in the symmetrical bipolar MMC high-voltage direct current(HVDC)grid.Firstly,the 1-mode voltage time-domain characteristics of the line end,DC bus,and adjacent line end are analyzed by the inverse Laplace transform to find indicators of fault direction.To combine the actual model with the data-driven method,the methods to construct the data expansion matrix and to calculate additional noise are proposed.Then,the mean spectral radiuses of two random matrices are used to detect fault directions,and a novel pilot protection criterion is proposed.The protection scheme only needs to transmit logic signals,decreasing the communication burden.It performs well in high-resistance faults,abnormal data errors,measurement errors,parameters errors,and different topology conditions.Numerous simulations in PSCAD/EMTDC confirm the effectiveness and reliability of the proposed protection scheme.

关键词： Random matrix mean spectral radius MMCHVDC grid 1-mode voltage pilot protection data error

Flexible nest site selection of the endangered Oriental Storks(Ciconia boyciana):Trade-off from adaptive strategies

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Avian Research 2023年第2期14卷 242-249页

作者： Lei Cheng Lizhi Zhou Chao Yu Zhenhua Wei Chunhua Li School of Resources and Environmental Engineering Anhui UniversityHefei230601China School of Biological Engineering Huainan Normal UniversityHuainan232038China Anhui Province Key Laboratory of Wetland Ecosystem Protection and Restoration(Anhui University) Hefei230601China Anhui Shengjin Lake Wetland Ecology National Long-term Scientific Research Base Dongzhi247230China College of Life and Environment Science Huangshan UniversityHuangshan245021China

Nest site selection is a vital component of bird reproduction success,and an adaptive behavior conducted to decrease nest predation risk with avoiding external disturbances.Understanding patterns of nest site selection can provide insights into how species adapt to changes in their habitat and has important conservation implications.In this study,we used microhabitat variables and multi-scale data with a field survey of nest occurrence to determine nest site selection patterns and adaptive strategies of the breeding Oriental Storks(Ciconia boyciana)in different nest areas.Results demonstrate that the nest site microhabitat characteristics of the breeding Oriental Storks significantly differed among the three nesting areas,and nest height was higher in the middle and lower Yangtze River floodplain than in the Northeast China and Bohai Bay nest areas.The food resources and intensity of human disturbance had the greatest effects on the nest site selection of the breeding Oriental Storks.The intensity of human disturbance was positively correlated with the nest height of the breeding Oriental Storks in Bohai Bay and the middle and lower Yangtze River floodplain;however,nest height decreased with the abundance of food resources in the Northeast China nest area.Our findings indicate that the nest site selection patterns of Oriental Storks showed flexible adaptive strategies.In safer environments,nests were lower and closer to food resources,which allows parent storks to invest more in the nestlings.However,in areas where human activity was intense,nests were higher to ensure the safety of their offspring.Some measures that could be taken to improve the breeding habitat of Oriental Storks include increasing the percentage of wetland areas in nesting areas to enhance food resources availability and setting artificial nests at suitable heights in potential nesting grounds to encourage nesting.Finally,the establishment of soft barriers around the nesting areas could increase the safety of nests.

关键词： Adaptive strategies Breeding range expansion Habitat characteristics Nest site selection Oriental storks

Tuning d-spacing of graphene oxide nanofiltration membrane for effective dye/salt separation

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Rare Metals 2023年第2期42卷 418-429页

作者： chao Xing Chang-yu Liu chao Lai Shan-Qing Zhang Center for Clean Environment and Energy School of Environment and ScienceGold Coast CampusGriffith UniversitySouthportQLD4222Australia School of Chemistry and Materials Science Jiangsu Normal UniversityXuzhou221116China School of Biotechnology and Health Sciences Wuyi UniversityJiangmen529020China

The interlayer spacing(i.e.,d-spacing)plays a crucial role in determining the selectivity and permeability of nanofiltration membranes.A high-throughput directional filtration can be achieved by designing and controlling the d-spacing.In this study,the d-spacing of a graphene oxide(GO)membrane was tuned and fixed to the desired value(approximately 0.79 nm)using a solution of polyethyleneimine(PEI)and GO at a PEI/GO mass ratio of15:1.The resultant PEI/GO was deposited on a polyacrylonitrile(PAN)substrate to form a robust composite nanofiltration membrane(a PEI/GO@PAN membrane).The as-prepared membrane exhibited an ultrahigh flux of117.8 L·m^(-2)·h^(-1),and the rejection values for Direct Red80(DR80)and Na_(2)SO_(4)reached 99.7%and<1.7%,respectively;these are desirable values for dye/salt separation.The PEI/GO@PAN membrane exhibited an excellent filtration performance,and had a longer lifespan and excellent reusability because of its reinforced nature.This work suggested that tuning the d-spacing with PEI would be an effective strategy to achieve the anticipated functions of nanofiltration membranes.

关键词： Separation Nanofiltration Graphene oxide Membrane d-spacing

Experimental observations on the nonproportional multiaxial ratchetting of cast AZ91 magnesium alloy at room temperature

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1115-1125页

作者： Binghui Hu yu Lei Hang Li Ziyi Wang Chao Yu Guozheng Kang Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu 610031China

The nonproportional multiaxial ratchetting of cast AZ91 magnesium (Mg) alloy was examined by performing a sequence of axial-torsional cyclic tests controlled by stress with various loading paths at room temperature (RT).The evolutionary characteristics and path dependence of multiaxial ratchetting were discussed.Results illustrate that the cast AZ91 Mg alloy exhibits considerable nonproportional additional softening during cyclic loading with multiple nonproportional multiaxial loading paths;multiaxial ratchetting presents strong path dependence,and axial ratchetting strains are larger under nonproportional loading paths than under uniaxial and proportional45°linear loading paths;multiaxial ratchetting becomes increasingly pronounced as the applied stress amplitude and axial mean stress increase.Moreover,stress-strain curves show a convex and symmetrical shape in axial/torsional directions.Multiaxial ratchetting exhibits quasi-shakedown after certain loading cycles.The abundant experimental data obtained in this work can be used to develop a cyclic plasticity model of cast Mg alloys.

关键词： cast magnesium alloy ratchetting multiaxial loading loading path stress level

Improving BDS broadcast ephemeris accuracy using ground-satellite-link observations

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Satellite Navigation 2022年第1期3卷 85-96,I0004页

作者： Junping Chen Jungang Wang Chao Yu Yize Zhang Bin Wang Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Shanghai Key Laboratory of Space Navigation and Positioning Techniques Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China

The BeiDou Navigation Satellite System(BDS)employs a hybrid constellation including GEO(Geosynchronous Earth Orbit),IGSO(Inclined Geosynchronous Orbit),and MEO(Medium Earth Orbit)satellites,where the GEO and IGSO satellites are critical to providing continuous and reliable Positioning,Navigation,and Timing(PNT)services in the Asia–Pacifc region.To handle the inconsistency between the satellite orbits and clocks in the broadcast ephemeris,which are determined by the Orbit Determination and Time Synchronization(ODTS)and the Two-way Satellite Time Frequency Transfer(TWSTFT)technique,respectively,we present the strategies using ground-satellite-link observations to improve the accuracy of broadcast ephemeris.The clock diferences between the ODTS and TWSTFT techniques are used for correcting the radial orbit component to derive the refned orbits,which are used to generate the refned broadcast ephemeris.The test results show the precision of the refned orbits is improved by 50–60%in the 3-h to 12-h predicted arcs for the GEO satellites,and by 40–50%for the IGSO satellites.Moreover,the validation using satellite laser ranging observations shows the mean precision of the refned broadcast ephemeris is improved by 27%compared to the original one.Applying the proposed strategies in the BDS Operational Control Segment(OCS),the time evolution of BDS Single Point Positioning(SPP)in the period from Jan.2016 to April 2021 is evaluated.The SPP accuracy is improved from 1.94,2.06 and 3.29 m to 1.39,1.85,and 2.39 m in the north,east,and up components,respectively.Further update with the inclusion of BDS-3 satellites improve the corresponding SPP precision to 0.68,0.70 and 1.91 m.

关键词： BDS Broadcast ephemeris TWSTFT Orbit determination

Numerical simulation of formaldehyde distribution characteristics in the high-speed train cabin

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Building Simulation 2024年第2期17卷 285-300页

作者： Fan Wu Hang Dong Chao Yu Hengkui Li Qingmin Cui Renze Xu Key Laboratory of Traffic Safety on Track Ministry of EducationSchool of Traffic&Transportation EngineeringCentral South UniversityChangshaHunan410075China Joint International Research Laboratory of Key Technologies for Rail Traffic Safety ChangshaHunan410075China National&Local Joint Engineering Research Center of Safety Technology for Rail Vehicle ChangshaHunan410075China School of Software Henan University of EngineeringZhengzhouHenan451191China

The global concern over indoor air pollution in public vehicles has grown significantly.With a focus on enhancing passengers’comfort and health,this study endeavors to investigate the distribution characteristics of formaldehyde within a high-speed train cabin by employing a computational fluid dynamics(CFD)model which is experimentally validated in a real cabin scenario.The research focuses on analyzing the impact of air supply modes,temperature,relative humidity,and fresh air change rate on the distribution and concentration of formaldehyde.The results demonstrate that the difference in average formaldehyde concentration between the two air supply modes is below 1.3%,but the top air supply mode leads to a higher accumulation of formaldehyde near the sidewalls,while the bottom air supply mode promotes a more uniform distribution of formaldehyde.Furthermore,the temperature,relative humidity,and fresh air change rate are the primary factors affecting formaldehyde concentration levels,but they have modest effects on formaldehyde’s distribution pattern within the cabin.As the temperature and relative humidity increase,the changes in formaldehyde concentrations in response to variations in these factors become more evident.Importantly,the formaldehyde concentration may surpass the standard limit of 0.10 mg/m^(3)if the fresh air change rate falls below 212 m^(3)/h.This research provides a systematic approach and referenceable results for exploring formaldehyde pollution in high-speed train cabins.

关键词： indoor air pollution formaldehyde CFD simulation high-speed train ventilation