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Characteristics of reattached boundary layer in shock wave and turbulent boundary layer interaction

Chinese journal of Aeronautics 2022年第6期35卷 172-185页

作者： Fulin tong junyi DUAN Xinliang LI State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang 621000China Computational Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang 621000China LHD Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

The reattached boundary layer in the interaction of an oblique shock wave with a flatplate turbulent boundary layer at Mach number 2.25 is studied by means of Direct Numerical Simulation(DNS).The numerical results are carefully compared with available experimental and DNS data in terms of turbulence statistics,wall pressure and skin *** coherent vortex structures are significantly enhanced due to the shock interaction,and the reattached boundary layer is characterized by large-scale structures in the outer *** space-time correlation of fluctuating wall shear stress and streamwise velocity fluctuation reveals that the structural inclination angle exhibits a gradual decrease during the recovery *** scale interactions are analyzed by using a twopoint amplitude modulation correlation.A possible mechanism is proposed to account for the strong amplitude modulation in the downstream ***,the mean skin-friction is decomposed to understand the physically informed *** the upstream Turbulent Boundary Layer(TBL),the contribution associated with the Turbulence Kinetic Energy(TKE)production is greatly amplified,while the spatial growth contribution induced by the pressure gradient largely inhibits skin-friction *** on bidimensional empirical mode decomposition,the turbulence kinetic energy production contribution is further split into different terms with specific spanwise length scales.

关键词： Amplitude modulation Shock wave Skin friction decomposition Structural inclination angle Turbulent boundary layer

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Direct numerical simulation of impinging shock wave and turbulent boundary layer interaction over a wavy-wall

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Chinese journal of Aeronautics 2021年第5期34卷 350-363页

作者： Fulin tong Dong SUN Xinliang LI LHD Institute of MechanicsChinese Academy of SciencesBeijing 100190China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianvang 621000China Computational Aerodynamics Institute China Aerodynamics Research and Development CenterMicmyang 621000China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

The interaction of an impinging oblique shock wave with an angle of 30°and a supersonic turbulent boundary layer at Ma_(∞)=2.9 and Re_(θ)=2400 over a wavy-wall is investigated through direct numerical simulation and compared with the interaction on a flat-plate under the same flow conditions.A sinusoidal wave with amplitude to wavelength ratio of 0.26 moves in the streamwise direction and is uniformly distributed across the spanwise *** influences of the wavy-wall on the interaction,including the characterization of the flow field,the skin-friction,pressure and the budget of turbulence kinetic energy,are systematically *** region of separation grows slightly and decomposes into four *** peaks of skin-friction are observed at the rear part of the interaction *** low-frequency shock motion can be seen in the wall pressure *** of the turbulence kinetic energy budget indicate that both diffusion and transport significantly increase near the crests,balanced by an amplified dissipation in the near-wall *** orthogonal decomposition analyses show that the most energetic structures are associated with the separated shock and the shear layer over the *** the bubbles in the first two troughs are dominated by a low-frequency enlargement or shrinkage.

关键词： Direct numerical simulation Low-frequency unsteadiness Shock waves Turbulent boundary layer Wavy-wall

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Data-driven intelligent modeling framework for the steam cracking process

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Chinese journal of Chemical Engineering 2023年第9期61卷 237-247页

作者： Qiming Zhao Kexin Bi tong Qiu Department of Chemical Engineering Tsinghua UniversityBeijing 100084China Beijing Key Laboratory of Industrial Big Data Systems and Applications Tsinghua UniversityBeijing 100084China School of Chemical Engineering Sichuan UniversitySichuan 610065China Department of Bioprocess Engineering Institute of BiotechnologyTechnische Universität BerlinBerlin 10623Germany

Steam cracking is the dominant technology for producing light olefins,which are believed to be the foundation of the chemical *** models of the cracking process can boost production efficiency and profit *** advancements in machine learning research have recently enabled data-driven solutions to usher in a new era of process ***,its practical application to steam cracking is still hindered by the trade-off between prediction accuracy and computational *** research presents a framework for data-driven intelligent modeling of the steam cracking *** data preparation and feature engineering techniques provide computational-ready datasets for the framework,and feedstock similarities are exploited using k-means *** propose LArge-Residuals-Deletion Multivariate Adaptive Regression Spline(LARD-MARS),a modeling approach that explicitly generates output formulas and eliminates potentially outlying *** framework is validated further by the presentation of clustering results,the explanation of variable importance,and the testing and comparison of model performance.

关键词： Mathematical modeling Data-driven modeling Process systems Steam cracking Clustering Multivariate adaptive regression spline

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Periodic event-triggered formation control for multi-UAV systems with collision avoidance

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Chinese journal of Aeronautics 2022年第8期35卷 193-203页

作者： tong WU jie WANG Bailing TIAN School of Artificial Intelligence Hebei University of TechnologyTianjin 300130China Institute of Artificial Intelligence University of Science and Technology BeijingBeijing 100083China School of Electric and Information Engineering Tianjin UniversityTianjin 300072China

In this paper,periodic event-triggered formation control problems with collision avoidance are studied for leader–follower multiple Unmanned Aerial Vehicles(UAVs).Firstly,based on the Artificial Potential Field(APF)method,a novel sliding manifold is proposed for controller design,which can solve the problem of collision ***,the event-triggered strategy is applied to the distributed formation control of multi-UAV systems,where the evaluation of the event condition is *** addition,the exclusion of Zeno behavior can be guaranteed by the inter-event time between two successive trigger events have a positive lower ***,a periodic event-triggered mechanism is developed for formation control based on the continuous eventtriggered *** periodic trigger mechanism does not need additional hardware circuits and sophisticated sensors,which can reduce the control *** stability of the control system is proved by the Lyapunov function ***,some numerical simulations are presented to illustrate the effectiveness of the proposed control protocol.

关键词： Collision avoidance Distributed formation control Event-triggered strategy Leader-follower method Multiple Unmanned Aerial Vehicles(UAVs)

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Effect of roasting activation of rare earth molten salt slag on extraction of rare earth,lithium and fluorine

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journal of Rare Earths 2023年第2期41卷 300-308页

作者： Zhifang tong Xiaofei Hu Hao Wen Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341099China

A new process was proposed to extract rare earth elements(REEs),Li and F from electrolytic slag of rare earth molten salt by synergistic roasting and acid ***,the thermodynamic analysis of roasting reaction was carried out,then the effects of roasting factors on leaching REEs,Li and F in slag were *** additions,the mineral phase and morphology of molten salt slag,roasting slag and acid leaching slag were characterized,and the migration mechanism of REES,Li and F minerals in roasting and leaching process was *** results show that the synergistic roasting and activation of molten salt slag by CaO and Al_(2)(SO_(4))_(3)are thermodynamically *** optimum roasting conditions are as follows:molten salt slag of 20 g,Al_(2)(SO_(4))_(3)of 31.25 g and CaO of 6.25 g,roasting temperature of 1173.15 K and reaction time of 2 h,under this condition,the leaching rates of Nd,Pr,Gd,Li and F are 92.47%,91.56%,91.08%,96.69%and 96.8%,respectively.X-ray powder diffraction(XRD)and scanning electron microscopy-energy dispersive X-ray spectroscopy(SEM-EDS)analysis show that the rare earth fluoride(REF3)in molten salt slag transforms into soluble rare earth oxide(REO)after roasting and *** leaching,the leaching residue is mainly strip CaSO4,indicating that REES,Li and F can be fully extracted from molten salt slag.

关键词： Rare earth molten salt electrolytic slag Thermodynamic analysis Activation roasting Efficient extraction

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Coordinating gibberellin and brassinosteroid signaling beyond Green Revolution

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journal of Genetics and Genomics 2023年第7期50卷 459-461页

作者： Hongning tong Chengcai Chu National Key Facility for Crop Gene Resources and Genetic Improvement Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing 100081China Guangdong Laboratory for Lingnan Modern Agriculture State Key Laboratory for Conservation and Utilization of Subtropical Agro-BioresourcesCollege of AgricultureSouth China Agricultural UniversityGuangzhouGuangdong 510642China

The Green Revolution,which took place in the 1960s,was instrumental in increasing grain yields and mitigating the world’s food *** semi-dwarfing crops was a critical activity that significantly improved lodging resistance,field management,and harvesting *** molecular genetic studies revealed that the semi-dwarfing genes used in rice and wheat,two major staple crops,are related to the plant hormone gibberellin(GA).In rice,SD1 encodes a defective GA synthetic enzyme GA20ox-2,while in wheat,Rht-1(Rht-B1b or Rht-D1b)encodes the gain-of-function form of the GA signaling inhibitors known as DELLA proteins(Peng et al.,1999;Sasaki et al.,2002).However,defects in either GA synthesis or signaling can decrease nitrogen use efficiency(NUE)and potentially lead to inferior grain ***,the success of the Green Revolution relies heavily on the massive input of nitrogen fertilizer,which causes severe environmental issues.

关键词： Wheat BR GA Green Revolution

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Data driven discovery of an analytic formula for the life prediction of Lithium-ion batteries

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Progress in Natural Science:Materials International 2022年第6期32卷 793-799页

作者： jie Xiong tong-Xing Lei Da-Meng Fu jun-Wei Wu tong-Yi Zhang School of Materials Science and Engineering Harbin Institute of Technology Hong Kong University of Science and Technology (Guangzhou)

Predicting the cycle life of Lithium-Ion Batteries(LIBs) remains a great challenge due to their complicated degradation *** present work employs an interpretative machine learning of symbolic regression(SR) to discover an analytic formula for LIB life prediction with newly defined *** novel features are based on the discharging energies under the constant-current(CC) and constant-voltage(CV) modes at every five cycles *** cycle life is affected by the CC-discharging energy at the 15th cycle(E15-CCD) and the difference between the CC-discharging energies at the 45th cycle and 95th cycle(Δ45-95).The cycle life highly correlates with a simple indicator(E15-CCD-3)/Δ45-95with a Pearson correlation coefficient of *** machine learning tools provide a rapid and accurate prediction of cycle life at the early stage.

关键词： Symbolic regression Machine learning Cycle life prediction Lithium-ion batteries

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MICROWAVE PERMEABILITY SPECTRA OF SPUTTERED Fe-Co-B SOFT MAGNETIC THIN FILMS

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Acta Metallurgica Sinica(English Letters) 2008年第6期21卷 419-424页

作者： j.S. Liao Z.K. Feng j. Qiu Y. Q. tong Department of Electronic Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

Permeability characteristics of sputtered soft magnetic Fe40Co40B20 thin films are investigated in the range of O. 5 to 5 GHz by a shortened microstrip transmission line perturbation method. Excellent microwave permeability is achieved at 0.4 Pa argon pressure： fr is 3.32 GHz, the real and imaginary part of permeability at 0.5 GHz are 104 and 61, respectively. In addition, the thickness effect on permeability is also studied. The minimum damping can be achieved at the thinnest film. Different sources contributed to in-plane anisotropy are discussed briefly. The deviation between the peak frequency of the imaginary part and the zero-crossing frequency of the real part of permeability is also presented.

关键词： Fe-Co-B In-plane anisotropy Magnetic thin films Permeability

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Lower Triassic and Induan-Olenekian Boundary in Chaohu,Anhui Province,South China

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Acta Geologica Sinica(English Edition) 2011年第2期85卷 399-407页

作者： tong jinnan ZHAO Laishi Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of Geosciences Wuhan 430074 China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China

Since the West Pingdingshan Section in Chaohu was proposed as the candidate of the Global Stratotype Section and Point of the Induan-Olenekian boundary in 2003, the Lower Triassic of Chaohu has been extensively studied. Based on the studies on the Lower Triassic of Chaohu, （1） a continuous conodont zonation is established, which has become an important reference for Lower Triassic stratigraphic correlation over the world; （2） the First Appearance Datum of conodont Neospathodus waageni was suggested and has been basically accepted as the primary marker to define the InduanOienekian boundary; （3） a characteristic Lower Triassic excursion of carbon isotopes was brought to light and has been proven to be not only an excellent index for the stratigraphic correlation but also a unique indication for the perturbation of ecological environments in the aftermath of the end-Permian mass extinction; （4） a magnetostratigraphic sequence is constituted with a certain biostratigraphic control in the low-latitude region and it presents an important correlation to the Boreal sequence; （5） a cyclostratigraphic study provides an alternative method to constrain the age of the chronostratigraphic units; and （6） a scheme of the Olenekian subdivision is recently suggested to define the boundary between the Smithian and Spathian Substages. In addition, Chaohu is also the type locality of the Chaohuan Stage, the upper stage of the Lower Triassic in the China Chronostratigraphic ***, the Lower Triassic of Chaohu is not only a classic sequence in South China, but also a key reference sequence to the investigation of the corresponding stratigraphy and geological events over the world. The recent achievements are viewed here for an overall understanding of the sequence. Then the current situation of the Induan-Olenekian and Smithian-Spathian boundaries is discussed to provide a reference for later works.

关键词： Lower Triassic Induan-Olenekian boundary Smithian-Spathian boundary Global Stratotype Section and Point Chaohu China

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Effective technology for processing industrial volatile organic compounds by the atmospheric pressure microwave plasma torch

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journal of Electronic Science and Technology 2023年第2期21卷 87-94页

作者： Da-Shuai Li Ling tong Yangtze Delta Region Institute(Huzhou) University of Electronic Science and Technology of ChinaHuzhou313001China School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu611731China

In this study,we investigated the abatement of volatile organic compounds(VOCs)by the atmospheric pressure microwave plasma torch(AMPT).To study the treatment efficiency of AMPT,we used the toluene and water-based varnish to simulate VOCs,*** measuring the compounds and contents of the mixture gas before/after the microwave plasma process,we have calculated the treatment efficiency of *** experimental results show that the treatment efficiency of AMPT for toluene with a concentration of 17.32×10^(4) ppm is up to 60 g/kWh with the removal rate of 86%.For the volatile compounds of water-based varnish,the removal efficiency is up to 97.99%.We have demonstrated the higher potential for VOCs removal of the AMPT process.

关键词： Atmospheric microwave plasma Industrial volatile organic compounds(VOCs)processing Spectroscopic diagnostic

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