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Non-equilibrium kinetic separation of thulium,yttrium and erbium on the surface of freely rising oil droplets

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Journal of Rare Earths 2024年第1期42卷 200-209,I0007页

作者： Na Sui Shukai Miao Kaihui cui Fancheng Meng Kun Huang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Beijing Key Laboratory of Green Recovery and Extraction of Rare and Precious Metals University of Science and Technology BeijingBeijing100083China Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing100190China

It is difficult to achieve selective separation and enrichment of different rare earths from high abundance yttrium ores efficiently only dependent on their discrepancy in thermodynamic *** present work suggests a new strategy based on non-equilibrium kinetic separation of Er and Tm on the surface of freely rising oil droplets to control the separation order of *** is revealed that the mutual separation of Er/Tm is significantly promoted with the separation coefficient of 2.89 during the non-equilibrium extraction with the addition of diethylenetriaminepentaacetic acid(DTPA).The extraction sequence of Tm,Er and Y can be controlled as Tm>Y>Er,thus Y can be selectively enriched during the process of separation of Er and Tm,Such a sequence is subject to the controllable dissociation rates of RE(Ⅲ)-DTPA complexes and extraction abilities of P507 with the three RE(Ⅲ)*** dissociation rate is dependent on the stabilities of RE(Ⅲ)-DTPA complexes and follows the sequence ofY(Ⅲ)—DTPA Er>Y to Tm>Y>Er.

关键词： DTPA Interface interaction Non-equilibrium kinetic separation Rare earths P507

Core shift limitation in investment casting process of hollow turbine blade

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Chinese Journal of Aeronautics 2024年第8期37卷 513-526页

作者： Kang cui Lin JING Ruisong JIANG Longnv YU Xiao GAO Automation and Software Engineering Shanxi UniversityTaiyuan 030006China Key Laboratory of High Performance Manufacturing for Aero Engine Ministry of Industry and Information TechnologySchool of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China School of Mechanical Engineering Sichuan UniversityChengdu 610065China

The deviation in wall thickness caused by core shift during the investment casting process significantly impacts the strength and service life of hollow turbine *** address this issue,a core shift limitation method is developed in this ***,a shift model is established based on computational fluid dynamics and motion simulation to predict the movement of the ceramic core in investment casting ***,utilizing this model,an optimization method for fixturing layout inside the refractory ceramic shell is devised for the ceramic *** casting experiment demonstrates that by utilizing the optimized fixture layout,not only can core shift during the investment casting pouring process be effectively controlled,but also the maximum wall thickness error of the blade can be reduced by 42.02%.In addition,the core shift prediction is also validated,with a prediction error of less than 26.9%.

关键词： Hollow turbine blade Wall thickness Ceramic core Shift prediction Fixturing layout optimization

IoV environment exploring coordination:A federated learning approach

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Digital Communications and Networks 2024年第1期10卷 135-141页

作者： Tong Ding Lei Liu Yi Zhu Lizhen cui Zhongmin Yan School of Software Shandong UniversityJinan250101China

Exploring open fields with coordinated unmanned vehicles is popular in academia and *** of the most impressive applicable approaches is the Internet of Vehicles(lov).The IoV connects vehicles,road infrastructures and communication facilities to provide solutions for exploration ***,the coordination of acquiring information from multi-vehicles may risk data *** this end,sharing high-quality experiences instead of raw data has become an urgent *** paper employs a Deep Reinforcement Learning(DRL)method to enable IoVs to generate training data with prioritized experience and states,which can support the IoV to explore the environment more ***,a Federated Learning(FL)experience sharing model is established to guarantee the vehicles'*** numerical results show that the proposed method presents a better successful sharing rate and a more stable convergence within the comparison of fundamental *** experiments also suggest that the proposed method could support agents without full information to achieve the tasks.

关键词： Internet of vehicle Deep reinforcement learning Federated learning Data privacy

Multiscale analysis-based peridynamic simulation of fracture in porous media

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 1-13页

作者： Zihao YANG Shangkun SHEN Xiaofei GUAN Xindang HE Junzhi cui School of Mathematics and Statistics Northwestern Polytechnical UniversityXi’an 710072China School of Mathematical Sciences Tongji UniversityShanghai 200092China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China LSEC ICMSECAcademy of Mathematics and Systems ScienceCASBeijing 100190China

The simulation of fracture in large-scale structures made of porous media remains a challenging *** techniques either assume a homogeneous model,disregarding the microstructure characteristics,or adopt a micro-mechanical model,which incurs an intractable computational cost due to its complex stochastic geometry and physical properties,as well as its nonlinear and multiscale *** this study,we propose a multiscale analysis-based dual-variable-horizon peridynamics(PD)model to efficiently simulate macroscopic structural *** influence of microstructures in porous media on macroscopic structural failure is represented by two PD parameters:the equivalent critical stretch and *** equivalent critical stretch is calculated using the microscale PD model,while the equivalent micro-modulus is obtained through the homogenization method and energy density equivalence between classical continuum mechanics and PD *** examples of porous media with various microstructures demonstrate the validity,accuracy,and efficiency of the proposed method.

关键词： porous media multiscale variable-horizon peridynamic equivalent critical stretch equivalent micro-modulus

Flame Morphology and Characteristic of Co-Firing Ammonia with Pulverized Coal on a Flat Flame Burner

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Journal of Thermal Science 2024年第5期33卷 1935-1945页

作者： WANG Shengye cui Mingshuang LIU Pengzhong DI Yi NIU Fang China Coal Research Institute Beijing 100013China Beijing Tiandi Rongchuang Technology Co.Ltd. Beijing 100013China National Energy Technology&Equipment Laboratory of Coal Utilization and Emission Control Beijing 100013China

Ammonia as a new green carbon free fuel co-combustion with coal can effectively reduce CO_(2)emission,but the research of flame morphology and characteristics of ammonia-coal co-combustion are not *** this work,we studied the co-combustion flame of NH_(3)and pulverized coal on flat flame burner under different oxygen mole fraction(X_(i,O_(2)))and NH_(3)co-firing energy ratios(E_(NH_(3))).We initially observed that the introduction of ammonia resulted in stratification within the ammonia-coal co-combustion flame,featuring a transparent flame at the root identified as the ammonia combustion *** to challenges in visually observing the ignition of coal particles in the ammonia-coal co-combustion flame,we utilized Matlab software to analyze flame images across varying E_(NH_(3))and X_(i,O_(2)).The analysis indicates that,compared to pure coal combustion,the addition of ammonia advances the ignition delay time by 4.21 ms to 5.94 *** E_(NH_(3))increases,the ignition delay time initially decreases and then ***,an increase in X_(i,O_(2))results in an earlier ignition delay *** burn-off time and the flame divergence angle of pulverized coal demonstrated linear decreases and increases,respectively,with the growing ammonia *** addition of ammonia facilitates the release of volatile matter from coal ***,in high-ammonia environments,oxygen consumption also impedes the surface reaction of coal ***,measurements of gas composition in the ammonia-coal flame flow field unveiled that the generated water-rich atmosphere intensified coal particle gasification,resulting in an elevated concentration of ***,nitrogen-containing substances and coke produced during coal particle gasification underwent reduction reactions with NO_(x),leading to reduced NO_(x)emissions.

关键词： co-firing ammonia with coal flame characteristic gas component ignition delay time burn-off time flame divergence angle flat flame burner flame morphology

A Piezoelectrically Driven Microrobot Using a Novel Monolithic Spatial Parallel Mechanism as Its Hip Joint

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Journal of Bionic Engineering 2024年第2期21卷 803-820页

作者： Guangping Wu Ziyang Wang Jiaxin Zhao Feng cui Xinghan Cai National Key Laboratory of Advanced Micro and Nano Manufacture Technology Shanghai Jiao Tong UniversityShanghai200240China Department of Micro-Nano Electronics School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai200240China

Inspired by the fast,agile movements of insects,we present a 1.9 g,4.5 cm in length,piezoelectrically driven,quadrupedal *** microrobot uses a novel spatial parallel mechanism as its hip joint,which consists of two spatially orthogonal slider-crank *** mechanism maps two inputs of two independent actuators to the decoupled swing and lift outputs of a leg,and each leg can produce the closed trajectories in the sagittal plane necessary for robot ***,the kinematics of the transmission are analyzed,and the parameters of the flexure hinges are designed based on geometrical constraints and yield *** hip joints,legs and exoskeletons are integrated into a five-layer standard laminate for monolithic fabrication which is composed of two layers of carbon fiber,two layers of acrylic adhesive and a polyimide *** measured output force(15.97 mN)of each leg is enough to carry half of the robot’s weight,which is necessary for the robot to move *** has been proven that the robot can successfully perform forward and turning *** to the microrobot fabricated with discrete components,the monolithically fabricated microrobot is more capable of maintaining the original direction of locomotion when driven by a forward signal and has a greater speed,whose maximum speed is 25.05 cm/s.

关键词： Insect-like Crawling microrobot Piezoelectric drive Parallel mechanism Monolithic fabrication

Scuffing failure analysis based on a multiphysics coupling model and experimental verification

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Friction 2024年第6期12卷 1214-1234页

作者： Bugao LYU Xianghui MENG Jiabao YIN Yi cui Chengen WANG School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

General reductions in lubricant viscosities and increasing loads in machine components highlight the role of tribofilms in providing surface protection against ***,the relationship between the scuffing process and the growth and removal of tribofilm is not well *** this study,a multiphysics coupling model,which includes hydrodynamic lubrication,asperity contact,thermal effect,tribochemistry reaction,friction,and surface wear,was developed to capture the initiation of surface *** and experiments for a piston ring and cylinder liner contact were conducted following a step-load sequence under different temperature *** results show that high temperature and extreme load could induce the lubricant film collapse,which in turn triggers the breakdown of the tribofilm due to the significantly increased removal *** failures of both lubricant film and tribofilm progress instantaneously in a coupling way,which finally leads to severe scuffing.

关键词： scuffing failure tribofilm boundary lubrication multiphysics coupling effects

Dynamic Characteristics of Functionally Graded Timoshenko Beams by Improved Differential Quadrature Method

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 1647-1668页

作者： Xiaojun Huang Liaojun Zhang Hanbo cui Gaoxing Hu School of Architecture and Civil Engineering Anhui Polytechnic UniversityWuhu241000China College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China

This study proposes an effective method to enhance the accuracy of the Differential Quadrature Method(DQM)for calculating the dynamic characteristics of functionally graded beams by improving the form of discrete node ***,based on the first-order shear deformation theory,the governing equation of free vibration of a functionally graded beam is transformed into the eigenvalue problem of ordinary differential equations with respect to beam axial displacement,transverse displacement,and cross-sectional rotation angle by considering the effects of shear deformation and rotational inertia of the beam ***,ignoring the shear deformation of the beam section and only considering the effect of the rotational inertia of the section,the governing equation of the beam is transformed into the eigenvalue problem of ordinary differential equations with respect to beam transverse *** on the differential quadrature method theory,the eigenvalue problem of ordinary differential equations is transformed into the eigenvalue problem of standard generalized algebraic ***,the first several natural frequencies of the beam can be *** feasibility and accuracy of the improved DQM are verified using the finite element method(FEM)and combined with the results of relevant literature.

关键词： Timoshenko beams functionally graded materials dynamic characteristics natural frequency improved differential quadrature method

Hot-exciton effects on exciton diffusion and circular polarization dynamics in a single PbI_(2)nanoflake

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Science China(Technological Sciences) 2024年第1期67卷 83-90页

作者： XU ChenYu WANG Lei cui Lin GAO BingRong WANG HaiYu State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

As one of the emerging two-dimensional lead halide materials,lead iodide(PbI_(2))nanosheets have proven to possess strong application potential in the fields of high-energy radiation detection and highly efficient perovskite solar ***,the underlying photophysical properties such as hot-exciton-related carrier dynamics remain unclear for PbI_(2)***,we report the exciton dynamics of a single PbI_(2)nanoflake prepared by an aqueous solution *** a three-dimensional(3D)diffusion model,we obtain the exciton annihilation radius and diffusion coefficient of a single PbI_(2)nanoflake under nonresonant and resonant excitation conditions of band-edge exciton *** initial exciton densities increase,we find the carrier recombination mechanism for a single PbI_(2)nanoflake gradually changes from exciton-exciton annihilation to free-carrier ***,we reveal the room-temperature circular polarization of a single PbI_(2)nanoflake is due to free-carrier recombination with a band-edge exciton dissociation time of~120 fs under the resonant excitation condition.

关键词： single PbI_(2)nanoflake exciton diffusion room-temperature circular polarization ultrafast spectroscopy