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Adaptive partitioning-based discrete unified gas kinetic scheme for flows in all flow regimes

Advances in Aerodynamics 2023年第1期5卷 282-311页

作者： L.M.Yang L.C.han h.Ding z.h.li C.Shu Y.Y.liu Department of Aerodynamics College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Modern Mechanics University of Science and Technology of ChinaHefei 230027China National Laboratory for Computational Fluid Dynamics Beihang UniversityBeijing 100191China Department of Mechanical Engineering National University of SingaporeSingapore 117576Singapore

To improve the efficiency of the discrete unified gas kinetic scheme(DUGKS)in capturing cross-scale flow physics,an adaptive partitioning-based discrete unified gas kinetic scheme(ADUGKS)is developed in this *** ADUGKS is designed from the discrete characteristic solution to the Boltzmann-BGK equation,which contains the initial distribution function and the local equilibrium *** initial distribution function contributes to the calculation of free streaming fluxes and the local equilibrium state contributes to the calculation of equilibrium *** the contribution of the initial distribution function is negative,the local flow field can be regarded as the continuous flow and the Navier-Stokes(N-S)equations can be used to obtain the solution ***,the discrete distribution functions should be updated by the Boltzmann equation to capture the rarefaction *** this,in the ADUGKS,the computational domain is divided into the DUGKS cell and the N-S cell based on the contribu-tion of the initial distribution function to the calculation of free streaming *** the N-S cell,the local flow field is evolved by solving the N-S equations,while in the DUGKS cell,both the discrete velocity Boltzmann equation and the correspond-ing macroscopic governing equations are solved by a modified *** more and more cells turn into the N-S cell with the decrease of the Knudsen number,a significant acceleration can be achieved for the ADUGKS in the continuum flow regime as compared with the DUGKS.

关键词： Boltzmann-BGK equation Discrete unified gas kinetic scheme Adaptive partitioning Discrete characteristic solution All flow regimes

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Numerical performance assessment of double-shell targets for z-pinch dynamic hohlraum

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Matter and Radiation at Extremes 2022年第3期7卷 10-19页

作者： Y.Y.Chu z.Wang J.M.Qi z.P.Xu z.h.li Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China

A z-pinch dynamic hohlraum can create the high-temperature radiation field required by indirect-drive inertial confinement fusion.A dynamic hohlraum with peak radiation temperature over 300 eV can be obtained with a>50 MA z-pinch driver according to the scaling law of dynamic hohlraum radiation temperature vs drive *** on a uniform 300 eV radiation temperature profile with a width of 10 ns,three double-shell capsules with radii of 2,2.5,and 3 mm are proposed,and the corresponding fusion yields from a one-dimensional calculation are 28.8,56.1,and 101.6 *** implosion dynamics of the 2.5 mm-radius capsule is investigated in *** ignition,the areal density of the fuel is about 0.53 g/cm^(2),the fuel pressure is about 80 Gbar,and the central ion temperature is about 4.5 keV,according to the one-dimensional simulation.A two-dimensional simulation indicates that the double-shell capsule can implode nearly spherically when driven by the radiation field of a z-pinch dynamic *** sensitivities of the fusion performance to the radiation temperature profiles and to deviations in the capsule parameter are investigated through one-dimensional simulation,and it is found that the capsule fusion yields are rather stable in a quite large parameter space.A one-dimensional simulation of a capsule embedded in 50 mg/cm^(3)Ch foam indicates that the capsule performance does not change greatly in the mimicked environment of a z-pinch dynamic *** double-shell capsules designed here are also applicable to laser indirect-drive inertial fusion,if a laser facility can produce a uniform 300 eV radiation field and sustain it for about 10 ns.

关键词： dynamic double performance

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Development of thermal simulation system for heavy section ductile iron solidification

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China Foundry 2004年第S1期1卷 25-28页

作者： z.h.li h.Y.Geng Y.X.li Department of Mechanical Engineering Tsinghua UniversityBeijing 100084P.R.China

A new reliable thermal simulation system for studying solidification of heavy section ductile iron has been developed using computer feedback control and artificial intelligent methods. Results of idle test indicate that the temperature in the system responses exactly to the inputted control data and the temperature control error is less than ±0.5%. It is convenient to simulate solidification of heavy section ductile iron using this new system. Results of thermal simulation experiments show that the differences in nodularity and number of graphite nodule per unit area in the thermal simulation specimen and the actual heavy section block is less than 5% and 10%, respectively.

关键词： solidification thermal simulation heavy section ductile iron

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PLASMA SURFACE ALLOYING OF AGE-hIGh SPEED STEEL

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 836-840页

作者： z.h.li,X.P.liu,Y.Gao and z.Xu Research Institute of Surface Engineering, Taiyuan University of Technology,Taiyuan 030024, China

It, ageing high speed steel (AhSS) with high cobalt, has a strong ability of age hardening. however, it has two disadvantages, One is short of toughness, the other is its high price because of its too much alloy content especially cobalt. All of these effect on its widespread using. Now there is a new method without the two flows to form this steel in the surface of ingot iron by use of double glow plasma surface alloying *** this paper, the following three parts are introduced: the metallurgical process of this surface ageing high speed steel (SAhSS), the micro structure of the alloying layer, the alloy distribution in the layer. By using the designed source pole, the special alloying process, the required surface alloying content, just like the AhSS—Co23W11Mo7 can be achieved in the surface layer. This new method has wide prospect in the fields of tools, moulds and other wear resisting fields.

关键词： SAhSS metallurgical process age hardening

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A Novel Micro-porous Polymer Electrolyte Comprising SnO_2 Nanorods and P(MMA-AN)

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复旦学报（自然科学版） 2007年第5期46卷 848-页

作者： P.zhang h.P.zhang z.h.li Y.P.Wu Department of Chemistry & Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan University

1 Results Micro-porous polymer electrolytes(MPEs), which almost obtained by the conventional methods of phase inversion process or immersion precipitation method, have significant advantages such as high ionic conductivity and excellent mechanical properties[1].In our work, micro-porous structure is obtained by adding SnO2 nanorods usually used as gas senor materials into the polymer matrix, which proves a new way to prepare ***2 nanorods were synthesized by microemulsion hydrothermal method[2]. Th...

关键词： micro-porous polymer electrolyte SnO2 nanorods P(MMA-AN)

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A negative deviation from Porod’s law in SAXS of organo—MSU—X

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Beijing Synchrotron Radiation Facility 2001年第2期 20-25页

作者： z.h.li Y.J.Gong D.Wu Y.h.Sun J.Wang Y.liu B.z.Dong Y.J. LaboratoryofSynchrotronRadiation InstituteofHighEnergyPhysicschineseAcademyofSciencesP.O.Box165Beijing100039People’sRepublicofchina StateKeyLaboratoryofCoalConverison InstituteofCoalChemistryChi

Small-angle X-ray scattering(SAXS)using synchrotron radiation as X-ray source has been employed to charactcizc the microscopic structrure of organo-modified mesoporous molecular sieves(organo-MSU-X)prepared by a one-pot template-directed *** is shown that the SAXS profile is hardly constant with Porod’s law showing a negative slope,i.e.,negative *** suggests that there is diffuse interfacial layer located between the pores and the *** suggests that the organic groups remain covalently linked to the matrix,as indicated by ^29SiCP MAS NMR and *** average thickness of the interfacial layer was found to be about 1nm for each of the three samples with different kinds and the same amounts(20? of organic *** kind of material has also been proved to possess both surface and mass fractal structure of the amophous porous silica materials.2001 Elsevier Science *** rights reserved.

关键词：中孔材料 SAXS 小角X射线散射分析界面层结构特征有机中孔分子筛负偏差 Porod法

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Investigation of negative-parity states in ^(16)C via deuteron inelastic scattering

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Chinese Physics C 2022年第5期46卷 70-76页

作者： z.W.Tan J.L.Lou Y.L.Ye Y.liu D.Y.Pang C.X.Yuan J.G.li W.liu Y.Jiang B.Yang L.C.Tao K.Ma z.h.li Q.T.li X.F.Yang J.Y.Xu h.z.Yu J.X.han S.W.Bai S.W.huang G.li h.Y.Wu h.L.zang J.Feng J.S.Wang Y.Y.Yang P.Ma Q.hu z.Bai z.h.Gao F.F.Duan L.Y.hu J.h.Tan S.Q.Sun Y.S.Song h.J.Ong D.T.Tran h.Y.zhu B.L.Xia School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China School of Physics Beijing Key Laboratory of Advanced Nuclear Materials and PhysicsBeihang UniversityBeijing 100191China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering UniversityHarbin 150001China Research Center for Nuclear Physics Osaka universityOsaka 567-0047Japan Institute of Physics Vietnam Academy of Science and TechnologyHanoi 10000Vietnam Institute of Materials China Academy of Engineering PhysicsMianyang 621907China

Two low-lying unbound states in ^(16)C are investigated by deuteron inelastic scattering in inverse *** the 2^(-) state at 5.45 MeV previously measured in a 1n knockout reaction,a new resonant state at 6.89 MeV is observed for the first *** inelastic scattering angular distributions of these two states are well reproduced by the distorted-wave Born approximation(DWBA)calculation with an l=1 *** addition,the spinparities of the unbound states are discussed and tentatively assigned based on shell model calculations using the modified YSOX interaction.

关键词： negative-parity states inelastic scattering ^(16)C

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Targeting epigenetic mechanisms in amyloid-β-mediated Alzheimer’s pathophysiology:unveiling therapeutic potential

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Neural Regeneration Research 2025年第1期20卷 54-66页

作者： Jennie z.li Nagendran Ramalingam Shaomin li Ann Romney Center for Neurologic Diseases Brigham and Women’s Hospital and Harvard Medical SchoolBostonMAUSA

Alzheimer’s disease is a prominent chronic neurodegenerative condition characterized by a gradual decline in memory leading to *** evidence suggests that Alzheimer’s disease is associated with accumulating various amyloid-βoligomers in the brain,influenced by complex genetic and environmental *** memory and cognitive deficits observed during the prodromal and mild cognitive impairment phases of Alzheimer’s disease are believed to primarily result from synaptic *** life,environmental factors can lead to enduring changes in gene expression and the emergence of brain *** changes,known as epigenetic modifications,also play a crucial role in regulating the formation of synapses and their adaptability in response to neuronal *** this context,we highlight recent advances in understanding the roles played by key components of the epigenetic machinery,specifically DNA methylation,histone modification,and microRNAs,in the development of Alzheimer’s disease,synaptic function,and activity-dependent synaptic ***,we explore various strategies,including enriched environments,exposure to non-invasive brain stimulation,and the use of pharmacological agents,aimed at improving synaptic function and enhancing long-term potentiation,a process integral to epigenetic ***,we deliberate on the development of effective epigenetic agents and safe therapeutic approaches for managing Alzheimer’s *** suggest that addressing Alzheimer’s disease may require distinct tailored epigenetic drugs targeting different disease stages or pathways rather than relying on a single drug.

关键词： Alzheimer’s disease DNA methylation enriched environments histone modification microRNAs non-invasive brain stimulation synaptic plasticity

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Study of the structure and the reaction of the light neutron rich nuclei at Peking University

Study of the structure and the reaction of the light neutron...

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2005年全国核反应会议

作者： Y.L.Ye, D.X.Jiang, T.zheng, z.h.li, h.hua X.Q.li, D.Y.Pang, GL.zhang, J.Wang,C.Wu, z.Q.Chen, Q.Y.hu, Y.C.Ge, J.L.Lou, F.Lu, F.Y.Fan Department of Technical Physics and the DOE Key laboratory of heavy Ion Physics, School of Physics, Peking University, Beijing, 100871, China

Firstly the structure of the lightest neutron rich halo nucleus 6he has been studied via the direct nuclear reaction such as quasi-elastic scattering, breakup reaction and transfer reactions. The experiment was performed at RIKEN-RIBS beam line. Clear particle identification for isotopes of z=1 to z=4 were obtained by the telescopes, corresponding to various reaction

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Prediction of velocity and pressure of gas-liquid flow using spectrum-based physics-informed neural networks

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Applied Mathematics and Mechanics(English Edition) 2025年第2期46卷 341-356页

作者： Nanxi DING hengzhen FENG h.z. LOU Shenghua FU Chenglong li zihao zhANG Wenlong MA zhengqian zhANG School of Mechanical Engineering Beijing Institute of Technology University of Southern California Xi'an Institute of Electromechanical Information Technology

This research introduces a spectrum-based physics-informed neural network (SP-PINN) model to significantly improve the accuracy of calculation of two-phase flow parameters, surpassing existing methods that have limitations in global and continuous data sampling. SP-PINNs address the challenges of traditional methods in terms of continuous sampling by integrating the spectral analysis and pressure correction into the Navier-Stokes (N-S) equations, enhancing the predictive accuracy especially in critical regions like gas-phase boundaries and velocity peaks. The novel introduction of a pressure-correction module within SP-PINNs mitigates prediction errors, achieving a substantial reduction to 1‰compared with the conventional physics-informed neural network (PINN) approaches. Experimental applications validate the model’s ability to accurately and rapidly predict flow parameters with different sampling time intervals,with the computation time of predicting unsampled data less than 0.01 s. Such advancements signify a 100-fold improvement over traditional DNS calculations, underscoring the model’s potential in the real-time calculation and analysis of multiphase flow dynamics.

关键词： physics-informed neural network (PINN) spectral method two-phase flow parameter prediction O359

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