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NUMERICAL SIMULATION OF TWO-PHASE GRAVITY CURRENTS OVER A POROUS SUBSTRATE

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Journal of Hydrodynamics 2003年第5期15卷 81-90页

作者： Zhou liang , hu Yue, Zhang hui sheng Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433, China, Department of Mechanics and Engineering Science Fudan University Shanghai 200433 China

Based on shallow-water approximations the governing equations for twodimensional two-phase gravity currents over a porous substrate and some appropriate boundaryconditions were introduced. With on characteristic interpolations the numerical boundary conditionswere introduced and a series of exact solutions were constructed. Numerical a-nalysis were made byusing the two-step Lax scheme, second-order TVD scheme, third-order ENO scheme and fifth-order WE NOscheme combined with second- and third-order TVD-Runge-Kutta method is given. It is found that forpractice applications the second-order TVD scheme combined with the second-order TVD- Runge- Kuttamethod is an economical and suitable choice.

关键词： two-phase gravity currents porous substrate numerical simulation

Effects of temperature-gradient-induced damage of zirconia metering nozzles

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International Journal of Minerals,Metallurgy and Materials 2017年第9期24卷 999-1003页

作者： liang Zhao Qun-hu Xue College of Materials and Mineral Resources Xi’an University of Architecture and TechnologyXi’an 710055China Shaanxi Techno-institute of Recycling Economy Xi’an 710055China

The effects of temperature-gradient-induced damage of zirconia metering nozzles were investigated through analysis of the phase composition and microstructure of nozzle samples. The analysis was carried out using X-ray diffraction and scanning electron microscopy after the samples were subjected to a heat treatment based on the temperatures of the affected, transition, and original layers of zirconia metering nozzles during the continuous casting of steel. The results showed that, after heat treatment at 1540, 1410, or 1300A degrees C for a dwell time of 5 h, the monoclinic zirconia phase was gradually stabilized with increasing heat-treatment temperature. Moreover, a transformation to the cubic zirconia phase occurred, accompanied by grain growth, which illustrates that the temperature gradient in zirconia metering nozzles affects the mineral composition and microstructure of the nozzles and accelerates damage, thereby deteriorating the quality and service life of the nozzles.

关键词： temperature gradient zirconia metering nozzles mineral composition microstructure damage mechanism

Tribological behavior of a Ni-WS2 composite coating across wide temperature ranges

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Rare Metals 2019年第11期38卷 1078-1085页

作者： Shuai Cui Wen-sheng Li Ling He Li Feng Guo-sheng An Wei hu Chun-Xia hu School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China

In order to reduce the friction coefficient of a pure nickel coating and extend the lifetime of metal parts under extreme friction conditions,a series of Ni-based WS2-composite solid lubrication coating containing different WS2 concentrations were prepared on a 45#mild carbon steel substrate by *** cyclic voltammetry method was used to investigate the electroplating regulation of the Ni-WS2 composite coatings.X-ray diffraction(XRD) and scanning electron microscopy(SEM) were used to analyze the microstructures and wear surfaces of the composite coatings,the tribological properties and wear mechanisms of the composite coatings with different WS2 *** results show that the addition of WS2 can promote the cathode polarization of the electroplating process,and the polarization degree goes up with the increase in WS2 *** friction coefficient of Ni-composite coatings significantly decreases by the addition of WS2 *** lowest friction coefficient at room temperature is obtained at a value around 0.01-0.03 from the coating deposited in the electrolyte solution with a 30g·L^-1 WS2 *** friction coefficient of the Ni-WS2 composite coating remains in 0.01-0.03 with the increase in temperature from room temperature to 300℃.When the temperature goes up to 500℃,the friction coefficient manifests a continuous increase to 0.12,because WS2 is gradually oxidized into WO3 and therefore loses its lubrication ability.

关键词： WS2 Self-lubricating composites coating Frictional wear Temperature

Research on swarm intelligence optimization algorithm

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The Journal of China Universities of Posts and Telecommunications 2020年第3期27卷 1-20,30页

作者： Fei Wei Liu Cong hu sheng hubei Key Laboratory for High-Efficiency Utilization of Solar Energy and Operation Control of Energy Storage System Hubei University of TechnologyWuhan 430068China hubei Collaborative Innovation Center for High-Efficiency Utilization of Solar Energy Hubei University of Technologywuhan 430068China Wuhan hua'an Science and Technology Co. Ltd.Postdoctoral WorkstationWuhan 430068.China

The bionics-based swarm intelligence optimization algorithm is a typical natural heuristic algorithm whose goal is to find the global optimal solution of the optimization *** simulates the group behavior of various animals and uses the information exchange and cooperation between individuals to achieve optimal goals through simple and effective interaction with experienced and intelligent *** paper first introduces the principles of various swarm intelligent optimization ***,the typical application of these swarm intelligence optimization algorithms in various fields is *** that,the advantages and defects of all swarm intelligence optimization algorithms are ***,the improvement strategies of various swarm intelligence optimization algorithms are ***,the future development of various swarm intelligence optimization algorithms is prospected.

关键词： bionics natural heuristic algorithm swarm intelligence algorithm intelligent computing

Study on the damage-softening constitutive model of rock and experimental verification

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Acta Mechanica Sinica 2019年第4期35卷 786-798页

作者： sheng-Qi Yang Bo hu Peng Xu State Key Laboratory for Geomechanics and Deep Underground Engineering School of Mechanics and Civil Engineering China University of Mining and Technology Xuzhou 221116 China China Construction Third Engineering Design Bureau Co. Ltd Wuhan 430064 China

A damage-softening model is presented to describe the stress-strain curve of rock. By comparing the Hoek-Brown (H-B) and Mohr-Coulomb (M-C) yield criterion, the equivalent M-C yield criterion is selected as the strength criterion in this model. To better characterize the rock damage and failure processes with considering the relationship between damage and deformation, the concept of yield stress ratio is introduced to describe the yield strengthening deformation before rock peak stress. Damage events are described by two cumulative damage evolution laws. The evolution equations of tensile and shear damage are presented based on the equivalent plastic strains and the maximum value between tensile and shear damage represents the total damage for rock. Considering that rock cannot bear tensile load after tensile failure but still has a certain shear strength, its tensile and shear strengths are small after shear failure. The elastic modulus is affected by tensile damage, whereas the angle of internal friction, the cohesion, and dilation angles are influenced by shear damage. The proposed damage-softening model describes the strain-softening, brittle stress-drop, and residual strength of rock after peak stress, and finally the model is implemented in FLAC3D. Comparing the test and the numerical calculation results, the damage-softening model better describes the total stress-strain curve of rock.

关键词： Rock deformation Damage evolution Softening Numerical calculation

Multi-loop adaptive internal model control based on a dynamic partial least squares model

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第3期12卷 190-200页

作者： Zhao ZHAO Bin hu Jun liang State Key Lab of Industrial Control Technology Department of Control Seienee & Engineering Zhejiang University Hangzhou 310027 China

A multi-loop adaptive internal model control (IMC) strategy based on a dynamic partial least squares (PLS) frame-work is proposed to account for plant model errors caused by slow aging,drift in operational conditions,or environmental *** PLS decomposition structure enables multi-loop controller design within latent spaces,a multivariable adaptive control scheme can be converted easily into several independent univariable control loops in the PLS *** each latent subspace,once the model error exceeds a specific threshold,online adaptation rules are implemented separately to correct the plant model mismatch via a recursive least squares (RLS) *** the IMC extracts the inverse of the minimum part of the internal model as its structure,the IMC controller is self-tuned by explicitly updating the parameters,which are parts of the internal *** parameter convergence and system stability are briefly analyzed,and proved to be ***,the proposed control scheme is tested and evaluated using a widely-used benchmark of a multi-input multi-output (MIMO) system with pure delay.

关键词： Partial least squares (PLS) Adaptive internal model control (IMC) Recursive least squares (RLS)

Applications of chemical imaging techniques in paleontology

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National Science Review 2019年第5期6卷 1040-1053页

作者： Yanhong Pan liang hu Tao Zhao CAS Key Laboratory of Economic Stratigraphy and Palaeogeography Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy of Sciences

Chemical imaging techniques, based on a combination of microscopy and spectroscopy, are designed to analyse the composition and spatial distribution of heterogeneous chemical complexes within a *** the last few decades, it has become an increasingly popular tool for characterizing trace elements,isotopic information and organic biomarkers(molecular biosignatures) found in ***, we introduce the analytical principle of each technique and the interpretation of the chemical signals, followed by a review of the main applications of these techniques in *** also demonstrate that each technique is associated with pros and cons, and the current limitations and obstacles associated with the use of each specific technique should be taken into account before being applied to fossil ***, we propose that, due to the rapid advances in the available technology and overall trends towards more multi-disciplinary studies in paleontology, chemical imaging techniques can be expected to have broader applications in paleontology in the near future.

关键词： trace elements isotopic information organic biomarkers fossil materials limits and obstacles

Recent advances of bismuth-based electrocatalysts for CO_(2)reduction:Strategies,mechanism and applications

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Materials Reports(Energy) 2023年第2期3卷 4-26,I0002页

作者： Xiao-Du liang Na Tian sheng-Nan hu Zhi-You Zhou Shi-Gang Sun State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005PR China

Electrocatalytic CO_(2)reduction reaction(CO_(2)RR),driven by clean electric energy such as solar and wind,can not only alleviate environmental greenhouse effect stemming from excessive CO_(2)emissions,but also realize the storage of renewable energy,for it guarantees the production of value-added chemicals and *** CO_(2)RR products,formic acid shows great advantages in low energy consumption and high added-value,and thus producing formic acid is generally considered as a profitable line for CO_(2)***-based electrocatalysts exhibit high formic acid selectivity in CO_(2)***,we review the recent progress in bismuth-based electrocatalysts for CO_(2)RR,including material synthesis,performance optimization/validation,and *** effects of morphologies,structure,and composition of bismuth-based electrocatalysts on CO_(2)RR performance are ***,in situ spectroscopic characterization and DFT calculations for reaction mechanism of CO_(2)RR on Bi-based catalysts are *** applications and optimization of electrolyzers with high current density for CO_(2)RR are ***,conclusions and future directions in this field are prospected.

关键词： Bismuth-based electrocatalysts Electrochemical CO_(2)reduction reaction Formate Structure-activity relationship Electrolyzer

PROBLEMS OF U-SHAPED BELLOWS WITH NONLINEAR DEFORM TION OF LARGE AXISYMMETRICAL DEFLECTION(Ⅰ)--COUNTING NONLINEAR DEFORMATIONS OF RING SHELLS AND COMPRESSED ANGLE OF BELLOWS

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Applied Mathematics and Mechanics(English Edition) 1993年第3期14卷 253-267页

作者： hu liang Shanghai Institute of Applied Mathematics and Mechanics Shanghai University of Technology Shanghai

This paper follows the work of[1,2].There are some progress in dealing with moderately small rotations(the squares of rotation angles are the order of magnitude of strains)of middle surface normals of inside and outside ring shells and compressed angle of *** results agree with experiments *** bellow design,the method given in this paper is of practical value and the discussion of the influence of compressed angle on characteristic relation is helpful.

关键词： U-shaped bellows large axisymmetrical deflection compressed angle