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Flow stress model considering the transformation-induced plasticity effect and the inelastic strain recovery behavior

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International Journal of Minerals,Metallurgy and Materials 2011年第2期18卷 185-191页

作者： Hai-yan Yu Li bao School of Automotive Engineering Tongji University Shanghai 200092 China

On the basis of continuum mechanics and the Mori-Tanaka mean field theory, a micro-mechanical flow stress model that considered both the transformation-induced plasticity （TRIP） effect and the inelastic strain recovery behavior of TRIP multiphase steels was presented. The relation between the volume fraction of constituent phases and plastic strain was introduced to characterize the transformation-induced plasticity effect of TRIP steels. Loading-unloading-reloading uniaxial tension tests of TRIP600 steel were carried out and the strain recovery behavior after unloading was analyzed. From the experimental data, an empirical elastic modulus expression is extracted to characterize the inelastic strain recovery. A comparison of the predicted flow stress with the experimental data shows a good agreement. The mechanism of the transformation-induced plasticity effect and the inelastic recovery effect acting on the flow stress is also discussed in detail.

关键词： flow stress transformation-induced plasticity inelastic strain elastic modulus

Source and Control of Nitrogen for X70 Pipeline Steel

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Journal of Iron and Steel Research International 2016年第7期23卷 647-654页

作者： Min WANG yan-ping bao State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The effects of some key factors on nitrogen absorption during the smelting process of X70 pipeline steel were studied,and the source of nitrogen pick-up was analyzed to find the bottleneck for nitrogen control.A series of measures were put forward to decrease the nitrogen *** results indicated that an exponential relationship existed between the nitrogen absorption index and the free oxygen in molten *** absorption index could decrease below 0.3when free oxygen in molten steel was above 100×10^（-6） after *** low sulfur killed steel,the nitrogen absorption ratio and sulfur content satisfied a linear relationship with a slope *** free-oxygen and sulfur were beneficial to the deep desulfurization during vacuum *** contradiction of high desulfurization ratio and low nitrogen pick-up during LF process could be resolved by skimming oxidizing slag after tapping and making new high basicity top *** optimization,the average content of nitrogen in final product decreased from 46×10（-6）to 35×10（-6）.

关键词： nitrogen control nitrogen absorption surface activity element X70 pipeline steel

Mn evaporation and denitrification behaviors of molten Mn steel in the vacuum refining with slag process

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International Journal of Minerals,Metallurgy and Materials 2021年第8期28卷 1288-1297页

作者： Jian-hua Chu yan-ping bao State Key Lab of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

Considering the precise composition control on the vacuum refining of high-Mn steel, the behaviors of both Mn evaporation and nitrogen removal from molten Mn steel were investigated via vacuum slag refining in a vacuum induction furnace. It was found that the reaction interfaces of denitrification and Mn evaporation tend to migrate from the surface of slag layer to the surface of molten steel with the gradual exposure of molten steel during the vacuum slag refining process. Significantly, compared with the experimental group without slag addition, the addition of slag into steel can result in a lower Mn evaporation rate constant of 0.0192 cm·min~(-1) at 370 Pa, while the denitrification rate is almost not affected. Besides, the slag has a stronger inhibitory effect on Mn evaporation than the reduced vacuum pressure. Moreover, the inhibitory effect of the slag layer on Mn evaporation can be weakened with the increase of the initial Mn content in molten steel. The slag layer can work as an inhibitory layer to reduce the Mn evaporation from molten steel, the evaporation reaction of Mn mainly proceeds on the surface of the molten steel. This may be attributed to the Mn mass transfer coefficient for one of reaction at steel/slag interface, mass transfer in molten slag, and evaporation reaction at slag/gas interface is lower than that of evaporation reaction at steel/gas interface. The introduction of slag is proposed for both denitrification and manganese control during the vacuum refining process of Mn steels.

关键词： manganese evaporation denitrification vacuum slag evaporation rate

Cohomology structure for a Poisson algebra:Ⅱ

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Science China Mathematics 2021年第5期64卷 903-920页

作者： yan-Hong bao Yu Ye School of Mathematical Sciences Anhui UniversityHefei 230601China School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China Wu Wen-Tsun Key Laboratory of Mathematics USTCChinese Academy of SciencesHefei 230026China

For a Poisson algebra,we prove that the Poisson cohomology theory introduced by Flato et al.(1995)is given by a certain derived *** show that the(generalized)deformation quantization is equivalent to the formal deformation for Poisson algebras under certain mild *** we construct a long exact sequence,and use it to calculate the Poisson cohomology groups via the Yoneda-extension groups of certain quasi-Poisson modules and the Lie algebra cohomology groups.

关键词： Poisson algebra Poisson cohomology formal deformation deformation quantization

A semi-implicit three-step method based on SUPG finite element formulation for flow in lid driven cavities with different geometries

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第1期12卷 33-45页

作者： Cheng HUAN Dai ZHOU yan bao School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China

A numerical algorithm using a bilinear or linear finite element and semi-implicit three-step method is presented for the analysis of incompressible viscous fluid problems. The streamline upwind/Petrov-Galerkin (SUPG) stabilization scheme is used for the formulation of the Navier-Stokes equations. For the spatial discretization, the convection term is treated explicitly, while the viscous term is treated implicitly, and for the temporal discretization, a three-step method is employed. The present method is applied to simulate the lid driven cavity problems with different geometries at low and high Reynolds numbers. The results compared with other numerical experiments are found to be feasible and satisfactory.

关键词： Semi-implicit three-step method Streamline upwind/Petrov-Galerkin (SUPG) finite element method (FEM) Unsteady incompressible flows Lid driven cavity problem

Editorial for special issue on metallurgical process engineering and intelligent manufacturing

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International Journal of Minerals,Metallurgy and Materials 2021年第8期28卷 1249-1252页

作者： An-jun Xu yan-ping bao School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

In recent years, new concepts and new technologies for improving the manufacturing level have emerged one after another, and the global industrial competition pattern will undergo major adjustments. The United States proposed the"Advanced Manufacturing Country" strategy, France proposed the "New Industry France Plan," and Germany proposed "Industry 4.0." At the same time.

关键词： intelligent pattern emerged

On-line optical determination of floc size of Fe(Ⅲ) coagulants

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Journal of Environmental Sciences 2005年第6期17卷 921-925页

作者： WANG yan GAO bao-yu YUE Qin-yan ZHOU Wei-zhi CHU Yong-bao School of Environmental Science and Engineering Shandong University Jinan 250100 China

This study investigated the floc aggregation, average floc size, floc size variance and floc growth velocity when ferric chloride （FeCl3） and polyferric chloride （PFC） were used to treat the simulated water samples. The factors including coagulant dose, ionic strength and solution pH, which affect the floc aggregation, were studied. Experiments were carried out in a bench-scale reactor using photometric dispersion analyzer （ PDA）. Results showed that there were great differences between the floc aggregation of PFC and FeCl3. The average floc size and fioc growth velocity of PFC were much larger than those of FeCl3. Compared with FeCl3, PFC gave a better coagulation performance in wider range of pH, dosage and ionic strength. It was also found that the coagulation efficiency of PFC did not depend on average floc size but on floc growth velocity.

关键词： coagulants photometric dispersion analyzer(PDA) floc aggregation water treatment

Special Issue on Electromechanical Coupling Design for Electronic Equipment

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 495-496页

作者： bao yan DUAN Jian Rong TAN Key Laboratory of Electronic Equipment Structure Design of Ministry of Education Xidian University State Key Lab of CAD&CG Zhejiang University

With the development of electronic equipment to high accuracy, high density, high frequency, and atrocious ser- vice environment, the functional surface in this type of equipment has increasingly serious problems,

关键词： In Special Issue on Electromechanical Coupling Design for Electronic Equipment Design

Causes for the Unimodal Pattern of Leaf Carbon Isotope Composition in Abies faxoniana Trees Growing in a Natural Forest along an Altitudinal Gradient

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Journal of Mountain Science 2015年第1期12卷 39-48页

作者： ZHAO Hong-xia DUAN bao-li LEI yan-bao Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences

Leaf morphological and physiological traits of Abies faxoniana growing in a natural forest along an altitudinal gradient were measured with the aim to identify the central mechanism for the marked variation in foliar δ13C determined by an isotope ratio mass spectrometer. There is a unimodal pattern of plant functional traits in these temperate and semi- humid areas. Stomatal parameters, specific leaf area, and C/N ratio increased, whereas C, N and δ13C values decreased with increasing altitude below 3000 m a.s.1. In contrast, they exhibited opposite trends above 3000 m a.s.l.. Our results demonstrated that high-altitude plants achieve higher water use efficiency （WUE） at the expense of decreasing nitrogen use efficiency （NUE）, whereas plants at 3000 m can maintain a relatively higher NUE but a lower WUE. Such intra-specific differences in the trade-off between NUE and WUE may partially explain the altitudinal distribution of the plants in relation to moisture and nutrient availability. Our results clearly indicate that the functional relations between nutritional status and the structure of leaves are responsible for the altitudinal variations associated with δ13C. The pivotal role of specific leaf area in regulating plant adaptive responses provides a potential physiological mechanism for the observed growth advantage of populations occupying the medium altitude. These adaptive responses altitudinal gradients showed that an altitude to of approximately 3000 m a.s.1, is the optimum distribution zone for A. faxoniana, allowing the most vigorous growth and metabolism. These results improve our understanding of the various roles of environmental and biotic variables upon δ13C dynamics and provide useful information for subalpine coniferous forest management.

关键词： Abiesfaxoniana Age Altitude Carbonisotope ratio Nitrogen content