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Influence of a multi-step process on the thickness reduction error of sheet metal in a flexible rolling process

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International Journal of Minerals,Metallurgy and Materials 2019年第1期26卷 76-85页

作者： Yi Li ming-zhe Li Kai Liu Dieless Forming Technology Center Roll Forging Institute Jilin University College of Materials Science and Engineering Jilin University

Flexible rolling is a forming process based on thickness reduction, and the precision of thickness reduction is the key factor affecting bending deformation. The major purpose of the present work is to solve the problem of bending deformation error caused by insufficient thickness reduction. Under the condition of different rolling reductions with the same sheet thickness and the same thickness reduction with different sheet thicknesses, the thickness reduction error of sheet metal is analyzed. In addition, the bending deformation of sheet metal under the same conditions is discussed and the influence of the multi-step forming process on the thickness reduction error is studied. The results show that, under the condition of the same sheet thickness, the thickness reduction error increases with increasing rolling reduction because of an increase in work hardening. As rolling reduction increases, the longitudinal bending deformation decreases because of the decrease of the maximum thickness difference. Under the condition with the same thickness reduction, the thickness reduction error increases because of the decrease of the rolling force with increasing sheet thickness. As the sheet thickness increases, the longitudinal bending deformation increases because of the increase in the maximum thickness difference. A larger bending deformation is divided into a number of small bending deformations in a multi-step forming process, avoiding a sharp increase in the degree of work hardening; the thickness reduction error is effectively reduced in the multi-step forming process. Numerical simulation results agree with the results of the forming experiments.

关键词： flexible rolling convex surface numerical simulation thickness reduction error multi-step forming process

Can molecular ferroelectrics challenge pure inorganic ones?

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National Science Review 2014年第1期1卷 25-26页

作者： zhe-ming Wang Song Gao Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular Engineering Peking University

Molecular materials have atracted much atention due to their advantages of easy modiication and fabrication,environmentally friendly and less energy-cost processing,transparent,light weight,mechanical lexibility and possible multi-functionalities,compared to their counter parts of pure inorganic or metallic ones,and many functionalities and properties have been discovered and realized in molecule-based materials[1–4].Ferroelectrics,as an important class of multifunctional

关键词： Can molecular ferroelectrics challenge pure inorganic ones high BTO

Improving effect on forming quality and accuracy using a polyurethane board positioning/resetting the discrete steel pad in multi-point forming

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International Journal of Minerals,Metallurgy and Materials 2019年第4期26卷 447-459页

作者： Er-hu Qu ming-zhe Li Rui Li College of Materials Science and Engineering Jilin University Roll Forging Institute Jilin University Changchun Ruiguang Technology Co. Ltd.

To improve the quality of multi-point die forming, a new approach using discrete steel pads was proposed. The formability of three different multi-point die forming processes was analyzed through numerical simulation and experiments. Numerical simulation and experimental results showed that the use of discrete steel pads in the multi-point forming process can substantially improve the stress–strain state on the plate and suppress dimple, straight-edge, and wrinkle defects. This analysis verified that the use of discrete steel pads in a multi-point forming process can effectively improve the quality and accuracy with which sheet metal is formed.

关键词： multi-point forming dimple wrinkle numerical simulation forming accuracy

AN ASYMPTOTICAL O((k + 1)n^3L) AFFINE SCALING ALGORITHM FOR THE P_*(k)-MATRIX LINEAR COMPLEMENTRITY PROBLEM

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Journal of Computational Mathematics 2001年第2期19卷 177-186页

作者： zhe-ming Wang zheng-hai Huang Kun-ping Zhou Department of Statistics and Operations Research Fadan UniversityShanghai 200433China Institute of Applied Mathematics Academy of Mathematics and Systems SciencesAcademy of SciencesBeijing 100080China

Based on the generalized Dikin-type direction proposed by Jansen et al in 1997, we give out in this paper a generalized Dikin-type affine scaling algorithm for solving the P-*(kappa)-matrix linear complementarity problem (LCP). Form using high-order correctors technique and rank-one updating, the iteration complexity and the total computational turn out asymptotically O((kappa + 1)root nL) and O((kappa + 1)n(3)L) respectively.

关键词： linear complementarity problem P*(k)-matrix affine scaling algorithm

Microstructure,Texture Evolution,and Mechanical Properties of ECAP-Processed ZAT522 Magnesium Alloy

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Acta Metallurgica Sinica(English Letters) 2020年第2期33卷 233-242页

作者： Ying Ma Fu-Yin Han Cheng Liu ming-zhe Li School of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Shanxi Key Laboratory of Advanced Magnesium-Based Materials Taiyuan University of TechnologyTaiyuan 030024China

In this work,the high-strength Mg-5Zn-2Al-2Sn(ZAT522,in wt%) Mg alloys was obtained at 220℃ and 130℃ by a two-step equal channel angular pressing(ECAP).For each stage,two passes were *** results showed a remarkable grain refinement after the first stage of ECAP(A2 samples),leading to a fine-grained structure with average size of 1.40 μ*** additional stage(A4 samples) caused further grain refinement to 1.18 μm,and an ultra-fine grain structure(700 nm)appeared in the precipitate-rich *** grain refinement mechanism for both samples was discussed in *** this end,the original extrusion fiber texture evolved into a new strong texture characterized by the base planes tilted toward the ECAP shear plane,with a higher Schmid factor value of *** with the as-extruded alloy,the yield strength of the A2 samples increased from 180 to 245 MPa,which was mainly attributed to the combined effects of grain boundary strengthening and precipitation *** the case of A4 samples,the dislocation strengthening resulted in a net increase in yield strength to 335 MPa,while the ductility was significantly reduced.

关键词： Mg–5Zn–2Al–2Sn Mg alloy ECAP Microstructure Texture Tension properties

Adaptive Dynamic Surface Control for Integrated Missile Guidance and Autopilot

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International Journal of Automation and computing 2011年第1期8卷 122-127页

作者： ming-zhe Hou Guang-Ren Duan Center for Control Theory and Guidance Technology Harbin Institute of Technology Harbin 150001 PRC

Integrated guidance and control for homing missiles utilizing adaptive dynamic surface control approach is considered based on the three channels independence design idea. A time-varying integrated guidance and control model with unmatched uncertainties is first formulated for the pitch channel, and an adaptive dynamic surface control algorithm is further developed to deal with these unmatched uncertainties. It is proved that the proposed feedback controller can ensure not only the accuracy of target interception, but also the stability of the missile dynamics. Then, the same control approach is further applied to the control design of the yaw and roll channels. The 6-degree-of-freedom （6-DOF） nonlinear missile simulation results demonstrate the feasibility and advantage of the proposed integrated guidance and control design scheme.

关键词： Integrated guidance and control unmatched uncertainty adaptive control dynamic surface control homing missiles.

Influence of substrate metals on the crystal growth of AlN films

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International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 98-103页

作者： Juan Xiong Hao-shuang Gu Kuan Hu ming-zhe Hu School of Physics and Electronic Technology Hubei University Wuhan 430062 China

AlN films were deposited by reactive radio frequency （RF） sputtering on various bottom electrodes, such as Al, Ti, Mo, Au/Ti, and Pt/Ti. The effects of substrate metals on the orientation of AlN thin films were investigated. The results of X-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy show that the orientation of AlN films depends on the kinds of substrate metals evidently. The differences of AlN films deposited on various metal electrodes are attributed to the differences in lattice mismatch and thermal expansion coefficient between the AlN material and substrate metals. The AlN film deposited on the Pt/Ti electrode reveals highly the c-axis orientation with well-textured columnar structure. The positive role of the Pt/Ti electrode in achieving the high-quality AlN films and high-performance film bulk acoustic resonator （FBAR） may be attributed to the smaller lattice mismatch as well as the similarity of thermal expansion coefficient between the deposited AlN material and the Pt/Ti electrode substrate.

关键词： AlN films substrate orientation crystallinity

Analysis of imbibition of n-alkanes in kerogen slits by molecular dynamics simulation for characterization of shale oil rocks

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Petroleum Science 2022年第3期19卷 1236-1249页

作者： Qian Sang Xin-Yi Zhao Hui-Min Liu ming-zhe Dong Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao266580ShandongChina School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Management Center of Oil&Gas Exploration of Shengli Oilfield Branch Company SINOPECDongying257001ShandongChina Department of Chemical and Petroleum Engineering University of CalgaryCalgaryABCanadaT2N 1N4

Shale oil formations contain both inorganic and organic *** organic matter holds both free oil in the pores and dissolved oil within the kerogen *** free oil flow in organic pores and the dissolved oil diffusion in kerogen molecules are coupled *** molecular flow of free n-alkanes is an important process of shale oil accumulation and *** study the dynamics of imbibition process of n-alkane molecules into kerogen slits,molecular dynamics(MD)simulations are *** of slit width,temperature,and n-alkane types on the penetration speed,dynamic contact angle,and molecular conformations were *** showed that molecular transportation of n-alkanes is dominated by molecular structure and molecular motion at this *** space-confinement conformational changes of molecules slow down the filling speeds in the narrow *** n-alkane molecules with long carbon chains require more time to undergo conformational *** high content of short-chain alkanes and high temperature facilitate the flow of alkane mixtures in kerogen *** obtained from this study are useful for understanding the underlying nanoscale flow mechanism in shale formations.

关键词： Molecular flow Imbibition n-Alkane Kerogen slit Molecular dynamics simulation

Fluoride-assisted synthesis of anatase TiO_2 nanocrystals with tunable shape and band gap via a solvothermal approach

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Chinese Chemical Letters 2016年第12期27卷 1801-1804页

作者： zhe-ming Liu Lan Peng Ai-Wei Tang Department of Chemistry School of Science Beijing Jiaotong University

A simple solvothermal approach employing oleic acid has been developed to prepare anatase TiO2 nanocrystals with different shapes, which were tuned from nanorods to nano-ellipsoids by increasing the amount of NaF from 0 to 0.5 retool, and the optical band gap decreased from 3.47 eV to 3.29 eV accordingly. However, when the fluoride was changed to NH4F, the resultant TiO2 nanocrystals possessed an anatase phase but were made up of smaller-sized nanocrystals and nanorods, and the band gap was increased to 3.53 eV. The X-ray photoelectron spectroscopy （XPS） results illustrated an increase of fluorine content with an increasing amount of NaF could account for the variation of the shape and optical band gap of TiO2 nanocrystals. Moreover, the absence of fluorine content brought about less change of shape and increase of optical band gap of the product synthesized in the presence of NH4F. This result may offer another way to alter the shape and band gap of metal oxide nanocrystals with the assistance of fluoride.

关键词： Anatase TiO2 Fluoride Synthesis Optical band gap Solvothermal approach