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Cold compression deformation method for reducing residual stress and uniformizing micro-property in ferrite steel

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Journal of Iron and Steel Research International 2022年第3期29卷 503-511页

作者： bo ning Hui-bin Wu Gang Niu Xin-pan Yu Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing100083China

To reduce internal residual stress and homogenize micro-property of hot-rolled ferrite steel,the cold compression deformation method with small reduction rate has been performed in the hot-rolled samples,and X-ray diffraction and nanoindentation test have been used to detect the residual stress and *** samples with deformation rate of 0-5.59%or annealing at 550℃ are *** results show that,due to the coupling effect of thermal expansion and cold contraction and the volume expansion of microstructural transformation from austenite to ferrite,compressive residual stress was found inside the hot-rolled *** the increase in cold compression deformation,the dislocation density increased and the microhardness increased gradually,and there is no obvious rule for the change of mean nano-hardness in micro-zone for the center of ***,the uniformity of nano-hardness in the micro-zone increased first and then decreased,and the value of residual stress has obvious corresponding relationship with the uniformity of micro-zone *** cold compression deformation with appropriate reduction rate can reduce residual stress and improve nano-hardness uniformity of the hot-rolled samples,but more deformation(such as reduction rateε=5.59%)makes residual stress increase and makes uniformity of nano-hardness deteriorate.

关键词： Ferrite Cold compression deformation Residual stress Nano-hardness Uniformity Dislocation density

Degree Conditions Restricted to Induced Paths for Hamiltonicity of Claw-heavy Graphs

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Acta Mathematica Sinica,English Series 2017年第2期33卷 301-310页

作者： Bin Long LI bo ning Sheng Gui ZHANG Department of Applied Mathematics Northwestern Polytechnical University Xi'an 710072 P. R. China European Centre of Excellence NTIS 30614 Pilsen Czech Republic Center for Applied Mathematics Tianjin University Tianjin 300072 P. R. China

Broersma and Veldman proved that every 2-connected claw-free and P6-free graph is hamil- tonian. Chen et al. extended this result by proving every 2-connected claw-heavy and P6-free graph is hamiltonian. On the other hand, Li et al. constructed a class of 2-connected graphs which are claw-heavy and P6-o-heavy but not hamiltonian. In this paper, we further give some Ore-type degree conditions restricting to induced copies of P6 of a 2-connected claw-heavy graph that can guarantee the graph to be hamiltonian. This improves some previous related results.

关键词： Hamiltonian graph forbidden subgraph condition degree condition claw-heavy graph,closure theory

boundary Conditions for NHEK through Effective Action Approach

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Chinese Physics Letters 2012年第4期29卷 23-26页

作者： CHEN Bin ning bo ZHANG Jia-Ju Department of Physics and State Key Laboratory of Nuclear Physics and TechnologyPeking UniversityBeijing 100871

We study the asymptotic symmetry group (ASG) of the near horizon geometry of extreme Kerr black hole through the effective action approach developed by Porfyriadis and Wilczek (arXiv:1007.1031v1[gr qc]).By requiring a finite boundary effective action,we derive a new set of asymptotic Killing vectors and boundary conditions,which are much more relaxed than the ones proposed by Matsuo Y et al.[***.B 825 (2010) 231],and still allow a copy of a conformal group as its *** the covariant formalism,the asymptotic charges are finite,with the corresponding central charge *** using the quasi-local charge and introducing a plausible cut-off,we find that the higher order terms of the asymptotic Killing vectors,which could not be determined through the effective action approach,contribute to the central charge as *** also show that the boundary conditions suggested by Guica et al.[***.D 80 (2009)124008] lead to a divergent first-order boundary effective action.

关键词： asymptotic boundary charge

Two-weight Norm Inequalities for Local Fractional Integrals on Gaussian Measure Spaces

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Acta Mathematica Sinica,English Series 2022年第7期38卷 1203-1228页

作者： bo ning DI Qian Jun HE Dun Yan YAN School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049P.R.China School of Applied Science Beijing Information Science and Technology UniversityBeijing 100192P.R.China

In this paper,the authors establish the two-weight boundedness of the local fractional maximal operators and local fractional integrals on Gaussian measure spaces associated with the local *** precisely,the authors first obtain the two-weight weak-type estimate for the locala fractional maximal operators of orderαfrom L^(p)(v)to L^(q,∞)(u)with 1≤p≤qa A_(p,q,a)^(b') ,and then obtain the two-weight weak-type estimate for the local fractional *** addition,the authors obtain the two-weight strong-type boundedness of the local fractional maximal operators under a condition of(u,v)∈M_(p,q,a)^(6a+9√da^2) and the two-weight strong-type boundedness of the local fractional *** estimates are established by the radialization method and dyadic approach.

关键词： Local fractional integral local fractional maximal operator two-weight inequality Gaussian measure space

Broadcast encryption schemes based on RSA

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The Journal of China Universities of Posts and Telecommunications 2009年第1期16卷 69-75页

作者： MU ning-bo HU Yu-pu OU Hai-wen The Ministry of Education Key Laboratory of Computer Networks and Information Security Xidian University Xi'an 710071 China Key Laboratory of Information Security and Secrecy Beijing Institute of Electronic Science and Technology Beijing 100070 China

Three broadcast schemes for small receiver set using the property of RSA modulus are presented. They can solve the problem of data redundancy when the size of receiver set is small. In the proposed schemes, the center uses one key to encrypt the message and can revoke authorization conveniently. Every authorized user only needs to store one decryption key of a constant size. Among these three schemes, the first one has indistinguishability against adaptive chosen ciphertext attack （IND-CCA2） secure, and any collusion of authorized users cannot produce a new decryption key but the sizes of encryption modulus and ciphertext are linear in the number of receivers. In the second scheme, the size of ciphertext is half of the first one and any two authorized users can produce a new decryption key, but the center can identify them using the traitor tracing algorithm. The third one is the most efficient but the center cannot identify the traitors exactly.

关键词： broadcast encryption traitor tracing authorization revocation RSA

Preparation of W-TiC alloys from core-shell structure powders synthesized by an improved wet chemical method

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Rare Metals 2023年第4期42卷 1378-1386页

作者： Shao-Ting Lang Qing-Zhi Yan ning-bo Sun Xiao-Xin Zhang Institute of Nuclear Materials University of Science and Technology BeijingBeijing100083China

In order to improve the homogeneous distribution of the TiC particles and facilitate the TiC particles to distribute in the tungsten grain interiors,two kinds of TiCdoped tungsten precursors with a core-shell structure were prepared by an improved wet chemical method at different reaction temperature ***,fine platelike precursor(200-400 nm)and flower-like precursor(approximately 1.25μm)are *** reduction and sintering,the microstructures of the samples were characterized by scanning electron microscopy and transmission electron *** the sample sintered from the platelike precursor,TiC particles with sizes in the range of40-300 nm and an average size of approximately 80 nm were uniformly distributed in the tungsten matrix with a high share in the grain ***,in the sample sintered from the flower-like precursor,the TiC particles with sizes in the range of 50-700 nm are significantly aggregated and non-uniformly distributed in the tungsten *** a result,the sample sintered from the plate-like precursor achieves higher mechanical properties and a much narrower range of bending strength values than that sintered from the flower-like *** average bending strength of the sample sintered from the plate-like precursor is 655 MPa,which is higher than that of the sample sintered from the flower-like precursor(524 MPa).Different reaction mechanisms and dispersing stabilities of the TiC particles at different temperature conditions should be accounted for the differences between the two samples.

关键词： Wet chemical method W-TiC alloy Core-shell structures Spark plasma sintering Microstructure characterization

Aφ6-m Tunnel boring Machine Steel Arch Splicing Manipulator

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Chinese Journal of Mechanical Engineering 2022年第2期35卷 121-134页

作者： Yuanfu He Yimin Xia Zhen Xu Jie Yao bo ning Xuemeng Xiao College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha 410083China China Railway Construction Heavy Industry Co.Ltd. Changsha 410100China China Railway Siyuan Survey and Design Group Co.Ltd. Wuhan 430063China National-Local Joint Engineering Research Center of Underwater Tunnelling Technology Wuhan 430063China

Robotic splicing of steel arches is a challenging task that is necessary to realize the grasping and docking of steel arches in a limited *** arches often have a mass of more than 200 kg and length of more than 4 *** to the large volume and mass of steel arches and the high requirements for accurately positioning the splicing,it is difficult for a general manipulator to meet the stiffness *** enhance the structural stiffness of the steel arch splicing manipulator,a single-degree-of-freedom(DOF)closed-loop mechanism was added to the grasping structure of the *** on the basic principle of structural synthesis,a solution model of the single-DOF closed-loop mechanism was developed,and alternative kinematic pairs of the mechanism with different input constraints and output requirements were *** on this model,a design method for a single-DOF closed-loop grasping mechanism and a posture adjustment mechanism for a steel arch was *** with the same dimensional subspace equivalence principle of the graphical-type synthesis method,12 types of steel arch splicing manipulator were *** analyzing the motion/force transmission and structural complexity of the steel arch splicing manipulators,the best scheme was selected.A prototype of the steel arch splicing manipulator was *** software was used to obtain clearly the output trajectory of the end of the *** relative spatial positions of the upper and lower jaws under different working stages were analyzed,demonstrating that the manipulator satisfied the grasping *** a steel arch splicing experiment,the grasping effect,docking accuracy,and splicing efficiency of the manipulator met the design *** steel arch splicing manipulator can replace the manual completion of the steel arch splicing operation,significantly improving the operation efficiency.

关键词： Steel arch splicing manipulator Single-DOF closed-loop mechanism Screw theory Graphical-type synthesis method Mechanism design

Effect of annealing treatment on microstructure and mechanical properties of Al/Ni multilayer composites during accumulative roll bonding (ARB) process

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Journal of Iron and Steel Research International 2020年第1期27卷 96-104页

作者： Hui-wen Zhu Bao-yi Yu Hao Zhang bo-ning Yu Shu-ning Lv Li Zheng Run-xia Li School of Material Science and Engineering Shenyang University of TechnologyShenyang 110870LiaoningChina School of Mechanical Engineering Dongguan University of TechnologyDongguan 523808GuangdongChina

Al/Ni multilayer composites are produced by accumulative roll bonding process and then annealed with different temperatures and *** images,microstructure and mechanical properties of Al/Ni multilayer composites are *** for the macroscopic images,although there was an edge crack along the rolling direction at the third pass,the defect of composites was not serious and the forming quality of composites was relatively *** yield strength and elongation of Al/Ni multilayer composites are improved after the annealing treatment;however,with the increase in annealing temperature and time,the yield strength and ciongation of Al/Ni multilayer composites are *** the process of annealing treatment,aluminum atoms diffuse in the way of vacancy diffusion,which results in the formation of Al3Ni intermetallic phase at Al/Ni interface and Kirkendall void in the aluminum *** content of Al3Ni intermetallic phase and Kirkenckill void would increase with the increase in annealing temperature and time.

关键词： Al/Ni multilayer composite Accumulative roll bonding process Annealing treatment Interrnetallic phase

Induced Subgraphs with Large Degrees at End-vertices for Hamiltonicity of Claw-free Graphs

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Acta Mathematica Sinica,English Series 2016年第7期32卷 845-855页

作者： Roman CADA Bin Long LI bo ning Sheng Gui ZHANG Department of Mathematics University of West Bohemia Centre of Excellence ITI - Institute for Theoretical Computer Science Charles University European Centre of Excellence NTIS - New Technologies for the Information Society P.O. Box 314 306 14 Pilsen Czech Republic Department of Applied Mathematics Northwestern Polytechnical University Xi'an 710072 P. R. China Center for Applied Mathematics Tianjin University Tianjin 300072 P. R. China

A graph is called claw-free if it contains no induced subgrapn lsomorpmc to K1,3. Matthews and Sumner proved that a 2-connected claw-free graph G is Hamiltonian if every vertex of it has degree at least （[V（G）I - 2）/3. At the workshop CSzC （Novy Smokovec, 1993）, Broersma conjectured the degree condition of this result can be restricted only to end-vertices of induced copies of N （the graph obtained from a triangle by adding three disjoint pendant edges）. Fujisawa and Yamashita showed that the degree condition of Matthews and Sumner can be restricted only to end-vertices of induced copies of Z1 （the graph obtained from a triangle by adding one pendant edge）. Our main result in this paper is a characterization of all graphs H such that a 2-connected claw-free graph G is Hamiltonian if eachend-vertex of every induced copy of H in G has degree at least IV（G）I/3 ＋ 1. This gives an affirmative solution of the conjecture of Broersma up to an additive ***-vertex of every induced copy of H in G has degree at least IV（G）I/3 ＋ 1. This gives an affirmative solution of the conjecture of Broersma up to an additive constant.

关键词： Induced subgraph large degree end-vertex claw-free graph Hamiltonian graph