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Effects of in-situZrB_2 nanoparticles and scandium on microstructure and mechanical property of 7N01 aluminum alloy

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Journal of Rare Earths 2024年第3期42卷 612-620,I0007页

作者： Xizhou Kai Yuhui Wang Ruikun Chen Yanjie Peng Anjun Shi Ran Tao Xiangfeng Liang Guirong Li Gang Chen xiaojing xu Yutao Zhao School of Material Science and Engineering Jiangsu UniversityZhenjiang212013China Institute for Advanced Manufacturing and Modern Equipment Technology Jiangsu UniversityZhenjiang212013China

In this study, the in-situ synthesized ZrB_(2) nanoparticles and rare earth Sc were introduced to enhance the strength and ductility of 7N01 aluminum alloy, via the generation of high-melting and uniform nanodispersoids. The microstructure and mechanical property evolution of the prepared composites and the interaction between ZrB_(2) and Sc were studied in detail. The microstructure investigation shows that the introduction of rare earth scandium(Sc) can promote the distribution of ZrB_(2) nanoparticles, by improving their wettability to the Al melt. Meanwhile, the addition of rare earth Sc also modifies the coarse Al Zn Mg Mn Fe precipitated phases, refines the matrix grains and generates high-melting Al_3(Sc,Zr)/Al_3Sc nanodispersoids. Tensile tests of the composites show that with the combinatorial introduction of ZrB_(2) and Sc, the strength and ductility of the composites are improved simultaneously compared with the corresponding 7N01 alloy, ZrB_(2) /7N01 composite and Sc/7N01 alloy. And the optimum contents of ZrB_(2) and Sc are 3 wt% and 0.2 wt% in this study. The yield strength, ultimate strength and elongation of(3 wt% ZrB_(2) +0.2 wt% Sc)/7N01 composite are 477 MPa, 506 MPa and 9.8%, increased about 18.1%, 12.2%and 38% compared to 7N01 alloy. Furthermore, the cooperation strengthening mechanisms of ZrB_(2) and Sc are also discussed.

关键词： 7N01 aluminum alloy In-situ ZrB_(2)nanoparticles Rare earth Sc Microstructure Mechanical property Mechanism

Effect of Heat Treatment on Microstructure and Mechanical Properties of Multiscale SiC_p Hybrid Reinforced 6061 Aluminum Matrix Composites

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 174-181页

作者：吴健铭许晓静 ZHANG xu LUO Yuntian LI Shuaidi HUANG Lin Institute for Advanced Manufacturing and Modern Equipment Technology Jiangsu UniversityZhenjiang 212013China

The performance of solid solution aging treatment on aluminum matrix composites prepared by powder metallurgy and reinforced with 6061 aluminum alloy powder as matrix;meanwhile, nano silicon carbide particles(nm Si Cp), submicron silicon carbide particles(1 μm Si Cp) and Ti particles were studied. The Al/Si Cp composite powder was prepared by high-energy ball milling, and then cold-pressed, sintered, hotextruded, and then heat-treated with different solution temperatures and aging times for the extruded composites. Optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy(EDS), X-ray diffractometer(XRD) and extrusion testing were used to analyze and test the microstructure and mechanical properties of aluminum matrix composites. The results show that after the multi-stage solid solution at 530 ℃×2 h+535 ℃×2 h+540 ℃×2 h, the particles are mainly equiaxed grains and uniformly distributed. There is no reinforcement agglomeration, and the surface is dense and the insoluble phase is basically dissolved. In the matrix, the strengthening effect is good, and the hardness and compressive strength are 179.43 HV and 680.42 MPa, respectively. Under this solution process, when the aluminum matrix composites are aged at 170 ℃ for 10 h, the hardness and compressive strength can reach their peaks and increase to 195.82 HV and 721.48 MPa, respectively.

关键词： aluminum matrix composites Si C particles multiscale hybrid enhancement heat treatment mechanical properties

Microstructure and Mechanical Properties of Al-11.3Zn-3.2Mg-1.3Cu-0.2Zr-0.1Sr-x Ti Extruded Aluminum Alloy with Different Aging Process

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Journal of Wuhan University of Technology(Materials Science) 2023年第5期38卷 1161-1168页

作者： BAO Guoning xu xiaojing HUA Yinqun ZHANG Bin WEI Tao HONG Zhiheng LIU Lele HAN Mengnan SHA Shaohui Institute for Advanced Manufacturing and Modern Equipment Technology Jiangsu UniversityZhenjiang 212013China

The influences of adding different amount of Ti(0%,0.39%,0.87%)and three kinds of difierent aging processes(T6,T6I6,RRA)on the microstructure and properties of Al-11.3Zn-3.2Mg-1.3Cu-0.2Zr-0.1Sr were investigated.Results show that an appropriate amount of Ti can effectively inhibit grain growth and thus achieve the efiect of grain refinement.The contribution of dislocation density and dislocation strengthening become the biggest when Ti content is 0.39%.At the same time,the intergranular corrosion depth is the lowest when Ti content is 0.39%.Among the three aging processes,the alloys reach the greatest hardness and tensile strength in T6I6.The biggest tensile strength reaches 716.77 MPa.However,when aging at RRA,the alloys obtain the greatest elongation,reaching 7.2%,as well as the good corrosion resistance.

关键词： Al-Zn-Mg-Cu Ti content aging process microstructure properties

F-Law collision and system state recognition

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Journal of Systems Engineering and Electronics 2007年第2期18卷 259-264页

作者： Shi Kaiquan xu xiaojing School of Mathematics and System Sciences Shandong Univ. Jinan 250100 P.R. China School of Mathematics Sciences Liaocheng Univ. Liaocheng 252059 P.R. China

Using function one direction S-rough sets （function one direction singular rough sets）, f-law and F- law and the concept of law distance and the concept of system law collided by F-law are given. Using these concepts, state characteristic presented by system law collided by F-law and recognition of these states characteristic and recognition criterion and applications are given. Function one direction S-rough sets is one of basic forms of function S-rough sets （function singular rough sets）. Function one direction S-rough sets is importance theory and is a method in studying system law collision.

关键词： Function one direction S-rough sets F -law Collision Characteristic recognition Recognition criterion Applications.

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Journal of Systems Engineering and Electronics 2008年第5期19卷 945-951页

作者： Li Jian xu xiaojing Shi Kaiquan School of Mathematics and System Science Shandong Univ. Jinan 250100 P. R. China School of Computer Science & Technology Shandong Jianzhu Univ. Jinan 250101 P. R. China

Based on rough similarity degree of rough sets and close degree of fuzzy sets, the definitions of rough similarity degree and rough close degree of rough fuzzy sets are given, which can be used to measure the similar degree between two rough fuzzy sets. The properties and theorems are listed. Using the two new measures, the method of clustering in the rough fuzzy system can be obtained. After clustering, the new fuzzy sample can be recognized by the principle of maximal similarity degree.

关键词： rough fuzzy set rough similarity degree rough close degree clustering recognition of rough pattern,maximal similarity degree principle.

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Journal of Systems Engineering and Electronics 2008年第2期19卷 311-315页

作者： xu xiaojing Li Jian Shi Kaiquan School of Computer Science & Technology Shandong Jianzhu Univ. Jinan 250101 P. R. China School of Mathematics and System Science Shandong Univ. Jinan 250100 P. R. China

The definition of rough similarity degree is given based on the axiomatic similarity degree, and the properties of rough similarity degree are listed. Using the properties of rough similarity degree, the method of clustering in rough systems can be obtained. After clustering, a new sample can be recognized by the principle of maximal rough similarity degree.

关键词： rough similarity degree clustering recognition of rough pattern maximal similarity degree principle.

Spectrum Sensing for OFDMA Using Multicarrier Covariance Matrix Aware CNN

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ZTE Communications 2022年第3期20卷 61-69页

作者： ZHANG Jintao HE Zhenqing RUI Hua xu xiaojing National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengdu 611731China ZTE Corporation Shenzhen 518057China State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen 518055China

We consider spectrum sensing problems in the orthogonal frequency division multiplexing access(OFDMA)cognitive radio scenario,where a secondary user with multiple antennas detects several consecutive subcarriers of an entire OFDM symbol occupied by multiple primary users.Specifically,an OFDM multicarrier covariance matrix convolutional neural network(CNN)-based approach is proposed for simultaneously detecting the occupancy of all OFDM subcarriers,where the multicarrier sample covariance matrix array is specially set as the input of the CNN.The proposed approach can efficiently learn the energy information and correlation information between antennas and between subcarriers to significantly improve the spectrum sensing performance.Numerical results demonstrate that the proposed method has a substantial performance advantage over the state-of-the-art spectrum sensing methods in an OFDM A scenario under the 5 G new radio network.

关键词： cognitive radio spectrum sensing OFDMA deep learning 5G new radio

中国职业教育高质量发展水平测度、区域差异及空间效应

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职业技术教育 2024年第15期45卷 8-17页

作者：蔡文伯徐晓晶石河子大学师范学院石河子832003

我国已建立全球最大规模的职业教育体系,高质量发展是职业教育改革的关键议题。基于新发展理念,构建职业教育高质量发展评价指标体系,利用熵权法、Dagum基尼系数以及空间自相关分析测算2014-2022年中国职业教育高质量发展水平,并对全国... 详细信息

我国已建立全球最大规模的职业教育体系,高质量发展是职业教育改革的关键议题。基于新发展理念,构建职业教育高质量发展评价指标体系,利用熵权法、Dagum基尼系数以及空间自相关分析测算2014-2022年中国职业教育高质量发展水平,并对全国各区域各省份职业教育高质量发展的区域差异、空间效应进行分析。研究发现:中国职业教育高质量发展水平较低,总体发展水平呈波动上升趋势;区域间与区域内职业教育高质量发展水平均存在明显差异;空间上职业教育高质量发展水平呈现“高—高”集聚与“低—低”集聚特征。基于此,中国职业教育高质量发展的方向是:扬长补短,以新发展理念为指导,全面提高职业教育高质量发展水平;优化布局,以资源投入为牵引,缩小区域间职业教育高质量发展水平差距;因地制宜,以实际情况为基础,制定差异化职业教育高质量发展策略。

关键词：职业教育高质量发展测度体系区域差异空间效应

SOME ENTROPY INEQUALITIES FOR A QUASILINEAR DEGENERATE HYPERBOLIC EQUATION

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Journal of Partial Differential Equations 2005年第4期18卷 289-303页

作者： Yuan Hongjun xu xiaojing Institute of Mathematics Jilin University Changchun 130012 China Institute of Mathematics Jilin University Changchun 130012 Institute of Applied Physics and Computational Mathematics Beijing 100088 China

The aim of this paper is to discuss some degenerate hyperbolic equation u(t) + phi(u)(x) = 0, where phi is an element of C-1(R {0}) boolean AND C-2(R {0}) is a nondecreasing function in R where (-infinity, +infinity). Some entropy inequalities are obtained and can be applied to study the existence of local BV solutions of the above equation with local finite measures as initial conditions.

关键词：熵不等式准线性双曲线方程退化方程 BV解