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Effect of Solution Treatment on the Microstructure and Mechanical Properties of Sand-Cast Mg–9Gd–4Y–0.5Zr Alloy

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Acta Metallurgica Sinica(English Letters) 2018年第2期31卷 189-198页

作者： Jing-Li Li Na zhang xiao-Xuan Wang Di Wu Rong-Shi Chen The Group of Magnesium Alloys and Their Applications Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Materials Science and Engineering University of Science and Technology of China Hefei 230026 China AVIC Shenyang Liming Aero--Engine Group Corporation Shenyang 110043 China

Sand-cast Mg–9Gd–4Y–0.5 Zr（wt%） alloy was solution-treated at 500–565 ℃ in the time range of 0.5–30 h in air or vacuum to investigate its microstructure evolution and mechanical properties. The results showed that solution treatment temperature had a significant influence on the dissolving rate of eutectic phase and grain growth. Taken both of them into consideration, 510–520 ℃ was considered to be the optimum solution treatment temperature range for this *** should be noted that the trace（0.4–0.9 vol%） and insoluble cuboid-shaped phase precipitated during solution treatment was identified to be YH2, of which the hydrogen was thought to come from both the melting and solution heating *** addition, the 3D morphology and dissolving process of Mg24（Gd,Y）5 eutectic phases in the as-cast alloy were also discussed via in-situ observation under X-ray tomography.

关键词： Mg-Gd-Y-Zr alloy Solution treatment Microstructure Rare-earth hydride

Transmit scheme to improve coverage in simulcast system based on wideband channel measurement in indoor at 6 GHz

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The Journal of China Universities of Posts and Telecommunications 2013年第2期20卷 48-53,72页

作者： XIN Liang zhang Jian-hua GAO Jun-jun LI xiao-fan Chipset R&D-Systems Engineering-Systems Design VIATelecom Wireless Technology Innovation Institute Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts and Telecommunications State Ratio-monitoring-center Testing Center

Array gain would be well exploited to improve power coverage if some powerful multipath components from different radio links can coherently combine at the receiver （Rx）. Thus, in this paper, an algorithm is proposed for transmission in simulcast system, where partial channel state information （CSI） is needed. Based on measured multipath channel, performance of the proposed algorithm is evaluated. According to simulation results, the proposed algorithm outperforms the direction summation （DS） scheme and multipath antenna diversity （MAD） algorithm, with 2～4 dB advantage over the latters. Especially in line of sight （LOS） scenario, the advantage is more obvious. Besides, the proposed algorithm brings more gain with increasing number of transmit antennas without additional power. Finally, robustness of the proposed algorithm is examined with imperfect CSI.

关键词： channel measurement delay difference phase rotation coverage robustness

Ground State Properties of Superheavy Nuclei in Macroscopic-Microscopic Model

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Communications in Theoretical Physics 2008年第9期50卷 707-714页

作者： ZHI Qi-Jun REN Zhong-Zhou zhang xiao-Ping ZHENG Qiang School of Science Guizhou Normal University Guiyang 550001 China Department of Physics Nanjing University Nanjing 210008 China Center of Theoretical Nuclear Physics National Laboratory of Heavy-Ion Accelerator Lanzhou 730000 China Joint Center for Particle Nuclear Physics and Cosmology Nanjing University Nanjing 210008 China

The ground state properties of superheavy nuclei are systematically calculated by the macroscopic-microscopic (MM) model with the Nilsson *** calculations well produced the ground state binding energies,α-decay energies,and half lives of superheavy *** calculated results are systematically compared with availableexperimental *** calculated results are also compared with theoretical results from other MM models and fromrelativistic mean-field *** calculations and comparisons show that the MM model is reliable in superheavy regionand that the MM model results are not very sensitive to the choice of microscopic single-particle potential.

关键词： macroscopic-microscopic model.superheavy nuclei binding energy half life

Feasibility of aluminum recovery and MgAl_2O_4 spinel synthesis from secondary aluminum dross

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International Journal of Minerals,Metallurgy and Materials 2019年第3期26卷 309-318页

作者： Yong zhang Zhao-hui Guo Zi-yu Han Xi-yuan xiao Chi Peng School of Metallurgy and Environment Central South University

The feasibility of aluminum recovery from secondary aluminum dross by extraction with NaOH solution and the subsequent synthesis of MgAl_2O_4 spinel by sintering the extracted slag were studied. The extraction percentage of soluble aluminum from the dross reached 80% at a temperature of 353 K, liquid-to-solid ratio of 12 mL·g^(-1), stirring speed of 300 r·min^(-1), and an extraction time of 15 min; the hydrolysis percentage of AlN reached 40% with an extraction time of 30 min. The activation energies of the soluble aluminum and AlN extracted from the dross were 7.15 and 8.98 kJ·mol^(-1), respectively, indicating that their kinetics were controlled by outer diffusion without a product layer. The extracted slag was sintered in the temperature range 1373–1773 K; MgAl_2O_4 spinel with a compressive strength as high as 69.4 MPa was produced in the sample sintered at 1673 K for 3 h. This value exceeds the threshold(40 MPa) prescribed by the National Standard for the Magnesia and Magnesia-alumina Refractory Bricks of China(GB/T 2275-2007). These results establish the effectiveness of aluminum recovery from secondary aluminum dross and subsequent MgAl_2O_4 spinel synthesis.

关键词： secondary aluminum dross reuse extraction sintering magnesium aluminate spinel

Two-dimensional Sn2Ta2O7 nanosheets as efficient visible lightdriven photocatalysts for hydrogen evolution

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Rare Metals 2019年第5期38卷 397-403页

作者： xiao-Shuai Wang Chao Zhou Run Shi Qin-Qin Liu Tie-Rui zhang School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Two-dimensional Sn2Ta2O7 nanosheets with a thickness of^10 nm were successfully prepared through a novel tantalic acid-based solid-state reaction method at reduced *** as-obtained samples were characterized by powder X-ray diffraction(XRD),ultraviolet–visible(UV–Vis)diffuse reflectance spectra,scanning electron microscopy(SEM),transmission electron microscopy(TEM)and Brunauer–Emmett–Teller(BET)*** photocatalytic performance of Sn2 Ta2 O7 nanosheets was evaluated by photocatalytic water splitting for hydrogen evolution under visible light irradiation(k C 400 nm).The Sn2Ta2O7 nanosheets with a large surface area of 25.9 m^2·g^-1 showed higher H2 production activity,which was about 4.4 times higher than that of bulk Sn2 Ta2O7 in lactic acid aqueous solutions using Pt as a *** improved photocatalytic performance mainly benefited from the nanosheet structure,which provided abundant surface active sites and facilitated the photogenerated charge carrier separation *** workmay open up new opportunity to develop novel nanostructured tantalum-based semiconductors with improved catalytic performance for solar energy conversion.

关键词： Sn2Ta2O7 Nanosheets Visible light Photocatalysis Hydrogen evolution

Non-synchronous bulk photovoltaic effect in two-dimensional interlayer-sliding ferroelectrics

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npj Computational Materials 2022年第1期8卷 1328-1335页

作者： Rui-Chun xiao Yang Gao Hua Jiang Wei Gan Changjin zhang Hui Li Institute of Physical Science and Information Technology and Information Materials and Intelligent Sensing Laboratory of Anhui Province Anhui UniversityHefei230601China Department of Physics University of Science and Technology of ChinaHefei230026China School of Physical Science and Technology Soochow UniversitySuzhou215006China High Magnetic Field Laboratory Chinese Academy of SciencesHefei230031China

Spontaneous polarization and bulk photovoltaic effect(BPVE)are two concomitant physical properties in ferroelectric *** flipping of ferroelectric order usually accompanies the switching of BPVE in all directions because both of them are reversed under the inversion *** this study,we report the non-synchronous BPVE in two-dimensional(2D)interlayer-sliding ferroelectric materials featuring unswitchable in-plane BPVE(light-induced photocurrent in the xy plane)and switchable out-of-plane BPVE(light-induced polarization along the z-direction).Symmetry analysis within the abstract bilayer crystal model and first-principles calculations validate these BPVE *** is because the positive and negative ferroelectric states caused by interlayer sliding are related by mirror symmetry which cannot flip all the BPVE tensor *** finding extends the understanding of the relationship between ferroelectricity and *** one hand,the switchable out-of-plane BPVE can be used to design switchable photoelectric *** the other hand,the in-plane BPVE is robust against the ferroelectric flipping,and the unswitchable character is beneficial to construct larger-scale photoelectric devices.

关键词： polarization ferroelectric interlayer

EXISTENCE RESULTS FOR SINGULAR FRACTIONAL p-KIRCHHOFF PROBLEMS

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Acta Mathematica Scientia 2022年第3期42卷 1209-1224页

作者： Mingqi xiang Vicent iu D.RADULESCU Binlin zhang College of Science Civil Aviation University of ChinaTianjin 300300China Faculty of Applied Mathematics AGH University of Science and Technologyal.Mickiewicza 3030-059 Krak´owPoland Department of Mathematics University of CraiovaStreet A.I.Cuza No.13200585 CraiovaRomania Institute of Mathematics Physics and MechanicsJadranska 191000 LjubljanaSlovenia College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590China

This paper is concerned with the existence and multiplicity of solutions for singular Kirchhoff-type problems involving the fractional p-Laplacian *** precisely,we study the following nonlocal problem:{M (∫∫_(R2N)|x|^(α1p)|y|^(α2p)|u(x) − u(y)|^(p)/|x − y|^(N+ps) dxdy)L_(p)^(s)u = |x| ^(β)f(u) in Ω,u = 0 in R^(N) \ Ω,where L_(p)^(s) is the generalized fractional p-Laplacian operator,N≥1,s∈(0,1),α_(1),α_(2),β∈R,Ω■R^(N) is a bounded domain with Lipschitz boundary,and M:R0^(+)→R0^(+),f:Ω→R are continuous ***,we introduce a variational framework for the above ***,the existence of least energy solutions is obtained by using variational methods,provided that the nonlinear term f has(θ_(p-1))-sublinear growth at ***,the existence of infinitely many solutions is obtained by using Krasnoselskii’s genus ***,we obtain the existence and multiplicity of solutions if f has(θ_(p-1))-superlinear growth at *** main features of our paper are that the Kirchhoff function may vanish at zero and the nonlinearity may be singular.

关键词： Fractional Kirchhoff equation singular problems variational and topological methods

Role of Ferrel cell in daily variability of Northern Hemisphere Annular Mode

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Chinese Science Bulletin 2014年第27期59卷 3457-3464页

作者： xiao-Feng Li Jianping Li xiangdong zhang Cheng Sun State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences International Arctic Research Center University of Alaska Fairbanks Fairbanks Alaska 99775 USA

The Northern Hemisphere Annular Mode(NAM) represents the zonally symmetric planetary-scale atmospheric mass fluctuations between middle and high latitudes, whose variations have shown a large impact on other components of the climate system. Previous studies have indicated that the NAM is correlated with the Ferrel cell in their monthly or longer timescale ***, there have been few studies investigating their connections at daily timescale, though daily variability of NAM has been suggested to be an important component and has significant implication for weather forecast. The results from this study demonstrate that variability of the Ferrel cell leads that of the NAM by about 1–2 days. This statistically identified temporal phase difference between NAM and Ferrel cell variability can be elucidated by meridional mass redistribution. Intensified(weakened)Ferrel cell causes anomalously smaller(larger) poleward mass transport from the middle to the high latitudes,resulting in an increase(a decrease) in mass in the middle latitudes and a decrease(an increase) in the high *** a consequence, anomalously higher(lower) poleward pressure gradient forms and the NAM subsequently shifts to a positive(negative) phase at a time lag of 1–2 days. The findings here would augment the existing knowledge for better understanding the connection between the Ferrel Cell and the NAM, and may provide skillful information for improving NAM as well as daily scale weather prediction.

关键词：环流变化北半球异性日变环状高纬度地区大气质量时间尺度

New insights into the significance of the BCR repertoire in B-1 cell development and function

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Cellular & Molecular Immunology 2019年第9期16卷 772-773页

作者： xiaohui Wang Cong Ye xiang Lin Kongyang Ma Fan xiao Lingli Dong Liwei Lu Department of Pathology and Shenzhen Institute of Research and Innovation The University of Hong KongHong KongChina Department of Rheumatology and Immunology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubeiChina

As an important player of innate immunity,B-1 cells have been characterized by natural antibody production and rapid immune *** on their expression or lack of CD5,B-1 cells are further separated into B-1a and B-1b subsets.1 Although extensive studies have demonstrated a pivotal role of conventional B cells in adaptive immunity,there is increasing evidence indicating the close associations of B-1a cells with self-reactivity,autoimmunity,infection,and even leukemia.2–4 Here,we describe recent advances that lead to a clearer understanding of B-1 cell development with a focus on new insights into the significance of the B-cell receptor(BCR)repertoire in B-1a cell biology and discuss the potential strategies for specific targeting of B-1a cells under pathological settings.

关键词： immunity insight function