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Optimisation of alloy composition for highly-formable magnesium sheet

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International Journal of Minerals,Metallurgy and Materials 2022年第7期29卷 1388-1395页

作者： Zhuoran Zeng Mingzhe Bian Shiwei Xu Weineng Tang Chris Davies Nick Birbilis Jianfeng Nie College of Engineering and Computer Science Australian National UniversityACT.2601Australia Department of Materials Science and Engineering Monash UniversityVIC 3800Australia State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China Research Institute(R&D Center) Baosteel Group CorporationShanghai 201999China Department of Mechanical and Aerospace Engineering Monash UniversityVIC 3800Australia

The effectiveness of Ca or Gd addition on ductility and formability of Mg-Zn-Zr based dilute alloys in deep drawing has not been systematically compared previously.In this study,formable Mg-Zn-Gd-Zr and Mg-Zn-Ca-Zr sheet alloys are produced by hot rolling.These sheets have similarly weakened basal texture,but the sheet of the Mg-Zn-Gd-Zr alloys has higher ductility and formability than that of Mg-Zn-Ca-Zr alloys.The combined addition of 0.2wt%Ca and 0.4wt%Gd to the Mg-1Zn-0.5Zr(wt%)alloy leads to a Mg-1Zn-0.4Gd-0.2Ca-0.5Zr alloy that has even better ductility,and its formability during deep drawing is comparable to the benchmark Al6016 sheet.An increase in Ca content from 0.2wt%to 0.5wt%leads to decreased sheet ductility and formability,predominantly due to grain boundary embrittlement.

关键词： magnesium sheet alloy texture microstructure formability solute segregation

Lithium mapping in a Mg-9Li-4Al-1Zn alloy using electron energy-loss spectroscopy

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Journal of Magnesium and Alloys 2023年第4期11卷 1170-1179页

作者： Yu Zhang Laure Bourgeois Yu Chen Zhuoran Zeng Nick Birbilis Philip N.H.Nakashima Department of Materials Science and Engineering Monash UniversityVIC 3800Australia Monash Centre for Electron Microscopy Monash UniversityVIC 3800Australia College of Engineering and Computer Science Australian National UniversityACT 2601Australia Faculty of Science Engineering and Built EnvironmentDeakin UniversityVIC 3125Australia

Magnesium-lithium alloys with high lithium content have been attracting significant attention because of their low density,high formability and corrosion resistance.These properties are dependent on the distribution of lithium,which is difficult to map in the presence of magnesium.In this work,a ratio spectrum-imaging method with electron energy-loss spectroscopy(EELS)is demonstrated,which enables the mapping of lithium.In application to LAZ941(Mg-9Li-4Al-1Zn in wt.%),this technique revealed that a key precipitate in the microstructure,previously thought by some to be Mg_(17)Al_(12),is in fact rich in lithium.This result was corroborated with a structural investigation by high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),showing this phase to be Al_(1-x)Zn_(x)Li,with x<<1.This work indicates the potential offered by this technique for mapping lithium in materials.

关键词： Lithium mapping Magnesium alloys Electron energy-loss spectroscopy(EELS) High-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)

Effect of the processing route on the microstructure and mechanical behavior of superlight Mg-9Li-1Zn alloy via friction stir processing

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Journal of Magnesium and Alloys 2022年第11期10卷 3064-3081页

作者： Mengran Zhou Zhuoran Zeng Chun Cheng Yoshiaki Morisada Qingyu Shi Jian-Yih Wang Hidetoshi Fujii Joining and Welding Research Institute(JWRI) Osaka UniversityOsakaJapan Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Tribology Tsinghua UniversityBeijingChina Key Laboratory for Advanced Materials Processing Technology Ministry of Education of China Tsinghua UniversityBeijing 100084China College of Engineering and Computer Science Australian National UniversityACT 2601Australia Department of Materials Science and Engineering National Dong-Hwa UniversityHwa-LianTaiwanChina

In this study, the effect of the processing route using a friction stir processing(FSP) method on the microstructure and mechanical behavior of a Mg-9Li-1Zn alloy was systematically investigated. In the FSP method, the odd-numbered(1st and 3rd) process directions and even-numbered(2nd and 4th) passes were alternated to distribute the strain throughout the whole processed zone uniformly. Consequently, the processed zone had a much more uniform microstructure and hardness distribution than the processed zone obtained using the conventional FSP method. Using this method, the grain size of a Mg-9Li-1Zn sheet alloy was refined from ~31 μm to ~0.21 μm with uniformly distributedα and β phases. The processed alloy exhibited a high strength-ductility synergy with an ultimate tensile strength(UTS) of 220.1 MPa and total elongation of 70.0% at a strain rate of 10^(-3)s^(-1), overwhelmingly higher than those of the base metal, 155.6 MPa in UTS and 36.0%in elongation. The in-situ SEM-DIC analysis and TEM observation demonstrated that such an outstanding ductility with moderate strength is caused by grain boundary sliding, the dominant deformation mechanism of the ultra-fine-grained sample after FSP. The processing route with reverse processing direction was proven to be efficient in producing the ultrafine grain size microstructure and improving the mechanical properties of superlight Mg-9Li-1Zn alloy.

关键词： Mg-Li-Zn alloy Friction stir processing Microstructure In-situ SEM-DIC Mechanical properties

Effect of extrusion speed on microstructure and mechanical properties of the Mg-Ca binary alloy

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Journal of Magnesium and Alloys 2021年第4期9卷 1304-1310页

作者： Jingren Li Aiyue Zhang Hucheng Pan Yuping Ren Zhuoran Zeng Qiuyan Huang Changlin Yang Lifeng Ma Gaowu Qin Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819China Department of Materials Science and Engineering Monash UniversityVic.3800Australia Institute of Metal Research Chinese Academy of SciencesShenyang 110016China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’anShaanxi 710072China Shanxi Provincial Key Laboratory of Metallurgical Equipment Design and Technology Taiyuan University of Science and TechnologyTaiyuan 030024China

This work reported the effect of extrusion speeds on the microstructures and mechanical properties of Mg-Ca binary alloy.The results showed that yield strength of the as-extruded Mg-1.2wt.%Ca alloys decrease from∼360MPa to∼258MPa as the ram speed increases from 0.4mm/s to 2.4 mm/s,and the elongation increases from∼3.9%to∼12.2%.The microstructure changes from bimodal grain feature to the complete dynamical recrystallization(DRX)with increase of the extrusion speed.The ultrafine DRXed grains in size of∼0.85μm,the numerous nano-Mg_(2)Ca particles dispersing along the grain boundaries and interiors,as well as the high density of residual dislocations,should account for the high strength.It is believed that the high degree of dynamic recrystallization and the resulting texture randomization play the critical roles in the ductility enhancement of the high-speed extruded Mg alloys.

关键词： Extrusion speed Microstructure Mechanical properties Mg-Ca alloy

市场化进程下二元经济结构对城乡居民收入差距的影响分析

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经济问题探索 2019年第12期 102-111页

作者：曾卓然四川大学经济学院

文章选取2008-2017年省级面板数据研究了市场化进程、二元经济结构对我国城乡居民收入差距的影响。结果显示:市场化水平的提高和二元经济结构的改善均明显抑制我国城乡居民收入差距的不断扩大的趋势,但二者交互项对我国城乡居民收入差... 详细信息

文章选取2008-2017年省级面板数据研究了市场化进程、二元经济结构对我国城乡居民收入差距的影响。结果显示:市场化水平的提高和二元经济结构的改善均明显抑制我国城乡居民收入差距的不断扩大的趋势,但二者交互项对我国城乡居民收入差距却呈现出显著的正向助推作用,说明在推动市场化发展和改善二元经济结构时应注重对二者的统筹与协调。通过划分东部、中部和西部三个地区进行区域间比较分析,发现市场化进程的推进对中、西部地区影响效果大于东部地区,而二元经济结构对我国城乡居民收入差距的影响在东部和西部地区呈现显著的负向效应,在中部地区呈现不显著的正向效应。通过门限面板回归,发现二者对我国城乡居民收入差距的影响均存在显著的单重门限效应,但负向效应在门限内外影响趋势却不一致。

关键词：市场化进程二元经济结构收入差距

Decompression alone versus decompression with instrumented fusion for young patients with single-level lumbar disc herniation：a short-term prospective comparative study

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Chinese Medical Journal 2014年第11期127卷 2037-2042页

作者： Sun zhuoran Li Weishi Chen Zhongqiang Guo Zhaoqing Qi Qiang zeng Yan Sun Chuiguo Department of Orthopaedics Peking University Third Hospital Beijing 100191 China

Background For young patients,the surgical method for lumbar disc herniation remains controversial.The aim of this study was to prospectively determine the short-term clinical outcome after surgery for young patients with lumbar disc herniation.Methods In this prospective comparative study between April 2010 and August 2011,a total of 80 patients underwent primary surgery at a single level for lumbar disc herniation.The patients were divided into two groups：decompression alone and decompression with instrumented fusion.An independent examiner clinically evaluated the patients at preoperation and at 1,3,6,and 12 months after surgery.The patients filled out the instruments for back and leg pain using a Visual Analog Scale （VAS）,Oswestry Low Back Pain Disability Questionnaire （ODI）,and Japanese Orthopaedic Association （JOA） scores.The differences between the two groups were analyzed.Results The mean age of all the patients at the time of surgery was 33.7 years.Of the 80 patients,38 patients underwent decompression alone and 42 patients underwent posterior lumbar interbody fusion.Increasing complexity of surgery was associated with a longer surgery time,greater blood loss,and a longer hospital stay after surgery.Both methods of surgery independently improved outcomes compared with baseline status based on VAS,ODI,and JOA scores （P 〈0.05）,and no significant differences were found between the two groups at most of the measuring points in time,although patients with decompression alone had a higher JOA score （P=0.016） and higher JOA recovery rate （P=0.010） at the 3-month follow-up.Conclusions The short-term results of our study showed that both methods of surgery obtained effective clinical outcomes,but decompression alone had some advantages （shorter surgery time,less blood loss,shorter hospital stay,and lower cost） compared with decompression with instrumented fusion.Young patients with decompression alone could achieve great physical function earlier.

关键词： young patients single level lumbar disc herniation decompression alone prospective study

电商平台与其入驻商家合作发放优惠券的最优策略及效益

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系统工程理论与实践 2023年第1期43卷 110-134页

作者：曾燕吴雪枫康俊卿陈卓然中山大学岭南学院广州510275 帝国理工学院伦敦SW72AZ

随着数字经济发展,电商平台与其入驻商家合作发放优惠券日益成为流行的营销方式,但同时也给电商平台和入驻商家的运营决策及其对应的经济效益分析增加了复杂性.本文构建理论模型研究了电商平台与其入驻商家合作发放优惠券的最优策略及... 详细信息

随着数字经济发展,电商平台与其入驻商家合作发放优惠券日益成为流行的营销方式,但同时也给电商平台和入驻商家的运营决策及其对应的经济效益分析增加了复杂性.本文构建理论模型研究了电商平台与其入驻商家合作发放优惠券的最优策略及其经济效益,并考虑了其与广告促销策略之间的相互作用.本文发现:1)电商平台可以通过降低平台抽佣比例、减少商家参与合作发放优惠券的费用或者扩大商家的平台销售渠道市场规模等方式促进入驻商家参与合作发放优惠券;2)电商平台加大广告投入以及提升合作发放优惠券承担比例将会提升入驻商家参与合作发放优惠券的积极性;3)入驻商家参与合作发放优惠券的意愿与其广告投入之间存在相互促进关系;4)当入驻商家广告预算较为宽松或其广告投入对平台渠道需求影响较大时,即入驻商家可以更多地依靠广告投入来提升平台渠道需求时,合作发放优惠券将会使得消费者的实付价格上升,损害消费者利益.本文为理解新兴的合作发放优惠券的经济效益提供了新视角和新见解.

关键词：电商平台入驻商家合作机制优惠券广告投入消费者利益

High-throughput synthesis of size-controlled Pt-based catalysts

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Particuology 2023年第12期83卷 232-240页

作者： zhuoran Deng Liqiang Zhao Daojian Cheng State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing100029China College of Information Science and Technology Beijing University of Chemical TechnologyBeijing100029China

Pt catalysts are commonly used for chemical reaction processes due to its high catalytic activity and selectivity.Notably,the size of metal particles often has a significant impact on the performance of the metal-loaded catalysts.Therefore,developing highly efficiently synthesis method for the size control of Pt catalysts has great development prospects and research value.In this study,high-throughput size tuning of Pt-based catalysts was achieved by carbonizing the carriers.The experimental and characterization results showed that the size of the loaded Pt nanoparticles varied with different concentrations of glucose solution during carriers carbonization process.The reduction of 4-nitrophenol as a template reaction indicated that the reaction rate constant of the catalyst is approximately linear with the size of Pt particles.Importantly,a laboratory-built high-throughput synthesis system was applied for the catalyst synthesis,which enhances the automation of the laboratory exploratory experiments and makes it possible to synthesize catalysts with controllable size in batches.

关键词： High-throughput synthesis Size modulation Pt-based catalysts 4-Nitrophenol reduction

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基于混合型学习的高职课程教学实践

无线互联科技 2019年第6期16卷 108-110页

作者：曾凌峰李卓然罗定职业技术学院广东罗定527200

随着网络技术在现代教育中的普及,越来越多的网络教育平台、媒介涌现在大家视野中,混合式教学模式应运而生,成为高职教育改革的重要方向。文章以现代教育技术专业的"计算机专业英语"课程为例,应用混合式教学模式进行课程设计,研究该模... 详细信息

随着网络技术在现代教育中的普及,越来越多的网络教育平台、媒介涌现在大家视野中,混合式教学模式应运而生,成为高职教育改革的重要方向。文章以现代教育技术专业的"计算机专业英语"课程为例,应用混合式教学模式进行课程设计,研究该模式在高职教学中的实践价值,通过调查问卷,数据统计分析该模式的优缺点及提出优化方案。

关键词：高职教育混合型学习现代教育技术