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AGING PRECIPITATION OF Cu-Zr AND Cu-Zr-Si ALLOYS AND AFFECTED BY COLD WORKING

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Acta Metallurgica Sinica(English Letters) 1990年第3期3卷 222-225页

作者： dong zhili TANG Xiangyun Tsinghua University,Beijing,ChinaHORI Sgigenori FUJITANI Wataru Faculty of Engineering,Osaka University,Japan dong zhili Dept.of Material Science and Engineering,Tsinghua University,Beijing 100084,China

The hardness and electrical conductivity of Cu-Zr and Cu-Zr-Si alloys varying with differ- ent aging regimes were measured and the factors influencing the electrical conductivity were *** is believed that a little Si can refine the precipitates and improve the resistance to *** improvement of materials properties by aging and the effect of cold work were also discussed.

关键词： aging precipitation Cu-Zr alloy

Elucidation of thermally induced internal porosity in zinc oxide nanorods

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Nano Research 2018年第5期11卷 2412-2423页

作者： Albertus D. Handoko Laura-Lynn Liew Ming Lin Gopinathan Sankar Yonghua Du Haibin Su zhili dong Gregory K. L. Goh Institute of Materials Research and Engineering Agency for Science Technology and Research (A＊STAR) Singapore 138634 Singapore School of Materials Science and Engineering Nanyang Technological University Singapore 639798 Singapore Department of Chemistry University College London London WC1H0AJ UK Institute of Chemical and Engineering Sciences Agency for Science Technology and Research (A＊STAR) Singapore 627833 Singapore

In situ electron microscopy, tomography, photoluminescence, and X-ray absorption spectroscopy were utilized to monitor and explain the formation and growth of internal pores within ZnO nanorods. Careful examination using electron microscopy and tomography indicate that nanosized intemal pores start appearing within the individual solution-grown ZnO nanorods upon exposure to 200 ℃. The pore volume growth rate is proportional to the heat treatment time, indicating that the process is diffusion controlled, akin to a reverse Ostwald ripening-like process. A manageable pore growth rate of 1.4-4.4 nm^3·min^-1 was observed at 540 ℃, suggesting that the effective control over internal porosity can be achieved by carefully controlling the heat-treatment profile. Mechanistic studies using X-ray absorption spectroscopy indicated that the pore formation is linked to the significant reduction of the number of zinc vacancies after heat treatment. An optimum condition exists where most of the native surface defects are removed, while the bulk defects are contained within the internal pores. It is also demonstrated that the internal porosity can be exploited to improve the visible light absorption of ZnO. A combination of the lower defect density and improved light absorption of the heat-treated ZnO films thus lead to an increase in the photo- electrochemical response of more than 20× compared to that of the as-grown ZnO.

关键词： zinc oxide solution growth hydrothermal porosity photocatalysis photocurrent

Highly Efficient and Stable Hydrogen Production in All pH Range by Two-Dimensional Structured Metal-Doped Tungsten Semicarbides

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Research 2019年第1期2019卷 991-1004页

作者： Edison H.Ang Khang N.Dinh Xiaoli Sun Ying Huang Jun Yang zhili dong Xiaochen dong Wei Huang Zhiguo Wang Hua Zhang Qingyu Yan Energy Research Institute Interdisciplinary Graduate SchoolNanyang Technological University637553Singapore Centre for Programmable Materials School of Materials Science and EngineeringNanyang Technological University639798Singapore Institute of Advanced Materials Nanjing Tech UniversityNanjing 210000China School of Physical Electronics University of Electronic Science and Technology of ChinaChengdu 610054China Department of Chemistry City University of Hong KongKowloonHong Kong

Transition-metal-doped tungsten semicarbide nanosheets(M-doped W_(2)C NSs,M=Fe,Co,and Ni)have been synthesized through carburization of the mixture of tungsten trioxide,polyvinylpyrrolidone,and metal *** nanosheets grow directly on the W mesh and have the lateral dimension of several hundreds of nm to a few�m with a thickness of few tens *** is demonstrated that the M-doped W_(2)C NSs exhibit superior electrocatalytic activity for hydrogen evolution reaction(HER).Impressively,the Nidoped W_(2)C NSs(2 at%Ni)with the optimized HER activity show extremely low onset overpotentials of 4,9,and 19 mV and modest Tafel slopes of 39,51,and 87 mV dec−1 in acidic(pH=0),neutral(pH=7.2),and basic(pH=14)solutions,respectively,which is close to the commercial Pt/C *** functional theory(DFT)calculations also demonstrate that the Gibbs free energy for H adsorption of Ni-W_(2)C is much closer to the optimal valueG_(H∗)=-0.073 eV as compared to-0.16 eV of W_(2)***,nearly 100%Faradaic efciency and long-term stability are obtained in those *** realization of highly tolerant metal semicarbide catalyst performing on par with commercial Pt/C in all range of pH ofers a key step towards industrially electrochemical water splitting.

关键词： Highly closer realization

HIGH TEMPERATURE OXIDATION AND STRUCTURE OF SCALE AND WHISKERS FOR Fe-Ni-Cr SEALING ALLOYS

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Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 147-150页

作者： dong zhili MA Jusheng TANG Xiangyun YOU Liang Tsinghua University,Beijing,China lecturer Department of Materials Science and Engineering,Tsinghua University,Beijing 100084,China Tsinghua Univ Beijing China

The oxidation rate,the growth,morphology and structure of oxide scale and whiskers for Fe-Ni-Cr sealing alloys in H_2-H_2O atmosphere at high temperatures have been studied. The growth rate of scale is controlled by *... 详细信息

关键词： oxidation oxide scale oxide whisker Fe-Ni-Cr sealing alloy

Effect of Aging Parameters on Inconel 718 Fabricated by Laser Directed Energy Deposition

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Chinese Journal of Mechanical Engineering(Additive Manufacturing Frontiers) 2023年第4期2卷 112-121页

作者： Nataniel Yong Syn Tham Grace Rui Si Tay Bingqing Yao Kaiqiang Wu zhili dong School of Materials Science and Engineering Nanyang Technological UniversitySingapore639798Singapore Advanced Remanufacturing and Technology Center(ARTC) Agency for ScienceTechnology and Research(A∗STAR)Singapore637143Singapore School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore639798Singapore

Inconel 718 is a nickel-based superalloy of high interest in high temperature applications such as turbine *** be used in such applications,heat treatments are commonly applied to dissolute Laves phase and to achieve𝛾γ′***,conventional heat treatment methods for wrought Inconel 718 may not be suitable for Inconel 718 fabricated by laser directed energy deposition(LDED)due to its unique microstructure formed during the rapid solidification *** has been a lack of investigation in heat treatments for Inconel 718 fabricated by this process,specifically around the impact of aging parameters on this *** this study,the effects of aging parameters were studied by performing seven different heat treatments,including solutionising and aging *** results indicate that for LDED Inconel 718,a high temperature solution treatment of 1100℃for 1 h followed by single aging at 650℃for 20 h achieved a tensile strength and elongation of 1247 MPa and 23%,***,results indicated that even with a shorter aging time of 10 h,γ′phase was found to be of comparable size to the standard double aged treatment.

关键词： Inconel 718 Laser directed energy deposition Heat treatment Microstructure Additive manufacturing

PROCESS OF OXIDE FILM FORMATION ON JOINT INTERFACE OF METAL AND GLASS

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Transactions of Nonferrous Metals Society of China 1991年第1期1卷 66-72页

作者： Ma Jusheng Kaoru KOJIMA Masayosi TAKADA dong zhili Tang Xiangyun Tsinghua University Bey ing 100084China Sumitomo Special Matals Co.Osaka Japan

The *** oxide films on 476 alloy,with a small amount of additive elements such as Si etc.,oxidized in wet hydrogen atmosphere is some times accompanied by the formation of a great many *** form of whiskers grown on the oxide film is of flag pole type with a globe on its *** pole is a spinel single crysul oxide(Fe,Mn)Cr_(2)O_(4) and the globe is a metallic compound(Ni,Fe)_(x)Al_(y) covered with protective Al,Si oxide *** of the metallic globe named while particle is formed at the early stage of heating be tween 700℃ and 900℃.It seems to be extracted from the alloy matrix as a result of arummrum obrusion .Asial growth of pole begins at about 115℃.It is supposed that the whisker grows at the root of a white particle and the interaction effect between the stress of oxide around the particle and the climbing motion of dislocation beneath the *** the alloy surface is covered uniformly with Cr_(2)O_(3) as the ini tai oxide film,its final surface oxide film has no whiskers even after long time oxidation at higher temperature in hydrogen *** surface treatment of base alloy,such mechanical brushing,is very effective for the formation of Cr_(2)O_(3) at initial *** is supposed that the brushed surface may be activated to produce surface reactions by an enrichment of lattice defects.

关键词： sealing alloy oxide film oxide whisker

从奥巴马到特朗普:美国科技创新政策特点和趋势分析

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中国科技论坛 2017年第8期 168-174页

作者：董艳春徐治立霍宇同北京航空航天大学公共管理学院北京100191

科技创新政策是对一系列旨在推动科技发展策略措施的统称,既为科技发展指明战略方向也规划出具体战术路径。通过对奥巴马政府科技创新政策的研究,总结出其在政策制定战略、政策战术选择、政策目标定位等方面的特点。特朗普政府颁布的201... 详细信息

科技创新政策是对一系列旨在推动科技发展策略措施的统称,既为科技发展指明战略方向也规划出具体战术路径。通过对奥巴马政府科技创新政策的研究,总结出其在政策制定战略、政策战术选择、政策目标定位等方面的特点。特朗普政府颁布的2018财年预算蓝图,在一定程度上反映出新政府的科技发展规划,因此文章以其内容分析为基础,并通过与奥巴马时期进行比较,分析出特朗普时代美国科技创新政策呈现出的新特点和新趋势。

关键词：奥巴马特朗普预算科技创新政策

基于子模型技术的LISA中肘杆机构拓扑优化

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组合机床与自动化加工技术 2024年第9期 11-14页

作者：董世亮纪玉杰孙志礼沈阳理工大学机械工程学院沈阳110159 东北大学机械工程与自动化学院沈阳110819

激光干涉空间天线LISA(laser interferometer space antenna)作为空间引力波探测任务装备,其结构的轻量化设计是重要问题之一。基于子模型分析技术,采用固体各向同性材料惩罚(SIMP)模型插值变密度法,对LISA中肘杆机构的上下肘杆进行了... 详细信息

激光干涉空间天线LISA(laser interferometer space antenna)作为空间引力波探测任务装备,其结构的轻量化设计是重要问题之一。基于子模型分析技术,采用固体各向同性材料惩罚(SIMP)模型插值变密度法,对LISA中肘杆机构的上下肘杆进行了拓扑优化设计;将肘杆的应力作为约束条件,并以肘杆结构的柔度最小化和质量最小化为优化目标,构建肘杆拓扑优化的数学模型,得到了肘杆构件的最优拓扑结构。优化后的上下肘杆质量分别降低了41.89%和32.31%,且优化后的肘杆机构应力和位移均满足设计要求,为进一步设计和实验研究提供参考。

关键词： LISA 轻量化子模型变密度法拓扑优化

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产品数据交换标准STEP在建筑业中的进展

建筑科学 1999年第3期15卷 53-57页

作者：于少军董智力魏文郎中国建筑科学研究院计算中心

在当今的工业计算机应用中，产品信息的通讯、交换和共享存在严重问题，国际标准化组织ＩＳＯ为了解决这个问题，开发了国际产品数据交换标准ＳＴＥＰ。本文简述了ＳＴＥＰ的内容及其在建筑业中的发展。

关键词： STEP 集成资源产品信息交换建筑物单元