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Effect of a High Magnetic Field on the Shape of the γ' Precipitates in Cast Nickel-based Superalloy K52

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Journal of Materials Science & Technology 2009年第3期25卷 379-382页

作者： X. Ren G.Q. Chen w.L. Zhou C.w. wu C. Yuan J.S. Zhang State Key Laboratory of Materials Modification by Laser Ion and Electron Beams Dalian University of Technology Dalian 116085 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116085 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

The shape change of the γ＇ precipitates of cast Ni-based superalloy K52 after aging treatment under a high magnetic field was investigated. The results show that duplex γ＇ precipitates are present in the γ matrix after aging treatment with or without the magnetic field. One is the coarse particles with average size of 500 nm; the other is fine spherical γ＇ precipitates with average of 100 nm in diameter. The application of a 10T magnetic field only results in the shape of the coarse γ＇ particles changing from spherical to cuboidal when the alloys subjected to the same heat treatments. This shape change was mainly discussed based on the strain energy increase caused by the difference in magnetostriction between the γ matrix and γ＇ precipitates. The fine γ＇ particles still keep spherical. Further TEM observations shows that a number of γ particles in nano-scale precipitate in the coarse γ＇ particles in the specimens treated without the magnetic field. In addition, it was found that the magnetic field caused the decrease of the hardness in the alloy, and the hardness was associated with the field direction.

关键词： Ni-based superalloy High magnetic field Magnetostrictive strain energy Precipitation

Analyzing the Effects of Key Design Factors of a Negative-Differential-Resistance(NDR)Microfluidic Oscillator–an Equivalent-Circuit-Model Approach

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Advances in Applied Mathematics and Mechanics 2022年第6期14卷 1381-1399页

作者： J.w.wu H.M.Xia Z.P.wang w.wang H.J.Du School of Mechanical Engineering Nanjing University of Science and TechnologyNanjingJiangsu 210094China Singapore Institute of Manufacturing Technology 73 Nanyang DriveSingapore 637662Singapore School of Mechanical and Aerospace Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore

Numerical study on dynamic hydroelastic problems is usually rather complex due to the coupling of fluid and solid ***,we demonstrate that the performance of a hydroelastic microfluidic oscillator can be analyzed using a simple equivalent circuit *** studies reveal that its transition from the steady state to the oscillation state follows the negative-differential-resistance(NDR)*** performance is mainly determined by a bias fluidic resistor,and a pressurevariant resistor which further relates to the bending stiffness of the elastic diaphragm and the depth of the oscillation *** this work,a numerical study is conducted to examine the effects of key design factors on the device robustness,the applicable fluid viscosity,the flow rate,and the transition *** underlying physics is interpreted,providing a new perspective on hydroelastic oscillation *** findings also provide design guidelines of the NDR fluidic oscillator.

关键词： Microfluidic oscillator hydroelastics equivalent circuit model negative differential resistance

Symmetric Directional Coupler Optical Switch In GaAs

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光电子.激光 1989年第2期 100-102页

作者： Z. w. wu M.H. wangDepartment of Imformation Electronic EngineeringZhejiang University, HangZhou China

The GaAs homostructure symmetric waveguide and electrode diretional optical switch with Schottycontact has been analyzed and fabricated.

关键词： Symmetric Directional Coupler Optical Switch In GaAs In mode

A preliminary analysis of fishery resource exhaustion in the context of biodiversity decline

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Science China Earth Sciences 2016年第11期59卷 223-235页

作者： ZHAO ShuJiang Lü BaoQiang LI Ruwei ZHU AiYi wu Changwen School of Marine Science and Technology Zhejiang Ocean University Zhoushan 316022 China Marine Environmental Monitoring Central Station of wenzhou State Oceanic Administration People's Republic of China Wenzhou 325013 China

Marine biodiversity in almost all oceans is being threatened at the genetic, species, and ecosystem levels. The marine ecosystem is being degraded and the extinction rate of marine organisms has accelerated. In this paper, the potential causes of fishery resource exhaustion in the East China Sea are analyzed, including the change in the stoichiometric composition of seawater with regard to the concentrations of N and P, toxic effects of marine pollution, marine habitat destruction, increased seawater temperatures caused by climate warming, ocean acidification, pressure from overfishing, and the spread of marine pathogenic bacteria. It is believed that the factors mentioned above have significant impact on the exhaustion of fishery resources in the East China Sea. However, considering the cumulative, synergistic, and superimposed effects as well as the amplification effects resulting from their interactions, the actual risk of ecological extinction of marine organisms might be even more severe than that previously estimated. Hence, ecosystem management and research focused on a single risk factor or influencing factor is not enough to prevent marine ecosystem degradation and fishery resource exhaustion. A comprehensive, systematic, effective, and ecosystem-based management policy is imperative for healthy and sustainable fishery development in the East China Sea.

关键词： Fishery resources Exhaustion Extinction Influencing factor Cumulative effect Superimposed effect Amplifi-cation effect

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Single crystal growth, structural and transport properties of bad metal RhSb2

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Chinese Physics B 2020年第3期29卷 1-6页

作者： D S wu Y T Qian Z Y Liu w wu Y J Li S H Na Y T Shao P Zheng G Li J G Cheng H M weng J L Luo Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

we have successfully grown an arsenopyrite marcasite type RhSb2 single crystal, and systematically investigated its crystal structure, electrical transport, magnetic susceptibility, heat capacity, and thermodynamic properties. we found that the temperature-dependent resistivity exhibits a bad metal behavior with a board peak around 200 K. The magnetic susceptibility of RhSb2 shows diamagnetism from 300 K to 2 K. The low-temperature specific heat shows a metallic behavior with a quite small electronic specific-heat coefficient. No phase transition is observed in both specific heat and magnetic susceptibility data. The Hall resistivity measurements show that the conduction carriers are dominated by electrons with ne = 8.62 × 10^(18) cm^(-3) at 2 K, and the electron carrier density increases rapidly above 200 K without change sign. Combining with ab-initio band structure calculations, we showed that the unusual peak around 200 K in resistivity is related to the distinct electronic structure of RhSb_2. In addition, a large thermopower S(T) about -140 μV/K is observed around 200 K, which might be useful for future thermoelectric applications.

关键词： single crystal growth ab-initio band calculations susceptibility heat capacity thermodynamic transport properties

Single Crystal Growth and Magnetoresistivity of Topological Semimetal CoSi

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Chinese Physics Letters 2019年第7期36卷 77-81页

作者： D.S.wu Z.Y.Mi Y.J.Li w.wu P.L.Li Y.T.Song G.T.Liu G.Li J L.Luo Institute of Physics and Beijing National Laboratory for Condensed Matter Physics Chinese Academy of Sciences Beijing 100190 School of Physical Sciences University of Chinese Academy of Sciences Beijing 100190 Songshan Lake Materials Laboratory Dongguan 523808

we report single crystal growth of CoSi, which has recently been recognized as a new type of topological semimetal hosting fourfold and sixfold degenerate nodes. The Shubnikov–de Haas quantum oscillation(QO) is observed on our crystals. There are two frequencies originating from almost isotropic bulk electron Fermi surfaces, in accordance with band structure calculations. The effective mass, scattering rate, and QO phase difference of the two frequencies are extracted and discussed.

关键词： single crystal growth been recognized as extracted and discussed

Boundary element acoustics:fundamentals and computer codes

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基于四叉树网格近海海域波浪、潮流相互作用的数学模型

2000年

作者： editor T.w. wu

来源：畅想之星图书光盘版（南... 评论

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畅想之星图书光盘版（南通市图书馆镜像）

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中国科学：物理学、力学、天文学 2012年第3期42卷 294-309页

作者：张明亮 wu w.M. 大连海洋大学海洋科技与环境学院大连116023 National Center for Computational Hydroscience and Engineering The University of MississippiMS 38677USA

针对近海岸区域地形、水文、泥沙运动复杂的特点,本文建立了高效的近岸平面二维隐格式潮流、波浪联合作用的数值计算模式.水动力数值模型以非线性的浅水方程为基础,应用Quadtree非结构网格,变量布设采用同位网格,u,v及水位变量布设在同... 详细信息

针对近海岸区域地形、水文、泥沙运动复杂的特点,本文建立了高效的近岸平面二维隐格式潮流、波浪联合作用的数值计算模式.水动力数值模型以非线性的浅水方程为基础,应用Quadtree非结构网格,变量布设采用同位网格,u,v及水位变量布设在同一个节点上,简化计算程序的代码.采用有限体积方法离散方程,应用SIMPLEC程式求解离散的控制方程,由Rhie-Chow的动量插值方法计算界面通量可以避免棋盘式波动.整合的方程组采用最小残差法(GMRES)求解,并利用预条件的不完全Lu分解方法加速其收敛性、提高计算效率.波浪模型以考虑波浪折射、绕射、衍射以及波浪破碎影响的多向不规则波的波作用量守恒方程为基础,计算的波浪幅射应力反应波浪对水体的驱动力.将本文的耦合模型应用到稳态丁坝绕流、理想海湾、法国的Gironde Estuary、波生沿岸流和美国的Grays Harbor算例中,数值模拟结果分别和实验值及测量结果进行比较.计算结果表明,本文建立的平面二维波浪、潮流耦合的数值模型能够准确、高效的模拟复杂计算域的潮流及波浪问题,该模型对近海工程的顺利开展以及海岸带环境保护等方面具有重要的应用价值.

关键词：非结构化四叉树网格有限体积法隐格式波浪破碎波流相互作用

ATOMIC　FORCE　MICROSCOPY　OBSERVATION　OF　MAGNETRON　SPUTTERED　ALUMINUM－SILICON　ALLOY　FILMS

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Acta Metallurgica Sinica(English Letters) 1996年第4期9卷 263-266页

作者： J.w.wu,J.H. Fang and Z.H.Lu (National Laboratory of Molecule and Biomolecule Electronics,Southeast University,Nanjing 210096, China

wo different surface morphology characteristics of magnetron sputtered aluminumsilicon(Al-Si)alloy films deposited at 0 and 200℃ were observed by atomic force microscopy(AFM).One is irregularly shaped grains put togther on a *** other is irregularly shaped grains Piled up in space. Nanometer-sized particles with heights from 1.6 to 2.9 nm were first observed. On the basis of these observations the growth mechanism of magnetron sputtered films is discussed.

关键词： magnetron sputtering Al-Si alloy surface morphology,atomic force microscopy,film growth mechanism