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Thermal stress concentration points and stress mutations in nano-multilayer film structures

Communications in Theoretical Physics 2025年第1期77卷 179-189页

作者： Ying Zheng Zhi you Wang Qianju Song Zao Yi Shubo Cheng Can Ma Chaojun Tang qingdong Zeng Sohail Ahmad School of Mathematics and Science Joint Laboratory for Extreme Conditions Matter PropertiesThe State Key Laboratory of Environment-friendly Energy MaterialsTianfu Institute of Research and InnovationSouthwest University of Science and TechnologyMianyang 621010China School of Electronic Information and Electric Engineering Changsha UniversityChangsha 410022China School of Physics and Optoelectronic Engineering Yangtze UniversityJingzhouHubei 434023China School of Chemistry and Chemical Engineering Jishou UniversityJishou 416000China Department of Oncology Sichuan Science City HospitalMianyangSichuan Province 621000China College of Science Zhejiang University of TechnologyHangzhou 310023China School of Physics and Electronic-information Engineering Hubei Engineering UniversityXiaogan 432000China Institute of Physics Bahauddin Zakariya UniversityMultan66000Pakistan

In the multilayer film-substrate system,thermal stress concentration and stress mutations cause film buckling,delamination and cracking,leading to device *** this paper,we investigated a multilayer film system composed of a substrate and three film *** thermal stress distribution inside the structure was calculated by the finite element method,revealing significant thermal stress differences between the *** is mainly due to the mismatch of the coefficient of thermal expansion between *** materials respond differently to changes in external temperature,leading to compression between *** are obvious thermal stress concentration points at the corners of the base layer and the transition layer,which is due to the sudden change of the shape at the geometric section of the structure,resulting in a sudden increase in local *** address this issue,we chamfered the substrate and added an intermediate layer between the substrate and the transition layer to assess whether these modifications could reduce or eliminate the thermal stress concentration points and extend the service life of the multilayer *** results indicate that chamfering and adding the intermediate layer effectively reduce stress discontinuities and mitigate thermal stress concentration points,thereby improving interlayer bonding strength.

关键词： multilayer structure thermal stress concentration point stress mutation chamfer intermediate layer

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Design,synthesis and biological activities of histone deacetylase inhibitors with new zinc binding group

Design,synthesis and biological activities of histone deacet...

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2012长三角药物化学研讨会

作者： Feng Taotao Lu Hui Su Hong Yang Bo you qingdong Department of Medicinal Chemistry China Pharmaceutical University Department of Pharmacology School of Pharmaceutical ScienceZhejiang University

Histone deacetylases(HDACs) inhibition causes hyperacetylation of histones leading to apoptosis of tumor *** apoptotic effects have been linked to the modulation in the expression of several regulatory tumor suppressor genes caused by the modified status of histone acetylation,a key event in chromatin *** of previously reported HDACs inhibitors are hydroxamic acid derivatives, which could chelate the zinc ion in the active site in a bidentate ***,hydroxamic acids occasionally have produced problems such as poor pharmacokinetics,severe toxicity and low selectivity.

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Nonlinear free vibration of spinning cylindrical shells with arbitrary boundary conditions

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Applied Mathematics and Mechanics(English Edition) 2022年第8期43卷 1203-1218页

作者： qingdong CHAI Yanqing WANG Meiwen TENG Key Laboratory of Structural Dynamics of Liaoning Province College of SciencesNortheastern UniversityShenyang110819China Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang110819China

The aim of the present study is to investigate the nonlinear free vibration of spinning cylindrical shells under spinning and arbitrary boundary *** springs are used to simulate arbitrary boundary ***’shell theory is employed,and von Kármán nonlinear terms are considered in the theoretical *** using Chebyshev polynomials as admissible functions,motion equations are derived with the Ritz ***,a direct iteration method is used to obtain the nonlinear vibration *** effects of the circumferential wave number,the boundary spring stiffness,and the spinning speed on the nonlinear vibration characteristics of the shells are *** is found that there exist sensitive intervals for the boundary spring stiffness,which makes the variation of the nonlinear frequency ratio more *** decline of the frequency ratio caused by the spinning speed is more significant for the higher vibration amplitude and the smaller boundary spring stiffness.

关键词： spinning cylindrical shell nonlinear free vibration arbitrary boundary condition Chebyshev polynomial Sanders’shell theory

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Long-range asymmetric Cherenkov radiation

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 170-171页

作者： Gang Zhong qingdong Ou Macao Institute of Materials Science and Engineering(MIMSE) Faculty of Innovation EngineeringMacao University of Science and TechnologyTaipaMacao 999078China

Cherenkov radiation(CR)is gaining increasing attention as a high-output power Terahertz radiation source,and it plays a significant role in particle detectors,accelerators,and space science[1].This captivating phenomenon was first observed by Cerenkov in 1934 and was later explained theoretically by Tamm and Frank in 1937,earning them the Nobel Prize in Physics in *** occurs when charged particles move faster than the phase velocity of light in a specific medium.

关键词： asymmetric faster explained

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大气边界层中风力机载荷及功率特性的实验研究

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太阳能学报 2025年第1期46卷 9-16页

作者：郭兴铎李银然李仁年魏魁马清东兰州理工大学能源与动力工程学院兰州730050 甘肃省风力机工程技术研究中心兰州730050

该文在风洞中构建出两种平均风切变指数和湍流强度的大气边界层风场,并开展均匀来流和大气边界层条件下风力机载荷及功率特性的实验研究。结果表明:风力机偏航运行时,机组轴向载荷减小,疲劳载荷增大,随着偏航角增大,风轮功率系数减小,... 详细信息

该文在风洞中构建出两种平均风切变指数和湍流强度的大气边界层风场,并开展均匀来流和大气边界层条件下风力机载荷及功率特性的实验研究。结果表明:风力机偏航运行时,机组轴向载荷减小,疲劳载荷增大,随着偏航角增大,风轮功率系数减小,最优叶尖速比降低。在大气边界层来流条件下,风轮平均倾覆力矩系数和功率系数较均匀来流增大,机组疲劳载荷、极端载荷,及输出功率的非定常特性显著增加,且功率系数的概率分布更符合高斯分布。此外,风轮功率系数频谱与大气边界层来流速度频谱存在一定程度的关联性,在耦合区间出现Φ_(p)/Φ_(u)-f^(-2)的幂率关系。而功率系数频谱在超过约3倍转频后基本维持水平趋势,表明湍流来流与输出功率的调制作用在该频率处开始解耦,解耦后风力机功率输出受湍流来流的影响较弱,其功率谱响应主要取决于风轮的自身特性。

关键词：水平轴风力机大气边界层湍流功率载荷风洞实验

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基于狄拉克半金属纳米线的太赫兹可调七波段完美吸收器的模拟仿真

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物理学报 2025年第3期74卷 108-117页

作者：卢文强易颖婷宋前举周自刚易有根曾庆栋易早西南科技大学数理学院绵阳621010 中南大学物理学院长沙410083 湖北工程学院物理与电子信息工程学院孝感432000 吉首大学化学化工学院吉首416000

设计了一种高灵敏度、高品质因子、高品质因数、高频探测、双固定功能的太赫兹可调完美吸收器.该吸收器可实现4—14.5 THz范围内7个波段的完美吸收.在进行结构设计时将线阵结构的参数与周期进行了关联.通过计算吸收器的相对阻抗来对器... 详细信息

设计了一种高灵敏度、高品质因子、高品质因数、高频探测、双固定功能的太赫兹可调完美吸收器.该吸收器可实现4—14.5 THz范围内7个波段的完美吸收.在进行结构设计时将线阵结构的参数与周期进行了关联.通过计算吸收器的相对阻抗来对器件宏观层面的电磁进行解释,并通过分析共振频率点的表面电场和磁场分布,来分析该器件的物理机制.计算了7个共振频点的品质因子Q,其中最大Q值为219.41.通过改变外部折射率,该吸收器的灵敏度和品质因数值最大可达5421.43 GHz/RIU和35.204 RIU-1.通过讨论关键参数对器件的影响,得出该器件可实现双固定性能的选择、七波段吸收以及全波段反射.通过改变狄拉克半金属的费米能级,证明该吸收器具有良好的动态调节能力.通过改变外部电磁波的入射角发现该器件在中低频段具有良好的稳定性,但在高频段受外部入射角影响较大.本文所提出的吸收器在成像、探测、检测等领域具有巨大的应用潜力,相关工作对光电器件的设计提供了思路.

关键词：超材料太赫兹狄拉克半金属电磁多频吸收 Fano谐振可调

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CFD simulations for longwall gas drainage design optimisation

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International Journal of Mining Science and Technology 2017年第5期27卷 777-782页

作者： Qin Johnny Qu qingdong Guo Hua Coal Mining Research Program The Commonwealth Scientific and Industrial Research Organisation(CSIRO)Brisbane 883Australia

Computational fluid dynamics(CFD) simulation is an effective approach to develop and optimise gas drainage design for underground longwall coal mining. As part of the project supported by the Australian Government Coal Mining Abatement Technology Support Package(CMATSP), threedimensional CFD simulations were conducted to test and optimise a conceptual design which proposes using horizontal boreholes to replace vertical boreholes at an underground coal mine in *** performance between a vertical borehole and a horizontal borehole was first carried out to compare their capacity and effectiveness. Then a series of cases with different horizontal borehole designs were simulated to optimise borehole configuration parameters such as location, diameter, and number of boreholes. The study shows that the horizontal borehole is able to create low pressure sinks that protect the workings from goaf gas ingresses by changing goaf gas flow directions, and that it has the advantage to continuously maintain such low pressure sinks near the tailgate as the longwall advances. An example of optimising horizontal borehole locations in the longwall lateral direction is also given in this paper.

关键词： Goaf gas drainage Horizontal borehole CFD simulation Design optimisation Mining abatement technology

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High-resolution Transmission Electron Microscopy Characterization of the Structure of Cu Precipitate in a Thermal-aged Multicomponent Steel

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Chinese Journal of Mechanical Engineering 2019年第5期32卷 117-124页

作者： Lizhan Han qingdong Liu Jianfeng Gu Institute of Materials Modification and Modelling School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai Jiao Tong UniversityShanghai 200240China

High-dispersed nanoscale Cu precipitates often contribute to extremely high strength due to precipitation hardening,and whereas usually lead to degraded toughness for especially ferritic ***,it is important to understand the formation behaviors of the Cu ***-resolution transmission electron microscopy(TEM)is utilized to investigate the structure of Cu precipitates thermally formed in a high-strength low-alloy(HSLA)*** Cu precipitates were generally formed from solid solution and at the crystallographic defects such as martensite lath boundaries and *** Cu precipitates in the same aging condition have various structure of BCC,9 R and FCC,and the structural evolution does not greatly correlate with the actual *** presence of different structures in an individual Cu precipitate is observed,which reflects the structural transformation occurring locally to relax the strain *** multiply additions in the steel possibly make the Cu precipitation more complex compared to the binary or the ternary Fe-Cu alloys with Ni or Mn *** research gives constructive suggestions on alloying design of Cu-bearing alloy steels.

关键词： Cu precipitate High-resolution transmission electron microscopy Thermal aging High-strength low-alloy steel

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A unified gas-kinetic scheme for multiscale and multicomponent flow transport

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Applied Mathematics and Mechanics(English Edition) 2019年第3期40卷 355-372页

作者： Tianbai XIAO Kun XU qingdong CAI Department of Mechanics and Engineering Science College of EngineeringPeking University Department of Mathematics Hong Kong University of Science and Technology Department of Mechanical and Aerospace Engineering Hong Kong University of Science and Technology Shenzhen Research Institute Hong Kong University of Science and Technology

Compressible flows exhibit a diverse set of behaviors, where individual particle transports and their collective dynamics play different roles at different scales. At the same time, the atmosphere is composed of different components that require additional degrees of freedom for representation in computational fluid dynamics. It is challenging to construct an accurate and efficient numerical algorithm to faithfully represent multiscale flow physics across different regimes. In this paper, a unified gas-kinetic scheme(UGKS) is developed to study non-equilibrium multicomponent gaseous flows. Based on the Boltzmann kinetic equation, an analytical space-time evolving solution is used to construct the discretized equations of gas dynamics directly according to cell size and scales of time steps, i.e., the so-called direct modeling method. With the variation in the ratio of the numerical time step to the local particle collision time(or the cell size to the local particle mean free path), the UGKS automatically recovers all scale-dependent flows over the given domain and provides a continuous spectrum of the gas dynamics. The performance of the proposed unified scheme is fully validated through numerical *** UGKS can be a valuable tool to study multiscale and multicomponent flow physics.

关键词： unified gas-kinetic scheme(UGKS) multiscale modeling multicomponent flow

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Neural network as a function approximator and its application in solving differential equations

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Applied Mathematics and Mechanics(English Edition) 2019年第2期40卷 237-248页

作者： Zeyu LIU Yantao YANG qingdong CAI State Key Laboratory for Turbulence and Complex System Peking University Department of Mechanics and Engineering Science College of EngineeringPeking University Center for Applied Physics and Technology College of EngineeringPeking University

A neural network(NN) is a powerful tool for approximating bounded continuous functions in machine learning. The NN provides a framework for numerically solving ordinary differential equations(ODEs) and partial differential equations(PDEs)combined with the automatic differentiation(AD) technique. In this work, we explore the use of NN for the function approximation and propose a universal solver for ODEs and PDEs. The solver is tested for initial value problems and boundary value problems of ODEs, and the results exhibit high accuracy for not only the unknown functions but also their derivatives. The same strategy can be used to construct a PDE solver based on collocation points instead of a mesh, which is tested with the Burgers equation and the heat equation(i.e., the Laplace equation).

关键词： neural network(NN) function approximation ordinary differential equation(ODE)solver partial differential equation(PDE)solver

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