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Localized Method of Fundamental Solutions for Acoustic Analysis Inside a Car Cavity with Sound-Absorbing Material

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Advances in Applied Mathematics and Mechanics 2023年第1期15卷 182-201页

作者： zengtao chen Fajie Wang College of Mechanical and Electrical Engineering National Engineering Research Center for Intelligent Electrical Vehicle Power SystemQingdao UniversityQingdaoShandong 266071China Institute of Mechanics for Multifunctional Materials and Structures Qingdao UniversityQingdaoShandong 266071China

This paper documents the first attempt to apply a localized method of fundamental solutions(LMFS)to the acoustic analysis of car cavity containing soundabsorbing *** LMFS is a recently developed meshless approach with the merits of being mathematically simple,numerically accurate,and requiring less computer time and *** with the traditional method of fundamental solutions(MFS)with a full interpolation matrix,the LMFS can obtain a sparse banded linear algebraic system,and can circumvent the perplexing issue of fictitious boundary encountered in the MFS for complex solution *** the LMFS,only circular or spherical fictitious boundary is *** on these advantages,the method can be regarded as a competitive alternative to the standard method,especially for high-dimensional and large-scale *** benchmark numerical examples are provided to verify the effectiveness and performance of the present method for the solution of car cavity acoustic problems with impedance conditions.

关键词： Acoustic analysis localized method of fundamental solutions car cavity soundabsorbing material

An Uncertainty Analysis Method for Artillery Dynamics with Hybrid Stochastic and Interval Parameters

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Computer Modeling in Engineering & Sciences 2021年第2期126卷 479-503页

作者： Liqun Wang zengtao chen Guolai Yang School of Mechanical Engineering Nanjing University of Science&TechnologyNanjing210094China Department of Mechanical Engineering University of AlbertaEdmontonT6G 1H9Canada

This paper proposes a non-intrusive uncertainty analysis method for artillery dynamics involving hybrid uncertainty using polynomial chaos expansion(PCE).The uncertainty parameters with sufficient information are regarded as stochastic variables,whereas the interval variables are used to treat the uncertainty parameters with limited stochastic *** this method,the PCE model is constructed through the Galerkin projection method,in which the sparse grid strategy is used to generate the integral points and the corresponding integral *** the sampling in PCE,the original dynamic systems with hybrid stochastic and interval parameters can be transformed into deterministic dynamic systems,without changing their *** yielded PCE model is utilized as a computationally efficient,surrogate model,and the supremum and infimum of the dynamic responses over all time iteration steps can be easily approximated through Monte Carlo simulation and percentile difference.A numerical example and an artillery exterior ballistic dynamics model are used to illustrate the feasibility and efficiency of this *** numerical results indicate that the dynamic response bounds obtained by the PCE approach almost match the results of the direct Monte Carlo simulation,but the computational efficiency of the PCE approach is much higher than direct Monte Carlo ***,the proposed method also exhibits fine precision even in high-dimensional uncertainty analysis problems.

关键词： Uncertainty propagation and analysis artillery dynamics hybrid stochastic and interval uncertainty polynomial chaos expansion ordinary differential equations

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一种双流体喷头的微生物活性及喷雾特性

林业工程学报 2024年第3期9卷 138-148页

作者：李新松翟恩昱陈曾涛郑加强李建华南京林业大学机械电子工程学院南京210037 阿尔伯塔大学机械工程学院埃德蒙顿T6G 2R3

微生物农药比化学农药更加环保和安全,已成为农林病虫害生物防治的研究热点。然而,因为缺乏喷洒技术和专用设备,使微生物农药的应用受到制约。目前,传统的喷头仍然主要分为锥形雾和扇形雾喷头。由于扇形雾喷头的平面喷洒方式,配有该喷... 详细信息

微生物农药比化学农药更加环保和安全,已成为农林病虫害生物防治的研究热点。然而,因为缺乏喷洒技术和专用设备,使微生物农药的应用受到制约。目前,传统的喷头仍然主要分为锥形雾和扇形雾喷头。由于扇形雾喷头的平面喷洒方式,配有该喷头的喷雾机可用于大范围喷洒。与锥形雾喷头相比,扇形雾喷头喷洒后微生物农药的活性不能满足使用要求。为了保证微生物农药的活性,方便大范围喷洒并有良好的喷雾性能,研究了一种用于喷洒水和微生物农药混合物的双流体外混式扇形雾喷头。微生物农药的活性可以通过喷洒后微生物农药的活性(生存率R s)来评估。喷雾性能包括雾滴尺寸、分布均匀性和混合均匀性,并分别通过有效尺寸、变异系数(CV,式中记作C V)、均匀性变异系数(α)来评估。初步分析表明,在喷雾过程中,微生物农药与水的喷雾压力必须有一定的比值(λ),当λ为0.7∶0.2时,雾滴粒径在188~341μm的有效范围内,C V=0.40,α=0.47,R s=89.6%,可以保证微生物农药的活性,获得理想的喷雾特性。研究结果将为精确使用农药、大面积喷洒微生物农药并保证微生物农药活性,从而有效防治植物病虫害提供新的研究思路和方法。

关键词：水-农药双流体外混扇形雾喷头微生物农药的活性喷雾分布均匀性微生物农药的混合均匀性

Analytic solution for a circular nano-inhomogeneity in a finite matrix

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Nano Materials Science 2019年第2期1卷 116-120页

作者： Shuang Wang zengtao chen Cunfa Gao State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Department of Mechanical Engineering University of Alberta Edmonton AB T6G 1H9 Canada

The Gurtin-Murdoch model has found wide applications in analyzing the mechanical behaviors of nanocomposites with surface/interface effect. In the existing literature, the matrix is usually assumed to be infinite and the surface/interface effect is considered only at the inhomogeneity-matrix interface. This assumption is indeed valid as the matrix is usually at macroscale rather than nanoscale. However, if the size of the matrix decreases to the nanoscale too, the surface/interface effect will have to be considered at the outer boundary of the matrix. In this paper, the plane deformation of a circular nano-inhomogeneity embedded inside a finite circular matrix (which implies the matrix is also at nanoscale) is investigated. The stress boundary conditions are given at the inhomogeneity-matrix interface and the outer boundary of the matrix by the G-M model. The analytic solution for the stress field is finally obtained through the complex variable method. The results show that the stress field inside the inhomogeneity is still uniform (size-dependent) when the surface/interface effect is considered. In addition, the stress field inside the bulk (including the inhomogeneity and the matrix) can be influenced not only by the size and elastic constant of the inhomogeneity, but also by those of the matrix.

关键词： Plane problem Nanoscale inhomogeneity Finite matrix Surface/interface effect Complex variable methods

Localized MFS for three‐dimensional acoustic inverse problems on complicated domains

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International Journal of Mechanical System Dynamics 2022年第1期2卷 143-152页

作者： zengtao chen Fajie Wang Suifu cheng Guozheng Wu National Engineering Research Center for Intelligent Electrical Vehicle Power System College of Mechanical and Electrical EngineeringInstitute of Mechanics for Multifunctional Materials and StructuresQingdao UniversityQingdaoChina

This paper proposes a semi‐analytical and local meshless collocation method,the loca-lized method of fundamental solutions(LMFS),to address three‐dimensional(3D)acoustic inverse problems in complex *** proposed approach is a recently developed numerical scheme with the potential of being mathematically simple,nu-merically accurate,and requiring less computational time and *** LMFS,an overdetermined sparse linear system is constructed by using the known data at the nodes on the accessible boundary and by making the remaining nodes satisfy the governing *** the numerical procedure,the pseudoinverse of a matrix is solved via the truncated singular value decomposition,and thus the regularization techniques are not needed in solving the resulting linear system with a well‐conditioned *** experiments,involving complicated geometry and the high noise level,confirm the ef-fectiveness and performance of the LMFS for solving 3D acoustic inverse problems.

关键词： acoustic inverse problems localized method of fundamental solutions 3D Helmholtz equation meshless method inverse Cauchy problem

磁-电-弹性半空间在轴对称热载荷作用下的三维问题研究

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力学学报 2020年第5期52卷 1235-1244,I0001页

作者：胡克强高存法仲政 chen zengtao 南京航空航天大学机械结构强度与振动国家重点实验室南京210016 哈尔滨工业大学(深圳)理学院深圳518055 Department of Mechanical Engineering University of AlbertaEdmontonABT6G 2G8Canada

考虑力-电-磁-热等多场耦合作用,基于线性理论给出了磁-电-弹性半空间在表面轴对称温度载荷作用下的热-磁-电-弹性分析,并得到了问题的解析解.利用Hankel积分变换法求解了磁-电-弹性材料中的热传导及控制方程,讨论了在磁-电-弹性半空间... 详细信息

考虑力-电-磁-热等多场耦合作用,基于线性理论给出了磁-电-弹性半空间在表面轴对称温度载荷作用下的热-磁-电-弹性分析,并得到了问题的解析解.利用Hankel积分变换法求解了磁-电-弹性材料中的热传导及控制方程,讨论了在磁-电-弹性半空间在边界表面上作用局部热载荷时的混合边值问题,利用积分变换和积分方程技术,通过在边界表面上施加应力自由及磁-电开路条件,推导得到了磁-电-弹性半空间中位移、电势及磁势的积分形式的表达式.获得了磁-电-弹性半空间中温度场的解析表达式并且给出了应力,电位移和磁通量的解析解.数值计算结果表明温度载荷对磁-电-弹性场的分布有显著影响.当温度载荷作用的圆域半径增大时,最大正应力发生的位置会远离半无限大体的边界;反之当温度载荷作用的圆域半径减小时,最大应力发生的位置会靠近半无限大体的边界.电场和磁场在温度载荷作用的圆域内在边界表面附近有明显的强化,而磁-电-弹性场强化区域的强化程度跟温度载荷的大小和作用区域大小相关.本研究的相关结果对智能材料和结构在热载荷作用下的设计和制造具有指导意义.

关键词：磁-电-弹性材料轴对称温度载荷 Hankel变换热传导磁-电-弹性场

Formulation of international standards of Chinese medicine technology:clinical practice guide of Chinese medicine for cough

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Journal of Traditional Chinese Medicine 2024年第2期44卷 396-402页

作者： FANG Hanyu HONG Zheng LI Deming ZHANG Hongchun SHI Yihang LI Xiaojuan SUN zengtao chen Wei ZHANG Chuchu ZU Yaqi Beijing University of Chinese medicine Beijing 100029China Department of Traditional Chinese Medicine for Pulmonary Diseases Center of Respiratory MedicineChina-Japan Friendship HospitalBeijing 100029 National Center for Respiratory Medicine Beijing 100029China Department of Traditional Chinese Medicine for Pulmonary Diseases Center of Respiratory MedicineChina-Japan Friendship HospitalBeijing 100029China Tianjin University of Traditional Chinese Medicine Tianjin 301617China Second Teaching Hospital of Tianjin University of Traditional Chinese Medicine Tianjin 300250China Center for Evidence-based Medicine Beijing University of Chinese MedicineBeijing 100029China Institute of Information on Traditional Chinese Medicine China Academy of Chinese Medical SciencesBeijing 100700China

OBJECTIVE:To formulate the first clinical practice guideline for the treatment of cough using Chinese medicine based on the grading of recommendations assessment,development,and evaluation(GRADE)systematic approach,including clinical evidence,evaluation of ancient literature,and expert ***:In the process of development,the regulation of"evidence-based,consensus-assisted,and empirical"was followed,and a comprehensive systematic approach of recommendation assessment,GRADE,evidence-based evaluation,expert consensus,and the Delphi method was *** the process of guideline development,evidence-based evaluation of ancient literature was included for the first time,and clinical evidence was fully integrated with clinical expert ***:The clinical practice guidelines for the treatment of cough with Chinese herbal medicine were developed after a comprehensive consideration of evidence-based evaluation and expert *** guideline recommendations focused on recommending herbal compound decoctions and Chinese patent medicines for cough in different *** on the GRADE systematic approach,we conducted an evidence-based evaluation of the recommended Chinese patent medicines one by one;meanwhile,the expert consensus method was used to unify the recommendations of ***:Based on clinical evidence,ancient literature evaluation,and expert consensus,a clinical practice guideline for Traditional Chinese Medicine(TCM)in the treatment of cough was developed,providing the first current clinical practice guideline for domestic and foreign TCM and Western medicine practitioners,especially respiratory professionals at home and abroad.

关键词： Medicine Chinese Traditional clinical practice cough practice guide international standard

广义有限差分法在含阻抗边界空腔声学分析中的应用

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力学学报 2021年第4期53卷 1183-1195页

作者：陈增涛王发杰王超青岛大学动力集成及储能系统工程技术中心青岛大学机电工程学院山东青岛266071 青岛大学多功能材料与结构力学研究院山东青岛266071

声学分析在噪声控制、室内隔音等工程计算中有着重要的作用.由于现实生活中的声学模型往往伴随着吸声材料,因此分析含阻抗边界条件的声学问题显得十分必要.广义有限差分法是一种新型区域型无网格数值离散方法,该方法基于多元函数泰勒级... 详细信息

声学分析在噪声控制、室内隔音等工程计算中有着重要的作用.由于现实生活中的声学模型往往伴随着吸声材料,因此分析含阻抗边界条件的声学问题显得十分必要.广义有限差分法是一种新型区域型无网格数值离散方法,该方法基于多元函数泰勒级数展开式和加权最小二乘拟合,将控制方程中未知参量的各阶偏导数表示为相邻节点函数值的线性组合.本文首次将广义有限差分法应用于含阻抗边界条件空腔声学问题的分析中,建立了空腔声场问题的广义有限差分法数值离散格式.与传统算法相比,所建立的数值模型具有无需网格剖分和数值积分、计算精度高、适用于大规模声学分析等优点.通过具有解析解的经典算例,研究了总节点数目和局部支撑点数目对数值结果的影响,得到了最大计算频率与节点间距之间关系的经验公式.此外,将广义有限差分法应用于无解析解的二维和三维复杂声学模型,并与COMSOL Multiphysics软件所得的有限元结果进行了比较分析.数值实验表明,该算法是一种高效、精确、稳定、收敛的数值模拟方法,在含阻抗边界空腔声学分析中具有广阔的应用前景.

关键词：无网格法广义有限差分法空腔声学问题阻抗边界有限元法

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山东诸城地区下白垩统一新类型鸟类足迹

地质论评 2024年第2期70卷 411-416页

作者：张艳霞孙业君陈军崔卫生陈树清王增涛诸城市恐龙文化研究中心山东诸城262200 山东省地质科学研究院济南250013

1931年,Mehl报道的来自Dakota Group的Ignotornis mcconnelli是第一个被广泛接受的中生代鸟类足迹。目前,亚洲、北美洲、欧洲、非洲和南美洲都有白垩纪鸟类足迹的报道,尤其以东亚地区最为丰富。山东诸城张祝河湾恐龙足迹点保存了一枚完... 详细信息

1931年,Mehl报道的来自Dakota Group的Ignotornis mcconnelli是第一个被广泛接受的中生代鸟类足迹。目前,亚洲、北美洲、欧洲、非洲和南美洲都有白垩纪鸟类足迹的报道,尤其以东亚地区最为丰富。山东诸城张祝河湾恐龙足迹点保存了一枚完整的鸟类足迹,笔者等对该鸟类足迹进行了详细描述与对比。研究认为,该鸟类足迹区别于以往发现的鸟类足迹,根据其形态建立了新种:玲珑诸城鸟足迹Zhuchengornipes exquisitus。玲珑诸城鸟足迹造迹者可能为滨鸟类,形成于干旱气候下的滨浅湖环境。

关键词：诸城下白垩统鸟类足迹滨鸟类