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Automatic Mesh Generation on a Regular Background Grid

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Journal of Computer science & Technology 2002年第6期17卷 882-887页

作者： LO s.h 刘剑飞 Department of Civil Engineering The University of Hong Kong Hong Kong P.R. China Department of Mechanics Peking University Beijing 100871 P.R. China

This paper presents an automatic mesh generation procedure on a 2D domain based on a regular background grid. The idea is to devise a robust mesh generation s.heme with equal emphasis on quality and efficiency. Instead of using a traditional regular rectangular grid, a mesh of equilateral triangles is employed to ensure triangular element of the best quality will be preserved in the interior of the domain. As for the boundary, it is to be generated by a node/segment insertion process. Nodes are inserted into the background mesh one by one following the sequence of the domain boundary. The local structure of the mesh is modified based on the Delaunay criterion with the introduction of each node. Those boundary segments, which are not produced in the phase of node insertion, will be recovered through a systematic element swap process. Two theorems will be presented and proved to set up the theoretical basic of the boundary recovery part. Examples will be presented to demonstrate the robustness and the quality of the mesh generated by the proposed technique.

关键词： mesh generation background grid triangular mesh boundary recovery

Effect of ECAP temperature on microstructure and mechanical properties of Al–Zn–Mg–Cu alloy

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Progress in Natural science:Materials International 2016年第2期26卷 182-191页

作者： M.h.shaeri M.shaeri M.Ebrahimi M.T.salehi s.h seyyedein Department of Metallurgy and Materials Engineering Engineering Faculty Imam Khomeini International University Department of Materials science and Engineering Sharif University of Technology Department of Mechanical Engineering University of Maragheh Department of Metallurgy and Materials Engineering Iran University of Science and Technology

The effect of equal channel angular pressing(ECAP) at different temperatures(room temperature, 120,150 and 180 °C) on microstructure and mechanical properties of Al-7075 solid solution alloy was investigated. Microstructure of the specimens was examined using orientation imaging microscopy,transmission electron microscopy as well as X-ray diffractometer, and mechanical properties were measured by Vickers microhardness and tensile tests. Microstructural investigations showed that after3 or 4 passes of ECAP, fi ne grains with average grain sizes in range of 300–1000 nm could be obtained at different ECAP temperatures. Increasing ECAP temperature from 120 to 180 °C caused a decrease in mechanical properties as a result of increasing grains and precipitates sizes, decreasing fraction of high angle boundaries and also transformation of η′ into η phase, while increasing ECAP temperature from RT to 120 °C leads to an increase in mechanical properties due to the formation of small η′ precipitates. so it can be concluded that ECAP process at 120 °C is the optimum process for attaining maximum mechanical properties. Quantitative estimates of various strengthening mechanisms revealed that the improvement of mechanical properties was mainly attributed to grain re fi nement strengthening, precipitation strengthening and dislocation strengthening.

关键词： Equal channel angular pressing Microstructure strengthening mechanisms Mechanical properties

Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI h.GhANDVAR E.JUMAEV s.KhATIR T.CUONG-LE s.hool of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and science Center for Engineering Application and Technology solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANsYs, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

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INVEsTIGATION OF LOW CYCLE FATIGUE BEhAVIOROF BUILDING sTRUCTURAL sTEELs UNDEREARThQUAKE LOADING

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Acta Metallurgica sinica(English Letters) 1997年第1期10卷 51-55页

作者： G.M sheng and s.h Gong(Department of Metallurgy and Materials Engineering, Chongqing University Chongqing 630044, China) Chongqing Univ Chongqing China

Based on the failure model of building structural steels under earthquake loading, the low cycle fatigue test at constant strain, the stochastical fatigue test under real earthquake load spectrum and the structural fatigue test are carried out. The experimental results show that microalloying of V Ti and Nb can improve the anti-seismic propersties of steel bars. In the high strain and shori life range, both the static strength and ductility of steels are very important to increasing the low cycle fatigue resistance of steels.

关键词： low cycle fatigue earthquake building structural steel microalloying

A Remark on the Existence of Positive solution for a Class of/p,q/-Laplacian Nonlinear system with Multiple Parameters and sign-Changing Weight

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Journal of Partial Differential Equations 2013年第2期26卷 99-106页

作者： RAsOULI s.h Department of Mathematics Faculty of Basic Sciences Babol University ofTechnology Babol Iran.

The paper deal with the existence of positive solution for the following （p, q ）-Laplacian nonlinear system

关键词： (p,q)-Laplacian nonlinear system multiple parameters sign-changing weight.

Reliability-based maintenance s.heduling of hydraulic system of rotary drilling machines

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International Journal of Mining science and Technology 2013年第5期23卷 771-775页

作者： Mohammad Javad Rahimdel Mohammad Ataei Reza Khalokakaei seyed hadi hoseinie Faculty of Mining Engineering Sahand University of Technology Faculty of Mining Engineering Geophysics and PetroleumShahrood University of Technology Division of Operation and Maintenance Engineering Lulea University of Technology

hydraulic system has a critical and important role in drilling *** failure in this system leads to problems in power system and machine *** the failure cannot be prevented entirely,it is important to minimize its *** is one of the most effcient and important method to study safe operation probability of hydraulic *** this research,the reliability of hydraulic system of four rotary drilling machines in sarcheshmeh Copper Mine in Iran has been *** data analysis shows that the time between failures(TBF)of Machines A and C obey the Weibull(2P)and Weibull(3P)distribution,***,the TBF of Machines B and D obey the lognormal *** regard to reliability plots of hydraulic systems,preventive reliability-based maintenance time intervals for 80%reliability levels for machines in this system are 10 h.

关键词： Reliability Drilling hydraulic Maintenance

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摆渡红尘——小析影片《情欲写真》

电影文学 2002年第8期 21-22页

作者： s.h

年轻又多才多艺的女摄影师克莱丽对自己的生命、工作充满热情,无意间被加拿大报业龙头牵连至一件丑闻案中。

关键词：《情欲写真》电影艺术法国影片介绍故事情节主创人员

Dynamic stress concentration in an infinitely long cylindrical cavity due to a point s.herical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 139-156页

作者： h.hOssEINI O.BALILAshAKI Department of Mechanical Engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident s.herical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

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Neuroinflammation as a therapeutic target in huntington's disease

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Neural Regeneration Research 2025年第3期20卷 817-818页

作者： Andrea Kwakowsky Thulani h.Palpagama Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CentreUniversity of GalwayGalwayIreland

In 1872, George huntington presented his essay “On Chorea” to the Meigs and Mason Academy of Medicine and, in doing so, detailed a disease that would later bear his name. huntington's disease(hD) is a genetic, neurodegenerative disease that manifests as the loss of motor control,cognitive impairment,and mood and psychiatric changes in paents.

关键词： huntington inflammation Medicine