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Nonlinear thermo-mechanical stability of eccentrically stiffened functionally graded material sandwich doubly curved shallow shells with general sigmoid law and power law according to third-order shear deformation theory

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Applied Mathematics and Mechanics(English Edition) 2017年第2期38卷 191-216页

作者： d.V.dUNG d.T.dONG Faculty of Mathematics Mechanics and Informatics Vietnam National University Hanoi 100000 Vietnam Faculty of Civil Engineering University of Transport Technology Hanoi 100000 Vietnam

In this paper, the nonlinear analysis of stability of functionally graded ma- terial （FGM） sandwich doubly curved shallow shells is studied under thermo-mechanical loads with material properties obeying the general sigmoid law and power law of four ma- terial models. Shells are reinforced by the FGM stiffeners and rest on elastic foundations. Theoretical formulations are derived by the third-order shear deformation theory （TSdT） with the von Karman-type nonlinearity taking into account the initial geometrical im- perfection and smeared stiffener technique. The explicit expressions for determining the critical buckling load and the post-buckling mechanical and thermal load-deflection curves are obtained by the Galerkin method. Two iterative algorithms are presented. The effects of the stiffeners, the thermal element, the distribution law of material, the initial imper- fection, the foundation, and the geometrical parameters on buckling and post-buckling of shells are investigated.

关键词： functionally graded material (FGM) sandwich double curved shallow shell,thermo-mechanical stability FGM stiffener elastic foundation

Pattern synthesis optimization of 3-d OdAR based on improved GA using LSFE method

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Journal of Harbin Institute of Technology(New Series) 2011年第1期18卷 96-100页

作者：龙伟军贲德 BAKHSHI ASIM d 张弓 College of Information Science and Technology Nanjing University of Aeronautics & Astronautics Computer Engineering University of Engineering and Technology

Pattern synthesis in 3-d opportunistic digital array radar(OdAR) becomes complex when a multitude of antennas are considered to be randomly distributed in a three dimensional *** order to obtain an optimal pattern,several freedoms must be constrained.A new pattern synthesis approach based on the improved genetic algorithm(GA) using the least square fitness estimation(LSFE) method is *** optimized by this method include antenna locations,stimulus states and phase *** new algorithm demonstrates that the fitness variation tendency of GA can be effectively predicted after several "eras" by the LSFE *** is shown that by comparing the variation of LSFE curve slope,the GA operator can be adaptively modified to avoid premature convergence of the *** validity of the algorithm is verified using computer implementation.

关键词： antenna radiation patterns genetic algorithm(GA) opportunistic digital array radar(OdAR) pattern synthesis the least square fitness estimation(LSFE)

Kinematic error modeling and error compensation of desktop 3d printer

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Nanotechnology and Precision Engineering 2018年第3期1卷 180-186页

作者： Shane Keaveney Pat Connolly Eoin d.O'Cearbhaill School of Mechanical and Materials Engineering UCD Engineering and Materials Science CentreDublin 4Ireland

desktop 3d printers have revolutionized how designers and makers prototype and manufacture certain *** popular fuse deposition modeling(FdM)desktop printers have enabled a shift to low-cost consumer goods markets,through reduced capital equipment investment and consumable material ***,with this drive to reduce costs,the computer numerical control(CNC)systems implemented in FdM printers are often compromised by poor accuracy and contouring *** condition is most critical as users begin to use 3d-printed components in load-bearing applications or to perform mechanical *** methods of low-cost 3d printer calibration are needed before their open-design potential can be realized in applications,including 3d-printed orthotics and *** paper applies methodologies associated with high-precision CNC machining systems,namely,kinematic error modeling and compensation coupled with standardized test methods from ISO230-4,such as the ballbar for kinematic and dynamic error measurements,to examine the influence and feasibility for use on low-cost CNC/3d printing ***,the *** and drug Administration's"Technical considerations for additive manufactured medical devices"highlighted the need to develop standards specific to additive manufacturing in regulated manufacturing *** paper shows the benefits of the methods described within ISO230-4 for error assessment,alongside applying kinematic error modeling and compensation to the popular kinematic configuration of an Ultimaker 3d printer.A Renishaw ballbar QC10 is used to quantify the Ultimaker's errors and thereby populate the error *** method quantifies machine errors and populates these in a mathematical model of the CNC ***,a post-processor can be used to compensate the printing ***,the ballbar is used to demonstrate the dramatic impact of the error compensation model on the accuracy and contouring of the Ultimaker pr

关键词： 3d printing accuracy Kinematic error modeling Kinematic error compensation Ballbar FdM3d printing ISO230-4

pde2path – A Matlab Package for Continuation and Bifurcation in 2d Elliptic Systems

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Numerical Mathematics(Theory,Methods and Applications) 2014年第1期7卷 58-106页

作者： Hannes Uecker daniel Wetzel Jens d.M.Rademacher Institut für Mathematik Universität Oldenburg26111 OldenburgGermany Universität Bremen Fachbereich MathematikPostfach 33044028359 BremenGermany

pde2path is a free and easy to use Matlab continuation/bifurcation package for elliptic systems of PdEs with arbitrary many components,on general two dimensional domains,and with rather general boundary *** package is based on the FEM of the Matlab pdetoolbox,and is explained by a number of examples,including Bratu’s problem,the Schnakenberg model,Rayleigh-Bénard convection,and von Karman plate *** serve as templates to study new problems,for which the user has to provide,via Matlab function files,a description of the geometry,the boundary conditions,the coefficients of the PdE,and a rough initial guess of a *** basic algorithm is a one parameter arclength-continuation with optional bifurcation detection and *** calculations,error control and mesh-handling,and some elementary timeintegration for the associated parabolic problem are also *** continuation,branch-switching,plotting etc are performed via Matlab command-line function calls guided by the AUTO *** software can be downloaded from ***/*** ker/pde2path,where also an online documentation of the software is provided such that in this paper we focus more on the mathematics and the example systems.

关键词： Elliptic systems continuation and bifurcation finite element method

Application and validation of a 3-d calcium,chloride,and sulfate model in Lake Okeechobee

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Ecological Processes 2014年第1期3卷 1-19页

作者： Kang-Ren Jin Mark d Shafer Zhen-Gang Ji Lead Scientist South Florida Water Management DistrictP.O.Box 24680West Palm BeachFL 33416-4680USA Senior Environmental Engineer US Army Corps Engineers701 San Marco BlvdJacksonvilleFL 32207-8175USA Adjunct Professor Department of Civil EngineeringCatholic University of AmericaPangborn HallRoom G12WashingtonDC 20064USA

Introduction: The calibration, verification, and validation of calcium (Ca), chloride (Cl), and sulfate (SO_(4)) module ofthe Lake Okeechobee Environment Model (LOEM) was completed. The integrated model could simulate Ca, Cl, andSO_(4) concentrations and transport due to wind driven currents and waves from 1 Oct 1999 to 30 Sept 2009 in LakeOkeechobee. The enhanced model was also used to estimate lake water quality effects resulting from differentmanagement scenarios that include discharges from planned aquifer storage and recovery (ASR) ***: The fate and transport processes of Ca, Cl, and SO_(4) are controlled by their reactivity and their hydrodynamictransport. Reactivity includes chemical, biological, and bio-uptake processes (IJRSA 33:2233-2260, 2012). Hydrodynamictransport includes advection of water current, diffusion, and turbulent mixing within the water column. The depositionand resuspension on the water-sediment bed interface is also included. The mathematical equations for describing Ca,Cl, and SO_(4) substances, including heavy metal and total organic carbon (TOC), are ***: Both the statistical results and the time series comparisons indicate that the simulation of Ca, Cl, and SO_(4) aregenerally simulated well by the LOEM. The root mean square error over the variance rage is Cl dSO_(4) d SO_(4) concentrations in the lake were largely controlled by water temperature and lakeevaporation. Inflows to the lake can also have localized effects on chloride variations. Shallow water depth and highevaporation contribute to high Cl/Ca/ SO_(4) concentration in the lake.

关键词： Ca Cl SO_(4)modeling Lake Okeechobee Long-term simulation Environmental modeling

Kinematics of whip spider pedipalps: a 3d comparative morpho-functional approach

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Integrative Zoology 2022年第1期17卷 156-167页

作者： Michel SCHMIdT Roland R.MELZER Russell d.C.BICKNELL Bavarian State Collection of Zoology Bavarian Natural History CollectionsMunichGermany department Biology II Ludwig-Maximilians-Universität MünchenMunichGermany GeoBio-Center Ludwig-Maximilians-Universität MünchenMunichGermany Palaeoscience Research Centre School of Environmental and Rural ScienceUniversity of New EnglandArmidaleAustralia

Amblypygi are tropical and subtropical ambush predators that use elongated,raptorial pedipalps for different *** pedipalp use in predation and courtship has been explored in videography in vivo analyses,kinematic ex vivo examination of these appendages has not been ***,we rectify this lack of data by using microCT scans to 3d-kinematically model the appendage morphology and the range of motion(ROM)of the joints for damon medius and Heterophrynus *** illustrate the successful application of this technique to terrestrial euarthropods in determining the maximum ROM values for each pedipalp *** also note that,in life,these values would be lower due to motion restricting structures like tendons,arthrodial membranes,and *** further compare our maximum values obtained here with data from video-based motion *** ROM of each joint shows the greatest flexibility in the femur-tibia joint(140–150°),the lowest in the basitarsus-claw joint(35–40°).ROM in the tibia-basitarsus joint is markedly distinct(***:44°;***:105°).This disparity reflects how *** uses the joint in the capture basket,while *** uses the femur-tibia joint to form the capture *** further illustrate notable vertical motion of the *** pedipalp compared to *** difference reflects the retro-ventral trochanter apophysis of *** study opens the possibility to further whip spider kinematic *** of other taxa using this approach will result in a more comprehensive understanding of the ecological significance and ethological implications of this unique arachnid group.

关键词： 3d kinematic analyses Amblypygi arthropod joints Autodesk Maya damon medius Heterophrynus elaphus range of motion analyses

SINGLE SERVER QUEUES WITH A BATCH MARKOVIAN ARRIVAL PROCESS ANd BULK RENEWAL OR NON-RENEWAL SERVICE

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Journal of Systems Science and Systems Engineering 2015年第3期24卷 337-363页

作者： A.d.Banik School of Basic Sciences Indian Institute of Technology

We first consider an infinite-buffer single server queue where arrivals occur according to a batch Markovian arrival process （BMAP）. The server serves customers in batches of maximum size ＇b＇ with a minimum threshold size ＇a＇. The service time of each batch follows general distribution independent of each other as well as the arrival process. The proposed analysis is based on the use of matrix-analytic procedure to obtain queue-length distribution at a post-departure epoch. Next we obtain queue-length distributions at various other epochs such as, pre-arrival, arbitrary and pre-service using relations with post-departure epoch. Later we also obtain the system-length distributions at post-departure and arbitrary epochs using queue-length distribution at post-departure epoch. Some important performance measures, like mean queue-lengths and mean waiting times have been obtained Total expected cost function per trait time is also derived to determine the locally optimal values of a and b. Secondly, we perform similar analysis for the corresponding infinite-buffer single server queue where arrivals occur according to a BMAP and service process in this case follows a non-renewal one, namely, Markovian service process （MSP）.

关键词： Bulk service (a b)-rule system-length distribution infinite-buffer queue batch Markovian arrival process Markovian service process matrix-analytic procedure cost control cloud computing

Standardization in optical coating characterisation

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光学精密工程 2005年第4期13卷 435-453页

作者： d. Ristau Laser Zentrum Hannover 30419 Hannover Germany

In the rapid development course of laser technology and modern optics, optical metrology continuously gains importance for the quality management in the industrial production environment and also for research in optical coatings. Besides absorption and scatter losses, the spectral characteristics and laser induced damage thresholds are considered as common quality factors for coated optical components and often define the optimization targets for new products and applications. Also, these quality parameters are the basis for the comparison of commercial optics and can be found in the product catalogues of most manufacturers of optical components. As a consequence, standardization of characterisation procedures for these fundamental properties evolved to a crucial point for the optics industry. during the last decade, adapted standard measurement techniques have been elaborated and discussed by representatives from many industrial companies and research institutes within working groups of the International Organisation for Standardization (ISO). In this contribution, the current state of standardized characterisation techniques for optical coatings is summarised. Selected standards for the measurement of absorption (ISO 11551), scattering (ISO 13696) and laser induced damage thresholds (ISO 11254, Parts 1 and 2) will be described and discussed in view of their applicability and reproducibility. The report will be concluded by an outlook on the current projects and future tasks of standardization in optics characterisation.

关键词：光学涂覆技术激光技术光谱标准化激光仪器

Structural and mass transport properties of liquid ytterbium in the temperature range 1123 K–1473 K

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Chinese Physics B 2023年第6期32卷 481-488页

作者： d d Satikunvar N K Bhatt B Y Thakore department of Physics Sardar Patel UniversityVallabh VidyanagarGujarat 388120India department of Physics Maharaja Krishnakumarsinhji Bhavnagar UniversityBhavnagarGujarat 364001India

We have studied the structural and atomic transport properties of liquid f-shell Yb in the temperature range 1123 K–1473 K. Pair interactions between atoms are derived using a local pseudopotential. The potential parameters are fitted to the phonon dispersion curve at room temperature. The local pseudopotential used in the present study is computationally more efficient with only three parameters, and it is found to be transferable to the liquid phase without changing the *** the various computed properties agree with reported theoretical and experimental findings, the adopted fitting scheme is justified. As a significant outcome of the study, we find that(i) the melting in Yb is governed by the Lindemann's law,(ii)the mass transport mechanism obeys the Arrhenius law,(iii) the role of the three-particle correlation function in deriving the velocity autocorrelation function is small,(iv) the mean-square atomic displacement is more sensitive to the choice of interaction potential than the other bulk properties, and(v) liquid Yb does not show liquid–liquid phase transition within the studied temperature range. Further, due to the good description of the structural and mass transport properties, we propose that Yb remains divalent at reduced density.

关键词： transport properties pseudopotential single-particle dynamics ytterbium