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surface effect and non-local elasticity in wave propagation of functionally graded piezoelectric nano-rod excited to applied voltage

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Applied mathematics and mechanics(English Edition) 2016年第3期37卷 289-302页

作者： m.AREFI Department of solid mechanics Faculty of Mechanical EngineeringUniversity of Kashan

A non-local solution for a functionally graded piezoelectric nano-rod is pre- sented by accounting the surface effect. This solution is used to evaluate the charac- teristics of the wave propagation in the rod structure. The model is loaded under a two-dimensional （2D） electric potential and an initially applied voltage at the top of the rod. The mechanical and electrical properties are assumed to be variable along the thick- ness direction of the rod according to the power law. The Hamilton principle is used to derive the governing differential equations of the electromechanical system. The effects of some important parameters such as the applied voltage and gradation of the material properties on the wave characteristics of the rod are studied.

关键词： wave propagation non-local elasticity surface effect Love rod model non-homogeneous index voltage

multi-channel retarding field analyzer for EAsT

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Plasma science and Technology 2018年第5期20卷 1-5页

作者： m HENKEL D HOsCHEN Y LIANG Y LI s C LIU D NICOLAI N sANDRI G sATHEEsWARAN N YAN H X ZHANG the EAsT team Forschungszentrum Jülich GmbH Institut für Energie-und Klimaforschung–PlasmaphysikPartner of the Trilateral Euregio Cluster(TEC)D-52425 JulichGermany Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China

A multi-channel retarding field analyzer（mC-RFA） including two RFA modules and two Langmuir probes to measure the ion and electron temperature profiles within the scrape-off layer was developed for investigations of the interplay between magnetic topology and plasma transport at the plasma *** mC-RFA probe for the stellarator W7-X and first measurements at the tokamak EAsT was *** probe head allows simultaneous multichannel ion temperature as well as for electron temperature *** usability for radial correlation measurements of the measured ion currents is also given.

关键词： retarding field analyzer multi-channel EAsT ion temperature diagnostic

Nonlinear optimal control of rotating flexible shaft in active magnetic bearings

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science China(Technological sciences) 2011年第5期54卷 1084-1094页

作者： G. s. TOmBUL s. P. BANKs Department of Automatic Control & systems Engineering The University of Sheffield

The optimal control of nonlinear systems has been studied for years by many researchers. However, the application of optimal control problem to nonlinear non-affine systems needs more attention. In this paper we propose an optimal control design technique for a class of nonlinear and control non-affine equations. The dynamic equations of a flexible shaft supported by a pair of active magnetic bearings (AmBs) are used as the nonlinear control non-affine equations. mathematical model for the flexible beam is chosen to be the well known Timoshenko beam model, which takes rotary inertia and shear deformations into account, and it is assumed that the shaft is supported by two frictionless bearings at the ends. The effective control of such systems is extremely important for very high angular velocity shafts which are a feature of many modern machines. The control must be able to cope with unbalanced masses and hence be very robust. We shall approach the problem by discretising the Timoshenko beam model and using standard difference formulae to develop a finite-dimensional model of the system. Then we use a recently developed technique for controlling nonlinear systems by reducing the problem to a sequence of linear time-varying (LTV) systems. An optimal control designed for each approximating linear, time-varying system and recent results show that this method will converge uniformly on compact time intervals to the optimal solution.

关键词： approximation technique nonlinear optimal control timoshenko beam active magnetic bearings

Polar Duals of Rotors

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Acta mathematica sinica,English series 1996年第1期12卷 40-42页

作者： Ghandehari m. Department of mathematics Noval Postgraduate school monterey, CA 93943 U. s. A. Department of mathematics Noval Postgraduate School Monterey USA

Assume K is a rotor in a regular simplex of heihgt 1 in an n-dimensional Euclidean space. Let K~* denote the polar dual of K. Then the volume V(K~*) satisfies the inequality V(K~*)≥(n+1)~nω_n, where ω_n denotes the volume of an n-dimensional unit ball. Equality holds if and only if K is a ball centered at the centroid of the simplex.

关键词： Rotor Polar dual Regulor simplex

space-Resolved VUV and EUV spectrometers in HL-2A

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Plasma science and Technology 2013年第2期15卷 110-114页

作者：崔正英周航宇 s.mORITA 傅炳忠孙平高亚东 m.GOTO 徐媛董春凤杨青巍 southwestern Institute of Physics Chengdu 610041 China National Institute for Fusion science Toki 509-5292 Gifu Japan

A normal incidence vacuum ultraviolet （VUV） and a grazing incidence extreme ultraviolet （EUV） spectrometers have been developed for the edge and core impurity measure- ments in HL-2A tokamak. The VUV and the EUV spectrometers cover wavelength ranges of 300-3200 A and 50-500A, respectively. A spatial resolution of 2 mm has been achieved for the VUV spectrometer when a space-resolved slit 50 #m in width is used. The space-resolved slit is placed between the entrance slit and the grating of the spectrometer. The spectral resolutions of 0.15/~ for the VUV spectrometer in the wavelength coverage of the concave 1200 grooves/mm grating and of 0.22A for the EUV spectrometer at λ=200A with a flat-field laminar-type holo- graphic grating are obtained. The sensitivity of the VUV spectrometer was calibrated in situ with the plasma bremsstrahlung radiation. The experimental results from both spectrometers are presented, especially the line intensity radial profiles measured by the VUV spectrometer.

关键词： VUV spectra EUV spectra spectrometer spatial resolution

Effect of heat treatment on corrosion properties of CuAlNi shape memory alloy

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Transactions of Nonferrous metals society of China 2018年第6期28卷 1149-1156页

作者： L.VRsALOVIC I.IVANIC s.KOZUH s.GUDIC B.KOsEC m.GOJIC Department of Electrochemistry and materials Protection Faculty of Chemistry and Technology University of Split Rudera Bogkovica 35 21000 Split Croatia Faculty of metallurgy University of Zagreb Aleja narodnih heroja 3 44103 Sisak Croatia Faculty of Natural sciences and Engineering University of Ljubljana Askerceva cesta 12 1000 Ljubljana Slovenia

The effect of heat treatment on corrosion properties of CuAlNi shape memory alloy was investigated in 0.9% Na Cl solution at p H 7.4 and 37 ℃ by open circuit potential measurements, polarisation techniques, and electrochemical impedance spectroscopy. Investigations were performed on CuAlNi alloy samples in as-cast state and after heat treatment procedure containing annealing at 850, 885 and 920 ℃ followed by water quenching. Electrochemical impedance measurement results indicate that heat treatment of CuAlNi alloy leads to the increase in charge transfer resistance and surface layer resistance and the decrease in values of capacitance of the double and surface layers, indicating higher corrosion resistance compared with the as-cast CuAlNi alloy. The increase in polarisation resistance and the decrease in corrosion current density of heat-treated CuAlNi alloy also suggest beneficial influence of heat treatment on corrosion resistance of CuAlNi alloy. Optical microscopy, sEm/EDX and XRD analysis of samples surface after polarisation measurements show the occurrence of pitting corrosion on the electrode surfaces, with the existence of CuCl2, AlCl3 and Cu2Cl（OH）3 compounds as the surface corrosion products.

关键词： CuAlNi alloy corrosion polarcisation electrochemical methods sEm

Effect of slip velocity on Casson thin film flow and heat transfer due to unsteady stretching sheet in presence of variable heat flux and viscous dissipation

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Applied mathematics and mechanics(English Edition) 2015年第10期36卷 1273-1284页

作者： A.m.mEGAHED Department of mathematics Faculty of Science Benha University

The aim of the present paper is to study flow and heat transfer charac- teristics of a viscous Casson thin film flow over an unsteady stretching sheet subject to variable heat flux in the presence of slip velocity condition and viscous dissipation. The governing equations are partial differential equations. They are reduced to a set of highly nonlinear ordinary differential equations by suitable similarity transformations. The re- sulting similarity equations are solved numerically with a shooting method. Comparisons with previous works are macle, and the results are found to be in excellent agreement. In the present work, the effects of the unsteadiness parameter, the Casson parameter, the Eckert number, the slip velocity parameter, and the Prandtl number on flow and heat transfer characteristics are discussed. Also, the local skin-friction coefficient and the local Nusselt number at the stretching sheet are computed and discussed.

关键词： Casson thin film unsteady stretching sheet numerical solution slip effect,viscous dissipation variable heat flux

A Probabilistic Trust model and Control Algorithm to Protect 6G Networks against malicious Data Injection Attacks in Edge Computing Environments

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Computer modeling in Engineering & sciences 2024年第10期141卷 631-654页

作者： Borja Bordel sánchez Ramón Alcarria Tomás Robles Department of Computer systems Universidad Politécnica de MadridMadrid28031Spain Department of Geospatial Engineering Universidad Politécnica de MadridMadrid28031Spain

Future 6G communications are envisioned to enable a large catalogue of pioneering *** will range from networked Cyber-Physical systems to edge computing devices,establishing real-time feedback control loops critical for managing Industry 5.0 deployments,digital agriculture systems,and essential *** provision of extensive machine-type communications through 6G will render many of these innovative systems autonomous and *** full automation will enhance industrial efficiency significantly,it concurrently introduces new cyber risks and *** particular,unattended systems are highly susceptible to trust issues:malicious nodes and false information can be easily introduced into control ***,Denialof-service attacks can be executed by inundating the network with valueless *** anomaly detection schemes require the entire transformation of the control software to integrate new steps and can only mitigate anomalies that conform to predefined mathematical *** based on an exhaustive data collection to detect anomalies are precise but extremely *** models,with their limited understanding of mobile networks,can achieve precision rates no higher than 75%.Therefore,more general and transversal protection mechanisms are needed to detect malicious behaviors *** paper introduces a probabilistic trust model and control algorithm designed to address this *** model determines the probability of any node to be *** channels are pruned for those nodes whose probability is below a given *** trust control algorithmcomprises three primary phases,which feed themodel with three different probabilities,which are weighted and ***,anomalous nodes are identified using Gaussian mixture models and clustering ***,traffic patterns are studied using digital Bessel functions and the functional scalar ***,the in

关键词： 6G networks noise injection attacks Gaussian mixture model Bessel function traffic filter Volterra filter

Pulsed-Laser Annealing of NiTi shape memory Alloy Thin Film

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Journal of materials science & Technology 2009年第1期25卷 135-140页

作者： s.K. sadrnezhaad E. Rezvani s. sanjabi A.A. Ziaei moayed materials and Energy Research Center P.O. Box 14155-4777 Tehran Iran Department of materials science and Engineering Sharif University of Technology P.O. Box 1156-9466 Tehran Iran Department of materials science and Engineering Tarbiat Modarres University P.O. Box 14115-143 Tehran Iran

Local annealing of amorphous NiTi thin films was performed by using an Nd：YAG 1064 nm wavelength pulsed laser beam. Raw samples produced by simultaneous sputter deposition from elemental Ni and Ti targets onto unheated si （100） and silica （111） substrates were used for annealing. Delicate treatment with 15.92 W/mm^2 power density resulted in crystallization of small spots; while 16.52 and 17.51 W/mm^2 power densities caused ablation of the amorphous layer. Optical microscopy, scanning electron microscopy, X-ray diffraction and atomic force microscopy were performed to characterize the microstructure and surface morphology of the amorphous/crystallized spot patterns.

关键词： Local heat treatment NiTi thin film Pulsed laser annealing Amorphous/crystallized spot composite