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61.
The Absolute Nodal Coordinate Formulation (ANCF) has been initiated in 1996 by Shabana (Computational Continuum Mechanics,
3rd edn., Cambridge: Cambridge University Press, 2008). It introduces large displacements of planar and spatial finite elements relative to the global reference frame without
using any local frame. A sub-family of beam, plate and cable finite elements with large deformations are proposed and employed
the 3D theory of continuum mechanics. In the ANCF, the nodal coordinates consist of absolute position coordinates and gradients
that can be used to define a unique rotation and deformation fields within the element. In contrast to other large deformation
formulations, the equations of motion contain constant mass matrices as well as zero centrifugal and Coriolis inertia forces.
The only nonlinear term is a vector of elastic forces. This investigation concerns a way to generate new finite element in
the ANCF for laminated composite plates. This formulation utilizes the assumption that the bonds between the laminae are thin
and shear is non-deformable. Consequently, the Equivalent Single Layer, ESL model, is implemented. In the ESL models, the
laminate is assumed to deform as a single layer, assuming a smooth variation of the displacement field across the thickness.
In this paper, the coupled electromechanical effect of Piezoelectric Laminated Plate is imposed within the ANCF thin plate
element, in such a way as to achieve the continuity of the gradients at the nodal points, and obtain a formulation that automatically
satisfies the principle of work and energy. Convergence and accuracy of the finite-element ANCF Piezoelectric Laminated Plate
is demonstrated in geometrically nonlinear static and dynamic test problems, as well as in linear analysis of natural frequencies.
The computer implementation and several numerical examples are presented in order to demonstrate the use of the formulation
developed in this paper. A comparison with the commercial finite element package COMSOL MULTIPHYSICS () is carried out with an excellent agreement. 相似文献
62.
We compute the \(L^2\)-norm of any minimizer of the Ginzburg–Landau functional in a planar domain with a finite number of corners. Our computations are valid for a uniform applied magnetic field, large Ginzburg–Landau parameter and in the regime where superconductivity is confined near the corners of the domain. 相似文献
63.
High‐energy‐resolution diced spherical quartz analyzers for resonant inelastic X‐ray scattering 下载免费PDF全文
Ayman H. Said Thomas Gog Michael Wieczorek XianRong Huang Diego Casa Elina Kasman Ralu Divan Jung Ho Kim 《Journal of synchrotron radiation》2018,25(2):373-377
A novel diced spherical quartz analyzer for use in resonant inelastic X‐ray scattering (RIXS) is introduced, achieving an unprecedented energy resolution of 10.53 meV at the Ir L3 absorption edge (11.215 keV). In this work the fabrication process and the characterization of the analyzer are presented, and an example of a RIXS spectrum of magnetic excitations in a Sr3Ir2O7 sample is shown. 相似文献
64.
Ayman Nafady Ylias Mohammad Sabri Ahmad Esmaielzadeh Kandjani Ali M. Alsalme Alan M. Bond Suresh Bhargava 《Journal of Solid State Electrochemistry》2016,20(12):3303-3314
Facile synthesis and characterization of the highly conducting, thermodynamically favored, Tl(TCNQ) phase II microrods/nanorods onto conducting (glassy carbon (GC)) and semiconducting (indium tin oxide (ITO)) surfaces have been accomplished via redox-based transformation of 7,7,8,8-tetracynoquinodimethane (TCNQ) microcrystals. This electrochemically irreversible process involves the one-electron reduction of surface-confined solid TCNQ into TCNQ·? with concomitant incorporation of the Tl+ (aq) cation, from the bulk solution, at the triple-phase boundary, GC or ITO│(TCNQ(s)/TCNQ·? (s))│Tl+ (aq), through a nucleation/growth mechanism. Consistent with the conceptually related M(TCNQ) systems (M+ = Li+, Na+, K+, Ag+, and Cu+), the TCNQ/Tl(TCNQ) interconversion is strongly dependent upon scan rate, Tl+ (aq) electrolyte concentration, and the method of attaching solid TCNQ onto the electrode surface. Spectroscopic (infrared (IR) and Raman), microscopic (scanning electron microscopy (SEM)), and surface science (X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD)) characterization of the electrochemically synthesized material revealed formation of pure Tl(TCNQ) phase II. Importantly, the generic solid-state electrochemical approach used in this study not only offers facile protocol for controllable and preferential synthesis of Tl(TCNQ) phase II but also provides access to fabricate and tune the morphology to yield microrod/nanorod networks. 相似文献
65.
The main aim of this research is to investigate the effect of salt concentration on the dielectric properties(AC (σAC),permittivity(ε′),dielectric loss(ε″),and dielectric relaxation process) and melting behavior of polyethylene oxide (PEO)/CdCl2 complexes.The dielectric study was carried out over a frequency range 10-335 kHz and a temperature range 25-45℃.The AC conductivity,permittivity and dielectric loss of the PEO/CdCl2 complexes increase with increasing salt concentration and temperature.Also,it was found that the addition of CdCl2 salt to PEO host reduced the melting temperature of PEO host.Dielectric results reveal that the relaxation process of these complexes is due to viscoelastic relaxation or non-Debye relaxation at room temperature.Additionally,it was found that relaxation behavior remained viscoelastic at different temperatures and salt concentrations. 相似文献
66.
The development of robust infrared fibers is crucial for harnessing the capabilities of new mid-infrared lasers. We present a novel approach to the fabrication of chalcogenide glass fiber preforms: one-step multimaterial extrusion. The preform consists of a glass core and cladding surrounded by a built-in, thermally compatible, polymer jacket for mechanical support. Using this approach we extrude several preform structures and draw them into robust composite fibers. Furthermore, the polymer cladding allows us to produce robust tapers with submicrometer core diameter. 相似文献
67.
68.
Essential oil from wild growing Artemisia vulgaris L. originating in Erie, Pennsylvania was obtained by hydrodistillation of the aerial parts of the plant. Gas chromatographic-mass spectral analysis was used to identify the major volatiles present. Up to 22 components were detected in the essential oils. Germacrene D (25%), Caryophyllene (20%), alpha-Zingiberene (15%) and Borneol (11%) represent the major components of leaf oil, while the buds were rich in 1,8-Cineole (32%), Camphor (16%), Borneol (9%), and Caryophyllene (5%). trans-2-Hexenal was also detected in the aerial parts of the plant. alpha-Zingiberene and trans-2-Hexenal have not been previously reported for Artemisia vulgaris L. The major analytes are compared to those from Artemisia vulgaris L, originating outside of the United States. 相似文献
69.
Isothiazolopyridines, pyridothiazines and pyridothiazepines are important compounds that possess valuable biological activities. This paper reports on the synthesis of these compounds using both conventional chemical methods and modern microwave techniques. 3-Bromo-6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-carboxamide, 5-arylazo-6-hydroxy-4-methyl-2-thioxo-1,2-dihydropyridine-3-carboxamides, 3,5-bis-arylazo-6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-caboxamide, 4-methyl-2,3,6,7-tetra-hydroisothiazolo[5,4-b]-pyridine-3,6-dione, 2,2'-(methylene-bis-(sulfanediyl))bis(4-methyl-6-oxo-1,6-dihydropyridine-3-carboxamide), 2-hydroxy-5-methyl-4H-pyrido[3,2-e][1,3]-thiazine-4,7(8H)-dione and 2-arylmethylene-8-hydroxy-6-methyl-2,3,4,5-tetrahydropyrido-[3,2-f][1,4]thiazepine-3,5-diones have been prepared from 6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-carboxamide. Some of these compounds were prepared using microwave-assisted reaction conditions, that provided higher yields in shorter times than the conventional methods. 相似文献
70.
This paper presents nonlinear dynamic modeling and control of flexible-link manipulators subjected to parametric excitation. The equations of motion are obtained using the Lagrangian-assumed modes method. Singular perturbation methodology is developed for the nonlinear time varying equations of motion to obtain a reduced-order set of equations. Control strategies, computed torque control and a composite control, based on the singular perturbation formulation developed, are utilized to reduce mechanical vibrations of the flexible-link and enable better tip positioning. Under the composite control technique, the effect of the value of perturbation parameter on the control signal is investigated. Numerical simulations supported by real-time experiments show that the singular-perturbation control methodology developed for the nonlinear time-varying system offers better system response over the computed torque control as the manipulator is commanded to follow a certain trajectory. 相似文献