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991.
A substructuring technique is presented for transient dynamic analysis of systems composed of interconnected rigid and elastic bodies that undergo large angular displacements. Displacement of elastic bodies is represented by superposition of local linear elastic deformation on large displacement of body reference coordinate systems. Elastic bodies are thus represented by combined sets of reference and local elastic generalized coordinates. Modal analysis and substructuring of individual elastic components allow for elimination of insignificant modes. Equations of motion and constraint are formulated in terms of mixed sets of modal and reference generalized coordinates. Planar and spatial linkages with flexible elements are presented to illustrate use of the method developed. 相似文献
992.
Anis Hamza Fakeeha Muhammad Awais Naeem Wasim Ullah Khan Ahmed Elhag Abasaeed Ahmed Sadeq Al-Fatesh 《化学物理学报(中文版)》2014,27(2):214-220
用浸渍法制备γ-Al2O3负载的Ni-Mn双金属催化剂.在500-700。C按照17:17:2的C02/CHa/N2比例,以36mL/min的载气流速进行甲烷二氧化碳重整反应,利用甲烷二氧化碳的转化率、生成的合成气H2/CO比例以及长期稳定性等指标评价了催化剂的催化性能.实验表明,添加Mn提高催化性能并使双金属催化剂的稳定性更高,比单金属催化剂更好地抑制焦炭生成,Mn最合适的添加量为0.5wt%.通过BET、C02-TPD、TGA、XRD、SEM、EDX和FTIR各种技术对催化剂进行了表征. 相似文献
993.
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
994.
Magdy?A.?EzzatEmail author Ahmed?S.?El Karamany Mohsen?A.?Fayik 《Archive of Applied Mechanics (Ingenieur Archiv)》2012,82(4):557-572
In this work, the field equations of the linear theory of thermoelasticity have been constructed in the context of a new consideration
of Fourier law of heat conduction with time-fractional order and three-phase lag. A uniqueness and reciprocity theorems are
proved. One-dimensional application for a half-space of elastic material in the presence of heat sources has been solved using
Laplace transform and state space techniques Ezzat (Canad J Phys Rev 86:1241–1250, 2008). According to the numerical results and its graphs, conclusion about the new theory has been established. 相似文献
995.
Irfan Anjum Badruddin N. J. Salman Ahmed Abdullah A. A. A. Al-Rashed Jeevan Kanesan Sarfaraz Kamangar H. M. T. Khaleed 《Transport in Porous Media》2012,91(2):697-715
The present study is intended to study heat and mass transfer in a vertical annular cylinder embedded with saturated porous
medium. The inner surface of cylinder is maintained at uniform wall temperature and uniform wall concentration. The governing
partial differential equations are non-dimensionalised and solved by using finite element method (FEM). The porous medium
is discritised using triangular elements with uneven element size. Large number of smaller-sized elements are placed near
the walls of the annulus to capture the smallest variation in solution parameters. The results are reported for both aiding
and opposing flows. The effects of various non-dimensional numbers such as buoyancy ratio, Lewis number, Rayleigh number,
aspect ratio, etc on heat and mass transfer are discussed. The temperature and concentration profiles are presented. 相似文献
996.
997.
Mosayeb Naseri Mona Abdolmaleky Fariborz Parandin Negin Fatahi Ahmed Farouk Reza Nazari 《理论物理通讯》2018,69(2):215-226
In this paper, a new quantum images encoding scheme is proposed. The proposed scheme mainly consists of four different encoding algorithms. The idea behind of the scheme is a binary key generated randomly for each pixel of the original image. Afterwards, the employed encoding algorithm is selected corresponding to the qubit pair of the generated randomized binary key. The security analysis of the proposed scheme proved its enhancement through both randomization of the generated binary image key and altering the gray-scale value of the image pixels using the qubits of randomized binary key. The simulation of the proposed scheme assures that the final encoded image could not be recognized visually. Moreover, the histogram diagram of encoded image is flatter than the original one. The Shannon entropies of the final encoded images are significantly higher than the original one, which indicates that the attacker can not gain any information about the encoded images. 相似文献
998.
999.
Raghad Saeed Hasan Shelan Khasro Tawfeeq Nahla Qader Mohammed Ahmed Ismael Khaleel 《Chinese Journal of Physics (Taipei)》2018,56(1):385-391
True random number generators are essential components for communications to be confidentially secured. In this paper a new method is proposed to generate random sequences of numbers based on the difference of the arrival times of photons detected in a coincidence window between two single-photon counting modules. 相似文献
1000.
Koji Nagata Tadao Nakamura Han Geurdes Josep Batle Soliman Abdalla Ahmed Farouk Do Ngoc Diep 《International Journal of Theoretical Physics》2018,57(4):973-980
An interpretation of quantum mechanics is discussed. It is assumed that quantum is energy. An algorithm by means of the energy interpretation is discussed. An algorithm, based on the energy interpretation, for fast determining a homogeneous linear function f(x) := s.x = s 1 x 1 + s 2 x 2 + ? + s N x N is proposed. Here x = (x 1, … , x N ), x j ∈ R and the coefficients s = (s 1, … , s N ), s j ∈ N. Given the interpolation values \((f(1), f(2),...,f(N))=\vec {y}\), the unknown coefficients \(s = (s_{1}(\vec {y}),\dots , s_{N}(\vec {y}))\) of the linear function shall be determined, simultaneously. The speed of determining the values is shown to outperform the classical case by a factor of N. Our method is based on the generalized Bernstein-Vazirani algorithm to qudit systems. Next, by using M parallel quantum systems, M homogeneous linear functions are determined, simultaneously. The speed of obtaining the set of M homogeneous linear functions is shown to outperform the classical case by a factor of N × M. 相似文献