• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.3
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• pp.73-83
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• 1982

study aims to derive a rational method for the analysis of the farm silo supported on an elastic foundation in which it is assumed that the reaction pressure of the soil at a point is proportional to the deflection at that point. In order to investigate the effects of an elastic foundation on the behaviour of the structures on it, the analysis of the farm silo resting on an elastic foundation was compared with the solution that the ground support may be assumed uniform (which was obtained from part I of this paper). To calculate the deformation of an elastic foundation, Boussinesq's solution which allows an interaction of the various parts of ground was adopted. In this case, the foundation was treated as a superparametric element additionally. In the evaluation of an element stiffness matrix, Gauss quadrature' was used. In above numerical integration, 3-point rule for the farm silo wall and the footing was introduced and 2-point rule for the evaluation of a reaction between the footing and the elastic foundation was adopted. The stresses of a farm silo on an elastic foundation were smaller than those which the distribution of contact pressure between the footing and the soil is assumed uniformly. Since the differences of stresses were remarkable in PS structures than RC structures, it is desirable that designers take into account the effect of an elastic foundation for the case of PS structures. It can be noted that while the effect of an elastic foundation was more conspicuously observed in near of the ground, the value of stresses at far from the soil was little affected by an supported soil.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2171-2175
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• 2013

The electronic structure and elastic properties of the 4d transition metal carbides MC (M = Y, Zr, Nb, Rh) were studied by means of extended H$\ddot{u}$ckel tight-binding band electronic structure calculations. As the valence electron population of M increases, the bulk modulus of the MC compounds in the rocksalt structure does not increase monotonically. The dominant covalent bonding in these compounds is found to be M-C bonding, which mainly arises from the interaction between M 4d and C 2p orbitals. The bonding characteristics between M and C atoms affecting the variation of the bulk modulus can be understood on the basis of their electronic structure. The increasing bulk modulus from YC to NbC is associated with stronger interactions between M 4d and C 2p orbitals and the successive filling of M 4d-C 2p bonding states. The decreased bulk modulus for RhC is related to the partial occupation of Rh-C antibonding states.

• Structural Engineering and Mechanics
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• v.67 no.5
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• pp.517-525
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• 2018

In this study, we investigate the vibration of single-walled carbon nanotubes embedded in a polymeric matrix using nonlocal elasticity theories with account arbitrary boundary conditions effects. A Winkler type elastic foundation is employed to model the interaction of nanobeam and the surrounding elastic medium. Influence of all parameters such as nonlocal small-scale effects, Winkler modulus parameter, vibration mode and aspect ratio of nanobeam on the vibration frequency are analyzed and discussed. The mechanical properties of carbon nanotubes and polymer matrix are treated and an analytical solution is derived using the governing equations of the nonlocal Euler-Bernoulli beam models. Solutions have been compared with those obtained in the literature and The results obtained show that the non-dimensional natural frequency is significantly affected by the small-scale coefficient, the vibrational mode number and the elastic medium.

• Electrical & Electronic Materials
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• v.7 no.6
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• pp.473-480
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• 1994

The electron tunnel effect in polvimide LB films sandwiched between metal electrodes has been investigated in the present work by a study of both the elastic and inelastic tunneling components. By the results of elastic tunneling experiments in Au/Pl/Au tunneling junction, we can judge the height and thickness of tunnel barrier. The inelastic current in Inelastic Electron Tunneling Spectroscopy(IETS) is due to the interaction of the tunneling electron with the vibrational modes of the molecular species in the barrier. Measurements are done on Au/PI/Pb tunneling junctions. The spectra obtained are the second derivatives of the current-voltage characteristics of these junctions : specifically, d$^{2}$1/dV$^{2}$ as a function of voltage V. Because the energies measured by IETS can be directly compared to those measured by infrared and Raman spectroscopy, IR-RAS spectroscopy also measured for reference.

• Interaction and multiscale mechanics
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• v.4 no.2
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• pp.123-137
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• 2011

We review a series of crack problems arising in the general deformations of a linearly elastic solid (Mode-I, Mode-II and Mode-III crack) and, perhaps more significantly, when the contribution of surface effects are taken into account. The surface mechanics are incorporated using the continuum based surface/interface model of Gurtin and Murdoch. We show that the deformations of an elastic solid containing a single crack can be decoupled into in-plane (Mode-I and Mode-II crack) and anti-plane (Mode-III crack) parts, even when the surface mechanics is introduced. In particular, it is shown that, in contrast to classical fracture mechanics (where surface effects are neglected), the incorporation of surface elasticity leads to the more accurate description of a finite stress at the crack tip. In addition, the corresponding stress fields exhibit strong dependency on the size of crack.

• Advances in aircraft and spacecraft science
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• v.7 no.1
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• pp.41-52
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• 2020

The effect of relaxation times is studied on plane waves propagating through semiconductor half-space medium by using the eigen value approach. The bounding surface of the half-space is subjected to a heat flux with an exponentially decaying pulse and taken to be traction free. Solution of the field variables are obtained in the form of series for a general semiconductor medium. For numerical values, Silicon is considered as a semiconducting material. The results are represented graphically to assess the influences of the thermal relaxations times on the plasma, thermal, and elastic waves.

• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.28-34
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• 1999

The effects of the viscosity of an adjacent viscous fluid on the characteristics of the elastic waves have been studied theoretically and experimentally. Expressions for the wave speed and attenuation of the elastic waves of transverse motion, such as the torsional wave propagating in a circular cylinder and the Love wave in a layered half-space solid, have been obtained as functions of the viscosity and mass density of the fluid by exact and asymptotic analyses. The theoretical results have been compared with experimental observations, and it has been demonstrated that a device described herein can be used as a sensor for measuring the viscosity of a fluid with a known mass density.

• Elastomers and Composites
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• v.34 no.3
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• pp.262-268
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• 1999

Effect of carbon blacks (CBs) on the stress relaxation and the elastic recovery of uncrosslinked natural rubber (NR) was examined. It was found that if the type of CB is characterized by smaller size and higher structure, the stress relaxation is more delayed and the elastic recovery becomes more active. These results are attributed to the degree of bound rubber, i.e., the interaction between NR and CB.

• Structural Engineering and Mechanics
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• v.9 no.2
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• pp.127-139
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• 2000

The isoparametric element method is used for a plate on non-homogenous foundation. The surface displacement due to a point force acting on the non-homogeneous foundation is the fundamental solution. Based on this analysis, the interaction between the foundation and plate can be determined and the reaction of the foundation can be treated as the external force to the plate. Therefore, only the plate needs to be divided into some elements. The method presented in this paper can be used in cases such as thin or thick plate, different plate shapes, various loading, homogenous and non-homogenous foundations. The examples in this paper show that this method is versatile, efficient and highly accurate.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.2
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• pp.133-140
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• 2005

A Plate on the elastic half-space may be generally be analyzed by the finite element method. However, there ate some difficulties to obtain the flexibility matrix of the foundation based on the Boussinesq's theory. In this study, an efficient numerical procedure which uses the analysis results of the vertical displacements due to the uniformly distributed loading in a circular area is presented. Some numerical examples represent better results than those of numerical integration technique or subsection method especially in the case of irregular mesh pattern.