• Geomechanics and Engineering
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• v.17 no.3
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• pp.247-252
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• 2019

Modulus of deformation of soil is an essential parameter used for design analysis of foundations, despite its importance; little attention is paid to developing empirical models for predicting the sensitivity of deformation moduli to other parameters that obtained from the pressuremeter tests. Various methods of analysis used to predict the horizontal at rest pressure from pressuremeter testing ($P_o$), these values showed distinctive variations, five methods used to evaluate the values of horizontal at rest pressure, these values been used to evaluate the modulus of elasticity using three methods of analysis. The values of modulus showed distinctive increase when the values of horizontal at rest pressure increase for the same pressuremeter test, these increases may reach to 65%. This sensitivity of the moduli to values of horizontal lead the author to propose some reliable methods of analysis for both the horizontal at rest pressure and the modulus of deformation from pressuremeter testing.

• Steel and Composite Structures
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• v.43 no.2
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• pp.185-200
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• 2022

A Closed-form solution for dynamic response of a functionally graded (FG) nonlocal nanobeam due to action of moving harmonic load is presented in this paper. Due to analyzing in small scale, a nonlocal elasticity theory is utilized. The governing equation and boundary conditions are derived based on the Euler-Bernoulli beam theory and Hamilton's principle. The material properties vary through the thickness direction. The harmonic moving load is modeled by Delta function and the FG nanobeam is simply supported. Using the Laplace transform the dynamic response is obtained. The effect of important parameters such as excitation frequency, the velocity of the moving load, the power index law of FG material and the nonlocal parameter is analyzed. To validate, the results were compared with previous literature, which showed an excellent agreement.

• Advances in nano research
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• v.13 no.2
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• pp.147-164
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• 2022

This article investigates the longitudinal vibration of a nanorod embedded in viscoelastic medium according to the nonlocal strain gradient theory. Viscoelastic medium is considered based on Kelvin-Voigt model. Governing partial differential equation is derived based on longitudinal equilibrium and analytical solution is obtained by adopting harmonic motion solution for the nanorod. Modal frequencies and corresponding damping ratios are presented to demonstrate the influences of nonlocal parameter, material length scale, elastic and damping parameters of the viscoelastic medium. It is observed that material length scale parameter is very influential on modal frequencies especially at lower values of nonlocal parameter whereas increase in length scale parameter has less effect at higher values of nonlocal parameter when the medium is purely elastic. Elastic stiffness and damping coefficient of the medium have considerable impacts on modal frequencies and damping ratios, and the highest impact of these parameters on frequency and damping ratio is seen in the first mode. Results calculated based on strain gradient theory are quite different from those calculated based on classical elasticity theory. Hence, nonlocal strain gradient theory including length scale parameter can be used to get more accurate estimations of frequency response of nanorods embedded in viscoelastic medium.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.167-168
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• 2020

본 연구는 학업중단청소년 패널조사 5차년도 조사(2017년) 데이터를 활용하여 학업중단 청소년의 진로불안이 우울에 영향을 미치는 과정에서 외적 보호요인으로 작용하는 사회적 관계(부모애착, 또래애착)와 내적 보호요인으로 작용하는 자아탄력성의 매개효과를 검증하고자 한다.

• Advances in aircraft and spacecraft science
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• v.10 no.1
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• pp.51-65
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• 2023

In this paper, the effect of deepness on in-plane free vibration behavior of a curved functionally graded (FG) nanobeam based on nonlocal elasticity theory has been investigated. Differential equations and boundary conditions have been developed based on Hamilton's principle. In order to figure out the size effect, nonlocal theory has been adopted. Properties of material vary in radial direction. By using Navier solution technique, the amount of natural frequencies has been obtained. Also, to take into account the deepness effect on vibrations, thickness to radius ratio has been considered. Differences percentage between results of cases in which deepness effect is included and excluded are obtained and influences of power-law exponent, nonlocal parameter and arc angle on these differences percentage are studied. Results show that arc angle and power law exponent parameters have the most influences on the amount of the differences percentage due to deepness effect. It has been observed that the inclusion of geometrical deep term and material distribution results in an increase in sensitivity of dimensionless natural frequency about variation of aforementioned parameters and a change in variation range of natural frequency. Finally, several numerical results of deep and shallow curved functionally graded nanobeams with different geometry dimensions are presented, which may serve as benchmark solutions for the future research in this field.

• Journal of Sericultural and Entomological Science
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• v.51 no.1
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• pp.41-47
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• 2013

In this study, silkgland powder of silkworm were investigated to see possibility for cosmetic powder materials. To test possibility as a baby powder cosmetics, total content rate of amino acids, DPPH free radical scavenging assay, MTT assay, and clinical trial were done. According to the result of the analysis of the amino acids of silkgland powder, serin (26.77%) content was the highest and asparatic acid (15.47%), and glycine (9.62%) were followed. DPPH free radical scavenging activity of silkgland powder was lower than vitamin C by 82.3% and 97%, respectively, which is relatively good. And the moisture and elasticity effect were increased in silkgland powder compared to control cosmetics by 210% and 185%, relatively. Thus, these results suggest that silkgland powder of silkworm may have beneficial properties as a material for cosmeceuticals.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.3
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• pp.115-125
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• 2014

This paper has two purposes. The first is to suggest the new and simple method to derive a regional input-output model from the national input-output table published by the Bank of Korea. The interregional input-output table has not been devised in spite of its potential use while the national table has been made every five years with the revised version during each five years. Second, this paper aims to derive Kangwon interregional input-output model from the national model using the regional supply proportion of industry and to analyze the effect of medical tourism industry on the regional economy of Kangwon Province. The paper measures, in particular, the effect of medical tourism industry on the financial self-sufficiency of Kangwon Province using the estimated output elasticity of tax revenue with the autoregressive distributed lag scheme ADL(1,1) in which the dependent variable and the single explanatory variable are each lagged once.

• Korean Journal of Human Ecology
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• v.14 no.1
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• pp.133-141
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• 2005

This research was designed to investigate the effect of a hand and a sensibility image on the preference to skirt textiles. 131 male and female college students were surveyed and 10 kinds of preferred fabrics were used each as a specimen for all 4 seasons. Factor analysis, t-test, Pearson's correlation, and regression were used for a statistical analysis by SPSS WIN 10.0. The results of this study are as follows: 1. In spring/fall season, 6 factors including 'elasticity/flexibility' were extracted as a hand factor, and 2 factors including 'modern elegance' were extracted as a sensibility factor in skirt textiles. 2. In summer season, 5 factors such as 'unevenness/stiffness' were extracted as a hand factor and 2 factors such as 'modern elegance romantic' as a sensibility image. 3. In winter season, 7 factors including 'elasticity' were extracted as a hand factor and 2 factors including 'modern elegance romantic' as a sensibility image. 4. Significant correlations existed between a hand and a sensibility image in spring/fall, summer, and winter. 5. A sensibility image was one of the important factors in the preference to skirt textiles in spring/fall, summer, and winter.

• Wind and Structures
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• v.26 no.4
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• pp.205-214
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• 2018

In this paper, the thermo-mechanical buckling characteristics of functionally graded (FG) size-dependent Timoshenko nanobeams subjected to an in-plane thermal loading are investigated by presenting a Navier type solution for the first time. Material properties of FG nanobeam are supposed to vary continuously along the thickness according to the power-law form and the material properties are assumed to be temperature-dependent. The small scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. The nonlocal governing equations are derived based on Timoshenko beam theory through Hamilton's principle and they are solved applying analytical solution. According to the numerical results, it is revealed that the proposed modeling can provide accurate critical buckling temperature results of the FG nanobeams as compared to some cases in the literature. The detailed mathematical derivations are presented and numerical investigations are performed while the emphasis is placed on investigating the effect of the several parameters such as material distribution profile, small scale effects and aspect ratio on the critical buckling temperature of the FG nanobeams in detail. It is explicitly shown that the thermal buckling of a FG nanobeams is significantly influenced by these effects. Numerical results are presented to serve as benchmarks for future analyses of FG nanobeams.

• Structural Engineering and Mechanics
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• v.62 no.6
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• pp.695-702
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• 2017

In this work, a nonlocal zeroth-order shear deformation theory is developed for the nonlinear postbuckling behavior of nanoscale beams. The beauty of this formulation is that, in addition to including the nonlocal effect according to the nonlocal elasticity theory of Eringen, the shear deformation effect is considered in the axial displacement within the use of shear forces instead of rotational displacement like in existing shear deformation theories. The principle of virtual work together of the nonlocal differential constitutive relations of Eringen, are considered to obtain the equations of equilibrium. Closed-form solutions for the critical buckling load and the amplitude of the static nonlinear response in the postbuckling state for simply supported and clamped clamped nanoscale beams are determined.