• 대한수학회보
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• 제20권2호
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• pp.99-103
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• 1983

Internal heat generation is one of the insidious conditions affecting the quality of an industrial product after it is cast, coated, molded, forged or laminated. Frequently, the product is pressed into service before the exothermic chemical reactions in the generic material has been completed. The heat liberated from this continuing chemical reaction or the residual deformation from the rheological activities in the materials must be adequately removed or prevented, or the product may be discolored, warped, weakened or even "ignited" spontaneously. Numerous instances of premature structural failures, product-recalls, and/or system-malfunctions have been recorded in recent history. The Coulee Dam was poured with pre-chilled concrete just to negate this freakish encore. It is well-known that concrete (a non-isotropic conducting medium), for instance, takes 28 days to develop its full strength. During this period of curing it is conceivable that the processes of internal heat generation, heat conduction and heat dissipation take place simultaneously inside the medium.he medium.

• 천문학회보
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• 제39권1호
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• pp.59.2-59.2
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• 2014

Radiative transfer models in a spherical, turbulent interstellar medium (ISM), in which the photon source is situated at the center, are calculated to investigate the correlation between the scattered light and the dust column density. The medium is modeled using fractional Brownian motion structures that are appropriate for turbulent ISM. The correlation plot between the scattered light and optical depth shows substantial scatter and deviation from simple proportionality. It was also found that the overall density contrast is smoothed out in scattered light. In other words, there is an enhancement of the dust-scattered flux in low-density regions, while the scattered flux is suppressed in high-density regions. The correlation becomes less significant as the scattering becomes closer to being isotropic and the medium becomes more turbulent. Therefore, the scattered light observed in near-infrared wavelengths would show much weaker correlation than the observations in optical and ultraviolet wavelengths. We also find that the correlation plot between scattered lights at two different wavelengths shows a tighter correlation than that of the scattered light versus the optical depth.

• 지구물리와물리탐사
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• 제18권4호
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• pp.232-240
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• 2015

자연 전자기장을 이용하여 지하 매질의 전기적 구조를 규명하는 자기지전류(magnetotelluric; MT) 탐사의 정확한 해석을 위해서는 특정 전기적 구조에 대한 정확한 수치적 반응을 구할 수 있는 3차원 모델링이 필수적이다. 특히, 매질내에 전기적 이방성이 있을 때는 MT 반응이 달라지므로 전기적 이방성의 영향을 고려한 MT 탐사 모델링이 필요하다. 특히, MT 탐사기법을 이용한 지열저류층의 모니터링과 같이 MT 반응의 작은 변화를 분석해야 하는 시간경과 자료의 해석의 경우, 대상 지역에 이방성이 존재할 경우 이를 고려할 수 있는 정확한 모델링이 필수적이다. 이 연구에서는 기존의 등방성만을 고려하던 유한차분법 MT 모델링 알고리듬을 수직 혹은 수평 횡등방성 이방성을 고려할 수 있도록 개선하였다. 개발한 알고리듬을 박리층 모델을 이용하여 검증한 후, 수직횡등방성 이방성이 MT 반응에 미치는 영향에 대해서 분석하였다. 향후에는 수평 횡등방성 이방성이 MT 반응에 미치는 영향에 대해서도 분석하고자 하며, 알고리듬을 더욱 발전시켜 경사 횡등방성 이방성까지 고려할 수 있도록 발전시키고자 한다.

• 한국지반환경공학회 논문집
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• 제2권3호
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• pp.81-88
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• 2001

다공질 매체의 거동은 선형 열역학적 다공 탄성 거동, 선형 다공 점성-탄성 거동, 다공소성 거동, 그리고 다공 점성-소성 거동 등으로 모형화가 된다. 또한 시간에 따라 그 거동 양상이 복합적인 형태를 띈다. 다공질 매체는 간극 속의 구성물들이 서로 상대속도를 가지며 상호 작용을 하기 때문에 coupling 효과를 고려한 다공질 매체의 변형 거동에 대한 구성모델의 개발이 필수적이다. 본 논문에서는 균질하고 등방성을 가진 재료들로 이루어진 다공질 매체의 3차원적인 거동을 포화도에 따라 완전 포화시와 부분 포화시로 나누어 연속체 다공 역학의 뼈대 위에 지배방정식들을 구한다. 또한 다공질 매체의 거동을 이해하고 해석할 수 있는 구성모델을 개발할 수 있는 토대를 마련한다. 본 연구가 확장될 경우 다공질 매체의 정확한 거동 해석과 변형량 예측이 이루어질 수 있을 것이다. 특히 도시 고형화 폐기물 매립지반의 3차원적인 거동을 해석할 수 있는 기초가 마련되어 비균질하고 이방성을 가진 재료들로 이루어진 다공질 매체 지반의 활용이 활발하게 이루어 질 것으로 기대된다.

• Journal of applied mathematics & informatics
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• 제12권1_2호
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• pp.183-198
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• 2003

We highlight the alternative presentation of the Cauchy-Riemann conditions for the analyticity of a complex variable function and consider plane equilibrium problem for an elastic transversely isotropic layer, in finite deformation. We state the fundamental problems and consider traction boundary value problem, as an example of fundamental problem-one. A simple solution of“Lame's problem”for an infinite layer is obtained. The profile of the deformed contour is given; and this depends on the order of the term used in the power series specification for the complex potential and on the material constants of the medium.

• Structural Engineering and Mechanics
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• 제56권3호
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• pp.341-354
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• 2015

The dual-phase lag heat transfer model is employed to study the problem of isotropic generalized thermoelastic medium with internal heat source. The normal mode analysis is used to obtain the exact expressions for displacement components, force stress and temperature distribution. The variations of the considered variables through the horizontal distance are illustrated graphically. The results are discussed and depicted graphically.

• Geomechanics and Engineering
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• 제3권1호
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• pp.17-28
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• 2011

This paper presents an analytical solution for steady state flow into a close-ended cylindrical permeameter. The soil medium is considered to be uniform, isotropic, and of infinite thickness. Laplace equation is solved by considering rotational symmetry and by using curvilinear coordinates obtained from conformal mapping. The deduced shape factors, which are compared to approximate relationships obtained from both numerical and physical modelling, and idealizations involving ellipsoidal cavities, are proposed for use in field measurements. It is shown that some of the shape factors obtained are significantly different from published values and show a much higher dependence of the rate of flow on the aspect ratio, than deduced from approximate solutions.

• Structural Engineering and Mechanics
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• 제29권6호
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• pp.673-687
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• 2008

In this paper, a thermo-viscoelastic problem in an infinite isotropic medium in two dimensions in the presence of a point heat source is considered. The fundamental equations of the problems of generalized thermoelasticity including heat sources in a thermo-viscoelastic media have been derived in the form of a vector matrix differential equation in the Laplace-Fourier transform domain for a two dimensional problem. These equations have been solved by the eigenvalue approach. The results have been compared to those available in the existing literature. The graphs have been drawn for different cases.

• Steel and Composite Structures
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• 제36권3호
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• pp.249-259
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• 2020

In this work, a novel three-dimensional model in the generalized thermoelasticity for a homogeneous an isotropic medium was investigated with diffusion, under the effect of thermal loading due to laser pulse in the context of Green-Lindsay theory was investigated. The normal mode analysis technique is used to solve the resulting non-dimensional equations of the problem. Numerical results for the displacement, the thermal stress, the strain, the temperature, the mass concentration, and the chemical potential distributions are represented graphically to display the effect of the thermal loading due to laser pulse and the relaxation time on the resulting quantities. Comparisons are made within the theory in the presence and absence of laser pulse.

• Structural Engineering and Mechanics
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• 제57권2호
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• pp.201-220
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• 2016

A general model of equations of the two-temperature theory of generalized thermoelasticity is applied to study the wave propagation in a fiber-reinforced magneto-thermoelastic medium in the context of the three-phase-lag model and Green-Naghdi theory without energy dissipation. The material is a homogeneous isotropic elastic half-space. The exact expression of the displacement components, force stresses, thermodynamic temperature and conductive temperature is obtained by using normal mode analysis. The variations of the considered variables with the horizontal distance are illustrated graphically. Comparisons are made with the results of the two theories in the absence and presence of a magnetic field as well as a two-temperature parameter. A comparison is also made between the results of the two theories in the absence and presence of reinforcement.