• 자원ㆍ환경경제연구
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• 제20권1호
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• pp.33-60
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• 2011

본 연구의 목적은 생산 프론티어 접근을 통하여 OECD 국가의 에너지효율과 경제성장이 에너지수요에 미치는 영향을 비교하는 것이다. 본 연구는 OECD 국가를 대상으로 전통적 에너지 원단위와 생산 프론티어 접근에 의한 에너지효율, 생산 프론티어 상의 효율점에서 에너지 과다 여유분의 존재, 생산의 기술구조 하에서 GDP 증가에 따른 에너지수요 탄력성을 살펴보았다. 첫째, 전통적 에너지 원단위는 방사선 에너지효율과는 상관성이 낮고 여유분 에너지효율, 비방사선 에너지효율과 에너지 최소화 방향의 수평선 에너지효율 등과는 일정한 상관성을 보인다. 에너지 원단위만으로 에너지효율 여부를 판단하는 것은 오류가 있을 수 있다. 특히 방사선 효율에 의한 에너지효율은 대부분의 국가의 에너지효율을 과대평가하는 경향이 있다. 둘째, OECD 국가들이 프론티어 상의 효율적인 생산점에서도 불필요하게 에너지를 소비하는 것이 연평균 17.3%이므로 에너지의 추가 저감이 필요하다. 셋째, OECD 국가의 경제성장에 대한 에너지 탄력성의 평균은 1.1로서 거의 단위 탄력성에 가깝다. 탄력성의 국가별 차이는 존재하고 탄력성이 높은 국가의 에너지수요는 높다.

• Nuclear Engineering and Technology
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• 제51권6호
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• pp.1689-1695
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• 2019

This study suggests a simple economic model to analyze electricity grid that consists of different power sources. The substitutability of renewable energy for nuclear power in Korean electricity transmission network is investigated by suggested model. The monthly data from January 2006 to December 2013 reported by Electricity Power Statistics Information System (EPSIS) of Korea Power EXchange (KPX) are used. To estimate the elasticities of substitution among four power sources (i.e. coal, natural gas, nuclear power, and renewable energy), this paper uses the trans-log cost function model on which local concavity restrictions are imposed. The estimated Hicks-Allen and Morishima elasticity of substitution shows that renewable electricity and nuclear power are complementary. The results also evidenced that renewable electricity and fossil fueled thermal power generation are substitutes.

• Advances in materials Research
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• 제11권1호
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• pp.41-57
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• 2022

This paper is focused on delamination analysis of a multilayered inhomogeneous viscoelastic beam subjected to linear creep under constant applied stress. The viscoelastic model that is used to treat the creep consists of consecutively connected units. Each unit consists of one spring and two dashpots. The number of units in the model is arbitrary. The modulus of elasticity of the spring in each unit changes with time. Besides, the modulii of elasticity and the coefficients of viscosity change continuously along the thickness, width and length in each layer since the material is continuously inhomogeneous in each layer of the beam. A time-dependent solution to the strain energy release rate for the delamination is derived. A time-dependent solution to the J-integral is derived too. A parametric analysis of the strain energy release rate is carried-out by applying the solution derived. The influence of various factors such as creep, material inhomogeneity, the change of the modulii of elasticity with time and the number of units in the viscoelastic model on the strain energy release rate are clarified.

• 에너지공학
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• 제21권3호
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• pp.301-308
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• 2012

본 논문은 수송용 LPG 수요함수를 추정하고 장 단기 가격 및 소득탄력성을 분석한다. 또한 추정된 장기 가격탄력성을 활용하여 수송용 LPG 소비로 발생하는 소비자 잉여 및 경제적 편익을 추정한다. 분석에 사용된 가격 및 소득 자료는 각각 2003년부터 2012년까지의 소비자 물가지수로 조정한 월별 실질 수송용 LPG 가격과 월별 경기종합지수이다. 수요함수의 추정을 위해 단위근 검정, 공적분 검정, 오차수정모형 추정의 절차를 취했다. 수송용 LPG 수요는 가격에 비탄력적인 것으로 판단되며 단기보다는 장기가 보다 탄력적이다. 수송용 LPG 수요의 장기 가격탄력성은 -0.422였으며, 이를 이용하여 계산된 수송용 LPG 소비의 소비자 잉여와 경제적 가치는 2012년 3월의 경우 각각 9,660억원 및 1조 7,813억원에 달한다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.65-66
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• 2002

One aspect of the stiction problem may be explained by the action of capillary forces in conjunction with surface elasticity. In the present work, the interaction between two elastic half-spaces separated by a small liquid bridge is investigated. By minimizing the total free energy stored in the interface (including elastic energy and surface energy), the equilibrium interface geometry is determined analytically in the case where there is no solid-solid contact. A non-dimensional number, $N_c=299\frac{{\gamma}^2_{LA}cos^2{\theta}V_o}{E^{'2}H^5}$ is found to govern the structure stability. When $N_c{\ge}1$, the two surfaces jump into solid-solid contact and, once this occurs, the contact area will continue to expand until the two surfaces are in full contact.

• 한국기술혁신학회:학술대회논문집
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• 한국기술혁신학회 2010년도 춘계 학술대회 논문집
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• pp.3-14
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• 2010

Through time-series plots, we can see relatively stable trend of energy factor share and the decreasing trend of relative energy prices (to wages) in Korea. We can compromise these empirical facts with the following explanation: if elasticity of substitution between capital and energy is smaller than one(<1) in Korea, a change(decrease) in energy price can prevent income share of resources from rising in the process of economic growth. This is consistent with theoretical and empirical results that substitution between energy and capital is so difficult. From simple empirical analysis and limited information, we can carefully infer that, in the past in Korea, resource-specific innovation was performed widely. Finally, If we are to reduce the magnitude of "growth drag", we should decrease energy factor share. This can be accomplished by energy-augmenting technical progress in the case of elasticity of substitution less than 1 as in Korea.

• 에너지공학
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• 제11권2호
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• pp.142-148
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• 2002

경쟁적인 전력시장에서 실시간 전력가격의 변화는 전력소비자들의 전력소비에 영향을 주게된다. 서로 다른 특성을 가지는 가정용, 상업용, 산업용 부하들은 전력소비 성향의 변화에 따라 서로 다른 가지 탄력성을 가진다. 따라서, 본 논문에서는 계산된 각 용도별 부하에 대한 수요 탄력성을 적용하여 경쟁 전력시장에서 수요 탄력성에 따른 전력수요의 변화가 현물가격에 미치는 영향을 분석한다.

• Structural Engineering and Mechanics
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• 제13권3호
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• pp.261-276
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• 2002

A novel, 6-node, two-dimensional mixed finite element (FE) model has been developed to analyze laminated composite beams by using the minimum potential energy principle. The model has been formulated by considering four degrees of freedom (two displacement components u, w and two transverse stress components ${\sigma}_z$, $\tau_{xz}$) per node. The transverse stress components have been invoked as nodal degrees of freedom by using the fundamental elasticity equations. Thus, the present mixed finite element model not only ensures the continuity of transverse stress and displacement fields through the thickness of the laminated beams but also maintains the fundamental elasticity relationship between the components of stress, strain and displacement fields throughout the elastic continuum. This is an important feature of the present formulation, which has not been observed in various mixed formulations available in the literature. Results obtained from the model have been shown to be in excellent agreement with the elasticity solutions for thin as well as thick laminated composite beams. A few results for a cross-ply beam under fixed support conditions are also presented.

• Structural Engineering and Mechanics
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• 제73권3호
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• pp.287-302
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• 2020

This investigation deals with a size-dependent coupled thermoelasticity analysis based on Green-Naghdi (GN) theory in nano scale using a new modified nonlocal model of heat conduction, which is based on the GN theory and nonlocal Eringen theory of elasticity. In the analysis based on the proposed model, the nonlocality is taken into account in both heat conduction and elasticity. The governing equations including the equations of motion and the energy balance equation are derived using the proposed model in a nano beam resonator. An analytical solution is proposed for the problem using the Laplace transform technique and Talbot technique for inversion to time domain. It is assumed that the nano beam is subjected to sinusoidal thermal shock loading, which is applied on the one of beam ends. The transient behaviors of fields' quantities such as lateral deflection and temperature are studied in detail. Also, the effects of small scale parameter on the dynamic behaviors of lateral deflection and temperature are obtained and assessed for the problem. The proposed GN-based model, analytical solution and data are verified and also compared with reported data obtained from GN coupled thermoelasticity analysis without considering the nonlocality in heat conduction in a nano beam.

• Nuclear Engineering and Technology
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• 제47권4호
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• pp.500-511
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• 2015

In this study, the natural frequencies of the perforated square plate with a square penetration pattern are obtained as a function of ligament efficiency using the commercial finite-element analysis code ANSYS. In addition, they are used to extract the effective modulus of elasticity under an assumption of a constant Poisson's ratio. The effective modulus of elasticity of the fully perforated square plate is applied to the modal analysis of a partially perforated square plate using a homogeneous finite-element analysis model. The natural frequencies and the corresponding mode shapes of the homogeneous model are compared with the results of the detailed finite-element analysis model of the partially perforated square plate to check the validity of the effective modulus of elasticity. In addition, the theoretical method to calculate the natural frequencies of a partially perforated square plate with fixed edges is suggested according to the Rayleigh-Ritz method.