• 한국해양공학회지
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• 제26권2호
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• pp.39-47
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• 2012

The objective of this study was to develop a strength prediction model using a polynomial regression analysis based on the experimental results obtained from ninety samples. As the results of a correlation analysis between various mixing factors and unconfined compressive strength using SPSS (statistical package for the social sciences), the governing factors in the strength of lightweight soil were found to be the crumb rubber content, bottom ash content,and water-cement ratio. After selecting the governing factors affecting the strength through the correlation analysis, a strength prediction model, which consisted of the selected governing factors, was developed using the polynomial regression analysis. The strengths calculated from the proposed model were similar to those resulting from laboratory tests (R2=87.5%). Therefore, the proposed model can be used to predict the strength of lightweight mixtures with various mixing ratios without time-consuming experimental tests.

• Structural Engineering and Mechanics
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• 제71권1호
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• pp.23-35
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• 2019

In this study we derive the governing equations of a functionally graded piezoelectric disk, subjected to thermo-electro-mechanical loads. First order shear deformation theory is used for description of displacement field. Principles of minimum potential energy is used to derive governing equations in terms of components of the displacement field and the electric potential. The governing equations are derived for a disk with variable thickness. The numerical results are presented in terms of important parameters of the problem such as profile of variable thickness, in-homogeneous index and other related parameters.

• Structural Engineering and Mechanics
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• 제81권6호
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• pp.705-714
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• 2022

The aim of this paper is to investigate nonlinear dynamic responses of functionally graded composite beam resting on the nonlinear viscoelastic foundation subjected to moving mass with temperature rising. The non-linear strain-displacement relationship is considered in the finite strain theory and the governing nonlinear dynamic equation is obtained by using the Hamilton's principle. The Galerkin's decomposition technique is utilized to discretize the governing nonlinear partial differential equation to nonlinear ordinary differential equation and then the governing equation is solved by using of multiple time scale method. The influences of temperature rising, material distribution parameter, nonlinear viscoelastic foundation parameters, magnitude and velocity of the moving mass on the nonlinear dynamic responses are investigated. Also, the buckling temperatures of the functionally graded beams based on the finite strain theory are obtained.

• 한국산학기술학회논문지
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• 제9권1호
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• pp.143-153
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• 2008

최근 구도심내 청사(廳舍)의 이전과 함께 도심 내 읍치시설(邑治施設)의 발굴 및 복원에 대한 관심이 증대되고 있고, 보전 또는 활용 가능한 읍치를 사적으로 지정하려는 움직임도 대두되고 있다. 이러한 읍치시설의 복원 혹은 재정비와 함께 제기되는 문제의 하나는 그의 활용문제라 할 수 있고, 이와 관련하여 조선시대 관찰사(觀察使)와 관련된 각종 의례(儀禮)나 행사의 재현이 주목되고 있다. 그러나 이러한 점증하는 요구에 비하여 관련 자료의 발굴과 연구는 대단히 부족한 형편이다. 본 연구는 18세기 충청도(忠淸道)를 대상으로 충청감사(忠淸監司)가 작성한 사료인 일기(日記) ($\ulcorner$충청감영일기(忠淸監營日記$\lrcorner$, $\ulcorner$호서감영일기(湖西監營日記)$\lrcorner$ $\ulcorner$금영일기(錦營日記)$\lrcorner$)를 분석하여 감사(監司)의 도임(到任)과 교구(交龜), 감영처(監營處)에서의 집무(執務) 및 행례(行禮)와 관련된 감영시설(監營施設)의 실패적 이용 상황은 물론 감사(監司)의 순역(巡歷)과 관련지어 순역(巡歷) 행로(行路)와 순역시(巡歷時) 도내(道內) 각 읍치(邑治)에서 실재 행해진 행례(行禮)에 대해 살펴보는 것을 목표로 하였다. 본 연구의 결과가 각 도별로 확대되면 각 도 관찰사와 연관된 읍치시설 활용 및 행례의 각 도별 공통점과 특수한 점들이 드러날 수 있을 것이며, 이는 각 읍치시설의 활용과 각종 행례 재현에 실증적 기초 자료가 될 것이다.

• 한국자원식물학회지
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• 제28권1호
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• pp.16-25
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• 2015

온주밀감 60품종에 대하여 착색 개시기에 과즙의 플라보노이드 조성 및 함량을 분석하고 품종들과의 연관관계를 조사하였다. 온주밀감 과즙에서는 flavanones에 속하는 narirutin, hesperidin과, flavones인 rutin, polymethoxylated flavones인 sinensetin, tangeretin, nobiletin 등 6종을 함유하고 있는 것으로 나타났다. 온주밀감 과즙 중에는 narirutin, hesperidin 함량이 가장 높아 대표적인 기능성 성분으로 나타났으며, 기능성이 우수한 polymethoxylated flavones인 sinensetin, tangeretin, nobiletin도 함유하고 있었다. Hesperidin 함량 범위는 41~196 mg/L로, narirutin 함량은 25~230 mg/L로 나타났다. Rutin 함량은 평균 2.2 mg/L로 미량이 검출되었고 일부 품종에서는 전혀 검출이 이루어지지 않았다. 감귤에 특이적으로 나타나는 polymethoxylated flavones류인 sinensetin, nobiletin, tangeretin은 미량이지만 모든 품종에서 검출되었다. 온주밀감 과즙 중에 함유된 플라보노이드 조성 및 함량과 품종의 수확기와의 연관성을 분석하고자 R 프로그램으로 계층적 군집분석을 실시한 결과, 플라보노이드 성분별 함량에 따라 A, B1, B2 집단으로 구분할 수 있었으나 세집단 모두에서 극조생온주밀감, 조생온주밀감, 보통온주밀감이 산재하여 있어 착색개시기 과즙 중 플라보노이드 분포와 과실의 성숙기와는 관련성이 적은 것으로 나타났다.

• 한국자원식물학회지
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• 제21권5호
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• pp.347-351
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• 2008

뿌리에 진통, 진정, 건위, 구충 효능이 있다고 알려진 석창포(Acorus gramineus Soland)의 확대재배를 위하여 현재 분근증식만으로 한정되어 있는 번식법을 개선하고자 종자번식과 기내배양에 의한 번식 방법을 검토하였다. 종자번식을 위한 수확적기는 종피가 연녹색을 띠었을 때가 적합하였으며, 종자의 보관은 $5^{\circ}C$에서 30일까지 저장하는 것이 발아율을 높게 유지할 수 있었다. 석창포의 기내발아에는 $2.0mg{\cdot}L^{-1}$ NAA와 $0.1mg{\cdot}L^{-1}$ BA를 MS 기본배지에 첨가하여 다수의 신초를 유도한 후, $0.1mg{\cdot}L^{-1}$ BA 단독 처리 및 $0.5mg{\cdot}L^{-1}$ NAA와 $1.0mg{\cdot}L^{-1}$ BA 혼합처리에서 발근을 유도하는 것이 효과적이었다. 석창포 육묘상토로는 vermiculite보다 원예상토가 생육이 우수하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권3호
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• pp.25-36
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• 2021

This study evaluated monthly, seasonal and altitudinal changes of oxygen and hydrogen isotope compositions of wet precipitation samples (n = 238) that were collected for last four years from 7 altitudes (from 265 to 1,500 m above sea level) in the Jeju Samdasoo watershed at the southeastern part of Jeju island, in order to examine the recharge characteristics of groundwater that is pumped out for the production of the Samdasoo drinking mineral water. Precipitation samples showed a clear seasonal change of O-H isotopic composition as follow, due to the different air masses and relative humidity: 𝛿D = 7.3𝛿¹⁸O + 11.3 (R² = 0.76) in the wet season (June to September), while 𝛿D = 7.9𝛿¹⁸O + 9.5 (R² = 0.91) in the dry season (October to May). In contrast, the stable isotope compositions of groundwater were nearly constant throughout the year and did not show a distinct monthly or seasonal change, implying the well-mixing of infiltrated water during and after its recharge. An altitudinal effect of the oxygen isotope compositions of precipitation was also remarkable with the decrease of -0.19‰ (R² = 0.91) with the elevation increase by 100 m. Based on the observed altitudinal change, the minimum altitude of groundwater recharge was estimated as 1,200 m above the sea level in the Jeju Samdasoo watershed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.314-316
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• 2011

This paper develops a spectral element model for the composite beams with a surface-bonded piezoelectric layer from the governing equations of motion. The governing equations of motion are derived from Hamilton's principle by applying the Bernoulli-Euler beam theory for the bending vibration and the elementary rod theory for the longitudinal vibration of the composite beams. For the PZT layer, the Bernoulli-Euler beam theory and linear piezoelectricity theory are applied. The high accuracy of the present spectral element model is evaluated through the numerical examples by comparing with the finite element analysis results.

• 한국실내디자인학회논문집
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• 제12호
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• pp.18-24
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• 1997

The purpose of this study is to design a new self-governing body's civil service office ahead the period of provincial autonomy. The present civil service office has a linear and contrary structure and conglomates a single unit. But a new civil service office must have a comfortable structure, dividing a minimum unit per department, equpping a ordinary entrance, a creative image, a warm environment and a curved and orthogonal form.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1993년도 지하공간 건설기술에 관한 서울 심포지움 논문집
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• pp.133-162
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• 1993

The environment of underground spaces might be considered in view of working environment during the construction and living environment after completion of the construction work. For controlling environment of underground space, an appropriate measures have to be taken on the governing factors such as air flow, dust, gases, heat, radiation, noise, illumination and water. The more critical matter, in underground environmental point of view, is underground disasters such as fire, gas explosion and water inrush. This paper presents the general introduction of these factors mentioned above and some outcomes of research works as of now.