• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.135-138
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• 2005

최근에 ELLAM 기법을 이용한 오염물 거동 문제를 많은 사람들이 다루어 오고 있다. ELLAM 기법은 기존의 Eulerian-Lagrangian 방식에서 일어나는 질량보존 문제점과 일반경계조건의 체계적인 적용 한계점을 극복하였다. 그러나 본 연구에서는 이 방식의 장단점을 네 개의 예제를 통하여 다른 모델들과 비교 검토하여 ELLAM의 수치적 고찰을 수행하고자 한다. 예제 수행 결과 Mesh Peclet Number가 무한대일때 ELLAM은 수치확산 및 수치진동과 같은 수치오차로 인해 음수의 농도 값을 갖거나 1 보다 큰 농도를 갖는 경향을 보인다. 그러나 Mesh Peclet Number 50 일때는 전체적으로 해석해와 잘 일치함을 볼 수 있다. 반면, LEZOOMPC(Lagrangian-Eulerian ZOOMing Peak and valley Capturing)는 항상 좋은 결과를 보여주고 있다. 따라서 위의 결과를 종합하여 볼 패 ELLAM의 단점은 LEZOOMPC의 성질을 이용하여 개선 및 보완될 수 있음을 간접적으로 시사해준다. 즉 LEZOOMPC에서 사용되는 선택적 국부 격자 세립화 과정을 이용하면 ELLAM에시 일어나는 다양한 수치오차를 줄일 수 있을 것이라고 판단된다.

• Water for future
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• v.24 no.1
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• pp.99-107
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• 1991

This study is for simulating to the model which analyzes flow characteristics and transverse bed slopes in a coarse-streambed of the meandering alluvial channels. Using the equations for conservation of mass, momentum, and for lateral stability of the streambed, a linear differential equation of transverse bed slope is derived from the flow characteristics in curved channels. Its solutions are solved by the Sine-generated curve method(SCM) and compared with results of field measurements. Lag distances by the maximum transverse bed slope and velocity profiles will predict risk sections of concave bank under floods.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1268-1271
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• 2007

트렌치 수로에서 동수압을 고려한 자유수면 흐름을 해석하고 난류 모형의 적용성을 제시하였다. 본 연구에 사용된 지배방정식으로 비정상 상태의 비압축성 유체에 대한 연속방정식과 비점성 Navier-Stokes 방정식을 사용하였다. 난류완결문제를 해결하기 위해서 $\kappa-\varepsilon$방정식을 사용하여서 난류 와점성을 구할 수 있다. 자유수면과 동수압을 고려하기 위하여 3단계로 나누어서 해석하였다. 제 1단계에서는 운동량방정식을 연직방향에 대해 음해적으로 차분하였다. 제2단계에서는 유속과 동수압 보정항으로 이루어진 식을 연속방정식에 대입하여 타원형 방정식인 동수압-포와송 방정식을 해석하여 얻어지는 유속은 질량보존법칙을 만족하게 된다. 마지막으로 자유수면과 최종유속을 보정 및 계산하였다. 본 연구에서 제시한 수치모형을 검증하기 위해서, 트렌치 수로에서 난류의 흐름에 변화를 고려하기 위해 수치모의를 하였다. 전반적으로 수치모의에 의한 결과와 실험 자료가 일치하는 경향을 보였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.65-67
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• 2017

Various combustion modeling approaches have been developed and verified in a combustion system such as rockets, gas turbines, and so on. This study introduces basic theory and recent research activities on 1D network model where a system is divided into a series of acoustic element and mass/momemtum/energy conservations are applied in the component. Each component is connected to the neighboring ones with proper jump conditions. Flame transfer function and acoustic transfer function are determined and effects of the each function on the system instability is investigated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.10
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• pp.1048-1053
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• 2009

It proposes an simple and intuitive method that calculates the equilibrium pressures of a propellant tank by appling the mass conservation principle on the helium in the liquid propellant and in an ullage volume of the propellant tank. A propellant loading analysis program is developed and validated against the existing reference data. And it has applied to the present developing program, COMS Chemical Propulsion Subsystem and the results are compared, it may use to develop a technology of the next geostationary complex satellite's propulsion system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.04a
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• pp.10-10
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• 1999

선형 및 비선형 GPA 기법을 이용한 가스터빈 엔진의 성능예측 및 진단을 연구하고 전형적 산업용 가스터빈 엔진인 TB5000에 적용하여 최적의 계측변수를 정의하였다. 선형 GPA는 가스가 지나가는 구성품의 계측가능한 온도, 압력, 연료유량, 로터 회전수 등과 같은 종속변수와 효율, 유량과 같은 측정불가능한 독립변수의 관계 방정식을 열역학 법칙, 연속방정식, 질량 및 에너지 보존법칙, 구성품 성능곡선 등으로부터 유도하는 것이며 비선형 GPA는 독립변수와 종속변수의 비선형 관계를 충분히 고려하기 위해 선형 GPA를 반복적으로 적용하는 방법이다. 본 연구에서 반복기법은 Newton-Raphson 반복기법을 사용하였다.

• Journal of Conservation Science
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• v.28 no.4
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• pp.395-401
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• 2012

To investigate bioactive materials for development of natural conservative agent on organic cultural heritage, essential oil from Asarum sieboldii was screened for antifungal and insecticidal activity against 4 wood rotting fungi and adult of Lasioderma serricorne. Antifungal activity of essential oil was tested by using paper disc soaking method. Antifungal activity expressed as $IC_{50}$ value showed $1.50{\sim}2.84{\mu}l/disc$ range and the most significant antifungal activity was observed in Lentinus lepideus. The insecticidal activity of essential oil was examined by topical application method against L. serricorne adults. 50% and 100% of essential oil gave 98.3% and 100% mortality for 24 hours, respectively. The major components of the essential oil were methyl eugenol (56.32%), eucarvone (11.53%), safrole (5.79%), ${\delta}$-3-carene (2.09%), which were identified by gas chromatography-mass spectrometry. From these results, essential oil from A. sieboldii could be useful for conservation of organic cultural heritage against biological deterioration by insect and wood rotting fungi.

• Korean Journal of Heritage: History & Science
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• v.56 no.3
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• pp.158-171
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• 2023

Pottery filled with organic materials was excavated from the G-2 building site of Yongjangseong Fortress, Jingo, a relic of the Goryeo Dynasty. In this study, the characteristics of organic material were confirmed by a scientific analysis of organic material in pottery found at the palace in Yongjangseong, Jindo. In addition, it was intended to review the analysis method to identify the natural resin and to secure characteristic components(biomarkers) for each natural resin and use them as basic data in the future. The organic materials in the pottery were analyzed using attenuated total reflectance Fourier-transformed infrared spectroscopy(ATR-FTIR) and gas chromatography mass spectrometry(GC-MS). The infrared spectral characteristics were estimated to be natural resin, and biomarkers of organic materials were identified as sesquiterpene-based compounds(C₁₅H₂₄, MW 204) and derivatives. The lacquer(T.vemicifluum) is composed mainly of alkenes, alkanes, and catechol. Pine resin(P.densiflora), on the other hand, is primarily composed of diterpenoid(abietic acid, pimaric acid) and Whangchil(yellow lacquer) is identified to have sesquiterpenes(such as selinene, muurolene, calamenene) as its main components. So, the organic material in the pottery can be identified as Whangchil by comparing their compounds with modern resin materials from Dendropanax. morbifera that correspond with the results. Whangchil, which is exuded from the Dendropanax. morbifera, has been used as a natural coating materials since ancient times, and it has been confirmed that the characteristic components are well preserved even 700 years later. It can be assumed that the interior Whangchil was stored not for use as a coating, but rather for ritual purposes when the building was constructed, because the pottery was found near the cornerstone. Furthermore, based on simplified sample preparation using pyrolysis-gas chromatography mass spectrometry(Py-GC-MS), the thermal decomposition products were found to be similar to the characteristic components, suggesting that this method can be applied to the identification of natural resins used in historic artifacts.

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.71-78
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• 2013

In this paper, the golf club head hit the golf ball moves at a constant velocity, then move in the same direction at a constant velocity of the golf club head, the velocity of the golf ball was hitting and flying the golf ball is calculated. If velocity is different before you hit the golf ball, each of the velocity of the golf ball is calculated. The purpose of this paper is to make it easy to find out the velocity of a club's head, the mass of a golf ball, the velocity or the direction of a golf ball after impact in playing golf. The results of the experiment are represented in tables and figures. And we also propose the comparison analysis between our research and other traditional ones, the implications, and futhur studies in the future. The results of this study, unlike other studies, it was can be seen that measurements of several factors superior to the measurement of the velocity of the golf ball.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.1 no.1
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• pp.15-22
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• 2000

There are lots of industrial machines of which functions are achieved by operation of multi-phase fluids. Some of them take advantage of the characteristics of counter-current two-phase flow The maximum flow rates of gas and liquid phases which flow in opposite-directions (counter-current flow) are limited by a phenomenon known as a Counter-Current Flow Limitation (CCFL or Flooding) The mass and momentum conservation equations for each Phase were established to build a first-order hyperbolic partial derivative equations system. A new CCFL model is developed based on the characteristic equation of the hyperbolic PDE system. The present model has its applicationto the case in which a non-uniform flow is developed around a square or sharp-edged entrance of liquid phase. The model is able to he used to Predict the operating-limit of components in which mass and heat transfer are taking place between liquid and gas phases.