• Title/Summary/Keyword: 확산해석

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Study on Analytical and Empirical Methods for Assessing Geo-Heat Transfer Characteristics (지중열전달특성 평가에 관한 해석 및 실험적 방법에 관한 연구 - 지중 열물성치 및 보어 홀 열 저항 평가 -)

  • Park Jun-n;Baek Nam-Choon
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.427-432
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    • 2005
  • This study treats the advantage of in situ line source method measuring the heat transfer capacity of a borehole, using mobile equipment, to determine the thermal properties of the entire borehole system such as thermal conductivity, diffusiveity. volumetric heat capacity, and borehole thermal resistance. The results from the response test include not only the thermal properties of the ground and the borehole, but also conditions that are difficult to estimate, e,g. natural convection in the boreholes, asymmetry in the construction, etc. In this study, 1) theoretical in situ methods for assessing working fluid temperature variation in V-type PE tube have been introduced, and 2) TRTE(Thermal Response Test Equipment) has been built based on these kinds of theoretical in situ methods. Basically TRTE consists of a pump, a heater and temperature sensors for measuring the inlet and outlet temperatures of the borehole. In order to make equipment easily transportable it is set up on a small trailer. Since the response test takes above two days to execute, the test was fully automatic in recording measured data using Labview DAS(Data acquisition system) program. The test was demonstrated in the course of intensive research in this field through the one site at Ulsan city in Korea. From this kind of thermal properties test of borehole systems in situ, the design of the borehole system can be optimized regarding the total geological, hydro-geological and technical conditions at the location.

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사격장 주변 해양퇴적물내의 중금속 분포와 해양 생물체의 생흡수도에 관한 예비 고찰

  • 정현석;윤성택;최병영;정명채
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2002.04a
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    • pp.262-262
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    • 2002
  • 2001년 12월과 2002년 1월에 걸쳐 조간대 환경에 위치하는 어느 해양사격장 중위에서 일정한 간격으로 표층(<5 cm) 해양퇴적물(총22개소)과 해양생물체(굴; 총10개소)를 샘플링하고, Pb, Cu, Cd, Zn를 위시한 중금속원소의 공간적 농도 분포와 생흡수도(bioavailability)를 분석 고찰하였다. 본 논문에서는 예비 연구 결과를 간단히 소개한다. 해양퇴적물에 대한 전함량 분석, 0.1N HCl에 의한 부분 분석 및 BCR법에 의한 연속추출 분석 결과는 다음과 같다. Pb, Cu, Cd, Zn을 위시한 중금속은 대체적으로 점오염원인 사격장으로 갈수록 전함량 및 부분함량이 높아지는 경향을 보여주었다. 사격장 주변에서 가장 중요한 오염물질로 알려져 있는 Pb는 오염원 주변에서만 높은 함량을 보여주어, 해양 환경 하에서 이동도( 및 생흡수도)가 비교적 낮은 것으로 나타났다. 반면, Cu, Cd, Zn의 경우에는 보다 넓은 영역에 걸쳐 퇴적물 내의 부화(enrichment)가 인지되어 연구지역의 갯벌 환경에 의미있는 정도로 영향을 미치고 있는 것으로 나타났다. 이 곳의 생물체(굴) 역시 Pb에 대해서는 낮은 흡수도(-값의 생농축계수)를 나타낸 반면, Cu, Cd, Zn에 대해서는 의미있는 생흡수도를 나타내었다. BCR 연속추출법에 의한 퇴적물 중금속의 존재형태 해석 결과를 보면, fraction 1(F1; exchangeable+acidic phase) 및 fraction 2(F2; reducible phase)의 기여도가 지배적이고, 또한 오염원으로 갈수록 그 기여도는 점차 증가됨을 나타내었다. 특이하게도 유기물과의 친화력이 높은 것으로 알려진 Cu 역시 F1과 F2에 대하여 높은 함량을 나타내어 오염원으로부터의 Cu의 확산을 지시하였다. 외국에 비하여, 그동안 국내에서는 사격장 주변의 자연환경변화에 관하여 연구된 결과가 거의 전무하였다. 본 연구 결과는, 이와 유사한 사격장 주변 환경에서의 중금속 분포와 거동 특성에 대하여 종합적인 모니터링(즉, 체계적인 환경지구화학적 조사ㆍ연구)이 시급함을 시사해 주고 있다.

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Effects of $WSi_x$, thickness and F concentration on gate oxide characteristics in tungsten polycide gate structure (Tungsten polycide gate 구조에서 $WSi_x$ 두께와 fluorine 농도가 gate oxide 특성에 미치는 영향)

  • 김종철
    • Journal of the Korean Vacuum Society
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    • v.5 no.4
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    • pp.327-332
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    • 1996
  • In this study, the effects of $WSi_x$, thickness and fluorine concentration in tungsten polycide gate structure on gate oxide were investigated. As $WSi_x$, thickness increases, gate oxide thickness increases with fluorine incorporation in gate oxide, and time-to-breakdown($T_{BD,50%}$) of oxide decreases. The stress change with $WSi_x$ thickness was also examined. But it is understood that the dominant factor to degrade gate oxide properties is not the stress but the fluorine, incorporated during $WSi_x$ deposition, diffused into $WSiO_2$ after heat treatment. In order to understand the effect of fluorine diffusion into oxidem fluorine ion implanted gates were compared. The thickness variation and $T_{BD,50%}$ of gate oxide is saturated over 600 $\AA$ thickness of $WSi_x$. The TEM and SIMS studies show the microstructure less than 600 $\AA$ thickness is dense and flat in surface. However, over 600$\AA$, the microstructure of $WSi_x$ is divided into two parts: upper porous phase with rugged surface and lower dense phase with smmoth interface. And this upper phase is transformed into oxygen rich crystalline phase after annealing, and the fluorine is captured in this layer. Therefore, the fluorine diffusion into the gate oxide is saturated.

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Development of a Laterally Averaged 2-Dimensional Model for Saltwater Intrusion in Estuary (하구의 염수침입을 해석하기 위한 연직 2차원 수치모형 개발)

  • Lee, Jong-Uk;Lee, Bong-Hui;Jo, Yong-Sik;Yun, Tae-Hun
    • Journal of Korea Water Resources Association
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    • v.34 no.1
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    • pp.19-30
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    • 2001
  • A laterally averaged 2-dimensional hydrodynamic model is newly developed. The coordinate system is first transformed to minimize the effects of irregularity of bottom and surface. The advection terms of the governing equations are then discretized by an upwind scheme. By employing an explicit scheme for longitudinal direction and an implicit scheme for vertical direction, the model is free from restriction of temporal step size caused by a relatively small grid ratio. To demonstrate the applicability of the model, calculated time histories of free surface displacements and distributions of velocity and salinity are compared with the field measurements of the Keum River Estuary before construction of the estuary dam. A reasonable agreement is observed between them.

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Study on the deposition Characteristics of Bi Thin Film (Bi 박막의 성막 특성에 관한 연구)

  • 최철호;임중관;박용필;이화갑
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.05a
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    • pp.615-618
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    • 2003
  • This paper presents Bi thin films have been fabricated by atomic layer-by-layer deposition and co-deposition at an IBS method. The growth rates of the films was set in the region from 0.17 to 0.27 nm/min. MgO(l00) was used as a substrate. In order to appreciate stable existing region of Bi 2212 phase with temperature and ozone pressure, the substrate temperature was varied between 655 and 820 $^{\circ}C$ and the highly condensed ozone gas pressure(PO$_3$) in vacuum chamber was varied between 2.0$\times$10$^{-6}$ and 2.3$\times$10$^{-5}$ Torr. Bi 2212 phase appeared in the temperature range of 750 and 795$^{\circ}C$ and single phase of Bi 2201 existed in the lower region than 785 $^{\circ}C$. Whereas, PO$_3$ dependance on structural formation was scarcely observed regardless of the pressure variation. And high quality of c-axis oriented Bi 2212 thin film with T$_{c}$(onset) of about 90 K and T$_{c}$(zero) of about 45 K is obtained. Only a small amount of CuO in some films was observed as impurity, and no impurity phase such as CaCuO$_2$ was observed in all of the obtained films.lms.

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Nearshore Sediment Transport in Vicinity of Anmok Harbor, East Coast of Korea. (동해 안목항 주변 연안 토사이동)

  • 김인호;이정렬
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.16 no.2
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    • pp.108-119
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    • 2004
  • The breakwater extension at Anmok Harbor has resulted in erosional stresses along the wide range of shorelines immediately south of the harbor. In this study, therefore, the downdrift affects caused by the breakwater extension are investigated through both analytical and numerical approaches. In addition, this study stresses the need of monitoring and analysis system for the effective integrated coastal zone management and shows through the case study of Anmok Harbor how the numerical experiments are accomplished for the coastal zone management. The numerical model system, which predicts the seabed changes obtained from the difference between the rates of sediment pickup and settling due to gravity, is combined with the wave, wave-induced currents, and suspended sediment transport models. A new relationship between the near-bed concentration and the depth-mean concentration, which is required in estimating the settling rates. is presented by analyzing the vertical structure of concentration.

Phase Transition and Relaxation Properties of Nonlinear-Optical KTP Single Crystal (비선형광학 단결정 KTP의 상전이 및 완화특성에 관한 연구)

  • Choi, Byung-Chun
    • Journal of Sensor Science and Technology
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    • v.7 no.6
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    • pp.386-393
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    • 1998
  • We have carried out the measurements of complex dielectric constants with impedance/gain-phase analyzer using capacitor method and the experiments of high temperature X-ray powder diffraction with X-ray diffractometer using ${\theta}-2{\theta}$ scan method for the KTP single crystal which has the premium nonlinear optical properties. From the results of high temperature X-ray powder diffraction experiments, we have found that KTP does not undergo structural phase transition below $900^{\circ}C$. It is clear that KTP undergoes structural phase transition around $900^{\circ}C$ and belongs to orthorhombic above $900^{\circ}C$ still. However, we have applied phenomenological relation of dielectric relaxation to the results of complex dielectric measurement and have found that relaxation mechanism of KTP well satisfies the Cole-Cole relation over the temperature range from $-78^{\circ}C$ to $200^{\circ}C$. And also the relaxation time well satisfies the Vogel-Fulcher relation. It is regarded that the hopping and thermally activated diffusion mechanism may control the conduction behavior of KTP above $200^{\circ}C$.

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A Study on the Standard for Installation of Carbon Monoxide Detector in a Building (건축물내 일산화탄소 경보기 설치기준에 관한 연구)

  • Kang, Seung-Kyu;Choi, Kyung-Suhk
    • Journal of the Korean Institute of Gas
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    • v.12 no.4
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    • pp.1-7
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    • 2008
  • In the last five years, 36 people died and 79 were wounded because of carbon monoxide poisoning accident. A CO poisoning accident is higher than any other gas accident in the rate of deaths/incidents. Most of these CO poisoning accidents were caused by defective exhaust tube in the old gas boiler and multi-use facility. In this study, the spread mechanism of CO gas released from leakage hole of exhaust tube was analyzed by concentration measuring test. A CO gas leaked form exhaust tube in a building was the highest concentrated near the ceiling. CO alarm sets installation test confirmed that the alarm sets near the ceiling operated first, and the bottom and middle sets operated after $30{\sim}40$ minutes. Through these experiments, the reasonable installation location of CO alarm was made certain and suggested.

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A study on the electron ionization and attachment coefficients ins $SF_6$ gas ($SF_6$ 가스의 전리 및 부착계수에 관한 연구)

  • Seo, Sang-Hyeon;Yu, Heoi-Young;Kim, Sang-Nam;Ha, Sung-Chul
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.10 no.6
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    • pp.96-103
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    • 1996
  • This paper describes the electron transport characteristics in SF6 gas calculated for range of E/N values from 150~ 800[Td) by the Monte Carlo simulation and Boltzmann equation method using a set of electron collision cross sections detennined by the authors and the values of electron swarm parameters are obtained by TOF method. The results gRined that the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or Rttachment coefficients, longitudinal and transverse diffusion coefficients agree with the experimental and theoretical for a range of E/N. The properties of electron avalanches is concerned electron energy non--equilibrium region. The electron energy distributions function were analysed in sulphur hexafluoride at E/N : 500~800[Td) for a case of non-equilibrium region in the mean electron energy. The validity of the results obtained has been confilll1ed by a TOF method.

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Case Analysis of Regietheater shown in Opera Performance - With a Focus on of Komische Oper Berlin that Uses Animation - (오페라 공연에서 나타나는 레지테아터(Regietheater) 사례 분석 -애니메이션을 활용한 코미셰 오퍼 베를린 <마술피리> 프로덕션을 중심으로-)

  • Lim, Jung-eun;Kim, Hyeong-soo
    • Cartoon and Animation Studies
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    • s.51
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    • pp.1-33
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    • 2018
  • In contemporary performance arts, we can see diverse types of performances that use advanced technology and visual media. It is notable that animation based on narratives and images, is grafted on to performance arts. Cases emerge that introduce animation in opera performances as part of a new stagecraft. Regietheater that turns on directors' interpretation, has been expanded in full scale through major music festivals and theaters through many different attempts to embody. In this state, recently visual media have been actively employed in opera performances. It has led to expansion of time and space along with more attempts. Not least of all, introduction of animation has been conducive to reinforcing functionality of opera performances in many aspects. This study suggests requirements for ideal Regietheater production in opera performances. For this end, the functions of animation strategically used are evaluated through analyzing $Zauberfl{\ddot{o}}te$)> production of Komische Oper Berlin. Through this research, this study is to look deeply into effects created from new and different attempts by grafting animation on to opera performances.