• Title/Summary/Keyword: 온도경사

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Deposition of SiC/C functionally gradient materials by chemical vapour deposition (화학기상증착법(CVD)에 의한 SiC/C 경사기능재료의 증착)

  • Yootaek Kim;Nam Hun Kim;Keun Ho Orr
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.4 no.3
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    • pp.262-275
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    • 1994
  • SiC/C functionally gradient materials (FGM) were deposited on the graphite substrate by the chemical vapor deposition method. The best deposition conditions of SiC/C FGM were $1300^{\circ}C, H_2/[SiCl_4+CH_4]=10, CH_4/[$SiCl_4+CH_4]=0.5-0.6$. Despite of discontinuous input gas ratio change, the FGM of which composition was continuously changed could be obtained and continuous structural change without definite interfaces was confirmed by the SEM observation.

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Manufacturing of High Density Woodceramics by Recarbonization Using a Resin Impregnation Board - Change of Density Profile - (수지함침보드의 2차 탄화에 의한 고밀도 우드세라믹 제조 - 밀도경사 변화 -)

  • Oh, Seung-Won;Jeon, Soon-Sick;Byeon, Hee-Seop
    • Journal of the Korean Wood Science and Technology
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    • v.39 no.1
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    • pp.60-67
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    • 2011
  • A repeated impregnation and carbonization process was introduced to product high-density woodceramics using a resin impregnation board. The density profile were measured to further confirm morphologically and structurally occurred changes of one-time and two-time phenolic resin-treated and carbonized woodceramics. After the two-time carbonization of the products, the minimum, average and maximum densities increased more than those of the one-time carbonized woodceramics, and the increase of density profile. Therefore, it is considered that the preparation of uniformed woodceramics with high-density and low density dissipation can be produced by a repeated impregnation and carbonization).

Thermoelastic deformation and stress analysis of a FGM rectangular Plate (경사기능재료 사각 판의 열 탄성 변형과 응력 해석)

  • Kim,Gwi-Seop
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.1
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    • pp.34-41
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    • 2003
  • A Green's function approach is adopted for analyzing the thermoelastic deformation and stress analysis of a plate made of functionally graded materials (FGMs). The solution to the 3-dimensional steady temperature is obtained by using the laminate theory. The fundamental equations for thermoelastic problems are derived in terms of out-plane deformation and in-plane force, separately. The thermoelastic deformation and the stress distributions due to the bending and in-plane forces are analyzed by using a Green’Às function based on the Galerkin method. The eigenfunctions of the Galerkin Green's function for the thermoelastic deformation and the stress distributions are approximated in terms of a series of admissible functions that satisfy the homogeneous boundary conditions of the rectangular plate. Numerical examples are carried out and effects of material properties on thermoelastic behaviors are discussed.

Analysis of Correlationship between Topography and Ground Surface Temperature Using Landsat 7 ETM+ Satellite Data (Landsat 7 ETM+ 위성자료로부터 지형과 지표온도의 상관성 분석)

  • Lee, jin-duk;Bhang, kon-joon;Han, seung-hee
    • Proceedings of the Korea Contents Association Conference
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    • 2012.05a
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    • pp.131-132
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    • 2012
  • 서울지역을 대상으로 하여 Landsat 7 ETM+ 영상의 열적외선 채널을 이용하여 추출한 지표온도를 추출함에 있어서 DEM데이터로 부터 추출한 경사도와 사면방향 등의 지형조건과의 상관관계를 분석하고자 하였다.

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Effects of Shading Rate and Method on Inside Air Temperature Change in Greenhouses (차광율 및 차광방법이 온실내부의 온도변화에 미치는 영향)

  • 이현우;이석건;김길동;이종원
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 2001.04b
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    • pp.27-28
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    • 2001
  • 온실의 차광설계에 필요한 기초자료를 제시하기 위하여 온실모형과 실험온실을 이용하여 외부차광재의 적정 설치간격 분석, 차광재별 광투과율 분석, 차광율에 따른 온실내부온도의 변화 분석, 차광이 온실내부의 지온변화에 미치는 영향분석 및 외부차광과 내부차광의 차광효과 비교를 실시하였다. 외부경사차광시 온실 지붕과 차광재의 설치간격은 10-30cm에서 차광효율이 가장 좋은 것으로 나타났으나 환기창의 개폐를 위한 공간이 필요하지 않는 온실에서는 10cm 정도이면 충분한 간격이 될 것으로 판단된. (중략)

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Study of the Temperature Difference between the Top and Bottom Web of Steel Box Girder without Concrete Slab by using Gauge Measurement (계측에 의한 콘크리트 슬래브가 없는 강박스거더의 상하 온도차 연구)

  • Lee, Seong-Haeng
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.12
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    • pp.7350-7356
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    • 2014
  • To study the reasonable design thermal loads, a steel box girder bridge specimen, which has no concrete slab, was manufactured with real size dimensions. The temperature data was obtained at the web and diaphragm using thermo gauges that were attached according to height. In the hottest day, the temperature differences between the top and bottom of the bridge model were calculated. The temperatures in the actual bridge were measured and the temperature of the bridge specimen was compared. The temperature gradient models were proposed in both the web and the diaphragm. The proposed models showed a correlation of approximately 95.8% compared to the Euro code. This study can provide basis data for temperature-load design in the nation.

Relationship Analysis between Lithology, Geological time and Geothermal Gradient of South Korea (남한지역의 암상 및 지질시대별 지온경사율 관계 분석)

  • 김형찬;이사로;송무영
    • Economic and Environmental Geology
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    • v.35 no.2
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    • pp.163-170
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    • 2002
  • The purpose of this study is to analyze the relationship between geology and geothermal gradient in South Korea using GIS. For the analysis, 352 temperature logging wells were constructed to spatial database and the relationships beween geothermal gradient and geological time and lithology were analyzed using the overlay the wells layer and 1:1,000,000 scale geological map layer. The average of the geothermal aradient of South Korea is 29.34$^{\circ}C$/km. In the geologic sequence, Cenozoic strata has 39.7$0^{\circ}C$/km, Mesozoic strata has 30.63$^{\circ}C$/km , Paleozoic strata has 22.32$^{\circ}C$/km, Proterozoic strata 23.15$^{\circ}C$/km geothermal gradient value. In the lithological aspect, plutonic rocks 33.96$^{\circ}C$/km, sedimentary rocks have 24.78$^{\circ}C$/km and sedimentary and volcanic rocks have 26.85$^{\circ}C$/km geotermal gradient value. The result can be used to develop geothermal energy and hot spring as a reference.