• Title/Summary/Keyword: Integrated emissivity

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Thermal Radiative Properties of Multilayer Graphene/Glass Structure (다층 그래핀/유리 구조체의 적외선 열복사 특성 연구)

  • Park, Kyung-Ah;Lim, Mikyung;Jung, Hyun-June;Kim, Jae-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.34 no.1
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    • pp.27-32
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    • 2021
  • In this study, we fabricated multilayer graphene on a glass substrate by stacking the monolayer graphene synthesized via chemical vapor deposition. The electrical sheet resistance and optical transmittance were evaluated to confirm the quality of the stacked multilayer graphene. Using the fabricated multilayer graphene/glass structure, we characterized its thermal radiative property in terms of the integrated emissivity. The integrated emissivity of the multilayer graphene/glass structure was tuned from 0.91 to 0.72 when the number of graphene layers was changed from 1 to 12. We also demonstrated that the emissivity tunability provided a way to control the apparent temperature of an object that can be used in infrared stealth applications.

Analysis of absorption and scattering characteristics of alumina particles using Mie theory (Mie Theory를 이용한 알루미나 입자의 흡수 및 산란 특성 분석)

  • Ko, Ju-Yong;Kim, In-Sun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.962-967
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    • 2011
  • Radiative properties of alumina particles which is the main element of the plume from booster and kick motor used for increasing thrust and insertion into the orbit is analyzed. In order to derive the wavelength integrated (i.e., gray) emissivity, emission term in radiative transfer equation is rearranged to be able to tie up with the parameters induced from fundamental particle scattering Mie theory. Result shows that derived gray emissivity with optical properties increases with temperature rising.

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Estimation of Surface Temperature of the Urban Area in Cheongju Using ASTER Data (ASTER에 의한 청주시주변의 지표면온도 추정)

  • Park, Jong-Hwa;Na, Sang-Il
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2005.10a
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    • pp.563-568
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    • 2005
  • Land surface temperature (LST) for large areas can only be derived from surface-leaving radiation measured by satellite sensors. These measurements represent the integrated effect of the surface and are superior to point measurements on the ground, e.g. in Urban Heat Island. ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is an imaging instrument that is flying on the NASA's Terra satellite launched in December 1999. ASTER acquires 14 spectral bands and can be used to obtain detailed datas of land surface temperature, emissivity, reflectance and elevation. Spatial resolution of 90m of TIR channels of ASTER is useful when we analyze the spatial variations of surface heat fluxes in urban areas. The purpose of this study is to extract the LST using ASTER TIR channels.

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A Study on Far-infrared Radiation and Proliferation of Ocherous Cotton Quilt Fabrics (황토를 부착한 이불 면 원단의 원적외선 방출량 및 생균의 분리 동정 연구)

  • Lee, Ku Yeon;Lee, Hyung H.;Hahm, Suk Chan
    • Journal of Naturopathy
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    • v.8 no.2
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    • pp.71-77
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    • 2019
  • Purpose: The purpose of this study was to investigate the far-infrared emissivity of patented ocher quilt cotton fabrics and to investigate the microorganisms that survived the washing of cotton fabrics up to 20 times. Methods: A 16S rRNA assay was performed using a far-infrared radiometer and a single colony in which microorganisms grew in nutrient media. Results: The far-infrared emissivity of ocher quilt was 0.902 (90.2%) at 5~20 ㎛ at 40℃, and the radiation energy was 3.63 × 102 w/m2. The number of viable cells was 2.0 × 102 cells/ml in ocher duvet cotton fabric, and no viable bacteria found in regular cotton fabric. The base sequence of 16S rRNA of B-2 strain isolated into single colonies was 1,419 bases, and the base sequence of strain A-4 was 1,284 bases. The base sequence of 16S rRNA of these two strains showed high homology with Bacillus spp. The B-2 bacteria showed high homology with 99.0% of the 16S rRNA sequence of B. aryabhattai EF114313 and 99.0% of the A-4 bacteria of B. bingmayongensis AKCS01000011. Consequently the colony strain B-2 finally identified as B. aryabhattai BJ-2 and A-4 as B. bingmayongensis BJ-4 strain. Concusions: Soil Bacillus strains survived in ocher quilt cotton fabric after 20 washing. The material can be useful because quilt cotton fabric emits a large amount of far-infrared and far-infrared radiation energy.