• Title/Summary/Keyword: 비등흡수

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The variations of AC dielectric breakdown strength of epoxy composites due to boiling absorption (비등흡수에 따른 에폭시 복합체의 교류 절연파괴강도의 변화)

  • 이덕진;김경민;김탁용;손인한;신성권;김경환;김재환
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.529-531
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    • 1999
  • In this Paper, the variable dielectric breakdown strengths of epoxy composites were investigated at belling absorption condition in order to observe the influences of moisture in out door use. Also. in order to improve withstand voltage properties at moisture absorbtion condition, IPN(interpenetrating polymer network) method was Introduced and the Influence was investigated. As Adding filler(SiO$_2$) classified by o(phr), 50(phr) and 100[phr] to two kinds of matrix resin, six kinds of specimens were manufactured. As a result, it was confirmed that dielectric breakdown strength wer degraded with boiling time and filer content increasing. But, it was confirmed that dielectric breakdown strength degrading rate were lowered by the Improvement of adhesion strength in IPN specimens.

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복합조직강의 제2상 형태변화에 따른 충격파괴거동에 관한 연구

  • 송삼홍;오택열
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.9 no.3
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    • pp.287-294
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    • 1985
  • 본 연구에서는 충격하중하에서 충격파괴거동에 미치는 모상입경과 제2상 형태 의 영향을 분석, 검토하기위해서, 화학성분, 마르텐사이트체적율, 연결도, 강도비등을 되도록 일정하게 하고, 우선 모상입경과 제2상의 형태(연결재와 고립재)를 변화시켜, 충격속도를 달리하였을때 얻어지는 충격하중-시간유선을 토대로하여 충격강도, 하중작 용시간, 흡수에너지 및 연성파괴거동을 고찰하였다.

Scale Down Design on Experiment Facility of the Water/Steam Receiver for Solar Power Tower (타워형 태양열 흡수기의 열전달 특성 실험장치에 관한 연구)

  • Seo, Ho-Young;Kim, Jong-Kyu;Kang, Yong-Heack;Kim, Yong-Chan
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.676-679
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    • 2007
  • This paper describes an experiment facility to measure the circulation characteristics of a water/steam receiver at various heat fluxes. The natural circulation type receiver was considered in this study. The experiment facility was designed to satisfy circulation balance with an appropriate scale down. As a result, riser tube inner diameter was 7.4 mm and water circulation was 0.319 kg/s. Downcomer tube inner diameter by circulation balance was 9.52 mm and the quality was from 0 to 0.23.

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Electronic Absorption Spectra of the Fullerene $C_{60}$:From a Molecule to Crystals (Fullerene $C_{60}$의 전자흡수 스펙트럼:분자에서 결정까지)

  • Baek, Cheong-A;Dimitriev, O.P.;Vlaskin, V.I.;Lee, Ju-Hyeon;Nam, Hee-Dong;Park, Sung
    • Korean Journal of Materials Research
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    • v.8 no.8
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    • pp.733-736
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    • 1998
  • The change of electronic absorption spectra of the fullerene $C_{60}$ in the visibJe- near UV range was examined when the molecules aggregated into different clusters such as clusters in solution and clusters in thin films. Absorption peaks were observed at 2.73 eV. These peaks did probably not come from the feature of the isolated molecules but from the direct interaction of the molecules. Absorption peaks were also observed at 3.35 eV from grained fullerene films. We think these peaks came from the interaction of the molecules at interfaces of grains. Dichroism of this absorption was also found from samples with anisotropic macrostructures.

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A Dispersive APML using Piecewise Linear Recursive Convolution for FDTD Method (FDTD법을 이용하여 분산매질을 고려하기 위한 PLRC-APML 기법)

  • Lee Jung-Yub;Lee Jeong-Hae;Kang No-Weon;Jung Hyun-Kyo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.10 s.89
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    • pp.977-982
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    • 2004
  • In this paper, a dispersive anisotropic perfectly matched layer(APML) is proposed using piecewise linear recursive convolution(PLRC) for finite difference time domain(FDTD) methods. This proposed APML can be utilized for the analysis of a nonlinear dispersive medium as absorbing boundary condition(ABC). The formulation is simple modification to the original AMPL and can be easily implemented. Also it has some advantages of the PLRC approach-fast speed, low memory cost, and easy formulation of multiple pole susceptibility. We applied this APML to 2-D propagation problems in dispersive media such as Debye and Lorentz media The results showed good absorption at boundaries.

Computational Study on the Energy Separation of the Vortex Tube for CO2 Reduction (CO2 흡수용 20Nm3/hr급 Vortex tube의 에너지 분리 현상에 관한 해석적 연구)

  • Kim, Chang-Su;Jung, Young-Chul;Han, Keun-Hee;Park, Sung-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.4
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    • pp.695-701
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    • 2009
  • Vortex tube is the device that can separate small particles from the compressed gas, as well as compressed gas into hot and cold flow. In this study, computational approach has been performed to analyze the characteristics of the vortex tube. Energy separation characteristics of the vortex tube has been tested for various geometric design parameters. For the given conditions, it is found that as the tube is lengthened, hot end temperature is reduced but cold end temperature does not influenced much. As the orifice diameter decreases, cold end temperature decreases. Also, as hot gas fraction increases, hot end temperature decreases. The results from this study can be used for the basic design parameter of the $CO_2$ reduction device.

Research on Passive Optical Devices Using Silicon on Insulator (Silicon on Insulator 수동광소자에 관한 연구)

  • 박종대
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.08a
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    • pp.156-157
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    • 2000
  • 낮은 도핑의 silicon은 광통신에서 사용하는 1.3 및 1.55 um의 광파장 영역에서 0.01dB/cm 이하의 낮은 흡수 손실을 가짐으로 인해, core 층으로 silicon을 사용하며 상부 및 하부 cladding 층으로 SiO$_2$와 같은 유전체 박막 구조를 갖는 SOI (Silicon on Insulator)를 사용한 수동광소자에 대한 연구가 1990년대부터 진행되고 있다. 또한 silicon의 특성상 SOI는strain에 의한 영향이 낮고, 광학적 비등방성이 적어서 polymer 및 silica를 이용한 광소자에 비해 편광의존도가 낮은 광소자를 구현할 수 있는 장점이 있다. 현재까지 연구되어온 SOI 수동광소자의 연구결과는 TE/TM 편광차에 따른 채널분리도가 약 0.04nm, 누화특성이 23dB 인 8채널 AWG의 연구결과가 있었으며, 스위칭시간 < 1msec, 소광비 17 dB의 광결합기와 마하젠더가 혼합된 광변조기 및 Bookham사에서 개발한 RX/TX 양방향 송수신 광모듈에 적용된 1.3/l.55 um 파장선택적 분리기, Silicon-CMOS 증폭기와 집적화된 4channel 광다중 수신기등에 대한 연구결과가 있었다. (중략)

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Fabrication of a Polymeric Planar Nano-diffraction Grating with Nonuniform Pitch for an Integrated Spectrometer Module (집적화된 분광모듈 구현을 위한 고분자 기반의 비등간격 평면나노회절격자 제작)

  • Kim, Hwan-Gi;Oh, Seung-Hun;Choi, Hyun-Yong;Park, Jun-Heon;Lee, Hyun-Yong
    • Korean Journal of Optics and Photonics
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    • v.28 no.2
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    • pp.53-58
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    • 2017
  • This paper presents the design and fabrication of a planar nano-diffraction grating for an integrated miniature spectrometer module. The proposed planar nano-diffraction grating consists of nonuniform periods, to focus the reflected beams from the grating's surface, and an asymmetrical V-shaped groove profile, to provide uniform diffraction efficiency in the wavelength range from 400 to 650 nm. Also, to fabricate the nano-diffraction grating using low-cost UV-NIL technology, we analyzed the FT-IR spectrum of a uvcurable resin and optimized the conditions for the UV curing process. Then, we precisely fabricated the polymeric nano-diffraction grating within 5 nm in dimensional accuracy. The integrated spectrometer module using the fabricated polymeric planar nano-diffraction grating provides spectral resolution of 5 nm and spectral bandwidth of 250 nm. Our integrated spectrometer module using a polymeric planar nano-diffraction grating serves as a quick and easy solution for many spectrometric applications.

Water Circulation Characteristics of a Water/Steam Receiver for Solar Power Tower System at Various Heat Fluxes (타워형 태양열 발전 흡수기의 열유속에 따른 수순환 특성 연구)

  • Seo, Ho-Young;Kim, Jong-Kyu;Kang, Yong-Heack;Kim, Yong-Chan
    • Journal of the Korean Solar Energy Society
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    • v.28 no.2
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    • pp.1-9
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    • 2008
  • This paper describes water circulation characteristics of a water/steam receiver at various heat fluxes. The water/steam receiver for a solar tower power system is a natural circulation type. Experimental conditions of water and steam were set at a pressure of 5 bar and temperature of $151.8^{\circ}C$. The experimental device for the water/steam receiver consisted of a steam drum, upper/lower header, riser tubes, and downcomer tube. The experiments were conducted by varying heat fluxes in terms of mass flow rate in each riser tube. However, the total mass flow rate on the riser tubes was fixed at 217.4 g/s. For the uniform heat flux, while the water temperature of the steam drum and upper header were kept at steady state, the temperature of the lower header was fluctuated. For the non-uniform heat flux, while the temperature of the steam drum was kept steady state, the temperature difference increased in the right and left side of the upper header, and the temperature of the lower header was fluctuated.

Radiative Heat Transfer in Discretely Heated Irregular Geometry with an Absorbing, Emitting, and An-isotropically Scattering Medium Using Combined Monte-Carlo and Finite Volume Method (몬테카를로/유한체적결합법에 의한 국소 가열되는 복잡한 형상에서의 흡수, 방사, 비등방산란 매질에 대한 복사열전달 해석)

  • Byun, Do-Young;Lee, Chang-Jin;Chang, Seon-Yong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.5
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    • pp.580-586
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    • 2004
  • The ray effects of finite volume method (FVM) or discrete ordinate method (DOM) are known to show a non-physical oscillation in solution of radiative heat transfer on a boundary. This wiggling behavior is caused by the finite discretization of the continuous control angle. This article proposes a combined procedure of the Monte-Carlo and finite-volume method (CMCFVM) for solving radiative heat transfer in absorbing, emitting, and an-isotropically scattering medium with an isolated boundary heat source. To tackle the problem, which is especially pronounced in a medium with an isolated heat source, the CMCFVM is suggested here and successfully applied to a two-dimensional circular geometry.