• 방재와보험
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• s.112
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• pp.51-58
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• 2006

지난 호에 이어 이번 호에는 SFPE 방화공학핸드북의 제4부, 제9장 및 제11장에서 설명하고 있는 내화피복 강부재와 내력 목재 부재의 내화성능 계산방법에 대해서 소개하고, 제3부, 제11장에서 다루는 개방형 탄화수소 화재의 복사열선속을 계산하는 방법과, 이러한 복사열선속의 인체 위험성(제2부, 제6장)에 대해 소개한다

• The Optical Journal
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• s.122
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• pp.18-19
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• 2009

10여년전 IMF 이후 성장이 정체된 복사기의 국내시장은 그 동안 디지털화를 기점으로 하여 컬러화, 서비스 비즈니스 솔루션의 개발, 디지털인쇄시장 진입 등 새로운 시장을 개척하며 사업의 다각화를 꾸준하게 노력하고 있으나, 결국 한정된 국내시장에서 업체 상호간에 생존을 위한 치열한 경쟁을 할 수밖에 없는 상황이다. 이러한 여건 속에서 복사기업계에서 안고 있는 고질적인 문제가 전혀 해결되지 않고 있어 이중삼중의 고통을 겪고 있다.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.21 no.1
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• pp.31-46
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• 1993

A radiative transfer model with two-stream/delta-Eddington approximation has been developed to calculate the vertical distributions of atmospheric heating rates and radiative fluxes. The performance of the model has been evaluated by comparison with the results of ICRCCM (Intercomparison of radiative codes in climate models). It has been demonstrated that the presented model has a capability to calculate the solar radiation not only accurately but also economically. The characteristics of ultraviolet-B radiation (UV-B; 280-320nm) are examined by comparison of relation between the flux at the top of atmosphere and that at the surface. The relation of UV-B is quadratic due to the strong ozone absorption in this band. Also, the dependence of the UV-B radiation on the stratospheric ozone depletion and stratospheric aerosol haze due to volcanic eruption on the stratospheric ozone depletion and stratospheric aerosol haze due to volcanic eruption has been tested with various solar zenith angles. The surface UV-B increases as the solar zenith angle increases. The existence of stratospheric aerosols causes an increase in the planetary albedo due to the aerosols' backscattering. The planetary albedo with aerosol's effect has been increases as the solar zenith angle is not sensitive. It may be caused by the fact that the aerosols' scattering effect becomes saturated with the relatively long path length in a large solar zenith angle. Finally, the regional impact of stratospheric aerosols due to volcanic eruption on the intensity of UV-B radiation at the surface has been estimated. A direct effect is that the flux is diminished at the low latitudes, while it is enhanced in the high latitudes by the aerosols' photon trap or twilight effect. In the high latitudes, both aerosols' scattering and ozone absorption have strong and opposite impacts to the surface UV-B radiation is located at the mid-latitudes during spring season in both hemispheres.

• Fire Science and Engineering
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• v.24 no.3
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• pp.39-44
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• 2010

The cone calorimeter method which is currently used to measure the heat release rate has a fixed rate of radiation. However, in the real fire, when flame combustible material burns, it releases the identical heat flux. We measured the changes of temperature of a fire using FDS in order to analyze flexible heat flux of combustion characteristics. In this study, the rate of radiation of cone calorimeter was adopted by using FDS. Follow those results, it produce between the rate of radiation in the growth period and decline period have a significant impact on heat release rate of PMMA.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.2
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• pp.331-344
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• 1987

A numerical analysis has been conducted on the interaction of the thermal radiation and natural convection in a rectangular enclosure filled with a gray fluid. P-1 approximation is adopted for the radiative transfer and its application limit is examined. Considered are the Stark number effect, the optical thickness effect and the wall emissivity effect on the flow and heat transfer characteristics. As the Stark number increase or the optical thickness decreases, the boundary layer thickness and the flow velocity increase. Transition to turbulence is retarded with the increase of the radiation effect. When the optical thickness is one, the radiation effect is negligible for the Stark numbers larger than 10.

• The Optical Journal
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• v.11 no.5 s.63
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• pp.14-19
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• 1999

외국에서 수입하거나 반입하는 물품에 대해 세관에서 징수하는 관세는 기업의 원가절감과 직결되고, 그만큼 정부의 지원이 필요하다. 그러나 현재 복사기, 카메라 생산 업체들은 산업현실과 맞지 않는 불합리한 관세제도로 국제시장에 경쟁력을 확보하는 데 많은 어려움을 겪고 있다. 복사기업체는 '부분품과 부속품'(HS/9009.90.0000)에 속하지 않더라도 모두 복사기 부품으로 인정해 동일한 관세율을 적용해 줄 것을 요구한다. 카메라 생산 업체는 각기 입장이 다

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.50-51
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• 2000

가속된 전자빔을 금속회절격자의 위로 통과시킬 때 결맞은 복사광(coherent radiation)이 발생하는데 이를 Smith- Purcell 효과라고 한다. 이때 발생하는 전자기파의 파장은 회절격자의 주기, 전자빔의 속도 및 복사광의 방출각도에 관계된다$^{(1)}$ . 그리고 방출된 복사광의 출력세기는 전자빔의 군집을 고려하지 않는 경우, 회절이론(diffraction theory)에 의해 얻을 수 있는데, 그 세기는 입사시킨 전자빔의 전류세기에 선형적으로 비례한다$^{(2)}$ . (중략)

• Korean Journal of Plant Taxonomy
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• v.36 no.3
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• pp.257-262
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• 2006

Prunus choreiana, invalidly published without Latin description in the original text, is validated here. The species has been known as a Korean endemic plant species of deciduous shrub, and a typical calciferous plant mainly distributed in Pyeongnam Province and Hamnam Province, North Korea. However, recently new population was reported from Mt. Myon and another new population is reported here from Mt. Jabyeong in Gangwon-do.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.5-5
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• 1998

수정된 연소 반응 함수를 이용하여 복사 열속 교란에 대한 연소 반응 특성을 살펴보았다. Catalyzed DB N5 추진제의 연소 반응을 살펴보기 위하여 Son 등의 실험 결과와 비교하였다. Son 등의 연소 반응 함수는 물리적으로 타당하지 않은 활성화 에너지에서 실험 결과를 예측하였지만, 수정된 연소 반응 함수는 비슷한 추진제의 실제 활성화 에너지 범위에서 복사 열속에 대한 연소율의 반응을 비교적 잘 예측할 수 있었다. 이것은 Son 등에 의해 과소 평가된 복사 열속(f, J)의 영향이 고려되었기 때문인 것으로 판단된다. 민감 변수(sensitivity parameter)들을 구하기 위하여 Ibiricu 등이 제시한 정상 연소 관계식을 이용하였다. AP계 추진제의 표면 온도에 대한 정상 연소율 변화를 살펴본 결과 Zanotti의 AP2 추진제의 실험 결과와 정성적으로 비슷한 경향을 나타내었다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1652-1660
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• 1990

Combined radiative-convective heat transfer in a hot gas tube flow has been investigated numerically and experimentally. In the numerical analysis, a standard k-.epsilon. model is used for the evaluation of turbulent shear stresses and spherical harmonics method with the Weighted Sum of Gray Gases Model for the solution of radiative transfer equation. In the experimental study measured are the velocity and temperature of the hot gas flow generated by the propane gas combustion, and tude wall heat flux distribution. Numerical results are compared with experimental ones and it is confirmed that P-3 provides quite reliable results in the analysis of the combined radiation-convection system.