• 환경위생공학
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• 제13권2호
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• pp.82-87
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• 1998

The opening temperature of emit heat, caloric value and decomposition hear were investigated by DSC & TGA in order to find the hazard of sanitary feed-stuff, also explosion hazard of dust was observed with electrical ignition after fodder dispersion by compressed air. Then opening temperature of emit heat of supporting gas. $O_{2}$ was much lower than inert gas. Ar. and caloric value increased 20. and the particle size of sanitary feed-stuff were appeared fire or explosion at 50/60 mesh and 60/80 mesh.

• 한국산업융합학회 논문집
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• 제5권2호
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• pp.119-126
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• 2002

In this study, general engine oil and the Miracle top engine oil of Dongjin chemistry company were tested to find the effects to the SI engine performance. Roller dynamometer used to find maximum power, fuel consumption rate and the emission. Maximum power was measured higher when the Miracle top engine oil was used in the vehicle. By use of the Miracle top engine oil, fuel consumption rate and emission was measured lower and compression pressure was higher compared use of general engine oil. Also the Miracle top engine oil was found to decrease the engine noise at the low RPM. And after 1,500km drive at the same condition, the dust in the oil pan and oil filter was measured less when the Miracle top engine oil used compared than general engine oil used.

• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.279-288
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• 2010

To study properties of the pulsation in the infrared emission for long period variables, we have collected and analyzed the infrared observational data at M band for 12 OH/IR stars. We present the light curves using the data that cover about 30 years including recent observations of ISO and Spitzer. We use Marquardt-Levenberg algorithm to determine the pulsation periods and amplitudes and compare them with previous results of infrared and radio investigations. Generally, the newly determined pulsation parameters show much less errors because of the larger database. We find that the relationship between the pulsation period and amplitudes at M band is fairly well fitted with a simple linear equation in a wide period range. For OH 42.3-0.1, we find some evidences that the object could be a post-asymptotic giant branch star.

• 천문학회보
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• 제44권1호
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• pp.70.4-70.4
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• 2019

Complex organic molecules (COMs) are increasingly observed in the environs of young stellar objects (YSOs), including hot cores/corinos around high-mass/low-mass protostars and protoplanetary disks. It is widely believed that COMs are first formed in the ice mantle of dust grains and subsequently released to the gas by thermal sublimation at high temperatures (T>100 K) in strong stellar radiation fields. In this paper, we report a new mechanism that can desorb COMs from icy grain mantles at low temperatures (T<100K), which is termed rotational desorption. The rotational desorption process of COMs comprises two stages: (1) ice mantles on suprathermally rotating grains spun-up by radiative torques (RATs) are first disrupted into small fragments by centrifugal stress, and (2) COMs and water ice then evaporate rapidly from the tiny fragments (i.e., radius a <1nm) due to thermal spikes or enhanced thermal sublimation due to increased grain temperature for larger fragments (a>1 nm). We discuss the implications of rotational desorption for releasing COMs and water ice in the inner region of protostellar envelopes (hot cores and corinos), photodissociation regions, and protoplanetary disks (PPDs). In shocked regions of stellar outflows, we find that nanoparticles can be spun-up to suprathermal rotation due to supersonic drift of neutral gas, such that centrifugal force can be sufficient to directly eject some molecules from the grain surface, provided that nanoparticles are made of strong material. Finally, we find that large aggregates (a~ 1-100 micron) exposed to strong stellar radiations can be disrupted into individual icy grains via RAdiative Torque Disruption (RATD) mechanism, which is followed by rotational desorption of ice mantles and evaporation of COMs. In the RATD picture, we expect some correlation between the enhancement of COMs and the depletion of large dust grains in not very dense regions of YSOs.

• 한국약용작물학회지
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• 제6권1호
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• pp.16-20
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• 1998

유기물(有機物) 시용(施用)에 따른 전호(前胡) 뿌리 의 조단백질(粗蛋白質), 조지방(粗脂肪), 조섬유(粗纖維), 조회분(粗灰分) 등(等) 성분(成分)과 정유성분(精油成分)의 변화(變化)에 대한 실험(實驗)을 통하여 얻어진 결과(結果)를 요약(要約)하면 다음과 같다. 1. 초장(草長)은 대조구(對照區)인 단비(單肥)보다 볏집 퇴비(堆肥), 활엽수(闊葉樹) 퇴비(堆肥) 및 산야초(山野草) 퇴비(堆肥)에서는 다소 짧은 경향(傾向)을 보였으나 계분(鷄糞)톱밥 퇴비(堆肥)에서 가장 길었고. 10a 당(當) 근수량(根收量)은 단비(單肥) 165kg보다 계분(鷄糞)톱밥 퇴비(堆肥)에서 276kg으로 가장 높았고 산야초퇴비(山野草堆肥) 193kg, 활엽수(闊葉樹) 퇴비(堆肥) 188kg이었으나 볏짚 퇴비(堆肥)는 148kg으로 가장 낮았다. 2. 계분(鷄糞)톱밥 퇴비(堆肥) 시용구(施用區)에서 조단백질(粗蛋白質) 7.36 %, 조지방(粗脂肪) 5.57%, 조섬유(粗纖維) 2.89%로 단비(單肥) 및 기타 퇴비시용구(堆肥施用區)보다 현저(顯著)히 높게 나타났다. 3. 식물(植物) 정유(精油) 함량(含量)은 계분(鷄糞)톱밥 퇴비(堆肥)에서 0.82%로 가장 높았다. 4. 향기(香氣) 성분(成分)의 조성(組成)은 특(特)히 sabinene과 carboxaldehyde의 2개(個) 성분(成分)이 단비(單肥)에서 각각(各各) 14.4, 120.3 % area였으나 계분(鷄糞)톱밥 퇴비(堆肥)에서는 16.9, 163.4% area로 높게 나타났다.

• 천문학논총
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• 제27권4호
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• pp.353-356
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• 2012

We present new constraints on the cosmic optical background (COB) obtained from an analysis of the Pioneer 10/11 Imaging Photopolarimeter (IPP) data. After careful examination of the data quality, the usable measurements free from the zodiacal light are integrated into sky maps at the blue (${\sim}0.44{\mu}m$) and red (${\sim}0.64{\mu}m$) bands. Accurate starlight subtraction was achieved by referring to all-sky star catalogs and a Galactic stellar population synthesis model down to 32.0 mag. We find that the residual light is separated into two components: one component shows a clear correlation with the thermal $100{\mu}m$ brightness, whilst the other shows a constant level in the lowest $100{\mu}m$ brightness region. The presence of the second component is significant after all the uncertainties and possible residual light in the Galaxy are taken into account, thus it most likely has an extragalactic origin (i.e., the COB). The derived COB brightness is ($(1.8{\pm}0.9){\times}10^{-9}$ and $(1.2{\pm}0.9){\times}10^{-9}\;erg\;s^{-1}\;cm^{-2}\;sr^{-1}\;{\AA}^{-1}$ in the blue and red spectral regions, respectively, or $7.9{\pm}4.0$ and $7.7{\pm}5.8\;nW\;m^{-2}\;sr^{-1}$. Based on a comparison with the integrated brightness of galaxies, we conclude that the bulk of the COB is comprised of normal galaxies which have already been resolved by the current deepest observations. There seems to be little room for contributions from other populations including "first stars" at these wavelengths. On the other hand, the first component of the IPP residual light represents the diffuse Galactic light (DGL)-scattered starlight by the interstellar dust. We derive the mean DGL-to-$100{\mu}m$ brightness ratios of $2.1{\times}10^{-3}$ and $4.6{\times}10^{-3}$ at the two bands, which are roughly consistent with previous observations toward denser dust regions. Extended red emission in the diffuse interstellar medium is also confirmed.

• 천문학회지
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• 제48권1호
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• pp.57-66
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• 2015

Monte-Carlo radiative models of the diffuse Galactic light (DGL) in our Galaxy are calculated using the dust radiative transfer code MoCafe, which is three-dimensional and takes full account of multiple scattering. The code is recently updated to use a fast voxel traversal algorithm, which has dramatically increased the computing speed. The radiative transfer models are calculated with the generally accepted dust scale-height of 0.1 kpc. The stellar scale-heights are assumed to be 0.1 or 0.35 kpc, appropriate for far-ultraviolet (FUV) and optical wavelengths, respectively. The face-on optical depth, measured perpendicular to the Galactic plane, is also varied from 0.2 to 0.6, suitable to the optical to FUV wavelengths, respectively. We find that the DGL at high Galactic latitudes is mostly due to backward or large-angle scattering of starlight originating from the local stars within a radial distance of r < 0.5 kpc from the Earth. On the other hand, the DGL measured in the Galactic plane is mostly due to stars at a distance range that corresponds to an optical depth of $${\sim_\sim}$$ 1 measured from the Earth. Therefore, the low-latitude DGL at the FUV wavelength band would be mostly caused by the stars located at a distance of $r{\leq}0.5$ kpc and the optical DGL near the Galactic plane mainly originates from stars within a distance range of $1{\leq}r{\leq}2kpc$. We also calculate the radiative transfer models in a clumpy two-phase medium. The clumpy two-phase models provide lower intensities at high Galactic latitudes compared to the uniform density models, because of the lower effective optical depth in clumpy media. However, no significant difference in the intensity at the Galactic plane is found.

• 한국화재소방학회논문지
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• 제24권5호
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• pp.68-78
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• 2010

본 연구의 목적은 소방공무원들이 현장 활동 중에 석면함유 비산먼지로 위협되고 있는 현상에 대한 심각성을 사례 및 설문을 통해 발생 원인을 찾아 현장 활동 중에 석면노출을 효과적으로 예방하는데 있다. 소방관들의 현장 활동과 석면분진의 위험성에 대한 상관관계를 설문조사를 하여 분석하고 석면으로 인해 발생하는 석면폐암, 악성중피종과 같은 질병으로부터 소방공무원을 보호하고, 불합리한 여건들을 변화시킴으로써 조직운영의 최적화와 안전하고 쾌적한 근무여건을 통하여 소방공무원들이 현장 활동에서 치명적인 위해요소를 사전에 제거 하거하고자 한다. 또한 석면노출 기준에 따른 보호 장비 착용으로 철저한 소방 활동을 강화함은 물론, 소방 활동상 유해성인자의 심각성을 인식하고, 질환 피해보상에 대한 법적 제도를 마련하여, 아직까지 인정되고 있지 않은 질병에 대한 공무상 재해인정을 통한 제도적 미비점을 보완하여, 소방공무원의 사기진작 및 근무여건개선으로 대 국민 서비스 향상 등을 기대하고자 한다.

• 천문학회보
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• 제39권1호
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• pp.61.1-61.1
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• 2014

GSH 006-15+7 is a Milky Way supershell discovered by Moss et al. (2012). This supershell shows large shell-like structures in H I velocity maps. We have analyzed FUV emission for the supershell regions based on the FIMS and GALEX observations. Bright FUV flux at the boundaries of the supershell is mostly originated from dust scattering of FUV photons by dust clouds which was also observed at the boundaries of the supershell. We could find the distance to the supershell can be closer more than 30% compared with the distance of 1500 pc suggested by Moss et al. (2012) from the dust scattering simulation. And we also found the albedo and the phase function asymmetry factor of interstellar grains were 0.30 and 0.40, respectively. The confidence range for the albedo covers the theoretical value of 0.40, but g-factor is rather smaller than the theoretical value of 0.65. The small g-factor might mean the environment of turbulent ISM of the supershell. Meanwhile, the excess of C IV and X-ray emissions in the inside of the supershell can support the existence of hot gas and cooling in the supershell. And the C IV and X-ray emissions are monotonically decrease as away from the center of the SNR. This indicates the size of the hot bubble has considerably shrunk. We applied a simple simulation model to the PDR candidate region of the lower part of the supershell and obtained a H2 column density N(H2) = 1017.0-18.0 cm-2 and total hydrogen density nH ${\geq}$ 10 cm-3. This result shows the PDR candidate region represents a transition region from the warm phase to the cool phase in the PDR.

• 대한건축학회논문집:계획계
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• 제34권7호
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• pp.21-29
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• 2018

This study aimed to find and suggest the purpose of future plans, critical items on designing and Related standards to amend construction standards for domestic energy saving and environmentally friendly housings. It would also activate and increase the supplies of passive house minimizing the problems on current apartment housings in winter and reducing heating energy which brings fine dust pollution. After defining the standard model of Korean apartment housings(reference model), this study calculated the amount of heating energy demand per unit area annually as applying the yearly changed standards from 2008 to 2017 to existing standard model. It turned out that applying 2017 construction standards of energy saving and eco-friendly housings to reference model has saved up to 75% of heating energy demand comparing to the one applied 2008's. However, it still could not solve the fundamental problems such as winter fungus, condensation, freezing, freeze and burst, and insulation weakness space, and could not be free from fine dust particles. To solve them, this study suggested improved standards adding critical items on design related to outside insulation, cut off the heat-bridge, enforce air-tightness and heat change efficiency on heat recovery ventilator. As a result, it has reduced more than 10% of heat demand from 2017. It would be more than 90% of savings from 2008 if we make the amount of heat loss be zero on heat bridge on designing stage in the future.