• International journal of advanced smart convergence
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• 제10권2호
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• pp.15-20
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• 2021

We constructed an air-lifted seawater propulsion system for decreasing fuel consumption of the ships. The system has a form of pipes which can be easily installed on the sides of the ship. Seawater mixed with air, will rise along within the pipe, and will be discharged downward. If the directions of inlet / outlet of the pipe are designed properly, a propulsive energy can be obtained. We tested the system with a model ship in Jangsa port at Sokcho-city with a water depth of 2.5 meters. The system was supplied regulated air at 6 bars during the 3 tests. The model ship was moving forward at a rate of 0.18 meters per second. In case of large ships equipped zfrom clean energy.

• 한국환경과학회지
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• 제17권9호
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• pp.1053-1068
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• 2008

This study aims to produce fundamental database for Environment Impact Assessment by monitoring vertical structure of the atmosphere due to the mountain valley wind in spring season. For this, we observed surface and upper meteorological elements in Sangin-dong, Daegu using the rawinsonde and automatic weather system(AWS). In Sangin-dong, the weather condition was largely affected by mountains when compared to city center. The air temperature was low during the night time and day break, and similar to that of city center during the day time. Relative humidity also showed similar trend; high during the night time and day break and similar to that of city center during the day time. Solar radiation was higher than the city, and the daily maximum temperature was observed later than the city. The synoptic wind during the measurement period was west wind. But during the day time, the west wind was joined by the prevailing wind to become stronger than the night time. During the night time and daybreak, the impact of mountain wind lowered the overall temperature, showing strong geographical influence. The vertical structure of the atmosphere in Dalbi valley, Sangin-dong had a sharp change in air temperature, relative humidity, potential temperature and equivalent potential temperature when measured at the upper part of the mixing layer height. The mixing depth was formed at maximum 1896m above the ground, and in the night time, the inversion layer was formed by radiational cooling and cold mountain wind.

• 대한지구과학교육학회지
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• 제13권1호
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• pp.15-28
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• 2020

이 연구의 목적은 중학교 '태양계 단원에서 비유를 활용한 HTE(Here, There, Everywhere) STEAM 프로그램을 개발하고, 이 프로그램을 세종시 소재 A중학교와 평택시 소재 B중학교의 1학년 중학생 354명에게 적용하여 프로그램의 효과성을 검증하는 과정을 통해 지능정보사회를 대비한 창의교육을 실현하는데 있다. 개발한 STEAM 프로그램은 전문가 집단을 구성하여 3차례에 걸쳐 수정, 보완하여 타당성을 검증받았으며, 최종 개발된 프로그램은 총 6차시에 걸쳐 현장에 적용하였다. 이에 따른 효과성을 알아보기 위해 논리적 사고력 검사와 STEAM 관련 태도 검사를 프로그램 처치 전과 처치 후에 실시하였으며, 프로그램에 대한 학생들의 인식을 알아보기 위해 프로그램 처치 후 STEAM 만족도 검사를 실시하였다. 이 연구의 결과는 다음과 같다. 첫째, 비유를 활용한 STEAM 프로그램이 중학생의 논리적 사고력 향상에 효과적인 것으로 나타났다. 둘째, 비유를 활용한 STEAM 프로그램이 중학생의 STEAM 태도 향상에 효과적이었다. 셋째, 비유를 활용한 STEAM 프로그램에 대한 중학생의 인식이 긍정적이며, 과학에 대한 흥미를 일으키는데 효과적이었다. 이러한 결과를 통해 차기 수업에서는 충분한 시간을 통해 STEAM 프로그램 수업을 수행한다면 중학생들의 수업에 대한 만족도가 더욱 높아질 것으로 사료된다.

• 한국태양에너지학회 논문집
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• 제32권6호
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• pp.134-140
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• 2012

With rapid modernization and industrialization, many urban areas are becoming overcrowded at a rapid pace and such urban ecological problems as heat island effect are becoming serious due to the reduced green zones resulted from the indiscriminate development. To solve this problem, ecological park, constructed wetlands, and greening on the elevation, balcony, and roof of a building that have the structure and function very close to the state of nature are currently being promoted at the urban or regional level. Especially green roof will be able to not only provide the center of a city with a significant portion of green area but also help to relive heat island effect and improve micro climate by preventing concrete of a building from absorbing heat. According to a recent study, the temperature of green roof in the summer season shows a lower temperature than the outdoor temperature, but inversely the concrete surface shows a higher temperature. Accordingly, this study measured the surface temperature of buildings with green roof in Daejeon area in order to determine how the green roof system would have an impact on the distribution of surface temperature and did a comparative analysis of the distribution of the surface temperature of green roof vs non-green roof based on these theoretical considerations. As a result, it was found that the surface temperature of green roof was lower by $4{\sim}7^{\circ}C$ than that of non-green roof. This is expected to contribute to the mitigation of urban heat island effects.

• 무역상무연구
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• 제55권
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• pp.265-290
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• 2012

CEPA (Comprehensive Economic Partnership Agreement) between India and Korea may vitalize Korean economy more and more. Currently most of Korean firms have entered into manufacturing industries like electronics and automobiles. But only a few Korean companies are trying to penetrate into Indian green industry so this paper suggest how to enter into Indian green industry, especially renewable energy sectors. First, Exporting main shaft, tower-flange and polysilicon products can be considered, as a first step of entry mode. Second, entry mode based on contract like technology licensing, strategic alliance and joint venture establishment can be also one of options. For example, Korean solar energy industry which show more competitiveness than that of Indians should try to make technological licensing on PV modules. In addition to this, they should also try to make joint ventures with right Indian partners and build up 'Solar City' nearby regions like Gurgaon in India where many Korean firms are located. Korean shipbuilding firms like Hyundai Engineering which keep on developing wind turbo engines can also try to make strategic alliance with Indian firms like Suzlon which has strong competitiveness. After that, they should explore Korean and Indian wind sector markets together. Third, brownfield investment can be last and final option as a entry mode as we consider the peculiar characteristics of renewable energy industry. Lastly, Korean government which are rush to indulge into green business should formulate more proper and realistic policies to give big incentives the concerned firms which are trying to open international green market so government should make Korean green firms not to lose good market opportunities related to green industry like renewable energy sectors. Renewable energy sectors are basically regarded as infrastructures so close contact to Indian central government as well as state government will be also required.

• 한국가스학회지
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• 제22권4호
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• pp.55-62
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• 2018

지구온난화로 인하여 태양광 발전에 대한 관심이 커지고 있다. 이에 따라 태양전지를 만드는 핵심물질인 폴리실리콘의 수요도 나날이 증가하고 있으며 시장이 커짐에 따라 생산공정에서 크고 작은 사고들이 발생하고 있다. 그 예로 2013년 상주시의 폴리실리콘 제조공장에서 염산이 누출되었고 2014년에는 여수시의 폴리실리콘 제조공장에서 화재가 발생하였으며, 2015년에는 군산시의 폴리실리콘 제조공장에서 STC(Silicon Tetrachloride)가 누출되었다. 이러한 누출 사고들은 사업장 내부에만 영향을 주는 것이 아니라 인근지역까지 영향을 줄 수 있다는 것이 특징이다. 따라서 본 연구에서는 폴리실리콘 제조공정에서 사용되는 위험물질을 파악하고, 최악의 누출 시나리오를 적용했을 때 누출량과 피해범위를 정량적으로 예측하였다. 그 결과 폭발에 따른 피해거리는 726 m로 예측되었고, 독성에 대한 피해거리는 4,500 m로 예측되었다. 그리고 TCS(Trichlorosilane), STC(Silicon Tetrachloride), DCS(Dichlorosilane)가 누출되어 공기 중의 수분과 반응하여 HCl이 생성될 경우 피해거리는 최대 5.7 km까지로 예측되었다.

• 한국태양에너지학회 논문집
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• 제32권5호
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• pp.83-93
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• 2012

This study is to perform the effect of urbanization in urban and suburban districts, and to identify regional characters of climate according to the analysis of slope at rise, and descent of temperature and globe temperature, correlation between seasonal temperature analysis, and calculation of degree hour. According to this study, the result is summarized as follows. (1) The average temperature, rated from high to low, consists of residential area, Daegu weather station, intracity, green belt, water-front green belt, and suburban. (2) At the rise and descent of temperature, the result of the slope change of in each point may be one of the useful indexes to be able to perform the regional unique thermal characteristic, including the seasonal urbanization. (3) Although there is a difference between the surface of the earth and ambient environment. The result of the correlation of temperature between summer and winter is that temperature slope in urban districts was higher than in suburban districts, and the difference of slope was unvaried among the four observations in the same city region. (4) To show objectively, regional thermal characteristics in urban and suburban districts, the exponentiation of winter degree hour and summer degree hours were checked. The result of the exponentiation is that the more artificial a region, the lower index.

• 천문학회보
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• 제42권2호
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• pp.50.2-50.2
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• 2017

Spatial distribution of atmosphereless bodies in the solar system provides an important clue as to their origins, namely asteroids from Mainbelt or comets from outer solar system. It is, however, difficult to distinguish asteroids and dormant comets due to their similar appearances. In this study, we conducted a unique observation to differentiate asteroids and dormant comets in terms of 'polarimetry'. We observed (331471) 1984 QY1 (hereafter QY1) at large phase angles using the Multi-Spectral Imager (MSI) on the 1.6-m Pirka Telescope from UT 2016 May 25 to June 24. QY1 is a dormant comet candidate in terms of the dynamical properties (i.e. the Tisserand parameter with respect to Jupiter, TJ = 2.68). We analyzed the polarization degree of QY1 as a function of phase angle and found its maximum polarization degree, $Pmax=8.68{\pm}0.28%$ and $8.72{\pm}0.38%$, in RC-and V-band, respectively, around the phase angle of ${\alpha}=100^{\circ}$. In addition, we obtained the geometric albedo, $pV=0.16{\pm}0.02$ by means of an empirical slope-albedo law. The polarimetric properties and the albedo value we acquired are similar to those of S-type asteroids rather than cometary nuclei. In this presentation, we introduce our observation and findings. In addition, we further discuss a dynamical transportation process from Mainbelt to the current orbit.

• 한국태양에너지학회 논문집
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• 제29권5호
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• pp.88-97
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• 2009

In these days, it attracts our attention to create a green outdoor environment around the building block in urban area. Green space and permeable ground covering are increased by laws and regulations. According to these trends, variety researches for improving outdoor environment are accomplished at this moment. However, the problems for outdoor environment such as heat island effect and air contaminant in urban area are still reported. The purpose of this study is to examine the variables to affect the formation of outdoor thermal environment by quantitative analysis. As a initial study, in this paper, the effect of ground composition on changes of surface temperature and heat flux in multi-residential building were analyzed by field measurement and numerical simulation. Through field measurement, the surface temperature and heat flux of artificial ground in multi-residential building in Suwon city were measured. The result showed that the surface temperature was decreased by about $20^{\circ}C$ with afforestation of artificial ground compared with those of concrete covering. Moreover, the inner temperature of artificial ground was changed as same behaviors of outdoor temperature changes to depths of 20cm. In simulation, the effect of soil types and depth of artificial ground on the changes of the surface temperature and heat flux were analyzed. As results, the natural soil ground was more effective against lowering the surface temperature than any other cases in the analyzed cases.

• 한국태양에너지학회 논문집
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• 제37권6호
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• pp.103-114
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• 2017

Radiation energy budget was analyzed using observation data from the Weather Information Service Engine (WISE) energy flux tower on the Seoul metropolitan area. Among observation data from the 13 energy flux towers, we used meteorological variables, radiation data (upward and downward short wave, upward and downward long wave, net short wave, net long wave and net radiation), albedo and emissivity for 15 months from July 2016 to September 2017. Although Gajwa (205) and Ttuksumm (216) sites located in urban, the albedo was relatively high due to the surround environment by glass wall buildings and the Han river around the sites. And Bucheon (209) site located in the suburb represented generally low emissivity. As a result, the albedo decreased and the emissivity increased in the city center. In the Seoul metropolitan area, the net radiation energy is $73.9W/m^2$ that the radiation budget of the surface is absorbed into the atmosphere. According to WISE observation data, it can be seen that observation at each sites are influenced by the surrounding environment.