• 동력기계공학회지
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• 제18권6호
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• pp.180-185
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• 2014

Due to the larger and high-speed vessels recently constructed, output and speed of the engines for propulsion or power generation is increasing. These high-power and high-speed engine of the ship is becoming as a major contributor causing excessive noise and vibration. Other fittings as well as equipment installed on board, it makes equipment failure or other defect by resonance. This causes a lot of M/H(Man Hour) for repairs and the reliability of the company is invading even be negative because the clients give much comment. Thus, it's being studied for any fittings installed on board to maintain the safe operation and to prevent any problem during the performance in any operating conditions. In this study, it was investigated to solve these problems for the supports of the various fittings for easy installation-related support that each type of intensity and shape and manufacturing method using structural analysis program(DNV Nauticus Hull 3D Beam). Namely, it would be applied to the very large crude carriers in consideration of mechanics of materials of the support equipment by providing the fact that dynamics analysis of the structural characteristics of the equipment and the support of the production installation is easy and productivity can be high standards for geometry and thereby to simplify the analysis task to design changes at the same time and to minimize the reinforcement for the supports.

• 한국태양에너지학회 논문집
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• 제36권4호
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• pp.57-65
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• 2016

Domestic photovoltaic system for roof-top is installed towards the south at an angle of 20 to 35 degrees and the shape of PV array is divided into two kinds; a plane shape and a curved shape. This paper aims to understand an actual condition of PV facility and strengths and weaknesses of support structure production and installation and to consider the best PV surface shape by analyzing theoretical logics of these two surface shapes and architectural perspective-based realistic case studies. This study targeted 98 facilities including common houses, public institutions and education institutions. In common houses, all of 59 PV facilities have a plane surface. In public institutions, 7 of 15 PV facilities have a curved array surface and 8 PV facilities have a plane surface. In education institutions, also, 14 of 24 PV facilities have a plane array surface and 10 PV facilities have a curved surface. Most of 98 facilities have a flat roof supporting shape. However, it was found that the curved shape wasn't positive for PV generation due to the change of radial density and it was at least 10 % more expensive to produce its structure. Also, domestic general large single-plate PV facilities have problems of harmony with buildings and wind load. Therefore, it is considered that for fixed-type roof-top PV, a plane PV array shape is good for optimum generation and economic efficiency and a parallel array structure on the roof surface is favorable to wind load and snow load without being a hindrance to the building facade.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.196-202
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• 2008

Effective climate protection is a most important tasks of our time. The BIPV is one of the most interesting and promisingly possibilities of an active use of solar energy at the building. In this study it was analyzed by the case study the function of the requirement of the BIPV-module as building material and this architectural characteristic according to the kind of the module. Therefore the goal of this study is to get securing the application information of BIPV as windowpane. BIPV modules are manufactured in the form of G/G. In the case of the crystal type the Transparent and the light Transmission is to be adjusted by the spacer attitude of the cell. Although this type could not be optimal for light effect of indoors because of the inequality of shade, the moving shade play makes a dramatic Roomimage by the run of sun. The application of this type would be for canopy, window or roof in the corridor or resounds. With amorphous the type it is to be manufactured simply largely laminar, and thus that will shorten building process. There is a relatively good economy to use and to the window system easily. After the production technology is easy the transparency of the modules to adjust, and the module shows to a high degree constant characteristics of light permeability and transparency. Without mottle of module shade is good the use for the window or roof glazing of office, library, classroom, etc. to adapt. The BIPV modules took generally speaking a function as building material to the daylight use, shading, isolation and also to the sight. That means that BIPV modules have as multifunctional system to sustainable architecture good successes and they are at the same time as Design element for architecture effectively.

• 한국표면공학회지
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• 제40권4호
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• pp.190-196
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• 2007

Dye sensitized solar cells(DSSC) are the most promising future energy resource due to their high energy efficiency, low production cost, and simple manufacturing process. But one problem in DSSC is short life time compared to silicon solar cells. This problem occurred from photocatalytic degradation of dye material by nanometer sized $TiO_2$ particles. To prevent dye degradation as well as to increase its life time, the transparent coating film is needed for UV blocking. In this study, we synthesized nanometer sized $TiO_2$ particles in sols by increasing its internal pressure up to 200 bar in autoclave at $120^{\circ}C$ for 10 hrs. The synthesized $TiO_2$ sols were all formed with brookite phase and their particle size was several nm to 30 nm. Synthesized $TiO_2$ sols were coated on the backside of fluorine doped tin oxide(FTO) glass by ink jet printing method. With increasing coating thickness by repeated ink jet coating, the absorbance of UV region (under 400 nm) also increases reasonably. Decomposition test of titania powders dispersed in 0.1 mM amaranth solution covered with $TiO_2$ coating glass shows more stable dye properties under UV irradiation, compared to that with as-received FTO glass.

• 한국인터넷방송통신학회논문지
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• 제20권1호
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• pp.199-204
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• 2020

국내에서 사용 중인 실리콘 태양전지판의 경우 제작 사양이 -0.5에서 0.05℃ 한계에서 최대출력을 낼 수 있도록 설계되어있어 온도 1℃ 상승 시 0.45~0.55%의 출력이 감소한다. 결과적으로 태양광발전은 태양전지(CELL)의 특성상 태양광모듈의 표면 온도상승에 따라 출력이 떨어지게 된다. 출력 저하는 태양광발전의 효율을 떨어뜨리며 효율이 떨어지면 최종적으로 태양광발전의 발전량에 따른 전력판매 수익이 감소하는 결과를 낳는다. 따라서 본 논문에서는 온도검출 센서를 통해 설정된 온도 이상으로 식별 시 태양광모듈 하부(또는 주변)에 냉각 공기를 분사시키는 방식을 연구방안으로 제안한다. 추가로 손실된 태양에너지를 활용하여 발전량을 증가시키며 냉각 공기를 통한 냉각기능을 적용함으로써 발전량을 더욱 증대시킬 수 있도록 하였다.

• 청정기술
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• 제26권1호
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• pp.72-78
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• 2020

화석연료의 사용과 바이오가스 생산 과정에서 공기오염과 기후변화문제가 발생된다. 기후변화 주요 원인물질인 이산화탄소와 메탄을 양질의 에너지원으로 전환하는데 연구가 지속되고 있다. 본 연구에서는 바이오가스를 양질의 에너지로 전환하고 태양광과 풍력과 같은 연속생산의 문제가 있는 재생에너지와 연계된 태양연료를 생산하기 위해 플라즈마-탄화물 전환장치를 제안하였다. 그리고 이에 대한 가능성을 제시하기 위해 바이오가스 전환에 영향을 미치는 O₂/C비, 전체가스공급량, CO₂/CH₄공급비의 변화에 따른 전환 및 생성가스 특성 파악하였으며 그 결과는 다음과 같다. O₂/C비가 높아질수록 메탄과 이산화탄소의 전환이 증가하였다. 전체가스공급량은 임의 특정 값에서 최대의 전환을 보였다. CO₂/CH₄비 감소할 때 전환율이 증가되었다. 이상의 결과로 볼 때 본 연구에서 새로이 제안된 플라즈마 산화분해-탄화물 가스화 전환에 의한 태양연료 생산의 가능성이 확인되었다. 그리고 O₂/C비가 0.8이고 CO₂/CH₄를 0.67로 하여 전체가스공급량을 40 L min^-1 (VHSV = 1.37)로 공급할 경우 이산화탄소와 메탄 전환이 최대가 되어 생성가스 중 양질의 연료인 수소와 일산화탄소로의 전환이 최대를 보였다.

• The Korean Journal of Ecology
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• 제1권2호
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• pp.57-65
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• 1977

The biomass and net production of alder and oak trees was estimated by allometric method. The productivity of the two stands of alder and oak was obviously different judging from the rate of photosynthesis productive structure and vertical distribution of light. The amounts of net photosynthesis under the saturated light were 2.31, 1.42mg $CO_2/dm^2\cdot$hr. in the sun and shade leaves of alder tree and 1.58, 0.84mg $CO_2/dm^2\cdot$hr in that of the oak, respectively. Total annual respiration loss calculated from the respiration measured at $25^{\circ}C$ and the mean air temperature from every 10 days were 13.56ton/ha.yr in the alder stand and 19.83 ton/ha.yr in the oak. The productive structure and the vertical distribution of light in the stand were assumedly more effective to produce dry matter in the oak stand than in the alder. The biiomasses measured in 1975 and 1976 were 51.51 and 56.82 ton/ha in the alder stand and 73.35, 86.77 ton/ha in the oak one, respectively. Annual net production and gross production were 8.56 and 22.12 ton/ha.yr in the alder stand but those were 17.90 and 37.74 ton/ha.yr in the oak stand. The ratios of respiration to gross procution (R/Pg) were prespectively 0.61 and 0.53 inthe alder and oak stands. Efficiencies of solar energy utilizaztion of net production during the growing season(May-Oct.) were 0.67 and 1.40% and those of gross production were 1.72 and 2.94% in the alder and oak stands respectively.

• 한국초지조사료학회지
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• 제20권3호
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• pp.147-154
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• 2000

This study was conducted to increase the utility and productivity of forage crops at high altitued areas. For that purpose, 21 cultivars of corn and 2 cultivars of rye were cultivated for 3 years using a randomized block designed with 3 replications. The results obtained were as follows. 1. In the Taekwallyong area (800m above sea level) which has a short frostless period, all the seeding and harvest of corn must be finished within about 135 days between mid May, the time of the last frost, and late September, the time of the first frost 2. It was relatively safe for the early maturity cultivar(ll0days) and the medium maturity cultivar(l20days), compared to the late maturity cultivar(l30days) which might have had the possibility of an overlapping period between the time of harvest and the first frost in high altitude areas 3. The productivity of forage corn, which is the most efficient crop for capturing solar energy, varied significantly with the climate circumstances but the productivity of Taekwallyong showed similar results of 19 M/T/ha, compared with 20 M/T/ha in Suwon from the '96-'98 study 4. Rye could be cultivated in high altitude areas and when corn was raised as a second crop after rye in the same year, it was possible to increase the productivity of dry matter yield by 20% through double cropping(P < 0.05). (Key words : Cropping system, Corn, Rye, Forage production)

• 시스템엔지니어링학술지
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• 제15권1호
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• pp.25-33
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• 2019

In the plant industry, the share of equipment accounts for 45 ~ 75%, which is very high. It is a traditional plant centered on processes and reactions like petroleum and chemical plants. Renewable energy generation plants such as wind power generation and solar power generation are equipment-centric plants. Equipment-centric plants are very important not only in the EPC phase but also in the operation and management phase. The procurement of equipment for plant operation and management can be divided into make and buy. Make is a method of producing equipment itself, and buy is a method of procuring equipment from the outside. The procurement method of the equipment directly affects the plant operation and management cost. In this study, the decision making of equipment procurement method for plant operation and management is defined as 4 phase. Each phase is selection of procurement decision-making objects, technology strategy perspective, finance perspective, and production perspective. In detail, we defined selection process of procurement decision-making objects and technology strategy perspective process. We will contribute to the enhancement of the competitiveness of the plant operation and management area by carrying out researches on the process and application examples of financial and production perspectives in the future.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.94-97
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• 2005

For the fabrication of poly-crystalline silicon ingot, CCCC (Cold Crucible Continuous Casting) method under a high frequency alternating magnetic field, was utilized in order to prevent crucible consumption and ingot contamination and to increase production rate. In order to effectively and continuously melt and cast silicon, which has a high radiation heat loss due to the high melting temperature and a low induction heating efficiency due to a low electric conductivity, Joule and pinch effects were optimized. Throughout the present investigation, poly-crystalline Si ingot was successfully produced at the casting speed of above 1.5 mm/min under a non-contact condition.