• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.19-20
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• 2006

The emission of particulate matter from marine diesel engines is already restricted by regional regulations in some countries, and IMO has been preparing the regulation for particulate matter from 53rd MEPC. But confusingly, the gravimetric PM measurement methods and procedures are not established clearly yet. On the other hand, smoke measurement method is set clearly, and it can also indicate PM, though it is not direct gravimetric method. As the preparing step for regulations about PM, we measured the smote density of exhaust emission from the marine four-stroke diesel engines operated in constant speed and various load steps on the test-bed, using the filter-type smoke measuring instrument. As a result, we understood the omission characteristics of smoke from the engines. Additionally, to obtain the objective reliability of our measurement data, we carried out experimental studies about various measuring parameters that could affect the smoke density.

• 조명전기설비학회논문지
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• 제28권8호
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• pp.106-112
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• 2014

This paper presents the analysis of connected operation of photo voltaic source and Li energy storage system. The micro-grid has been installed and operated for several years at the campus of USF and has been a role of test bed. Photo voltaic source has been strongly influenced by the location, weather and climate of a installed area and Li battery is connected directly to the photo voltaic source to compensate for the limitations. The Li battery is operated to supply power output to the grid by the charging or discharging mode based on the average power output of the PV source which is calculated from monitored data for several years. The load of the PV and Li battery system is operated as a severe loading condition and the operating characteristics of PV source and Li battery are analyzed in detail. In connected operations of PV and Li battery to power system, the PV and Li battery is operated to supply constant power during only day time or peak time to increase load shedding ratio and efficient usage of generation sources in power system.

• 물과 미래
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• 제9권1호
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• pp.86-100
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• 1976

To study influences on the downstream, and the Gunsan harbor by setting up estuary of the Gumgang, available data which were collected from the measuring stations which were established within the river basin of which results attained are as follows: 1. The discharge can be calculated as the relationship between the discharge and precipitation in the basin is $R=4{\times}10^{-4}p^2$ or R=P-600 2. The discharge flow in to small resevoirs in the basin can be estimated as $QR=QS\frac{PR-600}{PS-600}(\frac{AR}{AS})$ 3. This daily average discharge at Kongju is 31% less than the during maximum probable discharge and that in Okcheon is 48% less than the daily maximum probable flood. 4. The maximum probable flood from the small stream in the basin can be estimated by a $Q=82.45A^{0{\cdot}464}$ 5. Sediments can be computed with Qs (suspended load)=1.41 $Q^{1{\cdot}42}$ and Qb (bed load)=165.2 $Q^{0{\cdot}705}$. 6. By setting up the specific estuary the tidal movement will be reduced to 93.6% on the average and the sedimentation is reduced to 96.0%. Upon review of overall analysis, the dead wate level of estuary of Gumgang will completely sedimented in next 30 years, therefore, the dredging work at Gunsan harbor is reduced to 73.6%, it is considered that life length will be extended about 52years taking account the existing condition.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.34-39
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• 2002

A Semi-Autonomous Underwater Vehicle (SAUV) capable of simple work at sea bed is under development in KRISO-KORDI. A pressure vessel of SAUV which is composed of FRP was manufactured to load electronic equipments. The objective of this paper is to verify the safety of the pressure vessel through conducting the structural analysis and test in pressure tank. Strain and stress under unit load were obtained by using ANSYS in the linear structural analysis. And local buckling analysis was performed with NASTRAN for the middle cylindrical hull. For the pressure test, strains were measured at three point. We found that the results by linear structural analysis and experiment are coincide well at the points where buckling does not occur. Maximum depth was estimated to be 250m by the local buckling analysis.

• 전기학회논문지
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• 제64권12호
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• pp.1666-1672
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• 2015

Small islands are quite adequate places where microgrid system with renewable sources can replace diesel engines as operation costs of diesel engine in most small islands are very high. To get the large amount of renewable energy, the microgrid system has very large capacity of renewable sources. The system with large capacity of renewable sources can meet the case when supplied energy is greater than the load and the fluctuation of source output is very large. The battery energy storage system can be a solution to stabilize the system with large capacity of renewable sources. In this case, BESS can be utilized as a master source for the synchronous operation of all sources including diesel engine, wind turbine and PV. The diesel generators can be used as a backup in case the BESS SOC goes below a certain level. In this paper, we suggest a novel unit commitment of diesel generators and operation schedule of pump for water supply service with the information of wind forecast, PV forecast, and load forecast. The proposed methods has been implemented and tested at the test bed in Gasa-Island.

• 한국추진공학회지
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• 제22권5호
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• pp.81-87
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• 2018

극초음속 비행체에서는 공기와의 마찰열과 엔진열의 증가로 기체 내부의 열적 부하가 발생한다. 이는 비행체 내부 구조물의 변형을 일으키고 오작동을 발생시킬 수 있다. 흡열연료는 액체 탄화수소 연료로써 흡열반응을 통해 열을 흡수할 수 있는 연료이다. 본 연구에서는 실제 반응조건과 비슷한 고정층 흐름형 반응기에서 Exo-tetrahydrodicyclopentadiene(exo-THDCP)를 연료로 사용하여 흡열 촉매 종류에 따른 흡열 반응 시 생성물, 코크 생성량과 촉매 특성 변화 간 관계에 대한 연구를 수행하였다.

• 한국폐기물자원순환학회지
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• 제35권7호
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• pp.640-646
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• 2018

Biomass-fired power plants produce electricity and heat by burning biomass in a boiler. However, one of the most serious problems faced by these plants is severe corrosion. In biomass boilers, corrosion comes from burnt fuels containing alkali, chlorine, and other corrosive substances, causing boiler tube failures, leakages, and shorter lifetimes. To mitigate the problem, various approaches implying the use of additives have been proposed; for example, ammonium sulfate is added to convert the alkali chlorides (mainly KCl) into the less corrosive alkali sulfates. Among these approaches, the high temperature corrosion prevention technology based on ammonium sulfate has few power plants being applied to domestic power plants. This study presents the results obtained during the co-combustion of wood chips and waste in a circulating fluidized bed boiler. The aim was to investigate the characteristics of pollution load in domestic biomass power plants with ammonium sulfate injection. By injecting the ammonium sulfate, the KCl content decreased from 68.9 to 5 ppm and the NOx were reduced by 18.5 ppm, but $SO_2$ and HCl were increased by 93.3 and 68 ppm, respectively.

• 농업과학연구
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• 제38권1호
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• pp.101-108
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• 2011

In forest work, working conditions are very hard to improve. The proper distribution of work time and good posture is believed to bring about direct improvements such as accident prevention. On this, this study has analyzed forest workers' posture and their working hours in order to improve their working conditions in stone channel work. Authors has chosen several core elements of stone channel work to focus on, which include stone masonry, excavation of bed, moving stone, directing work, choosing stone, and breaking stone. The ratio of real working time over total working time was shown as 84.6%. As for the time ratio of each elemental work over the real working time, the stone masonry was 60.4%, the directing work was 15.1%, moving stone was 12.1%, choosing stone was 7.1%, breaking stone was 3.3%, and excavation of bed was 2.0%. According to the analytical results provided by OWAS, the ratio of category III (Work posture has a distinctly harmful effect on the musculoskeletal system) has shown that moving stone turned out 65.2%, choosing stone was 61.5%, stone masonry was 46.1%, breaking stone was 14.3%, excavation of bed was 12.5% and directing work was 6.8%. Furthermore, the ratio of category IV (Work posture with an extremely harmful effect on the musculoskeletal system) has shown that excavation of bed turned out 37.5%, breaking stone was 28.6%, stone masonry was 27.3%, choosing stone was 7.7%, moving stone was 6.1% and directing working was 4.5%. These results are expected to be utilized for the improvement with respect to both working methods in the stone channel work and the workers' working posture.

• 한국지역지리학회지
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• 제16권2호
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• pp.100-109
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• 2010

미국 메사추세츠주 보스턴시의 네폰셋 강의 서로 다른 토지이용지역을 사례지역으로 선정하여, 강의 밑짐으로 토지이용의 차이를 분석할 수 있는지 실험하였다. 네폰셋 강은 거주지역, 산업지역, 농업과 삼림지역 등으로 토지이용이 구분되는데, 토질의 화학적 특성이 가장 차이가 나는 거주지역과 삼림지역 두 곳을 찾아 매닝의 'n'값과 HEC-RAS 모델의 결과치를 비교하여 두 지역의 차이를 분석하였다. HEC-RAS는 US Army Corp에서 개발한 모델로 강의 윤곽 및 흐름, 진행 및 경사 등을 면밀하게 분석할 수 있다. 거주지역 분석 결과는 매닝의 계수와 HEC-RAS 결과치가 매우 다르게 나타나는데, 이는 인공적으로 설치된 강 하류의 댐과 일반적이지 않은 경사에 기인한다고 판단되었다. 일반적인 경사를 지닌 댐상류에는 임계수위가 나타나는데, 매닝의 'n' 계수가 서로 다른 깊이를 반영해주고 있다. 댐은 강의 분리와 유속에 많은 영향을 미치고 있고, 상류 수위는 증가하는 대신 유속은 감소하게 된다. HEC-RAS 모델은 강의 구조와 형태 및 행태 등을 분석하는데 좋은 기법으로, 현재 많은 연구의 대상이 되고 있는 도시 내 강의 관리와 지역개발에 지리학적으로도 크게 활용할 수 있을 것이라 예상된다.

• 자원환경지질
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• 제37권2호
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• pp.153-171
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• 2004

하상퇴적물은 기반암의 풍화에 의해 가장 직접적인 영향을 받기에 본 연구에서는 한강 상류인 남한강유역과 북한강 유역의 하상 퇴적물을 대상으로 지화학적 분석자료를 통해 인근육상암석과의 상관관계와 근원암에 관하여 유추하였다. 지화학적 분석을 통해 연구지역 하상퇴적물들의 주성분원소, 미량성분원소, 회토류원소 등의 분석자룔르 비교한 결과 다음과 같은 경향성을 나타내었다. 본 연구지역 주성분 원소들의 분산 경향성은 남한강 하상퇴적물의 경우 산성 화성암의 일반적인 경향은 나타내었고, 북한강 하상퇴적물 역시 산성 화성암의 일반적인 경향을 나타냈다. 두 지역의 주성분 원소 분산 경향성은 서로 유사한 분산경향을 나타냈으며, 미량 성분 원소의 함량치 역시 두 지역에서 거의 유사하게 나타났다. 희토류원소의 REE pattern은 두 지역 모두 Eu에서의 부의 이상이 뚜렷하게 나타내며 산성 화성암 기원의 희토류원소 pattern과 전체적으로 유사한 경향을 나타냈다. 희토류원소의 함량에 있어서는 남한강 하상퇴적물에 비해 북한강 하상퇴적물의 함량이 훨씬 높게 나타났다. 중광물은 남한강 하상퇴적물의 경우 주로 투각섬석-양기석, 적철석, 석류석 군, 녹염석, 금홍석, 스핀 등이 관찰된다. 이는 두 지역의 인근 유역 육상지질이 대체로 변성암류와 화성암류가 주를 이루는 점과 조화적이다. 따라서 본 연구지역인 남한강과 북한강의 하상퇴적물은 대부분 화성암 기원 또는 변성암 기원의 성분으로 구성되며 퇴적암 기원의 성분은 거의 전부 뜬짐 또는 녹음짐으로 제거된 것으로 본다.