• 한국산학기술학회논문지
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• 제13권6호
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• pp.2702-2706
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• 2012

식물공장에서는 대부분의 시스템이 자동화되어 있지만 식물의 성장 상태는 인력에 의해 수동적으로 확인해야 하는 실정이다. 이에 본 논문에서는 두 대의 카메라를 이용하여 식물의 발육상태를 측정하는 방법에 대해 연구하였다. 식물측정 알고리즘을 이용하면 카메라와 간단한 시스템만으로 저렴하면서 신뢰할 만한 데이터를 얻을 수 있는 시스템을 구축할 수 있다. 따라서 본 논문에서는 식물 공장 내에서 생장하는 식물의 크기을 효율적으로 측정할 수 있는 모니터링 시스템을 개발하였다. 이 시스템을 활용함으로써 식물의 크기 측정 데이터를 유지 및 관리하는데 소요되는 시간을 절약하고 그에 따른 경비를 절감할 수 있으며, 식물공장 관리자의 작업효율을 향상시키는 효과를 얻을 수 있었고, 실제 시스템을 구축하여 제안한 시스템의 성능을 확인하였다.

• 한국환경과학회지
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• 제12권2호
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• pp.125-132
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• 2003

This study was executed by China along with the Tumen river, which formed border of North Korea and China. As a result 91 family, 282 genera, 363 species, 57 variety 4 species, total 424 taxa of vascular plants were identified. The examination area was include the region that had various vegetation such as upper swampy land, seashore dune, a river, a high mountain grassy plain, deciduous tree zone, evergreen coniferous forest zone. The followings are representative plants, which found in an examination area but not in South Korea. Picea koraiensis, Larix gmelini var. principis-ruprechtii, Betula playphylla, Ulmus pumila, Populus koreana, Ledum palustre var. diversipilosum, Rhododendron parvifolium, Salix brachypoda, Phacelurus latifolius, Carex gotoi, Carex capricornis, Calla palustris, Aquilegia flabellata var. pumila, Lilium davuricum, Astragalus membranaceus, Trifolium lupinaster, Ledebourieila seselodeds, Polemonium racemosum, Scutellaria baicalensis, Linnaea borealis, Thladiantha dubia, Inula helenium, Trollius hondoensis, Hypocaeris ciliata, Aconitum kirinense, Aconitum arcuatum, Potentilla viscosa var. macrophylla. And there are 21 rare and endangered species, which Korean Forest Sevice designated, such as Aconitum koreanum, Acorus calamus var. angustatus, Polygonatum stenophyllum, Drosera rotundifolia, Iris setosa, Jeffersonia dubia, Lilium davuricum, Lilium cernum, Paeonia obovata, Penthorum chinense, Phacelurus latifolius, Rosa marretii, Sparganium stoloniferum, Thymus quinquecostatus, Trillium tschonoskii, Utricularia japonica, Tripterospermum japonicum, Vaccinium uliginosum, Vaccinium vitis-idaea, etc. Especially, plants like, Acanthopanax senticosus, Jeffersonia dubia and Lillum cernum which have high values of ornamental, and medical use are in an extinction crisis. High swampy land was formed to upper stream of Tumen river. It showed representative vegitation, like Carex sp., Scirpus radirans, Eriophorum latifolium. Wetlands plant and a dune plant were mixed in down stream area of Tumen river. On a dune, seashore plants, such as Carex kobomugi, Salsola collina, Raphanus sativus var. raphanistroides, Rosa rugosa, Scutellaria strigillosa, Linaria japonica, Phacelurus latifolius were appeared frequently.

• Asian Journal of Atmospheric Environment
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• 제2권2호
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• pp.102-108
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• 2008

In China, energy and environmental problems are becoming serious owing to rapid economic development. Coal is the most problematic energy source because it causes indoor and outdoor air pollution, acid rain, and global warming. One type of clean coal technology that has been developed is the coal-biomass briquette (or bio-briquette, BB) technique. BBs, which are produced from pulverized coal, biomass (typically, agricultural waste), and a sulfur fixation agent (slaked lime, $Ca(OH)_2$) under high pressure without any binder, have a high sulfur-fixation effect. In addition, BB combustion ash, that is, the waste material, can be used as a neutralization agent for acidic soil because of its high alkalinity, which originates from the added slaked lime. In this study, we evaluated the suitability of alternative biomass sources, namely, aquatic plants, as a BB constituent from the perspective of their use as a source of energy. We selected three types of aquatic plants for use in BB preparation and compared the fuel, handling, and environmental characteristics of the new BBs with those of conventional BBs. Our results showed that air-dried aquatic plants had a higher calorific value, which was in proportion to their carbon content, than agricultural waste biomass; the compressive strength of the new BBs, which depends on the lignin content of the biomass, was high enough to bear long-range intracontinental transport in China; and the new BBs had the same emission control capacity as the conventional BBs.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1990년도 추계학술대회논문집; 한양대학교, 서울; 24 Nov. 1990
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• pp.113-124
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• 1990

Tap lines are small branch piping generally less than two inches in diameter. They typically branch off of header piping having a much larger diameter. An example of a common tap line is a 3/4 inch size high point vent or low point drain. Most tap lines have at least one valve near the header tap connection to provide isolation. Two valves are often required for double isolation. A light water reactor(LWR) nuclear power plant will have several hundred tap lines. These lines come in many sizes and shapes and serve numerous functions. A single process piping valve may have three different tap lines associated with it (figure 1). Table 1 delineates the different categories of tap lines. Vibration failures of tap lines are a common occurrence in all industrial plants including nuclear and fossil power plants. These types of failures constitute a significant percentage of all piping related failures. An unscheduled plant shutdown or outage resulting from the failure of a tap line decreases plant reliability and may have a detrimental effect on plant safety. Most tap line vibration failures can be avoided through the use of appropriate routing and support techniques. Standardized designs can be developed for use in a myriad of applications. These designs will not only minimize failures but will also reduce the necessary analysis and installation efforts.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.92-102
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• 2017

The analysis of steam generators as an interface between primary and secondary circuits in light water nuclear power plants is crucial in terms of safety and design issues. VVER-1000 nuclear power plants use horizontal steam generators which demand a detailed thermal hydraulics investigation in order to predict their behavior during normal and transient operational conditions. Two phase flow field simulation on adjacent tube bundles is important in obtaining logical numerical results. However, the complexity of the tube bundles, due to geometry and arrangement, makes it complicated. Employment of porous media is suggested to simplify numerical modeling. This study presents the use of porous media to simulate the tube bundles within a general-purpose computational fluid dynamics code. Solved governing equations are generalized phase continuity, momentum, and energy equations. Boundary conditions, as one of the main challenges in this numerical analysis, are optimized. The model has been verified and tuned by simple two-dimensional geometry. It is shown that the obtained vapor volume fraction near the cold and hot collectors predict the experimental results more accurately than in previous studies.

• KEPCO Journal on Electric Power and Energy
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• 제2권3호
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• pp.415-419
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• 2016

As the need for clean coal technology has grown, so has the global research and development efforts into integrated gasification combined cycle (IGCC) plants. An IGCC plant couples a gas turbine to a gasification block. Various technical and economic problems exist in designing such a system. One such problem is the difficulty in realizing economies of scale because the single-train flow capacity of commercial IGCC synthetic gas turbine plants is limited; the capacity does not exceed a net power rating of 300 MW. To address this problem, this study modeled and simulated a synthetic gas turbine with the goal of evaluating the feasibility of a 500 MW or larger IGCC plant. First, a gas turbine with the best output and efficiency was chosen for use with natural gas. The turbine was modeled using GateCycle (a simulation tool), and the integrity of the model validated by comparing the result to the design value. Next, off-design modeling was carried out for a gas turbine with synthetic gas based on its on-design model, and the result was compared with the study result of the gas turbine manufacturer. The simulation confirmed that it is possible to create a large capacity IGCC plant by undertaking the remodeling of a gas turbine designed to use natural gas into one suitable for synthetic gas.

• 환경생물
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• 제34권4호
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• pp.272-280
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• 2016

Changes in land use and increase in urban energy consumption influence urban life. This study analyzed the characteristics and patterns of urban heat and presents management schemes to generate a comfortable and sustainable urban environment. The study aimed to demonstrate the positive effects of artificial ground greening on improving the microclimate through evapotranspiration using perennial herbs. We have designed a chamber that could control constant temperature and humidity, measure temperature reductions in each plant and changes in sensible heat and latent heat. This study identified Sedum kamtschaticum as the most effective plant in controlling temperature. At $22^{\circ}C$, $3.2^{\circ}C$ temperature reduction was observed, whereas four other plants showed a $1.5^{\circ}C$ reduction. At $25^{\circ}C$, $2.0^{\circ}C$ temperature reduction was observed. On the other hand, the use of Sedum sarmentosum resulted in the lowest effect. Zoysia japonica is the most commonly used ground covering plant, although the temperature reduction of Lysimachia nummularia was more effective at high temperature conditions. Sensible heat and latent heat were calculated to evaluate the thermal performance of energy. At a temperature >$30^{\circ}C$, L. nummularia and S. sarmentosum emitted high latent heat. In this study, we analyzed the thermal performance of green roof perennial plants; in particular, we analyzed the evapotranspiration and temperature reduction of each plant. Since the substrate depth and types, plant species, and seasonal change may influence temperature reduction and latent heat of green roofs, further studies are necessary.

• Nuclear Engineering and Technology
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• 제49권5호
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• pp.989-995
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• 2017

Distributed Control System (DCS) communication networks, which use Fast Ethernet with redundant networks for the transmission of information, have been installed in digitalized nuclear power plants. Normally, failover tests are performed to verify the reliability of redundant networks during design and manufacturing phases; however, systematic integrity tests of DCS networks cannot be fully performed during these phases because all relevant equipment is not installed completely during these two phases. In additions, practical verification tests are insufficient, and there is a need to test the actual failover function of DCS redundant networks in the target environment. The purpose of this study is to verify that the failover functions works correctly in certain abnormal conditions during installation and commissioning phase and identify the influence of network failover on the entire DCS. To quantify the effects of network failover in the DCS, the packets (Protocol Data Units) must be collected and resource usage of the system has to be monitored and analyzed. This study introduces the use of a new methodology for verification of DCS network failover during the installation and commissioning phases. This study is expected to provide insight into verification methodology and the failover effects from DCS redundant networks. It also provides test results of network performance from DCS network failover in digitalized domestic nuclear power plants (NPPs).

• 식물병연구
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• 제24권4호
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• pp.257-264
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• 2018

딸기 수경재배시스템은 국내에서 매년 증가추세에 있다. 대부분의 딸기농가는 수경재배에서 베드를 멀칭하여 9월 초순 딸기묘를 정식한다. Fusarium oxysporum f. sp. fragariae에 의한 시들음병과 점박이응애 Tetranychus urticae는 정식 후 높은 온도조건에서 발생이 증가하는 경향이 있다. 따라서 베드 녹색 polyethylene(PE)필름 멀칭과 무멀칭처리에서 시들음병과 점박이응애 발생을 비교하기 위해 시험을 실시하였다. 녹색 PE필름 멀칭처리에서 시들음병 발생은 10월 초순부터 시작되었고 무멀칭처리보다 더 증가하였다. 녹색 PE피름 멀칭 처리는 점박이응애의 피해율이 무멀칭처리보다 높았다. 녹색 PE필름 멀칭처리의 상토내 온도는 무멀칭처리보다 증가했지만 대기내 상대습도는 감소하였다. 이런 결과로 딸기 수경재배에서 베드의 무멀칭처리는 시들음병과 점박이응애 발생을 낮추는 효과가 있다고 판단된다.

• 한국산학기술학회논문지
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• 제18권5호
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• pp.302-307
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• 2017

북극해 지역은 해수면의 변화와 다양한 환경적 요인들로 인해 유빙들이 형성되고 이는 자원 개발을 위한 해양시스템 및 운항선박과의 충돌사고에 의한 피해를 유발하고 있다. 극지방의 유빙은 운항중인 석박뿐만 아니라 한 장소에서 오랜 기간 작업을 수행하는 해양자원 시추 및 생산 시스템에 대한 잠재적 사고요인이 된다. 유빙과의 충돌사고 방지를 위해 북극해의 해양자원 시추 및 생산 시스템과 북극 항로를 운항하는 선박에서는 위성 영상 정보 및 탐지 레이더를 이용하여 유빙을 탐지하고 있다. 하지만 가시광선 위성영상은 야간 활용이 불가능하고, 레이더에 의한 탐지도 소형 유빙에 대해서는 탐지확률이 현격히 저조해지는 문제가 있다. 본 연구에서는 유빙의 탐지를 위해 주야간 운용이 모두 가능한 열화상 시스템의 이용 방안에 주목하고 유빙의 탐지특성에 관한 실험적 연구를 수행하였다. 열화상 시스템의 야간 운용성을 파악할 수 있도록 실험조건을 설정하고 계측 각도 변화에 따른 열화상을 계측하였으며, 실험과 동일 조건에 대한 유빙과 해수의 복사에너지를 이론적으로 계한함으로써 계측 결과와의 상호 관계를 파악하였다.