• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.139-150
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• 2010

최근 한국에서는 세계적인 녹색기술을 맞아 향후 차세대 교통 시스템으로서 튜브 트레인 시스템의 본격적인 연구가 진행되고 있다. 한국 철도기술연구원(KRRI, Korea Railroad Research Institute)에서 튜브 트레인 시스템의 건설을 위한 목적으로 연구가 진행되고 있다. 본 논문에서는 기초연구의 일환으로 축대칭하며 긴 형상의 수송체가 가지는 다양한 튜브(터널) 내부의 압력, 막힘비율, 운행속도를 파라미터로 선정하여 전산해석을 수행하였다. 세부사항으로는 동일 형상의 운송체가 동일 운행속도를 가지고 일반적 압력의 개활지(오픈 시스템, 개활지 운행)를 운행할 때와, 다양한 환경(튜브 내 압력, 막힘비율, 운행속도)의 튜브 내부를 운행할 때에 대하여 튜브 트레인의 공력특성 연구를 수행하였다. 이를 통하여 다양한 운행속도-막힘비율 별로 개활지와 동일 에너지 효율 나오는 튜브 내 압력(P-D 관계)을 계산하였고, 막힘비율 증가에 따른 튜브 내 감압 정도(P-${\beta}$ 관계), 다양한 막힘비율-튜브 내 압력 별로 운행속도에 따른 전체 항력 양상(D-V 관계)을 보여 주었다. 그리고 개활지 운행시와 튜브 내부 운행시의 에너지 효율(주행저항)을 비교하였고, 튜브 내부 운행 시 트레인이 갖는 효율과 관계되는 충격파 발생의 임계속도(critical V-B 관계) 및 한계속도(V-P 관계)를 얻을 수 있었다. 이러한 연구의 결과는 튜브 시스템 설계 및 건설에 꼭 필요한 것이며 가이드라인을 제시했다.

• 한국식품영양학회지
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• 제26권3호
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• pp.453-458
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• 2013

본 연구에서는 매실의 첨가에 따른 돼지막창의 품질특성 변화를 확인하였다. 가열하지 않은 막창(생막창)과 $100^{\circ}C$에서 10분 동안 가열한 막창(가열막창)의 pH는 매실의 첨가에 따라 낮아졌다. L값과 a값은 생막창과 가열막창 모두 저장기간에 따른 변화는 미미한 것으로 확인되었다. 생막창의 b값은 저장 초기에는 매실의 첨가에 따른 상승이 확연하였으나, 저장기간이 지속됨에 따라 그 차이가 점점 줄어들었다. 가열막창의 b값은 매실의 첨가에 따른 b값이 약간 낮아졌으며, 저장기간에 따라 약간 감소하는 경향을 나타내었다. ${\delta}T$ 값은 생막창과 가열막창 모두 L값과 거의 유사한 패턴을 보였다. 생막창과 가열막창 모두에서 TBA가는 매실의 첨가농도에 비례하여 유의적으로 낮아졌으며, 매실 5% 첨가구와 10% 첨가구는 거의 TBA가에서 차이가 없었다는 것으로 확인되었다. VBN가는 매실을 첨가할 경우 생막창과 가열막창 모두에서 VBN의 증가속도는 대조구에 비해서 낮은 것으로 확인되었다. 저장 6일째부터 매실의 첨가농도에 비례하여 VBN가가 낮아졌으며, 매실을 5% 첨가할 경우 저장을 4일 이상 지연시킬 수 있는 것으로 확인되었다.

• 한국식품영양학회지
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• 제28권4호
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• pp.628-634
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• 2015

고추 추출액의 수율 및 생리적 기능성을 향상시키기 위하여 고추에 cellulase(C 처리군), pectinase(P 처리군), amylase(A 처리군)를 각각 또는 이들 효소들을 혼합(CP, CA, PA 및 CPA 처리군) 첨가하여 2~8시간동안 가수분해시킨 후 가열처리하고, 여과시킨 추출액에 대하여 이화학적 및 관능적 평가를 측정하였다. 효소 처리 고추 추출액의 수율은 효소 처리를 하지 않았을 때 38.84% 정도로 매우 낮게 나타났지만, 효소처리군이 높은 수율을 보였고, 효소 단독처리군보다는 병용처리 시 수율이 증가하였으며, 효소 처리 시간이 길어질수록 유의적으로 수율이 증가하는 것으로 나타났다. 특히 cellulase + pectinase + amylase(CPA) 복합처리군은 추출수율이 74.37%까지 증가하였다. 가용성 고형분의 함량변화는 대조군의 경우에는 8.51% 를 나타내었으나, 효소처리군은 대조군보다 높은 함량을 나타내었으며, CA 혼합처리군과 CPA 혼합처리군이 가장 높은 가용성 고형분 함량을 보였다. 환원당의 함량 또한 효소 처리에 의하여 증가하는 것으로 나타났다. 효소 처리에 의한 색도의 변화에서는 대조군과 효소처리군 간에 색도의 변화를 보이지는 않았다. 효소 처리한 고추 추출액에 대한 관능검사 결과에서는 전반적으로 효소 처리를 하지 않은 대조군에 비하여 효소 처리 시 기호도 면에서 우수한 것으로 나타나, 고추 추출물 제조를 위한 효소 처리는 수율 및 기호도 증진을 위한 좋은 방법으로 사료된다.

• 한국ITS학회 논문지
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• 제21권6호
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• pp.97-114
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• 2022

지하도로의 유입연결로 합류부는 지상도로와 달리 터널로 인하여 시계확보에 제약을 받는다. 본 연구에서는 시계확보에 관련 설계요소가 합류부 주행에 미치는 영향을 분석하기 위하여 주행 시뮬레이터를 활용한 가상주행실험을 수행하였다. 가상주행환경 구축시 시계확보 설계요소를 시나리오에 반영하기 위하여 갈매기차로 길이와 본선차량 접근속도를 시나리오로 구분하여 운전자 주행행태를 분석하였다. 시나리오간 속도 측면의 분석지표와 차로변경지점, 운전자 주시 비율 분석결과는 일관성 있는 방향으로 도출되었고, 통계적 유의성을 검토하였다. 그 결과, 본선 접근속도가 더 높은 시나리오에서 갈매기차로 길이에 의한 특정 시나리오 사이에 운전자 주행행태의 차이가 있는 것으로 나타났다. 이러한 결과를 바탕으로 지하도로 유입연결로 합류부의 주행안전성 향상을 위한 설계방향과 시사점을 제시하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1342-1351
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• 2011

Nowadays rolling stock has become a fast and convenient transportation and increased in its demands. But the improvement of speed has result in increase of aerodynamic noise and therefore residential districts near by the railroad are now constantly suffering from the racket. Thus the study regarding rolling stock's environmental noise measurement and appraisal has become important. The case of environmental noise, there are no changes of tone so prediction can be made by reducing areas around the railway. This is part of the study which estimates the noise around the railway using scaled model, and the source of the noise has been researched on. The scaled model of rolling stock will have to be able to make high frequency and it needs to be spread out in a short amount of time. When popping a balloon or firing a gun fits its condition and this study analyzed the characteristics of these two different noises. Measurement was held on a wide vacant lot and the reflection effect of the ground is additionally examined. It is judged to be used in the future when predicting the environmental noise of railway vehicles.

• Advances in concrete construction
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• 제9권3호
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• pp.327-335
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• 2020

Concrete pipes are considered important structures playing integral role in spread of cities besides transportation of gas as well as oil for far distances. Further, concrete structures under seismic load, show behaviors which require to be investigated and improved. Therefore, present research concerns dynamic stress and strain alongside deflection assessment of a concrete pipe carrying water-based nanofluid subjected to seismic loads. This pipe placed in soil is modeled through spring as well as damper. Navier-Stokes equation is utilized in order to gain force created via fluid and, moreover, mixture rule is applied to regard the influences related to nanoparticles. So as to model the structure mathematically, higher order refined shear deformation theory is exercised and with respect to energy method, the motion equations are obtained eventually. The obtained motion equations will be solved with Galerkin and Newmark procedures and consequently, the concrete pipe's dynamic stress, strain as well as deflection can be evaluated. Further, various parameters containing volume percent of nanoparticles, internal fluid, soil foundation, damping and length to diameter proportion of the pipe and their influences upon dynamic stress and strain besides displacement will be analyzed. According to conclusions, increase in volume percent of nanoparticles leads to decrease in dynamic stress, strain as well as displacement of structure.

• 한국환경보건학회지
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• 제31권3호
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• pp.215-220
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• 2005

The atmospheric transportation and dispersion processes of air pollutants are important issues in dealing with air pollution problems. Air pollutants originated from biological and anthropogenic activities are not only limited to the local emission sources, but could also be transported and dispersed to other regions by synoptic weather systems. Besides, the complexity of topography of central Taiwan helps accumulating air pollutants to promote high-concentration episodes. The techniques of tethersonding were applied to monitor the vertical profiles of winds, air temperatures and humidity, as well as to collect air samples, to be analyzed for pollutants $(O_3,\;NO_2,\;NO\;and\; NMHC)$ from the ground up to 1000m. A time period of about one week, 19-26 October 2002, was chosen as the sampling period due to the high frequency of episode occurrence in autumn based on the past records. Associating with the analysis of weather patterns, the atmospheric characteristics over high-concentration areas can be resolved in more detail. The result of the tethersonding studies showed that weak northerly sea breeze (with thickness about 300m) with low wind speed (about 1 to 2 m/sec) could help develop high ozone concentrations in the down-wind areas. It is also important to have a built-up aloft of precursors and ozone to develop high concentration on the previous day.

• International Journal of Concrete Structures and Materials
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• 제18권2E호
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• pp.97-102
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• 2006

In this study, the effect of supplementary materials(GGBS, PFA, SF) on sulfuric acid corrosion resistance was assessed by measuring the compressive strength, corroded depth and weight change at 7, 28, 56, 91, 180 and 250 days of immersion in sulfuric acid solution with the pH of 0.5, 1.0, 2.0 and 3.0. Then, it was found that an increase in the duration of immersion and a decrease in the pH, as expected, resulted in a more severe corrosion irrespective of binders: increased corroded depth and weight change, and lowered the compressive strength. 60% GGBS mortar specimen was the most resistant to acid corrosion in terms of the corroded depth, weight change and compressive strength, due to the latent hydraulic characteristics and lower portion of calcium hydroxide. The order of resistance to acid was 60% GGBS>20% PFA>10% SF>OPC. In a microscopic examination, it was found that acid corrosion of cement matrix produced gypsum, as a result of decomposition of hydration products, which may loose the structure of cement matrix, thereby leading to a remarkable decrease of concrete properties.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2006년도 춘계학술발표회 논문집
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• pp.53-58
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• 2006

Although the uninhabitable islands are part of national property, those are not systematically managed and controlled in Korea. In this study, the positioning standards for uninhabitable islands are suggested with proper surveying methods. To establish the standards, the current status on managing the uninhabitable islands in foreign countries are investigated and analyzed. It was found that it is necessary to establish the ocean geodetic network based on a sound and systematic plan. In Korea, the ocean geodetic network can be established by combining the National control point and territorial sea control points. We suggested that one or two third or fourth control points are required to be established in total of 2,679 islands with connection to the 47and 249 first and second-order control points. It is expected that this network will provide ground control points for aerial and satellite images for large scale ocean mapping. In addition, close cooperation among the related departments such as Ministry of Construction & Transportation, National Geographic Information Institute, Ministry of Government Administration and Home Affairs, Ministry of Maritime Affairs and Fisheries, and Ministry of Environment is necessary for successful management on uninhabitable islands.

• 한국해양공학회지
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• 제17권2호
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• pp.8-13
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• 2003

Soil, ground water, and sea bed are exposed to a continuous accumulation of polluted materials, causing serious environmental damage. It has been reported that such pollution causes a massive mortality of fish stock in rivers due to the resuspension of toxic chemicals, occurring during strong wind conditions. Therefore, it becomes apparent that there is an immediate demand for the restoration treatment of polluted river bed (or sea bed) sediment layers. Pollution levels of major rivers and ports, such as Paldang, Kyungan rivers, and Masan port, are becoming of great public concern, and are posing a serious environmental threat. In particular, the pollution of the Shi-hwa river has become a nation wide issue for the last few years. In spite of such public concern, the pollution levels of such rivers or ports are worsening everyday. In this study, an environmentally sound engineering package is introduced that helps to restore the polluted river bed or sea bed sediments. This engineering package consists of a suction facility, followed by a series of mechanical, chemical, and biological treatment units. The suction facility is designed to minimize secondary pollution that occurs from the resuspension of toxic materials during suction. The sea bed cleaning engineering package is designed to be installed on the top of a floating barge. Such a combination of environmental plant and shipbuilding technology provides a cost-effective solution, minimizing the transportation between suction and treatment facilities.