• 한국유체기계학회 논문집
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• 제13권1호
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• pp.9-16
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• 2010

In the power generation industry, various efforts are needed to cope with tightening regulation on carbon dioxide emission. Integrated gasification combined cycle (IGCC) is a relatively environmentally friendly power generation method using coal. Moreover, pre-combustion $CO_2$ capture is possible in the IGCC system. Therefore, much effort is being made to develop advanced IGCC systems. However, removal of $CO_2$ prior to the gas turbine may affect the system performance and operation because the fuel flow, which is supplied to the gas turbine, is reduced in comparison with normal IGCC plants. This study predicts, through a parametric analysis, system performances of both an IGCC plant using normal syngas and a plant with $CO_2$ capture. Performance characteristics are compared and influence of $CO_2$ capture is discussed. By removing $CO_2$ from the syngas, the heating value of the fuel increases, and thus the required fuel flow to the gas turbine is reduced. The resulting reduction in turbine flow lowers the compressor pressure ratio, which alleviates the compressor surge problem. The performance of the bottoming cycle is not influenced much.

• 전기학회논문지
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• 제65권7호
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• pp.1151-1160
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• 2016

In recent years, the energy storage systems such as LiB, NaS, RFB(Redox-Flow Battery), Super- capacitor, pumped hydro storage, flywheel, CAES(Compressed Air Energy Storage) and so on have received great attention as practical solutions for the power supply problems. They can be used for various purpose of peak shaving, load leveling and frequency regulation, according to the characteristics of each ESS(energy storage system). This paper will focus at 1 MWh RFB system, which is being developed through the original technology project of energy material. The output of ESS is mainly characterized by C-rate, which means that the total rated capacity of battery will be delivered in 1 hour. And it is a very important factor in the ESS operation scheduling. There can be several options according to the operation intervals 15, 30 and 60minutes. The operation scheduling is based on the optimization to minimize the daily electricity cost. This paper analyzes the cost-saving effects by the each operating time-interval in case that the RFB ESS is optimally scheduled for peak shaving and load leveling.

• 한국수자원학회논문집
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• 제54권3호
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• pp.203-215
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• 2021

본 연구에서는 유역내 댐 건설과 하천내 식생성장으로 육역화 현상이 진행되는 내성천 환경 변화의 원인을 파악하기 위해 내성천 유역에 위치한 3개 관측소를 대상으로 2010년부터 2019년까지 관측된 수문자료와 항공사진 및 지형자료를 수집하여 수문특성에 따른 수위-유량관계 변화 및 횡단면의 침식·퇴적 변화율을 분석하였다. 또한 상류 지류인 월호교 관측소에서 인위적인 유량 조절 유무에 따른 영향을 비교하였다. 분석결과, 내청천에서는 2013년부터 2015년까지 지속적인 가뭄에 의해 홍수터에서는 식생활착 및 식생사주 면적 증가로 육역화가 진행되었고, 저수위에서는 흐름부 축소, 유속 및 하상소류력 증가로 지속적인 하상침식이 발생한 것으로 판단되었다.

• 한국전자통신학회논문지
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• 제18권3호
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• pp.387-396
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• 2023

현재 기상관측에 사용되는 대표적인 장비는 기상탑과 윈드라이다가 사용되고 있다. 국제 규정에 의하면 기상탑은 단독 측정이 가능하나 윈드라이다 경우 40m 기상탑 혹은 풍력발전기 블레이드 최하단의 높이에 맞는 기상탑을 필수로 설치하고 측정데이타를 보정하여야 한다. 난류는 특성상 100m 이하의 고도에서 빈번하게 발생하며 기상탑 보다는 윈드라이다가 난류의 영향을 많이 받는다. 그럼에도 불구하고 기상탑에 대한 난류 강도는 국제 규정에 명시되어 있으나 윈드라이다 대해서는 별도로 명시하지 않고 있다. 본 연구는 동일한 조건에서 기상탑과 윈드라이다에서 측정된 데이터를 수집하고 불확도 및 난류 강도 비율을 분석한다. 데이터를 분석한 결과 난류 강도 비율이 3%를 초과하는 구간이 부분적으로 존재한다. 따라서 윈드라이다에 대한 난류강도 오차율을 국제 규정에 명시할 것을 제안한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3294-3299
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• 2007

These days the exhaustion of petroleum resources and environmental problems are getting serious. Many researchers are focused on low emission and high performance vehicles. Therefore, we should concern about emission regulation when we design a new car. In this study, we investigated the characteristics of the traditional mechanical engine cooling systems which control the engine temperature using engine speed and wax type thermostat. This experiment used three components which are Radiator fan, water pump and water valve controlled by an electronic system based on the engine status (load, speed). We elucidated how different between traditional mechanical cooling system and electronic cooling system which control coolant temperature and coolant flow rate in a DI diesel engine in this paper. The results revealed a fuel saving and an emission (CO, HC) reduction on NEDC cycle.

• 한국유체기계학회 논문집
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• 제16권1호
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• pp.5-10
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• 2013

The performance of screw air compressor is affected by rotor profile, lobe number, air end wrap angle, rotor L/D ratio, suction and discharge ports, revolutions of air end and load regulation control, etc. In general, an efficient screw compressor needs a rotor profile of which has a large flow cross-section area, short sealing lines and a small blow-hole. In this study, experimental study was performed with newly designed $5{\times}6$ rotor profile and various shapes of air end. Results show that the measured specific power consumption of the newly designed screw compressor appeared to be lower than any other published data for the equivalent screw compressors manufactured.

• 대한본초학회지
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• 제22권3호
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• pp.127-132
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• 2007

Objectives : FLOS CHRYSANTHEMI (FC) has been reported to possess a variety of pharmacological activities. However, the effect of FC on the dendritic cells has not been determined. Methods : To examine the effect of FC on the immune response, we used several methods such as flow cytometric analyses, enzyme-linked immunosorbent assay. Results : 1. FC inhibited lipopolysacchride (LPS)-induced maturation of bone marrow-derived dendritic cells (BMDC) such as down-regulation of MHC class II and CD40. 2. FC also inhibited uptake of FITC-Dextran in BMDC stimulated with LPS. 3. Furthermore, FC inhibited several kinds of cytokine production such as TNF-a, IL-6 and IL-12 in BMDC. Conclusions : These results suggest that FC plays pivotal role m the development of inflammatory diseases.

• 한국공간정보시스템학회 논문지
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• 제11권1호
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• pp.177-182
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• 2009

위치기반서비스는 위치정보를 기반으로 하는 다양하고 광범위한 서비스를 의미한다. 이러한 위치기반 서비스들은 개인 위치정보 보호를 위하여 위치정보보호법에 의한 규제를 받고 있다. 본 논문에서는 위치정보보호법에 의한 위치정보의 형태와 의미를 살펴보고, 위치정보 흐름을 분석하여 그 사용방법 및 한계에 대하여 살펴보도록 한다. 이를 바탕으로 위치정보가 다양한 분야의 서비스 개발 등에 활용되어 보다 광범위하게 활용되었으면 한다.

• 대한예방한의학회지
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• 제10권2호
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• pp.121-129
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• 2006

BACKGROUND : Socheongryong-Tang(小靑龍湯, SCRT), a herbal medicine, has been widely used for the control of respiratory disease in Eastern countries. Recent years SCRT was known as anti-allergic agent. However, its therapeutic mechanisms, especially an inhibitory effect on inflammatory cell infiltration and airway remodeling in allergic asthma are unclear. METHODS : We investigated the effects of SCRT on levels of IL-4, and IFN-g using flow cytometric analysis and infiltration of inflammatory cells in bronchoalveolar lavage fluid(BALF) using cytospin methods in allergen-induced asthma. RESULTS : SCRT decreased levels of IL-4, a Th2-driven cytokine. But INF-g, a Th1-driven cytokine, was not changed. With SCRT treatment, infiltration of inflammatory cells showed reduced tendency. CONCLUSION : In conclusion, we demonstrated that regulation of Th1/Th2 imbalance may be one of mechanism contributed to reduction of inflammatory cell infiltration.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.515-518
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• 2003

Mathematical models can be used to evaluate the effects of operational alternatives of dam on the downstream aquatic environment. An unsteady, one-dimensional water quality model, CE-QUAL-RIVI was calibrated and validated in Geum river as a sub model for the realtime water management system in the basin. The main usage of the model within the system is to predict the effects of flow regulation by Daecheong Dam on the downstream water quality. The validated model was then used to simulate dynamic water quality changes at several key stations responding to different scenarios of reservoir releases under a hypothetical spill condition. The model showed fairly good performance in the simulation of hydrodynamic and mass transport processes under highly unsteady conditions.