• Clean Technology
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• v.27 no.2
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• pp.160-167
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• 2021

This study investigated the environmental effects of improving the general-type activated carbon adsorption tower used at the Sihwa/Banwol Industrial Complex with use of a cartridge-type activated carbon adsorption tower for the application of an activated carbon co-regenerated system. Four general-type activated carbon adsorption towers and two cartridge-type activated carbon adsorption towers were selected to analyze the properties of activated carbon and to compare the efficiency of reducing environmental pollutants. The results showed that the activated carbon used in the cartridge-type activated carbon adsorption towers was high quality activated carbon with an iodine adsorption force of more than 800 mg/g and that a good adsorption performance was maintained within the replacement cycle. From an analysis of the environmental pollutant reduction efficiency, it was confirmed that the cartridge-type activated carbon adsorption tower functioned properly as a prevention facility for handling emissions pollutants with a treatment efficiency of total hydrocarbons (THC), toluene, and methylethylketone (MEK) components of 71%, 77%, and 80%, respectively. The general activated carbon adsorption tower, which was confirmed to use low-performance activated carbon, had a very low treatment efficiency and did not function properly as a prevention facility for dealing with emission pollutants. It is believed that it is possible to reduce pollutants during operations by changing from the general-type activated carbon adsorption tower to a cartridge-type activated carbon adsorption tower.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.281-284
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• 2008

The flow of combustor in scramjet engine is supersonic speed. So residence time and mixing ratio are very important factors for efficient combustion. This study used open cavity on fuel/air mixing model and laser schlieren was carried out to investigate flow characteristics around a jet orifice and a cavity. A source of illumination has 10 ns endurance time so it can observe unsteady flow characteristics efficiently. Pressure was measured by varying momentum flux ratio. And the change of critical ignition point was observed to change of momentum flux ratio.

• Journal of Korea Water Resources Association
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• v.30 no.1
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• pp.63-73
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• 1997

Finite element model is established for the simulation of groundwater flow due to water curtain around underground oil storage Choleski decomposition method. The symmetric global conductance matrix is solved by vector storage Choleski decomposition method. The model is verified through comparison with the results of electric analogy. For the application of this model to real site, the finite element meshes are constructed according to representative vertical cross and longitudinal sections. In cross-sectional analysis, potential and flow distributions are compared based on the cavern pressure and horizontal water curtain. For longitudinal section, effects between nearly located caverns with or without vertical water curtain are analyzed. These results prove that the established model can be used as a tool for flow analysis around underground caverns.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.535-541
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• 1998

A 2 stage 6-pole bandpass filter(BPF) is designed and implemented by using triple-mode cavity for satellite payload system. The BPF has an 100 MHz bandwidth at the center frequency of 14.5 GHz, Ku-band. The cavity filter uses two orthogonal $TE_{113}$ modes and one $TM_{012}$ mode. The intercavity coupling between the adjacent cavities results in a Chebyshev response and is accomplished by H-field component of TE modes. The size and location of intercavity slot are determined by the coupling equation from H-field of TE resonant modes in circular cavity. The measured filter response agrees well with the theoretical data.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.4
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• pp.9-15
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• 2009

The flow of combustor in scramjet engine has supersonic speed so that the residence time and mixing ratio are very important factors for the efficient combustion. This study used open cavity(L/D=4.8) as a fuel/air mixing model. Laser schlieren visualization and pressure measurement were carried out to observe the flow characteristics around a jet orifice and a cavity at the time of fuel injection. As a result of 10ns laser schlieren, unsteady flow which was around the cavity could be observed effectively. Pressure was measured that momentum flux ratio(J) was changed. And the change of critical ignition point could be observed by the momentum flux ratio changed.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.1
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• pp.15-22
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• 2011

In this paper, cavitation patterns of model tests were compared with those of full-scale measurement for a propeller of crude oil carrier which was suffered from erosions on suction side of blade tip region. Cavitation tests were performed at design and ballast draft using model and full scale nominal wakes. A model ship and wire mesh method was used for the simulation of wake patterns of model nominal wakes. For the prediction of full-scale wake patterns, a RANS solver(Fluent 6.3) was used and wire mesh method was used for the simulation of the full scale wakes. Comparison results show that cavitation patterns using predicted full-scale wake patterns are closer to cavitation patterns of full-scale measurement at ballast draft condition. Also, cloud cavitations were observed on the position of eroded area at both full-scale measurement and cavitation tests using simulated full-scale wake patterns.

• Journal of Korean Library and Information Science Society
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• v.49 no.2
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• pp.301-326
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• 2018

The study is to find the possibility of cooperation between civil servants as a mediators for changing a society in a region into community of practice. "Community" is the value-oriented concept and exists in a local community, a community of practice and a organization that have the characteristic of "Community." Public libraries as "Community" have both characteristics of local community and community of practice. And public libraries as community gives public services for neighborhood region problem-solving to people. But in Korea, Residents autonomy system in Dong gives the service to people. They all conducts the business for changing a society in a region to community of Practice. Therefore the study conducted a survey about sense of community and necessity of cooperation in the business. The results are following: The group of higher awareness on community feels less needs to corporate the work in community than the group of lower awareness on community; The group of higher awareness on community or the group having more experience on community have lower job satisfaction. Therefore the motivation on working for community is needed for the mediator.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.931-946
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• 2018

In line with the increased usability of utility pipe conduits in urban areas, construction and R&D activities of utility tunnel, incorporated with the shield TBM method, are actively under way. The utility tunnels are installed through underground excavation, and thus are relatively weak in terms of construction safety. However, hazards associated with the utility tunnel construction have not been properly identified, despite the introduction of a policy to the 'Design for Safety' for the purpose of reducing accident rates in the construction industry. Therefore, in this study, following the derivation of hazards associated with utility tunnel, these hazards were then used as the basis to uncover key safety hazards requiring extensive management in a field, which were then used to conduct a risk assessment having applied the matrix method so that the results can be utilized in risk assessment during the stages of utility tunnel planning, design, and construction, while also serving as a data reference.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.01a
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• pp.259-260
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• 2013

본 논문에서는 1년 과정의 컴퓨터 프로그래밍 수업에 참여한 상위 수준 학습자들을 대상으로 맞춤형 학습을 위한 다양한 학습공동체를 운영하였을때 어떤 유형이 상위 학습자들에게 효과적인지를 분석하였다. 분석 결과, 동일한 상위 학습자가 튜터로 참여했을 때와 그렇지 않았을 때 성적 변화가 눈에 띄게 나타났으며 이것은 가르치는 활동이 본인의 학습 이해도를 높이는데 얼마나 영향을 미치는지를 보여주고 있다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.11b
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• pp.577-581
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• 2002

본 논문에서는 웹 기반의 멀티미디어 공동 작업 환경에서의 주소 동기화, 스크롤 동기화, 윈도우 크기 동기화, 양식 동기화, 마우스 위치 동기화, 주석 동기화 등 기능 중에서 주소 동기화 및 오류 제어에 대해서 기술한다. 웹 페이지를 하나의 미디어로 취급하여 여기서 발생하는 오류 및 제어에 대하여 기술한다. 오류 발생시에 복제형 구조에 기반한 응용 공유의 동작 원리를 이용하여 동기화를 잘 수행할 수 있는 환경을 제공한다.