• Proceedings of the Membrane Society of Korea Conference
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• 2004.07a
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• pp.57-68
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• 2004

A demonstrative operation of a membrane system with its caparity of 3,600m$^3$/d was carried out using reservoir water as raw water for the application of membrane filtration system to drinking water treatment. The operation was undertaken at a constant flux of 0.9 m$^3$/m$^2$/d for three months. Backwashing with NaClO of 3 ppm was allowed for 30 seconds every 20 minutes of filtration. Physical cleaning was introduced after 69 times of filtration/backwashing cycle with air-scrubbing and backwashing for 1 minute, and flushing for 2 minutes. In this study, water treatment performance was investigated compared with the existing rapid sand filtration process. The membrane system was operated with no significant problems during the test period. Higher water quality was obtained in the membrane filtration than in the rapid sand filtration in terms of particulate matters such as turbidity and microbes. Although the finished water of the membrane filtration contained slightly higher concentration in dissolved matters than that of the conventional one, it met the drinking water standard. The demonstrative operation showed that membrane filtration has a reliability in drinking water treatment. Researches should be needed on cost analysis through long-term operation and optimization of operation condition for further application.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.474-478
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• 2010

Hybrid rocket combustion experiments using liquefying diaphragm made by blended liquefying fuel with 10 wt% of LDPE were performed. Results of experiments were compared to the those of pure paraffin. In case of using liquefying diaphragm, regression rate of rear fuel grain, characteristic velocity and specific impulse highly increased due to the induced turbulent intensity and heat transfer. The serious combustion instability was not observed in analysis of combustion instability. These results can imply that the liquefying diaphragm is efficient to improve low combustion efficiency in hybrid rocket using liquefying fuel.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.469-473
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• 2010

In this study, combustion tests using liquefying fuels with fast regression rate were performed. The chamber pressure oscillation was analyzed and hazards of combustion instabilities were examined. In case of Liquefying fuel with fast regression rate, the amplitude of chamber pressure oscillation was increased compared to the polymeric fuels. However, the critical combustion instability can hardly occur in liquefying fuel. This is because the rapid change of inner chamber diameter limits the amplification of chamber pressure oscillation. The chamber pressure oscillation due to the large increase of fuel production and the vortex shedding in pre-chamber violently occurs during combustion using single-port axial injector.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.206-209
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• 2010

The visualization device for hybrid rocket is fabricated to investigate the combustion phenomena. Visualization device were composed with ignition system, oxidizer supply system, control system and data acquisition system, combustion visualization system. GOX as oxidizer and HDPE, Paraffin-LDPE Blending, Paraffin sd were used. As results, combustion phenomena and fuel droplet entrainment were observed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.724-729
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• 2017

The interaction between the flow of the nozzle and the acoustic motion in the combustion chamber acts as an important factor in suppressing combustion instability where nozzle damping effect can be evaluated by nozzle admittance. In this study, Modified Impedance Tube experiment is implemented to predict the acoustic nozzle damping effect. The experimental admittances are compared to numerical admittances values which are calculated from one-dimensional linearized Euler equation of Crocco's theory. As a result, it was possible to identify qualitatively the tendency between increasing and decreasing parts. Also, Efficient frequency bands of nozzle attenuation can be predicted.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.239-242
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• 2008

Combustion Characteristic with initial port-diameter of fuel was studied in hybrid propulsion system using cylindrical single port-grain. In order to understand a variation of combustion characteristic with initial port-diameter, experimental studies were performed with the GOX and $GN_2O$ as oxidizer, and PE as fuel. As results, burning rate decreased with increase of initial port-diameter of fuel. And the variation of burning rate with using $GN_2O$ is smaller than using GOX.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.258-262
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• 2011

The hybrid combustion experiments using non-combustible diaphragm were performed for characteristic of regression rate and combustion efficiency. Results of experiments using diaphragm were showed that the regression rate and efficiency were increased. In addition, the larger difference between fuel grain port and diaphragm port increase the regression rate and efficiency. The modified regression rate equation was proposed with the port area ratio of fuel and diaphragm.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.247-250
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• 2008

An experimental investigation was conducted to clarify the combustion characteristics and merge characteristics of PMMA-GOX and PE-GOX hybrid motor using multi-port fuel grain configuration. The regression rate of multi-port fuel grain is higher than the regression rate of single-port fuel grain by thermal conduction and chamber pressure. The merge of multi-port has an effect on hybrid rocket performance by change of a combustion area.

• Journal of the Korean Institute of Rural Architecture
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• v.21 no.1
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• pp.9-16
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• 2019

The decrease in population of school age is one of major influencing factor of transformative educational environment. After the nineteen eighties, the population of South Korea has increased step by step, but the population of school age has been decreasing rapidly by low birth rate. As a result, closed school by merger and abolition of small school occurred all over the country. The closed school needed effective function as center of local community. Consequently the purpose of this study is to provide basic data for effective policy making of closed school by comparative analysis of educational environment such as number of students, schools, students per class, status of usage of closed school of the east area and the west area divided by The Tae Baek Mountains in the Gangwon-do, which has the least students in the nationwide. The results of this study are summarized as follows: 1) Gangwon-do has high decreasing rate of population, schools and students compared with other provinces. However it has significantly low number of students per class. 2) The number of students, schools of the west area in Gangwon-do outnumbers that of the east area. However the number of students per class of the east area in Gangwon-do lesser than that of the west area.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.25-32
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• 2022

The purpose of this study is to provide design guidelines necessary for creating disability-friendly campuses. To this end, a literature survey and a survey on the current educational welfare facilities for disabled college students were conducted. The fact-finding survey was conducted in writing and visiting evaluations on 19 campuses located in Gangwon-do(province). The results of this study are summarized as follows: 1) The college enrollment rate of the disabled has doubled since 2000, but it was found to be half of the enrollment rate based on school enrollment, and the number of students who gave up in the middle is increasing. This is due to an obstacle in the learning environment, so it is necessary to improve welfare facilities. 2) As a result of evaluating the status of educational welfare support for students with disabilities, it was found that the overall evaluation result was improved, but the absolute evaluation result was less than 70%, and it was not improved. 3) As a result of evaluating the actual conditions of the intermediate facilities, indoor facilities, sanitary facilities, guidance and other facilities, and unit spaces, it is necessary to expand and improve them due to the lack of disabled parking marks, continuity of access roads, pedestrian safety passages, lifts, and rest areas for the disabled.