• 설비공학논문집
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• 제28권4호
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• pp.165-170
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• 2016

Long-term performance of the enthalpy exchange element is a topic of current interest due to the concern of possible performance degradation over time. In this study, a 350 CMH enthalpy recovery ventilator equipped with an enthalpy exchange element was installed in an office room, and the performance has been traced over the past 5 years. The appearance, overall dimension, thermal performance, leakage ratio and anti-bacterial performance were checked annually. Results showed that the change in thermal performance (sensible, latent and enthalpy efficiency) was negligible with periodic cleaning with an air gun. However, the leakage ratio increased with time, measuring 7.3% after 5 years. Anti-bacterial test revealed that no bacteria were found during the test period. The largest change in the dimension occurred at the middle location of the element, although the change was less than 2% of the initial value.

• 한국유체기계학회 논문집
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• 제16권2호
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• pp.15-20
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• 2013

An aero-acoustic performance analysis method of regenerative blower is developed as one of the FANDAS codes. The aerodynamic performance of regenerative blower is predicted by using momentum exchange theory coupled with pressure loss and leakage flow models. Based on the performance prediction results, the noise level and spectrum of regenerative blower are predicted by discrete frequency and broadband noise models. The combination of the performance and the noise prediction methods gives aero-acoustic performance map and noise spectrum analysis results, which are well-agreed with the actual measurement results within a few percent relative error.

• Journal of Korean Dental Science
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• 제5권2호
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• pp.60-67
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• 2012

Purpose: To test the apical leakage prevention performance of three different materials through protein leakage procedures using bovine serum albumin (BSA) and Bradford protein reagent. Materials and Methods: A total of 60 human single-rooted teeth were divided into 4 groups, and conventional root canal filling was done. The root was cut 3 mm from the apex, and a cavity was formed. Proroot MTA (MTA), Fuji II LC (GI), Fuji II LC with XP bond (GIA), and Caviton (CA) were used as experimental materials to fill the cavity in a retrograde filling manner. The extent of BSA leakage was then measured with a ultraviolet visible spectrophotometer 24, 48, and 72 hours after filling. Result: After 24 hours, among the 15 teeth of each group, 2 in MTA, 4 in GI, 3 in GIA, and 7 in CA showed leakage. After 48 hours, 3 in MTA, 5 in GI, 5 in GIA, and 10 in CA had leakage and discoloration. After 72 hours, among the 15 teeth of each group, 3 in MTA, 6 in GI, 5 in GIA, and 10 in CA showed leakage. The leakage in the CA group was greater than that in the MTA group at 48 and 72 hours based on Fisher's exact test (P=0.025), and the difference was statistically significant. Similarly, the leakage in the CA group was greater than that in the MTA group over time based on the Kaplan-Meier survival estimate (P=0.011), and the difference was statistically significant. Conclusion: Glass ionomer, glass ionomer after adhesive application, and MTA all showed leakage. Caviton showed greater leakage compared to MTA 48 and 72 hours after filling, and the difference was statistically significant; thus suggesting that Caviton is not appropriate as retrograde filling material considering its sealing ability.

• 한국건축시공학회지
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• 제6권1호
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• pp.87-91
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• 2006

Since water leakage and cracks are not the source of serious problems such as long-term lowering of performance and durability of a stricture, including damages to operating facilities of a structure, damages to internal finishing materials, exhibition, and goods, and pollution of residential environment, they might have led to development of positive coping skills; however, an instant loss of lives or property due to earthquake, explosion, typhoon, or a fire was indeed neglected. In these days, repair materials for leakage cannot help but being taken in temporary way without any noticeable countermeasure. This kind of repair is socially criticized many times that is defective construction even if this costs a lot. It was not arrange the standard for construction methods of sealer of injection type for leakage maintenance, even it has been used various type of construction methods for leakage part. In conclusion, we suggest that the construction methods of sealer of injection type for leakage maintenance for leakage to establish the leakage repairing technology as increase of structure demand. Therefore, it would be possible to provide a stage-by-stage solution by developing systematic research activities among the industry, schools, and research institutes to spread maintenance management techniques globally through technical solution to water leakage and cracks, acquisition of structural safety with prolonged durability for life cycle, reduction of water leakage repair expense s, and so on.

• 한국화재소방학회논문지
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• 제31권1호
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• pp.1-9
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• 2017

본 연구에서는 거실제연설비가 설치된 철도 지하환승통로에 현장성능평가시험인 제연 TAB(Test, Adjusting, Balancing)를 실시하여, 제연설비 성능 확보에 미치는 영향을 분석하고 개선방안을 도출하였다. 제연 TAB는 지하환승통로의 제연설비 설계자료 분석, 제연덕트 누기테스트, 제연송풍기와 덕트의 풍량 및 풍속 측정, Smoke test로 나누어 진행되었다. 제연덕트 누기시험을 통해 누기율을 측정하여 덕트의 기밀성을 확인하였고, 흡입측 덕트 정압손실로 인한 제연풍량 부족의 문제점을 개선하여 송풍기의 성능을 확보하였다. 또한, Smoke test을 통해 예상제연구역별 제연댐퍼 동작 시 자연풍, 열차풍 영향으로 인한 문제점을 분석하고 개선하여 예상 제연구역 내 제연이 원활하게 이루어짐을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1705-1708
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• 2006

Nanocrystalline silicon (nc-Si) based TFTs were developed using a conventional PECVD production system. Devices exhibit very interesting characteristics, in particular when using a bi-layer structure which reduces leakage current and improves subthreshold area. Good stability and low leakage current make these devices suitable for the fabrication of low-cost and high performance AMOLED displays.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 춘계학술발표대회 개요집
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• pp.117-119
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• 2003

Power plant efficiency and availability depend greatly on condenser performance. However, during commissioning of Yeonggwang #1/2 steam condenser sodium leakage occurred, because of tube to tubesheet only roll expanding. Therefore this report is explaining that pre-test for the shake of improvement reliable repair processes & selected sampling tube re-expansion in-situ applications.

• 한국정밀공학회지
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• 제14권4호
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• pp.56-63
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• 1997

Sealing of lubricant-air mixture in the high performance machining center is one of most the important characteristics to carry out enhanced lubrication. High speed spindle requires non-contact type of sealing mechanism. Evaluating an optimum seal design to minimize leakage is concerned in the aspect of flow control. Effect of geometry and leakage path are evaluated according to variation of sealing geometry. Velocity, pressure, turbulence intensity of profile is calculated to find more efficient geometry and variables. This offers a methodological way of enhancement seal design for high speed spindle. The working fluid is regarded as two phases that are mixed flow of oil phase and air phase. It is more reasonable to simulate an oil jet or oil mist type high speed spindle lubrication. Turbulence and compressible flow model are used to evaluate a flow characteristic. This paper considers a design effect of sealing capability of non- contact type seals for high speed spindle and analyzes leakage characteristics to minimize a leakage 7 on the same sealing area.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.73-74
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• 2017

Below-grade concrete structure in residential buildings are exposed to various cracking conditions in between installation, construction and usage. Leakage follows the cracks along the exterior wall and floor slabs, and leakage occurring in this conditioning brings about discomfort to the users inside the building. This study analyzes a survey on the causes of leakage in below-grade concrete structure and proposes a solution method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.136-141
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• 2011

In a power plant, an oil and steam leakage is generated once in a while. This is because the operating temperature and pressure of oil are very high. It is very difficult to monitor oil leakage, because oil leakage is almost invisible. Therefore a method to oil leakage detecting quickly and accurately is needs. In this paper, we proposed the method for the detecting oil leakage by using image processing and CCTV. To test the performance of this technique, experiments have been performed for simple case. Results show that the proposed technique is quite powerful in the oil leak detection.