• 방사성폐기물학회지
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• 제18권2_spc호
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• pp.237-245
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• 2020

사용후핵연료를 저장하는 볼트체결 저장용기의 격납경계를 형성하는 주된 구성요소는 금속 밀봉재이다. 이러한 금속 밀봉재는 열과 방사선에 의해 그 성질이 저하된다. 또한, 금속 밀봉재가 강한 열에 장기간 노출되면 크리프 현상이 발생한다. 이러한 크리프는 밀봉시스템에 응력 이완을 가져와서, 결국 밀봉재의 건전성을 해치게 된다. 이러한 응력 이완은 금속 밀봉재의 밀봉성능 저하로 이어지며, 저하의 정도에 따라 저장용기의 누설을 야기할 수 있다. 또한, 볼트 체결력의 감소도 밀봉성능 저하에 영향을 미친다. 본 논문에서는 금속 밀봉재의 격납건전성과 볼트체결력 감소를 평가하기 위해 수행한 가속화 시험의 결과에 대하여 기술한다. 전 시험기간 동안 각 시편에서의 누설률, 볼트 변형률, 금속 밀봉재 주변 온도를 계측하여 분석하였고, 금속 밀봉재는 저장기간 50년 동안 격납건전성을 유지함을 입증하였다. 또한, 가속화 시험의 타당성에 대해서 기술하였다.

• Nuclear Engineering and Technology
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• 제26권1호
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• pp.126-139
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• 1994

본 연구에서는 BETHSY 실험장치에서 수행한 6" 소형 냉각재 상실사고(LOCA) 실험을 최적 열수력 코드인 CATHARE2 V1.2와 RELAP5/MOD3를 이용하여 계산했다. 본 연구의 주 목적은 소형 LOCA시 관심을 가지는 주요 물리현상인 이상 임계유동, 감압과정, 노심수위 감소, loop seal clearing 등에 대한 두 코드의 소형 LOCA 계산모의능력을 평가하는 것이다. 두코드는 이상 유동현상의 전개 경향이나 발생시점을 비교적 잘 예측하는 것으로 나타났고, CATHARE2의 경우가 실험과 더 잘 일치했다. 그렇지만 두 코드는 loop seal clearing 현상, loop seal clearing 발생후의 노심수위, accumulator 유량거동 등의 예측에는 약간의 편차를 보였는데, 편차의 정도는 RELAP5가 CATHARE2보다 더 큰 것으로 나타났다. 두 코드의 편차요인을 보다 상세히 분석하기 위하여 계면 마찰력, mesh크기, 파단노즐 junction에서의 방출계수(Discharge coefficient)등에 대하여 민감도분석을 수행하였다. 그 결과 CATHARE2의 경우는 계면 마찰력을 증가시킴으로써 감압과정시 일차계통의 질량분포, 즉 증기 발생기 입구 공동(SG inlet plenum)에서의 차압과 Cross√er leg의 차압이 개선되었으며, 증기발생기 외측 열전달계수를 증가시킴으로써 중기발생기의 압력변화를 개선할 수 있었다. RELAP5의 경우는 어떤 하나의 입력변수를 변화시켜서 과도기의 결과를 개선할 수 없었으며 다만, 계면 마찰력 모델링에 여전히 많은 불화실성이 내포되어 있음을 확인했다.확인했다.

• 한국도로학회논문집
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• 제16권6호
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• pp.39-50
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• 2014

PURPOSES : The objective of this study is to evaluate the curing and adhesive behavior of asphalt emulsions including polymer-modified emulsions for chip seals and fog seals. METHODS : For the laboratory testing, the evaporation test, the bitumen bond strength (BBS) test, and the Vialit test are used. Also, the rolling ball test and the damping test are employed to evaluate the curing properties of the fog seal emulsions. In order to conduct all the tests in controled condition, all test procedures are performed in the environmental chamber. The CRS-2L and the SBS CRS-2P emulsions are used as a polymer-modified emulsion, and then unmodified emulsion, the CRS-2, is compared for the evaluation of chip seal performance. For the fog seal performance evaluation, two types of polymer-modified emulsions (FPME-1 and FPME-2) and one of unmodified emulsion, the CSS-1H, are employed. All the tests are performed at different curing times and temperatures. RESULTS AND CONCLUSIONS : Overall, PMEs show better curing and adhesive behavior than non-PMEs regardless of treatments types. Especially, the curing and adhesive behavior of PMEs is much better than non-PMEs before 120 minutes of curing time. Since all the test results indicate that after 120 minutes of curing time the curing adhesive behavior of emulsions, the early curing time, i.e., 120 minutes, plays an important role in the performance of chip seals and fog seals.

• 한국안전학회지
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• 제33권4호
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• pp.90-97
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• 2018

As the result(also after it's been carried out the damping force test with 800ea lateral dampers of 50ea trainset from entering heavy maintenance workshop to implement heavy maintenance inspection cycle, there were 86.25%(650ea) which were out of $350kg{\pm}15%$ of the standard value of damping force compared to the reference value. After the implementation of heavy maintenance inspection cycle, it's been examined damping force test with total samples 32ea(samples 8ea per a trainset) from actual running EMU 4ea trainset. As the result, percent defective was 84.4%(27ea), which was a very high level. System. The lateral damper's the failure cause of damping force defective was oil leakage caused by tearing crack of oil seal and foreign material in oil iron 473 ~ 1932 times higher than that of new oil, copper 36 ~ 98 times higher than that of new oil reduced oil amount cycling damping valve. It resulted from the change cause of damping force. In the static analysis on the shape of lateral damper oil seal's the existing and improved product, the stress of the improved product was smaller than that of the existing product. In the fatigue analysis, the existing product showed a low life in the upper area. However, in case of the improved product, it could be confirmed that the destruction did not occur up to the specified 1.0e + 006 cycles and the lifetime was further improved in most areas.

• Restorative Dentistry and Endodontics
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• 제45권2호
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• pp.24.1-24.9
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• 2020

Objectives: It is known that bioactive materials interact with the dentin to undergo biomineralization. The exact role of moisture in this interaction is unknown. Here, we investigate the effects of dentin moisture conditions on the dislocation resistance of two bioactive root canal sealers (MTA Fillapex [Angelus Solucoes Odontologicas] and GuttaFlow BioSeal [Colténe/Whaledent AG]) at 3 weeks and 3 months after obturation. Materials and Methods: Mandibular premolars (n = 120) were prepared and randomly divided into 3 groups based on the dentin condition: group 1, dry dentin; group 2, moist dentin; group 3, wet dentin. Each group was divided into 2 subgroups for root canal filling: MTA Fillapex and GuttaFlow BioSeal. Dislocation resistance was evaluated by measuring the push-out bond strength at 3 weeks and 3 months. Failure modes were examined under a stereomicroscope. Data were statistically analyzed by Kruskal-Wallis test with a significance level of 5%. Results: Moist dentin resulted in higher bond strength values for both materials at both time points. This was significantly higher than wet and dry dentin for both the sealers at the 3 months (p < 0.05), while at 3 weeks it was significant only for GuttaFlow Bioseal. The different moisture conditions demonstrated similar trends in their effects on the dislocation resistance of the 2 root canal sealers. Conclusions: The dentin moisture conditions had a significant impact on its interaction with the bioactive materials tested. Maintaining moist dentin, but not dry or wet dentin, may be advantageous before the filling root canals with bioactive sealers.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 2001년도 International Conference CALS/EC KOREA
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• pp.577-590
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• 2001

Designing Seal Windows System ㆍReduced (by a factor of at least 10) the time for evaluating each design alternative ㆍIncreased quality by 20％ (measured as the number of errors that are caught before they propagate) ㆍFound and corrected errors prior to production with an estimated $1-2 million in annual savings in warranty costs ㆍCaptured the state of a design, particularly the parameters that were used to make decisions ㆍEliminated geographic and temporal obstacles ㆍDecreased wasted time caused by slow communication paths(omitted)

• Restorative Dentistry and Endodontics
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• 제14권1호
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• pp.97-105
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• 1989

This study was conducted to evaluate and compare the apical leakage among the retrograde filling materials; retrograde filling with non-zinc amalgam, cavity varnish and non-zinc amalgam, z.o.e cement, Glass Ionomer cement, scotch bond and silux. Sixty single rooted teeth were divided into six groups and each tooth was individually prepared for its particular group. The specimens were incubated at $37^{\circ}C$ for 24 hrs and then were infiltrated by 2% methylene blue for 7 days. Apical leakage was evaluated by measuring the degree of dye penetration between the filling material and the canal wall. The results were as follows: 1. The scotch bond and silux group showed the least amount of apical leakage and the control group showed the greatest amount of apical leakage. 2. The groups retrofilled with cavity varnish and amalgam, glass-Ionomer cement, scotch bond and silux showed significantly good apical seal than control group. 3. The groups retrofilled with glass Ionomer cement, scotchbond and silux showed significantly good apical seal than the groups retrofilled with Amalgam and Zinc oxide eugenol cement.

• 한국정보통신학회논문지
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• 제11권1호
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• pp.124-130
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• 2007

RFID는 항만 물류의 효율성을 높일 수 있는 기술로 주목을 받고 있다. 특히 컨테이너 용 e-Seal 등 능동형 RFID 기술에 대한 관심이 높다. 그런데 능동형 RFID 뿐 아니라 수동형 RFID나 전통적인 바코드 시스템을 복합사용하면 전체 항만 물류 처리과정의 효율을 증대시킬 수 있다. 그러나 각 RFID 리더 및 인식 장치에 종속적인 다양한 제어 인터페이스로 인해 복합사용 환경 구축에 많은 어려움을 겪고 있다. 본 논문은 Smart Reader Interface라는 장치 독립적인 공통의 인터페이스를 통해 다양한 RFID 리더 및 인식 장치를 제어 할 수 있는 RFID 미들웨어를 설계하였다. 우리는 관련 표준, 처리의 효율성, 새로운 리더 추가에 대한 확장성 등을 주요 고려 사항으로 설계에 반영하였다. 설계 결과를 바탕으로 실제 다양한 상용 RFID 리더를 지원하도록 시스템을 구현하였다. 실험실 환경 뿐 아니라 실제 광양항 컨테이너 부두에서 실시한 실험을 통해 개발한 시스템의 실용성을 검증하였다.

• 통상정보연구
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• 제6권1호
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• pp.191-210
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• 2004

There are increasing needs for an individual or enterprise to interchange documents electronically through communication network to enhance the efficiency of business, owing to rapid process of transactions. But e-commerce encounters the problems regarding the handling the electronic documents, that is to say, deposit and proof of the electronic documents. This paper deals with Authorized Electronic Data Depot as an integrated system for processing, relaying and proving documents that. Authorized Electronic Data Depot operates as e-enabler in exchanging documents in trust among administrative agencies and a comprehensive government directory, digital government seal certification system and DNS system. Authorized Electronic Data Depot leads public and private sectors to save the paper-related costs. But the regulations concerning an authorized electronic data depot is introduced in the course of revision of Electronic Transactions Act. The purpose of this paper is to suggest some guidelines in legalizing the authorized electronic data depot.

• Elastomers and Composites
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• 제30권3호
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• pp.235-246
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• 1995

When an O-ring is installed in a high fluid pressure device, a section of the O-ring is extruded into the piston-cylinder clearance gap. Any tendency towards extrusion will induce wear in dynamic applications, leading to premature failure of the seal. In this study, the mechanism of initial extrusion of the O-ring was studied, 1.e., how much amount of the O-ring will be extruded into the clearance gap at a certain pressure. The relationship between extrusion depth and a clearance gap or fluid pressure were studied by finite element analysis (FEA). After that, Salita's experimental data were analyzed. The result is that Initial extrusion depth for an O-ring into a clearance gap was 1.11 times the product of dimensionless pressure difference $(p-p_1)/E$ and clearance gap c. The required pressure $p_1$ for zero extrusion depth was found to decrease logarithmically with increasing clearance gap.