• Corrosion Science and Technology
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• 제3권2호
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• pp.39-46
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• 2004

Development and application of structural health monitoring system in Korea have become active since the early 1990's. In earlier applications, health monitoring systems were installed in several existing bridges in order to collect initial field data by full scale load capacity test for design verification and subsequently monitor long-term performance and durability of the bridge as part of an inspection and maintenance program. Recently, modem and integrated monitoring systems have been introduced in most of the newly constructed long-span bridges since the design stage. This paper outlines the progresses and applications of monitoring systems in Korea for both existing and newly constructed bridges and describes their aims and characteristics.

• 한국건설순환자원학회논문집
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• 제2권4호
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• pp.307-313
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• 2014

부식촉진시험의 가장 확실하고 신뢰성이 높은 방법은 해양폭로 시험장에 직접 폭로시켜 철근부식모니터링을 실시하는 방법이지만 장기간이 소요되는 단점이 있다. 그래서 이를 대체하는 수단으로 많은 연구들이 진행되어 왔다. 하지만 부식촉진시험이 폭로환경의 어느 정도 기간에 상응하느냐는 상관성에 대한 규정은 정해져 있지 않은 상황이다. 본 논문에서는 간만대, 침지내 환경을 재현한 철근부식촉진시험과 장기폭로시험을 실시하였다. 환경조건을 변수로 시험을 실시하였으며, 반전지전위법을 통한 철근부식 모니터링을 실시하였다. 부식촉진 시험결과 시험조건 별 상대부식개시시점 도출을 할 수 있었으며, 내구성 해석 프로그램인 Life365와 염화물적정시험을 통해 염화물침투해석을 실시하였다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제23권2호
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• pp.121-131
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• 2020

Purpose: To determine the long-term efficacy of the anti-tumor necrosis factor (TNF) agents, infliximab (IFX) and adalimumab (ADA), in pediatric luminal Crohn's disease (CD) by performing a systematic literature review. Methods: An electronic search was performed in Medline, Embase, and the Cochrane Library from inception to September 26, 2019. Eligible studies were cohort studies with observation periods that exceeded 1 year. Studies that reported time-to-event analyses were included. Events were defined as discontinuation of anti-TNF therapy for secondary loss of response. We extracted the probabilities of continuing anti-TNF therapy 1, 2, and 3 years after initiation. Results: In total, 2,464 papers were screened, 94 were selected for full text review, and 13 studies (11 on IFX, 2 on ADA) met our eligibility criteria for inclusion. After 1 year, 83-97% of patients were still receiving IFX therapy. After 2 and 3 years the probability of continuing IFX therapy decreased to 67-91% and 61-85%, respectively. In total, 5 of the 11 studies subgrouped by concomitant medication consistently showed that the probabilities of continuing IFX therapy in patients with prolonged immunomodulator use were higher than those in patients on IFX monotherapy. Conclusion: This review of real-world evidence studies confirms the long-term therapeutic benefit of IFX therapy in diverse cohorts of children with luminal CD. Moreover, it supports the view that combination therapy with an immunomodulator prolongs the durability of IFX therapy in patients who previously failed to recover following first-line therapy. The limited number of time-to-event studies in patients on ADA prevented us from drawing definite conclusions about its long-term efficacy.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.203-206
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• 1999

An experimental study is carried out to investigate the characteristics of concrete containing high volume fly ash. The compressive and tensile strength of fly ash concrete is slightly lower than those of ordinary concrete between 7and 28 days, however, the long-term compressive strength is significantly higher at 180 days. In durability, the high volume fly ash concretes are generally higher resistance of freeze and thaw and lowe chloride penetration, however, the depth of carbonation is increased with increasing fly ash content.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 합동춘계학술대회 논문집 전기물성,응용부문
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• pp.133-134
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• 2008

This paper describes a testing method to assess the reliability of the epoxy bushing used for the vacuum circuit breaker(VCB). Especially, in order to show the long-term durability of epoxy bushing in a short testing duration, the extremely accelerated electric stress applying test plan was adopted.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.171-176
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• 1995

In recent years, Hith Performance Concrete has attracted world wide attention for its workability, strength and long-term durability. A field test was conducted to confirm the properties of high performance Concrete in situconditions. This paper describes the concrete materials, mix proportions, fresh state properties, some aspects of placability and qualty control results for field test. From the result, it was found that it is possible to produce High Performance Concrete with self-compactable and high strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.225-226
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• 2009

Day by day, concrete buildings and structure became high-rising and magnificently vast scheduled, as contributed from the development of improved equipments that suitable to specific construction works and high qualitied Material, the durability of the concrete was highly improved. The temporary elastic reduction occur at vertical members such as walls and columns under vertical loads. Specially, inelastic reduction such as creep and shrinkage occur long termly with elastic one in case of reinforced concrete members. Generally, creep and shrinkage depend on time and this is affected by concrete strength, concrete type, member size, steel ratio, and relative humidity. And elastic reduction rely on time, too because concrete is loaded before revelation of perfect strength in terms of construction conditions. So, tests on mechanical properties of concrete certainly need in order to apply to construction by forecasting an amount of reduction caused by the complex factors. Therefore, in this study the tests on creep, shrinkage are carried out to offer basic data for predicting an amount of long-term Properties at the concrete columns of an object structure, and results of the tests are described.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.113-117
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• 2009

Fly ash (called FA hereafter) that results from thermal power plants is a long-term strength improving substance with reactivity to pozzolan and has been used for long. However, large amount of FA shows many advantages such as reduction of hydratio energy, long-term improvement in strength and economic feasibility and also has difficulties from reduction in initial strength and durability. In a preceding study, fine particle cement was applied to test the effects on initial strength. Therefore in this study, the effects of fine particle cement on the quality of FA concrete were reviewed. The results can be summarized as follows. Liquidity was increased by the most at FC substitution ratio of 15%. Air capacity was reduced according to increasing substitution ratio of FA and FC. Compressive strength showed high strength expression at all ages when FC was substituted at 45%. Synthesizing the above results, appropriate mixing of FC in FA concrete can improve liquidity, reduce unit quantity and show improvement in strength. In particular, mixed use of FC seems effective in improving early quality of concrete.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2004년도 추계총회 및 연구발표회 초록집
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• pp.89.3-89.3
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• 2004

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 추계총회 및 연구발표회 초록집
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• pp.62.2-62
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• 2003