• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.229-230
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• 2010

The Carbonation, one of the main deterioration factors of concrete, reduces capacity of members with providing rebar corrosion environment. Consequently it suggested standards of all countries of world, carbonation depth prediction equation of respective researchers and time to rebar corrosion initiation. As a result of carbonation depth prediction equation calculation, difference of time to rebar corrosion initiation is 149 years and difference of carbonation depth prediction equation is 162 years when water cement ratio is 50%. So a study on rebar corrosion with carbonation depth will need existing reliable data and verifications by experiment.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.607-617
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• 2023

This study aims to analyze whether the performance of the fire extinguisher meets the criteria for the apparent specific gravity property test by calculating the change in internal pressure and the use period of the fire extinguisher as a new one with 5 years, recycled one with 5 years, a new one with 10 years, and a new one with 13 years, respectively. As a result of the experiment, when the internal pressure of the fire extinguisher was 0%, the first, second, and third arithmetic mean analysis of the dry chemical extinguisher according to the use period was found to be condemned. When the internal pressure of the fire extinguisher was 50%, it was measured as 130 ml in sample 12-08-new and analyzed as unsuitable. Also, sample 09-09-new of a new dry chemical extinguisher with 13 elapsed years measured 145ml, which was found inappropriate. All other dry chemical extinguishers were analyzed to be suitable. All were noted suitable when having normal internal pressure of the fire extinguisher, except for sample 09-06 of a new dry chemical extinguisher with 13 elapsed years, which was determined to be unsuitable caused by measuring as 131 ml for experimental value. As a result of experiments, some of the apparent specific gravity tests of dry chemical extinguishers from 10 years to 13 years have found that they are unsuitable for the performance of the fire extinguishers due to the massive phenomenon. Accordingly, it is necessary to reduce the endurance period of dry chemical extinguishers from 10 years to 7 years.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.495-500
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• 2001

After the completion of an apartment housing project, deterioration of building materials will commence over time. Building maintenance consists of short-time and long-term repair projects. A long-term repair plan for organized maintenance management should be developed and implemented to maintain the longevity of the building. When forming such a plan, one should carefully predict when each part of the building will need repairs and how often subsequent repairs of each part will occur. The plan should be based on these predictions. Many apartment buildings in Korea have poor long-term maintenance management plans. This is because many of these plans are developed as mere legal formalities rather than as serious attempts to maintain the longevity of buildings. In this study, the materials used in the construction of each part of an apartment building we selected are taken into account to predict when the repairs will be required and how frequently subsequent repairs will be required. Furthermore, We suggest a long-term maintenance management plan for elongation so that apartment house managers can use to periodically check, diagnose, and replace old or malfunctioning parts using a web-based maintenance calender.

• Journal of the KSME
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• v.33 no.11
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• pp.942-950
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• 1993

이 글에서는 자동차용 에어컨의 냉매 규제에 따른 대체냉매의 적용시 에어컨의 성능 변화를 이 론적으로 예측하여 보고, 냉매의 대체에 따른 응축기의 변경에 의한 성능 특성을 실험 결과로 설명하였다. 기존의 응축기(SPC)를 SCC로 교체함으로써 대체냉매를 사용하는 시스템에서 열전 달성능의 향상을 꾀할 수 있었다. 자동차용 에어컨에서 냉매의 교체에 따라 변경이 예상되는 부품으로는 응축기를 비롯하여 증발기, 팽창밸브, 수액기건조제, 압력스위치, 배관호스류, 압축기 압축기오일, 팬모터 등이 될 수 있다. 이러한 요소부품의 변경을 위해 연구개발되어야 할 기술 로는 먼저 운전 및 성능을 고려한 각 부품의 설계기술과 제작기술의 개발이 필요하다. 특히 자 동차의 내구연한의 확장에 따른 에어컨의 내구성 및 신뢰성의 문제는 지속적으로 연구되어야 할 것이다.

• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.508-516
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• 2012

The lifespan of a rolling stock is limited to 25 years by the urban railway law. But it can be extended to 40 years by conducting the regular safety test. This gives additional 15 years of lifespan. In Seoul Metro, Many of the rolling stocks were already replaced with new types in 1996 and 2008. New type - VVVF rolling stocks have better safety, maintainability, durability than old types. For this reason, it is desirable to extend the lifespan of new type-rolling stocks. In this paper, we investigated the economical lifespan using LCC (Life Cycle Cost) analysis. This study shows that the economical lifespan comes out 41 years when extra 10% cost has been considered after 25 years of the train service and 46 years when extra 10% cost not considered.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.307-314
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• 2003

해양콘크리트 구조물의 내구성에 가장 큰 영향은 미치는 요인 중의 하나가 염소 이온의 침투에 의한 철근부식이다. 염소이온이 콘크리트 구조물 내부로 확산되어 철근이 부식하게 되면 철근의 부피팽창으로 콘크리트 덮개에 균열이 발생하고 철근의 단면적도 줄어들게 된다. 따라서, 구조물은 사용연한을 채우지 못 하고 붕괴되거나 사용성에 큰 문제가 발생하게 된다. (중략)

• The Journal of the Korean dental association
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• v.25 no.8 s.219
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• pp.735-739
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• 1987

implant라는 것은 생리학적으로 생체에 있어서 이물이라는것을 인식해야 한다. 또 그 일부를 상부구조물을 제작하기 위하여 구강내에 노출시킴으로써 연조직과의 접촉부위가 감염으로 염증상태를 지속하고 있다. 그뿐아니라 저작시에 교합압에 의한 위격으로 골내에 여러 가지 변화를 일으킨다. 이와같이 생체내에 이물를 implant 하였을 때 생기는 반응은 생체의 방어기전으로서 염증을 일으키는데 이 염증의 진도에 따라 동화, 흡수, 배제중의 어느 하나로 결말짓게 된다. 따라서 implant를 시술하였을때 생기는 조직의 반응을 최소한으로 감소하기 위한 생물학적 적응조건으로서 재료, 약물, 기구, 시술방법 등을 잘 선택하는 것이 implant의 임상응용에 요절이 되는것이다. implant의 종류는 실로 다양다종이다. 그러나 어떤 implant와 시술방법을 선택하든지 악골에 접착, 또는 식위하여 견고하게 장착되어 그 implant된 자체를 통하여 가장 천연치에 가까운 기능을 얻는것이 implant의 시술목적이다. 임상의가 implant를 시술하면서 이것이 과연 성공할것인가? 즉 저작효율과 내구연한이 얼마나 갈것인가 우려하지 않을수 없다. 그러므로 그 우려를 덜고 성공으로 이끄는 임상상의 문제점을 찾아 논하기로 한다.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.293-300
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• 2012

This study was to investigate the unsuitable rate of the storage facilities, the changes in corrosion process over time after installation according to the status, the time to install the facilities, years elapsed after facilities installation, inspection of methods and motivation, and so on, based on the results of the inspection at the petroleum storage facilities conducted by domestic soil-relate specialized agency to derive optimal management plans which meet the status of soil contamination facilities. The results showed that the facilities more than 5 years after the initial leak test at the time of the installation need to be inspected periodically by considering costs of leak test and remediation of polluted soil. The inspection period can be decided by cost and leak test methods showing discrepancies for the results obtained from individual test whether it was direct or indirect. To compensate these matters, we suggested that the direct inspection method on regular schedule is recommended. On the other hand, the inspection can be voluntarily completed to ease burden of the results by inspection or equivalent level to this inspection method. Also, it may need improved construction supervision and performance test system to minimize the occurrence of the nature defects in installing the facilities as well as the upgrade program for the facilities during intervals of inspection period.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.633-636
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• 2008

Concrete structures are occur many various deteriorations in the course of time and many efforts have progressed to improve on performance of concrete. The purpose of this study is to evaluate the durability of latex modified mortar in order to repair concrete structure which are happened deterioration. In this study, we tested plastic shrinkage, drying shirnkage, repeated freezing and thawing, permeability and resistance of chemical solution. Latex modified mortar and two kinds of sprayed polymer mortar used on durability test. As a result of test, latex modified repair mortar was exhibited durablilty improvement compared to the conventional sprayed polymer mortars. It is judged the fact that latex modified mortar have no problem in site application but additionally many research will be necessary.

• Magazine of the Korea Concrete Institute
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• v.8 no.5
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• pp.201-209
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• 1996

Recently, large scale concrete structures exposed to severe environment are increasingly built in various locations. The corrosion may severely affect the durability and service life of such a concrete structure. It is, therefore, necessary to develop durable concrete to enhance the corrosion resistance. The corrosion resistance of concrete can be identified through accelerated corrosion test. The purpose of the present paper is, therefore, to devise a reasonable and accurate method to predict the amount of corrosion of reinforcing steels. The proposed method which is basically based on the concept of Faraday's Law, determines the corroded amount of a rebar according to accelerated corrosion time. The corrosion is accelerated by employing the potentiometric corrosion test arrangement. The effects of admixtures in concrete including fly ash and silica fume have been also studied to explore the relative corrosion resistance of concrete.