• 한국환경보건학회지
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• 제44권5호
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• pp.421-432
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• 2018

Objectives: In this study, we started to develop an indoor garden integrated IoT solution based on IAQ (indoor air quality) and interconnection with an environmental database for smart management of indoor gardens. The purpose of this study was to develop and apply an integrated solution for customized air purification from an indoor garden through big data analysis using IoT technology. Methods: An IoT-based IAQ monitoring system was established in three households within a new apartment building. Based on real-time and long-term data collected, $PM_{2.5}$, $CO_2$, temperature, and humidity changes were compared to those of indoor garden applications and the analyzed results were indexed. Results As a result of the installation, all three households had no results exceeding the standard for indoor air pollution on average $PM_{2.5}$ and $CO_2$ indices. In the case of indoor garden installation, the IAQ index increased to the "Good" section after the installation, and readings in the "Bad" section shown before the installation disappeared. The comfort index also did not dip into the "Uncomfortable" section, where it had been preinstallation, and significantly lowered the average score from "Uncomfortable for sensitive groups" to "Good". Overall, the IAQ composite index for the generation of installations decreased the "Good" interval, but "Bad" did not appear. Conclusions In this study on developing an integrated solution for IAQ based on IoT indoor gardens, big data was analyzed to determine IAQ and comfort indexes and an IAQ composite index. Through this process, it became understood that it is necessary to monitor IAQ based on IoT.

• 한국환경과학회지
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• 제25권11호
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• pp.1467-1474
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• 2016

In response to the water shortage problem, continued attempts are being made to secure consistent and reliable water sources. Among various solutions to this problem, wastewater effluent is an easy way to secure the necessary supply, since its annual output is consistent. Furthermore, wastewater effluent has the advantage of being able to serve various purposes, such as cleaning, sprinkling, landscaping, river management, irrigation, and industrial applications. Therefore, this study presents the possible use of reclaimed industrial wastewater treated with Birm filters and a UF membrane, along with an analysis on membrane fouling. The preprocessing stage, part of the reclamation process, used Birm filters to minimize membrane fouling. Since this study did not consider heavy metal levels in the treated water, the analyses did not include the criterion for irrigation water quality. However, the wastewater reclaimed by using Birm filters and a UF membrane met every other requirement for reclaimed water quality standards. This indicated that the treated water could be used for cleaning, channel flow for maintenance, recreational purposes, and industrial applications. The analysis on the fouling of the Birm filter and UF membrane required the study of the composition and recovery rate of the membrane. According to SEM and EDX analyses of the UF membrane, carbon and oxygen ion composition amounted to approximately 57%, whereas inorganic matter was not detected. Furthermore, the difference in the recovery rates of the distressed membrane between acidic and alkaline cleaning was more than ~78%, which indicated that organic rather than inorganic matter contributed to membrane fouling.

• 자원환경지질
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• 제56권3호
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• pp.217-227
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• 2023

결정질 탄산칼슘(CaCO₃)은 방해석(calcite), 아라고나이트(aragonite), 바테라이트(vaterite) 세 동질이상체로 다양한 지질 및 수중 환경에서 흔하게 발생한다. 또한, 탄산칼슘 광물은 기능성 재료로 사용될 수 있어 공학적인 용도로 많은 관심을 받고 있다. 자연계와 공학적인 세팅에서 생성되는 탄산칼슘의 형성 및 그 반응을 이해하고 다양한 생약 및 생의학 물질로 활용하기 위한 탄산칼슘 광물 형성에 대한 실험적 모사 방법(즉, 합성법)에 관한 연구가 활발히 진행되어왔다. 합성법에서 물을 용매로 탄산칼슘 결정 형성을 유도하는 방식(수용액-기반 합성법)은 자연계에서 발생하는 탄산염광물 형성 조건과 유사하므로 지질학 연구에서도 그 의미성이 매우 크다. 본 리뷰 논문에서는 문헌에서 보고되는 수용액-기반 탄산칼슘 합성법을 탄산칼슘 동질이상체 별로 분류한다. 또한, 여러 합성법에서 나타나는 결정의 형상 및 구조적 특성을 동질이상체 별로 분류하고 결정화 메커니즘을 통해 그 특성들을 토론하고자 한다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2008년도 추계학술발표대회 및 제15회 신소재 심포지엄
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• pp.3.2-3.2
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• 2008

• 한국독성학회:학술대회논문집
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• 한국독성학회 2000년도 국제심포지움 및 추계학술대회
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• pp.71-163
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• 2000

• 교통기술과정책
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• 제8권1호
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• pp.41-50
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• 2011

• Smart Structures and Systems
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• 제4권3호
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• pp.367-389
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• 2008

Shape Memory Alloys (SMAs) are unique materials with a paramount potential for various applications in bridges. The novelty of this material lies in its ability to undergo large deformations and return to its undeformed shape through stress removal (superelasticity) or heating (shape memory effect). In particular, Ni-Ti alloys have distinct thermomechanical properties including superelasticity, shape memory effect, and hysteretic damping. SMA along with sensing devices can be effectively used to construct smart Reinforced Concrete (RC) bridges that can detect and repair damage, and adapt to changes in the loading conditions. SMA can also be used to retrofit existing deficient bridges. This includes the use of external post-tensioning, dampers, isolators and/or restrainers. This paper critically examines the fundamental characteristics of SMA and available sensing devices emphasizing the factors that control their properties. Existing SMA models are discussed and the application of one of the models to analyze a bridge pier is presented. SMA applications in the construction of smart bridge structures are discussed. Future trends and methods to achieve smart bridges are also proposed.

• 대한지구과학교육학회지
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• 제3권1호
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• pp.9-17
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• 2010

This study was carried out to examine the tendency about the relative importance of STS education of the 6th and 7th primary science curriculum. The results of the research are as follows. Primary science textbooks in the 6th curriculum, average 13.3% of the total pages was assigned to STS contents but it is increased to 24.2% in the science textbooks of the 7th curriculum. STS constituents of the 6th primary science textbooks come out orderly applications of scientific knowledge(47.1%), relevance of a community(40%), social problems and issues(11.8%). Of the 7th science textbooks, the contents about applications of scientific knowledge amount to 67.1% of the total STS constituent and relevance of a community(32.2%) rank behind it. The contents of other components are not enough. The 6th science textbooks contents about the effect of technological development amount to 35.3% of the total STS subject area, and environmental quality(20.0%), natural resource(15.2%), energy(11.8%), sociology of science(11.8%) ranks behind it. In the 7th science textbooks ranking is the effect of technological development(42.3%), natural resource(17.3%), energy(12.5%), sociology of science(12.5%), environmental quality(20.0%). There are few contents about population, human engineering and space research and national defense in the science textbooks.

• 한국실내디자인학회논문집
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• 제18권6호
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• pp.229-238
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• 2009

Currently, subway is becoming a major part of transportation and living environment in large cities such as Seoul or Hong Kong. As the numbers of subway lines and stations increase, visual cues indicating places are needed for users with various destinations, and environmental colors as well as line colors can be expected as effective informations for easy wayfinding. The purpose of this study is to understand the current color applications in terms of creating regional differentiation and informing subway lines in the transfer stations of Seoul and Hong Kong, by field investigation. The investigation has been proceed on 24 transfer stations from February to April, 2009 by taking photos and measuring environmental colors using Minolta spectrophotometer CM-2600d. As a result, regional differentiation in color application appeared generally low in both Seoul and Hong Kong but various 'hues' differing each station are used in Hong Kong, compared to limited use of 'hues' in Seoul, In terms of 'value', the rate of Seoul appeared lightly higher than that of Hong Kong, and the use of medium high rate of 'saturation' of main and secondary colors are shown as a remarkable character of Hong Kong.

• 한국표면공학회지
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• 제54권6호
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• pp.331-339
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• 2021

Environmental barrier coatings(EBCs) are applied to the SiC/SiC ceramic matrix composites(CMCs) in order to protect CMCs from being corroded with water vapor by combustion gas in gas turbine engines. Ytterbium silicates, such as ytterbium monosilicate and ytterbium disilicate, are ones of the candidate materials for EBCs due to their excellent resistance to water vapor corrosion as well as thermal-expansion match with SiC. In this study, ytterbium silicates are fabricated with 2-step solid-state synthesis targeting ytterbium disilicate. After synthesizing ytterbium monosilicate, the mixtures of ytterbium monosilicate and SiO₂ are heat-treated and densified by using pressureless sintering or hot pressing with a variety of heating conditions. The phase formation, thermal expansion, and oxidation behavior are examined with fabricated specimens. The final densified bodies are found to be composites between ytterbium monosilicate and ytterbium disilicate with different ratios, which results in 4.43 to 6.72×10^-6/K range of coefficients of thermal expansion. The probability of these ytterbium silicates for EBC applications is also discussed.