• Journal of the Korean Electrochemical Society
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• v.27 no.3
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• pp.88-96
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• 2024

Lithium metal has garnered attention as a promising anode active material thanks to its high specific capacity, energy density, and the lowest reduction potential. However, the formation of dendrites, dendritic crystals that arise during the charge and discharge process, has posed safety and lifetime stability challenges. To resolve this, our study has introduced a novel separator design. This separator features a composite coating of vapor-grown carbon fiber, a conductive material in nanofibers, and silver. We have meticulously studied the impact of this innovative separator on the electrochemical properties of the lithium metal anode, unveiling promising results. To confirm the synergistic effect of VGCF and Ag, a separator with no surface treatment and a separator with only VGCF coated on one side were prepared and compared with the Ag-VGCF-separator. In the case of the bare separator, the Li metal surface is covered with dendrites during the initial charge and discharge process. In contrast, both the VGCF-separator and the Ag-VGCF-separator show Li precipitation inside the conductive coating layer coated on the separator surface. Additionally, the Ag-VGCF-separator showed a more uniform precipitate shape than the VGCF-separator. As a result, the Ag-VGCF-separators show improved electrochemical properties compared to the bare separators and the VGCF-separators.

• Journal of The Korean Association For Science Education
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• v.36 no.1
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• pp.167-175
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• 2016

This study aims to find out the meaning of characters used in science textbooks by analyzing the roles of the characters on the 2009 revised science textbooks and the extracted sentences and see if there are indications referable to compiling future science textbooks by finding out where the characters are efficiently used and where supplement is needed. Target textbooks among those developed for the 2009 revised elementary school science textbooks are the first and second semester of the 4th-grade. Methods used include analysis on the roles of character-containing questions using character role analysis whose illustration analysis frame is more supplemented/adjusted than those used in the foregoing studies, analysis on character-containing questions using the existing analysis frame, analysis/survey on good cases and cases needing supplement through consultation with a science education expert, two teachers, etc. The result shows that among types of character roles, motivation and material provision are more used than experiment guide, experiment, and observation results. Result of analyzing in-textbook characters by field shows that life sphere is more used than free exploration, energy, material, and earth. Result of analyzing question types shows the order of expanding, anticipatory, transferable and personal questions and there were no reminiscent and evaluative questions. Based on the result of this study, indications on how to use in-science textbook characters more efficiently and developmentally are needed.

• Fire Science and Engineering
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• v.26 no.6
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• pp.92-98
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• 2012

In this sturdy, large experimental (ISO 13785-2) was performed to analyze the building materials used in fire retardant materials for aluminum composite panel and in general properties. As a results, maximum temperature in the case of the general materials was measured in 210 seconds $1,021^{\circ}C$, the retardant materials was measured in 1,200 seconds early $1,190^{\circ}C$. The retardant material of aluminum composite panel, Fire behavior if the ignition is slow and the general materials in aluminum composite panel, fire ignition and combustion at the same time was growing rapidly. The general materials and flame-retardant material of aluminum composite panel was an obvious difference to the combustion ignition but after ignition combustion mode showed a similar pattern of the rapidly vertical spread of flame. The results of this study, in order to reduce the risk of aluminum composite panels for fire and the retardant materials used for ignition the slow should be actively encouraging. Also after the ignition, there is an urgent need to put out a fire in exterior materials for extinguishing facilities.

• Journal of Wetlands Research
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• v.17 no.1
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• pp.38-44
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• 2015

In Korea, most rainfall events occur during summer which then leads to an increasing concern regarding high influx of non-point source pollutants since the pollutant loadings from these non-point sources are very significant. In particular, the first flush of roof-harvested rainfall is said to contain the most highest concentration of nutrients and heavy metals. Accordingly, it is important to develope the possible water quality management options in treating the contaminants and considering reclaimed water reuse. The rain garden could be one of suitable alternatives in addressing this issue. In this study, the development of an effective adsorption media and its application to a lab-scale rain garden was tested to evaluate the removal rate of various nutrient and organic matter (TN, TP, CODcr), and heavy metals (Cu, Cd, Pb). Results showed that carbonized peatmoss produced at higher temperature have better adsorption capacity as compared to the one produced at a lower temperature. When the carbonized peatmoss was applied as rain garden media, the highest removal of TN, TP, and CODcr was observed compared to no carbonized peatmoss applied rain garden. Therefore, this study showed that the carbonized peatmoss would be effectively applied to the rain garden for removing nutrients and heavy metals from roof-harvested rainwater.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.196-204
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• 2020

The aim of the study is to compare the fluoride release and recharge properties of glass ionomer cements and 'alkasite'. Specimens of two glass ionomer cements (Fuji IX GP and Riva Self Cure), 'alkasite' restorative material (Cention N) and composite resin (Filtek™ Z350XT) were prepared. The fluoride release of each specimen was measured for 28 days. Thereafter, 1.23% acidulated phosphate fluoride (APF) gel was applied to experimental groups. No treatment was performed on control groups. The fluoride release was measured for additional 7 days to evaluate the fluoride recharge properties of each materials. The fluoride release was highest in Riva Self Cure, followed by Fuji IX GP, Cention N (p < 0.05). Fluoride release of Cention N was measured to be approximately 49% of Fuji IX GP's. After the application of 1.23% APF gel, increases in fluoride release were observed in Riva Self Cure, Fuji IX GP and Cention N (p < 0.05). Fluoride recharge was observed in Cention N as well as in glass ionomer cements. Further studies are required to evaluate the anti-cariogenic properties of Cention N at clinical conditions.

• Journal of Conservation Science
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• v.32 no.2
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• pp.235-247
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• 2016

Conventional imaging techniques such as ultraviolet, infrared, and X-ray are used mainly to diagnose the damaged parts of the painted cultural assets in Korea. These techniques, however, have limits in diagnosing damages of interlayer parts. We have performed and extensive study on the applicability of Terahertz(THz) analysis technique, introduced recently to this field of study on cultural properties in Korea, to diagnose painted cultural assets. The specimens, produced to imitate the damage types of Korean painted properties, were analyzed over their painting, supporting, and backing layers by terahertz pulse imaging technique. The analyzed results provided information about the cracks, the separated areas, and the separated distances between layers on the specimens. Our research, then, was extended to real painted cultural remains, Birojana Sam-shin Gwebul-do at Bongseon Temple in Namyang-ju, Korea National Treasure Number 1792, through which we have obtained 3D information about the extent and pattern of damages to the asset. These results demonstrate that terahertz 3D imaging technique has the capability of noncontact 3D diagnosis on painted cultural properties.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.44-52
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• 2017

In this paper, we propose a DFD (Digital Frequency Discriminator) design that has better frequency discrimination and a smaller size. Electronic warfare equipment can analyze different types of radar signal such as those based on Frequency, Pulse Width, Time Of Arrival, Pulse Amplitude, Angle Of Arrival and Modulation On Pulse. In order for electronic warfare equipment to analyze radar signals with a narrow pulse width (less than 100ns), they need to have a special receiver structure called IFM (Instantaneous Frequency Measurement). The DFD (Digital Frequency Discriminator) is usually used for the IFM. Because the existing DFDs are composed of separate circuit devices, they are bulky, heavy, and expensive. To remedy these shortcomings, we use a three delay line ($1{\lambda}$, $4{\lambda}$, $16{\lambda}$) in the DFD, instead of the four delay line ($1{\lambda}$, $4{\lambda}$, $16{\lambda}$, $64{\lambda}$) generally used in the existing DFDs, and apply the microwave integrated circuit method. To enhance the frequency discrimination, we detect the pulse amplitude and perform temperature correction. The proposed DFD has a frequency discrimination error of less than 1.5MHz, affording it better performance than imported DFDs.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.112-119
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• 2006

본 논문은 디지털홈서비스의 실제 이용자들에 대한 실증분석을 통해 수용에 영향을 미치는 요인들을 밝히기 위한 연구이다. 디지털홈서비스의 특성에 맞게 기술수용모형 (TAM) 을 확장. 수정된 연구모형을 개발, 가설을 설정하여 분석하였다. 외부변수로 이용자의 특성을 채택하였으며, 디지털홈서비스가 가정 내 기술임을 고려하여 신념변수로 ‘지각된 이용용이성’과 ‘지각된 즐거움’ 외에 ‘지각된 편의성’, ‘지각된 안전성’, ‘지각된 삶의 질 향상’이라는 변수를 추가하였고 종속변수로는 ‘이용행동’을 설정하였다. 205명의 실제 이용자를 대상으로 한 설문조사 중 201개의 유효표본을 분석하였고, 신뢰성과 타당성 모두 통계적으로 적합한 것으로 나타났다. AMOS 4를 이용한 구조방정식 모형분석을 통해 24개의 가설검증 결과, 13개의 가설이 채택되었다. 이용자 개인의 특성 중 경험과 교육훈련은 지각된 이용용이성에 정(+)의 영향을 미쳤으며 혁신성은 지각된 즐거움, 지각된 편의성, 지각된 안전성, 지각된 삶의 질 향상에 대하여 정(+)의 영향을 미치고 있었다. 또한 지각된 이용용이성이 다른 신념변수인 지각된 즐거움, 지각된 편의성, 지각된 안정성, 지각된 삶의 질 향상에 정의 영향을 미치고 있었다. 종속변수인 이용행동에는 지각된 즐거움과 지각된 편의성, 지각된 삶의 질 향상이 긍정적인 영향을 미치나, 지각된 이용용이성과 지각된 안전성은 영향을 미치지 않았다. 가정에서 쉽게 이용할 수 있다는 것만으로는 적극적인 이용 행동을 기대할 수 없으며, 즐거움 및 실용적인 효익들의 제공 및 이를 위한 다양한 컨텐츠와 프로그램 개발 등이 매우 중요하다는 것을 시사하고 있다.수십억원의 추가적인 이익을 실현할 것으로 분석되었다. 본 알고리즘을 확장 적용할 경우 PBUC 문제 해결을 위한 새로운 해법으로도 그 효용성이 클 것으로 예상된다.자료이기 때문에 통계적 활용의 범위가 방대하다. 특히 개인, 가구, 사업체 등 사회 활동의 주체들이 어떻게 변화하는지를 추적할 수 있는 자료를 생산함으로써 다양한 인과적 통계분석을 할 수 있다. 행정자료를 활용한 인구센서스의 이러한 특징은 국가의 교육정책, 노동정책, 복지정책 등 다양한 정책을 정확한 자료를 근거로 수립할 수 있는 기반을 제공한다(Gaasemyr, 1999). 이와 더불어 행정자료 기반의 인구센서스는 비용이 적게 드는 장점이 있다. 예를 들어 덴마크나 핀란드에서는 조사로 자료를 생산하던 때의 1/20 정도 비용으로 행정자료로 인구센서스의 모든 자료를 생산하고 있다. 특히, 최근 모든 행정자료들이 정보통신기술에 의해 데이터베이스 형태로 바뀌고, 인터넷을 근간으로 한 컴퓨터네트워크가 발달함에 따라 각 부처별로 행정을 위해 축적한 자료를 정보통신기술로 연계${cdot}$통합하면 막대한 조사비용을 들이지 않더라도 인구센서스자료를 적은 비용으로 생산할 수 있는 근간이 마련되었다. 이렇듯 행정자료 기반의 인구센서스가 많은 장점을 가졌지만, 그렇다고 모든 국가가 당장 행정자료로 인구센서스를 대체할 수 있는 것은 아니다. 행정자료로 인구센서스통계를 생산하기 위해서는 각 행정부서별로 사용하는 행정자료들을 연계${cdot}$통합할 수 있도록 국가사회전반에 걸쳐 행정 체제가 갖추어져야 하기 때문이다. 특히 모든 국민 개개인에 관한 기본정보, 개인들이 거주하며

• Information Systems Review
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• v.18 no.1
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• pp.79-103
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• 2016

The Korean Army has to construct a system that will enable it to cope immediately with the flexible military relationships in Northeast Asia by systematizing and improving the efficiency of operations. These improvements include building a smart and strong army, concentrating on cost-effective combat skills, maximizing the utilization of private resources, and establishing a military structure based on information and technology. Accordingly, this study proposes solutions to solve the problems affecting the success of outsourcing in the defense industry. Unlike outsourcing in other government ministries, outsourcing in the national defense sector may be unrealistic because this strategy is related to the renovation project of the Ministry of the National Defense. In general, the objective of outsourcing in the defense industry, similar to other businesses, is to improve efficiency and not to reduce troops and national defense budget. Several factors, such as identification and security guarantee, risk reduction, cost saving, quality improvement, the reliability of enterprise, and professional technology, are necessary to ensure outsourcing success in the national defense sector. In terms of effectiveness, the improvement in service quality significantly influences outsourcing success in the national defense sector. Eventually, the national defense forces must be strengthened to prevent the provocative actions of North Korea and other threats by improving identification, sense of national security, and quality unlike the current outsourcing of the government, as well as emulating German GEBB or PMC, which utilizes social capital.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.533-540
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• 1999

We observed that the thick outer bark layer of Quercus variabilis hindered oak longicorn beetle (Moechotypa diphysis) from laying its eggs in inner bark (secondary phloem tissues). The outer bark thickness of Q. variabilis was average of 7.4mm, while those of Q. mongolica. Q. serrata and Q. acutissima were average of 1.1mm, 1.3mm and 2.0mm, respectively. Inner bark thickness was 4.8mm in Q. acutissima and 3.6-3.9mm in the other oak species. The outer shape of ovipositional holes on the bark by the longicorn beetle was $8-12mm{\times}6-8mm$ wide oval in Q. variabilis, whereas $5-9mm{\times}1-5mm$ narrow fusiform in the other oak species. Oak longicorn beetle drilled average of three ovipositional holes per a 1.2m-long log in a few Q. variabilis logs and its ovipositional rate was 15%. Compared to this, the longicorn beetle preferred Q. mongolica. All the 32 investigated logs of this oak species were drilled to have 20 ovipositional holes per a log and ovipositional rate was 56%. One third of the eggs laid already hatched in early June to damage the inner bark. It seems that oak longicorn beetle prefers oak species with smooth, thin and stable outer bark surface.