• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.32.2-32.2
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• 2009

21세기의 IT 및 NT를 선두 하게 될 나노소자의개발은 10년 전부터 아주 활발히 연구되고 있다. 최근, 이러한 나노소자의 연구 가운데 주목할 만한 물질이 ZnO 이다. ZnO를 기반으로 한 나노구조는 여러 성장 법으로 성장이 용이하고, 그 물리적, 광학적 특성이 우수하여 광 전소자 응용에 크게 이바지할 물질로 관심을 끌고 있다. 이 가운데 나노선은 소자제작이 용이해 가장 많이 이용되고 있다. 나노선을기반으로 한 소자제작은 bottom-up 공정을 지향하고 있지만, 아직은 top-down 방식이 소자제작의 주류를 이루고 있다. 특히, 나노선 FET 소자제작 시에는 여전히 top-down이 사용되고 있으며, 채널로 사용되는 나노선의 어레이공정은 소자제작 시 가장 큰 어려움으로 대두되고 있다. 하지만, 이러한나노선의 수평 어레이 공정을 감소시킬 구조로 기판에 수평으로 배열된 나노월 구조가 제안되고 있다. 나노월구조는 어레이 공정 수를 크게 감소시켜 생산가격 면에서 큰 이점을 가져올 것으로 생각된다. 하지만, 이러한 ZnO 나노월은 GaN 기판에 한정하여 성장되고 있으며, 일부 Si 기판 위에 성장할지라도나노 사이즈가 아닌 마이크로 사이즈의 거친 표면을 가지는 박막구조로 보고되었다. 때문에, 가격적으로 비싸고 응용성이 제한적인 비전도성 기판을 대신하여, 가격이 저렴하고 응용성이 넓은 Si과 같은 전도성 기판에 나노월 구조를 성장하는 기술이 요구되고 있다. 본 연구에서는 Mg의 도입으로 자발적으로 형성된 비정질 MgO층 위에 상 분리된 MZO 비정질-단결정 층들을 이용하여 어떠한 기판에서도 나노월 구조가 성장할 수 있는 기반 기술을 소개한다.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.2
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• pp.1-13
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• 2020

This study closely analyzed poems and paintings related to Beijing-Palgyeong, as well as ancient maps and ancient writings. Through the study, people who read this study can consider, Beijing-Palgyeong's the process of changing times, changing landscape perception, physical and symbolic landscape elements, structural analysis, national management relationships, and finally how it was localized as symbolic place. The view point of the Beijing-Palgyeong is distributed in four places, one outside and one inside the city. Outside of the capital city of Beijing-Palgyeong were concentrated in Seosan(西山) where the resting place of the emperor and the center of the landscape view of Beijing. The view point of Beijing-Palgyeong inside the capital city is located in two places in the royal palace's Imperial Garden and in two villages around the fortress. In other words, Beijing-Palgyeong was selected as a place closely related to the imperial family, emperor, and royal palace from the time of its initial creation. Since then, many scholars, including the emperor, have used it for national management through Won(元), Ming and Qing Dynasty, and it have become more and more characteristic of 'The capital city of eight scenic views'. The two places inside the capital city praised the Gods and Emperors in the same way. Outside the capital city, the two sites depict the comfortable lives of the people who are governed by the emperor and depicting the village landscape around the city. In the end, it can be seen that most of the Beijing-Palgyeong are related to imperial palaces and emperors. If you look at the physical landscape of Beijing-Palgyeong by element, it mainly contains the contents of national management and the emperor's eulogy. Qianlong Emperor established the Beijing-Palgyeong in 1751 through the construction of a monument. A four-character on the front of the monument, and inscribed with a seven-word written by the person on the back. It can be said that Qianlong Emperor's Beijing-Palgyeong were intended to show off the results of Manchurian rule through the material symbol of the monument. Beijing-Palgyeong have been transformed into a landmark, and modern people use it as an indicator of the Beijing-Palgyeong.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.237.2-237.2
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• 2011

SAW-ED를 이용하는 박막공정 기술을 통하여 나노레벨의 SWCNT 와 PEDOT의 thin film 및 hybrid화된 film구조를 얻을 수 있었다. SWCNT와 전도성고분자와의 hybridization을 통해 균일상의 표면 morphology를 갖는 고전도성 투명 필름을 제작하고, 이들의 전기광학적 성질을 확인하였다. SAW-ED를 이용하는 박막공정 기술은 나노입자 및 나노구조물의 박막화 패턴화를 포함하는 새로운 deposition 기술로서의 응용성을 가지고 있으며, 본 연구에서는 SWCNT와 전도성고분자를 이용하여 이를 확인하였다.

• Journal of Korean Society of Forest Science
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• v.85 no.1
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• pp.120-129
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• 1996

This study was carried out to investigate the hydraulic architecture such as relative hydraulic conductivity, Leaf specific conductivity(LSC), Huber value, Specific conductivity of the stem, branch and Junctions of stem-to-branch in Quercus mongolica trees. The hydraulic architecture of various hydraulic conductivities of stem and branch was described. The results obtained were summarized as follows : 1. The range of relative hydraulic conductivity was $2.5526{\times}10^{-12}$ to $1.2260{\times}10^{-10}m^2$ in stems, $1.6279{\times}10^{-11}$ to $6.8378{\times}10^{-11}m^2$ in branches. The relative hydraulic conductivities increased with decreasing diameter of stem and branch. The relative hydraulic conductivity of one-year-old terminal shoots were two times greater than that of the lateral shoots. 2. LSC value was larger at the top than at the base in stem. LSC is much smaller in branches than in stem ; especially smallest at branching part. 3. Hydraulic conductivities of the branching part appeared the different values with the 4 type and 4 type. Relative hydraulic conductivity, LSC, Specific conductivity and mean vessel diameter in type branching part were larger in stem than in branch part, but not found in the branching part of Y type. 4. LSC and Specific conductivity of stem increased with decreasing diameter, but Huber value slowly increased with decreasing diameter ; especially highest at less than 1cm diameter. 5. LSC, Huber value, and mean diameter of vessels were larger at 1-year-old leader shoots than at lateral shoots. 6. The mean vessel diameter in various parts of a tree decreased with decreasing diameter of stem, but the number of vessels per unit area($mm^{-2}$) increased reversely. Mean vessel diameter in stem decreased sharply at earlywood and slowly at latewood with decreasing diameter of stem.

• Korean Journal of Materials Research
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• v.5 no.7
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• pp.786-793
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• 1995

Ag-doped $Y_1$Ba$_2$Cu$_3$O$_{7-y}$ samples have been prepared by solid state reaction. High-Tc super conductivity, microstructure and mechanical property of the Ag-doped $Y_1$Ba$_2$Cu$_3$O$_{7-y}$ samples have been studied. As the Ag content increased, the grain size of $Y_1$Ba$_2$Cu$_3$O$_{7-y}$, increased and connectivity between the grains was improved, and the sample becomed denser and harder than the undoped. From the result, it is concluded that Ag addition reduced weak link and weak coupling between grains and led to the strong coupling. Furthermore, the anisotropy of crytstal structure was decreased and thermal stability, mechanical property of $Y_1$Ba$_2$Cu$_3$O$_{7-y}$-Ag were improved.mproved.

• Composites Research
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• v.35 no.6
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• pp.431-438
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• 2022

Efficient heat dissipation in current electronics is crucial to ensure the best performance and lifespan of the devices along with the users' safety. Materials with high thermal conductivity are often used to dissipate the generated heat from the electronics to the surroundings. For this purpose, polymer composites have been attracted much attention as they possess advantages rooted from both polymer matrix and thermally conductive filler. In order to meet the thermal conductivity required by relevant industries, composites with high filler loadings (i.e., >60 vol%) have been fabricated. At such high filler loadings, however, composites lose benefits originated from the polymer matrix. To achieve high thermal conductivity at a relatively low filler loading, therefore, constructing the heat conduction pathway by controlling filler structure within the composites may represent a judicious strategy. To this end, this review introduces several recent approaches to manufacturing heat dissipating materials with high thermal conductivity by manipulating thermally conductive filler structures in polymer composites.

• Korean Journal of Heritage: History & Science
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• v.45 no.2
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• pp.38-53
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• 2012

The transition process of the Balhae's capital system(都城制度) is a step-by-step marker of the completion of the state's governing system(支配體制). The most important subject in investigating the formation process of the capital of Balhae is Shanggyeongsheng(上京城). That's because Shanggyeongsheng(上京城) with a threefold-castle structure(三重城) of royal palace(宮城)-internal castle(內城)-external castle(外城) in the side-to-side checkerboard type symmetrical structure has the most paradigmatic castle structure not only in Balhae but also in East Asia. Despite the fact that such structure of Shanggyeongsheng(上京城) has a lot of similarities in the type with Sudangchangansheng(上京城) in Chungwon, scholars were skeptical that it had the same structure with Sudangchangansheng(上京城) at the time when transferring the capital. If we review the result of excavation of Shanggyeongsheng(上京城) and the findings of the senior scholars, it can be understood that Shanggyeongsheng(上京城) has not only the structure of Sudangchangansheng(上京城) but also accepted the principle of construction projected in it. It was confirmed that there is room for reconsideration on the theory of step-by-step construction(段階別築造) which was claimed based on the point that the construction like today's construction was impossible with the level of national power at that time in that the layers whose difference in construction time between the place No. 2, the central point of the royal palace, and the palaces No. 3~5 could be found were not identified, in that the whole Shanggyeongsheng(上京城) was planned by the same standard scale and finally in that there is a good possibility of accepting Samjoje(三朝制). The Shanggyeongsheng(上京城) is the result of the construction conducted by careful planning from the beginning, and with its close relation with the King Mun's(文王) policy of civilian government(文治), it shows that the governing system of the state was completed during the reign of King Mun. Therefore, the construction of the capital and the principle of construction(造營原理) projected in it are based on the premise that the Chungwon culture(中原文化) was being understood to a considerable level, and this means that the view of the world(天下觀) that he wanted to implement expanded throughout the whole Balhae.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.383-383
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• 2012

최근 나노 소재의 활용 가능성이 확대되어감에 따라 다양한 소재의 나노구조체에 대한 연구가 진행되어 왔다. 그 중 은(Silver)은 열전도율과 전기전도율이 가장 우수한 금속으로 다양한 형태의 은 나노 입자를 형성할 수 있고. 이를 탄소, 비석, 고분자 등의 기판에 다양한 방법으로 성장시키는 연구가 진행되었다. 기판으로 사용되는 재료 중 탄소 복합소재는 내열성, 화학적 안정성, 열전도성, 저열팽창성에 따른 치수 안정성, 유연성 등의 우수한 특징을 지니고 있으며 최근까지 방열 소재로서 활용되고 있다. 본 연구에서는 탄소섬유의 표면에 다양한 결정 구조를 가지는 Ag seed 입자를 형성하고 폴리올 공정을 통하여 와이어 형태의 나노구조체를 성장시켜 그 형상제어 특성을 FE-SEM을 통하여 확인하였다.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.725-730
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• 2005

In the development of biomaterials as a substitute of hard tissues, the biocompatibility and osteoconductivity of the biomaterial are considered to be one of the most significant considerations. These biological properties of a material can be greatly improved by the modification of the surface properties by the depositing calcium phosphate thin films on the material since calcium phosphate films possess similar chemical compositions to hard tissues. The success of a material as a biomaterial will be determined by the interaction of the surface of the material with the adhesion molecules which induce cellular adhesion and biological responses of the adherent cells. Depending on the adsorption mechanisms and adsorbed conformation of the adhesion molecules on the surface of the biomaterial, cellular responses, such as adhesion, proliferation and differentiation of osteoblast cells, can be promoted or restricted. It has been reported that materials of which surfaces were modified with thin films of calcium phosphate appeared to be more osteoconductive. Rapid formations of bone nodule in addition to higher differentiations of osteoblast have been observed on the calcium phosphate thin films.

• Journal of Digital Convergence
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• v.17 no.11
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• pp.213-223
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• 2019

This study aims to prove the relationship between a TPB(theory of planned behavior) variables (subjective norms, attitudes, and self-efficacy), need to belong and personal growth initiatives to explain the reasons for users' shared behavior. 959 participants who had shared online video were collected as a sample through an online survey and the collected data were analyzed through structural equation modeling. The study found that need to belong affected attitudes to online video sharing and subjective norms, and that personal growth initiative also affected attitudes to online video sharing and self-efficacy. In addition, all three variables of TPB were affect the intend of online video sharing, and attitudes to online video sharing were affecting subjective norms and self-efficacy. This study is meaningful in that it demonstrated the user's intention to share online video through variables of TPB along with their need to belong and personal growth initiatives.