• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.21-21
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• 2006

21세기 정보통신 및 관련 소재의 연구방향은 새로운 기능성 확보, 극한적 제어성, 복합 및 융합이라는 경향으로 발전해 가고 있다. 반도체 기술 분야에서 현재의 공정적 한계를 극복하고 새로운 기능성을 부여하기 위해 나노 합성과 배열을 기본으로 하여 bottom-up 방식의 나노소자 구현이 큰 주목을 받고 있다. 나노선의 경우 나노 스케일의 dimension, 양자 제한 효과, 우수한 결정성, self-assembly, internal stress 등 기존 벌크형 소재에서 발견할 수 없는 새로운 기능성이 나타나고 있어 바이오, 에너지, 구조, 전자, 센서 등의 분야에서의 활용이 가능하다. 현재 국내외적으로 반도체 나노선으로 널리 연구되고 있는 재료는 ZnO, $SnO_2$, SiC 등이 중심이 되고 있다. 이중 ZnO 나 노선의 합성을 위해서는 thermal CVD, MOCVD, PLD, wet-chemical 등 다양한 방법이 사용되고 있다. 특히 MOCVD 방법에 의해 수직 정렬된 ZnO 나노막대를 성장할 수 있다. 이러한 나노막대는 MO 원료 및 산소 공급량을 적절히 제어함으로서 수직 배향 및 나노선의 구경 제어가 가능하며, 나노 막대의 크기 제어와 관련해서는 반응 관내의 DEZn 와 $O_2$의 양을 변화시켜 구조체의 크기를 수 십 ~ 수 백 나노미터의 크기로 제어할 수 있다. 본 연구는 이러한 ZnO 나노선의 성장과정에서 $210^{\circ}C$ 이하의 저온에서 성장한 ZnO 버퍼층을 이용해 나노구조의 형상을 제어하고자 하였다. 특히 ZnO 저온 버퍼층의 두께에 따라 나노막대의 직경변화, 수직배향성, 형상변화의 제어가 가능하였다. 나노막대의 특성 평가는 TEM, SEM, PL, XRD 등을 이용하여 구조적, 결정학적, 광학적 특성을 분석하였다.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.583-590
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• 2016

This study aims to suggest a desirable dietary methods based on the oriental medicated dietary effects based on the schema of four qi and five flavors of foods originated from the yin-yang and five phase theory through clear understanding of the theory of oriental medicated dietary in a modern point of view, and through experimental analysis on the nutrient and dietary effect of 4 medicinal plants. We expect it can show us the way for promoting more healthy life styles and for preventing adult diseases by following our own medicated dietary theory. We should develop our own culinary and dietary culture which is suitable for our physical and genetic conditions for our healthy and happy lives. To successfully develop and introduce them, we should analyze their dietary effects scientifically based on both the theory of nutrialogy and the oriental medicated dietary in a modern point of view.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.59-59
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• 2007

최근 GaN계 LED를 대체할 만한 물질로 주목받고 있는 ZnO는 단결정 박막성장의 어려움, 동일접합 LED 소자구현을 위한 p-ZnO 성장의 어려움 3원계 합금제작의 어려움 등으로 소자제작에 있어 고전을 하고 있다. 특히 이러한 문제점을 극복하고자 하는 방안으로 양자 제한 효과, 탁월한 결정성, self-assembly, internal stress 등의 새로운 기능성을 지닌 ZnO 나노구조가 제시되었다. 하지만 나노구조를 이용한 다이오드 제작에서도 금속전극의 접합이라는 문제의 벽에 가로막혀 있다. 본 실험에서는 자체 개발된 MOCVD 장비를 이용한 일차원 ZnO 나노선을 성장한 이후 연속적으로 박막을 성장하여 금속전극의 접합을 시도하였다. 이종접합구조 뿐만 아니라 일차원 및 이차원 구조의 복합구조는 일반 다결정 박막보다 결정성에서 우수한 특성을 보였으며, 다이오드 제작시에 높은 효율을 보였다.

• Composites Research
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• v.32 no.3
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• pp.134-140
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• 2019

Graphene nanoplatelets (GNP), one of the graphene derivatives is famous as the most proper candidate for industrial applications. However, current performance of GNPs as reinforcing filler in composites is limited by their agglomeration and physicochemical heterogeneity. Herein, an approach to produce non-covalently functionalized GNPs (F-GNPs) is reported which possesses potential to be extended as the industrial level of mass production. The one-step functionalization process uses melamine, a low-cost chemical, to prevent agglomeration and dispersion in polar solvents. Furthermore, a purification strategy called salting-out process based on differences in the dispersibility of the individual F-GNP flakes is reported to separate F-GNPs. The functionalization and separation process developed in this paper provides a strategy to use GNPs at the industrial level in composite applications.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1534-1540
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• 2004

This study aims to obtain fundamental understandings involving the manufacturing processes of nano-composites with chemically surface-modified multi-walled carbon nanotubes(MWCNTs), and explore the role of functionalized MWCNTs in the epoxy/MWCNT composites. For this purpose, MWCNTs were purified by the thermo-chemical oxidation process, and incorporated into an epoxy matrix by in situ polymerization process, the surface of MWCNTs were functionalized with carboxyl functions which were demonstrated by an infrared spectroscopy. The mechanical properties of epoxy/MWCNT nano-composites were measured to investigate the role of a chemically functionalized carbon nanotubes. To improve the dispersion quality of MWCNTs in the epoxy matrix, methanol and acetone were exploited as dispersion media with sonification. The epoxy/MWCNT nano-composites with 1 or 2 wt.％ addition of functionalized carbon nanotubes show an improved tensile strength and wear resistance in comparison with pure epoxy, which shows the mechanical load transfer improves through chemical bonds between epoxy and functionalized MWCNTs. The tensile strength with 7 wt.％ functionalized MWCNTs increases by 28％ and the wear resistance is dramatically improved by 100 times.

• Composites Research
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• v.37 no.1
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• pp.53-57
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• 2024

Numerous studies have explored structural antennas for integrating advanced wireless systems into aircraft without altering their external form. However, much of the research on structural antennas has focused on patch antennas, which are characterized by limitations such as narrow frequency bands and low directivity. In contrast, the Vivaldi antenna, widely utilized in wireless applications, offers the advantages of a wide frequency band and high directivity. Nevertheless, its application to aircraft has been challenging due to radiation direction constraints. In this study, we endeavor to address this issue by proposing the application of the antenna patch onto the honeycomb wall, thus enabling the use of the Vivaldi antenna on aircraft. The impact of the honeycomb structure on antenna radiation performance was analyzed, and the potential of the honeycomb Vivaldi antenna was validated through simulation.

• Composites Research
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• v.25 no.6
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• pp.178-185
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• 2012

One of a unique technique in manipulating a multifunctional composite is demonstrated in this study. An electric field is applied to a liquid suspension in order to align the inclusions along with the direction electric field. This is called FAiMTa(Field Aided Micro Tailoring). It makes orthotropic polymer composites by arranging the micro and/or nano size particle inclusions in chain-line formation. Several kinds of particles such as $Al_2O_3$, graphite, CNT(Carbon Nano Tube), W(Tungsten) are tested to verify the effectiveness of the FAiMTa. The particles redistributed in an epoxy suspension and their coupons show that mechanical and thermal properties of orthotropic and random composites containing those particles depend on the trend of particles' alignment. The micro-images of the functional composite from FAiMTa have been captures and their physical properties demonstrate their wide-range and state-of-the-art application for advanced multifunctional composites.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.214-214
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• 2003

제지산업에 경쟁력을 부여할 수 있는 방법의 일환으로 제지용 도공안료의 표면개질을 시도하였다 은(Ag)이 항균력이 있다는 것이 여러 사람에 의해 증명된바 있으므로 이 은의 항균력을 제지용 무기안료에 이산화티탄과 함께 표면개질하고 다기능성 복합 항균분체를 설계하였다. 표면개질장치에 설치한 기상분사장치를 통해 은 용액을 고압기상분사로 TiO$_2$입자 표면에 Coating 하였다 이때의 분무각도는 60$^{\circ}$이고 오리피스 직경은 0.6mm, 분사 압력은 14kgf/$\textrm{cm}^2$ 이다. TiO$_2$에 은 용액을 기상분사하여 코팅시킨 후 표면개질 계산식에 의한 배합비로 모입자(clay, CaCO$_3$, PE)와 자입자(TiO$_2$)를 혼합하였고, 분체의 대전현상을 이용하여 모입자 주위에 자입자를 부착시킨 후, 고속기류중 충격력으로 표면개질처리를 하였다 표면개질 장치를 사용하여 제지용 무기안료 표면에 은용액이 코팅된 TiO$_2$를 개질 시켰다. 각종 물성(항균성, 백색도, 산란도)과 XRD, SEM 측정을 통해 기능성 항균분체의 실용방안 가능성에 대하여 조사하였다.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.272-283
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• 2021

The purpose of research is to suggest the direction of rural tourism and food products by looking at the relevance of the intrinsic motivation and food preference. Through the analysis, factors of 'leisure oriented', 'family oriented', 'relationship oriented', 'health oriented', and food preference 'cooking health', 'material function', 'local resource' and 'consume experience' were extracted. Through the correlation analysis, 'leisure and health oriented' was found to be significant with cooking health, 'relationship and health oriented' was significant with material function, 'leisure, family and relationship oriented' was significant with local resource and 'relationship oriented' was significant with consume experience. Therefore, tourists who want rest, healing and health need to provide healthy dishes, tourists who want family and leisure provide local or special dishes, and tourists who want to have a relationship with people need to provide functional foods or herbal medicine dishes. Food products that meet the needs of tourists will induce revisit by increasing tourist satisfaction and bring economic revitalization of the region through the expansion of rural tourism.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.2
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• pp.139-145
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• 1998

Filament winding method is widely used for composite fabrications using low viscosity liquid for-mation and processing asymmetrical structures of pressure vessel pipe rocket motor case etc. The filament winding method is affected by several parameters such as pot life of process time viscosi-ty of resin filament winding temperature and schedules curing condition and post curing condi-tion of resin. To develope high functional composite materials the rotation(5, 15, 20, 30rpm) of the winding machine was controlled by D.C motor. And the wiper to give proper tension was equipped between strand and resin bath. The resin is hooked by the design wiper. The adequate cure schedule was found by DSC. NOL ring test is carried out to investigate the basic physical properties such as design technology. The void contents in filament winding is generally higher than that of the prepreg laminated plate. These high contents of void can make a crack in resin in spite of low deformation. These problem was solved by giving tension in processing. To improve the characteristics of fiber volume fraction void contents resin/fiber bonding the winding speedc is changed under constant tension. It was found that resin impregnation was not different from in fiber contents void contents at the range of 0.5~1kg tension but it was found that resin was not impregnated at the above of 1.5kg tension. In burst test a pure PE liner was failed at a nozzle part under the $14kg/\textrm{cm}^2$ pressure but a pressure vessel of CNG was failed at a cylinder part under the $200kg/\textrm{cm}^2$ pressure.