• 미생물학회지
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• 제52권2호
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• pp.212-219
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• 2016

식물 근권 토양으로부터 색소생성 균주 106균주를 수집하여 색소 생성능이 우수한 균주로부터 노란색(33개), 주황색(12개), 분홍색, 빨간색, 갈색 그리고 보라색 총 49개의 세균색소를 추출하였다. 식물병원균에 대한 항균활성능이 우수한 색소를 선발하기 위하여 고추점무늬병원균(Xanthomonas axonopodis), 흑마병원균(Xanthomonas campestris)과 딸기잿빛곰팡이병원균(Botrytis cinerea), 고추탄저병원균(Colletotrichum acutatum), 그리고 시들음병원균(Fusarium oxysporum)을 대상으로 항균활성 검정을 수행하였다. 색소생성 Chryseobacterium sp. RBR9 균주가 생산하는 노란색 색소와 Methylobacterium sp. RI13 균주가 생산하는 빨간색 색소는 X. axonopodis와 X. campestris에 항세균 활성을 나타내었다. 차나무 토양으로부터 분리된 Collimonas sp. DEC-B5가 생산하는 보라색 색소는 항세균 활성과 더불어 B. cinerea와 Colletotrichum acutatum에 항진균활성을 나타내었다. 특히, 보라색 색소는 최소저해 농도 $20{\mu}M$에서 B. cinerea를 65% 이상 생육 저해하였다. 항진균활성 보라색 색소를 HPLC 분석한 결과, violacein (91.6%)와 deoxyviolacein(8.4%)으로 동정되었다. 보라색 색소 violacein의 생산량은 SCB 배지에서 $43.2{\mu}M$이었고 D-mannitol 1.5%, yeast extract 0.2%를 첨가한 경우 $431.6{\mu}M$로 약 10배 높은 색소 생성량을 나타내었다. 본 연구에서 분리된 Collimonas sp. DEC-B5가 생산하는 violacein 색소는 딸기잿빛곰팡이병원균 방제제로 활용 가능성이 확인되었다.

• 대한기계학회논문집A
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• 제29권2호
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• pp.228-231
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• 2005

In this paper, we present reusable quartz master fabricated by electron-beam lithography and dry etching process of quartz, and results of injection molding based on the reusable quartz master for the manufacturing of nano-scale information media. Since patterned structures of photoresist can be easily damaged by separation (demolding) process of nickel stamper and master, a master with photoresist cannot be reused in stamper fabrication process. In this work, we have made it possible of the repeated use of master by directly patterning on quart in nickel stamper fabrication process. We have designed and fabricated four different specimens including 100nm, 140nm 200nm and 400nm pit patterns. In addition, both intaglio and embossed carving patterns are fabricated for each specimen. In the preliminary test of injection molding, we have fabricated polycarbonate patterns with varying mold temperature. We have experimentally verified the fabrication process of the reusable quart master and possibility of quartz master as direct stamper.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1532-1536
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• 2007

A plastic substrate with tiny rectangular pillars less than 100nm is injection molded to study pattern replication in injection molding. The size of the substrate is 50mm ${\times}$ 50mm and 1mm thick. The substrate has 9 patterned areas of which size is 2mm ${\times}$ 2mm respectively. The lengths of the pillars are 50nm, 100nm, 150nm and 200nm and the width and height are 50nm and about 100nm respectively. A pattern master is fabricated by e-beam writing using positive PR(photo resist) and then a nickel stamper replicated from the PR master by nickel electro-plating. Cr is deposited on the PR pattern master before nickel electro-plating as a conducting layer. Using this nickel stamper, several injection molding experiments are done to investigate effects of the injection molding parameters such as mold temperature, injection rate, packing pressure or pattern location on the replication of the patterns under 100nm.

• 소성∙가공
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• 제13권4호
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• pp.326-333
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• 2004

The nanoprobe based on lithography, mainly represented by SPM based technologies, has been recognized as a potential application to fabricate the surface nanosctructures because of its operational versatility and simplicity. However, nanoprobe based on lithography itself is not suitable for mass production because it is time a consuming method and not economical for commercial applications. One solution is to fabricate a mold that will be used for mass production processes such as nanoimprint, PDMS casting, and others. The objective of this study is to fabricate the silicon stamper for PDMS casting process by a mastless fabrication technique using the combination of nano/micro machining by Nanoindenter XP and KOH wet etching. Effect of the Berkovich tip alignment on the deformation was investigated. Grooves were machined on a silicon surface, which has native oxide on it, by constant load scratch (CLS), and they were etched in KOH solutions to investigate chemical characteristics of the machined silicon surface. After the etching process, the convex structures was made because of the etch mask effect of the mechanically affected layer generated by nanoscratch. On the basis of this fact, some line patterns with convex structures were fabricated. Achieved groove and convex structures were used as a stamper for PDMS casting process.

• 소성∙가공
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• 제12권7호
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• pp.640-646
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• 2003

The nanoprobe based on lithography, mainly represented by SPM based technologies, has been recognized as potential application to fabricate the surface nanostructures because of its operational versatility and simplicity. The objective of the work is to suggest new mastless pattern fabrication technique using the combination of machining by nanoindenter and KOH wet etching. The scratch option of the nanoindenter is a very promising method for obtaining nanometer scale features on a large size specimen because it has a very wide working area and load range. Sample line patterns were machined on a silicon surface, which has a native oxide on it, by constant load scratch (CLS) of the Nanoindenter with a Berkovich diamond tip, and they were etched in KOH solutions to investigate chemical characteristics of the machined silicon surface. After the etching process, the convex structure was made because of masking effect of the affected layer generated by nano-scratch. On the basis of this fact, some line patterns with convex structures were fabricated. Achieved patterns can be used as a mold that will be used for mass production processes such as nanoimprint or PDMS molding process. All morphological data of scratch traces were scanned using atomic force microscope (AFM).

• 대한금속재료학회지
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• 제49권1호
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• pp.32-39
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• 2011

The present investigation was performed on the die compaction and sintering behavior of Fe micro-nano mixed powder with a mixed binder for powder injection molding. Warm die compaction of the feedstock for simulation of the static injection molding process was conducted using a cylindrical mold of 10 mm diameter at $100^{\circ}C$ under 4MPa. The die compaction of the micro-nanopowder feedstock underwent a uniform molding behavior showing a homogeneous distribution of nanopowders among the micropowders without porosity and distortion. After debinding, the powder compact maintained a uniform structure without crack and distortion, leading to a high green density of 64.2% corresponding to the initial powder loading of 65%. The sintering experiment showed that the micro-nanopowder compact underwent a near full and isotropic densification process during sintering. It was observed that the nanopowders effectively suppressed the growth of micropowder grains during densification process. Conclusively, the use of nanopowder for PIM feedstock might provide a new concept for processing a full density PIM parts with fine microstructure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1206-1209
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• 2005

In recent, injection molding process for features in sub-micron scale is under active development as patterning nano-scale features, which can provide the master or stamp for molding, and becomes available around the world. Injection molding has been one of the most efficient processes for mass production of the plastic product, and this process is already applied to nano-technology products successfully such as optical storage media like DVD or BD which is a large area plastic thin substrate with nano-scale features on its surface. Bio chip for like DNA sequencing may be another application of this plastic substrate. The DNA can be sequenced using order of 100 nm pore structure when making the DNA flow through the pore structure. Agarose gel and silicon based chip have been used to sequence the DNA, but injection molded plastic chip may have benefit in terms of cost. This plastic DNA sequencing chip has plenty of pillars in order of 100 nm in diameter on the substrate. When the usual features in case of DVD or BD have very low aspect ratio, even less than 0.5, but the DNA chip will have relatively high aspect ratio of about 2. It is not easy to injection mold the large area thin substrate with sub-micron features on its surface due to the characteristics of the molding process and it becomes much more difficult when the aspect ratio of the features becomes high. We investigated the effect of the molding parameters for injection molding with high aspect ratio nano-scale features and injection molded some plastic DNA sequencing chips. We also fabricated PR masters and Ni stamps of the DNA chip to be used for molding

• 식물병연구
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• 제21권1호
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• pp.12-19
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• 2015

나노 화합물을 이용하여 식물병원성 미생물의 항균활성을 검정하기 위하여 실험을 수행하였다. 12가지 나노 화합물을 이용하였으며, 곰팡이 3종과 수박과실썩음병(BFB: Acidovorax citrulli) 16계통을 이용하여 실험한 결과, 곰팡이 병원균에 대하여 C. destructans의 경우 항균효과가 없는 것으로 확인되었으며, P. ultimum의 경우 Brass/Glucose 1,000 ppm에서 94%의 균사 생장 억제 효과를 확인하였으며, R. solani는 Ag/Glucose 3,000 ppm에서 약간의 효과는 있었으나 매우 경미한 것을 확인하였으며, 나머지 나노 화합물에서는 항균 효과가 없는 것으로 확인 되었다. A. citrulli의 경우 석회에서 가장 높은 항균 활성을 확인하였으며, Cu/Salt 1,000 ppm는 7종에 대하여 최소 97% 의 항균 활성을 보였으며, 5종에 대하여 99%의 높은 항균활성을 확인하였다. Ag/Glucose 1,000 ppm은 7종의 수박과실썩음병(BFB) 병원균 A. citrulli에 대하여 63%의 항균활성을 보여주었다. $Brass/CaCO_3$ 3,000 ppm은 석회 보다는 조금 낮은 92%의 항균 활성을 보여 주었으며, 나머지 나노 화합물은 24-70%의 항균활성을 확인하였다.

• 한국전기전자재료학회논문지
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• 제30권12호
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• pp.751-756
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• 2017

A molding-type power inductor is an inductor that uses a hybrid material that is prepared by mixing a ferrite metal powder coated with an insulating layer and an epoxy resin, which is injected into a coil-embedded mold and heated and cured. The fabrication of molding-type inductors requires various techniques such as for coil formation and insertion, improving the magnetic properties of soft magnetic metal powder, coating an insulating film on the magnetic powder surface, and increasing the packing density by well dispersing the powder in the epoxy resin. Among these aspects, researches on additives that can disperse the metal soft magnetic powder having the greatest performance in the epoxy resin with high charge have not been reported yet. In this study, we investigated the effect of silanes, KBM-303 and KBM-403, and a commercial dispersant on the dispersion of metal soft magnetic powders in epoxy resin. The sedimentation height and viscosity were measured, and it was confirmed that the silane KBM-303 was suitable for dispersion. For this silane, the packing density was as high as about 72.49%. Moreover, when 1.2 wt% of dispersant BYK-103 was added, the packing density was about 80.5%.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.159-160
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• 2006

A novel approach to the manufacture of biocompatible ceramic scaffold for tissue engineering using micro-stereolithography system is introduced. Micro-stereolithography is a newly proposed technology that enables to make a 3D micro structure. The 3D micro structures made by this technology can have accurate and complex shape within a few micron error. Therefore, the application based on this technology can vary greatly in nano-bio fields. Recently, tissue-engineering techniques have been regarded as alternative candidate to treat patients with serious bone defects. So many techniques to design and fabricate 3D scaffolds have been developed. But the imperfection of scaffold such as random pore size and porosity causes a limitation in developing optimum scaffold. So scaffold development with controllable pore size and fully interconnected shape have been needed for a more progress in tissue engineering. In this paper, bone scaffold was developed by applying the micro-stereolithography to the mold technology. The scaffold material used was HA(Hydroxyapatite) nano powder. HA is a type of calcium phosphate ceramic with similar characteristic to human inorganic bone component. The bone scaffold made by HA is expected, in the near future, to be an efficient therapy for bone defect.