• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2200-2202
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• 2007

The local field distribution around gold nanosphere-gold plane junction has been studied using the finitedifference time-domain (FDTD) electrodynamics calculation procedure. We find that both the in-plane and out-of-plane polarized excitation produce enhanced field strong enough to explain the observed SERS activities of the junctions. Comparison with a simple dipole-image dipole model shows that the enhanced field primarily originates from the multipole-image multipole interaction, which indicates that the detailed fine-structures of the nanoparticles also play a significant role in the SERS activities as well.

• 한국전기전자재료학회논문지
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• 제26권3호
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• pp.227-231
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• 2013

Electrodeionization is a hybrid separation process of electrodialysis and ion exchange to produce high purity water under electric field. This article provides a fabrication result of hole patterned metal electrode for elecrodeionization system. The hole patterns have been fabricated by nanosphere lithography (NSL). The technique utilizes the self-assembled nanospheres as lens-mask patterns and collimated laser beam source. The hole patterns have a periodic array structure. The images of hole pattern on metal electrode prepared were observed by SEM. We believe that the periodic hole patterned metal electrode structure is a useful device applicable for metal mat electrode in electrodeionization system.

• Bulletin of the Korean Chemical Society
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• 제29권1호
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• pp.29-30
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• 2008

• 한국재료학회:학술대회논문집
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• 한국재료학회 2005년도 춘계학술발표대회 및 제8회 신소재 심포지엄 논문개요집
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• pp.194-194
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• 2005

• 한국진공학회:학술대회논문집
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• 한국진공학회 2008년도 제34회 동계학술대회 초록집
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• pp.148-148
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• 2008

• Journal of Pharmaceutical Investigation
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• 제36권6호
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• pp.355-361
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• 2006

Intraarticular corticosteroid injections for therapy of rheumatic arthritis are administered with the aim of optimal local anti-inflammatory effect at the injection site. Since the side effects of corticosteroidal drug, dexamethasone(DEX), administered at hish dose limited the therapeutic efficacy, there was a need to design a new drug delivery system for controlled release of dexamethasone. As a prodrug for continuous therapeutic efficacy, dexamethasone-21-palmitate(DEX-PAL) was prepared via esterification of palmitoyl chloride and dexamethasone. DEX-PAL was identified by NMR and MASS analysis. DEX-PAL or DEX was entrapped in lipid nanosphere which could be prepared by using a self emulsification-solvent evaporation method. Physicochemical characteristics such as mean particle diameter, zeta potential and drug loading efficiency of the lipid nanospheres were investigated with variation of either the kind of lipid or the lipid composition. The lipid nanospheres had a mean diameter $83{\sim}95$ nm and DEX-PAL loading efficiency of up to 95%. The drug loading efficiency increased with the increase of aliphatic chain length attached to the phospholipid. The incorporation of cationic lipid was very efficient for both reducing particle size of lipid nanospheres and enhancing drug loading efficiency. The lipid nanospheres containing DEX-PAL may be a promising novel drug carrier for the controlled release of the poorly water-soluble drugs.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.88.1-88.1
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• 2012

Silicon nanowires (SiNWs), due to their unusual quantum-confinement effects that lead to superior electrical and optical properties compared to those of the bulk silicon, have been widely researched as a potential building block in a variety of novel electronic devices. The conventional means for the synthesis of SiNWs has been the vapor-liquid-solid method using chemical vapor deposition; however, this method is time consuming, environmentally unfriendly, and do not support vertical growth. As an alternate, the electroless etching method has been proposed, which uses metal catalysts contained in aqueous hydrofluoric acids (HF) for vertically etching the bulk silicon substrate. This new method can support large-area growth in a short time, and vertically aligned SiNWs with high aspect ratio can be readily synthesized with excellent reproducibility. Nonetheless, there still are rooms for improvement such as the poor surface characteristics that lead to degradation in electrical performance, and non-uniformity of the diameter and shapes of the synthesized SiNWs. Here, we report a facile method of SiNWs synthesis having uniform sizes, diameters, and shapes, which may be other than just cylindrical shapes using a modified nanosphere lithography technique. The diameters of the polystyrene nanospheres can be adjustable through varying the time of O2 plasma treatment, which serve as a mask template for metal deposition on a silicon substrate. After the removal of the nanospheres, SiNWs having the exact same shape as the mask are synthesized using wet etching technique in a solution of HF, hydrogen peroxide, and deionized water. Different electrical and optical characteristics were obtained according to the shapes and sizes of the SiNWs, which implies that they can serve specific purposes according to their types.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.252.2-252.2
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• 2013

ZnO nanostructures have a lot of interest for decades due to its varied applications such as light-emitting devices, power generators, solar cells, and sensing devices etc. To get the high performance of these devices, the factors of nanostructure geometry, spacing, and alignment are important. So, Patterning of vertically- aligned ZnO nanowires are currently attractive. However, many of ZnO nanowire or nanorod fabrication methods are needs high temperature, such vapor phase transport process, metal-organic chemical vapor deposition (MOCVD), metal-organic vapor phase epitaxy, thermal evaporation, pulse laser deposition and thermal chemical vapor deposition. While hydrothermal process has great advantages-low temperature (less than $100^{\circ}C$), simple steps, short time consuming, without catalyst, and relatively ease to control than as mentioned various methods. In this work, we investigate the dependence of ZnO nanowire alignment and morphology on si substrate using of nanosphere template with various precursor concentration and components via hydrothermal process. The brief experimental scheme is as follow. First synthesized ZnO seed solution was spun coated on to cleaned Si substrate, and then annealed $350^{\circ}C$ for 1h in the furnace. Second, 200nm sized close-packed nanospheres were formed on the seed layer-coated substrate by using of gas-liquid-solid interfacial self-assembly method and drying in vaccum desicator for about a day to enhance the adhesion between seed layer and nanospheres. After that, zinc oxide nanowires were synthesized using a low temperature hydrothermal method based on alkali solution. The specimens were immersed upside down in the autoclave bath to prevent some precipitates which formed and covered on the surface. The hydrothermal conditions such as growth temperature, growth time, solution concentration, and additives are variously performed to optimize the morphologies of nanowire. To characterize the crystal structure of seed layer and nanowires, morphology, and optical properties, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and photoluminescence (PL) studies were investigated.

• 접착 및 계면
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• 제3권2호
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• pp.9-16
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• 2002

자가유화방식의 수분산 폴리우레탄의 경우, 이온성 그룹이 포함된 프리폴리머를 중화시켜 수분산시킨 후 분자량을 증가시키기 위해 사슬연장을 하게 된다. 본 연구에서는 아민계 사슬연장제를 사용하여 사슬연장 시 연속상의 pH의 변화를 관찰하였으며, 이온성 그룹의 함량, 사슬연장제의 사슬 길이와 투입 속도 등과 같은 공정 변수에 따른 최적의 사슬연장 정도와 사슬연장 시 평균 입도 변화를 분석하였다. 투입되는 사슬연장제의 농도가 증가함에 따라서 연속상의 pH가 증가하게 되고, 사슬연장 정도에 따른 pH 변화곡선의 변곡점으로부터 최적의 사슬연장제 함량을 결정하였다. 사슬연장제 투입 속도에 따른 평균 입도 크기 변화의 경우, 초기 사슬연장전의 평균 입자 크기는 거의 비슷하다가 최종 사슬연장이 끝난 후에 사슬연장제 투입 속도가 빠른 쪽의 평균 입도 크기가 증가한다는 사실이 관찰되었다. 이온성 그룹의 함량이 증가할수록 친수성기의 농도가 증가하므로 평균 입도 크기는 감소한다. 사슬연장제의 사슬 길이의 영향이 최적의 사슬연장 정도를 결정하는데 큰 영향은 미치지 않고, 사슬의 길이가 긴 아민류를 사용하였을 시 입자와 입자 사이에서 사슬연장 반응을 통해 입자의 크기가 크게 증가하는 경향이 관찰되었다.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.945-948
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• 2014