• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.191.1-191.1
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• 2014

Crystallization has become the most popular technique for the separation of enantiomers since the Pasteur's discovery. To investigate mechanism of crystallization of chiral molecules, it is necessary to study self-assembled structures on two-dimensional surface. Here, we have studied two-dimensional self-assembled structures of an unnatural amino acid, (S)-${\beta}$-methyl naphthalen-1-${\gamma}$-aminobutyric acid (${\gamma}^2$-1-naphthylalanine) on Au(111) surface at 150 K using scanning tunneling microscopy (STM). At initial stage, we found two chiral honeycomb structures which are counter-clockwise and clockwise configurations in one domain. The molecules are arranged around molecular vacancies, dark hole. By further increasing the amounts of adsorbed ${\gamma}^2$-1-naphthylalanine, a well-ordered square packed structure was observed. In addition, we found the other structure that molecules were trapped in the pore of the hexagonal molecular assembly.

• Bulletin of the Korean Chemical Society
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• 제26권1호
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• pp.127-130
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• 2005

The early stage of the self assembly for octadecyltrichlorosilane (OTS)-based monolayers is investigated using atomic force microscopy (AFM). Height measurements using AFM prove that the island height of the monolayers gradually increases with increasing the island size, and is close to the limiting value (h = $\sim$25 $\AA$) after d = $\sim$600 nm in size. Since the theoretical length of a covalently bound OTS molecule is 26.2 Å, the limiting value of the island height means that the islands with d ${\geq}$ 600 nm consist of close-packed, fully extended chains. The heights for the islands with d < 600 nm are lower than the limiting value and decrease with decreasing the island sizes. This observation indicates that the OTS molecules in the small islands are less densely packed, and that the packing densities of the islands increase as the islands grow in size.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권3호
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• pp.133-139
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• 2007

Future MEMS systems will be composed of larger varieties of devices with very different functionality such as electronics, mechanics, optics and bio-chemistry. Integration technology of heterogeneous devices must be developed. This article first deals with the current development trend of new fabrication technologies; those include self-assembling of parts over a large area, wafer-scale encapsulation by wafer-bonding, nano imprinting, and roll-to-roll printing. In the latter half of the article, the concept towards the heterogeneous integration of devices and functionality into micro/nano systems is described. The key idea is to combine the conventional top-down technologies and the novel bottom-up technologies for building nano systems. A simple example is the carbon nano tube interconnection that is grown in the via-hole of a VLSI chip. In the laboratory level, the position-specific self-assembly of nano parts on a DNA template was demonstrated through hybridization of probe DNA segments attached to the parts. Also, bio molecular motors were incorporated in a micro fluidic system and utilized as a nano actuator for transporting objects in the channel.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.280-280
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• 2013

In green plants, energy generation is accomplished through light-harvesting photosystem, which utilize abundant visible light and multi-stepwise redox reaction to oxidize water and reduce NADP+, transferring electrons efficiently with active cofactors1. Inspired by natural photosynthesis, artificial solar water-splitting devices are being designed variously. However, the several approaches involving immobilization2, conjugation3, and surface modification4 still have limitations. We have made artificial photosynthesis templates by self-assembling tyrosine-based peptide to mimick photosystem II. Porphyrin sensitizer absorbing blue light strongly was conjugated with the templates and they were hybridized with cobalt oxide through the reduction of cobalt ions in an aqueous solution. The formation of hybrid templates was characterized using TEM, and their water oxidation performance was measured by fluorescence oxygen probe. Our results suggest that the bio-templated assembly of functional compounds has a great potential for artificial photosynthesis.

• Korean Chemical Engineering Research
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• 제46권1호
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• pp.1-6
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• 2008

블록공중합체(block copolymer)는 각 고분자 블록의 상대적인 조성비와 분자량에 따라 구, 실린더, 라멜라 등의 다양한 자기조립 나노구조를 형성하는 것으로 알려져 있다. 최근에는 블록공중합체의 자기조립 나노구조를 이용하여 나노복합재료, 포토닉 크리스탈, 나노선, 자기저장매체, 플래시 메모리 소자 등에 적용하려는 연구들이 활발히 진행되고 있다. 그러나 자연적으로 형성되는 블록공중합체 나노구조는 수많은 결함구조들을 포함하고 있어 실제 소자 적용에 큰 걸림돌이 되고 있다. 블록공중합체 나노구조의 실제적인 응용을 위해서는 박막상태의 시료 내에서 나노구조의 배향과 배열을 원하는 형태로 조절할 수 있는 공정의 확립이 선행되어야 한다. 즉, 블록공중합체의 자기조립을 나노기술분야에 적용하기 위해서는 대면적으로 완벽히 제어된 블록공중합체 나노구조를 구현하는 것이 필요하다.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권3호
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• pp.115-118
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• 2005

Currently, molecular devices are reported utilizing active self-assembled monolayers (SAMs) containing the nitro group as the active component, which has active redox centers [1]. SAMs are ordered molecular structures formed by the adsorption of an active surfactant on a solid surface. The molecules will be spontaneously oriented toward the substrate surface and form an energetically favorable ordered layer. During this process, the surface-active head group of the molecule chemically reacts with and chemisorbs onto the substrate In this paper, the electrical properties of the 4'4- di(ethynylphenyl)-2'-nitro-1-benzenethiolate was confirmed. This material is well known as a conducting molecule having possible application to molecular level negative differential resistance (NDR) device. To deposit the self-assembly monolayers onto the gold electrode, the prefabricated Au(1 l l) substrates were immersed into 0.5[mM/l] self-assembly molecule in THF solution. Then, the electrical properties and surface morphologies of 4' 4-di(ethynylphenyl)-2' -nitro-1-benzenethiolate were measured by using the ultra-high vacuum scanning tunneling microscopy (UHV-STM).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1520-1522
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• 2003

Molecular self-assembled of surfactant viologen are of recent interest because they can from functional electrodes as well as micellar assemblies, which can be Profitably utilized for display devices, photoelectrochemical studies and electrocatalysis as electron acceptor or electron mediator. Fromherz et al studied the self-assembly of thiol and disulfide derivatives of viologens bearing long n-alkyl chains on Au electrode surface. The electrochemical behavior of self-assembled viologen monolayer has been investigated with QCM, which has been known as nano-gram order mass detector. The self-assembly process of viologen was monitored using resonant frequency (${\Delta}$F) and resonant resistance (R). The redox process of viologen was observed with resonant frequency (${\Delta}$F).

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.58-58
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• 2003

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 춘계학술발표대회 및 제12회 신소재 심포지엄
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• pp.5.1-5.1
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• 2007

• 한국고분자학회지:고분자과학과기술
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• 제21권3호
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• pp.228-235
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• 2010