• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1900-1902
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• 2005

본 연구에서는 scanning probe microscopy(SPM)을 이용하여 국소영역에서 silicon nanocrystal(Si NC)의 전기적 특성을 분석하였다. Si NCs은 압축된 silicon powder를 laser로 분해하는 laser ablation 방식으로 제조되었고, sharpening oxidation 과정을 통하여 Si NC 주변에 oxide shell을 형성시켰다. 이 과정에서 Si NCs은 $10{\sim}50 nm$의 크기와 약 $10^{11}/cm^2$의 밀도로 $SiO_2$층에 증착되었다. SPM의 conducting tip을 통하여 전하는 각각의 Si NC로 주입되게 되고, 이로 인하여 발생하는 SCM image와 dC/dV curve의 변화를 통하여 Si NC에서 전하 거동을 모니터 하였다. 또한 국소영역에서 Si NC의 전기적 특성을 MOS capacitor 구조에서의 C-V 특성과 비교 분석하였다.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.1-6
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• 2008

Block copolymers spontaneously assemble into various nanoscale structures such as spheres, cylinders, and lamellar structures according to the relative volumn ratio of each macromolecular block and their overall molecular weights. The self-assembled structures of block copolymer have been extensively investigated for the applications such as nanocomposites, photonic crystals, nanowires, magnetic-storage media, flash memory devices. However, the naturally formed nanostructures of block copolymers contain a high density of defects such that the practical applications for nanoscale devices have been limited. For the practical application of block copolymer nanostructures, a robust process to direct the assembly of block copolymers in thin film geometry is required to be established. To exploit self-assembly of block copolymer for the nanotechnology, it is indispensible to fabricate defect-free self-assembled nanostructure over an arbitrarily large area.

• The Journal of the Convergence on Culture Technology
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• v.1 no.2
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• pp.65-69
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• 2015

Teeth and bones are very resistance to high temperatures and remain recognizable even after prolonged exposures to heat. The effects of heating and burning on teeth have been studied with the aim of discerning a characteristic signature withstanding high temperature, but there have been few studies about a human cremated ash, especially Korea. We are recognizable by elemental composition and can be detected in human cremated ash samples by Scanning electromicroscopy/Energy dispersive X-ray spectrometry analysis(SEM/EDS), cremated, at $800{\sim}900^{\circ}C$ for 1 hour. In this temperature range, different crystals morphologies(spherical, irregular and hexagonal) are observed in SEM. Calcium(Ca) and oxygen(O) increases steadily after cremation in EDS. We suggest that cremated bone have been provided with calcium oxide(CaO) formation at temperature above $900^{\circ}C$. This study offers basic data to assess the structure and elemental compositions of human ash and to determine if these remain identifiable after exposure to extreme temperatures.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.518-527
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• 2015

In this study, nanocomposite mats consisting of cellulose nanocrystals (CNCs) and poly(lactic acide) (PLA) were electrospun from a suspension mixture consisting of tetrahydrofuran at room temperature. Morphology study showed that fibers of electrospun composite mats were aligned in three dimensional surface along the fiber long-axis. Average diameter of the electrospun fibers decreased with an increase in the CNC loading level. Tensile strength of the electrospun fibers mat decreased with an increase in the CNC loading level because of bead formation in the formed fibers and low interfacial bond strength between PLA and CNC. Meanwhile, thermal stability of the electrospun nanocomposite mats was effectively improved as the amount of CNC increased.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.3
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• pp.306-312
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• 2016

Gargle solution has typically been used for the prevention of oral infectious disease such as dental caries and periodontitis. However, the use of most gargle solutions is controversial in application for children because some gargle solutions have harmful side effects. Electrolyzed water is generated by passed an electric current and has antimicrobial activity. The purpose of this study was to investigate and compare the efficacy of electrolyzed water in various conditions for eliminating cariogenic bacteria. Electrolyzed water was generated by a platinum electrode in the presence of sodium chloride at various concentrations. Streptococcus mutans and Streptococcus sobrinus were cultivated into a brain heart infusion broth. After harvesting planktonic bacteria, the pellets were treated with the electrolyzed water and commercial gargle solutions and plated on a mitis-salivarius agar plate. Also, the anti-biofilm activity of the electrolyzed water and commercial gargle solutions was investigated after biofilm formation of S. mutans and S. sobrinus. The bacteria in the biofilm were plated onto a mitis-salivarius agar plate. The plates were incubated, and the colony forming unit was measured. The electrolyzed water containing sodium chloride showed significant antibacterial activity against S. mutans and S. sobrinus as well as some gargle solutions. Furthermore, the electrolyzed water had more disruptive effect on the biofilm of S. mutans and S. sobrinus and killed more bacteria in the biofilm than commercial gargle solutions. The results demonstrate that electrolyzed water may be a useful gargle solution for prevention of dental caries.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.2
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• pp.99-103
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• 2010

Waxes, or long-chain hydrocarbons, may be obtained naturally from animals, vegetables, and mineral waxes, or may be synthesized. The oil-wax gels are widely applied to lots of cosmetics such as lipsticks. For example, the lipstick texture is strongly dependent on the glossiness of the oil-wax gels. Extensive research has been carried out to investigate the lattice structure of wax mixture in pure solvents (hydrocarbons) and defined mixtures. However, only a limited amount of work has been published on the lattice structure of wax matrixes in undefined mixtures. The objective of this study was to investigate the relationship between the lattice structure of ceresin wax and different wax mixtures and the glossiness of oil-wax gels. Recently visual factors such as the glossiness of skin are generally known as the words to express the beauty. The mechanism of glossiness has been suggested to understand the changes that occur in the lattice structure of the wax matrixes when they are forming gels and also the effects of the nature of solvent. The present work investigates the lattice structure of the wax matrixes and glossiness of oil-wax gels obtained from ceresin and microcrystalline wax as well as of the gels formed by different waxes in solvent.