• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.6
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• pp.440-443
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• 2010

We report a top-down approach based on atomic force microscopy (AFM) local anodic oxidation for the fabrication of the nano-pattern field effect transistors (FETs). AFM anodic oxidation is relatively a simple process in atmosphere at room temperature but it still can result in patterns with a high spatial resolution, and compatibility with conventional silicon CMOS process. In this work, we study nano-pattern FETs for various cross-bar distance value D, from ${\sim}0.5\;{\mu}m$ to $1\;{\mu}m$. We compare the optical characteristics of the patterned FETs and of the reference FETs based on both 2-dimensional simulation and experimental results for the wavelength from 100 nm to 900 nm. The simulated the drain current of the nano-patterned FETs shows significantly higher value incident the reference FETs from ${\sim}1.7\;{\times}\;10^{-6}A$ to ${\sim}2.3\;{\times}\;10^{-6}A$ in the infrared range. The fabricated surface texturing of photo-transistors may be applied for high-efficiency photovoltaic devices.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.67-68
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• 2003

Native corn starch and montmorillonite caly nanocomposites were prepared using the glycerol as the plasticizer. These were characterized by mechanical analysis, X-ray diffraction, infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. The tensile strength increased with the clay content to a maximum point and then decreased due to gapping between the two phases. Dispersion of the layered silicate within the starch was verified using X-ray diffraction pattern. Examination of these materials by scanning electron showed that intercalates have good wetting to the starch surface.

• Textile Coloration and Finishing
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• v.9 no.3
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• pp.33-41
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• 1997

Polystyrene microcapsules were prepared by microencapsulation technique of solvent-evaporation. These microcapsules were characterized by Infrared spectroscopy, thermal analysis, scanning electron microscopy, and shape analysis. Fragrant water was used as a core material. Thermal and pH stabilities of polystyrene microcapsules were relatively excellent. And functional finishing on cotton fabric with microcapsules was applied.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.21-30
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• 2021

The purpose of this study is to investigate the antibacterial effects of indocyanine green (ICG) and near-infrared diode lasers on multispecies biofilms. Multispecies biofilms of Streptococcus mutans, Lactobacillus casei and Candida albicans were treated with different irradiation time using photosensitizer ICG and 808 nm near-infrared diode laser. Colony forming unit (CFU) was measured, and qualitative evaluation of biofilm was performed with confocal laser scanning microscopy (CLSM). Temperature measurement was conducted to evaluate photothermal effect. In the groups using ICG and diode laser, reduction in CFU was statistically significant, but the difference in antibacterial effect on L. casei and C. albicans with irradiation time was not significant, and similar results were confirmed with CLSM. Groups with ICG and diode laser showed higher temperature elevation than groups without ICG, and results of measured temperature were similar to the range of hyperthermia. In conclusion, ICG and near-infrared diode laser showed antibacterial effects on multispecies biofilms, but studies on protocol are necessary for clinical application.

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.88-96
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• 2008

Thermal evaporated 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films were deposited to examine the energy saving properties of silicides formed by rapid thermal annealing at temperature ranging from 500 to $1,100^{\circ}C$ for 40 seconds. Thermal evaporated 10 nm-Ni/(70 nm-poly)Si films were also deposited as a reference using the same method for depositing the 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films. A four-point probe was used to examine the sheet resistance. Transmission electron microscopy (TEM) and X-ray diffraction XRD were used to determine cross sectional microstructure and phase changes, respectively. UV-VIS-NIR and FT-IR (Fourier transform infrared spectroscopy) were used to examine the near-infrared (NIR) and middle-infrared (MIR) absorbance. TEM analysis confirmed that the uniform nickel-cobalt composite silicide layers approximately 21 to 55 nm in thickness had formed on the single and polycrystalline silicon substrates as well as on the 25 to 100 nm thick nickel silicide layers. In particular, nickel-cobalt composite silicides showed a low sheet resistance, even after rapid annealing at $1,100^{\circ}C$. Nickel-cobalt composite silicide and nickel silicide films on the single silicon substrates showed similar absorbance in the near-IR region, while those on the polycrystalline silicon substrates showed excellent absorbance until the 1,750 nm region. Silicides on polycrystalline substrates showed high absorbance in the middle IR region. Nickel-cobalt composite silicides on the poly-Si substrates annealed at $1,000^{\circ}C$ superior IR absorption on both NIR and MIR region. These results suggest that the newly proposed $Ni_{50}Co_{50}$ composite silicides may be suitable for applications of IR absorption coatings.

• Plant Journal
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• v.16 no.3
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• pp.47-52
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• 2020

This study investigated the methodologies to enhance the corrosion resistance and the ways to measure for subsea equipment made of aluminum. The methodologies for the anticorrosion were cathodic protection, conversion coating, anodizing and organic coating. The simply analyzed ways to measure the corrosion resistance were Scanning Electron Microscope (SEM), Electrochemical Impedance Spectroscopy (EIS), Glow discharge optical emission spectrum spectroscopy (GD-OES), Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Scanning Vibrating Electrode Technique (SVET), contact angle and interfacial tension. The most widely used tools for increasing the corrosion resistance were the anodizing and the organic coating. Many ways were evenly used to measure corrosion. The methods more frequently utilized were SEM for the surface investigation and the contact angle to evaluate the corrosion resistance.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1043-1048
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• 2012

In this study, activated carbons (ACs) were modified as electrode materials for an electric double layer capacitor (EDLC) by controlling oxygen- and nitrogen-containing functional groups. The morphological and chemical properties of ACs were analyzed through scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectrometer, automatic elemental analyzer (EA) and Boehm titration. Also, charge/discharge tests were performed to investigate the EDLC performance. Oxygen- and nitrogen-containing functional groups were introduced on the surface of ACs through acid and urea treatments, respectively. ACs with nitrogen-containing functional groups showed 2 mA increase of gravimetric discharge capacity and quick achievement of maximum charge/discharge performance. However, ACs with oxygen-containing functional groups showed low discharge capacity and its gradual decrease during further cyclic test, since the functional groups interrupted adsorption/desorption of charges in the electrolyte on the surface of ACs.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.780-783
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• 2013

Recently, it has been reported that low molecular weight laminarin had the enhanced biological activities. In this study, molecular structure of low molecular weight laminarin prepared by ionizing irradiation was studied. Low molecular weight laminarin samples of 13.5, 8.5, 7, and 6 kDa were obtained from 15 kDa laminarin by irradiation. From gel permeation chromatography data, low molecular weight laminarin was shown to have low polydispersity. To define the changes of functional groups in laminarin with different molecular weights, Fourier-transform infrared analysis was carried out. There was found no significant changes of functional groups in low molecular weight laminarin, except the increase of carbonyl group. The granular fissures from scanning electron microscopy showed the breakage of glycosidic bond in low molecular weight laminarin. These results could be utilized for the investigation of the enhanced biological activities of low molecular weight polysaccharides including laminarin.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.854-860
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• 2017

PSf/D2EHPA/CNTs beads were prepared by immobilizing extractant di-(2-ethylhexyl)- phosphoric acid (D2EHPA) and adsorbent carbon nanotubes (CNTs) on polysulfone (PSf), and the adsorption characteristics of Sr(II) on the beads were studied. The morphological characteristics of the prepared PSf/D2EHPA/CNTs beads were observed by scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), and Fourier transform infrared spectrometer (FTIR). The equilibrium time for the removal of Sr(II) by PSf/D2EHPA/CNTs beads was 60 min. The experimental kinetic data followed pseudo-second-order model more than pseudo-first-order kinetics model. The maximum removal capacity of Sr(II) obtained from Langmuir isotherm was 4.75 mg/g. The removal efficiencies of Sr (II) by PSf/D2EHPA/CNTs beads were improved 2.5 times by adding the adsorbent CNTs more than by using only the extractant D2EHPA.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.644-649
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• 2011

Polyaniline/$SiO_2$ catalyzed one-pot mannich reaction of acetophenone, aromatic aldehydes and aromatic amines are carried out in ethanol to afford various ${\beta}$-amino ketones. The various wt% of polyaniline were supported on pure silica synthesized by using chemical oxidative method. The catalyst prepared has been characterized by means of thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FT-IR). Solvent stability of catalyst was tested using UV-Visible spectroscopy. This protocol has several advantages such as high yield, simple work up procedure, non-toxic, clean, easy recovery and reusability of the catalyst.