• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.212-215
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• 2002

A superoxide dismutase (SOD)-based superoxide ion $(O_2^-)$ sensor was fabricated by immobilizing SOD on a self-assembled monolayer (SAM) of 3-mercaptopropionic acid (MPA) which was prepared on a gold electrode. The SAM of MPA was found to function as an effective promoter for the electrode reaction of SOD. The amperometric response to $(O_2^-)$ was monitored at 300mV and -100mV vs. Ag/ Agel in 5mM phosphate buffer solution containing $KO_2$. The sensor was proved to have a high sensitivity, selectivity and short response time (<5 s) and negligible interference.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.114-114
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• 2002

Purpose： To know the fate of Gadophrin-2-enhanced areas in hearts with acute reperfused myocardial infarction. Method： The left anterior descending branches of coronary arteries were occluded for 90 min and reperfused for 60 min in 15 rabbits. Then, Gadophrin-2 (0.05 mmol/kg) was injected via ear veins. Short-axial T1-weighted spin echo images and fast cine images were obtained 24 hours after injection of Gadophrin-2. After four weeks, short-axial cine MRI was performed and T1-weighted spin echo Images were obtained 5 min and 15 min after injection of Gd-DTPA (0.2 mmol/kg). The animals were sacrificed and short-axial slices of the specimen were stained with 1.5% triphenyltetrazolium chloride (TTC) solution.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.411-415
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• 2006

In recent years there has been considerable interest in the network GPS RTK surveying. Single RTK has some limit in long distance and it has an accuracy problem depend on the baseline length. The significant improvement of GPS network technology, RTCM V3.0 correction format and telecommunication technology can eliminate the weakness of single GPS RTK. This paper is the practical field result of GPS network RTK.

• Analytical Science and Technology
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• v.17 no.1
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• pp.82-84
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• 2004

The quantitative trace analysis of ions could be deteriorated by filter papers because of the effect of adsorption. Generally the adsorption of anions on filter paper did not occurred. Instead, $Cl^-$ and $NO{_3}^-$ ions were extracted from the filter papers. However, most metal ions were adsorbed on the filter papers by the formation of hydroxide in neutral solution. The adsorption of metal ions except $Ag^+$ ion could be avoided depend on the acid concentrations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.551-552
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• 2006

This study was attended to demonstrate synthesis of silver nanoparticles stabilized with polymer and their applicability to printed electronics. Silver nanoparticles were synthesized by reduction of silver nitrate in aqueous solution in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer. The ink used here is composed of 50 wt% Ag NP, 15 wt% humectant and then were printed on polyimide film. Particle deposit morphologies were controlled by varying the ink compositions. Printed silver patterns and dots were cured on a convection oven in air at $300^{\circ}C$ for 60 min. The printed patterns show good shape definition and the resistivity of the printed films is about $5{\mu}{\Omega}{\cdot}cm$.

• Journal of Auto-vehicle Safety Association
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• v.13 no.3
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• pp.20-25
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• 2021

Flexural resistance evaluation of FFC (Flexible Flat Cable) was performed according to the grain size of rolled copper foil by adding 0.1wt% silver (Ag) and electrodeposited copper foil by slitting method after heat-treatment. These methods are aimed at enhancing the flexural durability of the FFC by growing the grain size of copper foil. By increasing the grain size of the copper foil and minimizing the miss-orientation at grain boundaries, the residual stress at the grain boundaries of the copper foil is reduced and the durability of the FFC is improved. Maximizing an average grain size of copper foil can be got a good solution in order to enhance the durability of the FFC or FPCB (Flexible Printed Circuit Board).

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.1.1-1.1
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• 2011

Printed electronics based on the direct writing of solution processable functional materials have been of paramount interest and importance. In this talk, the synthesis of printable inorganic functional materials (conductors and semiconductors) for thin-film transistors (TFTs) and photovoltaic devices, device fabrication based on a printing technique, and specific characteristics of devices are presented. For printable conductor materials, Ag ink is designed to achieve the long-term dispersion stability and good adhesion property on a glass substrate, and Cu ink is sophisticatedly formulated to endow the oxidation stability in air and even aqueous solvent system. The both inks were successfully printed onto either polymer or glass substrate, exhibiting the superior conductivity comparable to that of bulk one. In addition, the organic thin-film transistor based on the printed metal source/drain electrode exhibits the electrical performance comparable to that of a transistor based on a vacuum deposited Au electrode. For printable amorphous oxide semiconductors (AOSs), I introduce the noble ways to resolve the critical problems, a high processing temperature above $400^{\circ}C$ and low mobility of AOSs annealed at a low temperature below $400^{\circ}C$. The dependency of TFT performances on the chemical structure of AOSs is compared and contrasted to clarify which factor should be considered to realize the low temperature annealed, high performance AOSs. For photovoltaic application, CI(G)S nanoparticle ink for solution processable high performance solar cells is presented. By overcoming the critical drawbacks of conventional solution processed CI(G)S absorber layers, the device quality dense CI(G)S layer is obtained, affording 7.3% efficiency CI(G)S photovoltaic device.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.351-357
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• 2003

Transuranic elements such as Pu, Am and Cm in synthetic solution of spent nuclear fuel samples were determined by electrodeposition followed by alpha-spectrometry after separation using anion exchange and extraction chromatography in order to determine the transuranic elements in radwaste samples from nuclear power plants. Plutonium was separated by 12M HC1-0.1M HI as an eluent on anion exchange column. As a second step Am and Cm were separated in a group by DTPA-Lactic acid as the eluent on HDEHP coated column. The nuclides of $^{239}Pu$, $^{241}Am$및 $^{244}Cm$ separated were determined by alpha-spectrometry after electrodeposition in 0.1M $NaHSo_4$-0.53M $Na_2SO_4$buffer solution as an electrolyte. The recovery yields of $^{239}Pu$, $^{241}Am$및 $^{244}Cm$ were 83.8%, 85.2% and 86.3%, respectively, from the synthetic solution containing uranium and non-radioactive metal elements.

• Journal of the Korean institute of surface engineering
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• v.49 no.3
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• pp.301-306
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• 2016

The effects of nanotexturing and post-etching on the reflection and quantum efficiency properties of diamond wire sawn (DWS) multicrystalline silicon (mc-Si) solar cell have been investigated. The chemical solutions, which are acidic etching solution (HF-$HNO_3$), metal assisted chemical etching (MAC etch) solutions ($AgNO_3$-HF-DI, HF-$H_2O_2$-DI) and post-etching solution (diluted KOH at $80^{\circ}C$), were used for micro- and nano-texturing at the surface of diamond wire sawn (DWS) mc-Si wafer. Experiments were performed with various post-etching time conditions in order to determine the optimized etching condition for solar cell. The reflectance of mc-Si wafer texturing with acidic etching solution showed a very high reflectance value of about 30% (w/o anti-reflection coating), which indicates the insufficient light absorption for solar cell. The formation of nano-texture on the surface of mc-Si contributed to the enhancement of light absorption. Also, post-etching time condition of 240 s was found adequate to the nano-texturing of mc-Si due to its high external quantum efficiency of about 30% at short wavelengths and high short circuit current density ($J_{sc}$) of $35.4mA/cm^2$.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3208-3212
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• 2012

Controlled drug delivery systems employing microparticles offer lots of advantages over conventional drug dosage formulations. Microencapsulation technique have been conducted with biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) and poly(lactic acid) (PLA) for its adjustable biodegradability and biocompatibility. In this study, we evaluated two techniques, oil-in-water (o/w) emulsion solvent evaporation and spray drying, for preparation of polymeric microparticles encapsulating a newly synthesized drug, SS-AG20, for the long-term drug delivery of this low-molecular-weight drug with a very short half-life. Drug-loaded microparticles prepared by the solvent evaporation method showed a smoother morphology; however, relatively poor encapsulation efficiency and drastic initial burst were discovered as drawbacks. Spray-dried drug-loaded microparticles had an imperfect surface with pores and distorted portions so that its initial burst was critical (70.05-87.16%) when the preparation was carried out with a 5% polymeric solution. By increasing the concentration of the polymer, the morphology was refined and undesirable initial burst was circumvented (burst was reduced to 35.93-74.85%) while retaining high encapsulation efficiency. Moreover, by encapsulating the drug with various biodegradable polymers using the spray drying method, gradual and sustained drug release, for up to 2 weeks, was achieved.