• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.25.2-25.2
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• 2011

Recently, thin film capacitors used for vehicle inverters are small size, high capacitance, fast response, and large capacitance. But its applications were made up of liquid as electrolyte, so its capacitors are limited to low operating temperature range and the polarity. This research proposes using Ni-P alloys by electroless plating as the electrode instead of liquid electrode. Our substrate has a high aspect ratio and complicated shape because of anodic aluminum oxide (AAO). We used AAO because film thickness and effective surface area are depended on for high capacitance. As the metal electrode instead of electrolyte is injected into AAO, the film capacitor has advantages high voltage, wide operating temperature, and excellent frequency property. However, thin film capacitor made by electroless-plated Ni on AAO for full-filling into etched tunnel was limited from optimizing the deposition process so as to prevent open-through pore structures at the electroless plating owing to complicated morphological structure. In this paper, the electroless plating parameters are controlled by temperature in electroless Ni plating for reducing reaction rate. The Electrical properties with I-V and capacitance density were measured. By using nickel electrode, the capacitance density for the etched and Ni electroless plated films was 100 nFcm-2 while that for a film without any etch tunnel was 12.5 nFcm-2. Breakdown voltage and leakage current are improved, as the properties of metal deposition by electroless plating. The synthesized final nanostructures were characterized by scanning electron microscopy (SEM).

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.455-460
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• 1986

Dane particle was prepared from the plasma of chronic HBsAg carrier with high levels of HBsAg activity. DNA extracted front Dane particle core after a DNA polymerase reaction with $\alpha$-($^{32}$P) dNTP, was identified as HBV DNA by liquid scintillation counter and agarose gel electrophoresis-G.M. counting. To produce Hepatitis B surface antigen for use as a vaccine against Hepatitis B virus infection, yeast strains harboring recombinant plasmid with Apase promoter was used. Recombinant plasmid was construced from pHBV 130 and pAN 82, transformed into E coli, and then transferred into yeast strains. HBsAg was produced by derepression in Burkholder minimal medium with controlled inorganic phosphate concentration. The kinetics of HBsAg production was also investigated. Total HBsAg activity increased rapidly between 3 and 6 hours after transfer to phosphate-free medium and reached a maximum at around 9th hour. The transfer into phosphate-free medium after 6 hours in high phosphate cell growth medium gave maximum activity.

• Journal of The Korean Dental Society of Anesthesiology
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• v.12 no.2
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• pp.105-109
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• 2012

The gag reflex is a physiological reaction, but, an exaggerated gag reflex can be a severe limitation not only to treat dental caries but also to do oral exam. Procedures such as surface anesthesia of the palate and pharyngeral area, sedation, or general anesthesia can be options as behavioral management. But, there are no golden rule for the sever gag reflex patients. We present a case report of propofol intravenous sedation using TCI pump for simple dental treatment. A 44-year-old man, who had past history of general anesthesia for dental treatment because of severe gag reflex, was scheduled intravenous sedation for simple dental treatment. After 8 hour fasting he entered the clinic for persons with disabilities. We explained about intravenous deep sedation and got informed consent. First, we kept intravenous catheter (22G) in the arm and started monitoring ECG, non-invasive blood pressure, pulse oximetry and end-tidal $CO_2$ through nasal cannula. We started propofol infusion with TCI pump at the target concentration of 3 mcg/ml. The patient became sedated, but he showed involuntary movement during dental treatment, so we increased the target concentration to 4 mcg/ml. We finished the dental treatment without complications during 30 min. And after 40 min recovery room stay he was discharged without any complications.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.325-329
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• 2016

In this study, we investigated the feasibility of using printed Indium Tin Oxide (ITO) film as a remote sensor for Hazardous and Noxious Substances (HNS). To improve the quality of the ITO films, binder mixing ratio, Sn concentration in ITO, thermal treatment temperature, and printing process conditions were optimized. We fabricated an electrical resistance-type liquid sensor, and to confirm the sensor operation, the change in resistance in air and seawater was monitored. The change in resistance of the ITO sensor was explained in terms of reduction reaction on the surface. Further, the sensor was controlled by Arduino, and the remote data acquisition was demonstrated.

• Korean Journal of Materials Research
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• v.22 no.5
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• pp.243-248
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• 2012

ZrN nanoparticles were prepared by an exothermic reduction of $ZrCl_4$ with $NaN_3$ in the presence of NaCl flux in a nitrogen atmosphere. Using a solid-state combustion approach, we have demonstrated that the zirconium nitride nanoparticles synthesis process can be completed in only several minutes compared with a few hours for previous synthesis approaches. The chemistry of the combustion process is not complex and is based on a metathesis reaction between $ZrCl_4$ and $NaN_3$. Because of the low melting and boiling points of the raw materials it was possible to synthesize the ZrN phase at low combustion temperatures. It was shown that the combustion temperature and the size of the particles can be readily controlled by tuning the concentration of the NaCl flux. The results show that an increase in the NaCl concentration (from 2 to 13 M) results in a temperature decrease from 1280 to $750^{\circ}C$. ZrN nanoparticles have a high surface area (50-70 $m^2/g$), narrow pore size distribution, and nano-particle size between 10 and 30 nm. The activation energy, which can be extracted from the experimental combustion temperature data, is: E = 20 kcal/mol. The method reported here is self-sustaining, rapid, and can be scaled up for a large scale production of a transition metal nitride nanoparticle system (TiN, TaN, HfN, etc.) with suitable halide salts and alkali metal azide.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.416-423
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• 1996

Electrochemical reduction of thionyl chloride in 1.5 M $LiAlCl_4/SOCl_2$ electrolyte solution containing tetradentate Schiff base Co(II), Ni(II), Cu(II), and Mn(II) complexes has been investigated at the glassy carbon electrode. The catalyst molecules of transition metal(II) complexes were adsorbed on the electrode surface and reduced thionyl chloride resulting in a generation of oxidized catalyst molecules. There was an optimum concentration for each catalyst compound. The current density of $SOCl_2$ reduction was enhanced up to 150% at the catalyst contained electrolyte solution. The reduction currents of thionyl chloride were increased and the reduction potentials were shifted to the negative potential as scan rates became faster. The reduction of thionyl chloride was proceeded to diffusion controlled reaction.

• Macromolecular Research
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• v.17 no.7
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• pp.491-498
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• 2009

New $\pi$-conjugated multi-branched molecules were synthesized through the Homer-Emmons reaction using alkyl-substituted, 3,4-ethylenedioxythiophene-based, thiophenyl aldehydes and octaethyl benzene-l,2,4,5-tetrayltetrakis(methylene) tetraphosphonate as the core unit; these molecules have all been fully characterized. The two multi-branched conjugated molecules exhibited excellent solubility in common organic solvents and good self-film forming properties. The semiconducting properties of these multi-branched molecules were also evaluated in organic field-effect transistors (OFET). With octyltrichlorosilane (OTS) treatment of the surface of the $SiO_2$ gate insulator, two of the crystalline conjugated molecules, 7 and 8, exhibited carrier mobilities as high as $2.4({\pm}0.5){\times}10^{-3}$ and $1.3({\pm}0.5){\times}10^{-3}cm^2V^{-1}s^{-1}$, respectively. The mobility enhancement of OFET by light irradiation ($\lambda$ = 436 nm) supported the promising photo-controlled switching behavior for the drain current of the device.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.405-410
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• 2011

A study on chemical vapor deposition(CVD) of $WO_3$ and the electrochromic properties of the CVD $WO_3$ films have been carried out. The crystalinity, purity, and growth rate of the films depending on substrate temperatures are investigated. The highest growth rate is $8{\mu}m/min$ at the substrate temperatures above $300^{\circ}C$ and the estimated activation energy for overall film growth is about 45.9 kJ/mol at the temperatures of $225{\sim}275^{\circ}C$, where the CVD process is controlled by a surface reaction kinetics. The films grown below $275^{\circ}C$ are amorphous, while those deposited above $300^{\circ}C$ are crystalline. The effects of thickness and deposition temperature of the $WO_3$ films on electrochromic activity are also investigated. The coloration efficiency of the films increases with increase in film thickness and decrease in deposition temperature.

• Clean Technology
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• v.21 no.1
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• pp.62-67
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• 2015

We have developed a versatile method for the preparation of chemically linked graphene/multi-walled carbon nanotubes (MWNTs) hybrid materials via simple acid-catalyzed dehydration reaction between graphene oxide (GO) and amine-functionalized MWNTs (af-MWNTs). In this condition, ketone (-C=O) groups in GO and primary amine (-NH₂) moieties in af-MWNTs readily react to form imine (-C=N-) linkage. The chemical structures of graphene/MWNTs hybrid materials have been investigated using various microscopic and spectroscopic measurements. As a result of the synergetic effects of hybrid materials such as improved surface area and the superior structural restoration of graphitic networks, the hybrid materials demonstrate improved capacitance with excellent long-term stability. Furthermore, controlled experiments were conducted to optimize the weight ratio of graphene/MWNTs in hybrid materials. The highest capacitance of 132.4 F/g was obtained from the GM7.5 material, in which the weight ratio between graphene and MWNTs was adjusted to 7.5/1, in 1M KOH electrolyte at a scan rate of 100 mV/s.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.2
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• pp.131-157
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• 2016

A smog chamber has been an effective tool to study air quality, particularly secondary organic aerosol (SOA), which is typically formed by atmospheric oxidation of volatile organic compounds (VOCs). In controlled environments, smog chamber studies have validated atmospheric oxidation by identifying, quantifying and monitoring products with state-of-art instruments (e.g., aerosol mass spectrometer, scanning mobility particle sizer) and provided chemical insights of SOA formation by elucidating reaction mechanisms. This paper reviews types of smog chambers and the current state of smog chamber studies that have accomplished to find pathways of SOA formation, focusing on gas-particle partitioning of semivolatile products of VOC oxidation, heterogeneous reactions on aerosol surface, and aqueous chemistry in aerosol waters (e.g., cloud/fog droplets and wet aerosols). For future chamber studies, then, this paper discusses potential formation pathways of fine particles that East Asia countries (e.g., Korea and China) currently suffer from due to massive formation that gives rise to fatal health problems.