• Food Science and Preservation
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• v.15 no.2
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• pp.236-242
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• 2008

We investigated the optimum concentration of a $NaClO_2$ solution and the amount of gaseous $Cl_2$ for production of high yield and purity of aqueous $ClO_2$ by use of a gaseous chlorine-chlorite $ClO_2$ generator. This system produced lower concentrations of chlorine dioxide and is applicable for direct-use in food processing as a cleaner and sanitizer. The concentration of $NaClO_2$ solution and the amount of gaseous $Cl_2$ was varied from 0.01-0.1% and 100-1,000 g/hr, respectively. The concentrations of chlorite, chlorate, FAC (free available chlorine), and chlorine dioxide that were produced increased with increasing concentration of $NaClO_2$ solution and with the amount of gaseous $Cl_2$. The optimum concentration of $NaClO_2$ solution and amount of gaseous $Cl_2$ were 0.1% and 900 g/hr respectively. $ClO_2$ and FAC produced at these concentrations were 882.0 ppm and 8.0 ppm, with no detection of chlorite and chlorate. The yield and purity of $ClO_2$ were 97.0% and 96.0% respectively. Immersion-cleaning experiments showed that this protocol decreased the level of CFU/g by $10^3$- to $10^4$-fold, with a similar effect on fruit.

• Textile Coloration and Finishing
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• v.5 no.4
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• pp.29-41
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• 1993

In order to surface Hydrophobilization of Poly(ethylene terephthalate) (PET) fiber samples were treated in the atmosphere of CF$_{4}$ or $C_{2}$F$_{6}$glow discharge. The sample used in this study was PET film which is 75$\mu$m thick made by Teijin, O-Type(Japan). The cleaned samples were placed in plasma reactor made of pyrex glass cylinder, and plasma processing was carried out by glow discharge of CF$_{4}$ or $C_{2}$F$_{6}$ gas, being continuously fed by gas flow and continuously pumped out by a vacuum system. Electric power source for generate plasma state was sustained alternating current(60Hz) and voltage was sustained 600 volt. The duration of plasma treatment varied from 15 to 120 seconds except special case, the monomer gase pressure varied from 0.02 to 0.3 Torr and power range was 10 to 90 watts. The hydrophobic features of changed PET surface were evaluated by contact angle measurement and surface chemical characteristics were analyzed by ESCA. Results can be summerized as follows. 1. The most favorable setting position of substrate was the center area between the two electrodes. 2. $C_{2}$F$_{6}$ discharge current was lower than that of CF$_{4}$ when same voltage was sustained. Treated efficiency between CF$_{4}$ and $C_{2}$F$_{6}$ did not revealed significant differences under same electric power(wattage). 3. When monomer pressure is very low below 0.02 torr, as though substrate is exposed to CF$_{4}$ or $C_{2}$F$_{6}$ plasma, it tend to be hydrophilic through a little of fluorine bond and a great deal of oxidizing reaction. 4. There brought good hydrophobilization when monomer pressure was more 0.1 torr and duration of glow discharge treatment was over 45 seconds. When monomer pressure was too high, discharge current became low. Although prolong the duration, there was no more high hydrophobilization. 5. According to ESCA analysis, there were a little CF bond and a prevailing CF$_{2}$ bond in CF$_{4}$-treated substrate. There were CF$_{3}$, a little CF and a prevailing CF$_{2}$ bond in $C_{2}$F$_{6}$-treated substrate.d substrate.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.131-131
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• 2013

A single-layer graphene has been uniformly grown on a Cu surface at elevated temperatures by thermally processing a poly(methyl methacrylate) (PMMA) film in a rapid thermal annealing (RTA) system under vacuum. The detailed chemistry of the transition from solid-state carbon to graphene on the catalytic Cu surface was investigated by performing in-situ residual gas analysis while PMMA/Cu-foil samples being heated, in conjunction with interrupted growth studies to reconstruct ex-situ the heating process. The data clearly show that the formation of graphene occurs with hydrocarbon molecules vaporized from PMMA, such as methane and/or methyl radicals, as precursors rather than by the direct graphitization of solid-state carbon. We also found that the temperature for vaporizing hydrocarbon molecules from PMMA and the length of time the gaseous hydrocarbon atmosphere is maintained, which are dependent on both the heating temperature profile and the amount of a solid carbon feedstock are the dominant factors to determine the crystalline quality of the resulting graphene film. Under optimal growth conditions, the PMMA-derived graphene was found to have a carrier (hole) mobility as high as ~2,700 cm2V-1s-1 at room temperature, superior to common graphene converted from solid carbon.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.143-150
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• 2012

A simulation methodology and corresponding program based on it is to be discussed for analyzing the effects of the networking operation of existing DHC system in connection with CHP system on-site. The practical simulation for arbitrary areas with various building compositions is carried out for the analysis of operational features in both systems, and the various aspects of thermal energy grids with connecting operation are highlighted through the detailed assessment of predicted results. The intrinsic operational features of CHP prime movers, gas engine, gas turbine etc., are effectively implemented by realizing the performance data, i.e. actual operation efficiency in the full and part loads range. For the sake of simplicity, a simple mathematical correlation model is proposed for simulating various aspects of change effectively on the existing DHC system side due to the connecting operation, instead of performing cycle simulations separately. The empirical correlations are developed using the hourly based annual operation data for a branch of the Korean District Heating Corporation (KDHC) and are implicit in relation between main operation parameters such as fuel consumption by use, heat and power production. In the simulation, a variety of system configurations are able to be considered according to any combination of the probable CHP prime-movers, absorption or turbo type cooling chillers of every kind and capacity. From the analysis of the thermal network operation simulations, it is found that the newly proposed methodology of mathematical correlation for modelling of the existing DHC system functions effectively in reflecting the operational variations due to thermal energy grids with connecting operation. The effects of intrinsic features of CHP prime-movers, e.g. the different ratio of heat and power production, various combinations of different types of chillers (i.e. absorption and turbo types) on the overall system operation are discussed in detail with the consideration of operation schemes and corresponding simulation algorithms.

• Korean Journal of Materials Research
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• v.20 no.11
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• pp.570-574
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• 2010

A diamond-like carbon (DLC) film deposited on a WC disk was investigated to improve disk wear resistance for injection molding of zirconia optical ferrule. The deposition of DLC films was performed using the filtered vacuum arc ion plating (FV-AIP) system with a graphite target. The coating processing was controlled with different deposition times and the other conditions for coating, such as input power, working pressure, substrate temperature, gas flow, and bias voltage, were fixed. The coating layers of DLC were characterized using FE-SEM, AFM, and Raman spectrometry; the mechanical properties were investigated with a scratch tester and a nano-indenter. The friction coefficient of the DLC coated on the WC was obtained using a pin-on-disk, according to the ASTM G163-99. The thickness of DLC films coated for 20 min. and 60 min. was about 750 nm and 300 nm, respectively. The surface roughness of DLC films coated for 60 min. was 5.9 nm. The Raman spectrum revealed that the G peak of DLC film was composed of $sp^3$ amorphous carbon bonds. The critical load (Lc) of DLC film obtained with the scratch tester was 14.6 N. The hardness and elastic modulus of DLC measured with the nano-indenter were 36.9 GPa and 585.5 GPa, respectively. The friction coefficient of DLC coated on WC decreased from 0.2 to 0.01. The wear property of DLC coated on WC was enhanced by a factor of 20.

• Polymer(Korea)
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• v.24 no.4
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• pp.529-537
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• 2000

The effects of the gel content on the cell structures of PP sheets by using an electron-curing system were investigated. Three extruded PP sheets crosslinked by three different doses were used for the batch foaming process with the supercritical state $CO_2$. Experiments were also performed in order to study the effects of the gel content, saturation pressure and temperature on cell structures. Then foaming conditions, such as temperature and duration of time, were changed. The amount of gas absorbed into PP samples was not affected by gel contents and the operating condition of saturation pressure, which was higher than 2000 psi. The foam cells of PP with a low gel content grew irregularly at a higher foaming temperature and for a longer duration of foaming time. However, PP samples with high gel content showed even cell structures and narrow tell size distributions under the severe conditions of high foaming temperatures and long duration of foaming time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.208-208
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• 2010

Indium zinc tin oxide (IZTO) thin films were studied as a possible alternative to indium tin oxide (ITO) films for providing low-cost transparent conducting oxide (TCO) for thin film photovoltaic devices. IZTO films were deposited onto glass substrates at room temperature. A dc/rf magnetron co-sputtering system equipped with a ceramic target of the same composition was used to deposit TCO films. Earlier studies showed that the resistivity value of $In_{0.6}Zn_{0.2}Sn_{0.2}O_{1.5}$ (IZTO20) films could be lowered to approximately $6{\times}10^{-4}ohm{\cdot}cm$ without sacrificing optical transparency and still maintaining amorphous structure through the optimization of process variables. The growth rate was kept at about 8 nm/min while the oxygen-to-argon pressure ratio varied from 0% to 7.5%. As-deposited films were always amorphous and showed strong oxygen pressure dependence of electrical resistivity and electron concentration values. Influence of forming gas anneal (FGA) at medium temperatures was also studied and proven effective in improving electrical properties. In this study, the chemical composition of the targets and the films varied around the $In_{0.6}Zn_{0.2}Sn_{0.2}O_{1.5}$ (IZTO20). It was the main objective of this paper to investigate how off-stoichiometry affected TCO characteristics including electrical resistivity and optical transmission. In addition to the composition effect, we have also studied how film properties changed with processing variables. IZTO thin films have shown their potential as a possible alternative to ITO thin films, in such way that they could be adopted in some applications where currently ITO and IZO thin films are being used. Our experimental results are compared to those obtained for commercial ITO thin films from solar cell application view point.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.499-504
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• 2010

It is important to determine the exact soot mass in a DPF system in order to control the timing of PM regeneration. The soot mass accumulated in a filter can be estimated from the pressure drop in the filter and the exhaust gas flow rates. In this study, the soot index is defined as the pressure drop in the DPF divided by the pressure drop in a DOC. An effective signal processing method for determining the soot index is proposed; the results yielded by this method indicate good correlation between the soot index and the amount of soot loaded into the filter for both steady-state and transient-state operating conditions in a 3L diesel engine for passenger vehicles.

• Journal of Veterinary Clinics
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• v.17 no.2
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• pp.359-367
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• 2000

The aim of this study was to evaluate the effects of propofol on cortical electroencephalogram (EEG) in seven dogs. Propofol infusion was accomplished from low concentration to high concentration in series, and each concentration was infused for 20 minutes (M0: 0, M0.5: 0.5, M1.0:1.0, and M1.5: 1.5 mg/kg/min of infusion rate). EEG was recorded via needle electrode placed at Cz, which was applied to International 10-20 system. Arterial blood pressure. blood gas analysis and ECG were also measured. Hoemodynamics, Pa$CO_2$, PaO$_2$, heart rate and respiratory rate were variable, but were net significant(p>0.05). The power spectra of EEG in every concentration was compared wish those of control (MO). The powers at a1l frequencies at M1.0 and Ml.5 were decreased. Especially, the powers of the frequencies over 20 Hz were significantly decreased (p<0.O5). Powers at frequencies between 8 and 15Hz at MO.S were significantly increased (p<0.05) in response to the painful stimuli. It was inferred that they may reflect activity of the brain which is consciously processing the external Stimuli. Like the Power spectra, al1 the band powers of He EEG ($\delta$ 1-4, $\theta$4-8, $\alpha$ 8-13, $\beta$L13-21. $\beta$H 21-30, \ulcorner 30-50, and total 1-5OHz) were decreased in proportion to the increase of infusion rate at M1 .0 and M1.5. Especially, decrease of $\beta$H and ${\gamma}$ were significant(p<0.01). At M0.5, $\alpha$ band was significantly increased(p<0.05) among all the bands. Seizure activities which were concide with occurrence of spike wave were shown in all dogs at Ml .0 and M1.5.

• Journal of the Korean institute of surface engineering
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• v.49 no.6
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• pp.604-611
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• 2016

In order to comply with demand for high efficient gas turbines operating at higher temperatures, considerable amounts of research efforts have been performed with searching for the next-generation thermal barrier coatings (TBCs) with respect to coating materials as well as processing methods. In this study, thermal barrier coatings in the $(La_{1-x}Gd_x)_2Zr_2O_7$ system, which is one of the most versatile materials replacing yttria-stabilized zirconia (YSZ), are fabricated by suspension plasma spray with suspension made of synthesized powders via solidstate reaction. Dense, $100{\sim}400{\mu}m$ thick coatings of fluorite-phase zirconate with moderate amount of segmented microstructures are obtained by using suspension plasma spray. Phase formation and thermal diffusivity are characterized with coating compositions. The feasibility of $(La_{1-x}Gd_x)_2Zr_2O_7$ coatings for TBC applications is also discussed.