• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.58-64
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• 2006

Recently deep interests have been paid on the effective generation of ozone, which has been widely used for water treatment, deodorization, color removal, and chemical processing of exhausted smoke. The silent discharge reaction has been proposed as the most effective one in the many ozone generation methods, because the silent discharge can be generated under the conditions of lower applied voltage and power consumption, compared other ones. In this paper, in order to improve the ozone generation and ozone generation efficiency, the conventional silent discharge chamber with $Al_2O_3$ dielectric layer and tubular ferroelectric bed discharge reactor packed with $Al_2O_3$ pellets were made, and the silent discharge of the reactors were studied experimentally. The ozone generation characteristics are also discussed based on the discharge characteristics, especially on the wall charge accumulation properties and power consumption. The results show that the electric charges of discharge tube with bead are around 2.5 times as large as those without bead. In the discharge chamber packed with dielectric beads, the ozone concentration and the energy yield characteristics were also improved, compared with those in the conventional silent discharge reactor.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.2
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• pp.37-45
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• 1995

The performance and the operational problems of UASB(Upflow Anaerobic Sludge Blanket) reactor for treatment of dairy wastewaters were investigated. Synthetic milk wastewater was successfully treated up to the loading rate of 3.9kg $COD/m^3.day$, with a specific gas production rate of 1. 23 I/I. day and a COD removal efficiency of over 90%. However, the sludge rising was observed at the loading rate of 2.1kg $COD/m^3.day$, due probably to the formation of scum layer at the surface of settling compartment. The BMP(biochemical methane potential) of raw milk wastewater and ice cream wastewater, measured by using SBT(serum bottle test), were 0.135 and 0.66ml $CH_4/mg\;COD_{added}$, respectively. The sludge activity increased more than 8 times from 0.159g $COD-CH_4/g$ VSS. d during 90 days of operation.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1297-1303
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• 2020

In this study, nuclear radiation shielding and rigidity parameters of Y (0.1-x)B0.6Bi1.8O3La2x glassy system were investigated in order to determine it's suitability for use as nuclear radiation shielding materials. Therefore, a group of bismuth borate glass samples with La₂O₃ additive were synthesized using the technique of melt quenching. According to the results, the increase of the La₂O₃ additive increases the density of the glass samples and the mass attenuation coefficient (μ_m) values, whereas the half-value layer (HVL) and mean free path (MFP) values decrease. The effective atomic number (Z_eff) is also enhanced with an increment of both mass removal cross section for neutron (Σ_R) and absorption neutron scattering cross section (σ_abs). In addition to the other parameters, rigidity parameter values were theoretically examined. The increase of La₂O₃ causes some other important magnitudes to increase. These are the average crosslink density, the number of bonds per unit volume, as well as the stretching force constant values of these glass samples. These results are in concordance with the increase of elastic moduli in terms of the Makishima-Mackenzie model. This model showed an increase in the rigidity of the glass samples as a function of La₂O₃.

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.287-294
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• 2009

Desalination effects of Capacitive deionization(CDI) process using activated carbon $TiO_2$ composite electrode. In this study, we made the activated carbon electrod and activated carbon $TiO_2$ composite electrode, which analysed at cyclic voltammetry and charge-discharge. The results measured for discharge capacitance in cyclic voltammetry were 125 F/g in activated carbon electrode and capacitance of activatd carbon composite electrode was increased about two time, 243 F/g. The $TiO_2$ content of activated carbon composite electrode was 10 wt.%. When it was added wtih TiO2, electric double layer adsorption content was increased, so it was increased 25% in ion removal ratio of activated carbon electrode.

• Transactions on Electrical and Electronic Materials
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• v.8 no.1
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• pp.5-10
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• 2007

Using a reference slurry, ammonium dodecyl sulfate (ADS), an anionic and environmentally friendly surfactant, was investigated as an alternative to BTA for its inhibition and lubrication characteristics. Results demonstrated that the inhibition efficiency of ADS was superior to that of BTA. Coefficient of friction (COF) was the lowest when the slurry contained ADS. This suggested that adsorbed ADS on the surface provided lubricating action thereby reducing the wear between the contacting surfaces. Temperature results were consistent with the COF and removal rate data. ADS showed the lowest temperature rise again confirming the softening effect of the adsorbed surfactant layer and less energy dissipation due to friction. Spectral analysis of shear force showed that increasing the pad-wafer sliding velocity at constant wafer pressure shifted the high frequency spectral peaks to lower frequencies while increasing the variance of the frictional force. Addition of ADS reduced the fluctuating component of the shear force and the extent of the pre-existing stick-slip phenomena caused by the kinematics of the process and collision event between pad asperities with the wafer. By contrast, in the case of BTA, there were no such observed benefits but instead undesirable effects were seen at some polishing conditions. This work underscored the importance of real-time force spectroscopy in elucidating the adsorption, lubrication and inhibition of additives in slurries in CMP.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.549-560
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• 2006

Purpose : This experiment examined the effects of anodization on commercially pure titanium implant fixtures. Material & methods : The implant fixtures were anodized at three different voltage levels, producing three different levels of oxidation on the surface of the fixure. Implant were divided into four groups according to the level of oxidation. Group 1 consist of the control group of machined surface implants, Group 2 implants were treated by anodizing to 100 voltage, Group 3 implants were treated by anodizing oxidation to 200 voltage Group 4 implants were treated by anodizing oxidation to 350 voltage. Surface morphology was observed by Scanning Electron Microscope(SEM) and the surface roughness was measured using NanoScan $E-1000^{\circledR}$. Implantation of the fixtures were performed using New Zealand white rabbits. $Periotest^{\circledR}$ value(PTV) resonance frequency analysis(RFA), and removal torque were measured in 0, 2, 4, 8, 12 weeks after implantation. Results : The results of the study were as follows: 1. Values for the measured surface roughness indicate statistically significant differences in Ra, Rq, and Rt values among group 1, 2, 3, and 4 at the top portion of the thread,(p<0.05) while values at the base of the threads indicated no significant difference in these values. 2. A direct correlation between the firming voltage, and surface roughness and irregularities were observed using scanning electron microscope. 3. No statistically significant differences were found between test groups regarding $Periotest^{\circledR}$ values. 4. Analysis of the data produced by RFA, significant differences were found between group 1 and group 4 at 12 weeks after implantation.(p<0.05) Conclusions : In conclusion, no significant differences could be found among test groups up to a certain level of forming voltage threshold, beyond this firming voltage threshold, statistically significant differences occurred as the surface area of the oxide layer increased with the increase in surface porosity, resulting in enhanced bone response and osseointegration.

• Korean Journal of Veterinary Research
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• v.34 no.4
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• pp.787-799
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• 1994

To elucidate morphologic lesion of porcine exudative epidermitis which is occurred sporadically in Korea, Staphylococcus hyicus subsp. hyicus isolated from the naturally affected pigs was inoculated to suckling pigs. The infected piglets were observed grossly and histopathologically. Although affected piglets were taking acute, subacute, or chronic course, some piglets suffered from chronic disease showed poor prognosis and marked growth depression. Affected peglets had erythematous skin on the face, ear, and abdomen and these localized lesions appear as brownish spots of exudative epidermitis and fromed crust in the early stage. But, after this stage, the skin were covered by viscous greasy exudate and formed blackish brown crust and appeared fissures and hypertrophy. Grossly, there has been hemorrhage with the removal of crust-like materials of epidermis and edematous subcutis. The superficial lymph nodes were edematous and swollen or congested and hemorrhagic. Some piglets had swollen ureters, cysts in the renal cortex, or polyarthritis. A few cases had mild edematous swelling of kidney, intestinal catarrh and congestion of brain. Microscopically, skin lesions had detachment of keralinized layer and parakeratosis of epidermis, hydropic degeneration of epidermal cell, and retrogressive degeneration of hair root sheath. Dermis had edema, and infiltration of neutrophils and mononuclear cells. As the disease was proceeded, there was marked perivasculitis with lots of mononuclear inflammatory cells. More chronic lesions formed granuloma-like bodies(nodules) due to more mononuclear, perivascular inflammatory cell infiltration and proliferation of fibroblast. Lots of plasma cells and eosinophils were also present in dermis. Epidermis was hyperplastic by proliferation of basal cells stratum germinativum and epidermal pegs often extended into the dermis. In secondary infection, lots of neutrophils could be seen in epidermis and derms. Kidney had neutrophilic infiltration, necrotic and cystic glomeruli, and dilation of renal tubules and ureters. Purulent arthritis was sometimes observed in joints. Three days old mice administrated Staphylococcus hyicus subsp hyicus subcutaneously before had focal congestion and hemorrhage, necrosis, and subcutaneous edema of the skin. This observation was also seen in the study of mice administrated exfoliatin toxin of Staphylococcus which evoked human staphylococcal scalded skin syndrome.

• Carbon letters
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• v.8 no.4
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• pp.274-279
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• 2007

In order to understand the breakthrough behaviour of iodine vapours on impregnated carbon systems, an active carbon, 80 CTC grade, $12{\times}30$ BSS particle size and $1104\;m^2/g$ surface area, was impregnated with metal salts such Cu, Cr, Ag, Mo and Zn, and an organic compound Triethylene diamine (TEDA) to prepare different carbon systems such as whetlerite, whetlerite/TEDA, whetlerite/KI/KOH and ASZMT. The prepared adsorbents along with active carbon were characterized for surface area and pore volume by $N_2$ adsorption at liquid nitrogen temperature. These carbon systems were compared for their CT (concentration X time) values at 12.73 to 53.05 cm/sec space velocities and 2 to 5 cm carbon column bed heights. The carbon column of 5.0 cm bed height and 1.0 cm diameter was found to be providing protection against iodine vapours up to 5.5 h at 3.712 mg/L iodine vapour concentration and 12.73 cm/sec space velocity. The study clearly indicated the adsorption capacities of carbon systems to be directly proportional to their surface area values. Dead layer with all the prepared carbon systems was found to be less than 2.0 cm indicating it to be minimum bed height to have protection against $I_2$ vapours. Effect of carbon bed height and flow rate was also studied. The active carbon showed maximum protection at all bed heights and flow rates in comparison to all other impregnated carbon systems, showing that only physical adsorption is responsible for the removal of iodine vapours.

• Journal of Environmental Health Sciences
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• v.36 no.4
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• pp.337-341
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• 2010

The modified simultaneous differential staining technique, which enables double staining of cartilage and bones, needs to be improved to prevent soft tissues from being damaged during the staining process. Key factors influencing the extent to which soft tissues are damaged include the fixative used, macerating time, potassium hydroxide concentration, incubation temperature and the removal of skin from specimens. Here we describe a protocol that enables the hardening of tissues during bleaching and maceration. We also describe a method for objectively measuring rates of cartilage and bone growth. The use of formalin as a fixative rendered soft tissues more rigid due to the resulting chemical bonds formed between proteins. Blotted specimens were immersed in 1% potassium hydroxide (KOH) and incubated at $37^{\circ}C$ for 1 day (smaller specimens) or 2-3 days (larger specimens). The 1% KOH solution was also used as the diluent solution for the subsequent immersion in a graded series of 30%, 50%, 70%, 90%, 100% glycerol solutions, a procedure that made soft tissues even more transparent and hardened. It was not necessary to remove the skin of specimens shorter than 2 cm, since the macerating solution could easily penetrate their thin skin layer and continuously remove those pigments hindering visibility. Since excessive osmosis is another factor that can damage soft tissues in the macerating process by causing the rupture of those cells not able to withstand the osmotic pressure, here it was minimized by balancing the salt concentration between the interior and exterior of cells with the addition of 0.9% sodium chloride (NaCl) in the macerating solution. Finally, to determine the proportions of cartilage and bone growth, photographs of the stained specimens were taken with a dissecting microscope and sections corresponding to the cartilage and bones were cut out from the printed pictures and weighed. Our results show that this method is suitable for the objective evaluation of bone and cartilage growth.

• KSBB Journal
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• v.15 no.2
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• pp.150-155
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• 2000

Antioxidative activity of c비ture of Streptomyces sp. BH-405 was investigated. After removal of pellets of Streptomyces sp. B BH-405, antioxidative substances were is미ated and suc$\infty$sively purified from culture of Streptomyces sp. BH-405 by by thin | layer chromatography $\pi$LC) or silica gel column chromatography. The fraction 3 obtained from ethylether fractionation of the C culture appeared highest level of anti oxidative activity as determined by thiocyanate method. Band 2 obtained by further P purification of this fraction showed higher anti oxidation level than that of same concentration of dl- $\alpha$ -tocopherol, butylated h hydroxy anisole (BHA). The band 2 showed higher rate of 1, 1.diphenyl 2-picrylhydrazyl (DPPH) decolorization than dl-$\alpha$-tocopherol. In the rat liver microsomes, band 2 rapidly inhibited lipid peroxidation which was initiated enzymatically by r reduced nicotinamide adenine dinucleotide phosphate (NADPH) or non-enzymatically by Fenton’s reagent. Band 2 inhibited on | lipid peroxidation of mitochondria or the linoleic acid hydro peroxide induced peroxidation system. It is concluded that band 2 obtained by fractionation of Streptomyces sp. BH-405 cultivation contained antioxidants with the capacity to inhibit oxidative m modification.