• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.1
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• pp.67-75
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• 2005

The size and main ingredient of hot particulate generated during the nuclide experiment in hot cells of nuclear facilities were 0.5300 $\mu$m and UO$\_2$. A cyclone filter equipment which consists of a cyclone and Bag/HEPA filter was devised to remove hot particulate generated during the nuclide experiment in hot cells of nuclear facilities. The experimental conditions to maximize the collection efficiency of hot particulate were suggested through experiments done with the cyclone filter equipment. With the large size of simulated particulate, the collection efficiency of the particulate was high. When the size of simulated particulate was more than 5 $\mu$m, the collection efficiency of the particulate was more than $80\%$ and when the size of simulated particulate was less than 1.0 urn, the collection efficiency decreased by less than $70\%$. If the inflow velocity of simulated particulate was increased, the collection efficiency of the particulate was also increased. When the inflow velocity of simulated particulate was more than 12m/sec, the collection efficiency was higher than $70\%$, but after 17 m/sec inflow velocity, no change observed. The collection efficiency of the simulated particulate can be enhanced with the length of vortex finder inside the chamber. With the length of vortex finder, 7.2cm, the observed collection efficiency of the particulate was the maximum. Moreover, when the sub-cone was attached under the cyclone, the collection efficiency of cyclone increased $2\%$. It was found that effect by attachment of sub-cone was not serious.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.207-212
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• 2012

In this work, a 70/140 GHz dual-band push-push voltage controlled oscillator(VCO) has been developed based on a 0.18-${\mu}m$ SiGe BiCMOS technology. The lower band and the upper band oscillation frequency varied from 67.9 GHz to 76.9 GHz and from 134.3 GHz to 154.5 GHz, respectively, with tuning voltage swept from 0.2 to 2 V. The calibrated maximum output power for each band was -0.55 dBm and -15.45 dBm. The VCO draws DC current of 18 mA from 4 V supply.

• Journal of the Korean Geotechnical Society
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• v.33 no.1
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• pp.5-15
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• 2017

Skin friction may be one of the most critical factors in designing the prebored and precast pile. Special attention was given to the interface behavior of cement milk-surrounding soil during the installation of prebored and precast pile. Small-scale field model pile test was conducted for the case of single pile. The size and geometry of the small-scale field model piles were designed with pile length 1.3m, boring diameter 0.067 m. Quick maintain-load test was conducted for the cases of boring diameter 150, 125, 90, 86, 74 mm and water-cement ratio 90, 70, 60%. It was shown that the bearing capacity of the pile increased as the cement-water ratio and cement milk thickness increased. Considering the scale effect between the small-scale model test and the actual construction site, it was found that cement milk thickness of 0.1~0.4D (50~200 mm) was reasonable for the stability of the structure. Also, the proper cement paste water / cement ratio was about 70% when considering the results of this study and quality control.

• Journal of the Korean Chemical Society
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• v.41 no.5
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• pp.246-250
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• 1997

In the presence of optimum amounts of hydroxylamine, trace ruthenium(III) can be conveniently determined in acidic (boric) media by coupling catalytic hydrogen processes with adsorptive accumulation of the catalyst, using differential pulse voltammetry. Cyclic voltammetry was used to characterize the redox and interfacial processes. Optimal experimental conditions were found to be a stirred borate (0.015 M, pH 2.5) solution containing 0.55 M hydroxylamine, a preconcentration potential of - 0.70 V, and a scan rate of 5 mV/s. With a 7 min accumulation period the detection limit was 3${\times}$10-10 M. The possible interferences by other platinum group metals are investigated.

• Journal of Magnetics
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• v.17 no.2
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• pp.86-95
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• 2012

This study investigated the effects of adding a third alloying element, Ni, to create $Fe_{70-x}Pd_{30}Ni_x$ (x = 2, 4, 6, 8 at.% Ni) ferromagnetic shape memory alloys (FSMAs). The Ni replaced a portion of the Fe. The $Fe_{70-x}Pd_{30}Ni_x$ alloys were homogenized through hot and cold forging to gain a ~38% reduction in thickness, next they were solution-treated (ST) with annealing recrystallization at $1100^{\circ}C$ for 8 h and quenched in ice brine, and then aged at $500^{\circ}C$ for 100 h. Investigation of the microstructures and magnetostriction indicated that the greater Ni amount in the $Fe_{70-x}Pd_{30}Ni_x$ alloys reduced saturation magnetostriction at room temperature (RT). It was also observed that it was more difficult to generate annealed recrystallization. However, with greater Ni addition into the $Fe_{70-x}Pd_{30}Ni_x$ (x = 6, 8 at.% Ni) alloys, the $L1_0+L1_m$ twin phase decomposition into stoichiometric $L1_0+L1_m+{\alpha}_{bct}$ structures was suppressed after the $500^{\circ}C$/100 h aging treatment. The result was that the $Fe_{70-x}Pd_{30}Ni_x$ (x = 6, 8 at.% Ni) alloys maintained a high magnetostriction and magnetostrictive susceptibility (${\Delta}{\lambda}{_\parallel}{^s}/{\Delta}H$) after the alloys were aged at $500^{\circ}C$ for 100 h. This magnetic property of the $Fe_{70-x}Pd_{30}Ni_x$ (x = 6, 8 at.% Ni) alloys make it suitable for application in a high temperature (T > $500^{\circ}C$) and high frequency environments.

• The Korea Journal of Herbology
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• v.31 no.6
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• pp.45-52
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• 2016

Objectives : This study was performed to investigate the antioxidant activity of water and ethanol extracts from Sasa borealis leaves, stems and roots. Methods : Sasa borealis leaves, stems and roots extract were prepared using water and ethanol. The total polyphenol and total flavonoid contents were analyzed. 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging activity, SOD like activity, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)(ABTS), hydroxyl radical scavenging activity, and Nitrite scavenging activity assays were carried out to determine the antioxidant activities. Results : The antioxidant activities of the Sasa borealis appeared higher in ethanol extract than water extracts. Total polyphenol and total flavonoids contents in ethanol extracts of leaves were $24.6mg/m{\ell}$ and $14.3mg/m{\ell}$, respectively, which were much higher than those of any other parts. SOD like activity was 70% ethanol extract of the leaves was highest with 15.68%. Electron donating ability was 70% ethanol extract of the leaves had the highest 59.07%. It exhibited high electron donating ability than BHT(45.68%). Nitrite scavenging activity of 70% ethanol extract was higher than the water extract at pH 2.5 and pH 4.2. Nitrite scavenging activity was 70% ethanol extract of the leaves was the highest 75.2%. Hydroxyl radical scavenging activity was 70% ethanol extract of the leaves was highest with 16.16%, showed very low activity than BHT(61.56%). Conclusions : These results suggest that 70% ethanol extracts from Sasa borealis leaves, exhibited higher antioxidant activities than those of root and stem, and can be potentially used as proper natural antioxidants.

• Korean Journal of Medicinal Crop Science
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• v.22 no.3
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• pp.217-222
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• 2014

This study was to investigate anti-skin wrinkle effect of aronia extracts by extraction processes. The 70% ethanol extract by ultrasonification process (UEE) showed highest DPPH scavenging activity of 90.4% in order water extract (WE), 70% ethanol extract (EE) was measured 84.2%, 84.3%. collagen production measured $245ng/m{\ell}$ from UEE. WE was measured $53.5ng/m{\ell}$ and EE was measured $224.4ng/m{\ell}$. MMP-1 production was observed lowest $22.5pg/m{\ell}$ at UEE. MMP-1 production of EE was $34.6pg/m{\ell}$ and WE was $102.3pg/m{\ell}$. These results were found the highest antioxidant and anti-wrinkle effect at UEE among three processes. It was also confirmed that anti-skin wrinkle activities of the aronia extract was strongly correlated with anti-oxidant activities due to high amounts of antocyanins in the extract.

• Journal of the Korean Solar Energy Society
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• v.29 no.3
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• pp.45-50
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• 2009

To estimate the operating performances of the geothermal heat exchange pipe(GHEX), GHEXs of 400RT geothermal system were measured and analyzed through a year. The followings are the results. The temperature of 2 GHEXs installed 4m apart was fluctuated very similarly. When the geothermal system is nor operating or is operating as heating mode, the temperature of G.L.-170m was always higher than G.L.-70m's. But it reversed when the geothermal system is operating as cooling mode. And through a year, it has been observed that the temperature of G.L.-170m is increased approximately $1.5^{\circ}C$. With previously mentioned results, the heat transfer capacity of G.L.-70m's geological stratum is estimated as higher than that of the G.L.-170m.

• Animal Systematics, Evolution and Diversity
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• v.25 no.3
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• pp.301-308
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• 2009

Three Loxodes ciliates collected from estuarine littoral, wetland and small pond in Korea, were identified as Loxodes kahli Dragesco and Njin$acute{e}$, 1971, L. magnus Stokes, 1887 and L. vorax Stokes, 1885. The descriptions for these species based on living and protargol impregnated specimens were given. Morphometry, illustrations and microphotographs were also provided. Diagnoses of three species are as follows. Loxodes kahli; size in vivo $160-300{\times}40-70\;{\mu}m$; oral area with reddish to brownish pigments; 6-11 macronuclei arranged linearly; 5-9 micronuclei located near macronuclei; 4-12 M$\ddot{u}$ller's vesicles; somatic kineties on right 18-20 and left 2 in number. L. magnus: size in vivo $250-470{\times}87-15\;{\mu}m$; body colored dark brown; 5-13 macronuclei; 8-13 micronuclei; 8-18 M$\ddot{u}$ller's vesicles; somatic kineties on right 23-26 and left 2 in number. L. vorax: size in vivo $70-160{\times}20-35\;{\mu}m$; oral area with brownish pigments; 2 macronuclei; 1 micronucleus located between macronuclei; 2-4 M$\ddot{u}$ller's vesicles; somatic kineties on right 18-20 and left 2 in number.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.210-219
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• 2017

This study aimed to establish an optimal extraction process and high-performance liquid chromatography (HPLC)-photodiode array (PDA) analytical method for determination of marker compounds, dihydrokaempferol (DHK) and 3-O-methylquercetin (3-MeQ), as a part of materials standardization for the development of health functional foods from stems of Opuntia ficus-indica var. saboten (OFS). The quantitative determination method of marker compounds was optimized by HPLC analysis, and the correlation coefficient for the calibration curve showed very good linearity. The HPLC-PDA method was applied successfully to quantification of marker compounds in OFS after validation of the method in terms of linearity, accuracy, and precision. Ethanolic extracts from stems of O. ficus-indica var. saboten (OFSEs) were evaluated by reflux extraction at 70 and $80^{\circ}C$ with 50, 70, and 80% ethanol for 3, 4, 5, and 6 h. Among OFSEs, OFS70E at $80^{\circ}C$ showed the highest contents of DHK and 3-MeQ of $26.42{\pm}0.65$ and $3.88{\pm}0.29mg/OFS100g$, respectively. Furthermore, OFSEs were determined for their antioxidant activities by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and lipid peroxidation (LPO) inhibitory activities in rat liver homogenate. OFS70E at $70^{\circ}C$ showed the most potent antioxidant activities with $IC_{50}$ values of $1.19{\pm}0.11$ and $0.89{\pm}0.09mg/mL$ in the DPPH radical scavenging and LPO inhibitory assays, respectively. To identify active components of OFS, various chromatographic separation of OFS70E led to isolation of 11 flavonoids: dihydrokaempferol, dihydroquercetin, 3-O-methylquercetin, quercetin, isorhamnetin 3-O-glucoside, isorhamnetin 3-O-galactoside, narcissin, kaempferol 7-O-glucoside, quercetin 3-O-galactoside, isorhamnetin, and kaempferol 3-O-rutinoside. The results suggest that standardization of DHK in OFSEs using HPLC-PDA analysis would be an acceptable method for the development of health functional foods.