• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.554-563
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• 1999

For the purpose of elucidating the polymerization modes of dual-cure restorative materials and comparing them with single-cure restorative materials, a study was performed on the light-cured composite resin, dual-cure composite resin, dual-cure glass ionomer cement and chemical-cure glass ionomer cement. By measuring the microhardness of each material at 0mm, 1mm and 3mm depth during initial 24 hours with predetermined interval, the state of polymerization and degree of conversion was indirectly evaluated for each material, and obtained results are as follows : 1. All of four materials tested showed significant increase in microhardness after 24hrs compared with just after curing starts. 2. In all materials except Ketac-fil, there showed a significant difference in microhardness between each depth at each time interval. 3. In the test of lap time till final curing for each material, the polymerization process was revealed to last longer in the dual-cure type materials than in single-cure type materials at 3mm depth. Based on the results above, it was demonstrated with materials of dual-cure mode that the degree of conversion increases by successive curing reactions even in the deeper layers where sufficient curing light is impermeable.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.660-664
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• 2003

The exposure dose form recycling on a large amount of the steel scrap from the KRR-1&2 decommissioning activities was evaluated, and also the clearance level was derived. The maximum individual dose and collective dose were evaluated by modifying internal dose conversion factor which was based on the concept of effective dose in ICRP 60, applied to the RESRAD-RECYCLE ver 3.06 computing code, IAEA Safety Series III-P-1.1 and NUREG-1640 as the assessment tool. The result of assessment for individual dose and collective dose is 23.9 ${\mu}Sv$ per year and 0.11 man$\cdot$Sv per year respectively. The clearance levels were ultimately determined by extracting the most conservative value form the results of the generic assessment and specific assessment methodologies. The result of clearance level for radionuclides($Co^60$, $Cs^137$) is less than $1.67{\times}10^{-1}$ Bq/g to comply with the clearance criterion(maximum individual dose : 10 $\muSv$ per year, collective dose : 1 man$\cdot$Sv per year) provided for Korea Atomic Energy Act and relevant regulations.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.385-390
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• 2015

Purpose: This study evaluated the static stereoacuity by Distance Randot Stereotest (STEREO OPTICAL. Co., Inc. USA) and the dynamic stereoacuity by three-rods test (iNT, Korea). Criterion and correlation of stereoacuity between both tests and usefulness of two stereotest methods were also evaluated. Methods: For normal adults of 109 (male 61, female 48), mean age of 20.88 (19-32 years) years old, static stereoacuity by using Distance Randot Stereotest at 3 m distance, dynamic stereoacuity by using three-rods test at 2.5 m distance were measured. Results: The mean of distance static stereoacuity was $155.77{\pm}133.11sec$ of arc and the mean of error distance dynamic stereoacuity $11.13{\pm}9.69mm$. With equivalent-conversion stereoacuity of $23.44{\pm}20.96sec$ of arc, there was statistically significant differences (p=0.00) between two dynamic stereoacuity, but correlation was relatively low (${\rho}=0.226$). In the case of dynamic stereoacuity, separated to normal range by criterion of the error distance 20 mm, it showed the error distance of less than 20 mm in 97 subjects(89%) whose average of error distance and conversion mean dynamic stereoacuity were $8.43{\pm}5.10mm$ and $17.68{\pm}10.67sec$ of arc. repectively. The error distance of was equivalent-conversion dynamic stereoacuity 40.99 sec of arc (PD 62 mm basis) was 20 mm. Conclusions: The results of lower correlation between static and dynamic stereoacuity suggest that seterotest should be applied separately to different functions. The results of this study also suggest that Distance Randot Stereotest can be applied to static stereoacuity excluding monocular cues. Three-rods test can be applied to dynamic stereoacuity containing the response of the eye-hand coordination in the daily life of natural vision condition, including the monocular cues. These different approaches canprovide a criterion of the two stereoacuity and parallel use of the two tests would be useful. For dynamic stereoacuity by three-rods test, error distance 20 mm in a normal range of adults can be used as a criteria to get statistical meaning of the results.

• Current Photovoltaic Research
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• v.7 no.4
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• pp.103-110
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• 2019

Cu(In,Ga)₃Se₅ (β-CIGS) has a band gap of 1.35 eV, which is an optimum value for high solar-energy conversion efficiency. The effects of Cu and Ga content on the cell performance were investigated previously. However, the effect of Se content on the cell performance is not well understood yet. In this work, β-CIGS films were fabricated by three-stage co-evaporation of elemental sources with various Se fluxes at the third stage instead of at all stages. The average composition of five samples was Cu_1.05(In_0.59,Ga_0.41)3Se_y, where the stoichiometric y value is 5.03 and the stoichiometric Se/metal (Se/M) ratio is 1.24. We varied the Se/metal ratio in a range from 1.18 to 1.28. We found that the best efficiency was achieved when the Se/M ratio was 1.24, which is exactly the stoichiometric value where the CIGS grains on the CIGS surface were tightly connected and faceted. With the optimum Se/M ratio, we were able to enhance the cell efficiency of a β-CIGS solar cell from 9.6% to 12.0% by employing a Na₂S post deposition treatment. Our results indicate that Na₂S post deposition treatment is very effective to enhance the cell efficiency to a level on par with that in α-CIGS cell.

• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.275-286
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• 1994

Plasma protein which has been known as one of nonspecific immunostimulators was added to feedstuff to examine its effect on the enhancement of cellular immune response in porcine immune system. A total of 40 piglets, 20 male and 20 female each, were fed for 30 days with or without plasma protein. The peripheral blood were collected and analyzed for the investigation of leukocyte subpopulations and their activities by using a panel of monoclonal antibodies specific to porcine leukocyte differentiation antigens and flow cytometry. The results obtained as follows. 1. Total weight gain, daily feed intake and feed conversion rate for 10 days were significantly improved to 56%, 20% and 22% in the piglets fed plasma protein, respectively. 2. A significant increase in N (null or non T/non B) cells was also noticed. Leukocyte proportion from piglets fed plasma protein was 20.2-24.7%, otherwise that from piglets fed without plasma protein was 12.3-13.4%, respectively. 3. A significant increase in the proportion of B cells and cells expressing poCD1 was not found in piglets fed plasma protein. 4. Reaction with monoclonal antibodies specific to adhesion molecules, poCD11a, poCD11b, poCD44 and poCD45A and poCD45B, has shown that leukocyte subpopulation from piglets fed plasma protein did not significantly higher than that from piglets fed without plasma protein. 5. Total proportion of granulocytes and monocytes was about 50% in both group and the proportion after treated with Hypaque/Ficoll was 2.7% and 5.8% in each group, respectively.

• Journal of Environmental Health Sciences
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• v.37 no.4
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• pp.315-322
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• 2011

Objectives: Organic matter and nitrogen were removed using the EGSB process, a high-rate anaerobic process, in combination with a nitritation-denitritation process, in order to ensure the stable treatment of seafood processing wastewater. Methods: The upflow velocity of an EGGS reactor was operated at 10 m/hr for maximal organics removal efficiency. For removal of nitrogen from seafood processing wastewater a nitritation-denitriation process was applied Results: The efficiency of the EGSB process showed that it has an 80% or more organic matter (CODcr) removal efficiency with an HRT of six hours or more at influent loadings of 17.34 kgCOD/$m^3$/day or less. The methane product for TCODcr removal was 0.23-0.38 $m^3CH_4$/kgCODrem., which was similar to the theoretical generation of STP-state methane, 0.35 $m^3CH_4$/kgTCODrem. In the nitritation-denitritation process, the nitritation conversion rate to $NH_4^+$-N concentration was 82% to 87%, 72% to 81% and 64% to 69% when HRT was 24 hr, 21 hr and 18 hr, respectively. In the denitritation process, the ratio of SCOD consumption to NOx-N removal ranged from 2.347 to 2.587. It was 2.472 on average. Conclusions: The optimal HRT for stable processing of seafood processing wastewater is six hours or more. The ratio of nitrite to total NOx-N was 82% to 96%, which indicates that nitrite accounts for the largest portion of the product.

• Progress in Superconductivity
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• v.8 no.1
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• pp.59-64
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• 2006

High $J_c\;YBa_2Cu_3O_x$ superconducting films were fabricated by MOD method using fluorine-free dichloroacetic acid(DCA) as chelating solvent for preparing precursor solution. Coating solutions were prepared by dissolving Y-, Ba- and Cu-acetates in DCA solvent followed by drying in rota vapor to obtain the blue gel that is diluted in methanol and 2-methoxyethanol for adjusting the cation concentration. DCA-MOD precursor solution was coated on a single crystal(001) $LaAlO_3(LAO)$ substrate by a dip coating method with a speed of 25 mm/min. Coated films were calcined at lower temperature up to $500^{\circ}C$ in flowing oxygen atmosphere with a 7.2% humidity. Conversion heat treatment was performed at various temperatures of $780{\sim}810^{\circ}C$ for 2 h in flowing Ar gas containing 1000 ppm oxygen with a humidity of 9.45%. SEM observations showed that films have very dense microstructures for the films prepared at the temperature higher than $800^{\circ}C$ regardless of diluting solvent; methanol or 2-methoxyethanol. X-ray diffraction analysis showed that YBCO grains grew with a (001) preferred orientation. A High critical current density($J_c$) of 1.28 $MA/cm^2$(@77 K and self-field) was obtained id. the YBCO film prepared using 2-methoxyethanol as a solvent.

• Journal of Powder Materials
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• v.8 no.3
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• pp.163-167
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• 2001

A bulk porous $CaZrO_3/MgO$ composite with plantinum nano-dispersion was synthesized in air atmosphere through the combination of several in situ reactions, including the pyrolysis of $PtO_2$. A mixture of $CaMg(CO_3)_2$(dolomite), $ZrO_2$, $PtO_2$ and LiF (0.5 wt%, as an additive) was cold isostatically pressed at 200 MPa and sintered at $1100^{\circ}C$ for 2 h. The porous $CaZrO_3/MgO/Pt$ composite ($CaZrO_3/MgO$ : Pt=99 : 1 in volume) had a uniformly open-porous structure (porosity: 56%) with three-dimensional (3-D) network and a narrow pore-size distribution, similarly to the porous $CaZrO_3/MgO$ composites reported before. Catalytic Properties (viz., NO direct decomposition and NO reduction by $C_2H_4$) of the $CaZrO_3/MgO/Pt$ composite were investigated up to $900^{\circ}C$. In the absence of oxygen, the NO conversion rate reached ~52% for the direct decomposition and ~100% for the reduction by $C_2H_4$, respectively. The results suggest the possibility of the porous composite as a multifunctional filter, i.e., simultaneous hot gas-filtering and $de-NO_x$ in one component.

• Korean Journal of Pharmacognosy
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• v.26 no.4
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• pp.355-359
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• 1995

To find serotonin(5-hydroxytryptamine, 5-HT)-antagonizing activities in traditional herbal drugs, crude extracts from 66 kinds of traditional herbal drugs were randomly screened for inhibitory effects on 5-hydroxytryptophan(HTP)-induced diarrhea in mice. Intraperitoneal injection of 5-HTP(2.5 mg/kg) induced diarrhea in 92% of mice, when observed from 10 to 15 min after injection. Crude extracts(2 g/kg) from 66 kinds of traditional herbal drugs were orally pretreated for 1 h before 5-HTP injection. Of the 66 herbal drugs screened, Ephedrae Herba(麻黃), Cimicifugae Rhizoma(升麻), Anisi stellati Fructus(八角茴香), Aurantii Fructus(枳實), Polygalae Radix(遠志) showed the most potent inhibiting activities against 5-HTP(2.5 mg/kg)-induced diarrhea in mice. There are at least 3 possible mechanisms that would be responsible for the inhibitory effect of crude extracts on 5-HTP-induced diarrhea; 1) crude extract-induced inhibition of the activity of aromatic aminoacid decarboxylase catalyzing the conversion of 5-HTP to 5-HT, 2) crude extract-induced blockade of 5-HT receptor(s) in the gastrointestinal tract responsible for 5-HTP-induced diarrhea, 3) crude extract-induced inhibition of gastrointestinal activity, irrespective of 5-HT system. The exact mechanisms and molecules, responsible for the inhibitory effect of crude extracts on 5-HTP-induced diarrhea remain to be clarified.

• Journal of the Korea Organic Resources Recycling Association
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• v.6 no.1
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• pp.21-30
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• 1998

The effects of compost inoculation on the degradation of cellulosic fraction in composting of food waste and paper mixture were investigated by bench-scale composting. With the increase of seed inoculation, the time to reach the peaks of temperature, $CO_2$ evolution rate, and ammonia evolution rate was reduced, indicating that seed compost had beneficial effects on the enhanced degradation of organic materials at the early stage of composting. However, the final conversion of organic matters and the loss of ammonia were not affected by the amount of seed compost inoculated. The increasing of seed inoculum also resulted in the higher level of cellulase activity at initial stages and rapid rise to the maximums, suggesting that initial supply of sufficient cellulolytic microorganisms might facilitate the evolution of cellulase activity. The cellulose was degraded substantially during the increasing phase of cellulase activity, while they showed similar values at the end of 20 days composting. As a result, the seed inoculation seemed to be effective to the enhanced evolution of cellulase activity and cellulose degradation at initial stage of composting. But it did not contribute to increase the final degradation of cellulose after the entire composting reaction of 20 days.