• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.797-810
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• 1998

The purpose of this study was to develop a new way of delivery system of chlorhexidine using self-curing acrylic resin. Different preparations of chlorhexidine, such as chlorhexidine varnish($Chlorzoin^{(R)}$) and chlorhexidine diacetate crystalline, were mixed into self-curing acrylic resin with different methods. Every resin plate was made and was immersed in 100ml of distilled water individually, and kept in an incubator at $37^{\circ}C$. Solution(0.8ml) was collected from the each container at every 24 hours, and the amount of released chlorhexidine in the solution was measured in an ultraviolet spectrophotometer at 255nm. Flexural strength of all of the resin plates in the Experiment 2-A and 2-B were measured using Instron at the end of the experimental periods. The results were as follows: 1. It was found that chlorhexidine was released from the experimental groups in the Experiment 1, 2-A, and 2-B. And the release of chlorhexidine from all of the experimental groups showed a pattern of sustained-release preparation. 2. It seemed likely that a condition of "dryness" reduced a release of chlorhexidine from the chlorhexidine varnish. 3. It may be stated that a method of "chlorhexidine diacetate mix" with the polymer be more efficient than a method of "Chlorzoin mix" with the monomer. 4. Although it was evident that a flexural strength of the acrylic resin plates be reduced by a mix of either Chlorzoin or chlorhexidine diacetate crystalline, it seemed likely that the resin plates except Group 4 and 5 in the Experiment 2-B may be usable in the clinical situation.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.471-478
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• 2012

The objective of the study is to find a way to utilize MSWI slag as filter material and to verify it. To do so, stability as filter material was tested, and used Ju-Munjin filter sand as control group to run actual filtering experiment to analyze filtering efficiency. According to result, MSWI slag is usable within designated waste acceptable standards. Also, it showed similar level of filtering capability to filter sand. Thus, MSWI slag could help to save and recycle resources if used as filtering material instead of filter sand As result of filtering test, SS and COD showed about same level of filtering capability similar to standard filter sand. MSWI slag has shown 26.96% higher with T-N, and 6.55% higher with T-P compared to standard filter sand. Also, remove efficiency comparison result with No. 40#(0.43mm) and mixed diameter showed equal or greater filtering capability.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.124-131
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• 2010

Rock Bolt generally utilizes deformed reinforcing bar welded from structural steel of which strength is higher than required for making advantageous use of the support function of ground. In the condition with highly corrosive underground water, however, problem frequently occurs on tunnel and slope stabilization in terms of repair, rehabilitation and maintenance issues due to the destruction of Rock Bolt by corrosion of steel. A structural performance evaluation for GFRP Rock Bolt was conducted for the purpose of resolving the foregoing problem and at the same time developing a permanently-usable support material. This study intended to evaluate the safety factor of GFRP Rock Bolt by implementing the slope stability interpretation via structural analysis on the basis of its structural characteristics derived from both tensile force function test and shear force function test. It is judged based on the results that GFRP Rock Bolt would secure sufficient ground stability as an alternative material for existing Steel Rock Bolt.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.2
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• pp.19-28
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• 2018

In this paper, we studied on the sampling of ocean meteorological data to analyze signature of naval ships. The newest ocean meteorological data, that was quality controled by the Korea Meteorological Administration(KMA), was collected. Outliers were removed from the data by setting the usable range of data. After that, the data size was reduced through the random sampling method, taking geopolitical significance and effective area of buoy, for probabilistic analysis. Moreover, the sample sizes were set at 100, 200, and 400 by considering the population size and a 95% confidence level. The final sample was obtained using the two-dimensional stratified sampling method based on highly correlated water temperature and air temperature. The sum of the squared errors and the confidence interval was calculated to compare the result of sampling. As a result, this study proposed reasonable sample size for infra­red signature analysis of naval ships.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.434-439
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• 1995

Chinese radish juice(CRJ) was used as a culture medium for the production of Candida utilis ATCC 42416 biomass. Soluble solid and total sugar contents of Chinese radishes were in the range between 5.5 and $8.8^{\circ}$Brix and 3.5 and 6.5%, respectively. Since sugar in radishes are in readily usable forms, pretreatm ent procedures were not necessary after the extraction of juice from fresh radishes. In shake flask experimetns, C. utilis ATCC 42416 grew well in CRJ and completed growth in 24 hrs at $30^{\circ}C$ and 200 rpm. Maximum cell dry weight obtainable from a liter of CRJ(1.0% sugar $DCRJ{\times}5$) was 21.5g, when the yeast was grown on CRJ diluted 5 times or more with tap water to make sugar content to be eual to or less than 1.0%. Supplementation of 5-fold diluted CRJ with some nutrients did not greatly influence the growth rate, yeast biomass production, or cell protein content significantly, indicating that CRJ itself was a good substrate for the production of biomass by C. utilis ATCC 42416.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.2
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• pp.173-183
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• 2010

In a split beam echo sounder, the transducer design needs to have minimal side lobes because the angular position and level of the side lobes establishes the usable signal level and phase angle limits for determining target strength. In order to suppress effectively the generation of unwanted side lobes in the directivity pattern of split beam transducer, the spacing and size of the transducer elements need to be controlled less than half of a wavelength. With this purpose, a 50 kHz tonpilz type transducer with a half-wavelength diameter in relation to the development of a split beam transducer was designed using the equivalent circuit model, and the underwater performance characteristics were measured and analyzed. From the in-air and in-water impedance responses, the measured value of the electro-acoustic conversion efficiency for the designed transducer was 51.6%. A maximum transmitting voltage response (TVR) value of 172.25dB re $1{\mu}Pa/V$ at 1m was achieved at 52.92kHz with a specially designed matching network and the quality factor was 10.3 with the transmitting bandwidth of 5.14kHz. A maximum receiving sensitivity (SRT) of -183.57dB re $1V/{\mu}Pa$ was measured at 51.45kHz and the receiving bandwidth at -3dB was 1.71kHz. These results suggest that the designed tonpilz type transducer can be effectively used in the development of a split beam transducer for a 50kHz fish sizing echo sounder.

• Journal of Animal Environmental Science
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• v.16 no.1
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• pp.21-28
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• 2010

The odor problem in the livestock is increasing by 7% annually. Most importantly, the livestock odor problem in swinery accounts for the maximum ratio (54%). In this study, we reviewed the possibility of deodorizing swinery using an odor reduction device that can be used with the water washing system. First, the study confirmed that the solubility of odor gas, which was hydrogen sulfide, was very low regardless of the contact time with solvent, but the solubility of methyl mercaptan was found to increase along with the increase in time. The solubility of other odor gases, such as dimethyl sulfide, dimethyl disulfide and ammonia, was considerably high. Consequently, it is considered that if the odor reduction device for the water washing system deodorization is used in a swinery, the time during which the exhaust gas is in contact with usable water must be extended, or solvent quantity must be expanded. However, it is predicted that although hydrogen sulfide is easily generated in the anaerobic condition, it is difficult to expect high odor reduction efficiency because this gas has low solubility in water, especially in case it is used in the deodorization of the water washing system. The result of the solubility experiment using the bench-scale device practically manufactured represented the higher odor reduction ratio than expected. This result was possible because the removal efficiency of dust particles could be reached up to 93%. Therefore, it is judged that also the odor gas absorbed on dust particles could be removed by removal of dust. Consequently, it is expected that the higher order reduction ratio will be possible by structural improvement for increasing contact with water and odor gas.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.345-355
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• 2017

This study was conducted to evaluate rice seed disinfection efficacy of loess-sulfur for the suppression of Bakanae disease caused by Fusarium fujikuroi. Rice seeds were treated at different concentrations of loess-sulfur, soaking time and temperature, and combination of hot-water treatment. Rice cultivar, Shindongjin harvested from Bakanae disease-infested area in 2015, was used. Loess-sulfur was treated as follows; concentration of undiluted solution, 2%, 1% and 0.5%; soaking time of 24 and 48 hours; treatment temperature of $20^{\circ}C$ and $30^{\circ}C$; hot water treatment or not. Optimal conditions of rice seed disinfection were selected soaking time of 48 hours and the suspension of 0.5% and 1% loess-sulfur by investigating seed germination and isolation frequency of Fusarium spp. on Komada agar medium in vitro, and were established 3 disinfection conditions as hot water ($60^{\circ}C$, 10 min.) + 1% loess-sulfur ($20^{\circ}C$, 48 hours), 1% loess-sulfur only ($30^{\circ}C$, 48 hours) and 1% loess-sulfur only ($20^{\circ}C$, 48 hours) through additional test in greenhouse. Above 3 conditions were verified by rice seedling box and paddy field test in the way of investigating Bakanae diseased plants (%) and healthy plants (%). Consequently, most effective rice seed disinfection conditions on Bakanae disease were combination of hot water and 1% loess-sulfur and loess-sulfur only at $30^{\circ}C$. Furthermore, treatments with these conditions showed control value of 100% were maintained from seedling to the heading stage in the field. However, treatment of 1% loess-sulfur only at $20^{\circ}C$ showed low control value of 78.2% in paddy field. Hot water only treatment turned out to be an effective disinfection method when conducted thoroughly with $60^{\circ}C$, 10 min. However, it was thought additional soaking process with loess-sulfur after hot water treatment served more high control effect against Bakanae disease when rice seeds were disinfected on a large scale. This results expected rice seed disinfection with loess-sulfur were effectively and easily usable method if farmers had only one of either hot water-disinfector or seed-disinfector. In addition, loess-sulfur is well-known to farmers, simple to manufacture method and cheap.

• Journal of Korea Water Resources Association
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• v.45 no.3
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• pp.317-329
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• 2012

It is increasing to make an efforts on preventing natural river environment and preserving natural river ecosystem as development is unavoidable. In the case of inconsistent river flow caused by reservoir development, fishway is an alternative to secure fish diversity and preserve existing river ecosystem but existing fishway was established without full study for their functions. In this study, hydraulic characteristics of natural fishway established on Beakje weir's right side were analyzed. The results show that the fishway has reasonable depth and velocity condition which inhabit condition is enough for a dominant species. For assessing the optimal design of fishway, the Weighted Usable Area (WUA) was calculated by using two dimensional numerical model under the ordinary flow condition. The comparison results for various pool widths in the fishway show that the designed width has maximum WUA for adult Zacco platypus but WUA is maximized with 1m wider pool width than designed width for spawning.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.163-165
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• 1985

In assay of antifungal activity of fatty acids which slightly soluble in water against phytopathogenic fungi in vitro, it is necessary that evenly disperse fatty acid to assay in culture medium for mycelial growth or spore germination of test fungus. Acetone was selected as a dispersant in such an in vitro test because it is not only used as a solvent for fats, oils and waxes but also miscible with water. In this study to detect practically usable concentration of acetone in culture medium for test fungus, the results showed that both mycelial growth and spore germination of each test fungus were significantly inhibited on the culture media with 10% of acetone, while they were slightly inhibited on the culture media with 5% of acetone. Even though both mycelial growth and spore germination were influenced on the culture media with 5% of acetone, it is not considered that the use of culture medium with 5% of acetone make a mistake in assay of antifungal activity of fatty acids against phytopathogenic fungi.