• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.1
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• pp.98-110
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• 2015

Recently, a validation research of maneuvering and attitude control logics of a spacecraft under a ground condition is getting increase by using operating simulators with compact and precise components. For that, a cold gas propulsion system is generally used for maneuvering and attitude control of spacecraft ground simulators for its simplicity and a high reliability. In the present study, major design parameters of a cold gas propulsion system are derived to meet mission requirements based on conceptual design results of a simulator. And additionally, commercial components with proper specifications are selected for system assembly.

• Korean Journal of Construction Engineering and Management
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• v.6 no.2 s.24
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• pp.129-138
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• 2005

The purpose of this study is to assess economic effects for an advanced technology-based HVAC system. The study has been performed using LCC technique for the economic analysis. Data for LCC analysis are collected from estimation and interview of estimators and maintenance experts of buildings. Based on the LCC analysis, the economic effect of a new HVAC system has been predicted as follows : for the investment during 15 years of study period, (1) $21.6\%$ of LCC saving is predicted, (2) return rate for the investment is 4.8 times in case of new construction, and 14.4 times in case of building remodelling.

• Journal of Life Science
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• v.21 no.3
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• pp.468-472
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• 2011

DNA marker is a powerful tool for plant genetics and breeding. In this study, 995 SSR markers were employed with chilling resistant cucumber, known as 'NC76', and chilling susceptible cucumber, known as 'GY14'. Using 2% agarose gel electrophoresis, 145 SSR markers were identified as length variation markers between 'NC76' and 'GY14'. The SSR markers that showed no length polymorphism were then screened using high resolution melting analysis technique and additional 30 polymorphic SSR markers were identified. As a preliminary evaluation for mapping, 20 markers among these 175 markers were employed to a $F_2$ population of 'NC76' x 'GY14' cross. Linkage analysis revealed 13 markers that joined into six linkage groups and seven markers that remained unlinked. This result indicates that these 175 markers could be used for construction of a genetic map using a cross between 'NC76' and 'GY14' for further investigation in developing markers related to resistance to chilling in cucumbers.

• Korean Journal of Plant Taxonomy
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• v.36 no.2
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• pp.153-161
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• 2006

Two Unrecorded species from Jeju Province are reported: Maesa japonica of Maesaceae which is unrecorded family and Cardamine tanakae of Brassicaceae. Monotypic family Maesaceae, is distinguished from Myrsinaceae and Primulaceae by having pedicels with a pair of bracteoles, flowers without staminodia, semi-inferior ovary and indehiscent fruits with many seeds. M. japonica is readily distinguishable from M. salicifolia in China and M. montana var. formosana in Taiwan and Japan by shapes of blades, corolla and bracteoles, the presence/absence of serrulation of leaf margins, ratio of length of corolla tube and corolla lobes, feature and color of fruit surface. C. tanakae is most similar to Korean endemic C. glechomifolia in morphology, however, the two taxa are readily distinguishable by the number of leaflets of cauline leaves, size of terminal leaflets, number of flowers per inflorescence, the presence of whitish hairs on ovary and fruits.

• Journal of Bio-Environment Control
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• v.18 no.2
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• pp.137-141
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• 2009

This experiment was investigated to effect of divided rhizome size and medium type on survival rate and growth of wasabi for 60 days in controlled growth room. In divided rhizome size of 5mm above, survival rate was 100% and their growth (plant height of 12cm and leaf number of 3${\sim}$4 per plant) was good at 30 days after wrapped-sphagnum treatment. Plant height was 20cm above and number of leaves increased in 1-2 per plant at 60 days after treatment. Survival rate and growth didn't show any effect on plant regulator of root-tone. In inorganic media (saprolite and aerated light stone) treatment, survival rate of wasabi in divided size of 5${\sim}$10mm showed 83% or above at 30 days in deep flow culture. Growth did not show significant difference of inorganic support media treatments. Therefore, it is possible for divided rhizome size of 5mm above to do production of seedlings by acclimatize for 30 days in hydroponics under controlled growth chamber.

• Food Science and Preservation
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• v.16 no.4
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• pp.562-566
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• 2009

We investigated the natural antimicrobial activities of Capsella bursa-pastoris water, methanol, and ethanol extracts. Antimicrobial activities of these extracts and sodium benzoate on Bacillus cereus, Staphylococcus aureus, and Escherichia coli were compared. The inhibition zone diameters of the methanol and ethanol extracts of Capsella bursa-pastoris were 13-20 mm and 12-20 mm, respectively, which were larger than those of sodium benzoate (11-15 mm). The minimum inhibitory concentrations of Capsella bursa-pastoris methanol and ethanol extracts were 12.5-20 mg/mL. These results indicate that Capsella bursa-pastoris methanol and ethanol extracts can be used as natural antimicrobial agents.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.3
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• pp.226-232
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• 1981

To clarify the relationship between rice cool injury and the contents of silica and phosphorus in the soils and the rice plant, the investigation was carried out at ripening stage of rice from the different altitudes with different varieties throughout Yeongnam area. The rate of fertilized spikelets were decreased with elevation increase and the situation was distincted in the Japonica cross Indica hybrid varieties. The higher rates of $SiO_2/P_2 O_5$ content in the leaves and stems or lower rates of that in the soils show the higher fertilization rates. The result seems to be caused by the different solubility and uptakes of silica and by the different availability and transformation of phosphorus. A positive correlation was observed between the content of silica in rice plant and the fertilization rates. The fertilization rate in Japonica varieties was higher than that of Indica cross Japonica hybrid varieties in the case of the same content of silica in plant as far as observed, but the increasing rate of fertilized grains due to increase of silica content was prominented in the hybrid varieties which probably demand more silica. Within the certain limit of silica and phosphorus content in rice plant, the more uptaking of silica might lessen the cool injury.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.129-136
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• 2011

Microorganisms are the main causative factors of pulpal and periapical diseases, therefore successful endodontic treatment is depend on the effective elimination of intracanal bacterial populations. Many studies have been reported antimicrobial effect of Allyl isothiocyanate (AIT) which the principle ingredient of Horseradish (Armoracia rusticana) root extracts. The purposes of this study are to evaluate the antimicrobial effectiveness of Horseradish root extracts against Enterococcus faecalis in root canals of extracted human teeth and compare to sodium hypochlorite (NaOCl). Extracted human mandibular premolar root canals were infected with E. faecalis for 21 days, and then irrigated with Horseradish root extracts, NaOCl solution and saline. After canal irrigation, first samples (S1) were taken. After first sampling, the canals were additionally incubated 7 days, and then second samples (S2) were taken. The samples were inoculated on EHI agar plate to determine the colony forming units (CFU). 1. Mean values of CFU in S1 were $5.815{\times}10^3$ CFU/ml at Horseradish groups, and $3.465{\times}10^3$ CFU/ml at NaOCI groups. There was no statistically significant differences (p=0.086). 2. Mean values of CFU in S2 were $3.100{\times}10^3$ CFU/ml at Horseradish groups, and $5.252{\times}10^5$ CFU/ml at NaOCI groups. There was statistically significant difference (p<.05). 3. There was no statistically significant differences (p=0.076) between S1 and S2 at Horseradish groups in the mean values of CFU. However, there was statistically significant differences (p<.05) between S1 and S2 at NaOCI groups in the mean values of CFU.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.168-178
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• 2010

Objective : The aim of this study was to determine the antimicrobical effect of horseradish root extracts against Enterococcus faecalis and Fusobacterium nucleatum isolated from oral cavity compared with reference strain, and compared with that of chlorhexidine. Method : Horseradish root extracts and chlorhexidine were sequentially diluted and tested against anaerobes(E. faecalis, F. nucleatum) isolated from children's oral cavity. The microbes were anaerobically incubated and the minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) were detected. Results :1. Horseradish root extracts showed antimicrobial effect against E. faecalis isolated strain at same or slightly higher concentration compared with MIC of reference strain. 2. $625.0\sim1,250.0{\mu}g/ml$ horseradish root extracts showed similar antimicrobial effect with chlorhexidine($7.8\sim15.6{\mu}g/ml$). 3. Horseradish root extracts showed antimicrobial effect against F. nucleatum isolated strain at same or slightly higher concentration compared with MIC of reference strain. 4. $78.1\sim312.5{\mu}g/ml$ horseradish root extracts showed similar antimicrobial effect with chlorhexidine($7.8\sim15.6{\mu}g/ml$). Conclusions : The results of this study confirm that horseradish root extracts has antimicrobial effect against anaerobes isolated from oral cavity as well as reference strain. And we found the potential of horseradish root extracts as a canal irrigant or disinfectant.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.355-365
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• 2014

It has been unclear whether the diamondback moth, Plutella xylostella can overwinter in Korean field conditions. This study determined overwintering conditions of P. xylostella by conducting field exposure tests based on its cold tolerance and monitoring overwintering populations by direct examination of overwintering larval habitats and capturing adults with sex pheromone traps. In addition, the overwintering populations were analyzed using polymorphic genetic markers to trace their sources. When all immature stages of P. xylostella were exposed to $-5^{\circ}C$, which was the temperature much above their supercooling points, they significantly suffered with direct cold injuries, where larval stage was most tolerant to the cold injury. However, the exposure to $5^{\circ}C$ for a long period (4 weeks) did not give any significant cold injury to nonfeeding stages, while this treatment gave lethality to larval stage without diet. When all developmental stages of P. xylostella were exposed to open field conditions during winter, they exhibited significant decreases of survival rates. However, some protected and indoor conditions reduced the cold injuries and the diet provision significantly increased larval survival rates. Adult monitoring with sex pheromone during winter period indicated that the first captures were observed at similar periods at different locations (${\approx}260$ Km apart). The overwintering adults were captured until early April. Genetic variation of these overwintering populations was analyzed with polymorphic molecular markers, indicating significant genetic divergences among the overwintering populations. This study indicates that P. xylostella can overwinter in southern Korean fields or some protected greenhouses with host plants.