• Journal of the Korea Society for Simulation
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• v.22 no.1
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• pp.31-40
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• 2013

Recent development in science and technology has modernized the weapon systems of ROKN (Republic Of Korea Navy). Although the cost of purchasing, operating, and maintaining the cutting-edge weapon systems has been increased significantly, the national defense expenditure is under a tight budget constraint. In order to maintain the availability of ships with low cost, we need an efficient and scientific method for managing repairable parts. In this study, we propose a simulation model that computes the availability of ship's repairable parts. Our model is based on the METRIC (Multi Echelon Technique Repairable Item Control) model and extends to five sub-models to reflect the realistic situations that arise in the navy, such as planned maintenance, condemnation, lateral transshipment, and cannibalization. We have performed simulations to compute the availability of repairable parts while setting the part-level consistent throughout the five models and carried out two sensitivity analyses. The simulation results show the differences in the part availability in different models. The experiments confirm our claim that ROKN needs an inventory management system that captures the operational characteristics of the navy.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.482-488
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• 2017

Recently, weapon system has been highly regarding IM ability. Explosive is positively necessary in weapon system and it is principle component that must be improved for IM as the most hazardous material. RDX is one of energetic materials used the most at present since 1930s. It is being applied a lot to most of explosive in warhead and artillery and rocket propellants in these latter days due to its low cost and high energetic characteristics. However, it has a disadvantage which is more sensitive than some insensitive explosive like NTO, DADNE recently developed. To overcome this, researches have been continued about insensitive RDX and we are performing the study as well. In this study, we developed to apply reduced sensitivity RDX to pilot scale and mass production and we could confirm a result by shock sensitivity test.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.399-404
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• 2002

The fermented fruit and vegetable mixed broth was prepared by using bacteriocin-producing lactic acid bacteria to evaluate the possibility of developing isotonic beverage with anticariogenic activity. Optimum conditions were also established to produce bacteriocin by a mixed culture system consisting of Lc. lactis and Leu. mesenteroides in a fruit and vegetable mixture. Production of bacteriocin was not observed when both strains were simultaneously innoculated, but pH adjustment of the broth fermented by Leu. mesenteroides to nearneutral pH stimulated the production of bacteriocin by Lc. lactis. The concentration of sodium of the fermented broth was higher than those of commercial products. Color change of the fermented broth was not observed during storage. The fermented broth showed strong inhibitory effect against Streptococcus mutans which is an oral inhabitant with a cariogenic activity. Bacteriocin activity in the fermented broth was retained very stable for 4 weeks at 4$\^{C}$. The results indicated that bacteriocin-producing lactic acid bacteria can be used for the preparation of a Korean style thirst-quenching beverage containing bacteriocin.

• Applied Biological Chemistry
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• v.23 no.4
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• pp.211-217
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• 1980

Using Streptomyces chibaensis, which produces a strong inulin-hydrolyzing enzyme, the optimum cultural conditions and composition of the medium for the production of inulase were studied. 1. The highest enzyme activity was obtained at pH 7.5 after 84 hours culture at $30^{\circ}C$. 2. None of carbon source better than inulin was found. 3. $(NH_4)_2HPO_4$ and corn steep liquor were favourable inorganic and organic nitrogen sources for the production of inulase. 4. $KCl,\;MgSO_4\;and\;FeSO_4$ as the metallic salts were effective for the enzyme production at their concentrations of 0.01, 0.05 and 0.0001%, respectively. 5. The highest production of inulase was obtained from the medium of inulin 1.0% and corn steep liquor 2.0% concentrations, respectively.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.131-134
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• 2006

The culture conditions for the enhanced mycelial of Clavicorona pyxidata DGUM 29005 were investigated. The optimal temperature and pH for the mycelial growth were $24^{\circ}C$ and 5.0, respectively. It was shown that trehalose was the best supplement of carbon sources in Czapek-Dox medium as a minimal medium for enhanced mycelial growth. In general, inorganic nitrogen sources were better than organic ones for mycelial growth. Calcium nitrate was the best out of the inorganic nitrogen test. The appropriate phosphorous and vitamin were $Na_2HPO_4$ and p-aminobenzoic acid, respectively. After the mycelial of C. pyxidata DGUM 29005 was cultivated at $24^{\circ}C$ for 20 days in MEM broth(pH 5.0), the specific activities of both exomycelial and endomycelial enzymes were determined. Among the exomycelial enzyme assayed, the specific activity of laccase was much higher than those of other enzymes. However, little or no enzyme activities of ${\alpha}$-amylase, chitinase, lipase and pretense were found.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.206-211
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• 2014

Nutritional assessment of transgenic crops to improve safety evaluations is important for food production. An oxidative stress-tolerant rice was generated by stable insertion of the TC gene-a tocopherol cyclase isolated from tobacco-into the genome of a common variety of japonica colored rice. The nutritional composition of the brown rice grains from the transgenic TC line was compared with that of the parental rice cultivar Heugnambyeo and two different varieties of non-transgenic rice. The results indicate that the analyzed nutritional compositions of the brown grains from the transgenic TC line were within the range of values reported for other commercial lines, and measurements of nutritional compositions were equivalent to those of the non-transgenic rice.

• Korean journal of food and cookery science
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• v.30 no.6
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• pp.785-791
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• 2014

The antioxidative activities of beverages with water or ethanol extracts from Maegmundong (Liriope platyphylla) were investigated with free amino acid and mineral analysis, as well as saponin, total phenolics and flavonoid determination. Antioxidative activity was evaluated by electron donating ability and ABTS radical scavenging activity. There was only a small difference between water extract beverages and ethanol-extract beverages with respect to their electron donating ability and ABTS radical scavenging activity, although the total saponin, total phenolics and flavonoid were found to be greater in the ethanol extract beverages than in the water extract beverages. Three major free amino acids of the Magemundong beverages with water- or ethanol extract were asparagine (58.30, 60.68 mg%), methionine (15.10, 13.95 mg%, respectively) and proline (12.31, 14.00 mg%, respectively). The most abundant mineral in the Maegmundong beverage with water and ethanol extract was potassium (238.68, 244.32 mg%, respectively).

• Polymer(Korea)
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• v.36 no.1
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• pp.16-21
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• 2012

Organic-inorganic hybrid coating film using 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene (BTHFC) as a photochromic material was prepared under various reaction conditions such as the amounts of tetramethoxysilane (TMOS), various silane coupling agents, and solvent. It was found that color-fading speed and absorbance of the coating film was strongly dependent upon the polarity of silane coupling agent and solvent. In addition, the mole ratio of TMOS and methacryloyloxypropyltrimethoxysilane (MPTMS) was an important factor to determine color-fading speed and absorbance of the coating film. With increasing TMOS contents in coating film, the pencil hardness was increased. On the other hands, the transmittance of coating film was relatively decreased with the increase of TMOS.

• FLOWER RESEARCH JOURNAL
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• v.16 no.3
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• pp.174-178
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• 2008

This study was carried out to investigate the effect $GA_3$, moist chilling storage and priming treatments on seed germination of Caltha palustris var. membranacea. Percent germination was greatly improved by $GA_3$ treatment. However, no significant differences were observed among concentrations and soaking periods of $GA_3$. Optimum $GA_3$ treatment was one hour presoaking in a 100mg${\cdot}L^{-1}$ solution. Germination enhancing effect of moist chilling stroage was significantly greater than that of $GA_3$. Chilling treatment for five weeks resulted in the greatest percent germination of 60.3%. Unlike the role of $GA_3$ and moist chilling storage, no appreciable effect on seed germination was observed by the priming the seeds with either a $Ca(NO_3)_2 $ or $KNO_3$ solution.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.71-74
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• 2019

In this study, we fabricated two standard and inverted quantum dot light emitting diodes (QLEDs) using $TiO_2$ nanoparticles (NPs) with lower electron mobility than ZnO NPs as inorganic electron transport layer to suppress electron injection into the emitting layer. Current density was much higher for the inverted QLEDs than the standard ones. The inverted QLEDs were brighter, but showed low current efficiency due to the high current density. In addition, as the current density was higher, the driving voltage was higher, and the red shift was confirmed in the emission wavelength spectrum. The low current density in the standard structured devices showed that the possibility that $TiO_2$ NPs could suppress the electron injection in the QLEDs.