• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.639-648
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• 2015

Some materials of fatty acids in the biodiesel affect the physical/chemical properties like density, kinematic viscosity, total acid number and oxidation stability by forming an organic fatty acid in combination with oxygen in the air. To solve the problem of the oxidative stability of biodiesel, various kinds of antioxidant has added and analyze the characteristics of the physical/chemical property changes by the addition of antioxidant. Oxidation stability increased by the increase of additives content. The TBHQ among the seven kinds of the additives showed the best performance. Also, 4 kinds of additives like propyl gallate, butyl-amine and pyrogallo has showed above 10 hr of oxidation stability at the addition of 500 ppm. In case of pyrogallo, this is not appropriate as an additive to suitable quality standards of total acid number. TBHA, DTBHQ of hydroquinone was satisfied with the quality standard of oxidation stability but the target of this research(above 10 hr) did not satisfied with oxidation stability. Propyl gallate is also a suitable at the quality standards of total acid number but it was shown not to be an appropriate to the additives due to increasing the total acid number by increasing of the content of additives at the addition of 500 ppm.

• The Korean Journal of Food And Nutrition
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• v.10 no.3
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• pp.350-359
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• 1997

The changes in pH, acid contents and microbial counts were investigated during fermentation of Baikkimchi, a kind of Kimchi without red pepper, and the major microbial groups were also isolated and identified. Immediately after the preparation of Baikkimchi(pH 6.15, acid contents 0.03%), its major microbial group was Gram negative rods, and was composed of Pseudomonas(55%), Enterobacter(40%) and Erwinia(5%). After 2 days of fermentation at 15$^{\circ}C$, the most predominant microbial group was changed to lactic acid bacteria. Lactic acid bacteria showed 1st, 2nd and 3rd stationary phase on its growth curve in 4, 12 and 50 days of fermentation, respectively. At the 2nd stationary phase of lactic acid bacteria(pH 3.51, acid contents 0.59%), the group was composed of Lactobacillus bavaricus(55%), Leuconostoc mesenteroides subsp. mesenteroides(42.5%) and Leuconostoc paramesenteroides(2.5%), while at the 3rd stationary phase(pH 3.40, acid contents 1.10%), that was Lactobacillus plantarum(65%) and Lactobacillus brevis(35%). The physiological and biochemical characteristics identified as Leuconostoc mesenteroides subsp. mesenteroides, Leuconostoc paramesenteroides, Lactobacillus plantarum and Lactobacillus brevis showed good agreement with the current taxonomic system, but those identified as Lactobacillus bavaricus showed some disagreements. The number of yeast was decreased wit the increase in the number of lactic acid bacteria. Yeast showed stationary phase in 30 days between the 2nd and 3rd stationary phase of lactic acid bacteria, and the group was composed of only gunus Saccharomyces.

• Journal of the Speleological Society of Korea
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• no.84
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• pp.53-66
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• 2008

오늘날 기후지형학은 지형학자들에게 가장 큰 논점이 되고 있다. 기후적인 외인적인 요인이 제1차적인 형성요인이며, 2차적으로 육수와 해수에 의한 내인적인 발달요인이 된다. 카르스트의 기후 적 접근은 1950년대부터 활발하게 주장되어 현대 진화의 광대한 연구에 가담하였다. 기후적인 작용에 의한 카르스트의 발달은 지대한 영향을 가져오지만 기온에 대한 카르스트의 발달에 대한 논쟁은 기존의 우 열대 저 한대 편향에서 많은 논쟁을 야기시키고 있다. 왜냐하면 한대와 온대, 열대와 중위도 카르스트 간에 어떠한 차이가 있지 않다고 규정짓고 있기 때문이다. 이에 따라 한반도에서도 제4기 동안에 형성된 해수면의 승강작용과 태백산맥의 융기작용에 따른 카르스트의 발달은 지형발달에 지대한 영향을 미친 결과 다수의 지표면 카르스트(카렌)와 지하 동공(동굴)의 발달이 형성되었다.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.261-266
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• 2005

Quaternary ammonium compounds(QACs) are some of the most commonly used antimicrobials. Antimicrobial polymers have been used as biomedical devices. In this Study, We synthesized new methacrylate monomers including quaternary ammonium moieties for preparation of contact lens, And also, we tested for antimicrobial activities against S. aureus, E. coli and P. aeruginosa. They showed much higher antimicrobial activities against all than the polymers of no including quaternary ammonium.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1180-1190
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• 2013

This study is to analyze femoral necks and lumbar spine bone mineral density in Korean men aged 60 or older 2,736 people, as well as to research in its relation to anthropometry, life style, diet, fracture history, family history of osteoporosis and medical history using data from Korea National Health and Nutrition Examination Survey (KNHANES)(the 2nd(2008) and 3rd(2009) year at the 1st survey, and the 1st(2010) year at the 5th survey). To express the strength of the associations, percent differences were calculated from multiple linear regression models using the formula ${\beta}{\times}$(unit/mesnBMD). Unit for continuous variables were chosen to approximate 1 standard deviation(SD). Prevalence of osteoporosis for 60-69, 70-79 and >80 old men were 6.7%, 15.8% and 31.4% respectively. The proportion of osteoporosis calculated for each age group in the femoral neck group was: 60-69 years old, 2.6%, 70-79years old, 8.2%, >80years old, 24.8%. For the lumbar spine group, the values were: 60-69 years old, 5.5%, 70-79years old, 11.3%, >80years old, 15.4%. In men aged 60 or older, lean mass greatly influenced bone density in the femoral neck and lumbar spine. Thus, to increase the lean mass would be an effective way to prevent osteoporosis in elderly men.

• Korean journal of applied entomology
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• v.23 no.1 s.58
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• pp.49-55
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• 1984

This study was carried out to investigate the biological performance of the brownplanthopper, Nilaparvata lugens Stal, reared on rice plants at different growth stages; maximum tillering, booting, heading with and without panicles, and milking. The results obtained are as follows: The rice plants at the maximum tillering stage gave the best in the longevity, oviposition period, and the total number of oviposited eggs for the macropterous females, and the worst with the booting stage. For the brachypterous females, however, the best results were obtained from the rice of which their panicles had removed after heading. There was no significant difference in the hachability of eggs and the developmental period of the nymphs in the next generation, but the nymphal mortality was the highest with the milking stage and the lowest with the maximum tillering and heading stage without panicles. The longest life span was shown in males derived on the maximum tillering stage, and the shortest for milking(macropterous type) or booting (brachypterous type) stages. Coefficientes of variances in longevity and number of eggs for the adults emerged from heading stage without panicles were lower than those with panicles intact, and such trend was more obvious in brachypterous adults, especially for the females. The biological performances of the BPH have close relationship with the translocated organic material at the feeding site which showed considerable difference with the growth stages of the rice.

• Korean Journal of Weed Science
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• v.14 no.4
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• pp.265-271
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• 1994

This study was conducted to determine the herbicidal activity, persistance, downward movement and effect on bentgrass of 7 dinitroaniline herbicides such as benefin [N-butyl-N-ethyl-2,6-dinitro-4-(trifluoromethyl) benzenamine], beslogine [N,N-dibutyl-2,6-dinitro-4-trifluoromethylaniline], prodiamine [2,4-dinitro-$N^3$,$N^3$-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine], pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine], trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl) benzenamine], ethalfluralin [N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl) benzenamine], and oryzalin [4-(diprop-ylamino)-3,5-dinitrobenzene-sulfonamide) together with bensulide [O,O-bis(1-methylethyl) S-[2-[(phenyl-sulfonyl) amino]ethyl]phosphorodithioate] and siduron [N-(2-methylcyclohexyl)-N'-phenylurea) as the control. In addition, distribution of pendimethalin and benefin into bentgrass was also determined. Prodiamine, benefin, and pendimethalin at the 1/16 dose of the recommended rate showed very high herbicidal activity($LD_{90}$) on Digitaria sanguinalis, but ethalfluralin and bensulide showed $LD_{90}$ at the 1/4 dose of the recommended rate, showing difference in herbicidal activities among dinitroaniline herbicides. All the herbicides except for pendimethalin had the lower herbicidal activity in sandy soil than that of clay-loam soil. Benefin, beslogine, prodiamine, oryzalin, bensulide and siduron persisted in the soil for about 50 days, but pendimethalin persisted in the soil for about 35 days, and trifluralin and ethalfluralin for about 25 days. Ethalfluralin, oryzalin and bensulide were the most mobile(downward movement) of the 9 herbicides studied. Less mobility was observed in the turfgrass condition than that of the bare soil. Beslogine bensulide prodiamine and benefin had no injury effect on bentgrass(Agrastis atolonifera L., penncross creeping bent grass). However, herbicides like oryzalin, trifluralin and pendimethalin reduced the dry weight of bentgrass by 12%, 30% and 40%, respectively. No significant difference in distribution of pendimethalin and benefin into inner part of leaves, surface and wax layer of bentgrass was observed, and thus it seems that different phytotoxic effect between pendimethalin and benefin may be attributed to different metabolism and mode of action.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.2
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• pp.95-103
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• 1981

This study was conducted to evaluate the effects of application of several soil amendment materials to an alluvial sandy soil on the rice growth and yield during the 1979. The materials used were the combinations of rice straw, rice hull, silicate fertilizer, red earth and zeolite. The results obtained were summarized as follows : 1. The application of soil amendment materials considerably increased the number of tillers, plant height and dry matter of rice plant. Particularly, the zeolite treated plot resulted in much better growth in the late stage rather than in the early stage. 2. The plots treated with silicate fertilizer, rice hull and zeolite significantly increased the rice yield and so did those with red earth statistically at 5 % level. However, it was not significant with rice straw. 3. By the application of these materials, the silica content in rice plant was continuously increased untill the heading stage, the nitrogen content was high at the maximum tillering stage and the panicle initiating stage and the phosphorus content was high at panicle initiating stage, which were censidered to be the factors of yield increase. However, in the straw treated plot, the contents of nitrogen, phosphorous and potassium were high, while the silica content was low in rice plant. 4. Further, soil pH, C. E. C., content s of organic matter and silicate in soil treated with those materials were increased after experiment. compared with in the soil before experiment.

• The Korean Journal of Quaternary Research
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• v.3 no.1
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• pp.87-101
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• 1989

The development of the Hantan river basin can be divided into three stages. The first stage include the ancient Hantan channel system prior to the Chongokni basalt which yield dates of about 0.6 mya from the K/Ar dating method. During this period the Baekuyri formation was formed. The Baekuyri formation is widely observed under the Chongokni basalt along the current river system. The second stage is the period when stream channels stayed on the top of the basalt plateau. Aggradation and deggradation were continued by meandering and braiding channel systems until major stream channel was formed. The currently remaining deposit on the top of the basalt was formed by lacustrine and fluvial systems in this period. During this period Pleistocene hominid was present on edge of water and flood plain and left Paleolithic material. This period was begun at the time of the final basalt flow dated about 300,000 BP. The third stage is designed for the time when the Hantan river channel was dropped down to a level from which the channel could not influence the top of the basalt any more No more deposit could be formed but erosion by surface water has been continued on the top of the basalt since then. The dropping of the Hantan river channel was probably not very long after the final flow of the basalt. Because of frost action and heavy concentrated precipitation in the basin area along with blocky and clumnar joint structure of the basalt, erosional process of the basalt is believed to have been carried out within a relatively short time. The lowering of the Hantan river channel was probably completed in a cycle of major fluctuation of world cimate. Also, the redclay on the top of the basalt is believed to have been formed during a warm period around 200,000 BP, which accords with the climatic change suggested above fair1y well. The Paleolithic materials in tile deposits fell accordingly into approximately same time period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6575-6580
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• 2013

Various modified SCR catalysts were prepared and tested to improve the strength of catalysts for use under severe conditions. The SCR catalysts were modified with a binder and dispersion agent, and tested at the fixed bed reactor. FT-IR and $H_2$-TPR were used to analyze the degree of hydrogen use and ammonia adsorption by the modified catalysts. In the case of the SCR catalysts coated with 2.3g of the binder, 4.7g of ethanol, and 0.1g of dispersion agent, the strength of catalyst was increased by approximately 12%. On the other hand, despite the enhancement of strength, the activities of the SCR catalysts were decreased by 2-10%. When the mixed solution composed of binder, dispersion agent and $SiO_2$ solution was precipitated on the catalyst, the $NO_x$ conversion of the catalyst was decreased slightly. The Bronsted acid site and Lewis acid site worked as the activators for the SCR reaction, and were decreased by $SiO_2$.