• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.337-348
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• 2003

The propagation mechanism of a detonation pressure with fully coupled charge is clarified and the blasting pressure propagated in rock mass is derived from the application of shock wave theory. The blasting pressure was a function of detonation velocity, isentropic exponent, explosive density, Hugoniot parameters, and rock density. Probabilistic distribution is obtained by using explosion tests on emulsion and rock property tests on granite in Seoul and then the probabilistic distribution of the blasting pressure is derived from the above mentioned properties. The probabilistic distributions of explosive properties and rock properties show a normal distribution so that the blasting pressure propagated in rock can be also regarded as a normal distribution. Parametric analysis was performed to pinpoint the most influential parameter that affects the blasting pressure and it was found that the detonation velocity is the most sensitive parameter. Moreover, uncertainty analysis was performed to figure out the effect of each parameter uncertainty on the uncertainty of blasting pressure. Its result showed that uncertainty of natural rock properties constitutes the main portion of blasting pressure uncertainty rather than that of explosive properties. In other words, since rock property uncertainty is much larger than detonation velocity uncertainty the blasting pressure uncertainty is more influenced by the former than by the latter even though the detonation velocity is found to be the most influencing parameter on the blasting pressure.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.315-322
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• 2008

In this study, a simple, effective, and sensitive method has been developed for the quantitative residue analysis of cyhalofop-butyl and its metabolite cyhalofop acid in water and soil when kept under laboratory conditions. The content of cyholofop-butyl and cyhalofop acid in water and soil was analyzed by first purifying the compounds through liquid-liquid extraction and partitioning followed by Silica gel (adsorption) chromatography. Upon the completion of the purification step the residual levels were monitored through high-performance liquid chromatography (HPLC) using a UV absorbance detector. The recoveries of cyhalofop-butyl from three replicates spiked at two different concentrations ranged from 82.5 to 100.0% and from 66.7 to 97.9% in water and soil, respectively. The limit of detection and minimum detection level of cyhalofop-butyl in water and soil was 0.02 ppm and 10 ng, respectively. The recoveries of cyhalofop acid ranged from 80.7 to 104.8% in water and from 76.9 to 98.1 % in soil. The limit of detection of cyhalofop acid was 0.005 ppm in water and 0.01 ppm in soil, while the minimum detection level was 2 ng both in water and soil. The half-live of cyhalofop-butyl was 4.14 and 6.6 days in water and soil, respectively. The method was successfully applied to evaluate cyhalofop-butyl residues in water and soil applied aj. 30% emulsion, oil in water (EW) product.

• Food Science of Animal Resources
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• v.22 no.1
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• pp.13-19
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• 2002

The natural sources extracted from green tea and pine needle were utilized to investigate the effects of extracts on free radical reaction, lipid oxidation and nitrite scavenging ability. The degree of lipid oxidation is very sensitive to kinds of oil emulsion reacted with iron sources and oxygen species. The antioxidants of extracts from green tea and pine needle were different depending on concentration of extracts, which were a lower TBARS value in 0.3% extracts concentration, compared to 0.1% extracts concentration. And also, the binding ability on iron sources was superior in hot water extracts, but oxygen scavenging ability was the lowest TBARS values in ethanol extracts. The hydroxyl radical scavenging ability of green tea and pine needle extracts had a little low TBARS value in 0.1% and 0.3% extracts concentration in deoxyribose. The ethanol extracts of pine needle were higher than those of hot water extracts on the basis of Fe$\_$2+/ ion content. The ascorbic acid content of green tea showed 14.3 mg/100g in hot water extracts and 16.7 mg/100 g in ethanol extracts. Electron donating ability of extracts showed difference depending on extracts concentration, which were higher in ethanol extracts than those of hot water extracts. The nitrite scavenging effects were tended to be different depending on pH value, however they were decreased overall as pH value was increased. Especially, the nitrite scavenging ability of 0.3% extracts from green tea and pine needle were the mosts effective in pH 1.2 and pH 3.0, which were showed 95% nitrite scavenging ability.

• Korean Journal of Pharmacognosy
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• v.41 no.3
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• pp.216-220
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• 2010

Obesity is an important risk factor that significantly increases mortality and disease rates in the cardiovascular disease, diabetes, and various diseases. So far, the most powerful way to inhibit fat absorption is pancreatic lipase inhibitors. In this study, we investigated the anti-obesity effect of the extract of Juniperus rigida. Juniperus rigida extract (JRE) had a inhibitory effect on pancreatic lipase activity ($IC_{50}$=8.63 ${\mu}g$/ml). In in vivo oil-emulsion loading test, this extract also inhibited the intestinal fat absorption. In addition, we measured inhibitory effects of JRE on activity of phosphodiesterase (PDE) and hormone sensitive lipase (HSL) among the important enzymes associated with lipolysis. JRE strongly inhibited PDE activity ($IC_{50}$=4.56 ${\mu}g$/ml), whereas inhibitory effect on HSL activity was very weak compared with orlistat. As a result, JRE inhibited the absorption of fat by inhibiting the activity of pancreatic lipase and induced lipolysis through inhibition of PDE activity. Therefore, we suggest that Juniperus rigida may be a potential therapeutic agent improving obesity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.231-236
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• 2021

The Aphid, Myzus persicae, and the bean bug, Riptortus clavatus, are major insects in crops. This study examined the insecticide susceptibility and phytotoxicity of insecticides dispersed using an Unmanned Aerial Vehicle (UAV, multi-copter) against the insects. Sulfoxaflor suspension concentrate (SC, 16X) on potato fields and etofenprox, methoxyfenzide suspo-emulsion(SE, 8X) on soybean fields were dispersed after deploying water-sensitive paper within the field to measure the distribution pattern and coverage index of the falling insecticide. Both insecticides showed a controlled mortality of 76.4% against aphids and 97.5% and 94.4% against the 2nd nymphal, and 5th nymphal stage of the bugs, respectively. The droplet distribution was less than 0.5mm, and coverage analysis revealed an inside and outside coverage of 3.1 and 1.6, respectively. The surrounding area was affected by insecticide spraying using a multi-copter. This study is expected to help expand UAV control and use it safely in the future.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.79-87
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• 1984

Herbicidal effects of alachlor to peanuts were observed under different formulations (granule containing 5.0% a.i. and emulsifiable concentrate containing 43.7% a.i.) and levels (granule with 3 and 6kg/l0a and emulsion with 300㏄/l0a) with the transparent polyethylene (P.E.) film mulching. Formulations and levels of alachlor did not affect emergence ratio, time of emergence and flowering, and early growth of peanuts such as the number of leaves and branches, length of branches; and shoot dry weight at 20 and 40 days after planting, but early growth was enhanced by P.E. film mulching. At harvest, weed dry weight was positively correlated with length of branches, but negatively correlated with the number of branches and shoot dry weight. Acalyphu australis and Chenopodium album were not effectively controlled by the application of alachlor and growth of C. album was retarded under P.E. film mulching. Portulaca oleracea and Digitaria sanguinalis were effectively controlled by alachlor, but they were not affected by P.E. film mulching. At harvest, D. sanguinalis, A. australis, and Echinochloa crus galli were predominant weeds in all treatments; persistence of alachlor may not be long enough to control even sensitive weeds to alachlor such as D, sanguinalis in the field of peanuts of which canopy development was relatively slow. Weed dry weight at harvest was negatively correlated with the number of pods and grain yield of peanuts. Among the yield components only the number of nods per plant was positively correlated with grain yield. Hana weeding after July 1 increased grain yield of Peanuts even in alchlor applied plots.