• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.3
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• pp.200-208
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• 2012

Objectives: This study investigated the performance of three separate units of a portable photoionization detector (PID, ppb-RAE 3000) for measuring volatile organic compounds (VOCs) in a laboratory. Methods: A laboratory evaluation of the accuracy, precision, and inter-instrumental variance of three separate units of a portable PID (ppb-RAE 3000) was performed. The evaluation was based on the preparation of a test air sample of known toluene or ethylacetate concentration in a Tedlar$^{(R)}$ bag. The test air sample was monitored and data were logged consecutively by the three PIDs. A certified gas of 50 ppm toluene was also monitored during the test to ensure the reliability of the generated test air sample. Four different concentrations ranging from 0.1 to 2 TLV were used and a series of five measurements for each concentration level was performed. The accuracy was evaluated using National Institute for Occupational Safety and Health (NIOSH) criteria. Results: The results from the oldest ppb-RAE3000 unit among the three test units generally fell outside the NIOSH recommended accuracy criteria of ${\pm}25%$, whereas the other two units produced results which were acceptable at, or greater than, 25 ppm of toluene, or 0.5 TLV. These units also met the NIOSH criteria for some ethylacetate measurements but the results were not consistent. Conclusions: Considering the inconsistent performance of these ppb-RAE 3000 units, this device may not be appropriate for use as an alternative to the standard measurement methods. However, it can serve good survey instruments to identify exposure sources or concentration profiles. For all applications, the ppb-RAE 3000 should be used with frequent calibration checks, additional validation using a reference material, and careful maintenance.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.652-657
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• 2007

To make functional fresh-cut yam using natural spices, the water or the methanol extract was prepared from different kinds of natural spices including ginger, wasabi, black pepper, mustard, cinnamon, chinese pepper, garlic, thyme, rosemary, chamomile, and peppermint. The extraction yields were varied as spice sources and extraction solvents used. Among the water extracts, peppermint extract showed strong antithrombosis activity with 26-folds extended thrombin time, and the $IC_{50}s$ of the extracts from cinnamon and rosemary were $61.3{\mu}g/ml\;and\;84.3{\mu}g/ml$ in DPPH scavenging assay, respectively. Whereas, the antimicrobial activity of all water extracts was ignorable. Among the methanol extracts, the extracts from thyme, ginger, and cinnamon showed antimicrobial activity against yam putrefactive bacteria. Strong antioxidative activity was found in the extracts from cinnamon and thyme. Based on these results, the functional fresh-cut yam was prepared using the water extract from peppermint or cinnamon. The antioxidative and antithrombin activities in the fresh-cut yam were maintained at $4^{\circ}C$ for 24 hr. Our results suggest that the natural spices could be applied to production of functional fresh-cut yam.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.12
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• pp.1497-1502
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• 2013

When using hydrogen gas as an ecofriendly energy sources, it is necessary to conduct a safety assessment and ensure thereliability of the hydrogen pressure vessel against hydrogen embrittlement expected in the steel materials. In this study, by applying the in-situ SP test method, the gas hydrogen embrittlement behaviors in SA372 steel, which is commonly used as a pressurized hydrogen gas storage container, were evaluated. To investigate the hydrogen embrittlement behavior, SP tests at different punch velocities were conducted for specimens with differently fabricated surfaces at atmospheric pressure and under high-pressure hydrogen gas conditions. As a result, the SA372 steel showed significant hydrogen embrittlement under pressurized hydrogen gas conditions. The effect of punch velocity on the hydrogen embrittlement appeared clearly; the lower punch velocity case indicated significant hydrogen embrittlement resulting in lower SP energy. The fractographic morphologies observed after SP test also revealed the hydrogen embrittlement behavior corresponding to the punch velocity adopted. Under this pressurized gas hydrogen test condition, the influence of specimen surface condition on the extent of hydrogen embrittlement could not be determined clearly.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.438-443
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• 2017

The biological activity of crude polyphenol fractions (WphF, EphE, VphF, and SphF) extracted from Cedrela sinensis using hot water, ethanol, and enzymes such as Viscozyme and Shearzyme was examined in this study. The yield of VphF was the highest (43.44%) among all fractions. The total polyphenol and flavonoid content of the fractions were highest after ethanol extraction (447.98 and 337.49 mg/g, respectively). Fractions obtained after hot water and ethanol treatment showed high antioxidant activity. All fractions, except for WphF, showed a significantly higher ${\alpha}$-glucosidase inhibitory activity than the acarbose. EphF and WphF showed the high acetylcholinesterase inhibition activity. All fractions showed more than 50% tyrosinase inhibition activity at 2 mg/mL concentration. According to these results, the crude polyphenol fractions from C. sinensis showed high antioxidative, ${\alpha}$-glucosidase inhibitory, and tyrosinase inhibitory activities. This study suggests that crude polyphenol fractions from C. sinensis, especially the WphF and EphF fractions, are good sources of functional food.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.3
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• pp.27-27
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• 1987

The purpose of this study is to find the light intensity which induced maximum gathering rate and to observe the variation of the gathering rate both at daytime and night by using Sea-bass, Epinephelus septemfasciatus (Thunberg). An experimental tank (360 L×50 W×55H cm) was set up in a dark room. An illumination system was attached to the end of one side of the tank to control horizontal light intensity. Eight artificial light sources were prepared by combination of three with white light bulbs (10W, 60W, 100W) and eight filters. During the experiment water depth was maintained 50cm level in the tank. The tank was marked into six longitudinal sections each being 60cm long to observe the distribution of fish. The fish were acclimatized in dark condition for 50 minutes before the main experiment. Upon turning on the light, the number of fish in each section was counted 60 times every 30 seconds, and the gathering rate was obtained from the average number of fish in each section. The light intensity inducing maximum gathering rate was 24.13 lux (15.25~35.93 lux) at daytime and 0.41 lux (0.25~0.63 lux) at night. The variation of the gathering rate of fish in illumination time was great and did not show any definite pattern but fluctuated irregularly. Its different between daytime and night is remarkable.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.3
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• pp.137-143
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• 1987

The purpose of this study is to find the light intensity which induced maximum gathering rate and to observe the variation of the gathering rate both at daytime and night by using Sea-bass, Epinephelus septemfasciatus (Thunberg). An experimental tank (360 L$\times$50 W$\times$55H cm) was set up in a dark room. An illumination system was attached to the end of one side of the tank to control horizontal light intensity. Eight artificial light sources were prepared by combination of three with white light bulbs (10W, 60W, 100W) and eight filters. During the experiment water depth was maintained 50cm level in the tank. The tank was marked into six longitudinal sections each being 60cm long to observe the distribution of fish. The fish were acclimatized in dark condition for 50 minutes before the main experiment. Upon turning on the light, the number of fish in each section was counted 60 times every 30 seconds, and the gathering rate was obtained from the average number of fish in each section. The light intensity inducing maximum gathering rate was 24.13 lux (15.25~35.93 lux) at daytime and 0.41 lux (0.25~0.63 lux) at night. The variation of the gathering rate of fish in illumination time was great and did not show any definite pattern but fluctuated irregularly. Its different between daytime and night is remarkable.

• The Korean Journal of Food And Nutrition
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• v.28 no.2
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• pp.247-252
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• 2015

Three different Allium plants, including wild garlic (Allium monanthum Max; AMM), onion (Allium cepa L.; ACL) and green onion (Allium fistulosum L; AFL), have been widely used as spicy food in daily life. This study was attempted to investigate the properties of antioxidant, whitening and anti-wrinkle activities in water extracts in Allium plants. The antioxidant, whitening and anti-Wrinkle activities were evaluated by performing DPPH and ABTS radical scavenging activities, inhibitory effects on tyrosinase, and elastase, respectively. The water extract (10 mg/mL) of onion, wild garlic and green onion exhibited DPPH radical scavenging activities of 28.46%, 28.45%, and 15.91%, respectively. The inhibitory effects of tyrosinase activities by wild garlic, green onion, and onion were increased by heating the extracts at $90^{\circ}C$. Additionally, the wild garlic extract showed higher elastase inhibitory activity than those of other plant extracts. These results suggest that water extracts of Allium plants may be useful as potential sources of beauty foods due to higher antioxidant, anti-melanin and anti-wrinkle activities.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.498-504
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• 2002

Isoflavone (daidzein and genistein) contents, and antioxidative and fibrinolytic activities of seven commercial Korean cooking-with-rice soybeans, including Seonbikong, Chungtae, Gangnamkong, Whangtae, Geodoo, Seolitae, and Wooltalikong were investigated. Daidzein and genistein were not found in Selitae, nor was didzein in Gangnamkong and Geodoo. Total daidzein and genistein levels in Chungtae and Whangtae were 500 and 1550 mg per kg, respectively. Wooltalikong, Whangtae, and Gangnamkong had very high electron donation abilities, over 90%, but Seonbikong and Chungtae showed significantly lower activities. SOD-like activities were also the highest in Gangnamkong and Wooltalikong. Fibrinolytic activities in Seonbikong, Whangtae, and Gangnamkong were similarly strong. Fibrinolytic substances purified from protease inhibitors or activated under various pH or heat treatment conditions, were different among the soybean varieties. This study revealed that, although several cooking-with-rice soybeans were poor in isoflavones, Wooltalikong and Gangnamkong could be good sources for functional products due to their strong antioxidative activities, and heat- and acid-resistant proteolytic abilities.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.8-15
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• 2004

Seedling mechanization of lettuce is known to be difficult due to the small seed size and the irregular seed shape. The purpose of seed pelleting is to make seedling mechanization possible by enlarging the seed size. After that, it can reduce seedling and thinning labours and can also save seeds. According to the results, there were significant differences on the percent germination and day to 50% final germination in accordance with the pelleting polymer. Among the pelleting polymer, gemination of seeds using polynimyl alcohol (PVA) was generally smooth, and followed by polyvinyl pyrrolidone (PVP), hydroxyethyl cellulose (HEC), methyl cellulose (MC), and wteen 80. The germination rate was also different according to the pelleting particulate matters. Generally, percent germination and speed of seed using the mixture of diatomaceous earth, talc and calcium carbonate were higher and faster than using other polleting materials, respectively. Thus, it should be suitable pelleting particulate matter for the pelleting of lettuce seeds. On the other hands germination of seeds using limestone, calcium oxide and benonite were low. The seed size of lettuce after pelleting was 33 times as large as the raw seed size. During the process of seed pelleting, netrient addition induced the decrement on the germination and the delay of germination speed. Also, there was differences in the germinability of pelleted seeds in accordance with the addition of nutrient sources. MS medium was generally lower than monosodium phosphate in inhibition of seed germination. Germination of pelleted seeds after priming was higher than the seeds without the treatment, and also showed the trend of early germination.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.632-640
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• 2017

In order to understand the seasonal and geographical characteristics of environmental factors and distribution of Escherichia coli by salinity gradient due to precipitation, we investigated abiotic and biotic factors during four seasons from February 2013 to November 2015. The study area was divided into three different zones based on salinity gradient and geo-oceanographic characteristics. During the study period, water temperature, salinity, Chlorophyll a, and secchi-depth varied in the range of $8.5-26.1^{\circ}C$, 13.5-34.4 psu, $0.4-74.0{\mu}g\;L^{-1}$, and 0.5-10.0 m, respectively. Salinity was low at Zone I, which was influenced by water flux from Tae-hwa River, especially in 2014. Salinity was gradually increased (one-way ANOVA; p < 0.05) toward Zone III located offshore of the bay. The highest colony form of E. coli was detected at Zone I. E. coli maintained a relatively low level at Zone III during all seasons. E. coli was correlated with transparency (r = -0.36; p < 0.05) and salinity (r = -0.53; p < 0.01), implying that those parameters might play important roles in the proliferation of E. coli. These results indicated that E. coli were strongly affected by frequent rain (< 50 mm) around inner stations in Ulsan Bay of Korea.