• Korean Journal of Medicinal Crop Science
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• v.11 no.2
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• pp.127-134
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• 2003

One hundred sixty species among Korean medicinal plants were tested on their antioxidative potentials. Antioxidants are useful materials which could be expected into development as food preservatives, health foods, cosmetics and drugs. Korean peninsula have many potential in antioxidant source which includes various medicinal herbs. It grounded on the fact that Korean medicinal plants have been used as folk therapy for long time and still do in oriental medicine. From the study, effective free radical scavengers compared with ${\alpha}-tocopherol\;of\;13.5{\mu}g/ml\;in\;RC_{50}$ were Geranium sibiricum, Geum japonicum, Geranium nepalense subsp. thunbergii and Paulownia coreana which showed $19.3{\mu}g/ml,\;22.5{\mu}g/ml,\;23.9{\mu}g/ml,\;and\;27.2{\mu}g/ml$, respectively, Acer mono and 38 plants showed strong potential in inhibition rate on linoleic acid oxidation (above 90%). In conclusion, we expect that the selected medicinal plants must be more studied as antioxidant and then developed as many industrial materials.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.47-55
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• 2008

According to the increase of power demand and expansion of downtown, it is necessary to install transformers additionally in operating substations and construct substations in residential area. But the public complaint has been increased due to the transformer noise of the substation. KEPCO has used a vibration preventing pad, various soundproof walls and an enclosure to transformers in outdoor substations, and a soundproof door, shutter and wind-path soundproof equipment in indoor substations to block the sound propagation from the transformers. But these noise reduction methods are not satisfied. It should be considered to reduce transformer noise itself. To shut out sound emitted from transformers, we developed a soundproof technology that wall up reinforcing bar by steel sheet. For the practical application of it, we analyzed the vibration characteristics of a transformer tank and reduction of noise according to soundproof plate. As a result, it is confirmed that the technology can reduce 11 [dB] of transformer noise.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.1
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• pp.24-28
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• 1989

This paper describes a fundamental method to suppress vibration of a structure under excitation by attaching a impact absorber. The influence of the shape of impact absorber, such as weight of add mass, impact clearance, contacting area and the exciting frequency on suppressing vibrations of the structure is investigated. The effectiveness of the proposed vibration absorber is demonstrated experimentally.

• Fire Science and Engineering
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• v.26 no.5
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• pp.41-47
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• 2012

As a core process in the manufacture of state-of-the-art industrial technologies such as semiconductor and LCD, a clean room is the most important process which can affect the performance and quality of products drastically. Nevertheless, scientific research on comprehensive safety measures from a fire protection standpoint is not being carried out in Korea. This study aims to derive measures to improve smoke control systems by identifying performance and problems of smoke systems installed in clean rooms as an LCD manufacturing process and analyzing fire and evacuation simulations considering several scenarios. As a result of analysis of fires and smoke in a clean roomas an LCD manufacturing process, it is found to be necessary to stop air handling units through interlocking in case of a fire and exhaust smoke out of the room through the top of FAB in consideration of buoyancy of smoke. It is also found to be necessary to install quick response sprinkler heads and accessories to accelerate the response time, because the heat-accumulating performance of sprinkler heads decreases in this application. Despite its low density of dwelling due to the automation process, clean room is characterized by an array of complex production equipment and working environment requiring dustproof clothes, which makes it difficult to acquire evacuation safety performance. Thus, thorough control of danger factors in processes and periodic education and training are required. It is also necessary to establish a level of domestic technologies equivalent to the level of standards of advanced countries in fire protection.

• Korean Journal of Construction Engineering and Management
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• v.6 no.5 s.27
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• pp.186-192
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• 2005

The purpose of this study is to find the reality of environmental management cost in construction projects and to suggest some policies in order that owners appropriate the environmental management cost reasonably in the construction budget for reducing the environmental pollution at job sites. We surveyed the actual state of appropriating and expending the environmental management cost over 122 construction sites. According to the results of the survey, while the appropriated rate of the environmental management cost was 0.59% of the total construction cost. the expended rate reached at 0.94%. When examining the antipollution facilities which were operated in job sites, the investment for equipment against air-pollution such as tire washer, dust-proof device was relatively higher than other antipollution equipment. As the method appropriating the environmental management cost, we concluded that a quantity-per-unit costing method is more reasonable than appropriating at a fixed rate of total construction cost considering that there is little correlation between total construction cost and the environmental management cost. To do so, antipollution facilities that must be examined at a design or estimation stage of a construction project should be prescribed by the law. Moreover, referenced cost data for the quantity-per-unit costing should be prepared and officially published.

• Korean Journal of Medicinal Crop Science
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• v.11 no.3
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• pp.236-245
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• 2003

The study was performed for elucidating angiotensin converting enzyme (ACE) inhibitory activity and comparing antioxidative activity of Panax ginseng extracts prepared at different conditions. Total phenolic content, inhibitory activity on ACE and antioxidative effects were tested on 10 ethanolic extracts and correlation coefficient between total phenolic content and physiological activity was calculated. Yield and total phenolic content of 50% ethanolic extract prepared at $85^{\circ}C$ exhibited the highest value as 42.52% and 0.82%, respectively. Among the fractions obtained from 50% ethanolic extract prepared at room temperature, water fraction showed the highest value in yield as 72.08% and ethyl acetate fraction did in total phenolic content as 6.59%. In the test on ACE inhibitory activity, 50% ethanolic extract obtained at room temperature indicated the strongest effect of 93.8% which was higher than 85.2% of commercialized ACE inhibitor and solvent fractions showed potent inhibitory activity in order of hexane fraction, diethyl ether fraction, ethyl acetate fraction, butanol fraction and water fraction at concentration of $4000{\mu}g/ml$. 50% Ethanolic extract prepared at $85^{\circ}C$ had the most potent inhibition effect on human LDL oxidation as 78.2% at $200{\mu}g/ml$ and the other extracts also did above 60%. Diethyl ether fraction and ethyl acetate fraction showed strong inhibition activity $(34.38%{\sim}78.13%)$ on LDL oxidation at concentration of $10{\sim}200\;{\mu}g/ml$. From the statistical analysis via SAS program, correlation coefficient between total phenolic content and ACE inhibitory effect was 0.6353 at P<0.05. Conclusively, this report showed that the most efficient extraction condition for elevating inhibitory activity on ACE and LDL oxidation, phenolic content and yield from Panax ginseng was 50% ethanol extraction at room temperature or high temperature condition. And Panax ginseng would be used for preventing hypertension or atheroscrelosis for man via inhibitory action on ACE and LDL oxidation.

• Korean Journal of Medicinal Crop Science
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• v.12 no.4
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• pp.321-327
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• 2004

Cortex of Ulmus davidiana var. japonica N. and Hemipteleae davidii P. have been used without classification according to countries as oriental medicine for treatment of various disorders. This study was conducted to elucidate the difference in antioxidant activity and total phenol content of these medicinal materials. Root cortex and trunk cortex of two medicinal plants were extracted with 80% ethanol $(at\;85^{\circ}C)$ and water (at room temperature), respectively. All of the extracts at $200{\sim}5\;{\mu}g/ml$, showed more effective scavenging activity on superoxide radical than ascorbic acid, and 80% ethanol and water extracts of Ulmus root cortex (URC) was more effective. Scavenging activities on DPPH radical of 80% ethanol extracts from URC and Ulmus trunk cortex (UTC) at 10 ${\mu}g/ml$, (41.4, 35.6%) were higher than those of the other six extracts and ${\alpha}-tocopherol\;(2.3{\sim}24.0%)$. Inhibitory activities on human low density lipoprotein (LDL) oxidation of 80% ethanol extracts from UTC and URC (84.3, 81.7%) at $10\;{\mu}g/ml\;(31.3{\sim}78.2%)$ were higher than those of the other six extracts and ${\alpha}-tocopherol$. However, antioxidant activities on linoleic acid peroxidation of all of the extracts were relatively lower than that ${\alpha}-tocopherol$. Total phenol content of 80% ethanol extract from URC was the highest value as 50.8% and that of water extract from HRC was the lowest as 5.6% among the extracts. From these results, it is suggested that Ulmus root cortex was the most effective in antioxidant activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.228-238
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• 2007

This study was conducted to increase sweetpotato utilization and to determine the vegetative value of sweetpotato tips by investigating the phenolic compounds, antioxidative effect in oil, electron donating ability, nitrite scavenging effect and ACE inhibition activities. The phenolic compounds present in sweetpotato tips are the gallic, chlorogenic, gentisic, caffeic, couramic and ferulic acid, which are 16-122 times higher compared to other vegetables such as spinach, soybean sprout, and perilla leaves. In each solvent extract, the total phenolic compounds (175.8mg/g) was composed of 55% EtOAc extraction and 39% BuOH extract, respectively. The results of induction period using the Rancimat method showed that the antioxidant activity of SP tips was higher than the tocopherol or BHT. The relative levels of each solvent extract in SP tips were as follows: EtOAc>BHT>BuOH>Tocopherol>Water>$CHCl_3$>Hexane. The peroxide value was measured every 5 days for 25 days during storage and results showed that the peroxide value, the tips, tuberous root and tocopherol were lower compared to spinach, soybean sprout and perilla leaves. Nitrite scavenging effects were excellent in sweetpotato tips, perilla leaves and soybean sprout, especially, inhibition rate of perilla leaves (72%) were superior to the others. In process of solvent extraction, activity of BuOH and water extractions were the best. ACE inhibition activity in sweetpotato tips was 1.5 times higher than in tuberous roots and $1.9{\sim}3.7$ times higher than in spinach, soybean sprout, perilla leaves.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.411-420
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• 2007

This study was conducted to increase sweetpotato utilization and to determine the vegetative value of sweetpotato tips by investigating the phenolic compounds, antioxidative effect in oil, electron donating ability, nitrite scavenging effect and ACE inhibition activities. The phenolic compounds present in sweetpotato tips are the gallic, chlorogenic, gentisic, caffeic, couramic and ferulic acid, which are 16-122 times higher compared to other vegetables such as spinach, soybean sprout, and perilla leaves. In each solvent extract, the total phenolic compounds(175.8 mg/g) was composed of 55% EtOAc extraction and 39% BuOH extract, respectively. The results of induction period using the Rancimat method showed that the antioxidant activity of SP tips was higher than the tocopherol or BHT. The relative levels of each solvent extract in SP tips were as follows: EtOAc>BHT>BuOH>Tocopherol>Water>$CHCl_3$>Hexane. The peroxide value was measured every 5 days for 25 days during storage and results showed that the peroxide value, the tips, tuberous root and tocopherol were lower compared to spinach, soybean sprout and perilla leaves. Nitrite scavenging effects were excellent in sweetpotato tips, perilla leaves and soybean sprout, especially, inhibition rate of perilla leaves(72%) were superior to the others. In process of solvent extraction, activity of BuOH and water extractions were the best. ACE inhibition activity in sweetpotato tips was 1.5 times higher than in tuberous roots and $1.9{\sim}3.7$ times higher than in spinach, soybean sprout, perilla leaves.

• Journal of Korea Water Resources Association
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• v.54 no.11
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• pp.903-913
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• 2021

In the flood season, the measurement of the river discharge has many restrictions due to reasons such as budget, manpower, safety, convenience in measurement and so on. In particular, when heavy rain events occur due to typhoons, etc., it is difficult to measure the amount of flood due to the above problems. In order to improve this problem, in this study, a method was developed that can measure the river discharge in a flood season simply and safely in a short time with minimal manpower by combining the functions of a drone and a surface velocity doppler radar. To overcome the mechanical limitations of drones caused by weather issues such as wind and rainfall derived from the measurement of the river discharge using the conventional drone, we developed a drone with P56 grade dustproof and waterproof performance, stable flight capability at a wind speed of up to 36 km/h, and a payload weight of up to 10 kg. Further, to eliminate vibration which is the most important constraint factor in the measurement with a surface velocity doppler radar, a damper plate was developed as a device that combines a drone and a surface velocity Doppler radar. The velocity meter DSVM (Dron and Surface Veloctity Meter using doppler radar) that combines the flight equipment with the velocity meter was produced. The error of ±3.5% occurred as a result of measuring the river discharge using DSVM at the point of Geumsan-gun (Hwangpunggyo) located at Bonghwang stream (the first tributary stream of the Geum River). In addition, when calculating the mean velocity from the measured surface velocity, the measurement was performed using ADCP simultaneously to improve accuracy, and the mean velocity conversion factor (0.92) was calculated by comparing the mean velocity. In this study, the discharge measured by combining a drone and a surface velocity meter was compared with the discharge measured using ADCP and floats, so that the application and utility of DSVM was confirmed.