• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.168-175
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• 2020

Recently, there has been an increasing need to expand the supply of renewable energy as a solution to greenhouse gas emissions. Therefore, as a measure to promote domestic renewable energy investment and gradual expansion, this study analyzed the investment value of renewable energy projects utilizing the unoccupied spaces of public enterprise's facilities and presented a strategic decision-making framework to support efficient national land development and government measures. The NPV was estimated to be 286 million won if the expansion of the facility was not considered, but it is reasonable to postpone the expansion decision because the value of -130 million won was calculated if the expansion was considered. On the other hand, the real-option value was estimated to be 444 million won, taking SMP uncertainty, expansion, and abandonment options into account, and an additional value of 288 million won was calculated from an analysis of the expansion project using the existing NPV analysis.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.235-241
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• 1997

This study was performed to investigate the behaviour of root zone environments under the control of soil temperature and tension of soil moisture near the root Bone of 'Kyoho' grapes tree grown on restricted root zone system in plastic greenhouse. Maximum diurnal air temperature inside plastic greenhouse ranged between 25.1 and 32.7$^{\circ}C$, and the average of nocturnal air temperature inside plastic greenhouse maintained at 18$^{\circ}C$ in winter season. Also the minimum diurnal relative humidity ranged between 50 and 55%, and the maximum nocturnal relative humidity ranged between 84 to 87%. At a depth of 15cm from soil surface, the average soil temperature maintained at 25.6$^{\circ}C$ for under-ground heating, and appeared to 17.4$^{\circ}C$ for unheated condition. Although the tension of soil moisture just after irrigation sharply decreased to pF 1.5, the tension of soil moisture at the depth of 15cm maintained at pF 2.0~2.2. It is suggested that the tension of soil moisture at the depth of 15cm might be used as the standard for the determination of irrigation set point. Effective drainage system is needed to prevent the spindly and succulent growth of vine trees grown in restricted root zone system.

• The Korean Journal of Pesticide Science
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• v.12 no.3
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• pp.236-242
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• 2008

Laboratory and greenhouse experiments were conducted to evaluate the effect of root zone application of some systemic insecticides for control of the brown planthopper (BPH), Nilaparvata lugens, as one of the management option to minimize the adverse effects and maximize the efficacy of insecticide application. Five systemic insecticides, namely, carbofuran, carbosulfan, diazinon, ethoprophos and imidacloprid, as granular formulation were placed in the root zone and measured the mortality, fecundity, and nymphal survivorship of the planthopper. Diazinon and ethoprophos did not show the significant mortality of the BPH. When the BPH were inoculated at the day of carbofuran treatment, adult mortality was shown almost 100% at seven days after treatment and BPH nymphs were remained very few on rice at 25 days after treatment. When carbofuran were placed 10 days before the BPH inoculation, it showed almost 100% adult mortality after one day, and no nymphs were found until 25 day after inoculation. Efficacy of carbofuran on BPH when applied in 10 day-old rice was higher than in 30 day-old rice. These results indicated that the root zone application of carbofuran can control N. lugens effectively with less adverse effect to the natural enemies inhabited on rice plants.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.185-199
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• 2017

Methane, which is emitted from natural and anthropogenic sources, is a representative greenhouse gas for global warming. Methanotrophs are widespread in the environment and play an important role in the biological oxidation of methane via methane monooxygenases (MMOs), key enzymes for methane oxidation with broad substrate specificity. Methanotrophs have attracted attention as multifunctional bacteria with promising applications in biological methane mitigation technology and environmental bioremediation. In this review, we have summarized current knowledge regarding the biodiversity of methanotrophs, catalytic properties of MMOs, and high-cell density cultivation technology. In addition, we have reviewed the recent advances in biological methane mitigation technologies using methanotrophs in field-scale systems as well as in lab-scale bioreactors. We have also surveyed information on the dynamics of the methanotrophic community in biological systems and discussed the various challenges pertaining to methanotroph-related biotechnological innovation, such as identification of suitable methanotrophic strains with better and/or novel metabolic activity, development of high-cell density mass cultivation technology, and the microbial consortium (methanotrophs and non-methanotrophs consortium) design and control technology.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.45-46
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• 2009

This study was carried out to identify the changes of EC during desalinization due to flooding in newly reclaimed saline soil. To do this, experimental plots were made of rotary tillage+water exchanging plot, flooding plot and rainfall flooding plot. In rotary tillage+water exchanging plot, drainage, rotary tillage and flooding were conducted at the interval of 7 days. In rotary tillage+water exchanging plot and flooding plot, plots were irrigated at the height of 10 cm. After 38 days desalinization, changes of EC values at top soil (0~20 cm) were as follows. In rotary tillage+water exchanging plot, EC decreased from $21.38dS\;m^{-1}$ to $2.16dS\;m^{-1}$ and in flooding plot, EC decreased from $13.97dS\;m^{-1}$ to $2.22dS\;m^{-1}$. In rotary tillage+water exchanging plot and flooding plot, EC values decreased below the EC criterion ($4.0dS\;m^{-1}$) of saline soil. In rainfall flooding plot, EC values decreased or increased according to amounts of rainfall and rainfall time. After 38 days, EC decreased from $16.7dS\;m^{-1}$ to $12.35dS\;m^{-1}$. In flooding plot, changes of EC due to soil depth were investigated. After 38 days desalinization, changes of EC due to soil depth were as follows. At 0~10 cm depth, EC value decreased from $13.08dS\;m^{-1}$ to $0.74dS\;m^{-1}$ (94.3% of salt was desalinized). At 10~20 cm depth, EC value decreased from $14.80dS\;m^{-1}$ to $3.69dS\;m^{-1}$ (75.2% of salt was desalinized). At 20~30 cm depth, soil was desalinized slowly compared with upper soil, EC value decreased from $13.57dS\;m^{-1}$ to $6.93dS\;m^{-1}$ (48.9% of salt was desalinized).

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.15-21
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• 2020

This study analyzes the results of applying the ISO19030 (hull and propeller performance monitoring method) standard to an actual 178 k bulk vessel. Recently, there have been many attempts to apply various energy reduction solutions to vessels to continuously strengthen GHG reduction regulations and secure maritime competitiveness. However, it is not easy to quantitatively analyze the performance of a ship. To resolve these problems, shipping companies, marine paint companies, ship owners, and transportation associations have appointed specialists and standardized the ISO19030 (standard of hull and propeller performance monitoring method) guidelines in 2016 after three years of continuous review. The ISO19030 standard provides methods to monitor hull and propeller performance quantitatively through standardized procedures, thus allowing ship managers to arrive at informed decisions for hull and propeller maintenance, and to evaluate energy-saving solutions and ship-maintenance efficiency. The ISO19030 standard provides a method of analyzing the ship's own performance by collecting the ship's operation and agency data and correcting its environmental and operating factors. In this paper, we apply the ISO19030 standard to three actual ships and propose the ISO19030 application result and the improvement point of the current ISO19030 standard.

• Journal of Korea Foresty Energy
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• v.25 no.2
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• pp.42-48
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• 2006

This study looked into the change of tree growth of five forest growth monitoring plots which were set up at the Undulyeong Hongchungun Kangwondo, and was accomplished to provide the basic data for the forest management calculating carbon storage and absorption in the Undulyeong area. Annual height and DBH growth were slowly progressed in the Pinus koraiensis, Larix kaempferi, and Pinus densiflora stand which were at young stage, but the growth rates of the other stands were lower than those young stands. The diameter class of the mixed forest and Quercus mongolica and Betala platyphylla stand was predicted to be similar as it is and those of Pinus koraiensis and Larix kaempferi stands were predicted to move to the upper diameter classes because of rapid growth rates of the those stands. As in the year 2005, total carbon storage of the Undulyeong model forest was increased by 155,000 TC(2.7%) compared with the previous year. During 2005, total carbon which was absorbed and stored according to growth of the forest was 166,174 TC and net carbon absorption (155,481 TC) increased by 2,736 TC (1.8%) compared with the previous year. Resultingly, the Undulyeong model forest is acting as a net sink and the net carbon absorption rate is slightly increasing recently.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.225-231
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• 2009

'Nokkwang' green pepper plants were grown in soil system (silty loam with pH 6.5) under the greenhouse, to determine the effects of subsurface drip irrigation (SDI) and subsurface drip irrigation plus aeration (SDIA) into root zone comparing with conventional surface drip irrigation (DI) in terms of water use efficiency, soil properties, and growth and fruit yield. Two drip lines per crop row were layed on the soil surface in DI system, buried at a depth of 20cm below the soil surface in SDI system, and also buried at a depth of20cm below the soil surface and aerated for 3minutes a hour during the daytime ($08:00{\sim}19:00$) by a air compressor in SDIA system. A automatic irrigation with starting point of -20kPa and ending point of -10kPa based on soil moisture contents was applied by controllers and electronic vacum soil moisture sensors. Reduction in soil moisture contents was delayed in SDI and SDIA, compared to DI. Irrigation amount applied in pepper cultivation was around 30% less in SDI than in DI. Electric conductivity and nitrate nitrogen content in the surface soil grown green pepper were significantly lowered in SSDI and SDIA, compared to DI. Better development of root system was observed in SDIA and SDI than in DI. Results showed that pepper fruit yield increased by 30% in SDIA and 22% in SDI in comparision with DI.

• Research in Plant Disease
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• v.17 no.2
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• pp.142-147
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• 2011

In order to develop a environmentally friendly control protocol for managing tomato leaf mold disease in the field, we employed bacteria- and fungi-based commercially available microbial preparations. The field experiment was conducted from April to July in 2010. Average incidence rates tomato leaf mold caused by Fulvia fulva were 13.1% at the two plastic houses located in Jangsung, Jeonnam area. Initially 11 microbial preparations were tested for antifungal activity against F. fulva in vitro. Among them, 7 selected preparations showed to be inhibited the mycelial growth of the fungal pathogen over 50%. Four microbes suppressed disease incidence as much 50% under greenhouse condition. Eventually in the field two microbial products including Bacillus subtilis GB-0365 and B. subtilis KB-401 respectively were showed control value up to 71.8% for four times sprays from 20 days to 70 days after transplanting. Furthermore, the control value of three times spray program demonstrated 79.3%. Efficacy of the three and four spray programs was more effective than that of non-spray control treatment. Our results indicated that adjustment of application method of commercially available microbial preparation could be used to control a target plant disease as an effective and efficient crop protection system for organic farming.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.263-272
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• 2012

The potential as natural herbicide of d-limonene natural agent was conducted on several weeds in a greenhouse and Sciyos angulatus in field condition. Herbicidal activity of foliar application at a concentration of 100 and 200 kg ai $ha^{-1}$ of d-limonene on seven weed species was completely killed in a greenhouse condition. Also, d-limonene at a concentration of 50 kg ai $ha^{-1}$ was completely killing on Abutilon theophrasti, Aeschynomene indica, Echinochloa crus-galli and Digitaria ciliaris 3 days after treatment. While pre-emergence treatment of d-limonene concentration of 12.5 to 200 kg ai $ha^{-1}$ showed not significant visible damages. Phytotoxic symptoms of d-limonene by foliar treatment were characterized by wilting and burn-down of leaves and stems followed by discoloration, finally, plant death. Crop selectivity at d-limonene concentration of 100 kg ai $ha^{-1}$ over to five main crops including Zea mays by foliar application was not at all. Field trial of foliar treatment with d-limonene 70 to 140 kg ai $ha^{-1}$ have effectively controled over 5~20 leaf stages of S. angulatus at the natural habitats. And herbicidal efficacy of foliar application on S. angulatus with carrier volume in field condition was increased with dose dependent manners. These results suggest that d-limonene is considered possible as herbicide, and may be further optimized for natural agent for environmental friendly natural herbicide.