• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.5
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• pp.59-66
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• 2020

Recently, cultivation and management technologies have been needed to adapt due to climate change, which is causing abnormal weather conditions. One technique is to increase the utilization of evergreen broad-leaved species with high ornamental value. A total of five treatments were installed (1m×22.5m), including 60g/㎡ and 80g/㎡ using two types mulching material with an overlapping and hole-drilling mulching method and these were compared to un-mulching treatment a total of planted 92㎡ attheWol-aTestSiteForestattheForestforBiomaterialsResearchCenterinJinju-si, Gyeongsangnam-dofor 10monthsusing3-years-oldQuercusglaucaThunb. In comparison with the control site, the 60g/㎡ overlapping method was about 1.9 times higher than the root collar diameter, but there was no statistical significance between the treatments. Healthy seedlings were found to meet these conditions due to high biomass values and below and T/R ratios of 3.0 or lower and H/D ratios of 7.0 or lower. Comparing the values of LWR, SWR, and RWR, which can be evaluated for seedling due to the mulching treatments, as compared to the control, the growth of the ground areas including leaves and stems was enhanced, but the growth of the underground areas containing roots tended to have high control values. Based on this, the SQI value, which can be evaluated for the comprehensive quality of seedlings, was found to be significantly different between the control site and the mulching treatment sites, confirming that the growth and growth improvement effects were achieved with mulching treatments. The chlorophyll content analysis showed that there was a significant difference from the control site, and it was judged that weed generation in the control acted as an environmental stress, causing a decrease in chlorophyll content. It was found that the overlapping 80g/㎡ of polypropylene mulching material generated about 4 times fewer weeds than the control, and the manpower required for the mulching test field and weeding were equal at 3.3 people/100㎡/1 day. Mulching treatments have demonstrated a significant difference in the promotion of growth and quality of the seedlings and are judged as an alternative that can reduce the economic burden incurred by the purchase of the supplies and the manpower required to weed forestry plantations.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.123-133
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• 2011

The objective of this study was to find optimal nutrient condition of container seedling production of two tropical species for high seedling quality. This study was conducted to investigate photosynthesis, chlorophyll fluorescence, chlorophyll contents, and growth performances of container seedlings of Eucalyptus pellita and Acacia mangium growing under four different fertilization treatments (Con., $0.5\;g{\cdot}l^{-1}$, $1.0\;g{\cdot}l^{-1}$, and $2.0\;g{\cdot}l^{-1}$ fertilization). E. pellita showed outstanding photosynthetic capacity, photochemical efficiency, and chlorophyll contents at $1.0\;g{\cdot}l^{-1}$ fertilization. Meanwhile, E. pellita showed the highest photosynthetic capacity, photochemical efficiency, and chlorophyll contents at $2.0\;g{\cdot}l^{-1}$ fertilization, as fertilization rate were increased, those of A. mangium increased. Like physiological characteristics, Both E. pellita at $1.0\;g{\cdot}l^{-1}$ fertilization and A. mangium at $2.0\;g{\cdot}l^{-1}$ fertilization were higher root collar diameter, height, biomass, and seedling quality index than other treatments. These results showed that E. pellita at $1\;g{\cdot}l^{-1}$ fertilization and A. mangium at $2.0\;g{\cdot}l^{-1}$ fertilization is optimal nutrient condition, respectively. Moreover, fertilization rate controlling is very important for growth and seedling quality of container seedling.

• 대한공업교육학회지
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• v.38 no.1
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• pp.1-27
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• 2013

The purpose of this study was to find out the areas and their constitute elements of new apprenticeship through the expert of vocational education to improve the growth potential in the field of industry. Through the three times Delphi research process final composing areas and elements(total 6 areas and 41 sub-elements) of new apprenticeship were extracted. Followings are specific study results of 41 sub-elements for the 6 areas. In area A(Technology Skill aspect) total nine sub-elements were deducted as follows. Technology skill's field appling ability, new technology skill's acquisition, quality assurance ability, research development ability, material management using ability, problem solving ability, core technology skill understanding ability, idea's imagery expressing ability, creative design ability. In area B(Institutional aspect) total five sub-elements were deducted as follows. Flexible human material support, precise division of works, objective result assessment, institutionalization of responsibilities and liabilities between teacher and student, institutionalization of duty invention reward. In area C(Affective aspect) total eight sub-elements were deducted as follows. Manners and cooperation between teacher & student and peer, values for job, basic attitude for technology, job ethic sense, respect of other organization, active action to organization change, attitude of technology successor, service mind. In area D(Self-improvement aspect) total nine sub-elements were deducted as follows. Self evaluation and reflection, cultivate of organization understanding, career planning and developing ability, sound philosophy of life, communication ability, decision making ability, prepare of individual competence enhance system, self-control ability improvement, reaction of unexpected situation. In area E(Knowledge aspect) total four sub-elements were deducted as follows. Basic knowledge of relevant area, knowledge of new technology & preceding technology, fusion and relocation of knowledge, practical knowledge. In area F(Environmental aspect) total six sub-elements were deducted as follows. Awareness of business environment, understanding of education and practice environment, understanding of apprenticeship's business demand, connectivity of region community, adapt ability of labor market's change, awareness of society environment change.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.23-29
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• 2005

Shoots of balloon flower (Platycodon grandiflorum A. DC.) derived from in vitro germinated seeds were cultured on MS medium containing $0.1\;\cal{mg/L}$ NAA under various photosynthetic photon flux (PPF) 33, 66, and $99\;{\mu}mol\;m^{-2}s^{-1}$ with or without membrane filter. Number of air exchanges per hour (NAEH) of the culture vessel with membrane filter on the lid was $4.9 h^{-1}$ and that without membrane filter was $0.1 h^{-1}$ Plantlets grown in $4.9 h^{-1}$ NAEH showed greater growth than in $0.1 h^{-1}$ NAEH. According to increase of PPF, plantlets growth decreased in $0.1 h^{-1}$ NAEH while it increased in $4.9 h^{-1}$ NAEH. At the same PPF, fresh weight and sugar content in plantlets in $4.9 h^{-1}$ NAEH were above 1.9, 2.0 times higher than those in $0.1 h^{-1}$ NAEH, respectively. Also they were enhanced in $4.9 h^{-1}$ NAEH by increase of PPF whereas no significance in $0.1 h^{-1}$ NAEH. The percentage of water content of plantlets in $4.9 h^{-1}$ NAEH was $4.2\~5.5\%$ lower than those in $0.1 h^{-1}$ and no difference in PPF. The content of total chlorophyll in plantlets in $4.9 h^{-1}$ NAEH was higher $0.27\~0.79\;\cal{mg/g}$ F.W. than that in $0.1 h^{-1}$ NAEH. By increase of PPF, it was decreased in $0.1 h^{-1}$ NAEH while had no significant difference in $4.9 h^{-1}$ NAEH. Guard and subsidiary cells of leaves in $4.9 h^{-1}$ NAEH were more developed than in $0.1 h^{-1}$ NAEH. Especially, in $99\;{\mu}mol\;m^{-2}s^{-1}$ leaves in $0.1 h^{-1}$ NAEH had undeveloped subsidiary cells and wide open stomata whereas those in $4.9 h^{-1}$ NAEH had well-developed subsidiary cells.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.3
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• pp.254-259
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• 2014

A pressurized heavy water reactor (PHWR) core has 380 fuel channels contained and supported by a horizontal cylindrical vessel known as the calandria, whereas a pressurized water reactor (PWR) has only a single reactor vessel. The pressure tube, which is a pressure-retaining component, has a 103.4 mm inside diameter ${\times}$ 4.19 mm wall thickness, and is 6.36 m long, made of a zirconium alloy (Zr-2.5 wt% Nb). This provides support for the fuel while transporting the $D_2O$ heat-transfer fluid. The simple tubular geometry invites highly automated inspection, and good approach for all inspection. Similar to all nuclear heat-transfer pressure boundaries, the PHWR pressure tube requires a rigorous, periodic inspection to assess the reactor integrity in accordance with the Korea Nuclear Safety Committee law. Volumetric-based nondestructive evaluation (NDE) techniques utilizing ultrasonic and eddy current testing have been adopted for use in the periodic inspection of the fuel channel. The eddy current testing, as a supplemental NDE method to ultrasonic testing, is used to confirm the flaws primarily detected through ultrasonic testing, however, eddy current testing offers a significant advantage in that its ability to detect surface flaws is superior to that of ultrasonic testing. In this paper, effectiveness of flaw detection and the depth sizing capability by eddy current testing for the inside surface of a pressure tube, will be introduced. As a result of this examination, the ET technique is found to be useful only as a detection technique for defects because it can detect fine defects on the surface with high resolution. However, the ET technique is not recommended for use as a depth sizing method because it has a large degree of error for depth sizing.

• Research in Plant Disease
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• v.21 no.4
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• pp.297-308
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• 2015

In order to control seed-borne diseases, we obtained extracts from commercial fermented food products of Kimchi, Gochujang, Doenjang, Ganjang and Makgeolli and their suppressive effects against seed-borne diseases were studied. In addition, the suppressive effects of bacterial strains isolated from the fermented foods were screened in vitro and in vivo. Among fifty food extracts, twenty food-extracts suppressed more than 92% incidence of seedling rots in vitro and seven food extracts increased 58.3-66.8% of healthy seedling in the greenhouse. Among 218 isolates from the fermented foods, 29 isolates showing high antifungal activity against seven seed-borne fungal pathogens were selected. Among 29 isolates, 13 isolates significantly reduced seedling rot and increased healthy seedlings. Sixteen isolates with high antifungal activity and suppressive effect against sesame seedling rots were identified by 16S rRNA sequencing. Fourteen of sixteen isolates were identified as Bacillus spp. and the other two isolates from Makgeolli were identified as Saccharomyces cerevisiae. It was confirmed that B. amyloliquifaciens was majority in the effective bacterial population of Korean fermented foods. In addition, when the bioformulations of the two selected effective microorganisms, B. amyloliquifacien Gcj2-1 and B. amyloliquifacien Gcj3-1, were prepared in powder forms using bentonite, kaolin, talc and zeolite, talc- and kaolin-bioformulation showed high control efficacy against sesame seed-borne disease, followed by zeolite-bioformulation. Meanwhile control efficacy of each bentonite-bioformulation of B. amyloliquifacien Gcj2-1 and B. amyloliquifacien Gcj3-1 was lower than that of bacterial suspension of them. It was found that the selected effective microorganisms from Korean fermented foods were effective for controlling seed-borne diseases of sesame in vitro and in the greenhouse. We think that Korean fermented food extracts and useful microorganisms isolated from the extract can be used as bio-control agents for suppressing sesame seed-borne diseases based on above described results.

• Research in Plant Disease
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• v.21 no.4
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• pp.280-289
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• 2015

Maize (Zea mays L.) is an economically important crop in worldwide. While the consumption of the maize is steadily increasing, the yield is decreasing due to continuous mono-cultivation and infection of soil-borne fungal pathogens such as Fusarium species. Recently, stalk rot disease in maize, caused by F. subglutinans and F. temperatum has been reported in Korea. In this study, we isolated bacterial isolates in rhizosphere soil of maize and subsequently tested for antagonistic activities against F. subglutinans and F. temperatum. A total of 1,357 bacterial strains were isolated from rhizosphere. Among them three bacterial isolates (GC02, GC07, GC08) were selected, based on antagonistic effects against Fusarium species. The isolates GC02 and GC07 were most efficient in inhibiting the mycelium growth of the pathogens. The three isolates GC02, GC07 and GC08 were identified as Bacillus methylotrophicus, B. amyloliquefaciens and B. thuringiensis using 16S rRNA sequence analysis, respectively. GC02 and GC07 bacterial suspensions were able to suppress over 80% conidial germination of the pathogens. GC02, GC07 and GC08 were capable of producing large quantities of protease enzymes, whereas the isolates GC07 and GC08 produced cellulase enzymes. The isolates GC02 and GC07 were more efficient in phosphate solubilization and siderophore production than GC08. Analysis of disease suppression revealed that GC07 was most effective in suppressing the disease development of stalk rot. It was also found that B. methylotrophicus GC02 and B. amyloliquefaciens GC07 have an ability to inhibit the growth of other plant pathogenic fungi. This study indicated B. methylotrophicus GC02 and B. amyloliquefaciens GC07 has potential for being used for the development of a biological control agent.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.529-534
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• 2010

Occurrence of wilted symptom in watermelon plant ($Citrullus$ $lanatus$ L.) is known to be caused by physiological disorder. The symptom results in the loss of fruit production and thus the economical loss of watermelon growers. The incidence of symptom is often found from the middle of March to the end of May in the major watermelon crop production areas of Korea (i.e. Uiryeong, Gyeongnam (lat $37^{\circ}$56'64"N, long $126^{\circ}$99'97"E)). Despite of extensive information about the physiological disorder, little study has been conducted to understand a relationship between the wilted symptom and accompanying environment factors (e.g. temperature). This study aimed to investigate effects of environmental conditions amended by a forced-ventilation system on physiological characteristics of watermelon and incidence of the wilted symptom. Watermelon plants were grown from January to May, 2009 with either the forced-or natural-ventilation treatment in a greenhouse located in the Uiryeong. In the result, the forced-ventilation treatment decreased the air, leaf and root-zone temperature approximately $4.5^{\circ}C$, $5^{\circ}C$ and $3^{\circ}C$, respectively, compared to the natural-ventilation. The fruit growth rate was maximized twice during the entire growing period. The higher rate of fruit growth was observed under the natural-ventilation than the forced one. Maximization of the fruit growth rate (approximately 430 g per day) was first observed by 12 days after fruiting under the natural-ventilation treatment, while the second one (approximately 350 g per day) was observed by 24 days after fruiting. The wilted symptom started occurring by 22 days after fruiting under the natural-ventilation, whereas no incidence of the symptom was found under the forced-ventilation treatment. Interestingly, the forced-ventilation lowered the fruit growth rate (approximately 320 g per day) compared to the natural one. Maximization of the fruit growth rate under the forced-ventilation was found at 4 days later than that under the natural one. This result coincided with a slower plant growth under the forced-ventilation treatment. These results suggest that the forced-ventilation slows down extension growth of fruit and plant, which may be associated with lowering leaf temperature and saturation deficit. We suggest the hypothesis that the forced-ventilation may alleviate stress of the wilted symptom by avoiding extreme water evaporation from leaves due to high temperature and thus by reducing competition between leaves and fruits for water. More direct and detailed investigations are needed to confirm the effect of the forced ventilation.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.964-972
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• 2010

Objective of this research was to determine the influence of physico.chemical properties of root substrates on growth of daughter plants that were developed through plastic bag cultivation of mother plants in 'Seolhyang' strawberry propagation. Six different formulations of root substrates for daughter plant cultivation were peatmoss + vermiculite (5:5, A), peatmoss + perlite (7:3, B), coir dust + perlite (7:3, C), coir dust + peatmoss + perlite (3.5:3.5:3.0, D), rice-hull + coir dust + perlite (2:7:1, E), and rice hull + coir dust (3:7, F). The 10 cm plastic pots filled with formulated substrates were located near the plastic bag where mother plants were growing. Then the runners and daughter plants originated from mother plants were fixed on each root substrate filled into 10 cm plastic pot and daughter plants were grown in the plastic pots. The container capacity and air space showed big differences among substrates tested. The substrates E and F had the less container capacity and the higher air space than other substrates tested. This indicates that the two substrates would have difficulties in water managements during the raising of daughter plants. The substrates of A, B, and D which contained peatmoss in formulation had higher nitrogen concentrations than those containing coir dust or rice hull. The substrates of E and F which contained rice hull had lower nitrogen, phosphorus and potassium concentrations than those that contained coir. The crown diameters of daughter plants grown in substrate A were around 13 mm which is thicker than those grown in other substrates. The fresh weights of daughter plants grown in A substrate were the heaviest followed by C, F, D, E, and B. The dry weight of daughter plants showed similar tendency to those of fresh weight. The daughter plants which had heavy fresh and dry weights and thick crown diameter are considered good seedlings. Based on this justification, the substrates of A, C and F are acceptable for daughter plant growth of 'Seolhyang' strawberry.

• Economic and Environmental Geology
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• v.51 no.2
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• pp.185-201
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• 2018

Nuclear power plants(NPP) are constructed and operated to ensure safety against natural disasters and man-made disasters in all processes including site selection, site survey, design, construction, and operation. This paper will introduce a series of efforts conducted in Korea Hydro and Nuclear Power Co. Ltd., to assure the safety of nuclear power plant against earthquakes and other natural hazards. In particular, the present status of the earthquake, fault, and slope safety monitoring system for nuclear power plants is introduced. A earthquake observatory network for the NPP sites has been built up for nuclear safety and providing adequate seismic design standards for NPP sites by monitoring seismicity in and around NPPs since 1999. The Eupcheon Fault Monitoring System, composed of a strainmeter, seismometer, creepmeter, Global Positioning System, and groundwater meter, was installed to assess the safety of the Wolsung Nuclear Power Plant against earthquakes by monitoring the short- and long-term behavioral characteristics of the Eupcheon fault. Through the analysis of measured data, it was verified that the Eupcheon fault is a relatively stable fault that is not affected by earthquakes occurring around the southeastern part of the Korean peninsula. In addition, it was confirmed that the fault monitoring system could be very useful for seismic safety analysis and earthquake prediction study on the fault. K-SLOPE System for systematic slope monitoring was successfully developed for monitoring of the slope at nuclear power plants. Several kinds of monitoring devices including an inclinometer, tiltmeter, tension-wire, and precipitation gauge were installed on the NPP slope. A macro deformation analysis using terrestrial LiDAR (Light Detection And Ranging) was performed for overall slope deformation evaluation.