• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.1-6
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• 1987

This study was designed to evaluate the characteristics, land use and genesis of well adapted paddy soils. They were mostly classified as the Haplaquepts in the U.S.D.A soil taxonomy and as the Grey soils in the Japanese soil classification system. The proportion of these soils in the total acreage of paddy lands was thirty three percents. The fifty four percents in average of these soils were distributed on the local valley and fans on gentle slopes developed from granite, granite gneiss and shale parent materials. The rests were on the fluvio-marine deposits and alluvial deposits. The soils were characterized with prominant development of gleized horizons and clayey or fine loamy textured category. The available soil depth and the ground water level were relatively deep. The base saturation percent were high with weak acidic pH. The potential productivity of these soils was high.

• Journal of Sericultural and Entomological Science
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• v.28 no.2
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• pp.1-8
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• 1986

This study was conducted to bring light on inducing factors for non-sprouting occured in the mulberry field of Kyungpook Province in 1983. The results are as follws ; 1. In spring, winter buds were suddenly died during germination, necrosis appeared in pholem and cortex of non-sprouting stem and measles at the bottom of non-sprouting stem. 2. The depth of available of soil was more shallow in the non-sproutiong field than in healthy field. 3. There was no signifioant difference between the healthy field and non-sprouting field in siol PH, the content of organic matter, available phosphorous and exchangeble cations. 4. Available boron content in soil was significantly more in healthy field than in non-sprouting field. 5. Boron content in leaf and bark was significantly lower in the non-sproutiong tree than in the healthy tree. 6. The non-sprouting fields were completely controlled by the application of 6kg/10a borax. 7. Cold tolerance of the mulberry tree was higher in the mulberry tree with boron than in the mulberry tree without boron. 8. Mulberry tree in Kyungpook Province in 1983 may absorb water earlier compared with the average year because of high temperature at the end of March, 1983 and they had been damaged by frost injuary due to the lowest temperature (-6.4$^{\circ}C$) on the grass at the beginning of April 1983. As the above results, non-sprouting bud in the mulberry fields of Kyungpook Province in 1983 had been occured by low temperature and boron deficiency and boron deficiency of mulberry trees accelerared the frost injury.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.3
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• pp.111-118
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• 2004

An ocean buoy was deployed 10 km off Donghae city, Korea at a depth of 130 m to measure meteorological (air pressure, air temperature, wind speed, wind gust, wind direction, relative humidity) and oceanographic data (water properties and currents in the whole column) in real-time. The buoy recorded a maximum wind gust of 25 m/s (10 minutes' average speed of 20 m/s) and a minimum air pressure of 980 hPa when the eye of typhoon Maemi passed by near the Uljin city, Korea at 03:00 on 13 September 2003. The wave height reached maximum of 9 m with the significant wave height of 4 m at 04:00 (1 hour after the passage of Maemi). The currents measured near the surface reached up to about 100 cm/s at 13:00 (10 hours after the passage of Maemi). The mixed layer (high temperature and low salinity) thickness, which was accompanied by strong southward current, gradually increased from 20 m to 40 m during the 10 hours. A simple two layer model for the response to an impulsive alongshore wind over an uniformly sloping bottom developed by Csanady (1984) showed reasonable estimates of alongshore and offshore currents and interface displacement for the condition of typhoon Maemi at the buoy position (x=8.15 km) during the 10 hours.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.99-114
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• 2004

Mineralogical characteristics of fracture-filling minerals from deep borehole in the Yuseong area were studied for the radioactive waste disposal project. There are many fracture zones in the deep drill holes of the Yuseong granite, which was locally affected by the hydrothermal alteration. According to the results of hole rock analysis of drill core samples, $SiO_2$ contents are distinctly decreased, whereas $Al_2$$O_3$ and CaO contents and L.O.I. values are increased in the -90 m∼-130 m and -230 m∼-250 m zone, which is related to the formations of filling minerals. Fracture-filling minerals mainly consist of zeolite minerals (laumontite and heulandite), calcite, illite ($2M_1$ and 1Md polytypes), chlorite, epidote and kaolinite. The relative frequency of occurrence among the fracture-filling minerals is calcite zeolite mineral > illite > epidote chlorite kaolinite. Judging from the SEM observation and EPMA analysis, there is no systematic change in the texture and chemical composition of the fracture-filling minerals with depth. In the study area, low temperature hydrothermal alteration was overlapped with water-rock interactions for a long geological time through the fracture zone developed in the granite body. Therefore the further study on the origin and paragenesis of the fracture-filling minerals are required.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.311-316
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• 2010

This study was conducted to investigate the effect of anaerobic fermentation of wheat bran to prevent root-knot nematodes which are infected in plastic house due to over 10 years continuous cultivation of fruits and vegetables. Anaerobic fermentation treatment of wheat bran was done for 20 days by mixture of 2,000 kg fresh wheat bran per 10 are and soil with water in 30 cm soil depth. Chemical treatment of fosthiazate was done by mixture of 6 kg soil for 7 days. Both treatments show suppression of density of rootknot nematodes, especially in anaerobic fermentation treatment. Anaerobic fermentation treatment keeps the low level of root-knot nematode density until 90 days of cultivation and also showed good effect of melon growth. Related with death percentage of melon plant, anaerobic fermentation treatment shows only 3% and also large size of quality fruit but control 65%. Anaerobic fermentation treatment of wheat bran have proved to control the level of root-knot nematodes instead of synthetic chemicals for at least one cropping season and it showed good effect to fruit quality.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.592-599
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• 2002

Objective : The purpose of this study was to evaluate the effects of several light curing methods and several adhesives on the microleakage of composite resin restorations in primary teeth. Materials and methods : In 150 extracted human primary anterior teeth, O-shaped cavities were prepared in the labial surface ; the cavity diameter and depth were 1.6mm. The cavities were filled with light-activated composite resin, Compoglass. Four kinds of adhesives were used. Each filling materials were polymerized with three light cure methods. The restorations were polished using Sof-Lex discs(3M Co., USA). The samples were thermocycled 1,000 times between $5^{\circ}C$ and $55^{\circ}C$ with a 1-minute dwell time. Then, they were immersed in a 2% methylene blue solution(pH 7) for 12hours. Subsequently they were sectioned labio-lingually through the center of the restoration with a diamond saw at low speed with a water coolant, and evaluated by stereomicroscopy. Microleakage analyses were done, using scores from 0 to 4. Results : Results showed the least microleakage in Compoglass group(P<0.05). There were less microleakage in SBMP group among the adhesive groups, but no significant difference was observed(P>0.05). And there were no significant differences among the groups depending on curing methods(P>0.05).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.9-20
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• 1991

The characteristics of the unconsolidated sediment in Gwangyang bay was analyzed from the core samples. The porosity of the sediment showed irregular variation with respect to the sedimentation depth, which indicated that sediment weight-induced consolidation was not significant. Numerical analysis for the mechanical and hydraulic behavior of the unconsolidated sediment due to the tidal sea level change was processed. Because of the delayed excessive pore pressure change in the very low permeable mud medium, the magnitude of the excessive pore pressure for the duration of the minimum sea level exceeded the total stress from the sea water weight, which resulted in the negative (tensional) effective stress below the top surface. The in-situ effective stress, obtained by superposing the tensional effective stress on the solid weight-induced compressive stress, was remained to be tensile (quick-sand condition) near the top surface of the mud deposit. The occurrence of the quirk-sand condition provided a theoretical evidence for the insignificant consolidation and the irregular porosity variation of the sediment. When the sand is distributed on the top surface of the mud layer, the quick-sand condition occurred below the sandy mud layer and the downward movement of sand particles was facilitated.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.152-172
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• 1992

The ship sailing among waves are suffered the various wave loads that comes from its motion throughout its life. Because there are dynamic, the analysis of ship structure must be considered as the dynamic problem precisely. In the rationally-based design, the dynamic structural analysis is carried out using dynamic wave loads provided from the results of the ship mouton calculation as the rigid body. This method is based on the linear theory assumed low wave height and small amplitude of motion. But at the rough sea condition, high wave height, relatively ship's depth, is induced the large ship motion, so the ship section configulation below water line is rapidly changed at each time. This results in non-linear problem. Considering above situation in this paper, the strength analysis method is introduced for the hull glider among waves considering non-linear hydrodynamic forces. This paper considers that the overall or primary level of the ship structural dynamic loading and dynamic response provided from the non-linear wave forces, and bottom and bow flare impact forces estimated by momentum slamming theory, in which the ship is idealized as a hollow thin-walled box beam using thin-walled beam theory and the finite element method. This method is applied to 40,000 Ton Double-Skin Tanker and attention is paid to the influence of the response of ship speed, wave length and wave height compared with linear strip theory.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.13-18
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• 1995

This experiment was carried out to investigate occurrence ecology and control of soil-flakes in flood-direct seeded rice field. The occurrence of soil-flakes were inhibited in blue light of 450nm wave length and promoted in red light of 660nm wave length. The diatoms of Pinnularia spp. largely occurred in low fertilizer level and which much more increased when nitrogen was mixed with thinly soil depth. The diatoms of Pinnularia spp. were effectively controlled by carbamate and triazine herbicides when treated in pre-emergence of soil-flakes. Beside, triazine herbicides, simetryne, dimethametryn, prometryne 5g ai/10a showed high control effect in pre and post-emergence of soil-flakes. Expecially, In water-direct seeded rice pyrazosulfuron-methyl molinate simetryne 5.37% GR and dimepiperate bensulfuron dimethametryn 7.643% GR showed high control effect on the soil-flakes when treated at 10 days after seeding and didn't showed rice injury.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.6
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• pp.408-415
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• 2016

Small fishing ports and coastal structures installed in a relatively low sea water depth disturb the wave induced current and cause the collapse of equilibrium state of sediment transport. These structures creates diffracted waves and matter the concentration of waves to cause the beach erosion. In order to mitigate these eroding problems on the beach, many counter measurements were proposed such as detached breakwater, groin or headland; however, these methods interrupt the aesthetic view of sandy beach due to the exposed structures above the sea level and have difficulty of applying to those beaches with the good scenery. Furthermore, some of these methods create secondary environmental problems after the installations. To eliminate these problems, one of the countermeasures, artificial reefs have been selected and used worldwide to minimize the disturbance of the scenery and secondary effects on the environment. Meanwhile, it is important to set the design elements for installing the artificial reefs such as that of length, opening width, clearing distances from the shoreline and more. Nevertheless, there are no construction manuals or standards for designing the artificial reefs with these important design elements yet. In this study, different conditions of artificial reefs were used with various cases throughout hydraulic model test to precisely analyze the changes of waves and currents to propose the standards of design elements to install the artificial reefs.