• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.21-32
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• 2023

Interrill erosion dominates in forest areas, and the erosion rate in surface-disturbed areas is significantly increased by the development and expansion of rill. In this study, soil erosion experiments using simulated rainfall and inflow were performed to understand the development and the micromorphological changes of rill on steep slopes. The characteristic factors of the micromorphology, such as the rill cross section, rill volume, rill density, rill order, and rill sharpness, were analyzed according to steepness and location (upper or lower) of slope. The head-cut of the simultaneous incised rills by rainfall simulation moved rapidly upslope, and the randomly developed rills expanded deeply and widely with their connection. The rill cross section evolved to downslope gradually increased. The rill volume occupied about 78 % of the sediment volume, confirming that the contribution of the sediment from the rill erosion is greater than that of the interrill erosion. Although the rate of increase in rill order slowed as the slope increased, the total length and density of the rill generally increased. As the slope increased from 15° to 20°, the bed incision of rills became larger than the sidewall expansion, and the rill sharpness increased by 1.6 times. The runoff coefficient on the lower slope decreased by 12.3 % than that on the upper slope. It was evaluated that the subsoil exposures and formation changes by the rill expansion increased the infiltration rate. Although the sediment accompanying the rills generally increased with slope increase, it was directly influenced by the hydraulic velocity of enhanced rill with the local convergence and expansion in the process of the rill evolution.

• Horticultural Science & Technology
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• v.30 no.3
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• pp.329-333
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• 2012

A new Asiatic hybrid lily 'Redsky' cultivar was selected from a cross between 'Vivaldi' cultivar with pale pink color flower as mother plant and 'Prato' with orange colored flower in 2000 year. The selected bulb line was propagated and cultivated for line nomenclature as 'Gonong-F-na-10'. The survey of the growth and flower characteristics of 'Gonong-F-na-10' were conducted from 2005 to 2007 on summer cropping system under structure in Highland Agriculture Research Center, NICS, RDA. After all 'Gonong-F-na-10' was named as 'Redsky'. The flowers of the 'Redsky' cultivar had not soft hair and fragrance, and had orange red (O-R N30D) colored petals with dark brown spots in center of flower. The stem color was dark pink and brown caused by anthocyanin pigment, the stigma and pollen colors were brown. Flowering direction was upward. The flowering date was July 7 so early flowering. The plant height was 97.2 cm so long, number of flowers was 4.9 ea, and length of flower bud was 9.3 cm. The bulb weight was about 34.8 g and its bulb size was about 14.8 cm in circumference. 'Redsky' cultivar was registered as a new variety with No. 3119 in Korea Seed and Variety Service on June of 2010.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.254-260
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• 1999

Meteor Burst Communication can provide effective and economical means of communication where long distance VHF NLOS data transmission is needed; often ranges more than 1000 km. It has been, however, so far considered unsuitable for short distance application because of phenomenal decrease in burst durations, which leads to decreation of total duty rate of the system. This paper extensively analyzes characteristics of shot distance MB(Meteor Burst) path and shows the low duty rate may be improved by increasing burst rate through adapting antenna beam width to cover entire hot-spot region in the space and, by compensating effective burst length through cutting down man-made noises introduced by antenna. Based on the analysis, we are developed a small-opening-cavity antenna, especially designed for short distance MB path. In operation, the antenna is to be buried under ground surface so as to improve directivity and reduces noise introduction. The antenna exhibits power gain of 3 dB with 90 degree beam width and thus enables to illuminate entire hot-spot regions with the elevation angle of 8-90 degree which is the case of transmission less than 100 km. Directivity horizontal to earth surface is suppressed to minimum which enables to cut man-made noises from near-by sources down to more than 3 dB from the level reported with conventional 4 element Yagi. A series of experiments performed on 100 km MB paths have conformed that, with the antenna installed at receiving site, the burst rate and duration time have been noticed to increase by 10 and 20 percent respectively from the values obtained by conventional 4-element Yagi antenna under same testing condition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.6
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• pp.788-801
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• 1998

Meteor Burst Communication can provide effective and economical means of communication where long distance VHF NLOS data transmission is needed ; often ranges more than 1000 km. It has been, however, so far considered unsuitable for short distance application because of phenomenal decrease in burst durations, which leads to decreation of total duty rate of the system. This paper extensively analyzes characteristics of shot distance MB(Meteor Burst) path and shows the low duty rate may be improved by increasing burst rate through adapting antennal beam width to cover entire hot-spot region in the space and, by compensating effective burst length throughcutting down man-made noises introduced by antennal. Based on the analysis, we are developed a small-opening-cavity antennal, especially designed for short distance MB path. In operation, the antenna is to be buried under ground surface so as to improve directivity and reduces noise introduction. The antennal exhibits power gain of 3 dB with 90 degree beam width and thus enables to illuminate entire hot-spot regions with the elevation angle of 8-90 degree which is the case of transmission less than 100 km. Directivity horizontal to earth surface is suppressed to minimum which enables to cut man-made noises from near-by sources down to more than 3 dB from the level reported with conventional 4 element Yagi. A series of experiments performed on 100km MB paths have conformed that, with the antenna installed at receiving site, the burst rate and duration time have been noticed to increase by 10 and 20 percent respectively from the values obtained by conventional 4-element Yagi antennal under same testing condition.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.121-132
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• 2009

Thin bonded continuously reinforced concrete overlay(CRCO) was constructed on He existing jointed plain concrete pavement(HCP) surface at Seo-Hae-Ahn express highway in South Korea in order to evaluate its applicability and performance. Two sections of road were considered for this evaluation. In the first section, the concrete overlayer was placed and cut down to the existing layer to form transverse joints while CRCO was constructed on top of the existing layer in the second section. Early strength concrete(Type III) was utilized for both overlay sections. The depth of milling and the thickness of overlaid layer were 5 cm and 10 cm, respectively. Several vibrating wire gauges(VWG) were installed to evaluate the performance of CRCO with respect to curling, delamination, and crack propagation. As a result of the strength test, it was found that strength of the material reaches the design criteria within 1-3 days. Analysis with vibrating wire gauge(VWG) showed CRCO effectively restricts joint movement. High adhesive strength also was observed from the material regardless of length of aging. Meanwhile, transverse cracks were observed on the middle of the section where JPCP overlay was applied whereas arbitrarily cracks in transverse direction were observed on the section where CRCP was applied.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.2
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• pp.86-91
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• 2008

Ships operating in littoral sea are likely to be subjected to accidental load such as stranding. Once she has damage on the hull structure, her ultimate strength will be reduced. This paper is to investigate the effect of the stranding damage on ultimate strength of ship structure by using a series of collapse tests. For the experiment, 720 mm $\times$720 mm in section and 900mm in length of five box-girder models with stiffeners were pre- pared. Of the five, one has no damage and faur have an diamond shaped damage which represents the shape of rock section in seabed. The damage size is different between models. Among the damaged models, the damages of 3 of them were made by cutting the plate and one by pressing to represent stranding damage. Experiments were carried out under pure bending load and the applied load and displacements were recorded. The ultimate strength is reduced as the damage size increases, as expected. The largest damaged model has the damage size of 30% of breadth and its ultimate strength is reduced by 21% than that of no damaged one. The pressed one has lower ultimate strength than cut one. This might be due to the fact that the plate around the pressed damage area effect negatively on the ultimate strength.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.1
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• pp.25-34
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• 1976

The purpose of the present study on the radula of Korean marine gastropods is to determine the systematic position of the species by the radula features. The radula features of 9 Families based on the observation of specimens consisting of 31 species are described briefly as follows. 1. Naticidae; Radula formula 2-1-C-1-2. Rachidian is 3-cusped. All cusps are strong and pointed. The lateral tooth is massive and strong with a huge triangula cusp. Two marginal teethare slender, long and strong. 2. Cymatidae; Radula formula 2-1-c-1-2. Fachidian, 1-cusped. Cusp is strong and acute. The basal margin is toothed with a number of small denticles. The lateral tooth is beak-like and strong with groove inside. The marginal teeth are slender and pointed. 3. Tonnidae; Radula Formula 2-1-C-1-2. Rachidian, 3 cusped. Central cusp is huge, strong and abruptly pointed. Lateral cusp is blunt and relatively small. The lateral tooth and maginal teeth are identical to that of the preceding one. 4. Muricidae; Radula formula 1-C-1. Rachidian has 3 to 5 cusps. Central cusp, long, thick, strong and pointed. Lateral cusps are rather shorter than central, thick, strong and well cut with several minute denticles along outer margin. The lateral tooth is falciform. 5. Pyrenidae; Radula formula 1-c-1 Rachidian lacks of cusp. The base is thin, narrow, small and rectangular. Lateral tooth has 2 cusps with a crescent shaped base. 6. Buccinidae; Radula formula 1-C-1. Rachidian has 3 to 7 cusps. The base is massive and broadened laterally. The lateral tooth is large-and has 2 to 4 cusps. The central cusp is the shortest, and become longer towards the each side. 7. Busyconidae ; Radula formula 1-C-1. Rachidian, 3-cusped with a massive base. All cusps are pointed and strong. Centeral cusp is rather shorter than lateral one. Lateral tooth, 2-cusped. Inner cusp short about one half the length of outer one. 8. Fasciolariidae; Radula formula 1-C-1. Rachidian, 3 to 4-cusped. Very small in size. Lateral tooth broadened laterally with about 10 thin, long, sharp cusps. 9. Volutidae ; Only the rachidian exists. Rachidian, 3-cusped. All cusps are strong and sharply pointed. Central cusp is narrower than lateral ones. Anterior basal margin is concave.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.4
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• pp.1-9
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• 1982

Variation of soil properties is studied by permeating injection of chemical grouts, such as cement type, water-glass type and acrylamide type, to the same soil samples with different densities. Moreover, injection tests using specially prepared equipments of 1.0 shot system and 1. 5 shot system are attempted to investigate permeating injection effects in highly compacted soil and in the presence of ground water. The main factor which causes the improvement of cut-off effect and shearing strength is the cohesion of soil. The strength in the loose state is fundamentally governed by the membrane cohesion, meanwhile, in the loose state is governed by the structural cohesion. Injection effects under the ground water flow is considerably decreased, and effective gelling ratio of approximate 45~80% is observed by variation of velocity and gel time, besides grading of injection materials has high relation with permeation and traveling length but has little relation with effective gelling ratio. Permeating injection effects, such as gelling scope, gelling strength in highly compaoted soil conditions can be confirmed by penetration resistance diagram and iso-strength curve.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.705-711
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• 1999

Post-mortem pork loins were used to investigate the effects of gamma irradiation on the surface and inside color, heme pigments, muscle protein solubility, purge loss, electrophoretical patterns of muscle proteins, and tenderness. The muscle was cut into pieces of 5 cm in length and divided into both groups, vacuum-packaged and air-packaged. The packaged samples were irradiated at designed doses, 0, 1, 3, 5 and 10 kGy, by a cobalt-60 irradiator, and stored at $4^{\circ}C$ for 7 days. There were no significant differences in the purge loss and electrophoretic patterns. Hunter's L and a values of the surface and inside of loins increased by gamma irradiation, showing a bright red color and the red color was maintained during the storage of both samples. However, the concentrations of heme pigments were not significantly changed. Muscle protein solubility slightly increased by increasing the applied dose. The decrease in shear force was observed in irradiated samples. As result, it was expected that meat quality, especially color and processing properties, could be improved by gamma irradiation at below 5 kGy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.382-389
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• 2019

A novel folding process is proposed using a repeated cold-die forging and annealing to form a sterling silver ring. Sterling silver plate was cut into a doughnut shape, and lattices with 0.43-mm line-width were imprinted on it. The sample was folded by forging using dies with slopes of $45^{\circ}$, $60^{\circ}$, and $75^{\circ}$ and annealing. For comparison, samples were also fabricated without annealing. Strain was identified by measuring the length of lattices. Vernier calipers, a Vickers hardness tester, an optical microscope, and a UV-VIS colorimeter were used to determine the size, hardness, microstructure, and body color. Without annealing, cracks occurred. However, successful deformation was possible when annealing was used. The results of macro strain measurements show that the outer diameter and width decreased, while the inner diameter and thickness increased after the final process. The maximum strain was increased 0.128 toward the parallel direction. The Vickers hardness decreased after annealing and increased after the folding process. The microstructure results showed that the grain size increased after annealing but decreased after folding. The color difference based on the Lab index was under 10 for all processes. Eventually, a doughnut-shaped silver plate was successfully deformed into a ring shape by the folding process.