• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.2
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• pp.59-62
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• 1992

Empirical criteria for wave breaking on the coastal slope are substantiated theoretically for complex-shape basins. The theory developed here is a generalization of Carrier-Greenspan theory for a plane beach. The place and role of the linear theory for the description of run-up problem is discussed. The height of run-up on the beach of the basins with a “parabolic” profile is calculated for originally monochromatic wave.

• Korean Journal of Poultry Science
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• v.14 no.2
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• pp.113-123
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• 1987

This study was carried out to investigate the effects of age of hen and oviposition time on egg weight, egg shell quality and e88 shape index in White Leghorn laying hens. The data were collected from 150 laying hens for about 4 months from September 1, 1986 to January 6, 1987. The results obtained from this study were summarized as follows; The percentage of the eggs produced before noon was decreased and that of the eggs produced after noon was increased as the hen gets older. Egg weight was increased rapidly to 270 days of age but after 270 days of age the rate of egg weight increase was slowly downed. The egg shell thickness became thinner and egg shell breaking strength was reduced and egg shape index was increased as the hen gets older. The egg weight was decreased as the oviposition time was proceeded and the regression coefficients of egg weight on oviposition time were -0.6788--0.4170, which means that the egg weight was decreased 0.4170-0.6788g per one hour delay of oviposition time. Egg shell thickness was increased 0. 0.00377-0.00643mm and egg shell breaking strength improved 0.0287-0.034kg/$\textrm{cm}^2$ per one hour delay of oviposition time. But it seems that there was no relationship between the oviposition time and the egg shape index.

• Advances in concrete construction
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• v.10 no.1
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• pp.61-69
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• 2020

This paper looks into how the shape of headed bars may influence the durability of reinforced concrete structures. Nowadays the only heads used in site works are cylindrical in shape. An alternative shape of head is studied in this piece of work. The new head reduces the concentration of stresses and so the appearance of cracks. In this work durability is studied based on both, first cracking and failure mode. An experimental campaign of 12 specimens and finite element modelling are described. The specimens were subjected to an accelerated corrosion process using an electrical current supply. Direct current was impressed on the specimens until breaking. Test results and the results obtained from numerical models are presented. Results are presented in term of comparison between the two shapes of heads studied. It was shown that the shape of the head has a significant influence on durability of reinforced concrete structures with headed reinforcing bars.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.405-416
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• 2005

The rubblization technique is breaking the aged concrete pavement slab into rubblized concrete aggregate, and use it as an base material at its original position, then builds overlay above the rubblized base. This method has been successively used in USA due to the advantage of good contructibility, cost-effectiveness as well as the capability of preventing of reflection cracks. However, constructibility and economic performance of rubblization on typical Korean concrete pavements needed to be investigate since to typical Korean concrete pavements have thick slab, as well include lean concrete subbase course. This stud explored optimum breaking depth and suggested minimum 10cm based on reflection crack simulation test. Also proper head shape and impact energy were investigated based on small breaking field tests. It was found that $127kg/cm^2$ of stress with 52.3% of head contact area are breaking requirement. Also, Multi-head type breaker suitable for Korean condition was designed and developed. This multi-head type breaker was designed to rubblize old concrete to the suggested optimum rubblized-depth and rubblized-concrete-aggregate size to prevent reflection crack and maintain high bearing capacity. This machine was used for the test of rubblization of old concrete pavement on a non-use old concrete and a in-serviced road. In these two tests, engineering properties of rubblized base and constructability and cost were investigated. In both tests, the old concrete rubblized to targeted size and depth, and high-level bearing capacity was achieved. Also, superior constructability and lower cost compared with traditional reconstruction was examined.

• Korean Journal of Plant Resources
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• v.29 no.3
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• pp.339-346
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• 2016

This study was carried out to develop an effective seed propagation method for Thalictrum rochebrunianum var. grandisepalum (H. Lev.) Nakai by analyzing seed dormancy types and germination characteristics. Seeds were collected between September to October at Gangwon province, and well-selected seeds were used while being dry-stored at 4±1℃. The seed size ranged 4.52 × 1.58 ㎜ and the weight of thousand seeds were 1,603.5 ± 0.02 ㎎. The moisture content was 7.2%. Seeds were achene type, and morphology characters showed an elliptical shape and rough texture, and light brown in color. Moist-chilling treatment was conducted for dormancy breaking because the seeds had an undeveloped embryo of liner type. The embryo had developed during a moist-chilling period, constantly, and fully developed in 10 weeks. Consequently, it seemed to be non-deep complex or intermediate complex type of morphophysiological dormancy, and embryo dormancy was broken by wet-chilling for 10 weeks. After 10 weeks of wet-chilling treatment, seed germination began. Germination percentage was higher in dark condition raher than light condition and recorded the maximum at 25℃ in the dark (16.3%). A pre-soaking treatment with a combined plant growth hormones promoted germination and shortened T₅₀. Specifically, seed germination of 84.5% was achieved by pre-soaking of seeds with a combined solution of 500 ㎎/L GA₃ and 10 ㎎/L kinetin for 24 h after a wet-chilling treatment for 10 weeks. Thus the effect of plant growth hormones coupled with chilling temperature on seed breaking dormancy provide asubsequent growth of seedlings for successful plantation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.4
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• pp.187-192
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• 2007

Impact on cylindrical surface caused by plunging breaking waves is investigated experimentally. The breaking waves are generated in a wave flume by decreasing the wave maker frequencies linearly and focusing the generated wave components at one specific location. The breaking wave packets are based on constant wave steepness spectrum. Three inclination angles of cylinder are applied to examine the effect of contact angle between cylinder and front surface of breaking waves. Also, the effect of cylinder diameter on pressure distribution and its peak value is investigated by adopting three cylinders with different diameters. The longitudinal location of cylinder is slightly moved in eight different points to find out a probable maximum value of impact pressure. The pressures and total force on cylinder surface are measured by piezo-electric pressure sensors and 3-components load cell with 30kHz sampling rate. The variation of peak impact pressures and forces is analyzed in terms of cylinder diameter, inclination angle and location. Also, the pressure distribution on cylindrical surface is examined. The cylinder location and surface position are more important parameters that govern the magnitude and shape of peak pressures, while the cylinder diameter and inclined angle are relatively insignificant. In a certain conditions, the impact phenomenon becomes very unstable which results in a large variation of measured valves in repeated runs.

• Journal of the Semiconductor & Display Technology
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• v.3 no.3
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• pp.27-29
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• 2004

The responses of hypothetical silicon nanotubes under torsion have been investigated using an atomistic simulation based on the Tersoff potential. A torque, proportional to the deformation within Hooke's law, resulted in the ribbon-like flattened shapes and eventually led to a breaking of hypothetical silicon nanotubes. Each shape change of hypothetical silicon nanotubes corresponded to an abrupt energy change and a singularity in the strain energy curve as a function of the external tangential force, torque, or twisted angle. The dynamics of silicon nanotubes under torsion can be modelled in the continuum elasticity theory.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.05a
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• pp.63-66
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• 2004

The responses of hypothetical silicon nanotubes under torsion have been investigated using an atomistic simulation based on the Tersoff potential. A torque, proportional to the deformation within Hooke's law, resulted in the ribbon-like flattened shapes and eventually led to a breaking of hypothetical silicon nanotubes. Each shape change of hypothetical silicon nanotubes corresponded to an abrupt energy change and a singularity in the strain energy curve as a function of the external tangential force, torque, or twisted angle. The dynamics of silicon nanotubes under torsion can be modelled in the continuum elasticity theory.

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.53-60
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• 2022

This study investigated correlations between egg quality indicators to identify external egg quality traits to predict internal egg quality using non-destructive and convenient measurements. Thirteen indicators, including Haugh unit, albumen height, eggshell breaking strength, eggshell thickness, eggshell color (CIE L^*, CIE a^*, CIE b^*), and reflectivity value, egg weight, egg length, egg width, shape index, and yolk color, were investigated. A total of 180 brown eggs were obtained from one 27-week-old flock of Hy-line brown-laying hens raised in a cage system. Correlations were evaluated using Pearson's correlation coefficient (r). The results showed strong correlations between Haugh unit and albumen height, eggshell color CIE L^* and reflectivity, egg weight and width, egg weight and length, eggshell color CIE L^* and CIE a^*, eggshell color CIE a^* and reflectivity, and shape index and egg length (P<0.001). Moderate correlations were observed between eggshell breaking strength and eggshell thickness, eggshell color CIE a^* and CIE b^*, and shape index and egg width (P<0.001). Eggshell color CIE L^* was correlated with eggshell breaking strength (P<0.01), and eggshell color CIE a^* was correlated with Haugh unit, albumen height (P<0.01), and eggshell breaking strength (P<0.001). The present study showed significant correlations between eggshell color and other quality indicators. Thus, this study suggests that eggshell colors based on reflectiveness and the CIE L^*a^*b^* value can be used to estimate the Haugh unit, albumen height, eggshell breaking strength, and thickness.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.643-648
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• 2010

Waterjet is a very useful technology for rock excavation because of low level noise and vibration during breaking rocks. To accurately predict the volume and shape excavated by the waterjet, it is important to understand waterjet fracture mechanisms. There have been various theoretical assumptions and approaches in the literature. In this study, waterjet mechanisms are classified into three standards: a mechanism scale, theoretical assumption for a target material, and jet phase. In addition, through a waterjet experimental study for weathered and intact granitic rocks, a fracture shape is observed and analyzed on comparison with the previous mechanisms. As a result, best waterjet mechanisms are selected to explain the fracture pattern of the granitic rocks.