• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.4
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• pp.121-131
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• 2013

This study focused on the sediment reduction effects of VFS (vegetative filter strip) systems for the general characteristics of uplands in Korea. General conditions of upland fields were investigated through national scales of annual agricultural statistics. 7-15 % of slope with loam soil was the dominant types of uplands, and the hydrologic soil group feature usually belong to Type B. The common sizes of uplands were bigger than 0.1 ha and less than 0.2 ha, and 86.2 % of them account for less than 1.0 ha. With this information, 0.1 ha, 0.5 ha, and 1.0 ha of uplands with various shapes and 7-15 % of slopes were considered for the VFS system simulations. 20 mm, 40 mm, and 100 mm of daily precipitation were applied. As a result, the trapping efficiencies of VFS systems were obtained 37.4~100 % for 7 % slope and 18.1~98.0 % for 15 % slope of the less than 1.0ha of uplands. As rainfall increased, sediment loads also increased with slope and slope length increase. Also as size and slope of uplands and slope length increased with VFS length decrease, the trapping efficiency decreased for the same amount of rainfall. The optimum lengths of VFS systems for the givien upland conditions were suggested based on the modelling results with condition of VFS length less than 20 % of upland areas.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.75-75
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• 2012

This presentation will focus on computational materials research carried out across length scales. Examples will be presented that illustrate the way in which state-of-the-art quantum mechanical calculations and atomistic simulations can be applied to explain experimental data, design new structures, determine mechanisms, and enable new investigations. In particular, the presentation will present key findings from an integrated experimental and computational investigation of the tribological properties of polytetrafluoroethylene and its composites and predictions regarding the mechanical and tribological properties of inorganic nanostructured materials.

• Journal of The Korean Astronomical Society
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• v.15 no.1
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• pp.41-48
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• 1982

PDS was used to get the structure of two barred spiral galaxies NGC 1313 and NGC 1365. The result shows that NGC 1365 has both a deep spheroidal component and an exponential disk, but NGC 1313 has only an prominent exponential component. The luminosity profiles indicate that KGC 1313 is in type I and NGC 1365 belongs to type II. The length scales $({\alpha}^{-1})$ were derived from the exponential luminosity distributions as 1.64 kpc for NGC 1313 and 2.49kpc for KGC 1365.

• Journal of the Korean Physical Society
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• v.73 no.12
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• pp.1808-1813
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• 2018

I develop a transfer matrix algorithm for computing the geometric quantities of a square lattice polymer with nearest-neighbor interactions. The radius of gyration, the end-to-end distance, and the monomer-to-end distance were computed as functions of the temperature. The computation time scales as ${\lesssim}1.8^N$ with a chain length N, in contrast to the explicit enumeration where the scaling is ${\sim}2.7^N$. Various techniques for reducing memory requirements are implemented.

• Korean Journal of Ichthyology
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• v.5 no.1
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• pp.96-112
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• 1993

The morphological characteristics of chum salmon Oncorhynchus keta, masou salmon. Oncorhynchus masou and rainbow trout, Oncorhynchus mykiss in Korea were studied from 1989 to 1990. It was found that 13 factors of the female and 11 factors of the male in body form, number of pyloric ceaca and gill rakers has significant specific differences. There were some differences among species in the ratios of body depth, caudal peduncle depth, dorsal fin length and anal fin length to standard length (PBL), and snout length, eye diameter, upper jaw length, and cheek to head length. In the ratio of head length to fork length of the male, chum salmon showed the highest(24.7%) value and rainbow trout the lowest(21.6%). No difference was found in the female. It was proved that number of vertebrae, gill rakers, pyloric ceaca and lateral line scales were useful taxonomical characteristics of the salmon species. In particular, the ratio of eye diameter (ED) to head length (HL) appeared to be a new taxonomic criterion for the salmons in Korean waters.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.4_1
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• pp.97-106
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• 1992

Total length of stream networks and main stream length vary with topographic map scales, and the stream length of drainage basin on topographic map can be viewed as a fractal. Total length of stream network and main stream length are represented as only stream area ratio($R_a$) based on Horton's laws, thereafter the fractal dimensions of stream network and main stream length are derived as a simple function of stream length($R_L$) and stream area ratios($R_a$) respectively. The derived equations of fractal dimension are applied to Sansung basin in Kum River and compared with the equations already existed. The stream network appeared as space filling with fractal dimension near 2 as map scale increases, while main stream length shows near 1. The results of this study are expected to be helpful in the quantitative analysis of drainage network composition with map scale.

• Korea-Australia Rheology Journal
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• v.21 no.4
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• pp.235-244
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• 2009

Miscible polymer blends still have heterogeneity in their component chain concentration in the segmental length scale because of the chain connectivity (that results in the self-concentration of the segments of respective chains) as well as the dynamic fluctuation over various length scales. As a result, the blend components feel different dynamic environments to exhibit different temperature dependence in their segmental relaxation rates. This type of dynamic heterogeneity often results in a broad glass transition (sometimes seen as two separate transitions), a broad distribution of the local (segmental) relaxation modes, and the thermo-rheological complexity of this distribution. Furthermore, the dynamic heterogeneity also affects the global dynamics in the miscible blends if the component chains therein have a large dynamic asymmetry. Thus, the superficially simple miscible blends exhibit interesting dynamic behavior. This article gives a brief summary of the features of the segmental and global dynamics in those blends.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2237-2248
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• 1995

In incompressible flow which has multi-length scale, it has a very important effect which dependent variables are used for adaptive grid generation. Among many length scales in incompressible flow, the dependent variables used for the adaptive grid generation should be able to represent the feature of the concerned system. In this paper, by using vorticity and stream function, in addition to velocity components, the smoother and more stable grid generation is possible and these four flow properties represent each scale. The adaptive grid generation for a lid-driven cavity flow with $N_{re}$ =3200 using four flow properties such as velocity components, vorticity, stream function is performed, and the usefulness of using vorticity and stream function as the indicator for adaptive grid generation is shown.

• Journal of the Korea Concrete Institute
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• v.11 no.3
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• pp.47-57
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• 1999

The small-scale models have been utilized for the prediction of inelastic behavior of reinforced concrete structures for several decades. The parameters that affect the similitude between the model and prototype are various. Among them, the effect of bond between the model reinforcement and the model concrete is one of the most important factors. The study reported herein is addressed to verifying this similitude in bond behavior. The simple beams which have the lap splice at the midspan were made and flexural tests were performed under two-point loading. The length of lap splice are varied from 0.4ld through 0.7ld and up to 1.0ld where ld is the development length of the reinforcement. The selected scales are 1/1, 1/5, 1/10 and 1/12. Two prototype specimens and three models were tested in addition to the associated material tests and the test results are compared from the viewpoint of similitude.

• Korean Journal of Ichthyology
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• v.5 no.1
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• pp.85-95
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• 1993

Sexual dimorphism of the matured chum salmon, Onchorhynchus keta, have been studied based on biometrical measurements and osteological characters. Male chum salmon has an elongated and hooked upper jaw and canine-like teeth on the upper and lower jaw. The ratios of snout length (SnL) and upper jaw length (UJ) to head length of male were larger than those of the female, whereas eye diameter (ED) and postorbital part of head (CK) of the male were smaller than those of the female's. The ratios of body depth, caudal peduncle depth, anal fin length and adipose fin length to the standard length (PBL) of the male were also larger than those of the female. On sexual dimolrphism was detected in number of fin rays, gill rakers and pyloric ceaca, where as number of lateral line scales and caudal vertebrae of the female was larger than those of the male. Glossohyal and vomer bones has no sexual difference. The ratio of width to length of supraethmoid bone of the male was larger than that of the female. The ratio of frontal part to posterior part of parasphenoid bone of the male was smaller than that of the female.