• Structural Engineering and Mechanics
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• 제75권5호
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• pp.621-631
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• 2020

A laboratory experiment is conducted is to investigate the behaviour of a low-mass-ratio and high aspect ratio flexible cylinder under vortex-induced vibration (VIV). A flexible cylinder with aspect ratio of 100 and mass ratio of 1.17 is towed horizontally to generate uniform flow profile. The range of Reynolds number is from 1380 to 13800. Vibration amplitude, in-line and cross-flow frequency response, amplitude trajectory, mean tension variation and hydrodynamic force coefficients are analyzed based on the measurement from strain gauges, load cell and CCD camera. Experimental results indicate that broad-banded lock-in region is found for the cylinder with a small Strouhal number. The frequency switches in the present study indicates the change of the VIV phenomenon. The hydrodynamic force responses provide more understanding on the VIV of a low mass ratio cylinder.

• 아동학회지
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• 제15권1호
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• pp.55-69
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• 1994

The purpose of this study was to investigate methodological and theoretical problems in measuring the acquisition of national identity of in-country and over-seas Korean adolescents. The subjects consisted of 574 incountry and overseas (Chinese, Russia and Japan) Korean adolescents (total 509), 15 to 25 years of age. Data were collected with the use of a questionaire, the Scale of National Identity. The results were that (1) the concept of national identity was organized on two dimensions (cognitive vs. sociocultural). The former consisted of 6 cognitive characteristics (uniqueness, sameness, continuity, acceptability, respectability and royalty). The sociocultural dimension consisted of the cognition of 7 sociocultural characteristics (history, norm, fraternity, symbol, consanguinity, Korean language and nationality). Except for consanguinity, there was a close relationship within each and between the 6 cognitive characteristics. Also there was a close relationship within each and between the 7 sociocultural characteristics of national identity. (2) Some demographic variables, such as age of respondents, place of birth and level of understanding of Korean language contributed to acquisition of national identity. (3) Among several demographic variables, nationality was the most explainable.

• 복식
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• 제65권4호
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• pp.31-44
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• 2015

The purpose of this study is to examine introduction and establishment of the police uniform during Japan's early Meiji period, in order to get deeper understanding of the introduction of the modern uniform. The research method included a literature review of laws related to police uniform, which were collected and analyzed. The result shows that the uniform stipulated by Keisi-cho Uniform regulation in 1874 included characteristics of Western uniforms that show the rank of the officers using emblems, such as different cap badges and uniform stripes, while maintaining the same form. Later, the modern uniform system came into form with the addition of a national symbol, building system of formal wear, separating uniforms for different classes, and adding additional uniforms. This illustrates the process of introducing and establishing western-style uniform in the East and can serve as a reference for similar studies.

• 한국환경과학회지
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• 제1권1호
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• pp.45-50
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• 1992

Understanding the nonlinear flow caused by orographic effects can be valuable in siting of new businesses, industries, and transportation facilities. In spite of recent work on large-amplitude waves and wave breaking, the studies of flow around large scale mountains have just begun. The generative mechanism of lee vortices in the lee of large scale mountain Is investigated by Ertel's theorem. The CSU RAMS is used as a numerical model. According to the numerical results, the isentropes are depressed behind the large scale mountains. This means the vortex lines must run upward and downward along the depression surface because vortex lines adhere to isentropic surfaces. Therefore, the vertically oriented vorticity can be formed in the lee of the large scale mountain. This vorticity plays an important role for orographic Precipitation, because strong vertical velocity and cloud bandy are developed along isothermal deformation surface.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1742-1756
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• 2023

The hydrogen behavior in a nuclear containment vessel is a significant issue when discussing the potential of hydrogen combustion during a severe accident. After the Fukushima-Daiichi accident in Japan, we have investigated in-depth the hydrogen transport mechanisms by utilizing experimental and numerical approaches. Computational fluid dynamics is a powerful tool for better understanding the transport behavior of gas mixtures, including hydrogen. This paper describes a Large-eddy simulation of gas mixing driven by a high-buoyancy flow. We focused on the interaction behavior of heat and mass transfers driven by the horizontal high-buoyant flow during density stratification. For validation, the experimental data of the Containment InteGral effects Measurement Apparatus (CIGMA) facility were used. With a high-power heater for the gas-injection line in the CIGMA facility, a high-temperature flow of approximately 390 ℃ was injected into the test vessel. By using the CIGMA facility, we can extend the experimental data to the high-temperature region. The phenomenological discussion in this paper helps understand the heat and mass transfer induced by the high-buoyancy flow in the containment vessel during a severe accident.

• Advanced Composite Materials
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• 제16권1호
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• pp.31-44
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• 2007

The purpose of this study is to improve the examining and understanding of the bonding behavior of Fiber Reinforced Polymer (FRP) sheets bonded to concrete blocks and steel plates under fatigue loading. First, a series of experimental investigations is summarized in the paper. The fatigue behavior of bonding surface between FRP sheets and concrete is finally characterized by the conducted P-S-N diagram representing the relationship among the probability of FRP debonding (P), the bond stress amplitudes (S), and the number of cycles (N) at debonding on a semi-logarithmic scale. The different debonding modes for various fracturing surface are also investigated and evaluated.

• International Journal of Aeronautical and Space Sciences
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• 제10권1호
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• pp.20-29
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• 2009

There are concerns about the influence of the gust wind caused by helicopters affecting the moving vehicles while hovering over the road during rescue activities. For the understanding of such complicated flow. numerical simulation of a rotor hovering above the ground has been carried out, changing the rotor/ground clearances. The rotor thrust is kept constant. and the rotor control is determined by trim adjustments incorporated into the CFD algorithm. Collective pitch angle and the required power decreases with the rotor/ground clearance which agrees with experience. Changes of the flowfield near the rotor with regard to the rotor height are investigated based on the calculated results.

• 농촌계획
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• 제16권3호
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• pp.51-66
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• 2010

This paper performed a basic study for the development of so called a Korean style community garden, a Kleingarten in Japan, according to the increase of demand for green tourism For this, theoretical research and interviews with site surveys for Kleingarten in Japan were carried out and some strategic conclusions were drawn. The results show that, from the perspective of hardware, facilities and size should be setup according to the condition in Korea and long-tenn demands for green tourism Adequate size of lodging facility, a cottage, should accompany the garden. More attention should be paid for the management of Kleingarten. In addition, from the perspective of software, Administration should make an effort to obtain the understanding and cooperation from the local residents. It turns out that a Kleingarten takes an important role when urban residents move into rural areas or carry out a multi-habitation. Barrier-free design for cottages is also needed.

• 한국의상디자인학회지
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• 제12권2호
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• pp.107-118
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• 2010

The purpose of this study is to be data and to help understanding of pattern of Korean, Chinese and Japanese traditional dress. The methods of this study are the study of academic literatures as well as practical study through the analysis of case studies about actual works. The summary of this study's results is like followings. First, standard of Pattern are nature, mam-made in motif object, Naturalistic, Geometric, Stylized, Abstract in motif express, Order, Disorder in pattern express. Second, a point of sameness of motif object in traditional dress of three nations were that nature and letter abstractive of mam-made is a lot. but motif of Japan was used in daily life motif of mam-made which was not in Korea and China Third, commonly, motif expression of three nations were developed Naturalistic, Stylized. but in Naturalistic, Korea was simple, plane, China was three-dimensional, Japan was expressed super realism. Fourth, as formative aesthetic of Pattern, Korea is natural, plane, simple and symbolic, China is gorgeous, three-dimensional, immaculacy, filling and symbolic, Japan is delicate, complicated, decoration and symbolic.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.124-133
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• 2004

Global climate variations are expected to affect local hydro-meteorological variables like precipitation and temperature. The Southern Oscillation (SO) is one of the major driving forces that give impact on regional and local climatic variation. The relationships between SO and local climate variation are, however, characterized by strong nonlinear variation patterns. In this paper, the nonlinear dynamic relationship between the Southern Oscillation Index (SOI), precipitation, and temperature in Fukuoka, Japan, is investigated using by a nonlinear multivariable approach. This approach is based on the joint variation of these variables in the phase space. The joint phase-space variation of SOI, precipitation, and temperature is studied with the primary objective to obtain a better understanding of the dynamical evolution of local hydro-meteorological variables affected by global atmospheric-oceanic phenomena.