• Journal of Mechanical Science and Technology
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• 제16권2호
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• pp.270-278
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• 2002

In order to reduce the exhaust emissions of a spark ignition engine, it is important not only to improve the catalyst conversion efficiency, but also to directly reduce the engine-out exhaust emissions during a cold starting of the engine and warm up periods. The purpose of this study is to evaluate feasibility of a glow plug for an early fuel evaporator. In order to promote atomization, gasoline is injected on the glow plug with room temperature(20$\^{C}$) and high temperature(250$\^{C}$). To analyze the spray behavior characteristics, a PMAS is used to measure the SMD and the dropsize distribution of an impinging spray and a free spray. Results show that the evaporation rate of the impinging spray on the high temperature surface of the glow plug was higher than that of the free spray on the room temperature surface.

• 대한기계학회논문집A
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• 제20권10호
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• pp.3152-3159
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• 1996

Previous works about the cylindrical shape elastic body which is under longitudinal temperature distribution mostly show the results of free expansion, therefore exact thermo-elastic analysis is needed. The object of this work is to analyze the thermo-elastic problem of the hollow cylinder when the cylinder is under longitudinal temperature distribution. In this paper, the analytical solution is found by using Galerkin vector, and it is compared by the results of FEM. For displacements of cylinder, analytical values are almost same as the results of FEM, but free expansion is not fit for analytical solution and the results of FEM. stresses from analytical solution and the results of FEM show good agreement also. but the results are different near the end boundary, since St. Venant principle is applied.

• Journal of the Korean Statistical Society
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• 제15권1호
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• pp.9-25
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• 1986

In this paper we propose a distribution-free rank test for ordered alternatives in a randomized block design and investigate the properties of the proposed test. The proposed test is an extension of the Page test to allow replications in each cell. Some asymptotic properties including ARE's are investigated. A small sample Monte Carlo study was performed to compare the powers of the test considered in this paper for small samples. The results show that our proposed test is robust and efficient in the case of equally-spaced treatment effects.

• Communications for Statistical Applications and Methods
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• 제3권1호
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• pp.73-85
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• 1996

In this paper, we consider the distribution-free confidence intervals for the reliability of the stress-strength model when the stress X and strength Y depend linearly on some explanatory variables z and w, respectively. We apply these confidence intervals to the Rocket-Motor data and compare the results to those of Guttman et al. (1988). Some simulation results show that the distribution-free confidence intervals have better performance for nonnormal errors compared to those of Guttman et al. (1988), which are designed for normal random variables in respect that the former yield the coverage levels closer to the nominal coverage level than the latter.

• 대한화학회지
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• 제20권4호
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• pp.251-259
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• 1976

고분자의 graft site 분포를 통계적 방법으로 구하고 그 이론치를 GPC를 사용한 실험에 의하여 증명하였다. 결과에 따르면 고분자의 metalation (Li+ion)은 통계이론에 따르고 anionic graft 반응결과는 homopolymer(side chain과 backbone 고분자) 및 graft site가 통계적으로 분포되어 있는 graft polymer로 구성되어 있다

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.883-887
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• 1998

Hydration is the main reason for the growth of the material properties. A exact parameter to control the chemical and physical process is not the time, but the degree of hydration. Therefore, it is reasonable that development all material properties should be formulated in terms of degree of hydration. Mathematical formulation of degree of hydration is based on combination of reaction rate functions. The effect of moisture conditions as well as temperature on the rate of reaction is considered in the degree of hydration model. This effect is subdivided into two contributions: water shortage and water distribution. The former is associated with the effect of on the progress of hydration. The water needed for progress of hydration do not exist and there is not enough space for the reaction products to form. The latter is associated with the effect of free capillary water distribution in the pore system. Physically absorption layer does not contribute to progress of hydration and only free water is available for further hydration.

• 산업진흥연구
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• 제1권2호
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• pp.129-136
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• 2016

South Korea and Mongolia are both the member countries of the World Trade Organization, but neither was the country with FTA. Nowadays, South Korea widely concludes the FTA with other countries, and the trade area has extended toward the neighboring continents and seas. Mongolia is a country with smallest economic entity but large in area and with abundant underground resources. And it's a main strategic zone of Eurasia. After the disintegration of the Soviet Union, Mongolia began to turn to market economy, and eagerly made effort to open and reform. With the expanse of trade and economy cooperation between South Korea and Mongolia, Mongolia started its sea road expanding. And the south Korea went to inland to get the necessary resources. Both of them feed its needs and obtain its profits.

• Industrial Engineering and Management Systems
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• 제9권2호
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• pp.165-177
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• 2010

This paper discusses a method for pricing the storage of inbound containers in a container yard. The pricing structure is characterized by a free-time-limit and a storage price for the storage time that extends beyond the free-time-limit. A cost model is developed from the viewpoint of a public terminal operator as well as a private terminal operator. Unlike a previous study on this issue, this study assumes that the retrieval times follow a discrete probability distribution, which is more realistic than the previous study. A solution procedure is suggested and illustrated by using numerical examples.

• Bulletin of the Korean Chemical Society
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• 제22권12호
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• pp.1375-1379
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• 2001

Monte Carlo simulations of hard-spheres confined in parallel hard walls have been carried out extensively at various densities and for various wall distances. The compressibility factors in the directions parallel and normal to the wall have been calculated from the radial free space distribution function (RFSDF) with the results showing that the compressibility factors normal to the wall are smaller than those in parallel direction and that a solid phase is formed in the direction normal to the wall while a fluid phase remains in the parallel direction. An order parameter is found to classify the phases whether a system (or a molecule) is in a fluid or a solid state. The compressibility factors of narrow wall are very small compared to those when the wall is put away. A plausible mechanism of the rise of sap in xylem vessel has been proposed.

• Structural Engineering and Mechanics
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• 제25권6호
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• pp.753-765
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• 2007

The response histories and distribution of dynamic interlaminar stresses in composite laminated plates under free vibration and thermal load is studied based on a thermoelastodynamic differential equations. The stacking sequence of the laminated plates may be arbitrary. The temperature change is considered as a linear function of coordinates in planes of each layer. The dynamic mode of displacements is considered as triangle series. The in-plane stresses are calculated by using geometric equations and generalized Hooke's law. The interlaminar stresses are evaluated by integrating the 3-D equations of equilibrium, and utilizing given boundary conditions and continuity conditions of stresses between layers. The response histories and distribution of interlaminar stress under thermal load are presented for various vibration modes and stacking sequence. The theoretical analyses and results are of certain significance in practical engineering application.