• Journal of the Korean Society for Heat Treatment
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• v.20 no.1
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• pp.22-30
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• 2007

Effects of ferrite grain size on static and dynamic deformation behaviors of SCM415 stels were investigated in this study. Dynamic torsional test was conducted using torsional Kolsky bar with the strain rate of $1.6{\times}10^3/s$. Specimens with three different grain size of ferrite, $4.6{\mu}m$, $11{\mu}m$, $35.5{\mu}m$ were used. Dimple fracture mode of the dynamic test specimens showed adiabatic shear bands on the beneath of fracture surface. Increased uniform elongation and decreased non-uniform elongation appeared as grain size of ferrite decreased in dynamic torsional test. However, shear strength was independent on grain size of ferrite.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.10
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• pp.1320-1326
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• 1999

Since it is not possible to generate spatially uniform particle distribution at low pressures in which in-situ particle monitors(ISPMs) are normally operated, it is of interest to investigate the response of an ISPM to particle beams at low pressures. The purpose of this study is to develop technique that can control the size of particle beams. In this study, particle beams were generated at low pressures by using identical aerodynamic lenses, and their shape and size were visualized by collecting uniform sized methylene blue aerosol particles on a filter media. It was found that the size of particle beams depends on the number of lens, the distance between lenses, and the downstream distance from the final lens. The size of particle beams decreases with increasing distance between lenses, and increases with increasing downstream distance from the final lens. The experimental results obtained in this work will be used to investigate performance of an ISPM at low pressures.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.12
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• pp.2376-2384
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• 1992

A theoretical analysis is carried out to predict the characteristics of transient ignition phenomena for the spherical fuel droplets cloud with non-uniform droplet size and number density distribution. Numerical calculations are performed for various cases depending on the combinations of the major parameters such as ambient temperature and initial distributions of droplet size and number density. The results of present study show that the ignition delay decreases for higher ambient temperature and smaller droplet size. Droplets cloud of hollow type with outer concentrated distribution ignites most rapidly.

• Journal of the Korean Society of Clothing and Textiles
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• v.46 no.5
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• pp.910-926
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• 2022

Suitability for the human body, freedom to move and thermal insulation are important design considerations in military clothing. This study investigates the performance and wearer-satisfaction of the functional inner winter uniform currently used in Korea; it is hoped that our data can inform the development of a future version. Interviews were conducted, in which the participants suggested various improvements. The uniforms were mainly worn for guard duty or as daily attire in cold weather. The participants chose how many layers to wear according to the current situation, rather than sticking to the layering recommended in the manual. Layering choices did not significantly affect combat efficiency but were found to affect wearers' comfort. Wearers' satisfaction was found to depend on the convenience of the clothing, whether it was in the appropriate size, freedom to move and thermal insulation. Also, this study suggests a problem with the current size system, as the analysis of size distribution, across all sizes, the range of current production is insufficient to cover the demand.

• Fire Science and Engineering
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• v.11 no.3
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• pp.15-23
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• 1997

In this study, the alumina for gas sensor was prepared by anodic oxidation. It was stable thermally and chemically, and pore diameter and pore distribution was uniform. And the shape of pore was cylinderical. The aluminum plate was carried out by the thermal oxidation, chemical polishing and electropolishing pretreatment. The pore diameter, pore size distribution, pore density and thickness of alumina was observed with the change of reaction temperature, electrolyte concentration and current density. As a results, It was able to use for carrier because alumina which was prepared by anodic oxidationhas uniform pore size distribution.

• Fashion & Textile Research Journal
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• v.11 no.5
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• pp.753-763
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• 2009

The purpose of this study was to investigate the wearing situation and satisfaction of school uniforms with the middle and high school boys and girls, who have been in uniforms for one or more years. The subjects for the survey were a total of 560 from the 2nd and the 3rd grade of the middle school, and the 1st and the 2nd grade of the high school. The survey was performed with the questionnaire of 60 questions; 36 questions related to the actual status, such as the purchase, size, repair, and design of a school uniform, and 24 questions related to satisfaction. The results were as follows; 1. Regarding the school uniform purchase, middle school students attached importance to famous brand, while high school students valued design above everything else. The students confused with the school uniform sizing systems were 82.1 % and 72.5 % in middle and high school students. 2. 43% of middle school students and 34% of high school students had experiences of repairing their school uniforms. Regarding the reason for repair, the size misfit was the highest. Boys preferred a single breasted boxy jacket with middle hip line length, and straight trousers, and girls preferred a fitted jacket of waist line length, and flare skirt of the knee line length. 3. School uniform satisfaction score showed that students were not satisfied with their school uniforms so much. Middle school students had significantly lower satisfaction about the design and psychological protection than high school students. Even though high school students showed lower satisfaction about the price and the care of school uniforms, there were no significant differences between them.

• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.103-113
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• 2020

The purpose of this study was to development a uniform shirt for high school boys aged 16-18 in the 7th Human Dimension Survey data of Size Korea. The upper body was analyzed to classify the upper body shape and to understand the characteristics of the body by type. Through this, we wanted to obtain the basic data necessary for the development of school uniform shirts. For data analysis, SPSS Ver. 26.0 program was used. In high school boys, there was no significant difference in height by age, but in width, thickness, length, circumference, shoulder slope, and weight, there were significant differences by age. The upper body types were categorized into four types: long shoulder skinny type, long upper body obese type, short shoulder normal type, and long shoulder normal type. Based on the size and body type data extracted from this study, it is thought that the development of uniform shirts with excellent fit should be realized through practical fashion development and construction of a size system.

• Journal of Korea Water Resources Association
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• v.37 no.5
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• pp.387-395
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• 2004

A computer model was proposed to simulate channel changes and bed material sorting of the meandering channels with different grain size in time and space simultaneously. The bed at the outside of the meandering channel with mixed sediments was scoured deeply and composed of coarser materials, and at the inside was aggradated and composed of finer materials. The sorting process started at the upstream inflection point and was finished at the downstream inflection point. At the natural with complicated boundaries and non-uniform grain sizes, the bed near the outside at the bend and narrow width was scoured deeper with coarse materials than in the channel with uniform grain sizes. The point bars showed lip at the inside near the bend and the bed materials were finer The bed at the outside near the bend and in the narrow width was scoured deeply with the coarser materials.

• Journal of Welding and Joining
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• v.12 no.1
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• pp.59-72
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• 1994

This paper presents an on-line quality monitoring and control method to obtain a uniform weld quality in gas metal arc welding (GMAW) processes. The geometrical parameters of the weld pool such as the top bead width and the penetration depth plus half back width are utilized to assess the integrity of the weld quality. Since a good quality weld is characterized by a relatively high depth-to-width ratio in its dimensions, the second geometrical parameter is regulated to a desired one. The monitoring variables are the surface temperatures measured at various points on the top surface of the weldment which are strongly related to the formation of the weld pool The relationship between the measured temperatures and the weld pool size is implemented on the multilayer perceptrons which are powerful for realization of complex mapping characteristics through training by samples. For on-line quality monitoring and control, it is prerequisite to estimate the weld pool sizes in the region of transient states. For this purpose, the time history of the surface temperatures is used as the input to the neural estimator. The control purpose is to obtain a uniform weld quality. In this research, the weld pool size is directly regulated to a desired one. The proposed controller is composed of a neural pool size estimator, a neural feedforward controller and a conventional feedback controller. The pool size estimator predicts the weld pool size under growing. The feedforward controller compensates for the nonlinear characteristics of the welding process. A series of simulation studies shows that the proposed control method improves the overall system response in the presence of changes in torch travel speed during GMA welding and guarantees the uniform weld quality.

• Journal of Powder Materials
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• v.10 no.5
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• pp.318-324
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• 2003

The nano-scale crystallite sizes of uranium oxide powders in simulated spent fuel were measured by the neutron diffraction line broadening method in order to analyze the sintering behavior of the dry process fuel. The mixed $UO_2$ and fission product powders were dry-milled in an attritor for 30, 60, and 120 min. The diffraction patterns of the powders were obtained by using the high resolution powder diffractometer in the HANARO research reactor. Diffraction line broadening due to crystallite size was measured using various techniques such as the Stokes' deconvolution, profile fitting methods using Cauchy function, Gaussian function, and Voigt function, and the Warren-Averbach method. The non-uniform strain, stacking fault and twin probability were measured using the information from the diffraction pattern. The realistic crystallite size could be obtained after separation of the contribution from the non-uniform strain, stacking fault and twin.