• Composites Research
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• v.12 no.5
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• pp.12-22
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• 1999

Aluminum based metal matrix composites(MMCs) are well known for their high specific strength, stiffness and hardness. They are gaining further importance because of their high wear resistance. In this study wear behavior of $Al/Al_2O_3/C$ hybrid MMCs fabricated by squeeze infiltration method was characterized by the abrasive wear test under various sliding speeds at room and high temperature. Wear resistance of MMCs was improved due to the presence of reinforcements at high sliding speed. Especially wear resistance of carbon hybrid MMCs was superior to other materials because of its solid lubrication of carbon. The friction coefficient of MMCs was not affected by the sliding speed.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.148-154
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• 1999

This study was carried out to verify grinding performance of dental diamond bur and investigate the possibility of AE application in dentistry field. Workpieces were made of acryl and bovine respectively for the experiments in this study. Grinding test was conducted to get the data of grinding resistance and specific grinding energy of four different types of diamond bur by using tool dynamometer. AE signal was acquired to verify grinding process in the AE measuring system. Tool wear was observed to find parameters about grinding characteristics of diamond bur by means of SEM picture. It was found that the wear of dental diamond bur could be detected with polishing of grinding material, removal of adhesive parts, wear of particles neighboring cutting nose, loss of material and elevation of temperature. The wear of B, C, D type diamond bur is due to wear and fracture of grain size. Abnormal state can be found through the behavior of AE signal in the grinding working. As a result, it is expected that forecast of abnormal state is possible using AE equipments under real time process.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.7
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• pp.1055-1065
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• 2002

The specific objectives of the survey were as follows: 1) to survey the knit wear purchasing behavior of the women in their twentieth and thirtieth, 2) to investigate the popular design, color, pattern and material, 3) to analyze the difference of knit wear purchasing behavior and preference. The data was on the base of the results of 321 pcs survey reports. The analysis methods was Means, Percentage, Frequencies, t-test and One-way ANOVA. The results of this study were as follows: 1) Most women were purchasing knit wear for combination with having other clothes. They were satisfied for design, color, activity and quality, but not for size changing after washing, keeping problems and raising of pilling. They liked simple or classic design, mono or pastel color, and no or simple skip pattern, check pattern. 2) The Single women were more purchasing knit wear by impulse for soft and easy handling, combination with other clothes, meet fashion trend than married women. And the women in their twentieth were get more informations for knit wear from mess media and displayed shop than the women in their thirtieth.

• Journal of the Korean institute of surface engineering
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• v.47 no.1
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• pp.13-19
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• 2014

The various surface treated conditions of Fe-3.0%Ni-0.7%Cr-1.4%Mn-X steel such as as-received, ion nitriding, DLC coated, DLC coated after nitriding for 3 hrs and 6 hrs were investigated to evaluate the beneficial effect for plastic mold steel. Micro Vickers hardness tester was used to estimate nitriding depth from the hardness profile and to measure hardness on the surface. Elastic modulus and residual stress were measured by a nanoindentator. Scratch test and SP (small ball punch test) were utilized to assess the adhesive strength of DLC coating. The depth of nitriding layer was measured as $50{\mu}m$ for the condition of 3 hrs nitriding and $90{\mu}m$ for that of 6 hrs nitriding. Hardness, elastic modulus, residual stress of DLC coating were 20.37 GPa, 162.78 GPa and -1456 MPa respectively. Residual stress on the surface of DLC coating after nitriding could increase to -3914 MPa by introducing nitriding before DLC coating. During the 'Ball-On-Disc' test ${\gamma}^{\prime}$ particles pulled out from the surface of nitrized layer tend to enhance abrasive wear mode since the fraction of ${\gamma}^{\prime}$ (Fe4N) in ion-nitrized layer is known to increases with nitriding time. Thus the specific wear rate of the nitriding layer increased. Comparing with nitriding the specific wear rate in work piece disc as well as ball decreased prominently in DLC coating due to the remarkable reduction in friction coefficient.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.2
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• pp.254-266
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• 2005

The purpose of this study were to develop snow-board upper wear with improved functionality. The study consisted of figure out appropriate ease amount of snow-board upper wear and make products by applying it to pattern design. The results of this study were as follows : First, The results of examined the difference between naked body measurements of and basic wear. According to motion, chest circumference(4.7cm, 5.1%), back width(8.9cm, 20.7%), and waist back length(8.0cm, 18.3%) increased. Around the elbow the length increased by 4.4cm(21.9%) when it was bent 90 degrees, while it increased by 6.0cm(29.8%) when it was bent to the full(145 degree). Second, 3 snow-board upper wear were selected and evaluated their appearance, comforts, and functionality, and that of the biggest margin proved to be the best. Eases necessary for motion proved to be insufficient especially in neck, arm and wrist parts of upper clothing. Third, on the basis of the analysis of snow-board upper wear on market, 2 pieces of experimental snowboard upper wear were designed, produced, and evaluated the patterns of with different ease, and snowboard upper wear B for experiment was proved to be better, Fourth, Snowboard upper wear was produced and evaluated for experiment 2 by giving additional ease to specific parts. Therefore experiment 2 was presented pattern, ease, and size of snowboard upper wear for with snowboard upper wear with improved functionality.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.4 no.2
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• pp.31-37
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• 1995

This study is focused on the prediction of appropriate tool life by clarifying the correlation between progressive tool wear and AE signal. when rcutting SM45C by End mill in machining center. First of all, end mill have a problem that position of sensor sticking because it is revolution tool, but I think that it can be bained specific character according to sticking Sensor in the Vise. Consequently, the following results have been obtained; 1. Each cutting speed of feed rate over 0.1mm had a tendency to increase linearly according to the RMSAE 2. The level of AE signal at the same cutting area was more sensitive to depth of cut tharn the variation of feed rate 3. In the range of cutting duringqr about 75minqr atqr cutting speed 27m/min flankqr wear turns up aboutqr 0.21mm, aboutqr 0.29mm in the caseqr of about 65minqr at 33/min, qr hereby RMSAE increased rapidly at 0.2mm flank wear, also AE-HIT and CUM-CNTS.

• Journal of Power System Engineering
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• v.10 no.2
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• pp.93-98
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• 2006

Metal matrix composites(MMCs) reinforced with ceramic particulates are receiving increasing attention because their high specific strength, low coefficient of thermal expansion and excellent wear resistance. Especially, Al-based composites(AMCs) have been widely applied for the aerospace and automotive industries. Such composites are mainly fabricated by the cast, powder metallurgy and infiltration process. In this study, SiC particulate reinforced Al-based composites were fabricated by thermal spray process and their wear behavior were investigated. Composites with different spray parameter were fabricated by using flame spray apparatus. Microstructure and wear behavior of the composites were observed by scanning electron microscope(SEM) and electron probe micro-analysis(EPMA).

• Journal of the Korean Ceramic Society
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• v.31 no.5
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• pp.520-528
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• 1994

An investigation was carried out to understand the effect of the amount of free silicon on the tribological properties of Si-SiC. The specimens of dense Si-SiC composites with various amount of free silicon were fabricated in the temperature of 175$0^{\circ}C$ after molding under various pressure. Wear properties were measured by ball-on-plate wear tester under the constant weight of 4 Kgf at constant sliding speed of 500 mm/sec in water. As the result, the Rockwell hardness and fracture strength of Si-SiC composites remained nearly constant up to 16.62 vol% of free silicon in the Si-SiC microstructure. The Si-SiC composites containing the free silicon of 16.62 vol% was considered to be prominent in the tribological properties, which had the friction coefficient of 0.08 and the specific wear rate of 2.4$\times$10-8$\textrm{mm}^2$Kgf-1. The analysis of the wear surface indicated the complicated processes occuring on the surface such as fine polishing, abrasion, microfracture.

• International Journal of Railway
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• v.2 no.2
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• pp.43-49
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• 2009

Wear and rolling contact fatigue (RCF) defects are most important causes of rail damage, and often interaction competitive at present railway track. Head check is one of rolling contact fatigue (RCF) defects, and generally occurs in mild circular curves and transition curves that are set at both ends of sharp circular curves. Wear tends to limit the crack growth of head checks by removing the material from the RCF surface. In order to clarify the conditions of the occurrence and growth of head checks, the authors measured the interacting forces between wheels and rails and the angle of attack of wheelset, and carried out contact analyses using the actual profile data of wheels and rails. The effects of the lateral force, the contact geometry, and the wear rate at rail gauge comer on the formation of head checks were also analyzed by using the worn profiles of actual wheels and rails and the data obtained by a track inspection car. Some specific range of wear rate at the gauge comer was identified as having close relation with occurrence of head checks.

• Journal of the Korea Fashion and Costume Design Association
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• v.10 no.3
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• pp.37-46
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• 2008

The purposes of this article are segmenting consumers by brand attachment motives and discovering the differences among the segmented groups in relation to clothing involvement and clothing behavior (ready-to-wear satisfaction, brand loyalty, purchased items, and purchased places). The subjects of this study were male and female consumers, who were residents in Seoul, Korea. The data had been collected during May, 2007, and statistical analyses used for the study were factor analysis, cluster analysis, t-test, and chi-square test. The results showed that brand attachment motive is composed of two factors: brand personality/individuality expression and conformity/status improvement. Based on cluster analysis, there were two brand attachment motive groups: individuality expression and status improvement segments. T-test showed that brand attachment motive segments were significantly different in terms of clothing involvement and clothing behavior (ready-to-wear satisfaction, brand loyalty and purchased items). For example, the individuality expression group was more interested in clothing, was more satisfied with ready-to-wear clothing, had higher brand loyalty, and usually purchased casual wear. Meanwhile, the status improvement group had a higher perceived risk in clothing involvement, was less satisfied with ready-to-wear clothing, had a lower degree of brand loyalty, and preferred to purchase formal wear. The results implied that brand attachment motive is an important variable in market segmentation, in which specific marketing strategies should be implemented for each targeted consumers.