• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.97-98
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• 2009

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.994-999
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• 2011

The main wearing slider of pantograph is a difference which is considerable to wear phenomenon according to material properties. Especially, Cu-type wearing slider suddenly occurs the abnormal wear by precipitation, this threatens the travelling safety of the train. The abnormal wear by precipitation and arc influences are main factor decided to life time of Cu-type wearing slider and contact wire. Consequently, the application of the main wearing slider with wear resisting capacity, electrical conductivity, resistance arc and lubrication is demanded. In this paper through tribologic approach, overcame abnormal phenomenon of the Cu-type wearing slider by the precipitation and for the economic efficient augmentation by durability improvement and the travelling safety were accomplished. The Cu-type wearing slider which has excellent electric conductivity and arc characteristic but it occurs the normal and abnormal wear phenomenon according the precipitation which changes, respectively. Consequently, this phenomenon grasps fixed quantity according to precipitation, a mileage and wear volume then Fe-type wearing slider compared and analyzed.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.77-82
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• 1998

The Part of slot on rotary compressor which plays an important part of the reliability and performance is studied on machinability and the wear characteristics for the specimen made by sand mold and permanent mold. The experiment are used the face cutter of milling machine which make the processing surface like broaching process and rollblock wear test machine. Permanent-mold casting iron is not affected by variation of RPM of milling machine, but sand-mold cast-iron is improved to increasing RPM. Also sand-mold casting iron shows superior wear characteristic to permanent-mold casting iron. This results from harder matrix of pearlite structure and self-lubrication characteristics of graphite. And wear particles in tested oil show shape and size similar to severe wear particles of oil taken from rotary compressor. The material and surface condition of slot play important part of the reliability and performance.

• Tribology and Lubricants
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• 제25권3호
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• pp.192-196
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• 2009

This paper presents the hardness and wear characteristic of bronze metals, which are manufactured by a sintering process with a high pressuring technology. A bronze metal with a high hardness and anti-wear properties is usually used for a high pressure cylinder and a pin-bush bearing. The new bronze metal in which is manufactured for this experimental study shows very high hardness of 192${\sim}$220 Hv compared with that of a conventional bronze metal of 120${\sim}$140 Hv. The high hardness of new bronze metals is strongly related to the radical reduction of wear volumes and an improved surface roughness of operated worn surfaces. As explained by previous many research works, the improved hardness of nonferrous metals may increase a load-carrying capacity and anti-wear properties of tribological components.

• 한국기계가공학회지
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• 제10권2호
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• pp.117-123
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• 2011

The purpose of this study is to show the friction and wear characteristics on the vapor deposited coating layers on the SCM415 steel. In this research, frictional wear characteristic of coating materials such as Ti-series, Cr-series & WC/C and TiAlN+WC/C multilayer coating was investigated under room temperature, normal air pressure and no lubricating condition. Therefore, this study carried out research on the friction coefficient, micro hardness(Hv), surface roughness and wear quantity on the vapor deposited coating layers on the SCM415 steel. As the wear experimental result, the excellence of TiAlN+WC/C multilayer coating has been proven by high micro-hardness, low friction coefficient and wear quantity.

• 한국정밀공학회지
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• 제12권5호
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• pp.98-107
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• 1995

The in-process detection of drill wear and breakage is one of the most importnat technical problems in unmaned machining system. In this paper, the monitoring system is developed to monitor abnormal drilling states such as drill breakage, drill wear and unstable cutting using motor current. Drill breakage is detected by level monitoring. Tool wear is classified by fuzzy pattern recognition. The key feature for classification of tool wear is the estimated flank wear which is calculated by the proposed flank wear model. The characteristic of the model is not sensitive to the variation of cutting conditions but is sensitive to drill wear state. Unstable cutting states due to the unsmooth chip disposal and the overload are monitored by the variance/mean ratio of spindle motor current. Variance/mean ratio also includes the information about the prediction of drill wear and drill breakage. The evaluation experiments have shown that the developed system works very well.

• 품질경영학회지
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• 제20권1호
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• pp.59-67
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• 1992

This paper deals with preventive replacements models for the item whose failures are dependent on their wear level. When measuring the item wear level is very costly, it may be economical to use substitutive characteristics that are correlated with the item wear level and relatively inexpensive to measure. In this paper, replacement policies based on such substitutive characteristics are proposed. The optimal level of substitutive characteristic to replace the item, which minimizes total cost, is obtained. Some numerical examples are also given.

• 한국표면공학회지
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• 제42권6호
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• pp.272-275
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• 2009

The purpose of this study is to show the friction and wear characteristic behaviors of TiN and CrN coated SKD61 which is applied to Al 6xxx extrusion mold material. The friction and wear characteristic behaviors of both coating layers were investigated by the reciprocating friction wear tester under atmospheric pressure and un-lubricated state. The processing parameters in this study were temperature (50 and $120^{\circ}C$) and load (3, 5, and 11 kgf). This study was carried out while comparing the coefficient of friction and microstructure of TiN and CrN coating layers on SKD61. The coefficient of friction of CrN became lower than that of TiN at all conditions. Therefore, CrN was suggested to be more advantageous than TiN for extrusion mold.

• 한국정밀공학회지
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• 제13권11호
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• pp.25-31
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• 1996

In this paper, three different types of commercial tools -P20, NC123K and ceramic- have been used to cut austempered ductile iron(ADI). In the austempered condition the materials are hard, strong and difficult to machine. Thus, we selected a optimum tool material among three different types of used tools in machining of austempered ductile iron. It was used acoustic emission (AE) to know cutting characteristic for selected tool and investigate characteristic of AE signal according to cutting condition and relationship between AE signal and flank wear land of the ceramic tool. The obtained results are as follows ; (1) The ceramic tool among three different types of tools is the best in machining austempered ductile iron. (2) In case of ceramic tool, the amplitude level of AE signal(AErms) is mainly affected by cutting condition and it is proportional to cutting speed. (3)There have been the relationship of direct proportion between the amplitude level of AE signal and flank wear land of the tool. (4) It was observed that the value of AErms was only affected by cutting speed. Therefore it is possible to in-process detec- tion of ceraic tool's wear in case the initial value of AErms at each cutting speed decided.

• 패션비즈니스
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• 제9권5호
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• pp.1-14
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• 2005

The purpose of this study was to analysis the perception of men's wear brands (Intermezzo and Rogatis), for developing the possibility & strategy of the nichi-market in men's wear market for the apparel marketers and manufactures. For this study, the data obtained from 312 respondents were analyzed by descriptive statistics, ANOVA. The results from the study were as follow ; The perception of the 2 brand images revealed that Intermezzo accounted for 79.8% of the frequencies, and Rogatis accounted for 99%. Also, results revealed the total evaluation of Intermezzo accounted for 3.86 of the mean rated on 5 point Likert-type scales in the 9 features, and Rogatis accounted for 3.28. And then, results revealed that there were signifiant differences in 2 cluster of Rogatis that the purchasing cluster accounted for 3.46 of the mean, and the perceiving cluster accounted for 3.07. The brand images of Intermezzo and Rogatis were evaluated and rated on 5 point Likert-type scales of 17 pair adjectives. As a results, the image characteristic with Intermezzo was considered with more dynamic, trendy than the image characteristic with Rogatis. Also, results revealed that The Image with Intermezzo was considered with urban, lively, chic, modern, and sophsticated image-features, and the Image with Rogatis were evaluated mannish, urban, sophsticated, luxury, and static image-features.