• The Journal of Korean Academy of Prosthodontics
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• v.38 no.4
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• pp.438-445
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• 2000

The ideal restorative material should mimic the properties of the tissues it replaces. Dental composite resins have been used widely as restorative materials due to its advantages such as excellent esthetics and ease of manipulation. But inadequate wear resistance has been a major factor limiting the use of composite restorative materials. Improved manufacturing techniques have allowed the development of hybrid composites, with a greater percentage volume filler loading, which have improved physical and mechanical properties. However they are lacking in the study of wear resistance. The purpose of this study was to evaluate the wear of human enamel against ceromer by the use of a pin-on-disk type wear testers. Discs of ceromer(Targis ; lvoclar Vivadent, Amherst. NY) and discs of type III gold alloy as a control were used f9r test specimens. Intact cusp of premolar and molar were used for enamel specimens. The wear of enamel was determined by weigh-ing the cusp before and after each test, and the weight converted to volumes by average densi-ty of enamel. Surface profilometer was used to quantify wear of the ceromer and gold specimens. Vicker's hardness tester was used to evaluate the surface hardness of test specimens. The SEM was used to evaluate the wear surfaces The results were as follows; 1. Ceromer produced less enamel wear than gold(p<0.05) 2. The wear volume of ceromer was greater than that of gold(p<0.01) 3. The hardess of ceromer was lower than that of gold, but there was no correlation between the hardness and wear of the ceromer and gold. 4. SEM analysis revealed that there were many voids and microcracks in the wear tract of ceromer In gold group, many minute V-shaped grooves were examined.

• Journal of Applied Reliability
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• v.18 no.3
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• pp.193-200
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• 2018

Purpose: In this study, the life of the motor is investigated by performing the accelerated life test with the brush wear of the industrial cleaner motor as the main failure mode. Methods: The accelerating stress factor of the accelerated life test is a voltage, which can increase the number of revolutions of the motor to accelerate the brush wear due to the friction between the brush and the commutator. Also, the accelerating stress level was determined after determining the maximum allowable level of the voltage through the preliminary test. Results: The motor failure time at each accelerating stress level was predicted by regression analysis with brush wear length as performance degradation data. The main failure mode, which is brush wear, of the motor was reproduced by this test. The shape parameter of the Weibull distribution was confirmed to be the same statistically at all accelerating stress levels by the likelihood ratio test. Conclusion: The life of the motor was investigated by performing the accelerated life test with the brush wear of the industrial cleaner motor as the main failure mode. Through the accelerating test method of the cleaner motor, various life expectancy and life expectancy of the acceleration factor are predicted.

• Fashion & Textile Research Journal
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• v.15 no.2
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• pp.268-276
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• 2013

This study identifies how people use bicycle wear, complaints about bicycle wear, and functions required for bicycle riding. This survey was conducted with bicycle club members (men and women) in their twenties to sixties who ride bicycles on a regular basis. A total of 373 subjects responded to questionnaires and 326 responses were used for further data analysis. The data was analyzed by descriptive analysis, multiple response analysis, crosstabulation analysis, factor analysis, reliability analysis, and one-way ANOVA. The results are as follow: First, the people surveyed were primarily men, young adults and middle-aged people. They ride bicycles mainly to participate in club activities, to exercise, and to spend their spare time with a well-being trend that focuses on leisure and health. Second, they often utilize bicycle wear when they ride bicycles. They are aware of bicycle wear brands. In addition, a majority have purchased bicycle wear that shows a very high awareness of bicycle wear. Third, as for complaints about bicycle wear worn when riding bicycles, a majority of people answered that the waist part of the top pulls up and they feel sore with the bottom part of the pants when riding bicycles for a long time. They also answered that it is inconvenient to put belongings in both tops and pants. Fourth, there is a high demand for safety-related functions for bicycle riding in regards to the functions required for bicycle wear. In addition, a majority of the members showed a customer awareness of functional bicycle wear and intended to purchase bicycle wear equipped with smart functions.

• Journal of the Korean Society of Clothing and Textiles
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• v.15 no.1
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• pp.61-69
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• 1991

In order to investigate the comfort properties of aerobic wear with different materials, the physiological responses, subjective wear sensation and microclimate were measured. The experimental garment were all-in·one type with half·length sleeves made of cotton/ polyurethane and nylon/ polyhrethane fabrics. The conditions of the experimental room were controlled to maintain two type of environ- ments, i.e. $25{\pm}1^{\circ}C$, $60{\pm}5\%$ R. H. and $30{\pm}1^{\circ}C$, $70{\pm}5\%$ R.H., Air velocity was maintained at 0.25 misec all the time. The results are as follows; 1) At $25^{\circ}C$, mean skin temperature and comfort sensation were not significantly different among 2 types of materials. 2) At $30^{\circ}C$, aerobic wear made of cotton/polyurethane fibers showed better pleasant tactile sensation than that of nylon/polyurethane fibers. 3) Under both environmental conditions, microclimate of two types of aerobic wear was not significantly different. 4) Among several aspects of wear sensations, tactile sensation was the most powerful factor to differenciate material differences of aerobic wear.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.2
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• pp.299-308
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• 1996

In order to epidemiologically verify the tensile that cervical abfraction is developed from the tensile stress during lateral excursion, comparisons between the experimental group with cervical abfraction and the control group without cervical abfaction was made by exmining the occlusal wear and patterns from the dental cast. 1. The degree of occlusal wear in the experimental group with cervical abfraction was higher than that of control group without cervical abfraction.(p<0.05) 2. No significant difference in the occlusal wear pattern was found between the experimental group and the control group. 3. Higher degree of occlusal wear was found in the age group of abov 40 than that of below 40.(p<0.05) 4. There was a correlation between the degree of occlusal wear and the degree of cevical abfraction.(p<0.05) 5. There was a correlation between the age and the degree of cevical abfraction.(p<0.05) It can be concluded that occlusal stress is the etiologic factor of cervical abfraction, but no clear distinction was made between the relationship of tensile stress and cervical abfraction.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.316-322
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• 2004

Wear volume was used generally to analyze the moving state of lubricated machine. But It is difficult of getting the correct wear volume because wear volume of it is progressed always unstably with a large amplitude on working condition. If correct analysis of wear volume on working condition for lubricated machine can be possible, it can be effect on diagnosis of failure condition. The purpose of this study is carried out to analysis friction factors affecting on wear volume for prediction of failure condition of alloy steel for machine structural use by design of experiment. The results show that the most important friction factors affecting on wear volume was applied load, neat sliding distance, sliding speed and materials.

• Tribology and Lubricants
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• v.16 no.4
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• pp.282-288
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• 2000

A sliding friction and wear test for silicon nitride (Si,N4) was conducted using a ball-on-disk specimen configuration. The material used in this study was HIPed silicon nitride. The tests were carried out from room temperature to 1000$^{\circ}C$ using self-mated silicon nitride couples in laboratory air. The worn surfaces were observed by SEM and the debris particles from the worn surfaces were analyzed for oxidation by XPS. The normal load was found to have a more significant influence on the friction coefficient of the silicon nitride than an elevated temperature. The specific wear rate was found to decrease along with the sliding distance. The specific wear rate at 29.4 N and 1000$^{\circ}C$ was 292 times larger than that at room temperature. The main wear mechanism from room temperature to 750$^{\circ}C$ was caused by brittle fracture whereas from 750$^{\circ}C$ to 1000$^{\circ}C$ the wear mechanism was mainly influenced by the oxidation of silicon nitride due to the increased temperature. The oxidation of silicon nitride at a high temperature was a significant factor in the wear increase.

• Fashion & Textile Research Journal
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• v.19 no.5
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• pp.579-588
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• 2017

This study investigates the wearing behavior and athleisure wear design preferences of women in their twenties as related to the design development of athleisure wear. A questionnaire survey was conducted on 185 women in their 20s. The survey was conducted from September to October 2016. Questionnaire items consisted of respondents' general items, athleisure wear and preference related items, and athleisure wear purchase related items. We collected 185 questionnaires from participants; subsequently, 169 were used as analytical data (except for incomplete questionnaires). The results of the study are as follows. Fit and wear comfort was the most important factor in the selection of athleisure wear. As a result of investigating the popularity of the athletic wear brand, the preference for the total sportswear brand was higher than the professional athletic wear brand. When the preferred colors were examined, the achromatic colors were ranked higher than chromatic colors. An examination of the preferred designs according to items indicated that the bra top preferred the 'U' shaped front plate and the 'Y' base basic type; in addition, T-shirts with the round neckline and the 1/4 length sleeves were preferred as tops. Leggings preferred long length type. It is necessary to develop a brand that matches the preference of the twenties' consumers by adjusting the aged target that can avoid the overheated competition and develop a niche market.

• Fashion & Textile Research Journal
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• v.21 no.5
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• pp.597-605
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• 2019

This paper examined the garment formability and appearance of perspiration absorption, fast dry, and breathable fabrics. The mechanical properties and seam pucker properties of these fabrics were measured and regression analysis was conducted between fabric structural parameters and their mechanical and seam pucker properties. The superior total appearance value (TAV) of fast dry knitted fabrics for sports-wear was achieved in fabrics with high extensibility and bending rigidity; consequently, it increased with increasing stitch density and tightness factor. The formability of the fast dry knitted fabric also improved with an increasing stitch density and tightness factor. The seam pucker was influenced by bending rigidity and a good seam pucker was exhibited in the fast dry knitted fabrics with low stitch density and tightness factor. However, the formability (F) of the breathable fabric improved by increasing extensibility and bending rigidity that decreased with an increasing cover factor and the thickness of the breathable fabric. In addition, seam pucker deteriorated with an increasing cover factor and the thickness of the breathable fabric, which was similar to the results of the formability predicted in fabric mechanical properties. A superior seam pucker was achieved in fabrics with high extensibility and low bending rigidity.

• Journal of the Korean Society of Costume
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• v.58 no.10
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• pp.135-147
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• 2008

The purposes of this study were to segment consumers by Korean image perceptions and to investigate the differences among the segmented groups in regard to Korean image preferences in casual wear The subjects of the study were 653 women consumers who lived in Seoul. Data were collected from July to September, 2007. Statistical analyses used in the study were factor analysis, cluster analysis, ANOVA, and Duncan test. The results showed that there were four factors of Korean image perceptions: natural, feminine, passionate, and simple images. Based on the four factors, the consumers were segmented into three groups. They were natural image perception group, low interest group, and feminine image perception group. The results showed that there were significant differences among the segmented groups in regard to Korean image preferences In casual wear. For example, natural image perception group prefer diverse Korean prints, blue and green colors, natural fabrics, and diverse casual types for their Korean image casual wear. In the meanwhile, feminine image perception group generally prefer soft fabrics, red and purple colors in their Korean image casual wear.