• 한국표면공학회지
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• 제35권6호
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• pp.408-414
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• 2002

TiN and TiAlN coating layer were deposited on WC-Co steel substrates by an arc ion plating(AIP) technique. The crystallinity and morphology for the deposited coating layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impact behaviors of the deposited TiN and TiAlN coating layer were investigated with a ball-on-plate impact tester. Beyond $10^2$ impact cycle, TiAlN coating layer showed superior impact wear resistance compared to TiN coating layer. On the other hand, both TiN and TiAlN coating layers started to be partially failed between $10^2$ and $10^3$ impact cycle. Above $10^3$ impact cycle, TiN and TiAlN coating layers showed similar impact behavior because of the substrate effect.

• Nuclear Engineering and Technology
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• 제39권6호
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• pp.737-746
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• 2007

A spacer grid, which is one of the most important structural components in a PWR fuel assembly, supports its fuel rods laterally and vertically. Based on in-house design experience, scrutiny of the design features of advanced nuclear fuels and the patents of other spacer grids, KAERI has devised its own spacer grid shapes and acquired patents. In this study, a performance evaluation of KAERI's spacer grid shapes was carried out from mechanical/structural and thermohydraulic view points. A comparative performance evaluation of commercial spacer grid shapes was also carried out. The comparisons addressed the spring characteristics, fuel rod vibration characteristics, fretting wear resistance, impact strength characteristics, CHF enhancement, and the pressure drop level of the spacer grid shapes. The results show that the performances of KAERI's spacer grid shapes are as good as or better than those of the commercial spacer grid shapes.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.851-852
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• 2004

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2003년도 춘계학술발표대회 요약집
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• pp.259-259
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• 2003

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.75-78
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• 2000

There are several effective factors to influence die life in the warm forging process. For instance process design die design and die materials etc This study presented heat treatment method which could improve toughness and wear resistance simultaneously in high temperature to apply high speed tool steels like SKH51 to die material for warm forging process. To verify the feasibility of application of heat treatment method mentioned above wear test was performed under the condition of constant time in 40$0^{\circ}C$ Wear coefficient was examined to search a relation between wear amount and time for each material and heat treatment method in 30, 60, and 130 minutes. To quantify the toughness-behavior between room and high temperature impact test was performed and heat fatigue test also fulfilled to compare with the resistance of heat check in room, 200, 400, and $600^{\circ}C$ temperature. On the basis of experimental results mentioned above high speed tool steel was applied to verify appropriateness of newly proposed heat treatment method for die of rotor pole used in automobile alternator. As a result die life of high speed tool steel applied newly proposed heat treatment is longer than that of STD61.

• 한국표면공학회지
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• 제57권2호
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• pp.105-114
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• 2024

Tempering behavior and mechanical properties in AISI H13 steel, quenched and tempered from 300 ℃ to 700 ℃ for different tempering time (1, 2, 5, 10, 20 hr) were quantitatively investigated by scanning electron microscopy (SEM), x-ray diffractometer (XRD), impact test machine, rockwell apparatus, ball-on-disk tester. Under the condition that the tempering time is 2 hours, the hardness increases slightly as the tempering temperature increases, but decreases rapidly when the tempering temperature exceeds 500 ℃, while the impact energy increases in proportion to the tempering temperature. Friction tests were conducted in dry condition with a load of 30 N, and the friction coefficient and wear rate according to tempering conditions were measured to prove the correlation with hardness and microstructure. In addition, primary tempering from 300 ℃ to 700 ℃ was performed at various times to establish a kinetic model to predict hardness under specific tempering conditions.

• 복식문화연구
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• 제20권6호
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• pp.895-911
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• 2012

The purpose of this study was to examine consumers' perceptions of eco-friendly children's-wear and their impact on the selection criteria for children's-wear and stores. A descriptive survey method using a self-administered questionnaire was employed. The sample consisted of mothers with children under the age of 13 residing in Seoul and the Gyeonggi area. Data were collected from September 2011 to October, 2011. The collected data were analyzed to find the differences between purchasers and non-purchasers of eco-friendly children's-wear in terms of their perceptions of eco-friendly children's-wear, as well as the influence of these perceptions on the consideration degree of criteria for the selection of children's wear and store. The results indicate that perceptions of eco-friendly children's-wear implied five key factors related to quality reliability, expected value, style, degree of recognition, and dissatisfaction with design and price. The results also revealed some differences between the group purchasing eco-friendly children's-wear and the group not purchasing eco-friendly children's-wear. These different perceptions were related to the aspects of quality reliability, expected value, style, degree of recognition. In general, the non-purchasing group displayed a lower mean score than the purchasing group. Both groups showed a low interest in aesthetic appreciation and the degree of recognition factor. The results showed that consumer's perceptions of eco-friendly children's-wear had an influence on the criteria for the selection of children's-wear and store type in both groups. Considering the findings of the study, it is clear that both purchasers and non-purchasers of eco-friendly children's-wear showed differences in their perceptions and purchasing behavior. Therefore, marketing strategies to appeal to the non-purchasing group should be differentiated from strategies used to ensure the loyalty of the purchasing group.

• 한국생산제조학회지
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• 제22권1호
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• pp.85-91
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• 2013

The machinability of wear-resistible tungsten carbides and the tool wear behavior in machining of V30 and V50 tungsten carbides using PCD (Poly Crystalline Diamond) cutting tool was investigated to understand machining characteristics. This material is one of the difficult-to-cut materials in present, but their usage has been already broadened to every commercial applications such as mining tools, and impact resistant tools etc. Summary of the results are as follows. (1) Tool wear progression of PCD tools in turning of wear-resistible tungsten carbides were observed specially fast in primary cutting distance within 10m. (2) Three components of cutting resistance in this research were different in balance from the ordinary cutting such as that cutting of steel or cast iron. Those were expressed large value by order of thrust force, principal force, feed force. (3) If presume from viewpoint of high efficient cutting within this research, a proper cutting speed was 15m/min and a proper feed rate was 0.1mm/rev. In this case, it was found that the tool life of PCD tool was cutting distance until 230m approximately. (4) In cutting of wear-resistible tungsten carbides such as V30 and V50, it was recognized that the tool wear rate of V30 was very fast as compared with V50. (5) When the depth of cut was 0.1mm, there was no influence of the feed rate on the feed force. And the feed force tended to decrease as the cutting distance was long, because the tool was worn and the tool edge retreated. (6) It was observed that the tungsten carbides were adhered to the flank.

• 한국의상디자인학회지
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• 제25권1호
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• pp.1-13
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• 2023

This study examines the effects of Chinese consumers' lifestyles on pursuing the benefits and purchase intentions for athleisure wear. Chinese female consumers aged 20 to 40 in Shanghai and Chengdu, who have purchased athleisure wear were selected for a survey, and 510 questionnaires were collected. Data was analyzed using SPSS 26.0 software. Factor analysis, reliability verification, regression analysis, and discrete analysis were performed. As a result, Chinese consumers' lifestyles were classified into three categories: 'personality orientation', 'show-off orientation', and 'health orientation'. There were four benefits: 'situation pursuit', 'practicality pursuit', 'fashion style pursuit', and 'appearance pursuit' for athleisure wear. Among the lifestyle types of Chinese consumers, "individuality-oriented" showed a positive effect on "pursuit of practicality", "pursuit of situation", "pursuit of fashion style", and "pursuit of appearance" among the benefits of pursuing athleisure wear. Next, among lifestyle types, 'show-off orientation' showed a positive effect on 'individuality' and 'appearance pursuit'. Finally, among lifestyle types, 'health-oriented' showed a positive effect on 'pursuit of practicality' and 'pursuit of appearance'. On the other hand, Chinese consumers' lifestyle types of "show-off," "health-oriented," and "individuality-oriented" all exhibited a significant impact on their purchase intention for athleisure wear. According to age groups and location, there is no significant difference in terms of 'lifestyle', 'athleisure wear pursuit benefits' and 'purchase intention'. Compared married women and unmarried women, it was found that unmarried women value their health and leisure, while those with a lower their educational background, considered the lifestyle of "individuality-oriented" and "show-off-oriented", as well as "situation-pursuit", "practicality", and "fashion style pursuit".

• 열처리공학회지
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• 제28권5호
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• pp.239-249
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• 2015

Various amount of NbC carbide was intentionally formed in a matrix-type cold-work tool steel by controlled amount of Nb and C addition. And the effect of NbC addition on the mechanical properties was investigated. Four alloys with different Nb and C contents were cast by vacuum induction melting, then hot forging and spheroidizing annealing were conducted. The machinability of the annealed specimens was examined with 3 different cutting tools. And tensile tests at room temperature were conducted. After quenching and tempering, hardness and impact toughness were measured, while wear resistance was evaluated by disk-on-plate type wear test. The increasing amount of NbC addition resulted in degraded machinability with increased strength, whereas the absence of NbC also led to poor machinability due to high toughness. After quenching and tempering, the additional NbC improved wear resistance with increasing hardness, whereas it deteriorated impact toughness. Therefore, it could be found that a moderate addition of NbC was desirable for the balanced combination of mechanical properties.