• KSTLE International Journal
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• v.2 no.1
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• pp.17-21
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• 2001

Surface treatment technologies are frequently used to improve mechanical properties of surface layers of machinery components in many practical situations. Surface hardness of piston in the oil hydraulic piston pumps is very important about wear resistance. To improve hardness, wear resistance of the oil hydraulic axial piston pump, it is needed to know the surface layer characteristics in the sliding contact parts. This paper reports an experimental study on surface treatment characteristics in the piston of the oil hydraulic axial piston pump. We investigated the surface wear of a piston between untreated and nitriding-treated surfaces. We obviously observed that the surface hardness of piston in the oil hydraulic axial piston pump plays an important role to have wear resistance and remain a longer life.

• Journal of Korea Foundry Society
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• v.9 no.3
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• pp.237-246
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• 1989

This study has been carried out to investigate the difference of rolling life and rolling wear characteristics for various high strength ductile iron castings under unlubricative dry rolling condition by Amsler type wear test with 9.09% sliding ratio. The tensile strength of the castings have been obtained 80, 90 and $100kg.f/mm^2$ as cast-state with pearlitic, bainitic and martensitic matrix structures alloyed with Mo, Cu and Ni. It has been found that the amount of rolling wear is decreased when the tensile strength and hardnees of the castings are increased. The amount of rolling wear is increased, when the maximum compressive stress are increased. The maximum weight loss ratio of rolling wear of the castings are same at the 70000 numbers of revolution with out the maximum compressive stress.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.209-212
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• 2002

The wear process of end mill is a so complicated process that a more reliable technique is required for the monitoring and controling the tool life and its performance. This research presents a new tool wear monitoring method based on the sound signal generated on the machining. The experiment carried out continuous-side-milling for 4 cases using the high-speed steel slot drill under wet condition. The sound pressure was measured at 0.5m from the cutting zone by a dynamic microphone, and was analyzed at frequency domain. The tooth passing frequency appears as a harmonics form, and end mill wear is related with the first harmonic. It can be concluded from the result that the tool wear is correlate with the intensity of the measured sound at tooth passing frequency estimation of end mill wear using sound is possible through frequency analysis at tooth passing frequency under the given circumstances.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.181-182
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• 2002

Most recent, Plasma ceramic spray is used on parts of tribosystem, has been investigated on the tribological performance. The application of ceramic coatings by plasma spray has become essential in tribosystems to produce better wear resistance and longer life in various conditions. The purpose of this work was to investigate the wear behavior of $8%Y_2O_3-ZrO_2$ coating due to temperatures of post-spay heat treatment. The plasma-sprayed $8%Y_2O_3--Zirconia$ coating was idiscussed to know the relationship between phase transformations and temperatures of post- spray heat treatment. Wear tests was carried out with ball on disk type on normal load of 50N, 70N and 90N under room temperature. The transformation of phase and the value of residual stress were measured by X-ray diffraction method(XRD). Tribological characteristics and wear mechanisms of coatings was observed by SEM. The tribologieal wear performance was discussed a point of view for residual stress. Consequently. post-spray heat treatment plays an important role in decreasing residual stress. Residual stress in coating system has a significant influence on the wear mechanism of coating.

• KSTLE International Journal
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• v.6 no.2
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• pp.45-50
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• 2005

Plasma ceramic spray that is applied on a machine part under severe work conditions has been investigated for tribological behavior. The application of ceramic coatings by plasma spray has become essential in tribosystems to produce wear resistance and long life in severe conditions. The purpose of this study was to investigate the wear characteristics of $8\%Y_{2}O_3-ZrO_2$ coating, in view of the effect of post-spay heat treatment. The plasma-sprayed $8\%Y_{2}O_3-ZrO_2$ coating was studied to know the relationship between phase transformations and wear behavior related to post-spray heat treatment. Wear test was carried out with ball on disk type on normal loads of 50N,70N and 90N under room temperature. The phase transformation of phase and the value of residual stress were measured by X-ray diffraction method(XRD). Tribological characteristics and wear mechanisms of coatings were observed by SEM. The tribological wear performance was discussed in the focusing of residual stress. Consequently, post-spray heat treatment plays an important role in decreasing residual stress. Residual stress in the coating system has a significant influence on the wear mechanism of coating.

• Journal of Applied Reliability
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• v.13 no.3
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• pp.165-174
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• 2013

Thruster break for aerogenerator performs a role that is stopping the rotor in case of emergency such as strong wind, system abnormality or maintenance check. In this study, failure analysis and test evaluation on the thruster break for aerogenerator are proposed, and the entire process to improve reliability of the product through design improvement is presented. The typical failure case is fatigue and wear, and failure cause on these are identified and improvement plan is presented. Lastly, reliability improvement is established to analyse test results before after the life test.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.3
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• pp.59-65
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• 2002

In the grinding process, the degree of the sharpness in wheel grain affects the surface roughness and the dimensional accuracy. If a wheel with dull grains is used, te grinding force will be increased and the surface roughness deteriorated. To produce a precision component, the magnitude of parameters related to the wear amount of a grinding wheel has to be limited. In this study, a variation of the grinding force and the surface roughness were measured to seek the machining characteristics of the WA and CBN wheels. From the wear amount of the grinding wheel and the removal rate of workpiece, the grinding ratio was calculated. And also the wheel life was determined at a rapid decreasing point of the grinding ratio. The difference between the surface of wheel-workpiece before grinding and after wheel life was clearly verified with a microscopic photo.

• Journal of the Korean Society of Costume
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• v.54 no.4
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• pp.85-95
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• 2004

The Purpose of this study was to find a phase of clothing in Korean proverb. The results of the analysis of this research was as follows： In the case of headgear, was expose that symbolize handsomeness, conduct of life, personality that display charm and position which is not usage as only head protection. Upper wear was expressing aspect and person's similarity, and was symbolizing conduct of life by meaning of dress and its ornaments according to a person that dress displays that change. Trousers(bottom wear) was expose that it means aspect or conduct of life(a 4 case, 40％) through site. Overcoat showed that overcoat that is clothes that is symbolizing wearer's situation, aspect and wear most on face because is involved with behavior that is not right in clothes usage is used by standard that foretell personality. Underwear can know that expressed being involved with right behavior, nature by the basic clothes. I was able to know that I express an attitude of a life or a form through shoe, and the accessories won an minor order but that I have a large influence on a character or the appearance of a person. Silk fabrics expresses Position, and hemp cloth expressed by symbol that display ability. Also, silk fabrics had meaning that hint person's background. Dress and its ornaments that is used in proverb by these result can know that have function as symbolic symbol that display Person's nature or situation, aspect that is wearing clothes that is not function as only simple clothes.

• Design & Manufacturing
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• v.17 no.1
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• pp.7-12
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• 2023

Recently, with the emergence of the 4th industrial revolution, the demand for smart factories and factory automation is increasing. In this study, a tool life prediction program was developed to select optimal machining conditions using CNC milling equipment, which is widely used in flexible production and automation. The equipment used in the experiment was Hwacheon Machine Tool's 5-axis machining equipment, and the tool used was a 17F2R tool. For the machining path, the down-milling cutting method was selected and long-term machining was performed. The analysis standard for side wear on the tool was set at 0.1 to 0.2 mm, and tool life data and wear data were obtained in the cutting experiment. The program was created through the data obtained from the experiment, and a prediction rate of over 90% was secured when comparing the experimental data and the predicted data.

• Journal of Fashion Business
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• v.6 no.6
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• pp.19-33
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• 2002

In the middle of economic and mental riches in the 21st century, the importance of well being and the pursuit of happiness are emerging as the new trend. Thus the lifestyle that values comfortable and practical naturalness and intrinsic merits has come to influence the human life rather than the old showing-off and formal desire. In addition to this, the spread of the five day week has given more leisure time, which has led to the increasing interest in health and leisure. The interest in sports has skyrocketed since the successful holding of the 2002 Korea and Japan World Cup event. All these changes to the lifestyle have contributed to the fusion of luxury wear and sports wear. As the result of the consumers in the 21st century having more classified and upgraded way of living thanks to the settlement of the above-mentioned lifestyle and the enlargement of the leisure sports culture, there has appeared the wellness kin, who value the importance of life and the nature and believe in the idea that they can reconstruct the environment in the way they can enjoy their lifestyle and pursue happiness. They favor healthy fashion items and think much of exercise, nutrition, and rest. They pursue the natural and comfortable style, whose ideas came from simple exercises such as health training and yoga and the easy and comfortable look observed at resorts. Their fashion style can be divided into three of fitness fashion, yoga fashion and resort fashion. First, the boxer fashion is characterized by the relaxing design and practicality. The major items of the fashion include running shirt-styled upper clothes, training pants, hooded shirts and sneakers. Simple and comfortable look should be induced from the combination of the items. Second, the yoga fashion was motivated by the comfortable yoga wear. It advocates stress-free spirit and comfortable and stable naturalism. Along with the advantages of the good feeling to wear and the functionality to help exercise better, the yoga fashion gives the wearer enough room to move around in, using the unique lines. Third, the resort wear refers to the kinds of clothes you tend to wear at the beach and the park. There are various kinds of the resort look; bathing suits, the beach wear you can wear with the bathing suit, the resort evening wear, the full-side look that you try on top of the bathing suit and is made of the same material of the bathing suit, and the marine look, the symbol of the summer. In short, the study attempted to investigate many trends occurring as the result of human recent increasing interest and concern in the quality of life, and the impacts of them on the fashion world. This kind of research that examines the background of the times and society will help to grasp with the fashion trends of the present and the future. And more studies should be conducted on the development of new and original design in clothes fashion, which reflects the characteristics identified in this kind of research.