• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1311-1312
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• 2006

Diamond tools were fabricated by cold pressing and sintering under pressure at the temperature up to $750^{\circ}C$. Investigation of the microhardness behaviour of the segments was showed that increasing the cobalt ratio causes the increase of the hardness of the matrix material. This caused to decrease of the wear rate of the matrix. Because the matrix wears more slowly than the diamonds, the space between the cutting edges and the matrix is constantly reduced. The swarf cannot be carried away properly, and the segment will continuously lose its ability to cut with higher cobalt contents.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.570-571
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• 2006

The mixed atomized iron powders with 0.3% graphite and 1% Ni powders were cold pressed and sintered at $1200^{\circ}C$ for 30 min under pure Ar gas atmosphere. Some of the sintered specimens were intercritically annealed at $760^{\circ}C$ and quenched in water (single quenching). The other sintered specimens were first fully austenized at $890^{\circ}C$ and water quenched. These specimens were then intercritically annealed at $760^{\circ}C$ and re-quenched in water. The experimental results showed that the wear coefficient effectively decreased in the double quenched specimen.

• Journal of Biomedical Engineering Research
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• v.17 no.1
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• pp.11-18
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• 1996

The toxic metal ion release behaviour and the cytotoxicity of a super stainless steel (S.S.S, 22cr-20Ni -6Mo-0.25N) were investigated The measurement of the amount of static and wear- induced trace metal ion released from the steels was conducted in Hank's balanced salt solution using an electrothermal atomic absdrption spectrometry equiped with Uaphite furnace. And the in vitro cytotoxicity of the materials was assesed in cell culture. The static dissolution rates of Fe and Cr ions from the S.S.S were significantly lower than those of 316L SS. However, the Ni ion release from the S.S.S during the first 4 weeks was yester than that from 316L 55 by 15-45%. Also, the wear-in- duces dissolution rates from the steels were not correlated either with their elemental composition rates or with the static metal ion release rates. The S.S.S did not deteriorate the osteoblasts viability. And no toxic response was observed from the macrophages cultured for 7 days in RFMI 1640 medium immersed with the S.S.S specimens.

• The Korean Journal of Ceramics
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• v.3 no.1
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• pp.47-51
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• 1997

The dense sintered bodies of Si/SiC composite with various Si contents could be fabricated by changing the green density in the forming process. The Si/SiC/graphite composites with various graphite contents could be also fabricated by changing a graphite content in the starting composition. Their mechanical and tribological properties were characterized and wear mechanism was also studided. The hardness and strength of the Si/SiC and the Si/SiC/graphite were decreased with increasing the contents of free Si and graphite, respectively. However, the friction coefficient and specific wear rate had no specific relations to their hardness and strength. Adhesion of free Si was a main factor to determine a wear resistance of the Si/SiC composite. In the case of the Si/SiC/graphite, solid lubricationl and liquid reservoir of the graphite particles played the main role of the reduction of the friction force. In the torque test to estimate the possibility of practical of practical applications, the value of torque between the Al2O3 disk and Si/SiC/graphite disk was 1/6 lower compared with two $Al_2O_3$ disks on the basis of 100,000 cycles.

• The Research Journal of the Costume Culture
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• v.6 no.3
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• pp.111-125
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• 1998

What human beings wear is closely related to how they conceptualize their bodies and how they classify the group they belong to and the way they wear their cloth s an important cultural element that shows wearers' awareness and social relationship. Especially, underclothes reflect unrevealed cultural inside of the society more abundantly than outer wear do. Through such characteristics of underclothes, we are able to better understand inherent order of culture. This study si to understand the characteristics and changes of Korean culture by reviewing the convention of underclothes wearing that takes important role in clothing without being explicitly revealed. For this study, in addition to biblical review of under clothes of traditional societies, a total of 301 college students aging from 19 to 28, who are the most open to accepting new cultures and changes, residing in Seoul area were participant. Questionnaire consists of open-ended questions of underclothes terms, kinds, why they wear, items of wearing, how they obtained, how they take care of, etc. In conclusion, changes in cultural meaning of underclothes analyzed through convention of underclothes wearing are as follows; 1) changes in wearing pattern implies changes in functions of underclothes and changes in members' roles and values in a society; 2) changes in recognition of underclothes are related to the changes in awareness of sex; 3) consumer behaviour of underclothes represents a part of information culture; 4) changes in the pattern of maintaining underclothes show that differentiation of sex role in household tasks is decreased.

• Korean Journal of Human Ecology
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• v.10 no.1
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• pp.113-126
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• 2001

The purpose of this study was to investigate clothing behavior and ornaments wear of university students. The subject of this study consists of 241 college students who were attended in Kongju National University. SPSSWIN Program was utilized to calculated frequency(N), mean value(M) and standard deviation(SD) for statistical analysis. Differences among the populations were examined through T-test, F-test, $x^2$-test. The results of this study were as follow : 1. Clothing behavior of university students had significant difference according to sex, grade. In general, female students showed higher score than did male students in clothing interest, clothing conformity, self-estimation about clothing, clothing dependence, clothing aesthetic, clothing modesty, A first-year students had high tendency in clothing interest. 2. The wear of ornaments had significant difference according to variables. Buying the ornaments, most of students sot information in show window and emphasized on design. Male students wanted to have the ornaments of shoes, watch, hat & necklet, but female students wanted to have the ornaments of shoes, earring, necklet & hairpin. 3. Clothing behavior has Influenced university students' ornaments wear. The university students who appeared to be interested in clothes were apparently influenced by peers when selecting ornaments. Ornaments were usually bought in the department store, while belts were among the most popular choices. Students who stressed color when purchasing ornaments showed a high level of interest in and dependence on clothes. On the basic of these results, we can conclude that university students' taste in clothing behavior and use of ornaments wear depend on several different factors. Therefore, it is possible to outline the shift in clothing attitudes during adolescence. In order to understand university students' behaviour concerning clothes, much guidance and various studies on the subject are much recommended.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.45-50
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• 2000

While braking cars, a large amount of energy is taken into the brake system in a short period of time. This leads to some problems ; cracking of the disc, non-uniform wear of pad and disc, fade. Thus it is important to measure the contact thermal behaviour precisely between disc and pad. The measurements must be considered to design the brake system. The paper describes methods to analysis the problem of the thermal behavior on the ventilated disc with ANSYS-a program of FEA and a brake dynamometer. According to this way, the paper can present the error between the data by the dynamometer and the results of analysis by ANSYS.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.114-115
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• 2006

[ $FerroTitanit^{(R)}$ ] is an extremely high alloyed PM material containing about 20 to 35 wt.% titanium based carbides. Such materials are designed to achieve a high wear resistance, but the high volume fraction of hard phases causes a comparable low ductility in case of tensile loading. In the present study the mechanical properties of different Ferro-Titanit grades (variations in chemical composition and in heat treatment) were investigated by means of tensile tests. The mechanical properties and the fracture behaviour will be related to the chemical composition, the heat treatment and the microstructure.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.10a
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• pp.110-116
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• 1997

The tribological behaviour of WS$_2$ solid lubricant was investigated using a ball-on-disk type tester. The WS$_2$ powder was spray-coated at room temperature and the effects of specimen configuration, atmosphere, applied load and rotating spccd on the friction coefficient was examined. WS$_2$ coated ball and disk showed the lowest friction coefficient of 0.05 in the nitrogen atmosphere under 0.3 kgf and 100 rpm, whereas relatively high coefficient of 0.1 - 0.15 was observed in air atmosphere. This confirmed that the spray-coated WS$_2$ solid lubricant was effective in reducing the friction coefficient and improving wear life in nitrogen atmosphere.

• Tribology and Lubricants
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• v.10 no.4
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• pp.51-58
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• 1994

Condition monitoring technology has recently been received much attention in the light of its significance on the maintenance of complex machineries such as turbines in power plants. Currently, turbines in power plants are maintained by scheduled overhaul based on the manufacturer's recommendations and the utility's experience. Although this preventive maintenance is known to be very effective, operators have less access to identify failure of elements when it happens between overhaul period. Therefore, in this study, a development of a on-line condition monitoring system through wear debris analysis of lubricating oils is aimed with a view to detecting abnormal wear behaviour of bearings and other wet-components at an early stage, allowing better outage scheduling and minimizing forced outages. For field application purposes, the on-line system developed was installed on the turbine of the No.4 unit at Ulsan Power Plant and its performance has been evaluated on site.