• 한국진공학회:학술대회논문집
• /
• 한국진공학회 1998년도 제14회 학술발표회 논문개요집
• /
• pp.44-44
• /
• 1998

It was observed that the friction coefficient decreased with increasing Si concentration in the l ilms. Furthermore, the friction behavior became more s때ble even when very small amount of S Si of less than 0.5 at. % was incorporatA:회 By analyzing the composition of the debris f formed, we could show that the low and stabilized friction coefficient is in마nately relatA:었 w with the formation of the Si rich oxide debris. These result supports the mechanism that the h hydrated silica debris is the reason for low friction coefficient in humid environment. Second e evidence of the role of Si rich oxide debris could be found in the triOO-chemical reactions d during initial stage of triho-test. When the Si concen$\sigma$ation was less than 5 at.%, initial t transient period of high friction coefficient was commonly observed. Mter the transient period, m the friction coefficient becomes lower with increasing contact cycles. The initial $\sigma$ansient p peri여 becomes shorter and the starting and maximum friction coefficients in $\sigma$ansient 야,riod d decreased with increasing Si concentration. Composition of the debris on the wear scar s surface was analyzed by Auger spe따'Oscopy at v뼈ous stages in the initial transient period. W We observed that when the friction coefficient increased in earlier stage of the $\sigma$'ansient p period, iron and oxygen was observed in the debris. However, decrease in the 당iction c coefficient in the later stage of the transient period was associated with the formation of s silicon rich oxide debris. This result also supports the friction mechanism of Si-DLC films t that the formation of Si rich oxide debris results in low friction coefficient in ambient a atmosphere. atmosphere.

• 한국생산제조학회지
• /
• 제18권4호
• /
• pp.436-441
• /
• 2009

An air filter is a device to remove dust from the air supplied to the automotive engine. A requirement for the optimum air filter is to improve the capability to remove particles from the air it takes in, that is the efficiency and amount of dust collection. By removing dust from the air, the air filter prevents the engine cylinder from wear, reduces ventilation resistance, and thus improves engine output and guarantees intake performance. In order to guarantee such air filter performance, it is very important to properly seal the air filter. For passenger cars made in Korea, the air filters are fabricated with steel caps as their frames are large and their engine capacity is big. Recently however, European countries and Japan started using urethane for manufacturing the air filter, so that all foreign-made cars now have urethane filters. The urethanes used for air filters are applied in two ways: One is to use soft urethane for both top and bottom of the air filter and the other is to use soft urethane for the top and hard urethane for the bottom. Each of these method has unique problems. In this study, hard urethane is used for both top and bottom of the filter in order to improve those problems and increase the sealing efficiency. Especially for the top, NBR (rubber mold) is pre-settled in tough urethane and then the urethane is solidified through foaming, which makes it possible to develop a solid and double-sealed filter.

• 한국의류산업학회지
• /
• 제6권5호
• /
• pp.613-617
• /
• 2004

The intent of this study was to determine whether different light exposure could modify the clothing behavior in the evening cold environment or not. Nine female subjects volunteered to this study. In a bright light or a dim light condition, light intensity was controlled 3000 lx or 10 lx respectively. Subjects were introduced to wear various kinds of garments whenever they need to feel comfortable as the room temperature began to decrease. The room temperature was lowered from $30^{\circ}C$ to $15^{\circ}C$ for one hour (21:00 h~22:00 h) and maintained at $15^{\circ}C$ for additional one hour (22:00 h~23:00 h). Subjects stayed in chamber from 08:00 to the next day 07:00. Clothing behavior, core temperature, subjective temperature sensation and melatonin secretion were measured. Most subjects put on the clothing more quickly and more thickerly in the bright light rather than in the dim light condition. The fall of core temperature during night was significantly less under the bright light in the late afternoon, suggesting that the set-point of core temperature has been set at a higher level during the evening and the night, being supported by the less amount of melatonin secretion. Thus, it is concluded that the quicker dressing behavior with thicker clothing in the "Bright" condition is advantageous in evening cold exposure, since it enables the core temperature to reach its set-point value more easily.

• 한국의류학회지
• /
• 제32권5호
• /
• pp.846-858
• /
• 2008

This study was designed to propose a method to draft bodice block pattern from 3D body scan data. Subjects were ten elderly women in their 60's, who wear basic size(B: 94cm, W: 82cm) garment. Scanning was done using 3D whole body scanner(WB4, Cyberware). Measurements for 3D data and cross section were attained using Auto CAD, by which a upper bodice pattern for elderly women was drawn on the basis of short measured method. The results are as following: As for most items, no significant differences were shown between measurements from Martin's anthropometry and those from 3D scan data, suggesting measurement from 3D scan data could be used to draft a pattern. The drafting equations acquired were as follows; width of pattern=B/2+5.5, width of waist=W/2+3.5cm, dart amount=8cm. Dart distributions were 23%(B.P.) : 20%(front armpit) : 17%(side seam) : 18%(back armpit) : 15%(back protruded point) : 7% (center back line). Through wearing test using 5-point Likert scale, resultant pattern was evaluated as appropriate for elderly women's pattern to get over 4 point. As a result, it might be said that 3D scanning application is effective for elderly women in that it doesn't take time so much as Martin's anthropometry and that their body shape vary compared with those of young women.

• 대한소아치과학회지
• /
• 제23권2호
• /
• pp.389-400
• /
• 1996

In Class II amalgam restoration in deciduous molar, failure rate and incidence of recurrent caries are high as children become older. In order to preserve deciduous molars till the physiologic exfoliation time, stainless steel crown is a choice of the treatment. As a result of a careless treatment, such as overhanging margin, poor marginal adaptation, poor proximal contour and inadequate mesiodistal width give rise to interfering eruption of the adjacent teeth, recurrent caries and chronic gingival irritation and insufficient arch length respectively. In this study, 252 s.s. crowned teeth extracted due to physiologic exfoliation or periapical lesion. The purpose of this study is to analyze the marginal adaptation of stainless steel crown to the deciduous molar in order to obtain better clinical result. The results were as follows : 1. Between the length of s.s. crown and the marginal gap of crown, positive correlations were shown. 2. Largest amount of marginal gap was shown at buccal side in upper deciduous molars and lower first deciduous molar, lingual side in lower second deciduous molar. But no significant diffrence were found statistically compared to second most largest one. 3. Incidence of exposed restoration and recurrent caries were higher in proximal surface than buccal/lingual surface. And extension of restoration below the margin of s.s. crown gives rise to higher rate of recurrent caries. 4. Defect of contour was found in 34%, frequently found in lower 1st deciduous molar and upper 1st deciduous molar. 5. Marginal polishing defects were found in 23%. 6. Ledge was formed in 10% especially in lower 1st deciduous molar and lower 2nd deciduous molar. 7. 16% of the teeth had wear facet due to traumatic occlusion, 7% of them had occlusal perforation.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 1994년도 춘계학술대회강연 및 발표대회 강연및 발표논문 초록집
• /
• pp.6-6
• /
• 1994

Har dmaterials such as cemented carbides with or without coated layer, cermets, ceramics and diamond or c-BN high pressure sintered compact are used for cutting tools, wear -resistant parts, rock drilling bits and/or high pressure vessels. These hardmaterials contain not only hard phase, but also second consituent as the element for forming ductile phase and/or sintering aid, and the mechanical properties of each material depend on (1) the amount of the second constituent as well as (2) the grain size of the hard phase. The hardness of each material mainly depends on these two factors. The fracture strength, however, largely depends on other microstructur a1 factors as well as the above two factors. For all hardmaterials, the fracture strength is consider ably affected by (3) the size of microstructur a1 defect which acts as the fracture source. In cemented carbides, the following factors which are generated mainly due to the addition of the second constituent are also important; (4) the variation of the carbon content in the normal phase region free from V-phase and graphite phase, (5) the precipitation of $Co_3$ during heating at about $800^{\circ}C$,(6) the domain size of binder phase, and (7) the formation of ${\beta}$-free layer or Co-rich layer near the surface of sintered compacts. For cemented carbides coated with thin hard substance, the important factors are as follows; (8) the kind of coated substance, (9) the formation of ${\eta}$-phase layer at the interface between coated layer and substrate, (10) the type of residual stress (tension or compression) in the coated layer which depends on the kind of coating method (CVD or PVD), and (11) the properties of the substrate, and (12) the combination, coherency and periodicity of multi-layers. In the lecture, the details of these factors and their effect on the strength will be explained.

• 구강회복응용과학지
• /
• 제32권3호
• /
• pp.224-231
• /
• 2016

과도한 치아의 마모는 치아의 병적 변화, 교합 불균형, 기능 및 심미적 문제를 일으키며 악관절과 근육의 문제를 일으킬 수 있는 수직고경의 감소를 야기할 수도 있다. 수직고경의 감소가 발생한 경우, 전악보철수복을 통해 수직고경을 회복시켜 주기 위해서는 정확한 진단이 중요하다. 본 증례는 59세 남성으로 전반적인 치아의 마모와 파절로 인한 수직고경의 감소 및 비심미성을 해결하기 위해 전악 지르코니아 보철 수복을 시행하였다. 생리적 안정위, 견치간 거리 등을 분석하여 수직고경을 3 mm 거상하기로 하였고 전악 왁스업 후 임시치관을 제작하여 6개월동안 사용한 뒤 이를 이용하여 지르코니아 최종 보철을 완성하였다. 1년 6개월 경과 관찰하여 만족스러운 결과를 얻었기에 보고하는 바이다.

• 한국의류산업학회지
• /
• 제8권3호
• /
• pp.269-274
• /
• 2006

The purpose of this study is to examine the costumes and trading goods of the Korean envoys in 1811. The findings of the study are as follows: The Korean envoys, as shown in literature, were dressed up three different types of costumes: Pyongbok, Gongbok, Jobok. They put on different kinds of clothes depending on the purpose of the events such as for ceremonial purpose or for traveling purpose. For traveling purpose, the envoys wore Pyongbok like Waryonggwan and Hakchangeui, which were commonly used as Pyeonbok in those times of Chosun era. For ceremonial purpose, they chose to wear Danryeong, Gongbok, Geumgwanjobok in this order following the order of the importance of the ceremony. The design of Jobok and Gongbok of Jeongsa and Busa were different from that of the early Chosun era. This difference in the Jobok and Gongbok demonstrates that Gwanbok has been transformed with the change in the general Po system in the late Chosun era. When the costumes of Korean envoys in 1811 were compared to those in 1711, there were similarities in terms of the design of Jobok and Gongbok, which indicated that little had changed for the period of 100 years. The most popular exchanged Byeolpok of Chosun was articles of clothing such as Daeyuja, Daedanja, Baekjeopo, Sangjeopo, and Baekmyeonju, while that of Japan was mostly objects of craftwork and a small amount of Po. The fact that cloth was one of the main items from the early Chosun era to the early 19C shows the highly developed clothing culture of Chosun era.

• 한국의류산업학회지
• /
• 제17권2호
• /
• pp.295-304
• /
• 2015

This paper investigated wear comfort property of heat storage knitted fabrics for high emotional garment. For this purpose, ZrC imbedded PET knitted fabric was prepared and various physical properties such as thermal, wicking and drying characteristics were measured. In addition, far-infrared emission characteristics of ZrC imbedded PET was analysed and tactile hand property and dye affinity of ZrC imbedded knitted fabric were also studied in comparison with regular and other commercial heat storage PET knitted fabrics. It was observed that Zr imbedded amount in the yarn was 19.29% by ingredient analysis and far-infrared emission energy was $3.65{\times}10^2W/m^2$, emissivity was 0.906 at the range of wavelength $6{\sim}20{\mu}m$. It was found that maximum heat flow (Qmax) of ZrC imbedded PET knitted fabric was lower than that of regular PET one and warmth keepability rate was higher than that of regular PET one, which means ZrC imbedded PET have heat storage property. Drying property of ZrC imbedded knitted fabric was better than that of regular PET one due to heat by far-infrared emitted from ZrC in the core of filament. It revealed that wicking property of the ZrC imbedded fabric was not influenced by far-infrared emission, but affected by fibre physical properties. Tactile hand property of ZrC imbedded knitted fabric was not influenced by imbedding ZrC in the filament but affected preferably by structure of knitted fabric. Dye affinity of ZrC imbedded PET knitted fabric was less influenced by dyeing temperature and time than regular PET knitted one.

• 패션비즈니스
• /
• 제19권5호
• /
• pp.1-16
• /
• 2015

The appearances and geometry structures of knitted fabrics have important effects on their functions as textile fabrics. Structural design of the woven fabric, prior to the manufacturing processes in the weaving mill, often leads to a similar predictable appearance in the final outcome with the corresponding weave design. The increase of the employment of elastic textile yarns in knitting fabrics for comfort stretch or outdoor sports wear knit products has, however, resulted in difficulties in predicting the final appearance of the knit structure design. Due to the stretchability and exceptional recovery behavior of the elastic yarns such as polyurethane elastomeric yarns, the appearance of the final product often differs from the initial knit design. At textile CAD program for preparing tricot knit designs has been employed in this study to predict the two dimensional appearance of the design. The similarities between the designs and corresponding knit products seem to be acceptable for the two-dimensional textile CAD program in this study. However, when elastomeric yarns are partially employed in the polyester filament tricot product, a considerable amount of departure from the design is apparent due to the constriction and/or deformation of property differences in the elastomeric yarns and polyester filament yarns. Therefore, another purpose of this study is to measure the departure of the final tricot product from the initial tricot design, especially in the case employing elastomeric yarns in the knit structure together with regular polyester filament yarns. For measuring the three-dimensional departure, a 3D scanning system has been used for the mesh reconstruction of the fabric specimen. Hopefully, the result from this study will be used as a guide to modify and improve the current textile CAD program proposed for the two-dimensional simulation of the tricot.