• Title/Summary/Keyword: Head-wear

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Ceramic-Ceramic Wear of Zirconia/Alumina Composites for the Application of Total Hip Replacement (인공 고관절 골두용 세라믹 복합재료에 대한 세라믹-세라믹 접촉 마멸 특성 분석)

  • Lee Kwon-Yong;Kim Hwan;Kim Dae-Jun;Lee Myong-Hyon;Seo Won-Seon
    • Tribology and Lubricants
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    • v.21 no.5
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    • pp.216-220
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    • 2005
  • The sliding wear behaviors of three different compositions of novel low temperature degradation-free zirconia/alumina (LTD-free Z/A) composites were examined in a ceramic-ceramic contact pair. The wear tests were performed by using a pin-on-disk type wear tester in a linear reciprocal sliding motion with a line contact in both dry and bovine serum lubricated conditions at room temperature. From the results of dry sliding wear tests, Z/A#1((5.3Y, 4.6Nb)-TZP/80 $vol\%Al_2O_3$) showed the best wear resistance among three kinds of LTD-free Z/A composites. For the bovine serum lubricated sliding wear tests, wear was too little to be measured for all kinds of Z/A composites. These novel LTD-free Z/A composites having excellent wear resistance demonstrated a potential as the alternative materials for the ceramic-ceramic contact pairs of femoral head and acetabular liner in total hip replacement.

Study on wear characteristics of commercialized HDD slider pad (상용 하드디스크 슬라이더 패드의 마모 특성에 관한 연구)

  • Jang, Cheol-Eun;Kim, Dae-Eun
    • Transactions of the Society of Information Storage Systems
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    • v.3 no.3
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    • pp.139-143
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    • 2007
  • In recent years new recording media and materials for head-disk interface (HDI) have been developed in order to increase the recording density of storage devices and decrease the cost of production. It is well known that HDI in hard disk drive (HDD) needs high durability and stability. The tribological characteristic of commercialized HDI systems is an important indicator of the HDD reliability. In this study, experimental investigation on the wear coefficient of commercialized hard disk slider pads was performed. The slider was placed on top of a hard disk and allowed to slide for a set distance. The wear of the pads was measured after the sliding tests. The result showed that the micro-bumps in commercialized HDD have extremely low wear coefficient of $10^{-11}$. The results of this work may be used for further development of the HDI technology for HDD.

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The Study About Formation-Process Of religious Dress And It's Ornament(I)-Forcusing On Ancient Egypt- (종교복식의 형성 과정에 관한 연구(I)-고대 이집트를 중심으로-)

  • 임상임;김현경
    • Journal of the Korean Society of Costume
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    • v.39
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    • pp.21-37
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    • 1998
  • This study researchs forms of Egyptian religious dress for studying formation-process of religious dress and its ornament. The study goes abreast literature and the very spot's materials also divides god's dress, priest's. Ancient an egytian worshiped mainly animals, step by step animal's humanization. So gods were expressed animal's face and human's body. Egypt god's costume is 1st, to take off upper hament and wear loin cloth on trousers 2nd only to wear short sheath skirt. 3rd to wear shout sheath skirt and to skirt and to wear loin cloth on there 4th to cover whole body and to open hand like mummy. Egype goddess' costume is largely to wear long sheath skirt up to the ankle and we can see selkit goddess's figure that wearing kalasiris after new dynesty. Priest had been a bald head and worn loin cloth and surrounded leopard's skin on there, but after the period of empire, worn a wig and worn less stoically. Also god had hung the lion's tail at symbol of the dignity and priest had put on sandals for a ceremony.

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Ceramic-Ceramic Wear Zirconia/Alumina Composites For The Application Of Total Hip Joint Implant (인공 고관절 골두용 세라믹 복합재료에 대한 세라믹-세라믹 접촉 마멸 특성 분석)

  • Kim H.;Lee K.Y.;Kim D. J.;Lee M. H.;Seo W. S.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2004.11a
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    • pp.355-361
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    • 2004
  • Ceramic femoral heads in the total hip replacement have been developed to reduce the polyethylene liner wear, Alumina and zirconia (3Y-TZP) having the excellent tribological properties are coupled against acetabular cups of polyethylene and are used in clinical application worldwide. However, alumina has a risk of catastrophic failure, and zirconia has the low temperature degradation in spite of enhanced fracture toughness. Recently, novel zirconia/alumina composite is very attractive due to the low temperature degradation (LTD)-free character and high fracture toughness. In the present study, we focus on the wear of ceramic on ceramic, which are able to be used as femoral heads and acetabular cups. Therefore, LTD-free zirconia/alumina composites with three compositions are made in a form of disk and cylinder, and the wear of the composites is performed on pin-on-disk type wear tester. The wear is conducted with or without lubricant. All the composites fabricated with the different composition show the good wear resistance.

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A Study on Head-Disk Interactions at Ultra-low Flying Height in Contact Start-Stop (Contact Start-Stop 방식에서의 극저부상 높이에서 Head-Disk Interface Interactions 연구)

  • 조언정
    • Tribology and Lubricants
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    • v.19 no.2
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    • pp.102-108
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    • 2003
  • The height of laser bumps has been considered as the limit of the minimum flying height in the contact start-stop (CSS) of hard disk drives. In this paper, tribological interactions at flying height under laser bumps are investigated in a spin stand for development of ultra-low flying head-disk interface. With the reduction of the spinning speed in a spin stand, the flying height is decreased under the height of laser bumps and, then, head-disk interactions are investigated using AE and stiction/friction signals. During seek tests and 20000 cycle-sweep tests, AE and stiction/friction signals are not significantly changed and there are no catastrophic failures of head-disk interface. Bearing analysis and AFM analysis show that there are signs of wear and plastic deformation on the disks. It is suggested that flying height could be as low as and, sometimes, lower than laser bump height.

A Study On the costume of the Koryo Dynasty (2)-$\cicled3$-See Through by the Human being, on the Buddist Painting of Koryo Dynasty Engraved Painting on the wood.- (고려시대 인물관련 제작물을 통해서 본 복식제도에 관한 연구(2)-고려시대 인물관련 제작 불화(佛畵)중 '경판화'를 통해서 본 복식제도에 관한 연구(2)-$\cicled3$-)

  • 임명미
    • Journal of the Korean Society of Costume
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    • v.26
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    • pp.221-232
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    • 1995
  • It was aimed to study the costume of Koryo dynasty based upon the one hundred and thirty four pictures of the engraved painting on the wood. The costume to study were made about 400 years during the King Mok-jong(1006) to the forth year of the king Wu based upon the Avatamaka Sutra and Pulsul-Yaesu 가) Men's wear 1. Hair style and hair dress ; Man tied up a top knot and they put on the hat such as a Kuan, Kun, and Mo. The young boys binds his hair up one, two, and three knots. 2. Clothes : 1) King wore an uniform of Mien-lu Kuan system. 2) The Crown Prince and high rank officials wore Yuan-yu-Kuan Won-jung-po-ju-Kuan, Sa-bang-Kuan, Yun-wha-Kuan and montain shape Po-ju-Kuan as a court dress. 3) Officials put on the Pok-du as an official dress and Won-jung-ip-mo, Kun and Mo as an everyday dress, the monk put on the diamond shape Do-kuan and Du-kun and the soldier put on the Helmet. Costume system of man was as follows ; They wore exchanged shape collar, big sleeve jacket, long skirt, apron, hanging precious stone big belt as a Mien-pok. 4) The soldiers wore helmet, Keun-Kap, Scarf, Pee-Bak, Hung-Kap, Pok-Kap, Yang-Dang-Kap, We-Yo-Kap, Kum-Kap, and caries arms. Lower-level officials wore Pe-Bal, Kun-Mo, gae, won-leung, very small sleve jacket, a long coat reaching up to the knee length, slacks, belt, loin cloth and apron. 5) Children's bind their hair up angle shape and wore a half long jacket raching up to the hip and slacks. 나) Women's wear; 1. hair style and hair dress; 1) High rank women's hair style was very extravaganceful. They made their hair top knot (one, two, or more knots) and decoraed precious stone, pan shape head dress, wheel shape head dress, and flower shape precious stone decorated head dress. 2. Clothes ; 1) High rank ladi's wore Kun-Kyun attached jacket, and jacket sleeves decorated pleats, and pleats decorated long skirt, apron, back apron, knot belt, scarf, this type is the same with Dang Dynasty, five dynasty of china, Song, Kum, Won, Myung Dynasty, and our costume of Poe-hae, and Shilla Dyansty. 2) Official ladies wore exchange shape collor, big sleeve jacket, long pleats skirt, apron, and back apron, scarf. 3) Women wore top knot hair style and decorated by ribbons. Shoulder scarf attached small sleeve jacket and wore reaching up to the knee length. Side seam is open and under wear was long skirt. 4) High knot hair style and exchanged shape collor jacket, under wear wore long skirt. They wore under skirts and the jackets. 5) High knot hair style, exchange shape collor jacket reaching up to the knee length small sleeve under wear wore long skirt, belt. 6) High knot hair style, big sleeve jacket and long skirt. 7) Foot wear wore boots, mokasin type shoes, sandal.

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Contact Stress Analysis of Artificial Hip Joints Using Finite Element Method (유한요소법을 이용한 인공 고관절의 접촉응력 해석에 관한 연구)

  • Kim, Chung-Kyun;Yoon, Jong-Deok
    • Tribology and Lubricants
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    • v.13 no.1
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    • pp.82-87
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    • 1997
  • The modern orthopaedics frequently uses the total hip replacement in the artificial hip joint. The wear in this joint requires a re-replacement of hip joints because it is under the severe load and friction conditions. To solve these problems the previous studies have been mainly focussed on the development of new materials. The research of new materials, however, needs much time and effort since it should be experimented for its bio-compatibility, friction, and wear characteristics. To reduce the work, in this study, the finite element analysis is applied to find new combinations of bio-materials in the total hip replacement which has the excellent contact characteristics. A non-linear FEM program MARC with 5-node axisymmetric element was used for analyzing the contact stresses between the hip joints. The computed results show that in case of acetabulum UHMWP has good characteristics, in femoral head, $Al_2O_3$, and in stem, Ti6Al4V.

A Study on the Contact Stress Analysis of the Artificial Hip Joint Using Finite Element Method (유한요소법을 이용한 인공 고관절의 접촉응력 해석에 관한 연구)

  • 김청균;윤종덕
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1996.10a
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    • pp.189-194
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    • 1996
  • The modern orthopaedics frequently uses the total hip replacement in the artificial hip joint. The wear in this joint requires the re-replacement of the hip joint beacuse it is under the severe load and friction conditions. To solve these problems the previous studies have been mainly focused on the development of the new materials. The research of new material, however, needs much time and effort since it should be experimented for its bio-compatibility, friction, and wear characteristics. To reduce the work, in this study, the finite element analysis is applied to find the new combination of the materials in the total hip replacement which has the excellent contact characteristics. The finite element uses MARC and the 5-node aximetric element. The results show that in case of acetabulum UHMWP has good characteristics, in femoral head, the $Al_2O_3$, and in stem, Ti6Al4V.

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A Study on the Characteristics of BTA Deep Drilling for Marine Part Carbon and Alloy Steels

  • Sim, Sung-Bo;Kim, Chi-Ok
    • International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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    • v.3 no.1
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    • pp.40-48
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    • 2000
  • The term "deep holes" is used to describe the machining of holes with a relatively large length to diameter ratio. The main feature of BTA deep hole drilling is the stabilization of cutting force necessary for the self guidance of the drill head. An additional feature is the cutting tool edges that are unsymmetrically placed on the drill head. There is an increasing necessity to predict the hole geometry and other dynamic stability behavior of deep hole drilling guidance. In this study, the effects of BTA deep hole drilling conditions on the hole profile machined piece are analyzed using domain analysis technique. The profile of deep hole drilled work piece is related to cutting speed, feed rate, chip flow, tool wear, and so on. This study deals with the experimental results obtained during the BTA drilling on SM45C, SM55C carbon steels and SCM440 steels under various cutting conditions, and these results are compared with analytical evaluations.aluations.

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A Study of Sports Fashion Image in Korea (한국 sports fashion image에 대한 연구)

  • 이은영
    • Journal of the Korea Fashion and Costume Design Association
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    • v.2 no.1
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    • pp.37-49
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    • 2000
  • Korean sports fashion began after 1990. after 1960, using vinyl, leather, plastic & metal material, Yve st. Laurent, Pierre Cardin, Andre Courrges, they lead sportive look. Head of 20th century, fashion was lead by haute­couture, after 60s. It was changed to pret­a poter. Now it can be called of american casual & sports fashion. This study would be a view of modem fashion trend and process of visualization in the future. I studied in reproduction of view & age of hyper media with visual circumstance & artistic background and mordern fashion trend & sports fashion image in korea. In conclusion, sports fashion image as visualizing aesthetic concept of modern fashion be defined as technology for man, for instance comfort, function, flexibility, simplicity and minimalism. Specically, Sports fashion was began satisfied for function after 90s, we can see variety of easy wear, hip-hop casual, entertainment sports wear, new street sports wear, luxury sports wear.

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