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AN EXPERIMENTAL STUDY ON THE EFFECTS OF DOG'S PULPAL HEALING AFTER COBALT-60 IRRADIATION (성견에 있어서 Cobalt-60 조사가 치수치유과정에 미치는 영향에 관한 연구)

  • Park, Dong-Soo
    • Restorative Dentistry and Endodontics
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    • v.9 no.1
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    • pp.15-24
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    • 1983
  • Irradiation is frequently employed as the sole therapy for oral cancer. These irradiated patients presents peculiar and progressive dental problems. But there is only scanty informations concerning specific approaches to endodontic treatment for head and neck cancer patients who have been subjected to tumorcidal doses of radiation therapy. The purpose of the present study was to determine the effects of cobalt-60 radiation on the pulpal healing of dogs after the direct pulp capping. As the experimental animals, 10 dogs (above 7-8 months after birth) were divided into 3 groups (Control, Group I, Group II). The cobalt-60 was irradiated to the Group I and Group II each 1,009 and 1,562.5 rads as single dose. As the capping material Dycal$^{(R)}$(L.D. Caulk company) was selected. After the direct pulp capping the dogs were sacrified 1, 2, 3, 4, week interval and made the original slides cut with a thickness of 8 microns and stained with hematoxylin and eosin. After examination and comparision of all specimen, the results of this study were drawn as follows; 1. The formation of reparative dentin was observed from the 1st week in the Control group, the 2nd week in the Group I & II. The few and irregular tuble structure was appeared in the 4th week in the Control group only, but failed in the Group I & II. 2. The continuity of dentin bridge was appeared in the 3rd week in all group and the degeneration of odontoblast in the 1st week of the Group II. 3. The congestion and hemorrhage in the pulp tissue were observed in all groups until 3rd week. The inflammation was appeared within the 2nd week in the Group I and especially marked in the Group II, but absent in the Control group. 4. In cases Dycal into the pulp tissue deeply, the local necrosis of pulp and decrease of dentin formation was observed.

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Variation of Axial Tension-Compression Fatigue Characteristics by UNSM on Ti-6Al-4V (Ti-6Al-4V재의 UNSM처리에 의한 축인장압축피로특성변화)

  • Suh, Chang-Min;Cho, Sung-Am;Pyoun, Young-Sik;Suh, Min-Soo
    • Journal of Ocean Engineering and Technology
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    • v.25 no.6
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    • pp.42-48
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    • 2011
  • The present study makes three original contributions to nanoskinned Ti-6Al-4V materials. The nanoskins were fabricated on Ti-6Al-4V material using various surface treatments: deep rolling (DR), laser shot peening (LSP), and ultrasonic nanocrystal surface modification (UNSM). These surface treatments are newly developed techniques and are becoming more popular in industrial fields. A fatigue strength comparison at up to 106 cycles was conducted on these nanoskinned Ti-6Al-4V materials. Fatigue tests were carried out using MTS under axial loading tension-compression fatigue (R = -1, RT, 5 Hz, sinusoidal wave). The analysis of the crack initiation patterns in the nanoskinned Ti-6Al-4V materials found an interior originating crack pattern and surface originating crack type. Microscopic observation was mainly used to investigate the fatigue fractured sites. These surface modification techniques have been widely adopted, primarily because of the robust grade of their mechanical properties. These are mainly the result of the formation of a large-scale, deep, and useful compressive residual stress, the formation of nanocrystals by the severe plastic deformation (SPD) at the subsurface layer, and the increase in surface hardness.

Color Changes in Natural-Dyed Fabrics for Inference of the Original Color -through Repetitive Washing- (천연염색물의 본래색 추정을 위한 변퇴색 경로에 관한 연구 -반복세탁을 중심으로-)

  • 박명자;윤양노
    • Journal of the Korea Fashion and Costume Design Association
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    • v.4 no.3
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    • pp.9-15
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    • 2002
  • Compared with synthetic dyes, natural dyes have inferior colorfastness as a result of the exposure of the material to any environment that may be encountered during the processing, testing, storage, display or use of the dyed materials. Especially, colors on fabrics fade excessively after washing. Therefore, it is problem to infer the historic textiles with natural-dyed fabrics. The object of this study is to analyse the factors affected to colorfastness and color change during washing. In experimental, fifteen natural dyes were dyed by the Korean traditional dyeing methods onto natural fiber fabrics: cotton, silk, ramie, and flex. Total 49 dyed fabrics in combination with dyes and fibers were used for the specimen. The Launder-Ometer was used for evaluating the effects of exposure to repetitive washing from 1 to 20 washing cycles (KS K 0430). Color difference(ΔE) in the CIEL*A*B* color-order system were determined by spectrophotometer at 100 bserver. Washing caused significant changes in the color of natural-dyed fabrics. The degree and nature of color changes on the fabrics were dependent on the combination of fiber and the dye type used. The groups of violet(Lithospermum erythrorhizon Sieb.et Zucc) and black color(Ailanthus altissima Swingle, Phus trichocarpa Miq) yielded excellent colorfastness to repetitive washing. The group of indigo blue color(Polygonum tinctorium Lour.) was also very resistant to color change in washing except silk. Whereas the dye groups of Red, Yellow, Orange, Brown colors indicated greatest changes in color, particularly Carthamus tinctorius L.

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Development and Practical Use of Rubblization Method (원위치파쇄기층화 공법의 개발 및 실용화 연구)

  • Ko, Seok-Beom;Kim, Kyung-Taek;Lee, Young-Chul;Lee, Seung-Woo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.10a
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    • pp.405-416
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    • 2005
  • The rubblization technique is breaking the aged concrete pavement slab into rubblized concrete aggregate, and use it as an base material at its original position, then builds overlay above the rubblized base. This method has been successively used in USA due to the advantage of good contructibility, cost-effectiveness as well as the capability of preventing of reflection cracks. However, constructibility and economic performance of rubblization on typical Korean concrete pavements needed to be investigate since to typical Korean concrete pavements have thick slab, as well include lean concrete subbase course. This stud explored optimum breaking depth and suggested minimum 10cm based on reflection crack simulation test. Also proper head shape and impact energy were investigated based on small breaking field tests. It was found that $127kg/cm^2$ of stress with 52.3% of head contact area are breaking requirement. Also, Multi-head type breaker suitable for Korean condition was designed and developed. This multi-head type breaker was designed to rubblize old concrete to the suggested optimum rubblized-depth and rubblized-concrete-aggregate size to prevent reflection crack and maintain high bearing capacity. This machine was used for the test of rubblization of old concrete pavement on a non-use old concrete and a in-serviced road. In these two tests, engineering properties of rubblized base and constructability and cost were investigated. In both tests, the old concrete rubblized to targeted size and depth, and high-level bearing capacity was achieved. Also, superior constructability and lower cost compared with traditional reconstruction was examined.

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A Study on Woman's Warming Hood of Chosun Dynasty - Mainly from 1800's till 1930's - (조선조(朝鮮朝) 여인(女人)의 난모(暖帽)에 관한 연구(硏究) - 1800년(年)${\sim}$1930년대(年代)를 중심(中心)으로 -)

  • Kwon, Yeong-Soon;Lee, Kyung-Ja
    • Journal of the Korean Society of Costume
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    • v.2
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    • pp.35-50
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    • 1978
  • This paper is an observation on the woman's warming hoods such as Nambawi, Pungchae, Ahyam, Jnbawi and Gullae worn form 1800's through 1930's. At the late era of Chosun dynasty, The every day lifes of people were greatly influenced by invasion of western world, in particular the styles of clothing are changed from original one to Western-like. So the hoods of our own's were dissappcared gradually, and the interests of them were reduced accordingly by the western culture invaded. Therefore this paper is intended to participate in the study of clothing culture by considering of hoods, one of the almost disappeared clothes, and review the wisdom and sense of beauty of our ancestor by unique ornament. The warming hoods in this paper are from a category of ear-protection gear and also deformed from man's one. The ear-protection gear was a warming hood from Tae Jong, the king of the early era of Chosun, and usage classifications of them were strict according to the class division at the early and mid era of Chosun, but generally diminised at the late era, thery were used freely, but the differences in decorations represented the division of the rich and poor. General feature of it is open top, but covers all of head and is used for warming clothes, with has many decorations on it, this decorative tendency was more clear at the late era. Namely, the shape had been modified from tough one to modish one, and fur, the material of it, are from stiff and long to soft short and well refined. This warming hoods were used until 1930's then disappeared by the population of western mufflers and wraps. Jobawi is now already forgotten even its name except for the ornament in picturing the baby in first birth day. In revewing the consideration of warming hoods mentioned. It is found that the subtlety of the ancestor, and there are supplication for the happiness of life even in the decorations.

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A Study on the Eroticism Expressed in Fashion in the 1990s (1990년대 의상에 표현된 에로티시즘에 관한 연구)

  • 손미희;임영자
    • Journal of the Korean Society of Costume
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    • v.26
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    • pp.29-47
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    • 1995
  • Today, we live in the fastly changing society, rapidly developing scientific civilization and repeatly confusing political culture. Therefore, man persuits the emotional rest in "eros" and sympathizes with eroticism. Such an eroticism represents too much in art and costume all over the world. the purpose of this study is to classify the ex-pressive style of eroticism which is the feature of the costume in the first year of 1990's and to analyze its expression meaning. This study will be a basic data of new design development and help predict the costume in the latter half of the yeat. The method of this study was performed by using the literature related to the eroticism and the study of preceeding researchers. To analyze the costume style the its implied meaning being used to express the eroticism of 1990's, the magazines(Elle, Vogue, WWD, Collections etc) and the literatures related to fashion were used. The styles and meaning of eroticism expressed eroticism by using the minimal design which exposes wholly or partly by using a transparent vinyl and a see-through clothing. The sexy style arose from the expression of social rebellion and the exposure of suppressive sex as a psychological repulsion against the older generation. 2) Deshabille style : This style is the conver-sion to the outer garment of an underwear. The excessive exposure which just concerns the inti-mate parts of the body by using the thin cloth or lace for an underwear. This style can be recognized as the beauty destruction and ugly 3) Glamour style : The style is made up of the high-grade cloth such as silk and velvet and expresses the bodily beauty. This style falls into a rebellious culture and comes from the inten-tional expression to escape the modern life which is straight and hard. 4) metallic style : This style uses variously the new material such as vinyl-coating, enamel and represents the eroticism through the original expressions.pressions.

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The Study on the Intercalation-Deintercalation of Potassium-Carbon Fiber Intercalation Compounds (칼륨-탄소섬유층간화합물의 Intercalation-Deintercalation에 관한 연구)

  • Oh, Won-Chun;Cho, Sung-Jun;Choi, Young-Jai;Ko, Young-Shin
    • Analytical Science and Technology
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    • v.7 no.2
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    • pp.193-199
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    • 1994
  • We have synthesized K-CFICs by the modified two-bulb method. These synthesized compound were analysed with X-ray diffractometer and UV/VIS spectrophotometer. According to X-ray diffraction analysis, the intercalation of potassium between the carbon layers of carbon fiber was better then other intercalants. From obtained data for this deintercalation process, we can see that a number of potassiums were presented as a residue between the carbon layers and this residue compounds had a stability for a long term. Therefore, it is appear that these compounds have a capability as new useful material. From UV/VIS spectrometry data, we can suppose that spectrum of K-CFICs synthesized at $250^{\circ}C$ had only a $R_{min}$, and spectra of any other compounds were not appeared charecteristic peaks because potassium ions were little affect the energy levels of original carbon fiber.

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Evaluation of Nondestructive Diagnosis and Material Characteristics of Stone Lantern at Damyang Gaeseonsaji Temple Site in Korea

  • Lee, Chan Hee;Araki, Naruto
    • Journal of Conservation Science
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    • v.35 no.4
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    • pp.279-293
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    • 2019
  • The stone lantern of the Damyang Gaeseonsaji temple site is a cultural heritage built during the Unified Silla period (AD 868). The reason for its value as a cultural property is due to wittern the background and the period created on inscription of the lamp stone engraved by letters. The stone lantern consists of two types of lithic tuffs for the 23 original properties, the replaced stones in 1991, and the biotite granite for its ground stones replaced in 2005. The lithic tuffs selected as the replacement parts in 1991 and 2017 have been examined and got to properties of hardly exposure moisture as well as very similar geochemical characteristics. There were various types of physical deterioration of the stone properties and structural cracks; in particular, on the northern side of the stylobates. Chemical and biological deterioration can be identified as black, white, and brown discolorations as well as by the presence of lichens, bryophytes, and herbaceous plants. In the evaluation of the physical properties of the stone lantern, the mean and maximum ultrasonic velocities were found to be similar in each direction. However, the lowest velocity on the east and south sides were found to be lower than those of other stone properties. It was found that physical damage to the stylobates resulted from water expansion in a freeze-to-thaw phenomena related to water content. Therefore, dismantling repair was carried out in the protection facility to restrict further water supply to the stone as much as possible.

Effects of the Freeze-thaw Process on the Strength Characteristics of Soils (IV) -Insulation Performance beneath the Freezed Tested Banking by Inclusion of Insulation Material- (동결-융해작용이 흙의 강도특성에 미치는 영향 (IV) - 단열재를 삽입한 동결성토의 단열거동 -)

  • 유능환;박승범;유영선
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.32 no.3
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    • pp.39-46
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    • 1990
  • This paper was analized the thermal conductivity of polystylene (TENSAR- GEOGRID) embeding into the subbase through frost penetration depth, frost heave, change of bearing capacity, and soil moisture movement due to freezing, thawing and icing actions, and their results were as follows : 1.The change of temperature into the sub-base was much increased by the Tensar-Geogrid insertion, and the frost penetration and frost heave were decreased as the thinner of the insulation thickness but the thawing velocity of melting period was appeared to be faster in case of non-insulated. 2.The frost heave had a close relationship with the thickness of insulations which was reasonably included anti-frost effects. 3.The moisture content during the freezing period of upper layer of the insulation insertion was increased by 15 per cent but it was returned to initial state of the thawing period, and at the down layer temporarily increased by 10 per cent and returned to the original state at once. 4.The insulation was acted as a function of distribution of surcharge, and the settlement of the sub-base was about 1.5 mm under 15 tonnage of load and which was included within the allowable limits. 5.The sliding resistance due to the icing which was induced by the insulation insertion into the sub-base was appeared as more 40 per cent than noninsulation area, so that the insulations should be restricted on the place such as mountains, curved and cross area which were required the braking power under the traffics.

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Analyzing the Disaster Management Service in the Perspective of Disaster Victims as a Demander: An Approach Based on Grounded Theory (재난관리서비스에 대한 수요자의 반응분석: 근거이론적 접근)

  • Yoo, Hyun-Jung;Lee, Jae-Eun
    • The Journal of the Korea Contents Association
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    • v.9 no.5
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    • pp.265-276
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    • 2009
  • Many disaster management actors participate in the disaster sites and they do their best for the best result in their given position. They recover the disaster-stricken area, endeavor to prevent the disaster's relapse, and to rescue and protect the disaster victims. Ultimately, the purpose of their role and effort is to support a physical aid as well as material aid for that disaster victims can return their living condition to the original one before the disaster. However, the disaster management services have been provided in the supplier's view till now. Subsequently, despite significant efforts, providers have failed to comprehend what would be the victim's demand and how to reflect that in the disaster management service. In this paper, we approached and analyzed the recent disaster management service in the way of grounded theory, and endeavored to find the solution which disaster victims preferred. As a result of analysis, we found 184 concepts, 28 sub-categories, and 9 categories which could explain the victims' desired solution. We found that "an imperfect restoration which causes disaster" and "pain of the disaster field" would be main categories among them.