• 제목/요약/키워드: Skin Resistance

검색결과 409건 처리시간 0.024초

자외선 차단능을 보유한 미세조류의 스크리닝 (Screening of Freshwater Microalgae for Resistance to Ultraviolet Radiation)

  • 한미애;한혜진;정문희;유림환;황채은;명수현;손윤진;윤영실;이철균
    • 한국해양바이오학회지
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    • 제6권2호
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    • pp.131-137
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    • 2014
  • Ultraviolet-B radiation (UV-B) in sunlight causes biological damages such as erythema and blister on skin. Microalgae have been in the limelight as an attractive feedstock for manufacturing functional materials. This study focused on screening microalga with protection ability against UV-B. The microalgae were isolated from local areas on April to June 2013 as well as June 2014. The cells were grown under continuous illumination from fluorescent lamps at $136.3{\pm}2.2{\mu}E/m^2/s$ in BG-11 medium at $15^{\circ}C$ for 12-14 days. The selected cells were spread on BG-11 agar and were exposed to UV-B (312 nm) for 20 and 25 minutes. The 13 strains among selected algae were classified. Among these, 9 strains were Scenedesmus sp. and the remains were Chlorella sp. Based on this study, it seems that Scenedesmus sp. and Chlorella sp. have resistibility against ultraviolet. These results will help to study on UV protection using microalgae.

존 월리엄 워터하우스 회화에 표현된 팜므 파탈 패션 이미지 (Femme Fatale's Fashion Image in John William Waterhouse's Works)

  • 남윤숙
    • 한국의상디자인학회지
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    • 제10권2호
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    • pp.11-25
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    • 2008
  • John William Waterhouse (1849-1917) is a painter renown for his romantic beautiful femme fatale images in the late 19th century in England. The purpose of this study is to examine the fashion in Waterhouse's femme fatale images. Waterhouse displays the devilism of femme fatale by the symbols of a wicked woman. He emphasized how wicked she is by means of water such as lake, river, and sea as well as symbols associated with demons such as forest, cave, naked woman, long hair, a monster-headed woman looking like an animal, water lily, and garden. On the other hand, he illustrates the woman's style as an image of a typical feminine beauty. Expressing naturally a fine-curved, immature girl's body with marvel-like white and clear skin in a kneeling down or crouching passive rose and depicting it as an innocent and fragile feminine image, he created a passive and lovely image of a young girl. With her eminent beauty and sex appeals, she lured men into danger. Words such as evil, women, and death had been used in describing her as femme fatale to emphasize her wickedness as well as to deliver the meaning across from the inside and to the outside. They also described her as a type of woman with body posture and fashion corresponding to the sexual ideology during the Victorian Age. His description of this fashion image was to show that femme fatale's fashion, which represents attraction and fatality, does not necessarily translate to an active fashion style that emphasizes sensuality. It also tends to minimize resistance and feelings of being threatened. Therefore, it allons us to acknowledge that even girlish body with innocent and frail-looking fashion can be a form of femme fatale, and that fashion styles is essential in forming the image of femininity.

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마이크로 프로세서 기반 Lock-In-Amp를 이용한 텍스타일 직물전극의 체온 측정에 관한 연구 (A Study on Body Temperature Measurement of Woven Textile Electrode Using Lock-In-Amp based on Microprocessor)

  • 이강휘;이성수;이정환;송하영
    • 전기학회논문지
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    • 제66권7호
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    • pp.1141-1148
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    • 2017
  • Generally, a thermistor made by sintering a metal oxide is widely used to measure the ambient temperature. This thermistor is widely used not only for industrial use but also for medical use because of its excellent sensitivity, durability, temperature change characteristics and low cost. In particular, the normal body temperature is 36.9 degrees relative to the armpit temperature, and it is most closely related to the circulating blood flow. Previous studies have shown that body temperature changes during biomechanical changes and body temperature changes by anomalous signs or illnesses. Therefore, in this study, we propose a Lock-In-Amp design to detect minute temperature changes of clothing and thermistor wired by a preacher as a method to regularly measure body temperature in daily life. Especially, it is designed to measure the minute resistance change of the thermistor according to body temperature change even in a low-cost microprocessor environment by using a micro-processor-based Lock-In-Amp, and a jacquard and the thermistor is arranged so as to be close to the side, so that the reference body temperature can be easily measured. The temperature was measured and stored in real time using short-range wireless communication for non - restraint temperature monitoring. A baby vest was made to verify its performance through temperature experiments for infants. The measurement of infant body temperature through the existing skin sensor or thermometer has limitations in monitoring infant body temperature for a long time without restriction. However, it can be overcome by using the embroidery fabric based micro temperature monitoring wireless monitoring device proposed in this study.

공기분사공법을 이용한 초대형 Open Caisson의 침하촉진에 대한 사례연구 (A Case Study on Settlement Promotion of a Large Size Open Caisson using Air-Jet an Method)

  • 정진섭;이종천;김해욱;김태형
    • 한국항해항만학회지
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    • 제33권3호
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    • pp.227-233
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    • 2009
  • 본 실험 연구는 공기분사공법의 오픈케이슨기초의 주면마찰력 저감효과에 대해 규명하기 위해 이루어졌다. 연육교 건설을 위해 기초로 사용된 공기구멍이 설치된 대구경 케이슨이 본 연구를 위해 이용되었다. 공기분사공법을 사용 시, 침하 시간을 줄일 수 있었으며 일반전인 방법으로 도달할 수 없는 깊이까지 침하를 시킬 수 있었다. 또한, 예상했던 것 보다 두 배 이상의 주면마찰저항력 저항 저감 효과를 얻었으며, 이런 장점 외 추가적인 외부의 재하하중 없이도 케이슨을 침하시킬 수 있음을 보여주었다. 그 외 오픈케이슨 침설 시 발파에 의한 케이슨 손상을 공기분사공법을 이용하면 방지할 수 있음을 보여주었다.

전압강하를 고려한 저압간선의 설계 알고리즘 (Algorithm for the Low-Voltage Feeder Design in Consideration of Voltage Drop)

  • 고영곤;최홍규;조계술
    • 조명전기설비학회논문지
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    • 제16권3호
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    • pp.84-92
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    • 2002
  • 저압간선의 굵기는 계통의 전압강하, 간선의 포설조건별 온도 보정계수를 적용한 허용 전류 및 간션의 임피 던스 값에 따라 결정된다. 따라서, 간선의 허용전류 값올 결정하기 위하여 간선의 포셜조건에 따른 적정 보정계 수가 적용되어야 하며, 저압간선의 정확한 임피던스 값을 분석하기 위하여 간선의 종류, 간선의 규격, 포셜조건 에 따른 온도, 표피효과 및 근접 효과 둥이 고려되어야 한다. 본 연구는 저압계통의 전압강하를 고려한 간선의 굵기 산정에 대한 체계적인 설계 흐름도를 제시 하였으며, 일반적인 계산 방식에 비하여 오차가 적은 계수로서 저압간선 굵기 선정 설계 실무에 적용할 수 있는 계산 방식을 연구하였다.

굽힘 하중을 받는 딤플형 내부구조 금속 샌드위치 판재의 최적설계변수의 수식화 및 파손선도 (Formulation of Optimal Design Parameters and Failure Map for Metallic Sandwich Plates with Inner Dimpled Shell Structure Subject to Bending Moment)

  • 성대용;정창균;윤석준;안동규;양동열
    • 한국정밀공학회지
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    • 제23권8호
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    • pp.127-136
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    • 2006
  • Metallic sandwich plates with inner dimpled shell subject to 3-point bending have been analyzed and then optimized for minimum weight. Inner dimpled shells can be easily fabricated by press or roll with high precision and bonded with same material skin sheets by resistance welding or adhesive bonding. Metallic sandwich plates with inner dimpled shell structure can be optimally designed for minimum weight subject to prescribed combination of bending and transverse shear loads. Fundamental findings for lightweight design are presented through constrained optimization. Failure responses of sandwich plates are predicted and formulated with an assumption of narrow sandwich beam theory. Failure is attributed to four kinds of mechanisms: face yielding, face buckling, dimple buckling and dimple collapse. Optimized shape of inner dimpled shell structure is a hemispherical shell to minimize weight without failure. It is demonstrated that bending stiffness of sandwich plate is 2 or 3 times larger than solid plates with the same strength. Failure mode boundaries and iso-strength lines dependent upon the geometry and yield strain of the material are plotted with respect to geometric parameters on the failure map. Because optimal parameters of maximum strength for given material weight can be selected from the map, analytic solutions for maximum strength are expressed as a function of only material property and proposed strength. These optimal parameters match well with numerical optimal parameters.

자동차 냉각기 호스용 EPDM 고무의 전기화학적 복합노화시험 및 고장메커니즘 (Electrochemical Combined-Stress Degradation Test and Failure Mechanisms of EPDM Rubber for Automotive Radiator Hoses)

  • 곽승범;최낙삼;신세문
    • 대한기계학회논문집A
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    • 제37권1호
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    • pp.1-8
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    • 2013
  • 자동차용 냉각기 고무호스는 열과 기계적 하중을 받으면서 국부적으로 형성된 전기적 영향으로 인해 노화와 고장이 발생한다. 본 연구에서는 개선된 시험방법을 이용하여 고무호스의 파괴거동을 재현하였다. 냉각기 고무호스 재료인 카본블랙이 함유된 EPDM 고무를 사용하여 인장응력과 전기화학적 복합 스트레스를 가하여 노화거동을 분석하였다. 노화 시간에 따른 전류 및 저항의 변화거동을 관찰하였으며 인장 변형 스트레스와 전압 및 노화온도 조건에 따른 노화거동을 분석하였다. 고무 시험편을 수직면으로 정밀하게 절단하여 시험편 표면 및 내부의 변화거동을 분석하여 전기화학적 노화거동과 고장메커니즘을 규명하였다.

A New Potato Cultivar "Early Valley", with High Yield and Early Maturity

  • Lim, H.T.;Dhital, S.P.;Khu, D.M.;Choi, S.P.;Kang, C.W.;Kim, T.J.;Mo, H.S.;Hwang, W.N.;Lee, W.J.
    • 한국육종학회지
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    • 제41권1호
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    • pp.61-67
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    • 2009
  • "Early Valley", is an early maturing potato cultivar with high yield potential. "Early Valley" is a clonal selection resulting from the cross between 'Suncrisp' and 'A87109-10'. It has medium plant height and light green foliage. "Early Valley" has medium flowering habit and white flowers. Tubers are smooth, yellow skin, light yellow flesh, round tuber shape, medium eye depth, and medium dormancy and good keeping quality. It has stable yield under wide range of climatic conditions. "Early Valley" is resistance to late blight, but moderately susceptible to common scab and hollow heart. This cultivar is also resistant to potato rotting at harvesting during the raining season. "Early Valley" has high level of antioxidant activity (about three times higher) and vitamin C (higher by 40%) than the 'Superior'. This cultivar has high level of tuber uniformity and capable of yielding 36.56 t/ha which is 17.07% higher than the control potato cultivar 'Superior' under optimum agronomical practices.

Effect of heat treatment on the structural characteristics and properties of silk sericin film

  • Park, Chun Jin;Um, In Chul
    • International Journal of Industrial Entomology and Biomaterials
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    • 제37권2호
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    • pp.36-42
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    • 2018
  • Recently, silk sericin has attracted attention because of its unique properties as a biomaterial, including its UV resistance, moisturizing effect on skin, and wound-healing effect. Therefore, the preparation of sericin in various forms such as gel, film, fiber, and sponge is studied for cosmetic and biomedical applications, and the effect of the preparation conditions on the structure and properties of sericin forms is examined to maximize its performance. In this study, silk sericin films were prepared under different preparation conditions and heat-treated at high temperatures ($100-250^{\circ}C$) to examine the effect of heat treatment on the film structure. The order of the crystallinity index of the untreated sericin film is as follows: F25 (sericin film cast from formic acid) > WE25 (ethanol treated sericin film cast from water at $250^{\circ}C$) > W25 (sericin film cast from water at $250^{\circ}C$) > W100 (sericin film cast from water at $100^{\circ}C$). As the heat-treatment temperature was increased, the color of the sericin films changed gradually from colorless to yellow, brown, and black depending on the temperature. The crystallinity of the sericin film changed after the heat treatment, depending on the preparation condition. Whereas a sericin film cast from formic acid (F25) started to lose its crystallinity at $200^{\circ}C$, thus undergoing the highest loss of crystallinity among the sericin films studied, the rest (W25, WE25, and W100) showed a decrease in crystallinity at $250^{\circ}C$, owing to the disruption of the ${\beta}$-sheet crystallites due to heat.

Creating damage tolerant intersections in composite structures using tufting and 3D woven connectors

  • Clegg, Harry M.;Dell'Anno, Giuseppe;Partridge, Ivana K.
    • Advances in aircraft and spacecraft science
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    • 제6권2호
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    • pp.145-156
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    • 2019
  • As the industrial desire for a step change in productivity within the manufacture of composite structures increases, so does the interest in Through-Thickness Reinforcement technologies. As manufacturers look to increase the production rate, whilst reducing cost, Through-Thickness Reinforcement technologies represent valid methods to reinforce structural joints, as well as providing a potential alternative to mechanical fastening and bolting. The use of tufting promises to resolve the typically low delamination resistance, which is necessary when it comes to creating intersections within complex composite structures. Emerging methods include the use of 3D woven connectors, and orthogonally intersecting fibre packs, with the components secured by the selective insertion of microfasteners in the form of tufts. Intersections of this type are prevalent in aeronautical applications, as a typical connection to be found in aircraft wing structures, and their intersections with the composite skin and other structural elements. The common practice is to create back-to-back composite "L's", or to utilise a machined metallic connector, mechanically fastened to the remainder of the structure. 3D woven connectors and selective Through-Thickness Reinforcement promise to increase the ultimate load that the structure can bear, whilst reducing manufacturing complexity, increasing the load carrying capability and facilitating the automated production of parts of the composite structure. This paper provides an overview of the currently available methods for creating intersections within composite structures and compares them to alternatives involving the use of 3D woven connectors, and the application of selective Through-Thickness Reinforcement for enhanced damage tolerance. The use of tufts is investigated, and their effect on the load carrying ability of the structure is examined. The results of mechanical tests are presented for each of the methods described, and their failure characteristics examined.