• 제목/요약/키워드: light elements

검색결과 838건 처리시간 0.034초

First records of Hemicyclops tanakai Itoh and Nishida, 2002 and Tisbe ensifer Fischer, 1860 (Crustacea, Copepoda) in Korea

  • Karanovic, Tomislav;Lee, Wonchoel
    • Journal of Species Research
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    • 제5권3호
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    • pp.289-299
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    • 2016
  • Extensive survey of invertebrates in Korea, led by the National Institute of Biological Resources in Incheon, continues to uncover many new and endemic species, but also elements of neighbouring faunas that were previously unknown here. Hemicyclops tanakai Itoh and Nishida, 2002 was originally described from estuarine mud-flats in Tokyo Bay, Japan. We report one male and two females from a sandy beach on Jeju Island, which represent its first record in Korea and second record ever. No morphological differences were observed between these two disjunct populations, so we expect more records of this species in Korea and Japan. Tisbe ensifer Fischer, 1860 was originally described from Madeira and later on reported from numerous other parts of the Northern Atlantic, as well as from the Indian Ocean. We report two females from a shallow littoral in Sokcho, which represents its first record in Korea and the first record in the entire Pacific Ocean. Because of morphological discrepancies reported in previous records we recognize that this species might be in reality a species complex, and we only tentatively identify our Korean specimens as T. cf. ensifer. We provide numerous light photographs of both species in addition to short descriptions, in hope that they might elucidate global problems of their zoogeography and dispersal of small marine invertebrates in general. Further samplings from Korea and other parts of the world will be necessary to test our identifications and phylogenetic relationships of Korean populations with molecular and other tools.

Study on the Performance of Laser Welded joint of Aluminum alloys for Car Body

  • Kutsuna, Muneharu;Kitamura, Shuhei;Shibata, Kimihiro;Salamoto, Hiroki;Tsushima, Kenji
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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    • pp.620-625
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    • 2002
  • Considering the fuel consumption of car, a light structure of aluminum alloys is desired for car body nowadays. However, fusion welding of aluminum alloys has some problems of reduction of joint efficiency, porosity formation and hot cracking. ill the present work, investigation to improve the joint performance of laser welded joint has been carried out by addition of Cu, Ni, and Zr to A6N01 alloy welds. Aluminum alloy plate of 2.0mm in thickness with filler metal bar was welded by twin beam Nd:YAG laser facility (total power:5kW). The filler metals were prepared by changing the chemical compositions for adding the elements into the weld metal. Thirteen filler metal bars were prepared and pre-placed into the base metal before welding. Ar gas shielding with a flow rate of 10 l/min was used. The defocusing distance is kept at 0 mm. At travel speeds of 3 to 9 m/min and at laser power of 5kW (front beam 2kW rear beam 3kW), full penetration welds were obtained, whereas at travel speeds of 12 to 18 m/min and same power, partial penetration was observed. The joint efficiency of laser-welded joint was improved by the addition of Cu, Ni, and Zr due to the solid solution hardening, grain refining and precipitation hardening. The type of hardening has been further considered by metallurgical examination.

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환경요소를 고려한 공동주택 단지계획요소 도출 및 가중치 평가 (Deducing environmentally conscious factors for apartment complex planning and weight evaluation)

  • 정숙진;서정범;윤성환
    • KIEAE Journal
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    • 제16권6호
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    • pp.51-56
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    • 2016
  • Purpose: As declines in the quality of residential environments occur, such as urban heat island effect, tropical night phenomenon, and violations of right to light and privacy due to urban densification and high rise building, these problems are emerging as social issues. In order to improve these issues, design factors which consider environmental aspects must be selected when planning apartment complexes, and ways to reflect them in the planning phase must be explored. Method: In this study, the analytical hierarchy process(AHP) was used to deduce design factors that considered environmental elements during the planning of apartment complexes. Furthermore, the priority and weight for each evaluation index were assessed. The objective was to propose a guideline for planning apartment complexes by finding the best solution for each evaluation index using complex weight values. Result: Floor area ratio was selected as the most important evaluation criterion in the environmentally conscious evaluation index for apartment complex planning. The shape and placement of skylights were selected as the most important evaluation criteria in the sunshine environment for a pleasant residential environment. Ground surface cover design was selected as the most important criterion in the outdoor thermal environment index for improving the microclimate within cities and apartment complexes. Thus, the results of this study can serve as an investigation guideline that concerns policy and regulations, and as reference data that can be used in planning apartment complexes.

HIGHT에 대한 부채널 분석 및 대응 방법 (Side Channel Attacks on HIGHT and Its Countermeasures)

  • 김태종;원유승;박진학;안현진;한동국
    • 정보보호학회논문지
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    • 제25권2호
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    • pp.457-465
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    • 2015
  • 사물인터넷은 다양한 장비에서 통신이 가능해야 한다. 사물인터넷 통신환경에서도 보안적인 요소를 고려해야하기 때문에 다양한 장비에 알맞은 암호 알고리즘이 필요하다. 그러므로 경량 블록 암호 알고리즘은 임베디드 플랫폼 사이에서 안전한 통신을 위하여 필수적이다. 그러나 이러한 환경에서 사용되는 경량블록알고리즘은 부채널 분석에 대한 취약점이 존재할 수 있다. 그렇기 때문에 부채널 대응기법을 고려하지 않을 수가 없다. 본 논문에서는 국산 경량암호 알고리즘인 ARX구조의 HIGHT 알고리즘에 대한 1차 전력분석 방법들을 제시하고 그 취약점을 확인한다. 또한, 1차 전력분석에 안전하도록 HIGHT를 설계하는 방법을 제안한다. 마지막으로, AES 와의 성능비교를 통하여 얼마나 효율성을 갖는지에 대해서 설명한다.

영국의 NHS 개혁 및 의료시장 동향에 관한 연구 (NHS Reforms and Healthcare Market in the United Kingdom)

  • 남은우;전기영
    • 한국병원경영학회지
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    • 제8권4호
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    • pp.1-25
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    • 2003
  • The wave of globalisation initiated by marketisation has increasingly penetrated into all sectors across the world, accordingly, the health & hospital service sector could not be made no escapes, and it currently faces the order of more marketised competition more than ever. Traditionally, the characteristic of the hospital services in the UK has considered as a model of social provision by government. However, contrary to our knowledge, the sphere of the hospital service in the UK has already been immersed in by the marketisation, in which the private actors have been embedded in order to tweak the activities of the hospital service with in the European Union. As the methodology of this research, the qualitative analysis, namely the interview with some doctors in Surgery, NHS Trusts staffs and relevant specialists in has been performed on April to May, 2003. And on the other hand, the various documents related to its service have been analysed. Thus, this paper will review the characteristics of the health service sector in the UK. In doing so, it will illuminate what would be the structural factors derived from its existing system, as a result, it will shed light on how the UK government makes an effort to resolve the problematic situation by reviewing the policy direction of Foundation Hospital proposed recently. In the next stage, it will analyse how all elements consist of the hospital management in the UK has been adjusted and be likely to be changed within Europe. More specifically focuses on how the private hospital service has been managed and related with the activities of its public hospital service-NHS Trusts. Also, under the circumstance, what private health insurance companies function will be studied. In conclusion, it will be concluded that what will be the implication of Korean hospital service market so as to correspond to globally open market by WTO. Now the UK health service system has faced a turning point of becoming more health care market internally and externally pressed by global and regional factors. Thus it is meaningful to scrutinize how a key part of social provision in the health care market system tends to adjust to globally marketised regulation.

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u-City 도시기반시절의 특성에 관한 연구 (A Study on the Characteristic of Ubiquitous Infrastructure for u-City)

  • 엄민경;송승민;김도년
    • 한국건설관리학회논문집
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    • 제12권5호
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    • pp.93-102
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    • 2011
  • 전 세계적으로 IT기술의 도시공간 적용이 도시 각 분야에서 추진되고 있으며, 특히 기반시설의 경우 도시의 기술적 대응의 중심적 역할을 수행하고 있다. 그러나 현재 u-City 기반시설을 기존 기반시설과 도시활동의 융합에 관한 고찰이 부족하고 실현가능한 기술을 중심으보 구축되어 중첩된 기술과 잦은 기기대체와 같은 난개발로 이어지고 있다. 이에 본 연구에서는 u-City 도시구성요소로서 기반시설의 특성에 주목하고 산업시대 기술의 국내 적용과정에서 도시기반시설의 공급과 주기를 비교 분석하여 국내 적용 시 시사점을 다루었다. 연구의 결과 첫째, 국내 u-City 기반시설의 공급은 도입기에 공공이 주도하여야 한다. 둘째, u-City 도시기반시설은 민첩한 성질이 요구되며, 이를 위해 세부요소의 규격화, 표준화가 필요하다. 셋째, IT기술과 기반시설의 융합에 따른 변화를 고려한 통합적 거시적 관점의 제도수립이 이루어져야 한다. 넷째, u-City 기반시설의 계획은 서비스, 디바이스, 시스템의 상호작용을 고려하여야 한다.

$PtCl_4$ 농도에 따른 염료감응형 태양전지의 효율 변화 (The Effect of $PtCl_4$ Concentration on Dye-Sensitized Solar Cell Efficiency)

  • 서현승;박미주;최은창;이성욱;김형진;홍병유
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.435-436
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    • 2008
  • Dye-sensitized Solar Cells(DSSCs) which convert incident sun light into electricity were expected to overcome global warming and depletion of fossil fuels. And it is one of study that is lately getting into the spotlight because manufacturing method is more simple and inexpensive than existing silicon solar cells. In this respect, DSSCs are in the limelight as the next generation solar cells. DSSCs are generally composed of a dye-modified $TiO_2$ photoelectrode, a Pt counter electrode, and an electrolytes containing a redox couple$(I^-/I_3^-)$. Among these elements, pt electrode were prepared by applying electric potential to FTO substrate in the $H_2PtCl_6$ solution. In this study, we report the solar cell efficiency depending on $PtCl_4$ concentration change. $PtCl_4$ concentration was 1mM, 5mM, 10mM, and 20mM, and adhered on FTO glass substrate by sintering process. When applied each $PtCl_4$ counter electrode on DSSC, the best efficiency was found at 10mM of $PtCl_4$ concentration. The catalyst promotes the movement of electron from the counter electrode to the electrolyte the higher the molarity, the better the efficiency. However, in case of 20mM, it is estimated that over-deposited $PtCl_4$ tends to restrict the movement of electron due to its bundle formation.

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수종 치과용 자석유지장치의 부식저항성에 대한 전기화학적 연구 (THE ELECTROCHEMICAL STUDY ON CORROSION RESISTANCE OF VARIOUS DENIAL MAGNETIC ATTACHMENTS)

  • 손병섭;장익태;허성주;곽재영
    • 대한치과보철학회지
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    • 제39권4호
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    • pp.336-350
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    • 2001
  • The purpose of this study was to investigate corrosion tendency and to compare corrosion resistance of three dental magnetic attachments and its keeper alloy by coercive, electrochemical method. By using petentiodynamic polarization technique, magnetic elements and its keeper alloy of Magfit EX600 system(MF, MFK), Dyna ES regular system(DN, DNK) and Shiner SR magnet system(SR, SRK) were corroded electrochemically in 0.9% NaCl electrolytic solution. Open-circuit potential and anodic polarization curve was measured with Potentiostat(model 273 EG&E) and polarization curve was created by current density per square area following scanning of increased series of voltage in the rate of 1.0mV per second. Before and after electrochemical corrosion, the surface roughness test was done. Thereafter the change of mean surface roughness value(Ra) and mean peak value(Rt) of surface roughness was compared one another. In order to observe the corroded surface of each specimen, metallurgical light microscopic(${\times}37.5$) and scanning electron microscopic view(SEM ${\times}100$) was taken and compared one another. Conclusion is followings. 1. All of six covering metal of dental magnetic attachments and its keeper alloy were corroded in various degree after electrochemical corrosion. 2. The corrosion resistance of which used in this experiment is the following in high order; DNK, MFK, DN, MF, SRK and SR. 3. Especially Shiner magnet system and its keeper alloy were more severely corroded after electrochemical corrosion and the change of Ra Rt value were more increased than others. 4 Metallurgical and scanning electron microscopic view showed the pitting corrosion tendency of all experimental alloy but DNK and SR. 5. Covering metal of magnet was more corroded than its keeper alloy.

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공중 회전 방향탐지 반사판 안테나 급전기용 초광대역 LPDA 안테나 설계 (Design of an Ultra-Wideband LPDA Antenna for the Feeder of an Airborne Spinning Direction-Finding Reflector Antenna)

  • 박영주;박동철
    • 한국전자파학회논문지
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    • 제27권7호
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    • pp.653-659
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    • 2016
  • 본 논문은 공중에서 회전하면서 광대역 신호를 방향 탐지하고 수신하는 반사판 안테나 급전기용 초광대역 LPDA(Log-Periodic Dipole Array) 안테나를 제안한다. S 대역부터 Ka 대역까지 20:1 이상의 초광대역 특성을 확보하기 위해 평면기판 위에 방사소자를 인쇄하였고, 기판 사이에 견고한 구조의 쐐기형 유전체 지지대를 삽입하였다. 또한, 무게를 줄이기 위해 지지대 중심 부분을 스티로폼 재질로 대체하였다. 설계된 LPDA 안테나의 5-dB 반사손실 대역폭은 시뮬레이션 37.57:1(1.09~40.95 GHz), 측정 33.85:1(1.31~44.35 GHz)로 초광대역 특성을 나타내었다. 동작 대역에서 평균 이득은 시뮬레이션, 측정 각각 5.79 dBi, 5.76 dBi로서 요구하는 이득을 확보하였다. 제안된 견고하고 가벼운 초광대역 LPDA 안테나는 항공용으로 적용될 수 있음을 확인하였다.

보들레르의 미적 관점에 의한 예술과 패션디자인 (Art and Fashion Design Based on Charles Baudelaire's Aesthetic Perspective)

  • 김영선;금기숙
    • 복식
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    • 제58권1호
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    • pp.17-32
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    • 2008
  • This study focuses on the analysis of Baudelaire's aesthetic perspective which has established a theoretical basis on research of the critical reviews' salon exhibitions as written by Baudelaire. Charles Pierre Baudelaire(1821-1867) having lived during the latter part of Neo-classicism and the era of Romanticism and Impressionism, Baudelaire displayed opposition to customary realities such as social ideology or religious authority that suppressed human nature. Also he pioneered a new genre known as art criticism and wrote much that provided important insights on the essential elements of artistic work, modernity and trend, as well as art definition and art categories. The aesthetic perspective and creative spirit were formed by Baudelaire, during his age were also reconfirmed in the successive ages of modernism and postmodernism. As such, this study sheds light on how Baudelaire's aesthetic perspective was not only temporarily assertion but it is consistently applied to modern art and fashion area. What is more important that, Baudelaire admired new artificial beauty that is created by the human soul liberated from natural instincts or desires. Especially, informed by strangeness and distinctiveness, Baudelaire's view of fashion ran along the same vein as his view of art, and these views form the basis of that creative spirit which situated western fashion on a center of the world. In conclusion, the research on Baudelaire's aesthetic perspective will reaffirm a firm awareness of the creative spirit essential to globally-oriented creative artists and designers who work within the circumstance of the 21st century, a time when the paving of new aesthetic paths is necessary. The research also offers a clear understanding of the aesthetic values demanded by this age.