• 제목/요약/키워드: DO-254

검색결과 183건 처리시간 0.025초

Clark전극에 의한 DO 농도측정을 위한 절전형 센서개발에 관한 연구 (Development of low power type sensor for the DO concentration measurement by clark electrode)

  • 이동희
    • E2M - 전기 전자와 첨단 소재
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    • 제8권3호
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    • pp.254-260
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    • 1995
  • A method is described for the design and fabrication of the sensor interface circuits on the Clark electrodes for the dissolved oxygen(DO). The discussion includes a method for the +5 V single-supply driving for the sensor circuits, which has low power comsumption for the front-end electronics. DO probe under test is composed of the Clark electrode with silver anode, gold cathode and the electrolyte of half saturated KCI solution and the FEP teflon memtrance for the oxygen penetration. Typical polarograms for the DO probes by using this sensor circuit reveals high accuracy over 99% of the I to V conversion. Partial pressure of oxygen obtained from the polarograms are well suited to the results calculated. It is expected that the proposed sensor circuits can be utilized into the customized IC for the battery-driven small-size DO meters.

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Sclerotium rolfsii에 의한 설악초 흰비단병 (Stem Rot of Euphorbia marginata Caused by Sclerotium rolfsii)

  • 권진혁;강동완;김민근
    • 한국균학회지
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    • 제39권3호
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    • pp.254-255
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    • 2011
  • 경상남도농업기술원 화단에서 S. rolfsii에 의한 설악초 흰비단병이 발생되었다. 병징은 줄기가 수침상으로 물러지고 썩으면서 서서히 시들어 말라 죽었다. 병든 줄기와 지제부, 토양 표면에 흰색의 곰팡이가 발생하고 갈색의 작은 둥근균핵을 많이 형성하였다. 균핵의 크기는 1~3mm이며 균사의 폭은 4~9 ${\mu}m$였다. 균사특유의 clamp connection이 관찰되었다. 균사생육과 균핵형성 적온은 $30^{\circ}C$이었다. 설악초에서 발생한 병징과 병원균의 균학적 특징을 조사한 결과, 이 병을 Sclerotium rolfsii Saccardo에 의한 설악초 흰비단병으로 명명하고자 제안한다.

소셜미디어와 PDM 시스템을 활용한 협업적 제품자료관리 교육 (Education of Collaborative Product Data Management by Using Social Media in a Product Data Management System)

  • 도남철
    • 한국CDE학회논문집
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    • 제20권3호
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    • pp.254-262
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    • 2015
  • This study proposes an approach to Product Data Management (PDM) education for collaborative product data management, which can support collaborative product development process. This approach introduces social media and a PDM system into a framework for PDM education supported by consistent product development process and product data model. It has been applied to two PDM classes and the result shows that the social media in PDM education can support not only experiences of the collaborative product data management but also interactive and informal communications among instructors and participants using integrated social media with product data during courses.

증령에 따른 치고졸의 변화에 관한 방사선학적 연구(I) (Radiographic Study of the Alveolar Bone Changes with Aging)

  • 김영구
    • Journal of Oral Medicine and Pain
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    • 제8권1호
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    • pp.77-82
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    • 1983
  • The author measured the degree of alveolar bone resorption around mandibular central incisors in Korean female(254). Mandibulr central incisors were selected from the females who do not have periodontal disease or malocclusion. The selected radiograms were enlarged in the $5"\times7"$ printing papers for the precise measuring. The obtained results were as follows : 1. The average alveolar bone resorption around mandibular central incisors in Korean women were 1.91mm in 3rd decade, 2, 16mm in 4th decade, 2.51mm in 5th deacade, 2.70mm in 6th decade, 2.94mm in older age group. 2. Alveolar bone resorption and age were in positive correlation; there is a tendency that the alveolar bone resorption increase with aging. 3. The regression equation is as follows. Y=13.57x + 7.06(r=0.60, n=254) (Y=estimated age, x=Length(C-E Junction alveolar crest)lar crest)

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Vibration Analysis of a Rotor considering Nonlinear Reaction of Hydrodynamic Bearing

  • Lee, Soo-Mok;Lim, Do-Hyeong;Bae, Jong-Gug;Yang, Bo-Suk
    • International Journal of Fluid Machinery and Systems
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    • 제2권3호
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    • pp.254-259
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    • 2009
  • In this paper it was attempted to treat the hydrodynamic journal bearing as a time-based nonlinear reaction source in each step of rotor rotation in order to observe the bearing effect more realistically and accurately in stead of the conventional method of simple linearized stiffness and damping. Lubrication analysis based on finite element method is employed to calculate the hydrodynamic reaction of bearing and Newmark's method was used to calculate the rotor dynamics in the time domain. Simulation for an industrial electrical motor showed remarkable results with differences compared to those by the conventional method in the dynamic behavior of the rotor.