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Effect of a Series Connection of a Bi-Electrolyte Hydrogen Sensor in a Leak Detector

  • Han, Hyeuk Jin;Park, Chong Ook;Hong, Youngkyu;Kim, Jong Suk;Yang, Jeong Woo;Kim, Yoon Seo
    • Journal of Sensor Science and Technology
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    • v.24 no.1
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    • pp.6-9
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    • 2015
  • Conventional leak detectors are widely based on helium gas sensors. However, the usage of hydrogen sensors in leak detectors has increased because of the high prices of helium leak detectors and the dearth in the supply of helium gas. In this study, a hydrogen leak detector was developed using solid-state hydrogen sensors. The hydrogen sensors are based on Park-Rapp probes with heterojunctions made by oxygen-ion conducting Yttria-stabilized zirconia and proton-conducting In-doped $CaZrO_3$. The hydrogen sensors were used for determining the potential difference between air and air balanced 5 ppm of $H_2$. Even though the Park-Rapp probe shows an excellent selectivity for hydrogen, the sensitivity of the sensor was low because of the low concentration of hydrogen, and the oxygen on the surface of the sensor. In order to increase the sensitivity of the sensor, the sensors were connected in series by Pt wires to increase the potential difference. The sensors were tested at temperatures ranging from $500-600^{\circ}C$.

Comparison of multi-channel terrestrial broadcasting service method (지상파 다채널방송 서비스 방식 비교 연구 (MMS와 Korea-View 방식을 중심으로))

  • Park, Jong-Won;Park, Sung Kyu;Lee, Chang-Hyung;Kim, Gwang-Ho;Park, Goo-Man
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2011.07a
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    • pp.50-52
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    • 2011
  • 지상파 디지털방송 표준인 미국의 ATSC 서비스가 진화를 하고 있다. 2006년 한국방송협회는 독일 월드컵 방송당시 지상파 다채널방송인 MMS(Multi-Mode-Service) 시험방송을 실시하였다. MMS 시험방송은 화질열화 및 수신기 오동작 논란으로 중단되었고 KBS는 2009년부터 다채널이 가능한 코리아뷰(Korea-View) 방송을 준비하고 있다. 코리아뷰의 압축방식은 MPEG-2와 MPEG-4를 혼합한 방식으로 미국의 모바일방송 표준(A/153)과 동일한 방식이다. 이번 논문에서는 MMS, 코리아 뷰의 지상파 다채널방송 서비스에 대한 기술적 특징과 차이를 분석하고 향후 서비스 도입에 따른 정책적 방향을 제시하였다.

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Amoeba: A Medeiator System for XML Data ana Relational Databases (Amoeba: XML 데이터와 관계형 데이터베이스를 위한 미디에이터 시스템)

  • Park, Kyoung-Hyun;Park, Sung-Hee;Park, Jeong-Seok;Ryu, Keun-Ho
    • Annual Conference of KIPS
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    • 2000.10a
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    • pp.101-104
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    • 2000
  • XML이 인터넷을 기반으로 하는 정보교환의 매개체로써 다양한 응용분야로 확산됨에 따라 XML 데이터로부터 구조정보를 추출하고 효율적으로 저장하며 관계형 데이터베이스로부터 추출된 데이터를 XML 문서로 생성하는 시스템이 요구되어진다. 기존의 관계형 데이터베이스 벤더들이 XML을 처리하기 위해 시스템을 확장하기는 하지만 이러한 시스템들은 시스템과 플랫폼에 종속적이라는 단점을 가지고 있다. 이 논문에서는 이러한 문제점을 해결함과 동시에 DTD와 관계형 스키마가 존재하지 않는 환경에서 XML문서를 효율적으로 저장하고 XML_QL을 지원하는 Amoeba 시스템을 소개한다.

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CHEMOPREVENTIVE EFFECTS IN MOUSE SKIN CARCINOGENESIS AND INDUCTION OF APOPTOSIS IN HUMAN PROMYELOCYTIC LEUKEMIA(HL-60) CELLS BY XANTHORRHIZOL

  • Kim, Heui-og;Chung, Won-Yoon;Park, Min-Ah;Kim, Mi-Jeong;Park, Jae-Hee;Park, Kwang-Kyun
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2001.10a
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    • pp.141-142
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    • 2001
  • Curcuma xanthorrhiza Roxb(Zingiberaceae) has been traditionally used in Indonesia for dietry and medicinal purposes. Xanthorrhizol is a sesquiterpenoid isolated from C. xanthorrhiza that has been known to possess anti-inflammatory and anticarcinogenic defects.(omitted)

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Effect of Recombinant Bovine Somatotropin (${\gamma}$ bST) Administration on bST Levels in Milk of Cows

  • Park, Jeongeun;Park, Myung-Ja;Jaeho Chin;Park, Jongsei;Kim, Jooho
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1995.04a
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    • pp.127-127
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    • 1995
  • The present study was conducted to examine the effect of recombinant bovine somatotropin(${\gamma}$ bST), which was administered to cow to promote milk production, on bST levels in milk. Fourteen cows were divided into two groups: 1) control cows received neither y bST nor vehicle, 2) treated cows were administered twice at two-week interval with 500mg ${\gamma}$ bST each cow by subcutaneous injection. Milk samples were taken on day 0 (prior to injection), day 7 (7 days after 1st injection), day 21 (7 days after 2nd injection) and day 35 (21 days after 2nd injection).

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The frequency utilization research for the terrestrial broadcasting direct received environment construction and next generation broadcasting (지상파방송 직접수신 환경 구축과 차세대방송을 위한 주파수 활용 연구)

  • Park, Sungkyu;Lee, Changhung;Park, Jongwon;Kim, Gwangho;Park, Gooman
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2011.11a
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    • pp.27-30
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    • 2011
  • 본 논문에서는 방송용주파수를 좀 더 효율적으로 활용하여 시청자가 쉽게 지상파방송을 직접 수신할 수 있도록 DTV 방송 수신환경 개선 방법에 대해 찾아보고 난시청해소와 차세대방송에 필요한 주파수 소요량을 정량적으로 제시하고자 한다. 특히 디지털전환 이후에 회수되는 700MHz 대역 (108MHz 주파수폭)에 대하여 UDTV 와 Full-HD 3DTV 기술을 적용한 차세대방송을 구축할 때 난시청해소와 시청자와 방송과 산업에 미치는 효과를 제시한다.

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Long-Term Monitoring of the Barrier Effect of the Wild Boar Fence

  • Lim, Sang Jin;Kwon, Ji Hyun;Namgung, Hun;Park, Joong Yeol;Kim, Eui Kyeong;Park, Yung Chul
    • Journal of Forest and Environmental Science
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    • v.38 no.2
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    • pp.128-132
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    • 2022
  • Wild boars (Sus scrofa) not only cause crop damage and human casualties, but also facilitate the spread of many infectious diseases in domestic animals and humans. To determine the efficiency of a fencing system in blocking the movement of wild boars, long-term monitoring was performed in a fenced area in Bukhansan National Park using camera traps. Upon monitoring for a period of 46 months, there was a 72.6% reduction in the number of wild boar appearances in the fence-enclosed area, compared to that in the unenclosed area. For 20 months after the fence installation, the blocking effect of the fence was effective enough to reduce the appearance of wild boars by 92.6% in the fence-enclosed area, compared to that in the unenclosed area. The blocking effect of the fence remained effective for 20 months after its installation, after which its effectiveness decreased. Maintaining a fence for a long time is likely to lead to habitat fragmentation. It can also block the movement of other wild animals, including the endangered species - the long-tailed goral. This study suggests a 20-month retention period for the fences installed to inhibit the movement of wild boars in wide forests such as Gangwon-do in South Korea. To identify how long the blocking effect of the fences lasts, further studies are needed focusing on the length and height of the fence, and the conditions of the ground surface.