• 제목/요약/키워드: protection effect

검색결과 2,985건 처리시간 0.041초

Neutron Dosimetry and Monitoring in the Radiation Environment

  • Nakamura, Takashi
    • Journal of Radiation Protection and Research
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    • 제14권2호
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    • pp.51-62
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    • 1989
  • The high efficiency moderated-type neutron spectrometer and doseequivalent counter were developed for the measurement of low level environmental neutrons. By using these detectors, the neutron energy spectra and dose equivalent rates due to skyshine effect were measured in the environment surrounding the accelerator facilities and also the altitude variation of cosmic ray neutrons in the aircraft flying over Japan.

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조사연구-분진폭발에 대한 소고

  • 이지섭
    • 방재기술
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    • 통권19호
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    • pp.29-35
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    • 1995
  • This decument, translated and rearranged deseribes the features of dust explosion and the factors which have an important effect upon the hazard of dust explosion on the purpose of prevention the disaster caused by dust explosion. The dust explosion exist close to our common life as latently, but it seems to be overlooking in com-mon, regretably Tr need to be evoked.

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차량 COWL구조에 따른 보행자 머리 상해치 영향에 관한 연구 (A study on effect of pedestrian head injury with vehicle cowl structure type)

  • 홍규갑;정호영;조원철;이태식
    • 한국방재학회:학술대회논문집
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    • 한국방재학회 2008년도 정기총회 및 학술발표대회
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    • pp.517-519
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    • 2008
  • 2007, Pedestrian protection test is operated by Korea ministry of construction & transportation. This paper focused on small size vehicle cowl structure type for reducing pedestrian head injury.

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전력용 피뢰기의 임펄스에 의한 파손과 대척 기술 (Fracture and Protection Technologies against Impulse of Power Arresters)

  • 한세원;조한구;김석수
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.190-193
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    • 2001
  • ZnO varistors have been widely used to protect power system and electronic system against overvoltages based on their excellent nonlinearity. In order to increase their protection capability, the fracture and protection technologies of arresters have to study according to their applications, namely ImA DC voltage, leakage currents, impulse residual voltages, withstanding capability to impulse surge, and energy absorption capability. ZnO varistors which have nonlinear current-voltage characteristic name a number of failure mechanism when ZnO elements absorb surge energies. Failure mode by thermal stress and Pin hole are among the most common failure mechanism at the high current surge current. In this study, the fracture mechaism of power arresters are introduced and protection technologies are researched. In particular the effect of thermal stress by surge currents to ZnO elements and methods against arc surge energy through withstand structure design of arrester are discussed.

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디지털 원자로보호계통 불가용도 평가 (An Unavailability Evaluation for a Digital Reactor Protection System)

  • 이동영;최종균;김지영;유준
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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    • pp.81-83
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    • 2005
  • The Reactor Protection System (RPS) is a very important system in a nuclear power plant because the system shuts down the reactor to maintain the reactor core integrity and the reactor coolant system pressure boundary if the plant conditions approach the specified safety limits. This paper describes the unavailability assessment of a digital reactor protection system using the fault tree analysis technique. The fault tree technique can be expressed in terms of combinations of the basic event failures. In this paper, a prediction method of the hardware failure rate is suggested for a digital reactor protection system. and applied to the reactor protection system being developed in Korea.

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부식촉진시험에 의한 콘크리트 내의 철근의 부식특성에 관한 실험적 연구 (An Experimental Study on the Corrosion Characteristics of Reinforcing Steel in Concrete by the Accelerated Corrosion Test)

  • 배수호;정영수;김년산;권영우;권혁진
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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    • pp.503-507
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    • 2000
  • The corrosion protection methods of reinforcing steel in concrete are the various methods such as increasing thickness of cover concrete, using of reinforcing bars coated with epoxy, dosage of corrosion inhibitor as concrete admixture, cathodic protection method and etc. In this study, the performance of corrosion protection was investigated for the test specimens using corrosion inhibitors and cathodic protection, respectively. For this purpose, the accelerated corrosion tests for reinforcing steel were conducted according to the periodic cycles(140 days) of wetting($65^{\circ}C$, 90% R.H) and drying period($15^{\circ}C$, 65% R.H) for the test specimens. As a result, it can be concluded from the test that the effect of corrosion inhibitor was found to be variable with products, the cathodic protection method was found to be independent of salt concentration in concrete.

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Setting Considerations of Distance Relay for Transmission Line with STATCOM

  • Zhang, Wen-Hao;Lee, Seung-Jae;Choi, Myeon-Song
    • Journal of Electrical Engineering and Technology
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    • 제5권4호
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    • pp.522-529
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    • 2010
  • Distance relay plays an important role in the protection of transmission lines. The application of flexible AC transmission systems (FACTS) devices, such as the static synchronous compensator (STATCOM), could affect the performance of the distance relay because of compensation effect. This paper analyzes the application of distance relay on the protection of a transmission line containing STATCOM. New setting principles for different protection zones are proposed based on this analysis. A typical 500 kV transmission system employing STATCOM is modeled using Matlab/Simulink. The impact of STATCOM on distance protection scheme is studied for different fault types, fault locations, and system configurations. Based on simulation results, the performance of distance relay is evaluated. The setting principle can be verified for the transmission line with STATCOM.

희생양극식 음극방식이 적용된 해안 교량 구조물의 방식거동 (Cathodic Protection Behavior of Coastal Bridge Structure with Sacrificial Anode Cathodic Protection System)

  • 하지명;진충국;정진아
    • Corrosion Science and Technology
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    • 제11권6호
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    • pp.242-246
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    • 2012
  • This measurement represents the effectiveness of sacrificial anode cathodic protection (SACP) system in a coastal bridge structure. To verify the cathodic protection (CP) effect, the monitoring sensor (DMS-100) that could measure potential, corrosion rate, current, concrete resistivity, and temperature was embedded. The measurement conducted for three years after CP system was installed. Specifically, due to the fact that fresh water and sea water was repeated in the bridge structure, this bridge structure presented special CP behavior. Measurement factors were CP potential, CP current, concrete resistivity, and depolarization potential. In addition, visual inspection was also carried out. As a result of current and depolarization measurement, CP system was well activated in most piers.

DNA Damage Protection and Anti-inflammatory Activity of Different Solvent Fractions from Aruncus dioicus var. kamtschaticus

  • Zhang, Qin;Kim, Hye-Young
    • 한국자원식물학회지
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    • 제27권6호
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    • pp.714-719
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    • 2014
  • This study investigated DNA damage protection and anti-inflammatory activity of different solvent fractions from Aruncus dioicus var. kamtschaticus (A. dioicus) aerial parts water extract. As for DNA damage protection, distilled water ($H_2O$) fraction displayed the most powerful protection for DNA damage at a concentration of 1 mg/ml. As for anti-inflammatory activity, dichloromethane ($CH_2Cl_2$) fraction exhibited the highest NO inhibition activity, ranging from 61% to 19% ($10-40{\mu}g/ml$). Furthermore, the levels of pro-inflammatory cytokines mRNA expressions and intracellular reactive oxygen species (ROS) were employed to verify the anti-inflammatory activity of the $CH_2Cl_2$ fraction on further researches. It could be concluded that A. dioicus had a significantly effect of DNA damage protection and anti-inflammatory activity which also as an essential edible vegetable and medicinal species.