• 제목/요약/키워드: state standards

검색결과 770건 처리시간 0.033초

감전사고 예방을 위한 영국의 보호도체 적용 방법 (The Application Method of a Protection Conductor for the Prevention of Electric Shock in England)

  • 정진수;정종욱;한운기;이준
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 제39회 하계학술대회
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    • pp.2216-2217
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    • 2008
  • This paper write about earth system for the prevention electric shock and a protection of equipment in england. The IEC60364 and BSI(British Standards Institution) define earthing method(IT, TT, TN-C, TN-S, TN-C-S)-BSI is british standards and in case of england almost use the TN system. TN system can classify TN-S & TN-C-S(PME). The findings on survey in england are used the TN-S system and TN-C-S system about 70% and residue 30% are used TT system and IT system from the exiting state of things.

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Terahertz time-domain transmission and reflection spectroscopy of niobium

  • Hong, Taeyoon;Choi, Kyujin;Park, Byoung-Cheol;Ha, Taewoo;Sim, Kyung Ik;Ha, Dong-Gwang;Chong, Yonuk;Kim, Jae Hoon
    • 한국초전도ㆍ저온공학회논문지
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    • 제15권1호
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    • pp.11-13
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    • 2013
  • We have developed a terahertz time-domain spectroscopy (THz-TDS) system for transmission and reflection measurements of metallic thin films. Using our THz-TDS system, we studied the conventional superconductor niobium (Nb) in the normal state in the spectral range from 5 to $50cm^{-1}$. Both the real and imaginary parts of the conductivity are acquired without Kramers-Kronig analysis. Nb exhibits a nearly frequency independent real conductivity spectrum in the terahertz range, with a very small imaginary part.

건설공사 유지보수품셈 사례조사 연구 (Case Study on the Construction Standard Production Rate for Operation and Maintenance Technology)

  • 안방율;박태일
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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    • pp.250-251
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    • 2019
  • Lots of infrastructures have been newly constructed through the rapid economic growth of 1970's. Since the infrastructures has mostly deteriorated and this circumstance makes the need for maintenance and rehabilitation(M&R) of infrastructures to obtain the convenience and safety of users even more essential. Although markets for M&R project become larger, the construction standards for cost estimation of M&R work are insufficient. Thus, the purpose of this study is to examine the present state of standards for cost estimation of M&R works using case studies. Finally, this work could be utilized as the basis for the development of national standard for estimation of M&R work.

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Collapse of Charge Ordering in Ru-doped Mono-layered Manganites

  • Hong, Chang-Seop;Kim, Wan-Seop;Hur, Nam-Hwi
    • Journal of Magnetics
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    • 제8권2호
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    • pp.85-88
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    • 2003
  • The magnetic and transport properties far single crystals of Ru-doped mono-layered manganites $La_{0.5}Sr_{1.5}-Mn_{1-x}Ru_xO_4$ (0$\leq$$\chi$$\leq$0.1) have been studied using neutron diffraction and magnetization measurements. Temperature dependent magnetization data reveal that with an increase in the Ru concentration the parent charge ordered antiferromagnetic state is gradually destroyed and new ferromagnetic phase evolves. In the low Ru-doped system spin glass behavior is apparent in low temperature region, which is confirmed by ac and do magnetization measurements. The competing magnetic interaction between Mn/Mn and Mn/Ru couples is the most likely cause of the spin glass transition.

The Pacing of Volume Lessons in American Elementary Textbooks Compared to Students' Development in Volume Measurement

  • Hong, Dae S.;Choi, Kyong Mi;Hwang, Jihyun;Runnalls, Cristina
    • 한국수학교육학회지시리즈D:수학교육연구
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    • 제24권2호
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    • pp.83-109
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    • 2021
  • In the early stage of lesson enactment process, teachers use textbooks and other resources to select tasks and activities. It follows that discrepancies between textbooks and research-recommended pathways for learning may lead to concerns or issues with pacing in the classroom. To explore this idea further, this study examined the alignment between three popular standards-aligned textbooks series and volume learning trajectories. The results indicated that the standards-based textbooks examined may lack attention to important topics in the pacing of volume instruction, and suggest the need to inform both pre-service and in-service teachers about the gap between textbook lessons and volume learning trajectories so that they will be able to reflect students' thinking in volume learning trajectory to their lessons.

Fungal Biotransformation of Monoterpenes Found in Agro-Industrial Residues from Orange and Pulp Industries into Aroma Compounds: Screening Using Solid Phase Microextraction

  • Junior, Mario Roberto Marostica;Mota, Natasha Onoyama;Baudet, Nathalie;Pastore, Glaucia Maria
    • Food Science and Biotechnology
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    • 제16권1호
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    • pp.37-42
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    • 2007
  • The biotransformation of monoterpenic agro-industrial wastes (turpentine oil and essential orange oil) was studied. More than 40 fungal strains were isolated from Brazilian tropical fruits and eucalyptus trees and screened for biotransformation of the waste substrates. Solid phase microextraction was used to monitor the presence of volatile compounds in the headspaces of sporulated surface cultures. The selected strains were submitted to submerged liquid culture. The biotransformation of R-(+)-limonene and ${\alpha},\;{\beta}-$ pinenes from the oils resulted in ${\alpha}-terpineol$ and perillyl alcohol, and verbenol and verbenone, respectively, as the main products. The selected strains were also placed in contact with ${\alpha}-$ and ${\beta}-$ pinenes standards. It was confirmed that verbenol, verbenone, and ${\alpha}-terpineol$ were biotransformation products from the terpenes. A concentration of 90 mg/L of verbenone was achieved by Penicillium sp. 2360 after 3 days of biotransformation.

Listed Local State-Owned Enterprises and Environmental Performance: Evidence from China

  • TANG, Kai;BAE, Khee Su
    • The Journal of Asian Finance, Economics and Business
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    • 제8권2호
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    • pp.255-262
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    • 2021
  • The paper examines the influence of ownership type on environmental performance of Chinese listed enterprises. China's environmental problems are attributed to the collusion between enterprises and economy-oriented local governments, which has allowed many companies to skirt environmental regulations. Especially, local state-owned enterprises (SOEs) tend to have worse environmental performance than private firms, under the wing of local governments, with whom they have a closer political connection. According to the report of the Environmental Protection Agency, currently the unacceptably poor environmental performance of local SOEs has severely hampered the realization of green economy in China. After examining the dataset of 15,996 firm-year observations from 2,688 listed firms, this paper found that, in the presence of central government supervision and personnel intervention, listed local SOEs will be forced to improve their environmental performance in accordance with standards set by the central government, which leads to better environmental performance than that of listed private firms (private firms). The result of two-stage regression also supports the conclusion. This shows increased supervision and personnel intervention from the central government can significantly improve the environmental performance of local SOEs. The research in this paper expects to make a contribution to attaining the goal of green economy in China.

EPR 측정에 의한 CaMgSi2O6:Eu2+ 형광체의 열적 안정성 연구 (Thermal Stability of CaMgSi2O6:Eu2+ Phosphor by EPR Measurement)

  • 허경찬;김용일;유권상;문병기
    • 한국자기학회지
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    • 제15권4호
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    • pp.246-249
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    • 2005
  • 플라즈마 디스플레이(Plasma Display Panel: PDP)용 청색 형광체인 $CaMgSi_{2}O_6:Eu^{2+}(CMS:Eu^{2+})$를 고상반응(sold-state reaction)법으로 합성하였다. 합성한 재료를 실온에서부터 $1,100^{\circ}C$까지 열처리하여 photoluminescence(PL)와 EPR 측정으로 열적 안정성을 연구하였다. $CMS:Eu^{2+}$ 형광체를 대기 분위기 하에서 상온에서부터 $700^{\circ}C$까지 열처리하였을 때 PL의 변화는 없었으나, $700^{\circ}C$ 이상의 온도에서 열처리 하였을 때는 PL의 감소를 나타내었다. $700^{\circ}C$까지 PL의 안정된 거동을 보이는 것은 구조적으로 안정된 12 면체를 하고 있는 $Ca^{2+}$ 이온의 일부를 $Eu^{2+}$ 이온이 점유하고 있어 $Eu^{2+}$의 원자가 변화에 영향을 미치지 못했으나, $700^{\circ}C$이상의 PL의 감소는 $Eu^{2+}$에서 $Eu^{3+}$의 산화에 의한 것이라는 것을 EPR 흡수세기의 변화로부터 알 수 있었다.

도로교설계기준 한계상태설계법을 적용한 RC슬래브교의 상대 안전도 평가 (Evaluation for Relative Safety of RC Slab Bridge of Applying Limit State Design Code on Korean Highway Bridge)

  • 박진우;황훈희;강신오;조경식;박우진
    • 한국안전학회지
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    • 제28권5호
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    • pp.41-48
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    • 2013
  • This paper is intended to provide the background information and justification for Korean highway bridge design code(limit state design)(2012). Limit state design method calculates reliability index and probability of failure through the analysis of the reliability of the experimental database. It has become possible to perform the economical and consistent design by evaluating the safety of a structure quantitatively. In this paper, we used the design specifications of RC slab bridge of superstructure form of Road Design Manual in Part 5 bridge built in highway bridge. This study conducted structural analysis using the method of frame structure theory, design and analysis of bridge by limit state design method, the design code including various standards and Load model applied Korean highway bridge design code limit state design(KHBDC;2012). As a result, it analyzed the effect of safety through comparison. Showing effect of improvement the safety factor and comparing the value of the result, it is determined to be capable of economical design and safety. Furthermore, limit state design method was able to determine many redundant force of cross-section compared with existing design method. It is determined that it can reduce the overall amount because of the reduction of the cross-section and girder depth.

원자력발전소 화재방호와 소방시설 기술기준 적용에 대한 고찰 (A Study on Fire Protection in Nuclear Power Plants and Application of the Code and Standards for Fire Protection Systems)

  • 김위경;정기신
    • 한국화재소방학회논문지
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    • 제26권6호
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    • pp.38-44
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    • 2012
  • 원자력발전소 화재방호의 목표는 화재 시 원자로의 안전정지 상태를 유지하여 환경으로의 방사성물질 누출을 최소화하며, 종사자 인명안전 및 재산을 보호하는데 있다. 소방시설은 발생된 화재를 조기 감지 및 진압하여 화재로 인한 피해를 완화시킬 수 있는 심층방어개념에 입각한 중요한 방어수단의 하나이다. 그러나 소방방재청에서 제시하고 있는 소방시설 설치기준이 원자력발전소에 특화되어 있지 않아 인허가 시 별도의 심의 절차가 요구되고 있다. 또한, 성능위주설계와 같은 규정은 작업자의 인구밀도가 비교적 낮은 원자력발전소에 적용하는데 어려움이 있다. 이 논문에서는 원전 화재방호와 관련된 법령의 상세 검토를 통하여 도출된 근본적인 문제점과 KEPIC FPN의 국내 원전 적용성에 대한 평가를 통하여 소방시설에 대한 기술기준에 대한 개선방향을 제시하였다.