• 제목/요약/키워드: V.A.K.

검색결과 24,951건 처리시간 0.053초

A study for Decision Method of Human Body Safety according to Power Load Fluctuation of the Chechon Area (제천지역 전력부하변동에 따른 인체 전 판단 방법에 대한 연구)

  • 김상철;김두현
    • Journal of the Korean Society of Safety
    • /
    • 제15권4호
    • /
    • pp.69-77
    • /
    • 2000
  • This paper presents a study for decision method of human body safety according to power load fluctuation of the Chechon area. To cope with substantial electromagnetics analysis, the safety assessments were analyzed the double 154 [kV] T/L, 345 [kV] T/L, Chechon-Ichon, Chechon-Youngju, respectively. As the results of case study, in case of 345 [kV] T/L, the electric field value was 11.4927 [kV/m], magnetic field value was 0.4622 [G] at the point about 7 [m] away from the line in severest case. The results showed that the membership of a proposition fuzzy '11.4937 [kV/m] is hazardous' is 0.7063 for the severest case in case of 345 [kV] T/L. As the analytic results using the fuzzy qualifier term, the membership in case of very false is 0.0862 and fairly false is 0.5419, respectively.

  • PDF

Protection system for the application of 22.9 kV HTS cable and FCL to real power grid in Korea (국내 실계통에서의 22.9 kV 초전도케이블/한류기 시범적용을 위한 보호시스템 설계)

  • Lee, Seung-Ryul;Yoon, Jae-Young;Yang, Byong-Mo
    • Progress in Superconductivity and Cryogenics
    • /
    • 제12권3호
    • /
    • pp.25-28
    • /
    • 2010
  • 22.9 kV HTS cable and FCL will be installed in 154 kV Icheon substation. It is necessary to design a protection system of the substation for a successful application of the HTS devices. This paper proposes a new power protection system for the application of 22.9 kV HTS cable and SFCL to 154 kV Icheon substation in Korea.

On Diameter, Cyclomatic Number and Inverse Degree of Chemical Graphs

  • Sharafdini, Reza;Ghalavand, Ali;Ashrafi, Ali Reza
    • Kyungpook Mathematical Journal
    • /
    • 제60권3호
    • /
    • pp.467-475
    • /
    • 2020
  • Let G be a chemical graph with vertex set {v1, v1, …, vn} and degree sequence d(G) = (degG(v1), degG(v2), …, degG(vn)). The inverse degree, R(G) of G is defined as $R(G)={\sum{_{i=1}^{n}}}\;{\frac{1}{deg_G(v_i)}}$. The cyclomatic number of G is defined as γ = m - n + k, where m, n and k are the number of edges, vertices and components of G, respectively. In this paper, some upper bounds on the diameter of a chemical graph in terms of its inverse degree are given. We also obtain an ordering of connected chemical graphs with respect to the inverse degree.

Microwave Dielectric Properties of $Mg_4(Nb_{2-x}V_x)O_9$ Ceramics Produced by a Hydrothermal Method (수열합성법에 의해 제조한 $Mg_4(Nb_{2-x}V_x)O_9$ 세라믹스의 마이크로파 유전특성)

  • Lee, Sang-Wook;Lim, Sung-Woo;Kim, Yoon-Tae;Bang, Jae-Cheol
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
    • /
    • pp.300-301
    • /
    • 2007
  • $Mg_4(Nb_{2-x}V_x)O_9$ (MNV) ceramics have been prepared by a hydrothermal method. Low-temperature sintering of $Mg_4(Nb_{2-x}V_x)O_9$ (MNV) by V substitution for Nb was discussed in this study. A $Q{\cdot}f_0$ value of 103,297 GHz with a ${\varepsilon}_r$ of 12.56 and a ${\tau}_f$ of $-10.53\;ppm/^{\circ}C$ was obtained when x=0.0625 after sintering at $1100^{\circ}C$ for 5 h.

  • PDF

Thereshold Switching into Conductance Quantized Sttes in V/vamorphous- $V_{2}$ $O_{5}$/V Thin Film Devices (V/비정질- $V_{2}$ $O_{5}$ /lV 박막소자에서의 양자화된 컨덕턴스 상태로의 문턱 스위칭)

  • 윤의중
    • Journal of the Korean Institute of Telematics and Electronics D
    • /
    • 제34D권12호
    • /
    • pp.89-100
    • /
    • 1997
  • This paper investigated a new type of low voltage threshold switch (LVTS). As distinguished from the many other types of electronic threshold switches, the LvTS is ; voltage controlled, occurs at low voltages ($V_{2}$ $O_{5}$lV devices. The average low threshold voltage < $V_{LVT}$>=218 mV (standard deviation =24mV~kT/q, where T=300K), and was independent of the device area (x100) and amorphous oxide occurred in an ~22.angs. thick interphase of the V/amorphous- $V_{2}$ $O_{5}$ contacts. At $V_{LVT}$ there was a transition from an initially low conductance (OFF) state into a succession of quantized states of higher conductance (ON). The OFF state was spatically homogeneous and dominated by tunneling into the interphase. The ON state conductances were consistent with the quantized conductances of ballistic transport through a one dimensional, quantum point contact. The temeprature dependence of $V_{LVT}$, and fit of the material parameters (dielectric function, barrier energy, conductivity) to the data, showed that transport in the OFF and ON states occurred in an interphase with the characteristics of, respectively, semiconducting and metallic V $O_{2}$. The experimental results suggest that the LVTS is likely to be observed in interphases produced by a critical event associated with an inelastic transfer of energy.rgy.y.rgy.

  • PDF

Fabrication and Characteristics of ultra power-saving Schottky barrier rectifier (초절전형 Schottky barrier rectifier의 제조 및 그 특성)

  • Kim, Jun-Sik;Choe, Yeong-Ho;Park, Geun-Yeong;Choe, Si-Yeong
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • 제39권4호
    • /
    • pp.35-40
    • /
    • 2002
  • Ultra-power-saving SBR has been fabricated by using vanadium and molybdenum with low work function. Because reverse leakage current is increased in inverse proportion to work function, we implanted argon ion on the n-Si layer for decreasing leakage current. The dose and acceleration energy of the argon implantation in the silicon was 1$\times$10$^{14}$ ion/$\textrm{cm}^2$, 40 keV, respectively. The forward voltages drop of fabricated V-SBR and Mo-SBR were 0.25 V and 0.39 V at the same forward current density of 60 A/$\textrm{cm}^2$. As a result, it was found that the reverse leakage current of the fabricated V-SBR was reduced over 20$mutextrm{A}$ by the argon implantation in comparison with the no implanted V-SBR. Also, owing to argon implantation, the inferiority of characteristic of the SBR was not detected.

The application of a numerical technique to the current interruption properties of 800kV gas circuit breaker - Characteristics of gas flow (800kV 가스차단기의 차단성능평가를 위한 수치해석 적응 - 유동특성)

  • Choi, Y.K.;Song, K.D.;Park, K.Y.;Shin, Y.J.;Chulkov, V.V.
    • Proceedings of the KIEE Conference
    • /
    • 대한전기학회 1996년도 하계학술대회 논문집 C
    • /
    • pp.1888-1891
    • /
    • 1996
  • Recently, FLIC(Fluid In Cell) method has been widely used for the compressible. flow computation. A program which adopts the FLIC method and can analyze the flow conditions with arc in the interrupter was developed in our team. It was applied to the 800kV class gab circuit breaker for flow conditions with arc, and the results are presented and discussed in this paper.

  • PDF

Expression Analyses of MicroRNAs in Hamster Lung Tissues Infected by SARS-CoV-2

  • Kim, Woo Ryung;Park, Eun Gyung;Kang, Kyung-Won;Lee, Sang-Myeong;Kim, Bumseok;Kim, Heui-Soo
    • Molecules and Cells
    • /
    • 제43권11호
    • /
    • pp.953-963
    • /
    • 2020
  • Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an infectious disease with multiple severe symptoms, such as fever over 37.5℃, cough, dyspnea, and pneumonia. In our research, microRNAs (miRNAs) binding to the genome sequences of severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory-related coronavirus (MERS-CoV), and SARS-CoV-2 were identified by bioinformatic tools. Five miRNAs (hsa-miR-15a-5p, hsa-miR-15b-5p, hsa-miR-195-5p, hsa-miR-16-5p, and hsa-miR-196a-1-3p) were found to commonly bind to SARS-CoV, MERS-CoV, and SARS-CoV-2. We also identified miRNAs that bind to receptor proteins, such as ACE2, ADAM17, and TMPRSS2, which are important for understanding the infection mechanism of SARS-CoV-2. The expression patterns of those miRNAs were examined in hamster lung samples infected by SARS-CoV-2. Five miRNAs (hsa-miR-15b-5p, hsa-miR-195-5p, hsa-miR-221-3p, hsa-miR-140-3p, and hsa-miR-422a) showed differential expression patterns in lung tissues before and after infection. Especially, hsa-miR-15b-5p and hsa-miR-195-5p showed a large difference in expression, indicating that they may potentially be diagnostic biomarkers for SARS-CoV-2 infection.

Effects of Ventilation Types on Interior Environment of the Enclosed Farrowing-Nursery Pig House (무창 분만 ${\cdot}$ 자돈사 환기 형태가 돈사내 환경에 미치는 영향)

  • Yoo, Y.H.;Song, J.I.;Kang, H.S.;Jeon, B.S.;Kim, T.I.;Kim, H.H.
    • Journal of Animal Environmental Science
    • /
    • 제8권2호
    • /
    • pp.79-86
    • /
    • 2002
  • This study was conducted to collect basic data about the effects of ventilation types on the interior environment of the enclosed farrowing-nursery pig house in Anseong, Icheon and Jeungpyong. Surveyed ventilation types in the enclosed farrowing-nursery pig house are classified in to 4 types. In V1 type, air enters through a planar slot inlet placed on the juncture of the entering wall and exit through the chimney fan outlet; in V2 type, air enters through a perforated ceiling inlet and exits chimney fan outlet(V2); in V3 type, air enters through a circular duct inlet and exit chimney fan outlet(V3); in V4 type, enters through a circular duct inlet and exits side wall exhaust fan outlet(V4). Temperature, relative humidity, air velocity and ammonia concentration($NH_3$) were measured in the interior of swine building in the summer. Interior temperature was not remarkably different in all ventilation types in this study. However, temperature of the V4 was somewhat lower than that of the other types. Air velocity of the V4 was higher and $NH_3$ concentration of the V4 was lower than those of other ventilation types. It is suggested that the V4 ventilation type be applicable in the enclosed farrowing-nursery pig house in Korea.

  • PDF