• 제목/요약/키워드: EPI

검색결과 543건 처리시간 0.025초

IGBT 순방향 전압강하의 계산 (Calculation of Forward Voltage Drop of IGBTs)

  • 최병성;정상구
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제49권3호
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    • pp.161-164
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    • 2000
  • A simple methode for calculating the forward voltage drop of IGBTs is presented, on the voltage drops on the p+ body, the reverse biased depletion region between p+body and epi-layer, the epi layer, and the forward biased collector junction. The decrease of the total current density in the epi layer near the p+ body is taken into account. The proposed methode allows a simple but accurate determination of the forward voltage drop in IGBTs, avoiding the complex path taken in the previous model for the forward voltage drops on channel, accumulation region, and epi region. Numerical simulations for 1kV NPT-IGBT with a uniformly doped collector are shown to support the analytical results.

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Cloning of Epidermis-specific cDNAS Encoding a Lipid Transfer Protein and an Aldehyde Decarbonylase from Senecio odorus

  • Pyee, Jaeho
    • Journal of Plant Biology
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    • 제39권3호
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    • pp.189-195
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    • 1996
  • The major cuticular components have been shown to be synthesized in the epidermis. Therefore, cloning of epidermis-specific genes could yield information to be used to isolate and characterize the enzymes involved in the cuticle biosynthesis. A subtractive cDNA library was prepared from Senecio odorus in which epidermis-specific cDNAs were enriched. Differential screening of the library using epidermal and non-epidermal probes revealed two cDNAs. One of them designated epi425 was identified, based on the sequence homology, as a member of a new class in the LTP gene family and the other clone designated epi23 as a gene encoding an aldehyde decarbonylase. Northern blot analyses showed that epi425 and epi23 cDNAs hybridized with a transcript of about 600 and 2, 100 nucleotides, respectively, from the epidermis but not from the non-epidermal tissues. Further characterization of these clones will provide more information on the mechanism of the cuticle biosynthesis.

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RESURE LDMOS의 항복전압에 관한 이론적인 고찰 (A theoretical study on the breakdown voltage of the RESURF LDMOS)

  • 한승엽;정상구
    • 전자공학회논문지D
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    • 제35D권8호
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    • pp.38-43
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    • 1998
  • An analytical model for the surface field distribution of the RESURF (reduced surface field)LD(lateral double-diffused) MOS is presented in terms of the doping concentration, the thickness of the n epi layer, the p substrate concentration, and the epi layer length. The reuslts are used to determine the breakdown voltage due to the surface field as a function of the epi layer length. The maximum breakdown voltage of the device is found to be that of the vertical n$^{+}$n$^{[-10]}$ p$^{[-10]}$ junction. Analytical results of the breakdown voltage vs. the epi layer length agree well with the numerical simulation results using MEDICI.I.

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활성화한 RAW 264.7 세포주에서 8-epi-xanthatin의 Nitric Oxide 생성저해 (Inhibition of Nitric Oxide Synthesis by 8-epi-xanthatin in Activated RAW 264.7 Cells)

  • 이화진;정연수;류시용;류재하
    • 약학회지
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    • 제42권5호
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    • pp.540-543
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    • 1998
  • The nitric oxide (NO) produced in large amounts by inducible nitric oxide synthase is known to be responsible for the vasodilation and hypotension observed in septic shock. We have found that 8-epi-xanthatin from Xanthium strumarium L. inhibited the production of NO in LPS-activated RAW 264.7 cells ($IC_{50}$ value was 1.5 ${\mu}$M). This activity was resulted from the suppressing of inducible nitric oxide synthase enzyme expression.

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4H-SiC RESURF LDMOSFET 소자의 전기적 특성분석 (Analysis of the Electrical Characteristics of 4H-SiC LDMOSFET)

  • 김형우;김상철;방욱;김남균;서길수;김은동
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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    • pp.101-102
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    • 2005
  • SiC lateral power semiconductor device has high breakdown voltage and low on-state voltage drop due to the material characteristics. And, because the high breakdown voltage can be obtained, RESURF technique is mostly used in silicon power semiconductor devices. In this paper, we presents the electrical characteristics of the 4H-SiC RESURF LDMOSFET as a function of the epi-layer length, concentration and thickness. 240~780V of breakdown voltage can be obtained as a function of epi-layer length and thickness with same epi-layer concentration.

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PKC inhibitors RO 31-8220 and Gö 6983 enhance epinephrine-induced platelet aggregation in catecholamine hypo-responsive platelets by enhancing Akt phosphorylation

  • Kim, Sun-Young;Kim, Se-Woon;Kim, Jeong-Mi;Jho, Eek-Hoon;Park, Seon-Yang;Oh, Do-Yeun;Yun-Choi, Hye-Sook
    • BMB Reports
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    • 제44권2호
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    • pp.140-145
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    • 2011
  • Impaired responsiveness of platelets to epinephrine (epi) and other catecholamines (CA) has been reported in approximately 20% of the healthy Korean and Japanese populations. In the present study, platelet aggregation induced by epi was potentiated by RO 31-8220 (RO) or G$\ddot{o}$ 6983 (G$\ddot{o}$). Phosphorylated Akt (p-Akt) was very low in epi-stimulated PRP from CA-hypo- responders (CA-HY), whereas it was detected in those from CA-good responders (CA-GR). RO and G$\ddot{o}$ increased p-Akt, one of the major downstream effectors of phosphoinositol-3 kinase (PI3K), in epi-stimulated PRP from both groups. Wortmannin, a PI3K inhibitor, attenuated the RO or G$\ddot{o}$-induced potentiation of p-Akt in epi-stimulated PRP, suggesting positive effects for RO and G$\ddot{o}$ on PI3K. $TXA_2$ formation was increased by the addition of either RO or G$\ddot{o}$ in epi-stimulated platelets. The present data also suggest that impaired Akt phosphorylation may be responsible for epinephrine hypo-responsiveness of platelets.

'Cyclitol 유도체(誘導體) 합성(合成)에 관(關)한 연구(硏究)' -Inositol stereomer 와 p-Hydroxybenzoate의 합성(合成)과 식품공업상(食品工業上) 응용(應用)을 위한 항균시험(抗菌試驗)- ('Studies on the Synthesis of Cyclitol derivatives' -Synthesis of Inositols, p-Hydroxybenzoates and thier Antimicrobial test for food industry)

  • 손주환
    • Applied Biological Chemistry
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    • 제13권3호
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    • pp.197-205
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    • 1970
  • 1. myo-inositol (aeeeee) 에서 scyllo- (eeeeee), epi-(aeaeee) 및 muco-inositol (aaaeee)에 도달(到達)시킬 수 있었다. 2. inositol의 과산화수소(過酸化水素) 산화(酸化)는 ax. 수산기(水酸基)가 산화(酸化)되어 microbial oxidation, 접촉산화(接觸酸化)에서와 대등(對等)한 inosose를 얻고, 이것은 산성(酸性)에서 $NaBH_4$로 환원(還元)하면 eq.-alcohol이 되며, 한편 접촉산원(接觸還元)하면 az. alcohol 이 된다. 3. inositol의 p-HBA ester인 사종(四種) 신화합물(新化合物) [III], [XII], [XVI], [XXI]을 합성(合成)하였다. 4. 이들 ester는 모두 항균작용(抗菌作用)이 있고 pH의 저하(低下)로 증대(增大)되는 경향(領向)이 있으며 muco-inositol ester는 가장 강력(强力)하고, 이는 입체구조(立體構造)와 관련(關聯)되는 것 같다.

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