• Title/Summary/Keyword: Thermal threshold

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The Optimal Design of Super High Voltage Planar Gate NPT IGBT (대용량 전력변환용 초고전압 NPT IGBT 최적화 설계에 관한 연구)

  • Kang, Ey Goo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.8
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    • pp.490-495
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    • 2015
  • This paper was proposed the theoretical research and optimal design 3,000 V IGBT for using electrical automotive, high speed train and first power conversion. To obtaining 3,000 V breakdown voltage, the design parameters was showed $160{\Omega}{\cdot}cm$ resistivity and $430{\mu}m$ drift length. And to maintain 5 V threshold voltage, we obtained $6.5{\times}10^{13}cm^{-2}$ p-base dose. We confirmed $24{\mu}m$ cell pitch for maintain optimal on state voltage drop and thermal characteristics. This 3,000 V IGBT was replaced to thyristor devices using first power conversion and high speed train, presently.

A study of the effect of the temperature on the As Te Ge Si amorphous semiconductor (As Te Ge Si 무정형 반도체의 온도영향)

  • 박창엽
    • 전기의세계
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    • v.23 no.6
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    • pp.49-55
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    • 1974
  • Amorphous semiconductor from As 30 Te 48 Ge 10 Si 12 was prepared, and studied electron microscopy, X-ray analysis and resistivity measurement. It's resistivity is 1.56*10$^{6}$ .ohm.-cm when small ampule is used for preparing sample it is found that no phase separation has occurced by electron microscopy, and that phase transition temperature is 232.deg. C by differential Thermal Analysis. The specimen showed threshold switching that the low resistance state occur at critical electric field and the resistance recover at low applied field. Critical electric field of the switching is 10$^{5}$ V/cm at room temperature. Threshold voltage secreace exponentially with increasing ambient temperature and at that each voltage resistance of the switching device increase exponentially. According to the series resistance and applied vottage current slope on the V-I curve is varied. When applied voltage is decreased after switching, the resistance of the switching device is increased. By this result the origin of the switching is the Joule's heating.

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The Characteristics of MOSFET with Reoxidized Nitrided Oxide Gate Dielectrics (재산화된 질화 산화막을 게이트 절연막으로 사용한 MOSFET의 특성)

  • 양광선;박훈수;김봉렬
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.28A no.9
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    • pp.736-742
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    • 1991
  • N$^{+}$poly gate NMOSFETs and p$^{+}$ poly gate (surface type) PMOSFETs with three different gate oxides(SiO2, NO, and ONO) were fabricated. The rapid thermal nitridation and reoxidation techniques have been applied to gate oxide formation. The current drivability of the ONO NMOSFET shows larger values than that of the SiO2 NMOSFET. The snap-back occurs at a lower drain voltage for SiO$_2$ cases for ONO NMOSFET. Under the maximum substrate current bias conditions, hot-carrier effects inducting threshold voltage shift and transconductance degradation were investigated. The results indicate that ONO films exhibit less degradation in terms of threshold voltage shift. It was confirmed that the ONO samples achieve good improvement of hot-carrier immunity. In a SiO$_2$ SC-PMOSFET, with significant boron penetration, it becomes a depletion type (normally-on). But ONO films show excellent impurity barrier properties to boron penetration from the gate.

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Effect of Post Annealing in Oxygen Ambient on the Characteristics of Indium Gallium Zinc Oxide Thin Film Transistors

  • Jeong, Seok Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.10
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    • pp.648-652
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    • 2014
  • We have investigated the effect of electrical properties of amorphous InGaZnO thin film transistors (a-IGZO TFTs) by post thermal annealing in $O_2$ ambient. The post-annealed in $O_2$ ambient a-IGZOTFT is found to be more stable to be used for oxide-based TFT devices, and has better performance, such as the on/off current ratios, sub-threshold voltage gate swing, and, as well as reasonable threshold voltage, than others do. The interface trap density is controlled to achieve the optimum value of TFT transfer and output characteristics. The device performance is significantly affected by adjusting the annealing condition. This effect is closely related with the modulation annealing method by reducing the localized trapping carriers and defect centers at the interface or in the channel layer.

The Involvement of Protein kinase C in Glutamate-Mediated Nociceptive Response at the Spinal Cord of Rats (흰쥐의 척수에서 Glutamate가 매개하는 Nociceptive Response에 있어서 Protein kinase C의 관련성)

  • 김성정;박전희;이영욱;양성준;이종은;이병천;손의동;허인회
    • YAKHAK HOEJI
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    • v.43 no.2
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    • pp.263-273
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    • 1999
  • When glutamate was infected intrathecally, the result is similar to those produced by TPA injected. The involvement of protein kinase C (PKC) in the nociceptive responses in rat dorsal horn neurons of lumbar spinal cord was studied. In test with formalin, a PKC inhibitor (chelerythrine) inhibited dose-dependently the formalin-induced behavior response. Neomycin also inhibited it significantly. But, a PKC activator (12-O-tetradecanoylphorbol-13-ester, TPA) showed reverse effect. When gluatamate was injected intrathecally, we observed the result is smilar to those produced by TPA injection. On the other hand, intrathecal injection of glutamate induced thermal and mechanical hyperalgesia. In Tail-flick test, we examined the involvement of PKC on the glutamate-indeced thermal hyperalgesia. Chelerythrine showed an inhibitory effect and TPA enhanced thermal response. Glutamate decreased the mechanical threshold significantly. A pretreatment of chelerythrine and neomycin inhibited glutamate-induced mechanical hyperalgesia, but the effect of neomycin was not significant. TPA had little effect on the mechanical nociceptive response. These results suggest that the PKC activation through metabotropic receptor at postsynaptic region of spinal cord dorsal horn neurons may influence on the persistent nociception produced by chemical stimulation with formalin, thermal and mechanical hyperalgesia induced by glutamate.

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Evolution of dynamic mechanical properties of heated granite subjected to rapid cooling

  • Yin, Tubing;Zhang, Shuaishuai;Li, Xibing;Bai, Lv
    • Geomechanics and Engineering
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    • v.16 no.5
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    • pp.483-493
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    • 2018
  • Experimental study of the deterioration of high-temperature rock subjected to rapid cooling is essential for thermal engineering applications. To evaluate the influence of thermal shock on heated granite with different temperatures, laboratory tests were conducted to record the changes in the physical properties of granite specimens and the dynamic mechanical characteristics of granite after rapid cooling were experimentally investigated by using a split Hopkinson pressure bar (SHPB). The results indicate that there are threshold temperatures ($500-600^{\circ}C$) for variations in density, porosity, and P-wave velocity of granite with increasing treatment temperature. The stress-strain curves of $500-1000^{\circ}C$ show the brittle-plastic transition of tested granite specimens. It was also found that in the temperature range of $200-400^{\circ}C$, the through-cracks induced by rapid cooling have a decisive influence on the failure pattern of rock specimens under dynamic load. Moreover, the increase of crack density due to higher treatment temperature will result in the dilution of thermal shock effect for the rocks at temperatures above $500^{\circ}C$. Eventually, a fitting formula was established to relate the dynamic peak strength of pretreated granite to the crack density, which is the exponential function.

A Study on Structural-Thermal-Optical Performance through Laser Heat Source Profile Modeling Using Beer-Lambert's Law and Thermal Deformation Analysis of the Mirror for Laser Weapon System (Beer-Lambert 법칙을 적용한 레이저 열원 프로파일 모델링 및 레이저무기용 반사경의 열변형 해석을 통한 구조-열-광학 성능 연구)

  • Hong Dae Gi
    • Journal of Aerospace System Engineering
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    • v.17 no.4
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    • pp.18-27
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    • 2023
  • In this paper, the structural-thermal-optical performance analysis of the mirror was performed by setting the laser heat source as the boundary condition of the thermal analysis. For the laser heat source model, the Beer-Lambert model considering semi-transparent optical material based on Gaussian beam was selected as the boundary condition, and the mechanical part was not considered, to analyze the performance of only the mirror. As a result of the thermal analysis, thermal stress and thermal deformation data due to temperature change on the surface of the mirror were obtained. The displacement data of the surface due to thermal deformation was fitted to a Zernike polynomial to calculate the optical performance, through which the performance of the mirror when a high-energy laser was incident on the mirror could be predicted.

An Organic Electrophosphorescent Device Driven by All-Organic Thin-Film Transistor using Polymeric Gate Insulator

  • Pyo, S.W.;Shim, J.H.;Kim, Y.K.
    • Journal of Information Display
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    • v.4 no.2
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    • pp.1-6
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    • 2003
  • In this paper, we demonstrate that the organic electrophosphorescent device is driven by the organic thin film transistor with spin-coated photoacryl gate insulator. It was found that electrical output characteristics in our organic thin film transistors using the staggered-inverted top-contact structure showed the non-saturated slope in the saturation region and the sub-threshold nonlinearity in the triode region, where we obtained the maximum power luminance that was about 90 $cd/m^2$. Field effect mobility, threshold voltage, and on-off current ratio in 0.45 ${\mu}m$ thick gate dielectric layer were 0.17 $cm^2/Vs$, -7 V, and $10^6$ , respectively. In order to form polyimide as a gate insulator, vapor deposition polymerization process was also introduced instead of spin-coating process, where polyimide film was co-deposited by high-vacuum thermal evaporation from 4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-oxydianiline (ODA) and cured at 150${\sqsubset}$for 1hr. It was also found that field effect mobility, threshold voltage, on-off current ratio, and sub-threshold slope with 0.45 ${\mu}m$ thick gate dielectric films were 0.134 $cm^2/Vs$, -7 V, and $10^6$ A/A, and 1 V/decade, respectively.

Electrical Switching Mechanism of the Sintering Oxides (산화물 소결체에서 전기적 Switching 기구)

  • 조동산;김화택
    • Journal of the Korean Ceramic Society
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    • v.15 no.3
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    • pp.135-139
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    • 1978
  • Sintering oxide which was prepared by sintering at $1200^{\circ}C$ the mixture of ${\gamma}$-$Fe_2O_3$ and $Sb_2O_3$ in 2 : 1 mol ratio, showed 1st electrical switching and stable 2nd switching when D.C. voltage was applied. This electrical switching mechanism was known to be thermal mechanism from dependence of environmental temperature of threshold Voltage(Vm), Current(Im) and the conductivity of the current filament of the sintering oxide.

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A Study on the efficiency test of Electric Discharge Machine Wire using Image processing (화상처리를 이용한 방전와이어의 성능평가에 대한 연구)

  • 배진한;이위로;유송민
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.10a
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    • pp.117-122
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    • 2002
  • Electrical discharge machining uses thermal energy from electrical discharge, while wire electrical discharge machining (WEDM) technology is widely used in conductive material machining. This paper proposes a method for evaluating the characteristics of wires in WEDM. In order to evaluate the wire processing performance, processing speed and roughness, straightness, corner processing have been assessed with precision experiment equipment and image processing including Laplacian filtering with various threshold levels.

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