• Title/Summary/Keyword: C-V characteristics

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A Study on the Ontology Modeling by Analyzing RiC-CM v0.2 (RiC-CM v0.2 분석을 통한 온톨로지 모델링에 관한 연구)

  • Jeon, Ye Ji;Lee, Hyewon
    • Journal of Korean Society of Archives and Records Management
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    • v.20 no.1
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    • pp.139-158
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    • 2020
  • This study is the first paper to introduce in the country the preview of RiC-CM v0.2, the standard for the description of records based on archival principles by the ICA in December 2019, and an early stage of research that considers how to apply it at archive management. This study was conducted as follows. First, this study compared and analyzed entities, attributes, and relations of RiC-CM v0.1 and v0.2, and extracted the characteristics of version 0.2. Second, this study tried to confirm the semantic structure of the archives by constructing the ontology modeling in consideration of the basic principle and the extracted characteristics of version 0.2, and built ontology modeling using Protégé. Finally, this study figured out the differences from version 0.1 through entering individuals into Protégé and examined how the characteristics of version 0.2 was represented by ontology.

A Study on Dynamic Characteristics of a Refrigeration System by Controlling the Evaporator Superheat (증발기 과열도제어에 따른 냉동장치의 동특성에 관한 연구)

  • 김재돌;오후규;윤정인
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.8
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    • pp.2012-2021
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    • 1995
  • An experimental study was performed for the analysis of dynamic characteristics of refrigeration system by controlling the evaporator superheat. Experimental data have been taken utilizing two different devices, thermostatic expansion valve(T.E.V.) and electronic expansion valve(E.E.V.), for the control of the evaporator superheat. The ranges of parameters, such as superheat, mass flow rate of refrigerant and inlet temperature of evaporator were 5-30.deg. C 90-170 kg/h and 10-25.deg. C, respectively. The data taken from the T.E.v.and E.E.v.were discussed with the control of the superheat, pressure drop, refrigerating capacity, compression work, evaporating temperature, condensing temperature and COP affecting performance characteristics of refrigeration system. In case of the refrigerant flow control with T.E..V., the superheat and pressure drop of the evaporator varied periodically, but the control with E.E.V., the parameters were very stable. In E.E.v.control, refrigerating capacity, compression work and evaporating temperature were decreased with increasing superheat, and the highest COP was obtained in the range of superheat from 5.deg. C to 15.deg. C.

I-V Characteristics of Epitaxial $CoSi_2$-contacted p+/n Junctions (Epitaxial $CoSi_2$접촉 p+/n 접합의 I-V 특성)

  • 구본철;김시중;김주연;배규식
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.11
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    • pp.908-913
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    • 2000
  • CoSi$_2$/p+/n diodes(bilayer diodes) were fabricated by using epitaxial CoSi$_2$grown from Co/Ti bilayer as a diffusion source. The I-V characteristics of p+/n diodes were measured and compared with those of diode made from Co monolayer (monolayer diode). Monolayer diodes showed typical p+n junction characteristics with the leakage current of as low as 10$^{-12}$ A and forward current 6-orders higher than the leakage current, when drive-in annealed at 90$0^{\circ}C$ for 20 sec.. On the other hand, bilayer diodes showed the Schottky-like behaviors with forward currents rather higher than those of monolyer diodes, but with too high leakage currents, when drive-in annealed at $700^{\circ}C$ or higher. However, when the annealing temperature was lowered to $700^{\circ}C$ and annealing time was increased to 60 sec., the leakage current was reduced to 10$^{-11}$ A and thus sho3wed typical diode characteristics. The high leakage currents for diodes annealed at $700^{\circ}C$ or higher was attributed to Shannon contacts formed due to unremoved Co-Ti-Si precipitates. But when annealed at 50$0^{\circ}C$, B ions diffused in the direction of the surface layer, and thus the leakage currents were reduced by removing Shannon contacts.

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Breakdown, V-t and Degradation Characteristics of Insulation in Liquid Nitrogen for HTS Transformer (고온초전도 변압기를 위한 액체질소 중 절연 파괴, V-t. 열화 특성)

  • Nguyen, Van-Dung;Joung, Jong-Man;Baek, Seung-Myeong;Lee, Chang-Hwa;Suck, Song-Hee;Kim, Sang-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.6
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    • pp.316-323
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    • 2004
  • HTS transformer is one of the most promising devices to supply enough electric energy for quick increase consumption. However, for practical design of the HTS transformer, it is necessary to establish the research on breakdown, V-t characteristics, degradation, and so on. In this paper, we discussed breakdown characteristics and V-t characteristics of polyimide/L$N_2$ and glass fiber reinforced plastic/$LN_2$ composite insulations. These composite insulations have been used as turn-to-turn and layer-to-layer insulations for HTS transformer respectively, Moreover, we investigated the degradation of these insulation samples after breakdown using microscope and SEM photograph.

The characteristics of D.C. switching threshold voltage for amorphous $As_{10}Ge_{15}Te_{75}$ thin film (비정질 $As_{10}Ge_{15}Te_{75}$박막의 D.C. 스위칭 임계전압 특성)

  • 이병석;이현용;이영종;정홍배
    • Electrical & Electronic Materials
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    • v.9 no.8
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    • pp.813-818
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    • 1996
  • Amorphous As$_{10}$Ge$_{15}$ Te$_{75}$ device shows the memory switching characteristics under d.c. bias. In bulk material, a-As$_{10}$Ge$_{15}$ Te$_{75}$ switching threshold voltage (V$_{th}$) is very high (above 100 volts), but in the case of thin film, V$_{th}$ decreases to a few or ten a few volts. The characteristics of V$_{th}$ depends on the physical dimensions such as the thickness of thin film and the separation between d.c. electrodes, and the annealing conditions. The switching threshold voltage decreases exponentially with increasing annealing temperature and annealing time, but increases linearly with the thickness of thin film and exponentially with increasing the separation between d.c. electrodes. The desirable low switching threshold voltage, therefore, can be obtained by the stabilization through annealing and changing physical dimensions.imensions.sions.

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Characteristics of Pd/polycrystalline 3C-SiC Schottky diodes for high temperature gas sensors (고온 가스센서용 Pd-다결정 3C-SiC 쇼트키 다이오드의 특성)

  • Ahn, Jeong-Hak;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.275-275
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    • 2008
  • This paper describe the fabrication of a Pd/polycrystalline 3C-SiC schottky diode and its characteristics, in which the polycrystalline 3C-SiC layer and Pd Schottky contact were deposited by using APCVD and sputter, respectively. Crystalline quality, uniformity, and preferred orientations of the Pd thin film were evaluated by SEM and XRD, respectively. Pd/poly 3C-SiC Schottky diodes were fabricated and characterized by I-V and C-V measurements. Its electric current density Js and barrier height voltage were measured as $2\times10^{-3}$ A/$cm^2$ and 0.58 eV, respectively. These devices were operated until about $400^{\circ}C$. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature chemical sensor applications.

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Effect of Cooling Rate on DC Accelerated Aging Characteristics of ZPCCY-Based Varistor Ceramics (ZPCCY계 바리스터 세라믹스의 DC 가속열화 특성에 미치는 냉각속도의 영향)

  • 남춘우;김향숙
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.9
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    • pp.776-782
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    • 2002
  • The microstructure, V-Ι characteristics, and stability of ZnO-P $r_{6}$ $O_{11}$ CoO-C $r_2$ $O_3$- $Y_2$ $O_3$-based varistor ceramics were investigated with cooling rate in the range of 2~8$^{\circ}C$/min. The cooling rate relatively weakly affected the microstructure, the varistor voltage, and the leakage current in the V-Ι characteristics. But the nonlinear exponent relatively strongly affected by cooling rate. The cooling rate also greatly affected the stability of V-Ιand dielectric characteristics for DC accelerated aging stress. On the whole, the varistors cooled with 4$^{\circ}C$/fin exhibited the highest performance in the densification, nonlinearity, and stability. Especially, they exhibited a high stability, in which the variation rate of the varistor voltage( $V_{1㎃}$), the nonlinear exponent($\alpha$), and the dissipation factor(tan $\delta$) is -1.4%, -4.9%, and +60.0%, respectively, under DC accelerated aging stress such as 0.95 $V_{1㎃}$15$0^{\circ}C$/12 h)

A simulation study on the figure of merit optimization of a 1200V 4H-SiC DMOSFET (1200V급 4H-SiC DMOSFET 성능지수 최적화 설계 시뮬레이션)

  • Choi, Chang-Yong;Kang, Min-Suk;Bang, Wook;Kim, Sang-Chul;Kim, Nam-Kyun;Koo, Sang-Mo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.63-63
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    • 2009
  • In this work, we demonstrate 800V 4H-SiC power DMOSFETs with several structural alterations to observe static DC characteristics, such as a threshold voltage ($V_{TH}$) and a figure of merit ($V_B^2/R_{SP,ON}$). To optimize the static DC characteristics, we consider four design parameters; (a) the doping concentration ($N_{CSL}$) of current spreading layer (CSL) beneath the p-base region, (b) the thickness of p-base ($t_{BASE}$), (c) the doping concentration ($N_J$) and width ($W_J$) of a JFET region, (d) the doping concentration ($N_{EPI}$) and thickness ($t_{EPI}$) of epi-layer. Design parameters are optimized using 2D numerical simulations and the 4H-SiC DMOSFET structure results in high figure of merit ($V_B^2/R_{SP,ON}$>~$340MW/cm^2$) for a power MOSFET in $V_B{\sim}1200V$ range.

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Study on Electric Charactreistics of Multi-dielectric Thin Films Using Amorphous Silicon (비정질 실리콘을 이용한 다층 유전 박막의 전기적 특성에 관한 연구)

  • 정희환;정관수
    • Journal of the Korean Vacuum Society
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    • v.3 no.1
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    • pp.71-76
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    • 1994
  • The electrical characteristics of the capacitor dielectric films of amorphous silicon-nit-ride-oxide(ANO) structures are compared with the capacitor dielectric films of oxide-nitride-oxide (ONO) structrues The electrical characteristics of ONO and ANO films were evaluated by high frequency(1 MHz) C-V high frequency C-V after constant voltage stree I-V TDDB and refresh time measurements. ANO films shows good electrical characteristics such as higher total charge to breakdown storage capacitance and longer refresh time than ONO films. Also it makes little difference that leakage current and flat band voltage shyift(ΔVfb)of ANO ana ONO films.

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Fabrication and characteristics of polycrystalline 3C-SiCSchottky diodes for high temperature chemical sensors (고온 화학센서용 다결정 3C-SiC 쇼트키 다이오드 제작과 그 특성)

  • Chung, Gwiy-Sang;Ahn, Jeong-Hak
    • Journal of Sensor Science and Technology
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    • v.17 no.6
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    • pp.414-417
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    • 2008
  • This paper describes the fabrication of a Pd/poly 3C-SiC Schottky diode and its characteristics, in which the poly 3C-SiC layer and Pd Schottky contact were deposited by using APCVD and sputter, respectively. Crystalline quality, uniformity, and preferred orientations of the Pd thin film were evaluated by SEM and XRD, respectively. Pd/poly 3C-SiC schottky diodes were fabricated and characterized by I-V and C-V measurements. Its electric current density Js and barrier height voltage were measured as $2{\times}10^{-3}A/cm^2$ and 0.58 eV, respectively. These devices were operated until about $400^{\circ}C$. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature chemical sensor applications.