• 제목/요약/키워드: High Resistivity

검색결과 1,273건 처리시간 0.027초

전기비저항, 바크하우젠노이즈 및 탄화물 분석법을 이용한 2.25Cr-1Mo 강의 열화도 평가 (Evaluation of degradation in aged 2.25CrMo steel by electrical resistivity, magnetic Barkhausen noise and carbide analysis)

  • 변재원;표승우;권숙인
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집A
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    • pp.210-215
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    • 2001
  • The ferritic 2.25CrMo steel has been used for high temperature structure applications such as turbine rotors, boilers and pressure vessels in fossil plant and petroleum chemical facilities. However, this steel is known to result in aging degradation due to temper embrittlement, carbide induced brittleness and softening of matrix after long time exposure to high temperature. This research investigated the microstructural and mechanical changes after artificial degradation treatment and evaluated the degree of degradation by several nondestructive methods. The decrease of electrical resistivity and increase of magnetic Barkhausen noise(RMS voltage) with increasing aging time were observed. The change of electrical resistivity and Barkhausen noise showed a good correlation with the ductile-brittle transition temperature.

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BTA를 첨가한 초고압변압기유의 유동시 체적고유저항특성 (The Volume Resistivity Characteristics on Fluid Flow of Ultra-High Voltage Transformer Oils added BTA)

  • 이용우;이수원;신현택;한상섭;홍진웅
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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    • pp.267-269
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    • 1997
  • The electrical properties due to the Benzotriazole(following as BTA) additive in fluids for insulating and cooling the ultra-high voltage transformer is studied in this paper. Specimen having the several contents of BTA, such as 5[ppm]. 10[ppm] and 30[ppm] is used in order to investigate the characteristics on volume resistivity in case of fluid flow in experimental device made in lab. Volume resistivity is decreased with an increase of fluid flow velocity and increased with BTA content in low temperature region, but volume resistivity of specimen contained BTA 10[ppm] is the largest thing over $30[^{\circ}C]{\sim}50[^{\circ}C]$ than the others in experiment.

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Electrical Resistivity and Charge Density of Bismuth Telluride Doped with Erbium

  • Yeom, Tae-Ho
    • Journal of Magnetics
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    • 제10권4호
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    • pp.149-151
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    • 2005
  • The electric properties of a single crystal bismuth telluride doped with a small concentration of Erbium, $Bi_{z-x}Er_xTe_3$ with x = 0.002, are investigated as a function of temperature. The resistivity was obtained by using the van der Pauw method. The measured electrical resistivity is 78 ${\mu}{\Omega}cm$ at 4.2 K. The charge density of $Bi_{z-x}Er_xTe_3$ is found to be $2{\times}10^{19}/cm^3$ at 4.2 K. It turns out that $Bi_{z-x}Er_xTe_3$ is a p-type semiconductor. It is discussed that the high mobility and less density support that $Bi_{z-x}Er_xTe_3$ is a potential sensor with high energy resolution. Comparison with an established material (i.e. Au:Er alloy) is also discussed.

SiO2 첨가가 AIN 세라믹스의 고온 비저항에 미치는 영향 (Effects of SiO2 on the High Temperature Resistivities of AIN Ceramics)

  • 이원진;김형태;이성민
    • 한국세라믹학회지
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    • 제45권1호
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    • pp.69-74
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    • 2008
  • The effects of $SiO_2$ impurity on the high temperature resistivities of AIN ceramics have been investigated. When $SiO_2$ was added into 1 wt% $Y_2O_3$-doped AIN, DC resistivities have decreased and electrode polarizations disappeared. Impedance spectroscopy showed two semi-circles at $600^{\circ}C$, which were attributed to grain and grain boundary, respectively. $SiO_2$ doping had more significant effects on the grain resistivity than grain boundary resistivity, implying that doped Si acted as a donor in AIN lattice. In addition, voltage dependency of DC resistivity was observed, which might be related to dependency of size of grain boundary semi-circle on the bias voltage in impedance spectroscopy.

High Resistivity SOI MOS 버랙터를 위한 RF 대신호 모델 연구 (A Study on RF Large-Signal Model for High Resistivity SOI MOS Varactor)

  • 홍서영;이성현
    • 전자공학회논문지
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    • 제53권9호
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    • pp.49-53
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    • 2016
  • RF 채널 분포효과를 위한 전압 종속 외부 게이트 커패시턴스가 사용된 High resistivity(HR) silicon-on-insulator(SOI) RF accumulation-mode MOS 버랙터의 대신호 모델이 새롭게 개발되었다. 이 모델의 전압 종속 파라미터들은 정확한 S-파라미터 optimization을 사용하여 추출되었고, 이를 피팅하여 empirical 모델 방정식을 구축하였다. 이러한 새로운 대신호 RF 모델은 넓은 전압영역에서 측정된 Y11-파라미터 데이터와 20 GHz까지 잘 일치함으로써 정확도가 검증되었다.

High Resistivity SOI RF CMOS 대칭형 인덕터 모델링을 위한 개선된 Optimization 방법 연구 (A Study on Improved Optimization Method for Modeling High Resistivity SOI RF CMOS Symmetric Inductor)

  • 안자현;이성현
    • 전자공학회논문지
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    • 제52권9호
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    • pp.21-27
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    • 2015
  • High resistivity(HR) silicon-on-insulator(SOI) RF CMOS 공정 인덕터의 모델 파라미터를 정확히 결정하기 위하여 직접추출과 simultaneous optimization을 사용한 개선된 방법을 개발하였다. 먼저, 대칭형 인덕터와 센터탭이 접지된 대칭형 인덕터 등가회로들의 Y 및 Z-파라미터 방정식 유도를 통해 일부 모델 파라미터들을 직접 추출하고, 병렬 저항과 전체 인덕턴스 방정식들로 미지 변수들을 줄여 모델링 정확도를 향상시켰다. 또한, 두 등가회로의 동일한 모델 파라미터들을 공통 변수로 두고 S-파라미터 데이터 세트를 동시에 optimization함으로써 optimization 정확도를 크게 향상시켰다.

실리콘 웨이퍼 비저항에 따른 Dopant-Free Silicon Heterojunction 태양전지 특성 연구 (The Influence of the Wafer Resistivity for Dopant-Free Silicon Heterojunction Solar Cell)

  • 김성해;이정호
    • 한국표면공학회지
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    • 제51권3호
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    • pp.185-190
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    • 2018
  • Dopant-free silicon heterojunction solar cells using Transition Metal Oxide(TMO) such as Molybdenum Oxide($MoO_X$) and Vanadium Oxide($V_2O_X$) have been focused on to increase the work function of TMO in order to maximize the work function difference between TMO and n-Si for a high-efficiency solar cell. One another way to increase the work function difference is to control the silicon wafer resistivity. In this paper, dopant-free silicon heterojunction solar cells were fabricated using the wafer with the various resistivity and analyzed to understand the effect of n-Si work function. As a result, it is shown that the high passivation and junction quality when $V_2O_X$ deposited on the wafer with low work function compared to the high work function wafer, inducing the increase of higher collection probability, especially at long wavelength region. the solar cell efficiency of 15.28% was measured in low work function wafer, which is 34% higher value than the high work function solar cells.

전기 집진기의 집진 효율 향상에 관한 연구 (The Improvement of Collection Efficiency of Electrostatic Precipitator)

  • 안국찬;김봉환;이광석
    • 한국안전학회지
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    • 제17권4호
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    • pp.25-30
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    • 2002
  • This paper demonstrates the effects of dust electrical resistivity on electrostatic precipitability. The effects of gas temperature, velocity and humidity on the collection efficency were considered by used of coal fly ashes from fluidized bed combustion boiler. The experiments for collection efficiency were carried out in the pilot plant. The ashes which have non-spherical geometry and high electrical resistivity were used. Electrical resistivity is an important property for the collection efficiency in the electrostatic precipitators. Fly ash resistivity as a function of temperature up $350{\circ}C$ and water concentration(up to 15%) has been experimentally investigated using the resistivity test equipment consisted of the movable electrode, dust cup, and furnace. As the resistivity of fly ash in the operating temperature($150{\circ}C$) of an electrostatic precipitator was measured higher than $1010{\Omega}{\cdot}$cm, flue gas conditioning in the electrostatic precipitator to reduce the resistivity of fly ash is required.

Study of Magnetic Field Shielded Sputtering Process as a Room Temperature High Quality ITO Thin Film Deposition Process

  • Lee, Jun-Young;Jang, Yun-Sung;Lee, You-Jong;Hong, Mun-Pyo
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.288-289
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    • 2011
  • Indium Tin Oxide (ITO) is a typical highly Transparent Conductive Oxide (TCO) currently used as a transparent electrode material. Most widely used deposition method is the sputtering process for ITO film deposition because it has a high deposition rate, allows accurate control of the film thickness and easy deposition process and high electrical/optical properties. However, to apply high quality ITO thin film in a flexible microelectronic device using a plastic substrate, conventional DC magnetron sputtering (DMS) processed ITO thin film is not suitable because it needs a high temperature thermal annealing process to obtain high optical transmittance and low resistivity, while the generally plastic substrates has low glass transition temperatures. In the room temperature sputtering process, the electrical property degradation of ITO thin film is caused by negative oxygen ions effect. This high energy negative oxygen ions(about over 100eV) can be critical physical bombardment damages against the formation of the ITO thin film, and this damage does not recover in the room temperature process that does not offer thermal annealing. Hence new ITO deposition process that can provide the high electrical/optical properties of the ITO film at room temperature is needed. To solve these limitations we develop the Magnetic Field Shielded Sputtering (MFSS) system. The MFSS is based on DMS and it has the plasma limiter, which compose the permanent magnet array (Fig.1). During the ITO thin film deposition in the MFSS process, the electrons in the plasma are trapped by the magnetic field at the plasma limiters. The plasma limiter, which has a negative potential in the MFSS process, prevents to the damage by negative oxygen ions bombardment, and increases the heat(-) up effect by the Ar ions in the bulk plasma. Fig. 2. shows the electrical properties of the MFSS ITO thin film and DMS ITO thin film at room temperature. With the increase of the sputtering pressure, the resistivity of DMS ITO increases. On the other hand, the resistivity of the MFSS ITO slightly increases and becomes lower than that of the DMS ITO at all sputtering pressures. The lowest resistivity of the DMS ITO is $1.0{\times}10-3{\Omega}{\cdot}cm$ and that of the MFSS ITO is $4.5{\times}10-4{\Omega}{\cdot}cm$. This resistivity difference is caused by the carrier mobility. The carrier mobility of the MFSS ITO is 40 $cm^2/V{\cdot}s$, which is significantly higher than that of the DMS ITO (10 $cm^2/V{\cdot}s$). The low resistivity and high carrier mobility of the MFSS ITO are due to the magnetic field shielded effect. In addition, although not shown in this paper, the roughness of the MFSS ITO thin film is lower than that of the DMS ITO thin film, and TEM, XRD and XPS analysis of the MFSS ITO show the nano-crystalline structure. As a result, the MFSS process can effectively prevent to the high energy negative oxygen ions bombardment and supply activation energies by accelerating Ar ions in the plasma; therefore, high quality ITO can be deposited at room temperature.

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Surface Oxidation Effect During high Temperature Vacuum Annealing on the Electrical Conductivity of ZnO thin Films Deposited by ALD

  • Kim, Jin-Yong;Choi, Yong-June;Park, Hyung-Ho
    • 마이크로전자및패키징학회지
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    • 제19권2호
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    • pp.73-78
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    • 2012
  • The chemical, electrical, and optical properties of ZnO and Al-doped ZnO films after high temperature annealing were studied. The resistivity increased significantly after annealing at $600^{\circ}C$ under $10^{-10}$ Torr atmosphere. The mechanism of the resistivity change was explored using photoemission spectroscopy and photoluminescence spectrometer. The results indicated that the amount of oxygen deficient region O-Zn bonds decreased and oxygen vacancy was decreased after the high temperature vacuum annealing. The increase in the resistivity of ZnO and Al-doped ZnO films was resulted from the decrease in carrier concentration due to a decrease in the amount of oxygen deficiency.