• Title/Summary/Keyword: 전기저항률

Search Result 263, Processing Time 0.03 seconds

The Parallel Driving Characteristics of Piezoelectric Transformer (압전 변압기의 병렬 구동 특성)

  • Lee, J.S.;Hong, J.K.;Chai, H.I.;Yoon, M.S.;Jeong, S.H.;Lim, K.J.
    • Proceedings of the KIEE Conference
    • /
    • 2000.07c
    • /
    • pp.1584-1586
    • /
    • 2000
  • 본 논문에서는 압전 변압기의 병렬 구동에 대해 연구하였다. 병렬 구동을 함으로서 단일 구동시에 대해 $\sqrt{2}$정도의 출력 전압을 얻었다. 적외선 온도계를 이용하여 압전 변압기의 온도 상승률을 측정한 결과 단일 구동시보다 병렬 구동에 진동 손실 에너지의 감소를 얻을 수 있어 온도 상승률을 억제할 수 있었다. 또한 병렬로 구동함으로서 압전 변압기의 출력 임피던스를 감소시키므로 단일 구동시보다 최대 효율을 나타내는 부하 저항이 감소하였고 100[$k\Omega$]에서 91[%]정도를 나타내었다.

  • PDF

Stress-Strain Behavior and Electrical Resistive of Conductive Silver Particle/Silicone Composite Pastes with Surface Modification (표면처리에 따른 도전성 은입자/실리콘 복합 페이스트의 응력-변형율 거동 및 전기비저항 특성)

  • 이건웅;방대석;박민;조동환
    • Composites Research
    • /
    • v.17 no.5
    • /
    • pp.61-67
    • /
    • 2004
  • This paper reports the electrical conductivity and the stress-strain behavior of silver particle-filled silicone composite pastes for electromagnetic interference (EMI) shielding gasket materials. The percolation threshold (critical concentration) of the composite paste obtained by incorporating irregular sphere-shaped silver particles and room temperature vulcanizing (RTV) silicone resin was determined from the electrical conductivity result. At about 28 vol% Beading of untreated silver particles, the percolation phenomenon occurred and at this critical concentration, the volumetric resistivity, the tensile strength, and the elongation of the pastes were investigated. This work also suggests that the stress-strain characteristics of a composite paste filled with metal particles above the percolation threshold may be effectively improved by properly selecting a coupling agent.

Investigation of fault in the Kyungju Kaekok-ri area by 2-D Electrical Resistivity Survey (2차원 전기비저항 탐사를 이용한 경주 개곡리 지역의 단층조사)

  • Lee, Chi-Seop;Kim, Hee-Joon;Kong, Young-Sae;Lee, Jung-Mo;Chang, Tae-Woo
    • Geophysics and Geophysical Exploration
    • /
    • v.4 no.4
    • /
    • pp.124-132
    • /
    • 2001
  • Electrical resistivity survey has been conducted for delineating geological fault structure in Kaekok-ri near Kyungju. In general, electrical resistivity survey has an advantage of searching buried faults and its traces compared with other geophysical survey methods. Distribution of electrical conductivity in the ground is influenced by the ratio of pores, groundwater and clay minerals. These properties are evidenced indirectly to explain for weathering condition, faults and fracture Bones. Thus the electrical resistivity survey can be an effective method to find buried faults. We have carried out two dimensional (2-D) interpretation by means of smoothness-constrained least-squares and finite element method. Field data used in this paper was acquired at Kaekok-ri, Wuedong-eup, Kyungju-si, where is Ulsan Fault and is close to the region in which debatable quaternary fault traces were found recently. The dipole-dipole array resistivity survey which could show the 2-D subsurface electrical resistivity structure, was carried out in the area with three lines. The results showed good property of fault, fracture zone and fault traces which we estimated were congruous with the results. Through this study, 2-D electrical resistivity survey interpretation for fault is useful to apply.

  • PDF

Characteristics for Reinforcement Corrosion and Chloride Ion Diffusion of High Volume Fly Ash Concrete (하이볼륨 플라이애시 콘크리트의 철근부식 및 염소이온 확산 특성)

  • Kwon, Soon-Oh;Bae, Su-Ho;Lee, Hyun-Jin;Jung, Sang-Hwa
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.2 no.1
    • /
    • pp.34-39
    • /
    • 2014
  • The purpose of this experimental research is to evaluate the resistance of reinforcement corrosion and chloride ion penetration of high volume fly ash (HVFA) concrete. For this purpose, concrete test specimens were made for various strength level and replacement ratio of fly ash, and then compressive strength and diffusion coefficient for chloride ion of them were measured for 28, 91 and 182 days, respectively. Also, corrosion monitoring by half cell potential method was carried out for the made lollypop concrete test specimens to detect the time of corrosion initiation for reinforcement in concrete. As a result, it was observed from the test results that compressive strength of HVFA concrete was decreased with increasing replacement ratio of fly ash but long-term resistance against reinforcement corrosion and chloride ion penetration of that was increased.

Development of Optical Frequency Modulated Fiber Optic Interferometric Sensor (광주파수 변조 광섬유 간섭형 센서의 개발)

  • Kwon, Il-Bum;Kim, Chi-Yeop;Kim, Min-Soo;Lee, Wang-Joo
    • Journal of Sensor Science and Technology
    • /
    • v.9 no.3
    • /
    • pp.163-170
    • /
    • 2000
  • Optical frequency modulated fiber optic interferometric sensor was developed to sense the mechanical quantities, such as displacement, strain, force etc. It has been difficult to distinguish whether the increase of the mechanical quantities or the decrease of the quantities measured by the conventional fiber optic interferometric sensors because their signals only have a sinusoidal wave pattern related to the change of mechanical quantities. In this study, in order to measure the mechanical quantifies with the distinction of the changing direction of the quantities, the fiber of optic Michelson interferometric sensor was simply constructed by the laser light modulated with saw tooth wave pattern. The output signal of the sensor was controlled as the sinusoidal wave. The signal processing was based on the counting of the wave number of the output signal during constant time duration. The strain was determined by the cumulative value of the wave number producted by the gage factor. In order to verify the strain measurement capability of this sensor, the strain increase-decrease test was performed by universal testing machine installed with the aluminum specimen bonded with the fiber optic sensor and electrical strain gage. In the result of the test, the strain from the fiber optic sensor had a good agreement with the values from the electrical strain gage.

  • PDF

The effects of TCO/a-Si:H interface on silicon heterojunction solar cell (실리콘 이종접합 태양전지의 TCO/a-Si:H 계면 특성 연구)

  • Tark, Sung-Ju;Kang, Min-Gu;Park, Sung-Eun;Lee, Seung-Hun;Jeong, Dae-Young;Kim, Chan-Seok;Lee, Jeong-Chul;Kim, Won-Mok;Kim, Dong-Hwan
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2009.06a
    • /
    • pp.88-88
    • /
    • 2009
  • 실리콘 이종접합 태양전지 제작을 위한 주요 요소기술 중 TCO/a-Si:H 간의 계면 특성은 태양전지 효율을 결정하는 주요 인자이다. 일반적으로 투명전도 산화막으로는 ZnO:Al 또는 ITO 가 사용되고 있으며 Zn, In, Sn, O 등의 확산과 Si원소의 확산으로 TCO/a-Si:H 계면에서 $SiO_x$가 생성되어 태양전지 충진률을 감소시키는 영향을 미친다. 따라서 본 연구에서는 TCO/a-Si 계면에서 확산을 방지 하면서 패시베이션 역할을 하는 완충층을 삽입하여 실리콘 이종접합 태양전지의 효율을 높이는 연구를 수행하였다. 완충층으로 사용된 ZnO:Al의 수소화와 Zn 박막, $TiO_2$ 박막의 전기 광학적 특성을 분석하였고 AES 분석을 통해 $SiO_x$의 생성과 각 원소의 확산정도를 분석하고, CTLM을 이용하여 TCO/완충층/a-Si 간의 접촉저항을 측정하였다. 결과적으로 완충층으로 사용된 $TiO_2$(5nm)는 광특성에 큰 감소요인 없이 전기적 특성과 접촉저항 특성이 우수하였으며, 원소들간의 확산방지층으로도 우수한 특성을 보였다. ZnO:Al의 수소화는 SIMS 분석 결과 수소원소들이 계면쪽에 위치하지 않고 표면쪽에 다수 존재함으로써 패시베이션 특성을 크게 보이지 않았으나 AZO 박막의 전기적 특성은 크게 향상 시켰다. 그밖에 완충층으로 사용된 Zn 박막은 두께가 두꺼원 질수록 접촉저항의 감소를 가져왔으나 광학적 특성이 크게 감소하면서 효율적인 광포획 특성을 가지지 못하였다. 본 연구를 통하여 TCO/a-Si:H 간의 완충층 삽입을 통해 접촉저항을 낮추고 원소간의 확산을 억제하여 계면 패시베이션 특성을 향상 시킬수 있었다.

  • PDF

Resistivity Image Reconstruction Using Interacting Dual-Mode Regularization (상호작용 이중-모드 조정방법을 이용한 저항률 영상 복원)

  • Kang, Suk-In;Kim, Kyung-Youn
    • Journal of IKEEE
    • /
    • v.20 no.2
    • /
    • pp.152-162
    • /
    • 2016
  • Electrical resistivity tomography (ERT) is a technique to reconstruct the internal resistivity distribution using the measured voltages on the surface electrodes. ERT inverse problem suffers from ill-posedness nature, so regularization methods are used to mitigate ill-posedness. The reconstruction performance varies depending on the type of regularization method. In this paper, an interacting dual-mode regularization method is proposed with two different regularization methods, L1-norm regularization and total variation (TV) regularization, to achieve robust reconstruction performance. The interacting dual-mode regularization method selects the suitable regularization method and combines the regularization methods based on computed mode probabilities depending on the actual conditions. The proposed method is tested with numerical simulations and the results demonstrate an improved reconstruction performance.

Enhancement of Image Reconstruction Using Region of Interest Method Based on Adaptive Threshold Value in Electrical Impedance Tomography (전기 임피던스 단층촬영법에서 적응 문턱치 기반의 관심영역 기법을 사용한 영상 복원의 개선)

  • Kim, Chang Il;Kim, Bong Seok;Kim, Kyung Youn
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.54 no.8
    • /
    • pp.99-106
    • /
    • 2017
  • Electrical impedance tomography is a nondestructive imaging modality in which the internal resistivity distribution is reconstructed based on the injected currents and measured voltages inside a domain of interest. In this paper, an adaptive threshold value based region of interest (ROI) method is proposed to improve the spatial resolution of reconstructed images as well as to reduce the computational time of the inverse problem. Adaptive threshold value is calculated by INTERMODES method and ROI is determined from the domain based on this value. Moreover, the computational domain of image reconstruction is restricted within a ROI and iterative Gauss-Newton method is employed to estimate the resistivity distribution. To evaluate the performance of the proposed method, numerical experiments have been performed and the results are analyzed.

Comparison of Cu wafer and Disc using the electrochemical and Friction method during the CMP (Chemical Mechanical Planarization) (CMP 공정중 전기화학적 방법과 마찰력을 이용하여 Cu wafer와 Disc의 특성 비교)

  • Kang, Young-Jae;Eom, Dae-Hong;Song, Jae-Hoon;Park, Jin-Goo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2004.07b
    • /
    • pp.1300-1303
    • /
    • 2004
  • Copper는 낮은 저항률과 높은 Electromigration 저항 때문에 반도체 소자에 배선 재료로 사용된다. CMP 공정을 이용 하여 Cu wafer의 여러 가지 특성을 파악하기에는 wafer의 소모량이 많고 고가가의 비용이 예상 되므로, 본 논문에서는 비용절감을 위하여 wafer를 Disc로 대체 하고자 실험을 진행 하였고 Cu wafer와 Disc의 비료 방법은 우선 PM-5 (Genitech. co) 장비를 이용하여 removal rate의 차이점을 알 아 보았으며, 서로의 etch rate을 reomval rate과 비교하였다. EG&G 273A를 통하여 Cu wafer와 disc의 corrosion potential과 $R_p$ (Polarization resistance)값을 서로 비교 하였다. 이 논문에서는 이러한 것들을 서로 비교 하여, Cu wafer와 disc에서의 상관관계를 알고자 하였으며, 만약에 Cu wafer와 disc의 특성이 비슷하다면, Cu wafer 대신에 disc를 이용 하여 실험하여도 되는지에 관하여 조사 하였다.

  • PDF

Improvement of Electrical and Optical Properties of GZO/ITO Multi-layered Transparent Conductive Oxide Films for Solar Cells by Controlling Structure of Buffer Layer

  • Chung, Ah-Ro-Mi;Song, Pung-Keun
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2011.02a
    • /
    • pp.206-206
    • /
    • 2011
  • 투명 전도성 산화물 (TCO, Transparent Conductive Oxide) 박막을 태양전지에 적용하기 위해서는 우수한 전기 전도성 및 가시광 영역에서 높은 투과율을 가져야 한다. 대표적인 TCO 물질인 ITO (Indium tin oxide) 박막은 우수한 전기적, 광학적 특성을 가지고 있지만 $400^{\circ}C$ 이상의 고온에서는 전기저항이 급격히 증가하게 되어 실제 태양전지 패널에 적용했을 때 전기적 특성이 저하된다. 따라서 태양전지용 TCO 박막을 개발 시, 뛰어난 고온 안정성이 요구되고 있다. 본 연구에서는 고온 안정적 특성을 지니는 Ga3+를 도핑한 ZnO 계열 TCO인 GZO/ITO multi-layered 박막을 증착하였다. 또한 buffer layer의 두께 변화 및 구조 제어를 통한 최위층 박막의 전기적 특성 및 결정성을 조사하였으며 다층 박막의 계면 간 특성 및 굴절률 제어를 통한 광학적 물성을 연구하였다.

  • PDF