• Title/Summary/Keyword: Cell Capacitance

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A Study of the Relationship Analysis of Power Conversion and Changed Capacitance in the Depletion Region of Silicon Solar Cell

  • Kim, Do-Kyeong;Oh, Yeong-Jun;Kim, Sang-Hyun;Hong, Kyeong-Jin;Jung, Haeng-Yeon;Kim, Hoy-Jin;Jeon, Myeong-Seok
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.4
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    • pp.177-181
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    • 2013
  • In this paper, silicon solar cells are analyzed regarding power conversion efficiency by changed capacitance in the depletion region. For the capacitance control in the depletion region of silicon solar cell was applied for 10, 20, 40, 80, 160 and 320 Hz frequency band character and alternating current(AC) voltage with square wave of 0.2~1.4 V. Academically, symmetry formation of positive and negative change of the p-n junction is similar to the physical effect of capacitance. According to the experiment result, because input of square wave with alternating current(AC) voltage could be observed to changed capacitance effect by indirectly method through non-linear power conversion (Voltage-Current) output. In addition, when input alternating current(AC) voltage in the silicon solar cell, changed capacitance of depletion region with the forward bias condition and reverse bias condition gave a direct effect to the charge mobility.

Application of Generalized Transmission Line Models to Mixed Ionic-Electronic Transport Phenomena

  • Ahn, Pyung-An;Shin, Eui-Chol;Kim, Gye-Rok;Lee, Jong-Sook
    • Journal of the Korean Ceramic Society
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    • v.48 no.6
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    • pp.549-558
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    • 2011
  • Application of a generalized equivalent circuit including the electrode condition for the Hebb-Wagner polarization in the frequency domain proposed by Jamnik and Maier can provide a consistent set of material parameters, such as the geometric capacitance, partial conductivities, chemical capacitance or diffusivity, as well as electrode characteristics. Generalization of the shunt capacitors for the chemical capacitance by the constant phase elements (CPEs) was applied to a model mixed conducting system, $Ag_2S$, with electron-blocking AgI electrodes and ion-blocking Pt electrodes. While little difference resulted for the electron-blocking cell with almost ideal Warburg behavior, severely non-ideal behavior in the case of Pt electrodes not only necessitates a generalized transmission line model with shunt CPEs but also requires modelling of the leakage in the cell approximately proportional to the cell conductance, which then leads to partial conductivity values consistent with the electron-blocking case. Chemical capacitance was found to be closer to the true material property in the electron-blocking cell while excessively high chemical capacitance without expected silver activity dependence resulted in the electron-blocking cell. A chemical storage effect at internal boundaries is suggested to explain the anomalies in the respective blocking configurations.

Electrode of Low Impedance by Polypyrrole Addition for Supercapacitor (폴리피롤 첨가에 의한 supercapacitor용 저 임피던스 전극)

  • 김경민;장인영;강안수
    • Proceedings of the Safety Management and Science Conference
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    • 2003.11a
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    • pp.343-350
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    • 2003
  • The best Ppy weight ratio was 7 wt% and the optimal electrode composition ratio was 78 : 17 : 5 wt.% of (MSP-20 : BP-20 =1 : 1), (Super P : Ppy =10 : 7) and P(VdF-co-HFP). Implantation of Ppy as the conducting agents have led to superior electrochemical characteristics because of the low of internal resistance and faradaic capacitance. The result of unit cell with Ppy 7 wt% were as follows: 28.02 Fig of specific capacitance, 1.34 Ω of DC-ESR and 0.36 Ω of AC-ESR. Unit cell showed a good stability up to 200 charge-discharge cycles, retaining 82% of their original capacity at 200 cycles. From the analysis of impedance, the electrodes with Ppy 7 wt% showed low ESR, low charge transfer resistance and quick reaction rate. It was inferred that quick charge-discharge was possible. As compared with the specific capacitance (rectangular shape) of CV, it was also concluded that the specific capacitance originated from thecompound phenomena of the faradaic capacitance by oxidation and reduction of Ppy and the non-faradaic capacitance by adsorption-desorption of activated carbon.

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A Study on Capacitance Enhancement by Hemispherical Grain Silicon and Process Condition Properties (Hemispherical Grain Silicon에 의한 정전용량 확보 및 공정조건 특성에 관한 연구)

  • 정양희;정재영;이승희;강성준;이보희;유일현;최남섭
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.4
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    • pp.809-815
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    • 2000
  • The box capacitor structure with HSG-Si described here reliably achieves a cell capacitance of 28fF with a cell area of a $0.4820\mum^2$ for 128Mbit DRAM. An HSG-Si formation technology with seeding method, which employs Si2H6 molecule irradiation and annealing, was applied for realizing 64Mbit and larger DRAMS. By using this technique, grain size controlled HSG-Si can be fabricated on in-situ phosphorous doped amorphous silicon electrodes. The HSG-Si fabrication technology achieves twice the storage capacitance with high reliability for the stacked capacitors.The box capacitor structure with HSG-Si described here reliably achieves a cell capacitance of 28fF with a cell area of a $0.4820\mum^2$ for 128Mbit DRAM. An HSG-Si formation technology with seeding method, which employs Si2H6 molecule irradiation and annealing, was applied for realizing 64Mbit and larger DRAMS. By using this technique, grain size controlled HSG-Si can be fabricated on in-situ phosphorous doped amorphous silicon electrodes. The HSG-Si fabrication technology achieves twice the storage capacitance with high reliability for the stacked capacitors.

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A Study on the Extraction of Cell Capacitance and Parasitic Capacitance for DRAM Cell Structures (DRAM 셀 구조의 셀 캐패시턴스 및 기생 캐패시턴스 추출 연구)

  • Yoon, Suk-In;Kwon, Oh-Seob;Won, Tae-Young
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.37 no.7
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    • pp.7-16
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    • 2000
  • This paper reports a methodology and its application for extracting cell capacitances and parasitic capacitances in a stacked DRAM cell structure by a numerical technique. To calculate the cell and parasitic capacitances, we employed finite element method (FEM), The three-dimensional DRAM cell structure is generated by solid modeling based on two-dimensional mask layout and transfer data. To obtain transfer data for generating three-dimensional simulation structure, topography simulation is performed. In this calculation, an exemplary structure comprising 4 cell capacitors with a dimension of $2.25{\times}1.75{\times}3.45{\mu}m^3$, 70,078 nodes with 395,064 tetrahedra were used in ULTRA SPARC 10 workstation. The total CPU time for the simulation was about 25 minutes, while the memory size of 201MB was required. The calculated cell capacitance is 24.34fF per cell, and the influential parasitic capacitances in a stacked DRAM cell are investigated.

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Theoretical Analysis of Phase Detector Technique for the Measurement of Cell Membrane Capacitance During Exocytosis (세포외 분비시 막 캐패시턴스를 측정하기 위한 위상감지법(phase detector technique)의 이론적 분석.)

  • Cha, Eun-Jong;Goo, Yong-Sook;Lee, Tae-Soo
    • Progress in Medical Physics
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    • v.3 no.2
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    • pp.43-57
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    • 1992
  • Phase detector techique provides a unique probe to membrane recycling phenomenon by enabling dynamic monitoring of cell membrane capacitance. However, it has inherent errors due to constant changes in measurement environments. The present study analyzed several error sources to develope application criteria of this technique. and the following was found based on a theoretical analysis. The initial phase angle has to be appropriately selected to minimize the error due to perturbation of access and membrane conductances. Excitation frequency is also important to determine the initial phase angle. However. deviation of the phase angle from a predetermined initial value during the measurement period does not affect capacitance estimation to a significant degree. Despite an appropriate initial phase selection an error in scaling factor is expected for a large increase in capacitance during exocytosis. which may be overcome by iteratively correcting the scaling factor over the measurement period. These results will provide a useful guideline in practical application of this technique.

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Linear Correlation between Online Capacitance and Offline Biomass Measurement up to High Cell Densities in Escherichia coli Fermentations in a Pilot-Scale Pressurized Bioreactor

  • Knabben, Ingo;Regestein, Lars;Schauf, Julia;Steinbusch, Sven;Buchs, Jochen
    • Journal of Microbiology and Biotechnology
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    • v.21 no.2
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    • pp.204-211
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    • 2011
  • To yield high concentrations of protein expressed by genetically modified Escherichia coli, it is important that the bacterial strains are cultivated to high cell density in industrial bioprocesses. Since the expressed target protein is mostly accumulated inside the E. coli cells, the cellular product formation can be directly correlated to the bacterial biomass concentration. The typical way to determine this concentration is to sample offline. Such manual sampling, however, wastes time and is not efficient for acquiring direct feedback to control a fedbatch fermentation. An E. coli K12-derived strain was cultivated to high cell density in a pressurized stirred bioreactor on a pilot scale, by detecting biomass concentration online using a capacitance probe. This E. coli strain was grown in pure minimal medium using two carbon sources (glucose and glycerol). By applying exponential feeding profiles corresponding to a constant specific growth rate, the E. coli culture grew under carbon-limited conditions to minimize overflow metabolites. A high linearity was found between capacitance and biomass concentration, whereby up to 85 g/L dry cell weight was measured. To validate the viability of the culture, the oxygen transfer rate (OTR) was determined online, yielding maximum values of 0.69 mol/l/h and 0.98mol/l/h by using glucose and glycerol as carbon sources, respectively. Consequently, online monitoring of biomass using a capacitance probe provides direct and fast information about the viable E. coli biomass generated under aerobic fermentation conditions at elevated headspace pressures.

Complex Capacitance Analysis of Impedance Data and its Applications (임피던스 복소캐패시턴스 분석법의 이론 및 응용)

  • Jang, Jong-Hyun;Oh, Seung-Mo
    • Journal of the Korean Electrochemical Society
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    • v.13 no.4
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    • pp.223-234
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    • 2010
  • In this review, the theory and applications of the complex capacitance analysis, which can be utilized in analyzing capacitor-like electrochemical systems, were summarized. Theoretically, it was suggested that the imaginary capacitance plots (Cim vs. log f) can provide a simple way to analyze electrochemical characteristics of capacitive systems, without complicated mathematical calculations. The usefulness of the complex capacitance analysis has been demonstrated by applying it to analyze EDLC characteristics of practical porous carbon electrodes, ionic conductivities inside small pores, and ionic resistances in the catalyst layers of polymer electrolyte membrane fuel cells.

Quantification of Rockwool Substrate Water Content using a Capacitive Water Sensor (정전용량 수분센서의 배지 함수량 정량화)

  • Baek, Jeong-Hyeon;Park, Ju-Sung;Lee, Ho-Jin;An, Jin-Hee;Choi, Eun-Young
    • Journal of Bio-Environment Control
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    • v.30 no.1
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    • pp.27-36
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    • 2021
  • A capacitive water sensor was developed to measure the capacitance over a wide part of a substrate using an insulated electrode plate (30 cm × 10 cm) with copper and Teflon attached on either side of the substrate. This study aimed to convert the capacitance output obtained from the condenser-type capacitance sensor into the substrate water content. The quantification experiment was performed by measuring the changes in substrate water weight and capacitance while providing a nutrient solution and by subsequently comparing these values. The substrate water weight and capacitance were measured every 20 to 30 seconds using the sensor and load cell with a software developed specifically for this study. Using a curve-fitting program, the substrate water content was estimated from the output of the capacitance using the water weight and capacitance of the substrate as variables. When the amount of water supplied was increased, the capacitance tended to increase. Coefficient of variation (CV) in capacitance according to the water weight in substrate was greater with the 1.0 kg of water weight, compared with other weights. Thus, the fitting was performed with higher than 1.0 kg, from 1.7 to 6.0 kg of water weight. The correlation coefficient between the capacitance and water weight in substrate was 0.9696. The calibration equation estimated water content from the capacitance, and it was compared with the substrate water weight measured by the load cell.