• International Journal of Contents
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• v.6 no.4
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• pp.39-42
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• 2010

In this paper we developed density measurement equipment for Asphalt Pavement based on the electromagnetic capacitance. This kind of Non-Nuclear Density Gauges technology and products is used or studied in USA, Finland, Sweden as standardization of authorized method for pavement density measurement. Effective permitivity of pavement asphalt is characterized in electromagnetic capacitance by the asphalt material, mixed ratio, and harden grade of pavement asphalt. We can get a density value of asphalt by replacing value of electromagnetic capacitance with standard density value and characteristic transformation curve. We are conformed that measurement data according to temperature, humidity, and real field asphalt of our density measurement equipment can be a precise value.

• Journal of the Korean institute of surface engineering
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• v.30 no.1
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• pp.44-56
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• 1997

Influence of electrochemical etching conditions on capacitance gain of aluminium electrolytic on capacitor foil has been investigated by etching cubic textured high purity aluminum foil in dilute hydrochloric acid. Uniformly distributed etch pit tunnels on aluminum surface have been obtained by pretreatment aluminium foil in 10% NaOH solution for 5 minutes followed by electrochemical etching. Electrostatic capacitance of etched aluminium foil anodized to high voltage increased with the increase of current density, total charge, temperature and concentration of electrolyte up to maximum CV-value and then deceased. Election optical observation of the etched foil revealed that the density of etch of etch pits increased with the increase of current density and concentration of electrolyte. this increase of etch pit density enlarged of the increase of capacitance. However, abnormal high current density and high electrolyte concentration induced the local dissolution of the foil surface which resulted the decrease of foil capacitance.

• JSTS:Journal of Semiconductor Technology and Science
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• v.1 no.3
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• pp.189-192
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• 2001

A simple metal-insulator-metal (MIM) capacitor in a standard $0.25{\;}\mu\textrm{m}$ digital CMOS process is described. Using all six interconnect layers, this capacitor exploits both the lateral and vertical electrical fields to increase the capacitance density (capacitance per unit area). Compared to a conventional parallel plate capacitor in the four upper metal layers, this capacitor achieves lower parasitic substrate capacitance, and improves the capacitance density by a factor of 4. Measurements and an extracted model for the capacitor are also presented. Calculations, model and measurements agree very well.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.4
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• pp.1-6
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• 2005

Recently embedded passive technology which fabricate passive elements such as resistors and capacitors at the inner layer of PCB(Printed Circuit Board) is used to make high performance IT products. However, embedded capacitor has limit in full range circuit applications because of the low capacitance density. In this paper, a new embedded capacitor which has wrinkled electrodes and dielectric layer was proposed to overcome the limits. FEM(Finite Elements Method) technique was used to evaluate capacitance density of the wrinkled type embedded capacitor. Capacitance density of the wrinkled type embedded capacitor is larger than that of conventional planar type embedded capacitor by about 25.6%$\sim$39.6%. In case of thin film type embedded capacitor, proposed wrinkled structure has more enhanced effect on the capacitance density.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.8
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• pp.650-657
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• 1989

The conversion efficiency of an ozone generator can be significantly improved by modifying the discharge electrode of a helical strip line rod-to-cylinder type ozone generator to a pyramid-project-embossed rod, and by using a pulse corona discharge. Parametric studies have been carried out to obtain optimum values of peak pulse voltage, pulse forming capacitance, feeder cable and ozone generator capacitance, interelectrode spacing and corona tip density of ozone generator, and feed air flow rate and temperature. The generated ozone concentration was very dependent upon the value of pulse forming capacitance, feeder cable and ozone generator capacitance, and corona tip density. Maximum conversion efficiency was obtained with a pulse forming capacitance of about 500pF, 75pF matched feeder cable and ozone generator, and a corona tip density of 16mm. When operated at optimum values, ozone yield of 79, 99, 80 g/KWh for the different interelectrode type ozone generators tested were obtained, which are approximately 30% higher than that of an industrial ozone generator.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.279-280
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• 2006

This paper analysised Oil-Mist-Detector applied Capacitance Sensor which protects Diesel engine & human from explosion by detecting density of oil mist distribution. Assuming that distance between oil mists is same, Capacitance sensor plates & all oil mists could be analogized to capacitors. From equivalent circuit of Oil-Mist-Detector, variation of Capacitance which is related to Oil Mist's diameter & density of oil mist distribution is obtainable.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.8
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• pp.1187-1196
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• 1989

In this paper, a method for computing the capacitance parameter for a multi-interconnection line in a multilayered dielectric region is presented. The number of interconnection lines and the number of dielectric layers are arbitrary, and the interconnection lines are finite cross section or infinite cross section. The surface of lines and dielectric interface are divided into subsection. The surface charge density of each subsection is a constant step-pulse function for each subsection. After the solution of surface charge density is effected by the method of moments, capacitance parameter is calculated.

• Carbon letters
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• v.22
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• pp.70-80
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• 2017

Activated carbons (ACs) have been used as electrode materials of electric double-layer capacitors (EDLC) due to their high specific surface areas (SSA), stability, and ecological advantages. In order to make high-energy-density ACs for EDLC, petroleum pitch (PP) pre-carbonized at $500-1000^{\circ}C$ in $N_2$ gas for 1 h was used as the electrode material of the EDLC after KOH activation. As the pre-carbonization temperature increased, the SSA, pore volume and gravimetric capacitance tended to decrease, but the crystallinity and electrode density tended to increase, showing a maximum volumetric capacitance at a medium carbonization temperature. Therefore, it was possible to control the crystalline structure, SSA, and pore structure of AC by changing the pre-carbonization temperature. Because the electrode density increased with increasing of the pre-carbonization temperature, the highest volumetric capacitance of 28.4 F/cc was obtained from the PP pre-carbonized at $700^{\circ}C$, exhibiting a value over 150% of that of a commercial AC (MSP-20) for EDLC. Electrochemical activation was observed from the electrodes of PP as they were pre-carbonized at high temperatures above $700^{\circ}C$ and then activated by KOH. This process was found to have a significant effect on the specific capacitance and it was demonstrated that the higher charging voltage of EDLC was, the greater the electrochemical activation effect was.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.266-266
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• 2009

For the development of hybrid supercapacitor, increasing energy density is one of the most crucial matters. Since the energy density is the function of capacitance and voltage, it is necessary to enhance energy density for increasing capacitance or voltage. For the high working voltage, it was to enforce Li ion free-doping to activated carbon. As a result, initial capacitance has increased by 11% than raw cell. But capacitance has decreased by Li ion re-solution to electrolyte for increase the number of cycle.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.69-70
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• 2003

10 wt.% of PAN was dissolved in N,N-dimethylformamide (DMF) and 1 wt. % of the multi wall carbon nanotubes (MWCNTs) was evenly dispersed in PAN solution by using ultrasonic miner. The 1 wt.% addition of MWCNT increased the specific capacitance by two times more from 82 to 160 F/g. The specific capacitance of carbon nanofiber(CNF)/carbon nanotube(CNT) composite capacitors was about 90 F/g at the current density of 500 mA/g. This value is even larger than the capacitance from the CNF electrode at the current density of 5 mA. The relatively high capacitance at the high current density is a practical importance for applications to supercapacitor in motor vehicle.