• 조명전기설비학회논문지
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• 제29권3호
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• pp.88-95
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• 2015

The accelerated thermal aging of CSPE(Chloro Sulfonate Polyethylene) was carried out for 40.41, 121.22, 202.04 days, 16.82, 50.45, 84.09 days and 7.32, 21.96, 36.59 days at 100, 110, and $120^{\circ}C$, respectively, which are equivalent to 20, 60, 100 years of aging at $50^{\circ}C$. The permittivities and the apparent densities of the accelerated thermally aged CSPE samples are increased with accelerated thermal aging year but EAB(Elongation at Break) is decreased with that. The dielectric strength and the electric breakdown of the non-accelerated and accelerated thermally aged CSPE samples do not depend on accelerated thermal aging year and applied voltage rising time. density and EAB measures.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2425-2433
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• 2018

This study investigates a new organic based material and its dielectric and mechanical properties. It is a comprehensive nanocomposite comprising a combination of various types of nanofillers with hydrophobic silica nanoparticles (AEROSIL R 974) as a matrix modifier and a polyamide nano nonwoven textile, Ultramid-Polyamide 6, pulped in the electrostatic field as a dielectric barrier. The polymer matrix is an epoxy network based on diglycidyl ether of bisphenol A (DGEBA) and cycloaliphatic diamine (Laromine C260). The designed nanocomposite material is an alternative to the conventional three-component composites containing fiberglass and mica with properties that exceed current electroinsulating systems (volume resistivity on the order of $10^{16}{\Omega}{\cdot}m$, dissipation factor tan ${\delta}=4.7{\cdot}10^{-3}$, dielectric strength 39 kV/mm).

• 전기학회논문지
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• 제60권5호
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• pp.984-989
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• 2011

Electrical insulation is one of the most important part in a high voltage apparatus. Recently, researchers are interested in the environmental friendly vegetable oil from environmental viewpoint. Accelerated aging transformer insulating material in vegetable oil was compared to that of mineral oil. Accelerated aging oil samples produced in the oven at $140^{\circ}C$ for 500, 1000, 1500, 2000hours. And Real transformer insulation oils samples of vegetable oil and mineral oil were aged by thermal cycles repeating from $30^{\circ}C$ to $120^{\circ}C$. Samples were analyzed at 42, 63, 93, 143, 190, 240, 300 cycles. The mineral and vegetable insulating oils were investigated for breakdown voltage, water content, total acid number, viscosity, volume resistivity, insulating paper and oil permittivity, and dissolved gas analyses. The breakdown voltage of the vegetable insulating oil is higher than that found for the mineral oil; the accelerated aging progress decreased the breakdown voltage. The vegetable oil had a higher water saturation than the mineral oil; the vegetable oil has the superior water characteristics and breakdown voltage. And high viscosity of vegetable oil, care has to be taken, especially when designing the cooling system for a large transformer.

• 한국컴퓨터산업학회논문지
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• 제3권12호
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• pp.1747-1758
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• 2002

실리콘 젤의 경화조건에 따른 전기적 특성을 조사하기 위하여 절연파괴특성에 대한 실험을 실시하였다. 실험을 위해 온도 100[$^{\circ}C$], 125[$^{\circ}C$], 150[$^{\circ}C$], 160[$^{\circ}C$], 170[$^{\circ}C$], 180[$^{\circ}C$]에서 각각 30[Min], 1[H], 2[H]동안 경화된 여러 시료를 제작하였다. 절연파괴실험에서 사용된 전극의 재료는 순도 99.9[%]의 구리이며, 전극간 간격은 1~3[mm]로 하였고, 전극의 두께는 0.2[mm]이다. 실험결과 온도 170[$^{\circ}C$]에서 2[H] 경화된 시료의 전기적 특성이 가장 우수하였다.

• 통합자연과학논문집
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• 제3권3호
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• pp.168-173
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• 2010

Novel porous silicon chip exhibiting dual optical properties, both Frbry-Perot fringe (optical reflectivity) and photoluminescence had been developed and used as chemical sensors. Porous silicon samples were prepared by an electrochemical etch of p-type sillicon wafer (boron-doped, <100> orientation, resistivity 1 - 10 ${\Omega}$). The ething solution was prepared by adding an equal volume of pure ethanol to an aqueous solution of HF (48% by weight). The porous silicon was illuminated with a 300 W tungsten lamp for the duration of etch. Ething was carried out as a two-electrode Kithley 2420 preocedure at an anodic current. The surface of porous silicon was characterized by FT-IR instrument. The porosity of samples was about 80%. Three different types of porous silicon, fresh porous silicon (Si-H termianated), oxidized porous silicon (Si-OH terminated), and surface-derivatized porous silicon (Si-R terminated), were prepared by the thermal oxidation and hydrosilylation. Then the samples were exposed to the wapor of various organics vapors. such as chloroform, hexane, methanol, benzene, isopropanol, and toluene. Both reflectivity and photoluminescence were simultaneously measured under the exposure of organic wapors.

• 통합자연과학논문집
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• 제3권3호
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• pp.153-156
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• 2010

Oxidation behaviors of porous silicon were investigated by the measurement of area of $SiO_2$ vibrational peaks in FT-IR spectra during thermal oxidation of porous silicon at corresponding temperatures. Visible photoluminescent porous silicon samples were obtained from an electrochemical etch of n-type silicon of resistivity between 1-10 ${\Omega}/cm$. The etching solution was prepared by adding an equal volume of pure ethanol to an aqueous solution of HF. The porous silicon was illuminated with a 300 W tungsten lamp for the duration of etch. Etching was carried out as a two-electrode galvanostatic procedure at applied current density of 200 $mA/cm^2$ for 5 min. The porosity of samples prepared was about 80%. After formation of porous silicon, the samples were thermally oxidized at $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$, and $400^{\circ}C$, respectively. The growth rate of $SiO_2$ layer of porous silicon was investigated by using FT-IR spectroscopy. The effect of oxidation of porous silicon was presented.

• 한국재료학회지
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• 제29권12호
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• pp.757-763
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• 2019

A stacked high-voltage (900 V) Al electrolytic capacitor made with ZrO₂ coated anode foils, which has not been studied so far, is realized and the effects of Zr-Al-O composite layer on the electric properties are discussed. Etched Al foils coated with ZrO₂ sol are anodized in 2-methyl-1,3-propanediol (MPD)-boric acid electrolyte. The anodized Al foils are assembled with stacked structure to prepare the capacitor. The capacitance and dissipation factor of the capacitor with ZrO₂ coated anode foils increase by 41 % and decrease by 50 %, respectively, in comparison with those of Al anode foils. Zr-Al-O composite dielectric layer is formed between separate crystalline ZrO₂ with high dielectric constant and amorphous Al₂O₃ with high ionic resistivity. This work suggests that the formation of a composite layer by coating valve metal oxide on etched Al foil surface and anodizing it in MPD-boric acid electrolyte is a promising approach for high voltage and volume efficiency of capacitors.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.104-104
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• 2010

With the advent of nano-particle fillers in insulating materials, the insulating materials of superior quality have come to fore. In the recent past, nanocomposite LDPE/XLPE (Low Density Polyethylene/Cross Linked Polyethylene) power cable dielectrics have been synthesized. A preliminary evaluation of these new class of materials seem to show that, addition of small amounts of sub-micron inorganic fillers improved the dielectric properties of the composite, in particular, the volume resistivity, and the DC breakdown strength. The thermal behaviour, for example, the stability of composites against decomposition and ensuing electrical failure, do not seem to have been addressed. In a conventional XLPE insulated cable, the average thermal breakdown strength and maximum temperature at the onset of breakdown were seen to be markedly lower than the corresponding intrinsic breakdown strength and decomposition temperature. In this page, analysis of DC Breakdown of nano-composite insulating material for HVDC Cable is introduced.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.233-233
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• 2010

It is important to form the n+ emitter layer for generating electric potential collecting EHP(Electron-Hole Pair). In this paper the formation on the n+ emitter layer of silicon wafer has been made with respect to uniformity of shallow diffusion from a liquid source. The starting material was crystalline silicon wafers of resistivity $0.5{\sim}3\{Omega}{\cdot}cm$, p-type, thickness $200{\mu}m$, direction[100]. The formation of n+ emitter layer from the liquid $POCl_3$ source was carried out for $890^{\circ}C$ in an ambient of $N_2:O_2$::10:1 by volume. And than each conditions are pre-deposition and drive-in time. It has been made uniformity of at least. so, the average of sheet resistance was about 0.12%. In this study, sheet resistance was measured by 4-point prove.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.153-156
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• 2005

Nondestructive sensing of electrospun PYDF web and multi-wall carbon nanotube (MWCNT)/epoxy composites were investigated using electro-micromechanical technique. Electrospinning is a technique used to produce micron to submicron diameter polymeric fibers. Electrospun PVDF web was also evaluated for the sensing properties by micromechanical test and by measurement electrical resistance. CNT composite was especially prepared for high volume contents, 50 vol% of reinforcement. Electrical contact resistivity on humidity sensing was a good indicator for monitoring as for multifunctional applications. Work of adhesion using contact angle measurement was studied to correlate acid-base surface energy between carbon fiber and CNF composites, and will study furher for interfacial adhesion force by micromechanical test.