• 마이크로전자및패키징학회지
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• 제26권2호
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• pp.23-29
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• 2019

Thermally expandable microsphere and aerogel composite was prepared by chemical compositization. Microsphere can produce synergies with aerogel, especially an enhancement of mechanical property. Through condensation between sulfonated microsphere and hydrolyzed silica sol, chemically-connected composite aerogel could be prepared. The presence of hydroxyl group on the sulfonated microsphere was observed, which was the prime functional group of reaction with hydrolyzed silica sol. Silica aerogel-coated microsphere was confirmed through microstructure analysis. The presence of silicon-carbon absorption band and peaks from composite aerogel was observed, which proved the chemical bonding between them. A relatively low thermal conductivity value of $0.063W/m{\cdot}K$ was obtained.

• 한국화재소방학회논문지
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• 제32권1호
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• pp.40-45
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• 2018

무기재로서 질석은 친환경적인 특성과 내화, 단열, 흡음 뿐 만 아니라 결로방지, 탈취 및 미관 등이 우수하므로 건축마감재로서 활용될 경우 효용성이 높을 것으로 판단된다. 본 연구에서는 질석을 주원료로 하여 미네랄 루즈울(Mineral Loose Wool) 또는 미네랄 파우더(Mineral Powder)를 혼입한 건축용 마감보드를 개발하고 불연시험과 단열시험을 수행하였다. 시험결과 두 개의 질석보드 모두 불연재로서 성능을 확보하였으며 열전도율 0.086 및 $0.092W/m{\cdot}K$로 나타났다. 또한 개발된 두 개의 질석보드를 경골목구조 내화벽체 표준상세(KS F 1611-1)의 마감재로 적용하여 내화시험을 수행하였다. 내화시험결과 VB-L 시험체가 VB-P시험체 보다 내화성능이 다소 높게 나타났으며 두 개의 질석보드 모두 두께 30 mm로도 내화성능 2시간 확보가 충분한 것으로 나타났다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.369-374
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• 2008

This study is an inorganic foaming ceramic by sol-gel reaction in order to overcome weak point of insulator using in construction equipment. We shall be able to confirm as the existing product substitute is possible result of this study. The solution where the silicate, the ceramic powder and the additive are included which makes foaming ceramic slurry, then the insulator made by used $CO_2$ Sol-Gel reaction. There being will be able to manufacture the insulator where the economical efficiency is excellent confirmed at the start product which is completed. The recording gel time decreases when the silicate will increase. Uses the hydrogen peroxide and fe make foam, when additionally surface preparation the fluorine resin, the water tolerance increases and will be able to complement the weak point of the silicate which omits in the water. The case which will use the loess powder with the research method which sees specially was environment-friendly product and according to appearing, the physical properties of nonflammability.

• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.461-466
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• 2018

The effects of Ca/Sr ratio and the sintering temperature on the properties of $(Ca_xSr_{(1-x)})ZrO_3$ (CSZ) ceramics were investigated in this study. CSZ ceramics were prepared using solid-state reaction process, which were sintered in air at temperatures ranging from $1350^{\circ}C$ to $1450^{\circ}C$. Their structures were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The change in Ca/Sr ratio significantly affected the crystalline phase and the dielectric properties of the $(Ca_xSr_{(1-x)})ZrO_3$ ceramics. The secondary phase, $Ca_{0.15}Zr_{0.85}O_{1.85}$, was observed and increased correspondingly with the rising of sintering temperatures. In order to understand the effects of secondary phase on the dielectric properties of CSZ ceramics, the $Ca_{0.15}Zr_{0.85}O_{1.85}$ phase was prepared individually using solidstate method. The $Ca_{0.15}Zr_{0.85}O_{1.85}$ ceramics sintered at $1500^{\circ}C$ for 2 hours possessed a dielectric constant (${\varepsilon}_r$) of 21.7, a dielectric loss ($tan{\delta}$) of $49.510^{-4}$ and an Insulation Resistance (IR) of $2.1{\times}10^{10}{\Omega}$. The ($Ca_{0.7}Sr_{0.3})ZrO_3$ ceramics exhibited the best dielectric properties, with a permittivity of 29, a dielectric loss ($tan{\delta}$) of $2.7{\times}10^{-4}$, and an Insulation Resistance (IR) of $2.6{\times}10^{12}{\Omega}$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.71-71
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• 2012

As the critical dimensions of integrated circuits are scaled down, the line width and spacing between the metal interconnects are made smaller. The dielectric film used as insulation between the metal lines contributes to the resistance-capacitance (RC) time constant that governs the device speed. If the RC time delay, cross talk and lowering the power dissipation are to be reduced, the intermetal dielectric (IMD) films should have a low dielectric constant. The introduction of Cu and low-k dielectrics has incrementally improved the situation as compared to the conventional $Al/SiO_2$ technology by reducing both the resistivity and the capacitance between interconnects. Some of the potential candidate materials to be used as an ILD are organic and inorganic precursors such as hydrogensilsequioxane (HSQ), silsesquioxane (SSQ), methylsilsisequioxane (MSQ) and carbon doped silicon oxide (SiOCH), It has been shown that organic functional groups can dramatically decrease dielectric constant by increasing the free volume of films. Recently, various inorganic precursors have been used to prepare the SiOCH films. The k value of the material depends on the number of $CH_3$ groups built into the structure since they lower both polarity and density of the material by steric hindrance, which the replacement of Si-O bonds with Si-$CH_3$ (methyl group) bonds causes bulk porosity due to the formation of nano-sized voids within the silicon oxide matrix. In this talk, we will be introduce some properties of SiOC(-H) thin films deposited with the dimethyldimethoxysilane (DMDMS: $C_4H_{12}O_2Si$) and oxygen as precursors by using plasma-enhanced chemical vapor deposition with and without ultraviolet (UV) irradiation.

• 한국세라믹학회지
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• 제56권3호
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• pp.211-232
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• 2019

Porous ceramics are promising materials for a number of functional and structural applications that include thermal insulation, filters, bio-scaffolds for tissue engineering, and preforms for composite fabrication. These applications take advantage of the special characteristics of porous ceramics, such as low thermal mass, low thermal conductivity, high surface area, controlled permeability, and low density. In this review, we emphasize the direct foaming method, a simple and versatile approach that allows the fabrication of porous ceramics with tailored microstructure, along with distinctive properties. The wet foam stability is achieved under the controlled addition of amphiphiles to the colloidal suspension, which induce in situ hydrophobization, allowing the wet foam to resist coarsening and Ostwald ripening upon drying and sintering. Different components, like contact angle, adsorption free energy, air content, bubble size, and Laplace pressure, play vital roles in the stabilization of the particle stabilized wet foam to the porous ceramics. The mechanical behavior of the load-displacements curves of sintered samples was investigated using Herzian indentations testes. From the collected results, we found that microporous structures with pore sizes from 30 ㎛ to 570 ㎛ and the porosity within the range from 70% to 85%.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.49-52
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• 2008

The present study was to develop a dry PFB method similar to the existing gypsum board construction method in order to apply the existing wet PFB method that uses fire-resistant adhesive. It was found that the existing wet method can produce concrete compressive strength of 80MPa and fire resistance of 3 hours with 30mm PF boards. The goal of development in this study was fire resistance of 3 hours through dry construction of 15mm fire-resistant boards. 1. Improved PF board was prepared by adding inorganic fiber to existing board and using aggregate with grain size of 3mm or less. Molding was done at temperature higher than that for existing PF board molding. While wet curing is used for existing PF boards, this study used dry curing in order to enhance heat insulation performance. 2. According to the results of fire resistance test, when the dry PF method was applied, the temperature of the main reinforcing bar was 116℃ in 15mm, 103.8℃ in 20mm, and 94℃ in 25mm, and these results satisfied the current standards for fire resistance control presented by the Ministry of Land, Transport and Maritime Affairs. When a 3-hour fire resistance test was performed and the external properties of the specimen were examined, the outermost gypsum board hardly remained and internal PF board maintained its form without thermal strain.

• 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.

• 한국전기전자재료학회논문지
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• 제31권7호
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• pp.496-501
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• 2018

In this study, we prepared 40, 45, 50, 55, 60, 65, and 70 wt% content composites filled in epoxy matrix for two micro silica and three micro alumina types for use as a GIS heavy electric machine. As a filler type of epoxy composite, micro silica composites showed excellent AC breakdown strength properties compared to micro alumina composites in the case of electrical properties of micro silica and alumina. The electrical breakdown properties of micro silica composites increased with increasing filler content, whereas those of micro alumina decreased with increasing filler content. In the case of mechanical properties, the micro silica composite showed improved tensile strength and flexural strength compared with the micro alumina composite. In addition, mechanical properties such as tensile strength and flexural strength of micro silica and alumina composites decreased with increasing filler content. This is probably because O-H groups are present on the surface of silica in the case of micro silica but are not present on the surface of alumina in the case of micro alumina.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.400-403
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• 2003

Recently, the study on development of electrical and electronic device is done to get miniature, high degrees of integration and efficiency by using inorganic materials. the study of Langmuir-Boldgett(LB) method that uses organic materials because of the limitation for the ultra small size. In this paper, detected displacement current using PBLG and PBDG, deposition and observed the electrical characteristics to each 1, 3, 5, 7, 9 layers by LB method. Maximum value of change ratio of displacement current by the detected speed and temperature appeared almost lineally, could confirm that it are in comparison relation each other speed temperature and displacement current. The structure of manufactured device is MIM. Also, we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from 0 to +2[V]. The insulation property of a thin film is better as the distance between electrodes is larger.