• 자원리싸이클링
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• 제7권4호
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• pp.35-42
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• 1998

오늘날 전자부품 산업에 실장기술은 크게 각광을 받고 있다. 페라이트 칩인덕터와 같이 전자부품의 소형화를 위해서는, 쉬트 적층법이나 스크린 인쇄법 등을 위하여 유기용매를 사용하는 세라믹 습식공정이 널리 사용되고 있다. 본연구에서는 물이 혼합된 용매계를 이용한 NiCuZn Ferrite(NCZF) 슬러리와 그린쉬트의 제조 및 평가에 관한 연구를 하였다. 볼밀링에 의하여 21 vol%의 NCZF 슬러리를 제조하였으며, polacrylic vinyl copolymer를 바인더로서 사용하였다. 용매로서는 isopropyl alcohol과 2-butoxy ethanol에 40∼80% 물을 혼합하여 사용하였다. 그 결과, NCZF 슬러리의 분산안정성은 입자의 정전기적 힘보다는 free polymer에 의해 나타났으며, 슬러리의 점성은 용매중의 물함량에 크게 의존하였다.

• 멤브레인
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• 제33권6호
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• pp.279-304
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• 2023

폴리벤즈이미다졸(PBI) 기반의 막은 내구성이 우수한 네트워크 구조를 가지는 구조재료로서의 우수한 강성과 더불어서 고온에서의 우수한 내열성, 우수한 기계적 및 인장 특성, 높은 유리전이온도(T_g), 물이 없는 무수 환경에서의 이온 전도성능, 산화와 화학적 내구성으로 지난 20년 동안 다양한 용도의 대중적인 막 재료로 다양한 문헌에서 보고되어 왔다. 이온 전도성 PBI 기반 막은 고온용 양이온 교환막 연료 전지(HT-PEMFC)에서 광범위하게 사용되어왔다. 또한 PBI 기반 막은 독특한 특성으로 인해 기체분리막 및 유기용매나노여과(OSN) 막 개발에서 광범위하게 사용되어왔다. 이번 리뷰에서는 고온용 연료전지, 기체분리 및 OSN 적용을 위한 다양한 유형의 PBI 기반 막의 최근 연구동향 및 적용가능성에 대해 설명하고자 한다.

• 한국환경과학회지
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• 제28권6호
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• pp.545-552
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• 2019

Tropaeolum majus, with a high decorative and food demand for vertical greening systems, has been utilized to revitalize urban agriculture. The effects of number of non-woven fabrics in a non-water environment and the adaptability of T. majus to this system were investigated. Planting ground composition of the container-type wall vertical greening system was made using non-woven fabric in one, two, three, or four layers. The results showed that the soil water content remained the highest when the non-woven fabric comprised 4 sheets. The morphological properties showed more growth with the 4 sheets than with 1, 2, and 3 sheets. In terms of physiological characteristics, chlorophyll content was mostly high in the 4 sheets, while shoot fresh weight value was in the order of 3 > 4 > 2 > 1 sheet, and root fresh weight value was in the order of 4 > 2 > 1 > 3 sheets. The dry weight of the measured values in the shoot was in the order of 4 > 3 > 2 > 1 sheet while no clear difference was found in the root of each treatment. The difference in the flowring characteristics was not different, but in evaluating the characteristics as a whole, the growth in the three layers of non-waven fabric was the best. In addition, the soil moisture contents and the growth characteristics were statistically significant as a positive correlation between the groups. Thus, greater the non-woven fabric, the higher is the adaptability of T. majus to dry stress under soil water-free conditions by maintaining soil moisture content. This showed that it represented an effective alternative as a method of vertical greening system for lower maintenance urban agriculture.

• 한국입자에어로졸학회지
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• 제8권4호
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• pp.133-141
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• 2012

A new depth filter media was designed and samples of flat sheet as well as cartridge assembly were prepared and tested to evaluate the filtration performance and compare with the commercial product. The arrangement of the depth filter media layers is important to reach the optimal filtration parameters like filter pressure drop, particle collection efficiency and dust holding capacity. Initially, both flat sheet samples of new media and commercial product have been tested using standard test units. Tests with new depth filter media cartridges of various pleat count were conducted in order to find the optimal pleat count which would represent the lowest pressure drop. These tests give an insight on how the pleat count and the assembly configuration affect the performance of the depth filter media cartridge. By comparing the samples with a commercial product we could confirm relatively high filtration performance of the sample cartridge with pleat count 150 made of new depth filter media. The cartridge with the same pleat count exhibits better performance without the outer mesh.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1253-1258
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• 2007

The media transport systems, such as printers, copy machines, facsimiles, ATMs, cameras, etc. have been widely used and being developed rapidly. In the development of those sheet-handling machineries, it is important to predict the static and dynamic behavior of the sheet with a high degree of reliability because the sheets are fed and stacked at such a high speed. Flexible media are very thin, light and flexible, so they behave in geometric nonlinearity with large displacement and large rotation but small strain. In the flexible media analysis, aerodynamic effect from the surrounding air must be included because any small force can make large deformation. In this paper, only the flexible media analysis is performed as early stage of analysis including aerodynamic effect. Through formulations and simulations for total Lagrangian(TL), updated Lagrangian (UL) and co-rotational(CR) method which are widely used for geometric nonlinear analysis, usefulness and reliability of each methods are investigated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2248-2250
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• 2000

We investigated properties of PZT composite for medical ultrasonic transducer array (briefly UTA) for medicine applications fabricated by micro pressing and dicing method. Dicing method was the fabrication process of conventional ultrasonic transducer array by dicing sintered PZT sheet. Micro pressing method was the proposed process using pressing PZT green sheet by PMMA micro mold from LIGA process. Microstructures, electrical and electro -mechanical properties of fabricated UTAs of two cases were analyzed. Thickness mode electro-mechanical coupling coefficient of two cases have same values of 51%. Sintered PZT Microstructures of them showed dense and uniform. Micro pressing method was very mass productive process because of using batch type LIGA process. From results, we found micro pressing method was more competitive than dicing method for UTA fabrication. For further study, uniformity of microstructures and electro-mechanical properties of large scale, and fabrication processes of Ni plating and PMMA molding should be improved and investigated.

• 한국세라믹학회지
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• 제31권4호
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• pp.427-435
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• 1994

Cu-metallized low firing temperature substrates were synthesized by cofiring green sheet of cordierite-based glass with Cu. By Sol-Gel method, Cu powder was coated with borosilicate gel which should act as a glass frit in Cu paste during cofiring. Theoretical weight ratios of Glass/Cu were controlled to be 2.5, 5, 10 and 15% by varying alkoxide concentrations. Average particle size of coated Cu was 0.629~0.674 ${\mu}{\textrm}{m}$ in comparison to that of as-received Cu(0.596 ${\mu}{\textrm}{m}$), which increased with alkoxide concentration but did not increase above certain concentration. The weight ratios of coated layer were 2.11~5.37%. The properties of Cu-metallized low firing temperature substrate, cofired at 90$0^{\circ}C$ for 1h under H2/N2 atmosphere, were as follows; sheet resistance was 13~43 m{{{{ OMEGA }}/$\square$, adhesion strength was 1.0~2.1 kgf/$\textrm{mm}^2$. From the observations of SEM photographs, the gel coated on Cu performed excellently as a glass frit.

• 한국전기전자재료학회논문지
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• 제30권11호
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• pp.683-687
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• 2017

We investigated the structure of an ultra-thin insulating board with low thermal conductivity along z-axis, which was based on the idea of void layers created during the glass infiltration process for the zero-shrinkage low-temperature co-fired ceramic (LTCC) technology. An alumina and four glass powders were chosen and prepared as green sheets by the tape casting method. After comparison of the four glass powders, bismuth glass was selected for the experiment. Since there is no notable reactivity between alumina and bismuth glass, alumina was selected as the supporting additive in glass layers. With 2.5 vol% of alumina powder, glass green sheets were prepared and stacked alternately with alumina green sheet to form the 'alumina/glass (including alumina additive)/alumina' structure. The stacked green sheets were sintered into an insulating substrate. Scanning electron microscopy revealed that the additive alumina formed supporting bridges in void layers. The depth and number of the stacking layers were varied to examine the insulating property. The lowest thermal conductivity obtained was 0.23 W/mK with a $500-{\mu}m-thick$ substrate.

• 한국건축시공학회지
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• 제16권2호
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• pp.125-131
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• 2016

도심지 건물의 증가는 친환경 공간에 대한 요구를 발생시키고, 이에 따라 옥상 및 인공지반 녹화의 보급이 급속히 증가되고 있다. 본 연구는 녹화시스템의 보급 확대를 위해 공법의 단순화, 일체화, 프리훼브화 개념을 적용, 연속 토양층 형성 박스 유닛형 녹화시스템을 개발하고, 이 시스템의 주요 성능으로 부착성, 내풍성, 단열성을 평가하여 적용 가능성을 검토하였다. 부착성 및 내풍성 시험결과, 설계 풍압 및 풍속과 비교하면 100m 높이의 건물에 설치해도 안전한 것을 확인하였고, 단열성 평가를 위해 120일간 측정한 내부 온도의 변화를 분석한 결과, 개발 시스템이 연속된 토양층을 형성하여 기존 유닛박스 시스템보다 주간은 17%, 야간은 45% 우수한 단열성능을 보여 주었다.

• 한국환경복원기술학회지
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• 제4권4호
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• pp.19-24
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• 2001

숙근초화의 뗏장 생산에 적합한 초종과 바닥재를 선발하기 위해서 동자꽃, 톱풀, 큰꿩의비름, 섬기린초 등 자생식물 10종을 포함한 숙근초화류 14종의 뗏장 형성여부를 살펴보았다. 1. 재식장소에 따라서는 일반적으로 포트에 이식하여 노지에 정식하였을 경우보다 바크(bark)에 정식하였을 때 생육이 좋은 경향이었다. 2. 사용 바닥재의 종류에 따라서는 일반적으로 부직포에서 지면을 완전 피복할 때까지 걸리는 소요일수가 짧아지며, 뗏장형성능력이 좋았다. 특히 황마를 바닥재로 사용하였을 경우에는 기판이 부패하여 바크와 뿌리의 결속력이 크게 떨어지는 것을 볼 수 있었다. 3. 백리향, 좀씀바귀, 땅채송화, 바위채송화 등 포복성식물들은 꿩의비름, 애기개미취 섬쑥부쟁이 등의 직립성 초종에 비해 초고가 낮고 피복성이 좋은 것으로 나타났다.