• Title/Summary/Keyword: B-SiC

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Surface Active Properties and LCST Behavior of Oligo(propylene oxide-block-ethylene oxide) Allyl Ether Siloxane Surfactants in Aqueous Solution

  • Kim, Doo-Won;Lim, Chul-Hwan;Choi, Jae-Kon;Noh, Si-Tae
    • Bulletin of the Korean Chemical Society
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    • v.25 no.8
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    • pp.1182-1188
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    • 2004
  • Polydisperse oligo(PO-b-EO) allyl ether siloxane surfactants were synthesized by the hydrosilylation reaction of OMTS with Allyl-oligo(PO-b-EO) series. The surface tension of siloxane surfactants increased with increasing the EO chain length while it decreased with increasing the PO ratio. However, the sedimentation time of the aqueous solution showed opposite trend to the surface tension data. Both the surface tension and sedimentation time of the aqueous solution containing inorganic electrolyte gradually decreased as the content of inorganic electrolyte increased because of the surface arrangement of surfactant molecules. However, they increased with an increase of pH values due to the hydrolysis of the siloxane backbone. The $C_p$ values tended to increase with the increase in the EO chain length and decrease of the PO ratio. It seems that intermolecular interaction between PO/EO block copolymer and water affects the variation of transition temperature.

Manufacture of Ordinary Portland Cement Clinker Using Cement Paste of the Waste Concrete (폐콘크리트로부터 회수된 시멘트 페이스트 미분말의 시멘트 원료화 연구)

  • Ahn, Ji-Whan;Kim, Hyung-Seok;Cho, Jin-,Sang;Han, Gi-Chun;Han, Ki-Suk;Kim, Hwan
    • Journal of the Korean Ceramic Society
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    • v.40 no.8
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    • pp.804-810
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    • 2003
  • The fine powder produced by heating and grinding of the waste concrete in the waste construction was investigated whether utilize as substitution raw material of SiO$_2$, CaO, and Al$_2$O$_3$ source for OPC clinker manufacture is possible or not. In order to synthesize OPC clinker, limestone, shale, converter slag and fly ash were used as main raw materials, and modulus was fixed LSF 91.0, SM 2.60, IM 1.60. The synthesized clinkers were characterized. The Main products of synthesized clinker were C$_3$S, ${\beta}$-C$_2$S, C$_3$A, C$_4$AF as OPC clinker at 1,43$^{\circ}C$. As a result of TG-DTA and burnability index(B.U) analysis of each raw mixtures, the formation temperature of clinker phases was similar and B.I was showed easy burning as 48.6∼51.4.

Growth Patterns of Temperature-sensitive Mutants of Bacillus Thuringiensis (Bacillus thuringiensis 의 Temperature-sensitive Mutants 분리와 특성 연구)

  • Lee, Hyung-Hoan;Lee, Hoon-Ku
    • Microbiology and Biotechnology Letters
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    • v.11 no.3
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    • pp.233-239
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    • 1983
  • Bacillus thuringiensis was mutagenized with UV light irradiation and nitrosoguanidine. Twenty-four tem perature-sensitive ts mutants were isolated at 42$^{\circ}C$ and classified into two groups by growth on nutrient agar at 42$^{\circ}C$. First is the lethal group, which did not grow at the nonpermissive temperature, the second is the reduced group whose growth was restricted from one-half to one-fourth, Thirteen ts mutants belong to the lethal group and eleven ts mutants belong to the reduced group. Auxotrophic mutant, A-N28 required five amino acids as growth factors, A-N65 also five amino acids, A-N92 seven, A-N115 four and A-N156 three. Bacillus thuringiensis wild type is resistant to penicillin, ampicillin, and cephalothin. The ts-Ul7l, A-N92 and A-Nl15 are sensitive to the three antibiotics. The ts -U601, -U603, -U604 and -Ul71 did not grow at the permissive temperature after temperature-shifting from 42$^{\circ}C$. Four auxotrophic mutants (A-N38, A-N65, A-N92 and A-Nl15) did not form spores in their cells.

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Fabrication of Mach-Zehnder Interferometric Modulator Using Proton-Diffused Channel Waveguide (양자확산 LiNbO$_3$ 광도파로를 이용한 Mach-Zehnder 간섭계 구조의 광변조기 제작)

  • 김종성
    • Proceedings of the Optical Society of Korea Conference
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    • 1990.02a
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    • pp.264-268
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    • 1990
  • A guided-wave electro-optic Mach-Zehnder interferometric modulator was fabricated on X-cut LiNbO3 . The channel waveguides were formed by proton diffusion with self-aligned SiO2-cladding. A mach-Zehnder interferometric modulator with arm lengths of 7mm has been fabricated and tested at 0.6328${\mu}{\textrm}{m}$. Its modulation depth with V$\pi$ of only 3.5V was 85% and the 3dB bandwidth was 1.6KHz. For high speed operation, the electrode dimension should be reduced to have smaller R, L, and C.

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MoS2 monolayer에서의 doping effect

  • Lee, Mi-So
    • Proceeding of EDISON Challenge
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    • 2015.03a
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    • pp.373-377
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    • 2015
  • 이 연구에서는 원자 궤도 함수 기반 DFT 전자구조 계산을 이용해서 최근 각광받고 있는 이차원 물질인 MoS2 monolayer의 S 자리와 Mo 자리에 각각 전자가가 다른 원자를 치환하였을 때의 도핑 특성을 Density of States (DOSs)와 밴드구조 등의 전자구조를 통해 분석해 보았다. S자리에 Cl, Si, I, B, C, Mo 자리에는 Hf, Ta, 그리고 Re을 치환해 보았으며 계산 결과 S자리에 Cl을 치환했을 때 가장 얕은 acceptor level (VBM으로부터 0.08 eV)이 형성되었으며, Mo자리에 Re를 치환했을 때에는 resonant state를 형성하였다. 또한 Mo자리에 Ta를 치환했을 ? 가장 얕은 donor level (CBM으로부터 0.02 eV)가 형성되었다.

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Printed polymer and a-Si TFT backplanes for flexible displays

  • Street, R.A.;Wong, W.S.;Ready, S.E.;Chabinyc, M.L.;Arias, A.C.;Daniel, J.H.;Apte, R.B.;Salleo, A.;Lujan, R.;Ong, Beng;Wu, Yiliang
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.697-699
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    • 2005
  • The need for low cost flexible TFT display backplanes has focused attention on new processing techniques and materials. We have developed backplane technology based entirely on jet-printing, using a combination of additive and subtractive processing, and have applied this technique to both amorphous silicon and polymer TFT arrays.

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