• 제목/요약/키워드: direct synthesis

검색결과 590건 처리시간 0.022초

Selection and Directed Evolution of New Microbial Biocatalysts and Their Application to Organic Synthesis

  • Asano, Yasuhisa
    • Journal of Applied Biological Chemistry
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    • 제43권4호
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    • pp.207-210
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    • 2000
  • As a typical example of the screening for a microbial biocatalyst from nature, isolation of nitrilesynthesizing microorganisms, characterization of a new enzyme aldoxime dehydratase, and its function in the aldoxime-nitrile pathway are introduced. Catalytic properties of some of our enzymes were improved through a direct evolutionary approach.

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퍼지규칙에 의한 직.간접 혼합 신경망 적응제어시스템의 설계 (Design of the Combined Direct and Indirect Adaptive Neural Controller Using Fuzzy Rule)

  • 이순영;장순용
    • 한국정보통신학회논문지
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    • 제4권3호
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    • pp.603-610
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    • 2000
  • 본 논문에서는 직접 적응제어기와 간접 적응제어기를 Lyapunov 안정도 이론에 근거하여 결합하였다. 제어기는 RBF 신경망을 이용하여 구성하였으며 하중파라미터들은 적응칙에 의하여 조정되도록 하였다. 또한 시스템의 성능에 영향을 미치는 결합 가중치는 퍼지 If-THEN 규칙을 이용하여 결정되도록 하였다. 이렇게 함으로써 직접 적응제어기와 간접 적응제어기의 장점을 지니는 직 간접 혼합 신경망 적응제어기를 구성할 수 있었다. 제안한 알고리즘의 효용성을 보이기 위하여 일축 강페 로봇 매니퓰레이터를 대상으로 시뮬레이션한 결과 만족할 만한 성능을 보였다.

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자성 유체용 미분 자성 분체의 제조 (Synthetic of Magnetic Fine Powder for Oil Suspending Magnetic Fluid)

  • 이경희;이병하;이재영
    • 한국세라믹학회지
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    • 제28권2호
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    • pp.146-152
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    • 1991
  • Ultra fine and homogeneous (Ni0.4Zn0.6)Fe2O4 ferrite powders were prepared by direct-wet, Hydrothermal and coprecipitation methods. In case that specific surface areas of Ni-Zn ferrite powders were over 220㎡/g, 100㎡/g, 30㎡/g individually direct-wet, hydrothermal and coprecipitation methods. The Ni-Zn ferrite magnetic fluids of which Solvents were benzene or kerosene was prepared by making cation surfactant adsorbed on the surface of the (Ni0.4Zn0.6)Fe2O4. The results that measured dispersion and viscosity by making cation surfactant adsorbed were as follows. 1. The adsorption amount of Oleric acid be proportioned the specific surface area of powders. 2. The maximum amount of Oleric acid was 36wt% of dried powders which has 220㎡/g of specific surface area. 3. The stability of fluid by direct-wet synthesis emthod in benzene or kerosene solvent excellent.

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Synthesis and Characterization of Colorimetric Chemosensors Using New Direct Dyes

  • Heo, Eun-Yeong;Kim, Sung-Hoon;Bae, Jin-Seok
    • 한국염색가공학회:학술대회논문집
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    • 한국염색가공학회 2009년도 학술발표대회
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    • pp.162-163
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    • 2009
  • Colorimetric chemosensors are now considered as one of the most effective analytical method used in the environmental monitoring. In this study, 10 new direct dyes were synthesized to be used as colorimetric chemosensor. When metal ions such as $Al^{3+},\;Ca^{2+},\;Cd^{2+},\;Cr^{3+},\;Cu^{2+},\;Fe^{2+},\;Fe^{3+},\;Hg{^2+},\;Li^+,\;Mg^{2+},\;Na^+,\;Ni^{2+},\;Pb^{2+}\;and\;Zn^{2+}$ were added to the solutions of new dyes, the colors of the solutions were changed and can be easily detected by eyes without any expensive equipments. Some metal ions were coordinated to the new direct dyes forming complex. The experimental data and conclusions were rationalized by UV-VIS spectroscopy.

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습식 직접 합성법에 의한 세라믹(PZT) 분말의 합성 (Synthesis of Pizoceramic (PZT) Powder by Wet-direct Process)

  • 이수호;김한근;최헌일;설수덕;사공건
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1990년도 하계학술대회 논문집
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    • pp.265-268
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    • 1990
  • In this study, PZT powder prepared by the wet direct process was synthesized. As starting materials, $TiCl_4$. $ZrOCl_2{\cdot}8H_2O$ and PbO were used. Uniformly shape and fine-grained PZT powder was obtained by the wet-direct process and PZT powder was characterized by XRD, DTA analysis. The X-ray diffraotion peaks from the PZT powder were observed at 700($^{\circ}C$) or over.

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