• 제목/요약/키워드: Synthesis optimization

검색결과 411건 처리시간 0.032초

Combinatorial Synthesis and Screening of the $Eu^{2+}$-activated Phosphors for LED in the System CaO-$Al_2O_3-SiO_2$

  • Park, Seung-Hyok;Yoon, Ho-Shin;Kim, Chang-Hae;Jang, Ho-Gyeom
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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    • pp.647-649
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    • 2004
  • We have synthesized phosphor in the system CaO-$Al_2O_3-SiO_2$ by combinatorial polymerized-complex method. The application of combinatorial synthesis and characterization of luminescent materials has been enlarged to identification and optimization in interesting new phosphor. In this study, we investigated luminescent properties of above-mentioned materials by excitation and emission spectra. In $Eu^{2+}$ activated $Ca_1Al_2Si_2O_8$ phosphor emit the blue light.

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Synthesis of 2-Thio-4-aminopyrimidine Derivatives as Anti-cancer Agent

  • Lee, Sang-Hyo;Lee, Jin-Ho
    • 대한의생명과학회지
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    • 제15권2호
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    • pp.105-112
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    • 2009
  • The screening of the anti-cancer activity of the chemical library provided 2-thio-4-aminopyrimidine as the initial hit. The confirmation of structure and biological effect of hit was performed by synthesis and biological evaluation. The optimization of hit was performed by derivatization of substituents while keeping the core structure. The evaluation of growth inhibitory activity was carried out using SRB assay against 6 human cancer cell lines and human fibroblast. The growth inhibitory activity of compounds showed substituent dependency and more than 5 compounds showed complete growth inhibition of cancer cell lines at 10 ${\mu}M$ concentration. Chemical library screening followed by synthetic modification provided possibility that 2-thio-4-aminopyrimidine can be used as a new scaffold for the development of anti-cancer agent.

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코퍼스기반 음성합성기의 데이터베이스 최적화 방안 (An Optimization of Speech Database in Corpus-based speech synthesis sytstem)

  • 장경애;정민화
    • 대한음성학회:학술대회논문집
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    • 대한음성학회 2002년도 11월 학술대회지
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    • pp.209-213
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    • 2002
  • This paper describes the reduction of DB without degradation of speech quality in Corpus-based Speech synthesizer of Korean language. In this paper, it is proposed that the frequency of every unit in reduced DB should reflect the frequency of units in Korean language. So, the target population of every unit is set to be proportional to their frequency in Korean large corpus(780K sentences, 45Mega phonemes). Second, the frequent instances during synthesis should be also maintained in reduced DB. To the last, it is proposed that frequency of every instance should be reflected in clustering criterion and used as criterion for selection of representative instances. The evaluation result with proposed methods reveals better quality than using conventional methods.

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차패턴을 갖는 선전원 배열 안테나 합성을 위한 새로운 방법 (A New Method for Synthesis of Line Source Array Antennas with Difference Patterns)

  • 송창현;전상재;박의준
    • 한국전자파학회:학술대회논문집
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    • 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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    • pp.357-360
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    • 2005
  • In the synthesis of the continuously distributed line source antennas with arbitrary patterns, the formulas of Taylor sum pattern and Bayliss difference pattern have been mainly used. In this paper, an optimization scheme is newly presented to directly synthesize the desired difference patterns from Taylor line source formula, and then the distributions are numerically adapted to the specified difference patterns by using an appropriate iterative sampling method.

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$H_\infty$ 제어기법을 적응한 다중비 필터 뱅크의 설계 (A Design of Mutirate Filter flanks using Un Control Approach)

  • 이상철;박종우;박계원
    • 한국정보통신학회논문지
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    • 제5권6호
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    • pp.1089-1093
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    • 2001
  • 다중비 필터뱅크의 합성 필터 선계 문제에 H$\infty$ 제어기법을 적용한다. 순수한 시간 지연 시스템을 기준 모델로 설정하여 이 지연 시스템과 다중비 필터 뱅크와의 오차 시스템을 고려한다. 설계 하고자 하는 합성 필터는 오차 시스템의 ι$_2$-유도된 노름을 최소화하도록 설계한다.

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Thermal Chemical Vapor Deposition of Graphene Layers

  • Kwon, Kyoeng-Woo;Do, Woo-Ri;Hwang, Jinha
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.644-644
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    • 2013
  • Graphene is a two-dimensional sp2 layer material. Despite the short history in the empirical synthesis of the graphene layers, the academic/industrial unique features have brought highly significant interest in research and development related to graphene-related materials. In particular, the electrical and optical performances have been targeted towards pre-existing microelectronicand emerging nanoelectronic applications. The graphene synthesis relies on a variety of processing factors, such as temperature, pressure, and gas ratios involving H2, CH4, and Ar, in addition to the inherent selection of copper substrates. The current work places its emphasis on the role of experimental factors in growing graphene thin films. The thermally-grown graphene layers are characterized using physical/chemical analyses, i.e., four point resistance measurements, Raman spectroscopy, and UV-Visible spectrophotometry. Ultimately, an optimization strategy is proposed in growing high-quality graphene layers well-controlled through empirical factors.

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Optimization of Expression Conditions Enhances Production of Sepiapterin, a Precursor for Tetrahydrobiopterin Biosynthesis, in Recombinant Escherichia coli

  • Park, Eun-Hee;Lee, Won-Heong;Jang, Mi-Hee;Kim, Myoung-Dong
    • Journal of Microbiology and Biotechnology
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    • 제25권10호
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    • pp.1709-1713
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    • 2015
  • Sepiapterin is a precursor for the synthesis of tetrahydrobiopterin (BH4), which is a wellknown cofactor for aromatic amino acid hydroxylation and nitric oxide synthesis in higher mammals. In this study, a recombinant Escherichia coli BL21(DE3) strain harboring cyanobacterial guanosine 5’-triphosphate cyclohydrolase 1 (GCH1) and human 6-pyruvoyltetrahydropterin synthase (PTPS) genes was constructed to produce sepiapterin. The optimum conditions for T7 promoter–driven expression of GCH1 and PTPS were 30℃ and 0.1 mM isopropyl-β-D-thioglucopyranoside (IPTG). The maximum sepiapterin concentration of 88.1 ± 2.4 mg/l was obtained in a batch cultivation of the recombinant E. coli, corresponding to an 18-fold increase in sepiapterin production compared with the control condition (37℃ and 1 mM IPTG).

정적출력궤환 $H_2$$H_{\infty}$ 제어기 설계 (Design of $H_2$ and $H_{\infty}$ static output feedback controllers)

  • 김석주;이종무;천종민;권순민;박민국
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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    • pp.2564-2566
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    • 2005
  • This paper presents an iterative linear matrix inequality (LMI) method for $H_2$ and $H_{\infty}$ optimal static output feedback (SOF) control, which is expressed in terms of LMIs subject to an additional rank condition. We propose a linear Penalty function to penalize the rank constraint so that static $H_2$ and $H_{\infty}$ synthesis results in solving a series of convex LMI optimization problems. Numerical experiments for various $H_2$ and $H_{\infty}$ SOF synthesis were performed to demonstrate the effectiveness of the proposed algorithm.

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$H_\infty$ control of contact position and force of a manipulator

  • Lee, Sangmoo;Yae, Harold
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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    • pp.440-445
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    • 1994
  • An application of H$_{\infty}$ synthesis to contact control of a manipulator is suggested. Based on computed torque linearization of a manipulator, a target dynamics for contact motion control is defined and used as a reference model. The target dynamics relates position and force errors through free motion impedance and force error compensators. The H$_{\infty}$ control synthesis is adopted to find an optimum the compensator for position tied force control in various directions of the end-effector. The optimization is performed on the augmented criteria, which trades off the sensitivity function of the errors and the input load at the joints. A design example of the compensator is provided that meets the design specifications.s.

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Sphene-Pink 안료합성 및 Malayaite 결정이 발색에 미치는 영향 (Colouring Effect of Malayaite Formation and Synthesis Sphene-Pink Pigment)

  • 이현수;이병하
    • 한국세라믹학회지
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    • 제45권3호
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    • pp.172-178
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    • 2008
  • This paper described the study of a sphene-pink pigment based on $Cr_2O_3-SnO_2-CaO-SiO_2$ system exhibits stable pink-red color at high temperature. This study is focused on the optimization of the synthesis parameter such as temperature and holding time for the formation the Malayaite crystal. Malayaite crystal is sensitively influenced by the synthesizing temperature, maintaining time and contents of substituting chromium. The crystal phases formed at different temperatures exhibits various color. The optimum temperature is suggested at $1300^{\circ}C$ for 2 h and substituting contents of Cr for Sn is 0.01 mole. The maximum substituting contents is 0.02 mole based on analysis results by XRD, FT-IR, SEM and UV-vis.