• Title/Summary/Keyword: Activation parameters

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Output-Feedback Control of Uncertain Nonlinear Systems Using Adaptive Fuzzy Observer with Minimal Dynamic Order

  • Park, Jang-Hyun;Huh, Sung-Hoe;Park, Gwi-Tae
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.39.2-39
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    • 2001
  • This paper describes the design of an output-feedback controller based on an adaptive fuzzy observer for uncertain single-input single-output nonlinear dynamical systems. Especially, we have focused on the realization of minimal dynamic order of the adaptive fuzzy observer. For the purpose, we propose a new method in which no strictly positive real(SPR) condition is needed and combine dynamic rule activation scheme with on-line estimation of fuzzy parameters. By using proposed scheme, we can reduce computation time, storage space, and dynamic order of the adaptive fuzzy observer ...

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Kinetics of the Solvolysis of Benzyl Bromides in Alcohols (브롬화벤젠의 알코올에 의한 용매분해에 관한 반응속도론적 연구)

  • Yong-Jin Lim;Soo-Dong Yoh;Soon-Yung Hong
    • Journal of the Korean Chemical Society
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    • v.15 no.5
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    • pp.219-222
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    • 1971
  • The kinetics of the solvolysis of benzyl and p-or m-substituted benzyl bromides in various alcohols have been determined by an electric conductivity method. From these reactions, a curved Hammett plot is obtained and a mechanism is proposed to account for the nonlinear behavior observed. In addition, effects of solvent polarity on the activation parameters for the solvolysis of benzyl bromides are discussed.

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Direct Substitution Reaction of Phenylethyl Bromides

  • Jeong, Woon-Sou
    • Nuclear Engineering and Technology
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    • v.5 no.1
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    • pp.26-29
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    • 1973
  • Halongen exchange reactions of phenylethyl bromides have been studied in acetone at 25$^{\circ}$and 35$^{\circ}C$. Results show that the reaction proceeds by a typical S$_{N}$2 path, and steric crowding effect in 1-phenylethyl bromide gives large variation in the activation parameters for chloride exchange.

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Solvolysis of Phenylacetyl Chlorides in Methanol-Acetonitrile Mixtures

  • Lee Ikchoon;Huh Chul;Lee Hai Whang
    • Bulletin of the Korean Chemical Society
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    • v.10 no.1
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    • pp.47-50
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    • 1989
  • The methanolysis reactions of phenylacetyl chlorides have been investigated in methanol-acetonitrile mixtures at temperatures ranging - $15.0-0.0^{\circ}C.$ Substituent and solvent effects on the rate supported an associative $S_N2$ mechanism for the solvolysis. Activation parameters indicated that the reaction is entropy controlled, while the a/s ratios of the Taft's solvactochromic correlation proved to be remarkably constant with a typical value of 0.50 that is consistent for the reactions proceeding by a typical $S_N2$ path.

Peroxy Acid Oxidations: A Kinetic and Mechanistic Study of Oxidative Decarboxylation of $\alpha$-Keto Acids by Peroxomonophosphoric Acid

  • Radhasyam Panda
    • Bulletin of the Korean Chemical Society
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    • v.22 no.8
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    • pp.909-913
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    • 2001
  • The kinetics of oxidative decarboxylation of pyruvic acid and benzoylformic acid by peroxomonophosphoric acid (PMPA) in aqueous medium have been investigated. The reaction follows second order-first order each in PMPA and substrate concentration a t constant pH. The reactivity of different peroxo species in the oxidation has been determined. Activation energy and thermodynamic parameters have been computed. A plausible mechanism consistent with the observed results is proposed.

$^{13}C$ NMR Studies of the Chelate Ring Opening-Closing Process in (Nitrilotriacetato)vanadate(V) dioxovandate(V) Ion

  • Lee, Man-Ho;Schaumburg, Kjeld
    • Bulletin of the Korean Chemical Society
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    • v.11 no.5
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    • pp.399-402
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    • 1990
  • Activation parameters of the exchange between two types of glycinate groups in (nitrilotriacetato)dioxovanadate(V) ion, $[VO_2(NTA)]^{2-}$, have been determined as the results of $^{13}C$ NMR measurements over a range of temperatures between 277 and 306$^{\circ}K$. The exchange mechanism is proposed on the basis of the chelate ring opening-closing process, assuming rupture of the metal-oxygen (glycinate) bond trans to V = O bond to give a five-coordinated intermediate.

Chemistry of Ruthenium Hydridonitrosyl Complexes Containing Chelating Triphosphines III-Structure and Fluxional Mechanism of fac-RuH(NO)(ttp)

  • Ik Mo Lee;Yeoug Joong Kim;Ook Jae Cho;Devon W. Meek
    • Bulletin of the Korean Chemical Society
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    • v.13 no.5
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    • pp.504-507
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    • 1992
  • fac-RuH(NO)(ttp) is fluxional in the range between 180 K and 303 K. The structures involved in this fluxional process are found to be a mixture of two square pyramids and a trigonal bipyramid from the low temperature NMR spectra and the line shape analysis using DNMR 3 program and the activation parameters of this process were determined by using the simulated data. The mechanism of this fluxional process is proposed to be a pathway known as Turnstile Rotation.

Prediction of microstructure during high temperature forming of Ti-6Al-4V alloy (Ti-6Al-4V 합금의 고온성형 시 미세조직 예측에 관한 연구)

  • 이유환;신태진;황상무;이종수
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.57-60
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    • 2003
  • The purpose of this study is to investigate the high temperature deformation behavior of Ti-6Al-4V alloy and to predict the final microstructure under given forming conditions. Equiaxed and widmanstatten of Ti-6Al-4V alloys were prepared as initial microstructure and the compression tests were performed to obtain the flow curves at high temperatures (700∼1100$^{\circ}C$) and various strain rates (10$\^$-4/∼10$^2$/s). Form the results of compression test various parameters such as strain rate sensitivity (m) and activation energy (Q) were calculated and used to establish constitutive equations. To predict the final microstructure after forming, finite element analysis was performed considering the microstructural parameters such as the grain size and the volume fraction of second phase.

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Linear Relationships between Thermodynamic Parameters (Part V) Critical Evaluation and Mechanistic Significances of the Relationship (熱力學函數間의 直線關係 (第 5 報) 關係式의 評價와 反應機構上의 意義)

  • Lee, Ik-Choon
    • Journal of the Korean Chemical Society
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    • v.9 no.1
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    • pp.8-15
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    • 1965
  • Justifications for the use of ${\sigma}$ and Y as independent potential energy variables in the general equation have been reviewed and some mechanistic significances of the relationship discussed. Analysis of the activation parameters for the solvolysis of benzyl chlorides in ethanol-water mixture showed that there are two distinct series of substrate constants ${\alpha}'$, which can be correlated linearly within a series with the substituent constants ${\sigma}$ conforming to the generally accepted concept of change in mechanism from $S_N1$ to $S_N2$.

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Low Writing Field on Perpendicular Nano-ferromagnetic

  • Wibowo, Nur Aji;Rondonuwu, Ferdy S.;Purnama, Budi
    • Journal of Magnetics
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    • v.19 no.3
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    • pp.237-240
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    • 2014
  • For heat-assisted magnetic recording, magnetization reversal probabilities of nano-Pt/MnSb multilayer film with perpendicular magnetic anisotropy under thermal pulse activation were investigated numerically by solving the Landau-Lifshift Gilbert Equation. Magnetic parameters of nano-Pt/MnSb multilayer were used with anisotropy energy of $3{\times}10^5$ erg/cc and saturation magnetization of 2100 G, which offer more than 10 y data stability at room temperature. Scheme of driven magnetic field and thermal pulse on writing mechanism was designed closely to real experiment. This study found that the chosen material is potential to be used as a high density magnetic storage that requires low writing field less than two-hundreds Oersted through definite heating and cooling interval. The possibility of writing data with a zero driven magnetic field also became an important result. Further study is recommended on the thickness of media and thermal pulse design as the essential parameters of the reversal magnetization.