• 제목/요약/키워드: Reaction stability

검색결과 1,612건 처리시간 0.033초

Synthesis and Characterization of Novel Fused Aromatic Semiconductors

  • Zhao, Qinghua;Park, Jong-Won;Kim, Yun-Hi;Kwon, Soon-Ki
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.1193-1197
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    • 2006
  • The novel oligomers were synthesized by Grignard reaction, the suzuki coupling reaction, etc. The oligomers were characterized by Infrared (IR), Mass spectrometer (MS). Their thermal properties were investigated by differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). The new oligomers showed high thermal stability above $300^{\circ}C$.

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다량의 붕소원소를 함유하는 식물의 중금속 이온 교환반응 (Heavy Metal Son Exchange Reaction in Boron-Rich Containing Plants)

  • 배계선;성대동
    • 한국환경과학회지
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    • 제5권6호
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    • pp.757-762
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    • 1996
  • The removal effectiveness of various heavy metal ions in boron-rich containing plants has been studied by means of spectroscopic and pH methods. Treatment of the boron-rich containing sample which was collected from cherry and root of cabbage to heavy metal ions is resulted in that an excellent removal effect shows in the case of large ionic size of heavy metal. Stability constants are depended on the variation of pH.

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GLOBAL STABILITY OF SOLUTIONS OF AN ELECTROCHEMISTRY MODEL WITH A SINGLE REACTION

  • Kim, Eu-Hee
    • 대한수학회논문집
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    • 제14권2호
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    • pp.429-440
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    • 1999
  • In this paper an electrochemistry model which consists of three charged species is considered. A dissociation-association reaction is allowed to take place between these species. The species of ions diffuse owing to concentration gradients and migrate because of electric forces. We prove that any initial distribution of species concentrations will settle down to the unique steady state as time becomes large.

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The Effect of External Noise on Dynamic Behaviors of the $Schl\ddot{o}gl$ Model with the First Order Transition fora Photochemical Reaction

  • 김경란;Lee, Dong J.;신국조
    • Bulletin of the Korean Chemical Society
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    • 제16권11호
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    • pp.1113-1118
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    • 1995
  • The Schlo'gl model with the first order transition for a photochemical reaction is considered to study the dynamic behaviors in the neighborhood of the Gaussian white noise by obtaining the explicit results of the time-dependent variance and time correlation function with the aid of approximate methods based on the stationary properties of the system. Then, we discuss the effect of external noise strength on the stability of the model at steady states in detail.

Studies on the Regioselective of Chlorosulfonyl Isocyanate with Cyclic ethers

  • Lim, Seung-Yong;Jung, Young-Hoon
    • 대한약학회:학술대회논문집
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    • 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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    • pp.183.1-183.1
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    • 2003
  • The synthesis of various cyclic carbamate compounds and amino alcohols has attracted attention in the past because of their potential as antibiotics, antitumor, analgenics, anticonvulsants. Several methods for the preparation of cyclic carbamate compounds have previously been reported including the use of heterocumulenes. We have recently described the novel synthetic method for N-protected amines from various ethers using Chlorosulfonyl isocyanate(CSI) and found that the mechanism of our CSI reaction is a competitive reaction of $S_N1$ and $S_ Ni$ mechanisms according to the stability of carbocation intermediates. (omitted)

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Hydrophobic Catalyst Mixture for the Isotopic Exchange Reaction between Hydrogen and Water

  • Paek S.;Ahn D.H.;Choi H.J.;Kim K.R.;LEE M.;YIM S.P.;CHUNG H.
    • 한국방사성폐기물학회:학술대회논문집
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    • 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
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    • pp.141-148
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    • 2005
  • Pt/SDBC catalyst, which is used for the hydrogen-water isotopic exchange reaction, was prepared. The various properties of the catalyst, such as the thermal stability, pore structure and the platinum dispersion, were investigated. A hydrophobic Pt/SDBC catalyst which has been developed for the LPCE column of the WTRF (Wolsong Tritium Removal Facility) was tested in a trickle bed reactor. An experimental apparatus was built for the test of the catalyst at various temperatures and gas velocities.

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정지홈과 회전홈을 갖는 저널베어링의 안정성 평가 (Stability analysis of the rotating and stationary grooved journal bearings)

  • 이민호;이지훈;장건희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2013년도 춘계학술대회 논문집
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    • pp.141-146
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    • 2013
  • This research investigates the stability analysis for the rotating and the stationary grooved journal bearing. The dynamic coefficients of the journal bearing are calculated by using FEM and the perturbation method. When journal bearing is in whirling motion, the dynamic coefficients have time-varying components as a sine wave due to the reaction force of oil film toward the center of journal even in the steady state. The solutions for the equations of motion can be assumed as the Fourier series expansion. The equations of motion can be rewritten as the linear algebraic equations with respect to the Fourier coefficients. Then, stability of the grooved journal bearing can be calculated by Hill's infinite determinant. The periodic function of dynamic coefficients is derived using Fourier Fast Transform(FFT).The stability of journal bearing is determined as rotating speed increases and the stability of rotating grooved journal bearing is compared and discussed with the stability of stationary grooved journal bearing.

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STABILITY AND BIFURCATION IN A DIFFUSIVE PREY-PREDATOR SYSTEM : NON-LINEAR BIFURCATION ANALYSIS

  • Bhattacharya, Rakhi;Bandyopadhyay, Malay;Banerjee, Sandip
    • Journal of applied mathematics & informatics
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    • 제10권1_2호
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    • pp.17-26
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    • 2002
  • A stability analysis of a non-linear prey-predator system under the influence of one dimensional diffusion has been investigated to determine the nature of the bifurcation point of the system. The non-linear bifurcation analysis determining the steady state solution beyond the critical point enables us to determine characteristic features of the spatial inhomogeneous pattern arising out of the bifurcation of the state of the system.

Reaction of Lithium 2-Pyridyloxyalkylcuprates Having Improved Thermal Stability with Acid Chlorides and $\alpha,\beta$-Unsaturated Ketones

  • Lee, Phil-Ho;Shim, Sang-Chul;Kim, Sung-Gak
    • Bulletin of the Korean Chemical Society
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    • 제7권6호
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    • pp.425-428
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    • 1986
  • A new heterocuprate containing 2-pyridyloxy ligand, lithium 2-pyridyloxy-n-butylcuprate, has shown improved thermal stability and it reacts with acid chlorides to afford the corresponding ketones in high yields. Similarly, it can be effectively utilized in conjugate addition reactions of $\alpha,\beta$-unsaturated ketones. Of synthetic significance is that the complete utilization of n-butyl group in lithium 2-pyridyloxy-n-butylcuprate has been observed.

Stereoselective Total Synthesis of (-)-Cytoxazone

  • Kim, Ji-Duck;Hoon, Jung-Young
    • 대한약학회:학술대회논문집
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    • 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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    • pp.179.2-179.2
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    • 2003
  • We have developed the novel one-pot synthetic method for regioselective and stereoselective N-protected amines through the reaction of various ethers with chlorosulfonyl isocyanate (CSI). Also, we found a novel technique to compare directly the stability of carbocations in the solution phase and established the stability order of the various carbocations. And we reported the cleavage of benzyl and p-methoxybenzyl protecting groups of alcohols and phenols in the presence of other functional groups using CSI. (omitted)

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