• 제목/요약/키워드: Global reaction

검색결과 349건 처리시간 0.027초

GLOBAL COUPLING EFFECTS ON A FREE BOUNDARY PROBLEM FOR THREE-COMPONENT REACTION-DIFFUSION SYSTEM

  • Ham, Yoon-Mee
    • 대한수학회지
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    • 제43권3호
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    • pp.659-676
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    • 2006
  • In this paper, we consider three-component reaction-diffusion system. With an integral condition and a global coupling, this system gives us an interesting free boundary problem. We shall examine the occurrence of a Hopf bifurcation and the stability of solutions as the global coupling constant varies. The main result is that a Hopf bifurcation occurs for global coupling and this motion is transferred to the stable motion for strong global coupling.

준충류 근사를 이용한 수소-공기 비예혼합화염의 질소산화물 생성예측 (Numerical Prediction of NOx in the Nonpremixed Hydrogen-Air Flame using the Quasi-Laminar Reaction Modelling)

  • 김성룡;정인석;윤영빈
    • 한국연소학회지
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    • 제4권1호
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    • pp.131-139
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    • 1999
  • A Numerical Analysis of NOx production in Hydrogen-Air flame is performed using the quasi-laminar reaction modelling. As results, in low global strain rate region, $U_F/D_F\;{\leq}\;50,000$, the quasi-laminar reaction modelling reproduces the experimentally observed EINOx half power scaling that the ratio of EINOx and flame residence time, $L_f^3(D_F^2U_F)$, is proportional to the square root of global strain rate. Thus, it suggests that turbulence-chemistry interaction has a minor impact on the trend of NOx production in low global strain rate region. However, the quasi-laminar reaction modelling predicts the higher temperature and NOx than experimentally observed. This overprediction may be due to the lack of radiation and quasi-laminar reaction modelling.

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A STUDY ON INVARIANT REGIONS, EXISTENCE AND UNIQUENESS OF THE GLOBAL SOLUTION FOR TRIDIAGONAL REACTION-DIFFUSION SYSTEMS

  • IQBAL M. BATIHA;NABILA BARROUK;ADEL OUANNAS;ABDULKARIM FARAH
    • Journal of applied mathematics & informatics
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    • 제41권4호
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    • pp.893-906
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    • 2023
  • In this article, we are devoted to study the problem of the existence, uniqueness and positivity of the global solutions of the 3 × 3 reaction-diffusion systems with the total mass of the components with time. We also suppose that the nonlinear reaction term has a critical growth with respect to the gradient. The technique that we used to prove the global existence is the method of the compact semigroup.

Secondary nanoparticle formation by a reaction of ozone and volatile organic compounds emitted from a commercial home cleaner liquid

  • Vu, Thai Phuong;Kim, Sun-Hwa;Lee, Seung-Bok;Bae, Gwi-Nam
    • 한국입자에어로졸학회지
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    • 제7권1호
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    • pp.1-8
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    • 2011
  • In this study, the formation of nanoparticles by a reaction of ozone with the volatile organic compounds(VOCs) emitted from a commercial home cleaner liquid was investigated using a $1-m^3$ reaction chamber($1{\times}1{\times}1m$). The home cleaner liquid was found to contain many VOCs, particularly terpenes. Some of these VOCs are known to readily react with ozone, forming indoor secondary pollutants. The correlation of particle concentration and reacted ozone concentration was examined with injections of three different ozone concentrations; 50, 100 and 200 ppb. The secondary nanoparticles were formed faster, with their numbers and mass concentrations becoming higher on increasing the concentration of ozone injected.

황 회수 공정 설계에서 부 반응의 영향 (The Impact of Side Reactions in Sulfur Recovery Unit Design)

  • 김성호;정원석;이희문;장근수
    • 플랜트 저널
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    • 제13권3호
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    • pp.36-46
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    • 2017
  • 황회수 공정의 연소반응기 안에서는 평형반응 및 kinetic 반응이 동시에 일어난다. 주요 kinetic 반응에 참여하는 성분들은 수소($H_2$), 일산화탄소(CO), 카보닐황화물(COS) 그리고 이황화탄소($CS_2$) 이다. 본 연구에서는 평형반응, 상관관계식(empirical correlations) 그리고 황 회수 공정의 라이센서 자료의 비교를 통해 반응기에서 kinetic components (COS와 $CS_2$)의 생성 양을 분석한다. 또한 kinetic components ($H_2$ 와 CO)의 생성 양의 분석을 통해 반응기에서의 생성 양과 온도와의 상관관계를 분석한다. 부 반응이 전체 연소에 필요로 하는 산소의 양에 어떤 영향을 미치는지도 같이 분석을 한다. 황회수 공정의 반응기내의 부 반응에 대한 충분한 이해는 전체 황회수 공정 설계를 할 때 최적의 장치 설계를 가능하게 하고 나아가 황회수 효율을 극대화 하는데 도움이 된다.

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Sliding Mode Control of Spacecraft with Actuator Dynamics

  • Cheon, Yee-Jin
    • Transactions on Control, Automation and Systems Engineering
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    • 제4권2호
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    • pp.169-175
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    • 2002
  • A sliding mode control of spacecraft attitude tracking with actuator, especially reaction wheel, is presented. The sliding mode controller is derived based on quaternion parameterization for the kinematic equations of motion. The reaction wheel dynamic equations represented by wheel input voltage are presented. The input voltage to wheel is calculated from the sliding mode controller and reaction wheel dynamics. The global asymptotic stability is shown using a Lyapunov analysis. In addition the robustness analysis is performed for nonlinear system with parameter variations and disturbances. It is shown that the controller ensures control objectives for the spacecraft with reaction wheels.