• Journal of the Korean Chemical Society
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• v.51 no.3
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• pp.227-231
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• 2007

We improve Wilehemski-Fixmann theory for intrachain reaction dynamics of a polymer chain by taking into account excluded volume effects between reactive groups in the polymerchain. An approximate analytic expression for the intra-chain reaction dynamics is obtained for Gaussian chain model and compared to Brownian dynamics simulation results. The results of the present theory are in a better agreement to Brownian dynamics simulation results than those calculated by previously reported theories.

• 건축구조
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• v.13 no.1
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• pp.46-58
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• 2006

구조동력학 이론에 기초하여 내진설계 기술이 개발되었다. 그러므로 건축물의 내진설계를 근본적으로 이해하기 위해서는 구조동력학의 여러 가지 이론들을 먼저 알고 이들이 내진설계에 어떻게 적용이 되는지를 알아야 한다. 이 글은 구조기술자 여러분이 건축물의 내진설계를 이해하는데 도움이 될 수 있도록 하기 위하여 다음과 같이 3부로연재될예정이다. 제1부: 응답스펙트럼과구조물의동적해석 제2부: 등가정적해석법과반응수정계수의배경 제3부: 능력스펙트럼법에의한비탄성해석 제1부에서는 단자유도 구조물의 지진해석을 통하여 응답스펙트럼을 작성하는 원리와 이를 이용하여 간편하게 지진해석을 수행하는 방법을 소개하고 응답스펙트럼에 근거하여 설계응답스펙트럼을 작성하는 방법과 다자유도 구조물의 지진응답을 알아내기 위한 응답 스펙트럼 해석법에 관하여 소개한다. 제2부에서는 구조동력학 이론에 근거하여 등가정적해석법이 유도된 근거와 반응수정계수를 사용하게 되는 배경을 소개하여 구조기술자들이내진설계에좀더확실한이해를할수있도록할것이다. 마지막으로 제3부에서는 비탄성해석을 좀 더 쉽게 하기 위하여 사용되는 능력스펙트럼법의 배경과 이를 이용하여 건축물의 성능점을 찾는 방법과 구조물의 비탄성 지진응답을 평가하는 방법에 대하여 소개함으로써 성능에 기초한 내진설계를 위한 기초 이론을 확실히 이해할수있도록할것이다. 구조동력학에 관한 내용을 여기에 상세히 소개하자면 엄청난 분량이 될 것이므로 여기서는 이 글을 읽는 구조기술자들이 구조동력학에 관한 기초적인 내용을 이해하고 있는 것으로 가정하기로 한다. 그러므로 구조동력학에 대한 기초적 이론을 확실히 이해하고 있지 못한분들은이글을읽기전에먼저구조동력학에관한알기쉬운서적을 먼저 읽도록 추천한다.

• Journal of the Korean Chemical Society
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• v.50 no.4
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• pp.277-280
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• 2006

We report an exact relation between the survival probability, the revisit time distribution, and the reaction-free propagator of the continuous time random walker. The relation holds even for such a general case where the random walker has a distinct jump dynamics at each lattice site, which may be dependent also on the direction of the jump. The application range of the obtained relation is not limited to the nearest neighbor hopping in the bulk lattice either. The result is applicable to a higher dimensional system with the spherical symmetry as well as it is to the one-dimensional system.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.18 no.1
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• pp.36-44
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• 1989

• Clean Technology
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• v.17 no.2
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• pp.97-102
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• 2011

The adsorption characteristics of amatanth dye by granular activated carbon were experimently investigated in the batch adsorption. Kinetic studies of adsorption of amaranth dye were carried out at 298, 308 and 318 K, using aqueous solutions with 100, 200 and 300 mg/L initial concentration of amatanth. It was established that the adsorption equilibrium of amaranth dye on granular activated carbon was successfully fitted by Langmuir isotherm equation at 298 K. The pseudo first order and pseudo second order models were used to evaluate the kinetic data and the pseudo second order kinetic model was the best with good correlation. Values of the rate constant ($k_2$) have been calculated as 0.1076, 0.0531, and 0.0309 g/mg h at 100, 200 and 300 mg/L initial concentration of amatanth, respectively. Thermodynamic parameter such as activation energy, standard enthalpy, standard entropy and standard free energy were evaluated. The estimated values for standard free energy were -5.08 - -8.10 kJ/mol over activated carbon at 200 mg/L, indicated toward a spontaneous process. The positive value for enthalpy, 38.89 kJ/mol indicates that adsorption interaction of amatanth dye on activated carbon is an endothermic process.

• Clean Technology
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• v.20 no.3
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• pp.290-297
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• 2014

Batch adsorption studies were carried out for equilibrium, kinetics and thermodynamic parameters for adsorption of coomassi brilliant blue G (CBBG) using activated carbon with varying the operating variables like initial concentration, contact time and temperature. Equilibrium adsorption data were fitted into Langmuir, Freundlich and Dubinin-Radushkevich isotherms. From estimated separation factor of Langmuir and Freundlich, this process could be employed as effective treatment for removal of CBBG. Also from Dubinin-Radushkevich isotherm model, adsorption energy (E) indicated adsorption process is physical adsorption. From kinetic experiments, the adsorption reaction was found to confirm to the pseudo second order model with good correlation. Intraparticle diffusion was rate controlling step. Thermodynamic parameters like change of free energy, enthalpy, and entropy were also calculated to predict the nature of adsorption. The change of enthalpy (406.12 kJ/mol) indicated endothermic nature of the adsorption process. The change of entropy (1.66 kJ/mol K) showed increasing disorder in process. The change of free energy found that the spontaneity of process increased with increasing adsorption temperature.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.234-235
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• 2002

최근 상호 결합된 chaotic 진동자들 간의 동기화의 문제는 그 시스템이 가지는 여러 가지 응용성 때문에 여러 과학 분야와 기술 분야 예를 들면 동력학, 레이져 동력학, 전자회로, 화학반응, 생물학적인 시스템 등에서 폭넓게 연구되어지고 있다. 더욱이 작은 파라미터의 차이를 제외하고 거의 유사한 chaotic 진동자들간의 상호작용에서 찾아 볼 수 있는 위상 동기화 현상은 뇌세포 조직과 같은 생물학적인 시스템들 사이에 흔히 찾아 볼 수 있는 기본적인 현상이다. (중략)

• Polymer(Korea)
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• v.24 no.1
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• pp.65-71
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• 2000

The latent properties and cure kinetics of an acid anhydride-cured epoxy resin have been investigated by a near-infrared (NIR) reflection spectroscopy. The assignments of the latent properties and cure behaviors were performed by the measurements of the NIR reflectance for epoxide and hydroxyl groups at different temperatures. A comprehensive analysis of the origin, location, and shifts during reaction of all major NIR absorption peaks in the spectral range from 4000 to 7100 $cm^{-1}$ / was provided. The extent of reaction was determined from NIR absorption band at the 4530 $cm^{-1}$ / depending on epoxide concentration and cure temperature.

• Microbiology and Biotechnology Letters
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• v.15 no.2
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• pp.98-103
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• 1987

Two phase reaction system was used to hydrolyze the olive oil for fat splitting. Kinetics of lipases in two phase system were investigated by determining the hydrolysis rate of triglycerides at various olive oil concentrations in isooctane using the microbial lipases from Candida rugosa and Rhizopus arrhizus. The rate equation in lipid hydrolysis for various olive oil concentrations in two phase system was deviated from the Michaelis-Menten kinetics. The results suggested that the olive oil concentration in isooctane affects the interfacial area. The dependency of the interfacial area on olive oil concentration is greater at the lower olive oil concentration than at the higher substrate concentration. We modified the rate equation by considering the interfacial area between two phases depending on the olive oil concentration in solvent phase.

• Journal of Ocean Engineering and Technology
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• v.1 no.2
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• pp.39-51
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• 1987

석유시추 보호관의 비선형 운동을 시뮬레이트하는 유효한 해법이 non-uniform grid 유한차분법과 implicit time 적분법에 근거하여 제시되었다. 극한 상태에 있는 지지 플랫폼의 상승 가속도에 의해 생기는 보호관의 동적 좌굴형 반응에 관하여 상세히 연구되었고, 이 반응에 미치는 중요 변수가 규명되었다. 운동의 현저한 감소와 이에 따른 응력들이 컴플라이언트 행오프(hang-off)를 적용시킴으로써 얻어졌다.