• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.448-460
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• 2018

Copper nanoparticle-doped and graphitic carbon nanofibers-covered porous carbon beads were used as an efficient catalyst for treating synthetic phenolic water by catalytic wet air oxidation (CWAO) in a packed bed reactor over 10-30 bar and $180-230^{\circ}C$, with air and water flowing co-currently. A mathematical model based on reaction kinetics assuming degradation in both heterogeneous and homogeneous phases was developed to predict reduction in chemical oxygen demand (COD) under a continuous operation with recycle. The catalyst and process also showed complete COD reduction (>99%) without leaching of Cu against a high COD (~120,000 mg/L) containing industrial wastewater.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.223-228
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• 1997

The gas dynamics in a stagnation point upflow OMVPE reactor were studied by Raman spectroscopy. The gas temperature was measured as a function of inlet gas velocity and aspect ratio for both H$_2$ and N$_2$ carrier gases. The centerline temperature gradient was latger at higher inlet velocities and with the use of N$_2$, and only weakly dependent on the aspect ratio. a tracer molecule, CH$_4$, was used to investigate the steady state behavior of reactants in the reactor, and the use of a sweeping flow was found to be a suitable method for preventing wall deposition. The transient switching response of the gas manifold was also investigated. Under certain conditions (low velocities, unmatched flows) recirculation flows were apparent. Numerical calculations of the reactor gas dynamics gave reasonable agreement with experimental results when detailed thermal boundary conditions were included.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.63-68
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• 1999

In this paper, characteristics of ozone generation by using coil and SPCP + DC corona reactor was studied. The ceramic-based surface discharge electrode, which was first invented as a high-efficiency ozonizer, has been used as an experimental plasma chemical reactor.(Surface Induced Plasma Chemical Processing, SPCP.) The electrode, however, has a structural disadvantage that a highly energetic plasma region is localized near the electrode surface, which may make it impossible for higher efficiency to realize. In an attempt to overcome this advantage, we have developed a hybrid reactor which employs a corona discharge unit together with the surface discharge unit. Experimental results suggest that the efficiency of the ozone production rate is improved when positive corona discharge is added.

• Journal of the Korean Mathematical Society
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• v.49 no.3
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• pp.641-658
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• 2012

The goal of this paper is to develop a nonlinear observer-based control strategy for a multi-variables continuous stirred tank reactor (CSTR). A new robust nonlinear observer is constructed to estimate the whole process state variables. The observer is coupled with a nonlinear controller, designed based on the input-output linearization for controlling the concentration and reactor temperature. The closed loop system is shown to be globally asymptotically stable based on Lyapunov arguments. Finally, computer simulations are developed for showing the performance of the proposed controller.

• 연구논문집
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• s.33
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• pp.123-135
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• 2003

Using the residence time calculated by computer simulation for temperature and gas velocity distribution in CVC reactor, the kinetics on the formation of $TiO_2$ nano powder was analyzed for coagulation process, After abrupt increase of particle size at initial growth stage (< 0.2 $\mus$ ), the particle grew in proportion of cubic root to time. The numerically calculated particle sizes well agreed with the experimental results. However, the coarse rutile $TiO_2$ powders having the particle size of over 40 nm were formed on the surface of quratz rod in the reactor. it is thought that the fine anatase particles condensed on quratz rod were sintered in a heated CVC reactor to grow and transform to coarse rutile phase, and the critical size for phase transformation anstase-to-rutile was around 25 nm tn this study.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.191-194
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• 2004

A novel type of intelligent microcapsule reactor system was prepared. The reactor can recognize pH change in the medea and control reaction rate by itself. For the reactor system, acrylic acid (AA), N-isopropylacrylamide (NIPAM), and glucose oxidase (GOD) were selected as a pH-responsive device, a gating device according and a reaction device, respectively. Poly(NIPAM-co-AA) (P-NIPAM-co-AA) are known to change its hydrophilicity-hydrophobicity due to pH change. They were integrated in a core-shell microcapsule space. GOD was loaded inside the core space and the pores in the outside shell layer were filled with P-NIPAM-co-AA linear grafted chains as pH-responsive gates by plasma graft filling polymerization method. When P-NIPAM-co-AA gates are hydrophilic at high pH value, this microcapsule permits glucose penetration into the core space and GOD reaction proceeds. However, when P-NIPAM-co-AA gates are hydrophobic at low pH value, this microcapsule forbids glucose penetration and GOD reaction will not occur. The accuracy of this concept was examined.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.229-233
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• 2022

In this study, a gas-liquid hybrid atmospheric pressure plasma reactor of the dielectric barrier discharge method was fabricated and characterized. The solubility of copper oxide in the organic acid solution was increased when argon having a larger atomic weight than helium was used during plasma discharge. There was no significant effect of mixing organic acid solutions under plasma discharge treatment on the variation of copper oxide's solubility. As the applied voltage for plasma discharge and the concentration of the organic acid solution increased, the dissolution and removal power of the copper oxide layer increased. Solubility of copper oxide was more affected by the concentration in organic acid solution rather than the variation of plasma applied voltage. The usefulness of hybrid plasma reactor for the surface cleaning process was confirmed.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.1
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• pp.24-34
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• 2003

For gaseous fuel combustion with inherent $CO_2$ capture and low NOx emission, chemical-looping combustion may yield great advantages for the savings of energy to $CO_2$ separation and suppressing the effect on environment, In chemical-looping combustor, fuel is oxidized by metal oxide medium in a reduction reactor. Reduced particles are transported to oxidation reactor and oxidized by air and recycled to reduction reactor. The fuel and the air are never mixed, and the gases from reduction reactor, $CO_2$ and $H_2O$, leave the system as separate stream. The $H_2O$ can be easily separated by condensation and pure $CO_2$ is obtained without any loss of energy for separation. In this study, five oxygen carrier particles such as NiO/bentonite, NiO/YSZ, $(NiO+Fe_2O_3)VYSZ$, $NiO/NiAl_2O_4$, and $Co_{\chi}O_y/CoAl_2O_4$ were examined &om the viewpoints of reaction kinetics, oxygen transfer capacity, and carbon deposition characteristics. Among five oxygen particles, NiO/YSZ particle is superior in reaction rate, oxygen carrier capacity, and carbon deposition to other particles. However, at high temperature ($>900^{\circ}C$), NiO/bentonite particle also shows enough reactivity and oxygen carrier capacity to be applied in a practical system.

• Applied Chemistry for Engineering
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• v.16 no.3
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• pp.434-439
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• 2005

The reaction of hydration proceeded at the same time the vapor was introduced into the reactor that was filled with calcined dolomite. It has shown that the temperature has begun to fall from the bottom of reactor after increase of temperature by the heat of hydration reaction. The reaction initiated at the pipe wall and the heat was transfer to the center of block between the fins. The results show that the use of copper fin in the reactor reducted the hydration reaction time by half when compared to the case without using the fins.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1533-1537
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• 2007

In this study, in order to develop a continuous production process of lactosucrose in a packed-bed reactor, Sterigmatomyces elviae ATCC 18894 was selected and mutated. The mutant strain of S. elviae showed 54.3% higher lactosucrose production than the wild type. Reaction conditions such as temperature, pH, substrate concentration and flow rate were also optimized. Under optimized reaction conditions ($50^{\circ}C$, pH 6.0, 25% sucrose and 25% lactose as substrate, flow rate 1.2 ml/min), the maximum concentration of lactosucrose (192 g/l) was obtained. In a packed-bed reactor, continuous production of lactosucrose was performed using S. elviae mutant immobilized in calcium alginate, and about 180 g/l of lactosucrose production was achieved for 48 days.