• Particle and aerosol research
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• v.11 no.3
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• pp.77-85
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• 2015

A Belousov-Zhabotinsky reaction in a liquid-liquid system under microwave radiation was observed under non-stirring conditions. To control this non-equilibrium reaction, nano-particle, which is active under microwave irradiation, was added to the solution. Color changes of the solution during the oscillatory reaction were found to be influenced by the irradiation power although the droplet temperature was equal to the temperature of surrounding oil. During the irradiation, the period of oscillation became shorter because the reaction rate was faster. It could also be observed that there is possibility to eliminate oscillatory behaviors of the reaction using higher power of microwave. The possibility of controlling non-linear reaction using microwave was shown since microwave can easily travel through oil phase and reach water phase.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.44-47
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• 1998

A reduction/oxidation reaction between A1 metal powder and SiO2 powder was performed by Self-propagating High-temperature Synthesis (SHS) reaction induced by microwave energy to produce a composite of Al2O3 and Si powders by using a 2.45 GHz kitchen model microwave oven. A Microwave Hybrid Heating(MHH) method was applied by using SiC powders as a suscepting material to raise the temperature of the disk samples and the heat increase rate of over 100℃/min were obtained before the reaction. The reaction started around 850℃ and the heat increase rate jumped to over 200℃/min after the reaction took place.

• Analytical Science and Technology
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• v.30 no.3
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• pp.138-145
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• 2017

Microwave-assisted organic synthesis has gained a remarkable interest over the past years because of its advantages - (i) rapid energy transfer and superheating, (ii) higher yield and rapid reaction, (iii) cleaner reactions. Ionic liquids are well known for their unique properties such as negligible vapor pressure and high thermal stability. With these properties, ionic liquids have gained increasing attention as green, multi-use reaction media. Recently, ionic liquids have been applied as reaction media for biocatalysis. Lipase-catalyzed reactions in ionic liquids provide high activity and yield compared to conventional organic solvents or solvent free system. Since polar molecules are generally good absorbent to microwave radiation, ionic liquids were investigated as reaction media to improve activity and productivity. In this study, therefore, the effect of microwave irradiation in ionic liquids was investigated on lipase catalyzed reactions such as benzyl acetate synthesis and caffeic acid phenethyl ester synthesis. Comparing to conventional heating, microwave heating showed almost the same final conversion but increased initial reaction rate (3.03 mM/min) compared to 2.11 mM/min in conventional heating at $50^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2029-2033
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• 2007

Hydrotalcite, layered double hydroxides (LDH), with hexagonal morphology has been rapidly synthesized by microwave reaction within 1 hour by urea hydrolysis from homogeneous solution. Different synthesis parameters, Mg/Al molar ratio, microwave reaction temperature and microwave power were systematically investigated. Pure hydrotalcite phase was obtained for Mg/Al ratios of 2:1 and 3:1, and higher reaction temperature gave higher crystallinity. The hydrotalcite synthesized at 600W power shows the highest crystallinity and more homogeneous crystal size distribution. The hydrotalcite samples were characterized by powder X-ray diffraction (XRD), simultaneous thermogravimetric/differential thermal analysis (TG/DTA), Fourier Transform Infrared (FT-IR) and Scanning electron micrograph (SEM).

• Bulletin of the Korean Chemical Society
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• v.24 no.2
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• pp.253-255
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• 2003

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1957-1964
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• 2011

Various reaction conditions uding temperature, time and type and concentration of templates have been changed in order to facilely synthesize, especially with microwave (MW) heating, SAPO-34 molecular sieves. SAPO-34 molecular sieve can be synthesized rapidly with microwave irradiation from a gel containing tetraethylammonium hydroxide (TEAOH) as a template. However, other several templating molecules lead to SAPO-5 molecular sieve under microwave irradiation even though SAPO-34 is obtained by conventional electric synthesis from the same reactant gels. Moreover, SAPO-34 can be obtained more easily by increasing the TEAOH or silica concentration or by increasing the reaction temperature. SAPO-34 can be obtained within 5 min in a selected condition (high temperature of 210 $^{\circ}C$) with microwave heating, which may lead to a continuous production of the important material. SAPO-34 synthesized by microwave irradiation is homogeneous and small in size and shows acidity and a stable performance in the dehydration of methanol and 2-butanol to olefins, suggesting potential applications in acid catalysis.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.773-778
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• 2018

In-situ transesterification of microalgae lipids using microwave irradiation has potential to simplify and accelerate biodiesel production, as it minimizes production cost and reaction time by direct transesterification of microalgae into biodiesel with microwave as a heating source. This study was conducted to research the effect of microwave irradiation with in-situ transesterification of microalgae under base catalyst condition. The process variables (reaction time, solvent ratio, microwave power) were studied using 2% of catalyst concentration. The maximum yield of FAME was obtained at about 32.18% at the reaction time of 30 min with biomass-methanol ratio 1:12 (w/v) and microwave power of 450 W. The GC MS analysis obtained that the main component of FAME from microalgal oils (or lipids) was palmitic acid, stearic acid and oleic acid. The results show that microwaves can be used as a heating source to synthesize biodiesel from microalgae in terms of major components resulting.

• Journal of the Korean Ceramic Society
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• v.48 no.5
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• pp.354-359
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• 2011

Silicon nitride ceramics were prepared by microwave gas phase reaction sintering. By this method higher density specimens were obtained for short time and at low temperature, compared than ones by conventional pressureless sintering, even though sintering behaviors showed same trend, the relative density of sintered body inverse-exponentially increases with sintering temperature and/or holding time. And grain size of ${\beta}$-phase of the microwave sintered body is bigger than one of the conventional pressureless sintered one. Also they showed good bending strengths and thermal shock resistances.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.961-963
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• 2011

Spin-coated waterborne polyurethane to protect glass surface from environmental attacks was cured by using microwave heating. The effect of microwave heating on the reaction kinetics, chemical durability, and transmittance of polyurethane was investigated. In comparison to the conventional heating the results show that the microwave heating substantially accelerates the curing process of waterborne polyurethane and the total time for the completion of the reaction is only 1/7 of that in the conventional process. The microwave cured sample showed an excellent caustic resistance compared to conventional cured one. It means that microwave heating produces dense structure during curing process. The dense structure does not affect to the transmittance in the visible region.

• Journal of Ginseng Research
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• v.17 no.1
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• pp.35-38
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• 1993

A new and rapid method for the hydrolysis of ginsenosides to panaxadiol or panaxatriol was developed. It is based on the microwave oven reaction, which is high temperature and high-pressure reaction. The optimal hydrolysis time using 5% $H_2SO_4$ solution was found at 10 min PTFE reaction vessel in microwave oven, which is more than 30 times faster than the conventional hydrolysis method.