• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.981-983
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• 2010

The condensation of several aromatic/heteroaromatic aldehydes with 2-aminothiophenol catalyzed by silica sulfuric acid under microwave irradiation afforded 2-arylbenzothiazoles in high yields and short reaction times under solvent-free conditions. The major advantages of the present method are good yields, ecofriendly, reusable catalyst, mild and solvent-free reaction conditions.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.128-131
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• 2003

The effect of microwave irradiation on waste activated sludge was investigated in order to improve solubilization. a different levels of microwave irradiation time were varied within a range from 1 min to 15 min. When WAS was pretreated at 1, 3, 5, 7, and 15 min, the SCOD concentration increased according to microwave irradiation time. A simple batch procedure was used to measure the VFA potential, i.e. the amount of VFA that can be formed through digestion of organic constituent in sludge. At equilibrium point, TVFA in the case of 1, 3, 5, 7 and 15 min microwaved sludges was 8%, 122%, 243%, 279% and 232% higher than that in the case of raw sludge, respectively.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.65-65
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• 2000

Microwave response of intrinsic Josephson junctions in mesa structure formed on HgI2-intercalated Bi2Sr2CaCu2O8+x single crystals was studied in a wide range of microwave frequency. With irradiation of 73${\sim}$76 GHz microwave, the supercurrent branch becomes resistive above a certain onset microwave power. At low current bias, the current-voltage characteristics show linear behavior, while at high current bias, the resistive branch splits into multiple sub-branches. The voltage spacing between neighboring sub-branches increase with the microwave power and the total number of sub-branches is almost identical to the number of intrinsic Josephson junctions in the mesa. All the experimental results suggest that each sub-branch represents a specific mode of collective motion of Josephson vortices generated by the microwave irradiation. With irradiation of microwave of microwave of frequency lower than 20 GHz, on the other hand, no branch splitting was observed and the current-voltage characteristics exhibited complex behavior at hlgh blas currents. This result can be explained in terms of incoherent motion of Josephson vortices generated by non-uniform microwave irradiation.

• Korean Journal of Food Science and Technology
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• v.49 no.6
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• pp.693-698
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• 2017

Turmeric is a yellow food-coloring spice containing curcuminoids, curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin (BMC), which have several physiological effects. In the present study, the effect of microwave irradiation on the chemical properties, antioxidant activity, and cytotoxicity of turmeric were investigated. Degradation of turmeric pigments was accelerated upon increase in irradiation time or intensity at 405 nm. Residual levels of curcumin, DMC, and BMC after 5 minutes of irradiation at 700 W were 11.3, 34.4, and 71.2%, respectively. Scavenging activities of turmeric pigment against 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-azobis (2-amidinopropane) dihydrochloride (AAPH) peroxyl radical and nitrite were enhanced significantly after microwave radiation. However, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity remained unaffected. Cytotoxic activity of turmeric was significantly reduced, and hydrogen peroxide generated from turmeric increased after microwave irradiation. The results obtained indicate that microwave irradiation affects chemical stability and bioactivity of turmeric pigment. Hence, these effects should be considered when processing foods containing turmeric pigments.

• Journal of the Korean Chemical Society
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• v.54 no.4
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• pp.419-428
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• 2010

Here we describe a fast and rapid technique for preparation of amino acid hydrazide as well as peptide hydrazide derivatives using diisopropylcarbodiimide (DIC)/1-hydroxybenzotriazoles (HOXt) (X = A or B) under microwave irradiation employing a multimode reactor (Synthos 3000 Aton Paar, GmbH, 1400 W maximum magnetron). A comparison between conventional and microwave irradiation was described. The microwave methodology is rapid, convenient, proceeds under mild conditions. Diisopropylcarbodiimide (DIC)/7-aza-1-hydroxybenzotriazole (HOAt) always gave much better yield (95 - 98%) and purity than diisopropylcarbodiimide (DIC)/1-hydroxybenzotriazole (HOBt).

• Journal of Environmental Science International
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• v.22 no.1
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• pp.83-89
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• 2013

Silicon carbide with aluminium oxide was used to remove the sulphur hexafluoride ($SF_6$) gas using microwave irradiation. The destruction and removal efficiencies (DREs) of $SF_6$ were studies as a function of various decomposition temperatures and microwave powers. The decomposition of $SF_6$ gas was analyzed using GC-TCD. XRD (X-ray powder diffraction) and XRF (X-ray Fluorescence Spectrometer) were used to characterize the properties of aluminum oxide. DREs of $SF_6$ were increased as the microwave powers were increased. Additive aluminium oxide on SiC increased the removal efficiencies and decreased the decomposition temperature. The XRD results show that the ${\gamma}-Al_2O_3$ was transformed to ${\alpha}-Al_2O_3$ during $SF_6$ decomposition by microwave irradiation. It was found that the best material to control $SF_6$ was SiC with $Al_2O_3$ 30 wt% in consideration of microwave energy consumption and $SF_6$ decomposition rate.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.2
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• pp.133-142
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• 1998

Gas adsorption on adsorbents depends on temperatures and pressures. When these parameters are fixed, the adsorption capability and selectivity can not be changed. If the gas adsorption is controlled by another factor like electromagnetic field, the adsorption and desorption can be managed by much intentional way. The microwave has characteristics to excite particular components such as water without destroying it. In this study, microwave was irradiated to the adsorbent of an NaY zeolite which is almost transparent to microwave. As vapor of 1, 1, 2- trichloro-1, 2, 2-trifluoroethane (CFC-113) and water flowed simultaneously on the zeolite packed in a column at room temperature, only water was adsorbed. The . adsorbed water was removed from the zeolite and then replaced by CFC-113, since the microwave was irradiated. Greater the power of microwave was, more CFC-113 was adsorbed. The water adsorption took place again after a latent period by stopping the microwave irradiation.

• The Journal of Korean Academy of Prosthodontics
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• v.28 no.2
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• pp.109-124
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• 1990

The purpose of this study was to investigate the physical propertise and determine whether three were any differences in the amount of porosity of the denture base resins cured by microwave irradiation and conventional water bath heating. The resins used in this study were K-33 resin and Acron MC resin. The properties selected were transverse strength, Knoop hardness, and density. A ten-power eyepiece and scanning electron microscope(Magnification of ${\times}$ 30and ${\times}$150)were used to examine the specimens for porosity. Through analyses of the data from this study, the following conclusions were obtained. 1. Microwave energy can be effectively use dtopolymerize poly(methylmethacrylate) denture base resins. 2. In the transverse strength, K-33 resin cured by microwave irradiation was the first highest, water bath cured K-33 resin the second, microwave cured Acron MC resin the third, water bath cured Acron MC resin the fourth. 3. In the Knoop hardness, K-33 resin cured by microwave irradiation was the first hardest, water bath cured K-33 resin the second, water bath cured Acron MC resin the third, microwave cured Acron MC resin the the fourth. 4. No significant difference was found between the density of resin denture bases polymerized by either method. 5. K-33 resin showed the most porosity for the microwave curing. But there was no significant difference in the Acron MC resin and other curing method.

• Macromolecular Research
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• v.17 no.11
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• pp.901-906
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• 2009

Several aromatic optically active polyamides (PA)s were synthesized from 5-(2-phthalimidiylpropanoylamino)isophthalic acid with various aromatic diamines via direct polycondensation with triphenyl phosphite and pyridine in the presence of calcium chloride and N-methyl-2-pyrrolidone under microwave irradiation and conventional heating conditions. Under the optimized conditions, the reaction mixture was irradiated for 2 min. with a 100% irradiation power (900 W). The resulting polymers were obtained in high yield and moderate inherent viscosity ranging from 0.35 to 0.60 dL/g. All synthesized polymers showed excellent solubility in amide-type solvents. Thermogravimetric analysis revealed a 10% weight loss temperature and char yield at $600^{\circ}C$ in a nitrogen atmosphere of > $350^{\circ}C$ and > 58%, respectively, which suggests that the resulting PAs have good thermal stability.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1155-1158
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• 2010

Microwave-assisted Michael reaction between EMME and various amines such as diphenylamine, 4-methyl-N-phenylbenzenamine, N-phenylnaphthalen-1-amine, dihexylamine, diisopropylamine, and 4-nitrobenzenamine were described. Solvent-free conditions on alumina as solid support in the presence of $K_2CO_3$ catalysts gave moderate to good yields (55 - 93%) of diethylmalonate analogues having enamine moieties under focused microwave irradiation.