• Journal of the Korean Ceramic Society
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• v.41 no.9
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• pp.684-689
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• 2004

Hexagonal sheet typed $\alpha$-Al$_2$O$_3$ nano particles were synthesized successfully at various conditions with the aluminum sulfate solution extracted from kaolin through the conventional and microwave assisted polyacrylamide (PAA) gel methods. Shorter gel time and higher yield were obtained in the microwave assisted PAA gel method, compared to conventional method. the size of nano particles was not changed by increasing the concentration of aluminum sulfate, but decreased with increasing the concentration of cross-linking agent in both the conventional and microwave samples. Above 0.01M concentration of cross-linking agent, the sizes of nano particles in the microwave samples were relatively larger than those in the conventional samples.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2382-2388
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• 2007

A series of dimethine cyanine dyes were synthesized in a fast, efficient and high yield by the condensation of quaternary salts with 1H-indole-3-carbaldehyde in the presence of piperidine under solvent-free microwave irradiation. The products were identified by 1H NMR, IR, UV-Vis spectra and elemental analysis. The absorption and fluorescence properties of these dyes were investigated both experimentally and theoretically. Calculations performed at a combination of time-dependent density functional theory (TD-DFT) and the polarizable continuum model (PCM) reproduced the π-π* type absorption bands of the dyes. Regression analysis was used for studying theoretical results of the absorption maxima in different solvents. Compared with experimental counterparts, estimated overall uncertainties in the absorption maxima were about ±2%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.4
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• pp.166-171
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• 2006

[ $Cu_2O$ ] and Cu have been synthesized from the layered organic-inorganic hybrid, $Cu_2(OH)_3(CH_3COO){\cdot}H_2O$, assisted by microwave irradiation. $Cu_2O$ is formed in aqueous glucose solution, while metallic Cu is formed in ethylene glycol by reduction of $Cu_2(OH)_3(CH_3COO){\cdot}H_2O$. The influence of microwave irradiation time and concentration of glucose on $Cu_2O$ particles formation and growth has been examined. The morphologies of $Cu_2O$ particles change from spheres with a few fm size to nanowires with diameter of 40 nm as increasing the microwave irradiation times.

• Advances in nano research
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• v.13 no.5
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• pp.437-451
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• 2022

Synthesis approaches usually affect the physical and chemical properties of ferrites. This helps ferrite materials to design them for desired applications. Some of these methods are mechanical milling, ultrasonic method, micro-emulsion, co-precipitation, thermal decomposition, hydrothermal, microwave-assisted, sol-gel, etc. These methods are extensively reviewed by taking example of ZnFe₂O₄. These methods also affect the microstructure and local structure of ferrite which ultimately affect the physical and chemical properties of ferrites. Various spectroscopic techniques such as Raman spectroscopy, Fourier Transform Infrared spectroscopy, Ultra Violet-Visible spectroscopy, Mossbauer spectroscopy, extended x-ray absorption fine structure, and electron paramagnetic resonance are found helpful to reveal this information. Hence, the basic principle and the usefulness of these techniques to find out appropriate information in ZnFe₂O₄ nanoparticles is elaborated in this review.

• Journal of the Korean Ceramic Society
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• v.27 no.4
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• pp.513-520
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• 1990

Diamond film was deposited on Si wafer substrate from a gas mixture of methane, hydrogen and oxygen by microwave plasma-assisted chemical vapor deposition. The effects of the pre-treatments of the substrate and of the oxygen addition on the diamond film synthesis are described. In order to obtain diamond film, the substrate was pre-treated with 3 kinds of methods. When the substrate was ultrasonically vibrated within the ethyl alcohol dispersed with 25${\mu}{\textrm}{m}$ diamond powder, the denset diamond film was deposited. Addition of oxygen in the gas mixture of methane and hydrogen improved the crystallinity of the deposited diamond film and also increased the deposition rate of the diamond film more than two times.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2020-2024
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• 2007

The article reports the synthesis of a novel bispyridino-18-crown-6 ether, 7-{[(5S,15S)-5,15-diphenyl- 3,6,14,17-tetraoxa-23,24-diazatricyclo[17.3.1.18,12]tetracosa-1(23),8(24),9,11,19,21-hexaen-10-yl]oxy}heptylferrocenamide 6, bearing the C2-symmetric diphenyl substituents as chiral barriers and the ferrocenyl groups serving as an electrochemical sensor, and its electrochemical study with D- and L-AlaOMe·HCl as the guest by cyclovoltametry.

• Journal of the Korean Chemical Society
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• v.57 no.3
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• pp.341-351
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• 2013

Zn(II), Cd(II) and Hg(II) complexes with a general composition[$M(L)_2(X)_2$], where L=4-aminopyridine (4AP) and $X=NO_2{^-}$ were prepared under microwave irradiation. The metal complexes were characterized by elemental analyses, molar conductance, IR, Far-IR, electronic, NMR ($^1H$, $^{13}C$), XPS spectral and thermal studies. The spectroscopic studies reveal the composition, different modes of bonding, electronic transition, different chemical environment of C and H atoms and the electronic state of the metal atoms. On the basis of the characterization data, tetrahedral geometry is suggested for all the complexes. The free ligand (4-aminopyridine) and their metal complexes were screened against phytopathogenic fungi and bacteria in vitro and the activities were compared.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.119-121
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• 2004

A new and efficient synthesis of the novel bioactive bis(benzopyrano) fused dihydropyridines is described. The conventionally developed route is a two step multicomponent condensation reaction. This is latter modified by a one pot microwave (MW) assisted reaction using inorganic solid support via the arylidene derivative intermediate. With this environmentally benign approach, the reaction time is brought down from hours to minutes along with a yield enhancement. Furthermore, the role of different solid supports is studied and it is concluded that the acidic alumina is the best solid support for the present investigation.

• Korean Journal of Materials Research
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• v.34 no.8
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• pp.387-394
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• 2024

Transition metal oxide-based materials have mainly been studied as electrodes for energy storage devices designed to meet essential energy demands. Among transition metal oxide-based materials, hydrated vanadium pentoxide (V₂O₅·nH₂O), a vanadium oxide material, has demonstrated great electrochemical performance in the electrodes of energy storage devices. Graphene oxide (GO), a carbon-based material with high surface area and high electrical conductivity, has been added to V₂O₅·nH₂O to compensate for its low electrical conductivity and structural instability. Here, V₂O₅·nH₂O/GO nanobelts are manufactured with water without adding acid to ensure that the GO is uniformly dispersed, using a microwave-assisted hydrothermal synthesis. The resulting V₂O₅·nH₂O/GO nanobelts exhibited a high specific capacitance of 206 F/g and more stable cycling performance than V₂O₅·nH₂O without GO. The drying conditions of the carbon paper electrodes also resulted in more stable cycling performance when conducted at high vacuum and high temperature, compared with low vacuum and room temperature conditions. The improvement in electrochemical performance due to the addition of GO and the drying conditions of carbon paper electrodes indicate their great potential value as electrodes in energy storage devices.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.525-533
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• 2014

ZnO has attracted much attention such as photocatalysts, sensors, piezoelectricity and etc. At present, an economical and rapid synthesis route based on the efficient microwave polyol process is used to synthesized metal-doped ZnO nanoclusters. Diethylene glycol has a property of high polarizability, and is an excellent microwave absorbing agent, thus leading to a high heating rate and a significantly shorter reaction time. In this study, metal-doped ZnO nanoclusters are obtained with different seed volumes, when zinc acetate dihydrate is used as a precursor, and metal acetate hydrate is used as a doped-metal and diethylene glycol is used as a solvent. The obtained metal-doped ZnO nanoclusters were characterized by FE-SEM, XRD, Raman and PSA.