• 한국분말재료학회지
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• 제16권3호
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• pp.203-208
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• 2009

$Y_2O_3$:Eu red phosphor was prepared by microwave synthesis. The crystal phase, particle morphology, and luminescent properties were characterized by XRD, SEM, and spectrofluorometer, respectively. The prepared $Y_2O_3$:Eu particles had good crystallinity and strong red emission under ultravioletet excitation. The crystallite size increased with calcination temperature and satuarated at $1200^{\circ}C$. The primary particle size initially formed was varied from 30 to 450 nm with microwave-irradiation (MI) time. It was found that the emission intensity of $Y_2O_3$:Eu phosphor strongly depends on the MI time. In terms of the emission intensity, it was recommended that the MI time should be less than 15 min. The emission intensity of $Y_2O_3$:Eu phosphor prepared by microwave syntehsis strongly depended on the crystallite size of which an optimal size range was 50-60 nm.

• 한국결정성장학회지
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• 제18권4호
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• pp.169-173
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• 2008

본 연구에서는 자외선 영역에서 우수한 발광강도를 가지는 적색 형광체를 얻기 위하여 microwave 급속 열처리법으로 합성하여 $Eu^{3+}$와 $Bi^{3+}$가 도핑된 $YVO_4$의 발광특성을 관찰하였다. Microwave 급속 열처리시 입자의 크기는 매우 미세하며, 응집이 매우 심하였으나 열처리 유지시간이 증가할수록 입자 크기는 증가하고 응집현상은 개선되는 경향을 나타내었다. $YVO_4$: $Eu^{3+}$, $Bi^{3+}$ 적색 형광체의 발광 peak는 $Eu^{3+}$ ion의 영향에 의해 594.9 nm와 602.3 nm에서 $^5D_0{\longrightarrow}^7F_1$ 전자 천이에 의한 약한 발광 peak와 616.7 nm와 620.0 nm에서 $^5D_0{\longrightarrow}^7F_2$ 전자 천이에 의한 강한 발광 peak이 관찰 되었다. Microwave 급속 열처리법을 형광체 합성시 장시간 열처리 시간이 필요하지 않으면서 균일한 activator의 확산으로 인하여 발광특성을 향상시키는 것을 확인 할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1701-1705
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• 2005

We have established an efficient method for the synthesis of the arylpiperazine derivatives in which the acylation of 2-aminopyridine, the coupling reaction of the acyl compound with piperazines, and reduction of the arylpiperazines were performed under a microwave irradiation (300 W) to afford the corresponding target compounds in quantitative yields. In all cases, the reaction times were remarkably reduced when compared with those of the conventional method.

• 대한화학회지
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• 제55권3호
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• pp.486-489
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• 2011

Potassium dihydrogen phosphate는 마이크로파 조사조건에서 용매 없이 페놀과 아세토아세트산 에틸의 Pechmann 축합반응에 의하여 쿠마린을 합성하는 효과적인 촉매로 밝혀졌다. 이 방법은 쿠마린 합성에 있어서 소량의 촉매를 필요로 하며 수율이 높고, 반응이 깨끗할 뿐만 아니라 반응 시간이 짧은 장점들을 가지고 있다.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1863-1868
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• 2010

A simple and efficient synthesis of various $\alpha$-aminophosphonates (3a-l) by the reaction of substituted aromatic/heterocyclic aldehydes, 2-amino-6-methoxy-benzothiazole and dibutyl/diphenyl phosphites under microwave irradiation without catalyst was accomplished. The phosphonates were characterized by elemental analysis, IR, $^1H$, $^{13}C$- and $^{31}PNMR$ spectra. They showed promising antimicrobial, anti-oxidant activities depending on the nature of bioactive groups at the $\alpha$-carbon.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.2901-2905
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• 2014

The hierarchical-structured $LiFePO_4$ cathode materials were synthesized by one-step microwave synthesis, and their electrochemical properties were investigated. Addition of citric acid during the reaction lead to the formation of hierarchical structured $LiFePO_4$, which has both nano- and micron-characteristics advantageous for energy density and electrode fabrication. Adjusting the molar ratio of Fe to citric acid enhanced the electrochemical properties of $LiFePO_4$.

• ETRI Journal
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• 제28권2호
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• pp.223-226
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• 2006

This letter presents a new approach to synthesize the resonator filters of an arbitrary topology. This method employs an optimization method based on the relation between the polynomial coefficients of the transfer function and those of the $S_{21}$ from the coupling matrix. Therefore, this new method can also be applied to self-equalized filters that were not considered in the conventional optimization methods. Two microwave filters, a symmetric 4-pole filter with four transmission zeros (TZs) and an asymmetric 8-pole filter with seven TZs, are synthesized using the present method for validation. Excellent agreement between the response of the transfer function and that of the synthesized $S_{21}$ from the coupling matrix is shown.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2883-2886
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• 2009

A simple, highly efficient and environmentally benign method for the synthesis of 3-styrylchromones from 3-formylchromones and 4-nitrophenylacetic acid/4-nitrotolune in the presence of catalytic amount of basic ionic liquid 1-butyl-3-methylimidazolium hydroxide [(bmim)OH] carried out under the influence of microwave irradiation. This method gives remarkable advantages such as, short reaction times, simple work-up procedure and moderate to good yields. The ionic liquid was successfully reused for four cycles without significant loss of activity.

• Bulletin of the Korean Chemical Society
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• 제24권11호
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• pp.1575-1578
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• 2003

An environmentally benign approach for the synthesis of 2-substituted-4,6-diaryl pyrimidines using inorganic solid supports for its catalytic role as well as an energy transfer medium is described. The methodology eliminates the usage of solvent during the reaction. The reaction time is brought down from hours to minutes along with yield enhancement. The rate enhancement and high yield is attributed to the coupling of solvent free conditions with microwaves. Further, the role of base is studied in the reaction and it is concluded that microwave assisted basic alumina catalysed reaction is the best in terms of catalysis as well as reaction time and yield.

• Current Applied Physics
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• 제18권11호
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• pp.1410-1414
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• 2018

Magnetic nanoparticles (MNP) have attracted considerable interest in many fields of research and applied science due to their impressive properties. In the past, especially biomedical problems have promoted the development of MNPs. For technical applications e.g. wastewater treatment and absorption of electromagnetic waves, the existing synthesis approaches are too expensive and/or the producible quantities are too low. In this work we present a method for simple preparation of size-controlled magnetic iron oxide nanoparticles by electroerosion dispersion (EED) of carbon steel in water. We describe the synthesis method, the laboratory installation and discuss the structural, chemical and electromagnetic properties of the synthetized EED powders as well as their applicability for microwave absorption compared to other available ferrite powders.