• 대한화학회지
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• 제54권4호
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• pp.419-428
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• 2010

마이크로웨이브 반응 장치 (Synthos 3000 Aton Paar, GmbH, 1400 W maximum magnetron)를 이용하여, diisopropylcarbodiimide (DIC)/와 1-hydroxybenzotriazoles (HOXt) (X = A or B)를 반응시켜서 amino acid hydrazide를 효율적으로 합성할 수 있는 반응 조건을 개발하였다. 일반적인 가열반응과 마이크로웨이브 반응을 반응 시간, 반응 조건 등을 비교하였을 때에, 마이크로웨이브 반응이 보다 효율적으로 진행되었으며, diisopropylcarbodiimide (DIC)와 1-hydroxybenzotriazole (HOBt) 반응에서보다는 diisopropylcarbodiimide (DIC)와 7-aza-1-hydroxybenzotriazole (HOAt)를 반응시켰을 때에 좋은 수율 (95 - 98%)로 얻어졌다.

• Korean Chemical Engineering Research
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• 제59권2호
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• pp.260-268
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• 2021

Adsorption is the most promising technology used to adsorb CO2 to reduce its concentration in the atmosphere due to its functional effectiveness. Various porous materials have been extensively synthesized to boost CO2 adsorption efficiency, for example, zeolite. Here, we report the synthesis process of zeolite adsorbent impregnated with amine, combining the benefit of these two substances. We compared conventional heating with microwave-assisted heating by varying concentrations of monoethanolamine in methanol (10% v/v and 40% v/v) as a liquid solution. The results showed that monoethanolamine impregnation helps significantly increase adsorption capacity, where adsorption occurs as a physisorption and not as chemisorption due to the adsorbent's steric hindrance effect. The highest adsorption capacity of 0.3649 mmol CO2 / gram adsorbent was reached by microwave exposure for 10 minutes. This work also reveals that a decrease in CO2 adsorption capacity was observed at a longer exposure period, and it reached a constant 40-minute adsorption rate. Impregnating activated zeolite with 40% monoethanolamine for 10 minutes in addition to microwave exposure (0.8973 mmol CO2 / gram adsorbent) is the maximum adsorption ability achieved.

• 한국재료학회지
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• 제17권12호
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• pp.669-675
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• 2007

Hydroxyapatite (HAp) and biphasic calcium phosphate (BCP) nano powders were synthesized using the microwave-assisted synthesis process dependent on pH and microwave irradiation time. The average size of a powder was less than 100 nm in diameter. Through in-vitro cytotoxicity tests by an extract dilution method, the HAp and BCP nano powders have shown to be cytocompatible for L-929 fibroblast cells, osteoblastlike MG-63 cells and osteoclast-like Raw 264.7 cells. The activation of osteoblast was estimated by alkaline phosphatase (ALP) activity. When the HAp and BCP were treated to MG-63 cells, alkaline phosphatase activities increased on day 3, compared with those of the untreated cells. Also, the collagen fibers increased when the HAp and BCP powders suspension were treated to MG-63 cells, compared to those of the untreated cells. Quantitative alizarin red S mineralization assays showed a trend toward increasing mineralization in osteoblast cultured with powder suspension. In conclusion, hydroxyapatite and biphasic calcium phosphate appeared to be a bone graft substitute material with optimal biocompatibility and could be further applied to clinical use as an artificial bone graft substitute.

• 한국응용과학기술학회지
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• 제31권3호
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• pp.525-533
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• 2014

금속이 도핑 된 산화아연 나노클러스터를 합성하기 위해 마이크로웨이브를 이용한 폴리올 공정은 빠르고 경제적인 합성 방법이다. 디에틸렌글리콜은 높은 분극률과 마이크로파의 흡수 능력이 뛰어나며, 높은 온도상승 비율과 반응시간을 짧게 해준다. 본 연구에서는 금속이 도핑 된 산화아연 나노클러스터를 합성하기 위해서 첨가되는 seed의 부피비를 다르게 하여 얻었으며, 전구체로는 아세트산 아연 2수화물, 도핑 금속은 아세트산 금속 염을 그리고 용매로서 디에틸렌글리콜을 사용하였다. 금속이 도핑된 산화아연 클러스터는 FE-SEM, XRD, Raman, PSA로 특성을 확인하였다.

• Elastomers and Composites
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• 제39권4호
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• pp.309-317
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• 2004

풀러렌[$C_{70}$]을 3-chloroperoxy benzoic acid, chromium (VI) oxide, benzoyl peroxide, trichloroisocyanuric acid 등의 산화제를 사용하여 마이크로파 조건에서 반응시켜 풀러렌 난화물[$C_{70}O_n$] ($n=1{\sim}3$ or n=1)을 합성하였다. 동일한 마이크로파 조건에서 여러가지 산화제와 풀러렌[$C_{70}$]의 고체상태 반응성은 3-chloroperoxy benzoic acid > chromium(VI) oxide > trichloroisocyanuric acid $\simeq$ benzoyl peroxide 순으로 증가함을 나타냈다. MALDI-TOF-MS, UV-visible, 그리고 HPLC를 사용하여 분석한 결과 생성된 풀러렌 산화물은 [$C_{70}O_n$] ($n=1{\sim}3$ or n=1)임을 알 수 있었다.

• 공업화학
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• 제22권2호
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• pp.214-218
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• 2011

마이크로파 가열 방법과 기존의 가열 방법을 이용하여 석탄회로부터 제올라이트 A를 합성하였다. 반응시간, sodium aluminate의 양, 반응 온도 등이 제올라이트 A의 결정화에 미치는 영향에 대해 연구하였다. $80{\sim}100^{\circ}C$의 범위에서 제올라이트 A의 합성에 필요한 반응 시간은 3~6 h이었으며, 6 h 이상이 되면 결정화도가 오히려 감소하였다. 제올라이트 A의 합성에 필요한 sodium aluminate의 양은 $90^{\circ}C$ 이상에서는 합성용액의 $SiO_2/Al_2O_3$의 비가 0.44~1.05에서 최적이었으며, $80^{\circ}C$에서는 더 많은 양이 필요하였다. 마이크로파 가열 방법은 기존의 가열 방법에 비해 초기 결정화 속도는 약간 증가하였으나, 충분히 결정화되는데 필요한 반응시간은 서로 비슷하였다. 따라서 마이크로파 가열에 의한 석탄회로부터 제올라이트 A의 합성에 미치는 영향은 크지 않다는 것을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1219-1222
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• 2010

A simple and efficient method has been developed for conversion of arenecarbaldehyde-3-methylquinoxalin-2-ylhydrazones to 3-(2-methylquinoxalin-3-yl)-2-(substitutedphenyl)thiazolidin-4-ones in good yields using microwave irradiation technique on silica as solid support under solvent free conditions. The synthesized compounds were characterized by elemental microanalysis, infrared spectroscopy, $^1H$ NMR, and mass spectroscopy. All the synthesized thiazolidinones were investigated for their antimicrobial and antifungal activities. The results of the biological activities revealed that the compounds 3b, 3d, 3f and 3h exhibited excellent antibacterial activities while 3d and 3h exhibited good antifungal activity.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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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%.

• Transactions on Electrical and Electronic Materials
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• 제16권4호
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• pp.198-200
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• 2015

The microwave plasma enhanced chemical vapor deposition (PECVD) system was used to grow a carbon nanowall (CNW) on a silicon (Si) substrate with hydrogen (H₂) and methane (CH₄) gases. To find the growth mechanism of CNW, we increased the growth time of CNW from 5 to 30 min. The vertical and surficial conditions of the grown CNWs according to growth time were characterized by field emission scanning electron microscopy (FE-SEM). Energy dispersive spectroscopy (EDS) measurements showed that the CNWs consisted solely of carbon.

• 한국세라믹학회지
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• 제32권9호
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• pp.1009-1018
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• 1995

(Ti.Si)C composite powders were synthesized by SHS method using microwave energy. Compositional and structural characterization of the powder were carried out by using scanning electron microscopy and X-ray diffraction. The average particle size of the synthesized (Ti.Si)C composite powders was smaller than that of the starting materials. From the results of the temperature profile, combustion temperature and velocity were decreased with increasing Si molar ratio. With increasing C molar ratio combustion temperature and velocity did not change. (Ti.Si)C composite was sintered at 185$0^{\circ}C$ for 60 min by using hot-pressing with 30 MPa. The best properties were obtained from the sintered specimen whose composition was 1 : 1 : 1.9 molar ratio of Ti : Si : C. The sintering density, flexural strength and vickers hardness of the sintered body were 4.71 g/㎤, 423 MPa and 21 GPa, respectively.