• Title/Summary/Keyword: Microwave-irradiation

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Removal of SF6 over Silicon Carbide with Aluminium Oxide by Microwave Irradiation (마이크로웨이브 조사에 따른 산화알루미늄이 함유된 실리콘카바이드의 SF6 제거)

  • Choi, Sung-Woo
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.4
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    • pp.240-246
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    • 2013
  • $SF_6$ is the most important greenhouse gas with the highest GWP (global warming potential). The $SF_6$ decomposition study was performed with silicon carbide with aluminium oxide by microwave irradiation. DRE (Decomposition and Removal Efficiencie) of $SF_6$ were evaluated by GC-TCD unit using 3,000 ppm $SF_6$ gas. DRE of $SF_6$ was increased by $Al_2O_3$ contents to 10~30 wt%, otherwise $Al_2O_3$ content of 40~50 wt% was decreased. DRE of $SF_6$ up to 99.99% have been achieved in SiC-$Al_2O_3$ (20 wt%) and SiC-$Al_2O_3$ (30 wt%) above $900^{\circ}C$. Also, the DRE of SiC-$Al_2O_3$ (30 wt%) at $700^{\circ}C$ showed 96.72%. In addition to consideration microwave input energy and $Al_2O_3$ content, SiC-$Al_2O_3$ (30 wt%) can be suggested the best material to control $SF_6$. The results of this study suggest it is important to control content of $Al_2O_3$ in SiC for decomposition of $SF_6$ with microwave energy.

Optimization of microwave-assisted extraction process for blue honeysuckle (Lonicera coerulea L.) using response surface methodology (반응표면분석법을 이용한 댕댕이 기능성성분의 마이크로웨이브추출조건 최적화)

  • Park, Daehee;Lee, Jae-Jun;Park, Jongjin;Park, Sanghwan;Lee, Wonyoung
    • Food Science and Preservation
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    • v.24 no.5
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    • pp.623-630
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    • 2017
  • Functional compounds including flavonoids, anthocyanins, polyphneols and antioxidants were extracted from blue honeysuckle (Lonicera caerulea L.) using highly efficient microwave-assisted extraction. And extraction process was modeled and optimized according to response surface methodology (RSM). The independent variables ($X_n$) were ethanol concentration ($X_1$: 0, 25, 50, 75, 100%), irradiation time ($X_2$: 1, 3, 5, 7, 9 min), and microwave power ($X_3$: 60, 120, 180, 240, 300 W). Dependent variables ($Y_n$) were total flavonoid contents ($Y_1$), total anthocyanin contents ($Y_2$), total polyphenol contents ($Y_3$) and antioxidant activity ($Y_4$). Four-dimensional response surface plots were generated based on the fitted second-order polynomial models to get optimal conditions. Estimated optimal conditions for 4 responses were ethanol concentration of 54-72%, irradiation time of 7.1-7.6 min, and microwave power of 243-251 W. Ridge analysis predicted the maximal responses of total flavonoid content, total anthocyanin content, total polyphenol content and antioxidant activity were 38.00 mg RE/g, 6.80 mg CGE/g, 14.90 mg GAE/g, 89.10%, respectively. Verification experiment was carried out at predicted optimal conditions and experimental values for total flavonoid content, total anthocyanin content, total polyphenol content and antioxidant activity were 38.10 mg RE/g, 6.72 mg CGE/g, 14.91 mg GAE/g and 89.13%, respectively. No significant difference was observed between predicted and experimental values, indicating good fitness of fitted model and successful application of RSM.

Changes of Pork Antigenicity by Heat, Pressure, Sonication, Microwave, and Gamma Irradiation (물리적 처리에 의한 돼지고기의 항원성 변화)

  • Kim, Seo-Jin;Kim, Koth-Bong-Woo-Ri;Song, Eu-Jin;Lee, So-Young;Yoon, So-Young;Lee, So-Jeong;Lee, Chung-Jo;Park, Jin-Gyu;Lee, Ju-Woon;Byun, Myung-Woo;Ahn, Dong-Hyun
    • Food Science of Animal Resources
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    • v.29 no.6
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    • pp.709-718
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    • 2009
  • The purpose of this study was to search for physical treatments to reduce allergenicity of pork. Physical treatments such as heating, autoclave, microwave, sonication, and irradiation have been used for food processing or reduction of allergenicity. The porcine serum albumin (PSA), known as a major allergen in pork, was extracted after physical treatments. The antigenicity of pork extracts by heating (80 and $100^{\circ}C$ for 20 min), autoclave ($121^{\circ}C$ for 5, 10, and 30 min), and microwave (for 5 and 10 min) was significantly decreased. Especially, the binding ability of p-IgG to pork extracts by autoclave for 30 min showed the greatest decrease (about 3%) in physical treatments. However, the antigenicity of pork was unaffected by sonication and irradiation treatment. These results indicated that the autoclave treatment was the most effective method to reduce the antigenicity of pork.

Microwave-assisted Fenton degradation of methylene blue (마이크로웨이브를 이용한 메틸렌 블루의 펜톤산화)

  • Kim, Shin-Young;Ahn, Johng-Hwa
    • Journal of Industrial Technology
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    • v.37 no.1
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    • pp.21-26
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    • 2017
  • This work experimentally determined the effect of combining of microwave irradiation and the Fenton process on decolorization of methylene blue ($C_{16}H_{18}N_3SCl$, MB). As [$H_2O_2$] increased from 2.65 to 4.41 mM, the decolorization of MB increased from 22.7 to 99.1%. As [$Fe^{2+}$] increased from 0.07 to 0.18 mM, the decolorization of MB increased from 24.0 to 98.5%. MB removal efficiencies were ${\geq}95%$ at $[H_2O_2]{\geq}3.5mM$ and $3.5{\leq}[H_2O_2]/[Fe^{2+}]{\leq}17.3$, but $[H_2O_2]/[Fe^{2+}]{\geq}20$ caused a decrease in MB removal. A two-stage kinetic model matched the experimental data well.

Microwave Assisted Reaction of Condensed Thiophenes With Electron Poor Olefins

  • Al-zaydi, Khadijah M.;Elnagdi , Mohamed H.
    • Journal of the Korean Chemical Society
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    • v.47 no.6
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    • pp.591-596
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    • 2003
  • Aminothienopyridazines 1a, b and aminothienocoumarin 2 condensed with DMFDMA to yield amidines 3a, b and 4. These compounds reacted with N-phenylmaleimide to yield 9 and 10. On the other hand reacting 3a, b, 4, 18, 19 and 20 with maleic anhydride afforded only the formylated derivatives 5a, b, 6, 21, 22 and 23 respectively. The reaction of 3a, b with diethyl fumarate afforded 11, formed most likely via hydrolysis of the amidine 14 during working up the reaction mixture. Irradiation of N-phenylmaleimide in microwave oven afforded [2+2] and [2+2+2] cycloaddition product.

Effect of Active Synthetic 2-Substituted Quinazolinones on Anti-Platelet Aggregation and the Inhibition of Superoxide Anion Generation by Neutrophils

  • Chang, Fang-Rong;Wu, Chin-Chung;Hwang, Tsong-Long;Patnam, Ramesh;Kuo, Reen-Yen;Wang, Wei-Ya;Lan, Yu-Hsuan;Wu, Yang-Chang
    • Archives of Pharmacal Research
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    • v.26 no.7
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    • pp.511-515
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    • 2003
  • Quinazolinones, 2-substituted and 3-substituted, mainly synthesized by microwave irradiation, were subjected to anti-platelet aggregation and inhibition of superoxide anion generation assays. Interestingly, 2-phenyl-4-quinazolinone (4) exhibited significant inhibitory activities toward platelet aggregation and neutrophil activation, and it might therefore serve as a prototype lead compound.

Effect of Temperature-increase Rate and Terminal Temperature on the Solubilization of Sewage Sludge using Microwave Irradiation

  • Park, Woon-Ji;Ahn, Johng-Hwa;Lee, Chan-Ki
    • Environmental Engineering Research
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    • v.14 no.1
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    • pp.48-52
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    • 2009
  • Solubilization of sewage sludge creates favorable conditions for anaerobic microorganisms to produce biogas. In this paper, we quantify the effect of heating pretreatment on the degree of solubilization of sewage sludge. The pretreatment process was carried out using a lab-scale industrial microwave unit (2450 MHz frequency). Response surface analysis was applied to determine the combination of temperature-increase rate (ramp rate) (2.9 to 17.1 ${^{\circ}C}$/min) and terminal temperature (52 to 108${^{\circ}C}$). Both ramp rate and temperature significantly affected the solubilization degree of sludge. Within the design boundaries, the conditions predicted to maximize the solubilization degree of 15.8% were determined to be 2.9 ${^{\circ}C}$/min and 104${^{\circ}C}$.

Detectable frequency and sensitivity of high temperature superconducting Josephson junctions (고온초전도 조셉슨 접합의 고주파 검지 특성 연구)

  • Cho, Won-Il;Shim, Woo-Seok;Yoo, Jang-Hoon;Kim, Do-Hyon;Park, Gwang-Seo;Song, In-Sang
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.38-42
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    • 1999
  • We prepared hish T$_c$ Josephson junctions that have different I$_c\;'s$ and R$_n\;'s$ and studied their microwave properties. We measured the current-voltage characteristics of the junctions under the irradiation of 22 GHz electromagnetic wave at various temperatures. from the Shapiro steps, we calculated the maximum detectable frequency and the microwave received power of the junctions. Increasing critical current values increase both maximum detectable frequency and sensitivity. However, increasing temperature increase sensitivity but decrease maximum detectable frequency.

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Microwave-assisted Synthesis of Mixed Ligand Complexes of Zn(II), Cd(II) and Hg(II) Derived from 4-aminopyridine and Nitrite Ion: Spectral, Thermal and Biological Investigations

  • Dhaveethu, Karuthakannan;Ramachandramoorthy, Thiagarajan;Thirunavukkarasu, Kandasamy
    • 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.