• 제목/요약/키워드: Microwave irradiation

검색결과 286건 처리시간 0.021초

하수 일차슬러지의 세정산발효 특성에 대한 Microwave 전처리의 영향 (Effects of Microwave Irradiation for Elutriated Acid Fermentation of Sewage Primary Sludge)

  • 권구호;이원식;민경석
    • 한국물환경학회지
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    • 제23권4호
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    • pp.498-503
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    • 2007
  • The performance of elutriated acid fermentation to evaluate the effects of microwave irradiation and pH control as pretreatment was investigated. The MW pH 7 reactor which was used the pretreated primary sludge as microwave irradiation was operated at pH 7 and $35^{\circ}C$. The EAF pH 9 reactor was operated at pH 9 and $35^{\circ}C$ without pretreatment. The SCOD and VFAs production rate were 0.17 gSeOD/gVSrem. and 0.27 gVFAs as COD/gVSrem. in MW pH 7 reactor, 0.16 gSCOD/gVSrem. and 0.24 gVFAs as COD/gVSrem. in EAF pH 9 reactor, respectively. VS and Volume reduction were 54% and 48% in MW pH 7 reactor, 54.6% and 36% in EAF pH 9 reactor, respectively. A comparison of the microwave irradiation and controlled pH in elutriated acid fermentation showed that the former is more efficient in SCOD and VFAs production and it rises to slightly higher reduction in the volume of the sludge. In addition, E. coli. was not detected in the wasting sludge of MW pH 7 reactor. Based on the results, microwave irradiation appeared to be one of the viable options for generating class A sludge. According to the batch tests, sequencing batch test which was used the pretreated primary sludge as microwave was performed at pH 7 and $35^{\circ}C$, SCOD production was 0.16 gSCOD/gVSrem., VS reduction and volume reduction were 64% and 63%, respectively.

The effect of microwave irradiation on the acidogenesis of waste activated sludge

  • 박병철;안종화;황석환
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2003년도 생물공학의 동향(XII)
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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.

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방사선 조사, 가열 및 마이크로웨이브처리에 따른 Ascorbic Acid의 함량변화 (Changes of Ascorbic Acid Contents Induced from Gamma Irradiation, Heating and Microwave Treatments)

  • 변명우;이인숙;이경행;육홍선;강근옥
    • 한국식품영양과학회지
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    • 제28권4호
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    • pp.954-957
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    • 1999
  • The changes in L ascorbic acid content by processing treatments; gamma irradiation, heating and microwave were investigated using high performance liquid chromatography. The content of L ascorbic acid in standard solutions and citrus fruits decreased from 27.4 to 44.9% and from 6.9 to 21.9%, re spectively, by gamma irradiation doses in the range of 1 to 10 kGy. By heating treatments, L ascorbic acids in standard solutions and citrus fruits were destroyed 22.5 to 36.8% and 4.5 to 18.1%, respectively. By microwave treatment, L ascorbic acid content also decreased from 23.1 to 47.4% and from 6.5 to 22.6%, respectively.

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Coherent motion of microwave-induced fluxons in intrinsic Josephson junctions of HgI$_2$-intercalated Bi$_2$Sr$_2$C aCu$_2$O$_{8+x}$ single crystals

  • Kim, Jin-Hee;Doh, Yong-Joo;Chang, Sung-Ho;Lee, Hu-Jong;Chang, Hyun-Sik;Kim, Kyu-Tae;Jang, Eue-Soon;Choy, Jin-Ho
    • 한국초전도학회:학술대회논문집
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    • 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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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.

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마이크로파처리에 의한 심황색소의 화학안정성 및 세포독성 변화 (Changes in chemical properties and cytotoxicity of turmeric pigments by microwave treatment)

  • 송이슬;홍정일
    • 한국식품과학회지
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    • 제49권6호
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    • pp.693-698
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    • 2017
  • 다양한 생리활성을 가진 심황과 쿠쿠미노이드가 가공식품류 등에 광범위하게 적용되는 바, 실제 식품 중에 이용되는 oleoresin turmeric 색소에 대해 마이크로파처리에 의한 화학안정성 및 생리활성의 변화를 분석하였다. 심황색소는 마이크로파 가열처리에 의해 황색도와 화학안정성이 감소하였으며 특히 3종의 쿠쿠미노이드 중 쿠쿠민이 마이크로파처리에 가장 민감하였고 BMC가 가장 안정하였다. 마이크로파처리 후 심황색소의 ABTS, AAPH peroxyl radical 및 아질산염 제거활성은 증가하였으며, DPPH 라디칼 제거활성에는 변화가 없었다. 심황색소에서 생성되는 활성 산소종은 마이크로파처리 후 증가하였으나, 정상장관계 세포 INT 407과 대장암 세포 HCT 116을 대상으로 한 세포독성 효과는 두 종류의 세포에서 모두 약화되었다. 본 연구에서는 다양한 식품 중에 첨가되는 심황색소가 마이크로파처리에 의해 화학적변화 및 생리활성에 영향을 가져올 수 있음을 보여주며, 이를 함유한 식품의 적절한 가공 및 조리방법이 고려되야 함을 제시하고 있다.

Microwave와 Solution ZrO2를 이용한 Metal-Oxide-Semiconductor-Capacitor 제작

  • 이성영;김승태;조원주
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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    • pp.206.1-206.1
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    • 2015
  • 최근에 금속산화물을 증착하는 방법으로 용액공정이 주목 받고 있다. 용액 공정은 대기압에서 매우 간단한 방법으로 복잡한 공정과정을 요구하지 않기 때문에 박막을 경제적으로 간단하게 형성할 수 있다. 하지만 용액공정을 통해 형성한 박막에는 소자의 특성을 열화 시키는 solvent와 탄소계열의 불순물을 많이 포함하고 있어 고온의 열처리가 필수적이다. 박막의 품질을 향상시키기 위해서 다양한 열처리 방법들이 이용되고 있으며, 일반적인 열처리 방법으로는 furnace를 이용한 conventional thermal annealing (CTA)이 많이 이용되고 있다. 하지만, 최근에는 microwave를 이용한 공정이 주목 받고 있다. Microwave energy는 CTA보다 효과적으로 비교적 낮은 온도에서 높은 열처리 효과를 나타낸다. 본 실험은 n-type Silicon 기판에 solution-ZrO2 산화막을 형성 후, oven baking을 한 뒤, CTA와 microwave를 이용하여 solvent와 불순물을 제거 하였다. 전기적 특성을 확인하기 위해 solution ZrO2 산화막 위에 E-beam evaporator를 이용해 Ti 금속 전극을 증착하여 Metal-Oxide-Semiconductor (MOS) capacitor를 제작하였다. 다음으로, PRECISION SEMICONDUCTOR PARAMETER ANALYZER (4156B)를 이용하여, capacitance-voltage (C-V) 특성 및 current-voltage (I-V) 특성을 비교하였다. 다음으로, CTA를 통하여 제작한 소자와 전기적 특성을 비교하였다. 그 결과, Microwave irradiation으로 열처리한 MOS capacitor 소자에서 capacitance 값과 flat band voltage, hysteresis 등이 개선되는 효과를 확인하였다. Microwave irradiation 열처리는 100oC 미만의 온도에서 공정이 이루어짐에도 불구하고 시료 내에서의 microwave 에너지의 흡수가 CTA 공정에서의 열에너지 흡수보다 훨씬 효율적으로 이루어지며, 결과적으로 ZrO2 용액의 불순물과 solvent를 낮은 온도에서 제거하여 고품질 박막 형성에 매우 효과적이라는 것을 나타낸다. 따라서, microwave irradiation 열처리 방법은 비정질 산화막이 포함되는 박막 transistor 소자 제작에 대하여 결정적인 열처리 방법이 될 것으로 기대한다.

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마이크로웨이브 조사와 Diisopropylcarbodiimide (DIC)/7-Aza-1-hydroxybenzotriazole (HOAt): N-Protected Amino Acid와 Hydrazine으로부터 다양한 Hydrazide합성을 위한 반응조건 (Microwave Irradiation and Diisopropylcarbodiimide (DIC)/7-Aza-1-hydroxybenzotriazole (HOAt): A Potent Combination for Synthesis of Variuos Hydrazide from N-Protected Amino Acid and Hydrazine)

  • Albatal, Mona;Ghani, Mohamad Abdul;El-Faham, Ayman;Al-Hazimi, Hassan M.;Hammud, Hassan H.
    • 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.

마이크로파 조사에 의한 SF6 분해시 Al2O3 첨가의 영향 (Effect of Al2O3 Addition on SF6 Decomposition by Microwave Irradiation)

  • 최성우
    • 한국환경과학회지
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    • 제22권1호
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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.