• 제목/요약/키워드: Microwave synthesis

검색결과 235건 처리시간 0.027초

Synthesis of White Diamond Thin Film by Microwave Plasma Enhanced Chemical Vapor Deposition Method

  • Kim, S.H.;Y.S.ppark;Lee, J-W.;Song, S.A.
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 1994년도 제6회 학술발표회 논문개요집
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    • pp.98-101
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    • 1994
  • white diamond thin film, which should be compposed of almost ppure diamond, could be successfully obtained under high ppressure conditions(above 150 Torr) by means of MppECVD(microwave pplasma enhanced chemical vappor depposition, ASTeX 1.5 kW). Characteristics of the films with varing expperimental pparameters have been examined. From the expperimental results, we will discuss the surface morpphology and the growth mechanism of the films.

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Flux법에 의한 알파 알루미나 판상체의 마이크로파 합성 (Microwave Synthesis of Alpha Alumina Platelets Using Flux Method)

  • 박성수;김준호;김성완;이성환;박재현;박희찬
    • 한국세라믹학회지
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    • 제39권5호
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    • pp.473-478
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    • 2002
  • Flux법과 마이크로파 가열법으로 $Al_2(SO_4)_3+2Na_2SO_4$${\gamma}-Al_2O_3+2Na_2SO_4$ 분말혼합물로부터 ${\alpha}-Al_2O_3$ 판상체(platelets)를 합성하였다. ${\alpha}-Al_2O_3$ 판상체 형성에 미치는 마이크로파의 영향을 조사하기 위하여 DTA-TG, XRD 및 SEM을 이용하였다. $Al_2(SO_4)_3+2Na_2SO_4$ 혼합물의 경우, 마이크로파로 가열된 시료는 재래식으로 가열된 시료에 비하여 입자의 크기가 작고 응집체로 구성된 ${\alpha}-Al_2O_3$ 판상체로 나타났다. ${\gamma}-Al_2O_3+2Na_2SO_4$ 혼합물의 경우, 마이크로파 가열에 의한 ${\alpha}-Al_2O_3$ 판상체 형성온도는 재래식 가열에 의한 형성온도 보다 낮았다. 또한 마이크로파로 가열된 시료의 형상은 재래식으로 가열된 시료의 형상과 유사하였다. 그러나 마이크로파로 가열된 시료는 재래식으로 가열된 시료에 비하여 입자의 크기가 작았다.

Direct Microwave Sintering of Poorly Coupled Ceramics in Electrochemical Devices

  • Amiri, Taghi;Etsell, Thomas H.;Sarkar, Partha
    • Journal of Electrochemical Science and Technology
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    • 제13권3호
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    • pp.390-397
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    • 2022
  • The use of microwaves as the energy source for synthesis and sintering of ceramics offers substantial advantages compared to conventional gas-fired and electric resistance furnaces. Benefits include much shorter processing times and reaching the sintering temperature more quickly, resulting in superior final product quality. Most oxide ceramics poorly interact with microwave irradiation at low temperatures; thus, a more complex setup including a susceptor is needed, which makes the whole process very complicated. This investigation pursued a new approach, which enabled us to use microwave irradiation directly in poorly coupled oxides. In many solid-state electrochemical devices, the support is either metal or can be reduced to metal. Metal powders in the support can act as an internal susceptor and heat the entire cell. Then sufficient interaction of microwave irradiation and ceramic material can occur as the sample temperature increases. This microwave heating and exothermic reaction of oxidation of the support can sinter the ceramic very efficiently without any external susceptor. In this study, yttria stabilized zirconia (YSZ) and a Ni-YSZ cermet support were used as an example. The cermet was used as the support, and a YSZ electrolyte was coated and sintered directly using microwave irradiation without the use of any susceptor. The results were compared to a similar cell prepared using a conventional electric furnace. The leakage test and full cell power measurement results revealed a fully leak-free electrolyte. Scanning electron microscopy and density measurements show that microwave sintered samples have lower open porosity in the electrode support than conventional heat treatment. This technique offers an efficient way to directly use microwave irradiation to sinter thin film ceramics without a susceptor.

친환경적 One Pot 합성, In Vitro에서 Morpholino Pyrimidines의 분광학적 특성과 항균성 및 항진균성 (A Green Chemical Approach towards the 'One-Pot' Synthesis, Spectral Characterization and in Vitro Antibacterial and Antifungal Activities of Morpholino Pyrimidines)

  • Kanagarajan, V.;Thanusu, J.;Gopalakrishnan, M.
    • 대한화학회지
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    • 제53권6호
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    • pp.731-741
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    • 2009
  • $NaHSO_4.SiO_2$ 촉매를 이용한 microwave 및 무수조건하에서 새로운 morpholino pyrimidines의 One-pot합성이다. 합성된 모든 화합물을 이용하여 in vitro에서 임상학적인 단리된 박테리아 품종 즉 Bacillus subtilis, Bacillus cerues, Micrococcus luteus , Salmonella typhii에 대해 항균성을 살펴보았고, 균품종 즉 Aspergillus niger, Candida 6, Candida 51에 대해 항진균성을 살펴보았다. 미생물 결과에 대한 합성된 화합물의 구조적 활동성의 관련성에 대해 토론하였다.

Synthesis of Calcium Phosphate Minerals from Biowaste Clam Shells Using Microwave Heating

  • Bramhe, Sachin;Ryu, Jae-Kyung;Chu, Min Cheol;Balakrishnan, Avinash;Kim, Taik Nam
    • 한국재료학회지
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    • 제24권12호
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    • pp.700-703
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    • 2014
  • Calcium phosphate minerals are biologically important because of their application in the fields of orthopaedics and dentistry. Herein we have tried to synthesize calcium phosphate minerals from biowaste clam shells. A simple microwave method was used to synthesize a mixture of calcium phosphate minerals such as hydroxyapatite, tri-calcium phosphate, and monetite. The microwave induces vibration of the dipole ions in the reagent. The heating and rearrangement of ions and atoms occurs during the process. The phases obtained in the final powder were ascertained by X-ray diffraction; the morphology of each sample was checked using a scanning electron microscope. We were able to obtain a mixture of calcium phosphate minerals using the microwave method; the calcined powder showed a brick like morphology, which is different from the rod shape morphology of the hydroxyapatite obtained using the hydrothermal process.