• Title, Summary, Keyword: Microwave microscopy

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Growth Behavior of Aluminum Borate Whisker under 2.45 GHz Electromagnetic Irradiation (2.45 GHz 전자기파 조사하에서 Aluminum Borate Whisker의 성장 거동)

  • 김성완;이상근;김지경;이창희;안진모;신준식;박성수;박희찬
    • Journal of the Korean Ceramic Society
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    • v.40 no.10
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    • pp.998-1004
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    • 2003
  • With starting materials of two different powder mixtures, $Al_2$(S $O_4$)$_3$+xNa$_2$B$_4$ $O_{7}$$.$10$H_2O$(㏖ ratio; x=0.1, 0.7) and ${\gamma}$-Al$_2$ $O_3$+xNa$_2$B$_4$ $O_{7}$$.$10$H_2O$(㏖ ratio; x=0.1, 0.7), whisker-type $Al_{18}$B$_4$ $O_{33}$ particles were synthesized by using conventional and microwave heat-treatment. The effects of microwave, amount of flux and temperature on the growth of whisker-type $Al_{18}$B$_4$ $O_{33}$ particles were investigated by using X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM). With increase of heat-treatment temperature and amount of flux, the size of whisker-type $Al_{18}$B$_4$ $O_{33}$ particles increased in both conventional and microwave heat-treated samples. However, compared to the conventional heat-treated samples, whisker-type $Al_{18}$B$_4$ $O_{33}$ particles were well grown for the microwave heat-treated samples.ted samples.

Investigation of the interface between diamond film and silicon substrate using transmission electron microscopy (투과 전자 현미경을 이용한 다이아몬드 박막과 실리콘 기판의 계면 연구)

  • 김성훈
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.10 no.2
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    • pp.100-104
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    • 2000
  • Diamond film was deposited on Si substrate by using microwave plasma-enhanced chemical vapor deposition (MPECVD) system. After thinning the cross section between diamond film and Si substrate by ion milling method, we investigated its interface via transmission electron microscopy We could observe that the diamond film was grown either directly on Si substrate or via the interlayer between diamond film and Si substrate. Thickness of the interlayer was varied along the cross section. The interlayer might mainly composed of Sic andlor amorphous carbon. We could observe the well-developed electron diffraction pattern of both Si and diamond around the interface. Based on this result, we can conjecture the initial growth behavior of diamond film on Si substrate.

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Effect of FTO coated on stainless steel bipolar plate for PEM fuel cells

  • Park, Ji-Hun;Jang, Won-Yeong;Byeon, Dong-Jin;Lee, Jung-Gi
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.55.2-55.2
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    • 2009
  • A polymer electrolyte membrane (PEM) fuel cell has been getting large interest as a typical issue in useful applications. The PEMFC is composed of a membrane, catalyst and the bipolar plate. SnOx:F films on SUS316 stainless steel were prepared as a function of substrate with using electron cyclotron resonance-metal organic chemical vapor deposition (ECR-MOCVD) in order to achieve the corrosion-resistant and low contact resistance bipolar plates for PEM fuel cells. The SnOx:F films coated on SUS316 substrate at surface plasma treatment for excellent stability, before/after heat treatment for good crystalline structure and microwave power for were characterized by X-ray diffraction (XRD), auger electron microscopy (AES) and field emission-scanning electron microscopy (FE-SEM). The SnOx:F film coated on SUS316 substrate with various process parameters were able to observe optimum interfacial contact resistance (ICR) and corrosion resistance. It can be concluded that fluorine-doping content plays an important function in electrical property and characteristic of corrosion-protective film.

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Preparation of [C60]Fullerene-CoS2 Nanocomposites and Kinetics Study for Photocatalytic Degradation of Organic Dyes

  • Kim, Jae Jin;Ko, Weon Bae
    • Elastomers and Composites
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    • v.51 no.1
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    • pp.49-55
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    • 2016
  • Nanosized cobalt disulfide ($CoS_2$) particles were synthesized with 0.08 M cobalt chloride hexahydrate ($CoCl_2{\cdot}6H_2O$) and 0.2 M sodium thiosulfate pentahydrate ($Na_2S_2O_3{\cdot}5H_2O$) dissolved in distilled water under microwave irradiation. $[C_{60}]Fullerene-CoS_2$ nanocomposites were prepared with nanosized $CoS_2$ particles and [$C_{60}$]fullerene as heated by $700^{\circ}C$ for 2 h in an electric furnace. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) identified the heated $[C_{60}]fullerene-CoS_2$ nanocomposites. Heated $[C_{60}]fullerene-CoS_2$ nanocomposites were investigated the activity of photocatalytic degradation as a catalyst in various organic dyes like acid yellow 23, methylene blue, methyl orange, and rhodamine B with ultraviolet light at 254 nm by UV-vis spectrophotometer.

Study on the synthesis and the frequency response of HTS microwave device fabricated by pulsed laser deposition (레이저 공정을 이용한 초전도 통신소자 제작과 고주파특성 연구)

  • Park, Joo-Hyung;Jeong, Young-Sik;Lee, Sang-Yeol
    • Proceedings of the KIEE Conference
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    • pp.288-290
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    • 1997
  • Pulsed laser ablation has been used to fabricate superconducting $YBa_2Cu_3O_{7-x}$(YBCO) thin films on MgO substrates. The epitaxial YBCO thin films were grown at $750^{\circ}C$ and oxygen partial pressure of 200 mTorr. The electrical property and the characteristics of the YBCO thin films have been studied by R-T measurement. scanning electron microscopy (SEM) and X-ray diffraction (XRD). A microstrip line resonator has been fabricated using YBCO superconducting thin films by photolithography and wet-etch process. The resonator has linear microstrip line separated by a gap of 0.278 mm. We observed a fundamental resonance peak at the frequency of 10.007 GHz.

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A Study on the Development of Automatic Welding System using Solor Energy (태양에너지를 이용한 자동용접 시스템 개발에 관한 연구)

  • Kim I.S.;Kim O.S.;Son J.S.;Seo J.H.
    • Proceedings of the KIPE Conference
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    • pp.532-533
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    • 2006
  • In this research work attempts were made to study the bonding of thermoplastics with adhesives using solar energy. In order to study the curing behaviour necessary experiments were conducted under varying conditions of temperature, exposure time and power. The cured samples were then studied under the optical microscope before subjecting to tensile testing in order to study their mechanical properties. The fracture surfaces were further studied under the Scanning Electron Microscopy in order to study the microstructural changes that are taken place during curing. From the present study it is evident that curing under higher solar energy temperature, generally improves bond strength and quality of the adhesive joints when compared to other modes of curing process expect the microwave curing process.

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Terahertz dielectric characteristics of (Ba,Sr)$TiO_3$ thin films (테라헤르츠 영역에서의 BST 박막의 유전 특성 평가)

  • Cho, Kwang-Hwan;Kang, Chong-Yun;Yoon, Seok-Jin;Lee, Young-Pak;Maeng, In-Hee;Son, Joo-Hiuk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.28-28
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    • 2007
  • Ferroelectric $(Ba_{0.5}Sr_{0.5})TiO_3$ (BST) thin films of thickness 500nm were deposited on $LaAlO_3$, (LAO) substrates by at $800^{\circ}C$. BST films were characterized for structure using X-ray diffraction (XRD). The surface morphology and thickness of BST the films were characterized by atomic force microscopy (AFM) and field emission scanning electron microscope (FESEM). We measured the dielectric properties at microwave frequencies (1~3 GHz) using a symmetrical stripline resonator with shorted ends and terahertz frequencies (0.2~2.5 THz) using a time-domain terahertz spectroscopy. The real and imaginary parts of the complex dielectric constant of the BST thin films on LAO substrates were in agreement with those previously reported.

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Thermal Properties of Diamond Films Deposited by Chemical Vapor Depositon

  • Chae, Hee-Baik;Baik, Young-Joon
    • The Korean Journal of Ceramics
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    • v.3 no.1
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    • pp.29-33
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    • 1997
  • Four diamond films were deposited by the microwave plasma assisted chemical vapor deposition method varying CH4 concentration from 2.5 to 10% in the feeding gases. Thermal conductivity was measured on these free standing films by the steady state method from 80 K to 400K. They showed higher thermal conductivity as the film deposited with lower methane concentration. One exception, 7.79% methane concentration deposited film, was observed to be the highest thermal conductivity. Phonon scattering processes were considered to analyze the thermal conductivity with the full Callaway model. The grain size and the concentration of the extended and the point defects were used as the fitting parameters. Microstructure of diamond films was investigated with the scanning electron microscopy and Raman spectroscopy.

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The Characteristics of Bonding for Thermo-plastic using Solar Energy (태양에너지를 이용한 열경화성 플라스틱 접합특성)

  • Kim, Ok-Sam;Kim, Il-Soo;Son, Joon-Sik;Seo, Joo-Hwan;Moon, Chae-Joo
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.2
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    • pp.106-111
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    • 2007
  • In this research work attempts were made to study the bonding of thermo-plastics with adhesives using solar radiation. In order to study the curing behaviour necessary experiments were conducted under varying conditions of temperature, exposure time and power of solar energy. The cured samples were then studied under the optical microscope before subjecting to tensile testing in order to study their mechanical properties of thermo-plastics. The fracture surfaces were further studied under the Scanning Electron Microscopy(SEM) in order to research the microstructural changes that are taken place during curing. In order to measure the performance of solar energy cured joints the parameters such as; bond strength, surface morphology, the microstructual changes, variation in properties of adhesives bonded joints are compared to that of specimen cured at ambient conditions and specimen cured using microwave techniques.

Electromagnetic Interference Reflectivity of Nanostructured Manganese Ferrite Reinforced Polypyrrole Composites

  • Chakraborty, Himel;Chabri, Sumit;Bhowmik, Nandagopal
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.6
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    • pp.295-298
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    • 2013
  • Nano-size manganese ferrite reinforced conductive polypyrrole composites reveal a core-shell structure by in situ polymerization, in the presence of dodecyl benzene sulfonic acid as the surfactant and dopant, and iron chloride as the oxidant. The structure and magnetic properties of manganese ferrite nano-fillers were measured, by using X-ray diffraction and vibrating sample magnetometer. The morphology, microstructure, and conductivity of the composite were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and four-wire technique. The microwave-absorbing properties of composites reinforcement dispersed in resin coating with the coating thickness of 1.2 nm were investigated, by using vector network analyzers, in the frequency range of 8~12 GHz. A reflection loss of -8 dB was observed at 10.5 GHz.