• Title/Summary/Keyword: Near-Field Microwave Microprobe (NFMM)

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Concentration of Sodium Chloride Solutions Sensing by Using a Near-Field Microwave Microprobe (비접촉 근접장 마이크로파 현미경을 이용한 NaCl 용액의 농도 측정)

  • Kim, Song-Hui;Yoon, Young-Woon;Babajanyan, Arsen;Kim, Jong-Chul;Lee, Kie-Jin
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.1
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    • pp.23-30
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    • 2007
  • We observed the NaCl concentration of solutions using a near-field microwave microprobe(NFMM). Instead of the usual technique, we take advantage of the noncontact evaluation capabilities of a NFMM. A NFMM with a high Q dielectric resonator allows observation of small variations of the permittivity due to changes in the NaCl concentration. The changes of NaCl concentration due to a change of permittivity of the NaCl solution were investigated by measuring the microwave reflection coefficient $S_{11}$ of the resonator. The NaCl sensor consisted of a dielectric resonator coupled to a probe tip at an operating frequency of about f=4 GHz. The change of the NaCl concentration is directly related to the change of the reflection coefficient due to a near field electromagnetic interaction between the probe tip and the NaCl solution. In order to determine the probe selectivity, we measured a mixture solution of NaCl and glucose.

열처리 조건에 따른 Rubrene 박막의 결정 특성 변화 연구

  • Yun, Yeong-Un;Kim, Song-Hui;Lee, Han-Ju;Kim, Tae-Dong;Lee, Gi-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.124-124
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    • 2009
  • We observed the changes of crystal structure of Rubrene (5,6,11,12-tetraphenylnaphthacene) polycrystal thin films at various in situ substrate temperature and process by scanning electron microscope(SEM), x-ray diffraction (XRD) and near-field microwave microprobe (NFMM). Amorphous rubrene thin film was initially obtained on 200 nm thick $SiO_2/Si$ substrate at 35 $^{\circ}C$ in a vacuum evaporation but in situ long time postannealing at the temperature 80 $^{\circ}C$ transformed the amorphous phase into crystalline. Four heating conditions are followed : (a) preheating (b) annealing (c) preheating, annealing (d) preheating, cooling(35 $^{\circ}C$), annealing. We have obtained the largest polycrystal disk in sample (c). But the highest crytallity and conductivity of the rubrene thin films were obtained in sample (d).

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