• Title/Summary/Keyword: 이중광자흡수계수

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Investigation on Femtosecond Laser Processing of Polymeric Thin Films (펨토초 레이저를 이용한 폴리머 박막 재료 초미세 공정에 관한 연구)

  • Jeoung S.C.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.669-670
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    • 2006
  • Two-photon absorption coefficient of a series of dyes in polymer thin films was determined by measuring the femtosecond laser ablation threshold. The threshold value of polymeric thin films decreased gradually when the dopant increased. The two-photon absorption coefficient of the dye molecules dispersed in the polymer film was estimated by using the theoretical relationship between the ablation threshold of the blended polymeric thin films and the dye concentration. The relative values of two-photon absorption cross-section are in good agreement with those measured in solution. On the other hand, the absolute values are smaller than the latter.

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Comparative Analysis of Bone Mineral Contents with Dual-Energy Quantitative Computed Tomography (이중에너지광자선의 전산화단층촬영술을 이용한 정량적 골무기물함량의 비교분석)

  • Choi, Tae-Jin;Yoon, Seon-Min;Kim, Ok-Bae;Lee, Sung-Moon;Suh, Soo-Jhi
    • Radiation Oncology Journal
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    • v.15 no.2
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    • pp.153-158
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    • 1997
  • Purpose : The Dual-Energy Quantitative Computed Tomography(DEQCT) was compared with bone equivalent $K_2HPO_4$ standard solution and ash weight of animal cadaveric trabecular bone in the measurement of bone mineral contents(BMC). Method and Materials : The attenuation coefficient of tissues highly depends on the radiation energy density and effective atomic number of composition, The bone mineral content of DEQCT in this experiments was determined from empirical constants and mass attenuation coefficients of bone,fat and soft tissue equivalent solution in two photon spectra. In this experiments, the BMC of DEQCT with 80 and $120kV_p$ X rays was compared to ash weight of animal trabecular bone. Results : We obtained the mass attenuation coefficient of 0.2409 0.5608 and 0.2206 in $80kV_p$, and 0.2046, 0.3273 and $0.1971cm^2/g$ in $120kV_p$ X-ray spectra for water bone and fat equivalent materials, respectively. The BMC with DEQCT was acomplished with empirical constants $K_1=0.3232,\;K_2$=0.2450 and mass attenuation coefficients has very closed to ash weight of animal trabecular bone The BMC of empirical DEQCT and that of manufacturing DEQCT were correlated with ash weight as a correlation r= 0.998 and r= 0.996, respectively. Conclusion : The BMC of empirical DEQCT using the experimental mass attenuation coefficients and that of manufacture have showed very close to ash weight of animal trabecular bone.

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