著者

Yoshihiro NAKAMURA Koji U. TAKAHASHI Jun HOSOI Hidetoshi HARA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.117, no.1, pp.220316, 2022 (Released:2022-08-09)

参考文献数

32

被引用文献数

1

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A new type of compact deep–UV micro–Raman spectroscopy system was developed with a single monochromator, front–illuminated cooled charge–coupled device, and 266 nm nanosecond pulsed laser to overcome laser–induced fluorescence from surrounding minerals and organic material. Deep–UV micro–Raman spectroscopy is particularly useful in analyzing the fluorescence–free Raman spectra of dispersed low–maturity carbonaceous material and coal, although deep–UV excitation lasers may cause serious degradation and laser–induced heating of the sample surface, especially in microanalysis. The laser–induced damage threshold for fully ordered graphite and coal (VRr = ~ 0.5%) was assessed to facilitate the acquisition of accurate Raman spectra with a spot size of ~ 1 µm. For fully ordered graphite, there was no serious degradation of the sample surface with an energy fluence of 0.10–2.50 J cm−2. Some sample surfaces became black at higher fluences of 1.96–2.50 J cm−2, suggesting irreversible damage by deep–UV lasers. The Raman shift of the G band after measurement involves a downshift of 1.7–7.4 cm−1 relative to other spectra obtained at low laser fluences of <0.34 J cm−2. The G band full width at half maximum (FWHM) also increased with increasing laser fluence. Serious degradation of polished coal surfaces occurs at even lower laser fluences of 0.34–2.50 J cm−2. The degree of change in Raman parameters such as the D and G band FWHM depends on the laser fluence during measurements. Heating and damage by a deep–UV laser is greater than that by visible lasers. Laser fluences of <0.16 and 0.34 J cm−2 are required for accurate Raman analyses of dispersed carbonaceous material in sedimentary rocks and fully ordered graphite in metasediment, respectively.

著者

Noboru TAKAMURA Yoshihiro NAKAMURA Katsu ISHIGAKI Jitsuro ISHIGAKI Mariko MINE Kiyoshi AOYAGI Shunichi YAMASHITA

出版者

Journal of Radiation Research Editorial Committee

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.45, no.2, pp.201-204, 2004 (Released:2004-08-10)

参考文献数

16

被引用文献数

11

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We examined the effect of stable iodine on thyroid gland blockade in patients with hyperthyroidism in order to make a preliminary evaluation of the appropriate dose of iodine prophylaxis in the event of a radiation emergency in Japan in which radioiodine is released to the environment. Eight patients were orally given single doses of 50 mg or 100 mg of potassium iodide, which contained 38 mg and 76 mg of iodide, respectively. Both doses significantly suppressed a thyroid uptake of 123I for 24 h (p = 0.03). The protective effects at 24 h were 73.3% and 79.5%, respectively. No side effects were observed during the trial. The present study demonstrates that a single oral administration of 38 mg of iodide produces a thyroid-blocking effect equivalent to that of 76 mg of iodide, suggesting that a reevaluation of the stable iodine dosage during radiation emergencies in iodine-rich areas such as Japan is warranted.