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Tri-n-butyl phosphate (TBP) is used to extract tungsten(IV) from 0.5 M hydrochloric acid containing molybdenum(VI) and other metals. Tungsten(VI) in the TBP solution is reduced by tin(II) chloride and n-butyl acetate is used for dilution. The tungsten blue formed in the TBP/n-butyl acetate medium (1:1) is measured at 615 nm. The apparent molar absorptivity is about 1000 1 mol?1 cm?1; calibration graphs are linear in the range 0.1–1.5 mg of tungsten. 相似文献
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Takashi Sasaki Nobutaka Yamauchi Satoshi Irie Kensuke Sakurai 《Journal of Polymer Science.Polymer Physics》2005,43(2):115-124
Glass transition, cold crystallization, and melting of freeze‐dried poly(L‐lactide) (PLLA) prepared from dilute 1,4‐dioxane solutions were investigated by differential scanning calorimetry (DSC). Conventional DSC measurements of heating scans revealed that freeze‐dried PLLA prepared from a 0.07 wt % solution undergoes a two‐step cold crystallization (or reorganization) with a lower exotherm appearing at about 78 °C and with a higher broad exotherm between 110–155 °C. The peak temperature of the former exotherm is about 50 K lower than that observed for a reference bulk sample. Step‐scan mode DSC, which provides information essentially equivalent to that obtained from the temperature‐modulated DSC, revealed that the glass‐transition temperature is about 6 K lower than that of the reference bulk. These findings suggest enhanced chain mobility for freeze‐dried PLLA. Freeze‐dried PLLA that crystallized at 80 °C for 40 min was revealed to contain a rather large amount of rigid amorphous material (42%). © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 115–124, 2005 相似文献
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Remodeling of gp41-C34 peptide leads to highly effective inhibitors of the fusion of HIV-1 with target cells 总被引:7,自引:0,他引:7
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Nobutaka Ito 《Journal of Terramechanics》1987,24(4):251-261
A practical method of reducing the resistance of a tracked vehicle to turning or steering motion is discussed. The torque of the sprocket shaft for driving the crawler was measured and used to evaluate how the resistance varied compared with the existing method to turning. There are two ways of reducing the turning resistance by decreasing the contact area of track; one is to decrease the width of the braked track and the other is to shorten its contact length during turning or steering motion. The former is practically impossible to control, but the latter is comparatively easy to do, even under that condition. Applying this mechanism, the resistant force (evaluated by measuring the driving torque of the sprocket shaft) could be reduced about 20% when the contact length of the braked track was shortened to form a small pivot area at its center. It was also reduced more than 50% when the contact length of both tracks was shortened to a pivot during turning motion. 相似文献
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Masaaki Hori Mariko Yoshida Kazumasa Yokoyama Koji Kamagata Fumitaka Kumagai Issei Fukunaga Kouhei Kamiya Michimasa Suzuki Yoshitaka Masutani Nozomi Hamasaki Yuriko Suzuki Shinsuke Kyogoku Nobutaka Hattori Shigeki Aoki 《Magnetic resonance imaging》2014