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361.
362.
Pavel Horváth František Schauer Ivo Kuřitka Ota Salyk Martin Weiter Norbert Dokoupil Stanislav Nešpůrek Vlastimil Fidler 《Monatshefte für Chemie / Chemical Monthly》2001,132(1):177-183
Summary. The photoluminescence of plasma-prepared polysilanes during the change from linear 1D Si chains to an amorphous 3D Si network
was studied. The excitonic absorption band with a maximum at 353 nm in 1D Si experiences a blue shift and broadening upon
introduction of branching and networking defects. With the gradual transition from 1D to 3D structure, an extensive redistribution
of oscillator intensity along the absorption edge, accompanied by a decrease of the resolution of the σ-σ* band, was observed. In the short wavelength region of the excitation spectra there is an enormous increase of excitonic emission
at 328 nm. This effect is tentatively attributed to the excitation of the phenyl group or to the phenyl-silicon bond as confirmed
by effusion spectra of the phenyl species.
Received July 10, 2000. Accepted (revised) September 8, 2000 相似文献
363.
Mayako Takahashi Hiromoto Watanabe Junko Kikkawa Masaki Ota Masaru Watanabe Yoshiyuki Sato Hiroshi Inomata Nobuyuki Sato 《Analytical sciences》2006,22(11):1441-1447
The extraction of carotenoids from Japanese persimmon peels by supercritical fluid extraction (SFE), of which the solvent was CO(2), was performed. In order to enhance the yield and selectivity of the extraction, some portion of ethanol (5 - 20 mol%) was added as an entrainer. The extraction temperature ranged from 313 to 353 K and the pressure was 30 MPa. The effect of temperature on the extraction yield of carotenoids was investigated at 10 mol% of the ethanol concentration in the extraction solvent, and a suitable temperature was found to be 333 K among the temperatures studied with respect to the carotenoid yield. With increasing the entrainer amount from 0 to 10 mol% at a constant temperature (333 K), the carotenoid yield in the extraction was improved, whereas the selectivity of the extracted carotenoids was drastically depressed. We also conducted qualitative and quantitative analyses for the carotenoid components in the extract by HPLC, and analyzed the extraction behavior of each individual carotenoid (alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein, and zeaxanthin). The selectivity of each carotenoid changed with the elapsed time and its time evolution was dependent on the carotenoid component, indicating that the location profile and the content can be important factors to understand the SFE behavior of each carotenoid in persimmon peels. 相似文献
364.
365.
F. Kokai K. Amano H. Ota F. Umemura 《Applied Physics A: Materials Science & Processing》1992,54(4):340-342
XeCl laser ablation of yttria stabilized zirconia (YSZ) in air and in vacuum (1.3×10–4 Pa) is studied by means of etch depth measurements, scanning electron microscopy, and X-ray photoelectron spectroscopy of ablated surfaces. Results on ablation rate, surface morphology, and surface chemical composition are discussed in terms of the influence of ambient atmosphere on the ablation process, rapid melting and solidification of ablated surfaces, and preferential removal of oxygen atoms from the YSZ surface. 相似文献
366.
367.
In order to evaluate the clinical application of the calcium absorption test from the intestine, the intestinal 47Ca absorption test by using a scintillation camera was carried out in our laboratory. The results in the intestinal 47Ca absorption test using a scintillation camera showed a good correlation to the results which were estimated by using an arm counter previously reported by us. The rate of intestinal 47Ca absorption in 8 healthy volunteers (5 male, 3 female, average age: 37.6 +/- 9.5 years) was 52.0 +/- 3.8%, 74.3% in a patient with primary hyperparathyroidism 30.4% and 32.7% in two patients with idiopathic hypoparathyroidism respectively. This method is more easily handled and can be performed for only 4 days in institutes that are set up with scintillation camera without any special preparations, and it is recommended to be of clinical usefulness for the diagnosis of calcium metabolic disorders. 相似文献
368.
The axial position of a laser-trapped particle has been controlled by modification of the wave front by means of a membrane deformable mirror. The mirror gives wave-front modulation in terms of Zernike polynomials. By modulation of the Zernike defocus term we can modulate the particle position under conditions of laser trapping. A polystyrene particle of 1-microm diameter was moved along the optical axis direction for a distance of 2370 nm in minimum steps of 55.4 nm. We also demonstrated particle oscillation along the optical axis by changing the focal position in a sinusoidal manner. From the frequency dependency of the amplitude of particle oscillation we determined the spring constant as 91.7 nN/m. 相似文献
369.
370.
Tokuhiro Watanabe Ikuko Ueda Naomi Hayakawa Yasuo Kondo Hiroko Adachi Akiko Iwasaki Shizuko Kawamata Fumiko Mentori Miyuki Ichikawa Kayo Yuasa Akihiro Ohta Teruo Kurihara Hiroshi Miyamae 《Journal of heterocyclic chemistry》1990,27(3):711-716
2,3-Dichloro- and 2,5-dichloropyrazines were treated with sodium azide. The former gave diazidopyrazines and the latter, monoazidomonochloropyrazines. Pyrolysis of 2,3-diazidopyrazines resulted the production of 1,2-dicyanoiminoethanes and that of 2-azido-5-chloropyrazines, chloroimidazoles. 相似文献