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Optical characterization of sol gel TiO<Subscript>2</Subscript> monoliths doped with Brilliant Green
S. A. Tomás O. Zelaya R. Palomino R. Lozada O. García J. M. Yáñez A. Ferreira da Silva 《The European physical journal. Special topics》2008,153(1):255-258
Amorphous titanium dioxide monoliths doped with brilliant green (BG) were synthesized by the sol-gel process. The optical
properties of the monoliths were characterized by Photoacoustic Spectroscopy and Photoluminescence Spectroscopy. The absorption
spectra for the BG-doped TiO2 monoliths exhibited two well defined absorption regions: a band below 400 nm corresponding to TiO2 absorption and three absorption bands centered at 424 nm, 588 nm, and 632 nm due to brilliant green. While the undoped TiO2 monoliths showed no luminescence, the doped samples showed a strong luminescence band at 673 nm, which increased its intensity
for increasing organic dye doping. 相似文献
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Stephen E. Rose Stephen J. Wilson Fernando O. Zelaya Stuart Crozier David M. Doddrell 《Magnetic resonance imaging》1994,12(8):1183-1190
A method that incorporates cardiorespiratory-gated 2DFT spin-echo imaging with blood flow enhancement suppression is described which enables high resolution microimaging of the rodent heart. This methodology was applied to obtain in vivo cardiac mouse and rat images with in-plane resolutions of 100–200 μm using high field vertical bore magnet systems. Suppression of intraventricular blood flow enhancement was achieved using a combined spin-echo/gradient-refocussed sequence to dephase magnetization from flowing spins prior to imaging. 相似文献
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Murphy K Harris AD Diukova A Evans CJ Lythgoe DJ Zelaya F Wise RG 《Magnetic resonance imaging》2011,29(10):1382-1389
Pulsed arterial spin labeling (PASL) is an increasingly common technique for noninvasively measuring cerebral blood flow (CBF) and has previously been shown to have good repeatability. It is likely to find a place in clinical trials and in particular the investigation of pharmaceutical agents active in the central nervous system. We aimed to estimate the sample sizes necessary to detect regional changes in CBF in common types of clinical trial design including (a) between groups, (b) a two-period crossover and (3) within-session single dosing. Whole brain CBF data were acquired at 3 T in two independent groups of healthy volunteers at rest; one of the groups underwent a repeat scan. Using these data, we were able to estimate between-groups, between-session and within-session variability along with regional mean estimates of CBF. We assessed the number of PASL tag-control image pairs that was needed to provide stable regional estimates of CBF and variability of regional CBF across groups. Forty tag-control image pairs, which take approximately 3 min to acquire using a single inversion label delay time, were adequate for providing stable CBF estimates at the group level. Power calculations based on the variance estimates of regional CBF measurements suggest that comparatively small cohorts are adequate. For example, detecting a 15% change in CBF, depending on the region of interest, requires from 7-15 subjects per group in a crossover design, 6-10 subjects in a within-session design and 20-41 subjects in a between-groups design. Such sample sizes make feasible the use of such CBF measurements in clinical trials of drugs. 相似文献
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CM Silva MF Duarte ML Mira MH Florêncio K Versluis AJ Heck 《Rapid communications in mass spectrometry : RCM》1999,13(12):1098-1103
Fast atom bombardment, combined with high-energy collision-induced tandem mass spectrometry, has been used to investigate gas-phase metal-ion interactions with captopril, enalaprilat and lisinopril, all angiotensin-converting enzyme inhibitors.Suggestions for the location of metal-binding sites are presented. For captopril, metal binding occurs most likely at both the sulphur and the nitrogen atom. For enalaprilat and lisinopril, binding preferably occurs at the amine nitrogen. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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Cubic CdS (β‐CdS) polycrystalline thin films were prepared on glass substrates by chemical synthesis at 80 °C. Samples were subjected to thermal treatments (TT) in the range of temperatures (T) 180 – 500 °C during 30 hours in different ambients. Annealing in air and in H2 produces in CdS larger lattice parameter enlargements (≤2.5 %) when T of TT increases up to T ≤ 500 °C. Whereas, annealing in Ar + S2 and vacuum provokes intermediate (≤1.2 %) and smaller (≤0.9 %) maxima values of the lattice parameter increments, respectively. Energy band gap (Eg) as a function of T of TT and as a function of the lattice parameter has been also studied where it was observed that Eg behaves in very different manners depending on the ambient chosen for annealing. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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M.E. de Anda ReyesG. Torres Delgado R. Castanedo Pérez J. Márquez MarínO. Zelaya Ángel 《Journal of photochemistry and photobiology. A, Chemistry》2012,228(1):22-27
In the preparation of CdO + CdTiO3 polycrystalline thin films by the sol-gel method, the optical, structural and crystalline properties, as well as the photocatalytic activity (PA) depends strongly on the sintering temperature (Ts) of the films and of the Ti/Cd ratio used in the precursor solution. In this work, CdO + CdTiO3 thin films were prepared using a Ti/Cd constant ratio in the precursor solution. The films were sintered at six different Ts in the 450-550 °C range, in an open atmosphere. The structure of the films was characterized by X-ray diffraction and the PA was evaluated by the photobleaching of methylene blue in an aqueous solution using a UV-vis spectrometer. The relative intensity of the diffraction peaks associated with CdO and CdTiO3, change with the Ts. The better photocatalytic activities were obtained for the films sintered at 490 °C and 550 °C. When the CdO was removed from the films by chemical etching the PA decreased, showing the importance of coupling both oxides. 相似文献