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991.
A. E. S. Vives S. Moreira S. M. B. Brienza O. L. A. Zucchi V. F. Nascimento Filho 《Journal of Radioanalytical and Nuclear Chemistry》2006,270(1):147-153
Summary The objective of this study was to use synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF) for the
determination of metals and other elements in food available to the population in commercial establishments, in order to evaluate
the risks of contamination by these products. The analyzed species were vegetables, leafy vegetables, fruits, cereal and grain.
The results indicated that some species were contaminated by Cr, Cu, Zn and Pb with concentrations much higher than the reference
values. 相似文献
992.
The influence of resonances on the muon transfer processes from muonic hydrogen to oxygen and neon (pμ)1s + O8+ → p + (μO)nl7+ and (pμ)1s + Ne10+ → p + (μNe)nl9+ is considered using the Smith lifetime matrix formalism. It is shown that the existence of a long lived resonance in the
case of Ne induces a stronger dependence on collision energy of the muon transfer cross-section for this system.
Present address: Chemistry Department, Vancouver University, Vancouver, BC V6T 1Z3, Canada 相似文献
993.
R. Lü H. Pan J.-L. Zhu B.-L. Gu 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,26(4):479-491
The tunneling of a giant spin at excited levels is studied theoretically in mesoscopic magnets with a magnetic field at an
arbitrary angle in the easy plane. Different structures of the tunneling barriers can be generated by the magnetocrystalline
anisotropy, the magnitude and the orientation of the field. By calculating the nonvacuum instanton solution explicitly, we
obtain the tunnel splittings and the tunneling rates for different angle ranges of the external magnetic field ( θ
H = π/2 and π/2 < θ
H < π). The temperature dependences of the decay rates are clearly shown for each case. It is found that the tunneling rate
and the crossover temperature depend on the orientation of the external magnetic field. This feature can be tested with the
use of existing experimental techniques.
Received 12 March 2001 and Received in final form 18 October 2001 相似文献
994.
The aim of this article is to give a new dynamical proof of the Ferrand–Obata theorem when the manifold is compact. This will give us a generalisation of this theorem to transversally conformal foliations ofcodimension greater than three and constant basic functions. 相似文献
995.
996.
T. Riesterer J. G. Bednorz K. A. Müller B. Reihl 《Applied Physics A: Materials Science & Processing》1987,44(1):81-82
We have measured ultraviolet and inverse-photoemission spectra of the novel superconductor Sr02La1.8CuO4. Our results compare favorably with recent band-structure calculations for La2CuO4.A full account of this work will be published elsewhere [1] 相似文献
997.
Bruno Després 《Comptes Rendus Mathematique》2006,342(1):73-78
We describe a Weak Rankine Hugoniot relation for constrained discontinuous solutions of conservation laws. The constraint is convex in the primitive variable. Various examples show the potential interest of this approach. To cite this article: B. Després, C. R. Acad. Sci. Paris, Ser. I 342 (2006). 相似文献
998.
T. Gühne V. Gottschalch G. Leibiger H. Herrnberger J. Kovác J. Kovác Jr. R. Schmidt-Grund B. Rheinländer D. Pudis 《Laser Physics》2006,16(3):441-446
In this paper, we report on the design and optical properties of laser diodes with an emission wave-length of ~1170 nm based on an (InGa)As/GaAs double quantum well active layer. The back and front facet of the laser diodes were coated with SiOx dielectric films that influence the output optical power by enhancing or lowering the facet reflectivity. The measurements show improvement of the facet-coated laser diode properties in the threshold-current-density reduction along with light output power enhancement. Furthermore, a narrow far field pattern and high side mode suppression have been observed. 相似文献
999.
Jindun Liu A. J. B. Kemperman G. H. Koops M. Wessling 《中国颗粒学报》2006,4(2):98-102
A novel method of fabricating composite mosaic membranes was studied on the basis of interracial polymerization (IP) by coating a thin selective layer onto the surface of a micro-porous hollow-fiber membrane, in which, 2,5-diaminobenzene sulfonic acid was used as one monomer of the IP reaction, and a mixture of trimesoyl chloride (TMCI) and 4-(chloromethyl) benzoyl chloride as the other monomer. Through the IP reaction a thin selective layer with negatively charged groups could be first formed on the polyethersulfone (PES) support membrane. Then trimethylamine solution was introduced to modify the IP layer through a quaternization reaction. Thus the selective layer of this composite membrane contained both negatively charged and positively charged groups to perform the mosaic functionality. Characterization of the composite mosaic membranes was carried out through permeation experiments using different inorganic salts and dyes. The experimental results showed that the membranes could permeate both mono- and bi-valent inorganic salts, but reject larger organic molecules. Such a mosaic membrane is potentially useful for the separation of salts from water-soluble organics, especially in dye and textile industries. 相似文献
1000.
L.B.Magalas 《物理学进展》2006,26(3):258-276
本文广泛地收集了有关内耗,力学谱,超声衰减方面的专著及会议文集。反映了20世纪在此领域的英文,俄文出版的书籍。也列出了历次国际会议及前苏联,乌克兰,中国的国内会议。文中包括了点缺陷,电,声子,位错,晶界,电畴等诸方面在内的内耗与力学谱工作。 相似文献