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991.
J.L. Martínez‐Morales 《Annalen der Physik》2006,15(9):653-662
Properties of the eigentensors of the Lichnerowicz Laplacian for the Euclidean Schwarzschild metric are discussed together with possible applications to the linear stability of higher‐dimensional instantons. The main statement of the article is that any eigentensor of the Lichnerowicz operator in a Euclidean (possibly higher‐dimensional) Schwarzschild metric is essentially singular at infinity. 相似文献
992.
Polypropylene matrix composites, with different degrees of reinforcement with long glass fibres, are employed in different fields of the industry, such as aeronautics or automotive. Samples of the material were exposed to artificial accelerated photo-ageing in UV chamber (Heraeus Xenotest 150S). Their high content of glass fibres causes a surface degradation that can seriously affect mechanical properties. Therefore, dynamic mechanical and tensile tests were carried out in order to compare the changes of the properties with exposure time. These modifications are accompanied with microscopic changes in the crystallinity as can be seen in the thermal analysis experiments. 相似文献
993.
We extend the Gustavsson–Peetre method to the context of N ‐tuples of Banach spaces. We give estimates for the norm of the interpolated operator. The method is applied to tuples of weighted L p ‐spaces and to tuples of Orlicz spaces identifying the outcoming spaces in both cases. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
994.
R. Ortega D. d'Enterria G. Martınez D. Baiborodin H. Delagrange J. Dıaz F. Fernández H. Löhner T. Matulewicz R. W. Ostendorf S. Schadmand Y. Schutz P. Tlusty R. Turrisi V. Wagner H. W. Wilschut N. Yahlali 《The European Physical Journal A - Hadrons and Nuclei》2006,28(2):161-171
Measured hard-photon multiplicities from second-chance nucleon-nucleon collisions are used in combination with a kinetic thermal
model to estimate the breakup times of excited nuclear systems produced in nucleus-nucleus reactions at intermediate energies.
The obtained nuclear breakup time for the 129Xe + natSn reaction at 50 A MeV is Δτ ≈ 100-300 fm/c for all reaction centralities. The lifetime of the radiating sources produced in seven other different heavy-ion reactions
studied by the TAPS experiment is consistent with Δτ ≈ 100 fm/c, such relatively long thermal photon emission times do not seemingly support the interpretation of nuclear breakup as due
to a fast spinodal process for the heavy nuclear systems studied. 相似文献
995.
Roberto Martínez Eduardo Corts R. Alfredo Toscano Irma Linzaga 《Journal of heterocyclic chemistry》1990,27(2):363-366
It has been reported that the reaction of β-naphthylamine, dimedone and the appropriate aromatic aldehyde in ethanol gave 1,2,3,4,5,6-hexahydro-2,2-dimethyl-5-aryl-6-aza-9,10-benzophenanthren-4-ones, III , which upon treatment with chromic anhydride, yielded the corresponding tetrahydro derivatives, IV . However, the attempted preparation of these compounds resulted instead of the formation of isomeric acridin-11-ones, V and VI . Structures were confirmed by ir, 1H nmr, ms and X-ray spectroscopy. 相似文献
996.
V. Devesa M. A. Súer V. W.‐M. Lai S. C. R. Granchinho J. M. Martínez D. Vlez W. R. Cullen R. Montoro 《应用有机金属化学》2002,16(3):123-132
The arsenic species present in samples of the crayfish Procambarus clarkii caught in the area affected by the toxic mine‐tailing spill at Aznalcóllar (Seville, Southern Spain) were analyzed. The total arsenic contents ranged between 1.2 and 8.5 µg g?1 dry mass (DM). With regard to the different species of arsenic, the highest concentrations were for inorganic arsenic (0.34–5.4 µg g?1 DM), whereas arsenobetaine, unlike the situation found in marine fish products, was not the major arsenic species (0.16 ± 0.09 µg g?1 DM). Smaller concentrations were found of arsenosugars 1a (0.18 ± 0.11 µg g?1 DM), 1b (0.077 ± 0.049 µg g?1 DM), 1c (0.080 ± 0.089 µg g?1 DM), and 1d (0.14 ± 0.13 µg g?1 DM). The presence of two unknown arsenic species was revealed (U1: 0.058 ± 0.058 µg g?1 DM; U2: 0.12 ± 0.12 µg g?1 DM). No significant differences were seen with respect to the total arsenic contents between the sexes. However, significant differences in the total arsenic contents were revealed between the area affected by the spill and the area not affected, the contents being greater in the affected area. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
997.
J. García A. Martínez F. Cuesta-soto P. Sanchis J. Blasco J. Martí 《Optical and Quantum Electronics》2005,37(1-3):199-211
Extremely large group velocity dispersion of both signs can be achieved at the band edges of guided modes in photonic crystal waveguides. The selection of a proper value and sign of this parameter allows the design of short-length waveguides to compensate for pulse broadening. This pulse broadening can be caused, for instance, when a photonic crystal delay line is introduced. We present a theoretical study of the possibilities of using photonic crystal waveguides as intra-circuital dispersion compensation elements for ultrashort pulses, so the width of a transmitted pulse can be reduced. However, we also demonstrate that recovering the original pulse shape is not possible for these large-bandwidth pulses due to higher-order dispersion terms. 相似文献
998.
999.
Fernando GIMENEZ Javier Orengo VALVERDE 《数学学报(英文版)》2007,23(7):1317-1326
On surfaces we give conditions under which the solution of a restricted local isoperimetric problem for sectors with small solid angle is the circular sector and we characterize these surfaces. Also we study this problem for general spherical cones on hypersurfaces in higher dimensional Riemannian manifolds. 相似文献
1000.
Z Pawlicová J R Albert-García I Sahuquillo Mateo J V García M Catalá Icardo J Martínez Calatayud 《Analytical sciences》2006,22(1):29-34
A new, robust and simple method is proposed for the chemiluminescent determination of the pesticide Bromoxynil. The empirical procedure is performed with the aid of a flow-injection manifold provided with an on-line photo-reactor to obtain chemiluminescent photofragments. After a period of 12 s of irradiation with an 8 W low-pressure mercury lamp, a chemiluminescent oxidation was performed with the system potassium permanganate in a polyphosphoric acid medium. The photolysis required a basic medium (KOH 0.014 mol l(-1)) with ethanol (1%) as a sensitizer. The method allowed the determination of 134 samples (h-1) of Bromoxynil in a wide interval of concentrations, over the range 5 x 10(-3) - 1 mg l(-1); the detection limit was 5 x 10(-3) mg l(-1). The RSD (n=24) at 0.25 mg l(-1) of the pesticide level was 2.3%. The method was applied to a water sample and to a formulation. 相似文献