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181.
182.
Rafael Herná ndez Marí a J. Vá zquez-Gallo 《Transactions of the American Mathematical Society》2001,353(1):95-115
We determine the degree of some strata of singular cubic surfaces in the projective space . These strata are subvarieties of the parametrizing all cubic surfaces in . It is known what their dimension is and that they are irreducible. In 1986, D. F. Coray and I. Vainsencher computed the degree of the 4 strata consisting on cubic surfaces with a double line. To work out the case of isolated singularities we relate the problem with (stationary) multiple-point theory.
183.
Rafael de la Madrid 《International Journal of Theoretical Physics》2007,46(8):1986-1997
This paper is a contribution to the problem of particle localization in non-relativistic Quantum Mechanics. Our main results
will be (1) to formulate the problem of localization in terms of invariant subspaces of the Hilbert space, and (2) to show
that the rigged Hilbert space incorporates particle localization in a natural manner. 相似文献
184.
185.
Jesús del Barrio Eva Blasco Luis Oriol Rafael Alcalá Carlos Sánchez‐Somolinos 《Journal of polymer science. Part A, Polymer chemistry》2013,51(8):1716-1725
We have demonstrated the preparation of a series of photoaddressable supramolecular block copolymers by mixing a carboxy‐terminated azobenzene derivative, 6‐[4‐(4′‐cyanophenylazo)phenyloxy]hexanoic acid (AZO), and two polystyrene‐b‐poly(4‐vinylpiridine) (PS‐b‐P4VP) block copolymers. AZO can be selectively attached to the P4VP block of PS‐b‐P4VP through hydrogen bonding interactions. The assembly of AZO with vinylpyridine group‐containing polymers was initially investigated on a model system composed of P4VP homopolymer and AZO. Homogeneous liquid crystalline materials were obtained for ratios of AZO to vinylpyridine repeating unit, x, lower or equal to 0.50. Mixtures with higher x resulted in heterogeneous materials showing clear macrophase separation. Accordingly, a series of hydrogen‐bonded complexes of PS‐b‐P4VP and AZO, PS‐b‐P4VP(AZO)x, with x = 0.25 and x = 0.50 were prepared. Lamellar and spherical morphologies were observed for the complexes based on PS24‐b‐P4VP9.5 (Mn,PS = 24,000, Mn,P4VP = 9500) and PS24‐b‐P4VP1.9 (Mn,PS = 24,000, Mn,P4VP = 1900), respectively. Photoinduced orientation of the azobenzene units was obtained in films of P4VP(AZO)x and PS‐b‐P4VP(AZO)x with x = 0.25 and 0.50 by using 488 nm linearly polarized light and characterized through birefringence and dichroism measurements. This investigation shows a versatile and less laborious approach to azobenzene‐containing polymer materials with low chromophore content, of interest in optical application. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
186.
By means of a local integral formula on a maximal surface, which involves the hyperbolic angle between the unit normal vector
field and a fixed timelike direction, we give a new proof of the parametric Calabi-Bernstein theorem. A suitable modification
of the integral formula gives an independent proof to the non-parametric case of this result. 相似文献
187.
Antonia María Rojano‐Delgado José Ruiz‐Jiménez María Dolores Luque de Castro Rafael De Prado 《Electrophoresis》2010,31(8):1423-1430
A simple CE method for simultaneous determination of glyphosate and its metabolites (i.e. aminomethylphosphonic acid, glyoxylate, sarcosine and formaldehyde) in plants is reported here. A BGE of pH 7.5, 10% ACN, 7.5 mM phthalate, containing 0.75 mM hexadecyltrimethylammonium bromide as an electro‐osmotic flow modifier, an applied voltage of –20 kV and absorptiometric monitoring at 220 nm were the optimal chemical and instrumental parameters. The method, with development time 20 min, shows linear calibrations within the range 5–500 μg/mL (for all target analytes) with correlation coefficients between 0.999 and 0.998. It has been validated by application to samples of Lolium spp. The electroinjection mode hinders most interferents to enter the capillary, thus providing a clean electropherogram and making unnecessary long sample‐preparation steps. 相似文献
188.
A warm standby n-system with operational and repair times following phase-type distributions is considered. The online unit goes through degradating levels, determined by inspections. Two types of repairs are performed, preventive and corrective, depending on the degradation level. The standby units undergo corrective repair. This systems is governed by a level-dependent-quasi-birth-and-death proces (LDQBD process), whose generator is constructed. The availability, rate of occurrence of failures, and other quantities of interest are calculated. A numerical example including an optimization problem and illustrating the calculations is presented. This system extend other previously studied in the literature. 相似文献
189.
We present a study of the Gaussian q-measure introduced by Díaz and Teruel from a probabilistic and from a combinatorial viewpoint. A main motivation for the introduction of the Gaussian q-measure is that its moments are exactly the q-analogues of the double factorial numbers. We show that the Gaussian q-measure interpolates between the uniform measure on the interval [−1,1] and the Gaussian measure on the real line. 相似文献
190.