Departamento de Ciencia e Ingeniería de los Materiales e Ingeniería Químicahttp://hdl.handle.net/10016/141262017-07-23T20:49:21Z2017-07-23T20:49:21ZFunctional evolution of scalar fields in bounded one-dimensional regionsBarbero Gonzalez, Jesus FernandoMargalef Bentabol, JuanSánchez Villaseñor, Eduardo Jesúshttp://hdl.handle.net/10016/246972017-06-21T00:10:41Z2017-02-27T00:00:00ZFunctional evolution of scalar fields in bounded one-dimensional regions
Barbero Gonzalez, Jesus Fernando; Margalef Bentabol, Juan; Sánchez Villaseñor, Eduardo Jesús
We discuss the unitarity of the quantum evolution between arbitrary Cauchy surfaces of a 1 + 1 dimensional free scalar field defined on a bounded spatial region and subject to several types of boundary conditions including Dirichlet, Neumann and Robin.
2017-02-27T00:00:00ZChemical imaging of phase separated polymer blends by fluorescence microscopySerrano, BernaBaselga Llidó, JuanBravo, JulioMikes, FrantisekSesé, LEsteban, IPiérola, I. F.http://hdl.handle.net/10016/246112017-06-01T00:14:07Z2000-06-01T00:00:00ZChemical imaging of phase separated polymer blends by fluorescence microscopy
Serrano, Berna; Baselga Llidó, Juan; Bravo, Julio; Mikes, Frantisek; Sesé, L; Esteban, I; Piérola, I. F.
Blends of poly(vinylacetate) (PVAc) and poly(cyclohexylmethacrylate) (PCHMA) labeled by copolymerization
with 4-methacryloylamine-48-nitrostilbene (Sb), with (1-pyrenylmethyl)methacrylate
(Py), or with 3-(methacryloylamine)propyl-N-carbazole (Cbz) were prepared by casting dilute solutions
in tetrahydrofurane (THF) or chloroform. Films about 10 mm thick were formed. Phase
separation in two types of domains is observed by transmission optical microscopy (TOM) and
epifluorescence microscopy (EFM): small craters of 1 to 10 mm placed at the polymer–air interface
and larger domains, on the scale of 100 mm. The morphology of samples depends on the composition
of the polymer blend and on solvent. The green fluorescence of Sb, the violet of Py, or the blue
of Cbz provides imaging of the distribution of PCHMA in the different domains and in the matrix.
It is thus observed that (i) superficial craters and large domains are formed mainly by PCHMA and
(ii) the matrix is composed of PVAc in films cast from THF and it is a blend of the two polymers,
homogeneous at the submicrometric scale, for chloroform. The emission intensity of Py, recorded
by microfluorescence spectroscopy (MFS), yields a mapping similar to imaging detection. It is
remarkable that in films cast from chloroform, the smaller domains are distributed with a 2D
hexatic order disrupted by dislocations and disclinations, whereas in films cast from THF, a larger
heterogeneity is found, denoting different mechanisms of solvent evaporation.
2000-06-01T00:00:00ZEffect of crosslinker on swelling and thermodynamic properties of polyacrylamide gelsBaselga Llidó, JuanLlorente, M. A.Hernández-Fuentes, I.Masegosa, R.Mhttp://hdl.handle.net/10016/246092017-06-01T00:14:05Z1989-01-01T00:00:00ZEffect of crosslinker on swelling and thermodynamic properties of polyacrylamide gels
Baselga Llidó, Juan; Llorente, M. A.; Hernández-Fuentes, I.; Masegosa, R.M
PAA networks have been prepared by crosslinking copolymerization of acry- lamide (AA) and N,N'-methylen-bis-acrylamide (BA) in water. The degree of swelling was measured in the range v2 =0-0.16 as a function of crosslinker proportion, C (%w/w) and total concentration, Cr (g/ 100 ml). The swelling of two networks with BA contents of 3 ,;; and 10% were measured as a function of temperature in the range 10-30°C. The interpretation of elastic and swelling data in terms of the scaling law lfh I =Av 2m, shows a transition from a good solvent regime
to a collapsed state for the polymer chains, when the crosslinker proportion is around 5 to 7%. Results of elastic and swelling measurements were used to determine the x parameter. A different
dependence of x with v2 was found for gels with BA contents below and above 5-7%. The enthalpic contribution to the interaction parameter XH was calculated from swelling experiments as
a function of temperature. The results show that when the BA proportion is increased, the enthalpic
1989-01-01T00:00:00ZBivariate generating functions for a class of linear recurrences: General structureBarbero G., J. FernandoSalas Martínez, JesúsSánchez Villaseñor, Eduardo Jesúshttp://hdl.handle.net/10016/245962017-05-23T00:10:30Z2014-07-01T00:00:00ZBivariate generating functions for a class of linear recurrences: General structure
Barbero G., J. Fernando; Salas Martínez, Jesús; Sánchez Villaseñor, Eduardo Jesús
We consider Problem 6.94 posed in the book Concrete Mathematics by Graham, Knuth, and Patashnik, and solve it by using bivariate exponential generating functions. The family of recurrence relations considered in the problem contains many cases of combinatorial interest for particular choices of the six parameters that define it. We give a complete classification of the partial differential equations satisfied by the exponential generating functions, and solve them in all cases. We also show that the recurrence relations defining the combinatorial numbers appearing in this problem display an interesting degeneracy that we study in detail. Finally, we obtain for all cases the corresponding univariate row generating polynomials.
2014-07-01T00:00:00Z