Blocking sets in 3-designs

We characterize the existence of blocking sets in a particular class of S (3,4,v) and we give a construction to obtain S(3,4,2v) having blocking sets.Lavoro eseguito nell'ambito del GNSAGA e con contributo del M.P.I.     

On the integrable selections of certain multifunctions

The aim of this paper is to establish a result of which the following is a particular case: If F is a nonempty closed-valued measurable multifunction, from a nonatomic σ-finite measure space (T, F, μ) into a separable real Banach space E, such that $$d(0,F( \cdot )) \in L^1 (T) and \mathop {\lim }\limits_{\lambda \to + \infty } \frac{{d(\lambda x,F(t))}}{\lambda } = 0$$ for almost every t ∈ T and for every x ∈ E, then each closed hyperplane of L ¹(T,E) contains a selection of F. Also, some consequences are indicated.     

CH...O and CH...F links form the cage structure of dioxane-trifluoromethane

The molecular beam Fourier transform microwave spectrum of 1,4-dioxane-trifluoromethane has been assigned and measured. The two subunits form a cage stabilized by one C-H...O and two C-H...F weak hydrogen bonds. The C-H...O link involves the axial lone pair of one of the two equivalent ring oxygens, while the two C-H...F bridges connect trifluoromethane to the two axial hydrogens in positions 3 and 5. The dissociation energy has been estimated from the D(J) centrifugal distortion parameter to be approximately 6.8 kJ/mol.     

Openness properties of real multifunctions on some connected spaces

Real multifunctions on connected spaces are studied. In the class of connected and locally compact metrizable spaces structural characterizations are shown of such ones on which each either lower or upper semicontinuous real multifunction with connected values (and possibly with boundary point-inverses) is either almost open or pseudo-almost open. Many related results are obtained.     

Further Considerations on a Variational Property of Integral Functionals

In this note, we point out that the conclusion of Theorem 2.1 of Ref. 1 applies to any decomposable linear subspace of L ^p (T, E).     

Langmuir–Blodgett films of pyridinium-dicyanomethanide dyes mixtures with photobleachable absorption bands

We report on Langmuir-Blodgett (LB) films characterization of 4-[5-dicyanomethanido)thien-2-y1]-N-(n-hexadecyl)pyridinium (C₁₆H₃₃-PDCNT), and 1-(N-(n-hexadecy]-4-pyridinio)-2-[5-(dicyanomethanido)thien-2-yl]ethene (C₁₆H₃₃-PDCNTE); LB films of the pure compounds and of the mixtures of the two compounds were prepared at 291 K: UV-vis investigation revealed the presence of photobleachable absorption bands, the ones at about 530 nm and 640 nm were due to charge transfer transitions of the monomer of C16H33-PDCNT and C₁₆H₃₃-PDCNTE, respectively; the sharp, photobleachable ones shifted to shorter wavelengths were due to H-aggregates of the two compounds. By changing the molar ratios of the two compounds in the mixtures and in other cases by annealing the LB films, the absorption maxima of the sharp, photobleachable bands due to H-aggregates could be tuned in the range 415–467 nm. These LB films are thus very promising in view of optical data storage applications.