Quasiparticle conductivities in disordered d-wave superconductors

We study the quasiparticle transport coefficients in disordered d-wave superconductors. We find that spin and charge excitations are generally localized unless magnetic impurities are present. If the system is close to a nesting point in the impurity-scattering unitary limit, the tendency towards localization is reduced while the quasiparticle density of states gets enhanced by disorder. We also show that the residual repulsive interaction among quasiparticles has a delocalizing effect and increases the density of states.     

(+)-syn-Benzotriborneol: the first functionalised enantiopure C3-symmetric benzocyclotrimer

Copper(I) thiophencarboxylate readily and effectively cyclotrimerises protected 5-bromo-6-trimethylstannylborn-5-en-2-ols, leading to oxygen-functionalised benzocyclotrimers. The remarkably high syn to anti ratio is driven by relative displacement of the halide and metal on the alkene moiety and depends on the steric hindrance of the protecting group of the hydroxy function. The less hindered methyl derivative affords exclusively syn-benzocyclotrimer. The readily removable methoxymethyl derivative gives enantiopure syn-tribenzoborneol in high yields.     

Multiple functional group cooperation in phosphate diester cleavage promoted by Zn(II) complexes

Zn(II) complexes bearing multiple auxiliary organic groups greatly accelerate the cleavage of a phosphate diester.     

Procedure for retrieving the optical properties of a two-layered medium from time-resolved reflectance measurements

A procedure for retrieving the optical properties of a two-layered diffusive medium based on an exact analytical solution of the diffusion equation and on relative multidistance time-resolved reflectance measurements is presented. The method overcomes some limitations of previously developed procedures. Five parameters of the medium have been fitted: the absorption and the reduced scattering coefficients of both layers and the thickness of the first layer. The actual values of the parameters are correctly retrieved by the procedure. The inversion procedure does not require an initial guess for the unknown optical properties, but the starting value for the thickness of the first layer needs to be estimated with an error smaller than 50%.     

Secondary ion mass spectrometry and X-ray photoelectron spectroscopy investigation on chemical vapor deposited CeO(2-)ZrO(2)-TiO(2) thin films

Mixed CeO(2)-ZrO(2) systems have attracted widespread interest for their use in three-way catalyst (TWC) technology for automotive exhaust conversion to non-toxic products. In this work, CeO(2)-ZrO(2) thin films were deposited, via chemical vapor deposition, in order to obtain nanoscale materials with a high surface-to-volume ratio, with precise control of system properties. The addition of TiO(2) as buffer layer was also investigated. Cordierite was chosen as substrate, being the usual refractory material for catalytic mufflers. The multilayers were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). In particular, the combination of SIMS and XPS allowed us to investigate both surface and in-depth chemical composition, studying also film-intermixing phenomena induced by annealing processes.     

Global theory for thermodynamic behaviour of a continuous medium

Summary A global theory for the thermodynamic behaviour of a material is introduced on the based of the Systems Theory. Hence the hypotheses for which a local formulation is deducible are specified.

---

Riassunto Partendo da una teoria globale del comportamento termodinamico di un materiale, espresso in termini della Teoria dei Sistemi, si precisano le ipotesi per le quali è possibile pervenire ad una formulazione locale.

     

Direct transition between a singlet Mott insulator and a superconductor

We argue that a normal Fermi liquid and a singlet, spin-gapped Mott insulator cannot be continuously connected, and that some intermediate phase must intrude between them. By explicitly working out a case study where the singlet insulator is stabilized by orbital degeneracy and an inverted Hund's rule coupling, mimicking a Jahn-Teller effect, we find that the intermediate phase is a superconductor.     

Entropy equation and absolute temperature

In this paper we consider the equivalence between the heat and the entropy balance laws. These two equations are related by an integrating factor, which defines the absolute temperature. This result is obtained applying the thermodynamic laws to a perfect fluid. So that, by means of the entropy equation we introduce the Second Law of Thermodynamics. Two particular cases of constitutive equations, both for the internal energy and for the heat flux, are considered and their corresponding differential equations, useful to study the behaviour of these materials, are also given.