The Chiral Condensate of Strongly Coupled QCD in the 't Hooft Limit

Using the recently proposed generalization to an arbitrary number of colors of the strong coupling approach to lattice gauge theories\cite{Grignani:2003uv}, we compute the chiral condensate of massless QCD in the 't Hooft limit.Comment: 12 pages, revtex

Solvent-Free Synthetic Route for Cerium(IV) Metal–Organic Frameworks with UiO-66 Architecture and Their Photocatalytic Applications

A near solvent-free synthetic route for Ce-UiO-66 metal–organic frameworks (MOFs) is presented. The MOFs are obtained by energetically grinding the reagents, cerium ammonium nitrate (CAN) and the carboxylic linkers, in a mortar for a few minutes with the addition of a small amount of acetic acid (AcOH) as a modulator (8.75 equiv, 0.5 mL). The slurry is then transferred into a 2 mL vial and heated at 120 °C for 1 day. The MOFs have been characterized for their composition, crystallinity, and porosity and employed as heterogeneous catalysts for the photo-oxidation reaction of substituted benzylic alcohols to benzaldaldehydes under near-ultraviolet light irradiation. The catalytic performances, such as selectivity, conversion, and kinetics, exceed those of similar systems studied by chemical oxidation using similar Ce-MOFs as a catalyst. Moreover, the MOFs were found to be reusable up to three cycles without loss of activity. Density functional theory (DFT) calculations were used to fully describe the electronic structure of the best performing MOFs and to provide useful information on the catalytic activity experimentally observed

Low-lying meson spectrum of large NCN_C strongly coupled lattice QCD

We compute the low energy mass spectrum of lattice QCD in the large $N_C$ limit. Expanding around a gauge-invariant ground state, which spontaneously breaks the discrete chiral symmetry, we derive an improved strong-coupling expansion and evaluate, for any value of $N_C$, the masses of the low-lying states in the unflavored meson spectrum. We then take the 't Hooft limit by rescaling $g^2 N_C\to g^2$; the 't Hooft limit is smooth and no arbitrary parameters are needed. We find, already at the fourth order of the strong coupling perturbation theory, a very good agreement between the results of our lattice computation and the known continuum values.Comment: 43 pages, 1 figure. Minor corrections. One reference added in section

IDONEITÀ DEI TERRENI PIROCLASTICI DELL’AREA DI ROMA ALLA STABILIZZAZIONE A CALCE

Nella nota si presentano i primi risultati di un’indagine sperimentale rivolta allo studio dei fenomeni chimico-fisici che si sviluppano in terreni piroclastici a grana grossa (pozzolane laziali) stabilizzati a calce e al conseguente comportamento meccanico. Le indagini microstrutturali comprendono misure di porosità mediante adsorbimento di azot

The first route to highly stable crystalline microporous zirconium phosphonate metal–organic frameworks

The first crystalline microporous zirconium phosphonate metal–organic framework (UPG-1) was synthesized using the novel tritopic ligand 2,4,6-tris(4-(phosphonomethyl)phenyl)-1,3,5-triazine. Its crystal structure was solved ab initio from laboratory powder X-ray diffraction data. UPG-1 displays remarkable thermal stability and hydrolysis resistance and has a good absorption affinity towards n-butane and CO2

Solvent-free synthesis of halloysite-layered double hydroxide composites containing salicylate as novel, active fillers

Solvent-free syntheses provide an alternative path that reduces the use of hazardous substances. In this work, a sustainable synthesis of nanometric layered double hydroxide particles grafted over halloysite nanotubes (HNT@LDH) is reported using a mechanochemical technique. Samples loaded with different LDH percentage (100%, 50%, 40%, 30%, 20%, 10% with respect to the HNT content) were prepared and characterized. Spectroscopic and morphological characterizations allowed to select the sample with 20% by weight of LDH as the best composite (HNT@LDH20), wherein no LDH phase segregation was observed and the nanosheets were homogeneously grafted throughout the surface of the halloysite nanotubes. The combination of cationic and anionic clays in one filler enables the preparation of a composite which can be easily dispersed in a polymer and release active molecules. To this end, salicylate ions were incorporated into the layered double hydroxide nanoflakes of HNT@LDH20 and three intercalation strategies, comprising both solvent-free and traditional intercalating routes, were tested. Results of salicylate release tests indicate that the intercalating route used affects the amount of species hosted, the strength of the salicylate-LDH interactions and the drug release time, thus offering the possibility of selecting the most suitable method of drug incorporation to tune the salicylate content depending on a specific aim