Exploring the Porosity in Ceramics at the nm Scale: From Understanding Historical Ceramics to Innovative Materials Design

Ceramics are complex objects and a rich source of information: they constitute a large part of the staple memory of past and present human activities. A deep understanding of traditional ceramics is an essential key to designing new ceramic materials. The demanding synthesis of ceramics with fine-tuned properties, such as enhanced mechanical, electrical, optical or magnetic characteristics, must be associated with cutting-edge analysis procedures in order to improve the engineering process. In this context, we describe a neutron-based non-destructive approach to investigating the nanoporosity of an historical pottery matrix as an effective investigation technique for exploring both traditional and advanced ceramic materials.     

Surface and transport properties of Au-In liquid alloys

Thermodynamic quantities on Au-In liquid alloys have been used as the input data for the interaction parameter calculations in the framework of the complex formation model (CFM). Once the interaction energies are computed the surface (surface tension and surface composition) and transport properties (chemical diffusion and viscosity) as well as the microscopic functions (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter) have been calculated. The concentration and temperature dependent surface tension values have been compared with our new set of experimental data, obtained by the large drop method in the temperature range of T = 1273-1493 K. The anomalous change of surface tension for some alloy compositions may be attributed to a retention of order in the Au-In melts which is similar to the atomic arrangement in solid Au-In.     

Interactions of the solar neutrinos with the deuterons

The beta decay of ³¹Cl has been studied with a silicon detector array and a HPGe detector at the IGISOL facility. Previously controversial proton peaks have been confirmed to belong to ³¹Cl and a new proton group with an energy of 762(14) keV has been found. Proton captures to this state at 6921(15) keV in ³¹S can have an effect on the reaction rate of ³⁰P(p,γ) in ONe novae. Gamma rays of 1249.1(14) keV and 2234.5(8) keV corresponding to the de-excitations of the first two excited states in ³¹S have been measured. No beta-delayed protons from the IAS have been observed.     

DeuteronA(q 2 ) structure function in the low and mediumq 2 range

The deuteronA(q ² ) structure function is calculated up toq ²=20 fm^–2 with the Paris potential including relativistic nucleonic and mesonic corrections. Different parametrizations (Iachello et al., Galster et al., Höhler et al., Gari and Krümpelmann (GK)) of the nucleon electromagnetic form factors (emff) are used. Unlike the data of Simon et al., those recently taken at Saclay are reasonably well reproduced by our full predictions for the first three emff considered. On the contrary, the predictions for the GK model fail to fit the Saclay data. The dependence ofA(q ² ) on the cut-off masses of the hadronic form factors is also investigated.     

Sulla risolubilita' degli operatori differenziali invarianti sul gruppo di Heisenberg

In questa nota si considera il problema della risolubilità per operatori del secondo ordine, invarianti a sinistra e omogenei, sul gruppo di HeisenbergH _n. Si presenta un approccio al problema basato sul prolungamento analitico dei coefficienti degli operatori, a partire dai risultati noti per il sub-Laplaciano. I dettagli sono contenuti in due articoli degli autori, in collaborazione con F. De Mari [DPR] e D. Müller [MPR]. Conferenza tenuta da F. Ricci il 25 ottobre 1995     

Dissipative Synthetic DNA‐Based Receptors for the Transient Loading and Release of Molecular Cargo

Supramolecular chemistry is moving into a direction in which the composition of a chemical equilibrium is no longer determined by thermodynamics but by the efficiency with which kinetic states can be populated by energy consuming processes. Herein, we show that DNA is ideally suited for programming chemically fueled dissipative self‐assembly processes. Advantages of the DNA‐based systems presented in this study include a perfect control over the activation site for the chemical fuel in terms of selectivity and affinity, highly selective fuel consumption that occurs exclusively in the activated complex, and a high tolerance for the presence of waste products. Finally, it is shown that chemical fuels can be used to selectively activate different functions in a system of higher complexity embedded with multiple response pathways.