Electrically Conducting PbyOx–SiO2 Glass Films Deposited by Reactive Radio-Frequency Magnetron Sputtering

Lead silicate glass films were deposited on sapphire substrates in different plasmas (100% Ar; 20% H₂+ 80% Ar; 5% O₂+ 95% Ar) by reactive radio-frequency magnetron sputtering. The stoichiometry of the films, determined by Rutherford backscattering spectroscopy, changed with the deposition conditions. X-ray diffractometry analysis showed the presence of metallic Pb in the samples sputtered in H₂-containing plasma. The room-temperature sheet resistance of the films ranged from >10¹⁶Ω/□ (O₂-containing atmosphere) to about 10³Ω/□ (H₂-containing atmosphere).     

Electrostatic effects on the thermodynamics of protonation of reduced plastocyanin

The L12E, L12K, Q88E, and Q88K variants of spinach plastocyanin have been electrochemically investigated. The effects of insertion of net charges near the metal site on the thermodynamics of protonation and detachment from the copper(I) ion of the His87 ligand have been evaluated. The mutation-induced changes in transition enthalpy cannot be explained by electrostatic considerations. The existence of enthalpy/entropy (H/S) compensation within the protein series indicates that solvent-reorganization effects control the differences in transition thermodynamics. Once these compensating contributions are factorized out, the resulting modest differences in transition enthalpies turn out to be those that can be expected on purely electrostatic grounds. Therefore, this work shows that the acid transition in cupredoxins involves a reorganization of the H-bonding network within the hydration sphere of the molecule in the proximity of the metal center that dominates the observed transition thermodynamics and masks the differences that are due to protein-based effects.     

Mechatronic analysis of a complex transmission chain for performance optimization in a machine tool

Mechatronic models of complex mechanical systems allow to assemble reliable simulators, which can be used to test alternative choices made at component level. When the complexity of the system is significant, however, it is neither easy to model the interactions among different elements, nor immediate to identify the components responsible for a possible loss of performance of the system. Based on a detailed linear model of a complex transmission chain used within a large size machine tool, this paper contributes presenting a methodology, supported by modal analysis, to quantify the sensitivity of each vibration mode to the stiffness of each component. A nonlinear simulator of the transmission has been derived, too, and its remarkable performance in reproducing the experiments is demonstrated. Insight on the role of Coulomb friction is also provided, together with a practical way to split the overall friction between motor and load sides.     

Thermodynamic and kinetic aspects of the electron transfer reaction of bovine cytochrome c immobilized on 4-mercaptopyridine and 11-mercapto-1-undecanoic acid films

Bovine cytochrome c (cyt c) was adsorbed on a polycrystalline gold electrode coated with 4-mercaptopyridine and 11-mercapto-1-undecanoic acid self-assembled monolayers (SAMs) and the thermodynamics and kinetics of the heterogeneous protein-electrode electron transfer (ET) reaction were determined by cyclic voltammetry. The E°′ values for the immobilized protein were found to be lower than those for the corresponding diffusing species. The thermodynamic parameters for protein reduction ( and ) indicate that the stabilization of the ferric state due to protein–SAM interaction is enthalpic in origin. The kinetic data suggest that a tunneling mechanism is involved in the ET reaction: the distance between the redox center of the protein and the electrode surface can be efficiently evaluated using the Marcus equation.     

Surface plasmon resonance study on the optical sensing properties of nanometric polyimide films to volatile organic vapours

The optical sensing properties of nanometric polyimide films towards ethanol and methanol vapours have been investigated by surface plasmon resonance technique. To this purpose polyimide sensing layers have been deposited onto gold/glass substrates by glow-discharge-induced vapour deposition polymerization technique. The sensible layer shows reversible and stable responses to different concentrations of methanol and ethanol vapours. A linear dependence between the change in reflectivity and the vapours concentration is observed being the sensitivity to both vapours similar, however, the response is larger in presence of ethanol vapours. Numerical fitting routines on surface plasmon resonance curves indicate that optical changes are motivated by an absorption process of the analyte. This produces a detectable increase of the real refractive index and a swelling process in the polyimide layer.     

Probability of inelastic nuclear interactions of high-energy protons in a bent crystal

Probability of inelastic nuclear interactions in a short bent silicon crystal for its orientations optimal for channeling and volume reflection was investigated using 400 GeV/c protons of the CERN SPS. The contribution of nuclear interactions from channeled protons was observed to be about 3–4% of the probability for the amorphous orientation. For the crystal orientation optimal for volume reflection the nuclear interaction probability of protons was a few percents larger than in the amorphous case. It was shown that in the limiting case of a quasi parallel beam realizing for the collider beam halo the inelastic nuclear losses should decrease by more than five times, which is an additional advantage of a crystal as a primary collimator for the LHC collimation system.     

A certified,corecursive implementation of exact real numbers

We implement exact real numbers in the logical framework Coq using streams, i.e., infinite sequences, of digits, and characterize constructive real numbers through a minimal axiomatization. We prove that our construction inhabits the axiomatization, working formally with coinductive types and corecursive proofs. Thus we obtain reliable, corecursive algorithms for computing on real numbers.     

On modelling of curl in multi-ply paperboard

This paper describes a grey-box model for the curl and twist of the carton board produced at AssiDomän Frövi, Sweden. The main equations are based on classical lamination theory of composite materials, and each constituent ply is considered as a macroscopic homogeneous, elastic medium. The model used data from June to September 2004, and shows a general agreement between predicted and measured curvatures. The data were cleaned from outliers by means of the Hampel filter, a nonlinear moving window filter, and with a model based method. Regularization and backwards elimination were used to cope with the low identifiability of the problem. The model was then complemented with a sub-model of immeasurable/unmodelled disturbances estimated with an extended Kalman filter.