Direct Experimental Evidence of the Statistical Nature of the Electron Gas in Superconducting Films

In an Nb film an alternate electrical current is partitioned at a Y-shaped obstacle into two splitted beams. The intensity-fluctuation correlation of the two beams (cross-correlation) and the intensity- fluctuation correlation of one beam (auto-correlation) are measured within a low-frequency bandwidth as a function of the incident beam intensity, at temperatures T above or below the temperature Tc of the superconductive transition. The results of these measurements reveal the statistical nature of the electron gas in the normal film and in the superconducting film. The conceptual scheme of the present experiment is a version of the Hanbury Brown and Twiss (HBT) experiment, here adopted for a gas of particles in a solid

Modeling Escape from a One-Dimensional Potential Well at Zero or Very Low Temperatures

The process of activation out a one-dimensional potential is investigated systematically in zero and nonzero temperature conditions. The features of the potential are traced through statistical escape out of its wells whose depths are tuned in time by a forcing term. The process is carried out on the damped pendulum system imposing specific initial conditions on the potential variable. While for relatively high values of the dissipation the statistical properties follow a behavior that can be derived from the standard Kramers model, decreasing the dissipation we observe responses/deviations which have regular dependencies on initial conditions, temperature, and loss parameter itself. It is shown that failures of the thermal activation model are originated at low temperatures, and very low dissipation, by the initial conditions and intrinsic, namely T=0, characteristic oscillations of the potential-generated dynamical equation.Comment: 25 pages and 13 Figure

Quantum Coherence in Loopless Superconductive Networks

Measurements indicating that planar networks of superconductive islands connected by Josephson junctions display long-range quantum coherence are reported. The networks consist of superconducting islands connected by Josephson junctions and have a tree-like topological structure containing no loops. Enhancements of superconductive gaps over specific branches of the networks and sharp increases in pair currents are the main signatures of the coherent states. In order to unambiguously attribute the observed effects to branches being embedded in the networks, comparisons with geometrically equivalent-but isolated-counterparts are reported. Tuning the Josephson coupling energy by an external magnetic field generates increases in the Josephson currents, along the above-mentioned specific branches, which follow a functional dependence typical of phase transitions. Results are presented for double comb and star geometry networks, and in both cases, the observed effects provide positive quantitative evidence of the predictions of existing theoretical models

Exploiting the Properties of Ti-Doped CVD-Grown Diamonds for the Assembling of Electrodes

A hybrid chemical vapor deposition (CVD)‐powder flowing technique specifically developed in lab has been employed to produce high‐quality polycrystalline diamond layers containing Ti inclusions. Morphology, structural features, and surface composition of nanocomposite diamond‐based samples produced by different growth times have been analyzed by scanning electron microscopy, Raman and Auger spectroscopy, respectively. The CVD methodology adopted for the Ti incorporation in the diamond lattice does not perturb the crystalline quality of the diamond matrix, therefore maintaining the outstanding properties of the C‐sp3 phase. The functional properties of the nanocomposite layers have been tested by nanoindentation and I–V measurements. The electrochemical performance of the diamond/Ti electrodes is evaluated by performing cyclic voltammetry in different media, namely, acidic, neutral, and basic aqueous solutions, and by estimating the rate constant of heterogeneous electron transfer to diamond surface for the ferro/ferricyanide redox couple. The rather good electrochemical performances, the mechanical strength, and the chemical inertness of the Ti‐doped diamond electrodes produced by the CVD approach, comply with the whole set of technological requirements, such as robustness, long durability, and biocompatibility, required for use in hostile environments or in biological systems

The role of substrate temperature and magnetic filtering for DLC by cathodic arc evaporation

Diamond-like carbon (DLC) films were deposited using two different types of high current arc evaporation. The first process used a magnetic particle filter to remove droplets from the plasma. For the second process, the samples were put into a metallic cage which was placed directly above the plasma source. For both processes, we varied the substrate temperature from 21 to 350 °C in order to investigate the temperature effect. The samples were characterized using SEM, AFM, XPS, Raman Spectroscopy, Ellipsometry, Photometry, and Nano Indentation in order to compare both methods of deposition and provide a careful characterization of such DLC films. We found that the sp3 content and the hardness can be precisely adjusted by changing the substrate temperature. Furthermore, in the case of unfiltered deposition, the optical constants can be shifted in the direction of higher absorbance in order to produce black and hard carbon coatings. © 2019 by the authors

Biophotons and emergence of quantum coherence : a diffusion entropy analysis

We study the emission of photons from germinating seeds using an experimental technique designed to detect light of extremely small intensity. We analyze the dark count signal without germinating seeds as well as the photon emission during the germination process. The technique of analysis adopted here, called diffusion entropy analysis (DEA) and originally designed to measure the temporal complexity of astrophysical, sociological and physiological processes, rests on Kolmogorov complexity. The updated version of DEA used in this paper is designed to determine if the signal complexity is generated either by non-ergodic crucial events with a non-stationary correlation function or by the infinite memory of a stationary but non-integrable correlation function or by a mixture of both processes. We find that dark count yields the ordinary scaling, thereby showing that no complexity of either kinds may occur without any seeds in the chamber. In the presence of seeds in the chamber anomalous scaling emerges, reminiscent of that found in neuro-physiological processes. However, this is a mixture of both processes and with the progress of germination the non-ergodic component tends to vanish and complexity becomes dominated by the stationary infinite memory. We illustrate some conjectures ranging from stress induced annihilation of crucial events to the emergence of quantum coherence

Prescription appropriateness of anti-diabetes drugs in elderly patients hospitalized in a clinical setting: evidence from the REPOSI Register

Diabetes is an increasing global health burden with the highest prevalence (24.0%) observed in elderly people. Older diabetic adults have a greater risk of hospitalization and several geriatric syndromes than older nondiabetic adults. For these conditions, special care is required in prescribing therapies including anti- diabetes drugs. Aim of this study was to evaluate the appropriateness and the adherence to safety recommendations in the prescriptions of glucose-lowering drugs in hospitalized elderly patients with diabetes. Data for this cross-sectional study were obtained from the REgistro POliterapie-Società Italiana Medicina Interna (REPOSI) that collected clinical information on patients aged ≥ 65 years acutely admitted to Italian internal medicine and geriatric non-intensive care units (ICU) from 2010 up to 2019. Prescription appropriateness was assessed according to the 2019 AGS Beers Criteria and anti-diabetes drug data sheets.Among 5349 patients, 1624 (30.3%) had diagnosis of type 2 diabetes. At admission, 37.7% of diabetic patients received treatment with metformin, 37.3% insulin therapy, 16.4% sulfonylureas, and 11.4% glinides. Surprisingly, only 3.1% of diabetic patients were treated with new classes of anti- diabetes drugs. According to prescription criteria, at admission 15.4% of patients treated with metformin and 2.6% with sulfonylureas received inappropriately these treatments. At discharge, the inappropriateness of metformin therapy decreased (10.2%, P < 0.0001). According to Beers criteria, the inappropriate prescriptions of sulfonylureas raised to 29% both at admission and at discharge. This study shows a poor adherence to current guidelines on diabetes management in hospitalized elderly people with a high prevalence of inappropriate use of sulfonylureas according to the Beers criteria

Quantum Coherence in Loopless Superconductive Networks

Measurements indicating that planar networks of superconductive islands connected by Josephson junctions display long-range quantum coherence are reported. The networks consist of superconducting islands connected by Josephson junctions and have a tree-like topological structure containing no loops. Enhancements of superconductive gaps over specific branches of the networks and sharp increases in pair currents are the main signatures of the coherent states. In order to unambiguously attribute the observed effects to branches being embedded in the networks, comparisons with geometrically equivalent—but isolated—counterparts are reported. Tuning the Josephson coupling energy by an external magnetic field generates increases in the Josephson currents, along the above-mentioned specific branches, which follow a functional dependence typical of phase transitions. Results are presented for double comb and star geometry networks, and in both cases, the observed effects provide positive quantitative evidence of the predictions of existing theoretical models

Gas sensor based on single wall carbon nanotubes

Single-walled carbon nanotubes (SWNTs) are nowadays one of the most investigated materials and the realization of ordered SWNT structures is of fundamental importance for the improvement of many technological fields, from the non-linear optics to the realization of transistor, to the assembly of gas sensing devices. A SWNT is formed by rolling a graphene sheet into a seamless cylinder with a diameter on the nanometer scale. The individual SWNTs are joined each other and assembled into bundles by Van der Waals forces. Guest molecules can potentially interact with SWNTs via the outer surfaces of bundles, the inside of the tubes and /or the interstitial channels between the tubes in a bundle. These different situations are expected to play an important role in tuning the guest molecule/SWNT interaction during gas adsorption and/or desorption, and have been investigated theoretically and experimentally using different approaches. In particular, the interaction between gaseous molecules and SWNTs has been investigated from different point of view, including gas storage and gas detection through modification of electronic and thermal properties or through modification of the field emission properties. Compared with conventional solid-state sensors, that typically operate at temperatures over 200 °C, and conducting polymers-based sensors, that provide only limited sensitivity, sensing devices assembled with single-wall nanotubes can exhibit high sensitivity and fast response time at room temperature. Due to the high surface area of nanotubes, a little amount of nanotube material can provide many sites for gas interaction. The accessibility of these sites depends on the status of aggregation of the nanotubes. Our preliminary studies suggested that the sensitivity of a nanotube-based device can be optimized controlling the organization of the SWNTs. Ordered bundles of SWNTs exhibit indeed a sensitivity double with respect to that of a disordered deposit. This is likely due to the enhancement of surface area for organized SWNT systems with respect to randomly placed SWNT bundles. Hence, aligned nanotubes can serve as a very efficient material for use in gas detection. Directionality of SWNT can be obtained directly during the synthesis process, or after manipulation of dispersed nanotubes, by mean of several methods, such as filtration/deposition from suspension in strong magnetic fields, field emission, electrophoresis or dielectrophoretical processes. In particular the use of electric fields to move, position and align SWNTs has been reported in recent papers and the results indicate that both the electrophoresis (EP) and dielectrophoresis (DEP) routes have potential advantages for arranging nanotubes in controlled systems. Beyond the sensitivity, another severe constraint for gas detection is the time either for the reset of the sensor after exposure to the gas, either for the acceleration of the response itself. Since practical applications can be severely limited by slow absorption/desorption processes, we felt it worthwhile to investigate in a systematic way some physical parameters affecting the sensor response. In this thesis we present a study of NH3 ,NOx and H2 detection using organized SWNTs as sensing material and an innovative procedure to improve the time response of the sensor by applying a back gate voltage. Moreover study on gas detection and gas storage were done using QCM sensor

I Gessi di Monte Mauro. Studio multidisciplinare di un’area carsica nella Vena del Gesso romagnola

L\u2019opera affronta la sezione centrale dei gessi romagnoli, caratterizzata dalla massima elevazione dell\u2019affioramento (Monte Mauro; 515 m slm secondo le carte IGM), nonch\ue9 da una naturalit\ue0 pi\uf9 accentuata rispetto agli altri settori della Vena del Gesso. L\u2019areale su cui si sono concentrati gli studi va da Monte della Volpe a Col Vedreto, passando per la sella di Ca\u2019 Faggia, Monte Mauro, Monte Incisa e Co\u2019 di Sasso (comuni di Brisighella, Riolo Terme e Casola Valsenio, RA): un territorio integralmente protetto, a partire dal 2005, dal Parco regionale della Vena del Gesso Romagnola. Le indagini sono spaziate, in un\u2019ottica interdisciplinare, dalla geologia al carsismo, agli studi naturalistici, all\u2019archeologia, a studi storico-geografici. Un ulteriore capitolo \ue8 poi dedicato alle tematiche gestionali connesse a questa area, che racchiude le due pi\uf9 estese zone A (a protezione integrale e accesso normalmente interdetto) dell\u2019intero Parco regionale della Vena del Gesso Romagnola, ovvero la forra del Rio Basino e le rupi sud di Monte Mauro. Le ricerche sono partite dal recupero e dalla rivisitazione critica di tutti i dati precedenti, passando poi a nuove indagini protrattesi in modo continuativo tra il 2016 e il 2018