101 research outputs found
Oxygen doping tuning in superconducting oxides by thermal annealing and hard X-ray irradiation
Spectroscopic and adsorptive studies of a thermally robust pyrazolato-based PCP
The pyrazolato-based PCP [Ni8(OH)4(OH2)2(PBP)6] (NiPBP, H2PBP = 4,4\u2019-bis(1H-pyrazol-4-yl)biphenyl), whose 3-D architecture is built upon octametallic hydroxo clusters reciprocally connected by the organic spaces, is a very promising candidate for gas adsorption applications, owing to its remarkable thermal stability (up to 400 \ub0C in air) and its high void volume (70%). As such, NiPBP was selected as a proof-of-concept material to demonstrate how an optimized set of solid state techniques can concur to create a comprehensive and coherent picture, relating (average and local) structural features to adsorptive properties. To this aim, the response of NiPBP toward different gases, retrieved by gas adsorption measurements (N2 at 77 K, in the low pressure region; H2 at 77 K, in the high pressure region), was explained in terms of local-level details, as emerged by coupling electronic, X-ray (absorption and emission), and variable temperature IR spectroscopy
Hard X-ray microprobe highlights the structure of multi-quantum wells in electroabsorption-modulated lasers for optoelectronics
Insight into Non Linearly Shaped Superconducting Whiskers via Synchrotron Nanoprobe
We managed to synthesize non-linear YBa2Cu3Ox whiskers, i.e. half loops or
kinked shapes, which are promising candidates for solid-state devices based on
the intrinsic Josephson effect and with improved electrical connections. We
report on a complete characterization of their structural properties via
synchrotron nanoprobe as well as laboratory single-crystal diffraction
techniques. This investigation allowed us to fully disclose the growth
mechanism, which leads to the formation of curved whiskers. The superconducting
properties are evaluated in comparison with the straight counterpart, revealing
a strong functional analogy and confirming their potential applicability in
superconducting electronic devices.Comment: 10 page
Structural and electronic characterization of nano-sized inorganic materials by X-ray Absorption Spectroscopies
Causality and the Entropy-Complexity Plane: Robustness and Missing Ordinal Patterns
We deal here with the issue of determinism versus randomness in time series.
One wishes to identify their relative weights in a given time series. Two
different tools have been advanced in the literature to such effect, namely, i)
the "causal" entropy-complexity plane [Rosso et al. Phys. Rev. Lett. 99 (2007)
154102] and ii) the estimation of the decay rate of missing ordinal patterns
[Amig\'o et al. Europhys. Lett. 79 (2007) 50001, and Carpi et al. Physica A 389
(2010) 2020-2029]. In this work we extend the use of these techniques to
address the analysis of deterministic finite time series contaminated with
additive noises of different degree of correlation. The chaotic series studied
here was via the logistic map (r = 4) to which we added correlated noise
(colored noise with f-k Power Spectrum, 0 {\leq} k {\leq} 2) of varying
amplitudes. In such a fashion important insights pertaining to the
deterministic component of the original time series can be gained. We find that
in the entropy-complexity plane this goal can be achieved without additional
computations.Comment: submitted to Physica
Progression of coronary artery calcification and cardiac events in patients with chronic renal disease not receiving dialysis
We tested for the presence of coronary calcifications in patients with chronic renal disease not on dialysis and studied its progression in 181 consecutive non-dialyzed patients who were followed for a median of 745 days. Coronary calcifications (calcium score) were tallied in Agatston units by computed tomography, and the patients were stratified into two groups by their baseline calcium score (100 U or less and over 100 U). Survival was measured by baseline calcium score and its progression. Cardiac death and myocardial infarction occurred in 29 patients and were significantly more frequent in those patients with calcium scores over 100 U (hazard ratio of 4.11). With a calcium score of 100 U or less, the hazard ratio for cardiac events was 0.41 and 3.26 in patients with absent and accelerated progression, respectively. Thus, in non-dialyzed patients, the extent of coronary calcifications was associated to cardiac events, and progression was an independent predictive factor of cardiac events mainly in less calcified patients. Hence, assessment of coronary calcifications and progression might be useful for earlier management of risk factors and guiding decisions for prevention of cardiac events in this patient population
Increase of Vascular Endothelial Growth Factor and Decrease of MCP-1 and Some Updated Epidemiology Aspects of Cystic Echinococcosis Human Cases in Calabria Region
Preliminary Assessment of Radiolysis for the Cooling Water System in the Rotating Target of {SORGENTINA}-{RF}
The SORGENTINA-RF project aims at developing a 14 MeV fusion neutron source featuring an emission rate in the order of 5-7 x 10(13) s(-1). The plant relies on a metallic water-cooled rotating target and a deuterium (50%) and tritium (50%) ion beam. Beyond the main focus of medical radioisotope production, the source may represent a multi-purpose neutron facility by implementing a series of neutron-based techniques. Among the different engineering and technological issues to be addressed, the production of incondensable gases and corrosion product into the rotating target deserves a dedicated investigation. In this study, a preliminary analysis is carried out, considering the general layout of the target and the present choice of the target material
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