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George M. Fuller Alexander Kusenko Kalliopi Petraki 《Physics letters. [Part B]》2009,670(4-5):281-284
We consider sterile neutrinos with rest masses 0.2 GeV and with vacuum flavor mixing angles θ2>10−8 for mixing with τ-neutrinos, or 10−8<θ2<10−7 for mixing with muon neutrinos. Such sterile neutrinos could augment core collapse supernova shock energies by enhancing energy transport from the core to the vicinity of the shock front. The decay of these neutrinos could produce a flux of very energetic active neutrinos, detectable by future neutrino observations from galactic supernova. The relevant range of sterile neutrino masses and mixing angles can be probed in future laboratory experiments. 相似文献
2.
G. Chaidogiannos F. Petraki N. Glezos S. Kennou S. Ne?p?rek 《Applied Physics A: Materials Science & Processing》2009,96(3):763-767
The class of sodium salts of sulphonated metal phthalocyanines (MePCS
x
, S = SO3Na, x=1–4) was investigated as a p-type channel component in organic field-effect transistors (OFETs). The solubility of these
materials appears to be enhanced compared to their non-sulphonated counterparts (MePCs). We fabricated transistors based on
MePCS
x
varying the central metal atom (Me = Ni, Co, Zn, Al) and we evaluated the dependence of transistor performance on the nature
of the central atom and the degree of sulphonation. The best results were obtained in the case of Ni and low sulphur content.
In this case the mobility value is μ=1.08 cm2 V−1 s−1 and the on/off current ratio ∼103. The degree of sulphonation affects the electric field inside the active film in a way analogous to the case of polyelectrolyte-gated
OFETs. The Na+ counter ions present in the channel contribute to the device characteristics but their concentration should be controlled
in order to optimize device performance. 相似文献
3.
Dimitrios Nikolopoulos Ermioni Petraki Efstratios Vogiannis Yiannis Chaldeos Panayiotis Yannakopoulos Sofia Kottou Constantinos Nomicos John Stonham 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):203-219
This paper addresses issues of self-affinity, long-memory and self-organisation in variations of radon in soil recorded in Lesvos Island, Greece. Several techniques were employed, namely (a) power-law wavelet spectral fractal analysis, (b) estimation of Hurst exponents through (b1) rescaled-range, (b2) roughness-length, (b3) variogram and (a), (c) detrended fluctuation analysis, (d) investigation of fractal dimensions and (e) analysis of five block entropies: (e1) Shannon entropy, (e2) Shannon entropy per letter, (e3) conditional entropy, (e4) Tsallis entropy, and (e5) normalised Tsallis entropy. Long-lasting antipersistency was identified during a period of anomalous radon variations following fractional Brownian modelling. Remaining variations did not exhibit analogous behaviour and followed fractional Gaussian modelling. Antipersistent power-law-beta-exponent-values between 1.5 and 2.0 were detected during anomalies. Persistent values were also found. Hurst exponents were mainly within 0 < H < 0.5. Some persistent exponents (0.5 < H < 1) were also observed. Fractal dimensions were within 1.5 < D < 2. Radon anomalies presented lower fractal dimensions. Shannon entropy ranged between 0.77 ≤ H(n) ≤ 2.38, Shannon entropy per letter, between 0.19 ≤ h (n) ≤ 0.59, conditional entropy, between 0.01 ≤ h (n) ≤ 0.58, Tsallis entropy, between 0.55 ≤ S q ≤ 1.01 and normalised Tsallis entropy between, 0.98 ≤ $\hat{S}$ ≤ 5.42 (block-size n = 4). Entropies were lower during anomalies, indicating strong self-organisation. Persistency–antipersistency switching was observed, consistent with long-memory dynamics. Potential geological sources were discussed. The asperity-model was proposed. Findings were compared to results obtained under analogous methodologies in Ileia, Greece. 相似文献
4.
Stefopoulos AA Chochos CL Prato M Pistolis G Papagelis K Petraki F Kennou S Kallitsis JK 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(28):8715-8724
Facile routes for the synthesis of hybrid materials consisting of regioregular poly(3-octylthiophene)s covalently attached to single-wall carbon nanotubes are presented for the first time. These materials are easily processable using common organic solvents, and at the same time combine the properties of regioregular poly(3-alkylthiophene)s with those of single-wall carbon nanotubes. Moreover, studies of the properties of these materials have provided strong evidence for an electron transfer from the regioregular poly(3-octylthiophene) to the single-wall carbon nanotube. 相似文献
5.
Dimitrios Nikolopoulos Aftab Alam Ermioni Petraki Michail Papoutsidakis Panayiotis Yannakopoulos Konstantinos P. Moustris 《Entropy (Basel, Switzerland)》2021,23(3)
This paper utilises statistical and entropy methods for the investigation of a 17-year PM10 time series recorded from five stations in Athens, Greece, in order to delineate existing stochastic and self-organisation trends. Stochastic patterns are analysed via lumping and sliding, in windows of various lengths. Decreasing trends are found between Windows 1 and 3500–4000, for all stations. Self-organisation is studied through Boltzmann and Tsallis entropy via sliding and symbolic dynamics in selected parts. Several values are below −2 (Boltzmann entropy) and 1.18 (Tsallis entropy) over the Boltzmann constant. A published method is utilised to locate areas for which the PM10 system is out of stochastic behaviour and, simultaneously, exhibits critical self-organised tendencies. Sixty-six two-month windows are found for various dates. From these, nine are common to at least three different stations. Combining previous publications, two areas are non-stochastic and exhibit, simultaneously, fractal, long-memory and self-organisation patterns through a combination of 15 different fractal and SOC analysis techniques. In these areas, block-entropy (range 0.650–2.924) is significantly lower compared to the remaining areas of non-stochastic but self-organisation trends. It is the first time to utilise entropy analysis for PM10 series and, importantly, in combination with results from previously published fractal methods.Data Set License: license under which the dataset is made available (CC0, CC-BY, CC-BY-SA, CC-BY-NC, etc.) 相似文献
6.
Basova T Plyashkevich V Petraki F Peisert H Chassé T 《The Journal of chemical physics》2011,134(12):124703
The μ-(oxo)bis[phthalocyaninato] aluminum(III) (AlPc)(2)O films, with the crystallites oriented preferably in one direction, were obtained via chemical transformation of chloroaluminum(III) phthalocyanine AlClPc film upon its annealing in magnetic field. A comparative analysis of the influence of postdeposition annealing without and under applied magnetic field of 1 T on composition and morphology of AlClPc films has been carried out. The chemical transformation of AlClPc to (AlPc)(2)O on the substrate surface is studied by the methods of UV-vis and infrared spectroscopies, Raman, x-ray photoelectron spectroscopy as well as atomic force microscopy. Two interesting effects were observed upon heating the AlClPc films in magnetic field of 1 T. First, the temperature of the chemical transformation of AlClPc to (AlPc)(2)O decreased from 300 °C to 200 °C when magnetic field was applied during postdeposition annealing. Second, the formation of (AlPc)(2)O films with elongated crystallites with a preferential orientation was observed. The heating of (AlPc)(2)O films in a magnetic field at the same conditions did not demonstrate any effect on the structure and morphology of these films. 相似文献
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