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Natural time analysis of critical phenomena: The case of acoustic emissions in triaxially deformed Etna basalt 总被引:1,自引:0,他引:1
Acoustic emissions exhibit complex correlations between space, time, and magnitude. As such, they present a unique example for a complex time series. We apply the recently introduced method of natural time analysis, which enables the detection of long-range temporal correlations even in the presence of heavy tails and find that the acoustic emissions exhibits features similar to that of other equilibrium or non-equilibrium critical systems such as worldwide seismicity as presented in the Centennial earthquake catalogue which includes global seismicity events with magnitude Mw>7.0. These results support the universal behaviour of the fracturing processes from the laboratory to the global scale. 相似文献
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In the present work, dielectric and conductivity measurements in the frequency range of 10 mHz–1 MHz were carried out by means of a high-resolution broadband spectrometer on non-swelling bentonite samples, at various low levels of hydration. The evolution of dielectric response was also examined after annealing of the samples up to 260 °C. Conductivity results in conjunction with the electric modulus representation (M1) is proved to be the most suitable for the analysis of the dielectric data. Dielectric response is dominated by ionic (surface and bulk) conductivity as well as by grain polarization due to migration of ions along the clay layers. Both mechanisms are strongly affected by the concentration of bound water and the thermodielectric effect. Havrilliak–Negami dielectric relaxation functions were used to model the observed relaxations mechanisms in modulus formalism and the fitting parameters were evaluated at various water contents of the measured samples. 相似文献
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Filippos Vallianatos 《Journal of Physics and Chemistry of Solids》2012,73(4):550-553
The study of isothermal depolarization current relaxation during the cement hardening process follows a generalized exponential function, which explicitly introduces hierarchically constrained dynamics and macroscopic interactions. The interactions are associated to the non-extensive entropy parameter q, which varies during hardening evolution. Combining ideas of Levy and Tsallis statistics we argue that a Levy walk type mechanism can organize the geometry of the cement mortar heterogeneous system. The estimation of non-extensive q parameter safe concludes that cement's hardening is a subextensive process. 相似文献
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MacDonald C Smith C Michopoulos F Weaver R Wilson ID 《Rapid communications in mass spectrometry : RCM》2011,25(13):1787-1793
The application of sulphur-specific detection via ultra-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (UPLC/ICPMS) to detect and quantify the glutathione (GSH)-adducts produced via the in vitro formation of reactive metabolites is demonstrated. The adducts were formed in human liver microsomes supplemented with unlabelled GSH for clozapine. The calculation of adduct concentration was performed via comparison of the peak areas to calibration curves constructed from omeprazole, a sulphur-containing compound over the range of 0.156 to 15.62 μM of sulphur with a detection limit of 1.02 ng of sulphur on-column. Identification of the adducts was performed using conventional UPLC/time-of-flight (TOF)-MS with the calculation of clozapine intrinsic clearance carried out by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). The use of ICPMS in this way appears to offer a novel, rapid and sensitive means of determining the quantity of GSH conjugates with the combined adducts producing 0.9 μM of reactive metabolite out of a total of 3.5 μM of metabolites. The GSH adduct therefore represents 26% of this total produced as a result of the metabolism of drug to reactive species. 相似文献
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Fracturing processes within solid Earth materials are inherently a complex phenomenon so that the underlying physics that control fracture initiation and evolution still remain elusive. However, universal scaling relations seem to apply to the collective properties of fracturing phenomena. In this article we present a statistical physics approach to fracturing based on the framework of non-extensive statistical physics (NESP). Fracturing phenomena typically present intermittency, multifractality, long-range correlations and extreme fluctuations, properties that motivate the NESP approach. Initially we provide a brief review of the NESP approach to fracturing and earthquakes and then we analyze stress and stress direction time series within Arctic sea ice. We show that such time series present large fluctuations and probability distributions with “fat” tails, which can exactly be described with the q-Gaussian distribution derived in the framework of NESP. Overall, NESP provide a consistent theoretical framework, based on the principle of entropy, for deriving the collective properties of fracturing phenomena and earthquakes. 相似文献
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Tarushi A Kastanias F Psycharis V Raptopoulou CP Psomas G Kessissoglou DP 《Inorganic chemistry》2012,51(14):7460-7462
The interaction of ZnCl(2) with 2-dipyridylketonoxime (=Hpko) and flufenamic acid (=Hfluf) in a basic methanolic solution leads to the formation of a hexanuclear 24-membered metallacoronate, [Zn(6)(OH)(2)(pko)(4)(fluf)(6)] (1), with a [Zn-O-C-O] repeat unit and a nonsteroidal antiinflammatory drug as the constructing ligand. Compound 1 retains its structure in a dimethyl sulfoxide solution, as shown by (1)H NMR spectroscopy and molar conductance. 相似文献
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Is plate tectonics a case of non-extensive thermodynamics? 总被引:1,自引:0,他引:1
Bird (2003) [5] proposed that the distribution of areas of the tectonic plates follows a power law and that this distribution fitted well with the concepts of a few major plates and a hierarchical self-similar organization of blocks at the boundary scale, a fractal plate distribution and a self-organized system. Here we apply the concepts of non-extensive statistical mechanics (NESM) to plate tectonics. The application of NESM is appropriate to systems such as tectonic plates where non-linearity, long-range interactions, memory effects and scaling are important. We calculate the probability density function for the areas of the tectonic plates. Our results show that three classes (small, intermediate and large) of tectonic plates can be distinguished, which is consistent with the observations of Bird. Furthermore, taking into account that for the intermediate class of tectonic plates the cumulative frequency distribution behaves as a power law with exponent 1/3, we estimate a thermodynamic q parameter of q=1.75, which supports the conclusion that the plate tectonics system is a sub-extensive one. 相似文献
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Dr. Ariel Hecht Patrick Commiskey Filippos Lazaridis Prof. Panos Argyrakis Prof. Raoul Kopelman 《Chemphyschem》2014,15(16):3444-3446
We use fractal analysis to calculate the protein concentration in a rotating magnetic assembly of microbeads of size 1 μm, which has optimized parameters of sedimentation, binding sites and magnetic volume. We utilize the original Forrest–Witten method, but due to the relatively small number of bead particles, which is of the order of 500, we use a large number of origins and also a large number of algorithm iterations. We find a value of the fractal dimension in the range 1.70–1.90, as a function of the thrombin concentration, which plays the role of binding the microbeads together. This is in good agreement with previous results from magnetorotation studies. The calculation of the fractal dimension using multiple points of reference can be used for any assembly with a relatively small number of particles. 相似文献