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991.
Parlitz U Hornstein A Engster D Al-Bender F Lampaert V Tjahjowidodo T Fassois SD Rizos D Wong CX Worden K Manson G 《Chaos (Woodbury, N.Y.)》2004,14(2):420-430
The hysteretic nonlinear dependence of pre-sliding friction force on displacement is modeled using different physics-based and black-box approaches including various Maxwell-slip models, NARX models, neural networks, nonparametric (local) models and dynamical networks. The efficiency and accuracy of these identification methods is compared for an experimental time series where the observed friction force is predicted from the measured displacement. All models, although varying in their degree of accuracy, show good prediction capability of pre-sliding friction. Finally, we show that even better results can be achieved by using an ensemble of the best models for prediction. 相似文献
992.
G. Giardina G. Fazio A. Lamberto A. I. Muminov A. K. Nasirov U. T. Yakhshiev R. Palamara R. Ruggeri 《Acta Physica Hungarica A》2004,19(1-2):101-108
We study the effect of the entrance channel and the shell structure of reacting massive nuclei on the fusion mechanism and the formation of evaporation residues of heavy and superheavy nuclei. In the framework of the combined dinuclear system concept and advanced statistical model, we analyze the reactions 32S+182W, 48Ti+166Er and 60Ni+154Sm leading to 214Th*, and the reactions 48Ca+248Cm and the 48Ca+249Cf leading to the 296116 and 297118 compound nuclei, respectively. 相似文献
993.
Based on Monte Carlo simulations, the stable magnetization configurations of an antiferromagnet on a quasiperiodic tiling are derived theoretically. The exchange coupling is assumed to decrease exponentially with the distance between magnetic moments. It is demonstrated that the superposition of geometric frustration with the quasiperiodic ordering leads to a three-dimensional noncollinear antiferromagnetic spin structure. The structure can be divided into several ordered interpenetrating magnetic supertilings of different energy and characteristic wave vector. The number and the symmetry of subtilings depend on the quasiperiodic ordering of atoms. 相似文献
994.
Rosner JL Adam NE Alexander JP Berkelman K Cassel DG Duboscq JE Ecklund KM Ehrlich R Fields L Galik RS Gibbons L Gray R Gray SW Hartill DL Heltsley BK Hertz D Jones CD Kandaswamy J Kreinick DL Kuznetsov VE Mahlke-Krüger H Meyer TO Onyisi PU Patterson JR Peterson D Phillips EA Pivarski J Riley D Ryd A Sadoff AJ Schwarthoff H Shi X Stroiney S Sun WM Wilksen T Weinberger M Athar SB Avery P Breva-Newell L Patel R Potlia V Stoeck H Yelton J Rubin P Cawlfield C Eisenstein BI Karliner I Kim D Lowrey N 《Physical review letters》2006,96(9):092003
We determine the dielectron widths of the Gamma(1S), Gamma(2S), and Gamma(3S) resonances with better than 2% precision by integrating the cross section of e+e- -->Gamma over the e+e- center-of-mass energy. Using e+e- energy scans of the Gamma resonances at the Cornell Electron Storage Ring and measuring Gamma production with the CLEO detector, we find dielectron widths of 1.252+/-0.004(sigma(stat))+/-0.019(sigma(syst)) keV, 0.581+/-0.004+/-0.009 keV, and 0.413+/-0.004+/-0.006 keV for the Gamma(1S), Gamma(2S), and Gamma(3S), respectively. 相似文献
995.
J. Łukasik G. Auger M. L. Begemann-Blaich N. Bellaize R. Bittiger F. Bocage B. Borderie R. Bougault B. Bouriquet J. L. Charvet A. Chbihi R. Dayras D. Durand J. D. Frankland E. Galichet D. Gourio D. Guinet S. Hudan P. Lautesse F. Lavaud A. Le Fèvre R. Legrain O. Lopez U. Lynen W. F. J. Müller L. Nalpas H. Orth E. Plagnol E. Rosato A. Saija C. Schwarz C. Sfienti B. Tamain W. Trautmann A. Trzciński K. Turzó E. Vient M. Vigilante C. Volant B. Zwiegliński 《Acta Physica Hungarica A》2006,25(2-4):229-239
Directed and elliptic flow for the 197Au+197Au system at incident energies between 40 and 150 MeV per nucleon has been measured using the INDRA 4π multi-detector. For semi-central collisions, the excitation function of elliptic flow shows a transition from in-plane to out-of-plane emission at around 100 MeV per nucleon. The directed flow changes sign at a bombarding energy between 50 and 60 MeV per nucleon and remains negative at lower energies. Molecular dynamics calculations (CHIMERA) indicate sensitivity of the global squeeze-out transition on the σ NN and demonstrate the importance of angular momentum conservation in transport codes at low energies. 相似文献
996.
We report the formation of homogeneous and stable V2O3 nanocrystals, directly from V2O5 thin films, at 600 °C, as observed by using in situ electron microscopy experiments. Thermally-induced reduction of V2O5 thin films in vacuum is remarkably different when compared to reduction of V2O5 single crystals and results in the formation of nanophase V2O3. Thermally grown V2O3 nanocrystals exhibit hexagon or square shape and are stable at higher temperature as well as room temperature. The formation of stable nanocrystals through the reduction process in a non-chemical environment (vacuum) could provide a basis for understanding the complex processes of vanadium oxide phase transitions and for controlling the chemical processes to produce oxide nanocrystals. 相似文献
997.
U. Lucia G. Gervino 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(1-2):367-369
In this paper an analysis of the Stirling cycle in thermoeconomic
terms is developed using the entropy generation. In the thermoeconomic optimization of an
irreversible Stirling heat pump cycle the F function has been
introduced to evaluate the optimum for the higher and lower sources
temperature ratio in the cycle: this ratio represents the value which
optimizes the cycle itself. The variation of the function F is proportional to
the variation of the entropy generation, the maxima and minima of F has been evaluated in
a previous paper without giving the physical foundation of the method. We
investigate the groundwork of this approach: to study the
upper and lower limits of F function allows to determine the cycle stability and the
optimization conditions. The optimization consists in the best COP at
the least cost. The principle
of maximum variation for the entropy generation becomes the analytic
foundation of the optimization method in the thermoeconomic analysis
for an irreversible Stirling heat pump cycle. 相似文献
998.
Abazov VM Abbott B Abolins M Acharya BS Adams M Adams T Agelou M Ahn SH Ahsan M Alexeev GD Alkhazov G Alton A Alverson G Alves GA Anastasoaie M Andeen T Anderson S Andrieu B Anzelc MS Arnoud Y Arov M Askew A Asman B Jesus AC Atramentov O Autermann C Avila C Ay C Badaud F Baden A Bagby L Baldin B Bandurin DV Banerjee P Banerjee S Barberis E Bargassa P Baringer P Barnes C Barreto J Bartlett JF Bassler U Bauer D Bean A Begalli M Begel M Belanger-Champagne C Bellantoni L Bellavance A Benitez JA 《Physical review letters》2006,97(16):161802
We present a search for a neutral particle, pair produced in pp[over] collisions at sqrt[s]=1.96 TeV, which decays into two muons and lives long enough to travel at least 5 cm before decaying. The analysis uses approximately 380 pb(-1) of data recorded with the D0 detector. The background is estimated to be about one event. No candidates are observed, and limits are set on the pair-production cross section times branching fraction into dimuons + X for such particles. For a mass of 10 GeV and lifetime of 4x10(-11) s, we exclude values greater than 0.14 pb (95% C.L.). These results are used to limit the interpretation of NuTeV's excess of dimuon events. 相似文献
999.
U. Stolzenburg T. Lux 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,84(4):521-533
Processes of social opinion formation might be dominated by a set of closely connected
agents who constitute the cohesive ‘core’ of a network and have a higher influence on the
overall outcome of the process than those agents in the more sparsely connected
‘periphery’. Here we explore whether such a perspective could shed light on the dynamics
of a well known economic sentiment index. To this end, we hypothesize that the respondents
of the survey under investigation form a core-periphery network, and we identify those
agents that define the core (in a discrete setting) or the proximity of each agent to the
core (in a continuous setting). As it turns out, there is significant correlation between
the so identified cores of different survey questions. Both the discrete and the
continuous cores allow an almost perfect replication of the original series with a reduced
data set of core members or weighted entries according to core proximity. Using a monthly
time series on industrial production in Germany, we also compared experts’ predictions
with the real economic development. The core members identified in the discrete setting
showed significantly better prediction capabilities than those agents assigned to the
periphery of the network. 相似文献
1000.
U. P. Verma N. Devi S. Sharma P. Jensen 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,81(4):381-386
First-principles calculations based on the density functional theory are
performed to study the structural properties, spin-polarized electronic band
structures, density of states and magnetic properties of the zinc blende
In1−
x
Mn
x
Sb (x = 0.125, 0.25, 0.50, 0.75, 1.0).
The calculated lattice constants of In1−
x
Mn
x
Sb
obey the Vegard’s law with a marginal upward bowing. With the increase of Mn
concentration in In1−
x
Mn
x
Sb, a transition from
the semi-metallic to the half-metallic behavior happens such that the
majority-spin valence states crosses the Fermi level and the minority-spin
states have a gap at the Fermi level. A large exchange splitting
(∼ 4 eV) is observed between Mn 3d states of the majority-spins
and the minority-spins. The total magnetic moment of
In1−
x
Mn
x
Sb half-metallic ferromagnets per Mn
atom basis is 4μ
B. The total magnetic moment per Mn atom
indicate that Mn atoms act as acceptors in InSb and contribute to holes in
the lattice of InSb. Due to p-d hybridization, the free space charge of Mn
reduces that results a loss in its magnetic moment. The loss in the magnetic
moment of the Mn atoms is converted into a small local magnetic moments on
the In and Sb sites. 相似文献