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71.
C. Biely R. Hanel S. Thurner 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,67(3):285-289
We consider social systems in which agents are not only characterized by their states but also have the freedom to choose
their interaction partners to maximize their utility. We map such systems onto an Ising model in which spins are dynamically
coupled by links in a dynamical network. In this model there are two dynamical quantitieswhich arrange towards a minimum energy
state in the canonical framework:the spins, si, and the adjacency matrix elements, cij.The model is exactly solvable because microcanonical partition functions reduce to productsof binomial factors as a direct
consequence of the cij minimizing energy. We solve the system for finite sizes and for the two possible thermodynamic limits and discussthe phase
diagrams. 相似文献
72.
D. H. Zanette 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(2):269-273
We study the effects of noise on the collective dynamics of an ensemble of coupled phase oscillators whose natural frequencies
are all identical, but whose coupling strengths are not the same all over the ensemble. The intensity of noise can also be
heterogeneous, representing diversity in the individual responses to external fluctuations. We show that the desynchronization
transition induced by noise may be completely suppressed, even for arbitrarily large noise intensities, is the distribution
of coupling strengths decays slowly enough for large couplings. Equivalently, if the response to noise of a sufficiently large
fraction of the ensemble is weak enough, desynchronization cannot occur. The two effects combine with each other when the
response to noise and the coupling strength of each oscillator are correlated. This combination is quantitatively characterized
and illustrated with explicit examples. 相似文献
73.
The rapid dendritic growth of primary Ni3Sn phase in undercooled Ni-30.9%Sn-5%Ge alloy is investigated by using the glass fluxing technique. The dendritic growth velocity of Ni3Sn compound is measured as a function of undercooling, and a velocity of 2.47m/s is achieved at the maximum undercooling of 251 K (0.17TL). The addition of the Ge element reduces its growth velocity as compared with the binary Ni75Sn25 alloy. During rapid solidification, the Ni3Sn compound behaves like a normal solid solution and it displays a morphological transition of "coarse dendrite-equiaxed grain-vermicular structure" with the increase of undereooling. Significant solute trapping of Ge atoms occurs in the whole undercooling range. 相似文献
74.
A surface-enhanced Raman scattering sensor is developed by etching polymer optical fiber and coating with gold nanorods. The SERS sensing experiments are demonstrated with the analyte molecules of rhodamine 6G (R6G) at 514.5 nm laser excitation. The results show that a strong fiber Raman background scattering overwhelm the R6G molecule Raman signal in common optrod configuration, but a distinct R6G SERS spectrum with 9 order magnitude enhancement can be observed while directly focusing light on the probe. Further modeling indicates the enhancement is attributed to both nanorods local field and their coupling. 相似文献
75.
Shifeng Du Dongxiang Zhang Baohua Feng Jing-Yuan Zhang Jing-Cun Zang 《Optics Communications》2009,282(14):2960-12186
We report the generation of high-peak power multi-wavelength picosecond laser pulses using optical parametric amplification (OPA) in BBO seeded with pulses generated in a 5-mm length BaWO4 crystal by stimulated Raman scattering of 18-ps laser pulses at 532 nm. The maximum output energy of the amplified first-Stokes component at 559.7 nm was about 1.76 mJ. The corresponding maximum peak power, pulse duration and spectral line width were measured to be 117.3 MW, 15 ps and 18.0 cm−1, respectively. The multi-wavelength picosecond laser pulses were in the visible and near infrared ranges. Using this Raman-seeded OPA technique, the beam quality of the stimulated Raman scattering pulses can be improved. 相似文献
76.
Formation and evolution details of a blocky microstructure in AISI 304 stainless steel are studied by quenching method during directional solidification. Results show that a coupled growth microstructure, consisting of lathy ferrite and austenite, forms first from the melt. At solid-state transformation stage, most lathy ferrite disappears due to the phase transformation from ferrite to austenite. With further decreasing of the temperature, plenty of fine ferrite colonies occur in the original austenite region. The formation of the blocky ferrite indicates that reverse solid-state transformation from austenite to ferrite takes place. This transformation is due to the segregation and the instability of austenite during the growth of austenite under low cooling rate. The fine ferrite colonies transform into blocky ferrite at room temperature. TEM and EDS analyses were carried out to identify the phases and determine the phase composition, respectively. 相似文献
77.
Defect configurations of Ge-S binary glasses have been studied systemically by Raman scattering technique and positron annihilation lifetime spectra (PALS). The correlations between the positron lifetime data, structural features, and chemical compositions of Ge-S binary glasses have been established, and also the identification of open volume originated from coordination defects has been carried out. The cognizance of defect configuration will be very helpful to further understand the unique photosensitivity of chalcogenide glasses. 相似文献
78.
Cells of Voronoi diagrams in two dimensions are usually considered as having edges of zero width. However, this is not the case in several experimental situations in which the thickness of the edges of the cells is relatively large. In this paper, the concept of a thick Voronoi tessellation, that is with edges of non-zero width, is introduced and the statistics of cell areas, as thickness changes, are analyzed. 相似文献
79.
L. Natarajan 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(3):287-292
In this work, the multiplet splitting in terms of a spin-dependent model is analyzed. The spin-polarized and unpolarized single
configuration Dirac-Fock-Slater wavefunctions have been used in the evaluation of the total energies of highly ionized argon
with different L shell population The transition energies of hollow argon atom with initial configurations 1s
0
1/22s
m
1/22p
n
1/22p
l
3/2 with m = 0 to 2 and n + l varying from 6 to 1 are reported in this work. The calculations have been carried out by taking into account a relativistic
exchange potential in the Dirac-Slater potential. To account for the correlation effects, a correction term has also been
considered perturbatively. The present calculations show that the spin-polarized technique which is mainly applied to the
ground states of atoms may also be applied to atoms ionized in the inner shells with a good degree of accuracy.
Received 5 December 2000 and Received in final form 9 April 2001 相似文献
80.
S. A. Aseyev Yu. A. Kudryavtsev V. V. Petrunin 《Applied physics. B, Lasers and optics》1993,56(6):391-398
The main properties of longitudinal and transverse electric field ionizers for fast Rydberg atoms n=21–40 have been investigated. The dispersion and the background due to collisional processes between fast atoms and residual gas molecules have been measured and calculated. The kinetic energy spread of ions formed by field ionization of Rydberg atoms and their trajectories have been calculated. The potassium beam energy was 3.9 keV. 相似文献