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164.
Georg Süssmann 《Zeitschrift für Physik A Hadrons and Nuclei》1975,274(2):145-159
The parameters proposed by W. D. Myers to describe the radial shape dependence of the nuclear surface are shown to be as useful as they are natural. For spherical nuclei, the central radiusC, the charge radiusR, the quadratic radiusQ are redefined, and it is shown how they are interrelated by Myers' surface widthb, flair γ3, crookedness γ4, and the higher shape parameter γ5. All these quantities are calculated for some special charge distribution functions. (For symmetric distributions, possessing a symmetry center atC, the odd surface momentsb 3γ3 andb 5γ5 vanish.) The connection of the surface moments Гμ =b μ γ μ with the volume momentsF k that have been extracted by K. W. Ford and J. G. Wills from muonic atoms, is indicated. 相似文献
165.
Christine?Hartwig Andres?Veske Sarka?Krejcova Georg?Rosenberger Ulrich?FinckhEmail author 《BMC neuroscience》2005,6(1):53
Background
Plexins, known to date as receptors of semaphorins, are implicated in semaphorin-mediated axon repulsion and growth cone collapse. However, subtype-specific functions of the majority of the nine members of the mammalian plexin family are largely unknown. In order to investigate functional properties of B-plexins, we analyzed the expression of human and murine plexin B3 and expressed full-length human plexins B2 (B2) and B3 (B3) in NIH-3T3 cells. 相似文献166.
We study the resistivity of a quantum wire caused by backscattering of electrons by acoustic phonons. In the presence of Coulomb interactions, backscattering is strongly enhanced at low temperatures due to Luttinger liquid effects. Information about the strength of the interactions can be obtained from a measurement of the temperature dependence of the resistivity. 相似文献
167.
We examine the contribution of pairing fluctuations to the superfluid order parameter for harmonically trapped atomic Fermi gases in the BCS regime. In the limit of small systems we consider, both analytically and numerically, their space and temperature dependence. We predict a parity effect, i.e., that pairing fluctuations show a maximum or a minimum at the center of the trap, depending on the value of the last occupied shell being even or odd. We propose to detect pairing fluctuations by measuring the density-density correlation function after a ballistic expansion of the gas. 相似文献
168.
We introduce an extension of the usual replicator dynamics to adaptive learning rates. We show that a population with a dynamic learning rate can gain an increased average payoff in transient phases and can also exploit external noise, leading the system away from the Nash equilibrium, in a resonancelike fashion. The payoff versus noise curve resembles the signal to noise ratio curve in stochastic resonance. Seen in this broad context, we introduce another mechanism that exploits fluctuations in order to improve properties of the system. Such a mechanism could be of particular interest in economic systems. 相似文献
169.
The phonon-induced dephasing dynamics in optically excited semiconductor quantum dots is studied within the frameworks of the independent boson model and optimal control. We show that appropriate tailoring of laser pulses allow complete control of the optical excitation despite the phonon dephasing, a finding in marked contrast to other environment couplings. 相似文献
170.
Pickering AL Seeber G Long DL Cronin L 《Chemical communications (Cambridge, England)》2004,(2):136-137
Isolated polymeric Ag(I) coordination tubes are self-assembled from the rigid triamino ligands cis,cis-1,3,5-triaminocyclohexane (cis-tach) and cis,trans-1,3,5-triaminocyclohexane (trans-tach), forming two topologically equivalent framework motifs. 相似文献