Using the methods developed for different Bianchi class A cosmological models we treat the simplest Bianchi class B model, namely Bianchi type V. The future non-linear stability for solutions of the Einstein–Vlasov system is demonstrated and it is shown that these solutions are asymptotically stable to the Milne solution. Within the isotropic solutions of the Einstein–Vlasov system the spatially flat Friedmann solution is unstable within this class, and expanding models tend also to the Milne solution. 相似文献
Within nonrelativistic quantum mechanics, spatial cusps in initial wave functions can lead to nonanalytic behavior in time. We suggest a method for calculating the short-time behavior in such situations. For these cases, the density does not match its Taylor expansion in time, but the Runge-Gross proof of time-dependent density functional theory still holds, as it requires only the potential to be time analytic. 相似文献
A Zr-based metal-organic framework has been synthesized and employed as a catalyst for photochemical carbon dioxide reduction coupled with water oxidation. The catalyst shows significant carbon dioxide reduction property with concomitant water oxidation. The catalyst has broad visible light as well as UV light absorption property, which is further confirmed from electronic absorption spectroscopy. Formic acid was the only reduced product from carbon dioxide with a turn-over frequency (TOF) of 0.69 h−1 in addition to oxygen, which was produced with a TOF of 0.54 h−1. No external photosensitizer is used and the ligand itself acts as the light harvester. The efficient and selective photochemical carbon dioxide reduction to formic acid with concomitant water oxidation using Zr-based MOF as catalyst is thus demonstrated here. 相似文献
We report here a methodology for the construction of a conjugated cyanodiene synthon and the propensity of such synthons to participate in the olefin metathesis reaction. To this end, we have developed a strategy for the construction of the C11-C15 fragment of borrelidin and demonstrated the utility of the RCM reaction in the preparation of the final macrolide. To our knowledge, this is the first example of a RCM with a nitrile functionality on a diene. 相似文献
The optimal return function for a Borel measurable gambling problem with a bounded utility function was shown by Strauch (1967)
to be universally measurable when the problem is leavable in the sense that the gambler may terminate play at any time. The
same is shown here for the more general class of nonleavable problems.
Research supported by National Science Foundation Grant DMS-8801085. 相似文献
Can creation of matter be modelled? This communication proposes the idea of Time-Gel to address this question. Using existing framework of temporal dynamics of gelation, crystallization, criticality, time-crystal, and the idea of space-time symmetry breaking, with appropriate approximations, it is proposed Time-Gel concept can be used to this end. 相似文献
Distortion of pulses with pulse widths ranging from 0.1 to 1 ns propagating with carrier frequencies in the range 10–100 GHz through rain filled medium has been estimated considering the absorptive and dispersive effects produced by rain drops on the propagation of millimeter waves. It is found that the rain induced broadening or compression can be quite appreciable for very short pulses in the window region of millimeter wave band under intense and extensive raining conditions. 相似文献
Polymer nanocomposites containing different concentrations of Au nanoparticles have been investigated by small angle X‐ray scattering and electronic absorption spectroscopy. The variation in the surface plasmon resonance (SPR) band of Au nanoparticles with concentration is described by a scaling law. The variation in the plasmon band of ReO3 nanoparticles embedded in polymers also follows a similar scaling law.
Thermodynamic properties of the spinless Falicov-Kimball model are studied on a
triangular lattice using numerical diagonalization technique with Monte-Carlo simulation
algorithm. Discontinuous metal-insulator transition is observed at finite temperature.
Unlike the case of square lattice, here we observe that the finite temperature effect is
not able to smear out the discontinuous metal-insulator transition seen in the ground
state. Calculation of specific heat (Cv)
shows single and double peak structures for different values of parameters like on-site
correlation strength (U), f-electron energy
(Ef) and temperature. 相似文献