A toy model for magnetized neutrino-dominated accretion flows

In this paper, we present a simplified model for a magnetized neutrino-dominated accretion flow (NDAF) in which the effect of black hole (BH) spin is taken into account by adopting a set of relativistic correction factors, and the magnetic field is parameterized as β, the ratio of the magnetic pressure to the total pressure. It is found that the disc properties are sensitive to the values of the BH spin and β, and more energy can be extracted from NDAFs by using a faster spin and lower β.

     

Energy dissipation and angular momentum transfer within a magnetically torqued accretion disc

We discuss transportation and redistribution of energy and angular momentum in the magnetic connection (MC) process and Blandford-Payne (BP) process. MC results in readjusting the interior viscous torque, and its effects are operative not only in but also beyond the MC region. The BP process is invoked to transfer the “excessive” angular momentum from an accretion disc. In addition, we derive a criterion for the interior viscous torque to resolve the puzzle of the overall equilibrium of angular momentum in disc accretion. It turns out that the efficiency of BP at extracting angular momentum and the intensity of the outflow are required to be greater than some critical values.

     

Synthesis, photophysical properties and TD-DFT calculation of four two-photon absorbing triphenylamine derivatives

In this study,linear absorption,single-photon excited fluorescence,fluorescence quantum yields,fluorescence lifetime and two-photon excited fluorescence of a series of triphenylamine derivatives (L1,L2,L3 and L4) have been measured.L1 and L3 are D--A type dyes,while L2 and L4 are D--D--A type dyes (D=donor,A=acceptor).The investigated compounds consist of triphenylamine-bearing donor-substituted and/or systematically extended-conjugated length,which are designed to gain insight into the effect of the ethoxyl unit and-linkage length on the linear and nonlinear optical properties.The influence of solvent polarity on the photophysical properties was investigated.Employing time-dependent density functional theory (TD-DFT) calculations,the structure-property relationships are discussed.