We present a comprehensive analysis of a bright, long duration (T 90 ∼ 257 s) GRB 110205A at redshift z = 2.22. The optical prompt emission was detected by Swif t/UVOT, ROTSE-IIIb and BOOTES telescopes when the GRB was still radiating in the γ-ray band, with optical lightcurve showing correlation with γ-ray data. Nearly 200 s of observations were obtained simultaneously from optical, Xray to γ-ray (1 eV -5 MeV), which makes it one of the exceptional cases to study the broadband spectral energy distribution during the prompt emission phase. In particular, we clearly identify, for the first time, an interesting two-break energy spectrum, roughly consistent with the standard synchrotron emission model in the fast cooling regime. Shortly after prompt emission (∼ 1100 s), 14.0) optical emission hump with very steep rise (α ∼ 5.5) was observed which we interpret as the the reverse shock emission. It is the first time that the rising phase of a reverse shock component has been closely observed. The full optical and X-ray afterglow lightcurves can be interpreted within the standard reverse shock (RS) + forward shock (FS) model. In general, the high quality prompt and afterglow data allow us to apply the standard fireball model to extract valuable information including the radiation mechanism (synchrotron), radius of prompt emission (R GRB ∼ 3 × 10 13 cm), initial Lorentz factor of the outflow (Γ 0 ∼ 250), the composition of the ejecta (mildly magnetized), as well as the collimation angle and the total energy budget.
We report the study of the fluorescence switching properties of the conjugated copolymers containing triphenylamine, fluorene, benzo[2,1,3]thiadiazole, and cyclic urea moieties. The copolymers show excellent thermal stability and good solubility in polar organic solvents. While the electrofluorescent device (EFD) of P1 emits yellow light under UV excitation, fluorescence intensity is switched off upon electrochemical oxidation. In addition, the fluorescent behavior of the EFD of P1 can be reversibly switched between the non-fluorescent (oxidized) state and the fluorescent (neutral) state with a superb contrast ratio (I f /I f0 ) of 21.4. Furthermore, a white-light electrochemical fluorescence switching device is achieved by blending of P1 (yellow) with P2 (blue). Since the fluorescent conjugated polymers of P1 and P2 have their emission simultaneously quenched under the low working potential, the EFD could show a white-dark state of fluorescence with a high contrast ratio (I f /I f0 ) of 14.6.
The fluorescent behavior of the electrofluorochromic devices (Type I) of greenish-yellow emitting P1 and blue emitting P2 can be reversibly switched between the nonfluorescent (oxidized) state and the fluorescent (neutral) state with a superb on/off ratio of 23.8 and 21.9, respectively. Moreover, a tunable electrofluorochromic device (Type II) based on two P1 and P2 polymeric layers that are coated individually on two independent ITO electrodes shows switchable blue-white-(greenish-yellow) multifluorescence states.
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