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Dy3+-doped and Dy3+:Yb3+-codoped oxyfluoride glass ceramics have been prepared by high-temperature solid phase sintering method. The micrographs of scanning electron microscope show that a lot of nanorods are formed on the surface of Dy3+:Yb3+-codoped sample. The excitation spectra and emission spectra are measured, respectively, and intense photoluminescence peaks at 482 and 575 nm corresponding to the transitions of Dy3+ ions are found in single-doped samples under 388-nm excitation. For Dy3+:Yb3+-codoped oxyfluoride glass ceramics, the intensities at blue and green bands become weaker whereas the intensity at 695 nm gets stronger. The indirect sensitization is detailedly discussed and Commission Internationale de l′E-clairage chromaticity coordinates exhibit that two kinds of oxyfluoride glass ceramics are available candidates for the solid-state white light emission.

In this work, we present timed automata as a natural tool for posing and solving time varying postman problems. We show that these problems can be reduced to the problem of finding the shortest runs in our Timed Automata System TAS model. The problem can then be solved by incorporating the reachability analysis RA algorithm into a binary search framework. However, the scale of the TAS model is too large to adapt the RA algorithm embedded in the UppAal. Thus, we propose a composition strategy to transform the current TAS model into a Generalized Timed Automaton GTA model, such that the number of timed automata in our model decreases from to . Computational results show that the GTA model can solve small-sized instances optimally and that it can obtain a better optimality gap than those obtained by the cutting plane algorithm.