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Abstract We report a high-beam-quality long pulse 532 nm laser, which can operate in wide range of temperature. By using a master-oscillator power amplifier (MOPA) system and LBO extracavity-frequency-doubling, we achieved 532 nm laser with the maximum output power of 32 W, the pulse frequency of 12 kHz, and the pulse width 90.2 ns. In addition, the beam quality factors reached M2 x = 1. 31 , M2 y = 1. 36 , respectively. In order to get long pulse, apart from choosing suitable transmissivity of output coupler, we also spreaded the cavity length with a 4f imaging system. The laser was proved to be stable when the ambient temperature changed from −19 °C to 27 °C. Compared to other green lasers, this laser can be applied in Rayleigh beaconing because of its long pulse and wide range of working temperature. [ABSTRACT FROM AUTHOR]

Abstract: We present a semi-supervised time series classification method based on co-training which uses the hidden Markov model (HMM) and one nearest neighbor (1-NN) as two learners. For modeling time series effectively, the symbolization of time series is required and a new granulation-based symbolic representation method is proposed in this paper. First, a granule for each segment of time series is constructed, and then the segments are clustered by spectral clustering applied to the formed similarity matrix. Using four time series datasets from UCR Time Series Data Mining Archive, the experimental results show that proposed symbolic representation works successfully for HMM. Compared with the supervised method, the semi-supervised method can construct accurate classifiers with very little labeled data available. [Copyright &y& Elsevier]

Abstract: The reaction mechanism of atomic oxygen radical anion (O−) with pyridine (C5H5N) has been investigated at the G3MP2B3 level of theory. Three different entrance potential energy surfaces are explored, respectively, as atomic oxygen radical anion attacks γ-, β- and α-H atoms of pyridine. Possible thermodynamic product channels are examined subsequently. Based on the calculated G3MP2B3 energies and optimized geometries of all species for the title reaction, it has been demonstrated that the oxide anion formation channel is dominant, and the C5H3N− +H2O channel is also favorable in thermodynamics, whereas the H-abstraction and H+-abstraction channels are inaccessible at room temperature. The present conclusions are consistent qualitatively with the previous experimental results. The secondary reactions of the anionic products are expected to be responsible for the contradiction of branching ratios between present calculation and previous experiments. [Copyright &y& Elsevier]

Abstract: The static and dynamic reaction pathways involved in the reaction between O− and CH3F have been investigated. A special attention has been paid to the SN2 reaction channel, that the intrinsic reaction coordinate (IRC) calculation, one-dimensional relaxed potential energy scan, and Born–Oppenheimer molecular dynamics (BOMD) simulations have been performed, respectively. Both the forward IRC calculation and the relaxed potential energy scan from the [O⋯CH3⋯F]− barrier show that the static reaction products are HF and CH2O−. However, the BOMD simulations initiated at this SN2 barrier reveal two major dynamic reaction processes, which correspond to the products of HF+CH2O− and the SN2 reaction products of F− +CH3O, respectively. Although only 104 dynamic trajectories are calculated, the HF+CH2O− production channel seems to be more dominant than the SN2 pathway. However, the electron detachment process of CH2O− potentially causes its vanishing in experiments as an anionic product. [Copyright &y& Elsevier]

• Tm:YAG and Ho:YAP integrated gain medium is proposed for a diode-pumped 2.1 μm laser. • The maximum output power of the integrated Tm:YAG/Ho:YAP laser is 5.06 W at 2130 nm. • The results verify the integration of heterogenous Tm-doped and Ho-doped crystals. We demonstrate a compact diode-pumped Ho laser via integrating heterogenous Tm-doped and Ho-doped gain media into a single bulk gain medium for the first time. After achieving efficient Ho laser operation from the Tm:YAG intra-cavity pumped Ho:YAP scheme, with an maximum output power of 6.6 W, the integrated Tm:YAG/Ho:YAP laser was realized with a maximum output power of 5.1 W at 2129.7 nm, corresponding to a slope efficiency of 25.4% and optical conversion efficiency of 21.6% by considering the absorbed diode pump power. [ABSTRACT FROM AUTHOR]