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The optical constants of rhodamine 6G dissolved in methanol and of a solid rhodamine 6G film are determined. The concentration of the solutions is varied between 10 _ 5 and 0.66 mol/Y. Deviations from Beer's law at high concentrations are found. They are thought to be due to the mutual interaction of neighbouring molecules. The absorption behaviour of rhodamine 6G in methanol is compared with the absorption behaviour of rhodamine 6G in water.

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By use of a laser diode as a pump source, a self-Q-switched laser from a Cr, Nd:YAG crystal is demonstrated. The output Q-switched traces are very stable, the threshold pump power is 3.5 W, the pulse duration is 50 ns, and the slope efficiency is as high as 20%. In addition, the pulse width remains constant while the pulse repetition rate varies with pump power.

A LiNbO3 crystal with periodic laminar ferroelectric domain structures (460 domains) was used to generate 430 and 435 nm radiation by quasi-phase-matched frequency doubling at room temperature. Blue light output of 0.2 μJ energy was measured for input energy 5 μJ of fundamental wave in pulse operation.

The problem of a piezoceramic hollow sphere is investigated analytically based on the 3D equations of piezoelasticity. The functionally graded property of the material along the radial direction can be taken arbitrarily in the paper. Displacement and stress functions are introduced, and two independent state equations with variable coefficients are derived. By employing the laminate model, the two state equations are transformed into ones with constant variables from which the state variable solution is easily obtained. Two linear relationships between the state variables at the inner and outer spherical surfaces are established. Numerical calculations are performed for different boundary conditions imposed on the spherical surfaces.

An experimental arrangement is described for determination of refractive indices n and extinction coefficients k of strongly absorbing liquids and solids over a wide spectral region. The reflectivity of parallel polarized light vs angle of incidence is measured, and the optical constants are calculated from the minimum parallel reflectivity and the corresponding Brewster angle. The accuracy of n and k determination is analyzed. The refractive indices and extinction coefficients of 0.4-M rhodamine 6G in methanol are presented around the St absorption band.

The prediction information has effects on the emergency prevention and advanced control in various complex systems. There are obvious nonlinear, nonstationary, and complicated characteristics in the time series. Moreover, multiple variables in the time-series impact on each other to make the prediction more difficult. Then, a solution of time-series prediction for the multivariate was explored in this paper. Firstly, a compound neural network framework was designed with the primary and auxiliary networks. The framework attempted to extract the change features of the time series as well as the interactive relation of multiple related variables. Secondly, the structures of the primary and auxiliary networks were studied based on the nonlinear autoregressive model. The learning method was also introduced to obtain the available models. Thirdly, the prediction algorithm was concluded for the time series with multiple variables. Finally, the experiments on environment-monitoring data were conducted to verify the methods. The results prove that the proposed method can obtain the accurate prediction value in the short term.