Propagation Properties of Backward Lamb Waves in Plate Investigated by Dynamic Photoelastic Technique

The dynamic photoelastic technique is employed to visualize and quantify the propagation properties of backward Lamb waves in a plate. Higher energy leakage of second-order symmetric backward wave mode S2b in contrast to third-order anti-symmetric backward mode A3b is shown by the dispersion curve of a plate immersed in water, and then verified by experiments. To avoid the considerable high leakage, the plate is placed in air, both group and phase velocities of modes S2b and A3b in the glass plate are experimentally measured. In comparison with the theoretical values, less than 5% errors are found in experiments.

Comparison of choroidal thickness measured by two methods

AIM: To examine the profile of the choroidal thickness (CT) in healthy myopia subjects and emmetropic participants by Heidelberg Eye explore software and Image 3 software so as to compare the agreement and reproducibility of the two methods. METHODS: Thirty-six study participants (36 eyes) were enrolled in this research. The fovea and parafoveal region (the region of 6mm diameter of the fovea as center) of the images were selected by spectral domain optic coherence tomography (SD-OCT). The choroidal thickness was measured manually by the Heidelberg Eye explore software (version 5.3.3.0, Heidelberg Engineering) with a vertical line and the Image 3 software with a line vertical to the retinal pigment epithelial layer. The agreement and reproducibility of the two methods were described by the Bland-Altmann analysis. RESULTS: As compared with Heidelberg Eye explore software (39.9186), the repeatability coefficient is lower calculated by Image 3 software (27.3525). The Bland-Altmann analysis showed that the limits of 95% CI of agreement analysis is -18.437-63.949 mu m and the upper limits of the precision of the 95% CI of agreement is between 16.102 and 111.796 mu m and the lower limits is range from -66.29-21.41 mu m, which reflected a great variations of the difference. CONCLUSION: The repeatability and agreement of measurement implied by Image 3 software was better than the Heidelberg Eye explore software. The Image 3 software should be used for measuring the choroidal thickness in future study in China.

Bis(4,4′-dimethyl-2,2′-bipyridine)ruthenium(II) Complexes Containing 2-Arylimidazo-phenanthroline: Syntheses, Characterization and Third-order Nonlinear Optical Properties

Four novel mononuclear ruthenium(II) complexes [Ru-(dmb) 2L] 2+ [dmb=4,4′-dimethyl-2,2′-bipyridine, L=imid-azo-[4,5-f]phenanthroline (IP), 2-phenylimidazo-phenanthroline (PIP), 2-(4′-hydroxyphenyl)imidazo-phenanthroline (HOP), 2-(4′-dimethylami- nophenyl)imidazo-phenanthroline (DMNP)] were synthesized and characterized by ES-MS, 1H NMR, UV-vis and electrochemistry. The nonlinear optical properties of the ruthenium(II) complexes were investigated by Z-scan techniques with 12 ns laser pulse at 540 nm, and all of them exhibit both nonlinear optical (NLO) absorption and self-defocusing effect. The corresponding effective NLO susceptibility |χ 3| of the complexes is in the range of 2.68×10 -12-4.57×10 -12 esu.