No abstract

A new method for correcting Mie scattering laser lidar short-range returns by virtue of Gaussian emission was described. Firstly, basing on the Gaussian character of laser beam, the lidar returns were corrected. Secondly, on the assumptionof an almost homogenous atmosphere, the corrected logarithmic range-adjusted power curve S(r) was fitted with conic section, then the corresponding influences of overlapping area were corrected. Some examples show that the corrected results are much closer to the real atmospheric conditions.

hThe microhardness, and tensile and fracture-toughness properties of drop-cast and directionally-solidified Cr-9.25 at.% (atomic percent) Ta alloys have been investigated.Directional solidification was found to soften the alloy, which could be related to the development of equilibrium and aligned microstructures. It was observed that the tensile properties of the Cr-Ta alloys at room and elevated temperatures could be improved by obtaining aligned microstructures. The directionally-solidified alloy also showed increased fracture toughness at room temperature. This trend is mainly associated with crack deflection and the formation of shear ribs in the samples with aligned microstructures. The sample with better-aligned lamellar exhibits greater fracture toughness.