Anti-Stokes Luminescence in LiYF<Subscript>4</Subscript>:Ho<Superscript>3+</Superscript>, Yb<Superscript>3+</Superscript> Ceramics Excited at 1.93 μm

Conversion of IR radiation of a Tm:YAP laser with a wavelength of 1930 nm into visible light by ceramics of composition LiY_(1–x–y) Ho _x Yb _y , where х = 1–5 mol % and y = 0–15 mol %, is demonstrated. It is shown that the threshold power density of IR light visualization decreases with increasing concentration of Ho³⁺ ions, while additional doping of ceramic samples with Yb³⁺ ions changes the anti-Stokes luminescence spectrum. The threshold power density of visualization of the Tm:YAP laser radiation decreases with increasing concentration of holmium ions and is I_thr ≈ 0.8 W cm^–2 in the samples of composition LiYF₄:5%Ho³⁺–15%Yb³⁺.     

Variation of elastic characteristics of metastable austenite steel under cycling straining

We have analyzed the effect of elastoplastic cyclic straining on anisotropy of elastic properties of 08Kh18N10T metastable austenite steel. The possibility of determining the strain amplitude of the fatigue loading cycle by an acoustic method involving measuring the elastic characteristic of the material has been demonstrated. The resulting experimental dependences that can be used to estimate the number of cycles before failure using ultrasonic measurements have been revealed.     

Study of the Acoustoelastic Effect in an Anisotropic Plastically Deformed Material

Acoustical Physics - The paper discusses the dependence of shear elastic waves birefringence on applied mechanical stress and preliminary plastic deformation of a material. A technique involving...