Shear deformation of bridgmanite and magnesiowüstite aggregates at lower mantle conditions.

Rheological properties of the lower mantle have strong influence on the dynamics and evolution of Earth. By using the improved methods of quantitative deformation experiments at high pressures and temperatures, we deformed a mixture of bridgmanite and magnesiowüstite under the shallow lower mantle conditions. We conducted experiments up to about 100% strain at a strain rate of about 3 × 10(-5) second(-1).

Mapping temperatures and temperature gradients during flash heating in a diamond-anvil cell.

Here, we couple two-dimensional, 4-color multi-wavelength imaging radiometry with laser flash heating to determine temperature profiles and melting temperatures under high pressures in a diamond-anvil cell. This technique combines the attributes of flash heating (e.g.

Angular spectrum method and ray algorithm for the acoustic field of a focusing transducer in an anisotropic solid.

The angular spectrum method is applied to calculating the acoustic field of a liquid-coupled focusing transducer in an anisotropic slab-shaped solid with surfaces normal to the axis of the transducer. The stationary phase approximation (SPA) is used to determine the dominant contributions to this field and calculate the echo signals produced by waves that have been reflected off the rear surface of the solid. The dominant features of this field and of the echoes are reproduced well by a hybrid ray method devised to simulate the finite point-spread function of the lens.