Laser ultrasonic diagnostics of residual stress.

Ultrasonic NDE is one of the most promising methods for non-destructive diagnostics of residual stresses. However the relative change of sound velocity, which is directly proportional to applied stress, is extremely small. An initial stress of 100 MPa produces the result of deltaV/V approximately 10(-4).

Focused array transducer for two-dimensional optoacoustic tomography.

Optoacoustic (OA) imaging utilizes short laser pulses to create acoustic sources in tissue and time resolved detection of generated pressure profiles for image reconstruction. The ultrasonic transients provide information on the distribution of optical absorption coefficient that can be useful for early cancer diagnostics. In this work a new design of wide-band array transducer is developed and tested.

Exciton states of the antenna and energy trapping by the reaction center.

Forward and back energy transfer between antenna and RC in the photosynthetic apparatus of purple bacteria was studied taking into account the exciton states of the antenna. The exciton states were calculated for core antenna configuration in the form of a circular aggregate of N identical BChl molecules with the CN-symmetry. The influence of pigment inhomogeneity on the proposed exciton description of the antenna and its interaction with RC was investigated.