[Muscular strength development by electromagnetic stimulation].

A new tool for muscular strength development by electromagnetic stimulation (MS) of muscular during voluntary contraction has been described. 18 healthy subjects (men) took part in the research. They were devided into two groups--control (CG) and experimental (EG). Subjects of CG and EG have equal muscular strength parameters. M. gastrocnemius of subjects in EG was exposed to MS (1.8 T, 5 Hz) during training exercises (plantar foot flection). The subjects of CG did not receive MS. The torque of plantar foot flection of EG subjects increased significantly (24%) during 10 days training. The torque of plantar foot flection of CG subjects did not change significantly. We hypothesize increasing of muscular strength of EG subjects was result of high-threshold motor units activation under MS.

Ultrafast time-to-space conversion of phase by the method of spectral nonlinear optics.

We propose a method for direct conversion of an ultrashort pulse into a monochromatic beam whose wave front either repeats or is related to the phase structure of the pulse or its spectrum. This can be done by sum-frequency generation of the spectrally resolved pulses. Experimentally, we projected two spectra of the same chirped pulse onto the nonlinear crystal so that the dispersions were opposite. After sum-frequency generation, a converging or diverging monochromatic beam was formed that was the analog of the pulse spectrum. We could determine the chirp value by the measurement of the wave-front radius.