We show that a periodic metal-metal multilayer nanostructure can serve as an efficient source of hard x-ray transition radiation. Our research effort is aimed at developing an x-ray source for medical applications, which is based on using low-energy relativistic electrons. The approach toward choosing radiator-spacer couples for the generation of hard x-ray resonant transition radiation by few-...

The cosmological QCD transition affects primordial density perturbations. If the QCD transition is first order, the sound speed vanishes during the transition and density perturbations fall freely. For scales below the Hubble radius at the transition the primordial Harrison-Zel’dovich spectrum of density fluctuations develops large peaks and dips. These peaks grow with wave number for both the ...

Starting with the well-established field equations that describe the radiation fields of lightning return strokes, the radiation fields generated when a charged particle is incident on or moving away from a perfectly conducting plane are obtained. These fields are known in the literature as transition radiation. The field equations derived thus are used to evaluate the energy, momentum and the ...

We formulate a gradual dynamical transition from a power-law inflation era with a scalar field to a radiation era with no scalar field including inhomogeneous perturbations to the FriedmannRobertson-Walker universe. We show that for the cosmic microwave background radiation fluctuations this is excellently approximated by a sudden transition, with application of the Lichnerowicz conditions, bot...

The effects of electromagnetic fields (EMFs) radiation at the frequency of 940 MHz on the structure and function of human adult and fetal hemoglobin (HbA and HbF) were studied. After extraction and purification of HbA and HbF, the oxygen absorption values for exposed and unexposed HbA and HbF to EMF were compared. The slope of oxygen absorption curve for exposed HbA was increased while that for...

Transition radiation is emitted when a relativistic charged particle crosses the boundary between two media of different dielectric properties. Radiation is also produced if the particle does not cross the discontinuity directly but passes it at such a close distance that its self-field is modified by the sudden change in the dielectric constant. In this case one speaks of diffraction radiation...