Low-frequency dynamic response of the bismuth strontium ferrite (Bi,Sr)FeO3−x

Broad-range measurements of the dynamic response of polycrystalline samples of the (Bi,Sr)FeO_3?x perovskite-like solid solution are performed over a frequency range from 10 Hz to 1 GHz at temperatures of 100–300 K for the first time. The colossal dielectric constant effect and the influence of electric contacts on the results of measurements are considered. It is shown that the frequency dependences of the permittivity and dynamic conductivity of (Bi,Sr)FeO_3?x samples can be described within the universal dielectric response model.     

One-loop counter-terms in theories regularized by higher covariant derivatives

In an arbitrary field-theory model regularized by the higher covariant derivative method, expressions for one-loop logarithmic divergences are shown to be consistent with the dimensional regularization; the precise form of the regularization terms is irrelevant. Therefore, we explicitly check the self-consistency of the higher derivatives method on the one-loop level. The calculation for the Yang-Mills theory is given. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 114, No. 1, pp. 137–147, January, 1998.     

In vitro study of glucose utilization and erythrocyte membrane penetrability

This study is devoted to the determination of the conditions of stable functioning of the self-regulation mechanism of nonspecific penetrability of erythrocyte membranes in blood in vivo. The kinetics of basic processes of erythrocyte energy metabolism after patient blood sampling was analyzed. The time dependences of the glucose concentration in blood plasma and the erythrocyte membrane penetrability for oxygen were experimentally measured. The increases in the average glucose utilization rate and the average membrane penetrability for oxygen were explained. It was shown that there exist osmotic variations in the blood plasma and erythrocyte cytoplasm in blood after its sampling. The possible cause of these variations was identified.     

Model-independent quantum approach for intense laser detachment of a weakly bound electron

We present a model-independent theory for laser detachment of a weakly bound electron having a nonzero angular momentum. Our treatment reduces to the well-known Keldysh result for tunnel ionization upon neglecting rescattering effects. Numerical results for the above-threshold detachment spectrum of a negative ion having an outer p electron show significant modification of the rescattering plateau as compared to that for an ion having an outer s electron.     

Experimental study of the stability and reflective properties of depleted uranium thin films at a wavelength of 4.5 nm

A technology of depleted uranium thin films, which can be used as high-reflectivity X-ray mirrors at a wavelength of 4.5 nm, is presented. The coefficient of X-ray reflection by these mirrors varies from 90 to 10% at grazing angles between 1° and 10°. The stability of the reflection coefficients for 200-Å-thick depleted uranium films covered by a protective carbon layer 100 and 200 Å in thickness and for 200-Å-thick uranium-nickel films with a nickel content of 9 and 23 wt % is studied. A high-reflectivity mirror is fabricated with the goal of increasing the X-ray radiation intensity in RKK-1-100 X-ray calibration equipment. Advice on fabrication of X-ray mirrors based on depleted uranium films is given.     

Reactive epitaxy of cobalt disilicide on Si(100)

The growth of cobalt disilicide on the Si(100) surface by reactive epitaxy at T=350°C was studied within the 10–40 ML cobalt coverage range. A new method of mapping the atomic structure of the surface layer by inelastically scattered medium-energy electrons was employed. The films thus formed were shown to consist of CoSi₂(221) grains of four azimuthal orientations turned by 90° with respect to one another. This domain structure originates from substrate surface faceting by (111) planes, a process occurring during silicide formation. B-oriented CoSi₂(111) layers grow epitaxially on (111) facets.     

The Doppler shift and anisotropy of quasimolecular X-rays emitted in Nb+Nb collisions at 67 MeV

The quasimolecularKX-ray spectrum obtained by bombarding Nb with 67 MeV Nb ions has been found to undergo a Doppler shift with an effective Doppler velocity equal to the mean center-of-mass velocity of the intermediate Nb+Nb molecule, corresponding to the projectile velocity. By applying Doppler shift corrections the intrinsic anisotropy of the quasimolecularKX-radiation is found.