Renormalization equations in gravitational theory with higher derivatives

The structure of renormalization equations in gravitational theories with higher derivatives is considered. The gauge dependence of invariant divergences of the effective action is found to be nontrivial. The external source technique is used to construct a consistent Green's function renormalization. One- and two-loop divergences of the effective action are explicitly calculated for an arbitrary parametrization and gauge. These calculations fit the general structure of the obtained renormalization equations. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 121, No. 3, pp. 387–411, December, 1999.     

One-loop effective action for an arbitrary theory

Using the diagram technique, we obtain formulas for the divergent part of the one-loop effective action for an arbitrary minimal operator in four-dimensional curved space and for an arbitrary nonminimal operator in flat space.Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 109, No. 2, pp. 215–231, November, 1996.     

Effect of focusing of primary electrons on their reflection from a crystal and on the associated Auger emission

The orientational dependence for different groups of secondary electrons — quasi-elastically scattered, inelastically reflected with excitation of a plasmon and with ionization of the core level M _4.5, and the Auger electrons M _4.5 VV — are measured in the primary electron energy range 0.6–1.5 keV. The data are obtained for a Nb (100) single crystal by varying the azimuthal angle of incidence of the primary beam, with complete collection of secondaries. A relationship is established between the processes of focusing and defocusing of the electrons that have penetrated into the crystal in the 〈110〉 and 〈133〉 directions, which differ substantially in the atomic packing density. Specific details of the Auger orientation effect, due to the focusinginduced variation of the flux density of the reflected electrons, are identified and explained. The contributions, both of anisotropy of ionization of the core level and of variation of the backscattering intensity, to the angular dependence of Auger emission and reflection with ionization loss are estimated. The possibilities of using such orientational dependences for an element-sensitive analysis of the local atomic structure of surfaces are assessed. Zh. Tekh. Fiz. 67, 117–123 (August 1997)     

Magnetic properties of multiwall carbon nanotubes and astralenes in strong electric fields

The force interaction between anode and cathode in the process of field-emission current extraction from cathodes based on carbon nanoclusters—carbon nanotubes and astralenes—has been investigated. The measured forces are linear functions of the field-emission current and significantly exceed the forces conditioned by the electrostatic nature of interaction. The observed effect is explained within the framework of a model that suggests the formation of magnetic nanoclusters in the cathode and the emission of polarized electrons.     

Finite temperature contributions to the renormalized energy-momentum tensor for an arbitrary curved space-time

The finite temperature contributions to the effective Lagrangian and energy-momentum tensor in the cases of scalar and spinor fields are evaluated by means of the Green's function method. The results are obtained in an arbitrary curved space-time by adiabatic expansions of the Green's functions.We would like to thank professor D. Ivanenko for support of our work and many stimulating discussions.     

Ferromagnetic alignment of iron nanostructures on the silicon surface

The phase composition, electronic structure, and magnetic properties of nanostructures formed upon deposition of iron on the surface of the Si(556) vicinal face coated by a submonolayer silver film with a √3×√3-Ag structure have been studied using high-energy-resolution photoelectron spectroscopy and analysis of magnetic linear dichroism in photoemission of Fe 3p electrons. The effective thickness of the deposited iron layer is varied from 1 to 25 ?. It has been shown that a 1- to 2-? Fe coverage leads to the formation of a metastable iron silicide thin layer with a CsCl-type structure on the surface of the sample. A further deposition of Fe (up to ≈7 ?) brings about the formation of chains consisting of nonmagnetic islands of the Fe—Si solid solution on this layer, which are oriented along the steps of the substrate. A ferromagnetic alignment of the system along the surface of the sample appears only at coverages of approximately 10 ?, when larger (≈100 nm) iron islands start to grow on the solid solution layer.     

Dependence of the atomic structure and surface relief of platinum foils on the annealing and rolling conditions

The effect of cold rolling, polishing, and thermal annealing conditions on the atomic structure and surface geometry of platinum foils has been studied. The surface morphology has been analyzed using low-energy electron diffraction, atomic force microscopy, and scanning tunneling microscopy. The chemical composition of the surface has been evaluated by Auger electron spectroscopy. It has been demonstrated that a variation in the conditions used for the preparation of the samples makes it possible to produce surfaces with different degrees of perfection from atomically smooth to rippled, fractal, and diffraction-disordered surfaces.     

Elliptic and circular dichroism effects in two-photon double ionization of atoms

An ab initio parametrization of the two-photon double ionization amplitude from an s2 subshell of an atom in a 1S state is presented and used to predict two light polarization effects on photoelectron angular distributions that do not exist in single-photon double ionization: (i) elliptic dichroism and (ii) circular dichroism at equal energy sharing. Estimates for He show large magnitudes for these effects, which provide a means for polarization control of double ionization by vacuum ultraviolet light.     

Irreversible change in erythrocyte metabolism as a main cause of patient stress after banked donor blood transfusion

This paper is devoted to the study of causes of the stress (i.e., patient health deterioration) occurring after transfusion of banked donor blood stored more than one day. The kinetics of metabolic processes of erythrocytes in vivo and during blood storage was (graphically) analyzed. Main causes of the stress were determined.