Experimental study of regions of reversed magnetization in an amorphous layer of Co70Fe5Si10B15

The characteristics of the distribution of magnetization and remagnetization of microsections of the surface in the amorphous alloy Co₇₀Fe₅Si₁₀B₁₅, prepared in the form of thin ribbons, were studied by the magnetooptical method. It was found that the magnetization I on the surface of the amorphous ribbon studied was strongly nonuniform. It was established that heat treatment (HT) of the sample leads to the appearance of regions of reversed magnetization in the surface layer of the ribbon, while thermomagnetic annealing reduces the nonuniformity of I. The conservation of the transverse component in the HT sample in fields where the magnitude of the component of magnetization parallel to the length of the ribbon remains virtually unchanged suggested that a domain structure of the magnetization ripple type, owing to the strong microdispersion of the magnetic anisotropy, is realized in this sample.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 89–94, March, 1988.     

On a method of constructing the solutions of boundary-value problems of the theory of bendings of surfaces of positive curvature

A new method is proposed for constructing the solutions of boundary-value problems of Riemann-Hilbert type for noncanonical linear and quasilinear first-order elliptic systems in a simply connected bounded region of the plane. For a linear boundary condition we obtain complete results; for a nonlinear boundary condition we study the solvability in a neighborhood of zero. Applications are given to the problem of isometric transformations of a surface diffeomorphic to the disk and having positive curvature all the way to the boundary under prescribed boundary conditions.Translated from Ukrainskií Geometricheskií Sbornik, Issue 29, 1986, pp. 56–82.     

Nonclassical states generated via four-wave mixing

The nonclassical properties of quantum fields generated by four- or three-wave mixing are investigated on the basis of assumptions of two-photon coherent (squeezed) input states and the approximation of strong pumping. The influence of losses is shown supposing the model of mutually independent phonon reservoirs. The possibility of producing squeezed and sub-Poisson light outputs is demonstrated in single or superposed modes using computer solutions.The author wishes to acknowledge helpful discussions with Dr. J. Peina and Dr. M. Kárská.     

Effect of multijunction grill length on its lower hybrid current drive efficiency

The distance between the junction of subsidiary waveguides in the main waveguide and the grill mouth has an important influence upon the spectrum of radiated waves, the total reflection coefficient, the power distribution among the separate waveguides and the actual phases of incident waves. This effect is nearly as important as that of the phase shift between the adjacent waveguides and it is necessary to carry out optimization with respect to this parameter in the grill design.     

Optical constants of titanium and silicon dioxide films

In this paper a study of optical constants of titanium and silicon dioxide films prepared in Balzers BAK 600 and BA 510 conventional high-vacuum apparatus is described. Both the dispersion and the geometrical thickness were determined from normal reflectance spectrum by adapted general algorithm of the statistical interpretation of measured data. The dependence of optical constants on oxygen pressure for both materials and the evaporation rate dependence for titanium dioxide were obtained. The time changes of these constants were also measured.     

Low energy restrictions for a flipped left-right symmetric model

I consider some low energy restrictions for a “flipped” left-right symmetric model containing exotic fermions ofE ₆ and a right-handedW-boson, all with oddR-parity. The new interactions due toW _R-exchange have no significant impact on rare kaon decays, because theW _R does not couple tod,s,b quarks. On the other hand,W _R exchanges might induce rare processes like \(D - \bar D\) mixing, \(D^0 \to \mu \bar \mu ,D^0 \to \mu \bar e,\mu \to e\gamma ,\mu \to 3e\) , and μN→eN. It turns out that the strongest bound is obtained from \(D - \bar D\) mixing. With reasonable extra assumptions, it is found that the exotic right-handed W-boson is likely to be heavier than 500 to 1500 GeV.     

The effective action of a spin 1/2 field in the background of a nontopological soliton

We generalize a new method of calculating the effective action for fields in a spherically symmetric background to the case of a spin 1/2 field whose mass is a function ofr=|x|, as it is the case in the nontopological soliton model of Friedberg and Lee. The quantum corrections to the soliton energy are sizeable, of the same order as the bound state energies that stabilize the soliton.     

Investigation of oxyhemoglobin in leukaemic patients

Oxyhemoglobin from human normal adults and from leukaemic patients has been studied by Mössbauer spectroscopy to investigate the possibility to distinguish, through differences in the Fe²⁺ electronic structure, normals and leukaemic patients.     

High dose iron implantation into silicon and metals

High dose implantations of Fe into metals and semiconductors have been performed with beam energies up to 1 MeV at the UNILAC-injector at GSI. Unusual high concentrations of 70 atomic % for Si and 20 atomic % for Cu have been obtained, with doses of 10¹⁸ Fe/cm² in the case of Si and several 10¹⁷ Fe/cm² in the case of Cu. For Si the thickness of the layers were determined by Rutherford backscattering to be 4500 Å. These results are consistent with calculations, which show that these high concentrations are due to the reduction of the sputter yield at the relative high particle energies. Samples have been characterized using several complementary methods (Mössbauer Spectroscopy (MS), Rutherford Backscattering Spectroscopy (RBS), Auger electron Spectroscopy (AES). Scanning Electron Microscopy (SEM), X-ray diffraction (XRD)).     

Results on the Generic Kurepa Hypothesis

K.J. Devlin has extended Jensen's construction of a model ofZFC andCH without Souslin trees to a model without Kurepa trees either. We modify the construction again to obtain a model with these properties, but in addition, without Kurepa trees inccc-generic extensions. We use a partially defined -sequence, given by a fine structure lemma. We also show that the usual collapse of Mahlo to ₂ will give a model without Kurepa trees not only in the model itself, but also inccc-extensions.