Coherence of synchrotron radiation

Gal'tsov et al. [Vestn. Mosk. Gos. Univ., Fiz., Astron.,14, No. 5, 614 (1973)] studied the radiation spectrum of N equally spaced charges moving along a circle. In particular, it was shown that as N the intensity of the radiation from the system of charges vanishes. The present study will consider the radiation spectrum of N charges moving along an arbitrary closed curve, randomly distributed in the vicinity of equally spaced points. The coherency factor will be found for the assumption that: a) the distributions of individual charges are not intercorrelated; b) the charge distribution is such that in the vicinity of a given point only one charge is found. It will be shown that as N the radiation intensity tends to a finite limit.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 8–11, March, 1988.     

Chlorokomplexe von Cu2+ und Ni2+ in Dimethylformamid

Zusammenfassung Durch spektrophotometrische Messungen in Dimethylformamid (DMF) werden die Koordinationsformen [CuCl]⁺ und [CuCl₃]^– sowie [NiCl]⁺, [NiCl₃]^– und [NiCl₄]^2– nachgewiesen. Bei Nickel(II)-chlorid und Kupfer(II)-chlorid wird Autokomplexbildung diskutiert. Die Solvate [Cu(DMF)₄] (ClO₄)₂ und [Ni(DMF)₆] (ClO₄)₂ werden isoliert.Im Zuge der Untersuchungen über Chlorokomplexe von Ionen der Übergangsmetalle^{1, 2} in nichtwäßrigen Lösungsmitteln wurden die Spektren der Lösungen von Kupfer(II)- und Nikkel(II)-perchlorat inDMF in Gegenwart verschiedener Mengen Tetraäthylammoniumchlorid aufgenommen.Mit 5 Abbildungen     

Qualitative analysis of finite-gap solutions of the KgΦ equation by the automorphic approach

By the automorphic approach and the use of computer graphics, we carry out a qualitative analysis of finite-gap periodic solutions of the Kg equation. Graphs are constructed for multiphase solutions.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 165, pp. 31–41, 1987.     

Addendum to the paper “on a theorem of Miranda”

An existence theorem is proved for closed convex surfaces whose principal radii of curvature regarded as functions of the unit normal vectorn satisfy the equation

The minimum area of a surface with prescribed boundary contour in a pseudoeuclidean space

LetE ^{n, k} be a pseudoeuclidean space with linear elementdx ₁ ² ++dx _n–k ² –dx _n–k ^+1/2 ––dx _n ² . The area of a smooth two-dimensional surface inE ^{n, k} is defined by , whereE, F, andG are the coefficients of the first fundamental form of the surface andD is the region of variation of the parametersu andv. The following theorem is proved: LetL be a piecewise smooth closed curve inE ^{n, k} (1kn–1). Then there exists a two-dimensional piecewise smooth surface of arbitrarily small area bounded by the curveL. 3 figures.Translated from Ukrainskií Geometricheskií Sbornik, No. 30, 1987, pp. 18–22.     

On the reductibility of the general existence problem for closed convex surfaces to Miranda's equation

It is proved that the solution of the general existence problem for closed convex surfaces with prescribed local propertiesf(R ₁ R ₂,R ₁+R ₂,n)=(n) can be obtained as the solution of Miranda's equationR ₁ R ₂+(f)+cn=((n),(n)) with right-hand side depending on the unknown surface under the hypothesis that the latter satisfies the closure condition , where is the unit sphere andd is its element of area.Translated from Ukrainskií Geometricheskií Sbornik, Issue 29, 1986, pp. 103–112.     

Theory of surface spin-exchange recombination of spin-polarized hydrogen

Calculations of the two-atom surface recombination rate for spinpolarized atomic hydrogen are carried out. Both the plane-wave Born approximation (PWBA) and the -dimensional distorted-wave model are employed. The field dependence forB=4 to 10 Tesla, and the temperature dependence for 0.2<T<1 K are examined for systems initially consisting of equal numbers ofa- andb-state atoms. The rates are analyzed with respect to para- and ortho-H₂ production, and to recombination to various vibrational and rotational states of H₂. The PWBA gives reasonable agreement with experiment with respect to the field-dependence and ortho-para production, but predicts an overall rate a factor of 40 above experiment. The -dimensional model underestimates the rate by a factor of 10³ and yields poorer agreement with experiment than the PWBA for the field-dependence and ortho-para production ratio. These results point out the need for a proper many-body treatment.     

Threshold anomaly in doubletn-d scattering

The behaviour of the doubletn-d scattering phase shift ₂(k) at energies close to the three-particle threshold is studied analytically and numerically. The scattering parameters possess an anomaly associated with the low energy of the singletN-N virtual state. The anomaly manifests itself both as a bend in the energy dependence of the functionk cot(Re ₂) in the range around 0.5 MeV and in the nonstandard behaviour of the break-up cross section near the threshold.     

Bound on the Higgs boson mass with no zero-charge behaviour in a magnetic field

The upper boundm<280 GeV/c² on the Higgs boson mass is obtained by considering the requirement that the electroweak theory must be consistent in a magnetic fieldH. The restriction emerges naturally by studying the effective potential in a magnetic field as a function of mass, and the values ofm when there is no zero-charge, in the fieldsH～H ₀=M _w ² /e are obtained.     

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.