Some problems with determination of alpha-active nuclides during decommissioning of nuclear power plant A-1

The first step in decommissioning of NPP is connected with defueling and successful disposal of liquid radioactive wastes (LRW), both from previous production and all work connected with this step. These require precise knowledge about the concentration of radioactive nuclides presented, especially alpha-emitters in all material fluxes arising in sich work (namely shut-down after some accident). This paper reports, results of the determination of U, Pu, Am and Cm by means of both the commonly used and the newly developed radiochemical procedures in various types of materials, e.g., LRW, aerosol filters, ashes resulted from incineration technology, metal surfaces, decontamination solutions etc.     

Determination of interdiffusion coefficients in the Co-Ni system with the use of spline functions

The interdiffusion of Co-Ni has been investigated at the temperature 1150 ?C. The concentration dependence curvesc(x, t) obtained with the aid of an JXA-3A electron microprobe were evaluated with the use of smoothing cubic spline by means of the Boltzmann-Matano method. The results are interpreted in terms of Co-Ni equilibrium diagram and compared with the results of other authors. On the basis of this comparison a conclusion was drawn which interdiffusion coefficient values can be taken for most realistic in the given system at 1150 ?C. In the Appendix of this paper a program in the USASI-STANDARD FORTRAN language, generally applicable to the calculations of interdiffusion coefficients with the use of cubic spline, is given.     

On an inverse problem in quantum statistical physics

Restoration of the full probability distribution by means of its asymptotics is considered. In the present contribution such cases are discussed where information about the asymptotics can be deduced from statistical properties of real physical systems represented, e.g., by light beams in the case of the photoproduction of electrons in the field of quantum optics or by (charged) secondaries produced by collisions observed in the field of high energy physics. Arbitrarily many modes with superposition of stochastic and coherent components are taken into account including also the case of pure coherent fields. The difference of the last case compared with the superposition alone is emphasized. To solve the corresponding inverse problems the Poisson transform is applied. Scaling properties of asymptotic probability distributions and some open problems are mentioned too.     

Die Struktur der oberflächlichen Abschlussbezirke in den Ebenen (100) in Eisen. Die Bäumchenstruktur

Zusammenfassung Auf Grund der Gesamtenergiebilanz wird die Bäumchenstruktur erklärt und werden die Abmessungen dieser Abschlussbezirke berechnet. Es wird die Abhängigkeit vom Neigungswinkel der Beobachtungsebene und von der Grösse der Abschlussbezirke und damit auch von der Kristallgrösse ermittelt. Für jede Abmessung der Grundbezirke existiert auch ein maximaler Neigungswinkel der Beobachtungsebene, bis zu welchem die Bäumchenstruktur stabil ist. Diese Neigung verringert sich mit dem Anwachsen der Bezirksabmessung.     

On embedding expanders into ℓ p spaces

In this note we show that the minimum distortion required to embed alln-point metric spaces into the Banach space ℓ _p is between (c ₁/p) logn and (c ₂/p) logn, wherec ₂>c ₁>0 are absolute constants and 1≤p<logn. The lower bound is obtained by a generalization of a method of Linial et al. [LLR95], by showing that constant-degree expanders (considered as metric spaces) cannot be embedded any better. Research supported by Czech Republic Grant GAČR 201/94/2167 and Charles University grants No. 351 and 361.     

Internal bremsstrahlung in the unique first-forbidden electron capture decay of 41Ca

The spectrum of internal bremsstrahlung photons has been measured for the unique first-forbidden decay of ⁴¹Ca. The experimental shape factor essentially deviates from the theoretical ones. Also, the overall photon intensity per K-capture is higher than predicted.     

A class of dimension-skipping graphs

Forn≧6 there exists a graphG with dimG=n, dimG*≧n+2, whereG* isG with a certain edge added.