Electronic and magnetic properties of rare-earth-transition-metal glasses

We have studied the magnetic and electrical properties of several amorphous rare-earth—transition-metal alloys obtained by splat cooling. Low-field susceptibility, high-field magnetization and electrical resistivity measurements were made between 1.6 and 300 K. Mössbauer results are reported for (Gd₆₅Fe₃₅)₉₀B₁₀ at the temperatures of 80 and 300 K. Resistivity measurements show both positive and negative coefficients and in some cases maxima or minima that are associated with magnetic ordering or Kondo-type scattering, respectively.     

Centrifugal mechanism for molecular dissociation in high-energy collisions with solid surfaces

A simple model is proposed for molecular dissociation probabilities in impulsive collisions with surfaces. Dissociation is assumed to follow rotational excitation high enough to break the molecule. The model was tested against exact classical simulations for I₂, Li₂ colliding with smooth surfaces. Agreement is better than a factor of 2 over a wide range of energies.     

A remark on the structure of non-stoichiometric copper-manganese ferrite

Czechoslovak Journal of Physics -     

Equilibria in a proportional reinsurance market

The classical theory is adapted to the situation where the risk exchange of n insurance companies is an exchange of payments that belong to a certain linear class of random variables, for example the payments corresponding to certain layers of the aggregate claims. Similarly, a price equilibrium is considered, where the companies can purchase payments of a linear class. An example is the case where each company buys proportional coverage for its own claims and sells proportional coverage for the claims of the other companies.     

Optimization of the ion-pair high-performance liquid chromatographic separation of purine derivatives in erythrocytes, thymocytes and liver mitochondria

Various methods are described for the analysis of purine derivatives in biological samples by ion-pair high-performance liquid chromatography (HPLC) with both gradient and isocratic systems. A new approach is proposed that is suitable for the separation of nuclei acid constituents in different cells with a specific enzymatic activity pattern. The ion-pair HPLC methods were developed for the analysis of erythrocytes, lymphocytes and mitochondria acid-soluble fractions in clinical and experimental studies of normal and altered nucleotide metabolism. The results of studies of purine metabolite redistribution in mouse liver mitochondria during a 30-min incubation at 37 degrees C and data on purine metabolic alterations in mouse thymocytes during hepatoma growth are discussed.     

Hyperfine interaction and g-factor measurements in Er isotopes

Energy levels in ¹⁶⁰Er and ¹⁵⁹Er were excited in the reactions ²⁸Si(¹³⁶Xe, 4n)¹⁶⁰Er and ²⁸Si(¹³⁶Xe, 5n)¹⁵⁹Er, and the product nuclei, recoiling with a velocity v = 0.07c were stopped in a plunger instrument after traversing a volume of hydrogen gas. The angular distribution of de-excitation γ-rays was studied as a function of flight time and gas pressure. Appreciable perturbations were detected in ¹⁶⁰Er at times as short as 2 ps and in an angular momentum region as high as 12?. No perturbation could be detected in the $\text{21}\text{2}{}^{\mathrm{+}}$ level of ¹⁵⁹Er even after 12 ps, signifying a low value for the g-factor of this level.     

X-Ray Bremsstrahlung Measurements of an Intense Relativistic Electron Beam Propagating in a Plasma

Information on the peak electron energy, angular spread, and current density of a relativistic electron beam propagating in a plasma column is obtained from measurements of two-absorber transmission ratios, anistropy, and intensity, respectively, of x-ray bremsstrahlung from thin target foils in the plasma. Measurements indicate a 10% loss in peak electron energy and a factor of two loss in peak beam intensity over the distance of the plasma column, and show a large angular spread in the beam.