Magnetization and Specific Heat of UCo0.95T0.05Al (T = Fe, Ni) Single Crystals

We present the first single-crystal study of Fe and Ni doped U(Co_1-x T _x )Al compounds in comparison to the parent compound, the itinerant 5f-electron metamagnet UCoAl. Magnetization and specific-heat data measured in the temperature range of (1.8-300) K and in fields up to 10 T are analyzed and discussed. Both compounds exhibit a strong uniaxial anisotropy with the dominating magnetic response along the c-axis of the hexagonal ZrNiAl-type structure. Ni substitution yields an increase of the critical field for metamagnetism; UCo_0.95Fe_0.05Al is ferromagnetic below 30 K. Temperature evolution of the entropy change between 0 and 10 T points to involvement of magnetic correlations or spin fluctuations in the paramagnetic compounds UCoAl and UCo_0.95Ni_0.05Al.     

Spectroscopic investigation of 4f correlations in CeAg; comparison between LDA and many-body descriptions

High resolution photoemission and bremsstrahlung isochromat spectroscopy experiments have been carried out on CeAg and LaAg. From a comparison between these two compounds, we extract the cerium 4f spectral function, we compare it with band structure calculations and with many-body model simulations based on the single-impurity Anderson Hamiltonian. We show that the localized 4f charge estimated from previous band structure calculations cannot be identified with the 4f occupation number deduced from the Anderson model.     

Staffing Rosters with Breaks — A Case Study

A complex manual rostering system for directory assistance, telephone operators has been rationalized and the technique of integer programming used to automatically generate staff rosters. These rosters can be generated by relatively unskilled clerical staff. They result in operator costs comparable to manually generated rosters and can be produced in a fraction of the time taken to produce their manual counterparts. Implementation is reported.     

Bromination of 4-substituted thiazolylhydrazones

4-Phenyl- and 4-methylthiazolylhydrazones were brominated in chloroform and acetic acid. The use of 1.5 equivalents of bromine led to the exclusive formation of the 5-halo derivatives. Effects of substituents on the thiazole ring and of the hydrazone fragment aromatic ring on the course of the reaction were discovered.Urals State Technical University-UPI, 620002 Yekaterinburg. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 991–995, July, 1995. Original article submitted March 1, 1995.     

Spectral shift function and trace formula

The complete proofs of Krein’s theorem on the spectral shift function and the trace formula are given for a pair of self-adjoint operators such that either (i) their difference is trace-class or (ii) the difference of their resolvents is trace-class. The proofs, essentially due to Krein, is based on Herglotz’s theorem on the boundary value of the analytic functions whose imaginary part is non-negative on the upper half plane, and an almost optimal class of functions are obtained for which the trace formula is valid. Also an alternative method based on Weyl-von Neumann’s theorem for self-adjoint operators, avoiding the complex function theory and inspired by Voiculescu’s work, is given for the first case. Furthermore, some applications of the spectral shift function have been discussed.     

Confinement of electrons and ions in a combined trap with the potential for antihydrogen production

Experiments with electrons and ions in a combined trap are reported. The unique capability to confine particles with opposite charge and very different mass simultaneously in the same spatial region makes the combined trap a promising device for future synthesis of antihydrogen.