Search for delayed fission products from superheavy nuclei in the reaction136Xe+208Pb

The production of superheavy elements in binary reactions of the type²⁰⁸Pb (¹³⁶Xe, X) Y was investigated atE _c.m.=470 MeV. The experiment was designed to search for delayed fission products from elements withZ between 108 and 116 and fission lifetimes ofΤ?10^?12 s. No fission events were observed the upper limit for the formation cross section being 1.2 Μbarn.     

Variation of material parameters along the growth direction of liquid encapsulated Czochralski grown GaAs ingots

The variation of material properties along the growth axis of single crystal LEC GaAs ingots is studied. Parameters investigated include concentration and lateral variation of EL2, photoluminescence intensity, resistivity, the concentration of extrinsic shallow acceptors and, after test implantation, the sheet resistivity. Correlations between the observed trends are identified and discussed in terms of compensation and segregation. In general, a very satisfactory homogeneity is found. Remaining variations are identified and evaluated with respect to their device-relevant consequences.     

On the fundamental solutions of the operators of S. Timoshenko and R. D. Mindlin

Our recent paper about some new fundamental solutions is complemented by a representation of the fundamental solution of certain evolution operators of fourth order in terms of a family of fundamental solutions of operators of second order. By applying this to the operators of vibrating beams and plates we deduce representations of their fundamental solutions as simple definite integrals over tabulated functions.     

119Sn Mössbauer study of the CePtSn Kondo compound

We have measured¹¹⁹Sn Mössbauer spectra of the CePtSn and (Ce_0.9La_0.1)NiSn compounds in the range from 1.5 to 293 K. In CePtSn, the spectra observed above 8 K are well explained by an electric quadrupole interaction. The spectral shape changes below 8 K due to the presence of a magnetic hyperfine field produced by the ordering of the Ce magnetic moments. We have analyzed these spectra assuming an incommensurate magnetic structure. The temperature dependence of the magnetic hyperfine field matches with anS=1/2 mean field curve with a step at 5 K. In (Ce_0.9La_0.1)NiSn, no magnetic order exists down to 1.5 K.     

Soft modes in semiconducting SrTiO3: II. The ferroelectric mode

The frequency, temperature and wavevector dependence of the ferroelectric soft mode in semiconducting SrTiO₃ was investigated by temperature derivative Raman spectroscopy and by inelastic neutron scattering. A tremendous shift in mode frequency with free electron and oxygen vacancy concentration, respectively, was observed.     

Energy of the 5− isomer and (πg 9/2⊗vg 9/2) states in82Rb

Excited states in the doubly-odd nucleus⁸²Rb have been investigated via the reactions⁷⁹Br(,n) and⁷⁸Se(⁷Li,3n) using in-beam-ray spectroscopy. The level energy of the longlived 5^– isomer has been determined to 68.3 keV which is below the energy of the 2^– state found at 88.9 keV with a lifetime of=2.4(2) ns. A sequence of positive-parity states beginning with a 6⁺ level at 191.3 keV (=20(3) ns) and extending to a (10⁺) level has been interpreted to contain the two-particle configuration (g ₉/2 _9/2) and collective excitations.     

Light charged particles and clusters in coincidence with heavy fragments in the40Ar(1100 MeV)+13C incomplete fusion reaction. Simulated statistical decay analysis

Protons, deuterons, tritons,α-particles and Li have been studied in coincidence with evaporation residues produced at low impact parameter for the⁴⁰Ar(1100 MeV)+¹³C reaction. Experimental characteristics of the light particle — heavy residue correlations, and among them an effect of left-right asymmetry, are analyzed and discussed in some detail on the basis of Monte Carlo simulations. This reaction appears to be governed by an incomplete fusion process. Due to transverse emission of preequilibrium particles, the compound nuclei associated with light-particle-evaporation-residue coincidence events recoil at a non-zero degree lab. angle with some dispersion around this direction. When these effects are introduced into statistical decay calculations, it is then possible to reproduce various experimental results and to understand features like the asymmetry effect. Discrimination of light particles of preequilibrium and of evaporative origin appears possible.     

Sur le comportement asymptotique des potentiels d'une chaîne de Markov sur ℝ d

Résumé Dans cet article j'étudie le comportement à l'infini des potentiels des chaînes de Markov sur ^d (d3) proches du mouvement brownien, tout spécialement le cas des marches aléatoires, ainsi que des critères de transience et de récurrence inspirés de la méthode utilisée.

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We study the asymptotic behaviour of potentials of Markov chains on ^d (d3), closed to Brownian motion, and particularly the case of random walks. Following a similar approach, we give transience and recurrence criteria.

     

Ergodicity of a Class of Cocycles Over Irrational Rotations

It is proved that if is irrational and L²(S¹) with o(l/n)then for each mZ\{0} the corresponding skew product is ergodic. The rigidity of specialflows over irrational rotations with roof functions whose Fouriercoefficients are in o(l/n) is also shown.     

Microdefects in lec gallium phosphide and generation of dislocations in homoepitaxial layers

Acta physica Academiae Scientiarum Hungaricae - GaP LEC substrates doped with sulphur (N D−N A≈(3−7)×1017 cm−3) were characterized by transmission electron microscopy...