57Fe Mössbauer investigation of the ternary hydride Pd3FeHx

Ordered alloys of Pd₃Fe are shown to readily absorbe hydrogen through electrolytic loading. The resultant ternary hydride phase is observed to retain the fcc structure of Pd₃Fe with approximately the same lattice constant. The ⁵⁷Fe hyperfine field determined by Mössbauer spectroscopy is found to be 30% smaller in the hydride compared to Pd₃Fe. The reduction appears to be associated with a perturbation of the Pd moment by hydrogen. The results suggest the occupation of one type of interstitial site in the structure. The absence of the site in disordered Pd₃Fe would explain the much smaller hydrogen capacity observed for this alloy.     

A complex impedance study of Pt∣NaCl and C∣NaCl interfaces

The a.c. impedance of Pt∣NaCl∣Pt and C∣NaCl∣C cells was measured in the frequency range from 10^?3 to 10³ Hz. Two contributions to the interface impedance could be distinguished, hindered charge transfer and an adsorption/desorption or slow reaction contribution, the latter being the rate determining step in the frequency range studied. An approximately symmetric nonlinear dependence of both the capacitance and the conductance on overvoltage was found at the lowest frequencies, indicating that the crystal/electrode interface is in a state which can be characterized as close to equilibrium. It should be ensured by two electrochemical reactions of approximately equal rates. The concept of a temporarily reversible electrode is introduced. It is a result of the ability of ions to discharge at the interface and to produce a finite reservoir of adsorbed or absorbed reaction products. An external voltage increases or reduces this reservoir, and therefore only a transient electric current may be carried by a backward reaction.     

Neutron diffraction study of RECo2Si2 intermetallics

A neutron diffraction study of polycrystalline RECo₂Si₂ intermetallics (RE = Pr, Nd, Tb, Ho, Er) carried out at liquid helium temperature shows the presence of a collinear antiferromagnetic ordering of +?+? type. Magnetic moment is localized on RE ions only and amounts to the RE³⁺ free ion value. In ErCo₂Si₂ the magnetic moment is normal to the tetragonal unique axis, whereas in the remaining compounds the magnetic moment is aligned along it. Néel points were determined from the temperature dependence of magnetic peak heights.     

111In(111Cd) quadrupole interaction in the chalcogenide spinel CdCr2Se4

The¹¹¹Cd quadrupole coupling in the spinel CdCr₂Se₄ is investigated by TDPAC after different sample treatments. The experiments are consistent with Se vacancies causing the non-cubic probe environments and with the assumption that the majority of the¹¹¹In atoms are positioned at A-sites.     

Measurement of the electron distribution function in flowing afterglow plasma by means of Langmuir probe

Conclusion In the present report an attempt has been made to use the second derivative method for measurements of the electron distribution function in flowing afterglow plasma. It has been shown that using the cross-correlation technique, this method seems to be a useful tool for flowing afterglow plasma investigation.     

Soliton experiments in stimulated Raman scattering

Experimental observations of solitons in stimulated Raman scattering are reported. Soliton formation resulted from the introduction of a phase shift in the incident Stokes beam as predicted by theory. Pulse sharpening and retardation on propagation in the Raman medium have been observed along with amplitude diminution. The first two features were predicted and the third was not. Spontaneous soliton formation has been observed in the absense of any amplitude modulation or apparent phase shift in the optical fields, indicating that additional sets of initial conditions may result in soliton formation.Work performed under the auspices of the U.S. Department of Energy.     

Thermal expansion of cadmium fluoride crystals at high temperatures

The thermal expansion coefficient of cadmium fluoride crystals has been measured over the temperature range of 300 to 1070 K. The data fit well to measurements done by other authors in the range 80–300 K. At temperatures above 1070 K the thermal expansion coefficient shows an anomalous behaviour which has been attributed to the formation of cadmium oxide on the surface of the sample.     

Über Anzahl und Verteilung der Scheitel ebener Bogen

Zusammenfassung Seit der Entdeckung des 4-Scheitel-Satzes durch S. Mukhopadhaya (1909) und A. Kneser (1912) hat sich eine umfangreiche Literatur über Scheitel- und verwandte Sätze entwickelt. Unter anderem wurden ebene Bogen auf Scheitel hin untersucht bzgl. Charakteristiken, welche von k 1 Parametern stetig abhängen. Wir legen für die wichtigsten Sätze aus diesem Teil der Theorie überarbeitete Definitionen und Beweise unter vereinfachten Voraussetzungen vor.

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