No abstract available

[en] The local mean spin density on B sites in ferrites containing Fe²⁺ and Fe³⁺ was determined with the aid of the Moessbauer effect. Locally adapted charge densities of 3d electrons are derived from a statistical distribution of impurities. The hyperfine field distributions measured were qualitatively and quantitatively adapted with the aid of a model of this type. (orig./WBU)

[en] The fabrication and testing of a niobium--tin strip, copper stabilized superconducting cable are described. The tests included both electric and mechanical properties. The manufacturing process is illustrated by 9 photographs

[en] The use of manipulators in nuclear power plants has become indispensable. They contribute greatly to more safety of nuclear power plants and to reduced radiation exposures of the service personnel. Their importance is going to increase even further in the future. Manipulators have been used for a number of years and have proved their merits in insepections and repair work in nuclear power plants in Europe, USA, and Asia. They have been employed, e.g., in inspecting some 175,000 steam generator tubes and repairing a total of approx. 10,000 tubes. Experience with a specialized manipulator has been accumulated in inspecting some 2800, and exchanging 1300, fuel assembly centering pins. (orig./GL)

[en] Ferromagnetic metallic glasses have been studied at 300 and 75 K by ⁵⁷Fe Moessbauer spectroscopy. The line broadening results from a distribution of hyperfine fields with a relative width of 10-15%. Heat treatment near the crystallization temperature give rise to several phases: α-Fe, Fe₂B and presumably a phase with a ratio Fe/B>=3. (Auth.)

[en] The investigation of Fesub(3-x)Msub(x)O₄ (M=Co or Ni) with Moessbauer spectroscopy gives evidence for substitutional disorder in these compounds and for Fe²⁺-Fe³⁺ electronic relaxation with frequencies higher as 10 MHz at room temperature. (Auth.)

No abstract available

[en] The Li⁺ ionic conductivity of LiNbO₃ has been measured in the temperature range 50 to 300 ⁰C usig two electrode arrangements (Ag⁺|Li|LiNbO₃|Ag^- and Ag⁺|Pt|LiNbO₃|Ag^-). Below 300 ⁰C the dc conductivity of LiNbO₃ was found to be more than two orders of magnitude higher using metallic Li as the anode than the conductivity in the case of an Ag anode. Activation energies of 0.5 eV perpendicular and 0.7 eV parallel to the c-axis were determined. IR spectra of OH centers gave hints upon Li in-diffusion

[en] The Moessbauer spectra of iron-cobalt ferrites in the series Fesub(3-x)Cosub(x)O₄ were investigated to obtain more information concerning the influence of the variable amount of Fe²⁺ ions on the hyperfine field and isomer shift of the tetrahedral (A) and octahedral (B) Moessbauer Fe-sextets. While for the A-site Fe³⁺ ions, the Moessbauer spectrum consists of only one sextet which is almost independent of x, it was possible to split the B lines starting with x=0.1, thus allowing one to ascribe up to five different hyperfine fields at the Fe-nuclei in the composition range 0.1<=x<=0.7. The occurence of such a wide spectrum of hyperfine fields is probably due to a statistic distribution of the Co²⁺ ions over the B-sites. Then, under fulfilment of the local electrical neutrality condition, a statistic distribution of Fe²⁺ ions will also be reached giving rise (under the assumption of a strong electronic Fe²⁺-Fe³⁺ relaxation) to the observed values of B-sites hyperfine fields. (Auth.)

[en] In this paper we analyze the behavior of a gang-scheduling strategy that we are developing for the ASCI Blue-Pacific machines. Using actual job logs for one of the ASCI machines we generate a statistical model of the current workload with hyper Erlang distributions. We then vary the parameters of those distributions to generate various workloads, representative of different operating points of the machine. Through simulation we obtain performance parameters for three different scheduling strategies: (i) first-come first-serve, (ii) gang-scheduling, and (iii) backfilling. Our results show that backfilling, can be very effective for the common operating points in the 60-70% utilization range. However, for higher utilization rates, time-sharing techniques such as gang-scheduling offer much better performance