Isolation of short-lived isotopes of lanthanum and indium by β-diketonates sublimation

Trace amounts of lanthanum hexafluoroacetylacetonate and indium acetylacetonate were isolated by combination of methods, which includes synthesis of volatile elements -diketonates by nucleophilic ligands exchange and fractional sublimation. This method is useful for produce isotope generators.     

Anomalous behavior in the low temperature properties of UPd3

The low temperature specific heat of the hexagonal intermetallic compound UPd₃ reveals a contribution from low lying crystal field levels. In annealed or single crystal samples, sharp phase transitions are observed at temperatures of 6 and 7 K respectively. Correlation with resistivity, susceptibility and X-ray measurements in this temperature range indicate that the collective phenomenon is probably due to the electric quadrupole interaction between the U⁴⁺ ions.     

Low-cycle fatigue loading of BDS 25G pipeline steel

The behavior of BDS 25G pipeline steel, is studied for constant amplitude low-cycle fatigue. The same is done for the weld metal. Results are compared for temperatures of 20°C and 300°C, and tabulated for the estimate of different fatigue parameters.     

Laser induced breakdown spectroscopy for multielement analysis of powdered materials used in additive technologies

Additive manufacturing technologies utilizing metal parts production with layer by layer printing are of high demand for different fields of science and technology. Analytical chemistry is challenged to provide multielemental quantitative analysis of any metal powders within a few minutes and onsite to fulfil the requirements for high quality metal parts production. Powder materials utilized in additive technologies were quantitatively analyzed by laser induced breakdown spectroscopy for the first time. Laser induced breakdown spectroscopy mapping of loose metal powder attached to the double-sided adhesive tape provided high reproducibility of measurements even for powder mixtures with large difference of particles densities (tungsten carbide particles in nickel alloy powder). Laser induced breakdown spectroscopy analytical capabilities were estimated for tungsten and carbon analysis by calibration curve construction and accuracy estimation by leave-one-out cross-validation procedure. Laser induced breakdown spectroscopy and X-ray fluorescence spectroscopy techniques comparison revealed better results for laser induced breakdown spectroscopy analysis. Improved accuracy of analysis and capability to quantify light elements (carbon, etc.) demonstrated the potential of laser induced breakdown spectroscopy as a promising technique for express onsite multielement analysis of powder materials utilized in additive technologies.     

Compact self-dual Hermitian surfaces

In this paper, we obtain a classification (up to conformal equivalence) of the compact self-dual Hermitian surfaces. As an application, we prove that every compact Hermitian surface of pointwise constant holomorphic sectional curvature with respect to either the Riemannian or the Hermitian connection is Kähler.

     

ESR study of exchange parameters in praseodymium monochalcogenides and monopnictides: Correlation with a pressure experiment

The exchange interaction between gadolinium ions and the host praseodymium ions in praseodymium monochalcogenides does not vary considerably across the chalcogenide series as it does in the case of the Van Vleck pnictides. The existence of a correlation between these results and a previous pressure study by Guertin et al. is pointed out.     

The steady‐state probabilities for regenerative semi‐Markov processes with application to prevention and screening

There is a growing interest in planning and implementing broad‐scale clinical trials with a focus on prevention and screening. Often, the data‐generating mechanism for such experiments can be viewed as a semi‐Markov process. In this communication, we develop general expressions for the steady‐state probabilities for regenerative semi‐Markov processes. Hence, the probability of being in a certain state at the time of recruitment to a clinical trial can be calculated. An application to breast cancer prevention is demonstrated. Copyright © 1999 John Wiley & Sons, Ltd.