Free energy and thermodynamical critical fieldH c (T) of a superconductor with crystalline-field-split magnetic impurities: (La/itPr)Sn3

An expression for the free energy of a superconductor containing magnetic impurities with crystalline-field-split energy levels is derived. It is used to calculate the thermodynamic critical fieldH _c (T) of(La Pr)Sn ₃ . ExperimentallyH _c (T) is determined from measurements of the heat capacity of(LaPr)Sn ₃ in the normal and superconducting states. The two results are in general agreement and demonstrate the role of the inelastic pair-breaking mechanism in this nonmagnetic ground-state system.Supported by the U.S. Energy Research and Development Administration under Contract No. ERDA E(04-3)-34 PA 227.     

Analysis of perchlorate in human urine using ion chromatography and electrospray tandem mass spectrometry

Because of health concerns surrounding widespread exposure to perchlorate, we developed a sensitive and selective method for quantifying perchlorate in human urine using ion chromatography coupled with electrospray ionization tandem mass spectrometry. Perchlorate was quantified using a stable isotope-labeled internal standard ((18)O(4)-perchlorate) with excellent assay precision (coefficient of variation <5% for repetitively analyzed quality control material). Analytical accuracy was established by blind analysis of certified proficiency testing materials prepared in synthetic urine matrix; calculated amounts deviated minimally from true amounts, with percent differences ranging from 2% to 5%. Selective chromatography and tandem mass spectrometry reduced the need for sample cleanup, resulting in a rugged and rapid method capable of routinely analyzing 75 samples/day. The lowest reportable level (0.025 ng/mL) was sufficiently sensitive to detect perchlorate in all human urine samples evaluated to date, with a linear response range from 0.025 to 100 ng/mL. This selective, sensitive, and rapid method will help elucidate any potential associations between human exposure to low levels of perchlorate and adverse health effects.     

Solution-Condensed YBa2Cu3O7 −x Superconductor Thin Films from Thermosetting Metal-Organic Precursors

Two different multimetal organic compounds were synthesized and used to deposit thin Y:Ba:Cu oxide films on selected metal and ceramic substrates by the dip-coating method. The rheology of the precursors is strongly influenced by the organic ligand, types of solvent, solvent–water molar ratio, and processing method. The precursor compounds were converted to suitable viscosity to achieve uniform film thickness processing on complex geometry. Superconducting transition temperatures T _c in the range of 89 to 93 K have been measured, depending on processing parameters used. The critical current density, J _c of the solution-coated films had values comparable to those for poly-crystalline samples. Y123 films exhibit c -axis alignment on Ag substrates. A prototype high- Q cavity was coated with Y123 and its performance was evaluated.     

Follow-up study of isolation-reared and mother-reared rhesus monkeys paired with preadolescent conspecifics in late infancy: Cross-sex pairings.

8 rhesus monkeys, 4 of each sex, which had been reared either with their mothers or in social isolation during early infancy, were paired with preadolescent conspecifics during late infancy. Some isolate-reared Ss appeared to have gained from this social experience. At nearly 3 yrs of age, each S was paired (sequentially) with 2 other-sex animals (1 isolate- and 1 mother-reared) after having been housed alone for the entire 2nd (and most of the 3rd) yr of life. Little social interaction occurred between the members of any pair. Several significant effects of rearing experience indicated that social experience with preadolescents in late infancy did not permanently reverse the deleterious effects of early isolation. However, the mother-reared Ss also failed to establish social rapport with one another. Comparison of these results with those of similar research employing mother-reared animals which had received supplemental social experience during the 2nd yr of life suggests that such social experience is of some importance for optimal development of later sociosexual behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of neutron irradiation on the upper critical magnetic field of superconducting Mo3Os

The effect of irradiation with high-energy (E>1 MeV) reactor neutrons on the upper critical magnetic fieldH _c2 (T) and the superconducting transition temperatureT _c has been determined for the A15 compound Mo₃Os. An increase ofH _c2(0) by 37% relative to its unirradiated value was observed for a neutron fluence of1.7×10¹⁹ n/cm². For the same fluence,T _c was found to decrease by 12%. The results are discussed in terms of defects in the A15 structure and their influence onH _c2(0).