Synthesis and magnetic properties of haematite with different particle morphologies

Abstract Haematite particles of four different morphologies (polyhedral, platelike, needlelike and diskshape) were synthesized by the hydrothermal method. The morphology and average particle diameter (1.4; 7.4; 0.2 and 0.12 mm, respectively) were determined by transmission electron microscopy (TEM) combined with electron diffraction. The haematite samples were studied by transmission Mossbauer spectroscopy in the temperature range 4.2-300 K. In all cases, a weak ferromagnetic phase (WF) was present above the Morin temperature of 230 K and found to coexist with an antiferromagnetic phase (AF) below this temperature. However, the populations of the two phases at 230 K were demonstrated to depend on the morphology of the particles. Moreover, the WF and AF phases exhibit a different dependence of the magnetic texture on temperature and particle morphology

MÖSSBAUER STUDY OF THE TIME DEPENDENCE OF THE FORMATION OF Eu2+ AFTER THE ELECTRON CAPTURE DECAY OF 153Gd In SmCl3

Les conséquences chimiques de la désintégration par capture d'électrons de 153Gd en SmCl3 ont été étudiées par des expériences de rétrodiffusion Mössbauer avec les rayons gamma de 97 keV et 103 keV de 153Eu. Pour les deux résonances on observe un pic de 1'Eu2+ à côté du pic dominant de l'Eu3+, mais l'intensité de la contribution de 1'Eu2+ dans le spectre de 97 keV est plus faible que l'on espère à partir du spectre de 103 keV. Cela indique que l'Eu2+ est formé dans un temps typique de l'ordre du temps de vie moyen du niveau de 97 keV (τ97 = 0,3 ns). En appliquant la méthode des moindres carrés à une fonction appropriée aux données on trouve que le temps de formation de l'Eu2+ doit être entre les limites 0,2 ns ≤ τ e 1 ns.The chemical consequences of the electron capture decay of 153Gd in anhydrous SmC13 have been studied by Mössbauer backscattering experiments with the 97 keV and 103 keV gamma rays in 153Eu. With both resonances the formation of Eu2+ is observed in addition to the dominant Eu3+ peak, but the intensity of the Eu2+ contribution in the 97 keV Mössbauer pattern is less than expected by comparison with the 103 keV spectrum. This indicates that the Eu2+ is formed within a typical time of the order of magnitude of the lifetime of the 97 keV level (τ 97 = 0.3 ns). From least squares fits of appropriate lineshapes to the data one finds that the time for the formation of Eu2+ must be within the limits 0.2 ns ≤ τ e ≤ 1 ns

Fe- and Eu-Doped TiO2TiO_2 Photocatalytical Materials Prepared by High Energy Ball Milling

To determine resource utilization in controller naïve children diagnosed with asthma receiving initial therapy with fluticasone propionate (FP) and salmeterol (SAL) in a single inhaler (FSC), FP alone, montelukast (MON), inhaled corticosteroid (ICS) + SAL from separate inhalers, or ICS + MON.A retrospective, observational, 18-month (6-month pre-index and 12-month follow-up) database study using medical and pharmacy claims from a 5 million member managed care organization. Multivariate modeling was used to evaluate post-index resource utilization and asthma-related costs. Refill rates during the 12-month follow-up period were compared across cohorts.The study included controller-naïve children (n = 9192) aged 4-17 years with an asthma diagnosis. Children treated with FSC were significantly less likely to receive additional prescriptions for short-acting beta-agonists compared with all other cohorts (p <or= 0.007) and oral corticosteroids compared with the MON, ICS + SAL, and ICS + MON cohorts (p <or= 0.009). Children receiving FSC were also significantly less likely to add another controller therapy compared with children started on FP alone, MON, or ICS + SAL (p <or= 0.001) and to receive care in an emergency department or hospital compared with children receiving ICS + MON (p < 0.001). The number of prescriptions for FSC in the 12-month post-index period was greater (p < 0.05) than the number of ICS claims in the FP, ICS + SAL, and ICS + MON cohorts. Compared with FSC, the adjusted total asthma-related post-index costs were greater (p <or= 0.008) in the MON and ICS + MON cohorts. Although adherence was greater with MON compared with FSC, MON was associated with less favorable clinical outcomes and greater resource utilization and costs.FSC in children is associated with improved clinical outcomes and decreased resource utilization compared with other controller regimens