Magnetic behavior of metastable fcc Fe-Cu after thermal treatments

A ferromagnetic and supersaturated fcc Fe_51Cu_49 solid solution has been obtained by mechanical alloying. After subsequent thermal treatments the fcc phase undergoes a spinodal decomposition which finally, at 780 K, yields a mixture of fcc and bcc phases. In this work, a systematic magnetic study is carried out on samples at diferent decomposition states in order to determine the process of transformation into the stable phases. We observe a 20% maximum diminution on the magnetic moment with increasing temperatures of the thermal treatment. The Mössbauer spectrum taken at 8 K shows that 20% of the Fe atoms are in a nonferromagnetic state. On the other hand, upon heating up to 723 K the roomtemperature coercive field increases dramatically to 640 Oe, and after cooling down to 10 K it decreases to 270 Oe. Deviations from the T law in the temperature dependence of the magnetization have been observed. This behavior is explained by fluctuations in composition due to the spinodal decomposition, which lead to fluctuations of the magnetic order parameters, i.e., magnetic moment and Curie temperature

Hair Trace Element and Electrolyte Content in Women with Natural and In Vitro Fertilization-Induced Pregnancy

The objective of the present study was to perform comparative analysis of hair trace element content in women with natural and in vitro fertilization (IVF)-induced pregnancy. Hair trace element content in 33 women with IVF-induced pregnancy and 99 age- and body mass index-matched control pregnant women (natural pregnancy) was assessed using inductively coupled plasma mass spectrometry. The results demonstrated that IVF-pregnant women are characterized by significantly lower hair levels of Cu, Fe, Si, Zn, Ca, Mg, and Ba at p < 0.05 or lower. Comparison of the individual levels with the national reference values demonstrated higher incidence of Fe and Cu deficiency in IVF-pregnant women in comparison to that of the controls. IVF pregnancy was also associated with higher hair As levels (p < 0.05). Multiple regression analysis revealed a significant interrelation between IVF pregnancy and hair Cu, Fe, Si, and As content. Hair Cu levels were also influenced by vitamin/mineral supplementation and the number of pregnancies, whereas hair Zn content was dependent on prepregnancy anthropometric parameters. In turn, planning of pregnancy had a significant impact on Mg levels in scalp hair. Generally, the obtained data demonstrate an elevated risk of copper, iron, zinc, calcium, and magnesium deficiency and arsenic overload in women with IVF-induced pregnancy. The obtained data indicate the necessity of regular monitoring of micronutrient status in IVF-pregnant women in order to prevent potential deleterious effects of altered mineral homeostasis

How do joint image statistics change with illumination?

The dependence of statistical properties of an image as a function of illumination direction is an exciting topic which was so far investigated experimentally, and also addressed theoretically for a special case of low-order moments of image features. In this paper we observe the principal relationship between the joint (co-occurrence) distribution of surface properties and the corresponding joint distribution of local image features. We focus on two kinds of statistics computed from local image neighbourhoods: (a) the joint distribution of pixel intensities, and (b) the joint distribution of binary patterns obtained by taking the signs of intensity differences between a selected reference pixel and all other pixels. We work with a non-parametric histogram representation of the probability distribution functions, and show how the frequencies in a histogram bin depend on illumination. Finally, we focus on approximating the illumination dependence of image statistics by a harmonic series. Experimental results obtained using a real surface are presented

Binary potassium-silicate glass irradiated with electrons

International audienc

Reconstruction of quadrics from two polarization views

Abstract. This paper addresses the problem of reconstructing textureless objects of quadric like shape. It is known that a quadric can be uniquely recovered from its apparent contours in three views. But, in the case of only two views the reconstruction is a one parameter family of quadrics. Polarization imaging provides additional geometric information compared to simple intensity based imaging. The polarization image encodes the projection of the surface normals onto the image and therefore provides constraints on the surface geometry. In this paper it is proven that two polarization views of a quadric contain sufficient information for a complete determination of its shape. The proof itself is constructive leading to a closed-form solution for the quadric. Additionally, an indirect algorithm is presented which uses both polarization and apparent contours. By experiments it is shown that the presented algorithm produces accurate reconstruction results.

Helmholtz stereopsis on rough and strongly textured surfaces

Helmholtz Stereopsis (HS) has recently been explored as a promising technique for capturing shape of objects with unknown reflectance. So far, it has been widely applied to objects of smooth geometry and piecewise uniform Bidirectional Reflectance Distribution Function (BRDF). Moreover, for nonconvex surfaces the inter-reflect ion effects have been completely neglected. We extend the method to surfaces which exhibit strong texture, nontrivial geometry and are possibly nonconvex. The problem associated with these surface features is that Helmholtz reciprocity is apparently violated when point-based measurements are used independently to establish the matching constraint as in the standard HS implementation. We argue that the problem is avoided by computing radiance measurements on image regions corresponding exactly to projections of the same surface point neighbourhood with appropriate scale. The experimental results demonstrate the success of the novel method proposed on real objects