Iron Core Structure Research Articles

Supernova neutrinos, neutrino oscillations, and the mass of the progenitor star

We investigate the initial progenitor mass dependence of the early-phase neutrino signal from supernovae taking neutrino oscillations into account. The early-phase analysis has advantages in that it is not affected by the time evolution of the density structure of the star due to shock propagation or whether the remnant is a neutron star or a black hole. The initial mass affects the evolution of the massive star and its presupernova structure, which is important for two reasons when considering the neutrino signal. First, the density profile of the mantle affects the dynamics of neutrino oscillation in supernova. Second, the final iron core structure determines the features of the neutrino burst, i.e., the luminosity and the average energy. We find that both effects are rather small. This is desirable when we try to extract information on neutrino parameters from future supernova-neutrino observations. Although the uncertainty due to the progenitor mass is not small for intermediate $\theta_{13}$ ($10^{-5} \lesssim \sin^{2}{2 \theta_{13}} \lesssim 10^{-3}$), we can, nevertheless, determine the character of the mass hierarchy and whether $\theta_{13}$ is very large or very small.

Hyperfine interactions in the iron cores from various pharmaceutically important iron–dextran complexes and human ferritin: a comparative study by Mössbauer spectroscopy

Mössbauer spectroscopy has been used to study the hyperfine interactions in the iron cores of pharmaceutically important industrial and elaborated iron–dextran complexes (ferritin models) and human ferritin. Mössbauer spectra of frozen solutions and lyophilized samples of iron–dextran complexes at 87 K demonstrated magnetic, superparamagnetic and paramagnetic states of iron in various complexes. Mössbauer spectra of human ferritin in frozen solution and lyophilized form showed paramagnetic state of iron at 87 K. Small variations of Mössbauer hyperfine parameters were observed for different samples at 87 and 295 K, respectively, supposing the homogenous iron cores. The values of quadrupole splitting for iron–dextran complexes and ferritin in frozen solutions at 87 K varied from 0.639 to 0.744 mm/s while those of lyophilized samples at 87 K varied from 0.714 to 0.788 mm/s. The values of quadrupole splitting for iron–dextran complexes and ferritin in lyophilized form at 295 K varied from 0.687 to 0.741 mm/s. The values of hyperfine magnetic fields on the 57Fe nuclei in several iron–dextran complexes at 87 K varied from ∼231 to ∼485 kOe. These small variations of the hyperfine parameters were related to several types of the hydrous iron oxide microstructural modifications in the core and variations of the iron core size. The influence of lyophilization on the iron core structure was also assumed. In addition, Mössbauer spectra were evaluated in supposition of heterogeneous iron core in all samples.

両面駆動形リニアパラメトリックモータの磁心構造と特性値の関係

This paper describes the relations between the iron-core structure and the characteristics of a linear parametric motor with double driving surfaces. This linear motor has a number of advantages; it can be used by a single-phase (1 φ) power source, it is very easy to maintain, and it has a very simple shape, because it can be assembled by using an I-shaped core. This linear motor has two common magnetic circuits and two driving surfaces. The thrust of a double-surface driving-type linear motor was higher than that of a 4-legged linear motor.

An analysis of iron-dextran complexes by Mössbauer spectroscopy and positron annihilation technique

Abstract The combination of two modern spectroscopic techniques was used for comparative microstructural analysis of several iron-dextran complexes which were used or elaborated as drugs for treatment of iron-deficiency anemias. Slight variations of the iron electronic and magnetic structure in different iron-dextran complexes were detected by Mossbauer spectroscopy. The differences of iron core structure and size were shown in studied complexes also. Variations of dextran structure were detected by the positron annihilation technique for investigated irondextran complexes. These results were considered with histological and histochemical data for iron-dextran complexes to compare the differences of their microstructural variations and biochemical pathways.

An experimental analysis of DC excitation of transformers by geomagnetically induced currents

DC excitation of transformers due to geomagnetically induced currents was studied by model experiments. First, differences in the DC excitation phenomenon due to the iron core structure were studied using three typical small-scale models. The results verified that single-phase three-legged cores were most susceptible and three-phase three-legged cores least susceptible to such excitation effects. Secondly, the local heating due to DC excitation was quantitatively assessed using large-scale core form and shell form models with the most susceptible single-phase three-legged cores. The results demonstrated that the maximum temperature rise was approximately 110/spl deg/C due to the GIC (200 A/3 phases).< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The effect of iron core structure on supernovae

Un modele de supernova, considerant le transport hors equilibre de toutes les saveurs des neutrinos et anti-neutrinos et les effets de diffusion des neutrions electroniques est developpe. Les profils S et Y e du noyau de fer sont analyses pour la phase de destabilisation et d'effondrement.