Complex magnetic phases in LuFe2O4

DC magnetization and AC susceptibility measurements on LuFe₂O₄ single crystals reveal a ferrimagnetic transition at 240 K followed by additional magnetic transitions at 225 K and 170 K, separating cluster glass phases, and a kinetically arrested state below 55 K. The origin of giant magnetic coercivity is attributed to the collective freezing of ferrimagnetic clusters and enhanced domain wall pinning associated with a structural transition at 170 K. Magnetocaloric effect measurements provide additional vital information about the multiple magnetic transitions and the glassy states. Our results lead to the emergence of a complex magnetic phase diagram in LuFe₂O₄.     

Linear convergence of the generalized Douglas–Rachford algorithm for feasibility problems

In this paper, we study the generalized Douglas–Rachford algorithm and its cyclic variants which include many projection-type methods such as the classical Douglas–Rachford algorithm and the alternating projection algorithm. Specifically, we establish several local linear convergence results for the algorithm in solving feasibility problems with finitely many closed possibly nonconvex sets under different assumptions. Our findings not only relax some regularity conditions but also improve linear convergence rates in the literature. In the presence of convexity, the linear convergence is global.     

An efficient improvement of gift wrapping algorithm for computing the convex hull of a finite set of points in ℝ n $\mathbb {R}^{n}$

Numerical Algorithms - In this paper, we present an efficient improvement of gift wrapping algorithm for determining the convex hull of a finite set of points in $\mathbb {R}^{n}$ space, applying...     

Improvement on delay dependent absolute stability of Lurie control systems with multiple time delays

Absolute stability of Lurie control systems with multiple time-delays is studied in this paper. By using extended Lyapunov functionals, we avoid the use of the stability assumption on the main operator and derive improved stability criteria, which are strictly less conservative than the criteria in [2] and [3].     

Continuity of solution maps of parametric quasiequilibrium problems

In this article, we consider a parametric vector quasiequilibrium problem in topological vector spaces. Sufficient conditions for solution maps to be lower and Hausdorff lower semicontinuous, upper semicontinuous and continuous are established. Our results improve recent existing ones in the literature.     

Mathematical Evaluation of EBSD Data

In this work, a short overview is given, how data resulting from Electron Backscatter Diffraction (EBSD) measurements can be used to obtain a discrete version of the Orientation Distribution Function (ODF). Discrete ODFs are necessary, e.g. for micromechanically based simulations of metal forming operations based on the finite element method. To use EBSD data for simulations several processing steps are necessary as conversion and segmentation of the EBSD measurement data [1], definition of a fundamental zone in Euler space and a procedure for the tesselation of this zone [2]. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)