The impact of magnetoelasticity on structural phase transitions in cubic ferromagnets
Influence of the magnetoelastic interaction on the structural phase transitions in cubic ferromagnets is investigated on the basis of a Ginzburg-Landau theory. It is shown that for the case of a positive magnetic anisotropy constant the structural phase transitions are not accompanied by a spin-reorientation. In the magnetic state the high-temperature phase has small deformations caused by the magnetostriction. For the case of a strong magnetoelastic coupling these deformations lead to vanishing of the first order structural transitions. Corresponding critical points are determined. Due to the magnetoelastic interaction a first order magnetic phase transition can occur simultaneously with a structural first order transformation. The constrained theory allows to calculate a realistic (T,x)-phase diagram for Ni2+xMn1−xGa alloys. 64.10.+h, 64.70.Kb, 75.30.Gw, 75.80.+q Typeset using REVTEX 1
The Landau theory of phase transitions: A mechanical analog
The Landau theory of phase transitions occupies a centerpiece position in physics. We illustrate the theory by a pedagogical example at the pre-university level. In the example a bead of mass is threaded on a ring which is set rotating about a vertical diameter. The dynamics of the bead mimics key features of the Landau theory.
Study on workspace analysis and simulation of 6-DOF painting robot based on monte-carlo method
Comparing recent kinds of methods working on robot workspace when we design to calculate the workspace of 6R painting robot,we bring Monte-Carlo method to analysis the workspace according to the actual working condition. With robot Tool Center Point(TCP) position aggregate via the solution of forward kinetic equation,Monte-Carlo method analysis and simulate painting robot workspace efficiently.