The strange behavior of thermal energy loss in chaotic motion of a Bloch wall is studied by using entropy. The thermal energy loss due to domain-wall motion is calculated by integrating a damping term. The entropy of domain-wall motion is calculated by using the probability of the state-points distribution in the phase space. The results of computer simulation show that the thermal energy loss in the periodic window of the bifurcation diagram increases in spite of the decrease in randomness of domain-wall motion, which seems to conflict with the first and second laws of thermodynamics. The chaotic entropy Sc of domain-wall motion is introduced into the equation of energy balance to solve the above conflict. Sc is a kind of “mechanical entropy”, and differs from thermodynamic entropy. The entropy S of the system is expressed as the sum of the chaotic entropy Sc of the domain-wall motion in the phase space and the entropy Sm related to the thermal energy loss by using the property of additivity of entropy. The results of computer simulation are interpreted as indicating that the value of Temperature ×∫21dSm (the thermal energy loss) increases so that it compensates for the decrease of Temperature ×∫21dSc (the randomness of motion) in the periodic window. It is explained that the thermal energy loss increases in spite of the decrease in randomness of motion in the periodic window.
We have developed the micro-fabricated cantilever with an MR sensor (MR cantilever) for scanning magnetoresistance microscope (SMRM). In order to improve the stability of the MR signal acquisition and the reproducibility of the system, we have proposed a new fabrication procedure for the SMRM cantilever. The MR cantilever with a high field sensitivity is realized and allows us to measure magnetic field quantitatively only for the relatively large external field. However, for the small field detection, superposition of topographic signals on the magnetic signals is not negligible. To avoid this problem, four-terminal SMRM cantilevers were fabricated. In addition, we accomplish to make the cantilever with a high spatial resolution by miniaturizing the MR element.
In the case of conventional type tubular linear induction motor (LIM), due to the higher value of leakage reactance, the air gap flux is decreased. In the flux-concentration type linear induction motor (FCLIM), the leakage flux is reduced considerably and more flux is concentrated into the air gap, resulting in an increase of the developed thrust. The performance characteristics obtained using per phase equivalent circuit parameters are not accurate mainly due to the configuration of the primary core with ends and the unbalanced input voltages. In this paper the performance characteristics of FCLIM and normal tubular LIM are compared using threephase equivalent circuit parameters, which are determined considering the unbalanced input currents and mutual reactances.