In this study, we have considered the physical adsorption of Fe₃O₄ magnetic nanoparticles - having a size of a few tens of nanometers - onto the surface of a microcantilever, and observed the following resonance frequency shift of the microcantilever. The change in the effective mass of the microcantilever depending on the level of the surface adsorption of nanoparticles on the microcantilever has been determined from the observed resonance frequency shift based on a simple mechanical model, leading to the estimation of the number of nanoparticles adsorbed on the microcantilever surface.

This paper presents characteristics of design and analysis on the surface mounted permanent magnet type BLDC Motor, which is employed for a Ventilation Jet-Fan. To satisfy required specifications of the BLDC motor. Not only the ratio of the magnetic loading is used at the step of the initial design, but also an element finite method is taken at the step of the detail design. Finally both the design and analysis results are verified with experimental results.

This paper investigates the design of a single-phase brushless DC (BLDC) motor by employing asymmetric air gap to meet the characteristics of vacuum cleaner applications such as low torque and high speed. Also, one of the key objectives has to be reasonable efficiency since it is a disadvantage in a single-phase BLDC motor. Asymmetric stator pole surface needs to be effectively customized to satisfy several important performances such as starting torque and continuous torque at high speeds. Starting torque is modified by using a mechanism of phase difference between cogging torque and back electromotive force. In this paper, two types of asymmetric air gap are designed by changing the ratio of maximum air gap to minimum air gap, and switching on and off angles are determined at the same time after comparing key performances in case of no load and rated operation conditions.

In this paper, characteristics of propagated pulse signals are analyzed for detection of water trees in power cables using simulation-based TDR (Time Domain Reflectometry). COMSOL Multiphysics software is used for time-domain simulations of propagated pulse signals with high frequency components. The water trees with various penetration depths and lengths are modeled by axis-symmetry or 3D geometry, depending on the shapes of the water trees considered. The reflected waveforms and RMS values of the applied diagnostic pulse signals are analyzed according to the shapes and lengths of the water tree models and outer conductor conditions. Also, the propagation velocity of the pulse signal is calculated considering the material property of XLPE insulator in the cable, and the location of the water tree is obtained by checking the starting point of the reflected pulse. Furthermore, positional errors with respect to the actual positions of the water trees are calculated.

We review here the recent progress on the study of the magnetization dynamics as well as the basic principle of the related phenomena. The static properties of the magnetic domain walls and skyrmions as well as their dynamic properties under application of magnetic field and/or spin current are discussed together with the Dzyaloshinskii-Moriya interaction. Finally, the basic principle and recent progress in the antiferromagnetic spintronics are introduced.