• Journal of Magnetics
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• v.17 no.2
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• pp.100-108
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• 2012

Flux concentrated permanent magnet transverse flux machines, FCPM-TFMs, with segmented stators require multi-turn concentric saddle coils to replace the ring coils, which are normally utilized in conventional layeredphase TFM constructions. In this paper, we investigate the influence of the shape of saddle phase windings and their parameter variations on the output torque productivity. Non-meshed coils evaluated via a finite element method (FEM) to examine the effect of the coil's location within one phase on machine performance. By using meshed coils, the analysis can be extended to inspect the distributions of magnetic field strength as well as current density in the coils. Throughout the study, the influence of design parameters on the output torque for two stator structures, i.e., a laminated and soft magnetic composite (SMC), are evaluated.

• Structural Engineering and Mechanics
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• v.17 no.3_4
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• pp.291-302
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• 2004

In this paper, load monitoring technologies using U-shape Magnetoelastic (EM or ME) sensors have been exploited systemically for the first time. The steel rod to be tested is the Japan 7 mm piano steel rod. The load dependence of the magnetic properties of the piano steel rod was manifested. Two experimental designs of U-shape magnetoelastic sensors were introduced, one with double pick-up concentric coils wound on the rod to be tested, the other with pick-up coil on one yoke foot. The former design is used to derive the correlation of the relative permeability with elastic tension, while the latter is aimed to reflect the stress induced magnetic flux variation along the magnetic circuit. Magnetostatic simulations provide interpretations for the yoke foot sensing technology. Tests with double pick-up coils indicate that under proper working points (primary voltages), the relative permeability varies linearly with the axial load for the Japan 7 mm piano steel rod. Tests with pick-up coil on the yoke foot show that the integrated sensing voltage changes quadratically with the load, and error is more acceptable when the working point is high enough.

• Journal of Power Electronics
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• v.19 no.3
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• pp.625-636
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• 2019

This paper proposes an active leakage magnetic field (LMF) suppression scheme, which uses the dual-transmitter (DT) topology, for EV wireless charging systems (EVWCS). The two transmitter coils are coplanar, concentric and driven by separate inverters. The LMF components generated by the three coils cancel each other out to reduce the total field strength. This paper gives a detailed theoretical analysis on the operating principles of the proposed scheme. Finite element analysis is used to simulate the LMF distribution patterns. Experimental results show that when there is no coil misalignment, 97% of the LMF strength can be suppressed in a 1kW prototype. These results also show that the impact on efficiency is small. The trade-off between LMF suppression and efficiency is revealed, and a control strategy to balance these two objectives is presented.

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.318-326
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• 2009

A simple method for measuring magnetic flux and induced current in magnetic nerve stimulation for urinary incontinence treatment is proposed. Unlike electric nerve stimulation, direct measurement of the induced current in magnetic nerve stimulation is impossible. Since induced currents stimulate nerves or muscles in magnetic nerve stimulation, measuring induced current is very important in validating stimulation efficacy and securing safety. The magnetic flux measuring system is composed of 6 layers with pick-up coils of 7 by 7 in each layer, and the induced current measuring system is composed of 6 layers with 7 concentric circular coils in each layer. The proposed method can be used in the design or performance test of a magnetic nerve stimulator for many clinical applications such as urinary incontinence treatment, activation of peripheral nerves, and transcranial magnetic stimulation.

• Journal of Sericultural and Entomological Science
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• v.31 no.2
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• pp.113-120
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• 1989

A new microsporidia (S85) was isolated from the silkworm, Bombyx mori L. in Suwon, Korea in 1985. The electron microscopic observation of the fine structure of the spore was studied for the characterization of the new microsporidia and its taxonomic position. The sporewall was composed of three different electron dense layers and the spore surface was rouph and wrinkled. The polaroplast has two parts which differed in the arrangement of the lamellae. The polarfilament was isofilar with thirteen coils and it was consisted of eight concentric layers of different electron density. The spore contained a single nucleus and the pansporoblast appeared as a thin ballon-like structure surrounding the spore. The membrane was generally smooth and shown occationally wrinkled.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.1
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• pp.25-34
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• 2017

The concentric dual-buoy Wave Energy Converter (WEC), which consists of external buoy (hallow-cylinder) with toroidal appendage and cylindrical internal buoy within the moon-pool is suggested in this research and its performance in various wave conditions is studied. The Linear Electric Generator (LEG), consisting of a permanent magnet and coils, is used as a direct Power Take-Off (PTO) system. To maximize the electrical energy extracted from the PTO system, the relative heave motions between the dual buoys must be highly amplified by the multiple resonance phenomena of dual-buoy and internal-fluid motions. The high-performance range can be widened by distributing those natural frequencies with respect to the peak frequency of the wave spectrum. The performance of the newly developed dual-buoy WEC was measured throughout the systematic 1:5.95-model test in regular and irregular waves conducted in a wave tank at Seoul National University. The model-test results are also validated by an independently developed numerical method.