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Shimoji H.,Oita Prefectural Organization for Industry Creation | Shimoji H.,Oita University | Todaka T.,Oita University | Enokizono M.,Oita University
Przeglad Elektrotechniczny | Year: 2011

The aim of this study is to measure the distribution of core loss in electrical steel sheets by using a thermographic camera. This paper describes the measurement system and method, along with their underlying principles. Measurement problems are investigated, and the measurement accuracy is determined. The iron loss distributions are presented, as measured under various conditions on vector magnetic measurement equipment.


Ueno T.,Oita National College of Technology | Aihara S.,Nishi Nippon Electrical Wire and Cable Co.Ltd | Gotoh Y.,Oita Prefectural Organization for Industry Creation
Materials Science Forum | Year: 2013

Transcranial Magnetic Stimulation (TMS) is a noninvasive method to cause depolarization or hyperpolarization in the neurons of the brain. The recent research has developed a novel magnetic coil that can generate higher magnetic field than a conventional coil and have converging capability, which would require a larger exciting current. In this research, a thyristor as a switching device was used for high current switching. The thyristor is a device of current drive. The current differences of each circuit in parallel connected thyristors were measured by changing gate voltage and gate rise time. The gate drive characteristic of parallel connected thyristors was also confirmed. © (2014) Trans Tech Publications, Switzerland.


Ohnishi O.,University of Miyazaki | Doi T.,Kyushu University | Kurokawa S.,Kyushu University | Takahashi K.,Mitsui Engineering and Shipbuilding Co. | And 3 more authors.
International Journal of Nanomanufacturing | Year: 2014

The present paper deals with the micro drilling into silicon carbide (SiC) with micro polycrystalline diamond (PCD) drills. Micro PCD drills with a nominal diameter of 300 m were fabricated by wire electrodischarge machining and they were used to drill into SiC test pieces with or without ultrasonic vibration. In the drilling test, performance of drilling into SiC was investigated. As the result of the drilling test, it was possible to make holes with good shape under all conditions. Large feed condition led to large chipping around hole entrance, bad surface roughness of hole wall and a shortened tool life. On the other hand, effects of ultrasonic vibration on chipping, surface roughness of hole wall, chip form and tool life were unclear, but the surface appearance of holes drilled with ultrasonic vibration did not seem to be affected so much by increase of feed. © 2014 Inderscience Enterprises Ltd.


Kutsukake A.,Oita Industrial Research Institute | Kido Y.,Oita Industrial Research Institute | Ikeda T.,Oita Industrial Research Institute | Kanada T.,Oita Prefectural Organization for Industry Creation | Enokizono M.,Oita University
International Journal of Applied Electromagnetics and Mechanics | Year: 2014

A study is carried out based on the evaluation of IEC-standard. Two measurement results on N.O. magnetic steel sheets, one from S-SST (Stress load type single sheet tester developed in our research laboratory), another is from SST based on the IEC standard regulation, are compared and discussed. As a result of the measurements, both magnetization curves coincide mostly, but magnetic power loss determined by IEC method is larger than that achieved by S-SST. The differences between them may be caused by magnetic field strength evaluation for each measurement method, magnetizing current method for IEC-type-SST and H-coil method for S-SST. The effective magnetic path is regulated in IEC but actually this may be variable according to the type of magnetic sheet, the structure of the SST and of applied magnetic field strength. In order to discuss this point, a virtual magnetic path length is introduced by using the applied magnetic field strength. © 2014 - IOS Press and the authors.


Ohnishi O.,Kyushu University | Onikura H.,Kyushu University | Mizue H.,Oita Industrial Research Institute | Kido Y.,Oita Prefectural Organization for Industry Creation | And 2 more authors.
Proceedings of the 10th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2010 | Year: 2010

The present paper deals with the micro drilling into quartz glass with micro polycrystalline diamond drills, hereafter called micro PCD drills. Micro PCD drills with a nominal diameter of 300 μm are fabricated by wire electro-discharge machining, hereafter called wire-EDM. The fabricated drills have various shapes. The fabricated drills are used in the drilling into quartz glass with or without ultrasonic vibration and influences of drill geometry are investigated. As the result, it is found that a certain geometry of drill improves quality of hole entrance and hole wall. © euspen Headquarters.

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