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Yamada K.,Saitama University | Yamada K.,Oita University | Isobe Y.,Nuclear Fuel. Ind. | Todaka T.,Oita University | And 2 more authors.
Key Engineering Materials | Year: 2015

The martensitic transformations (MT) in austenite stainless steel (SUS316) were observed by using a sensitive Flux-Gate (FG) sensor just after the magnetizations by the permanent magnet in the terrestrial field. MT in the small deformation range less than 5% elongation, was visualized by the 2-dimensional profile at each position together with the profile of the thickness deformations with an accuracy of several microns. We found the local MT enhancements up to 400[nT] at the positions along the changes of the thickness. In this experiment, the observations of MT were able to avoid the effects of the external fields or of the ac fields which was generated by the gating function in the FG sensor. © 2015 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.

Kai Y.,Oita University | Enokizono M.,Oita University | Kido Y.,Oita Industrial Research Institute
IEEJ Transactions on Fundamentals and Materials | Year: 2013

It is well known that magnetic properties of electrical steel sheets are influenced due to mechanical stress strongly. We have been measured residual stress distribution with a X-ray stress measurement device and clarified not only the tensile and compressive stress but also the shear stress in a rotating machine core. In particular, the influence of the shear stress on the magnetic property has not been reported. We try to develop a new measurement system of vector magnetic property under the shear stress. This paper presents a mechanism to apply the shear stress and the measured vector magnetic property of a non-oriented electrical steel sheet under the shear stress. As these results, the difference of the vector magnetic property of the non-oriented electrical steel sheet was obtained according to the shear stress. © 2013 The Institute of Electrical Engineers of Japan.

Matsuda M.,Future Product Corporation | Shimoji H.,Oita Industrial Research Institute | Shimoji H.,Oita University | Yamada K.,Future Product Corporation | Yamada K.,Oita University
Materials Science Forum | Year: 2016

New applications of nano-scale powders of Si, SiO2 and BaTiO3, etc. have been developed for vacuum sealing, reflectors in LED devices and thermally cooling membranes from metal surface. The optical transparency and good vacuum sealing were formed in baking temperatures as low as 150°C, 1hr by using nano-scale powders of these materials. We show the several applications of capacitors with the material thicknesses between 1 and 10 μm, and show the thermally cooling enhancements in several metals of Al, Fe and stainless steel up to 2.5deg/s in the metal temperature range higher than 50°C. © 2016 Trans Tech Publications, Switzerland.

Tanaka G.,Gunma Museum of Natural History | Taniguchi H.,Oita Industrial Research Institute | Maeda H.,Kyoto University | Nomura S.-I.,Kyoto University
Geology | Year: 2010

Greenish-blue metallic colored fossil elytra of the leaf beetle (Plateumaris sp.) have been discovered in the peat sediment of the middle Pleistocene (ca. 600 ka) Hirabaru Formation, Kyushu, Japan. Scanning and transmission electron microscopy revealed the smooth outer surface of the fossil elytra and five alternating electron-dense and electron-lucent layers in the epicuticle. By applying the matrix method to the epicuticle, three reflective peaks of wavelengths 388 nm, 544 nm, and 656 nm were computed. These peaks correspond to the reflective color observed under white light. Thus, the coloration of the fossils was caused by multilayer reflectors of the epicuticle of the elytra. Pyrolysis-gas chromatography-mass spectrometric analysis revealed that the fossil elytra have preserved some of their original macromolecules (chitin, protein, and amino acids), which are similar to those of a related Holocene species. The high-porosity matrix of the peat contains many fragments of diatoms, indicating the high productivity of the water column but a reducing bottom environment. Slight acidity of the interstitial water also seems to contribute to the preservation of some original macromolecules of fossil insects through geologic time. © 2010 Geological Society of America.

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