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Papers by Shingo Kanehira

Materials Sciences and Applications, 2021

Recently, under the circumstances of pandemic of COVID-19 much attention has been paid to titaniu... more Recently, under the circumstances of pandemic of COVID-19 much attention has been paid to titanium dioxide TiO2 as bactericidal agent; however, conventional TiO2 requires ultraviolet radiation or visible light to exercise its photocatalytic properties and its induced antimicrobial activity. In order to expand its applications directed at wide civil life, antibacterial TiO2 being usable under dark conditions has been demanded. The present paper describes the powder characterization of newly developed potassium K and phosphorous P co-doped nanometer-size anatase TiO2 powders using X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM & TEM), Brunauer-Emmett-Teller method (BET), fourier-transform infrared spectroscopy (FT-IR), X-ray absorption fine structure (XAFS), electron spin resonance (ESR) and chemiluminescence (CL). It was found for the first time that thus prepared anatase TiO2 could submit much reactive oxygen species (ROS) even in the dark, which has c...

IOP Conference Series: Materials Science and Engineering, 2011

We have succeeded in precipitation of silicon nanoparticles inside silicate glass containing Al m... more We have succeeded in precipitation of silicon nanoparticles inside silicate glass containing Al metal film using femtosecond laser irradiation. The Al-inserted sandwiched glass was fabricated by direct bonding. Raman spectra indicated that silicon particles were formed at the interface between the glass and the Al film after the fs laser irradiation. In addition, the crystallinity of silicon particles was dramatically

SiAlON ceramics were successfully produced from indus-trial wastes such as silicon sludge and alu... more SiAlON ceramics were successfully produced from indus-trial wastes such as silicon sludge and aluminum dross by the nitriding combustion process. The silicon oxynitride as one phase in the sialons system was synthesized from desert sand as well. The nitriding combustion as an energy saving and recycling process, powder synthesis of SiAlONs, mechanical, thermal and chemical properties of the sintered products, and potential applications are reported.

SiAlON ceramics were successfully produced from industrial wastes such as silicon sludge and alum... more SiAlON ceramics were successfully produced from industrial wastes such as silicon sludge and aluminum dross by the nitriding combustion process. The silicon oxynitride as one phase in the sialons system was synthesized from desert sand as well. The nitriding combustion as an energy saving and recycling process, powder synthesis of SiAlONs, mechanical, thermal and chemical properties of the sintered products, and potential applications are reported.

Femtosecond laser is a perfect laser source for materials processing when high accuracy and small... more Femtosecond laser is a perfect laser source for materials processing when high accuracy and small structure size are required. Due to the ultra short interaction time and the high peak power, the process is generally characterized by the absence of heat diffusion and, consequently molten layers. Various induced structures have been observed inside glasses after the femtosecond laser irradiation. Here, we report the refractive index change, space-selective valence state manipulation of active ions and precipitation control of nanoparticles by a femtosecond laser in glasses. We have recently observed the three-dimensional nanostructuring such as a nano-grating and a nano-void inside a glass material by the single laser beam irradiation. The self-organized sub-wavelength periodic nanostructures are created by via a pattern of interference between the incident light field and the electric field of the bulk electron plasma wave. The mechanisms of the observed phenomena were also discussed. Furthermore, we observed the space-selective structural-phase transformation from diamond to amorphous structure which has electrically conductive property.

Journal of the Ceramic Society of Japan, 2011

An ¡-Al 2 O 3 bicrystal doped with Cr 3+ was fabricated by diffusion bonding at high temperatures... more An ¡-Al 2 O 3 bicrystal doped with Cr 3+ was fabricated by diffusion bonding at high temperatures. It was found that a ruby phase with approximately 200 nm thickness was formed along the grain boundary. This thin phase shows Cr 3+ :Al 2 O 3-induced luminescence, confirmed by confocal micro-luminescence spectroscopy.

Smart Materials IV

We have fabricated silicon structure in silicate glass prepared with metallic aluminum in the sta... more We have fabricated silicon structure in silicate glass prepared with metallic aluminum in the starting material, using femtosecond laser irradiation and subsequent annealing. Small Si-rich structures such as oxygen-deficiency (O-deficiency) defects or Si clusters transform into nano-sized Si particles by the focusing irradiation of the laser. Then the Si-rich structures grow into micro-size particles due to the thermite reaction promoted by heat treatment. We determine the effect of focused laser pulse on the Si deposition process by using a time-resolved transient lens method with a sub-picosecond laser pulse. Localized high-temperature, high-pressure, and the generation of shock waves appear to be very important in forming the Si-rich structures that ultimately grow into Si particles. The diffusion of oxygen by shock waves and the existence of Al-rich structures help form Si-rich structures as Si-O bonds continuously break under high temperature. The focusing irradiation of femtosecond lasers is very useful for fabricating Si structures inside glass.

Journal of the Society of Materials Science, Japan

A three-dimensional photonic crystal with a diamond structure made of epoxy lattices incorporatin... more A three-dimensional photonic crystal with a diamond structure made of epoxy lattices incorporating TiO2-SiO2 composite ceramics particles were fabricated by stereolithography. The transmission spectra of microwaves with TE10 mode through the photonic crystal showed the existence of a complete photonic band gap in the frequency range of 14.3-15.8GHz. An air cavity defect with a rectangular shape was introduced into the photonic crystal by removing three or five unit cells aligned in the diamond structure. The transmission amplitude of microwave through each defect structure showed the existence of a resonant mode inside the photonic band gap. A planar waveguide with the diamond structure, which contains an air cavity layer, was also formed by using stereolithography. It showed a transmission of a resonant mode at 15.4GHz.

Journal of Asian Ceramic Societies, 2013

Mechanism of aluminum powder corrosion in calcium hydroxide solutions was investigated via variou... more Mechanism of aluminum powder corrosion in calcium hydroxide solutions was investigated via various analyses of residues after its hydrolysis reaction and pH change of the solutions to control the release of hydrogen gas. It was revealed that the reaction with a release of hydrogen gas consisted of katoite formation and hydration of aluminum. The katoite formation, which is progressed by the reaction among calcium ion, aluminum hydroxide anion (Al(OH) 4 −), and water molecules at the first step, is important for the promotion of aluminum corrosion and moderate release of hydrogen gas.

Transactions of J W R I, Dec 1, 2010

Journal of the Ceramic Society of Japan, 2016

Micro-tubular SOFCs (Solid Oxide Fuel Cells) with internal conduction layer were fabricated by co... more Micro-tubular SOFCs (Solid Oxide Fuel Cells) with internal conduction layer were fabricated by controlling the shrinkage of the inner anode layer to avoid the delamination or breakage of the cell during sintering. In order to fabricate these cells, pre-sintering of anode tubes were examined in a temperature range of 10001350°C. Micro close end tubular cells were successfully prepared by using this pre-sintering at 1100°C. The micro-tubular cells with close end show good tolerance to repeating thermal cycles due to their unique shape. Because of one end connection, the polarization of them was larger than the common tubular cells with two end connection and needed to be improved, which was solved by the application of internal porous conduction layer. As demonstrated by this work, maximum power density of 0.6 W/cm 2 at 600°C was obtained after application of a thin nickel conductive layer, which was as thin as 20¯m.

Smith/Environmental, 2006

Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XVII, 2012

ABSTRACT When femtosecond laser pulses are focused inside a single crystal, anisotropic structura... more ABSTRACT When femtosecond laser pulses are focused inside a single crystal, anisotropic structural changes such as dislocation and cleavage occur along specific orientations. It can be interpreted that the anisotropic structural changes should be induced by transient stress after photoexcitation, such as a thermal stress and stress wave. To elucidate the mechanism of the laser induced structural changes inside crystals, we developed a novel time-resolved polarization imaging system, in which circularly polarized laser pulse was used as a probe light. The system enabled us to observe laser-induced transient stress distribution as well as the orientation after focusing fs laser pulses inside MgO and LiF single crystals. Based on the observation, we elucidated the relation between laser-induced transient stress distribution and anisotropic structural change inside the crystals.