Akihiko Fukunaga 교수

To consider an appropriate evaluation method for hydrogen compatibility, slow strain rate tensile (SSRT) tests were conducted on high strength piping materials, cold-worked type 316 austenitic stainless steel (SUS316CW) and iron-based superalloy A286, used in hydrogen stations for two years. SUS316CW, used at room temperature in 82 MPa gaseous hydrogen, contained 7.8 mass ppm hydrogen. The SSRT test of SUS316CW was conducted in nitrogen at -40 °C. The fracture surface showed dimples, and no hydr

Ni–P alloy has been used as a protective coating for mechanical parts, a surface material for electronic parts, and an electrocatalyst for water electrolysis. Ni–P alloy electrodeposition was performed by adding H3PO3 to Watts baths under four different types of pulse current conditions and compared with direct current (DC) electrodeposition. When the peak current density was kept constant and the off time was extended, the P content increased, and the current efficiency decreased. When the off

To investigate the evaluation method of hydrogen compatibility of A286 superalloy in high pressure hydrogen gas, SSRT tests of hydrogen-charged specimens were conducted at ambient temperature at various strain rates. The relative reduction in area (RRA), one of the ductility parameters, was determined. The hydrogen content in the hydrogen-charged specimen was the same as the equilibrium hydrogen content on the specimen surface at 150 °C in 70 MPa hydrogen gas. The strain rate dependence of RRA w

To investigate the effects of a high-pressure hydrogen environment in the elastic and plastic deformation regions, we performed slow strain-rate tensile tests of iron-based superalloy A286 at 150 °C by switching the atmosphere from 70 MPa hydrogen to air during the tests. The relationship between the nominal strain exposed to a hydrogen environment and the relative reduction in area (RRA) revealed that in the plastic deformation region, the RRA value decreased gradually depending on the nominal

Dehydrogenation of methylcyclohexane (MCH), a hydrogen carrier, is investigated using a solid oxide fuel cell (SOFC). When an SOFC is operated with a cell temperature of 420 °C and a current density of 16 mA cm−2, toluene and benzene, the products of MCH’s dehydrogenation reaction, are observed, with a molar ratio of 94:6. When the cell is operated at 490 °C and 90 mA cm−2, in addition of toluene and benzene, 1,4-dioxane is formed at a molar ratio of >86%, indicating an oxidative dehydrogenation

To investigate dependence of strain rate of tensile test for iron-based superalloy SUH660 (A286), tensile tests were conducted for the specimens in 70 MPa hydrogen gas and air at 150°C. Nominal stress-nominal strain curve of each strain rate in 70 MPa hydrogen gas showed same behavior to maximum load via yield point in comparison with that in air, however, each elongation at breaking point in 70 MPa hydrogen was a little shorter than that in air. The values of tensile strength didn’t depend on t

NbC nanorods and nanoparticles have been synthesized using a vapor-solid reaction path starting with carbon nanotube precursors. Their structures are studied using XRD, TEM, and HRSEM. Their superconducting properties of nanoparticles were also characterized using a SQUID magnetometer. For reactions at lower temperatures, NbC nanorods (10∼20 nm) which replicate the precursor carbon nanotubes are observed. For reactions at higher temperature, coarsened NbC nanoparticles (100∼500 nm) are observed

Thin films of Al and Al-Cu were made by vapor deposition under various conditions, and their differential double layer capacities and polarization resistances were rapidly measured in Cark Lubs buffer solution (pH 7.2). The films were then compared with other vapor deposited films and bulk metals.It was found that since the measured values of polarization resistance clearly represented the surface conditions of the films, they were effective in evaluating the corrosion rate.

3-Aminopropyl(methyl)phosphinic acid (APMP), a potent agonist of mammalian GABAB receptors, caused prostration in houseflies (Musca domestica L.) on injection into their thoraces, with an ED50 value of 0.42 microgram/fly. The 48-h LD50 values of APMP were estimated to be 0.45 and 5.6 micrograms/fly in the presence and absence of piperonyl butoxide, a mixed-function oxidase inhibitor, respectively. Analogues of APMP, bearing a longer or shorter side chain by a CH2 unit, or a phenyl group in the p