Hidehito Obayashi

Perovskite-type oxides as ethanol sensors☆

Some of the perovskite oxides such as (Ln, M) BO3 (Ln = lanthanoid element, M = alkaline earth metal, and B = transition metal) are good oxidation catalysts. When the compounds are maintained at 150–400°C and a trace amount of reducing gas (such as ethanol or carbon monoxide) in air comes in contact with the oxides, the resistivity of the oxides increases in proportion to the gas concentration with a comparatively short response time, and it recovers to the initial value when the gas is removed. A new type of quantitative ethanol sensor making use of this property is described.

Some Crystallographic, Electric and Thermochemical Properties of the Perovskite-Type La1-xMxNiO3(M: Ca, Sr and Ba)

The perovskite-type compounds La1-xMxNiO3 (M: Ca, Sr and Ba) were synthesized and their crystallographic, electric and thermochemical properties were investigated. The regions of perovskite formation were determined. The solubility limits or alkaline earth elements into La sites are around 5% for Sr and Ba, and less than 1% for Ca. The charge compensation of divalent ion substitution into a trivalent La ion site takes place by the formation of oxygen ion vacancies. Lanthanoid elements other than La did not form perovskite-type oxides. The compound LaNiO3 undergoes a rhombohedral-cubic transition at 940?C and decomposes above 1120?C. Resistivity of LaNiO3 is 9?10-3 ?cm at room temperature and increases as the temperature is raised.

Composition dependence of lithium ionic conductivity in lithium nitride-lithium iodide system

Abstract Two minima in the lithium ionic conductivity vs. composition curve in the lithium nitride-lithium iodide system are observed at Li 5 NI 2 and Li 7 N 2 I. It is shown that ionic conductivity minimum at the stoichiometric Li 5 NI 2 is caused by the increase in the lithium ion concentration.

New fast lithium ionic conductor in the Li3NLiILiOH system

Abstract The electrical properties of Li 3 NLiILiOH (1:2:x molar ratio) compounds are investigated. These quasi-ternary compounds have a cubic crystal structure similar to Li 5 NI 2 . The Li 3 NLiILiOH (1:2:0.77) compound has a conductivity of 0.95 × 10 −1 (S/m at 25°C with an activation enthalpy of 24.6 (kJ/mol). All the compounds investigated are predominantly ionic conductors. The electronic transference number is smaller than 10 −5 and the decomposition voltage of these compounds is about 1.6V at 25°C.

Soft x‐ray spectral characterization of resist polymer using synchrotron radiation

Soft x‐ray absorption spectra and spectral sensitivity of x‐ray resist, poly‐2‐methylpentene‐1‐sulfone, are studied using synchrotron radiation. Shape resonance around the S2p edge and chemical shift among C1s levels are observed in the absorption spectra. The degradation efficiency of the resist is found to vary with incident photon wavelength.

Performance of cylinder type high temperature solid electrolyte fuel cell

Abstract Performance of the cylinder type high temperature fuel cell was calculated on the basis of fuel flow. Fuel composition change, output current, cell length, and electrolyte and/or electrode resistance were explicitly taken into account. Fuel consumption profile, current dinsity distribution, and potential profiles in the electrodes were numerically calculated. From these calculations, it was evident that the cell length is the most important factor in realizing a uniform current density distribution in the cell. A model stack comprised of 2 cm long 10 unit cells connected in series using Ce1−xGdxO2−x/2 electrolyte and LaCoO3 cathode operating at 750°C gives a power density of 220 mW/cm2.

In celebration of the 60th anniversary of Journal of Electron Microscopy

Congratulations on the 60th anniversary of the Journal of Electron Microscopy (JEM). Recollecting the history of Hitachi electron microscopes, I would also like to express our gratitude at this time. We at Hitachi have walked together with the history of Japanese electron microscopes and microscopy. Stimulated by Ruska’s invention of an electron microscope surpassing the resolution of optical microscopes, development of electron microscopes in Japan was started by members of the 37th subcommittee of the 10th committee of the Japan Society for the Promotion of Science in 1939. Hitachi was one of the original members of the subcommittee. K. Kasai, one of the organizers of the subcommittee, moved from the National Research Institute to Hitachi in 1939, as he was eager to make electron microscopes, and thought his ambition could only be fulfilled in the industry. Bunya Tadano moved to Hitachi following Kasai in 1940, and they together developed the first Hitachi transmission electron microscope (TEM) model HU-1 in 1940. In 1942, the Hitachi Central Research Laboratory (HCRL) was established. In the same year, Hitachi delivered the first Japanese commercialized TEM model HU-2 to Nagoya Imperial University just at the height of the Second World War. Although difficulties caused by the war became harder, research and development activities were continued even during air raids with the prototype microscope surrounded by piles of sandbags. Information from foreign countries was shut out completely, but original technologies were incubated. After the war was over, developments accelerated. In 1953, the first export of Hitachi TEM was accomplished and in 1958 the model HS-6 was awarded Grand Prix in the Brussels Exposition. In 1957, J. W. Menter took the first crystal lattice image of Pt-phthalocyanine with a lattice space of 1.19 nm. Challenges to break the resolution record were made by many researchers. T. Komoda of HCRL intensively devoted himself to resolution record competition. In 1963, Komoda took 0.235 nm lattice fringes of Au(111) after years of trials and errors of improving high-voltage stability, mechanical robustness, specimen preparations and imaging techniques with 100 kV TEMs. He took a half-spacing image of Au(111) in 1966. Competition continued and Komoda’s younger colleagues, T. Matsuda, took 0.062 nm fringes of Ni(220) half-spacing with 150 kV TEM equipped with the field emission (FE) gun in 1978 and T. Kawasaki took 0.049 nm spacing of Au(33−7) in 2000 using a 1 MV FE-TEM. To pursue resolution, ultrahigh-voltage electron microscopes (HVEMs) with an accelerating voltage of 500 kV were developed at the HCRL with Nagoya University from 1961 and then transferred to Naka works. Voltage was raised higher. In 1970, a 3 MV HVEM HU-3000 was installed in Osaka University. The world’s highest voltage of 3.5 MV HVEM H-3000 was installed in the same university in 1995. Technologies obtained through developing HVEM were transferred to 200 kV, 300 kV TEM and many other charged particle applied instruments. Hitachi’s scanning electron microscope (SEM) development was started in the early 1960s and the first commercialized SEM HSM-2 was released in 1969. A breakthrough in SEM performance was realized by the FE gun technologies, which have 1000 times higher brightness compared with that of thermionic guns. In the 1960s, Albert V. Crewe, University of Chicago, developed the FE electron gun. His group reported successful observations of single individual atoms of uranium and thorium with their FE-STEM. HCRL started to study cold field emission-STEM in 1968. Hitachi invited Professor Crewe to Naka works as a consultant in 1970, and started developing FE-SEM. HCRL also contributed to improving the stability and reliability of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Journal of Electron Microscopy 60(Supplement 1): S283–S286 (2011) doi: 10.1093/jmicro/dfr046

Soft X-Ray Spectral Characterization Of Resist Using Synchrotron Radiation

Soft X-ray absorption spectra and spectral sensitivity of X-ray resist are studied using synchrotron radiation. A measurement technique for spectral sensitivity named X-ray Excited Ion Mass Analysis is newly developed. Spectral sensitivity is evaluated from the fragment yield of the decomposed resist during exposure to monochromatized synchrotron radiation. Using this technique, the spectral sensitivity of poly-2-methylpentene-1-sulfone is measured. The sensitivity is found to be enhanced at shorter wavelengths despite a low absorption coefficient.

Shorter-wavelength lithography utilizing MRS-type negative resists

Abstract New negative photoresists, called MRS-type resists, are successfully applied to deep-UV 1:1 projection printing and 365 nm 10:1 reduction projection printing. The MRS-type resists are characterized by intense absorption of exposure light and absence of swelling in aqueous developer solutions. They resolve steep profile submicron images in a 1.0 μ thick film. They are not adversely affected by reflected light from water surfaces. In order to use MRS-type resists with broader development latitude, optimizing the extent of light absorption is important because the resist profiles strongly depend on development conditions due to increasing solubility towards the resist bottom.

Spectral sensitivity of resist by x‐ray excited ion mass analysis

A measurement technique of spectral sensitivity for x‐ray resist is developed. Sensitivity is evaluated from the yield of gaseous fragment of resist during exposure to monochromatized synchrotron radiation. Using this technique named x‐ray excited ion mass analysis, the spectral sensitivity of x‐ray resist, poly‐2‐methylpentene‐1‐sulfone, is evaluated. The sensitivity is found to be enhanced at shorter wavelengths despite a low absorption coefficient. This measurement technique promises to improve the spectral sensitivity analysis in the soft x‐ray region.