Spectroscopic study of polytoluidines in the UV-visible and IR regions

Electropolymerization of o-toluidine(o-methylaniline) and m-toluidine was carried out in acidic aqueous solution, and UV-visible and IR spectra of the resulting polymer films were obtained at various electric potentials and pHs. In Na₂SO₄ aqueous solution, poly(o-toluidine) gave considerably different UV-visible spectra from polyaniline, whereas, in HCl (pH ～ 0), the spectra of poly(o-toluidine) changed in the same way as polyaniline when the potential was varied. This spectral change depended also on counterion. This suggests that the intermediate state (radical cation) of poly(o-toluidine) is unstable in a neutral solution especially when a large counter ion exists, which is contrast to polyaniline. The dependency of the FT-IR spectra of poly(o-toluidine) on the potential and pH supported also the above result of UV-visible spectra. From both UV-visible and IR spectra under various conditions, it was found that o-toluidine and m-toluidine give the same polymer.     

The variation of greenhouse gas emissions from soils of various land-use/cover types in Jambi province,Indonesia

We measured fluxes of three greenhouse gases (N₂O, CO₂O and CH₄) from soils of six different land-use types at 27 temporary field sites in Jambi Province, Sumatra, Indonesia. Study sites included natural and logged-over forests; rubber plantation; oil palm plantation; cinnamon plantation; and grassland field. The ranges of N₂O, CO₂ and CH₄ fluxes were 0.13–55.8 gN m-2h-1; 1.38–5.16 g C m-2d-1; –1.27–1.18 mg C m-2d-1, respectively. The averages of N₂O, CO₂ and CH₄ fluxes at 27 sites were 9.4 gN m-2h-1,3.65 g C m-2d-1, –0.45 mg C m-2d-1, respectively. The values of CO₂ and CH₄ fluxes were comparable with those in the reports regarding other humid tropical forests, while the N₂O flux was relatively lower than those of previous reports. The N₂O fluxes in each soil type were correlated with the nitrification rates of soils of 0–5 cm depth. In Andisols, the ratio of the N₂O emission rate to the nitrification rate was possibly smaller than that of the other soil types. There was no clear relationship between N₂O flux and the soil water condition, such as water-filled pore space. Seventeen percent of CH₄ fluxes were positive; according to these positive fluxes, we did not find a good correlation between CH₄ uptake rate and soil properties. Although we performed a chronosequence analysis to produce some hypotheses about the effect of land-use change by a limited amount of sampling at one point in time, further tests are required for the future.     

2.5kA/1.2kV两单元IGBT模块

介绍一种工业用2.5 kA/1.2 kV两单元IGBT模块.在该大电流器件中,P端到N端的内部连线电感非常小.半导体硅片的巧妙布局有效地提高了模块的散热能力,采用铝底板直接连接绝缘基板来提高热循环能力.对于这种底板面积较大的器件,为了获得更好的底板和散热片之间的热接触.底板被分成几段.2.5 kA/1.2 kV两单元IGBT模块的封装同样适用于1.8 kA/1.7 V两单元IGBT模块.     

Depth sizing of partial-contact stress corrosion cracks from ECT signals

A partial-contact stress corrosion crack (SCC) is electrically modeled as a crack region with non-zero conductivity in eddy current testing (ECT). This partial-contact effect is excluded by an optimally designed crack-conductivity-insensitive depth characterization signal function (DCSF), and consequently the master curves obtained from electric-discharge machining (EDM) notches can be utilized directly in the depth sizing of SCCs. Furthermore, a crack conductivity independent artificial neural network (ANN) is constructed so that the entire depth profile can be reconstructed regardless of the crack conductivity. These two approaches are numerically validated and applied to the characterization of SCCs in SUS304 from measurement ECT signals. The average depth of each SCC is fast estimated from the DCSF, and the detailed depth profile is reconstructed from ANN. The ECT depth-sizing results show reasonable agreement with UT-TOFD measurement.     

Effect of glycerol on micro/nano structures of catalyst layers in polymer electrolyte membrane fuel cells

Effect of glycerol in catalyst ink on the micro/nano structures of polymer electrolyte membrane fuel cells (PEMFCs) catalyst layers was investigated. Catalyst layers were fabricated by the decal method for various mass ratios of glycerol to carbon in the catalyst ink r_gc (=m_g/m_c) from 0 to 20, and thus change the micro/nano structures of catalyst layer. The structures were evaluated by measuring the pore size with a mercury porosimeter and by observing the surface with a field emission scanning electron microscope (FE-SEM). At r_gc < 5, although the residual glycerol was almost zero, the cell performance decreased with decreasing r_gc, suggesting that the structure of the catalyst layers significantly depended on r_gc. At r_gc > 5, the remaining glycerol was proportional to r_gc. Because remaining glycerol blocks the pores and reduces the reaction sites, the cell performance decreased with increasing r_gc. If the remaining glycerol is removed by steam water, the performance is improved to the same level of the maximum performance for not steamed MEAs.     

Isolation, identification and determination of a magenta subsidiary colour in Food Blue No. 1 (Brilliant Blue FCF)

A magenta subsidiary colour was isolated from commercial Food Blue No. 1 (B-1; Brilliant Blue FCF). The absorption maximum for this subsidiary colour at 580nm is outside of the range of 614-628nm found for other subsidiary colours and m,m -B-1. On the basis of MS and NMR analyses, the structure of the subsidiary colour was elucidated as the disodium salt of 2-[[4-[Nethyl-N-(3-sulphophenylmethyl)amino]phenyl][4-oxo2,5-cyclohexadienylide acid. HPL C analyses revealed that 24 batches of commercial Food Blue No. 1 (three manufacturers) contain 0.1- 0.8% (average: 0.5% ) of the magenta subsidiary colour.     

Preparation of Dense BaTiO3 Ceramics with Submicrometer Grains by Spark Plasma Sintering

Dense BaTiO₃ ceramics consisting of submicrometer grains were prepared using the spark plasma sintering (SPS) method. Hydrothermally prepared BaTiO₃ (0.1 and 0.5 µm) was used as starting powders. The powders were densified to more than similar/congruent95% of the theoretical X-ray density by the SPS process. The average grain size of the SPS pellets was less than similar/congruent1 µm, even by sintering at 1000-1200°C, because of the short sintering period (5 min). Cubic-phase BaTiO₃ coexisted with tetragonal BaTiO₃ at room temperature in the SPS pellets, even when well-defined tetragonal-phase BaTiO₃ powder was sintered at 1100° and 1200°C and annealed at 1000°C, signifying that the SPS process is effective for stabilizing metastable cubic phase. The measured permittivity was similar/congruent7000 at 1 kHz at room temperature for samples sintered at 1100°C and showed almost no dependence on frequency within similar/congruent10⁰-10⁶ Hz; the permittivity at 1 MHz was 95% of that at 1 kHz.     

Decoding of depth and motion in ambiguous binocular perception

We have shown previously that random dots with an interocular time delay (ITD), the time difference of the onset of dots between the two eyes, yield both apparent depth and motion, although depth and velocity are covariant and, thus, ITD is inherently ambiguous. The depth of random dots with ITD was proportional to ITD, suggesting that the visual system assumes a constant velocity of the dots and determines depth on the basis of this constant velocity. We performed psychophysical experiments to investigate whether subjects perceive a constant velocity with a variety of ITDs in random dots aligned along a single vertical line that ensures neither apparent motion nor accidental disparity between the dots. The results showed that subjects perceive a constant velocity for a variety of ITDs with simultaneous perception of depth in proportion to ITD, indicating the priority of depth over velocity in ambiguous binocular perception derived from ITD.     

Development of micro-beam NRA for hydrogen mapping: Observation of fatigue-fractured surface of glassy alloys

A micro-beam NRA system by means of a resonant nuclear reaction of ¹H(¹⁵N, αγ)¹²C has been developed at the beam line in MALT, University of Tokyo. The beam optics was analyzed in terms of the phase diagram. By carefully suppressing the spherical aberration of the final quadrupole magnetic lens, the ¹⁵N beam at the energy of 6.4 MeV was focused on targets with a size of 17 μm × 30 μm. For the precise positioning of the sample and beam spot, a combination of the mirror and optical microscope was adopted, so that the hydrogen concentration can be measured at a desirable position of the sample. With this new system, the hydrogen concentrations of fatigue-fractured surfaces of glassy alloys were determined from the viewpoint of the hydrogen embrittlement: Zr₅₀Cu₃₇Al₁₀Pd₃ and Zr₅₀Cu₄₀Al₁₀. Depth-resolved two-dimensional (2D) mapping of hydrogen concentration was performed in the area of 3 mm × 3 mm with an in-plane resolution of 150 μm. The maps taken at three different depths revealed that the hydrogen concentration is higher in the fatigue-fractured regions in both samples.