Shohei Oda

Observation of Subsurface Structures by Scanning Laser Photoacoustic Spectroscopy

Aiming at the detection of the subsurface structure of the material, a new technique using a piezoelectric transducer (PZT) as a photoacoustic detector is presented and discussed. Aluminum foils with a groove under the surface were used as samples and the groove was detected by measuring the amplitude or the phase angle of the photoacoustic signal. By the use of a relatively high modulation frequency, a new elastic image as well as thermal image have been obtained.

Nondestructive Determination of the Degree of Saponification Using Concentration Depth Profiling of Functional Groups by FT-IR/ATR Spectroscopy

Concentration depth profiling of functional groups using FT-IR/ATR spectroscopy has been applied to the nondestructive determination of the degree of saponification. A two-layered film, which had acetyl groups in its surface layer distributed inhomogeneously in the depth direction, was prepared. The dependence of its FT-IR/ATR spectra on incident angles was measured. The degree of saponification was determined on the basis of the concentration depth profile of the acetyl groups obtained from the angular dependency. The results obtained showed good agreement with micro FT-IR and neutralization titration results. This method is judged able to determine functional groups within the range of a few micrometers from the sample surface.

Effects of several experimental parameters on the relative sensitivity factors in spark-source mass spectrometric analysis of steel

Abstract The effects of spark gap, sample electrode size, spark technique, spark position, and energy-pass bandwidth of the ion beam, on the relative sensitivity factors in analysis for trace elements in steel by spark-source mass spectrometry have been investigated by means of electrical-detection, peak-switching techniques. The effects of spark gap and spark position are of the greatest importance. The energy distributions of both matrix and impurity ions were measured. For several elements, changes in spark position produced corresponding changes in the distribution of ion energies. These changes of energy distribution were partly responsible for variations in relative sensitivity factors with changing spark position.

Simultaneous determination of oxygen and nitrogen in iron and steel by spark-source mass spectrography.

A conventional technique has been developed for the simultaneous determination of oxygen and nitrogen in iron and steel by spark-source mass spectrography in the range of 2-400 ppm with a precision of 20%. The instrumental background can be reduced by cryosorption pumping and sample cooling. The adsorbed oxygen on the surface of the sample is easily eliminated by presparking to exhaust the surface concerned. A difference in matrix effect in oxygen determination was observed between iron and steel.

Temperature-Dependent XAFS Study on AgBr1-xIx Solid Solution

Local structures of rock salt type AgBr1-xIx solid solutions with x varying from 0.07 to 0.4, substances interesting from both viewpoints of crystal structure and excellent properties as a photographic material, have been investigated by EXAFS analysis of three sets of spectra, i.e., I K-edge, Br K-edge and Ag K edge, at various temperature from 10K to room temperature. The Br-Ag and I-Ag interatomic distances in the solid solution were different from each other and deviated from the average Ag-(Br,I), or virtual crystal, distance determined from X-ray diffraction at any temperature. The iodide content x dependence of I-Ag and Br-Ag interatomic distances changed with temperature. At low temperature the I-Ag and Br-Ag distances increased with increasing the iodide content, whereas at room temperature they did not exhibit significant change with composition. This suggested that the bonding nature of the AgBr1-xIx solid solution is rather ionic at low temperature, while it is rather covalent at room temperature.

LIQUID MEMBRANE PH ELECTRODE BASED ON AMINE OXIDE OR PHOSPHINE OXIDE AS THE NEUTRAL CARRIERS

New H + -selective ion carriers suitable for imprenating in liquid membrane as the active component of the pH electrodes are described. It has been found that lipophilic amine oxide and phosphine oxide behaved as neutral carrier for proton with excellent selectivities at basic side or acidic side, respectively. The observed ion selectivities for the new electrodes utilizing the proton carriers were superior to those of previously reported pH-sensitive liquid membrane electrodes