Time-resolved X-ray Diffraction Techniques Research Articles

Time-resolved X-ray diffraction studies of frog skeletal muscle isometrically twitched by two successive stimuli using synchrotron radiation.

In order to clarify the delay between muscular structural changes and mechanical responses, the intensity changes of the equatorial and myosin layer-line reflections were studied by a time-resolved X-ray diffraction technique using synchrotron radiation. The muscle was stimulated at 12-13 degrees C by two successive stimuli at an interval (80-100 ms) during which the second twitch started while tension was still being exerted by the muscle. At the first twitch, the intensity changes of the 1.0 and 1.1 equatorial reflections reached 65 and 200% of the resting values, and further changes to 55 and 220% were seen at the second twitch, respectively. Although the second twitch decreased not only the time to peak tension but also that to the maximum intensity changes of the equatorial reflections (in both cases, about 15 ms), the delay (about 20 ms) between the intensity changes and the development of tension at the first twitch were still observed at the second twitch. On the other hand, the intensities of the 42.9 nm off-meridional and the 21.5 nm meridional myosin reflections decreased at the first twitch to the levels found when a muscle was isometrically tetanized, and no further decrease in their intensities was observed at the second twitch. These results indicate that a certain period of time is necessary for myosin heads to contribute to tension development after their arrival in the vicinity of the thin filaments during contraction.

Electrostrictive Tensor Components of PZT-Ceramics Measured by X-ray Diffraction

The electrostrictive tensor components Q11, Q12 and Q44 of Pb0.83Sr0.12Ba0.05 [Zr0.6Ti0.38Nb0.02]O3-ceramic were measured separately above Curie temperature with a time-resolved X-ray diffraction technique. The results were corrected for the influence of ceramic parameters. The corrected values are considered to be the same as single-crystal values. This was proven by comparison of values from measurements on BaTiO3-ceramics with the known values for BaTiO3 singlecrystals. The electrostrictive coefficients of the above mentioned ceramic were measured in a temperature range between 420K (Curie temperature) and 470K. The results were independent of temperature: Q11=3.0·10-2 m4/C2, Q12=-1.6·10-2 m4/C2 and Q44=6.2·10-2 m4/C2. In the ceramic system Pb0.83Sr0.12Ba0.05[ZrxTi0.98-xNb0.02] O3 the electrostrictive coefficients were found to vary linearly with variation of x. Our measurements are compared with those of other authors.

Liquid density meter development

The solidification process in stainless steel welds was analyzed using a time-resolved X-ray diffraction technique. By using an undulator beam and a novel X-ray detector, not only the phase evolution during the solidification process but also the grain structure and liquid reduction during the solidification process were analyzed in the reciprocal lattice space. Furthermore, to estimate the temperature that stimulates stray grain formation, the temperature profile at the centerline of a weld bead was measured by using a radiation thermometer with immersion-type optical fiber.