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The pulsed-laser deposition (PLD) technique was used to grow high TC superconducting YBa2Cu3O7-δ (YBCO) films on both virgin and ion-bombarded yttria-stabilized zirconia (YSZ) substrates. To pattern high TC films for device applications, the ion milling technique is often used to turn virgin YSZ substrates into ion-bombarded substrates. Multilayered processes require the growth of high TC films on these ion-bombarded substrates. The purpose of this work was to investigate the growing conditions for these two kinds of substrate surfaces. We found that high quality 0° in-plane orientation films can be grown on either substrate when the growth temperature is about 810 °C. The thin film grown at this temperature has TC of about 90.3 K and JC of about 4×106 A cm-2 at 77 K. On virgin substrates, the in-plane orientations of YBCO films grown within the temperature range of 790–730 °C exhibit a mixture of 0° and 45° domains. As the growth temperature decreases, the dominant orientation shifts gradually from 0° to 45°. On the other hand, on ion-bombarded YSZ substrates, the in-plane orientation of YBCO films grown within the same temperature range shows that the 45° domain is more prominent. Furthermore, 9° subpeaks appear around the 0° peak on ion-bombarded YSZ substrates. At a lower growth temperature of around 690 °C, only the 45° domain exists on the virgin substrate, while a small amount of 0° domain is present with the majority of 45° domain on the ion-bombarded substrate. The TC and JC of the films grown at around 690 °C on virgin substrates are as good as films grown at high temperatures, despite the difference in the in-plane orientations. [ABSTRACT FROM AUTHOR]

Doppler flow velocity-time waveforms of the middle cerebral arteries at their origin from the internal carotid arteries were obtained serially on 14 patients to determine the alterations of these waveforms with gestational age. Satisfactory recordings were obtained from all patients. The middle cerebral artery waveforms demonstrated a typically biphasic pattern with continuing forward flow in diastole. The peak systolic to end-diastolic ratio (A/B ratio) showed a progressive and significant decline from 6.89 +/- 1.48 at around 25 weeks to 4.23 +/- 0.67 at term. Elevation of diastolic velocities and diminished A/B ratio in the middle cerebral arteries were noted in four fetuses, in whom severe antepartum compromise was diagnosed. The ratio also appeared to decrease with worsening of fetal condition. Because the fetus compensates for hypoxia by increasing blood flow to the brain, Doppler middle cerebral artery waveforms may permit evaluation of fetal compromise and hypoxia.