We have demonstrated that the supercurrent distribution in current-biased YBa2Cu3O7−δ thin films can be obtained by measuring the radiation power of THz electromagnetic pulses excited with femtosecond laser pulses. As the radiation power is proportional to the square of the bias current density at the laser spot position, the two-dimensional current distribution can be obtained from the intensity distribution of THz radiation by scanning the laser spot. The characteristic supercurrent distribution is analyzed by using the critical-state model.

This paper presents a drowsiness detection model that is capable of sensing the entire range of stages of drowsiness, from weak to strong. The key assumption underlying our approach is that the sitting posture-related index can indicate weak drowsiness that drivers themselves do not notice. We first determined the sensitivity of the posture index and conventional indices for the stages of drowsiness. Then, we designed a drowsiness detection model combining several indices sensitive to weak drowsiness and to strong drowsiness, to cover all drowsiness stages. Subsequently, the model was trained and evaluated on a dataset comprised of data collected from approximately 50 drivers in simulated driving experiments. The results indicated that posture information improved the accuracy of weak drowsiness detection, and our proposed model using the driver's blink and posture information covered all stages of drowsiness (F1-score 53.6%, root mean square error 0.620). Future applications of this model include not only warning systems for dangerously drowsy drivers but also systems which can take action before their drivers become drowsy. Since measuring the information requires no restrictive equipment such as on-body electrodes, the model presented here based on blink and posture information can be used in several practical applications.

The coupled equations of the adiabatic-state expansion formulated in the context of the stationary-state scattering theory are examined. The translational factors are introduced in the eikonal approximation through coordinate transformation. The equations are consistent with those of Chen and Watson in that they are free from the spurious long-range interaction even in the absence of the translational factors. The cancellation of the spurious R-' long-range interaction of the 2poU-2pn, rotational coupling in the ( p + , H) system is given as an example. The effect of the translational factor on the channel coupling interaction is discussed.where yn is the electron mass and Y is the position vector of the active electron from the centre of mass of the atomic mass centres. The 'translation' factors are not unique and may be replaced by functions which assume the exponential form of(l.l) in the separated atom limit.The difficulties with the adiabatic state of course also appear in the coupled equations formulated in the stationary-state scattering theory. Here it can be shown that the 8 Visitor under the Multinational Project on Physics of the Organization of American States (OAS). Permanent address:

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We studied the optical creation and modulation of magnetic flux quanta in a Y&,CU,O,~ thin film loop by observing terahertz emission excited with femtosecond laser pulses. The magnetic flux is created and modulated in the loops with a polarity controlled by means of optical supercurrent modulation. The results suggest a possible application of the superconductive loop as an optical flux-trap memory for the detection and storage of the femtosecond optical signals. The mechanism for the creation of the magnetic flux is discussed in relation to the current distribution in the loop.

We proposed a multi-pass second harmonic generation scheme in which condensed fundamental light passed through a nonlinear crystal many times. The multi-pass scheme was realized by using a wide periodically-poled MgO:LiNbO3, concave mirrors and condensing optics. The total wavelength conversion efficiency of the multi-pass scheme was increased because non-converted fundamental light which had passed through the nonlinear crystal was re-injected and condensed into the nonlinear crystal and converted. Moreover the total temperature tolerance of the multi passes was widened because the fundamental beam passes had different phase-matching temperature and compensated for miss conversions of other passes. In this work, continuous-wave 5 W green light (532 nm) with 66% conversion efficiency and wide temperature tolerance were obtained.

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