The responses of single cells to luminance, color and computer-generated spots, bars, kinematograms, and motion-in-depth stimuli were studied in the nucleus rotundus of pigeons. Systematic electrode penetrations revealed that there are several functionally distinct subdivisions within rotundus where six classes of visual-selective cells cluster. Cells in the dorsal-posterior zone of the nucleus respond selectively to motion in depth (i.e. an expanding or contracting figure in the visual field). Most cells recorded from the dorsal-anterior region responded selectively to the color of the stimulus. The firing rate of the cells in the anterior-central zone, however, is dramatically modulated by changing the level of illumination over the whole visual field. Cells in the ventral subdivision strongly respond to moving occlusion edges and very small moving objects, with either excitatory or inhibitory responses. These results indicate that visual information processing of color, ambient illumination, and motion in depth are segregated into different subdivisions at the level of nucleus rotundus in the avian brain.
The main bearing of the shield machine has a huge structure and severe service conditions, which are prone to wear and fatigue damage. To improve the anti-wear and anti-fatigue ability of the raceway surface of the shield main bearing, laser transformation hardening under different parameters of the shield main bearing raceway material 42CrMo steel was researched. The effects of laser power and scanning speed on the phase transformation of 42CrMo steel and the depth of the hardened layer were studied. The numerical model was verified using the theoretical and experimental results. Orthogonal tables of laser processing parameters are established. The results show that the depth of the hardened raceway layer increases with increased laser power and decreased laser scanning speed. According to the results of orthogonal primary and secondary analyses and fuzzy comprehensive evaluation, the depth of the hardened layer of the raceway can reach 1.08 mm, and the hardened layer is relatively uniform (laser power, 2250 W; scanning speed, 20 mm/s; spot length, 5 mm). The research in this paper provides a theoretical basis and technological innovation for the processing methods and engineering applications of high-reliability and long-life shield main bearings, which is of great engineering significance.
This study puts forward a calculation of the transitions of 1s2s22p 1P1-1s22s2 1S0 and 1s2s22p 3P1-1s22s2 1S0 for Be-like ions (Z=6-30) using the multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction methods. The computational results include transition wavelengths, transition probabilities, line strengths, and weighted oscillator strengths. The calculations also consider the contributions of the Breit interaction and quantum electrodynamics corrections (QED) to these levels. The results show that the contribution of the Breit interaction, self-energy, and vacuum polarization increase rapidly with increasing nuclear charge for certain configurations. The present calculated values are in good agreement with previous theoretical and experimental results, with errors better than 0.3%. AV / AL comparisons demonstrate the reliability of the data.
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