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Defect concentration in polycrystalline silicon (poly-Si) films formed by thermal plasma jet (TPJ) annealing and excimer laser annealing (ELA) has been investigated on basis of the electrical property and spin density (Ns). Phosphorus-doped Si films with an average concentration of 4.3 ×1017 cm-3 and crystallized by TPJ annealing showed electrical conductivity (σ) values of 2.0 ×10-3–7.8 ×10-2 S/cm, whereas ELA Si films show much lower σ values of (1.6–4.5) ×10-6 S/cm regardless of irradiated laser energy density. Ns values in TPJ annealed Si films were (2.3–4.5) ×1017 cm-3, which are roughly one order of magnitude lower than those of ELA films. These results indicate that dangling bonds in crystallized films are the predominant traps and they strongly govern the electrical property. TPJ crystallization offers the possibility of fabricating poly-Si films with a low defect concentration presumably owing to the much lower cooling rate (~105 K/s) during crystalline growth than that of ELA (~1010 K/s). By treating TPJ annealed films with hydrogen plasma for 10 min at 250 °C, a defect density as low as 5.0 ×1016 cm-3 is achieved.

We have observed the time course features of cerebral response while a subject is performing the visual tracking task or visual tracking plus finger tapping task using Optiocal Topography (OT). The distribution maps of both oxygenated and deoxygenated hemoglobins are demonstrated in contrast with the time course diagram. The response of the cerebrum differs, depending on whether the optical stimulation is static or dynamic, even when the overall nature of the pattern and intensity of the stimulation is the same. The cerebral response to a dynamic optical stimulation is very rapid and clear, and greater in magnitude than that to static optical stimulation, but it is suppressed when an auxiliary finger tapping task is also performed. From these results, it was confirmed that OT is sensitive to both static and dynamic optical stimulations.

A method of measuring the electrical conductivity of solids (such as biochemical materials) is discussed. The resistance R (Ω) obtained by using a pair of electrodes with the radius a (cm) and the length l (cm) separated at the distance D (cm) gives the conductivity σ (Ω·cm)-1, σ=ln (D/a)/πR l. The error caused by the difference in the size of material and the electrode separation or the electrode length is investigated. The resistivity of a raw radish is investigated as a function of the frequency as an example of this method. The order of the resistivity is 1 kΩ·cm at low frequency (∼100 Hz) and is 100 Ω·cm at high frequency (∼1 MHz) where the current flow is not impeded by cell membrane.