Polarized infrared (IR) reflectance measurements were performed on polyoxymethylene (POM) prepared by the extrusion method, and an abnormally high reflectance of ∼90% was observed along the extruded direction in the 1000 cm−1–900 cm−1 region. High reflectivity was found in samples made by the conventional injection molding. However, the response of the extrusion sample was higher than that of the injection sample, which can be attributed to the Reststrahlen band. The relative permittivity calculated from the polarized reflection spectrum of the extruded direction shows a notably deep negative region in this high reflectance frequency. Using x rays, by differential scanning calorimetry, and by field emission scanning electron microscopy characterization, the difference in crystallinity and morphology from the extrusion and the injection molding plate was investigated, and the difference in IR optical response was discussed. The conventional IR band assignment of POM was also discussed.

Twenty-one thirsty rats were first trained to drink water from a tube 5 min per day. Then, six brief shocks were presented with an FI 45-sec schedule with (Group Sig) and without (Group No-Sig) a 5-sec warning signal. The shocks were then made alternately strong and weak. Suppression of licking behavior was a measure of emotion. Results were as follows: (1) Basal licking rate was consistently higher in Group Sig than in Group No-Sig. (2) There was clear evidence of temporal discrimination. (3) Rats' licking behavior was more suppressed before the stronger shock than before the weaker shock. Results as a whole indicate that rats in an aversive situation utilize an external cue, temporal cues, and shock intensities as predictors of aversive events. Mechanisms of cue utilization were discussed in conditioning terms.Past experiments have shown that chronic fear results when animals are placed in a situation in which an unsignaled aversive event, such as electric shock, is presented repeatedly. This same effect does not Occur if shocks are signaled by a specific cue. This chronic fear has been called a basal emotional level (BEL) (Imada, 1971). It has been indexed by the suppression of basal rate of barpressing for food in hungry animals (Hymovitz, 1973;Seligman, 1968), the suppression of basal rate of drinking in thirsty animals

No abstract

No abstract