The drum height was detected reliably, one of the main parameters for requirements of the shearer cutting memory program control was obtained. According to the principle of the drum lifting mechanism, two kinds of sensor detection conversion mathematical model based on the rocker angular displacement and the lifting cylinder linear displacement were established, the mathematical relation between the drum height and the sensor detection quantity and precision was derived, and the error of two kinds of detection was comparatively analyzed, therefore the theory basis to choose the sensor tape and precision to shearer cutting memory program control is provided.

The development on circular polarized LCD‐TV is summarized. A novel concept of circular polarized LCD‐TV is introduced. The effects of LCD‐TV's polarizing characteristics on visual fatigue during a long time watching are investigated. Results indicate that LCD‐TV with circular polarized transmission light causes less visual fatigue during long time watching compared with normal LCD‐TV.