TY - JOUR AU - Hauptmann, Peter AU - Lucklum, Ralf AU - PĆ¼ttmer, Alf AU - Henning, Bernd ID - 13810 IS - 1-3 JF - Sensors and Actuators A: Physical TI - Ultrasonic sensors for process monitoring and chemical analysis state of the art and trends VL - 67 ER -