A liquid crystal display array substrate. The communications system of the present invention includes a calling endpoint coupled to a called endpoint through a packet switched network. As the frequency of occurrence of an event is low in the case of a busy call, it becomes possible to accept the new call without degrading overall performance. A control processor calculates the location of the center and the notch of the wafer based on measurements by the sensor and generates an alignment signal for rotating the wafer gripping mechanism so that the wafer is oriented at a predetermined position on the end-effector while the robotic arm is moving to another station. , rows arranged in a triangular matrix, etc. The reactor that is the object of the invention is especially well suited for studying reactions of hydrogenation, hydrotreatment, and hydrocracking.