Abstract: Apparatus is provided for investigating surface structures irrespective of the materials involved. A fine scanning tip is heated to a steady state temperature at a location remote from the structure to be investigated. Thereupon, the scanning tip is moved to a position proximate to, but spaced from the structure. At the proximate position, the temperature variation from the steady state temperature is detected. The scanning tip is scanned across the surface sturcture with the aforesaid temperature variation maintained constant. Piezo electric drivers move the scanning tip both transversely of, and parallel to, the surface structure. Feedback control assures the proper transverse positioning of the scanning tip and voltages thereby generated replicate the surface structure to be investigated.

Abstract: A fuel supply system is proposed for mixture-compressing internal combustion engines having externally supplied ignition. The fuel supply system includes an air intake tube delimited by an air filter, the air intake tube having a conical section downstream of which an arbitrarily actuatable throttle device is disposed. Associated with the conical section of the air intake tube is an air bypass line in which an air flow rate meter provided with a temperature-dependent resistor is disposed. The quantity aspirated by the engine is determined by this air flow rate meter. A fuel injection valve is disposed in such a manner that on one side it protrudes into the interior of the air filter and on the other side, with a slender mouthpiece, it protrudes approximately through the conical section. The fuel can be injected into the gap between the throttle device and the air intake tube wall by means of this mouthpiece. The fuel supply system according to the invention has a very low structural height.