Abstract: An organic thin film transistor with circular semiconducting elements applied to the substrate in a plurality of hexagonal patterns, a method of producing the same, and a shadow mask used in the method that allows for formation of the organic thin film transistor without need for precise alignment of the shadow mask on the substrate. The substrate has a plurality of thin film transistors, each having a drain electrode, a source electrode, a gate electrode, and a channel formed of semiconducting elements that, due to relative dimensions and alignments of the semiconducting elements, may connect both the drain electrode and the source electrode of one transistor but not two electrodes of adjacent transistors. The shadow mask includes openings in the hexagonal pattern, and the pattern is rotated at an angle of 15° relative to longitudinal axes of the drain and source electrodes to form channels.

Abstract: Provided are a heat exchanger assembly and a method of cooling the outlet stream of a fuel cell using the heat exchanger assembly, which increase the efficiency of heat exchange in fuel cell systems. The heat exchanging assembly for fuel cell systems comprising a heat exchanger and a ventilation unit for cooling the heat exchanger, wherein the heat exchanger comprises: an inlet manifold with an inlet opening, an outlet manifold with an outlet opening, and a plurality of heat exchanging elements disposed between the inlet opening of the inlet manifold and the outlet opening of the outlet manifold and connecting the inlet manifold and the outlet manifold, wherein cooling air generated by the ventilation unit flows in the opposite direction to the flow of a medium within the heat exchanging elements.

Abstract: An organic thin film transistor with circular semiconducting elements applied to the substrate in a plurality of hexagonal patterns, a method of producing the same, and a shadow mask used in the method that allows for formation of the organic thin film transistor without need for precise alignment of the shadow mask on the substrate. The substrate has a plurality of thin film transistors, each having a drain electrode, a source electrode, a gate electrode, and a channel formed of semiconducting elements that, due to relative dimensions and alignments of the semiconducting elements, may connect both the drain electrode and the source electrode of one transistor but not two electrodes of adjacent transistors. The shadow mask includes openings in the hexagonal pattern, and the pattern is rotated at an angle of 15° relative to longitudinal axes of the drain and source electrodes to form channels.