In an x-ray system and a method for tomosynthetic scanning of a subject, x-ray radiation is emitted from two x-ray sources that are panned along a line relative to the subject during a tomosynthetic scan. The electrical lead may also include either a resistive component for increasing the resistance of the electrical lead, or a diode for restricting the flow of electricity through the lead to a single direction. The engine control module generates a mean engine speed signal and a minimum engine speed signal. If a transmitter is determined to be present and available, maintaining the transmission wavelength of the tunable optical filter at transmission wavelength and assigning the ONT to the OLT as a subscriber at said identified transmission wavelength. The beverage contains of water, carbon dioxide, tea and sweetener. The single crystal has a periodical change in concentration of the n-type impurity in a thickness direction of the substrate.