One or more impurities may be incorporated within a metal-containing layer of a metal-containing gate electrode to modify the work function of the metal-containing gate electrode of a transistor can affect the threshold voltage of the transistor. The printer determines the average size of the ejected ink drops by comparing the number of ink drops ejected in a predetermined time with the quantity of ink delivered through the printers ink supply system during that time. The hingesupport structure is formed with a recessed region and a torsional hinge region. According to one embodiment, each cooling fin can be a graphene enhanced cooling fin. The dust-proof gate has a slit positioned communicating with the slot, wherein the slit extends along a direction parallel to a longitudinal length of the slot.