Abstract: A library terminal permits a user to execute a loan transaction without assistance. The library terminal (i) provides a visible scan line from a bar code reader indicating the correct positioning of the bar code on a circulating item, (ii) leads a user through a loan transaction, (iii) provides an explicit feedback to a user when an article has an improper position on the article receiving area, (iv) both checks out and checks in circulating items, (v) stores fonts in bit maps of screen displays instead of in a separate font memory, (vi) integrates a security marker reader, a printer, and a controller in the same housing, (vii) processes financial transactions related to the borrowing of circulating items, and/or (viii) displays actions for helping the user to correct errors in use of the terminal.

Abstract: A Schottky diode for millimeter and submillimeter wave applications is comprised of a multi-layered structure including active layers of gallium arsenide on a semi-insulating gallium arsenide substrate with first and second insulating layers of silicon dioxide on the active layers of gallium arsenide. An ohmic contact pad lays on the silicon dioxide layers. An anode is formed in a window which is in and through the silicon dioxide layers. An elongated contact finger extends from the pad to the anode and a trench, preferably a transverse channel or trench of predetermined width, is formed in the active layers of the diode structure under the contact finger. The channel extends through the active layers to or substantially to the interface of the semi-insulating gallium arsenide substrate and the adjacent gallium arsenide layer which constitutes a buffer layer.