The present application provides a nozzle for a gas turbine engine. The retrograde well comprises a doped region with a vertically graded dopant concentration that is lowest at the substrate surface, and highest at the bottom of the well. The data value is read from or into the storage cells by coupling that data value to one of the bit lines in response to a row control signal on one of the row lines. A seal structure cooperates with the valve element to selectively seal the passage. The present invention is characterized in a small size; no need to install the device inside the instrument panel system; directly using an existing display device to generate a distant magnified virtual image; and easiness for users to install the device. This ability allows the operator to adjust flow for differing needs and may further decrease gas usage.