an implement consisting of a broad blade or scoop attached to a long handle, used for taking up, removing, or throwing loose matter, as earth, snow, or coal. 2. any fairly large contrivance or machine with a broad blade or scoop for taking up or removing loose matter: a steam shovel. 3. a shovelful.
Advanced Cone Beam CT Technology. CBCT scanners, on the other hand, are based on volumetric tomography, using a 2D extended digital array providing an area detector. This is combined with a 3D x-ray beam (Fig. 1b). The cone-beam technique involves a single 360Â° scan in which the x-ray source and a reciprocating area detector synchronously move around the patientâs head, which is stabilized with a head holder. At certain degree intervals, single projection images, known as âbasisâ images, are acquired.
CONVEX or POSITIVE lenses will CONVERGE or FOCUS light and can form an IMAGE. CONCAVE or NEGATIVE lenses will DIVERGE (spread out) light rays. You can have mixed lens shapes too: See a demonstration (opens a new window) of what happens to the light path when you combine several convex or concave lenses. Perfectly straight, until something bends it. The straight paths of light are called LIGHT RAYS.