refracting surface
71Skywave — is the propagation of electromagnetic waves bent (refracted) back to the Earth s surface by the ionosphere. As a result of skywave propagation, a broadcast signal from a distant AM broadcasting station at night, or from a shortwave radio station… …
72Astigmatism — A common form of visual impairment in which part of an image is blurred, due to an irregularity in the curvature of the front surface of the eye, the cornea. The curve of the cornea is shaped more like an American football or a rugby ball rather… …
73Axis — The axis is the second cervical vertebra (symbol: C2). It is called the axis because the uppermost cervical vertebra (called the atlas) rotates about the odontoid process of C2. The joint between the axis and atlas is a pivot type of joint. It… …
74USS Chicago (SSN-721) — is a Los Angeles class submarine, the fourth ship of the United States Navy to be named for the city of Chicago, Illinois. The contract to build her was awarded to Newport News Shipbuilding and Dry Dock Company in Newport News, Virginia on 13… …
75Timeline of astronomy — Timeline of astronomy2500 BCMany ancient sites are thought to have astronomical significance, such as the Ancient Egyptian pyramids, Harappan shell instruments, British megaliths, and buildings in China and Latin America.In Lothal, the ancient… …
763D rendering — is the 3D computer graphics process of automatically converting 3D wire frame models into 2D images with 3D photorealistic effects on a computer.Rendering methods Main Article: RenderingRendering is the final process of creating the actual 2D… …
77Microlens — A microlens is a small lens, generally with a diameter less than a millimetre (mm) and often as small as 10 micrometres (µm). The small sizes of the lenses means that a simple design can give good optical quality but sometimes unwanted effects… …
78Negative index metamaterials — A negative index metamaterial causes light to refract, or bend, differently than in more common positive refractive index materials. Negative index metamaterials or negative index materials (NIM) are artificial structures where the refractive… …
79Natural scientific research in Canada — This article outlines the history of natural scientific research in Canada, including mathematics, physics, astronomy, space science, geology, oceanography, chemistry, biology, medical research and psychology. The social sciences are not treated… …
80Microscopy — is the technical field of using microscopes to view samples and objects that cannot be seen with the unaided eye (objects that are not within the resolution range of the normal eye). There are three well known branches of microscopy, optical,… …
