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Photofluorography
Photofluorography (sometimes called just fluorography) is photography of X-ray images from a fluorescence, fluorescent screen. It is commonly used in some countries for chest X-ray screening, e.g. to diagnose tuberculosis (see Abreugraphy for more information on such usage of this technique). Method of image formation in photofluorography X-ray beams from the tube get attenuation, attenuated by the patient producing a transmitted intensity (physics), radiation intensity corresponding to the part of the body traversed by the X-ray beam. Transmitted intensities now fall on the photocathode stimulating it to produce electrons in quantities external to the light intensities emitted by the input. This is caused by the formation of a light image of the transmitted radiation pattern. Electrons from the photocathode are accelerated and focused electronically out on the output phosphor which emits light as a result of electron bombardment. This shows a magnified image of what appears on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chest Photofluorography
Chest photofluorography, or abreugraphy (also called mass miniature radiography), is a photofluorography technique for mass Screening (medicine), screening for tuberculosis using a miniature (50 to 100 mm) photograph of the screen of an X-ray fluoroscopy of the thorax, first developed in 1936. History Abreugraphy receives its name from its inventor, Dr. Manuel Dias de Abreu, a Brazilian physician and pulmonology, pulmonologist. It has received several different names, according to the country where it was adopted: mass radiography, miniature chest radiograph (United Kingdom and United States), roentgenfluorography (Germany), radiophotography (France), schermografia (Italy), photoradioscopy (Spain) and photofluorography (Sweden). In many countries, miniature mass radiographs (MMR) was quickly adopted and extensively utilized in the 1950s. For example, in Brazil and in Japan, tuberculosis prevention laws went into effect, obligating ca. 60% of the population to undergo MMR scr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abreugraphy
Chest photofluorography, or abreugraphy (also called mass miniature radiography), is a photofluorography technique for mass screening for tuberculosis using a miniature (50 to 100 mm) photograph of the screen of an X-ray fluoroscopy of the thorax, first developed in 1936. History Abreugraphy receives its name from its inventor, Dr. Manuel Dias de Abreu, a Brazilian physician and pulmonologist. It has received several different names, according to the country where it was adopted: mass radiography, miniature chest radiograph (United Kingdom and United States), roentgenfluorography (Germany), radiophotography (France), schermografia (Italy), photoradioscopy (Spain) and photofluorography (Sweden). In many countries, miniature mass radiographs (MMR) was quickly adopted and extensively utilized in the 1950s. For example, in Brazil and in Japan, tuberculosis prevention laws went into effect, obligating ca. 60% of the population to undergo MMR screening. A model of a mass radiograp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Bombardment
Electron ionization (EI, formerly known as electron impact ionization and electron bombardment ionization) is an ionization method in which energetic electrons interact with solid or gas phase atoms or molecules to produce ions. EI was one of the first ionization techniques developed for mass spectrometry. However, this method is still a popular ionization technique. This technique is considered a hard (high fragmentation) ionization method, since it uses highly energetic electrons to produce ions. This leads to extensive fragmentation, which can be helpful for structure determination of unknown compounds. EI is the most useful for organic compounds which have a molecular weight below 600. Also, several other thermally stable and volatile compounds in solid, liquid and gas states can be detected with the use of this technique when coupled with various separation methods. History Electron ionization was first described in 1918 by Canadian-American Physicist Arthur J. Dempster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinescope
Kinescope , shortened to kine , also known as telerecording in Britain, is a recording of a television program on motion picture film, directly through a lens focused on the screen of a video monitor. The process was pioneered during the 1940s for the preservation, re-broadcasting and sale of television programmes before the introduction of quadruplex videotape, which from 1956 eventually superseded the use of kinescopes for all of these purposes. Kinescopes were the only practical way to preserve live television broadcasts prior to videotape. Typically, the term Kinescope can refer to the process itself, the equipment used for the procedure (a movie camera mounted in front of a video monitor, and synchronized to the monitor's scanning rate), or a film made using the process. The term originally referred to the cathode ray tube used in television receivers, as named by inventor Vladimir K. Zworykin in 1929. Hence, the recordings were known in full as kinescope films or kines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Videotape Recorder
A video tape recorder (VTR) is a tape recorder designed to record and playback video and audio signal, audio material from magnetic tape. The early VTRs were reel-to-reel, open-reel devices that record on individual reels of 2-inch-wide (5.08 cm) tape. They were used in television studios, serving as a replacement for motion picture film stock and making recording for television applications cheaper and quicker. Beginning in 1963, videotape machines made instant replay during televised sporting events possible. Improved formats, in which the tape was contained inside a videocassette, were introduced around 1969; the machines which play them are called videocassette recorders. An agreement by Japanese manufacturers on a common standard recording format, which allowed cassettes recorded on one manufacturer's machine to play on another's, made a consumer market possible; and the first consumer videocassette recorder, which used the U-matic format, was introduced by Sony in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photodetector
Photodetectors, also called photosensors, are sensors of light or other electromagnetic radiation. There is a wide variety of photodetectors which may be classified by mechanism of detection, such as Photoelectric effect, photoelectric or photochemical effects, or by various performance metrics, such as spectral response. Semiconductor-based photodetectors typically photo detector have a p–n junction that converts light photons into current. The absorbed photons make electron–hole pairs in the depletion region. Photodiodes and photo transistors are a few examples of photo detectors. Solar cells convert some of the light energy absorbed into electrical energy. Types Photodetectors may be classified by their mechanism for detection: * Photoemission or photoelectric effect: Photons cause electrons to transition from the conduction band of a material to free electrons in a vacuum or gas. * Thermal: Photons cause electrons to transition to mid-gap states then decay back to lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TV Camera
A professional video camera (often called a television camera even though its use has spread beyond television) is a high-end device for creating electronic moving images (as opposed to a movie camera, that earlier recorded the images on film). Originally developed for use in television studios or with outside broadcast trucks, they are now also used for music videos, direct-to-video movies (see digital movie camera), corporate and educational videos, wedding videos, among other uses. Since the 2000s, most professional video cameras are digital (instead of analog) professional video cameras. The distinction between professional video cameras and movie cameras became much smaller as HD digital video cameras with sensors the same size as 35mm movie cameras - plus dynamic range (exposure latitude) and color rendition approaching film quality - were introduced in the late 2010s. Nowadays, HDTV cameras designed for broadcast television, news, sports, events and other works such as rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power. In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower opti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Film
Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin photographic emulsion, emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the crystals determine the sensitivity, contrast, and image resolution, resolution of the film. The emulsion will gradually darken if left exposed to light, but the process is too slow and incomplete to be of any practical use. Instead, a very short exposure (photography), exposure to the image formed by a camera lens is used to produce only a very slight chemical change, proportional to the amount of light absorbed by each crystal. This creates an invisible latent image in the emulsion, which can be chemically photographic processing, developed into a visible photograph. In addition to visible light, all films are sensitive to ultraviolet light, X-rays, gamma rays, and particle radiation, high-energy particles. Unmodified silver halide crys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camera Lens
A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically. There is no major difference in principle between a lens used for a still camera, a video camera, a telescope, a microscope, or other apparatus, but the details of design and construction are different. A lens might be permanently fixed to a camera, or it might be interchangeable with lenses of different focal lengths, apertures, and other properties. While in principle a simple convex lens will suffice, in practice a compound lens made up of a number of optical lens elements is required to correct (as much as possible) the many optical aberrations that arise. Some aberrations will be present in any lens system. It is the job of the lens designer to balance these and produce a desi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photography
Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed in many fields of science, manufacturing (e.g., photolithography), and business, as well as its more direct uses for art, film and video production, recreational purposes, hobby, and mass communication. Typically, a lens is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure. With an electronic image sensor, this produces an electrical charge at each pixel, which is electronically processed and stored in a digital image file for subsequent display or processing. The result with photographic emulsion is an invisible latent image, which is later chemically "developed" into a visible image, either negative or positive, depending on the purp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz ( to ) and energies in the range 145 eV to 124 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it on November 8, 1895. He named it ''X-radiation'' to signify an unknown type of radiation.Novelline, Robert (1997). ''Squire's Fundamentals of Radiology''. Harvard University Press. 5th edition. . Spellings of ''X-ray(s)'' in English include the variants ''x-ray(s)'', ''xray(s)'', and ''X ray(s)''. The most familiar use of X-rays is checking for fractures (broken bones), but X-rays are also used in other ways. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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