Shurugwi, town, central Zimbabwe. Shurugwi was established in 1899 by the British South Africa Company and Willoughby’s Consolidated Company. Its name was derived from a nearby bare oval granite hill that resembled the shape of a pigpen (selukwe) of the local Venda people. The town is the terminus

Precambrian: Age and occurrence of greenstone-granite belts: …over three successive periods: the Selukwe belt about 3.8 to 3.75 billion years ago, the Belingwean belts about 2.9 billion years ago, and the Bulawayan-Shamvaian belts about 2.7 to 2.6 billion years ago. The Barberton belt in the Kaapvaal craton and the Warrawoona belt in the Pilbara block are 3.5…

Status of the World’s Tropical Forests: As recently as the 19th century tropical forests covered approximately 20 percent of the dry land area on Earth. By the end of the 20th century this figure had dropped to less than 7 percent. The factors contributing to deforestation are numerous, complex, and often…

rat opossum, (family Caenolestidae), any of six species of South American marsupials in the order Paucituberculata. Rat opossums include the common shrew opossums (genus Caenolestes) with four species, the Incan caenolestid (Lestoros inca), and the Chilean shrew opossum (Rhyncholestes raphanurus).

José Maria Ferreira de Castro: Two novels—Emigrantes (1928; “Emigrants”) and A selva (1930; “The Jungle,” translated into more than a dozen languages)—launched Ferreira de Castro’s literary career and offered an almost photographic portrayal of an exotic region and its human tensions and high drama.

weaving: …avoids raveling; these are called selvages. They run lengthwise, parallel to the warp yarns. The three basic weaves are plain, twill, and satin. Fancy weaves—such as pile, Jacquard, dobby, and leno—require more complicated looms or special loom attachments for their construction.

cable: Selvage cables composed of parallel wires are ideally suited for the main cables of a suspension bridge. Marine ropes are used for rigging, mooring, and towing.

Madeira Islands: …groups, the Desertas and the Selvagens. The islands are the summits of mountains that have their bases on an abyssal ocean floor. Administratively, they form the autonomous region of Madeira. The regional capital, Funchal, is located on Madeira Island.

Miguel de Cervantes: Publication of Don Quixote: …of his attendance at the Academia Selvaje, a kind of writers’ salon, in 1612.

Samuel Selvon was a Caribbean novelist and short-story writer of East Indian descent, known for his vivid evocation of the life of East Indians living in the West Indies and elsewhere. He came to public attention during the 1950s with a number of other Caribbean writers, including V.S. Naipaul.

Samuel Selvon was a Caribbean novelist and short-story writer of East Indian descent, known for his vivid evocation of the life of East Indians living in the West Indies and elsewhere. He came to public attention during the 1950s with a number of other Caribbean writers, including V.S. Naipaul.

Radiohead: April 15, 1968, Oxford), drummer Phil Selway (b. May 23, 1967, Hemingford Grey, Huntingdon, Cambridgeshire), and guitarist-keyboardist Jonny Greenwood (b. November 5, 1971, Oxford).

Selwyn Mountains, mountain range in Yukon and Northwest Territories, northwestern Canada. Part of the Rockies, they trend northwest-southeast and rise to 9,750 feet (2,972 metres) in Keele

George Augustus Selwyn was the first Anglican bishop of New Zealand. Selwyn was educated at Eton and St. John’s College, Cambridge. In 1833 he was ordained a deacon and became a curate at Windsor. He was made bishop of New Zealand in 1841. He learned to preach in Maori and to sail his own vessel

Selwyn Lloyd was a British Conservative politician who was foreign secretary during Britain’s diplomatic humiliation in the Suez crisis of 1956 and later chancellor of the exchequer under Prime Minister Harold Macmillan. Lloyd studied law at Cambridge and was called to the bar in 1930. After World

Hans Selye was an endocrinologist known for his studies of the effects of stress on the human body. Selye was educated at the German University of Prague (M.D., 1929; Ph.D., 1931) and at the universities of Paris and Rome. In 1931 he came to the United States to work as a research fellow at Johns

Hans Selye was an endocrinologist known for his studies of the effects of stress on the human body. Selye was educated at the German University of Prague (M.D., 1929; Ph.D., 1931) and at the universities of Paris and Rome. In 1931 he came to the United States to work as a research fellow at Johns

thought: The process of thought: The German psychologist Otto Selz countered that in many situations this kind of theory would imply the occurrence of errors as often as correct answers to questions and thus was untenable. Selz contended that response selection depends rather on a process of “complex completion” that is set in…

David O. Selznick was an American motion-picture producer who earned a reputation for commercially successful films of high artistic quality before and after World War II. Selznick received his early training in motion pictures from his father, Lewis J. Selznick, a producer of silent films in New

organizational analysis: Theoretical developments: …American sociologist and legal scholar Philip Selznick, like Michels, emphasized the nonrational aspects of organizations. Using the Tennessee Valley Authority (TVA) as an example, he argued that one of the most important features of organizations is the tendency for structures and processes to become “infused with value beyond the technical…

standard error of measurement (SEM), the standard deviation of error of measurement in a test or experiment. It is closely associated with the error variance, which indicates the amount of variability in a test administered to a group that is caused by measurement error. The standard error of

scanning electron microscope (SEM), type of electron microscope, designed for directly studying the surfaces of solid objects, that utilizes a beam of focused electrons of relatively low energy as an electron probe that is scanned in a regular manner over the specimen. The electron source and

Nagaland: Cultural life: …and hereditary chieftainships of the Semas and Changs to the democratic structures of the Angamis, Aos, Lothas, and Rengmas. A prominent village institution is the morung (a communal house or dormitory for young unmarried men), where skulls and other trophies of war formerly were hung. The pillars are still carved…

cnidarian: Annotated classification: Order Semaeostomeae Most common and best known jellyfishes. Full alternation of polyp and medusa stages. Bell domed or flattened, with the margin scalloped into 8 or more sections. Edges of single mouth drawn out into 4 long arms. Most species in warm, coastal waters, a few…

Adam Ważyk: Ważyk’s earliest volumes of poetry, Semafory (1924; “Semaphores”) and Oczy i usta (1926; “Eyes and Lips”), were written between the ages of 17 and 20 and reflect the instability of life in Poland after World War I and the pervasive sense of loss left in its wake. Ważyk was closely…

semaglutide, drug used in the treatment of type 2 diabetes and to aid weight loss in persons who are severely overweight. Semaglutide was initially approved by the U.S. Food and Drug Administration (FDA) in 2017 to help control blood glucose levels in persons with type 2 diabetes; the drug was

Austroasiatic languages: Morphology: …of noun phrases (possessives in Semai, demonstratives in Mnong), but these do not constitute word suffixes. (2) Infixes and prefixes are common, so that only the final vowel and consonant of a word root remain untouched. It is rare to find more than one or two affixes (i.e., prefixes or…

Guillaume de Salluste, seigneur du Bartas: …Coudons) was the author of La Semaine (1578), an influential poem about the creation of the world.

Banda: Age grades and initiations called semali assured intergroup unity in time of war. Marriage traditionally required bridewealth, often in iron implements. Polygyny, although still practiced, has declined with the rise of a money-based economy.

Modernismo: …gained wide recognition with its Semana de Arte Moderna (“Week of Modern Art”), an event held in São Paulo in 1922, provoking controversy with lectures on the aims of Modernism and readings from works by such Modernist poets as Mário de Andrade (q.v.).

Semang, people who live mostly in peninsular Malaysia and speak an Austro-Asiatic language. In the early 21st century their population was estimated to be approximately 2,000. They are traditional nomadic hunters, using blowguns to hunt small game, and gatherers of wild roots and fruits. Most

Jahaic languages, a subbranch of the Aslian branch of the Mon-Khmer family, itself a part of the Austroasiatic stock. The group includes Bateg, Che’ Wong, Jahai, Kensiw, Kenta’, and Menriq. The language group is a small one, with total speakers estimated at some 5,000. They are located mainly in

Malaysia: Malaysia from independence to c. 2000: Mahathir’s opponents countered by forming Semangat ’46 (Spirit of ’46), which claimed to embody the ideals of the original UMNO (established in 1946) and attempted to unite the disparate opposition groups against the ruling BN coalition headed by UMNO.

percussion instrument: Idiophones: …percussion beams, such as the semanterion; percussion disks and plaques, single and in sets; xylophones, lithophones (sonorous stones), and metallophones (sets of tuned metal bars); percussion tubes, such as stamping tubes, slit drums, and tubular chimes; and percussion vessels varying from struck gourds and pots to gongs, kettle gongs, steel…

philosophy of biology: The structure of evolutionary theory: Supporters of the “semantic” conception argue that scientific theories are rarely, if ever, hypothetico-deductive throughout, and that in any case the universal laws presupposed by the hypothetico-deductive model are usually lacking. Especially in biology, any attempt to formulate generalities with anything like the necessity required of natural laws…

cyberwar: Attacks in cyberspace: Finally, semantic cyberattacks, also known as social engineering, manipulate human users’ perceptions and interpretations of computer-generated data in order to obtain valuable information (such as passwords, financial details, and classified government information) from the users through fraudulent means. Social-engineering techniques include phishing—in which attackers send seemingly…

Hilary Putnam: Realism and meaning: This conception, known as semantic externalism, can therefore serve as a basis for an objective account of truth and knowledge. Consequently, it can also support realism—and was indeed employed by Putnam (and many others after him) to that end.

memory: Long-term memory: …an association, known as “semantic” memories. The latter category includes definitions and many kinds of factual knowledge, such as knowledge of the name of the current pope, which one might not recall having learned at any particular time or place.

information processing: Semantic content analysis: In a so-called semantic network, conceptual entities such as objects, actions, or events are represented as a graph of linked nodes (Figure 4). “Frames” represent, in a similar graph network, physical or abstract attributes of objects and in a sense define the objects. In “scripts,” events and actions…

formal logic: Semantic tableaux: Since the 1980s another technique for determining the validity of arguments in either PC or LPC has gained some popularity, owing both to its ease of learning and to its straightforward implementation by computer programs. Originally suggested by the Dutch logician Evert W.…

Semantic Web, extension of the World Wide Web (WWW) in which data are given meaning (semantics) to enable computers to look up and “reason” in response to user searches. One of the strongest proponents of the Semantic Web is Sir Tim Berners-Lee, the British inventor of the WWW and the director of

semantics, the philosophical and scientific study of meaning in natural and artificial languages. The term is one of a group of English words formed from the various derivatives of the Greek verb sēmainō (“to mean” or “to signify”). The noun semantics and the adjective semantic are derived from

semaphore, method of visual signaling, usually by means of flags or lights. Before the invention of the telegraph, semaphore signaling from high towers was used to transmit messages between distant points. One such system was developed by Claude Chappe in France in 1794, employing a set of arms

Southeast Asian arts: Characters: …the chief Javanese clown figure, Semar, is derived from an ancient Javanese god who was deposed from his supreme position by the introduction into the drama of the later Hindu gods. In the midst of mythological plays, the clowns comment irreverently on political or social issues of the day, seemingly…

Western Sahara: History: …1902 constructed the town of Semara at an inland oasis. Cape Juby (Ṭarfāyah) was occupied for Spain by Col. Francisco Bens in 1916, Güera was occupied in 1920, and Semara and the rest of the interior were occupied in 1934.

Semarang, kota (city), port, and capital of Central Java (Jawa Tengah) propinsi (or provinsi; province), Indonesia. It lies on the northern coast of the island of Java. The city, divided into old and new sections, is just inland from the port and on the banks of the Baru River and the West Banjir

semantics, the philosophical and scientific study of meaning in natural and artificial languages. The term is one of a group of English words formed from the various derivatives of the Greek verb sēmainō (“to mean” or “to signify”). The noun semantics and the adjective semantic are derived from

Robert Noyce: Statesman: …an important role in establishing Sematech, a joint industry-government consortium formed with sometimes conflicting goals—research to keep the American semiconductor industry at the forefront and efforts to maintain a domestic semiconductor manufacturing capacity. Noyce became Sematech Inc.’s first president in 1988.

mammal: Skin and hair: … or hamadryas baboon, warning (sematic), as seen in the bold pattern of skunks, or concealing (cryptic), perhaps the most common adaptation of pelage colour.

Ōsaka-Kōbe metropolitan area: Settlement patterns: …of Ōsaka railway station; the Semba Centre Building, which although only four floors in height extends about three-fifths of a mile along Chūō Ōdōri and is constructed under an elevated expressway and over a subway; and the convention centre built on the man-made Port Island in Kōbe Harbour.

Thousand Cranes, novel by Kawabata Yasunari, published serially in several newspapers beginning in 1949 and published as Sembazuru with the novel Yama no Oto (The Sound of the Mountain) in 1952. One of Kawabata’s finest works, Thousand Cranes was written in part as a sequel to Yukiguni (1948; Snow

Ousmane Sembène was a Senegalese writer and film director known for his historical and political themes. (Read Martin Scorsese’s Britannica essay on film preservation.) Sembène spent his early years as a fisherman on the Casamance coast. He studied at the School of Ceramics at Marsassoum and then

Marcella Sembrich was a Polish coloratura known for both her operatic and her concert work. Marcelina Kochańska learned to play the violin and piano from her father and performed on both instruments in recital when she was 12 years old. She also studied piano and voice with Wilhelm Stengel, whom

Kru languages: …groups is another Kru language, Seme (Sεmε), which is spoken in Burkina Faso hundreds of miles away from any other Kru language. Its location is of particular interest as it lends support to the hypothesis that in earlier times the Kru population had lived farther north; but, under pressure from…

Ignazio Silone: …seme sotto la neve (1940; The Seed Beneath the Snow, 1942), portray socialist heroes who try to help the peasants by sharing their sufferings in a Christian spirit. Pane e vino was dramatized in 1944 as Ed egli si nascose (London, And He Did Hide Himself, New York, And He…

Sapindales: Distribution and abundance: …genera of comparable size, but Semecarpus (occurring from Indo-Malaysia to Micronesia) has about 60 species, Mangifera (occurring in Southeast Asia and Indo-Malaysia to Solomon Islands) has about 40 species, and Schinus (occurring from Mexico to Argentina) has about 30 species.

Sapindales: Anacardiaceae: Semecarpus anacardium (dhobi nut) has young fruits with a black resin that is insoluble in water and is used as a marking ink in Southeast Asia.

nightjar: The pennant-winged nightjar (Semeiophorus vexillarius) of Africa gets its name from its boldly patterned black and white wing, which has greatly lengthened innermost primary flight feathers (50 to 70 cm [20 to 28 inches]).

Semelaic languages, (from Malay orang asli, “aborigines”), subbranch of the Aslian branch of the Mon-Khmer language family, which is itself a part of the Austroasiatic stock. The subbranch consists of three languages spoken in southern and central Malaysia: Betise’ (previously known as Mah Meri, or

Semele, in Greek mythology, a daughter of Cadmus and Harmonia, at Thebes, and mother of Dionysus (Bacchus) by Zeus. Semele’s liaison with Zeus enraged Zeus’s wife, Hera, who, disguised as an old nurse, coaxed Semele into asking Zeus to visit her in the same splendour in which he would appear before

aging: Reproduction and aging: The distinction between semelparous and iteroparous modes of reproduction is important for an understanding of biological aging. Semelparous organisms reproduce by a single reproductive act. Annual and biennial plants are semelparous, as are many insects and a few vertebrates, notably salmon and eels. Iteroparous organisms, on the other…

semen, fluid that is emitted from the male reproductive tract and that contains sperm cells, which are capable of fertilizing the female’s eggs. Semen also contains liquids that combine to form seminal plasma, which helps keep the sperm cells viable. In the sexually mature human male, sperm cells

semen analysis, laboratory examination of a sample of seminal fluid, usually consisting of the determination of semen volume, alkalinity or acidity (pH), sperm number (or sperm count), and the motility, shape, and viability of sperm. An examination of seminal fluid is usually undertaken to check

Peninsular Malaysia, region of the 13-state federation of Malaysia. It occupies the southern half of the Malay Peninsula and is separated from East Malaysia (on the island of Borneo) by the South China Sea. Formerly the Federation of Malaya (1948–63), it contains the bulk of Malaysia’s population

Nikolay Nikolayevich Semyonov was a Soviet physical chemist who shared the 1956 Nobel Prize for Chemistry with Sir Cyril Hinshelwood for research in chemical kinetics. He was the second Soviet citizen (after the émigré writer Ivan Bunin) to receive a Nobel Prize. Semyonov was educated in St.

Gregg L. Semenza is an American physician and scientist known for his investigations of how cells use and regulate oxygen and for his discovery of hypoxia-inducible factor (HIF), a molecule that is activated by reduced oxygen availability in cells and that plays a critical role in enabling cells to

Mount Semeru, active stratovolcano in eastern Java, Indonesia. Its summit reaches 12,060 feet (3,676 meters) above sea level, making it both the highest volcano and the highest mountain on the island. Semeru is one of the most active volcanoes in the world, having erupted nearly continuously,

Mount Semeru, active stratovolcano in eastern Java, Indonesia. Its summit reaches 12,060 feet (3,676 meters) above sea level, making it both the highest volcano and the highest mountain on the island. Semeru is one of the most active volcanoes in the world, having erupted nearly continuously,

AlliedSignal: …Company (founded 1917), producing dyes; Semet-Solvay Company (founded 1894), manufacturing coke and its by-products; and Solvay Process Company (founded 1881), producing alkalies and nitrogen materials. In the 1940s these companies were transformed into “divisions” of Allied Chemical. There were further reorganizations and acquisitions of companies and plants during the 1950s,…

Semey, city, eastern Kazakhstan. It is a port on the Irtysh (Ertis) River where the latter emerges into the West Siberian Plain. It was founded as a Russian fort in 1718, 11 miles (18 km) downstream from the present site, near the ruins of a Buddhist monastery consisting of seven buildings, from

Sergey Timofeyevich Aksakov: …become classics: Semeynaya khronika (1856; The Family Chronicle), Vospominaniya (1856; “Reminiscences”; Eng. trans. A Russian Schoolboy), and Detskie gody Bagrova-vnuka (1858; Childhood Years of Grandson Bagrov). Aksakov unfolds his chronicles objectively in an unaffected style with simple language. Their interest lies in the illusion of reality and intimacy created by…

truck: Types and definitions: …weight and load of a semitrailer, which is a truck trailer equipped with one or more axles and constructed so that the end and a substantial part of its own weight and that of its load rests upon a truck tractor. In contrast, a full trailer is constructed so that…

semi-Arianism, a 4th-century Trinitarian heresy in the Christian church. Though it modified the extreme position of Arianism, it still fell short of the church’s orthodox teaching that Father, Son, and Holy Spirit are of the same substance. Arius held that the Father and the Son are of distinct

warning system: Air defense systems: Examples include the semiautomatic ground environment (SAGE), augmented by a mobile backup intercept control system called BUIC in the United States, NATO air defense ground environment (NADGE) in Europe, a similar system in Japan, and various land-mobile, airborne, and ship command and control systems. Little information concerning the…

liquid: Activity coefficients and excess functions: …zero, but two types of semi-ideal solutions can be designated: in the first, SE is zero but HE is not; this is called a regular solution. In the second, HE is zero but SE is not; this is called an athermal solution. An ideal solution is both regular and athermal.

film noir: Defining the genre: …sometimes designated as “semi-noir,” or film gris (“gray film”), to indicate their hybrid status.

semi-Pelagianism, in 17th-century theological terminology, the doctrine of an anti-Augustinian movement that flourished from about 429 to about 529 in southern France. The surviving evidences of the original movement are limited, but it is clear that the fathers of semi-Pelagianism were monks who

Will Ferrell: Elf, Anchorman, and Talladega Nights: …Blades of Glory (2007) and Semi-Pro (2008).

Pakistan: Housing of Pakistan: …bamboo, reeds, or thatch); and semi-pukka houses, which are a mix between the two. Housing stocks comprise an equal number of semi-pukka and katchi houses (about two-fifths each), and remaining houses (roughly one-fifth of the total) are the better-variety pukka houses. Urban areas are dominated by ramshackle neighborhoods known locally…

Michael Ritchie: Films: Semi-Tough (1977) followed, a genial adaptation of Dan Jenkins’s humorous novel about the world of professional football. Burt Reynolds and Kris Kristofferson starred as teammates who both love the owner’s daughter (Jill Clayburgh). It was only a modest hit, with much criticism directed at the…

rocket and missile system: Semiactive: Semiactive guidance involved illuminating or designating the target with energy emitted from a source other than the missile; a seeker in the projectile that was sensitive to the reflected energy then homed onto the target. Like active guidance, semiactive guidance was commonly used for…

alluvial fan: …more prominent in arid and semiarid regions, however, and generally are regarded as characteristic desert landforms. This is particularly true in the basin-and-range type of areas of parts of Iran, Afghanistan, Pakistan, the western United States, Chile and Peru, Sinai and western Arabia, and Central Asia, where the basic landscape…

mineral processing: Grinding: …development is the autogenous or semiautogenous mill. Autogenous mills operate without grinding bodies; instead, the coarser part of the ore simply grinds itself and the smaller fractions. To semiautogenous mills (which have become widespread), 5 to 10 percent grinding bodies (usually metal spheres) are added.

warning system: Air defense systems: Examples include the semiautomatic ground environment (SAGE), augmented by a mobile backup intercept control system called BUIC in the United States, NATO air defense ground environment (NADGE) in Europe, a similar system in Japan, and various land-mobile, airborne, and ship command and control systems. Little information concerning the…

semiautomatic pistol, handgun that utilizes either recoil or blowback to discharge the empty cartridge, reload, and cock the piece after each shot. The semiautomatic pistol dates from the very late 19th century, when developments in ammunition made possible cartridges and bullets that would feed or

automatic rifle: …should not be confused with semiautomatic rifles, as the latter fire only one shot at each pull of the trigger. An automatic rifle fires repeatedly as long as the trigger is held down, until the magazine is exhausted. That fully automatic firing is achieved by weapons such as the machine…

shotgun: In semiautomatic shotguns, firing a shot automatically positions the next round.

soap and detergent: Cold and semiboiled methods: In the semiboiled method, the fat is placed in the kettle and alkali solution is added while the mixture is stirred and heated but not boiled. The mass saponifies in the kettle and is poured from there into frames, where it solidifies. Because these methods are technically…

desmid: …cell is divided symmetrically into semicells connected at a central isthmus. The three-layered cell wall is impregnated with openings or pores and pectin spicules; irregular desmid movement is caused by the flow of a gelatinous substance through these pores. Conjugation (temporary union for the exchange of nuclear material) is the…

papermaking: Semichemical pulp: For semichemical pulping, wood preparation and chipping are essentially the same as that for other wood-pulping processes. The chips are steeped and impregnated with inorganic chemical solutions similar to those used for full chemical pulping, but in smaller amounts and with less severe conditions.…

semicircular canal, any of three loop-shaped organs in the inner ear that help control balance and stability by sensing rotation and orientation of the head in three-dimensional space. The semicircular canals are part of the vestibular system of the inner ear, or labyrinth, which also includes

human ear: Semicircular canals: …its ampulla enclose a membranous semicircular duct of much smaller diameter that has its own ampulla. The membranous ducts and ampullae follow the same pattern as the canals and ampullae of the bony labyrinth, with their openings into the utricle and with a common crus for the superior and posterior…

punctuation: Punctuation in English since 1600: The semicolon (;) ranks halfway between a comma and a full point. It may be substituted for a period between two grammatically complete sentences that are closely connected in sense; in a long or complicated sentence, it may precede a coordinate conjunction (such as or, and,…

semiconductor, any of a class of crystalline solids intermediate in electrical conductivity between a conductor and an insulator. Semiconductors are employed in the manufacture of various kinds of electronic devices, including diodes, transistors, and integrated circuits. Such devices have found

copyright: …programs; a separate statute (the Semiconductor Chip Protection Act of 1984) affords protection for mask works—two- or three-dimensional layout-design patterns for creating layers of integrated circuits—fixed in a semiconductor chip product. (Under certain circumstances, computer programs may receive patent protection.)

solid-state detector, radiation detector in which a semiconductor material such as a silicon or germanium crystal constitutes the detecting medium. One such device consists of a p-n junction across which a pulse of current develops when a particle of ionizing radiation traverses it. In a different

semiconductor device, electronic circuit component made from a material that is neither a good conductor nor a good insulator (hence semiconductor). Such devices have found wide applications because of their compactness, reliability, and low cost. As discrete components, they have found use in

electricity: Electroluminescence: …in a reverse-biased semiconductor p–n junction diode—i.e., a p–n junction diode in which the applied potential is in the direction of small current flow. Electrons in the intense field at the depleted junction easily acquire enough energy to excite atoms. Little of this energy finally emerges as light, though the…

laser: Types of lasers: …widely used lasers today are semiconductor diode lasers, which emit visible or infrared light when an electric current passes through them. The emission occurs at the interface (see p-n junction) between two regions doped with different materials. The p-n junction can act as a laser medium, generating stimulated emission

telecommunications media: Electro-optical transmitters: …a longer lifetime than the semiconductor laser. However, the semiconductor laser couples its light output to the optical fibre much more efficiently than the LED, making it more suitable for longer spans, and it also has a faster “rise” time, allowing higher data transmission rates. Laser diodes are available that…