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211-639: Silicon carbide ( SiC ), also known as carborundum ( / ˌ k ɑːr b ə ˈ r ʌ n d əm / ), is a hard chemical compound containing silicon and carbon . A wide bandgap semiconductor , it occurs in nature as the extremely rare mineral moissanite , but has been mass-produced as a powder and crystal since 1893 for use as an abrasive . Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests . Large single crystals of silicon carbide can be grown by

422-428: A basic oxygen furnace used for making steel , acts as a fuel . The additional energy liberated allows the furnace to process more scrap with the same charge of hot metal. It can also be used to raise tap temperatures and adjust the carbon and silicon content. Silicon carbide is cheaper than a combination of ferrosilicon and carbon, produces cleaner steel and lower emissions due to low levels of trace elements , has

633-502: A calque of the Latin root (e.g. Russian кремний , from кремень "flint"; Greek πυρίτιο from πυρ "fire"; Finnish pii from piikivi "flint", Czech křemík from křemen "quartz", "flint"). Gay-Lussac and Thénard are thought to have prepared impure amorphous silicon in 1811, through the heating of recently isolated potassium metal with silicon tetrafluoride , but they did not purify and characterize

844-402: A carbonaceous chondrite meteorite, has revealed anomalous isotopic ratios of carbon and silicon, indicating that these grains originated outside the solar system. Non-systematic, less-recognized and often unverified syntheses of silicon carbide include: Wide-scale production is credited to Edward Goodrich Acheson in 1891. Acheson was attempting to prepare artificial diamonds when he heated

1055-581: A direct bandgap which favors light emission. However, SiC is still one of the important LED components: It is a popular substrate for growing GaN devices, and it also serves as a heat spreader in high-power LEDs. The low thermal expansion coefficient, high hardness, rigidity and thermal conductivity make silicon carbide a desirable mirror material for astronomical telescopes. The growth technology ( chemical vapor deposition ) has been scaled up to produce disks of polycrystalline silicon carbide up to 3.5 m (11 ft) in diameter, and several telescopes like

1266-655: A famine between 1930 and 1933 that killed millions. The Soviet forced labour camp system of the Gulag was expanded. During the late 1930s, Stalin's government conducted the Great Purge to remove opponents, resulting in mass death, imprisonment, and deportation. In 1939, the USSR and Nazi Germany signed a nonaggression pact , but in 1941, Germany invaded the Soviet Union in the largest land invasion in history, opening

1477-618: A field-effect amplifier made from germanium and silicon, but he failed to build a working device, before eventually working with germanium instead. The first working transistor was a point-contact transistor built by John Bardeen and Walter Brattain later that year while working under Shockley. In 1954, physical chemist Morris Tanenbaum fabricated the first silicon junction transistor at Bell Labs . In 1955, Carl Frosch and Lincoln Derick at Bell Labs accidentally discovered that silicon dioxide ( SiO 2 ) could be grown on silicon. By 1957 Frosch and Derick published their work on

1688-425: A hexagonal close-packed allotrope at about 40  gigapascals known as Si–VII (the standard modification being Si–I). An allotrope called BC8 (or bc8), having a body-centred cubic lattice with eight atoms per primitive unit cell ( space group 206 ), can be created at high pressure and remains metastable at low pressure. Its properties have been studied in detail. Silicon boils at 3265 °C: this, while high,

1899-496: A spark gap . This spark gap is ionized and rendered conductive when lightning raises the voltage of the power line conductor, thus effectively connecting the SiC column between the power conductor and the earth. Spark gaps used in lightning arresters are unreliable, either failing to strike an arc when needed or failing to turn off afterwards, in the latter case due to material failure or contamination by dust or salt. Usage of SiC columns

2110-453: A voltage-dependent resistance , and so columns of SiC pellets were connected between high-voltage power lines and the earth. When a lightning strike to the line raises the line voltage sufficiently, the SiC column will conduct, allowing strike current to pass harmlessly to the earth instead of along the power line. The SiC columns proved to conduct significantly at normal power-line operating voltages and thus had to be placed in series with

2321-467: A zinc blende crystal structure (similar to diamond ), is formed at temperatures below 1,700 °C. Until recently, the beta form has had relatively few commercial uses, although there is now increasing interest in its use as a support for heterogeneous catalysts , owing to its higher surface area compared to the alpha form. Pure SiC is colorless. The brown to black color of the industrial product results from iron impurities. The rainbow-like luster of

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2532-541: A closer relationship with France and Britain. In 1939, half a year after the Munich Agreement , the USSR attempted to form an anti-Nazi alliance with France and Britain. Adolf Hitler proposed a better deal, which would give the USSR control over much of Eastern Europe through the Molotov–Ribbentrop Pact . In September, Germany invaded Poland, and the USSR also invaded later that month, resulting in

2743-410: A common Fermi level; electrons flow from n to p, while holes flow from p to n, creating a voltage drop. This p–n junction thus acts as a diode that can rectify alternating current that allows current to pass more easily one way than the other. A transistor is an n–p–n junction, with a thin layer of weakly p-type silicon between two n-type regions. Biasing the emitter through a small forward voltage and

2954-476: A conductivity (i.e., too high a resistivity ) to be used as a circuit element in electronics. In practice, pure silicon is doped with small concentrations of certain other elements, which greatly increase its conductivity and adjust its electrical response by controlling the number and charge ( positive or negative ) of activated carriers. Such control is necessary for transistors , solar cells , semiconductor detectors , and other semiconductor devices used in

3165-463: A diamond substitute, and may be misidentified as diamond, since its thermal conductivity is closer to diamond than any other substitute. Many thermal diamond-testing devices cannot distinguish moissanite from diamond, but the gem is distinct in its birefringence and a very slight green or yellow fluorescence under ultraviolet light. Some moissanite stones also have curved, string-like inclusions, which diamonds never have. Silicon carbide, dissolved in

3376-402: A ferrosilicon alloy, and only approximately 20% is refined to metallurgical grade purity (a total of 1.3–1.5 million metric tons/year). An estimated 15% of the world production of metallurgical grade silicon is further refined to semiconductor purity. This typically is the "nine-9" or 99.9999999% purity, nearly defect-free single crystalline material. Monocrystalline silicon of such purity

3587-519: A greater union which he initially named as the Union of Soviet Republics of Europe and Asia (Russian: Союз Советских Республик Европы и Азии , romanized : Soyuz Sovyetskikh Respublik Evropy i Azii ). Joseph Stalin initially resisted Lenin's proposal but ultimately accepted it, and with Lenin's agreement he changed the name to the Union of Soviet Socialist Republics (USSR), although all republics began as socialist soviet and did not change to

3798-482: A large family of similar crystalline structures called polytypes. They are variations of the same chemical compound that are identical in two dimensions and differ in the third. Thus, they can be viewed as layers stacked in a certain sequence. Alpha silicon carbide (α-SiC) is the most commonly encountered polymorph , and is formed at temperatures greater than 1,700 °C and has a hexagonal crystal structure (similar to Wurtzite ). The beta modification (β-SiC), with

4009-432: A low gas content, and does not lower the temperature of steel. Silicon Silicon is a chemical element ; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor . It is a member of group 14 in the periodic table: carbon is above it; and germanium , tin , lead , and flerovium are below it. It

4220-522: A manner include polycarbosilanes, poly(methylsilyne) and polysilazanes. Silicon carbide materials obtained through the pyrolysis of preceramic polymers are known as polymer derived ceramics or PDCs. Pyrolysis of preceramic polymers is most often conducted under an inert atmosphere at relatively low temperatures. Relative to the CVD process, the pyrolysis method is advantageous because the polymer can be formed into various shapes prior to thermalization into

4431-449: A mixture of clay (aluminium silicate) and powdered coke (carbon) in an iron bowl. He called the blue crystals that formed carborundum , believing it to be a new compound of carbon and aluminium, similar to corundum . Moissan also synthesized SiC by several routes, including dissolution of carbon in molten silicon, melting a mixture of calcium carbide and silica, and by reducing silica with carbon in an electric furnace. Acheson patented

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4642-597: A new profitable market. In the late 1920s and early 1930s, Stalin ordered Marxist-Leninist parties across the world to strongly oppose non-Marxist political parties, labour unions or other organizations on the left, which they labelled social fascists . In the usage of the Soviet Union, and of the Comintern and its affiliated parties in this period, the epithet fascist was used to describe capitalist society in general and virtually any anti-Soviet or anti-Stalinist activity or opinion. Stalin reversed himself in 1934 with

4853-400: A purely notional figure given the lack of a simple Si cation in reality. At standard temperature and pressure, silicon is a shiny semiconductor with a bluish-grey metallic lustre; as typical for semiconductors, its resistivity drops as temperature rises. This arises because silicon has a small energy gap ( band gap ) between its highest occupied energy levels (the valence band) and

5064-405: A replacement for Zircaloy cladding in light water reactors . One of the reasons for this investigation is that, Zircaloy experiences hydrogen embrittlement as a consequence of the corrosion reaction with water. This produces a reduction in fracture toughness with increasing volumetric fraction of radial hydrides. This phenomenon increases drastically with increasing temperature to the detriment of

5275-405: A slightly colder substrate. This process yields high-quality single crystals, mostly of 6H-SiC phase (because of high growth temperature). A modified Lely process involving induction heating in graphite crucibles yields even larger single crystals of 4 inches (10 cm) in diameter, having a section 81 times larger compared to the conventional Lely process. Cubic SiC is usually grown by

5486-631: A status that is retained by the Russian Federation . Covering a sixth of Earth's land surface, its size was comparable to that of North America . Two other successor states, Kazakhstan and Ukraine , rank among the top 10 countries by land area, and the largest country entirely in Europe, respectively. The European portion accounted for a quarter of the country's area and was the cultural and economic center. The eastern part in Asia extended to

5697-455: A structural complexity unseen in oxocarbons . Silicon tends to resemble germanium far more than it does carbon, and this resemblance is enhanced by the d-block contraction , resulting in the size of the germanium atom being much closer to that of the silicon atom than periodic trends would predict. Nevertheless, there are still some differences because of the growing importance of the divalent state in germanium compared to silicon. Additionally,

5908-542: A structural material for their skeletons. Some plants accumulate silica in their tissues and require silicon for their growth, for example rice . Silicon may be taken up by plants as orthosilicic acid (also known as monosilicic acid) and transported through the xylem , where it forms amorphous complexes with components of the cell wall. This has been shown to improve cell wall strength and structural integrity in some plants, thereby reducing insect herbivory and pathogenic infections. In certain plants, silicon may also upregulate

6119-468: A thin filament in a hot gas stream. Radiative emissions from the filament can be correlated with filament temperature. Filaments are SiC fibers with a diameter of 15 micrometers, about one fifth that of a human hair. Because the fibers are so thin, they do little to disturb the flame and their temperature remains close to that of the local gas. Temperatures of about 800–2,500 K can be measured. References to silicon carbide heating elements exist from

6330-485: A trend toward increasingly complex silicate units with cooling, and the introduction of hydroxide and fluoride anions in addition to oxides. Many metals may substitute for silicon. After these igneous rocks undergo weathering , transport, and deposition, sedimentary rocks like clay, shale, and sandstone are formed. Metamorphism also may occur at high temperatures and pressures, creating an even vaster variety of minerals. There are four sources for silicon fluxes into

6541-475: A union of equals, in practice the Soviet Union was dominated by Russians . The domination was so absolute that for most of its existence, the country was commonly (but incorrectly) referred to as 'Russia'. While the Russian SFSR was technically only one republic within the larger union, it was by far the largest (both in terms of population and area), most powerful, and most highly developed. The Russian SFSR

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6752-568: A woven ceramic made from silicon carbide, with fiber of such small diameter that it can be bundled and spun into a yarn. Due to SiC's exceptional neutron absorption capability, it is used as fuel cladding in nuclear reactors and as nuclear waste containment material. It is also used in producing radiation detectors for monitoring radiation levels in nuclear facilities, environmental monitoring, and medical imaging . Again, SiC sensors and electronics for nuclear reactor applications are being developed potentially for future Martian nuclear power and

6963-581: Is porcelain , which is based on the silicate mineral kaolinite . Traditional glass (silica-based soda–lime glass ) also functions in many of the same ways, and also is used for windows and containers. In addition, specialty silica based glass fibers are used for optical fiber , as well as to produce fiberglass for structural support and glass wool for thermal insulation . Silicones often are used in waterproofing treatments, molding compounds, mold- release agents , mechanical seals, high temperature greases and waxes, and caulking compounds. Silicone

7174-425: Is a deep water Si gradient of greater than 0.3 parts per thousand. Si is most commonly associated with productivity in the oceans. Crystalline bulk silicon is rather inert, but becomes more reactive at high temperatures. Like its neighbour aluminium, silicon forms a thin, continuous surface layer of silicon dioxide ( SiO 2 ) that protects the metal from oxidation. Thus silicon does not measurably react with

7385-432: Is a major structural motif in silicon chemistry just as it is for carbon chemistry. However, the 3p subshell is rather more diffuse than the 2p subshell and does not hybridise so well with the 3s subshell. As a result, the chemistry of silicon and its heavier congeners shows significant differences from that of carbon, and thus octahedral coordination is also significant. For example, the electronegativity of silicon (1.90)

7596-496: Is also sometimes used in breast implants , contact lenses, explosives and pyrotechnics . Silly Putty was originally made by adding boric acid to silicone oil . Other silicon compounds function as high-technology abrasives and new high-strength ceramics based upon silicon carbide . Silicon is a component of some superalloys . Elemental silicon is added to molten cast iron as ferrosilicon or silicocalcium alloys to improve performance in casting thin sections and to prevent

7807-525: Is called "synthetic moissanite" or just "moissanite" after the mineral name. Moissanite is similar to diamond in several important respects: it is transparent and hard (9–9.5 on the Mohs scale , compared to 10 for diamond), with a refractive index between 2.65 and 2.69 (compared to 2.42 for diamond). Moissanite is somewhat harder than common cubic zirconia . Unlike diamond, moissanite can be strongly birefringent . For this reason, moissanite jewels are cut along

8018-428: Is conducted in the presence of scrap iron with low amounts of phosphorus and sulfur , producing ferrosilicon . Ferrosilicon, an iron-silicon alloy that contains varying ratios of elemental silicon and iron, accounts for about 80% of the world's production of elemental silicon, with China, the leading supplier of elemental silicon, providing 4.6 million tonnes (or 2/3rds of world output) of silicon, most of it in

8229-406: Is created when heat produces free electrons and holes, which in turn pass more current, which produces more heat). In addition, the insulating oxide of silicon is not soluble in water, which gives it an advantage over germanium (an element with similar properties which can also be used in semiconductor devices) in certain fabrication techniques. Monocrystalline silicon is expensive to produce, and

8440-453: Is deposited in many plant tissues. Owing to the abundance of silicon in the Earth's crust , natural silicon-based materials have been used for thousands of years. Silicon rock crystals were familiar to various ancient civilizations , such as the predynastic Egyptians who used it for beads and small vases , as well as the ancient Chinese . Glass containing silica was manufactured by

8651-484: Is deposited into the world's oceans each year. Of that value, 80–240 megatonnes are in the form of particulate silicon. The total amount of particulate silicon deposition into the ocean is still less than the amount of silicon influx into the ocean via riverine transportation. Aeolian inputs of particulate lithogenic silicon into the North Atlantic and Western North Pacific oceans are the result of dust settling on

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8862-573: Is derived from the Russian word sovet (Russian: совет ), meaning 'council', 'assembly', 'advice', ultimately deriving from the proto-Slavic verbal stem of * vět-iti ('to inform'), related to Slavic věst ('news'), English wise . The word sovietnik means 'councillor'. Some organizations in Russian history were called council (Russian: совет ). In the Russian Empire ,

9073-524: Is easily produced on Si surfaces by processes of thermal oxidation or local oxidation (LOCOS) , which involve exposing the element to oxygen under the proper conditions that can be predicted by the Deal–Grove model . Silicon has become the most popular material for both high power semiconductors and integrated circuits because it can withstand the highest temperatures and greatest electrical activity without suffering avalanche breakdown (an electron avalanche

9284-534: Is essential to the transistors and integrated circuit chips used in most modern technology such as smartphones and other computers . In 2019, 32.4% of the semiconductor market segment was for networks and communications devices, and the semiconductors industry is projected to reach $ 726.73 billion by 2027. Silicon is an essential element in biology. Only traces are required by most animals, but some sea sponges and microorganisms, such as diatoms and radiolaria , secrete skeletal structures made of silica. Silica

9495-435: Is highly exothermic and hence requires no outside energy source. Hyperfine silicon is made at a higher purity than almost any other material: transistor production requires impurity levels in silicon crystals less than 1 part per 10 , and in special cases impurity levels below 1 part per 10 are needed and attained. Silicon nanostructures can directly be produced from silica sand using conventional metalothermic processes, or

9706-655: Is his background, his education , his profession . These are the questions that will determine the fate of the accused. That is the meaning and essence of the Red Terror ." During his rule, Stalin always made the final policy decisions. Otherwise, Soviet foreign policy was set by the commission on the Foreign Policy of the Central Committee of the Communist Party of the Soviet Union , or by

9917-469: Is however observed for the magnetic field behavior between aluminium and boron doping: 3C-SiC:Al is type-II . In contrast, 3C-SiC:B is type-I , as is 6H-SiC:B. Thus the superconducting properties seem to depend more on dopant (B vs. Al) than on polytype (3C- vs 6H-). In an attempt to explain this dependence, it was noted that B substitutes at C sites in SiC, but Al substitutes at Si sites. Therefore, Al and B "see" different environments, in both polytypes. In

10128-430: Is largely composed of carbon , but astrobiology considers that extraterrestrial life may have other hypothetical types of biochemistry . Silicon is considered an alternative to carbon, as it can create complex and stable molecules with four covalent bonds, required for a DNA -analog, and it is available in large quantities. Soviet Union The Union of Soviet Socialist Republics ( USSR ), commonly known as

10339-470: Is much less than that of carbon (2.55), because the valence electrons of silicon are further from the nucleus than those of carbon and hence experience smaller electrostatic forces of attraction from the nucleus. The poor overlap of 3p orbitals also results in a much lower tendency toward catenation (formation of Si–Si bonds) for silicon than for carbon, due to the concomitant weakening of the Si–Si bond compared to

10550-524: Is of use in NMR and EPR spectroscopy , as it is the only one with a nuclear spin ( I = ⁠ 1 / 2 ⁠ ). All three are produced in Type Ia supernovae through the oxygen-burning process , with Si being made as part of the alpha process and hence the most abundant. The fusion of Si with alpha particles by photodisintegration rearrangement in stars is known as the silicon-burning process ; it

10761-462: Is projected, beginning with a large plant opened 2022 by Wolfspeed , in upstate New York. The phenomenon of electroluminescence was discovered in 1907 using silicon carbide and some of the first commercial LEDs were based on this material. When General Electric of America introduced its SSL-1 Solid State Lamp in March 1967, using a tiny chip of semi-conducting SiC to emit a point of yellow light, it

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10972-567: Is relatively unreactive. Silicon is a significant element that is essential for several physiological and metabolic processes in plants. Silicon is widely regarded as the predominant semiconductor material due to its versatile applications in various electrical devices such as transistors, solar cells, integrated circuits, and others. These may be due to its significant band gap, expansive optical transmission range, extensive absorption spectrum, surface roughening, and effective anti-reflection coating. Because of its high chemical affinity for oxygen, it

11183-507: Is still lower than the temperature at which its lighter congener carbon sublimes (3642 °C) and silicon similarly has a lower heat of vaporisation than carbon, consistent with the fact that the Si–Si bond is weaker than the C–C bond. It is also possible to construct silicene layers analogous to graphene . Naturally occurring silicon is composed of three stable isotopes , Si (92.23%), Si (4.67%), and Si (3.10%). Out of these, only Si

11394-518: Is the basis of the widely used synthetic polymers called silicones . The late 20th century to early 21st century has been described as the Silicon Age (also known as the Digital Age or Information Age ) because of the large impact that elemental silicon has on the modern world economy. The small portion of very highly purified elemental silicon used in semiconductor electronics (<15%)

11605-411: Is the last stage of stellar nucleosynthesis before the rapid collapse and violent explosion of the star in question in a type II supernova . Twenty-two radioisotopes have been characterized, the two stablest being Si with a half-life of about 150 years, and Si with a half-life of 2.62 hours. All the remaining radioactive isotopes have half-lives that are less than seven seconds, and

11816-508: Is the non-toxic, metal-free nature of silicon. Another application of silicon quantum dots is for sensing of hazardous materials. The sensors take advantage of the luminescent properties of the quantum dots through quenching of the photoluminescence in the presence of the hazardous substance. There are many methods used for hazardous chemical sensing with a few being electron transfer, fluorescence resonance energy transfer , and photocurrent generation. Electron transfer quenching occurs when

12027-497: Is used as a support and shelving material in high temperature kilns such as for firing ceramics, glass fusing, or glass casting. SiC kiln shelves are considerably lighter and more durable than traditional alumina shelves. In December 2015, infusion of silicon carbide nano-particles in molten magnesium was mentioned as a way to produce a new strong and plastic alloy suitable for use in aeronautics, aerospace, automobile and micro-electronics. Silicon-infiltrated carbon-carbon composite

12238-629: Is used for high performance "ceramic" brake discs , as they are able to withstand extreme temperatures. The silicon reacts with the graphite in the carbon-carbon composite to become carbon-fiber-reinforced silicon carbide (C/SiC). These brake discs are used on some road-going sports cars, supercars, as well as other performance cars including the Porsche Carrera GT , the Bugatti Veyron , the Chevrolet Corvette ZR1 ,

12449-532: Is used in building mortar and modern stucco , but more importantly, combined with silica sand, and gravel (usually containing silicate minerals such as granite), to make the concrete that is the basis of most of the very largest industrial building projects of the modern world. Silica is used to make fire brick , a type of ceramic. Silicate minerals are also in whiteware ceramics , an important class of products usually containing various types of fired clay minerals (natural aluminium phyllosilicates). An example

12660-616: Is used in composite armor (e.g. Chobham armor ), and in ceramic plates in bulletproof vests. Dragon Skin , which was produced by Pinnacle Armor , used disks of silicon carbide. Improved fracture toughness in SiC armor can be facilitated through the phenomenon of abnormal grain growth or AGG. The growth of abnormally long silicon carbide grains may serve to impart a toughening effect through crack-wake bridging, similar to whisker reinforcement. Similar AGG-toughening effects have been reported in Silicon nitride (Si 3 N 4 ). Silicon carbide

12871-486: Is used in the chemical industry. However, even greater purity is needed for semiconductor applications, and this is produced from the reduction of tetrachlorosilane (silicon tetrachloride) or trichlorosilane . The former is made by chlorinating scrap silicon and the latter is a byproduct of silicone production. These compounds are volatile and hence can be purified by repeated fractional distillation , followed by reduction to elemental silicon with very pure zinc metal as

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13082-618: Is usually justified only in production of integrated circuits, where tiny crystal imperfections can interfere with tiny circuit paths. For other uses, other types of pure silicon may be employed. These include hydrogenated amorphous silicon and upgraded metallurgical-grade silicon (UMG-Si) used in the production of low-cost, large-area electronics in applications such as liquid crystal displays and of large-area, low-cost, thin-film solar cells . Such semiconductor grades of silicon are either slightly less pure or polycrystalline rather than monocrystalline, and are produced in comparable quantities as

13293-521: Is usually produced by the Czochralski process , and is used to produce silicon wafers used in the semiconductor industry , in electronics, and in some high-cost and high-efficiency photovoltaic applications. Pure silicon is an intrinsic semiconductor , which means that unlike metals, it conducts electron holes and electrons released from atoms by heat; silicon's electrical conductivity increases with higher temperatures. Pure silicon has too low

13504-520: The Council of People's Commissars ), headed by the Chairman (Premier) and managing an enormous bureaucracy responsible for the administration of the economy and society. State and party structures of the constituent republics largely emulated the structure of the central institutions, although the Russian SFSR, unlike the other constituent republics, for most of its history had no republican branch of

13715-606: The Eastern Front of World War II . The Soviets played a decisive role in defeating the Axis powers , suffering an estimated 27 million casualties , which accounted for most Allied losses. In the aftermath of the war , the Soviet Union consolidated the territory occupied by the Red Army , forming satellite states , and undertook rapid economic development which cemented its status as a superpower . Geopolitical tensions with

13926-467: The Egyptians since at least 1500 BC, as well as by the ancient Phoenicians . Natural silicate compounds were also used in various types of mortar for construction of early human dwellings . In 1787, Antoine Lavoisier suspected that silica might be an oxide of a fundamental chemical element , but the chemical affinity of silicon for oxygen is high enough that he had no means to reduce

14137-528: The Herschel Space Telescope are already equipped with SiC optics, as well the Gaia space observatory spacecraft subsystems are mounted on a rigid silicon carbide frame, which provides a stable structure that will not expand or contract due to heat. Silicon carbide fibers are used to measure gas temperatures in an optical technique called thin-filament pyrometry. It involves the placement of

14348-755: The Land Forces , the Air Force , the Navy , Joint State Political Directorate (OGPU) and the Internal Troops . The OGPU later became independent and in 1934 joined the NKVD secret police, and so its internal troops were under the joint leadership of the defense and internal commissariats. After World War II, Strategic Missile Forces (1959), Air Defense Forces (1948) and National Civil Defense Forces (1970) were formed, which ranked first, third, and sixth in

14559-547: The Lely method and they can be cut into gems known as synthetic moissanite. Electronic applications of silicon carbide such as light-emitting diodes (LEDs) and detectors in early radios were first demonstrated around 1907. SiC is used in semiconductor electronics devices that operate at high temperatures or high voltages, or both. Naturally occurring moissanite is found in only minute quantities in certain types of meteorite , corundum deposits, and kimberlite . Virtually all

14770-463: The McLaren P1 , Bentley , Ferrari , Lamborghini and some specific high-performance Audi cars. Silicon carbide is also used in a sintered form for diesel particulate filters . It is also used as an oil additive to reduce friction, emissions, and harmonics. SiC is used in crucibles for holding melting metal in small and large foundry applications. The earliest electrical application of SiC

14981-528: The Moscow State Institute of International Relations . The Marxist-Leninist leadership of the Soviet Union intensely debated foreign policy issues and changed directions several times. Even after Stalin assumed dictatorial control in the late 1920s, there were debates, and he frequently changed positions. During the country's early period, it was assumed that Communist revolutions would break out soon in every major industrial country, and it

15192-657: The Pacific Ocean to the east and Afghanistan to the south, and, except some areas in Central Asia , was much less populous. It spanned over 10,000 kilometres (6,200 mi) east to west across 11 time zones , and over 7,200 kilometres (4,500 mi) north to south. It had five climate zones: tundra , taiga , steppes , desert and mountains . The USSR, like Russia , had the world's longest border , measuring over 60,000 kilometres (37,000 mi), or 1 + 1 ⁄ 2 circumferences of Earth. Two-thirds of it

15403-790: The Popular Front program that called on all Marxist parties to join with all anti-Fascist political, labour, and organizational forces that were opposed to fascism , especially of the Nazi variety. The rapid growth of power in Nazi Germany encouraged both Paris and Moscow to form a military alliance, and the Franco-Soviet Treaty of Mutual Assistance was signed in May 1935. A firm believer in collective security, Stalin's foreign minister Maxim Litvinov worked very hard to form

15614-464: The Soviet Union , was a transcontinental country that spanned much of Eurasia from 1922 to 1991. During its existence, it was the largest country by area , extending across eleven time zones and sharing borders with twelve countries , and the third-most populous country . An overall successor to the Russian Empire , it was nominally organized as a federal union of national republics ,

15825-563: The Soviet Union , in 1923. Because natural moissanite is extremely scarce, most silicon carbide is synthetic. Silicon carbide is used as an abrasive, as well as a semiconductor and diamond simulant of gem quality. The simplest process to manufacture silicon carbide is to combine silica sand and carbon in an Acheson graphite electric resistance furnace at a high temperature, between 1,600 °C (2,910 °F) and 2,500 °C (4,530 °F). Fine SiO 2 particles in plant material (e.g. rice husks) can be converted to SiC by heating in

16036-581: The Soviet republics , and the control of the Communist Party weakened. The failed coup attempt in August 1991 against Gorbachev by hardline communists hastened the end of the Soviet Union , which formally dissolved on December 26, 1991, ending nearly seven decades of Soviet rule. With an area of 22,402,200 square kilometres (8,649,500 sq mi), the Soviet Union was the world's largest country,

16247-772: The State Council , which functioned from 1810 to 1917, was referred to as a Council of Ministers. The Soviets as workers' councils first appeared during the 1905 Russian Revolution . Although they were quickly suppressed by the Imperial army, after the February Revolution of 1917 , workers' and soldiers' Soviets emerged throughout the country and shared power with the Russian Provisional Government . The Bolsheviks, led by Vladimir Lenin , demanded that all power be transferred to

16458-635: The Universal Declaration of Human Rights (1948), saying that it was "overly juridical" and potentially infringed on national sovereignty. The Soviet Union later signed legally-binding human rights documents, such as the International Covenant on Civil and Political Rights in 1973 (and the 1966 International Covenant on Economic, Social and Cultural Rights ), but they were neither widely known or accessible to people living under Communist rule, nor were they taken seriously by

16669-446: The automotive industry . Silicon's importance in aluminium casting is that a significantly high amount (12%) of silicon in aluminium forms a eutectic mixture which solidifies with very little thermal contraction. This greatly reduces tearing and cracks formed from stress as casting alloys cool to solidity. Silicon also significantly improves the hardness and thus wear-resistance of aluminium. Most elemental silicon produced remains as

16880-746: The halogens ; fluorine attacks silicon vigorously at room temperature, chlorine does so at about 300 °C, and bromine and iodine at about 500 °C. Silicon does not react with most aqueous acids, but is oxidised and complexed by hydrofluoric acid mixtures containing either chlorine or nitric acid to form hexafluorosilicates . It readily dissolves in hot aqueous alkali to form silicates . At high temperatures, silicon also reacts with alkyl halides ; this reaction may be catalysed by copper to directly synthesise organosilicon chlorides as precursors to silicone polymers. Upon melting, silicon becomes extremely reactive, alloying with most metals to form silicides , and reducing most metal oxides because

17091-489: The heat of formation of silicon dioxide is so large. In fact, molten silicon reacts virtually with every known kind of crucible material (except its own oxide, SiO 2 ). This happens due to silicon's high binding forces for the light elements and to its high dissolving power for most elements. As a result, containers for liquid silicon must be made of refractory , unreactive materials such as zirconium dioxide or group 4, 5, and 6 borides. Tetrahedral coordination

17302-769: The largest arsenal of nuclear weapons in the world . As an Allied nation, it was a founding member of the United Nations as well as one of the five permanent members of the United Nations Security Council . Before its dissolution, the USSR was one of the world's two superpowers through its hegemony in Eastern Europe, global diplomatic and ideological influence (particularly in the Global South ), military and economic strengths, and scientific accomplishments. The word soviet

17513-418: The lowest unoccupied molecular orbital (LUMO) is slightly lower in energy than the conduction band of the quantum dot, allowing for the transfer of electrons between the two, preventing recombination of the holes and electrons within the nanocrystals. The effect can also be achieved in reverse with a donor molecule having its highest occupied molecular orbital (HOMO) slightly higher than a valence band edge of

17724-455: The mantle makes up 68.1% of the Earth's mass and is composed mostly of denser oxides and silicates, an example being olivine , (Mg,Fe) 2 SiO 4 ; while the lighter siliceous minerals such as aluminosilicates rise to the surface and form the crust, making up 0.4% of the Earth's mass. The crystallisation of igneous rocks from magma depends on a number of factors; among them are

17935-465: The optic axis of the crystal to minimize birefringent effects. It is lighter (density 3.21 g/cm vs. 3.53 g/cm), and much more resistant to heat than diamond. This results in a stone of higher luster , sharper facets, and good resilience. Loose moissanite stones may be placed directly into wax ring moulds for lost-wax casting, as can diamond, as moissanite remains undamaged by temperatures up to 1,800 °C (3,270 °F). Moissanite has become popular as

18146-409: The photocurrent emitted by the quantum dots instead of monitoring the photoluminescent display. If the concentration of the desired chemical increases then the photocurrent given off by the nanocrystals will change in response. Although silicon is readily available in the form of silicates , very few organisms use it directly. Diatoms , radiolaria , and siliceous sponges use biogenic silica as

18357-538: The right to food , the right to work , and the right to education . The Soviet conception of human rights was very different from international law . According to Soviet legal theory , "it is the government who is the beneficiary of human rights which are to be asserted against the individual". The Soviet state was considered as the source of human rights. Therefore, the Soviet legal system considered law an arm of politics and it also considered courts agencies of

18568-703: The 1920s, it refused to rubber stamp proposals from the party and Council of Ministers. In 1990, Gorbachev introduced and assumed the position of the President of the Soviet Union , concentrated power in his executive office, independent of the party, and subordinated the government, now renamed the Cabinet of Ministers of the USSR , to himself. Tensions grew between the Union-wide authorities under Gorbachev, reformists led in Russia by Boris Yeltsin and controlling

18779-482: The 1950s, the Soviet Union expanded its efforts in space exploration and took a lead in the Space Race with the first artificial satellite , the first human spaceflight , the first space station , and the first probe to land on another planet . In 1985, the last Soviet leader, Mikhail Gorbachev , sought to reform the country through his policies of glasnost and perestroika . In 1989, various countries of

18990-601: The 1990s, people in the West were also interested in the radioactive hazards of nuclear facilities, decommissioned nuclear submarines , and the processing of nuclear waste or spent nuclear fuel . It was also known in the early 1990s that the USSR had transported radioactive material to the Barents Sea and Kara Sea , which was later confirmed by the Russian parliament. The crash of the K-141 Kursk submarine in 2000 in

19201-595: The 20th century saw the development of the chemistry and industrial use of siloxanes and the growing use of silicone polymers , elastomers , and resins . In the late 20th century, the complexity of the crystal chemistry of silicides was mapped, along with the solid-state physics of doped semiconductors . The first semiconductor devices did not use silicon, but used galena , including German physicist Ferdinand Braun 's crystal detector in 1874 and Indian physicist Jagadish Chandra Bose 's radio crystal detector in 1901. The first silicon semiconductor device

19412-526: The CPSU, being ruled directly by the union-wide party until 1990. Local authorities were organized likewise into party committees , local Soviets and executive committees . While the state system was nominally federal, the party was unitary. The state security police (the KGB and its predecessor agencies ) played an important role in Soviet politics. It was instrumental in the Red Terror and Great Purge , but

19623-529: The Communist authorities. Under Joseph Stalin , the death penalty was extended to adolescents as young as 12 years old in 1935. Sergei Kovalev recalled "the famous article 125 of the Constitution which enumerated all basic civil and political rights" in the Soviet Union. But when he and other prisoners attempted to use this as a legal basis for their abuse complaints, their prosecutor's argument

19834-533: The C–C bond: the average Si–Si bond energy is approximately 226 kJ/mol, compared to a value of 356 kJ/mol for the C–C bond. This results in multiply bonded silicon compounds generally being much less stable than their carbon counterparts, an example of the double bond rule . On the other hand, the presence of radial nodes in the 3p orbitals of silicon suggests the possibility of hypervalence , as seen in five and six-coordinate derivatives of silicon such as SiX 5 and SiF 6 . Lastly, because of

20045-535: The Earth's crust is composed of silicate minerals , which are compounds of silicon and oxygen, often with metallic ions when negatively charged silicate anions require cations to balance the charge. Many of these have direct commercial uses, such as clays, silica sand, and most kinds of building stone. Thus, the vast majority of uses for silicon are as structural compounds, either as the silicate minerals or silica (crude silicon dioxide). Silicates are used in making Portland cement (made mostly of calcium silicates) which

20256-538: The Politburo after the deaths of Lenin and Stalin, as well as after Khrushchev's dismissal, itself due to a decision by both the Politburo and the Central Committee. All leaders of the Communist Party before Gorbachev died in office, except Georgy Malenkov and Khrushchev, both dismissed from the party leadership amid internal struggle within the party. Between 1988 and 1990, facing considerable opposition, Mikhail Gorbachev enacted reforms shifting power away from

20467-736: The Russian Soviet Federative Socialist Republic (RSFSR), the world's first constitutionally socialist state . The revolution was not accepted by all within the Russian Republic , resulting in the Russian Civil War . The RSFSR and its subordinate republics were merged into the Soviet Union in 1922. Following Lenin's death in 1924, Joseph Stalin came to power, inaugurating rapid industrialization and forced collectivization that led to significant economic growth but contributed to

20678-475: The Russian name of the Soviet Union as СС has been taboo, the reason being that СС as a Russian Cyrillic abbreviation is associated with the infamous Schutzstaffel of Nazi Germany , as SS is in English. In English-language media, the state was referred to as the Soviet Union or the USSR. The Russian SFSR dominated the Soviet Union to such an extent that, for most of the Soviet Union's existence, it

20889-580: The Soviet Union and turned into SSRs, which was not recognized by most of the international community and was considered an illegal occupation . After the Soviet invasion of Finland , the Karelo-Finnish SSR was formed on annexed territory as a Union Republic in March 1940 and then incorporated into Russia as the Karelian ASSR in 1956. Between July 1956 and September 1991, there were 15 union republics (see map below). While nominally

21100-529: The Soviet Union . Boris Yeltsin , the leader of the RSFSR, oversaw its reconstitution into the Russian Federation , which became the Soviet Union's successor state; all other republics emerged as fully independent post-Soviet states . During its existence, the Soviet Union produced many significant social and technological achievements and innovations . It had the world's second-largest economy and largest standing military. An NPT-designated state , it wielded

21311-662: The Soviet Union's priorities changed. Despite previous conflict with the United Kingdom , Vyacheslav Molotov dropped his post war border demands. The Cold War was a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc , which began following World War II in 1945. The term cold war is used because there

21522-541: The Soviet Union's superpower status, the economy struggled due to its centralized nature, technological backwardness, and inefficiencies. The vast military expenditures and burdens of maintaining the Eastern Bloc, further strained the Soviet economy. In the 1980s, Mikhail Gorbachev 's policies of Glasnost (openness) and Perestroika (restructuring) aimed to revitalize the Soviet system but instead accelerated its unraveling. Nationalist movements gained momentum across

21733-546: The Soviet authorities admitted. The Soviet Union was the world's second largest producer of harmful emissions. In 1988, total emissions in the Soviet Union were about 79% of those in the United States. But since the Soviet GNP was only 54% of that of the United States, this means that the Soviet Union generated 1.5 times more pollution than the United States per unit of GNP. The Soviet Chernobyl disaster in 1986

21944-825: The Soviets, and gained support from the workers and soldiers. After the October Revolution , in which the Bolsheviks seized power from the Provisional Government in the name of the Soviets, Lenin proclaimed the formation of the Russian Socialist Federal Soviet Republic (RSFSR). During the Georgian Affair of 1922, Lenin called for the Russian SFSR and other national Soviet republics to form

22155-536: The Supreme Soviet were members of the CPSU. Of the party heads themselves, Stalin (1941–1953) and Khrushchev (1958–1964) were Premiers. Upon the forced retirement of Khrushchev, the party leader was prohibited from this kind of double membership, but the later General Secretaries for at least some part of their tenure occupied the mostly ceremonial position of Chairman of the Presidium of the Supreme Soviet ,

22366-713: The US led to the Cold War . The American-led Western Bloc coalesced into NATO in 1949, prompting the Soviet Union to form its own military alliance, the Warsaw Pact , in 1955. Neither side engaged in direct military confrontation, and instead fought on an ideological basis and through proxy wars . In 1953, following Stalin's death , the Soviet Union undertook a campaign of de-Stalinization under Nikita Khrushchev , which saw reversals and rejections of Stalinist policies. This campaign caused tensions with Communist China . During

22577-430: The USSR. Moscow eventually stopped threatening other states, and instead worked to open peaceful relationships in terms of trade, and diplomatic recognition. The United Kingdom dismissed the warnings of Winston Churchill and a few others about a continuing Marxist-Leninist threat, and opened trade relations and de facto diplomatic recognition in 1922. There was hope for a settlement of the pre-war Tsarist debts, but it

22788-469: The Warsaw Pact overthrew their Soviet-backed regimes , and nationalist and separatist movements erupted across the Soviet Union. In 1991, amid efforts to preserve the country as a renewed federation , an attempted coup against Gorbachev by hardline communists prompted the largest republics—Ukraine, Russia, and Belarus—to secede. On December 26, Gorbachev officially recognized the dissolution of

22999-503: The accident, but this led to a relatively low number of deaths (WHO data, 2005). Another major radioactive accident was the Kyshtym disaster . The Kola Peninsula was one of the places with major problems. Around the industrial cities of Monchegorsk and Norilsk , where nickel , for example, is mined, all forests have been destroyed by contamination, while the northern and other parts of Russia have been affected by emissions. During

23210-399: The air below 900 °C, but formation of the vitreous dioxide rapidly increases between 950 °C and 1160 °C and when 1400 °C is reached, atmospheric nitrogen also reacts to give the nitrides SiN and Si 3 N 4 . Silicon reacts with gaseous sulfur at 600 °C and gaseous phosphorus at 1000 °C. This oxide layer nevertheless does not prevent reaction with

23421-452: The arts, silicon carbide is a popular abrasive in modern lapidary due to the durability and low cost of the material. In manufacturing, it is used for its hardness in abrasive machining processes such as grinding , honing , water-jet cutting and sandblasting . SiC provides a much sharper and harder alternative for sand blasting as compared to aluminium oxide . Particles of silicon carbide are laminated to paper to create sandpapers and

23632-408: The behavior of its oxide compounds and its reaction with acids as well as bases (though this takes some effort), and is hence often referred to as a metalloid rather than a nonmetal. Germanium shows more, and tin is generally considered a metal. Silicon shows clear differences from carbon. For example, organic chemistry has very few analogies with silicon chemistry, while silicate minerals have

23843-498: The capabilities of SiC power devices are: Beginning with Tesla Model 3 the inverters in the drive unit use 24 pairs of silicon carbide (SiC) MOSFET chips rated for 650 volts each. Silicon carbide in this instance gave Tesla a significant advantage over chips made of silicon in terms of size and weight. A number of automobile manufacturers are planning to incorporate silicon carbide into power electronic devices in their products. A significant increase in production of silicon carbide

24054-584: The central silicon atom shares an electron pair with each of the four atoms it is bonded to. The first four ionisation energies of silicon are 786.3, 1576.5, 3228.3, and 4354.4 kJ/mol respectively; these figures are high enough to preclude the possibility of simple cationic chemistry for the element. Following periodic trends , its single-bond covalent radius of 117.6 pm is intermediate between those of carbon (77.2 pm) and germanium (122.3 pm). The hexacoordinate ionic radius of silicon may be considered to be 40 pm, although this must be taken as

24265-409: The ceramic. SiC can also be made into wafers by cutting a single crystal either using a diamond wire saw or by using a laser. SiC is a useful semiconductor used in power electronics. Silicon carbide exists in about 250 crystalline forms. Through inert atmospheric pyrolysis of preceramic polymers , silicon carbide in a glassy amorphous form is also produced. The polymorphism of SiC is characterized by

24476-418: The chemical composition of the magma, the cooling rate, and some properties of the individual minerals to be formed, such as lattice energy , melting point, and complexity of their crystal structure. As magma is cooled, olivine appears first, followed by pyroxene , amphibole , biotite mica, orthoclase feldspar , muscovite mica , quartz , zeolites , and finally, hydrothermal minerals. This sequence shows

24687-418: The collector through a large reverse voltage allows the transistor to act as a triode amplifier. Silicon crystallises in a giant covalent structure at standard conditions, specifically in a diamond cubic crystal lattice ( space group 227 ). It thus has a high melting point of 1414 °C, as a lot of energy is required to break the strong covalent bonds and melt the solid. Upon melting silicon contracts as

24898-410: The combustion synthesis approach. Such nanostructured silicon materials can be used in various functional applications including the anode of lithium-ion batteries (LIBs), other ion batteries, future computing devices like memristors or photocatalytic applications. Most silicon is used industrially without being purified, often with comparatively little processing from its natural form. More than 90% of

25109-400: The computer industry and other technical applications. In silicon photonics , silicon may be used as a continuous wave Raman laser medium to produce coherent light. In common integrated circuits , a wafer of monocrystalline silicon serves as a mechanical support for the circuits, which are created by doping and insulated from each other by thin layers of silicon oxide , an insulator that

25320-411: The conduction band either thermally or photolytically, creating an n-type semiconductor . Similarly, doping silicon with a group 13 element such as boron , aluminium , or gallium results in the introduction of acceptor levels that trap electrons that may be excited from the filled valence band, creating a p-type semiconductor . Joining n-type silicon to p-type silicon creates a p–n junction with

25531-429: The country was limited. The state restricted rights of citizens to private property . According to the Universal Declaration of Human Rights , human rights are the "basic rights and freedoms to which all humans are entitled." including the right to life and liberty , freedom of expression , and equality before the law ; and social, cultural and economic rights, including the right to participate in culture ,

25742-716: The creation of new state commissions and committees. It gained additional powers relating to the approval of the Five-Year Plans and the government budget . The Supreme Soviet elected a Presidium (successor of the Central Executive Committee ) to wield its power between plenary sessions, ordinarily held twice a year, and appointed the Supreme Court , the Procurator General and the Council of Ministers (known before 1946 as

25953-437: The crystals is due to the thin-film interference of a passivation layer of silicon dioxide that forms on the surface. The high sublimation temperature of SiC (approximately 2,700 °C) makes it useful for bearings and furnace parts. Silicon carbide does not melt but begins to sublimate near 2,700 °C like graphite, having an appreciable vapor pressure near that temp. It is also highly inert chemically, partly due to

26164-532: The degree of power consolidation, it was either the Politburo as a collective body or the General Secretary, who always was one of the Politburo members, that effectively led the party and the country (except for the period of the highly personalized authority of Stalin, exercised directly through his position in the Council of Ministers rather than the Politburo after 1941). They were not controlled by

26375-534: The development of SiC-based power MOSFETs and insulated-gate bipolar transistors . Although the mechanism is still unclear, nitriding has dramatically reduced the defects causing the interface problems. In 2008, the first commercial JFETs rated at 1,200 V were introduced to the market, followed in 2011 by the first commercial MOSFETs rated at 1200 V. JFETs are now available rated 650 V to 1,700 V with resistance as low as 25 mΩ. Beside SiC switches and SiC Schottky diodes (also Schottky barrier diode, SBD ) in

26586-1763: The dominant materials during their respective ages of civilization . Because silicon is an important element in high-technology semiconductor devices, many places in the world bear its name. For example, the Santa Clara Valley in California acquired the nickname Silicon Valley , as the element is the base material in the semiconductor industry there. Since then, many other places have been similarly dubbed, including Silicon Wadi in Israel; Silicon Forest in Oregon; Silicon Hills in Austin, Texas; Silicon Slopes in Salt Lake City, Utah; Silicon Saxony in Germany; Silicon Valley in India; Silicon Border in Mexicali, Mexico; Silicon Fen in Cambridge, England; Silicon Roundabout in London; Silicon Glen in Scotland; Silicon Gorge in Bristol, England; Silicon Alley in New York City; and Silicon Beach in Los Angeles. A silicon atom has fourteen electrons . In

26797-553: The duty of the Russian Bolsheviks to protect what they had in Russia, and avoid military confrontations that might destroy their bridgehead. Russia was now a pariah state, along with Germany. The two came to terms in 1922 with the Treaty of Rapallo that settled long-standing grievances. At the same time, the two countries secretly set up training programs for the illegal German army and air force operations at hidden camps in

27008-581: The early 20th century when they were produced by Acheson's Carborundum Co. in the U.S. and EKL in Berlin. Silicon carbide offered increased operating temperatures compared with metallic heaters. Silicon carbide elements are used today in the melting of glass and non-ferrous metal, heat treatment of metals, float glass production, production of ceramics and electronics components, igniters in pilot lights for gas heaters, etc. The outer thermal protection layer of NASA's LOFTID inflatable heat shield incorporates

27219-437: The elimination of defects: edge dislocations, screw dislocations (both hollow and closed core), triangular defects and basal plane dislocations. As a result, devices made of SiC crystals initially displayed poor reverse blocking performance, though researchers have been tentatively finding solutions to improve the breakdown performance. Apart from crystal quality, problems with the interface of SiC with silicon dioxide have hampered

27430-573: The emerging terrestrial micro nuclear power plants. Silicon carbide is an important material in TRISO -coated fuel particles, the type of nuclear fuel found in high temperature gas cooled reactors such as the Pebble Bed Reactor . A layer of silicon carbide gives coated fuel particles structural support and is the main diffusion barrier to the release of fission products. Silicon carbide composite material has been investigated for use as

27641-498: The emitted electron carries up to 1.48  MeV of energy. The known isotopes of silicon range in mass number from 22 to 46. The most common decay mode of the isotopes with mass numbers lower than the three stable isotopes is inverse beta decay , primarily forming aluminium isotopes (13 protons) as decay products . The most common decay mode for the heavier unstable isotopes is beta decay, primarily forming phosphorus isotopes (15 protons) as decay products. Silicon can enter

27852-461: The excess carbon from the organic material. The silica fume , which is a byproduct of producing silicon metal and ferrosilicon alloys, can also be converted to SiC by heating with graphite at 1,500 °C (2,730 °F). The material formed in the Acheson furnace varies in purity, according to its distance from the graphite resistor heat source . Colorless, pale yellow and green crystals have

28063-497: The first manufactured SiO 2 semiconductor oxide transistor: the first planar transistors, in which drain and source were adjacent at the same surface. The "Silicon Age" refers to the late 20th century to early 21st century. This is due to silicon being the dominant material of the Silicon Age (also known as the Digital Age or Information Age ), similar to how the Stone Age , Bronze Age and Iron Age were defined by

28274-408: The first volatile hydrides of silicon, synthesising trichlorosilane in 1857 and silane itself in 1858, but a detailed investigation of the silanes was only carried out in the early 20th century by Alfred Stock , despite early speculation on the matter dating as far back as the beginnings of synthetic organic chemistry in the 1830s. Similarly, the first organosilicon compound , tetraethylsilane,

28485-515: The form of ferrosilicon. It is followed by Russia (610,000 t), Norway (330,000 t), Brazil (240,000 t), and the United States (170,000 t). Ferrosilicon is primarily used by the iron and steel industry (see below ) with primary use as alloying addition in iron or steel and for de-oxidation of steel in integrated steel plants. Another reaction, sometimes used, is aluminothermal reduction of silicon dioxide, as follows: Leaching powdered 96–97% pure silicon with water results in ~98.5% pure silicon, which

28696-418: The formation of cementite where exposed to outside air. The presence of elemental silicon in molten iron acts as a sink for oxygen, so that the steel carbon content, which must be kept within narrow limits for each type of steel, can be more closely controlled. Ferrosilicon production and use is a monitor of the steel industry, and although this form of elemental silicon is grossly impure, it accounts for 80% of

28907-465: The formation of a thin passivated layer of SiO 2 . There is currently much interest in its use as a semiconductor material in electronics, where its high thermal conductivity, high electric field breakdown strength and high maximum current density make it more promising than silicon for high-powered devices. SiC has a very low coefficient of thermal expansion of about 2.3 × 10 K near 300 K (for 4H and 6H SiC) and experiences no phase transitions in

29118-465: The formation of the Solar System . Silicon makes up 27.2% of the Earth's crust by weight, second only to oxygen at 45.5%, with which it always is associated in nature. Further fractionation took place in the formation of the Earth by planetary differentiation : Earth's core , which makes up 31.5% of the mass of the Earth, has approximate composition Fe 25 Ni 2 Co 0.1 S 3 ;

29329-779: The founding republics who signed the Treaty on the Creation of the USSR in December 1922. In 1924, during the national delimitation in Central Asia, Uzbekistan and Turkmenistan were formed from parts of Russia's Turkestan ASSR and two Soviet dependencies, the Khorezm and Bukharan PSPs . In 1929, Tajikistan was split off from the Uzbekistan SSR. With the constitution of 1936, the Transcaucasian SFSR

29540-410: The general party membership, as the key principle of the party organization was democratic centralism , demanding strict subordination to higher bodies, and elections went uncontested, endorsing the candidates proposed from above. The Communist Party maintained its dominance over the state mainly through its control over the system of appointments . All senior government officials and most deputies of

29751-525: The globe. The post-Stalin leadership, particularly under Nikita Khrushchev , initiated a de-Stalinization process, leading to a period of liberalization and relative openness known as the Khrushchev Thaw . However, the subsequent era under Leonid Brezhnev , referred to as the Era of Stagnation , was marked by economic decline, political corruption, and a rigid gerontocracy . Despite efforts to maintain

29962-438: The government. Extensive extrajudicial powers were given to the Soviet secret police agencies . In practice, the Soviet government significantly curbed the rule of law , civil liberties , protection of law and guarantees of property , which were considered as examples of "bourgeois morality" by Soviet law theorists such as Andrey Vyshinsky . The USSR and other countries in the Soviet Bloc had abstained from affirming

30173-431: The grip tape on skateboards . In 1982 an exceptionally strong composite of aluminium oxide and silicon carbide whiskers was discovered. Development of this laboratory-produced composite to a commercial product took only three years. In 1985, the first commercial cutting tools made from this alumina and silicon carbide whisker-reinforced composite were introduced into the market. In the 1980s and 1990s, silicon carbide

30384-522: The ground state, they are arranged in the electron configuration [Ne]3s 3p . Of these, four are valence electrons , occupying the 3s orbital and two of the 3p orbitals. Like the other members of its group, the lighter carbon and the heavier germanium , tin , and lead , it has the same number of valence electrons as valence orbitals: hence, it can complete its octet and obtain the stable noble gas configuration of argon by forming sp hybrid orbitals , forming tetrahedral SiX 4 derivatives where

30595-402: The highest bodies of the party and making the Supreme Soviet less dependent on them. The Congress of People's Deputies was established, the majority of whose members were directly elected in competitive elections held in March 1989, the first in Soviet history. The Congress now elected the Supreme Soviet, which became a full-time parliament, and much stronger than before. For the first time since

30806-596: The highest purity and are found closest to the resistor. The color changes to blue and black at greater distance from the resistor, and these darker crystals are less pure. Nitrogen and aluminium are common impurities, and they affect the electrical conductivity of SiC. Pure silicon carbide can be made by the Lely process , in which SiC powder is sublimed into high-temperature species of silicon, carbon, silicon dicarbide (SiC 2 ), and disilicon carbide (Si 2 C) in an argon gas ambient at 2,500 °C and redeposited into flake-like single crystals, sized up to 2 × 2 cm, at

31017-402: The implementation of socialist policies and the New Economic Policy (NEP), which allowed for market-oriented reforms. The rise of Joseph Stalin in the late 1920s ushered in an era of intense centralization and totalitarianism. Stalin's rule was characterized by the forced collectivization of agriculture , rapid industrialization , and the Great Purge , which eliminated perceived enemies of

31228-420: The incandescent method". The first use of SiC was as an abrasive. This was followed by electronic applications. In the beginning of the 20th century, silicon carbide was used as a detector in the first radios. In 1907 Henry Joseph Round produced the first LED by applying a voltage to a SiC crystal and observing yellow, green and orange emission at the cathode. The effect was later rediscovered by O.V. Losev in

31439-430: The increasing energy gap between the valence s and p orbitals as the group is descended, the divalent state grows in importance from carbon to lead, so that a few unstable divalent compounds are known for silicon; this lowering of the main oxidation state, in tandem with increasing atomic radii, results in an increase of metallic character down the group. Silicon already shows some incipient metallic behavior, particularly in

31650-417: The largest and most populous of which was the Russian SFSR . In practice, its government and economy were highly centralized . As a one-party state governed by the Communist Party of the Soviet Union , it was a flagship communist state . Its capital and largest city was Moscow . The Soviet Union's roots lay in the October Revolution of 1917. The new government, led by Vladimir Lenin , established

31861-402: The long-range tetrahedral network of bonds breaks up and the voids in that network are filled in, similar to water ice when hydrogen bonds are broken upon melting. It does not have any thermodynamically stable allotropes at standard pressure, but several other crystal structures are known at higher pressures. The general trend is one of increasing coordination number with pressure, culminating in

32072-425: The lower Ge–O bond strength compared to the Si–O bond strength results in the absence of "germanone" polymers that would be analogous to silicone polymers. Silicon is the eighth most abundant element in the universe, coming after hydrogen , helium , carbon , nitrogen , oxygen , iron , and neon . These abundances are not replicated well on Earth due to substantial separation of the elements taking place during

32283-449: The lowest unoccupied ones (the conduction band). The Fermi level is about halfway between the valence and conduction bands and is the energy at which a state is as likely to be occupied by an electron as not. Hence pure silicon is effectively an insulator at room temperature. However, doping silicon with a pnictogen such as phosphorus , arsenic , or antimony introduces one extra electron per dopant and these may then be excited into

32494-440: The majority of these have half-lives that are less than one-tenth of a second. Silicon has one known nuclear isomer , Si, with a half-life less than 210 nanoseconds. Si undergoes low-energy beta decay to P and then stable S . Si may be produced by the neutron activation of natural silicon and is thus useful for quantitative analysis; it can be easily detected by its characteristic beta decay to stable P , in which

32705-423: The market at that time. While rare on Earth, silicon carbide is remarkably common in space. It is a common form of stardust found around carbon-rich stars , and examples of this stardust have been found in pristine condition in primitive (unaltered) meteorites. The silicon carbide found in space and in meteorites is almost exclusively the beta-polymorph . Analysis of SiC grains found in the Murchison meteorite ,

32916-408: The material. Silicon carbide cladding does not experience this same mechanical degradation, but instead retains strength properties with increasing temperature. The composite consists of SiC fibers wrapped around a SiC inner layer and surrounded by an SiC outer layer. Problems have been reported with the ability to join the pieces of the SiC composite. As a gemstone used in jewelry , silicon carbide

33127-431: The method for making silicon carbide powder on February 28, 1893. Acheson also developed the electric batch furnace by which SiC is still made today and formed the Carborundum Company to manufacture bulk SiC, initially for use as an abrasive. In 1900 the company settled with the Electric Smelting and Aluminum Company when a judge's decision gave "priority broadly" to its founders "for reducing ores and other substances by

33338-435: The monocrystalline silicon: 75,000 to 150,000 metric tons per year. The market for the lesser grade is growing more quickly than for monocrystalline silicon. By 2013, polycrystalline silicon production, used mostly in solar cells, was projected to reach 200,000 metric tons per year, while monocrystalline semiconductor grade silicon was expected to remain less than 50,000 tons per year. Silicon quantum dots are created through

33549-438: The more expensive process of chemical vapor deposition (CVD) of silane, hydrogen and nitrogen. Homoepitaxial and heteroepitaxial SiC layers can be grown employing both gas and liquid phase approaches. To form complexly shaped SiC, preceramic polymers can be used as precursors which form the ceramic product through pyrolysis at temperatures in the range 1,000–1,100 °C. Precursor materials to obtain silicon carbide in such

33760-416: The most common Russian initialization is Союз ССР (transliteration: Soyuz SSR ) which essentially translates to Union of SSRs in English. In addition, the Russian short form name Советский Союз (transliteration: Sovyetsky Soyuz , which literally means Soviet Union ) is also commonly used, but only in its unabbreviated form. Since the start of the Great Patriotic War at the latest, abbreviating

33971-539: The natural minerals. Such use includes industrial construction with clays , silica sand , and stone . Silicates are used in Portland cement for mortar and stucco , and mixed with silica sand and gravel to make concrete for walkways, foundations, and roads. They are also used in whiteware ceramics such as porcelain , and in traditional silicate -based soda–lime glass and many other specialty glasses . Silicon compounds such as silicon carbide are used as abrasives and components of high-strength ceramics. Silicon

34182-417: The newly elected Supreme Soviet of the Russian SFSR , and communist hardliners. On 19–21 August 1991, a group of hardliners staged a coup attempt . The coup failed, and the State Council of the Soviet Union became the highest organ of state power 'in the period of transition'. Gorbachev resigned as General Secretary, only remaining President for the final months of the existence of the USSR. The judiciary

34393-400: The nominal head of state . The institutions at lower levels were overseen and at times supplanted by primary party organizations . However, in practice the degree of control the party was able to exercise over the state bureaucracy, particularly after the death of Stalin, was far from total, with the bureaucracy pursuing different interests that were at times in conflict with the party, nor

34604-422: The ocean: chemical weathering of continental rocks, river transport, dissolution of continental terrigenous silicates, and the reaction between submarine basalts and hydrothermal fluid which release dissolved silicon. All four of these fluxes are interconnected in the ocean's biogeochemical cycle as they all were initially formed from the weathering of Earth's crust. Approximately 300–900 megatonnes of Aeolian dust

34815-588: The oceans from the Sahara and Gobi Desert, respectively. Riverine transports are the major source of silicon influx into the ocean in coastal regions, while silicon deposition in the open ocean is greatly influenced by the settling of Aeolian dust. Silicon of 96–99% purity is made by carbothermically reducing quartzite or sand with highly pure coke . The reduction is carried out in an electric arc furnace , with an excess of SiO 2 used to stop silicon carbide (SiC) from accumulating: This reaction, known as carbothermal reduction of silicon dioxide, usually

35026-434: The oceans through groundwater and riverine transport. Large fluxes of groundwater input have an isotopic composition which is distinct from riverine silicon inputs. Isotopic variations in groundwater and riverine transports contribute to variations in oceanic Si values. Currently, there are substantial differences in the isotopic values of deep water in the world's ocean basins . Between the Atlantic and Pacific oceans, there

35237-552: The official Soviet system of importance (ground forces were second, Air Force fourth, and Navy fifth). The army had the greatest political influence. In 1989, there served two million soldiers divided between 150 motorized and 52 armored divisions. Until the early 1960s, the Soviet navy was a rather small military branch, but after the Caribbean crisis , under the leadership of Sergei Gorshkov , it expanded significantly. It became known for battlecruisers and submarines. In 1989, there served 500 000 men. The Soviet Air Force focused on

35448-420: The only legal party and the final policymaker in the country. At the top of the Communist Party was the Central Committee , elected at Party Congresses and Conferences. In turn, the Central Committee voted for a Politburo (called the Presidium between 1952 and 1966), Secretariat and the general secretary (First Secretary from 1953 to 1966), the de facto highest office in the Soviet Union. Depending on

35659-520: The other order until 1936 . In addition, in the regional languages of several republics, the word council or conciliar in the respective language was only quite late changed to an adaptation of the Russian soviet and never in others, e.g. Ukrainian SSR . СССР (in the Latin alphabet: SSSR ) is the abbreviation of the Russian-language cognate of USSR, as written in Cyrillic letters . The Soviets used this abbreviation so frequently that audiences worldwide became familiar with its meaning. After this,

35870-505: The oxide and isolate the element. After an attempt to isolate silicon in 1808, Sir Humphry Davy proposed the name "silicium" for silicon, from the Latin silex , silicis for flint, and adding the "-ium" ending because he believed it to be a metal. Most other languages use transliterated forms of Davy's name, sometimes adapted to local phonology (e.g. German Silizium , Turkish silisyum , Catalan silici , Armenian Սիլիցիում or Silitzioum ). A few others use instead

36081-494: The partition of Poland. In response, Britain and France declared war on Germany, marking the beginning of World War II . Up until his death in 1953, Joseph Stalin controlled all foreign relations of the Soviet Union during the interwar period . Despite the increasing build-up of Germany 's war machine and the outbreak of the Second Sino-Japanese War , the Soviet Union did not cooperate with any other nation, choosing to follow its own path. However, after Operation Barbarossa ,

36292-429: The party's highest body the Politburo . Operations were handled by the separate Ministry of Foreign Affairs . It was known as the People's Commissariat for Foreign Affairs (or Narkomindel), until 1946. The most influential spokesmen were Georgy Chicherin (1872–1936), Maxim Litvinov (1876–1951), Vyacheslav Molotov (1890–1986), Andrey Vyshinsky (1883–1954) and Andrei Gromyko (1909–1989). Intellectuals were based in

36503-446: The popular TO-247 and TO-220 packages, companies started even earlier to implement the bare chips into their power electronic modules . SiC SBD diodes found wide market spread being used in PFC circuits and IGBT power modules . Conferences such as the International Conference on Integrated Power Electronics Systems (CIPS) report regularly about the technological progress of SiC power devices. Major challenges for fully unleashing

36714-576: The product to a brown powder by repeatedly washing it. As a result, he is usually given credit for the element's discovery. The same year, Berzelius became the first to prepare silicon tetrachloride ; silicon tetrafluoride had already been prepared long before in 1771 by Carl Wilhelm Scheele by dissolving silica in hydrofluoric acid . In 1823 for the first time Jacob Berzelius discovered silicon tetrachloride (SiCl 4 ). In 1846 Von Ebelman's synthesized tetraethyl orthosilicate (Si(OC 2 H 5 ) 4 ). Silicon in its more common crystalline form

36925-450: The product, nor identify it as a new element. Silicon was given its present name in 1817 by Scottish chemist Thomas Thomson . He retained part of Davy's name but added "-on" because he believed that silicon was a nonmetal similar to boron and carbon . In 1824, Jöns Jacob Berzelius prepared amorphous silicon using approximately the same method as Gay-Lussac (reducing potassium fluorosilicate with molten potassium metal), but purifying

37136-724: The production of volatile organic compounds and phytohormones which play a significant role in plant defense mechanisms. In more advanced plants, the silica phytoliths (opal phytoliths) are rigid microscopic bodies occurring in the cell. Several horticultural crops are known to protect themselves against fungal plant pathogens with silica, to such a degree that fungicide application may fail unless accompanied by sufficient silicon nutrition. Silicaceous plant defense molecules activate some phytoalexins , meaning some of them are signalling substances producing acquired immunity . When deprived, some plants will substitute with increased production of other defensive substances. Life on Earth

37347-467: The pure element in the Earth's crust. It is widely distributed throughout space in cosmic dusts , planetoids , and planets as various forms of silicon dioxide (silica) or silicates . More than 90% of the Earth's crust is composed of silicate minerals , making silicon the second most abundant element in the Earth's crust (about 28% by mass), after oxygen . Most silicon is used commercially without being separated, often with very little processing of

37558-428: The quantum dot, allowing electrons to transfer between them, filling the holes and preventing recombination. Fluorescence resonance energy transfer occurs when a complex forms between the quantum dot and a quencher molecule. The complex will continue to absorb light but when the energy is converted to the ground state it does not release a photon, quenching the material. The third method uses different approach by measuring

37769-419: The reducing agent. The spongy pieces of silicon thus produced are melted and then grown to form cylindrical single crystals, before being purified by zone refining . Other routes use the thermal decomposition of silane or tetraiodosilane ( SiI 4 ). Another process used is the reduction of sodium hexafluorosilicate , a common waste product of the phosphate fertilizer industry, by metallic sodium : this

37980-437: The silicon carbide sold in the world, including moissanite jewels, is synthetic . Natural moissanite was first found in 1893 as a small component of the Canyon Diablo meteorite in Arizona by Ferdinand Henri Moissan , after whom the material was named in 1905. Moissan's discovery of naturally occurring SiC was initially disputed because his sample may have been contaminated by silicon carbide saw blades that were already on

38191-427: The state. The Soviet Union played a crucial role in the Allied victory in World War II , but at a tremendous human cost, with millions of Soviet citizens perishing in the conflict. The Soviet Union emerged as one of the world's two superpowers, leading the Eastern Bloc in opposition to the Western Bloc during the Cold War . This period saw the USSR engage in an arms race, the Space Race , and proxy wars around

38402-469: The struggle for dominance was expressed via indirect means such as psychological warfare , propaganda campaigns, espionage , far-reaching embargoes , rivalry at sports events and technological competitions such as the Space Race . Constitutionally, the USSR was a federation of constituent Union Republics, which were either unitary states, such as Ukraine or Byelorussia (SSRs), or federations, such as Russia or Transcaucasia (SFSRs), all four being

38613-484: The temperature range 5 K to 340 K that would cause discontinuities in the thermal expansion coefficient. Silicon carbide is a semiconductor , which can be doped n-type by nitrogen or phosphorus and p-type by beryllium , boron , aluminium , or gallium . Metallic conductivity has been achieved by heavy doping with boron, aluminium or nitrogen. Superconductivity has been detected in 3C-SiC:Al, 3C-SiC:B and 6H-SiC:B at similar temperatures ~1.5 K. A crucial difference

38824-535: The thermal processing of hydrogen silsesquioxane into nanocrystals ranging from a few nanometers to a few microns, displaying size dependent luminescent properties. The nanocrystals display large Stokes shifts converting photons in the ultraviolet range to photons in the visible or infrared, depending on the particle size, allowing for applications in quantum dot displays and luminescent solar concentrators due to their limited self absorption. A benefit of using silicon based quantum dots over cadmium or indium

39035-492: The truth". Human rights in the Soviet Union were severely limited. The Soviet Union was a totalitarian state from 1927 until 1953 and a one-party state until 1990. Freedom of speech was suppressed and dissent was punished. Independent political activities were not tolerated, whether these involved participation in free labour unions , private corporations , independent churches or opposition political parties . The freedom of movement within and especially outside

39246-403: The west further raised concerns. In the past, there were accidents involving submarines K-19 , K-8 , a K-129 , K-27 , K-219 and K-278 Komsomolets . There were three power hierarchies in the Soviet Union: the legislature represented by the Supreme Soviet of the Soviet Union , the government represented by the Council of Ministers , and the Communist Party of the Soviet Union (CPSU),

39457-406: The world's largest lakes; the Caspian Sea (shared with Iran ), and Lake Baikal , the world's largest (by volume) and deepest freshwater lake that is also an internal body of water in Russia. Neighbouring countries were aware of the high levels of pollution in the Soviet Union but after the dissolution of the Soviet Union it was discovered that its environmental problems were greater than what

39668-477: The world's use of free silicon. Silicon is an important constituent of transformer steel , modifying its resistivity and ferromagnetic properties. The properties of silicon may be used to modify alloys with metals other than iron. "Metallurgical grade" silicon is silicon of 95–99% purity. About 55% of the world consumption of metallurgical purity silicon goes for production of aluminium-silicon alloys ( silumin alloys) for aluminium part casts , mainly for use in

39879-452: Was a coastline . The country bordered Afghanistan , the People's Republic of China , Czechoslovakia , Finland , Hungary , Iran , Mongolia , North Korea , Norway , Poland , Romania , and Turkey from 1945 to 1991. The Bering Strait separated the USSR from the United States . The country's highest mountain was Communism Peak (now Ismoil Somoni Peak ) in Tajikistan , at 7,495 metres (24,590 ft). The USSR also included most of

40090-411: Was a silicon radio crystal detector, developed by American engineer Greenleaf Whittier Pickard in 1906. In 1940, Russell Ohl discovered the p–n junction and photovoltaic effects in silicon. In 1941, techniques for producing high-purity germanium and silicon crystals were developed for radar microwave detector crystals during World War II . In 1947, physicist William Shockley theorized

40301-408: Was also the industrial center of the Soviet Union. Historian Matthew White wrote that it was an open secret that the country's federal structure was 'window dressing' for Russian dominance. For that reason, the people of the USSR were usually called 'Russians', not 'Soviets', since 'everyone knew who really ran the show'. Under the Military Law of September 1925, the Soviet Armed Forces consisted of

40512-400: Was as a surge protection in lightning arresters in electric power systems. These devices must exhibit high resistance until the voltage across them reaches a certain threshold V T at which point their resistance must drop to a lower level and maintain this level until the applied voltage drops below V T flushing current into the ground. It was recognized early on that SiC had such

40723-434: Was brought under strict party control after Stalin's death. Under Yuri Andropov , the KGB engaged in the suppression of political dissent and maintained an extensive network of informers, reasserting itself as a political actor to some extent independent of the party-state structure, culminating in the anti-corruption campaign targeting high-ranking party officials in the late 1970s and early 1980s. The constitution , which

40934-419: Was carried out within the terms of the Soviet Civil Code. Some Soviet legal scholars even said that "criminal repression" may be applied in the absence of guilt. Martin Latsis , chief of Soviet Ukraine 's secret police explained: "Do not look in the file of incriminating evidence to see whether or not the accused rose up against the Soviets with arms or words. Ask him instead to which class he belongs, what

41145-404: Was colloquially, but incorrectly, referred to as Russia . The history of the Soviet Union began with the ideals of the Bolshevik Revolution and ended in dissolution amidst economic collapse and political disintegration. Established in 1922 following the Russian Civil War , the Soviet Union quickly became a one-party state under the Communist Party . Its early years under Lenin were marked by

41356-404: Was dissolved, resulting in its constituent republics of Armenia , Georgia and Azerbaijan being elevated to Union Republics, while Kazakhstan and Kirghizia were split off from the Russian SFSR, resulting in the same status. In August 1940, Moldavia was formed from parts of Ukraine and Soviet-occupied Bessarabia , and Ukrainian SSR. Estonia , Latvia and Lithuania were also annexed by

41567-424: Was no large-scale fighting directly between the two superpowers , but they each supported major regional conflicts known as proxy wars . The conflict was based around the ideological and geopolitical struggle for global influence by these two superpowers, following their temporary alliance and victory against Nazi Germany in 1945. Aside from the nuclear arsenal development and conventional military deployment,

41778-450: Was not independent of the other branches of government. The Supreme Court supervised the lower courts ( People's Court ) and applied the law as established by the constitution or as interpreted by the Supreme Soviet. The Constitutional Oversight Committee reviewed the constitutionality of laws and acts. The Soviet Union used the inquisitorial system of Roman law , where the judge, procurator , and defence attorney collaborate to "establish

41989-464: Was not prepared until 31 years later, by Deville . By electrolyzing a mixture of sodium chloride and aluminium chloride containing approximately 10% silicon, he was able to obtain a slightly impure allotrope of silicon in 1854. Later, more cost-effective methods have been developed to isolate several allotrope forms, the most recent being silicene in 2010. Meanwhile, research on the chemistry of silicon continued; Friedrich Wöhler discovered

42200-443: Was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its oxides form a family of anions known as silicates . Its melting and boiling points of 1414 °C and 3265 °C, respectively, are the second highest among all the metalloids and nonmetals, being surpassed only by boron . Silicon is the eighth most common element in the universe by mass, but very rarely occurs as

42411-482: Was originally intended to eliminate the need for the spark gap in lightning arresters. Gapped SiC arresters were used for lightning-protection and sold under the GE and Westinghouse brand names, among others. The gapped SiC arrester has been largely displaced by no-gap varistors that use columns of zinc oxide pellets. Silicon carbide was the first commercially important semiconductor material. A crystal radio "carborundum" (synthetic silicon carbide) detector diode

42622-523: Was patented by Henry Harrison Chase Dunwoody in 1906. It found much early use in shipboard receivers. In 1993, the silicon carbide was considered a semiconductor in both research and early mass production providing advantages for fast, high-temperature and/or high-voltage devices. The first devices available were Schottky diodes , followed by junction-gate FETs and MOSFETs for high-power switching. Bipolar transistors and thyristors were described. A major problem for SiC commercialization has been

42833-433: Was promulgated in 1924 , 1936 and 1977 , did not limit state power. No formal separation of powers existed between the Party, Supreme Soviet and Council of Ministers that represented executive and legislative branches of the government. The system was governed less by statute than by informal conventions, and no settled mechanism of leadership succession existed. Bitter and at times deadly power struggles took place in

43044-477: Was repeatedly postponed. Formal recognition came when the new Labour Party came to power in 1924. All the other countries followed suit in opening trade relations. Henry Ford opened large-scale business relations with the Soviets in the late 1920s, hoping that it would lead to long-term peace. Finally, in 1933, the United States officially recognized the USSR, a decision backed by the public opinion and especially by US business interests that expected an opening of

43255-442: Was studied in several research programs for high-temperature gas turbines in Europe , Japan and the United States . The components were intended to replace nickel superalloy turbine blades or nozzle vanes. However, none of these projects resulted in a production quantity, mainly because of its low impact resistance and its low fracture toughness . Like other hard ceramics (namely alumina and boron carbide ), silicon carbide

43466-552: Was synthesised by Charles Friedel and James Crafts in 1863, but detailed characterisation of organosilicon chemistry was only done in the early 20th century by Frederic Kipping . Starting in the 1920s, the work of William Lawrence Bragg on X-ray crystallography elucidated the compositions of the silicates, which had previously been known from analytical chemistry but had not yet been understood, together with Linus Pauling 's development of crystal chemistry and Victor Goldschmidt 's development of geochemistry . The middle of

43677-482: Was that "the Constitution was written not for you, but for American Negroes, so that they know how happy the lives of Soviet citizens are". Crime was determined not as the infraction of law, instead, it was determined as any action which could threaten the Soviet state and society. For example, a desire to make a profit could be interpreted as a counter-revolutionary activity punishable by death. The liquidation and deportation of millions of peasants in 1928–31

43888-506: Was the Russian responsibility to assist them. The Comintern was the weapon of choice. A few revolutions did break out, but they were quickly suppressed (the longest lasting one was in Hungary)—the Hungarian Soviet Republic —lasted only from 21 March 1919 to 1 August 1919. The Russian Bolsheviks were in no position to give any help. By 1921, Lenin, Trotsky, and Stalin realized that capitalism had stabilized itself in Europe and there would not be any widespread revolutions anytime soon. It became

44099-404: Was the first major accident at a civilian nuclear power plant . Unparalleled in the world, it resulted in a large number of radioactive isotopes being released into the atmosphere. Radioactive doses were scattered relatively far. Although long-term effects of the accident were unknown, 4,000 new cases of thyroid cancer which resulted from the accident's contamination were reported at the time of

44310-431: Was the party itself monolithic from top to bottom, although factions were officially banned . The Supreme Soviet (successor of the Congress of Soviets ) was nominally the highest state body for most of the Soviet history, at first acting as a rubber stamp institution, approving and implementing all decisions made by the party. However, its powers and functions were extended in the late 1950s, 1960s and 1970s, including

44521-457: Was then the world's brightest LED. By 1970 it had been usurped by brighter red LEDs, but yellow LEDs made from 3C-SiC continued to be manufactured in the Soviet Union in the 1970s and blue LEDs (6H-SiC) worldwide in the 1980s. Carbide LED production soon stopped when a different material, gallium nitride , showed 10–100 times brighter emission. This difference in efficiency is due to the unfavorable indirect bandgap of SiC, whereas GaN has

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