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Yttralox
Yttralox is a Transparent ceramics, transparent ceramic consisting of yttria (Y2O3) containing approximately 10% thorium dioxide (ThO2). It was one of the first transparent ceramics produced, and was invented in 1966 by Richard C. Anderson at the General Electric Research Laboratory while sintering mixtures of Rare-earth element, rare earth minerals. Properties Yttralox is a solid solution of thorium dioxide in yttria. The thorium dioxide additive affects the growth of Crystallite, grains during Sintering#Densification, vitrification and grain growth, densification, leading to improved optical transparency. Uncontrolled grain growth allows a few grains to grow larger than the others, trapping pores inside them. The additive increases the grain boundary hardness more than the internal grain hardness. This causes porosity to remain on grain boundaries rather than becoming trapped inside grains, allowing them to be eliminated later in the sintering process. This greatly impr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transparent Ceramics
Many Ceramics, ceramic materials, both glassy and crystalline, have found use as optically Transparency and translucency, transparent materials in various forms from bulk solid-state components to high surface area forms such as thin films, coatings, and fibers. Such devices have found widespread use for various applications in the electro-optical field including: fiber optics, optical fibers for guided lightwave transmission, optical switches, laser amplifiers and Lens (optics), lenses, hosts for solid-state lasers and optical window materials for gas lasers, and Infrared homing, infrared (IR) heat seeking devices for missile guidance systems and night vision devices, IR night vision. Harris, D.C. (2009) "Materials for Infrared Windows and Domes: Properties and Performance", SPIE PRESS Monograph, Vol. PM70 (Int. Society of Optical Engineers, Bellingham WA) In commercial and general knowledge domains, it is commonly accepted that transparent ceramics or ceramic glass are varieties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yttria
Yttrium oxide, also known as yttria, is Y2 O3. It is an air-stable, white solid substance. The thermal conductivity of yttrium oxide is 27 W/(m·K). Applications Phosphors Yttrium oxide is widely used to make Eu:YVO4 and Eu:Y2O3 phosphors that give the red color in color TV picture tubes. Yttria lasers Y2O3 is a prospective solid-state laser material. In particular, lasers with ytterbium as dopant allow the efficient operation both in continuous operation and in pulsed regimes. At high concentration of excitations (of order of 1%) and poor cooling, the quenching of emission at laser frequency and avalanche broadband emission takes place. (Yttria-based lasers are not to be confused with YAG lasers using yttrium aluminium garnet, a widely used crystal host for rare earth laser dopants). Gas lighting The original use of the mineral yttria and the purpose of its extraction from mineral sources was as part of the process of making gas mantles and other products for turning the fla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Doppler Velocimetry
Laser Doppler velocimetry, also known as laser Doppler anemometry, is the technique of using the Doppler shift in a laser beam to measure the velocity in transparent or semi-transparent fluid flows or the linear or vibratory motion of opaque, reflecting surfaces. The measurement with laser Doppler anemometry is absolute and linear with velocity and requires no pre-calibration. Technology origin The development of the helium–neon laser (He-Ne) in 1962 at the Bell Telephone Laboratories provided the optics community with a continuous wave electromagnetic radiation source that was highly concentrated at a wavelength of 632.8 nanometers (nm) in the red portion of the visible spectrum. It was discovered that fluid flow measurements could be made using the Doppler effect on a He-Ne beam scattered by small polystyrene spheres in the fluid. At the Research Laboratories of Brown Engineering Company (later Teledyne Brown Engineering), this phenomenon was used to develop the first laser D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceramic Materials
A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, and brick. The earliest ceramics made by humans were fired clay bricks used for building house walls and other structures. Other pottery objects such as pots, vessels, vases and figurines were made from clay, either by itself or mixed with other materials like silica, hardened by sintering in fire. Later, ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through the use of glassy, amorphous ceramic coatings on top of the crystalline ceramic substrates. Ceramics now include domestic, industrial, and building products, as well as a wide range of materials developed for use in advanced ceramic engineering, such as semiconductors. The word ''ceramic'' comes from the Ancient Greek word (), meaning "of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Force Systems Command
The Air Force Systems Command (AFSC) is an inactive United States Air Force Major Command. It was established in April 1951, being split off from Air Materiel Command. The mission of AFSC was Research and Development for new weapons systems. AFSC took on engineering functions which formerly resided in the Air Materiel Command (AMC), the Army Air Forces Technical Service Command, and the Air Technical Service Command (ATSC) as a separate research and development command in 1950. It incorporated Air Proving Ground Command in 1957. On 1 July 1992, AFSC and Air Force Logistics Command were merged to form the Air Force Materiel Command, located at Wright-Patterson Air Force Base, Ohio. In the reorganization of 1961, Air Force Systems Command acquired the materiel procurement function from Air Force Logistics Command. It was re-integrated with Air Force Logistics Command in 1992. History The World War II, Second World War had shown the destructiveness of aerial attack and made Genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hafnium Dioxide
Hafnium is a chemical element; it has symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1922, by Dirk Coster and George de Hevesy. Hafnium is named after , the Latin name for Copenhagen, where it was discovered. Hafnium is used in filaments and electrodes. Some semiconductor fabrication processes use its oxide for integrated circuits at 45 nanometers and smaller feature lengths. Some superalloys used for special applications contain hafnium in combination with niobium, titanium, or tungsten. Hafnium's large neutron capture cross section makes it a good material for neutron absorption in control rods in nuclear power plants, but at the same time requires that it be removed from the neutron-transparent corrosion-resistant zirconium alloys used in nuclear reactors. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group 4 Element
Group 4 is the second group of transition metals in the periodic table. It contains only the four elements titanium (Ti), zirconium (Zr), hafnium (Hf), and rutherfordium (Rf). The group is also called the titanium group or titanium family after its lightest member. As is typical for early transition metals, zirconium and hafnium have only the group oxidation state of +4 as a major one, and are quite electropositive and have a less rich coordination chemistry. Due to the effects of the lanthanide contraction, they are very similar in properties. Titanium is somewhat distinct due to its smaller size: it has a well-defined +3 state as well (although +4 is more stable). All the group 4 elements are hard. Their inherent reactivity is completely masked due to the formation of a dense oxide layer that protects them from corrosion, as well as attack by many acids and alkalis. The first three of them occur naturally. Rutherfordium is strongly radioactive: it does not occur naturally and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zirconium Dioxide
Zirconium dioxide (), sometimes known as zirconia (not to be confused with zirconium silicate or zircon), is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite. A dopant stabilized cubic structured zirconia, cubic zirconia, is synthesized in various colours for use as a gemstone and a diamond simulant. Production, chemical properties, occurrence Zirconia is produced by calcining zirconium compounds, exploiting its high thermostability.Ralph Nielsen "Zirconium and Zirconium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. Structure Three phases are known: monoclinic below 1170 °C, tetragonal between 1170 °C and 2370 °C, and cubic above 2370 °C. The trend is for higher symmetry at higher temperatures, as is usually the case. A small percentage of the oxides of calcium or yttrium stabilize in the cubic phase. The very r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard C Anderson Holding Up Yttralox
Richard is a male given name. It originates, via Old French, from Old Frankish and is a compound of the words descending from Proto-Germanic language">Proto-Germanic ''*rīk-'' 'ruler, leader, king' and ''*hardu-'' 'strong, brave, hardy', and it therefore means 'strong in rule'. Nicknames include "Richie", " Dick", "Dickon", " Dickie", "Rich", "Rick", "Rico (name), Rico", " Ricky", and more. Richard is a common English (the name was introduced into England by the Normans), German and French male name. It's also used in many more languages, particularly Germanic, such as Norwegian, Danish, Swedish, Icelandic, and Dutch, as well as other languages including Irish, Scottish, Welsh and Finnish. Richard is cognate with variants of the name in other European languages, such as the Swedish "Rickard", the Portuguese and Spanish "Ricardo" and the Italian "Riccardo" (see comprehensive variant list below). People named Richard Multiple people with the same name * Richard Andersen (d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raytheon
Raytheon is a business unit of RTX Corporation and is a major U.S. defense contractor and industrial corporation with manufacturing concentrations in weapons and military and commercial electronics. Founded in 1922, it merged in 2020 with United Technologies Corporation to form Raytheon Technologies, which changed its name to RTX Corporation in July 2023. Raytheon was established in 1922, reincorporated in 1928, and adopted the Raytheon Company name in 1959. More than 90% of Raytheon's revenues were obtained from military contracts and, as of 2012, it was the fifth-largest military contractor in the world. , it was the third-largest defense contractor in the United States by defense revenue. It was the world's largest producer of guided missiles, and was involved in corporate and special-mission aircraft until early 2007. In 2018, the company had around 67,000 employees worldwide and annual revenues of about US$25.35 billion. Over the years, Raytheon shifted its headquarters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lanthanum Oxide
Lanthanum(III) oxide, also known as lanthana, chemical formula , is an inorganic compound containing the rare earth element lanthanum and oxygen. It is used in some ferroelectric materials, as a component of optical materials, and is a feedstock for certain catalysts, among other uses. Properties Lanthanum oxide is a white solid that is insoluble in water, but dissolves in acidic solutions. absorbs moisture from air, converting to lanthanum hydroxide. Lanthanum oxide has p-type semiconducting properties and a band gap of approximately 5.8 eV. Its average room temperature resistivity is 10 kΩ·cm, which decreases with an increase in temperature. has the lowest lattice energy of the rare earth oxides, with very high dielectric constant ε = 27. Structure At low temperatures, has an A- hexagonal crystal structure. The metal atoms are surrounded by a 7 coordinate group of atoms, the oxygen ions are in an octahedral shape around the metal atom and there is one oxygen ion above ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
