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Rhodium
Rhodium is a chemical element with the symbol Rh and atomic number 45. It is a very rare, silvery-white, hard, corrosion-resistant transition metal. It is a noble metal and a member of the platinum group. It has only one naturally occurring isotope: 103Rh. Naturally occurring rhodium is usually found as a free metal or as an alloy with similar metals and rarely as a chemical compound in minerals such as bowieite and rhodplumsite. It is one of the rarest and most valuable precious metals. Rhodium is found in platinum or nickel ores with the other members of the platinum group metals. It was discovered in 1803 by William Hyde Wollaston in one such ore, and named for the rose color of one of its chlorine compounds. The element's major use (consuming about 80% of world rhodium production) is as one of the catalysts in the three-way catalytic converters in automobiles. Because rhodium metal is inert against corrosion and most aggressive chemicals, and because of its rarity, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rh Blood Group System
The Rh blood group system is a human blood group system. It contains proteins on the surface of red blood cells. After the ABO blood group system, it is the most likely to be involved in transfusion reactions. The Rh blood group system consists of 49 defined blood group antigens, among which the five antigens D, C, c, E, and e are the most important. There is no d antigen. Rh(D) status of an individual is normally described with a ''positive'' (+) or ''negative'' (−) suffix after the ABO type (e.g., someone who is A+ has the A antigen and Rh(D) antigen, whereas someone who is A− has the A antigen but lacks the Rh(D) antigen). The terms ''Rh factor'', ''Rh positive'', and ''Rh negative'' refer to the Rh(D) antigen only. Antibodies to Rh antigens can be involved in hemolytic transfusion reactions and antibodies to the Rh(D) and Rh antigens confer significant risk of hemolytic disease of the fetus and newborn. Nomenclature The Rh blood group system has two sets of nomenclatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Republika Hrvatska
, image_flag = Flag of Croatia.svg , image_coat = Coat of arms of Croatia.svg , anthem = " Lijepa naša domovino"("Our Beautiful Homeland") , image_map = , map_caption = , capital = Zagreb , coordinates = , largest_city = capital , official_languages = Croatian , languages_type = Writing system , languages = Latin , ethnic_groups = , ethnic_groups_year = 2021 , religion = , religion_year = 2021 , demonym = , government_type = Unitary parliamentary republic , leader_title1 = President , leader_name1 = Zoran Milanović , leader_title2 = Prime Minister , leader_name2 = Andrej Plenković , leader_title3 = Speaker of Parliament , leader_name3 = Gordan Jandroković , legislature = Sabor , sovereignty_type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rh (digraph)
This is a list of digraphs used in various Latin alphabets. Capitalisation involves only the first letter (''ch'' becomes ''Ch'') unless otherwise stated (''ij'' becomes ''IJ''). Letters with diacritics are arranged in alphabetic order according to their base: is alphabetised with , not at the end of the alphabet, as it would be in Danish, Norwegian and Swedish. Substantially-modified letters, such as (a variant of ) and (based on ), are placed at the end. Apostrophe (capital ) is used in Bari for . (capital ) is used in Bari for . is used in the Wu MiniDict Romanisation for when it appears in a dark or ''yin'' tone. It is also often written as . is used in the Wu MiniDict Romanisation for dark is used in the Wu MiniDict Romanisation for dark is used in the Wu MiniDict Romanisation for dark (capital ) is used in Bari and Hausa (in Nigeria) for , but in Niger, Hausa is replaced with . A is used in Taa, where it represents the glottalized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riemann Hypothesis
In mathematics, the Riemann hypothesis is the conjecture that the Riemann zeta function has its zeros only at the negative even integers and complex numbers with real part . Many consider it to be the most important unsolved problem in pure mathematics. It is of great interest in number theory because it implies results about the distribution of prime numbers. It was proposed by , after whom it is named. The Riemann hypothesis and some of its generalizations, along with Goldbach's conjecture and the twin prime conjecture, make up Hilbert's eighth problem in David Hilbert's list of twenty-three unsolved problems; it is also one of the Clay Mathematics Institute's Millennium Prize Problems, which offers a million dollars to anyone who solves any of them. The name is also used for some closely related analogues, such as the Riemann hypothesis for curves over finite fields. The Riemann zeta function ζ(''s'') is a function whose argument ''s'' may be any complex numbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Humidity
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depends on the temperature and pressure of the system of interest. The same amount of water vapor results in higher relative humidity in cool air than warm air. A related parameter is the dew point. The amount of water vapor needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of air decreases it will eventually reach the saturation point without adding or losing water mass. The amount of water vapor contained within a parcel of air can vary significantly. For example, a parcel of air near saturation may contain 28 g of water per cubic metre of air at , but only 8 g of water per cubic metre of air at . Three primary measurements of humidity are widely employed: absolute, relative, and specific. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Hat
Red Hat, Inc. is an American software company that provides open source software products to enterprises. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina, with other offices worldwide. Red Hat has become associated to a large extent with its enterprise operating system Red Hat Enterprise Linux. With the acquisition of open-source enterprise middleware vendor JBoss, Red Hat also offers Red Hat Virtualization (RHV), an enterprise virtualization product. Red Hat provides storage, operating system platforms, middleware, applications, management products, and support, training, and consulting services. Red Hat creates, maintains, and contributes to many free software projects. It has acquired several proprietary software product codebases through corporate mergers and acquisitions and has released such software under open source licenses. , Red Hat is the second largest corporate contributor to the Linux kernel version 4.14 after Intel. On Oc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RH (company)
RH (formerly Restoration Hardware) is an upscale American home-furnishings company headquartered in Corte Madera, California. The company sells its merchandise through its retail stores, catalog, and online. As of August 2018, the company operated a total of 70 galleries, 18 full-line design galleries, and 6 baby-and-child galleries. The company also has 36 outlet stores in the United States and Canada. History Stephen Gordon founded Restoration Hardware in Eureka, California, in 1979 while restoring a Victorian home and finding affordable, high-quality hardware and fixtures unavailable. The company expanded slowly in Northern California and Boston before raising outside capital from Cardinal Investments which allowed it to accelerate its expansion. The company had 47 stores when it went public in 1998, ending the year at over 65 stores. It then expanded to over 100 stores in 31 states, with $369.5 million in net sales by 2001. In 2001, Gary Friedman joined the company from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Republic Express Airlines
Republic Express Airlines (RPX Airlines) is a cargo airline based in Jakarta, Indonesia. It operates domestic and regional cargo services.Flight International 12–18 April 2005 Republic Express Airlines is listed in category 2 by Indonesian Civil Aviation Authority for airline safety quality. History The airline was established in 2001 and started operations on 17 October 2001. It is wholly owned by the RPX Group. Since 1985 RPX has been the licensee in Indonesia for Federal Express. The European Union's ban on the airline operations have been lifted. Destinations The airline flies to Batam, Jakarta, Kuala Lumpur, Surabaya, Balikpapan, Makassar, Pekanbaru and Surakarta. Fleet As of December 2012, the Republic Express Airlines fleet includes:Flight International ''Flight International'' is a monthly magazine focused on aerospace. Published in the United Kingdom and founded in 1909 as "A Journal devoted to the Interests, Practice, and Progress of Aerial Locomotion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Releasing Hormone
Releasing hormones and inhibiting hormones are hormones whose main purpose is to control the release of other hormones, either by stimulating or inhibiting their release. They are also called liberins () and statins () (respectively), or releasing factors and inhibiting factors. The principal examples are hypothalamic-pituitary hormones that can be classified from several viewpoints: they are hypothalamic hormones (originating in the hypothalamus), they are hypophysiotropic hormones (affecting the hypophysis, that is, the pituitary gland), and they are tropic hormones (having other endocrine glands as their target). For example, thyrotropin-releasing hormone (TRH) is released from the hypothalamus in response to low levels of secretion of thyroid-stimulating hormone (TSH) from the pituitary gland. The TSH in turn is under feedback control by the thyroid hormones T4 and T3. When the level of TSH is too high, they feed back on the brain to shut down the secretion of TRH. Syntheti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rydberg Constant
In spectroscopy, the Rydberg constant, symbol R_\infty for heavy atoms or R_\text for hydrogen, named after the Swedish physicist Johannes Rydberg, is a physical constant relating to the electromagnetic spectra of an atom. The constant first arose as an empirical fitting parameter in the Rydberg formula for the hydrogen spectral series, but Niels Bohr later showed that its value could be calculated from more fundamental constants via his Bohr model. Before the redefinition of the SI base units in , R_\infty and the electron spin ''g''-factor were the most accurately measured physical constants. The constant is expressed for either hydrogen as R_\text, or at the limit of infinite nuclear mass as R_\infty. In either case, the constant is used to express the limiting value of the highest wavenumber (inverse wavelength) of any photon that can be emitted from an atom, or, alternatively, the wavenumber of the lowest-energy photon capable of ionizing an atom from its ground state ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RH Postcode Area
The RH postcode area, also known as the Redhill postcode area,Royal Mail, ''Address Management Guide'', (2004) is a group of twenty postcode districts in South East England, within seventeen post towns. These cover east Surrey (including Redhill, Reigate, Betchworth, Dorking, Lingfield, Horley, Oxted and Godstone) and northeastern West Sussex (including Crawley, Gatwick, Haywards Heath, Billingshurst, East Grinstead, Burgess Hill, Horsham and Pulborough) plus small parts of northwestern East Sussex (including Forest Row). The main sorting office is in Crawley (Gatwick Mail Centre), and the area served includes parts of the Surrey districts of Guildford, Mole Valley, Reigate and Banstead and Tandridge, as well as most of the West Sussex districts of Crawley, Horsham and Mid Sussex, and small parts of the East Sussex districts of Lewes and Wealden. __TOC__ Coverage The approximate coverage of the postcode districts: , - ! RH1 , REDHILL , Redhill, Merstham, Earlsw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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