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QR 4012 (Snydertown Road)
QR may refer to: Arts and entertainment * Nippon Cultural Broadcasting (from call sign JOQR), a Tokyo radio station * Queen's Radio, a student radio station at Queen's University Belfast * Quiet Riot, an American rock band Businesses * Qatar Airways (IATA code) * Queensland Rail, a company responsible for the railway system in Queensland, Australia * Quintana Roo (company), a triathlon-specific wetsuit and bicycle company Places * Quintana Roo, a state of Mexico * Karakalpakstan (Qoraqalpog'iston Respublikasi), Uzbekistan (ISO 3166-2 subcode UZ-QR) Science and technology * QR code (Quick Response code), a two-dimensional code * ATCvet code QR ''Respiratory system'', a section of the Anatomical Therapeutic Chemical Classification System for veterinary medicinal products * DICOM Q/R, DICOM Query / Retrieve * Nissan QR engine Mathematics * QR decomposition, a decomposition of a matrix * QR algorithm, an eigenvalue algorithm using QR decomposition * Quadratic reciproci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Queensrÿche
Queensrÿche is an American heavy metal band. It formed in 1982 in Bellevue, Washington, out of the local band the Mob. The band has released 16 studio albums, one EP, and several DVDs, and continues to tour and record. The original lineup consisted of guitarists Michael Wilton and Chris DeGarmo, drummer Scott Rockenfield, bassist Eddie Jackson, and lead vocalist Geoff Tate. Queensrÿche has sold over 20 million albums worldwide, including over six million albums in the United States. They are considered one of the leaders of the progressive metal scene of the mid-to-late 1980s, and often referred to as one of the "Big Three" of the genre, along with Dream Theater and Fates Warning. The band received worldwide acclaim after the release of their 1988 album '' Operation: Mindcrime'', which is often considered one of the greatest heavy metal concept albums of all time. Their next album, ''Empire'' (1990), was also very successful and included the hit single "Silent Lucidity" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QR Code
A QR code (an initialism for quick response code) is a type of matrix barcode (or two-dimensional barcode) invented in 1994 by the Japanese company Denso Wave. A barcode is a machine-readable optical label that can contain information about the item to which it is attached. In practice, QR codes often contain data for a locator, identifier, or tracker that points to a website or application. QR codes use four standardized encoding modes (numeric, alphanumeric, byte/binary, and kanji) to store data efficiently; extensions may also be used. The quick response system became popular outside the automotive industry due to its fast readability and greater storage capacity compared to standard UPC barcodes. Applications include product tracking, item identification, time tracking, document management, and general marketing. A QR code consists of black squares arranged in a square grid on a white background, including some fiducial markers, which can be read by an imaging device suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Quotient
In chemical thermodynamics, the reaction quotient (''Q''r or just ''Q'') is a dimensionless quantity that provides a measurement of the relative amounts of products and reactants present in a reaction mixture for a reaction with well-defined overall stoichiometry, at a particular point in time. Mathematically, it is defined as the ratio of the activities (or molar concentrations) of the product species over those of the reactant species involved in the chemical reaction, taking stoichiometric coefficients of the reaction into account as exponents of the concentrations. In equilibrium, the reaction quotient is constant over time and is equal to the equilibrium constant. A general chemical reaction in which ''α'' moles of a reactant A and ''β'' moles of a reactant B react to give ''ρ'' moles of a product R and ''σ'' moles of a product S can be written as :\it \alpha\,\rm A + \it \beta\,\rm B \it \rho\,\rm R + \it \sigma\,\rm S. The reaction is written as an equilibrium even t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quasireversibility
In queueing theory, a discipline within the mathematical theory of probability, quasireversibility (sometimes QR) is a property of some queues. The concept was first identified by Richard R. Muntz and further developed by Frank Kelly. Quasireversibility differs from reversibility in that a stronger condition is imposed on arrival rates and a weaker condition is applied on probability fluxes. For example, an M/M/1 queue with state-dependent arrival rates and state-dependent service times is reversible, but not quasireversible. A network of queues, such that each individual queue when considered in isolation is quasireversible, always has a product form stationary distribution. Quasireversibility had been conjectured to be a necessary condition for a product form solution in a queueing network, but this was shown not to be the case. Chao et al. exhibited a product form network where quasireversibility was not satisfied. Definition A queue with stationary distribution \pi is quasire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadratic Reciprocity
In number theory, the law of quadratic reciprocity is a theorem about modular arithmetic that gives conditions for the solvability of quadratic equations modulo prime numbers. Due to its subtlety, it has many formulations, but the most standard statement is: This law, together with its #q_=_±1_and_the_first_supplement, supplements, allows the easy calculation of any Legendre symbol, making it possible to determine whether there is an integer solution for any quadratic equation of the form x^2\equiv a \bmod p for an odd prime p; that is, to determine the "perfect squares" modulo p. However, this is a constructivism (mathematics), non-constructive result: it gives no help at all for finding a ''specific'' solution; for this, other methods are required. For example, in the case p\equiv 3 \bmod 4 using Euler's criterion one can give an explicit formula for the "square roots" modulo p of a quadratic residue a, namely, :\pm a^ indeed, :\left (\pm a^ \right )^2=a^=a\cdot a^\equiv a\ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QR Algorithm
In numerical linear algebra, the QR algorithm or QR iteration is an eigenvalue algorithm: that is, a procedure to calculate the eigenvalues and eigenvectors of a matrix. The QR algorithm was developed in the late 1950s by John G. F. Francis and by Vera N. Kublanovskaya, working independently. The basic idea is to perform a QR decomposition, writing the matrix as a product of an orthogonal matrix and an upper triangular matrix, multiply the factors in the reverse order, and iterate. The practical QR algorithm Formally, let ''A'' be a real matrix of which we want to compute the eigenvalues, and let ''A''0:=''A''. At the ''k''-th step (starting with ''k'' = 0), we compute the QR decomposition ''A''''k''=''Q''''k''''R''''k'' where ''Q''''k'' is an orthogonal matrix (i.e., ''Q''''T'' = ''Q''−1) and ''R''''k'' is an upper triangular matrix. We then form ''A''''k''+1 = ''R''''k''''Q''''k''. Note that : A_ = R_k Q_k = Q_k^ Q_k R_k Q_k = Q_k^ A_k Q_k = Q_k^ A_k Q_k, so all the ''A''''k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QR Decomposition
In linear algebra, a QR decomposition, also known as a QR factorization or QU factorization, is a decomposition of a matrix ''A'' into a product ''A'' = ''QR'' of an orthogonal matrix ''Q'' and an upper triangular matrix ''R''. QR decomposition is often used to solve the linear least squares problem and is the basis for a particular eigenvalue algorithm, the QR algorithm. Cases and definitions Square matrix Any real square matrix ''A'' may be decomposed as : A = QR, where ''Q'' is an orthogonal matrix (its columns are orthogonal unit vectors meaning and ''R'' is an upper triangular matrix (also called right triangular matrix). If ''A'' is invertible, then the factorization is unique if we require the diagonal elements of ''R'' to be positive. If instead ''A'' is a complex square matrix, then there is a decomposition ''A'' = ''QR'' where ''Q'' is a unitary matrix (so If ''A'' has ''n'' linearly independent columns, then the first ''n'' columns of ''Q'' form an ortho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nissan QR Engine
The QR family of inline-four piston engines by Nissan were introduced in 2000 and range from in displacement. These motors are aluminum, dual overhead camshaft (DOHC), four-valve designs with variable valve timing and optional direct injection. The engine shares much of its architecture with the YD diesel engine. QR20DE QR20DE The QR20DE produces at 6000 rpm and at 4000 rpm. The bore and stroke is and a compression ratio of 9.9:1. The QR20DE was replaced with the MR20DE engine in most applications in early 2005. Vehicle applications: * 2001-2007 Nissan X-Trail T30, * 2001-2007 Nissan Primera P12 * 2002–present Nissan Serena C24, * 2003-2008 Nissan Teana J31, * 2001-2005 Nissan Wingroad Y11 * 2002-2005 Nissan Avenir W11 * 2001-2004 Nissan Prairie M12 * 2007-2020 Nissan Atlas F24 QR20DD The QR20DD is similar to the QR20DE but features NEO direct injection to improve fuel economy and to reduce emissionIt produces at 6000 rpm and at 4400 rpm. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DICOM
Digital Imaging and Communications in Medicine (DICOM) is the standard for the communication and management of medical imaging information and related data. DICOM is most commonly used for storing and transmitting medical images enabling the integration of medical imaging devices such as scanners, servers, workstations, printers, network hardware, and picture archiving and communication systems (PACS) from multiple manufacturers. It has been widely adopted by hospitals and is making inroads into smaller applications such as dentists' and doctors' offices. DICOM files can be exchanged between two entities that are capable of receiving image and patient data in DICOM format. The different devices come with DICOM Conformance Statements which state which DICOM classes they support. The standard includes a file format definition and a network communications protocol that uses TCP/IP to communicate between systems. The National Electrical Manufacturers Association (NEMA) holds the cop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karakalpakstan
Karakalpakstan, / officially the Republic of Karakalpakstan, / is an autonomous republic of Uzbekistan. It occupies the whole northwestern part of Uzbekistan. The capital is Nukus (' / ). The Republic of Karakalpakstan has an area of , and a population of about two million. Its territory covers the classical land of Khwarezm, which in classical Persian literature was known as (). History From about 500 BC to 500 AD, the region of what is now Karakalpakstan was a thriving agricultural area supported by extensive irrigation. It was strategically important territory and fiercely contested, as is seen by the more than 50 Khorezm Fortresses which were constructed here. The Karakalpak people, who used to be nomadic herders and fishers, were first recorded by foreigners in the 16th century. Karakalpakstan was ceded to the Russian Empire by the Khanate of Khiva in 1873. Under Soviet rule, it was an autonomous area within the Russian Soviet Federative Socialist Republic before ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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