ModelN can refer to Ford ModelN , a type of car ModelN, Inc. , a software company ModelN, a musical band based in Chicago, IL USA. disambig Long comment to avoid being listed on short pages ... more details
DISPLAYTITLE n vector model The n vector model or O nmodel is one of the many highly simplified models in the branch of physics known as statistical mechanics . In the n vector model, n component, unit length, classical spin physics spins math mathbf s i math are placed on the vertices of a lattice group lattice . The Hamiltonian mechanics Hamiltonian of the n vector model is given by math H J sum i,j mathbf s i cdot mathbf s j math where the sum runs over all pairs of neighboring spins math i,j math and math cdot math denotes the standard Euclidean inner product. Special cases of the n vector model are math n 0 math The Self avoiding walk Self Avoiding Walks SAW math n 1 math The Ising model math n 2 math The XY model math n 3 math The Heisenberg model classical Heisenberg model math n 4 math Toy model for the Higgs sector of the Standard Model The general mathematical formalism used to describe and solve the n vector model and certain generalizations are developed in the article on the Potts model . References P.G. de Gennes, Phys. Lett. A, 38, 339 1972 noticed that the math n 0 math case corresponds to the SAW George Gaspari, Joseph Rudnick, Phys. Rev. B, 33, 3295 1986 discuss the model in the limit of math n math going to 0. Category Lattice models physics stub ... more details
ModelN, Inc. is a software company that is headquartered in Redwood Shores , California with offices in Princeton, New Jersey Princeton , Chicago , Hyderabad, Andhra Pradesh Hyderabad , and London . Founded in 1999, its primary focus is revenue management software for pharmaceutical and medical device companies such as Pfizer , Boston Scientific , Medtronic and Bristol Myers Squibb . In the spring of 2006, ModelN completed an acquisition of Azerity , a software company that focused on pricing and quoting practices for the high tech industry. Due to this acquisition, ModelN serves high tech customers such as ON Semiconductor . ModelN s founder and CEO , Zack Rinat , is a veteran Silicon Valley entrepreneur and former CEO of NetDynamics . External links http www.modeln.com ModelN website coord 37.5370 122.2584 display title Category Software companies of the United States Category Companies based in California US software company stub ... more details
Infobox Automobile image Image Ford N.jpg 250px 1907 Ford Model R roadster name Ford ModelN manufacturer Ford Motor Company production 1906&ndash 1908 br 13,250 produced predecessor Ford Model F successor Ford Model T class Entry level car platform body style 2 row Phaeton body phaeton engine 149CID ... 1,050lbs. 1907 ModelN ref cite book last Kimes first Beverly title standard catalog of American Cars 1805 1942 year 1996 publisher Krause publications isbn 0 87341 428 4 ref 1,400lbs. 1907 Model R ... 1996 publisher Krause publications isbn 0 87341 428 4 ref aka Ford Model R br Ford Model S fuel economy fuel capacity related similar designer Henry Ford The Ford ModelN is an automobile produced by the Ford Motor Company . It was introduced in 1906 as a successor to the Models Ford Model A 1903 A , Ford Model C C and Ford Model F F as the company s inexpensive entry level line. The ModelN diverged ... ModelN s are maroon ref http www.oldcarbrochures.com static NA Ford 1906 Ford 1906 Ford 20Advance Brochure 1906 20Ford 202.html ref . Model R The Model R was a higher trim level of the ModelN with a larger ... publications isbn 0 87341 428 4 ref , and an oil lamp. Model R was 750, 150 above the 600 base ModelN. The Model R was only produced in 1907, from April through October, and 2500 were sold ref cite ... Krause publications isbn 0 87341 428 4 ref . Its color was red. Model S The Model S was another adaptation of the ModelN. Ford s last right hand steering model, ref Clymer, p.120. ref it featured a more ... vehicles ModelN Category Motor vehicle manufacturers based in Michigan Category History of Detroit, Michigan Category Motor vehicles manufactured in the United States Brass auto stub cs Ford modelN de Ford Modell N es Ford N it Ford ModelN pt Ford ModelN ru Ford ModelN sco Ford ModelN ... m . A successful model, 7000 cars were made until production ended in 1908. At 500 the car ... New York Bonanza Books, 1950 , p.32. ref Western Tool Works automobile company Western s Gale Model ... more details
The math Z N math model is a simplified statistical mechanics statistical mechanical spin model . It is a generalization of the Ising model . Although it can be defined on an arbitrary Graph mathematics graph , it is Integrable system integrable only on one and two dimensional Lattice model physics lattices , in several special cases. Definition The math Z N math model, sometimes known as the clock model, is defined by assigning a Spin model spin value at each node math r math on a graph, with the spins taking values math s r exp frac 2 pi i q N math , where math q in 0,1, ldots,N 1 math . The spins ... can think of the spins assigned to each node of the math Z N math model as pointing in any one of math N math equidistant directions. The Boltzmann factor Boltzmann weights for a general edge math rr math are math w left r,r right sum k 0 N 1 x k left rr right left s r s r right k math where math ... of solutions to the math Z N math model defined on an in general anisotropic square lattice. If the model ... system integrability , to hold, it is possible to find the solution math x n left alpha right prod k 0 n 1 frac sin left pi k N alpha 2N right sin left pi left k 1 right N alpha 2N right math with math x 0 1 math . This particular case of the math Z N math model is often called the FZ model in its own right, after V.A. Fateev and A.B. Zamolodchikov who first calculated this solution. The FZ model approaches the XY model in the limit as math N rightarrow infty math . It is also a special case ... the math Z N math model for math N 2 math , and therefore the math Z N math model ... to particular cases of the math Z N math model include the three state Potts model , with math N ... Askin Teller model where math N 4 math . References Reflist V.A. Fateev and A.B. Zamolodchikov ... to the interaction strength along the edge math rr math . Note that math x k left rr right x N k left ... alpha math math x n 1 x n left alpha right math math x n 2 x n left pi alpha right math Requiring ... more details
Infobox Aircraft Begin name ModelN image File Curtiss N 9H on ramp c1918.jpg caption Curtiss N 9H Infobox ... added to the top of the top wing. The N 9 was initially powered by a 100 hp 75 kW Curtiss OXX 6 engine. File Curtiss F and N 9 at NAS Key West.jpeg thumb US Navy N 9s and Curtiss Model F F at Naval ... Engineering Laboratory in Philadelphia , Pennsylvania . Variants File Curtiss N 9 NAS Pensacola 1918.jpg thumb A Curtiss N 9 at Naval Air Station Pensacola NAS Pensacola . ModelN 1914 two seat trainer powered by 100 hp 75 kW Curtiss OXX engine, similar to Curtiss Model J Model J but with different aerofoil section. One built for US Army. Later rebuilt as Model O with side by side seating. ref name Bowers Curt p65 6 Bowers 1979, pp. 65 66. ref ModelN 8 Production version of N for US Army ... 1915. ref name Bowers Curt p111 2 Bowers 1979, pp. 111 112. ref ModelN 9 Two seat single engined trainer floatplane. ModelN 9N Powered by a 150 hp 112 kW Wright A piston engine. ModelN 9C The original N 9 floatplane with the 100 hp 75 kW engine, later became known as the N 9C ... trainer aircraft 1910 1919 Category Curtiss aircraft ModelN Category Seaplanes and flying boats ... Navy more users produced number built 560 variants with their own articles The Curtiss N 9 was a seaplane ..., the N 9 was equipped with a single central pontoon mounted under the fuselage. A small float ... Institute of Technology , meaning the N 9 was the first US Naval aircraft to incorporate ... s Simplex division later Wright Aeronautical . The aircraft was redesignated N 9H . A total of 560 N 9s were built during the war, most of which were H models. Only 100 were actually built by Curtiss ... Air Station. Operational history Over 2,500 US Navy pilots received their seaplane training in the N ..., several N 9s were provided to the Sperry Gyroscope Company for conversion to the Hewitt Sperry Automatic ... aerial torpedoes . The N 9s were retired by the Navy in 1927, as more modern trainers became ... more details
Model A may refer to Ford Model A 1927 1931 , a model of car built by the Ford Motor Company Ford Model A 1903 1904 , a model of car built by the Ford Motor Company One of the letter series models of Farmall tractors One of the letter series models of John Deere tractors by Deere & Company A structural model of personality in Socionics see Socionics Model A Socionics Model A Model A band , an art rock band from California A character mode in the video game Mega Man ZX Advent Ritz Model A , ultralight aircraft disambig ... more details
TOC right Wiktionary modelModel may refer to Physical Physical model , a physical representation of an object Scale model , a replica or prototype of an object 3D modelling , a 3D polygonal representation of an object, usually displayed with a computer Model aircraft Car modelModel building , a hobby ... of the solid parts of an object, also called in vitro models Model organism , a simple organism used as model in biology Model product , an identifier of a product given by its manufacturer also called model number . Human models Model art , a person who poses to be depicted in art, for example in art school Model person , a person employed to display his or her looks or something such as a commercial product Fetish model , a model who wears the clothing and or devices of sexual fetishes Promotional model , a person who interacts with consumers to draw attention to and often inform them about a product Pseudo model , lang mo u a term coined in Hong Kong for young would be models Role model , a person who serves as a behavioural or moral example to others Nonphysical Abstract Conceptual model , a nonphysical model Interpretation logic , a model is part of an interpretation of facts in logic, a mapping of truth values to sentences. Mathematical model , an abstract model that uses mathematical language Structure mathematical logic , in model theory often called just a model or semantic model Applied Business model , a framework of the business logic of a firm Causal model , an abstract model that uses cause and effect logic Computer model , a computer program which attempts to simulate an abstract model of a particular system Molecular model , a physicochemical or mathematical description that models the behaviour of molecules Data model , a description of database structure Economic model , a theoretical construct representing economic processes Ecosystem model , a representation of components and flows through an ecosystem Graphical model , a probabilistic model for which ... more details
The T Model is a formula that states the returns earned by holders of a company s stock in terms of accounting ... the period book value The T Model connects fundamentals with investment return, allowing an analyst ... in, the T Model gives a close approximation of actually realized stock returns ref Estep, Tony, Security ..., it has the advantage of being correct in a mathematical sense see T Model Derivation derivation ... and Richard Lynn, Is The Estep T Model Consistently Useful? Financial Analysts Journal, November ... techniques such as price earnings or the simplified dividend discount model it is mathematically ... Estep published a T Model The Cash Flow T Model version of the T Model driven by cash items cash ... models such as the Capital Asset Pricing Model and its various descendants financial models attempt ... PB PB mathit 1 g math Substituting 3 and 4 into 2 gives 1 , the T Model. The Cash Flow T Model In 2003 Estep published a version of the T Model that does not rely on estimates of Return on Equity, but rather ... from the balance sheet. The Cash flow T Model is math mathit T frac mathit CF mathit P boldsymbol ..., and Investment Returns , The Journal Of Portfolio Management, Spring 2003 ref that this model is mathematically identical to the original T Model, and gives identical results under certain simplifying ... it may be preferable to the standard T Model, because the specific accounting items used as input values ... valuation formulas and techniques can be understood as simplified cases of the T Model. For example ... period. The third term of the T Model becomes zero, and the remaining terms simplify to math ... Gordon yield plus growth model. It will be a correct estimate of T if PB does not change ... and the required return, T . The T Model is also closely related to the P B ROE model of Wilcox ref Wilcox, Jarrod W., The P B ROE Valuation Model, Financial Analysts Journal, Jan Feb 1984, pp 58 66 ... dei rendimenti azionari il T model, Economia & Management 1988, v. 2, p. 93 104 http www.northinfo.com ... more details
otheruses N disambiguation DISPLAYTITLE n The italicized letter n is used in mathematics to denote an arbitrary number usually an integer . n ary code n ary code n ary group n ary group n back n back n body problem n body problem n category n category n category number n category number n connected n connected n curve n curve n dimensional space n dimensional space n dimensional sequential move puzzle n dimensional sequential move puzzle n electron valence state perturbation theory n electron valence state perturbation theory NEVPT n entity n entity n flake n flake n gram n gram n group category theory n group n monoid n monoid n player game n player game n skeleton n skeleton n sphere n sphere n vector n vector n vector modeln vector model Disambig Category Prefixes ... more details
About the letter pp move indef small yes Latin alphabet navbox uc N lc nN IPAc en icon n English alphabet Letter names named en ref N Oxford English Dictionary, 2nd edition 1989 Merriam Webster s Third ... snake symbol to represent N, because their word for snake may have begun with that sound. However ... value of the letter was IPA n as in Greek language Greek , Etruscan language Etruscan , Latin and all modern languages. class wikitable bgcolor EEEEEE Egyptian hieroglyph for J Phoenician N Etruscan N ... that use the Latin alphabet. A common digraph orthography digraph with n is ng , which represents ... . Often, before a velar stop velar plosive as in ink or jungle , n alone represents a velar nasal. In languages ... for this sound is nh while Spanish and a few other languages use the letter . In English, n is generally silent when it is preceded by an m at the end of words, as in hymn however, n is pronounced in this combination ... Alphabet , the lowercase IPA n represents the alveolar nasal sound. A small capital IPA represents the uvular nasal . n is the sixth most common letter and the second most commonly used consonan in the English language after t . Mathematics In mathematics , the italic form n is the common symbol ... N math is often used to refer to the set of natural number s. Related letters and other similar ... letter I Latin letter N with acute Latin letter N with tilde Latin letter N with caron ... align right character colspan 2 N colspan 2 n align center align right Unicode name colspan 2 small LATIN CAPITAL LETTER N small colspan 2 small LATIN SMALL LETTER N small align left character encoding ... reps NATO November Morse Character N Braille References Reflist External links Commons inline N Wiktionary inline N Wiktionary inline n Latin alphabet N Category ISO basic Latin letters ace N af N als N ar N an N arc N ast N az N zh min nan N be N, be x old N bs N br N lizherenn ca N cs N co N cy N da N de N et N el N es N eo N eu N fa N fr N lettre fy N fur N gv Neaynin lettyr gd ... more details
about the abbreviation n a other uses of NA, Na and na Na disambiguation lowercase title Wiktionary n a , which uses lowercase letters, is a common abbreviation for not applicable ref name ODA cite book title Oxford Dictionary of Abbreviations year 1998 url http www.oxfordreference.com views ENTRY.html?entry t25.e13111 chapter n a publisher Oxford University Press accessdate 2010 11 14 Available online to subscribers and also in print ref or not available , used to indicate when information in a certain field on a table is not provided, either because it does not apply to a particular case in question or because it is not available. A slash is used to indicate the abbreviation of lowercase words. citation needed date July 2011 NA is an initialism which carries the same latter meaning. A slash is not used in an initialism or acronym. However, the derivative form N A is in common use. N A may also refer to Neurotics Anonymous, predecessor of Emotions Anonymous , which uses N A to distinguish itself from Narcotics Anonymous NA ref name ROEHE2004 cite journal last Roehe first Marcelo V. year 2004 month September December title Religious Experience in Self Help Groups the neurotics anonymous example journal Psicologia em Estudo volume 9 issue 3 pages 399 407 language Portuguese doi 10.1590 S1413 73722004000300008 ref References Reflist Category Initialisms Language stub ar cs N A da N A de N A es N a eo N a fr N a nl N A ja N a no N a pt N a ru N A sv N A tr N A zh N A ... more details
N S is a ship prefix for nuclear ship and is used in front of the name of a Nuclear marine propulsion nuclear powered vessel , i.e. N S Engelbrekt. See also M S Steamship S S ship type stub Category Ship types sv N S ... more details
Infobox VG title N image Image Nplus psp.png 256px developer Slick Entertainment , SilverBirch Studios ... 20 arcade n.aspx Arcade N Xbox Lives Major Nelson Bot generated title ref Nintendo DS DS , PlayStation ... E10 sup XBLA sup br PEGI 7 br OFLC PG br CERO A N is the console and handheld version of the Adobe Flash powered game, N video game N , which was developed by Metanet Software . N for Xbox Live Arcade ... were also ported separately to the PlayStation Portable ref http www.atari.com us games n plus psp The Official Playstation Portable N Website ref and Nintendo DS ref name N http www.atari.com us games n plus ds The Official Nintendo DS N Website ref by developers SilverBirch Studios and Atari . ref ... ref Metanet Software licensed their N IP for this deal, provided single player level design for both ... n and puzzle quest date 2008 07 22 accessdate 2008 07 27 title XBLA DLC this Wednesday N and Puzzle ... www.atari.com us games n plus ds Atari US N Nintendo DS Bot generated title ref ref http www.atari.com us games n plus psp Atari US N PSP system Bot generated title ref Gameplay N plays with only three ... can still come swift and often, a key design feature of N . Anything that is dangerous to the ninja ... modes in addition to the features of the XBLA version. Multiplayer N features three types of multiplayer ... blog ?p 512 metablog Mailbag N Big Brain Academy ref Development Metanet Software joined forces with Klei Entertainment Inc. to develop a version of N for the Xbox Live Arcade . ref http www.harveycartel.org metanet news.html Metanet Software N development announcement ref ref http www.xblarcade.com node 8 Discussion on N release onto the XBLA service ref Klei Entertainment partnered with a new studio called Slick Entertainment, which took over the development work for N . Metanet ... co op and 50 multi player race levels from the original, N, restyled for N . It also contains some ... B compilation yes MC 83 GR 84 The Xbox Live Arcade version of N scored favorably amongst critics ... more details
This N That is a memoir written by the actress Bette Davis and Michael Herskovitz, first published in 1987. As Davis had already written a successful autobiography, The Lonely Life , published in 1962, she had discussed in some detail the most important years of her acting career. This N That did not repeat those details, and therefore contained very little information about the period before 1962, and concentrated on Davis s acting career of the 1970s and 1980s. Much of her writing concerned her recent illness and recovery from a major stroke . This N That was published after her daughter B. D. Hyman s memoir My Mother s Keeper 1985 , in which Hyman depicted Davis as an alcoholic, overbearing shrew. Davis referred to Hyman in her book with pride and affection throughout however, a final chapter was in the form of a letter addressed Dear Hyman, in which Davis expressed her sense of betrayal. Davis and Hyman reportedly remained estranged until Davis death in 1989. The tensions between the two women were widely reported during the marketing of both books. Editions This N That , Bette Davis and Michael Herskovitz, Putnam Publishing Group, March 1987, ISBN 0 399 13246 5, hardcover, 207 pages. br This N That , Bette Davis and Michael Herskovitz, Berkley Publishing Group, March 1988, ISBN 0 425 10624 1, paperback References reflist unreferenced date January 2007 Category 1987 books Category Show business memoirs ... more details
About the novella by Stephen King the letter N Infobox short story See Wikipedia WikiProject Novels or Wikipedia WikiProject Books name N. title orig author Stephen King country United States language ... publication type publisher media type pub date November 11, 2008 preceded by followed by N. is a novella ... suspects it was due to a patient Johnny referred to in his notes only as the eponym ous N. In the inner circle of the narrative, N. is diagnosed by Dr. John Bonsaint as suffering from obsessive compulsive disorder and paranoid delusions related to keeping balance . N. has become convinced that a circle ... Cthun, is trying to break through. N. s obsession eventually leads to his death by suicide, despite ... that N. might not have been delusional after all when he suffers from the same symptoms as his ... as Stephen King s N. , a multi part graphic video series, as part of the marketing campaign for King ... news 121699557028597.htm title Marvel Bringing Stephen King s N To Your Phone last Powers ... Ben Shenkman . ref name ref1 ref name ref2 cite web url http mashable.com 2008 07 25 stephen king n title Stephen King s Unpublished N. Coming to Your Cell Phone last Hodson first Steven date July 25, 2008 accessdate 2008 07 30 ref ref http teaandscandal.co.uk 2008 07 26 stephen kings n dead link date ... the first issue of a comic book adaptation of N. , a four issues limited series . ref cite web url http www.newsarama.com comics 091221 Stephen King N Marvel.html title Marvel Brings STEPHEN KING s N To Comics publisher NEWSarama ref ref cite web url http www.dreadcentral.com news 35075 marvel publish graphic novel based stephen kings n title Marvel to Publish Graphic Novel Based on Stephen King s N. publisher DreadCentral ref See also portal Novels Short fiction by Stephen King External links http www.marvel.com videos 383.Stephen King apos s apos apos N dot apos apos colon Behind the Scenes ... websites zh N. ... more details
Poincar model can refer to Poincar disk model , a model of n dimensional hyperbolic geometry Poincar half plane model , a model of two dimensional hyperbolic geometry Mathdab ru ... more details
in rangle math of set theory. If M is a model of math L math describing a set theory and N is a class set theory class of M such that math langle N, in M, ldots rangle math is a model theory model of T containing all ordinal number ordinals of M then we say that N is an inner model of T in M . ref ... Neumann universe V , or sometimes of a generic extension of V This term inner model is sometimes applied to models which are class set theory proper classes the term set model is used for models which are sets. A model of set theory is called standard if the element relation of the model is the actual element relation restricted to the model. A model is called transitive when it is standard and the base class is a transitive class of sets. A model of set theory is often assumed to be transitive ... a standard model of ZFC in a given universe is stronger than the assumption that there exists a model. In fact, if there is a standard model, then there is a smallest standard model called the Minimal model set theory minimal model contained in all standard models. The minimal model contains no standard model as it is minimal but assuming the consistency of ZFC it contains some model of ZFC by the Godel completeness theorem. This model is necessarily not well founded otherwise its Mostowski collapse would be a standard model. It is not well founded as a relation in the universe ... model there is a model of ZFC but there is no standard model of ZFC. Use Usually when one talks about ... that the model under discussion is an inner model of ZFC. However, it is not uncommon to talk about ... KP as well. Related ideas It was proved by G del Kurt G del that any model of ZF has a least inner model of ZF which is also an inner model of ZFC Generalized Continuum Hypothesis GCH , called the constructible universe , or L . There is a branch of set theory called inner model theory which studies ways of constructing least inner models of theories extending ZF. Inner model ... more details
N , S rangle math is a prime model. References Citation last1 Chang first1 Chen Chung last2 Keisler first2 H. Jerome author2 link Howard Jerome Keisler title Model Theory origyear 1973 publisher Elsevier ...In mathematics , and in particular model theory , a prime model is a model abstract model which is as simple as possible. Specifically, a model math P math is prime if it admits an elementary embedding into any model math M math to which it is elementarily equivalent that is, into any model math M math ... model , prime models are restricted to very specific cardinality cardinalities by the L wenheim ... T math a complete theory over math L, math then this theorem guarantees a model for math T math of cardinality math kappa math therefore no prime model of math T math can have larger cardinality since at the very least it must be elementarily embedded in such a model. This still leaves much ambiguity ... models. Half of this duality is discussed in the article on saturated model s, while the other half is as follows. While a saturated model realizes as many type model theory type s as possible, a prime model realizes as few as possible it is an atomic model mathematical logic atomic model , realizing ... be interpreted in the sense that a prime model admits no frills any characteristic of a model which is optional is ignored in it. For example, the model math langle mathbb N , S rangle math is a prime model of the theory of the natural numbers N with a successor operation S a non prime model might be math langle mathbb N mathbb Z , S rangle , math meaning that there is a copy of the full integers which lies disjoint from the original copy of the natural numbers within this model in this add ... distinct elements have the same successor No element satisfies S sup n sup x x with n 0. These are, in fact ... s axioms . Any model of this theory consists of disjoint copies of the full integers in addition ... 1990 Category Model theory ... more details
Unreferenced date June 2009 In mathematics , a Kleinian model is a model of a three dimensional hyperbolic manifold N by the quotient space math mathbb H 3 Gamma math where is a discrete group discrete subgroup of PSL 2, C . Here, the subgroup , a Kleinian group , is defined so that it is isomorphic to the fundamental group math pi 1 N math of the surface N . Many authors use the terms Kleinian group and Kleinian model interchangeably, letting one stand for the other. See also hyperbolic 3 manifold . main Klein model Many properties of Kleinian models are in direct analogy to those of Fuchsian model s however, overall, the theory is less well developed. A number of unsolved conjectures on Kleinian models are the analogs to theorems on Fuchsian models. References refs Category Hyperbolic geometry Category Kleinian groups ... more details
Affleck, Large n limit of the Heisenberg Hubbard model Implications for high Tc superconductor ,Phys ...Expert subject Physics date March 2009 Refimprove date March 2009 A spin model is a mathematical model used in physics primarily to explain magnetism . Spin models may either be classical spin models classical or quantum spin model quantum mechanical in nature. Spin models have been studied in quantum field theory as examples of integrable model s. Spin models are also used in quantum information theory and computability theory in theoretical computer science . The theory of spin models is far reaching and unifying topic that cuts across many fields. Introduction In ordinary material s, the magnetic dipole moments of individual atoms produce magnetic fields that cancel one another, because each dipole points in a random direction. Ferromagnet ic materials below their Curie temperature , however, exhibit magnetic domain s in which the atomic dipole moments are locally aligned, producing a macroscopic, non zero magnetic field from the domain. These are the ordinary magnets with which we are all familiar. The study of the behavior of such spin models is a thriving area of research in condensed matter physics . For instance, the Ising model describes spins dipoles that have only two possible states, up and down, whereas in the Heisenberg model the spin vector is allowed to point in any direction. These models have many interesting properties, which have led to interesting results in the theory of phase transition s. See also Ising model Heisenberg model classical Classical Heisenberg model Heisenberg model quantum Quantum Heisenberg model Quantum rotor model Kuramoto model ANNNI model Potts model XY model Hubbard model t J model J1 J2 model Bethe ansatz Yang Baxter equation Magnetism Spin physics Spin Spin waves Spin stiffness Majumdar Ghosh Model References reflist Zur Theorie der Metalle DOI 10.1007 BF01341708 http www.springerlink.com content g86x6317566uh2x6 http www.springerlink.com ... more details
unreferenced date April 2007 In physics , a sigma model is a physical system that is described by a Lagrangian density of the form math mathcal L phi 1, phi 2, ldots, phi n sum i 1 n sum j 1 n g ij mathrm d phi i wedge mathrm d phi j math Depending on the scalars g sub ij sub it is either a linear sigma model or a non linear sigma model . The fields math phi i math , in general, provide a map from a base manifold called the worldsheet and a target Riemannian manifold that is often understood to be the spacetime . A basic example is provided by quantum mechanics which is a quantum field theory in one dimension. It s a sigma model with a base manifold given by the real line parameterizing the time or an interval, or the circle, etc. and a target space that is the real line. quantum stub Category Quantum field theory Category Physical systems ... more details
Noref date August 2009 In nuclear physics , the chiral model is a Phenomenology particle physics phenomenological model describing meson s in the chiral limit where the masses of the quark s go to zero without mentioning quarks at all . It s a nonlinear sigma model with the principal homogeneous space of the Lie group special unitary group SU N as its target manifold where N is the number of quark flavor s. The Riemannian metric of the target manifold is given by a positive constant multiplied by the Killing form acting upon the Maurer Cartan form of SU N . The internal global symmetry of this model is SU N sub L sub × SU N sub R sub , the left and right copies respectively where the left copy acts as the group action left action upon the target space and the right copy acts as the group action right action . The left copy describes rotations among the left handed quarks while the right copy describes rotations among the right handed quarks and they are independent of each other. This model admits topological soliton s called Skyrmion s. Category Quantum field theory Category Quantum chromodynamics Category Nuclear physics Quantum field theories particle stub ... more details
Weissberger s modified exponential decay model , or simply, Weissberger s model , is a Radio propagation model radio wave propagation model that estimates the path loss due to the presence of one or more trees in a point to point telecommunication link. This model belongs to the category Foliage or Vegetation models. Applicable to under conditions This model is applicable to the cases of line of sight propagation. Example is microwave transmission. This model is only applicable when there is an obstruction made by some foliage in the link. i.e. In between the transmitter and receiver. This model is ideal for application in the situation where the LOS path is blocked by dense, dry and leafy trees. Coverage Frequency 230 MHz to 95 GHz ref name Ref1 Radio propagation in cellular networks, N. Blaunstein ref Depth of Foliage up to 400 m History Formulated in 1982, this model is a development of the ITU Model for Exponential Decay MED . Mathematical formulation Weissberger s model is formally expressed as math L begin cases 1.33 , f 0.284 , d 0.588 , mbox , if 14 d le 400 0.45 , f 0.284 , d , , , , , , , , , , mbox , if 0 d le 14 end cases math where, L The loss due to foliage. Unit decibel s dB f The transmission frequency. Unit gigahertz GHz d The depth of foliage along the path. Unit meter s m Points to note The equation is scaled for frequency specified in GHz range. Depth of foliage must be specified in meters m . Limitations This model is significant for frequency range 230 MHz to 95 GHz only, as pointed out by Blaunstein. This model does not define the operation if the depth of vegetation is more than 400 m. This model predicts the loss due to foliage. The path loss must be calculated with inclusion of the free space loss. ref Introduction to RF propagation, John S. Seybold ..., John Wiley and Sons. Radio Propagation in Cellular Networks, N. Blaunstein, 2000, Artech House The Mobile ... PDF accessdate 2007 02 21 See also Fresnel zone Radio propagation model External links Category ... more details
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