Search results for "Formula"

showing 10 items of 755 documents

A Unifying Framework for Perturbative Exponential Factorizations

2021

We propose a framework where Fer and Wilcox expansions for the solution of differential equations are derived from two particular choices for the initial transformation that seeds the product expansion. In this scheme, intermediate expansions can also be envisaged. Recurrence formulas are developed. A new lower bound for the convergence of theWilcox expansion is provided, as well as some applications of the results. In particular, two examples are worked out up to a high order of approximation to illustrate the behavior of the Wilcox expansion.

Differential equationGeneral MathematicsEquacions diferencials01 natural sciencesUpper and lower bounds010305 fluids & plasmas0103 physical sciencesConvergence (routing)Fer expansionComputer Science (miscellaneous)Applied mathematicsZassenhaus formula010306 general physicsEngineering (miscellaneous)Mathematicslcsh:MathematicsBellman problemWilcox expansionOrder (ring theory)lcsh:QA1-939Exponential functionTransformation (function)sequences of linear transformationsProduct (mathematics)Scheme (mathematics)MatemàticaMathematics
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Electronic structure and transport properties of the Heusler compound Co2TiAl

2009

The properties of the Heusler compound Co2TiAl were investigated in detail by experimental techniques and theoretical methods. X-ray diffraction measurements indicate that as-cast samples of the compound exhibit the L21 structure with a small amount of B2-type disorder. This leads to a reduced saturation magnetization per formula unit of 0.747 μB. The Curie temperature is approximately 120 K. The transport properties are influenced by the change in the electronic structure at the Curie temperature, as revealed experimentally by conductivity, thermal transport and specific heat measurements. Different theoretical models based on ab initio calculations of the electronic structure are used to …

DiffractionAcoustics and UltrasonicsCondensed matter physicsChemistryElectronic structureengineering.materialConductivityCondensed Matter PhysicsHeusler compoundSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsThermal transportAb initio quantum chemistry methodsFormula unitengineeringCurie temperatureJournal of Physics D: Applied Physics
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New rotational levels in $^{186}$Re nucleus

2020

International audience; Excited levels of 186 Re have been studied using results of the single γ -ray spectra measurements following the thermal neutron capture reaction. Energies and intensities of more than 500 γ -transitions have been obtained with the high-resolution crystal diffraction spectrometer GAMS5 of ILL. Most of the obtained intense γ -transitions have been placed in the 186 Re level scheme. A number of new levels, as well as the depopulation for levels observed earlier in the 187 Re (p,d)186 Re reaction measurements have been proposed. Structure of 186 Re levels is interpreted in terms of two-quasiparticle plus rotor coupling model and compared with that of the neighbouring do…

DiffractionNuclear and High Energy PhysicsCore plus two-quasiparticles model[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th]Thermal neutron captureNUCLEAR REACTION 185Re[formula omitted]E=thermalMeasured [formula omitted]01 natural sciencesSpectral lineCrystalMeasured Eγ0103 physical sciencesmedicineγ)010306 general physicsPhysicsCouplingSpectrometer010308 nuclear & particles physics186 Re deduced levelsNUCLEAR REACTION 185 Re (nmedicine.anatomical_structureE =thermalExcited stateGAMS5 crystal diffraction spectrometerAtomic physicsNucleus186Re deduced levels
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Three-dimensional behavior of apodized nontelecentric focusing systems.

2002

The scalar field in the focal volume of nontelecentric apodized focusing systems cannot be accurately described by the Debye integral representation. By use of the Fresnel–Kirchhoff diffraction formula it is found that, if the aperture stop is axially displaced, the focal-volume structure is tuned. We analyze the influence of the apodizing function and find that, whereas axially superresolving pupil filters are highly sensitive to the focal-volume reshaping effect, axially apodizing filters are more inclined to the focal-shift effect.

DiffractionPhysicsbusiness.industryMaterials Science (miscellaneous)Astrophysics::Instrumentation and Methods for AstrophysicsPhysics::OpticsIndustrial and Manufacturing EngineeringKirchhoff's diffraction formulasymbols.namesakeOpticsApodizationsymbolsFresnel numberBusiness and International ManagementbusinessAxial symmetryScalar fieldFresnel diffractionDebyeApplied optics
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Corrected whole blood biomarkers : the equation of Dill and Costill revisited

2018

An exercise bout or a dehydration often causes a reduction in plasma volume, which should be acknowledged when considering the change in biomarkers before and after the plasma changing event. The classic equation from Dill and Costill (1974, J. Appl. Physiol., 37, 247–248) for plasma volume shift is usually utilized in such a case. Although this works well with plasma and serum biomarkers, we argue in this note that this traditional approach gives misleading results in the context of whole blood biomarkers, such as lactate, white cells, and thrombocytes. In this study, we demonstrate that to calculate the change in the total amount of circulating whole blood biomarker, one should utilize a …

Dill and Costill equationveribiomarkerplasma changebiomarkkeritveriplasmasense organscorrection formula
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Analytical prediction of ultimate moment and curvature of RC rectangular sections in compression

2013

This paper presents closed form expressions linking the ultimate bearing capacity to the ultimate curvature of rectangular RC sections subjected to axial load and bending moment acting in one of the two symmetry planes of the section. With respect to possible simplified formulations the following effects are also considered: confinement of the concrete, hardening of the longitudinal reinforcement, and presence of reinforcing bars distributed orthogonally to the neutral axis. The formulation is proposed in dimensional terms after a preliminary definition of the geometrical and mechanical parameters governing the structural response of the class of sections considered. The analytical expressi…

Dimensionless formulationCurvatureUniaxial bendingUltimate stateultimate limit stateBearing capacityRC columnsGeophysicMathematicsCivil and Structural EngineeringTension (physics)business.industryRC columnStructural engineeringBuilding and ConstructionCompression (physics)Geotechnical Engineering and Engineering GeologySymmetry (physics)Moment (mathematics)Settore ICAR/09 - Tecnica Delle CostruzioniRC columns uniaxial bending rectangular cross-sections dimensionless formulation ultimate limit state; RC columns; uniaxial bending; rectangular cross-sections; dimensionless formulation; ultimate limit stateGeophysicsBending momentrectangular cross-sectionsRC columns uniaxial bending rectangular cross-sections dimensionless formulation ultimate limit statebusinessNeutral axis
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A remark on absolutely continuous functions in ℝ n

2006

We introduce the notion ofα, λ-absolute continuity for functions of several variables and we compare it with the Hencl’s definition. We obtain that eachα, λ-absolutely continuous function isn, λ-absolutely continuous in the sense of Hencl and hence is continuous, differentiable almost everywhere and satisfies change of variables results based on a coarea formula and an area formula.

Discrete mathematicsChange of variablesContinuous functionGeneral MathematicsAlmost everywhereQuasi-continuous functionCoarea formulaDifferentiable functionAlgebra over a fieldAbsolute continuityMathematicsRendiconti del Circolo Matematico di Palermo
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Minimal Morse flows on compact manifolds

2006

Abstract In this paper we prove, using the Poincare–Hopf inequalities, that a minimal number of non-degenerate singularities can be computed in terms only of abstract homological boundary information. Furthermore, this minimal number can be realized on some manifold with non-empty boundary satisfying the abstract homological boundary information. In fact, we present all possible indices and types (connecting or disconnecting) of singularities realizing this minimal number. The Euler characteristics of all manifolds realizing this minimal number are obtained and the associated Lyapunov graphs of Morse type are described and shown to have the lowest topological complexity.

Discrete mathematicsLyapunov functionTopological complexityBoundary (topology)Type (model theory)Morse codeManifoldLyapunov graphslaw.inventionsymbols.namesakePoincaré–Hopf inequalitieslawEuler's formulasymbolsGravitational singularityGeometry and TopologyMathematics::Symplectic GeometryConley indexMathematicsTopology and its Applications
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Radon–Nikodym Property and Area Formula for Banach Homogeneous Group Targets

2013

We prove a Rademacher-type theorem for Lipschitz mappings from a subset of a Carnot group to a Banach homogeneous group, equipped with a suitably weakened Radon-Nikodym property. We provide a metric area formula that applies to these mappings and more generally to all almost everywhere metrically differentiable Lipschitz mappings defined on a Carnot group. peerReviewed

Discrete mathematicsMathematics::Functional AnalysisProperty (philosophy)General Mathematicsmetric area formulata111Mathematics::Analysis of PDEsCarnot groupBanach homogeneous groupsalmost everywhere differentiabilityRadon-Nikodym propertyLipschitz continuityRadon–Nikodym theoremBanach homogeneous groups; metric area formula; almost everywhere differentiability; Radon-Nikodym propertyMetric (mathematics)Homogeneous groupMathematics::Metric GeometryAlmost everywhereDifferentiable functionMathematics
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A new Euler–Mahonian constructive bijection

2011

AbstractUsing generating functions, MacMahon proved in 1916 the remarkable fact that the major index has the same distribution as the inversion number for multiset permutations, and in 1968 Foata gave a constructive bijection proving MacMahon’s result. Since then, many refinements have been derived, consisting of adding new constraints or new statistics.Here we give a new simple constructive bijection between the set of permutations with a given number of inversions and those with a given major index. We introduce a new statistic, mix, related to the Lehmer code, and using our new bijection we show that the bistatistic (mix,INV) is Euler–Mahonian. Finally, we introduce the McMahon code for …

Discrete mathematicsMultisetMathematics::CombinatoricsApplied MathematicsMajor indexMajor indexConstructiveCombinatoricssymbols.namesakeConstructive bijectionLehmer codeBijectionEuler's formulasymbolsInversion numberDiscrete Mathematics and CombinatoricsPermutation (bi)statisticStatisticMathematicsDiscrete Applied Mathematics
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