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Showing papers on "Antisymmetric relation published in 1992"


Journal ArticleDOI
TL;DR: In this article, the Green-Schwarz mechanism can take a generalized form, resulting from the combined action of all the antisymmetric tensors, and some of their implications for the low-energy effective field theory are pointed out.

621 citations


Journal ArticleDOI
TL;DR: In this article, the free vibration characteristics of thin-walled composite box beams with bending-twist and extension twist coupling under rotating conditions were derived using a Newtonian approach and the results showed that bending-shear coupling influences the flexural vibration frequencies of antisymmetric box beams significantly.
Abstract: This paper presents a theoretical-cum-experimental study of the free vibration characteristics of thin-walled composite box beams with bending-twist and extension-twist coupling under rotating conditions. The governing equations in generalized displacements were derived using a Newtonian approach. The composite structural model in the derivation used a solid-section approach and contained transverse shear-related couplings and appropriate cross-section warping. The free vibration characteristics of composite box beams were determined by the Galerkin method. In order to validate the theory, glass-epoxy, kevlar-epoxy and graphite-epoxy symmetric and antisymmetric box beams were fabricated using an autoclave molding technique, and tested in an in-vacuo rotor test facility for their vibration characteristics. Beam excitation in the rotating condition was effected by means of induced-strai n actuation with the help of piezoceramic bending elements. Strain gages were used to measure the response of the first three modes over a range of rotational speeds up to 1000 rpm. It was determined that the experimental frequencies and mode shapes correlated satisfactorily with the theoretical results. It is shown also that bending-shear coupling influences the flexural vibration frequencies of antisymmetric box beams significantly. Extension-shear coupling, on the other hand, does not influence the flexural-torsion vibration frequencies of symmetric box beams significantly.

112 citations


Journal ArticleDOI
M. Savoia1, J. N. Reddy1
TL;DR: In this article, the displacements in a laminated composite are represented as products of two sets of unknown functions, one of which is only a function of the thickness coordinate and the other is a function in the in-plane coordinates, and the minimization of the total potential energy is reduced to a sequence of iterative linear problems.
Abstract: The displacements in a laminated composite are represented as products of two sets of unknown functions, one of which is only a function of the thickness coordinate and the other is a function of the in-plane coordinates (i.e., separation of variables approach), and the minimization of the total potential energy is reduced to a sequence of iterative linear problems. Analytical solutions are developed for cross-ply and angle-ply laminated composite rectangular plates. The solution for simply-supported cross-ply plates under sinusoidal transverse load reduces to that of Pagano. Numerical results for stresses and is placements for antisymmetric angle-ply laminates are presented. The three-dimensional elasticity solutions developed are important because they can be used to study the behavior of composite laminates, in addition to serving as reference for approximate solutions by numerical methods and two-dimensional theories.

108 citations


Journal ArticleDOI
TL;DR: In this paper, an analytic three-dimensional elasticity solution for the thermal buckling problem of multilayered anisotropic plates is presented, where the plates are assumed to have rectangular geometry and an antisymmetric lamination with respect to the middle plane.
Abstract: Analytic three‐dimensional elasticity solutions are presented for the thermal buckling problem of multilayered anisotropic plates. The plates are assumed to have rectangular geometry and an antisymmetric lamination with respect to the middle plane. The temperature is assumed to be independent of the surface coordinates, but it has an arbitrary symmetric variation through the thickness of the plate. No external loads are present, but the motion of the plate is partially restrained in its plane. A mixed formulation is used, with the fundamental unknowns consisting of the six stress components and the three displacement components of the plate. The prebuckling deformations are taken into account. Each of the plate variables is decomposed into symmetric and antisymmetric components in the thickness direction, and is expressed in terms of a double Fourier series in the Cartesian surface coordinates. Extensive numerical results are presented showing the effects of the prebuckling deformation on the critical tem...

86 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that the antisymmetric vortex shedding energy appears as a sinuous mode at half the excitation frequency at high symmetric forcing amplitudes, above which the large-scale vortices do not form.
Abstract: Symmetric and antisymmetric periodic disturbances introduced directly into the boundary layer on a circular cylinder at low Reynolds number are shown by experiment to be capable of modifying the vortex formation process and changing the vortex shedding frequency. Spectral measurements have shown that the antisymmetric vortex shedding mode is strongly coupled to the symmetric first harmonic mode. When symmetric excitation is applied, three different shapes of the mean velocity profiles can be identified as the forcing amplitude is increased. At low forcing amplitudes nonlinear interaction between the forcing field and the natural wake oscillator produces sum and difference modes. Symmetric forcing with intermediate-amplitude disturbances suppresses the natural shedding frequency, and the dominant vortex shedding energy appears as a sinuous mode at half the excitation frequency. At high symmetric forcing amplitudes a threshold is reached, above which the large-scale vortices do not form. The symmetries of the combination modes follow two simple rules based on the symmetries of the interacting modes. The symmetry rules provide an explanation for the fundamental difference in wake structure that occurs between symmetric forcing and antisymmetric forcing.

75 citations


Journal ArticleDOI
TL;DR: In this article, the authors studied non-linear flexural vibrations of a nearly square plate when excited periodically with forces normal to the midplane of the plate are studied when the excitation frequency is near that of one of the antisymmetric modes.

48 citations


Journal ArticleDOI
TL;DR: In this paper, the Green-Schwarz mechanism can take a generalized form, resulting from the combined action of all the antisymmetric tensors, and some of their implications for the low-energy effective field theory are pointed out.
Abstract: An interesting feature of some open superstring models in $D < 10$ is the simultaneous presence, in the spectrum, of gauge fields and of a number of antisymmetric tensor fields. In these cases the Green-Schwarz mechanism can (and does) take a generalized form, resulting from the combined action of all the antisymmetric tensors. These novelties are illustrated referring to some simple rational models in six dimensions, and some of their implications for the low-energy effective field theory are pointed out.

47 citations


Journal ArticleDOI
TL;DR: In this article, the masses of s-wave bottom baryons are discussed in a semirelativistic quark model, on the basis of a quark distance relation.
Abstract: The masses of s-wave bottom baryons are discussed in a semirelativistic quark model, on the basis of a quark-distance relation. We stress that the Σ b is heavier than Ξ' b (b[su], b[sd]) containing the antisymmetric su(or sd) subsystem. We conclude that the two candidates for Λ b with very different masses are different states; Basile et al.'s result 5425 +175 −75 MeV is Λ b (b([du]), but Arenton et al.'s result ∼5750 MeV is Ξ' 0 b (b[su])

47 citations


Journal ArticleDOI
TL;DR: In this paper, the instability modes of a rectangular nozzle of aspect ratio 4 have been studied experimentally at exit Mach numbers ranging from 0.03 to 1.5, and several distinct characteristics are identified according to the arrangement of the flow structure with respect to the jet centerline.
Abstract: The instability modes of a jet issuing from a rectangular nozzle of aspect ratio 4 have been studied experimentally at exit Mach numbers ranging from 0.03 to 1.5. Depending on the exit Mach number, several distinct characteristics are identified according to the arrangement of the flow structure with respect to the jet centerline. In the very low velocity range, U ≤ 20 m/s, a symmetric mode prevails. An antisymmetric mode dominates at all other Mach numbers, except in the range 0.6 ≤ M ≤ 0.85, where both symmetric and antisymmetric modes exist and there is a continuous switching between them

36 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the scattering of arbitrary elastic waves by a circular crack in a transversely isotropic solid, where the symmetry axis of the solid and the normal to the crack are parallel.

35 citations


Journal ArticleDOI
TL;DR: In this paper, a new statistics is presented to describe particles whose state vector space carries both the symmetric and antisymmetric representations of symmetric groups, and a new statistical model is proposed to describe symmetric particles.

Journal ArticleDOI
TL;DR: In this paper, an asymptotic analysis is carried out in order to calculate the elastostatic field near the tip of a crack for the finite plane deformation of Hadamard materials.
Abstract: SUMMARY An asymptotic analysis is carried out in order to calculate the elastostatic field near the tip of a crack for the finite plane deformation of Hadamard materials. A general body configuration containing a crack and loading conditions is considered. It is shown that the singular field near the crack tip can be obtained by applying a rigid-body rotation with a subsequent parallel translation to a so-called canonical field. The adjective canonical is adopted here to denote the field in which the crack faces open symmetrically, with the most singular term of order A, just resembling the displacement field of the symmetric mode in linear fracture mechanics. No analogy with the antisymmetric mode is possible, and the crack-equilibrium criterion requires only one stress-intensity factor to be known.

Journal ArticleDOI
TL;DR: Theoretical calculations of the chemical shielding tensor using the coupled Hartree-Fock and localized orbital methods with different basis sets are compared for the ethylenic carbon atoms, which are expected to have a large antisymmetric component.
Abstract: Theoretical calculations of the chemical shielding tensor using the coupled Hartree-Fock and localized orbital methods with different basis sets are compared for the ethylenic carbon atoms, which are expected to have a large antisymmetric component, in tetrachlorocyclopropene, tetrafluorocyclopropene, dichlorocyclopropene and cyclopropene at optimized geometries. Two modest attempts, made to extrapolate these results to the Hartree-Fock limit, demonstrate that the LORG method gives the most reliable calculated results but that there is still much room for improvement. Comparison of the calculated value of the antisymmetric component of the shielding tensor for tetrachlorocyclopropene agrees approximately with the experimental value.


Journal ArticleDOI
TL;DR: In this paper, Yang et al. investigated multi-mode dynamical E⊗B Jahn-Teller coupling effects in the X 2E and A 2E states of the allene cation.

Journal ArticleDOI
TL;DR: In this article, the dynamic instability of antisymmetric angle-ply and cross-ply laminated plates, subjected to periodic inplane loads P(t) = P0 + P1 cos θt, is investigated.

Journal ArticleDOI
TL;DR: In this paper, the Coulomb interaction between electrons and holes is used to mix symmetric and antisymmetric excitons, and the experimental results show a decreasing trend with reduced coupling between the wells, as anticipated from the theoretical results with mixing of exciton states.
Abstract: Molecular-beam-epitaxy-manufactured GaAs/${\mathrm{Al}}_{0.3}$${\mathrm{Ga}}_{0.7}$As symmetric coupled-double-quantum-well (CDQW) structures covering a wide range of coupling strengths have been studied by photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy. These measurements give exciton energy levels and relative absorption strengths of exciton resonances in CDQW's. In CDQW's, the electronic states related to one-particle states in the corresponding single quantum wells split into symmetric and antisymmetric states. The exciton states constructed from products of either symmetric or antisymmetric hole and electron one-particle states are denoted ``symmetric'' and ``antisymmetric'' excitons. An important feature in the experimental PLE spectra is a significant reduction of oscillator strengths for optical transitions related to antisymmetric heavy-hole and light-hole excitons compared to the strengths of the transitions to the symmetric exciton states when the symmetry splitting becomes comparable to single-quantum-well exciton binding energies. This effect is absent in the simplest theory for CDQW's, but it can be obtained within an improved effective-mass theory. The Coulomb interaction between electrons and holes mixes symmetric exciton states with antisymmetric exciton states. We have performed variational calculations of exciton binding energies and oscillator strengths for optical transitions to excitonic states which are linear combinations of symmetric and antisymmetric exciton states. The energy levels obtained from the model with mixing between the states are in reasonable agreement with experimental results. However, the difference between the theoretical results with mixing and without mixing is too small to show that the mixing of the states is important. The experimental values for the ratios of oscillator strengths show a decreasing trend with reduced coupling between the wells, as anticipated from the theoretical results with mixing of exciton states. This demonstrates that mixing of exciton states by the Coulomb interaction is important for weakly coupled wells.

Journal ArticleDOI
TL;DR: In this article, the theory of flexural wave propagation in an elastic beam with periodic structure is developed in terms of Floquet waves, and two lemmas about the properties of the fundamental solutions are proved.
Abstract: The theory of flexural waves in an elastic beam with periodic structure is developed in terms of Floquet waves. Special relationships have been determined among the fundamental solutions of the governing equation. Two lemmas about the properties of the fundamental solutions are proved. With the help of these relations and lemmas, the analysis and classification of the dynamic nature of the problem is greatly simplified. We show that the flexural wave propagation in a periodic beam can be interpreted as the superposition of two pairs of waves propagating in opposite directions, of which one pair behaves as an attenuated wave. The dispersion spectrum of the second pair of waves shows the band structure, consisting of stopping bands and passing bands. Exploiting the symmetry of the structure, the dispersion equation at the end points of Brillouin zones is uncoupled into two simpler equations. These uncoupled equations represent the dispersion spectrum of waves which are either symmetric, or antisymmetric.

Journal ArticleDOI
TL;DR: In this article, the thermal buckling temperatures of simply supported composite angle-ply laminates subjected to a uniform-temperature field rise, predicted by various displacement fields and stress/strain/temperature relationships, were examined.

01 Jan 1992
TL;DR: In this article, the phase velocity of antisymmetric plate waves is determined through spectral analysis of signals recorded from a lead break source on the surface of graphite epoxy laminates.
Abstract: A recently developed ultrasonic techique which has been successful in monitoring the integrity of advanced structures is described. The technique is based on a two-transducer contact type arrangement that can be used to determine the dispersion curves of guided waves generated within the specimen. The phase velocity of antisymmetric plate waves is determined through spectral analysis of signals recorded from a lead break source on the surface of graphite epoxy laminates. The influence of all five stiffness constants on the dispersion curves of both symmetric and antisymmetric plate waves is theoretically investigated for propagation at 0, 45, and 90 deg to the fibers. All but c12 were found to have a strong influence on the dispersion curves in this frequency range. The fit with the theoretically predicted dispersion curves was excellent for propagation parallel and perpendicular to the fibers in the unidirectional specimen and good for the other cases considered.

Journal ArticleDOI
TL;DR: In this paper, the group of Abelian surfaces was used to develop a gauge independent quantization for the two-index antisymmetric potential, and an exact solution was found for the vacuum and the photon state, and a regularization scheme was proposed.
Abstract: We use the group of Abelian surfaces to develop a gauge-independent quantization for the two-index antisymmetric potential. An exact solution is found for the vacuum and the photon state, and a regularization scheme is proposed.

Journal ArticleDOI
TL;DR: In this article, a method of direct numerical integration of the frequency/time period expression is proposed to study the non-linear forced/free vibration behavior of rectangular, antisymmetric cross-ply plates.

Journal ArticleDOI
TL;DR: Based on the odd symmetric solutions and the property that all roots of symmetric and antisymmetric filters are on the unite circle, a method for Pisarenko's decomposition is introduced that reduces the number of iterations and the computational cost in each iteration considerably.
Abstract: Algorithms and properties of symmetric solutions of a Toeplitz system are studied. It is shown that the numbers of positive and negative eigenvalues associated with symmetric (antisymmetric) eigenvectors are the same as the numbers of positive and negative predictor errors of symmetric (antisymmetric) filters. Based on the odd symmetric solutions and the property that all roots of symmetric and antisymmetric filters are on the unite circle, a method for Pisarenko's decomposition is introduced. Compared with some other methods, it reduces the number of iterations and the computational cost in each iteration considerably. >


Journal ArticleDOI
TL;DR: An analytical solution to a moderately thick simply supported rectangular plate with SSl-type boundary conditions for antisymmetric angle-ply laminations, subjected to transverse loads, is presented in this article.

Journal ArticleDOI
TL;DR: In this article, the quantum field theory of particles obeying new kinds of quantum statistics, called orthofermi and orthobose statistics, was constructed, where the wave function is antisymmetric (symmetric) in one set of indices while no particular symmetry is required for the other set.
Abstract: We construct the quantum field theory of particles obeying new kinds of quantum statistics, called orthofermi and orthobose statistics. For the orthofermions (orthobosons), the wave function is antisymmetric (symmetric) in one set of indices while no particular symmetry is required for the other set of indices. Nonrelativistic as well as relativistic quantum Held theories with interaction are constructed.

Journal ArticleDOI
TL;DR: In this paper, an experimental study of the scattering of Lamb waves at the end section of an elastic plane plate immersed in water is presented, where the amplitude of the radiated bulk wave in the water is recorded versus the angle of observation.
Abstract: An experimental study is presented of the scattering of Lamb waves at the end section of an elastic plane plate immersed in water. For antisymmetric modes as well as for symmetric ones, the amplitude of the radiated bulk wave in the water is recorded versus the angle of observation. In order to explain these patterns, a model is proposed that deals with the Lamb wave displacements inside the plate. The agreement between the theoretical and the experimental diagrams is quite good. The radiation pattern obtained for parameters corresponding to the crossing of two Lamb dispersion curves is also investigated.

Journal ArticleDOI
TL;DR: In this paper, the cosine potential energy naturally induced in theories with an antisymmetric rank two tensor field, provides a framework for understanding both inflationary cosmology and large scale structure.

Journal ArticleDOI
TL;DR: In this article, the authors used rotationally state-selected ND3 molecular beams to detect inversion symmetry change from antisymmetric to symmetric states, and demonstrated that the observed effect is due to molecular self-diffraction on the surface and that it may serve as a new way to probe the molecule surface interaction.
Abstract: By employing rotationally state‐selected ND3 molecular beams, ‖JKMe≳‖inversion≳ =‖1111≳‖−≳, and REMPI detection, it is found that there is a propensity for inversion symmetry change from antisymmetric to symmetric states, ‖−≳ to ‖+≳, as compared to antisymmetric to antisymmetric states, ‖−≳ to ‖−≳, in the scattering of ND3 on a graphite (0001) surface at 130 K. The total probability of inversion symmetry change summed over the post‐collisional rotational states is measured as a function of translational energy. We demonstrate that the observed effect is due to molecular self‐diffraction on the surface and that it may serve as a new way to probe the molecule–surface interaction. Relying on the infinite order sudden approximation [Gerber et al., J. Chem. Phys. 73, 4397 (1980)], we suggest a procedure for inverting an approximate, corrugation‐averaged molecule–surface interaction potential from experimental data on molecular self‐diffraction; measurements of the probability of inversion symmetry change for d...

Journal ArticleDOI
TL;DR: In this article, a perturbation theory for the system of coupled microstrip disk structures is presented, which is based on the electric field integral equation description of the circuit, which includes all of the wave phenomena associated with the conductors and the surrounding media.
Abstract: A full-wave perturbation theory for the system of coupled microstrip disk structures is presented. The theory is based on the electric field integral equation description of the circuit, which includes all of the wave phenomena associated with the conductors and the surrounding media. This method is suitable for quantification of nearly degenerate coupling between open microstrip disks, yielding the complex system eigenmodes. For the case of two coupled disks, the perturbation theory analytically separates, though simultaneously solves for, the symmetric and antisymmetric system eigenmodes. The development of the perturbation theory leads to good physical insight for this mode-splitting phenomena. Numerical results obtained with the perturbation theory agree well with those obtained by a more accurate method of moments solution to the coupled set of electric field integral equations, as well as with experimental data. >