References of "McFarland, D. Michael"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailSUPPRESSION OF AEROELASTIC INSTABILITIES BY BROADBAND PASSIVE TARGETED ENERGY TRANSFERS
Lee, Young S.; McFarland, D. Michael; Vakakis, Alexander F. et al

in Sixth EUROMECH Nonlinear Dynamics Conference, Saint Petersbourg, 2008 (2008, July)

We study passive and nonlinear targeted energy transfers induced by transient resonant interactions between an essentially nonlinear attachment and an in-flow rigid wing model. We show that it is feasible ... [more ▼]

We study passive and nonlinear targeted energy transfers induced by transient resonant interactions between an essentially nonlinear attachment and an in-flow rigid wing model. We show that it is feasible to partially or even completely suppress aeroelastic instabilities in the wing (limit cycle oscillations-LCOs) by passively transferring broadband vibration energy from the wing to the attachment in a one-way irreversible fashion. We study the nonlinear dynamical mechanisms that govern TET and show that they are series of transient or sustained resonance captures in different resonance manifolds of the dynamics. Aeroelastic instability suppression is performed by partially or completely eliminating the triggering mechanism for aeroelastic instability. Through numerical parametric studies we identify three main mechanisms for suppressing aeroelastic instability, and investigate them in detail, both numerically by Empirical Mode decomposition (EMD), and analytically by slow/fast partitions of the transient dynamics. [less ▲]

Detailed reference viewed: 125 (1 ULg)
Full Text
Peer Reviewed
See detailImpulsive periodic and quasi-period orbits in coupled oscillators with essential nonlinearity
Kerschen, Gaëtan ULg; Gendelman, Oleg; Vakakis, Alexander F. et al

in Communications in Nonlinear Science & Numerical Simulation (2008), 13

We study the impulsive responses of a grounded linear oscillator coupled to a light nonlinear attachment through an essentially nonlinear (nonlinearizable) stiffness. We analyze the periodic and quasi ... [more ▼]

We study the impulsive responses of a grounded linear oscillator coupled to a light nonlinear attachment through an essentially nonlinear (nonlinearizable) stiffness. We analyze the periodic and quasi-periodic dynamics of the undamped system forced by a single impulse on the linear oscillator and being initially at rest, by considering separately low-, moderateand high-energy impulsive motions. The motivation for studying the impulsive dynamics of this system centers on passive targeted energy transfer properties of the corresponding weakly damped one, that is, of the possibility of one-way, irreversible transfer of energy from the linear oscillator to the nonlinear attachment. A rather surprising aspect of this work is the complexity of the analysis required to study the impulsive dynamics of this system, due to its high degeneracy, as it undergoes a co-dimension three bifurcation. 2006 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 23 (4 ULg)
Full Text
See detailTheoretical Understanding of Targeted Energy Transfers for Suppressing Aeroelastic Instabilities in a Nonlinear Aeroelastic Test Apparatus
Lee, Young S.; McFarland, D. Michael; Kerschen, Gaëtan ULg et al

in 45th Technical Meeting of the Society of Engineering Science, Urbana Champaign, 2008 (2008)

Detailed reference viewed: 100 (0 ULg)
Full Text
Peer Reviewed
See detailEnhancing robustness of aerolastic instability suppression using MDOF energy sinks
Lee, Young S.; Vakakis, Alexander F.; Bergman, Lawrence A. et al

in AIAA Journal (2008), 46(6), 1371-1394

In this last of a three paper sequence, we use simultaneous multimodal broadband targeted energy transfers to multi-degree-of-freedom nonlinear energy sinks to improve the robustness of aeroelastic ... [more ▼]

In this last of a three paper sequence, we use simultaneous multimodal broadband targeted energy transfers to multi-degree-of-freedom nonlinear energy sinks to improve the robustness of aeroelastic instability suppression of a rigid wing with structural nonlinearities. A numerical bifurcation analysis of limit cycle oscillations of the wing with the multi-degree-of-freedom nonlinear energy sinks attached shows that controlling the lower parameter value for limit point cycle bifurcation to occur above Hopf bifurcation is crucial to enhancing the robustness of limit cycle oscillation suppression. We demonstrate that multi-degree-of-freedom nonlinear energy sinks can greatly enhance the robustness of limit cycle oscillation suppression, compared with single-degree-of-freedom nonlinear energy sinks (which were studied in our previous papers), with a much smaller total mass.We also investigate the nonlinear modal interactions that occur between the aeroelastic modes and the multi-degree-of-freedom nonlinear energy sinks, in an effort to gain a physical understanding of the mechanisms governing instability suppression. We demonstrate that a properly designed multi-degree-of-freedom nonlinear energy sink provides robustness of aeroelastic instability suppression by efficiently, passively, and rapidly transferring a significant portion of unwanted vibration energy to the furthest mass of the nonlinear energy sink. Consideration of other types of multi-degree-of-freedom nonlinear energy sinks suggests that the robustness enhancement is achieved by the concentrated mass effect of the attached nonlinear energy sinks. [less ▲]

Detailed reference viewed: 105 (2 ULg)
Full Text
Peer Reviewed
See detailEmpirical Mode Decomposition in the Reduced-Order Modeling of Aeroelastic Systems
Lee, Young S; McFarland, D. Michael; Vakakis, Alexander F. et al

in 49th AIAA Structural Dynamics and Materials Conference, Shaumberg, 2008 (2008)

A relationship between IntrinsicMode Functions (IMFs), derived from the Empirical Mode Decomposition (EMD), and the slow-flow model of a nonlinear dynamical system has been exploited in the development of ... [more ▼]

A relationship between IntrinsicMode Functions (IMFs), derived from the Empirical Mode Decomposition (EMD), and the slow-flow model of a nonlinear dynamical system has been exploited in the development of the Slow Flow Model Identification (SFMI) method for strongly nonlinear systems, in which the physical parameters of such systems are identified from experimental data. Both the slow flows and IMFs provide the means to expand a general multicomponent signal in terms of a series of simpler, dominant, monocomponent signals. The slow flows are obtained analytically, for example through application of the method of complexification and averaging (CxA), which transforms the equations of motion into a set of approximate equations in amplitude and phase for each modeled frequency component. In contrast, the EMD characterizes a signal through the envelope and phase of its elemental components, the IMFs. Thus, between nonlinear transitions, the equations derived using the CxA method govern the amplitude and phase of the modeled IMFs. Application of SFMI has, until now, been limited to low-dimensional systems subjected to impulsive excitation. Herein, the method is extended to identification of a planar rigid airfoil [less ▲]

Detailed reference viewed: 51 (1 ULg)
Full Text
Peer Reviewed
See detailEnhancing Robustness of Instability Suppression by Means of Multi-Degree-of-Freedom Nonlinear Energy Sinks
Lee, Young S.; Vakakis, Alexander F.; Bergman, Lawrence A. et al

in 48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Honolulu, 2007 (2007, April)

Multi-degree-of-freedom nonlinear energy sinks (MDOF NESs) are utilized to improve robustness of suppression of limit cycle oscillations (LCOs) due to aeroelastic instability. Bifurcation analysis by a ... [more ▼]

Multi-degree-of-freedom nonlinear energy sinks (MDOF NESs) are utilized to improve robustness of suppression of limit cycle oscillations (LCOs) due to aeroelastic instability. Bifurcation analysis by a numerical continuation technique shows that controlling occurrence of a limit point cycle (LPC or saddle-node) bifurcation point above a Hopf bifurcation point is crucial to enhancing robustness. Not only greatly can MDOF NESs enhance the robustness of suppression against even strong external disturbances, but they can also yield a similar e±ciency even with a smaller mass, compared to the SDOF NESs with the same parameter conditions. Nonlinear modal interactions between the aeroelastic modes and the MDOF NES are examined to demonstrate e±ciency of the MDOF NES. [less ▲]

Detailed reference viewed: 60 (2 ULg)
Full Text
Peer Reviewed
See detailTheoretical and experimental study of multimodal targeted energy transfer in a system of coupled oscillators
Kerschen, Gaëtan ULg; Kowtko, Jeffrey J.; McFarland, D. Michael et al

in Nonlinear Dynamics (2007), 47

The purpose of this study is the theoretical and experimental investigation of targeted energy transfers from a two-degree-of-freedom primary structure to a nonlinear energy sink (NES). It is demonstrated ... [more ▼]

The purpose of this study is the theoretical and experimental investigation of targeted energy transfers from a two-degree-of-freedom primary structure to a nonlinear energy sink (NES). It is demonstrated that an NES can resonate with and extract energy from both modes of the primary structure. By facilitating these energy transfers, notably through excitation of appropriate periodic and quasi-periodic orbits, one can promote dissipation of a major portion of externally induced energy in the nonlinear attachment. [less ▲]

Detailed reference viewed: 36 (14 ULg)
Full Text
See detailWING-FLUTTER MITIGATION BY TARGETED ENERGY TRANSFERS INDUCED BY AN ESSENTIALLY NONLINEAR ATTACHMENT
Lee, Young S.; McFarland, D. Michael; Kerschen, Gaëtan ULg et al

in International Symposium on Recent Advances in Mechanics, Dynamical Systems and Probability Theory, Palermo, 2007 (2007)

The problem to be addressed here is the mitigation of limit cycle oscillations (LCO) in a rigid in-°ow wing with nonlinear heave and pitch sti®nesses in quasi-steady °ow, using targeted energy transfer ... [more ▼]

The problem to be addressed here is the mitigation of limit cycle oscillations (LCO) in a rigid in-°ow wing with nonlinear heave and pitch sti®nesses in quasi-steady °ow, using targeted energy transfer (TET). We show through simulation and Wavelet transforms that LCO formation is a process of resonance capture, with heave response triggering the pitch LCO. With the addition of a lightweight, fully passive attachment { a nonlinear energy sink (NES) { to the wing, we analytically predict three distinct mechanisms for LCO mitigation: repeated suppressed burst-outs, partial and complete suppressions of aeroelastic instability. Subsequent wind-tunnel experiments conducted in the Nonlinear Aeroelastic Test Apparatus (NATA) at Texas A&M University fully support these results. [less ▲]

Detailed reference viewed: 117 (0 ULg)
Full Text
See detailPASSIVE SUPPRESSION OF AEROELASTIC INSTABILITIES OF IN-FLOW WINGS BY TARGETED ENERGY TRANSFERS TO LIGHTWEIGHT ESSENTIALLY NONLINEAR ATTACHMENTS
lee, Young S.; Vakakis, Alexander F.; Bergman, Lawrence A. et al

in International Forum on Aerolasticity and Strucural Dynamics, Stockholm, 2007 (2007)

Theoretical and experimental suppression of aeroelastic instabilities by means of broadband passive targeted energy transfers has been recently studied. A single-degree-offreedom (SDOF) nonlinear energy ... [more ▼]

Theoretical and experimental suppression of aeroelastic instabilities by means of broadband passive targeted energy transfers has been recently studied. A single-degree-offreedom (SDOF) nonlinear energy sink (NES) was coupled to a 2-DOF rigid wing modeled in the low-speed, subsonic regime with quasi-steady aerodynamic theory. The nonlinear attachment was designed and optimized to suppress the critical nonlinear modal energy exchanges between the flow and the (pitch and heave) wing modes, thus suppressing the (transient) triggering mechanism of aeroelastic instability. We performed bifurcation analysis to find regions of robust passive aeroelastic suppression in parameter space. Then, we employed multi-degreeof-freedom nonlinear energy sinks (MDOF NESs) to improve robustness of the aeroelastic instability suppression. Bifurcation analysis by a numerical continuation technique demonstrated that controlling the occurrence of a limit point cycle (LPC or saddle-node) bifurcation point above a Hopf bifurcation point is crucial to enhancing suppression robustness. MDOF NESs not only can enhance robustness of suppression against even strong gust-like disturbances, but they require lower NES mass compared to SDOF NES designs. The validity of the theoretical findings was proven by a series of wind tunnel experiments. [less ▲]

Detailed reference viewed: 100 (0 ULg)
Full Text
See detailThe slow-flow method of identification in nonlinear structural dynamics
Kerschen, Gaëtan ULg; Vakakis, Alexander F.; Lee, Young.S et al

in Smart Str. and Mat. & Nondestructive Eval. and Health Mon., San Diego, 2007 (2007)

The Hilbert-Huang transform (HHT) has been shown to be effective for characterizing a wide range of nonstationary signals in terms of elemental components through what has been called the empirical mode ... [more ▼]

The Hilbert-Huang transform (HHT) has been shown to be effective for characterizing a wide range of nonstationary signals in terms of elemental components through what has been called the empirical mode decomposition. The HHT has been utilized extensively despite the absence of a serious analytical foundation, as it provides a concise basis for the analysis of strongly nonlinear systems. In this paper, we attempt to provide the missing link, showing the relationship between the EMD and the slow-flow equations of the system. The slow-flow model is established by performing a partition between slow and fast dynamics using the complexification-averaging technique, and a dynamical system described by slowly-varying amplitudes and phases is obtained. These variables can also be extracted directly from the experimental measurements using the Hilbert transform coupled with the EMD. The comparison between the experimental and analytical results forms the basis of a nonlinear system identification method, termed the slow-flowmodel identification method, which is demonstrated using numerical examples. [less ▲]

Detailed reference viewed: 28 (0 ULg)
Full Text
See detailTOWARDS MULTI-SCALE NONLINEAR (AND LINEAR) SYSTEM IDENTIFICATION IN STRUCTURAL DYNAMICS
Kerschen, Gaëtan ULg; Lee, Young-Sup; Vakakis, Alexander F. et al

in 8th HSTAM International Congress on Mechanics, Patras, 2007 (2007)

The Hilbert-Huang transform (HHT) has been shown to be effective for characterizing a wide range of nonstationary signals in terms of elemental oscillatory components, termed the intrinsic mode functions ... [more ▼]

The Hilbert-Huang transform (HHT) has been shown to be effective for characterizing a wide range of nonstationary signals in terms of elemental oscillatory components, termed the intrinsic mode functions (IMFs). In this presentation, we describe a combination of methods involving numerical integral transforms and theoretical analysis that cumulate to a new nonparametric method for nonlinear system identification based on multiple slow-fast partitions of the dynamics. This method can find wide applicability to linear and (weakly or strongly) nonlinear systems with various damping and/or stiffness nonlinearities. Moreover, through this method we can systematically examine transient resonance captures in the responses of dynamically interacting nonlinear structures, hence, decomposing and identifying the underlying multimodal nonlinear modal interactions that give rise to complex phenomena. [less ▲]

Detailed reference viewed: 31 (0 ULg)
Full Text
See detailTARGETED ENERGY TRANSFER PHENOMENA FROM PRIMARY STRUCTURES TO GEOMETRICALLY NONLINEAR LIGHTWEIGHT ATTACHMENTS: AN OVERVIEW
Vakakis, Alexander F.; Kerschen, Gaëtan ULg; Bergman, Lawrence A. et al

in EUROMECH Colloquium 483 Geometrically Non-linear Vibrations of Structures, Porto, 2007 (2007)

Detailed reference viewed: 24 (0 ULg)
Full Text
See detailNonlinear MDOF System Characterization and Identification using the Hilbert- Huang Transform: Experimental Demonstration
Kerschen, Gaëtan ULg; Vakakis, Alexander F.; Lee, Young.S et al

in 25th International Modal Analysis Conference, Orlando, 2007 (2007)

The Hilbert transform is one of the most successful approaches to tracking the varying nature of vibration of a large class of nonlinear systems, thanks to the extraction of backbone curves from ... [more ▼]

The Hilbert transform is one of the most successful approaches to tracking the varying nature of vibration of a large class of nonlinear systems, thanks to the extraction of backbone curves from experimental data. Because signals with multiple frequency components do not admit a well-behaved Hilbert transform, this transform is inherently limited to the analysis of single-degree-of-freedom systems; this shortcoming is potentially overcome by the Hilbert-Huang transform (HHT). In this study, the joint application of the complexification-averaging method and the HHT enables us to develop a new technique, the slow-flow model identification method. Through an experimental application, we demonstrate that the proposed method is adequate for characterizing and identifying multi-degreeof-freedom nonlinear systems. [less ▲]

Detailed reference viewed: 61 (0 ULg)
Full Text
See detailSuppression of limit cycle oscillations with a nonlineart energy sink: theoretical basis
Lee, Young S.; Vakakis, Alexander F.; McFarland, D. Michael et al

in 47th AIAA Structural Dynamics and Materials Conference, Newport, 2006 (2006, May)

Limit cycle oscillations (LCOs) commonly require restrictions on the operation of high- performance aircraft and have the potential to cause structural damage or failure. This paper summarizes recent ... [more ▼]

Limit cycle oscillations (LCOs) commonly require restrictions on the operation of high- performance aircraft and have the potential to cause structural damage or failure. This paper summarizes recent theoretical findings on the application of passive and targeted nonlinear energy transfer (\nonlinear energy pumping") for the reduction or elimination of LCOs in self-excited systems. This NES has been used successfully to suppress LCOs of an elastically mounted, rigid airfoil in flow. The theoretical results are in agreement with experimental studies of a practical airfoil with an attached NES. These experimental results, presented in full in a separate paper, verify the capacity of the NES to reduce or even eliminate these undesired oscillations and to extend the operating speed range of the wing. [less ▲]

Detailed reference viewed: 101 (3 ULg)
Full Text
Peer Reviewed
See detailExperimental demonstration of transient resonance capture in a system of two coupled oscillators with essential stiffness nonlinearity
Kerschen, Gaëtan ULg; McFarland, D. Michael; Kowtko, Jeffrey J. et al

in Journal of Sound & Vibration (2006), 299(4-5), 822-838

The purpose of this paper is to report an experimental study of transient resonance capture that may occur in a system of two coupled oscillators with essential (i.e., nonlinearizable) nonlinearity. It is ... [more ▼]

The purpose of this paper is to report an experimental study of transient resonance capture that may occur in a system of two coupled oscillators with essential (i.e., nonlinearizable) nonlinearity. It is shown that during transient resonance capture the two oscillators are in a state of resonance, the frequency of which varies with time, which leads to targeted nonlinear energy transfer. Further evidence of resonance capture is a non-time-like behavior of the phase difference between the oscillators; this quantity is monitored using the Hilbert transform or the Huang Hilbert transform in the case of multifrequency response signals. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 18 (1 ULg)
Full Text
See detailToward a fundamental understanding of the HHT in nonlinear structural dynamics
Kerschen, Gaëtan ULg; Vakakis, Alexander F.; Lee, Y. S. et al

in 24th International Modal Analysis Conference, Saint-Louis, 2006 (2006)

The Hilbert-Huang transform (HHT) has been shown to be effective for characterizing a wide range of nonstationary signals in terms of elemental components through what has been called the empirical mode ... [more ▼]

The Hilbert-Huang transform (HHT) has been shown to be effective for characterizing a wide range of nonstationary signals in terms of elemental components through what has been called the empirical mode decomposition. The HHT has been utilized extensively despite the absence of a serious analytical foundation, as it provides a concise basis for the analysis of strongly nonlinear systems. In this paper, we attempt to provide the missing link, showing the relationship between the EMD and the slow-flow equations of the system. The slow-flow model is established by performing a partition between slow and fast dynamics using the complexification-averaging technique, and a dynamical system described by slowly-varying amplitudes and phases is obtained. These variables can also be extracted directly from the experimental measurements using the Hilbert transform coupled with the EMD. The comparison between the experimental and analytical results forms the basis of a nonlinear system identification method, termed the slow-flow model identification method, which is demonstrated using numerical examples. [less ▲]

Detailed reference viewed: 27 (1 ULg)
Full Text
Peer Reviewed
See detailIrreversible passive energy transfer in coupled oscillators with essential nonlinearity
Kerschen, Gaëtan ULg; Lee, Young Sup; Vakakis, Alexander F. et al

in SIAM Journal on Applied Mathematics (2006), 66(2), 648-679

We study numerically and analytically the dynamics of passive energy transfer from a damped linear oscillator to an essentially nonlinear end attachment. This transfer is caused by either fundamental or ... [more ▼]

We study numerically and analytically the dynamics of passive energy transfer from a damped linear oscillator to an essentially nonlinear end attachment. This transfer is caused by either fundamental or subharmonic resonance capture, and in some cases is initiated by nonlinear beat phenomena. It is shown that, due to the essential nonlinearity, the end attachment is capable of passively absorbing broadband energy at both high and low frequencies, acting, in essence, as a passive broadband boundary controller. Complicated transitions in the damped dynamics can be interpreted based on the topological structure and bifurcations of the periodic solutions of the underlying undamped system. Moreover, complex resonance capture cascades are numerically encountered when we increase the number of degrees of freedom of the system. The ungrounded essentially nonlinear end attachment discussed in this work can find application in numerous practical settings, including vibration and shock isolation of structures, seismic isolation,. utter suppression, and packaging. [less ▲]

Detailed reference viewed: 30 (6 ULg)
Full Text
See detailTARGETED ENERGY TRANSFERS AND SUPPRESSION OF AEROELASTIC INSTABILITIES
Lee, Young S; Vakakis, Alexander F.; Bergman, Lawrence A. et al

in 2nd International Conf. on NNMs and Localization in Vibrating Systems, Samos, 2006 (2006)

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailTriggering mechanisms of limit cycle oscillations due to aeroelastic instability
Lee, Y. S.; Vakakis, Alexander F.; Bergman, Lawrence A. et al

in Journal of Fluids & Structures (2005), 21

We show that a cascade of resonance captures constitutes the triggering mechanism of limit cycle oscillations (LCOs) due to aeroelastic instability of rigid wings in flow. We consider a two-degree-of ... [more ▼]

We show that a cascade of resonance captures constitutes the triggering mechanism of limit cycle oscillations (LCOs) due to aeroelastic instability of rigid wings in flow. We consider a two-degree-of-freedom (2-dof) wing model in subsonic flow with cubic nonlinear stiffnesses at the support. Under the assumption of quasi-steady aerodynamics, we apply a complexification/averaging technique to express the dynamics of fluid-structure interactions in terms of three fast-frequency components; these are the two linear natural frequencies corresponding to heave and pitch, and a superharmonic at three times the pitch frequency. Bifurcation analysis of the resulting set of modulation equations governing the slow dynamics is carried out via the method of numerical continuation, and reveals the different types of steady state motions realized as parameters vary. It turns out that the LCO triggering mechanism consists of a combination of different dynamic phenomena, taking place at three main stages or regimes: attraction to transient resonance captures (TRCs), escapes from these captures and, finally, entrapments into permanent resonance captures (PRCs). We examine numerically and analytically the dynamics at each of these stages by means of wavelet transform analysis, study of the evolution of appropriately defined phase variables in projections of the phase space of the dynamics, and analysis of instantaneous energy exchanges between the various nonlinear modes involved. The general conclusion is that an initial excitation of the heave mode by the flow acts as the triggering mechanism for the excitation of the pitch mode through nonlinear interactions resulting from the resonance captures and escapes. The eventual excitation of the pitch mode signifies the appearance of an LCO of the in-flow wing. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 35 (2 ULg)
Full Text
Peer Reviewed
See detailEnergy transfers in a system of two coupled oscillators with essential nonlinearity: 1 : 1 resonance manifold and transient bridging orbits
Kerschen, Gaëtan ULg; Vakakis, Alexander F.; Lee, Young S. et al

in Nonlinear Dynamics (2005), 42(3), 283-303

The purpose of this study is to highlight and explain the vigorous energy transfers that may take place in a linear oscillator weakly coupled to an essentially nonlinear attachment, termed a nonlinear ... [more ▼]

The purpose of this study is to highlight and explain the vigorous energy transfers that may take place in a linear oscillator weakly coupled to an essentially nonlinear attachment, termed a nonlinear energy sink. Although these energy exchanges are encountered during the transient dynamics of the damped system, it is shown that the dynamics can be interpreted mainly in terms of the periodic orbits of the underlying Hamiltonian system. To this end, a frequency-energy plot gathering the periodic orbits of the system is constructed which demonstrates that, thanks to a 1:1 resonance capture, energy can be irreversibly and almost completely transferred from the linear oscillator to the nonlinear attachment. Furthermore, it is observed that this nonlinear energy pumping is triggered by the excitation of transient bridging orbits compatible with the nonlinear attachment being initially at rest, a common feature in most practical applications. A parametric study of the energy exchanges is also performed to understand the influence of the parameters of the nonlinear energy sink. Finally, the results of experimental measurements supporting the theoretical developments are discussed. [less ▲]

Detailed reference viewed: 16 (1 ULg)