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Letteratura scientifica selezionata sul tema "Nonlinear interfaces"

Autore: Grafiati

Pubblicato: 13 aprile 2024

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Articoli di riviste sul tema "Nonlinear interfaces"

Savotchenko, S. E. "Nonlinear surface waves propagating along the composite waveguide consisting of self-focusing slab between defocusing media separated by interfaces with nonlinear response". Journal of Nonlinear Optical Physics & Materials 28, n. 04 (dicembre 2019): 1950039. http://dx.doi.org/10.1142/s0218863519500395.

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The model of the composite symmetric waveguide consisting of self-focusing slab between defocusing nonlinear media separated by interfaces characterized by own nonlinearity response is proposed. Two new types of nonlinear surface waves propagating along it with anti-phase amplitude oscillations at interface planes are found. The frequencies of the nonlinear surface waves existing near the interfaces with the nonlinear response only are calculated analytically. The conditions of the surface wave existence are found. The frequencies and localization distances of the surface waves in dependence on nonlinearity waveguide parameters, slab width and interface characteristics are analyzed.

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NASALSKI, W., e D. BURAK. "GAUSSIAN BEAM NONSPECULAR REFLECTION AT A NONLINEAR DEFOCUSING INTERFACE". Journal of Nonlinear Optical Physics & Materials 04, n. 04 (ottobre 1995): 929–42. http://dx.doi.org/10.1142/s0218863595000422.

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Nonspecular reflection of a Gaussian beam impinging an interface between linear and defocusing nonlinear Kerr medium is numerically investigated. A composite nonspecular shift of the reflected beam is documented for both local and nonlocal nonlinear interfaces and the nonspecular character of the beam-interface interaction is clearly shown. In analogy to previous studies on interfaces with focusing and local Kerr nonlinearities, and contrary to the results on interfaces with nonlocal defocusing nonlinearity, no bistability in the parameters of the reflected beam is found. This is also confirmed by numerical simulations based on iterative scheme with a memory effect introduced into the solving procedure.

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VASSILIEV, O. N., e M. G. COTTAM. "OPTICALLY NONLINEAR S-POLARIZED ELECTROMAGNETIC WAVES IN MULTILAYERED SYMMETRIC DIELECTRICS". Surface Review and Letters 07, n. 01n02 (febbraio 2000): 89–102. http://dx.doi.org/10.1142/s0218625x00000129.

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A theory is presented for the nonlinear s-polarized electromagnetic waves in multilayer systems with an arbitrary number of planar interfaces. Each of the individual layers may be characterized by either a linear or a Kerr-type nonlinear dielectric constant, and we examine the coupled nonlinear waves at both linear/nonlinear and nonlinear/nonlinear interfaces. An analysis of the phase trajectories (in terms of an electric field amplitude and its spatial derivative) is employed to enumerate the modes of the system in a systematic manner and to facilitate the derivation of dispersion relations. In particular, numerical examples are given for two-interface systems (for example, a thin film sandwiched between two semi-infinite media) and for periodic superlattices (with effectively infinite interfaces), thereby extending previous calculations.

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Savotchenko, S. E. "Nonlinear surface waves propagating along composite waveguide consisting of nonlinear defocusing media separated by interfaces with nonlinear response". Journal of Nonlinear Optical Physics & Materials 29, n. 01n02 (marzo 2020): 2050002. http://dx.doi.org/10.1142/s0218863520500022.

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The nonlinear surface waves propagating along the ultra-thin-film layers with nonlinear properties separating three nonlinear media layers are considered. The model based on a stationary nonlinear Schrödinger equation with a nonlinear potential modeling the interaction of a wave with the interface in a short-range approximation is proposed. We concentrated on effects induced by the difference of characteristics of the layers and their two interfaces. The surface waves of three types exist in the system considered. The dispersion relations determining the dependence of surface waves energy on interface intensities and medium layer characteristics are obtained and analyzed. The localization energy is calculated in explicit form for many difference cases. The conditions of the wave localization on dependence of the layer and interface characteristics are derived. The surface waves with definite energies in specific cases existing only in the presence of the interface nonlinear response are found. All results are obtained in an explicit analytical form.

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Nouira, Dorra, Davide Tonazzi, Anissa Meziane, Laurent Baillet e Francesco Massi. "Numerical and Experimental Analysis of Nonlinear Vibrational Response due to Pressure-Dependent Interface Stiffness". Lubricants 8, n. 7 (10 luglio 2020): 73. http://dx.doi.org/10.3390/lubricants8070073.

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Modelling interface interaction with wave propagation in a medium is a fundamental requirement for several types of application, such as structural diagnostic and quality control. In order to study the influence of a pressure-dependent interface stiffness on the nonlinear response of contact interfaces, two nonlinear contact laws are investigated. The study consists of a complementary numerical and experimental analysis of nonlinear vibrational responses due to the contact interface. The laws investigated here are based on an interface stiffness model, where the stiffness property is described as a nonlinear function of the nominal contact pressure. The results obtained by the proposed laws are compared with experimental results. The nonlinearity introduced by the interface is highlighted by analysing the second harmonic contribution and the vibrational time response. The analysis emphasizes the dependence of the system response, i.e., fundamental and second harmonic amplitudes and frequencies, on the contact parameters and in particular on contact stiffness. The study shows that the stiffness–pressure trend at lower pressures has a major effect on the nonlinear response of systems with contact interfaces.

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Liang, Yu, Zhigang Zhai, Juchun Ding e Xisheng Luo. "Richtmyer–Meshkov instability on a quasi-single-mode interface". Journal of Fluid Mechanics 872 (13 giugno 2019): 729–51. http://dx.doi.org/10.1017/jfm.2019.416.

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Experiments on Richtmyer–Meshkov instability of quasi-single-mode interfaces are performed. Four quasi-single-mode air/$\text{SF}_{6}$ interfaces with different deviations from the single-mode one are generated by the soap film technique to evaluate the effects of high-order modes on amplitude growth in the linear and weakly nonlinear stages. For each case, two different initial amplitudes are considered to highlight the high-amplitude effect. For the single-mode and saw-tooth interfaces with high initial amplitude, a cavity is observed at the spike head, providing experimental evidence for the previous numerical results for the first time. For the quasi-single-mode interfaces, the fundamental mode is the dominant one such that it determines the amplitude linear growth, and subsequently the impulsive theory gives a reasonable prediction of the experiments by introducing a reduction factor. The discrepancy in linear growth rates between the experiment and the prediction is amplified as the quasi-single-mode interface deviates more severely from the single-mode one. In the weakly nonlinear stage, the nonlinear model valid for a single-mode interface with small amplitude loses efficacy, which indicates that the effects of high-order modes on amplitude growth must be considered. For the saw-tooth interface with small amplitude, the amplitudes of the first three harmonics are extracted from the experiment and compared with the previous theory. The comparison proves that each initial mode develops independently in the linear and weakly nonlinear stages. A nonlinear model proposed by Zhang & Guo (J. Fluid Mech., vol. 786, 2016, pp. 47–61) is then modified by considering the effects of high-order modes. The modified model is proved to be valid in the weakly nonlinear stage even for the cases with high initial amplitude. More high-order modes are needed to match the experiment for the interfaces with a more severe deviation from the single-mode one.

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Савотченко, С. Е. "Нелинейные интерфейсные волны в трехслойной оптической структуре с отличающимися характеристиками слоев и внутренней самофокусировкой". Журнал технической физики 127, n. 7 (2019): 159. http://dx.doi.org/10.21883/os.2019.07.47944.231-18.

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AbstractA model of a trilayered optical structure, the plane-parallel boundary of which possesses its own nonlinear properties, is considered. The inner layer with a finite thickness is an optically transparent medium with Kerr self-focusing nonlinearity, which is in contact with linear half-spaces from the outer surface that are characterized by refractive indices independent of the electric field strength amplitude. Refractive indices in the layer interfaces within infinitely small thicknesses are approximated by the dependence that includes Dirac’s delta function. It is shown that the mathematical formulation of the model boils down to a nonlinear Schrödinger equation with a nonlinear self-consistent potential. It is established that two types of nonlinear localized waves of the electric field strength perturbations can propagate along the layers in the considered trilayered structure. Dispersion relations of the interface waves that allow one to determine the propagation constant and decrements of their spatial attenuation in linear half-spaces as a function of the system parameters are derived. Conditions for localization of a luminous flux along the layer interfaces are analyzed in relation to the sign of the layer parameters. It is shown that the characteristic distance of the field localization linearly depends on the interface nonlinear response parameter. It is established that the characteristic localization distance is shortened in the case of a positive nonlinear response in comparison with the localization length when interfaces do not interact with the field and lengthened in the case of a negative nonlinear response.

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Shrivastava, Shamit, Kevin H. Kang e Matthias F. Schneider. "Collision and annihilation of nonlinear sound waves and action potentials in interfaces". Journal of The Royal Society Interface 15, n. 143 (giugno 2018): 20170803. http://dx.doi.org/10.1098/rsif.2017.0803.

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Nerve impulses, previously proposed as manifestations of nonlinear acoustic pulses localized at the plasma membrane, can annihilate upon collision. However, whether annihilation of acoustic waves at interfaces takes place is unclear. We previously showed the propagation of nonlinear sound waves that propagate as solitary waves above a threshold (super-threshold) excitation in a lipid monolayer near a phase transition. Here we investigate the interaction of these waves. Sound waves were excited mechanically via a piezo cantilever in a lipid monolayer at the air–water interface and their amplitude is reported before and after a collision. The compression amplitude was observed via Förster resonance energy transfer between donor and acceptor dyes, measured at fixed points along the propagation path in the lipid monolayer. We provide direct experimental evidence for the annihilation of two super-threshold interfacial pulses upon head-on collision in a lipid monolayer and conclude that sound waves propagating in a lipid interface can interact linearly, nonlinearly, or annihilate upon collision depending on the state of the system. Thus we show that the main characteristics of nerve impulses, i.e. solitary character, velocity, couplings, all-or-none behaviour, threshold and even annihilation are also demonstrated by nonlinear sound waves in a lipid monolayer, where they follow directly from the thermodynamic principles applied to an interface. As these principles are equally unavoidable in a nerve membrane, our observations strongly suggest that the underlying physical basis of action potentials and the observed nonlinear-pules is identical.

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Sánchez-Curto, Julio, Pedro Chamorro-Posada e Graham S. McDonald. "Dark solitons at nonlinear interfaces". Optics Letters 35, n. 9 (22 aprile 2010): 1347. http://dx.doi.org/10.1364/ol.35.001347.

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Sánchez-Curto, J., P. Chamorro-Posada e G. S. McDonald. "Helmholtz solitons at nonlinear interfaces". Optics Letters 32, n. 9 (3 aprile 2007): 1126. http://dx.doi.org/10.1364/ol.32.001126.

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Tesi sul tema "Nonlinear interfaces"

Poznic, Milan. "Nonlinear Interaction Between Ultrasonic Waves and Cracks and Interfaces". Doctoral thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4604.

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The subject of this thesis is the development of new ultrasound inspection techniques for detection of cracks that are smaller than the wavelength of the inspecting wave and the characterization of cracks in fluid-filled pipes as either surface-breaking or subsurface. The spectrum of the scattered field of a partially closed crack comprises harmonic components not expected to be found in the case of linear scatterers such as pores or inclusions. Paper A presents an experimental investigation into the linear reflection and generation of the 2nd harmonic component following the incidence of an ultrasonic wave onto a dry or water-confining interface formed by elasto-plastic steel-steel surfaces in contact. The results indicate that water has an unexpected effect on the reflection, at low interfacial pressures, suggesting that fluid mediated forces play a role not accounted for in current models. The level of the generation of the 2nd harmonic measured provides support for further development of the technique for detection of dry, partially closed cracks or fluid-filled, nearly open cracks. A theoretical model describing the nonlinear scattering of acoustic waves by surface-breaking cracks with faces in partial contact is presented in Paper B. Both linear and nonlinear response of the crack are shown to be the largest for a SV wave incident on the surface containing the crack at an angle just above the critical angle for longitudinal waves. A method which provides information on whether a fracture is surface-breaking or subsurface has been modelled and its optimal experimental set-up examined in Paper C. The main assumption of the model is that water carried by pressurized pipes infiltrates and fills a surface-breaking crack, while a subsurface crack is dry. The model simulates an inspection in which the modulation technique is employed and the surface hosting the crack is not accessible. A parameter, constructed with signals recorded in backscattering configuration during a modulation cycle, is examined and shown to provide a clear criterion to distinguish subsurface from surface-breaking cracks when a SV wave at 45 degree incidence is employed as a probe. Finally, in Paper D the modulation technique is experimentally tested on steel beams that host surface-breaking fatigue cracks. The method is shown to be a successful tool to distinguish a dry from a fluid-filled crack. Furthermore, it is revealed that the dynamics of the fluid needs to be accounted for in a more accurate simulation tool.
QC 20100906

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Poznić, Milan. "Interaction between ultrasonic waves and nonlinear cracks and interfaces /". Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4087.

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Poznić, Milan. "Nonlinear interaction between ultrasonic waves and cracks and interfaces /". Stockholm : Farkost- och flyg, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4604.

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Shelford, Leigh. "Ultrafast nonlinear optical studies of multilayered thin films and interfaces". Thesis, University of Exeter, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506859.

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Van, Wyck Neal Edward. "MULTIPHOTON SPECTROSCOPY OF THIN FILMS AND SURFACES (NONLINEAR, WAVEGUIDES, INTERFACES)". Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/291294.

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Ojaghlou, Neda. "Adhesion at Solid/Liquid Interfaces". VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6079.

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The adhesion at solid/liquid interface plays a fundamental role in diverse fields and helps explain the structure and physical properties of interfaces, at the atomic scale, for example in catalysis, crystal growth, lubrication, electrochemistry, colloidal system, and in many biological reactions. Unraveling the atomic structure at the solid/liquid interface is, therefore, one of the major challenges facing the surface science today to understand the physical processes in the phenomena such as surface coating, self-cleaning, and oil recovery applications. In this thesis, a variety of theory/computational methods in statistical physics and statistical mechanics are used to improve understanding of water adhesion at solid/liquid interfaces. In here, we addressed two separated, but interconnected problems: First, we consider water adhesion on fiber/surface, responsible for the emergence of droplet residue upon droplet detachment. In this project, we study the mechanism of water droplet detachment and retention of residual water on smooth hydrophilic fibers and surfaces using nonequilibrium molecular dynamics simulations. We investigate how the applied force affects the breakup of a droplet and how the minimal detaching force per unit mass decreases with droplet size. We extract scaling relations that allow extrapolation of our findings to larger length scales that are not directly accessible by molecular models. We find that the volume of the residue on a fiber varies nonmonotonically with the detaching force, reaching the maximal size at an intermediate force and associated detachment time. The strength of this force decreases with the size of the drop, while the maximal residue increases with the droplet volume, V, sub-linearly, in proportion to the V2/3. Second, we address the adhesion on conducting graphene. We improved the graphene model by incorporating the conductivity of graphene sheet using the fluctuating charge technique of Constant Potential Molecular Dynamics (CPMD). We evaluated the wettability by measuring the contact angle of cylindrical water drops on a conducting graphene sheet. We found that the CA of a water droplet on a graphene sheet supported by water is lower than in the absence of water under graphene. Our calculations reveal effective attractions between partial charges of equal sign across the conducting graphene sheet. Attractive correlations are attributed to the formation of the highly localized image charges on carbon atoms between the partially charged sites of water molecules on both sides of graphene. By performing additional computations with nonpolar diiodomethane, we confirm that graphene transmits both polar and dispersive interactions. These findings are important in applications including sensors, fuel cell membranes, water filtration, and graphene-based electrode material to enhance the supercapacitor performance. A challenge for future work concerns dynamic polarization response of wetted graphene at alternating (AC) field condition.

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Lombardi, Giulia. "Unified nonlinear electrical interfaces for hybrid piezoelectric-electromagnetic small-scale harvesting systems". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI101.

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Ce travail de recherche présente des interfaces électroniques non-linéaires pour des systèmes hybrides de récupération d'énergie combinant des transducteurs piézoélectriques et électromagnétiques. Ces systèmes ont reçu un grand intérêt en raison de leur capacité à convertir les vibrations mécaniques en énergie électrique suffisante pour alimenter des capteurs à faible puissance. Afin d'alimenter ces appareils microélectroniques, une fois l'énergie convertie, une extraction efficace et intelligente doit être mise en place avec une unité dédiée. Les interfaces hybrides non-linéaires proposées dans ce travail, visant à inclure autant de parties électroactives que possible dans le même circuit, permettent une augmentation de la puissance de sortie finale des microgénérateurs concernés, ainsi qu'une solution pour obtenir une valeur commune de charge optimale, même si chacun des éléments traités présentent des principes de fonctionnement et des valeurs de charge optimale différents. Une première solution est dérivée du SSHI (Synchronized Switch Harvesting on Inductor) et se base sur la technique de commutation synchronisée. Cette méthode vise à remplacer l'inductance passive dans l'interface SSHI par un système électromagnétique actif, conduisant à une interface de microgénérateurs entièrement actifs et augmentant la puissance de sortie finale. Une deuxième solution est issue de la combinaison des techniques SECE (Synchronous Electric Charge Extraction) et SMFE (Synchronous Magnetic Flux Extraction), respectivement développées pour les systèmes piézoélectriques et électromagnétiques. Son principe de base consiste à transférer l'énergie de l’élément piézoélectrique vers le transducteur électromagnétique, et ensuite à extraire l'énergie du système électromagnétique, préalablement amplifiée par le transfert de charges issues du dispositif piézoélectrique. La stratégie consistant à inclure autant de parties électroactives que possible dans la même interface électrique ouvre de nouvelles possibilités de combiner plusieurs systèmes électroactifs, constituant des récupérateurs d'énergie hybride, sans inclure des étages supplémentaires dans les circuits, ce qui permet de maintenir une relative simplicité sans perte de puissance significative
In this research work, electronic nonlinear interfaces for hybrid energy harvesting systems combining piezoelectric and electromagnetic transducers are presented. Such systems have received great attention due to their ability to detect mechanical vibrations and convert them into electrical energy sufficient to power low-power sensors. In order to supply these microelectronic devices the generated sinusoidal signal needs to be rectified into a constant DC voltage. In other words, once the energy is converted, a proper and smart extraction of such energy needs to be implemented with a dedicated unit. The proposed nonlinear hybrid interfaces developed in this work, aimed at incorporating as much as electroactive parts as possible in the circuit, not only increase the final output power of the involved transducers but also provide a solution for obtaining a common optimal load value, despite dealing with elements singularly presenting different working principles and values of optimal load, without the use of additional load adaptation stages. A first solution is derived from the previously developed SSHI (Synchronized Switch Harvesting on Inductor) and based on the Synchronized Switching technique. This method aims at replacing the passive inductor in the SSHI interface with an active electromagnetic system, leading to an all-active microgenerators interface and increasing the final output power. A second solution is derived from a combination of the SECE (Synchronous Electric Charge Extraction) and SMFE (Synchronous Magnetic Flux Extraction) techniques. Its main principle consists of transferring the energy from the piezoelectric to the electromagnetic transducer and then extracting the boosted energy from the electromagnetic system. The strategy of including as much as electroactive parts within the same electrical interface open many different possibilities of interfacing more than one electroactive system, constituting hybrid energy harvesters, without including extra circuit stages, thus maintaining a relative simplicity without high power losses

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Costard, Rene. "Ultrafast dynamics of phospholipid-water interfaces studied by nonlinear time-resolved vibrational spectroscopy". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2014. http://dx.doi.org/10.18452/16955.

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Geladene Phosphatgruppen sind von wesentlicher Bedeutung für die Hydratisierung von Phospholipiden und DNS. Hydratisierungshüllen spielen eine wichtige Rolle für die Ausbildung und Stabilisierung von Zellmembranen und der DNS-Doppelhelixstruktur. In dieser Arbeit werden elementare Phosphat-Wasser-Wechselwirkungen in einem Phospholidmodellsystem – sogenannten inversen Mizellen - mit variablen Wassergehalt zwischen einem und 16 Wassermolekülen pro Phospholipid untersucht. Die schnellsten Prozesse an den Grenzflächen wie z.B. Phosphat-Wasser-Wasserstoffbrückendynamik und Schwingungsenergieumverteilung finden auf einer Femto- bis Pikosekundenzeitskala statt. Molekulare Schwingungen sind sensitive lokale Sonden für die Struktur und Dynamik. Deshalb ermöglicht Femtosekunden-Schwingungsspektroskope, insbesondere zweidimensionale Infrarotspektroskopie (2D IR) und Pump-Probe-Spektroskopie in einem breiten Spektralbereich, die Dynamik mikroskopischer Phosphat-Wasser-Wechselwirkungen in Echtzeit zu beobachten. Wir zeigen die ersten zweidimensionalen Infrarotspektren von Phosphat-Streckschwingungen, die unabhängig vom Wassergehalt grenzflächensensitive Sonden darstellen. Solche Spektren belegen, dass die schnellsten strukturellen Fluktuationen der Phospholipid-Kopfgruppen auf einer 300-fs Zeitskala ablaufen, wohingegen die Phosphat-Wasser-Wasserstoffbrücken länger als 10 ps bestehen bleiben. Die Schwingungsdynamik intramolekularer Wasserschwingungen, d.h. der OH-Streck- und Biegeschwingung, zeigen, dass sich kleine Wasserpools um die Phosphatgruppen bilden, sobald drei oder mehr Wassermoleküle pro Phospholipid vorliegen. Solche Wasserpools dienen als effiziente Wärmesenken für intramolekulare Schwingungen des Wassers und der Phosphatgruppen.
Charged phosphate groups are the major hydration sites of biomolecules such as phospholipids and DNA. Hydration shells play a key role in the formation and stabilization of cell membranes and the DNA double helix structure. Here, we introduce phospholipid reverse micelles with variable water content (between one and sixteen water molecules per phospholipid) as a model system to study elementary phosphate-water interactions. The fastest processes at phosphate-water interfaces , e.g. hydrogen-bond dynamics and vibrational energy transfer occur on a femto- to picosecond time scale. Since molecular vibrations are sensitive local probes of the structure and dynamics, the use of femtosecond vibrational spectroscopy, in particular two-dimensional infrared spectroscopy (2D IR) and pump-probe spectroscopy in a broad spectral range, allow for the observation of microscopic phosphate-water interactions in real time. We present the first two-dimensional infrared spectra of phosphate stretching vibrations that represent true interfacial probes independent of the hydration level. Such spectra reveal that the fastest structural fluctuations of phospholipid headgroups occur on a 300-fs timescale whereas phosphate-water hydrogen bonds are preserved for >10 ps. Vibrational dynamics of intramolecular water vibrations, i.e., the OH stretching and bending modes show that small water pools around the phosphate groups form when three or more water molecules per phospholipid are present. Such water pools act as efficient heat sinks of excess energy deposited in intramolecular vibrations of water or the phosphate groups.

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RIZZOGLIO, FABIO. "Nonlinear dimensionality reduction for human movement analysis with application to body machine interfaces". Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1038287.

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For my PhD project, I set to explore how a nonlinear dimensionality reduction (DR) technique - autoencoder networks (AEs) - can identify low-dimensional latent manifolds of movement data. The thesis focuses on the application of this technique to body machine interfaces (BoMIs). I begin by comparing nonlinear AEs to Principal Component Analysis (PCA), a linear DR method, in capturing essential information of kinematic signals, including hand gestures and object manipulations, as well as electromyographic signals (EMG) obtained from unconstrained movements of shoulders and arms. AEs exhibited higher performance than PCA in the reconstruction of hand kinematic and EMG data from a latent manifold. Therefore, a non-linear DR method has the potential to provide a more effective coding platform for human-machine interfaces (HMIs). I therefore investigated how the choice of hyperparameters (e.g., type of activation function, number of hidden layers, etc.) affected the shape of the latent manifold, particularly its local curvature, and whether these potential effects were correlated with changes in reconstruction performance. To gain more consistent insights on the structure of the nonlinear latent manifold, I developed a visual tool based on classic concepts of cartography. This display offers a direct and intuitive assessment of the AE’s nonlinear transformation. I was able to demonstrate that the cartographic approach makes the visible structure of the latent manifold stable and independent of the AE’s training parameters. As such, the proposed approach is a step toward defining a unique latent manifold. After analyzing the properties of both linear (PCA) and nonlinear (AE) DR techniques, I focused on their applications within the control-scheme of a BoMI. First, I aimed at providing BoMI users with the possibility to switch seamlessly between movement and EMG control. Such approach is essential to utilize the BoMI as a therapeutic tool for promoting recovery of muscle control after neurological injury. In the clinical context it is essential to adapt the operation of the BoMI to the evolving state of its users. My guiding hypothesis for this purpose is that the operation of the interface is facilitated if the BoMI forward map is updated online to match the evolving latent manifold of the user’s motions. Results show that this adaptive approach increased the representational efficiency of the interface and significantly improved users’ task-related performance. As an extension of the application of AE-based BoMI, I developed a non-linear BoMI designed to control an assistive 4D virtual robotic manipulator and tested the interface on a cohort of unimpaired participants, who successfully acquired a high level of robot control. To conclude, I investigated whether AEs can represent and estimate motor learning during the operation of a BoMI. This final study demonstrates that in fact this nonlinear method is effective to accurately track users’ learning process.

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Aanensen, Nina Sasaki. "Nonlinear Laser-induced Deformations and Forces at Liquid-Liquid Interfaces near the critical Point". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14264.

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The theory of laser-induced liquid-liquid interface deformation has been presented and used to derive a differential equation describing the shape of the deformation. The differential equation has been investigated and solved numerically, and the results have been compared to the experimental results of the Bordeaux group. A model describing the maximum depth of the deformation based on the theory of a sphere in an electric field has also been investigated.The deformations from the numerical solutions of the differential equation are too wide compared to the experimental results. The shoulder-shape that has been observed in the experiments is not present in the numerical solutions. There is reason to believe that the differential equation may be too simple in order to describe the liquid-liquid interface deformation for nonlinear cases. There may be thermal effects that changes the liquid properties due to local temperature variations induced by the laser, causing the liquid parameters to change along the deformation.The model used to estimate the deformation depth does not give reasonable results, as it leads to a deformation that is more than 100 times larger than what is observed in the corresponding experiments. The assumptions made for this model may not be valid, and a discussion on what should be done in order to improve the model is included in this text.

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Più fonti

Libri sul tema "Nonlinear interfaces"

Whitfield, Troy W. Nonlinear optics and liquid structures of interfaces. Ottawa: National Library of Canada, 1994.

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Center, NASA Glenn Research, a cura di. Nonlinear dynamics of a diffusing interface. [Cleveland, Ohio]: National Aeronautics and Space Administration, Glenn Research Center, 2001.

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J, McGilp, Weaire D. L e Patterson C. H. 1961-, a cura di. Epioptics: Linear and nonlinear optical spectroscopy of surfaces and interfaces. Berlin: Springer, 1995.

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Colinet, P. Pattern formation at interfaces. Wien: Springer, 2010.

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Dynamics of internal layers and diffusive interfaces. Philadelphia, Pa: Society for Industrial and Applied Mathematics, 1988.

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United States. National Aeronautics and Space Administration., a cura di. Interface technology for geometrically nonlinear analysis of multiple connected subdomains. [Reston, VA?]: American Institute of Aeronautics and Astronautics, 1997.

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Shabat, Mohammed Musa Ramadan. Linear and nonlinear electro-magnetic waves at magnetic and non-magnetic interfaces. Salford: University of Salford, 1990.

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Nelson, Cory A. Probing surfaces and interfaces by nonlinear optical spectroscopy with time, energy, and phase resolution. [New York, N.Y.?]: [publisher not identified], 2015.

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Alicante, Raquel. Photoinduced Modifications of the Nonlinear Optical Response in Liquid Crystalline Azopolymers. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013.

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Capitoli di libri sul tema "Nonlinear interfaces"

Nepomnyashchy, Alexander A. "Nonlinear dynamics of fronts". In Pattern Formation at Interfaces, 57–103. Vienna: Springer Vienna, 2010. http://dx.doi.org/10.1007/978-3-7091-0125-4_2.

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Mills, D. L. "Nonlinear Optical Interactions at Surfaces and Interfaces". In Nonlinear Optics, 155–90. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-58937-9_8.

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Stegeman, George I., e Colin T. Seaton. "Nonlinear Surface Polaritons". In Dynamical Phenomena at Surfaces, Interfaces and Superlattices, 266–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-82535-4_26.

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Kaplan, A. E., P. W. Smith e W. J. Tomlinson. "Nonlinear Waves and Switching Effects at Nonlinear Interfaces". In Nonlinear Waves in Solid State Physics, 93–111. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4684-5898-5_3.

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Sakawa, Masatoshi. "Fuzzy Multiobjective Nonlinear Programming". In Operations Research/Computer Science Interfaces Series, 153–68. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/978-1-4615-1519-7_8.

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Sakawa, Masatoshi. "Genetic Algorithms for Nonlinear Programming". In Operations Research/Computer Science Interfaces Series, 133–51. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/978-1-4615-1519-7_7.

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Schmitt-Rink, Stefan. "Ultrafast Nonlinear Optical Phenomena in Semiconductor Quantum Wells". In Interfaces, Quantum Wells, and Superlattices, 211–26. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-1045-7_12.

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Lawal, I., S. Shah, M. Gonzalez-Madrid, T. Hu, C. W. Schwingshackl e M. R. W. Brake. "The Effect of Non-Flat Interfaces On System Dynamics". In Nonlinear Dynamics, Volume 1, 187–97. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-74280-9_21.

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Lemaitre, Jean. "Conditions of Crack Arrest by Interfaces". In IUTAM Symposium on Nonlinear Analysis of Fracture, 125–33. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5642-4_12.

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Dodson, Jacob C., Janet Wolfson, Jason R. Foley e Daniel J. Inman. "Transmission of Guided Waves Across Prestressed Interfaces". In Topics in Nonlinear Dynamics, Volume 3, 83–94. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-2416-1_8.

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Atti di convegni sul tema "Nonlinear interfaces"

Baron, Alexandre, Thang B. Hoang, Chao Fang, Stéphane Larouche, Daniel J. Gauthier, Maiken H. Mikkelsen e David R. Smith. "Nonlinear Metal/Dielectric Plasmonic Interfaces". In Nonlinear Optics. Washington, D.C.: OSA, 2015. http://dx.doi.org/10.1364/nlo.2015.ntu2b.2.

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Sánchez-Curto, Julio, Pedro Chamorro-Posada e Graham S. McDonald. "Helmholtz dark solitons at nonlinear defocusing interfaces". In Nonlinear Photonics. Washington, D.C.: OSA, 2010. http://dx.doi.org/10.1364/np.2010.ntuc22.

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Wen, Yu-Chieh, Xiaofan Xu, Shuai Zha, Yuen Ron Shen e Chuanshan Tian. "Structure of Water Interfaces Studied by Phase Sensitive Sum Frequency Vibrational Spectroscopy". In Nonlinear Optics. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/nlo.2013.nth2b.3.

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McCoy, E. A., J. M. Christian, G. S. McDonald, J. Sánchez-Curto e P. Chamorro-Posada. "Refraction and Goos-Hänchen Shifts of Spatial Solitons at Cubic-Quintic Interfaces". In Nonlinear Optics. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/nlo.2013.nw2a.3.

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Potma, Eric O., e John Kenison. "Coherent Raman scattering at interfaces (Conference Presentation)". In Ultrafast Nonlinear Imaging and Spectroscopy VI, a cura di Zhiwen Liu, Demetri Psaltis e Kebin Shi. SPIE, 2018. http://dx.doi.org/10.1117/12.2322636.

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Xiong, Wei, Jennifer E. Laaser, Peerasak Paoprasert, Ryan A. Franking, Robert J. Hamers, Padma Gopalan e Martin T. Zanni. "Nonlinear spectroscopy on charge transfer interfaces". In SPIE NanoScience + Engineering. SPIE, 2011. http://dx.doi.org/10.1117/12.897551.

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Boardman, Allan, Neil King, Yuriy Rapoport e Larry Velasco. "Nonlinear gyrotropic guided waves at negatively refracting interfaces". In Nonlinear Guided Waves and Their Applications. Washington, D.C.: OSA, 2005. http://dx.doi.org/10.1364/nlgw.2005.thb19.

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Vicente, Rafael A., Guilherme H. Oliveira, Pablo S. Fernández e Rene Nome. "Low-frequency stimulated Raman spectroscopy measurements at electrochemical interfaces". In Ultrafast Nonlinear Imaging and Spectroscopy VIII, a cura di Zhiwen Liu, Demetri Psaltis e Kebin Shi. SPIE, 2020. http://dx.doi.org/10.1117/12.2567098.

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Ferrando, A., C. Milian, D. Ceballos e D. V. Skryabin. "Stability of soliplasmon excitations at metal/dielectric interfaces". In 2011 IEEE International Workshop "Nonlinear Photonics" (NLP). IEEE, 2011. http://dx.doi.org/10.1109/nlp.2011.6102645.

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HÄRTERICH, J., e K. SAKAMOTO. "INTERFACES DRIVEN BY REACTION, DIFFUSION AND CONVECTION". In Proceedings of the International Conference on Nonlinear Analysis. WORLD SCIENTIFIC, 2008. http://dx.doi.org/10.1142/9789812709257_0015.

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Rapporti di organizzazioni sul tema "Nonlinear interfaces"

Benderskii, Alexander V. Nonlinear Spectroscopies of Nanostructured Surfaces and Interfaces. Fort Belvoir, VA: Defense Technical Information Center, novembre 2009. http://dx.doi.org/10.21236/ada563142.

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Miranda, Paulo B. Nonlinear vibrational spectroscopy of surfactants at liquid interfaces. Office of Scientific and Technical Information (OSTI), dicembre 1998. http://dx.doi.org/10.2172/6502.

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Richmond, Geraldine L., e Stephen D. Kevan. Nonlinear Studies of Surface and Interfaces of Advanced Semiconductor Materials. Fort Belvoir, VA: Defense Technical Information Center, luglio 1992. http://dx.doi.org/10.21236/ada253365.

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Richmond, Geraldine, e Stephen Kevan. Nonlinear Studies of Surfaces and Interfaces of Advanced Semiconductor Materials. Fort Belvoir, VA: Defense Technical Information Center, luglio 1992. http://dx.doi.org/10.21236/ada254324.

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Jacobs-O'Malley, Laura Diane, e John Hofer. Nonlinear Feature Extraction and Energy Dissipation of Foam/Metal Interfaces. Office of Scientific and Technical Information (OSTI), aprile 2017. http://dx.doi.org/10.2172/1595879.

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Geiger, Franz. Uranium(IV) Interaction with Aqueous/Solid Interfaces Studied by Nonlinear Optics. Office of Scientific and Technical Information (OSTI), marzo 2015. http://dx.doi.org/10.2172/1176883.

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Miles, Aaron R. The Effect of Initial Conditions on the Nonlinear Evolution of Perturbed Interfaces Driven by Strong Blast Waves. Office of Scientific and Technical Information (OSTI), gennaio 2004. http://dx.doi.org/10.2172/15014148.

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Furtak, T. E. Vibrational spectroscopy of buried interfaces using nonlinear optics. Final technical report, July 7, 1986--February 29, 1996. Office of Scientific and Technical Information (OSTI), maggio 1996. http://dx.doi.org/10.2172/286295.

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S. Enguehard e B. Hatfield. Web-interfaced Nonlinear Optical Waveguide and Photonic Crystal Simulator. Office of Scientific and Technical Information (OSTI), giugno 2002. http://dx.doi.org/10.2172/936601.

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Abrahamson, Norman, e Zeynep Gülerce. Regionalized Ground-Motion Models for Subduction Earthquakes Based on the NGA-SUB Database. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, dicembre 2020. http://dx.doi.org/10.55461/ssxe9861.

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Abstract (sommario):

A set of global and region-specific ground-motion models (GMMs) for subduction zone earthquakes is developed based on the database compiled by the Pacific Earthquake Engineering Research Center (PEER) Next Generation Attenuation - Subduction (NGA-SUB) project. The subset of the NGA-SUB database used to develop the GMMs includes 3914 recordings from 113 subduction interface earthquakes with magnitudes varying between 5 and 9.2 and 4850 recordings from 89 intraslab events with magnitudes varying between 5 and 7.8. Recordings in the back-arc region are excluded, except for the Cascadia region. The functional form of the model accommodates the differences in the magnitude, distance, and depth scaling for interface and intraslab earthquakes. The magnitude scaling and geometrical spreading terms of the global model are used for all regions, with the exception of the Taiwan region which has a region-specific geometrical spreading scaling. Region-specific terms are included for the large distance (linear R) scaling, VS30 scaling, Z2.5 scaling, and the constant term. The nonlinear site amplification factors used in Abrahamson et al. (2016) subduction GMM are adopted. The between-event standard deviation piece of the aleatory variability model is region and distance independent; whereas, the within-event standard deviations are both region and distance dependent. Region-specific GMMs are developed for seven regions: Alaska, Cascadia, Central America, Japan, New Zealand, South America, and Taiwan. These region-specific GMMs are judged to be applicable to sites in the fore-arc region at distances up to 500 km, magnitudes of 5.0 to 9.5, and periods from 0 to 10 sec. For the Cascadia region, the region-specific model is applicable to distances of 800 km including the back-arc region. For the sites that are not in one of the seven regions, the global GMM combined with the epistemic uncertainty computed from the range of the regional GMMs should be used.

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