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Concept

Signal en dents de scie

Publications associées (24)

Optothermal shaping of lamb waves with square and spiral phase fronts

Romain Christophe Rémy Fleury, Aleksi Antoine Bossart, Janez Rus

We introduce a Lamb-wave medium with tunable propagation velocities, which are controlled by a two-dimensional heating pattern produced by a laser beam. We utilized it to demonstrate that waves in an appropriately designed medium can propagate in the form ...

2024

Generalised Kerr Microcomb Physics in Synchronously Driven Systems

Miles Henry Anderson

In this thesis, the generation of microcombs under complex, non-trivial, and/or higher-order cavity conditions is explored, both in theory & simulation, and in practical experimentation. Pulse-driving of microresonators is investigated for the generation ...

EPFL2023

Step detection in power system waveforms for improved RoCoF and frequency estimation

Mario Paolone, Asja Derviskadic, Guglielmo Frigo, Alexandra Cameron Karpilow

The evaluation of the signal frequency and Rate of Change of Frequency (RoCoF) from voltage or current waveforms is used for critical grid control, monitoring and protection applications. However, when step changes in the amplitude or phase of the signal o ...

Elsevier2022

Zero dispersion Kerr solitons in optical microresonators

Tobias Kippenberg, Junqiu Liu, Wenle Weng, Miles Henry Anderson, Alexey Tikan

Solitons are shape preserving waveforms that are ubiquitous across nonlinear dynamical systems from BEC to hydrodynamics, and fall into two separate classes: bright solitons existing in anomalous group velocity dispersion, and switching waves forming 'dark ...

Nature Research2022

Quantum interference effects of out-of-plane confinement on two-dimensional electron systems in oxides

Emmanouil Frantzeskakis, Ji Dai

It was recently discovered that a conductive, metallic state is formed on the surface of some insulating oxides. First observed on SrTiO3 (001), it was then found in other compounds as diverse as anatase TiO2, KTaO3, BaTiO3, ZnO, and also on different surf ...

2020

Discrete Time Analysis of Phase Detector Linear Range Extension in Sub-Sampling PLL

Yusuf Leblebici, Duygu Kostak

The discrete time analysis of the phase detector linear range extension in the first and the second order sub sampling phase-locked loop (SSPLL) is presented. The aim is to understand how much the stability and the pull-in range are affected by the linear ...

IEEE2020

Comprehensive Spectral Analysis of PWM Waveforms With Compensated DC link Oscillations

Drazen Dujic, Stefan Milovanovic

In the available literature, including reference books on the topic, the spectral analysis of voltage waveforms obtained through the use of pulse-width modulation relies on the assumption of an ideally flat voltage across the DC link of a considered switch ...

2020

A stick-slip/inchworm hybrid rotary piezo motor based on a symmetric triangular driving mechanism

Dongdong Zheng

A stick-slip/inchworm hybrid rotary piezomotor based on a symmetric triangular driving mechanism, which can simultaneously achieve the benefits of both stick-slip and inchworm motors, was reported in this letter. It is based on the principle of stick-slip ...

2019

Local control theory for superconducting qubits

Ivano Tavernelli, Sara Bonella

In this work, we develop a method to design control pulses for fixed-frequency superconducting qubits coupled via tunable couplers based on local control theory, an approach commonly employed to steer chemical reactions. Local control theory provides an al ...

AMER PHYSICAL SOC2019

Electromagnetic Fields Associated With the M‐Component Mode of Charge Transfer

Marcos Rubinstein, Mohammad Azadifar, Davide Pavanello, Lixia He

In upward flashes, charge transfer to ground largely takes place during the initial continuous current (ICC) and its superimposed pulses (ICC pulses). ICC pulses can be associated with either M-component or leader/return-stroke like modes of charge transfe ...

2019

Method for estimating synchrophasors during static and dynamic conditions

Mario Paolone, Asja Derviskadic, Paolo Romano

A method for performing synchrophasor estimation of an input signal, whereby the input signal is a sinusoidal power system voltage or current signal, comprising: a. Periodic sampling of a continuous time-domain waveform, consisting of a power system voltag ...

2018

An Analysis of Current and Electric Field Pulses Associated With Upward Negative Lightning Flashes Initiated from the Säntis Tower

Marcos Rubinstein, Davide Pavanello, Mohammad Azadifar, Lixia He

We present a study on the characteristics of current and electric field pulses associated with upward lightning flashes initiated from the instrumented Säntis Tower in Switzerland. The electric field was measured 15 km from the tower. Upward flashes always ...

2018

Peta-pico-Voltron: An open-source high voltage power supply

Samuel Rosset, Samuel Schlatter

We present the design (hardware + software) of “Peta-pico-Voltron”, a low-current high voltage power supply for electrostatic actuators. Developed primarily for dielectric elastomer actuators, it offers a low-cost solution to generate user controllable vol ...

2018

High sensitivity field asymmetric ion mobility spectrometer

Jürgen Brugger, Giovanni Boero, Philippe Marmillod, Mario Andres Chavarria Varon, Alessandro Valentino Matheoud

A high sensitivity field asymmetric ion mobility spectrometer (FAIMS) was designed, fabricated, and tested. The main components of the system are a 10.6 eV UV photoionization source, an ion filter driven by a high voltage/high frequency n-MOS inverter circ ...

American Institute of Physics2017

An experimentalist's guide to the matrix element in angle resolved photoemission

Simon Karl Moser

Angle resolved photoemission spectroscopy (ARPES) is commonly known as a powerful probe of the one-electron removal spectral function in ordered solid state. With increasing efficiency of light sources and spectrometers, experiments over a wide range of em ...

Elsevier Science Bv2017

Simple predictive electron transport models applied to sawtoothing plasmas

Olivier Sauter, Timothy Goodman, Antoine Pierre Emmanuel Alexis Merle, Doohyun Kim

In this work, we introduce two simple transport models to evaluate the time evolution of electron temperature and density profiles during sawtooth cycles (i.e. over a sawtooth period time-scale). Since the aim of these simulations is to estimate reliable p ...

Plasma Physics and Controled Fusion2016

The merits of ion cyclotron heating schemes for sawtooth control in tokamak plasmas

Jonathan Graves, Jonathan Marc Philippe Faustin

JET experiments have compared the efficacy of low-and high field side ion cyclotron resonance heating (ICRH) as an actuator to deliberately minimise the sawtooth period. It is found that low-field side ICRH with low minority concentration is optimal for sa ...

Cambridge University Press2015

On Minimal Trajectories for Mobile Sampling of Bandlimited Fields

Martin Vetterli, Jayakrishnan Unnikrishnan

We study the design of sampling trajectories for stable sampling and the reconstruction of bandlimited spatial fields using mobile sensors. The spectrum is assumed to be a symmetric convex set. As a performance metric we use the path density of the set of ...

Elsevier2015

A Methodology for Global Sensitivity Analysis for Time-Dependent Code Output Applied to Reflood Simulation in TRACE

Andreas Pautz, Damar Canggih Wicaksono

Understanding properly the impact of model parameters and their interactions on the predictions is required for an appropriate model assessment. For simulation of reflooding following a LOCA, this requirement is justified because the important parameters a ...

2015

Fast prediction and evaluation of gravitational waveforms using surrogate models

Jan Sickmann Hesthaven

We propose a solution to the problem of quickly and accurately predicting gravitational waveforms within any given physical model. The method is relevant for both real-time applications and in more traditional scenarios where the generation of waveforms us ...

American Physical Society2014