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Concept

Dissipation factor

Publications associées (28)

Highly dispersed nanomaterials in polymer matrix via aerosol-jet-based multi-material 3D printing

Michael James Henry Smith

Polymer-based nanocomposites emerged in the 1960s as a groundbreaking approach to advanced materials. By incorporating robust, durable, and multifunctional nanomaterials into a polymer matrix, the performance of nanocomposites has significantly surpassed t ...

Elsevier2024

Nanomechanical resonators with low dissipation for quantum optomechanics

Alberto Beccari

Fields of technology as diverse as microwave filter construction, characterization of material interfaces with atomic precision, and detection of gravitational waves from astronomical sources employ mechanical resonators at their core. The utility of mecha ...

EPFL2023

Toward Metantennas: Metamaterial-Based Antennas for Wireless Communications

Yuanyan Su

Antennas have historically been the most common electromagnetic (EM) technology for wireless communication systems. Antenna as hardware is entirely dependent on the EM properties of the materials used, mostly related to the permittivity and permeability. I ...

Ieee-Inst Electrical Electronics Engineers Inc2023

Perimeter Modes of Nanomechanical Resonators Exhibit Quality Factors Exceeding 10(9) at Room Temperature

Tobias Kippenberg, Guanhao Huang, Nils Johan Engelsen, Sergey Fedorov, Alberto Beccari, Amirali Arabmoheghi

Systems with low mechanical dissipation are extensively used in precision measurements such as gravitational wave detection, atomic force microscopy, and quantum control of mechanical oscillators via optomechanics and electromechanics. The mechanical quali ...

American Physical Society2022

Hierarchical tensile structures with ultralow mechanical dissipation

Tobias Kippenberg, Nils Johan Engelsen, Sergey Fedorov, Alberto Beccari, Amirali Arabmoheghi

Structural hierarchy is found in myriad biological systems and has improved man-made structures ranging from the Eiffel tower to optical cavities. In mechanical resonators whose rigidity is provided by static tension, structural hierarchy can reduce the di ...

Nature Portfolio2022

Reduced material loss in thin-film lithium niobate waveguides

Tobias Kippenberg, Guanhao Huang, Mikhail Churaev, Zihan Li

Thin-film lithium niobate has shown promise for scalable applications ranging from single-photon sources to high-bandwidth data communication systems. Realization of the next generation high-performance classical and quantum devices, however, requires much ...

AIP Publishing2022

Transient Elastomers with High Dielectric Permittivity for Actuators, Sensors, and Beyond

Holger Frauenrath, Yauhen Sheima

Dielectric elastomers (DEs) are key materials in actuators, sensors, energy harvesters, and stretchable electronics. These devices find applications in important emerging fields such as personalized medicine, renewable energy, and soft robotics. However, e ...

AMER CHEMICAL SOC2022

Ultra low quantum decoherence nano-optomechanical systems

Mohammadjafar Bereyhi

Thermal motion of a room-temperature mechanical resonator typically dominates the quantum backaction of its position measurement. This is a longstanding barrier for exploring cavity optomechanics at room temperature. In order to enter the quantum regime of ...

EPFL2022

Ag-doped As-S-Se chalcogenide glasses: a correlative study of structural and dielectrical properties

Mirjana Dimitrievska

This work is focused on investigating the effect of Ag doping on the dielectric and structural properties of the As-S-Se glass system and their suitability for potential applications in optoelectronics, such as electronic and switching components. A series ...

SPRINGER2021

Second harmonic generation in glass-based metasurfaces using tailored surface lattice resonances

Olivier Martin, Fabien Sorin, Jérémy Butet, Wei Yan, Kuang-Yu Yang, Dang Tùng Nguyen, Andreas Leber, Chaoqun Dong

Dielectric metasurfaces have shown prominent applications in nonlinear optics due to strong field enhancement and low dissipation losses at the nanoscale. Chalcogenide glasses are one of the promising materials for the observation of nonlinear effects than ...

2021

Hydrodynamic dead zone in multiphase geophysical flows impacting a rigid obstacle

Xingyue Li

When a gravity-driven solid-fluid mixture, such as those in geophysical flows, hits a wall-like rigid obstacle, a metastable jammed zone called hydrodynamic dead zone (HDZ) may emerge. The unjammed-jammed transition of HDZ, controlled by the intricate inte ...

2021

Coss Loss Tangent of Field-Effect Transistors: Generalizing High-Frequency Soft-Switching Losses

Elison de Nazareth Matioli, Luca Nela, Armin Jafari, Mohammad Samizadeh Nikooytabalvandani, Palliyage Srilak Nirmana Perera

The dissipated energy (Ediss) related to the resonant charging/discharging of a transistor output capacitance, becomes a dominant loss factor for power converters operating in the MHz range. A recent work has introduced a small-signal measurement method to ...

2020

Small-Signal Approach for Precise Evaluation of Gate Losses in Soft-Switched Wide-Band-Gap Transistors

Elison de Nazareth Matioli, Armin Jafari, Palliyage Srilak Nirmana Perera

High-frequency switching is favorable for fast transient response, small size of passive components and superior power density, especially in soft-switching topologies. At high frequencies, power dissipation due to consecutive charging/discharging of gate ...

IEEE2020

Mechanical resonators with high dissipation dilution in precision and quantum measurements

Sergey Fedorov

Position measurements of mechanical oscillators underpin experiments spanning from applied nanoscale sensing to endeavors aiming to resolve open fundamental problems of modern physics. Sufficiently precise position measurements are also used for engineerin ...

EPFL2021

Properties of convex optimal power flow model based on power loss relaxation

Mario Paolone, Zhao Yuan

We derive the branch ampacity constraint associated to power losses for the convex optimal power flow (OPF) model based on the branch flow formulation. The branch ampacity constraint derivation is motivated by the physical interpretation of the transmissio ...

Elsevier2020

AC Loss Measurement of the DEMO TF React&Wind Conductor Prototype No. 2

Pierluigi Bruzzone, Boris Stepanov, Kamil Sedlák

The EUROfusion DEMO is being designed as the fusion machine to be built after ITER. During the preconceptual phase, several design options are investigated by theoretical analyses as well as tests on newly developed conductor prototypes. One design option ...

IEEE Institute of Electrical and Electronics Engineers2020

Electrical energy generated by silicone elastomers filled with nanospring- carbon- nanotubes

Frank Nüesch

Dielectric elastomer generators (DEGs) are flexible capacitors that convert mechanical into electrical energy. They rely on an external voltage source to charge the capacitor during each operation cycle. An alternative to this is an autonomous DEG which op ...

Royal Society of Chemistry2019

Exploration of Negative Capacitance Devices and Technologies

Ali Saeidi

Conventional device scaling has been the main guiding principle of the MOS device engineering over these past years. However, this aggressive scaling would be eventually limited due to the inability to remove the heat generated by MOSFET devices. The power ...

EPFL2019

Unsteady Flow Numerical Simulations on Internal Energy Dissipation for a Low-Head Centrifugal Pump at Part-Load Operating Conditions

François Avellan, Xiaoran Zhao

Dredge pumps are usually operated at part-load conditions, in which the low-solidity centrifugal impeller could experience large internal energy dissipation, related to flow separation and vortices. In this study, SST k- and SAS-SST turbulence models were ...

2019

Multimode microwave circuit optomechanics as a platform to study coupled quantum harmonic oscillators

Nathan Rafaël Bernier

Harmonic oscillators might be one of the most fundamental entities described by physics. Yet they stay relevant in recent research. The topological properties associated with exceptional points that can occur when two modes interact have generated much int ...

EPFL2019