Concept

Quartz (minéral)

Publications associées (75)

Phase Transformation-Induced Interfacial Debonding of Silica Inclusions in Iron

Andreas Mortensen, David Hernandez Escobar, Julie Nathalie S Gheysen, Alejandra Inés Slagter

We document that in unstressed, undeformed, samples of pure iron containing silica inclusions precipitated by melt deoxidation, the iron matrix and a small fraction of the silica inclusions are locally separated at room temperature by a void. Thermal cycli ...

New York2023

Piezoelectric thin films on Quartz substrate

David Yann Niederhauser

The aim of this project is to deposit a thin film of aluminum nitride (AlN) or aluminum scandium nitride (AlScN) on a quartz substrate showing good piezoelectric properties for use in tuning fork oscillators. Quartz oscillators are commonly used in various ...

2023

Natural aging and vacancy trapping in Al-6xxx

William Curtin, Michele Ceriotti

Undesirable natural aging (NA) in Al-6xxx delays subsequent artificial aging (AA) but the size, composition, and evolution of clustering are challenging to measure. Here, atomistic details of early-stage clustering in Al-1% Mg-0.6%Si during NA are studied ...

Heidelberg2023

Excitonic devices with van der Waals heterostructures: valleytronics meets twistronics

Andras Kis, Fedele Tagarelli, Ahmet Avsar, Alberto Ciarrocchi

2D semiconducting transition metal dichalcogenides comprise an emerging class of materials with distinct properties, including large exciton binding energies that reach hundreds of millielectronvolts and valley-contrasting physics. Thanks to the van der Wa ...

2022

Effect of different ions on dissolution rates of silica and feldspars at high pH

Karen Scrivener, Barbara Lothenbach, Mahsa Bagheri, Mahdieh Shakoorioskooie

The dissolution kinetics of silica-containing minerals in aggregates influences strongly the process of ASR in concrete. In this paper, the effect of different ions on the dissolution rates of SiO2 (amorphous and quartz) and feldspars at high pH values was ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Abnormal temperature dependent elastic properties of fused silica irradiated by ultrafast lasers

Yves Bellouard, Pieter Vlugter

Materials with thermal-invariant elastic properties are of interest for resonant device frequency and dimensional stability of precision devices. Here, we demonstrate that the temperature coefficient of elasticity (TCE) of amorphous silica can be locally r ...

2022

Effect of femtosecond laser-induced high pressure on fused silica polymorphism

Arunkrishnan Radhakrishnan

High-pressure studies in silica are of great interest to earth and planetary sciences. Highpressure phases are rarely found in nature as a result of shock events like meteorite impacts orvolcanic events in nature. Recreating these phases remains a challeng ...

EPFL2022

FEM simulation: Thermal properties of thin film quartz and silicon resonators

This semester project aimed at simulating two approaches for low temperature dependence of resonance frequency of resonators. The first one consists in using AT-cut quartz as the resonator’s material. The AT-cut quartz wafers are made using a 35° angle wit ...

2021

Direct Visualization of Atomic-Scale Heterogeneous Structure Dynamics in MnO2 Nanowires

Kangning Zhao, Xin Peng, Yuyang Zhang

Manganese oxides are attracting great interest owing to their rich polymorphism and multiple valent states, which give rise to a wide range of applications in catalysis, capacitors, ion batteries, and so forth. Most of their functionalities are connected t ...

AMER CHEMICAL SOC2021

Inorganic and Metal-Organic Heterogeneous Catalysts for Hydrogen Energy Applications

Fatma Pelin Uran

The main focus of this thesis is the exploration of inorganic and metal-organic heterogeneous catalysts for hydrogen (H2) energy applications. In particular, we investigated metal nanoparticles (NPs) and metal-organic frameworks (MOFs) for their employment ...

EPFL2021

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