Publications associées à Effet isotopique cinétique

Diagenetic isotope exchange in biocalcites for paleoclimate reconstruction

The oxygen isotope compositions of fossil biocalcites, such as foraminifera, bivalves, brachiopods, and belemnites have allowed for reconstructions of sea surface and deep ocean temperatures throughout the Phanerozoic and constitute the most important reco ...

EPFL2024

Probing Catalytic Sites and Adsorbate Spillover on Ultrathin FeO2-x Film on Ir(111) during CO Oxidation

Harald Brune, Hao Yin, Wei Fang

The spatially resolved identification of active sites on the heterogeneous catalyst surface is an essential step toward directly visualizing a catalytic reaction with atomic scale. To date, ferrous centers on platinum group metals have shown promising pote ...

Amer Chemical Soc2024

Organic matters, but inorganic matters too: column examination of elevated mercury sorption on low organic matter aquifer material using concentrations and stable isotope ratios

Lorenz Schwab

Sorption of mercury (Hg) in soils is suggested to be predominantly associated with organic matter (OM). However, there is a growing collection of research that suggests that clay minerals and oxides are also important solid phases for the sorption of solu ...

2024

Asymmetric Synthesis of Enantioenriched Zigzag-Type Molecular Belts by Kinetic Resolution and Subsequent Transformations

Jieping Zhu, Shuo Tong

Asymmetric synthesis of enantioenriched zigzag-type molecular belts featuring copper/H8-binaphthol-catalyzed kinetic resolution of a resorcinarene derivative and subsequent transformations was developed. The acquired rigid and C4-symmetric belt exhibited r ...

2023

Mercury Isotope Fractionation during Dark Abiotic Reduction of Hg(II) by Dissolved, Surface-Bound, and Structural Fe(II)

Lorenz Schwab

Stable mercury (Hg) isotope ratios are an emerging tracer for biogeochemical transformations in environmental systems, but their application requires knowledge of isotopic enrichment factors for individual processes. We investigated Hg isotope fractionatio ...

Amer Chemical Soc2023

The role of isotope mass and transport for H-mode access in tritium containing plasmas at JET with ITER-like wall

Henri Weisen, Haomin Sun, Javier García Hernández, Marco Wischmeier, Nicola Vianello, Mikhail Maslov

The required heating power, P-LH, to access the high confinement regime (H-mode) in tritium containing plasmas is investigated in JET with ITER-like wall at a toroidal magnetic field of B-t = 1.8 T and a plasma current of I-p = 1.7 MA. PLH, also referred t ...

IOP Publishing Ltd2023

Inferring free-energy barriers and kinetic rates from molecular dynamics via underdamped Langevin models

Sara Bonella, Fabio Pietrucci, David Daniel Girardier

Rare events include many of the most interesting transformation processes in condensed matter, from phase transitions to biomolecular conformational changes to chemical reactions. Access to the corresponding mechanisms, free-energy landscapes and kinetic r ...

Aip Publishing2023

Organocatalytic Enantioselective Pictet–Spengler Reaction of α‐Ketoesters: Development and Application to the Total Synthesis of (+)‐Alstratine A

Qian Wang, Jieping Zhu, Rémi Julien Sylvain Andres, Fenggang Sun

We report herein an asymmetric Pictet– Spengler reaction of α-ketoesters. In the presence of a catalytic amount of simple alanine-derived squaramide and p-nitrobenzoic acid, reaction of tryptamines with methyl 2-oxoalkanoates afforded the corresponding 1- ...

Wiley-VCH Verlag GmbH2023

A synthetic phase-contrast imaging diagnostic with spatial filtering for gyrokinetic simulations

Stefano Coda, Stephan Brunner, Justin Richard Ball, Gabriele Merlo, Aylwin Iantchenko

A Phase-contrast imaging (PCI) diagnostic provides measurements of line-integrated electron density fluctuations. Localisation along the laser beam path can be achieved with a spatial filter that selects the wave-vector directions of the fluctuations contr ...

2023

Gas/Surface reactions probed by reflection absorption infrared spectroscopy

Harmina Vejayan

In my thesis, I present an investigation of the dissociation reactions of gas phase molecules on single crystal metal surfaces studied by a molecular beam in combination with Reflection Absorption Infrared Spectroscopy (RAIRS). Two gas/surface systems were ...

EPFL2023

The role of Zn in C-S-H atomic structure, nucleation and growth

Anna Morales Melgares

The most promising solution towards cementitious materials with a lower carbon footprint is the partial substitution of the clinker by supplementary cementitious materials (SCMs) such as fly ash, blast furnace slag, limestone and calcined clays. The produc ...

EPFL2023

Mechanistic modelling of solar disinfection (SODIS) kinetics of Escherichia coli, enhanced with H2O2 - part 1: The dark side of peroxide

César Pulgarin, Stefanos Giannakis, Ling Feng

The present bi-partite work describes the development and validation of a mechanistic kinetic model of SODIS E. coli inactivation, enhanced with H2O2. In this first part, the mechanism of the baseline dark phenomena is modelled. A mechanistic model involvi ...

ELSEVIER SCIENCE SA2022

Mechanistic modelling of solar disinfection (SODIS) kinetics of Escherichia coli, enhanced with H2O2 - Part 2: Shine on you, crazy peroxide

César Pulgarin, Stefanos Giannakis, Ling Feng

In this second part of the development of a mechanistic kinetic model of the solar inactivation of E. coli enhanced with hydrogen peroxide, we evaluate the mechanisms based on photonic inactivation and integrate them into the kinetic model of the dark proc ...

ELSEVIER SCIENCE SA2022

Catalytic Enantioselective Pictet–Spengler Reaction of α‐Ketoamides Catalyzed by a Single H‐Bond Donor Organocatalyst

Jieping Zhu, Qiang Wang, Rémi Julien Sylvain Andres

The asymmetric Pictet–Spengler reaction (PSR) with aldehydes is well known. However, PSR involving ketones as electrophilic partners is far-less developed. We report herein the first examples of catalytic enantioselective PSR of tryptamines with α-ketoamid ...

Wiley-VCH Verlag GmbH2022

Molecular dynamics simulations of the evaporation of hydrated ions from aqueous solution

Philip Robin Loche

Although important for atmospheric processes and gas-phase catalysis, very little is known about the hydration state of ions in the vapor phase. Here we study the evaporation energetics and kinetics of a chloride ion from liquid water by molecular dynamics ...

NATURE PORTFOLIO2022

Assessing the value of kinetic results from biochemical methane potential tests: Reproducibility from a large inter-laboratory study

Christof Holliger

Kinetic information extracted from biochemical methane potential (BMP) tests is often reported but its value is unclear. Inter-laboratory reproducibility provides a useful indication of its value. Here we extracted estimates of the first-order rate constan ...

2022

Precipitation fate and transport in a Mediterranean catchment through models calibrated on plant and stream water isotope data

Paolo Benettin

To predict hydrologic responses to inputs and perturbations, it is important to understand how precipitation is stored in catchments, released back to the atmosphere via evapotranspiration (ET), or transported to aquifers and streams. We investigated this ...

COPERNICUS GESELLSCHAFT MBH2022

In depth analysis of heterogeneous catalysts for the chemoenzymatic dynamic kinetic resolution of beta-amino esters

Kumar Varoon Agrawal, Cédric Karel J Van Goethem

The chemoenzymatic dynamic kinetic resolution of beta-amino esters is established after detailed evaluation of metal-based heterogeneous catalysts for racemization and enzyme catalysts for kinetic resolution. Several heterogeneous palladium catalysts prove ...

ROYAL SOC CHEMISTRY2022

Design of the 590 MeV proton beamline for the proposed TATTOOS isotope production target at PSI

Mike Seidel, Hong Zhang

IMPACT (Isotope and Muon Production with Advanced Cyclotron and Target Technologies) is a proposed initiative envisaged for the high-intensity proton accelerator facility (HIPA) at the Paul Scherrer Institute (PSI). As part of IMPACT, a radioisotope target ...

IOP Publishing2022

Characterization of Chemisorbed Species and Active Adsorption Sites in Mg-Al Mixed Metal Oxides for High-Temperature CO2 Capture

Berend Smit, Kevin Maik Jablonka, Susana Garcia Lopez, Christopher Patrick Ireland

Mg-Al mixed metal oxides (MMOs), derived from the decomposition of layered double hydroxides (LDHs), have been purposed as adsorbents for CO2 capture of industrial plant emissions. To aid in the design and optimization of these materials for CO2 capture at ...

AMER CHEMICAL SOC2022