Institution
Paul Scherrer Institute
Facility•Villigen, Switzerland•
About: Paul Scherrer Institute is a facility organization based out in Villigen, Switzerland. It is known for research contribution in the topics: Neutron & Large Hadron Collider. The organization has 9248 authors who have published 23984 publications receiving 890129 citations. The organization is also known as: PSI.
Topics: Neutron, Large Hadron Collider, Aerosol, Magnetization, Muon
Papers published on a yearly basis
Papers
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TL;DR: This paper shows, using a combination of diffraction techniques, that the hexagonal manganites RMnO3 undergo an isostructural transition with exceptionally large atomic displacements: two orders of magnitude larger than those seen in any other magnetic material, resulting in an unusually strong magneto-elastic coupling.
Abstract: The motion of atoms in a solid always responds to cooling or heating in a way that is consistent with the symmetry of the given space group of the solid to which they belong1,2. When the atoms move, the electronic structure of the solid changes, leading to different physical properties. Therefore, the determination of where atoms are and what atoms do is a cornerstone of modern solid-state physics. However, experimental observations of atomic displacements measured as a function of temperature are very rare, because those displacements are, in almost all cases, exceedingly small3,4,5. Here we show, using a combination of diffraction techniques, that the hexagonal manganites RMnO3 (where R is a rare-earth element) undergo an isostructural transition with exceptionally large atomic displacements: two orders of magnitude larger than those seen in any other magnetic material, resulting in an unusually strong magneto-elastic coupling. We follow the exact atomic displacements of all the atoms in the unit cell as a function of temperature and find consistency with theoretical predictions based on group theories. We argue that this gigantic magneto-elastic coupling in RMnO3 holds the key to the recently observed magneto-electric phenomenon in this intriguing class of materials6.
302 citations
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TL;DR: In this paper, the performance of the carbon negative electrode, which is composed of TIMREX SFG synthetic graphite material of varying particle size distribution, was investigated and a transport limitation model was proposed to explain the restrictions of the high current performance of graphite electrodes.
Abstract: The rate capability of various lithium-ion half-cells was investigated. Our study focuses on the performance of the carbon negative electrode, which is composed of TIMREX SFG synthetic graphite material of varying particle size distribution. All cells showed high discharge and comparatively low charge rate capability. Up to the 20 C rate, discharge capacity retention of more than 96% was found for SFG6. The rate capability of the half-cells is a function of both the particle size distribution of the graphite material and the preparation method of the electrode. A transport limitation model is proposed to explain the restrictions of the high current performance of graphite electrodes. The key parameters found to influence the performance of a graphite negative electrode were the loading, the thickness, and the porosity of the electrode.
302 citations
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University of Helsinki1, Paul Scherrer Institute2, Goethe University Frankfurt3, University of Beira Interior4, University of Innsbruck5, California Institute of Technology6, University of Leeds7, Finnish Meteorological Institute8, University of Eastern Finland9, CERN10, University of Vienna11, Leibniz Association12, Carnegie Mellon University13
TL;DR: High-resolution mass spectra of ion clusters observed during new particle formation experiments performed at the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research confirm that oxidized organics are involved in both the formation and growth of particles under ambient conditions.
Abstract: Atmospheric aerosols formed by nucleation of vapors affect radiative forcing and therefore climate. However, the underlying mechanisms of nucleation remain unclear, particularly the involvement of organic compounds. Here, we present high-resolution mass spectra of ion clusters observed during new particle formation experiments performed at the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research. The experiments involved sulfuric acid vapor and different stabilizing species, including ammonia and dimethylamine, as well as oxidation products of pinanediol, a surrogate for organic vapors formed from monoterpenes. A striking resemblance is revealed between the mass spectra from the chamber experiments with oxidized organics and ambient data obtained during new particle formation events at the Hyytiala boreal forest research station. We observe that large oxidized organic compounds, arising from the oxidation of monoterpenes, cluster directly with single sulfuric acid molecules and then form growing clusters of one to three sulfuric acid molecules plus one to four oxidized organics. Most of these organic compounds retain 10 carbon atoms, and some of them are remarkably highly oxidized (oxygen-to-carbon ratios up to 1.2). The average degree of oxygenation of the organic compounds decreases while the clusters are growing. Our measurements therefore connect oxidized organics directly, and in detail, with the very first steps of new particle formation and their growth between 1 and 2 nm in a controlled environment. Thus, they confirm that oxidized organics are involved in both the formation and growth of particles under ambient conditions.
301 citations
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TL;DR: In this article, a defect model based on low-temperature oxygen non-stoichiometry data is formulated and extrapolated to higher temperatures more relevant to thermochemical redox cycles.
Abstract: A thermodynamic and experimental investigation of a new class of solar thermochemical redox intermediates, namely, lanthanum–strontium–manganese perovskites, is presented. A defect model based on low-temperature oxygen non-stoichiometry data is formulated and extrapolated to higher temperatures more relevant to thermochemical redox cycles. Strontium contents of x = 0.3 (LSM30) and x = 0.4 (LSM40) in La1–xSrxMnO3−δ result in favorable reduction extents compared to ceria in the temperature range of 1523–1923 K. Oxidation with CO2 and H2O is not as thermodynamically favorable and largely dependent upon the oxidant concentration. The model is experimentally validated by O2 non-stoichiometry measurements at high temperatures (>1623 K) and CO2 reduction cycles with commercially available LSM35. Theoretical solar–fuel energy conversion efficiencies for LSM40 and ceria redox cycles are 16 and 22% at 1800 K and 13 and 7% at 1600 K, respectively.
301 citations
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TL;DR: Temperature was a suitable surrogate for deriving estimates of annual Rs and temperature-independent seasonal fluctuations of Rs of an intensively managed pasture were closely related to changes in leaf area index (LAI), indicating that assimilate supply overrides potential acclimation to prevailing temperatures.
Abstract: Soil respiration constitutes the second largest flux of carbon (C) between terrestrial ecosystems and the atmosphere. This study provides a synthesis of soil respiration (R
s) in 20 European grasslands across a climatic transect, including ten meadows, eight pastures and two unmanaged grasslands. Maximum rates of R
s (
$$ R_{{{\text{s}}_{{{\text{max}}}} }} $$
), R
s at a reference soil temperature (10°C; $$ R_{{{\text{s}}_{{{\text{10}}}} }} $$
) and annual R
s (estimated for 13 sites) ranged from 1.9 to 15.9 μmol CO2 m−2 s−1, 0.3 to 5.5 μmol CO2 m−2 s−1 and 58 to 1988 g C m−2 y−1, respectively. Values obtained for Central European mountain meadows are amongst the highest so far reported for any type of ecosystem. Across all sites $$ R_{{{\text{s}}_{{{\text{max}}}} }} $$
was closely related to $$ R_{{{\text{s}}_{{{\text{10}}}} }} $$
. Assimilate supply affected R
s at timescales from daily (but not necessarily diurnal) to annual. Reductions of assimilate supply by removal of aboveground biomass through grazing and cutting resulted in a rapid and a significant decrease of R
s. Temperature-independent seasonal fluctuations of R
s of an intensively managed pasture were closely related to changes in leaf area index (LAI). Across sites $$ R_{{{\text{s}}_{{{\text{10}}}} }} $$
increased with mean annual soil temperature (MAT), LAI and gross primary productivity (GPP), indicating that assimilate supply overrides potential acclimation to prevailing temperatures. Also annual R
s was closely related to LAI and GPP. Because the latter two parameters were coupled to MAT, temperature was a suitable surrogate for deriving estimates of annual R
s across the grasslands studied. These findings contribute to our understanding of regional patterns of soil C fluxes and highlight the importance of assimilate supply for soil CO2 emissions at various timescales.
301 citations
Authors
Showing all 9348 results
Name | H-index | Papers | Citations |
---|---|---|---|
Andrea Bocci | 172 | 2402 | 176461 |
Tobin J. Marks | 159 | 1621 | 111604 |
Wolfgang Wagner | 156 | 2342 | 123391 |
David D'Enterria | 150 | 1592 | 116210 |
Andreas Pfeiffer | 149 | 1756 | 131080 |
Christoph Grab | 144 | 1359 | 144174 |
Maurizio Pierini | 143 | 1782 | 104406 |
Alexander Belyaev | 142 | 1895 | 100796 |
Ajit Kumar Mohanty | 141 | 1124 | 93062 |
Felicitas Pauss | 141 | 1623 | 104493 |
Chiara Mariotti | 141 | 1426 | 98157 |
Luc Pape | 141 | 1441 | 130253 |
Rainer Wallny | 141 | 1661 | 105387 |
Roland Horisberger | 139 | 1471 | 100458 |
Emmanuelle Perez | 138 | 1550 | 99016 |