Data Science

In this paper, we present an e-nose for the detection of volatile compounds based on an array of six surface acoustic wave (SAW) resonators coated with five different polymers (i.e. polyepichlorohydrin, polyisobutylene, polyethylenimine, (hydroxypropyl)methyl cellulose, and poly(styrene-co-maleic acid) partial isobutyl/methyl mixed ester, plus an uncoated SAW device used as reference.

Heterogeneous and combined hetero/homogeneous chemical processes have attracted increased attention in many energy conversion systems, which include large scale power generation, microreactors for portable power generation, household burners, fuel processing technologies and automotive exhaust gas aftertreatment. Progress in such systems crucially depends on the development of catalysts with enhanced activity and thermal stability and on the comprehensive understanding of the fundamental processes occurring near gas solid reacting interfaces.

The compounds A₂Cu₃O(SO₄)₃(A=Na,K) are characterized by copper hexamers which are weakly coupled along the b axis to realize one-dimensional antiferromagnetic chains below T_N≈3K, whereas the interchain interactions along the a and c axes are negligible. We investigated the energy-level splittings of the copper hexamers by inelastic neutron scattering below and above T_N.

We have developed a new cruciform geometry with reduced thickness at the center, which allows reaching high plastic strain under equibiaxial loading. The novel thinning method results in excellent surface quality, suitable for electron backscatter diffraction (EBSD) and high-resolution digital image correlation (HRDIC) investigations. We performed an in-situ HRDIC study on a 304 austenitic stainless steel using the new cruciform geometry to follow the slip activity under uniaxial and equibiaxial loadings.

Catalytic materials are ubiquitously used in industrial processes to perform chemical reactions efficiently and in a sustainable manner. Nanoporous gold (npAu) is a monolithic sponge-like catalyst exhibiting a hierarchical structure with pores and connecting ligaments of typically 10 to 50 nm.

The mechanical behavior of cold-rolled Mg AZ31B is studied during in-plane multiaxial loading and tension-tension strain path changes using in situ neutron diffraction and electron backscatter diffracion.

Multiple-q spin order, i.e., a spin texture characterized by a multiple number of coexisting magnetic modulation vec- tors q, has recently attracted attention as a source of nontrivial magnetic topology and associated emergent phenome- na. One typical example is the triple-q skyrmion lattice state stabilized by Dzyaloshinskii-Moriya interactions in noncentrosymmetric magnets, while the emergence of various multiple-q states of different origins is expected according to the latest theories.

Nanocrystalline cellulose (NCC) is a promising biological nanoparticle for the stabilization of fluid interfaces, which is however poorly understood due to the inability to form controlled NCC interfacial layers. Herein we present parameters that allow the adsorption of unmodified NCC at the air-water (A/W) interface. Initial NCC adsorption is limited by diffusion, followed by monolayer saturation and decrease in surface tension at the time scale of hours.

MSR research at LSM has 3 main justifications:

1. education purpose (2 PhD & 8 MSc internal students, 3 PhD & 4 other guests)

2. technology monitoring (it is the most revolutionary GIV system)

3. novel research topics (liquid phase of the fuel introduces many challenges)

Two major research objectives in NES:

1. safety: evaluate system behavior in nominal and transient conditions (tight multi‐physics coupling / H2020 SAMOFAR project)

2. sustainability: evaluate if the concept can use legacy nuclear waste as initial fuel, insure a high resource utilization (high burning)

Fast and accurate data collection for macromolecular crystallography using the JUNGFRAU detector.

Coupling between dynamical heterogeneity of ionic liquids and their structural periodicity on different length-scales can be directly probed by quasielastic neutron scattering with polarization analysis. The technique provides the tools to investigate single-particle and cooperative ion motions separately and, thus, dynamics of ion associations affecting the net charge transport can be experimentally explored.

Methylperoxy radicals are crucial oxidation intermediates and could be synthesized photolytically in an exothermic reaction. Despite their vanishingly small concentration, their temperature could be measured after a few ten thousand collisions inside the reactor, which opens up the possibility of time-resolved operando temperature measurements. Also the reaction energy to yield methyl cations and oxygen could be determined with sub-kJ mol^–1 precision, which firmly anchors the methylperoxy energetics to that of well-known stable species and opens up the possibility of highly accurate radical thermochemistry measurements.

Studying organic molecular magnets is a challenge, because the high-spin diradical character of these compounds dramatically increases the reactivity and reduces the lifetime. Researchers from PSI, ETH Zurich, Wollongong and Melbourne, Australia succeeded in taming the meta-xylylene diradical and were able to study its electronic and thermochemical properties.

Scattering experiments establish the partly disordered material CsNiCrF₆ as the first verified example of a charge ice — and show that it supports Coulomb phases with correlations in three different degrees of freedom.

We use resonant and nonresonant x-ray diffraction measurements in combination with first-principles electronic structure calculations and Monte Carlo simulations to study the relationship between crystal structure and multiferroic orders in the orthorhombic perovskite manganites, o−RMnO₃ (R is a rare-earth cation or Y).

In insulating materials with ordered magnetic spiral phases, ferroelectricity can emerge owing to the breaking of in- version symmetry. This property is of both fundamental and practical interest, particularly with a view to exploiting it in low-power electronic devices. Advances toward technological applications have been hindered, however, by the rel- atively low ordering temperatures T_spiral of most magnetic spiral phases, which rarely exceed 100 K.

The mobility of magnetic domains forms the link between the basic physical properties of a magnetic material and its global characteristics such as permeability and saturation field. Most commonly, surface domain structure are studied using magneto-optical Kerr microscopy. The limited information depth of approx. 20 nanometers, however, allows only for an indirect interpretation of the internal volume domain structures.

We report significant photoelectrochemical activity of Y-doped BiFeO₃ (Y-BFO) epitaxial thin films deposited on Nb:SrTiO₃ substrates. The Y-BFO photoanodes exhibit a strong dependence of the photocurrent values on the thickness of the films, and implicitly on the induced epitaxial strain.

Coordination complexes of magnesium borohydride show promising properties as solid electrolytes for magnesium ion batteries and warrant a thorough microscopic description of factors governing their mobility properties. Here, the dynamics of Mg(BH₄)₂-diglyme_0.5 on the atomic level are investigated by means of quasielastic neutron scattering supported by density functional theory calculations and IR and NMR spectroscopy.

In a trio of recent papers, a research group from the University of Zürich has made a number of new discoveries about the nature of cuprates' electronic structure and orbital composition. The results have important implications for superconductivity and pseudogaps in cuprates, and even the existence of type-II Dirac fermions in oxides.