98 research outputs found
Unraveling the Complexity of Splitting Sequential Data: Tackling Challenges in Video and Time Series Analysis
Splitting of sequential data, such as videos and time series, is an essential
step in various data analysis tasks, including object tracking and anomaly
detection. However, splitting sequential data presents a variety of challenges
that can impact the accuracy and reliability of subsequent analyses. This
concept article examines the challenges associated with splitting sequential
data, including data acquisition, data representation, split ratio selection,
setting up quality criteria, and choosing suitable selection strategies. We
explore these challenges through two real-world examples: motor test benches
and particle tracking in liquids
Colloidal topological insulators
Topological insulators insulate in the bulk but exhibit robust conducting
edge states protected by the topology of the bulk material. Here, we design a
colloidal topological insulator and demonstrate experimentally the occurrence
of edge states in a classical particle system. Magnetic colloidal particles
travel along the edge of two distinct magnetic lattices. We drive the colloids
with a uniform external magnetic field that performs a topologically
non-trivial modulation loop. The loop induces closed orbits in the bulk of the
magnetic lattices. At the edge, where both lattices merge, the colloids perform
skipping orbits trajectories and hence edge-transport. We also observe
paramagnetic and diamagnetic colloids moving in opposite directions along the
edge between two inverted patterns; the analogue of a quantum spin Hall effect
in topological insulators. We present a new, robust, and versatile way of
transporting colloidal particles, enabling new pathways towards lab on a chip
applications
Magnetic patterning of Co/Ni layered systems by plasma oxidation
We studied the structural, chemical, and magnetic properties of Ti/Au/Co/Ni layered systems subjected to plasma oxidation. The process results in the formation of NiO at the expense of metallic Ni, as clearly evidenced by X-ray photoelectron spectroscopy, while not affecting the surface roughness and grain size of the Co/Ni bilayers. Since the decrease of the thickness of the Ni layer and the formation of NiO increase the perpendicular magnetic anisotropy, oxidation may be locally applied for magnetic patterning. Using this approach, we created 2D heterostructures characterized by different combinations of magnetic properties in areas modified by plasma oxidation and in the regions protected from oxidation. As plasma oxidation is an easy to use, low cost, and commonly utilized technique in industrial applications, it may constitute an improvement over other magnetic patterning methods
Simultaneous polydirectional transport of colloidal bipeds
Detailed control over the motion of colloidal particles is relevant in many
applications in colloidal science such as lab-on-a-chip devices. Here, we use
an external magnetic field to assemble paramagnetic colloidal spheres into
colloidal rods of several lengths. The rods reside above a square magnetic
pattern and are transported via modulation of the direction of the external
magnetic field. The rods behave like bipeds walking above the pattern.
Depending on their length, the bipeds perform topologically distinct classes of
protected walks above the pattern. We demonstrate that it is possible to design
parallel polydirectional modulation loops of the external field that command up
to six classes of bipeds to walk on distinct predesigned paths. We use such
parallel polydirectional loops to induce the collision of reactant bipeds,
their polymerization addition reaction to larger bipeds, the separation of
product bipeds from the educts, the sorting of different product bipeds, and
also the parallel writing of a word consisting of several different letters
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Interatomic and Intermolecular Coulombic Decay
Interatomic or intermolecular Coulombic decay (ICD) is a nonlocal electronic decay mechanism occurring in weakly bound matter. In an ICD process, energy released by electronic relaxation of an excited atom or molecule leads to ionization of a neighboring one via Coulombic electron interactions. ICD has been predicted theoretically in the mid nineties of the last century, and its existence has been confirmed experimentally approximately ten years later. Since then, a number of fundamental and applied aspects have been studied in this quickly growing field of research. This review provides an introduction to ICD and draws the connection to related energy transfer and ionization processes. The theoretical approaches for the description of ICD as well as the experimental techniques developed and employed for its investigation are described. The existing body of literature on experimental and theoretical studies of ICD processes in different atomic and molecular systems is reviewed. © 2020 American Chemical Societ
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