MESA Institute for Nanotechnology

Enschede, Netherlands

MESA Institute for Nanotechnology

Enschede, Netherlands
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Van Der Meer D.,MESA Institute for Nanotechnology
Annual Review of Fluid Mechanics | Year: 2017

The impact of an object on a granular solid is an ubiquitous phenomenon in nature, the scale of which ranges from the impact of a raindrop onto sand all the way to that of a large asteroid on a planet. Despite the obvious relevance of these impact events, the study of the underlying physics mechanisms that guide them is relatively young, with most work concentrated in the past decade. Upon impact, an object starts to interact with a granular bed and experiences a drag force from the sand. This ultimately leads to phenomena such as crater formation and the creation of a transient cavity that upon collapse may cause a jet to appear from above the surface of the sand. This review provides an overview of research that targets these phenomena, from the perspective of the analogous but markedly different impact of an object on a liquid. It successively addresses the drag an object experiences inside a granular bed, the expansion and collapse of the cavity created by the object leading to the formation of a jet, and the remarkable role played by the air that resides within the pores between the grains. © Copyright 2017 by Annual Reviews. All rights reserved.

Tormo P.,Aalto University | Barnes W.L.,University of Exeter | Barnes W.L.,MESA Institute for Nanotechnology
Reports on Progress in Physics | Year: 2015

In this review we look at the concepts and state-of-the-art concerning the strong coupling of surface plasmon-polariton modes to states associated with quantum emitters such as excitons in J-aggregates, dye molecules and quantum dots. We explore the phenomenon of strong coupling with reference to a number of examples involving electromagnetic fields and matter. We then provide a concise description of the relevant background physics of surface plasmon polaritons. An extensive overview of the historical background and a detailed discussion of more recent relevant experimental advances concerning strong coupling between surface plasmon polaritons and quantum emitters is then presented. Three conceptual frameworks are then discussed and compared in depth: classical, semi-classical and fully quantum mechanical; these theoretical frameworks will have relevance to strong coupling beyond that involving surface plasmon polaritons. We conclude our review with a perspective on the future of this rapidly emerging field, one we are sure will grow to encompass more intriguing physics and will develop in scope to be of relevance to other areas of science. © 2015 IOP Publishing Ltd.

Stockl M.T.,MESA Institute for Nanotechnology
Molecular neurobiology | Year: 2013

In many human diseases, oligomeric species of amyloid proteins may play a pivotal role in cytotoxicity. Many lines of evidence indicate that permeabilization of cellular membranes by amyloid oligomers may be the key factor in disrupting cellular homeostasis. However, the exact mechanisms by which the membrane integrity is impaired remain elusive. One prevailing hypothesis, the so-called amyloid pore hypothesis, assumes that annular oligomeric species embed into lipid bilayers forming transbilayer protein channels. Alternatively, an increased membrane permeability could be caused by thinning of the hydrophobic core of the lipid bilayer due to the incorporation of the oligomers between the tightly packed lipids, which would facilitate the transport of small molecules across the membrane. In this review, we briefly recapitulate our findings on the structure of α-synuclein oligomers and the factors influencing their interaction with lipid bilayers. Our results, combined with work from other groups, suggest that α-synuclein oligomers do not necessarily form pore-like structures. The emerging consensus is that local structural rearrangements of the protein lead to insertion of specific regions into the hydrophobic core of the lipid bilayer, thereby disrupting the lipid packing.

Krabbenborg S.O.,MESA Institute for Nanotechnology | Huskens J.,MESA Institute for Nanotechnology
Angewandte Chemie - International Edition | Year: 2014

This review surveys recent developments in the field of electrochemically generated gradients. The gradual variation of properties, which is a key characteristic of gradients, is of eminent importance in technology, for example, directional wetting, as well as biology, for example, chemotaxis. Electrochemical techniques offer many benefits, such as the generation of dynamic solution and surface gradients, integration with electronics, and compatibility with automation. An overview is given of newly developed methods, from purely electrochemical techniques to the combination of electrochemistry with other methods. Electrochemically fabricated gradients are employed extensively for biological and technological applications, such as high-throughput screening, high-throughput deposition, and device development, all of which are covered herein. Especially promising are developments towards the study and control of dynamic phenomena, such as the directional motion of molecules, droplets, and cells. Biased toward gradient formation: The use of electrochemistry to generate gradients (see picture) has many benefits, such as the ability to generate dynamic solution and surface gradients, the integration of electronics, and compatibility with automation. The resulting gradients have been employed extensively for biological and technological applications, such as high-throughput screening, high-throughput deposition, and device development. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zandvliet H.J.W.,MESA Institute for Nanotechnology
Nano Today | Year: 2014

In the past decade a new exciting class of materials has been developed, which is not three-dimensional, but only two-dimensional in nature. Graphene is by far the most famous example of this new class of materials. Graphene exhibits a wealth of exotic and intriguing properties, which has resulted in a myriad of scientific breakthroughs. However, graphene also suffers from a severe drawback: it is gapless, implying that a graphene based field-effect transistor is not within reach. Silicene, the silicon analog of graphene, is in many aspects very similar to graphene, but in contrast to the planar graphene lattice, the silicene lattice is slightly buckled and composed of two vertically displaced sub-lattices. By breaking the sub-lattice symmetry a band gap can be opened, which would in principle allow the realization of a silicene field-effect transistor. This piece introduces the various band engineering options for silicene as well as additional hurdles that will need to be overcome before the door can be opened to a silicene transistor. © 2014 Elsevier Ltd. All rights reserved.

Bradley J.D.B.,MESA Institute for Nanotechnology | Pollnau M.,MESA Institute for Nanotechnology
Laser and Photonics Reviews | Year: 2011

Erbium-doped fiber devices have been extraordinarily successful due to their broad optical gain around 1.5-1.6 μm. Er-doped fiber amplifiers enable efficient, stable amplification of high-speed, wavelength-division-multiplexed signals, thus continue to dominate as part of the backbone of longhaul telecommunications networks. At the same time, Er-doped fiber lasers see many applications in telecommunications as well as in biomedical and sensing environments. Over the last 20 years significant efforts have been made to bring these advantages to the chip level. Device integration decreases the overall size and cost and potentially allows for the combination of many functions on a single tiny chip. Besides technological issues connected to the shorter device lengths and correspondingly higher Er concentrations required for high gain, the choice of appropriate host material as well as many design issues come into play in such devices. In this contribution the important developments in the field of Er-doped integrated waveguide amplifiers and lasers are reviewed and current and future potential applications are explored. The vision of integrating such Er-doped gain devices with other, passive materials platforms, such as silicon photonics, is discussed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Weijs J.H.,MESA Institute for Nanotechnology | Lohse D.,MESA Institute for Nanotechnology
Physical Review Letters | Year: 2013

We present a theoretical model for the experimentally found but counterintuitive exceptionally long lifetime of surface nanobubbles. We can explain why, under normal experimental conditions, surface nanobubbles are stable for many hours or even up to days rather than the expected microseconds. The limited gas diffusion through the water in the far field, the cooperative effect of nanobubble clusters, and the pinned contact line of the nanobubbles lead to the slow dissolution rate. © 2013 American Physical Society.

Controlled in-plane rotation of the magnetic easy axis in manganite heterostructures by tailoring the interface oxygen network could allow the development of correlated oxide-based magnetic tunnelling junctions with non-collinear magnetization, with possible practical applications as miniaturized high-switching-speed magnetic random access memory (MRAM) devices. Here, we demonstrate how to manipulate magnetic and electronic anisotropic properties in manganite heterostructures by engineering the oxygen network on the unit-cell level. The strong oxygen octahedral coupling is found to transfer the octahedral rotation, present in the NdGaO3 (NGO) substrate, to the La2/3Sr1/3MnO3 (LSMO) film in the interface region. This causes an unexpected realignment of the magnetic easy axis along the short axis of the LSMO unit cell as well as the presence of a giant anisotropic transport in these ultrathin LSMO films. As a result we possess control of the lateral magnetic and electronic anisotropies by atomic-scale design of the oxygen octahedral rotation. © 2016 Nature Publishing Group

Eijkel J.C.T.,MESA Institute for Nanotechnology | Van Den Berg A.,MESA Institute for Nanotechnology
Chemical Society Reviews | Year: 2010

The properties and behavior of solvents and solutes inside a nanofluidic structure are not the same as in the bulk solution, but instead are strongly determined by the interactions of solvent and solute molecules with the walls of the structure. These interactions give rise to nanometre-scale boundary layers where the properties can strongly differ from the bulk. The chemical potential provides a convenient tool to describe these boundary layers, and as such is the focus of this tutorial review. The chemical potential of a solution component describes its energy level, which in this boundary layer is strongly influenced by the various interfacial forces between molecules in the wall and in the solution. These forces vary with distance and have a certain limited spatial range, which is reflected in the composition and thickness of the boundary layer in which both solute and solvent concentrations differ from their bulk values. We will consider a variety of solutes such as ions, uncharged molecules and gases, and surfaces that are both hydrophilic and hydrophobic. The boundary layer is oriented normal to the surface, but external forces can also be applied in parallel to the surface. Many interesting different nanofluidic transport phenomena then result, which will also be briefly mentioned in this tutorial review. By this common approach of using the chemical potential for nanofluidic systems of different composition, we aim to bring out the conceptual similarity between the different types of boundary layers and the different transport processes they can give rise to. Finally, as much as possible we will always mention (potential) real-life applications. © 2010 The Royal Society of Chemistry.

Versluis M.,MESA Institute for Nanotechnology
Experiments in Fluids | Year: 2013

High-speed imaging is in popular demand for a broad range of experiments in fluids. It allows for a detailed visualization of the event under study by acquiring a series of image frames captured at high temporal and spatial resolution. This review covers high-speed imaging basics, by defining criteria for high-speed imaging experiments in fluids and to give rule of thumbs for a series of cases. It also considers stroboscopic imaging, triggering and illumination, and scaling issues. It provides guidelines for testing and calibration. Ultra-high-speed imaging at frame rates exceeding 1 million frames per second is reviewed, and the combination of conventional experiments in fluid techniques with high-speed imaging techniques is discussed. The review is concluded with a high-speed imaging chart, which summarizes criteria for temporal scale and spatial scale and which facilitates the selection of a high-speed imaging system for the application. © 2013 Springer-Verlag Berlin Heidelberg.

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