Superlattices in van der Waals materials: a low-energy electron microscopy study

In this PhD thesis, the recombination of different atomic lattices in stacked 2D materials such as twisted bilayer graphene is studied. Using the different possibilities of Low-Energy Electron Microscopy (LEEM), the domain forming between the two atomic layers with small differences is studied. Superlattices in three such 2D material systems are studied. In twisted bilayer graphene, the small difference is caused by a twist of approximately one degree between the layers. In graphene on SiC, the difference is caused by the lattice mismatch between a buffer layer bound to the substrate and the next graphene layer. For both, we show that domains of different shapes and sizes occur and relate them to strain and lattice mismatch. The third system studied is tantalum disulfide. In this layered material, two different superlattices occur: a superlattice between atomic layers with different atomic arrangements in the layers, so-called polytypes, and the superlattices between the atomic lattice and the Charge Density Waves (CDW). CDWs cause a large temperature dependent resistivity change. The influence of a mixture of different polytypes on the precise CDW states is studied using LEEM spectroscopy and local Low-Energy Electron Diffraction.This work was financed by the Dutch Research Council (NWO) as part of the Frontiers of Nanoscience programmeQuantum Matter and Optic

Grootschalige landbouw in een kleinschalig landschap : oplossingsrichtingen voor toekomstgerichte grootschalige melkveehouderij uitgewerkt voor het kleinschalige, open veenweidelandschap van Laag Holland

Schaalvergroting wordt door de meeste veehouderijbedrijven gezien als een belangrijke mogelijkheid om de kostprijs te verlagen. Maar vooral in kleinschalige gebieden lopen grotere bedrijven tegen de grenzen van hun omgeving aan. Vanuit de maatschappij klinkt immers de roep om een mooier landschap en hogere natuurwaarden. In de brochure 'Grootschalige landbouw in een kleinschalig landschap' zijn oplossingsrichtingen voor toekomstgerichte grootschalige melkveehouderij uitgewerkt voor het kleinschalige, open veenweidelandschap van Laag Holland

Melkveebedrijven met beheersbepalingen in zandgebieden : gebiedsstudie Hackfort

Onderzoek naar de mogelijkheden en effecten van natuur- en landschapsbeheer door melkveebedrijven in zandgebieden. Voor het studiegebied Hackfort zijn 4 beheersmodellen opgesteld. De gevolgen van de beheersmodellen zijn m.b.v. lineaire programmering berekend voor 3 hoofdberoepsbedrijfstypen met melkvee: extensief met grupstal, matig intensief met ligboxenstal en intensief met ligboxenstal. Per bedrijfstype zijn 6 varianten gemaakt met een verschillend percentage bedrijfsoppervlakte met beperkingen, en wel of geen toevoeging van reservaatsgron

Delays in Biological Regulatory Networks

International audienceIn this article, we propose a refinement of the modeling of genetic regulatory networks based on the approach of René Thomas. The notion of delays of activation/inhibition are added in order to specify which variable is faster affected by a change of its regulators. The formalism of linear hybrid automata is well suited to allow such refinement. We then use HyTech for two purposes: (1) to find automatically all paths from a specified initial state to another one and (2) to synthesize co nstraints on the delay parameters in order to follow any specific path

Why do firms go public?

Ambitious chief executives considering the possibility of floating their company on a major stock exchange should be careful what they wish for. They need to be sure that they are making the decision for the right reasons, at the right time, and that the initial public offering (IPO) is made in the right location

A “laboratory of knowledge-making” for personal inquiry learning

We describe nQuire, a constraint-based learning toolkit to support a continuity of inquiry based learning between classroom and non-formal settings. The paper proposes design requirements for personal inquiry learning environments that support learning of personally meaningful science topics with development of metacognitive understanding and self-regulation of the scientific process through situated practice. It introduces a generic implementable model of the inquiry process, and describes an instantiation in the nQuire learning environment. An example of the use of the toolkit for a Healthy Eating inquiry with 28 Year 9 students concludes with results of the trial, design issues and recommendations