Search results for "rakenteet"
showing 10 items of 174 documents
Vallan verkostoissa : Per Brahe ja hänen klienttinsä 1600-luvun Ruotsin valtakunnassa
2011
Suomi ja kriittisen militarismitutkimuksen tarve
2021
Esittelemme kriittistä militarismitutkimusta (engl. Critical Mfilitary Studies) ja tutkimuksellisia näkökulmia suomalaiseen militarismiin ja militarisaatioon. Pohdimme, millaisia ilmentymiä militarismi ja militarisaatio saavat Suomessa, ja hahmottelemme mahdollisia tulevan tutkimuksen suuntia. Pyrimme herättämään keskustelua suomalaisen yhteiskunnan militarisaatiosta, sotilaallisen vallan koskemattomuudesta sekä ekseptionalistisesta asemasta suomalaisessa yhteiskunnassa. Tuomme esiin tarvetta kriittiselle militarismitutkimukselle avoimemman ja monipuolisemman sotilaallista valtaa koskevan keskustelun ja tutkimuksen edistämiseksi. Esittelemme lyhyesti kansainvälisen tutkimuksen kenttää, ja t…
Mind your Manners : Agamben and Phish
2021
In the final volume of his Homo Sacer series Giorgio Agamben develops the concept of destituent power, a power that unworks itself in every constitution and renders itself inoperative in its every operation. This concept helps elucidate Agamben’s more enigmatic notion of form-of-life. Whereas the power of sovereign biopolitics is constitutive, i.e. constituting a determinate actual bios out of the indefinite potentialities of zoe, form-of-life exemplifies the power of rendering actual and determinate forms inoperative or destitute. Rather than attempt to devise a ‘proper’ form of life, Agamben seeks to free life from the gravity of all tasks or vocations imposed on it by privileged forms. W…
Area‐Selective Atomic Layer Deposition on Functionalized Graphene Prepared by Reversible Laser Oxidation
2022
Publisher Copyright: © 2022 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH. Area-selective atomic layer deposition (ALD) is a promising “bottom-up” alternative to current nanopatterning techniques. While it has been successfully implemented in traditional microelectronic processes, selective nucleation of ALD on 2D materials has so far remained an unsolved challenge. In this article, a precise control of the selective deposition of ZnO on graphene at low temperatures (<250 °C) is demonstrated. Maskless femtosecond laser writing is used to locally activate predefined surface areas (down to 300 nm) by functionalizing graphene to achieve excellent ALD selectivity (up to…
Computational modelling of boron nitride nanostructures based on density-functional tight-binding
2014
Boorinitridin (BN) nanorakenteet ovat sekä rakenteellisesti että lujuusominaisuuksiensa puolesta hyvin samankaltaisia vastaavien hiilirakenteiden kanssa. Suurimpana erona on BN:n sähköinen eristävyys kun taas hiilirakenteet ovat johteita tai puolijohteita. BN onkin hyvin lupaava nanomateriaali ja sille on odotettavissa sovelluksia muun muassa muiden nanorakenteiden suojaajana ja komposiittimateriaalien nanokudosaineena. BN:n nanorakenteiden ominaisuuksia tutkitaan laskennallisesti yleensä joko tiheysfunktionaaliteorialla (DFT) tai tiukan sidoksen (TB) malleilla. Ensin mainittu on tarkka mutta laskennallisesti vaativa, kun taas jälkimmäinen on laskennallisesti kevyt mutta epätarkka. Tässä ty…
Plasmonic Resonant Nanoantennas Induce Changes in the Shape and the Intensity of Infrared Spectra of Phospholipids.
2021
Surface enhanced infrared absorption spectroscopic studies (SEIRAS) as a technique to study biological molecules in extremely low concentrations is greatly evolving. In order to use the technique for identification of the structure and interactions of such biological molecules, it is necessary to identify the effects of the plasmonic electric-field enhancement on the spectral signature. In this study the spectral properties of 1,2-Dipalmitoyl-sn-glycero-3 phosphothioethanol (DPPTE) phospholipid immobilized on gold nanoantennas, specifically designed to enhance the vibrational fingerprints of lipid molecules were studied. An AFM study demonstrates an organization of the DPPTE phospholipid in…
Ultrastiff graphene
2021
Graphene has exceptionally high in-plane strength, which makes it ideal for various nanomechanical applications. At the same time, its exceptionally low out-of-plane stiffness makes it also flimsy and hard to handle, rendering out-of-plane structures unstable and difficult to fabricate. Therefore, from an application point of view, a method to stiffen graphene would be highly beneficial. Here we demonstrate that graphene can be significantly stiffened by using a laser writing technique called optical forging. We fabricate suspended graphene membranes and use optical forging to create stable corrugations. Nanoindentation experiments show that the corrugations increase graphene bending stiffn…
Controlling thermal conductance using three-dimensional phononic crystals
2021
Controlling thermal transport at the nanoscale is vital for many applications. Previously, it has been shown that this control can be achieved with periodically nanostructured two-dimensional phononic crystals for the case of suspended devices. Here, we show that thermal conductance can also be controlled with three-dimensional phononic crystals, allowing the engineering of the thermal contact of more varied devices without the need for suspension in the future. We show the experimental results obtained at sub-Kelvin temperatures for two different period three-dimensional crystals and for a bulk control structure. The results show that the conductance can be enhanced with the phononic cryst…
Real-space Wigner-Seitz Cells Imaging of Potassium on Graphite via Elastic Atomic Manipulation
2015
Atomic manipulation in the scanning tunnelling microscopy, conventionally a tool to build nanostructures one atom at a time, is here employed to enable the atomic-scale imaging of a model low-dimensional system. Specifically, we use low-temperature STM to investigate an ultra thin film (4 atomic layers) of potassium created by epitaxial growth on a graphite substrate. The STM images display an unexpected honeycomb feature, which corresponds to a real-space visualization of the Wigner-Seitz cells of the close-packed surface K atoms. Density functional simulations indicate that this behaviour arises from the elastic, tip-induced vertical manipulation of potassium atoms during imaging, i.e. el…
Flat-band superconductivity in periodically strained graphene : mean-field and Berezinskii–Kosterlitz–Thouless transition
2020
In the search of high-temperature superconductivity one option is to focus on increasing the density of electronic states. Here we study both the normal and s-wave superconducting state properties of periodically strained graphene, which exhibits approximate flat bands with a high density of states, with the flatness tunable by the strain profile. We generalize earlier results regarding a one-dimensional harmonic strain to arbitrary periodic strain fields, and further extend the results by calculating the superfluid weight and the Berezinskii–Kosterlitz–Thouless (BKT) transition temperature T BKT to determine the true transition point. By numerically solving the self-consistency equation, w…