Search results for "rake"

Passion and Alienation : Women as Students of Philosophy

2022

Creation of ordered 3D tubes out of DNA origami lattices

2023

Funding Information: Funding from the Jane and Aatos Erkko Foundation (J.J.T. and A.K./M.V.-R.) and the Academy of Finland (#330584 and #350797 J.J.T./#308992 A.K. and A.K.N./#330896 M.V.-R.) is gratefully acknowledged. The authors also acknowledge the provision of facilities and technical support by Aalto University at OtaNano - Nanomicroscopy Center (Aalto-NMC). Publisher Copyright: © 2023 The Royal Society of Chemistry. Hierarchical self-assembly of nanostructures with addressable complexity has been a promising route for realizing novel functional materials. Traditionally, the fabrication of such structures on a large scale has been achievable using top-down methods but with the cost of…

Elongation and plasmonic activity of embedded metal nanoparticles following heavy ion irradiation

2023

Shape modification of embedded nanoparticles by swift heavy ion (SHI) irradiation is an effective way to produce nanostructures with controlled size, shape, and orientation. In this study, randomly oriented gold nanorods embedded in SiO2 are shown to re-orient along the ion beam direction. The degree of orientation depends on the irradiation conditions and the nanorod's initial size. SHI irradiation was also applied to modify spherical metallic nanoparticles embedded in Al2O3. The results showed that they elongate due to the irradiation comparably to those embedded in SiO2. Metallic nanostructures embedded in dielectric matrices can exhibit localized surface plasmon (LSP) modes. The elongat…

Size dependent swift heavy ion induced Au nanoparticle elongation in SiO2 matrix

2022

The elongation of spherical Au nanoparticles embedded in SiO2 under swift heavy ion (SHI) irradiation is an extensively studied phenomenon. The use of a TEM grid as a substrate facilitates the identification of the same nanoparticle before and after the irradiation. Since the underdensification of SiO2 inside the ion track plays a key role, the elongation is sensitive to the matrix material properties. Therefore, we studied the elongation process of SHI irradiated Au spherical nanoparticles of various diameters (5–80 nm) embedded either in atomic layer deposition (ALD) or plasma-enhanced chemical vapor deposition (PECVD) SiO2. The results show that a different elongation ratio is achieved d…

Effective medium theory for the low-temperature heat capacity of a metasolid plate

2023

Nanopatterning can be used to strongly control the thermal properties of solids, but theoretical understanding relies often on complex numerical simulations. Here, an analytical theory is derived for the low temperature heat capacity of a nanopatterned phononic crystal plate, focusing on the geometry of a square lattice of cylindrical holes in an isotropic matrix material. Its quasistatic elastic properties were studied using an anisotropic effective medium theory, that is, considering it as a homogenized metasolid. The effective elastic parameters can then be used as an input for an anisotropic plate theory, yielding analytical expressions for the dispersion relations of the three lowest p…

Periodic nanostructures for thermal engineering applications

2014

Manufacturing of graphene nanodisks for surface plasmon measurements

2017

Grafeeni on ilmestynyt tieteen rintamalle kovalla ryminällä vasta viimeisen 13 vuoden aikana, mutta on jo nyt yksi mielenkiintoisimmista tutkimuskohteista, jolla voisi olla lukuisia sovelluksia tulevaisuudessa. Grafeeni on ilmestynyt myös plasmoniikan tutkimuskohteeksi sen lukuisten ainutlaatuisten sähköisten ja optisten ominaisuuksien takia ja sen ominaisuuksien muokattavuuden helppouden takia. Grafeeni voisi mahdollisesti korvata yleisesti käytössä olleet jalot metallit kuten kullan ja hopean pintaplasmonien tuotossa ja tutkimuksessa ja voisi johtaa uudenlaiseen valon kontrollointiin nanoskaalassa ja optiikan ja elektroniikan yhdistämiseen tässä pienessä mittakaavassa. Tässä työssä tavoit…

Conduction properties of semiconductive multiwalled carbon nanotubes

2022

AbstractWe have undertaken low-temperature conduction measurements on arc-discharge synthesized, semiconducting multiwalled carbon nanotubes (MWNT). The diameters of these are in the range 2.5–10 nm, corresponding to the sizes just above single-walled carbon nanotubes (SWNT), up to middle-sized MWNTs. The energy gap, inversely related to the diameter, varies strongly in this range, and consequently there is a strong dependence of the transport on tube diameter. Certain transport characteristics are much alike those found in SWNTs, such as the ON-state resistance and Coulomb blockade. However, the transport gap has a more complex behavior than the corresponding one in semiconducting SWNTs, a…

Globally Optimized Equilibrium Shapes of Zirconia-Supported Rh and Pt Nanoclusters : Insights into Site Assembly and Reactivity

2019

Metal−support interfaces form an active site for many important catalytic reactions. The modeling of these interfacial sites calls for approximations to set up a structure model, which in turn may significantly have an impact on studied chemistry and obtained atomistic understanding. Herein, we have employed a density functional theory-based genetic approach to obtain globally optimized nanostructures for Rh and Pt clusters on a ZrO2 support. The analysis of the obtained structures shows that Rh clusters take more compact shapes, whereas Pt prefers elongated and low-symmetry structures. We find that metal−oxide perimeter sites are structurally different, presenting varying Pt and Rh coordin…

Atomic scale surface modification of TiO2 3D nano-arrays : plasma enhanced atomic layer deposition of NiO for photocatalysis

2021

Here we report the development of a new scalable and transferable plasma assisted atomic layer deposition (PEALD) process for the production of uniform, conformal and pinhole free NiO with sub-nanometre control on a commercial ALD reactor. In this work we use the readily available nickel precursor nickelocene in conjunction with O2 plasma as a co-reagent (100 W) over a temperature range of 75–325 °C. An optimised growth per cycle of 0.036 nm was obtained at 250 °C with uniform thickness and coverage on scale-up to and including an 6 inch Si wafer (with a 200 nm thermal SiO2 top layer). The bulk characteristics of the NiO thin films were comprehensively interrogated by PXRD, Raman spectrosco…