Search results for "Magnet"
showing 10 items of 15436 documents
Phonons in MoSe2/WSe2 van der Waals heterobilayer
2021
We report first-principles calculations of the structural and vibrational properties of the synthesized two-dimensional van der Waals heterostructures formed by single-layers dichalcogenides MoSe2 and WSe2. We show that, when combining these systems in a periodic two-dimensional heterostructures, the intrinsic phonon characteristics of the free-standing constituents are to a large extent preserved but, furthermore, exhibit shear and breathing phonon modes that are not present in the individual building blocks. These peculiar modes depend strongly on the weak vdW forces and has a great contibution to the thermal properties of the layered materials. Besides these features, the departure of fl…
Hadronic light-by-light contribution to $(g-2)_\mu$ from lattice QCD with SU(3) flavor symmetry
2020
We perform a lattice QCD calculation of the hadronic light-by-light contribution to $(g-2)_\mu$ at the SU(3) flavor-symmetric point $m_\pi=m_K\simeq 420\,$MeV. The representation used is based on coordinate-space perturbation theory, with all QED elements of the relevant Feynman diagrams implemented in continuum, infinite Euclidean space. As a consequence, the effect of using finite lattices to evaluate the QCD four-point function of the electromagnetic current is exponentially suppressed. Thanks to the SU(3)-flavor symmetry, only two topologies of diagrams contribute, the fully connected and the leading disconnected. We show the equivalence in the continuum limit of two methods of computin…
Feedback Linearization Based Nonlinear Control of SynRM Drives Accounting for Self- and Cross-Saturation
2022
This article proposes a nonlinear controller based on feedback linearization (FL) for synchronous reluctance motor (SynRM) drives which takes into consideration the magnetic saturation. The proposed nonlinear FL control based control technique has been developed starting from the theoretical definition of an original dynamic model of the SynRM taking into consideration both the self- and the cross-saturation effects. Such a control technique permits the dynamics of both the speed and axis flux loops to be maintained constant independently from the load and the saturation of the iron core in both constant flux and variable direct axis flux operating conditions. Finally, sensitivity of the pe…
Synchrotron x-ray transmission measurements and modeling of filters investigated for Athena
2020
International audience; Advanced Telescope for High-Energy Astrophysics is a large-class astrophysics space mission selected by the European Space Agency to study the theme "Hot and Energetic Universe." The mission essentially consists of a large effective area x-ray telescope and two detectors: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager (WFI). Both instruments require filters to shield from out-of-band radiation while providing high transparency to x-rays. The mission is presently in phase B; thus, to consolidate the preliminary design, investigated filter materials need to be properly characterized by experimental test campaigns. We report results from high-resolution…
Towards Controlled Synthesis of Water-Soluble Gold Nanoclusters : Synthesis and Analysis
2019
Water-soluble gold nanoclusters with well-defined molecular structures and stability possess particular biophysical properties making them excellent candidates for biological applications as well as for fundamental spectroscopic studies. The currently existing synthetic protocols for atomically monodisperse thiolate-protected gold nanoclusters (AuMPCs) have been widely expanded with organothiolates, yet the direct synthesis reports for water-soluble AuMPCs are still deficient. Here, we demonstrate a wet-chemistry pH-controlled synthesis of two large water-soluble nanoclusters utilizing p-mercaptobenzoic acid (pMBA), affording different sizes of plasmonic AuMPCs on the preparative scale (∼7 …
An Easy Route Towards Regioselectively Difunctionalized Cyclens and New Cryptands.
2006
Reductive amination of various aldehydes with cyclen represents a very convenient method for the synthesis of a wide range of 1,7-difunctionalized cyclens, as well as new cryptands.
Sähkömagneettisen sironnan numeerinen simulointi
2004
The nonstationary Maxwell system in domains with edges and conical points
2005
Sergey Matyukevich on väitöskirjassaan tutkinut Maxwell-yhtälöä alueilla, joilla on kartiomaisia kärkiä ja teräviä särmiä. Erityisen huomion kohteena tutkimuksessa oli tutkia yhtälön ratkaisujen käyttäytymistä lähellä ns. singulaaripisteitä, joita epäsileät reunat aiheuttavat. Tutkimuksessa Matyukevich on johtanut ratkaisuille eksplisiittisiä, asymptoottisia laajennuksia alueen kartiomaisten kärkien ja terävien särmien ympäristössä.Tutkimuksen tuloksilla on merkitystä siinä, että niitä voidaan soveltaa useiden ei-stationaaristen sähkömagnetiikan yhtälöiden matemaattisessa ja numeerisessa analysoinnissa epäsileillä alueilla. We study the nonstationary Maxwell system in domains with conical p…
High performance microbolometers and microcalorimeters: from 300 K to 100 mK
2003
Lukion sähköopin ja sähkömagnetismin opetusmateriaalien tietorakenteiden kartoittaminen ja kehitysehdotusten etsiminen
2011
Sähköopin ja sähkömagnetismin aihekokonaisuudet ovat lukion kurssien tuntimääriin nähden raskaita ja tietoa on hyvin paljon. Työn tavoitteena oli selvittää voisiko lukion sähköopin ja sähkömagnetismin tietorakenteita ja samalla koko aihekokonaisuuksia keventää. Työssä tarkastellaan käsitekarttoja käyttäen huomattavan laajoja aihekokonaisuuksia, tarkoituksena luoda pohjaa opintokokonaisuuksien edelleenkehittämiselle. Kokonaisuutena työ tarjoaa yksittäiselle opettajalle ideoita oman opetuksensa päivittämiseen ja laajemmin mahdollisuuksia oppimateriaalien kehittämiselle. Työn laaja tarkastelupohja lisää tulosten soveltamismahdollisuuksia. Tietorakenteita pyrittiin kartoittamaan koottujen käsit…