Search results for "plasma"

Hydrogen plasma induced photoelectron emission from metal surfaces

2018

Low temperature hydrogen plasmas are strong sources of vacuum ultraviolet radiation. The properties of laboratory plasmas can be influenced by surface processes induced by photons with their energies exceeding the surface work function of the wall material. In this work, the plasma induced photoelectron emission has been studied with different ion sources. The emission depends on the mechanical design of the plasma device, plasma heating method and the discharge power (density). Parametric studies include the quantifying of the emission from different metal surfaces, commonly used as plasma facing materials in ion sources, as well as alkali metal covered surfaces. Experimental studies sugges…

Mikroaalloilla lämmitetyn vetyplasman emittoiman valon aiheuttama fotoelektroniemissio metallipinnoilla

2013

Vertex corrections for positive-definite spectral functions of simple metals

2016

We present a systematic study of vertex corrections in the homogeneous electron gas at metallic densities. The vertex diagrams are built using a recently proposed positive-definite diagrammatic expansion for the spectral function. The vertex function not only provides corrections to the well known plasmon and particle-hole scatterings, but also gives rise to new physical processes such as generation of two plasmon excitations or the decay of the one-particle state into a two-particles-one-hole state. By an efficient Monte Carlo momentum integration we are able to show that the additional scattering channels are responsible for the bandwidth reduction observed in photoemission experiments on…

High-Reynolds-number turbulent cavity flow using the lattice Boltzmann method

2018

We present a boundary condition scheme for the lattice Boltzmann method that has significantly improved stability for modeling turbulent flows while maintaining excellent parallel scalability. Simulations of a three-dimensional lid-driven cavity flow are found to be stable up to the unprecedented Reynolds number $\mathrm{Re}=5\ifmmode\times\else\texttimes\fi{}{10}^{4}$ for this setup. Excellent agreement with energy balance equations, computational and experimental results are shown. We quantify rises in the production of turbulence and turbulent drag, and determine peak locations of turbulent production.

Designing a graphics processing unit accelerated petaflop capable lattice Boltzmann solver: Read aligned data layouts and asynchronous communication

2016

The lattice Boltzmann method is a well-established numerical approach for complex fluid flow simulations. Recently, general-purpose graphics processing units (GPUs) have become available as high-performance computing resources at large scale. We report on designing and implementing a lattice Boltzmann solver for multi-GPU systems that achieves 1.79 PFLOPS performance on 16,384 GPUs. To achieve this performance, we introduce a GPU compatible version of the so-called bundle data layout and eliminate the halo sites in order to improve data access alignment. Furthermore, we make use of the possibility to overlap data transfer between the host central processing unit and the device GPU with com…

Measurement of dielectron production in central Pb-Pb collisions at √sNN = 2.76 TeV

2019

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. The first measurement of dielectron (e + e −) production in central (0 – 10 %) Pb – Pb collisions at √sNN=2.76TeV at the LHC is presented. The dielectron invariant-mass spectrum is compared to the expected contributions from hadron decays in the invariant-mass range 0 < mee < 3.5 GeV / c2. The ratio of data and the cocktail of hadronic contributions without vacuum ρ0 is measured in the invariant-mass range 0.15 < mee < 0.7 GeV / c2, w…

The Extracellular δ-Domain is Essential for the Formation of CD81 Tetraspanin Webs

2014

AbstractCD81 is a ubiquitously expressed member of the tetraspanin family. It forms large molecular platforms, so-called tetraspanin webs that play physiological roles in a variety of cellular functions and are involved in viral and parasite infections. We have investigated which part of the CD81 molecule is required for the formation of domains in the cell membranes of T-cells and hepatocytes. Surprisingly, we find that large CD81 platforms assemble via the short extracellular δ-domain, independent from a strong primary partner binding and from weak interactions mediated by palmitoylation. The δ-domain is also essential for the platforms to function during viral entry. We propose that, ins…

Caracterización del viroma en plasma de donantes de sangre

2022

El desarrollo de la metagenómica ha impulsado el descubrimiento de un número notable de nuevas secuencias virales, lo que ha permitido conocer la composición de las comunidades virales de múltiples ambientes, entre los que se incluye el cuerpo humano. El viroma humano se caracteriza por presentar una enorme heterogeneidad, en cada localización corporal existe un ambiente determinado, lo que se refleja en una composición muy diversa de las comunidades de virus y bacterias presentes. En concreto, el plasma sanguíneo se caracteriza por albergar diferentes virus, incluso en individuos aparentemente sanos, como los donantes de sangre. Para caracterizar los virus presentes en muestras de plasma, …

Regulación del volumen plasmático en el ejercicio: papel de la intensidad y la adaptación al entrenamiento.

2016

La función del sistema circulatorio es la de mantener el entorno celular apropiado para el correcto desarrollo y supervivencia de los tejidos, aportando nutrientes, O2, y hormonas, al mismo tiempo que se retiran productos de desecho y CO2 (Guyton and Hall 2006b). Por tanto, el sistema circulatorio juega un papel fundamental en el mantenimiento de la homeostasis (Cannon 1929). Para cumplir esta misión, es fundamental mantener el flujo sanguíneo en todos los tejidos del organismo en función de las necesidades. El sistema circulatorio regula el flujo sanguíneo en todo el cuerpo mediante diversos mecanismos de feedback que modulan el gasto cardíaco (Q), la presión sanguínea y la distribución lo…

The Effect of Electrolytic Solution Composition on the Structure, Corrosion, and Wear Resistance of PEO Coatings on AZ31 Magnesium Alloy

2020

Plasma electrolytic oxidation coatings were prepared in aluminate, phosphate, and silicate-based electrolytic solutions using a soft-sparking regime in a multi-frequency stepped process to compare the structure, corrosion, and wear characteristics of the obtained coatings on AZ31 magnesium alloy. The XRD results indicated that all coatings consist of MgO and MgF2, while specific products such as Mg2SiO4, MgSiO3, Mg2P2O7, and MgAl2O4 were also present in specimens based on the selected solution. Surface morphology of the obtained coatings was strongly affected by the electrolyte composition. Aluminate-containing coating showed volcano-like, nodular particles and craters distributed over the …