Results 1 to 10 of about 151,091 (74)

Temperatures in Grains and Plasma [PDF]

EPL, 135 (2021) 36003, 2022
Grains are widely assumed to be characterized by a single temperature -- derived either from the configurational entropy, or employing the kinetic theory. Yet granular media do have two temperatures, $T_g$ and $T$, pertaining to the grains and atoms.
arxiv   +1 more source

Coarse-graining master equation for periodically driven systems [PDF]

Phys. Rev. A 104, 052219 (2021), 2021
We analyze Lindblad-Gorini-Kossakowski-Sudarshan-type generators for selected periodically driven open quantum systems. All these generators can be obtained by temporal coarse-graining procedures, and we compare different coarse-graining schemes. Similar as for undriven systems, we find that a dynamically adapted coarse-graining time, effectively ...
arxiv   +1 more source

Bias sputtering of granular $\text{L1}_0$-FePt films with hexagonal boron nitride grain boundaries [PDF]

Scientific Reports, volume 13, Article number: 11087 (2023), 2023
In this paper, we present an experimental study of $\text{L1}_0$-FePt granular films with crystalline/amorphous boron nitride (BN) grain boundary materials for heat assisted magnetic recording (HAMR). It is found that an adequate RF substrate bias yields the formation of hexagonal boron nitride (h-BN) nanosheets in grain boundaries, facilitating the ...
arxiv   +1 more source

Yielding Transitions and Grain-Size Effects in Dislocation Theory [PDF]

Phys. Rev. E 95, 033004 (2017), 2017
The statistical-thermodynamic dislocation theory developed in previous papers is used here in an analysis of yielding transitions and grain-size effects in polycrystalline solids. Calculations are based on the 1995 experimental results of Meyers et al. for polycrystalline copper under strain-hardening conditions.
arxiv   +1 more source

The driving force governing room temperature grain coarsening in thin gold films [PDF]

Scripta Materialia 130 (2017) 42-45, 2019
Strong room-temperature grain coarsening in gold films on polyimide induced by cyclic uniaxial mechanical strain is demonstrated. Detailed electron backscatter diffraction analysis revealed that, in contrast to the predictions of shear-coupled grain boundary migration model, the grain coarsening is isotropic and coarsened grains do not exhibit any ...
arxiv   +1 more source

Evaporative cooling of icy interstellar grains II. Key parameters [PDF]

A&A 641, A49 (2020), 2020
Context. Evaporative (sublimation) cooling of icy interstellar grains occurs when the grains have been suddenly heated by a cosmic-ray (CR) particle or other process. It results in thermal desorption of icy species, affecting the chemical composition of interstellar clouds. Aims.
arxiv   +1 more source

Initiation and stagnation of room temperature grain coarsening in cyclically strained gold films [PDF]

Acta Materialia 169 (2019) 99-108, 2019
Despite the large number of experiments demonstrating that grains in a metallic material can grow at room temperature due to applied mechanical load, the mechanisms and the driving forces responsible for mechanically induced grain coarsening are still not understood.
arxiv   +1 more source

Davis-Greenstein alignment of oblate spheroidal grains [PDF]

Mon.Not.Roy.Astron.Soc.305:615-630,1999, 1998
We present extensive calculations on the efficiency of grain alignment by the Davis-Greenstein mechanism. We model the grains as oblate spheroids with arbitrary axis ratios. Our description of the grain dynamics includes (i) magnetic dissipation and the inverse process driven by thermal fluctuations in the grain magnetization; (ii) gas-grain collisions
arxiv   +1 more source

The alignment of interstellar dust grains: thermal flipping and the Davis-Greenstein mechanism [PDF]

, 2021
Interstellar dust grains are non-spherical and, in some environments, partially aligned along the direction of the interstellar magnetic field. Numerous alignment theories have been proposed, all of which examine the grain rotational dynamics. In 1999, Lazarian & Draine introduced the important concept of thermal flipping, in which internal relaxation ...
arxiv   +1 more source

Poiseuille flow of soft polycrystals in 2D rough channels [PDF]

Phys. Rev. Lett. 124, 158003 (2020), 2018
Polycrystals are partially ordered solids where crystalline order extends over mesoscopic length scales, namely, the grain size. We study the Poisuielle flow of such materials in a rough channel. In general, similar to yield stress fluids, three distinct dynamical states, namely, flowing, stick-slip and jammed can be observed, with a yield threshold ...
arxiv   +1 more source