Strong variation of global-transport properties in chaotic ensembles

<div>Molecules in gas and liquid states, as well as in solution, exhibit significant and random Brownian motion. Molecules in the solid-state, although strongly immobilized, can still exhibit significant intramolecular dynamics. However, in most framework materials, these intramolecular dynamics are driven by temperature, and therefore are neither controlled nor spatially or temporarily aligned. In recent years, several examples of molecular machines that allow for a stimuli-responsive control of dynamical motion, such as rotation, have been reported.</div><div><br></div><div>In this contribution, we investigate the local and global properties of a Lennard-Jones (LJ) fluid surrounding a molecular motor and consider the influence of cooperative and non-directional rotation for a molecular motor-containing pore system. This study uses classical molecular dynamics simulations to describe a minimal model, which was developed to resemble known molecular motors. The properties of an LJ liquid surrounding an isolated molecular mo-tor remain mostly unaffected by the introduced rotation. We then considered an arrangement of motors within a one-dimensional pore. Changes in diffusivity for pore sizes approaching the length of the rotor were observed, resulting from rotation of the motors. We also considered the influence of cooperative motor directionality on the directional transport properties of this con-fined fluid. Importantly, we discovered that specific unidirectional rotation of altitudinal motors can produce directed diffusion.</div><div><br></div><div>This study provides an essential insight into molecular machine-containing frameworks, highlighting the specific structural arrangements that can produce directional mass transport.</div>

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Cooperative and synchronized rotation in motorized porous frameworks: impact on local and global transport properties of confined fluids

Faraday Discussions ◽

10.1039/d0fd00016g ◽

2021 ◽

Cited By ~ 3

Author(s):

Jack D. Evans ◽

Simon Krause ◽

Ben L. Feringa

Keyword(s):

Transport Properties ◽

Molecular Motors ◽

Specific Rotation ◽

Confined Fluids ◽

Directed Diffusion ◽

Global Transport

Simulations reveal the influence of rotating molecular motors and the importance of orientation and directionality for altering the transport properties of fluids. This has outlined that motors with specific rotation can generate directed diffusion.

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Some global transport properties of polysulfone capillary UF membranes

Journal of Membrane Science ◽

10.1016/0376-7388(94)80046-4 ◽

1994 ◽

Vol 90 (1-2) ◽

pp. 191-195

Author(s):

B. Dutré ◽

G. Trägårdh

Keyword(s):

Transport Properties ◽

Global Transport ◽

Uf Membranes

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Cooperative and Synchronized Rotation in Motorized Porous Frameworks: Impact on Local and Global Transport Properties of Confined Fluids

10.26434/chemrxiv.11708844 ◽

2020 ◽

Author(s):

Jack D. Evans ◽

Simon Krause ◽

Ben L. Feringa

Keyword(s):

Transport Properties ◽

Molecular Motors ◽

Molecular Motor ◽

Stimuli Responsive ◽

Intramolecular Dynamics ◽

Directed Diffusion ◽

Framework Materials ◽

Global Transport ◽

Dynamics Simulations ◽

Liquid States

<div>Molecules in gas and liquid states, as well as in solution, exhibit significant and random Brownian motion. Molecules in the solid-state, although strongly immobilized, can still exhibit significant intramolecular dynamics. However, in most framework materials, these intramolecular dynamics are driven by temperature, and therefore are neither controlled nor spatially or temporarily aligned. In recent years, several examples of molecular machines that allow for a stimuli-responsive control of dynamical motion, such as rotation, have been reported.</div><div><br></div><div>In this contribution, we investigate the local and global properties of a Lennard-Jones (LJ) fluid surrounding a molecular motor and consider the influence of cooperative and non-directional rotation for a molecular motor-containing pore system. This study uses classical molecular dynamics simulations to describe a minimal model, which was developed to resemble known molecular motors. The properties of an LJ liquid surrounding an isolated molecular mo-tor remain mostly unaffected by the introduced rotation. We then considered an arrangement of motors within a one-dimensional pore. Changes in diffusivity for pore sizes approaching the length of the rotor were observed, resulting from rotation of the motors. We also considered the influence of cooperative motor directionality on the directional transport properties of this con-fined fluid. Importantly, we discovered that specific unidirectional rotation of altitudinal motors can produce directed diffusion.</div><div><br></div><div>This study provides an essential insight into molecular machine-containing frameworks, highlighting the specific structural arrangements that can produce directional mass transport.</div>

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Microstructures and transport properties: A comparison between grain boundaries artificially produced in YBa2Cu3Ov bicrystal thin films and bulk crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166105 ◽

1996 ◽

Vol 54 ◽

pp. 728-729

Author(s):

X.F. Zhang ◽

V.R. Todt ◽

D.J. Miller ◽

M. St. Louis-Weber ◽

J. Talvacchio

Keyword(s):

Thin Films ◽

Transport Properties ◽

Thin Film Deposition ◽

Film Deposition ◽

Bulk Crystals ◽

Transmission Electron ◽

Electromagnetic Measurements ◽

Global Transport ◽

Film Deposition Rate ◽

Microstructural Studies

In order to establish the link between grain boundary (GB) structures and transport properties in superconducting materials, electromagnetic measurements and detailed microstructural studies of carefully prepared GBs are required. Frequently, artificially induced GBs prepared by thin film deposition onto bicrystal substrates are used for such studies. Recently, transmission electron microscopy (TEM) studies have revealed a meandering configuration for GBs in YBa2Cu3Oy (YBCO) thin films grown on [001] tilt SrTiO3 bicrystal substrates (Fig. la). The deviation of the meandering GBs away from the underlying substrate GBs varies from a few tens to hundreds of nanometers. We have demonstrated that the magnitude of the meander in terms of amplitude and wavelength can be reduced by lowering the film deposition rate. The meandering GBs were shown to consist of various straight facets which are a few tens to hundreds of nanometers in length. It is possible that the various segments have very different current transport behavior due to a variable misfit dislocation density. Thus, an unambiguous correlation between the microstructure and global transport properties is difficult to attain.

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Spectroscopic Diagnostics of Tokamaks

International Astronomical Union Colloquium ◽

10.1017/s0252921100107638 ◽

1988 ◽

Vol 102 ◽

pp. 165-174

Author(s):

C. de Michelis

Keyword(s):

Transport Properties ◽

Power Losses ◽

Spectroscopic Diagnostics ◽

Important Concern

AbstractImpurities being an important concern in tokamaks, spectroscopy plays a key role in their understanding. Techniques for the evaluation of concentrations, power losses and transport properties are surveyed, and a few developments are outlined.

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Structure and Orientation of As Precipitates in LT-MBE Grown GaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100088816 ◽

1991 ◽

Vol 49 ◽

pp. 900-901 ◽

Cited By ~ 1

Author(s):

Alain Claverie ◽

Zuzanna Liliental-Weber

Keyword(s):

Transport Properties ◽

Layer Thickness ◽

Growth Temperature ◽

Low Temperatures ◽

Lattice Parameter ◽

Crystalline Quality ◽

Insulating Properties ◽

Lt Gaas

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.

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