scholarly journals The damping of terahertz acoustic modes in aqueous nanoparticle suspensions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alessio De Francesco ◽  
Luisa Scaccia ◽  
Ferdinando Formisano ◽  
Eleonora Guarini ◽  
Ubaldo Bafile ◽  
...  
Keyword(s):  
Bayesian Analysis ◽  
Relative Concentration ◽  
Acoustic Mode ◽  
Acoustic Damping ◽  
Longitudinal Acoustic ◽  
X Ray ◽  
Acoustic Modes ◽  
X Ray Scattering ◽  
Nanoparticle Suspensions ◽  
Shed Light

AbstractIn this work, we investigate the possibility of controlling the acoustic damping in a liquid when nanoparticles are suspended in it. To shed light on this topic, we performed Inelastic X-Ray Scattering (IXS) measurements of the terahertz collective dynamics of aqueous suspensions of nanospheres of various materials, size, and relative concentration, either charged or neutral. A Bayesian analysis of measured spectra indicates that the damping of the two acoustic modes of water increases upon nanoparticle immersion. This effect seems particularly pronounced for the longitudinal acoustic mode, which, whenever visible at all, rapidly damps off when increasing the exchanged wavevector. Results also indicate that the observed effect strongly depends on the material the immersed nanoparticles are made of.

scholarly journals High frequency acoustic modes in vitreous beryllium fluoride probed by inelastic x-ray scattering

2003 ◽  
Vol 118 (1) ◽  
pp. 311-316 ◽  
Author(s):  
T. Scopigno ◽  
S. N. Yannopoulos ◽  
D. Th. Kastrissios ◽  
G. Monaco ◽  
E. Pontecorvo ◽  
...  
Keyword(s):  
High Frequency ◽  
X Ray ◽  
Acoustic Modes ◽  
X Ray Scattering ◽  
Beryllium Fluoride ◽  
Ray Scattering

Phonon Excitations in Pd40Ni40P20 Bulk Metallic Glass by Inelastic X-Ray Scattering

2016 ◽  
Vol 879 ◽  
pp. 767-772 ◽  
Author(s):  
Shinya Hosokawa ◽  
Masanori Inui ◽  
Yukio Kajihara ◽  
Tetsu Ichitsubo ◽  
Kazuhiro Matsuda ◽  
...  
Keyword(s):  
Dispersion Relation ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Elastic Properties ◽  
Excitation Energies ◽  
Longitudinal Acoustic ◽  
X Ray ◽  
X Ray Scattering ◽  
Transverse Acoustic ◽  
Ray Scattering

To clarify microscopic elastic properties of a Pd40Ni40P20 bulk metallic glass, inelastic X-ray scattering (IXS) experiments were carried out using high-resolution IXS spectrometer installed at BL35XU/SPring-8. Clear longitudinal acoustic (LA) excitation modes are observed in the whole momentum transfer Q range up to ~22 nm-1. The microscopic sound velocity of the LA modes obtained from the Q → 0 limit of the dispersion relation is about 12% faster than the macroscopic value, suggesting the microscopic heterogeneity in the elastic properties of this BMG. In addition, transverse acoustic (TA) modes can be deduced from a detailed analysis of the IXS spectra. The microscopic Poisson’s ratio obtained from the ratio of the excitation energies of the TA and LA modes is 0.47 ± 0.04, larger than the macroscopic value of 0.40. Thus, the fragile nature of this BMG already found in the macroscopic sense is much enhanced in the microscopic view.

scholarly journals ATP/ADP modulates gp16–pRNA conformational change in the Phi29 DNA packaging motor

2019 ◽  
Vol 47 (18) ◽  
pp. 9818-9828 ◽  
Author(s):  
Rujie Cai ◽  
Ian R Price ◽  
Fang Ding ◽  
Feifei Wu ◽  
Ting Chen ◽  
...  
Keyword(s):  
Small Angle ◽  
3D Models ◽  
Dna Packaging ◽  
Conformation Change ◽  
Packaging Process ◽  
X Ray ◽  
X Ray Scattering ◽  
Chemical Probing ◽  
Dna Packaging Motor ◽  
Shed Light

Abstract Packaging of phage phi29 genome requires the ATPase gp16 and prohead RNA (pRNA). The highly conserved pRNA forms the interface between the connector complex and gp16. Understanding how pRNA interacts with gp16 under packaging conditions can shed light on the molecular mechanism of the packaging motor. Here, we present 3D models of the pRNA–gp16 complex and its conformation change in response to ATP or ADP binding. Using a combination of crystallography, small angle X-ray scattering and chemical probing, we find that the pRNA and gp16 forms a ‘Z’-shaped complex, with gp16 specifically binds to pRNA domain II. The whole complex closes in the presence of ATP, and pRNA domain II rotates open as ATP hydrolyzes, before resetting after ADP is released. Our results suggest that pRNA domain II actively participates in the packaging process.

Self-Sustained Instabilities in an Annular Combustor Coupled by Azimuthal and Longitudinal Acoustic Modes

2013 ◽  
Author(s):  
Jean-Francois Bourgouin ◽  
Daniel Durox ◽  
Jonas P. Moeck ◽  
Thierry Schuller ◽  
Sébastien Candel
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
High Speed ◽  
High Amplitude ◽  
Acoustic Mode ◽  
Azimuthal Mode ◽  
Longitudinal Acoustic ◽  
Acoustic Modes ◽  
Annular Combustor

Annular combustors may give rise to various types of combustion instabilities. Some of the resulting oscillations coupled by transverse acoustic modes are commonly observed in practice and their suppression or reduction is an important issue which needs to be considered. The present study is carried out in a system comprising an annular plenum feeding 16 swirling injectors confined by two cylindrical quartz tubes opened to the atmosphere. Calculations based on a Helmholtz solver provide a suitable estimate of frequencies observed experimentally and reveal the modal structure corresponding to the longitudinal and transverse oscillations. High speed images obtained under reactive conditions are then processed to extract the structure of heat release rate perturbations and match this structure with that of the coupling acoustic mode. It is found that the transverse instability is coupled by a first azimuthal mode which is characterized by a time varying spin ratio. This index gives the respective levels of rotating components in the azimuthal mode. Another instability arising at a lower frequency is coupled by a longitudinal acoustic mode giving rise to high-amplitude oscillations in heat release rate in which most of the flames (but not all) are synchronized and in phase with the pressure perturbation.

scholarly journals Solvent-mediated conductance increase of dodecanethiol-stabilized gold nanoparticle monolayers

2016 ◽  
Vol 7 ◽  
pp. 2057-2064 ◽  
Author(s):  
Patrick A Reissner ◽  
Jean-Nicolas Tisserant ◽  
Antoni Sánchez-Ferrer ◽  
Raffaele Mezzenga ◽  
Andreas Stemmer
Keyword(s):  
Gold Nanoparticle ◽  
Organic Molecules ◽  
Pure Ethanol ◽  
X Ray ◽  
X Ray Scattering ◽  
Average Factor ◽  
Respective Contribution ◽  
Conductance Increase ◽  
Shed Light

Gold nanoparticle monolayers provide convenient templates to study charge transport in organic molecules beyond single junction techniques. Conductance is reported to increase by several orders of magnitude following immersion of alkanethiol-stabilized gold nanoparticle monolayers in a solution containing conjugated thiol-functionalized molecules. Typically, this observation is attributed to molecular exchange. Less attention has been paid to the role of the solvent alone. Here, we report on an increase in conductance of dodecanethiol-stabilized gold nanoparticle monolayers on Si/SiO2 by an average factor of 36 and 22 after immersion in pure ethanol (EtOH) and tetrahydrofuran (THF), respectively. Analysis by scanning electron microscopy (SEM) and small-angle X-ray scattering (SAXS) reveals a solvent-induced decrease in lattice constant of close-packed monolayers. We compare the conductance of the monolayer after molecular exchange with two different oligophenylenes to shed light on the respective contribution of the solvent-induced structural change and the molecular exchange itself on the conductance increase.

Acoustic modes in the network glass Li 2 O-2B 2 O 3 : new evidence from inelastic X-ray scattering

2002 ◽  
Vol 82 (2) ◽  
pp. 243-249 ◽  
Author(s):  
Aleksandar Matic ◽  
Lars Börjesson ◽  
Giulio Monaco ◽  
Dennis Engberg ◽  
Claudio Masciovecchio
Keyword(s):  
X Ray ◽  
Acoustic Modes ◽  
X Ray Scattering ◽  
Network Glass ◽  
New Evidence ◽  
Ray Scattering

scholarly journals The Terahertz Dynamics of an Aqueous Nanoparticle Suspension: An Inelastic X-ray Scattering Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 860
Author(s):  
Alessio De Francesco ◽  
Luisa Scaccia ◽  
Ferdinando Formisano ◽  
Eleonora Guarini ◽  
Ubaldo Bafile ◽  
...  
Keyword(s):  
Aqueous Suspension ◽  
Pure Water ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Acoustic Mode ◽  
Complete Disappearance ◽  
Nanoparticle Suspension ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

We used the high-resolution Inelastic X-ray Scattering beamline of the Advanced Photon Source at Argonne National Laboratory to measure the terahertz spectrum of pure water and a dilute aqueous suspension of 15 nm diameter spherical Au nanoparticles (Au-NPs). We observe that, despite their sparse volume concentration of about 0.5%, the immersed NPs strongly influence the collective molecular dynamics of the hosting liquid. We investigate this effect through a Bayesian inference analysis of the spectral lineshape, which elucidates how terahertz transport properties of water change upon Au-NP immersion. In particular, we observe a nearly complete disappearance of the longitudinal acoustic mode and a mildly decreased ability to support shear wave propagation.

Acoustic modes in the network glass Li2O-2B2O3: New evidence from inelastic X-ray scattering

2002 ◽  
Vol 82 (2) ◽  
pp. 243-249
Author(s):  
Aleksandar Matic ◽  
Lars Börjesson ◽  
Giulio Monaco ◽  
Dennis Elngberg ◽  
Claudio Masciovecchio
Keyword(s):  
X Ray ◽  
Acoustic Modes ◽  
X Ray Scattering ◽  
Network Glass ◽  
New Evidence ◽  
Ray Scattering
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