Search results for "ACOUSTIC"

Spin transport across antiferromagnets induced by the spin Seebeck effect

2018

For prospective spintronics devices based on the propagation of pure spin currents, antiferromagnets are an interesting class of materials that potentially entail a number of advantages as compared to ferromagnets. Here, we present a detailed theoretical study of magnonic spin current transport in ferromagnetic-antiferromagnetic multilayers by using atomistic spin dynamics simulations. The relevant length scales of magnonic spin transport in antiferromagnets are determined. We demonstrate the transfer of angular momentum from a ferromagnet into an antiferromagnet due to the excitation of only one magnon branch in the antiferromagnet. As an experimental system, we ascertain the transport acr…

Phase transitions in Ag-based solid electrolytes as detected by thermosonimetry

2001

Abstract Observations of the acoustic emission accompanying the solid–solid (polymorphic) phase changes in silver iodide and silver chalcogenides were performed. It has been found that the temperature dependencies of both the number of acoustic events and their counting rate, registered when heating the investigated materials, display distinct anomalies at the temperature corresponding to the polymorphic phase transition occurring in a given substance. The phase transition temperatures determined from the position of these anomalies agree well with the results of control DSC measurements, as well as with the literature data on the temperatures of the transition of investigated materials to …

Detecting gravitational waves from cosmological phase transitions with LISA: an update

2020

MC was funded by the Royal Society under the Newton International Fellowship program. GD would like to thank CNPq (Brazil) for financial support. MH was supported by the Science and Technology Facilities Council (grant number ST/P000819/1), and the Academy of Finland (grant number 286769). SJH was supported by the Science and Technology Facilities Council (grant number ST/P000819/1). The work of JK was supported by Department of Energy (DOE) grant DE-SC0019195 and NSF grant PHY-1719642. TK and GS are funded by the Deutsche Forschungsgemeinschaft under Germany's Excellence Strategy - EXC 2121 \Quantum Universe" - 390833306. JMN is supported by Ramon y Cajal Fellowship contract RYC-2017-22986…

Phase Transitions and Electrocaloric Effect in Ca-Modified Na1/2Bi1/2TiO3–SrTiO3–PbTiO3Solid Solutions

2014

Influence of carbenoxolone on the anticonvulsant efficacy of conventional antiepileptic drugs against audiogenic seizures in DBA/2 mice

2004

Carbenoxolone, the succinyl ester of glycyrrhetinic acid, is an inhibitor of 11beta-hydroxy steroid dehydrogenase and gap junctional intercellular communication. It is currently used in clinical treatment of ulcer diseases. Systemic administration of carbenoxolone (1-40 mg/kg, intraperitoneally (i.p.)) was able to produce a dose-dependent decrease in DBA/2 audiogenic seizure severity score. Glycyrrhizin, an analogue of carbenoxolone inactive at the gap-junction level, was unable to affect audiogenic seizures at doses up to 30 mg/kg. In combination with conventional antiepileptic drugs, carbenoxolone, 0.5 mg/kg, i.p., which per se did not significantly affect the occurrence of audiogenic sei…

BODIPY - phosphane - gold complexes : towards the elaboration of optical theranostics

2015

This work describes new anticancer agents that could be detected by optical imaging, namely optical theranostics.After a first chapter describing the context of cancer imaging and therapy, a second chapter describes a first series of BODIPY-phosphine-gold theranostics, the synthesis of which has been optimized (less steps, shortening the reaction time, scale up). Their conjugation with biomolecules (glucose, peptide) has been achieved by developing a simple and efficient method that leads to the coupling between the gold atom of the probe and the thiol of the biomolecule (modified or not), leading to a gold sulfur bound. Hence, it makes the biovectorization of the probes possible in order t…

A combined theoretical and experimental determination of the electronic spectrum of acetone

1996

A combined ab initio and experimental investigation has been performed of the main features of the electronic spectrum of acetone. Vertical transition energies have been calculated from the ground to the ny→π∗, π→π∗, σ→π∗, and the n=3 Rydberg states. In addition, the 1A1 energy surfaces have been studied as functions of the CO bond length. The 1A1 3p and 3d states were found to be heavily perturbed by the π→π∗ state. Resonant multiphoton ionization and polarization‐selected photoacoustic spectra of acetone have been measured and observed transitions were assigned on internal criteria. The calculated vertical transition energies to the ny→π∗ and all Rydberg states were found to be in agreeme…

Selective Excitation of Guided Waves into Bone Phantoms by a Time-Delayed Laser Diode Array

2012

We excite selectively the Ao and So plate mode into an acrylic bone phantom using a laser diode array. This is done by controlling the time delay between the signals driving the array elements. Selective mode generation is important because it can potentially increase the sensitivity of in vivo osteoporosis screening.

Photo-acoustic phase-delayed excitation of guided waves in coated bone phantoms

2013

Photo-acoustic skeletal quantitative ultrasound enables assessment of the fundamental flexural guided wave (FFGW) propagating in bone. This mode, consistent with the F(1,1) tube mode can now be measured through a coating of soft tissue. Interference due to ultrasound propagation in the soft tissue surrounding the bone is reduced by using phase-delayed ultrasound excitation. Photo-acoustic phase-delayed excitation was done on five axisymmetric bone phantoms (1-5 mm wall thickness), coated by a 5 mm thick soft-tissue mimicking layer. A fiber head comprising a linear array of four optical fibers (400 μm diameter), illuminated by pulsed laser diodes (905 nm wavelength) generated ultrasound. Thi…

Ultrasonic Guided Wave Inspection of Bonded Lap Joints: Noncontact Method and Photoelastic Visualization

2001

The main topic of this paper is the nondestructive inspection of adhesively bonded lap joints by using ultrasonic guided (plate) waves. A noncontact, couplant-free method that employs capacitive air-coupled transducers is demonstrated for the inspection of thin aluminum joints with dimensions typical of aircraft fuselage and wing panels. Two types of bond defects, disbonded regions and regions of poorly cured (low-cohesive-strength) adhesive, are successfully detected by measuring the amplitude decrease of selected plate waves leaking from one adherend to the other one through the bondline. It is shown that proper choice of the vibrating mode structure, in terms of cross-sectional displacem…