22 research outputs found
Phase-Dependent Electronic Specific Heat in Mesoscopic Josephson Junctions
We study the influence of superconducting correlations on the electronic
specific heat in a diffusive superconductor-normal metal-superconductor
Josephson junction. We present a description of this system in the framework of
the diffusive-limit Green's function theory, taking into account finite
temperatures, phase difference as well as junction parameters. We find that
proximity effect may lead to a substantial deviation of the specific heat as
compared to that in the normal state, and that it can be largely tuned in
magnitude by changing the phase difference between the superconductors. A
measurement setup to confirm these predictions is also suggested.Comment: 4+ pages, 4 figure
Enhanced Interfacial Thermal Conductance between Charged Nanoparticle and Aqueous Electrolyte
Heat transfer through the interface between a metallic nanoparticle and an
electrolyte solution, has great importance in a number of applications, ranging
from nanoparticle-based cancer treatments to nanofluids and solar energy
conversion devices. However, the impact of surface charge and the dissolved
ions on heat transfer has been scarcely explored so far. In this study, we
compute the interface thermal conductance between hydrophilic and hydrophobic
charged gold nanoparticles immersed in an electrolyte using equilibrium
molecular dynamics simulations. Compared with an uncharged nanoparticle, we
report a threefold increase of the Kapitza conductance for a nanoparticle
surface charge +2 e/nm2. This enhancement is shown to be approximately
independent of surface wettability, charge spatial distribution, and salt
concentration. This allows us to express the Kapitza conductance enhancement in
terms of surface charge density on a master curve. Finally, we interpret the
increase of the Kapitza conductance as a combined result of a shift in the
water density distribution toward the charged nanoparticle and an accumulation
of the counter-ions around the nanoparticle surface which increase the
Coulombic interaction between the liquid and the charged nanoparticle
Influence of interface transmissivity and inelastic scattering on the electronic entropy and specific heat of diffusive SNS Josephson junctions
We study theoretically the electronic entropy and specific heat in diffusive
superconductor-normal metal-superconductor (SNS) Josephson junctions. In
particular, we consider the influence of non-idealities occurring in an actual
experiment, such as the presence of barriers at the NS interfaces, the
spin-flip and inelastic scattering in the N region and quasiparticle subgap
states in the superconductors. We find that spin-flip and inelastic scattering
do not have, for typical parameters values, a large effect. On the contrary,
the presence of barriers suppresses the superconducting correlations in the N
region, with the consequence that the entropy and the specific heat get reduced
eventually to those in the absence of superconductivity for opaque interfaces.
Finally we suggest an experiment and check that it is possible, under realistic
conditions, to measure the dependence of electronic specific heat on the phase
difference between the superconductors.Comment: 8 pages, 10 color figure
Crack formation and prevention in colloidal drops
Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticlesopen0
Magnonic transport of an antiferromagnetic chain at the transfer matrix approach
In this paper, we study the magnonic transport properties of an antiferromagnetic chain that is connected to two semi-infinite ferromagnetic leads by using the transfer matrix approach. The antiferromagnetic chain is assumed to be located in a magnonic dissipative environment when an external magnetic field is applied to it. We improved the model in a way that the numerical calculations are rapidly done. In the following, we perform the numerical calculations to obtain the magnonic transmission coefficient and density of states of a multi-atomic antiferromagnetic chain as an illustrative example and we present its results in detail, in the presence of magnetic field and magnonic dissipative forces. Controlling of the resonance region width and the number of peaks in magnonic conductance spectra by variation of the magnetic field amount, the length of the chain, and the magnetic parameters of the system are discussed
Effects of Ply Orientations and Stacking Sequences on Impact Response of Pineapple Leaf Fibre (PALF)/Carbon Hybrid Laminate Composites
This study investigated the impact response behaviours of pineapple leaf fibre (PALF)/carbon hybrid laminate composites for different ply orientations and stacking sequences. The laminates were manufactured using a vacuum infusion approach with various stacking sequences and ply orientations classified as symmetric quasi-isotropic, angle-ply symmetric, and cross-ply symmetric. The laminates were analysed using an IMATEK IM10 drop weight impact tester with an increment of 5 J until the samples were perforated. This investigation reveals that the overall impact properties of PALF and carbon as reinforcements were improved by a beneficial hybridised effect. The laminates with an exterior carbon layer can withstand high impact energy levels up to 27.5 J. The laminate with different stacking sequences had a lower energy transfer rate and ruptured at higher impact energy. The laminates with ply orientations of [0°/90°] and [±45°]8 exhibited 10% to 30% better energy absorption than those with ply orientations of [±45°2, 0°/90°2]s and [0°/90°2, ±45°2]s due to energy being readily transferred within the same linear ply orientation. Through visual inspection, delamination was observed to occur at the interfaces of different stacking sequences and ply orientations