1,129 research outputs found
Metal/molecule/metal junction studies of organometallic and coordination complexes; What can transition metals do for molecular electronics?
The Effect of Particle Strength on the Ballistic Resistance of Shear Thickening Fluids
The response of shear thickening fluids (STFs) under ballistic impact has
received considerable attention due to its field-responsive nature. While
efforts have primarily focused on the response of traditional ballistic fabrics
impregnated with fluids, the response of pure STFs to penetration has received
limited attention. In the present study, the ballistic response of pure STFs is
investigated and the effect of fluid density and particle strength on ballistic
performance is isolated. The loss of ballistic resistance of STFs at higher
impact velocities is governed by particle strength, indicating the range of
velocities over which they may provide effective armor solutions.Comment: 4 pages, 4 figure
Synthesis and characterization of [MCl2(PAr3)(2)]-ethylenedioxythiophene copolymers (M = Pd, Pt), made by electropolymerisation of diphenyl(2,2 ',3,3 '-tetrahydro-[5,5 '-bithieno [3,4-b][1,4]dioxin]-7-yl)phosphane (Ph2P[bis-EDOT]) complexes
Metastable states of a flux line lattice studied by transport and Small Angle Neutron Scattering
Flux Lines Lattice (FLL) states have been studied using transport
measurements and Small Angle Neutron Scattering in low T materials. In
Pb-In, the bulk dislocations in the FLL do not influence the transport
properties. In Fe doped NbSe, transport properties can differ after a
Field Cooling (FC) or a Zero Field Cooling (ZFC) procedure, as previously
reported. The ZFC FLL is found ordered with narrow Bragg Peaks and is linked to
a linear V(I) curve and to a superficial critical current. The FC FLL pattern
exhibits two Bragg peaks and the corresponding V(I) curve shows a S-shape. This
can be explained by the coexistence of two ordered FLL slightly tilted from the
applied field direction by different superficial currents. These currents are
wiped out when the transport current is increased.Comment: accepted for publication in Phys. Rev.
Empirically testing <i>Tonnetz</i>, voice-leading, and spectral models of perceived triadic distance
We compare three contrasting models of the perceived distance between root-position major and minor chords and test them against new empirical data. The models include a recent psychoacoustic model called spectral pitch class distance, and two well-established music theoretical models â Tonnetz distance and voice-leading distance. To allow a principled challenge, in the context of these data, of the assumptions behind each of the models, we compare them with a simple âbenchmarkâ model that simply counts the number of common tones between chords. Spectral pitch class and Tonnetz have the highest correlations with the experimental data and each other, and perform significantly better than the benchmark. The voice-leading model performs worse than the benchmark. We suggest that spectral pitch class distance provides a psychoacoustic explanation for perceived harmonic distance and its music theory representation, the Tonnetz. Scores and MIDI files of the stimuli, the experimental data, and the computational models are available in the online supplement
Resonant transport and electrostatic effects in single-molecule electrical junctions
In this contribution we demonstrate structural control over a transport resonance in HS(CH2)n[1,4 âC6H4](CH2)nSH (n = 1, 3, 4, 6) metal-molecule-metal junctions, fabricated and tested using the scanning
tunnelingmicroscopy-based I (z)method. The Breit-Wigner resonance originates from one of the arene Ï-bonding orbitals, which sharpens and moves closer to the contact Fermi energy as n increases. Varying the number of methylene groups thus leads to a very shallow decay of the conductance with the length of the molecule. We demonstrate that the electrical behavior observed here can be straightforwardly rationalized by analyzing the effects caused by the electrostatic balance created at the metal-molecule interface. Such resonances offer future prospects in molecular electronics in terms of controlling charge transport over longer distances, and also in single-molecule conductance switching if the resonances can be externally gatedThis research was supported by the EPSRC (Grant No. EP/H035184/1), by MINECO under Grant No. FIS2013-47328, by the European Union structural funds and the Comunidad de Madrid MAD2D-CM Program under Grant. P2013/MIT-2850, and by Generalitat Valenciana under Grant PROMETEO/2012/011
Why pinning by surface irregularities can explain the peak effect in transport properties and neutron diffraction results in NbSe2 and Bi-2212 crystals?
The existence of a peak effect in transport properties (a maximum of the
critical current as function of magnetic field) is a well-known but still
intriguing feature of type II superconductors such as NbSe2 and Bi-2212. Using
a model of pinning by surface irregularities in anisotropic superconductors, we
have developed a calculation of the critical current which allows estimating
quantitatively the critical current in both the high critical current phase and
in the low critical current phase. The only adjustable parameter of this model
is the angle of the vortices at the surface. The agreement between the
measurements and the model is really very impressive. In this framework, the
anomalous dynamical properties close to the peak effect is due to co-existence
of two different vortex states with different critical currents. Recent neutron
diffraction data in NbSe2 crystals in presence of transport current support
this point of view
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