8,737 research outputs found
Thermal rectification in asymmetric U-shaped graphene flakes
In this paper, we study the thermal rectification in asymmetric U-shaped
graphene flakes by using nonequilibrium molecular dynamics simulations. The
graphene flakes are composed by a beam and two arms. It is found that the heat
flux runs preferentially from the wide arm to the narrow arm which indicates a
strong rectification effect. The dependence of the rectification ratio upon the
heat flux, the length and the width of the beam, the length and width of the
two arms are studied. The result suggests a possible route to manage heat
dissipation in U-shaped graphene based nanoelectronic devices.Comment: 3 pages, 4 figure
Capacity, Fidelity, and Noise Tolerance of Associative Spatial-Temporal Memories Based on Memristive Neuromorphic Network
We have calculated the key characteristics of associative
(content-addressable) spatial-temporal memories based on neuromorphic networks
with restricted connectivity - "CrossNets". Such networks may be naturally
implemented in nanoelectronic hardware using hybrid CMOS/memristor circuits,
which may feature extremely high energy efficiency, approaching that of
biological cortical circuits, at much higher operation speed. Our numerical
simulations, in some cases confirmed by analytical calculations, have shown
that the characteristics depend substantially on the method of information
recording into the memory. Of the four methods we have explored, two look
especially promising - one based on the quadratic programming, and the other
one being a specific discrete version of the gradient descent. The latter
method provides a slightly lower memory capacity (at the same fidelity) then
the former one, but it allows local recording, which may be more readily
implemented in nanoelectronic hardware. Most importantly, at the synchronous
retrieval, both methods provide a capacity higher than that of the well-known
Ternary Content-Addressable Memories with the same number of nonvolatile memory
cells (e.g., memristors), though the input noise immunity of the CrossNet
memories is somewhat lower
Nanoelectronic thermometers optimised for sub-10 millikelvin operation
We report the cooling of electrons in nanoelectronic Coulomb blockade
thermometers below 4 mK. Above 7 mK the devices are in good thermal contact
with the environment, well isolated from electrical noise, and not susceptible
to self-heating. This is attributed to an optimised design that incorporates
cooling fins with a high electron-phonon coupling and on-chip electronic
filters, combined with a low-noise electronic measurement setup. Below 7 mK the
electron temperature is seen to diverge from the ambient temperature. By
immersing a Coulomb Blockade Thermometer in the 3He/4He refrigerant of a
dilution refrigerator, we measure a lowest electron temperature of 3.7 mK.Comment: 11 pages, 4 figures. (Fixed fitted saturation T_e on p9
Mathematical Estimation of Logical Masking Capability of Majority/Minority Gates Used in Nanoelectronic Circuits
In nanoelectronic circuit synthesis, the majority gate and the inverter form
the basic combinational logic primitives. This paper deduces the mathematical
formulae to estimate the logical masking capability of majority gates, which
are used extensively in nanoelectronic digital circuit synthesis. The
mathematical formulae derived to evaluate the logical masking capability of
majority gates holds well for minority gates, and a comparison with the logical
masking capability of conventional gates such as NOT, AND/NAND, OR/NOR, and
XOR/XNOR is provided. It is inferred from this research work that the logical
masking capability of majority/minority gates is similar to that of XOR/XNOR
gates, and with an increase of fan-in the logical masking capability of
majority/minority gates also increases
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