1,368 research outputs found
Frangible tube energy dissipation Patent
Energy dissipating shock absorbing system for land payload recovery or vehicle brakin
Break-up of metal tube makes one-time shock absorber, bars rebound
A frangible metal tube has the capability to dissipate the energy generated when a vehicle lands with excessive velocity. The tube is so placed that, at impact, it is forced against a die and, as it fragments, energy is absorbed
Graphene spin capacitor for magnetic field sensing
An analysis of a novel magnetic field sensor based on a graphene spin
capacitor is presented. The proposed device consists of graphene nanoribbons on
top of an insulator material connected to a ferromagnetic source/drain. The
time evolution of spin polarized electrons injected into the capacitor can be
used for an accurate determination at room temperature of external magnetic
fields. Assuming a spin relaxation time of 100 ns, magnetic fields on the order
of mOe may be detected at room temperature. The observational
accuracy of this device depends on the density of magnetic defects and spin
relaxation time that can be achieved.Comment: 6 pages, 3 figure
Weak ferromagnetism of antiferromagnetic domains in graphene with defects
Magnetic properties of graphene with randomly distributed magnetic
defects/vacancies are studied in terms of the Kondo Hamiltonian in the mean
field approximation. It has been shown that graphene with defects undergoes a
magnetic phase transition from a paramagnetic to a antiferromagnetic (AFM)
phase once the temperature reaches the critical point . The defect
straggling is taken into account as an assignable cause of multiple nucleation
into AFM domains. Since each domain is characterized by partial compensating
magnetization of the defects associated with different sublattices, together
they reveal a super-paramagnetic behavior in a magnetic field. Theory
qualitatively describe the experimental data provided the temperature
dependence of the AFM domain structure.Comment: 8 pages, 2 figure
Surface Polar Phonon Dominated Electron Transport in Graphene
The effects of surface polar phonons on electronic transport properties of
monolayer graphene are studied by using a Monte Carlo simulation. Specifically,
the low-field electron mobility and saturation velocity are examined for
different substrates (SiC, SiO2, and HfO2) in comparison to the intrinsic case.
While the results show that the low-field mobility can be substantially reduced
by the introduction of surface polar phonon scattering, corresponding
degradation of the saturation velocity is not observed for all three substrates
at room temperature. It is also found that surface polar phonons can influence
graphene electrical resistivity even at low temperature, leading potentially to
inaccurate estimation of the acoustic phonon deformation potential constant
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