12,385 research outputs found
Laser induced magnetization switching in films with perpendicular anisotropy: a comparison between measurements and a multi-macrospin model
Thermally-assisted ultra-fast magnetization reversal in a DC magnetic field
for magnetic multilayer thin films with perpendicular anisotropy has been
investigated in the time domain using femtosecond laser heating. The experiment
is set-up as an optically pumped stroboscopic Time Resolved Magneto-Optical
Kerr Effect magnetometer. It is observed that a modest laser fluence of about
0.3 mJ/square-cm induces switching of the magnetization in an applied field
much less than the DC coercivity (0.8 T) on the sub-nanosecond time-scale. This
switching was thermally-assisted by the energy from the femtosecond pump-pulse.
The experimental results are compared with a model based on the Landau
Lifschitz Bloch equation. The comparison supports a description of the reversal
process as an ultra-fast demagnetization and partial recovery followed by
slower thermally activated switching due to the spin system remaining at an
elevated temperature after the heating pulse.Comment: 8 pages, 10 figures, to be submitted to PR
Possible approach to improve sensitivity of a Michelson interferometer
We propose a possible approach to achieve an 1/N sensitivity of Michelson
interferometer by using a properly designed random phase modulation. Different
from other approaches, the sensitivity improvement does not depend on
increasing optical powers or utilizing the quantum properties of light.
Moreover the requirements for optical losses and the quantum efficiencies of
photodetection systems might be lower than the quantum approaches and the
sensitivity improvement is frequency independent in all detection band.Comment: 8 pages, 3 figures, new versio
DNA Vaccines Encoding Antigen Targeted to MHC Class II Induce Influenza-Specific CD8+ T Cell Responses, Enabling Faster Resolution of Influenza Disease
Current influenza vaccines are effective but imperfect, failing to cover against emerging strains of virus and requiring seasonal administration to protect against new strains. A key step to improving influenza vaccines is to improve our understanding of vaccine induced protection. Whilst it is clear that antibodies play a protective role, vaccine induced CD8+ T cells can improve protection. To further explore the role of CD8+ T cells we used a DNA vaccine that encodes antigen dimerised to an immune cell targeting module. Immunising CB6F1 mice with the DNA vaccine in a heterologous prime boost regime with the seasonal protein vaccine improved the resolution of influenza disease compared to protein alone. This improved disease resolution was dependent on CD8+ T cells. However, DNA vaccine regimes that induced CD8+ T cells alone were not protective and did not boost the protection provided by protein. The MHC targeting module used was an anti-I-Ed single chain antibody specific to the BALB/c strain of mice. To test the role of MHC targeting we compared the response between BALB/c, C57BL/6 mice and an F1 cross of the two strains (CB6F1). BALB/c mice were protected, C57BL/6 were not and the F1 had an intermediate phenotype; showing that the targeting of antigen is important in the response. Based on these findings, and in agreement with other studies using different vaccines, we conclude that in addition to antibody, inducing a protective CD8 response is important in future influenza vaccines
Synthesis and characterization of photoaffinity labelling reagents towards the Hsp90 C-terminal domain
Glucosyl-novobiocin-based diazirine photoaffinity labelling reagents (PALs) were designed and synthesized to probe the Hsp90 C-terminal domain unknown binding pocket and the structure-activity relationship. Five PALs were successfully synthesized from novobiocin in six consecutive steps employing phase transfer catalytic glycosylation. Reactions were monitored and guided by analytical LC/MS which led to different strategies of adding either a PAL precursor or a sugar moiety first. The structures and bonding linkages of these compounds were characterised by various 2D-NMR spectroscopy and MS techniques. Synthetic techniques provide powerful probes for unknown protein binding pockets
Entanglement scaling in two-dimensional gapless systems
We numerically determine subleading scaling terms in the ground-state
entanglement entropy of several two-dimensional (2D) gapless systems, including
a Heisenberg model with N\'eel order, a free Dirac fermion in the {\pi}-flux
phase, and the nearest-neighbor resonating-valence-bond wavefunction. For these
models, we show that the entanglement entropy between cylindrical regions of
length x and L - x, extending around a torus of length L, depends upon the
dimensionless ratio x/L. This can be well-approximated on finite-size lattices
by a function ln(sin({\pi}x/L)), akin to the familiar chord-length dependence
in one dimension. We provide evidence, however, that the precise form of this
bulk-dependent contribution is a more general function in the 2D thermodynamic
limit.Comment: 5 pages, 5 figure
Isoscalar Hamiltonians for light atomic nuclei
The charge-dependent realistic nuclear Hamiltonian for a nucleus, composed of
neutrons and protons, can be successfully approximated by a charge-independent
one. The parameters of such a Hamiltonian, i.e., the nucleon mass and the NN
potential, depend upon the mass number A, charge Z and isospin quantum number T
of state of the studied nucleus.Comment: REVTeX, 22 pages, 3 eps figures, to appear in PR
Impact of technological blockchain paradigm on the movement of intellectual property in the digital space
The article is dedicated to investigate the problem of influence of cutting edge digital technology on the virtual and real legal relations, related to the movement and the turnover of intellectual property.
Using the method of analyzing modern definitions of blockchain, and relying on the political-economic theory of social redistribution of wealth, authors define the term blockchain and its principles as a technological paradigm.
Authors conclude the fact that blockchain can be used to guarantee intellectual property rights and it should be accepted at the national level.
As a mechanism of a trusted environment, blockchain allows to reduce transaction costs and increase the level of commercialization of intellectual property.peer-reviewe
Feedback control of thermal lensing in a high optical power cavity
This paper reports automatic compensation of strong thermal lensing in a suspended 80 m optical cavity with sapphire test mass mirrors. Variation of the transmitted beam spot size is used to obtain an error signal to control the heating power applied to the cylindrical surface of an intracavity compensation plate. The negative thermal lens created in the compensation plate compensates the positive thermal lens in the sapphire test mass, which was caused by the absorption of the high intracavity optical power. The results show that feedback control is feasible to compensate the strong thermal lensing expected to occur in advanced laser interferometric gravitational wave detectors. Compensation allows the cavity resonance to be maintained at the fundamental mode, but the long thermal time constant for thermal lensing control in fused silica could cause difficulties with the control of parametric instabilities.This research was supported by the Australian
Research Council and the Department of Education,
Science and Training and by the U.S. National Science Foundation,
through LIGO participation in the HOPF
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