2,043 research outputs found
Hysteretic behavior of angular dependence of exchange bias in FeNi/FeMn bilayers
For FeNi/FeMn bilayers, the angular dependence of exchange bias shows hysteresis between clockwise and counterclockwise rotations, as a new signature. The hysteresis decreases for thick antiferromagnet layers. Calculations have clearly shown that the orientation of antiferromagnet spins also exhibits hysteresis between clockwise and counterclockwise rotations. This furnishes an interpretation of the macroscopic behavior of the ferromagnetic layer in terms of the thermally driven evolution of the magnetic state of the antiferromagnet layer
Quantum Bayesian implementation
Bayesian implementation concerns decision making problems when agents have
incomplete information. This paper proposes that the traditional sufficient
conditions for Bayesian implementation shall be amended by virtue of a quantum
Bayesian mechanism. In addition, by using an algorithmic Bayesian mechanism,
this amendment holds in the macro world.Comment: 14 pages, 3 figure
Three Dimensional Chern-Simons Theory as a Theory of Knots and Links
Three dimensional SU(2) Chern-Simons theory has been studied as a topological
field theory to provide a field theoretic description of knots and links in
three dimensions. A systematic method has been developed to obtain the
link-invariants within this field theoretic framework. The monodromy properties
of the correlators of the associated Wess-Zumino SU(2) conformal field
theory on a two-dimensional sphere prove to be useful tools. The method is
simple enough to yield a whole variety of new knot invariants of which the
Jones polynomials are the simplest example.Comment: 45 pages (without figures
Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Application to Discrete Data
We investigate how the divergence-free property of magnetic fields can be
exploited to resolve the azimuthal ambiguity present in solar vector
magnetogram data, by using line-of-sight and horizontal heliographic derivative
information as approximated from discrete measurements. Using synthetic data we
test several methods that each make different assumptions about how the
divergence-free property can be used to resolve the ambiguity. We find that the
most robust algorithm involves the minimisation of the absolute value of the
divergence summed over the entire field of view. Away from disk centre this
method requires the sign and magnitude of the line-of-sight derivatives of all
three components of the magnetic field vector.Comment: Solar Physics, in press, 20 pages, 11 figure
Novel Correspondence-based Approach for Consistent Human Skeleton Extraction
This paper presents a novel base-points-driven shape correspondence (BSC) approach to extract skeletons of articulated objects from 3D mesh shapes. The skeleton extraction based on BSC approach is more accurate than the traditional direct skeleton extraction methods. Since 3D shapes provide more geometric information, BSC offers the consistent information between the source shape and the target shapes. In this paper, we first extract the skeleton from a template shape such as the source shape automatically. Then, the skeletons of the target shapes of different poses are generated based on the correspondence relationship with source shape. The accuracy of the proposed method is demonstrated by presenting a comprehensive performance evaluation on multiple benchmark datasets. The results of the proposed approach can be applied to various applications such as skeleton-driven animation, shape segmentation and human motion analysis
Effects of carbohydrate, branched-chain amino acids, and arginine in recovery period on the subsequent performance in wrestlers
Many athletes need to participate in multiple events in a single day. The efficient post-exercise glycogen recovery may be critical for the performance in subsequent exercise. This study examined whether post-exercise carbohydrate supplementation could restore the performance in the subsequent simulated wrestling match. The effect of branched-chain amino acids and arginine on glucose disposal and performance was also investigated. Nine well-trained male wrestlers participated in 3 trials in a random order. Each trial contained 3 matches with a 1-hr rest between match 1 and 2, and a 2-hr rest between match 2 and 3. Each match contained 3 exercise periods interspersed with 1-min rests. The subjects alternated 10-s all-out sprints and 20-s rests in each exercise period. At the end of match 2, 3 different supplementations were consumed: 1.2 g/kg glucose (CHO trial), 1 g/kg glucose + 0.1 g/kg Arg + 0.1 g/kg BCAA (CHO+AA trial), or water (placebo trial). The peak and average power in the 3 matches was similar in the 3 trials. After the supplementation, CHO and CHO+AA trial showed significantly higher glucose and insulin, and lower glycerol and non-esterified fatty acid concentrations than the placebo trial. There was no significant difference in these biochemical parameters between the CHO and CHO+AA trials. Supplementation of carbohydrate with or without BCAA and arginine during the post-match period had no effect on the performance in the following simulated match in wrestlers. In addition, BCAA and arginine did not provide additional insulinemic effect
Knot invariants from rational conformal field theories
A framework for studying knot and link invariants from any rational conformal
field theory is developed. In particular, minimal models, superconformal models
and models are studied. The invariants are related to the invariants
obtained from the Wess-Zumino models associated with the coset representations
of these models. Possible Chern-Simons representation of these models is also
indicated. This generalises the earlier work on knot and link invariants from
Chern-Simons theories.Comment: 18pages+6 figures (available on request through email
Magnetic Connectivity between Active Regions 10987, 10988, and 10989 by Means of Nonlinear Force-Free Field Extrapolation
Extrapolation codes for modelling the magnetic field in the corona in
cartesian geometry do not take the curvature of the Sun's surface into account
and can only be applied to relatively small areas, \textit{e.g.}, a single
active region. We apply a method for nonlinear force-free coronal magnetic
field modelling of photospheric vector magnetograms in spherical geometry which
allows us to study the connectivity between multi-active regions. We use vector
magnetograph data from the Synoptic Optical Long-term Investigations of the Sun
survey (SOLIS)/Vector Spectromagnetograph(VSM) to model the coronal magnetic
field, where we study three neighbouring magnetically connected active regions
(ARs: 10987, 10988, 10989) observed on 28, 29, and 30 March 2008, respectively.
We compare the magnetic field topologies and the magnetic energy densities and
study the connectivities between the active regions(ARs). We have studied the
time evolution of magnetic field over the period of three days and found no
major changes in topologies as there was no major eruption event. From this
study we have concluded that active regions are much more connected
magnetically than the electric current.Comment: Solar Physic
Unique Identification of Lee-Wick Gauge Bosons at Linear Colliders
Grinstein, O'Connell and Wise have recently presented an extension of the
Standard Model (SM), based on the ideas of Lee and Wick (LW), which
demonstrates an interesting way to remove the quadratically divergent
contributions to the Higgs mass induced by radiative corrections. This model
predicts the existence of negative-norm copies of the usual SM fields at the
TeV scale with ghost-like propagators and negative decay widths, but with
otherwise SM-like couplings. In earlier work, it was demonstrated that the LW
states in the gauge boson sector of these models, though easy to observe,
cannot be uniquely identified as such at the LHC. In this paper, we address the
issue of whether or not this problem can be resolved at an collider
with a suitable center of mass energy range. We find that measurements of the
cross section and the left-right polarization asymmetry associated with Bhabha
scattering can lead to a unique identification of the neutral electroweak gauge
bosons of the Lee-Wick type.Comment: 16 pages, 6 figures; discussion and references adde
Investigation of a two-phase flow natural circulation loop with divergent microchannel evaporator
Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The development of microelectronics is toward high
performance, high efficiency and yet small size. Thermal
management of microelectronics is of critical concern and
significant interest. Microchannel boiling is an advanced
cooling technology for high heat flux devices. The present
study explores heat removal capability of a two-phase natural
circulation loop with divergent microchannel evaporator. Our
previous studies revealed that a diverging cross section design
significantly could stabilize and enhance the heat transfer of
flow boiling. The temperatures at the inlet and outlet of both
evaporator and condensing units are measured to evaluate the
heat removal capability of the loop. Moreover, the pressure
changes through the downcomer and lower horizontal tube are
both measured to deduce the flow rate through the loop based
on the relationship between flow rate and pressure drop. This
study uses the high speed video camera to capture the flow
patterns in the evaporator and riser. The working fluid
employed in the present study is ethanol, as its boiling
temperature at atmospheric pressure is 78.4 ℃, which is below
the temperature limit of the most microelectronic materials. The
results show that the loop mass flow rate increases
monotonically with increasing the heating power of the
evaporator after boiling incipience. The current experimental
results indicate that the highest base heat flux could achieve is
about 105 kWm-2 with no sign of dry-out and it has great
potential to reach a higher heat flux. Moreover, it is found that
the loop instability appears at low heating powers after boiling
begins, while it can be suppressed if the input power is higher
than 20W. Indeed, the present two-phase natural circulation
loop with divergent microchannel evaporator demonstrates
stable circulation with high heat transfer capability.dc201
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