38,362 research outputs found
SU(4) Theory for Spin Systems with Orbital Degeneracy
The isotropic limit of spin systems with orbital degeneracy is shown to have
global SU(4) symmetry. On many 2D lattices, the ground state does not posses
long range order, which may explain the observed spin liquid properties of
. In the SU(4) Neel ordered state, spin-spin correlations can be
antiferromagneitc between two neighboring sites with parallel magnetic moments.Comment: 11 pages, 2 figures. submitted to PR
A novel approach for quality control system using sensor fusion of infrared and visual image processing for laser sealing of food containers
This paper presents a new mechatronic approach of using infrared thermography combined with image processing for the quality control of a laser sealing process for food containers. The suggested approach uses an on-line infrared system to assess the heat distribution within the container seal in order to guarantee the integrity of the process. Visual image processing is then used for quality assurance to guarantee optimum sealing. The results described in this paper show examples of the capability of the condition monitoring system to detect faults in the sealing process. The results found indicate that the suggested approach could form an effective quality control and assurance system
Mott Relation for Anomalous Hall and Nernst effects in Ga1-xMnxAs Ferromagnetic Semiconductors
The Mott relation between the electrical and thermoelectric transport
coefficients normally holds for phenomena involving scattering. However, the
anomalous Hall effect (AHE) in ferromagnets may arise from intrinsic spin-orbit
interaction. In this work, we have simultaneously measured AHE and the
anomalous Nernst effect (ANE) in Ga1-xMnxAs ferromagnetic semiconductor films,
and observed an exceptionally large ANE at zero magnetic field. We further show
that AHE and ANE share a common origin and demonstrate the validity of the Mott
relation for the anomalous transport phenomena
Temperature dependence of the conductivity of the electronic crystal
We study the temperature dependence of the conductivity of the 2D electronic
solid. In realistic samples, a domain structure forms in the solid and each
domain randomly orients in the absence of the in-plane field. At higher
temperature, the electron transport is governed by thermal activation form of
. The impurities will localize the
electron states along the edges of the crystal domains. At sufficient low
temperature, another transport mechanism called Mott's variable range hopping
mechanism, similar to that in a disorder insulator takes effect. We show that
as the temperature decreases, a crossover from the fixed range hopping of the
transport to the variable range hopping of transport in the 2D electron system
may be experimentally observed.Comment: 4 pages,1 figure
Self-consistent tilted-axis-cranking study of triaxial strongly deformed bands in Er at ultrahigh spin
Stimulated by recent experimental discoveries, triaxial strongly deformed
(TSD) states in Er at ultrahigh spins have been studied by means of the
Skyrme-Hartree-Fock model and the tilted-axis-cranking method. Restricting the
rotational axis to one of the principal axes -- as done in previous cranking
calculations -- two well-defined TSD minima in the total Routhian surface are
found for a given configuration: one with positive and another with negative
triaxial deformation . By allowing the rotational axis to change
direction, the higher-energy minimum is shown to be a saddle point. This
resolves the long-standing question of the physical interpretation of the two
triaxial minima at a very similar quadrupole shape obtained in the principal
axis cranking approach. Several TSD configurations have been predicted,
including a highly deformed band expected to cross lesser elongated TSD bands
at the highest spins. Its transitional quadrupole moment \,eb
is close to the measured value of 11\,eb; hence, it is a candidate for
the structure observed in experiment.Comment: 5 pages, 5 figure
Towards bioinspired superhydrophobic poly(L-lactic acid) surfaces using phase inversion-based methods
The water repellency and self-cleaning ability of many biological surfaces has inspired many
fundamental and practical studies related to the development of synthetic superhydrophobic
surfaces. However, the investigation of such substrates made of biodegradable polymers has
been scarce. Simple approaches based on a single step, performed at room temperature (and
pressure), were implemented to obtain superhydrophobic poly(L-lactic acid) (PLLA) surfaces
via phase inversion-based methods, without addition of low-surface-energy compounds. Water
contact angles above 150⊠were obtained using some processing conditions. In such cases
scanning electronic microscopy micrographs of such surfaces revealed a clear rough texture
composed by leafy clusters with micro-nano binary structures. Such materials could be used in
specific environmental and biomedical applications, namely in implantable materials or in
antibacterial or antithrombogenic surfaces
Frequency-domain transient analysis of multitime partial differential equation systems
Multitime partial differential equations (MPDEs) provide an efficient method to simulate circuits with widely separated rates of inputs. This paper proposes a fast and accurate frequency-domain multitime transient analysis method for MPDE systems, which fills in the gap for the lack of general frequency-domain solver for MPDE systems. A block-pulse function-based multidimensional inverse Laplace transform strategy is adopted. The method can be applied to discrete input systems. Numerical examples then confirm its superior accuracy, under similar efficiency, over time-domain solvers. © 2011 IEEE.published_or_final_versionThe 2011 IEEE/IFIP 19th International Conference on VLSI and System-on-Chip (VLSI-SoC), Hong Kong, 3-5 October 2011. In IFIP International Conference on Very Large Scale Integration Proceedings, 2011, p. 160-16
Drug release of pH/temperature-responsive calcium alginate/poly(N-isopropylacrylamide) semi IPN beads
A series of semi-interpenetrating, polymer
network (semi-IPN), hydrogel beads, composed of calcium
alginate (Ca-alginate) and poly(N-isopropylacrylamide)
(PNIPAAM), were prepared for a pH/temperature-sensitive
drug delivery study. The equilibrium swelling showed the
independent pH- and thermo- responsive nature of the
developed materials. At pHŒ2.1, the release amount of
indomethacin incorporated into these beads was about 10%
within 400 min, while this value approached to 95% at
pHŒ7.4. The release rate of the drug was higher at 37 8Cthan
that at 25 8C and increased slightly with increasing
PNIPAAM content. These results suggest that the Caalginate/
PNIPAAM beads have the potential to be used as
an effective pH/temperature sustainable delivery system of
bioactive agents
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