645 research outputs found
Superfluid properties of one-component Fermi gas with an anisotropic p-wave interaction
We investigate superfluid properties and strong-coupling effects in a
one-component Fermi gas with an anisotropic p-wave interaction. Within the
framework of the Gaussian fluctuation theory, we determine the superfluid
transition temperature , as well as the temperature at which
the phase transition from the -wave pairing state to the -wave
state occurs below . We also show that while the anisotropy of the
p-wave interaction enhances in the strong-coupling regime, it
suppresses .Comment: 7 pages, 3 figures, proceedings of QFS 201
Dynamics of Inner Galactic Disks: The Striking Case of M100
We investigate gas dynamics in the presence of a double inner Lindblad
resonance within a barred disk galaxy. Using an example of a prominent spiral,
M100, we reproduce the basic central morphology, including four dominant
regions of star formation corresponding to the compression maxima in the gas.
These active star forming sites delineate an inner boundary (so-called nuclear
ring) of a rather broad oval detected in the near infrared. We find that
inclusion of self-gravitational effects in the gas is necessary in order to
understand its behavior in the vicinity of the resonances and its subsequent
evolution. The self-gravity of the gas is also crucial to estimate the effect
of a massive nuclear ring on periodic orbits in the stellar bar.Comment: 11 pages, postscript, compressed, uuencoded. Paper and 4 figures
available at ftp://pa.uky.edu/shlosman/nobel or at
http://www.pa.uky.edu/~shlosman/ . Invited talk at the Centennial Nobel
Symposium on "Barred Galaxies and Circumnuclear Activity," A.Sandquist et al.
(Eds.), Springer-Verlag, in pres
Nano Fe3O4-activated carbon composites for aqueous supercapacitors
In this study, a symmetric supercapacitor has been fabricated by adopting the nanostructured iron oxide (Fe3O4)-activated carbon (AC) composite as the core electrode materials. The composite electrodes were prepared via a facile mechanical mixing process and PTFE polymeric solution has been used as the electrode material binder. Structural analysis of the nanocomposite electrodes were characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The electrochemical performances of the prepared supercapacitor were studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 1.0 M Na2SO3 and 1.0 M Na2SO4 aqueous solutions, respectively. The experimental results showed that the highest specific capacitance of 43 F/g is achieved with a fairly low Fe3O4 nanomaterials loading (4 wt. %) in 1 M Na2SO3. It is clear that the low concentration of nanostructured Fe3O4 has improved the capacitive performance of the composite via pseudocapacitance charge storage mechanism as well as the enhancement on the specific surface areas of the electrode. However, further increasing of the Fe3O4 content in the electrode is found to distort the capacitive performance and deteriorate the specific surface area of the electrode, mainly due to the aggregation of the Fe3O4 particles within the composite. Additionally, the CV results showed that the Fe3O4/AC nanocomposite electrode in Na2SO3 electrolyte exhibits a better charge storage performance if compared with Na2SO4 solution. It is believed that Fe3O4 nanoparticles can provide favourable surface adsorption sites for sulphite (SO32-) anions which act as catalysts for subsequent redox and intercalation reactions
Patterns of Interactions in Complex Social Networks Based on Coloured Motifs Analysis
Coloured network motifs are small subgraphs that enable to discover and interpret the patterns of interaction within the complex networks. The analysis of three-nodes motifs where the colour of the node reflects its high – white node or low – black node centrality in the social network is presented in the paper. The importance of the vertices is assessed by utilizing two measures: degree prestige and degree centrality. The distribution of motifs in these two cases is compared to mine the interconnection patterns between nodes. The analysis is performed on the social network derived from email communication
A magnetization equation for non-equilibrium spin systems
A magnetization equation for a system of spins evolving non-adiabatically and
out of equilibrium is derived without specifying the internal interactions. For
relaxation processes, this equation provides a general form of magnetization
damping. A special case of the spin-spin exchange interaction is considered.Comment: 9 pages, LATEX file; talk given at Theory Canada III, June 13-16,
2007, University of Alberta, Edmonton; to appear in Canadian Journal of
Physic
An ancient role for Gata-1/2/3 and Scl transcription factor homologs in the development of immunocytes
AbstractAlthough vertebrate hematopoiesis is the focus of intense study, immunocyte development is well-characterized in only a few invertebrate groups. The sea urchin embryo provides a morphologically simple model for immune cell development in an organism that is phylogenetically allied to vertebrates. Larval immunocytes, including pigment cells and several blastocoelar cell subtypes, emerge from a population of non-skeletal mesodermal (NSM) precursors that is specified at the blastula stage. This ring of cells is first partitioned into oral and aboral fields with distinct blastocoelar and pigment cell gene regulatory programs. The oral field is subsequently specified into several distinct immune and non-immune cell types during gastrulation. Here we characterize the oral NSM expression and downstream function of two homologs of key vertebrate hematopoietic transcription factors: SpGatac, an ortholog of vertebrate Gata-1/2/3 and SpScl, an ortholog of Scl/Tal-2/Lyl-1. Perturbation of SpGatac affects blastocoelar cell migration at gastrulation and later expression of immune effector genes, whereas interference with SpScl function disrupts segregation of pigment and blastocoelar cell precursors. Homologs of several transcription regulators that interact with Gata-1/2/3 and Scl factors in vertebrate hematopoiesis are also co-expressed in the oral NSM, including SpE-protein, the sea urchin homolog of vertebrate E2A/HEB/E2-2 and SpLmo2, an ortholog of a dedicated cofactor of the Scl–GATA transcription complex. Regulatory analysis of SpGatac indicates that oral NSM identity is directly suppressed in presumptive pigment cells by the transcription factor SpGcm. These findings provide part of a comparative basis to understand the evolutionary origins and regulatory biology of deuterostome immune cell differentiation in the context of a tractable gene regulatory network model
Design and Development of an RFID-based HIS - A Case Study
The Healthcare industry involves critical activities where small mistakes could cause huge loss of life and incur massive financial losses. Improving operational efficiency and enhancing data correctness of patients are the prime targets of using hospital information system (HIS). Radio Frequency Identification (RFID) technology, with a unique ability to perform automatic data collection without any human intervention, has gained great interest in the healthcare industry. In this research, an RFID‐enabled HIS is proposed for improving operations in a hospital. This research presents the fundamentals of RFID, the benefits and its challenges, and also demonstrates three improved signature applications. It aims at providing the healthcare industry with a comprehensive understanding of RFID and its suitability for healthcare applications. The proposed system is considered to be suitably operational, practical, and affordable for healthcare organizations not only in China and Hong Kong, but also in other countries
A Real Time Quality Monitoring System for the Lighting Industry: A Practical and Rapid Approach Using Computer Vision and Image Processing (CVIP) Tools
In China, the manufacturing of lighting
products is very labour intensive. The approach used to
check quality and control production relies on operators
who test using various types of fixtures. In order to
increase the competitiveness of the manufacturer and the
efficiency of production, the authors propose an
integrated system. This system has two major elements: a
computer vision system (CVS) and a real‐time
monitoring system (RTMS). This model focuses not only
on the rapid and practical application of modern
technology to a traditional industry, but also represents a
process innovation in the lighting industry. This paper
describes the design and development of the prototyped
lighting inspection system based on a practical and fast
approach using computer vision and imaging processing
(CVIP) tools. LabVIEW with IMAQ Vision Builder is the
chosen tool for building the CVS. Experimental results
show that this system produces a lower error rate than
humans produce in the quality checking process. The
whole integrated manufacturing strategy, aimed at
achieving a better performance, is most suitable for a
China and other labour intensive environments such as
India.
Spectrum of the Vortex Bound States of the Dirac and Schrodinger Hamiltonian in the presence of Superconducting Gaps
We investigate the vortex bound states both Schrodinger and Dirac Hamiltonian
with the s-wave superconducting pairing gap by solving the mean-field
Bogoliubov-de-Gennes equations. The exact vortex bound states spectrum is
numerically determined by the integration method, and also accompanied by the
quasi-classical analysis. It is found that the bound state energies is
proportional to the vortex angular momentum when the chemical potential is
large enough. By applying the external magnetic field, the vortex bound state
energies of the Dirac Hamiltonian are almost unchanged; whereas the energy
shift of the Schrodinger Hamiltonian is proportional to the magnetic field.
These qualitative differences may serve as an indirect evidence of the
existence of Majorana fermions in which the zero mode exists in the case of the
Dirac Hamiltonian only.Comment: 8 pages, 9 figure
Thermodynamic processes on a semiconductor surface during in-situ multi-beam laser interference patterning
Laser interference has been widely used to produce one-dimensional gratings and more recently has shown great potential for two-dimensional patterning. In this study, the authors examine by simulation, its application to in-situ patterning during materials growth. To understand the potential, it is important to study the surface processes resulting from the laser-matter interaction which have a key influence on the resulting growth mechanisms. In this work, the intensity distribution and the laser-semiconductor interaction resulting from four-beam interference patterns are analysed by numerical simulations. In particular, the authors derive the time and spatially dependent thermal distribution along with the thermal-induced desorption and surface diffusion. The results provide a crucial understanding of the light-induced thermal profile and show that the surface temperature and the surface adatom kinetics can be controlled by multi-beam pulsed laser interference patterning due to photothermal reactions. The approach has potential as an in-situ technique for the fast and precise nanostructuring of semiconductor material surfaces
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