3,758 research outputs found
Width and Magnetic Field Dependence of Transition Temperature in Ultranarrow Superconducting Wires
We calculate the transition temperature in ultranarrow superconducting wires
as a function of wire width, resistance and applied magnetic field. We compare
the results of first-order perturbation theory and the non-perturbative
resummation technique developed by Oreg and Finkel'stein. The latter technique
is found to be superior as it is valid even in the strong disorder limit. In
both cases the predicted additional suppression of the transition temperature
due to the reduced dimensionality is strongly dependent upon the boundary
conditions used. When we use the correct (zero-gradient) boundary conditions,
we find that theory and experiment are consistent, although more experimental
data is required to verify this systematically. We calculate the magnetic field
dependence of the transition temperature for different wire widths and
resistances in the hope that this will be measured in future experiments. The
predicted results have a rich structure - in particular we find a dimensional
crossover which can be tuned by varying either the width of the wire or its
resistance per square.Comment: 12 pages, 1 table, 7 figures. The changes made to the paper are ones
of emphasis. The comparison between theory and experiment has been altered,
and detailed comparisons of various approximations have been omitted,
although the results are summarised in the paper. Much more emphasis has been
placed on the new predictions of the effect of an applied magnetic field on
transition temperature in wires (Figs. 5-7
On the importance of background subtraction in the analysis of coronal loops observed with TRACE
In the framework of TRACE coronal observations, we compare the analysis and
diagnostics of a loop after subtracting the background with two different and
independent methods. The dataset includes sequences of images in the 171 A, 195
A filter bands of TRACE. One background subtraction method consists in taking
as background values those obtained from interpolation between concentric
strips around the analyzed loop. The other method is a pixel-to-pixel
subtraction of the final image when the loop had completely faded out, already
used by Reale & Ciaravella 2006. We compare the emission distributions along
the loop obtained with the two methods and find that they are considerably
different. We find differences as well in the related derive filter ratio and
temperature profiles. In particular, the pixel-to-pixel subtraction leads to
coherent diagnostics of a cooling loop. With the other subtraction the
diagnostics are much less clear. The background subtraction is a delicate issue
in the analysis of a loop. The pixel-to-pixel subtraction appears to be more
reliable, but its application is not always possible. Subtraction from
interpolation between surrounding regions can produce higher systematic errors,
because of intersecting structures and of the large amount of subtracted
emission in TRACE observations.Comment: 9 pages, 9 figure
Pengaruh Atmosfer Toko dan Kesesuaian Harga terhadap Keputusan Pembelian Konsumen pada Temday Store Denpasar
Purchase decisions is the process by which consumers make an assessment of the various alternative options and choose one or more alternatives are needed based on certain considerations. Study aimed to examine the effect of stores atmospheric and prices suitability on consumer purchase decisions at Temday Store Denpasar. Samples are taken by 90 respondents, using purposive sampling method. Data collection is done by distributing questionnaires. Analysis technique was multiple linear regression analysis. Based on the results of the analysis showed that the store atmosphere has positive and significant effect on purchase decisions. Price suitability positive and significant impact on purchase decisions. To improve purchase decisions at Temday Store Denpasar, Temday Store needs to add a payment facility that make consumers easier on payment transactions and maintain the cleanliness the room so that consumers feel comfortable and offers affordable prices of products to encourage consumers make purchase decisions
Generating Bounds for the Ground State Energy of the Infinite Quantum Lens Potential
Moment based methods have produced efficient multiscale quantization
algorithms for solving singular perturbation/strong coupling problems. One of
these, the Eigenvalue Moment Method (EMM), developed by Handy et al (Phys. Rev.
Lett.{\bf 55}, 931 (1985); ibid, {\bf 60}, 253 (1988b)), generates converging
lower and upper bounds to a specific discrete state energy, once the signature
property of the associated wavefunction is known. This method is particularly
effective for multidimensional, bosonic ground state problems, since the
corresponding wavefunction must be of uniform signature, and can be taken to be
positive. Despite this, the vast majority of problems studied have been on
unbounded domains. The important problem of an electron in an infinite quantum
lens potential defines a challenging extension of EMM to systems defined on a
compact domain. We investigate this here, and introduce novel modifications to
the conventional EMM formalism that facilitate its adaptability to the required
boundary conditions.Comment: Submitted to J. Phys.
Benchmark full configuration-interaction calculations on HF and NH2
Full configuration-interaction (FCI) calculations are performed at selected geometries for the 1-sigma(+) state of HF and the 2-B(1) and 2-A(1) states of NH2 using both DZ and DZP gaussian basis sets. Higher excitations become more important when the bonds are stretched and the self-consistent field (SCF) reference becomes a poorer zeroth-order description of the wave function. The complete active space SCF - multireference configuration-interaction (CASSCF-MRCI) procedure gives excellent agreement with the FCI potentials, especially when corrected with a multi-reference analog of the Davidson correction
Distributed leadership, trust and online communities
This paper analyses the role of distributed leadership and trust in online communities. The team-based informal ethos of online collaboration requires a different kind of leadership from that in formal positional hierarchies. Such leadership may be more flexible and sophisticated, capable of encompassing ambiguity and rapid change. Online leaders need to be partially invisible, delegating power and distributing tasks. Yet, simultaneously, online communities are facilitated by the high visibility and subtle control of expert leaders. This paradox: that leaders need to be both highly visible and invisible as appropriate, was derived from prior research and tested in the analysis of online community discussions using a pattern-matching process. It is argued that both leader visibility and invisibility are important for the facilitation of trusting collaboration via distributed leadership. Advanced leadership responses to complex situations in online communities foster positive group interaction and decision-making, facilitated through active distribution of specific tasks
Development of a Computerized App Based on Fitness Norms of University Students
Please view abstract in the attached PDF fil
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