11,101 research outputs found
The load type influence on the filtration behavior of soil-nonwoven geotextile composite
100學年度研究獎補助論文[[abstract]]The load type influence on the filtration behavior of soil-nonwoven geotextile composite has been studied through a series of tests using an experimental apparatus designed specifically for the laboratory tests. In these tests, the soil-geotextile composite was formed by inserting a piece of nonwoven geotextile between a 5-cm thick soil and a layer of steel beads. One of the three load types, namely sustained load, pulsatory load, and compound load of pulsatory and sustained load, was applied to the composite prior to the filtration test. Water was allowed to flow through the composite from the soil into a drainage layer at various hydraulic gradients. The permeability value was extracted by using Darcy's law to characterize the filtration performance of the entire soil-geotextile composite.[[notice]]補正完畢[[incitationindex]]EI[[booktype]]紙
Supersymmetric Solutions in Four-Dimensional Off-Shell Curvature-Squared Supergravity
Off-shell formulations of supergravities allow one to add closed-form
higher-derivative super-invariants that are separately supersymmetric to the
usual lower-derivative actions. In this paper we study four-dimensional
off-shell N=1 supergravity where additional super-invariants associated with
the square of the Weyl tensor and the square of the Ricci scalar are included.
We obtain a variety of solutions where the metric describes domain walls,
Lifshitz geometries, and also solutions of a kind known as gyratons. We find
that in some cases the solutions can be supersymmetric for appropriate choices
of the parameters. In some solutions the auxiliary fields may be imaginary. One
may reinterpret these as real solutions in an analytically-continued theory.
Since the supersymmetry transformation rules now require the gravitino to be
complex, the analytically-continued theory has a "fake supersymmetry" rather
than a genuine supersymmetry. Nevertheless, the concept of
pseudo-supersymmetric solutions is a useful one, since the Killing spinor
equations provide first-order equations for the bosonic fields.Comment: 28 page
DC Conductivities from Non-Relativistic Scaling Geometries with Momentum Dissipation
We consider a gravitational theory with two Maxwell fields, a dilatonic
scalar and spatially dependent axions. Black brane solutions to this theory are
Lifshitz-like and violate hyperscaling. Working with electrically charged
solutions, we calculate analytically the holographic DC conductivities when
both gauge fields are allowed to fluctuate. We discuss some of the subtleties
associated with relating the horizon to the boundary data, focusing on the role
of Lifshitz asymptotics and the presence of multiple gauge fields. The axionic
scalars lead to momentum dissipation in the dual holographic theory. Finally,
we examine the behavior of the DC conductivities as a function of temperature,
and comment on the cases in which one can obtain a linear resistivity.Comment: 32 pages, 3 figures. Figures and references added. Discussion
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Improvement of the Determination of the WIMP Mass from Direct Dark Matter Detection Data
Weakly Interacting Massive Particles (WIMPs) are one of the leading
candidates for Dark Matter. We developed a model-independent method for
determining the WIMP mass by using data (i.e., measured recoil energies) of
direct detection experiments. Our method is independent of the as yet unknown
WIMP density near the Earth, of the form of the WIMP velocity distribution, as
well as of the WIMP-nucleus cross section. It requires however positive signals
from at least two detectors with different target nuclei. At the first phase of
this work we found a systematic deviation of the reconstructed WIMP mass from
the real one for heavy WIMPs. Now we improved this method so that this
deviation can be strongly reduced for even very high WIMP mass. The statistical
error of the reconstructed mass has also been reduced. In a background-free
evironment, a WIMP mass of ~ 50 GeV could in principle be determined with an
error of ~ 35% with only 2 times 50 events.Comment: 3 pages, 2 figures, to appear in the SUSY08 proceeding
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