11,725 research outputs found
Optical phase conjugation with less than a photon per degree of freedom
We demonstrate experimentally that optical phase conjugation can be used to
focus light through strongly scattering media even when far less than a photon
per optical degree of freedom is detected. We found that the best achievable
intensity contrast is equal to the total number of detected photons, as long as
the resolution of the system is high enough. Our results demonstrate that phase
conjugation can be used even when the photon budget is extremely low, such as
in high-speed focusing through dynamic media, or imaging deep inside tissue
Computational fluid dynamic analysis of underwater rubble mound leveling equipment against tidal current loading
Underwater rubble mound leveling works usually have been carried out as a preliminary process prior to\ud
the installation of caissons and blocks onto the seabed in a harbor and wave energy structures. So far, underwater\ud
construction works are mostly depended on divers. These divers are confronted with many difficulties, such as working\ud
time limitation due to depth, poor visibility in a working field and so on. These problems can be overcome using\ud
machineries in the underwater construction. The practical unmanned underwater equipment for port constructions was\ud
newly developed. The equipment can be applicable in underwater leveling works of rubble mound by using its blade\ud
and bucket with automatic arms. Also, it can monitor the working environment using sonars and optical devices. The\ud
safety analysis considering harsh circumstances such as strong currents is necessary because the equipment is usually\ud
mobilized on the seabed. In this paper, the effect of tidal current forces on the behavior of the equipment was\ud
investigated by using the Computational Fluid Dynamics (CFD), which is mainly used in investigating the relative\ud
movements of fluid and structure. The numerical results reveal that the possibility of overturning and sliding of the\ud
equipment can be negligible and the structural stability can be assured under a given current velocity of 1m/s
Magnetic Domain Patterns Depending on the Sweeping Rate of Magnetic Fields
The domain patterns in a thin ferromagnetic film are investigated in both
experiments and numerical simulations. Magnetic domain patterns under a zero
field are usually observed after an external magnetic field is removed. It is
demonstrated that the characteristics of the domain patterns depend on the
decreasing rate of the external field, although it can also depend on other
factors. Our numerical simulations and experiments show the following
properties of domain patterns: a sea-island structure appears when the field
decreases rapidly from the saturating field to the zero field, while a
labyrinth structure is observed for a slowly decreasing field. The mechanism of
the dependence on the field sweeping rate is discussed in terms of the concepts
of crystallization.Comment: 4 pages, 3 figure
Superconducting energy gap in MgCNi3 single crystals: Point-contact spectroscopy and specific-heat measurements
Specific heat has been measured down to 600 mK and up to 8 Tesla by the
highly sensitive AC microcalorimetry on the MgCNi3 single crystals with Tc ~ 7
K. Exponential decay of the electronic specific heat at low temperatures proved
that a superconducting energy gap is fully open on the whole Fermi surface, in
agreement with our previous magnetic penetration depth measurements on the same
crystals. The specific-heat data analysis shows consistently the strong
coupling strength 2D/kTc ~ 4. This scenario is supported by the direct gap
measurements via the point-contact spectroscopy. Moreover, the spectroscopy
measurements show a decrease in the critical temperature at the sample surface
accounting for the observed differences of the superfluid density deduced from
the measurements by different techniques
Production and optical properties of liquid scintillator for the JSNS experiment
The JSNS (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron
Source) experiment will search for neutrino oscillations over a 24 m short
baseline at J-PARC. The JSNS inner detector will be filled with 17 tons
of gadolinium-loaded liquid scintillator (LS) with an additional 31 tons of
unloaded LS in the intermediate -catcher and outer veto volumes.
JSNS has chosen Linear Alkyl Benzene (LAB) as an organic solvent because
of its chemical properties. The unloaded LS was produced at a refurbished
facility, originally used for scintillator production by the RENO experiment.
JSNS plans to use ISO tanks for the storage and transportation of the LS.
In this paper, we describe the LS production, and present measurements of its
optical properties and long term stability. Our measurements show that storing
the LS in ISO tanks does not result in degradation of its optical properties.Comment: 7 pages, 4 figures
Culex tarsalis is a competent vector species for Cache Valley virus
Background: Cache Valley virus (CVV) is a mosquito-borne orthobunyavirus endemic in North America. The virus is
an important agricultural pathogen leading to abortion and embryonic lethality in ruminant species, especially
sheep. The importance of CVV in human public health has recently increased because of the report of severe
neurotropic diseases. However, mosquito species responsible for transmission of the virus to humans remain to be
determined. In this study, vector competence of three Culex species mosquitoes of public health importance, Culex
pipiens, Cx. tarsalis and Cx. quinquefasciatus, was determined in order to identify potential bridge vector species
responsible for the transmission of CVV from viremic vertebrate hosts to humans.
Results: Variation of susceptibility to CVV was observed among selected Culex species mosquitoes tested in this
study. Per os infection resulted in the establishment of infection and dissemination in Culex tarsalis, whereas Cx.
pipiens and Cx. quinquefasciatus were highly refractory to CVV. Detection of viral RNA in saliva collected from
infected Cx. tarsalis provided evidence supporting its role as a competent vector.
Conclusions: Our study provided further understanding of the transmission cycles of CVV and identifies Cx. tarsalis
as a competent vector
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Glide paths for a retirement plan with deferred annuities
We construct investment glide paths for a retirement plan using both traditional asset classes and deferred annuities. The glide paths are approximated by averaging the asset proportions of stochastic optimal investment solutions. The objective function consists of power utility in terms of secured retirement income from purchased deferred annuities, as well as a bequest that can be withdrawn before retirement. Compared with conventional glide paths and investment strategies, our deferred annuity-enhanced glide paths provide the investor with higher welfare gains, more efficient investment portfolios, and more responsive retirement income patterns and bequest levels to different fee structures and personal preferences
Discrete Ambiguities in the Measurement of the Weak Phase Gamma
Several time-independent methods have been devised for measuring the phase
gamma of the Cabibbo-Kobayashi-Maskawa unitarity triangle. It is shown that
such measurements generally suffer from discrete ambiguity which is at least
8-fold, not 4-fold as commonly stated. This has serious experimental
implications, which are explored in methods involving B->DK decays. The
measurement sensitivity and new physics discovery potential are estimated using
a full Monte Carlo detector simulation with realistic background estimates.Comment: 15 pages, 2 figures, fixed typ
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