389,130 research outputs found
Optical spectroscopy study of Nd(O,F)BiS2 single crystals
We present an optical spectroscopy study on F-substituted NdOBiS
superconducting single crystals grown using KCl/LiCl flux method. The
measurement reveals a simple metallic response with a relatively low screened
plasma edge near 5000 \cm. The plasma frequency is estimated to be 2.1 eV,
which is much smaller than the value expected from the first-principles
calculations for an electron doping level of x=0.5, but very close to the value
based on a doping level of 7 of itinerant electrons per Bi site as
determined by ARPES experiment. The energy scales of the interband transitions
are also well reproduced by the first-principles calculations. The results
suggest an absence of correlation effect in the compound, which essentially
rules out the exotic pairing mechanism for superconductivity or scenario based
on the strong electronic correlation effect. The study also reveals that the
system is far from a CDW instability as being widely discussed for a doping
level of x=0.5.Comment: 5 pages, 5 figure
Background stratospheric aerosol reference model
In this analysis, a reference background stratospheric aerosol optical model is developed based on the nearly global SAGE 1 satellite observations in the non-volcanic period from March 1979 to February 1980. Zonally averaged profiles of the 1.0 micron aerosol extinction for the tropics and the mid- and high-altitudes for both hemispheres are obtained and presented in graphical and tabulated form for the different seasons. In addition, analytic expressions for these seasonal global zonal means, as well as the yearly global mean, are determined according to a third order polynomial fit to the vertical profile data set. This proposed background stratospheric aerosol model can be useful in modeling studies of stratospheric aerosols and for simulations of atmospheric radiative transfer and radiance calculations in atmospheric remote sensing
Detecting and diagnosing faults in dynamic stochastic distributions using a rational b-splines approximation to output PDFs
Describes the process of detecting and diagnosing faults in dynamic stochastic distributions using a rational b-splines approximation to output PDFs
Optimizing Associative Information Transfer within Content-addressable Memory
Original article can be found at: http://www.oldcitypublishing.com/IJUC/IJUC.htmlPeer reviewe
Semimetallic molecular hydrogen at pressure above 350 GPa
According to the theoretical predictions, insulating molecular hydrogen
dissociates and transforms to an atomic metal at pressures P~370-500 GPa. In
another scenario, the metallization first occurs in the 250-500 GPa pressure
range in molecular hydrogen through overlapping of electronic bands. The
calculations are not accurate enough to predict which option is realized. Here
we show that at a pressure of ~360 GPa and temperatures <200 K the hydrogen
starts to conduct, and that temperature dependence of the electrical
conductivity is typical of a semimetal. The conductivity, measured up to 440
GPa, increases strongly with pressure. Raman spectra, measured up to 480 GPa,
indicate that hydrogen remains a molecular solid at pressures up to 440 GPa,
while at higher pressures the Raman signal vanishes, likely indicating further
transformation to a good molecular metal or to an atomic state
Blaschke's problem for timelike surfaces in pseudo-Riemannian space forms
We show that isothermic surfaces and S-Willmore surfaces are also the
solutions to the corresponding Blaschke's problem for both spacelike and
timelike surfaces in pseudo-Riemannian space forms. For timelike surfaces both
Willmore and isothermic, we obtain a description by minimal surfaces similar to
the classical results of Thomsen.Comment: 10 page
Cooling of Nanomechanical Resonator Based on Periodical Coupling to Cooper Pair Box
We propose and study an active cooling mechanism for the nanomechanical
resonator (NAMR) based on periodical coupling to a Cooper pair box (CPB), which
is implemented by a designed series of magnetic flux pluses threading through
the CPB. When the initial phonon number of the NAMR is not too large, this
cooling protocol is efficient in decreasing the phonon number by two to three
orders of magnitude. Our proposal is theoretically universal in cooling various
boson systems of single mode. It can be specifically generalized to prepare the
nonclassical state of the NAMR.Comment: 5pages,3figure
The NJL model and strange quark matter
The stability of strange quark matter is studied within the Nambu
Jona-Lasinio model with three different parameter sets. The model Lagrangian
contains 4-fermion (with and without vector interaction) and 6-fermion terms;
the minimum energy per baryon number as a function of the strangeness fraction
of the system is compared to the masses of hyperons having the same strangeness
fraction, and coherently calculated in the same version of the model, and for
the same parameter set. The results show that in none of the different
parameter sets strangelets are stable, and in some cases a minimum in the
energy per baryon does not even exist.Comment: 8 pages, 2 figures, reference added, typos corrected, version to
appear in Europhys. Let
Quantum CPU and Quantum Algorithm
Making use of an universal quantum network -- QCPU proposed by
me\upcite{My1}, it is obtained that the whole quantum network which can
implement some the known quantum algorithms including Deutsch algorithm,
quantum Fourier transformation, Shor's algorithm and Grover's algorithm.Comment: 8 pages, Revised Versio
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