1,718 research outputs found
Multiplicative stochastic heat equations on the whole space
We carry out the construction of some ill-posed multiplicative stochastic heat equations on unbounded domains. The two main equations our result covers are the parabolic Anderson model on R3, and the KPZ equation on R via the Cole–Hopf transform. To perform these constructions, we adapt the theory of regularity structures to the setting of weighted Besov spaces. One particular feature of our construction is that it allows one to start both equations from a Dirac mass at the initial time
Pressure-induced hole doping of the Hg-based cuprate superconductors
We investigate the electronic structure and the hole content in the
copper-oxygen planes of Hg based high Tc cuprates for one to four CuO2 layers
and hydrostatic pressures up to 15 GPa. We find that with the pressure-induced
additional number of holes of the order of 0.05e the density of states at the
Fermi level changes approximately by a factor of 2. At the same time the saddle
point is moved to the Fermi level accompanied by an enhanced k_z dispersion.
This finding explains the pressure behavior of Tc and leads to the conclusion
that the applicability of the van Hove scenario is restricted. By comparison
with experiment, we estimate the coupling constant to be of the order of 1,
ruling out the weak coupling limit.Comment: 4 pages, 4 figure
SiNx:Tb3+--Yb3+, an efficient down-conversion layer compatible with a silicon solar cell process
SiN x : Tb 3+-Yb 3+, an efficient down-conversion layer compatible with
silicon solar cell process Abstract Tb 3+-Yb 3+ co-doped SiN x down-conversion
layers compatible with silicon Photovoltaic Technology were prepared by
reactive magnetron co-sputtering. Efficient sensitization of Tb 3+ ions through
a SiN x host matrix and cooperative energy transfer between Tb 3+ and Yb 3+
ions were evidenced as driving mechanisms of the down-conversion process. In
this paper, the film composition and microstructure are investigated alongside
their optical properties, with the aim of maximizing the rare earth ions
incorporation and emission efficiency. An optimized layer achieving the highest
Yb 3+ emission intensity was obtained by reactive magnetron co-sputtering in a
nitride rich atmosphere for 1.2 W/cm and 0.15 W/cm power density
applied on the Tb and Yb targets, respectively. It was determined that
depositing at 200 {\textdegree}C and annealing at 850 {\textdegree}C leads to
comparable Yb 3+ emission intensity than depositing at 500 {\textdegree}C and
annealing at 600 {\textdegree}C, which is promising for applications toward
silicon solar cells.Comment: Solar Energy Materials and Solar Cells, Elsevier, 201
Discovery of a dark, massive, ALMA-only galaxy at z~5-6 in a tiny 3-millimeter survey
We report the serendipitous detection of two 3 mm continuum sources found in
deep ALMA Band 3 observations to study intermediate redshift galaxies in the
COSMOS field. One is near a foreground galaxy at 1.3", but is a previously
unknown dust-obscured star-forming galaxy (DSFG) at probable ,
illustrating the risk of misidentifying shorter wavelength counterparts. The
optical-to-mm spectral energy distribution (SED) favors a grey
attenuation curve and results in significantly larger stellar mass and SFR
compared to a Calzetti starburst law, suggesting caution when relating
progenitors and descendants based on these quantities. The other source is
missing from all previous optical/near-infrared/sub-mm/radio catalogs
("ALMA-only"), and remains undetected even in stacked ultradeep optical
( AB) and near-infrared ( AB) images. Using the ALMA position as
a prior reveals faint measurements in stacked IRAC 3.6+4.5,
ultradeep SCUBA2 850m, and VLA 3GHz, indicating the source is real. The
SED is robustly reproduced by a massive M and
M, highly obscured , star forming
Myr galaxy at redshift 1.1. The
ultrasmall 8 arcmin survey area implies a large yet uncertain
contribution to the cosmic star formation rate density CSFRD(z=5)
M yr Mpc, comparable to all
ultraviolet-selected galaxies combined. These results indicate the existence of
a prominent population of DSFGs at , below the typical detection limit of
bright galaxies found in single-dish sub-mm surveys, but with larger space
densities Mpc, higher duty cycles ,
contributing more to the CSFRD, and potentially dominating the high-mass galaxy
stellar mass function.Comment: Accepted for publication in ApJ. 2 galaxies, too many pages, 8
figures, 2 table
Synthesis and characterization of La<sub>0.8</sub>Sr<sub>1.2</sub>Co<sub>0.5</sub>M<sub>0.5</sub>O<sub>4-?</sub> (M=Fe, Mn)
The M4+-containing K2NiF4-type phases La0.8Sr1.2Co0.5Fe0.5O4 and La0.8Sr1.2Co0.5Mn0.5O4 have been synthesized by a sol-gel procedure and characterized by X-ray powder diffraction, thermal analysis, neutron powder diffraction and Mössbauer spectroscopy. Oxide ion vacancies are created in these materials via reduction of M4+ to M3+ and of Co3+ to Co2+. The vacancies are confined to the equatorial planes of the K2NiF4-type structure. A partial reduction of Mn3+ to Mn2+ also occurs to achieve the oxygen stoichiometry in La0.8Sr1.2Co0.5Mn0.5O3.6. La0.8Sr1.2Co0.5Fe0.5O3.65 contains Co2+ and Fe3+ ions which interact antiferromagnetically and result in noncollinear magnetic order consistent with the tetragonal symmetry. Competing ferromagnetic and antiferromagnetic interactions in La0.8Sr1.2Co0.5Fe0.5O4, La0.8Sr1.2Co0.5Mn0.5O4 and La0.8Sr1.2Co0.5Mn0.5O3.6 induce spin glass properties in these phases
The reconstruction theorem in Besov spaces
The theory of regularity structures [9] sets up an abstract framework of modelled distributions generalising the usual Hölder functions and allowing one to give a meaning to several ill-posed stochastic PDEs. A key result in that theory is the so-called reconstruction theorem: it defines a continuous linear operator that maps spaces of modelled distributions into the usual space of distributions. In the present paper, we extend the scope of this theorem to analogues to the whole class of Besov spaces Bp,qγ with non-integer regularity indices. We then show that these spaces behave very much like their classical counterparts by obtaining the corresponding embedding theorems and Schauder-type estimates
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