5,159 research outputs found
Obtaining Au thin films in atmosphere of reactive nitrogen through magnetron sputtering
4d and 5d series of the transition metals are used to the obtaining nitrides metallic, due to the synthesis of PtN, AgN and AuN in the last years. Different nitrides are obtained in the Plasma Assisted Physics Vapour Deposition system, due to its ionization energy which is necessary for their formation. In this paper a Magnetron Sputtering system was used to obtain Au thin films on Si wafers in Nitrogen atmosphere. The substrate temperature was varied between 500 to 950°C. The samples obtained at high temperatures (>500°C) show Au, Si and N elements, as it is corroborated in the narrow spectrum obtained for X-Ray Photoelectron Spectroscopy; besides the competition of orientation crystallographic texture between (111) and (311) directions was present in the X-Ray Diffraction analysis to the sample heated at 950°C
Amalgamated products and properly 3-realizable groups
In this paper, we show that the class of all properly 3-realizable groups is
closed under amalgamated free products (and HNN-extensions) over finite groups.
We recall that is said to be properly 3-realizable if there exists a
compact 2-polyhedron with and whose universal cover
has the proper homotopy type of a 3-manifold (with boundary).Comment: J. Pure Appl. Alg., to appea
Comment on "Lattice Gluon and Ghost Propagators, and the Strong Coupling in Pure Yang-Mills Theory: Finite Lattice Spacing and Volume Effects"
The authors of ref. Phys.Rev. D94 (2016) no.1, 014502 reported about a
careful analysis of the impact of lattice artifacts on the gauge-field
propagators. In particular, they found that the low-momentum behavior of the
renormalized propagators depends on the lattice bare coupling and interpreted
this fact as the result of it being affected by finite lattice spacing
artifacts. We do not share this interpretation and present here a different and
more suitable explanation for these results
Are the low-momentum gluon correlations semiclassically determined?
We argue that low-energy gluodynamics can be explained in terms of
semi-classical Yang-Mills solutions by demonstrating that lattice gluon
correlation functions fit to instanton liquid predictions for low energies and,
after cooling, in the whole range.Comment: 4 pages, revtex
Coupled magnetic and elastic properties in LaPr(CaSr)MnO manganites
We investigate a series of manganese oxides, the
La0.225Pr0.4(Ca1-xSrx)0.375MnO3 system. The x = 0 sample is a prototype
compound for the study of phase separation in manganites, where ferromagnetic
and charge ordered antiferromagnetic phases coexist. Replacing Ca2+ by Sr2+
gradually turns the system into a homogeneous ferromagnet. Our results show
that the material structure plays a major role in the observed magnetic
properties. On cooling, at temperatures below 100 K, a strong contraction of
the lattice is followed by an increase in the magnetization. This is observed
both through thermal expansion and magnetostriction measurements, providing
distinct evidence of magneto-elastic coupling in these phase separated
compounds
Magnetocaloric effect in manganites: metamagnetic transitions for magnetic refrigeration
We present a study of the magnetocaloric effect in La5/8-yPryCa3/8MnO3
(y=0.3) and Pr0.5Ca0.09Sr0.41MnO3 manganites. The low temperature state of both
ystems is the result of a competition between the antiferromagnetic and
ferromagnetic phases. The samples display magnetocaloric effect evidenced in an
adiabatic temperature change during a metamagnetic transition from an
antiferromagnetic to a ferromagnetic phase . As additional features,
La5/8-yPryCa3/8MnO3 exhibits phase separation characterized by the coexistence
of antiferromagnetic and ferromagnetic phases and Pr0.5Ca0.09Sr0.41MnO3
displays inverse magnetocaloric effect in which temperature decreases while
applying an external magnetic field. In both cases, a significant part of the
magnetocaloric effect appears from non-reversible processes. As the traditional
thermodynamic description of the effect usually deals with reversible
transitions, we developed an alternative way to calculate the adiabatic
temperature change in terms of the change of the relative ferromagnetic
fraction induced by magnetic field. To evaluate our model, we performed direct
measurement of the sample's adiabatic temperature change by means of a
differential thermal analysis. An excellent agreement has been obtained between
experimental and calculated data. These results show that metamagnetic
transition in manganites play an important role in the study of magnetic
refrigeration.Comment: Acepted to be published in Applied Physics Letter
Weak -structures and one-relator groups
Motivated by the notion of boundary for hyperbolic and groups, M.
Bestvina in "Local Homology Properties of Boundaries of Groups" introduced the
notion of a (weak) -structure and (weak) -boundary for
a group of type (i.e., having a finite complex), with
implications concerning the Novikov conjecture for . Since then, some
classes of groups have been shown to admit a weak -structure (see
"Weak -structures for some classes of groups" by C.R. Guilbault for
example), but the question whether or not every group of type
admits such a structure remains open. In this paper, we show that every torsion
free one-relator group admits a weak -structure, by showing that
they are all properly aspherical at infinity; moreover, in the -ended case
the corresponding weak -boundary has the shape of either a circle
or a Hawaiian earring depending on whether the group is a virtually surface
group or not. Finally, we extend this result to a wider class of groups still
satisfying a Freiheitssatz property
Trauma exposure during immigration: important considerations for professionals working with Latina immigrant populations
Presentation made at Latinos in the Heartland (11th : 2013 : Columbia, Mo.) and published in the annual conference proceedings.Latina immigrants represent a population that has been historically under-served an exploited (Ojeda, Flores, Meza & Morales, 2011). Therefore, it is the responsibility of professionals that work with this vulnerable group to not further victimize or misuse research participants. This exploratory paper summarizes available literature relating to trauma experienced by Latina immigrants during migration and provides guidance for researchers and other professionals who work with Latina immigrant populations. It is important to note here, however, that the authors of this paper are not suggesting that severe trauma is necessarily a part of all Latina immigrant migration experiences. Rather, that they emphasize the point that this population is especially vulnerable. It is important that researchers and professionals working with Latina immigrants consider this topic
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