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Synthesis of molybdenum oxide nanoparticles by nanosecond laser ablation
Phothermal therapy (PTT) is one of the most promising techniques to treat cancer. Finding the ideal PTT agent nanomaterial has remained a challenge and has brought the interest of several researchers. In this work, we report the synthesis of molybdenum oxide (MoOx) nanoparticles (NPs), which exhibit absorption in the biological optical window ~840 nm, by using the laser ablation of solids in liquids (LASL) technique with nanosecond (ns) pulses. A Nd:YAG laser was used to synthesize the NPs in deionized (DI) water, free of surfactants or additives, which were optically characterized by absorption spectroscopy and TEM-EDX microscopy. Semi spherical NPs with a suitable average size and shape for potential use as PTT agents were obtained by laser ablation and ablation + fragmentation. The calculated band gap is 3.1 eV, which corresponds to MoO3. Micro-Raman spectroscopy studies determined that these NPs are composed of amorphous molybdenum oxide hydrates (MoO3 · xH2O)
Influence of oxygen pressure on the fs laserinduced oxidation of molybdenum thin films
We present a study of femtosecond (1028 nm, 230 fs, 54.7 MHz) laser processing on molybdenum (Mo) thin films. Irradiations were done under ambient air as well as pure oxygen (O2) at various gauge pressures (4, 8, 12 and 16 psi). Our results indicate that the high heating rates associated with laser processing allow the production of different molybdenum oxides. Raman spectroscopy and scanning electron microscopy are used to characterize the molybdenum oxidation for the different irradiation and oxygen pressures parameters chosen showing a high correlation between well-defined oxidation zones and the oxygen pressure surrounding the samples during the irradiation of the Mo thin films
Long-range correlations and trends in Colombian seismic time series
We study long-range correlations and trends in time series extracted from the
data of seismic events occurred from 1973 to 2011 in a rectangular region that
contains mainly all the continental part of Colombia. The long-range
correlations are detected by the calculation of the Hurst exponents for the
time series of interevent intervals, separation distances, depth differences
and magnitude differences. By using a modification of the classical
method that has been developed to detect short-range correlations in time
series, we find the existence of persistence for all the time series considered
except for magnitude differences. We find also, by using the until the
third order, that the studied time series are not influenced by trends.
Additionally, an analysis of the Hurst exponent as a function of the number of
events in the time and the maximum window size is presented.Comment: 21 pages, 6 figures, 2 figures added, types corrected, accepted to be
published in Physica
Invisibly Inked: An Intersectional Analysis of Tattooed Female Arrest Patterns
This project fills a gap in the literature of law enforcement response to a visible tattoo on a racialized female arrestee. With the increase in popularity of tattoos and their inherited status as a proxy for deviance, the entanglement of both racialized female bodies and symbols of deviance at the place of entry into the criminal justice system is significant. The racialized female body does not move without carrying the history of violence and inequality on it. As such, the entry of female bodies of Color into the criminal justice system is a time where capturing their experience is critical. In current law enforcement studies, the focus is on male offenders and Black male offenders using mainstream criminological perspectives. Additionally, the literature on arrest patterns of tattooed offenders, much less females of Color, is non-existent. Using an intersectional perspective, this project is a necessary analysis to fill this gap in the criminological body of knowledge
Realization of an all-optical zero to π cross-phase modulation jump
We report on the experimental demonstration of an all-optical π cross-phase modulation jump. By performing a preselection, an optically induced unitary transformation, and then a postselection on the polarization degree of freedom, the phase of the output beam acquires either a zero or π phase shift (with no other possible values). The postselection results in optical loss in the output beam. An input state may be chosen near the resulting phase singularity, yielding a pi phase shift even for weak interaction strengths. The scheme is experimentally demonstrated using a coherently prepared dark state in a warm atomic cesium vapor
Flavor-oscillation clocks, continuous quantum measurements and a violation of Einstein equivalence principle
The relation between Einstein equivalence principle and a continuous quantum
measurement is analyzed in the context of the recently proposed
flavor-oscillation clocks, an idea pioneered by Ahluwalia and Burgard (Gen. Rel
Grav. Errata 29, 681 (1997)). We will calculate the measurement outputs if a
flavor-oscillation clock, which is immersed in a gravitational field, is
subject to a continuous quantum measurement. Afterwards, resorting to the weak
equivalence principle, we obtain the corresponding quantities in a freely
falling reference frame. Finally, comparing this last result with the
measurement outputs that would appear in a Minkowskian spacetime it will be
found that they do not coincide, in other words, we have a violation of
Einstein equivalence principle. This violation appears in two different forms,
namely: (i) the oscillation frequency in a freely falling reference frame does
not match with the case predicted by general relativity, a feature previously
obtained by Ahluwalia; (ii) the probability distribution of the measurement
outputs, obtained by an observer in a freely falling reference frame, does not
coincide with the results that would appear in the case of a Minkowskian
spacetime.Comment: 16 pages, accepted in Mod. Phys. Letts.
Path integral approach to no-Coriolis approximation in heavy-ion collisions
We use the two time influence functional method of the path integral approach
in order to reduce the dimension of the coupled-channels equations for
heavy-ion reactions based on the no-Coriolis approximation. Our method is
superior to other methods in that it easily enables us to study the cases where
the initial spin of the colliding particle is not zero. It can also be easily
applied to the cases where the internal degrees of freedom are not necessarily
collective coordinates. We also clarify the underlying assumptions in our
approach.Comment: 11 pages, Latex, Phys. Rev. C in pres
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