Artículos FISMAT-UBUhttp://hdl.handle.net/10259.4/25582024-03-28T09:27:20Z2024-03-28T09:27:20ZElectric Field Effects on Curved Graphene Quantum DotsHuerta Sainz, Sergio de laBallesteros Castañeda, ÁngelCordero Tejedor, Nicolás A.http://hdl.handle.net/10259/82202023-12-20T01:05:12Z2023-10-01T00:00:00ZElectric Field Effects on Curved Graphene Quantum Dots
Huerta Sainz, Sergio de la; Ballesteros Castañeda, Ángel; Cordero Tejedor, Nicolás A.
The recent and continuous research on graphene-based systems has opened their usage to a wide range of applications due to their exotic properties. In this paper, we have studied the effects of an electric field on curved graphene nanoflakes, employing the Density Functional Theory. Both mechanical and electronic analyses of the system have been made through its curvature energy, dipolar moment, and quantum regeneration times, with the intensity and direction of a perpendicular electric field and flake curvature as parameters. A stabilisation of non-planar geometries has been observed, as well as opposite behaviours for both classical and revival times with respect to the direction of the external field. Our results show that it is possible to modify regeneration times using curvature and electric fields at the same time. This fine control in regeneration times could allow for the study of new phenomena on graphene.
2023-10-01T00:00:00ZPsychometric Analysis and Contribution to the Evaluation of the Exams-Related Emotions Scale in Primary and Secondary School StudentsObregón Cuesta, Ana IsabelMínguez Mínguez, Luis AlbertoLeón del Barco, BenitoMendo-Lázaro, SantiagoFernández Solana, JessicaGonzález Santos, JosefaGonzález Bernal, Jerónimohttp://hdl.handle.net/10259/76022023-03-28T06:18:25Z2022-06-01T00:00:00ZPsychometric Analysis and Contribution to the Evaluation of the Exams-Related Emotions Scale in Primary and Secondary School Students
Obregón Cuesta, Ana Isabel; Mínguez Mínguez, Luis Alberto; León del Barco, Benito; Mendo-Lázaro, Santiago; Fernández Solana, Jessica; González Santos, Josefa; González Bernal, Jerónimo
The objective of this research was to perform a construct validity, and a psychometric
analysis of the Exams-related Emotions Scale (EES), analyze the differences in their scores regarding
gender and academic year in primary and secondary education student, as well as study the relationship between emotions and academic performance. During the construction and analysis of the
psychometric characteristics of the scale, an Exploratory Factor Analysis (EFA) and a Confirmatory
Factor Analysis (CFA) were performed. To test EES scores based on gender and school year, the
T-Student test for independent samples and ANOVA were used, respectively. To verify the relationship between the scores of the different types of emotions and academic performance, the Pearson
correlation test was performed. A total of 562 students belonging to the 5th (n = 228) and 6th (n = 186)
primary school year and the 1st (n = 134) and 2nd (n = 94) secondary school year participated in the
research. Age between 10 and 15 years old (mean = 11.66, standard deviation = 1.206) both males
(50.5%) and females (49.5%). The results offered support for the three-factor structure. The analysis
of invariance with respect to gender showed that the factor structure was invariant. Boys scored
higher on the positive emotions factor and lower scores on anxiety than girls. Regarding school
year, negative emotions and anxiety related to exams increase in the secondary courses compared
to Primary while for positive emotions it is primary school students who obtain higher scores. The
correlation coefficient between negative emotions (as well as anxiety) and school performance is
negative whereas the correlation coefficient between positive emotions and academic performance is
positive. EES scale is an instrument with scientific rigor and with adequate reliability and validity
to be able to know the emotions that primary and secondary school students suffer when they are
subjected to evaluation processes in the academic context.
2022-06-01T00:00:00ZCosmic Neutrinos as a Window to Departures from Special RelativityCarmona Martínez, José ManuelCortés Azcoiti, José LuisRelancio Martínez, José JavierReyes Hung, Maykoll Anthonnyhttp://hdl.handle.net/10259/75952023-04-19T10:44:34Z2022-06-01T00:00:00ZCosmic Neutrinos as a Window to Departures from Special Relativity
Carmona Martínez, José Manuel; Cortés Azcoiti, José Luis; Relancio Martínez, José Javier; Reyes Hung, Maykoll Anthonny
We review the peculiarities that make neutrinos very special cosmic messengers in highenergy astrophysics, and, in particular, to provide possible indications of deviations from special
relativity, as it is suggested theoretically by quantum gravity models. In this respect, we examine the
effects that one could expect in the production, propagation, and detection of neutrinos, not only in the
well-studied scenario of Lorentz Invariance Violation, but also in models which maintain, but deform,
the relativity principle, such as those considered in the framework of Doubly Special Relativity. We
discuss the challenges and the promising future prospects offered by this phenomenological window
to physics beyond special relativity.
2022-06-01T00:00:00ZGaussian Curvature Effects on Graphene Quantum DotsHuerta Sainz, Sergio de laBallesteros Castañeda, ÁngelCordero Tejedor, Nicolás A.http://hdl.handle.net/10259/75582023-12-19T09:12:58Z2022-12-01T00:00:00ZGaussian Curvature Effects on Graphene Quantum Dots
Huerta Sainz, Sergio de la; Ballesteros Castañeda, Ángel; Cordero Tejedor, Nicolás A.
In the last few years, much attention has been paid to the exotic properties that graphene
nanostructures exhibit, especially those emerging upon deforming the material. Here we present
a study of the mechanical and electronic properties of bent hexagonal graphene quantum dots
employing density functional theory. We explore three different kinds of surfaces with Gaussian
curvature exhibiting different shapes—spherical, cylindrical, and one-sheet hyperboloid—used to
bend the material, and several boundary conditions regarding what atoms are forced to lay on
the chosen surface. In each case, we study the curvature energy and two quantum regeneration
times (classic and revival) for different values of the curvature radius. A strong correlation between
Gaussian curvature and these regeneration times is found, and a special divergence is observed for
the revival time for the hyperboloid case, probably related to the pseudo-magnetic field generated by
this curvature being capable of causing a phase transition.
2022-12-01T00:00:00Z