9 research outputs found
Factors impacting the integration of one-to-one computing initiative into learning and teaching in Azerbaijan
During recent decades the educational community around the world has witnessed an
increasing interest in programmes aiming at providing teachers as well as learners of
all ages with direct access to personal computing devices and the vast amount of
information such provision enables. These types of programmes are known as âone-to-
one computingâ, a term that indicates a very widespread distribution of computers
in educational settings. Research into such patterns of provision has accordingly
become a priority. Understandably, the realities of one-to-one programme
implementation vary considerably across the nations, since cultural setting,
educational system, customs of technology use and teachersâ experiences are all
significant aspects that influence the process. However, there can be certain
commonalities across all these aspects in countries whose educational systems have a
largely shared history, as is the case in the former Soviet Union states. Azerbaijanâs
experience in the field, as one of the countries with a post-soviet educational system
going through curriculum reforms, was very attractive for a comprehensive study
with the primary focus on identifying the factors influencing the infusion of one-to-one
computing into learning and teaching.
The research question developed for this study was: âWhat factors influence the
integration of one-to-one computing into teaching and learning?â Qualitative
research methods were used to gather data at three purposively selected schools, two
in the capital city of Baku and one in a provincial town. The research data were
collected by conducting classroom observations, interviews and focus group
discussions with main stakeholders of the programme allowing for investigation of
studentsâ, teachersâ and parentsâ experiences throughout the implementation process.
Using a constructivist grounded theory approach the gathered data were analyzed in
two major stages: the first one employed the âhelicopter viewâ approach to attain a
preliminary picture, followed by the process of coding, memo-writing and analysis.
The second stage of the analysis resulted in a thematic summary into teacher, student
and classroom-dynamics-related categories.
The findings revealed that the students were the most enthusiastic about the changes
brought to the learning process with the introduction of the lightweight, small and
inexpensive devices, commonly known as netbooks. The students improved their
technological skills and knowledge and applied these skills in acquiring domain
knowledge. By providing students with netbooks, the one-to-one programme
introduced anytime, anywhere, and individualized learning opportunities. The study
also revealed that the introduction of netbooks was leading to students developing
collaborative learning skills. In addition, the study found that most of the teachers
were developing new teaching methods to continue the programme implementation.
They invested extra time and worked hard, notwithstanding the lack of guidelines
both on the integration of technology with pedagogy and on meeting newly-set
National Curriculum standards. Some teachers overcame the technological
challenges that arose along the way eagerly, while others used them as an excuse to
discontinue the programme implementation. The parentsâ opinions varied
considerably, some of them supported the innovation, while others considered the
frequent usage of technology excessive, unnecessary and potentially damaging to
their childrenâs health. The latter group of parents expected their children to be
taught similarly to them, with a primary focus on the development of handwriting
and speaking skills as well as the habits of reading printed books.
The research has identified eight major factors influencing the integration of one-to-one
computing into teaching and learning: embedding ICT in the curriculum,
fostering of exploratory learning, student satisfaction, new learning practices,
professional development, school leadership support, teacher beliefs and parental
support. Most importantly, the findings have revealed the importance of addressing
teacher professional development in terms of integrating technology with pedagogy
and meeting curriculum standards through technology-infused teaching methods.
These factors indicate the improvements needed for successful programme
implementation. It is hoped that the results can be adopted by educational leaders to
inform their decisions on one-to-one programmes, thereby contributing to successful
integration
Ultrafast Dynamics of Massive Dirac Fermions in Bilayer Graphene
Bilayer graphene is a highly promising material for electronic and
optoelectronic applications since it is supporting massive Dirac fermions with
a tuneable band gap. However, no consistent picture of the gap's effect on the
optical and transport behavior has emerged so far, and it has been proposed
that the insulating nature of the gap could be compromised by unavoidable
structural defects, by topological in-gap states, or that the electronic
structure could be altogether changed by many-body effects. Here we directly
follow the excited carriers in bilayer graphene on a femtosecond time scale,
using ultrafast time- and angle-resolved photoemission. We find a behavior
consistent with a single-particle band gap. Compared to monolayer graphene, the
existence of this band gap leads to an increased carrier lifetime in the
minimum of the lowest conduction band. This is in sharp contrast to the second
sub-state of the conduction band, in which the excited electrons decay through
fast, phonon-assisted inter-band transitions.Comment: 5 pages, 4 figure
Polarization Doping and Work Function of Epitaxial Graphene on Silicon Carbide
Graphen ist eine einatomar dĂŒnne Schicht von Kohlenstoffatomen mit besonderen elektronischen Eigenschaften. Epitaktisches Wachstum von Graphen auf der Silizium-terminierten OberflĂ€che von Siliziumkarbid (SiC) wird weithin als eine der geeignetsten Methoden zur Herstellung von groĂflĂ€chigem Graphen fĂŒr elektronische Anwendungen angesehen.
In dieser Arbeit werden verschiedene Dotierungsmechanismen von Graphen auf SiC theoretisch beschrieben und experimentell untersucht. Auf der Silizium-terminierten SiC-OberflĂ€che gewachsenes Graphen besitzt einen Ăberschuss an Elektronen (n-Dotierung). Wird die SiC/Graphen-GrenzflĂ€che mit Wasserstoff passiviert und das Graphen vom Substrat entkoppelt, liegt dagegen Löcherleitung vor (p-Dotierung). Die p-Dotierung von quasifreistehendem Graphen (QFG) auf hexagonalem SiC wird durch die spontane Polarisation des Substrats erklĂ€rt. Dieser Mechanismus basiert auf einer Volumeneigenschaft von SiC, die bei jeden hexagonalem Polytyp des Materials vorhanden und unabhĂ€ngig von Einzelheiten der GrenzflĂ€chenbildung ist. Die n-Dotierung des epitaktischen Graphens (EG) wird durch GrenzflĂ€chenzustĂ€nde erklĂ€rt, die die Polarisationsdotierung ĂŒberkompensieren.
Die Austrittsarbeit und elektronische Struktur von EG sowie QFG werden ebenfalls untersucht. Es wird beobachtet, dass die Austrittsarbeit gegen den Wert von Graphit konvergiert, wenn die Anzahl der Graphenschichten erhöht wird. AuĂerdem, Messungen der OberflĂ€chenphotospannung werden im Zusammenhang mit verschiedenen Rekombinationsraten an der GrenzflĂ€che von EG und QFG diskutiert
Polarization Doping and Work Function of Epitaxial Graphene on Silicon Carbide
Graphen ist eine einatomar dĂŒnne Schicht von Kohlenstoffatomen mit besonderen elektronischen Eigenschaften. Epitaktisches Wachstum von Graphen auf der Silizium-terminierten OberflĂ€che von Siliziumkarbid (SiC) wird weithin als eine der geeignetsten Methoden zur Herstellung von groĂflĂ€chigem Graphen fĂŒr elektronische Anwendungen angesehen.
In dieser Arbeit werden verschiedene Dotierungsmechanismen von Graphen auf SiC theoretisch beschrieben und experimentell untersucht. Auf der Silizium-terminierten SiC-OberflĂ€che gewachsenes Graphen besitzt einen Ăberschuss an Elektronen (n-Dotierung). Wird die SiC/Graphen-GrenzflĂ€che mit Wasserstoff passiviert und das Graphen vom Substrat entkoppelt, liegt dagegen Löcherleitung vor (p-Dotierung). Die p-Dotierung von quasifreistehendem Graphen (QFG) auf hexagonalem SiC wird durch die spontane Polarisation des Substrats erklĂ€rt. Dieser Mechanismus basiert auf einer Volumeneigenschaft von SiC, die bei jeden hexagonalem Polytyp des Materials vorhanden und unabhĂ€ngig von Einzelheiten der GrenzflĂ€chenbildung ist. Die n-Dotierung des epitaktischen Graphens (EG) wird durch GrenzflĂ€chenzustĂ€nde erklĂ€rt, die die Polarisationsdotierung ĂŒberkompensieren.
Die Austrittsarbeit und elektronische Struktur von EG sowie QFG werden ebenfalls untersucht. Es wird beobachtet, dass die Austrittsarbeit gegen den Wert von Graphit konvergiert, wenn die Anzahl der Graphenschichten erhöht wird. AuĂerdem, Messungen der OberflĂ€chenphotospannung werden im Zusammenhang mit verschiedenen Rekombinationsraten an der GrenzflĂ€che von EG und QFG diskutiert
Polarization doping of graphene on silicon carbide
The doping of quasi-freestanding graphene (QFG) on H-terminated, Si-face 6H-, 4H-, and 3C-SiC is studied by angle-resolved photoelectron spectroscopy (ARPES) close to the Dirac point. Using semi-insulating as well as n-type doped substrates we shed light on the contributions to the charge carrier density in QFG caused by i) the spontaneous polarization of the substrate, and ii) the band alignment between the substrate and the graphene layer. In this way we provide quantitative support for the previously suggested model of polarization doping of graphene on SiC [Phys. Rev. Lett. 108, 246104 (2012)]
Electronic structure and dielectric function of Mn-Bi-Te layered compounds
A comparative study of the electronic and optical properties of Mn-Bi-Te layered compounds was carried out using spectroscopic ellipsometry (SE) over a photon energy range of 0.7-6.5 eV at room temperature and density functional theory (DFT)-based first-principle calculations within the general gradient approximation with Hubbard like correction (GGA+U) and allowance for a spin-orbital coupling. The total energies of the above compounds in ferromagnetic (FM) and antiferromagnetic (AFM) spin configurations are obtained by taking the long-range van der Waals interaction into account. The stability of the AFM state of MnBiTe and MnBiTe over the corresponding FM counterpart is disclosed. The SE-based and calculated dielectric functions are compared. It is shown that interband optical transitions in the accessed photon energy range mainly occur between Mn 3d + Te 5p states of the valence band and Bi 6p + Te 5p with a small admixture of Mn 3d states of the conduction band.We acknowledge the support by the Science Development Foundation under the President of the Republic of Azerbaijan (Grant No. EI F-BGM-4-RFTF1/2017-21/04/1-M-02), Russian Foundation for Basic Research (Grant No. 18-52-06009), the Basque Departamento de EducaciĂłn, UPV/EHU (Grant No. IT-756-13), Spanish Ministerio de Economia y Competitividad (MINECO Grant No. FIS2016-75862-P), the Saint Petersburg State University grant for scientific investigations (Grant No.15.61.202.2015). M.M.O. acknowledges support by the DiputaciĂłn Foral de Gipuzkoa (SAREA 2018 - RED 2018*, *Project No. 2018-CIEN-000025-01)
Infrared spectroscopic ellipsometry and optical spectroscopy of plasmons in classic 3D topological insulators
Narrow bandgap BiSe, BiTe, and SbTe, commonly referred to as classic 3D topological insulators, were studied at room temperature by spectroscopic ellipsometry and optical reflection spectroscopy over the mid-IR-near-infrared photon energy range. Complementarily, Hall measurements were performed. Plasmons in optical loss function and reflection coefficient were identified. The conventional approach based on the high frequency dielectric constant was shown to work well in the description of plasmons in BiSe and SbTe and to fail in the case of a similar compound, BiTe. The obtained results are discussed in terms of single- and multivalley approaches to the studied samples with taking the details of the calculated band structure into account.This work was supported by the Science Development Foundation under the President of the Republic of Azerbaijan (Grant No. EI F-BGM-4-RFTF1/2017-21/04/1-M-02 and EÄ°F-BGM-3-BRFTF-2+/2017-15/02/1), the Russian Foundation for Basic Research (Grant No. 18-52-06009), and the Saint Petersburg State University grant for scientific investigations (Grant No. 15.61.202.2015)
Modification of optical properties of PC-PBT/Cr 2
Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20â110âkGy) of Îł radiation. The induced modifications in the optical properties of the Îł irradiated NCPs have been studied as a function of Îł dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon Îł irradiation up to 110âkGy, while it decreased from 4.26 to 4.14âeV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ÎE has been computed; results show that both the two synthesized NCPs have a response to color alteration by Îł irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ÎE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells