THE EFFICIENCY OF THE USE OF INDIVIDUAL REMOVABLE DENTAL BITE SPLINTS FOR CORRECTION OF DENTAL DEFORMATIONS DEGREE IN PATIENTS WITH DENTURE DEFECTS

Objective: introduction of prevention methods and increase of the treatment efficacy of teeth deformations using individual dental bite splints. Materials and methods: The results of clinical examination of 67 patients of different age (20 to 59 years) with the existing dentition defects before and after use of individual removable dental bite splints are given in this article. The results of the work: the objective study showed a difference in data of the distances between certain points of the teeth surrounding the defect without dentition deformations and in their presence (distances АВ in the control and experimental groups was respectively 7.16 ± 0.19 mm and 4.32 ± 0.19 mm, АD -7.62 ± 0.19 mm and 4.16 ± 0.20 mm, ВС - 7.49 ± 0.19 mm and 4.07 ± 0.19 mm, СD – 6.96±0.19 mm and 3.67±0.19 mm). After the performance of the preparation of the patients with the dentition defects and deformations of the teeth with the use of individual dental bite splints to the prosthetic repair in several stages, it became possible to reduce significantly indexes of the distances in the presence of pathology and bring them closer to physiological data (АВ - 5.85 ± 0.21 mm, AD - 6.09 ± 0.18 mm, BC - 6.22 ± 0.19 mm, and СD- 5.73±0.19mm). Conclusions: The use of individual removable dental bite splints gave the possibility to improve significantly the prosthetic efficacy by normalizing the occlusal relations and chewing load onto the displaced teeth in the area of dentition defect

Quantum confined acceptors and donors in InSe nanosheets

We report on the radiative recombination of photo-excited carriers bound at native donors and acceptors in exfoliated nanoflakes of nominally undoped rhombohedral gamma-polytype InSe. The binding energies of these states are found to increase with the decrease in flake thickness, L. We model their dependence on L using a two-dimensional hydrogenic model for impurities and show that they are strongly sensitive to the position of the impurities within the nanolayer. (c) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License

An innovative and viable routre for the realization of ultra-thin supercapacitor electrodes assembled with carbon nanotubes

Electrochemical Double Layer Capacitors (EDLC), also known as supercapacitors, have been fabricated using Single Walled Carbon Nanotubes (SWCNTs) as active material for electrode assembling. In particular a new way of fabrication of ultra-thin electrodes (≤25 m) directly formed on the separator has been proposed, and a prototype of EDLC has been realized and tested. For such devices the specific capacitance is in the range 40–45 F/g and the internal resistances in the range 6–8 ·cm2, at current density of 2 mA·cm−2. Keywords: Carbon Nanotube, Supercapacito

Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

The temperature effect on the Raman scattering efficiency is investigated in ε-GaSe and γ-InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone. Two-dimensional (2D) van der Waals crystals have recently attracted considerable attention due to their unique electronic band structure and functionalities 1,2. The main focus of researchers has been on semiconducting transition metal dichalcogenides (S-TMDs), e.g. MoS 2 , WSe 2 , and MoTe 2 3,4. Currently, another much larger group of layered materials, i.e. semiconducting post-transition metal chalcogenides (S-PTMCs), e.g. SnS, GaS, InSe, and GaTe, has drawn the attention of the 2D community. Among these crystals, Se-based compounds of S-PTMCs, i.e. InSe and GaSe, demonstrate a tunability of their optical response from the near infrared to the visible spectrum with decreasing layer thickness down to monolayers 5-7. Raman scattering (RS) spectroscopy is a powerful and nondestructive tool to get useful information about material properties 8. The RS measurements provide an insight into their vibrational and electronic structures and are of particular importance in studies of layered materials 9. The flake thickness, strain, stability, charge transfer, stoichiometry, and stacking orders of the layers can be accessed by monitoring parameters of the observed pho-non modes 10-17. RS experiments can be performed under non-resonant and resonant excitation conditions: 18. The resonant excitation may lead to a significant enhancement of the RS intensity in S-TMD as well as the activation of otherwise inactive modes. This offers supplementary information on the coupling of particular phonons to electronic transitions of a specific symmetry 19-21. The crossover between the non-resonant and resonant conditions can be achieved not only by the variation of the excitation energy but also by the modulation of temperature as it was recently reported 22-24. In such an approach, it is the band structure that changes with temperature allowing for resonance with particular excitation energy. In this work, we present a comprehensive investigation of the effect of temperature on the Raman scattering in ε-GaSe and γ-InSe crystals. It has been found that the intensity of some phonon modes exhibits a strong variation as a function of temperature under excitation with specific energy due to the resonant conditions of RS. Moreover, a significant antiresonance behaviour accompanies the resonances at higher temperatures, which leads to the vanishing of the modes intensities. The observed effects are discussed in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone (BZ)

Tunable spin-orbit coupling in two-dimensional InSe

We demonstrate that spin-orbit coupling (SOC) strength for electrons near the conduction band edge in few-layer γ-InSe films can be tuned over a wide range. This tunability is the result of a competition between film-thickness-dependent intrinsic and electric-field-induced SOC, potentially, allowing for electrically switchable spintronic devices. Using a hybrid k · p tight-binding model, fully parameterized with the help of density functional theory computations, we quantify SOC strength for various geometries of InSe-based field-effect transistors. The theoretically computed SOC strengths are compared with the results of weak antilocalization measurements on dual-gated multilayer InSe films, interpreted in terms of Dyakonov-Perel spin relaxation due to SOC, showing a good agreement between theory and experiment

Terahertz control of photoluminescence emission in few-layer InSe

A promising route for the development of opto-electronic technology is to use terahertz radiation to modulate the optical properties of semiconductors. Here, we demonstrate the dynamical control of photoluminescence (PL) emission in few-layer InSe using picosecond terahertz pulses. We observe a strong PL quenching (up to 50%) after the arrival of the terahertz pulse followed by a reversible recovery of the emission on the timescale of 50 ps at T = 10 K. Microscopic calculations reveal that the origin of the photoluminescence quenching is the terahertz absorption by photo-excited carriers: this leads to a heating of the carriers and a broadening of their distribution, which reduces the probability of bimolecular electron-hole recombination and, therefore, the luminescence. By numerically evaluating the Boltzmann equation, we are able to clarify the individual roles of optical and acoustic phonons in the subsequent cooling process. The same PL quenching mechanism is expected in other van der Waals semiconductors, and the effect will be particularly strong for materials with low carrier masses and long carrier relaxation time, which is the case for InSe. This work gives a solid background for the development of opto-electronic applications based on InSe, such as THz detectors and optical modulators

Highly-mismatched InAs/InSe heterojunction diodes

We report on heterojunction diodes prepared by exfoliation and direct mechanical transfer of a p-type InSe thin film onto an n-type InAs epilayer. We show that despite the different crystal structures and large lattice mismatch (34%) of the component layers, the junctions exhibit rectification behaviour with rectification ratios of 10[superscript]4 at room temperature and broad-band photoresponse in the near infrared and visible spectral ranges