scholarly journals Advances in electromagnetic applications and communications

TecnoLógicas ◽  
2018 ◽  
Vol 21 (43) ◽  
pp. 9-13 ◽  
Author(s):  
Erick Reyes-Vera ◽  
David E. Senior ◽  
José Martín Luna-Rivera ◽  
Francisco Eugenio López-Giraldo
Keyword(s):  
Communication Systems ◽  
Visible Region ◽  
Infrared Region ◽  
Electromagnetic Spectrum ◽  
Radio Waves ◽  
Spectrum Radio

Modern communication systems have traditionally exploited three parts of the electromagnetic spectrum: radio waves region, infrared region and visible region, where the evolution in these ranges is always accompanied by the appropriation of new electromagnetic phenomena to build devices with better characteristics. In these three regions great advances have been conducted in recent years. For this reason, in this issue, we call for papers concerning to the major challenges that these technologies may face in the coming years. 

scholarly journals Utilization of the Radiofrequency Spectrum above 1 GHz by Passive Services

2001 ◽  
Vol 196 ◽  
pp. 255-263 ◽  
Author(s):  
Juan R. Pardo ◽  
Pierre J. Encrenaz ◽  
Daniel Breton
Keyword(s):  
Electromagnetic Spectrum ◽  
Radio Waves ◽  
Frequency Bands ◽  
Human Control ◽  
Naturally Occurring ◽  
Spectrum Radio ◽  
Active Service ◽  
Active Services ◽  
Cosmic Origin ◽  
Longwave Region

Microwave atmospheric radiometry and radio, mm and sub-mm astronomy are “passive” services, i.e. not involved in any man-made transmission but only concerned with the reception of naturally occurring radio waves. The intensity of the radiation received is not subject to human control, unlike the situation for active services. All active services operate in bands occupied by natural signals of atmospheric and cosmic origin and the active service tranmissions may be powerful enough to noticeably interfere with reception of those signals by scientific services. A conflict exists for the coexistence of active and passive services in many frequency bands, which leads to a need for regulating how to share the electromagnetic spectrum. This document gives an overview of the problems of frequency sharing in the longwave region of the electromagnetic spectrum (radio to submillimetre waves).

scholarly journals Porous Silicon and Indium Doped Zinc Oxide Junctions: Synthesis, Characterization, and Application to Electroluminescent Devices

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
F. Severiano ◽  
G. García ◽  
L. Castañeda ◽  
V. L. Gayou
Keyword(s):  
Zinc Oxide ◽  
Porous Silicon ◽  
Visible Region ◽  
Electrical Characterization ◽  
Precursor Solution ◽  
Infrared Region ◽  
Dip Coating ◽  
Electromagnetic Spectrum ◽  
Sem Images ◽  
Electroluminescent Devices

We report the obtaining of electroluminescent devices (ELD) from porous silicon (PS) and indium doped zinc oxide (ZnO:In) junctions. PS presented photoluminescence (PL) in the visible region of the electromagnetic spectrum. ZnO:In thin film was obtained by dip coating technique. SEM images and IR measurements showed the incorporation of the ZnO:In in the PS structure. Once obtained, the device was optically and electrically characterized. The ELD showed emission in the visible (450–850 nm) and infrared region (900–1200 nm) where it was electrically polarized. The visible emission was detected as luminescent spots on the surface. Electrical characterization was carried out by current-voltage (I-V) curves. The I-V curves showed rectifying behavior. It was related to the quenching of the EL with the process that takes place in the PS when it was immersed in the precursor solution of the ZnO:In.

scholarly journals Electronic, Structural, and Optical Structure of Mono-Doped and Co-Doped (210) TiO2 Brookite Surfaces for Application in Dye-Sensitized Solar Cells—A First Principles Study

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3918
Author(s):  
Ratshilumela S. Dima ◽  
Lutendo Phuthu ◽  
Nnditshedzeni E. Maluta ◽  
Joseph K. Kirui ◽  
Rapela R. Maphanga
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Dye Sensitized Solar Cells ◽  
Visible Region ◽  
Electromagnetic Spectrum ◽  
Doped Tio2 ◽  
Dye Sensitized ◽  
Sensitized Solar Cells ◽  
Co Doped ◽  
Optical Structure

Titanium dioxide (TiO2) polymorphs have recently gained a lot of attention in dye-sensitized solar cells (DSSCs). The brookite polymorph, among other TiO2 polymorphs, is now becoming the focus of research in DSSC applications, despite the difficulties in obtaining it as a pure phase experimentally. The current theoretical study used different nonmetals (C, S and N) and (C-S, C-N and S-N) as dopants and co-dopants, respectively, to investigate the effects of mono-doping and co-doping on the electronic, structural, and optical structure properties of (210) TiO2 brookite surfaces, which is the most exposed surface of brookite. The results show that due to the narrowing of the band gap and the presence of impurity levels in the band gap, all mono-doped and co-doped TiO2 brookite (210) surfaces exhibit some redshift. In particular, the C-doped, and C-N co-doped TiO2 brookite (210) surfaces exhibit better absorption in the visible region of the electromagnetic spectrum in comparison to the pure, S-doped, N-doped, C-S co-doped and N-S co-doped TiO2 brookite (210) surfaces.

scholarly journals Propagation Channel Measurements in the mm- and Sub-mm Wave Range for Different Indoor Communication Scenarios

2021 ◽  
Vol 42 (4) ◽  
pp. 357-370
Author(s):  
M. A. Salhi ◽  
T. Kleine-Ostmann ◽  
T. Schrader
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Wireless Communication Systems ◽  
Electromagnetic Spectrum ◽  
Channel Measurements ◽  
Frequency Range ◽  
Propagation Channel ◽  
Data Rates ◽  
Indoor Wireless ◽  
Wave Range

AbstractIncreasing data rates in wireless communications are accompanied with the need for new unoccupied and unregulated bandwidth in the electromagnetic spectrum. Higher carrier frequencies in the lower THz frequency range might offer the solution for future indoor wireless communication systems with data rates of 100 Gbit/s and beyond that cannot be located elsewhere. In this review, we discuss propagation channel measurements in an extremely broad frequency range from 50 to 325 GHz in selected indoor communication scenarios including kiosk downloading, office room communication, living rooms, and typical industrial environments.

scholarly journals Design and fabrication of a semi-transparent solar cell considering the effect of the layer thickness of MoO3/Ag/MoO3 transparent top contact on optical and electrical properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Çağlar Çetinkaya ◽  
Erman Çokduygulular ◽  
Barış Kınacı ◽  
Feyza Güzelçimen ◽  
Yunus Özen ◽  
...  
Keyword(s):  
Solar Cell ◽  
Layer Thickness ◽  
High Performance ◽  
Near Infrared ◽  
Visible Region ◽  
Infrared Region ◽  
Experimental Comparison ◽  
Top Contact ◽  
Cie Chromaticity ◽  
Design And Manufacture

AbstractWe conducted the present study to design and manufacture a semi-transparent organic solar cell (ST-OSC). First, we formed a transparent top contact as MoO3/Ag/MoO3 in a dielectric/metal/dielectric (DMD) structure. We performed the production of an FTO/ZnO/P3HT:PCBM/MoO3/Ag/MoO3 ST-OSC by integrating MoO3/Ag/MoO3 (10/$$d_{m}$$ d m /$$d_{{od}}$$ d od nm) instead of an Ag electrode in an opaque FTO/ZnO/P3HT:PCBM/MoO3/Ag (–/40/130/10/100 nm) OSC, after theoretically achieving optimal values of optical and electrical parameters depending on Ag layer thickness. The transparency decreased with the increase of $$d_{m}$$ d m values for current DMD. Meanwhile, maximum transmittance and average visible transmittance (AVT) indicated the maximum values of over 92% for $$d_{m} ~$$ d m  = 4 and 8 nm, respectively. For ST-OSCs, the absorption and reflectance increased in the visible region by a wavelength of longer than 560 nm and in the whole near-infrared region by increasing $$d_{m}$$ d m up to 16 nm. Moreover, in the CIE chromaticity diagram, we reported a shift towards the D65 Planckian locus for colour coordinates of current ST-OSCs. Electrical analysis indicated the photogenerated current density and AVT values for $$d_{m} = 6$$ d m = 6  nm as 63.30 mA/cm2 and 38.52%, respectively. Thus, the theoretical and experimental comparison of optical and electrical characteristics confirmed that the manufactured structure is potentially conducive for a high-performance ST-OSC.

Emergent chiroptical properties in supramolecular and plasmonic assemblies

2021 ◽  
Author(s):  
N. S. Shahana Nizar ◽  
Meleppatt Sujith ◽  
K. Swathi ◽  
Cristina Sissa ◽  
Anna Painelli ◽  
...  
Keyword(s):  
Visible Region ◽  
Electromagnetic Spectrum ◽  
Comprehensive Description ◽  
Chiroptical Properties ◽  
Uv Visible

This tutorial provides a comprehensive description of the origin of chiroptical properties of supramolecular and plasmonic assemblies in the UV–visible region of the electromagnetic spectrum.

scholarly journals Non-surgical treatments of complications after dental implantation. Perspectives for infrared laser light in the treatment of mucositis and peri-implantitis

2020 ◽  
Vol 24 (1) ◽  
pp. 49-56
Author(s):  
I. N. Razina ◽  
L. M. Lomiashvili ◽  
V. B. Nedoseko
Keyword(s):  
Laser Light ◽  
Antimicrobial Effect ◽  
Infrared Region ◽  
Surface Cleaning ◽  
Electromagnetic Spectrum ◽  
Implant Surface ◽  
Dental Implantation ◽  
Surgical Treatments ◽  
Further Development ◽  
Inflammatory Effect

The present article is a review of literature sources and electronic databases on the conservative treatment of mucositis and peri-implantitis. The authors analyze potentials of diode lasers, generating light in the infrared region of electromagnetic spectrum. They discuss further development of this direction and issues for the application of this type of lasers in implantology. They also discuss several parameters for the discussed laser light in dental implantology, like: antimicrobial effect, thermal effect, possible damage to implant surface, biostimulating and anti-inflammatory effect, better implant surface cleaning, accelerated osseointegration, control for apical migration and formation of stable denture attachment.

scholarly journals ANÁLISIS DE COMPONENTES PRINCIPALES DE IMÁGENES MULTIESPECTRALES EN EL ÁMBITO DEL ARTE RUPESTRE

2017 ◽  
Author(s):  
Berta Carrión-Ruiz ◽  
José Luis Lerma
Keyword(s):  
Principal Component Analysis ◽  
Near Infrared ◽  
Rock Art ◽  
Visible Region ◽  
Principal Component ◽  
Optical Filters ◽  
Infrared Region ◽  
Spectral Behaviour ◽  
Near Infrared Region ◽  
Art Analysis

This paper tackles principal component analysis (PCA) in images that include wavelengths between 380-1000 nm. Our approach is focussed on taking advantage of the potencial of ultraviolet and infrarred images, in combination with the visible ones, to improve documentation process and rock art analysis. In this way, we want to improve the discrimination between pigment and support rock, and analyse the spectral behaviour of rock art paintings in the ultraviolet and infrared regions. Three images were used, one image from the ultraviolet (UV) region, one from the visible region (VIS) and another one from the near infrared region (NIR). Optical filters coupled to the camera optics were used to take the images. These filters capture specific wavelengths excluding radiation that we are not interested in registering. Finally, PCA is applied to the acquired images. The results obtained demonstrate the PCA usefulness with imagery in this field and also it is possible to extract some conclusions about the correspondent paint pigments.http://dx.doi.org/10.4995/CIGeo2017.2017.6597

scholarly journals PHOTO-CATALYTIC TRANSPARENT HEAT MIRROR FILM TiO2/TiN/TiO2

2009 ◽  
Vol 12 (3) ◽  
pp. 24-32
Author(s):  
Tran Le ◽  
Nhuan Duy Nguyen ◽  
Cuong Hung Ngo ◽  
Chi Huu Nguyen ◽  
Tuan Tran
Keyword(s):  
Layer Thickness ◽  
Catalytic Properties ◽  
Visible Region ◽  
Infrared Region ◽  
Tio2 Films ◽  
Reactive Magnetron ◽  
Optimum Thickness ◽  
Tio2 Layer ◽  
Glass Substrates ◽  
High Reflectance

Transparenet heat mirror thin films, having high transmittance in the visible region and high reflectance in the infrared region. TiO/TiN/TiO2 films prepared D.C reactive magnetron sputtering method on glass substrates, play role as transparent heat mirror. Besides, the top TiO2 layer has both photo-catalytic and anti-reflective properties. However, st ong thickness dependence of top layer on catalytic properties is a problem need to solve. The experiment shows optimum thickness in order to have good catalytic properties is above 350 nm. This report, we found relationship among thicknesses of films through calculating and experiment. Films prepared, have both catalytic and transparent heat mirror properties with the bottom Tio, layer thickness of 40-300 nm, the middle TiN layer thickness of 16-22 nm and the top TiO2 layer of above 350 nm.

scholarly journals CHARACTERISTICS OF UHF WAVES DISTRIBUTION IN LAND AND WATER SURFACE TROPOSPHERIC WAVEGUIDE

2019 ◽  
pp. 115-121
Author(s):  
Oxana Vladimirovna Kalambatskaya ◽  
Oleg Nickolaevich Pishchin
Keyword(s):  
Communication Systems ◽  
Water Surface ◽  
Sea Water ◽  
Systems Design ◽  
Cellular Communication ◽  
Effect Of Temperature ◽  
Radio Waves ◽  
Wave Direction ◽  
Surface Atmospheric Layer ◽  
Cellular Communication Systems

The article considers examples of ultra-long propagation of UHF radio waves in mobile cellular communication systems. The phenomena are mainly observed in the Astrakhan region in the spring-summer period (May-June) and are presumably associated with sharp seasonal changes of air temperature followed by rains. The effect of temperature inversion results in changing the refraction index in the surface layer and, as a result, in changing the wave direction as the effect of superrefraction in the surface atmospheric layer. The properties of radio waves in their propagation in the land and sea-water surface waveguide are investigated. The values of the heights of land and sea-water surface tropospheric waveguides for cellular communication systems of different ranges are obtained. The features of existing of tropospheric land and sea-water surface tropospheric waveguides are described. The need to use their properties in the mobile communication systems design is stated.

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