scholarly journals Characterization of Back-Scattering and Multipath in a Suburban Area after the Calibration of an X-Band Commercial Radar

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 463 ◽  
Author(s):  
Gaspare Galati ◽  
Gabriele Pavan ◽  
Christoph Wasserzier
Keyword(s):  
Radar Detection ◽  
Related Field ◽  
Online Evaluation ◽  
Area Of Interest ◽  
X Band ◽  
Back Scattering ◽  
Precise Quantification ◽  
Great Relevance ◽  
Detection Capabilities

The increasing interest in the radar detection of low-elevation and small-size targets in complicated ground environments (such as urban, suburban, and mixed country areas) calls for a precise quantification of the radar detection capabilities in those areas. Hence, a set of procedures is devised and tested, both theoretically and experimentally, using a commercial X-band radar, to (i) calibrate the radar sensor (with an online evaluation of its losses) using standard scatterers, (ii) measure the multipath effect and compensate for it, and (iii) create “true radar cross section” maps of the area of interest for both point and distributed clutter. The above methods and the related field results are aimed at future qualification procedures and practical usage of small, cheap, and easily moveable radars for the detection of low-observable air targets, such as unmanned air vehicles/systems (UAV/UAS), in difficult ground areas. A significant set of experimental results as discussed in the paper confirms the great relevance of multipath in ground-based radar detection, with the need for correcting measures.

Assessing the Power of Electron Back Scattering Diffraction Characterization of Deformed F-138 Steel from the View Point of Crystal Diffraction

2014 ◽  
Vol 51 (9) ◽  
pp. 634-655
Author(s):  
R. E. Bolmaro ◽  
M. C. Avalos ◽  
N. S. De Vincentis ◽  
A. M. Kliauga ◽  
H.-G. Brokmeier
Keyword(s):  
View Point ◽  
Back Scattering

scholarly journals Structure from Motion Multisource Application for Landslide Characterization and Monitoring: The Champlas du Col Case Study, Sestriere, North-Western Italy

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2364 ◽  
Author(s):  
Martina Cignetti ◽  
Danilo Godone ◽  
Aleksandra Wrzesniak ◽  
Daniele Giordan
Keyword(s):  
Structure From Motion ◽  
Winter Season ◽  
Cost Effective ◽  
Point Clouds ◽  
Slope Instability ◽  
Ski Resorts ◽  
Area Of Interest ◽  
3D Point Clouds ◽  
North Western

Structure from Motion (SfM) is a powerful tool to provide 3D point clouds from a sequence of images taken from different remote sensing technologies. The use of this approach for processing images captured from both Remotely Piloted Aerial Vehicles (RPAS), historical aerial photograms, and smartphones, constitutes a valuable solution for the identification and characterization of active landslides. We applied SfM to process all the acquired and available images for the study of the Champlas du Col landslide, a complex slope instability reactivated in spring 2018 in the Piemonte Region (north-western Italy). This last reactivation of the slide, principally due to snow melting at the end of the winter season, interrupted the main road used to reach Sestriere, one of the most famous ski resorts in north-western Italy. We tested how SfM can be applied to process high-resolution multisource datasets by processing: (i) historical aerial photograms collected from five diverse regional flights, (ii) RGB and multi-spectral images acquired by two RPAS, taken in different moments, and (iii) terrestrial sequences of the most representative kinematic elements due to the evolution of the landslide. In addition, we obtained an overall framework of the historical development of the area of interest, and distinguished several generations of landslides. Moreover, an in-depth geomorphological characterization of the Champlas du Col landslide reactivation was done, by testing a cost-effective and rapid methodology based on SfM principles, which is easily repeatable to characterize and investigate active landslides.

Preparation and Characterization of Zn-Se Bilayer Structure

2007 ◽  
Vol 31 ◽  
pp. 153-157
Author(s):  
M. Singh ◽  
J.S. Arora ◽  
Kamlendra Awasthi ◽  
R. Nathawat ◽  
Y.K. Vijay
Keyword(s):  
Grain Size ◽  
Annealing Temperature ◽  
Hexagonal Structure ◽  
Scattering Data ◽  
Bilayer Structure ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
Rutherford Back Scattering ◽  
Back Scattering

The Zn-Se bilayer structure prepared using thermal evaporation method at pressure 10-5 Torr. These films annealed in the vacuum for two hours on different constant temperatures. The optical band gap was found to be varying with annealing temperature due to removal of defects and increase in grain size. It was also observed by the X-ray diffraction pattern the grain size of the film increase with annealing temperature. The lattice constant of hexagonal structure of these films is found to be a =b=4.42Å and c=5.68Å. The dominant peaks to be at 23.2°,28° and 43.9° having values (100), (002) and (111) respectively. The Rutherford back scattering data of these films confirmed the mixing of elements with time.

Perfect metamaterial absorbers with polarization angle independency in X-band waveguide

2016 ◽  
Vol 30 (11) ◽  
pp. 1650186 ◽  
Author(s):  
Cumali Sabah
Keyword(s):  
Wireless Communication ◽  
Frequency Region ◽  
Polarization Angle ◽  
Perfect Absorption ◽  
Band Frequency ◽  
X Band ◽  
Resonance Frequencies ◽  
Metamaterial Absorbers ◽  
Space Boundary

The design and characterization of perfect metamaterial absorbers (MAs) based on simple configurations including square- and triangle-shapes, which operate in X-band frequency region are numerically and experimentally investigated. The proposed MAs provide perfect absorption with the polarization angle independency. In X-band waveguide, the absorption rates are 99.69% and 99.97% at the resonance frequencies of 10.57 GHz and 10.93 GHz for the square- and triangle-shaped MAs, respectively. In addition, the same configurations are numerically tested under free space boundary conditions to compare and discuss the obtained results. The suggested MAs enable myriad potential application areas for security and stealth technologies in X-band including wireless communication.

scholarly journals A photochemical determination of luminescence efficiency of upconverting nanoparticles

2019 ◽  
Vol 15 ◽  
pp. 2671-2677 ◽  
Author(s):  
Baptiste Amouroux ◽  
Clément Roux ◽  
Jean-Claude Micheau ◽  
Fabienne Gauffre ◽  
Christophe Coudret
Keyword(s):  
Near Infrared ◽  
Green Emission ◽  
Accurate Estimation ◽  
Luminescent Probes ◽  
Luminescence Efficiency ◽  
Visible Spectra ◽  
Precise Quantification ◽  
Infrared Excitation

Upconverting nanoparticles are a rising class of non-linear luminescent probes burgeoning since the beginning of the 2000’s, especially for their attractiveness in theranostics. However, the precise quantification of the light delivered remains a hot problem in order to estimate their impact on the biological medium. Sophisticated photophysical measurements under near infrared excitation have been developed only by few teams. Here, we present the first attempt towards a simple and cheap photochemical approach consisting of an actinometric characterization of the green emission of NaYF4:Yb,Er nanoparticles. Using the recently calibrated actinometer 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene operating in the green region of the visible spectra, we propose a simple photochemical experiment to get an accurate estimation of the efficiency of these green-emitting “nanolamps”. The agreement of the collected data with the previous published results validates this approach.

Characterization of Barium M-Hexaferrite with Doping Zn and Mn for Microwaves Absorbent

2019 ◽  
Vol 966 ◽  
pp. 282-289 ◽  
Author(s):  
Susilawati ◽  
Aris Doyan ◽  
Muhammad Taufik ◽  
Wahyudi ◽  
Eryn Ryantin Gunawan ◽  
...  
Keyword(s):  
Calcination Temperature ◽  
Ion Concentration ◽  
Magnetic Minerals ◽  
Natural Sand ◽  
Band Frequency ◽  
Absorbent Material ◽  
Electrical And Magnetic Properties ◽  
Magnetic Remanence ◽  
X Band

The research was conducted to examine the content of Fe and other metal in natural sand of beach Ampenan, Mataram, Indonesia which is expected to be used as microwave absorbent material. Characterizations of the electrical and magnetic properties Barium M-Hexaferrite (BaM) with Zn-Mn doping (BaFe12-2xZnxMnxO19) are biosynthesized. Research carried out among others tested the metal content of Fe and other metals, synthesize BaFe12-2xZnxMnxO19. The samples were characterized using Vibrating Sample Magnetometer (VSM) and Network Vector Analyzer (VNA) for the test properties of electricity and magnetism, as well as the absorption of microwaves. The results from the AAS (Atomic Absorption Spectroscopy) testing showed that each gram of magnetic minerals in the natural sand containing 16.27 mg Fe, which states that the majority of metal components content is 69.80% Fe metal with the Magnetite and Hematite phases. The result from VSM showed that the coercivity value decreased when doping ion concentration and calcination temperature increased (0.16 Tesla at 600°C for x = 0.0 and 0.09 Tesla at 800°C for x = 1.0). Value of magnetic saturation and the magnetic remanence decreased with increasing ion concentration (Ms= 4.94 emu/g at x = 0.0 decreased to 0.31 emu/g at x = 1.0) and Mr = 3.43 emu/g for x = 0.0 decreased to 0.06 emu/g at x=1.0. These indicates that the sample has been soft magnetic. The result from VNA showed that the electrical conductivity values measured in the range 8.0-15.0 GHz indicate that the sample is a semiconductor (1.62×10-2 S/cm). The result from VNA showed that the microwave absorption properties increased at higher concentration of doping ions and the calcination temperature would increase the value of Reflection Loss (RL). Maximum RL value of the sample is -14.37 dB at 15 GHz and the absorption coefficient of 96.34%. These results indicate that the BaFe10.8Zn0.6Mn0.6O19 sample can be applied as a microwave absorbent material on X-band to Ku- band frequency. Keyword: Characterization, Barium M-Hexaferrite, doping, microwave, absorbent.

Microwave characterization of Co–Ti substituted barium hexagonal ferrites in X- band

2016 ◽  
Vol 405 ◽  
pp. 17-21 ◽  
Author(s):  
Sukhleen Bindra Narang ◽  
Pawandeep Kaur ◽  
Shalini Bahel ◽  
Charanjeet Singh
Keyword(s):  
Hexagonal Ferrites ◽  
Microwave Characterization ◽  
X Band
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