The history of the use of mines dates back almost two centuries. The geography of their use and the associated social harm have made them, without exaggeration, a global problem. At the same time, searches were underway for safe methods of their neutralization using various technical means. In so doing, until now, none of the existing methods provides a 100% guarantee of cleaning the territory, which determines the purpose of finding innovative methods and the possibility of combining them with existing ones. Unmanned aerial vehicles (UAVs) are becoming a real modern breakthrough in the field of intellectual achievements. Obtaining optimal results when solving a wide range of different problems, together with the development of composite materials, software, and the latest navigation equipment, make the tasks assigned to them and the expected results more and more difficult. UAVs allow people not to be in life-threatening conditions, to conduct activities beyond their physiological and psychophysiological abilities. The combination of the ability to collect spatial data during flight in various ranges of remote sensing with the possibility of carrying variants of useful equipment opens up prospects for their use in the field of demining territories. Supplementing UAV technologies with modern information systems for processing and analysis of information (expert systems, machine learning, computational intelligence, distributed artificial intelligence, neural networks, etc.), including spatial geographic information systems (GIS), opens up great prospects in the field of humanitarian demining of territories.
1 January 2015 in Progress In Electromagnetics Research Letters
A topology of high-frequency field intensity in the work area of a saddle-shaped coil for a nuclear qaudrupole resonance spectrometer was studied. With a view to determine magnetic field topology, a computational domain was created which is a model of a saddle-shaped coil physical structure. Finite element method was used to perform numerical simulation in COMSOL Multiphysics software. According to the results of calculations performed and the field maps obtained, the relative volume of coil work area was determined which makes 28.12% of its full volume. For such a volume the recommended size of samples under study is 12 × 18 × 10 mm 3 .
This paper presents the conceptual stages of the simulation and development of a modified transceiver antenna for a high-power pulsed nuclear quadrupole resonance (NQR) detector of explosives containing the 14N isotope. At a frequency of 4.645 MHz, better characteristics are obtained using a nine-turn coil shaped as half of a Fermat spiral with an outer radius of 75 mm. Using a COMSOL Multiphysics numerical parametric simulation and a materials browser, it was possible to calculate a physical system with parameters as close to reality as possible. According to the results of the experimental studies of the radio frequency (RF) energy, the proposed antenna features an increase in the working area compared to a similar antenna, the topology of the conductive coil of which has the form of an Archimedean spiral. The resulting diagrams of the distribution of the magnetic induction also indicate that the topology of the electromagnetic (EM) field does not depend on the orientation of the sample under study relative to the axis of the radial symmetry observed in square–rectangular planar antennas.
1 September 2015 in Metrology and Measurement Systems
A pulse sequence shaper for the pursuance of the research using a wide spectrum of radiospectroscopy and relaxation methods in NQR is proposed. The distinctive feature of this product is its implementation with the application of a multi-functional programmable frequency synthesizer suitable for high-speed amplitude and phase manipulations.
1 January 2019 in Telecommunications and Radio Engineering
Analysis of existing experimental methods for observing nuclear quadrupole resonance in the frequency range from ~2 to 1000 MHz showed that it is promising to develop inexpensive portable spectrometers based on new information transformation algorithms of the free induction decay signal in the transmit-receive path and spectral imaging. The development of new methods of direct pulse detection is of considerable interest to scientists due to the achievement of the sensitivity of the experiment, comparable to the sensitivity of the double resonance method while maintaining the high accuracy and informativeness of the spectra.
A low-cost digital pulsed nuclear quadrupole resonance (NQR) radio-spectrometer is proposed, all main modules of digital processing and synthesis of which on the field-programmable gate array (FPGA) are implemented. The input sensitivity of the device is of the order of 3 μV to 5 μV which allows conducting NQR studies in samples of relatively small dimensions. The application of the developed methods of NQR pulsed radio spectroscopy made it possible to increase spectral resolution, improve spectral shape and significantly reduce the time of research. In the case of studying InSe and GaSe crystals, spectra with signal-to-noise ratio (SNR) values of 41.9 dB were observed in samples with a volume of 0.1 cm3. As the results of the research have shown, the characteristics of the proposed spectrometer make it effective when used to observe free induction decay (FID) signals of a significant number of isotopes of elements with quadrupolar nuclei.