119 research outputs found
A Study of Emission Power and Spectrum of LT-GaAs Based THz Photoconductive Antennas
AbstractEmission spectra of LT-GaAs photoconductive antennas based on epitaxial films of “low-temperature” gallium arsenide (LT-GaAs) are measured in the terahertz frequency region by the Fourier transform spectroscopy
A Study of Emission Power and Spectrum of LT-GaAs Based THz Photoconductive Antennas
AbstractEmission spectra of LT-GaAs photoconductive antennas based on epitaxial films of “low-temperature” gallium arsenide (LT-GaAs) are measured in the terahertz frequency region by the Fourier transform spectroscopy
STUDY STRUCTURE OF THREE-COMPONENT POLYMERIC MATERIAL UNDER INFLUENCE OF γ-IRRADIATION
The polymer material (РА/РЕ/Eva) with a width of 55 μm was studied. Sterilization was carried out on the unit GU–200 at doses from 3 to 18 kGy in the Research Institute of Technical Physics and Automation, Rosatom, Moscow, Russia. The structure of the polymermaterial samples was studied by IR spectroscopy before and after irradiation in a range of 400–5000 сm–1. According to the results of the analysis of the IR spectrum structure, the changes in the structure were insignificant upon irradiation at doses up to 6 kGy. Upon irradiation at doses from 9 kGy and higher, an increase in quantity of ester groups (2340 сm–1) and insignificant increase in other functional groups were observed, which can suggest a simultaneous process of intra-molecular cross-linking with the intermediatestage of cross-linking occurring with formation of vinylene groups. This causes destruction of a polymer material and radiation oxidation. These disorders can lead to changes in physico-mechanical and barrier parameters of a polymer material, which can be notably reflected in the shelf life of agricultural products
ИЗУЧЕНИЕ СТРУКТУРЫ ТРЕХКОМПОНЕНТНОГО ПОЛИМЕРНОГО МАТЕРИАЛА ПОД ВЛИЯНИЕМ γ-ОБЛУЧЕНИЯ
The polymer material (РА/РЕ/Eva) with a width of 55 μm was studied. Sterilization was carried out on the unit GU–200 at doses from 3 to 18 kGy in the Research Institute of Technical Physics and Automation, Rosatom, Moscow, Russia. The structure of the polymermaterial samples was studied by IR spectroscopy before and after irradiation in a range of 400–5000 сm–1. According to the results of the analysis of the IR spectrum structure, the changes in the structure were insignificant upon irradiation at doses up to 6 kGy. Upon irradiation at doses from 9 kGy and higher, an increase in quantity of ester groups (2340 сm–1) and insignificant increase in other functional groups were observed, which can suggest a simultaneous process of intra-molecular cross-linking with the intermediatestage of cross-linking occurring with formation of vinylene groups. This causes destruction of a polymer material and radiation oxidation. These disorders can lead to changes in physico-mechanical and barrier parameters of a polymer material, which can be notably reflected in the shelf life of agricultural products.Исследовали полимерный материал состава РА/РЕ/Eva толщиной 55 мкм. Стерилизацию проводили на установке ГУ–200 дозами от 3 до 18 кГр в Научно-исследовательском институте технической физики и автоматизации. Структуру образцов полимерного материала изучали методом ИК-спектроскопии до и после облучения в интервале 400–5000 см–1. По результатам исследования структуры ИК-спектров облучение дозами до 6 кГр изменения в структуре незначительные. При облучении дозами от 9 кГр и выше увеличивается количество сложных эфирных групп (2340 см–1), незначительное увеличение в других функциональных группах, что может говорить об одновременном процессе внутримолекулярной сшивки с промежуточной стадией сшивания протекающей с образованием виниленовых групп. Это вызывает деструкцию полимерного материала, а также радиационное окисление. Данные нарушения могут повлечь измененияфизико-механических и барьерных параметров полимерного материала, что может существенно отразиться на сроках хранения сельскохозяйственной продукции
Crustal Thickness Beneath Libya and the Origin of Partial Melt Beneath AS Sawda Volcanic Province From Receiver Function Constraints
This study investigates crustal thickness and properties within the Libyan region. Results obtained from 15 seismic stations belonging to the Libyan Center for Remote Sensing and Space Science are reported, in addition to 3 seismic stations publically available, using receiver functions. The results show crustal thicknesses ranging from 24 km to 36 km (with uncertainties ranging between ±0.10 km to ±0.90 km). More specifically, crustal thickness ranges from 32 km to 36 km in the southern portion of the Libyan territory then becomes thinner, between 24 km and 30 km, in the coastal areas of Libya and thinnest, between 24 km and 28 km, in the Sirt Basin. The observed high Vp/Vs value of 1.91 at one station located at the As Sawda Volcanic Province in central Libya indicates the presence of either partial melt or an abnormally warm area. This finding suggests that magma reservoirs beneath the Libyan territory may still be partially molten and active, thereby posing significant earthquake and volcanic risks. The hypothesis of an active magma source is further demonstrated though the presence of asthenospheric upwelling and extension of the Sirt Basin. This study provides a new calculation of unconsolidated sediment layers by using the arrival time of the P-to-S converted phases. The results show sediments thicknesses of 0.4 km to 3.7 km, with the Vp/Vs values ranging from 2.2 to 4.8. The variations in crustal thickness throughout the region are correlated with surface elevation and Bouguer gravity anomalies, which suggest that they are isostatically compensated
Geodynamical interpretation of crustal and upper mantle electrical conductivity anomalies in Sayan-Baikal province
Constraints on reflective bodies below the 8<sup>o</sup> discontinuity from reflectivity modelling
Two-dimensional seismic waveform modelling of upper mantle scattering below the 8 degree discontinuity
Evidence for layering at the Core-Mantle Boundary from core phases on Russian PNE profile Kraton
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