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

Investigation principles of creation of nanosecond laser driver with operating frequency up to 10 kHz

Abstract The aim of the work is to create a miniature pulse optical lidar on an infrared laser diode by means of highly effective avalanche switching in bipolar silicon transistors. Confident operation of the optical switch board at a frequency of 10 kHz with a dynamic charging circuit has been achieved. The ways of increasing the radiation power, increasing the repetition rate of pulses (necessary to improve the accuracy of the lidar) are considered

Miniature high-power nanosecond laser diode transmitters utilizing simplest avalanche drivers

Abstract The-state-of-the-art in long-distance near-infrared optical radars is the use of laser-diode-based miniature pulsed transmitters producing optical pulses of 3–10 ns in duration and peak power typically below 40W. The duration of the transmitted optical pulses becomes a bottleneck in the task of improving the radar ranging precision, particularly due to the progress made in developing single photon avalanche detectors (SPADs). The speed of miniature high-current drivers is limited by the speed of the semiconductor switch, either a gallium nitride (GaN) field-effect transistor, the most popular alternative nowadays, or a silicon avalanche bipolar junction transistor (ABJT), which was traditional in the past. Recent progress in the physical understanding of peculiar 3-D transients promises further enhancement in speed and efficiency of properly modified ABJTs, but that is not the only factor limiting the transmitter speed. We show here that a low-inductance miniature transmitter assembly containing only a specially developed capacitor, a more advanced transistor chip than that used in commercial ABJTs and a laser diode has allowed peak power from 40 to 180 W to be reached in optical pulses of 1–2 ns in duration without after-pulsing relaxation oscillations. This finding is of interest for compact low-cost, long-distance decimetre-precision lidars, particularly for automotive applications