Irradiation Temperature Research Articles

Efficient selective cleavage of C−C bonds in lignin under visible light enabled by the Fe-doped mesoporous graphitic carbon nitride photocatalyst

To obtain high-valued aromatic products, it is paramount to cleave the Cα−Cβ bonds in lignin under mild conditions selectively. Nevertheless, this task remains daunting due to the formidable dissociation energies and steric hindrance associated with these bonds. Herein, a facile, efficient and cost-effective strategy for selectively breaking the Cα−Cβ bond in lignin with visible-light irradiation and room temperature is proposed, facilitated by the utilization of the ferric-doped mesoporous graphitic carbon nitride (Fe/mpg-CN) photocatalyst. Collective contributed by the reduced band gap and photoluminescence, combined with intensified visible-light absorption and enhanced photocurrent, the effectiveness in photocatalytic activity of Fe/mpg-CN is offered. Specifically, a high conversion rate (98 %) of the lignin model compound (2-phenoxy-1-phenylethanol), coupled with an excellent selectivity of 98 % in cleaving the Cα−Cβ bonds is achieved by Fe/mpg-CN. Photogenerated holes are indicated as the main active species through comprehensive mechanistic investigations. Additionally, the successful photocatalytic depolymerization of the complex dimer model compound (conversion rate ∼ 96 %) and pine kraft lignin further corroborate the satisfying photocatalytic activity and selectivity of Fe/mpg-CN. This study introduces a promising and viable strategy for the selective breaking of lignin through photocatalysis, offering significant implications for the sustainable production of valuable aromatic compounds.

Modeling and design of a separate effects irradiation test targeting fission gas release from Cr-doped UO2

Fission gas release (FGR) from nuclear fuel during operation can diminish heat transfer properties across the pellet-cladding gap and increase the fuel rod internal pressure, thereby posing a concern to fuel reliability and safety during an accident. Enlarging the fuel grain size, which has been shown to improve fission gas retention, can be achieved by doping the fuel feedstock prior to sintering. In this work, the BISON fuel performance code was used to predict FGR from undoped and chromia-doped UO2 (referred to as Cr-doped UO2) fuel specimens with different grain sizes and across various temperatures. The BISON models identified the irradiation conditions for which FGR is most significant, and a separate effects irradiation experiment in the High Flux Isotope Reactor (HFIR) was then developed targeting those conditions. The experiment leveraged the MiniFuel irradiation capability at Oak Ridge National Laboratory and consisted of 12 fuel specimens of varying grain size and Cr content. A coupling scheme between BISON FGR results and the ANSYS finite element thermal model used for experiment design was formulated to predict cumulative FGR from each fuel specimen based on expected irradiation temperature histories. The fuel samples were fabricated and characterized as a part of this work, and the fuel compositions modeled in BISON were representative of the specimens used in the experiment. This combined modeling and experimental effort aims to study the effect of fuel grain size and Cr content on FGR and to provide simulated BISON FGR results that can be used for future model validation activities.

Design and implementation of Type-3 intuitionistic fuzzy logic MPPT controller for PV solar system: Comparative study

The performance of a photovoltaic (PV) solar system is affected by partial shading conditions (PSC) and environmental conditions, such as solar irradiance and ambient temperature, which vary throughout the day. This results in variations in the maximum power point (MPP) on the solar PV output characteristic curve. Therefore, various classical MPP tracking (MPPT) techniques have been used to track the MPP and extract maximum power from PV systems. However, these techniques have drawbacks such as lower stability, increased oscillation around the steady state, and slower convergence to the MPP. To overcome this problem, the newly proposed interval Type-3 intuitionistic fuzzy logic (T3IFL) controller has been proposed. The T3IFL MPPT controller combines the uncertainty of Type-3 fuzzy logic (T3FL) controller with intuitionistic concepts. The T3IFL controller is more accurate and offers faster convergence to the MPP under changing climatic and steady-state conditions than classical techniques and T3FL controller. The T3IFL algorithm provides better performance with excellent MPP tracking by controlling the duty cycle of the DC-DC buck converter. Four cases studied were investigated: uniform radiation conditions, a step change in solar radiation with constant temperature, replacing the battery load with the ohmic load with constant radiation and temperature, and partial shading conditions. Experimental validation of the T3IFL was performed on a DC-DC buck converter using real-time hardware-in-the-loop (HIL). Finally, the simulation and experimental results with comparative studies verified the accuracy of the proposed method in tracking the desired value and disturbance/uncertainty attenuation with better response.

Deuterium retention in displacement-damaged tungsten-rhenium alloys: Influence of rhenium concentration and irradiation temperature

Tungsten (W) samples containing 0, 1, 3, and 5 at.% rhenium (Re) were irradiated by 20 MeV W ions to 0.5 dpa at 290 K and to 0.3 dpa at 1350 K. An additional set of samples was irradiated to 0.5 dpa at 290 K and then annealed at 1350 K. The irradiated samples were exposed to a deuterium (D) plasma at 370 K. D concentration profiles in the samples were measured using D(He3,p)α nuclear reaction analysis. The D binding states in the defects were analysed using thermal desorption spectroscopy (TDS). In the case of irradiation at 290 K, the trapped D concentration monotonically increases with increasing Re concentration: in W-5%Re it is 17% higher than in pure W. On the contrary, for irradiation at 1350 K the trapped D concentration monotonically decreases with increasing Re concentration: in W-5%Re it is 50 times smaller than in pure W. In the case of annealing at 1350 K of the samples irradiated at 290 K, the Re presence yields only up to three times reduction of trapped D concentration compared with pure W. TDS shows that the nature of D trapping sites is different for the irradiations at 290 K and 1350 K. We attribute the reduced D trapping in W-Re alloys irradiated at 1350 K to the reduction of cavity growth caused by the presence of Re.

A superhydrophilic/air superoleophobic sponge based on layer by layer deposition for high-performance continuous adsorption water in oil

At present, there are few studies on the removal of water from oil, but water in fuel can cause machine malfunctions and even safety accidents, which cannot be ignored. In this study, an oil-resistant superhydrophilic/air superoleophobic sponge (SS-MS) was designed to selectively absorb water from oil. Through layer by layer deposition, polyphenols, particles, and fluorinated surfactants were assembled on the sponge, finally achieving the effect of super hydrophilic and super oil phobic in the air. The contact angle of the modified sponge SS-MS on diesel oil can reach 153°, and the absorption efficiency of water in diesel oil can reach more than 99 %. Moreover, a continuous selective absorption device for water in oil was constructed, the SS-MS sponge can still achieve a water absorption efficiency of 98 % after ten cycles. Importantly, the SS-MS has excellent mechanical and chemical stability under 80 % strain, different pH, UV irradiation times and temperatures. In addition, the materials used in this study are all green and low-pollution substances, and melamine sponge has the advantages of low price, light weight, good elasticity and high porosity. In summary, SS-MS offers a new approach to remove water from fuel and has the potential for large-scale applications.

Phase stability and microstructure of neutron-irradiated substoichiometric yttrium dihydrides

The impact of the neutron-displacement damage on phase stability and microstructure of substoichiometric yttrium dihydrides (YHx, x <2) were investigated to assess their use as solid moderator in high-temperature nuclear reactors. YHx specimens were, thus, subjected to neutron irradiations in the range of 0.1–2 displacements per yttrium atom (dpa-Y) in the temperature range of 536–878°C at the Oak Ridge National Laboratory's (ORNL's) High Flux Isotope Reactor (HFIR). YHx specimens were initially prepared at stoichiometry (H/Y) ratios of 1.69 and 1.83. HFIR-irradiated specimens were characterized by variety of techniques to investigate H retention characteristics including dimensional analysis, optical microscopy, scanning electron microscopy electron back scatter diffraction (EBSD), transmission electron microscopy, thermal desorption spectroscopy (TDS), and high-energy x-ray diffraction (HE-XRD) characterizations. Overall, YHx exhibited notable structural and phase stability under short-term neutron-irradiation, except for the samples with significant silicon carbide (SiC) interaction at high doses and temperatures. Basic dimensional and mass measurements were misleading for accurate assessment of H retention, as confirmed by EBSD phase maps, XRD line profiles, and TDS signals. Thus, it was discussed that a robust H retention metric is needed to assess irradiated hydrides. Nanoscale cavities were observed as a result of the neutron irradiation in all samples. Although no clear impact of dose and irradiation temperature was determined, the initial H/Y ratio had an impact on the cavity number density where low H/Y specimens had high-resistance to cavity formation. The Y-vacancy cluster formation at the collision stage of the displacement cascade and their stabilization by H were considered to be the likely underlying mechanisms for the observed cavity microstructure.

Energy analysis of a direct expansion heat pump assisted by a thermal photovoltaic panel for hot water production in several regions of Brazil

This study focused on evaluating the energy performance and economic viability of a direct expansion photovoltaic-Thermal Heat Pump (PV-T/HP) system for residential heating applications in various regions of Brazil. A detailed mathematical model was implemented to compare the PV-T/HP system with other solar heating technologies, as photovoltaic with solar evacuated tubes collector (PV+TSC) and photovoltaic with electrical heat water (PV+EHW), analyzing key metrics such as electrical efficiency, thermal efficiency, and levelized cost of heat (LCOH). The study revealed variations ranging from 7.5 to 2.5 in the Coefficient of Performance (COP) of the heat pump under different solar irradiation and ambient temperature conditions, emphasizing the necessity for future optimization to enhance the system performance. Results indicated that cities with the lower ambient temperature such as Belo Horizonte and Porto Alegre exhibited favorable conditions for the PV-T/HP system, leading to increased energy generation and positive net electricity production. The study highlighted the need for tailored strategies to control system operations, limit compressor consumption, and improve overall efficiency. These findings contribute to the understanding of PV-T/HP systems in residential heating applications, showcasing their potential for sustainable energy solutions in Brazil.

Challenges in developing materials for microreactors: A case-study of yttrium dihydride in extreme conditions

The development of microreactor technology presents an efficient solution for providing portable electricity, catering to both human space exploration needs within our solar system and supplying power to remote Earth-bound areas. The miniaturization of nuclear reactors poses immediate new challenges for materials science with respect to the capability for controlling nuclear reactions via thermalization of highly-energetic neutrons. In a microreactor, neutron moderation takes place in compact geometries, thus new moderator materials are required to exhibit high moderating power per unit of volume. This challenge is currently being addressed through the development of transition metal hydrides, known for their strong nuclear moderation capability but to date, research on their irradiation response is limited, specifically regarding phase stability, hydrogen in-lattice retention, and their dependence on irradiation temperature and dose. Herein, we present a detailed investigation on the response of yttrium dihydride (YH2) to heavy ion irradiation. The experiments indicate that YH2 is stable up to an irradiation dose of 2 dpa and below 800°C, identified herein as a critical temperature for YH2. Our study detected the nucleation and growth of voids as a function of the irradiation temperature. They were the predominant type of radiation damage present in the microstructure of YH2 that was distinguishable from pre-existing defects in the pristine YH2 samples. Below the critical temperature, no phase transformation (degassing/dehydriding) nor amorphization occurred. Experimental results with concomitant density functional theory calculations allowed us to elaborate and propose new strategies to enhance the metal hydride performance in extreme environments.

A study on He ion irradiation damage in (Ti0.25Zr0.25Nb0.25Ta0.25)C high-entropy carbide ceramics from room temperature to 700 °C

High-entropy carbide ceramics (Ti0.25Zr0.25Nb0.25Ta0.25)C with a single-phase rock-salt structure were prepared by hot-pressed sintering. These ceramics were irradiated with 500 keV He2+ ions to fluences of 5 × 1016 ions·cm−2 and 1 × 1017 ions·cm−2 at room temperature to 700 °C. The investigation into irradiation-induced lattice swelling was conducted using grazing incident X-ray diffraction, while microstructure evolution was characterized through transmission electron microscopy. Lattice expansion induced by the He ion irradiation was identified, which highly depends on the irradiation temperature and fluence. Notably, the lattice expansion diminishes with rising irradiation temperature primarily as a result of the dynamic annealing effect. Nano-sized He bubbles, with an average diameter of less than 1 nm were uniformly dispersed within the grain interior. Notably, He bubble nucleation does not exhibit a preference for grain boundaries at 700 °C irradiation. Following He ion irradiation at 350 °C and 700 °C, dislocation loops of 1/3<111> and 1/2<110> with sizes in the ranges of several nanometers were observed. The present study provides insights into high-entropy carbide ceramics with potential applications in the field of nuclear energy.

Temporal variability in transmission spectra of H2-dominated exoplanets: The influence of thermal evolution and stellar irradiation on atmospheric composition

Planets and their host stars undergo evolutionary changes over time, resulting in variations in internal temperature and incoming radiation, which significantly impact the temperature structure and composition of their atmospheres. These evolving conditions give rise to distinctive features in planetary spectra that are observable only during specific stages of planetary evolution. We aim to understand how the composition of planets with H2-dominated atmospheres changes over longer timescales due to their thermal evolution. We also investigate time-dependent features in the transmission spectra. These features could provide insights in both the formation and evolution of these gaseous planets, as well as the timescales of these changes, enabling us to study the potential variability of exoplanets over time. We evolve a ∼0.04 MJup and ∼0.45 MJup planet around a 1.0 M⊙ and 1.3 M⊙ star respectively for 109.5 years. In both systems, the planets are considered at semi-major axes of 0.1 AU and 1.0 AU. The star-planet systems are evolved by making use of Modules for Experiments in Stellar Astrophysics (MESA). The temperature–pressure profiles are obtained at selected time-steps using an analytical approximation based on the internal and irradiation temperature of the planet at each time step. We then use VULCAN, a photochemical kinetics code, to see how the composition changes with time in the atmosphere due to the thermal evolution of the planets. By making use of the radiative transfer code petitRADTrans, we also simulate the evolution of the transmission spectra of the planets to find potential time-dependent spectral features. Our findings show a prominent change in the CO2 feature at ∼4.3μm. For the 0.45 MJup case, this feature is visible in the pre-main-sequence phase of the host star, regardless of orbital distance from the host star. In the case of the ∼0.04 MJup planet, this CO2 feature is visible until t ≤ 106 years, and then it reappears after t ≥ 108 years when the planet is 0.1 AU away the host star. The CH4 features at ∼3.3μm and ∼7.5μm are only time-dependent when the planet is located at 0.1 AU from the host star and experiences high irradiation since the high temperature at early stages favoured CO2 over CH4. When the planet is 1.0 AU away from its host star, the CH4 features are always visible regardless of the mass and hence internal temperature of the planet.

Study of irradiation temperature effect on radiation-induced polymorphic transformation mechanisms in ZrO2 ceramics

The influence of high-dose exposure to heavy Xe23+ ions on the alteration in optical and structural properties, alongside the polymorphic transformation degree in polycrystalline ZrO2 ceramics is considered in the paper. The focus on such studies is primarily due to the possibility of obtaining new data on the mechanisms of radiation-induced damage associated with exposure to heavy ions comparable to fission fragments of nuclear fuel, alongside the comparison of the observed changes in the damaged layer properties with the polymorphic transformation processes characteristic of ZrO2 ceramics. Analysis of the obtained data on alterations in the optical and structural features of ceramics contingent upon irradiation conditions revealed that, the irradiation temperature leads to less pronounced structural degradation caused by deformation distortions of OI-Zr-OI, Zr-OII, Zr-OI/OII and Zr-OI bonds, as well as the accumulation of oxygen vacancies in the damaged layer. At the same time, using a set of research methods, it was determined that at irradiation temperatures above 700 K the processes of polymorphic transformations t – ZrO2→ c – ZrO2 caused by radiation and deformation effects are less pronounced, which results in the formation of inclusions in the form of t – ZrO2.

Irradiation response of microstructure and mechanical properties of NbMoVCr multi-principal element alloy coatings

In this study, NbMoVCr multi-principal element alloy (MPEA) coatings with near-equal atomic ratios were deposited onto the ferritic/martensitic (F/M) steel substrate by magnetron sputtering and then irradiated using 6 MeV Au2+ at room temperature (RT) and 550 °C, respectively. The results demonstrate that the NbMoVCr coatings have excellent irradiation resistance in terms of phase stability. RT-irradiation introduces both interstitial- and vacancy-type dislocation loops, and the dislocation loop density increases with the increase of irradiation damage dose. Meanwhile, RT-irradiation could also induce grain growth of the coating. However, under high-temperature irradiation, more recombination and annihilation of irradiation-induced defects, and recrystallization occur in the coating. In addition, irradiation also promotes the desegregation of V and Cr elements at the grain boundaries and enhances the uniformity of the distribution of coating elements. Irradiation softening and hardening in NbMoVCr coatings are also found to depend strongly on both irradiation damage dose and irradiation temperature. The creep deformation mechanism of the coating is dominated by diffusion; thus, the irradiation-enhanced diffusion reduces the creep resistance of the coating.

Design of a Weathering Chamber for UV Aging of Microplastics in the Mediterranean Region.

Microplastics are an ever-growing concern in the environment. Their degradation may lead to greater absorption of toxic pollutants, which may ultimately pose a threat to human health. In the pursuit of understanding microplastics' fate, behavior, and toxicity, there is a vital need to understand their aging and weathering. For this, multiple weathering setup designs were put forward. However, standardization of a weathering setup presents a significant challenge to the field due to apparatus costs, wide range of experimental parameters, or the lack of detailed reporting. This work seeks to make much-needed data gathering more accessible by constructing a low-cost weathering chamber that simulates Mediterranean shore conditions. The weathering chamber incorporates UV irradiation, mechanical abrasion, and elevated temperatures. After extensive preliminary testing, the chamber was able to achieve the desired outcome along with UV-A irradiance values, which were similar to those in the Mediterranean.

Biochemical changes due to photothermal acclimation of Oedogonium and associated implications for photosynthetic growth and biomass utilisation

Freshwater filamentous algae have potential for wastewater bioremediation and bioproduct generation. This study investigated the separate and combined effects of growth irradiance regime (300 ± 25 μmol.m−2.s−1 with 13:11 dark:light cycle or 775 ± 25 μmol.m−2.s−1 with 8:16 dark:light cycle) and temperature (15 ± 1 or 25 ± 1 °C) during acclimation on the adaptive biochemistry and photosynthetic activity of Oedogonium with the higher and lower levels representing average outdoor conditions in summer and winter in Melbourne, Australia, respectively. Photoprotective pigments were upregulated in response to either high irradiance regime or temperature, while the chlorophyll content was also reduced when both stressors were combined. The upregulation of protective adaptations slightly lowered photosynthetic efficiency, which was more dramatically impaired by the reduced chlorophyll at high temperature and irradiance. The polar lipid content increased from ~10% to ~30% of total lipid content, the protein content decreased by ~10% and the starch content increased by 30% in response to higher irradiance and temperature, with implications for biomass utilisation. These changes in biochemical composition due to long-term acclimation suggests the potential for compositional stratification in stable floating filamentous algae mats due to the presence of self-shading. Further, the shading created by the upper layers in the mat can be expected to provide further protection to the biomass at the lower levels against photooxidative stress. The results reveal the impact of variations on seasonal growth conditions and filamentous mat depth on the composition and productivity of the algae.

Series partial power converter with half bridge LLC series resonant converter for PV application

Abstract This study proposes a series partial power converter with a half-bridge LLC series resonant converter for photovoltaic (PV) applications. The main advantage of the implementation of a partial power converter with LLC series resonant converter is zero voltage switching (ZVS) operation of primary side enables the converter to work at a higher switching frequency. The partial power topology used in the proposed converter enables low power rating switches in the primary, which in other terms reduces the primary current. The proposed converter achieves excellent efficiency due to its ZVS and partial power operating capabilities. The valuation of the proposed converter is done in MATLAB Simulink with a 300 W PV module, which is made to operate in varying irradiance and module temperature of 25 °C. The operational waveforms and the power outputs obtained when the proposed converter is implemented by using perturbation and observation (P&amp;O) maximum power point tracking (MPPT) control algorithm are discussed in this paper.

A simplified approach to modeling temperature dynamics in photovoltaic systems – Validation, case studies, and parametric analysis

This paper presents a simplified theoretical model for analyzing the temperature dynamics of photovoltaic (PV) modules. The model is built on an energy balance approach, considering solar irradiation as the primary energy input. It accounts for the conversion of solar power into electricity and the storage of thermal energy within the PV module, which subsequently increases the PV temperature leading to decay in its electrical efficiency. Heat loss from the top and bottom surfaces of the module, with variations for cooling techniques, is also included. The model is validated against three different experimental studies, demonstrating good agreement with the experimental temperature variations, with a maximum discrepancy ranging from 4 % to 16 %. This simplified model is then applied to two case studies: one representing typical daytime conditions and another simulating cold weather events. By comparing the PV temperature dynamics between the model and the experimental data, it is shown that the model accurately captures the dynamic response of the PV temperatures to changes in solar irradiation and ambient temperatures. Moreover, a parametric analysis is conducted to investigate the effects of key parameters on PV temperature and efficiency. Higher cooling rates from the bottom surface significantly boost electric power output, aligning closely with solar irradiance variations. Enhanced upper surface cooling, through increased convection, reduces PV temperature and thereby improves electric efficiency and power production. The PV temperature increases quasi-linearly with ambient temperature, especially at lower wind speeds, and decreases with higher wind speeds, eventually stabilizing at high values. Additionally, both ambient temperature and solar irradiance contribute to rising PV temperatures, with ambient temperature having a slightly greater effect. These findings underscore the critical role of cooling techniques in optimizing PV performance amidst varying environmental conditions.

Antireflective Superhydrophobic and Robust Coating Based on Chitin Nanofibers and Methylsilanized Silica for Outdoor Applications.

Antireflective coatings with superhydrophobicity have many outdoor applications, such as solar photovoltaic panels and windshields. In this study, we fabricated an omnidirectional antireflective and superhydrophobic coating with good mechanical robustness and environmental durability via the spin coating technique. The coating consisted of a layer of phytic acid (PA)/polyacrylamide (PAM)/calcium ions (Ca2+) (referred to as Binder), an antireflective layer composed of chitin nanofibers (ChNFs), and a hydrophobic layer composed of methylsilanized silica (referred to as Mosil). The transmittance of a glass slide with the Binder/ChNFs/Mosil coating had a 5.2% gain at a wavelength of 550 nm, and the antireflective coating showed a water contact angle as high as 160° and a water sliding angle of 8°. The mechanical robustness and environmental durability of the coating, including resistance to peeling, dynamic impact, chemical erosion, ultraviolet (UV) irradiation, and high temperature, were evaluated. The coating retained excellent antireflective capacity and self-cleaning performance in the harsh conditions. The increase in voltage per unit area of a solar panel with a Binder/ChNFs/Mosil coating reached 0.4 mV/cm2 compared to the solar panel exposed to sunlight with an intensity of 54.3 × 103 lx. This work not only demonstrates that ChNFs can be used as raw materials to fabricate antireflective superhydrophobic coatings for outdoor applications but also provides a feasible and efficient approach to do so.

Efficient and selective cleavage of lignin C–C bonds under visible light facilitated by the Zn(II)-doped mesoporous graphitic carbon nitride photocatalyst

Despite the promise of photocatalysis for extracting aromatic compounds from renewable lignin feedstocks, the selective cleavage of Cα–Cβ bonds in lignin under mild conditions poses a persistent challenge, primarily due to their elevated dissociation energies and steric hindrance. Herein, an efficient photocatalytic strategy for selectively breaking the Cα–Cβ bonds of lignin with visible-light irradiation and room temperature is proposed, facilitated by the Zn(II)-doped porous graphitic carbon nitride (Zn/CN) photocatalyst. Reduced energy band gap and photoluminescence, along with intensified visible-light absorption and enhanced photocurrent of Zn/CN, contribute to its efficacy in photocatalytic activity. Consequently, the lignin model compound (2-phenoxy-1-phenylethanol) achieves a conversion rate of 99 %, demonstrating a notable selectivity of 97 % in specifically breaking the Cα–Cβ bonds. Mechanistic investigations identify that photogenerated holes play a pivotal role during the photocatalytic conversion. Additionally, the activity and selectivity of Zn/CN photocatalyst are further confirmed by the successful photocatalytic conversion of pine kraft lignin, yielding high-value chemicals such as benzoic acid and vanillin. This research proposes an economical, efficient, and facile method for utilizing renewable lignin feedstocks under photocatalysis, thus advancing the production of high-value aromatic compounds.

Identification of temperature and diffusion effects during helium swelling of the surface layer of a TiTaNbV alloy

The article presents the comprehensive analysis results of the connection between structural changes caused by the effects of deformation swelling and softening effects during high-dose irradiation with He2+ ions, alongside determines the kinetics of changes in structural and strength parameters contingent upon irradiation conditions (in the case of irradiation temperature variations). The interest in such studies is due to the need to study the influence of temperature factors on the diffusion mechanisms of implanted He2+ into the damaged layer of a high-entropy TiTaNbV alloy in the case of high-dose irradiation. At the same time, the study of such mechanisms makes it possible to determine not only the radiation resistance of TiTaNbV alloys, but also to expand the general understanding of the influence of the structural features of high-entropy alloys associated with deformation distortion of the crystal structure, which prevents diffusion and migration mechanisms of defect propagation in the damaged layer. During determination of changes in strength properties depending on irradiation conditions, it was found that irradiation temperature growth leads to both a rise in the degree of softening under high-dose irradiation and an increase in the thickness of the softened layer under high-dose irradiation. These changes indicate that at high temperatures, the diffusion of implanted ions is not restrained by structural distortions, which results in their migration to a greater depth exceeding the ion travel depth, which should be considered when designing the use of these alloys in the case of their operation in extreme conditions.

Kinetics of Carrier Lifetime Degradation in High‐Temperature 1 MeV Electron‐Irradiated Cz n‐Si Associated with the Formation of Divacancy‐Oxygen Defects

Kinetics of degradation of the nonequilibrium charge carrier lifetime (τ) in Czochralski‐grown (Cz) n‐Si irradiated with 1 MeV electrons at different temperatures in the range from 20 to 285 °C are experimentally and theoretically investigated. It is established that changes in τ are qualitatively and quantitatively determined by the temperature of electron irradiation. Analysis of experimental data using the Shockley‐Read‐Hall (SRH) theory shows that the formation of recombinationally active divacancy‐oxygen (V2O) and vacancy‐oxygen (VO) complexes is the main mechanism of τ degradation in this experiment.