Effect Of Electron Beam Irradiation Research Articles

Atomic Insight into Thermolysis‐Driven Growth of 2D MoS2

AbstractUnderstanding and controlling the transformations of transition metal dichalcogenides (TMDs) from amorphous precursors into two‐dimensional (2D) materials is important for guiding synthesis, directing fabrication, and tailoring functional properties. Here, the combined effects of thermal energy and electron beam irradiation are explored on the structural evolution of 2D MoS2 flakes through the thermal decomposition of a (NH4)2MoS4 precursor inside an ultrahigh vacuum (10−9 Torr) scanning transmission electron microscope (STEM). The influence of reaction temperature, growth substrate, and the initial precursor morphology on the resulting 2D MoS2 flake morphology, edge structures, and point defects are explored. Although thermal decomposition occurs extremely fast at elevated temperatures and is difficult to capture using current STEM techniques, electron beam irradiation can induce local transformations at lower temperatures, enabling direct observation and interpretation of critical growth steps including oriented attachment and transition from single‐ to multilayer structures at atomic resolution. An increase in the number of layers of the MoS2 flakes from island growth is investigated using electron beam irradiation. These findings provide insight into the growth mechanisms and factors that control the synthesis of few‐layer MoS2 flakes through thermolysis and toward the prospect of atomically precise control and growth of 2D TMDs.

Effect of coating adhesion and degradation on tin whisker mitigation of polyurethane-based conformal coatings

Tin whisker growth, which may lead to short circuits and current leakage, is a serious issue in electronics components. Polyurethane-based conformal coatings have been seen as an effective candidate to mitigate the tin whisker growth. To better understand the effect of such coatings, this study exposed the tin-plated copper coupons coated with i) moisture cured polyurethane (PU) and ii) dual UV/moisture cured polyurethane acrylate (PUA), for long-term (up to 5000 h) high-temperature and high-humidity (HTHH) storage (85 °C and 85%RH, respectively). After HTHH storage, microstructural developments in the tin layer, coating degradation, tin surface reaction, and coating adhesion to tin surface were analyzed to compare the tin whisker mitigation behavior. In order to improve the coating adhesion, tin surface was also treated with a silane adhesion promoter before coating was applied. Furthermore, the effect of electron beam irradiation was investigated as it degraded the coating properties and adhesion. The results show that maintaining good adhesion and suppressing the degradation of mechanical properties of conformal coatings during various environmental exposures are essential for enhanced tin whisker mitigation.

Comparative effect of high energy electron beam and 137Cs gamma ray on survival, growth and chlorophyll content in curcuma hybrid ‘Laddawan’ and determine proper dose for mutations breeding

Curcuma alismatifolia is an ornamental plant with a beautiful flower in the curcuma genus, which is popular in Thailand and other countries. C. alismatifolia has been improved as the market needs. This research aimed to induce mutations and to study the effects of electron beam and gamma ray on tissue culture of the Curcuma hybrid ‘Laddawan.’ Eight-weeks-old plantlets were irradiated by gamma ray with a Mark I irradiator at the dose rate of 3.74 Gy/min, at the Nuclear Technology Research Center, Kasetsart University. For the electron beam irradiation, samples were exposed to a high-energy electron beam. The lowest power of this machine is 10 MeV and the lowest radiation dose per cycle is 50 Gy (240 Gy/min). The comparison between the effects of gamma ray and electron beam irradiation at doses of 0, 50, 100 and 200 Gy showed that survival percentage, growth percentage, and chlorophyll content were significantly decreased (P<0.05) when radiation dose increased. The survival percentage, growth percentage and chlorophyll content of gamma-irradiated samples were higher than the electron beam-irradiated samples in the same dose. The results indicated the optimum dose range for gamma irradiation of Curcuma hybrid ‘Laddawan’ in tissue culture is 30 – 60 Gy and for electron beams the dose should be less than 50 Gy. New characteristics (variegated leaves and light green leaves) were found in M1V2.

Efficacy of e-beam irradiation on shelf-life and accompanied changes in major metabolites of Desmodium gangeticum (L.) DC., an Ayurveda medicinal plant

The effects of electron beam irradiation (5, 10 and 15 kGy) on shelf-life and major plant metabolites of an Ayurvedic medicinal plant Desmodium gangeticum was evaluated. Its root possesses incredible medicinal effects; hence powdered root sample (choorna) was subjected to radiation processing and thereby shelf-life extension. The root sample was found to possess an appreciable amount of phenolic and flavonoid compounds. Processing with radiation did not produce prominent changes in the phenolic content of samples even after storage for up to 12 months. In contrast, Calcium content was increased significantly (p < 0.05) on radiation processing wit 5 kGy and 15 kGy. Microbial status revealed that the untreated sample was acceptable only up to 4 months. A dose-dependent reduction in the microbial count resulted in all the radiation processed samples. Treatment with doses of 10 kGy and 15 kGy reduced the colony count to nil immediately after irradiation. Irradiation with 15 kGy kept the sample completely sterilized up to 2 months of storage and was acceptable even 12th month of storage. GC-MS analyses identified compounds with pharmacological importance such as methyl palmitate, mome-inositol, Neophytadiene, etc. Although, a slight change in mineral composition and phytochemicals were observed it could effectively decontaminate the medicinal herb and increase the shelf-life with minimum loss of major metabolites compared to other conventional methods of processing.

Cathodoluminescence degradation study of the green luminescence of ZnO nanorods

Bright green luminescence at 500 nm was obtained from chemical bath deposited ZnO nanorods after annealing in a reducing atmosphere (H2/Ar) at 700 °C for 30 min. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and secondary electron microscopy (SEM) were used to study the effect of electron beam irradiation on the cathodoluminescence (CL) and the surface state of the sample. The CL intensity was monitored concurrently with the Auger peak-to-peak heights (APPHs) using the same electron beam for both techniques. CL intensity degradation was studied in vacuum and in an oxygen ambient. According to the AES spectra, all the principal elements (zinc and oxygen) were detected as well as carbon, which was removed at the initial stage of electron beam irradiation. No chemical change was observed during electron beam irradiation. In vacuum, the CL intensity decreased to almost half of its initial intensity after 100 C/cm2 electron dose and then stabilized. In the oxygen atmosphere, the CL intensity also decreased initially up to a dose of ~10 C/cm2 and thereafter recovered to about 90% of its original intensity and stabilized after a dose of ~100 C/cm2. No difference in the chemical state of Zn was observed with XPS for the original sample and the degraded ones. Only a small change in the defect contribution part of the O peak was observed. SEM images for the original and degraded samples showed that the electron beam irradiation induced surface changes in the morphology of the ZnO nanorods. Generally, the CL intensity was very stable under electron beam irradiation, suggesting that the material may be suitable for application in optoelectronics devices.

Effect of Electron Beam Irradiation and Ionic Liquid Combined Pretreatment Method on Various Lignocellulosic Biomass

The objective of this study was to characterize the performance of lignocellulosic biomass (LCB) to assess its use as a potential bioethanol or biofuels through pretreatment process. The pretreatment process was performed to remove crystalline structural of biomasses in order to improve enzymatic hydrolysis process. In this work, combined electron beam irradiation and ionic liquid method was used as the pretreatment process for various LCBs such as Gigantochloa albociliata (GA), Leucaena leucocephala (LL), oil palm frond (OPF), acacia and microcrystalline cellulose (MCC) as reference. Irradiation dose was measured through electron beam accelerator over a range of 100-1000 kGy. Ionic liquid (IL) is known as green solvent that can dissolve cellulose. 50% v/v 1-ethyl-3-methylimidazolium acetate (EMIMAc) IL was employed to enhance the effect of irradiation in pretreatment process. The LCBs was analyzed by using two method; Fourier transform infrared (FTIR) and X-ray diffraction (XRD). FTIR result shows different pattern of spectra and peak for each condition. Lateral order index (LOI) based on Beer’s Law was also calculated to determine the changes in structure order after pretretament. For XRD results, the crystallinity index (CrI) of pretreated LCBs was calculated by using Segal’s Equation in order to determine the pattern based on different conditions. The highest percentage of effectiveness showed by pretreated Acacia as the values of LOI and CrI is the lowest compared to other LCBs which is 41.77% and 25.21%, respectively.

Effects of Electron Beam Irradiation on Insulation Characteristics of Epoxy/AlN Nanocomposites

Superconducting magnet is one of the core components of international thermonuclear experimental reactor (ITER). Due to the harsh operating environment, for the sake of ensuring the stable operation of the superconducting magnet, the superconducting magnet insulation is required to have excellent electrical and irradiation resistance. However, pure epoxy resin is difficult to adapt to the harsh environment in the ITER, so it needs to be modified to improve its insulation performance. In this paper, the epoxy/AlN nanocomposites with 1 wt% filler content of AlN nanoparticles were prepared, and the dispersion of nanoparticles was observed. High-energy electron beam was used to treat nanocomposites with the dose of 300, 500, and 700 kGy. The relative permittivity and conductivity of the nanocomposites after irradiation were tested. In addition, the data of surface potential were measured after surface charging for analyzing the dynamic behavior of surface charge and calculating the trap distribution of the nanocomposites with various irradiation doses. The flashover voltage of the nanocomposites influenced by irradiation in LN2 was also analyzed. The results show that irradiation can cause the change of trap distribution and flashover voltage, and the change trend is not monotonous.

Low Energy Effect of Electron Beam Irradiation on Si Solar Cells.

We investigated the change in the cell efficiency resulting from electron beam accelerated irradiation to understand the possibility of using silicon solar cells with nano-surfaces for satellites. The Si solar cells were made of 6″ micro-textured p-type Si wafers. The Si solar cells were fabricated using a standard cell fabrication process, including POCl₃ diffusion, anti-reflection coating layer deposition, and metal contact and co-firing heat treatment. After manufacturing the cell, we irradiated the cell with a low-energy electron beam to determine its effect. We analyzed the changes in the cell resulting from the irradiation with the electron beam by evaluating the photo-reflectance, transmission electron microscopy, electroluminescence and current-voltage curve.

Investigation of the effect of electron beam irradiation on the structural and transport properties of half doped Nd0.5Sr0.5MnO3 manganites

A systematic investigation on the effect of electron beam irradiation on the structural, electrical properties and thermopower of half doped Nd0.5Sr0.5MnO3 manganites is presented in this report. Elemental analysis of the samples through Energy Dispersive X-ray Spectroscopy (EDS) confirm the desired stoichiometry. Rietveld refinement of the X Ray diffraction data reveals that the samples are single phased. Further, no change in crystal structure or symmetry is observed as an after-effect of electron beam radiation. The samples exhibit insulating behaviour in the entire temperature range 10–300 K. Though the resistivity value changes as a result of electron beam irradiation but the insulating behaviour is unaffected. It is validated from both resistivity as well as thermopower analysis that small polarons are responsible for conduction in the high temperature region. On the contrary, variable range hopping is responsible for the conduction mechanism at low temperatures. The absolute value of thermopower is observed to decrease with increasing dose of electron beam. Moreover, thermopower data indicates n-type conductivity for the samples under investigation.

Effects of electron-beam irradiation on the quality characteristics of mandarin oranges (Citrus unshiu (Swingle) Marcov) during storage

Consumption and global utilization of mandarins is on the rise due to its easy-to-peel attribute compared to other citrus fruits. Mandarins are irradiated as an effective phyto-sanitary treatment for trade requirements. In this study, mandarins were irradiated with 0.4 and 1 kGy electron-beam as approved by United States Department of Agriculture (USDA), and changes in microbial and physicochemical characteristics during storage were monitored at 4 °C for 15 d. Microbial proliferation during storage was noticeable in non-irradiated fruits, whereas irradiated mandarins showed dose-dependent inhibition up to 15 d. Irradiation did not affect its moisture, total phenolics, and vitamin C. However, hardness, organic acids, hesperidin, radical scavenging activity, reducing and free sugars significantly decreased in all samples after 5 d of storage. Although, irradiation at 0.4 and 1 kGy could not prevent changes in stored mandarins, 0.4 kGy did not affect the major constituents and physical quality of mandarins, while providing microbial decontamination.

Preparation of reduced graphene oxide electrodes treated by electron beam irradiation and their electrochemical behaviors

We have demonstrated the preparation of reduced graphene oxide (RGO) using a two-step synthesis by a modified Hummer’s method and borohydride reduction. To study effect of electron beam irradiation to RGO-based electrodes, the samples were prepared by changing the exposure dose of radiation. The structure and morphology analysis was performed by scanning electron microscopy, Fourier transform infra-red spectroscopy (FT-IR) and X-ray diffraction. Electrochemical properties were characterized by cyclic voltammetry and galvanostatic charge–discharge tests were performed in 6 M KOH. The maximum specific capacitance of 200 kGy RGO at a current density of 1 A/g was 273.5 F/g. The RGO electrode irradiated by electron beam with the dose of 200 kGy showed the best energy storage performance such as high capacitance and good rate capability. As a result of this study, the RGO irradiated by an electron beam showed superior capacitance than did pristine RGO.

Effect of radiation on vinyl-methyl-polysiloxane and phenyl-vinyl-methyl-polysiloxane elastomers cured with different co-agents: Comparative study of mechanical and relaxation properties

The objective of this comparative study is to investigate the effects of electron-beam irradiation on the mechanical and stress relaxation properties of vinyl-methyl-polysiloxane (VMQ) and phenyl-vinyl-methyl-polysiloxane (PVMQ), as well the variation of these properties with irradiation depending on the silicone and co-agent type. For this purpose, firstly a series of silicone mixtures was prepared using 2,5-bis(tert-butylperoxy)−2,5-dimethylhexane as the peroxide and either a Type I (ZDA) or Type II co-agent (TAIC). The rheological properties and curing conditions of the prepared mixtures were investigated by rubber process analyzer. In the second step, cured elastomers were irradiated with electron beams at doses of 0–80 kGy. The percent gelation of elastomers before and after irradiation was determined by sol–gel analysis. In order to investigate the effects of irradiation on the mechanical properties and cross-link density, the stress–strain behavior was determined. The stress relaxation properties of samples were determined by temperature scanning stress relaxation technique. After the irradiation, it was found that the main effect of irradiation on the silicone elastomers is cross-linking. Irradiation increased the cross-link density for both the silicone and gel fraction up to 94.3% for PVMQ and 96.7% for VMQ. A higher cross-link density was achieved for all of the non-irradiated and irradiated PVMQ elastomers than for VMQ elastomers. The relaxation studies revealed that elastomer type and irradiation are two important parameters affecting the relaxation behaviors of silicone elastomers. Increasing the irradiation dose resulted in maintaining of mechanical properties owing to the isothermal relaxation of both VMQ and PVMQ elastomers. This improvement was higher in the VMQ elastomers. In non-isothermal or temperature scanning stress relaxation behavior, an increase in the irradiation dose resulted in an improvement in the properties of the VMQ elastomers and a decrease for the PVMQ elastomers. The reason for this reduction is thought to be some undesirable side reactions occurring with the free radicals stabilized by the phenyl groups during irradiation and that these groups accelerate the decomposition at high temperatures during the relaxation experiments.

Methodical engineering of defects in MnXZn1-X O(x = 0.03, and 0.05) nanostructures by electron beam for nonlinear optical applications: A new insight

A series of MnxZn1-xO (x = 0.03, 0.05) nanostructures have been grown via the solution based chemical spray pyrolysis technique. Electron beam induced modifications on structural, linear and nonlinear optical and surface morphological properties have been studied and elaborated. GXRD (glancing angle X-ray diffraction) patterns show sharp diffraction peaks matching with the hexagonal wurtzite structure of ZnO thin films. The upsurge in e-beam dosage resulted in the shifting of XRD peaks (101) and (002) towards lower angle side, and increase in FWHM value. Gaussian deconvolution on PL spectra reveals the quenching of defect centers, implying the role of electron beam irradiation regulating luminescence and defect centers in the nanostructures. Irradiation induced spatial confinement and phonon localization effects have been observed in the films via micro Raman studies. The later are evident from spectral peak shifts and broadening. Detailed investigations on the effect of electron beam irradiation on third order nonlinear optical properties under continuous and pulsed mode of laser operation regimes are deliberated. Third order absorptive nonlinearity of the nanostructures evaluated using the open aperture Z-scan technique in both continuous and pulsed laser regimes shows strong nonlinear absorption coefficient β eff of the order 10-4 cm/W confirming their suitability for passive optical limiting applications under intense radiation environments. Laser induced third harmonic generation (LITHG) experiment results supports the significant variation in nonlinearities upon electron beam irradiation, and the effect can be utilized for frequency conversion mechanisms in high power laser sources and UV light emitters.

Degradation of plastics via electron-beam distillation

The effect of electron beam irradiation on the dry distillation of plastics waste and their artificial mixtures with lignocelluloses as well as refuse derived fuel (RDF) was studied. It was found that irradiation makes it possible to reduce the temperature of dry distillation and increase the yield of wax/oil from plastics. Wax/oil obtained via the radiation-thermal degradation of plastics contains more of saturated components. Wax/oil yield is at least 2/3 of the initial RDF sample. Radiation-thermal degradation of the cellulose fraction of RDF produces mainly derivatives of furans.

Bulk defects and surface state dynamics in topological insulators: The effects of electron beam irradiation on the ultrafast relaxation of Dirac fermions in Bi2Te3

One of the most important challenges in the study of topological insulators is the realization of materials that are really insulating in the bulk, in order to emphasize quantum transport in the protected surface states. Irradiation with electron beams is a very promising approach toward this goal. By studying a series of samples of the prototype 3D topological insulator Bi2Te3, we show that while the topological properties of Dirac surface states are preserved after electron irradiation, their relaxation dynamics are very sensitive to the related modifications of the bulk properties. Using time- and angle-resolved photoelectron spectroscopy, we can reveal two distinct relaxation regimes after optical excitation for non-irradiated and irradiated samples. While the faster regime, corresponding to the first few picoseconds, presents a similar temporal evolution of the photoexcited population for all studied samples, the slower regime is strongly influenced by the controlled generation of defects in the bulk lattice. By adjusting the irradiation parameters in this class of materials, one can thus not only change the bulk transport properties but also tune the ultrafast response of the topological surface states.

Effect of electron beam irradiation on the structural characteristics and functional properties of rice proteins.

A study of the structural and functional changes of rice proteins (RPs) induced by electron beam irradiation (EBI) at 5 kGy, 10 kGy, 20 kGy, and 30 kGy was performed. The microcosmic surface structures of the RPs were changed and fragmented due to irradiation damage occurring on the RP surfaces. The changes in the UV visible spectra, intrinsic fluorescence spectra, surface hydrophobicity and SH and SS group contents indicated that the RPs unfolded after EBI treatment. In addition, the degree of conformational change was increased with increasing EBI treatment doses. FTIR analysis showed that the secondary structure redistributed, showing decreases in α-helices and concomitant increases in β-sheets, β-turns and random coils. The functional properties, emulsifying abilities, water adsorption capacities and oil adsorption capacities of the irradiated RPs improved dose-dependently, with maximums occurring at 30 kGy. The foaming properties were also enhanced by EBI; however, this effect was not dose-dependent. In contrast, all of the samples irradiated by electron beams presented lower emulsion stability than the control (0 kGy). These results provide a theoretical basis for the application of EBI in improving protein properties in the future.

Effects of Electron-Beam Irradiation on Graphene Oxide

Graphene oxide (GO) is a nanofilm composed of graphene with various oxygen functional groups attached. GO is of interest due to its unique mechanical-enhancement properties, its tunable electronic properties, and its potential use in the wide-scale production of graphene. Scanning electron microscopes (SEMs) are frequently used to characterize and study GO films. The purpose of this project was to study the effects of SEM-imaging on GO films. Using an SEM, we irradiated GO samples at electron beam-energies of 10, 20, and 30 keV (at a constant emission current of ∼40 ± 2 μA) for times ranging from 15 minutes to 1 hour. Raman D- and G-band intensities were used to examine structural modifications/damage to GO samples as a function of beam energy and exposure time. The results suggest that imaging with a 30 keV electron beam for 30 minutes may lead to the formation of amorphous carbon, while imaging with 10 keV or 20 keV beams for 30 minutes does not have a significant effect on GO samples.

Comparison of gamma and electron beam irradiation for using phyto-sanitary treatment and improving physico-chemical quality of dried apricot and quince

ABSTRACTThe present study was conducted to compare the effect of gamma and electron beam irradiation for use a phyto-sanitary treatment and improving the physico-chemical and antioxidant activity o...

Effect of 8 MeV electron beam irradiation on the structural, optical and electrical properties of a PANI-MnWO4 nanocomposite

The effect of 8MeV electron beam irradiation on the structural, optical and electrical properties of a PANI-MnWO4 nanocomposite synthesized by in situ chemical oxidative polymerization in the presence of MnWO4 nanoparticles was investigated. The dose-dependent effect of electron irradiation was studied using various characterization techniques, such as X-ray diffraction, Fourier-transformed infrared spectroscopy, UV-vis absorption spectroscopy and impedance analyser. Systematic investigation based on the results of structural studies confirms that electron beam irradiation induces defects and particle size variation on the PANI-MnWO4 nanocomposite, which in turn results in improvements in optical absorption, band gap, DC and AC conductivity, and dielectric constant and loss tangent.

Effects of electron beam irradiation on storability of brown and milled rice

The effects of electron beam irradiation (EBI) treatment on the freshness and quality of brown and milled rice at different irradiation doses were investigated. The colors of brown rice (P > 0.05) and milled rice (P < 0.05) slightly changed after 5 kGy irradiation. After irradiation, the viscosities and amylose contents of the samples decreased (P < 0.05), crystal forms remained unchanged, but crystallinities decreased (P < 0.05). The microstructures of the samples did not change according to the results of the scanning electron microscopy. During the 120-day storage process, the free fatty acids of the irradiated samples increased at a slower rate than the non-irradiated samples did. Lipase activity was inhibited effectively, and the total viable bacterial count was significantly reduced (P < 0.05). Results indicated the potential of EBI to improve the quality and extend the shelf lives of brown and milled rice during storage.