Articles de revues : « Radiolyse de surface »

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Erlandsen, Stanley, Ming Lei, Ines Martin-Lacave, Gary Dunny et Carol Wells. « High Resolution CryoFESEM of Microbial Surfaces ». Microscopy and Microanalysis 9, n^o 4 (août 2003) : 273–78. http://dx.doi.org/10.1017/s1431927603030502.

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The outer surfaces of three microorganisms, Giardia lamblia, Enterococcus faecalis, and Proteus mirabilis, were investigated by cryo-immobilization followed by sublimation of extracellular ice and cryocoating with either Pt alone or Pt plus carbon. Cryocoated samples were examined at −125°C in either an in-lens field emission SEM or a below-the-lens field emission SEM. Cryocoating with Pt alone was sufficient for low magnification observation, but attempts to do high-resolution imaging resulted in radiolysis and cracking of the specimen surface. Double coating with Pt and carbon, in combination with high resolution backscatter electron detectors, enabled high-resolution imaging of the glycocalyx of bacteria, revealing a sponge-like network over the surface. High resolution examination of bacterial flagella also revealed a periodic substructure. Common artifacts included radiolysis leading to “cracking” of the surface, and insufficient deposition of Pt resulting in the absence of detectable surface topography.

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Mukherjee, Smita, Marie-Claude Fauré, Michel Goldmann et Philippe Fontaine. « Two step formation of metal aggregates by surface X-ray radiolysis under Langmuir monolayers : 2D followed by 3D growth ». Beilstein Journal of Nanotechnology 6 (15 décembre 2015) : 2406–11. http://dx.doi.org/10.3762/bjnano.6.247.

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In order to form a nanostructured metallic layer below a Langmuir monolayer, radiolysis synthesis was carried out in an adapted geometry that we call surface X-ray radiolysis. In this procedure, an X-ray beam produced by a synchrotron beamline intercepts the surface of an aqueous metal-ion solution covered by a Langmuir monolayer at an angle of incidence below the critical angle for total internal reflection. Underneath the organic layer, the X-ray beam induces the radiolytic synthesis of a nanostructured metal–organic layer whose ultrathin thickness is defined by the vertical X-ray penetration depth. We have shown that increasing the X-ray flux on the surface, which considerably enhances the kinetics of the silver layer formation, results in a second growth regime of silver nanocrystals. Here the formation of the oriented thin layer is followed by the appearance of a 3D powder of silver clusters.

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Duński, H., R. Leszczyński et S. Wysocki. « Benzene gamma-radiolysis on MgO surfaces ». Journal of Radioanalytical and Nuclear Chemistry Articles 152, n^o 2 (décembre 1991) : 329–35. http://dx.doi.org/10.1007/bf02104686.

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Imanova, Gunel. « Molecular hydrogen production by radiolysis of water on the surface of nano-ZrO2 under the influence of gamma rays ». Synthesis and Sintering 2, n^o 1 (19 février 2022) : 9–13. http://dx.doi.org/10.53063/synsint.2022.21105.

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In this research, the radiation-heterogeneous processes of water decomposition on the surface of zirconium dioxide nanoparticles (n-ZrO2) were studied. The kinetics of buildup of molecular hydrogen during the radiolytic processes of water decomposition was also examined. The production of H2 and H2O2 through water radiolysis was investigated to develop a computational model and disclose the kinetic behavior of water radiolysis. The enthalpy of ZrO2 nanoparticles was studied at the temperature range T=1200-2900 K, in which ZrO2 nanoparticles has a two-phase transition. Some of the electrons were transported to the surface of the nanoparticles during the physical and physicochemical stages of the process and emitted into the water. At the same time, the migration of energy carriers in radioactively active oxide compounds changed at different intervals depending on the composition, structural stability, and electro-physical properties of the oxides.

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Wang, Honglong, Yaping Sun, Jian Chu, Xu Wang et Ming Zhang. « Intensive study on structure transformation of muscovite single crystal under high-dose γ -ray irradiation and mechanism speculation ». Royal Society Open Science 6, n^o 7 (juillet 2019) : 190594. http://dx.doi.org/10.1098/rsos.190594.

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Intensive study on structure transformation of muscovite single crystal under high-dose γ -ray irradiation is essential for its use in irradiation detection and also beneficial for mechanism cognition on defect formation within a matrix of clay used in the disposal of high-level radioactive waste (HLRW). In this work, muscovite single crystal was irradiated with Co-60 γ ray in air at a dose rate of 54 Gy min −1 with doses of 0–1000 kGy. Then, structure transformation and mechanism were explored by Raman spectrum, Fourier-transform infrared spectrum, X-ray diffraction, thermogravimetric analysis, CA, scanning electron microscope and atomic force microscopy. The main results show that variations in the chemical/crystalline structure are dose-dependent. Low-dose irradiation sufficiently destroyed the structure, removing Si–OH, thus declining hydrophilicity. With dose increase up to 100 kGy, CA increased from 20° to 40°. Except for hydrophilicity variation, shrink occurred in the (004) lattice plane which later recovered; the variation range at 500 kGy irradiation was 0.5% close to 0.02 Å. The main mechanisms involved were framework break and H 2 O radiolysis. Framework break results in Si–OH removal and H 2 O radiolysis results in extra OH introduction. The extra introduced OH probably results in Si–OH bond regeneration, lattice plane shrink and recovered surface hydrophilicity. The importance of framework break and H 2 O radiolysis on structure transformation is dose-dependence. At low doses, framework break seems more important while at high doses H 2 O radiolysis is important. Generally, variations in the chemical structure and surface property are nonlinear and less at high doses. This indicates using the chemical structure or surface property variation to describe irradiation is correct at low doses but not at high doses. This finding is meaningful for realizing whether muscovite is suitable for detecting high-dose irradiation or not, and mechanism exploration is efficient for identifying the procedure for defect formation within the matrix of clay used in disposal HLRW in practice.

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Reiff, Sarah C., et Jay A. LaVerne. « Radiolysis of water with aluminum oxide surfaces ». Radiation Physics and Chemistry 131 (février 2017) : 46–50. http://dx.doi.org/10.1016/j.radphyschem.2016.10.022.

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Yamaguchi, Akinobu, Ikuya Sakurai, Ikuo Okada, Hirokazu Izumi, Mari Ishihara, Takao Fukuoka, Satoru Suzuki et Yuichi Utsumi. « Solid/liquid-interface-dependent synthesis and immobilization of copper-based particles nucleated by X-ray-radiolysis-induced photochemical reaction ». Journal of Synchrotron Radiation 27, n^o 4 (19 mai 2020) : 1008–14. http://dx.doi.org/10.1107/s1600577520005184.

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X-ray-radiolysis-induced photochemical reaction of a liquid solution enables the direct synthesis and immobilization of nano/micro-scale particles and their aggregates onto a desired area. As is well known, the synthesis, growth and aggregation are dependent on the pH, additives and X-ray irradiation conditions. In this study, it was found that the topography and composition of synthesized particles are also dependent on the types of substrate dipped in an aqueous solution of Cu(COOCH3)2 in the X-ray-radiolysis-induced photochemical reaction. These results are attributed to the fact that a secondary electron induced by the X-ray irradiation, surface or interface on which the particles are nucleated and grown influences the particle shape and composition. This study will shed light on understanding a novel photochemical reaction route induced under X-ray irradiation. The development of this process using the X-ray-radiolysis-induced photochemical reaction in aqueous liquids enables us to achieve the rapid and easy operation of the synthesis, growth and immobilization of special nano/micro-scale complex materials or multifunctional composites.

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Ubaldini, Alberto, Chiara Telloli, Antonietta Rizzo, Alessandro Gessi, Giuseppe Marghella, Stefania Bruni, Sara Calistri, Francesco Gennerini et Georgiana Pintilei. « A Study of Accelerated Corrosion of Stainless Steels under Highly Oxidizing Conditions ». Coatings 14, n^o 4 (27 mars 2024) : 390. http://dx.doi.org/10.3390/coatings14040390.

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The corrosion behavior of certain steels under extremely oxidative conditions, simulating the impact of water radiolysis on stainless steels, has been investigated. Radiolysis generates aggressive species, including radicals, solvated electrons, and hydrogen peroxide, potentially leading to corrosion over time in materials typically considered resistant. To expedite the kinetics of this phenomenon, drastic conditions were employed, involving high concentrations of peroxide in a strongly acidic environment. Under these conditions, corrosion can manifest rapidly. The varied responses of different steels are contingent upon their inherent nature and chemical composition, notably the chromium and nickel content. Steels with higher chromium and nickel concentrations exhibit increased resistance to corrosion, even in such severe environments. Microscopic corrosion mechanisms involve pitting and intergranular corrosion. Pitting results in the formation of craters on surfaces, while intergranular corrosion leads to the detachment of grains.

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Carrasco-Flores, Eduardo A., et Jay A. LaVerne. « Surface species produced in the radiolysis of zirconia nanoparticles ». Journal of Chemical Physics 127, n^o 23 (21 décembre 2007) : 234703. http://dx.doi.org/10.1063/1.2806164.

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Colín-García, M., F. Ortega-Gutiérrez, S. Ramos-Bernal et A. Negrón-Mendoza. « Heterogeneous radiolysis of HCN adsorbed on a solid surface ». Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment 619, n^o 1-3 (juillet 2010) : 83–85. http://dx.doi.org/10.1016/j.nima.2009.10.074.

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Муссаева, М. А., et Э. М. Ибрагимова. « Электронная микроскопия и элементный состав приповерхностного слоя кристаллов LiF, облученных электронами ». Письма в журнал технической физики 45, n^o 4 (2019) : 34. http://dx.doi.org/10.21883/pjtf.2019.04.47335.17583.

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AbstractElectron microscopy and optical vibrational spectroscopy techniques have been used to study Li nanoparticles formed on the cleaved surface of lithium fluoride (LiF) crystals irradiated by 4-MeV electron beam to a total fluence of 5 × 10^16 cm^–2. It is suggested that ionization accompanying this intense irradiation leads to radiolysis of the target and removal of fluorine from interblock boundaries, where lithium cations are collected and mutually oriented to form microwires. This functional surface may be of practical interest.

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Nermin Mammadova, Ulviyya Guliyeva, Nermin Mammadova, Ulviyya Guliyeva, et Muslim Gurbanov Muslim Gurbanov. « RADIOLYSIS OF INDUSTRIAL WASTEWATER IN THE PRESENCE OF NANO-γ-Al2O3 UNDER THE INFLUENCE OF γ-RADIATION ». PAHTEI-Procedings of Azerbaijan High Technical Educational Institutions 33, n^o 10 (12 septembre 2023) : 82–89. http://dx.doi.org/10.36962/pahtei33102023-82.

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The kinetics of changes in the concentration of toxic components under γ-irradiation of industrial wastewater from an oil refinery in the presence of nano-γ-Al2O3 has been studied. The concentration of phenols, surfactants, COD and the total content of oil products at various adsorbed dose were monitored. UV - spectrometric studies of irradiated samples in the range of 200-400 nm shows, that increasing the absorbed dose leads to a decrease in UV - absorption (Abs) in the region of 200-210 nm. The mechanism of the observed regularities is discussed, including radiation-chemical processes occurring in the liquid phase, the participation of electron-donor centers in the decomposition of adsorbed molecules and adsorption of radiolysis products on the surface of nano-γ-Al2O3. Keywords: Radiolysis, nano-γ-Al2O3, wastewater, surfactants, oil products, COD.

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Jin, Binbin, Ding Zhao, Fei Liang, Lufang Liu, Dongli Liu, Pan Wang et Min Qiu. « Electron-Beam Irradiation Induced Regulation of Surface Defects in Lead Halide Perovskite Thin Films ». Research 2021 (4 juin 2021) : 1–11. http://dx.doi.org/10.34133/2021/9797058.

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Organic-inorganic hybrid perovskites (OIHPs) have been intensively studied due to their fascinating optoelectronic performance. Electron microscopy and related characterization techniques are powerful to figure out their structure-property relationships at the nanoscale. However, electron beam irradiation usually causes damage to these beam-sensitive materials and thus deteriorates the associated devices. Taking a widely used CH3NH3PbI3 film as an example, here, we carry out a comprehensive study on how electron beam irradiation affects its properties. Interestingly, our results reveal that photoluminescence (PL) intensity of the film can be significantly improved along with blue-shift of emission peak at a specific electron beam dose interval. This improvement stems from the reduction of trap density at the CH3NH3PbI3 surface. The knock-on effect helps expose a fresh surface assisted by the surface defect-induced lowering of displacement threshold energy. Meanwhile, the radiolysis process consistently degrades the crystal structure and weaken the PL emission with the increase of electron beam dose. Consequently, the final PL emission comes from a balance between knock-on and radiolysis effects. Taking advantage of the defect regulation, we successfully demonstrate a patterned CH3NH3PbI3 film with controllable PL emission and a photodetector with enhanced photocurrent. This work will trigger the application of electron beam irradiation as a powerful tool for perovskite materials processing in micro-LEDs and other optoelectronic applications.

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Pastina, Barbara, et Jay A. LaVerne. « An Alternative Conceptual Model for the Spent Nuclear Fuel–Water Interaction in Deep Geologic Disposal Conditions ». Applied Sciences 11, n^o 18 (15 septembre 2021) : 8566. http://dx.doi.org/10.3390/app11188566.

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For the long-term safety assessment of direct disposal of spent nuclear fuel in deep geologic repositories, knowledge on the radionuclide release rate from the UO2 matrix is essential. This work provides a conceptual model to explain the results of leaching experiments involving used nuclear fuel or simulant materials in confirmed reducing conditions. Key elements of this model are: direct effect of radiation from radiolytic species (including defects and excited states) in the solid and in the first water layers in contact with its surface; and excess H2 may be produced due to processes occurring at the surface of the spent fuel and in confined water volumes, which may also play a role in keeping the spent fuel surface in a reduced state. The implication is that the fractional radionuclide release rate used in most long-term safety assessments (10−7 year−1) is over estimated because it assumes that there is net UO2 oxidation caused by radiolysis, in contrast with the alternative conceptual model presented here. Furthermore, conventional water radiolysis models and radiation chemical yields published in the literature are not directly applicable to a heterogeneous system such as the spent fuel–water interface. Suggestions are provided for future work to develop more reliable models for the long-term safety assessment of spent nuclear fuel disposal.

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Guipponi, C., N. Millard-Pinard, N. Bérerd, E. Serris, M. Pijolat, V. Peres et V. Wasselin-Trupin. « Modifications of oxidized Zircaloy-4 surface in contact with radiolysed wet air ». Nuclear Instruments and Methods in Physics Research Section B : Beam Interactions with Materials and Atoms 272 (février 2012) : 222–26. http://dx.doi.org/10.1016/j.nimb.2011.01.070.

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Trumbo, Samantha K., Michael E. Brown et Kevin P. Hand. « Sodium chloride on the surface of Europa ». Science Advances 5, n^o 6 (juin 2019) : eaaw7123. http://dx.doi.org/10.1126/sciadv.aaw7123.

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The potential habitability of Europa’s subsurface ocean depends on its chemical composition, which may be reflected in that of Europa’s geologically young surface. Investigations using Galileo Near-Infrared Mapping Spectrometer data led to the prevailing view that Europa’s endogenous units are rich in sulfate salts. However, recent ground-based infrared observations have suggested that, while regions experiencing sulfur radiolysis may contain sulfate salts, Europa’s more pristine endogenous material may reflect a chloride-dominated composition. Chlorides have no identifying spectral features at infrared wavelengths, but develop distinct visible-wavelength absorptions under irradiation, like that experienced on the surface of Europa. Using spectra obtained with the Hubble Space Telescope, we present the detection of a 450-nm absorption indicative of irradiated sodium chloride on the surface. The feature correlates with geologically disrupted chaos terrain, suggesting an interior source. The presence of endogenous sodium chloride on the surface of Europa has important implications for our understanding of its subsurface chemistry.

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Prabhala, Anupama. « Sustainable Development in Dye Waste Managemen : A Comparative Study on the Effectiveness of Adsorption and γ-Radiolysis ». Journal of ISAS 2, n^o 4 (30 avril 2024) : 1–22. http://dx.doi.org/10.59143/isas.jisas.2.4.kzbg4323.

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Pyrromethene 567 (PM567), a BODIPY class of dye; is widely used in medicine, chemistry, material science, and high-power dye lasers. During its use, PM567 dye waste is generated in ethanol solvent which needs to be treated before its disposal. In our study, we -radiolysis, an advanced oxidation process (AOP), and adsorption, a simple and easy option. Interestingly, -radiolysis were not efficient for dye effluent treatment in organic solvents. This inefficiency was attributed to competing reactions leading to the scavenging of dye-degrading radicals. -dose rate (3.5 kGy) feasible in the system; 62% is the maximum removal efficiency achieved by this method. For a comparison, we also investigated the adsorption efficiency of PM567 dye from ethanol solvent using commercially available adsorbents. Among these, powdered activated carbon (PAC) demonstrated the highest removal efficiency, reaching 95%, much higher than that of -radiolysis method. In line with the pursuit of sustainable development, we synthesized granular activated carbons (AC1, AC2, AC3) from coconut shells, a lignocellulosic biowaste. The characterization of these carbons revealed that AC3, with a higher iodine value and CCl4 activity, possessed a systematic pore structure (SEM analysis), a larger specific surface area (1708 m2 .g-1), and a higher micro-pore volume (0.61 cc.g-1). AC3 hence, emerged as the most effective adsorbent, achieving 95% efficiency comparable to PAC.

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Riba, O., E. Coene, O. Silva et L. Duro. « Spent fuel alteration model integrating processes of different time-scales ». MRS Advances 5, n^o 3-4 (2020) : 159–66. http://dx.doi.org/10.1557/adv.2020.51.

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ABSTRACTA 1D reactive transport model has been implemented in iCP (interface COMSOL Multiphysics and PhreeqC) to assess the corrosion of Spent Fuel (SF), considered as homogeneous UO2(am,hyd) doped with Pd. The model couples: i) generation of water radiolysis species by alpha and beta radiation considering the complete water radiolysis system with the kinetic reactions involving: H+, OH-, O2, H2O2, H2, HO2-, HO2·, O·, O-, O2-, H·, ·OH and e- ii) processes occurring in the spent fuel surface: oxidative dissolution reactions of UO2(am,hyd) and subsequent reduction of oxidized fuel, considering H2 activation by Pd, and iii) corrosion of Fe(s) in oxic and anoxic conditions. Process i) has been implemented in COMSOL and processes ii) and iii) have been implemented in PHREEQC with their kinetic constants being calibrated with different sets of experimental data published in the open literature. The model yields a UO2(am,hyd) dissolution rates similar to the values selected in safety assessments.

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Moreau, S., M. Fenart et J. P. Renault. « Radiolysis of water in the vicinity of passive surfaces ». Corrosion Science 83 (juin 2014) : 255–60. http://dx.doi.org/10.1016/j.corsci.2014.02.024.

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Fraxedas, Jordi, Kuan Zhang, Borja Sepúlveda, María José Esplandiu, Xènia García de Andrés, Jordi Llorca, Virginia Pérez-Dieste et Carlos Escudero. « Water-mediated photo-induced reduction of platinum films ». Journal of Synchrotron Radiation 26, n^o 4 (6 juin 2019) : 1288–93. http://dx.doi.org/10.1107/s1600577519004685.

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Platinum thin films activated ex situ by oxygen plasma become reduced by the combined effect of an intense soft X-ray photon beam and condensed water. The evolution of the electronic structure of the surface has been characterized by near-ambient-pressure photoemission and mimics the inverse two-step sequence observed in the electro-oxidation of platinum, i.e. the surface-oxidized platinum species are reduced first and then the adsorbed species desorb in a second step leading to a surface dominated by metallic platinum. The comparison with measurements performed under high-vacuum conditions suggests that the reduction process is mainly induced by the reactive species generated by the radiolysis of water. When the photon flux is decreased, then the reduction process becomes slower.

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Fontaine, P., M. C. Fauré, S. Remita, F. Muller et M. Goldmann. « X-ray surface radiolysis : Kinetics of the metal-organic interface formation ». European Physical Journal Special Topics 167, n^o 1 (février 2009) : 157–62. http://dx.doi.org/10.1140/epjst/e2009-00952-5.

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Kimura, Atsushi, Tadashi Arai, Miho Ueno, Kotaro Oyama, Hao Yu, Shinichi Yamashita, Yudai Otome et Mitsumasa Taguchi. « Synthesis of Small Peptide Nanogels Using Radiation Crosslinking as a Platform for Nano-Imaging Agents for Pancreatic Cancer Diagnosis ». Pharmaceutics 14, n^o 11 (7 novembre 2022) : 2400. http://dx.doi.org/10.3390/pharmaceutics14112400.

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Nanoparticle-based drug delivery systems (DDS) have been developed as effective diagnostic and low-dose imaging agents. Nano-imaging agents with particles greater than 100 nm are difficult to accumulate in pancreatic cancer cells, making high-intensity imaging of pancreatic cancer challenging. Peptides composed of histidine and glycine were designed and synthesized. Additionally, aqueous peptide solutions were irradiated with γ-rays to produce peptide nanogels with an average size of 25–53 nm. The mechanisms underlying radiation-mediated peptide crosslinking were investigated by simulating peptide particle formation based on rate constants. The rate constants for reactions between peptides and reactive species produced by water radiolysis were measured using pulse radiolysis. HGGGHGGGH (H9, H—histidine; G—glycine) particles exhibited a smaller size, as well as high formation yield, stability, and biodegradability. These particles were labeled with fluorescent dye to change their negative surface potential and enhance their accumulation in pancreatic cancer cells. Fluorescent-labeled H9 particles accumulated in PANC1 human pancreatic cancer cells, demonstrating that these particles are effective nano-imaging agents for intractable cancers.

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Deronzier, Jean-François, et Hélène Giouse. « Vaux-en-Bugey (Ain, France) : the first gas field produced in France, providing learning lessons for natural hydrogen in the sub-surface ? » BSGF - Earth Sciences Bulletin 191 (2020) : 7. http://dx.doi.org/10.1051/bsgf/2020005.

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The former Vaux-en-Bugey field, first French methane production from early 20th century, is revisited as a case study to address the present generation and accumulation theories for gases like hydrogen and helium. The volume of the initial gas in place is estimated to be 22 million m3. Based on a composition of 5% of hydrogen and 0.096% of helium, the volumes of these gases in the field were respectively around 1.1 million m3 for hydrogen and 24 000 m3 for helium. The different hypotheses of hydrogen sources are reviewed: serpentinization, hydro-oxidation of siderite, water radiolysis, bio-fermentation, mechanical generation, degassing from depth trough faults, steel corrosion. For helium generation, the different sources of radioactive minerals and intermediate accumulations are examined. The most probable scenario is the hydrogen production by water radiolysis and helium production by radioactive decay in or near the basement, migrating trough deep faults, stored and concentrating in an aquifer with thermogenic methane, then flushed by methane into the gas field, during Jura thrusting. New measurements with portable gas detector, incomplete but including hydrogen, on a former exploration well with accessible flux of gas, give the opportunity to comment gas saturation evolution more than a century after the 1906 discovery. The decreasing of hydrogen content since the discovery of the field is probably due to Sulphate-Reducing Bacteria activity.

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Garibov, Adil, Yadigar Jafarov, Gunel Imanova, Teymur Agayev, Sevinj Bashirova et Anar Aliyev. « Mechanism of Hydrogen Production in The Processes of Radiation Heterogeneous Splitting of Water with the Presence of Nano-Metal and Nano-MeO ». East European Journal of Physics, n^o 1 (5 mars 2024) : 460–75. http://dx.doi.org/10.26565/2312-4334-2024-1-51.

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In the study, the optimal values of the ratio of the distance between particles to the particle size in the radiation-heterogeneous radiolysis of water in nano-Me and nano-MeO systems were determined. In those systems, the effect of water density and system temperature on the radiation-chemical release of molecular hydrogen obtained from thermal and radiation-thermal decomposition of water was considered. The article also determined the effect of particle sizes and the type of sample taken on the radiation chemical yield of molecular hydrogen. In the presented article, the change of molecular hydrogen according to adsorbed water and catalyst was studied. Thus, in the case of a suspension of nano-zirconium in water, the energy of electrons emitted from the metal is completely transferred to water molecules, which leads to an increase in the yield of hydrogen. When radiolysis of water in the presence of nano-metals, energy transfer can be carried out mainly with the participation of emitted electrons. Therefore, in the case of radiolysis of water in suspension with n-Zr, the yield of hydrogen increases by 5.4 times compared to the processes of radiolysis in an adsorbed state. However, in radiation-heterogeneous processes of obtaining hydrogen from water in contact with metal systems, it is necessary to take into account that as a result of these processes surface oxidation occurs and after a certain time the systems are converted to n-Me-MeO+H2Oliq. systems. For nano sized oxide compounds, the mean free path of secondary electrons formed as a result of primary processes of interaction of quanta with atoms is commensurate with the particle sizes of nano-oxides (λ ≈ R_(H-оxides)). Further, these electrons interact with the electronic subsystem of silicon. For nanocatalysts, the length of free paths of secondary and subsequent generations of electrons is greater than the size of catalyst particles (R_cat≤100nm). Usually, their energy is sufficient to conduct independent radiolytic processes in the contact medium of the catalyst.

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Savchenko, Igor Dmitrovich, Anatoly Mikhailovich Kulabukhov, Viktor Alexandrovich Masalskiy et Aramais Viktorovich Tishchenko. « THE MODEL OF A RADIO LINK "SPACE-TO-EARTH" WITH MORE INFORMATIVE FOR A LOW ORBIT SATELLITE ». Journal of Rocket-Space Technology 27, n^o 4 (30 décembre 2019) : 9–12. http://dx.doi.org/10.15421/451902.

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A proposed the model of a radioline “space-to-Earth” with more informative for a low orbit university nanosatellite. The radioline is modeled on a antenna of the high-frequency S-band. At present time, the tasks of creating radiolines “space-to-Earth” in the conditions of limited energy of satellites with more informativeness (for telemetry radiolines and information radiolines) constantly require increasing their capabilities. Various options are being developed to implement such a solution, ranging from increasing the data transmission time due to repeaters and developing new encoding methods and increasing the bandwidth of radio lines. One solution is to use middle or high gain antennas. The model of a radioline is designed on the basis of the high-frequency (S-band) antenna. The calculations were carried out according to the international format of the AMSAT-IARU-Link-Model program. The calculation of the proposed the model consists of three basic conditions: the greatest loss of energy of the radio signal in free space, equivalent to isotropic radiating power and quality factor of the receiving station. The proposed model is built on the basis of a phased antenna array with a gain of 12 dBi for transmit from nanosatellite, the gain of the receiving antenna is 35 dBi. The results showed the ability to transmit up to 50 images of the Earth's surface per day. The use of a phased array antenna and the transition to the S-band allowed with smaller dimensions to increase the antenna gain and the rate of information transmission in communication sessions.

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Cassidy, T., P. Coll, F. Raulin, R. W. Carlson, R. E. Johnson, M. J. Loeffler, K. P. Hand et R. A. Baragiola. « Radiolysis and Photolysis of Icy Satellite Surfaces : Experiments and Theory ». Space Science Reviews 153, n^o 1-4 (23 février 2010) : 299–315. http://dx.doi.org/10.1007/s11214-009-9625-3.

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Ismailov, Abubakar, et Arsen Muslimov. « Etching of ZnO films by a focused flow electrons with medium energies (up to 70 keV) ». Applied Physics, n^o 5 (19 novembre 2021) : 75–80. http://dx.doi.org/10.51368/1996-0948-2021-5-75-80.

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Consideration is given to the results of the study of etching processes ( 200 nm/min) of a ZnO film by a focused electron beam with medium energy (70 keV) under vacuum conditions of 910-5 Pa. It was shown that the construction of a model of the ZnO film etching during electron bombardment, taking into account the likely thermal desorption and electron-stimulated desorption, is not confirmed by calculations. A possible etching mechanism based on the radiolysis caused by Auger decay in near-surface layers of ZnO films is proposed.

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Sárkány, A., P. Hargittai et O. Geszti. « Thermal and radiolysis assisted formation of Au–Pd heteroaggregates ». Colloids and Surfaces A : Physicochemical and Engineering Aspects 322, n^o 1-3 (juin 2008) : 124–29. http://dx.doi.org/10.1016/j.colsurfa.2008.02.045.

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Paulive, Alec, Christopher N. Shingledecker et Eric Herbst. « The role of radiolysis in the modelling of C2H4O2 isomers and dimethyl ether in cold dark clouds ». Monthly Notices of the Royal Astronomical Society 500, n^o 3 (7 novembre 2020) : 3414–24. http://dx.doi.org/10.1093/mnras/staa3458.

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ABSTRACT Complex organic molecules (COMs) have been detected in a variety of interstellar sources. The abundances of these COMs in warming sources can be explained by syntheses linked to increasing temperatures and densities, allowing quasi-thermal chemical reactions to occur rapidly enough to produce observable amounts of COMs, both in the gas phase, and upon dust grain ice mantles. The COMs produced on grains then become gaseous as the temperature increases sufficiently to allow their thermal desorption. The recent observation of gaseous COMs in cold sources has not been fully explained by these gas-phase and dust grain production routes. Radiolysis chemistry is a possible non-thermal method of producing COMs in cold dark clouds. This new method greatly increases the modelled abundance of selected COMs upon the ice surface and within the ice mantle due to excitation and ionization events from cosmic ray bombardment. We examine the effect of radiolysis on three C2H4O2 isomers – methyl formate (HCOOCH3), glycolaldehyde (HCOCH2OH), and acetic acid (CH3COOH) – and a chemically similar molecule, dimethyl ether (CH3OCH3), in cold dark clouds. We then compare our modelled gaseous abundances with observed abundances in TMC-1, L1689B, and B1-b.

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Gadzhieva, N. N., É. A. Samedov et Kh I. Abdullaeva. « IR spectroscopic study of methane adsorption and radiolysis on a BeO surface ». Journal of Applied Spectroscopy 62, n^o 6 (novembre 1995) : 1019–22. http://dx.doi.org/10.1007/bf02606751.

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Bruk, M. A., G. G. Isayeva, Ye Ya Yunitskaya, S. A. Pavlov et A. D. Abkin. « Features of the radiolysis of polymers on the surface of solid surfaces as exemplified by polymethyl methacrylate and polymethyl acrylate on aerosil ». Polymer Science U.S.S.R. 27, n^o 7 (janvier 1985) : 1703–9. http://dx.doi.org/10.1016/0032-3950(85)90367-3.

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Zaharescu, Traian, Radu Mirea, Tunde Borbath et Istvan Borbath. « Stability Qualification of Resins/Metallic Oxide Composites for Surface Oxidative Protection ». Polymers 16, n^o 3 (25 janvier 2024) : 333. http://dx.doi.org/10.3390/polym16030333.

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The accelerated degradation of alkyd resins via γ-irradiation is investigated using non-isothermal chemiluminescence. The stability qualification is possible through the comparison of emission intensities on a temperature range starting from 100 °C up to 250 °C under accelerated degradation caused by radiolysis scission. The measurements achieved in the samples of cured state resin modified by various inorganic oxides reveal the influence of metallic traces on the aging amplitude, when the thermal resistance increases as the irradiation dose is augmented. Even though the unirradiated samples present a prominent chemiluminescence intensity peak at 80 °C, the γ-processed specimens show less intense spectra under the pristine materials and the oxidation starts smoothly after 75 °C. The values of activation energies required for oxidative degradation of the sample subjected to 100 kGy are significantly higher in the composite states than in the neat resin. The degradation mechanism of polymerized resins is discussed taking into account the effects of fillers on the stability of studied epoxy resin at various temperatures when the degradation and crosslinking are in competition for the decay of free radical.

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Nordheim, T. A., L. H. Regoli, C. D. K. Harris, C. Paranicas, K. P. Hand et X. Jia. « Magnetospheric Ion Bombardment of Europa’s Surface ». Planetary Science Journal 3, n^o 1 (1 janvier 2022) : 5. http://dx.doi.org/10.3847/psj/ac382a.

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Abstract Jupiter’s moon Europa is exposed to constant bombardment by magnetospheric charged particles, which are expected to be a major source of physical and chemical surface modification. Here we have investigated the flux of magnetospheric ions at Europa’s surface by carrying out single particle tracing within realistic electromagnetic fields from multifluid magnetohydrodynamic simulations of the moon’s interaction with Jupiter’s magnetosphere. We find that magnetic field line draping and pileup leads to shielding and drastically reduced flux at low latitudes across Europa’s trailing (upstream) hemisphere. Furthermore, we find that magnetic induction within Europa’s subsurface ocean leads to additional shielding when the moon is located at high magnetic latitudes in Jupiter’s magnetosphere. Overall, we find that the high-latitude and polar regions on Europa receive the largest flux of magnetospheric ions. Both spacecraft and ground-based observations have previously identified a non–water ice surface species concentrated at Europa’s trailing (upstream) hemisphere, possibly hydrated sulfuric acid formed from radiolysis of water ice with implanted S ions. Our results demonstrate that the S ion flux across Europa’s equatorial trailing (upstream) hemisphere is strongly reduced, possibly indicating that the formation of the observed non–water ice species is controlled primarily by energy input from magnetospheric electrons, rather than the flux of S ions. We find that that O and S ions at >1 MeV energies have nearly uniform access to the surface, while energetic protons in this energy range are constrained to a “bull’s-eye” centered on the trailing (upstream) hemisphere.

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Yuan, Longfei, Taixin Zhou, Fengmin Jin, Guohong Liang, Yuxiang Liao, Aijuan Zhao et Wenbo Yan. « Transmission Electron Microscopy Peeled Surface Defect of Perovskite Quantum Dots to Improve Crystal Structure ». Materials 16, n^o 17 (1 septembre 2023) : 6010. http://dx.doi.org/10.3390/ma16176010.

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Transmission electron microscopy (TEM) is an excellent characterization method to analyze the size, morphology, crystalline state, and microstructure of perovskite quantum dots (PeQDs). Nevertheless, the electron beam of TEM as an illumination source provides high energy, which causes morphological variation (fusion and melting) and recession of the crystalline structure in low radiolysis tolerance specimens. Hence, a novel and facile strategy is proposed: electron beam peel [PbBr6]4− octahedron defects from the surface of QDs to optimize the crystal structure. TEM and high-angle annular dark-field scanning TEM (HAADF) tests indicate that the [PbBr6]4− octahedron would be peeled from the surface of QDs when QDs samples were irradiated under high-power irradiation, and then a clear image would be obtained. To avoid interference from a protective film of “carbon deposits” on the surface of the sample when using high resolution TEM, amorphous carbon film (15–20 nm) was deposited on the surface of QDs film and then characterized by TEM and HAADF. The detection consequences showed that the defection of PbBr2 on the surface of QDs will gradually disappear with the extension of radiation time, which further verifies the conjecture.

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Adhikari, S., Ravi Joshi et C. Gopinathan. « Hydrated Electrons in a Quaternary Microemulsion System : A Pulse Radiolysis Study ». Journal of Colloid and Interface Science 191, n^o 1 (juillet 1997) : 268–71. http://dx.doi.org/10.1006/jcis.1997.4951.

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Venault, Laurent, Arnaud Deroche, Jérémy Gaillard, Olivier Lemaire, Natalia Budanova, Jackie Vermeulen, Jérôme Maurin, Nicolas Vigier et Philippe Moisy. « Dihydrogen H2 steady state in α-radiolysis of water adsorbed on PuO2 surface ». Radiation Physics and Chemistry 162 (septembre 2019) : 136–45. http://dx.doi.org/10.1016/j.radphyschem.2018.09.022.

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Wang, Zheming, Eric D. Walter, Michel Sassi, Xin Zhang, Hailin Zhang, Xiaohong S. Li, Ying Chen et al. « The role of surface hydroxyls on the radiolysis of gibbsite and boehmite nanoplatelets ». Journal of Hazardous Materials 398 (novembre 2020) : 122853. http://dx.doi.org/10.1016/j.jhazmat.2020.122853.

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Wilson, Eric H., Sushil K. Atreya, Ralf I. Kaiser et Paul R. Mahaffy. « Perchlorate formation on Mars through surface radiolysis-initiated atmospheric chemistry : A potential mechanism ». Journal of Geophysical Research : Planets 121, n^o 8 (août 2016) : 1472–87. http://dx.doi.org/10.1002/2016je005078.

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Liang, Ying, Bin Fang, Fang Fang Lin et Xu Min Zhu. « Gamma Irradiation Assisted Synthesis of Ag/rGO Composites and their Surface Properties ». Materials Science Forum 898 (juin 2017) : 2224–30. http://dx.doi.org/10.4028/www.scientific.net/msf.898.2224.

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Ag/rGO composites were synthesized under gamma irradiation using silver nitrate and graphene oxide (GO) as the starting materials. Comparing with traditional methods, gamma irradiation is a simple and “green” technique. In the irradiation system, silver ions were reduced to silver nanoparticles (AgNPs) by the electrons generated from the radiolysis of solvent. GO nanosheets provided reactive sites for the formation of AgNPs and acted as a colloidal surfactant preventing the aggregation of AgNPs. Meanwhile, GO were partially reduced to reduced graphene oxide (rGO). X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscope, Raman spectra and UV-Vis absorption spectra were applied for the characterization of Ag/rGO composites. The results showed that the absorbed dose (3.1 kGy, 4.7 kGy, 9.4 kGy and 27.4 kGy) plays an important role in the size distribution of AgNPs and the reduction degree of GO nanosheetes. The Ag/rGO composites exhibit a broad absorption band at visible light due to the surface plasmon resonance of AgNPs. Because of the unique surface properties, Ag/rGO composites behave enhanced performance for the adsorption of organic dye from water.

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Gorman, Anthony A., I. Hamblett et E. J. Land. « A pulse radiolysis based singlet oxygen luminescence facility ». Journal of the American Chemical Society 111, n^o 5 (mars 1989) : 1876–77. http://dx.doi.org/10.1021/ja00187a051.

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Ciraj-Bjelac, O. F., M. S. Kovacevic, D. D. Kosutic et S. S. Stankovic. « Radijaciono opterecenje pacijenata u konvencionalnoj dijagnostickoj radiologiji - analiza radioloske prakse u Srbiji ». Acta chirurgica Iugoslavica 54, n^o 3 (2007) : 93–98. http://dx.doi.org/10.2298/aci0703093c.

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X-rays are by far most significant contributor to total population dose from man-made sources of radiation. Diagnostic reference levels provide frameworks to reduce variability. The aim of this study is to establish, for the first time, a baseline for national diagnostic reference levels in Serbia for the most common X-ray examination types. Dose estimates are based on measurements of kerma-area product and Entrance surface air kerma for at least ten patients for each examination type, in each of 16 randomly selected hospitals in Serbia. Mean, median and third quartile values of patient doses are reported. Results have shown wide variation of mean hospital doses. Entrance surface doses were compared with previously published diagnostic reference levels. Doses for all studied examination types except chest radiography were within European DRL. The reasons for dose variation are discussed. The findings emphasize the importance of regular patient dose measurement to ensure that patient doses are kept as low as reasonable achievable.

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Le Caër, Sophie. « Water Radiolysis : Influence of Oxide Surfaces on H2 Production under Ionizing Radiation ». Water 3, n^o 1 (28 février 2011) : 235–53. http://dx.doi.org/10.3390/w3010235.

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Demidov, S. V., T. N. Rudneva, U. Yu Allayarova, E. N. Klimanova, A. S. Allayarova, A. V. Shitikova, S. D. Chekalina et S. R. Allayarov. « Fourier Transform IR Spectroscopic Study of the Influence of a High Dose of Gamma Radiation on the Composition of Functional Groups in Potato Tubers ». Химия высоких энергий 57, n^o 4 (1 juillet 2023) : 319–26. http://dx.doi.org/10.31857/s0023119323040083.

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This article considers physicochemical changes in the composition of potato tubers gamma-irradiated to doses of 5000 kGy, as studied by Fourier transform IR spectroscopy. Functional groups in the powders of skin, pulp, and juice of irradiated tubers have been examined. The carbonization and radiationinduced oxidation of the molecules of tuber constituents have been established. At doses above 1000 kGy, the hardness of tubers was completely lost, the integrity of the skin surface was violated, and an intense release ofjuice began. It has been found that γ-radiolysis at a dose to 5000 kGy does not lead to the complete destruction of chemical bonds in the structure of the main compounds contained in potato tubers.

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Cachoir, C., Th Mennecart et K. Lemmens. « Effect of cement water on UO2 solubility ». MRS Proceedings 1665 (2014) : 267–73. http://dx.doi.org/10.1557/opl.2014.654.

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ABSTRACTTo assess the stability of spent fuel in the highly alkaline chemical environment of the Belgian Supercontainer design, static leach experiments were performed with depleted UO2 and 238Pu-doped UO2 at different SA/V ratios for 1.5 years in cement waters (11.7< pH < 13.5) at ambient temperature and under argon atmosphere. The influence of the calcium concentration on the uranium release was also investigated. While the ultrafiltered U(IV) concentration was 10-9-10-8 mol.L-1 and independent of the pH, the U(VI) release from the UO2 surface was enhanced by the OH- concentration, leading to soluble U concentrations up to 10-5 mol.L-1 at high SA/V and under the influence of radiolysis. Together with the high Ca concentration, this can lead to the formation of Ca-U(VI) colloids as precursor of Ca-U(VI) secondary phases, decreasing the soluble U concentration. The precipitation of Ca-U secondary phases was however not clearly evidenced by surface analyses.

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Zheng, Ming, Gang Xu, Jingcheng Pei, Xiangxin He, Peijun Xu, Ning Liu et Minghong Wu. « EB-radiolysis of carbamazepine : in pure-water with different ions and in surface water ». Journal of Radioanalytical and Nuclear Chemistry 302, n^o 1 (19 juillet 2014) : 139–47. http://dx.doi.org/10.1007/s10967-014-3322-8.

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Maleknia, Simin D., Janna G. Kiselar et Kevin M. Downard. « Hydroxyl radical probe of the surface of lysozyme by synchrotron radiolysis and mass spectrometry ». Rapid Communications in Mass Spectrometry 16, n^o 1 (2001) : 53–61. http://dx.doi.org/10.1002/rcm.543.

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Jamali, Vida, Cory Hargus, Assaf Ben-Moshe, Amirali Aghazadeh, Hyun Dong Ha, Kranthi K. Mandadapu et A. Paul Alivisatos. « Anomalous nanoparticle surface diffusion in LCTEM is revealed by deep learning-assisted analysis ». Proceedings of the National Academy of Sciences 118, n^o 10 (3 mars 2021) : e2017616118. http://dx.doi.org/10.1073/pnas.2017616118.

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The motion of nanoparticles near surfaces is of fundamental importance in physics, biology, and chemistry. Liquid cell transmission electron microscopy (LCTEM) is a promising technique for studying motion of nanoparticles with high spatial resolution. Yet, the lack of understanding of how the electron beam of the microscope affects the particle motion has held back advancement in using LCTEM for in situ single nanoparticle and macromolecule tracking at interfaces. Here, we experimentally studied the motion of a model system of gold nanoparticles dispersed in water and moving adjacent to the silicon nitride membrane of a commercial LC in a broad range of electron beam dose rates. We find that the nanoparticles exhibit anomalous diffusive behavior modulated by the electron beam dose rate. We characterized the anomalous diffusion of nanoparticles in LCTEM using a convolutional deep neural-network model and canonical statistical tests. The results demonstrate that the nanoparticle motion is governed by fractional Brownian motion at low dose rates, resembling diffusion in a viscoelastic medium, and continuous-time random walk at high dose rates, resembling diffusion on an energy landscape with pinning sites. Both behaviors can be explained by the presence of silanol molecular species on the surface of the silicon nitride membrane and the ionic species in solution formed by radiolysis of water in presence of the electron beam.

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Yamaguchi, Akinobu, Takao Fukuoka, Iukuo Okada, Mari Ishihara, Ikuya Sakurai et Yuichi Utsumi. « Caltrop particles synthesized by photochemical reaction induced by X-ray radiolysis ». Journal of Synchrotron Radiation 24, n^o 3 (20 mars 2017) : 653–60. http://dx.doi.org/10.1107/s1600577517002314.

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X-ray radiolysis of a Cu(CH3COO)2 solution was observed to produce caltrop-shaped particles of cupric oxide (CuO, Cu2O), which were characterized using high-resolution scanning electron microscopy and micro-Raman spectrometry. X-ray irradiation from a synchrotron source drove the room-temperature synthesis of submicrometer- and micrometer-scale cupric oxide caltrop particles from an aqueous Cu(CH3COO)2 solution spiked with ethanol. The size of the caltrop particles depended on the ratio of ethanol in the stock solution and the surface of the substrate. The results indicated that there were several synthetic routes to obtain caltrop particles, each associated with electron donation. The technique of X-ray irradiation enables the rapid synthesis of caltrop cupric oxide particles compared with conventional synthetic methods.

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Ismayilova, M. K., I. I. Mustafayev, S. Z. Melikova, F. N. Nurmammadova et M. H. Aliyeva. « Radiation-induced isomerization reaction mechanism of hydrocarbons on the surface of solid acid ». Physics and Chemistry of Solid State 24, n^o 3 (13 septembre 2023) : 460–66. http://dx.doi.org/10.15330/pcss.24.3.460-466.

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This paper's goal is to investigate how petroleum's n-alkane isomerization reaction occurs on the surface of a solid nanocatalyst. In this experiment, the isomerization of aromatic-rich crude oil is being studied as a result of radiation exposure. It was discovered that sodium-rich bentonite –solid acid, from the Alpoid deposit works well as a catalyst for refining petroleum. Possible mechanisms of the radio-catalytic reaction that converts n-alkanes to branched hydrocarbons have been researched by methods of FT- IR spectroscopy and gas chromatography. The effect of acidity type of the nanostructured bentonite clay on Lewis acid cites is proposed to explain observed results. Additional radiation energy, which is mainly generated due to the nanobentonite volume, results in a more efficient aromatic- rich petroleum radiolysis process. Also, it was investigated the dynamics of dose –dependent changes in the amount of branched hydrocarbons. One of the primary objectives of this research work is increasing the efficiency of transformation of adsorbed beam energy in solid phase to the system and improvement of hydrocarbon isomerization reactions in crude oil. The results of hydrocarbon transformations are discussed in terms of the behavior of excited electrons in solids. Novel eco-friendly nanocatalyst creates new opportunities for hydrocarbons with multi- branched structures.

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Sheehan, John G. « Electron-beam radiation damage to cellulose fibers in ESEM ». Proceedings, annual meeting, Electron Microscopy Society of America 49 (août 1991) : 1130–31. http://dx.doi.org/10.1017/s0424820100089962.

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Of interest to the paper industry is how cellulose fibers shrink, swell, and break during wetting and drying of paper. The Environmental Scanning Electron Microscope (ESEM) is a new tool for examining wetting and drying. However, surfaces of cellulose fibers appeared smoothed in an unexpected way while examined in the ESEM (made by Electroscan, Wilmington, MA, USA) during wetting and drying. Closer examination revealed that the smoothed appearance was due to electron beam radiation damage that occurs while the fibers are wet. Shown below is evidence that damage to wet cellulose fibers is due to attack from free radicals that are products of radiolysis of ice.

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