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Effect of laser radiation on the gamma activity of aqueous salt solutions containing <sup>152</sup> Eu
摘要： We report an experimental study of the effect of laser irradiation of aqueous salt solutions containing the 152Eu isotope in the presence of nickel nanoparticles on the gamma activity of the isotope. Nickel nanoparticles are generated using laser ablation of the target in water and added to the radionuclide solution before irradiation. Two types of Nd : YAG lasers with a pulse duration of 10 ns and different repetition rates are used to irradiate the solutions. It is found that the 152Eu activity as a result of repeated irradiation of solutions by a series of pulses decreases with each irradiation cycle. The obtained results are compared with data on the effect of maser radiation with a wavelength of 8 mm on the activity of the same isotope. Possible mechanisms of the effect of electromagnetic radiation on the 152Eu gamma activity are discussed.
关键词： laser radiation,nanoparticle solutions,gamma activity of isotopes
更新于2025-09-16 10:30:52
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Influence of laser radiation on processes of electrochemical phytoremediation of copper from waste water by eichhornia
摘要： The plant cell, a natural bioelectrochemical membrane reactor, is able to extract and utilize efficiently various contaminants, including heavy metals (TM). The method does not require expensive equipment and reagents, and there is no secondary water contamination, as the sorbent is natural biological material - higher aquatic plants. The costs of phytoradiation technologies do not exceed 20% of alternative methods with an average purification efficiency of 60-80%. The work done to increase the efficiency of purification by stimulating the phytoremediation process by the influence of physical factors: magnetic field, weak electric current, infrared and ultraviolet radiation gave a positive result [1-4]. The purpose of this work was to study the effect of laser influence on the process of copper ions extraction from sewage with the help of a higher aquatic plant - eichhornia.
关键词： eichhornia,laser radiation,waste water,phytoremediation,copper
更新于2025-09-16 10:30:52
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Laser-Induced-Electro-Explosion Synthesis of Powder Materials (LIEES)
摘要： In this paper, a method for the synthesis of microspheres containing titanium carbide by laser radiation is described. The formation of microspheres is carried out by the action of femtosecond laser radiation on the surface of titanium in the reaction medium - the saturated hydrocarbon. Hexane was used as a hydrocarbon. The obtained microspheres have an average size of 1-3 μm and can be used in applications of additive engineering, powder metallurgy as the main raw material, or as an alloying additive. To increase the efficiency of particle output, a method of laser action combining with electric current is proposed. The behavior of an electric discharge in the plasma channel area was studied.
关键词： laser radiation,metal powders,femtosecond pulses,ablation in a liquid,plasma channel
更新于2025-09-16 10:30:52
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Hydrodynamic modeling and time-resolved imaging reflectometry of the ultrafast laser-induced ablation of a thin gold film
摘要： The ablation of thin metal films using ultrafast laser radiation represents a standard processing procedure in laser technology. However, looking closer to the resulting structures, the arising topology deviates strongly from the expected one. Ablation of thin gold films using ultrafast laser radiation with a Gaussian-shaped spatial intensity distribution results in flat topologies. By synergistically combining space and time-resolved reflectometry with expanded two-temperature hydrodynamic modeling, we explain the formation of bulging and rupture of the thin film-surface by the expansion of strongly stretched liquid material due to the induced rarefaction wave propagating towards the substrate. Also, the formation of a flat ablation structure is described by the interplay of two rarefaction waves, one propagating towards the substrate and the other one propagating towards the vacuum boundary, within the completely molten film. The simulated topology agrees excellent with the experimentally observed ablation structure. Besides, all simulated stages of excitation of the gold film, namely electron-phonon non-equilibrium, hydrodynamic expansion, and rupture, are confirmed by space and time-resolved pump-probe reflectometry.
关键词： Imaging reflectometry,Thin film ablation,Femtosecond laser radiation,Two temperature model hydrodynamics (TTMHD),Gold thin film,Ultrafast metrology
更新于2025-09-16 10:30:52
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Method for measuring main characteristics of electron-optical cameras
摘要： A procedure is described for determining the basic parameters of linear-sweep electron-optical cameras. The techniques are considered for measuring the limiting temporal resolution and dynamic range of the PS-1/S1 camera using a femtosecond laser and sinusoidal-modulated laser radiation.
关键词： temporal resolution,electron-optical camera,dynamic range,picosecond – femtosecond laser radiation
更新于2025-09-16 10:30:52
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Laser radiation impact on a solid surface and formation of micro- and nanostructures
摘要： The work is devoted to the problem of micro- and nanostructuring of the surface of solids as a result of exposure to laser radiation. The method of forming periodic surface structures by means of femtosecond laser processing is presented using the example of solving the problem of titanium structuring.
关键词： femtosecond laser processing,micro- and nanostructures,laser radiation,titanium structuring
更新于2025-09-12 10:27:22
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[IEEE 2019 Joint Conference of the IEEE International Frequency Control Symposium anEuropean Frequency and Time Forum (EFTF/IFC) - Orlando, FL, USA (2019.4.14-2019.4.18)] 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum (EFTF/IFC) - Laser Treatment of Quartz Crystal Blanks for the Modification of Properties of Resonators
摘要： It is known that quartz crystal blanks have to go through many procedures of mechanical processing for the exact configuration to ensure precise geometry for expected involving mechanical performance. processing are widely used for the shaping and reduction in sizes could be done with laser beams to satisfy the objectives. Given the fact laser beams can be speedy and cleaner in the process, it is imaginable that some mechanical processing procedures can be replaced by laser radiation or other energy methods at a lower cost. To this goal, we use laser with different strengths and durations to scan the selected surface areas of blanks of quartz crystal to change the property of exposed portions with noticeable changes. After validation of the laser processing, we started scanning quartz crystal blanks of resonators for improvements. The experiments showed that with properly designed radiation pattern and areas, we should be able to use the laser treatment as part of the manufacturing process to innovate the existing process and products.
关键词： Quartz,Laser,Radiation,Resonator,Ablation
更新于2025-09-12 10:27:22
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Excitation of Low-Frequency Surface Modes in the Plasma Layer Under the Action of Two-Frequency Laser Radiation
摘要： We construct the theory of generation of low-frequency surface eigenmodes in a rare?ed plasma layer under the action of two-frequency laser radiation. We show that a signi?cant increase in the energy of the plasma-layer low-frequency eigenmode occurs under resonance conditions, where the frequency of the mode coincides with the di?erence in laser frequencies. We establish that under the resonance conditions the energy ?ux density carried by the low-frequency eigenmode can be comparable to the laser-radiation intensity.
关键词： plasma layer,terahertz frequency range,two-frequency laser radiation,low-frequency surface eigenmode
更新于2025-09-12 10:27:22
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Optimization of endovenous laser coagulation: in vivo experiments
摘要： Finding optimal parameters of endovenous laser coagulation using the radiation with a wavelength of 1910 nm. In vivo experiments have been carried out on the small saphenous veins of three sheep of Edilbay breed and the dependence of venous wall and surrounding tissue damage on the radiation power was analyzed on the basis of morphological study results, as well as ultrasound examination and clinical observation of animals in the postoperative period. As radiation source, we used the diode-pumped solid-state laser, based on the LiYF4:Tm crystal, with emission wavelength of 1910 nm. For morphological study, veins were harvested immediately and 40 days after operation. Histological analysis of the vein after treatment with 1.5-W radiation revealed asymmetric wall injury and a thrombus formation in the lumen. The blood thrombus formation and pronounced vein wall damage was observed after treatment with 3-W radiation. Perivenous tissue injury is insignificant and does not lead to postoperative complications as in the case of using 1.5-W radiation. Increasing the radiation power to 4 W results in the total vein wall destruction and the thrombus formation, which persists for 40 days after the procedure. Based on the results of clinical observations of animals with registration of skin wound healing, as well as the results of histological examination of veins harvested immediately after the EVLC and 40 days after, it was concluded that the laser power value of 3–4 W can be recommended for use in the clinic.
关键词： Histologic analysis,Endovenous coagulation,Laser radiation
更新于2025-09-12 10:27:22
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Electronically controlled generation of laser pulse patterns in a synchronously pumped mode-locked semiconductor optical amplifier-fiber laser
摘要： A method for electronically controlled formation of user-defined laser pulse patterns in a synchronously pumped laser based on a semiconductor optical amplifier and an all-fiber resonator is proposed and investigated. It is demonstrated that synchronous pumping allows mode-locked operation with the laser radiation structured as an arbitrary pulse pattern repeatable on each cavity round trip. Direct electronic control of the structure and shape of the generated laser pulse patterns is implemented. The accuracy of the reproduction of modulation pulse patterns and waveforms delivered from a radiofrequency arbitrary waveform generator is examined. The time constraint on the pulse pattern formation in the steady-state mode-locked lasing regime is revealed, as well as the feasibility of the quasi-steady-state regime with on-the-lasing continuous modification of the pulse pattern structure.
关键词： mode locking,fibre lasers,laser radiation characteristics
更新于2025-09-12 10:27:22