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Laser-based surface pre-treatment for metal-plastic hybrids using a new process strategy
摘要： In order to join metal-plastic hybrid parts so as to achieve lightweight constructions, innovative joining technologies are essential. For this, thermal joining is a promising approach due to the absence of any joining agent. The joint strength can be increased by surface pre-treatment of the metal with continuous wave laser radiation. Large joining areas, however, are challenging in terms of productivity, efficiency and geometrical flexibility when beam trajectories, which can be easily combined with on-the-fly processing. More precisely, a load direction, and causes lower thermal distortion of the metal sheet than using conventional processing of large areas. In this context, the resulting topography of the metal was analyzed circularly oscillating laser focal spot is geometrically independent of every possible in-plane with respect to the surface roughness and a design criterion was mathematically derived and experimentally validated. Additionally, the joint strength was compared to the strength using conventional beam trajectories. A more promising approach is the use of continuous with a carbon-fiber-reinforced thermoset. The laser-based pre-treatment using the circularly oscillating laser focal spot led to a similar joint strength, while being more productive when resulting from conventional beam trajectories. For verification, steel substrates were joined combined with on-the-fly processing, compared to conventional structuring trajectories.
关键词： surface pre-treatment,continuous wave laser radiation,metal-plastic hybrids,thermal joining
更新于2025-09-23 15:19:57
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Kinetic modeling of spatio-temporal evolution of the gain in copper vapor active media
摘要： This paper addresses the theoretical study of the spatio-temporal gain profile of the copper vapor active media. The description of a kinetic model of a copper vapor amplifier which allows us to study spatio-temporal evolution of the amplifying characteristics is described. Using the kinetic model time and radial evolution of the medium optical gain and factors which governs the radial gain profile inhomogeneity of the brightness amplifier are shown.
关键词： brightness amplifier,laser radiation,laser monitor,beam profile,kinetic model,active optical system
更新于2025-09-19 17:15:36
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Incorporation in Lipid Microparticles of Acid Red 87, a Colourant Used in Tattoo Inks: Effect on Photodegradation Under Simulated Sunlight and Laser Radiation
摘要： Tattoo colourants decompose under solar radiation and when exposed to laser light for their removal, leading to the accumulation in the dermis of toxic products. Aim of this study was to develop lipid microparticles (LMs) loaded with the colourant, Acid Red 87 (C.I. 45380) used in tattoo inks, and to investigate the effect of this system on the photostability of the colourant under simulated sunlight or laser irradiation. LMs loaded with C.I. 45380 were prepared by melt emulsification using tristearin and phosphatidylcholine as excipients. They were characterized by optical microscopy, laser diffraction, X-ray diffraction and release studies. Free C.I. 45380 and the colourant-loaded LMs were irradiated with a solar simulator or a Q-switched laser. Irradiation with a solar simulator demonstrated that photodecomposition of C.I. 45380 was markedly reduced by incorporation of the dye in the LMs, from 20.5 ± 4.6% to 1.3 ± 1.8%. Conversely, the laser-induced degradation of the colourant (30.1 ± 6.6%) was not significantly influenced by encapsulation in the LMs (the encapsulated C.I. 45380 loss was 27.4 ± 5.5%). Incorporation of C.I. 45380 in lipid microparticles enhances the photostability under sunlight of tattoo inks containing this colourant, without affecting its laser-induced degradation and hence laser removal efficiency.
关键词： photodegradation,Acid Red 87,tattoo colourants,laser radiation,lipid microparticles
更新于2025-09-19 17:13:59
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PFI-ZEKE-photoelectron spectroscopy of N <sub/>2</sub> O using narrow-band VUV laser radiation generated by four-wave mixing in Ar using a KBBF crystal
摘要： A new nonlinear optical scheme relying on sum-frequency mixing in a KBe2BO3F2 crystal has been used to generate intense, broadly tunable, narrow-bandwidth, coherent vacuum-ultraviolet (VUV) radiation beyond 16 eV by resonance-enhanced four-wave mixing in Ar. The VUV radiation was used to record high-resolution pulsed-field-ionization zero-kinetic-energy photoelectron spectra of the N2O+ A+ ← N2O X photoionizing transition in the wave-number range from 132 000 cm?1 to 135 000 cm?1. The rotational structure of almost all vibrational levels of the A+ state with vibrational term values up to 2700 cm?1 could be resolved, and improved values of the first two adiabatic ionization energies of N2O, corresponding to the formation of the X+ 2Π3/2(000) J+ = 3/2 and A+ 2Σ+(000) N+ = 0 levels of N2O+ from the X 1Σ+(000) J′′ = 0 ground state [103 969.30(12) cm?1 and 132 197.70(12) cm?1, respectively], were derived. The rotational intensity distributions of the bands were found to depend strongly on the value of the vibrational angular momentum of the ionic levels. The vibrational structure is discussed in terms of previously reported effective-Hamiltonian analyses.
关键词： KBBF crystal,PFI-ZEKE-photoelectron spectroscopy,N2O,narrow-band VUV laser radiation,four-wave mixing
更新于2025-09-19 17:13:59
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Method of Laser Thermal Image Spectroscopy for Surface Diagnostics
摘要： A new method of laser-thermal imaging spectroscopy is presented and the results of studying samples with different absorption coefficients are reported. The times required for heating the surface of these samples by laser radiation with a wavelength of 0.634 μm to a temperature exceeding the initial value by 0.3°C are calculated and compared with the experimental data. The depths of laser-radiation penetration into the surface layer of the material under the condition of external and internal reflection are calculated. The depth determines the transition region in which the energy of absorbed laser radiation transforms into the thermal energy of the substance. It is shown that the method allows the surface of materials to be studied and zones with different optical and physical-chemical properties to be studied. The method can be used to solve problems in the field of medicine, surface restoration, forensic examination and others.
关键词： defect substance,surface defects,surface heating time,spectral absorption coefficient,penetration depth of laser radiation
更新于2025-09-19 17:13:59
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Effect of low-intensity laser radiation on hemostasis in patients with chronic obstructive pulmonary disease
摘要： Objective. The study presents results of the low-intensity intravenous (IV) laser radiation effect on some indicators of the hemostasis system and respiratory function of 83 patients with a chronic lung disease (COPD), stable phase, II-III (after GOLD scale), including 51 men and 32 women. The average COPD duration was 9.6±4.4 years. Materials and methods. All patients with COPD were randomly divided into 2 groups - comparison (30 people) and main (53 people). The control group consisted of 20 practically healthy people, matched by sex and age. Patients in the control group received only standard drug therapy with IGCC/DBA combination (budesonide/formoterol, salmeterol/fluticasone propionate inhalation at a therapeutic dose corresponding to the COPD clinical symptoms severity). Result and Discussion. In addition to the basic treatment, the main group received a course of intravenous low-intensity laser radiation. As established before the treatment initiation, patients with COPD experienced a decrease in FEV1, Tiffno index, SaO2. Conclusion. The respiratory function disruption was accompanied by a significant activation of plasma hemostasis (prothrombin time shortening, thrombin time, activated partial thromboplastin time) and a significant increase in platelet aggregation (increase in the aggregation degree, aggregation rate, decrease in the aggregation time). At the same time, in patients with COPD, a significant decrease in anticoagulant activity was observed before treatment, particularly antithrombin III decrease when compared with the control group (p <0.05) and CRP (main group: 0.86±0.02; control group: 0.85±0.02). The introduction of low-intensity laser radiation into the patients complex with COPD led to the these parameters normalization.
关键词： platelet aggregation,low-intensity intravenous laser radiation,COPD,plasma hemostasis
更新于2025-09-19 17:13:59
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[IEEE 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus) - St. Petersburg and Moscow, Russia (2020.1.27-2020.1.30)] 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus) - Study of Long-term Pulsed Laser Irradiation Effect on SWCNT-Water Dispersion
摘要： In this paper, we studied the effect of long-term pulsed laser radiation from visible range on an aqueous dispersion with single-walled carbon nanotubes with a concentration of 0.005%. The dependence of the normalized temperature dependence, and transmission on nonlinear optical characteristics were determined. In several minutes of irradiation, bubbles appeared in the dispersion and enlightenment was observed, i.e. increase in transmission. It was determined that an aqueous dispersion with carbon nanotubes retains its optical characteristics for 600 pulses at a laser pulses frequency of 10 Hz and power of 230 mW.
关键词： carbon nanotubes,thermograms,pulsed laser radiation,nonlinear optical properties,optical limiters
更新于2025-09-19 17:13:59
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Material Reuse in Laser Powder Bed Fusion: Side Effects of the Lasera??Metal Powder Interaction
摘要： Metal additive manufacturing is changing the way in which engineers and designers model the production of three-dimensional (3D) objects, with rapid growth seen in recent years. Laser powder bed fusion (LPBF) is the most used metal additive manufacturing technique, and it is based on the efficient interaction between a high-energy laser and a metal powder feedstock. To make LPBF more cost-efficient and environmentally friendly, it is of paramount importance to recycle (reuse) the unfused powder from a build job. However, since the laser–powder interaction involves complex physics phenomena and generates by-products which might affect the integrity of the feedstock and the final build part, a better understanding of the overall process should be attained. The present review paper is focused on the clarification of the interaction between laser and metal powder, with a strong focus on its side effects.
关键词： metal powder,condensate,spatter,LPBF,laser radiation
更新于2025-09-19 17:13:59
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Study of the phase composition and tribological properties of carbon tool steels after laser surface hardening by quasi - CW fiber laser
摘要： The paper contains the investigation results on the structure and phase composition of the laser radiation area (LRA) of the U8 and U10 steels over its entire thickness. In the present study, the laser surface hardening of both U8 (ASTM - W1-7) and U10 (ASTM - W1-9) steels in the air was performed by exploiting a quasi - CW fiber laser with a 130 W power and 3 mm/s processing speed. The phase composition of the oxide layer formed as a result of laser treatment (LT) in air, as well as the structure of the oxide-metal interface on the surface of U8 (ASTM–W1-7) and U10 (ASTM–W1-9) carbon tool steels were studied by X-ray photoelectron spectroscopy (XPS). It was established that the thickness of the completely oxidized surface layers for U8 and U10 steels is 38.7 nm and 99 nm, respectively. The composition of the oxides of the steel surface after LT was determined. The presence of a wüstite-based film on U8 steel evidences the low wear properties of the LRA surface, while the thicker oxide layer of the modified U10 steel which contains Fe2O3 and Fe3O4 oxides with better strength properties, on the contrary, provides U10 steel surface with higher wear resistance. It was found that the wear rate of U10 steel modified surface decreases by more than two times, while the given value for U8 steel reduces no more than 17%. The paper reports the metallographic examination of the LRA structure. It was shown that the wear-resistant structural components that appeared after laser treatment lead to an increase in the deformation properties of steels. The maximum microhardness value of the LRA is 710 HV0.1 for U8 steel and 750 HV0.1for U10 steel.
关键词： Laser radiation,Oxidized surface layers,X-ray photoelectron spectroscopy,Phase composition,Surface finishing treatment,Elemental composition
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - St. Petersburg, Russia (2019.10.17-2019.10.18)] 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Laser ranging of the Atmospheric Aerosol and Determination of its Disperse Composition
摘要： It has been fulfilled the assessment of the differential easing method for the remote measurement of the aerosol pollution disperse composition parameters in the atmospheric boundary layer over the industrial enterprise. Laser attenuation signals at three wavelengths have been measured using the developed aerosol lidar system, from which average values of the volume and surface diameter of aerosol particles of cement have been obtained. The diameter average value of 0.61±0.04 μm and relative accuracy ε=11% have been calculated.
关键词： differential easing and scattering,aerosol lidar,laser radiation,particles average volume and superficial diameter
更新于2025-09-19 17:13:59