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Calibration-free elemental analysis combined with high repetition rate laser-ablation spark-induced breakdown spectroscopy
摘要： Calibration-free (CF) method combined with high repetition rate laser-ablation spark-induced breakdown spectroscopy (HRR LA-SIBS) was ?rst utilized to realize elemental analysis of alloy samples. A compact ?ber laser operated at 30 kHz pulse repetition rate was used to ablate the sample and the spectra were recorded with a compact ?ber spectrometer in non-gated signal recording mode. Three standard aluminum alloy samples were analyzed to evaluate the performance of this technique. Median ?ltering method was applied to reduce the contribution of the continuum background to the intensity of the atomic lines. The averaged electron density was determined to be (2.36–2.49) × 1017 cm?3 according to the Stark broadening of four ionic lines. 11,800 K averaged plasma temperature was estimated from the Saha-Boltzmann plots. The plasma could be veri?ed to be in a state close to local thermodynamic equilibrium. The analytical error was < 0.5% for the major element and < 35% for minor elements with > 0.1% concentrations. It was demonstrated that CF method combined with HRR LA-SIBS was possible to realize reliable quantitative elemental analysis for aluminum alloy samples.
关键词： Calibration-free,Laser-ablation spark-induced breakdown spectroscopy,Elemental analysis,Aluminum alloy,High repetition rate
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019 - Tomsk, Russia (1–5 October 2019)] PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019 - Cutting of aluminum alloys with a Q-switched repetitively pulsed CO2 laser under conditions of intense material evaporation
摘要： The results of an experimental study of laser cutting of aluminum-lithium alloys using a repetitively pulsed CO2 laser with Q-switching under conditions of intense material evaporation are presented. The dependence of cut quality on the assisted gas pressure is determined. It is shown that a high-quality cut with a sheet thickness of 1.5 mm can be obtained at a gas pressure of 0.5–0.6 bar, which is significantly less compared to cutting with a continuous laser power. This makes it possible to reduce the assisted gas consumption. The dependence of cut surface roughness on the pulse repetition rate is measured.
关键词： laser cutting,aluminum-lithium alloys,material evaporation,Q-switched CO2 laser,cut quality,pulse repetition rate,gas pressure
更新于2025-09-16 10:30:52
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Influence of exciton energy on intersubband transition of chirped superlattice GaAs/AlGaAs quantum cascade laser
摘要： The influence of exciton energy on intersubband transition was simulated for a chirped supperlattice quantum cascade laser of GaAs/AlxGa1-xAs. Exciton energy was modelled as a function of QW width for alloys of various percentages of constituent elements. The results showed that the exciton energy decreased proportionally with increasing QW width. Models were also generated to study exciton energy as a function of the percent alloy contents of AlxGa1-xAs barriers for QWs of various widths. Exciton energy showed characteristics of higher discrete energy when QW width was narrower. Transition energy was also simulated from 1e and 2e to the 1s exciton state as functions of applied electric field at various QW widths. Our simulation results showed that the transition energy from 2e to the 1s exciton state increased proportionally to the increasing strength of the electric field. This transition energy was indicative of THz range radiation.
关键词： percent alloy contents,chirped superlattice quantum cascade laser,aluminum arsenide monolayer,THz radiation,transition energy
更新于2025-09-16 10:30:52
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Effect of the Density of PETN-Aluminum Composites on the Threshold of Laser Initiated Explosive Decomposition
摘要： The results of studying the laser induced explosive decomposition thresholds of PETN–aluminum composites depending on the concentration of inclusions at various sample densities are presented. An increase in the density of the samples reduces the minimum critical energy density of explosive decomposition and the concentration of inclusions at which explosions are observed.
关键词： laser initiation,PETN,aluminum nanoparticles,gas-dynamic unloading,explosion
更新于2025-09-16 10:30:52
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Numerical simulation and experimental validation of a photovoltaic/thermal system based on a roll-bond aluminum collector
摘要： In this paper, the performance of a polycrystalline silicon photovoltaic module and photovoltaic/thermal module are experimentally investigated under outdoor conditions, using a roll-bond thermal collector attached on the backside of the photovoltaic module. Furthermore, the temperature, pressure and velocity distributions across the photovoltaic/thermal module are simulated using a steady state thermal model. Compared with the photovoltaic module, the performances of photovoltaic/thermal module with and without the coolant circulation are both examined using a water volume of 100 L and a coolant mass ?ow rate of 0.034 kg/s. Using a design with a timed supplement water strategy, the electrical energy produced by the photovoltaic/thermal system has been increased by 3.25%. Compared without supplement before, the electrical energy can be extra increased more than 1%. A good agreement is found between simulated and experimental results. There is no doubt that the output performance of the photovoltaic/thermal system can be improved effectively by the design of timed supplement water.
关键词： Performance,Roll-bond design,Aluminum collector,Supplemental water strategy,Photovoltaic/thermal system
更新于2025-09-16 10:30:52
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Correlation of Process Parameters and Porosity in Laser Welding of 7A52 Aluminum Alloy using Response Surface Methodology
摘要： The article presents an experimental investigation of the effect of process parameters (i.e. laser power, welding speed and defocus distance) on porosity in laser welding of 7A52 aluminum alloy. A three-factor, three-level factorial Box–Behnken design (BBD) of response surface methodology (RSM) was used to complete the design matrix with the objective of optimizing the process parameters. Multiple regression models were established to predict the correlation between the selected process parameters and porosity, and then were tested for adequacy using analysis of variance (ANOVA). The results showed that macro pores in laser welding seam were mainly keyhole induced, and porosity susceptibility was mostly dominated by welding speed. The optimal combination of process parameters is the laser power of 3.5kW, welding speed of 10.0mm/s, and the defocus distance of +4.0mm. Under the optimal process parameters, superior weld seams without macro pore were produced. The predicted porosity area fraction with RSM models was confirmed to be in good agreement with the measured values of validation experiments.
关键词： process parameter,response surface methodology,porosity,7A52 aluminum alloy,laser welding
更新于2025-09-16 10:30:52
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Application of acoustic emission and laser optoacoustics at various stages of defect formation during friction stir welding
摘要： This paper covers basic aspects of laser ultrasound and acoustic emission non-destructive testing methods in application of monitoring friction stir welds during its deformation and fracture. Stress-strain curves for such welds were obtained and the mechanical characteristics of welded joints of aluminum-magnesium alloy were determined. Using acoustic elastic effect levels of mechanical stresses were measured. Signals of acoustic emission, stimulated by one-axis loading, were registered and analyzed. It was established that acoustic emission during deformation and fracture of samples of welded joints is associated with the course of the process of plastic flow of the material. The nature of the distribution of acoustic emission parameters in the destruction of welded joints with defects has distinctive features. In conditions of one axis quasi static loading rate event count acoustic emission is the most informative parameter.
关键词： friction stir welding,laser optoacoustics,aluminum-magnesium alloy,acoustic emission,defect formation
更新于2025-09-16 10:30:52
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[Laser Institute of America ICALEO? 2017: 36th International Congress on Applications of Lasers & Electro-Optics - Atlanta, Georgia, USA (October 22–26, 2017)] International Congress on Applications of Lasers & Electro-Optics - Spatial beam modulation to reduce electrical resistance in laser welded aluminum to copper dissimilar joints
摘要： Laser welding of pure aluminum (Al99.5) to pure copper (Cu-OF) in overlap configuration was investigated. Spatial modulation of the laser beam perpendicular to the welding direction was applied with frequencies of up to 1 kHz and amplitudes of up to 1 mm. The mixing behavior, seam geometry, and averaged copper content of the welds could be controlled by the application of the spatial modulation of the laser beam. This allowed to produce aluminum to copper dissimilar welds with low electrical resistances of down to 1 μ?.
关键词： copper,aluminum,laser welding,electrical resistance,spatial beam modulation
更新于2025-09-16 10:30:52
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Development of aluminum paste with/without boron content for crystalline silicon solar cells
摘要： Improvement of aluminum alloyed p?+?back surface ?elds (p?+?BSF) which is an essential requirement for achieving high ef?ciency silicon solar cells has been an important task. One of the ways to have better quality BSFs can be to introduce screen printable aluminum pastes with boron content. Two type of pastes were developed in this work and recipes were provided in detail: screen-printable aluminum paste without boron content (B-free-Al-paste), screen-printable aluminum paste with boron content (Al-B-paste). The ingredients of the pastes were optimized and basically evaluated in terms of alloying and impurity characteristics by measurement of sheet resistances, carrier lifetimes and SIMS analysis. Carrier lifetimes of the wafers processed by Al-B-paste maintained at around 300 μs relatively higher than the wafers processed by B-free-Al-paste. P-type silicon solar cells were fabricated using developed pastes and were compared with those of the cells fabricated by commercial aluminum pastes. Best ef?ciency of 17.8% was achieved with totally vacuum-less cell production process and Suns-Voc analysis were also carried out for fabricated solar cells.
关键词： silicon solar cell,boron doping,aluminum paste
更新于2025-09-16 10:30:52
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Highly efficient flexible organic light-emitting diodes based on a high-temperature durable mica substrate
摘要： Muscovite mica is expected to show great potential in flexible optoelectronics due to its superb temperature tolerance, high transmittance, chemical stability, and mechanical durability. This flexible substrate produces sputtered transparent conducting electrodes (TCEs) with excellent film quality with high transmittance and conductivity. In this study, a designed composite TCE consisting of aluminum-doped zinc oxide (AZO) and indium tin oxide (ITO) is proposed to simultaneously maximize flexibility and conductivity. Blue-, green-, and red-emitting flexible organic light-emitting diodes (FOLEDs) using composite TCEs on mica exhibited satisfactory performance with maximum respective electroluminescence efficiencies of 18.1% (38.7 cd/A), 18.7% (66.2 cd/A), and 13.3% (22.2 cd/A). Furthermore, the green-emitting FOLEDs were modified to construct tandem FOLEDs, giving a higher peak efficiency of 27.9% (93.3 cd/A) and saturated green emission. These results can serve as a useful reference for future work on composite TCEs on mica for FOLEDs in display and lighting applications.
关键词： Organic light-emitting diodes (OLEDs),Flexible,Tandem,Indium tin oxide (ITO),Muscovite mica,Aluminum-doped zinc oxide (AZO)
更新于2025-09-16 10:30:52