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Synthesis and Luminescence properties of Lithium Aluminium Phosphate Glasses Doped with Nd <sup>3+</sup> Ion for Laser Medium
摘要： Nd3+ ion doped lithium aluminium phosphate glasses were synthesized and studied their properties for laser medium application. The density and the refractive index of the glass samples were carried out at the room temperature. The optical and luminescence properties were studied by investigating absorption and NIR emission spectra of the glass samples. The glasses absorbed photons in ultraviolet (UV), visible light (VIS) and near-infrared (NIR) regions are clearly observed from absorption spectra. For the photoluminescence properties, the glass samples showed the strongest emission at 1063 nm when it were excited by 581 nm which assigned to the energy transitions of Nd3+. The three phenomenological Judd-Ofelt parameters (?2, ?4, ?6) were determined from the spectral intensities of absorption band in order to calculate the radiative transition possibility (AR), stimulated emission cross section (σ(?p)) and branching ratio (?R) of the 4F3/2?4I9/2, 4I11/2 and 4I13/2 transitions. From the obtained results the conclusions made about the possibility of using these glasses as laser material.
关键词： luminescence properties,laser medium,lithium aluminium phosphate glasses,Nd3+ ion,Judd-Ofelt parameters
更新于2025-09-19 17:13:59
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Vertically Aligned Al-Doped ZnO Nanowire Arrays as Efficient Photoanode for Dye-Sensitized Solar Cells
摘要： In this communication, we report on the synthesis of vertically aligned aluminium (Al)-doped ZnO (ZnO:Al) nanowire (NW) thin films on FTO-coated glass substrates and their use as photoanode in dye-sensitized solar cells (DSSC). Very thin Al layers (≈3 nm, ≈6 nm and ≈10 nm) were deposited onto chemically synthesized ZnO nanowire film by electron-beam evaporation. The films were then subjected to rapid thermal annealing to incorporate different amounts of Al (≈0.98 at.%, 1.94 at.% and ≈2.89 at.%) into the ZnO nanowires. Optical, microstructural and compositional study of the films confirmed the growth of highly transparent and well-aligned ZnO:Al nanowires with a hexagonal crystal structure. The basic DSSC structure was fabricated using both undoped ZnO nanowire and ZnO:Al nanowire thin films as photoanode. In both cases, commercially available N3 dye was used as a photosensitizer, iodide/tri-iodide solution as electrolyte and FTO-coated glass as counter electrode. A significant increase in short-circuit current was observed, from 1.3 mA cm?2 for the pristine ZnO nanowire film-based DSSC to 4.4 mA cm?2 for the ZnO:Al (2.89 at.%) nanowire film-based DSSC. The overall power conversion efficiency (PCE) was also found to increase from 0.13% (for pristine ZnO nanowire thin film) to 0.49% for the ZnO:Al thin film-based DSSC.
关键词： thin film,DSSC,aluminium,ZnO nanowires
更新于2025-09-19 17:13:59
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High Power Fiber Laser Welding with Filler Material
摘要： Industry today is continually challenged to improve quality, reliability, reduced cycle times, and improve the overall manufacturing efficiency. This is driving manufacturers across various market sectors to consider fiber laser welding and the possibility to automate their welding processes to improve consistency and part quality. Another driver is the changing workforce dynamics. It is hard to find or train skilled workers who can consistently and reliably weld aluminum, titanium, and high-strength nickel alloys. This is particularly true when welding with filler material where the base materials are subject to porosity and cracking during the welding process.
关键词： Fiber Laser Welding,Titanium,Filler Material,Nickel Alloys,Aluminium,Laser Welding
更新于2025-09-19 17:13:59
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SPR responsive xylenol orange functionalized gold nanoparticles- optical sensor for estimation of Al3+ in water
摘要： Xylenol orange functionalized gold nanoparticles (XO-AuNPs), prepared by reducing HAuCl4 in presence of xylenol orange were found to be selective and sensitive for optical sensing of Al3+ in water. XO-AuNPs nanoparticles were characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS); the nanoparticles formed were of spherical shape and of uniform size of 3-12 nm. The interaction between Al3+ and XO-AuNPs at pH ~3 was studied by XPS analysis. XPS and TEM studies revealed that aggregation of XO-AuNPs in the presence of Al3+ takes place through analyte induced cross-linkage mechanism. Al3+ induced selective aggregation of the XO-AuNPs lead to a visual change in color of the colloidal solution from deep red to blue. The changes in characteristic absorption peak of XO-AuNPs were monitored; the ratio of A550nm/A515nm was used to quantify the concentration of Al3+ in water samples. The method gave a linear response from 50?300 ppb (R2 = 0.985) of Al3+ in drinking water with a detection limit of 12 ppb. The proposed method did not suffer any major interference from concomitant transition metal ions and anions. The developed method was simple, rapid and useful for determination of Al3+ in drinking water samples.
关键词： Aluminium,UV-visible spectroscopy,Optical sensor,Gold nanoparticles,X-ray photoelectron spectroscopy,Xylenol orange
更新于2025-09-16 10:30:52
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Capabilities of GaN/AlN/GaN structures as high-intensity pyroelectric laser sensors
摘要： The use of transparent Al2O3 /GaN/AlN/GaN structures as pyrometric sensors for measuring the parameters of high-intensity laser pulses is proposed. The peculiarities of the employment of such sensors in laser fusion facilities are analysed. Post-pulse distributions of the absorbed energy density are obtained for various parameters of both GaN layers. The local maxima of these distributions are minimised by varying the ratio of donor concentration and the ratio of their thicknesses under the condition of invariance of the total absorbed energy. The optimal structure configuration is established in terms of reducing the possible negative effect of laser impact on the pyroelectric coefficient stability.
关键词： pyroelectric effect,aluminium nitride,laser thermonuclear fusion
更新于2025-09-16 10:30:52
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Parametric Analysis of High Power Disk Laser Welding of 5052-H32 Aluminium Alloy
摘要： High power disk laser conducting welding of 2 mm thick AA 5052-H32 was performed within a process window and optimized for improved weld quality (i.e. penetration depth). The macrostructure of the weldment was investigated for the weld penetration depth at varying processing parameters using stereo zoom optical microscopy. The significance of the single effects and interaction effects of the parameters on the weld penetration depth was determined using ANOVA. Maximum weld penetration depth (1.71 mm) was achieved at laser power of 2600 W, welding speed of 0.03 m/s and focal position of -3.75 mm. At 95% confidence, only the welding speed –focal position interaction was found to contribute significantly to the weld penetration depth. The effect of the welding speed was most noticeable at low focal position (F < -3.9), that is, when the workpiece is further away from the focus. A linear regression mathematical model predicting the penetration depth of AA 5052-H32 disk laser weldments to an accuracy of 86% was developed and validated.
关键词： AA 5052-H32 Aluminium Alloy,Optimisation,Regression Model,Disk Laser Welding,ANOVA,Penetration Depth
更新于2025-09-16 10:30:52
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Improving the performance of dye-sensitized solar cells by incoporating a novel ZnO:Al charge injection layer
摘要： In this study, the e?ect of integrating a ZnO:Al (AZO) charge injection layer into dye-sensitized solar cells (DSSCs) is investigated. The AZO charge injection layer was deposited using a low-cost sol-gel deposition method directly onto ?uorine-doped tin oxide (FTO) conducting glass just before TiO2 photoanode coating. The structural and optoelectronic properties of AZO charge injection layer are then investigated as a function of the precursor concentration. The integration of AZO charge injection layer leads to the improvement of power conversion e?ciency (PCE) by preventing the electrolyte coming in contact with FTO and improving charge injection from the charge AZO layer. It was found that there is an optimum AZO precursor concentration for charge injection layer deposition and DSSCs fabricated using higher concentration resulted in reduced photovoltaic performance due to reduced light transparency, whilst charge injection layer deposited at lower precursor concentration were found to reduce DSSC performance due to insu?cient converage.
关键词： Aluminium doped zinc oxide,Dye sensitized solar cells,Injection layer,Sol-gel
更新于2025-09-16 10:30:52
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Effect of Er:YAG laser on debonding strength of laminate veneers
摘要： Objective: The purpose of this study was to evaluate the debonding strength of laminate veneers after using erbium?doped: yttrium aluminium garnet (Er:YAG) laser. Materials and Methods: A total of 60 bovine mandibular incisor teeth were divided into two groups (n = 30). Cylindrical specimens (0.7 mm × 5 mm) were fabricated from Empress II ceramic. Then, they were cemented to incisors using dual?cured resin cement (Variolink II). In the first group, no laser application was performed. The Er:YAG laser was applied on each laminate veneer at the test group for 9 s by using the scanning method. Shear force to remove the laminate veneers were applied with universal testing machine at a crosshead speed of 1 mm/min. Results: Results of this study exhibited significant differences between the control (27.28 ± 2.24 MPa) and test group (3.44 ± 0.69 MPa) (P < 0.05). Conclusion: This study shows that application of Er:YAG laser decreased the bond strength of laminate veneers.
关键词： Debonding,shear bond strength,scanning method,erbium-doped:yttrium aluminium garnet laser,laminate veneers
更新于2025-09-16 10:30:52
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On the occurrence of weld bead porosity during laser vacuum welding of high pressure aluminium die castings
摘要： Due to porosity and incomplete fusion, aluminium high pressure die castings are materials that are known to be difficult to weld. Hereby porosity is mainly caused by hydrogen which is trapped within the weld bead during solidification as a result of insufficient degassing. To enhance degassing and to reduce the influence of surrounding air, laser vacuum welding was applied within the current study. The main goal was to investigate the occurrence of porosity during laser beam welding of aluminium high pressure die castings. To reach this aim, die casting plates were laser welded at varied ambient pressure and investigated by x-ray computed tomography. The analysis of the welds focuses on the size, position, amount and shape of the detected defects depending on the ambient pressure during welding. The results showed a dependency of the occurrence of porosity and the ambient pressure whilst welding.
关键词： Aluminium die castings,Laser vacuum welding,Aluminium,X-ray computed tomography,Laser welding,Porosity
更新于2025-09-12 10:27:22
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Aluminium Matrix Composites Produced by Laser Based Additive Manufacturing
摘要： 3D laser metal deposition (LMD) based on the laser cladding is an established technique for additive manufacturing tasks. Also the laser cladding is a well-known technique to produce aluminum matrix composites reinforced by Si particles. High cooling rates typical for laser treatment enable to eliminate coarse Si particles formation which is a substantial disadvantage of in-situ Al-Si composites produced by traditional manufacturing processes like casting. The coarse Si particles formation reduces Al-Si composites mechanical properties. Extremely non-equilibrium solidification conditions typical for micro LMD process allow to obtain a further structure refinement and its mechanical properties improvement. In this paper the in-situ Al-Si composites produced by micro LMD process with different parameters sets were investigated by fine structure X-ray analysis. The structure and phase composition of in-situ Al-Si composites were described. The influence of cladding parameters on Al-Si composites structure was investigated.
关键词： MMC,aluminium matrix composites,Laser micro cladding,thin-wall parts,fine structure,additive manufacturing,aluminium alloys,X-ray analysis,thin wall
更新于2025-09-12 10:27:22