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Preparation, characterization and photocatalytic evaluation of aluminum doped metal ferrites
摘要： Spinel ferrite nano-particles have shown a growing interest in recent years due to their specific magnetic and electrical properties. In this manuscript different types of metal ferrites were prepared and doped with different amounts of Al. Full characterization of the prepared ferrites was performed using X-Ray spectrophotometer (XRD), Electron paramagnetic resonance(EPR), and BET surface area measurements. Photo catalytic activity for degradation of organic dye was examined also for all samples. The results showed that the doping of ferrites with Aluminum make a dramatic change in the photocatalytic behavior. A correlation between the structure and magnetic proprieties with the photocatalytic behavior was evaluated.
关键词： BET,Aluminum dopant,EPR,Ferrites,XRD,Photocatalyst
更新于2025-09-23 15:22:29
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Impacts of Defocusing Amount and Molten Pool Boundaries on Mechanical Properties and Microstructure of Selective Laser Melted AlSi10Mg
摘要： The influences of processing parameters such as volumetric energy density (ε) and, particularly, defocusing amount (DA) on densification, microstructure, tensile property, and hardness of the as-printed dense AlSi10Mg alloy by selective laser melting (SLM) were studied systematically. The molten pool boundaries (MPBs) were found overwhelmingly at regular and complex spatial topological structures affected by DA value to exist in two forms, while the “layer–layer” MPB overlay mutually and the “track–track” MPBs intersect to form acute angles with each other. The microstructure of MPBs exhibits a coarse grain zone near the MPBs and the characteristics of segregation of nonmetallic elements (O, Si) where the crack easily happened. The DA value (?2 to 2 mm) affected both the density and the tensile mechanical properties. High tensile strength (456 ± 14 MPa) and good tensile ductility (9.5 ± 1.4%) were achieved in the as-printed condition corresponding to DA = 0.5 mm. The tensile fracture surface features were analyzed and correlated to the influence of the DA values.
关键词： selective laser melting (SLM),mechanical properties,aluminum alloys
更新于2025-09-23 15:22:29
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Microstructure and mechanical properties of Ti/Al dissimilar joints produced by laser-MIG welding–brazing
摘要： We butt-welded AA6061 aluminum alloy to Ti6Al4V titanium alloy, dissimilar light metals, by using laser-MIG hybrid welding–brazing without grooves. The parameters of the laser and arc were optimized to produce sound joints with good formation and mechanical properties. The microstructure of the layer of intermetallic compounds (IMCs) was investigated by scanning electron microscopy and energy dispersive spectroscopy. We also tested the tensile strength of the joints with and without reinforcement. The morphology and thickness of the IMCs varied throughout the joints. A continuous thin layer of TiAl3 appeared on the top surface of the Ti6Al4V, on which some rod-like IMCs grew toward the fusion zone. In the upper region of the butt plane, because more heat accumulated there from the high-power laser coupled with the MIG arc, double-layer IMCs with a thickness of ～ 10.0 μm formed, composed of TiAl (near the Ti alloy) and TiAl3 (near the fusion zone). In the lower region of the butt plane, the double-layer IMCs became continuous and uniform, the serrated morphology disappeared, and the thickness of the IMC layer decreased to 4.0 μm. On the backside of the joint, the thickness of the compound layer (TiAl3) was about 1.0 μm. The average tensile strengths of the reinforced and unreinforced joints were 226 MPa and 210 MPa, respectively, which are up to 88% and 81% of the AA6061 tensile strength, respectively.
关键词： dissimilar joint,titanium alloy,intermetallic compounds.,Laser-MIG hybrid welding–brazing,aluminum alloy
更新于2025-09-23 15:22:29
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Influence of gold nanolayer coating on the continuous-wave laser ablation of a pure aluminum surface: Evaluations of structural and optical features
摘要： In this paper, formation of uniform and large-area micro/nanostructures on pure aluminum surfaces using a continuous-wave laser irradiation is presented. Gold nanolayer coating was utilized as a confinement layer for controlling the possible hydrodynamic phenomena in a molten area. Dependency of the laser-induced morphology on the thickness of a gold coating was investigated in this regard. Scanning electron microscopy, energy dispersive spectroscopy, grazing test of the X-ray diffraction, and optical absorption/reflection spectroscopy in UV/visible/IR ranges were employed to characterize the samples. Results showed that the formation of uniform structures of average sizes of 50 nm-5μm on aluminum surface was possible following the irradiation of a continuous-wave CO2 laser, delivering 130 W beam power. Alterations of the surface morphology brought about an increase in specific absorption peaks at the UV region and the appearance of an absorption peak in the visible range. In addition, these structure-covered surfaces provided interesting reflection behaviors in different spectral areas, which can clearly reflect their high potential to be used as selective solar absorbers. The results of this investigation indicated that optical characteristics such as absorption and emission coefficients as well as ξ factor were 0.98, 0.13, and 7.53, respectively. It can therefore be concluded that this process can be considered an efficient and fast technique to fabricate selective solar absorbers.
关键词： Nanostructures,Aluminum,Selective solar absorber,Sputtering,Nanolayer,Continuous-wave CO2 laser,Gold,Black carbon
更新于2025-09-23 15:22:29
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Validation of the model of TSL isothermal decay in dosimetric α-Al2O3 crystals
摘要： New features of isothermal build-up of thermally stimulated luminescence (TSL) related to deep traps in anion-deficient alumina single crystals are revealed. It was found that the TSL build-up at 630-750 K depends on the structure of the glow curve and is associated with the presence of a high-temperature component with Tm=700 K. Isothermal TSL build-up for the peak at 573 K is well expressed in UV-irradiated samples and is very weak after sample irradiation by a pulsed electron beam. The TSL build-up for this peak is registered for the luminescence of F centres but is absent for the emission of F2+ centres and chromium ions. The obtained results confirm the validity of the kinetic model of the TSL build-up that takes into account the process of thermal ionization of the excited states of F centres in aluminum oxide.
关键词： TSL build-up,Deep traps,Thermal Ionization of F centres,Aluminum oxide,Thermally stimulated luminescence
更新于2025-09-23 15:22:29
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Equine Surgery || Lasers in Veterinary Surgery
摘要： Surgical lasers facilitate minimally invasive surgery, allow surgical access to otherwise inaccessible areas, and induce tissue interactions, which cannot be obtained with conventional surgical instrumentation. Surgical laser procedures can be performed on an outpatient basis and have eliminated procedures that previously required general anesthesia and hospitalization. Surgeons should be knowledgeable about which procedures can be accomplished with surgical lasers and which are better suited to conventional surgery. This chapter will provide information and guidelines on the use of surgical lasers in equine surgery.
关键词： equine surgery,minimally invasive surgery,carbon dioxide laser,Surgical lasers,neodymium:yttrium-aluminum-garnet laser,holmium:yttrium-aluminum-garnet laser,diode laser
更新于2025-09-23 15:21:01
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Design of color tunable thin film polymer solar cells for photovoltaics printing
摘要： Color tunable thin film polymer solar cells have demonstrated the potentials of a wide applications in photovoltaics printing, which is significant for ink pollution reduction and energy saving. This work presents a new effective approach to realize color-tuning photovoltaic cells with optical microcavity structures. Aluminum-doped zinc oxide is utilized as electron transport layer material. With its high electrical conductivity, the thickness tuning range can be quite large, which means the cavity length has a wide variation range. It thus provides sufficient space for optical thin film design to obtain multi colors. By the transfer matrix method, device reflection and absorption spectra are numerically investigated. Based on that, the optical principles for color tunability are explored. In further step, the relationship between device photovoltaics performance and reflective colors are also discussed. Finally, the color coordinates and luminosities are calculated. As results, the colors of the devices designed are capable to cover a relatively large region in Commission Internationale de l′Eclairage (CIE) 1931 x, y chromaticity diagram, which is available to be integrated into the advertisement poster boards, building wall printing and other display applications.
关键词： optical microcavity,thin film polymer solar cells,aluminum-doped zinc oxide,photovoltaics printing,color tunable
更新于2025-09-23 15:21:01
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Densification behavior, microstructure evolution, and tensile properties of selective laser melting additive manufactured TiB <sub/>2</sub> /AlSi10Mg composite
摘要： The fabrication of TiB2/AlSi10Mg composites by selective laser melting (SLM) additive manufacturing has been conducted. The influence of laser processing parameters on the densification behavior, microstructure evolution, and tensile properties of the SLM-processed composites is addressed. With the increase in laser volume energy density, the densification rate increased and reached 99% at a laser speed of 1000 mm/s. Meanwhile, the TiB2 particles underwent a partial melting behavior with the formation of an irregular pattern in the solidified part and complete melting with the smooth surface of the reinforcing particles as the laser volume energy increased. The cellular-dendritic microstructure and the width of the eutectic phase of the as-fabricated composites were significantly refined due to the high cooling rate and complete melting of the reinforcing particles as the nucleation sites using the laser energy density of 117 J/mm3. Therefore, the micro-hardness, ultimate tensile strength, yielding strength, and elongation of the as-fabricated TiB2/AlSi10Mg composites obtained in this process condition were 131.3 HV0.2, 375 MPa, 260 MPa, and 3.1%, respectively, which were significantly higher than those of the unreinforced AlSi10Mg alloy.
关键词： tensile properties,aluminum-based composite,selective laser melting,microstructure evolution
更新于2025-09-23 15:21:01
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Study on the intelligent model database modeling the laser welding for aerospace aluminum alloy
摘要： With the purpose of improving the modeling e?ciency, the model database is established targeting that in-telligent modeling of laser welding for aerospace aluminum alloy. The model database consists of material database, heat source model database and weld joint structure database. The aerospace aluminum alloys are classi?ed reasonably in order to establish the material model database which can manage the thermo-physical properties of aluminum alloys. The heat source models of laser welding are summarized to establish model database on the basis of the di?erent energy distribution characteristics. The joint structure database includes butt joint, T-joint and lap joint. Modeling of arbitrary structures can be implemented quickly and e?ciently when modelers invoke and assemble this model database. The ?nite element model is e?ciently established and accurately solved by taking the 5A90 and 2219 aluminum alloy laser welding as an example. Finally, it is found that the model database established in this paper can greatly improve the modeling e?ciency of laser welding numerical simulation.
关键词： Laser welding,Model database,Aluminum alloy,Structural model,Heat source model,Material model
更新于2025-09-23 15:21:01
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Performance analysis of slot waveguide using aluminum nitride in slot region
摘要： The major obstacle to accomplish an efficient photonic slot waveguide is its comparatively high propagation loss. In the current work, the silicon-on-insulator based slot waveguide with ultra-low propagation loss has been presented using aluminum nitride (AlN) in the slot region. The performance analysis of the slot waveguide has been done by varying the slot gaps from 20 to 240 nm and by varying the arm width from 160 to 340 nm. As compared with the recently reported works based on different slot waveguides, relatively smaller propagation loss of ~ 0.7 dB/cm has been predicted using the AlN based slot waveguide having a slot gap of 120 nm and arm width of 240 nm. Simulation results have demonstrated that the presence of AlN in the slot gap/low-index region, sandwiched between two high-index (silicon) regions, causes the discontinuity of the electric field of quasi-TE mode between the high-index regions. This results in high confinement of light with the smaller propagation loss in the slot region. Along with this, it has also been observed that the presented slot waveguide has the appreciably good propagation length, with low dispersion characteristics. Hence, this kind of analysis can be extended to realize the various optical devices/applications, such as for coupling, sensing, switching, etc.
关键词： Propagation loss,Aluminum nitride,Slot waveguide,Effective refractive index (ERI),Dispersion
更新于2025-09-23 15:21:01