- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Ni-NPs doped PVA: An efficient saturable absorber for generation multiwavelength Q-switched fiber laser system near 1.5?μm
摘要： We report on the use of Nickel nanoparticles (Ni-NPs) as saturable absorber (SA) to generate Q-switched fiber laser pulses in C-band. The Ni-NPs were incorporated in polyvinyl alcohol (PVA) to produce thin film-based saturable absorber (SA) and integrated into an erbium-doped fiber laser (EDFL) ring cavity to generate passively Q-switching. The Ni-doped PVA SA reveals modulation depth of 15% and a saturation intensity of 200 MW/cm2. Lasing in CW region begins at 77 mW pump power, whereas stable self-starting Q-switching with a central wavelength of 1563.1 nm begins at 85 mW. By fine adjustment of the laser diode pump power up to 236.4 mW dual-, and triple- lasing lines have been observed at 1563.1, 1563.3 and 1563.4 with side mode suppression ratio (SMSR) of more than 49 dB. The proposed laser is useful for generating pulse laser with a minimum pulse width of 1.5 μs and a maximum repetition rate of 56.79 kHz with a pulse energy of about 4.33 nJ at the maximum pump power of 275 mW. The stability of the pulse is verified from the radio-frequency (RF) spectrum with a measured signal-to-noise ratio (SNR) of 44 dB. The ability of Ni-PVA as an effective SA may lead to further development of pulsed fiber laser in the field of photonics.
关键词： Nickel Nanoparticles,Passive Q-switching,Multiwavelength Laser
更新于2025-09-16 10:30:52
-
Influence of Process Parameters on the Porosity, Accuracy, Roughness, and Support Structures of Hastelloy X Produced by Laser Powder Bed Fusion
摘要： The manufacture of highly complex components from nickel-based superalloys with laser powder bed fusion (L-PBF) technology can reduce the production costs parts with comparable microstructural and mechanical properties when compared to casting. The purpose of this study was to investigate the characteristics of samples produced in commercial Hastelloy X (with w% composition of 21Cr-18Fe-9Mo-0.7W-1.5Co-0.1C-1Si-1Mn-0.5Al-0.15Ti-bal.Ni) with an L-PBF process in terms of build density, accuracy, surface roughness, and interface area between the part and the support structures. Samples were obtained with a high density (99.88%), without cracks and with low surface roughness. From the analysis of the support structures, it emerged that the choice of the parameters between support structures, the lower face of the part (down-skin) and the internal area of the part (in-skin) is fundamental to the correct realization of these structures in order to avoid deformation of the components that is induced by thermal stresses during part building.
关键词： process parameters,nickel super-alloys,additive manufacturing,selective laser melting,Hastelloy X
更新于2025-09-16 10:30:52
-
Performance Enhancement of All-Inorganic Quantum Dot Light-Emitting Diodes via Surface Modification of Nickel Oxide Nanoparticles Hole Transport Layer
摘要： All-inorganic quantum dot light-emitting diodes (QLEDs) show promise for advanced lighting and display due to their superior advantage in stability. However, all-inorganic QLEDs suffer from the low efficiency because of the exciton quenching and inefficient hole transport from inorganic hole transport layer (HTL) to QDs. Herein, we demonstrate an efficient all-inorganic QLED with NiO nanoparticals (NPs) HTL modified by 11-mercaptoundecanoic acid (MUA). The MUA can passivate the defects of NiO and suppress the exciton quenching. Moreover, the declined valance band level of modified NiO could facilitate the hole transport, promoting the charge balance. In addition, the surface engineering improves the quality of NiO film, leading to the decrease of current leakage. As a result, the maximum current efficiency and external quantum efficiency (EQE) of our QLEDs achieve 5.50 cd/A and 1.28%, respectively, exhibiting the enhancement of 4.5 and 1.72 folds, respectively. Meanwhile, the stability of the device is drastically improved by more than 20 folds after modifying the NiO with MUA. The strategy offers a pathway to enhance the efficiency and the operation lifetime of all-inorganic QLEDs.
关键词： exciton quenching,nickel oxide nanoparticles,performance enhancement,surface modification,all-inorganic quantum dot light-emitting diodes
更新于2025-09-16 10:30:52
-
Topographic Measurement of Individual Laser Tracks in Alloy 625 Bare Plates
摘要： Additive manufacturing (AM) combines all of the complexities of materials processing and manufacturing into a single process. The digital revolution made this combination possible, but the commercial viability of these technologies for critical parts may depend on digital process simulations to guide process development, product design, and part qualification. For laser powder bed fusion, one must be able to model the behavior of a melt pool produced by a laser moving at a constant velocity over a smooth bare metal surface before taking on the additional complexities of this process. To provide data on this behavior for model evaluations, samples of a single-phase nickel-based alloy were polished smooth and exposed to a laser beam at three different power and speed settings in the National Institute of Standards and Technology Additive Manufacturing Metrology Testbed and a commercial AM machine. The solidified track remaining in the metal surface after the passing of the laser is a physical record of the position of the air–liquid–solid interface of the melt pool trailing behind the laser. The surface topography of these tracks was measured and quantified using confocal laser scanning microscopy for use as benchmarks in AM model development and validation. These measurements are part of the Additive Manufacturing Benchmark Test Series.
关键词： Additive manufacturing,Welding,Nickel-based superalloys,Topography data,Laser melt pool,Metals
更新于2025-09-16 10:30:52
-
Investigation of Crystallization Process of a Single Crystal Nickel-Based Alloy during the Laser Multilayer Cladding
摘要： The article shows the results of multilayer laser cladding of heat-resistant single crystal nickel-based alloy ZhS32-VI (CSMX-4 analogue). The influence of the main technological parameters on geometry and microstructure formation of deposited beads was investigated. Based on obtained dependencies, the regression equations are compiled for describing the shape of bead and the ratio of directional and equiaxial crystallized sections. The obtained dependencies of regime parameters nomination allow restoring the gas-turbine blades by the method of laser cladding.
关键词： gas-turbine blades,heat-resistant nickel-based alloys,laser cladding,crystallization,single crystal nickel-based alloys
更新于2025-09-12 10:27:22
-
Metal nano-composite assisted photons harvesting in thin film organic photovoltaic
摘要： Nickel oxide (NiO) nano-particles assisted photons harvesting is studied using P3HT:PCBM blend based bulk heterojunction thin film organic solar cell (TFOSC). A comparison between devices that were fabricated at different concentration of NiO and that of the pristine P3HT:PCBM active layer were drawn up. The experimental results suggest that the incorporation of NiO in the solar absorber medium was found to be favourable for solar energy harvesting. At optimum concentration of NiO, in P3HT:PCBM blend active layer, the power conversion efficiency has grown by over 140% compared to the pristine type of devices. Moreover, significant improvement were also recorded on the solar cell fill factor (FF) and short circuit current density (JSC), respectively. The newly fabricated solar cells are discussed in terms of the optical and electrical properties of the solar absorber film.
关键词： Localized states,Solar cell,Nickel Oxide,Nano-composites,Nano-particles
更新于2025-09-12 10:27:22
-
Studying the Effect of Doping with Nickel on Silicon-Based Solar Cells with a Deep p–n-Junction
摘要： It has been shown that the doping of the front side of a solar cell with a deep-level p–n junction with nickel atoms increases short-circuit current density Jsc by 89% and open-circuit voltage Voc by 19.7%. Additional thermal treatment at 700°C for 1 h increases Jsc by 98.4% and Voc by 13.18%. It is presumed that the IR radiation conversion efficiency grows because nickel atoms form clusters, these being getter centers for uncontrolled recombinant impurities.
关键词： photocell,silicon,nickel,lifetime,collection coefficient,thermal annealing,clusters,doping
更新于2025-09-12 10:27:22
-
Laser-induced continuous generation of Ni nanoparticles for organic synthesis
摘要： The possibilities of laser-induced liquid phase chemical deposition (LCLD) of metal for continuous generation of nickel nanoparticles, the sizes of which allow their use as a catalyst for organic reactions are considered. The conditions for obtaining Ni nanoparticles by this method were optimized.
关键词： laser-induced liquid phase chemical deposition,catalyst,nickel,nanoparticle,laser-induced deposition,solution
更新于2025-09-12 10:27:22
-
Comparison of laser metal deposition of Inconel 718 from powder, hot and cold wire
摘要： The present paper details first results on laser metal deposition with a new direct diode laser head which allows for coaxial feed of powder, cold- and hot wire material in a single system. The three process variants are compared for laser metal deposition of Inconel 718. The surface appearance, integrity and microstructure of the specimens built with the LMD head are investigated. The presence and removal of the deleterious Laves phase which is detrimental to the mechanical properties is investigated. The results indicate that the new diode laser head allows for a direction-independent LMD process with low oxygen take-up and high surface quality.
关键词： nickel superalloy,Laves phase,direct diode laser,Laser metal deposition
更新于2025-09-12 10:27:22
-
Analysis of a Ni-Fe-Cr-Mo-Si hardfacing alloy manufactured by laser cladding: influence of the iron content on the wear resistance properties
摘要： In this article, we present an ongoing study on a Ni-Fe-Cr-Mo-Si based alloy, as one of the potential cobalt free hardfacing materials. Here, we analyze the effect of the variation of iron content on microstructure and wear property that is induced by a controlled dilution the 316L substrate, or by direct addition. First, we present the state of the art on the proposed Ni-Cr-Mo-Si based alloy. Then, the laser cladding setup is presented and the process parameter map search of the Ni-Fe-Cr-Mo-Si based alloy too. Then, iron is added to the base Ni-Cr-Mo-Si alloy by direct fusion of the powders coming from two different powder feeders and directly blended into the coaxial nozzle used. Finally the samples are analyzed in iron content, microhardness and microstructure. The tribology tests of the samples exhibit a clear change in wear behavior with the iron content and an improvement at a certain level of iron.
关键词： Tribology,Nickel Base Alloys,Laser Cladding,Hardfacing Materials,Nuclear Energy,Wear resistance
更新于2025-09-12 10:27:22