- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Development of an Intra-Layer Adaptive Toolpath Generation Control Procedure in the Laser Metal Wire Deposition Process
摘要： Recently developed concentric laser metal wire deposition (LMWD) heads allow metal addition processes which are independent of the deposition direction, thus enabling complex paths to be generated. The sensitivity of the process to height deviations has experimentally been observed to be greater with this type of head than with powder ones, therefore requiring more precise and local process control algorithms to be implemented. This work developed a methodology for measuring the part, layer by layer, using a 3D scanner based on structured laser light. Height corrections were applied to the mean and intra-layer height deviations by recalculating the deposition trajectories of the next layer to be deposited. Local height deviations were adjusted by varying the scanning speed, thus increasing the feed rate in the lower areas and decreasing it in the higher ones. Defects generated in the purpose, with height differences within the layer, were successfully corrected. A flat layer was re-established through the application of the control strategy. The internal integrity of the parts due to the scanning speed variation was analyzed, resulting in fully dense parts. The structured light measurement and height correction systems are found to be an affordable and time-efficient solution that can be integrated into an LMWD environment, thereby improving the process robustness.
关键词： cladding,coaxial wire feed,metal wire,additive manufacturing,monitoring,laser deposition,structured light scanning,height control
更新于2025-11-28 14:24:20
-
Influence of Technological Parameters of Direct Laser Deposition Process on the Structure and Properties of Deposited Products from Alloy Ti-6Al-4V
摘要： The technology of direct laser deposition is the most promising for using in various industries. One of the most interesting areas for using this technology is an aviation industry. Due to their unique properties, titanium alloys are widely used in the aircraft industry for gas turbine engine components. In this paper, the effect of DLD process parameters on defect formation and structure is considered. The influence of energy density on the mechanical properties of parts is determined.
关键词： Direct Laser Deposition,additive manufacturing,mechanical properties,Titanium alloys
更新于2025-11-28 14:24:20
-
Crystallographically oriented porous ZnO nanostructures with visible-blind photoresponse: controlling the growth and optical properties
摘要： We have grown catalyst-free crystallographically oriented porous ZnO nanostructures by pulsed laser deposition (PLD) method. The deposition was performed in two stages for each sample. In the first stage, self-seeding of ZnO was performed on the quartz substrate, and the angle of deposition (seeding-angle) was varied. Thus, the growth of seeds is different here. In the second stage, the deposition was performed at a glancing angle (at 85?) for the fixed duration of time to grow the nanostructures. These PLD-grown nanostructures acquire highly oriented wurtzite structure. We find that the seeding-angle during the first stage is the determining deposition parameter which influences the growth and other properties of these nanostructures in a controllable manner. The variation in seeding-angle systematically tunes the crystallographic orientation and porosity, which in turn influences the visible-blindness and ultraviolet (UV) photoresponse of these nanonetworks. Here we report the growth of completely defect-free crystallographically oriented nanostructures with necessary porosity for application in visible-blind UV photodetection.
关键词： Crystalline ZnO,catalyst-free ZnO,glancing angle deposition (GLAD),seeding,pulsed laser deposition (PLD),nanostructures
更新于2025-11-21 11:03:13
-
Controlling porosity and ultraviolet photoresponse of crystallographically oriented ZnO nanostructures grown by pulsed laser deposition
摘要： We have synthesized a series of porous nanostructures of c-axis oriented wurtzite ZnO using glancing angle pulsed laser deposition. During deposition, the oxygen partial pressure (PO2) was varied to study the effects on growth, porosity and optical properties. With varied PO2 the growth of nanostructure changes gradually without losing its crystallographic orientation. The variation in PO2 causes systematic change in porosity of these nanostructures, which strongly influences ultraviolet photoresponse. These results show that the parameters such as surface morphology, growth and porosity as well as the optoelectronic properties can be controlled by variation in PO2 without compromising the crystalline structure.
关键词： Crystalline nanostructures,Photoresponse,Porosity,Ultraviolet,Glancing angle pulsed laser deposition
更新于2025-11-19 16:56:42
-
Near-infrared-light-triggered photoelectrochemical biosensor for detection of alpha-fetoprotein based on upconversion nanophosphors
摘要： A novel photoelectrochemical (PEC) biosensor based on hybrids of NaYF4:Yb, Tm， zinc oxide (ZnO) and cadmium sulfide (CdS) was constructed to detect alpha-fetoprotein (AFP), which possesses the advantages of low background noise and non-damage to the biological substance. Herein, we prepared NaYF4:Yb,Tm/ZnO/CdS composite film electrode by pulsed laser deposition. The selected materials of ZnO and CdS can make full use of the upconversion luminescence (~360nm, ~480nm) of NaYF4:Yb,Tm nanophosphors under 980nm laser excitation. Meanwhile, an effective matching of energy levels between the conduction bands of CdS and ZnO can prompt photoelectrochemical performance of the electrode. The biosensor shows ultrasensitive detection of AFP with a wide linear range from 0.01 ng mL-1 to 200 ng mL-1 and a low detection limit of 5 pg mL-1. Therefore, the proposed PEC biosensor based on upconversion nanophosphors is potentially attractive for achieving excellent photoelectrochemical biosensor for detection of other cancer markers in clinical analysis.
关键词： photoelectrochemical,pulsed laser deposition,upconversion luminescence,near-infrared light-triggered biosensor
更新于2025-11-14 15:27:09
-
Structural, electronic and optical properties of pulsed laser deposited Cu2SnS3 photo absorber thin films: A combined experimental and computational study
摘要： Pulsed laser deposited thin films of Cu2SnS3 (CTS) are characterized for the structural, electronic and optical properties using X-ray diffraction, Raman, UV–Vis-NIR spectroscopy, scanning electron microscopic techniques, and density functional theory. It is observed that thin-film samples annealed at low temperature have a metastable tetragonal structure, whereas the films annealed at 450 °C have a predominant stable monoclinic phase. A direct band gap of 1.1 eV, measured from the transmittance spectra, in close agreement with the theoretical band gap value of 0.89 eV obtained from density functional theory calculations. Optical properties reveal that CTS has a large absorption coefficient ~0.5 × 104 cm?1 at 1.5 eV which is comparable to other CuS based materials like CuInS2 and Cu2ZnSnS4. The direct band gap and large absorption coefficient make CTS as one of the potential alternative absorber materials for thin-film solar cell applications.
关键词： Annealing,Raman spectroscopy,Thin films,Density functional theory,Pulsed laser deposition,Optical properties
更新于2025-10-22 19:40:53
-
Synthesis of Bi <sub/>2</sub> O <sub/>3</sub> films, studying their optical, structural, and surface roughness properties
摘要： Reactive pulse laser deposition system was used to prepare Bi2O3 thin films at different laser fluence. It effect on the physical properties of thin films was investigated. A Polymorphous structure was obtaining from XRD results. While the obtained microscopic results from AFM show that grain size is varied between 33.48nm and 131.6 nm. The estimated band gap value from the optical transmission found to range from 1.7-2.9 eV.
关键词： Pulsed laser deposition,morphological properties,Optical properties,Bismuth trioxide,structural properties
更新于2025-09-23 15:23:52
-
Electroresistance of Pt/BaTiO<sub>3</sub>/LaNiO<sub>3</sub> ferroelectric tunnel junctions and its dependence on BaTiO<sub>3</sub> thickness
摘要： Recently, ferroelectric tunnel junctions (FTJs) have attracted considerable attention due to their great potential in next generation non-volatile memories. In this work, we report on thickness-dependent tunneling electroresistance (TER) and corresponding evolution of transport behavior in Pt/BaTiO3/LaNiO3 FTJs with various BaTiO3 thicknesses of 2.0, 3.2, and 4.8 nm. The TER effect is observed in the 3.2 nm-thick Pt/BaTiO3/LaNiO3 tunnel junction and an ON/OFF current ratio of ~170 is achieved due to the modulation of barrier height by polarization reversal. When the BaTiO3 is increased to 4.8 nm in thickness, the ferroelectric-modulation of the barrier profile becomes more pronounced and the dominant transport mechanism changes from electron tunneling to thermally-activated thermionic injection. As a result, the OFF state current is significantly reduced due to the suppression of the Fowler-Nordheim tunneling with increased width and height of the BaTiO3 barrier. A greatly improved ON/OFF current ratio of ~12500 is thus achieved in the 4.8 nm-thick Pt/BaTiO3/LaNiO3 FTJ device. These results facilitate deeper understanding of the TER effects from the viewpoint of not only the barrier profile but also the transport mechanism.
关键词： Pulsed laser deposition,Ferroelectric tunnel junctions,Ferroelectric memory,Resistive switching
更新于2025-09-23 15:23:52
-
Oxynitride Thin Films versus Particle-Based Photoanodes: a Comparative Study for Photoelectrochemical Solar Water Splitting
摘要： The solar water splitting process assisted by semiconductor photocatalysts attracts growing research interests worldwide for the production of hydrogen as a clean and sustainable energy carrier. Due to their optical and electrical properties several oxynitride materials show great promise for the fabrication of efficient photocatalysts for solar water splitting. This study reports a comparative investigation of particle- and thin films-based photocatalysts using three different oxynitride materials. The absolute comparison of the photoelectrochemical activities favors the particle-based electrodes due to the better absorption properties and larger electrochemical surface area. However, thin films surpass the particle-based photoelectrodes due to their more suitable morphological features that improve the separation and mobility of the photo-generated charge carriers. Our analysis identifies what specific insights into the properties of materials can be achieved with the two complementary approaches.
关键词： Oxynitride,pulsed laser deposition,photoelectrochemistry,thin films,solar water splitting,photoanode
更新于2025-09-23 15:23:52
-
Characterisation of AlN nano thin films prepared by PLD
摘要： Aluminium nitride (AlN) nano thin films have been prepared by pulsed laser deposition (PLD) in this paper. The microstructure and grain size of the nano thin films were characterised by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the PLD conditions such as laser fluence, ambient pressure and substrate temperature influence the thickness, morphology and grain size of the nano thin films obviously, i.e. the surface of the nano thin films becomes rough while the grain size increases with increasing the laser fluence, ambient pressure and substrate temperature. In addition, there exists a preferred orientation growth in the thin films.
关键词： microstructure,pulsed laser deposition (PLD),aluminium nitride,grain size,Nano thin films
更新于2025-09-23 15:22:29