- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Development of laser ablation absorption spectroscopy for nuclear fuel materials: plume expansion behavior for refractory metals observed by laser-induced fluorescence imaging spectroscopy
摘要： The dynamic behavior of an ablation plume in low pressure rare gas ambient was investigated with laser-induced fluorescence imaging spectroscopy for three refractory metals, i.e. titanium, zirconium and hafnium. A comparison of the plume expansion behaviors for the species of these elements revealed an atomic weight effect on the plume structure formation. A hemispherical thin layer and cavity structure reported previously for gadolinium were observed also for these elements. It was found that the plume size increases as well as the layer thickness decreases with increasing atomic weight. For ground state atoms of Ti, substantial amount of atoms were observed even at the center of the plume. Also, the persistence of the Ti atomic plume was as long as 300 μs, which was significantly longer than the other species studied. Furthermore, the mass-dependent elemental separation was observed in the ablation plume produced from a multielement sample. These results suggest that the observed plume structure arises from the ion-electron recombination process and the recoil of the ablated species during the multiple collisions with gas atoms.
关键词： LIBS,Laser-induced fluorescence spectroscopy,Laser ablation,Ablation plume structure,Refractory metals
更新于2025-09-23 15:21:01
-
Role of laser ablation in multimodal treatment of radioiodine- refractory bone metastases of thyroid cancer: a retrospective study
摘要： Purpose To assess the efficacy, safety, and pain benefits of imaging-guided laser ablation (IGLA) in patients with radioiodine-refractory (RR) bone metastases from differentiated thyroid carcinoma (DTC). Patients and methods The institutional medical records of patients with bone metastases from DTC treated with laser ablation (LA) were reviewed retrospectively. Local response, complications, and effects on pain relief were investigated. Results Six osteolytic lesions in five patients (one male, four females; mean age 65.4 ± 5.1 years, range 58–72) were treated with IGLA. All lesions were osteolytic and all have had previous treatments with high-dose radioiodine therapy followed by external radiotherapy (EBRT). All patients assumed opioid analgesics for severe pain. Overall, the lesions (mean size 5.8 ± 3.2 cm; median 5.0 cm, range 3.0–12.0 cm) underwent nine IGLA sessions (mean 1.8 ± 0.4 sessions; median 2.0 sessions, range 1–2). In four (80%) out five lesions, cross-sectional imaging showed a nearly complete response (CR) while the largest lesion was ablated by 80%. Pain changes were assessed with the Brief Pain Inventory-Short Form, that was administered before IGLA and during a 6-month follow-up. Patients experienced significant reduction in worst pain, average pain, and pain interference. Following IGLA, the average daily opioid requirement rapidly and progressively decreased. Treatments were well-tolerated and no major complications occurred. Conclusions IGLA is an effective and safe debulking procedure and provides significant pain relief in patients suffering from DTC bone metastases that are not responsive to standard treatments. So, IGLA could be considered as part of a multi-modality management of advanced thyroid cancer with RR metastatic skeletal involvement.
关键词： Minimally invasive techniques,Laser ablation,Differentiated thyroid cancer,Thermal ablation therapies,Radioiodine-refractory thyroid cancer,Bone metastases
更新于2025-09-23 15:21:01
-
Investigation the effect of laser ablation parameters in a liquid in order to reduce the pulse energy during laser shock peening
摘要： The features of laser shock peening technology was studied in relation to the physical processes occurring during and after laser treatment. The effect of laser parameters on the results of the process was investigated. It was shown that the reduce of the diameter of the laser spot while maintaining the intensity leads to a decrease in the effect of LSP. This phenomenon was studied from the point of view of the features of plastic deformation at various sizes of the treatment zone using the standard model for the LSP process. Besides the features of the development of a plasma plume during laser ablation in a liquid are considered. It was shown that the liquid determines the geometry of the plume evolution and the shock wave caused by it. The process parameters used and the results obtained are important for the development of low-energy LSP technology.
关键词： Surface treatment,Laser shock peening,Laser-produced plasmas,Laser ablation in liquid,Nickel alloys,Laser pulses,Lasers
更新于2025-09-23 15:21:01
-
[IEEE 2019 14th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT) - Taipei, Taiwan (2019.10.23-2019.10.25)] 2019 14th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT) - Innovative System in Package Design by Laser Ablation Technology
摘要： The 5G revolution brings a lot innovative impact in various applications and business opportunities in mobility, automotive, insdustrial automation and healthcare globally. Therefore, the muti-function integration, form factor miniaturization and time to market of IC package design become the necessary trend in electronic assembly technology. Obviously, system in package (SiP) is the capable solution to meet these requirments and widely applied in the IOT, automotive and sensor module currently. However, the conventional singulation process by blade sawing technology exists the burr residual, inflexible package shape forming and inaccuracy tolerance controlling challenges that brings about low yield and limited package shape design. In this research, the sigulation and metal lid by laser ablation technology in various system in package applications are demonstrated, the metal lid discoloration and burr residual defeat are successfully eliminated by pico second pulses laser technology which shorten the energy absorption time from laser light to electrons and improve the heat-affected zone (HAZ) damage on sawing edge during the ablation process. Therefore, the design of experiment (DOE) shows that the metal lid discoloration rate have been greatly improved from 25% to 0% and without the burr residual issue by utilizing UV laser ablation process. In addition, the package shape forming by UV laser is also studied in this paper, the various geometrical shape that including circle, hexagon and qctagon package appearance are fabricated within 30 um cutting tolerance while without any chipping residual on cutting edge, thus, this formnig technology have been widely applied in various fingerprint sensor and particular module applications in smartphone and automotive industry. The typical reliability testing (Temperature Cycle Test, Hight Temperature Storage Test and unbias HAST) results as a verification. By employing this advanced UV laser ablation technology, the package forming quality and sawing accuracy control can be improved obviously compare to the topically blade sawing process. Undoubtedly, the UV laser ablation with pico pluse technology is absolutely the innovative and powerful weapon to accomplish the high quality SiP design in 5G generation.
关键词： 5G,pico second pulses laser,laser ablation technology,UV laser,package forming,reliability testing,system in package (SiP)
更新于2025-09-23 15:21:01
-
Propulsion effects after laser ablation in water, confined by different geometries
摘要： A Nd:YAG laser with 7-ns pulses and pulse energies up to 10 mJ is used to induce an optical breakdown in the front surface of an aluminum rod, covered by a water layer. The rod is part of a ballistic pendulum. In this way, we study the propulsion effects by means of coupling coefficient and energy-conversion efficiency with respect to different confining geometries, volumes of water applied to the front surface of the rod, and the distance of this surface from the laser-beam focus. Holes with different dimensions are drilled on the target surface and filled with different volumes of water to examine the influence of the confinement by the liquid (a free boundary) and a solid-surface geometry on laser ablation effects. The rod movement and the water ejection after laser ablation are acquired by a high-speed camera with 10k frames per second. The results show that the confinement by cavity substantially increases the propulsion effects by shaping the ejected flow of the liquid; while the cavitation bubble, induced inside the water layer, plays a significant role in propulsion efficiency. From the presented results, it follows that the laser-propelled rod carries below 0.5% of the total mechanical energy after propulsion, while the rest of this energy represents the kinetic energy of the ablated water. As expected, moving the target surface away from the focal position decreases the ablative-propulsion efficiency. When the focus is moved inside the solid target, the decrease occurs due to lower conversion of the pulse energy into the energy of the cavitation bubble. If the focus is moved from the surface outward, the bubble moves towards the liquid–gas interface and it is not able to efficiently eject all the liquid from the target.
关键词： Cavitation bubble,Coupling coefficient,Laser propulsion,Nanosecond laser,Energy-conversion efficiency,Laser ablation
更新于2025-09-23 15:21:01
-
The interaction between the osteosarcoma cell and stainless steel surface, modified by high-fluence, nanosecond laser pulses
摘要： The irradiation of metallic surfaces by high-fluence laser pulses in an oxygen-containing atmosphere inevitably modifies the surface topography, chemistry, and wettability. These modifications significantly influence cell-surface interactions and, consequently, surface biocompatibility. We investigate how surface texturing by high-fluence nanosecond laser pulses from a Nd:YAG laser (wavelength of 1064 nm) influences cell adhesion and morphology with the aim of assessing its impact on initial cell behaviour. Quantitative and qualitative analysis of osteosarcoma cell adhesion, viability, and cell morphology were evaluated after 24-hour exposure to non-treated and laser-textured stainless-steel (AISI 316L) surfaces by fluorescent and scanning electron microscopy. The results reveal that this, initial interaction between the cells and the laser-textured surfaces leads to round shaped cells with a smaller footprint. Contrarily, on the non-processed stainless-steel and control-glass surfaces the polygonal, highly elongated, and flattened cells are observed. The cells on the laser-textured surfaces are less dendritic, with short tubular protrusions and an overexpression of extracellular vesicles, which are rarely found on non-treated and control samples. This likely happens due to the formation of nanostructured, high-temperature oxides that are induced by laser ablation. The analysis by X-ray photoelectron spectroscopy reveals that the laser-textured stainless-steel surfaces contain Cr hexavalent oxide, which is more toxic than the native oxide layer on the non-processed samples.
关键词： MG63 cells,cell adhesion,Laser surface engineering,laser texturing,nanosecond-laser ablation
更新于2025-09-23 15:21:01
-
The art of laser ablation in aeroengine: The crown jewel of modern industry
摘要： In this perspective, laser interaction with materials and its applications in precision engineering are mainly introduced for the manufacturing, as well as maintenance, repair, and overhaul (MRO) of aeroengines. In precision engineering, the laser ablation tool has also been more applicable considering its great advantages in microprocessing and nanofabrication. It is interesting to explore the specific process and characteristics of laser ablation, which play an important role in advanced manufacturing. Due to the complicated production procedures of an aeroengine, it is important to explore the physics behind laser interaction with aerospace and aeronautical metallic materials in order to properly utilize the unique characteristics of lasers, such as high monochromaticity, high brightness, high directivity, and high coherence. Meanwhile, it is beneficial to study the dynamic process of interactions and its mechanisms in laser applications, such as laser cleaning, texturing, and shock peening. There exist both photo-chemical and photo-thermal processes when lasers and materials interact. Several typical cases are introduced, which have great potential and high impact applications in the manufacturing and MRO industry of aeroengines. Based on laser ablation in specific industries, the building-up of MRO support system for aeroengines could be provided by a dynamic mechanism between the pioneering research results and industrial demand, leading to the fast development of advanced high-end manufacturing equipment.
关键词： precision engineering,laser interaction,aeroengine,MRO,laser ablation
更新于2025-09-23 15:21:01
-
Micro/nano processing of natural silk fibers with near-field enhanced ultrafast laser; ?????¨è????o?￠???oè????????????ˉ1?¤????è?????è??è??????o3????·￥;
摘要： Silkworm silk fiber is an attractive material owing to its remarkable mechanical characteristics, excellent optical properties, and good biocompatibility and biodegradability. However, nano-processing of the silk fiber is still a challenge limiting its applications in nanoengineering and related fields. Herein, we report localized near-field enhancement-assisted ablation with an ultrafast laser to break this bottleneck. Localized processing of silk fiber, including nano-holing, nano-grooving, and cutting could retain the key molecular structure building blocks and the pristine functionality of the silk fiber. An extremely narrow nanohole with a width of ~64 nm was successfully achieved. The processed silk fiber can be used to transfer micro/nanoparticles and drugs, showing potential for biomedical engineering. The processing strategy developed in this study can also be extended to other materials, paving a new way for fabricating functional nanostructures with precisely controlled size and morphology.
关键词： nano-processing,ultrafast laser,drug delivery,silk fiber,laser ablation
更新于2025-09-23 15:21:01
-
Laser fabrication of structural bone: surface morphology and biomineralization assessment
摘要： The current work explores the surface morphology of the laser-ablated bone using Yb-fiber coupled Nd:YAG laser (λ = 1064 nm) in continuous wave mode. As the laser-ablated region contains physiochemically modified carbonized and nonstructural region, it becomes unknown material for the body. Thus, biomineralization on such a laser-ablated region was assessed by in vitro immersion test in noncellular simulated body fluid. The presence of hydroxyapatite was detected in the precipitated mineral product using scanning electron microscopy equipped with energy dispersive spectroscopy, and X-ray diffraction analysis. The effect of varying laser parameters on distribution of surface morphology features was identified and its corresponding effect on biomineralization was studied.
关键词： Laser-bone interaction,Surface morphology,Finite element method (FEM) modeling,Laser ablation
更新于2025-09-23 15:21:01
-
Expansion of laser-induced plume after the passage of a counter shock wave through a background gas
摘要： Double-pulsed laser ablation with two targets and lasers in a background gas is a method to form nanoparticle complex. Effects of pulse delay between two lasers on plume expansion dynamics are discussed. The germanium and silicon targets were set parallel to each other and irradiated by two YAG lasers. The germanium target was irradiated followed by irradiation of the silicon target with delay time, td. We found that the expansion distance of delayed silicon plume is enhanced for 2 μs ≤ td ≤ 50 μs, compared to that when only the silicon target is irradiated. For td = 200 μs, the expansion distance of delayed silicon plume is similar to that when only the silicon target is irradiated. We discuss the expansion dynamics of the delayed silicon plume based on the effect of the density distribution induced by the primary germanium plume. Our results indicate that the effect of primary germanium plume remains up to about td = 50 μs, and it disappears by td = 200 μs.
关键词： Shock wave,Pulsed laser ablation,Plume expansion,Pulsed laser deposition
更新于2025-09-23 15:21:01