- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Comparative analysis of pulsed Nd:YAG laser welding of 304L and 904L stainless steel
摘要： The current study investigates the comparative study of similar pulsed Nd:YAG laser welding of 304L and 904L stainless steel. In the present study both austenitic stainless steel (304L) and super austenitic stainless steel (904L) are laser welded at 5 mm/s scanning speed, 25 Hz pulse frequency and 0.75 mm laser spot diameter. The ultimate tensile strength of both laser welded specimens were equal to the respective parent metals. The percent of ductility is more in 304L than 904L laser welded specimen comparatively. The weld bead shape of the two welded specimens are V shaped for 304L and H shaped for 904L at the same laser process parameters due to difference in thermophysical properties of the two materials.
关键词： 904L,Pulsed Nd:YAG,Microhardness,304L,Microstructure,Laser welding
更新于2025-09-23 15:21:01
-
Dose-dependent effect of the pulsed Nd:YAG laser in the treatment of crushed sciatic nerve in Wister rats: an experimental model
摘要： The objective of the study was to investigate the efficacy of three energy densities 4, 10, and 50 J/cm2 of pulsed Nd:YAG laser for the treatment of crushed sciatic nerve in Wister rats by evaluating changes in the sciatic functional index and the electrophysiology.A total of 180 Wistar rats were involved in the study. Rats were randomly assigned to five groups. Rats were subjected to the sciatic nerve crushing. Control negative (CONT-ve), which received no crushing; control positive (CONT+ve), which received crushing with no laser; and HILT-4, HILT-10, and HILT-50 groups, which received pulsed Nd:YAG laser (10 Hz, 360 mJ/cm2) with energy densities 4, 10, and 50 J/cm2, respectively. The SFI, the amilitude of compound motor action potential (CMAP) and sciatic motor nerve conduction velocity (MNCV) were measured before and after seven, 14, and 21 days after crushing. For the SFI and electrophysiological analysis, repeated measures ANOVA is used, followed by Bonferroni’s repeated-measures test. Statistical significance was set at p < 0.05. After one week, there was no significant difference in SFI, CMAP, and MNCV among the three laser groups with significant changes between them and CONT-ve and CONT+ve groups. There was a significant increase in either CMAP amplitude or MNCV after 14 days with significant decrease in the SFI after 21 days among all treatment groups. The pulsed Nd:YAG laser applied with energy densities 4, 10, and 50 J/cm2 significantly decreased the SFI and increased the CMAP and MNCV of the crushed sciatic nerve in Wister rats. Among laser doses, the difference in the rate of recovery in the electrophysiology was found after two weeks while in the SFI after three weeks. The improvement after the nerve injury was time and dose dependent.
关键词： Pulsed Nd:YAG laser,Crushing injury,Electrophysiology,Energy density,Sciatic functional index
更新于2025-09-23 15:19:57
-
Laser Welding of Transmitting High-Performance Engineering Thermoplastics
摘要： Laser processing is a rapidly growing key technology driven by several advantages such as cost and performance. Laser welding presents numerous advantages in comparison with other welding technologies, providing high reliability and cost-effective solutions. Significant interest in this technology, combined with the increasing demand for high-strength lightweight structures has led to an increasing interest in joining high-performance engineering thermoplastics by employing laser technologies. Laser transmission welding is the base method usually employed to successfully join two polymers, a transmitting one through which the laser penetrates, and another one responsible for absorbing the laser radiation, resulting in heat and melting of the two components. In this work, the weldability of solely transmitting high-performance engineering thermoplastic is analyzed. ERTALON 6 SA, in its white version, is welded by a pulsed Nd:YAG laser. Tensile tests were performed in order to evaluate the quality of each joint by assessing its strength. A numerical model of the joint is also developed to support the theoretical approaches employed to justify the experimental observations.
关键词： pulsed Nd:YAG laser welding,numerical model,polyamide 6,ERTALON 6 SA,high-performance engineering thermoplastic,mechanical testing
更新于2025-09-19 17:13:59
-
Cytotoxic Effects of Titanium Dioxide Nanaoparticles Synthesized by Laser Technique on Peripheral Blood Lymphocytes and Hep-2 Cell Line
摘要： Objective: This study assay the toxic effects of titani-um dioxide nanoparticles (TiO2NPs) on peripheral blood lymphocytes and Hep-2 cell by measuring Mitotic Index (MI), Blastogenic Index (BI), Total Chromosomal Aberration (TCA) and growth rate of cancer cells. Methods: TiO2NPs were synthesized using laser tech-nique by ablation of titanium target immersed in dis-tilled de-ionized water (DDW) using Q-switched pulsed Nd:YAG laser with repetition rate of 1 Hz, wavelength of 1064 nm, 300 pulses and energy of 400 mJ. Chro-mosomal analyses were carried out at different con-centrations of synthesized TiO2 NPs (0.0, 45, 90, and 180) μg/mL. Results: X-ray diffraction (XRD) exhibited anatase phase of prepared TiO2NPs and showed that the crys-talline structures of TiO2NPs is tetragonal. Absorption spectrum of TiO2 NPs was at ultraviolet-region 215 nm due to Surface Plasmon Resonance (SPR), and the par-ticles size distribution of the prepared TiO2NPs ranged from 40 to 110 nm. Finding showed that both MI and BI suffered from high reduction while TCA suffered from significant elevation represented by Chromatid Breaks (CB), Micronuclei (MN) and Ring Chromosome (RC). The highest proportion of (TCA) has been observed in 180 μg/mL of TiO2NPs, (significant at p≤0.05). while the toxic effects of prepared TiO2NPs on Hep-2 cell line represent decline in growth rate with an increase in concentration of TiO2NPs with malformation in the cell structure and shape and placement of the nucleus. Conclusion: The ablation via Q-switched Nd: YAG laser has adequacy to prepare TiO2NPs with 215 nm absorption spectrum, nearly spherical particles and suitable particle size (40-110 nm). In vitro assay showed that prepared TiO2 NPs have significant cytotoxic effects on peripheral blood lymphocyte and Hep-2 cell line by reduction in both Mitotic index (MI) and blasto-genic index (BI) and growth rate of cancer cells.
关键词： Titanium Dioxide Nanaoparticles,Hep-2 cell line,Mitotic Index,Q-switched pulsed Nd:YAG laser,Chromosomal Aberration,Blastogenic Index
更新于2025-09-12 10:27:22
-
The evaluation of long‐pulsed Nd:YAG laser efficacy and side effects in the treatment of cutaneous vessels on the face and legs
摘要： Background: Long‐pulsed Nd:YAG lasers have been used for the treatment of cutaneous vascular lesions on face and leg veins. Objective: To report our experience with long‐pulsed Nd:YAG lasers for the treatment cutaneous vessels on the face and legs. Materials and Methods: A total of 145 patients with cutaneous vessels on the face and the legs were included in this study. All patients received two treatment sessions, first at the beginning and second after four weeks. Patients were evaluated three times: first at the beginning of the therapy, and second and third after the four weekly follow‐ups. The laser settings of each treatment session were recorded. The physician's assessment of treatment efficiency was taken by comparing gross photograph and clinical evaluation. The grade of improvement, as the percent of reduction in the severity of veins after laser treatment, was determined as follows: <25% improvement (mild); 25%–50% improvement (moderate); 51%–75% improvement (good); and >75% improvement (excellent). The side effects were also recorded. Results: Of the 145 patients who completed the study, 63.6% of patients had vessels on the face, and 36.4% had them on the legs. After the first session, 82.8% of patients have good improvement (51%–75%). After the second session, 78.6% of patients have excellent improvement (>75%). The clinical improvement after the second treatment session was significantly higher than the first treatment session (P ? .05). There were no statistical differences between the treatment areas (P ? .05). The most common side effect was erythema in 12.4% (P ? .05). Conclusion: The Nd:YAG laser is an effective and safe treatment option for the treatment of cutaneous vessels on the face and the legs.
关键词： cutaneous vessels,legs,vascular lesions,long‐pulsed Nd:YAG laser,face
更新于2025-09-12 10:27:22
-
Effect of heat input in pulsed Nd:YAG laser welding of titanium alloy (Ti6Al4V) on microstructure and mechanical properties
摘要： In the present investigation, titanium alloy Ti6Al4V of 1.4 mm thickness has been laser-welded in butt joint configuration using pulsed Nd:YAG laser system. The effects of heat input on weld bead shape, fusion zone width (top, middle, and bottom), heat-affected zone (HAZ) width (top, middle, and bottom), and fusion zone area have been studied. The microstructure and mechanical properties of laser-welded specimens at various heat inputs (43.7–103.5 J/mm) have also been investigated. Microstructures of the fusion zone, HAZ, and parent material have been compared at various heat inputs using optical microscope and field emission scanning electron microscope (FESEM). The mechanical properties such as microhardness and tensile strength of the welded joints at varying heat inputs have been studied. Tensile tests of the welded specimen and base metal have been conducted for analyzing ultimate tensile strength and percentage elongation. Surface topography of the tensile fractured specimen of the welded joints and base metal has been examined to analyze the ductile and brittle behavior. EDS analyses of base metal and fusion zone of the welded specimen have been studied. XRD of the as-received base metal and welded specimen have been measured in the range of 30 to 85° to study the crystallographic structure.
关键词： Ti6Al4V,Microstructure,Laser beam welding,Pulsed Nd:YAG laser,Microhardness,Porosity
更新于2025-09-04 15:30:14