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During the laser-based directed energy deposition (DED-LB) processing, a WC-12Co composite coating with high hardness and strong wear resistance was successfully prepared on a 316L stainless steel substrate by adopting a high-precision coaxial powder feeding system using a spherical WC-12Co composite powder, which showed a large number of dendritic carbides and herringbone planar crystals on the substrate-binding interface. The influences of laser power on microstructural and mechanical properties (e.g., hardness, friction resistance) of WC-12Co composite surfaces were investigated. The results show that laser power has a significant effect on determining the degree of Co phase melting around the WC particles and the adhesion strength between the matrix and the coating. Lower laser power does not meet the melting requirements of WC particles, thus weakening the molding quality of the composite coating. At high laser power, it is possible to dissolve the WC particles and melt the metal powder between the particles, thus improving the material properties. The laser power increased from 700 W to 1000 W and the average hardness of the coating surface gradually increased from 1166.33 HV to 1395.70 HV, which is about 4-5 times higher than the average hardness of the substrate (about 281.76 HV). In addition, the coatings deposited at 1000 W showed better wear resistance. This work shows that the processing parameters during laser-directed energy deposition can be optimized to prepare WC-12Co composite coatings with excellent mechanical properties.
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http://dx.doi.org/10.3390/ma17174215 | DOI Listing |
J Refract Surg
September 2025
From the Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany and.
Purpose: To evaluate intraocular lens (IOL) power calculation of a non-diffractive extended depth of focus (EDOF) IOL after myopic laser in situ keratomileusis (LASIK) without historical data.
Methods: In this consecutive case series, patients who had undergone lens surgery with implantation of a non-diffractive EDOF IOL after myopic laser in situ keratomileusis (LASIK) at the Department of Ophthalmology, University Hospital Frankfurt, Frankfurt, Germany, were included. Preoperative assessments included biometry and tomography using Scheimpflug technology (Pentacam; Oculus Optikgeräte GmbH).
J Refract Surg
September 2025
From the Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy.
Purpose: To determine the accuracy of a new machine learning-based open-source IOL formula (PEARLS-DGS) in 100 patients who underwent uncomplicated cataract surgery and had a history of laser refractive surgery for myopic defects.
Methods: The setting for this retrospective study was HUMANITAS Research Hospital, Milan, Italy. Data from 100 patients with a history of photorefractive keratectomy or laser in situ keratomileusis were retrospectively analyzed to assess the accuracy of the formula.
Two-photon polymerization (TPP) enables the fabrication of intricate 3D microstructures with submicron precision, offering significant potential in biomedical applications like tissue engineering. In such applications, to print materials and structures with defined mechanics, it is crucial to understand how TPP printing parameters impact the material properties in a physiologically relevant liquid environment. Herein, an experimental approach utilizing microscale tensile testing (μTT) for the systematic measurement of TPP-fabricated microfibers submerged in liquid as a function of printing parameters is introduced.
View Article and Find Full Text PDFAdv Sci (Weinh)
September 2025
Thin Film Materials Research Center, Korea Research Institute of Chemical Technology, Daejeon, 34114, Republic of Korea.
Molybdenum disulfide (MoS) has recently emerged as a promising material for the development of triboelectric nanogenerators (TENGs) owing to its inherently negative triboelectric properties when paired with polymeric layers, along with its notable transparency and mechanical flexibility. However, MoS-based TENGs operating in the contact-separation mode encounter critical limitations, including mechanical wear and limited triboelectric performance, particularly within the constraints of conventional 2D geometries. This paper reports the novel one-step laser-assisted synthesis of hemispherical MoS through the controlled nucleation and growth of MoS precursor seeds.
View Article and Find Full Text PDFSmall Methods
September 2025
Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
Monolithic perovskite/silicon tandem (PST) solar cells are rapidly emerging as next-generation solar cells with significant potential for commercialization. This study presents a proof of concept for a silicon diffused junction-based PST cell, utilizing a passivated emitter rear contact (PERC) cell with a low-temperature (<200 °C) laser-fired contact process to minimize thermal damage. By introducing amorphous silicon to the emitter surface of PERC bottom cell, the open circuit voltage (V) improve from 0.
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