scholarly journals The Influence of Laser Ablation Parameters on the Holes Structure of Laser Manufactured Graphene Paper Microsieves

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1568
Author(s):  
Barbara Nasiłowska ◽  
Zdzisław Bogdanowicz ◽  
Antoni Sarzyński ◽  
Wojciech Skrzeczanowski ◽  
Małgorzata Djas ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Pulse Energy ◽  
Repetition Rate ◽  
Biological Fluids ◽  
Good Control ◽  
Picosecond Laser ◽  
Solid Particles ◽  
Laser Ablation Method ◽  
Graphene Paper ◽  
The Impact

The graphene paper microsieves can be applied in the filtration of biological fluids or separation of solid particles from exploitation fluids. To produce graphene paper microsieves for specific applications, good control over fabrication should be achieved. In this study, a laser ablation method using a picosecond laser was applied to fabricate graphene paper microsieves. Holes in the microsieves were drilled using pulsed laser radiation with a pulse energy from 5 to 100 µJ, a duration of 60 ps, a wavelength of 355 nm, and a repetition rate of 1 kHz. The impact method was applied using 10 to 100 pulses to drill one hole. To produce holes of a proper diameter which could separate biological particles of a certain size (≥10 µm), optimum parameters of graphene paper laser ablation were defined using the MATLAB software taking into account laser pulse energy, repetition rate, and a desired hole diameter. A series of structural tests were carried out to determine the quality of an edge and a hole shape. Experimental results and Laguerre–Gauss calculations in MATLAB were then compared to perform the analysis of the distribution of diffraction fringes. Optimum experimental parameters were determined for which good susceptibility of the graphene paper to laser processing was observed.

scholarly journals Synthesis of Gadolinium Nanoparticles as a CT-Scan Contrast Agent with Pulse Laser Ablation Method

2021 ◽  
pp. 807-811
Author(s):  
Adilla Luthfia ◽  
Iis Nurhasah ◽  
Ali Khumaeni
Keyword(s):  
Laser Ablation ◽  
Contrast Agent ◽  
Contrast Agents ◽  
Ct Scan ◽  
Repetition Rate ◽  
Blood Circulation ◽  
Ablation Process ◽  
Laser Ablation Method ◽  
Negative Effect ◽  
Molecular Contrast

The use of iodine contrast agents on CT Scan clinically shows a short-term blood circulation, non-specific biodistribution and causes side effects on kidneys. Nanoparticles have a longer half-time vascular than molecular contrast agents so it can be observed for a longer time after injection. Gadolinium (Z = 64) has a higher atomic number and X-ray absorbance coefficient than iodine (Z = 53) and does not have the negative effect on kidneys. The Gd nanoparticles development as a CT Scan contrast agent has potential to give more effectiveness than iodine contrast agents. In this study, Gd nanoparticles were synthesized using pulsed laser ablation method with wavelength 1064 nm, energy 45 mJ, and pulse width 7 ns. The ablation process was carried out for 180 minutes with repetition rate of 10 Hz and 15 Hz. The formation of Gd Nanoparticles was analyzed using UV-Vis spectrophotometer and FTIR (Fourier-Transform Infrared Spectroscopy). Testing the ability of Gd nanoparticles as a contrast agent was done in the diagnosis of head and abdomen using a CT Scan GE CT Optima 580 RT type 229156-3. UV-Vis spectrophotometer analysis showed that Gd nanoparticles had high absorbance at the wavelength less than 250 nm which indicated the formation of Gd2(OH)3 compounds. The repetition rate difference in ablation process resulted in the same concentration of Gd nanoparticles with different contrasts. Repetition rate of 10 Hz produced Gd nanoparticles with HU greater than repetition rate of 15 Hz and closer to HU of iodine. The results indicate that Gd nanoparticles can be used as a CT Scan contrast agent.

Evaluation of Alternative Preparation Methods for Failure Analysis at Modern Chip and Package Technologies

2001 ◽  
Author(s):  
A. Dübotzky ◽  
B. Krüger
Keyword(s):  
Laser Ablation ◽  
Laser Pulse ◽  
Failure Analysis ◽  
Pulse Energy ◽  
Repetition Rate ◽  
Pulse Repetition Rate ◽  
Laser Pulse Energy ◽  
Preparation Methods ◽  
Silicon Thickness ◽  
Gold Wires

Abstract We evaluated laser ablation and sandblasting as preparation methods for package related failures and for backside analysis of ICs. With laser ablation we uncovered gold wedges on an internal board of a PLFBGA package without damage of the gold wires and the board metallization. This was possible by optimization of the laser pulse energy and the pulse repetition rate and by limitation of the ablation area. Sandblasting showed to be a gentle way for backside thinning down to 60 μm silicon thickness. For a surface smoothness sufficient for IR imaging a subsequent planarization treatment is necessary.

Tribological Properties of Multi-Layer a-C:H:W/a-C:H PVD-Coatings Micro-Structured by Picosecond Laser Ablation

2019 ◽  
Vol 809 ◽  
pp. 439-444 ◽  
Author(s):  
Henning Hasselbruch ◽  
Y. Lu ◽  
H. Messaoudi ◽  
Andreas Mehner ◽  
Frank Vollertsen
Keyword(s):  
Laser Ablation ◽  
Laser Scanning ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Picosecond Laser ◽  
Confocal Laser Scanning Microscope ◽  
Hard Coatings ◽  
Confocal Laser ◽  
Constant Degree ◽  
The Impact

An increase of the service life of tribological systems subjected to dynamic-mechanical loads is important for numerous mechanical applications. The present study deals with the impact of several micro-structured surface topographies of graded Cr/CrNx/(Cr,W)Cy/a-C:H:W/a-C:H PVD hard coatings on their friction and wear behavior. The coatings were applied by reactive magnetron sputtering on a hardened 1.2379 steel substrates and subsequently micro-structured by laser ablation using a picosecond laser. Pin-on-disc tests were carried out against aluminum under both oil lubrication and dry conditions. The diameters of the micro-dimples were varied between 50 μm, 100 μm and 150 μm at a constant degree of coating coverage of about 60 %. The coefficients of friction and wear were determined after 20,000 cycles by confocal laser-scanning microscope (CLSM), scanning electron microscopy (SEM) and by energy-dispersive X-ray spectroscopy (EDX) to analyze possible transfer layer formations.

Effect of Laser Pulse Energy on the Characteristics of Cu Nanoparticles Produced by Laser Ablation Method in Acetone

2014 ◽  
Vol 25 (4) ◽  
pp. 1147-1156 ◽  
Author(s):  
Davoud Dorranian ◽  
Seyedeh Arezoo Ahmadi Afshar ◽  
Negar Tahmasebi ◽  
Atefeh Fotovat Eskandari
Keyword(s):  
Laser Ablation ◽  
Laser Pulse ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Cu Nanoparticles ◽  
Laser Ablation Method

scholarly journals Zinc Oxide Nanoparticles (ZnONPs) Photocatalyst using Pulse Laser Ablation Method for Antibacterial in Water Polluted

2020 ◽  
Vol 2 (2) ◽  
pp. 102-106
Author(s):  
Fatkhiyatus Saadah ◽  
Rizka Zakiyatul Miskiyah ◽  
Ali Khumaeni
Keyword(s):  
Zinc Oxide ◽  
Laser Ablation ◽  
Pulse Laser ◽  
Zno Nanoparticles ◽  
Repetition Rate ◽  
Zinc Oxide Nanoparticles ◽  
Pulse Laser Ablation ◽  
Wave Number ◽  
Oxide Nanoparticles ◽  
Laser Ablation Method

Synthesis of zinc oxide nanoparticles by pulse laser ablation method has been successed carried out. Synthesis was carried out in aquades medium with a repetition rate variation of 5 Hz, 10 Hz and 15 Hz pulse laser yielding brown colloids. The higher laser repetition rate, the colloidal color will be more dark brown. Characterization of zinc oxide nanoparticles includes UV-Vis, SEM-EDX, FTIR and XRD. The image of SEM shows that zinc oxide nanoparticles have a round shape. Measurement of particle distribution with imageJ software from SEM images showed that ZnO nanoparticles were 23.63 nm, 12.13 nm and 5.59 nm for 5 Hz, 10 Hz and 15 Hz shots. The EDX spectrum analysis results show that only Zn and O atoms in the ZnO nanoparticles colloid are synthesized. FTIR results showed that sprocket ZnO was formed at wave number 457 cm-1 and 545 cm-1. The XRD analysis results also show some peaks known as the ZnO phase. This indicates that ZnO nanoparticles have been formed. The testing of the antibacterial activity of ZnO nanoparticles using a liquid dilution method with nanoparticle concentrations of 40 ppm, 60 ppm and 80 ppm. The test results showed the percentage of degradation of Escherichia coli bacteria at concentrations of 40 ppm, 60 ppm and 80 ppm respectively at 89.60%, 97.76% and 98, 70%.

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