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Effective working parameters of laser micro-/nano-machining
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Modern emerged technologies impose development and fabrication of miniatur-ized parts and devices in the micro- and nano-scale. Producing micro- and nano-featured structures requires nonconventional machining processes where con-ventional machining processes such as grinding, milling and eroding have failed. New emerging processes, such laser machining processes, are still fraught with almost invincible processes. Micro-/nano-machining are the pro-cesses of producing parts, microsystems or features at a scale of a few microm-eters and less than one hundred nanometers, respectively. Precise cutting and clean material removal accompanied with a negligible heat affected zone (HAZ), which are usually the characteristics of laser ablation, have opened a wide door for the evolution of remarkable technologies. This has been demonstrated by applications in different fields such as medicine, biotechnology, materials pro-cessing, microelectromechanical systems, electronics and communications. The continuous development in laser technology in terms of ultra-short pulse width, short wavelength and optics technologies has reduced the drawbacks of diffrac-tion-limited processing accuracies. Laser micro-/nano-machining requires the attainment of high fluence and short interaction time to achieve ablation pro-cesses in nanofabrication and structuring of different materials. To conduct the optimum desired machining process, it is important to integrally consider a number of laser beam and working parameters. Laser wavelength, beam mode, minimum attainable spot size, peak power, pulse duration, pulse repetition rate and scanning speed are some of the important considerations. Manipulating those parameters is crucial for ideal laser ablation represented by yielding the highest resolution of machining with the least lateral dimensions, acceptable depth and minimal or no melt at the edges. The assembly of laser beam delivery and focusing system with an automation system are the essential factors for workpiece positioning and obtaining the desired dimensions. The objective of this chapter is to review the effective parameters associated with laser machin-ing processes that affect the dimensions and quality of laser machining at the micro-/nano-scales in a simple presentation. The review is supported by demonstrating laser processing techniques applied in the field of micro-/nano-machining such as mask, interferometric and scribing techniques.

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Publication Date
Thu Apr 20 2023
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
An Investigation into the Effects of Ubiquinone on Inflammation, Diabetic Myopathy and Endotheliopathy, and CBC Parameters in Diabetic Rats
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Oxidative stress and inflammation are connected to the development of metabolic disorders, such as diabetes. Diabetic-related oxidative stress is caused by the overproduction of oxidative-free radicals, which have been implicated in the mechanism of inflammation and damage to tissues. Our study aimed to investigate the effects of ubiquinone treatment on serum indicators of oxidative stress (malondialdehyde (MDA)), inflammation (interleukin 6 (IL-6)), vascular homeostasis (nitric oxide (NO)), and myopathy (myoglobin (MB))  in addition to measuring blood components parameters in streptozotocin-induced diabetic rats. Rats were separated into three groups; negative control group (N), diabetic control group (D), and ubiquinone-treated diabet

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Publication Date
Sun Feb 03 2019
Journal Name
Iraqi Journal Of Physics
Specific activities and radiation hazard parameters calculations of natural radionuclides in AL-Mustansiriyah university soils using NaI(Tl) detector
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The specific activities of the natural radionuclides U-238 and Th-
232 and K-40 in 14 soil samples collected from different sites from
AL-Mustansiriyah university at two depths (topsoil "surface" and
20cm depth) were be investigated using gamma ray spectrometer
3"x3" NaI(Tl) scintillation detector.
The analysis of the energy spectra of the soil samples show that
these samples have specific activities ranging with (16.08-51.11)
Bq/kg for U-238, (14.79-52.29) Bq/kg for Th-232 and (191.08-
377.64) Bq/kg for K-40, with an average values of 29.37, 34.14 and
289.62 Bq/kg for U-238, Th-232, k-40 respectively. The radiation
hazard parameters of the natural radionuclides; radium equivalent
activity (Raeq), gamma a

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Publication Date
Sat Jan 28 2012
Journal Name
Rafidain Journal Of Science
Photodynamic Effect on Photosensitized Candida albicans with Hematoporphyrin Derivative Using Low Power Diode Laser In Vitro
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Publication Date
Mon Dec 07 2020
Journal Name
Journal Of Advanced Research In Fluid Mechanics And Thermal Sciences
Hybrid Bilayer Heterojunction Al/ZnPc/ZnO /ITO Thin Films Solar Cell Prepared by Pulsed Laser Deposition
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Hybrid bilayer heterojunction Zinc Phthalocyanine (ZnPc) thin-film P-type is considered as a donor active layer as well as the Zinc Oxide (ZnO) thin film n-type is considered as an acceptor with (Electron Transport Layer). In this study, using the technique of Q-switching Nd-YAG Pulsed Laser Deposition (PLD) under vacuum condition 10-3 torr on two ITO (Indium Tin Oxide) and (AL) electrodes and aluminum, is used to construct the hydride bilayer photovoltaic solar cell heterojunction (PVSC). The electrical properties of hybrid heterojunction Al/ZnPc/ZnO/ITO thin film are studied. The results show that the voltage of open circuit (V_oc=0.567V), a short circuit (I_sc=36 ?A), and the fill factor (FF) of 0.443. In addition, the conversion

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Publication Date
Tue Aug 13 2024
Journal Name
Brazilian Dental Science
Poly ether keton keton polymer deposition on laser surface structured commercial pure titanium using magnetron sputtering
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Objective: This study aimed to evaluate the effect of coating titanium (Ti) dental implant with polyether ketone ketone (PEKK) polymer using magnetron sputtering on osseointegration, trying to overcome some of the problems associated with Ti alloys. Material and Methods: Implants were prepared from grade (II) commercially pure titanium (CP Ti), then laser was used to induce roughness on the surface of Ti. PEKK was deposited on the surface of Ti implants by radiofrequency (RF) magnetron sputtering technique. The implants were divided in to three groups: without coating (Ls), with PEKK coating using argon (Ar) as sputtering gas (Ls-PEKK-Ar), and with PEKK coating using nitrogen (N) as sputtering gas (Ls-PEKK-N). All the implants were implante

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Publication Date
Sun Nov 01 2020
Journal Name
Iraqi Journal Of Laser
A Comparison between Er,Cr:YSGG 2780 nm Laser and Carbide Fissure Bur in Root-End resection
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Aim: The Aim of the study is to compare between Er,Cr:YSGG 2780 nm laser and carbide fissure bur in root-end resection regarding the morphological variations, temperature changes and the duration of resection process.

Settings and Design: 5 W, 25 Hz, 50% water, 80% air,25.47 J/cm2 .

Material and method: twenty-one extracted single rooted teeth endodontically were treated, twenty teeth were obturated and divided into two groups according to method of resection. Group 1 root-end resected using cross cut carbide bur while group 2 root-end resected using laser with MGG6 sapphire tip of 600 μm diameter. Temperature on external root surface and duration of resection were recor

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Publication Date
Tue Mar 05 2024
Journal Name
Scientific Reports
Mesoporous Ag@WO3 core–shell, an investigation at different concentrated environment employing laser ablation in liquid
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Abstract<p>In this study, silver-tungsten oxide core–shell nanoparticles (Ag–WO<sub>3</sub> NPs) were synthesized by pulsed laser ablation in liquid employing a (1.06 µm) Q-switched Nd:YAG laser, at different Ag colloidal concentration environment (different core concentration). The produced Ag–WO<sub>3</sub> core–shell NPs were subjected to characterization using UV–visible spectrophotometry, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive spectroscopy, electrical analysis, and photoluminescence PL. The UV–visible spectra exhibited distinct absorption peaks at around 200 and 405 nm, which attributed to the occurrence of surface Plasmon reson</p> ... Show More
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Publication Date
Thu Jun 15 2017
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of nano-hydroxy apatite on re-mineralize white spot lesions prior to orthodontic adhesive removal by different techniques (An In vitro comparative study)
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Background: White-spot lesion is one of the problems associated with the fixed orthodontic treatment. The aims of this in-vitro study were to investigate enamel damage depth on adhesive removal when the adhesive were surrounded by sound, demineralized or demineralized enamel that had been re-mineralized prior to adhesive removal using 10% Nano-Hydroxy apatite and to determine the effect of three different adhesive removal techniques. Materials and methods: Composite resin adhesive (3M Unitek) was bonded to 60 human upper premolars teeth which were randomly divided in to three groups each containing ten sound teeth and ten teeth with demineralized and re-mineralized lesions adjacent to the adhesive. A window of 2 mm was prepared on the bucca

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Publication Date
Sat Jan 20 2024
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Theoretical Study of the Lasing Output for a Quasi-Three-Level Operation in Nd 3+:YAG Thin- Disk Laser
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In this research, the effect of each of the concentrations ( Nd+3) was studied (N) the thickness of the thin disk (d) the number of times that the pumping beam passes through the effective medium of this laser (Mp) the reflectivity of the laser output mirror (R 2) The losses of the effective medium (L) and the pumping power used in achieving the reverse qualification (PP) on each of the pumping threshold capacities (Pp.th) and the output power of the laser (Pout) and the efficiency (ŋ) in Nd3+ thin-disk lasers (TDLs) pumping quasi-three-level With continuous operation (cw), at room temperature, and in the Gaussian mode (TEM00),

We found under these opera

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Publication Date
Mon Apr 01 2019
Journal Name
Biochem. Cell. Arch
Improvement the surface properties of metal valves used in agriculture engine by using CO<inf>2</inf> laser beam
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