scholarly journals Пластическая деформация меди в результате воздействия мощного ультрафиолетового наносекундного лазерного импульса

2020 ◽  
Vol 46 (16) ◽  
pp. 51
Author(s):  
Т.В. Малинский ◽  
С.И. Миколуцкий ◽  
В.Е. Рогалин ◽  
Ю.В. Хомич ◽  
В.А. Ямщиков ◽  
...  
Keyword(s):  
Energy Density ◽  
Metal Surface ◽  
Nd:Yag Laser ◽  
Threshold Energy ◽  
Single Pulse ◽  
Polished Surface ◽  
Irradiation Zone

The modification of the polished surface of oxygen-free copper after exposure to a rigidly focused single pulse of a UV Nd:YaG laser was investigated. It was revealed that at pre-threshold energy densities (E ~ 0.6 J / cm2), in the absence of noticeable traces of ablation, an irreversible elevation of the metal surface in the irradiation zone arised. With an increase in the energy density ablation processes noticeably level out this effect.

Laser-Triggered Surface Flashover Characteristics of Al2O3 in Pulsed Voltage

2011 ◽  
Vol 354-355 ◽  
pp. 1224-1227
Author(s):  
Ru Zheng Pan ◽  
You Hua Wang ◽  
Min Tang Li ◽  
Ling Ling Pang ◽  
Jue Wang ◽  
...  
Keyword(s):  
Energy Density ◽  
Nd:Yag Laser ◽  
Delay Time ◽  
Laser Energy ◽  
Test System ◽  
Vacuum Condition ◽  
Surface Flashover ◽  
532 Nm ◽  
Time Decrease ◽  
Pulsed Voltage

Based on the platform of laser-triggered surface flashover in pulsed voltage, experiment of laser-triggered surface flashover is carried out in air and vacuum condition with pulsed voltage. A single/double harmonic, with wavelength of 1064/532 nm, Q-switched Nd:YAG laser is applied to trigger the surface flashover. The test system consists of flat electrodes and columned insulator. The material of electrode is copper and the material of insulator is Al2O3. Laser pulse’s wavelengths are 532nm and 1064nm, and laser is focused with rectangle. The results of experiment show that flashover delay time and jitter time decrease with increase of pulsed voltage or laser energy density, the delay time of 1064nm laser trigger is larger than that of 532nm laser trigger, and the delay time and jitter time in vacuum condition are less than the delay time and jitter time in air condition.

Defects and AlSb Precipitate Nucleation in Laser Irradiated Aluminum

1981 ◽  
Vol 4 ◽  
Author(s):  
P. S. Peercy ◽  
D. M. Follstaedt ◽  
S. T. Picraux ◽  
W. R. Wampler
Keyword(s):  
Room Temperature ◽  
Laser Energy ◽  
Ion Beam ◽  
Threshold Energy ◽  
Single Pulse ◽  
Temperature Profiles ◽  
Beam Analysis ◽  
Slip Deformation ◽  
Precipitate Nucleation ◽  
Substrate Temperatures

ABSTRACTLattice defects and precipitates induced in unimplanted and Sb-implanted <110> single crystal Al by single pulse irradiation with a Q-switched ruby laser were studied using ion beam analysis and electron microscopy. The absorbed laser energy during irradiation is directly measured in these studies to allow precise numerical modeling of the melt times and temperature profiles. For unimplanted Al, slip deformation gives rise to increased channeled yields throughout the analyzed depth and occurs for energies well below the melt threshold energy of 3.5 J/cm2. Slip deformation is also observed for irradiation energies above the melt threshold energy, and melting is accompanied by a discontinuous increase in the minimum channeling yield, X min- Implanted Sb (to ∼2 at.% peak concentrations) is found to impede epitaxial regrowth and result in polycrystalline Al formation for laser energies such that the melt front is believed not to penetrate through the Sb-containing region. For deeper melt depths, a metastable alloy is formed with up to 35% of the Sb located in substitutional sites. AlSb precipitate formation in the melt was not observed for room temperature irradiations; however, randomly oriented AlSb precipitates are observed for irradiation at substrate temperatures of 100 and 200 °C These measurements yield an estimated time for nucleation of AlSb precipitates in molten Al of 5 nsec < tnuc < 25 nsec.

scholarly journals Coating 1-Octanethiol-Coated Copper Nano-Ink on a Paper Substrate via Multi-Pulse Flash Light Sintering for Application in Disposable Devices

2020 ◽  
Vol 1 (1) ◽  
pp. 28-39
Author(s):  
Yeonho Son ◽  
Dongho Shin ◽  
Minkyu Kang ◽  
Caroline Sunyong Lee
Keyword(s):  
Energy Density ◽  
Electronic Devices ◽  
Pure Copper ◽  
Single Pulse ◽  
Radius Of Curvature ◽  
Ambient Conditions ◽  
Paper Substrate ◽  
Pulse Technique ◽  
Dry Coating ◽  
Coating Method

Inkjet-printed patterns were formed on a paper substrate using anti-oxidant copper nano-ink for application to disposable electronic devices. To prevent substrate damage, the pattern was flash light sintered under ambient conditions using the multi-pulse technique. Pure copper nanoparticles were coated with 1-octanethiol for oxidation resistance using the dry-coating method. Mixing these with 1-octanol solvent at a concentration of 30 wt% produced the copper nano-ink. Photo paper was used as the substrate. The contact angle between the photo paper and copper nano-ink was 37.2° and the optimal energy density for the multi-pulse flash light sintering technique was 15.6 J/cm2. Using this energy density, the optimal conditions were an on-time of 2 ms (duty cycle of 80%) for three pulses. The resistivity of the resulting pattern was 2.8 × 10−7 Ω∙m. After bending 500 times to a radius of curvature of 30 mm, the relative resistance (ΔR/R0) of the multi-pulse flash light-sintered pattern hardly changed compared to that of the unbent pattern, while the single-pulse-sintered pattern showed dramatic increase by 8-fold compared to the unbent pattern. Therefore, the multi-pulse light sintering technique is a promising approach to produce an inkjet-printed pattern that can be applied to disposable electronic devices.

Amorphous Gallium Produced By Pulsed Excimer Laser Irradiation

1985 ◽  
Vol 51 ◽  
Author(s):  
J. Fröhlingsdorf ◽  
B. Stritzker
Keyword(s):  
Transition Temperature ◽  
Energy Density ◽  
Excimer Laser ◽  
Low Temperatures ◽  
Threshold Energy ◽  
Residual Resistivity ◽  
Superconducting Transition ◽  
Β Phase ◽  
Excimer Laser Irradiation ◽  
Vapor Quenching

ABSTRACTPure crystalline Ga films (α-Ga, β-Ga) have been irradiated at low temperatures (≤ 20 K) with an Excimer laser. By measuring the superconducting transition temperature Tc and the residual resistivity ≤o, the resulting Ga phases (α-Ga, β-Ga, a-Ga) can be identified.Both crystalline Ga phases can be transformed into the amorphous phase.The threshold energy density for the β→ a transition depends on the film thickness, whereas the α →. a transition occurs always at about 225 mJ/cm2 This behavior is in agreement with earlier observations that a-Ga can grow on top of the in-phase but not on the β-phase.The results of laser quenching are compared with other non-equilibrium techniques for the production of a-Ga, such as vapor quenching and low temperature ion iradiation.

Excimer Laser Crystallization of Nanocrystalline Silicon Thin Films

2015 ◽  
Vol 1120-1121 ◽  
pp. 361-368
Author(s):  
Li Jie Deng ◽  
Wei He ◽  
Zheng Ping Li
Keyword(s):  
Thin Films ◽  
Energy Density ◽  
Excimer Laser ◽  
Silicon Film ◽  
Threshold Energy ◽  
Nanocrystalline Silicon ◽  
Lateral Growth ◽  
Laser Crystallization ◽  
Silicon Thin Films ◽  
Excimer Laser Crystallization

Nanocrystalline silicon (nc-Si) thin film on glass substrate is subjected to excimer laser crystallized by varying the laser energy density in the range of 50~600 mJ/cm2. The effect of excimer laser crystallization on the structure of silicon film is investigated using Raman spectroscopy, X-ray diffraction, atomic force microscopy and scanning electron microscopy. The results show that polycrystalline silicon thin films can be obtained by excimer laser crystallization of nc-Si films. A laser threshold energy density of 200 mJ/cm2 is estimated from the change of crystalline fraction and surface roughness of the treated films. The growth of grain is observed and the crystallization mechanism is discussed based on the super lateral growth model. The nanocrystalline silicon grains in the films act as seeds for lateral growth to large grains.

scholarly journals Adhesion of a self-etching adhesive to caries-affected dentin treated with different methods for caries removal: a preliminary study

2016 ◽  
Vol 19 (4) ◽  
pp. 32
Author(s):  
Adriana Bona Matos ◽  
Cynthia Soares De Azevedo ◽  
Livia Tosi Trevelin ◽  
Ana Cecília Correa Aranha
Keyword(s):  
Energy Density ◽  
Bond Strength ◽  
Nd:Yag Laser ◽  
Er:Yag Laser ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Bonding Performance ◽  
Significant Difference ◽  
Caries Removal ◽  
Etching System

<p><strong>Objective</strong>: The aim of this study was to evaluate the adhesion of a self-etching system to caries-affected dentin (CAD) and sound dentin (SD) after different caries removal techniques by using microtensile bond strength test (μTBS). <strong>Materials</strong> <strong>and</strong> <strong>Methods</strong>: Twenty-four extracted human molars with coronal carious lesions were used. The samples were randomly divided into 5 groups, according to caries removal method: G1 - negative control (no removal); G2 abrasive disc; G3 – slow speed steel bur; G4 - Nd:YAG laser (energy density 21.2J/cm<sup>2</sup>); G5 - Er:YAG laser (energy density 80.24J/cm<sup>2</sup>). SD and  CAD/ infected dentin substrates were tested.  Self-etch system (Clearfil SE Bond) was applied and resin crowns were built up. <strong>Results</strong>: One-way ANOVA showed statistically significant difference between experimental groups (p&lt;0.001), with significantly lower results for infected dentin (G1), when compared to all other experimental groups. A statistically significant higher bond strength value was observed for SD irradiated with Er:YAG laser when compared to CAD. For bur and Nd:YAG laser specimens, SD and CAD showed the same bonding performance. <strong>Conclusion</strong>: infected dentin is not an adequate substrate for bonding; Nd:YAG laser and steel burs showed the same bonding performance for both SD and CAD; while both dentins, when irradiated by Er:YAG laser, did not adequately interact with self-etching system resulting in poor adhesion.</p><p><strong>Keywords</strong>: Er:YAG laser; Nd:YAG laser; Infected dentin; Dentin.</p>

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