scholarly journals Влияние импульсного лазерного ИК-излучения на динамику и морфологию деформационных полос в алюминий-магниевом сплаве

2018 ◽  
Vol 60 (9) ◽  
pp. 1632
Author(s):  
А.А. Шибков ◽  
А.Е. Золотов ◽  
М.Ф. Гасанов ◽  
М.А. Желтов ◽  
К.А. Проскуряков
Keyword(s):  
Laser Pulse ◽  
High Speed ◽  
Laser Pulse Energy ◽  
Video Recording ◽  
Deformation Bands ◽  
Ir Laser ◽  
Order Of Magnitude ◽  
Morphological Transitions ◽  
Plane Specimen ◽  
Through Hole

AbstractThe dynamics and morphology of deformation bands under the simultaneous effect of mechanical loading and pulsed IR laser radiation on the surface of in aluminum–magnesium alloy AlMg6 were studied by high-speed video recording. The conditions, under which a laser pulse pierces a through hole with a diameter of an order of magnitude smaller than the thickness of a plane specimen, thus inducing the development of a complicated spatiotemporal structure of deformation bands and a macroscopic jump in the tension diagram, were determined. The morphological transitions associated with the transformation of the type, shape, and spatiostatistical distribution of bands with a change in the laser pulse energy density were revealed. The probable mechanism of this phenomenon was discussed.

scholarly journals Dependence of laser accelerated protons on laser energy following the interaction of defocused, intense laser pulses with ultra-thin targets

2011 ◽  
Vol 29 (3) ◽  
pp. 345-351 ◽  
Author(s):  
C.M. Brenner ◽  
J.S. Green ◽  
A.P.L. Robinson ◽  
D.C. Carroll ◽  
B. Dromey ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Focal Spot ◽  
Laser Pulse Energy ◽  
Laser Energy ◽  
Spot Size ◽  
Proton Flux ◽  
Focal Spot Size ◽  
Order Of Magnitude ◽  
Laser Focal Spot ◽  
Accelerated Protons

AbstractThe scaling of the flux and maximum energy of laser-driven sheath-accelerated protons has been investigated as a function of laser pulse energy in the range of 15–380 mJ at intensities of 1016–1018 W/cm2. The pulse duration and target thickness were fixed at 40 fs and 25 nm, respectively, while the laser focal spot size and drive energy were varied. Our results indicate that while the maximum proton energy is dependent on the laser energy and laser spot diameter, the proton flux is primarily related to the laser pulse energy under the conditions studied here. Our measurements show that increasing the laser energy by an order of magnitude results in a more than 500-fold increase in the observed proton flux. Whereas, an order of magnitude increase in the laser intensity generated by decreasing the laser focal spot size, at constant laser energy, gives rise to less than a tenfold increase in observed proton flux.

The sensitization of laser-induced heat of Er3+ doped Y2O3 nanocrystals by codoped with Mn2+

2015 ◽  
Vol 29 (22) ◽  
pp. 1550158
Author(s):  
Yunfeng Bai ◽  
Minjie Luan ◽  
Linjun Li ◽  
Zhelong He ◽  
Dongyu Li
Keyword(s):  
Power Density ◽  
Thermal Emission ◽  
Energy Levels ◽  
Excitation Power ◽  
Threshold Power ◽  
Excitation Power Density ◽  
Ir Laser ◽  
Order Of Magnitude ◽  
Low Threshold ◽  
Density Threshold

Low threshold power density cw laser-induced heat has been observed in [Formula: see text] and [Formula: see text] codoped [Formula: see text] nanocrystals under excitation by a 980 nm IR laser. Codoped [Formula: see text] remarkably reduces the power density threshold of laser-induced heat compared with [Formula: see text] doped [Formula: see text] nanocrystals. When the excitation power density exceed [Formula: see text], [Formula: see text] codoped [Formula: see text] nanocrystals emit strong blackbody radiation. The thermal emission of [Formula: see text] should originate from the multiphonon relaxation between neighboring energy levels. One additional UC-PL enhancement is observed. The UC-PL intensity can be enhanced by an order of magnitude through high temperature calcination caused by light into heat.

scholarly journals LiDAR Point Cloud Recognition and Visualization with Deep Learning for Overhead Contact Inspection

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6387 ◽  
Author(s):  
Xiaohan Tu ◽  
Cheng Xu ◽  
Siping Liu ◽  
Shuai Lin ◽  
Lipei Chen ◽  
...  
Keyword(s):  
Deep Learning ◽  
Computational Complexity ◽  
Point Cloud ◽  
High Speed ◽  
Point Cloud Data ◽  
Embedded Devices ◽  
Cloud Data ◽  
Manual Inspection ◽  
Order Of Magnitude ◽  
Supply Systems

As overhead contact (OC) is an essential part of power supply systems in high-speed railways, it is necessary to regularly inspect and repair abnormal OC components. Relative to manual inspection, applying LiDAR (light detection and ranging) to OC inspection can improve efficiency, accuracy, and safety, but it faces challenges to efficiently and effectively segment LiDAR point cloud data and identify catenary components. Recent deep learning-based recognition methods are rarely employed to recognize OC components, because they have high computational complexity, while their accuracy needs to be improved. To track these problems, we first propose a lightweight model, RobotNet, with depthwise and pointwise convolutions and an attention module to recognize the point cloud. Second, we optimize RobotNet to accelerate its recognition speed on embedded devices using an existing compilation tool. Third, we design software to facilitate the visualization of point cloud data. Our software can not only display a large amount of point cloud data, but also visualize the details of OC components. Extensive experiments demonstrate that RobotNet recognizes OC components more accurately and efficiently than others. The inference speed of the optimized RobotNet increases by an order of magnitude. RobotNet has lower computational complexity than other studies. The visualization results also show that our recognition method is effective.

Ultrahigh laser pulse energy and power generation at 10 kHz

2012 ◽  
Vol 37 (15) ◽  
pp. 3231 ◽  
Author(s):  
Frederik Fuest ◽  
Michael J. Papageorge ◽  
Walter R. Lempert ◽  
Jeffrey A. Sutton
Keyword(s):  
Power Generation ◽  
Laser Pulse ◽  
Pulse Energy ◽  
Laser Pulse Energy

Intelligent Attenuator For Laser Pulse Energy And Power Stabilization

1983 ◽  
Author(s):  
Malcolm S. White ◽  
Raymond W. Wyatt ◽  
Anthony G. Brett
Keyword(s):  
Laser Pulse ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Power Stabilization

scholarly journals Understanding of BeCu Interaction Characteristics with a Variation of ns Laser-Pulse Duration

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1423 ◽  
Author(s):  
Dongkyoung Lee
Keyword(s):  
Laser Pulse ◽  
Pulse Duration ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Laser Spot ◽  
Main Body ◽  
Crater Size ◽  
Stamping Process ◽  
Cut Quality ◽  
Mechanical Cutting

An inspection process using a Spring Contact Probe (SCP) is an essential step in the semiconductor-manufacturing process. Many plungers, which are the main body of the SCP, are manufactured by a stamping process. After the stamping process, mechanical cutting is applied and the plunger body may be damaged. Thus, to improve cut quality and productivity while minimizing body damage, laser spot cutting can be used. To fully utilize this technology, it is necessary to investigate interaction characteristics of beryllium copper (BeCu) during laser spot cutting. Effects of a total irradiated laser-pulse energy (1 mJ ~1000 mJ ) and pulse duration (100 ns ~8 ns ) on the material-removal zone, thermal depth, and crater size are examined. The crater size can be affected by the localization of heating dominantly. An incubation model is applied to investigate the correlation between crater size and laser-pulse energy. Surface morphology characteristics such as edge separation, small particles, spatter motion, and soaring-up motion are observed.

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