The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Weidong Zhou - One of the best experts on this subject based on the ideXlab platform.
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lubricant evolution and depletion under Laser Heating a molecular dynamics study
Soft Matter, 2012Co-Authors: Yong Li, Chee How Wong, Bei Li, Shengkai Yu, Weidong ZhouAbstract:Understanding the performance of polymeric perfluoro-lubricants under femtosecond Laser irradiation is of great fundamental importance in enhancing the stability and durability of micro- and nano-devices. In this paper, molecular dynamics simulations of perfluoropolyether are carried out to investigate the evolution and depletion of molecularly thin lubricants when subjected to Laser Heating. Ultrathin perfluoropolyether lubricant films are modeled by the coarse-grained bead-spring model and are coated on an inert substrate. Periodical surface morphology and layered film structure are formed in the equilibrium lubricant system due to the polar interaction of functional beads. It is found that the lubricant undergoes severe depletion with an increase in Laser Heating duration, resulting in aggravated lubricant evaporation and raised ridges. A temperature gradient is formed in the radial direction due to the heat transfer between the heated beads and the surrounding lubricants. During the cooling process, the strong functional interaction between end-beads and the substrate layer hinders the recovery and redistribution of depleted lubricant beads, resulting in an undersaturated film. The mechanism of lubricant depletion under Laser Heating is further demonstrated by analyzing the temperature dependence of surface tension. The detailed analyses of lubricant depletion provided in the present work are expected to be guidelines to design novel perfluoropolyether lubricants.
Shaochen Chen - One of the best experts on this subject based on the ideXlab platform.
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Wireless bimorph micro-actuators by pulsed Laser Heating
Sensors and Actuators A-physical, 2005Co-Authors: Shaochen ChenAbstract:Abstract We report an experimental and theoretical investigation on wireless bimorph micro-cantilever (BMC) actuated by pulsed Laser Heating. The micromachined BMC consists of a thin gold layer deposited on a polysilicon layer. A pulsed Nd:YAG Laser of wavelength = 355 nm and pulse width = 12 ns was used to heat the BMC. The movement of the BMC was measured by a displacement sensor. Experimental results revealed the frequency of BMC vibration upon Laser Heating. A two-dimensional (2D) discrete model was developed to simulate the Laser pulse response of the cantilever. The simulation results agreed well with experimental observation, except the minor differences in vibration amplitudes in the model.
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Wireless bimorph micro-actuators by pulsed Laser Heating
Sensors and Actuators A: Physical, 2005Co-Authors: Li-hsin Han, Shaochen ChenAbstract:We report an experimental and theoretical investigation on wireless bimorph micro-cantilever (BMC) actuated by pulsed Laser Heating. The micromachined BMC consists of a thin gold layer deposited on a polysilicon layer. A pulsed Nd:YAG Laser of wavelength = 355 nm and pulse width = 12 ns was used to heat the BMC. The movement of the BMC was measured by a displacement sensor. Experimental results revealed the frequency of BMC vibration upon Laser Heating. A two-dimensional (2D) discrete model was developed to simulate the Laser pulse response of the cantilever. The simulation results agreed well with experimental observation, except the minor differences in vibration amplitudes in the model. © 2004 Elsevier B.V. All rights reserved.
Yong Li - One of the best experts on this subject based on the ideXlab platform.
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lubricant evolution and depletion under Laser Heating a molecular dynamics study
Soft Matter, 2012Co-Authors: Yong Li, Chee How Wong, Bei Li, Shengkai Yu, Weidong ZhouAbstract:Understanding the performance of polymeric perfluoro-lubricants under femtosecond Laser irradiation is of great fundamental importance in enhancing the stability and durability of micro- and nano-devices. In this paper, molecular dynamics simulations of perfluoropolyether are carried out to investigate the evolution and depletion of molecularly thin lubricants when subjected to Laser Heating. Ultrathin perfluoropolyether lubricant films are modeled by the coarse-grained bead-spring model and are coated on an inert substrate. Periodical surface morphology and layered film structure are formed in the equilibrium lubricant system due to the polar interaction of functional beads. It is found that the lubricant undergoes severe depletion with an increase in Laser Heating duration, resulting in aggravated lubricant evaporation and raised ridges. A temperature gradient is formed in the radial direction due to the heat transfer between the heated beads and the surrounding lubricants. During the cooling process, the strong functional interaction between end-beads and the substrate layer hinders the recovery and redistribution of depleted lubricant beads, resulting in an undersaturated film. The mechanism of lubricant depletion under Laser Heating is further demonstrated by analyzing the temperature dependence of surface tension. The detailed analyses of lubricant depletion provided in the present work are expected to be guidelines to design novel perfluoropolyether lubricants.
Bei Li - One of the best experts on this subject based on the ideXlab platform.
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Evolution of Diffusion-Related Degradation of Polymeric Lubricant Under Laser Heating: A Molecular Dynamics Study
Magnetics, IEEE Transactions on, 2014Co-Authors: Bei Li, Chee How Wong, Qiu Bo ChenAbstract:Molecular dynamics simulation coupled with a modified coarse-grained bead-spring model is employed to investigate the diffusion-related degradation of lubricant film under Laser Heating. The lubricant surface morphology and depletion profiles during Laser Heating are studied. It is observed that lubricant film degrades due to thermal diffusion and undergoes severe depletion with increasing Laser Heating duration, resulting in raised ridges around the depleted zone. The diffusion width and depth are evaluated to further explore diffusion-related degradation instability. As expected, the diffusion depth increases rapidly with the Heating duration and the Laser power, while the width would fluctuate around a constant value after initial rapid rise and following slight reduction. In addition, a Gaussian temperature gradient is formed in the radial direction due to the thermal transfer between the heated and surrounding beads. It is also shown that the Laser power plays an important role in the temperature gradient and hence greatly influences the diffusion-related degradation of lubricant film on a solid surface.
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lubricant evolution and depletion under Laser Heating a molecular dynamics study
Soft Matter, 2012Co-Authors: Yong Li, Chee How Wong, Bei Li, Shengkai Yu, Weidong ZhouAbstract:Understanding the performance of polymeric perfluoro-lubricants under femtosecond Laser irradiation is of great fundamental importance in enhancing the stability and durability of micro- and nano-devices. In this paper, molecular dynamics simulations of perfluoropolyether are carried out to investigate the evolution and depletion of molecularly thin lubricants when subjected to Laser Heating. Ultrathin perfluoropolyether lubricant films are modeled by the coarse-grained bead-spring model and are coated on an inert substrate. Periodical surface morphology and layered film structure are formed in the equilibrium lubricant system due to the polar interaction of functional beads. It is found that the lubricant undergoes severe depletion with an increase in Laser Heating duration, resulting in aggravated lubricant evaporation and raised ridges. A temperature gradient is formed in the radial direction due to the heat transfer between the heated beads and the surrounding lubricants. During the cooling process, the strong functional interaction between end-beads and the substrate layer hinders the recovery and redistribution of depleted lubricant beads, resulting in an undersaturated film. The mechanism of lubricant depletion under Laser Heating is further demonstrated by analyzing the temperature dependence of surface tension. The detailed analyses of lubricant depletion provided in the present work are expected to be guidelines to design novel perfluoropolyether lubricants.
Chee How Wong - One of the best experts on this subject based on the ideXlab platform.
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Evolution of Diffusion-Related Degradation of Polymeric Lubricant Under Laser Heating: A Molecular Dynamics Study
Magnetics, IEEE Transactions on, 2014Co-Authors: Bei Li, Chee How Wong, Qiu Bo ChenAbstract:Molecular dynamics simulation coupled with a modified coarse-grained bead-spring model is employed to investigate the diffusion-related degradation of lubricant film under Laser Heating. The lubricant surface morphology and depletion profiles during Laser Heating are studied. It is observed that lubricant film degrades due to thermal diffusion and undergoes severe depletion with increasing Laser Heating duration, resulting in raised ridges around the depleted zone. The diffusion width and depth are evaluated to further explore diffusion-related degradation instability. As expected, the diffusion depth increases rapidly with the Heating duration and the Laser power, while the width would fluctuate around a constant value after initial rapid rise and following slight reduction. In addition, a Gaussian temperature gradient is formed in the radial direction due to the thermal transfer between the heated and surrounding beads. It is also shown that the Laser power plays an important role in the temperature gradient and hence greatly influences the diffusion-related degradation of lubricant film on a solid surface.
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lubricant evolution and depletion under Laser Heating a molecular dynamics study
Soft Matter, 2012Co-Authors: Yong Li, Chee How Wong, Bei Li, Shengkai Yu, Weidong ZhouAbstract:Understanding the performance of polymeric perfluoro-lubricants under femtosecond Laser irradiation is of great fundamental importance in enhancing the stability and durability of micro- and nano-devices. In this paper, molecular dynamics simulations of perfluoropolyether are carried out to investigate the evolution and depletion of molecularly thin lubricants when subjected to Laser Heating. Ultrathin perfluoropolyether lubricant films are modeled by the coarse-grained bead-spring model and are coated on an inert substrate. Periodical surface morphology and layered film structure are formed in the equilibrium lubricant system due to the polar interaction of functional beads. It is found that the lubricant undergoes severe depletion with an increase in Laser Heating duration, resulting in aggravated lubricant evaporation and raised ridges. A temperature gradient is formed in the radial direction due to the heat transfer between the heated beads and the surrounding lubricants. During the cooling process, the strong functional interaction between end-beads and the substrate layer hinders the recovery and redistribution of depleted lubricant beads, resulting in an undersaturated film. The mechanism of lubricant depletion under Laser Heating is further demonstrated by analyzing the temperature dependence of surface tension. The detailed analyses of lubricant depletion provided in the present work are expected to be guidelines to design novel perfluoropolyether lubricants.
