The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Ke Xia - One of the best experts on this subject based on the ideXlab platform.
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Breakdown of the Sharvin limit in spin pumping with interfacial Rashba spin-orbit coupling
Physical Review B, 2019Co-Authors: Ka Shen, Lei Wang, Ke XiaAbstract:We theoretically investigate the role of the interfacial Rashba spin-orbit coupling in spin pumping based on a nonperturbative calculation. A nonmonotonic behavior is predicted in the Rashba-strength dependence of the Gilbert Damping coefficients. We show that the in-plane Damping Component can exceed the Sharvin limit thanks to the Rashba-field-induced torque. Nevertheless, the pumped spin current remains below the Sharvin limit and satisfies the Onsager reciprocity relations with the spin-current-induced spin-transfer torque.
Ka Shen - One of the best experts on this subject based on the ideXlab platform.
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Breakdown of the Sharvin limit in spin pumping with interfacial Rashba spin-orbit coupling
Physical Review B, 2019Co-Authors: Ka Shen, Lei Wang, Ke XiaAbstract:We theoretically investigate the role of the interfacial Rashba spin-orbit coupling in spin pumping based on a nonperturbative calculation. A nonmonotonic behavior is predicted in the Rashba-strength dependence of the Gilbert Damping coefficients. We show that the in-plane Damping Component can exceed the Sharvin limit thanks to the Rashba-field-induced torque. Nevertheless, the pumped spin current remains below the Sharvin limit and satisfies the Onsager reciprocity relations with the spin-current-induced spin-transfer torque.
Z.r. Zhou - One of the best experts on this subject based on the ideXlab platform.
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Improving Dynamic and Tribological Behaviours by Means of a Mn–Cu Damping Alloy with Grooved Surface Features
Tribology Letters, 2018Co-Authors: D.w. Wang, Huajiang Ouyang, Z.r. ZhouAbstract:In this work, the effect of the Damping Component with/without individual grooved surface features on the friction-induced vibration and noise (FIVN) and surface wear performance is studied experimentally and numerically. The experimental results show that introducing a grooved Damping Component in the system has a significantly improved capability in suppressing the generation of FIVN. In addition, it is observed that the friction system with a grooved Damping Component suffers slighter wear. Numerical results show good agreement with the FIVN events observed in the experimental test. Through analysing the deformation behaviour of Damping Component and the contact behaviour of the friction system during friction process, it is speculated that the deformation behaviour of Damping Component plays a significant role in affecting the contact pressure and FIVN behaviour. In addition, linking the vibration performance and wear evolution, the connection between Damping, and vibration and wear behaviour is discovered, which can further explain why the friction system with a grooved Damping Component shows improved capability in suppressing the FIVN of friction system.
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Grooved-structure design for improved Component Damping ability
Tribology International, 2018Co-Authors: Q. Zhang, D.w. Wang, Junwen Zhao, Z.r. ZhouAbstract:Abstract To investigate the influence of the different structures of elastic Damping Components on vibration performance and tribological characteristics, different-angled grooved structures were designed and manufactured on the Damping Components and Damping ability tests were carried out on the developed experimental setup. Results showed that the system with grooved-structure Damping Components exhibited a lower vibration amplitude and better contact conditions for a pad surface than the system without a Damping Component. To provide a possible explanation of why the improvement effect of different Damping Components on Damping abilities exhibited discrepancy, a hammer impact test was carried out and the contact pressure distribution on a pad surface and the deformations of different grooved Damping Components were simulated using the finite element method.
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The effect of the grooved elastic Damping Component in reducing friction-induced vibration
Tribology International, 2017Co-Authors: D.w. Wang, J. Zhao, Huajiang Ouyang, Z.r. ZhouAbstract:Abstract In this work, the effect of the grooved elastic Damping Component on the friction-induced vibration is investigated by using both experimental and numerical analysis. Experimental results show that the Styrene Butadiene Rubber (SBR) with grooves on its surface can reduce the vibration level, suppress the generation of vibration frequency and alleviate the effect of disc surface run-out. To reveal the role of the grooves in modifying friction-induced vibration, three SBR Components with grooves distributed on three different regions are tested. The results show the grooves in the middle region can reduce the vibration amplitude, while the grooves in both the leading and trailing regions can eliminate higher vibration frequency. Numerical analysis is performed to provide reasonable explanations on experimental phenomenon.
Lei Wang - One of the best experts on this subject based on the ideXlab platform.
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Breakdown of the Sharvin limit in spin pumping with interfacial Rashba spin-orbit coupling
Physical Review B, 2019Co-Authors: Ka Shen, Lei Wang, Ke XiaAbstract:We theoretically investigate the role of the interfacial Rashba spin-orbit coupling in spin pumping based on a nonperturbative calculation. A nonmonotonic behavior is predicted in the Rashba-strength dependence of the Gilbert Damping coefficients. We show that the in-plane Damping Component can exceed the Sharvin limit thanks to the Rashba-field-induced torque. Nevertheless, the pumped spin current remains below the Sharvin limit and satisfies the Onsager reciprocity relations with the spin-current-induced spin-transfer torque.
Yongning Chi - One of the best experts on this subject based on the ideXlab platform.
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small signal instability of pll synchronized type 4 wind turbines connected to high impedance ac grid during lvrt
IEEE Transactions on Energy Conversion, 2016Co-Authors: Bo Wang, Haiyan Tang, Yongning ChiAbstract:Instability phenomenon of type-4 wind turbine during grid faults is increasingly concerned by researchers and may result in failure of low-voltage ride through (LVRT), especially when connected to a high-impedance ac grid. In order to carry out the stability analysis for type-4 wind turbines during deep voltage sag, dynamic model, which reflects the interaction between phase locked loop (PLL) and alternating current control (ACC), is first developed. Eigenvalues and modal analysis show that there is a risk that a pair of poorly damped poles may become unstable, which is mainly dominated by PLL as well as the interaction between PLL and ACC. The mechanism of small-signal instability during LVRT is identified as the insufficiency of Damping. Complex torque coefficient approach is further proposed to study the characteristic of the Damping Component, which is composed of the inherent one determined by PLL and the additional influenced by ACC. Finally, simulated results are presented to verify the analytical results.
