Humans have never stopped exploring their brains,one of the most complex systems in nature.A thorough understanding of the brain is the ultimate challenge for neuroscientists.As there is a rapid increase in the aging populations and the number of brain disorders,researchers are much more eager to clarify how the billions of
Carbon nanotube yarns(CNTY)possess good specific strength and specific conductivity.As such,their potential for commercial applications is significant.Fatigue performance is a significant consideration in yarn/wire applications.In this study,the flexural fatigue performance of CNTY spun from super-aligned carbon nanotube arrays was investigated using a reversed bending test.The results showed that CNTY exhibited excellent resistance to pure flexural fatigue,significantly outperforming stainless steel wire;CNTY failed where a combination of flexural fatigue and tension–tension fatigue had special hollow fracture morphology,and CNTY resistance remained fundamentally unchanged in the combination fatigue process.
Fu XuXiaolong MoSen WanChangqing JiangHongwei HaoLuming Li
Thin metal sheets are often located in the coupling paths of magnetic coupling energy transfer(MCET) systems. Eddy currents in the metals reduce the energy transfer efficiency and can even present safety risks. This paper describes the use of etched fractal patterns in the metals to suppress the eddy currents and improve the efficiency. Simulation and experimental results show that this approach is very effective. The fractal patterns should satisfy three features, namely, breaking the metal edge, etching in the high-intensity magnetic field region, and etching through the metal in the thickness direction. Different fractal patterns lead to different results. By altering the eddy current distribution, the fractal pattern slots reduce the eddy current losses when the metals show resistance effects and suppress the induced magnetic field in the metals when the metals show inductance effects. Fractal pattern slots in multilayer high conductivity metals(e.g., Cu) reduce the induced magnetic field intensity significantly. Furthermore, transfer power, transfer efficiency, receiving efficiency, and eddy current losses all increase with the increase of the number of etched layers. These results can benefit MCET by efficient energy transfer and safe use in metal shielded equipment.
Qing-feng LIShao-bo CHEWei-ming WANGHong-wei HAOLu-ming LI
The combination of deep brain stimulation(DBS) and transcranial magnetic stimulation(TMS) is expected to provide additional insights into the pathophysiology of some brain diseases. However, when using TMS in patients with DBS implants, the induced voltage between DBS electrodes presents the greatest risk of brain damage. This paper describes the characteristics of the induced DBS electrode voltage due to TMS. We first examined the TMS stimulus signal and the DBS output impedance characteristics, and then experimentally investigated the induced DBS electrode voltage for various DBS and TMS conditions. The results show that many factors impact the induced electrode voltage. The induced electrode voltage with DBS device working in the unipolar mode is greater than that with DBS device working in the bipolar mode. No matter DBS device is turned on or turned off, the induced electrode voltage is almost the same, but it can provide a significant addition to the original stimulus waveform. There are no significant differences in the induced DBS electrode voltage when the DBS system is working at different stimulus intensities. Lowering the TMS stimulus intensity could effectively reduce the induced DBS electrode voltage. The induced electrode voltage is also strongly related to the position of the TMS coil relative to the DBS lead. This study provides further information about the characteristics of the induced DBS electrode voltage in TMS applications and a reference for the combined use of DBS and TMS.
LI QingFengCHEN ShaoBoWANG WeiMingHAO HongWeiLI LuMing
