Preparation and Performance of Lithium-Rich Manganese Layered Materials 0.6Li[Li1/3Mn2/3]O2?0.4LiNixMnyCo1-x-yO2(x < 0.6, y > 0)

采用碳酸盐共沉淀法合成出前驱体，然后通过高温固相法制备了富锂锰基材料0.6Li[Li1/3Mn2/3]O2&bull;0.4LiNixMnyCo1-x-yO2（x &lt; 0.6，y &gt; 0）. 使用扫描电镜(SEM)、X射线衍射(XRD)以及电化学方法等手段进行了表征. 高温原位XRD测试结果表明，随着温度和Ni含量增加，材料的晶胞参数发生较大变化，温度达800 oC时，高Ni组成的材料阳离子混排现象严重，并伴有尖晶石相生成. 电性能测试结果表明，在充放电电压为2.0 ~ 4.6 V、电流密度20 mA&bull;g-1条件下，低Ni含量材料表现出较好的电化学性能，首周放电容量达260.1 mA&bull;g-1，首次效率为83.2%，经过50次循环后放电容量保持率高达99.7%，且在电池循环过程中，放电电压平台下降较少.Lithium-rich manganese based cathode materials&nbsp;0.6Li[Li1/3Mn2/3]O2&bull;0.4LiNixMnyCo1-x-yO2 (x &lt; 0.6, y &gt; 0) were synthesized by carbonate co-precipitation and high temperature solid-state reaction. The structures and morphologies of the as-prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). The results of high temperature in-situ XRD test show that the lattice parameters change significantly with increasing temperature and Ni content. The cation mixing gets serious and the spinel phase appears in the high Ni content samples when the temperature is up to 800 oC. Under voltages ranging from 2.0 to 4.6 V, the lower Ni content sample has the highest discharge capacity of 260.1&nbsp;mA&bull;g-1 (the initial coulombic efficiency of 83.2%) at current density of 20 mA&bull;g-1, and the discharge capacity retention is up to 99.7% with the relatively smaller voltage decay after 50 cycles.北京矿冶研究总院课题（No. 02-926）作者联系地址：1.&nbsp;北京矿冶研究总院，北京 100160；2. 北京当升材料科技股份有限公司，北京 100160Author's Address: 1. Beijing General Research Institute of Mining and Metallurgy, Beijing 100160, China; 2. Beijing Easpring Material Technology Co. Ltd., Beijing 100160, China通讯作者E-mail：[email protected]

Simulation research on the serpentine locomotion performance of a snake-like robots

基于用V-REP仿真软件建立的蛇形机器人动力学模型,对蛇形机器人的蜿蜒运动性能进行了研究.首先通过蛇形曲线控制蛇形机器人实现蜿蜒运动,对关节角度和力矩情况进行了分析,其次通过变化蛇形曲线公式中的起始弯角、体内形成波个数、弧长变化率来观察分析这些参数对蛇形机器人蜿蜒运动性能的影响,最后研究分析了蛇形机器人蜿蜒运动的爬坡、转弯性能,得出了对实现蛇形机器人的实用化有理论、技术意义的结论

Simulation research on the serpentine locomotion performance of a snake-like robots

基于用V-REP仿真软件建立的蛇形机器人动力学模型,对蛇形机器人的蜿蜒运动性能进行了研究.首先通过蛇形曲线控制蛇形机器人实现蜿蜒运动,对关节角度和力矩情况进行了分析,其次通过变化蛇形曲线公式中的起始弯角、体内形成波个数、弧长变化率来观察分析这些参数对蛇形机器人蜿蜒运动性能的影响,最后研究分析了蛇形机器人蜿蜒运动的爬坡、转弯性能,得出了对实现蛇形机器人的实用化有理论、技术意义的结论

Acoustic edge mode in spiral-based metamaterials at subwavelength scale

Recently, the quantum effect of condensed matter physics is introduced into the acoustic field, which lays a new pathway to manipulate the acoustic wave. However, the acoustic topological insulator based on Bragg scattering requires their lattice constant to be comparable with the wavelength. In this paper, a 11el subwavelength spiral element on the basis of the Archimedean spiral is proposed. Thanks to the central resonator with a slender curved channels scheme, the subwavelength Dirac cone forms in the band structure. The eigenfrequency of the element can be changed by the spiral geometric parameters, which triggers the topological phase transition characterized by opposite valley Chern numbers. The backscattering-immune unidirectional transmission edge state exists at different topological boundaries, suggesting its great robustness even at the sharp bends. Also the topological edge modes along the Z-shaped interfaces are verified by the experiments and the calculation, which provides an effective structure to control the low frequency acoustic wave transmission