Results 11 to 20 of about 9,516 (147)
Engineering 2D Materials for High‐Current‐Density Electrocatalytic Water Splitting
Rare Metals, EarlyView.ABSTRACT Water electrolysis is a key method for sustainable hydrogen production, using water as an abundant resource. However, efficient and stable operation at high current densities remains challenging due to energy losses, catalyst degradation, and limited ion–electron transport.
Tianqi Guan +8 more
wiley +1 more source
Rare Metals, EarlyView.ABSTRACT With the continuous advancement of materials science and technology, the rare metal gallium has increasingly emerged as a promising alternative to the toxic metal mercury. Although existing research has predominantly focused on the high electrical conductivity and excellent deformability of liquid metal (LM), its intrinsic fluidic property ...
Feifan Guo +6 more
wiley +1 more source
A precise two dimensional tracking servo system based on CANopen bus [PDF]
, 2016 在航空航天、民用、军事领域都起到重要作用的双自由度转台是一种复杂的集光机电一体化的设备，整体设备的精度和性能将直接受其性能的影响。因此，如何同时获取良好的动态性能、较小的体积重量、足够的旋转扭矩以及较小的噪声振动是本文亟需解决的问题。 本文根据中波红外光谱分析技术和长波红外成像双波段结合的红外光谱仪设备技术要求，设计了双自由度转台。该转台采用美国COPLEY公司的CANPCI卡作为CAN通讯卡，两台COPLEY驱动器分别作为主机与从机直接驱动作为执行机构的两台交流伺服电机，实现两个自由度上的运动 ...
欧阳琪楠
core
Digital twin-driven control construction for three machines of smart coal mining face [PDF]
In order to further improve the intelligent control level of fully mechanized mining equipment in coal mines and achieve the normalized operation of intelligent mining face, this paper proposes the related concepts and system architecture of intelligent ...
Bing MIAO +3 more
core +1 more source
Gaoya dianqi, 2020 高压直流断路器是多端直流输电及高压直流系统联网的基础和安全保障,它不仅要能够开断短路电流而且要能够开断小负载电流,实现对高压直流系统的保护及控制功能。文中在振荡回路中对机械式高压直流断路器开断大电流及小电流的性能进行了测试。分别测试机械式高压直流断路器开断17.5 kA和开断50 A电流时的恢复电压值和恢复电压变化率。在试验中发现机械式高压直流断路器开断17.5 kA电流时可以在叠加高频振荡电流后的第1次过零点处开断,但是在开断50 A电流时需要在第2次电流过零点处才能开断。开断50 ...
高俊珍 +4 more
doaj
MXene‐Based Electromagnetic Attenuation Materials in Microwave and Terahertz Bands
Rare Metals, EarlyView.ABSTRACT MXenes exhibit considerable potential for developing high‐performance electromagnetic (EM) shielding and absorption materials operating across microwave and terahertz frequencies, due to their tunable surface chemistry and exceptional charge carrier transport properties.
Guozheng Zhang +9 more
wiley +1 more source
Innovation and practice of efficient integrated tunneling and bolting in semi-coal rock roadways [PDF]
The efficient and rapid excavation of semi-coal rock roadways is a major engineering challenge that needs to be addressed urgently in the mines with ten-million-ton productivity in Shaanxi-Inner Mongolia mining area. A series of technical issues, such as
Hong WANG +4 more
core +1 more source
Rare Metals, EarlyView.ABSTRACT Organic‐inorganic metal halide perovskite solar cells (PSCs) are promising for photovoltaics due to their excellent optoelectronic properties. However, achieving high efficiency and stability remains challenging, mainly due to defects and energy losses at the electron transport layer (ETL)/perovskite interface.
Jiahui Jin +8 more
wiley +1 more source
小开机方式下滇西北送广东±800 kV特高压直流被动进入孤岛过电压研究 [PDF]
全球能源互联网, 2018 为使滇西北送广东±800 kV特高压直流输变电工程投运后尽快满送功率，在送端电厂机组长期处于开机量较小的情况下，需云南主网增加外送滇西北直流功率。针对送端小开机方式下直流被动进入孤岛后的系统过电压展开了风险分析，提出了提升直流输送能力的过电压抑制措施并进行了现场调试验证。计算表明：若以传统的过电压保护策略，送端电厂开2机和5机情况下直流输送功率极限分别为1500 MW和3300 MW；采取直流被动进入孤岛后采用先全切交流滤波器组、切断成功后延时闭锁直流的过电压抑制措施后，可以将直流输能力提升至额定功率 ...
施健 +6 more
doaj +1 more source
System development of PCB brush grinding machine based on force-controlled grinding with current feedback [PDF]
, 2011 传统磨削加工中大多采用一次磨削保持进给量不变的加工方式，加工过程中的工件材质、砂轮锋利程度等因素会产生变化，磨削力没有得到控制，会随着这些变化而变化，磨削效率低，导致不能保证加工质量。控制力磨削是一种能够控制切入压力为定值，通过测力反馈和机械运动等实现砂轮对工件的压力的一种磨削方式，其目的是控制磨削过程中的磨削力。在PCB制造过程中，需要一道磨削工序去除PCB表面毛刺和提高PCB金属镀层表面质量，为后续的工艺处理提供保证。由于PCB的原材料的不同，板薄变形大，需要磨削的磨削量较小，磨削过程中较大的磨削力，
王逍
core