Results 21 to 30 of about 13,167 (170)
, 1979 六十年代中期,美国和加拿大在离心压气机的研究工作中获得了新的突破,他们分别研究成功了单级压比为6～10的离心压气机,从此,高压比离心压气机就成为叶轮机械研究工作中一个很活跃的领域。本文首先介绍高压比离心压气机的发展过程和现状,然后着重对提高离心压气机元件性能和改善设计方法的若干问题进行了讨论 ...
刁正纲, 陈静宜
core
Rare Metals, EarlyView.ABSTRACT A major challenge in fabricating eutectic NiTiNb alloys is the incomplete melting of Nb due to its much higher melting point than the NiTi matrix. In this work, a novel electron‐beam freeform additive manufacturing strategy is developed to eliminate unmelted Nb particles and achieve a fully eutectic structure through independent dual‐wire ...
Qing‐Da Zhang +9 more
wiley +1 more source
Gaoya dianqi, 2022 容性电流开断能力，特别是C2级开断能力，已成为断路器满足工程需求的关键指标，因开断过程中易发生重击穿故障而导致试验失败的风险较大，故需对其容性开断能力进行评估。基于容性电流特点，文中采用“恢复电压”及“最小临界电压”评估其开断容性电流能力，且“恢复该电压”低于“最小临界电压”时，断路器具有开断容性电流的能力。采用电场及气流场耦合分析方法，断路器开断性能进行评估，得到试验工况下“恢复电压”均小于“最小临界电压”，表明该断路器具有容性电流开断能力，顺利通过C2级试验验证，进一步表明采用“最小临界电压 ...
郭自豪 +8 more
doaj
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 The development of high‐performance electromagnetic protection materials integrating broadband absorption and effective shielding capabilities is hindered by challenges in simultaneously optimizing multiple electromagnetic properties through conventional material designs.
Changlong Du +9 more
wiley +1 more source
Gaoya dianqi, 2021 能够快速开断大电流的高压直流断路器是影响直流输电的关键因素之一。提出一种自适应电容调压式高压直流断路器设计方案,通过并联调压电容实现电弧电流的反转,形成多个电流过零点,并在一定时间内将电弧电流限制在零点附近,为灭弧创造良好条件。理论推导和仿真结果表明提出的高压直流断路器方案能够适应不同运行工况,避免电力电子器件的通态损耗,有效减小电弧重燃几率,提高断路器的快速分断能力。
张增强, 解超, 陈伟伟, 辛超山
doaj
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
Dianci bileiqi, 2004 综述了近年来国内外在提高氧化锌电阻片通流能力方面的研究进展。认为影响氧化锌电阻片通流能力的关键因素是电阻片微观结构不均匀性导致电流分布的不均匀性。通过采用湿式化学粉料制备法来提高粉料的均匀性是提高电阻片通流能力的有效途径。而改善粉料的均匀性,从根本上讲是改善添加剂在粉料中的分散均匀性。因此,添加剂在粉料中应尽可能地细化和均匀。
迟屹君 +7 more
doaj
Shuitu Baochi Xuebao, 2021 为探究高寒土坡面细沟侵蚀过程机理，建立科学的坡面细沟输沙能力因子模型，服务高寒坡面水土流失治理工作，以藏东南高寒土壤为研究对象，采用室内径流放水冲刷试验，探讨不同流量和坡度条件下细沟水流输沙能力特征。结果表明：（1）高寒土坡面细沟水流输沙能力的临界坡长随输沙能力的增加而变短，范围为3.27~8.31 m；坡度在15°~25°时，临界坡长大约稳定在5.0 m；（2）不同坡度下，高寒土细沟水流输沙能力与流量表现为明显的线性正相关关系（Tc=Aq）；小坡度的输沙能力受流量的影响程度大于大坡度；（3 ...
喻武 +5 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