摘要：Two-dimensional layered double hydroxides(LDHs)have been identified as promising electrocatalysts for the oxygen evolution reaction(OER);however,the simple and effective synthesis of high-quality LDHs remains extremely challenging and the active sites have not been ***,we report a facile solution-reaction method for preparing an ultrathin(thickness<2 nm)nonprecious CoFe-based ***_(1)Fe_(0.2) LDH delivers a current density of 10 mA cm^(-2) and a high turnover frequency of 0.082 s^(-1) per total 3d metal atoms at a low overpotential of 256 *** mass activity is 277.9 A g^(-1) at an overpotential of 300 mV for the *** studies reveal the Co site as the main active center for the *** doped Fe lowers the reaction barrier by accelerating the charge-transfer *** calculations reveal that the surface Co sites adjacent to Fe atoms are the active centers for the OER and the subsurface Fe dopants excessively weaken the OH^(*)adsorption,thus increasing the energy barrier of the rate-determining *** study can guide the rational design of high-performance CoFe-based LDHs for water splitting.

摘要：目前人们正在积极寻找非贵金属催化剂以取代昂贵的铂系氧还原反应催化剂。本文研究一种非贵金属催化剂TiO_(2)分散在N掺杂碳(TiO_(2)/N—C)上,其在碱性溶液中的ORR活性与20%(wt)Pt/C相当,其中,在0.1 mol/L KOH溶液中,TiO_(2)/N-C表现出0.96 VRHE的起始电位和0.80 VRHE的半波电位;密度泛函理论计算表明,电子从还原的TiO_(2)转移到N-C可以大大增强石墨化N掺杂剂附近的ORR活性;TiO_(2)/N-C在反应条件下也表现出良好的稳定性和对甲醇的耐受性。这为合理设计廉价高活性ORR催化剂提供了一种新方法。

摘要：随着近海渔业的枯竭,海洋养殖业逐渐向深远海发展,但深远海养殖易受极端天气影响,本文基于海洋采油平台设计了一种八边形单元升降式网箱,为降低极端天气对养殖效益的影响提供了可能。针对单元升降式网箱结构安全性问题,本文基于ANSYS/Mechanical建立了单个单元网箱和四单元网箱在水面和水下两种状态的分析模型,通过相位角搜索程序确定不同状态下的工况,最终计算出两组网箱在两种状态下的应力和变形情况,完成对网箱强度的校核。仿真计算结果表明:单元升降式网箱可以通过下降到水面以下的方式有效应对极端天气;支撑桩腿与套筒之间的连接处是单元升降式网箱的结构薄弱处。单元升降式网箱为模块化、高效益化、灵活化深海养殖提供了一种解决方案。

摘要：设计了一款用于高速图像传感器的可自调节、加速补偿CMOS电荷泵锁相环电路,通过在传统锁相环电路拓扑中,附加"双模式"逻辑时控的、低功耗加速充电补偿模块,实现了锁定时间与功耗的双重优化。基于180nm/1.8 V CMOS工艺完成锁相环的电路设计和性能仿真,结果表明,基于所提出的加速补偿方案,改进后的锁相环可有效满足图像传感器对低功耗、高速、高频和低噪声输出特性的需求。在输入频率为1 GHz的参考信号时,压控振荡器可达到0.55~2.82 GHz,即2.27 GHz的频率范围,相位噪声为-98.149 dBc/Hz@1 MHz,锁定时间缩短至5.2μs,整体功耗仅为1.98 mW,同时输出的抖动噪声可低至2.81μV/√Hz@1MHz,多个性能指标优于所对比的同类锁相环电路。