Operando Reconstruction of Porous Carbon Supported Copper Selenide Promotes the C2 Production from CO2RR

Precisely regulating surface reconstruction of copper (Cu) chalcogenides-based catalysts to promote the multicarbon (C₂₊)selectivity of the electrochemical CO₂ reduction reaction (CO₂RR) is hampered by the challenging control of the intractable anions and the optimal Cu^δ+ reduction (0 < δ < 1). Herein, a porous carbon-supported copper selenides electrocatalyst that can remarkably improve the C₂-product yield and especially unveil the time-revolved electrochemical CO₂RR reconstruction process to enable the high C₂-selectivity, most notably for ethanol is constructed. The Faradic efficiency (FE) of C₂-products achieved is as high as ≈85.2% with a partial current density of 229.5 mA cm⁻². Operando infrared spectroscopy and density functional theory (DFT) calculations unravel that the surface Se vacancies (V_Se) formation brings closer the neighboring Cu⁺ atoms and activates the Cu sites, thereby rendering efficient generation of the key intermediates (^*CO and ^*CHO) and lowering the C–C coupling barrier for C₂ production. The appearance of metallic Cu can shorten the next-nearest Cu⁰–Cu⁺ distance for O atom to bridge in, leading to the preferential formation of ^*OC₂H₄ towards ethanol instead of C–O bond cleavage to form ethylene. This work opens the avenue of designing suitable local atomic structures catalysts to engage the intermediates for targeted CO₂RR products.     

基于盒维数与L-Z复杂度的雷达复合干扰特征提取方法

针对射频噪声信号和距离欺骗干扰信号的叠加、秉积和卷积3种形式复合的雷达复合干扰信号,提取了盒维数与L-Z复杂度特征,并对盒维数特征的抗噪性能进行了理论推导.通过仿真实验,求得了不同干噪比(Jam-ming-to-noise ratio,JNR)下的L-Z复杂度与盒维数特征分布.最后采用二维特征联合识别方法,对3种雷达复合干扰信号进行了识别,JNR为0 dB时识别概率达到85%以上.     

Error suppression techniques for energy-efficient high-resolution SAR ADCs

The successive approximation register (SAR) is one of the most energy-efficient analog-to-digital converter (ADC) architecture for medium-resolution applications. However, its high energy efficiency quickly diminishes when the target resolution increases. This is because a SAR ADC suffers from several major error source, including the sampling kT/C noise, the comparator noise, and the DAC mismatch. These errors are increasing hard to address in high-resolution SAR ADCs. This paper reviews recent advances on error suppression techniques for SAR ADCs, including the sampling kT/C noise reduction, the noise-shaping (NS) SAR, and the mismatch error shaping (MES). These techniques aim to boost the resolution of SAR ADCs while maintaining their superior energy efficiency.     

基于运动蓄电的智能温控衣设计

针对目前市场上的温控衣只能通过市电充电,导致在寒冷的边疆等充电不便的条件下不能长时间使用的现状,设计了一种能运动蓄电、手机调温的智能温控衣。运动蓄电采用人体运动切割磁感线,产生电能给蓄电池充电;手机调温采用蓝牙通信技术,实现温控衣与智能手机的通信;STM32芯片作为控制核心,利用增量式PID算法使温控衣的温度始终保持在用户所设定的温度。测试结果表明,当运动速度达到2m/s(>2m/s)时,机械能转换电能的效率达到(超过)电源适配器充电的效果,解决了温控衣仅依赖市电充电的问题。     

基于InTouch组态软件的变电站自动化监控系统

介绍了Invensys旗下Wonderware公司的HMI产品InTouch在变电站监控系统中的应用.     

燃气安装成本控制管理

目前燃气管网的安装是燃气公司的重要收入,但安装成本也是公司的重要支出,如何控制安装成本提高资金利用率和投资回收率是每个燃气公司面临的重要课题.本文将从设计、施工、材料、质量等方面探讨安装成本的控制管理.     

确保FF现场总线仪表系统开车一次成功的重要措施

信息化、数字化、网络化,已与人们的日常生活息息相关,倍受青睐。在化工厂实现网络化管理、信息化管理是工业企业发展的趋势,基于基金会现场总线技术的自控仪表在石油化工装置以其独特的技术上的特点和其它诸多的优越性,在化工自动化控制领域占据了很重要的位置。为此,在新技术、新材料、新工艺的使用上,更要认真对待,在施工的各个环节中如何确保现场总线仪表系统的正常运行尤为关键。