A comparative study of electrodes in the direct synthesis of CH4 from CO2 and H2O in molten salts

Since the Industrial Revolution, the heavy reliance on the limited fossil energy has emitted huge number of CO₂ into the air and led to a severely global warming. We propose a new green technology to moderate greenhouse gas CO₂ emission and transform it into low-carbon renewable energy in this paper. Through this manner, electricity is transformed into chemical energy. CO₂ and H₂O is directly simultaneous electrolysis under constant 0.25 A with 30 cm² nickel anode and 30 cm² iron cathode in a 600 °C alkali carbonate with LiOH electrolyte in mole ratio of n_H:n_C = 0.15:1, achieving the storage of electricity to chemical energy. This electrolysis provides a gaseous product comprising 45.9% methane, 53.1% H₂, 0.92% CO and trace amounts of longer (than methane) hydrocarbons. Simultaneously, the current efficiency is still ～51% for 60 min.     

温度层化环境中线羽流的流动特性

为研究层化环境对内部火灾烟气扩散的影响,以线羽流为研究对象,在正常环境下线羽流流动特性研究的基础上,通过理论分析对恒温度梯度环境中线羽流的流动特性进行了分析研究,得到线羽流的扩散半径、轴心速度、轴心密度差随高度的变化规律,线羽流所能达到的最大高度,烟气浮力发生变化的临界高度等.     

页岩气地面工程标准化设计

页岩气藏的特殊物性决定了其地面工程建设必须采用非常规、标准化的技术手段,加之我国页岩气藏地面工程设计面临集输规模不确定性强、管网和站场布局适应性差、工艺设备配套难度大及后期需考虑增压开采等诸多难点,因此要求页岩气地面工程建设必须向"标准化设计、模块化建设、橇装化配备"的方向发展。为此,在文献调研和技术探索的基础上,形成了以"标准化井场布局、通用化工艺流程、模块化功能分区、橇装化设备选型、集约化场地设计、数字化生产管理"为核心的页岩气地面工程标准化设计技术;并以国内川渝地区典型页岩气田为例,讨论其应用背景和地面工艺技术路线,对地面集输系统进行标准化设计,包括标准化工艺流程、模块化集输站场、系列化脱水装置、集约化平面布置,取得了显著的效果。建立了灵活、实用、可靠的地面生产体系,完成了丛式井平台、集气站、配套工程等一系列标准化工艺及模块的设计,形成了一套适应于国内页岩气田地面工程建设的技术体系。     

交流滤波电容器振动噪声特性及声场控制研究

在高电压、大容量的直流输电系统中,交流滤波电容器装置为换流站可听噪声的主要来源之一。本文搭建了一套基于激光测振仪的电容器外壳振动测量试验系统,分别测量了单一频率和多频率合成激励下的电容器外壳振动形态。然后研究了电容器振动噪声特性,得到了不同频率的声辐射效率和各面声贡献量。最后提出了整个电容器装置可听噪声的控制措施。根据电容器声源的相干性及相控阵技术,按照声场聚焦距离和电容器间距要求,提出了改变电容器纵向布置的计算公式。基于试验数据,使用边界元方法(BEM),建立了不同布置方式电容器装置的噪声计算仿真模型,研究表明:电容器底面振动能量远大于侧面,宽侧面振动略大于窄侧面。相控阵布置方式能够在特定区域内降低整个装置的可听噪声水平。     

Geometry and mechanical behaviour of radially retractable roof structures during the movement process

In this paper, the kinematic characteristic of the radially retractable roof structure was firstly discussed and the motion boundary of the system was also studied. The results show that the diameter of the outer boundary of the system increases firstly and then decreases when the roof is open. Moreover, the numerical study of the structural behavior of the retractable roof with radial foldable bars and circumferential foldable bars was carried out, respectively. It can be found the latter one has a better structural behavior. Then the mechanical behaivor of the system during the motion was also investigated. Finally, a loop linkage based on a special scissor-like element was proposed to support the retractable roof.     

Polymerization‐Induced Colloidal Assembly and Photonic Crystal Multilayer for Coding and Decoding

Photonic crystal (PC) films are prepared by precipitation of colloidal crystal seeds in supersaturated solution of particles, followed by crystal growth and structure fixing with photo‐polymerization. As the liquid monomer becomes a solid matrix, the highly concentrated particles are forced to precipitate into colloidal microcrystals in short time, and ‘polymerization‐induced colloidal assembly’ (PICA) is shown to be the major driving force to form colloidal crystals. PICA is intrinsically different from evaporation‐induced colloidal assembly, because the seed formation and crystal growth are separated into two independent steps, which makes the synthesis more flexible, controllable, and efficient. The PICA process is capable of quickly producing PC films with an ultra‐narrow bandgap, tunable thickness, and large size. Based on these characteristics and the blocking effect of the outer PC layer to the reflection signal of inner layer, a coding–decoding system is developed in which the film's composition and stacking sequence can be identified by its distinctive reflection spectrum.     

基于锂电池等效电路模型的阻抗曲线拟合算法

近些年利用电池阻抗谱(EIS)估算锂电池状态的研究取得了较大进展。本文提出了一种EIS等效电路模型参数提取算法,用于分析提取不同状态下的电池等效电路参数,具有简单、不易发散的优点。首先通过结合模型的物理意义计算获得等效电路模型参数初值,然后利用等效电路与EIS之间的映射关系进行迭代,从而实现了参数的提取。对比理论参考值,提取的关键参数的误差低于4.4%。为了获得锂电池在不同荷电状态下的EIS数据,利用电化学工作站在恒温状态下测量选用的磷酸铁锂电池,利用算法编写的软件实现等效电路参数的提取。通过对比不同荷电状态下的等效模型参数,在一定程度上验证了利用EIS快速估计锂电池状态的可行性。     

多振动源激励下船用离心泵振动特性分析

为了确定流体激励和轴系激励对离心泵振动的主要影响,通过对离心泵进行非定常流场计算,分析流体激励和轴系激励诱导离心泵振动特性.选择采用轴系不对中作为激励源,结果表明:轴系不对中时,离心泵在1APF(电机转动频率)处振动响应增强,并出现明显的2APF响应,1BPF(1倍叶片通过频率)处振级和中频段振级几乎无变化;当流体激励并伴有轴系不对中时,离心泵在1APF处和1BPF处出现明显的振动响应,1BPF处的振级与仅轴系激励时相差较大.