Coprecipitation of copper/zinc compounds in metal salt–urea–water system

A study of composite and structural changes of particles prepared by coprecipitation in solutions of Cu²⁺ and Zn²⁺ salts at different starting molar ratios of the corresponding metal nitrates (4:1, 2:1, 1:1, 1:2, 1:4) in the presence of urea is described. The effects of the initial concentration ratios and the ageing time on the final product were discussed in some detail. The final solids were characterized by SEM–EDS, XRD. On ageing at 85 °C, the change from initially amorphous particles to crystalline structure takes place and the results depend on the metal ratio used.     

基于小波分析频差性的电力电缆故障测距

为了提高电力电缆在线单端故障测距方法运用到放射状中压配电系统的准确性,研究了电压行波在配电系统不同地点的反射和透射频差特性,运用小波变换结果模极大值确定电压行波到来时刻的同时,利用所选小波滤波器相频特性提炼电压行渡信号携带的原有频差特性信息.有效地判断出到达母线的第2个行波是故障点反射波还是对端母线反射波.基于某变电站出线构建EMTP仿真模型,仿真结果表明这种利用小波分析频差性的电力电缆在线单端故障测距方法能够较精确地寻找到故障点.     

Catalytic activity of Ni–YSZ–CeO2 anode for the steam reforming of methane in a direct internal-reforming solid oxide fuel cell

As one of the key technologies in the development of a direct internal-reforming solid oxide fuel cell, catalytic activity and stability of a Ni–YSZ–CeO₂ anode on a zirconia electrolyte for the steam reforming of methane was investigated by experiments using a differential fuel cell reactor. The effects of the partial pressure of CH₄, H₂O and H₂, and temperature as well as the electrochemical oxidation on the catalytic activity were analyzed. It was found that the catalytic activity of the Ni–YSZ–CeO₂ anode was higher than that of the Ni–YSZ reported especially at low temperature. A deterioration of the catalytic activity of the anode was observed at low P_H2 and high P_H2O atmosphere, and also at high current densities. This might be caused by the oxidation of the Ni surface by H₂O in the reaction gas and that produced by the anodic reaction. A rate equation for a fractional function for the steam reforming on open circuit was also proposed.     

Amorphous CoFeP/NC hybrids as highly efficient electrocatalysts for water oxidation

The rational design and regulate structure and composition are pivotal for the development of highly efficient oxygen evolution reaction (OER) catalysts for water splitting. In this study, amorphous CoFeP/NC hybrid electrocatalyst has been synthesized by a simple and effective phosphorization of a CoFe-based coordination polymer under N₂ atmosphere. The synergistic effects between the CoFeP and N-doped carbon has led to high electronic conductivity attributed to the optimal Fe contents with N-doped carbon and enlarged electrocatalytic active surface area aroused by the nanostructure of CoFeP/NC, as well as the surface structural evolution of oxyhydroxide/phosphate during OER process. The resulting Co_0.35Fe_0.17P_0.48/NC electrocatalyst can attain a current density of 10 mA/cm² at an overpotential of 275 mV with a Tafel slope of 31 mV/dec on glassy carbon electrode and 228 mV on Ni foam electrode in 1 M KOH solution, long-term OER stability of this Co_0.35Fe_0.17P_0.48/NC under the applied potential of 1.53 V vs. RHE demonstrates no obvious decline in current densities of 110 mA/cm² within 17 h, which outperforms those of the contrast electrocatalysts in this work and also comparable to that of many of the reported electrocatalysts in the literatures. This Co_0.35Fe_0.17P_0.48/NC electrocatalyst highlights the rational modulation of optimal composition and electronic structure with homogeneous incorporation of the foreign metal-doped and N-doped carbon for the synthesis of highly efficient electrocatalysts toward to the water oxidation reactions.     

CO2地质封存机理——从实验研究角度综述

CO2地质封存是减少碳排放和减缓气候变暖的一种有效措施。本文综述了CO2地质封存研究的内容、方法、手段及其相关理论和研究成果。阐述CO2地质封存的四种碳封存机制背后的物理、地球化学过程,CO2注入试验饱和度分布和渗透率的关系等;简要介绍了岩心驱替试验装置和岩石物理分析和化学分析方法及有关参数的计算。指出现有研究存在岩心–次岩心尺度的微观实验研究和反应性迁移模拟研究不足等问题。     

综掘工作面粉尘在煤巷中的运动规律研究

随着采煤机械化水平的不断提高,井下工作面的粉尘产生量也越来越多,粉尘的污染问题日益突出,造成井下工作面环境的严重污染,直接危及工作人员的身体健康,可燃可爆煤尘的存在给矿井安全生产带来巨大威胁。以煤尘粒径分布函数以及重力、空气浮力和阻力对煤尘的综合作用等研究方法,并以粉尘固体颗粒的物性及粉尘颗粒的受力分析为研究对象,分析固体颗粒在巷道中的运动规律,分析得出粉尘粒径分布规律以及粉尘在煤巷中的运动规律,为超声雾化以及气幕控尘技术提供了重要的理论基础。     

近50多年来北洛河水沙变化特征及原因分析

北洛河流域是黄河粗泥沙的主要来源区之一.基于北洛河流域(氵状)头水文站1950-2006年逐年降水量、径流量和输沙量数据,分析了北洛河径流与输沙变化特征.Mann-Kendall、Spearman检验以及线性趋势拟合均表明,降水量、径流量和输沙量均呈显著减少趋势;利用单位降水产流产沙量距平累积曲线分析表明,北洛河单位降水产流产沙量变化可以分为枯水平沙期、丰水丰沙期、枯水平沙期、丰水枯沙期、丰水丰沙期和枯水枯沙期等6个阶段.分析其变化原因认为,降水是影响径流输沙变化的主要自然因素,其中降水径流关系最为密切;水利水保措施的实施、毁林开荒、修路开矿等破坏活动、国家政策以及法律法规的颁布实施等人类活动同样影响径流、输沙量的变化.     

高通量方法在钎焊领域的应用现状

高通量方法作为“材料基因组技术”三大核心要素之一,在材料成分设计、组织分析、性能优化、过程模拟等方面起着关键性作用. 钎焊技术作为焊接与连接领域的重要分支之一,是现代制造业中材料连接应用最广的方式. 首先对高通量方法在钎焊领域的应用研究进行概述,其次主要对近5年有关高通量制备钎料、软钎焊和硬钎焊领域高通量计算方面的最新研究进行高度归纳、总结,最后提出了目前钎焊基因工程研究的局限性,特别是高通量方法与钎焊技术有机组合方面存在的不足之处,同时指明了高通量方法在钎焊领域应用研究发展的方向,为未来实现钎焊4.0、智能钎焊工厂等提供技术支撑和参考信息.     

煤层巷道周围瓦斯排放宽度研究

根据瓦斯渗流方程、煤层瓦斯流动方程、理想气体状态方程、瓦斯含量方程,建立了煤层瓦斯渗流方程,利用傅里叶变换对方程进行了求解。同时,采用Comosol Multiphysics数值模拟软件对煤层巷道的极限排放宽度进行了数值模拟。结果表明:随着自然排放时间的增加,巷道的极限排放宽度在增加。     

矿业权实地核查数据库的建设与应用

数据库建设是整个矿业权实地核查工作的重要成果体现。本文以山西省为例,介绍了矿业权实地核查工作的属性数据库、空间数据库、数据成果综合、数据汇总与系统建设等主要内容。针对生产实践中存在的问题,设计了矿业权数据建库专用软件,解决了数据库建设的相关课题,为加强矿政管理,获得全面矿业权基本数据,实现新一轮矿业权换证提供依据。