交变应力频率对E690钢在3.5%NaCl溶液中腐蚀电化学行为的影响

采用电化学技术与微观形貌观察,研究了不同频率(0.1,0.5,1.0,1.3,1.8和2.0 Hz)弹性交变应力下E690高强海洋工程用钢在3.5%(质量分数) NaCl溶液中的腐蚀电化学行为,探讨了加载频率对腐蚀反应机理的影响。结果表明,存在一个临界频率,将交变应力作用下腐蚀电化学行为分为两个不同的阶段。加载频率在临界频率以下时,随着弹性交变应力加载频率的增大,E690钢的应变速率峰值增大,钢的表面产生活性位点增多,腐蚀过程主要受活化控制,腐蚀速率和局部腐蚀面积均随着加载频率的提高而增大。加载频率超过临界频率时,腐蚀过程主要受扩散控制,腐蚀速率和局部腐蚀面积不受加载频率变化的影响。     

电涌保护器质量监管与抽样检测的探讨

阐述了SPD质量监管的必要性,并对监管的主要手段——抽样检测进行了探讨和思考。围绕抽样方法,探讨了抽样环节、抽样过程以及各项注意要点。选取了5个代表性的检测项目,探讨了检测的特点以及检测对SPD质量监管的意义,并阐述了承担抽样检测的检测机构所应具备的资质和能力,以提升SPD行业整体质量。     

Hybrid Chemical Reaction Optimization Approach for Combined Economic Emission Short-term Hydrothermal Scheduling

—This article presents the hybridization of a newly developed, novel, and efficient chemical reaction optimization technique and differential evolution for solving a short-term hydrothermal scheduling problem. The main objective of the short-term scheduling is to schedule the hydro and thermal plants generation in such a way that minimizes the generation cost. However, due to strict government regulations on environmental protection, operation at minimum cost is no longer the only criterion for dispatching electrical power. The idea behind the environmentally constrained hydrothermal scheduling formulation is to estimate the optimal generation schedule of hydro and thermal generating units in such a manner that fuel cost and harmful emission levels are both simultaneously minimized for a given load demand. In this context, this article proposes a hybrid chemical reaction optimization and differential evolution approach for solving the multi-objective short-term combined economic emission scheduling problem. The effectiveness of the proposed hybrid chemical reaction optimization and differential evolution method is validated by carrying out extensive tests on two hydrothermal scheduling problems with incremental fuel-cost functions taking into account the valve-point loading effects. The result shows that the proposed algorithm improves the solution accuracy and reliability compared to other techniques.     

装车站液压系统漏油故障诊断系统

针对目前煤矿装车站液压系统漏油故障,通过对装车过程中液压系统数据采集、自动计算和分析,设计了PLC程序数据分析算法,可以自动检测漏油现象,判断漏油故障点,及时提醒装车站作业人员,降低现场设备的维护工作量,提高工作效率,减少漏油损失。     

大极板自动剥锌机阴极板装卸机构工作原理分析与应用

针对国内外锌冶炼行业技术发展现状,以北矿机电科技有限责任公司研制的新一代大极板自动剥锌机组为研究对象,首先介绍了大极板自动剥锌机组基本结构与工作流程,然后对阴极板自动装卸机构进行结构设计和工作过程分析,解决了进口剥锌机需要人工辅助钩板的弊端,实现了阴极板自动装卸彻底无人化操作,大幅提高了剥锌效率和设备的安全性可靠性,具有重要的工程应用指导意义。     

塑性流动下砂岩渗透率演化试验研究

为了研究剪切屈服后煤层顶板岩体在开采过程中渗透率的演化规律,进行了不同轴向应变下的围压循环加卸载渗透试验。当达到峰后轴向应力的90%时开始循环加卸载围压,分析剪切屈服后砂岩渗透率随围压、轴向应变的变化规律。结果表明:(1)随着围压、轴向应变的增大,砂岩的渗透率均呈现降低趋势;(2)随循环次数的增多,围压对渗透率的影响越来越小,渗透率恢复率升高;(3)随着轴向应变的增大,砂岩产生的塑性变形越大,由此围压对渗透率的影响减小,渗透率恢复到初始值的能力降低。最终得到剪切屈服后围压和渗透率的理论关系式,为预测巷道开挖过程中的涌水量提供一定的参考。     

2219铝合金动态压缩下应变率敏感性行为研究

为了研究2219铝合金的应变率敏感性行为,采用分离式霍普金森冲击压杆装置(SHPB)对两种热处理状态(T4态和T6态)2219铝合金进行了动态压缩实验,并利用金相显微镜(OM)和X射线衍射(XRD)对压缩后的试样进行了显微分析。研究发现两种热处理状态下材料应变率超过2000 s-1时,材料的流动应力显著下降,即出现显著的应变率软化行为。基于应变率敏感性行为随真实应变及应变率的二维等高线图,发现在高应变量、高应变率条件下材料表现出负应变率敏感性行为,流动应力随着应变量与应变率的提升而下降。通过理论计算及微观组织表征,发现温升软化和变形带导致的软化作用,是材料在高应变量、高应变率表现出负应变率敏感性行为的重要原因。     

Damage index of reinforced concrete members based on the energy dissipation capability degradation

Based on the estimation method of the energy dissipation capacity of reinforced concrete members under variable amplitude displacement cycles, the damage quantitative index of reinforced concrete members based on the energy dissipation capacity degradation is proposed. This index can establish a quantitative relationship with the energy dissipation capacity requirements and material parameters (yield force, yield displacement, and stirrup ratio). To understand the performance classification criteria of reinforced concrete members under variable amplitude displacement cycles based on the damage quantitative index, nine reinforced concrete members with different reinforcement conditions were tested. It was found that the reinforced concrete members can be classified as undergoing no damage (0 < D_k ≤ 0.3), mild damage (0.3 < D_k ≤ 0.6), moderate damage (0.6 < D_k ≤ 0.7), severe damage (0.7 < D_k ≤ 0.8), and destruction (0.8 < D_k ≤ 1), where the five performance states are based on the damage quantitative index. The performance classification criteria were verified by 18 flexural failure specimens in the Pacific Earthquake Engineering Research Center database.     

PVA-ECC徐变性能试验研究

基于7组聚乙烯醇纤维增强水泥基复合材料(PVA-ECC)试件的轴心受压徐变试验,研究了不同纤维掺量和加荷龄期条件下PVA-ECC的徐变性能.结果表明:在试验掺量范围内,纤维掺量越大,PVA-ECC的徐变能力越大;PVA-ECC的徐变随加荷龄期的延长而降低,晚龄期加载试件的徐变小于早龄期加载试件.结合已有混凝土徐变计算模型和本文试验结果,提出了估算PVA-ECC徐变的2种模型,其计算值与试验值吻合较好.     

低屈服点钢LYP100单调与循环拉伸试验研究

对47个LYP100低屈服点钢焊接试件进行单向拉伸和反复拉伸加载试验,研究其在不同加载制度下的应力-应变曲线、荷载-位移曲线、骨架曲线、破坏机理和延性特征.结果表明:试件横截面厚度是影响其耗能能力的重要因素,12mm试件的耗能能力明显优于6mm试件;焊接接头对试件的破坏有不利影响,带焊接接头的试件在循环加载作用下疲劳损伤累积效应显著,容易发生脆性破坏,延性变差;LYP100低屈服点钢与Q345钢、Q460钢焊接后,试件的强度提高,循环荷载作用下强度硬化现象明显,但是其延性变差.