华盛顿哥伦比亚特区合流制管网溢流污染治理及长效管控策略的工程经验分析

为长效控制华盛顿哥伦比亚特区合流制管网溢流(CSOs)污染问题,华盛顿哥伦比亚特区供排水局(WASA)以流域管控为单元,针对特区内各流域的本底情况和突出问题,按"灰色与绿色"、"地上与地下"、"分散与系统"相结合方式,制定长期有效的管控策略,并借助水力模型和监测手段进行实时监测与评估.结果表明,华盛顿哥伦比亚特区流域内...     

Combining Janus Separator and Organic Cathode for Dendrite-Free and High-Performance Na-Organic Batteries

The growth of Na-dendrites and the dissolution of organic cathodes are two major challenges that hinder the development of sodium-organic batteries (SOBs). Herein, a multifunctional Janus separator (h-BN@PP@C) by using an interfacial engineering strategy, is proposed to tackle the issues of SOBs. The carbon layer facing the organic cathode serves as a barrier to capture dissolved organic materials and enhance their utilization. Meanwhile, the h-BN layer facing the Na anode possesses high thermal conductivity and mechanical strength, which mitigates the occurrence of localized-temperature “hot spots” and promotes the formation of a NaF-enriched SEI, thereby suppressing dendrite growth. Consequently, the Janus separator enables a stable Na plating/stripping cycling for 1000 h at 3 mA cm⁻². Equipped with the Janus separator, organic cathodes including dibenzo[b,i]thianthrene-5,7,12,14-tetraone (DTT), pentacene-5,7,12,14-tetrone and Calix[4]quinone cathodes demonstrate high capacity and remarkable cycling performance. In particular, the DTT exhibits a bipolar co-reaction storage mechanism and achieves an ultrahigh capacity (≈342.6 mAh g⁻¹), long-term cycling stability (capacity decay rate of 0.15% per cycle over 550 cycles at 500 mA g⁻¹) and fast kinetics (1000 mA g⁻¹≈2.8 C). This study offers a straightforward, effective, and promising solution to address the challenges in SOBs.     

Preparation and application of composite EG/Ba(OH)2·8H2O form‐stable phase change material for solar thermal storage

Composite expended graphite (EG)/Ba(OH)₂·8H₂O form‐stable phase change material (PCM) is prepared with porous adsorption method in this study to solve the problem of the leakage risk in the application process based on barium hydroxide octahydrate. In addition, the thermal properties and stability have been measured and verified. Thermal conductivity of each group composite material was enhanced by about two to four times, while the addition has little negative effect on the other properties. With microscopic features being characterized by scanning electron microscope (SEM), the experimental result demonstrates that the composite material with 7 wt% of EG is optimal to be a saturated state between two phases. After the thermal cyclings of 100, 300, and 500 times, thermal properties did not change dramatically, which can be used as an ideal material for solar thermal storage system within finite thermal cyclings. In order to simulate the operating condition of solar energy or waste heat storage, the composite material was encapsulated in the heat storage unit with pipe bundle, and heat storage/release experiences were performed to test the performance of the material and hot water supply. The results indicate that the composite material is qualified to storage and release sufficient heat. The experimental data can provide necessary technical reference for engineering design and effect prediction in practical application.     

横山水库水质历史演变特征及其水文影响因素

为了解横山水库水质的变化情况,以横山水库1995-2020年长系列水文及水质监测资料为基础,分析其TP、NH3-N、CODMn、Chl-a等主要水质指标的变化趋势,以及水位、库容及年均降水量对TP变化趋势的影响.     

松辽盆地王府凹陷扶杨油层原油充注途径示踪

基于砂岩油藏充注模式,通过研究油藏内部原油成熟度的微细变化,依据成熟度参数的等值线可以示踪油藏充注的过程,成熟度参数等值线向前最为凸出的部位是石油运移/充注的优势途径。通过研究各项饱和烃成熟度参数,筛选出三环萜烷/17α(H)-C₃₀藿烷,Ts/(Ts+Tm),C₃₀重排藿烷/17α(H)-C₃₀藿烷,C₂₉甾烷ββ/(ββ+αα)等4项不受其他地质因素影响的参数,用于王府凹陷扶杨油层原油运移/充注途径的研究。通过17件扶杨油层原油的研究表明,所有参数均反映出王府凹陷原油成熟度分布规律一致,双32井为原油充注点,其离烃源灶最近;研究区内存在3条优势运移/充注途径,一是自双32井往北东方向充注至双26—双301—双31井区;二是自双32井处,经双38井,往北西西方向充注至长64—长11—长17井区;三是自双32井往北西方向充注至双231—双23井区。      

基于信息比对的电力系统监控信息全面巡视工作研究

介绍了调控工作中监控信息全面巡视工作的意义和遇到问题。引入数据比对理论,设计了对杭州市电网范围内的遥测和遥信信号的新的自动巡视策略,并基于My SQL后台数据库和VBA编程语言,搭建了智能巡视辅助决策系统,解决了监控信息全面巡视工作中的问题,提高了全面巡视工作的准确率和效率。实际运行情况表明,该辅助决策系统可以有效地提高电网运行监控的有效性和安全性。     

逆变侧换流变压器网侧接地故障对差动保护影响分析

特高压直流输电系统逆变侧换流变网侧单相接地故障后,网侧电压跌落可能会引发直流系统换相失败,有直流分量流入换流变压器绕组,使变压器铁芯磁通发生偏移,引起换流变饱和,产生故障性涌流,进而影响其安全稳定运行。针对逆变侧换流变网侧单相接地故障产生的故障性涌流问题,通过开关函数理论讨论了换流阀正常换相以及换相失败两种情况下网侧故障电流特征,分析了逆变侧网侧单相接地故障后换流变磁通的变化情况。在此基础上,研究了电流互感器饱和对换流变差动保护的影响。结果表明,换流变网侧区内故障情况下,网侧电流互感器饱和,使得换流变差动电流二次谐波含量超过门槛值,导致差动保护误闭锁。最后通过PSCAD/EMTDC仿真验证了分析的正确性。     

巨型工程机械子午线轮胎钢丝帘线应用研究

介绍巨型工程机械子午线轮胎常用的钢丝帘线,对其中几种帘线的性能进行检验,并用于实际生产。结果表明,钢丝帘线在压延、裁断和成型过程中工艺性能稳定,轮胎成品达到了设计要求,实际使用也取得了理想效果。建议开发生产更高强度、全渗透型简单化、开放式结构帘线并提高帘线的抗疲劳性能等。     

典型结构面分布型式节理岩体室内直剪试验研究

针对节理岩体变形破坏及抗剪强度参数确定问题,开展了5种包含两条节理的典型节理分布型式的节理岩体试样的室内直剪试验研究。试验结果表明节理岩体的破坏主要表现为节理控制的节理与岩桥间渐进搭接破坏;对比分析了试验得到的25条应力应变全过程曲线,提出了应力应变曲线分类方法,包括滑动型、屈服型、剪断型、脆断型、剪断复合型五种类型,揭示了不同类型曲线间的转化规律;对基于Lajtai岩桥破坏理论的强度准则进行试验验证,验证结果表明基于Lajtai岩桥破坏理论的强度准则计算得到抗剪强度偏低与试验结果相对误差较小(小于9%),可用于节理岩体综合抗剪强度计算。     

基于人体动静态特征融合的步态识别算法研究

提出一种融合步态运动中人体的静态特征和动态特征的步态识别算法:利用背景减除法得到人体轮廓,通过轮廓图像分段距离来表示静态特征;采用步态图像两脚的步幅和步频来表示动态特征;然后对两种特征进行加法融合、最小值融合、最大值融合和Choquet模糊积分融合。实验表明,两种特征融合后的性能优于基于单个特征步态识别算法,融合后识别率提高了5%到10%。