Results 11 to 20 of about 13,042 (158)
水电科技, 2019 考虑到架空线周围存在准静态电磁场，文章利用电磁场理论进行非接触式故障选线。采用以镜像法为基础的等效电荷法建立架空线周围电磁场数学模型，分析了故障前后线路下方电磁场与n次谐波零序电压和零序电流的关系。通过比较各次谐波对电磁场的影响程度，选取架空线下方5次零序谐波电磁场进行故障选线。当线路发生单相接地故障时，与非故障线路相比较，故障线路下方5次零序谐波电场和磁场的幅值和相位均发生明显改变。通过提取故障特征，可以实现小电流接地系统的故障选线。最后利用MATLAB软件进行电磁场仿真，仿真验证了该选线方法的可行性。
亚彩 王
core +3 more sources
水电科技, 2023 文章讨论了处理10kV配电线路单相接地故障的关键措施。首先，快速故障定位利用红外热像仪和故障指示器等技术，迅速准确地定位故障点。其次，故障隔离与恢复通过操作断路器和隔离开关，将故障区域与其他正常区域分隔开，并恢复供电系统的正常运行。最后，故障分析与预防通过深入分析故障原因并制定相应预防措施，减少故障发生频率和影响范围。综合运用这些措施，可以提高故障处理效率和可靠性，确保供电系统的稳定运行，为用户提供可靠的电力供应。
亦俊 王
semanticscholar +1 more source
智能城市应用, 2022 10kV配电线路单相接地故障是配网调度运行中最常见的故障形式之一,严重影响电网安全?生活和生产用电?为了有效的进行故障隔离?线路复电,就要打破传统的处置方式,寻找新兴的?科学的途径?文章结合云南电网配电自动化技术的特点,充分利用配电自动化开关的远方遥控功能,有效地提高了10kV配电线路单相接地故障隔离?线路复电的速度?
小波 叶
semanticscholar +1 more source
水电科技, 2022 本文针对高压单芯电力电缆金属护套接地进行了原理分析，接地方式错误将造成供电事故进行了阐述，实际工程中几种接地方式进行了说明，不同工程条件的高压单芯电缆接地应选用相对应的接地方式，此文列举工程实例进行具体计算分析，说明高压单芯电力电缆金属护套接地方式选用依据。
鑫东 张 +4 more
semanticscholar +1 more source
Se pu = Chinese journal of chromatography, 2021 食品接触材料中添加剂残留量的测定为食品接触材料从源头进行安全监管具有重要意义。然而目前的大多数研究只针对食品接触材料中有害物迁移量的测定,对于食品接触材料中有害物含量的测定方法仅局限于残留单体、低聚体、重金属,以及邻苯二甲酸酯类、双酚类化合物等环境污染物,对食品接触材料中添加剂残留量的测定较少。该研究系统地优化了样品前处理过程及仪器分析中影响8种添加剂分析准确度与响应灵敏度的各主要因素,建立了超高效液相色谱同时测定聚乙烯材料中8种添加剂的定量分析方法。聚乙烯样品冷冻研磨后,取2.0 ...
Yun-Biao Ling +5 more
semanticscholar +1 more source
Journal of Ecology, Volume 111, Issue 12, Page 2733-2749, December 2023., 2023 Our results indicate that defoliation and fertilisation, two common grassland perturbations, have contrasting impacts on root traits of grassland plant species, with direct and indirect short‐term consequences for a wide range of soil abiotic and biotic properties that underpin ecosystem functioning.
Yan Liu +2 more
wiley +1 more source
Family Process, Volume 62, Issue 3, Page 1114-1133, September 2023., 2023 Abstract This longitudinal investigation evaluated parental cultural socialization practices as a central mechanism by which parents' cultural values influence developmental outcomes in ethnic–racial minority children. Drawing on a sample of 129 Latina mothers and their children (48.1% daughters and 51.9% sons), path analyses evaluated hypothesized ...
Duyen T. Trang, Tuppett M. Yates
wiley +1 more source
生态环境与保护, 2020 研究建立了液液萃取-气相色谱质谱法测定地表水中松节油的方法。用二氯甲烷萃取水样中的松节油,氮吹浓缩后进行色谱分离,松节油的主要成分分离度达1.5以上,松节油在给定范围内线性关系良好,相关系数均在0.999以上,最低检测浓度可达0.016μg/L；对不同浓度的样品各进行了平行7次测定,回收率在82.4%~101%之间,相对标准偏差为4.9%~7.6%,表明分析方法的准确度和精密度良好。水样萃取液直接定容分析,10.0μg/L水样萃取后直接定容分析的回收率在89.0%~107%之间,平均回收率高达94.5%,
阳华 张, 小军 陈
semanticscholar +1 more source
Family Process, Volume 62, Issue 3, Page 1055-1074, September 2023., 2023 Abstract Multifamily therapy (MFT) for adolescent eating disorders (ED) is anchored in systemic theory and family therapy, but two conceptual and practical paths have emerged from this common framework. The first one, called ED‐focused MFT, is centered on behavioral change and weight gain in the early stages of treatment, while the second, known as ...
Solange Cook‐Darzens, Jeanne Duclos
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Conservation Biology, Volume 37, Issue 4, August 2023., 2023 Abstract Internet trade is increasingly recognized as a dispersal pathway of non‐native plant species that is difficult to monitor. We sought to identify non‐native flora present in the Chinese online market, the largest e‐commerce market globally, and to decipher the effect of existing trade regulations, among other variables, on e‐trading patterns ...
Achyut Kumar Banerjee +8 more
wiley +1 more source