Results 31 to 40 of about 5,641 (169)

强风作用下复合空心绝缘子的电场计算

open access: yesGaoya dianqi, 2020
高压断路器进出线的复合空心绝缘子主体长约8~10 m,弹性模量远小于瓷绝缘子。复合空心绝缘子在强风下会产生风偏,风偏量受风速大小和工作自身弹性模量影响。大幅风偏是否会引起复合空心绝缘子内外电场强度的畸变,劣化内外绝缘鲜有研究。由于高压复合空心绝缘子成本高,投运时间短,退运下来的样品较少。文中采用有限元分析的方法模拟强风工况,进行电场计算。针对750 kV断路器复合空心绝缘子在强风下振动的1阶模态振型,计算绝缘关键区域的电场强度,阐明风偏对接地屏蔽电极附近的电场畸变的危害最大,并给出了风速阈值 ...
张楠   +7 more
doaj  

典型高压绝缘子串风荷载体型系数的试验研究

open access: yesGaoya dianqi, 2022
随着中国输电网电压等级的逐渐提高,对线路绝缘的要求也在提高。高压绝缘子串往更长、联数更多的方向在发展。绝缘子串的风荷载也随之增大。更易发生风偏和风振的现象。文中通过风洞试验,采用测力天平技术,对目前南方电网常用的两种玻璃绝缘子和一种伞形复合绝缘子的体型系数开展了深入研究。系统考察了不同湍流度、风速、风偏角、风攻角作用下单联及双联绝缘子的体型系数的变化规律和影响因素。试验表明,湍流度对体型系数影响不大;单联绝缘子体型系数随风速的增大而逐渐稳定在0.8~0.9之间;风偏角下体型系数有显著变化 ...
张志强   +5 more
doaj  

Profiles of parental reflective functioning and mind‐mindedness in first‐time parents of 4‐month‐old infants

open access: yesInfant Mental Health Journal: Infancy and Early Childhood, Volume 46, Issue 6, Page 870-885, November 2025.
Abstract Profiles of parental reflective functioning (PRF) may offer valuable insights into individual differences in PRF. Previous studies have identified PRF profiles; however, further validation is needed. This study aimed to investigate the convergent validity of the identified PRF profiles by examining their association with a related measure of ...
Eva Back Madsen   +6 more
wiley   +1 more source

110kV、220kV大风区防风偏复合绝缘子

open access: yesDianci bileiqi, 2012
针对新疆110 kV、220 kV架空线路引流跳线在大风区特殊地段发生风偏闪络问题,介绍一种适宜于大风区使用的110 kV、220 kV防风偏复合绝缘子研制、设计情况及生产工艺的控制过程。该形式的防风偏复合绝缘子风偏摆动有限,有效控制了导线与杆塔的空气间隙,解决了大风区引流跳线风偏闪络问题,其连接方式安装可靠,具有通用性,还有利于已运行线路的技改。
马钢, 谢金华
doaj  

The relationship between Indian Ocean SSTA and winter climate over Eastern China(印度洋海温异常与我国东部冬季气候的关系)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2014
利用1960~2004年NCEP/NCAR全球再分析资料、SMIP2海温资料和我国160站逐月降水和气温观测资料,考虑到大气在从低纬到中高纬地区的能量传播的桥梁作用,首先对冬季印度洋海温距平场与同期北半球500 hPa位势高度距平场进行奇异值分解(SVD),然后分析印度洋海温异常与我国冬季气温和降水的关系.研究结果表明,冬季印度洋海温距平场第1奇异向量(SVD1)是全区一致的单极型分布形势,与我国冬季气温和东南地区降水的相关性非常显著.当冬季印度洋海温距平场第1奇异向量处于正位相时,印度洋海温异常偏暖 ...
CHENGHuiping(程慧萍)   +3 more
doaj   +1 more source

Correlation between fall risk and Traditional Chinese Medicine constitution of inpatients (住院患者跌倒风险与中医体质的相关性)

open access: yes中西医结合护理, 2021
Objective To explore the relationship between fall risk and Traditional Chinese Medicine (TCM) constitution of inpatients, and provide reference for reducing the occurrence of fall risk among inpatients.
WANG Bei (王蓓)   +6 more
doaj   +1 more source

Reproductive outcome after frozen embryo transfer with hormone replacement therapy according to luteal‐phase support protocol: systematic review and network meta‐analysis of randomized controlled trials

open access: yesUltrasound in Obstetrics &Gynecology, Volume 66, Issue 4, Page 422-432, October 2025.
ABSTRACT Objective To compare reproductive outcome between luteal‐phase support (LPS) protocols for frozen embryo transfer (FET) cycles with hormone replacement therapy (HRT). Methods A search was conducted in MEDLINE, Scopus, LILACS, EMBASE, Scielo.br, PROSPERO, CINAHL, PsycINFO, AMED, ClinicalTrials.gov, ICTRP, the Cochrane Library and conference ...
A. Etrusco   +11 more
wiley   +1 more source

盘形悬式瓷绝缘子在多刚体模型下的风偏应力分析

open access: yesDianci bileiqi, 2021
分析模拟盘形悬式瓷绝缘子串风偏运行时承受的应力大小可预防风偏闪络事故的发生。对此采用ANSYS Fluent计算流体动力学(CFD)软件,建立了基于RNG k-ε湍流模型的绝缘子串-导线三维模型并进行分析。首先计算出刚体与多刚体模型在多种风速下受到的von-Mises等效应力情况,并将两者与受力公式的计算结果进行对比分析。为进一步研究绝缘子串上不同位置的受力,又模拟并比较了多刚体模型在不同风速时相应位置的受力大小。结果表明,在风速大于30 m/s时,多刚体模型由于考虑风偏过程中各绝缘子之间的定点转动现象,
孟婧, 陈炯, 毕祥宜
doaj  

Preliminany analysis of the quasi-biennial oscillation and Zhejiang typhoon(赤道平流层纬向风的准2年振荡与浙江台风的初步研究)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2001
通过研究赤道平流层纬向风的准2年振荡(QBO)和浙江台风的关系,指出:浙江台风多发生在赤道平流层纬向风的东西风转向时期;在赤道平流层QBO为西风年时,浙江发生台风的总天数较多;在赤道平流层QBO的西风时段内发生台风的总个数和总天数都较多.在东风时段,每个台风的生命史较长.厄尔尼诺和拉尼娜使当年浙江台风的总天数偏少.厄尔尼诺年使浙江台风的生命史较长,而拉尼娜则相反.
TIANRong-xiang(田荣湘)
doaj   +1 more source

中风病的中医康复治疗浅识 [PDF]

open access: yes, 2003
本文提出中风病在生命体征稳定、神志清楚 ,神经功能不再恶化后 4 8~ 72小时就应开始康复治疗 ,病情稳定、一般状况好转 ,即可进行全面系统的康复治疗 ...
吕崇山
core  

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