Results 31 to 40 of about 24,308 (149)

一种由直流后备式熔断器和直流真空负荷开关构成的直流组合电器

open access: yesGaoya dianqi, 2015
提出了一种由直流后备式熔断器和直流真空负荷开关串联组成的直流组合电器,对其直流开断特性进行了仿真和实验研究。新型直流组合电器可完成直流电流的全范围开断:当开断额定电流和过载电流时,采用真空直流负荷开关利用人工电流过零法开断电流,此时后备式熔断器不动作;当开断大过载电流和短路电流时,采用后备式直流熔断器直接开断大电流,也可以将大电流限制至较低幅值再采用真空直流负荷开关进行分断。实验结果证明,该直流真空负荷开关可以在5 ms内成功开断200 A至1.7 k A的直流电流,直流后备式熔断器可以开断1.7 k ...
刘思远   +7 more
doaj  

Participation Disenchants: How Online Political Participation Decreases Online Political Efficacy in China

open access: yesRegulation &Governance, Volume 20, Issue 1, Page 35-63, January 2026.
ABSTRACT Existing literature largely agrees that authoritarian regimes establish channels for political participation to gather valuable information on citizens' anti‐regime sentiments and policy preferences and to supervise lower‐level bureaucrats and firms.
Anton Bogs
wiley   +1 more source

±800kV特高压直流工程直流滤波器设计研究

open access: yesGaoya dianqi, 2012
直流滤波器是特高压直流输电工程直流场重要成套设备之一,笔者在总结前期特高压直流输电工程系统研究结论的基础上,研究分析了+800 kV特高压直流输电工程直流滤波器设计需要考虑的关键问题,包括滤波器形式,直流侧谐振,要考虑的典型故障;介绍了用于计算直流滤波器典型故障的模型和方法。以云广+800 kV特高压直流输电工程为例,对直流侧谐振进行了校核,对直流滤波器设备暂态定值进行了计算。研究结果表明,云广±800 kV特高压直流输电工程直流滤波器设计是合理的,可满足直流系统安全可靠运行要求。
田邑安, 张万荣, 行鹏, 胡宇
doaj  

Video Assistant Referee(ndums): A Populist Weapon or Effective Tool to Stop Autocrats in Competitive Authoritarian Regimes in Latin America?

open access: yesLatin American Policy, Volume 16, Issue 4, December 2025.
ABSTRACT In recent years, video assistant referee systems have been increasingly used to correct unfair decisions in sports. Similarly, I argue that constitutional referendums play a corrective role in hybrid or competitive authoritarian regimes, where the electoral referee is biased and the government enjoys unfair advantages.
Muhammet Derviş Mete
wiley   +1 more source

直流转换开关及直流旁路开关运行要求及防跳回路设计

open access: yesGaoya dianqi, 2022
换流站直流转换开关及直流旁路开关的操作机构大多由交流断路器改造而来,其防跳回路按照固定开关于分闸状态的原则设计,并不能完全适应直流系统的运行要求。文章概述了直流转换开关及直流旁路开关的结构及原理,从直流系统运行要求、最大转换电流及转换失败要求两个方面,分析了直流转换开关及直流旁路开关的设备运行要求。基于配合保障直流系统可靠性和可用率的要求分析了常规直流转换开关及旁路开关防跳回路设计存在的不足,指出直流转换开关和旁路开关的防跳设计应遵从固定于合闸状态的原则,并给出了防跳回路的改进设计。
余爽   +6 more
doaj  

Bipartisan Failures: How Political Agendas Undermine Core Ethical Principles in Emergency Management

open access: yesPolitics &Policy, Volume 53, Issue 6, December 2025.
ABSTRACT This paper examines how political agendas across the ideological spectrum compromise ethical principles in emergency management in the United States. Through a literature review and comparative fact‐based scenario analysis, it demonstrates that both conservative and liberal governments have politicized disaster declarations, resource ...
Erik Xavier Wood
wiley   +1 more source

Effect of aspirin on maternal hemodynamics in Chinese women at high risk for preterm pre‐eclampsia: longitudinal study

open access: yesUltrasound in Obstetrics &Gynecology, Volume 66, Issue 5, Page 621-630, November 2025.
ABSTRACT Objectives To compare the maternal hemodynamics of Chinese women at low and at high risk for preterm pre‐eclampsia (PE) and assess the differences in hemodynamic parameters between high‐risk women with or without prophylactic aspirin. Methods This was a prospective longitudinal case–control study of 857 Chinese women with a singleton pregnancy
X. Wang   +11 more
wiley   +1 more source

±800 kV特高压直流输电工程直流滤波器设计研究

open access: yesGaoya dianqi, 2007
介绍了直流输电工程采用的直流滤波器的类型与构成,分析了±800 kV特高压直流输电工程换流器在直流侧产生的谐波的特点,并与±500 kV高压直流输电工程做了比较。以实际的±800 kV特高压直流输电工程为例,对换流器在直流线路上产生的等效谐波干扰电流进行了计算,对不同直流滤波器设置方案下的滤波效果进行了比较,并以计算结果为依据提出了较为合理的±800 kV特高压直流输电工程直流滤波器设置方案,为最终确定实际工程直流滤波器方案具有一定的参考作用。
张万荣, 任军辉, 王蔚华
doaj  

Beyond Motivation: Modeling the Predictive Role of L2 Pride in Informal Digital Learning of English

open access: yesInternational Journal of Applied Linguistics, Volume 35, Issue 4, Page 1938-1952, November 2025.
ABSTRACT This study investigates the role of second language (L2) pride—an understudied affective factor—in shaping learners’ language learning motivation and involvement with informal digital learning of English (IDLE). Drawing on questionnaire data from 1388 Chinese university EFL students, the study employs structural equation modeling to examine ...
Minlin Minny Zou   +3 more
wiley   +1 more source

Is “Neijuan” the Way to Achieve Early‐Career Teachers’ Well‐Being: A Perspective From the Relationship Among Foreign Language Teacher Well‐Being, Agency, and Identity

open access: yesInternational Journal of Applied Linguistics, Volume 35, Issue 4, Page 1927-1937, November 2025.
ABSTRACT “Neijuan” (translated as involution) has sparked increased interest in the development of foreign language teacher identity. However, research exploring neijuan's potential role in fostering identity development during early career stages has been insufficient.
Yanhua He   +2 more
wiley   +1 more source

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