Results 21 to 30 of about 2,915 (113)

基于思维进化和L-M法优化BP神经网络的SF6断路器触头电寿命评估

open access: yesGaoya dianqi, 2023
文中分析35 kV SF6断路器一相触头的动态电阻曲线的特点,提取出主触头接触行程、主触头电阻平均值、弧触头接触行程、弧触头电阻平均值和主触头分离时刻动态电阻极大值5个特征参数,分析得到随着烧蚀程度加深,主触头接触行程和弧触头接触行程减小,主触头电阻平均值、弧触头电阻平均值和主触头分离时刻动态电阻极大值增大。提出电寿命指示参数描述触头状态,采用数值表示法,1表示电寿命完好,0表示电寿命完结。以5个特征参数为输入,电寿命指示参数为输出,基于BP神经网络建立电寿命评估模型 ...
马飞越   +7 more
doaj  

Factors That Influenced Coping With COVID‐19 During the Pandemic in Botswana

open access: yesWorld Medical &Health Policy, Volume 18, Issue 1, March 2026.
ABSTRACT This paper forms part of the broader Global South study, Personal and Family Coping with COVID‐19 in the Global South, which examines psychosocial and behavioral responses to the COVID‐19 pandemic. In Sub‐Saharan Africa, the pandemic posed significant psychological, social, and economic challenges, with important implications for preparedness ...
Magen Mhaka‐Mutepfa   +3 more
wiley   +1 more source

Australian Teen Voices on Age Verification and Age Assurance Measures

open access: yesPolicy &Internet, Volume 17, Issue 4, December 2025.
ABSTRACT Age verification and age assurance technologies, including biometrics, facial recognition software and digital identification, have been explored as potential measures to restrict access of young people to social media and sexually explicit media (SEM), including pornography.
Giselle Woodley   +5 more
wiley   +1 more source

US Foreign Policy and the Gulf States: Changing Dynamics in a Multipolar World

open access: yesWorld Affairs, Volume 188, Issue 4, Winter 2025.
ABSTRACT This article focuses on US foreign policy toward the Gulf from Obama's Pivot to Asia to the initial period of the second Trump administration. It situates the role of the US within the broader context of the global energy transition and the Gulf states as geopolitical actors in a multipolar world order.
Steven Wright
wiley   +1 more source

More Complex Constrained Language? An Investigation on Nominal Complexity in Constrained Spoken English Varieties of ESL, EFL, and Interpreted English

open access: yesInternational Journal of Applied Linguistics, Volume 35, Issue 3, Page 1482-1494, August 2025.
ABSTRACT While previous research has established nominal complexity as a key indicator of grammatical complexity, its multi‐dimensional manifestation in constrained varieties remains underexplored. This study investigates the distribution of complex nominal structures in constrained spoken English varieties, specifically English as a Second Language ...
Jiaxin Chen, Yao Yao, Dechao Li
wiley   +1 more source

How Long‐Held Perceptions of Deservingness Continue to Shape Public Attitudes About Program Eligibility

open access: yesPolitics &Policy, Volume 53, Issue 3, June 2025.
ABSTRACT The literature has established that the politics of the welfare state are often shaped by perceptions of deservingness based on the behaviors and characteristics of target populations as well as their race and ethnicity. How are public attitudes affected when confronted with target populations along these two dimensions simultaneously?
Simon F. Haeder
wiley   +1 more source

弓网系统静态接触电阻特性研究

open access: yesGaoya dianqi, 2012
弓网良好接触是保障机车稳定受流的关键,合适的弓网接触压力是弓网稳定可靠受流的基础。笔者研究了不同接触压力、牵引电流条件下的弓网静态接触电阻,并得到了弓网接触电阻的数学表达式。研究结果表明:弓网静态时接触电阻随接触压力、牵引电流增大而减小,接触压力小于7080 N,接触电阻所接触压力的增加,接触电阻激剧减少;大于7080 N后,接触电阻随接触压力的变化不明显,近似恒定关系。
王万岗   +8 more
doaj  

Innovative Exploration of Urban Nature Education: The Mini Botanical Garden Concept 城市自然教育的创新探索:小微植物园实践

open access: yesIntegrative Conservation, Volume 4, Issue 1, Page 10-19, March 2025.
Brief summary: Urbanization is leading to “Nature‐deficit Disorder” that threatens children's health and the sustainable development of humanity. This study implements a new solution—the Mini Botanical Garden, which integrates some of the functions of botanical gardens into community green spaces to popularize nature education in the city.
Aoqi Zhang   +6 more
wiley   +1 more source

Can reducing learning costs improve public support for means‐tested benefit programs?

open access: yesPolicy Studies Journal, Volume 53, Issue 1, Page 135-157, February 2025.
Abstract This study investigates how efforts to reduce learning costs of means‐tested public benefit programs impact public support of these programs and perceived deservingness of program beneficiaries. Focusing on the Supplemental Nutrition Assistance Program (SNAP) in the United States, a well‐known means‐tested public benefit program, we integrate ...
Gregory Porumbescu   +2 more
wiley   +1 more source

考虑接触电压的风电机组接地网优化设计

open access: yesDianci bileiqi, 2013
为确保风电场电气设备和工作人员人身安全,接地设计需要有合格的接地电阻值、接触电压和跨步电压值。在接地电阻满足安全值的情况下,如果接地设计不合理,地面上还是可能产生超过允许值的接触电压和跨步电压。降低接触和跨步电压的一般方法是增设水平接地网和在地表铺设高阻率土壤层,但风电机组所处自然环境特殊,受地形限制,不易过多扩大接地网面积。在不增加接地网总长度的情况下采用不等间距法布置地网导体,或者改变地基与接地网的相对位置可显著降低地表最大接触电压,提高地网安全水平 ...
宋景博   +4 more
doaj  

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