Results 41 to 50 of about 7,536 (172)

Genetic Diversity and Phylogeographic Structure of the Edible Caterpillars of Gynanisa maja and Implications for the Sustainability of the Species in Namibia

open access: yesIntegrative Conservation, Volume 4, Issue 3, Page 405-415, September 2025.
Assessing the genetic diversity of edible insects harvested from the wild is a pre‐requisite for designing conservation and management policies. The caterpillars of Gynanisa maja (Saturniidae) are harvested in large numbers in mopane woodlands in southern Africa, where they represent a seasonal source of income and nutrition to many rural communities ...
Zwannda Nethavhani   +3 more
wiley   +1 more source

接地电阻影响因素的研究

open access: yesGaoya dianqi, 2003
利用复合接地网接地电阻的三维单元网络模型,研究了几种接地网的接地电阻值。在消耗同样的工程用料情况下,比较了各种接地体的优劣,并对影响接地电阻大小的参数(如主框和侧边辐射线长度、接地网埋深、接地导体直径等因素)作了对比。计算结果可以用来指导接地网的设计。
刘春, 何俊佳, 刘浔
doaj  

基于磁场分布特性的接地网腐蚀断点检测方法研究

open access: yesDianci bileiqi, 2021
变电站接地网腐蚀断点的缺陷对变电站造成潜在的安全隐患,然而目前能用于实际的接地网腐蚀检测系统十分缺乏,为了提高大型接地网导体腐蚀断点检测的效率和精度,使用了诊断接地网地表面电磁感应密度的方法。首先在对接地网磁场分布仿真计算的基础上研制了磁场信号激励源,并结合现场实际电磁干扰特征,研制了信号采集、处理、分析系统。然后利用该系统检测大型接地网地表面磁场分布,依据磁场分布特征和规律快速确定接地网导体的断点故障及部位。最后根据仿真计算分析、试验接地网实验测试和现场应用,表明了该方法诊断接地网断点的有效性和准确性。
张树亮   +6 more
doaj  

The Two Faces of Introgression in Conservation Biology 基因渗入在保育生物学中的双重面貌

open access: yesIntegrative Conservation, Volume 4, Issue 3, Page 339-344, September 2025.
Conservation biologist need to take into account the various aspects of introgression in their attempts to protect the species integrity and evolutionary potential of threatened species. To do so, they have to overcome the bias created by the Mayrian species concept that considers species as having distinct gene pools.
Harald Schneider, Charles H. Cannon
wiley   +1 more source

Exploring Challenges and Opportunities in International Healthcare Partnerships: A Thematic Analysis

open access: yesWorld Medical &Health Policy, Volume 17, Issue 3, Page 456-467, September 2025.
ABSTRACT In global health collaborations, countries of all development levels may seek international assistance, emphasizing trust and conflict resolution. However, existing frameworks lack sustainability metrics, governance, and evaluation criteria.
Salma Arabi   +2 more
wiley   +1 more source

Exploring the Direct and Indirect Relations of E‐Book Narration and Bilingual Parent–Child Talk to Children's Learning Outcomes in EFL Shared Reading

open access: yesInternational Journal of Applied Linguistics, Volume 35, Issue 3, Page 1134-1148, August 2025.
ABSTRACT E‐books, powered by multimedia and interactive features, are widely used to support young children's language and literacy development. This study examines the relations of e‐book narration and bilingual parent–child talk to children's learning during shared reading. Data from 121 English learners in China and their parents were analyzed using
Dandan Yang   +3 more
wiley   +1 more source

圆环地网与方形地网冲击特性对比仿真

open access: yesDianci bileiqi, 2013
为了更好的解决接地网散流、均压以及降阻问题,对圆环形接地网的均压特性及接地电阻进行了研究,并与传统的方形地网进行比较,采用电磁暂态仿真程序(ATP)对不形状的接地网,在雷电冲击作用下的电压大小进行仿真,以及对同一地网雷电流入地点不同时,入地点处的电压大小进行了仿真分析。结果分析表明:周长相同的圆环形地网与方形地网相比,圆环形地网的接地电阻比方形地网的小,并且雷电流入地点处的电压只有方形地网的一半左右,散流效果比方形地网好。在同跨度下,圆环地网的跨步电压也明显小于方形地网,均压效果好 ...
杨廷方, 张航, 陈智翔, 罗星辰
doaj  

Transformation of social‐ecological systems in the Songhua River Basin, Northeast China: Lessons for a more sustainable development

open access: yesPeople and Nature, Volume 7, Issue 7, Page 1749-1768, July 2025.
Abstract Social‐ecological systems (SES) are coupled systems formed by the intricate interactions between humans and nature. Our movement towards sustainable lifestyles requires a robust understanding of these interactions. Achieving a sustainable win‐win situation for both social and ecological systems, therefore, necessitates a sound scientific ...
Na Sa   +6 more
wiley   +1 more source

基于试验分析的变电站接地网冲击特性研究

open access: yesGaoya dianqi, 2016
为有效分析变电站接地网的冲击特性,提高变电站电气设备的运行可靠性和确保人身安全,文中以35 kV变电站用典型接地网为依托,基于量纲相似原理设计和定制了规则形状和不规则形状的两种接地网模型,通过模拟接地网导体变细、断裂和脱焊等典型故障,对接地网模型的冲击特性进行了试验研究。试验结果表明:接地网的冲击特性随冲击电流波形、注入点不同有较大差异,且规则接地网的暂态散流特性优于不规则接地网;对同一冲击电流注入点,冲击电流波形的波头时间越短,接地网的冲击接地电阻越大;冲击电流从接地网中心注入时 ...
苏磊   +4 more
doaj  

自动气象观测场站地网性能分析与研究

open access: yesDianci bileiqi, 2015
自动气象观测场站包含集成度较高且耐压能力较弱的电子设备,易因雷电过电压、故障电压等造成损坏。采用CDEGS软件对自动气象观测站两种不同布置形式地网的接地性能进行仿真分析,将地电位升、跨步电压以及接触电压仿真结果与理论计算值进行对比,得出两种地网仿真对比后接地性能的一般规律:地电位升由地网中心地带向地网边缘地带呈现逐渐降低的趋势且中心下降幅度较边缘大;跨步电压大小与接地体距离成反比,与接地系统网格间距成正比;接触电压由接地网边缘向中心地带逐渐降低;在地网面积相同的前提下,网格状地网地电位升 ...
郭在华   +5 more
doaj  

Home - About - Disclaimer - Privacy