Results 31 to 40 of about 1,812,492 (143)

真空断路器开断35kV并联电抗器的三相建模仿真与过电压抑制研究

open access: yesGaoya dianqi, 2017
为探究真空断路器开断35 kV并联电抗器时过电压产生机理和改进现有仿真模型的不足,笔者简单综述了真空断路器开断感性小电流的仿真研究现状,基于ATP-EMTP电磁暂态仿真软件,利用Fortran语言在MODELS模块中编写控制程序,建立40.5 kV真空断路器开断时电弧重燃三相模型,搭建了真空断路器开断35 kV并联电抗器三相仿真电路并考虑了断路器、三芯电缆三相间的寄生参数。在研究回路无任何保护情况下,断路器负载侧相间电压达到235 kV(7.1 p.u.),对地电压达到145 kV(4.4 p.u ...
彭庆军   +5 more
doaj  

Separation of racemic naproxen ester on cellulose-based(TA)chiral stationary phase(外消旋萘普生酯在纤维素衍生物手性固定相上的分离)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2002
采用高效液相色谱在纤维素三醋酸酯(CTA)手性柱上,对7种结构不同的外消旋萘普生酯进行了手性拆分.考察了流动相组成的改变以及外消旋萘普生酯的结构对手性分离的影响.实验结果表明:外消旋萘普生酯能在CTA手性柱上获得分离;外消旋萘普生酯与CTA手性固定相之间存在的强极性作用(主要是偶极-偶极作用)并不是手性识别的决定因素;支配手性拆分的主要因素是外消旋萘普生酯在CTA手性空腔中的体积大小适应性,尤其是立体结构的空间适应性是关键.
ZOULi(邹莉)   +4 more
doaj   +1 more source

Flexible, Robust Transparent Conductive Films With Excellent Electromagnetic Shielding Properties

open access: yesRare Metals, Volume 45, Issue 8, August 2026.
ABSTRACT Transparent conductive films (TCFs) are indispensable components for next‐generation wearable electronics, intelligent robots, and electromagnetic interference (EMI) shielding devices. However, the fabrication of conventional random metallic mesh suffers from an inherent trade‐off between “randomness and controllability”.
Shanghao Lu   +5 more
wiley   +1 more source

Spatial identification of areas suitable for other effective area‐based conservation measures in the European Union

open access: yesConservation Biology, Volume 40, Issue 4, August 2026.
Abstract Although significant biodiversity has been safeguarded by protected areas (PAs), biodiversity trends continue downward. Within the frameworks of the EU Biodiversity Strategy for 2030 and the new EU Restoration Regulation (2024), conserving critical biodiversity areas is essential.
George Kefalas   +14 more
wiley   +1 more source

Root economic space is associated with rhizosphere microbial divergence via root metabolite‐mediated pathways in degraded grasslands

open access: yesFunctional Ecology, Volume 40, Issue 7, Page 2068-2082, July 2026.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Grasslands worldwide are experiencing severe degradation due to overgrazing, climate change and anthropogenic disturbances, resulting in substantial declines in biodiversity and ecosystem functioning.
Xiaoqi Wang   +5 more
wiley   +1 more source

Simultaneous Generation of Topographic Models and Manning Roughness Coefficient Maps From Tri‐Stereoscopic Satellite Images: Application to the Huarmey River, Peru

open access: yesThe Photogrammetric Record, Volume 41, Issue 195, July‐September 2026.
Tri‐stereoscopic PeruSat‐1 imagery enables the simultaneous generation of 0.70 m‐resolution topography and spatially distributed Manning roughness maps, achieving 0.434 m vertical accuracy. Integrated into HEC‐RAS, these products provide consistent, high‐resolution inputs that improve hydraulic modelling and flood risk assessment in data‐scarce river ...
Jorge L. Miranda‐Pita   +3 more
wiley   +1 more source

35 kV并联补偿电容器组继电保护动作时过电压的分析及防护

open access: yesGaoya dianqi, 2017
为探究继电保护动作时,真空断路器开断35 kV并联电容器时过电压产生机理和改进现有仿真模型的不足,笔者简单综述了真空断路器开断电容器组的仿真研究现状,基于ATP-EMTP电磁暂态仿真软件,搭建了真空断路器投切35 kV电容器组的三相电路并考虑了三芯电缆、断路器三相间的耦合参数。模拟了继电保护动作时,真空断路器快速合—分闸电容器组的操作,并仿真了首开相重燃、两相同时重燃、母线对地电容瞬间变化等因素对投切电容器组过电压的影响。仿真结果表明:继电保护动作,母线对地电容发生瞬间性变化导致"虚拟截流 ...
司马文霞   +4 more
doaj  

Study on the spatio-temporal evolution characteristics and influencing factors of medical resource supply in the Yangtze River Delta region(长三角地区医疗卫生资源供给的时空演化特征及其影响因素)

open access: yesZhejiang Daxue xuebao. Lixue ban
Driven by the national strategies of health China and the integrated development of the Yangtze River Delta region, the supply capacity of health care resources has become an important indicator of the equalization of regional public facilities, and ...
陈玉娟(CHEN Yujuan)   +4 more
doaj   +1 more source

空间环境导致的藻类生物学效应

open access: yes, 1997
藻类空间生物学效应研究目前已从“发现效应”(第一阶段)转入到“揭示效应的分子机理”(第二阶段)的新阶段,涉及的研究层次包括种群、群体、个体、组织细胞和分子的各个方面 ...
胡章立,刘永定
core  

空间科学展望

open access: yes, 1996
一、空间科学 空间科学研究行星系统、恒星系统、星系、宇宙、以及生命物质等宇宙空间客体的结构和演化;以及在地球外空间进行生理学、生物学及微重力科学等精心设计的实验和研究。前者是在外层空间进行观测和测量,后者是将地面实验室的研究延伸到外层空间。当本世纪五十年代人造地球卫星被成功地发射到地外空间以后,人类的科学视野就极大地拓展了 ...
胡文瑞
core   +2 more sources

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