Results 31 to 40 of about 11,890 (118)
Gaoya dianqi, 2017 为了了解大电网末端风电机组故障穿越特性,文中分析了高渗透率风力发电大电网末端电网特性及风机运行特性。结合相应的检测标准及要求,探讨了大电网末端风电并网出现的故障特性,研究了直驱及双馈风电机组故障穿越关键技术及控制策略;结合仿真及实际检测,研究了大电网末端直驱风力发电机高电压穿越能力、双馈机组低电压穿越的可行性,提出了风电机组故障穿越的隐患,为大电网稳定运行提供了依据。
李晖 +6 more
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Dianci bileiqi, 2022 大量风机控制和电力变换设备集中布置于风机塔筒底部,易遭受雷电反击过电压而损坏。建立了考虑风机钢筋混凝土基础自然接地作用的雷击瞬态模型,采用频域矩量法进行求解,通过傅里叶反变换获得设备安装位置的时域瞬态过电压波形和冲击阻抗。计算结果表明,考虑混凝土中的钢筋能显著降低风机雷电冲击接地电阻和塔筒底部电位抬升,在高土壤电阻地区影响更加明显;风机承台中的钢筋散流作用明显,考虑承台钢筋时风机冲击接地电阻和塔筒底部电位升明显减小,随着垂直桩基数量的增加,风机冲击接地电阻值和塔筒电位升进一步降低 ...
孙通 +8 more
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Integrative Conservation, Volume 4, Issue 4, Page 695-705, December 2025.The Next Jane program from Roots & Shoots was found effective for the conservation leadership improvement even though the participants attended it with different motivations. The development of conservation leadership traits was facilitated by skills development, a supportive environment, and reflective action.
Zhang Zekun, Chen Jin, Gu Siqi, He He
wiley +1 more source
Uncovering Multidimensional Determinants of Household Extreme Poverty in Southwest Papua, Indonesia
Poverty &Public Policy, Volume 17, Issue 4, December 2025.ABSTRACT This study examines the multidimensional determinants of extreme poverty among households in Southwest Papua, Indonesia, with the aim of identifying critical factors at the household level. The Study utilizes quantitative methods an analytical‐descriptive research design, including using logistic regression analysis on data from the 2023 ...
Sitti Aminah +9 more
wiley +1 more source
Gaoya dianqi, 2015 文中研究了当今世界重点风电市场区域的风电场/风力发电机组接入电网技术规定,归纳并分析了风力发电机组设计所需要考虑的风电接入电网技术要求,如有功功率控制、无功功率控制、低电压穿越、高电压穿越、电网适应性、电能质量;同时以风电机组低电压穿越特性为案例,重点探讨了3种主流风电机组低电压穿越能力与电网之间的相互影响,以及各类风力发电机组低电压穿越特性的基本解决思路,对风电场运营部门和电网调度部门有一定的参考价值。
郑翔宇 +5 more
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Ultrasound in Obstetrics &Gynecology, Volume 66, Issue 6, Page 706-715, December 2025.ABSTRACT Objective To evaluate the use of twin vs singleton growth charts for detecting small‐for‐gestational‐age (SGA) twins at risk of adverse neonatal outcomes. Methods MEDLINE, EMBASE, CINAHL, Cochrane and Scopus databases were searched electronically from inception to May 2024.
S. Sorrenti +9 more
wiley +1 more source
Gaoya dianqi, 2016 随着中国风力发电的比重及机组容量的不断增大,机组一旦发生故障,不仅影响风电场自身的安全,而且对电网的稳定运行造成重大影响。故障分析与智能诊断技术是降低大型风力发电机组故障率与运维费用的主要手段之一。文中详细分析了风力发电机组主要部件的故障,在对风力发电机组状态监测和故障诊断技术深入研究的基础上,提出了基于小波包和BP神经网络的智能诊断方法,以此开发了风力发电机组状态监测与故障诊断系统,通过系统在大型风力发电场的成功应用,验证了其对风电机组故障诊断的有效性。
董开松, 李涛涛, 尹浩霖
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World Medical &Health Policy, Volume 17, Issue 4, Page 823-830, December 2025.ABSTRACT Sepsis is a leading cause of mortality in the United States, with over 350,000 deaths annually, yet the contribution of neighborhood‐level social determinants of health (SDoH) remains underexplored. We conducted a retrospective analysis of 4.4 million hospitalized patients with sepsis, identified using ICD‐10 codes, leveraging de‐identified ...
Ahad Khaleghi Ardabili +3 more
wiley +1 more source
Dianci bileiqi, 2020 通过建立风机叶片遭受雷击时下行先导发展的物理模型,研究雷击风机叶片背景电势。依据临界长度判据描述叶片上行先导起始过程,研究临界背景电势变化时静止叶片上行先导起始情况,并分析旋转叶片上行先导起始时刻背景电势。基于叶片静止、旋转两种状态与背景电势分布,对风机不同条件下的叶片引雷能力进行评估。研究表明,若雷电情况与大气条件恒定,临界背景电势不变,临界背景电势变化将影响静止叶片上行先导的起始;当叶片转速一定,旋转叶片上行先导起始时刻背景电势取决于临界背景电势;伴随叶片角度与接闪器半径的增大,叶片引雷能力减弱 ...
雷宇航, 蔡国伟, 潘超
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Gaoya dianqi, 2022 叶片是风电机组的重要组成部分，承担着捕获风能的重要功能，一旦损伤必然导致风机停机，对其进行状态监测十分必要。对风机叶片的监测主要采用无损检测技术，传统方法大都基于电子测量原理，具有抗电磁干扰能力差、无法实现分布式测量等缺点。文中在对比传统无损检测技术灵敏度、效率、抗干扰能力等指标的基础上，重点分析和研究了光纤传感技术用于风机叶片监测的现状。从测量原理、传感器结构、应用实施方法、监测效果等方面，分析了FBG、BOTDA、OFDR以及干涉型光纤传感技术的研究进展 ...
吕安强, 魏伦
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