Results 41 to 50 of about 143,612 (165)
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
doaj
Home‐Based Versus In‐Hospital Care in Pediatrics: A Systematic Review of Cost‐Effectiveness Studies
World Medical &Health Policy, Volume 18, Issue 2, June 2026.ABSTRACT Home‐based care has emerged as a potential alternative to traditional hospital‐based care for children and adolescents worldwide. This systematic review aimed to systematically gather and critically assess the available evidence on the cost‐effectiveness of home‐based versus in‐hospital care for pediatric populations globally.
Luís Carlos Lopes‐Júnior +8 more
wiley +1 more source
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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Conservation Biology, Volume 40, Issue 3, June 2026.Abstract Achieving global conservation policy goals requires the ability to set and measure progress toward science‐based targets for biodiversity. The species threat abatement and restoration (STAR) metric was developed to enable actors to set science‐based targets for species.
Louise Mair +17 more
wiley +1 more source
, 2016 编辑部：有次下雨后乘坐飞机，登机时，发现发动机前有时会产生一道类似龙卷风的神秘气流，它们是怎么形成的呢？对飞机是否有危害呢？一名读者 发动机前为何会有“龙卷风”？ 在说其原因之前，咱们还是先来欣赏一下飞机发动机的杰作，一饱眼福。 “波音YC-14”，你这是在玩杂技吗？ 波音C ...
胡漫摘编
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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
doaj
Rare Metals, Volume 45, Issue 5, May 2026.ABSTRACT Environmental pollution across water, air, and soil systems poses escalating threats to human health and ecosystem stability, driven by heavy metals, persistent organic pollutants, particulate matter (PM), bioaerosols, and toxic gases. Conventional remediation technologies often suffer from limited selectivity, insufficient efficiency, and the
Junjie Qi +6 more
wiley +1 more source
, 2015 考虑叶片和塔架的动力耦合作用,建立了5 MW风机整体结构的有限元模型,计算其在随机风速下的动响应。为分析叶片和塔架的动力耦合对风机结构动响应的影响,计算比较了刚性支撑的叶片、简化的风机和整体风机3种模型在风载下的动响应位移和应力。计算结果表明:由于叶片和塔架的耦合作用,叶片的位移响应最大增加约20%,但是塔架的位移响应最大降低了约60%。文章还分析了叶片旋转过程中方位角对塔架位移响应的影响。在叶片的一个旋转周期内,塔架的响应幅值会有较大的波动 ...
陈伟民, 郭双喜
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Ultrasound in Obstetrics &Gynecology, Volume 67, Issue 5, Page 613-622, May 2026.ABSTRACT Objectives To evaluate the effect of aspirin on gestational age at delivery due to preterm pre‐eclampsia (PE) in women with chronic hypertension (CH), to assess the predictive performance of the Fetal Medicine Foundation (FMF) first‐trimester competing‐risks model for preterm PE in this high‐risk group and to evaluate how parity, previous PE ...
D. L. Rolnik +23 more
wiley +1 more source