Results 31 to 40 of about 15,430 (207)
Ultrasound in Obstetrics &Gynecology, Volume 65, Issue 4, Page 456-461, April 2025.Abstract Objective To investigate the ongoing parvovirus B19 (B19V) outbreak among pregnant women in Germany and its connection to the coronavirus disease 2019 (COVID‐19) pandemic. Methods This retrospective cohort study analyzed anonymous data regarding serologically confirmed B19V infections during pregnancy between January 2014 and April 2024 across
J. Jiménez Cruz +14 more
wiley +1 more source
, 2019 为了估算有黏流情况下飞艇的轴向附加质量系数,采用计算流体动力学(CFD)技术计算了有黏流情况下椭球体在时变来流速度下的气动力随时间变化曲线,然后通过傅里叶分析法辨识得到了椭球体的..
刘智丽, 林献武
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Functional Ecology, Volume 39, Issue 4, Page 1096-1111, April 2025.Read the free Plain Language Summary for this article on the Journal blog. Abstract Many invasive plant species have demonstrated a better ability to tolerate and accumulate heavy metals than their co‐occurring native plants. Given the potential biological toxicity of heavy metals to phytopathogens, we postulated that heavy metal contamination could ...
Tiantian Lin +7 more
wiley +1 more source
A Kind of Large Load Light UAV Conceptual Design Platform and Manufacturing [PDF]
, 2016 近年来，无人机在军事领域的地位越来越重要；在民用领域，无人机的重要性也日益凸显。轻型无人机具有结构简单、体积较小、飞行高度低、飞行速度慢等特点，俗称“低小慢”航空器，可以利用较小的空间进行收放，起飞准备时间短，方便使用者利用有限的时间和空间进行工作。近几年来，随着飞控技术被不断重视，各方面科研力量都着手研制自己的飞控系统，同时各个拥有航空背景的高等学府也纷纷投入其中。作为高校，研制飞控系统需要有适合做飞行实验的飞行平台，此时，轻型无人机就可以发挥重要作用。因此 ...
黄荣
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Plant nutrient‐acquisition strategies contribute to species replacement during primary succession
Journal of Ecology, Volume 113, Issue 4, Page 988-1003, April 2025.Pioneer species Hippophae acquires phosphorus and nitrogen mainly by ‘mining’ and N2‐fixing strategies and thus dominates in the beginning of primary succession. As soil nutrient availability increases with the mobilization of apatite‐P and input of N‐rich plant residues, Hippophae' strategies become less efficient than Populus's scavenging strategies.
Xiao‐Long Li +12 more
wiley +1 more source
, 2018 微纳尺度颗粒(包括细胞、细菌、人工合成微纳颗粒、生物大分子等)的精确操控在生物、医学、材料和环境等领域有着至关重要的应用。惯性效应是近几年出现的能够实现颗粒高通量精确操控的一种新颖微流控方法。众多人工合成颗粒、生物颗粒等具有非球形形状,非球形颗粒的惯性迁移效应研究逐渐开始受到重视。在此,我们研究了柱状颗粒在两种不同宽高比通道下的迁移规律,发现柱状颗粒存在汇聚为矩形环状结构,进而迁移至稳定平衡位置的迁移过程。通过对柱状形颗粒与三种等效直径的球形颗粒的平衡位置进行比较 ...
胡国庆, 苏敬宏, 陈晓东
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Ultrasound in Obstetrics &Gynecology, Volume 65, Issue 3, Page 303-310, March 2025.ABSTRACT Objective Globally, one in four pregnant women is classified as overweight or obese, based on their prepregnancy body mass index (BMI). Obese pregnant women are at increased risk of adverse pregnancy outcomes and long‐term cardiovascular disease that occurs earlier in life.
M. Charakida +6 more
wiley +1 more source
, 2011 通过开展2类刚度差异较大的桩基础的离心机动力模型试验,系统地讨论柔性桩和刚性桩的地震反应差异,以及周围土体对桩体的不同作用效应。对于柔性桩,周围土体的作用主要体现在对桩的约束效应上;然而对于刚性桩,土体更大程度上对桩体施加附加惯性力的作用,以致桩筏基础的周期明显高于无土时的周期;针对柔性桩和刚性桩显著的地震反应差异,巧妙地提出用桩筏结构自振频率wp r界定两者的行为 ...
裴建良, 马亢
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Veterinary Dermatology, Volume 35, Issue 6, Page 595-604, December 2024.Background – Mycobacterium cell wall fraction (MCWF) is derived from nonpathogenic Mycobacterium phlei and is used as an immunomodulatory compound in clinical practice, yet its mode‐of‐action requires further research. Objective – To evaluate the host response to MCWF in canine peripheral blood mononuclear cells (PBMCs) by using enzyme‐linked ...
Robert Ward +9 more
wiley +1 more source
Efficient Simulation Methods for Reinforced Concrete Columns with Encased Steel in High-rise Building Structures [PDF]
, 2016 型钢混凝土柱在建筑结构中往往是主要的承重构件之一，使用合适的数值模型分析其力学性能对高层结构抗震分析有重要的意义。本文综述了目前文献中已有的低含钢率恢复力模型相关研究，分析了其理论、计算流程和算法，并在通用有限元软件OpenSees中编程实现。本文详细推导了模型中基本参数的确定方法，并用于模拟实际高层建筑结构中的型钢混凝土柱。首先，本文用恢复力模型模拟了单根型钢混凝土柱的试验，通过对比验证了模型的精度，研究了其计算效率。其次，本文将恢复力模型用于理想32层高层结构中的单排型钢混凝土构件静、动力分析中 ...
曾志弘
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