Results 21 to 30 of about 7,455 (179)

Individual asymmetric competition responses across multidimensional niches may enable coexistence of closely related species

open access: yesFunctional Ecology, Volume 39, Issue 8, Page 1957-1971, August 2025.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Many studies have focussed on niche differentiation at the population level to explain the coexistence of similar species. However, information on how individual‐level processes across multidimensional niches shape community dynamics and species coexistence, especially ...
Man Si   +8 more
wiley   +1 more source

Simulation Analysis and Optimization of Coach Seat and Passenger Coupling Impact System [PDF]

open access: yes, 2015
据相关资料表明,在客车碰撞所造成的人员伤亡中,因乘员与座椅之间的二次碰撞或座椅与车体相连部位的失效占了相当大的比例。为了提高我国客车在碰撞事故中对乘员的保护能力,客车座椅及其固定点强度的国家标准GB13057-2014目前已从推荐性标准升级为强制性实施标准。为了保证所设计的座椅能满足新法规要求,必须深入研究客车座椅及其固定支架的结构变形及乘员在碰撞过程中的伤害情况。 汽车碰撞过程是一个瞬间的复杂的物理变形过程,它包含了几何非线性,材料弹塑性变形非线性和零部件间复杂的接触非线性等特征 ...
卢琳兆
core  

使用应变模态和遗传算法的有限元模型修正方法 [PDF]

open access: yes, 2018
提出了采用应变模态置信度为待修正响应特征的有限元模型修正方法。应变模态置信度是评价有限元仿真与试验测试结果相关性的方法,可以为模型修正提供全局的频率误差信息和局部的应变相关性信息。首先,介绍了应变模态和有限元模型修正的相关理论方法;然后,以某航空加筋壁板结构为对象,通过仿真分析和\"仿真试验\"获得结构的应变模态频率以及对应的应变振型,进一步计算频率误差和应变模态置信度误差;最后,基于两种误差构造模型修正的目标函数,采用遗传算法对目标函数进行优化,修正结构中的待修正参数,并将修正后参数代入模型 ...
展铭, 岳林, 张保强, 郭勤涛
core   +1 more source

Research Progress and Forensic Application of Human Vascular Finite Element Modeling and Biomechanics [PDF]

open access: yes, 2023
The finite element method (FEM) is a mathematical method for obtaining approximate solutions to a wide variety of engineering problems. With the development of computer technology, it is gradually applied to the study of biomechanics of human body.
Yong ZENG, Dong-hua ZOU, Ying FAN, Qing XU, Lu-yang TAO, Yi-jiu CHEN, Zheng-dong LI
core   +1 more source

Multiple components of plant diversity loss determine herbivore phylogenetic diversity in a subtropical forest experiment

open access: yesJournal of Ecology, Volume 107, Issue 6, Page 2697-2712, November 2019., 2019
We integrated multiple components of plant and herbivore diversity to unravel the linkages that drive biodiversity relationships and determine the consequences of biodiversity loss across trophic levels. Our study suggests that lepidopteran phylogenetic diversity is significantly affected by plant species loss when basic splits in the evolutionary ...
Ming‐Qiang Wang   +18 more
wiley   +1 more source

Behavior of a Flexspline in Harmonic Drive [PDF]

open access: yes, 1900
谐波齿轮传动是利用柔性工作构件的弹性变形波进行运动或者动力传递的一种新型传动方式,因其具有体积小、重量轻、精度高、单级传动比大、承载能力高等诸多优点,在航空航天、机器人、数控机床等领域得到了广泛的应用。柔轮作为谐波齿轮传动的关键构件很大程度上影响了谐波齿轮传动的承载能力、使用寿命等。柔轮为弹性薄壁件,在交变载荷作用下易导致齿面磨损和疲劳断裂。柔轮强度、变形与应力分析对谐波齿轮传动过程中的疲劳断裂评估及传动性能研究具有重要的意义。 本文首先根据已知参数、实际工况和谐波齿轮传动啮合参数选取原则 ...
刘淳剑
core  

Evaluating use of two‐step International Ovarian Tumor Analysis strategy to classify adnexal masses identified in pregnancy: pilot study

open access: yesUltrasound in Obstetrics &Gynecology, Volume 64, Issue 6, Page 808-817, December 2024.
ABSTRACT Objectives The primary aim was to validate the International Ovarian Tumor Analysis (IOTA) benign simple descriptors (BDs) followed by the Assessment of Different NEoplasias in the adneXa (ADNEX) model, if BDs cannot be applied, in a two‐step strategy to classify adnexal masses identified during pregnancy. The secondary aim was to describe the
J. Barcroft   +8 more
wiley   +1 more source

International clinical practice recommendations on the definition, diagnosis, assessment, intervention, and psychosocial aspects of developmental coordination disorder – Chinese (Mandarin) translation

open access: yesDevelopmental Medicine &Child Neurology, Volume 61, Issue 3, Page E1-E35, March 2019., 2019
目的 本国际临床指南由欧洲残疾儿童学会(the European Academy of Childhood Disability,EACD)牵头制定,旨在解决发育性协调障碍(developmental coordination disorder,DCD)的定义、诊断、评估、干预以及与社会心理方面的临床应用关键问题。 方法 本指南针对五个领域的关键问题,通过文献综述和专家团队的正式讨论达成共识。为保证指南的循证基础,以“机制”、“评估”和“干预”为检索词, 对2012年更新以来提出的最新建议以及新增的“社会心理问题”和“青少年/成人”为检索词进行检索。根据牛津大学循证医学中心证据等级 (证据水平 [level of evidence, LOE]1–4) 将结果进行分类,最终转化为指南建议。并由国际 ...
Jing Hua   +6 more
wiley   +1 more source

Design and Simulation of Contact Fatigue Testing System of Flexspline and Circular Spline in Harmonic Drive [PDF]

open access: yes, 2016
谐波齿轮传动是随着空间技术的发展而诞生的一种新型传动方式,其工作原理是利用柔轮的弹性变形波来实现运动或者动力传递,因其具有结构简单、传动精度高、传动比大等诸多优点,在航空、航天、机器人等领域得到了广泛应用。在谐波齿轮传动过程中,柔轮的运动情况比较复杂,作为弹性薄壁构件需承载交变应力,容易造成齿面磨损和疲劳断裂。因此,建立合适的模型对谐波齿轮传动过程中柔轮的错齿运动进行模拟分析具有重要意义。 本文首先针对谐波齿轮传动过程中柔轮的错齿运动设计了一种新的接触疲劳试验装置 ...
吴泽林
core  

A new dawn? Population baselines of snow leopards and other mammals of the Kishtwar High Altitude National Park, India 新的曙光?印度基什特瓦尔高海拔国家公园雪豹和其他哺乳动物的种群基线

open access: yesIntegrative Conservation, Volume 3, Issue 3, Page 271-280, September 2024.
The Greater Himalayas in India, of which Kishtwar High Altitude National Park (KHANP) is a part, harbours potential snow leopard habitat. We sampled three catchments within the Dachhan region of KHANP using 44 cameras and identified four unique snow leopard individuals across 14 detections in nine camera locations.
Munib Khanyari   +8 more
wiley   +1 more source

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