Results 21 to 30 of about 5,317 (119)

On the Damage Tolerance of Diffusion Bonded Titanium–Aluminum Phase Biomimetic Composites

open access: yesRare Metals, Volume 45, Issue 2, February 2026.
ABSTRACT The biomimetic design principles of natural structures involve the strategic integration of stiff and compliant phases to synergistically enhance strength and toughness. Its evolutionary refined natural armor, characterized by a specialized microarchitecture, enables superior damage tolerance.
Shuai Tong   +10 more
wiley   +1 more source

Janus Nanofiber‐Architected Moisture‐Enabled Power Generator for Intelligent Sensing and Neuromorphic Application

open access: yesRare Metals, Volume 45, Issue 1, January 2026.
ABSTRACT Moist‐electric generators (MEGs) harness energy from ubiquitous ambient humidity, which has emerged as a promising way to collect energy irrespective of location and time. This study presents a high‐performance MEG employing a bilayer Janus nanofiber membrane: a hydrophilic layer (lithium chloride/citric acid/polyvinyl alcohol) for enhanced ...
Peng Chen   +7 more
wiley   +1 more source

A Comparison of the Effects of Habitat Type and Human Influence on Occupancy of Freshwater Turtles in the Mississippi Embayment 栖息地类型与人类影响对密西西比湾淡水龟分布影响的比较

open access: yesWildlife Letters, Volume 3, Issue 2, Page 46-55, June 2025.
Pond and riverine turtles respond to land‐use in similar ways being sensitive to increased exposure to roads but resilient to agriculture. ABSTRACT Freshwater turtles are highly diverse in the southeastern United States, yet few studies document how diversity is distributed in agricultural and rural landscapes.
Rowland Fournier   +7 more
wiley   +1 more source

Understanding consumers to inform market interventions for Singapore's shark fin trade

open access: yesPeople and Nature, Volume 6, Issue 2, Page 733-748, April 2024.
Abstract Sharks, rays and their cartilaginous relatives (Class Chondrichthyes, herein ‘sharks’) are among the world's most threatened species groups, primarily due to overfishing, which in turn is driven by complex market forces including demand for fins.
Christina Choy   +2 more
wiley   +1 more source

GaAlAS DH激光器若干参数的测量和分析 附视频

open access: yesTongxin xuebao, 1981
本文扼要介绍了GaAlAs DH激光器若干参数的测量方法和测试结果。在实验的基础上,就偏振特性、伏安特性、瞬态特性等问题进行了较详细的定性分析。解释了一些现象,提出了一些看法。主要结果如下:偏振特性更能反映自然解理腔面GaAlAs DH激光器的本质,因而偏振好坏可能成为这种激光器好坏的一个重要判据。正向导通电压和激光器的峰值波长有关;反向击穿电压可能和作用区的宽度有关。“正、反向都通但仍能发光”的器件,可以用加反偏压的方法治好。在偏振好的器件上,仍能观察到张弛振荡、尖峰效应、低频阻尼振荡、自脉动和顶部 ...
单振国
doaj  

风电集群接入柔直互联多区域协同调频策略 [PDF]

open access: yes全球能源互联网, 2019
由于柔直电网“隔离”了频率信号,互联多区域协同调频问题亟待研究。现有研究大多利用换流站的下垂控制以及直流电压偏差实现频率信号的传递,但忽略了风电集群接入后由风电功率正常波动引起的直流电压偏差干扰,可能导致风电集群在无需调频时频繁地调整出力。对此,提出了基于直流电压偏差及其特征量的多区域协同调频策略,分别针对电网频率偏移和风电功率波动两种场景提取直流电压偏差特征量,包含电压变化量、电压变化率和滤波后的电压分量幅值3个特征,并基于二者的差异设置换流站启动下垂控制的判据。仿真结果验证了所提方法的有效性。
崔阳   +5 more
doaj   +1 more source

十字形PEC短柱偏压性能及承载力计算方法研究

open access: yesJianzhu Gangjiegou Jinzhan
采用有限元模拟和理论分析相结合的方法,研究了十字形PEC短柱的偏压力学性能并推导出其偏压承载力计算公式。首先利用ABAQUS有限元软件进行数值建模,分别考察在大偏压和小偏压作用下试件的破坏模式和破坏机理,并通过参数分析,研究混凝土强度、钢材强度、加载角和肢厚比等参数对试件力学性能的影响规律。研究结果显示:在大偏压和小偏压破坏时,主钢件均非全截面屈服,而是在中性轴附近存在弹性核;在小偏心受压时,提高混凝土强度等级可明显增加试件的极限承载力,而在大偏心受压时 ...
李媛萍, 林启颖, 李国飞
doaj   +2 more sources

电涌保护器中压敏电阻并联的方法和理论分析

open access: yesDianci bileiqi, 2004
为了提高电涌保护器中压敏电阻的耐电流冲击性能,可采用压敏电阻的并联组合。通过对并联组合后的压敏电阻电性能的分析,认为电流偏差是由于限制电压不相等(Ua1≠Ua2)和动态电阻不相等(Rz1≠Rz2)两个因素造成的,且动态电阻越大,电流偏差越小。压敏电阻并联时,可取限制电压Ua相等,而动态电阻Rz相差不超过规定值;也可取动态电阻Rz相等,限制电压Ua相差不超过规定值,使电流偏差在10%范围内。
王茂华, 胡克鳌, 张南法
doaj  

ZnO压敏陶瓷势垒高度的测量及其应用

open access: yesDianci bileiqi, 2010
系统分析了势垒高度测量的两种常用方法(I-T特性方法和C-V特性方法)成立的条件,发现直接采用lnj~1/T曲线的基本I-T特性方法适用于流过ZnO压敏陶瓷的电流较小,导电机制为热发射电流的情况,且只能得到等效势垒高度,其最大误差为12%~20%。要使测量误差在10%以内,则外施电压的荷电率不应超过0.4~0.6。改进后的I-T特性方法可测量零偏置电压下的势垒高度准0;C-V特性方法仅适用于偏析层厚度可忽略的情况,否则测量值明显偏大;实际上将两种方法相结合,不但能得到较精确的势垒高度准0 ...
成鹏飞, 王玉平, 于长丰
doaj  

端板连接普通螺栓群中和轴位置研究

open access: yesJianzhu Gangjiegou Jinzhan, 2023
以螺栓群偏心距和端板厚度为研究参数,对梁柱节点中端板连接在偏心拉力作用下(A组)和纯弯矩作用下(B组)的螺栓群进行了受拉性能试验研究。通过对破坏模式、螺栓群受力分布和中和轴偏移率的分析,研究了端板连接普通螺栓群中和轴位置变化的情况;对两组试验开展有限元分析,从荷载-位移曲线和节点抗拉性能两方面进行研究。结果表明:随着荷载逐渐增大,螺栓群中和轴不断向受压区移动;增大螺栓群偏心距可使螺栓力增大,且加快中和轴向受压区偏移;增加端板厚度能够减小螺栓力,并延缓中和轴向受压区偏移 ...
王安涟   +5 more
doaj  

Home - About - Disclaimer - Privacy