Results 71 to 80 of about 16,885 (222)
Melting Preparation for Tungsten‐Doped Graphene/Copper Composites
Rare Metals, Volume 45, Issue 3, March 2026.ABSTRACT Melting production plays a pivotal role in the modern copper industry. However, applying this process to fabricate nanocarbon (e.g., graphene, carbon nanotubes)‐reinforced copper matrix composites has remained a long‐standing challenge for nearly 2 decades.
Yunzhong Wu +9 more
wiley +1 more source
Gaoya dianqi, 2017 文中搭建了真空断路器试验平台,实现了主轴卡涩等四类机械故障状态。通过将正常及故障状态下的实测振动信号进行经验模态分解,得到所需要的内禀模态函数（intrinsic made function,IMF）,利用能量法求出包含主要故障特征信息的各内禀模态函数分量的能量总量。利用IMF分量能量总量作为特征向量,并以此作为支持向量机输入,分析对比了不同分类策略、核函数的分类时间和分类准确率,经实验分析选用"一对其他"分类策略并且核函数为径向基函数的分类效果最优 ...
冯英 +5 more
doaj
Research on residual stress measurement and vibration stress relief of sheet metal [PDF]
, 2017 小孔法的塑性效应会给高残余应力测量带来误差，为了解决这个问题，论文中对ASTME837-13a标准中的校准系数的塑性修正进行了研究。同时，组建了用于金属薄板件振动时效的电磁激振系统，研究了振动时效消除金属薄板件的残余应力。论文的研究内容围绕以下几个方面展开。 首先，研究了小孔法测量铝合金构件高残余应力的塑性效应修正方法。基于形状改变比能密度理论，对ASTME837-13a标准中的校准系数进行塑性修正；结合双线性弹塑性理论，采用ANSYS软件进行有限元仿真标定；使用电子万能试验机进行拉伸加载实验验证 ...
林俊辉
core
, 2019 对PCB在运输与使用过程中受振动影响易产生故障的问题,提出一种新型的电路板动力学与电路联合设计方法,能在满足电路设计的前提下,提高它的抗振特性。基于PCB的动力学分析,确定电路板的模...国家自然科学基金(51875490);; 航空科学基金(20171668003);; 航空动力基金(6141B090562);; 厦门市科技计划项目(3202Z20173021);; 中央高校基本科研业务费专项资金 ...
余少炜 +3 more
core +1 more source
Functional Ecology, Volume 40, Issue 3, Page 750-763, March 2026.Read the free Plain Language Summary for this article on the Journal blog. Abstract Forests worldwide are increasingly impacted by drought due to climate change, prompting plants to adapt through dehydration tolerance (DT) and avoidance (DA), two distinct physiological strategies.
Xingyun Liang +11 more
wiley +1 more source
Gaoya dianqi, 2018 随着电力系统发展,纯机电暂态和电磁暂态仿真在分析大规模特高压交直流混合电网时已呈现明显不足。为了准确分析特高压交直流输电系统的动态特性,文中基于电力系统全数字实时仿真平台（ADPSS）搭建了特高压交直流输电系统的机电—电磁暂态混合仿真模型,并对整流侧和逆变侧交流母线故障进行了仿真分析。结果表明通过机电—电磁暂态混合模型仿真结果输出,能够有效体现直流系统整体以及局部的各个元器件的详细动态过程,为特高压交直流系统的稳定控制提供技术理论支撑。
王亮 +5 more
doaj
Surface texture analysis for ultra-precision flycutting machining based on the dynamic characteristics of machine tools [PDF]
, 2016 采用超精密飞切加工技术可获得软脆性平面光学元件的最终表面,而元件表面微观形貌的加工可控性对于光学元件使用性能有直接影响。首先运用多尺度小波分解方法,对飞切机床的加工表面波纹进行了特征提取,得到了工件表面波纹的频率组成及占比;然后通过对机床主轴系统的有限元分析,结合冲击振动测试,找到了与工件表面波纹对应的模态;最后通过对机床的在线振动测试及加工实验进一步明确了飞切加工表面微波纹的成因。结果表明:表面波纹在17 mm左右的空间周期上存在最大的分量,显著影响光学元件的精度和使用效果 ...
孙郅佶 +5 more
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Policymaking for Emigrants in Latin America and the Caribbean: A Mixed‐Methods Study
Latin American Policy, Volume 17, Issue 1, March 2026.ABSTRACT While scholars have identified models of political emigrant policies across countries, we still lack an understanding of how these models come about and persist. Using a sequential mixed‐methods approach—including quantitative analysis of policy mixes in 22 Latin American and Caribbean countries and a comparative case study of Colombia and ...
Luicy Pedroza, Pau Palop‐García
wiley +1 more source
Force-measuring System Optimization and Simulation Analysis Of Wire-driven Parallel Suspension System [PDF]
, 2015 摘要 绳牵引并联机构作为一种新型的低速风洞模型支撑系统，因具有速度快、结构简单、承载能力大以及对流场干扰小等诸多优点而备受关注。同时由于该类系统通常具有冗余驱动的特点，因此绳拉力优化、绳拉力准确测量以及绳索系统建模仿真成为待解决的关键技术。本文主要从这三个方面展开研究，主要工作及成果如下所述。 首先，建立了WDPSS-8的运动学模型和空间平衡方程。对于WDPSS-8机构因冗余驱动而导致的绳拉力多解问题，本文在运动学模型分析的基础上提出一种基于遗传算法的绳拉力优化求解方案 ...
江子扬
core
NEPA “Modernization”: From the Trump Administration to the Biden Administration
Review of Policy Research, Volume 43, Issue 2, March 2026.ABSTRACT Researchers have recently examined changes to American environmental policy under the Trump administration's first term, and to a lesser extent, under the Biden administration. Scholars have largely not considered changes to the National Environmental Policy Act (NEPA), one of the earliest environmental laws in the United States, and a law ...
Michelle L. Edwards
wiley +1 more source