Results 111 to 120 of about 1,091,898 (247)
The value of herbarium specimens depends largely on the accuracy and accessibility of the data captured, which is dependent on curation practices. Previous studies have shown high levels of misidentification in collections, which become more problematic with increased access.
Celia C. Aceae +3 more
wiley +1 more source
为探索将高精度CFD分析引入高超声速飞行器气动外形优化设计的可行性,以6°飞行攻角、6马赫飞行速度下的最大升阻比为目标,引入CFD分析计算气动性能,使用Nelder-Mead可变多面体搜索方法对高超声速弧形翼导弹进行了气动外形优化.计算结果表明,在满足弹翼安全性的条件下,优化外形比初始外形的升阻比有明显提高(约9.22%),同时阻力系数、弹翼展长和弹翼面积均有不同程度的降低.计算结果充分证明了优化设计的有效性和采用CFD分析的必要性 ...
崔凯, 杨国伟
core
Brazil's diverse flora is under several threats, with many unique lineages facing extinction, particularly in biodiverse regions like the Cerrado and campo rupestre. This study sheds light on the conservation needs of Cambessedesia (Melastomataceae), an endemic genus with 95% of its species endangered, using an approach to rank and prioritise species ...
Najla Bastos Scheidegger +4 more
wiley +1 more source
建立了针对柱形真空杜瓦容器端盖密封结构的轴对称模型.基于有限元软件ANSYS的结构非线性分析模块,分析了内、外密封圈与端盖的接触响应,得到了中心盖板的挠度、密封圈的变形与接触压力.求解了考虑密封圈的变形抗力时,螺栓需提供的压紧力附加值 ...
金乘进, 吴臣武, 曹洋
core
Microstructure Engineering Toward High Cost‐Effective Nd–Fe–B Sintered Magnets: A Review
ABSTRACT Nd–Fe–B sintered magnets, critical for enhancing electromechanical conversion efficiency and operational stability in wind turbines and electric vehicle drives, are prized for their outstanding coercivity, high remanence, and superior maximum energy product.
Dongmin Zhang +5 more
wiley +1 more source
提出了一种基于形态学的非线性小波分析方法,并将这种形态小波分析方法应用于图象编码上.与一般的小波分解方法不同的是,该形态小波分解采用非线性方法,分解结果中图象特征更明显,图象编码压缩比更高,解码出的图象更加清晰;同时由于形态学是基于Minkowski加减基本操作并应用最大最小运算来实现,分解运算简单,速度快.
刘循, 游志胜
doaj
ABSTRACT This study developed a metal–modified fluoroethylene vinyl ether (FEVE) organic coating on 6061 aluminum alloy, supported by a micro‐arc oxidation (MAO) pretreatment layer, to enhance corrosion resistance and antifouling performance in marine environments.
Chang Liu +5 more
wiley +1 more source
作者采用了有限元素法,就500千伏SF6绝缘设备的锥形及盘形绝缘子的电场分布进行了计算和分析,弄清了绝缘子的形状,倾角、厚度、屏蔽体的形状等因素对电场分布的影响,取得了三个较为满意的绝缘子设计方案。
姚抚城, 黎明
doaj
对薄板成形应变场传统的测量方法进行了研究 ,指出了其不足和误差的来源 ,提出了数字图像分析法测量薄板成形中的应变场 ,对测量原理、新的测量方法对传统方法的改进 ,以及如何降低误差进行了介绍 ,指出数字图像分析法的前景 ...
王勇, 陈光南, 罗耕星
core
ABSTRACT The construction of core–shell grains can enhance the coercivity of Nd2Fe14B magnets. However, it is a significant challenge to elucidate the formation of these core–shell grains particularly regarding the spontaneous core–shell structure in Y‐substituted Nd2Fe14B alloys.
Sining Fan +13 more
wiley +1 more source

