Results 121 to 130 of about 31,003 (237)
Performance enhancing and plastic deformation mechanism of nanocrystalline transition metal nitride hard coatings [PDF]
, 2016 针对高速干式切屑加工的苛刻服役环境，本文研究工作主要集中于优化提升Zr基及Cr基氮化物硬质涂层的力学及抗氧化性能；探讨氮化物硬质涂层的塑性变形机制；并建立硬质涂层组织结构与性能演变之间的关联。本文从涂层成分设计及结构设计角度出发，阐述了优化提升Zr基及Cr基氮化物硬质涂层力学及抗氧化性能的方法；同时也提出研究二维薄膜材料塑性变形行为的实验方法，并归纳出硬质涂层塑性变形机制的研究内容。本文所取得的主要结论如下： （1）、掺杂元素的离子半径决定了涂层晶胞参数的变化规律 ...
吴正涛
core
Humour as a Pedagogical Tool: Evidence and Implications for Critical Geography
Antipode, Volume 57, Issue 4, Page 1493-1514, July 2025.Abstract In this article, we elaborate the results of a focused empirical study on the use of humour in teaching undergraduate geography courses. Through semi‐structured interviews and weekly reflections submitted by students, we delve into a diverse array of experiences and perceptions of humour as a pedagogical tool.
Ben A. Gerlofs, Xuechao Zheng
wiley +1 more source
Investigation on Martensitic Transformation and Shape Memory Effect at High Temperature in Co-V-X (X: Si, Al) Alloys [PDF]
, 2017 形状记忆合金是一种具有形状记忆效应和超弹性的智能材料，用作驱动元件时，具有响应频率高、可回复应变大等优点。但是在传统的形状记忆合金中，马氏体相变温度较低，难以达到一些高温环境下特殊应用的要求。由此，研究者们开发出了一些具有较高马氏体相变温度的形状记忆合金，即高温形状记忆合金。然而，在已有的高温形状记忆合金中，各自存在着一些主要的问题：一是在较高的温度下，马氏体的热稳定性较差；二是在多晶合金中，由金属间化合物转变而来的马氏体脆性较大，影响到高温形状记忆合金的延展性 ...
蒋恒星
core
New Phytologist, Volume 247, Issue 2, Page 504-517, July 2025.Summary Repetitive DNA is a feature of all organisms, ranging from archaea and plants to humans. DNA repeats can be seen both in coding and in noncoding regions of the genome. Due to the recurring nature of the sequences, simple DNA repeats tend to be more prone to errors during replication and repair, resulting in variability in their unit length ...
Sridevi Sureshkumar +3 more
wiley +1 more source
Effect of Residual Thermal Stresses on Fracture Behavior and Mechanical Properties of Al sub 2 O sub 3/Ni Cermets [PDF]
, 2002 Effect of residual thermal stresses on fracture behavior and mechanical properties of Al2O3/Ni cermets was qualitatively explained by using theory on residual thermal stresses. When Ni particles are located within Al2O3 grains or Ni content is relatively
Chen, Da Ming +3 more
core +1 more source
New Phytologist, Volume 247, Issue 1, Page 144-159, July 2025.Summary Domesticated chickpea cultivars exhibit limited genetic diversity. This study evaluated the effects of chickpea domestication on phosphorus (P)‐use efficiency (PUE) under low‐P conditions, using a diverse Cicer collection, including wild species. Two wild Cicer species – 54 C. reticulatum accessions and 15 C. echinospermum accessions, and seven
Jiayin Pang +8 more
wiley +1 more source
Research of Preparation and Modification of Bio-based Waterborne Polyurethane [PDF]
, 2017 聚氨酯（PolyurethanePU）一般是指在高分子链的主链上含有重复的氨基甲酸酯键结构单元的高分子化合物。传统聚氨酯一般以有机溶剂作为分散剂，但是随着人们环保意识的增强，聚氨酯的发展正在逐渐向着无溶剂的方向发展，以水为分散介质的水性聚氨酯（WaterbornepolyurethaneWPU）成为研究的热点。 生物质资源作为一种可再生能源，充分利用这一能源对现代社会有很重要的意义。本研究创新地将生物质液化液作为反应原料，成功制备生物基水性聚氨酯。研究中主要选用笋壳作为液化原料，以质量比为1 ...
王帅
core
Jianzhu Gangjiegou Jinzhan, 2017 工字形加劲肋带缝钢板剪力墙具有延性好、耗能能力强等优点,可有效避免钢板剪力墙对框架柱产生附加荷载而导致相邻框架柱过早发生破坏。对带缝钢板剪力墙以及工字形加劲肋带缝钢板剪力墙的弹性屈曲特征、滞回性能、应力、应变分布规律等力学性能进行了对比分析。结果表明,工字形加劲肋带缝钢板剪力墙的屈曲临界荷载为无加劲肋带缝钢板剪力墙屈曲临界荷载的2.15倍;工字形带缝钢板剪力墙的滞回曲线稳定且饱满,强化阶段被充分发挥,其抗侧承载力、延性及耗能能力显著提高 ...
阮明创, 徐颖
doaj