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121.
The microhardness and microstructural characteristics and subsequent heat treatment of conventionally solidified Al64Cu20Fe12Si4 quasicrystal were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS), differential thermal analysis (DTA), and Vickers microhardness tester. XRD analysis indicated that the conventionally solidified samples showed a quasicrystalline icosahedral phase (i-phase) together with cubic β-AlFe, tetragonal θ-Al2Cu, and monoclinic λ-A13Fe4 crystal phases. However, the i-phase together with cubic β-AlFe and monoclinic λ-A13Fe4 phases observed heat threaded samples. As-cast and subsequently heat-treated quasicrystal samples were measured using a microhardness test device. Vickers microindentation tests were carried out on the heat-treated quasicrystal samples with the load ranging from 1 to 500?mN at room temperature. The melting point of the i-phase was determined as 900°C by DTA examinations. 相似文献
122.
Coline Beal Xavier Kleber Damien Fabregue Mohamed Bouzekri 《Philosophical Magazine Letters》2013,93(4):297-303
The cracking resistance of a twinning induced plasticity (TWIP) steel with high-manganese content has been studied in relation to the liquid metal embrittlement phenomenon. This phenomenon was investigated by hot tensile tests carried out on electrogalvanised specimens using a Gleeble® simulator at temperatures ranging from 600°C to 1000°C. The results show that this steel can be embrittled by liquid zinc within a limited range of temperature depending on strain rate. 相似文献
123.
P. Grassia 《Philosophical Magazine Letters》2013,93(6):403-409
A model of the structure of two-dimensional foam (cells separated by circular arcs (films) meeting at threefold vertices) is considered. Films that are so curved as to be nearly semicircular arcs are problematic for conventional foam structure computations, which aim to identify the pressures needed to achieve specified bubble areas. When the films have near semicircularity, tiny variations in pressure can lead to large changes in the computed bubble area, and hence a failure to meet the specified targets. A new algorithm for determining foam structure is presented. It is based on 'freezing' most of the system, except the nearly semicircular arcs, and then finding the particular bubble pressures associated with the latter via an analytic approximation. This procedure is shown to work well for structure relaxation in a small bubble cluster. Large relaxed bubble clusters are considered briefly at the end of the paper. 相似文献
124.
J. Saida M. Imafuku S. Sato T. Sanada E. Matsubara A. Inoue 《Philosophical Magazine Letters》2013,93(3):135-144
The local structure of Zr70Al9Ni20Pd1 metallic glass, in which a nano-icosahedral quasi-crystalline phase (I-phase) is formed in the primary stage of crystallization, has been examined and compared with that of Zr70Al10Ni20, the supercooled liquid state of which has a high stability. Since the local environments around the Zr and Ni atoms do not change drastically by the addition of 1 at.% Pd to Zr70Al10Ni20, as evidenced by radial distribution function (RDF) and extended x-ray absorption fine structure (EXAFS) studies, we deduce that the icosahedral phase formed in the Zr70Al9Ni20Pd1 metallic glass has a local structure similar to that in Zr70Al10Ni20. Although a very slight rearrangement of Zr–Zr atomic pairs occurs during quasi-crystallization, the I-phase formation is achieved without disturbing the dominant local structure in the glassy state of the Zr70Al9Ni20Pd1. An icosahedral local structure is proposed for Zr–Al–Ni metallic glass system as well as for primary quasi-crystal (QC)-forming Zr-based metallic glasses. 相似文献
125.
New developments in flexible electronics require metal films to adhere to polymer substrates. Measuring the interfacial adhesion of these systems is challenging, requiring the formulation of new techniques and models. A strategy to measure the adhesion of Cr–polyethylene terephthalate (PET) interfaces using tensile straining and buckle formation is presented in this article. Focused ion beam cross-sectioning of the buckles reveals that the polymer substrate can locally fail, which may lead to an overestimate of adhesion. Cr–PET adhesion energy of 9.4?±?1.6?J/m2 is determined with the present approach. 相似文献
126.
Dmitry Orlov Matthias Hockauf Lothar W. Meyer Yuri Estrin 《Philosophical Magazine Letters》2013,93(9):541-549
The effect of ultrafine-grained structure formation in Mg–Zn–Zr alloy ZK60 on its mechanical response was investigated at strain rates ranging from quasi-static to dynamic regimes. The study demonstrated that the strength characteristics of the material rise significantly with increasing strain rate, while its ductility is reduced. These effects are particularly pronounced in the dynamic loading regime, at strain rates in the (1?5)?×?102?s?1 range. In the ultrafine-grained alloy ZK60, the energy absorption per unit volume, W, is enhanced by grain refinement by a factor as high as eight for the highest strain rate of 5?×?102?s?1 investigated. The analysis is focused on the microstructure features that bring about the observed improvement of the tensile characteristics, as well as the deformation and fracture modes prevalent at different strain rates. The results obtained contribute to the exploration and understanding of dynamic behaviour of magnesium alloys. 相似文献
127.
CHRISTIAN DE QUINCEY 《World Futures: Journal of General Evolution》2013,69(1-2):47-55
There is underway a worldwide shift in society from an industrial‐based to an information‐based metaindustrial way of living and working. This will require innovative organization and management. Three factors are described as propellers of this industrial transformation: technological innovations, technology transfer, and global marketplace. Trends in post‐industrial organizations are mapped out, and a profile of metaindustrial organization culture is created.? 相似文献
128.
Kristin J. Homan 《Mental health, religion & culture》2013,16(10):977-989
Attachment theory posits that insecure attachment is a risk factor for the development of anxiety and depression and ample evidence supports this idea. Research has also demonstrated links between attachment to God and mental health, but little is known about the emotion regulatory mechanism that underlies this relationship. The present study explored the explanatory role of self-compassion in the relation between attachment to God and anxiety, depression, and life satisfaction in a sample of 181 adults who completed an online survey. Elevated attachment anxiety and avoidance were associated with higher depression and anxiety, and lower life satisfaction. Self-compassion mediated these associations (in an inverse direction for anxiety and depression), suggesting that people who feel uncomfortable depending on God, or who fear God's rejection, have difficulty extending kindness to themselves. Possible interventions are discussed in the context of these results. 相似文献
129.
镇静治疗是ICU综合治疗的重要组成部分。随着ICU的发展,先后颁布了3个有关ICU患者的镇静指南,镇静治疗的理念也逐渐发生改变。2013年美国重症医学会颁布的ICU成人患者疼痛、躁动、谵妄治疗指南推荐的镇静目标为浅镇静。该指南是以大量临床研究结论为基础提出的,更具有广泛代表性和推广价值。本文从浅镇静的理论基础、具体实施方案、镇静深度的监测、镇静药物的选择以及浅镇静的局限性等方面具体阐述ICU患者浅镇静策略的相关问题,以期ICU同道能更好地理解和临床实施ICU成人患者的浅镇静策略。 相似文献
130.
We studied the relationship of reciprocity, gender, and racial composition (Caucasian, African American, cross-race) of adolescent friendship dyads to similarity and proximity in 136 young adolescents. We found that adolescents selected friends who were of the same gender and race and that female dyads were more similar than male dyads on verbal achievement and several personality dimensions. Caucasian dyads were more similar than African American dyads on verbal achievement, mental alertness, and dominance. African American adolescents had more contact with their best friends outside school, whereas Caucasian adolescent friends had more in-school contact. African American students had fewer reciprocal relationships than the Caucasian students. Cross-race friendships were less reciprocal than same-race friendships. Race and gender were important in determining friendship patterns. Similarity and proximity were more important than reciprocity in understanding early adolescent friendships. 相似文献