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231.
In this work, we investigate the susceptibility of Ni–Ti superelastic wires to the strain rates during tensile testing after hydrogen charging. Cathodic hydrogen charging is performed at a current density of 10?A/m² during 2–12?h in 0.9% NaCl solution and aged for 24?h at room temperature. Specimens underwent one cycle of loading-unloading reaching a stress value of 700 MPa. During loading, strain rates from 10?6 to 5?×?10?2??s?1 have been achieved. After 8?h of hydrogen charging, an embrittlement has been detected in the tensile strain rate range of 10?6 to 10?4?s?1. In contrast, no embrittlement has been detected for strain rates of 10?3?s?1 and higher. However, after 12?h of hydrogen charging and 24?h of annealing at room temperature, the embrittlement occurs in the beginning of the austenite-martensite transformation for all the studied strain rate values. These results show that for a range of critical amounts of diffused hydrogen, the embrittlement of the Ni–Ti superelastic alloy strongly depends on the strain rate during the tensile test. Moreover, it has been shown that this embrittlement occurs for low values of strain rates rather than the higher ones. This behaviour is attributed to the interaction between the diffused hydrogen and growth of the martensitic domain. 相似文献
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233.
Fine-grained copper films on a flexible substrate were cyclically deformed under constant strain range control. It was found that cyclic dislocation plasticity through individual dislocation glide is still dominant at the submicrometer scale, while the ability of irreversible slip of dislocations gradually decreases and the damage was changed from extrusion-induced localization to cracking along grain boundary. Statistical evaluation of the mean spacing between slip bands and/or lines leads to a critical scale (~28 nm) below which dislocation-controlled cyclic strain localization would be shut down. 相似文献
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235.
The behaviour of vacancies during isothermal ageing following quenching of an Al-1.7at.% Mg-1.1at.% Cu alloy has been studied by positron annihilation lifetime spectroscopy. The positron lifetime parameters vary in parallel with the Vickers hardness of the alloy, suggesting simultaneous migration of vacancies and changes in the size and concentration of vacancies containing clusters and dislocation loops. The results also explain the long hardness plateau observed previously in ageing experiments carried out between 100 and 240°C in terms of a continuous growth of Mg-Cu-vacancy clusters during ageing. The vacancy concentration of the clusters increases gradually until the setting in of the cluster Guinier-Preston-Bagaryatsky zone transformation. 相似文献
236.
Tirril Harris 《International Forum of Psychoanalysis》2013,22(3):147-156
John Bowlby's Attachment Theory is being increasingly operationalised in the world of developmental research, but as yet its implications for clinical work are relatively less discussed. This paper addresses the issue of the measurement of attachment patterns and how knowledge of these can inform psychoanalysts’ work with their patients. It looks at the implications of Attachment Theory at all stages of the therapeutic process, but concentrates particularly on how it can help with the crucial phase of building the working alliance. 相似文献
237.
为了探讨临床应用A型肉毒素结合病灶小切口括约肌浅表松解术治疗肛裂的新方法,将Ⅱ期、Ⅲ期肛裂患者80例随机分成试验组和对照组,征求患者和伦理委员会同意后进行研究,对比观察试验组的A型肉毒素内括约肌侧方注射配合病灶小切口括约肌浅表松解术与对照组的传统肛裂切除扩创术加部分内括约肌侧方切断术手术治疗的效果.结果显示,试验组VAS疼痛评分(24h)、排便时间、手术所需时间、创面愈合时间、切口愈合分级及切口愈合后瘢痕面积大小情况均优于对照组.静息向量容积和收缩向量容积两组都有所减低(P<0.05).因此,A型肉毒素内括约肌侧方注射配合病灶小切口括约肌浅表松解术的疗效治疗方法简单,伤口愈合快,有很好的应用价值. 相似文献
238.
Yoav Yigael 《World Futures: Journal of General Evolution》2013,69(2):155-178
In the second (and expanded) version of Origin of the Species, Darwin introduces the term “advanced progressive development” in an attempt to describe the development of the more complex species from the simpler ones. More than 100 years have passed since Darwin tried to qualify and conceptualize the directional question of evolution, and very little progress has been made regarding the subject. The appearance of the species, from the simple to the more complex, is today an empirical fact, one which is no longer dependent upon any theory, including that of Darwin. This work examines the subject of advanced development in evolution by attempting to answer a few basic questions: What parameters may be used to evaluate complexity? Can any rules or order be identified as to the development of the species? Is the mechanism of “natural selection” sufficient to explain the direction or ‘purpose’ of evolution? Can the human race be included within the “rules” of Darwin's evolutionary theory? The purpose of this essay is to develop and represent a new conceptual framework. Through this, it will be possible to offer a principle answer to all four questions. 相似文献
239.
Yukio‐Pegio Gunji 《World Futures: Journal of General Evolution》2013,69(1-4):495-510
A model for a system consisting of elements which detect the measurement apparatus of other elements is proposed. By any apparatus one can observe locally, however it can refer to non‐local property because apparatus itself is indefinite. In taking this aspect into consideration, I formulate expressions for a local interaction referring to non‐local property. This formalization can satisfy the aspect of what is called, internal measurement. This system shows teleological global motion toward criticality which is relevant to the degeneracy of a specific element featuring D ? Hom(Z), E) by which infinite time and space are renormalized. 相似文献
240.
Heather L. Scheuerman 《Deviant behavior》2013,34(11):1349-1371
ABSTRACTGender and race condition perceptions of and responses to injustice associated with strain. Yet, it is unclear how various types of injustice (distributive, procedural, and interactional) affect criminal coping by gender and race – especially among Asians and whites. A vignette of an academic group project that depicted a distributive injustice and manipulated procedural and interactional injustice was randomly assigned to a sample of undergraduates. Analyses reveal that injustice is associated with Asian and white males engaging in different types of deviance. Implications for the relationship that gender and race have in affecting perceptions of and responses to injustice are discussed. 相似文献