The deformation-induced zone below large and shallow nanoindentations: A comparative study using EBSD and TEM

A comparison is made between the deformation-induced zone beneath nanoindentations obtained by Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM). Since there are resolutional limitations associated with EBSD, especially at very small scan sizes, it is not known how accurately the deformed volume beneath the imprints can be characterized. To aid in answering this question, cross-sectional EBSD and TEM samples of nanoindentations were fabricated by means of a Focused Ion Beam (FIB) workstation, analyzed, and subsequently compared with each other. For large indentations as well as for shallow ones, agreement of the determined zones was found. The results of the EBSD and TEM experiments were also used to characterize the deformed volumes. In the EBSD maps of large indentations, strongly confined deformation patterns were found, while for the shallow indentations the observed patterns are more diffuse. The TEM micrographs and the Selected-Area Electron Diffraction (SAED) support these facts and give insight into the dislocation structure of the deformation zone.     

Post-irradiation annealing behaviour of oxide dispersion strengthened Fe-Cr alloys studied by nanoindentation

ABSTRACT

To study the nature of irradiation-induced nanofeatures in oxide dispersion strengthened (ODS) Fe-Cr alloys, post-irradiation isochronal thermal annealing up to 600°C was performed for ODS Fe-9%Cr and Fe-14%Cr alloys ion-irradiated at 300°C and 500°C. Nanoindentation indicated hardening for all as-irradiated alloys and complete hardness recovery upon post-irradiation annealing. Cross-sectional TEM indicated an irradiation-induced defect band near peak damage mainly consisting of dislocation loops. Candidate mechanisms of recovery were critically evaluated. Shrinkage of loops via capture of thermal vacancies was found to correctly reflect the annealing behaviour of ODS Fe-9Cr irradiated at 300°C.     

A curious metaphor. Engaging with trauma: an analytical perspective

Abstract :  This paper explores the metaphor of in vitro fertilization in respect to those parts of the individual 'frozen' through early trauma. It describes the conditions necessary for the reintroduction of the frozen 'embryo' in the therapeutic relationship through use of an extended example. The role of the analytic relationship and the analyst's countertransference are highlighted within the context of implications for the process of therapy.     

Importance of crack-propagation-induced ε-martensite in strain-controlled low-cycle fatigue of high-Mn austenitic steel

We investigated the roles of deformation-induced ε-martensitic transformation on strain-controlled low-cycle fatigue (LCF) through crack-propagation analysis involving a notching technique that used a focused ion beam (FIB) setup on Fe–30Mn–4Si–2Al austenitic steel. Using the FIB notch, we separated the microstructure evolution into macroscopic cyclic deformation-induced and crack-propagation-induced microstructures. Following this, we clarified the fatigue crack-propagation-induced ε-martensitic transformation to decelerate crack propagation at a total strain range of 2%, obtaining an extraordinary LCF life of 1.1 × 10⁴ cycles.     

Mantle region accommodating two-dimensional grain boundary sliding in ODS ferritic steel

Two-dimensional grain-boundary sliding (GBS) was achieved microscopically in an oxide-dispersion-strengthened ferritic steel with an elongated and aligned grain structure, which was deformed perpendicular to the long axis. At the border between superplastic regions II and III, microscopic deformation was observed using sub-micron grids drawn on the material surface using a focused ion beam. GBS was accommodated by intragranular deformations in narrow areas around grain boundaries, which has been predicted by earlier researchers as characteristics of the core–mantle model. These observations suggest that dislocations slip only in the mantle regions around wavy boundaries to relax the stress concentration caused by GBS during superplasticity.     

氯吡格雷在冠状动脉支架植入术前术后的应用

冠状动脉支架植入术是冠心病治疗的最有效手段之一,但术后支架内血栓形成及再狭窄等影响了其远期疗效。血小板激活是支架植入术后血栓形成过程中最关键的环节。氯吡格雷作为有效的抗血小板药物之一,近年来多个大规模临床试验已经逐渐确立了其在支架植入术前术后应用的地位,但其应用的量、时机、持续时间等问题尚存在争议。     

应紧急叫停活体捐献器官

“不伤害原则”是医学的基本要求。活体摘取器官,则意味着要对另一人造成重大伤害,不如顺其自然。死刑犯其人身自由受到严格限制,又是处在一个相对封闭的环境(监狱)之中,因此,虽有死刑犯生前关于“自愿捐献器官”的书面签字,也难以证明其是真正出于自愿。故器官移植应禁止以死刑犯作为供体来源。     

The ethics of assessing health technologies

Health technology assessment (HTA) consists of thesystematic study of the consequences of theintroduction or continued use of the technology in aparticular context, with the explicit objective toarrive at a judgment of the value or merit of thetechnology. Ideally, it is aimed at assessing allaspects of a given technology or group oftechnologies, including non-technical, e.g.socio-ethical, aspects. However, methods for assessingsocio-ethical implications of health technology arerelatively undeveloped and few mechanisms exist totake action based on the results of such evaluations.Still, the examples of cochlear inplants (CI) and other cases illustratethat HTA is not a matter of merely collecting thefacts about a technology. The facts must beplausible and relevant from a particular framework,which is not always shared by different groups. It ishere that socio-ethical aspects are encountered. Ifhealth technology assessment aims to enhance theaccountability of the decision making processregarding funding and use of health technology, it isa major challenge to assessors of health technologiesto deal adequately with existing value pluralism. Inthis respect interactive evaluation may have somethingto offer.     

从现代系统科学角度看冠状动脉支架置入术后再狭窄

随着介入治疗技术在临床的广泛应用,目前已成为治疗冠心病（CAD）的主要方法之一。目前国内外指南一致推荐对于CAD的大多数de novo病变常规置入支架,可有效减少单纯球囊扩张的并发症和再狭窄的发生率,但支架内再狭窄的形成又日益突出,成为严重影响介入治疗远期疗效的主要问题。对再狭窄发生机制的研究近十年来取得诸多新进展,对其发生机制的研究和探索为解决这个世纪难题提供了理论基础和依据。本文应用现代系统科学的自组织理论,从哲学角度深入认识和理解这一病理过程。     

听觉植入技术的进展与临床应用

听觉植入技术是随着现代科学技术的进展而发展起来的新技术,其成功应用得益于现代科技的进步,更离不开科学家的创新思维和勇于探索精神。听觉植入技术的进展体现了多学科联合发展的要求及创新思维的重要性,其应用前景也是无限光明的。