Thermal stability of nanocrystalline fcc and hcp Ni(Si) synthesized by mechanical alloying of Ni90Si10

The thermal stability of nanocrystalline fcc and hcp Ni(Si), obtained by mechanical alloying of Ni₉₀Si₁₀, has been studied. The allotropic transformation from fcc to hcp Ni(Si) is accompanied by a volume expansion of 8.6% and is observed when fcc Ni(Si) reaches a critical crystallite size of 10nm. The hcp phase transforms to stable fcc Ni(Si) at 573K. It has been identified that the lattice distortion in nanometre-sized crystallites from the equilibrium configuration and the decrease in the interfacial energy with grain refinement act as self obstacles in controlling the grain growth of nanocrystalline materials.     

Temperature dependence of the plastic flow behavior of tantalum

Nanoindention has been used to study the plastic flow behavior of bcc Ta(001) in the temperature range 25–200°C. Most notably, it is found that the shape of the load–displacement curves changes with increasing temperature. Only one large discontinuity marking the onset of plasticity is observed in room-temperature experiments, whereas multiple pop-ins separated by elastic reloading segments were observed at 200°C. Detailed analysis of the load–displacement curves indicates that the lattice resistance decreases with increasing temperature, consistent with the mobilization of screw dislocations by thermal activation. Contributions from the oxide layer and/or thermal drift can be excluded.     

On the plasticity event in metallic glass

Based on a systematic molecular dynamics analysis, this study reveals that plastic deformation of metallic glass is not through a uniform configuration change but via many localized plasticity events. These events are manifested by the atomic clusters of high kinetic energy and high strain rate, emerging even in the elastic deformation regime. The life of such a plasticity event is on the order of 10^?12?s, during which the distribution of kinetic energy follows a power law. The study shows that yielding in metallic glass occurs at the sudden surge point of the number of plasticity events. In the steady plastic deformation regime, the continuous nucleation and annihilation of the plastic events lead to a steady flow stress and stabilized total potential energy.     

脂肪源性干细胞（ADSCs）在美容整形外科应用的基本概念

近来,干细胞作为一种利用最大自疗能力的治疗方法在医学领域得到了迅速发展。很多文献报道,利用脂肪源性干细胞（ADSCs）进行自体脂肪细胞移植在提高脂肪移植的成活率和持续性方面,取得了良好的效果,并越来越受欢迎。目前,干细胞的功能尚没有完全阐明,后续关于干细胞的研究使其内容随时发生变化的可能性是存在的。但是干细胞和 ADSCs 的基本概念需要每一位整形美容外科医生掌握。本文将主要介绍当前干细胞和脂肪源性干细胞的一些基本概念。     

自体脂肪移植的临床应用

脂肪移植手术便于操作、创伤小、恢复快、效果好,备受整形外科医师青睐。随着技术的进步,自体脂肪移植应用范围不断扩展,其应用于整形美容外科的各个方面,用于修复各种原因造成的软组织缺损。脂肪移植手术过程包括脂肪的获取、脂肪的处理以及脂肪移植,已经是一项成熟的技术。但是,脂肪移植手术仍有很多的未知区域,比如脂肪成活机制,影响脂肪成活率的因素等,现对脂肪移植的应用作一综述。     

应用烧伤整形外科技术治疗大面积皮肤撕脱伤

探讨大面积皮肤撕脱伤的治疗方法。分析总结大面积皮肤撕脱伤及合并损伤17例,根据伤情综合应用清创撕脱皮肤缝合、带蒂真皮下血管网皮瓣回植、撕脱皮肤反取皮回植、组织瓣转移修复、游离皮片移植、头皮取皮术、异体／异种皮移植、创面持续负压吸引VSD等治疗方法,观察创面修复、肢体外观及功能恢复情况。结果17例患者经综合治疗后创面均愈合。功能部位均予全层皮片或皮瓣修复;19处创面有深部组织外露,予皮瓣或肌瓣修复;随访6个月～3年,所有肢体功能良好。根据皮肤软组织损伤情况而综合运用多种烧伤整形外科技术修复大面积撕脱伤可缩短疗程,并最大可能保留受伤区域的功能与外观,改善患者生活质量。     

Attentional factors in conceptual congruency

Conceptual congruency effects are biases induced by an irrelevant conceptual dimension of a task (e.g., location in vertical space) on the processing of another, relevant dimension (e.g., judging words' emotional evaluation). Such effects are a central empirical pillar for recent views about how the mind/brain represents concepts. In the present paper, we show how attentional cueing (both exogenous and endogenous) to each conceptual dimension succeeds in modifying both the manifestation and the symmetry of the effect. The theoretical implications of this finding are discussed.     

Eternity’s Death in Modernity: A Case of Murder? Of Resurrection?

ABSTRACT

The death of God and the death of eternity stand at the portals of modernity. Hegel’s Phenomenology of Spirit, which Kojève called the modern counterpart to the Bible, concludes with the death of God. Despite Hegel having shown that everything, even God, has a time nucleus, at the level of ‘Absolute Knowing’, he takes eternity back into play, conceiving it as a structure of time, rather than a realm outside time. Thus, he wrenches a concept of eternity from time itself. Even though Hegel and Nietzsche are philosophical antipodes in many senses, we notice an ambivalent relation in Nietzsche’s works towards eternity as well. Nietzsche, the author of Thus Spoke Zarathustra, the other ‘anti-Bible’ of modernity, proclaims eternity to be dead, while at the same time conceiving of an eternal recurrence, that of a dynamic eternity. First, it is argued that for both, eternity is essentially related to action and deed. Second, both highlight the importance of the past in reaching an adequate understanding of time and with it of eternity. Consequently, it is argued that modernity does not offer a vision of the future but a vibrant and often painful consciousness of the past.