Dynamic balance between grain refinement and grain growth during high-pressure torsion of Cu powders

High-pressure torsion (HPT) was applied to unmilled coarse-grained (CG) Cu powders with low initial dislocation density and cryomilled nanocrystalline (nc) Cu powders with high initial dislocation density, with identical processing parameters. HPT of unmilled CG Cu powders resulted in exceptional grain refinement and increase in dislocation density, whereas significant grain growth and decrease in dislocation density occurred during HPT of cryomilled nc Cu powders. Equilibrium structures were achieved under both conditions, with very similar stable grain sizes and dislocation densities, suggesting dynamic balances between deformation-induced grain refinement and grain growth, and between deformation-induced dislocation accumulation and dislocation annihilation. The equilibrium structures are governed by these two dynamic balances.     

Stress-enhanced grain growth in a nanostructured aluminium alloy during spark plasma sintering

In this study, we report on the influence of high pressure on the microstructure evolution of cryomilled nanostructured Al alloy powders during spark plasma sintering (SPS). Our experimental results suggest that the particular mechanism that governs grain growth during SPS depends on the magnitude of the applied pressure. In the case of material consolidated at a high pressure (e.g. 500 MPa), grain coarsening occurs via a combination of thermally activated grain boundary (GB) migration, stress-coupled GB migration and grain rotation-induced grain coalescence. In contrast, in the case of the material consolidated at a low pressure (50 MPa), grain growth occurs primarily via thermally activated GB migration.     

Health psychology in international perspective: A summary and some thoughts for the future

This article reviews the progress made by the field in its short history and attempts to look at developments which seem likely to occur as the field matures.

Recommendations are made for training of health psychologists in the future and a plea is made for international standardisation of health psychology training programmes at the Ph.D. level which incorporate research and clinical training. Health psychologists are further encouraged to take a more active public and political role in order to provide needed visibility for their work.     

The wonderful adventures of Nils: or Taking leave of childhood

The relationship between neuroscience and psychoanalysis is studied by taking “the new mechanism of neuroscience” under scrutiny. That new trend stresses that neuroscientific explanations are mechanistic explanations in particular. Since the issue of psychological mechanisms lies at the core of psychoanalysis, it is crucial to study the relationship between neural and psychological mechanisms. The authors argue that neuroscience cannot verify psychoanalytic theories. However, by combining neuroscientific and psychoanalytic (psychological) viewpoints, it will be possible to approach a more holistic picture of psychological phenomena, here suggested by a new conception of defense mechanisms.     

2型糖尿病患者焦虑抑郁状况及影响因素研究

为探讨2型糖尿病患者焦虑、抑郁状况及影响因素,对243例患者使用SAS、SDS、DSQL量表进行横断面调查。结果显示SAS、SDS评分均高于国内常模;多元回归分析显示有并发症、文化程度低的患者更易出现焦虑情绪,并发症出现时更易出现抑郁情绪。提示糖尿病患者普遍存在焦虑、抑郁等负性情绪,因此对医护人员要进行规范系统的心理干预培训,特别对病程10年、有并发症、文化程度较低的患者更要进行一对一的心理健康教育指导。     

工作记忆负载对特性干扰子激活和抑制加工的影响

在同一实验条件下采用干扰效应和负启动效应双指标考察了三种不同类型工作记忆(WM)负载对特性干扰子加工的影响,旨在求证胡耿丹等人从位置干扰子加工所提出的"双重作用机制"是否适用于特性干扰子加工,以及对Park等人的负载特异机制观点所做的拓展和完善在特性干扰子范畴内是否正确。结果显示:(1)WM负载对特性干扰子的加工亦存在双重作用机制,提示双重作用机制在单一WM负载范围内具有普适性;(2)当目标刺激与干扰子刺激的属性一致时,无论是在位置干扰子还是在特性干扰子视角下Park等人的负载特异机制观点均可一致地被拓展和完善。     

“镜像”的内涵与外延:围绕镜像神经元的争议

镜像神经元被认为是改变认知神经科学的重要发现,它的发现为迄今为止许多行为实验难以检验的心智或认知现象提供了一个统一的研究视角。然而,镜像神经元在社会认知活动中的重要作用却引起了研究者的激烈争论。系统回顾镜像神经元研究中的争议,可以尝试以争论焦点出现的逻辑关系和性质为依据将其划分为两类:一类是关于镜像"内涵"的争议,主要包括镜像神经元是否存在及其起源的争议。另一类则主要围绕镜像"外延"的争议,即有关镜像神经元系统和镜像机制的争议。未来的研究必须摒弃将镜像神经元视为"认知科学圣杯"的神经还原主义倾向,将之视为一个由多个子系统组成的开放的复杂巨系统,并将焦点转向关注镜像机制。     

语义通达对语言标识效应产生的必要作用

大量研究表明语言标识对情绪体验具有调节作用，但并未深入分析这种调节效应产生的内在机制。本研究自下而上操纵标识词的形、音、义信息，探察不同效价情绪的标识效应产生对词汇形、音、义信息的依赖性。结果发现，与仅具有音、形信息的假词相比，真词作为标识词时可以显著降低被试对负性图片的消极体验。表明词汇语义信息的通达是标识效应产生的必要条件，仅具有词汇音和形的信息不足以产生标识效应。     

在社区卫生服务中引入第三方介入机制的探索

社区卫生服务是我国卫生体系的重要组成部分。从目前社区卫生服务中公共卫生服务发展缓慢、监督管理体制不健全等问题入手,通过借鉴国外适宜经验,提出在社区卫生服务中引入第三方机制的设想,以此推动社区卫生服务的可持续发展。     

移植排斥反应中若干问题的思考

随着器官移植术和免疫抑制药物的发展,器官移植已成为挽救各类终末期器官功能衰竭患者的最有效手段。然而,移植排斥反应依然是困扰移植学界的难题。移植排斥反应的发生机制和治疗过程中体现了矛盾的普遍性和特殊性,用辩证思考的方法可以有效地指导移植排斥反应机制研究和临床治疗。