Search

The film–substrate architectures are a promising design for improving tensile ductility of metallic glasses. Recent experiments have shown that cracking of amorphous metallic glass films is the major fracture mode of the film–substrate systems subjected to tensile loading. In this study, calculations are carried out for multiple cracking of an amorphous metallic glass film bonded to a ductile substrate. The pressure sensitive yielding, plastic dilatancy and post-yield strain softening caused by evolution of free-volume of the amorphous film are accounted for; furthermore, the competition between brittle cleavage and shear band induced cracking in the amorphous film is considered in the numerical analyses. It is found that for thin films, the multiple cracking behavior is associated with development of shear bands, and small crack spacing involves interaction of multiple shear bands, which can further activate the mechanism of substrate confinement and leads to large critical strain for film cracking. The multiple cracking in thick amorphous films is governed by brittle cleavage mechanism, which suppresses plastic deformation in the film and gives rise to small critical strain for film cracking. For the amorphous film with intermediate thickness, the shear band induced cracking dominates in the case of small crack spacing, while brittle cleavage mechanism is responsible for the multiple cracking of amorphous films with large crack spacing. The findings of this study shed new lights on the design of reliable film–substrate systems. [ABSTRACT FROM AUTHOR]

The social network perspective provides a valuable lens to understand the effectiveness of team leaders. In understanding leadership impact in team networks, an important question concerns the structural influence of leader centrality in advice-giving networks on team performance. Taking the inconsistent evidence for the positive relationship of network centrality and leadership effectiveness as a starting point, we suggest that the positive impact of leader centrality in advice-giving networks is contingent on team needs for leadership to meet communication and coordination challenges, which we argue are larger in larger teams. Developing our analysis, we examine the mediating role of member collaboration in the relationship of leader network centrality and team performance as moderated by team size. Based on a multi-source dataset of 542 employees and 71 team leaders, we found that leader centrality in advice-giving networks related positively to team performance in larger teams but negatively in smaller teams. Results supported the mediated moderation model via member collaboration in smaller teams, but not in larger teams. [ABSTRACT FROM AUTHOR]

Researchers have emphasized the value of authenticity, but not much is known about what makes a person authentic in the eyes of others. Our research takes an interpersonal perspective to examine the determinants of followers' perceptions of leader authenticity. Building on social identity theory, we propose that two fundamental self-identifications–a leader's sense of uniqueness and sense of belongingness–interact to influence followers' perceptions of a leader's authenticity via perceptions of a leader's self-concept consistency. In a field study conducted among leader–follower dyads and in a controlled laboratory experiment, we find that when a leader feels a low sense of belongingness, there is a positive relationship between a leader's sense of uniqueness and perceptions of leader authenticity. When a leader feels a low sense of uniqueness, there is a positive relationship between a leader's sense of belongingness and perceptions of leader authenticity. This is because followers perceive this leader as having high self-concept consistency. [ABSTRACT FROM AUTHOR]

Near-field coupling effect in the narrow gaps between two metallic probes strongly enhances the electromagnetic field. In this paper, we design and implement a concurrent scanning double-tip-enhanced Raman scattering (CS-TERS) system, which can strongly enhance the tip-enhanced Raman scattering (TERS) enhancement factor without the restriction on the sample height. We use finite-difference time domain (FDTD) simulations to study the enhancement properties of double-tip-enhanced Raman scattering and then discuss the tip taper angle dependence of the TERS enhancement. The obtained results show that the proposed CS-TERS system can be implemented without the near-field coupling effect between the metal tip and the metal substrate; thus, the height of the measured sample will be greatly enlarged and the application of TERS method will be expanded. [ABSTRACT FROM AUTHOR]