Complete gate control of supercurrent in graphene p-n junctions

In a conventional Josephson junction of graphene, the supercurrent is not turned off even at the charge neutrality point, impeding further development of superconducting quantum information devices based on graphene. Here we fabricate bipolar Josephson junctions of graphene, in which a p-n potential barrier is formed in graphene with two closely spaced superconducting contacts, and realize supercurrent ON/OFF states using electrostatic gating only. The bipolar Josephson junctions of graphene also show fully gate-driven macroscopic quantum tunnelling behaviour of Josephson phase particles in a potential well, where the confinement energy is gate tuneable. We suggest that the supercurrent OFF state is mainly caused by a supercurrent dephasing mechanism due to a random pseudomagnetic field generated by ripples in graphene, in sharp contrast to other nanohybrid Josephson junctions. Our study may pave the way for the development of new gate-tuneable superconducting quantum information devices.open114344sciescopu

A novel online food recall checklist for use in an undergraduate student population : a comparison with diet diaries

Peer reviewedPublisher PD

Controlled epitaxial growth modes of ZnO nanostructures using different substrate crystal planes

A combined experimental and theoretical investigation has clarified the nanometre-scale vapour-phase epitaxial growth of ZnO nanostructures on different crystal planes of GaN substrates. Under typical growth conditions, ZnO nanorods grow perpendicular to the GaN(0001) plane, but thin flat films form on GaN(10 (1) over bar1), (10 (1) over bar0) and (1 (1) over bar 20). High-resolution X-ray diffraction data and transmission electron microscopy confirm the heteroepitaxial relationship between the ZnO nanostructures and GaN substrates. These results are consistent with first-principles theoretical calculations, indicating that the ZnO surface morphologies are mainly influenced by highly anisotropic GaN/ZnO interface energies. As a result of the large surface energy gradients, different ZnO nanostructures grow by preferential heteroepitaxial growth on different facets of regular GaN micropattern arrays. High-resolution transmission electron microscopy shows that ZnO nanotubes develop epitaxially on micropyramid tips, presumably as a result of enhanced nucleation and growth about the edges.open113031sciescopu

A falling of the veils: turning points and momentous turning points in leadership and the creation of CSR

This article uses the life stories approach to leadership and leadership development. Using exploratory, qualitative data from a Forbes Global 2000 and FTSE 100 company, we discuss the role of the turning point (TP) as an important antecedent of leadership in corporate social responsibility. We argue that TPs are causally efficacious, linking them to the development of life narratives concerned with an evolving sense of personal identity. Using both a multi-disciplinary perspective and a multi-level focus on CSR leadership, we identify four narrative cases. We propose that they helped to re-define individuals’ sense of self and in some extreme cases completely transformed their self-identity as leaders of CSR. Hence we also distinguish the momentous turning point (MTP) that created a seismic shift in personality, through re-evaluation of the individuals’ personal values. We argue that whilst TPs are developmental experiences that can produce responsible leadership, the MTP changes the individuals’ personal priorities in life to produce responsible leadership that perhaps did not exist previously. Thus we appropriate Maslow’s (1976, p. 77) metaphorical phrase ‘A falling of the veils’ from his discussion of peak and desolation experiences that produce personal growth. Using a multi-disciplinary literature from social theory (Archer, 2012) moral psychology (Narvaez, 2009) and social psychology (Schwartz, 2010), we present a theoretical model that illustrates the psychological process of the (M)TP, thus contributing to the growing literature on the microfoundations of CSR

Does organizational formalization facilitate voice and helping organizational citizenship behaviors? It depends on (national) uncertainty norms

Prosocial work behaviors in a globalized environment do not operate in a cultural vacuum. We assess to what extent voice and helping organizational citizenship behaviors (OCBs) vary across cultures, depending on employees’ perceived level of organizational formalization and national uncertainty. We predict that in contexts of uncertainty, cognitive resources are engaged in coping with this uncertainty. Organizational formalization can provide structure that frees up cognitive resources to engage in OCB. In contrast, in contexts of low uncertainty, organizational formalization is not necessary for providing structure and may increase constraints on discretionary behavior. A three-level hierarchical linear modeling analysis of data from 7,537 employees in 267 organizations across 17 countries provides broad support for our hypothesis: perceived organizational formalization is weakly related to OCB, but where uncertainty is high; formalization facilitates voice significantly, helping OCB to a lesser extent. Our findings contribute to clarifying the dynamics between perceptions of norms at organizational and national levels for understanding when employees may engage in helping and voice behaviors. The key implication is that managers can foster OCB through organizational formalization interventions in uncertain environments that are cognitively demanding

Regulator Vulnerabilities to Political Pressure and Political Tie Intensity: The Moderating Effects of Regulatory and Political Distance

This study applies the institution-based view and neo-institutional theory in addressing how managerial perceptions of regulator vulnerabilities to political pressure, and institutional distance, influence intensification of political ties. Our analysis of 181 wholly owned foreign subsidiary (WOFSs) operating in the Philippines suggests that managerial perceptions of regulator vulnerability to political pressures positively enhance the intensification of political ties. Our results also reveal that regulatory distance and, more importantly, the simultaneous presence of political and regulatory distance diminish the positive relationship between managerial perceptions of regulator vulnerability to political pressures and a WOFS’s propensity to enhance the intensification of political ties. Managerial implications and future research directions are discusse

The Interactions of Institutions on Foreign Market Entry Mode

This paper examines the interaction effects of institutional differences in the cognitive, normative, and regulatory domains on cross-border acquisition and alliance formation. Using a sample of 673 cross-border acquisitions and alliances conducted by multinational corporations (MNCs) from the manufacturing sector of six emerging economies (EEs) over the period 1995–2008, we find significant mimicking (cognitive domain) of local firms' choice of ownership modes by EE firms. We also find that regulatory distance (regulatory domain) moderates the mimicking of both foreign and local firms while normative distance does not have any moderating effect. These findings contribute to our understanding of how EE MNCs mimic ownership modes in foreign market entry and how the interaction of this mimetic tendency with other institutional pillars affects these decision

A practical approach for EKF-SLAM in an indoor environment: fusing ultrasonic sensors and stereo camera

Improving the practical capability of SLAM requires effective sensor fusion to cope with the large uncertainties from the sensors and environment. Fusing ultrasonic and vision sensors possesses advantages of both economical efficiency and complementary cooperation. In particular, it can resolve the false data association and divergence problem of an ultrasonic sensor-only algorithm and overcome both the low frequency of SLAM update caused by the computational burden and the weakness to illumination changes of a vision sensor-only algorithm. In this paper, we propose a VR-SLAM (Vision and Range sensor-SLAM) algorithm to combine ultrasonic sensors and stereo camera very effectively. It consists of two schemes: (1) extracting robust point and line features from sonar data and (2) recognizing planar visual objects using a multi-scale Harris corner detector and its SIFT descriptor from a pre-constructed object database. We show that fusing these schemes through EKF-SLAM frameworks can achieve correct data association via the object recognition and high frequency update via the sonar features. The performance of the proposed algorithm was verified by experiments in various real indoor environments.X1127sciescopu