Prediction of a large-gap quantum-spin-Hall insulator: Diamond-like GaBi bilayer

A quantum-spin-Hall (QSH) state was achieved experimentally, albeit at a low critical temperature because of the narrow band gap of the bulk material. Twodimensional topological insulators are critically important for realizing novel topological applications. Using density functional theory (DFT), we demonstrated that hydrogenated GaBi bilayers (HGaBi) form a stable topological insulator with a large nontrivial band gap of 0.320 eV, based on the state-of-the-art hybrid functional method, which is implementable for achieving QSH states at room temperature. The nontrivial topological property of the HGaBi lattice can also be confirmed from the appearance of gapless edge states in the nanoribbon structure. Our results provide a versatile platform for hosting nontrivial topological states usable for important nanoelectronic device applications.

Climbing the design ladder: Step by step

This research presents findings of a research project where the first author worked with a small to medium sized enterprise (SME) manufacturing company in order to integrate design at a strategic level within the company. This study aims to identify the changes experienced in the participating company while shifting the perspective of design from a product focus towards a strategic focus. Staff interviews at two points in time and a reflective journal were used as data sources within an action research methodology. A shift in the perspective of design was noted in three cultural changes within the firm over time: a focus on long term as well as short term outcomes, on indirect as well as direct value and on intangible as well as tangible benefits. These three components are proposed as ‘cultural stepping stones’ that describe how a company transitions from an exclusively product- focused utilisation of design, to a process-level application of design. Implications of this research are provided as considerations for businesses that are attempting to facilitate a similar transformation in the future.

Intra-cluster correlation structure in longitudinal data analysis: Selection criteria and misspecification tests

Selection criteria and misspecification tests for the intra-cluster correlation structure (ICS) in longitudinal data analysis are considered. In particular, the asymptotical distribution of the correlation information criterion (CIC) is derived and a new method for selecting a working ICS is proposed by standardizing the selection criterion as the p-value. The CIC test is found to be powerful in detecting misspecification of the working ICS structures, while with respect to the working ICS selection, the standardized CIC test is also shown to have satisfactory performance. Some simulation studies and applications to two real longitudinal datasets are made to illustrate how these criteria and tests might be useful.

Individual process management: A first step towards the conceptualization of individual activities

Understanding activities of individuals is of major importance because their actions are the main foundation of economic activity. However, there is a lack of understanding with regard to how individual activities are characterised. Thus, we develop a first conceptual classification for individual activities extending the view on business processes. The classification scheme contains personal care, education, professional work, domestic work, leisure and travel as primary activities and individual organization, procurement, information gathering and self-expression as secondary activities. We extend mainly prior literature on customer management by structuring processes of individuals independently from their status as customer. This enables new theoretical insights in the way companies can design their offers from a strategic point of view. Companies can use IPM to systematically analyze individual processes independent from specific products and services which is assumed to foster the development of innovative product and service offers.

The interaction of quantum dots with plasmons supported by metal waveguides

Plasmonics is a recently emerged technology that enables the compression of electromagnetic waves into miniscule metallic structures, thus enabling the focusing and routing of light on the nanoscale. Plasmonic waveguides can be used to miniaturise the size of integrated chip circuits while increasing the data transmission speed. Plasmonic waveguides are used to route the plasmons around a circuit and are a major focus of this thesis. Also, plasmons are highly sensitive to the surrounding dielectric environment. Using this property we have experimentally realised a refractive index sensor to detect refractive index change in solutions.

Step based physical activity guidelines for preschool-aged children

OBJECTIVE Public health organizations recommend that preschool-aged children accumulate at least 3h of physical activity (PA) daily. Objective monitoring using pedometers offers an opportunity to measure preschooler's PA and assess compliance with this recommendation. The purpose of this study was to derive step-based recommendations consistent with the 3h PA recommendation for preschool-aged children. METHOD The study sample comprised 916 preschool-aged children, aged 3 to 6years (mean age=5.0+/-0.8years). Children were recruited from kindergartens located in Portugal, between 2009 and 2013. Children wore an ActiGraph GT1M accelerometer that measured PA intensity and steps per day simultaneously over a 7-day monitoring period. Receiver operating characteristic (ROC) curve analysis was used to identify the daily step count threshold associated with meeting the daily 3hour PA recommendation. RESULTS A significant correlation was observed between minutes of total PA and steps per day (r=0.76, p<0.001). The optimal step count for >/=3h of total PA was 9099 steps per day (sensitivity (90%) and specificity (66%)) with area under the ROC curve=0.86 (95% CI: 0.84 to 0.88). CONCLUSION Preschool-aged children who accumulate less than 9000 steps per day may be considered Insufficiently Active.

An efficient and light-weight multi-tasking model to achieve Intra-Agent concurrency for SAGE

Multi-agent systems implicate a high degree of concurrency at both the Inter- and Intra-Agent levels. Scalable, fault tolerant, Agent Grooming Environment (SAGE), the second generation, FIPA compliant MAS requires a built in mechanism to achieve both the Inter- and Intra-Agent concurrency. This paper dilates upon an attempt to provide a reliable, efficient and light-weight solution to provide intra-agent concurrency with-in the internal agent architecture of SAGE. It addresses the issues related to using the JAVA threading model to provide this level of concurrency to the agent and provides an alternative approach that is based on an eventdriven, concurrent and user-scalable multi-tasking model for the agent's internal model. The findings of this paper show that our proposed approach is suitable for providing an efficient and lightweight concurrent task model for SA GE and considerably outweighs the performance of multithreaded tasking model based on JAVA in terms of throughput and efficiency. This has been illustrated using the practical implementation and evaluation of both models. © 2004 IEEE.

Two-step self-assembly of hierarchically-ordered nanostructures

Due to their unique size- and shape-dependent physical and chemical properties, highly hierarchically-ordered nanostructures have attracted great attention with a view to application in emerging technologies, such as novel energy generation, harvesting, and storage devices. The question of how to get controllable ensembles of nanostructures, however, still remains a challenge. This concept paper first summarizes and clarifies the concept of the two-step self-assembly approach for the synthesis of hierarchically-ordered nanostructures with complex morphology. Based on the preparation processes, two-step self-assembly can be classified into two typical types, namely, two-step self-assembly with two discontinuous processes and two-step self-assembly completed in one-pot solutions with two continuous processes. Compared to the conventional one-step self-assembly, the two-step self-assembly approach allows the combination of multiple synthetic techniques and the realization of complex nanostructures with hierarchically-ordered multiscale structures. Moreover, this approach also allows the self-assembly of heterostructures or hybrid nanomaterials in a cost-effective way. It is expected that widespread application of two-step self-assembly will give us a new way to fabricate multifunctional nanostructures with deliberately designed architectures. The concept of two-step self-assembly can also be extended to syntheses including more than two chemical/physical reaction steps (multiple-step self-assembly).

Tetragonal bismuth bilayer: A stable and robust quantum spin hall insulator

Topological insulators (TIs) exhibit novel physics with great promise for new devices, but considerable challenges remain to identify TIs with high structural stability and large nontrivial band gap suitable for practical applications. Here we predict by first-principles calculations a two-dimensional (2D) TI, also known as a quantum spin Hall (QSH) insulator, in a tetragonal bismuth bilayer (TB-Bi) structure that is dynamically and thermally stable based on phonon calculations and finite-temperature molecular dynamics simulations. Density functional theory and tight-binding calculations reveal a band inversion among the Bi-p orbits driven by the strong intrinsic spin-orbit coupling, producing a large nontrivial band gap, which can be effectively tuned by moderate strains. The helical gapless edge states exhibit a linear dispersion with a high Fermi velocity comparable to that of graphene, and the QSHphase remains robust on a NaCl substrate. These remarkable properties place TB-Bi among the most promising 2D TIs for high-speed spintronic devices, and the present results provide insights into the intriguing QSH phenomenon in this new Bi structure and offer guidance for its implementation in potential applications.

In-situ one-step hydrothermal synthesis of a lead germanate-graphene composite as a novel anode material for lithium-ion batteries

Lead germanate-graphene nanosheets (PbGeO3-GNS) composites have been prepared by an efficient one-step, in-situ hydrothermal method and were used as anode materials for Li-ion batteries (LIBs). The PbGeO3 nanowires, around 100–200 nm in diameter, are highly encapsulated in a graphene matrix. The lithiation and de-lithiation reaction mechanisms of the PbGeO3 anode during the charge-discharge processes have been investigated by X-ray diffraction and electrochemical characterization. Compared with pure PbGeO3 anode, dramatic improvements in the electrochemical performance of the composite anodes have been obtained. In the voltage window of 0.01–1.50 V, the composite anode with 20 wt.% GNS delivers a discharge capacity of 607 mAh g−1 at 100 mA g−1 after 50 cycles. Even at a high current density of 1600 mA g−1, a capacity of 406 mAh g−1 can be achieved. Therefore, the PbGeO3-GNS composite can be considered as a potential anode material for lithium ion batteries.

Robust superhydrophobicity of hierarchical ZnO hollow microspheres fabricated by two-step self-assembly

Superhydrophobic and superhydrophilic surfaces have been extensively investigated due to their importance for industrial applications. It has been reported, however, that superhydrophobic surfaces are very sensitive to heat, ultraviolet (UV) light, and electric potential, which interfere with their long-term durability. In this study, we introduce a novel approach to achieve robust superhydrophobic thin films by designing architecture-defined complex nanostructures. A family of ZnO hollow microspheres with controlled constituent architectures in the morphologies of 1D nanowire networks, 2D nanosheet stacks, and 3D mesoporous nanoball blocks, respectively, was synthesized via a two-step self-assembly approach, where the oligomers or the constituent nanostructures with specially designed structures are first formed from surfactant templates, and then further assembled into complex morphologies by the addition of a second co-surfactant. The thin films composed of two-step synthesized ZnO hollow microspheres with different architectures presented superhydrophobicities with contact angles of 150°-155°, superior to the contact angle of 103° for one-step synthesized ZnO hollow microspheres with smooth and solid surfaces. Moreover, the robust superhydrophobicity was further improved by perfluorinated silane surface modification. The perfluorinated silane treated ZnO hollow microsphere thin films maintained excellent hydrophobicity even after 75 h of UV irradiation. The realization of environmentally durable superhydrophobic surfaces provides a promising solution for their long-term service under UV or strong solar light irradiations.

Tailoring texture of γ-Y2Si2O7 by strong magnetic field alignment and two-step sintering

In this study, a well-dispersed γ-Y2Si2O 7 ethanol-based suspension with 30 vol% solid loading was prepared by adding 1 dwb% polyethylene imine dispersant, which allows feeble magnetic γ-Y2Si2O7 particles with anisotropic magnetic susceptibility to rotate in a 12 T strong magnetic field during slip casting, resulting in the development of a strong texture in green bodies. Pressureless sintering gives rise to more pronounced grain growth in the textured sample than in the untextured sample prepared without the magnetic field due to the rapid migration of the grain boundaries of the well-oriented grains, which was revealed by constant-heating-rate sintering kinetics. It was found that the use of two-step sintering is very efficient not only for inhibiting the grain growth but also for enhancing the texture. This implies that controlled grain growth is crucial for enhancing texture development in γ-Y2Si2O7.

Modelling Cued-Target Recall using Quantum Inspired Models of Target Activation

This article presents and evaluates Quantum Inspired models of Target Activation using Cued-Target Recall Memory Modelling over multiple sources of Free Association data. Two components were evaluated: Whether Quantum Inspired models of Target Activation would provide a better framework than their classical psychological counterparts and how robust these models are across the different sources of Free Association data. In previous work, a formal model of cued-target recall did not exist and as such Target Activation was unable to be assessed directly. Further to that, the data source used was suspected of suffering from temporal and geographical bias. As a consequence, Target Activation was measured against cued-target recall data as an approximation of performance. Since then, a formal model of cued-target recall (PIER3) has been developed [10] with alternative sources of data also becoming available. This allowed us to directly model target activation in cued-target recall with human cued-target recall pairs and use multiply sources of Free Association Data. Featural Characteristics known to be important to Target Activation were measured for each of the data sources to identify any major differences that may explain variations in performance for each of the models. Each of the activation models were used in the PIER3 memory model for each of the data sources and was benchmarked against cued-target recall pairs provided by the University of South Florida (USF). Two methods where used to evaluate performance. The first involved measuring the divergence between the sets of results using the Kullback Leibler (KL) divergence with the second utilizing a previous statistical analysis of the errors [9]. Of the three sources of data, two were sourced from human subjects being the USF Free Association Norms and the University of Leuven (UL) Free Association Networks. The third was sourced from a new method put forward by Galea and Bruza, 2015 in which pseudo Free Association Networks (Corpus Based Association Networks - CANs) are built using co-occurrence statistics on large text corpus. It was found that the Quantum Inspired Models of Target Activation not only outperformed the classical psychological model but was more robust across a variety of data sources.