Electronic States and Magnetism of Mn Impurities and Dimers in Narrow-Gap and Wide-Gap III-V Semiconductors

Electronic states and magnetic properties of single $Mn$ impurity and dimer doped in narrow-gap and wide-gap $III$-$V$ semiconductors have been studied systematically. It has been found that in the ground state for single $Mn$ impurity, $Mn$-$As(N)$ complex is antiferromagnetic (AFM) coupling when $p$-$d$ hybridization $V_{pd}$ is large and both the hole level $E_{v}$ and the impurity level $E_{d}$ are close to the midgap; or very weak ferromagnetic (FM) when $V_{pd}$ is small and both $E_{v}$ and $E_d$ are deep in the valence band. In $Mn$ dimer situation, the $Mn$ spins are AFM coupling for half-filled or full-filled $p$ orbits; on the contrast, the Mn spins are double-exchange-like FM coupling for any $p$-orbits away from half-filling. We propose the strong {\it p-d} hybridized double exchange mechanism is responsible for the FM order in diluted $III$-$V$ semiconductors

Understanding the Double-Level Influence of Guanxi on Construction Innovation in China: The Mediating Role of Interpersonal Knowledge Sharing and the Cross-Level Moderating Role of Inter-Organizational Relationships

Guanxi, a Chinese term that defines social networks of power and benefits, can be divided into inter-personal and inter-organizational relationships. Guanxi significantly influences construction innovation in China. Many studies have examined the relationship between guanxi and construction innovation at the project or organizational level. However, few of these studies explain how guanxi might affect an individual’s innovative behaviour from a double-level perspective. This paper builds on social capital theory and social exchange theory to examine guanxi’s role in motivating innovative behaviour in a China-specific construction context. It investigates the main effects of inter-personal relationships on innovative behaviour, the mediating effects of knowledge sharing, and the cross-level moderating effects of inter-organizational relationships. These elements were tested using a survey that received 178 responses from 35 different organizations. The results were analysed using Hierarchical Linear Modelling (HLM) and revealed that inter-personal relationships have positive influences on innovative behaviour, thus highlighting the partial mediating effects of knowledge sharing. In addition, the analyses showed that inter-organizational relationships augment inter-personal relationships and knowledge sharing on innovative behaviour by cross-level interaction. The research findings enhance an understanding of guanxi and innovative behaviour in China-specific construction project settings, as well as verifying the significance of guanxi in stimulating innovative behaviour

IoTBeholder: A Privacy Snooping Attack on User Habitual Behaviors from Smart Home Wi-Fi Traffic

With the deployment of a growing number of smart home IoT devices, privacy leakage has become a growing concern. Prior work on privacy-invasive device localization, classification, and activity identification have proven the existence of various privacy leakage risks in smart home environments. However, they only demonstrate limited threats in real world due to many impractical assumptions, such as having privileged access to the user's home network. In this paper, we identify a new end-to-end attack surface using IoTBeholder, a system that performs device localization, classification, and user activity identification. IoTBeholder can be easily run and replicated on commercial off-the-shelf (COTS) devices such as mobile phones or personal computers, enabling attackers to infer user's habitual behaviors from smart home Wi-Fi traffic alone. We set up a testbed with 23 IoT devices for evaluation in the real world. The result shows that IoTBeholder has good device classification and device activity identification performance. In addition, IoTBeholder can infer the users' habitual behaviors and automation rules with high accuracy and interpretability. It can even accurately predict the users' future actions, highlighting a significant threat to user privacy that IoT vendors and users should highly concern

Evolution of InAs branches in InAs/GaAs nanowire heterostructures

Branched nanowireheterostructures of InAs∕GaAs were observed during Au-assisted growth of InAs on GaAsnanowires. The evolution of these branches has been determined through detailed electron microscopy characterization with the following sequence: (1) in the initial stage of InAsgrowth, the Au droplet is observed to slide down the side of the GaAsnanowire, (2) the downward movement of Aunanoparticle later terminates when the nanoparticle encounters InAsgrowing radially on the GaAsnanowire sidewalls, and (3) with further supply of In and As vapor reactants, the Aunanoparticles assist the formation of InAs branches with a well-defined orientation relationship with GaAs∕InAs core/shell stems. We anticipate that these observations advance the understanding of the kink formation in axial nanowireheterostructures.The Australian Research Council is acknowledged for the financial support of this project. One of the authors M.P. acknowledges the support of an International Postgraduate Research Scholarship

From work resources to safety performance: tour guides\u27 job burnout and personality profiles matter

Tour guides play an integral role in ensuring safe tourism; however, exactly how to improve tour guides’ safety performance remains unclear. Two studies were conducted in this research to investigate how an external factor (i.e., work resources) and an internal factor (i.e., individual situational awareness [ISA]) interact to affect safety performance. Results showed that work resources significantly influenced tour guides’ safety performance, with this effect being partially mediated by ISA. Job burnout moderated the relationship between ISA and safety performance. A multi-group analysis was performed to examine the moderating impacts of tour guides’ personality profiles. Tour guides with the ‘resilient’ profile appeared more capable of transforming work resources into ISA. These findings bolster knowledge of tourism safety management and offer practical recommendations for tour guide recruitment, management, and training to enhance group tour safety

Simultaneous Saccharification and Fermentation of Corn Straw to Lactic Acid

The utilization of corn straw to produce lactic acid could largely save the resource as well as decrease the amount of agricultural waste. In this study, orthogonal experimental design was adopted to investigate the optimum conditions for cellulase production from corn straw, and then the cellulase was further used to produce lactic acid through simultaneous saccharification and fermentation (SSF) process. (NH4)2SO4 and Tween 80 were also used to test their effects on lactic acid production. The optimum conditions were determined as follows: solid-to-liquid ratio was ζ = 1 : 3, pH of the substrate mixture was 4.5, inoculum size of Trichoderma koningii was G = 12 % (v/m), fermentation time was t = 84 h. Corresponding maximum cellulase of H = 2630.3 U g–1 straw was achieved. With the produced cellulase added, the maximum lactic acid concentration of γ = 20.2 g L–1 could be achieved inoculated with lactic acid bacteria T50 at θ = 45 °C. As compared with control (non-addition), addition of w = 2 % (NH4)2SO4 could increase the lactic acid by 3.6 %, while addition of Tween 80 could shorten the fermentation time from t = 108 h to t = 72 h. The result indicated that utilization of corn straw as substrate to produce cellulase and lactic acid was applicable and could reduce pollution, thus this was worth investigating further

Observation of indirect ionization of W7+ in an electron-beam ion-trap plasma

In this work, visible and extreme ultraviolet spectra of W7+ are measured using the high-temperature superconducting electron-beam ion trap (EBIT) at the Shanghai EBIT Laboratory under extremely low-energy conditions (lower than the nominal electron-beam energy of 130 eV). The relevant atomic structure is calculated using the flexible atomic code package based on the relativistic configuration interaction method. The GRASP2K code, in the framework of the multiconfiguration Dirac-Hartree-Fock method, is employed as well for calculating the wavelength of the M1 transition in the ground configuration of W7+. A line from the W7+ ions is observed at a little higher electron-beam energy than the ionization potential for W4+, making this line appear to be from W5+. A hypothesis for the charge-state evolution of W7+ is proposed based on our experimental and theoretical results; that is, the occurrence of W7+ ions results from indirect ionization caused by stepwise excitation between some metastable states of lower-charge-state W ions, at the nominal electron-beam energy of 59 eV

Strong decays of N∗(1535)N^{*}(1535) in an extended chiral quark model

The strong decays of the $N^{*}(1535)$ resonance are investigated in an extended chiral quark model by including the low-lying $qqqq\bar{q}$ components in addition to the $qqq$ component. The results show that these five-quark components in $N^{*}(1535)$ contribute significantly to the $N^{*}(1535)\to N\pi$ and $N^{*}(1535)\to N\eta$ decays. The contributions to the $N\eta$ decay come from both the lowest energy and the next-to-lowest energy five-quarks components, while the contributions to the $N\pi$ decay come from only the latter one. Taking these contributions into account, the description for the strong decays of $N^{*}(1535)$ is improved, especially, for the puzzling large ratio of the decays to $N\eta$ and $N\pi$.Comment: 6 pages, 1 figur