4,797 research outputs found
Anderson Impurity in Helical Metal
We use a trial wave function to study the spin-1/2 Kondo effect of a helical
metal on the surface of a three-dimensional topological insulator. While the
impurity spin is quenched by conduction electrons, the spin-spin correlation of
the conduction electron and impurity is strongly anisotropic in both spin and
spatial spaces. As a result of strong spin-orbit coupling, the out-of-plane
component of the impurity spin is found to be fully screened by the orbital
angular momentum of the conduction electrons.Comment: The published versio
Leptophilic dark matter in gauged model in light of DAMPE cosmic ray excess
Motivated by the very recent cosmic-ray electron+positron excess observed by
DAMPE collaboration, we investigate a Dirac fermion dark matter (DM) in the
gauged model. DM interacts with the electron and muon via the
gauge boson . The model can explain the DAMPE data well.
Although a non-zero DM-nucleon cross section is only generated at one loop
level and there is a partial cancellation between and
couplings, we find that a large portion of mass is ruled out from
direct DM detection limit leaving the allowed mass to be close to two
times of the DM mass. Implications for and , and muon anomaly are also studied.Comment: Discussions added, version accepted by EPJ
The effects of the late 2000s global financial crisis on Australia’s construction demand
An accurate measurement of the impacts of external shocks on construction demand will enable construction industry policymakers and developers to make allowances for future occurrences and advance the construction industry in a sustainable manner. This paper aims to measurethe dynamic effects of the late 2000s global financial crisis on the level of demand in the Australian construction industry. The vector error correction (VEC) model with intervention indicators is employed to estimate the external impact from the crisis on a macro-level construction economic indicator, namely construction demand. The methodology comprises six main stages to produce appropriate VEC models that describe the characteristics of the underlying process. Research findings suggestthat overall residential and non-residential construction demand were affected significantly by the recent crisis and seasonality. Non-residentialconstruction demand was disrupted more than residential construction demand at the crisis onset. The residential constructionindustry is more reactive and is able to recover faster following the crisis in comparison with the non-residential industry. The VEC model with intervention indicators developed in this study can be used as an experiment for an advanced econometric method. This can be used to analyse the effects of special eventsand factors not only on construction but also on other industries
Recent advance in direct sp3 carbon-hydrogen bond functionalizations
Direct and selective carbon-hydrogen bond functionalization has attracted enormous attention because it provides more efficient strategies for preparing valuable functional molecules from easily available substrates. Significant and exciting developments in functionalization of un-activation Csp3-H bonds have continuously been made over the past few decades. This review mainly summarizes recent advances on direct Csp3-H bond functionalization for the formation of C-C and C-heteroatom bond under transition-metal-catalysed and metal-free conditions
Systematic investigation of the rotational bands in nuclei with using a particle-number conserving method based on a cranked shell model
The rotational bands in nuclei with are investigated
systematically by using a cranked shell model (CSM) with the pairing
correlations treated by a particle-number conserving (PNC) method, in which the
blocking effects are taken into account exactly. By fitting the experimental
single-particle spectra in these nuclei, a new set of Nilsson parameters
( and ) and deformation parameters ( and
) are proposed. The experimental kinematic moments of inertia
for the rotational bands in even-even, odd- and odd-odd nuclei, and the
bandhead energies of the 1-quasiparticle bands in odd- nuclei, are
reproduced quite well by the PNC-CSM calculations. By analyzing the
-dependence of the occupation probability of each cranked Nilsson
orbital near the Fermi surface and the contributions of valence orbitals in
each major shell to the angular momentum alignment, the upbending mechanism in
this region is understood clearly.Comment: 21 pages, 24 figures, extended version of arXiv: 1101.3607 (Phys.
Rev. C83, 011304R); added refs.; added Fig. 4 and discussions; Phys. Rev. C,
in pres
Plant diversity of Southeast Asia-II
The special issue of plant diversity in Southeast Asia will focus on the documentation of new discoveries in SE Asia. There are four global biodiversity hotspots in Southeast Asia. Although there are many plans to protect this rich biodiversity, however, the rich biodiversity in SE Asia is under threat due to economic development and population growth. There is a huge gap between our knowledge and biodiversity in SE Asia. During the last six investigations, many new taxa, including new species, new genera, have been discovered. This special issue will bring the rich but little known biodiversity to the public and protect them
MULTI AGV SCHEDULING PROBLEM IN AUTOMATED CONTAINER TERMINAL
ABSTRACT In this paper we propose a dynamic multi automated guided vehicle (AGV) scheduling method based on the scheduling properties of automated container terminal handling systems. In multi-AGV scheduling, the composition of AGV handling time and the precedence order of certain tasks are major constraints. Taking these into consideration, we design a genetic algorithm (GA) for a dynamic multi-AGV scheduling model to minimize completion time and standard deviation of handling time of quay cranes (QC), and validated the proposed model through numerical experiment. We expect this model to be significant for multi-agent scheduling of discrete production systems
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