Correlation effects in the electronic structure of the Ni-based superconducting KNi2S2

The LDA plus Gutzwiller variational method is used to investigate the groundstate physical properties of the newly discovered superconducting KNi2S2. Five Ni-3d Wannier-orbital basis are constructed by the density-functional theory, to combine with local Coulomb interaction to describe the normal state electronic structure of Ni-based superconductor. The band structure and the mass enhanced are studied based on a multiorbital Hubbard model by using Gutzwiller approximation method. Our results indicate that the correlation effects lead to the mass enhancement of KNi2S2. Different from the band structure calculated from the LDA results, there are three energy bands across the Fermi level along the X-Z line due to the existence of the correlation effects, which induces a very complicated Fermi surface along the X-Z line. We have also investigated the variation of the quasi-particle weight factor with the hole or electron doping and found that the mass enhancement character has been maintained with the doping.Comment: 12 pages, 6 figure

Closed-loop supply chain coordination based on recyclers\u27 competition model

In a closed-loop supply chain led by manufacturing enterprises, there are often two or more recyclers that are very competitive among each other. The manufacturer may also provide many recycling contracts in order to identify recyclers’ private information. This paper examines a closed-loop supply chain consisting of a manufacturer at the core of the supply chain and two competing recyclers. In order to strike a balance between its own interest and overall interest manufacturer provides two different recycling contracts: price contract and quantity contract. Two situations have been analyzed in this paper: the first in which only advantage recycler adopts quantity contract and the second in which both recyclers adopt quantity contract. A numerical simulation has been carried out according to some current data of an enterprise. In case in which the advantage recycler adopts quantity contract and the inferior recycler adopts price contract, the closed-loop supply chain has reached its equilibrium and the interests of all parties have been balanced

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

Cooling mechanical resonators to quantum ground state from room temperature

Ground-state cooling of mesoscopic mechanical resonators is a fundamental requirement for test of quantum theory and for implementation of quantum information. We analyze the cavity optomechanical cooling limits in the intermediate coupling regime, where the light-enhanced optomechanical coupling strength is comparable with the cavity decay rate. It is found that in this regime the cooling breaks through the limits in both the strong and weak coupling regimes. The lowest cooling limit is derived analytically at the optimal conditions of cavity decay rate and coupling strength. In essence, cooling to the quantum ground state requires $Q_{\mathrm{m}}>2.4n_{\mathrm{th}}$, with $Q_{\mathrm{m}}$ being the mechanical quality factor and $n_{\mathrm{th}}$ being the thermal phonon number. Remarkably, ground-state cooling is achievable starting from room temperature, when mechanical $Q$-frequency product $Q_{\mathrm{m}}{\nu>1.5}\times10^{13}$, and both of the cavity decay rate and the coupling strength exceed the thermal decoherence rate. Our study provides a general framework for optimizing the backaction cooling of mesoscopic mechanical resonators

SUSTAINABILITYAND GROWTH OFONLINE KNOWLEDGE COMMUNITIES: EXAMINING THE IMPORTANCE OFPERCEIVED COMMUNITYSUPPORTAND PERCEIVED LEADER SUPPORT

Voluntary behaviors (i.e., knowledge contribution and word of mouth) are important to the sustainability and growth of online knowledge communities. Although previous studies have identified various factors leading to knowledge contribution and related behaviors, the underlying psychological processes have rarely been examined. In particular, previous studies have not examined how characteristics of online knowledge communities influence voluntary behaviors through support perception. This study aims to fill the gap in the literature by developing and testing a model to explain voluntary behaviors in online knowledge communities. To develop the research model, we drew on theories of justice, organizational support, and citizenship behavior to explain the influence of characteristics of online knowledge communities on individuals\u27 voluntary behaviors through their perceptions of support from the community and the leader. The research model was tested on survey data collected from 214 online knowledge community users. The results largely supported our model. In particular, we found that pro-sharing norm and information need fulfillment affect perceived community support. Perceived recognition from leader and perceived co-presence of leader affect perceived leader support. Additionally, perceived community support was found to be important in shaping knowledge contribution and word of mouth. Perceived leader support was found to influence individuals\u27 knowledge contribution behavior. Theoretical and Practical implications are discussed

Bi- and tri-dentate imino-based iron and cobalt pre-catalysts for ethylene oligo-/polymerization

Recent progress on the use of iron and cobalt complex pre-catalysts for ethylene reactivity is reviewed. The review is organized in terms of the denticity of the chelate ligands employed, with particular reference to the influence of the ligand frameworks and their substituents on the catalytic performance for ethylene oligomerization/polymerization catalysis. The majority of the systems bear tri-dentate ligation at the iron/cobalt centre, though it is clear that bi-dentate iron/cobalt complex pre-catalysts have also attracted significant attention. Such systems produce in most cases highly linear products ranging from oligomeric α-olefins to high molecular weight polyethylene, and as such are promising candidates for both academic and industrial considerations

Application of Metabolomics in Traditional Chinese Medicine Differentiation of Deficiency and Excess Syndromes in Patients with Diabetes Mellitus

Metabolic profiling is widely used as a probe in diagnosing diseases. In this study, the metabolic profiling of urinary carbohydrates was investigated using gas chromatography/mass spectrometry (GC/MS) and multivariate statistical analysis. The kernel-based orthogonal projections to latent structures (K-OPLS) model were established and validated to distinguish between subjects with and without diabetes mellitus (DM). The model was combined with subwindow permutation analysis (SPA) in order to extract novel biomarker information. Furthermore, the K-OPLS model visually represented the alterations in urinary carbohydrate profiles of excess and deficiency syndromes in patients with diabetes. The combination of GC/MS and K-OPLS/SPA analysis allowed the urinary carbohydrate metabolic characterization of DM patients with different traditional Chinese medicine (TCM) syndromes, including biomarkers different from non-DM patients. The method presented in this study might be a complement or an alternative to TCM syndrome research

Expressions of ECE-CYC2 clade genes relating to abortion of both dorsal and ventral stamens in Opithandra (Gesneriaceae)

<p>Abstract</p> <p>Background</p> <p>ECE-CYC2 clade genes known in patterning floral dorsoventral asymmetry (zygomorphy) in <it>Antirrhinum majus </it>are conserved in the dorsal identity function including arresting the dorsal stamen. However, it remains uncertain whether the same mechanism underlies abortion of the ventral stamens, an important morphological trait related to evolution and diversification of zygomorphy in Lamiales <it>sensu lato</it>, a major clade of predominantly zygomorphically flowered angiosperms. <it>Opithandra </it>(Gesneriaceae) is of particular interests in addressing this question as it is in the base of Lamiales <it>s.l</it>., an early representative of this type zygomorphy.</p> <p>Results</p> <p>We investigated the expression patterns of four ECE-CYC2 clade genes and two putative target <it>cyclinD3 </it>genes in <it>Opithandra </it>using RNA <it>in situ </it>hybridization and RT-PCR. <it>OpdCYC </it>gene expressions were correlated with abortion of both dorsal and ventral stamens in <it>Opithandra</it>, strengthened by the negatively correlated expression of their putative target <it>OpdcyclinD3 </it>genes. The complement of <it>OpdcyclinD3 </it>to <it>OpdCYC </it>expressions further indicated that <it>OpdCYC </it>expressions were related to the dorsal and ventral stamen abortion through negative effects on <it>OpdcyclinD3 </it>genes.</p> <p>Conclusion</p> <p>These results suggest that ECE-CYC2 clade TCP genes are not only functionally conserved in the dorsal stamen repression, but also involved in arresting ventral stamens, a genetic mechanism underlying the establishment of zygomorphy with abortion of both the dorsal and ventral stamens evolved in angiosperms, especially within Lamiales <it>s.l</it>.</p