4,064 research outputs found

    Fermionic phase transition induced by the effective impurity in holography

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    We investigate the holographic fermionic phase transition induced by the effective impurity in holography, which is introduced by massless scalar fields in Einstein-Maxwell-massless scalar gravity. We obtain a phase diagram in (α,T)(\alpha, T) plane separating the Fermi liquid phase and the non-Fermi liquid phase.Comment: 17 pages, 9 figure

    Methanotrophic abundance and community fingerprint in pine and tea plantation soils as revealed by molecular methods

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    Understanding the community structure of methane-oxidizing bacteria (methanotrophs) is important to assess the microbial oxidation of the greenhouse gas methane (CH4) in soil under different land uses. Soil samples were collected from two plantation plots of pine and tea in southern China. Methanotrophic abundance was quantified with quantitative real-time polymerase chain reaction (qPCR) based on the 16S rRNA and pmoA genes, and the community fingerprint was characterized with denaturing gradient gel electrophoresis (DGGE) targeting the pmoA gene. No significant difference in the gene copy numbers of methanotrophs was found between the pine and tea land-use, regardless of 16S rRNA and pmoA genes. Higher abundance of type I (1.35 vs 1.66×108 copie g-1 soil) over type II methanotrophs (8.59 vs 10.9 × 107) were found both in pine and tea plantation soils. Apparent differences in methanotrophic community fingerprint were observed between the pine and tea treatments. Correlations analysis between methanotrophic abundance and soil characteristics, combining with canonial correspondence analysis (CCA) regarding community fingerprint and environmental parameters indicated that soil pH and available phosphorus were the most important factors potentially affecting the methanotrophic community diversity in the acidic red soil.Key words: Denaturing gradient gel electrophoresis (DGGE), land use, methanotrophs, pmoA gene, quantitative real-time PCR (qPCR)

    Holographic fermions in charged Lifshitz theory

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    We investigate the properties of holographic fermions in charged Lifshitz black holes at finite temperature through the AdS/CFT correspondence. In the charged Lifshitz background with the dynamical exponent z=2z=2, we find that the dispersion relation is linear. The scaling behavior of the imaginal part of the Green function relative to k=kkFk_{\perp}=k-k_F is also discussed. We find, although the system has linear dispersion relation and quadratic quasi-particle width, it does not satisfy Luttinger's theorem. We also find that the variation of the scaling parameters α\alpha and β\beta is small as the charge qq varies. Furthermore, we also discuss the effect of the dynamical exponent zz by considering the cases z=4z=4 and z=6z=6 and show that ImGiiImG_{ii} become smooth when the dynamical exponent zz increases.Comment: 1+16pages, many figures, published versio

    Holographic Fermions in Anisotropic Einstein-Maxwell-Dilaton-Axion Theory

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    We investigate the properties of the holographic Fermionic system dual to an anisotropic charged black brane bulk in Einstein-Maxwell-Dilaton-Axion gravity theory. We consider the minimal coupling between the Dirac field and the gauge field in the bulk gravity theory and mainly explore the dispersion relation exponents of the Green functions of the dual Fermionic operators in the dual field theory. We find that along both the anisotropic and the isotropic directions the Fermi momentum will be effected by the anisotropy of the bulk theory. However, the anisotropy has influence on the dispersion relation which is almost linear for massless Fermions with charge q=2. The universal properties that the mass and the charge of the Fermi possibly correspond to nonlinear dispersion relation are also investigated

    Research on Winding System of Twisting Machine Based on Multi-parameters

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    Winding movement of twisting machine is closely related to the package build, package density and yarn quality. The requirements are that the package build is good shaped and the winding tension is proper technically. Namely the angle of winding is fine and there is no overlapping and convex, hard edge on the package. The winding density is same and reasonable on the whole package build. And the fluctuation of winding tension is small. It is becoming development trend that driving of multiple-motors is used on twisting machine. There are many parameters to be controlled such as degree of twist, direction of twist, winding angle and spindle speed and so on. Therefore it is essential to set up reasonable mathematical model of yarn for winding movement

    catena-Poly[[[triaqua­(4,5-diaza­fluorene-9-one)cadmium]-μ-benzene-1,3-dicarboxyl­ato] dihydrate]

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    In the title compound, {[Cd(C8H4O4)(C11H6N2O)(H2O)3]·2H2O}n, the CdII atom is seven-coordinated by two N atoms from the phenanthroline-derived 4,5-diaza­fluorene-9-one ligand, two O atoms from one bidentate benzene-1,3-dicarboxyl­ate ligand and three O atoms from the three water mol­ecules in a distorted penta­gonal-bipyramidal arrangement. Moreover, there are two dissociative water mol­ecules in each unit. Neighbouring units inter­act through π–π inter­actions [centroid–centroid distances = 3.325 (3) and 3.358 (4) Å] and O—H⋯O hydrogen-bonding, resulting in a two-dimensional network extending parallel to (001)
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