4,998 research outputs found

    Polarization Dependence of Raman Spectra in Strained Graphene

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    The polarization dependences of the G, D, and 2D (G′') bands in Raman spectra at graphene bulk and edge are examined theoretically. The 2D and D bands have different selection rules at bulk and edge. At bulk, the 2D band intensity is maximum when the polarization of the scattered light is parallel to that of incident light, whereas the D band intensity does not have a polarization dependence. At edge, the 2D and D bands exhibit a selection rule similar to that of the G band proposed in a previous paper. We suggest that a constraint equation on the axial velocity caused by the graphene edge is essential for the dependence of the G band on the crystallographic orientation observed in the bulk of strained graphene. This is indicative of that the pseudospin and valleyspin in the bulk of graphene can not be completely free from the effect of surrounding edge. The status of the experiments on the G and D bands at the graphene edge is mentioned.Comment: 11 pages, 3 figure

    Evaluation of scanning earth sensor mechanism on engineering test satellite 4

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    The results of the analysis and the evaluation of flight data obtained from the horizon sensor test project are described. The rotary mechanism of the scanning earth sensor composed of direct drive motor and bearings using solid lubricant is operated satisfactorily. The transmitted flight data from Engineering Test Satellite IV was evaluated in comparison with the design value

    Streptococcus pyogenes Superantigens: Studies Into Host Specificity and Functional Redundancy

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    Streptococcus pyogenes is a human-specific globally prominent bacterial pathogen that secretes extremely potent exotoxins known as superantigens. Superantigens function to overstimulate T lymphocytes, capable of inducing excessive cytokine responses, potentially leading to toxic shock syndrome. Each strain of S. pyogenes encodes multiple distinct superantigens, yet the reasons why S. pyogenes retains multiple superantigens has remained elusive. Using a murine model of acute nasopharyngeal infection, the role of each superantigen encoded by S. pyogenes MGAS5005 was evaluated using isogenic superantigen-deletion or -complemented strains, and passive immunization with superantigen-neutralizing antibodies. The superantigen SpeG, and likely SpeJ, were not required for infection. However, SpeA and SmeZ were both required for infection of HLA-DQ8 transgenic mice, and thus, are not functionally redundant. This supports the theory that S. pyogenes superantigen expression varies depending on host factors, and provides insight into superantigen function in non-severe infections

    Multi-layer structure of mid-latitude sporadic-<i>E</i> observed during the SEEK-2 campaign

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    In the mid-latitude ionospheric region, sporadic-<i>E</i> layers (<i>E<sub>s</sub></i> layers) have often been observed, revealing multiple layers. The <i>E<sub>s</sub></i> layers observed during the SEEK-2 rocket campaign showed double electron density peaks; namely, there are stable lower peaks and relatively unstable upper peaks. We examined the effects of wind shear and the electric fields on the generation of the multiple layer structure, in comparison with the electron density profile, the neutral wind, and the DC electric field observed by the S310 rocket experiments. The results showed that the neutral wind shear is mainly responsible for the generation of the lower layer, while the DC electric field makes a significant contribution to the formation of the upper layer. The difference between the lower and upper layers was also explained by the enhanced AC electric field observed at about 103–105 km altitude. The external DC electric field intensity is expected to be ~5 mV/m, which is enough to contribute to generate the <i>E<sub>s</sub></i> layers in the ionosphere.<br><br> <b>Keywords.</b> Ionosphere (Electric fields; Ionospheric irregularities, Mid-latitude ionosphere

    Chalker-Coddington model described by an S-matrix with odd dimensions

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    The Chalker-Coddington network model is often used to describe the transport properties of quantum Hall systems. By adding an extra channel to this model, we introduce an asymmetric model with profoundly different transport properties. We present a numerical analysis of these transport properties and consider the relevance for realistic systems.Comment: 7 pages, 4 figures. To appear in the EP2DS-17 proceeding
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