108 research outputs found

    Simulated Nanoscale Peeling Process of Monolayer Graphene Sheet - Effect of Edge Structure and Lifting Position

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    The nanoscale peeling of the graphene sheet on the graphite surface is numerically studied by molecular mechanics simulation. For center-lifting case, the successive partial peelings of the graphene around the lifting center appear as discrete jumps in the force curve, which induce the arched deformation of the graphene sheet. For edge-lifting case, marked atomic-scale friction of the graphene sheet during the nanoscale peeling process is found. During the surface contact, the graphene sheet takes the atomic-scale sliding motion. The period of the peeling force curve during the surface contact decreases to the lattice period of the graphite. During the line contact, the graphene sheet also takes the stick-slip sliding motion. These findings indicate the possibility of not only the direct observation of the atomic-scale friction of the graphene sheet at the tip/surface interface but also the identification of the lattice orientation and the edge structure of the graphene sheet

    Numerically designed phase-mask for stellar coronagraph

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    Phase-mask coronagraph holds the ability to detect exoplanets very close to their parent star. We report a new kind of phase mask that performs the contrast ratio of more than the tenth power of 10 for a circular aperture with shades of a secondary mirror and spiders. The phase distribution of the phase mask is numerically obtained by making the leaked light distribute outside the transparent part of the pupil. We applied the hybrid input-output algorithm, one of phase retrieval methods, to find the phase distribution of the phase mask. We show the characteristics of thus obtained phase mask.Conference Title : Techniques and Instrumentation for Detection of Exoplanets VIIConference Chair : Stuart ShaklanPlace : San Diego, California, United StatesDate : August 09, 201

    Galaxy Morphologies Revealed with Subaru HSC and Super-Resolution Techniques II: Environmental Dependence of Galaxy Mergers at z~2-5

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    We super-resolve the seeing-limited Subaru Hyper Suprime-Cam (HSC) images for 32,187 galaxies at z~2-5 in three techniques, namely, the classical Richardson-Lucy (RL) point spread function (PSF) deconvolution, sparse modeling, and generative adversarial networks to investigate the environmental dependence of galaxy mergers. These three techniques generate overall similar high spatial resolution images but with some slight differences in galaxy structures, for example, more residual noises are seen in the classical RL PSF deconvolution. To alleviate disadvantages of each technique, we create combined images by averaging over the three types of super-resolution images, which result in galaxy sub-structures resembling those seen in the Hubble Space Telescope images. Using the combined super-resolution images, we measure the relative galaxy major merger fraction corrected for the chance projection effect, f_merg, for galaxies in the ~300 deg^2-area data of the HSC Strategic Survey Program and the CFHT Large Area U-band Survey. Our f_merg measurements at z~3 validate previous findings showing that f_merg is higher in regions with a higher galaxy overdensity delta at z~2-3. Thanks to the large galaxy sample, we identify a nearly linear increase in f_merg with increasing delta at z~4-5, providing the highest-z observational evidence that galaxy mergers are related to delta. In addition to our f_merg measurements, we find that the galaxy merger fractions in the literature also broadly align with the linear f_merg-delta relation across a wide redshift range of z~2-5. This alignment suggests that the linear f_merg-delta relation can serve as a valuable tool for quantitatively estimating the contributions of galaxy mergers to various environmental dependences. This super-resolution analysis can be readily applied to datasets from wide field-of-view space telescopes such as Euclid and Roman.Comment: 29 pages, 13 figures, 6 tables. Submitted to PASJ. Comments welcom

    Application of double stapling technique after anterior resection for rectal cancer

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    Double stapling technique (DST) were applied in 22 cases who underwent low and high anterior resection of the rectum. Postoperative complications were encounted in six, three were mild strictures and the other three were minor leakages. All were not severe, demonstrating no correlation to the conditions of the anastomosis and subsided by conservative therapy in a short period. Anastomotic leakage occurred in three but these were based on technical problems and it is possible to avoid with careful surgical management. In conclusion, DST is of great benefit for the treatment of carcinoma of the rectum to reduce the consuming operation time and to lessen the risk of bacteriological and oncological contaminations

    A Functional SNP in BNC2 Is Associated with Adolescent Idiopathic Scoliosis

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    Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity. We previously conducted a genome-wide association study (GWAS) and detected two loci associated with AIS. To identify additional loci, we extended our GWAS by increasing the number of cohorts (2,109 affected subjects and 11,140 control subjects in total) and conducting a whole-genome imputation. Through the extended GWAS and replication studies using independent Japanese and Chinese populations, we identified a susceptibility locus on chromosome 9p22.2 (p = 2.46 × 10−13; odds ratio = 1.21). The most significantly associated SNPs were in intron 3 of BNC2, which encodes a zinc finger transcription factor, basonuclin-2. Expression quantitative trait loci data suggested that the associated SNPs have the potential to regulate the BNC2 transcriptional activity and that the susceptibility alleles increase BNC2 expression. We identified a functional SNP, rs10738445 in BNC2, whose susceptibility allele showed both higher binding to a transcription factor, YY1 (yin and yang 1), and higher BNC2 enhancer activity than the non-susceptibility allele. BNC2 overexpression produced body curvature in developing zebrafish in a gene-dosage-dependent manner. Our results suggest that increased BNC2 expression is implicated in the etiology of AIS

    Hot electron and ion spectra on blow-off plasma free target in GXII-LFEX direct fast ignition experiment

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    Polystyrene deuteride shell targets with two holes were imploded by the Gekko XII laser and additionally heated by the LFEX laser in a direct fast ignition experiment. In general, when an ultra-intense laser is injected into a blow-off plasma created by the imploding laser, electrons are generated far from the target core and the energies of electrons increase because the electron acceleration distance has been extended. The blow-off plasma moves not only to the vertical direction but to the lateral direction against the target surface. In a shell target with holes, a lower effective electron temperature can be realized by reducing the inflow of the implosion plasma onto the LFEX path, and high coupling efficiency can be expected. The energies of hot electrons and ions absorbed into the target core were calculated from the energy spectra using three electron energy spectrometers and a neutron time-of-flight measurement system, Mandala. The ions have a large contribution of 74% (electron heating of 4.9 J and ion heating of 14.1 J) to target heating in direct fast ignition
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