1,619 research outputs found

    DRINet for medical image segmentation

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    Convolutional neural networks (CNNs) have revolutionized medical image analysis over the past few years. The UNet architecture is one of the most well-known CNN architectures for semantic segmentation and has achieved remarkable successes in many different medical image segmentation applications. The U-Net architecture consists of standard convolution layers, pooling layers, and upsampling layers. These convolution layers learn representative features of input images and construct segmentations based on the features. However, the features learned by standard convolution layers are not distinctive when the differences among different categories are subtle in terms of intensity, location, shape, and size. In this paper, we propose a novel CNN architecture, called Dense-Res-Inception Net (DRINet), which addresses this challenging problem. The proposed DRINet consists of three blocks, namely a convolutional block with dense connections, a deconvolutional block with residual Inception modules, and an unpooling block. Our proposed architecture outperforms the U-Net in three different challenging applications, namely multi-class segmentation of cerebrospinal fluid (CSF) on brain CT images, multi-organ segmentation on abdominal CT images, multi-class brain tumour segmentation on MR images

    The Mechanism of Formation of Iron Oxide and Oxyhydroxides in Aqueous Solutions at Room Temperature(Chemistry)

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    For a better understanding of the atmospheric rusting of iron and steels, the present work is aimed to explore the mechanism of formation of green rusts, Fe_3O_4, α-FeOOH, β-FeOOH, γ-FeOOH, δ-FeOOH and amorphous ferric oxyhydroxide in aqueous solution at room temperature. The formation processes on which end products are determined are strongly affected by the oxidation rate, pH and the structure and composition of initial and intermediate species of iron. The systematic diagram of formation processes of iron oxide and oxyhydroxides has been presented, in which both dissolved and solid species of iron are included

    ALKALI-RICH FRAGMENTS IN LL-CHONDRITIC BRECCIAS.

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    第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月17日(木) 国立国語研究所 2階講

    Luminosity versus Phase-Space-Density Relation of Galaxies Revisited

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    We reexamined the correlation between the B-T magnitude and the phase-space-density parameter w = (D-2(25) v(o))(-1) of galaxies for the Virgo, the Coma, the Fornax, and the Perseus clusters in an effort to better understand the physical underpinning of the fundamental plane. A tight correlation (B-T = a log w + b) common to different morphological types of galaxies (E, S0, S) was found for the Virgo and the Coma clusters, with a = 1.87 +/- 0.10 and 1.33 +/- 0.11, respectively. An investigation using only E galaxies was made for the four clusters. The results indicated that the empirical linear relation might be common among the Coma, the Fornax, and the Perseus clusters, with the Virgo Cluster showing deviation. This relation, which is another way to project the fundamental plane, has an expression insensitive to the morphology and may be suitable for treating galaxies of different morphological types collectively.ArticleThe Astrophysical Journal. 531:665-675 (2000)journal articl

    Time-of-Flight Pulsed Neutron Diffraction of Pd_<0.8>-Si_<0.2> Amorphous Alloy Using the Electron Linac

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    The structure factor S(Q) of Pd_-Si_ amorphous alloy was measured over wide range of Q (=4π sin θ/λ) up to 40 A^ by time-of-flight neutron diffraction using pulsed epithermal-neutron generated from the Tohoku University electron linac. The S(Q) has definitely shown an oscillation even in range of Q≳25 A^. The 1st peak of the pair distribution function Fourier transformed from the S(Q) has been split into two sub-peaks at the position of 2.42 and 2.81 A. Combining the neutron result with the X-ray result, the 1st sub-peak was verified to correspond to Pd-Si pair and the 2nd sub-peak the mixture of Pd-Pd pair and Pd-Si pair where Pd atom was substituted with Si atom. The average numbers of the nearest neighbour atoms around the Pd atom at origin are 1.7 Si atoms in the 1st sub-peak and 10.7 Pd and 1.5 Si atoms in the 2nd sub-peak. There may be no Si-Si pair with the nearest interatomic distance in the alloy. Such a relation for atom-atom pairs is found in the crystalline Pd_3Si compound, too. The liquid structure of the alloy was also measured and concluded to be essentially close to the amorphous structure except more blurring of peaks

    Formation of Fe(II)_1-Fe(III)_3 Green Complex on Oxidation of Ferrous Ion in Perchloric Acid Solution

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    The interaction between Fe(II)-Fe(III) in strong acidic solution has been investigated by means of electronic and Raman spectra, magnetic susceptibility measurement and chemical analysis of the solution. It was found that the green intermediate complex having an absorption band at 337 nm was formed on oxidation of Fe(H_2O)^_6 in perchloric acid solution. The Fe(II)/Fe(III) ratio in the green complex was a third. The configuration of the complex consisting of Fe(II)-O-Fe(III) oxo-bridges was suggested

    The Advantage of Increased Resolution in the Study of Quasar Absorption Systems

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    We compare a new R = 120,000 spectrum of PG1634+706 (z_QSO = 1.337,m_V = 14.9) obtained with the HDS instrument on Subaru to a R = 45, 000 spectrum obtained previously with HIRES/Keck. In the strong MgII system at z = 0.9902 and the multiple cloud, weak MgII system at z = 1.0414, we find that at the higher resolution, additional components are resolved in a blended profile. We find that two single-cloud weak MgII absorbers were already resolved at R = 45,000, to have b = 2 - 4 km/s. The narrowest line that we measure in the R = 120, 000 spectrum is a component of the Galactic NaI absorption, with b = 0.90+/-0.20 km/s. We discuss expectations of similarly narrow lines in various applications, including studies of DLAs, the MgI phases of strong MgII absorbers, and high velocity clouds. By applying Voigt profile fitting to synthetic lines, we compare the consistency with which line profile parameters can be accurately recovered at R = 45,000 and R = 120,000. We estimate the improvement gained from superhigh resolution in resolving narrowly separated velocity components in absorption profiles. We also explore the influence of isotope line shifts and hyperfine splitting in measurements of line profile parameters, and the spectral resolution needed to identify these effects. Super high resolution spectra of quasars, which will be routinely possible with 20-meter class telescopes, will lead to greater sensitivity for absorption line surveys, and to determination of more accurate physical conditions for cold phases of gas in various environments.Comment: To appear in AJ. Paper with better resolution images available at http://www.astro.psu.edu/users/anand/superhigh.AJ.pd

    Visible and Near-Infrared Spectral Survey of Select HED Meteorite Samples Stored at the National Institute of Polar Research.

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    第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月18日(金) 国立国語研究所 2階講

    Rb-Sr Isotopic Studies Of Antarctic Lherzolitic Shergottite Yamato 984028

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    Yamato 984028 is a Martian meteorite found in the Yamato Mountains of Antarctica. It is classified as a lherzolitic shergottite and petrographically resembles several other lherzolitic shergottites, i.e. ALHA 77005, LEW 88516, Y-793605 and Y-000027/47/97 [e.g. 2-5]. These meteorites have similarly young crystallization ages (152-185 Ma) as enriched basaltic shergottites (157-203 Ma), but have very different ejection ages (approximately 4 Ma vs. approximately 2.5 Ma), thus they came from different martian target crater areas. Lherzolitic shergottites have mg-values approximately 0.70 and represent the most mafic olivine-pyroxene cumulates. Their parental magmas were melts derived probably from the primitive Martian mantle. Here we present Rb-Sr isotopic data for Y-984028 and compare these data with those obtained from other lherzolitic and olivine-phyric basaltic shergottites to better understand the isotopic characteristics of their primitive mantle source regions. Corresponding Sm-Nd analyses for Y-984028 are in progress
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