427 research outputs found

    Foam Metals High-Temperature Electrical Characteristics’ Investigation

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    In the work presented we have carried out experimental investigations of high- temperature electrophysical properties of foam metals. We have obtained data of foam nickel and foam copper resistivity and temperature coefficients of resistance (TCR) versus their plane deformation degree within the temperature range from 100 to 950 ºС

    Impact of activation cross-section uncertainties on the tritium production in the HFTM specimen cells

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    The prediction of the tritium production is required for handling procedures of samples, safety & maintenance and licensing of the International Fusion Materials Irradiation Facility (IFMIF). A comparison of the evaluated tritium production cross-sections with available experimental data from the EXFOR data base has shown insufficient validation. And significant discrepancies in evaluated cross-section libraries, including lack of tritium production reactions for some important elements, were found. Here, we have addressed an uncertainty analysis to draw conclusions on the reliability of the tritium prediction under the potential impact of activation cross-section uncertainties. We conclude that there is not sufficient experimental validation of the evaluated tritium production cross-sections, especially for iron and sodium. Therefore a dedicated experimental validation program for those elements should be desirable

    <i>In silico</i> identification and expression of protocadherin gene family in <i>Octopus vulgaris</i>

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    Connecting millions of neurons to create a functional neural circuit is a daunting challenge. Vertebrates developed a molecular system at the cell membrane to allow neurons to recognize each other by distinguishing self from non-self through homophilic protocadherin interactions. In mammals, the protocadherin gene family counts about 50 different genes. By hetero-multimerization, protocadherins are capable of generating an impressive number of molecular interfaces. Surprisingly, in the California two-spot octopus, Octopus bimaculoides, an invertebrate belonging to the Phylum Mollusca, over 160 protocadherins (PCDHs) have been identified. Here we briefly discuss the role of PCDHs in neural wiring and conduct a comparative study of the protocadherin gene family in two closely related octopus species, Octopus vulgaris and O. bimaculoides. A first glance at the expression patterns of protocadherins in O. vulgaris is also provided. Finally, we comment on PCDH evolution in the light of invertebrate nervous system plasticity

    Splash formation at the nose of a smoothly curved body in a stream

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    Positron annihilation spectroscopy study of radiation-induced defects in W and Fe irradiated with neutrons with different spectra

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    The paper presents new knowledge on primary defect formation in tungsten (W) and iron (Fe) irradiated by fission and high-energy neutrons at near-room temperature. Using a well-established method of positron-annihilation lifetime-spectroscopy (PALS), it was found that irradiation of W in the fission reactor and by high-energy neutrons from the p(35 MeV)-Be generator leads to the formation of small radiation-induced vacancy clusters with comparable mean size. In the case of Fe, smaller mean size of primary radiation-induced vacancy clusters was measured after irradiation with fission neutrons compared to irradiation with high-energy neutrons from the p(35 MeV)-Be generator. It was found that one of the reasons of the formation of the larger size of the defects with lower density in Fe is lower flux in the case of irradiation with high-energy neutrons from the p(35 MeV)-Be source. The second reason is enhanced defect agglomeration and recombination within the energetic displacement cascade at high energy primary knock-on-atoms (PKAs). This is consistent with the concept of the athermal recombination corrected (arc-dpa) model, although the measured dpa cross-section of both fission neutrons and wide-spectrum high-energy neutrons in W is between the conventional Norgett–Robinson–Torrens (NRT-dpa) and arc-dpa predictions. This means that the physics of the primary radiation effects in materials is still not fully known and requires further study through a combination of modeling and experimental efforts. The present data serve as a basis for the development of an improved concept of the displacement process

    Metal enhanced luminescence of cerium oxide (IV) hollow sub-microspheres with au, aupd and pd nanoparticles

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    This work reports an analysis of the luminescent properties of Cerium oxide (IV) hollow sub-microspheres (CeO2-HS) as well as the effect of the presence of Au, AuPd and Pd NPs over the mentioned properties. CeO2-HS were synthesized via hydrothermal method, then the CeO2-HS were impregnated with the metal precursors and by a reduction process the metal nanoparticles (NPs) were obtained. CeO2-HS were characterized by XRD, Raman, UVVis and TEM. The CeO2-HS with metal NPs deposited on them were analyzed using UV-Vis and TEM. All samples luminescent excitation and emission spectra were recorded. It was observed that the presence of metal NPs dramatically increases the emission intensity compared to the CeO2-HS without metal NPs. Finally, it was also observed a clear slight but evident displacement of the main emission peak between samples with and without metal NPshttp://laccei.org/LACCEI2021-VirtualEdition/meta/FP487.htm

    The survey and reference assisted assembly of the Octopus vulgaris genome

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    The common octopus, Octopus vulgaris, is an active marine predator known for the richness and plasticity of its behavioral repertoire, and remarkable learning and memory capabilities. Octopus and other coleoid cephalopods, cuttlefish and squid, possess the largest nervous system among invertebrates, both for cell counts and body to brain size. O. vulgaris has been at the center of a long-tradition of research into diverse aspects of its biology. To leverage research in this iconic species, we generated 270\u2009Gb of genomic sequencing data, complementing those available for the only other sequenced congeneric octopus, Octopus bimaculoides. We show that both genomes are similar in size, but display different levels of heterozygosity and repeats. Our data give a first quantitative glimpse into the rate of coding and non-coding regions and support the view that hundreds of novel genes may have arisen independently despite the close phylogenetic distance. We furthermore describe a reference-guided assembly and an open genomic resource (CephRes-gdatabase), opening new avenues in the study of genomic novelties in cephalopods and their biology
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