2,685 research outputs found

    First-principles study, fabrication and characterization of (Zr0.25Nb0.25Ti0.25V0.25)C high-entropy ceramic

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    The formation possibility of a new (Zr0.25Nb0.25Ti0.25V0.25)C high-entropy ceramic (ZHC-1) was first analyzed by the first-principles calculations and thermodynamical analysis and then it was successfully fabricated by hot pressing sintering technique. The first-principles calculation results showed that the mixing enthalpy of ZHC-1 was 5.526 kJ/mol and the mixing entropy of ZHC-1 was in the range of 0.693R-1.040R. The thermodynamical analysis results showed that ZHC-1 was thermodynamically stable above 959 K owing to its negative mixing Gibbs free energy. The experimental results showed that the as-prepared ZHC-1 (95.1% relative density) possessed a single rock-salt crystal structure, some interesting nanoplate-like structures and high compositional uniformity from nanoscale to microscale. By taking advantage of these unique features, compared with the initial metal carbides (ZrC, NbC, TiC and VC), it showed a relatively low thermal conductivity of 15.3 + - 0.3 W/(m.K) at room temperature, which was due to the presence of solid solution effects, nanoplates and porosity. Meanwhile, it exhibited the relatively high nanohardness of 30.3 + - 0.7 GPa and elastic modulus of 460.4 + - 19.2 GPa and the higher fracture toughness of 4.7 + - 0.5 MPa.m1/2, which were attributed to the solid solution strengthening mechanism and nanoplate pullout and microcrack deflection toughening mechanism.Comment: 49 pages,6 figures, 4 table

    The impact of employee’s perception of organizational climate on their technology acceptance toward e-learning in South Korea

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    To better understand the relationship between e-learning integration and organizational factors in South Korea, this study explored the influence of employees’ perceptions of organizational climate on their technology acceptances toward e-learning in the workplace of South Korea. Employees’ perceptions of organizational climate was evaluated using Litwin & Stringer’s Organizational Climate Questionnaire (LSOCQ) and employees’ technology acceptance toward e-learning was measured by the Unified Theory of Acceptance and Use of Technology (UTAUT). A canonical correlation suggested that employees’ perceived organizational climate can influence their acceptance levels toward e-learning, which implies the importance of addressing organizational issues while integrating e-learning into workplaces in South Korea

    Accelerating Antimicrobial Peptide Discovery with Latent Structure

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    Antimicrobial peptides (AMPs) are promising therapeutic approaches against drug-resistant pathogens. Recently, deep generative models are used to discover new AMPs. However, previous studies mainly focus on peptide sequence attributes and do not consider crucial structure information. In this paper, we propose a latent sequence-structure model for designing AMPs (LSSAMP). LSSAMP exploits multi-scale vector quantization in the latent space to represent secondary structures (e.g. alpha helix and beta sheet). By sampling in the latent space, LSSAMP can simultaneously generate peptides with ideal sequence attributes and secondary structures. Experimental results show that the peptides generated by LSSAMP have a high probability of antimicrobial activity. Our wet laboratory experiments verified that two of the 21 candidates exhibit strong antimicrobial activity. The code is released at https://github.com/dqwang122/LSSAMP.Comment: KDD 202

    4-(Anthracen-9-yl)-2-phenyl-6-(pyridin-2-yl)pyridine

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    In the title compound, C30H20N2, the anthracene ring system is approximately planar [maximum deviation = 0.035 (2) Å] and is nearly perpendicular to the central pyridine ring, making a dihedral angle of 75.73 (7)°. The terminal pyridine ring and the phenyl ring are oriented at dihedral angles of 8.11 (10) and 13.22 (10)°, respectively, to the central pyridine ring

    Poly[(μ4-tetra­zole-1-acetato-κ4 N 3:N 4:O:O′)silver(I)]

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    In the title complex, [Ag(C3H3N4O2)]n, the AgI atom is four-coordinated in a slightly distorted tetra­hedral coordination geometry by two N atoms from two tetra­zole-1-acetate (tza) ligands and two O atoms from the other two tza ligands. The tza ligand bridges two Ag atoms through the carboxyl­ate O atoms and simultaneously binds to the other two Ag atoms through the tetra­zole N atoms, forming a two-dimensional network parallel to (100)

    Physiological and Metabolomic Alterations in Macrocystis pyrifera upon Exposure to Chromium(VI)

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    1593-1599In order to comprehensively characterize the effects of chromium (VI) on physiological and metabonomic performance of Macrocystis pyrifera, the sporophytes were exposed to 2 mg L-1 potassium dichromate for 3 days. M. pyrifera sporophytes showed decreased pigment content and Chla fuloresecnece parameters with the accumulation of Cr(VI). The carbon content was clearly increased, while the content of nitrogen, hydrogen and sulfur were little changed. Moreover, an untargeted metabolomic analysis was carried out in order to investigate the metabolic effects and to obtain a comprehensive profiling of induced metabolites during Cr stress. Absolute quantification of 14 different metabolites was obtained through GC-MS methods. The principal component analysis showed a clear separation between control and Cr treated samples. Some pathways including carbon fixation, sulfur metabolism, taurine and hypotaurine metabolism were affected by Cr (VI) stress. These findings provided valuable information to elucidate the mechanism of M. pyrifera upon Cr (VI) stress

    Suppression of the multiplicity fluctuations in particle correlations

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    Multiplicity fluctuations play a crucial role in relativistic heavy-ion collisions. In this work, we explore how the multiplicity fluctuations can be effectively suppressed in the measurement of particle correlations. In particular, through proper normalization, particle correlations can be evaluated in a manner irrelevant to multiplicity. When the multiplicity fluctuations are adequately extracted, Monte Carlo simulations show that the remaining correlations possess distinct features buried in the otherwise overwhelming fluctuations. Moreover, we argue that such a normalization scheme naturally agrees with the multi-particle correlator, which can be evaluated using the Q-vectors. The implications of the present study in the data analysis are also addressed.Comment: 15 pages, 3 figure
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