An original vision for the structural formation of (Sm,Zr)(Co,Cu,Fe)Z alloys, the compositions of which show promise for manufacturing high-coercivity permanent magnets, is reported. Foundations ...arising from the quantitative analysis of alloy microstructures as the first, coarse, level of heterogeneity are considered. The structure of the alloys, in optical resolutions, is shown to be characterized by three structural phase components, which are denoted as A, B, and C and based on the 1:5, 2:17, and 2:7 phases, respectively. As the chemical composition of alloys changes monotonically, the quantitative relationships of the components A, B, and C vary over wide ranges. In this case, the hysteretic properties of the (Sm,Zr)(Co,Cu,Fe)Z alloys in the high-coercivity state are strictly controlled by the volume fractions of the A and B structural components. Based on quantitative relationships of the A, B, and C structural components for the (R,Zr)(Co,Cu,Fe)Z alloys with R = Gd or Sm, sketches of quasi-ternary sections of the (Co,Cu,Fe)-R-Zr phase diagrams at temperatures of 1160–1190 °C and isopleths for the 2:17–2:7 phase composition range of the (Co,Cu,Fe)–Sm–Zr system were constructed.
This paper is concerned with modeling of anisotropic fracture forming limit diagram considering non-directionality of the equi-biaxial fracture strain. A new anisotropic ductile fracture criterion is ...developed based on the Lou–Huh ductile fracture criterion (Lou et al., 2012). In an attempt to predict the forming severity of advanced high-strength steel (AHSS) sheets, the proposed fracture criterion is converted into a Fracture Forming Limit Diagram (FFLD) and anisotropic fracture locus considering the sheet metal orientation. Tensile tests of the DP980 steel sheet with the thickness of 1.2 mm are conducted using various specimen geometries including pure shear, dog-bone, and flat grooved specimens. With Digital Image Correlation (DIC) method, equivalent plastic strain distribution on the specimen surface is computed until surface crack initiates. The fracture predictability of the proposed fracture criterion is evaluated with the experimental results which cover a wide range of stress states in various loading directions. By comparing fracture strains obtained from the experiments with the ones predicted from the proposed fracture criterion, it is clearly confirmed that the fracture criterion proposed is capable of predicting the equivalent plastic strain at the onset of fracture with great accuracy over a wide range of stress states while keeping non-directionality of the equi-biaxial fracture strain.
Automatic modulation recognition (AMR) is an essential and challenging topic in the development of the cognitive radio (CR), and it is a cornerstone of CR adaptive modulation and demodulation ...capabilities to sense and learn environments and make corresponding adjustments. AMR is essentially a classification problem, and deep learning achieves outstanding performances in various classification tasks. So, this paper proposes a deep learning-based method, combined with two convolutional neural networks (CNNs) trained on different datasets, to achieve higher accuracy AMR. A CNN is trained on samples composed of in-phase and quadrature component signals, otherwise known as in-phase and quadrature samples, to distinguish modulation modes, that are relatively easy to identify. We adopt dropout instead of pooling operation to achieve higher recognition accuracy. A CNN based on constellation diagrams is also designed to recognize modulation modes that are difficult to distinguish in the former CNN, such as 16 quadratic-amplitude modulation (QAM) and 64 QAM, demonstrating the ability to classify QAM signals even in scenarios with a low signal-to-noise ratio.
Class diagram is an important model in object-oriented software development. A class diagram specifies the structure of a system with the system's classes, classes’ attributes and methods, and ...relations among classes. Sometimes class diagrams should be modified in accordance with requirements changes or correction of errors. In such a modification, careless mistakes may lead to include another error in the diagram. In this paper, we propose a method of visualization of the difference between original class diagram and modified one by emphasizing the difference in order to avoid newly produced errors. We illustrate our method with examples.
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In order to study the thermodynamics of high entropy alloys, the evolution of the structure and microstructure of the equimolar CrMnFeCoNi high entropy alloy was investigated during ...processing under varying conditions (cooling rate and annealing duration). For the very first time, a true solid-solution down to the atomic scale was evidenced in an HEA by atom probe tomography. It was shown that this face-centered cubic single-phase solid solution is the high temperature stable state of the equimolar CrMnFeCoNi alloy. By analogy with completely miscible binary alloy, the CrMnFeCoNi HEA can be described by a schematic phase diagram of the CrFeCo–MnNi system consisting of a liquidus and a solidus, with a partition coefficient of 0.74. When the liquid phase is cooled down, dendrites enriched in Co, Cr and Fe are formed and afterward interdendrites enriched in Mn and Ni solidify. The solid solution can be reached either by a fast enough cooling or by annealing the dendritic structure, for example at 1100°C for 1h. A method to optimize the temperature and duration of an annealing of homogenization is proposed.
Unitary circuits subject to repeated projective measurements can undergo an entanglement phase transition (EPT) as a function of the measurement rate. This transition is generally understood in terms ...of a competition between the scrambling effects of unitary dynamics and the disentangling effects of measurements. We find that, surprisingly, EPTs are possible even in the absence of scrambling unitary dynamics, where they are best understood as arising from measurements alone. This finding motivates us to introduce measurement-only models, in which the “scrambling” and “unscrambling” effects driving the EPT are fundamentally intertwined and cannot be attributed to physically distinct processes. These models represent a novel form of an EPT, conceptually distinct from that in hybrid unitary-projective circuits. We explore the entanglement phase diagrams, critical points, and quantum code properties of some of these measurement-only models. We find that the principle driving the EPTs in these models is frustration, or mutual incompatibility, of the measurements. Surprisingly, an entangling (volume-law) phase is the generic outcome when measuring sufficiently long but still local (≳3-body) operators. We identify a class of exceptions to this behavior (“bipartite ensembles”) which cannot sustain an entangling phase but display dual area-law phases, possibly with different kinds of quantum order, separated by self-dual critical points. Finally, we introduce a measure of information spreading in dynamics with measurements and use it to demonstrate the emergence of a statistical light cone, despite the nonlocality inherent to quantum measurements.
Gaia DR2 study of Herbig Ae/Be stars Vioque, M.; Oudmaijer, R. D.; Baines, D. ...
Astronomy and astrophysics (Berlin),
12/2018, Letnik:
620
Journal Article
Recenzirano
Odprti dostop
Aims. We use Gaia Data Release 2 (DR2) to place 252 Herbig Ae/Be stars in the Hertzsprung–Russell diagram and investigate their characteristics and properties. Methods. For all known Herbig Ae/Be ...stars with parallaxes in Gaia DR2, we collected their atmospheric parameters and photometric and extinction values from the literature. To these data we added near-infrared and mid-infrared photometry, and collected Hα emission line properties such as equivalent widths and line profiles, and their binarity status. In addition, we developed a photometric variability indicator from Gaia’s DR2 information. Results. We provide masses, ages, luminosities, distances, photometric variabilities and IR excesses homogeneously derived for the most complete sample of Herbig Ae/Be stars to date. We find that high-mass stars have a much smaller IR excess and have much lower optical variabilities compared to lower-mass stars, with the break at around 7 M⊙. Hα emission is generally correlated with IR excess, with the correlation being stronger for IR emission at wavelengths tracing the hot dust closest to the star. The variability indicator as developed by us shows that ∼25% of all Herbig Ae/Be stars are strongly variable. We observe that the strongly variable objects display doubly peaked Hα line profiles, indicating an edge-on disk. Conclusions. The fraction of strongly variable Herbig Ae stars is close to that found for A-type UX Ori stars. It had been suggested that this variability is in most cases due to asymmetric dusty disk structures seen edge-on. The observation here is in strong support of this hypothesis. Finally, the difference in dust properties occurs at 7 M⊙, while various properties traced at UV/optical wavelengths differ at a lower mass, 3 M⊙. The latter has been linked to different accretion mechanisms at work, whereas the differing IR properties and photometric variabilities are related to different or differently acting (dust-)disk-dispersal mechanisms.
We solve the magnetostriction strains for B20 helimagnets in the skyrmion crystal phase. By taking MnSi as an example, we reproduce its temperature-magnetic field (T-B) phase diagrams within a ...thermodynamic potential incorporating magnetoelastic interactions. The calculation shows that the normal strain 33 undergoes a sudden jump through a conical-skyrmion phase transition at any temperature. The corresponding experimental measurements for MnSi agree quantitatively well with the calculation.
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