1,467 research outputs found

    Timelike Entanglement Entropy from Rindler Method

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    For a Lorentzian invariant theory, the entanglement entropy should be a function of the dependence of domain of the subregion under consideration. More precisely, it should be a function of the dependence of domain and the appropriate cut-off. In this paper, we define the concept of cut-off to make it applicable to timelike regions and assume that the usual entanglement entropy formula also applies to timelike intervals. Using the Rindler method, the timelike entanglement entropy can be regarded as the thermal entropy of the CFT after the Rindler transformation plus a constant icπ/6ic\pi/6 with cc the central charge of the CFT. The gravitational dual of the timelike entanglement entropy is finally presented following this method.Comment: 14 pages, 3 figure

    1,5-Bis[1-(2,4-dihy­droxy­phen­yl)ethyl­idene]carbonohydrazide dimethyl­formamide disolvate

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    In the title compound, C17H18N4O5·2C3H7NO, two solvent mol­ecules are linked to the main mol­ecule via N—H⋯O and O—H⋯O hydrogen bonds, forming a hydrogen-bonded trimer. Intra­molecular O—H⋯N hydrogen bonds influence the mol­ecular conformation of the main mol­ecule, and the two benzene rings form a dihedral angle of 10.55 (18)°. In the crystal, inter­molecular O—H⋯O hydrogen bonds link hydrogen-bonded trimers into ribbons extending along the b axis

    PosterLayout: A New Benchmark and Approach for Content-aware Visual-Textual Presentation Layout

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    Content-aware visual-textual presentation layout aims at arranging spatial space on the given canvas for pre-defined elements, including text, logo, and underlay, which is a key to automatic template-free creative graphic design. In practical applications, e.g., poster designs, the canvas is originally non-empty, and both inter-element relationships as well as inter-layer relationships should be concerned when generating a proper layout. A few recent works deal with them simultaneously, but they still suffer from poor graphic performance, such as a lack of layout variety or spatial non-alignment. Since content-aware visual-textual presentation layout is a novel task, we first construct a new dataset named PosterLayout, which consists of 9,974 poster-layout pairs and 905 images, i.e., non-empty canvases. It is more challenging and useful for greater layout variety, domain diversity, and content diversity. Then, we propose design sequence formation (DSF) that reorganizes elements in layouts to imitate the design processes of human designers, and a novel CNN-LSTM-based conditional generative adversarial network (GAN) is presented to generate proper layouts. Specifically, the discriminator is design-sequence-aware and will supervise the "design" process of the generator. Experimental results verify the usefulness of the new benchmark and the effectiveness of the proposed approach, which achieves the best performance by generating suitable layouts for diverse canvases.Comment: Accepted to CVPR 2023. Dataset and code are available at https://github.com/PKU-ICST-MIPL/PosterLayout-CVPR202

    Penetration of hydroxyl radicals in the aqueous phase surrounding a cavitation bubble

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    In the sonochemical degradation of nonvolatile compounds, the free radicals must be delivered into the aqueous solution from the cavitation bubble to initiate reduction–oxidation reactions. The penetration depth in the liquid becomes an important parameter that influences the radical delivery efficiency and eventual treatment performance. However, the transport of radicals in the liquid phase is not well understood yet. In this paper, we focus on the most reactive OH radical and numerically simulate its penetration behavior. This is realized by solving the coupled equations of bubble dynamics, intracavity chemistry, and radical dispersion in the aqueous phase. The results present both the local and global penetration patterns for the OH radicals. By performing simulations over a wide range of acoustic parameters, we find an undesirable phenomenon that the penetration can be adversely suppressed when strengthening the radical production. A mechanistic analysis attributes this to the excessively vigorous recombination reactions associated with high radical concentrations near the bubble interface. In this circumstance, the radicals are massively consumed and converted into molecular species before they can appreciably diffuse away. Our study sheds light on the interplay between radical production inside the bubble and dispersion in the outside liquid. The derived conclusions provide guides for sonochemical applications from a new perspective

    Effect of sidewall on the flame extension characteristics beneath a ceiling induced by carriage fire in a channel

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    Laboratory tests were firstly conducted in a reduced scale channel to investigate the conditions for flame ejections when the carriage was at the centre of the channel. The ejected flames were recorded by two cameras and the temperature inside the enclosure and on the ceiling were measured. The lower critical heat release rate (HRR) which would result in intermittent flame ejection and upper critical HRR which would lead to continuous external flame were analysed with regards to their variations with the ventilation factor. Correlations for the longitudinal and transverse flame extension lengths and flame extension area beneath the ceiling were proposed. Subsequently further experimental investigations were conducted to study the effect of sidewall constraint on flame extension by changing the position of the carriage along the transverse direction to vary the distance between the sidewall and the carriage opening, which was also systematically varied. With the decrease of the sidewall-to-opening distance, the longitudinal flame extension length was found to increase whereas the transverse flame extension length decreased. The changes are most significant when sidewall-to-opening distance was relatively small. These trends are different from those observed in previous wall-attached fires or corner fires in channels, where the flame extension length beneath the ceiling firstly increased with the decrease of sidewall-source distance, and then decreased slightly when the fire source was attached to the wall. New correlations were proposed to account for the effect of sidewall-to-opening distance for longitudinal and transverse flame extension lengths under the ceiling. They captured well the measurements for all the present cases and some published cases not used in their derivation, demonstrating the potential for fire safety engineering applications

    Topological Insulators-Based Magnetic Heterostructure

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    The combination of magnetism and topology in magnetic topological insulators (MTIs) has led to unprecedented advancements of time reversal symmetry-breaking topological quantum physics in the past decade. Compared with the uniform films, the MTI heterostructures provide a better framework to manipulate the spin-orbit coupling and spin properties. In this review, we summarize the fundamental mechanisms related to the physical orders host in (Bi,Sb)2(Te,Se)3-based hybrid systems. Besides, we provide an assessment on the general strategies to enhance the magnetic coupling and spin-orbit torque strength through different structural engineering approaches and effective interfacial interactions. Finally, we offer an outlook of MTI heterostructures-based spintronics applications, particularly in view of their feasibility to achieve room-temperature operation.Comment: 33 pages, 11 figure

    Quantum quenches in a pseudo-Hermitian Chern insulator

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    We propose to uncover the topology of a pseudo-Hermitian Chern insulator by quantum quench dynamics. The Bloch Hamiltonian of the pseudo-Hermitian Chern insulator is defined in the basis of the q-deformed Pauli matrices, which are related to the representation of the deformed algebras. We show the bulk-surface duality of the pseudo-Hermitian phases, then further build a concrete relation between the static band topology and quench dynamics, in terms of the time-averaged spin textures. The results are also generalized into a fully nonequilibrium case where the post quench evolution is governed by a Floquet pseudo-Hermitian Hamiltonian. Furthermore, we propose a possible scheme to realize the seemingly challenging model in a bilayer lattice and detect the dynamics with a double-quench protocol.Comment: 9 pages, 6 figure

    2-{[4-(Dimethyl­amino)­benzyl­idene]amino}­phenyl disulfide

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    In the title mol­ecule, C30H30N4S2, the two benzene rings connected through the disulfide chain form a dihedral angle of 88.7 (1)°, and the two benzene rings in the benzyl­ideneaniline fragments form dihedral angles of 34.0 (1) and 35.4 (1)°. The crystal packing exhibits no significantly short inter­molecular contacts

    A New Regularized Matrix Discriminant Analysis (R-MDA) Enabled Human-Centered EEG Monitoring Systems

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    The wider use of wearable devices for electroencephalogram (EEG) data capturing providesa very useful way for the monitoring and self-management of human health. However, the large volumesof data with high dimensions cause computational complexity in EEG data processing and pose a greatchallenge to the use of wearable EEG devices in healthcare. This paper proposes a new approach to extract thestructural information of EEG data and tackle the curse of dimensionality of the EEG data. A set of methodsfor dimensionality reduction (DR)-like linear discriminant analysis (LDA) and their improved methodshave been developed for EEG processing in the literature. However, the existing LDA-related methodssuffer from the singularity problem or expensive computational cost, and none of existing methods takeinto consideration the structure of the projection matrix, which is crucial for the extraction of the structuralinformation of the EEG data. In this paper, a new method called a regularized matrix discriminant analysis(R-MDA) is proposed for EEG feature representation and DR. In the R-MDA, the EEG data are representedas a data matrix, and projection vectors are reshaped to be a set of projection matrices stacking together. Byreformulating the LDA as a least-square formulation and imposing specified constraint on each projectionmatrix, the new R-MDA has been constructed to effectively reduce EEG dimensions and capturing thestructural information of the EEG data. Experimental results demonstrate that this new R-MDA outperformsthe existing LDA-related methods, including achieving improved accuracy with significant DR of the EEGdata. This offers an effective way to enable wearable EEG devices be applicable in human-centered healthmonitorin

    Ethyl 6-(2-chloro­phen­yl)-4-methyl-1-(3-oxobut­yl)-2-thioxo-1,2,3,6-tetra­hydro­pyrimidine-5-carboxyl­ate

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    In the title mol­ecule, C18H21ClN2O3S, the pyrimidine ring exhibits a half-chair conformation. The ethyl group is disordered between two positions in a ratio 0.74:0.26. In the crystal structure, the mol­ecules are linked into chains along the a axis by N—H⋯O hydrogen bonds
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