180 research outputs found
Flow Simulation of Suspension Bridge Cable Based on Lattice-Boltzmann Method
Suspension bridge is a kind of bridge which uses cables as the main bearing structure. Suspension bridge has the characteristics of saving materials and weak stiffness. With the increase of the span of suspension bridge, wind induced vibration has resulted in injury of several suspension bridges, which leads to a significant loss. Thus, it is imperative to study the wind vibration mechanism of cables. As for this problem, this paper based on motion theory of mesoscopic particles performs flow simulation of cables by LBM which is different from traditional computing method of fluid mechanics. By calculating the distribution function of the distribution on the grid of uniform flow field, the macroscopic motion law of the flow field around cables can be obtained, which can provide reference for wind resistant design of suspension
LSGNN: Towards General Graph Neural Network in Node Classification by Local Similarity
Heterophily has been considered as an issue that hurts the performance of
Graph Neural Networks (GNNs). To address this issue, some existing work uses a
graph-level weighted fusion of the information of multi-hop neighbors to
include more nodes with homophily. However, the heterophily might differ among
nodes, which requires to consider the local topology. Motivated by it, we
propose to use the local similarity (LocalSim) to learn node-level weighted
fusion, which can also serve as a plug-and-play module. For better fusion, we
propose a novel and efficient Initial Residual Difference Connection (IRDC) to
extract more informative multi-hop information. Moreover, we provide
theoretical analysis on the effectiveness of LocalSim representing node
homophily on synthetic graphs. Extensive evaluations over real benchmark
datasets show that our proposed method, namely Local Similarity Graph Neural
Network (LSGNN), can offer comparable or superior state-of-the-art performance
on both homophilic and heterophilic graphs. Meanwhile, the plug-and-play model
can significantly boost the performance of existing GNNs. Our code is provided
at https://github.com/draym28/LSGNN.Comment: The first two authors contributed equally to this work; IJCAI2
Hydrothermal Preparation of Visible-Light-Driven N-Br-Codoped TiO
Using a facile hydrothermal method, N-Br-codoped TiO2 photocatalyst that had intense absorption in visible region was prepared at low temperature (100°C), through a direct reaction between nanocrystalline anatase TiO2 solution and cetyltrimethylammonium bromide (CTAB). The results of X-ray photoelectron spectroscopy (XPS) showed the existence of N-Ti-N, O-Ti-N-R, Ti3+ (attribute to the doped Br atoms by charge compensation), and TiOxNy species, indicating the successful codoping of N and Br atoms, which were substituted for lattice oxygen without any influence on the crystalline phase of TiO2. In contrast to the N-doped sample, the N-Br-codoped TiO2 photocatalyst could more readily photodegrade methylene blue (MB) under visible-light irradiation. The visible-light catalytic activity of thus-prepared photocatalyst resulted from the synergetic effect of the doped nitrogen and bromine, which not only gave high absorbance in the visible-light range, but also reduced electron-hole recombination rate
Multiferroic Magnon Spin-Torque Based Reconfigurable Logic-In-Memory
Magnons, bosonic quasiparticles carrying angular momentum, can flow through
insulators for information transmission with minimal power dissipation.
However, it remains challenging to develop a magnon-based logic due to the lack
of efficient electrical manipulation of magnon transport. Here we present a
magnon logic-in-memory device in a spin-source/multiferroic/ferromagnet
structure, where multiferroic magnon modes can be electrically excited and
controlled. In this device, magnon information is encoded to ferromagnetic bits
by the magnon-mediated spin torque. We show that the ferroelectric polarization
can electrically modulate the magnon spin-torque by controlling the
non-collinear antiferromagnetic structure in multiferroic bismuth ferrite thin
films with coupled antiferromagnetic and ferroelectric orders. By manipulating
the two coupled non-volatile state variables (ferroelectric polarization and
magnetization), we further demonstrate reconfigurable logic-in-memory
operations in a single device. Our findings highlight the potential of
multiferroics for controlling magnon information transport and offer a pathway
towards room-temperature voltage-controlled, low-power, scalable magnonics for
in-memory computing
A Comprehensive X-ray Report on AT2019wey
The Galactic low-mass X-ray binary AT2019wey (ATLAS19bcxp, SRGA J043520.9+552226, SRGE J043523.3+552234, ZTF19acwrvzk) was discovered as a new optical transient in Dec 2019, and independently as an X-ray transient in Mar 2020. In this paper, we present comprehensive NICER, NuSTAR, Chandra, Swift, and MAXI observations of AT2019wey from ~1 year prior to the discovery to the end of September 2020. AT2019wey appeared as a ~1 mCrab source and stayed at this flux density for several months, displaying a hard X-ray spectrum that can be modeled as a power-law with photon index Gamma~1.8. In June 2020 it started to brighten, and reached ~20 mCrab in ~2 months. The inclination of this system can be constrained to i≾30 deg by modeling the reflection spectrum. Starting from late-August (~59082 MJD), AT2019wey entered into the hard-intermediate state (HIMS), and underwent a few week-long timescale outbursts, where the brightening in soft X-rays is correlated with the enhancement of a thermal component. Low-frequency quasi-periodic oscillation (QPO) was observed in the HIMS. We detect no pulsation and in timing analysis of the NICER and NuSTAR data. The X-ray states and power spectra of AT2019wey are discussed against the landscape of low-mass X-ray binaries
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