208 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
Evidence for Stream Collision and Disk Formation in Tidal Disruption Events
When a star passes through the tidal disruption radius of a massive black
hole (BH), it can be torn apart by the tidal force of the BH, known as the
Tidal Disruption Event (TDE). Since the UV/optical emitting region inferred
from the blackbody radius is significantly larger than the circularization
radius predicted by the classical TDE theory, two competing models, stream
collision and envelope reprocessing, were proposed to explain the unexpectedly
large UV/optical emitting size. Here, we investigate the variability behaviors
(cross-correlation and time delay) of three representative TDEs with continuum
reverberation mapping. Our results demonstrate that TDE behavior is clearly
inconsistent with the envelope reprocessing scenario. In contrast, the picture
of the stream collision, together with the late-time formed accretion disk, can
explain heterogeneous observations. This provides compelling evidence that the
UV/optical emission originates from stream collisions during the early-stage of
TDE evolution and gradually transitions to being dominated by accretion disk
with detectable X-ray emission in a late stage. After fading back to a
quiescent state, recurrent flares may be observed in some occasions, such as
partial TDEs.Comment: 56 pages, 21 figures, 5 tables. Submitted, comments welcome
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
Interactions between halotolerant nitrogen-fixing bacteria and arbuscular mycorrhizal fungi under saline stress
Background and aimsSoil salinity negatively affects crop development. Halotolerant nitrogen-fixing bacteria (HNFB) and arbuscular mycorrhizal fungi (AMF) are essential microorganisms that enhance crop nutrient availability and salt tolerance in saline soils. Studying the impact of HNFB on AMF communities and using HNFB in biofertilizers can help in selecting the optimal HNFB-AMF combinations to improve crop productivity in saline soils.MethodsWe established three experimental groups comprising apple plants treated with low-nitrogen (0 mg N/kg, N0), normal-nitrogen (200 mg N/kg, N1), and high-nitrogen (300 mg N/kg, N2) fertilizer under salt stress without bacteria (CK, with the addition of 1,500 mL sterile water +2 g sterile diatomite), or with bacteria [BIO, with the addition of 1,500 mL sterile water +2 g mixed bacterial preparation (including Bacillus subtilis HG-15 and Bacillus velezensis JC-K3)].ResultsHNFB inoculation significantly increased microbial biomass and the relative abundance of beta-glucosidase-related genes in the rhizosphere soil under identical nitrogen application levels (p < 0.05). High-nitrogen treatment significantly reduced AMF diversity and the relative abundance of beta-glucosidase, acid phosphatase, and urea-related genes. A two-way analysis of variance showed that combined nitrogen application and HNFB treatment could significantly affect soil physicochemical properties and rhizosphere AMF abundance (p < 0.05). Specifically, HNFB application resulted in a significantly higher relative abundance of Glomus-MO-G17-VTX00114 compared to that in the CK group at equal nitrogen levels.ConclusionThe impact of HNFB on the AMF community in apple rhizospheres is influenced by soil nitrogen levels. The study reveals how varying nitrogen levels mediate the relationship between exogenous HNFB, soil properties, and rhizosphere microbes
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