91 research outputs found
Graph Learning of Multifaceted Motivations for Online Engagement Prediction in Counter-party Social Networks
Social media has emerged as an essential venue to invigorate online political engagement. However, political engagement is multifaceted and impacted by both individuals\u27 self-motivation and social influence from peers and remains challenging to model in a counter-party network. Therefore, we propose a counter-party graph representation learning model to study individuals\u27 intrinsic and extrinsic motivations for online political engagement. Firstly, we capture users\u27 intrinsic political interests providing self-motivation from a user-topic network. Then, we encode how users cast influence on others from the inner-/counter-party through a user-user network. With the learned embedding of intrinsic and extrinsic motivations, we model the interactions between these two facets and utilize the dependency by deep sequential model decoding. Finally, extensive experiments using Twitter data related to the 2020 U.S. presidential election and the 2019 HK protests validate the model\u27s predictive power. This study has implications for online political engagement, political participation, and political polarization
Unconventional Flatband Line States in Photonic Lieb Lattices
Flatband systems typically host "compact localized states"(CLS) due to
destructive interference and macroscopic degeneracy of Bloch wave functions
associated with a dispersionless energy band. Using a photonic Lieb
lattice(LL), we show that conventional localized flatband states are inherently
incomplete, with the missing modes manifested as extended line states which
form non-contractible loops winding around the entire lattice. Experimentally,
we develop a continuous-wave laser writing technique to establish a
finite-sized photonic LL with specially-tailored boundaries, thereby directly
observe the unusually extended flatband line states.Such unconventional line
states cannot be expressed as a linear combination of the previously observed
CLS but rather arise from the nontrivial real-space topology.The robustness of
the line states to imperfect excitation conditions is discussed, and their
potential applications are illustrated
Gentamicin coating of nanotubular anodized titanium implant reduces implant-related osteomyelitis and enhances bone biocompatibility in rabbits
Wearable grain silo working environment sensing and safety alarm system
A set of wearable granary working environment sensing and security alarm system is developed to ensure the safety of granary staff. The gas sensor, piezoelectric ceramic chip, infrared transmitting and receiving tube and photosensitive resistance are used as the core components of each circuit module to collect the gas concentration signal, human respiration intensity signal, pulse intensity signal and light signal in the granary. AD0809 module chip is used to convert analog data into digital data and send it to MCU for information processing to make alarm judgment. At the same time, PTR2000 module is used to transmit the sensor data to the upper computer. The upper computer determines whether to alarm through data comparison, and transmits the alarm signal to the mobile phone through Wi-Fi in real time. Each module cooperates with each other, information real-time transmission to complete the detection of granary environment and danger alarm. The test results show that the system can meet the safety operation requirements of large and medium-sized state-owned grain depot
Robust mode-locking in a hybrid ultrafast laser based on nonlinear multimodal interference
We experimentally demonstrate the realization of a
half-polarization-maintaining (half-PM) fiber laser, in which mode-locking is
provided by a reflective multimode-interference saturable absorber (SA). In the
specially designed SA, linearly polarized light is coupled into a 15-cm-long
graded-index multimode fiber (GIMF) through the PM fiber, and then reflected
back to the PM structure through a mirror pigtailed with a single-mode fiber
(SMF). The modulation depth and saturation peak power are measured to be 1.5%
and 0.6 W, respectively. The proposed SA device is incorporated into a novel
half-PM erbium-doped fiber oscillator, which generates soliton pulses with 409
fs temporal duration at a 33.3 MHz repetition rate. The proposed fiber laser is
compared with a conventional non-PM fiber laser mode-locked by nonlinear
polarization evolution (NPE) in terms of optical properties such as spectral
bandwidth, pulse duration, and stability performance. Short- and long-time
stability tests and superior noise performance corroborate robust mode-locking
in this setup.Comment: to be published in Optics and Laser Technolog
Ecological vulnerability assessment based on remote sensing ecological index (RSEI): A case of Zhongxian County, Chongqing
The ecological vulnerability evaluation index was established through Normalized Difference Vegetation Index (NDVI), Wetness (WET), Normalized Difference Build-up and Soil Index (NDBSI) and Land Surface Temperature (LST) indicators, comprehensively evaluate the ecological vulnerability of Zhongxian County of Chongqing in 2002, 2009, and 2016 by Principal Components Analysis (PCA), and analyze its spatio-temporal evolution. The vulnerability areas of five levels were calculated respectively, and the overall index of ecological vulnerability was also calculated. The index of remote sensing ecological index (RSEI) and Normalized Difference Vegetation Index decreased first and then increased; the Wetness index showed an upward trend; the Normalized Difference Build-up and Soil Index index increased first and then decreased; and the Land Surface Temperature index decreased. The ecological vulnerability body index (EVBI) shows a downward trend, and the incremental changes are mainly concentrated in the negligible vulnerability areas and light vulnerability area, while the medium vulnerability, strong vulnerability and extreme vulnerability area generally show a downward trend. Furthermore, the new increment of ecological vulnerability grade area concentrates on negligible vulnerability area and light vulnerability area from 2002 to 2016. In general, the ecological vulnerability gradually shifts to low vulnerability, and the ecological environment tends to develop healthily
Universal momentum-to-real-space mapping of topological singularities
Topological properties of materials, as manifested in the intriguing
phenomena of quantum Hall effect and topological insulators, have attracted
overwhelming transdisciplinary interest in recent years. Topological edge
states, for instance, have been realized in versatile systems including
electromagnetic-waves. Typically, topological properties are revealed in
momentum space, using concepts such as Chern number and Berry phase. Here, we
demonstrate a universal mapping of the topology of Dirac-like cones from
momentum space to real space. We evince the mapping by exciting the cones in
photonic honeycomb (pseudospin-1/2) and Lieb (pseudospin-1) lattices with
vortex beams of topological charge l, optimally aligned for a chosen pseudospin
state s, leading to direct observation of topological charge conversion that
follows the rule of l to l+2s. The mapping is theoretically accounted for all
initial excitation conditions with the pseudospin-orbit interaction and
nontrivial Berry phases. Surprisingly, such a mapping exists even in a deformed
lattice where the total angular momentum is not conserved, unveiling its
topological origin. The universality of the mapping extends beyond the photonic
platform and 2D lattices: equivalent topological conversion occurs for 3D
Dirac-Weyl synthetic magnetic monopoles, which could be realized in ultracold
atomic gases and responsible for mechanism behind the vortex creation in
electron beams traversing a magnetic monopole field
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