357 research outputs found
5G Ultra-dense networks with non-uniform Distributed Users
User distribution in ultra-dense networks (UDNs) plays a crucial role in
affecting the performance of UDNs due to the essential coupling between the
traffic and the service provided by the networks. Existing studies are mostly
based on the assumption that users are uniformly distributed in space. The
non-uniform user distribution has not been widely considered despite that it is
much closer to the real scenario. In this paper, Radiation and Absorbing model
(R&A model) is first adopted to analyze the impact of the non-uniformly
distributed users on the performance of 5G UDNs. Based on the R&A model and
queueing network theory, the stationary user density in each hot area is
investigated. Furthermore, the coverage probability, network throughput and
energy efficiency are derived based on the proposed theoretical model. Compared
with the uniformly distributed assumption, it is shown that non-uniform user
distribution has a significant impact on the performance of UDNs.Comment: 14 pages, 10 figure
A study on compressive anisotropy and nonassociated flow plasticity of the AZ31 Magnesium Alloy in hot rolling
Effect of anisotropy in compression is studied on hot rolling of AZ31 magnesium alloy with a three-dimensional constitutive model based on the quadratic Hill48 yield criterion and nonassociated flow rule (non-AFR). The constitutive model is characterized by compressive tests of AZ31 billets since plastic deformations of materials are mostly caused by compression during rolling processes. The characterized plasticity model is implemented into ABAQUS/Explicit as a user-defined material subroutine (VUMAT) based on semi-implicit backward Euler\u27s method. The subroutine is employed to simulate square-bar rolling processes. The simulation results are compared with rolled specimens and those predicted by the von Mises and the Hill48 yield function under AFR. Moreover, strip rolling is also simulated for AZ31 with the Hill48 yield function under non-AFR. The strip rolling simulation demonstrates that the lateral spread generated by the non-AFR model is in good agreement with experimental data. These comparisons between simulation and experiments validate that the proposed Hill48 yield function under non-AFR provides satisfactory description of plastic deformation behavior in hot rolling for AZ31 alloys in case that the anisotropic parameters in the Hill48 yield function and the non-associated flow rule are calibrated by the compressive experimental results
Higher-order Oscillatory Planar Hall Effect in Topological Kagome Metal
Exploration of exotic transport behavior for quantum materials is of great
interest and importance for revealing exotic orders to bring new physics. In
this Letter, we report the observation of exotic prominent planar Hall effect
(PHE) and planar anisotropic magnetoresistivity (PAMR) in strange kagome metal
KVSb. The PHE and PAMR, which are driven by an in-plane magnetic field
and display sharp difference from other Hall effects driven by an out-of-plane
magnetic field or magnetization, exhibit exotic higher-order oscillations in
sharp contrast to those following empirical rule only allowing twofold
symmetrical oscillations. These higher-order oscillations exhibit strong field
and temperature dependence and vanish around charge density wave (CDW)
transition. The unique transport properties suggest a significant interplay of
the lattice, magnetic and electronic structure in KVSb. This interplay
can couple the hidden anisotropy and transport electrons leading to the novel
PHE and PAMR in contrast to other materials
On-chip light-scattering enhancement enables high performance single-particle tracking under conventional bright-field microscope
Scattering-based single-particle tracking (S-SPT) has opened new avenues for
highly sensitive label-free detection and characterization of nanoscopic
objects, making it particularly attractive for various analytical applications.
However, a long-standing issue hindering its widespread applicability is its
high technical demands on optical systems. The most promising solution entails
implementing on-chip light-scattering enhancement, but the existing
field-enhancement technology fails as their highly localized field is
insufficient to cover the three-dimensional trajectory of particles within the
interrogation time. Here, we present a straightforward and robust on-chip
microlens-based strategy for light-scattering enhancement, providing an
enhancement range ten times greater than that of near-field optical techniques.
These properties are attributed to the increased long-range optical fields and
complex composite interactions between two closely spaced structures. Thanks to
this strategy, we demonstrate that high-performance S-SPT can be achieved, for
the first time, under a conventional bright-field microscope with illumination
powers over 1,000 times lower than typically required. This significantly
reduces the technical demands of S-SPT, representing a significant step forward
in facilitating its practical application in biophotonics, biosensors,
diagnostics, and other fields.Comment: 29 pages,4 figure
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