61 research outputs found
Collective flow and the fluid behavior in p/d/He+Au collisions at GeV
By varying the intrinsic initial geometry, the p/d/He+Au collisions at
the Relativistic Heavy Ion Collider (RHIC) provide a unique opportunity to
understand the collective behavior in the small systems. In this paper, we
employ the hybrid model iEBE-VISHNU with TRENTO initial conditions to study the
collective flow and the fluid behavior in p/d/He+Au collisions. With
fine-tuned parameters, iEBE-VISHNU can describe the and
data from the PHENIX and STAR collaborations. However, for these parameter sets
tuned to fit the STAR data, the hydrodynamic simulations have already beyond
their limits with the average Knudsen number obviously
larger than one. Our calculations demonstrate that, for a meaningful evaluation
of the fluid behavior in the small systems, model simulations should also pay
attention to the validity range of hydrodynamics
DBQ-SSD: Dynamic Ball Query for Efficient 3D Object Detection
Many point-based 3D detectors adopt point-feature sampling strategies to drop
some points for efficient inference. These strategies are typically based on
fixed and handcrafted rules, making difficult to handle complicated scenes.
Different from them, we propose a Dynamic Ball Query (DBQ) network to
adaptively select a subset of input points according to the input features, and
assign the feature transform with suitable receptive field for each selected
point. It can be embedded into some state-of-the-art 3D detectors and trained
in an end-to-end manner, which significantly reduces the computational cost.
Extensive experiments demonstrate that our method can reduce latency by 30%-60%
on KITTI and Waymo datasets. Specifically, the inference speed of our detector
can reach 162 FPS and 30 FPS with negligible performance degradation on KITTI
and Waymo datasets, respectively
High-Qf value and temperature stable Zn2+-Mn4+ cooperated modified cordierite-based microwave and millimeter-wave dielectric ceramics
Cordierite-based dielectric ceramics with a lower dielectric constant would have significant application potential as dielectric resonator and filter materials for future ultra-low-latency 5G/6G millimeter-wave and terahertz communication. In this article, the phase structure, microstructure and microwave dielectric properties of Mg2Al4–2x(Mn0.5Zn0.5)2xSi5O18 (0 ≤ x ≤ 0.3) ceramics are studied by crystal structure refinement, scanning electron microscope (SEM), the theory of complex chemical bonds and infrared reflectance spectrum. Meanwhile, complex double-ions coordinated substitution and two-phase complex methods were used to improve its Q×f value and adjust its temperature coefficient. The Q×f values of Mg2Al4–2x(Mn0.5Zn0.5)2xSi5O18 single-phase ceramics are increased from 45,000 [email protected] GHz (x = 0) to 150,500 [email protected] GHz (x = 0.15) by replacing Al3+ with Zn2+-Mn4+. The positive frequency temperature coefficient additive TiO2 is used to prepare the temperature stable Mg2Al3.7(Mn0.5Zn0.5)0.3Si5O18-ywt%TiO2 composite ceramic. The composite ceramic of Mg2Al3.7(Mn0.5Zn0.5)0.3Si5O18-ywt%TiO2 (8.7 wt% ≤ y ≤ 10.6 wt%) presents the near-zero frequency temperature coefficient at 1225 °C sintering temperature: εr = 5.68, Q×f = 58,040 GHz, τf = −3.1 ppm/°C (y = 8.7 wt%) and εr = 5.82, Q×f = 47,020 GHz, τf = +2.4 ppm/°C (y = 10.6 wt%). These findings demonstrate promising application prospects for 5 G and future microwave and millimeter-wave wireless communication technologies
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