3,052 research outputs found
Automatic facial expression tracking for 4D range scans
This paper presents a fully automatic approach of spatio-temporal facial expression tracking for 4D range scans without any manual interventions (such as specifying landmarks). The approach consists of three steps: rigid registration, facial model reconstruction, and facial expression tracking. A Scaling Iterative Closest Points (SICP) algorithm is introduced to compute the optimal rigid registration between a template facial model and a range scan with consideration of the scale problem. A deformable model, physically based on thin shells, is proposed to faithfully reconstruct the facial surface and texture from that range data. And then the reconstructed facial model is used to track facial expressions presented in a sequence of range scans by the deformable model
Implication the observed for studying the process
We study the charmonium reaction using
effective lagrangian approach where the contributions from well established
states are considered, and all parameters are fixed in the process of
at center of mass energy GeV.
The experimental data on the line shape of the mass distribution of the can be well reproduced. Based on the studying of , the total and differential cross sections of the reaction are predicted. At the same time we evaluated
also the cross sections of the reaction. It is
shown that the contribution of nucleon pole to this reaction is largest close
to the reaction threshold. However, the interference between nucleon pole and
the other nucleon resonance can still change the angle distributions
significantly. Those theoretical results may be test by the future experiments
at \overline{\mbox{P}}ANDA.Comment: 8 pages, 10 figures, and 4 tables. More discussions added and typos
corrected. Accepted by Eur. Phys. J.
Anisotropic Electron-Hole Excitation and Large Linear Dichroism in Two-Dimensional Ferromagnet CrSBr with In-Plane Magnetization
The observation of magnetic ordering in atomically thin CrI and
CrGeTe monolayers has aroused intense interest in condensed matter
physics and material science. Studies of van de Waals two-dimensional (2D)
magnetic materials are of both fundamental importance and application interest.
In particular, exciton-enhanced magneto-optical properties revealed in CrI
and CrBr monolayers have expanded the understanding of exciton physics in
2D materials. Unlike CrI and CrBr with out-of-plane magnetization,
CrSBr has an in-plane magnetic moment, therefore, providing a good opportunity
to study the magnetic linear dichroism and high-order magneto-optical effects.
Here, based on the many-body perturbation method within density-functional
theory, we have studied quasiparticle electronic structure, exciton, and
optical properties in CrSBr monolayer. Strongly bounded exciton has been
identified with the first bright exciton located at 1.35 eV, in good agreement
with an experiment of photoluminescence (Nat. Mater. \textbf{20}, 1657 (2021)).
Strong contrast in the optical absorption is found between the electric fields
lying along the in-plane two orthogonal directions. In accordance with a
typical and realistic experimental setup, we show that the rotation angle of
linear polarized light, either reflected or transmitted, could be comparable
with those revealed in black phosphorene. Such large linear dichroism arises
mainly from anisotropic in-plane crystal structure. The magnetic contribution
from the off-diagonal component of dielectric function to the linear dichroism
in CrSBr is negligible. Our findings not only have revealed excitonic effect on
the optical and magneto-optical properties in 2D ferromagnet CrSBr, but also
have shown its potential applications in 2D optics and optoelectronics.Comment: 47 pages, 24 figure
4,4′-(Propane-1,3-diyl)dipyridinium tetrachloridonickelate(II)
The title compound, (C13H16N2)[NiCl4] or (H2bpp)·NiCl4 [bpp is 1,3-bis(4-pyridyl)propane], is isostructural with its already reported Cu, Zn and Hg analogues. The structure consists of a doubly charged (H2bpp)2+ cation and a tetrahedral [NiCl4]2− dianion. Both pyridyl N atoms are protonated and form a (H2bpp)2+ cation which adopts an anti–anti conformation with a dihedral angle of 6.287 (7)° between the pyridyl rings. The two pyridyl N atoms are both involved in strong N—H⋯Cl hydrogen bonds, which link both units into a dimer
Volumetric-mapping-based inverse design of 3D architected materials and mobility control by topology reconstruction
The recent development of modular origami structures has ushered in a new era
for active metamaterials with multiple degrees of freedom (multi-DOF). Notably,
no systematic inverse design approach for volumetric modular origami structures
has been reported. Moreover, very few topologies of modular origami have been
studied for the design of active metamaterials with multi-DOF. Herein, we
develop an inverse design method and reconfigurable algorithm for constructing
3D active architected structures - we synthesize modular origami structures
that can be volumetrically mapped to a target 3D shape. We can control the
reconfigurability by reconstructing the topology of the architected structures.
Our inverse design based on volumetric mapping with mobility control by
topology reconstruction can be used to construct architected metamaterials with
any 3D complex shape that are also transformable with multi-DOF. Our work opens
a new path toward 3D reconfigurable structures based on volumetric inverse
design. This work is significant for the design of 3D active metamaterials and
3D morphing devices for automotive, aerospace, and biomedical engineering
applications.Comment: 36 page
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