10 research outputs found
Topological Anderson Insulators by homogenization theory
A central property of (Chern) topological insulators is the presence of
robust asymmetric transport along interfaces separating two-dimensional
insulating materials in different topological phases. A Topological Anderson
Insulator is an insulator whose topological phase is induced by spatial
fluctuations.
This paper proposes a mathematical model of perturbed Dirac equations and
shows that for sufficiently large and highly oscillatory perturbations, the
systems is in a different topological phase than the unperturbed model. In
particular, a robust asymmetric transport indeed appears at an interface
separating perturbed and unperturbed phases.
The theoretical results are based on careful estimates of resolvent operators
in the homogenization theory of Dirac equations and on the characterization of
topological phases by the index of an appropriate Fredholm operator
THE QUALITY WATER ENVIRONMENT HAPPENING OF THE HUONG RIVER IN THE HUE CITY, PERIOD OF 2003-2006
Joint Research on Environmental Science and Technology for the Eart
Explicit corrector in homogenization of monotone operators and its application to nonlinear dielectric elastomer composites
This paper concerns the rigorous periodic homogenization for a weakly coupled
electroelastic system of a nonlinear electrostatic equation with an elastic
equation enriched with electrostriction. Such coupling is employed to describe
dielectric elastomers or deformable (elastic) dielectrics. It is shown that the
effective response of the system consists of a homogeneous dielectric elastomer
described by a nonlinear weakly coupled system of PDEs whose coefficients
depend on the coefficients of the original heterogeneous material, the geometry
of the composite and the periodicity of the original microstructure. The
approach developed here for this nonlinear problem allows obtaining an explicit
corrector result for the homogenization of monotone operators with minimal
regularity assumptions. Two gradient estimates for elastic systems with
discontinuous coefficients are also obtained.Comment: We provide a new proof to extend the explicit first-order corrector
result in the first version of this paper. The new explicit corrector result
(cf. Theorem 1) holds globally and unifies the previous classical correct
results in homogenization of the divergence equation (both linear and
nonlinear). New references are added. Comments are welcome
Pedagogy undergraduates’ perception on twenty-first century skills
Teachers head up their students to the bright future, their role is indispensable, especially in the 21st
century, which expects them to be energetic and flexible to apply knowledge to the daily life and carrier
task. Examining the perception on 21st century skills teaching of pedagogy teacher-to-be
undergraduates - plays a vital role in identifying deficits in teachers’ professional development; as well
as organizing training programs to enhance their knowledge and skills. To the best of our knowledge,
no study to date has examined pedagogy undergraduates’ perception in Vietnam. This study aimed at
examining Vietnamese undergraduates' perception on teaching the 21st century skills. Our crosssectional study used the 21st Century Skills Teaching Scale. Descriptive analysis and ANOVA were
performed in this research. The results showed that: (1) Vietnamese pedagogy students had a high level
of perception on teaching the 21st century skills; (2) there was no gender difference in their perception;
and (3) there was no significant difference in their perception regard to their school years and (4) there
was significant difference between those having joined soft skill courses at their university and those
having not joined anyone
Surface-based protein domains retrieval methods from a SHREC2021 challenge
publication dans une revue suite à la communication hal-03467479 (SHREC 2021: surface-based protein domains retrieval)International audienceProteins are essential to nearly all cellular mechanism and the effectors of the cells activities. As such, they often interact through their surface with other proteins or other cellular ligands such as ions or organic molecules. The evolution generates plenty of different proteins, with unique abilities, but also proteins with related functions hence similar 3D surface properties (shape, physico-chemical properties, …). The protein surfaces are therefore of primary importance for their activity. In the present work, we assess the ability of different methods to detect such similarities based on the geometry of the protein surfaces (described as 3D meshes), using either their shape only, or their shape and the electrostatic potential (a biologically relevant property of proteins surface). Five different groups participated in this contest using the shape-only dataset, and one group extended its pre-existing method to handle the electrostatic potential. Our comparative study reveals both the ability of the methods to detect related proteins and their difficulties to distinguish between highly related proteins. Our study allows also to analyze the putative influence of electrostatic information in addition to the one of protein shapes alone. Finally, the discussion permits to expose the results with respect to ones obtained in the previous contests for the extended method. The source codes of each presented method have been made available online
Calibration of a passive sampling device for the determination of nitrogen dioxide in ambient air
Nitrogen dioxide (NO2), a common air pollutant, has been widely admitted to be harmful to both the environment and human health, demanding its well-control procedure and corresponding quantification. In this study, NO2 in ambient air was collected by a passive sampling method using the Willems badge diffusive sampler, followed by a derivatization step with the Griess-Saltzman solution, and analyzed by ultraviolet-visible (UV–vis) spectroscopy at 543 nm. The device can be utilized for 168 h of continuous field sampling. The experimental sampling rate (Ke) of (4.02 ± 0.29) × 10−3 m3 h − 1 with a relative standard deviation (% RSD) of 9.6 % was determined by conducting parallel experiments between an active sampling method (ISO 6768:1998) and the Willems samplers. After exposure time, samplers could be stored for two weeks in a refrigerator at 4 °C before analyzing. The studied passive diffusive sampler was simple, low-cost, easy to reuse; permitted determining the average concentration of NO2 in ambient air. The average NO2 concentrations for 2-hour to 4-hour sampling periods at different studied sampling sites in Ho Chi Minh city (Vietnam) were ranged from 11.5 to 189 μg m − 3
SHREC 2021: surface-based protein domains retrieval
Oral. 3DOR is the dedicated workshop series for methods, applications and benchmark-based evaluation of 3D object retrieval, classification, and similarity-based object processing. The workshop also includes the 2021 edition of the 3D Shape Retrieval Challenge (SHREC). Accepted full papers will be published in Computers & Graphics Journal (Elsevier), and accepted short papers will appear in the Eurographics Digital Library.International audienceProteins are essential to nearly all cellular mechanism, and often interact through their surface with other cell molecules, such as proteins and ligands. The evolution generates plenty of different proteins, with unique abilities, but also proteins with related functions hence surface, which is therefore of primary importance for their activity. In the present work, we assess the ability of five methods to retrieve similar protein surfaces, using either their shape only (3D meshes), or their shape and the electrostatic potential at their surface, an important surface property. Five different groups participated in this challenge using the shape only, and one group extended its pre-existing algorithm to handle the electrostatic potential. The results reveal both the ability of the methods to detect related proteins and their difficulties to distinguish between topologically related proteins
SHREC 2021 Track:Retrieval and classification of protein surfaces equipped with physical and chemical properties
This paper presents the methods that have participated in the SHREC 2021
contest on retrieval and classification of protein surfaces on the basis of
their geometry and physicochemical properties. The goal of the contest is to
assess the capability of different computational approaches to identify
different conformations of the same protein, or the presence of common
sub-parts, starting from a set of molecular surfaces. We addressed two
problems: defining the similarity solely based on the surface geometry or with
the inclusion of physicochemical information, such as electrostatic potential,
amino acid hydrophobicity, and the presence of hydrogen bond donors and
acceptors. Retrieval and classification performances, with respect to the
single protein or the existence of common sub-sequences, are analysed according
to a number of information retrieval indicators
SHREC\u2717: RgB-D to CAD Retrieval With ObjectNN Dataset
© 2017 The Eurographics Association. The goal of this track is to study and evaluate the performance of 3D object retrieval algorithms using RGB-D data. This is inspired from the practical need to pair an object acquired from a consumer-grade depth camera to CAD models available in public datasets on the Internet. To support the study, we propose ObjectNN, a new dataset with well segmented and annotated RGB-D objects from SceneNN [HPN∗16] and CAD models from ShapeNet [CFG∗15]. The evaluation results show that the RGB-D to CAD retrieval problem, while being challenging to solve due to partial and noisy 3D reconstruction, can be addressed to a good extent using deep learning techniques, particularly, convolutional neural networks trained by multi-view and 3D geometry. The best method in this track scores 82% in accuracy
RGB-D to CAD retrieval with objectNN dataset
The goal of this track is to study and evaluate the performance of 3D object retrieval algorithms using RGB-D data. This is inspired from the practical need to pair an object acquired from a consumer-grade depth camera to CAD models available in public datasets on the Internet. To support the study, we propose ObjectNN, a new dataset with well segmented and annotated RGB-D objects from SceneNN [HPN*16] and CAD models from ShapeNet [CFG*15]. The evaluation results show that the RGB-D to CAD retrieval problem, while being challenging to solve due to partial and noisy 3D reconstruction, can be addressed to a good extent using deep learning techniques, particularly, convolutional neural networks trained by multi-view and 3D geometry. The best method in this track scores 82% in accuracy