1,999 research outputs found
Mutton Traceability Method Based on Internet of Things
In order to improve the mutton traceability efficiency for Internet of Things and solve the problem of data transmission, analyzed existing tracking algorithm, proposed the food traceability application model, Petri network model of food traceability and food traceability of time series data of improved K-means algorithm based on the Internet of things. The food traceability application model to convert, integrate and mine the heterogeneous information, implementation of the food safety traceability information management, Petri network model for food traceability in the process of the state transition were analyzed and simulated and provides a theoretical basis to study the behavior described in the food traceability system and structural design. The experiments on simulation data show that the proposed traceability method based on Internet of Things is more effective for mutton traceability data than the traditional K-means methods
3-Bromo-N′-(2-hydrÂoxy-3,5-diiodoÂbenzylÂidene)benzohydrazide monohydrate
Crystals of the title compound, C14H9BrI2N2O2·H2O, were obtained from a condensation reaction of 3-bromoÂbenzohydrazide with 3,5-diiodoÂsalicylaldehyde. The Schiff base molÂecule assumes an E configuration with respect to the C=N bond, and the dihedral angle between the two benzene rings is 6.9 (2)°. An intraÂmolecular O—H⋯N hydrogen bond is observed in the Schiff base molÂecule and may contribute to its overall near planarity. In the crystal structure, molÂecules are linked through interÂmolecular O—H⋯O and N—H⋯O hydrogen bonds, forming layers parallel to the bc plane. Short interÂmolecular I⋯O contacts [2.930 (5) Å] are also found, linking the molÂecules into zigzag chains along b
Revealing inherent quantum interference and entanglement of a Dirac Fermion
The Dirac equation is critical to understanding the universe, and plays an
important role in technological advancements. Compared to the stationary
solution, the dynamical evolution under the Dirac Hamiltonian is less
understood, exemplified by Zitterbewegung. Although originally predicted in
relativistic quantum mechanics, Zitterbewegung can also appear in some
classical systems, which leads to the important question of whether
Zitterbewegung of Dirac Fermions is underlain by a more fundamental and
universal interference behavior without classical analogs. We here reveal such
an interference pattern in phase space, which underlies but goes beyond
Zitterbewegung, and whose nonclassicality is manifested by the negativity of
the phase-space quasiprobability distribution, and the associated
pseudospin-momentum entanglement. We confirm this discovery by numerical
simulation and an on-chip experiment, where a superconducting qubit and a
quantized microwave field respectively emulate the internal and external
degrees of freedom of a Dirac particle. The measured quasiprobability
negativities well agree with the numerical simulation. Besides being of
fundamental importance, the demonstrated nonclassical effects are useful in
quantum technology.Comment: 18 pages, 15 figure
Dense network of one-dimensional mid-gap metallic modes in monolayer MoSe2 and their spatial undulations
We report the observation of a dense triangular network of one-dimensional
(1D) metallic modes in a continuous and uniform monolayer of MoSe2 grown by
molecular-beam epitaxy. High-resolution transmission electron microscopy and
scanning tunneling microscopy and spectroscopy (STM/STS) studies show these 1D
modes are mid-gap states at inversion domain boundaries. STM/STS measurements
further reveal intensity undulations of the metallic modes, presumably arising
from the superlattice potentials due to moire pattern and the quantum
confinement effect. A dense network of the metallic modes with high density of
states is of great potential for heterocatalysis applications. The
interconnection of such mid-gap 1D conducting channels may also imply new
transport behaviors distinct from the 2D bulk
From Adversarial Arms Race to Model-centric Evaluation: Motivating a Unified Automatic Robustness Evaluation Framework
Textual adversarial attacks can discover models' weaknesses by adding
semantic-preserved but misleading perturbations to the inputs. The long-lasting
adversarial attack-and-defense arms race in Natural Language Processing (NLP)
is algorithm-centric, providing valuable techniques for automatic robustness
evaluation. However, the existing practice of robustness evaluation may exhibit
issues of incomprehensive evaluation, impractical evaluation protocol, and
invalid adversarial samples. In this paper, we aim to set up a unified
automatic robustness evaluation framework, shifting towards model-centric
evaluation to further exploit the advantages of adversarial attacks. To address
the above challenges, we first determine robustness evaluation dimensions based
on model capabilities and specify the reasonable algorithm to generate
adversarial samples for each dimension. Then we establish the evaluation
protocol, including evaluation settings and metrics, under realistic demands.
Finally, we use the perturbation degree of adversarial samples to control the
sample validity. We implement a toolkit RobTest that realizes our automatic
robustness evaluation framework. In our experiments, we conduct a robustness
evaluation of RoBERTa models to demonstrate the effectiveness of our evaluation
framework, and further show the rationality of each component in the framework.
The code will be made public at \url{https://github.com/thunlp/RobTest}.Comment: Accepted to Findings of ACL 202
Nitrogen isotope composition of ammonium in PM 2.5 in the Xiamen, China: impact of non-agricultural ammonia
Abstract(#br)Since NH 3 is a significant precursor to ammonium in PM 2.5 and contributes significantly to atmospheric nitrogen deposition but largely remains unregulated in China, the insight into the source of NH 3 emissions by the isotopic investigation is important in controlling NH 3 emissions. In this study, atmospheric concentrations of NH 3 and water-soluble ion composition in PM 2.5 as well as nitrogen isotope ratios in NH 4 + (δ 15 N-NH 4 + ) in Xiamen, China, were measured. Results showed that average NH 3 concentration for the five sites in Xiamen was 7.9 μg m −3 with distinct higher values in the warm season and lower values in the cold season, and PM 2.5 concentration for the two sites (urban and suburban) was 59.2 μg m −3 with lowest values in summer. In the PM 2.5 , NH 4 +..
Nitrogen isotope composition of ammonium in PM2.5 in the Xiamen, China: impact of non-agricultural ammonia.
Since NH3 is a significant precursor to ammonium in PM2.5 and contributes significantly to atmospheric nitrogen deposition but largely remains unregulated in China, the insight into the source of NH3 emissions by the isotopic investigation is important in controlling NH3 emissions. In this study, atmospheric concentrations of NH3 and water-soluble ion composition in PM2.5 as well as nitrogen isotope ratios in NH4+ (δ15N-NH4+) in Xiamen, China, were measured. Results showed that average NH3 concentration for the five sites in Xiamen was 7.9 μg m-3 with distinct higher values in the warm season and lower values in the cold season, and PM2.5 concentration for the two sites (urban and suburban) was 59.2 μg m-3 with lowest values in summer. In the PM2.5, NH4+ concentrations were much lower than NH3 and showed a stronger positive correlation with NO3- than that with SO42- suggesting the formation of NH4NO3 and equilibrium between NH3 and NH4+. Although the concentrations of NH3 at the urban site were significantly higher than those at the suburban site, no significant spatial difference in NH4+ and δ15N-NH4+ was obtained. The distinct heavier δ15N-NH4+ values in summer than in other seasons correlated well with the equilibrium isotopic effects between NH3 and NH4+ which depend on temperature. The initial δ15N-NH3 values were in the range of waste treatment (- 25.42‰) and fossil fuel combustion (- 2.5‰) after accounting for the isotope fractionation. The stable isotope mixing model showed that fossil fuel-related NH3 emissions (fossil fuel combustion and NH3 slip) contributed more than 70% to aerosol NH4+. This finding suggested that the reduction of NH3 emissions from urban transportation and coal combustion should be a priority in the abatement of PM2.5 pollution in Xiamen
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