166 research outputs found
Electromagnetic Reinforced Carbon Fiber Composite Case and Its Electromagnetic Pulse Protection Performance
We adopt the technology of electromagnetic strengthening carbon fiber composite material to improve its electromagnetic protection ability, and use it to prepare the sample of carbon fiber composite cabinet, through the test, it has good electromagnetic pulse protection performance. Based on the carbon fiber composite structure design and electric connection design of the interlamination and gap electromagnetic enforcement. The HEMP protection performance was tested under the GB/T18039.10-2018 standard and the results showed that the HEMP shielding efficiency were above 65 dB. The carbon fiber composite cabinet had the lightweight ,high strength,HEMP shielding and anti-severe environment characteristics. The carbon fiber composite cabinet has a project value and application prospect
Predicted T-XY (XY=P, As and Sb) monolayer with intrinsic persistent spin helix and large piezoelectric response
The persistent spin helix (PSH) is robust against spin-independent scattering
and renders an extremely long spin lifetime, which can improve the performance
of potential spintronic devices. To achieve the PSH, a unidirectional spin
configuration is required in the momentum space. Here, T-XY (XY=P, As and
Sb) monolayers with dynamical, mechanical and thermal stabilities are predicted
to intrinsically possess PSH. Due to the point-group symmetry,
a unidirectional spin configuration is preserved in the out-of-plane direction
for both conduction and valence bands around the high-symmetry point.
That is, the expectation value of the spin only has the out-of-plane
component . The application of an out-of-plane external electric field can
induce in-plane components and , thus offering a promising platform
for the on-off logical functionality of spin devices. T-XY (XY=P, As and
Sb) monolayers are determined to be excellent two-dimensional (2D)
piezoelectric materials. The in-plane piezoelectric coefficient
(absolute value) of T-SbP is 226.15 pm/V, which is larger than that reported
for most 2D materials, providing possibility of tuning spin-splitting of PSH by
in-plane electric field induced with a uniaxial in-plane strain through
piezoelectric effect. Our work reveals a new family of T-phase 2D materials,
which could provide promising applications in spintronic and piezoelectric
devices.Comment: 8 pages, 9 figure
Ganoderic acid A potentiates antioxidant effect and protection of mitochondrial membrane and reduction the apoptosis rate in primary hippocampal neurons treated with magnesium free medium
Group Equivariant BEV for 3D Object Detection
Recently, 3D object detection has attracted significant attention and
achieved continuous improvement in real road scenarios. The environmental
information is collected from a single sensor or multi-sensor fusion to detect
interested objects. However, most of the current 3D object detection approaches
focus on developing advanced network architectures to improve the detection
precision of the object rather than considering the dynamic driving scenes,
where data collected from sensors equipped in the vehicle contain various
perturbation features. As a result, existing work cannot still tackle the
perturbation issue. In order to solve this problem, we propose a group
equivariant bird's eye view network (GeqBevNet) based on the group equivariant
theory, which introduces the concept of group equivariant into the BEV fusion
object detection network. The group equivariant network is embedded into the
fused BEV feature map to facilitate the BEV-level rotational equivariant
feature extraction, thus leading to lower average orientation error. In order
to demonstrate the effectiveness of the GeqBevNet, the network is verified on
the nuScenes validation dataset in which mAOE can be decreased to 0.325.
Experimental results demonstrate that GeqBevNet can extract more rotational
equivariant features in the 3D object detection of the actual road scene and
improve the performance of object orientation prediction.Comment: 8 pages,3 figures,accepted by International Joint Conference on
Neural Networks (IJCNN)202
Assessment of Vegetation Dynamics and Ecosystem Resilience in the Context of Climate Change and Drought in the Horn of Africa
Understanding the response of vegetation and ecosystem resilience to climate variability and drought conditions is essential for ecosystem planning and management. In this study, we assessed the vegetation changes and ecosystem resilience in the Horn of Africa (HOA) since 2000 and detected their drivers based mainly on analysis of the Moderate Resolution Imaging Spectroradiometer (MODIS) products. We found that the annual and seasonal trends of NDVI (Normalized Difference Vegetation Index) generally increased during the last two decades over the Horn of Africa particularly in western parts of Ethiopia and Kenya. The weakest annual and seasonal NDVI trends were observed over the grassland cover and tropical arid agroecological zones. The NDVI variation negatively correlated with Land Surface Temperature (LST) and positively correlated with precipitation at a significant level (p < 0.05) account for 683,197 km2 and 533,385 km2 area, respectively. The ecosystem Water Use Efficiency (eWUE) showed overall increasing trends with larger values for the grassland biome. The precipitation had the most significant effect on eWUE variation compared to LST and annual SPEI (Standardized Evapotranspiration Index). There were about 54.9% of HOA resilient to drought disturbance, whereas 32.6% was completely not-resilient. The ecosystems in the humid agroecological zones, the cropland, and wetland were slightly not-resilient to severe drought conditions in the region. This study provides useful information for policy makers regarding ecosystem and dryland management in the context of climate change at both national and regional levels
Assessment of Vegetation Dynamics and Ecosystem Resilience in the Context of Climate Change and Drought in the Horn of Africa
Understanding the response of vegetation and ecosystem resilience to climate variability and drought conditions is essential for ecosystem planning and management. In this study, we assessed the vegetation changes and ecosystem resilience in the Horn of Africa (HOA) since 2000 and detected their drivers based mainly on analysis of the Moderate Resolution Imaging Spectroradiometer (MODIS) products. We found that the annual and seasonal trends of NDVI (Normalized Difference Vegetation Index) generally increased during the last two decades over the Horn of Africa particularly in western parts of Ethiopia and Kenya. The weakest annual and seasonal NDVI trends were observed over the grassland cover and tropical arid agroecological zones. The NDVI variation negatively correlated with Land Surface Temperature (LST) and positively correlated with precipitation at a significant level (p < 0.05) account for 683,197 km2 and 533,385 km2 area, respectively. The ecosystem Water Use Efficiency (eWUE) showed overall increasing trends with larger values for the grassland biome. The precipitation had the most significant effect on eWUE variation compared to LST and annual SPEI (Standardized Evapotranspiration Index). There were about 54.9% of HOA resilient to drought disturbance, whereas 32.6% was completely not-resilient. The ecosystems in the humid agroecological zones, the cropland, and wetland were slightly not-resilient to severe drought conditions in the region. This study provides useful information for policy makers regarding ecosystem and dryland management in the context of climate change at both national and regional levels
Recovering lossless propagation of polaritons with synthesized complex frequency excitation
Surface plasmon polaritons and phonon polaritons offer a means of surpassing
the diffraction limit of conventional optics and facilitate efficient energy
storage, local field enhancement, high sensitivities, benefitting from their
subwavelength confinement of light. Unfortunately, losses severely limit the
propagation decay length, thus restricting the practical use of polaritons.
While optimizing the fabrication technique can help circumvent the scattering
loss of imperfect structures, the intrinsic absorption channel leading to heat
production cannot be eliminated. Here, we utilize synthetic optical excitation
of complex frequency with virtual gain, synthesized by combining the
measurements taken at multiple real frequencies, to restore the lossless
propagations of phonon polaritons with significantly reduced intrinsic losses.
The concept of synthetic complex frequency excitation represents a viable
solution to compensate for loss and would benefit applications including
photonic circuits, waveguiding and plasmonic/phononic structured illumination
microscopy.Comment: 20 pages, 4 figure
Comparative genomic analyses of Mycoplasma hyopneumoniae pathogenic 168 strain and its high-passaged attenuated strain
Background: Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia (EP), a mild, chronic pneumonia of swine. Despite presenting with low direct mortality, EP is responsible for major economic losses in the pig industry. To identify the virulence-associated determinants of M. hyopneumoniae, we determined the whole genome sequence of M. hyopneumoniae strain 168 and its attenuated high-passage strain 168-L and carried out comparative genomic analyses. Results: We performed the first comprehensive analysis of M. hyopneumoniae strain 168 and its attenuated strain and made a preliminary survey of coding sequences (CDSs) that may be related to virulence. The 168-L genome has a highly similar gene content and order to that of 168, but is 4,483 bp smaller because there are 60 insertions and 43 deletions in 168-L. Besides these indels, 227 single nucleotide variations (SNVs) were identified. We further investigated the variants that affected CDSs, and compared them to reported virulence determinants. Notably, almost all of the reported virulence determinants are included in these variants affected CDSs. In addition to variations previously described in mycoplasma adhesins (P97, P102, P146, P159, P216, and LppT), cell envelope proteins (P95), cell surface antigens (P36), secreted proteins and chaperone protein (DnaK), mutations in genes related to metabolism and growth may also contribute to the attenuated virulence in 168-L. Furthermore, many mutations were located in the previously described repeat motif, which may be of primary importance for virulence. Conclusions: We studied the virulence attenuation mechanism of M. hyopneumoniae by comparative genomic analysis of virulent strain 168 and its attenuated high-passage strain 168-L. Our findings provide a preliminary survey of CDSs that may be related to virulence. While these include reported virulence-related genes, other novel virulence determinants were also detected. This new information will form the foundation of future investigations into the pathogenesis of M. hyopneumoniae and facilitate the design of new vaccines
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