293 research outputs found
Assessing the impacts of phosphorus inactive clay on phosphorus release control and phytoplankton community structure in eutrophic lakes
Addressing the challenge that phosphorus is the key factor and cause for eutrophication, we evaluated the phosphorus release control performance of a new phosphorus inactive clay (PIC) and compared with Phoslock(®). Meanwhile, the impacts of PIC and Phoslock(®) on phytoplankton abundance and community structure in eutrophic water were also discussed. With the dosage of 40 mg/L, PIC effectively removed 97.7% of total phosphorus (TP) and 98.3% of soluble reactive phosphorus (SRP) in eutrophic waters. In sediments, Fe/Al-phosphorus and organic phosphorus remained stable whereas Ca-phosphorus had a significant increase of 13.1%. The results indicated that PIC may form the active overlay at water-sediment interface and decrease the bioavailability of phosphorus. The phytoplankton abundance was significantly reduced by PIC and decreased from (1.0-2.4) × 10(7) cells/L to (1.3-4.3) × 10(6) cells/L after 15 d simultaneous experiment. The phytoplankton community structure was also altered, where Cyanobacteria and Bacillariophyceae were the most inhibited and less dominant due to their sensitivity to phosphorus. After PIC treatment, the residual lanthanum concentration in water was 1.44-3.79 μg/L, and the residual aluminium concentration was low as 101.26-103.72 μg/L, which was much less than the recommended concentration of 200 μg/L. This study suggests that PIC is an appropriate material for phosphorus inactivation and algal bloom control, meaning its huge potential application in eutrophication restoration and management
Cross-Modality High-Frequency Transformer for MR Image Super-Resolution
Improving the resolution of magnetic resonance (MR) image data is critical to
computer-aided diagnosis and brain function analysis. Higher resolution helps
to capture more detailed content, but typically induces to lower
signal-to-noise ratio and longer scanning time. To this end, MR image
super-resolution has become a widely-interested topic in recent times. Existing
works establish extensive deep models with the conventional architectures based
on convolutional neural networks (CNN). In this work, to further advance this
research field, we make an early effort to build a Transformer-based MR image
super-resolution framework, with careful designs on exploring valuable domain
prior knowledge. Specifically, we consider two-fold domain priors including the
high-frequency structure prior and the inter-modality context prior, and
establish a novel Transformer architecture, called Cross-modality
high-frequency Transformer (Cohf-T), to introduce such priors into
super-resolving the low-resolution (LR) MR images. Comprehensive experiments on
two datasets indicate that Cohf-T achieves new state-of-the-art performance
Novel MSVPWM to Reduce the Inductor Current Ripple for Z-Source Inverter in Electric Vehicle Applications
A novel modified space vector pulse width modulation (MSVPWM) strategy for Z-Source inverter is presented. By rearranging the position of shoot-through states, the frequency of inductor current ripple is kept constant. Compared with existing MSVPWM strategies, the proposed approach can reduce the maximum inductor current ripple. So the volume of Z-source network inductor can be designed smaller, which brings the beneficial effect on the miniaturization of the electric vehicle controller. Theoretical findings in the novel MSVPWM for Z-Source inverter have been verified by experiment results
WMFormer++: Nested Transformer for Visible Watermark Removal via Implict Joint Learning
Watermarking serves as a widely adopted approach to safeguard media
copyright. In parallel, the research focus has extended to watermark removal
techniques, offering an adversarial means to enhance watermark robustness and
foster advancements in the watermarking field. Existing watermark removal
methods mainly rely on UNet with task-specific decoder branches--one for
watermark localization and the other for background image restoration. However,
watermark localization and background restoration are not isolated tasks;
precise watermark localization inherently implies regions necessitating
restoration, and the background restoration process contributes to more
accurate watermark localization. To holistically integrate information from
both branches, we introduce an implicit joint learning paradigm. This empowers
the network to autonomously navigate the flow of information between implicit
branches through a gate mechanism. Furthermore, we employ cross-channel
attention to facilitate local detail restoration and holistic structural
comprehension, while harnessing nested structures to integrate multi-scale
information. Extensive experiments are conducted on various challenging
benchmarks to validate the effectiveness of our proposed method. The results
demonstrate our approach's remarkable superiority, surpassing existing
state-of-the-art methods by a large margin
CALICO: Self-Supervised Camera-LiDAR Contrastive Pre-training for BEV Perception
Perception is crucial in the realm of autonomous driving systems, where
bird's eye view (BEV)-based architectures have recently reached
state-of-the-art performance. The desirability of self-supervised
representation learning stems from the expensive and laborious process of
annotating 2D and 3D data. Although previous research has investigated
pretraining methods for both LiDAR and camera-based 3D object detection, a
unified pretraining framework for multimodal BEV perception is missing. In this
study, we introduce CALICO, a novel framework that applies contrastive
objectives to both LiDAR and camera backbones. Specifically, CALICO
incorporates two stages: point-region contrast (PRC) and region-aware
distillation (RAD). PRC better balances the region- and scene-level
representation learning on the LiDAR modality and offers significant
performance improvement compared to existing methods. RAD effectively achieves
contrastive distillation on our self-trained teacher model. CALICO's efficacy
is substantiated by extensive evaluations on 3D object detection and BEV map
segmentation tasks, where it delivers significant performance improvements.
Notably, CALICO outperforms the baseline method by 10.5% and 8.6% on NDS and
mAP. Moreover, CALICO boosts the robustness of multimodal 3D object detection
against adversarial attacks and corruption. Additionally, our framework can be
tailored to different backbones and heads, positioning it as a promising
approach for multimodal BEV perception
- …