50 research outputs found
TaCA: Upgrading Your Visual Foundation Model with Task-agnostic Compatible Adapter
Visual foundation models like CLIP excel in learning feature representations
from extensive datasets through self-supervised methods, demonstrating
remarkable transfer learning and generalization capabilities. A growing number
of applications based on visual foundation models are emerging, including
innovative solutions such as BLIP-2. These applications employ pre-trained CLIP
models as upstream feature extractors and train various downstream modules to
accomplish diverse tasks. In situations involving system upgrades that require
updating the upstream foundation model, it becomes essential to re-train all
downstream modules to adapt to the new foundation model, which is inflexible
and inefficient. In this paper, we introduce a parameter-efficient and
task-agnostic adapter, dubbed TaCA, that facilitates compatibility across
distinct foundation models while ensuring enhanced performance for the new
models. TaCA allows downstream applications to seamlessly integrate
better-performing foundation models without necessitating retraining. We
conduct extensive experimental validation of TaCA using different scales of
models with up to one billion parameters on various tasks such as video-text
retrieval, video recognition, and visual question answering. The results
consistently demonstrate the emergent ability of TaCA on hot-plugging upgrades
for visual foundation models. Codes and models will be available at
https://github.com/TencentARC/TaCA
The role of 1-octyl-3-methylimidazolium hexafluorophosphate in anticorrosion coating formula development
A hydrophobic ionic liquid (1-octyl-3-methylimidazolium hexafluorophosphate, C8mimPF6) with a function of inhibiting corrosion was encapsulated at different concentrations in the copolymer of poly (methyl methacrylate) and poly (butyl acrylate) through miniemulsion polymerization. These latexes were coated on steel samples whose corrosion properties were evaluated by electrochemical techniques. It was found that increasing the C8mimPF6 concentration from 0 wt% to 30 wt%, the corrosion inhibition efficiency was remarkably improved from 41% to 89% based on the charge transfer resistance and from 64% to 87% based on the corrosion current density, respectively. The ionic liquid did not attend the reaction during latex preparation but behaved as corrosion inhibitors on the steel surface. Such an anticorrosion effect could be ascribed to the physical adsorption of the C8mim+ cation on the reaction sites and the hydrophobicity enhancement resulting from the hydrophobic PF6− anion
Synergistic Effects of 1-Octyl-3-Methylimidazolium Hexafluorophosphate and Cellulose Nanocrystals on Improving Polyacrylate Waterborne Anti-Corrosion Coatings
In this study, three copolymers of poly(methyl methacrylate) and poly(butyl acrylate) (PMMA-co-PBA) latex containing 1-octyl-3 methylimidazolium hexafluorophosphate (C8mimPF6), cellulose nanocrystals (CNCs), and C8mimPF6-CNCs were successfully synthesized through mini emulsion polymerization. These novel composites were each coated on mild steel panels and tested for their anti-corrosion performance by immersion of the coated samples in 3.5 wt% sodium chloride (NaCl) solution over a certain period. The synergistic anti-corrosion effects of the C8mimPF6-CNCs sample led to the highest coating resistance, charge transfer resistance, and corrosion inhibition efficiency and the lowest diffusion coefficient and corrosion rate. The proposed synergistic mechanism revealed that CNCs enhanced the barrier effect of the coating while C8mimPF6 inhibited corrosion when released
High-efficiently visible light-responsive photocatalysts: Ag3PO4 tetrahedral microcrystals with exposed {111} facets of high surface energy
National Basic Research Program of China [2011CBA00508, 2013CB933901]; National Natural Science Foundation of China [21333008, 21131005, 21021061, 21171141]In this article, single-crystalline tetrahedral Ag3PO4 microcrystals with exposed {111} facets was successfully synthesized via a facile wet chemical method. The tetrahedral Ag3PO4 with exposed {111} facets showed the highest photocatalytic activity in visible light irradiation among the {111}, {110} and {100} facets. By DFT calculations, it is demonstrated that the surface energy of the {111} facets is higher than that of the {110} and {100} facets. It was found that the largest band gap of the Ag3PO4 {111} surface is likely to suppress the recombination of electron-hole pairs by exploring the electronic structures of the different surfaces of Ag3PO4. Meanwhile, the dispersion between the valence bands and conduction bands of the {111} surface is beneficial for the separation of photogenerated electrons and holes on the {111} surface, which further improves the photocatalytic activity of the {111} surface
Nano-channel-based physical and chemical synergic regulation for dendrite-free lithium plating
Uncontrollable dendrite growth resulting from the non-uniform lithium ion (Li+) flux and volume expansion in lithium metal (Li) negative electrode leads to rapid performance degradation and serious safety problems of lithium metal batteries. Although N-containing functional groups in carbon materials are reported to be effective to homogenize the Li+ flux, the effective interaction distance between lithium ions and N-containing groups should be relatively small (down to nanometer scale) according to the Debye length law. Thus, it is necessary to carefully design the microstructure of N-containing carbon materials to make the most of their roles in regulating the Li+ flux. In this work, porous carbon nitride microspheres (PCNMs) with abundant nanopores have been synthesized and utilized to fabricate a uniform lithiophilic coating layer having hybrid pores of both the nano- and micrometer scales on the Cu/Li foil. Physically, the three-dimensional (3D) porous framework is favorable for absorbing volume changes and guiding Li growth. Chemically, this coating layer can render a suitable interaction distance to effectively homogenize the Li+ flux and contribute to establishing a robust and stable solid electrolyte interphase (SEI) layer with Li-F, Li-N, and Li-O-rich contents based on the Debye length law. Such a physical-chemical synergic regulation strategy using PCNMs can lead to dendrite-free Li plating, resulting in a low nucleation overpotential and stable Li plating/stripping cycling performance in both the Li‖Cu and the Li‖Li symmetric cells. Meanwhile, a full cell using the PCNM coated Li foil negative electrode and a LiFePO4 positive electrode has delivered a high capacity retention of ∼ 80% after more than 200 cycles at 1 C and achieved a remarkable rate capability. The pouch cell fabricated by pairing the PCNM coated Li foil negative electrode with a NCM 811 positive electrode has retained ∼ 73% of the initial capacity after 150 cycles at 0.2 C
A High Accuracy Time-Reversal Based WiFi Indoor Localization Approach with a Single Antenna
In this paper, we study the influence of multipath magnitude, bandwidth, and communication link number on the performance of the existing time-reversal (TR) based fingerprinting localization approach and find that the localization accuracy deteriorates with a limited bandwidth. To improve the localization performance, by exploiting two unique location-specified signatures extracted from Channel State Information (CSI), we propose a high accuracy TR fingerprint localization approach, HATRFLA. Furthermore, we employ a density-based spatial clustering algorithm to minimize the storage space of the fingerprint database by adaptively selecting the optimal number of fingerprints for each location. Experimental results confirm that the proposed approach can efficiently mitigate accuracy deterioration caused by a limited bandwidth and consequently, achieve higher accuracy compared with the existing TR localization approach
Effects of Jet Path on Electrospun Polystyrene Fibers
In this study we investigated the effects of jet path on the morphology and mat size of synthetic polystyrene (PS) fibers during the electrospinning process. In addition, the mechanism of the fiber mats, which were prepared by varying the solution concentration, was evaluated. The straight jet length, envelope cone and whipping frequency of each electrospun jet were studied using images captured by a high-speed photography camera. The results showed that higher solution concentrations led to longer straight jet lengths, smaller envelope cones and lower whipping frequencies. The diameter and surface morphology of the PS fibers were also characterized by scanning electron microscopy (SEM). It was found that fibers spun with higher solution concentrations exhibited larger diameters and diameter distributions because of their jet path features. Furthermore, the electrospun jets with higher concentrations increased elongation and produced smaller fiber mats and higher breaking forces as a result of their different jet paths, which was a consequence of varying the solution concentration
Synergistic Effects of 1-Octyl-3-Methylimidazolium Hexafluorophosphate and Cellulose Nanocrystals on Improving Polyacrylate Waterborne Anti-Corrosion Coatings
In this study, three copolymers of poly(methyl methacrylate) and poly(butyl acrylate) (PMMA-co-PBA) latex containing 1-octyl-3 methylimidazolium hexafluorophosphate (C8mimPF6), cellulose nanocrystals (CNCs), and C8mimPF6-CNCs were successfully synthesized through mini emulsion polymerization. These novel composites were each coated on mild steel panels and tested for their anti-corrosion performance by immersion of the coated samples in 3.5 wt% sodium chloride (NaCl) solution over a certain period. The synergistic anti-corrosion effects of the C8mimPF6-CNCs sample led to the highest coating resistance, charge transfer resistance, and corrosion inhibition efficiency and the lowest diffusion coefficient and corrosion rate. The proposed synergistic mechanism revealed that CNCs enhanced the barrier effect of the coating while C8mimPF6 inhibited corrosion when released
Control of Anatase TiO2 Nanocrystals with a Series of High-Energy Crystal Facets via a Fuorine-Free Strategy
National Basic Research Program of China [2011CBA00508]; National Natural Science Foundation of China [21131005, 21021061, 21073145]; Key Scientific Project of Fujian Province of China [2009HZ0002-1]; Priority Academic Program Development of Jiangsu Higher Education Institution