Stochastic resonance (SR), as a type of noise-assisted signal processing method, has been widely applied in weak signal detection and mechanical weak fault diagnosis. In order to further improve the ...weak signal detection performance of SR-based approaches and realize high-performance weak fault diagnosis, a global parameter optimization (GPO) model of a cascaded SR system is proposed in this work. The cascaded SR systems, which involve multiple multi-parameter-adjusting SR systems with both bistable and tri-stable potential functions, are first introduced. The fixed-parameter optimization (FPO) model and the GPO models of the cascaded systems to achieve optimal SR outputs are proposed based on the particle swarm optimization (PSO) algorithm. Simulated results show that the GPO model is capable of achieving a better SR output compared to the FPO model with rather good robustness and stability in detecting low signal-to-noise ratio (SNR) weak signals, and the tri-stable cascaded SR system has a better weak signal detection performance compared to the bistable cascaded SR system. Furthermore, the weak fault diagnosis approach based on the GPO model of the tri-stable cascaded system is proposed, and two rolling bearing weak fault diagnosis experiments are performed, thus verifying the effectiveness of the proposed approach in high-performance adaptive weak fault diagnosis.
Group‐IV monochalcogenide ferroelectric materials possess fascinating nonlinear optical properties and electro‐optical effects which play a vital role in 2D ferroelectrics, multiferroics and ...nonlinear optoelectronics. However, the studies of nonlinear optical properties of group‐IV monochalcogenides are still in their infancy stage. Herein, the preparation of few‐layer SnS by the molecular beam epitaxy (MBE) method is reported and the efficient second harmonic generation (SHG) of SnS monochalcogenide is systematically scrutinized by using ultrafast nonlinear optical spectroscopy. The obtained thickness‐dependent SHG is highly related with the coherence length. Second‐order nonlinear susceptibility of few‐layer SnS is also obtained. Polarization‐dependent SHG studies reveal its intrinsic anisotropy pattern and can be utilized to identify the crystalline orientation of few‐layer SnS film.
High quality few‐layer SnS is successfully prepared by molecular beam epitaxy. Efficient second harmonic generation (SHG) of the few‐layer SnS is systematically investigated. SHG anisotropy study is applied to determine the crystalline orientation of group‐IV monochalcogenides.
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The process safety and sustainable development of the petrochemical industry have been seriously threatened by the spontaneous combustion of iron sulfide. In this paper, four kinds of ...ionic liquids were used to study the inhibition of spontaneous combustion of iron sulfides (FeS, FeS2). The thermodynamic characteristics, inhibition performance, and mechanism of ionic liquids on the spontaneous combustion of iron sulfide have been systematically studied. The results showed that the iron sulfide samples’ overall surface roughness and the proportion of fine particles in the samples increased after the ionic liquid treatment. In the process of oxidative spontaneous combustion, the extrapolation reaction onset temperatures of the samples treated with ionic liquids were enhanced, and the temperature at the samples’ maximum mass loss rate also was delayed. At the same time, the effect of ionic liquids in this process also changed the samples’ reaction mechanism functions, the apparent activation energies, and the mass loss rate. And in all of the experiments, the apparent activation energy of the samples treated with BMIMNO3 was enhanced the most by 16.74 kJ/mol, 14.8 kJ/mol, 26.49 kJ/mol, 14.23 kJ/mol, and 13.87 kJ/mol, respectively, while the mass loss rate of the samples treated with this ionic liquid also decreased the most. Therefore, BMIMNO3 had the best inhibiting effect among the four ionic liquids in this study. In addition, the results of molecular simulations showed that there is an adsorption process between the ionic liquid and the iron sulfide. In the adsorption process, the ionic liquid dominated the adsorption competition with oxygen molecules, which raises the iron sulfide’s activation energy of the oxidation reaction, thus inhibiting spontaneous combustion.
AIoT applications often encounter challenges such as terminal resource constraints, data drift, and data heterogeneity in real world, leading to problems such as catastrophic forgetting, low ...generalization ability, and low accuracy during model training. To address these challenges, we proposed CoLLaRS, a cloud–edge–terminal collaborative lifelong learning framework for AIoT applications. In the CoLLaRS framework, we alleviate the problem of terminal resource constraints by uploading terminal tasks at the edge. CoLLaRS uses continuous training at the edge to achieve lifelong learning training of the model and solve the problem of catastrophic forgetting. CoLLaRS employs federated optimization in the cloud to perform personalized aggregation of different edge models and solve the problem of weak model generalization ability. Finally, the model is fine-tuned at the terminal to further optimize its accuracy in local tasks. Our experiments on real-world datasets showed that CoLLaRS has an 8% improvement in accuracy and a 5% improvement in backward transfer(BWT) and forward transfer(FWT) compared to other baseline algorithms. The results of the ablation experiments further confirmed the effectiveness of CoLLaRS.
•A cloud–edge–terminal collaborative lifelong learning framework.•Higher accuracy and robust to catastrophic forgetting with similar training time.•Evaluated in real-world AIoT semantic segmentation datasets.
Soot nanoparticles (SNPs) produced from incomplete combustion have strong impacts on aquatic environments as they eventually reach surface water, where their environmental fate and transport are ...largely controlled by aggregation. This study investigated the aggregation kinetics of SNPs in the presence of macromolecules including fulvic acid (FA), humic acid (HA), alginate polysaccharide, and bovine serum albumin (BSA, protein) under various environmentally relevant solution conditions. Our results showed that increasing salt concentrations induced SNP aggregation by suppressing electrostatic repulsion and that CaCl2 exhibited stronger effect than NaCl in charge neutralization, which is in agreement with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The aggregation rates of SNPs were variously reduced by macromolecules, and such stabilization effect was the greatest by BSA, followed by HA, alginate, and FA. Steric repulsion resulting from macromolecules adsorbed on SNP surfaces was mainly responsible for enhancing SNP stability. Such steric repulsion appeared to be affected by macromolecular structure, as BSA having a more compact globular structure on SNP surfaces imparted long-range steric repulsive forces and retarded the SNP aggregation rate by 10–100 times. In addition, alginate was shown to enhance SNP aggregation by ∼10 times at high CaCl2 concentrations due to alginate gel formation via calcium bridging. The results may bear strong significance for the fate and transport of SNPs in both natural and controlled environmental systems.
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•Stabilization of SNPs by macromolecules follows the order of BSA > HA > alginate > FA.•SNP stabilization occurs via macromolecule adsorption that imparts steric repulsion.•Adsorption affinity and structure of macromolecules affect stabilization of SNPs.•BSA adsorbed on SNPs retards aggregation by 10–100 times due to long-range repulsion.•Alginate gel formed by calcium bridging with Ca2+ enhances aggregation by ∼10 times.
Aggregation kinetics of SNPs in aquatic environments are significantly affected by environmental and biological macromolecules including FA, HA, alginate, and BSA.
Alkenyl oxindoles have been characterized as autophagosome-tethering compounds (ATTECs), which can target mutant huntingtin protein (mHTT) for lysosomal degradation. In order to expand the ...application of alkenyl oxindoles for targeted protein degradation, we designed and synthesized a series of heterobifunctional compounds by conjugating different alkenyl oxindoles with bromodomain-containing protein 4 (BRD4) inhibitor JQ1. Through structure-activity relationship study, we successfully developed JQ1-alkenyl oxindole conjugates that potently degrade BRD4. Unexpectedly, we found that these molecules degrade BRD4 through the ubiquitin-proteasome system, rather than the autophagy-lysosomal pathway. Using pooled CRISPR interference (CRISPRi) screening, we revealed that JQ1-alkenyl oxindole conjugates recruit the E3 ubiquitin ligase complex CRL4DCAF11 for substrate degradation. Furthermore, we validated the most potent heterobifunctional molecule HL435 as a promising drug-like lead compound to exert antitumor activity both in vitro and in a mouse xenograft tumor model. Our research provides new employable proteolysis targeting chimera (PROTAC) moieties for targeted protein degradation, providing new possibilities for drug discovery.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Sodium‐ion batteries (SIBs) based on solid‐state electrolytes (SSEs), although safe for high temperatures, are less capable of transferring ions at ambient temperatures, let alone at low ...temperatures. This work offers a simple and scalable technique to construct a nanofiber matrix composite electrolyte with boosting Na+ transport and interfacial compatibility for SIBs. Benefitting from the salt dissociation and selective cation conduction synergistic effect of the acylamino, carbonyl, and ester groups in the low‐cost copolymer synthesized from 2‐(methacryloyloxy)ethyl acetoacetate and N,N′‐methylenebisacrylamide, a facilitating of Na+ transport at extreme temperatures is realized. Besides, flexible flame retardance ceramic SiO2 nanofibers greatly enhance high‐temperature safety. The ultrathin functional AlF3 layer generated by binder‐free magnetron sputtering suppresses the dendrites, eliminating the interfacial issues between the electrolyte and anode, which is proved by 5500 h of ultrasteady plating/stripping. Superior ionic conductivity of 0.153 mS cm−1 at −30 °C implies fast Na+ transport, which is further evidenced by molecular dynamics simulations. Rate performance at 0.05–10 C from −30 to 130 °C further demonstrates the excellent electrochemical performance of the electrolyte. This work provides encouraging guidance for high‐safety SSEs with rapid Na+ conduction for SIBs operating at extra‐wide temperatures.
A rigid‐soft coupled nanofiber matrix composite electrolyte with salt dissociation and selective cation transport boosting is constructed by an in situ UV curing method. The flexible electrolyte exhibits low‐temperature adaptability and high‐temperature safety properties. What is more, the ultrathin binder‐free AlF3 layer on the electrolyte surface constructed by magnetron sputtering ensures a dendrite‐free anode.
Experiencing nature can induce the perception of happiness because of mental stress alleviation and well-being restoration. The largeness of green space may not always mean the frequency of ...experiencing greenery. It is arguing about the probability of positive sentiments in response to an experience of interacting with green nature. In this study, 38 green spaces were investigated in Nanchang City, China, where the green space area was evaluated by the largeness of the landscape metrics of the Normalized Vegetation Index (NDVI), and Green View Index (GVI) data were further obtained using Open Street Maps (OSM). The semantic segmentation method was used by machine learning to analyze a total of 1549 panoramic photos taken in field surveys to assess the Panoramic Green View Index (PGVI) proportion. The photos of 2400 people’s facial expressions were obtained from social networks at their check-in visits in green spaces and rated for happy and sad scores using FireFACE software. Split-plot analysis of variance suggested that different categories of NDVI largeness had a significant positive effect on posted positive sentiments. Multivariate linear regression indicated that PGVI was estimated to have a significant contribution to facial expression. Increasing the amount of PGVI promoted happy and PRI scores, while at the same time, neutral sentiments decreased with increasing PGVI. Overall, increasing the PGVI in green spaces, especially in parks with smaller green spaces, can be effective in promoting positive emotions in the visitor experience.
We investigated the adsorption mechanisms for removing fluoride based on experimental and modeling studies. Lanthanum-aluminum perovskite was designed for treating wastewater contaminated by ...fluoride. A fluorine-species model was developed to calculate the concentrations of different species of fluorine: F−, HF, HF2−. Multiple kinetic models were examined and the pseudo-second order model was found the best to fit the experimental data, implying fast-chemisorption. The thermodynamic data were fitted by the Langmuir model and Freundlich model at different temperatures, indicating heterogeneous adsorption at low temperature and homogeneous adsorption at high temperature. The La2Al4O9 material had less influence from negative ions when adsorbing fluoride. The adsorption mechanisms were further studied using experiments and Density Functional Theory calculations. The adsorption experiments could be attributed to the lattice plane (1 2 1) and La, O, Al sites. More Al sites were required than La sites for the increase of fluoride concentration. By contrast, more La sites than Al sites were needed for increased pH.
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•The hollow Lanthanum-aluminum perovskite was first applied to remove fluoride.•The species of F−, HF, HF2− played a more important role at different pH.•The Lanthanum sites had more important effect than Aluminum at higher pH.•Ηigher concentrations of fluoride required more Aluminum than Lanthanum sites.
Solar steam generation provides a renewable and environmentally friendly approach to solve the water shortage issue. The pursuit of efficient, stable, and cheap photothermal agents is thus of great ...significance. In this work, Cu nanoparticles (NPs) fabricated simply by a substitution reaction, exhibit a near-unity (∼97.7%) light absorption, covering a broad incident angle and wavelength range (200-1300 nm). Thereby, a high photothermal conversion efficiency of 93% is achieved. The excellent photothermal performance offers a unique opportunity for the development of solar steam generation. By coating the Cu NPs on a cellulose membrane, a solar steam generation efficiency up to 73% is acquired at a low irradiation power density of 2 kW m−2 (1 kW m−2 = 1 sun). Moreover, the Cu NPs are recyclable with the high stability being resistant to heat, photoirradiation and corrosion of brine.
