Search

• The problem of overdetermined system of time-varying linear equations is firstly solved with the sixth-order approximation. • Theoretical analysis and experiments are provided to validate the availability and superiority of the proposed algorithm. • Applications of mobile localization are provided to show the applicability and effectiveness of the proposed algorithm. • The proposed algorithm is indicated to be useful for mobile localization of high precision. The challenges of the inefficiency of the existing static least-squares method and the insufficient precision of the existing neural algorithms need to be overcome. With the aid of the ten-instant Zhang time discretization formula, a novel ten-instant discrete-time neural network algorithm is proposed and generalized to the problem-solving of overdetermined system of time-varying linear equations. Theoretical analyses illustrate that the maximal steady-state residual error of the proposed algorithm has an order-6 pattern. Comparative experiment results further substantiate the superiority of the proposed algorithm. Moreover, applications of mobile localization based on the angle of arrival technique and the time difference of arrival technique are provided to display the applicability of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Time-variant Yang-Baxter-like matrix equation (YBLME) with the disturbances of noises is the hotspot in various scientific disciplines. The existing research, either can not handle the noise, or rely on the build-in numerical algorithm provided by MATLAB. Therefore, it is necessary to further study the digital-computer discrete solution of this problem. In this paper, the authors propose a noise-handling ten-instant discrete solution for the time-variant YBLME. By defining the matrix-form error function, Zhang neural network (ZNN) is exploited to design the continuous-time noise-handling ZNN model. For potential digital hardware (i.e., digital computer) realization, a discrete-time ZNN-based noise-handling ten-instant (DTZNH10i) algorithm, which is capable of handling three types of noises, is proposed on the basis of a Zhang time discretization (ZTD) formula. The convergence and precision of the proposed DTZNH10i algorithm are investigated and discussed. Theoretical analyses show the correctness and effectiveness of the proposed algorithm. The paper offers three examples of time-variant YBLME with disturbances of constant, linear, and bounded random noises to illustrate the efficacy and convergence of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Image-text matching is a vital yet challenging task in the field of vision and language. Unlike previous methods that usually adopt a symmetrical network to independently embed images and sentences into a joint latent space, we propose a novel Global-guided Asymmetric Attention Network (GAAN) to represent the two modalities more comprehensively. Specifically, we first design a Global Information-guided Transformer Encoder (GITE) to effectively mitigate the drawback of the lack of contextual information of the region features. Taking full advantage of the image global information, GITE is able to model the regional relations and region-global relations simultaneously, so as to obtain a more accurate visual representation. Then, we adopt a Textual Self-Attention (TSA) module to explore the word-word relations and produce the context-aware word representations. Finally, we deploy an Image-guided Textual Attention (ITA) module to explore the fine-grained correspondence between image regions and sentence words. By using context-aware visual information to guide textual representation learning, we can build asymmetric connections between vision and language to better exploit textual information. Experimental results on two benchmark datasets including MSCOCO and Flickr30k show that GAAN significantly surpasses state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Dissolved oxygen (DO) in the electrolyte of aqueous zinc ion batteries (AZIBs) can cause irreversible side reactions in zinc metal anode. Therefore, the accurate detection of the DO concentration in the aqueous electrolyte is crucial for the performance promotion and mechanistic studies of AZIBs. Herein, organic electrochemical transistor (OECT) based DO sensors are developed by utilizing a carbon fiber (CF) derived CF/platinum/Nafion/polydimethylsiloxane composite as the gate electrode and amine-doped poly(3,4-ethylenedioxythiophene): polystyrene sulfonate as the channel semiconductor. Operating at a gate-source voltage of −0.1 V and a drain-source voltage of −0.025 V, the OECT-DO sensor demonstrates a high sensitivity (141 mV decade−1), a low detection limit (0.0011 mg L−1), a wide linear range (0.027–8.7 mg L−1), and good stability, which are attributed to the transconductance capability of OECT. The exceptional performance of the OECT-DO sensor enables the accurate monitoring of DO content in aqueous zinc sulfate electrolyte, which provides an opportunity to gain an insight of the impact of DO concentration on the zinc metal electrode. This study not only provides a cost-effective and efficient solution for detecting DO concentration in aqueous electrolytes, but also explores the potential applications of OECT sensors in the energy storage devices. • OECT sensor for detecting dissolved oxygen (DO) in aqueous electrolyte was fabricated for the first time. • The transconductance capability of OECT-DO effectively improved its DO sensing performances. • OECT-DO showed high sensitivity, low detection limit, wide linear range, and good stability. • The influence of DO in aqueous electrolyte on zinc-ion battery was studied with OECT-DO. [ABSTRACT FROM AUTHOR]

Two‒dimensional polymeric carbon nitride (2DPCN) is a versatile support for constructing single atom catalysts (SACs). Herein, we demonstrated a facile strategy for constructing atomic Co sites on 2DPCN. Atomic dispersion of Co was confirmed by the aberration‒corrected high angle annular dark field scanning transmission electron microscopy, while the extended X‒ray absorption fine structure spectroscopy analysis precisely corroborated the existence of atomic Co1–N 4 non square planar sites on 2DPCN support. Remarkably, Co1/2DPCN catalyst yielded H 2 at a rate of 28.3mmol H2 h−1 g Co −1, which is approximately 4.2 times higher than that of CoNPs/2DPCN (6.8mmol H2 h−1g Co −1) counterpart. Notably, with 0.75 wt % Pt as a co‒catalyst, H 2 evolution activity for Co1/2DPCN and CoNPs/2DPCN reached as high as 138.6 mmol H2 h−1 g metal −1 and 22.4mmol H2 h−1 g metal −1, respectively, which could be attributed to the synergistic effect of atomic Co1–N 4 sites and Pt. Both DFT calculations and spectroscopic results revealed that as constructed atomic Co1–N 4 sites, reduced band gap energy, improved light harvesting ability and decreased energy barrier for H 2 evolution. [Display omitted] • Demonstrated facile synthesis of Co single atoms on 2D polymeric carbon nitride support (Co1/2DPCN). • XAS analysis revealed the presence of distinct non square planar Co–N 4 atomic sites. • Atomic Co–N 4 sites promoted light absorption and directional charge transfer. • The atomic Co1/2DPCN catalyst achieved 28.3mmol H2 h−1 g Co −1 activity without the assistant of noble metal co‒catalyst. • Proposed H 2 evolution mechanism on the basis of experimental results and DFT calculations. [ABSTRACT FROM AUTHOR]

• Two ionic cuprous complexes with thermally activated delayed fluorescence were synthesized. • Both complexes exhibit high contributions of TADF (83 and 80%, respectively) and PLQYs (47.5 and 60.5%, respectively) in the solid state at ambient temperature. • The small exchange energy caused by the pronounced spatial separation between HOMOs and LUMOs leads to a small Δ E ST and TADF at ambient temperature. • The OLEDs based on both complexes exhibit good performance and very mild efficiency roll-off. Herein two novel ionic cuprous complexes [Cu(POP)(Pytzb)]BF 4 (Cu1 , POP = bis(2-diphenylphosphinophenyl)ether, Pytzb = 2-(1-(benzyl)-1H-1,2,3-triazol-4-yl)pyridine) and [Cu(Xantphos)(Pytzb)]BF 4 (Cu2 , Xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) have been synthesized in reasonable yields, and their crystal structure, UV absorption and photoluminescent properties, as well as electrochemical behaviors were investigated. At 300 K, both Cu1 and Cu2 in solid state exhibit outstanding green luminescence peaked at 533 and 526 nm, respectively, with significantly high photoluminescent quantum yields (PLQYs, 47.5 and 60.5%, respectively). Detailed exploration of emission decay times for Cu1 and Cu2 in dependence of temperature demonstrates that the two complexes are typical thermally activated delayed fluorescence (TADF) materials at ambient temperature with TADF proportions of 83 and 80%, respectively. The two complexes were employed as dopants in solution-processed electroluminescent devices. Thermally activated delayed fluorescence (TADF) of two new ionic cuprous complexes bearing 1,2,3-triazole ligand has been realized. Especially, both complexes exhibit high contributions of TADF (83 and 80%, respectively) and PLQYs (47.5 and 60.5%, respectively) in the solid state at ambient temperature. [Display omitted] [ABSTRACT FROM AUTHOR]

Excessive price and scarcity of Pt species make it very necessary to enhance the atom utilization and catalytic efficiency of Pt catalysts for implementing their industrial practicality. Here, natural cotton is adopted as the precursor to in-situ support well-dispersed and uniform-sized Ni nanoparticles, which then work as nanoislands to effectively deposit single-atom Pt via the galvanic replacement reaction. On the resulting fibrous carbon matrix, the monocrystalline Ni particles are verified to tightly anchor isolated Pt atoms to form the alloyed PtNi nanoparticles. In the 4-nitrophenol (4-NP) reduction to 4-aminophenol (4-AP), the catalytic activity of the bimetallic PtNi/C catalyst with the low Pt loading (0.81%) maximally reaches 25 times as high as the primary Ni/C product. Simulated calculations demonstrate that the single-atom Pt centers on PtNi nanoparticles rapidly capture and split H 2 molecules, while Ni atoms strongly adsorb 4-NP molecule to activate the -NO 2 group. Therefore, the trapped H atom could easily attack the -NO 2 and reduce 4-NP. Cotton is utilized to in-situ prepare well-dispersed and uniform-sized PtNi/C bimetallic catalysts with the superior activity in the 4-nitrophenol reduction. [Display omitted] • Natural cotton has been utilized for fabricating the Ni/C catalyst. • Ni nanoparticles work as nanoislands to deposit single-Atom Pt, forming PtNi nanoparticles. • The PtNi/C catalyst exhibits a great catalytic performance for reduction of 4-NP. • Catalytic mechanism of the PtNi/C bimetallic catalyst has been explored. [ABSTRACT FROM AUTHOR]