Aggregation‐induced emission (AIE) is an attractive phenomenon in which materials display strong luminescence in the aggregated solid states rather than in the conventional dissolved molecular ...states. However, highly luminescent inks based on AIE are hard to be obtained because of the difficulty in finely controlling the crystallinity of AIE materials at nanoscale. Herein, we report the preparation of highly luminescent inks via oil‐in‐water microemulsion induced aggregation of Cu–I hybrid clusters based on the highly soluble copper iodide‐tris(3‐methylphenyl)phosphine (Cu4I4(P‐(m‐Tol)3)4) hybrid. Furthermore, we can synthesize a series of AIE inks with different light‐emission colors to cover the whole visible spectrum range via a facile ligand exchange processes. The assemblies of Cu–I hybrid clusters with AIE characteristics will pave the way to fabricate low‐cost highly luminescent inks.
Ink‐lined to glow: Highly luminescent inks based on AIE Cu–I hybrids clusters are prepared by the self‐assembly of Cu–I hybrid cluster aggregates in microemulsion droplets. A subsequent ligand exchange step expands the color pallet of the as‐fabricated inks.
Although biomimetic designs are expected to play a key role in exploring future structural materials, facile fabrication of bulk biomimetic materials under ambient conditions remains a major ...challenge. Here, we describe a mesoscale "assembly-and-mineralization" approach inspired by the natural process in mollusks to fabricate bulk synthetic nacre that highly resembles both the chemical composition and the hierarchical structure of natural nacre. The millimeter-thick synthetic nacre consists of alternating organic layers and aragonite platelet layers (91 weight percent) and exhibits good ultimate strength and fracture toughness. This predesigned matrix-directed mineralization method represents a rational strategy for the preparation of robust composite materials with hierarchically ordered structures, where various constituents are adaptable, including brittle and heat-labile materials.
Artificial synapses are the key building blocks for low‐power neuromorphic computing that can go beyond the constraints of von Neumann architecture. In comparison with two‐terminal memristors and ...three‐terminal transistors with filament‐formation and charge‐trapping mechanisms, emerging electrolyte‐gated transistors (EGTs) have been demonstrated as a promising candidate for neuromorphic applications due to their prominent analog switching performance. Here, a novel graphdiyne (GDY)/MoS2‐based EGT is proposed, where an ion‐storage layer (GDY) is adopted to EGTs for the first time. Benefitting from this Li‐ion‐storage layer, the GDY/MoS2‐based EGT features a robust stability (variation < 1% for over 2000 cycles), an ultralow energy consumption (50 aJ µm−2), and long retention characteristics (>104 s). In addition, a quasi‐linear conductance update with low noise (1.3%), an ultrahigh Gmax/Gmin ratio (103), and an ultralow readout conductance (<10 nS) have been demonstrated by this device, enabling the implementation of the neuromorphic computing with near‐ideal accuracies. Moreover, the non‐volatile characteristics of the GDY/MoS2‐based EGT enable it to demonstrate logic‐in‐memory functions, which can execute logic processing and store logic results in a single device. These results highlight the potential of the GDY/MoS2‐based EGT for next‐generation low‐power electronics beyond von Neumann architecture.
A novel graphdiyne (GDY)/MoS2‐based electrolyte‐gated transistor using GDY as a Li‐ion‐storage layer is proposed, which features robust stability and flexibility, an ultralow energy consumption, a long retention time, a quasi‐linear weight update with low noise, an ultrahigh Gmax/Gmin ratio, and an ultralow readout conductance. This GDY/MoS2‐based EGT has demonstrated its potential in applications of neuromorphic computing and in‐memory computing.
The exploration of lead‐free halide perovskite nanocrystals (NCs) with intriguing optical properties is highly desirable owing to the toxicity and instability of lead halide perovskite NCs. Here, a ...new kind of uniform lead‐free double perovskite Cs2NaBiCl6 NCs are reported as versatile hosts to accommodate ionic dopants for improving optical properties especially the photoluminescence (PL). In contrast to the low deep‐blue PL with a quantum yield of only 1.7% of the as‐synthesized pristine Cs2NaBiCl6 NCs, the PL of the Cs2NaBiCl6 NCs can be impressively regulated and enhanced via doping Ag+, Mn2+, or Eu3+ ions in the double perovskite lattices. The femtosecond time‐resolved transient absorption spectroscopy is adopted to unravel the PL enhancement mechanism of the ion doping in the Cs2NaBiCl6 NCs. For the Ag+‐doping, the excitonic absorption energy of the Cs2NaBiCl6 NCs can be tuned from 3.82 to 3.48 eV with the significant improvement of the PL quantum yield (PLQY) from 1.7% to 20%. The Mn2+‐doped Cs2NaBiCl6 NCs show broad orange–red emission peak centered at 585 nm with a PLQY of 3%, owing to the 4T1→6A1 transition of octahedrally coordinated Mn2+. Eu3+‐doped Cs2NaBiCl6 NCs are endowed with strong Eu3+5D0→7FJ (J = 1, 2) orange–red emission at 591 and 615 nm.
A series of ions (Ag+, Mn2+, and Eu3+) doped lead‐free double perovskite Cs2NaBiCl6 nanocrystals (NCs) with uniform morphologies and good air stability are synthesized, exhibiting impressively enhanced photoluminescence in comparison to pristine Cs2NaBiCl6 NCs. The ion doping mechanisms for improving the PL are unraveled by the femtosecond time‐resolved transient absorption spectroscopy characterizations as well.
Plants of the genus Taxus have attracted much attention owing to the natural product taxol, a successful anti-cancer drug. T. fuana and T. yunnanensis are two endangered Taxus species mainly ...distributed in the Himalayas. In our study, an untargeted metabolomics approach integrated with a targeted UPLC-MS/MS method was applied to examine the metabolic variations between these two Taxus species growing in different environments.
The level of taxol in T. yunnanensis is much higher than that in T. fuana, indicating a higher economic value of T. yunnanensis for taxol production. A series of specific metabolites, including precursors, intermediates, competitors of taxol, were identified. All the identified intermediates are predominantly accumulated in T. yunnanensis than T. fuana, giving a reasonable explanation for the higher accumulation of taxol in T. yunnanensis. Taxusin and its analogues are highly accumulated in T. fuana, which may consume limited intermediates and block the metabolic flow towards taxol. The contents of total flavonoids and a majority of tested individual flavonoids are significantly accumulated in T. fuana than T. yunnanensis, indicating a stronger environmental adaptiveness of T. fuana.
Systemic metabolic profiling may provide valuable information for the comprehensive industrial utilization of the germplasm resources of these two endangered Taxus species growing in different environments.
This study takes the Yangtze River Economic Belt as a study area and analyzes the impacts of natural and socioeconomic factors on air pollution based on a dataset of urban air quality monitoring data ...in 2015 and meteorological and economic statistical data. We first apply the grey relational degree to test for the quantitative relationships between the natural and socioeconomic factors and air pollution. We then employ a novel method, specifically, the geographical detector, from the perspective of spatial stratified heterogeneity to reveal the potential impacts and interaction impacts of the natural and socioeconomic factors on air pollution. The results are as follows. (1) The grey relational degree results reveal that all factors in the topographical and meteorological layer, pollution sources layer, economic development layer, and urbanization layer have high relational degrees, indicating that these factors are closely correlated with air pollution. (2) The factor detector analysis reveals that the PM2.5 factor has the biggest q value, indicating that it is the primary contributor to air pollution, followed by PM10 and elevation. (3) The interaction detector analysis reveals that the interaction of two factors plays a more important role in influencing air pollution than does each factor individually. Moreover, the interactions between pair factors of pollution sources are the strongest. (4) The risk detector analysis reveals that elevation and precipitation are negatively correlated with air pollution, whereas pollution and urbanization factors are positively correlated with air pollution. (5) Finally, two leading impact areas for atmospheric pollution, namely, the Yangtze River Delta urban agglomeration and the Wuhan metropolitan area are predominantly attributed to the combination of natural and urbanization factors, whereas Yunnan and Guizhou are the least impact areas for atmospheric pollution because of their topographical and meteorological factors.
•The relations between air pollution and natural and economic factors are found.•The novel geographical detector method is applied in this study.•PM2.5 factor has the biggest q value, implying the primary pollutant.•Interaction of factors plays a more important role in affecting air pollution.
Fabricating a robust interfacial layer on the lithium metal anode to isolate it from liquid electrolyte is vital to restrain the rapid degradation of a lithium metal battery. Here, we report that the ...solution-processed metal chloride perovskite thin film can be coated onto the lithium metal surface as a robust interfacial layer to shield the lithium metal from liquid electrolyte. Via phase analysis and density functional theory calculations, we demonstrate that the perovskite layer can allow fast lithium ion shuttle under a low energy barrier of 0.45 eV without the collapse of framework. Such perovskite modification can realize stable cycling of LiCoO
|Li cells with an areal capacity of 2.8 mAh cm
using thin lithium metal foil (50 μm) and limited electrolyte (20 μl mAh
) for over 100 cycles at 0.5 C. The metal chloride perovskite protection strategy could open a promising avenue for advanced lithium metal batteries.
The classification of electrocardiogram (ECG) signals is very important for the automatic diagnosis of heart disease. Traditionally, it is divided into two steps, including the step of feature ...extraction and the step of pattern classification. Owing to recent advances in artificial intelligence, it has been demonstrated that deep neural network, which trained on a huge amount of data, can carry out the task of feature extraction directly from the data and recognize cardiac arrhythmias better than professional cardiologists. This paper proposes an ECG arrhythmia classification method using two-dimensional (2D) deep convolutional neural network (CNN). The time domain signals of ECG, belonging to five heart beat types including normal beat (NOR), left bundle branch block beat (LBB), right bundle branch block beat (RBB), premature ventricular contraction beat (PVC), and atrial premature contraction beat (APC), were first transformed into time-frequency spectrograms by short-time Fourier transform. Subsequently, the spectrograms of the five arrhythmia types were utilized as input to the 2D-CNN such that the ECG arrhythmia types were identified and classified finally. Using ECG recordings from the MIT-BIH arrhythmia database as the training and testing data, the classification results show that the proposed 2D-CNN model can reach an averaged accuracy of 99.00%. On the other hand, in order to achieve optimal classification performances, the model parameter optimization was investigated. It was found when the learning rate is 0.001 and the batch size parameter is 2500, the classifier achieved the highest accuracy and the lowest loss. We also compared the proposed 2D-CNN model with a conventional one-dimensional CNN model. Comparison results show that the 1D-CNN classifier can achieve an averaged accuracy of 90.93%. Therefore, it is validated that the proposed CNN classifier using ECG spectrograms as input can achieve improved classification accuracy without additional manual pre-processing of the ECG signals.
PDF
