Data_Sheet_1_SGLFormer: Spiking Global-Local-Fusion Transformer with high performance.ZIP

IntroductionSpiking Neural Networks (SNNs), inspired by brain science, offer low energy consumption and high biological plausibility with their event-driven nature. However, the current SNNs are still suffering from insufficient performance.MethodsRecognizing the brain's adeptness at information processing for various scenarios with complex neuronal connections within and across regions, as well as specialized neuronal architectures for specific functions, we propose a Spiking Global-Local-Fusion Transformer (SGLFormer), that significantly improves the performance of SNNs. This novel architecture enables efficient information processing on both global and local scales, by integrating transformer and convolution structures in SNNs. In addition, we uncover the problem of inaccurate gradient backpropagation caused by Maxpooling in SNNs and address it by developing a new Maxpooling module. Furthermore, we adopt spatio-temporal block (STB) in the classification head instead of global average pooling, facilitating the aggregation of spatial and temporal features.ResultsSGLFormer demonstrates its superior performance on static datasets such as CIFAR10/CIFAR100, and ImageNet, as well as dynamic vision sensor (DVS) datasets including CIFAR10-DVS and DVS128-Gesture. Notably, on ImageNet, SGLFormer achieves a top-1 accuracy of 83.73% with 64 M parameters, outperforming the current SOTA directly trained SNNs by a margin of 6.66%.DiscussionWith its high performance, SGLFormer can support more computer vision tasks in the future. The codes for this study can be found in https://github.com/ZhangHanN1/SGLFormer.</p

Designing a Brightness-Restored Rhodamine Derivative by the Ortho-Compensation Effect for Assessing Drug-Induced Acute Kidney Injury

Effective monitoring of essential bioindicators with high-contrast fluorescence imaging is highly crucial to reveal the pathological progression of diseases. However, most reported probes based on asymmetric amino-rhodamine (ARh) derivatives are often limited in practical application due to the low signal-to-noise ratios. Herein, a new fluorophore, 3-methoxy-amino-rhodamine (3-MeOARh), with improved fluorescence quantum yield (0.51 in EtOH) is designed and synthesized by introducing methoxy group in the ortho-position of amino in asymmetric amino-rhodamine. Notably, the good properties of the ortho-compensation effect further effectively enable the construction of an activatable probe with a high signal-to-noise ratio. As a proof of concept, the probe (3-MeOARh-NTR) was successfully synthesized for nitroreductase detection with high selectivity, excellent sensitivity, and good stability. More importantly, the relationship between drug-induced kidney hypoxia and elevated nitroreductase concentration was first uncovered in living tissues through high-contrast imaging. Therefore, the study presents the activatable probe for kidney hypoxia imaging while highlighting the 3-MeOARh structure with a satisfactory signal-to-noise ratio. It is believed that 3-MeOARh can serve as an efficient platform for activatable probe construction to reveal the pathological progression of different diseases

Prediction and Experimental Validation Studies of Wet Flue Gas Desulphurization with a Novel Type PCF Device Based on Limestone-Gypsum

A novel wet-type flue gas desulphurization process were developed and tested in this study. The process used a PCF device as the absorber where SO₂ was absorbed into slurry of reactive CaCO₃. A model of external mass-transfer based on the two-film theory was proposed for estimation of the SO₂ absorption in the PCF device, and the theoretical SO₂ removal efficiency was compared with the experimental data. The results show that the SO₂ absorption rate in the spray zone is controlled by a combination of gas- and liquid-film diffusions in the range of tested operating conditions. The increase of gas flow rate and droplet size and decrease of liquid−gas ratio all can lead to a decrease in the SO₂ removal efficiency. Addition of Cl⁻ to the slurry (25 g/L) decreases the SO₂ removal efficiency from 83.87 to 70.75%. when comparing the results of prediction and experiment, the data show good agreement. With droplet size equal to 2500 μm, when gas flow rate and liquid−gas ratio are changed, the relative errors of SO₂ removal efficiency between the predicted and experimental data are below 3.40 and 8.67%, respectively. It demonstrates that the model proposed in the present study is an effective model to evaluate and predict the desulphurization performance of the novel type PCF device. Moreover, the theoretical model can be extended to apply in other wet FGD technologies

Lateral Growth of Composition Graded Atomic Layer MoS_{2(1–<i>x</i>)}Se_2<i>x</i> Nanosheets

Band gap engineering of transition-metal dichalcogenides is an important task for their applications in photonics, optoelectronics, and nanoelectronics. We report for the first time the continuous lateral growth of composition graded bilayer MoS_{2(1–<i>x</i>)}Se_2<i>x</i> alloys along single triangular nanosheets by an improved chemical vapor deposition approach. From the center to the edge of the nanosheet, the composition can be gradually tuned from <i>x</i> = 0 (pure MoS₂) to <i>x</i> = 0.68, leading to the corresponding bandgap being continuously modulated from 1.82 eV (680 nm) to 1.64 eV (755 nm). Local photoluminescence scanning from the center to the edge gives single band edge emission peaks, indicating high crystalline quality for the achieved alloy nanosheets, which was further demonstrated by the microstructure characterizations. These novel 2D structures offer an interesting system for probing the physical properties of layered materials and exploring new applications in functional nanoelectronic and optoelectronic devices

Giant second harmonic generation in supertwisted WS2 spirals grown in step edge particle induced non-Euclidean surfaces

In moir\'e crystals resulting from the stacking of twisted two-dimensional (2D) layered materials, a subtle adjustment in the twist angle surprisingly gives rise to a wide range of correlated optical and electrical properties. Herein, we report the synthesis of supertwisted WS2 spirals and the observation of giant second harmonic generation (SHG) in these spirals. Supertwisted WS2 spirals featuring different twist angles are synthesized on a Euclidean or step-edge particle-induced non-Euclidean surface using a carefully designed water-assisted chemical vapor deposition. We observed an oscillatory dependence of SHG intensity on layer number, attributed to atomically phase-matched nonlinear dipoles within layers of supertwisted spiral crystals where inversion symmetry is restored. Through an investigation into the twist angle evolution of SHG intensity, we discovered that the stacking model between layers plays a crucial role in determining the nonlinearity, and the SHG signals in supertwisted spirals exhibit enhancements by a factor of 2 to 136 when compared with the SHG of the single-layer structure. These findings provide an efficient method for the rational growth of 2D twisted structures and the implementation of twist angle adjustable endowing them great potential for exploring strong coupling correlation physics and applications in the field of twistronics

Mesoporous and Encapsulated In₂O₃/Ti₃C₂T_<i>x</i> Schottky Heterojunctions for Rapid and ppb-Level NO₂ Detection at Room Temperature

Rapid and ultrasensitive detection of toxic gases at room temperature is highly desired in health protection but presents grand challenges in the sensing materials reported so far. Here, we present a gas sensor based on novel zero dimensional (0D)/two dimensional (2D) indium oxide (In2O3)/titanium carbide (Ti3C2Tx) Schottky heterostructures with a high surface area and rich oxygen vacancies for parts per billion (ppb) level nitrogen dioxide (NO2) detection at room temperature. The In2O3/Ti3C2Tx gas sensor exhibits a fast response time (4 s), good response (193.45% to 250 ppb NO2), high selectivity, and excellent cycling stability. The rich surface oxygen vacancies play the role of active sites for the adsorption of NO2 molecules, and the Schottky junctions effectively adjust the charge-transfer behavior through the conduction tunnel in the sensing material. Furthermore, In2O3 nanoparticles almost fully cover the Ti3C2Tx nanosheets which can avoid the oxidation of Ti3C2Tx, thus contributing to the good cycling stability of the sensing materials. This work sheds light on the sensing mechanism of heterojunction nanostructures and provides an efficient pathway to construct high-performance gas sensors through the rational design of active sites

Controllable Growth and Formation Mechanisms of Dislocated WS₂ Spirals

Two-dimensional (2D) layered metal dichalcogenides can form spiral nanostructures by a screw-dislocation-driven mechanism, which leads to changes in crystal symmetry and layer stackings that introduce attractive physical properties different from their bulk and few-layer nanostructures. However, controllable growth of spirals is challenging and their growth mechanisms are poorly understood. Here, we report the controllable growth of WS₂ spiral nanoplates with different stackings by a vapor phase deposition route and investigate their formation mechanisms by combining atomic force microscopy with second harmonic generation imaging. Previously not observed “spiral arm” features could be explained as covered dislocation spiral steps, and the number of spiral arms correlates with the number of screw dislocations initiated at the bottom plane. The supersaturation-dependent growth can generate new screw dislocations from the existing layers, or even new layers templated by existing screw dislocations. Different number of dislocations and orientation of new layers result in distinct morphologies, different layer stackings, and more complex nanostructures, such as triangular spiral nanoplates with hexagonal spiral pattern on top. This work provides the understanding and control of dislocation-driven growth of 2D nanostructures. These spiral nanostructures offer diverse candidates for probing the physical properties of layered materials and exploring new applications in functional nanoelectronic and optoelectronic devices

Growth of Alloy MoS_2<i>x</i>Se_{2(1–<i>x</i>)} Nanosheets with Fully Tunable Chemical Compositions and Optical Properties

Band gap engineering of atomically thin two-dimensional layered materials is critical for their applications in nanoelectronics, optoelectronics, and photonics. Here we report, for the first time, a simple one-step chemical vapor deposition approach for the simultaneous growth of alloy MoS_2<i>x</i>Se_{2(1–<i>x</i>)} triangular nanosheets with complete composition tunability. Both the Raman and the photoluminescence studies show tunable optical properties consistent with composition of the alloy nanosheets. Importantly, all samples show a single bandedge emission peak, with the spectral peak position shifting from 668 nm (for pure MoS₂) to 795 nm (for pure MoSe₂), indicating the high quality for these complete composition alloy nanosheets. These band gap engineered 2D structures could open up an exciting opportunity for probing their fundamental physical properties in 2D and may find diverse applications in functional electronic/optoelectronic devices