The discovery of highly active and cost-effective materials capable of catalyzing the oxygen evolution reaction (OER) is essential for water splitting. In the present study, we developed a new method ...for producing the structural components of advanced non-precious metal electrocatalysts NiS/CeS nanocomposite supported on stainless steel strip (SSS) represented as NiS/CeS/SSS that are both innovative and practical. To accomplish a current density of 10 mA cm
−2
, the NiS/CeS/SSS requires OER overpotential of 289 mV, which is smaller than the pure NiS/SSS (319 mV) and CeS/SSS (309 mV), and with enhanced stability of 40 h tested in 1.0 M KOH electrolyte. The higher efficiency of OER is due to the strong electrical contacts between NiS/SSS and CeS/SSS, the availability of active centers, and also the lower charge transfer resistance.
It is important to accurately classify the defects in hot rolled steel strip since the detection of defects in hot rolled steel strip is closely related to the quality of the final product. The lack ...of actual hot-rolled strip defect data sets currently limits further research on the classification of hot-rolled strip defects to some extent. In real production, the convolutional neural network (CNN)-based algorithm has some difficulties, for example, the algorithm is not particularly accurate in classifying some uncommon defects. Therefore, further research is needed on how to apply deep learning to the actual detection of defects on the surface of hot rolled steel strip. In this paper, we proposed a hot rolled steel strip defect dataset called Xsteel surface defect dataset (X-SDD) which contains seven typical types of hot rolled strip defects with a total of 1360 defect images. Compared with the six defect types of the commonly used NEU surface defect database (NEU-CLS), our proposed X-SDD contains more types. Then, we adopt the newly proposed RepVGG algorithm and combine it with the spatial attention (SA) mechanism to verify the effect on the X-SDD. Finally, we apply multiple algorithms to test on our proposed X-SDD to provide the corresponding benchmarks. The test results show that our algorithm achieves an accuracy of 95.10% on the testset, which exceeds other comparable algorithms by a large margin. Meanwhile, our algorithm achieves the best results in Macro-Precision, Macro-Recall and Macro-F1-score metrics.
Mainstream materials of the railway pantograph strips are carbon composites. They are subject to wear during use, as well as various types of damage. It is important that their operation time is as ...long as possible and that they are not damaged, as it may damage the remaining elements of the pantograph and the overhead contact line. As part of the article, three types of pantographs were tested: AKP-4E, 5ZL, and 150 DSA. They had carbon sliding strips made of MY7A2 material. By testing the same material on different types of current collectors, it was possible to check what impact the wear and damage of the sliding strips has on (among others) the method of their installation, i.e., whether the damage to the strips depends on the type of current collector and what is the participation of damage caused by material defects. As a result of the research, it was found that the type of pantograph on which it is used has an undoubted influence on the damage characteristics of the carbon sliding strips, whereas the damage caused by material defects can be classified as a more general group-the group of damage of a sliding strip, which also includes overburning of a carbon sliding strip.
A planar super-wideband (SWB) antenna fed by an asymmetric coplanar strip is proposed, fabricated, and tested. The antenna consists of a hexagonal loop strip in which a signal strip is prolonged, ...curved, and shorted to a ground plane to facilitate SWB characteristics. In addition, by adding a boomerang-shaped strip to the ground plane, the effective electrical length is increased, thereby decreasing the lowest operating frequency. The simulated results show that the proposed antenna exhibits a −10 dB reflection bandwidth from 1.18 to 49.22 GHz corresponding to a ratio bandwidth of 41.7:1. The measured results of the fabricated antenna are also represented and compared with the simulated results. The antenna gain changes from 2.05 to 10.62 dBi within the measured frequency range.
In this work, we present results of quantum detector tomography of superconducting single photon detector (SSPD) based on MoSi film, and compare them with previously reported data on NbN. We find ...that for both materials hot spot interaction length coincides with the strip width, and the dependence of single and double-spot detection efficiencies on bias current are compatible with sufficiently large hot-spot size, approaching the strip width.
•A quantitative ciprofloxacin (CIP) immunochromatographic test strip is designed.•It is very sensitive with an extremely low detection limit of 0.05 ng/mL.•It has wide linear detection range ...supporting quantitative CIP detection.•It supports automatic, rapid and cost-effective CIP detection.•It is proved with good selectivity, reproducibility and stability.
The ciprofloxacin (CIP) abuse has caused many problems threatening to human health. Here, we design the quantum dot microsphere (QDM) based immunochromatographic quantitative CIP test strip: when the sample under detection contains CIP, the QDM-monoclonal antibody (mAb) probes bound with the CIP and cannot be captured by CIP-bovine serum albumin (BSA) conjugation dispersed on the T lines, reducing the fluorescence intensities. These test strips can provide a low detection limit of 0.05 ng/mL and a wide linear detection range from 0.1 ng/mL to 100 ng/mL in high sensitivity and accuracy as well as good selectivity, reproducibility and stability. Moreover, a smartphone based test strip reader with the size of 85 mm × 48 mm × 44 mm is also fabricated using 3-D printing to automatically and quantitatively detect CIP. The whole process of CIP detection can be finished within 15 min, but only cost ~1 RMB (10 cents).
During the geomagnetic storm on 3–6 November 2021, the in‐situ plasma density and the gridded total electron content (TEC) maps registered a persistent presence of the strip‐like bulges (electron ...density enhancement, also known as the shoulders in previous literatures) at lower‐middle latitudes. The observed strip‐like bulge resided in the Pacific‐America‐Atlantic sector and lasted from 07:00 UT on 4 November to 20:00 UT on 6 November. For the first time, the temporal evolution of the 2‐D strip‐like bulge was recorded by gridded TEC maps, though observations were limited over the North American continents. The TEC maps showed a continuous shrinking of the nightside midlatitude plasma band structure right before the presence of the narrow strip‐like bulge. Simultaneous measurements from the Ionospheric Connection Explorer satellite (ICON) revealed an equatorward turning of the field‐aligned ion transportation driven by the disturbance equatorward neutral winds. However, the enhanced fountain effect at low latitudes was not observed during the entire formation phase of the strip‐like bulge. We propose that the storm‐induced enhanced equatorward thermospheric neutral winds push the plasma equatorward along the field lines, and the plasma band structure was developed into the strip‐like bulge. In addition, the ion composition of both the plasma band structure and the strip‐like bulges are dominated by H+, and the maintenance of the strip‐like bulge could be due to the compensation of the downward plasmaspheric content flux.
Key Points
The temporal evolution of the 2‐D strip‐like bulge is recorded on gridded total electron content (TEC) maps
The strip‐like bulge is a consequence of the narrowing midlatitude band structure driven by the disturbance neutral wind
The enhanced equatorial fountain effect is not involved during the formation of the strip‐like bulge
Acoustic black holes (ABHs) achieved by thinning structural thickness following a power-law profile have shown fantastic applications in vibration and noise suppression, energy harvesting, and wave ...manipulation. For the latter, many passband properties exemplified by self-collimation, focusing, and bi-refraction, have been reported on metamaterial plates with embedded circular ABHs in periodic arrangement. To date, however, band gaps (BGs), being the main feature for metamaterials, have not yet been observed in ABH plates. In this paper, we propose a new class of phononic crystal consisting in two crossed strip ABHs to open broad and complete BGs in plates, based on the dual benefit of local resonance and Bragg scattering effect. The dispersion curves of infinite strip ABHs are recovered by means of the Gaussian expansion method, then validated by a finite element model. The influences of ABH radius, ABH order and residual thickness, on the GBs have been carried out by parametric studies. The results show that the BGs can be modulated to very low frequencies via adjusting the ABH parameters, while maintaining the broadband characteristics. Finally, the wave propagation properties including isolation, guiding, and shielding, in plates with finite periodic arrays have been characterized, indicating that a small number of ABHs are very efficient to quarantine flexural waves. Experimental samples have been fabricated and tested, showing very close results compared to the BGs predicted by the GEM. Even though the proposed strip ABHs seems fragile in strength, peripheral frame can be adopted to partially alleviate this problem. The proposed PCs possess a great potential to broaden ABH applications in vibration control and wave manipulation in plates based on the highlighted BG feature.
Medium carbon steels have been widely used in the fields of tool and die manufacturing due to their outstanding hardness and wear resistance. In this study, microstructures of 50# steel strips ...fabricated by twin roll casting (TRC) and compact strip production (CSP) processes were analyzed to investigate the influences of solidification cooling rate, rolling reduction, and coiling temperature on composition segregation, decarburization, and pearlitic phase transformation. The results show that a partial decarburization layer with a thickness of 13.3 μm and banded C-Mn segregation were observed in the 50# steel produced by CSP, leading to the banded distributions of ferrite and pearlite in the C-Mn poor regions and C-Mn rich regions, respectively. For the steel fabricated by TRC, owing to the sub-rapid solidification cooling rate and short processing time at high temperatures, neither apparent C-Mn segregation nor decarburization was observed. In addition, the steel strip fabricated by TRC has higher pearlite volume fractions, larger pearlite nodule sizes, smaller pearlite colony sizes and interlamellar spacings due to the co-influence of larger prior austenite grain size and lower coiling temperatures. The alleviated segregation, eliminated decarburization and large volume fraction of pearlite render TRC a promising process for medium carbon steel production.
In this paper, a prediction model for hot-rolled strip crown based on an artificial neural network (ANN) is presented. Considering the mean squared error (MSE) and correlation coefficient (R), ...production data of 10,133 coils collected from a hot rolling plant are used to establish models. A feed-forward neural network with one hidden layer, a non-dominated sorting genetic algorithm II (NSGA II) optimized ANN, and a deep neural network (DNN) are applied to evaluate the prediction performance. Parameter settings of the ANN and NSGA II including learning rate, hidden neurons, activation function and population size, and crossover probability, are investigated to acquire the optimal model. The structure of the DNN, including how many layers and units the network should contain, is also studied. Prediction performance comparisons of the ANN, NSGA II-ANN, and DNN are presented. Among the ANN, NSGA II-ANN and DNN, the results show that the DNN has the highest prediction accuracy. Root mean squared error (RMSE) of the proposed DNN is 2. 06μm, and 97.04% of the prediction data have an absolute error of less than 5μm. Through model response surfaces, effects of four key operating parameters are investigated. The results indicate that the proposed DNN with strong learning ability and generalization performance can be well applied to hot rolling production.
•Three neural network based models are established based on a dataset from a hot-rolling line.•The proposed models used to predict strip crown can acquire high prediction precisions.•The best performed model precisely corresponds with the existing physical understandings.•Using the parameters obtained by the best performed model, strip crown is close to target values.
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