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Cross-Channel Specific-Mutual Feature Transfer Learning for Motor Imagery EEG Signals Decoding.

In recent years, with the rapid development of deep learning, various deep learning frameworks have been widely used in brain-computer interface (BCI) research for decoding motor imagery (MI) electroencephalogram (EEG) signals to understand brain activity accurately. The electrodes, however, record the mixed activities of neurons. If different features are directly embedded in the same feature space, the specific and mutual features of different neuron regions are not considered, which will reduce the expression ability of the feature itself. We propose a cross-channel specific-mutual feature transfer learning (CCSM-FT) network model to solve this problem. The multibranch network extracts the specific and mutual features of brain's multiregion signals. Effective training tricks are used to maximize the distinction between the two kinds of features. Suitable training tricks can also improve the effectiveness of the algorithm compared with novel models. Finally, we transfer two kinds of features to explore the potential of mutual and specific features to enhance the expressive power of the feature and use the auxiliary set to improve identification performance. The experimental results show that the network has a better classification effect in the BCI Competition IV-2a and the HGD datasets.

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Three-parameter sensing characteristics of PCF based on surface plasmon resonance

In this study, a refractive index-temperature sensor based on surface plasmon resonance (SPR) in photonic crystal fiber (PCF) is proposed. Unlike conventional dual-parameter sensing research, this sensor features three sensing channels, offering the advantages of high-sensitivity measurements without cross-interference, utilizing three different plasmonic materials (Au, AZO, Ag), and enabling accurate measurement of temperature and refractive indices of two different analytes simultaneously. The finite element method is employed to investigate the influence of sensor structural parameters on sensing performance and optimize these parameters. In channel 1, analytes within the range of 1.37–1.43 can be detected, with maximum wavelength sensitivity (WS) of 31,500 nm/RIU and maximum amplitude sensitivity (AS) of 5690RIU−1. The range of the SPR sensor in CH-2 is 1.25–1.40, with a max WS value of 5500 nm/RIU and peak AS of 10,845RIU−1. Furthermore, the sensor obtains a higher figure of merit of 2357RIU−1 and a maximum wavelength resolution of 9.2208×10−7. Regarding temperature sensing, the proffered sensor has shown its ability to detect environmental temperature, with a wide detection range from 5°C to 95°C degrees and a maximum WS of 6.3 nm/°C. In summary, the proposed PCF-SPR sensor is capable of precise measurement of solution concentration and environmental temperature over a wide range, exhibiting high sensitivity and possessing potential applications in biosensing, environmental temperature detection, and more.

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Characteristics study of a dual-wavelength polarization filter based on gold-filled square lattice photonic crystal fiber

This study proposes a polarization filter based on gold-filled photonic crystal fiber (PCF) with a square lattice structure. Utilizing the finite element method (FEM), the filtering characteristics of the model were numerically simulated. The dispersion relation and loss characteristics of this structure were analyzed, and the optimal structural parameters were obtained through structural adjustments. Furthermore, the performance of the filter was evaluated under a 2% variation in manufacturing tolerances for gold film thickness (), air hole spacing (), and air hole diameters () and (). Results indicated that at the 1310 nm and 1550 nm communication windows, the confinement losses of the filter were 1354.6 dB/cm and 869.04 dB/cm, respectively, while the losses for the -polarization were merely 16.97 dB/cm and 0.98 dB/cm. When the filter length was set to 0.5 mm, the maximum extinction ratios (ERs) for the two windows reached 588.2 dB and 370.6 dB, and the filter bandwidth extended to 640 nm. Moreover, the characteristics of the filter under manufacturing tolerances were computed, revealing that the filter’s performance remained stable and feasible despite manufacturing errors. The proposed rectangular gold-coated PCF is anticipated to have broad applications in optical fiber communication and optical information processing.

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Preparation of electrocatalytic KC-GR/GF membrane cathode and its application in electro-Fenton

ABSTRACT Tetracycline is a common antibiotic that threatens the water environment and requires more stable and efficient ways to degrade it. In this paper, a novel filtered cathode material was prepared by proportionally loading Ketjen Black Carbon (KC) and Graphene (GR) onto Graphite Felt(GF) by coating method, and applied to remove tetracycline from water by electro-Fenton system. The results showed that the highest hydrogen peroxide yield of up to 28.86 mg/L was achieved at the electrodes prepared with a carbon loading of 0.228 g, m (KC):m(polytetrafluoroethylene) = 1:9, and m (KC):m (GR) = 2:2. By characterisation, the contact angle of the loaded graphite felt electrode increased from 71.5° to 126.3°, with faster current responsiveness and larger electrochemically active area than the unloaded electrode. Furthermore, in the application of electro-Fenton: when I = 100 mA, Air = 0.45 L/min, pH = 3 and Fe2+ = 0.3 mol/L, the optimal removal rate of 50 mg/L tetracycline was 99.1%, and the energy consumption was only 8.49 kWh/kg. This electrode has a great advantage in treating the low concentration of tetracycline, and 99.4% of tetracycline can be removed within 30 min. After 8 cycles of tests, the removal rate of tetracycline by this electrode was above 95%. The article demonstrated that the reactor coupled with electrochemical advanced oxidation technology and membrane filtration technology has the effect of enhanced mass transfer, and the Ketjen Black Carbon-Graphene/Graphite Felt (KC-GR/GF) electrocatalytic membrane cathode has the potential and practical significance to be applied for the removal of tetracycline under the electro-Fenton system.

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The Design of a Novel Alkali-Activated Binder for Solidifying Silty Soft Clay and the Study of Its Solidification Mechanism.

In order to overcome the problems of the high economic and environmental costs of a traditional ordinary portland cement-based binder, this study used self-combusted coal gangue (SCCG), granulated blast furnace slag (GBFS) and phosphorous slag (PS) to prepare a novel SCCG-GBFS-PS (SGP) ternary alkali-activated binder for solidifying silty soft clay (SC). Firstly, the parameters of the SGP ternary binder were optimized using orthogonal experiments. Then the effects of the SGP ternary binder content (mass ratio of the SGP ternary binder and the SGP-solidified soil), initial water content of SC (mass ratio of SC' water and SC) and types of additives on the unconfined compressive strength (UCS) of the SGP-solidified soil were analyzed. Finally, the hydration products and microstructure of the SGP-solidified soil were analyzed to investigate the solidification mechanism of the SGP ternary binder. The results showed that the optimal mass ratio of GBFS and PS is 2:1, and the optimal alkali activator content (mass ratio of Na2O and the SGP ternary binder) and modulus of alkali activator (molar ratio of SiO2 and Na2O of alkali activator) were 13% and 1.3, respectively. When the SGP ternary binder content was 16% and the initial water content of SC was 35%, the SGP-solidified soil met the requirement of UCS for tertiary cured soil. The incorporation of triethanolamine and polyvinyl alcohol improved the UCS, while the incorporation of Na2SO4 significantly deteriorated the UCS of the SGP-solidified soil. The C-S-H gels and C(N)-A-S-H gels generated by hydration of the SGP-solidified soil were interspersed, interwoven and adhered to each other to form a network-like space structure that played the roles of skeleton, bonding soil particles and filling pores, which improved the macroscopic properties of the SGP-solidified soil. The results of this study provide a reference for the design and development of a solid waste-based binder for solidifying SC.

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Study on the Characteristics and Mechanism of Shield Tunnel Mud Cake Disintegration in Complex Red-Bed Geology

The complex red-bed geology is primarily composed of iron-rich sedimentary rock layers with clay minerals as a major component. The soil water content exceeds 30%, and its high viscosity and water content lead to the easy formation of mud cake on the cutterhead, endangering the safety and progress of construction, which poses a significant challenge for tunnel boring machines (TBMs). The use of dispersants to eliminate mud cake is a common method in engineering projects. This paper presents an improved disintegration experiment instrument to study the disintegration characteristics of mud cake from the red-bed geology under different dispersant solutions, proposing a dispersant formulation suitable for the red-bed geology of the Haizhu Bay Tunnel project. The results indicate that mud cake samples exhibit a moderate disintegration effect in pure water. Furthermore, it has been observed that the disintegration effect decreases as the thickness of mud cake increases. Sodium silicate solution was not suitable for treating the red-bed geological mud cake, while sodium hexametaphosphate and oxalic acid solutions had a good promoting effect on the disintegration of red-bed geological mud cake. However, there was a threshold for the dispersant concentration; exceeding this threshold actually worsened the disintegration effect. Ultimately, the engineering application of a 10% oxalic acid solution, which proved effective in disintegrating the mud cake, significantly enhanced the excavation efficiency in the Haizhu Bay Tunnel project.

Open Access
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