While recent developments in electroencephalogram (EEG)-based brain-computer interfaces (BCIs) have enabled a bridge between the brain and external devices with relatively high communication speed, ...there is still room for improvement. Notably, the phenomenon of “BCI illiteracy,” which refers to the 15%–30% of people who struggle to type or control devices using BCI, remains unsolved, limiting the practical application of BCI systems. The EEG-based BCIs performance is constrained by the low-quality scalp EEG signals due to the attenuation and distortion of the skull. To address these limitations, this study proposes a hybrid BCI system combining EEG with magnetoencephalogram (MEG), a neuroimaging technology not influenced by the volume conduction effect, to boost BCI performance by enhancing signal quality. Comparative experiments involving 22 subjects showed that the steady-state visual evoked response (SSVER) from MEG has a wider range of effective bandwidth and higher signal-to-noise ratio than EEG. Moreover, differences in the spectral and spatiotemporal characteristics of MEG and EEG explain better performance. Simultaneous MEG-EEG recording experiments suggested that the hybrid MEG-EEG BCI achieved a significantly higher information transfer rate than either modality alone (hybrid: 312 ± 17 bits/min, MEG: 272 ± 17 bits/min, EEG: 240 ± 27 bits/min). Moreover, the 40-target classification accuracy of “BCI illiterate” increased from 50% to 95% with the help of MEG. These results highlight the methodological advantages of a hybrid MEG-EEG BCI, suggesting a promising paradigm for implementing high-speed BCIs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Core–shell nanocomposites of polyaniline and carbon black (PAni/CB) were electrochemically synthesized in acidic aniline and carbon black suspension. SEM and TEM observations reveal that the PAni ...synthesized in HClO
4 media exhibits one-dimensional (1D) growth and results in a porous PAni deposit constructed by coralloid interlinking branches having about 2
μm average diameter. In contrast, the existence of CB suspension produces rod-like PAni/CB core–shell nanocomposites, and decreases the average diameter to nearly 200
nm. XRD and Raman spectroscopy were employed to characterize the as-obtained CB powders, PAni and PAni/CB nanocomposites. Measurement of electric conductivity shows that incorporation on CB particles during electrochemical synthesis increased the obtained conductance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A unique novel self-assembled nanostructured alumina array with nanoscale grooves can be induced and controlled in nanometer dimension by a general electrochemical oxidation of aluminum in sulfuric ...acid. Almost inter-perpendicular self-assembled alumina nanostructure arrays separated by a few tens nanometer thick interface sheet were also observed in many domains. And the formation of this nanostructured array is considered as the result of the special competition balance between electrochemical oxidation and etching. Because of similarities of aluminum anodization with semiconductor anodization, our results may be proved useful for Si or GaAs nanostructure synthesis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The preparation of polyaniline nanofibers in aqueous solution was studied as functions of the concentrations and ratios of reactants. The morphology and microstructure of polyaniline nanofibers are ...affected by the concentrations and proportions of the reactants. A special kind of sea cucumber-like polyaniline nanofibers can be prepared under control of reaction conditions. Secondary growth is the formation mechanism. In addition, the bulk electrical conductivity of these sea cucumber-like polyaniline nanofibers was higher than that of other common polyaniline nanofibers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Raman spectroscopy was used to measure Raman spectra of the inner SiC fibers and surface C-rich layers of SiC fibers, composite precursors and SiCf/Ni-Cr-Al composites. The residual stresses of the ...inner SiC fibers and surface C-rich layers were calculated, and the effect of the (Al + Al2O3) diffusion barrier layer on the interfacial residual stress in the composites was analyzed in combination with the interface microstructure and energy disperse spectroscopy (EDS) elements lining maps. The results show that the existence of (Al + Al2O3) diffusion barrier improves the compatibility of the SiCf/Ni-Cr-Al interface, inhibits the adverse interfacial reaction, and relieves the residual stress inside SiC fibers and at the interface of composite material. Heat treatment can reduce the residual stress at the interface. As the heat treatment time increases, the residual stress at the interface decreases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this work, a modified approach for preparing CVD SiC fiber-reinforced superalloy matrix composites was rationally developed. The composites were fabricated by vacuum hot pressing (VHP) process ...using precursor wires coated with (Al + Al2O3) diffusion barrier layers and GH4169 superalloy coatings. BNi-7 brazing filler metals were introduced on the surface of precursor wires in order to decrease the temperature of the VHP process. It was found that the VHP temperature was reduced by about 100 °C, and the melting, diffusion, nucleation and growth processes of BNi-7 fillers at 900 °C motivated the recrystallization and plastic flow of the matrix under the increasing pressure, thereby a compact composite composed of intact SiC fibers and fine equiaxial grain structure superalloy matrix was achieved. Meanwhile, the elements were distributed homogeneously among the fibers in the composite and no interfacial reactions occurred. This method provides a new insight for designing and manufacturing high-quality composites in practical engineering.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this work, the effects of Cr and Al contents on the preparation of SiC fiber-reinforced NiCrAl alloy matrix composites (SiC
f
/Ni–20Cr–5Al, SiC
f
/Ni–15Cr–5Al, SiC
f
/Ni–10Cr–5Al and SiC
f
.../Ni–10Cr–3Al) were thoroughly discussed. The composites were prepared by vacuum hot pressing process using matrix-coated fibers. It was found that Cr solute atoms played a significant role in retarding the recrystallization of NiCrAl alloy matrix, and the Al elements in the form of γ′-Ni
3
Al phase had a suppression effect on the plastic flow of the matrix. Therefore, the reduction in Cr and Al contents was conductive to the recrystallization and plastic flow of NiCrAl alloy matrix, thereby reduced the size and number of micro-voids in the composite. In addition, this work provides some guidance for designing and manufacturing reasonable SiC fiber-reinforced Ni alloy matrix composites.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Electroencephalography (EEG) signals, known for convenient non-invasive acquisition but low signal-to-noise ratio, have recently gained substantial attention due to the potential to decode natural ...images. This paper presents a self-supervised framework to demonstrate the feasibility of learning image representations from EEG signals, particularly for object recognition. The framework utilizes image and EEG encoders to extract features from paired image stimuli and EEG responses. Contrastive learning aligns these two modalities by constraining their similarity. With the framework, we attain significantly above-chance results on a comprehensive EEG-image dataset, achieving a top-1 accuracy of 15.6% and a top-5 accuracy of 42.8% in challenging 200-way zero-shot tasks. Moreover, we perform extensive experiments to explore the biological plausibility by resolving the temporal, spatial, spectral, and semantic aspects of EEG signals. Besides, we introduce attention modules to capture spatial correlations, providing implicit evidence of the brain activity perceived from EEG data. These findings yield valuable insights for neural decoding and brain-computer interfaces in real-world scenarios. The code will be released on https://github.com/eeyhsong/NICE-EEG.
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