The assessment of fabric quality is highly dependent on the human tactile sense, which is affected by many factors. There is currently no approach to measure fabric quality directly. To build the relationship between tactile perception and fabric texture, vibration data obtained from a biomimetic sensor while scanning fabric surfaces were recorded and compared with the human judgments. Human subjective sensing experiments were performed with 20 volunteers by classifying texture into 10 grades according to three dimensions: Rough–Smooth, Coarse–Fine and Complex–Uniform. The vibrations and the coefficient of friction (COF) between the skin and fabric were measured using an artificial finger and a tribometer as the artificial finger scanned across various fabrics. Five characteristic values were extracted based on features of the fabric texture from the vibration data: peak average (PA), peak ratio (PR), spectral centroid (SC), power (P) and Shannon entropy (SE).These feature values were evaluated by comparison with those from human sensing experiments. It was found that P, SC, SE and COF could characterize the perceived Rough–Smooth, Coarse–Fine, Complex–Uniform and surface comfort, respectively.

In this study, the tribological behavior of lamellar MoO₃ as a lubricant additive was investigated under different concentrations, particle sizes, normal loads, velocity, and temperature. The friction and wear tests were performed using a tribometer and with a reciprocating motion. The results indicate that the friction-reducing ability and antiwear property of the base oil can be improved effectively with the addition of lamellar MoO₃. The 0.5 wt % and 0.1 wt % concentrations of MoO₃ yield the best antifriction and antiwear effects, respectively. The maximum friction and wear reduction is 19.8% and 55.9%, compared with that of the base oil. It is also found the MoO₃ additive can decrease the friction considerably under a high velocity and normal load, and increase the working temperature. The smaller the size of MoO₃, the better the friction-reducing effect the lamellar MoO₃ shows. The friction-reducing and antiwear mechanisms of lamellar MoO₃ were discussed.

This study investigates whether the combined effect of kinesthetic motor imagery-based brain computer interface (KI-BCI) and transcranial direct current stimulation (tDCS) on upper limb function in subacute stroke patients is more effective than using KI-BCI or tDCS alone. Forty-eight subacute stroke survivors were randomized to the KI-BCI, tDCS, or BCI-tDCS group. The KI-BCI group performed 30 min of KI-BCI training. Patients in tDCS group received 30 min of tDCS. Patients in BCI-tDCS group received 15 min of tDCS and 15 min of KI-BCI. The treatment cycle was five times a week, for four weeks. After all intervention, the Fugl-Meyer Assessment-Upper Extremity, Motor Status Scale, and the Modified Barthel Index scores of the KI-BCI group were superior to those of the tDCS group. The BCI-tDCS group was superior to the tDCS group in terms of the Motor Status Scale. Although quantitative EEG showed no significant group differences, the quantitative EEG indices in the tDCS group were significantly lower than before treatment. In conclusion, after treatment, although all intervention strategies improved upper limb motor function and daily living abilities in subacute stroke patients, KI-BCI demonstrated significantly better efficacy than tDCS. Under the same total treatment duration, the combined use of tDCS and KI-BCI did not achieve the hypothesized optimal outcome. Notably, tDCS reduced QEEG indices, possibly indicating favorable future outcomes in future. Trial registry number: ChiCTR2000034730.

Tactile perception plays a critical role in the interaction of humans and environment. It begins with the mechanical stimulation induced by friction and is processed in the somatosensory cortex. To quantify the tactile perceptions of textile fabrics, the mechanical properties of fabrics and the features extracted from the friction and vibration signals were correlated with the subjective sensation rated by questionnaires. Meanwhile, the technique of functional magnetic resonance imaging (fMRI) was used to identify the brain areas responsible for the tactile perception of textile fabrics. The results showed that during the tactile perception of textile fabrics, the coefficient of friction increased with the increasing normal load, indicating that the deformation mechanism of skin was relevant to the friction of skin against fabrics. The features of spectral centroid (SC), coefficient of friction, and diameter and critical buckling force of fiber had a strong correlation with the perceived fineness, slipperiness, and prickliness of fabrics, respectively. The postcentral gyrus, supramarginal gyrus, and precentral gyrus, with the corresponding functional regions of the primary somatosensory cortex (SI), secondary somatosensory cortex (SII), primary motor cortex (MI), and secondary motor cortex (MII), were involved with the perceptions of fabric textures. The fiber properties and fabric surface structures that caused the multidimensional feelings tended to induce the large area, intensity, and percent signal change (PSC) of brain activity. This study is meaning for evaluating the tactile stimulation of textile fabrics and understanding the cognitive mechanism in the tactile perception of textile fabrics.

Silicon undergoes a brittle-to-ductile transition as its characteristic dimension reduces from macroscale to nanoscale. The thorough understanding of the plastic deformation mechanism of silicon at the nanoscale is still challenging, although it is essential for developing Si-based micro/nanoelectromechanical systems (MEMS/NEMS). Given the wide application of silicon in extreme conditions, it is, therefore, highly desirable to reveal the nanomechanical behavior of silicon from cryogenic temperature to elevated temperature. In this paper, large-scale molecular dynamics (MD) simulations were performed to reveal the spherical nanoindentation response and plastic deformation mechanism of (110)Si at the temperature range of 0.5 K to 573 K. Special attention was paid to the effect of temperature. Multiple pop-ins detected in load/pressure-indentation strain curves are impacted by temperature. Four featured structures induced by nanoindentation, including high-pressure phases, extrusion of α-Si, dislocations, and crack, are observed at all temperatures, consistent with experiment results. The detailed structure evolution of silicon was revealed at the atomic scale and its dependence on temperature was analyzed. Furthermore, structure changes were correlated with pop-ins in load/pressure-indentation strain curves. These results may advance our understanding of the mechanical properties of silicon.