RESUMEN
Flexible electronics have gained great attention in recent years owing to their promising applications in biomedicine, sustainable energy, human-machine interaction, and toys for children. Paper mainly produced from cellulose fibers is attractive substrate for flexible electronics because it is biodegradable, foldable, tailorable, and light-weight. Inspired by daily handwriting, the rapid prototyping of sensing devices with arbitrary patterns can be achieved by directly drawing conductive inks on flat or curved paper surfaces; this provides huge freedom for children to design and integrate "do-it-yourself (DIY)" electronic toys. Herein, viscous and additive-free ink made from Ti3 C2 TX MXene sediment is employed to prepare disposable paper electronics through a simple ball pen drawing. The as-drawn paper sensors possess hierarchical microstructures with interweaving nanosheets, nanoflakes, and nanoparticles, therefore exhibiting superior mechanosensing performances to those based on single/fewer-layer MXene nanosheets. As proof-of-concept applications, several popular children's games are implemented by the MXene-based paper sensors, including "You say, I guess," "Emotional expression," "Rock-Paper-Scissors," "Arm wrestling," "Throwing game," "Carrot squat," and "Grab the cup," as well as a DIY smart whisker for a cartoon mouse. Moreover, MXene-based paper sensors are safe and disposable, free from producing any e-waste and hazard to the environment.
RESUMEN
An improved hybrid homotopy method is proposed to decouple the multi-input model of tactile sensors. The time-embedded homotopy algorithm is proved to be very suitable for solving the problem. Three tracking factors that control the efficiency of the algorithm are studied: tracking operator, stepsize, and accuracy. Trust region methods are applied to track the zero paths instead of the traditional differential algorithm, and a periodic sampling method is proposed to improve the efficiency of the algorithm. Numerical experiments show that both the robustness and accuracy have received a huge boost after the hybrid algorithm is applied.
RESUMEN
An electrochemical microcantilever (EMC) was used to study the intermolecular interaction of self-assembly monolayers (SAMs) with different n-alkanethiols chain lengths (n = 0, 4, 6, 8, 12, 16) on a Au-coated microcantilever surface. Comparing potential cycling and steps in NaClO(4) solution within the same potential range, the deflection rate of bare microcantilevers is much smaller for the former which revealed that potential excitation, i.e. the surface charge, played the dominant role in driving the instant and large deflection of the bare microcantilever, while the smaller deflection amplitude of the former implied that adsorption of ClO(4)( - ) had an adverse effect on the potential-induced stress. Upon adsorption of SAMs, the deflection amplitude of the microcantilever under the potential step was much smaller than that of a bare microcantilever, and linearly decreased with the chain length increasing for n ≤ 8 (the linear correlation coefficient and the slope are 0.98 and about - 10.4 nm per CH(2) unit, respectively), following a transition (8 ≤ n ≤ 12) to a stable state (n ≥ 12). The decrease of deflection amplitude and faster decay of deflection rate of the SAMs modified microcantilever under the potential step implyed increasing compactness of the SAMs with longer chains.
RESUMEN
Background: Accurate and reliable self-report measurement tools examining depressive symptoms are scant in child psychiatry. This study assessed the psychometric properties of the Chinese Version of the Quick Inventory of Depressive Symptomatology-Self-Report (C-QIDS-SR) in depressed adolescents in China. Methods: Adolescents with major depressive episodes or bipolar depressive episodes were assessed using the C-QIDS-SR. The structure validity of the C-QIDS-SR was estimated using principal component analysis with varimax rotation. Results: A total of 246 depressed adolescents were included in the study. Cronbach's alpha was 0.77. The correlation coefficient between the baseline and endpoint assessments was 0.49 (p < 0.001), whereas, the correlation coefficient between the C-QIDS-SR and the Hamilton Rating Scale for Depression-17 items (HAMD-17) was 0.63 (p < 0.001). Principal component analysis with varimax rotation demonstrated the unidimensional structure of the C-QIDS-SR. Conclusion: The C-QIDS-SR is a reliable and valid instrument with acceptable psychometric properties to measure depressive symptoms in adolescents.
RESUMEN
Nano-sized TiO2 photocatalysts were prepared by drying the ethanol gel of titanium tetrabutoxide through natural state, supercritical ethanol, supercritical carbon dioxide drying methods and characterized by XRD, FTIR spectroscopy, FT-Raman spectroscopy and fluorescent spectroscopy, respectively. We regard degradation of rhodamine B by photocatalyst as a model reaction, and compare photocatalytic activities of samples obtained. The experimental results show that different drying methods have strong effect on crystal structure, energy band structure, optical adsorption property, surface quality and photocatalytic activity, TiO2 photocatalyst prepared by supercritical carbon dioxide drying method has superior photocatalytic activity.