Oxygen-assisted preparation of mechanoluminescent ZnS：Mn for dynamic pressure mapping

Mechanoluminescent materials that convert mechanical stimuli to light emission have attracted extensive attention for potential applications in human-machine interactions. Here, we report a simple and available novel approach for the oxygen-assisted preparation of ZnS：Mn particles by solid-state reaction at atmospheric pressure without the formation of the corresponding oxides. The existence of O2 has a positive impact on the formation of S vacancies in wurtzite-phase ZnS, leading to the introduction of Mn2＋ ion luminescent centers and shallow donor levels, which can improve the electron-hole recombination rate. The O2 ratio and Mn2＋ ion doping concentration have significant effects on the luminous efficienc）5 which is optimal at 1%-20% and 1 at.%-2 at.% respectively. In addition, a device based on the piezo-photonic effect with excellent pressure sensitivity of 0.032 MPa-1 was fabricated, which can map the two-dimensional pressure distribution ranging from 2.2 to 40.6 MPa in situ. This device can be applied to real-time pressure mapping, smart sensor networks, high-level security systems, human-machine interfaces, and artificial skins.

Hierarchical Honeycomb-Structured Electret/Triboelectric Nanogenerator for Biomechanical and Morphing Wing Energy Harvesting

Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compact mesostructures,excellent energy absorption properties and considerable weight to strength ratios.Herein,a honeycomb-inspired triboelectric nanogenerator(h-TENG)is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure.The wavy surface comprises a multilayered thin film structure(combining polyethylene terephthalate,silver nanowires and fluorinated ethylene propylene)fabricated through high-temperature thermoplastic molding and wafer-level bonding process.With superior synchronization of large amounts of energy generation units with honeycomb cells,the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage,short-circuit current and output power of 1207 V,68.5μA and 12.4 mW,respectively,corresponding to a remarkable peak power density of 0.275 mW cm^(−3)(or 2.48 mW g^(−1))under hand pressing excitations.Attributed to the excellent elastic property of self-rebounding honeycomb structure,the flexible and transparent h-TENG can be easily pressed,bent and integrated into shoes for real-time insole plantar pressure mapping.The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time.This research demonstrates this new conceptualizing single h-TENG device’s versatility and viability for broad-range real-world application scenarios.

PLASMA SODIUM AND NaCl-SENSITIVE HYPERTENSION

Objective To test the following three hypotheses: ①plasma sodium concentration displays a 24-hour rhythm; ②the circadian rhythm of plasma sodium is disrupted in SHR fed a basal NaCl diet; ③high NaCl diet elevates plasma sodium concentration and may lead to an increase in mean arterial pressure (MAP) of SHR. Methods After having been instrumented with arterial catheter at 9 weeks of age, all rats (Spontaneously Hypertensive Rat, SHR; Wistar-Kyoto Rat, WKY) experienced two experimental protocols, the mean arterial pressure and heart rate were monitored and the blood samples also been analysed for sodium contents. Results On basal NaCl diet, plasma sodium concentrations in SHR were significantly higher than those of WKY at almost every time point measured and the plasma sodium concentration and MAP rhythms were in nearly opposite phases; on high NaCl diet, the MAP and plasma sodium rhythms were essentially opposite in WKY. In SHR, the plasma sodium rhythm was inversely related to the MAP rhythm. Conclusion Plasma sodium displays a significant circadian rhythm in rats. The high NaCl diet disrupts the normal plasma sodium circadian rhythm only in SHR.

Muscle recruitment patterns and saddle pressure indexes with alterations in effective seat tube angle

Alteration of the effective seat tube angle(ESTA)may affect muscle activation patterns of the lower limbs in cycling.There is conflicting evidence due to inadequate kinematic controls in previous studies.The primary aim of this study was to determine the muscle activity of seven lower limb muscles during alterations of the ESTA by altering the position of both the handlebars and saddle forwards or backwards by 3 cm while ensuring controlled kinematics.Secondly,to determine the effect on the saddle pressure indexes.Ten participants performed two 5 min electromyography(EMG)trials at 70%of peak power output(PPO)for three consecutive visits.There was a significant increase in muscle activity in the biceps femoris,gluteus maximus,and medial gastrocnemius with reductions in ESTA while a significant increase in tibialis anterior with increases in ESTA was observed.Saddle pressure indices demonstrated a significant change in frontal versus back pressure as well as mean pubic pressure with changes in ESTA.Alteration in the ESTA affects muscle activity in some,but not all of the lower limb muscles.Further research needs to be conducted to adequately understand the mechanism behind the differences in muscle activation.

Combined Use of FSR Sensor Array and SVM Classifier for Finger Motion Recognition Based on Pressure Distribution Map

For controlling dexterous prosthetic hand with a high number of active Degrees of Freedom （DOF）, it is necessary to reliably extract control volitions of finger motions from the human body. In this study, a large variety of finger motions are discriminated based on the diversities of the pressure distribution produced by the mechanical actions of muscles on the forearm. The pressure distribution patterns corresponding to the motions were measured by sensor array which is composed of 32 Force Sensitive Resistor （FSR） sensors. In order to map the pressure patterns with different finger motions, a multiclass classifier was designed based on the Support Vector Machine （SVM） algorithm. The multi-subject experiments show that it is possible to identify as many as seventeen different finger motions, including individual finger motions and multi-finger grasping motions, with the accuracy above 99% in the in-session validation. Further, the cross-session validation demonstrates that the performance of the proposed method is robust for use if the FSR array is not reset. The results suggest that the proposed method has great application prospects for the control of multi-DOF dexterous hand prosthesis.