Junction Piezotronic Transistor Arrays Based on Patterned ZnO Nanowires for High-Resolution Tactile and Photo Mapping.

Recently, a great deal of interest has been focused on developing sensors that can measure both pressure and light. However, traditional sensors are difficult to integrate into silicon (Si)-based integrated circuits. Therefore, it is particularly important to design a sensor that operates on a new principle. In this paper, junction piezotronic transistor (JPT) arrays based on zinc oxide (ZnO) nanowire are demonstrated. And the JPT arrays show high spatial resolution pressure and light mapping with 195 dpi. Because ZnO nanowires are arranged vertically above the p-type Si channel's center of the transistor, the width of the heterojunction depletion region is constricted by the positive piezoelectric potential generated by strained ZnO. In addition, photogenerated charge carriers can be created in the Si channel when JPT is stimulated by light, which increases its electrical conductivity. Consequently, the external pressure and light distribution information can be obtained from the variation in the output current of the device. The prepared JPT arrays can be compatible with Si transistors, which make them highly competitive and make it possible to incorporate both pressure and light sensors into large integrated circuits. This work will contribute to many applications, such as intelligent clothing, human-computer interaction, and electronic skin.

Effects of different remediation methods on phosphorus transformation and availability.

The effects of different heavy metal pollution remediation methods on soil nutrient transformation and soil health remain unclear. In this study, the effects of phytoextraction (PE) and passivation remediation (PR) on Cd-polluted soil phosphorus transformation and availability were compared by pot experiment. The results showed that PE significantly reduced the concentrations of total and available Cd (both H2O-Cd and DTPA-Cd) in soil, PR also decreased available Cd content but had no significant effect on total Cd content. PE slightly increased soil pH and NH4+-N content, while PR significantly increased soil pH, NO3--N and AK content. PE promoted the conversion of stable P (including HCl-Pi and residual-Pt), and increased the content of labile P (including H2O-Pi, NaHCO3-Pi and NaHCO3-Po) and the proportion of moderately labile P (including NaOH-Pi and NaOH-Po), while PR showed the opposite trend. PE showed a higher soil phoC gene abundance and acid phosphatase (ACP) activity, while PR showed a higher phoD gene copies and alkaline phosphatase (ALP) activity. Soil bacteria and phoD-harboring bacteria community was significantly affected by remediation methods and soil types. Compared with PR, PE reduced phoD-harboring bacterial diversity but significantly increased the abundance of genera associated with P dissolution (Streptomyces) and P conversion (Bradyrhizobium and Frankia), both of which were significantly positively correlated with labile P or moderately labile P. In general, compared with PR, PE can effectively remove soil Cd pollution, while maintaining a higher content of labile P and a higher proportion of moderately labile P, which can be considered as a green and sustainable remediation strategy conducive to soil quality.

Hierarchical Synergistic Structure for High Resolution Strain Sensor with Wide Working Range.

Strain sensors have been attracting tremendous attention for the promising application of wearable devices in recent years. However, the trade-off between high resolution, high sensitivity, and broad detection range is a great challenge for the application of strain sensors. Herein, a novel design of hierarchical synergistic structure (HSS) of Au micro cracks and carbon black (CB) nanoparticles is reported to overcome this challenge. The strain sensor based on the designed HSS exhibit high sensitivity (GF > 2400), high strain resolution (0.2%) even under large loading strain, broad detection range (>40%), outstanding stability (>12000 cycles), and fast response speed simultaneously. Further, the experiments and simulation results demonstrate that the carbon black layer greatly changed the morphology of Au micro-cracks, forming a hierarchical structure of micro-scale Au cracks and nano-scale carbon black particles, thus enabling synergistic effect and the double conductive network of Au micro-cracks and CB nanoparticles. Based on the excellent performance, the sensor is successfully applied to monitoring tiny signals of the carotid pulse during body movement, which illustrates the great potential in the application of health monitoring, human-machine interface, human motion detection, and electronic skin.

Localizing strain via micro-cage structure for stretchable pressure sensor arrays with ultralow spatial crosstalk.

Tactile sensors with high spatial resolution are crucial to manufacture large scale flexible electronics, and low crosstalk sensor array combined with advanced data analysis is beneficial to improve detection accuracy. Here, we demonstrated the photo-reticulated strain localization films (prslPDMS) to prepare the ultralow crosstalk sensor array, which form a micro-cage structure to reduce the pixel deformation overflow by 90.3% compared to that of conventional flexible electronics. It is worth noting that prslPDMS acts as an adhesion layer and provide spacer for pressure sensing. Hence, the sensor achieves the sufficient pressure resolution to detect 1 g weight even in bending condition, and it could monitor human pulse under different states or analyze the grasping postures. Experiments show that the sensor array acquires clear pressure imaging and ultralow crosstalk (33.41 dB) without complicated data processing, indicating that it has a broad application prospect in precise tactile detection.

[Effects of slope position and aspect on structure and species diversity of shrub community in the Jiajin Mountains, Sichuan Province, China]. / å¡å‘å’Œå¡ä½å¯¹å››å·å¤¹é‡‘å±±çŒä¸›ç¾¤è½ç»“æž„ä¸Žç‰©ç§å¤šæ ·æ€§ç‰¹å¾çš„å½±å“.

We examined the impacts of slope direction and position on the community structure and species diversity of shrub community in Jiajin Mountains. The results showed that a total of 186 vascular plant species belonging to 50 families and 127 genera were recorded in the 24 sample plots. 32 species belonging to 14 families, 22 genera were recorded in the shrubs layer, with most species distributed at lower position of the shady slope. 154 species belonging to 43 families and 109 genera were recorded in the herbaceous layer, with the species number being the lowest on the shady slope. The average height of the shrub layer showed a decreasing order of sunny slope, semi-sunny slope, and shady slope, while an opposite order was observed for the average density. The average height of the herb layer was in the decreasing order of the shady slope, semi-sunny slope, sunny slope, whereas no significant changes were observed for the average density. The slope position had significant effect only on the average height of the herbaceous layer on the sunny slope. The overall level of species diversity in the shrub layer on the shady slope was relatively high, while that in the herbaceous layer was relatively high at the lower position of the sunny slope and at the middle position of the shady slope. Slope aspect had significant effect on species richness index, Shannon diversity index, Simpson dominance index, Pielou evenness index of shrub and herb layers except for Simpson index of herb layer. Slope position did not affect these indices. The interaction effect of slope aspect and position on the diversity index for herb layer was greater than that for the shrub layer. Results from redundancy analysis showed that species diversity was related to sin(aspect), cos(aspect), and community structure.