Accompanying the boom in multifunctional wearable electronics, flexible, sustainable, and wearable power sources are facing great challenges. Here, a stretchable, washable, and ultrathin skin‐inspired triboelectric nanogenerator (SI‐TENG) to harvest human motion energy and act as a highly sensitive self‐powered haptic sensor is reported. With the optimized material selections and structure design, the SI‐TENG is bestowed with some merits, such as stretchability (≈800%), ultrathin (≈89 µm), and light‐weight (≈0.23 g), which conformally attach on human skin without disturbing its contact. A stretchable composite electrode, which is formed by homogenously intertwining silver nanowires (AgNWs) with thermoplastic polyurethane (TPU) nanofiber networks, is fabricated through synchronous electrospinning of TPU and electrospraying of AgNWs. Based on the triboelectrification effect, the open‐circuit voltage, short‐circuit current, and power density of the SI‐TENG with a contact area of 2 × 2 cm2 and an applied force of 8 N can reach 95 V, 0.3 µA, and 6 mW m−2, respectively. By integrating the signal‐processing circuits, the SI‐TENG with excellent energy harvesting and self‐powered sensing capability is demonstrated as a haptic sensor array to detect human actions. The SI‐TENG exhibits extensive applications in the fields of human–machine interface and security systems.
Flexible pressure sensors have emerged
as an indispensable part
of wearable devices due to their application in physiological activity
monitoring. To realize long-term on-body service, they are increasingly
required for properties of conformability, air permeability, and durability.
However, the enhancement of sensitivity remains a challenge for ultrathin
capacitive sensors, particularly in the low-pressure region. Here,
we introduced a highly sensitive and ultrathin capacitive pressure
sensor based on a breathable all-fabric network with a micropatterned
nanofiber dielectric layer, an all-fabric capacitive sensor (AFCS).
This all-fabric network endows a series of exceptional performances,
such as high sensitivity (8.31 kPa–1 under 1 kPa),
ultralow detection limit (0.5 Pa), wide detection range (0.5 Pa to
80 kPa), and excellent robustness (10 000 dynamic cycles).
Besides, the all-fabric structure provides other properties for the
AFCS, e.g., high skin conformability, super thinness (dozens of micrometers),
and exceptional air permeability. Our AFCS shows promising potential
in breathing track, muscle activity detection, fingertip pressure
monitoring, and spatial pressure distribution, paving way for comfortable
skinlike epidermal electronics.
The invasive species Spartina alterniora Loisel was introduced to the eastern coast of China in the 1970s and 1980s for the purposes of land reclamation and the prevention of soil erosion. The resulting interspecific competition had an important influence on the distribution of native vegetation, which makes studying the patterns and mechanisms of the interactions between Spartina alterniora Loisel and the native species Phragmites australis (Cav.) Trin ex Steud in this region very important. There have been some researches on the interspecific interactions between P. australis and S. alterniora in the Dongtan wetland of Chongming, east China, most of which has focused on the comparison of their physiological characteristics. In this paper, we conducted a neighbor removal experiment along a tidal gradient to evaluate the relative competitive abilities of the two species by calculating their relative neighbor effect (RNE) index. We also looked at the influence of environmental stress and disturbance on the competitive abilities of the two species by comparing interaction strength (I) among different tidal zones both for P. australis and S. alterniora. Finally, we measured physiological characteristics of the two species to assess the physiological mechanisms behind their different competitive abilities. Both negative and positive interactions were found between P. australis and S. alterniora along the environmental gradient. When the direction of the competitive intensity index for P. australis and S. alterniora was consistent, the competitive or facilitative effect of S. alterniora on P. australis was stronger than that of P. australis on S. alterniora. The interspecific interactions of P. australis and S. alterniora varied with environmental conditions, as well as with the method used, to measure interspecific interactions.
A lithium-ion battery separator is one of the essential components of a lithium-ion battery structure. It has attracted wide attention as a result of providing efficient transmission channels of lithium ions, isolating pro and con electrodes to prevent short circuits. However, traditional petroleum-based separators encounter great challenges in battery recycling, charge transfer, sustainable use, etc. Cellulose provides an environmentally friendly, green alternative. In this mini review, we summarize the working principle of lithium-ion batteries and the main technical requirements for the use of separators as well as the latest research direction of cellulose-based lithium-ion battery separators. It brings breakthroughs in the fields of electrochemistry and energy chemistry, polymer chemistry, and energy materials and also provides a new inspiration for the commercialization of lithium-ion-battery-coating separators.
We describe three new Achnanthidium species, A. lacustre sp. nov., A. sublanceolatum sp. nov., and A. taipingensis sp. nov., from Taiping Lake, Anhui Province (China) based on light and scanning electron microscopy. A. lacustre sp. nov. belongs to the "A. minutissimum complex" of the genus, based on it having straight external distal raphe fissures and round to elliptical areolae. Both A. sublanceolatum sp. nov., and A. taipingensis sp. nov. belong to the "A. pyrenaicum complex" of the genus, based on them having transpically-elongated areolae and deflected external distal raphe fissures. All three species are sufficiently different from other similar species based on valve outline, shape of the axial and center areas, and striae density. These three new species are all observed in benthic collections from Taiping Lake.
Abstract:Benthic diatoms are an indispensable link of the water ecological system in terms of energy flow and material cycling, and they directly or indirectly reflect the status of the water environment. We sampled benthic diatoms and environmental factors from April to May of 2013 from 53 sites along the Ying River to study their application in local water trophic status assessment, with a focus on the dominant benthic diatom species, their composition and distribution pattern, and the relationship between benthic diatoms and environmental factors. A total of 370 species and varieties were identified, belonging to 56 genera and six orders. The dominant species were as follows: Nitzschia inconspicua Grunow, Achnanthidium minutissimum (Kützing) Czarnecki, Navicula aitchelbee L. L. Bahls, Nitzschia palea (Kützing) Smith, Cyclotella meneghiniana Kützing, Navicula submuralis Hustedt and Mayamaea atomus (Kützing) Lange-Bertalot. The Ying River was divided into five orders using the Strahler method and three regions according to total nitrogen, total phosphorus and ammonia nitrogen. In region Y-1, which had the lowest nutrient level, the dominant species was Achnanthidium minutissimum. In region Y-2, which had the highest nutrient level, Navicula aitchelbee, Nitzschia palea, and Cyclotella meneghiniana were dominant, while in region Y-3, which had moderate nutrient levels, Nitzschia inconspicua was dominant. Pearson's correlation analysis and canonical correspondence analysis (CCA) revealed a significant correlation between the environmental factors with dominant species and diatom indices (especially the SPI). Our study indicates that dominant species and diatom indices can, to some extent, indicate the environment, especially nutrient distribution.
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