Efficient removal of particulate matter (PM) is the major goal for various air cleaning technologies due to its huge impact on human health. Here, a washable high‐efficiency triboelectric air filter ...(TAF) that can be used multiple times is presented. The TAF consists of five layers of the polytetrafluoroethylene (PTFE) and nylon fabrics. Compared with traditional electrostatic precipitator, which requires a high‐voltage power supply, the TAF can be charged by simply rubbing the PTFE and nylon fabrics against each other. The electrical properties of the TAF are evaluated through the periodic contacting–separating of the PTFE and nylon fabrics using a linear motor, and an open‐circuit voltage of 190 V is achieved. After charging, the TAF has a removal efficiency of 84.7% for PM0.5, 96.0% for PM2.5, which are 3.22 and 1.39 times as large as the uncharged one. Most importantly, after washing several times, the removal efficiency of the TAF maintains almost the same, while the commercial face mask drops to 70% of its original efficiency. Furthermore, the removal efficiency of the PM2.5 is very stable under high relative humidity. Therefore, the TAF is promising for fabricating a reusable and high‐efficiency face mask.
A multilayer triboelectric air filter consists of five layers of polytetrafluoroethylene (PTFE) and nylon fabrics. A high removal efficiency is achieved by rubbing the fabrics against each other, and the removal efficiency maintains high under high humidity, in a durability test or after several washing cycles. Moreover, a face mask made of this air filter can be used in daily life.
We study a double-cavity optomechanical system in which a movable mirror with perfect reflection is inserted between two fixed mirrors with partial transmission. This optomechanical system is driven ...from both fixed end mirrors in a symmetric scheme by two strong coupling fields and two weak probe fields. We find that three interesting phenomena: coherent perfect absorption (CPA), coherent perfect transmission (CPT), and coherent perfect synthesis (CPS) can be attained within different parameter regimes. That is, we can make two input probe fields totally absorbed by the movable mirror without yielding any energy output from either end mirror (CPA); make an input probe field transmitted from one end mirror to the other end mirror without suffering any energy loss in the two cavities (CPT); make two input probe fields synthesized into one output probe field after undergoing either a perfect transmission or a perfect reflection (CPS). These interesting phenomena originate from the efficient hybrid coupling of optical and mechanical modes and may be all-optically controlled to realize novel photonic devices in quantum information networks.
•A plasma-assisted rotating disk reactor has been innovatively developed.•The rotating disk was used as ground electrode to improve the discharge uniformity.•The mass transfer efficiency was enhanced ...in the plasma-RDR.•A discussion for the enhancement of degradation efficiency was presented.
Plasma-based process intensification is considered as a promising technology in advanced oxidation processes (AOPs) for the wastewater treatment. In this work, we have developed a novel plasma-assisted rotating disk reactor (plasma-RDR). The rotating disk was used as ground electrode to improve the discharge uniformity, and also as an internal to enhance the mass transfer efficiency. Experimental results show that the degradation efficiency of Rhodamine B (RhB) in the plasma-RDR increased by 60% within 30 min when the rotational speed varied from 0 to 500 rpm. A discussion for the enhancement of degradation efficiency in the plasma-RDR was presented. Effects of peak voltage, electrode gap, and other operating conditions on the degradation efficiency of RhB in the plasma-RDR were investigated. Major intermediates of RhB degradation after the plasma treatment were also analyzed.
1. Flowering plants exhibit striking interspecific and intraspecific variation in flower number, which strongly influences the reproductive success of animal-pollinated plants. However, the ...reproductive consequences of producing a single flower are poorly understood. 2. Here, we test if plants producing a single flower have a reproductive disadvantage compared with plants producing multiple flowers by combining field investigation of five deceptive orchids and a survey of published literature. Pollen limitation was estimated by comparing fruit production between hand pollination and open pollination. Flowering frequency was monitored over years to assess the potential advantage of producing a single flower. 3. Both single- and multiple-flowered species suffered strong pollen limitation. However, single-flowered species had significantly lower fruit set and produced fewer seeds per individual, although they had a significantly higher pollen removal than species with multiple flowers. A phylogenetically independent contrast of 28 species representing four of the five subfamilies of Orchidaceae revealed that fruit set was significantly positively associated with flower number. Both pollen removal and fruit set had a positive relationship with flower number within the multipleflowered species. 4. Synthesis. Current data and phylogenetically independent contrast support the hypothesis that producing a single flower has reproductive disadvantages. Single-flowered species may compensate for low female success through high flowering frequency over years. This study provides insight into costs and benefits of producing a single flower in deceptive orchids.
We developed a high-efficiency rotating triboelectric nanogenerator (R-TENG)-enhanced multilayered antibacterial polyimide (PI) nanofiber air filters for removing ultrafine particulate matter (PM) ...from ambient atmosphere. Compared to single-layered PI nanofiber filters, the multilayered nanofiber filter can completely remove all of the particles with diameters larger than 0.54 μm and shows enhanced removal efficiency for smaller PM particles. After connecting with aR-TENG, the removal efficiency of the filer for ultrafine particles is further enhanced. The highest removal efficiency for ultrafine particulate matter is 94.1% at the diameter of 53.3 nm and the average removal efficiency reached 89.9%. Despite an increase in the layer number, the thickness of each individual layer of the film decreased, and hence, the total pressure drop of the filter decreased instead of increasing. Moreover, the nanofiber film exhibited high antibacterial activity because of the addition of a small amount of silver nanoparticles. This technology with zero ozone release and low pressure drop is appropriate for cleaning air, haze treatment, and bacterial control.
Many organic reactions rely on CO
2
sources to generate important structural units and valuable chemicals. In this study, we compared the effects of cannabidiol (CBD) and cannabidiolic acid (CBDA) on ...the supercritical CO
2
(scCO
2
)-induced de/carboxylation reaction. The results showed that CBD was directly carboxylated in the ortho-position to form CBDA with up to 62% conversion. Meanwhile, CBDA decarboxylation occurred on hemp plant material via varying composition. Mechanistic studies revealed that CBD carboxylation was influenced not only by the physical properties of scCO
2
, but also by the vegetable matrix.
•HFMD cases with more severe CNS complications are linked to neurological sequelae.•Cognitive dysfunction is aggravated in HFMD cases with more severe CNS complications.•The risks of sequelae and ...cognitive deficits are similar among different pathogens.•HFMD cases without/with mild CNS involvement did not present with any sequelae.•Cognitive function was also associated with socioeconomic factors.
The aim of this study was to evaluate the long-term sequelae and cognitive profiles resulting from severe hand, foot, and mouth disease (HFMD) with central nervous system (CNS) involvement.
294 HFMD cases were included in a retrospective follow-up study. Physical examinations were conducted. The Chinese Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) was used to assess intelligence.
58 mild HFMD cases and 99 severe HFMD cases with mild CNS involvement did not present any neurological sequelae. In comparison, the sequelae incidence for severe HFMD with more severe CNS complications was 50.0%. The proportion of full-scale intelligence quotient (FSIQ) impairment was 45.0%. In the 2:6–3:11 age group, severe HFMD with more severe CNS complications and lower maternal education level were risk factors for verbal comprehension disorder. Urban–rural residence and lower paternal education level were risk factors for FSIQ disorder. Furthermore, in the 4:0–6:11 age group, severe HFMD with more severe CNS complication was a risk factor for visual spatial disorder and fluid reasoning disorder. Lower paternal education level was a risk factor for FSIQ disorder.
Early assessment and intervention among severe HFMD patients with more severe CNS involvement at a very young age will prove beneficial for their future performance.
Soil productivity (SP) without external fertilization influence is an important indicator for the capacity of a soil to support crop yield. However, there have been difficulties in estimating values ...of SPs for soils after various long-term field treatments because the treatment without external fertilization is used but is depleted in soil nutrients, leading to erroneous estimation. The objectives of this study were to estimate the change of SP across different cropping seasons using pot experiments, and to evaluate the steady SP value (which is defined by the basal contribution of soil itself to crop yield) after various long-term fertilization treatments in soils at different geographical locations. The pot experiments were conducted in Jinxian of Jiangxi Province with paddy soil, Zhengzhou of Henan Province with fluvo-aquic soil, and Gongzhuling of Jilin Province with black soils, China. Soils were collected after long-term field fertilization treatments of no fertilizer (control; CK-F), chemical fertilizer (NPK-F), and combined chemical fertilizer with manure (NPKM-F). The soils received either no fertilizer (F0) or chemical fertilizer (F1) for 3–6 cropping seasons in pots, which include CK-P (control; no fertilizer from long-term field experiments for pot experiments), NPK-P (chemical fertilizer from long-term field experiments for pot experiments), and NPKM-P (combined chemical and organic fertilizers from long-term field experiments for pot experiments). The yield data were used to calculate SP values. The initial SP values were high, but decreased rapidly until a relatively steady SP was achieved at or after about three cropping seasons for paddy and fluvo-aquic soils. The steady SP values in the third cropping season from CK-P, NPK-P, and NPKM-P treatments were 37.7, 44.1, and 50.0% in the paddy soil, 34.2, 38.1, and 50.0% in the fluvo-aquic soil, with the highest value observed in the NPKM-P treatment for all soils. However, further research is required in the black soils to incorporate more than three cropping seasons. The partial least squares path mode (PLS-PM) showed that total N (nitrogen) and C/N ratio (the ratio of soil organic carbon and total N) had positive effects on the steady SP for all three soils. These findings confirm the significance of the incorporation of manure for attaining high soil productivity. Regulation of the soil C/N ratio was the other main factor for steady SP through fertilization management.
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•A self-powered triboelectric catalyst is prepared by electrostatic spinning.•The triboelectric catalysts promote the generation of reactive oxygen species.•Triboelectric charges ...promote the continuous decomposition of intermediate products.•The CO2 production efficiency can be improved to78.93%.
The accumulation of intermediates is an important reason for the inactivation of many catalysts including formaldehyde (HCHO) degradation materials. Herein, self-powered triboelectric catalysts (MnOx-PMMA-SSM) with a three-dimensional nanocomposite structure self-assembled by nanoflowered MnOx inlaid porous polymethyl methacrylate (PMMA) nanofibers based on stainless steel mesh (SSM) substrate, is fabricated by electrostatic spinning and hydrolysis methods. The self-powered triboelectric catalysts can promote the generation of reactive oxygen species (O*) under the action of triboelectric charges from the friction between PMMA fibers and SSM driven by the wind, thus promoting the catalytic oxidation of HCHO and intermediates. In the 15 ppm HCHO atmosphere, the CO2 production efficiency for the self-powered triboelectric catalysts can improve 36.25% up to78.93% compared with traditional MnOx catalysts, and the catalyst life is as high as 72 h without evident decay. This research provides a new strategy for high-efficiency, long-term and zero-energy degradation HCHO at room temperature.
This paper proposes a novel energy-efficient oil shale pyrolysis process triggered by a topochemical reaction that can be applied in horizontal oil shale formations. The process starts by feeding ...preheated air to oil shale to initiate a topochemical reaction and the onset of self-pyrolysis. As the temperature in the virgin oil shale increases (to 250-300°C), the hot air can be replaced by ambient-temperature air, allowing heat to be released by internal topochemical reactions to complete the pyrolysis. The propagation of fronts formed in this process, the temperature evolution, and the reaction mechanism of oil shale pyrolysis in porous media are discussed and compared with those in a traditional oxygen-free process. The results show that the self-pyrolysis of oil shale can be achieved with the proposed method without any need for external heat. The results also verify that fractured oil shale may be more suitable for underground retorting. Moreover, the gas and liquid products from this method were characterised, and a highly instrumented experimental device designed specifically for this process is described. This study can serve as a reference for new ideas on oil shale in situ pyrolysis processes.
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