Abstract
Replacing sluggish oxygen evolution reaction (OER) with hydrazine oxidation reaction (HzOR) to produce hydrogen has been considered as a more energy-efficient strategy than water splitting. ...However, the relatively high cell voltage in two-electrode system and the required external electric power hinder its scalable applications, especially in mobile devices. Herein, we report a bifunctional P, W co-doped Co
3
N nanowire array electrode with remarkable catalytic activity towards both HzOR (−55 mV at 10 mA cm
−2
) and hydrogen evolution reaction (HER, −41 mV at 10 mA cm
−2
). Inspiringly, a record low cell voltage of 28 mV is required to achieve 10 mA cm
−2
in two-electrode system. DFT calculations decipher that the doping optimized H* adsorption/desorption and dehydrogenation kinetics could be the underlying mechanism. Importantly, a self-powered H
2
production system by integrating a direct hydrazine fuel cell with a hydrazine splitting electrolyzer can achieve a decent rate of 1.25 mmol h
−1
at room temperature.
Based on a transverse electric (TE)/transverse magnetic (TM) polarization diversity waveguide, we theoretically propose a TE-pass/TM-stop polarizer by etching a polarization dependent Bragg grating ...into the oxide layer of a silicon/thin SiO 2 gap/metal cap hybrid plasmonic waveguide. The simulation results indicate that the device is characterized by high TE-transmission and large TM-reflection levels in a wide waveband from 1.48 to 1.7 μm combined with an excellent compactness (length less than 5 μm). Transmission and reflection extinction ratio are both larger than 17.1 dB in the 1.48-1.64 μm wavelength range, while losses are smaller than 1.36 and 0.69 dB for the TE and TM modes, respectively.
Air layer on superhydrophobic surface underwater Sheng, Xianliang; Zhang, Jihua
Colloids and surfaces. A, Physicochemical and engineering aspects,
03/2011, Letnik:
377, Številka:
1
Journal Article
Recenzirano
Display omitted
► An air layer is seen on underwater lotus surface without additional pressure. ► The external pressure is a key to sustain “air layer effect” on lotus surface. ► The state of air ...layer on underwater lotus surface is monitored by contact angles. ► The microstructures on lotus surfaces are important for its air layer underwater.
Sustaining an air layer on superhydrophobic surface is known necessary for the applications of the “air layer effect” underwater on basis of previous literatures. However, the air layer becomes unstable when put underwater and even disappears when the hydraulic pressure increases. Thus much attention has been focused on the sustainability of an air layer on a superhydrophobic surface. This article studies the sustainability of the air layer on the surface of a lotus leaf by applying external pressure on the surface, which is a direct method to measure the sustainability of the air layer. It is displayed that the hydraulic pressure is a key factor to sustain an air layer on a superhydrophobic surface. Maintaining a certain amount of hydraulic pressure is necessary to sustain an air layer on a superhydrophobic surface, which may be important for the low drag or friction reduction of a superhydrophobic surface underwater. Therefore, we believe that the micro-designs of superhydrophobic surface which is capable of the “air layer effect” underwater should be connected with hydraulic pressure applied on it.
Abstract
Brazilian split experiments were carried out on coarse sandstone, obtained from a coal seam roof passed by the Shihuoshan tunnel in Xinjiang, and treated at different temperatures (room ...temperature 25 °C and high temperature 100 °C ~ 900 °C). The physical and mechanical characteristics of the samples were studied. The results showed that: after heat treatment, the color of the coarse sandstone samples gradually changed from dark gray to brownish red-pink; the higher the treatment temperature was, the darker the sample color. Microcracks and mineral composition changes occured in the coarse sandstone samples after heat treatment, which decreased the longitudinal wave velocity of the samples. The longitudinal wave velocity of the coarse sandstone samples decreased as a quadratic function of the treatment temperature. With the increase in longitudinal wave velocity, the tensile strength of the samples first increased and then decreased, changing as a quadratic function relationship. After heat treatment, the tensile stress–strain curve of the coarse sandstone could be divided into compaction, elasticity, plasticity, and failure stages. The energy was continuously accumulated in the coarse sandstone before its failure, and it was released suddenly after the failure. With increasing treatment temperature, the cumulative energy in the prepeak stages first increased and then decreased, reaching a maximum value at 500 °C. The prepeak energy and tensile strength of the coarse sandstone samples satisfied a linear function fitting relationship, indicating that a higher tensile strength in the coarse sandstone, led to more accumulated energy in the samples.
With the popularization of natural gas and the requirement of environmental protection, the development and utilization of natural gas are particularly important. The status of natural gas in China’s ...oil and gas exploration and development is constantly improving, and the country pays more and more attention to the exploitation and utilization of natural gas. The tight sandstone of Upper Paleozoic in Ordos Basin has the characteristics of low porosity, low permeability, and large area of concealed gas reservoirs. With the increasing demand for natural gas in China, systematic analysis and research on the geological conditions and enrichment law of large area gas reservoirs of tight sandstone of Upper Paleozoic in Ordos Basin to guide exploration and production also pose a great challenge to the current level of natural gas exploration and development in China. In order to solve this problem, this paper takes the Upper Paleozoic tight sandstone in Hangjinqi area in the north of Ordos Basin as the research object, summarizes the natural gas accumulation conditions of tight sandstone according to the geological characteristics of Ordos Basin, determines the main control factors of gas accumulation by superposition method in combination with the distribution characteristics of natural gas, simulates the dynamic process of gas accumulation, establishes the gas accumulation model, analyzes the conditions of gas accumulation and enrichment by statistical methods, summarizes the accumulation and enrichment rules of natural gas, and predicts the favorable exploration areas for natural gas. The results show that the relationship between hydrocarbon source rocks, traps, migration and transportation, and other reservoir-forming conditions and the distribution characteristics of natural gas is summarized, and the main controlling factors of reservoir-forming are determined by superposition method. We simulate the evolution process of faults, strata, oil, gas, and water flows in the study area and establish the dynamic reservoir-forming process of natural gas. By combining the reserve data with the reservoir source distance, reservoir facies type, and gas filling times, the reservoir-forming and enrichment conditions are studied by statistical analysis method, and the reservoir-forming and enrichment rules are summarized by combining the main controlling factors. The enrichment of natural gas is controlled by the development degree of source rocks, favorable tight sandstone combination, confluence channel, and local structure. According to the law of accumulation and enrichment, the division standards of favorable areas in different horizons are established, and the favorable exploration areas in the study area are predicted. The results provide theoretical data support for natural gas exploration in the study area.
ObjectiveTo accurately estimate the global prevalence of non-tuberculous mycobacteria (NTM) in adults with non-cystic fibrosis (non-CF) bronchiectasis and to determine the proportion of NTM species ...and subspecies in clinical patients from 2006 to 2021.DesignSystematic review and meta-analysis using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.Data sourcesMedline, Embase, Cochrane Library and Web of Science were searched for articles published between 2006 and 2021.Eligibility criteria for selecting studiesWe included all the prospective or retrospective studies without language restrictions and all patients were adults (≥18 years of age) with non-CF bronchiectasis. The studies estimated the effect size of the prevalence of NTM with a sample size ≥40, and patients were registered in and after 2006.Data extraction and synthesisTwo reviewers screened the titles, abstracts and full texts independently. Relevant information was extracted and curated into tables. Risk of bias was evaluated following the Cochrane Collaboration’s tool. Meta-analysis was performed with software R Statistics V.3.6.3 using random effect model with 95% CI. I2 index and Q statistics were calculated to assess the heterogeneity, and mixed-effects meta-regression analyses were performed to identify the sources of heterogeneity. The proportions of NTM subspecies were examined using Shapiro-Wilk normality test in R.ResultsOf all the 2014 studies yielded, 24 met the inclusion criteria. Of these, 14 were identified to be randomised controlled studies and included for an accurate estimation. The global prevalence of NTM in adults with non-CF bronchiectasis from 2006 to 2021 was estimated to be approximately 10%, with great variations primarily due to geographical location. Mycobacterium avium complex was the most common subspecies, followed by Mycobacterium simiae and Mycobacterium gordonae.ConclusionsThe prevalence of NTM in adults with non-CF bronchiectasis has been on the rise and the most common subspecies changed greatly in recent years. More cohort studies should be done in many countries and regions for future estimates.PROSPERO registration numberCRD42020168473.
Dielectric materials with high dielectric constant and breakdown voltage are very promising for pulsed energy storage applications. In this paper, (1-x) BaTiO3-xBiYO3 (x=0–0.5) ceramics were ...synthesized using conventional solid-state reaction method. The ceramic structure transformed from ferroelectric tetragonal phases (x≤0.5) to pseudo-cubic phases (x≥0.1). When x=0.2, beyond the solid solubility limit of BaTiO3-BiYO3, the second phase and glassy phases were formed, accompanying lattice parameter excursion. It revealed a gradual change from classic ferroelectric behavior in pure BaTiO3 to highly diffusive and dispersive relaxor-like characteristics with BiYO3 content increasing. It exhibited high polarization maximum and low remnant polarization, which was favorable for energy storage in (1-x)BaTiO3-xBiYO3 ceramics, due to the disrupted long polarization, the created weak coupling and the formed second phase. Furthermore, the nonlinearity of the (1-x)BaTiO3-xBiYO3 ceramics were weakened obviously. A maximum energy storage density of 0.316J/cm3 at 66kV/cm with relative high energy efficiency of 82.7% was achieved in 0.8BaTiO3-0.2BiYO3 ceramic, which indicated that (1-x)BaTiO3-xBiYO3 ceramics were promising lead-free relaxor materials for energy storage applications.
Obstructive sleep apnea (OSA) is an upper airway disorder occurring during sleep and is associated with atherosclerosis (AS). AS is a cardiovascular disease caused by environmental and genetic ...factors, with a high global mortality rate. This study investigated common pathways and potential biomarkers of OSA and AS. Microarray data were downloaded from the Gene Expression Omnibus (GEO) database and used to screen for differentially expressed genes (DEGs) in the OSA and AS datasets. A weighted gene co-expression network analysis (WGCNA) was used to identify the co-expression modules of OSA and AS. The least absolute shrinkage and selection operators (LASSO) were used to determine critical biomarkers. Immune cell infiltration analysis was used to investigate the correlation between immune cell infiltration and common biomarkers of OSA and AS. Results revealed that differentially expressed genes may be involved in inflammatory processes, chemokine signaling pathways, and molecular changes in cell adhesion. ERBB receptor feedback inhibitor 1 (ERRFI1) was the best-shared biomarker for OSA and AS. Immune infiltration analysis showed that ERRFI1 expression was correlated with immune cell changes. Changes in immune pathways, inflammatory processes, and cell adhesion molecules may underlie the pathogenesis of both diseases, and ERRFI1 may be a potential diagnostic marker for patients with OSA and AS.
The high dewetting abilities of lotus leaves can be transited to a complete wetting state by soaking the leaves in water at a depth of 50 cm for 2 h. However, after being dried by N2 gas, the high ...dewetting behavior of lotus leaves may be mostly restored. This indicates that experimental procedure might considerably affect the dewetting abilities of lotus leaves. To discover the mechanism underlying this interesting dewetting phenomena, the dewetting force was used to characterize the dewetting abilities of surfaces, and model studies to mimic the papillae were done. Surface hydrophobicity, sizes, rise angles, and secondary structures of the models’ sides affected their dewetting force with water. So we suggested that the dewetting states, Cassie or Wenzel’s state, of lotus surfaces depend much on the depth of water, i.e., the hydraulic pressure. On the other hand, the primary structures of papillae in Cassie’s state led to a high receding angle with respect to the plane of the leaf during the dewetting measurement. The secondary structures and micro/nano arrays of papillae increased the dewetting abilities of lotus leaves, since no water intruded between papillae. However, the structures of papillae in Wenzle’s state significantly reduced the dewetting abilities of lotus leaves after being soaked at a depth of 50 cm for 2 h. Therefore, as for novel designs of microdevices floating on water, including the use of the high dewetting properties of suphydrophobic materials, surface (primary or secondary) microstructure and external pressure, such as static hydraulic pressure, must be taken into account.
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