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Conductive polymers as one of the candidate materials with pseudocapacitor behavior have inspired wide attentions, because of their high conductivity, flexibility, low cost and excellent processability. However, the intrinsically poor cycling stability induced by the volume change over the doping/dedoping redox process limits their practical applications. Herein, we report the exploration of electrodes with robust cycling capacity for supercapacitors (SCs), which are rationally designed by coating conductive poly(3,4-ethylenedioxythiophene) (PEDOT) around free-standing SiC nanowires using an all-dry oxidative chemical vaper deposition (oCVD) method. The as-constructed SiC@PEDOT nanowire architecture enables a specific capacitance of 26.53 mF/cm2 at 0.2 mA/cm2, which is ~370% to that of SiC nanowire counterpart (7.04 mF/cm2). Moreover, their aqueous-based SCs exhibit robust cycling stability with 104% capacity retention after 10000 cycles, which is among the highest values achieved for PEDOT-based SCs.

Freestanding air cathode catalyst with exceptional catalytic bifunctions for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is highly desirable for exploring rechargeable Zn–air batteries (ZABs) with low cost and high reliability. Here, a facile and scalable approach is demonstrated to prepare efficient and robust freestanding cathode catalyst that consists of dispersed Fe3C nanoparticles, rich Fe-Nx/N-C species and carbon fibers networks with large specific surface area, which is based on one-pot in-situ coupling of Fe and N induced active sites within bacterial cellulose-derived carbon fibers networks. Its bifunctional activity parameter (ΔE) for ORR and OER is 0.79 V, superior to those of single Fe- or N- modulated counterparts, and comparable to the state-of-the-art Pt/C + RuO2 catalyst (0.79 V). This material can be directly used as freestanding and binder-free catalyst layer, and as-assembled ZABs exhibit a larger peak power density (173 mW cm−2), higher specific capacity (717 mA h g−1, 10 mA cm−2) and better cycle stability (negligible activity decay after 165 h charge/discharge cycles) than those of Pt/C + RuO2-based devices, representing their potential applications in advanced energy conversion systems.

Halide perovskite single crystals (HPSCs) provide a unique platform to study the optoelectronic properties of such emerging semiconductor materials, while the temperature induced crystal growth method often has an increased solute integration speed and/or unavoidable solute consumption, resulting in a soaring or slumping crystal growth rate of HPSCs. Here, we developed a universal and facile solvent-volatilization-limited-growth (SVG) strategy to finely control the crystal growth rate by the fine-control-valve for high quality crystal grown through solution processes. The grown HPSCs by SVG method exhibited a record low trap density of 2.8 × 108 cm−3 and a high charge carrier mobility-lifetime product (μτ product) of 0.021 cm2/V, indicating the excellent crystal quality. The crystal surface defects were further passivated by oxygen suppliers as Lewis base, which led to a reduction of surface leakage current by two times when using for low dose rate X-ray detection. Such HPSC X-ray detector displayed a high sensitivity of 1274 µC/(Gyair cm2) with a lowest detectable dose rate of 0.56 μGyair/s under 120 keV hard X-ray. Further applications including alloy composition analysis and metal flaw detection by HPSC detectors were also demonstrated, which not only shows the bright future for product quality inspection and non-destructive materials analysis, but also paves the way for growing high quality single crystals and fabricating polycrystalline films.

Attention mechanisms can extract salient features in images, which has been proven to be effective for person re-identification. However, focusing on the saliency of an image is not enough. On the one hand, the salient features extracted from the model are not necessarily the features needed, e.g., a similar background may also be mistaken as salient features; on the other hand, various salient features are often more conducive to improving the performance of the model. Based on this, in this paper, a model that has joint weak saliency and attention aware is proposed, which can obtain more complete global features by weakening saliency features. The model then obtains diversified saliency features via attention diversity to improve the performance of the model. Experiments on commonly used datasets prove the effectiveness of the proposed method.

Airborne mineral dust triggers ice formation in clouds and alters cloud microphysical properties by acting as ice-nucleating particles (INPs), potentially influencing weather and climate at regional and global scales. Anthropogenic pollution would modify natural mineral dust during the atmospheric transport process. However, the effects of anthropogenic pollution aging on the ice nucleation activity (INA) of mineral dust remain not well-understood. In this study, we investigated the immersion mode ice nucleation properties and particle chemical characterizations of collected size-resolved Asian dust samples (eight particle size classes ranging from 0.18 to 10.0 μm), and testified the chemical modification of aged dust particles via particle chemistry and morphology analyses including the mass concentrations of particulate matter, the water-soluble ion concentrations, the mental element concentrations, and single-particle morphology. The mass fraction of Ca

Atmospheric lead (Pb) pollution has attracted long-term and widespread concerns due to its high toxicity. The definite source identification of atmospheric Pb is the key step to mitigate this pollution. Here, we first report an overlooked source of atmospheric nanosized Pb particles using transmission electron microscopy and bulk sample analyses, finding that residential honeycomb briquette combustion emits large numbers of nanosized Pb-rich particles. We found that 33.7 ± 19.9 % of primary particles by number from residential honeycomb briquette combustion contains the crystalline Pb particles. These Pb-rich particles range in size from 14 to 956 nm with a mean diameter of 117 nm. Compared with raw coal chunks, honeycomb briquette combustion could emit less carbonaceous particles, but largely increase nanosized Pb particle emissions. This result is attributed to two key factors: (1) higher Pb content in honeycomb briquette (63.6 μg g

Currently, it still remains a grand challenge to enhance energy density of micro-supercapacitors (MSCs) without sacrificing power density, cycle life and other key performance. Herein, we reported the exploration of free-standing electrodes for MSCs based on quasi-aligned SiC nanowire arrays wrapped by ultrathin graphitic carbon film (SiC@C). Such rationally designed SiC@C architecture bring an optimal specific capacitance of 78.98 mF cm−2 at a current density of 0.2 mA cm−2, which was enhanced by more than 700% in comparison to that of pure SiC counterpart (9.56 mF cm−2). The aqueous-based MSCs exhibit a high specific capacitance, fast charge-discharge rate, excellent rate capability, and long-term cycling stability (94.1% capacity retention after 10000 charge-discharge cycles). The ionic-liquid-based MSCs had an extended operating voltage up to 2.6 V with an energy density up to 2.84 μW h cm−2 (at a power density of 65.1 μW cm−2), which was a new record of SiC-based SCs, and superior to most of those of nanowire-based MSCs in other material systems ever reported.

Large-scale SiC nanoarrays with well-aligned configurations have attracted wide attention due to their significance for exploring novel optoelectronic devices. However, their controlled growth, especially under mild conditions (e.g., under air conditions), is still a great challenge. In the present work, the effects of some critically important parameters on the electrochemical etching approach, such as surfactant content, electrolyte temperature, hydrochloric acid, and the duty ratio of employed pulse voltages, were investigated to determine their effects on the development of 4H–SiC nanoarrays. It was found that the optimization of these four experimental parameters could facilitate the etching of SiC nanoarrays with improved uniformity, modulated diameter and wall thickness, tunable etching rates, and tailored morphologies, leading to a controlled growth. The possible etching mechanisms for the formation of SiC nanoarrays under different etching conditions were proposed.

A controllable heat-driven swirling wind turbine system was integrated with a photovoltaics (PV) system for energy generation in a heat-collecting shed. This is a brand-new type of a wind energy generation system; and a helical three-blade structure in a vertical axis was introduced. The stationary pre-rotation vanes have a variable diameter and a helical twist angle of 225°. A numerical simulation was conducted to investigate the feasibility of a wind turbine blade structure for efficient energy output for industrial application. The computational fluid dynamics (CFD) tool OpenFOAM was used to simulate the operating conditions of the wind turbine. The findings illustrated the efficacy of the new system. The new helical blade structure is efficient for wind energy output of the turbine in a swirling wind field. The simulation under different heat source temperatures illustrated that an increase in heat source temperature could increase the output efficiency of the wind turbine energy system. The increment in output efficiency could be up to 19.07% when the temperature rises from 40 K to 80 K. The PV-swirling wind integrated system was shown to be more economical than a single solar photovoltaic system because its investment payoff period could be shortened by 2 years.

The oxidation of polycyclic aromatic hydrocarbons (PAHs) determines their lifetime, toxicity and consequent environmental and climate impacts. The residential solid fuel burning composes of a substantial fraction of PAH emissions; however, their oxidation rate is yet to be explicitly understood, which is complicated by the contrasting emission factors under different combustion conditions and their subsequent evolution in the atmosphere. Here we used a plume evolution chamber using ambient oxidants to simulate the evolution of residential solid fuel burning emissions under real-world solar radiation, and then to investigate the oxidation process of the emitted PAHs. Contrasting oxidation rate of PAHs was found to be influenced by particles with or without presence of substantial amount of black carbon (BC). In the flaming burning phase, which contained 46% of BC mass fraction and 8% of organic aerosol (OA) internally mixed with BC, the larger PAHs (with 4-7 rings) was rapidly oxidized 12% for every hour of evolution under solar radiation; however, the larger PAHs from smoldering phase tended to maintain unmodified during the evolution, when 95% of OA was externally mixed with only minor fraction of BC (5%). This may be ascribed to the complex morphology of BC, allowing more exposure for the internally-mixed OA to the oxidants; in contrast with those externally-mixed OA which was prone to be coated by condensed secondary substances. This raises an important consideration about the particle mixing state in influencing the oxidation of PAHs, particularly the coating on PAHs which may extend their lifetime and environmental impacts.

Conducting polymers are considered as an attractive option for energy storage system. In this paper, a unique quadruple thiophene-based polythiophene derivative (pPHBT) film was prepared through the electrochemical deposition from a star-shaped tri(bithiophene)benzene (PHBT). The electrodeposited pPHBT film may possess the microporous structure owing to the effective polymerization of star-shaped PHBT monomer. Also, the electrochemical, UV-vis and theoretical characterization of pPHBT film show that the oxidation reaction for this film should occur on the quadruple thiophene units. The unique structure of pPHBT may enable it with interesting electrochromic and energy storage properties. The pPHBT film shows the multicolor electrochromic character from yellow to green, and finally to blue color. The charging/discharging curves show that pPHBT film exhibits a high capacity of 96.7 mAh g−1, which is viewed as a high value among the reported p-doped conducting polymer energy storage materials. Besides, the pPHBT film shows more symmetrical charging-discharging curves and relatively better cycling stability than the linear-structure poly(bithiophene) film. The combination of these fascinating properties results in an intelligent energy storage device changes its color based on its charged state so that the state of charge can be monitored by simple visual inspection.

Summertime bulk and size-segregated cloud water samples were collected in 2014 at the summit of Mount Tai (Mt. Tai, 1534 m a.s.l.) in the North China Plain to investigate the concentrations, size distributions and stable carbon isotopic compositions (δ13C) of dicarboxylic acids, oxoacids and α-dicarbonyls as well as fluorescence properties of dissolved organic carbon (DOC). Positive correlations were observed for Peaks A (terrestrial humic-like), M (marine humic-like) and T (protein-like) with diacids and related compounds (r2 ≥ 0.43), except for Peak M and α-dicarbonyls, illustrating that fluorescent components and dicarboxylic acids were derived from common biological origins and biomass burning. Oxalic acid (C2, 2080 μg L−1) was the dominant diacid in this study, followed by succinic (C4, 640 μg L−1) and glyoxylic (ωC2, 448 μg L−1) acids. Compared to organic precursors, the relatively negative δ13C values of C2 (−18.8‰), glyoxylic acid (ωC2, –16.6‰), pyruvic acid (Pyr, −21.5‰) and methylglyoxal (MeGly, −19.6‰) supported that C2, Pyr, ωC2 and MeGly were formed via the oxidation of 13C-enriched organic precursors in aqueous phase. Furthermore, the larger size (22 μm) of cloud droplet was associated with more abundant organic compounds in general, which might be caused by scavenging ability and condensation of aerosol particles on the larger surface of large droplets. Our study suggested that high loadings of diacids and related compounds in cloud water over Mt. Tai were involved with emissions from anthropogenic and biological sources, followed by photochemical formation during the long-range atmospheric transport.

Using the structural priming paradigm, the present study investigates prosodic phrase priming with ERPs (event-related potentials). Participants listened to 2 consecutive Chinese ambiguous phrases that can be analyzed as a modifier-noun construction or as a narrative-object structure in both lexical judgment and structural judgment tasks. The results indicated that prosodic boundaries embedded in ambiguous phrases stably elicited the Closure Positive Shift (CPS). More importantly, the prosodic priming effect occurs, as evidenced by the fact that the amplitude of the CPS elicited by the target phrases was lower than that of the CPS elicited by the prime phrases. In addition, the priming effect was stronger in the structural judgment task than in the lexical judgment task. This result may suggest that prosodic priming was facilitated when the listener's attention was directed to the prosodic aspect and that under such circumstances listeners process the prosodic boundary deeply. In conclusion, prosodic phrase structures are formulated in the brain and modulate the processing of the immediately subsequent item during speech comprehension, and this process is influenced by the type of task being performed.

Silicon carbide (SiC) is recognized as one of the shining stars of third generation semiconductors, because of its preeminent characteristics, for instance, outstanding mechanical behavior, exceptional chemical inertness, high thermal stability, and high thermal conductivity, which represent its unique advantage and importance to be serviced under high-power/high-temperature/high-voltage harsh environments. In this review, we firstly present a comprehensive overview on the designed growth of one-dimensional (1D) SiC nanostructures in fruitful morphologies with tailored doping, followed by a detailed discussion to highlight a range of intriguing properties. Subsequently, the state-of-the-art research activities regarding their extensive applications are systematically summarized, including field emitters, supercapacitors, field-effect transistors, photocatalysts, pressure sensors, microwave absorption, superhydrophobic coating, and so forth. Finally, the future prospects and research directions of 1D SiC nanostructures are proposed.

Risks in the industrial operation processes involve complex system elements such as human, machine, organization, information, as well as nonlinear coupling relationships among them. Traditional risk analysis methods focus on the cause-effect relationships between the system elements and accidents, while ignoring what the correct and proper relationships should be. For a proactive risk identification and analysis, learning from success is suggested instead of learning from post hoc accidents, which requires that risk analysis identifies the normal functions and their couplings. Therefore, system functioning has been a subject of interest in the field of risk analysis. The Functional Resonance Analysis Method (FRAM) has been an effective tool to reveal the couplings and dependent relationships among different functions. However, the functions identification and interaction analysis in the FRAM is limited because there is no consistent or explicit stop rule. For a detailed and rigorous description of functions, the Accident Causation Analysis and Taxonomy (ACAT) model is used to enrich the FRAM by generating functions based on a closed-loop control system. Two operation processes in the hazardous industries are used as illustrations. The results show that more functional constraints and deep contributing factors to accidents can be identified with the hybrid approach.

Field observation data have shown that the actual wind speed and direction in an urban built environment always vary with time. Realizing the flow field simulation under time-varying inflows can have a great significance in fully understanding the airflow and the transportation of air pollutants in the atmospheric boundary layer. A new scheme based on the standard SIMPLE (Semi-Implicit Method for Pressure Linked Equations) algorithm has been implemented in OpenFOAM, named as TimeVarying-SIMPLE approach, to simulate the time-series airflow field under time-varying inflows in this study. The accuracy of TimeVarying-SIMPLE approach compared with PISO (Pressure-Implicit with Splitting of Operators) algorithm and PIMPLE (merged PISO-SIMPLE) algorithm was validated by solving the fully developed laminar flow in a straight pipe under sinusoidally varying inflow. The wind field and pollutant dispersion in an ideal street canyon with an aspect ratio of 1 under time-varying inflows were calculated using the TimeVarying-SIMPLE approach. The flows show an obvious flapping of the shear layer near the roof layer and the expansion or shrinkage of the main vortex under time-varying inflows, resulting in a significant increase of the removal efficiency of pollutants inside the street canyon compared to that under steady inflow. The average time of actual high-frequency wind speed data is critical to produce the time-varying inflows for the boundary conditions of numerical simulations, which could produce different simulated removal efficiency of pollutants inside the street canyon. The appropriate average time should be estimated by the pre-multiplied power spectrum of the measured high-frequency wind-speed data.

Complex systems often experience a long period of incubation before accidents occur. Therefore, a proactive risk assessment is essential for process safety. The conventional job hazard analysis (JHA) method has been an effective tool to conduct a process risk assessment in the high-risk industrial field. However, the conventional JHA is inadequate for the proactive risk assessment since it is usually conducted during and before one specific operation process. Operations such as startup and maintenance are performed repeatedly on the lifecycle of a plant. Therefore, the risk reduction measures for the industrial process should include not only preventive actions obtained from the conventional JHA but also recovery ones. Resilience engineering (RE) has proven to be helpful for the recovery analysis of a complex system. The objective of this paper is to propose a proactive and comprehensive process risk assessment approach based on JHA and RE. The mechanism of applying RE to address operation process risk is illustrated. The integrated approach can provide guidelines to establish proactive risk reduction measures as well as maintain a low-risk level. Finally, a gas transmission startup process risk assessment case is presented to demonstrate its applicability.

In this work, we report two isomers composed of 1-phenyl-1H-phenanthro[9,10-d]imidazole (PI), hydroxyl and tetraphenylethylene (TPE), abbreviated as m-PITPE and p-PITPE. It is found that they exhibit similar aggregation-induced emission (AIE) behavior but totally different excited-state intramolecular proton transfer (ESIPT) characteristic, as a result of the different linkage sites of PI on TPE moiety. Theoretical calculations and their different experimental responses to F− demonstrate that only the para-linkage isomer displays ESIPT. In m-PITPE with meta-linkage, the electron cloud distribution only locates at the TPE part in the singlet excited (S1) states, which results in the localized excited state without ESIPT characteristic.

Cyanostilbene has been widely used in the design of photoelectrical materials, and our previous work has confirmed its Z/E isomerization reaction under photoirradiation can be suppressed by forming a suitable donor-acceptor (D-A) structure. In this work, we report two D-A cyanostilbene derivatives with AIE activity, abbreviated as PZPNC and PZNC, whose chemical structures only differ by one more phenyl between donor and acceptor. Their Z/E isomers were characterized with single crystal structures and the impact of D-A distance on their stability of Z/E configuration was studied. The in-situ UV–vis spectra and HPLC results of Z/E-PZPNC and Z/E-PZNC under photoirradiation demonstrated that the Z/E isomerization reaction of PZNC was slower than PZPNC, indicating that the shorter D-A distance is conductive to the stability of cyanostilbene due to the relatively stronger charge transfer state with lower energy.

Nitrated phenols (NPs) are regarded as a major component of brown carbon and affect the earth environment. Previous studies have suggested that NPs in the atmosphere partially originate from coal combustion; however, the direct emissions have not been validated. In this study, the emissions of ten NPs from ten kinds of coal for residential use were investigated via laboratory combustion experiments in which PM2.5 samples were collected and analyzed by UHPLC-MS. The fine particulate NPs emitted from coal combustion were dominated by nitrocatechols and the methyl substituents under most conditions, while the emission profile of nitrated phenols varies with different rank of coals. Based on the emission ratios of NPs/PM2.5 obtained from this study and the PM2.5 emission factors in the literature, the emission factors of fine particulate NPs for chunks of lignite, bituminite, and anthracite and for briquettes of anthracite were calculated as 0.2–10.1 mg kg−1. According to the residential coal consumption in 30 provinces in China in 2016, the total emission of fine particulate NPs from the residential coal combustion was estimated to be 178 ± 42 Mg.

Aerosol samples were collected at Lin'an, a background site of Yangtze River Delta (YRD). Morphology, size, composition, and mixing state of individual aerosol particles were characterized by transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy (EDS), and the soluble ions of PM1.0 were studied by aerosol mass spectrometer (AMS). The daily average AMS mass concentrations of sulfate, nitrate, and ammonium were about 5.8, 8.6, and 5.6 μg/m3, respectively. Individual aerosol particles were classified into seven types: S-rich, K-rich, organic matter (OM), soot, fly ash, metal, and mineral. S-rich particles were dominant in all size bins, and 51% (by number) of S-rich particles were internally mixed with other particles. The fraction of organic coating particles was 13.7% in morning, 25.2% in afternoon, and 11% in evening, suggesting that the strong photochemical process during afternoon produced more secondary organic aerosols (SOA) on the surface of inorganic particles. Fly ash and metal particles were abundant during the day, suggesting the influence of emissions from coal-fired power plants and steel plants. The results indicate that the intense industrial emissions in the YRD significantly transported to the background areas. PM2.5 concentration may be lower in background air than in urban air but complex mixing state of aerosol particles indicates that the long-range transported particles substantially influenced the background air quality.

Microplastics (MPs), as an entirely anthropogenic type of pollution, are considered to be stratigraphic markers of the Anthropocene Epoch, and have become of increasing public concern over the past decade. Recent studies have revealed that the atmosphere is an efficient medium to disseminate MPs from their sources to remote mountains and marine areas. However, current research on atmospheric MPs (i.e. airborne MPs) is generally less highlighted than MP water and soil pollution studies due to the lack of standard methods for the identification and quantification of atmospheric MPs. This paper reviews the published literature on airborne MPs, gives an overview of the advantages and disadvantages of current airborne MPs collection techniques, extraction methods and identification (i.e., ‘passive’ and ‘active’ sampling, density separation and visual identification), and lays a foundation for future studies. The physical and chemical characteristics, classification, spatial and temporal scale distributions, sources, transport, and environmental impacts of airborne MPs are summarized. There are substantial research gaps in the quantification of airborne MPs and the exploration of toxicity mechanisms of inhalable MPs. The establishment of accredited methods is an urgent challenge for a better understanding on airborne MPs and their environmental and health effects. As one of the constituents in many aerosols, airborne MPs should be treated as a recognized pollutant for long-term monitoring, and the factors that specifically affect airborne MPs could be better addressed by means of the characterization of individual MPs. In the future, the effects and interaction of MPs in the atmosphere, lithosphere and hydrosphere are also of critical importance.