Different conformations, including planar, corrugated, as well as the deficient structure of the two-dimensional materials, play a relevant role in determining their catalytic reaction performances. ...Here, we systematically investigated the stabilities, electronic properties, and nitrogen activities capacity of various vacancy-modified g-C3N4 considering two different conformations (planar and corrugated) to explore the effects of nitrogen vacancy (NV) and conformations on the photocatalytic performance of g-C3N4 by means of density functional theory computations. Our results found that not only can the nitrogen vacancy (NV) promote separation efficiency of the photoinduced carriers in g-C3N4 but also the distortion conformation can activate more n → π* transitions of NV g-C3N4, resulting in a red shift of optical absorption spectra. More importantly, our results reveal that the corrugation configuration structure, compared to planar conformation, is much more favorable to photocatalytic nitrogen fixation reaction from the aspects of nitrogen absorption capacity and free-energy change, in which corrugation model with N2C vacancy has the smallest onset potential (1.32 V) for the most difficult step through the alternating pathway.
Nowadays, China's economy and energy structure are deeply adjusting to the direction of low-carbonization and non-carbonization with unprecedented efforts. This paper considered carbon emissions and ...energy endowments, adopted SBM-Undesirable model and spatial Durbin model to calculate the energy efficiency of 30 provinces and municipalities in China from 2015 to 2019 and analyze the direct effect, indirect effect and total effect on energy efficiency of 7 variables. Empirical results show that: Energy efficiency has spatial positive correlation and agglomeration characteristics; The main influencing factor of China's energy efficiency is energy consumption structure; Regions with strong energy endowment bear the environmental pollution cost of energy consumption areas in China; Environment Kuznets Curve (EKC) exists in China, but different provinces and municipalities are distributed in disparate stages; Research and development (R&D) investment only affects local energy efficiency, and has no spillover effect on surrounding areas in China; Foreign direct investment (FDI) has negative impacts on China's energy efficiency, and there is a phenomenon of pollution paradise. The valuable conclusions obtained in this study deepens the insights about the influencing factors of China's energy efficiency under the constraints of carbon emission and energy endowment.
Energy efficiency has spatial positive correlation and agglomeration characteristics; The main influencing factor of China's energy efficiency is energy consumption structure; Regions with strong energy endowment bear the environmental pollution cost of energy consumption areas in China; Environment Kuznets Curve (EKC) exists in China, but different provinces and municipalities are distributed in disparate stages; Research and development (R&D) investment only affects local energy efficiency, and has no spillover effect on surrounding areas in China; Foreign direct investment (FDI) has negative impacts on China's energy efficiency, and there is a phenomenon of pollution paradise. Display omitted
•Energy efficiency has spatial positive correlation and agglomeration characteristics.•Energy consumption structure mainly affects energy efficiency.•Environment Kuznets Curve exists in China.•"Pollution paradise hypothesis” exists in foreign direct investment.•Environmental pollution is transferred to surrounding provinces through resource trades.
Soluble N-ethylmaleimide—sensitive factor attachment protein receptor (SNARE) proteins drive membrane fusion by assembling into a four-helix bundle in a zippering process. Here, we used optical ...tweezers to observe in a cell-free reconstitution experiment in real time a long-sought SNARE assembly intermediate in which only the membrane-distal amino-terminal half of the bundle is assembled. Our findings support the zippering hypothesis, but suggest that zippering proceeds through three sequential binary switches, not continuously, in the amino- and carboxyl-terminal halves of the bundle and the linker domain. The half-zippered intermediate was stabilized by externally applied force that mimicked the repulsion between apposed membranes being forced to fuse. This intermediate then rapidly and forcefully zippered, delivering free energy of 36 k B T (where k B is Boltzmann's constant and T is temperature) to mediate fusion.
When ascorbic acid is administered, it is oxidized at the surface of the monitor, resulting in the release of an electron and negative charge. ...high-dosage intravenous ascorbic acid could yield ...false hyperglycemia measured by POC devices, which has been documented in burn patients receiving intravenous vitamin C infusions (66 mg/kg/h) 4. ...when initiating high-dose vitamin C, physicians should be aware of the potential consequences of pseudohyperglycemia if employing POC devices for glucose monitoring. Effect of vitamin C infusion on organ failure and biomarkers of inflammation and vascular injury in patients with sepsis and severe acute respiratory failure: the CITRIS-ALI randomized clinical trial.
Unlike inorganic crystals, metal-organic frameworks do not have a well-developed nanostructure library, and establishing their appropriately diverse and complex architectures remains a major ...challenge. Here, we demonstrate a general route to control metal-organic framework structure by a solvent-assisted ligand exchange approach. Thirteen different types of metal-organic framework structures have been prepared successfully. To demonstrate a proof of concept application, we used the obtained metal-organic framework materials as precursors for synthesizing nanoporous carbons and investigated their electrochemical Na
storage properties. Due to the unique architecture, the one-dimensional nanoporous carbon derived from double-shelled ZnCo bimetallic zeolitic imidazolate framework nanotubes exhibits high specific capacity as well as superior rate capability and cycling stability. Our study offers an avenue for the controllable preparation of well-designed meta-organic framework structures and their derivatives, which would further broaden the application opportunities of metal-organic framework materials.
Air quality directly relates to human health and economic and social sustainable development. This study collected the meteorological data of Beijing from November 1, 2013 to October 31, 2017, ...employed vector autoregression (VAR) model, Granger causality test, impulse response function and variance decomposition to explore the dynamic effects of average humidity, extreme wind speed, sunshine duration, average wind speed and rainfall capacity on air quality index (AQI). The results indicated that the air pollution in Beijing was mainly a self-aggregation and self-diffusion process, the self-cumulative effect accounted for around 88.9318% during 5 periods, once the diffusion conditions of air pollution worsen, air pollution would be formed within 3 days. Meteorological conditions, especially extreme wind speed, sunshine duration and average humidity affected the concentration and spatial-temporal distribution of air pollutant. Extreme wind speed as atmospheric dynamic factor rather than average wind speed was the most important meteorological element influencing the AQI change in Beijing, which caused more atmospheric motion and turbulence, improving the diffusion and dilution ability of air pollutant, whose self-cumulative influence was around 7.5270% during 5 periods. Sunshine duration as atmospheric thermal factor was the secondary important meteorological element affecting AQI change in Beijing for it was associated with the formation of temperature stratification and inversion, the self-cumulative effect accounted for around 2.1402% during 4 periods. This study deepens the insights about the formation and diffusion mechanism of air pollution in Beijing, introduces nontraditional methods to review traditional issue and draw valuable conclusions. Other natural or human action factor should be further analyzed in the future research.
Air pollution in Beijing was mainly a self-aggregation and self-diffusion process.
Extreme wind speed as atmospheric dynamic factor rather than average wind speed was the most important meteorological element influencing the AQI change in Beijing.
Sunshine duration as atmospheric thermal factor was the secondary important meteorological element affecting AQI change in Beijing.
Average wind speed and rainfall capacity had no significant impacts on air quality. Display omitted
•Air pollution in Beijing is mainly a self-aggregation and self-diffusion process.•Meteorological variables affect concentration and distribution of air pollutant.•Extreme wind speed is the most important meteorological dynamic factor.•Sunshine duration is the secondary importance meteorological thermal factor.•Average wind speed and rainfall capacity have no impact on air quality.
Surface-enhanced Raman scattering (SERS) analysis of environmental hydrophobic pollutants without chemical functionalization of a bare nanoparticle (NP) substrate presents a challenge. The motivation ...for our study is to develop a highly reproducible and robust portable SERS sensor for detection and identification of polycyclic aromatic hydrocarbons (PAHs) using bare Au NPs. Our hypothesis is that the coffee ring effect could separate PAHs from the bulk solution and concentrate them on the closely packed Au NP ring, consequently enhancing their Raman scattering. This premise was confirmed with the commonly used citrate-reduced Au NPs in 20 nm, having no structural uniqueness. Because of the coffee ring effect, however, closely packed but not aggregated Au NP arrays were formed and, consequently, facilitated the separation and concentration of hydrophobic PAHs. As a result, a prominent SERS enhancement can be obtained on the ring because of the electromagnetic mechanism. A mixture of six PAHs with different numbers of benzene rings, namely, naphthalene, anthracene, pyrene, benzoapyrene, benzog,h,iperylene, and indeno1,2,3-cdpyrene, could be readily identified in river water. This portable SERS sensor based on the coffee ring effect provides a robust and versatile approach in PAH detection without the need for stringent structural requirements for Au NPs.
Analysis of the changes of microorganisms during Chinese Feng-flavor Daqu fermentation, and the specific contribution of different environmental factors to Daqu microorganisms. High throughput ...sequencing technology and SourceTracker software were used to analyze the microbial diversity of Feng-flavor Daqu before and after fermentation. 85 fungal and 105 bacterial were detected in the newly pressed Feng-flavor Daqu, while 33 fungal and 50 bacterial in the mature Daqu, and 202 fungal and 555 bacterial in the environmental samples. After fermentation, the microbial community structure of Daqu changed and decreased significantly. 94.7% of fungi come from raw materials and 1.8% from outdoor ground, 60.95% of bacteria come from indoor ground, 20.44% from raw materials, and 8.98% from tools. By comparing the changes of microorganisms in Daqu before and after fermentation, the microorganisms in mature Daqu may mainly come from not only the enhanced strains but also the environment.The source of main microorganisms in Feng-flavor Daqu and the influence of environmental factors on the quality of Daqu were clarified, which provided a basis for improving the quality of Feng-flavor Daqu.
•Porous GO/CMC monoliths were prepared by a unidirectional freeze-drying method.•The incorporation of GO increased the compressive strength of the GO/CMC monoliths.•The porous GO/CMC monoliths ...exhibited a strong ability to absorb metal ions.•Ni@GO/CMC monoliths could catalyze the reduction of 4-nitrophenol to 4-aminophenol.
Orderly porous graphene oxide/carboxymethyl cellulose (GO/CMC) monoliths were prepared by a unidirectional freeze-drying method. The porous monoliths were characterized by Fourier transform infrared spectra, X-ray diffraction and scanning electron microscopy. Their properties including compressive strength and moisture adsorption were measured. The incorporation of GO changed the porous structure of the GO/CMC monoliths and significantly increased their compressive strength. The porous GO/CMC monoliths exhibited a strong ability to adsorb metal ions, and the Ni2+ ions adsorbed on GO/CMC monolith were reduced by NaBH4 to obtain Ni GO/CMC monolith which could be used as catalyst in the reduction of 4-nitrophenol to 4-aminophenol. Since CMC is biodegradable and non-toxic, the porous GO/CMC monoliths are potential environmental adsorbents.
Inorganic cesium lead halide perovskites, as alternative light absorbers for organic–inorganic hybrid perovskite solar cells, have attracted more and more attention due to their superb thermal ...stability for photovoltaic applications. However, the humid air instability of CsPbI2Br perovskite solar cells (PSCs) hinders their further development. The optoelectronic properties of CsPbI2Br films are closely related to the quality of films, so preparing high-quality perovskite films is crucial for fabricating high-performance PSCs. For the first time, we demonstrate that the regulation of ambient temperature of the dry air in the glovebox is able to control the growth of CsPbI2Br crystals and further optimize the morphology of CsPbI2Br film. Through controlling the ambient air temperature assisted crystallization, high-quality CsPbI2Br films are obtained, with advantages such as larger crystalline grains, negligible crystal boundaries, absence of pinholes, lower defect density, and faster carrier mobility. Accordingly, the PSCs based on as-prepared CsPbI2Br film achieve a power conversion efficiency of 15.5% (the maximum stabilized power output of 15.02%). Moreover, the optimized CsPbI2Br films show excellent robustness against moisture and oxygen and maintain the photovoltaic dark phase after 3 h aging in an air atmosphere at room temperature and 35% relative humidity (R.H.). In comparison, the pristine films are completely converted to the yellow phase in 1.5 h.
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