The Bohai and Yellow seas are marginal seas of the western North Pacific, characterized by coastal eutrophication and populated coastlines. In this work, six survey datasets collected between 2011 ...and 2018 were used to investigate the excess of dissolved inorganic nitrogen (DIN) related to soluble reactive phosphorus (SRP), referred to as N*, in the Bohai and Yellow seas. High N* of more than 5 μmol kg−1 occurred mostly in the Changjiang and Yellow River plumes and/or near the Jiangsu coast. Away from these river plumes and the Jiangsu coast, however, N* usually ranged from −2.5 to 1.0 μmol kg−1. Combining our field data and previously published data, we found that N* in the Bohai and Yellow seas increased in the 1990s and 2000s, likely caused by the combined effect of atmospheric nitrogen deposition increase and the Kuroshio N* rise. In the 2010s, however, the coastal N* increases stopped. Based on a N*-budgeting approach, marine N (either from in situ decomposition of marine organic matters or from the open seas via current inputs) and non-marine N (either from riverine inputs or from local atmospheric nitrogen deposition) were distinguished. Marine N accounted for 51% ± 38% of DIN in the Bohai Sea and 67% ± 37% of DIN in the Yellow Sea. Although this is a regional study, we suggest that accumulation of atmospheric nitrogen along oceanic circulation pathways dominates the decadal evolution of coastal eutrophication. These findings and new insights may improve management of eutrophication in these two important marginal seas, and will also improve our understanding of nutrient dynamics in other marine systems.
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•Marine N accounts for 51% of the Bohai Sea DIN and 67% of the Yellow Sea DIN.•Oceanic transport of atmospherically deposited N enhances coastal eutrophication.•Increases in excess nitrogen in the Bohai and Yellow seas stopped in the 2010s.
As the global concerns regarding climate change and the related environmental adversities continue to persist alongside rapid development of the world economies, the United Nations declared a set of ...compressive sustainable development goals (SDG) that are to be realized by the end of 2030. These goals are specifically conceptualized to collectively facilitate the attainment of sustainable socioeconomic development while concurrently improving the quality of the global environment. Hence, this study assesses the interlinkages between economic growth, environmental pollution, financial development, and renewable energy use in light of the objectives of SDG8, SDG13, SDG10, and SDG7 by considering the BRICS nations as a case study. Although the previous studies, in this regard, have predominantly focused on specifically scrutinizing the determinants of these four macroeconomic variables of concern, not much importance was shown to map the interrelationships among these variables. The econometric analysis conducted in this study utilizes quarterly frequency data covering the period from 1990‐Q1 to 2020‐Q4. Overall, the findings from causality and variance decomposition analyses reveal that in the long run these variables are influenced by each other which, in turn, also verifies the cross‐linkages between the four SDG of concern. Besides, the causality‐related findings appear to be robust when alternate causality estimators are employed. Therefore, based on these critically important causal relationships, a set of interactive SDG‐related policies is recommended.
This work describes the construction of a novel planar chiral 2.2paracyclophane-based thermally activated delayed fluorescence (TADF)-active molecule with circularly polarized luminescence (CPL). ...The combination of the bulky planar chiral phenoxazinephane (PXZp) donor based 2.2paracyclophane and triazine acceptor enables the highly efficient luminescence performances and excellent CPL properties. The enantiomers exhibit excellent TADF activities, the energy difference (ΔE ST) between singlet and triplet of the molecule is only 0.03 eV. Notably, through solution-process, a yellow CP-OLEDs based on the molecule as the emitting layers displays high maximum brightness (L max) up to 34 293 cd m–2, maximum external quantum efficiency (EQE max) up to 7.8% and remarkable CP-EL signal with g EL factor up to 4.6 × 10–3.
This article presents a sensitivity study on shape memory alloy (SMA)-based friction pendulum bearings (FPBs) for response control of a three-span continuous isolated bridge. The responses of the ...bridge isolated with SMA-based FPB system are compared with those of the bridge isolated with FPB system. The effectiveness of SMA-based FPB system for response control is investigated through a case study. Results show that the residual displacement and peak displacement can be effectively reduced without significantly increasing the base forces of the bridge piers. The SMA-based FPB system can provide reliable recentering and energy dissipation capabilities for bridges against near-fault earthquakes.
Human activities have significantly altered nitrogen (N) availability in most terrestrial ecosystems, with consequences for community composition and ecosystem functioning. Although studies of how ...changes in N availability affect biodiversity and community composition are relatively common, much less remains known about the effects of N inputs on the coupled biogeochemical cycling of N and phosphorus (P), and still fewer data exist regarding how increased N inputs affect the internal cycling of these two elements in plants. Nutrient resorption is an important driver of plant nutrient economies and of the quality of litter plants produce. Accordingly, resorption patterns have marked ecological implications for plant population and community fitness, as well as for ecosystem nutrient cycling. In a semiarid grassland in northern China, we studied the effects of a wide range of N inputs on foliar nutrient resorption of two dominant grasses, Leymus chinensis and Stipa grandis. After 4 years of treatments, N and P availability in soil and N and P concentrations in green and senesced grass leaves increased with increasing rates of N addition. Foliar N and P resorption significantly decreased along the N addition gradient, implying a resorption‐mediated, positive plant–soil feedback induced by N inputs. Furthermore, N : P resorption ratios were negatively correlated with the rates of N addition, indicating the sensitivity of plant N and P stoichiometry to N inputs. Taken together, the results demonstrate that N additions accelerate ecosystem uptake and turnover of both N and P in the temperate steppe and that N and P cycles are coupled in dynamic ways. The convergence of N and P resorption in response to N inputs emphasizes the importance of nutrient resorption as a pathway by which plants and ecosystems adjust in the face of increasing N availability.
The bandwidth of frequency-selective surface (FSS)-based absorber decreases when high permittivity material is used to reduce the thickness of the absorber. A solution of this thickness-bandwidth ...dilemma was presented by using resistive FSS layer and frequency-dispersive magnetic material (FDMM) in substrate. The FDMM was designed for a certain profile of complex permeability, and the FDMM substrate has both high permeability and permittivity for thickness reduction and near frequency-nondispersive input susceptance for bandwidth expanding at low frequencies. A 2.3 mm thick FSS-based FDMM absorber was designed and fabricated, which achieved a broad absorption band of 4-15 GHz (3.75:1) with -10 dB reflectivity. In terms of the same bandwidth ratio, the thickness of FSS-based FDMM absorber is only 0.031λ L against the thickness of 0.114λ L of conventional FSS-based absorber.
Abstract In this study, featuring di2.2paracyclophane (DpCp) amine derivatives as electron donors and 4‐(4,6‐diphenyl‐1,3,5‐triazin‐2‐yl)phenyl (Trz) as the electron acceptor, four thermally ...activated delayed fluorescence (TADF) molecules are disclosed. The C 2 symmetric molecules, DpCpN‐Trz and DpCpCz‐Trz, bearing a chair‐like planar chiral di2.2paracyclophane moiety, are obtained as optically pure enantiomers ( R/S )‐ C ‐DpCpN‐Trz and ( R/S )‐ C ‐DpCpCz‐Trz. And the compounds B ‐DpCpN‐Trz and B ‐DpCpCz‐Trz with a bridge‐like di2.2paracyclophane skeleton are meso ‐compounds, thus without optically activity. All emitters show blue emissions peaking from 464 to 485 nm, accompanied by high photoluminescence quantum efficiency (up to 93%). The enantiomers ( R/S )‐ C ‐DpCpN‐Trz and ( R/S )‐ C ‐DpCpCz‐Trz exhibit symmetric circularly polarized photoluminescence spectra with dissymmetry factors (| g PL |) ranging from 3.8 × 10 −4 to 6.7 × 10 −4 in toluene and films. The organic light‐emitting diodes (OLEDs) fabricated with these emitters achieve maximum external quantum efficiencies of up to 19.5%. Notably, the circularly polarized OLEDs (CP‐OLEDs) with ( R/S )‐ C ‐DpCpN‐Trz and ( R/S )‐ C ‐DpCpCz‐Trz demonstrate | g EL | factors of up to 7.6 × 10 −4 . This study demonstrates a feasible way to design TADF materials and enantiomers by incorporating DpCp derivatives for CP‐OLEDs.
A hierarchical core-shell heterostructure comprised of vertical and intercrossing ultrathin NiMn-LDHs nanosheets shell and slightly curly and tops tangled CuO nanowires core shows promising ...electrochemical storage properties.
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•A hierarchical NiMn-LDH@CuO/CF core-shell heterostructure was successfully prepared.•The hybrid comprises of vertical NiMn-LDHs shell and tops tangled CuO nanowires core.•The NiMn-LDH@CuO/CF electrode exhibits high capacitance of 6077 mF cm−2 at 2 mA cm−2.•The blue LED indicator can be lit up eight minutes by three ASCs connected in series.
Supercapacitors are attracting tremendous research interest because they are expected to achieve battery-level energy density while having long calendar life and short charging time. Ultrathin layered double hydroxide nanosheets (LDHs) are promising candidates as electrode materials for energy storage. Herein, we have successfully designed and synthesized a hierarchical NiMn-LDH@CuO/CF core-shell heterostructure which comprises a vertical and intercrossing ultrathin NiMn-LDHs nanosheets shell and a slightly curly and tops tangled CuO nanowires core. The synthesized NiMn-LDH@CuO/CF electrode exhibits a high areal capacitance of 6077 mF cm−2 (2430.8 F g−1) at a current density of 2 mA cm−2 (0.8 A g−1), which is significant higher than those of CF, Cu(OH)2/CF, CuO/CF, NiMn-LDH/CF and NiMn-LDH electrodes. Moreover, a superior cycling stability of 89.22% retention after 8000 cycles at a high current density of 50 mA cm−2 is observed and a low internal resistance Rs (0.584 Ω) can be achieved. Furthermore, an all solid-state asymmetric supercapacitor (ASC) device based on the as-synthesized hierarchical NiMn-LDH@CuO/CF core-shell heterostructure hybrid material as positive electrode and activated carbon as negative electrode is successfully fabricated and exhibits an energy density of 10.8 W h kg−1 at a power density of 100 W kg−1. Additionally, a LED indicator can be lit up for eight minutes when three ASCs are connected in series. The excellent electrochemical performances can be credited to the significant enhancement of the specific surface area, charge transport and mechanical stability resulted from the ultrathin LDH shell, the highly conductive CuO nanowires core-shell nanostructure. This strategy for the fabrication of hierarchical core-shell heterostructure could have enormous potential for applications in high performance energy storage devices.
Current events: A phosphorus‐doped, graphite layer catalyst without any metal residue has been developed that shows high electrocatalytic activity, long‐term stability, and excellent tolerance to ...cross‐over effects of methanol in the oxygen reduction reaction. The oxygen reduction current densities of the glassy carbon (GC) electrode modified by the P‐doped graphite (see red line in the picture) are much larger than those of the unmodified (blue line) and the GC electrode modified by a platinum–carbon catalyst (data not shown).
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