Search

Species abundance distribution (SAD) combines species richness with species abundance in a community and is an important indicator of community structure. Although many studies have applied mathematical models to fit the SADs of plant communities, there are still few studies on the changes in the shape of SAD (i.e., the skewness of the SAD curves) along the environmental gradient. Especially for forest communities, it is still unclear whether the model fitting and shape change of SADs are consistent in different vegetation types. Here, 28 plots of 20 m × 20 m were set up in Hynobius amjiensis National Nature Reserve according to the main forest vegetation types. The species composition and abundance of each species were surveyed in each plot. The logseries model and the lognormal model were fitted to the SAD in each plot, and then the best-fit model was selected based on the corrected Akaike's Information Criteria (AICc). The α value in Gambin model and the η value in Weibull model were calculated to reflect the shape of SAD in each plot. The λ value in Weibull model was calculated to reflect the scale of SAD (i.e., the range observed in abundance). The relationship between altitude and the shape and scale of SAD was analyzed. The results were as follows: (1) The logseries model fitted SAD better than the lognormal model. (2) When all plots were included, there was no significant correlation between SAD shape (α and η) and altitude, but there was a significant positive correlation between the λ value and altitude. (3) There was a negative correlation between altitude and α and η values in the mixed evergreen and deciduous broad-leaved forests, and there was a significant positive correlation between the α value and altitude in the deciduous broad-leaved forests, while there was no significant correlations between both α value and η value and altitude. The results indicate that the model fitting and shape change of SADs along the environmental gradient are related to the vegetation types of the forest community. Therefore, it is necessary to consider the vegetation types when analyzing the relationship between SAD and impact factors in plant communities.

The Great Xing'an Range (GXR) is a significant belt of polymetallic deposits located in the eastern segment of the Central Asian Orogenic Belt. The recently found Huoluotai porphyry Cu (Mo) deposit is situated in the northern GXR region in northeastern (NE) China. The deposit has been studied extensively using field geology and geochronological methods, which have identified two distinct mineralization events. These events include an early occurrence of porphyry-type Cu (Mo) mineralization and a later occurrence of vein-type Cu mineralization. Prior geochronology investigations have determined an approximate age of 147 Ma for the early porphyry-type Cu (Mo) mineralization. 40Ar/39Ar dating of K-feldspar of the altered Cu-mineralized quartz diorite porphyry veins for the overprinting vein-type Cu mineralization provides plateau ages of 123.1 ± 1.5 Ma, 122.3 ± 2.8 Ma, and 122.2 ± 0.4 Ma. Sulfide S-Pb isotope compositions of the two mineralization events suggest that both have a magmatic source. The origin of ore-forming metals displays the features of a crust–mantle mixing origin. The regional extensional tectonic setting in NE China during the Early Cretaceous was caused by large-scale lithosphere delamination and upwelling of the asthenospheric mantle. These processes were triggered by the rollback of the Paleo-Pacific Plate. The tectonic event in question resulted in the lithospheric thinning, significant magmatic activity, and mineralization in NE China. [ABSTRACT FROM AUTHOR]

The newly discovered Xiaohongshilazi deposit located in Panshi City, central Jilin Province, NE China, is a medium-scale Pb–Zn–(Ag) deposit. The Pb–Zn–(Ag) orebodies are divided into layered and vein-type orebodies, which have different ore geneses. The layered Pb–Zn orebodies are mainly hosted within and spatially controlled by the volcanic rocks. To constrain the age and tectonic setting of the layered Pb–Zn mineralization, we completed laser-ablation–ICP–MS zircon U–Pb dating and whole-rock major and trace element analyses of the ore-bearing volcanic rocks. The dacite samples were confirmed as belonging to the Daheshen Formation and were the main ore-bearing volcanic rocks for the layered orebodies. They yielded concordia U–Pb ages of 278.1 ± 1.8 Ma and 278.3 ± 1.8 Ma, respectively, indicating that the volcanic rocks from the Daheshen Formation and related layered Pb–Zn mineralization were formed in the early Permian. The andesite and rhyolite located above the layered orebodies yielded concordia U–Pb ages of 225.0 ± 1.1 Ma, 225.3 ± 1.5 Ma, and 224.7 ± 1.2 Ma, respectively; these substances are considered to be of the Sihetun Formation and were first reported in the area. The dacite samples associated with layered Pb–Zn mineralization were high in SiO2 (62.54–65.02 wt.%), enriched in LREEs and LILEs (e.g., Rb, Ba, and K), and showed depletion in HFSEs (e.g., P and Ti). It showed slightly negative Eu anomalies (δEu = 0.60–0.65) and negative Nb anomalies, with Th/Nb (1.12–1.21) and La/Nb (2.8–4.7) ratios, presenting subduction-related arc magma affinity formed in an active continental margin setting. In agreement with previous studies on zircon Hf isotopes (εHf (t) = +0.23~ +10.60) of the volcanic rocks from the Daheshen Formation, we infer that they were derived from the partial melting of the depleted lower crust. In conclusion, mineralization characteristics, geochronological data, geochemical features, and regional tectonic evolution suggest that two Pb–Zn–(Ag) mineralization stages from the Xiaohongshilazi deposit occurred: the layered VMS-type Pb–Zn mineralization associated with the marine volcanic rocks from the early Permian Daheshen Formation, which was induced by the subduction of the Paleo-Asian oceanic plate beneath the northern margin of the North China Craton, and the vein-type Pb–Zn–(Ag) mineralization caused by the subduction of the Paleo-Pacific Plate in the early Jurassic. Considering this, along with the mineralization characteristics of the same-type polymetallic deposits in this region, we propose that the early Permian marine volcanic rocks have great prospecting potential for the VMS-type Pb–Zn polymetallic deposits. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of CO2 (CO2RR) to high‐energy‐density C3 fuels like n‐propanol has been widely recognized as one of the core technologies for both renewable energy storage and carbon neutrality. Unfortunately, exceptional catalytic sites that are able to simultaneously implement efficient conversion to C1 and C2 products are difficult to design for single electrolyzers, leading to poor activity and selectivity toward n‐propanol. Alternatively, electroreduction of CO (CORR) has shown good performance toward C3 fuels, but the cost and safety of gas storage hinder its industrialization. Herein, a system consisting of two tandem electrolyzers for converting CO2 to CO and CO to n‐propanol, respectively, is constructed. Beyond the reported tandem electrodes and one‐pot tandem catalysts, precise voltage control over tandem electrolyzers enables optimizing the conversion of both CO2RR to CO and CORR to n‐propanol. Significantly, an unprecedented Faradaic efficiency of 15.9% for n‐propanol along with corresponding half‐cell power conversion efficiency of 19.3% is achieved. [ABSTRACT FROM AUTHOR]

Single site catalysts provide a unique platform for mimicking natural enzyme due to their tunable interaction between metal center and coordinated ligand. However, most works have focused on preparing structural and functional models of nature enzyme, with less reports also taking the local chemical environment, i.e., functional/catalytic residues around the active site which is an essential feature of enzymes, into consideration. Herein, we report a Co-centered porphyrinic polymer containing the enzyme-mimic micro-environment, where the linker triazole over CoN4 site enables formation of hydrogen bond with the *COOH intermediate, thus promoting the electrocatalytic reduction of CO2. As-prepared catalyst achieves the CO2-to-CO conversion of 5, 788 h−1 turnover frequency value and near unit (∼ 96%) faradaic efficiency at −0.61 V versus reversible hydrogen electrode. This strategy will bring new dimension of designing highly active single-site catalysts. [ABSTRACT FROM AUTHOR]

Selective electrochemical CO2 reduction to formic acid is an appealing strategy to achieve efficient utilization of CO2. Modification of the catalytic interface with organic linkers has been proven to promote the conversion of CO2 to CO, but the highly selective generation of formic acid is still a challenge. Herein, modification of the interface of graphene oxide (GO) with amide linkages to anchor SnO2 nanoparticles is presented to catalyze the CO2 reduction reaction (CO2RR). As expected, the as-synthesized SnO2/tert-GO shows a competitive high cathodic faradaic efficiency (FE) of 84.4% for formate at −0.96 V and shows long-term stability for the CO2RR. Further, density functional theory (DFT) calculations indicated that amide linkages facilitate the conversion of CO2 to formate. [ABSTRACT FROM AUTHOR]

As an environmentally friendly oxidant, H2O2 is widely utilized in various fields; however, its production methods remain limited to the chemical anthraquinone process. Alternatively, electrocatalytic oxygen reduction possesses numerous notable advantages (e.g., cost‐effectiveness, small‐scale, and distributed nature). As electrocatalytic oxygen reduction has been widely investigated in the fields of fuel cells and metal‐air batteries, the mechanism of the 2e−‐ORR pathway for producing H2O2 is not sufficiently clear. Herein, we explore the effect of the cobalt (Co) coordination environment on the electrochemical production of H2O2. The detailed investigation on N‐, P‐, and S‐coordinated Co catalysts (Co1N1N3, Co1P1N3, and Co1S1N3) demonstrates that changing the coordination environment evidently affects the H2O2 selectivity, and the S‐coordinated Co exhibits the best catalytic performance. This finding would lead to the design and selection of catalysts at atomic level for producing H2O2 via electrocatalytic oxygen reduction. [ABSTRACT FROM AUTHOR]

The metasedimentary Lujiapuzi Formation crops out along the northeastern margin of the North China Craton, close to the Yan‐Liao Rift. The age and tectonic setting of the formation, and its relationship with the Yan‐Liao Rift are currently unclear. Here we present detrital zircon U‐Pb ages, and Hf isotopic and geochemical data for the Lujiapuzi Formation to constrain the timing of deposition, the provenance of the formation, and the regional stratigraphy relationship. Zircon U‐Pb dating constrains the timing of deposition of the Lujiapuzi Formation to younger than 1780 Ma, and indicates that most grains were sourced from the Longgang Block and the Paleoproterozoic Liao‐Ji Belt. Detailed field investigations and a correlation of the regional stratigraphy reveal that much of the Lujiapuzi Formation is equivalent to the Tuanshanzi Formation in the Yan‐Liao Rift; the lower section may represent the earliest sediments deposited within the Fanhe Basin. Based on these results and the findings of previous studies, we suggest that the base of the Changcheng System has an age of 1.80 Ga. Zircon Hf isotopic data indicate that the main period of crustal growth along the northeastern margin of the North China Craton occurred at 3.2–2.5 Ga, with a peak at 2.9–2.7 Ga. [ABSTRACT FROM AUTHOR]