Experimental Study on Ratio and Performance of Coal Gangue/Bottom Ash Geopolymer Double-Liquid Grouting Material

Mine grouting reinforcement and water plugging projects often require large amounts of grouting materials.To reduce the carbon emission of grouting material production,improve the utilization of solid waste from mining enterprises,and meet the needs of mine reinforcement and seepage control,a double-liquid grouting material containing a high admixture of coal gangue powder/bottom ash geopolymer was studied.The setting time,fluidity,bleeding rate,and mechanical properties of grouting materials were studied through laboratory tests,and SEM analyzed the microstructure of the materials.The results show that the total mixture of calcined gangue does not exceed 60%.And the proportion of bottom ash replacing cement should be within 30%.At the same time,the volume mixture of sodium silicate is 20%.And the water-solid ratio does not exceed 0.6.The stability of the slurry prepared under this ratio is good.The microstructure of the stone body is dense,and its strength can meet the requirements of rock reinforcement and seepage control.Its economic and environmental benefits are more significant than the traditional cement-silicate double-liquid grouting material.

The Assessment of Global Surface Temperature Change from 1850s:The C-LSAT2.0 Ensemble and the CMST-Interim Datasets

Based on C-LSAT2.0,using high-and low-frequency components reconstruction methods,combined with observation constraint masking,a reconstructed C-LSAT2.0 with 756 ensemble members from the 1850s to 2018 has been developed.These ensemble versions have been merged with the ERSSTv5 ensemble dataset,and an upgraded version of the CMSTInterim dataset with 5°×5°resolution has been developed.The CMST-Interim dataset has significantly improved the coverage rate of global surface temperature data.After reconstruction,the data coverage before 1950 increased from 78%−81%of the original CMST to 81%−89%.The total coverage after 1955 reached about 93%,including more than 98%in the Northern Hemisphere and 81%−89%in the Southern Hemisphere.Through the reconstruction ensemble experiments with different parameters,a good basis is provided for more systematic uncertainty assessment of C-LSAT2.0 and CMSTInterim.In comparison with the original CMST,the global mean surface temperatures are estimated to be cooler in the second half of 19th century and warmer during the 21st century,which shows that the global warming trend is further amplified.The global warming trends are updated from 0.085±0.004℃(10 yr)^(–1)and 0.128±0.006℃(10 yr)^(–1)to 0.089±0.004℃(10 yr)^(–1)and 0.137±0.007℃(10 yr)^(–1),respectively,since the start and the second half of 20th century.

Spatiotemporal dynamics of population density in China using nighttime light and geographic weighted regression method

The distribution and dynamic changes of regional or national population data with long time series are very important for regional planning,resource allocation,government decision-making,disaster assessment,ecological protection,and other sustainability research.However,the existing population datasets such as LandScan and WorldPop all provide data from 2000 with limited time series,while GHS-POP only utilizes land use data with limited accuracy.In view of the limited remote sensing images of long time series,it is necessary to combine existing multi-source remote sensing data for population spatialization research.In this research,we developed a nighttime light desaturation index(NTLDI).Through the cross-sensor calibration model based on an autoencoder convolutional neural network,the NTLDl was calibrated with the same period Visible Infrared Imaging Radiometer Suite Day/Night Band(VIRS-DNB)data.Then,the geographically weighted regression method is used to determine the population density of China from 1990 to 2020 based on the long time series NTL.Furthermore,the change characteristics and the driving factors of China's population spatial distribution are analyzed.The large-scale,long-term population spatialization results obtained in this study are of great significance in government planning and decision-making,disaster assessment,resource allocation,and other aspects.

A reference-grade genome assembly for Astragalus mongholicus and insights into the biosynthesis and high accumulation of triterpenoids and flavonoids in its roots

Astragalus membranaceus var.mongholicus(AMM),a member of the Leguminosae,is one of the most important medicinal plants worldwide.The dried roots of AMM have a wide range of pharmacological effects and are a traditional Chinese medicine.Here,we report the first chromosome-level reference genome of AMM,comprising nine pseudochromosomes with a total size of 1.47 Gb and 27868 protein-encoding genes.Comparative genomic analysis reveals that AMM has not experienced an independent wholegenome duplication(WGD)event after the WGD event shared by the Papilionoideae species.Analysis of long terminal repeat retrotransposons suggests a recent burst of these elements at approximately 0.13 million years ago,which may explain the large size of the AMM genome.Multiple gene families involved in the biosynthesis of triterpenoids and flavonoids were expanded,and our data indicate that tandemduplication has been the main driver for expansion of these families.Among the expanded families,the phenylalanine ammonia-lyase gene family was primarily expressed in the roots of AMM,suggesting their roles in the biosynthesis of phenylpropanoid compounds.The functional versatility of 2,3-oxidosqualene cyclase genes in cluster Ⅲ may play a critical role in the diversification of triterpenoids in AMM.Our findings provide novel insights into triterpenoid and flavonoid biosynthesis and can facilitate future research on the genetics and medical applications of AMM.

19世纪80年代以来全球温度变暖趋势一致性进一步加强

升级了新的1850年以来的全球陆地气温数据集(C-LSAT2.0),结合美国NOAA/NCEI研发的ERSSTv5,将全球表面温度(CMST)观测数据集延长至1854~2019年,为全球气候变化研究提供了一个新的基准数据.对比发现,基于CMST的全球温度变化序列在1880年以前略高于其他几个全球序列,差异主要来源于采用不同海温数据所致,各个序列之间存在结构性不确定性;1880年之后, 5个全球表面温度观测序列的一致性非常高,并有显著一致的变暖趋势,具有高可靠性.基于C-LSAT2.0和CMST,对1880~2019年全球变暖趋势进行了估计,结果表明:近140年, 120年, 60年和40年陆地平均气温增暖趋势分别为:0.103±0.016, 0.115±0.020, 0.252±0.035和0.293±0.055°C/10 a;全球表面温度增暖趋势分别为:0.072±0.010, 0.084±0.011, 0.150±0.019和0.185±0.032°C/10 a.对1900~2018年全球年均温度EOF分析表明,前两个特征向量明显地反映了全球温度变化的主要模态:即全球一致升温模态和与太平洋年代际振荡(IPO)密切相关的模态.说明近120年全球温度变化主要由外部强迫(人类活动)和自然变率(IPO)控制.

Rapid and Scalable Synthesis of Prussian Blue Analogue Nanocubes for Electrocatalytic Water Oxidation

Design and fabrication of earth-abundant electrocatalysts for oxygen evolution reaction(OER)is essential in improving the overall ef-ficiency of water electrolysis.In this work,we proposed a rapid and scalable synthesis route for fabricating Prussian blue analogue(PBA)nano cubes with tun able compositi ons and uniform particle size.With the structural ben efits of abu ndant surface sites,facile charge transfer behavior and favorable Co^(2+)-to-Co^(3+)pre-oxidation reaction,fast generation and accumulation of the catalytically active Co3+sites can be achieved for the CoCo PBA nano cubes,leadi ng to remarkable OER activity with simulta neously achieved low overpotential,large anodic current density,small Tafel slope as well as outstanding intrinsic activity.Of note,by performing Iong-term OER operati on,the CoCo PBA nano cubes exhibit a remarkable 5.5-folds performs nee enhan ceme nt,and obvious surface rec on struc-tion and the accumulation of high-valence Co species can be identified,proving the crucial role of pre-oxidation process in boosting the OER catalysis.This work proposed a un iversal approach for the rapid,scalable and con trollable fabricati on of the PBA-based materials,and the elucidation of the pre-oxidation process in facilitating the OER catalysis may provide useful guidanee for designing and optimizing advanced catalysts for energy-related electro-oxidation reactions in the future.

Lanthanum-dopedα-Ni(OH)_(2)1D-2D-3D hierarchical nanostructures for robust bifunctional electro-oxidation

The development of advanced electrocatalysts for electro-oxidation reactions has attracted much attention because of the critical role of such electrocatalysts in improving the overall efficiency of coupled hydrogen production.We have developed an efficient lanthanum-dopedα-Ni(OH)_(2) bifunctional catalyst with a 1D-2D-3D hierarchical nanostructure.It shows superior activity and stability in the anodic oxygen evolution reaction(OER)and urea oxidation reaction(UOR).Enrichment of the edge sites and conducting La doping inα-Ni(OH)_(2) phase enable formation and stabilization of abundant local Ni^(3+)ions.This guarantees ultralow onset potentials in electro-oxidation reactions.The 1D-2D-3D hierarchical nanostructure significantly boosts the in situ generation of high-valence active species,which results in efficient and stable OER and UOR performances,and the synergistic merit of doping-induced facile reaction kinetics.Because of the structural benefits of a large surface area,charge-transfer promotion,good structural stability,and bifunctionality,a 1%La-dopedα-Ni(OH)_(2) hierarchical nanostructure gives superior OER and UOR performances with low overpotentials,large catalytic current densities,and excellent operational stability.It is therefore a promising catalyst for use in simultaneous alkaline wastewater treatment and hydrogen production.