The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportio...The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst design.Herein,a Ni2+-loaded porous poly(ionic liquids)(PIL)precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing temperature.The catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO_(2)into CO.Operando Ni K-edge X-ray absorption near-edge structure(XANES)spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and NPs.The charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active sites.In the electroreduction of CO_(2),the coexistence of Ni SAs and NPs strengthened the CO_(2)activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO_(2)→*COOH step,and therefore promoted the catalysis efficiency.展开更多
Regulating the location of the metal promoters plays a vital role in catalyst structure and its catalytic behavior during CO_(2)hydrogenation to higher alcohols.Herein,we selected the metal promoters with a precipitat...Regulating the location of the metal promoters plays a vital role in catalyst structure and its catalytic behavior during CO_(2)hydrogenation to higher alcohols.Herein,we selected the metal promoters with a precipitation pH similar to that of Cu^(2+)or Fe^(3+)to prepare a series of CuFe-based catalysts.Characterization results show that doping Al or Cr promoter,located with the Fe phase,suppressed the excessive carburization of the Fe phase and maintained an optimal proportion between Fe_(3)O_(4) and amorphous iron carbide(FeC_(x)),thus exhibiting superior catalytic activity and stability.In contrast,doping Zn or In promoter,located with the Cu phase,underwent a deeper carburization and formed more crys-talline FeC_(x),showing an inferior performance.The CuFeCr catalyst achieved the highest space-time yield of 330 mg g_(cat)^(-1)h^(-1)for higher alcohols among these catalysts.This study provides a novel strategy for opti-mizing the structure of the active phases for CO_(2)hydrogenation.展开更多
Molybdenum carbide has shown great potential in various hydrogenation reactions,and serves as a primary active species for synthesis of ethanol from dimethyl oxalate hydrogenation process which is a crucial step in th...Molybdenum carbide has shown great potential in various hydrogenation reactions,and serves as a primary active species for synthesis of ethanol from dimethyl oxalate hydrogenation process which is a crucial step in the efficient utilization of coal resources.In this study,a molybdenum carbide catalyst with a three-dimensional mesh-like hollow structure and lattice defects was carefully designed.The MoO_(3)precursor with abundant oxygen vacancies and defects was prepared by flame spray pyrolysis,and a structural modifier,Cu,was introduced by sputtering.The Cu deposited by sputtering affected the carburization and phase evolution processes.A three-dimensional mesh-like hollow structure composed of defective molybdenum carbide is formed,with theβ-Mo_(2)C exhibiting lattice distortions and defects.This defectiveβ-Mo_(2)C exhibits high reactivity,and facilitates the C=O hydrogenation process,showing a high reactivity of 83.1%yield in the hydrogenation of dimethyl oxalate.This work provides a new approach to the design and application of molybdenum carbide catalysts.展开更多
The exchange of inorganic nutrients at the coastal sediment-water interface(SWI)plays a crucial role in regulating the nutrient budget in overlying water.The related studies mainly focus on the mid-to high-latitude re...The exchange of inorganic nutrients at the coastal sediment-water interface(SWI)plays a crucial role in regulating the nutrient budget in overlying water.The related studies mainly focus on the mid-to high-latitude regions,leaving a significant gap in the quantitative assessment of nutrient exchange and environmental controls at the SWI in lowlatitude coastal regions.We quantitatively assess the exchange of inorganic nutrients at the SWI in three tropical bays(Dongzhai Harbor,Xiaohai Lagoon,Qinglan Harbor).Sediments act as a source of ammonium,phosphate,and silicate,but for nitrate,sediments can be both a source and sink,although with substantial spatial and temporal variations in their fluxes.Labile organic matter is a critical regulator for the fluxes of inorganic nutrients at the SWI.The sedimentary nutrients input with high N/P molar ratio will alter the nutrient stoichiometry to mitigate the nitrogen limitation in coastal waters.However,the internal sediment release in these tropical bays plays a relative weak role in contributing to the nutrient addition in comparison with the other external nutrient sources including riverine input,submarine groundwater discharge,and atmospheric deposition.According to the global compilation on SWI nutrient fluxes,we propose that water column primary production and external inputs to interpret the variation in exchange and fluxes of nutrients at the SWI in different ecosystems.Such a conceptual understanding of these chain biogeochemical processes involving external nutrient input,primary production,particulate organic matter settling,and the accumulation and release of inorganic nutrients in sediments will be helpful for the scientific-based pollution prevent and control in coastal waters.展开更多
Prescribed burning is commonly used to maintain forest ecosystem functions and reduce the risk of future wildfires.Although many studies have investigated the response of microbial community to wildfires in forest eco...Prescribed burning is commonly used to maintain forest ecosystem functions and reduce the risk of future wildfires.Although many studies have investigated the response of microbial community to wildfires in forest ecosystems,the effects of prescribed burnings on soil microbial community structure are less studied.It is also unclear that how post-fire soil physiochemical properties changes affected soil microbial communities.Here,we studied the impacts of prescribed burning on soil microbiome in three typical temperate forests of northern China by collecting soil physicochemical and high-throughput sequencing for 16S rRNA and 18S rRNA was applied to analyze the diversity and community composition of soil microbes(bacteria and fungi).Compared with pre-fire condition,prescribed burning significantly decreased Chaol index and altered soil bacterial communities(P<0.05),whereas it had no significant effect on fungal diversity and community structure of the(P>0.05).Planctomycetes and Actinobacteria made the greatest contributions to the bacterial community dissimilarity between the pre-fire and post-fire conditions.The main variables influencing the post-fire soil microbial community structure are soil pH,available phosphorus,total nitrogen,and the ratio of soil total carbon to soil total nitrogen,which could account for 73.5% of the variation in the microbial community structure in these stands.Our findings demonstrated a great discrepancy in the responses of bacteria and fungi to prescribed burning.Prescribed burning altered the soil microbial structure by modifying the physicochemical properties.Our results pointed that it is essential to evaluate the impact of prescribed burnings on forest ecosystem functions.These findings provide an important baseline for assessing post-fire microbial recovery in the region and offer critical guidance for restoration efforts.展开更多
With lanthanum(La) in agriculture, medicine, and the chemical industry, La shows accumulation in the body, especially in the bone, because of its similar structure to calcium. Moreover, La has a direct role in bone fo...With lanthanum(La) in agriculture, medicine, and the chemical industry, La shows accumulation in the body, especially in the bone, because of its similar structure to calcium. Moreover, La has a direct role in bone formation regulating osteoblasts and osteoclasts. Nevertheless, bone formation is complex under the regulation of osteogenesis, osteoclastogenesis, and angiogenesis in the bone microenvironment. It is difficult to comprehensively understand the regulation of bone homeostasis from a single kind of cell.Herein, some bone microenvironment-related cells and mouse calvaria culture models were used to study the regulatory effect of La-based compound-lanthanum nitrate(La(NO_(3))_(3)) on bone formation.La(NO_(3))_(3) has good biological safety, and the osteogenic differentiation is significantly increased under La(NO_(3))_(3) treatment for bone marrow mesenchymal stem cells(BMMSC). In contrast, the differentiation,maturation, and bone erosion ability of osteoclasts are significantly decreased. Meanwhile, the angiogenesis ability of human umbilical vein endothelial cells(HUVEC) is significantly promoted when treated with La(NO_(3))_(3). Furthermore, bone metabolism and angiogenesis are improved under La(NO_(3))_(3) treatment in the calvaria ex vivo culture model and BMMSC-HUVEC co-culture system. These results suggest that La has the beneficial effect of promoting bone metabolism and improving bone formation in the bone microenvironment.展开更多
能源电力系统低碳转型是中国实现碳达峰碳中和目标的基础和关键,生物质发电是保障能源安全前提下电力系统低碳转型的关键技术之一。在深入进行国内外生物质发电情况及政策调研基础上,系统梳理了中国生物质发电的发展和常规大气污染物的...能源电力系统低碳转型是中国实现碳达峰碳中和目标的基础和关键,生物质发电是保障能源安全前提下电力系统低碳转型的关键技术之一。在深入进行国内外生物质发电情况及政策调研基础上,系统梳理了中国生物质发电的发展和常规大气污染物的排放绩效等情况,研究了“双碳”目标下生物质发电面临的机遇与挑战,提出了发展路径建议。研究表明:(1)2010—2022年中国生物质发电装机容量快速增长,2022年底中国生物质发电装机容量已达4132万kW,整体技术水平先进,但规模仍然偏小,农林生物质发电在火电装机容量中占比仅为1.2%。(2)生物质电厂大气污染物排放控制技术取得重要进展,污染物排放得到有效控制。(3)生物质用于火力发电时具有转动惯量特性,可为光伏等新能源发电大力发展造成的电力系统转动惯量不足起到互补作用;且生物质是“碳中性”能源,综合利用生物质发电可为农民增加收入、可以替代高碳化石能源发电、采用生物质碳捕获和封存技术(bioenergy with carbon capture and storage,BECCS)工艺时可成为负碳技术,从全社会收益看,具有较好的正外部经济性,应当加大力度发展。(4)存在支持生物质发电的经济政策不到位,企业生产经营困难、大气污染物排放控制要求不适合、缺乏证明其低碳属性的权威方法学和补偿机制、在碳市场或国家核证自愿减排量市场中难以发挥作用等问题。(5)建议中国生物质发电的发展路径分为四个阶段:2025年前完善政策;2026—2030年积极有序发展生物质发电;2040年前持续扩大生物质发电规模,积累BECCS技术;2060年前生物质发电成为电力系统稳定运行的重要支撑和降碳发电技术,部分生物质发电机组可采用BECCS负碳技术,通过国际间碳排放交易产生效益。展开更多
Nano-computed tomography(Nano-CT)is an emerging,high-resolution imaging technique.However,due to their low-light properties,tabletop Nano-CT has to be scanned under long exposure conditions,which the scanning process ...Nano-computed tomography(Nano-CT)is an emerging,high-resolution imaging technique.However,due to their low-light properties,tabletop Nano-CT has to be scanned under long exposure conditions,which the scanning process is time-consuming.For 3D reconstruction data,this paper proposed a lightweight 3D noise reduction method for desktop-level Nano-CT called AAD-ResNet(Axial Attention DeNoise ResNet).The network is framed by theU-net structure.The encoder and decoder are incorporated with the proposed 3D axial attention mechanism and residual dense block.Each layer of the residual dense block can directly access the features of the previous layer,which reduces the redundancy of parameters and improves the efficiency of network training.The 3D axial attention mechanism enhances the correlation between 3D information in the training process and captures the long-distance dependence.It can improve the noise reduction effect and avoid the loss of image structure details.Experimental results show that the network can effectively improve the image quality of a 0.1-s exposure scan to a level close to a 3-s exposure,significantly shortening the sample scanning time.展开更多
基金National Natural Science Foundation of China(grants 22072065,22178162,and 22222806)Distinguished Youth Foundation of Jiangsu Province(grant BK20220053)Six talent peaks project in Jiangsu Province(grant JNHB-035)。
文摘The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst design.Herein,a Ni2+-loaded porous poly(ionic liquids)(PIL)precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing temperature.The catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO_(2)into CO.Operando Ni K-edge X-ray absorption near-edge structure(XANES)spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and NPs.The charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active sites.In the electroreduction of CO_(2),the coexistence of Ni SAs and NPs strengthened the CO_(2)activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO_(2)→*COOH step,and therefore promoted the catalysis efficiency.
基金financially supported by the National Key R&D Program of China (2023YFB4104501)the National Natural Science Foundation of China (22372165)+2 种基金the Liaoning Binhai Laboratory (LBLA-2024-01)the Grant. YLU-DNL Fund (2023001)DICP (Grant: DICP I202457)
文摘Regulating the location of the metal promoters plays a vital role in catalyst structure and its catalytic behavior during CO_(2)hydrogenation to higher alcohols.Herein,we selected the metal promoters with a precipitation pH similar to that of Cu^(2+)or Fe^(3+)to prepare a series of CuFe-based catalysts.Characterization results show that doping Al or Cr promoter,located with the Fe phase,suppressed the excessive carburization of the Fe phase and maintained an optimal proportion between Fe_(3)O_(4) and amorphous iron carbide(FeC_(x)),thus exhibiting superior catalytic activity and stability.In contrast,doping Zn or In promoter,located with the Cu phase,underwent a deeper carburization and formed more crys-talline FeC_(x),showing an inferior performance.The CuFeCr catalyst achieved the highest space-time yield of 330 mg g_(cat)^(-1)h^(-1)for higher alcohols among these catalysts.This study provides a novel strategy for opti-mizing the structure of the active phases for CO_(2)hydrogenation.
文摘Molybdenum carbide has shown great potential in various hydrogenation reactions,and serves as a primary active species for synthesis of ethanol from dimethyl oxalate hydrogenation process which is a crucial step in the efficient utilization of coal resources.In this study,a molybdenum carbide catalyst with a three-dimensional mesh-like hollow structure and lattice defects was carefully designed.The MoO_(3)precursor with abundant oxygen vacancies and defects was prepared by flame spray pyrolysis,and a structural modifier,Cu,was introduced by sputtering.The Cu deposited by sputtering affected the carburization and phase evolution processes.A three-dimensional mesh-like hollow structure composed of defective molybdenum carbide is formed,with theβ-Mo_(2)C exhibiting lattice distortions and defects.This defectiveβ-Mo_(2)C exhibits high reactivity,and facilitates the C=O hydrogenation process,showing a high reactivity of 83.1%yield in the hydrogenation of dimethyl oxalate.This work provides a new approach to the design and application of molybdenum carbide catalysts.
基金The Major Science and Technology Plan of Hainan Province under contract No.ZDKJ2021008the Hainan Provincial Natural Science Foundation of China under contract No.623RC456+1 种基金the Hainan Province Science and Technology Special Fund under contract Nos ZDYF2021SHFZ064 and ZDYF2022SHFZ056the Collaborative Innovation Center of Marine Science and Technology in Hainan University under contract No.XTCX2022HYC19.
文摘The exchange of inorganic nutrients at the coastal sediment-water interface(SWI)plays a crucial role in regulating the nutrient budget in overlying water.The related studies mainly focus on the mid-to high-latitude regions,leaving a significant gap in the quantitative assessment of nutrient exchange and environmental controls at the SWI in lowlatitude coastal regions.We quantitatively assess the exchange of inorganic nutrients at the SWI in three tropical bays(Dongzhai Harbor,Xiaohai Lagoon,Qinglan Harbor).Sediments act as a source of ammonium,phosphate,and silicate,but for nitrate,sediments can be both a source and sink,although with substantial spatial and temporal variations in their fluxes.Labile organic matter is a critical regulator for the fluxes of inorganic nutrients at the SWI.The sedimentary nutrients input with high N/P molar ratio will alter the nutrient stoichiometry to mitigate the nitrogen limitation in coastal waters.However,the internal sediment release in these tropical bays plays a relative weak role in contributing to the nutrient addition in comparison with the other external nutrient sources including riverine input,submarine groundwater discharge,and atmospheric deposition.According to the global compilation on SWI nutrient fluxes,we propose that water column primary production and external inputs to interpret the variation in exchange and fluxes of nutrients at the SWI in different ecosystems.Such a conceptual understanding of these chain biogeochemical processes involving external nutrient input,primary production,particulate organic matter settling,and the accumulation and release of inorganic nutrients in sediments will be helpful for the scientific-based pollution prevent and control in coastal waters.
基金financially supported by the National Natural Science Foundation(No.32471868,No.32001324)Youth Lift Project of China Association for Science and Technology(No.YESS20210370)+1 种基金Fundamental Research Funds for the Central Universities(2572023CT01)We thank the Grassland Bureau and the National Innovation Alliance of Wildland Fire Prevention and Control Technology of China for supporting this research.
文摘Prescribed burning is commonly used to maintain forest ecosystem functions and reduce the risk of future wildfires.Although many studies have investigated the response of microbial community to wildfires in forest ecosystems,the effects of prescribed burnings on soil microbial community structure are less studied.It is also unclear that how post-fire soil physiochemical properties changes affected soil microbial communities.Here,we studied the impacts of prescribed burning on soil microbiome in three typical temperate forests of northern China by collecting soil physicochemical and high-throughput sequencing for 16S rRNA and 18S rRNA was applied to analyze the diversity and community composition of soil microbes(bacteria and fungi).Compared with pre-fire condition,prescribed burning significantly decreased Chaol index and altered soil bacterial communities(P<0.05),whereas it had no significant effect on fungal diversity and community structure of the(P>0.05).Planctomycetes and Actinobacteria made the greatest contributions to the bacterial community dissimilarity between the pre-fire and post-fire conditions.The main variables influencing the post-fire soil microbial community structure are soil pH,available phosphorus,total nitrogen,and the ratio of soil total carbon to soil total nitrogen,which could account for 73.5% of the variation in the microbial community structure in these stands.Our findings demonstrated a great discrepancy in the responses of bacteria and fungi to prescribed burning.Prescribed burning altered the soil microbial structure by modifying the physicochemical properties.Our results pointed that it is essential to evaluate the impact of prescribed burnings on forest ecosystem functions.These findings provide an important baseline for assessing post-fire microbial recovery in the region and offer critical guidance for restoration efforts.
基金Project supported by the National Natural Science Foundation of China(21807023)the Natural Science Foundation of Hebei Province(B2019201449,H2019201466)+2 种基金the Hebei Province“Three Three Three Talents Program”(A202003001)the Government Guided Local Science and Technology Fundations of Hebei Province(216Z2403G)the Priority Strategy Project of the Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education(ts2020003)。
文摘With lanthanum(La) in agriculture, medicine, and the chemical industry, La shows accumulation in the body, especially in the bone, because of its similar structure to calcium. Moreover, La has a direct role in bone formation regulating osteoblasts and osteoclasts. Nevertheless, bone formation is complex under the regulation of osteogenesis, osteoclastogenesis, and angiogenesis in the bone microenvironment. It is difficult to comprehensively understand the regulation of bone homeostasis from a single kind of cell.Herein, some bone microenvironment-related cells and mouse calvaria culture models were used to study the regulatory effect of La-based compound-lanthanum nitrate(La(NO_(3))_(3)) on bone formation.La(NO_(3))_(3) has good biological safety, and the osteogenic differentiation is significantly increased under La(NO_(3))_(3) treatment for bone marrow mesenchymal stem cells(BMMSC). In contrast, the differentiation,maturation, and bone erosion ability of osteoclasts are significantly decreased. Meanwhile, the angiogenesis ability of human umbilical vein endothelial cells(HUVEC) is significantly promoted when treated with La(NO_(3))_(3). Furthermore, bone metabolism and angiogenesis are improved under La(NO_(3))_(3) treatment in the calvaria ex vivo culture model and BMMSC-HUVEC co-culture system. These results suggest that La has the beneficial effect of promoting bone metabolism and improving bone formation in the bone microenvironment.
基金Development Path of Biomass Energy in China Based on Dual Carbon Goals(Stage 1):Technical Policy Research on Biomass Application inPower System under Dual Carbon Goals(G-2203-33075)。
文摘能源电力系统低碳转型是中国实现碳达峰碳中和目标的基础和关键,生物质发电是保障能源安全前提下电力系统低碳转型的关键技术之一。在深入进行国内外生物质发电情况及政策调研基础上,系统梳理了中国生物质发电的发展和常规大气污染物的排放绩效等情况,研究了“双碳”目标下生物质发电面临的机遇与挑战,提出了发展路径建议。研究表明:(1)2010—2022年中国生物质发电装机容量快速增长,2022年底中国生物质发电装机容量已达4132万kW,整体技术水平先进,但规模仍然偏小,农林生物质发电在火电装机容量中占比仅为1.2%。(2)生物质电厂大气污染物排放控制技术取得重要进展,污染物排放得到有效控制。(3)生物质用于火力发电时具有转动惯量特性,可为光伏等新能源发电大力发展造成的电力系统转动惯量不足起到互补作用;且生物质是“碳中性”能源,综合利用生物质发电可为农民增加收入、可以替代高碳化石能源发电、采用生物质碳捕获和封存技术(bioenergy with carbon capture and storage,BECCS)工艺时可成为负碳技术,从全社会收益看,具有较好的正外部经济性,应当加大力度发展。(4)存在支持生物质发电的经济政策不到位,企业生产经营困难、大气污染物排放控制要求不适合、缺乏证明其低碳属性的权威方法学和补偿机制、在碳市场或国家核证自愿减排量市场中难以发挥作用等问题。(5)建议中国生物质发电的发展路径分为四个阶段:2025年前完善政策;2026—2030年积极有序发展生物质发电;2040年前持续扩大生物质发电规模,积累BECCS技术;2060年前生物质发电成为电力系统稳定运行的重要支撑和降碳发电技术,部分生物质发电机组可采用BECCS负碳技术,通过国际间碳排放交易产生效益。
基金supported by the National Natural Science Foundation of China(62201618).
文摘Nano-computed tomography(Nano-CT)is an emerging,high-resolution imaging technique.However,due to their low-light properties,tabletop Nano-CT has to be scanned under long exposure conditions,which the scanning process is time-consuming.For 3D reconstruction data,this paper proposed a lightweight 3D noise reduction method for desktop-level Nano-CT called AAD-ResNet(Axial Attention DeNoise ResNet).The network is framed by theU-net structure.The encoder and decoder are incorporated with the proposed 3D axial attention mechanism and residual dense block.Each layer of the residual dense block can directly access the features of the previous layer,which reduces the redundancy of parameters and improves the efficiency of network training.The 3D axial attention mechanism enhances the correlation between 3D information in the training process and captures the long-distance dependence.It can improve the noise reduction effect and avoid the loss of image structure details.Experimental results show that the network can effectively improve the image quality of a 0.1-s exposure scan to a level close to a 3-s exposure,significantly shortening the sample scanning time.
