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
Fe-N-C catalysts are promising substitutes for precious-metal platinum in acidic oxygen reduction reactions(ORR),yet their moderate intrinsic activity and susceptibility to reactive oxygen species(ROS)-induced degrada...Fe-N-C catalysts are promising substitutes for precious-metal platinum in acidic oxygen reduction reactions(ORR),yet their moderate intrinsic activity and susceptibility to reactive oxygen species(ROS)-induced degradation hinder practical implementation.Herein,we fabricate a Ru-Fe dual-site catalyst(RuFe-N-C)through a two-step pyrolysis strategy.Structural characterization reveals atomic-scale proximity between Ru single atoms and Fe-N_(4) moieties,exhibiting a projected distance of~1.7Å.This configuration induces Fe–N bond elongation accompanied by 2.5%lattice distortion.The optimized RuFe-N-C catalyst exhibits high ORR performance,with a half-wave potential(E_(1/2))of 0.840 V and peak power density(P_(max))of 938 mW cm^(-2) under 150 kPa absolute H_(2)-O_(2).These metrics signify substantial enhancements relative to conventional Fe-N-C benchmarks(+21 mV in E_(1/2) and+42%in P_(max)).Moreover,the catalyst maintains outstanding stability,showing merely 17 mV E_(1/2) decay after 10000 accelerated durability test(ADT)cycles.Experimental analyses reveal a bifunctional mechanism:(1)Adjacent Ru sites substantially enhance the intrinsic ORR activity of Fe-N_(4) moieties,delivering a notable turnover frequency(TOF=17.86 e site^(-1) s^(-1) at 0.85 V vs.RHE)that exceeds state-of-the-art Fe-N-C benchmarks by 1-2 orders of magnitude(<1 e site^(-1) s^(-1));(2)Ru centers function as electron relays that facilitate ROS scavenging,thus suppressing degradation.This work establishes a paradigm for engineering bimetallic single-atom catalysts through synergistic electronic modulation to concurrently enhance activity and stability.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
Objective: To investigate the effects of different delivery modes on perinatal pelvic floor muscle strength, PG, ACTH and CRP of high-risk pregnant women. Methods: 380 high-risk pregnant women who gave birth in our ho...Objective: To investigate the effects of different delivery modes on perinatal pelvic floor muscle strength, PG, ACTH and CRP of high-risk pregnant women. Methods: 380 high-risk pregnant women who gave birth in our hospital from March 2021 to February 2022 were selected as subjects, including 100 vaginal natural delivery, 156 forceps assisted delivery and 124 cesarean section. Pelvic floor pressure, PG, ACTH, CRP, IL-6, TNF-α and IL-4, IL-10 levels were evaluated and compared. The perinatal occurrence of pelvic floor functional disease (PFD) in high-risk pregnant women in each group was analyzed and evaluated. Results: There were statistical differences in the amount of postpartum blood loss (P 0.0001, F = 99.01), postpartum blood loss 24 h (P = 0.0004, F = 19.54) and hospital stay (P 0.0001, F = 70.81) among the three groups of high-risk women in natural vaginal delivery, forceps delivery and cesarean section. In addition, there were 72, 134 and 70 cases of abnormal pelvic floor fatigue in natural vaginal delivery, forceps assisted delivery and cesarean section (P 0.0001, χ<sup>2</sup> = 30.16). There were 36, 79 and 21 cases of muscle injury, respectively (P 0.0001, χ<sup>2</sup> = 34.16). There were 49, 98 and 43 cases of dysmuscular contraction, respectively (P 0.0001, χ<sup>2</sup> = 21.94). There were 65, 120 and 41 cases with vaginal dynamic pressure 80 cm H<sub>2</sub>O (P 0.0001, χ<sup>2</sup> = 56.86), respectively. The.展开更多
AIM:To investigate the association between functionaloutcomes and postoperative patient satisfaction 5y aftersmall incision lenticule extraction(SMILE)and femtosecondlaser-assisted in situ keratomileusis(FS-LASIK).MET...AIM:To investigate the association between functionaloutcomes and postoperative patient satisfaction 5y aftersmall incision lenticule extraction(SMILE)and femtosecondlaser-assisted in situ keratomileusis(FS-LASIK).METHODS:This is a cross-sectional study.Thepatients underwent basic ophthalmic examinations,axiallength measurement,wide-field fundus photography,andaccommodation function testing.Behavioral habits datawere collected using a self-administered questionnaire,andvisual symptoms were assessed with the Quality of Vision(QoV)questionnaire.Postoperative satisfaction was alsorecorded.RESULTS:Totally 410 subjects[820 eyes,160males(39.02%)and 250 females(60.98%)]who hadundergone SMILE or FS-LASIK 5y ago were enrolled.Themean(standard deviation,SD)age of all patients was29.83y(6.69).The mean(SD)preoperative manifest SEwas-5.80(2.04)diopters(D;range:-0.88 to-13.75).Patient satisfaction at 5y after undergoing SMILE or FSLASIKwas 91.70%.Patients were categorized into twogroups:dissatisfied group and satisfied group.Significantdifferences were observed between the two groups in termsof age(P=0.012),sex(P=0.021),preoperative degreeof myopia(P=0.049),postoperative visual symptoms(frequency,P=0.043;severity,P<0.001;bothersome,P=0.018),difficulty driving at night(P=0.001),andaccommodative amplitude(AMP,P=0.020).Multivariateanalysis confirmed that female sex(P=0.024),severityof visual symptoms(P=0.009),and difficulty driving atnight(P=0.006)were significantly associated with lowersatisfaction.The dissatisfied group showed higher rates ofstarbursts,double or multiple images,and high myopia,but lower age.The frequency,severity,and bothersome ofdistortion exhibited decreased with increasing age.CONCLUSION:Patient satisfaction 5y after SMILEand FS-LASIK is high and stable.Difficulty driving at night,sex,and severity of visual symptoms are important factorsinfluencing patient satisfaction.Special attention should bepaid to younger highly myopic female patients,particularlythose with starbursts and double or multiple images.It is crucial to monitor postoperative visual outcomesand provide patients with comprehensive preoperativecounseling to enhance long-term satisfaction.展开更多
Corrosion-resistant high nitrogen high entropy alloys(HEAs)were manufactured by pressurized metal-lurgy.This work revealed the inhibitory effect of nitrogen on pitting corrosion of HEAs caused by sul-fate reducing bac...Corrosion-resistant high nitrogen high entropy alloys(HEAs)were manufactured by pressurized metal-lurgy.This work revealed the inhibitory effect of nitrogen on pitting corrosion of HEAs caused by sul-fate reducing bacterium Desulfovibrio vulgaris.Results indicated that HEA-0 N was susceptible to pitting corrosion and sulfidation under attack of D.vulgaris,whereas the addition of nitrogen significantly de-creased the pitting sensitivity.Pitting potentials of HEA-0.52 N and HEA-1.23 N increased by 133%and 171%,respectively compared to HEA-0 N in the presence of SRB.X-ray photoelectron spectroscopy results unveiled that nitrogen enriched in passive film and strengthened it by increasing fraction of Cr_(2)O_(3)and Fe^(3+)_(ox).Surface of the nitrogen-alloyed HEAs exhibited less defective passive films as revealed by Mott-Schottky results.Nitrogen doping provides a novel insight into the design of microbial corrosion resistant HEA.展开更多
The effect of nitrogen on microstructural evolution and tensile properties of transformation-induced plasticity(TRIP)Fe_(50)Mn_(30)Co_(10)Cr_(10)HEAs was investigated.Nitrogen was fully introduced in solid solution by...The effect of nitrogen on microstructural evolution and tensile properties of transformation-induced plasticity(TRIP)Fe_(50)Mn_(30)Co_(10)Cr_(10)HEAs was investigated.Nitrogen was fully introduced in solid solution by pressure-induced melting technique.Nitrogen addition turned the TRIP alloy to a twinning-induced plasticity(TWIP)alloy,and simultaneously improved the strength and elongation.For the nitrogen-doped HEA,the high yield strength is mainly resulted from the friction stress via interstitial strengthening effect,and the high ductility is originated from retained high strain-hardening capability via the successive onset of dislocation accumulation and deformation twinning.The strain-hardening behavior and microstructural evolution at specified strains were revealed.展开更多
The application of ionic liquids in perovskite has attracted wide-spread attention for its astounding performance improvement of perovskite solar cells(PSCs).However,the detailed mechanisms behind the improvement rema...The application of ionic liquids in perovskite has attracted wide-spread attention for its astounding performance improvement of perovskite solar cells(PSCs).However,the detailed mechanisms behind the improvement remain mysterious.Herein,a series of imidazolium-based ionic liquids(IILs)with different cations and anions is systematically investigated to elucidate the passivation mechanism of IILs on inorganic perovskites.It is found that IILs display the following advantages:(1)They form ionic bonds with Cs^(+)and Pb^(2+)cations on the surface and at the grain boundaries of perovskite films,which could effectively heal/reduce the Cs^(+)/I−vacancies and Pb-related defects;(2)They serve as a bridge between the perovskite and the hole-transport-layer for effective charge extraction and transfer;and(3)They increase the hydrophobicity of the perovskite surface to further improve the stability of the CsPbI_(2)Br PSCs.The combination of the above effects results in suppressed non-radiative recombination loss in CsPbI_(2)Br PSCs and an impressive power conversion efficiency of 17.02%.Additionally,the CsPbI_(2)Br PSCs with IILs surface modification exhibited improved ambient and light illumination stability.Our results provide guidance for an indepth understanding of the passivation mechanism of IILs in inorganic perovskites.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
The Pt/FeSnO（OH）_5 catalyst has been prepared by depositing Pt nanoparticles on the synthesized FeSnO（OH）_5 nanoboxes and demonstrates excellent performance towards methanol oxidation reaction（MOR） in direct met...The Pt/FeSnO（OH）_5 catalyst has been prepared by depositing Pt nanoparticles on the synthesized FeSnO（OH）_5 nanoboxes and demonstrates excellent performance towards methanol oxidation reaction（MOR） in direct methanol fuel cells（DMFCs）.The Pt/FeSnO（OH）_5 catalyst exhibits a higher mass activity（1182.35 mA/mgPt） compared with Pt/C（594.57 mA/mgPt） catalysts.The X-ray powder diffraction,field emission scanning electron microscope,field emission transmission electron microscopy,X-ray photoelectron spectroscopy and electrochemical experiments have been employed to explore the relationships between the crystal structure and electrochemical properties.The increased activity and resistance of CO poisoning for Pt/FeSnO（OH）_5 catalyst can be attributed to the strong interaction between the transition metal in the hydroxide and Pt and the bifunctional effect.The higher relative concentration of Pt^0 in Pt/FeSnO（OH）_5 also contributes to the MOR activity.Moreover,the charge transfer resistance of Pt/FeSnO（OH）_5 is lower than that of Pt/C.Therefore,Pt/FeSnO（OH）_5 has great application prospect as a high-performance electrocatalyst in DMFCs.展开更多
Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811) cathode material has been widely concerned due to its high voltage,high specific capacity and excellent rate performance,which is considered as one of the most promi...Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811) cathode material has been widely concerned due to its high voltage,high specific capacity and excellent rate performance,which is considered as one of the most promising cathode materials for the next generation of high-energy-density solid-state lithium batteries.However,serious electro-chemo-mechanical degradation of Nickel-rich cathode during cycling,especially at a high voltage(over 4.5 V),constrains their large-scale application.Here,using the multiphysical simulation,highly-conductive polymer matrix with spontaneous stress-buffering effect was uncovered theoretically for reinforcing the electrochemical performance of composited NCM81 1 cathode through the visualization of uniform concentration distribution of Li-ion coupled with improved stress field inside NCM811 cathode.Thereupon,polyacrylonitrile(PAN) and soft polyvinylidene fluoride(PVDF) were selected as the polymer matrix to fabricate the composited NCM811 cathode(PVDFPAN@NCM811) for improving the electrochemical performance of the solid-state NMC811|Li full cells,which can maintain high capacity over 146.2 mA h g^(-1)after 200 cycles at a high voltage of 4.5 V.Suggestively,designing a multifunctional polymer matrix with high ionic conductivity and mechanical property can buffer the stress and maintain the integrity of the structure,which can be regarded as the door-opening avenue to realize the high electrochemical performance of Ni-rich cathode for solidstate batteries.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
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.
文摘Fe-N-C catalysts are promising substitutes for precious-metal platinum in acidic oxygen reduction reactions(ORR),yet their moderate intrinsic activity and susceptibility to reactive oxygen species(ROS)-induced degradation hinder practical implementation.Herein,we fabricate a Ru-Fe dual-site catalyst(RuFe-N-C)through a two-step pyrolysis strategy.Structural characterization reveals atomic-scale proximity between Ru single atoms and Fe-N_(4) moieties,exhibiting a projected distance of~1.7Å.This configuration induces Fe–N bond elongation accompanied by 2.5%lattice distortion.The optimized RuFe-N-C catalyst exhibits high ORR performance,with a half-wave potential(E_(1/2))of 0.840 V and peak power density(P_(max))of 938 mW cm^(-2) under 150 kPa absolute H_(2)-O_(2).These metrics signify substantial enhancements relative to conventional Fe-N-C benchmarks(+21 mV in E_(1/2) and+42%in P_(max)).Moreover,the catalyst maintains outstanding stability,showing merely 17 mV E_(1/2) decay after 10000 accelerated durability test(ADT)cycles.Experimental analyses reveal a bifunctional mechanism:(1)Adjacent Ru sites substantially enhance the intrinsic ORR activity of Fe-N_(4) moieties,delivering a notable turnover frequency(TOF=17.86 e site^(-1) s^(-1) at 0.85 V vs.RHE)that exceeds state-of-the-art Fe-N-C benchmarks by 1-2 orders of magnitude(<1 e site^(-1) s^(-1));(2)Ru centers function as electron relays that facilitate ROS scavenging,thus suppressing degradation.This work establishes a paradigm for engineering bimetallic single-atom catalysts through synergistic electronic modulation to concurrently enhance activity and stability.
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.
文摘Objective: To investigate the effects of different delivery modes on perinatal pelvic floor muscle strength, PG, ACTH and CRP of high-risk pregnant women. Methods: 380 high-risk pregnant women who gave birth in our hospital from March 2021 to February 2022 were selected as subjects, including 100 vaginal natural delivery, 156 forceps assisted delivery and 124 cesarean section. Pelvic floor pressure, PG, ACTH, CRP, IL-6, TNF-α and IL-4, IL-10 levels were evaluated and compared. The perinatal occurrence of pelvic floor functional disease (PFD) in high-risk pregnant women in each group was analyzed and evaluated. Results: There were statistical differences in the amount of postpartum blood loss (P 0.0001, F = 99.01), postpartum blood loss 24 h (P = 0.0004, F = 19.54) and hospital stay (P 0.0001, F = 70.81) among the three groups of high-risk women in natural vaginal delivery, forceps delivery and cesarean section. In addition, there were 72, 134 and 70 cases of abnormal pelvic floor fatigue in natural vaginal delivery, forceps assisted delivery and cesarean section (P 0.0001, χ<sup>2</sup> = 30.16). There were 36, 79 and 21 cases of muscle injury, respectively (P 0.0001, χ<sup>2</sup> = 34.16). There were 49, 98 and 43 cases of dysmuscular contraction, respectively (P 0.0001, χ<sup>2</sup> = 21.94). There were 65, 120 and 41 cases with vaginal dynamic pressure 80 cm H<sub>2</sub>O (P 0.0001, χ<sup>2</sup> = 56.86), respectively. The.
基金Supported by Research and Transformation Application of Capital Clinical Diagnosis and Treatment Technology by Beijing Municipal Commission of Science and Technology(No.Z201100005520043).
文摘AIM:To investigate the association between functionaloutcomes and postoperative patient satisfaction 5y aftersmall incision lenticule extraction(SMILE)and femtosecondlaser-assisted in situ keratomileusis(FS-LASIK).METHODS:This is a cross-sectional study.Thepatients underwent basic ophthalmic examinations,axiallength measurement,wide-field fundus photography,andaccommodation function testing.Behavioral habits datawere collected using a self-administered questionnaire,andvisual symptoms were assessed with the Quality of Vision(QoV)questionnaire.Postoperative satisfaction was alsorecorded.RESULTS:Totally 410 subjects[820 eyes,160males(39.02%)and 250 females(60.98%)]who hadundergone SMILE or FS-LASIK 5y ago were enrolled.Themean(standard deviation,SD)age of all patients was29.83y(6.69).The mean(SD)preoperative manifest SEwas-5.80(2.04)diopters(D;range:-0.88 to-13.75).Patient satisfaction at 5y after undergoing SMILE or FSLASIKwas 91.70%.Patients were categorized into twogroups:dissatisfied group and satisfied group.Significantdifferences were observed between the two groups in termsof age(P=0.012),sex(P=0.021),preoperative degreeof myopia(P=0.049),postoperative visual symptoms(frequency,P=0.043;severity,P<0.001;bothersome,P=0.018),difficulty driving at night(P=0.001),andaccommodative amplitude(AMP,P=0.020).Multivariateanalysis confirmed that female sex(P=0.024),severityof visual symptoms(P=0.009),and difficulty driving atnight(P=0.006)were significantly associated with lowersatisfaction.The dissatisfied group showed higher rates ofstarbursts,double or multiple images,and high myopia,but lower age.The frequency,severity,and bothersome ofdistortion exhibited decreased with increasing age.CONCLUSION:Patient satisfaction 5y after SMILEand FS-LASIK is high and stable.Difficulty driving at night,sex,and severity of visual symptoms are important factorsinfluencing patient satisfaction.Special attention should bepaid to younger highly myopic female patients,particularlythose with starbursts and double or multiple images.It is crucial to monitor postoperative visual outcomesand provide patients with comprehensive preoperativecounseling to enhance long-term satisfaction.
基金This work was financially supported by the National Natural Science Foundation of China(No.U2006219)the National Key Re-search and Development Program of China(No.2020YFA0907300)+1 种基金the Fundamental Research Funds for the Central Universities of the Ministry of Education of China(Nos.N2102009 and N2002019)Liaoning Revitalization Talents Program(No.XLYC1907158).
文摘Corrosion-resistant high nitrogen high entropy alloys(HEAs)were manufactured by pressurized metal-lurgy.This work revealed the inhibitory effect of nitrogen on pitting corrosion of HEAs caused by sul-fate reducing bacterium Desulfovibrio vulgaris.Results indicated that HEA-0 N was susceptible to pitting corrosion and sulfidation under attack of D.vulgaris,whereas the addition of nitrogen significantly de-creased the pitting sensitivity.Pitting potentials of HEA-0.52 N and HEA-1.23 N increased by 133%and 171%,respectively compared to HEA-0 N in the presence of SRB.X-ray photoelectron spectroscopy results unveiled that nitrogen enriched in passive film and strengthened it by increasing fraction of Cr_(2)O_(3)and Fe^(3+)_(ox).Surface of the nitrogen-alloyed HEAs exhibited less defective passive films as revealed by Mott-Schottky results.Nitrogen doping provides a novel insight into the design of microbial corrosion resistant HEA.
基金financially supported by the National Natural Science Foundation of China(Nos.U1960203,51774074,51434004 and U1435205)the Fundamental Research Funds for the Central Universities(No.N180204015)+1 种基金the Shanxi Municipal Major Science&Technology Project(No.20181101014)the Fundamental Research Funds for the Central Universities(No.N172512033)。
文摘The effect of nitrogen on microstructural evolution and tensile properties of transformation-induced plasticity(TRIP)Fe_(50)Mn_(30)Co_(10)Cr_(10)HEAs was investigated.Nitrogen was fully introduced in solid solution by pressure-induced melting technique.Nitrogen addition turned the TRIP alloy to a twinning-induced plasticity(TWIP)alloy,and simultaneously improved the strength and elongation.For the nitrogen-doped HEA,the high yield strength is mainly resulted from the friction stress via interstitial strengthening effect,and the high ductility is originated from retained high strain-hardening capability via the successive onset of dislocation accumulation and deformation twinning.The strain-hardening behavior and microstructural evolution at specified strains were revealed.
基金support from the National Natural Science Foundation of China(62074095)the National Key Research and Development Program of China(2016YFA0202403)+3 种基金the Fundamental Research Funds for the Central Universities(GK202002001)the 111 Project(Grant No.B21005)the DNL Cooperation Fund CAS(DNL180311)the support of H2 cluster in Xi’an Jiaotong University.
文摘The application of ionic liquids in perovskite has attracted wide-spread attention for its astounding performance improvement of perovskite solar cells(PSCs).However,the detailed mechanisms behind the improvement remain mysterious.Herein,a series of imidazolium-based ionic liquids(IILs)with different cations and anions is systematically investigated to elucidate the passivation mechanism of IILs on inorganic perovskites.It is found that IILs display the following advantages:(1)They form ionic bonds with Cs^(+)and Pb^(2+)cations on the surface and at the grain boundaries of perovskite films,which could effectively heal/reduce the Cs^(+)/I−vacancies and Pb-related defects;(2)They serve as a bridge between the perovskite and the hole-transport-layer for effective charge extraction and transfer;and(3)They increase the hydrophobicity of the perovskite surface to further improve the stability of the CsPbI_(2)Br PSCs.The combination of the above effects results in suppressed non-radiative recombination loss in CsPbI_(2)Br PSCs and an impressive power conversion efficiency of 17.02%.Additionally,the CsPbI_(2)Br PSCs with IILs surface modification exhibited improved ambient and light illumination stability.Our results provide guidance for an indepth understanding of the passivation mechanism of IILs in inorganic perovskites.
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supported by the State Key Laboratory of Photocatalysis on Energy and Environment Open Project(SKLPEE-KF201606)Fuzhou University Testing Fund of precious apparatus(2017T007)
文摘The Pt/FeSnO（OH）_5 catalyst has been prepared by depositing Pt nanoparticles on the synthesized FeSnO（OH）_5 nanoboxes and demonstrates excellent performance towards methanol oxidation reaction（MOR） in direct methanol fuel cells（DMFCs）.The Pt/FeSnO（OH）_5 catalyst exhibits a higher mass activity（1182.35 mA/mgPt） compared with Pt/C（594.57 mA/mgPt） catalysts.The X-ray powder diffraction,field emission scanning electron microscope,field emission transmission electron microscopy,X-ray photoelectron spectroscopy and electrochemical experiments have been employed to explore the relationships between the crystal structure and electrochemical properties.The increased activity and resistance of CO poisoning for Pt/FeSnO（OH）_5 catalyst can be attributed to the strong interaction between the transition metal in the hydroxide and Pt and the bifunctional effect.The higher relative concentration of Pt^0 in Pt/FeSnO（OH）_5 also contributes to the MOR activity.Moreover,the charge transfer resistance of Pt/FeSnO（OH）_5 is lower than that of Pt/C.Therefore,Pt/FeSnO（OH）_5 has great application prospect as a high-performance electrocatalyst in DMFCs.
基金financially supported by the Natural Science Foundation of Hunan Province(2020JJ5653)the National Natural Science Foundation of China(21875282,22102212)+1 种基金the Ministry of Science and Higher Education of the Russian Federation(07515-2022-1150)the National University of Defense Technology Scientific Research Project(ZK20-44)。
文摘Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811) cathode material has been widely concerned due to its high voltage,high specific capacity and excellent rate performance,which is considered as one of the most promising cathode materials for the next generation of high-energy-density solid-state lithium batteries.However,serious electro-chemo-mechanical degradation of Nickel-rich cathode during cycling,especially at a high voltage(over 4.5 V),constrains their large-scale application.Here,using the multiphysical simulation,highly-conductive polymer matrix with spontaneous stress-buffering effect was uncovered theoretically for reinforcing the electrochemical performance of composited NCM81 1 cathode through the visualization of uniform concentration distribution of Li-ion coupled with improved stress field inside NCM811 cathode.Thereupon,polyacrylonitrile(PAN) and soft polyvinylidene fluoride(PVDF) were selected as the polymer matrix to fabricate the composited NCM811 cathode(PVDFPAN@NCM811) for improving the electrochemical performance of the solid-state NMC811|Li full cells,which can maintain high capacity over 146.2 mA h g^(-1)after 200 cycles at a high voltage of 4.5 V.Suggestively,designing a multifunctional polymer matrix with high ionic conductivity and mechanical property can buffer the stress and maintain the integrity of the structure,which can be regarded as the door-opening avenue to realize the high electrochemical performance of Ni-rich cathode for solidstate batteries.
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。
