Developing efficient and stable non-precious metal catalysts is essential for replacing platinum-based catalysts in polymer electrolyte membrane fuel cells(PEMFCs).The transition metal and nitrogen co-doped carbon ele...Developing efficient and stable non-precious metal catalysts is essential for replacing platinum-based catalysts in polymer electrolyte membrane fuel cells(PEMFCs).The transition metal and nitrogen co-doped carbon electrocatalyst(M-N-C)is considered an effective alternative to precious metal catalysts.However,its relatively poor performance in acidic environments has always been a problem plaguing its practical application in PEMFCs.This study presents a sequential deposition methodology for constructing a composite catalytic system of Fe-N-C and ionic liquid(IL),which exhibits improved performance at both half-cell and membrane electrode assembly scales.The presence of IL significantly inhibits H_(2)O_(2)production,preferentially promoting the 4e–O_(2)reduction reaction,resulting in improved electrocatalytic activity and stability.Additionally,the enhanced PEMFC performance of IL containing electrodes is a direct result of the improved ionic and reactant accessibility of the pore confined Fe-N-C catalysts where the IL minimizes local resistive transport losses.This study establishes a strategic foundation for the practical utilization of non-precious metal catalysts in PEMFCs and other energy converting technologies.展开更多
Copper oxide(CuO)has attracted considerable interest as a promising anode material for Li-ion batteries due to its high theoretical capacity.However,its practical application is hindered by large volume changes,low in...Copper oxide(CuO)has attracted considerable interest as a promising anode material for Li-ion batteries due to its high theoretical capacity.However,its practical application is hindered by large volume changes,low inferior conductivity,and poor cycling stability.In this study,we develop a binder-free and additive-free in-situ integrated strategy to directly integrate CuO onto current collectors,thereby achieving 100%active material utilization and significantly improved electrochemical performance.The resulting anode delivers a remarkable capacity retention of 660.0 mAh·g^(-1) after 1300 cycles,accompanied by the stabilization of an octahedral CuO morphology upon charge–discharge cycles.Crucially,the in-situ formed cubic Cu_(2)O serves as a structural intermediary between cubic Cu and monoclinic CuO,enhancing mechanical stability and facilitating Li^(+)transport.Density functional theory(DFT)calculations further reveal that Cu^(+)-induced oxygen vacancies effectively promote electron conduction,provide additional sites for Li storage,leading to enhanced lithiation capacity.展开更多
Magnesium hydride,as an important light-metal hydrogen storage material for on-board hydrogen storage,aerospace,and energy fields,has long been limited in its large-scale applications by slow hydrogen storage speed an...Magnesium hydride,as an important light-metal hydrogen storage material for on-board hydrogen storage,aerospace,and energy fields,has long been limited in its large-scale applications by slow hydrogen storage speed and high dehydrogenation temperature.In this work,ultra-stable bimetallic MXene Mo_(2)V_(2)C_(3)was successfully synthesized and used to accelerate the hydrogen storage speed and reduce the dehydrogenation/hydrogenation temperature of MgH_(2).The MgH_(2)+10 wt%Mo_(2)V_(2)C_(3)sample starts dehydrogenation at 180℃and reaches the maximum dehydrogenation rate at 259℃.It also exhibits outstanding room-temperature(RT)rapid hydrogenation performance and cycling stability,retaining up to 100%capacity after 50 cycles at 300℃.Another interesting phenomenon is that the hydrogen storage speed of the sample is even faster without capacity decrease as the dehydrogenation/re-hydrogena tion cycle proceeds.First-principles calculations show that the Mg atoms are stabilized at the top sites of Mo atoms,and the Mg-H bonds that are adsorbed on Mo_(2)V_(2)C_(3)are more susceptible to breakage.The key to the accelerated rate of Mg/MgH_(2)hydrogenation/dehydrogenation is the enhancement of the interaction between Mg/MgH_(2)and Mo_(2)V_(2)C_(3)MXene with the increasing number of cycles,whereas the existence of the V renders the structure of MXene more stable.Our study refines the mechanistic understanding of bimetallic MXene catalyst for MgH_(2)hydrogen storage and expands reference on the type and preparation of bimetallic MXene.展开更多
Objective This study examines utilizes the advantages of machine learning algorithms to discern key determinants in prognosticate postoperative circulatory complications(PCCs)for older patients.Methods This secondary ...Objective This study examines utilizes the advantages of machine learning algorithms to discern key determinants in prognosticate postoperative circulatory complications(PCCs)for older patients.Methods This secondary analysis of data from a randomized controlled trial involved 1,720 elderly participants in five tertiary hospitals in Beijing,China.Participants aged 60–90 years undergoing major non-cardiac surgery under general anesthesia.The primary outcome metric of the study was the occurrence of PCCs,according to the European Society of Cardiology and the European Society of Anaesthesiology diagnostic criteria.The analysis metrics contained 67 candidate variables,including baseline characteristics,laboratory tests,and scale assessments.Results Our feature selection process identified key variables that significantly impact patient outcomes,including the duration of ICU stay,surgery,and anesthesia;APACHE-Ⅱscore;intraoperative average heart rate and blood loss;cumulative opioid use during surgery;patient age;VAS-Move-Median score on the 1st to 3rd day;Charlson comorbidity score;volumes of intraoperative plasma,crystalloid,and colloid fluids;cumulative red blood cell transfusion during surgery;and endotracheal intubation duration.Notably,our Random Forest model demonstrated exceptional performance with an accuracy of 0.9872.Conclusion We have developed and validated an algorithm for predicting PCCs in elderly patients by identifying key risk factors.展开更多
Two novel seco-polycyclic polyprenylated acylphloroglucinols(PPAPs),hyperbenzones A(1)and B(2),were isolated from the roots of Hypericum beanii,together with one known biosynthetic congener 3.Compound 1 incorporates a...Two novel seco-polycyclic polyprenylated acylphloroglucinols(PPAPs),hyperbenzones A(1)and B(2),were isolated from the roots of Hypericum beanii,together with one known biosynthetic congener 3.Compound 1 incorporates a 6/5/5 ring system with an unprecedented spiro[bicyclo[3.3.0]octane-3,1'-cyclohexane]-2,2'-dione motif.The structures of 1 and 2 were determined by a combination of high resolution electrospray ionization mass spectroscopy(HRESIMS),nuclear magnetic resonance(NMR)spectroscopic analyses,gage-independent atomic orbital(GIAO)NMR chemical shift calculation with DP4+analyses,electronic circular dichroism(ECD)calculation,and X-ray diffraction analysis.A 1,2-seco retroClaisen rearrangement from a bicyclo[3.3.1]nonane PPAP precursor and following chemodivergent radical cascade cyclizations are proposed as the key steps in the biosynthetic pathway to yield compounds 1 and2.Biological investigations indicated that compounds 1 and 3 could decrease intracellular lipid accumulation in a palmitic acid-induced nonalcoholic steatohepatitis(NASH)cell model.展开更多
Pyrus pyrifolia Nakai‘Whangkeumbae'is a sand pear fruit with excellent nutritional quality and taste.However,the industrial development of pear fruit is significantly limited by its short shelf life.Salicylic aci...Pyrus pyrifolia Nakai‘Whangkeumbae'is a sand pear fruit with excellent nutritional quality and taste.However,the industrial development of pear fruit is significantly limited by its short shelf life.Salicylic acid(SA),a well-known phytohormone,can delay fruit senescence and improve shelf life.However,the mechanism by which SA regulates CONSTANS-LIKE genes(COLs)during fruit senescence and the role of COL genes in mediating fruit senescence in sand pear are poorly understood.In this study,22 COL genes were identified in sand pear,including four COLs(Pp COL8,Pp COL9a,Pp COL9b,and Pp COL14)identified via transcriptome analysis and 18 COLs through genome-wide analysis.These COL genes were divided into three subgroups according to the structural domains of the COL protein.Pp COL8,with two B-box motifs and one CCT domain,belonged to the first subgroup.In contrast,the other three Pp COLs,Pp COL9a,Pp COL9b,and Pp COL14,with similar conserved protein domains and gene structures,were assigned to the third subgroup.The four COLs showed different expression patterns in pear tissues and were preferentially expressed at the early stage of fruit development.Moreover,the expression of Pp COL8 was inhibited by exogenous SA treatment,while SA up-regulated the expression of Pp COL9a and Pp COL9b.Interestingly,Pp COL8 interacts with Pp MADS,a MADS-box protein preferentially expressed in fruit,and SA up-regulated its expression.While the production of ethylene and the content of malondialdehyde(MDA)were increased in Pp COL8-overexpression sand pear fruit,the antioxidant enzyme(POD and SOD)activity and the expression of Pp POD1 and Pp SOD1 in the sand pear fruits were down-regulated,which showed that Pp COL8 promoted sand pear fruit senescence.In contrast,the corresponding changes were the opposite in Pp MADS-overexpression sand pear fruits,suggesting that Pp MADS delayed sand pear fruit senescence.The co-transformation of Pp COL8 and Pp MADS also delayed sand pear fruit senescence.The results of this study revealed that Pp COL8 can play a key role in pear fruit senescence by interacting with Pp MADS through the SA signaling pathway.展开更多
The practical application of Lithium-Sulfur batteries largely depends on highly efficient utilization and conversion of sulfur under the realistic condition of high-sulfur content and low electrolyte/sulfur ratio.Rati...The practical application of Lithium-Sulfur batteries largely depends on highly efficient utilization and conversion of sulfur under the realistic condition of high-sulfur content and low electrolyte/sulfur ratio.Rational design of heterostructure electrocatalysts with abundant active sites and strong interfacial electronic interactions is a promising but still challenging strategy for preventing shuttling of polysulfides in lithium-sulfur batteries.Herein,ultrathin nonlayered NiO/Ni_(3)S_(2)heterostructure nanosheets are developed through topochemical transformation of layered Ni(OH)_(2)templates to improve the utilization of sulfur and facilitate stable cycling of batteries.As a multifunction catalyst,NiO/Ni_(3)S_(2)not only enhances the adsorption of polysulfides and shorten the transport path of Li ions and electrons but also promotes the Li_(2)S formation and transformation,which are verified by both in-situ Raman spectroscopy and electrochemical investigations.Thus,the cell with NiO/Ni_(3)S_(2)as electrocatalyst delivers an area capacity of 4.8 mAh cm^(-2)under the high sulfur loading(6 mg cm^(-2))and low electrolyte/sulfur ratio(4.3 pL mg^(-1)).The strategy can be extended to 2D Ni foil,demonstrating its prospects in the construction of electrodes with high gravimetric/volumetric energy densities.The designed electrocatalyst of ultrathin nonlayered heterostructure will shed light on achieving high energy density lithium-sulfur batteries.展开更多
This paper discusses the implicit function of refusal expressions that has been used by Chinese native speakers when responding to people’s offerings.By analyzing three conversations regarding how Chinese people have...This paper discusses the implicit function of refusal expressions that has been used by Chinese native speakers when responding to people’s offerings.By analyzing three conversations regarding how Chinese people have accepted people’s offerings during different time periods(1960’s,1980’s,and 2000’s),the author argues that the verbal refusal in reacting to people’s offerings(especially gifts)does not literally mean“No,I don’t want it.”Instead,it is a way to show humility,politeness,and respect to the gift giver,and it functions as an implicit form of acceptance.By referring to three excerpts chosen from The Book of Rites(Liji禮記),the author demonstrates the Chinese cultural values and cultural themes,focusing on what Chinese people say and do to show respect and politeness when dealing with gifts or other friendliness related offerings.The paper finds two pedagogical implications:1)it is the instructor’s responsibility to highlight the verbal and non-verbal behaviors that both native speakers and language learners do not ordinarily notice in language class,and 2)the repetitive contextualized performances in different levels of learning are necessary and play crucial roles in teaching and learning.展开更多
Degenerative cervical myelopathy is a common cause of spinal cord injury,with longer symptom duration and higher myelopathy severity indicating a worse prognosis.While numerous studies have investigated serological bi...Degenerative cervical myelopathy is a common cause of spinal cord injury,with longer symptom duration and higher myelopathy severity indicating a worse prognosis.While numerous studies have investigated serological biomarkers for acute spinal cord injury,few studies have explored such biomarkers for diagnosing degenerative cervical myelopathy.This study involved 30 patients with degenerative cervical myelopathy(51.3±7.3 years old,12 women and 18 men),seven healthy controls(25.7±1.7 years old,one woman and six men),and nine patients with cervical spondylotic radiculopathy(51.9±8.6 years old,three women and six men).Analysis of blood samples from the three groups showed clear differences in transcriptomic characteristics.Enrichment analysis identified 128 differentially expressed genes that were enriched in patients with neurological disabilities.Using least absolute shrinkage and selection operator analysis,we constructed a five-gene model(TBCD,TPM2,PNKD,EIF4G2,and AP5Z1)to diagnose degenerative cervical myelopathy with an accuracy of 93.5%.One-gene models(TCAP and SDHA)identified mild and severe degenerative cervical myelopathy with accuracies of 83.3%and 76.7%,respectively.Signatures of two immune cell types(memory B cells and memory-activated CD4^(+)T cells)predicted levels of lesions in degenerative cervical myelopathy with 80%accuracy.Our results suggest that peripheral blood RNA biomarkers could be used to predict lesion severity in degenerative cervical myelopathy.展开更多
This study introduces an innovative composite cathode catalyst layer(CCL)design for proton exchange membrane fuel cells(PEMFCs),combining Pt-supported by Vulcan carbon(Pt/V)and Ketjenblack carbon(Pt/KB)to overcome mas...This study introduces an innovative composite cathode catalyst layer(CCL)design for proton exchange membrane fuel cells(PEMFCs),combining Pt-supported by Vulcan carbon(Pt/V)and Ketjenblack carbon(Pt/KB)to overcome mass transport limitations and ionomer-induced catalyst poisoning.The composite architecture strategically positions Pt/V layer with lower ionomer-to-carbon ratio(I/C=0.6)near the proton exchange membrane to maximize surface Pt accessibility and oxygen transport efficiency,whereas Pt/KB layer(I/C=0.9)adjacent to the gas diffusion layer leverages its porous structure to shield Pt from sulfonate group poisoning and enhance proton conduction under low-humidity conditions.This synergistic carbon support engineering achieves a balance between reactant accessibility and catalyst utilization,as demonstrated by improved power density,reduced transport resistance,and higher Pt utilization under dry conditions.These findings establish a new paradigm for low-Pt CCL design through rational carbon support hybridization and ionomer gradient engineering,offering a scalable solution for high-performance PEMFCs in energy-critical applications.展开更多
High entropy alloys(HEAs)have garnered significant attention due to their distinctive properties,while their precise regulation remains at infancy stage.Herein,we report PtSnBiPdIn HEA nanoparticles with tensilestrain...High entropy alloys(HEAs)have garnered significant attention due to their distinctive properties,while their precise regulation remains at infancy stage.Herein,we report PtSnBiPdIn HEA nanoparticles with tensilestrain and nanoporous structures as high-performance electrocatalysts for oxidation of ethylene glycol to CO_(2).The mass activity(MA)of the PtSnBiPdIn/C catalyst for alkaline ethylene glycol oxidation reaction(EGOR)are 29.76 A·mgPt+Pd−1,which not only substantially surpasses those of commercial Pt/C and Pd/C catalysts but also ranks among the best reported EGOR catalysts.Moreover,this catalyst also greatly enhances in electrocatalytic performance for both methanol oxidation reaction(MOR)and ethanol oxidation reaction(EOR),showcasing its versatility across a wide range of alcohol oxidation reactions.In-situ Fourier transform infrared(FTIR)spectroscopy confirms the preferential selection of the non-CO reaction pathway.Density functional theory(DFT)calculation reveals that the PtSnBiPdIn HEA nanoparticles exhibit enhanced electron transfer,superior catalytic activity,and remarkable CO poisoning resistance.展开更多
Straw strip mulching(SM)is a new mulching technology.From 2012 to 2018,SM’s effects on soil moisture and temperature and production performances were compared with other mulching practices,using three treatments:full...Straw strip mulching(SM)is a new mulching technology.From 2012 to 2018,SM’s effects on soil moisture and temperature and production performances were compared with other mulching practices,using three treatments:full-cover plastic mulch(PM),no mulch with wheat sown in rows as the control(CK),and SM with 50%to 59%of the field area mulched.Compared with CK,on average over six growing seasons,SM and PM increased grain yield by 27.0%and 21.7%,straw yield by 21.6%and 22.6%,kernels ha;by 26.6%and 19.0%,net income by 29.8%and-25.0%,soil temperature at 5 cm by-1.5°C and 0.2°C from overwintering to maturity,and soil water storage at 0–200 cm by 25 and 22 mm,respectively.The increase in soil moisture in SM and PM was greater in the early period(overwintering to jointing)than in the later period(booting to maturity)and at 0 to 120 cm than at 120–200 cm in the early period.Although the mean evapotranspiration of whole growth period across six seasons was similar among treatments,SM and PM increased water consumption during the key formation period of yield components after overwintering by 16 and 32 mm,respectively,while reducing it before overwintering.Compared with CK,SM and PM had the effects of warming during overwintering and cooling after jointing.By increasing water consumption after overwintering and ratio of transpiration to evapotranspiration and providing favorable soil temperature for multiple growth stages and more sufficient soil moisture,SM and PM promoted vegetative growth and increased kernels ha^(-1),the main mechanisms by which SM and PM increased grain yield relative to CK.Relative to PM,SM is a more economically beneficial and environment-friendly technology for dryland wheat production.展开更多
The porous p-type BiSbTebulks containing irregularly and randomly oriented pores were obtained by artificially controlling the relative density of sintered samples during resistance pressing sintering process. It is d...The porous p-type BiSbTebulks containing irregularly and randomly oriented pores were obtained by artificially controlling the relative density of sintered samples during resistance pressing sintering process. It is demonstrated that the thermoelectric performances are significantly affected by the porous structure, especially for the electrical and thermal conductivity due to the enhanced carrier scattering and phonon scattering. The increasing porosity resulted in the obvious decrease in electrical and thermal conductivity, and little change in Seebeck coefficients. It is encouraging that the reduction of thermal conductivity can compensate for the deterioration of electrical performance, leading to the enhancement in thermoelectric figure of merit(ZT). The maximum ZT value of 1.0 was obtained for the sample with a relative density of 90% at 333 K. Unfortunately, the increase in porosity also brought in obvious degradations in Vickers hardness from 51.71 to 27.74 HV. It is worth mentioning that although the Vickers hardness of the sample with a relative density of 90% decreased to 40.12 HV, it was still about twice as high as that of the zone melting sample(21.25 HV). To summarize, introducing pores structure into bulks properly not only enhances the ZT value of BiTebased alloys, but also reduces the use of raw materials and saves production cost.展开更多
Microscopic vision has been widely applied in precision assembly.To achieve sufficiently high resolution in measurements for precision assembly when the sizes of the parts involved exceed the field of view of the visi...Microscopic vision has been widely applied in precision assembly.To achieve sufficiently high resolution in measurements for precision assembly when the sizes of the parts involved exceed the field of view of the vision system,an image mosaic technique must be used.In this paper,a method for constructing an image mosaic with non-overlapping areas with enhanced efficiency is proposed.First,an image mosaic model for the part is created using a geometric model of the measurement system installed on a X-Y-Z precision stages with high repeatability,and a path for image acquisition is established.Second,images are captured along the same path for a specified calibration plate,and an entire image is formed based on the given model.The measurement results obtained from the specified calibration plate are utilized to identify mosaic errors and apply compensation for the part requiring measurement.Experimental results show that the maximum error is less than 4μm for a camera with pixel equivalent 2.46μm,thereby demonstrating the accuracy of the proposed method.This image mosaic technique with non-overlapping regions can simplify image acquisition and reduce the workload involved in constructing an image mosaic.展开更多
The active deforming southeastern margin of the Tibetan Plateau has developed series of fault basins filled with fluvial-lacustrine sediment deposited by drainage systems during every stage of its uplifting,the record...The active deforming southeastern margin of the Tibetan Plateau has developed series of fault basins filled with fluvial-lacustrine sediment deposited by drainage systems during every stage of its uplifting,the records of Cenozoic sedimentary sequence and detrital provenance in these basins are often obscure,making the interpretation of the drainage reorganization quite difficult.This research discovered the earliest Late Cenozoic fluvial conglomerate in the Yuanmou Basin,one of the fault basins in SE Xizang,and named the conglomerate as'the Yuanmou Gravel Layer(YMG)'.Clast petrography,morphology and paleocurrent directions of the YMG indicate that the conglomerate is the remain of a large paleo river traversing through the Yuanmou Basin from north to south.Detrital zircon U-Pb ages can imply the YMG has similar provenance areas with Anning,Dadu and Yalong rivers at age peaks of 175-275,600-1000,and 2100-2700 Ma,but the lack of the age peak of 30-100 Ma from Qiangtang Block implies that the paleo-river was not yet connected with the Jinsha River during the YMG's accumulation.The fluvial-lacustrine strata with gravel beds containing paleosimian fossils comparable to the YMG were deposited~7-11 Ma,further suggesting that the pre-formed south-flowing river was active during the Late Miocene.展开更多
Hydrogen energy is one of the ideal energy alternatives and the upstream of the hydrogen industry chain is hydrogen production,which can be achieved via the reaction of inorganic materials with water,known as hydrolys...Hydrogen energy is one of the ideal energy alternatives and the upstream of the hydrogen industry chain is hydrogen production,which can be achieved via the reaction of inorganic materials with water,known as hydrolysis.Among inorganic materials,the high hydrogen capacity for hydrolysis of MgH_(2)(15.2 wt%)makes it a promising material for hydrogen production via hydrolysis.However,the dense Mg(OH)_(2) passivation layer will block the reaction between MgH_(2) and the solution,resulting in low hydrogen yield and sluggish hydrolysis kinetics.In this work,the hydrogenyield and hydrogen generation rate of MgH_(2) are considerably enhanced by adding Ti-Zr-Fe-Mn-Cr-V high-entropy alloys(HEAs) for the first time.In particular.the MgH_(2)-3 wt% TiZrFe_(1.5)MnCrV_(0.5)(labelled as MgH_(2)-3 wt% Fe_(1.5)) composite releases 1526.70 mL/g H_(2) within 5 min at 40℃,and the final hydrolysis conversion rate reaches 95.62% within 10 min.The mean hydrogen generation rate of the MgH_(2)-3 wt% Fe_(1.5) composite is 289.16 mL/g/min,which is 2.38 times faster than that of pure MgH_(2).Meanwhile,the activation energy of the MgH_(2)-3 wt% Fe_(1.5) composite is calculated to be 12.53 kJ/mol. The density functional theory(DFT) calculation reveals that the addition of HEAs weakens the Mg-H bonds and accelerates the electron transfer between MgH_(2) and HEAs,Combined with the cocktail effect of HEAs as well as the formation of more interfaces and micro protocells,the hydrolysis performance of MgH_(2) is considerably improved.This work provides an appealing prospect for real-time hydrogen supply and offers a new effective strategy for improving the hydrolysis performance of MgH_(2).展开更多
WUSCHEL-related homeobox(WOX)transcription factors play a crucial role in lateral organ development in several plant species;however,their precise functions in soybean(Glycine max[L.]Merr.)were unclear.Here,we identif...WUSCHEL-related homeobox(WOX)transcription factors play a crucial role in lateral organ development in several plant species;however,their precise functions in soybean(Glycine max[L.]Merr.)were unclear.Here,we identified two independent multi-leaflet soybean mutants,mlw48-8 and mlw48-161,from a CRISPR/Cas9-engineered mutant library in the Williams 82 background.Both mutants exhibited irregular leaf margins,and the upper leaves were narrow and almost lanceolate at maturity.Molecular analysis revealed that these are allelic mutants with independent mutations in the WUSCHEL-related homeobox1(GmWOX1A)gene.A transcriptome analysis demonstrated that GmWOX1A modulates the expression of auxin-and leaf development–related genes.Yeast two-hybrid and split-luciferase complementation imaging assays revealed that GmWOX1A interacts with the YABBY family protein GmYAB5,providing further evidence of its potential involvement in leaf development.Notably,the mlw48-161 mutant showed an increased seed number per plant.Consequently,our study not only provides valuable insights into the role of GmWOX1A in soybean leaf development but also offers a potential strategy for high-yield breeding.展开更多
Pollution flashover is one of themajor insulation accidents that can occur inmodern power systems.If the local arc is not sufficiently elongated by the creepage distance,the flashover performance of the insulator will...Pollution flashover is one of themajor insulation accidents that can occur inmodern power systems.If the local arc is not sufficiently elongated by the creepage distance,the flashover performance of the insulator will decrease.The insulator structure and equivalent salt deposition density(ESDD)are the main factors affecting the arc path and length.To investigate the forms of arc paths under different insulator structures and their influence on flashover characteristics,a platformfor recording arc paths is established.This study presents amethod to identify the pattern and distribution of insulator arc paths based on the effect of initial arc on electric field distribution.The results show that there are two main types of local arc paths between umbrellas—the cling-surface arc and the air-jump arc.Moreover,the air-jump arc includes two types—the bridging arc and the gap arc.With the increase in umbrella spacing and ESDD,the probability of arc propagation along the surface increases.The use of the creepage distance can be improved by changing the creepage coefficient to increase the distance between umbrellas.This method has over 90%accuracy.This study is of great significance for improving insulator structure and reducing pollution flashover accidents.展开更多
The lamellar hydrates of CAC were designed with the introduction of nano CaCO_(3)or Mg-Al hydrotalcite(M-A-H),and the effects on the green strength,pore structures,and high-temperature fracture behavior of alumina-spi...The lamellar hydrates of CAC were designed with the introduction of nano CaCO_(3)or Mg-Al hydrotalcite(M-A-H),and the effects on the green strength,pore structures,and high-temperature fracture behavior of alumina-spinel castables were investigated.The results show that nano CaCO_(3)or M-A-H stimulates rapidly the hydration of CAC and the formation of lamellar C_(4)AcH_(11)or coexistence of C_(2)AH_(8)and C_(4)AcH_(11)at 25℃.The formation of lamellar hydrates can contribute to a more complicated pore structure,especially in the range of 400-2000 nm.Meanwhile,the incorporation of well-distributed CaO or MgO sources from nano CaCO_(3)or M-A-H also regulates the distribution of CA_(6)and spinel(pre-formed and in-situ).Consequently,the optimized microstructure and complicated pore structure can induce the deflection and bridging of cracks,thus facilitating the consumption of fracture energy and enhancing the resistance to thermal stress damage.展开更多
基金国家自然科学基金(22202124,22208376)山西省科技创新团队专项资金(202304051001023)+3 种基金山西省重点研发计划(202302060301009)山西省国家留学基金委(2023-008,2023-009)山东省自然科学基金(ZR2023LFG005)青岛新能源山东实验室开放项目(QNESL OP 202303).
文摘Developing efficient and stable non-precious metal catalysts is essential for replacing platinum-based catalysts in polymer electrolyte membrane fuel cells(PEMFCs).The transition metal and nitrogen co-doped carbon electrocatalyst(M-N-C)is considered an effective alternative to precious metal catalysts.However,its relatively poor performance in acidic environments has always been a problem plaguing its practical application in PEMFCs.This study presents a sequential deposition methodology for constructing a composite catalytic system of Fe-N-C and ionic liquid(IL),which exhibits improved performance at both half-cell and membrane electrode assembly scales.The presence of IL significantly inhibits H_(2)O_(2)production,preferentially promoting the 4e–O_(2)reduction reaction,resulting in improved electrocatalytic activity and stability.Additionally,the enhanced PEMFC performance of IL containing electrodes is a direct result of the improved ionic and reactant accessibility of the pore confined Fe-N-C catalysts where the IL minimizes local resistive transport losses.This study establishes a strategic foundation for the practical utilization of non-precious metal catalysts in PEMFCs and other energy converting technologies.
基金supported by the National Natural Science Foundation of China(Nos.52401277,52201250,52271212,and 52471225)the Fundamental Research Funds for the Central Universities(No.2024MS084)the Double-First Class project for the North China Electric Power University(NCEPU).
文摘Copper oxide(CuO)has attracted considerable interest as a promising anode material for Li-ion batteries due to its high theoretical capacity.However,its practical application is hindered by large volume changes,low inferior conductivity,and poor cycling stability.In this study,we develop a binder-free and additive-free in-situ integrated strategy to directly integrate CuO onto current collectors,thereby achieving 100%active material utilization and significantly improved electrochemical performance.The resulting anode delivers a remarkable capacity retention of 660.0 mAh·g^(-1) after 1300 cycles,accompanied by the stabilization of an octahedral CuO morphology upon charge–discharge cycles.Crucially,the in-situ formed cubic Cu_(2)O serves as a structural intermediary between cubic Cu and monoclinic CuO,enhancing mechanical stability and facilitating Li^(+)transport.Density functional theory(DFT)calculations further reveal that Cu^(+)-induced oxygen vacancies effectively promote electron conduction,provide additional sites for Li storage,leading to enhanced lithiation capacity.
基金supported by the National Key Research and Development Plan(2023YFB3809101)the National Natural Science Foundation of China(Grant nos.52471225,52201250,52271212,52401277)+1 种基金the Fundamental Research Funds for the Central Universities(2024MS084)the Double-First Class project for the NCEPU。
文摘Magnesium hydride,as an important light-metal hydrogen storage material for on-board hydrogen storage,aerospace,and energy fields,has long been limited in its large-scale applications by slow hydrogen storage speed and high dehydrogenation temperature.In this work,ultra-stable bimetallic MXene Mo_(2)V_(2)C_(3)was successfully synthesized and used to accelerate the hydrogen storage speed and reduce the dehydrogenation/hydrogenation temperature of MgH_(2).The MgH_(2)+10 wt%Mo_(2)V_(2)C_(3)sample starts dehydrogenation at 180℃and reaches the maximum dehydrogenation rate at 259℃.It also exhibits outstanding room-temperature(RT)rapid hydrogenation performance and cycling stability,retaining up to 100%capacity after 50 cycles at 300℃.Another interesting phenomenon is that the hydrogen storage speed of the sample is even faster without capacity decrease as the dehydrogenation/re-hydrogena tion cycle proceeds.First-principles calculations show that the Mg atoms are stabilized at the top sites of Mo atoms,and the Mg-H bonds that are adsorbed on Mo_(2)V_(2)C_(3)are more susceptible to breakage.The key to the accelerated rate of Mg/MgH_(2)hydrogenation/dehydrogenation is the enhancement of the interaction between Mg/MgH_(2)and Mo_(2)V_(2)C_(3)MXene with the increasing number of cycles,whereas the existence of the V renders the structure of MXene more stable.Our study refines the mechanistic understanding of bimetallic MXene catalyst for MgH_(2)hydrogen storage and expands reference on the type and preparation of bimetallic MXene.
基金The trial protocol was approved by the Institutional Review Board of Peking University(approval number 00001052-11048)and the ethics committees of the five participating centerswas registered with the China Clinical Trial Registry(www.chictr.org.cn,identifier:Chi CTR-TRC-09000543)ClinicalTrials.gov(identifier:NCT01661907).
文摘Objective This study examines utilizes the advantages of machine learning algorithms to discern key determinants in prognosticate postoperative circulatory complications(PCCs)for older patients.Methods This secondary analysis of data from a randomized controlled trial involved 1,720 elderly participants in five tertiary hospitals in Beijing,China.Participants aged 60–90 years undergoing major non-cardiac surgery under general anesthesia.The primary outcome metric of the study was the occurrence of PCCs,according to the European Society of Cardiology and the European Society of Anaesthesiology diagnostic criteria.The analysis metrics contained 67 candidate variables,including baseline characteristics,laboratory tests,and scale assessments.Results Our feature selection process identified key variables that significantly impact patient outcomes,including the duration of ICU stay,surgery,and anesthesia;APACHE-Ⅱscore;intraoperative average heart rate and blood loss;cumulative opioid use during surgery;patient age;VAS-Move-Median score on the 1st to 3rd day;Charlson comorbidity score;volumes of intraoperative plasma,crystalloid,and colloid fluids;cumulative red blood cell transfusion during surgery;and endotracheal intubation duration.Notably,our Random Forest model demonstrated exceptional performance with an accuracy of 0.9872.Conclusion We have developed and validated an algorithm for predicting PCCs in elderly patients by identifying key risk factors.
基金supported by the National Natural Science Foundation of China(Nos.31900287 and 81773886)the 111 Project from Ministry of Education of China and the State Administration of Foreign Export Affairs of China(No.B18056)Special fund from the Central Committee for guiding local scientific and technological development of Shenzhen(No.2021Szvup161)。
文摘Two novel seco-polycyclic polyprenylated acylphloroglucinols(PPAPs),hyperbenzones A(1)and B(2),were isolated from the roots of Hypericum beanii,together with one known biosynthetic congener 3.Compound 1 incorporates a 6/5/5 ring system with an unprecedented spiro[bicyclo[3.3.0]octane-3,1'-cyclohexane]-2,2'-dione motif.The structures of 1 and 2 were determined by a combination of high resolution electrospray ionization mass spectroscopy(HRESIMS),nuclear magnetic resonance(NMR)spectroscopic analyses,gage-independent atomic orbital(GIAO)NMR chemical shift calculation with DP4+analyses,electronic circular dichroism(ECD)calculation,and X-ray diffraction analysis.A 1,2-seco retroClaisen rearrangement from a bicyclo[3.3.1]nonane PPAP precursor and following chemodivergent radical cascade cyclizations are proposed as the key steps in the biosynthetic pathway to yield compounds 1 and2.Biological investigations indicated that compounds 1 and 3 could decrease intracellular lipid accumulation in a palmitic acid-induced nonalcoholic steatohepatitis(NASH)cell model.
基金supported by the National Natural Science Foundation of China(32272654)the Natural Science Foundation of Hebei Province China(C2023204016)+2 种基金the Hebei Province Introduced Overseas-Scholar Fund China(C20220361)the S&T Program of Hebei China(20326330D)the Hebei Province Outstanding Youth Fund China(2016,2019)。
文摘Pyrus pyrifolia Nakai‘Whangkeumbae'is a sand pear fruit with excellent nutritional quality and taste.However,the industrial development of pear fruit is significantly limited by its short shelf life.Salicylic acid(SA),a well-known phytohormone,can delay fruit senescence and improve shelf life.However,the mechanism by which SA regulates CONSTANS-LIKE genes(COLs)during fruit senescence and the role of COL genes in mediating fruit senescence in sand pear are poorly understood.In this study,22 COL genes were identified in sand pear,including four COLs(Pp COL8,Pp COL9a,Pp COL9b,and Pp COL14)identified via transcriptome analysis and 18 COLs through genome-wide analysis.These COL genes were divided into three subgroups according to the structural domains of the COL protein.Pp COL8,with two B-box motifs and one CCT domain,belonged to the first subgroup.In contrast,the other three Pp COLs,Pp COL9a,Pp COL9b,and Pp COL14,with similar conserved protein domains and gene structures,were assigned to the third subgroup.The four COLs showed different expression patterns in pear tissues and were preferentially expressed at the early stage of fruit development.Moreover,the expression of Pp COL8 was inhibited by exogenous SA treatment,while SA up-regulated the expression of Pp COL9a and Pp COL9b.Interestingly,Pp COL8 interacts with Pp MADS,a MADS-box protein preferentially expressed in fruit,and SA up-regulated its expression.While the production of ethylene and the content of malondialdehyde(MDA)were increased in Pp COL8-overexpression sand pear fruit,the antioxidant enzyme(POD and SOD)activity and the expression of Pp POD1 and Pp SOD1 in the sand pear fruits were down-regulated,which showed that Pp COL8 promoted sand pear fruit senescence.In contrast,the corresponding changes were the opposite in Pp MADS-overexpression sand pear fruits,suggesting that Pp MADS delayed sand pear fruit senescence.The co-transformation of Pp COL8 and Pp MADS also delayed sand pear fruit senescence.The results of this study revealed that Pp COL8 can play a key role in pear fruit senescence by interacting with Pp MADS through the SA signaling pathway.
基金supported by the National Natural Science Foundation of China(Grant nos.62090013,61974043,and 91833303)the National Key R&D Program of China(Grant no.2019YFB2203403)+1 种基金the Projects of Science and Technology Commission of Shanghai Municipality(Grant nos.21JC1402100 and 19511120100)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘The practical application of Lithium-Sulfur batteries largely depends on highly efficient utilization and conversion of sulfur under the realistic condition of high-sulfur content and low electrolyte/sulfur ratio.Rational design of heterostructure electrocatalysts with abundant active sites and strong interfacial electronic interactions is a promising but still challenging strategy for preventing shuttling of polysulfides in lithium-sulfur batteries.Herein,ultrathin nonlayered NiO/Ni_(3)S_(2)heterostructure nanosheets are developed through topochemical transformation of layered Ni(OH)_(2)templates to improve the utilization of sulfur and facilitate stable cycling of batteries.As a multifunction catalyst,NiO/Ni_(3)S_(2)not only enhances the adsorption of polysulfides and shorten the transport path of Li ions and electrons but also promotes the Li_(2)S formation and transformation,which are verified by both in-situ Raman spectroscopy and electrochemical investigations.Thus,the cell with NiO/Ni_(3)S_(2)as electrocatalyst delivers an area capacity of 4.8 mAh cm^(-2)under the high sulfur loading(6 mg cm^(-2))and low electrolyte/sulfur ratio(4.3 pL mg^(-1)).The strategy can be extended to 2D Ni foil,demonstrating its prospects in the construction of electrodes with high gravimetric/volumetric energy densities.The designed electrocatalyst of ultrathin nonlayered heterostructure will shed light on achieving high energy density lithium-sulfur batteries.
文摘This paper discusses the implicit function of refusal expressions that has been used by Chinese native speakers when responding to people’s offerings.By analyzing three conversations regarding how Chinese people have accepted people’s offerings during different time periods(1960’s,1980’s,and 2000’s),the author argues that the verbal refusal in reacting to people’s offerings(especially gifts)does not literally mean“No,I don’t want it.”Instead,it is a way to show humility,politeness,and respect to the gift giver,and it functions as an implicit form of acceptance.By referring to three excerpts chosen from The Book of Rites(Liji禮記),the author demonstrates the Chinese cultural values and cultural themes,focusing on what Chinese people say and do to show respect and politeness when dealing with gifts or other friendliness related offerings.The paper finds two pedagogical implications:1)it is the instructor’s responsibility to highlight the verbal and non-verbal behaviors that both native speakers and language learners do not ordinarily notice in language class,and 2)the repetitive contextualized performances in different levels of learning are necessary and play crucial roles in teaching and learning.
基金supported by Hunan Provincial Key Research and Development Program,No.2021SK2002(to BW)the Natural Science Foundation of Hunan Province of China(General Program),No.2021JJ30938(to YL)。
文摘Degenerative cervical myelopathy is a common cause of spinal cord injury,with longer symptom duration and higher myelopathy severity indicating a worse prognosis.While numerous studies have investigated serological biomarkers for acute spinal cord injury,few studies have explored such biomarkers for diagnosing degenerative cervical myelopathy.This study involved 30 patients with degenerative cervical myelopathy(51.3±7.3 years old,12 women and 18 men),seven healthy controls(25.7±1.7 years old,one woman and six men),and nine patients with cervical spondylotic radiculopathy(51.9±8.6 years old,three women and six men).Analysis of blood samples from the three groups showed clear differences in transcriptomic characteristics.Enrichment analysis identified 128 differentially expressed genes that were enriched in patients with neurological disabilities.Using least absolute shrinkage and selection operator analysis,we constructed a five-gene model(TBCD,TPM2,PNKD,EIF4G2,and AP5Z1)to diagnose degenerative cervical myelopathy with an accuracy of 93.5%.One-gene models(TCAP and SDHA)identified mild and severe degenerative cervical myelopathy with accuracies of 83.3%and 76.7%,respectively.Signatures of two immune cell types(memory B cells and memory-activated CD4^(+)T cells)predicted levels of lesions in degenerative cervical myelopathy with 80%accuracy.Our results suggest that peripheral blood RNA biomarkers could be used to predict lesion severity in degenerative cervical myelopathy.
基金financially supported by National Natural Science Foundation of China(22202124 and UA22A20429)Shanxi Scholarship Council of China(2023-008 and 2023-009)+4 种基金Shanxi Outstanding Project Selection and Support Program for Overseas Scientific and Technological Activities(20230002)Science and Technology Innovation Teams of Shanxi Province(202304051001023)the Key Research and Development Program of Shanxi Province(No.202302060301009)Qingdao New Energy Shandong Laboratory Open Project(QNESL OP)Shandong Provincial Natural Science Foundation(Nos.ZR2024QB175 and ZR2023LFG005).
文摘This study introduces an innovative composite cathode catalyst layer(CCL)design for proton exchange membrane fuel cells(PEMFCs),combining Pt-supported by Vulcan carbon(Pt/V)and Ketjenblack carbon(Pt/KB)to overcome mass transport limitations and ionomer-induced catalyst poisoning.The composite architecture strategically positions Pt/V layer with lower ionomer-to-carbon ratio(I/C=0.6)near the proton exchange membrane to maximize surface Pt accessibility and oxygen transport efficiency,whereas Pt/KB layer(I/C=0.9)adjacent to the gas diffusion layer leverages its porous structure to shield Pt from sulfonate group poisoning and enhance proton conduction under low-humidity conditions.This synergistic carbon support engineering achieves a balance between reactant accessibility and catalyst utilization,as demonstrated by improved power density,reduced transport resistance,and higher Pt utilization under dry conditions.These findings establish a new paradigm for low-Pt CCL design through rational carbon support hybridization and ionomer gradient engineering,offering a scalable solution for high-performance PEMFCs in energy-critical applications.
基金funding from the National Natural Science Foundation of China(Nos.12475323 and U21A20317)the Natural Science Research Project of Universities in Anhui Province(Nos.2022AH050112 and 2024AH050082)+3 种基金the Project of Anhui Provincial Department of Education(No.2022AH010004)the Fund of Key Laboratory of Advanced Materials of Ministry of Education No(Advmat-2401)the Natural Science Foundation of Anhui Province(No.2108085MB55)the Fund of Development of High-Resolution X-ray Fluorescence Analyzer.
文摘High entropy alloys(HEAs)have garnered significant attention due to their distinctive properties,while their precise regulation remains at infancy stage.Herein,we report PtSnBiPdIn HEA nanoparticles with tensilestrain and nanoporous structures as high-performance electrocatalysts for oxidation of ethylene glycol to CO_(2).The mass activity(MA)of the PtSnBiPdIn/C catalyst for alkaline ethylene glycol oxidation reaction(EGOR)are 29.76 A·mgPt+Pd−1,which not only substantially surpasses those of commercial Pt/C and Pd/C catalysts but also ranks among the best reported EGOR catalysts.Moreover,this catalyst also greatly enhances in electrocatalytic performance for both methanol oxidation reaction(MOR)and ethanol oxidation reaction(EOR),showcasing its versatility across a wide range of alcohol oxidation reactions.In-situ Fourier transform infrared(FTIR)spectroscopy confirms the preferential selection of the non-CO reaction pathway.Density functional theory(DFT)calculation reveals that the PtSnBiPdIn HEA nanoparticles exhibit enhanced electron transfer,superior catalytic activity,and remarkable CO poisoning resistance.
基金State Key Laboratory of Aridland Crop Science,Gansu Agricultural University(GSCS-2019-Z05)China Agricultural Research System of the Ministry of Finance(MOF)and Ministry of Agriculture and Rural Affairs(MARA)(CARS-3-2-47)。
文摘Straw strip mulching(SM)is a new mulching technology.From 2012 to 2018,SM’s effects on soil moisture and temperature and production performances were compared with other mulching practices,using three treatments:full-cover plastic mulch(PM),no mulch with wheat sown in rows as the control(CK),and SM with 50%to 59%of the field area mulched.Compared with CK,on average over six growing seasons,SM and PM increased grain yield by 27.0%and 21.7%,straw yield by 21.6%and 22.6%,kernels ha;by 26.6%and 19.0%,net income by 29.8%and-25.0%,soil temperature at 5 cm by-1.5°C and 0.2°C from overwintering to maturity,and soil water storage at 0–200 cm by 25 and 22 mm,respectively.The increase in soil moisture in SM and PM was greater in the early period(overwintering to jointing)than in the later period(booting to maturity)and at 0 to 120 cm than at 120–200 cm in the early period.Although the mean evapotranspiration of whole growth period across six seasons was similar among treatments,SM and PM increased water consumption during the key formation period of yield components after overwintering by 16 and 32 mm,respectively,while reducing it before overwintering.Compared with CK,SM and PM had the effects of warming during overwintering and cooling after jointing.By increasing water consumption after overwintering and ratio of transpiration to evapotranspiration and providing favorable soil temperature for multiple growth stages and more sufficient soil moisture,SM and PM promoted vegetative growth and increased kernels ha^(-1),the main mechanisms by which SM and PM increased grain yield relative to CK.Relative to PM,SM is a more economically beneficial and environment-friendly technology for dryland wheat production.
基金supported financially by the National Natural Science Foundation of China(Nos.11074195 and 51674181)the Key Projects of Hubei Provincial Department of Education(No.D20151103)
文摘The porous p-type BiSbTebulks containing irregularly and randomly oriented pores were obtained by artificially controlling the relative density of sintered samples during resistance pressing sintering process. It is demonstrated that the thermoelectric performances are significantly affected by the porous structure, especially for the electrical and thermal conductivity due to the enhanced carrier scattering and phonon scattering. The increasing porosity resulted in the obvious decrease in electrical and thermal conductivity, and little change in Seebeck coefficients. It is encouraging that the reduction of thermal conductivity can compensate for the deterioration of electrical performance, leading to the enhancement in thermoelectric figure of merit(ZT). The maximum ZT value of 1.0 was obtained for the sample with a relative density of 90% at 333 K. Unfortunately, the increase in porosity also brought in obvious degradations in Vickers hardness from 51.71 to 27.74 HV. It is worth mentioning that although the Vickers hardness of the sample with a relative density of 90% decreased to 40.12 HV, it was still about twice as high as that of the zone melting sample(21.25 HV). To summarize, introducing pores structure into bulks properly not only enhances the ZT value of BiTebased alloys, but also reduces the use of raw materials and saves production cost.
基金supported by the Liaoning Revitalization Talents Program(Grant No.XLYC2002020)the Major Project of Basic Scientific Research of Chinese Ministry(Grant No.JCYK2016205A003).
文摘Microscopic vision has been widely applied in precision assembly.To achieve sufficiently high resolution in measurements for precision assembly when the sizes of the parts involved exceed the field of view of the vision system,an image mosaic technique must be used.In this paper,a method for constructing an image mosaic with non-overlapping areas with enhanced efficiency is proposed.First,an image mosaic model for the part is created using a geometric model of the measurement system installed on a X-Y-Z precision stages with high repeatability,and a path for image acquisition is established.Second,images are captured along the same path for a specified calibration plate,and an entire image is formed based on the given model.The measurement results obtained from the specified calibration plate are utilized to identify mosaic errors and apply compensation for the part requiring measurement.Experimental results show that the maximum error is less than 4μm for a camera with pixel equivalent 2.46μm,thereby demonstrating the accuracy of the proposed method.This image mosaic technique with non-overlapping regions can simplify image acquisition and reduce the workload involved in constructing an image mosaic.
基金financially supported by the National Natural Science Foundation of China(Nos.41671011,41672355,41871019)the State Key Laboratory of Continental Dynamic,Northwest University,Xi'an,China。
文摘The active deforming southeastern margin of the Tibetan Plateau has developed series of fault basins filled with fluvial-lacustrine sediment deposited by drainage systems during every stage of its uplifting,the records of Cenozoic sedimentary sequence and detrital provenance in these basins are often obscure,making the interpretation of the drainage reorganization quite difficult.This research discovered the earliest Late Cenozoic fluvial conglomerate in the Yuanmou Basin,one of the fault basins in SE Xizang,and named the conglomerate as'the Yuanmou Gravel Layer(YMG)'.Clast petrography,morphology and paleocurrent directions of the YMG indicate that the conglomerate is the remain of a large paleo river traversing through the Yuanmou Basin from north to south.Detrital zircon U-Pb ages can imply the YMG has similar provenance areas with Anning,Dadu and Yalong rivers at age peaks of 175-275,600-1000,and 2100-2700 Ma,but the lack of the age peak of 30-100 Ma from Qiangtang Block implies that the paleo-river was not yet connected with the Jinsha River during the YMG's accumulation.The fluvial-lacustrine strata with gravel beds containing paleosimian fossils comparable to the YMG were deposited~7-11 Ma,further suggesting that the pre-formed south-flowing river was active during the Late Miocene.
基金financed by the National Key Research and Development Program of China [2022YFB3803703]the National Natural Science Foundation of China [52071141, 52271212, 52201250, 51771056]the Interdisciplinary Innovation Program of North China Electric Power University [XM2112355]。
文摘Hydrogen energy is one of the ideal energy alternatives and the upstream of the hydrogen industry chain is hydrogen production,which can be achieved via the reaction of inorganic materials with water,known as hydrolysis.Among inorganic materials,the high hydrogen capacity for hydrolysis of MgH_(2)(15.2 wt%)makes it a promising material for hydrogen production via hydrolysis.However,the dense Mg(OH)_(2) passivation layer will block the reaction between MgH_(2) and the solution,resulting in low hydrogen yield and sluggish hydrolysis kinetics.In this work,the hydrogenyield and hydrogen generation rate of MgH_(2) are considerably enhanced by adding Ti-Zr-Fe-Mn-Cr-V high-entropy alloys(HEAs) for the first time.In particular.the MgH_(2)-3 wt% TiZrFe_(1.5)MnCrV_(0.5)(labelled as MgH_(2)-3 wt% Fe_(1.5)) composite releases 1526.70 mL/g H_(2) within 5 min at 40℃,and the final hydrolysis conversion rate reaches 95.62% within 10 min.The mean hydrogen generation rate of the MgH_(2)-3 wt% Fe_(1.5) composite is 289.16 mL/g/min,which is 2.38 times faster than that of pure MgH_(2).Meanwhile,the activation energy of the MgH_(2)-3 wt% Fe_(1.5) composite is calculated to be 12.53 kJ/mol. The density functional theory(DFT) calculation reveals that the addition of HEAs weakens the Mg-H bonds and accelerates the electron transfer between MgH_(2) and HEAs,Combined with the cocktail effect of HEAs as well as the formation of more interfaces and micro protocells,the hydrolysis performance of MgH_(2) is considerably improved.This work provides an appealing prospect for real-time hydrogen supply and offers a new effective strategy for improving the hydrolysis performance of MgH_(2).
基金supported by the Major Project of National Agricultural Science and Technology of China,the National Natural Science Foundation of China (32171965,32072091,31271750)the Core Technology Development for Breeding Program of Jiangsu Province (JBGS-2021-014)Collaborative Innovation Center for Modern Crop Production Co-sponsored by Province and Ministry (CIC-MCP)Program.
文摘WUSCHEL-related homeobox(WOX)transcription factors play a crucial role in lateral organ development in several plant species;however,their precise functions in soybean(Glycine max[L.]Merr.)were unclear.Here,we identified two independent multi-leaflet soybean mutants,mlw48-8 and mlw48-161,from a CRISPR/Cas9-engineered mutant library in the Williams 82 background.Both mutants exhibited irregular leaf margins,and the upper leaves were narrow and almost lanceolate at maturity.Molecular analysis revealed that these are allelic mutants with independent mutations in the WUSCHEL-related homeobox1(GmWOX1A)gene.A transcriptome analysis demonstrated that GmWOX1A modulates the expression of auxin-and leaf development–related genes.Yeast two-hybrid and split-luciferase complementation imaging assays revealed that GmWOX1A interacts with the YABBY family protein GmYAB5,providing further evidence of its potential involvement in leaf development.Notably,the mlw48-161 mutant showed an increased seed number per plant.Consequently,our study not only provides valuable insights into the role of GmWOX1A in soybean leaf development but also offers a potential strategy for high-yield breeding.
基金This work was supported by the National Natural Science Foundation of China(52007138)Chengdu Technology Innovation R&D Project(2022-YF05-00971-SN).
文摘Pollution flashover is one of themajor insulation accidents that can occur inmodern power systems.If the local arc is not sufficiently elongated by the creepage distance,the flashover performance of the insulator will decrease.The insulator structure and equivalent salt deposition density(ESDD)are the main factors affecting the arc path and length.To investigate the forms of arc paths under different insulator structures and their influence on flashover characteristics,a platformfor recording arc paths is established.This study presents amethod to identify the pattern and distribution of insulator arc paths based on the effect of initial arc on electric field distribution.The results show that there are two main types of local arc paths between umbrellas—the cling-surface arc and the air-jump arc.Moreover,the air-jump arc includes two types—the bridging arc and the gap arc.With the increase in umbrella spacing and ESDD,the probability of arc propagation along the surface increases.The use of the creepage distance can be improved by changing the creepage coefficient to increase the distance between umbrellas.This method has over 90%accuracy.This study is of great significance for improving insulator structure and reducing pollution flashover accidents.
基金supported financially by the Natural Science Foundation of Qinghai(2022-ZJ-928)the Special Project for Transformation of Scientific and Technological Achievements of Qinghai Province(2023-GX-102).
文摘The lamellar hydrates of CAC were designed with the introduction of nano CaCO_(3)or Mg-Al hydrotalcite(M-A-H),and the effects on the green strength,pore structures,and high-temperature fracture behavior of alumina-spinel castables were investigated.The results show that nano CaCO_(3)or M-A-H stimulates rapidly the hydration of CAC and the formation of lamellar C_(4)AcH_(11)or coexistence of C_(2)AH_(8)and C_(4)AcH_(11)at 25℃.The formation of lamellar hydrates can contribute to a more complicated pore structure,especially in the range of 400-2000 nm.Meanwhile,the incorporation of well-distributed CaO or MgO sources from nano CaCO_(3)or M-A-H also regulates the distribution of CA_(6)and spinel(pre-formed and in-situ).Consequently,the optimized microstructure and complicated pore structure can induce the deflection and bridging of cracks,thus facilitating the consumption of fracture energy and enhancing the resistance to thermal stress damage.
