Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+d...Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.展开更多
A novel substrate integrated microstrip to ultra-thin cavity filter transition operating in the W-band is proposed in this letter.The structure is a new method of connecting microstrip circuits and waveguide filters,a...A novel substrate integrated microstrip to ultra-thin cavity filter transition operating in the W-band is proposed in this letter.The structure is a new method of connecting microstrip circuits and waveguide filters,and this new structure enables a planar integrated transition from microstrip lines to ultra-thin cavity filters,thereby reducing the size of the transition structure and achieving miniaturization.The structure includes a conventional tapered microstrip transition structure,which guides the electromagnetic field from the microstrip line to the reduced-height dielectric-filled waveguide,and an air-filled matching cavity which is placed between the dielectric-filled waveguide and the ultra-thin cavity filter.The heights of the microstrip line,the dielectric-filled waveguide and the ultra-thin cavity filter are the same,enabling seamless integration within a planar radio-frequency(RF)circuit.To facilitate testing,mature finline transition structures are integrated at both ends of the microstrip line during fabrications.The simulation results of the fabricated microstrip to ultra-thin cavity filter transition with the finline transition structure,with a passband of 91.5-96.5 GHz,has an insertion loss of less than 1.9 dB and a return loss lower than-20 dB.And the whole structure has also been measured which achieves an insertion loss less than 2.6 dB and a return loss lower than-15 dB within the filter's passband,including the additional insertion loss introduced by the finline transitions.Finally,a W-band compact up-conversion module is designed,and the test results show that after using the proposed structure,the module achieves 95 dBc suppression of the 84 GHz local oscillator.It is also demonstrated that the structure proposed in this letter achieves miniaturization of the system integration without compromising the filter performance.展开更多
The pressure-actuated metal seal with soft metal coating has been widely used in complex working conditions such as high temperature,low temperature and high pressure.The investigation of the characteristics and bindi...The pressure-actuated metal seal with soft metal coating has been widely used in complex working conditions such as high temperature,low temperature and high pressure.The investigation of the characteristics and binding strength of the transition layer between the soft metal coating and the superalloy substrate is important to improve the sealing performance and to model and simplify the working through-process of metal sealing.The distribution characteristics of elements at soft metal-substrate interface and the binding strength between coating and substrate under different thicknesses and material combinations of coating layer were studied by experimental methods.The results indicate that the thickness of soft metal coating has little influence on the interface morphology of GH4169-Cu,GH4169-Ag and Cu-Ag,but has an influence on the thickness of transition layer between different metals,while this influence is weakened with increasing the coating thickness,and the thickness of transition layer is about 2μm when the coating thickness is more than 30μm.The cross-cut test shows that the Cu,Ag and Cu-Ag coatings are all well combined with nickel-based superalloy GH4169 substrate.The materials of soft metal,i.e.the coating materials,have significant influence on the characteristic of transition layer and the surface characteristics of coating after cross-cut test.展开更多
Strain rate is a critical factor influencing the mechanical response of hexagonal close-packed titanium under cryogenic conditions.In this study,uniaxial tensile tests were performed on commercially pure titanium at 7...Strain rate is a critical factor influencing the mechanical response of hexagonal close-packed titanium under cryogenic conditions.In this study,uniaxial tensile tests were performed on commercially pure titanium at 77 K over a broad strain rate range from 0.001 to 1 s^(-1).A critical strain rate of approximately 0.5 s^(-1)was identified,above which ductility exhibits a pronounced reduction,whereas below this threshold,ductility remains relatively stable.Through comprehensive analyses of strain evolution,deformed microstructure,and fracture morphology,this behavior is attributed to severe localized adiabatic heating resulting from inhomogeneous deformation,rather than conventional twin or shear mechanisms.展开更多
We study the average rate of change of energy of two accelerated entangled atoms coupled to electromagnetic fields in the presence of a reflecting boundary,which according to the Dalibard,Dupont-Roc and Cohen-Tannoudj...We study the average rate of change of energy of two accelerated entangled atoms coupled to electromagnetic fields in the presence of a reflecting boundary,which according to the Dalibard,Dupont-Roc and Cohen-Tannoudji formalism is only attributed to the contribution of the radiative reaction of atoms.When the boundary is present,this result can be expressed as the sum of the free-space result and the boundary-induced modifications,and it generally depends on the two-atom initial state,the orientations of atomic dipole moments,as well as the relative scales among atom-boundary distance,interatomic separation and the inverse of atomic acceleration.When the two atoms are vertically aligned and one atom is very close to the boundary,we find that the terms only related to the closer atom are zero for the symmetric state but double the free-space counterpart for the antisymmetric state,if the atom is polarizable parallel to the boundary.However,for the atom polarizable vertically to the boundary,these terms vanish for the antisymmetric state but are twice the free-space counterpart for the symmetric state.Moreover,the terms related to the farther atom exhibit obviously oscillatory behavior,and the terms related to both atoms are vanishing unless the dipole moments of two atoms both have their components vertical to the boundary.When the two atoms are aligned parallel to and very close to the boundary,the terms related to one atom are interatomicseparation-independent and only influenced by the atomic dipole moments.The terms related to both atoms are actually consistent with the counterpart in the vertical-alignment case.In addition,when the two atoms are polarizable along the direction parallel to the boundary,the average rate of change of energy of two parallel-aligned and symmetric entangled atoms vanishes as if the two atoms were a closed system.展开更多
In recent years,the discharge of urea-containing wastewater from industrial and domestic sources has posed a continuing threat to aquatic ecosystems and human health.In this context,the urea oxidation reaction(UOR)has...In recent years,the discharge of urea-containing wastewater from industrial and domestic sources has posed a continuing threat to aquatic ecosystems and human health.In this context,the urea oxidation reaction(UOR)has attracted significant attention due to its low thermodynamic potential of 0.37 V(vs.RHE).Compared with oxygen evolution reaction(OER),this reaction can significantly reduce the energy consumption of electrolysis while realizing wastewater treatment,and has the dual functions of hydrogen energy preparation and wastewater purification.However,UOR involves complex six-electron transfer and intermediate adsorption/desorption processes,resulting in slow reaction kinetics.Therefore,the development of economical and efficient catalysts has become a research focus,among which transition metal phosphides(TMPs)stand out due to their low cost,excellent activity and adjustable electronic structure.Compared with other non-noble metal systems,TMPs have unique electronic structure and surface properties that can adsorb and activate urea molecules more efficiently.However,there is still a lack of systematic reviews on TMP catalysts at present.Therefore,this review aims to deeply and systematically elaborate the design strategies of TMP catalysts and their applications in UOR,thoroughly discuss the current progress,challenges and future directions,and provide theoretical support and design ideas for the development of a new generation of efficient and stable UOR catalysts.展开更多
Natural gas hydrate widely exists in the South China Sea as clean energy.A three-phase transition layer widely exists in low permeability Class I hydrates in the Shenhu offshore area.Therefore,taking into account the ...Natural gas hydrate widely exists in the South China Sea as clean energy.A three-phase transition layer widely exists in low permeability Class I hydrates in the Shenhu offshore area.Therefore,taking into account the low-permeability characteristics with an average permeability of 5.5 mD and moderate heterogeneity,a 3-D geological model of heterogeneous Class I hydrate reservoirs with three-phase transition layers is established by Kriging interpolation and stochastic modeling method,and a numerical simulation model is used to describe the depressurization production performance of the reservoir.With the development of depressurization,a specific range of complete decomposition zones appear both in the hydrate and transition layers.The entire decomposition zone of the whole reservoir tends to outward and upward diffusion.There is apparent methane escape in the three-phase transition layer.Due to the improvement of local permeability caused by the phase transition of hydrate dissociation,some methane accumulation occurs at the bottom of the hydrate layer,forming a local methane enrichment zone.The methane migration trends in reservoirs are mainly characterized by movement toward production wells and hydrate layers under the influence of gravity.However,due to the permeability limitation of hydrate reservoirs,many fluids have not been effectively produced and remain in the reservoir.Therefore,to improve the effective pressure drop of the reservoir,the perforation method and pressure reduction method were optimized by analyzing the influencing factors based on the gas production rate.The comparative study demonstrates that perforating through the free gas layer combined with one-time depressurization can enhance the effective depressurization and improve production performance.The gas production rate from perforating through the free gas layer can be twice as high as that from perforating through the transition layer.This study can provide theoretical support for the utilization of marine energy.展开更多
BACKGROUND Esophageal cancer(ESCA)poses a significant challenge in oncology because of the limited treatment options and poor prognosis.Therefore,enhancing the therapeutic effects of radiotherapy for ESCA and identify...BACKGROUND Esophageal cancer(ESCA)poses a significant challenge in oncology because of the limited treatment options and poor prognosis.Therefore,enhancing the therapeutic effects of radiotherapy for ESCA and identifying relevant therapeutic targets are crucial for improving both the survival rate and quality of life of patients.AIM To define the role of the transcription factor Snail family transcriptional repressor 1(SNAI1)in ESCA,particularly its regulation of radiosensitivity.METHODS A comprehensive analysis of TCGA data assessed SNAI1 expression in ESCA.Survival curves correlated SNAI1 levels with radiotherapy outcomes.Colony formation assays,flow cytometry,and a xenograft model were used to evaluate tumor radiosensitivity and apoptosis.Western blot validated protein expression,while Chromatin im-munoprecipitation assays examined SNAI1's role in regulating epithelial-mesenchymal transition(EMT).RESULTS SNAI1 expression in ESCA cell lines and clinical specimens emphasizes its central role in this disease.Elevated SNAI1 expression is correlated with unfavorable outcomes in radiotherapy.Downregulation of SNAI1 enhances the sensitivity of ESCA cells to ionizing radiation(IR),resulting in remarkable tumor regression upon IR treatment in vivo.This study underscores the direct involvement of SNAI1 in the regulation of EMT,particularly under IR-induced conditions.Furthermore,inhibiting deacetylation effectively suppresses EMT,suggesting a potential avenue to enhance the response to radiotherapy in ESCA.CONCLUSION This study highlights SNAI1's role in ESCA radiosensitivity,offering prognostic insights and therapeutic strategies to enhance radiotherapy by targeting SNAI1 and modulating EMT processes.展开更多
Calculating the inter-layer ion diffusion barrier, a crucial metric for evaluating the rate performance of 2D electrode materials, is time-consuming using the transition state search approach. A novel electrostatic po...Calculating the inter-layer ion diffusion barrier, a crucial metric for evaluating the rate performance of 2D electrode materials, is time-consuming using the transition state search approach. A novel electrostatic potential distribution image (EPDI) transfer learning method has been proposed to efficiently and accurately predict the lithium diffusion barriers on metal element-doped transition metal dichalcogenide (TMD) surfaces. Through the analysis of the mean electrostatic potential (MEP) around binding sites, a positive correlation between binding energy and MEP in VIB-TMDs was identified. Subsequently, transfer learning techniques were used to develop a DenseNet121-TL model for establishing a more accurate mapping between the binding energy and electrostatic potential distribution. Trained on training sets containing 33% and 50% transition state search calculation results, which save 66% and 50% of the calculation time, respectively, the model achieves accurate predictions of the saddle point binding energy with mean absolute errors (MAEs) of 0.0444 and 0.0287 eV on the testing set. Based on the prediction of saddle point binding energies, we obtained a diffusion minimum energy profile with an MAE of 0.0235 eV. Furthermore, by analyzing the diffusion data, we observed that the diffusion barrier was lowered by 10% on V-doped TiS2 compared to the stoichiometric surface. Our findings are expected to provide new insights for the high-throughput calculation of ion diffusion on 2D materials.展开更多
Hydrogen evolution reaction(HER)in acidic media has been spotlighted for hydrogen production since it is a favourable kinetics with the supplied protons from a counterpart compared to that within alkaline environment....Hydrogen evolution reaction(HER)in acidic media has been spotlighted for hydrogen production since it is a favourable kinetics with the supplied protons from a counterpart compared to that within alkaline environment.However,there is no choice but to use a platinum-based catalyst yet.As for a noble metal-free electrocatalyst,incorporation of earth-abundant transition metal(TM)atoms into nanocarbon platforms has been extensively adopted.Although a data-driven methodology facilitates the rational design of TM-anchored carbon catalysts,its practical application suffers from either a simplified theoretical model or the prohibitive cost and complexity of experimental data generation.Herein,an effective and facile catalyst design strategy is proposed based on machine learning(ML)and its model verification using electrochemical methods accompanied by density functional theory simulations.Based on a Bayesian genetic algorithm ML model,the Ni-incorporated carbon quantum dots(Ni@CQD)loaded on a three-dimensional reduced graphene oxide conductor are proposed as the best HER catalyst amongst the various TM-incorporated CQDs under the optimal conditions of catalyst loading,electrode type,and temperature and pH of electrolyte.The ML results are validated with electrochemical experiments,where the Ni@CQD catalyst exhibited superior HER activity,requiring an overpotential of 151 mV to achieve 10 mAcm^(−2) with a Tafel slope of 52 mV dec^(−1) and impressive durability in acidic media up to 100 h.This methodology can provide an effective route for the rational design of highly active electrocatalysts for commercial applications.展开更多
Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen e...Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen evolution reaction(HER)and the anodic oxygen evolution reaction(OER).Transition metal-based catalysts have garnered significant research interest as promising alternatives to noble-metal catalysts,owing to their low cost,tunable composition,and noble-metal-like catalytic activity.Nevertheless,systematic reviews on their application as bifunctional catalysts for overall water splitting(OWS)are still limited.This review comprehensively outlines the principal categories of bifunctional transition metal electrocatalysts derived from electrospun nanofibers(NFs),including metals,oxides,phosphides,sulfides,and carbides.Key strategies for enhancing their catalytic performance are systematically summarized,such as heterointerface engineering,heteroatom doping,metal-nonmetal-metal bridging architectures,and single-atom site design.Finally,current challenges and future research directions are discussed,aiming to provide insightful perspectives for the rational design of high-performance electrocatalysts for OWS.展开更多
Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demo...Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.展开更多
Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate pro-duction.The present work involves the development of a multiphase gas-liquid-solid vertical slug ...Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate pro-duction.The present work involves the development of a multiphase gas-liquid-solid vertical slug flow hydrodynamic model consi-dering hydrate phase transition kinetics with heat and mass transfer behaviors.The varying gas physical properties due to pressure and temperature variations are also introduced to evaluate vertical slug flow characteristics.The proposed model is used to carry out a series of numerical simulations to examine the interactions between hydrate phase transition and vertical slug flow hydrodynamics.Furthermore,the hydrate volumetric fractions under different pressure and temperature conditions are predicted.The results reveal that hydrate formation and gas expansion cause the mixture superficial velocity,and the gas and liquid fractions,void fraction in liq-uid slug,and unit length tend to decrease.The increase in outlet pressure leads to an increased hydrate formation rate,which not only increases the hydrate volumetric fraction along the pipe but also causes the upward shift of the hydrate phase transition critical point.展开更多
BACKGROUND Transition is a critical period for adolescents as they begin to assume responsibility for their own health.Similarly,the shift from pediatric to adult healthcare represents a vulnerable phase,marked by uni...BACKGROUND Transition is a critical period for adolescents as they begin to assume responsibility for their own health.Similarly,the shift from pediatric to adult healthcare represents a vulnerable phase,marked by unique challenges in adolescent health care.Despite its importance,only a few studies have explored healthcare transition among adolescents in Uganda.AIM To identify factors associated with the transition to adult human immunodeficiency virus(HIV)-centered care among adolescents attending HIV/AIDS clinics in Uganda.METHODS A cross-sectional mixed-methods study was conducted among 265 adolescents,randomly selected from three antiretroviral therapy(ART)clinics,using a structured questionnaire.Focus group discussions and key informant interviews were conducted.Individuals aged 10-20 years who were actively enrolled in the ART program between January 4,2022 and January 30,2023 were recruited.The primary outcome of interest was the transition to adult care.Bivariate and multivariate analyses were performed for quantitative data,while content analysis was used to analyze qualitative data.RESULTS The prevalence of transition to adult care was 40.6%.Most participants were male(53.6%)and fell within the 13-15 age group(35.6%).Multivariate logistic regression analysis identified several factors significantly associated with transition to adult care:Age group 10-12 years[prevalence ratio(PR)=2.525,95%CI:2.121-2.944,P=0.002],Age group 13-15 years(PR=1.900,95%CI:1.196-3.416,P=0.001),successful viral load suppression(PR=1.534,95%CI:1.173-1.648,P=0.016),disclosure of HIV status to relatives(PR=5.001,95%CI:3.411-3.611,P=0.000),being prepared for transitioning(PR=5.417,95%CI:3.468-7.135,P=0.041)and having skilled pediatric caregivers(PR=3.724,95%CI:2.084-4.105,P=0.005).CONCLUSION Transition to adult care among adolescents was low.Improving transition outcomes may require strengthening individual support within the family context and integrating transition-focused care into existing specialized clinical settings to enhance the delivery of adolescent-friendly services.展开更多
Fe_(3)Sn_(2),a ferromagnetic metal with a kagome lattice,serves as an ideal platform for exploring topological electronic states and Berry curvature due to its unique band structure.However,systematic reports on the t...Fe_(3)Sn_(2),a ferromagnetic metal with a kagome lattice,serves as an ideal platform for exploring topological electronic states and Berry curvature due to its unique band structure.However,systematic reports on the transport properties of Fe_(3)Sn_(2)nanosheets remain scarce.We present temperature-dependent transport property measurements of Fe_(3)Sn_(2)nanosheets synthesized via chemical vapor deposition on Si/SiO_(2)substrates.The samples exhibit a robust anomalous Hall effect from 40 K to 300 K,along with a magnetoresistance sign reversal at 40 K at high magnetic fields,indicating a spin reorientation from in-plane to out-of-plane.Notably,a sharp crossover in the dominant transport contribution from electrons to holes near 200 K is observed,accompanied by distinct anomalous Hall behaviors in the two regimes,indicating a temperature-induced Lifshitz transition within the multi-band system.This divergence is potentially linked to a topological reconstruction of the Fermi surface across the transition.Our findings highlight the tunability of topological transport in two-dimensional kagome magnets and provide new insights into the interplay between band topology,dimensionality and magnetic order.展开更多
[Objectives]To investigate the effects of different planting densities and nitrogen application rates on the yield and quality of the tobacco cultivar Chuxue 80.[Methods]A field experiment was conducted in Hubei Provi...[Objectives]To investigate the effects of different planting densities and nitrogen application rates on the yield and quality of the tobacco cultivar Chuxue 80.[Methods]A field experiment was conducted in Hubei Province,evaluating various combinations of planting density and nitrogen rate for Chuxue 80.[Results]At the maturity stage,the TN1 treatment(5 kg N per 667 m^(2) with a density of 1900 plants per 667 m^(2))demonstrated the most favorable agronomic performance.The TN9 treatment(11 kg N per 667 m^(2) with a density of 1110 plants per 667 m^(2))achieved the highest wrapper tobacco yield and output value.Meanwhile,the TN5 treatment(8 kg N per 667 m^(2) with a density of 1515 plants per 667 m^(2))resulted in the best smoking quality.[Conclusions]The TN9 treatment,with a planting density of 1110 plants per 667 m^(2) and a nitrogen application rate of 11 kg per 667 m^(2),is recommended as the optimal cultivation practice for Chuxue 80 in Hubei Province.展开更多
The high-alloyed wrought superalloy GH4975 tends to form coarse MC carbides and eutectic(γ+γ′)phases,which adversely affect the cogging and homogenization process.To provide theoretical guidance for control of MC c...The high-alloyed wrought superalloy GH4975 tends to form coarse MC carbides and eutectic(γ+γ′)phases,which adversely affect the cogging and homogenization process.To provide theoretical guidance for control of MC carbides and eutectic(γ+γ′)formation,differential thermal analysis(DTA)was utilized to investigate the effect of cooing rate(10-90℃·min^(-1))on solidification behavior and micro-segregation of GH4975 alloy.According to the thermodynamic calculation and distribution characteristics of precipitates,the MC carbides can act as nucleation sites forγdendrites,but the nucleation ofγdendrites becomes less dependent on the MC carbide primers at higher cooling rates.As theγdendrites grow,the elements including Ti and Nb gradually accumulate in the residual liquid and leads to the formation of more MC carbides near the interdendritic region.Finally,the solidification is terminated with the formation of eutectic(γ+γ′).With an increase in cooling rate,the liquidus temperature rises,but the solidus temperature decreases,and thus the solidification range is obviously enlarged.The dendritic structure is significantly refined by the increase of cooling rate.The secondary dendrite arm spacing,λ_(2),as a function of cooling rate,T,can be expressed asλ_(2)=216.78T^(-0.42).Moreover,the increasing cooling rate weakens the back diffusion of Al,Ti,and Nb,increases the undercooling,and limits the growth of precipitates.Consequently,the sizes of MC carbides,eutectic(γ+γ′),and primaryγ′significantly decrease,but the area fraction of eutectic(γ+γ′)linerly increases as the cooling rate rises.Thus moderate cooling rate(such as 30℃·min^(-1))should be selected during the solidification process of GH4975 alloy.展开更多
Silicosis is one of the most serious and prevalent occupational diseases globally,characterized by typical silicotic nodules and fibrosis.Recent studies suggest that the perinodular zone of the lung shares certain cha...Silicosis is one of the most serious and prevalent occupational diseases globally,characterized by typical silicotic nodules and fibrosis.Recent studies suggest that the perinodular zone of the lung shares certain characteristics with the nodules themselves.In this study,a silicotic rat model was established via a single intratracheal in-stillation of a 50 mg/mL silica suspension.Pulmonary anatomical and pathological examinations revealed that silica deposition induced severe alterations in both the nodular and perinodular tissues.Subsequently,pseudo-targeted metabolomics analysis revealed that abnormally elevated ornithine levels were closely associated with the progression of silicosis,from normal to perinodular and finally to nodular tissues.Immunofluorescent stain-ing demonstrated that,in addition to M2 macrophages,silica exposure increased the protein levels of ARG1 in epithelial cells,a finding further confirmed by in vitro experiments using A549 and BEAS-2B cells.Moreover,accumulated ornithine induced epithelial-mesenchymal transition in vitro,increased extracellular matrix expres-sion in NIH 3T3 fibroblasts,and enhanced TGF-β1 levels in RAW264.7 cells.Co-exposure to ornithine and silica significantly induced the aberrant expression of fibrosis-associated proteins compared to silica exposure alone,characterized by increased levels of FN and𝛼-SMA,as well as decreased E-cad expression.These findings sug-gest that silica exposure up-regulates ARG1 in various cells,leading to ornithine accumulation,which in turn accelerates the progression of fibrosis.展开更多
The thermal decomposition characteristic of ammonium perchlorate(AP)represents a critical factor in determining the performance of solid propellants,which has aroused significant interest on the structure and performa...The thermal decomposition characteristic of ammonium perchlorate(AP)represents a critical factor in determining the performance of solid propellants,which has aroused significant interest on the structure and performance improvement of kinds of catalysts.In this study,bimetallic metal-organic frameworks(MOFs),such as CuCo-BTC(BTC=1,3,5-Benzenetricarboxylic acid,H_(3)BTC),CuNi-BTC,and CoNi-BTC,were synthesized by solvothermal(ST)and spray-drying(SD)methods,and then calcined at 400℃for 2 h to form metal oxides.The catalysts as well as their catalytic effects for AP decomposition were characterized by FTIR,XRD,SEM,XPS,TG,DSC,TG-IR,EIS,CV,and LSV.It was found that the rapid coordination of metal ions with ligands during spray drying may lead to catalytic structural defects,promoting the exposure of reactive active sites and increasing the catalytic active region.The results showed that the addition of 2 wt%binary transition metal oxides(BTMOs)as catalysts significantly reduced the high-temperature decomposition(HTD)temperature of AP and enhanced its heat release.Of particular significance is the observation that SD-CoNiO_(x),prepared by spray-drying,reduced the decomposition temperature of AP from 413.26℃(pure AP)to 306℃and enhanced the heat release from 256.79 J/g(pure AP)to 1496.82 J/g,while concomitantly reducing the activation energy by 42%.By analysing the gaseous products during the decomposition of AP+SD-CoNiO_(x)and AP+ST-CoNiO_(x),it was found that SD-CoNiO_(x)could significantly increase the content of high-valent nitrogen oxides during the AP decomposition reaction,which indicates that the BTMOs prepared by spray-drying in the reaction system are more conducive to accelerating the electron transfer in the thermal decomposition process of AP,and can provide a high concentration of reactive oxygen species that oxidize AP to high-valent nitrogen oxide-containing compounds.The present study shows that the structure selectivity of the spray-drying technique influences surfactant molecular arrangement on catalyst surfaces,resulting in their ability to promote higher electron transfer during the catalytic process.Therefore,BTMOs prepared by spray drying method have higher potential for application.展开更多
基金supported by the National Natural Science Foundation of China(No.21805018)by Sichuan Science and Technology Program(Nos.2022ZHCG0018,2023NSFSC0117 and 2023ZHCG0060)Yibin Science and Technology Program(No.2022JB005)and China Postdoctoral Science Foundation(No.2022M722704).
文摘Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.
基金Supported by the Fundamental Research Funds for the Central Universities(ZYGX2021J008)。
文摘A novel substrate integrated microstrip to ultra-thin cavity filter transition operating in the W-band is proposed in this letter.The structure is a new method of connecting microstrip circuits and waveguide filters,and this new structure enables a planar integrated transition from microstrip lines to ultra-thin cavity filters,thereby reducing the size of the transition structure and achieving miniaturization.The structure includes a conventional tapered microstrip transition structure,which guides the electromagnetic field from the microstrip line to the reduced-height dielectric-filled waveguide,and an air-filled matching cavity which is placed between the dielectric-filled waveguide and the ultra-thin cavity filter.The heights of the microstrip line,the dielectric-filled waveguide and the ultra-thin cavity filter are the same,enabling seamless integration within a planar radio-frequency(RF)circuit.To facilitate testing,mature finline transition structures are integrated at both ends of the microstrip line during fabrications.The simulation results of the fabricated microstrip to ultra-thin cavity filter transition with the finline transition structure,with a passband of 91.5-96.5 GHz,has an insertion loss of less than 1.9 dB and a return loss lower than-20 dB.And the whole structure has also been measured which achieves an insertion loss less than 2.6 dB and a return loss lower than-15 dB within the filter's passband,including the additional insertion loss introduced by the finline transitions.Finally,a W-band compact up-conversion module is designed,and the test results show that after using the proposed structure,the module achieves 95 dBc suppression of the 84 GHz local oscillator.It is also demonstrated that the structure proposed in this letter achieves miniaturization of the system integration without compromising the filter performance.
基金National Natural Science Foundation of China(52375378)National Key Laboratory of Metal Forming Technology and Heavy Equipment(S2308100.W12)Huxiang High-Level Talent Gathering Project of Hunan Province(2021RC5001)。
文摘The pressure-actuated metal seal with soft metal coating has been widely used in complex working conditions such as high temperature,low temperature and high pressure.The investigation of the characteristics and binding strength of the transition layer between the soft metal coating and the superalloy substrate is important to improve the sealing performance and to model and simplify the working through-process of metal sealing.The distribution characteristics of elements at soft metal-substrate interface and the binding strength between coating and substrate under different thicknesses and material combinations of coating layer were studied by experimental methods.The results indicate that the thickness of soft metal coating has little influence on the interface morphology of GH4169-Cu,GH4169-Ag and Cu-Ag,but has an influence on the thickness of transition layer between different metals,while this influence is weakened with increasing the coating thickness,and the thickness of transition layer is about 2μm when the coating thickness is more than 30μm.The cross-cut test shows that the Cu,Ag and Cu-Ag coatings are all well combined with nickel-based superalloy GH4169 substrate.The materials of soft metal,i.e.the coating materials,have significant influence on the characteristic of transition layer and the surface characteristics of coating after cross-cut test.
基金financially supported by the National Key Research&Development Plan(No.2022YFE0110600)the National Natural Science Foundation of China(Nos.52171117,52371113,92263201 and 52175306)+3 种基金Qing Lan Project(No.54944004)the Basic Research Program of Jiangsu(Nos.BK20232011 and BK20232025)the Postdoctoral Fellowship Program of CPSF(No.GZC20233481)Tuoyuan project of Nanjing Tech University(No.20230113)
文摘Strain rate is a critical factor influencing the mechanical response of hexagonal close-packed titanium under cryogenic conditions.In this study,uniaxial tensile tests were performed on commercially pure titanium at 77 K over a broad strain rate range from 0.001 to 1 s^(-1).A critical strain rate of approximately 0.5 s^(-1)was identified,above which ductility exhibits a pronounced reduction,whereas below this threshold,ductility remains relatively stable.Through comprehensive analyses of strain evolution,deformed microstructure,and fracture morphology,this behavior is attributed to severe localized adiabatic heating resulting from inhomogeneous deformation,rather than conventional twin or shear mechanisms.
基金supported in part by the NSFC under Grant Nos.12047551 and 12105061the Graduate Innovation Project of Shanxi Normal University under Grant No.2023XSY041。
文摘We study the average rate of change of energy of two accelerated entangled atoms coupled to electromagnetic fields in the presence of a reflecting boundary,which according to the Dalibard,Dupont-Roc and Cohen-Tannoudji formalism is only attributed to the contribution of the radiative reaction of atoms.When the boundary is present,this result can be expressed as the sum of the free-space result and the boundary-induced modifications,and it generally depends on the two-atom initial state,the orientations of atomic dipole moments,as well as the relative scales among atom-boundary distance,interatomic separation and the inverse of atomic acceleration.When the two atoms are vertically aligned and one atom is very close to the boundary,we find that the terms only related to the closer atom are zero for the symmetric state but double the free-space counterpart for the antisymmetric state,if the atom is polarizable parallel to the boundary.However,for the atom polarizable vertically to the boundary,these terms vanish for the antisymmetric state but are twice the free-space counterpart for the symmetric state.Moreover,the terms related to the farther atom exhibit obviously oscillatory behavior,and the terms related to both atoms are vanishing unless the dipole moments of two atoms both have their components vertical to the boundary.When the two atoms are aligned parallel to and very close to the boundary,the terms related to one atom are interatomicseparation-independent and only influenced by the atomic dipole moments.The terms related to both atoms are actually consistent with the counterpart in the vertical-alignment case.In addition,when the two atoms are polarizable along the direction parallel to the boundary,the average rate of change of energy of two parallel-aligned and symmetric entangled atoms vanishes as if the two atoms were a closed system.
基金financially supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01E38).
文摘In recent years,the discharge of urea-containing wastewater from industrial and domestic sources has posed a continuing threat to aquatic ecosystems and human health.In this context,the urea oxidation reaction(UOR)has attracted significant attention due to its low thermodynamic potential of 0.37 V(vs.RHE).Compared with oxygen evolution reaction(OER),this reaction can significantly reduce the energy consumption of electrolysis while realizing wastewater treatment,and has the dual functions of hydrogen energy preparation and wastewater purification.However,UOR involves complex six-electron transfer and intermediate adsorption/desorption processes,resulting in slow reaction kinetics.Therefore,the development of economical and efficient catalysts has become a research focus,among which transition metal phosphides(TMPs)stand out due to their low cost,excellent activity and adjustable electronic structure.Compared with other non-noble metal systems,TMPs have unique electronic structure and surface properties that can adsorb and activate urea molecules more efficiently.However,there is still a lack of systematic reviews on TMP catalysts at present.Therefore,this review aims to deeply and systematically elaborate the design strategies of TMP catalysts and their applications in UOR,thoroughly discuss the current progress,challenges and future directions,and provide theoretical support and design ideas for the development of a new generation of efficient and stable UOR catalysts.
基金supported by the Sinopec Technology Research and Development Project(No.30000000-22-ZC0607-0235,No.33550000-22-ZC0607-0009)the National Natural Science Foundation of China(No.52334002).
文摘Natural gas hydrate widely exists in the South China Sea as clean energy.A three-phase transition layer widely exists in low permeability Class I hydrates in the Shenhu offshore area.Therefore,taking into account the low-permeability characteristics with an average permeability of 5.5 mD and moderate heterogeneity,a 3-D geological model of heterogeneous Class I hydrate reservoirs with three-phase transition layers is established by Kriging interpolation and stochastic modeling method,and a numerical simulation model is used to describe the depressurization production performance of the reservoir.With the development of depressurization,a specific range of complete decomposition zones appear both in the hydrate and transition layers.The entire decomposition zone of the whole reservoir tends to outward and upward diffusion.There is apparent methane escape in the three-phase transition layer.Due to the improvement of local permeability caused by the phase transition of hydrate dissociation,some methane accumulation occurs at the bottom of the hydrate layer,forming a local methane enrichment zone.The methane migration trends in reservoirs are mainly characterized by movement toward production wells and hydrate layers under the influence of gravity.However,due to the permeability limitation of hydrate reservoirs,many fluids have not been effectively produced and remain in the reservoir.Therefore,to improve the effective pressure drop of the reservoir,the perforation method and pressure reduction method were optimized by analyzing the influencing factors based on the gas production rate.The comparative study demonstrates that perforating through the free gas layer combined with one-time depressurization can enhance the effective depressurization and improve production performance.The gas production rate from perforating through the free gas layer can be twice as high as that from perforating through the transition layer.This study can provide theoretical support for the utilization of marine energy.
基金Supported by the National Key R&D Program of China,No.2022YFC2503700 and No.2022YFC2503703the National Health Commission Key Laboratory of Nuclear Technology Medical Transformation(Mianyang Central Hospital),No.2023HYX005.
文摘BACKGROUND Esophageal cancer(ESCA)poses a significant challenge in oncology because of the limited treatment options and poor prognosis.Therefore,enhancing the therapeutic effects of radiotherapy for ESCA and identifying relevant therapeutic targets are crucial for improving both the survival rate and quality of life of patients.AIM To define the role of the transcription factor Snail family transcriptional repressor 1(SNAI1)in ESCA,particularly its regulation of radiosensitivity.METHODS A comprehensive analysis of TCGA data assessed SNAI1 expression in ESCA.Survival curves correlated SNAI1 levels with radiotherapy outcomes.Colony formation assays,flow cytometry,and a xenograft model were used to evaluate tumor radiosensitivity and apoptosis.Western blot validated protein expression,while Chromatin im-munoprecipitation assays examined SNAI1's role in regulating epithelial-mesenchymal transition(EMT).RESULTS SNAI1 expression in ESCA cell lines and clinical specimens emphasizes its central role in this disease.Elevated SNAI1 expression is correlated with unfavorable outcomes in radiotherapy.Downregulation of SNAI1 enhances the sensitivity of ESCA cells to ionizing radiation(IR),resulting in remarkable tumor regression upon IR treatment in vivo.This study underscores the direct involvement of SNAI1 in the regulation of EMT,particularly under IR-induced conditions.Furthermore,inhibiting deacetylation effectively suppresses EMT,suggesting a potential avenue to enhance the response to radiotherapy in ESCA.CONCLUSION This study highlights SNAI1's role in ESCA radiosensitivity,offering prognostic insights and therapeutic strategies to enhance radiotherapy by targeting SNAI1 and modulating EMT processes.
基金supported by the National Natural Science Foundation of China(Nos.51974056 and 51474047)the Foundation of the Supercomputing Center of Dalian University of Technology,and the Foundation of the Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province),China.
文摘Calculating the inter-layer ion diffusion barrier, a crucial metric for evaluating the rate performance of 2D electrode materials, is time-consuming using the transition state search approach. A novel electrostatic potential distribution image (EPDI) transfer learning method has been proposed to efficiently and accurately predict the lithium diffusion barriers on metal element-doped transition metal dichalcogenide (TMD) surfaces. Through the analysis of the mean electrostatic potential (MEP) around binding sites, a positive correlation between binding energy and MEP in VIB-TMDs was identified. Subsequently, transfer learning techniques were used to develop a DenseNet121-TL model for establishing a more accurate mapping between the binding energy and electrostatic potential distribution. Trained on training sets containing 33% and 50% transition state search calculation results, which save 66% and 50% of the calculation time, respectively, the model achieves accurate predictions of the saddle point binding energy with mean absolute errors (MAEs) of 0.0444 and 0.0287 eV on the testing set. Based on the prediction of saddle point binding energies, we obtained a diffusion minimum energy profile with an MAE of 0.0235 eV. Furthermore, by analyzing the diffusion data, we observed that the diffusion barrier was lowered by 10% on V-doped TiS2 compared to the stoichiometric surface. Our findings are expected to provide new insights for the high-throughput calculation of ion diffusion on 2D materials.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(NRF-2022R1A2C1011559,No.RS-2024-00405818 and NRF-2021M3H4A6A01045764)by the National Supercomputing Center with supercomputing resources including technical support(KSC-2024-CRE-0196)by Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Science and ICT(No.RS-2024-00404712).
文摘Hydrogen evolution reaction(HER)in acidic media has been spotlighted for hydrogen production since it is a favourable kinetics with the supplied protons from a counterpart compared to that within alkaline environment.However,there is no choice but to use a platinum-based catalyst yet.As for a noble metal-free electrocatalyst,incorporation of earth-abundant transition metal(TM)atoms into nanocarbon platforms has been extensively adopted.Although a data-driven methodology facilitates the rational design of TM-anchored carbon catalysts,its practical application suffers from either a simplified theoretical model or the prohibitive cost and complexity of experimental data generation.Herein,an effective and facile catalyst design strategy is proposed based on machine learning(ML)and its model verification using electrochemical methods accompanied by density functional theory simulations.Based on a Bayesian genetic algorithm ML model,the Ni-incorporated carbon quantum dots(Ni@CQD)loaded on a three-dimensional reduced graphene oxide conductor are proposed as the best HER catalyst amongst the various TM-incorporated CQDs under the optimal conditions of catalyst loading,electrode type,and temperature and pH of electrolyte.The ML results are validated with electrochemical experiments,where the Ni@CQD catalyst exhibited superior HER activity,requiring an overpotential of 151 mV to achieve 10 mAcm^(−2) with a Tafel slope of 52 mV dec^(−1) and impressive durability in acidic media up to 100 h.This methodology can provide an effective route for the rational design of highly active electrocatalysts for commercial applications.
基金Supported by the National Natural Science Foundation of China(No.52273056)the Science and Technology Development Program of Jilin Province,China(No.YDZJ202501ZYTS305)。
文摘Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen evolution reaction(HER)and the anodic oxygen evolution reaction(OER).Transition metal-based catalysts have garnered significant research interest as promising alternatives to noble-metal catalysts,owing to their low cost,tunable composition,and noble-metal-like catalytic activity.Nevertheless,systematic reviews on their application as bifunctional catalysts for overall water splitting(OWS)are still limited.This review comprehensively outlines the principal categories of bifunctional transition metal electrocatalysts derived from electrospun nanofibers(NFs),including metals,oxides,phosphides,sulfides,and carbides.Key strategies for enhancing their catalytic performance are systematically summarized,such as heterointerface engineering,heteroatom doping,metal-nonmetal-metal bridging architectures,and single-atom site design.Finally,current challenges and future research directions are discussed,aiming to provide insightful perspectives for the rational design of high-performance electrocatalysts for OWS.
基金supported by the National Key Research and Development Program of China(No.2018YFA0703700)the National Natural Science Foundation of China(No.12034002)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities,No.FRF-IDRY-23-033)。
文摘Amorphous two-dimensional transition metal oxide/(oxy)hydroxide(2D TMO/TMHO)nanomaterials(NMs)have the properties of both 2D and amorphous materials,displaying outstanding physicochemical qualities.Therefore,they demonstrate considerable promise for use in electrocatalytic water splitting applications.Here,the primary amorphization strategies for achieving the 2D TMO/TMHO NMs are comprehensively reviewed,including low-temperature reaction,rapid reaction,exchange/doping effect,ligand modulation,and interfacial energy confinement.By integrating these strategies with various physicochemical synthesis methods,it is feasible to control the amorphization of TMO/TMHO NMs while maintaining the distinctive benefits of their 2D structures.Furthermore,it delves into the structural advantages of amorphous 2D TMO/TMHO NMs in electrocatalytic water splitting,particularly emphasizing recent advancements in enhancing their electrocatalytic performance through interface engineering.The challenges and potential future directions for the precise synthesis and practical application of amorphous 2D TMO/TMHO NMs are also provided.This review aims to establish a theoretical foundation and offer experimental instructions for developing effective and enduring electrocatalysts for water splitting.
基金supported by the National Natural Science Foundation of China(No.52301355)the Natu-ral Science Foundation of Qingdao Municipality(No.23-2-1-108-zyyd-jch)the China University of Petroleum(East China)Independent Innovation Research Project(Science and Engineering)-Leading Talent Cultivation Fund(No.24CX07001A).
文摘Hydrate phase transition may pose risks in pipeline blockage and severe challenges for offshore natural gas hydrate pro-duction.The present work involves the development of a multiphase gas-liquid-solid vertical slug flow hydrodynamic model consi-dering hydrate phase transition kinetics with heat and mass transfer behaviors.The varying gas physical properties due to pressure and temperature variations are also introduced to evaluate vertical slug flow characteristics.The proposed model is used to carry out a series of numerical simulations to examine the interactions between hydrate phase transition and vertical slug flow hydrodynamics.Furthermore,the hydrate volumetric fractions under different pressure and temperature conditions are predicted.The results reveal that hydrate formation and gas expansion cause the mixture superficial velocity,and the gas and liquid fractions,void fraction in liq-uid slug,and unit length tend to decrease.The increase in outlet pressure leads to an increased hydrate formation rate,which not only increases the hydrate volumetric fraction along the pipe but also causes the upward shift of the hydrate phase transition critical point.
文摘BACKGROUND Transition is a critical period for adolescents as they begin to assume responsibility for their own health.Similarly,the shift from pediatric to adult healthcare represents a vulnerable phase,marked by unique challenges in adolescent health care.Despite its importance,only a few studies have explored healthcare transition among adolescents in Uganda.AIM To identify factors associated with the transition to adult human immunodeficiency virus(HIV)-centered care among adolescents attending HIV/AIDS clinics in Uganda.METHODS A cross-sectional mixed-methods study was conducted among 265 adolescents,randomly selected from three antiretroviral therapy(ART)clinics,using a structured questionnaire.Focus group discussions and key informant interviews were conducted.Individuals aged 10-20 years who were actively enrolled in the ART program between January 4,2022 and January 30,2023 were recruited.The primary outcome of interest was the transition to adult care.Bivariate and multivariate analyses were performed for quantitative data,while content analysis was used to analyze qualitative data.RESULTS The prevalence of transition to adult care was 40.6%.Most participants were male(53.6%)and fell within the 13-15 age group(35.6%).Multivariate logistic regression analysis identified several factors significantly associated with transition to adult care:Age group 10-12 years[prevalence ratio(PR)=2.525,95%CI:2.121-2.944,P=0.002],Age group 13-15 years(PR=1.900,95%CI:1.196-3.416,P=0.001),successful viral load suppression(PR=1.534,95%CI:1.173-1.648,P=0.016),disclosure of HIV status to relatives(PR=5.001,95%CI:3.411-3.611,P=0.000),being prepared for transitioning(PR=5.417,95%CI:3.468-7.135,P=0.041)and having skilled pediatric caregivers(PR=3.724,95%CI:2.084-4.105,P=0.005).CONCLUSION Transition to adult care among adolescents was low.Improving transition outcomes may require strengthening individual support within the family context and integrating transition-focused care into existing specialized clinical settings to enhance the delivery of adolescent-friendly services.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1403503,2022YFA1602802,2023YFA1607400,and 2024YFA1613200)Beijing Natural Science Foundation(Grant No.JQ23022)supported by the Synergetic Extreme Condition User Facility and the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302600)。
文摘Fe_(3)Sn_(2),a ferromagnetic metal with a kagome lattice,serves as an ideal platform for exploring topological electronic states and Berry curvature due to its unique band structure.However,systematic reports on the transport properties of Fe_(3)Sn_(2)nanosheets remain scarce.We present temperature-dependent transport property measurements of Fe_(3)Sn_(2)nanosheets synthesized via chemical vapor deposition on Si/SiO_(2)substrates.The samples exhibit a robust anomalous Hall effect from 40 K to 300 K,along with a magnetoresistance sign reversal at 40 K at high magnetic fields,indicating a spin reorientation from in-plane to out-of-plane.Notably,a sharp crossover in the dominant transport contribution from electrons to holes near 200 K is observed,accompanied by distinct anomalous Hall behaviors in the two regimes,indicating a temperature-induced Lifshitz transition within the multi-band system.This divergence is potentially linked to a topological reconstruction of the Fermi surface across the transition.Our findings highlight the tunability of topological transport in two-dimensional kagome magnets and provide new insights into the interplay between band topology,dimensionality and magnetic order.
基金Supported by Science and Technology Project of China Tobacco Zhejiang Industrial Co.,Ltd.(2023330000340093).
文摘[Objectives]To investigate the effects of different planting densities and nitrogen application rates on the yield and quality of the tobacco cultivar Chuxue 80.[Methods]A field experiment was conducted in Hubei Province,evaluating various combinations of planting density and nitrogen rate for Chuxue 80.[Results]At the maturity stage,the TN1 treatment(5 kg N per 667 m^(2) with a density of 1900 plants per 667 m^(2))demonstrated the most favorable agronomic performance.The TN9 treatment(11 kg N per 667 m^(2) with a density of 1110 plants per 667 m^(2))achieved the highest wrapper tobacco yield and output value.Meanwhile,the TN5 treatment(8 kg N per 667 m^(2) with a density of 1515 plants per 667 m^(2))resulted in the best smoking quality.[Conclusions]The TN9 treatment,with a planting density of 1110 plants per 667 m^(2) and a nitrogen application rate of 11 kg per 667 m^(2),is recommended as the optimal cultivation practice for Chuxue 80 in Hubei Province.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52474362,52174317 and 51904146)the General Project Funded by Liaoning Province Education Department(Grant No.JYTMS20230943)。
文摘The high-alloyed wrought superalloy GH4975 tends to form coarse MC carbides and eutectic(γ+γ′)phases,which adversely affect the cogging and homogenization process.To provide theoretical guidance for control of MC carbides and eutectic(γ+γ′)formation,differential thermal analysis(DTA)was utilized to investigate the effect of cooing rate(10-90℃·min^(-1))on solidification behavior and micro-segregation of GH4975 alloy.According to the thermodynamic calculation and distribution characteristics of precipitates,the MC carbides can act as nucleation sites forγdendrites,but the nucleation ofγdendrites becomes less dependent on the MC carbide primers at higher cooling rates.As theγdendrites grow,the elements including Ti and Nb gradually accumulate in the residual liquid and leads to the formation of more MC carbides near the interdendritic region.Finally,the solidification is terminated with the formation of eutectic(γ+γ′).With an increase in cooling rate,the liquidus temperature rises,but the solidus temperature decreases,and thus the solidification range is obviously enlarged.The dendritic structure is significantly refined by the increase of cooling rate.The secondary dendrite arm spacing,λ_(2),as a function of cooling rate,T,can be expressed asλ_(2)=216.78T^(-0.42).Moreover,the increasing cooling rate weakens the back diffusion of Al,Ti,and Nb,increases the undercooling,and limits the growth of precipitates.Consequently,the sizes of MC carbides,eutectic(γ+γ′),and primaryγ′significantly decrease,but the area fraction of eutectic(γ+γ′)linerly increases as the cooling rate rises.Thus moderate cooling rate(such as 30℃·min^(-1))should be selected during the solidification process of GH4975 alloy.
基金supported by the National Natural Science Foundation of China(No.81973466)the National Administration of Traditional Chinese Medicine Youth Qihuang Scholars Support Project,and the Program of Graduate Innovation Research in Shanxi Province(No.2023KY019).
文摘Silicosis is one of the most serious and prevalent occupational diseases globally,characterized by typical silicotic nodules and fibrosis.Recent studies suggest that the perinodular zone of the lung shares certain characteristics with the nodules themselves.In this study,a silicotic rat model was established via a single intratracheal in-stillation of a 50 mg/mL silica suspension.Pulmonary anatomical and pathological examinations revealed that silica deposition induced severe alterations in both the nodular and perinodular tissues.Subsequently,pseudo-targeted metabolomics analysis revealed that abnormally elevated ornithine levels were closely associated with the progression of silicosis,from normal to perinodular and finally to nodular tissues.Immunofluorescent stain-ing demonstrated that,in addition to M2 macrophages,silica exposure increased the protein levels of ARG1 in epithelial cells,a finding further confirmed by in vitro experiments using A549 and BEAS-2B cells.Moreover,accumulated ornithine induced epithelial-mesenchymal transition in vitro,increased extracellular matrix expres-sion in NIH 3T3 fibroblasts,and enhanced TGF-β1 levels in RAW264.7 cells.Co-exposure to ornithine and silica significantly induced the aberrant expression of fibrosis-associated proteins compared to silica exposure alone,characterized by increased levels of FN and𝛼-SMA,as well as decreased E-cad expression.These findings sug-gest that silica exposure up-regulates ARG1 in various cells,leading to ornithine accumulation,which in turn accelerates the progression of fibrosis.
基金supported by the National Natural ScienceFoundation of China(Grant No.52203332)。
文摘The thermal decomposition characteristic of ammonium perchlorate(AP)represents a critical factor in determining the performance of solid propellants,which has aroused significant interest on the structure and performance improvement of kinds of catalysts.In this study,bimetallic metal-organic frameworks(MOFs),such as CuCo-BTC(BTC=1,3,5-Benzenetricarboxylic acid,H_(3)BTC),CuNi-BTC,and CoNi-BTC,were synthesized by solvothermal(ST)and spray-drying(SD)methods,and then calcined at 400℃for 2 h to form metal oxides.The catalysts as well as their catalytic effects for AP decomposition were characterized by FTIR,XRD,SEM,XPS,TG,DSC,TG-IR,EIS,CV,and LSV.It was found that the rapid coordination of metal ions with ligands during spray drying may lead to catalytic structural defects,promoting the exposure of reactive active sites and increasing the catalytic active region.The results showed that the addition of 2 wt%binary transition metal oxides(BTMOs)as catalysts significantly reduced the high-temperature decomposition(HTD)temperature of AP and enhanced its heat release.Of particular significance is the observation that SD-CoNiO_(x),prepared by spray-drying,reduced the decomposition temperature of AP from 413.26℃(pure AP)to 306℃and enhanced the heat release from 256.79 J/g(pure AP)to 1496.82 J/g,while concomitantly reducing the activation energy by 42%.By analysing the gaseous products during the decomposition of AP+SD-CoNiO_(x)and AP+ST-CoNiO_(x),it was found that SD-CoNiO_(x)could significantly increase the content of high-valent nitrogen oxides during the AP decomposition reaction,which indicates that the BTMOs prepared by spray-drying in the reaction system are more conducive to accelerating the electron transfer in the thermal decomposition process of AP,and can provide a high concentration of reactive oxygen species that oxidize AP to high-valent nitrogen oxide-containing compounds.The present study shows that the structure selectivity of the spray-drying technique influences surfactant molecular arrangement on catalyst surfaces,resulting in their ability to promote higher electron transfer during the catalytic process.Therefore,BTMOs prepared by spray drying method have higher potential for application.
