High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-co...High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-corrected transmission electron microscopy constrain resolution.A machine learning algorithm is developed to determine the aberration parameters with higher precision from small,lattice-periodic crystal images.The proposed algorithm is then validated with simulated HRTEM images of graphene and applied to the experimental images of a molybdenum disulfide(MoS_(2))monolayer with 25 variables(14 aberrations)resolved in wide ranges.Using these measured parameters,the phases of the exit-wave functions are reconstructed for each image in a focal series of MoS_(2)monolayers.The images were acquired due to the unexpected movement of the specimen holder.Four-dimensional data extraction reveals time-varying atomic structures and ripple.In particular,the atomic evolution of the sulfur-vacancy point and line defects,as well as the edge structure near the amorphous,is visualized as the resolution has been improved from about 1.75?to 0.9 A.This method can help salvage important transmission electron microscope images and is beneficial for the images obtained from electron microscopes with average stability.展开更多
An experimental investigation of the dynamics of the interface between two low-viscosity fluids with high density contrast oscillating in a fixed vertical slotted channel has been conducted.It has been found that as t...An experimental investigation of the dynamics of the interface between two low-viscosity fluids with high density contrast oscillating in a fixed vertical slotted channel has been conducted.It has been found that as the amplitude of the liquid column oscillations increases,parametric oscillations of the interface are excited in the form of a standing wave located in the channel plane.In particular,depending on the interfacial tension,the standing waves have a frequency equal to that of liquid piston oscillations(harmonic response),or half of the frequency of oscillations of the liquid column in the channel(subharmonic response).The detected type of instability has a gravitational-capillary nature and is analogous to Faraday waves.The analysis of the overcritical dynamics of wave oscillations indicates that interfacial tension plays a crucial role in determining the type of parametric instability.At high interfacial tension,only synchronous(harmonic)wave modes are observed,and the threshold of the wave excitation is determined by the amplitude of piston oscillations of the liquid column.In this case,the oscillation acceleration does not play a role and has a small value in the threshold of the synchronous mode response.In the case of weak surface tension,subharmonic oscillations are observed.The threshold for the development of these oscillations is determined by the dimensionless acceleration of the oscillating liquid column and remains almost constant with variations in the dimensionless frequency of oscillations.At moderate values of interfacial tension(in the region of moderate dimensionless frequencies),a synchronous wave mode emerges in the stability threshold of the oscillating interface.As the dimensionless acceleration is increased further,a subharmonic mode is excited.The growth of subharmonic oscillations occurs against the background of harmonic wave oscillations,with the oscillations of the interface representing a combination of two standing waves.展开更多
Iron-chromium flow batteries(ICRFBs)have emerged as an ideal large-scale energy storage device with broad application prospects in recent years.Enhancement of the Cr^(3+)/Cr^(2+)redox reaction activity and inhibition ...Iron-chromium flow batteries(ICRFBs)have emerged as an ideal large-scale energy storage device with broad application prospects in recent years.Enhancement of the Cr^(3+)/Cr^(2+)redox reaction activity and inhibition of the hydrogen evolution side reaction(HER)are essential for the development of ICRFBs and require a novel catalyst design.However,elucidating the underlying mechanisms for modulating catalyst behaviors remains an unresolved challenge.Here,we show a novel precisely controlled preparation of a novel thermal-treated carbon cloth electrode with a uniform deposit of low-cost indium catalyst particles.The density functional theory analysis reveals the In catalyst has a significant adsorption effect on the reactants and improves the redox reaction activity of Cr^(3+)/Cr^(2+).Moreover,H+is more easily absorbed on the surface of the catalyst with a high migration energy barrier,thereby inhibiting the occurrence of HER.The assembled ICRFBs have an average energy efficiency of 83.91%at 140 mA cm^(-2),and this method minimizes the electrodeposition process and cleans the last obstacle for industry long cycle operation requirements.The ICRFBs exhibit exceptional long-term stability with an energy efficiency decay rate of 0.011%per cycle at 1000 cycles,the lowest ICRFBs reported so far.Therefore,this study provides a promising strategy for developing ICRFBs with low costs and long cycle life.展开更多
The effects of synthesis conditions,especially the heating rate,on the reaction kinetics of Ni-rich cathodes were systematically studied.The growth rate of Ni-rich oxide increases continuously as the heating rate incr...The effects of synthesis conditions,especially the heating rate,on the reaction kinetics of Ni-rich cathodes were systematically studied.The growth rate of Ni-rich oxide increases continuously as the heating rate increases.Ab initio molecular dynamics simulations demonstrate that a high heating rate induces anabatic oscillations,indicating a decrease in thermodynamic stability and a tendency for the crystal surface to undergo reconstruction.The presence of an intermediate phase at the grain boundary amplifies atomic migration-induced interface fusion and consequently augments crystal growth kinetics.However,the excessively high heating rate aggravates the Li+/Ni2+mixing in the Ni-rich cathode.The single-crystal Ni-rich cathode exhibits enhanced structural/thermal stability but a decreased specific capacity and rate performance compared with its polycrystalline counterpart.展开更多
The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods t...The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods to address the cooling challenge for high-power devices in DCs.Hybrid nanofluid(HNF)has the advantages of high thermal conductivity and good rheological properties.This study summarizes the numerical investigations of HNFs in mini/micro heat sinks,including the numerical methods,hydrothermal characteristics,and enhanced heat transfer technologies.The innovations of this paper include:(1)the characteristics,applicable conditions,and scenarios of each theoretical method and numerical method are clarified;(2)the molecular dynamics(MD)simulation can reveal the synergy effect,micro motion,and agglomeration morphology of different nanoparticles.Machine learning(ML)presents a feasiblemethod for parameter prediction,which provides the opportunity for the intelligent regulation of the thermal performance of HNFs;(3)the HNFs flowboiling and the synergy of passive and active technologies may further improve the overall efficiency of liquid cooling systems in DCs.This review provides valuable insights and references for exploring the multi-phase flow and heat transport mechanisms of HNFs,and promoting the practical application of HNFs in chip-level liquid cooling in DCs.展开更多
Ohmic contacts are fundamental components in semiconductor technology,facilitating efficient electrical connection and excellent device performance.We employ first-principles calculations to show that semimetallic gra...Ohmic contacts are fundamental components in semiconductor technology,facilitating efficient electrical connection and excellent device performance.We employ first-principles calculations to show that semimetallic graphene is a natural Ohmic contact partner of monolayer semiconducting black arsenic(BAs),for which the top of the valence band is below the Fermi energy of the order of 10~2 meV.The Ohmic contact arises from the giant Stark effect induced by van der Waals electron transfer from BAs to graphene,which does not destroy their respective band features.Remarkably,we show that this intrinsic Ohmic contact remains robust across a wide range of interlayer distances(adjustable by strain)or vertical electric fields,whereas the weak spin splitting of the order of 1 meV induced by symmetry breaking plays little part in Ohmic contact.These findings reveal the potential applications of graphene–BAs in ultralow dissipation transistors.展开更多
In order to address challenges posed by the reduction in transistor size,researchers are concentrating on two-dimensional(2D)materials with high dielectric constants and large band gaps.Monoclinic ZrO_(2)(m-ZrO_(2))ha...In order to address challenges posed by the reduction in transistor size,researchers are concentrating on two-dimensional(2D)materials with high dielectric constants and large band gaps.Monoclinic ZrO_(2)(m-ZrO_(2))has emerged as a promising gate dielectric material due to its suitable dielectric constant,wide band gap,ideal valence-band offset,and good thermodynamic stability.However,current deposition methods face compatibility issues with 2D semiconductors,highlighting the need for high-quality dielectrics and interfaces.Here,high-quality 2D m-ZrO_(2)single crystals are successfully prepared using a onestep chemical vapor deposition(CVD)method,aided by 5A molecular sieves for oxygen supply.The prepared ZrO_(2)is utilized as a gate dielectric in the construction of MoS2 field-effect transistors(FETs)to investigate its electrical property.The FETs exhibit a high carrier mobility of up to 5.50 cm^(2)·V^(−1)·s^(−1),and a current switching ratio(Ion/off)of approximately 10^(4),which aligns with the current standards of logic circuits,indicating that ZrO_(2)has application value as a gate dielectric.The successful onestep preparation of single-crystal ZrO_(2)paves the way for the utilization of high-κgate dielectrics and creates favorable conditions for the development of high-performance semiconductor devices,offering new possibilities for transistor miniaturization.展开更多
Realizing the point-of-care tumor markers biodetection with good convenience and high sensitivity possesses great significance for prompting cancer monitoring and screening in biomedical study field.Herein,the quantum...Realizing the point-of-care tumor markers biodetection with good convenience and high sensitivity possesses great significance for prompting cancer monitoring and screening in biomedical study field.Herein,the quantum dots luminescence and microfluidic biochip with machine vision algorithm-based intelligent biosensing platform have been designed and manufactured for point-of-care tumor markers diagnostics.The employed quantum dots with excellent photoluminescent performance are modified with specific antibody as the optical labeling agents for the designed sandwich structure immunoassay.The corresponding biosensing investigations of the designed biodetection platform illustrate several advantages involving high sensitivity(~0.021 ng mL^(−1)),outstanding accessibility,and great integrability.Moreover,related test results of human-sourced artificial saliva samples demonstrate better detection capabilities compared with commercially utilized rapid test strips.Combining these infusive abilities,our elaborate biosensing platform is expected to exhibit potential applications for the future point-of-care tumor markers diagnostic area.展开更多
The stability of perovskite solar cells(PSCs)is adversely affected by nonradiative recombination resulting from buried interface defects.Herein,we synthesize a polyionic liquid,poly(p-vinylbenzyl trimethylam-monium he...The stability of perovskite solar cells(PSCs)is adversely affected by nonradiative recombination resulting from buried interface defects.Herein,we synthesize a polyionic liquid,poly(p-vinylbenzyl trimethylam-monium hexafluorophosphate)(PTA),and introduce it into the buried interface of PSCs.The quaternary ammonium cation(N(-CH_(3))^(3+))in PTA can fill the vacancies of organic cations within the perovskite structure and reduce shallow energy level defects.Additionally,the hexafluorophosphate(PF6−)in PTA forms a Lewis acid-base interaction with Pb^(2+)in the perovskite layer,effectively passivating deep en-ergy level defects.Furthermore,hydrogen bonding can be established between organic cations and the PF6−anion,preventing the formation of shallow energy level defects.Through this synergistic mecha-nism,the deep and shallow energy level defects are effectively mitigated,resulting in improved device performance.As a result,the resulting treated inverted PSC exhibits an impressive power conversion ef-ficiency(PCE)of 24.72%.Notably,the PTA-treated PSCs exhibit remarkable stability,with 88.5%of the original PCE retained after undergoing heat aging at 85℃ for 1078 h,and 89.1%of the initial PCE main-tained following continuous exposure to light for 1100 h at the maximum power point.Synergistically suppressing multiple defects at the buried interface through the use of polyionic liquids is a promising way to improve the commercial viability of PSCs.展开更多
Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(T...Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(TENGs)stand out as a prominent device capitalizing on the principles of triboelectrification and electrostatic induction to generate electricity or electrical signals.In efforts to augment the electrical output performance of TENGs and broaden their range of applications,researchers have endeavored to refine materials,surface morphology,and structural design.Among them,physical morphological modifications play a pivotal role in enhancing the electrical properties of TENGs by increasing the contact surface area,which can be achieved by building micro-/nano-structures on the surface or inside the friction material.In this review,we summarize the common morphologies of TENGs,categorize the morphologies into surface and internal structures,and elucidate their roles in enhancing the electric output performance of devices.Moreover,we systematically classify the methodologies employed for morphological preparation into physical and chemical approaches,thereby furnishing a comprehensive survey of the diverse techniques.Subsequently,typical applications of TENGs with special morphology divided by energy harvesting and self-powered sensors are presented.Finally,an overview of the challenges and future trajectories pertinent to TENGs is conducted.Through this endeavor,the aim of this article is to catalyze the evolution of further strategies for enhancing performance of TENGs.展开更多
Air pollution,a critical environmental issue,necessitates urgent action.It originates from both human activities,like industrial emissions and vehicle pollution,and natural events such as sandstorms,leading to increas...Air pollution,a critical environmental issue,necessitates urgent action.It originates from both human activities,like industrial emissions and vehicle pollution,and natural events such as sandstorms,leading to increased atmospheric pollutants such as sulfur dioxide(SO_(2)),nitrogen dioxide(NO_(2)),ammonia ion(NH_(4)^(+)),black carbon,ozone,and fine particulate matter(PM_(2.5)).Leveraging China's extensive air quality monitoring data,artificial intelligence(AI)was used in this study to enhance air quality prediction and management.The study aims to utilize the vast air monitoring data more effectively by developing advanced air quality assessment methods and AI models.An AI-based method presented in this study was applied to train extensive air quality data,enabling an intelligent air quality index(AQI)that swiftly and accurately reflects air quality status,to assess impacts on sensitive groups,and to predict future trends.This smart prediction and optimization(SPO)approach not only utilizes existing monitoring network data efficiently but also offers precise future air quality forecasts,providing valuable strategies for pollution prevention and air quality improvement.Data on various pollutants were collected from four regions in China between August 2021 and July 2022,using diverse modeling techniques and machine learning methodologies.The models achieved a high accuracy level of around 99%,indicating the significant portion of air quality that falls into the unhealthy category,especially impacting sensitive groups and reflecting the adverse atmospheric conditions in the studied regions.展开更多
We have investigated the magnetic, dielectric, pyroelectric, and thermal expansion properties of a layered perovskite metal–organic framework, [NH_(4)Cl]_(2)[Ni(HCOO)_(2)(NH_(3))_(2)]. The material undergoes three ph...We have investigated the magnetic, dielectric, pyroelectric, and thermal expansion properties of a layered perovskite metal–organic framework, [NH_(4)Cl]_(2)[Ni(HCOO)_(2)(NH_(3))_(2)]. The material undergoes three phase transitions including a canted antiferromagnetic transition at ~36 K, and two successive structural transitions around 100 K and 110 K, respectively. The temperature dependence of dielectric permittivity and pyroelectric current suggests that the structural transitions induce weak ferroelectricity along the c-axis and antiferroelectricity in the ab plane. A negative thermal expansion along the c-axis is observed between two structural phase transitions, which is ascribed to the abnormal shrinkage of interlayer hydrogen bonding length. Moreover, the ferroelectric/antiferroelectric phase transition temperature shifts towards a higher temperature under a magnetic field, suggesting certain magnetoelectric coupling in the paramagnetic phase. Our study suggests that the layered metal–organic frameworks provide a unique playground for exploring exotic physical properties such as multiferroicity and abnormal thermal expansion.展开更多
The attosecond extreme ultraviolet(XUV) pulse pump and femtosecond infrared(IR) pulse probe scheme is commonly used to study the dynamics and attosecond transient absorption(ATA) spectra of microscopic systems. In a r...The attosecond extreme ultraviolet(XUV) pulse pump and femtosecond infrared(IR) pulse probe scheme is commonly used to study the dynamics and attosecond transient absorption(ATA) spectra of microscopic systems. In a recent report [Proc. Natl. Acad. Sci. USA 121 e2307836121(2024)], we showed that shaped XUV pulses with spectral minima can significantly alter the absorption line shape of helium's 2s2p doubly excited state within a few tens of attoseconds.However, it remains unclear if similar effects could be observed in a singly excited state. In this study, we use shaped XUV pulses to excite helium's 2p singly excited state and couple the 2p and 3d states with a delayed IR pulse. Comparing these results with those from Gaussian XUV pulses, we find that the ATA spectra for the shaped XUV pulses exhibit more pronounced changes with delay, while the changes for the Gaussian pulses are gradual. We also explain these differences through population changes and analytical models. Our findings show that shaped XUV pulses can regulate the dynamics and absorption spectra of a singly excited state.展开更多
Transition metal(oxy)hydroxides are potential oxygen evolution reaction(OER)electrocatalysts;however,simultaneously modulating multiple factors to enhance their performance is a grand challenge.Here,we report an incor...Transition metal(oxy)hydroxides are potential oxygen evolution reaction(OER)electrocatalysts;however,simultaneously modulating multiple factors to enhance their performance is a grand challenge.Here,we report an incorporating heteroatom strategy via one-step hydrothermal approach to adjust more than one factor of Mn-doped NiFe(oxy)hydroxide(Mn-NiFeOOH/LDH)heterojunction.Mn doping regulates heterojunction morphology(reducing nanoparticles and becoming thinner and denser nanosheets),Ni/Fe ratio and valence states(Ni^(2+),Ni^(3+),and Ni^(3+Δ))of Ni ions.The former could effectively increase surface active sites,and the latter two reduce the content of Fe in the Mnx-NiFeOOH/LDH heterojunction,en-abling more Ni^(2+)convert to Ni^(3+/3+Δ)that have higher intrinsic OER activity.As a result,the first-rank Mn-NiFeOOH/LDH with ultra-low overpotential of 185 mV@20 mA cm^(-2) and 296 mV@500 mA cm^(-2),and the improved OER performance are outdo to those of commercial RuO_(2) catalyst for OER.Moreover,the Mn-NiFeOOH/LDH affords the earliest initial potential(1.392 V vs.RHE),corresponds to a recorded low overpotential(162 mV).Based on the density functional theory(DFT),Mn dopants can alter intermedi-ate adsorption energy and effectively decrease∗OOH’s energy barrier.This research exhibits a feasible strategy to design low cost electrocatalysts and provide new possibilities for future industrialization.展开更多
The construction of intermetallic compounds(IMCs)connection layers with special compositions by adding small amounts of alloying elements has been proven to be an effective strategy for improving the reliability of el...The construction of intermetallic compounds(IMCs)connection layers with special compositions by adding small amounts of alloying elements has been proven to be an effective strategy for improving the reliability of electronic component interconnect.However,the synergistic effect mechanism of multi-component alloy compositions on the growth behavior of IMCs is not clear.Herein,we successfully prepared a new quaternary alloy solder with a composition of Sn-0.7Cu-0.175Pt-0.025Al(wt%)using the high-throughput screening(HTS)method.The results showed that it possesses excellent welding performance with an inhibition rate over 40%on the growth of IMCs layers.For Cu_(6)Sn_(5),the co-doping of Al and Pt not only greatly improves its thermodynamic stability,but also effectively suppresses the phase transition.Meanwhile,the co-doping of Al and Pt also significantly delays the generation time of Kirkendall defects.The substitution sites of Al and Pt in Cu_(6)Sn_(5)have been explored using atomic resolution imaging and advanced data informatics,indicating that Al and Pt preferentially substitute Sn and Cu atoms,respectively,to generate(Cu,Pt)_(6)(Sn,Al)_(5).A one-dimensional(1D)kinetic model of the IMCs layer growth at the Sn solder/Cu substrate interface was derived and validated,and the results showed that the error of the derived mathematical model is less than 5%.Finally,the synergistic mechanism of Al and Pt co-doping on the growth rate of Cu_(6)Sn_(5)was further elucidated.This work provides a feasible route for the design and development of multi-component alloy solders.展开更多
The careful observation and evaluation of the squamocolumnar junction(SCJ)are essential requirements in colposcopy procedures.While traditional colposcopes with visible light offer high resolution and sensitivity,the ...The careful observation and evaluation of the squamocolumnar junction(SCJ)are essential requirements in colposcopy procedures.While traditional colposcopes with visible light offer high resolution and sensitivity,the presence of glare patterns on the cervix limits the visualization of deeper tissue features.Cross-polarization imaging,on the other hand,overcomes this limitation by effectively removing glare and providing greater optical penetration depth to noninvasively examine subsurface tissue structures.In this study,we present the potential of polarized light in enhancing diagnostics through cross-polarization imaging for the identification and contrast enhancement of squamous and columnar epithelium(CE)in cases of cervical ectropion.Our results demonstrate that polarized light colposcopy offers valuable diagnostic information that complements traditional colposcopy.By effectively reducing glare and improving visibility during cervical examinations,polarized light colposcopy proves to be a useful tool.Furthermore,we introduce a novel method that practically enhances the contrast ratio(CR)between columnar and squamous epithelium(SE)in colposcopic images.This method significantly increases the contrast between these tissue types,facilitating clearer differentiation and improving diagnostic accuracy.Notably,the combination of the cross-polarization imaging technique with our proposed algorithm enables the clear observation of the SCJ boundary.These findings emphasize the potential of our approach in enhancing the accuracy and effectiveness of polarized colposcopy for evaluating cervical tissue.展开更多
Transition metal dichalcogenides(TMDs)have emerged as promising electrocatalysts for various electrocatalytic processes.Molybdenum disulfide has been widely used,but a single electrocatalyst can hardly be applied to a...Transition metal dichalcogenides(TMDs)have emerged as promising electrocatalysts for various electrocatalytic processes.Molybdenum disulfide has been widely used,but a single electrocatalyst can hardly be applied to all reactions,making it essential to understand the electrochemistry of selected TMDs.Tungsten diselenide(WSe_(2))is reactive in gas evolution processes,similar to molybdenum,yet has received limited attention.This work explores how different exfoliation powers affect WSe_(2)structural configurations and their impact on catalytic performance in hydrogen evolution,oxygen evolution,and capacitive behaviour.The study investigates the structural properties of WSe_(2)nanosheets in both liquid(dispersion)and solid(electrode)phases.Low exfoliation power(90.4 W)contributes to well-defined WSe_(2),while higher power(814 W)leads to an increased number of selenium vacancies.These modifications influence key properties such as thickness,band gaps(1.518 to 1.578 eV),exfoliation yield(0.27 to 0.12 mg mL^(-1)),and oxide content(44.3%to 53.9%),resulting in distinct electrochemical behaviours in different electrolytes.WSe_(2)nanosheets exfoliated at higher power exhibit reduced activity in the hydrogen evolution reaction(HER)due to the loss of W–Se bonds and the formation of an amorphous structure,but they show enhanced oxygen evolution reaction(OER)performance,particularly in alkaline media.Additionally,a higher concentration of selenium vacancies improves capacitive performance in acidic conditions due to proton contributions but are less favourable in neutral and basic electrolytes.This study highlights the importance of exfoliation power in tuning the structural properties of WSe_(2)for specific electrochemical applications,advancing the understanding of its synthesis and performance.展开更多
Ferroelectric materials find extensive applications in brake systems due to their capability to convert electrical energy into mechanical energy.Recent research has focused on lead-free materials for their environment...Ferroelectric materials find extensive applications in brake systems due to their capability to convert electrical energy into mechanical energy.Recent research has focused on lead-free materials for their environmentally friendly characteristics.However,they exhibit several challenges such as significant negative strain,limited strain values,and large driving field.In this work,novel preparation techniques(electrospinning)were utilized for BaTiO_(3)to introduce oxygen vacancies and barium defects,facilitating the creation of oriented defect dipoles coupled with an intrinsic electric field(Ei)after poling and aging.Due to the existence of Ei,two minimum points in the strain hysteresis loop were shifted to the same quadrant in the Strain-Electric field space.Thus,when applying an electric field along the Ei direction,negative strain is eliminated.Additionally,the actual electric field is the sum of the applied electric field and Ei,thereby reducing the required driving field of the piezoelectric.The stretching of defect dipoles under the electric field further amplified the total strain.Through the proposed mechanisms,this work achieved a substantial unipolar electrostrain of 1.04%under a relatively low electric field(30 kV/cm)in BaTiO_(3).This work successfully addressed the challenges of high-driving electric fields,limited strain values,and negative strain,providing a comprehensive approach for improving field-induced strain performance through point defect engineering in ferroelectric materials.展开更多
Chitosan(CS)-based nanocomposites have been studied in various fields,requiring a more facile and efficient technique to fabricate nanoparticles with customized structures.In this study,Ag@methacrylamide CS/poly(ethyl...Chitosan(CS)-based nanocomposites have been studied in various fields,requiring a more facile and efficient technique to fabricate nanoparticles with customized structures.In this study,Ag@methacrylamide CS/poly(ethylene glycol)diacrylate(Ag@MP)micropatterns are successfully fabricated by femtosecond laser maskless optical projection lithography(Fs-MOPL)for the first time.The formation mechanism of core-shell nanomaterial is demonstrated by the local surface plasmon resonances and the nucleation and growth theory.Amino and hydroxyl groups greatly affect the number of Ag@MP nanocomposites,which is further verified by replacing MCS with methacrylated bovine serum albumin and hyaluronic acid methacryloyl,respectively.Besides,the performance of the surface-enhanced Raman scattering,cytotoxicity,cell proliferation,and antibacterial was investigated on Ag@MP micropatterns.Therefore,the proposed protocol to prepare hydrogel core-shell micropattern by the home-built Fs-MOPL technique is prospective for potential applications in the biomedical and biotechnological fields,such as biosensors,cell imaging,and antimicrobial.展开更多
Ni-rich LiNi0.8Mn0.1Co0.1O2(NCM)cathodes in layered oxide cathodes are attractive for high-energy lithium-ion batteries but suffer from rapid capacity fade and thermal instability at high charge voltages.In this study...Ni-rich LiNi0.8Mn0.1Co0.1O2(NCM)cathodes in layered oxide cathodes are attractive for high-energy lithium-ion batteries but suffer from rapid capacity fade and thermal instability at high charge voltages.In this study,we propose an entropy-assisted multi-element doping strategy to mitigate these issues.Specifically,two routes are designed and compared:bulk-like localized high-entropy doping(BHE-NCM)and surface-distributed high-entropy-zone doping(SHE-NCM).The surface entropy-doped NCM cathode delivers enhanced electrochemical performance,including higher capacity retention under 4.5 V cycling and superior rate capability,compared to both bulk-like and pristine counterparts.Comprehensive material characterization reveals that surface-localized doping stabilizes the layered structure with reduced microcrack formation and creates a uniform dopant-rich surface region with improved thermal and electrochemical stability.Overall,entropy-assisted doping at the near surface zone effectively alleviates structural degradation and interface reactions in Ni-rich NCM,enabling improved cycling performance at high voltage.This work highlights the significance of surface entropy engineering as a promising strategy for designing high-voltage cathodes with improved safety and longevity.展开更多
基金financial support from the National Natural Science Foundation of China(Grant No.61971201)。
文摘High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-corrected transmission electron microscopy constrain resolution.A machine learning algorithm is developed to determine the aberration parameters with higher precision from small,lattice-periodic crystal images.The proposed algorithm is then validated with simulated HRTEM images of graphene and applied to the experimental images of a molybdenum disulfide(MoS_(2))monolayer with 25 variables(14 aberrations)resolved in wide ranges.Using these measured parameters,the phases of the exit-wave functions are reconstructed for each image in a focal series of MoS_(2)monolayers.The images were acquired due to the unexpected movement of the specimen holder.Four-dimensional data extraction reveals time-varying atomic structures and ripple.In particular,the atomic evolution of the sulfur-vacancy point and line defects,as well as the edge structure near the amorphous,is visualized as the resolution has been improved from about 1.75?to 0.9 A.This method can help salvage important transmission electron microscope images and is beneficial for the images obtained from electron microscopes with average stability.
基金supported by the Ministry of Education of the Russian Federation(Project No.1023032300071-6-2.3.1).
文摘An experimental investigation of the dynamics of the interface between two low-viscosity fluids with high density contrast oscillating in a fixed vertical slotted channel has been conducted.It has been found that as the amplitude of the liquid column oscillations increases,parametric oscillations of the interface are excited in the form of a standing wave located in the channel plane.In particular,depending on the interfacial tension,the standing waves have a frequency equal to that of liquid piston oscillations(harmonic response),or half of the frequency of oscillations of the liquid column in the channel(subharmonic response).The detected type of instability has a gravitational-capillary nature and is analogous to Faraday waves.The analysis of the overcritical dynamics of wave oscillations indicates that interfacial tension plays a crucial role in determining the type of parametric instability.At high interfacial tension,only synchronous(harmonic)wave modes are observed,and the threshold of the wave excitation is determined by the amplitude of piston oscillations of the liquid column.In this case,the oscillation acceleration does not play a role and has a small value in the threshold of the synchronous mode response.In the case of weak surface tension,subharmonic oscillations are observed.The threshold for the development of these oscillations is determined by the dimensionless acceleration of the oscillating liquid column and remains almost constant with variations in the dimensionless frequency of oscillations.At moderate values of interfacial tension(in the region of moderate dimensionless frequencies),a synchronous wave mode emerges in the stability threshold of the oscillating interface.As the dimensionless acceleration is increased further,a subharmonic mode is excited.The growth of subharmonic oscillations occurs against the background of harmonic wave oscillations,with the oscillations of the interface representing a combination of two standing waves.
基金support from the National Natural Science Foundation of China(No.22308378,22308380,22393963)the Science Foundation of China University of Petroleum,Beijing(No.2462023XKBH005,ZX20230078).
文摘Iron-chromium flow batteries(ICRFBs)have emerged as an ideal large-scale energy storage device with broad application prospects in recent years.Enhancement of the Cr^(3+)/Cr^(2+)redox reaction activity and inhibition of the hydrogen evolution side reaction(HER)are essential for the development of ICRFBs and require a novel catalyst design.However,elucidating the underlying mechanisms for modulating catalyst behaviors remains an unresolved challenge.Here,we show a novel precisely controlled preparation of a novel thermal-treated carbon cloth electrode with a uniform deposit of low-cost indium catalyst particles.The density functional theory analysis reveals the In catalyst has a significant adsorption effect on the reactants and improves the redox reaction activity of Cr^(3+)/Cr^(2+).Moreover,H+is more easily absorbed on the surface of the catalyst with a high migration energy barrier,thereby inhibiting the occurrence of HER.The assembled ICRFBs have an average energy efficiency of 83.91%at 140 mA cm^(-2),and this method minimizes the electrodeposition process and cleans the last obstacle for industry long cycle operation requirements.The ICRFBs exhibit exceptional long-term stability with an energy efficiency decay rate of 0.011%per cycle at 1000 cycles,the lowest ICRFBs reported so far.Therefore,this study provides a promising strategy for developing ICRFBs with low costs and long cycle life.
基金funded by the National Natural Science Foundation of China(No.22379052)Taishan Scholars of Shandong Province,China(No.tsqnz20221143)。
文摘The effects of synthesis conditions,especially the heating rate,on the reaction kinetics of Ni-rich cathodes were systematically studied.The growth rate of Ni-rich oxide increases continuously as the heating rate increases.Ab initio molecular dynamics simulations demonstrate that a high heating rate induces anabatic oscillations,indicating a decrease in thermodynamic stability and a tendency for the crystal surface to undergo reconstruction.The presence of an intermediate phase at the grain boundary amplifies atomic migration-induced interface fusion and consequently augments crystal growth kinetics.However,the excessively high heating rate aggravates the Li+/Ni2+mixing in the Ni-rich cathode.The single-crystal Ni-rich cathode exhibits enhanced structural/thermal stability but a decreased specific capacity and rate performance compared with its polycrystalline counterpart.
基金funded by the Science and Technology Project of Tianjin(No.24YDTPJC00680)the National Natural Science Foundation of China(No.52406191).
文摘The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods to address the cooling challenge for high-power devices in DCs.Hybrid nanofluid(HNF)has the advantages of high thermal conductivity and good rheological properties.This study summarizes the numerical investigations of HNFs in mini/micro heat sinks,including the numerical methods,hydrothermal characteristics,and enhanced heat transfer technologies.The innovations of this paper include:(1)the characteristics,applicable conditions,and scenarios of each theoretical method and numerical method are clarified;(2)the molecular dynamics(MD)simulation can reveal the synergy effect,micro motion,and agglomeration morphology of different nanoparticles.Machine learning(ML)presents a feasiblemethod for parameter prediction,which provides the opportunity for the intelligent regulation of the thermal performance of HNFs;(3)the HNFs flowboiling and the synergy of passive and active technologies may further improve the overall efficiency of liquid cooling systems in DCs.This review provides valuable insights and references for exploring the multi-phase flow and heat transport mechanisms of HNFs,and promoting the practical application of HNFs in chip-level liquid cooling in DCs.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62374088 and 12074193)。
文摘Ohmic contacts are fundamental components in semiconductor technology,facilitating efficient electrical connection and excellent device performance.We employ first-principles calculations to show that semimetallic graphene is a natural Ohmic contact partner of monolayer semiconducting black arsenic(BAs),for which the top of the valence band is below the Fermi energy of the order of 10~2 meV.The Ohmic contact arises from the giant Stark effect induced by van der Waals electron transfer from BAs to graphene,which does not destroy their respective band features.Remarkably,we show that this intrinsic Ohmic contact remains robust across a wide range of interlayer distances(adjustable by strain)or vertical electric fields,whereas the weak spin splitting of the order of 1 meV induced by symmetry breaking plays little part in Ohmic contact.These findings reveal the potential applications of graphene–BAs in ultralow dissipation transistors.
基金support from the National Natural Science Foundation of China(No.21975067)Shenzhen Science and Technology Program(No.JCYJ20220530160407016).
文摘In order to address challenges posed by the reduction in transistor size,researchers are concentrating on two-dimensional(2D)materials with high dielectric constants and large band gaps.Monoclinic ZrO_(2)(m-ZrO_(2))has emerged as a promising gate dielectric material due to its suitable dielectric constant,wide band gap,ideal valence-band offset,and good thermodynamic stability.However,current deposition methods face compatibility issues with 2D semiconductors,highlighting the need for high-quality dielectrics and interfaces.Here,high-quality 2D m-ZrO_(2)single crystals are successfully prepared using a onestep chemical vapor deposition(CVD)method,aided by 5A molecular sieves for oxygen supply.The prepared ZrO_(2)is utilized as a gate dielectric in the construction of MoS2 field-effect transistors(FETs)to investigate its electrical property.The FETs exhibit a high carrier mobility of up to 5.50 cm^(2)·V^(−1)·s^(−1),and a current switching ratio(Ion/off)of approximately 10^(4),which aligns with the current standards of logic circuits,indicating that ZrO_(2)has application value as a gate dielectric.The successful onestep preparation of single-crystal ZrO_(2)paves the way for the utilization of high-κgate dielectrics and creates favorable conditions for the development of high-performance semiconductor devices,offering new possibilities for transistor miniaturization.
基金supported by grants from the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.CRF No.PolyU C5110-20G)PolyU Grants(1-CE0H,1-W30M,1-CD4S).
文摘Realizing the point-of-care tumor markers biodetection with good convenience and high sensitivity possesses great significance for prompting cancer monitoring and screening in biomedical study field.Herein,the quantum dots luminescence and microfluidic biochip with machine vision algorithm-based intelligent biosensing platform have been designed and manufactured for point-of-care tumor markers diagnostics.The employed quantum dots with excellent photoluminescent performance are modified with specific antibody as the optical labeling agents for the designed sandwich structure immunoassay.The corresponding biosensing investigations of the designed biodetection platform illustrate several advantages involving high sensitivity(~0.021 ng mL^(−1)),outstanding accessibility,and great integrability.Moreover,related test results of human-sourced artificial saliva samples demonstrate better detection capabilities compared with commercially utilized rapid test strips.Combining these infusive abilities,our elaborate biosensing platform is expected to exhibit potential applications for the future point-of-care tumor markers diagnostic area.
基金supported by the Science,Technology,and Innovation Commission of Shenzhen Municipality(No.GJHZ20220913143204008)the Shccig-Qinling Program(No.SMYJY202300294C)+3 种基金National Natural Science Foundation of China(Nos.22261142666,52372225,52172237,22305191)the Shaanxi Science Fund for Distinguished Young Scholars(No.2022JC-21)the Research Fund of the State Key Laboratory of Solidification Processing(NPU)China(No.2021-QZ-02).
文摘The stability of perovskite solar cells(PSCs)is adversely affected by nonradiative recombination resulting from buried interface defects.Herein,we synthesize a polyionic liquid,poly(p-vinylbenzyl trimethylam-monium hexafluorophosphate)(PTA),and introduce it into the buried interface of PSCs.The quaternary ammonium cation(N(-CH_(3))^(3+))in PTA can fill the vacancies of organic cations within the perovskite structure and reduce shallow energy level defects.Additionally,the hexafluorophosphate(PF6−)in PTA forms a Lewis acid-base interaction with Pb^(2+)in the perovskite layer,effectively passivating deep en-ergy level defects.Furthermore,hydrogen bonding can be established between organic cations and the PF6−anion,preventing the formation of shallow energy level defects.Through this synergistic mecha-nism,the deep and shallow energy level defects are effectively mitigated,resulting in improved device performance.As a result,the resulting treated inverted PSC exhibits an impressive power conversion ef-ficiency(PCE)of 24.72%.Notably,the PTA-treated PSCs exhibit remarkable stability,with 88.5%of the original PCE retained after undergoing heat aging at 85℃ for 1078 h,and 89.1%of the initial PCE main-tained following continuous exposure to light for 1100 h at the maximum power point.Synergistically suppressing multiple defects at the buried interface through the use of polyionic liquids is a promising way to improve the commercial viability of PSCs.
基金financially supported by the Natural Science Foundation of Guangdong Province(No.2024A1515010639)PolyU Postdoc Matching Fund Scheme(No.1-W327),PolyU Grant(No.1-CE0H)+3 种基金Shenzhen Science and Technology Program(No.ZDSYS20220606100406016)Shenzhen Key Laboratory of Photonics and Biophotonics(No.ZDSYS20210623092006020)National Key Laboratory of Green and Long-Life Road Engineering in Extreme Environment(Shenzhen)(No.868-000003010103)National Natural Science Foundation of China(No.52208272)。
文摘Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(TENGs)stand out as a prominent device capitalizing on the principles of triboelectrification and electrostatic induction to generate electricity or electrical signals.In efforts to augment the electrical output performance of TENGs and broaden their range of applications,researchers have endeavored to refine materials,surface morphology,and structural design.Among them,physical morphological modifications play a pivotal role in enhancing the electrical properties of TENGs by increasing the contact surface area,which can be achieved by building micro-/nano-structures on the surface or inside the friction material.In this review,we summarize the common morphologies of TENGs,categorize the morphologies into surface and internal structures,and elucidate their roles in enhancing the electric output performance of devices.Moreover,we systematically classify the methodologies employed for morphological preparation into physical and chemical approaches,thereby furnishing a comprehensive survey of the diverse techniques.Subsequently,typical applications of TENGs with special morphology divided by energy harvesting and self-powered sensors are presented.Finally,an overview of the challenges and future trajectories pertinent to TENGs is conducted.Through this endeavor,the aim of this article is to catalyze the evolution of further strategies for enhancing performance of TENGs.
基金supported by the National Key R&D Program of China(No.2023YFC3707201)the National Natural Science Foundation of China(No.52320105003)+2 种基金the Informatization Plan of Chinese Academy of Sciences(No.CASWX2023PY-0103)CAS-ANSO Co-funding Research Project(No.CAS-ANSO-CF-2024)the Fundamental Research Funds for the Central Universities(No.E3ET1803)。
文摘Air pollution,a critical environmental issue,necessitates urgent action.It originates from both human activities,like industrial emissions and vehicle pollution,and natural events such as sandstorms,leading to increased atmospheric pollutants such as sulfur dioxide(SO_(2)),nitrogen dioxide(NO_(2)),ammonia ion(NH_(4)^(+)),black carbon,ozone,and fine particulate matter(PM_(2.5)).Leveraging China's extensive air quality monitoring data,artificial intelligence(AI)was used in this study to enhance air quality prediction and management.The study aims to utilize the vast air monitoring data more effectively by developing advanced air quality assessment methods and AI models.An AI-based method presented in this study was applied to train extensive air quality data,enabling an intelligent air quality index(AQI)that swiftly and accurately reflects air quality status,to assess impacts on sensitive groups,and to predict future trends.This smart prediction and optimization(SPO)approach not only utilizes existing monitoring network data efficiently but also offers precise future air quality forecasts,providing valuable strategies for pollution prevention and air quality improvement.Data on various pollutants were collected from four regions in China between August 2021 and July 2022,using diverse modeling techniques and machine learning methodologies.The models achieved a high accuracy level of around 99%,indicating the significant portion of air quality that falls into the unhealthy category,especially impacting sensitive groups and reflecting the adverse atmospheric conditions in the studied regions.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2021YFA1400303)the National Natural Science Foundation of China (Grant No. 12227806)。
文摘We have investigated the magnetic, dielectric, pyroelectric, and thermal expansion properties of a layered perovskite metal–organic framework, [NH_(4)Cl]_(2)[Ni(HCOO)_(2)(NH_(3))_(2)]. The material undergoes three phase transitions including a canted antiferromagnetic transition at ~36 K, and two successive structural transitions around 100 K and 110 K, respectively. The temperature dependence of dielectric permittivity and pyroelectric current suggests that the structural transitions induce weak ferroelectricity along the c-axis and antiferroelectricity in the ab plane. A negative thermal expansion along the c-axis is observed between two structural phase transitions, which is ascribed to the abnormal shrinkage of interlayer hydrogen bonding length. Moreover, the ferroelectric/antiferroelectric phase transition temperature shifts towards a higher temperature under a magnetic field, suggesting certain magnetoelectric coupling in the paramagnetic phase. Our study suggests that the layered metal–organic frameworks provide a unique playground for exploring exotic physical properties such as multiferroicity and abnormal thermal expansion.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12274230)the Funding of Nanjing University of Science and Technology (Grant No. TSXK2022D005)。
文摘The attosecond extreme ultraviolet(XUV) pulse pump and femtosecond infrared(IR) pulse probe scheme is commonly used to study the dynamics and attosecond transient absorption(ATA) spectra of microscopic systems. In a recent report [Proc. Natl. Acad. Sci. USA 121 e2307836121(2024)], we showed that shaped XUV pulses with spectral minima can significantly alter the absorption line shape of helium's 2s2p doubly excited state within a few tens of attoseconds.However, it remains unclear if similar effects could be observed in a singly excited state. In this study, we use shaped XUV pulses to excite helium's 2p singly excited state and couple the 2p and 3d states with a delayed IR pulse. Comparing these results with those from Gaussian XUV pulses, we find that the ATA spectra for the shaped XUV pulses exhibit more pronounced changes with delay, while the changes for the Gaussian pulses are gradual. We also explain these differences through population changes and analytical models. Our findings show that shaped XUV pulses can regulate the dynamics and absorption spectra of a singly excited state.
基金funding support by the Changsha Natural Science Foundation(grant no.kq2208023)National Natural Scientific Foundation of China(grant no.12074113).
文摘Transition metal(oxy)hydroxides are potential oxygen evolution reaction(OER)electrocatalysts;however,simultaneously modulating multiple factors to enhance their performance is a grand challenge.Here,we report an incorporating heteroatom strategy via one-step hydrothermal approach to adjust more than one factor of Mn-doped NiFe(oxy)hydroxide(Mn-NiFeOOH/LDH)heterojunction.Mn doping regulates heterojunction morphology(reducing nanoparticles and becoming thinner and denser nanosheets),Ni/Fe ratio and valence states(Ni^(2+),Ni^(3+),and Ni^(3+Δ))of Ni ions.The former could effectively increase surface active sites,and the latter two reduce the content of Fe in the Mnx-NiFeOOH/LDH heterojunction,en-abling more Ni^(2+)convert to Ni^(3+/3+Δ)that have higher intrinsic OER activity.As a result,the first-rank Mn-NiFeOOH/LDH with ultra-low overpotential of 185 mV@20 mA cm^(-2) and 296 mV@500 mA cm^(-2),and the improved OER performance are outdo to those of commercial RuO_(2) catalyst for OER.Moreover,the Mn-NiFeOOH/LDH affords the earliest initial potential(1.392 V vs.RHE),corresponds to a recorded low overpotential(162 mV).Based on the density functional theory(DFT),Mn dopants can alter intermedi-ate adsorption energy and effectively decrease∗OOH’s energy barrier.This research exhibits a feasible strategy to design low cost electrocatalysts and provide new possibilities for future industrialization.
基金financially supported by the Innovation Team Cultivation Project of Yunnan Province(No.202005AE160016)the Key Research&Development Program of Yunnan Province(No.202103AA080017)Yunnan Ten Thousand Talents Plan Young&Elite Talents Project(No.YNWR-QNBJ2018-044)。
文摘The construction of intermetallic compounds(IMCs)connection layers with special compositions by adding small amounts of alloying elements has been proven to be an effective strategy for improving the reliability of electronic component interconnect.However,the synergistic effect mechanism of multi-component alloy compositions on the growth behavior of IMCs is not clear.Herein,we successfully prepared a new quaternary alloy solder with a composition of Sn-0.7Cu-0.175Pt-0.025Al(wt%)using the high-throughput screening(HTS)method.The results showed that it possesses excellent welding performance with an inhibition rate over 40%on the growth of IMCs layers.For Cu_(6)Sn_(5),the co-doping of Al and Pt not only greatly improves its thermodynamic stability,but also effectively suppresses the phase transition.Meanwhile,the co-doping of Al and Pt also significantly delays the generation time of Kirkendall defects.The substitution sites of Al and Pt in Cu_(6)Sn_(5)have been explored using atomic resolution imaging and advanced data informatics,indicating that Al and Pt preferentially substitute Sn and Cu atoms,respectively,to generate(Cu,Pt)_(6)(Sn,Al)_(5).A one-dimensional(1D)kinetic model of the IMCs layer growth at the Sn solder/Cu substrate interface was derived and validated,and the results showed that the error of the derived mathematical model is less than 5%.Finally,the synergistic mechanism of Al and Pt co-doping on the growth rate of Cu_(6)Sn_(5)was further elucidated.This work provides a feasible route for the design and development of multi-component alloy solders.
文摘The careful observation and evaluation of the squamocolumnar junction(SCJ)are essential requirements in colposcopy procedures.While traditional colposcopes with visible light offer high resolution and sensitivity,the presence of glare patterns on the cervix limits the visualization of deeper tissue features.Cross-polarization imaging,on the other hand,overcomes this limitation by effectively removing glare and providing greater optical penetration depth to noninvasively examine subsurface tissue structures.In this study,we present the potential of polarized light in enhancing diagnostics through cross-polarization imaging for the identification and contrast enhancement of squamous and columnar epithelium(CE)in cases of cervical ectropion.Our results demonstrate that polarized light colposcopy offers valuable diagnostic information that complements traditional colposcopy.By effectively reducing glare and improving visibility during cervical examinations,polarized light colposcopy proves to be a useful tool.Furthermore,we introduce a novel method that practically enhances the contrast ratio(CR)between columnar and squamous epithelium(SE)in colposcopic images.This method significantly increases the contrast between these tissue types,facilitating clearer differentiation and improving diagnostic accuracy.Notably,the combination of the cross-polarization imaging technique with our proposed algorithm enables the clear observation of the SCJ boundary.These findings emphasize the potential of our approach in enhancing the accuracy and effectiveness of polarized colposcopy for evaluating cervical tissue.
基金supported by Matching Fund from Thammasat University Research Fund,Thammasat University,under Contract No.MF2/2567the ETS scholarship awarded by Sirindhorn International Institute of Technology,Thammasat University。
文摘Transition metal dichalcogenides(TMDs)have emerged as promising electrocatalysts for various electrocatalytic processes.Molybdenum disulfide has been widely used,but a single electrocatalyst can hardly be applied to all reactions,making it essential to understand the electrochemistry of selected TMDs.Tungsten diselenide(WSe_(2))is reactive in gas evolution processes,similar to molybdenum,yet has received limited attention.This work explores how different exfoliation powers affect WSe_(2)structural configurations and their impact on catalytic performance in hydrogen evolution,oxygen evolution,and capacitive behaviour.The study investigates the structural properties of WSe_(2)nanosheets in both liquid(dispersion)and solid(electrode)phases.Low exfoliation power(90.4 W)contributes to well-defined WSe_(2),while higher power(814 W)leads to an increased number of selenium vacancies.These modifications influence key properties such as thickness,band gaps(1.518 to 1.578 eV),exfoliation yield(0.27 to 0.12 mg mL^(-1)),and oxide content(44.3%to 53.9%),resulting in distinct electrochemical behaviours in different electrolytes.WSe_(2)nanosheets exfoliated at higher power exhibit reduced activity in the hydrogen evolution reaction(HER)due to the loss of W–Se bonds and the formation of an amorphous structure,but they show enhanced oxygen evolution reaction(OER)performance,particularly in alkaline media.Additionally,a higher concentration of selenium vacancies improves capacitive performance in acidic conditions due to proton contributions but are less favourable in neutral and basic electrolytes.This study highlights the importance of exfoliation power in tuning the structural properties of WSe_(2)for specific electrochemical applications,advancing the understanding of its synthesis and performance.
基金supported by the National Nature Science Foundation(Nos.52372125 and 52333009)the National Key Research and Development Project(Nos.2020YFC1521900 and 2020YFC1521904)+4 种基金the Shaanxi Provincial Science Foundation(No.2021GXLH-01-11)the Yulin Project(No.2022-19-11)the Fundamental Research Funds for the Central Universities(No.D5000230071)the 111 Program(No.B08040)of MOE of Chinasponsored by Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2024063).
文摘Ferroelectric materials find extensive applications in brake systems due to their capability to convert electrical energy into mechanical energy.Recent research has focused on lead-free materials for their environmentally friendly characteristics.However,they exhibit several challenges such as significant negative strain,limited strain values,and large driving field.In this work,novel preparation techniques(electrospinning)were utilized for BaTiO_(3)to introduce oxygen vacancies and barium defects,facilitating the creation of oriented defect dipoles coupled with an intrinsic electric field(Ei)after poling and aging.Due to the existence of Ei,two minimum points in the strain hysteresis loop were shifted to the same quadrant in the Strain-Electric field space.Thus,when applying an electric field along the Ei direction,negative strain is eliminated.Additionally,the actual electric field is the sum of the applied electric field and Ei,thereby reducing the required driving field of the piezoelectric.The stretching of defect dipoles under the electric field further amplified the total strain.Through the proposed mechanisms,this work achieved a substantial unipolar electrostrain of 1.04%under a relatively low electric field(30 kV/cm)in BaTiO_(3).This work successfully addressed the challenges of high-driving electric fields,limited strain values,and negative strain,providing a comprehensive approach for improving field-induced strain performance through point defect engineering in ferroelectric materials.
基金the National Natural Science Foundation of China(NSFC,Grant Nos.61975213,61475164,51901234,and 61205194)National Key R&D Program of China(Grant Nos.2017YFB1104300and 2016YFA0200500)+2 种基金International Partnership Program of Chinese Academy of Sciences(GJHZ2021130)Cooperative R&D Projects between Austria,FFG and China,CAS(GJHZ1720)supported by JSPS Bilateral Program Number JPJSBP120217203。
文摘Chitosan(CS)-based nanocomposites have been studied in various fields,requiring a more facile and efficient technique to fabricate nanoparticles with customized structures.In this study,Ag@methacrylamide CS/poly(ethylene glycol)diacrylate(Ag@MP)micropatterns are successfully fabricated by femtosecond laser maskless optical projection lithography(Fs-MOPL)for the first time.The formation mechanism of core-shell nanomaterial is demonstrated by the local surface plasmon resonances and the nucleation and growth theory.Amino and hydroxyl groups greatly affect the number of Ag@MP nanocomposites,which is further verified by replacing MCS with methacrylated bovine serum albumin and hyaluronic acid methacryloyl,respectively.Besides,the performance of the surface-enhanced Raman scattering,cytotoxicity,cell proliferation,and antibacterial was investigated on Ag@MP micropatterns.Therefore,the proposed protocol to prepare hydrogel core-shell micropattern by the home-built Fs-MOPL technique is prospective for potential applications in the biomedical and biotechnological fields,such as biosensors,cell imaging,and antimicrobial.
基金supported by the Australian Research Council via Discovery Projects(Nos.DP200103315,DP200103332 and DP230100685)Linkage Projects(No.LP220200920)+1 种基金support from the IONTOF M6 ToF-SIMS(funded by ARC LIEF,LE190100053)the Kratos Axis Ultra XPS(ARC LIEF,LE120100026)。
文摘Ni-rich LiNi0.8Mn0.1Co0.1O2(NCM)cathodes in layered oxide cathodes are attractive for high-energy lithium-ion batteries but suffer from rapid capacity fade and thermal instability at high charge voltages.In this study,we propose an entropy-assisted multi-element doping strategy to mitigate these issues.Specifically,two routes are designed and compared:bulk-like localized high-entropy doping(BHE-NCM)and surface-distributed high-entropy-zone doping(SHE-NCM).The surface entropy-doped NCM cathode delivers enhanced electrochemical performance,including higher capacity retention under 4.5 V cycling and superior rate capability,compared to both bulk-like and pristine counterparts.Comprehensive material characterization reveals that surface-localized doping stabilizes the layered structure with reduced microcrack formation and creates a uniform dopant-rich surface region with improved thermal and electrochemical stability.Overall,entropy-assisted doping at the near surface zone effectively alleviates structural degradation and interface reactions in Ni-rich NCM,enabling improved cycling performance at high voltage.This work highlights the significance of surface entropy engineering as a promising strategy for designing high-voltage cathodes with improved safety and longevity.
