Purpose: To develop and test a mission-oriented and multi-dimensional benchmarking method for a small scale university aiming for internationally first-class basic research.Design/methodology/approach: An individualiz...Purpose: To develop and test a mission-oriented and multi-dimensional benchmarking method for a small scale university aiming for internationally first-class basic research.Design/methodology/approach: An individualized evidence-based assessment scheme was employed to benchmark ShanghaiTech University against selected top research institutions,focusing on research impact and competitiveness at the institutional and disciplinary levels.Topic maps opposing ShanghaiTech and corresponding top institutions were produced for the main research disciplines of ShanghaiTech. This provides opportunities for further exploration of strengths and weakness. Findings: This study establishes a preliminary framework for assessing the mission of the university. It further provides assessment principles, assessment questions, and indicators.Analytical methods and data sources were tested and proved to be applicable and efficient.Research limitations: To better fit the selective research focuses of this university, its schema of research disciplines needs to be re-organized and benchmarking targets should include disciplinary top institutions and not necessarily those universities leading overall rankings.Current reliance on research articles and certain databases may neglect important research output types.Practical implications: This study provides a working framework and practical methods for mission-oriented, individual, and multi-dimensional benchmarking that ShanghaiTech decided to use for periodical assessments. It also offers a working reference for other institutions to adapt. Further needs are identified so that ShanghaiTech can tackle them for future benchmarking.Originality/value: This is an effort to develop a mission-oriented, individually designed,systematically structured, and multi-dimensional assessment methodology which differs from often used composite indices.展开更多
With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite h...With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity.The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene nanoplates.The unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric synergy.Therefore,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 mm.Besides,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.展开更多
The traditional von Neumann architecture faces inherent limitations due to the separation of memory and computa-tion,leading to high energy consumption,significant latency,and reduced operational efficiency.Neuromorph...The traditional von Neumann architecture faces inherent limitations due to the separation of memory and computa-tion,leading to high energy consumption,significant latency,and reduced operational efficiency.Neuromorphic computing,inspired by the architecture of the human brain,offers a promising alternative by integrating memory and computational func-tions,enabling parallel,high-speed,and energy-efficient information processing.Among various neuromorphic technologies,ion-modulated optoelectronic devices have garnered attention due to their excellent ionic tunability and the availability of multi-dimensional control strategies.This review provides a comprehensive overview of recent progress in ion-modulation optoelec-tronic neuromorphic devices.It elucidates the key mechanisms underlying ionic modulation of light fields,including ion migra-tion dynamics and capture and release of charge through ions.Furthermore,the synthesis of active materials and the proper-ties of these devices are analyzed in detail.The review also highlights the application of ion-modulation optoelectronic devices in artificial vision systems,neuromorphic computing,and other bionic fields.Finally,the existing challenges and future direc-tions for the development of optoelectronic neuromorphic devices are discussed,providing critical insights for advancing this promising field.展开更多
This study investigates photonuclear reaction(γ,n)cross-sections using Bayesian neural network(BNN)analysis.After determining the optimal network architecture,which features two hidden layers,each with 50 hidden node...This study investigates photonuclear reaction(γ,n)cross-sections using Bayesian neural network(BNN)analysis.After determining the optimal network architecture,which features two hidden layers,each with 50 hidden nodes,training was conducted for 30,000 iterations to ensure comprehensive data capture.By analyzing the distribution of absolute errors positively correlated with the cross-section for the isotope 159Tb,as well as the relative errors unrelated to the cross-section,we confirmed that the network effectively captured the data features without overfitting.Comparison with the TENDL-2021 Database demonstrated the BNN's reliability in fitting photonuclear cross-sections with lower average errors.The predictions for nuclei with single and double giant dipole resonance peak cross-sections,the accurate determination of the photoneutron reaction threshold in the low-energy region,and the precise description of trends in the high-energy cross-sections further demonstrate the network's generalization ability on the validation set.This can be attributed to the consistency of the training data.By using consistent training sets from different laboratories,Bayesian neural networks can predict nearby unknown cross-sections based on existing laboratory data,thereby estimating the potential differences between other laboratories'existing data and their own measurement results.Experimental measurements of photonuclear reactions on the newly constructed SLEGS beamline will contribute to clarifying the differences in cross-sections within the existing data.展开更多
The catalytic enantioselective electrophilic amination reaction has emerged as a highly efficient method for synthesizing diverse nitrogen-containing chiral molecules,with the development of various asymmetric catalys...The catalytic enantioselective electrophilic amination reaction has emerged as a highly efficient method for synthesizing diverse nitrogen-containing chiral molecules,with the development of various asymmetric catalysis systems.Chiral phosphoric acids(CPA)have been widely acknowledged as versatile chiral organocatalysts since it was first discovered in 2004,finding application in catalyzing diverse asymmetric reactions.A comprehensive overview of recent advances in CPA-catalyzed asymmetric electrophilic amination reactions using different N-electrophilic reagents,including azo reagents,aryldiazonium salts,and imine derivatives,is presented.Furthermore,insights into future developments in this field are offered.展开更多
The research on high-performance electromagnetic wave absorption materials with high-temperature and oxidative stability in extreme environments is gaining popularity.Herein,the lightweight silicon carbide nanowires(S...The research on high-performance electromagnetic wave absorption materials with high-temperature and oxidative stability in extreme environments is gaining popularity.Herein,the lightweight silicon carbide nanowires(SiC_(nws))/SiC composites are fabricated with in-situ SiC interface on one-dimensional oriented SiC_(nws)skeleton,which collaborative configuration by 3D printing and freeze casting assembly.The con-structed porous structure optimizes the impedance matching degree and scattering intensity,the maximum effective absorption bandwidth(EAB_(max))of 5.9 GHz and the minimum reflection loss(RL_(min))of−41.4 dB can be realized.Considering the inherent oxidation resistance of SiC,the composites present well-maintained absorption performance at 600℃.Even at 1100℃,the EAB_(max)of 4.9 GHz and RLmin of−30.4 dB also demonstrate the high-temperature absorption stability of the composites,indicating exceptional wave absorption properties and thermal stability.The slight attenuation can be attributed to the decrease in impedance matching capability accompanying the elevated dielectric constant.This work clarifies the impact of structure and component synergy on wave absorption behavior,and offers a novel approach to producing high-performance and high-temperature resistance ceramic-based electromagnetic wave absorption materials suitable for extreme environments.展开更多
By using a newly developed 4-hydroxy picolinohydrazide as the ligand,Cu-catalyzed coupling of(hetero)aryl chlorides with sodium aryl sulfonates proceeded smoothly at 130℃to give a series of biarylsulfones in 53%~96%y...By using a newly developed 4-hydroxy picolinohydrazide as the ligand,Cu-catalyzed coupling of(hetero)aryl chlorides with sodium aryl sulfonates proceeded smoothly at 130℃to give a series of biarylsulfones in 53%~96%yields.This represents the first metal-catalyzed coupling reaction of(hetero)aryl chlorides with sodium aryl sulfonates.Aryl and heteroaryl chlorides bearing either electron-donating or electron-withdrawing groups were applicable for this coupling reaction.展开更多
CeO_(2) based semiconductor are widely used in solar-driven photothermal catalytic dry reforming of methane(DRM)reaction,but still suffer from low activity and low light utilization efficiency.This study developed gra...CeO_(2) based semiconductor are widely used in solar-driven photothermal catalytic dry reforming of methane(DRM)reaction,but still suffer from low activity and low light utilization efficiency.This study developed graphite-CeO_(2) interfaces to enhance solar-driven photothermal catalytic DRM.Compared with carbon nanotubes-modified CeO_(2)(CeO_(2)-CNT),graphite-modified CeO_(2)(CeO_(2)-GRA)constructed graphite-CeO_(2) interfaces with distortion in CeO_(2),leading to the formation abundant oxygen vacancies.These graphite-CeO_(2) interfaces with oxygen vacancies enhanced optical absorption and promoted the generation and separation of photogenerated carriers.The high endothermic capacity of graphite elevated the catalyst surface temperature from 592.1−691.3℃,boosting light-to-thermal conversion.The synergy between photogenerated carriers and localized heat enabled Ni/CeO_(2)-GRA to achieve a CO production rate of 9985.6 mmol/(g·h)(vs 7192.4 mmol/(g·h)for Ni/CeO_(2))and a light-to-fuel efficiency of 21.8%(vs 13.8%for Ni/CeO_(2)).This work provides insights for designing graphite-semiconductor interfaces to advance photothermal catalytic efficiency.展开更多
We report the epitaxial growth of high-quality Al_(0.8)Ga_(0.2)Sb/InAs/Al_(0.8)Ga_(0.2)Sb quantum well films characterized by high carrier mobility and strong spin-orbit coupling.By appropriately optimizing the Al-to-...We report the epitaxial growth of high-quality Al_(0.8)Ga_(0.2)Sb/InAs/Al_(0.8)Ga_(0.2)Sb quantum well films characterized by high carrier mobility and strong spin-orbit coupling.By appropriately optimizing the Al-to-Ga ratio in the AlGaSb barrier layer,the quantum confinement of the heterostructure is significantly enhanced.Alongside a giant magnetoresistance ratio of 3.65×10^(5)%,the two-carrier transport model from Hall measurements reveals an ultra-high electron mobility of 7.18×10^(5)cm^(2)·V^(-1)·s^(-1)at low temperatures.Meanwhile,pronounced Shubnikov-de Haas(SdH)quantum oscillations persist up to 30 K,and their single-frequency feature indicates a well-defined Fermi surface without subband mixing in the two-dimensional electron gas channel.Moreover,the large effective g-factor and tilted-field-induced orbital effect lead to the observation of split SdH peaks at large magnetic fields.Our results validate that AlGaSb/InAs quantum well heterostructures are suitable candidates for constructing energy-efficient topological spintronic devices.展开更多
Currently,in STEM environments,female employees are often recognized as minorities due to their positioning or occupancy rate,which may lead to experiences of“imposter syndrome”.This study applies frameworks of mixe...Currently,in STEM environments,female employees are often recognized as minorities due to their positioning or occupancy rate,which may lead to experiences of“imposter syndrome”.This study applies frameworks of mixed-gender discourse,such as limited involvement in activity as an agent,markedness,and gender-differentiated roles,to clarify how women in STEM position themselves or are positioned by the society.Using corpus linguistics and content analysis,it is clarified that female researchers are usually linguistically marked or tend to distinguish themselves as non-experts.Thus,their portrayal within a misogynistic society may considerably interact with how female researchers represent themselves.展开更多
Oxysulfide semiconductors are promising photocatalysts for visible light-driven water splitting.For a widely studied narrow-bandgap Sm_(2)Ti_(2)O_(5)S_(2)(STOS),limited bulk charge separation and slow surface reaction...Oxysulfide semiconductors are promising photocatalysts for visible light-driven water splitting.For a widely studied narrow-bandgap Sm_(2)Ti_(2)O_(5)S_(2)(STOS),limited bulk charge separation and slow surface reaction heavily restrict its photocatalytic performance.Here,well-crystallized STOS oxysulfide nanosheets,synthesized by a flux-assisted solid-state reaction,were proved to show prominent facet-oriented charge transport property,in which photogenerated electrons migrated to{101}planes and holes to{001}planes of each particle.Hydrogen evolution cocatalysts were therefore precisely positioned on the electron-rich facets to boost the water reduction reaction.In particular,in-situ formation of a Ptshell@Ircore core-shell structure on the electron-rich{101}facets and an IrO_(2) on the hole-accumulated{001}facets greatly assisted the sacrificial photocatalytic H_(2) production over STOS,resulting in an apparent quantum yield as high as 35.9%at 420 nm.By using the highly-active STOS as H_(2) evolution photocatalyst,a Mo:BiVO_(4) as oxygen evolution photocatalyst,and a[Co(bpy)_(3)]^(2+/3+)as redox shuttle,a Z-Scheme overall water splitting system was constructed to achieve a solar-to-hydrogen conversion efficiency of 0.175%.This work not only elucidates the facet-dependent charge transfer mechanism on STOS but also proposes an ideal strategy for enhancing its photocatalytic performance.展开更多
Ultrabright femtosecond X-ray pulses generated by X-ray free-electron lasers(XFELs)enable the high-resolution determination of nanoparticle structures without crystallization or freezing.As each particle that interact...Ultrabright femtosecond X-ray pulses generated by X-ray free-electron lasers(XFELs)enable the high-resolution determination of nanoparticle structures without crystallization or freezing.As each particle that interacts with the pulse is destroyed,an aerodynamic lens(ADL)is used to update the particles by focusing them into a narrow beam in real time.Current single-particle imaging(SPI)experiments are limited by an insufficient number of diffraction patterns;therefore,optimized ADLs are required to improve the hit rate and signal-to-noise ratio,particularly for small particles.Herein,an efficient and simple method for designing ADLs and a new ADL specifically designed for SPI using this method are presented.A new method is proposed based on the functional relationship between a key parameter and its influencing parameters in the ADL,which is established through theoretical analysis and numerical simulations.A detailed design process for the new ADL is also introduced.Both simulations and experiments are performed to characterize the behavior of the particles in the ADL.The results show that particles with diameters ranging from 30 to 500 nm can be effectively focused into a narrow beam.In particular,particles smaller than 100 nm exhibit better performance at lower flow rates than the injector currently used in SPI.The new ADL increases the beam density and reduces the gas background noise.This new method facilitates the design of ADLs for SPI and has potential applications in other fields that utilize focused aerosol beams.展开更多
Transcranial focused ultrasound(tFUS)is an emerging modality with strong potential for non-invasively treating brain disorders.However,the inhomogeneity and complex structure of the skull induce substantial phase aber...Transcranial focused ultrasound(tFUS)is an emerging modality with strong potential for non-invasively treating brain disorders.However,the inhomogeneity and complex structure of the skull induce substantial phase aberrations and pressure attenuation;these can distort and shift the acoustic focus,thus hindering the efficiency of tFUS therapy.To achieve effective treatments,phased array transducers combined with aberration correction algorithms are commonly implemented.The present report aims to provide a comprehensive review of the current methods used for tFUS phase aberration correction.We first searched the PubMed and Web of Science databases for studies on phase aberration correction algorithms,identifying 54 articles for review.Relevant information,including the principles of algorithms and refocusing performances,were then extracted from the selected articles.The phase correction algorithms involved two main steps:acoustic field estimation and transmitted pulse adjustment.Our review identified key benchmarks for evaluating the effectiveness of these algorithms,each of which was used in at least three studies.These benchmarks included pressure and intensity,positioning error,focal region size,peak sidelobe ratio,and computational efficiency.Algorithm performances varied under different benchmarks,thus highlighting the importance of application-specific algorithm selection for achieving optimal tFUS therapy outcomes.The present review provides a thorough overview and comparison of various phase correction algorithms,and may offer valuable guidance to tFUS researchers when selecting appropriate phase correction algorithms for specific applications.展开更多
In the pursuit of carbon neutrality,hydrogen(H_(2))is often hailed as the ideal fuel for fuel cell vehicles(FCVs)due to its zero-emission nature and high gravimetric energy density.However,its low volumetric density n...In the pursuit of carbon neutrality,hydrogen(H_(2))is often hailed as the ideal fuel for fuel cell vehicles(FCVs)due to its zero-emission nature and high gravimetric energy density.However,its low volumetric density necessitates high-pressure on-board storage(up to 700 bar),which are costly and pose significant safety risks.To cope with these challenges,the U.S.Department of energy(DOE)has set ambitious targets for hydrogen storage systems,aiming for a gravimetric capacity of 6.5 wt%with a volumetric capacity of 50 g L^(-1).Porous crystals,exemplified by metal-organic frameworks(MOFs)[1,2],covalent organic frameworks(COFs),and hydrogen-bonded organic frameworks(HOFs)[3],have shown promise for hydrogen storage at 77 K with delivery at 160 K under significantly lower pressures(≤100 bar).展开更多
This paper introduces a hybrid fluid-kinetic code,SHYPIC(ShanghaiTech HYbrid PIC code),developed as a baseline framework for simulating plasma dynamics relevant to plasma-jetdriven magneto-inertial fusion(PJMIF).The c...This paper introduces a hybrid fluid-kinetic code,SHYPIC(ShanghaiTech HYbrid PIC code),developed as a baseline framework for simulating plasma dynamics relevant to plasma-jetdriven magneto-inertial fusion(PJMIF).The code integrates a fluid description for electrons and a particle-in-cell(PIC)description for ions,providing computational efficiency and enabling larger-scale simulations.It incorporates ion kinetic effects,allowing accurate simulation of microscale non-equilibrium phenomena.In this initial version,the SHYPIC code is presented along with a series of benchmark tests,including quiet plasma evolution,dispersion relation verification,and the excitation and propagation of externally driven plasma waves.This version does not yet incorporate collisional effects or non-ideal terms(e.g.,resistivity,viscosity,and hyperviscosity)in the electron fluid,which will be included in future developments.The present work lays the foundation for further improvements required for fully simulating the complex dynamics of PJMIF.展开更多
Oxidative coupling of methane(OCM)is a catalytic partial oxidation process that directly converts methane into C_(2) products.For this high temperature reaction,understanding the radical behavior through experimental ...Oxidative coupling of methane(OCM)is a catalytic partial oxidation process that directly converts methane into C_(2) products.For this high temperature reaction,understanding the radical behavior through experimental investigation is important in correlating the catalytic activity and the products.In this work,a spatial resolution online mass spectrometry(MS)system was developed and applied to a Mn-Na_(2)WO_(4)/SiO_(2) catalyzed OCM system.In addition to the residue gas analysis,the system obtained the distribution information of the reactants and products in the reactor.At various setting temperatures,all species online MS signals were collected at different positions,mapping the reaction activity covering parameters including temperature,time and space.The distribution behavior of the catalytic activity,selectivity,and apparent activation energy were kinetically analyzed.Selectivity and additional carbon balance analysis strongly supported the radical coupling model of OCM and indicated that after the catalytic bed layer,there is a significant length in the reactor(>2 mm)filled with radicals.Based on the result,a designed new method by tuning the temperature field in the reactor was found effectively to improve the catalytic activity,especially the C_(2) yield from 702 to 773℃.展开更多
We present a hybrid smoothed particle magnetohydrodynamics(SPMHD)code integrating smoothed particle hydrodynamics(SPH)and finite element methods(FEM)to simulate coupled fluid-electromagnetic phenomena.The framework em...We present a hybrid smoothed particle magnetohydrodynamics(SPMHD)code integrating smoothed particle hydrodynamics(SPH)and finite element methods(FEM)to simulate coupled fluid-electromagnetic phenomena.The framework employs SPH for fluid dynamics,addressing large deformations,shocks,and plasma behavior,while FEM resolves electromagnetic fields via Maxwell's equations for magnetic vector and electric scalar potentials,ensuring divergence-free conditions and global current density calculations in conductive region.Operator splitting method couples these modules,enabling real-time integration of magnetic,electric,thermal,and fluid fields.Benchmark tests validate the code against analytical solutions and existing models,including blow-by instability simulations that demonstrate the method's accuracy in capturing fluid-magnetic interactions.Designed for 3D applications,SPMHD offers robust scalability across multiprocessor architectures,establishing it as a versatile tool for plasma physics research.展开更多
Fe-based catalysts are widely used for CO_(2)hydrogenation to light olefins(C_(2–4)=);however,precise regulation of active phases and the balance between intermediate reactions remain significant challenges.Herein,we...Fe-based catalysts are widely used for CO_(2)hydrogenation to light olefins(C_(2–4)=);however,precise regulation of active phases and the balance between intermediate reactions remain significant challenges.Herein,we find that the addition of moderate amounts of Ti forms a strong interaction with Fe compositions,modulating the Fe_(3)O_(4)and Fe_(5)C_(2)contents.Enhanced interaction leads to an increased Fe_(5)C_(2)/Fe_(3)O_(4)ratio,which in turn enhances the adsorption of reactants and intermediates,promoting CO hydrogenation to unsaturated alkyl groups and facilitating C–C coupling.Furthermore,the strong Fe-Ti interaction induces the preferential growth of Fe_(5)C_(2)into prismatic structures that expose the(020),(–112),and(311)facets,forming compact active interfacial sites with Fe_(3)O_(4)nanoparticles.These facet and interfacial effects significantly promote the synergistic coupling of the reverse water gas shift and Fischer-Tropsch reactions.The optimized 3K/FeTi catalyst with the highest Fe_(5)C_(2)/Fe_(3)O_(4)ratio of 3.6 achieves a 52.2%CO_(2)conversion rate,with 44.5%selectivity for C2–4=and 9.5%for CO,and the highest space-time yield of 412.0 mg gcat^(–1)h^(–1)for C_(2–4)=.展开更多
Fe-based superconductors represent a fascinating class of materials,extensively studied for their complex interplay of superconductivity,magnetism,spin density waves,and nematicity,along with the interactions among th...Fe-based superconductors represent a fascinating class of materials,extensively studied for their complex interplay of superconductivity,magnetism,spin density waves,and nematicity,along with the interactions among these orders.An intriguing yet unexplained phenomenon observed in Fe-based superconductors is the emergence of superconductivity below 25K in the non-superconducting parent compound SrFe_(2)As_(2)following exposure to water at its surface.In this study,we employed in situ angle-resolved photoemission spectroscopy and low-energy electron diffraction to meticulously examine the electronic structure evolution of SrFe_(2)As_(2)upon in situ water dosing.Our findings indicate that water dosing markedly attenuates the spin density wave phase and surface Sr reconstruction while preserving the nematic order in SrFe_(2)As_(2).Furthermore,we detected an enhancement in the spectral weight of bands near the Fermi level.Our observations highlight the critical role of the intricate interplay among various orders induced by water dosing,which effectively modifies the band structure and favors the emergence of superconductivity in SrFe_(2)As_(2).展开更多
文摘Purpose: To develop and test a mission-oriented and multi-dimensional benchmarking method for a small scale university aiming for internationally first-class basic research.Design/methodology/approach: An individualized evidence-based assessment scheme was employed to benchmark ShanghaiTech University against selected top research institutions,focusing on research impact and competitiveness at the institutional and disciplinary levels.Topic maps opposing ShanghaiTech and corresponding top institutions were produced for the main research disciplines of ShanghaiTech. This provides opportunities for further exploration of strengths and weakness. Findings: This study establishes a preliminary framework for assessing the mission of the university. It further provides assessment principles, assessment questions, and indicators.Analytical methods and data sources were tested and proved to be applicable and efficient.Research limitations: To better fit the selective research focuses of this university, its schema of research disciplines needs to be re-organized and benchmarking targets should include disciplinary top institutions and not necessarily those universities leading overall rankings.Current reliance on research articles and certain databases may neglect important research output types.Practical implications: This study provides a working framework and practical methods for mission-oriented, individual, and multi-dimensional benchmarking that ShanghaiTech decided to use for periodical assessments. It also offers a working reference for other institutions to adapt. Further needs are identified so that ShanghaiTech can tackle them for future benchmarking.Originality/value: This is an effort to develop a mission-oriented, individually designed,systematically structured, and multi-dimensional assessment methodology which differs from often used composite indices.
基金sponsored by National Natural Science Foundation of China(No.52302121,No.52203386)Shanghai Sailing Program(No.23YF1454700)+1 种基金Shanghai Natural Science Foundation(No.23ZR1472700)Shanghai Post-doctoral Excellent Program(No.2022664).
文摘With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity.The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene nanoplates.The unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric synergy.Therefore,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 mm.Besides,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.
基金supported by National Natural Science Foundation of China(62174164,U23A20568,and U22A2075)National Key Research and Development Project(2021YFA1202600)+2 种基金Talent Plan of Shanghai Branch,Chinese Academy of Sciences(CASSHB-QNPD-2023-022)Ningbo Technology Project(2022A-007-C)Ningbo Key Research and Development Project(2023Z021).
文摘The traditional von Neumann architecture faces inherent limitations due to the separation of memory and computa-tion,leading to high energy consumption,significant latency,and reduced operational efficiency.Neuromorphic computing,inspired by the architecture of the human brain,offers a promising alternative by integrating memory and computational func-tions,enabling parallel,high-speed,and energy-efficient information processing.Among various neuromorphic technologies,ion-modulated optoelectronic devices have garnered attention due to their excellent ionic tunability and the availability of multi-dimensional control strategies.This review provides a comprehensive overview of recent progress in ion-modulation optoelec-tronic neuromorphic devices.It elucidates the key mechanisms underlying ionic modulation of light fields,including ion migra-tion dynamics and capture and release of charge through ions.Furthermore,the synthesis of active materials and the proper-ties of these devices are analyzed in detail.The review also highlights the application of ion-modulation optoelectronic devices in artificial vision systems,neuromorphic computing,and other bionic fields.Finally,the existing challenges and future direc-tions for the development of optoelectronic neuromorphic devices are discussed,providing critical insights for advancing this promising field.
基金supported by National key research and development program(No.2022YFA1602404)the National Natural Science Foundation of China(Nos.12388102,12275338,12005280)the Key Laboratory of Nuclear Data foundation(No.JCKY2022201C152)。
文摘This study investigates photonuclear reaction(γ,n)cross-sections using Bayesian neural network(BNN)analysis.After determining the optimal network architecture,which features two hidden layers,each with 50 hidden nodes,training was conducted for 30,000 iterations to ensure comprehensive data capture.By analyzing the distribution of absolute errors positively correlated with the cross-section for the isotope 159Tb,as well as the relative errors unrelated to the cross-section,we confirmed that the network effectively captured the data features without overfitting.Comparison with the TENDL-2021 Database demonstrated the BNN's reliability in fitting photonuclear cross-sections with lower average errors.The predictions for nuclei with single and double giant dipole resonance peak cross-sections,the accurate determination of the photoneutron reaction threshold in the low-energy region,and the precise description of trends in the high-energy cross-sections further demonstrate the network's generalization ability on the validation set.This can be attributed to the consistency of the training data.By using consistent training sets from different laboratories,Bayesian neural networks can predict nearby unknown cross-sections based on existing laboratory data,thereby estimating the potential differences between other laboratories'existing data and their own measurement results.Experimental measurements of photonuclear reactions on the newly constructed SLEGS beamline will contribute to clarifying the differences in cross-sections within the existing data.
文摘The catalytic enantioselective electrophilic amination reaction has emerged as a highly efficient method for synthesizing diverse nitrogen-containing chiral molecules,with the development of various asymmetric catalysis systems.Chiral phosphoric acids(CPA)have been widely acknowledged as versatile chiral organocatalysts since it was first discovered in 2004,finding application in catalyzing diverse asymmetric reactions.A comprehensive overview of recent advances in CPA-catalyzed asymmetric electrophilic amination reactions using different N-electrophilic reagents,including azo reagents,aryldiazonium salts,and imine derivatives,is presented.Furthermore,insights into future developments in this field are offered.
基金supported by the National Key R&D Program of China(No.2022YFB3707700)National Natural Science Foundation of China(No.52302121)+3 种基金Shanghai Sailing Program(No.23YF1454700)Shanghai Natural Science Foundation(No.23ZR1472700)Shanghai Post-doctoral Excellent Program(No.2022664)Shanghai Science and Technology Innovation Action Plan(No.21511104800).
文摘The research on high-performance electromagnetic wave absorption materials with high-temperature and oxidative stability in extreme environments is gaining popularity.Herein,the lightweight silicon carbide nanowires(SiC_(nws))/SiC composites are fabricated with in-situ SiC interface on one-dimensional oriented SiC_(nws)skeleton,which collaborative configuration by 3D printing and freeze casting assembly.The con-structed porous structure optimizes the impedance matching degree and scattering intensity,the maximum effective absorption bandwidth(EAB_(max))of 5.9 GHz and the minimum reflection loss(RL_(min))of−41.4 dB can be realized.Considering the inherent oxidation resistance of SiC,the composites present well-maintained absorption performance at 600℃.Even at 1100℃,the EAB_(max)of 4.9 GHz and RLmin of−30.4 dB also demonstrate the high-temperature absorption stability of the composites,indicating exceptional wave absorption properties and thermal stability.The slight attenuation can be attributed to the decrease in impedance matching capability accompanying the elevated dielectric constant.This work clarifies the impact of structure and component synergy on wave absorption behavior,and offers a novel approach to producing high-performance and high-temperature resistance ceramic-based electromagnetic wave absorption materials suitable for extreme environments.
文摘By using a newly developed 4-hydroxy picolinohydrazide as the ligand,Cu-catalyzed coupling of(hetero)aryl chlorides with sodium aryl sulfonates proceeded smoothly at 130℃to give a series of biarylsulfones in 53%~96%yields.This represents the first metal-catalyzed coupling reaction of(hetero)aryl chlorides with sodium aryl sulfonates.Aryl and heteroaryl chlorides bearing either electron-donating or electron-withdrawing groups were applicable for this coupling reaction.
文摘CeO_(2) based semiconductor are widely used in solar-driven photothermal catalytic dry reforming of methane(DRM)reaction,but still suffer from low activity and low light utilization efficiency.This study developed graphite-CeO_(2) interfaces to enhance solar-driven photothermal catalytic DRM.Compared with carbon nanotubes-modified CeO_(2)(CeO_(2)-CNT),graphite-modified CeO_(2)(CeO_(2)-GRA)constructed graphite-CeO_(2) interfaces with distortion in CeO_(2),leading to the formation abundant oxygen vacancies.These graphite-CeO_(2) interfaces with oxygen vacancies enhanced optical absorption and promoted the generation and separation of photogenerated carriers.The high endothermic capacity of graphite elevated the catalyst surface temperature from 592.1−691.3℃,boosting light-to-thermal conversion.The synergy between photogenerated carriers and localized heat enabled Ni/CeO_(2)-GRA to achieve a CO production rate of 9985.6 mmol/(g·h)(vs 7192.4 mmol/(g·h)for Ni/CeO_(2))and a light-to-fuel efficiency of 21.8%(vs 13.8%for Ni/CeO_(2)).This work provides insights for designing graphite-semiconductor interfaces to advance photothermal catalytic efficiency.
基金supported by R&D the National Key Program of China(Grant No.2021YFA0715503)the Major Project ofShanghai Municipal Science and Technology(Grant No.2018SHZDZX02)the ShanghaiTech Mate rial Device and Soft Matter Nano-fabrication Labs(No.SMN180827).
文摘We report the epitaxial growth of high-quality Al_(0.8)Ga_(0.2)Sb/InAs/Al_(0.8)Ga_(0.2)Sb quantum well films characterized by high carrier mobility and strong spin-orbit coupling.By appropriately optimizing the Al-to-Ga ratio in the AlGaSb barrier layer,the quantum confinement of the heterostructure is significantly enhanced.Alongside a giant magnetoresistance ratio of 3.65×10^(5)%,the two-carrier transport model from Hall measurements reveals an ultra-high electron mobility of 7.18×10^(5)cm^(2)·V^(-1)·s^(-1)at low temperatures.Meanwhile,pronounced Shubnikov-de Haas(SdH)quantum oscillations persist up to 30 K,and their single-frequency feature indicates a well-defined Fermi surface without subband mixing in the two-dimensional electron gas channel.Moreover,the large effective g-factor and tilted-field-induced orbital effect lead to the observation of split SdH peaks at large magnetic fields.Our results validate that AlGaSb/InAs quantum well heterostructures are suitable candidates for constructing energy-efficient topological spintronic devices.
文摘Currently,in STEM environments,female employees are often recognized as minorities due to their positioning or occupancy rate,which may lead to experiences of“imposter syndrome”.This study applies frameworks of mixed-gender discourse,such as limited involvement in activity as an agent,markedness,and gender-differentiated roles,to clarify how women in STEM position themselves or are positioned by the society.Using corpus linguistics and content analysis,it is clarified that female researchers are usually linguistically marked or tend to distinguish themselves as non-experts.Thus,their portrayal within a misogynistic society may considerably interact with how female researchers represent themselves.
文摘Oxysulfide semiconductors are promising photocatalysts for visible light-driven water splitting.For a widely studied narrow-bandgap Sm_(2)Ti_(2)O_(5)S_(2)(STOS),limited bulk charge separation and slow surface reaction heavily restrict its photocatalytic performance.Here,well-crystallized STOS oxysulfide nanosheets,synthesized by a flux-assisted solid-state reaction,were proved to show prominent facet-oriented charge transport property,in which photogenerated electrons migrated to{101}planes and holes to{001}planes of each particle.Hydrogen evolution cocatalysts were therefore precisely positioned on the electron-rich facets to boost the water reduction reaction.In particular,in-situ formation of a Ptshell@Ircore core-shell structure on the electron-rich{101}facets and an IrO_(2) on the hole-accumulated{001}facets greatly assisted the sacrificial photocatalytic H_(2) production over STOS,resulting in an apparent quantum yield as high as 35.9%at 420 nm.By using the highly-active STOS as H_(2) evolution photocatalyst,a Mo:BiVO_(4) as oxygen evolution photocatalyst,and a[Co(bpy)_(3)]^(2+/3+)as redox shuttle,a Z-Scheme overall water splitting system was constructed to achieve a solar-to-hydrogen conversion efficiency of 0.175%.This work not only elucidates the facet-dependent charge transfer mechanism on STOS but also proposes an ideal strategy for enhancing its photocatalytic performance.
基金supported by the Major State Basic Research Development Program of China(No.2022YFA1603703)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB 37040303)+1 种基金National Natural Science Foundation of China(No.12335020)Shanghai Soft X-ray Free Electron Laser Facility beamline project.
文摘Ultrabright femtosecond X-ray pulses generated by X-ray free-electron lasers(XFELs)enable the high-resolution determination of nanoparticle structures without crystallization or freezing.As each particle that interacts with the pulse is destroyed,an aerodynamic lens(ADL)is used to update the particles by focusing them into a narrow beam in real time.Current single-particle imaging(SPI)experiments are limited by an insufficient number of diffraction patterns;therefore,optimized ADLs are required to improve the hit rate and signal-to-noise ratio,particularly for small particles.Herein,an efficient and simple method for designing ADLs and a new ADL specifically designed for SPI using this method are presented.A new method is proposed based on the functional relationship between a key parameter and its influencing parameters in the ADL,which is established through theoretical analysis and numerical simulations.A detailed design process for the new ADL is also introduced.Both simulations and experiments are performed to characterize the behavior of the particles in the ADL.The results show that particles with diameters ranging from 30 to 500 nm can be effectively focused into a narrow beam.In particular,particles smaller than 100 nm exhibit better performance at lower flow rates than the injector currently used in SPI.The new ADL increases the beam density and reduces the gas background noise.This new method facilitates the design of ADLs for SPI and has potential applications in other fields that utilize focused aerosol beams.
基金supported by Start-Up Grant From ShanghaiTech University,2021F0209-000-09Natural Science Foundation of Shanghai Municipality,23ZR1442000。
文摘Transcranial focused ultrasound(tFUS)is an emerging modality with strong potential for non-invasively treating brain disorders.However,the inhomogeneity and complex structure of the skull induce substantial phase aberrations and pressure attenuation;these can distort and shift the acoustic focus,thus hindering the efficiency of tFUS therapy.To achieve effective treatments,phased array transducers combined with aberration correction algorithms are commonly implemented.The present report aims to provide a comprehensive review of the current methods used for tFUS phase aberration correction.We first searched the PubMed and Web of Science databases for studies on phase aberration correction algorithms,identifying 54 articles for review.Relevant information,including the principles of algorithms and refocusing performances,were then extracted from the selected articles.The phase correction algorithms involved two main steps:acoustic field estimation and transmitted pulse adjustment.Our review identified key benchmarks for evaluating the effectiveness of these algorithms,each of which was used in at least three studies.These benchmarks included pressure and intensity,positioning error,focal region size,peak sidelobe ratio,and computational efficiency.Algorithm performances varied under different benchmarks,thus highlighting the importance of application-specific algorithm selection for achieving optimal tFUS therapy outcomes.The present review provides a thorough overview and comparison of various phase correction algorithms,and may offer valuable guidance to tFUS researchers when selecting appropriate phase correction algorithms for specific applications.
基金financial support from the National Natural Science Foundation of China(Nos.22271189,92356301,and 21522105)the Science and Technology Commission of Shanghai Municipality(Nos.21XD1402300,22QC1401500,21JC1401700,and 21DZ2260400)the Double First-Class Initiative Fund of ShanghaiTech University(SYLDX0052022).
文摘In the pursuit of carbon neutrality,hydrogen(H_(2))is often hailed as the ideal fuel for fuel cell vehicles(FCVs)due to its zero-emission nature and high gravimetric energy density.However,its low volumetric density necessitates high-pressure on-board storage(up to 700 bar),which are costly and pose significant safety risks.To cope with these challenges,the U.S.Department of energy(DOE)has set ambitious targets for hydrogen storage systems,aiming for a gravimetric capacity of 6.5 wt%with a volumetric capacity of 50 g L^(-1).Porous crystals,exemplified by metal-organic frameworks(MOFs)[1,2],covalent organic frameworks(COFs),and hydrogen-bonded organic frameworks(HOFs)[3],have shown promise for hydrogen storage at 77 K with delivery at 160 K under significantly lower pressures(≤100 bar).
基金supported by the Major National Science and Technology Infrastructure(No.2208-000000-04-01249628)。
文摘This paper introduces a hybrid fluid-kinetic code,SHYPIC(ShanghaiTech HYbrid PIC code),developed as a baseline framework for simulating plasma dynamics relevant to plasma-jetdriven magneto-inertial fusion(PJMIF).The code integrates a fluid description for electrons and a particle-in-cell(PIC)description for ions,providing computational efficiency and enabling larger-scale simulations.It incorporates ion kinetic effects,allowing accurate simulation of microscale non-equilibrium phenomena.In this initial version,the SHYPIC code is presented along with a series of benchmark tests,including quiet plasma evolution,dispersion relation verification,and the excitation and propagation of externally driven plasma waves.This version does not yet incorporate collisional effects or non-ideal terms(e.g.,resistivity,viscosity,and hyperviscosity)in the electron fluid,which will be included in future developments.The present work lays the foundation for further improvements required for fully simulating the complex dynamics of PJMIF.
文摘Oxidative coupling of methane(OCM)is a catalytic partial oxidation process that directly converts methane into C_(2) products.For this high temperature reaction,understanding the radical behavior through experimental investigation is important in correlating the catalytic activity and the products.In this work,a spatial resolution online mass spectrometry(MS)system was developed and applied to a Mn-Na_(2)WO_(4)/SiO_(2) catalyzed OCM system.In addition to the residue gas analysis,the system obtained the distribution information of the reactants and products in the reactor.At various setting temperatures,all species online MS signals were collected at different positions,mapping the reaction activity covering parameters including temperature,time and space.The distribution behavior of the catalytic activity,selectivity,and apparent activation energy were kinetically analyzed.Selectivity and additional carbon balance analysis strongly supported the radical coupling model of OCM and indicated that after the catalytic bed layer,there is a significant length in the reactor(>2 mm)filled with radicals.Based on the result,a designed new method by tuning the temperature field in the reactor was found effectively to improve the catalytic activity,especially the C_(2) yield from 702 to 773℃.
基金supported by the Major National Science and Technology Infrastructure(No.2208-000000-04-01249628)the Shanghai Science and Technology Commission(No.21DZ1206500)。
文摘We present a hybrid smoothed particle magnetohydrodynamics(SPMHD)code integrating smoothed particle hydrodynamics(SPH)and finite element methods(FEM)to simulate coupled fluid-electromagnetic phenomena.The framework employs SPH for fluid dynamics,addressing large deformations,shocks,and plasma behavior,while FEM resolves electromagnetic fields via Maxwell's equations for magnetic vector and electric scalar potentials,ensuring divergence-free conditions and global current density calculations in conductive region.Operator splitting method couples these modules,enabling real-time integration of magnetic,electric,thermal,and fluid fields.Benchmark tests validate the code against analytical solutions and existing models,including blow-by instability simulations that demonstrate the method's accuracy in capturing fluid-magnetic interactions.Designed for 3D applications,SPMHD offers robust scalability across multiprocessor architectures,establishing it as a versatile tool for plasma physics research.
文摘Fe-based catalysts are widely used for CO_(2)hydrogenation to light olefins(C_(2–4)=);however,precise regulation of active phases and the balance between intermediate reactions remain significant challenges.Herein,we find that the addition of moderate amounts of Ti forms a strong interaction with Fe compositions,modulating the Fe_(3)O_(4)and Fe_(5)C_(2)contents.Enhanced interaction leads to an increased Fe_(5)C_(2)/Fe_(3)O_(4)ratio,which in turn enhances the adsorption of reactants and intermediates,promoting CO hydrogenation to unsaturated alkyl groups and facilitating C–C coupling.Furthermore,the strong Fe-Ti interaction induces the preferential growth of Fe_(5)C_(2)into prismatic structures that expose the(020),(–112),and(311)facets,forming compact active interfacial sites with Fe_(3)O_(4)nanoparticles.These facet and interfacial effects significantly promote the synergistic coupling of the reverse water gas shift and Fischer-Tropsch reactions.The optimized 3K/FeTi catalyst with the highest Fe_(5)C_(2)/Fe_(3)O_(4)ratio of 3.6 achieves a 52.2%CO_(2)conversion rate,with 44.5%selectivity for C2–4=and 9.5%for CO,and the highest space-time yield of 412.0 mg gcat^(–1)h^(–1)for C_(2–4)=.
基金supported by the National Nature Science Foundation of China[Grant Nos.92365204 and 12274298(Z.K.Liu)]the National Key R&D program of China[Grant No.2022YFA1604400/03(Z.K.Liu)]Zhangjiang Laboratory(Y.M.Zhang).The authors thank BL02B at the Shanghai Synchrotron Radiation Facility supported by the National Natural Science Foundation of China(Contract No.11227902).
文摘Fe-based superconductors represent a fascinating class of materials,extensively studied for their complex interplay of superconductivity,magnetism,spin density waves,and nematicity,along with the interactions among these orders.An intriguing yet unexplained phenomenon observed in Fe-based superconductors is the emergence of superconductivity below 25K in the non-superconducting parent compound SrFe_(2)As_(2)following exposure to water at its surface.In this study,we employed in situ angle-resolved photoemission spectroscopy and low-energy electron diffraction to meticulously examine the electronic structure evolution of SrFe_(2)As_(2)upon in situ water dosing.Our findings indicate that water dosing markedly attenuates the spin density wave phase and surface Sr reconstruction while preserving the nematic order in SrFe_(2)As_(2).Furthermore,we detected an enhancement in the spectral weight of bands near the Fermi level.Our observations highlight the critical role of the intricate interplay among various orders induced by water dosing,which effectively modifies the band structure and favors the emergence of superconductivity in SrFe_(2)As_(2).
