Two-dimensional(2D)materials are promising for next-generation electronic devices and systems due to their unique physical properties.The interfacial adhesion plays a vital role not only in the synthesis,transfer and ...Two-dimensional(2D)materials are promising for next-generation electronic devices and systems due to their unique physical properties.The interfacial adhesion plays a vital role not only in the synthesis,transfer and manipulation of 2D materials but also in the manufacture,integration and performance of the functional devices.However,the atomic thickness and limited lateral dimensions of 2D materials make the accurate measurement and modulation of their interfacial adhesion energy challenging.In this review,the recent advances in the measurement and modulation of the interfacial adhesion properties of 2D materials are systematically combed.Experimental methods and relative theoretical models for the adhesion measurement of 2D materials are summarized,with their scope of application and limitations discussed.The measured adhesion energies between 2D materials and various substrates are described in categories,where the typical adhesion modulation strategies of 2D materials are also introduced.Finally,the remaining challenges and opportunities for the interfacial adhesion measurement and modulation of 2D materials are presented.This paper provides guidance for addressing the adhesion issues in devices and systems involving 2D materials.展开更多
Cu^(2+)in copper-based catalysts can facilitate the hydrogenation of the CH_(4)production pathway via the electrochemical carbon dioxide reduction reaction(ECRR).However,Cu^(2+)species in copper oxides are unstable an...Cu^(2+)in copper-based catalysts can facilitate the hydrogenation of the CH_(4)production pathway via the electrochemical carbon dioxide reduction reaction(ECRR).However,Cu^(2+)species in copper oxides are unstable and have been revealed to reduce to Cu^(0)under the applied cathodic potential.In this work,we reported an A-site modulation strategy to stabilize Cu^(2+)in perovskite for efficient ECRR to CH_(4).After the introduction of Ca^(2+)in La_(2)CuO_(4),the obtained LaCa_(0.4)CuO_(3-δ)is stable during ECRR.We achieved a59.6%±3.8%CH4faradaic efficiency at-1.30 V versus reversible hydrogen electrode in H-cell and a partial current density of 155.0 m A/cm^(2)in membrane electrode assembly.DFT calculations and in situ Raman spectroscopy show that Cu^(2+)facilitates the hydrogenation of*CH_(2)O to*CH_(3)O and the further production of CH_(4).This work introduces an efficient strategy to stabilize Cu^(2+)and provides an understanding of Cu^(2+)in promoting ECRR to CH_(4).展开更多
The emergence of SARS-CoV-2 variants and drug-resistant mutants emphasizes the urgent need to develop novel antiviral agents.In the present study,we examined the therapeutic effect of the Chinese medicinal herb,Scutel...The emergence of SARS-CoV-2 variants and drug-resistant mutants emphasizes the urgent need to develop novel antiviral agents.In the present study,we examined the therapeutic effect of the Chinese medicinal herb,Scutellaria barbata D.Don(SBD),against SARS-CoV-2 infection both in vitro and in vivo.Using a viral replicon particle(VRP)-based mouse model of SARS-CoV-2 infection,our study revealed that SBD extracts can reduce viral load in mouse lungs and alleviate the viral induced pneumonia.In vitro antiviral determination further validated the direct acting antiviral efficacy of SBD extracts against SARS-CoV-2 replication.Mechanistic studies demonstrated that SBD can act against SARS-CoV2 replication by targeting both 3-chymotrypsin-like and papain-like cysteine proteases,via a combination of multiple active constituents.Moreover,SBD can modulate the host inflammation response in a bi-directional manner,which also contribute to the mitigation of viral induced acute lung injury.In summary,our study provides SBD as a promising therapeutic agent to combat SARS-CoV-2 infections that merit further development.展开更多
Compositing a secondary phase in Ag_(2)Se can usually tune the electron and phonon scattering to improve the thermoelectric performance.However,the intrinsically high carrier concentration still limits the performance...Compositing a secondary phase in Ag_(2)Se can usually tune the electron and phonon scattering to improve the thermoelectric performance.However,the intrinsically high carrier concentration still limits the performance optimization.Here,we employ a modulation decoration strategy to simultaneously achieve submicron-scale constituents and compositional modification for synergistic optimization of thermoelectric properties.Amorphous nano Sb_(2)S_(3) has been decorated on the surface of Ag_(2)Se powders,and S was added into the Ag_(2)Se matrix through an ion exchange reaction accompanied by the formation of a crystal/amorphous mixed secondary phase of Sb_(2)(S,Se)_(3).The S doping reduced the excessive intrinsic carrier concentration,leading to modified electrical transport properties and significantly reduced electrical thermal conductivity.On the other hand,introducing the S dopants and the crystal/amorphous interfaces into the Ag_(2)Se matrix could increase the lattice anharmonicity,further contributing to the reduced thermal conductivity.Consequently,the Ag_(2)Se-0.4%Sb_(2)S_(3) sample obtains a high average zT value of>1 in the temperature range of 300–390 K.In addition,the maximum cooling temperature difference of over 85 K can be predicted in an Ag_(2)Se/Ag_(2)Se-0.4%Sb_(2)S_(3) segregated module at the hot side temperature of 350 K.展开更多
SnSe_(2) single crystals,as novel n-type plastic thermoelectric materials,present advantages such as envi-ronmental sustainability and cost-effectiveness.Single crystals of SnSe_(2)+x%PbBr_(2)(x=0,0.5,1,2,and 3)with l...SnSe_(2) single crystals,as novel n-type plastic thermoelectric materials,present advantages such as envi-ronmental sustainability and cost-effectiveness.Single crystals of SnSe_(2)+x%PbBr_(2)(x=0,0.5,1,2,and 3)with large size and high quality were successfully synthesized via the Bridgman method.The significant enhancement in power factor and effective suppression of lattice thermal conductivity can be achieved through PbBr_(2) doping,verifying a synergistic optimization of electrical and thermal transport properties.Specifically,Br atoms are effectively incorporated into the Se sites to manipulate the carrier concentra-tion and optimize the power factor,while simultaneously inducing a strong phonon softening effect by introducing Pb atoms at the Sn sites,which leads to a reduced phonon group velocity and a suppres-sion of lattice thermal conductivity.Consequently,SnSe_(2)+2%PbBr_(2) single-crystal sample achieves a peak figure of merit zT of~0.76 and an average zT of~0.51,giving rise to corresponding improvements of~533% and~538%,respectively,compared to the pristine SnSe_(2) sample,thereby outperforming most of the previously reported SnSe_(2)-based materials.This work provides a viable approach for promoting the thermoelectric performance of SnSe^(2)-based single crystals across a broad temperature range and supports the advancement of plastic thermoelectric materials.展开更多
Electronic-state modulation strategy offers great potential in designing RuO_(2)-based bifunctionalelectrocatalysts for rechargeable Zn-air batteries(ZABs).Various three-dimensional(3D)transition metal oxides are atte...Electronic-state modulation strategy offers great potential in designing RuO_(2)-based bifunctionalelectrocatalysts for rechargeable Zn-air batteries(ZABs).Various three-dimensional(3D)transition metal oxides are attempted to couple with RuO_(2)for constructing an appropriate Ru—O—M interface.This work aims to construct Co_(3)O_(4)-RuO_(2)heterostructures on carbon sheets(Co_(3)O_(4)/RuO_(2)/NCNS)for boosting electronic transfer and regulation.Experiments and theoretical calculations identify the electronic transfer from Co_(3)O_(4)to RuO_(2)that modulates the electronic structure of metal surfaces/interfaces.Specifically,it leads to the increase in Co3+content,electron-rich state at RuO_(2)surface and electronic accumulation at interfaces.Moreover,this electronic-state modulation optimizes the d-band center in Co_(3)O_(4)/RuO_(2)that lowers the reaction barriers and endows interfaces as the biggest contributor to oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)performance,The Co_(3)O_(4)/RuO_(2)/NCNS shows a quite low potential difference of 0.62 V and remarkable durability for ORR/OER.Co_(3)O_(4)/RuO_(2)/NCNS-assembled ZABs exhibit an excellent specific capacity of 818.3 mA h g^(-1)and a superior lifespan over 750 h.展开更多
The electrochemical CO_(2) reduction(ECR)into value-added products presents an appealing approach to mitigate CO_(2) emission caused by excess consumption of fossil fuels.To obtain high catalytic activity and selectiv...The electrochemical CO_(2) reduction(ECR)into value-added products presents an appealing approach to mitigate CO_(2) emission caused by excess consumption of fossil fuels.To obtain high catalytic activity and selectivity toward target product in ECR,designing and developing a stable and efficient electrocatalyst is of significant importance.To date,metal nanomaterials have been widely applied as electrocatalysts for ECR due to their unique physicochemical properties.The structural modulation of metal nanomaterials is an attractive strategy to improve the catalytic performance.In this review,the recent progress of structural modulation,including size,facet,grain boundary,composition,interface,ligand modification,and crystal phase,is systematically summarized from both theoretical and experimental aspects.Finally,the opportunities and perspectives of structural modulation of metal nanomaterials for ECR are proposed.展开更多
Effective colour modulation of upconversion emissions in lanthanide-doped nanomaterials becomes even more important for fundamental and applied research.Herein,on the one hand,by raising the content of doped Yb^(3+)fr...Effective colour modulation of upconversion emissions in lanthanide-doped nanomaterials becomes even more important for fundamental and applied research.Herein,on the one hand,by raising the content of doped Yb^(3+)from 10 mol%to 50 mol%,a significant increase of the red/green emission ratio from 4.0 to 68.2 is observed in K_(2)NaScF_(6):Yb/Er nanocrystals.This yellow to red colour change is attributed to the increased cross relaxation between Er^(3+)and Yb^(3+)caused by the increased Yb^(3+)amount,^(4) S_(3/2)(Er^(3+))^(+2) F7/2(Yb^(3+))→4 I13/2(Er^(3+))^(+2) F5/2(Yb^(3+)).On the other hand,the upconversion green and red emission of K_(2)NaScF_(6):Yb/Er(20/2 mol%)nanocrystals are intensified 10.6 and 8.8 folds,respectively,after an active shell(K_(2)NaScF_(6):Yb)is epitaxially grown,which are more effective than the7.4-and 6.4-fold enhancement from an inert shell(K_(2)NaScF_(6))growth.Moreover,the shell thickness from2.85 to 9.5 nm through controlling the molar ratio of shell-precursor to core from 1:2 to 3:1 can be easily realized.This study will provide more opportunities for the application of K_(2)NaScF_(6):Yb/Ln nanoparticles in varied fields such as theranostics,photovoltaics,and photocatalysis.展开更多
Modulational instability is an important area of research with important practical and theoretical significance in fluid mechanics,optics,plasma physics,and military and communication engineering.In this paper,using m...Modulational instability is an important area of research with important practical and theoretical significance in fluid mechanics,optics,plasma physics,and military and communication engineering.In this paper,using multiscale analysis and a perturbation expansion method,starting from the quasi-geostrophic potential vortex equation,a new(2+1)-dimensional highorder nonlinear Schrodinger equation describing Rossby waves in stratified fluids is obtained.Based on this equation,conditions for the occurrence of modulational instability of Rossby waves are analyzed.Moreover,the effects of factors such as the dimension and order of the equation and the latitude at which Rossby waves occur on modulational instability are discussed.It is found that the(2+1)-dimensional equation provides a good description of the modulational instability of Rossby waves on a plane.The high-order terms affect the modulational instability,and it is found that instability is more likely to occur at high latitudes.展开更多
CeO2 film plays an essential role in nucleation and growth of YBa2 Cu3 O（7-x）（YBCO） films. In this work,the dependence of superconducting properties of YBCO on CeO2 films with different thicknesses was investigate...CeO2 film plays an essential role in nucleation and growth of YBa2 Cu3 O（7-x）（YBCO） films. In this work,the dependence of superconducting properties of YBCO on CeO2 films with different thicknesses was investigated,in order to achieve fabrication of high-performance YBCO coated conductors in industrial scale. The crystalline structure and morphology of CeO2 films with thickness ranging from 21 to 563 nm were systematically characterized by means of X-ray diffraction（XRD）, atomic force microscope（AFM） and reflection high-energy electron diffraction（RHEED）. Additional focus was addressed on evolution of the surface quality of CeO2 films with thickness increasing. The results show that at the optimal thickness of 221 nm, CeO2 film exhibits sharp in-plane and out-of-plane texture with full width of half maximum（FWHM） values of 5.9° and 1.8°, respectively, and smooth surface with a mean root-mean-square（RMS） roughness value as low as 0.6 nm. Combing RHEED and transmission electron microscope（TEM） cross-sectional analysis, it is found that nucleation and growth of CeO2 films at early stage remain in island growth mode with rougher surface,while further increasing the thickness beyond the optimal thickness leads to weak surface quality, consequently resulting in degradation of superconductor layers deposited subsequently. Eventually, a critical current density（Jc） as high as 4.6×10-6 A·cm-（-2）（77 K, self-field） is achieved on a YBCO film on a thickness-modulated CeO2/MgO/Y2 O3/Al2 O3/C276 architecture, demonstrating the advantages of CeO2 films as buffer layer in high-throughput manufacture of coated conductors.展开更多
A 1.7-at.%Er:CaF_(2)crystal was synthesized by temperature gradient method.The Er:CaF_(2)crystal was applied in acousto-optically Q-switched laser at mid-infrared region for the first time.Using a Te O_(2)-based cryst...A 1.7-at.%Er:CaF_(2)crystal was synthesized by temperature gradient method.The Er:CaF_(2)crystal was applied in acousto-optically Q-switched laser at mid-infrared region for the first time.Using a Te O_(2)-based crystal as Q-switcher,we obtained a laser diode(LD)end-pumped Er:CaF_(2)laser with the highest single pulse energy up to 0.49 mJ and maximum peak power of 0.56 kW under 6.34-W absorbed pump power.The implication of these results is that the low-doped Er:CaF_(2)crystal exhibits promising optical properties in solid-state lasers.展开更多
The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-n...The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio fuzes.To solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is proposed.First,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)signal.Then,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for classification.The DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical algorithms.The trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.展开更多
CO_(2)electroreduction(CO_(2)RR)represents a promising negative-carbon technology,which is in urgent need for efficient and high-selectivity catalysts.Here,a support control strategy is employed for precise surface en...CO_(2)electroreduction(CO_(2)RR)represents a promising negative-carbon technology,which is in urgent need for efficient and high-selectivity catalysts.Here,a support control strategy is employed for precise surface engineering of charge-asymmetry nanocluster catalyst(CuZnSCN),in which zinc and copper atoms together form a metal cluster loaded on sulfur and nitrogen co-etched carbon matrix.The synergistic promotion mechanism of CO_(2)RR by Cu–Zn atom interactions and sulfur–nitrogen atom doping was investigated.A CO partial current density of 74.1 mA cm^(-2)was achieved in an alkaline electrolyte,as well as a considerable CO Faraday efficiency of 97.7%.In situ XAS(X-ray absorption spectroscopy)showed that the stabilization of Cu^(+)and Zn^(2+)species in the nanoclusters and doped sulfur atoms during the CO_(2)RR process contributes to the sustained adsorption of protons and the generation and conversion of the CO.This work verifies the possibility of metal-support and intermetallic interactions to synergistically enhance electrochemical catalytic performance and provides ideas for further bimetallic cluster catalyst development.展开更多
Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four plan...Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.展开更多
KH2PO4 crystal is a crucial optical component of inertial confinement fusion. Modulation of an incident laser by surface micro-defects will induce the growth of surface damage, which largely restricts the enhancement ...KH2PO4 crystal is a crucial optical component of inertial confinement fusion. Modulation of an incident laser by surface micro-defects will induce the growth of surface damage, which largely restricts the enhancement of the laser induced damage threshold. The modulation of an incident laser by using different kinds of surface defects are simulated by employing the three-dimensional finite-difference time-domain method. The results indicate that after the modulation of surface defects, the light intensity distribution inside the crystal is badly distorted, with the light intensity enhanced symmetrically. The relations between modulation properties and defect geometries （e.g., width, morphology, and depth of defects） are quite different for different defects. The modulation action is most obvious when the width of surface defects reaches 1.064 p-m. For defects with smooth morphology, such as spherical pits, the degree of modulation is the smallest and the light intensity distribution seems relatively uniform. The degree of modulation increases rapidly with the increase of the depth of surface defects and becomes stable when the depth reaches a critical value. The critical depth is 1.064 μm for cuboid pits and radial cracks, while for ellipsoidal pits the value depends on both the width and the length of the defects.展开更多
To realize the continuous production of hydrogen energy,the efficient photocatalysts are required in the heterogeneous reaction for water splitting.Herein,we reported a surface modulation strategy,via doping oxygen at...To realize the continuous production of hydrogen energy,the efficient photocatalysts are required in the heterogeneous reaction for water splitting.Herein,we reported a surface modulation strategy,via doping oxygen atoms to tune the surface state of ZnIn_(2)S_(4)nanosheets with cocatalyst MoS_(2)modification,to enhance water adsorption and surface catalytic reaction for boosting the photocatalytic activity.Consequently,MoS_(2)/O-ZnIn_(2)S_(4)photocatalysts showed a remarkably superior photocatalytic H_(2)production performance of 4.002 mmol g^(-1)h^(-1)and an apparent quantum yield(AQY)of~2.53%,5.4 folds higher than ZnIn_(2)S_(4).Using operando infrared spectroscopy and DFT calculation,we revealed the dynamic structural evolution,as well as the active sites for water adsorption and the catalytic reaction at the MoS_(2)/O ZnIn_(2)S_(4)interface.This work reveals the effect of surface modulation on the photocatalytic activity for MoS_(2)/O-ZnIn_(2)S_(4)and offers a feasible method to devise excellent nanomaterial photocatalysts for H_(2)production.展开更多
A reduction in the track width of magnetic recording systems results in a welcome increase in Areal Density(AD),but can severely deteriorate system performance in the unfortunate appearance of extreme Inter-Track Inte...A reduction in the track width of magnetic recording systems results in a welcome increase in Areal Density(AD),but can severely deteriorate system performance in the unfortunate appearance of extreme Inter-Track Interference(ITI).The effect of severe ITI may be mitigated by using coding schemes.In this paper,therefore,we present a rate-5/62-Dimensional(2D)modulation code based on a proposed Single-Reader/Two-track Reading(SRTR)technique to cope with this serious problem in staggered Bit-Pattemed Magnetic Recording(BPMR)systems.We then evaluate the Bit-Error Rate(BER)performance of the proposed system in the presence of media noises,e.g.,position and size fluctuations.Our simulation results indicate that,at the same User Density(UD),the proposed system performs better than an uncoded system by about 1.0 dB at the BER of 105 and is also superior to the conventional recording system.展开更多
The KH2PO4 crystal is a key component in optical systems of inertial confinement fusion （ICF）. The microwaviness on a KH2PO4 crystal surface is strongly related to its damage threshold which is a key parameter for a...The KH2PO4 crystal is a key component in optical systems of inertial confinement fusion （ICF）. The microwaviness on a KH2PO4 crystal surface is strongly related to its damage threshold which is a key parameter for application. To study the laser induced damage mechanism caused by microwaviness, in this paper the near-field modulation properties of microwaviness to the incident wave are discussed by the Fourier modal method. Research results indicate that the microwaviness on the machined surface will distort the incident wave and thus lead to non-uniform distribution of the light intensity inside the crystal; in a common range of microwaviness amplitude, the light intensity modulation degree increases about 0.03 whenever the microwaviness amplitude increases 10 nm; 1 order diffraction efficiencies are the key factors responsible for light intensity modulation inside the crystal; the light intensity modulation is just around the microwaviness in the form of an evanescent wave, not inside the crystal when the microwaviness period is below 0.712μm; light intensity modulation degree has two extreme points in microwaviness periods of 1.064μm and 1.6μm, remains unchanged between periods of 3μm and 150μm, and descends above the period of 150μm to 920μm.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12002133,12372109,and 11972171)the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20200590 and BK20180031)+4 种基金the Fundamental Research Funds for the Central Universities(Grant No.JUSRP121040)the National Key R&D Program of China(Grant No.2023YFB4605101)the 111 project(Grant No.B18027)the Open Fund of Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education(Grant No.NJ2020003)the Sixth Phase of Jiangsu Province“333 High Level Talent Training Project”Second Level Talents.
文摘Two-dimensional(2D)materials are promising for next-generation electronic devices and systems due to their unique physical properties.The interfacial adhesion plays a vital role not only in the synthesis,transfer and manipulation of 2D materials but also in the manufacture,integration and performance of the functional devices.However,the atomic thickness and limited lateral dimensions of 2D materials make the accurate measurement and modulation of their interfacial adhesion energy challenging.In this review,the recent advances in the measurement and modulation of the interfacial adhesion properties of 2D materials are systematically combed.Experimental methods and relative theoretical models for the adhesion measurement of 2D materials are summarized,with their scope of application and limitations discussed.The measured adhesion energies between 2D materials and various substrates are described in categories,where the typical adhesion modulation strategies of 2D materials are also introduced.Finally,the remaining challenges and opportunities for the interfacial adhesion measurement and modulation of 2D materials are presented.This paper provides guidance for addressing the adhesion issues in devices and systems involving 2D materials.
基金financial support from the National Natural Science Foundation of China(Nos.22308246,22478278)Central Government Guides the Special Fund Projects of Local Scientific and Technological Development(No.YDZJSX20231A015)the Fundamental Research Program of Shanxi Province(No.202203021212266)。
文摘Cu^(2+)in copper-based catalysts can facilitate the hydrogenation of the CH_(4)production pathway via the electrochemical carbon dioxide reduction reaction(ECRR).However,Cu^(2+)species in copper oxides are unstable and have been revealed to reduce to Cu^(0)under the applied cathodic potential.In this work,we reported an A-site modulation strategy to stabilize Cu^(2+)in perovskite for efficient ECRR to CH_(4).After the introduction of Ca^(2+)in La_(2)CuO_(4),the obtained LaCa_(0.4)CuO_(3-δ)is stable during ECRR.We achieved a59.6%±3.8%CH4faradaic efficiency at-1.30 V versus reversible hydrogen electrode in H-cell and a partial current density of 155.0 m A/cm^(2)in membrane electrode assembly.DFT calculations and in situ Raman spectroscopy show that Cu^(2+)facilitates the hydrogenation of*CH_(2)O to*CH_(3)O and the further production of CH_(4).This work introduces an efficient strategy to stabilize Cu^(2+)and provides an understanding of Cu^(2+)in promoting ECRR to CH_(4).
基金supported by the National Natural Science Foundation of China(82274204 and 82104134)the Natural Science Foundation of Shandong Province,China(ZR2024QH110)+1 种基金the Major Basic Program of Shandong Natural Science Foundation,China(ZR2021ZD17)the Project of Youth Innovation Team of Shandong Province(2022KJ254).
文摘The emergence of SARS-CoV-2 variants and drug-resistant mutants emphasizes the urgent need to develop novel antiviral agents.In the present study,we examined the therapeutic effect of the Chinese medicinal herb,Scutellaria barbata D.Don(SBD),against SARS-CoV-2 infection both in vitro and in vivo.Using a viral replicon particle(VRP)-based mouse model of SARS-CoV-2 infection,our study revealed that SBD extracts can reduce viral load in mouse lungs and alleviate the viral induced pneumonia.In vitro antiviral determination further validated the direct acting antiviral efficacy of SBD extracts against SARS-CoV-2 replication.Mechanistic studies demonstrated that SBD can act against SARS-CoV2 replication by targeting both 3-chymotrypsin-like and papain-like cysteine proteases,via a combination of multiple active constituents.Moreover,SBD can modulate the host inflammation response in a bi-directional manner,which also contribute to the mitigation of viral induced acute lung injury.In summary,our study provides SBD as a promising therapeutic agent to combat SARS-CoV-2 infections that merit further development.
基金financially supported by the National Natural Science Foundation of China(Nos.52472105,52272246,and 12074015)the Sichuan Science and Technology Program(Nos.2024YFHZ0309 and 2023NSFSC1596)the State Key Laboratory for Mechanical Behavior of Materials(No.20232509).
文摘Compositing a secondary phase in Ag_(2)Se can usually tune the electron and phonon scattering to improve the thermoelectric performance.However,the intrinsically high carrier concentration still limits the performance optimization.Here,we employ a modulation decoration strategy to simultaneously achieve submicron-scale constituents and compositional modification for synergistic optimization of thermoelectric properties.Amorphous nano Sb_(2)S_(3) has been decorated on the surface of Ag_(2)Se powders,and S was added into the Ag_(2)Se matrix through an ion exchange reaction accompanied by the formation of a crystal/amorphous mixed secondary phase of Sb_(2)(S,Se)_(3).The S doping reduced the excessive intrinsic carrier concentration,leading to modified electrical transport properties and significantly reduced electrical thermal conductivity.On the other hand,introducing the S dopants and the crystal/amorphous interfaces into the Ag_(2)Se matrix could increase the lattice anharmonicity,further contributing to the reduced thermal conductivity.Consequently,the Ag_(2)Se-0.4%Sb_(2)S_(3) sample obtains a high average zT value of>1 in the temperature range of 300–390 K.In addition,the maximum cooling temperature difference of over 85 K can be predicted in an Ag_(2)Se/Ag_(2)Se-0.4%Sb_(2)S_(3) segregated module at the hot side temperature of 350 K.
基金financially supported by the National Natural Science Foundation of China(Nos.52125103,52371212,52071041,12204080,12374002)the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Nos.KJQN202400604,KJQN202200623,KJZD-K202100602)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.2024IAIS-ZX002,2023CDJKYJH006)the Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-MSX0382).
文摘SnSe_(2) single crystals,as novel n-type plastic thermoelectric materials,present advantages such as envi-ronmental sustainability and cost-effectiveness.Single crystals of SnSe_(2)+x%PbBr_(2)(x=0,0.5,1,2,and 3)with large size and high quality were successfully synthesized via the Bridgman method.The significant enhancement in power factor and effective suppression of lattice thermal conductivity can be achieved through PbBr_(2) doping,verifying a synergistic optimization of electrical and thermal transport properties.Specifically,Br atoms are effectively incorporated into the Se sites to manipulate the carrier concentra-tion and optimize the power factor,while simultaneously inducing a strong phonon softening effect by introducing Pb atoms at the Sn sites,which leads to a reduced phonon group velocity and a suppres-sion of lattice thermal conductivity.Consequently,SnSe_(2)+2%PbBr_(2) single-crystal sample achieves a peak figure of merit zT of~0.76 and an average zT of~0.51,giving rise to corresponding improvements of~533% and~538%,respectively,compared to the pristine SnSe_(2) sample,thereby outperforming most of the previously reported SnSe_(2)-based materials.This work provides a viable approach for promoting the thermoelectric performance of SnSe^(2)-based single crystals across a broad temperature range and supports the advancement of plastic thermoelectric materials.
基金supported by the National Natural Science Foundation of China(52273264)the Outstanding Youth Fund of Heilongjiang Province(JQ 2020B002).
文摘Electronic-state modulation strategy offers great potential in designing RuO_(2)-based bifunctionalelectrocatalysts for rechargeable Zn-air batteries(ZABs).Various three-dimensional(3D)transition metal oxides are attempted to couple with RuO_(2)for constructing an appropriate Ru—O—M interface.This work aims to construct Co_(3)O_(4)-RuO_(2)heterostructures on carbon sheets(Co_(3)O_(4)/RuO_(2)/NCNS)for boosting electronic transfer and regulation.Experiments and theoretical calculations identify the electronic transfer from Co_(3)O_(4)to RuO_(2)that modulates the electronic structure of metal surfaces/interfaces.Specifically,it leads to the increase in Co3+content,electron-rich state at RuO_(2)surface and electronic accumulation at interfaces.Moreover,this electronic-state modulation optimizes the d-band center in Co_(3)O_(4)/RuO_(2)that lowers the reaction barriers and endows interfaces as the biggest contributor to oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)performance,The Co_(3)O_(4)/RuO_(2)/NCNS shows a quite low potential difference of 0.62 V and remarkable durability for ORR/OER.Co_(3)O_(4)/RuO_(2)/NCNS-assembled ZABs exhibit an excellent specific capacity of 818.3 mA h g^(-1)and a superior lifespan over 750 h.
基金financially supported by the National Key R&D Program(N os.2017 YF A0204503 and 2016YFB0401100)the National Natural Science Foundation of China(Nos.91833306,21875158,51633006 and 51703159)。
文摘The electrochemical CO_(2) reduction(ECR)into value-added products presents an appealing approach to mitigate CO_(2) emission caused by excess consumption of fossil fuels.To obtain high catalytic activity and selectivity toward target product in ECR,designing and developing a stable and efficient electrocatalyst is of significant importance.To date,metal nanomaterials have been widely applied as electrocatalysts for ECR due to their unique physicochemical properties.The structural modulation of metal nanomaterials is an attractive strategy to improve the catalytic performance.In this review,the recent progress of structural modulation,including size,facet,grain boundary,composition,interface,ligand modification,and crystal phase,is systematically summarized from both theoretical and experimental aspects.Finally,the opportunities and perspectives of structural modulation of metal nanomaterials for ECR are proposed.
基金Project supported by the National Natural Science Foundation of China(21871137,21671101)the Research Fund for the Doctoral Program of Liaocheng University(318051832)the Innovation Team of Higher Educational Science and Technology Program of Shandong Province(2019KIA025)。
文摘Effective colour modulation of upconversion emissions in lanthanide-doped nanomaterials becomes even more important for fundamental and applied research.Herein,on the one hand,by raising the content of doped Yb^(3+)from 10 mol%to 50 mol%,a significant increase of the red/green emission ratio from 4.0 to 68.2 is observed in K_(2)NaScF_(6):Yb/Er nanocrystals.This yellow to red colour change is attributed to the increased cross relaxation between Er^(3+)and Yb^(3+)caused by the increased Yb^(3+)amount,^(4) S_(3/2)(Er^(3+))^(+2) F7/2(Yb^(3+))→4 I13/2(Er^(3+))^(+2) F5/2(Yb^(3+)).On the other hand,the upconversion green and red emission of K_(2)NaScF_(6):Yb/Er(20/2 mol%)nanocrystals are intensified 10.6 and 8.8 folds,respectively,after an active shell(K_(2)NaScF_(6):Yb)is epitaxially grown,which are more effective than the7.4-and 6.4-fold enhancement from an inert shell(K_(2)NaScF_(6))growth.Moreover,the shell thickness from2.85 to 9.5 nm through controlling the molar ratio of shell-precursor to core from 1:2 to 3:1 can be easily realized.This study will provide more opportunities for the application of K_(2)NaScF_(6):Yb/Ln nanoparticles in varied fields such as theranostics,photovoltaics,and photocatalysis.
基金supported by the National Natural Science Foundation of China(No.11975143)。
文摘Modulational instability is an important area of research with important practical and theoretical significance in fluid mechanics,optics,plasma physics,and military and communication engineering.In this paper,using multiscale analysis and a perturbation expansion method,starting from the quasi-geostrophic potential vortex equation,a new(2+1)-dimensional highorder nonlinear Schrodinger equation describing Rossby waves in stratified fluids is obtained.Based on this equation,conditions for the occurrence of modulational instability of Rossby waves are analyzed.Moreover,the effects of factors such as the dimension and order of the equation and the latitude at which Rossby waves occur on modulational instability are discussed.It is found that the(2+1)-dimensional equation provides a good description of the modulational instability of Rossby waves on a plane.The high-order terms affect the modulational instability,and it is found that instability is more likely to occur at high latitudes.
基金financially supported by the International Thermonuclear Experimental Reactor (ITER) Project from Ministry of Science and Technology of China (No.2011GB113004)the National High Technology Research and Development Program of China(No.2014AA032402)+1 种基金the Shanghai Commission of Science and Technology (Nos.11DZ1100402 and 13DZ0500100)the Natural Science Foundation of China(Nos.11204174 and 51372150)
文摘CeO2 film plays an essential role in nucleation and growth of YBa2 Cu3 O（7-x）（YBCO） films. In this work,the dependence of superconducting properties of YBCO on CeO2 films with different thicknesses was investigated,in order to achieve fabrication of high-performance YBCO coated conductors in industrial scale. The crystalline structure and morphology of CeO2 films with thickness ranging from 21 to 563 nm were systematically characterized by means of X-ray diffraction（XRD）, atomic force microscope（AFM） and reflection high-energy electron diffraction（RHEED）. Additional focus was addressed on evolution of the surface quality of CeO2 films with thickness increasing. The results show that at the optimal thickness of 221 nm, CeO2 film exhibits sharp in-plane and out-of-plane texture with full width of half maximum（FWHM） values of 5.9° and 1.8°, respectively, and smooth surface with a mean root-mean-square（RMS） roughness value as low as 0.6 nm. Combing RHEED and transmission electron microscope（TEM） cross-sectional analysis, it is found that nucleation and growth of CeO2 films at early stage remain in island growth mode with rougher surface,while further increasing the thickness beyond the optimal thickness leads to weak surface quality, consequently resulting in degradation of superconductor layers deposited subsequently. Eventually, a critical current density（Jc） as high as 4.6×10-6 A·cm-（-2）（77 K, self-field） is achieved on a YBCO film on a thickness-modulated CeO2/MgO/Y2 O3/Al2 O3/C276 architecture, demonstrating the advantages of CeO2 films as buffer layer in high-throughput manufacture of coated conductors.
基金the National Natural Science Foundation of China(Grant Nos.11974220,61925508,61905265,and 12104271)the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2021LLZ008 and ZR2021QA030)+1 种基金the Fund from Science and Technology Commission of Shanghai Municipality(Grant No.20511107400)CAS Interdisciplinary Innovation Team(Grant No.JCTD-2019-12).
文摘A 1.7-at.%Er:CaF_(2)crystal was synthesized by temperature gradient method.The Er:CaF_(2)crystal was applied in acousto-optically Q-switched laser at mid-infrared region for the first time.Using a Te O_(2)-based crystal as Q-switcher,we obtained a laser diode(LD)end-pumped Er:CaF_(2)laser with the highest single pulse energy up to 0.49 mJ and maximum peak power of 0.56 kW under 6.34-W absorbed pump power.The implication of these results is that the low-doped Er:CaF_(2)crystal exhibits promising optical properties in solid-state lasers.
基金National Natural Science Foundation of China under Grant No.61973037China Postdoctoral Science Foundation 2022M720419 to provide fund for conducting experiments。
文摘The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio fuzes.To solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is proposed.First,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)signal.Then,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for classification.The DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical algorithms.The trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.
基金financially supported by the National Natural Science Foundation of China(No.22375019)Beijing Institute of Technology Research Fund Program for Young Scholars(No.3090012221909)
文摘CO_(2)electroreduction(CO_(2)RR)represents a promising negative-carbon technology,which is in urgent need for efficient and high-selectivity catalysts.Here,a support control strategy is employed for precise surface engineering of charge-asymmetry nanocluster catalyst(CuZnSCN),in which zinc and copper atoms together form a metal cluster loaded on sulfur and nitrogen co-etched carbon matrix.The synergistic promotion mechanism of CO_(2)RR by Cu–Zn atom interactions and sulfur–nitrogen atom doping was investigated.A CO partial current density of 74.1 mA cm^(-2)was achieved in an alkaline electrolyte,as well as a considerable CO Faraday efficiency of 97.7%.In situ XAS(X-ray absorption spectroscopy)showed that the stabilization of Cu^(+)and Zn^(2+)species in the nanoclusters and doped sulfur atoms during the CO_(2)RR process contributes to the sustained adsorption of protons and the generation and conversion of the CO.This work verifies the possibility of metal-support and intermetallic interactions to synergistically enhance electrochemical catalytic performance and provides ideas for further bimetallic cluster catalyst development.
文摘Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50875066)
文摘KH2PO4 crystal is a crucial optical component of inertial confinement fusion. Modulation of an incident laser by surface micro-defects will induce the growth of surface damage, which largely restricts the enhancement of the laser induced damage threshold. The modulation of an incident laser by using different kinds of surface defects are simulated by employing the three-dimensional finite-difference time-domain method. The results indicate that after the modulation of surface defects, the light intensity distribution inside the crystal is badly distorted, with the light intensity enhanced symmetrically. The relations between modulation properties and defect geometries （e.g., width, morphology, and depth of defects） are quite different for different defects. The modulation action is most obvious when the width of surface defects reaches 1.064 p-m. For defects with smooth morphology, such as spherical pits, the degree of modulation is the smallest and the light intensity distribution seems relatively uniform. The degree of modulation increases rapidly with the increase of the depth of surface defects and becomes stable when the depth reaches a critical value. The critical depth is 1.064 μm for cuboid pits and radial cracks, while for ellipsoidal pits the value depends on both the width and the length of the defects.
基金supported by the National Natural Science Foundation of China(22005164)the Natural Science Foundation of Shandong Province(BS2015CL002)the Basic Research Project of Qingdao Source Innovation Program Fund(17-1-1-82-jch)。
文摘To realize the continuous production of hydrogen energy,the efficient photocatalysts are required in the heterogeneous reaction for water splitting.Herein,we reported a surface modulation strategy,via doping oxygen atoms to tune the surface state of ZnIn_(2)S_(4)nanosheets with cocatalyst MoS_(2)modification,to enhance water adsorption and surface catalytic reaction for boosting the photocatalytic activity.Consequently,MoS_(2)/O-ZnIn_(2)S_(4)photocatalysts showed a remarkably superior photocatalytic H_(2)production performance of 4.002 mmol g^(-1)h^(-1)and an apparent quantum yield(AQY)of~2.53%,5.4 folds higher than ZnIn_(2)S_(4).Using operando infrared spectroscopy and DFT calculation,we revealed the dynamic structural evolution,as well as the active sites for water adsorption and the catalytic reaction at the MoS_(2)/O ZnIn_(2)S_(4)interface.This work reveals the effect of surface modulation on the photocatalytic activity for MoS_(2)/O-ZnIn_(2)S_(4)and offers a feasible method to devise excellent nanomaterial photocatalysts for H_(2)production.
基金This work was patially supported by the Thailand Research Fund under the grant number RSA6080051,College of Advanced Manufacturing Innovation(AMD),and King Mongkut's Institute of Technology Ladkrabang(KMIIL),Thailand.
文摘A reduction in the track width of magnetic recording systems results in a welcome increase in Areal Density(AD),but can severely deteriorate system performance in the unfortunate appearance of extreme Inter-Track Interference(ITI).The effect of severe ITI may be mitigated by using coding schemes.In this paper,therefore,we present a rate-5/62-Dimensional(2D)modulation code based on a proposed Single-Reader/Two-track Reading(SRTR)technique to cope with this serious problem in staggered Bit-Pattemed Magnetic Recording(BPMR)systems.We then evaluate the Bit-Error Rate(BER)performance of the proposed system in the presence of media noises,e.g.,position and size fluctuations.Our simulation results indicate that,at the same User Density(UD),the proposed system performs better than an uncoded system by about 1.0 dB at the BER of 105 and is also superior to the conventional recording system.
基金Project supported by the National Natural Science Foundation of China (Grant No.50875066)the National High Technology Research and Development Program of China (Grant No.2009AA044305)
文摘The KH2PO4 crystal is a key component in optical systems of inertial confinement fusion （ICF）. The microwaviness on a KH2PO4 crystal surface is strongly related to its damage threshold which is a key parameter for application. To study the laser induced damage mechanism caused by microwaviness, in this paper the near-field modulation properties of microwaviness to the incident wave are discussed by the Fourier modal method. Research results indicate that the microwaviness on the machined surface will distort the incident wave and thus lead to non-uniform distribution of the light intensity inside the crystal; in a common range of microwaviness amplitude, the light intensity modulation degree increases about 0.03 whenever the microwaviness amplitude increases 10 nm; 1 order diffraction efficiencies are the key factors responsible for light intensity modulation inside the crystal; the light intensity modulation is just around the microwaviness in the form of an evanescent wave, not inside the crystal when the microwaviness period is below 0.712μm; light intensity modulation degree has two extreme points in microwaviness periods of 1.064μm and 1.6μm, remains unchanged between periods of 3μm and 150μm, and descends above the period of 150μm to 920μm.
