Fracture-cave reservoirs in carbonate rocks are characterized by a large difference in fracture and cavity size,and a sharp variation in lithology and velocity,thereby resulting in complex diffraction responses.Some s...Fracture-cave reservoirs in carbonate rocks are characterized by a large difference in fracture and cavity size,and a sharp variation in lithology and velocity,thereby resulting in complex diffraction responses.Some small-scale fractures and caves cause weak diffraction energy and would be obscured by the continuous reflection layer in the imaging section,thereby making them difficult to identify.This paper develops a diffraction wave imaging method in the dip domain,which can improve the resolution of small-scale diffractors in the imaging section.Common imaging gathers(CIGs)in the dip domain are extracted by Gaussian beam migration.In accordance with the geometric differences of the diffraction being quasilinear and the reflection being quasiparabolic in the dip-domain CIGs,we use slope analysis technique to filter waves and use Hanning window function to improve the diffraction wave separation level.The diffraction dip-domain CIGs are stacked horizontally to obtain diffraction imaging results.Wavefield separation analysis and numerical modeling results show that the slope analysis method,together with Hanning window filtering,can better suppress noise to obtain the diffraction dip-domain CIGs,thereby improving the clarity of the diffractors in the diffraction imaging section.展开更多
We discuss the nonlinear Schr6dinger equation with variable coefficients in 21） graded-index waveguides with different distributed transverse diffractions and obtain exact bright and dark soliton solutions. Based on ...We discuss the nonlinear Schr6dinger equation with variable coefficients in 21） graded-index waveguides with different distributed transverse diffractions and obtain exact bright and dark soliton solutions. Based on these solutions, we mainly investigate the dynamical behaviors of solitons in three different diffraction decreasing waveguides with the hyperbolic, Gaussian and Logarithmic profiles. Results indicate that for the same parameters, the amplitude of bright solitons in the Logarithmic profile and the amplitude of dark solitons in the Gaussian profile are biggest respectively, and the amplitude in the hyperbolic profile is smallest, while the width of solitons has the opposite case.展开更多
Electrically driven structural patterns in liquid crystals(LCs)have attracted considerable attention due to their electrooptical applications.Here,we disclose various appealing reconfigurable LC microstructures in a d...Electrically driven structural patterns in liquid crystals(LCs)have attracted considerable attention due to their electrooptical applications.Here,we disclose various appealing reconfigurable LC microstructures in a dual frequency nematic LC(DFNLC)owing to the electroconvection-induced distortion of the LC director,including one-dimensional rolls,chevron pattern,two-dimensional grids,and unstable chaos.These patterns can be switched among each other,and the lattice constants are modulated by tuning the amplitude and frequency of the applied electric field.The electrically switchable self-assembled microstructures and their beam steering capabilities thus provide a feasible way to tune the functions of DFNLC-based optical devices.展开更多
A set of coupled wave equations of acoustooptic diffraction with multiple acoustic waves along different directions is put forward and its solutions are derived. The characteristics of the diffraction efficiency, com ...A set of coupled wave equations of acoustooptic diffraction with multiple acoustic waves along different directions is put forward and its solutions are derived. The characteristics of the diffraction efficiency, com -pression, cross modulation, and intermodulation intensities are analyzed theoretically. The theoretical results are supported by experimental measurements through our new multiple directional acoustooptic devices.展开更多
The multi-principal element characteristic of high-entropy alloys has revolutionized the conventional alloy design concept of single-principal element,endowing them with excellent mechanical properties.However,owing t...The multi-principal element characteristic of high-entropy alloys has revolutionized the conventional alloy design concept of single-principal element,endowing them with excellent mechanical properties.However,owing to this multi-principal element nature,high-entropy alloys exhibit complex deformation behavior dominated by alternating and coupled deformation mechanisms.Therefore,elucidating these intricate deformation mechanisms remains a key challenge in current research.Neutron diffraction(ND)techniques offer distinct advantages over traditional microscopic methods for characterizing such complex deformation behavior.The strong penetration capability of neutrons enables in-situ,real-time,and non-destructive detection of structural evolution in most centimeter-level bulk samples under complex environments,and ND allows precise characterization of lattice site occupations for light elements,such as C and O,and neighboring elements.This review discussed the principles of ND,experiment procedures,and data analysis.Combining with recent advances in the research about face-centered cubic high-entropy alloy,typical examples of using ND to investigate the deformation behavior were summarized,ultimately revealing deformation mechanisms dominated by dislocations,stacking faults,twinning,and phase transformations.展开更多
Optical phase-gradient metasurfaces have garnered significant attention for enabling flexible light manipulation,with applications across diverse domains.In this work,we will demonstrate that the metasurfaces with pha...Optical phase-gradient metasurfaces have garnered significant attention for enabling flexible light manipulation,with applications across diverse domains.In this work,we will demonstrate that the metasurfaces with phase gradient modulation can be used to achieve illusion optics,featuring the advantages of simple geometric structure and feasible implementation compared with the well-known transformation optics method.The underlying mechanism is the anomalous diffraction law caused by the phase gradient,which provides a theoretical basis for freely manipulating the propagation path of light.By considering a specific example,we will demonstrate that the phase gradient can transform spatial coordinates in real space into illusion space,thereby converting a plane in real space into a curved surface structure in illusion space to achieve the illusion effect.This approach provides a viable alternative to transformation optics for designing illusion devices.展开更多
Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is c...Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is crucial for the confirmation of absolute configurations.Ignoring critical parameters will lead to false structure,which may confuse the total synthesis and drug development.Herein,the configurations of seven heterogeneous Pallavicinia diterpenoids(PDs) isolated from Pallavicinia liverworts are revised using a combination of single-crystal X-ray diffraction and electronic circular dichroism(ECD) calculations.Meanwhile,identification of five unprecedented PD heterodimers PD-dimers A-E(18-22) along with eleven previously undescribed PDs(5-9,13-17,23) obtained by the reinvestigation of the Chinese liverwort Pallavicinia subciliata have resulted in corrections and support the revised conclusions.展开更多
High-precision optical frequency measurement serves as a cornerstone of modern science and technology,enabling advancements in fields ranging from fundamental physics to quantum information technologies.Obtaining prec...High-precision optical frequency measurement serves as a cornerstone of modern science and technology,enabling advancements in fields ranging from fundamental physics to quantum information technologies.Obtaining precise photon frequencies,especially in the ultraviolet or even extreme ultraviolet regimes,is a key goal in both light–matter interaction experiments and engineering applications.High-order harmonic generation(HHG)is an ideal light source for producing such photons.In this work,we propose an optical temporal interference model(OTIM)that establishes an analogy with multi-slit Fraunhofer diffraction(MSFD)to manipulate fine-frequency photon generation by exploiting the temporal coherence of HHG processes.Our model provides a unified physical framework for three distinct non-integer HHG generation schemes:single-pulse,shaped-pulse,and laser pulse train approaches,which correspond to single-MSFD-like,double-MSFD-like,and multi-MSFD-like processes,respectively.Arbitrary non-integer HHG photons can be obtained using our scheme.Our approach provides a new perspective for accurately measuring and controlling photon frequencies in fields such as frequency comb technology,interferometry,and atomic clocks.展开更多
Chemical investigation of the marine-derived fungus Chaetomium globosum HBU-45 led to the discovery of chaeglobol A(1).Its structure was determined by spectroscopic analysis,computational electronic circular dichroism...Chemical investigation of the marine-derived fungus Chaetomium globosum HBU-45 led to the discovery of chaeglobol A(1).Its structure was determined by spectroscopic analysis,computational electronic circular dichroism(ECD)/optical rotatory dispersion(ORD)methods,and X-ray crystallography.Compound 1 represents a new skeleton with an uncommon 6/6/6/5/6/5/6/5 octacyclic system,which is presumably biosynthesized via a[4+2]cycloaddition and an enzymatic cyclization.Chaeglobol A(1)exhibited inhibitory activity against B.dothidea by destroying cell membrane integrity and causing oxidative damage within the cells.展开更多
This paper examines the effect of Fe addition on the microstructure characterized by scanning electron microscopy/electron backscattered diffraction,neutron diffraction,and synchrotron X-ray tomography and the mechani...This paper examines the effect of Fe addition on the microstructure characterized by scanning electron microscopy/electron backscattered diffraction,neutron diffraction,and synchrotron X-ray tomography and the mechanical properties of Al-Mg-Mn-Fe-Cu alloys.The findings reveal that the microstructures of the alloys consisted of an Al matrix,Al_(6)(FeMn),and Al_(2)CuMg phase particles.The addition of Fe significantly increased the yield strength(YS),and ultimate tensile strength(UTS)of the alloys,while reducing elongation.The transformation of the 3D morphology of the Al_(6)(FeMn)phase from separated and fine particles with Chinese-script morphology to interconnected rod-like structure as Fe content increased from 0.1%to 0.8%.This strengthening effect was attributed to the slip lines being blocked at the vicinity of the inter-connected Fe-rich phase,leading to grain rotation and dislocation density increment around the Fe-rich phase,ultimately improving the strength of the alloys.However,the Fe-rich phases and Al_(2)CuMg phases were found to be prone to cracking under tensile stress,resulting in decreased elongation of the alloys.This study provides a potential application in the design and manufacturing of new non-heat-treatable Al alloys for the automotive industry.展开更多
Two novel out-of-plane ordered quaternary borides M'_(4)VSiB_(2) (M'=Nb and Mo) have been synthesized. The out-of-plane ordered characteristic has been confirmed by the X-ray diffraction, the neutron powder di...Two novel out-of-plane ordered quaternary borides M'_(4)VSiB_(2) (M'=Nb and Mo) have been synthesized. The out-of-plane ordered characteristic has been confirmed by the X-ray diffraction, the neutron powder diffraction and the scanning transmission electron microscopy with high-angle angular dark field images. By adjusting the stoichiometric ratio of Mo and V, the 16l site preferentially occupied by relatively larger atom and 4c site by relatively smaller atom have been confirmed. The further first-principle calculation demonstrates the dynamical and thermodynamical stability of Mo_(4)VSiB_(2) o-T2 phase. This work confirms the transition metal occupation strategy of o-T2 phase and enriches the out-of-plane ordered laminated borides family.展开更多
Gas hydrate(GH)is an unconventional resource estimated at 1000-120,000 trillion m^(3)worldwide.Research on GH is ongoing to determine its geological and flow characteristics for commercial produc-tion.After two large-...Gas hydrate(GH)is an unconventional resource estimated at 1000-120,000 trillion m^(3)worldwide.Research on GH is ongoing to determine its geological and flow characteristics for commercial produc-tion.After two large-scale drilling expeditions to study the GH-bearing zone in the Ulleung Basin,the mineral composition of 488 sediment samples was analyzed using X-ray diffraction(XRD).Because the analysis is costly and dependent on experts,a machine learning model was developed to predict the mineral composition using XRD intensity profiles as input data.However,the model’s performance was limited because of improper preprocessing of the intensity profile.Because preprocessing was applied to each feature,the intensity trend was not preserved even though this factor is the most important when analyzing mineral composition.In this study,the profile was preprocessed for each sample using min-max scaling because relative intensity is critical for mineral analysis.For 49 test data among the 488 data,the convolutional neural network(CNN)model improved the average absolute error and coefficient of determination by 41%and 46%,respectively,than those of CNN model with feature-based pre-processing.This study confirms that combining preprocessing for each sample with CNN is the most efficient approach for analyzing XRD data.The developed model can be used for the compositional analysis of sediment samples from the Ulleung Basin and the Korea Plateau.In addition,the overall procedure can be applied to any XRD data of sediments worldwide.展开更多
Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However...Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However,chromatic aberration remains a serious longstanding problem for diffractive optics,hindering their broader adoption.To overcome the chromatic aberrations for red,green and blue(RGB)light sources,in this paper,we propose a counterintuitive multi-twist structure to achieve narrowband PBOEs without crosstalk,which plays a vital role to eliminate the chromatic aberration.The performance of our designed and fabricated narrowband Pacharatnam-Berry lenses(PBLs)aligns well with our simulation results.Furthermore,in a feasibility demonstration experiment using a laser projector,our proposed PBL system indeed exhibits a diminished chromatic aberration as compared to a broadband PBL.Additionally,polarization raytracing is implemented to demonstrate the versatility of the multi-twist structure for designing any RGB wavelengths with high contrast ratios.This analysis explores the feasibility of using RGB laser lines and quantum dot light-emitting diodes.Overall,our approach enables high optical efficiency,low fabrication complexity,and high degree of design freedom to accommodate any liquid crystal material and RGB light sources,holding immense potential for widespread applications of achromatic PBOEs.展开更多
The lattice parameter,measured with sufficient accuracy,can be utilized to evaluate the quality of single crystals and to determine the equation of state for materials.We propose an iterative method for obtaining more...The lattice parameter,measured with sufficient accuracy,can be utilized to evaluate the quality of single crystals and to determine the equation of state for materials.We propose an iterative method for obtaining more precise lattice parameters using the interaction points for the pseudo-Kossel pattern obtained from laser-induced X-ray diffraction(XRD).This method has been validated by the analysis of an XRD experiment conducted on iron single crystals.Furthermore,the method was used to calculate the compression ratio and rotated angle of an LiF sample under high pressure loading.This technique provides a robust tool for in-situ characterization of structural changes in single crystals under extreme conditions.It has significant implications for studying the equation of state and phase transitions.展开更多
Inspired by the X(4140)structure reported in the J/ψφsystem by the CDF experiment in 2009,a series of searches have been carried out in theJ/ψφand J/ψK channels,leading to the claim of ten structures in the B→J...Inspired by the X(4140)structure reported in the J/ψφsystem by the CDF experiment in 2009,a series of searches have been carried out in theJ/ψφand J/ψK channels,leading to the claim of ten structures in the B→J/ψφK system.This article provides a comprehensive review of experimental developments,from the initial evidence of X(4140)at CDF to the amplitude analyses and diffractive process investigations by the LHCb experiment,as well as theoretical interpretations of these states.A triplet of J^(PC)=1++states with relatively large mass splittings[about 200MeV(natural units are adopted)]has been identified in the J/ψφsystem by LHCb.Their mass-squared values align approximately linearly with a possible radial quantum number,suggesting that the triplet may represent a radially excited family.For X(4140),the first state in the triplet,its width reported by LHCb is inconsistent with that measured by other experiments,and possible reasons for this discrepancy are discussed.A potential connection between an excess at 4.35 GeV in the J/ψφmass spectrum reported by the Belle experiment through a two-photon process and a potential spin-2 excess in the LHCb data is also investigated.In addition,potential parallels between the J/ψφand J/ψJ/ψsystems,both composed of two vector mesons,are discussed.The continued interest in,and complexity of,these systems underscore the necessity of further experimental exploration with increased statistical precision across a variety of experiments,particularly those with relatively flat efficiency across the Dalitz plot.The J/ψω,φφ,ρω,andρφsystems are mentioned,and the prospects for the J/ψγandγγsystems,are also highlighted.展开更多
We present a theoretical scheme to realize two-dimensional(2D)asymmetric diffraction grating in a five-level inverted Y-type asymmetric double semiconductor quantum wells(SQWs)structure with resonant tunneling.The SQW...We present a theoretical scheme to realize two-dimensional(2D)asymmetric diffraction grating in a five-level inverted Y-type asymmetric double semiconductor quantum wells(SQWs)structure with resonant tunneling.The SQW structure interacts with a weak probe laser field,a spatially independent 2D standing-wave(SW)field,and a Laguerre–Gaussian(LG)vortex field,respectively.The results indicate that the diffraction patterns are highly sensitive to amplitude modulation and phase modulation.Because of the existence of vortex light,it is possible to realize asymmetric high-order diffraction in the SQW structure,and then a 2D asymmetric grating is established.By adjusting the detunings of the probe field,vortex field,and SW field,as well as the interaction length,diffraction intensity,and direction of the 2D asymmetric electromagnetically induced grating(EIG)can be controlled effectively.In addition,the number of orbital angular momenta(OAM)and beam waist parameter can be used to modulate the diffraction intensity and energy transfer of the probe light in different regions.High-order diffraction intensity is enhanced and high-efficiency 2D asymmetric diffraction grating with different diffraction patterns is obtained in the scheme.Such 2D asymmetric diffraction grating may be beneficial to the research of optical communication and innovative semiconductor quantum devices.展开更多
Employing experimental equipment and techniques,such as electron backscatter diffraction,transmission Kikuchi diffraction,and transmission electron microscopy,the microstructure,phase structure,and orientation relatio...Employing experimental equipment and techniques,such as electron backscatter diffraction,transmission Kikuchi diffraction,and transmission electron microscopy,the microstructure,phase structure,and orientation relationships of 0.6μm electroplated nickel(Ni)steel following annealing at 580-650℃for 15-30 hours were investigated.A comprehensive analysis was conducted to gain insights into the complex changes in the material's properties due to the annealing process.The results reveal that prolonged annealing led to considerable long-range diffusion of surface Ni atoms into the substrate of the 0.6μm Ni-plated steel.This diffusion process resulted in the formation of an alloy diffusion layer,approximately 4μm in thickness,which altered the material's microstructural characteristics.The extent of diffusion and its effect on the microstructure and structure were meticulously quantified.At the annealing temperature,the diffused Ni in the substrate,acting as an austenite-stabilizing element,expanded the austenite phase region.The alloy layer at this temperature predominantly consisted of the face-centered cubic(FCC)-structuredγ(Fe,Ni)solid solution.Upon cooling to room temperature,the alloy diffusion layer evolved into a dual-layer composite structure.The upper layer mainly comprised the FCC-structuredγ(Fe,Ni)solid solution,interspersed with a minor FCC compound superstructure phase.The lower layer underwent a diffusionless phase transformation during cooling,which led to the formation of the body-centered tetragonal/body-centered cubic-structured martensite.This phase,which is known for its high hardness and numerous variants,maintained the classic Kurdjumov-Sachs orientation relationship with the upper FCC parent phase,and it satisfied the close-packed plane{111}γ//{110}α′and close-packed direction<110>γ//<111>α′.A detailed analysis of the different phases within the alloy layer and their phase transitions was presented,offering an in-depth understanding of the material's characteristics.展开更多
In oil and gas exploration,small-scale karst cavities and faults are important targets.The former often serve as reservoir space for carbonate reservoirs,while the latter often provide migration pathways for oil and g...In oil and gas exploration,small-scale karst cavities and faults are important targets.The former often serve as reservoir space for carbonate reservoirs,while the latter often provide migration pathways for oil and gas.Due to these differences,the classification and identification of karst cavities and faults are of great significance for reservoir development.Traditional seismic attributes and diffraction imaging techniques can effectively identify discontinuities in seismic images,but these techniques do not distinguish whether these discontinuities are karst cavities,faults,or other structures.It poses a challenge for seismic interpretation to accurately locate and classify karst cavities or faults within the seismic attribute maps and diffraction imaging profiles.In seismic data,the scattering waves are associated with small-scale scatters like karst cavities,while diffracted waves are seismic responses from discontinuous structures such as faults,reflector edges and fractures.In order to achieve classification and identification of small-scale karst cavities and faults in seismic images,we propose a diffraction classification imaging method which classifies diffracted and scattered waves in the azimuth-dip angle image matrix using a modified DenseNet.We introduce a coordinate attention module into DenseNet,enabling more precise extraction of dynamic and azimuthal features of diffracted and scattered waves in the azimuth-dip angle image matrix.Leveraging these extracted features,the modified DenseNet can produce reliable probabilities for diffracted/scattered waves,achieving high-accuracy automatic classification of cavities and faults based on diffraction imaging.The proposed method achieves 96%classification accuracy on the synthetic dataset.The field data experiment demonstrates that the proposed method can accurately classify small-scale faults and scatterers,further enhancing the resolution of diffraction imaging in complex geologic structures,and contributing to the localization of karstic fracture-cavern reservoirs.展开更多
The precise control of wrinkles and strain gradients in nanofilm is of significant interest due to their profound influence on electronic band structures and spin states.Here,we employ ultrafast electron diffraction(U...The precise control of wrinkles and strain gradients in nanofilm is of significant interest due to their profound influence on electronic band structures and spin states.Here,we employ ultrafast electron diffraction(UED)to study the picosecond-scale dynamics of laser-induced bending in 2H-MoTe2 thin films.展开更多
The release of essential nutrients from soil minerals for plant growth in calcareous soils,facilitated by organic extractants,is critical in semi-arid areas,particularly for elements affected by high soil pH.This stud...The release of essential nutrients from soil minerals for plant growth in calcareous soils,facilitated by organic extractants,is critical in semi-arid areas,particularly for elements affected by high soil pH.This study aims to investigate the release of calcium(Ca),magnesium(Mg),and phosphorus(P)through the application of wood vinegar extract in surface calcareous soils in Borojerd City,Lorestan Province,Iran.The experiment was conducted using a completely randomized design with three replications.The treatments included soils from three different land uses:vineyard,wheat field,and rangeland,each treated with 1.00%wood vinegar solution.Cumulative measurements of the specified elements were recorded over 10 consecutive 0.5 h intervals.The release data were analyzed using four various kinetic models(Elovich equation,parabolic diffusion law,power function equation,and zero-order kinetics).The highest concentrations recorded were for Ca(39,500.00 mg/kg),Mg(5880.00 mg/kg),and P(5.00 mg/kg)in grape cultivation.The findings revealed a significant difference in Ca release between grape cultivation and rangeland(P<0.01),while the Mg release showed a significant difference between both grape cultivation and rangeland and wheat cultivation(P<0.01).Additionally,the cumulative release of P showed significant differences between grape cultivation and both wheat and rangeland(P<0.01).The results indicated that the zero-order kinetics provided the best fit for the data(R^(2)=0.99).The maximum initial release amount was observed in grape cultivation when applying the zero-order kinetics,while the highest release rate was achieved using the parabolic diffusion law across three applications.Wood vinegar had the capacity to degrade various clay minerals,including vermiculite,smectite,palygorskite,and,to some extent,illite,resulting in the release of associated elements.Consequently,it can be concluded that wood vinegar can be effectively utilized in grape cultivation as an agent for reducing soil acidity,thereby enhancing the availability of soil nutrients and decreasing reliance on chemical fertilizers.展开更多
基金funded jointly by the National Natural Science Foundation of China(No.41104069)Shandong Province Higher Educational Science and Technology Program(No.J17KA197)+1 种基金Open Foundation of Shandong Provincial Key Laboratory of Depositional Mineralization&Sedimentary Minerals of Shandong University of Science and Technology(No.DMSM2018018)Chunhui Research Foundation of Shengli College,China University of Petroleum(No.KY2017007)。
文摘Fracture-cave reservoirs in carbonate rocks are characterized by a large difference in fracture and cavity size,and a sharp variation in lithology and velocity,thereby resulting in complex diffraction responses.Some small-scale fractures and caves cause weak diffraction energy and would be obscured by the continuous reflection layer in the imaging section,thereby making them difficult to identify.This paper develops a diffraction wave imaging method in the dip domain,which can improve the resolution of small-scale diffractors in the imaging section.Common imaging gathers(CIGs)in the dip domain are extracted by Gaussian beam migration.In accordance with the geometric differences of the diffraction being quasilinear and the reflection being quasiparabolic in the dip-domain CIGs,we use slope analysis technique to filter waves and use Hanning window function to improve the diffraction wave separation level.The diffraction dip-domain CIGs are stacked horizontally to obtain diffraction imaging results.Wavefield separation analysis and numerical modeling results show that the slope analysis method,together with Hanning window filtering,can better suppress noise to obtain the diffraction dip-domain CIGs,thereby improving the clarity of the diffractors in the diffraction imaging section.
基金Supported by the Higher School Visiting Scholar Development Project under Grant No.FX2013103the Research Fund under Grant No.ZCI2XJY003+2 种基金 Research Fund for the Doctoral Program under Grant No.Z301B13519 of the Zhejiang University of Media and CommunicationsZhejiang Province Science Foundation for Youths under Grant No.LQ12F05005National Natural Science Foundation of China under Grant No.11374254
文摘We discuss the nonlinear Schr6dinger equation with variable coefficients in 21） graded-index waveguides with different distributed transverse diffractions and obtain exact bright and dark soliton solutions. Based on these solutions, we mainly investigate the dynamical behaviors of solitons in three different diffraction decreasing waveguides with the hyperbolic, Gaussian and Logarithmic profiles. Results indicate that for the same parameters, the amplitude of bright solitons in the Logarithmic profile and the amplitude of dark solitons in the Gaussian profile are biggest respectively, and the amplitude in the hyperbolic profile is smallest, while the width of solitons has the opposite case.
基金supported by the National Key Research and Development Program of China(No.2021YFA1202000)National Natural Science Foundation of China(Nos.52003115 and RK106LH21001)Natural Science Foundation of Jiangsu Province(Nos.BK20212004 and BK20200320).
文摘Electrically driven structural patterns in liquid crystals(LCs)have attracted considerable attention due to their electrooptical applications.Here,we disclose various appealing reconfigurable LC microstructures in a dual frequency nematic LC(DFNLC)owing to the electroconvection-induced distortion of the LC director,including one-dimensional rolls,chevron pattern,two-dimensional grids,and unstable chaos.These patterns can be switched among each other,and the lattice constants are modulated by tuning the amplitude and frequency of the applied electric field.The electrically switchable self-assembled microstructures and their beam steering capabilities thus provide a feasible way to tune the functions of DFNLC-based optical devices.
基金The project is supported by National Natural Science Foundation of China.
文摘A set of coupled wave equations of acoustooptic diffraction with multiple acoustic waves along different directions is put forward and its solutions are derived. The characteristics of the diffraction efficiency, com -pression, cross modulation, and intermodulation intensities are analyzed theoretically. The theoretical results are supported by experimental measurements through our new multiple directional acoustooptic devices.
基金National Key R&D Program of China(2023YFB3711904,2022YFA1603801)National Natural Science Foundation of China(12404230,52471181,52301213,52130108,52471005)+2 种基金National Nature Science Foundation of Zhejiang Province(LY23E010002)Open Fund of the China Spallation Neutron Source,Songshan Lake Science City(KFKT2023B11)Guangdong Basic and Applied Basic Research Foundation(2022A1515110805,2024A1515010878)。
文摘The multi-principal element characteristic of high-entropy alloys has revolutionized the conventional alloy design concept of single-principal element,endowing them with excellent mechanical properties.However,owing to this multi-principal element nature,high-entropy alloys exhibit complex deformation behavior dominated by alternating and coupled deformation mechanisms.Therefore,elucidating these intricate deformation mechanisms remains a key challenge in current research.Neutron diffraction(ND)techniques offer distinct advantages over traditional microscopic methods for characterizing such complex deformation behavior.The strong penetration capability of neutrons enables in-situ,real-time,and non-destructive detection of structural evolution in most centimeter-level bulk samples under complex environments,and ND allows precise characterization of lattice site occupations for light elements,such as C and O,and neighboring elements.This review discussed the principles of ND,experiment procedures,and data analysis.Combining with recent advances in the research about face-centered cubic high-entropy alloy,typical examples of using ND to investigate the deformation behavior were summarized,ultimately revealing deformation mechanisms dominated by dislocations,stacking faults,twinning,and phase transformations.
基金supported by the National Natural Science Foundation of China (Grant Nos.12274313 and 62375234)the Gusu Leading Talent Plan for Scientific and Technological Innovation and Entrepreneurship (Grant No.ZXL2024400)。
文摘Optical phase-gradient metasurfaces have garnered significant attention for enabling flexible light manipulation,with applications across diverse domains.In this work,we will demonstrate that the metasurfaces with phase gradient modulation can be used to achieve illusion optics,featuring the advantages of simple geometric structure and feasible implementation compared with the well-known transformation optics method.The underlying mechanism is the anomalous diffraction law caused by the phase gradient,which provides a theoretical basis for freely manipulating the propagation path of light.By considering a specific example,we will demonstrate that the phase gradient can transform spatial coordinates in real space into illusion space,thereby converting a plane in real space into a curved surface structure in illusion space to achieve the illusion effect.This approach provides a viable alternative to transformation optics for designing illusion devices.
基金supported by the National Natural Science Foundation of China (Nos.82293682,82293684,and 82173703)。
文摘Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is crucial for the confirmation of absolute configurations.Ignoring critical parameters will lead to false structure,which may confuse the total synthesis and drug development.Herein,the configurations of seven heterogeneous Pallavicinia diterpenoids(PDs) isolated from Pallavicinia liverworts are revised using a combination of single-crystal X-ray diffraction and electronic circular dichroism(ECD) calculations.Meanwhile,identification of five unprecedented PD heterodimers PD-dimers A-E(18-22) along with eleven previously undescribed PDs(5-9,13-17,23) obtained by the reinvestigation of the Chinese liverwort Pallavicinia subciliata have resulted in corrections and support the revised conclusions.
基金supported by the National Natural Science Foundation of China(Grant No.12304379)the Natural Science Foundation of Liaoning Province(Grant No.2024BS-269)the Guangdong Basic and Applied Basic Research Foundation(Grant No.025A1515011117)。
文摘High-precision optical frequency measurement serves as a cornerstone of modern science and technology,enabling advancements in fields ranging from fundamental physics to quantum information technologies.Obtaining precise photon frequencies,especially in the ultraviolet or even extreme ultraviolet regimes,is a key goal in both light–matter interaction experiments and engineering applications.High-order harmonic generation(HHG)is an ideal light source for producing such photons.In this work,we propose an optical temporal interference model(OTIM)that establishes an analogy with multi-slit Fraunhofer diffraction(MSFD)to manipulate fine-frequency photon generation by exploiting the temporal coherence of HHG processes.Our model provides a unified physical framework for three distinct non-integer HHG generation schemes:single-pulse,shaped-pulse,and laser pulse train approaches,which correspond to single-MSFD-like,double-MSFD-like,and multi-MSFD-like processes,respectively.Arbitrary non-integer HHG photons can be obtained using our scheme.Our approach provides a new perspective for accurately measuring and controlling photon frequencies in fields such as frequency comb technology,interferometry,and atomic clocks.
基金funded by the S&T Program of Hebei(No.21323202D)the Natural Science Interdisciplinary Research Program of Hebei University(No.DXK201913)+4 种基金the Natural Sci-ence Foundation of Hebei Province of China(Nos.H2024201028,H2020201029)the Excellent Youth Research Innovation Team of Hebei University(No.QNTD202406)the Hebei University Research and Innovation Team(No.IT2023C1)the Innovation Capacity Improvement Plan of Hebei Province(No.20567605H)the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.DC2024177)。
文摘Chemical investigation of the marine-derived fungus Chaetomium globosum HBU-45 led to the discovery of chaeglobol A(1).Its structure was determined by spectroscopic analysis,computational electronic circular dichroism(ECD)/optical rotatory dispersion(ORD)methods,and X-ray crystallography.Compound 1 represents a new skeleton with an uncommon 6/6/6/5/6/5/6/5 octacyclic system,which is presumably biosynthesized via a[4+2]cycloaddition and an enzymatic cyclization.Chaeglobol A(1)exhibited inhibitory activity against B.dothidea by destroying cell membrane integrity and causing oxidative damage within the cells.
基金support from the Natural Science Foundation of China(Nos.52104373,52074131,and 51974092)the Basic and Applied Basic Foundation of Guangdong Province(No.2020B1515120065)。
文摘This paper examines the effect of Fe addition on the microstructure characterized by scanning electron microscopy/electron backscattered diffraction,neutron diffraction,and synchrotron X-ray tomography and the mechanical properties of Al-Mg-Mn-Fe-Cu alloys.The findings reveal that the microstructures of the alloys consisted of an Al matrix,Al_(6)(FeMn),and Al_(2)CuMg phase particles.The addition of Fe significantly increased the yield strength(YS),and ultimate tensile strength(UTS)of the alloys,while reducing elongation.The transformation of the 3D morphology of the Al_(6)(FeMn)phase from separated and fine particles with Chinese-script morphology to interconnected rod-like structure as Fe content increased from 0.1%to 0.8%.This strengthening effect was attributed to the slip lines being blocked at the vicinity of the inter-connected Fe-rich phase,leading to grain rotation and dislocation density increment around the Fe-rich phase,ultimately improving the strength of the alloys.However,the Fe-rich phases and Al_(2)CuMg phases were found to be prone to cracking under tensile stress,resulting in decreased elongation of the alloys.This study provides a potential application in the design and manufacturing of new non-heat-treatable Al alloys for the automotive industry.
基金supported by the National Youth Talent Support Program(No.QNBJ-2022-03)the National Natu-ral Science Foundation of China(No.52371180)the Fundamental Research Funds for the Central Universities(Nos.N2209005 and N2309001).
文摘Two novel out-of-plane ordered quaternary borides M'_(4)VSiB_(2) (M'=Nb and Mo) have been synthesized. The out-of-plane ordered characteristic has been confirmed by the X-ray diffraction, the neutron powder diffraction and the scanning transmission electron microscopy with high-angle angular dark field images. By adjusting the stoichiometric ratio of Mo and V, the 16l site preferentially occupied by relatively larger atom and 4c site by relatively smaller atom have been confirmed. The further first-principle calculation demonstrates the dynamical and thermodynamical stability of Mo_(4)VSiB_(2) o-T2 phase. This work confirms the transition metal occupation strategy of o-T2 phase and enriches the out-of-plane ordered laminated borides family.
基金supported by the Gas Hydrate R&D Organization and the Korea Institute of Geoscience and Mineral Resources(KIGAM)(GP2021-010)supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.2021R1C1C1004460)Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Korean government(MOTIE)(20214000000500,Training Program of CCUS for Green Growth).
文摘Gas hydrate(GH)is an unconventional resource estimated at 1000-120,000 trillion m^(3)worldwide.Research on GH is ongoing to determine its geological and flow characteristics for commercial produc-tion.After two large-scale drilling expeditions to study the GH-bearing zone in the Ulleung Basin,the mineral composition of 488 sediment samples was analyzed using X-ray diffraction(XRD).Because the analysis is costly and dependent on experts,a machine learning model was developed to predict the mineral composition using XRD intensity profiles as input data.However,the model’s performance was limited because of improper preprocessing of the intensity profile.Because preprocessing was applied to each feature,the intensity trend was not preserved even though this factor is the most important when analyzing mineral composition.In this study,the profile was preprocessed for each sample using min-max scaling because relative intensity is critical for mineral analysis.For 49 test data among the 488 data,the convolutional neural network(CNN)model improved the average absolute error and coefficient of determination by 41%and 46%,respectively,than those of CNN model with feature-based pre-processing.This study confirms that combining preprocessing for each sample with CNN is the most efficient approach for analyzing XRD data.The developed model can be used for the compositional analysis of sediment samples from the Ulleung Basin and the Korea Plateau.In addition,the overall procedure can be applied to any XRD data of sediments worldwide.
基金supports from the National Key Research and Development Program of China(2023YFB2806803)the National Natural Science Foundation of China(62075127).
文摘Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However,chromatic aberration remains a serious longstanding problem for diffractive optics,hindering their broader adoption.To overcome the chromatic aberrations for red,green and blue(RGB)light sources,in this paper,we propose a counterintuitive multi-twist structure to achieve narrowband PBOEs without crosstalk,which plays a vital role to eliminate the chromatic aberration.The performance of our designed and fabricated narrowband Pacharatnam-Berry lenses(PBLs)aligns well with our simulation results.Furthermore,in a feasibility demonstration experiment using a laser projector,our proposed PBL system indeed exhibits a diminished chromatic aberration as compared to a broadband PBL.Additionally,polarization raytracing is implemented to demonstrate the versatility of the multi-twist structure for designing any RGB wavelengths with high contrast ratios.This analysis explores the feasibility of using RGB laser lines and quantum dot light-emitting diodes.Overall,our approach enables high optical efficiency,low fabrication complexity,and high degree of design freedom to accommodate any liquid crystal material and RGB light sources,holding immense potential for widespread applications of achromatic PBOEs.
基金National Natural Science Foundation of China(12102410)Fund of National Key Laboratory of Shock Wave and Detonation Physics(JCKYS2022212005)。
文摘The lattice parameter,measured with sufficient accuracy,can be utilized to evaluate the quality of single crystals and to determine the equation of state for materials.We propose an iterative method for obtaining more precise lattice parameters using the interaction points for the pseudo-Kossel pattern obtained from laser-induced X-ray diffraction(XRD).This method has been validated by the analysis of an XRD experiment conducted on iron single crystals.Furthermore,the method was used to calculate the compression ratio and rotated angle of an LiF sample under high pressure loading.This technique provides a robust tool for in-situ characterization of structural changes in single crystals under extreme conditions.It has significant implications for studying the equation of state and phase transitions.
基金partially supported by the Natural Science Foundation of China(Grant Nos.12075123,12061141002,and 12535004)the Ministry of Science and Technology of China(Grant Nos.2023YFA1605804 and 2024YFA1610501)。
文摘Inspired by the X(4140)structure reported in the J/ψφsystem by the CDF experiment in 2009,a series of searches have been carried out in theJ/ψφand J/ψK channels,leading to the claim of ten structures in the B→J/ψφK system.This article provides a comprehensive review of experimental developments,from the initial evidence of X(4140)at CDF to the amplitude analyses and diffractive process investigations by the LHCb experiment,as well as theoretical interpretations of these states.A triplet of J^(PC)=1++states with relatively large mass splittings[about 200MeV(natural units are adopted)]has been identified in the J/ψφsystem by LHCb.Their mass-squared values align approximately linearly with a possible radial quantum number,suggesting that the triplet may represent a radially excited family.For X(4140),the first state in the triplet,its width reported by LHCb is inconsistent with that measured by other experiments,and possible reasons for this discrepancy are discussed.A potential connection between an excess at 4.35 GeV in the J/ψφmass spectrum reported by the Belle experiment through a two-photon process and a potential spin-2 excess in the LHCb data is also investigated.In addition,potential parallels between the J/ψφand J/ψJ/ψsystems,both composed of two vector mesons,are discussed.The continued interest in,and complexity of,these systems underscore the necessity of further experimental exploration with increased statistical precision across a variety of experiments,particularly those with relatively flat efficiency across the Dalitz plot.The J/ψω,φφ,ρω,andρφsystems are mentioned,and the prospects for the J/ψγandγγsystems,are also highlighted.
基金supported by the National Natural Science Foundation of China(Grant No.12105210)the Knowledge Innovation Program of Wuhan-Basi Research(Grant No.2023010201010149)。
文摘We present a theoretical scheme to realize two-dimensional(2D)asymmetric diffraction grating in a five-level inverted Y-type asymmetric double semiconductor quantum wells(SQWs)structure with resonant tunneling.The SQW structure interacts with a weak probe laser field,a spatially independent 2D standing-wave(SW)field,and a Laguerre–Gaussian(LG)vortex field,respectively.The results indicate that the diffraction patterns are highly sensitive to amplitude modulation and phase modulation.Because of the existence of vortex light,it is possible to realize asymmetric high-order diffraction in the SQW structure,and then a 2D asymmetric grating is established.By adjusting the detunings of the probe field,vortex field,and SW field,as well as the interaction length,diffraction intensity,and direction of the 2D asymmetric electromagnetically induced grating(EIG)can be controlled effectively.In addition,the number of orbital angular momenta(OAM)and beam waist parameter can be used to modulate the diffraction intensity and energy transfer of the probe light in different regions.High-order diffraction intensity is enhanced and high-efficiency 2D asymmetric diffraction grating with different diffraction patterns is obtained in the scheme.Such 2D asymmetric diffraction grating may be beneficial to the research of optical communication and innovative semiconductor quantum devices.
文摘Employing experimental equipment and techniques,such as electron backscatter diffraction,transmission Kikuchi diffraction,and transmission electron microscopy,the microstructure,phase structure,and orientation relationships of 0.6μm electroplated nickel(Ni)steel following annealing at 580-650℃for 15-30 hours were investigated.A comprehensive analysis was conducted to gain insights into the complex changes in the material's properties due to the annealing process.The results reveal that prolonged annealing led to considerable long-range diffusion of surface Ni atoms into the substrate of the 0.6μm Ni-plated steel.This diffusion process resulted in the formation of an alloy diffusion layer,approximately 4μm in thickness,which altered the material's microstructural characteristics.The extent of diffusion and its effect on the microstructure and structure were meticulously quantified.At the annealing temperature,the diffused Ni in the substrate,acting as an austenite-stabilizing element,expanded the austenite phase region.The alloy layer at this temperature predominantly consisted of the face-centered cubic(FCC)-structuredγ(Fe,Ni)solid solution.Upon cooling to room temperature,the alloy diffusion layer evolved into a dual-layer composite structure.The upper layer mainly comprised the FCC-structuredγ(Fe,Ni)solid solution,interspersed with a minor FCC compound superstructure phase.The lower layer underwent a diffusionless phase transformation during cooling,which led to the formation of the body-centered tetragonal/body-centered cubic-structured martensite.This phase,which is known for its high hardness and numerous variants,maintained the classic Kurdjumov-Sachs orientation relationship with the upper FCC parent phase,and it satisfied the close-packed plane{111}γ//{110}α′and close-packed direction<110>γ//<111>α′.A detailed analysis of the different phases within the alloy layer and their phase transitions was presented,offering an in-depth understanding of the material's characteristics.
基金supported by Science Fund for Creative Research Groups of the National Natural Science Foundation of China,No.42321002。
文摘In oil and gas exploration,small-scale karst cavities and faults are important targets.The former often serve as reservoir space for carbonate reservoirs,while the latter often provide migration pathways for oil and gas.Due to these differences,the classification and identification of karst cavities and faults are of great significance for reservoir development.Traditional seismic attributes and diffraction imaging techniques can effectively identify discontinuities in seismic images,but these techniques do not distinguish whether these discontinuities are karst cavities,faults,or other structures.It poses a challenge for seismic interpretation to accurately locate and classify karst cavities or faults within the seismic attribute maps and diffraction imaging profiles.In seismic data,the scattering waves are associated with small-scale scatters like karst cavities,while diffracted waves are seismic responses from discontinuous structures such as faults,reflector edges and fractures.In order to achieve classification and identification of small-scale karst cavities and faults in seismic images,we propose a diffraction classification imaging method which classifies diffracted and scattered waves in the azimuth-dip angle image matrix using a modified DenseNet.We introduce a coordinate attention module into DenseNet,enabling more precise extraction of dynamic and azimuthal features of diffracted and scattered waves in the azimuth-dip angle image matrix.Leveraging these extracted features,the modified DenseNet can produce reliable probabilities for diffracted/scattered waves,achieving high-accuracy automatic classification of cavities and faults based on diffraction imaging.The proposed method achieves 96%classification accuracy on the synthetic dataset.The field data experiment demonstrates that the proposed method can accurately classify small-scale faults and scatterers,further enhancing the resolution of diffraction imaging in complex geologic structures,and contributing to the localization of karstic fracture-cavern reservoirs.
基金supported by the High-level Talent Research Start-up Project Funding of Henan Academy of Sciences(Project No.241827012)the National Natural Science Foundation of China(Grant Nos.U22A6005 and 62271450)+1 种基金the National Key Research and Development Program of China(Grant Nos.2021YFA1301502,2024YFA1408701,and 2024YFA1408403)the Synergetic Extreme Condition User Facility(SECUF,https://cstr.cn/31123.02.SECUF)。
文摘The precise control of wrinkles and strain gradients in nanofilm is of significant interest due to their profound influence on electronic band structures and spin states.Here,we employ ultrafast electron diffraction(UED)to study the picosecond-scale dynamics of laser-induced bending in 2H-MoTe2 thin films.
文摘The release of essential nutrients from soil minerals for plant growth in calcareous soils,facilitated by organic extractants,is critical in semi-arid areas,particularly for elements affected by high soil pH.This study aims to investigate the release of calcium(Ca),magnesium(Mg),and phosphorus(P)through the application of wood vinegar extract in surface calcareous soils in Borojerd City,Lorestan Province,Iran.The experiment was conducted using a completely randomized design with three replications.The treatments included soils from three different land uses:vineyard,wheat field,and rangeland,each treated with 1.00%wood vinegar solution.Cumulative measurements of the specified elements were recorded over 10 consecutive 0.5 h intervals.The release data were analyzed using four various kinetic models(Elovich equation,parabolic diffusion law,power function equation,and zero-order kinetics).The highest concentrations recorded were for Ca(39,500.00 mg/kg),Mg(5880.00 mg/kg),and P(5.00 mg/kg)in grape cultivation.The findings revealed a significant difference in Ca release between grape cultivation and rangeland(P<0.01),while the Mg release showed a significant difference between both grape cultivation and rangeland and wheat cultivation(P<0.01).Additionally,the cumulative release of P showed significant differences between grape cultivation and both wheat and rangeland(P<0.01).The results indicated that the zero-order kinetics provided the best fit for the data(R^(2)=0.99).The maximum initial release amount was observed in grape cultivation when applying the zero-order kinetics,while the highest release rate was achieved using the parabolic diffusion law across three applications.Wood vinegar had the capacity to degrade various clay minerals,including vermiculite,smectite,palygorskite,and,to some extent,illite,resulting in the release of associated elements.Consequently,it can be concluded that wood vinegar can be effectively utilized in grape cultivation as an agent for reducing soil acidity,thereby enhancing the availability of soil nutrients and decreasing reliance on chemical fertilizers.
