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Tailoring electron vortex beams with customizable intensity patterns by electron diffraction holography

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Opto-Electronic Advances 2024年第2期7卷 14-21页

作者： Pengcheng Huo Ruixuan Yu Mingze Liu Hui Zhang Yan-qing Lu Ting xu National Laboratory of Solid-State Microstructures and Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China College of Engineering and Applied Sciences Key Laboratory of Intelligent Optical Sensing and Manipulation and Jiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjing 210093China

An electron vortex beam(EVB) carrying orbital angular momentum(OAM) plays a key role in a series of fundamental scientific researches, such as chiral energy-loss spectroscopy and magnetic dichroism spectroscopy. So far, almost all the experimentally created EVBs manifest isotropic doughnut intensity patterns. Here, based on the correlation between local divergence angle of electron beam and phase gradient along azimuthal direction, we show that free electrons can be tailored to EVBs with customizable intensity patterns independent of the carried OAM. As proof-of-concept, by using computer generated hologram and designing phase masks to shape the incident free electrons in the transmission electron microscope, three structured EVBs carrying identical OAM are tailored to exhibit completely different intensity patterns. Furthermore, through the modal decomposition, we quantitatively investigate their OAM spectral distributions and reveal that structured EVBs present a superposition of a series of different eigenstates induced by the locally varied geometries. These results not only generalize the concept of EVB, but also demonstrate an extra highly controllable degree of freedom for electron beam manipulation in addition to OAM.

关键词： electron vortex beam orbital angular momentum diffraction holography

Real-time arrival picking of rock microfracture signals based on convolutional-recurrent neural network and its engineering application

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 761-777页

作者： Bing-Rui Chen xu Wang Xinhao Zhu qing Wang Houlin Xie State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

Accurately picking P-and S-wave arrivals of microseismic(MS)signals in real-time directly influences the early warning of rock mass failure.A common contradiction between accuracy and computation exists in the current arrival picking ***,a real-time arrival picking method of MS signals is constructed based on a convolutional-recurrent neural network(CRNN).This method fully utilizes the advantages of convolutional layers and gated recurrent units(GRU)in extracting short-and long-term features,in order to create a precise and lightweight arrival picking ***,the synthetic signals with field noises are used to evaluate the hyperparameters of the CRNN model and obtain an optimal CRNN *** actual operation on various devices indicates that compared with the U-Net method,the CRNN method achieves faster arrival picking with less performance *** application of large underground caverns in the Yebatan hydropower station(YBT)project shows that compared with the short-term average/long-term average(STA/LTA),Akaike information criterion(AIC)and U-Net methods,the CRNN method has the highest accuracy within four sampling points,which is 87.44%for P-wave and 91.29%for S-wave,*** sum of mean absolute errors(MAESUM)of the CRNN method is 4.22 sampling points,which is lower than that of the other *** the four methods,the MS sources location calculated based on the CRNN method shows the best consistency with the actual failure,which occurs at the junction of the shaft and the second ***,the proposed method can pick up P-and S-arrival accurately and rapidly,providing a reference for rock failure analysis and evaluation in engineering applications.

关键词： Rock mass failure Microseismic event P-wave arrival S-wave arrival Deep learning

Pressure transient characteristics of non-uniform conductivity fractured wells in viscoelasticity polymer flooding based on oil-water two-phase flow

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Petroleum Science 2024年第1期21卷 343-351页

作者： Yang Wang Jia Zhang Shi-Long Yang Ze-xuan xu Shi-qing Cheng National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China

Polymer flooding in fractured wells has been extensively applied in oilfields to enhance oil *** contrast to water,polymer solution exhibits non-Newtonian and nonlinear behavior such as effects of shear thinning and shear thickening,polymer convection,diffusion,adsorption retention,inaccessible pore volume and reduced effective ***,the flux density and fracture conductivity along the hydraulic fracture are generally non-uniform due to the effects of pressure distribution,formation damage,and proppant *** this paper,we present an oil-water two-phase flow model that captures these complex non-Newtonian and nonlinear behavior,and non-uniform fracture characteristics in fractured polymer *** hydraulic fracture is firstly divided into two parts:high-conductivity fracture near the wellbore and low-conductivity fracture in the far-wellbore section.A hybrid grid system,including perpendicular bisection(PEBI)and Cartesian grid,is applied to discrete the partial differential flow equations,and the local grid refinement method is applied in the near-wellbore region to accurately calculate the pressure distribution and shear rate of polymer *** combination of polymer behavior characterizations and numerical flow simulations are applied,resulting in the calculation for the distribution of water saturation,polymer concentration and reservoir *** with the polymer flooding well with uniform fracture conductivity,this non-uniform fracture conductivity model exhibits the larger pressure difference,and the shorter bilinear flow period due to the decrease of fracture flow ability in the far-wellbore *** field case of the fall-off test demonstrates that the proposed method characterizes fracture characteristics more accurately,and yields fracture half-lengths that better match engineering reality,enabling a quantitative segmented characterization of the near-wellbore section with high fracture conductivity and th

关键词： Polymer flooding Non-Newtonian fluid Non-uniform fracture conductivity Two-phase flow Pressure transient analysis

Building Feedback-Regulation System Through Atomic Design for Highly Active SO_(2)Sensing

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Nano-Micro Letters 2024年第7期16卷 343-357页

作者： Xin Jia Panzhe Qiao Xiaowu Wang Muyu Yan Yang Chen bao-Li An Pengfei Hu Bo Lu Jing xu Zhenggang xue Jiaqiang xu NEST Lab Department of ChemistryCollege of SciencesShanghai UniversityShanghai 200444People’s Republic of China Shanghai Synchrotron Radiation Facility Zhangjiang LabShanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204People’s Republic of China School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026People’s Republic of China Key Laboratory of Organic Compound Pollution Control Engineering(MOE) School of Environmental and Chemical EngineeringShanghai UniversityShanghai 200444People’s Republic of China Shanghai University Instrumental Analysis&Research Center of Shanghai UniversityShanghai 200444People’s Republic of China

Reasonably constructing an atomic interface is pronouncedly essential for surface-related gas-sensing ***,we present an ingen-ious feedback-regulation system by changing the interactional mode between single Pt atoms and adjacent S species for high-efficiency SO_(2)*** found that the single Pt sites on the MoS_(2)surface can induce easier volatiliza-tion of adjacent S species to activate the whole inert S ***,the activated S species can provide a feedback role in tailoring the antibonding-orbital electronic occupancy state of Pt atoms,thus creating a combined system involving S vacancy-assisted single Pt sites(Pt-Vs)to synergistically improve the adsorption ability of SO_(2)gas ***-more,in situ Raman,ex situ X-ray photoelectron spectroscopy testing and density functional theory analysis demonstrate the intact feedback-regulation system can expand the electron transfer path from single Pt sites to whole Pt-MoS_(2)supports in SO_(2)gas *** with wireless-sensing modules,the final Pt1-MoS_(2)-def sensors array can further realize real-time monitoring of SO_(2)levels and cloud-data storage for plant *** a fundamental understanding of the intrinsic link between atomic interface and sensing mechanism is thus expected to broaden the rational design of highly effective gas sensors.

关键词： Feedback-regulation system Atomic interface SO_(2)sensor Single-atom sensing mechanism Intelligent-sensing array

The remarkable effect of amino hydrogen on membrane permeability and organelle staining of 1,8-naphthalimide dyes

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Chinese Chemical Letters 2024年第2期35卷 347-351页

作者： Zhifeng Li qinglong Qiao Ning xu Kai An Wenchao Jiang Yi Tao Pengjun bao Yinchan Zhang Zhaochao xu School of Chemistry Dalian University of TechnologyDalian 116024China CAS Key Laboratory of Separation Science for Analytical Chemistry Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China

Membrane permeability and intracellular diffusion of fluorescent probes determine staining selectivity of intracellular ***,the relationship between the molecular structure of fluorescent probes and their membrane permeability and intracellular distribution is poorly *** this paper,we reported a series of 1,8-naphthalimide dyes and carried out cell imaging experiments,and found that the presence of amino hydrogen in these dyes played a crucial role in their cell membrane permeability and intracellular *** secondary amino group containing compounds 1-4 show excellent membrane permeability and strong fluorescence in living *** the tertiary amine containing dyes 5 and 6 can hardly permeate the cell membrane though they show extremely similar structure with compounds *** 1 can selectively image lipid droplets by selecting the wavelength of excitation *** the specificity for lysosomes,2 and 4 have been used in long-term time-lapses imaging of lysosomal dynamics and tracking the process of lysosome-lysosome interaction,fusion and *** effect of hydrogen-containing amino substituent on the cell membrane permeability of fluorescent molecules is promising for the development of better biocompatible probes.

关键词： Amino hydrogen 1,8-Naphthalimide Cell permeability Lipid droplet Lysosome

Improvement of Microstructure and Mechanical Properties of Rapid Cooling Friction Stir-welded A1050 Pure Aluminum

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 134-141页

作者：许楠 LIU Lutao SONG Qining ZHAO Jianhua bao Yefeng College of Materials Science and Engineering Hohai UniversityChangzhou 213200China

Two-mm thick A1050 pure aluminum plates were successfully joined by conventional and rapid cooling friction stir welding(FSW), respectively. The microstructure and mechanical properties of the welded joints were investigated by electron backscatter diffraction characterization, Vickers hardness measurements, and tensile testing. The results showed that liquid CO_(2) coolant significantly reduced the peak temperature and increased the cooling rate, so the rapidly cooled FSW joint exhibited fine grains with a large number of dislocations. The grain refinement mechanism of the FSW A1050 pure aluminum joint was primarily attributed to the combined effects of continuous dynamic recrystallization, grain subdivision, and geometric dynamic recrystallization. Compared with conventional FSW, the yield strength, ultimate tensile strength, and fracture elongation of rapidly cooled FSW joint were significantly enhanced, and the welding efficiency was increased from 80% to 93%. The enhanced mechanical properties and improved synergy of strength and ductility were obtained due to the increased dislocation density and remarkable grain refinement. The wear of the tool can produce several WC particles retained in the joint, and the contribution of second phase strengthening to the enhanced strength should not be ignored.

关键词： aluminum alloy friction stir welding recrystallization microstructure mechanical properties

Emerging WS_(2)/WSe_(2)@graphene nanocomposites: synthesis and electrochemical energy storage applications

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Rare Metals 2024年第1期43卷 1-19页

作者： Yu-Meng Gao Yong Liu Kai-Jia Feng Jun-qing Ma Ying-Jie Miao Bin-Rui xu Kun-Ming Pan Osaka Akiyoshi Guang-Xin Wang Ke-Ke Zhang Qiao-bao Zhang National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials Henan Key Laboratory of Non-Ferrous Materials Science and Processing TechnologySchool of Materials Science and EngineeringHenan University of Science and TechnologyLuoyang 471023China Provincial and Ministerial Co-Construction of Collaborative School of Electrical Engineering Henan University of Science and TechnologyLuoyang 471023China Biomaterials Laboratory Faculty of EngineeringOkayama UniversityTsushima-NakeOkayama-Shi 700-8530Japan Department of Materials Science and Engineering College of MaterialsXiamen UniversityXiamen 361005China Fujian Key Laboratory of Surface and Interface Engineering for High Performance Materials Xiamen UniversityXiamen 361005China

In recent years, tungsten disulfide(WS_(2)) and tungsten selenide(WSe_(2)) have emerged as favorable electrode materials because of their high theoretical capacity, large interlayer spacing, and high chemical activity;nevertheless, they have relatively low electronic conductivity and undergo large volume expansion during cycling, which greatly hinder them in practical applications. These drawbacks are addressed by combining a superior type of carbon material, graphene, with WS_(2) and WSe_(2) to form a WS_(2)/WSe_(2)@graphene *** materials have received considerable attention in electro-chemical energy storage applications such as lithium-ion batteries(LIBs), sodium-ion batteries(SIBs),and supercapacitors. Considering the rapidly growing research enthusiasm on this topic over the past several years, here the recent progress of WS_(2)/WSe_(2)@graphene nanocomposites in electrochemical energy storage applications is summarized. Furthermore, various methods for the synthesis of WS_(2)/WSe_(2)@graphene nanocomposites are reported and the relationships among these methods, nano/microstructures, and electrochemical performance are systematically summarized and discussed. In addition, the challenges and prospects for the future study and application of WS_(2)/WSe_(2)@graphene nanocomposites in electrochemical energy storage applications are proposed.

关键词： WS_(2)/WSe_(2)@graphene nanocomposites Liion batteries(LIBs) Na-ion batteries(SIBs) Supercapacitors Electrochemical performance

Elimination of cracks in stainless steel casings via 3D printed sand molds with an internal topology structure

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China Foundry 2024年第4期21卷 319-326页

作者： Jun-hang xu bao-zhi Li Zhao-wei Song Yun-bao Gao Jing-ming Li Yu Wang Qiu-lin Wen Heng Cao Zeng-rui Wang National Key Laboratory of Advanced Casting Technologies Shenyang 110022China Shenyang Research Institute of Foundry Co. Ltd.CAMShenyang 110022China

The important supporting component in a gas turbine is the casing,which has the characteristics of large size,complex structure,and thin *** the context of existing 3DP sand casting processes,casting crack defects are prone to *** leads to an increase in the scrap rate of casings,causing significant resource ***,the presence of cracks poses a significant safety hazard after the casings are put into *** generation of different types of crack defects in stainless steel casings is closely related to casting stress and the high-temperature concession of the sand ***,the types and causes of cracks in stainless steel casing products,based on their structural characteristics,were systematically *** sand molds with different internal topology designs were printed using the 3DP technology to investigate the impact of sand mold structures on high-temperature *** optimal sand mold structure was used to cast casings,and the crack suppression effect was verified by analyzing its eddy current testing *** experimental results indicate that the skeleton structure has an excellent effect on suppressing cracks in the *** research holds important theoretical and engineering significance in improving the quality of casing castings and reducing production costs.

关键词： gas turbine casing crack defects 3D printed sand mold topological structure high-temperature concession

Photothermal properties of Cu@polycarbonate composites with strong localized surface plasmon resonances

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Nano Research 2024年第9期17卷 8513-8520页

作者： Fengyi Wang Jiangling He Junshan Hu Zhihui Chen Yumeng Shi qing-Hua xu SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of EducationInstitute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China Department of Chemistry National University of Singapore3 Science Drive 3Singapore 117543Singapore College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Copper is relatively low cost and highly abundant compared with the well-studied noble metals such as gold and ***,the poor plasmonic and high susceptibility towards oxidation limit the study of its optical properties and applications as ***,copper nanoparticles@polycarbonate(Cu@PC)composites were prepared by using a facile one-step solvothermal *** Cu@PC composites have strong localized surface plasmon resonances(LSPR)due to that the PC shell can induce the particles to form many-particles system with different particle numbers,which not only lead to overlap and hybridize of the LSPR modes,but also shift the LSPR away from the interband transitions,and the PC layer also prevents the oxidation of Cu *** photothermal conversion efficiency of Cu@PC composites reaches 41.1%under 808 nm continuous wave(CW)laser irradiation which is higher than previously reported Cu nanomaterials that have been ***,the composites also have high photothermal ***,interfacial evaporator is prepared by assembling the Cu@PC composites on scouring sponge as light absorption layer which has>92.8%absorption in entire solar spectrum *** seawater evaporation rate is 3.177 kg·m^(-2)·h^(-1)with a E_(evaporator)/E_(water)of *** high evaporation rate interfacial evaporator with low cost,simple,and scalable approach shows great application value in the field of photothermal evaporation.

关键词： Cu nanoparticles localized surface plasmon resonances(LSPR) photothermal interfacial evaporation