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Rational design and energy catalytic application of high-loading single-atom catalysts

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Rare Metals 2024年第10期43卷 4844-4866页

作者： Zi-Wei Deng Yue Liu Jie Lin Wen-xing Chen Energy and Catalysis Center School of Materials Science and EngineeringBeijing Institute of Technology Ningbo Institute of Materials Technology and Engineering Chinese Academy of Science

It is well known that single-atom catalysts(SACs)have become a hot topic in the field of catalysis due to their advantages such as 100% metal atom utilization efficiency,high catalytic activity and selectivity compared with conventional catalysts and nanocatalysts. However, the isolated metal atoms on SACs have thermodynamic instability and tend to agglomerate, which limit their catalytic ***, it is of great significance to synthesize stable and high-loading single-atom catalysts(HLSACs). In this paper,we review the research progress of HLSACs from two aspects:design and application. Firstly, we comprehensively introduce the synthesis strategies of HLSACs, namely, top-down and bottom-up methods. Secondly, we overview the application status of HLSACs in three fields: electrocatalysis, thermal catalysis and photocatalysis. Finally, we summarize the development prospects and challenges of HLSACs.

关键词： Design Electrocatalysis High-loading single-atom catalysts Photocatalysis Thermal catalysis

Effect of low-speed waterjet pressure on the rock-breaking performance of unsubmerged cavitating abrasive waterjet

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Petroleum Science 2024年第4期21卷 2638-2649页

作者： Chen-xing Fan Deng Li Yong Kang Hai-Tao Zhang Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University School of Power and Mechanical Engineering Wuhan University

Unsubmerged cavitating abrasive waterjet(UCAWJ) has been shown to artificially create a submerged environment that produces shear cavitation, which effectively enhances rock-breaking performance. The shear cavitation generation and collapse intensity depend on the pressure difference between the intermediate high-speed abrasive waterjet and the coaxial low-speed waterjet. However, the effect of the pressure of the coaxial low-speed waterjet is pending. For this purpose, the effect of low-speed waterjet pressure on rock-breaking performance at different standoff distances was experimentally investigated,and the effects of erosion time and ruby nozzle diameter on erosion performance were discussed. Finally,the micromorphology of the sandstone was observed at different locations. The results show that increased erosion time and ruby nozzle diameter can significantly improve the rock-breaking performance. At different standoff distances, the mass loss increases first and then decreases with the increase of low-speed waterjet pressure, the maximum mass loss is 10.4 g at a low-speed waterjet pressure of0.09 MPa. The surface morphology of cavitation erosion was measured using a 3D profiler, the increase in both erosion depth and surface roughness indicated a significant increase in the intensity of the shear cavitation collapse. At a low-speed waterjet pressure of 0.18 MPa, the cavitation erosion surface depth can reach 600 μm with a roughness of 127 μm.

关键词： Rock-breaking Coaxial low-speed waterjet pressure Abrasive waterjet Cavitation Unsubmerged environment

Determining beam transverse absolute position by triangulation of multi-electrode signal phase differences

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Nuclear Science and Techniques 2024年第8期35卷 38-47页

作者： xing Yang Hong‑Shuang Wang Yi‑Mei Zhou Yong‑Bin Leng Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201204China University of Science and Technology of China Hefei 230026China

Accurate measurement of the transverse position of a beam is crucial in particle accelerators because it plays a key role in determining the beam *** methods for beam-position measurement rely on the detection of image currents induced on electrodes or narrow-band wake field induced by a beam passing through a cavity-type ***,these methods have *** indirect measurement of multiple parameters is computationally complex,requiring external calibration to determine the system parameters in ***,the utilization of the beam signal information is ***,this study proposes a novel method for measuring the absolute electron beam transverse *** utilizing the geometric relationship between the center position of the measured electron beam and multiple detection electrodes and by analyzing the differences in the arrival times of the beam signals detected by these electrodes,the absolute transverse position of the electron beam crossing the electrode plane can be *** method features absolute position measurement,a position sensitivity coefficient independent of vacuum chamber apertures,and no requirement for a symmetrical detector electrode *** feasibility of this method is validated through numerical simulations and beam experiments.

关键词： Electron beam bunch-by bunch diagnostics Bunch position measurement Triangulation method Bunch phase Bunch-by-bunch Transverse position Pickup signal

Tuning heterogeneous microstructures to enhance mechanical properties of nano-TiN particle reinforced Haynes 230 composites by laser powder bed fusion

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Rare Metals 2024年第9期43卷 4548-4565页

作者： Wen-Jie Liu Hui Li Qian-xing Yin He-Jun Du School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China The Institute of Technological Sciences Wuhan UniversityWuhan 430072China School of Mechanical&Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

Laser powder bed fusion(LPBF)is considered to be one of the most promising additive manufacturing technologies for producing components with geometries and high geometrical precision that are unattainable by traditional *** superalloy exhibits exceptional mechanical and high-temperature performances,rendering it a prime candidate for advanced aero-engine *** the high demand for LPBF-manufactured superalloys,the superalloy is one of the materials manufactured difficultly by LPBF due to their large laser absorptivity fluctuation,poor molten pool stability and sharp temperature ***,superalloys are characterized by severe pores,undesirable coarse columnar grains and poor mechanical *** this work,the effect of nano-TiN particles on defects,molten pool characteristics and microstructure and performance of the composites were *** 4.5 wt%TiN/Haynes230 samples exhibited exceptional nanohardness and elastic modulus with maximum values reaching 5.53 GPa and 240.03 GPa,*** superior mechanical properties were attributed to the combined effects of spatter and gas pore inhibition,grain refinement and duplex nanophases ***,the stability of molten pool was enhanced,and spatter was effectively suppressed by adding nano-TiN particles,while grain refinement and columnar to equiaxed transitions were ***,the matrix exhibited a high dislocation density due to a significant hindrance of dislocation movement caused by massive nano-phases(e.g.,TiN and M_(23)C_(6)),resulting in the formation of extensive dislocation tangles and *** work offers novel insights into the role of nanoparticles reinforced superalloy composites by LPBF.

关键词： Composites Laser powder bed fusion Molten pool characteristics Microstructure Mechanical properties

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国内绝对重力实验观测比对

大地测量与地球动力学 2008年第4期28卷 72-74页

作者：玄松柏邢乐林何志堂张世伟李辉中国地震局地震研究所陕西省测绘局第一大地测量队西安710054

为标定FG5绝对重力仪及检测其性能,于2008年1月在中国地震局地震研究所的3053测点进行了绝对重力测量比对。研究表明,绝对重力仪FG5-214与FG5-232具有较好的一致性,二者几乎不存在系统误差;两台仪器都具有较强的抗干扰能力,重复性很好,... 详细信息

为标定FG5绝对重力仪及检测其性能,于2008年1月在中国地震局地震研究所的3053测点进行了绝对重力测量比对。研究表明,绝对重力仪FG5-214与FG5-232具有较好的一致性,二者几乎不存在系统误差;两台仪器都具有较强的抗干扰能力,重复性很好,内符合测量精度达(2～3)×10-8ms-2。

关键词：比测绝对重力测量重力变化地震测量精度

Cage-confinement synthesis of MoC nanoclusers as efficient sulfiphilic and lithiophilic regulator for superior Li–S batteries

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Rare Metals 2024年第2期43卷 624-634页

作者： xing-Yuan Zhang Mei-Na Lei Shan Tian Jian-Gan Wang State Key Laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene(NPU)Xi’an710072China

High-energy-density Li-S batteries are subjected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite *** this work,a controllable cage-confinement strategy to fabricate molybdenum carbide(MoC)nanoclusters as a high-efficient sulfiphilic and lithiophilic regulator to mitigate the formidable issues of Li-S batteries is *** sub-2 nm MoC nanoclusters not only guarantee robust chemisorption and fast electrocatalytic conversion of polysulfides to enhance the sulfur electrochemistry,but also homogenize Li^(+) flux to suppress the lithium dendrite *** a consequence,the MoC-modified separator endows the batteries with boosted reaction kinetics,promoted sulfur utilization,and improved cycling stability.A reversible capacity of 701 mAh·g^(−1) at a high rate of 5.0C and a small decay rate of 0.076%per cycle at 1.0C over 600 cycles are *** study offers a rational route for design and synthesis of bifunctional nanoclusers with both sulfiphilicity and lithiophilicity for high-performance Li-S batteries.

关键词： Li-S batteries Nanocluster Electrocatalyst Polysulfide shuttle Li dendrites

STABILITY OF TRANSONIC SHOCKS TO THE EULER-POISSON SYSTEM WITH VARYING BACKGROUND CHARGES

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Acta Mathematica Scientia 2024年第4期44卷 1487-1506页

作者： Yang CAO Yuanyuan xing Na ZHANG School of Mathematical Sciences Dalian University of TechnologyDalian 116024China

This paper is devoted to studying the stability of transonic shock solutions to the Euler-Poisson system in a one-dimensional nozzle of finite *** background charge in the Poisson equation is a piecewise constant *** structural stability of the steady transonic shock solution is obtained by the monotonicity ***,this transonic shock is proved to be dynamically and exponentially stable with respect to small perturbations of the initial *** of the crucial ingredients of the analysis is to establish the global well-posedness of a free boundary problem for a quasilinear second order equation with nonlinear boundary conditions.

关键词： Euler-Poisson system transonic shock varying background charges stability

Surface diffraction beamline at the SSRF

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Nuclear Science and Techniques 2024年第7期35卷 47-57页

作者： Yue-Liang Gu Xu Zheng xing-Min Zhang Bin Zhao Guang-Zhi Yin Da-Ming Zhu Yuan-He Sun xing-Yu Gao Xiao-Long Li Shanghai Advanced Research Institute Chinese Academy of Sciences239 Zhangheng RoadPudong DistrictShanghai201204China

BL02U2 of the Shanghai Synchrotron Radiation Facility is a surface diffraction beamline with a photon flux of 5.5×10^(12) photons/s at 10 keV and a beam size of 160µm×80µm at the sample *** is dedicated to studying surfaces(solid-vacuum,solid-gas)and interfaces(solid-solid,solid-liquid,and liquid-liquid)in nanoscience,condensed matter,and soft matter systems using various surface scattering techniques over an energy range of 4.8-28 keV with transmission and reflection ***,BL02U2 has a high energy resolution,high angular resolution,and low beam divergence,which can provide excellent properties for X-ray diffraction experiments,such as grazing incident X-ray diffraction,X-ray reflectivity,crystal truncation rods,and liquid X-ray *** of in situ environments can also be provided for the samples *** paper describes the setup of the new beamline and its applications in various fields.

关键词： Surface and interface Beamline Surface diffraction Microstructure

Investigation of gravity influence on EOR and CO_(2) geological storage based on pore-scale simulation

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Petroleum Science 2024年第2期21卷 987-1001页

作者： Yong-Mao Hao Gui-Cheng Wu Zong-Fa Li Zhong-Hui Wu Yong-Quan Sun Ran Liu xing-xing Li Bo-Xin Pang Nan Li Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao266580ShandongChina School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina School of Petroleum Engineering Yangtze UniversityWuhan430100HubeiChina Dongsheng Jinggong Petroleum Development Group Co. LtdShengli Oilfield CompanySINOPECDongying257001ShandongChina

Gravity assistance is a critical factor influencing CO_(2)-Oil mixing and miscible flow during EOR and CO_(2)geological *** on the Navier-Stokes equation,component mass conservation equation,and fluid property-composition relationship,a mathematical model for pore-scale CO_(2) injection in oilsaturated porous media was developed in this *** model can reflect the effects of gravity assistance,component diffusion,fluid density variation,and velocity change on EOR and CO_(2) *** nonhomogeneous porous media,the gravity influence and large density difference help to minimize the velocity difference between the main flow path and the surrounding area,thus improving the oil recovery and CO_(2) *** CO_(2) injection angles and oil-CO_(2) density differences can increase the oil recovery by 22.6% and 4.2%,respectively,and increase CO_(2) storage by 37.9% and 4.7%,*** diffusion facilitates the transportation of the oil components from the low-velocity region to the main flow path,thereby reducing the oil/CO_(2) concentration difference within the porous *** diffusion can increase oil recovery and CO_(2) storage by 5.7% and 6.9%,*** addition,combined with the component diffusion,a low CO_(2) injection rate creates a more uniform spatial distribution of the oil/CO_(2) component,resulting in increases of 9.5% oil recovery and 15.7% CO_(2) storage,*** study provides theoretical support for improving the geological CO_(2) storage and EOR processes.

关键词： Gravity Flow simulation CO_(2)-oil mixing Enhanced oil recovery(EOR) Geological storage