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Influence of pressure disturbance wave on dynamic response characteristics of liquid film seal for multiphase pump

Petroleum Science 2024年第3期21卷 2048-2065页

作者： Qing-Ping li Jin-Ya Zhang Jia-Xiang Zhang Yong-xue Zhang CNOOC Research Institute Company limited Beijing100028China State Key Laboratory of Natural Gas Hydrate Beijing100028China College of Mechanical and Transportation Engineering China University of PetroleumBeijing2249China

Slug flow or high GVF(Gas Volume Fraction)conditions can cause pressure disturbance waves and alternating loads at the boundary of mechanical seals for multiphase pumps,endangering the safety of multiphase pump *** mechanical seal model is simplified by using periodic boundary conditions and numerical calculations are carried out based on the Zwart-Gerber-Belamri cavitation ***(User Define Function)programs such as structural dynamics equations,alternating load equations,and pressure disturbance equations are embedded in numerical calculations,and the dynamic response characteristics of mechanical seal are studied using layered dynamic mesh *** results show that when the pressure disturbance occurs at the inlet,as the amplitude and period of the disturbance increase,the film thickness gradually *** the fundamental reason for the hysteresis of the film thickness change is that the pressure in the high-pressure area cannot be restored in a timely *** maximum value of leakage and the minimum value of axial velocity are independent of the disturbance period and determined by the disturbance *** mutual interference between enhanced waves does not have a significant impact on the film thickness,while the front wave in the attenuated wave has a promoting effect on the subsequent film thickness changes,and the fluctuation of the liquid film cavitation rate and axial velocity under the attenuated wave condition deviates from the initial *** with pressure disturbance conditions,alternating load conditions have a more significant impact on film thickness and *** actual operation,it is necessary to avoid alternating load conditions in multiphase pump mechanical seals.

关键词： Multiphase pump liquid film seal Pressure disturbance wave Dynamic response characteristics

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Rational design of vitamin C/defective carbon van der Waals heterostructure for enhanced activity,durability and storage stability toward oxygen reduction reaction

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Journal of Energy Chemistry 2024年第1期88卷 103-111,I0003页

作者： Ruiqi Cheng Kaiqi li Huanxin li Tianshuo Zhao Yibo Wang Qingyue xue Jiao Zhang Chaopeng Fu Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Christopher Ingold Laboratory Department of ChemistryUniversity College LondonLondon WC1H 0AJUK Department of Chemistry Physical&Theoretical Chemistry LaboratoryUniversity of OxfordSouth Parks RoadOxford OX13QZUK

Metal-free defective carbon materials with abundant active sites have been widely studied as low-cost and efficient oxygen reduction reaction(ORR)electrocatalysts in metal-air ***,the active sites in defective carbon are easily subjected to serious oxidation or hydroxylation during ORR or storage,leading to rapid degradation of ***,we design a van der Waals heterostructure comprised of vitamin C(VC)and defective carbon(DC)to not only boost the activity but also enhance the durability and storage stability of the DC-VC *** formation of VC van der Waals between DC and VC is demonstrated to be an effective strategy to protect the defect active sites from oxidation and hydroxylation degradation,thus significantly enhancing the electrochemical durability and storage anti-aging ***,the DC-VC van der Waals can reduce the reaction energy barrier to facilitate the *** findings are also confirmed by operando Fourier transform infrared spectroscopy and density functional theory *** is necessary to mention that the preparation of this DC-VC electrocatalyst can be scaled up,and the ORR performance of the largely produced electrocatalyst is demonstrated to be very ***,the DC-VC-based aluminum-air batteries display very competitive power density with good performance maintenance.

关键词： Van der Waals heterostructure Oxygen reduction reaction Stability Scalable production Aluminum-air battery

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Electrochemical Cascade Annulation for the Synthesis of 3-Sulfanylquinoline Derivatives under Mild Conditions

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Chinese Journal of Chemistry 2024年第16期42卷 1833-1838页

作者： Ke li Ming-Zhong Guo Zhuo Chen Hao-Ran li Weisi Guo Ming li lin-bao Zhang State Key Laboratory Base of Eco-Chemical Engineering College of Chemistry and Molecular EngineeringQingdao University of Science&TechnologyQingdaoShandong 266042China

An efficient electrochemical approach has been developed for the construction of 3-sulfanylquinoline derivatives by treating phenylethynylbenzoxazinanones with disulfides in an undivided *** protocol provided a convenient route to functionalized quinolines with good functional group ***,it does not require any metal catalysts or additives,furnishing a series of biologicalquinolines inmoderatetogoodyields.

关键词： Electrocatalysis Electrooxidation Annulation 3-Sulfany quinoline C3-thioetherification

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Experimental investigation on coal pore-fracture variation and fractal characteristics synergistically affected by solvents for improving clean gas extraction

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International Journal of Mining Science and Technology 2024年第3期34卷 413-425页

作者： Feilin Han Sheng xue Chunshan Zheng Zhongwei Chen Guofu li Bingyou Jiang Key Laboratory of Safe and Effective Coal Mining of Ministry of Education Anhui University of Science and TechnologyHuainan 232001China School of Safety Science and Engineering Anhui University of Science and TechnologyHuainan 232001China School of Mechanical and Mining Engineering University of QueenslandQLD 4072Australia State Key Laboratory of Coal and Coalbed Methane Co-Mining Jincheng 048012China

Chemical solvents instead of pure water being as hydraulic fracturing fluid could effectively increase permeability and improve clean methane extraction ***,pore-fracture variation features of lean coal synergistically affected by solvents have not been fully *** testing,nuclear magnetic resonance analysis,liquid phase mass spectrometry was adopted to comprehensively analyze pore-fracture change characteristics of lean coal treated by combined solvent(NMP and CS_(2)).Meanwhile,quantitative characterization of above changing properties was conducted using geometric fractal *** model between permeability,fractal dimension and porosity were *** indicate that the end face fractures of coal are well developed after CS2and combined solvent treatments,of which,end face box-counting fractal dimensions range from 1.1227 to *** decreases in ultrasonic longitudinal wave velocity of coal affected by NMP,CS_(2)and combined solvent are 2.700%,20.521%,22.454%,*** treatments could lead to increasing amount of both mesopores and *** ratio of fractal dimension Dsis 0.259%–2.159%,while permeability increases ratio of NMR ranges from 0.1904 to ***,combined solvent could dissolve coal polar and non-polar small molecules and expand flow *** could provide reference for solvent selection and parameter optimization of permeability-enhancement technology.

关键词： Clean gas extraction Chemical solvent Experimental investigation Fractal characteristics Pore fracture

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Synthesis of uniform two-dimensional MoS_(2) films via thermal evaporation

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Nano Research 2024年第4期17卷 3217-3223页

作者： xue-Wei Lu Zhewei li Chen-Kai Yang Weijia Mou liying Jiao Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education Department of ChemistryTsinghua UniversityBeijing 100084China

Two-dimensional(2D)molybdenum disulfide(MoS_(2))holds great potential for various applications such as electronic devices,catalysis,lubrication,anti-corrosion and so *** evaporation is a versatile thin film deposition technique,however,the conventional thermal evaporation techniques face challenges in producing uniform thin films of MoS_(2) due to its high melting temperature of 1375℃.As a result,only thick and rough MoS_(2) films can be obtained using these *** address this issue,we have designed a vacuum thermal evaporation system specifically for large-scale preparation of MoS_(2) thin *** using K2MoS4 as the precursor,we achieved reliable deposition of uniform polycrystalline MoS_(2) thin films with a size of 50 mm×50 mm and controllable thickness ranging from 0.8 to 2.4 *** approach also allows for patterned deposition of MoS_(2) using shadow masks and sequential deposition of MoS_(2) and tungsten disulfide(WS_(2)),similar to conventional thermal evaporation ***,we have demonstrated the potential applications of the obtained MoS_(2) thin films in field effect transistors(FETs),memristors and electrocatalysts for hydrogen evolution reaction(HER).

关键词： thermal evaporation molybdenum disulfide two-dimensional memristors hydrogen evolution reaction

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Improving strength-ductility synchronously of Electron beam welded Ti600/Ti2AlNb joint through isothermal forging

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Progress in Natural Science:Materials International 2024年第3期34卷 532-539页

作者： Yongqiang Zhang Xiangyi xue Guoming Zheng Jingli Zhang Huiming li Shewei Xin State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an Qin Ti Intelligent Manufacturing Technologies Co.Ltd. Northwest Institute for Nonferrous Metal Research Xi'an University of Science and Technology Avic Xi'an Aircraft Industry Group Company Ltd.

Different alloys can be flexibly combined to meet the performance needs of different parts of the compressor disc by welding process. However, achieving a good combination of dissimilar alloys with different mechanical properties has always been a research difficulty. In this work, a Ti600/Ti2AlNb joint was fabricated through electron beam welding and an isothermal forging was used to optimized its microstructure and mechanical performance. The isothermal forging process increases the ultimate tensile strength（UST） and yield strength（YS）of the Ti600/Ti2AlNb joint by ～18 %, while ～2.5 times the ductility. It is indicated that before forging, the Ti600/Ti2AlNb joint exhibits a much lower strength than that of Ti600 matrix, whereas the opposite is true after isothermal forging. The isothermal forging broken the coarse columnar grains of Ti600/Ti2AlNb joint and render to an equiaxed B2 structure in which the acicular α2and O phase are precipitated, resulting a synchronous enhancement of strength and ductility. This work may pave an effective routine for improving the comprehensive mechanical properties of dissimilar metal welding joint.

关键词： Electron beam welding Isothermal forging Mechanical performance Ti600/Ti2AlNb joint

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Magnetic behaviors and magnetocaloric effects in rare earth high-entropy amorphous/nanocrystalline alloys

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Journal of Rare Earths 2024年第1期42卷 129-136,I0005页

作者： lin xue liliang Shao baosen Zhang Zongzhen li Jiangbo Cheng baolong Shen College of Mechanics and Materials Hohai UniversityNanjing211106China School of Materials Science and Engineering Jiangsu Key Laboratory of Advanced Metallic MaterialsSoutheast UniversityNanjing211189China School of Materials Science and Engineering Nanjing Institute of TechnologyNanjing211167China Jiangsu JITRI Advanced Energy Materials Research Institute Co. Ltd.Changzhou213000China

Rare earth high-entropy alloys(RE-HEAs)exhibit great potential to be applied as refrigerants due to their good comprehensive magnetocaloric *** this work,octary GdTbDyHoErTmCoAl and GdTbDyHoErTmCoNi RE-HEAs with amorphous/nanocrystalline structure exhibiting comparable magnetocaloric effect were *** RE-HEAs show a second-order magnetic phase transition in the temperature range of hydrogen *** to the complex magnetic interactions,a spin glasslike behavior at low temperatures is observed in the RE-HEAs.A superior magnetocaloric effect is obtained in the nanocrystalline GdTbDyHoErTmCoNi high-entropy alloy that is multiphase attributed to a stronger magnetic exchange interaction when compared with the other that exhibits single amorphous *** heterogeneous microstructure,homogeneous chemical distributions are observed in the partially crystallized high-entropy *** addition,the magnetocaloric effect and magnetic transition behavior of rare earth medium-and high-entropy alloys,including the RE-HEAs in this study,are summarized and *** results in this work provide a helpful guide for the design of RE-HEAs for hydrogen liquefaction applications with excellent magnetocaloric effects.

关键词： Rare earths High-entropy alloy Metallic glass Magnetocaloric effect

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Reinforcement learning based edge computing in B5G

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Digital Communications and Networks 2024年第1期10卷 1-6页

作者： Jiachen Yang Yiwen Sun Yutian Lei Zhuo Zhang Yang li Yongjun bao Zhihan Lv School of Electrical and Information Engineering Tianjin UniversityTianjin300072China Technology and Data Center ***Beijing100176China School of Data Science and Software Engineering Qingdao UniversityQingdao266101China

The development of communication technology will promote the application of Internet of Things,and Beyond 5G will become a new technology *** the same time,Beyond 5G will become one of the important supports for the development of edge computing *** paper proposes a communication task allocation algorithm based on deep reinforcement learning for vehicle-to-pedestrian communication scenarios in edge *** trial and error learning of agent,the optimal spectrum and power can be determined for transmission without global information,so as to balance the communication between vehicle-to-pedestrian and *** results show that the agent can effectively improve vehicle-to-infrastructure communication rate as well as meeting the delay constraints on the vehicle-to-pedestrian link.

关键词： Reinforcement learning Edge computing Beyond 5G Vehicle-to-pedestrian

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An adaptive finite-difference method for seismic traveltime modeling based on 3D eikonal equation

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Petroleum Science 2024年第1期21卷 195-205页

作者： bao-Ping Qiao Qing-Qing li Wei-Guang He Dan Zhao Qu-Bo Wu CNNC Beijing Research Institute of Uranium Geology Beijing 100029China National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao 266580ShangdongChina SINOPEC Geophysical Research Institute Nanjing211103JiangsuChina

3D eikonal equation is a partial differential equation for the calculation of first-arrival traveltimes and has been widely applied in many scopes such as ray tracing,source localization,reflection migration,seismic monitoring and tomographic *** recent years,many advanced methods have been developed to solve the 3D eikonal equation in heterogeneous ***,there are still challenges for the stable and accurate calculation of first-arrival traveltimes in 3D strongly inhomogeneous *** this paper,we propose an adaptive finite-difference(AFD)method to numerically solve the 3D eikonal *** novel method makes full use of the advantages of different local operators characterizing different seismic wave types to calculate factors and traveltimes,and then the most accurate factor and traveltime are adaptively selected for the convergent updating based on the Fermat *** with global fast sweeping describing seismic waves propagating along eight directions in 3D media,our novel method can achieve the robust calculation of first-arrival traveltimes with high precision at grid points either near source point or far away from source point even in a velocity model with large and sharp *** numerical examples show the good performance of the AFD method,which will be beneficial to many scientific applications.

关键词： 3D eikonal equation Accurate traveltimes Global fast sweeping 3D inhomogeneous media Adaptive finite-difference method

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Copper-based nanodots as efficient biomimetic antibiotics for the treatment of oral bacterial infections Author links open overlay panel

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Particuology 2024年第8期91卷 190-201页

作者： Ying li Nan Tang lingling Zhao Xingfu bao Yuzhuo Wang Zhanxin Wang Min Hu Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling School and Hospital of StomatologyJilin UniversityChangchunChina Beijing Advanced Innovation Center for Soft Matter Science and Engineering College of Life Science and TechnologyBeijing University of Chemical TechnologyBeijingChina

Oral infectious diseases caused by a variety of pathogenic bacteria seriously affect the quality of ***,these diseases remain a clinical challenge because of the lack of simple,safe,and universal *** address these limitations,we synthesize CuO_(x)nanodots(CuO_(x)NDs)with excellent Fenton-like reaction activity and utilize them in the treatment of oral bacterial *** from other complicated approaches,CuO_(x)NDs are rationally prepared using a facile one-pot aqueous *** the presence of H_(2)O_(2),these well-developed CuO_(x)NDs can efficiently catalyze the generation of hydroxyl radicals(·OH)around oral pathogens,leading to the death of various ***,results of biosafety indicate the high biocompatibility and extremely low toxicity of these CuO_(x)*** understanding the admirable in vitro antibacterial effect of CuO_(x)NDs in the presence of H_(2)O_(2),we further explore their in vivo antibacterial performance on several classical animal models including oral mucosal wound model,intragingival bacteria-infected model,and the periodontal infection *** expected,these CuO_(x)NDs with wide-spectrum antibacterial activity can serve as high-performance antibacterial reagents for the treatment of various oral bacterial infections with the help of H_(2)O_(2).In brief,current nanoplatform can act as efficient antibiotics against oral pathogens with broadening the biomedical applications of copper-based nanomaterials.

关键词： Antibacterial treatment Oral diseases Fenton-likecatalytic reaction Reactive oxygen species

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