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Numerical investigation on dynamic response of the screen mesh in vibrating screening through DEM-FEM co-simulation

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Particuology 2024年第4期87卷 205-217页

作者： Huan zhang xiao Zheng Weimin Jing Key Laboratory of MetallurgicalEquipment and Control Technology Ministry of EducationWuhan University of Science and TechnologyWuhan430081 China Hubei Key Laboratory of Mechanical Transmssion and Manufacturing Engineering Wuhan University of Science and TechnologyWuhan430081China College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing400044China

Dynamic response of the screen mesh is of great significance in the optimum vibrating screen *** this paper,based on the DEM-FEM co-simulation method,the effect of screening parameters on the dynamic response of the screen mesh is explored and the mechanism is revealed on the particle ***,a virtual experiment on a linear vibrating screen was carried out to analyze the screening pa-rameters'effect with both impact load and sustained stress inflicted on the screen ***,the time-domain evolution regularity of the screen mesh LVA(Local Vibration Amplitude)under different particle plugging conditions was investigated based on the ***,the influence of screening parameters on LVA and its distribution was *** results show that the screening parameters can greatly affect the screen mesh LVA and its distribution by changing the movement of the granular material and the particle penetration probability,which provides an important basis for the optimal design of the screen mesh and its supporting structure.

关键词： Vibrating screen Dynamic response DEM-FEM Screening parameters Local vibration amplitude

Nuclear volume effects in kinetic isotope fractionation:A case study of mercury oxidation by chlorine species

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Acta Geochimica 2024年第3期43卷 411-423页

作者： Chenlu Yang Yining zhang yun Liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

It is well-known that the equilibrium isotope fractionation of mercury(Hg)includes classical massdependent fractionations(MDFs)and nuclear volume effect(NVE)induced mass-independent fractionations(MIFs).However,the effect of the NVE on these kinetic processes is not *** total fractionations(MDFs+NVEinduced MIFs)of several representative Hg-incorporated substances were selected and calculated with ab initio calculations in this work for both equilibrium and kinetic ***-induced MIFs were calculated with scaled contact electron densities at the nucleus through systematic evaluations of their accuracy and errors using the Gaussian09 and DIRAC19 packages(named the electron density scaling method).Additionally,the NVE-induced kinetic isotope effect(KIE)of Hg isotopes are also calculated with this method for several representative Hg oxidation reactions by chlorine *** KIEs for 202 Hg/^(198)Hg ranging from−2.27‰to 0.96‰are *** anomalous^(202)Hg-enriched KIEs(δ^(202)Hg/^(198)Hg=0.83‰,0.94‰,and 0.96‰,)caused by the NVE are observed,which are quite different from the classical view(i.e.,light isotopes react faster than the heavy ones).The electron density scaling method we developed in this study can provide an easier way to calculate the NVE-induced KIEs for heavy isotopes and serve to better understand the fractionation mechanisms of mercury isotope systems.

关键词： Nuclear volume effect Kinetic fractionation Hg isotopes Ab initio calculations

Accurate Distinction of Weak and Strong AC Grids for Emerging Hierarchical-Infeed LCC-UHVDC Systems

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 772-777页

作者： Hao xiao Xianzhong Duan Yi zhang Department of Electrical and Computer Engineering University of ManitobaWinnipeg R3T 2N2ManitobaCanada State Key Laboratory of Advanced Electromagnetic Engineering and Technology Hubei Electric Power Security and High Efficiency Key LaboratorySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina RTDS Technologies Inc. Winnipeg R3T 2E1ManitobaCanada

Distinction of weak and strong AC grids for emerging hierarchical-infeed LCC-UHVDC systems is important for planning and operation departments. However, accuracy of earlier distinction methods is limited as they were developed by empirical reasoning without rigorous theoretical analysis. Hence in this letter, hierarchical-infeed interactive effective short-circuit ratio (HIESCR) index is first used for strength evaluation of HIDC systems with complex inter-inverter interactions considered. Boundary HIESCR (BHIESCR) is also introduced in the proposed distinction method of weak and strong AC grids. That is, weak (or strong) AC grids are, respectively, identified when HIESCR is less (or greater) than BHIESCR. Second, it is shown BHIESCR remains almost unchanged as 3.0 versus various system parameters and rated operation variables based on rigorous theoretical analysis. This salient feature makes the proposed method more accurate than earlier methods. Finally, the proposed method is validated by simulations based on the PSCAD/EMTDC program.

关键词： Hierarchical-Infeedinteractive effective short-circuit ratio hierarchical-infeed LCC-UHVDC systems inter-inverter interactions strong AC grids weak AC grids

Preparation of tungsten-particle-reinforced Zr-based bulk metallic glass composites by two-step spark plasma sintering:microstructure evolution,densification mechanism and mechanical properties

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Rare Metals 2024年第4期43卷 1793-1808页

作者： yun-Fei Ma Pan Gong Mao zhang Hui-EHu Zhen Peng xiao Xu Xin Wang Mehdi Malekan Xue-Feng Tang Lei Deng Jun-Song Jin Xin-yun Wang State Key Laboratory of Materials Processing and Die and Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Research Institute of Huazhong University of Science and Technology in Shenzhen Shenzhen518057China Department of Chemistry and Materials Naval University of EngineeringWuhan430032China School of Materials Science and Engineering Jiangsu UniversityZhenjiang212013China College of Machine Shanghai Dianji UniversityShanghai201306China School of Metallurgy and Materials Engineering College of EngineeringUniversity of TehranTehran 11155-4563Iran

A new two-step spark plasma sintering(TSS)process with low-temperature pre-sintering and high-temperature final sintering has been successfully applied to prepare the tungsten-particle(Wp)-reinforced bulk metallic glass composites(Wp/BMGCs).Compared to normal spark plasma sintering(NS),the densification rate and relative density of Wp/BMGCs can be improved by selecting TSS with appropriate sintering pressure in the low temperature pre-sintering ***,the compressive strength and plastic strain of 30%Wp/BMGCs prepared by TSS are both higher than those of the samples prepared by *** TSS process can significantly enhance the compressive strength of 30%Wp/BMGCs by 12%and remarkably increase the plastic strain by 50%,while the trend is completely opposite for 50%Wp/***-in situ experiments and finite element simulations reveal that uneven temperature distribution among particles during low-temperature pre-sintering causes local overheating at contact points between particles,accelerating formation of sintering neck between particles and plastic deformation of *** the volume fraction of Wp is low,TSS can improve the interface bonding between particles by increasing the number of sintering *** makes the fracture mode of Wp/BMGCs being predominantly transgranular ***,as the volume fraction of Wp increases,the adverse effects of Wp plastic deformation are becoming more and more *** aggregated Wp tends to form a solid"cage structure"that hinders the bonding between particles at the interface;correspondingly,the fracture behavior of Wp/BMGCs is mainly dominated by intergranular ***,reducing the sintering pressure during the low-temperature pre-sintering stage of TSS has been shown to effectively decrease plastic deformation in Wp,resulting in a higher degree of densification and better mechanical properties.

关键词： Bulk metallic glass composites Tungsten particle Two-step spark plasma sintering Densification mechanism Mechanical properties

Sedimentary lithofacies characteristics and sweet-spot interval characterization of the Sinian Doushantuo Formation in Upper Yangtze Platform, South China

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China Geology 2019年第3期2卷 261-275页

作者： Yu-fang Wang Gang-yi Zhai Yong-chao Lu Yi-quan Ma Juan Li Guo-heng Liu yun-xiao zhang Oil and Gas Survey China Geological SurveyMinistry of Natural ResourcesBeijing 100083China Unconventional Oil and Gas Geology Laboratory China Geological SurveyMinistry of Natural ResourcesBeijing 100083China China University of Geosciences Wuhan 430074China

The Sinian Doushantuo Formation is the oldest shale gas reservoir discovered in the world, which contains good shale gas shows as the Eyangye-1 and Zidi-1 wells in the Yichang Region of western Hubei province, China. The shales in the Doushantuo Formation feature considerable thickness (135 m), high gas content (4.83 m^3/t) and high fragile mineral content (up to 75%). Due to the influences of the sedimentary environment, the shale reservoirs here have high dolomitic content (54%) and abruptly changes in vertical lithofacies. Moreover, the characteristics of the shale sweet-spot differ significantly from that in the Wufeng Formation and Longmaxi Formation in southeast Sichuan Basin. A high-resolution sequence stratigraphic correlation was performed on the shales of the Doushantuo Formation at the Eyangye-1 well, Zidi-1 well, Zidi-2 well and some outcrop profiles in Yichang area for the identification of their sedimentary microfacies characteristics. A comprehensive comparative analysis was made by incorporating the elemental geochemistry, wireline and mud logging data of the well to further identify the sweet-spot interval therein. With the analysis of Eyangye-1 well, the sweet-spot interval of the Doushantuo Formation is 3360?3408 m, of which sedimentary microfacies is deepwater reduced environment with many pyrite laminaes, and the TOC is high to 3.42%, the Ro is 3.3%, the organic and matrix pore are well developed and the aperture more than 50 nm, the porosity is 2.7%, the desorption gas content average is 2.16%, and the main mineral is dolomitic (54%) and siliceous quartz (21%). Additionally, these parameters combined with previous studies will shed light on evaluating and characterizing the layers therein, also provide referential geological data for the following exploration and development activities of this shale system.

关键词： Shale gas Sequence correlation Sweet-spot interval Doushantuo Formation (Late Proterozoic) Upper Yangtze Platform Oil and gas exploration engineering Hubei Province China

Adversarial attacks and defenses for digital communication signals identification

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Digital Communications and Networks 2024年第3期10卷 756-764页

作者： Qiao Tian Sicheng zhang Shiwen Mao yun Lin College of Computer Science and Technology Harbin Engineering UniversityHarbin150001China College of Information and Communication Engineering Harbin Engineering UniversityHarbin150000China Department of Electrical and Computer Engineering Auburn UniversityAuburnAL36849USA

As modern communication technology advances apace,the digital communication signals identification plays an important role in cognitive radio networks,the communication monitoring and management *** has become a promising solution to this problem due to its powerful modeling capability,which has become a consensus in academia and ***,because of the data-dependence and inexplicability of AI models and the openness of electromagnetic space,the physical layer digital communication signals identification model is threatened by adversarial *** examples pose a common threat to AI models,where well-designed and slight perturbations added to input data can cause wrong ***,the security of AI models for the digital communication signals identification is the premise of its efficient and credible *** this paper,we first launch adversarial attacks on the end-to-end AI model for automatic modulation classifi-cation,and then we explain and present three defense mechanisms based on the adversarial *** we present more detailed adversarial indicators to evaluate attack and defense ***,a demonstration verification system is developed to show that the adversarial attack is a real threat to the digital communication signals identification model,which should be paid more attention in future research.

关键词： Digital communication signals identification AI model Adversarial attacks Adversarial defenses Adversarial indicators

Mechanical Performance of Bio-inspired Bidirectional Corrugated Sandwich Pressure Shell Under External Hydrostatic Pressure

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China Ocean Engineering 2024年第2期38卷 297-312页

作者： zhang Yi CHEN Yue yun Lai LIANG Xu Ocean College Zhejiang UniversityZhoushan 316000China Hainan Institute Zhejiang UniversitySanya 572000China

This paper aims to enhance the compression capacity of underwater cylindrical shells by adopting the corrugated sandwich structure of *** cuttlebone suffers uniaxial external compression,while underwater cylindrical shells are in a biaxial compressive stress *** suit the biaxial compressive stress state,a novel bidirectional corrugated sandwich structure is proposed to improve the bearing capacity of cylindrical *** static and buckling analysis for the sandwich shell and the unstiffened cylindrical shell with the same volume-weight ratio are studied by numerical *** is indicated that the proposed sandwich shell can effectively reduce the ratio between circumferential and axial stress from 2 to 1.25 and improve the critical buckling load by about 1.63 *** simulation shows that optimizing and adjusting the structural parameters could significantly improve the advantage of the sandwich ***,the hydrostatic pressure tests for shell models fabricated by 3D printing are carried *** to the experimental results,the overall failure position of the sandwich shell is at the center part of the sandwich *** has been found the average critical load of the proposed sandwich shell models exceeds two times that of the unstiffened shell ***,the proposed bio-inspired bidirectional corrugated sandwich structure can significantly enhance the pressure resistance capability of cylindrical shells.

关键词： bio-inspiration bidirectional corrugation sandwich shell external pressure buckling

Plasma spray coating on interconnector toward promoted solid oxide fuel cells and solid oxide electrolysis cells

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Frontiers in Energy 2024年第3期18卷 390-398页

作者： Junwen CAO yun ZHENG Wenqiang zhang Bo YU Institute of Nuclear and New Energy Technology(INET) Collaborative Innovation Center of Advanced Nuclear Energy TechnologyTsinghua UniversityBeijing 100084China Department of Chemical Engineering University of WaterlooWaterlooOntario N2L 3G1Canada Institute of New Energy Materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China

Interconnector is a critical component to construct solid oxide cells (SOCs) stack. Oxidation of metallic interconnectors and Cr poisoning caused by oxidation are important factors that lead to long-term performance degradation of SOCs. Coating on the interconnector surface is an important approach to inhibit the oxidation and Cr migration of the interconnector. Herein, (La0.75Sr0.25)0.95MnO3–δ (LSM) and Mn1.5Co1.5O4 (MCO) are used to fabricate the coatings of interconnector. Two advanced thermal spray technology, atmospheric plasma spraying (APS) and low-pressure plasma spray (LPPS), are adopted for the coating preparation. The electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition performance of the coatings are tested and evaluated. The result indicates that MCO can generate more uniform and denser coatings than LSM. In addition, MCO coatings prepared by LPPS shows the best electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition. The initial area specific resistance (ASR) is 0.0027 Ω·cm2 at 800 °C. After 4 cooling cycle tests, the ASR increases to 0.0032 Ω·cm2 but lower than other samples. Meanwhile, the relative intense of Cr at the interface of SUS430 with MCO coatings fabricated by LPPS is lower than that of MCO fabricated by APS after 4 rising and cooling cycle operations, showing more favorable Cr diffusion inhibition performance.

关键词： interconnector coating plasma spray electrochemical performance Cr diffusion inhibition solid oxide cells(SOCs)

Characterizations of semihoops based on derivations

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 291-310页

作者： WANG Mei zhang xiao-hong School of Electrical and Control Engineering Shaanxi University of Science and TechnologyXi'an 710021China School of Arts and Sciences Shaanxi University of Science and TechnologyXi'an 710021China School of Mathematics and Statistics Weinan Normal UniversityWeinan 714099China

In this paper,we discuss the related properties of some particular derivations in semihoops and give some characterizations of ***,we prove that every Heyting algebra is isomorphic to the algebra of all multiplicative derivations and show that every Boolean algebra is isomorphic to the algebra of all implicative ***,we show that the sets of multiplicative and implicative derivations on bounded regular idempotent semihoops are in oneto-one correspondence.

关键词： (prelinear)semihoop derivation Heyting algebra Galois connection