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Influence of friction-lubrication characteristics varying with rolling speed on instability of chatter and slip in cold tandem rolling process

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Journal of Iron and Steel Research International 2024年第4期31卷 894-908页

作者： Yan-li Xin Zhi-ying Gao bo Tian qing-dong Zhang School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China

In the high-speed cold tandem rolling process of thin plate,chatter or slip instability gives rise to the deterioration of equipment and product *** instability behavior is closely related to interfacial friction-lubrication con-dition which is generally characterized by the friction ***,with higher and higher speed requirements,the commonly used model of friction coefficient is no longer applicable and accurate.A novel approach is suggested to calculate the speed-dependent friction coefficient,in which the viscosity-pressure-temperature effects of the lubricant,surface roughness states of work rolls and rolled piece are comprehensively involved and the mixed flm lubrication theory is ***,the influences of friction coefficient on the instability of slip and chatter are investigated for a five-stand cold tandem rolling *** one side,the critical friction coefficient for each stand is determined by calculating the corresponding slip factor;on the other hand,the friction coefficient varying with rolling speed is combined with the model of theoretical critical rolling speed presented under constant friction coefficient,so that the speed threshold is ***,the stable and unstable regions corresponding to the rear three stands are individually discussed,and the technical strategies are proposed to suppress both slip and chatter frequently occurring in the actual rolling process.

关键词： Cold tandem rolling:Oil film thickness Speed-dependent friction coefficient-Slip:Chatter

Inhibiting shuttle effect of lithium polysulfides by double metal selenides for high-performance lithium-sulfur batteries

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Rare Metals 2024年第6期43卷 2546-2559页

作者： Lei li Xue-Jing Yang Yi-Yang li bo Jin Hui liu Meng-Yang Cui Dong-bo Guan Xing-You Lang qing Jiang Key Laboratory of Automobile Materials Ministry of Educationand College of Materials Science and EngineeringJilin UniversityChangchun 130022China

lithium-sulfur batteries(LSBs)have attracted the attention of more and more researchers due to the advantages of high energy density,environmental friendliness,and low production ***,the low electronic conductivity of active material and shuttling effect of lithium polysulfides(liPSs)limit the commercial development of *** solve these problems,we design a core-shell composite with nitrogen-doped carbon(NC)and two types of selenides(FeSe_(2)-NC@ZnSe-NC).The FeSe_(2)-NC@ZnSe-NC has a strong adsorption capacity,and can effectively adsorb *** the same time,it also effectively alleviates the shuttling effect of liPSs,and improves the utilization of the active substance during the charge/discharge reaction *** mechanism involved in FeSe_(2)-NC@ZnSe-NC is demonstrated by both experiments and density-functional theory(DFT)*** electrochemical test results indicate that LSB with S/FeSe_(2)-NC@ZnSe-NC delivers an initial discharge capacity of 1260 mAh·g^(-1)at *** after 500 cycles at 1C,the capacity decay rate per cycle is 0.031%,and the capacity retention rate is 85%.The FeSe_(2)-NC@ZnSe-NC core-shell structure verifies a rational strategy to construct an electrode material for high-performance LSBs.

关键词： lithium-sulfur batteries Shuttling effect Metal selenide Nitrogen-doped carbon lithium polysulfides

Enhanced hydrogen evolution reaction in FePt film with remanence due to decrease in domain walls

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Rare Metals 2024年第3期43卷 1108-1115页

作者： Hong Hong Dong-Xue liu Jun li Jun-Ming li li-Qian Wu bo Yang qing-Qi Cao Dun-Hui Wang National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced MicrostructuresJiangsu Provincial Key Laboratory for NanotechnologySchool of PhysicsNanjing UniversityNanjing210093China Hangzhou Dianzi University Hangzhou310018China Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Material Science and EngineeringNortheastern UniversityShenyang110819China

As an effective strategy to improve the properties of electrocatalysts,magnetic field-assisted electrocatalytic water splitting has attracted increasing attention ***,the corresponding enhancements mostly depend on the exertion of an external magnetic field during electrochemical reactions,which results in a high cost of industrial production,and makes the magnetic field manipulation of electrocatalysis become a challenging *** this work,instead of the external magnetic field,a bias magnetic field is self-supplied by the remanence state of a ferromagnetic electrocatalyst of *** to the assistance of this bias magnetic field,the FePt film in the remanence state shows the overpotential of 229 mV during hydrogen evolution reaction,which is much lower than that in its demagnetization state(283 mV).Our findings demonstrate that the remanence in ferromagnetic electrocatalysts can improve the catalytic performance,which is attributed to the decrease in domain walls.

关键词： Remanence Magnetic domains Electrocatalysis Hydrogen evolution reaction(HER)

Numerical simulation of melt flow and temperature field during DC casting 2024 aluminium alloy under different casting conditions

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China Foundry 2024年第4期21卷 387-396页

作者： Jin-chuan Wang Yu-bo Zuo qing-feng Zhu Jing li Rui Wang Xu-dong liu Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Engineering Research Center of Advanced Materials Preparing Technology Ministry of EducationShenyang 110819China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Casting speed,casting temperature and secondary cooling water flow rate are the main process parameters affecting the DC casting *** parameters significantly influence the flow and temperature fields during casting,which are crucial for the quality of the ingot and can determine the success or failure of the casting *** simulation,with the advantages of low cost,rapid execution,and visualized results,is an important method to study and optimize the DC casting *** the present work,a simulation model of DC casting 2024 aluminum alloy was established,and the reliability of the model was ***,the influence of casting parameters on flow field and temperature field was studied in detail by numerical simulation *** show that with the increase of casting speed,the melt flow becomes faster,the depths of slurry zone and mushy zone increase,and the variation of slurry zone depth is greater than that of mushy *** an increase in casting temperature,the melt flow rate increases,the depth of the slurry zone becomes shallower,and the depth of the mushy zone experiences only minor *** simulation results further indicate that the increase of the flow rate of the secondary cooling water slightly reduces the depths of both slurry and mushy zone.

关键词： aluminium DC casting flow field temperature field numerical simulation

Enhanced Sensing Mechanism Based on Shifting an Exceptional Point

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Research 2024年第3期6卷 285-292页

作者： Xuan Mao Guo-qing Qin Hao Zhang bo-Yang Wang Dan Long Gui-Qin li Gui-Lu Long Department of Physics State Key Laboratory of Low-Dimensional Quantum PhysicsTsinghua UniversityBeijing 100084China Beijing Institute of Radio Measurement The Second Academy of China Aerospace Science and Industry Corporation(CASIC)Beijing 100854China Purple Mountain Laboratories Nanjing 21111China Frontier Science Center for Quantum Information Beijing 100084China Beijing Academy of Quantum Information Sciences Beijing 100193China

Non-Hermitian systems associated with exceptional points (EPs) are expected to demonstrate a giant response enhancement for various sensors. The widely investigated enhancement mechanism based on diverging from an EP should destroy the EP and further limits its applications for multiple sensing scenarios in a time sequence. To break the above limit, here, we proposed a new enhanced sensing mechanism based on shifting an EP. Different from the mechanism of diverging from an EP, our scheme is an EP nondemolition and the giant enhancement of response is acquired by a slight shift of the EP along the parameter axis induced by perturbation. The new sensing mechanism can promise the most effective response enhancement for all sensors in the case of multiple sensing in a time sequence. To verify our sensing mechanism, we construct a mass sensor and a gyroscope with concrete physical implementations. Our work will deepen the understanding of EP-based sensing and inspire designing various high-sensitivity sensors in different physical systems.

关键词： mechanism shifting exceptional

Low Concentration of Wenyang Tonglin Decoction Promotes Conjugation and Transfer of Drug-Resistant Plasmids among Heterologous Strains

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Chinese Journal of Integrative Medicine 2024年第8期30卷 721-728页

作者： WANG Bi-yan BU Hong-shi XIA li-bo JIANG Xiang-yu TONG Yan-qing Department of Traditional Chinese Medicine Changchun University of Traditional Chinese MedicineChangchun130000China

Objective To investigate the effect of low concentration of Wenyang Tonglin Decoction(WTD)on the binding conditions of R45 plasmid conjugative transfer under liquid phase conjugation and its *** Escherichia coli CP9(R45)and Staphylococcus aureus RN450RF were cultured in medium containing WTD,and their minimum inhibitory concentration(MIC)values were *** promoter fusion technology,*** CP9(R45)containing a promoter fusion was obtained.β-Galactosidase activity of TrfAp and TrbBp was tested,and the mRNA expression of regulatory factors(TrbA,KorA,and KorB)was detected by real-time fluorescent quantitative polymerase chain *** The MIC of *** CP9(R45)was 400 g/L and that of *** RN450RF was 200 g/*** the drug concentration in the culture medium was 200 g/L,the highest number of conjugants was(3.47±0.20)×10^(7) CFU/mL At 90 h of conjugation,the maximum number of conjugants was(1.15±0.06)×10^(8) CFU/mL When the initial bacterial concentration was 10^(8) CFU/mL,the maximum number of conjugants was(3.47±0.20)×10^(7) CFU/*** the drug concentration was 200 g/L,theβ-galactosidase activity of TrfAp and TrbBp significantly increased;the relative quantification of TrbA,KorA and KorB were significantly *** Low concentration of WTD promoted the development of bacterial resistance by affecting promoters and inhibiting the expression of regulatory factors.

关键词： urinary tract infection Chinese medicine drug-resistant plasmid heterozygous strains conjugation transfer

Concurrent hetero-/homo-geneous electrocatalysts to bi-phasically mediate sulfur species for lithium-sulfur batteries

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Journal of Energy Chemistry 2024年第6期93卷 663-668,I0016页

作者： Rui-bo lingHu Jin-Xiu Chen Jin-Hao Zhang bo-Quan li qing-Shan Fu Gulnur Kalimuldina Geng-Zhi Sun Yunhu Han Long Kong Xi’an Institute of Flexible Electronics(IFE) Northwestern Polytechnical UniversityXi’an 710129ShaanxiChina Institute of Advanced Materials Nanjing Tech UniversityNanjing 211816JiangsuChina Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China Department of Mechanical and Aerospace Engineering School of Engineering and Digital SciencesNazarbayev UniversityKabanbay Batyr Ave.53Astana 010000Kazakhstan

Expediting redox kinetics of sulfur species on conductive scaffolds with limited charge accessible surface is considered as an imperative approach to realize energy-dense and power-intensive lithium-sulfur(li-S)*** this work,the concept of concurrent hetero-/homo-geneous electrocatalysts is proposed to simultaneously mediate liquid-solid conversion of lithium polysulfides(liPSs)and solid lithium disulfide/sulfide(li_(2)S_(2)/li_(2)S)propagation,the latter of which suffers from sluggish reduction kinetics due to buried conductive scaffold surface by extensive deposition of li_(2)S_(2)/li_(2)*** selected model material to verify this concept is a two-in-one catalyst:carbon nanotube(CNT)scaffold supported iron-cobalt(Fe-Co)alloy nanoparticles and partially carbonized selenium(C-Se)*** Fe-Co alloy serves as a heterogeneous electrocatalyst to seed li_(2)S_(2)/li_(2)S through sulphifilic active sites,while the C-Se sustainably releases soluble lithium polyselenides and functions as a homogeneous electrocatalyst to propagate li_(2)S_(2)/li_(2)S via solution *** bi-phasic mediation of the sulfur species benefits reduction kinetics of liPS conversion,especially for the massive li_(2)S_(2)/li_(2)S growth scenario by affording an additional solution directed route in case of conductive surface being largely *** strategy endows the li-S batteries with improved cycling stability(836 mA h g^(-1)after 180 cycles),rate capability(547 mA h g^(-1)at 4 C)and high sulfur loading superiority(2.96 mA h cm^(-2)at 2.4 mg cm^(-2)).This work hopes to enlighten the employment of bi-phasic electrocatalysts to dictate liquid-solid transformation of intermediates for conversion chemistry batteries.

关键词： lithium-sulfur batteries Electrocatalysis lithium polysulfides Sulfur cathode Energy density

Recovery of cyanophycin granule polypeptide from activated sludge: carbon source dependence and aggregation-induced luminescence characteristics

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Frontiers of Environmental Science & Engineering 2024年第2期18卷 25-34页

作者： Kui Zou Hongyuan liu bo Feng Taiping qing Peng Zhang College of Environment and Resources Xiangtan UniversityXiangtan 411105China

In the sewage treatment process,facilitating the conversion of pollutants into value-added resources holds great potential for reducing the amount of greenhouse gas emissions and promoting economic *** granule polypeptide(CGP),a recently discovered high value-added biopolymer present in activated sludge,has provided new avenues for the recovery of ***,the mechanisms that regulate CGP synthesis and the characteristics of this biopolymer in activated sludge remain unclear thus *** study investigated the synthesis of CGP,polyhydroxyalkanoates(PHA),and alginate-like exopolysaccharides(ALE)in various microbial aggregates under different carbon sources feeding *** results showed that the CGP yields was superior that of PHA and ALE when subjected to identical carbon source feeding ***,biofilm was more conducive to CGP accumulation than floc *** with glucose and methanol,sodium acetate significantly enriched the CGP synthetase-encoding gene(cphAabundance=~17419),resulting in the highest CGP yield(average 107.1 mg/g MLSS)in both biofilm and floc *** study is the first to reported the characteristic fluorescence of CGP(Ex/Em=~360/450 nm)caused by the aggregated luminescence of arginine on the side ***,this study highlights the potential application of CGP as a fluorescent material and offers insights into CGP recovery from activated sludge in wastewater treatment plants.

关键词： Cyanophycin Polyhydroxyalkanoate Alginate-like exopolysaccharides Bioresource recovery Aggregation-induced luminescence

Competitive assembling strategy to construct carbon nitride homojunctions for boosting photocatalytic performance

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Journal of Materials Science & Technology 2024年第5期172卷 23-32页

作者： Hua-Wei Zhang Yuan-Yuan li bo li Jing-Hui Shi Tao Huang Gui-Fang Huang Anlian Pan Wangyu Hu Wei-qing Huang School of Physics&Electronic Engineering Zhengzhou University of Light IndustryZhengzhou 450002China Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China College of Materials Science and Engineering Hunan UniversityChangsha 410082China

both morphology and composition have a great influence on the properties and functions of materials,however,how to rational modulate both of them to achieve their synergistic effects has been a longstanding ***,we demonstrate a competitive assembling strategy for the construction of metal-free graphite carbon nitride(CN)homojunctions in which morphology and composition can be easily controlled simultaneously by only changing the ratio of assembly raw *** homojunctions are comprised of porous nanotubular S-doped CN(SCN)grafted with CN nanovesicles,which are derived from thermal polycondensation of melamine-thiocyanuric acid(M-T)/melamine-cyanuric acid(M-C)supramolecular hybrid *** unique architecture and component engineering endows the novel SCN-CN homojunction with abundant active sites,enhanced visible trapping ability,and intimate interface *** a result,the synthesized SCN-CN homojunctions demonstrate high photocatalytic activity for hydrogen evolution and pollutant *** developed strategy opens up intriguing opportu-nities for the rational construction of intricate metal-free heterostructures with controllable architecture and interfacial contact for applications in energy-related fields.

关键词： Competitive assembling strategy Supramolecular hybrid blocks Homojunctions Graphite carbon nitride Photocatalytic