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Tribological behaviors of graphene oxide partly substituted with nano-SiO_(2) as lubricant additives in water for magnesium alloy/steel interfaces

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International Journal of Minerals,Metallurgy and Materials 2022年第7期29卷 1425-1434页

作者： Hongmei Xie Jiahong Dai dan zhou College of Materials Science and Engineering Yangtze Normal UniversityChongqing 408100China Loncin Industry Chongqing 400052China

Although graphene oxide(GO)has emerged as an excellent lubricant additive in water,there remain great challenges in their practical application due to high production *** taking into account the low cost and also its excellent tribological properties,it is likely that nano-SiO_(2)can be used as a lubricant additive to partially replace ***,this paper aims to explore the tribological properties of nano-SiO_(2)incorporated in GO nanofluids for partial GO replacement by investigating the friction coefficient and wear volume of the prepared SiO_(2)/GO hybrid nanofluids for magnesium alloy/steel sliding *** experiments reveal that the SiO_(2)/GO hybrids retain low friction coefficients as compared to individual GO or SiO_(2)at all test conditions in this ***,as for the bearing capacity test,all samples can provide a low wear volume under the loads of 1 and 3 *** the increase of the normal load,there is considerable differences in the anti-wear *** with that of individual GO nanofluids,the wear volume of the GO/SiO_(2)(mass ratio of 0.3:0.2)hybrid nanofluids was reduced by50.5%at 5 N and by 49.2%at 8 ***,the wear volume of the GO/SiO_(2)(mass ratio of 0.3:0.2)hybrid nanofluids was reduced by46.3%under the rigorous conditions,as compared to individual GO *** findings provide new insights into developing carbon nanomaterial-based hybrid nanofluids for magnesium alloy formation.

关键词： magnesium alloy graphene oxide and nano-silicon dioxide water-based lubricant additive tribological characteristics

The Effect of Concave Size on the Aerodynamics of a Maglev Train

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Journal of Bionic Engineering 2022年第3期19卷 709-723页

作者： Shuang Meng dan zhou Changda Tan Key Laboratory of Traffic Safety on Track(Central South University) Ministry of EducationChangsha410075China Joint International Research Laboratory of Key Technology for Rail Traffic Safety Changsha410075China National and Local Joint Engineering Research Center of Safety Technology for Rail Vehicle Changsha410075China

Inspired by shark’s skin in nature,a non-smooth surface could be an ideal model for changing the flow characteristics of fluids on the object *** analyze the effect of a non-smooth surface with concaves on the maglev train aerodynamic performances and to investigate how the concave size affects the aerodynamic forces and flow structure of a maglev train,four 1/10th scaled maglev train models are simulated using an Improved Delayed Detached Eddy Simulation(IDDES)*** numerical strategy used in this study is verified by comparison with the wind tunnel test results,and the comparison shows that the difference was in a reasonable *** results demonstrate that the concaves could effectively reduce the tail car pressure drag,thus reducing the total drag,and that the smaller the concave size was,the better the drag reduction effect would *** change in the lift with the concave size was more significant than that of the drag,and the tail car lift of R1(0.0012H),R2(0.0024H),and R3(0.0036H)train models was 30.1%,43.0%,and 44.5%less than that of the prototype,*** addition,different flow topologies of the wake are *** width and height of the vortex core of the counter-rotating vortices tended to decrease with the concave ***,from the point of view of ensuring the operating safety of a maglev train,a non-smooth surface with small-size concaves is recommended.

关键词： Maglev train Aerodynamic characteristics Concave Numerical simulation

PV Array Reconfiguration Based on the Shaded Cells'Number for PV Modules

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CSEE Journal of Power and Energy Systems 2023年第2期9卷 733-742页

作者： Jun Qi Xun Huang Beijia Ye dan zhou College of Information Engineering Zhejiang University of TechnologyHangzhou 310014China

Reconfiguration can increase the output power for a PV array under partial ***,traditional reconfiguration methods consider the PV module as either totally shaded or totally unshaded,and module-based simulation is employed to evaluate the reconfiguration ***,there is an unneglectable error when treating a partially shaded PV module as totally shaded,through using a more accurate cellbased *** on the analysis of the determinant factors on MPPs’power of a PV array,a new reconfiguration method is proposed based on the exact partial shadow shape projected on the PV *** method restructures the electrical connection among PV modules of a PV array according to the shaded cells’number(SCN)of every PV *** cell-based simulations are carried out on a PV array to verify the effectiveness of the proposed SCN-based reconfiguration *** comparisons among various reconfiguration methods and shadow distributions clearly show its suitability to different irregular shadows and its superiority in PV output power enhancement.

关键词： Maximum power point(MPP) partial shadow PV array PV module reconfiguration

A robust solid electrolyte interphase enabled by solvate ionic liquid for high-performance sulfide-based all-solid-state lithium metal batteries

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Nano Research 2023年第6期16卷 8411-8416页

作者： Jingguang Yi Chong Yan dan zhou Li-Zhen Fan Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China School of electrical engineering and automation Luoyang Institute of Science and TechnologyLuoyang 471023China Shanxi Research Institute for Clean Energy Tsinghua UniversityTaiyuan 030032China

All-solid-state lithium metal batteries(ASSLMBs)that incorporate solid electrolyte(SE)and lithium metal anode suggest considerable potential in addressing the security concerns and energy density limitation of conventional lithium-ion batteries(LIBs).However,the practical application of ASSLMBs is always restricted by the interfacial instability of lithium metal anode/electrolyte and inevitable lithium dendrites propagation in ***,a solvate ionic liquid is adopted to modify the interface stability of lithium metal anode/electrolyte and inhibit the growth of lithium dendrites via an in-situ formation of a robust solid electrolyte interphase(SEI)on the surface of lithium metal ***,the ASSLMBs assembled with Li_(6)PS_(5)Cl(LPSCl)electrolyte,lithium metal anode that protected by robust SEI layer,and LiNbO_(3)@NCM622 cathode exhibit high initial capacity of 126.5 mAh·g^(−1)and improved cycling stability with a capacity retention of 80.3%over 60 cycles at 0.1 *** work helps to provide a facile route for the design of robust SEI in the application of ASSLMBs.

关键词： all-solid-state lithium metal batteries solvate ionic liquid robust solid electrolyte interphase Li_(6)PS_(5)Cl(LPSCl)electrolyte

DNA G-quadruplex and its potential as anticancer drug target

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Science China Chemistry 2014年第12期57卷 1605-1614页

作者： ONEL Buket LIN Clement YANG dan zhou Department of Chemistry and Biochemistry University of Arizona Department of Pharmacology and Toxicology University of Arizona BIO5 Institute University of Arizona The Arizona Cancer Center

G-quadruplex secondary structures are four-stranded globular nucleic acid structures form in the specific DNA and RNA G-rich sequences with biological significance such as human telomeres,oncogene-promoter regions,replication initiation sites,and 5′and 3′-untranslated(UTR)*** non-canonical G-quadruplex secondary structures can readily form under physiologically relevant ionic conditions and are considered to be new molecular target for cancer *** review discusses the essential progress in our lab related to the structures and functions of biologically relevant DNA G-quadruplexes in human gene promoters and telomeres,and the opportunities presented for the development of G-quadruplex-targeted smallmolecule drugs.

关键词： DNA G-quadruplexes oncogene promoters human telomeres G-quadruplex-targeted small molecules anticancer drug target

Numerical study of the influence of dome shape on the unsteady aerodynamic performance of a high-speed train's pantograph subjected to crosswind

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Journal of Traffic and Transportation Engineering(English Edition) 2023年第1期10卷 13-30页

作者： Xiaofang Li dan zhou Lirong Jia Mingzhi Yang Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic and Transportation EngineeringCentral South UniversityChangsha 410075China Joint International Research Laboratory of Key Technology for Rail Traffic Safety Central South UniversityChangsha 410075China National&Local Joint Engineering Research Center of Safety Technology for Rail Vehicle Central South UniversityChangsha 410075China CSR Qingdao Sifang Co.Ltd. Qingdao 266111China

This study aims to investigate the unsteady aerodynamic performance of a high-speed train’s pantograph with respect to two different dome shapes and without dome under a20°yaw angle using a delayed detached eddy simulation ***,the influence of the dome shape on the simulation results is *** accuracy of the numerical method was validated by comparing a few of the numerical results with the wind tunnel test results,and high consistency was *** analysis of aerodynamic forces and flow structures around the pantograph was *** dome had significant influence on velocity field distribution surrounding the pantograph,particularly in the wake of flow *** with the case where the dome was absent,vortex intensity around the pantograph increased after installing the *** existence of the bathtub-type dome resulted in greater flow field disturbance and vortex strength than the baffle-type ***,the dome considerably affected time-averaged aerodynamic coefficients and their fluctuations,especially the bathtub-type ***,the power spectral density of the unsteady aerodynamic coefficient of each pantograph component exhibited significant peaks and typical broadband distribution characteristics.

关键词： High-speed train Crosswind Pantograph Dome Unsteady aerodynamic performance

Experimental Study on the Reduction Effect of Pit Texture on Disassembly Damage for Interference Fit

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Chinese Journal of Mechanical Engineering 2023年第2期36卷 249-260页

作者： dan zhou Yi Xu Xin Gao Haihong Huang Songjiang Lv Key Laboratory of Green Design and Manufacturing in Machinery Industry Hefei University of TechnologyHefei 230009China CRRC Nanjing Puzhen Co.Ltd Nanjing 210031China

After remanufacturing disassembly,several kinds of friction damages can be found on the mating surface of interference *** damages should be repaired and the cost is closely related to the severity of *** by the excellent performance of surface texture in wear reduction,5 shapes of pit array textures are added to the specimens’surface to study their reduction effect of disassembly damage for interference *** results of disassembly experiments show that the order of influence of texture parameters on disassembly damage is as follows:equivalent circle diameter of single texture,texture shape and texture surface *** influence of equivalent circle diameter of single texture and texture shape are obviously more significant than that of texture surface *** circular texture with a surface density of 30%and a diameter of 100μm shows an excellent disassembly damage reduction effect because of its perfect ability of abrasive particle *** the probability of disassembly damage formation and evolution is also relatively small on this kind of textured ***,the load-carrying capacity of interference fit with the excellent texture is confirmed by load-carrying capacity *** results show that the load-carrying capacity of the excellent texture surface is increased about 40%compared with that of without *** research provides a potential approach to reduce disassembly damage for interference fit.

关键词： Remanufacturing Interference fit Disassembly damage Surface texture Load-carrying capacity

Intelligently assembly of W_(18)O_(49)nanorod clusters with directionally generated oxygen vacancies and excellent electrochemical properties

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Nano Research 2022年第4期15卷 3575-3586页

作者： dan zhou Xiaojiao Guo Yixiang Chen Xiaoyu Yuan Jinku Liu Key Laboratory for Advanced Materials School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Mixed-valence metallic compounds are a class of functional materials with peculiar electrochemical *** the correlation between defects and corrosion resistance of mixed-valence metallic compounds is a novel and interesting *** an intelligently designed synergistic process of reduction and directed assembly,not only the directional generation of oxygen vacancies along the normal direction of the(010)crystal plane was achieved,but also the W_(18)O_(49)mixed-valence metal oxide(MVMO)with a single crystalline phase and an assembled ordered three-dimensional cluster structure of nanorods was *** attractive effects of oriented oxygen vacancies in W_(18)O_(49)MVMO were ***,the oxygen vacancy channels realized the directional concentrated transport of oxygen atoms to form dense oxide passivation ***,the directional concentrated oxygen vacancies as active centers effectively solved the problem of difficult photoelectron leap and separation of pure-phase semiconductors,realizing photogenerated cathodic ***,the high-energy vacancies endowed the material with antibacterial function,which contributed to the stable existence of the anti-corrosion *** resistance value of W_(18)O_(49)MVMO as an anti-corrosion functional material was increased to more than 4.00 times that of the original metal protection *** experimental results obtained in this research were of great reference value for revealing the intrinsic mechanism of correlation between oxygen defect orientation of MVMOs and electrochemistry.

关键词： oxygen vacancy directional generated W_(18)O_(49) mixed-valence metal oxide electrochemical properties

Unified Residue Method for Design of Compact Wide-area Damping Controller Based on Power System Stabilizer

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Journal of Modern Power Systems and Clean Energy 2020年第2期8卷 367-376页

作者： Jun Qi Qian Wu Youbing Zhang Guoqing Weng dan zhou the College of Information Engineering Zhejiang University of TechnologyHangzhou 310023China

A wide-area damping controller(WADC)is effective in damping inter-area low-frequency oscillation(LFO),if the time delay in a wide-area control loop can be properly *** order to simplify the WADC design and enlarge the delay adaptation range,the classic power system stabilizer(PSS)is adopted,and a new unified residue(UR)method is proposed for compact WADC *** strategy of control loop selection is also improved by modifying the relative residue index based on a few dominant oscillation *** designed PSSbased compact WADC is as simple as classic PSS with no more than two lead-lag phase compensation *** studies are carried out on an IEEE 16-machine 68-bus power *** results demonstrate that the control loop selection before the WADC design is necessary and that the proposed selection strategy can easily pick out the suitable candidate control *** addition,it is feasible for the UR method to design WADCs with different time delays in the selected control *** the designed WADCs are effective in damping inter-area LFO and robust to time delay variations under operation *** among five design methods for PSS-based WADC show that the proposed UR method is superior in delay adaptation,the conciseness of WADC structure and computation speed of parameters.

关键词： Wide-area measurement system(WAMS) time delay wide-area damping controller(WADC) power system stabilizer(PSS)