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Ultralow friction PTFE/PEEK heterolayer:A new solid lubrication approach toward simplicity

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Friction 2024年第1期12卷 120-135页

作者： Wei SUN Jiaxin YE Qingrui SONG Yi FENG Xiaojun LIU School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Institute of Tribology School of Mechanical EngineeringHefei University of TechnologyHefei 230009China

Tribological applications of polytetrafluoroethylene(PTFE)are often limited by technological complexity to overcome its poor wear ***,a PTFE/polyetheretherketone(PEEK)heterolayer(HL)was proposed and evaluated as a new solid lubrication ***-on-disk tribometry found the lowest friction coefficient(μ)of 0.031 and ultralow wear for the PEEK/HL under typical *** friction coefficient of the HL surpasses those of the state-of-the-art polymeric coatings/composites by at least 200%,and approaches that of highly lubricated *** investigations revealed multi-length physical and chemical heterogeneity of the HL that best facilitates a tribofilm with high subsurface stability and surface *** technological simplicity and robustness of the HL’s high lubricity make it a promising new type of solid lubrication toward greater reliability and longevity.

关键词： ultralow friction anti-wear polytetrafluoroethylene(PTFE) heterolayer(HL)

CFD-DEM study of impacts of the porous distributor medium on fluidization characteristics of a 2D-fluidized bed

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Particuology 2024年第4期87卷 54-73页

作者： Fei Wang Yishan Zeng Hao Yan School of Mechanical Engineering Hefei University of TechnologyHefei230009China

Gas-solid bubbling fluidized beds are widely used in chemical,energy,construction,and other industrial fields due to their excellent fluidization performance.2D-fluidized beds with planar rectangular columns of finite thickness are widely used in fluidized bed studies,and it is essential for understanding the hydrodynamics of gas-particle ***,the distributor(porous medium)at the bottom of the bed has a crucial influence on the fluidization performance of the 2D-fluidized *** this work,the fluidization mechanism and gas-solid dynamic characteristics of the fluidized bed under three porous media are studied by CFD-DEM coupled with the porous medium model,and the accuracy of numerical simulation is verified by a high-speed photography *** show that with the increase in the flow resistance of the porous medium,the average and standard deviation of the bubble diameter decrease,and the time and position of particles in the dead zone to participate in the core-annular flow *** a low fluidization velocity,the dead zone in the bed can be considerably reduced by increasing the flow resistance.

关键词： Fluidized bed CFD-DEM Porous medium Bubble dynamics Solid mixing

Detection accuracy of target accelerations based on vortex electromagnetic wave in keyhole space

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Chinese Physics B 2024年第2期33卷 283-290页

作者：郭凯雷爽雷艺周红平郭忠义 School of Computer and Information Hefei University of TechnologyHefei 230009China

The influence of the longitudinal acceleration and the angular acceleration of detecting target based on vortex electromagnetic waves in keyhole space are *** spectrum spreads of different orbital angular momentum(OAM)modes in different non-line-of-sight situations are *** errors of target accelerations in detection are calculated and compared based on the OAM spectra spreading by using two combinations of composite OAM modes in the keyhole *** to the research,the effects about spectrum spreads of higher OAM modes are more *** error in detection is mainly affected by OAM spectrum spreading,which can be reduced by reasonably using different combinations of OAM modes in different practical *** above results provide a reference idea for investigating keyhole effect when vortex electromagnetic wave is used to detect accelerations.

关键词： vortex electromagnetic waves detect accelerations keyhole space spectrum spread

Distributed Cooperative Secondary Voltage Control in an Unbalanced Microgrid

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 222-234页

作者： Xiangzhen Yang Haixi Zhao Mengke Duan Yan Du Haining Wang Jian Zhang School of Electrical Engineering and Automation Hefei University of TechnologyHefei 23009China

The negative-sequence reactive power-conductance(Q^(−)-G) droop control strategy is a conventional method to compensate for the output unbalanced voltages in an islanded ***, the conflict between unbalanced voltage compensation and negative-sequence reactive power sharing, caused bythe impedance mismatching of distribution lines and distributedgenerators, has not been solved only by Q^(−)-G droop *** this paper, a distributed cooperative secondary unbalancedvoltage control strategy is proposed to decrease the outputvoltage unbalance factor (VUF) of each droop-controlled DG,as well as to further enhance the negative-sequence reactivepower sharing effectiveness among DGs by properly shiftingup and down the Q^(−)-G droop characteristics of each *** algorithm for adaptive VUF weight coefficient is proposedto better suppress VUF under severe imbalance ***, a negative-sequence small-signal model of an MGunder an unbalanced condition, considering the communicationdelay time of the proposed SUVC, is established to analyze thesystem’s stability and transient performance under the influenceof some critical parameters. Finally, the effectiveness of theproposed strategy is validated by the simulation results froma real-time emulator of StarSim HIL.

关键词： Distributed cooperative control MG negativesequence reactive power starsim real-time platform time delay voltage unbalance compensation

Effect of Bimodal Quasicrystal Phase on the Dynamic Recrystallization of Mg–Zn–Gd Alloy during High-Pressure Torsion

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Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1128-1134页

作者： Ping Li Shuangwu Xia Junfu Dong Liangwei Dai Zhicheng Luo Kemin Xue School of Material Science and Engineering Hefei University of TechnologyHefei230009China

The Mg–Zn–Gd alloy with quasicrystal icosahedral phase was processed by high-pressure torsion (HPT). The effect of bimodal I-phase on the dynamic recrystallization was analyzed by transmission electron microscopy. The results showed that the block I-phase can stimulate obvious particle-stimulated nucleation and dynamic recrystallization (DRX) grains were preferentially formed after HPT for 5 turns, while the granular I-phase only promoted the generation of sub-grains. The orientation relationship was determined as twofold//[1210] and fivefold//(0002)_(Mg). Moreover, after HPT for 9 turns, the DRX grains induced by block I-phase appeared to grow up and coarsened. Compared with block I-phase, the grains induced by granular I-phase presented much smaller size and distributed more homogeneous due to the strong pinning effect.

关键词： High-pressure torsion(HPT)-Quasicrystal phase Dynamic recrystallization Particle-stimulated nucleation Orientation relationship

Neutron irradiation influence on high-power thyristor device under fusion environment

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Nuclear Science and Techniques 2024年第4期35卷 65-81页

作者： Wei Tong Hua Li Meng Xu Zhi-Quan Song Bo Chen School of Electrical Engineering and Automation Hefei University of TechnologyHefei 230009China Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China university of Science and technology of China Hefei 230026China

Because of their economy and applicability,high-power thyristor devices are widely used in the power supply systems for large fusion *** high-dose neutrons produced by deuterium–tritium(D–T)fusion reactions are irradiated on a thyristor device for a long time,the electrical characteristics of the device change,which may eventually cause irreversible *** this study,with the thyristor switch of the commutation circuit in the quench protection system(QPS)of a fusion device as the study object,the relationship between the internal physical structure and external electrical parameters of the irradiated thyristor is ***,a series of targeted thyristor physical simulations and neutron irradiation experiments are conducted to verify the accuracy of the theoretical *** addition,the effect of irradiated thyristor electrical characteristic changes on the entire QPS is studied by accurate simulation,providing valuable guidelines for the maintenance and renovation of the QPS.

关键词： Fusion device Neutron irradiation effects Thyristor Quench protection

Classical spin liquid state in a rhombic lattice metal-organic framework

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Nano Research 2024年第4期17卷 3407-3412页

作者： Sihua Feng Chao Wang Jiyin Zhao Xuguang Liu Chaocheng Liu Zeming Qi Lei Chen Huijuan Wang Minghui Fan Hengli Duan Wensheng Yan National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230026China hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Experimental Center of Engineering and Material Science University of Science and Technology of ChinaHefei 230026China

Discovering more and new geometrically frustrated systems remains an active point of inquiry in fundamental physics for the existence of unusual states of ***,we report spin-liquid-like behavior in a two-dimensional(2D)rhombic lattice Fe-metal-organic framework(Fe-MOF)with frustrated *** Fe-MOF exhibits a high frustration factor f=|θCW|/TN≥315,and its long-range magnetic order is suppressed down to 180 *** theoretical calculations demonstrate strong antiferromagnetic coupling between adjacent Fe3+ions,indicating the potential of a classical spin-liquid-like ***,a T-linear heat capacity parameter,γ,originating from electronic contributions and with magnetic field independence up to 8 T,can be observed in the specific heat capacity measurements at low-temperature,providing further proof for the spin-liquid-like *** work highlights the potential of MOF materials in geometrically frustrated systems,and will promote the research of exotic quantum physics phenomena.

关键词： spin-liquid-like state two-dimensional metal-organic framework(2D MOF) rhombic lattice ultralow temperature(ULT)measurements spin-frustrated

Deep Reinforcement Learning Based Resource Allocation for Fault Detection with Cloud Edge Collaboration in Smart Grid

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1220-1230页

作者： Qiyue Li Yadong Zhu Jinjin Ding Weitao Li Wei Sun Lijian Ding hefei university of technology Engineering technology Research Center of Industrial Automation Hefei 230009China Electric Power Research Institute of State Grid Anhui Electric Power Co. Ltd.Hefei 230000China hefei university of technology Hefei 230009China IEEE CSEE

Real-time fault detection is important for operation of smart *** has become a trend of future development to design an anomaly detection system based on deep learning by using the powerful computing power of the ***,delay of Internet transmission is large,which may make the delay time of detection and transmission go beyond the ***,the edge-based scheme may not be able to undertake all data detection tasks due to limited computing resources of edge ***,we propose a cloud-edge collaborative smart grid fault detection system,next to which edge devices are placed,and equipped with a lightweight neural network with different precision for fault *** addition,a sub-optimal and realtime communication and computing resource allocation method is proposed based on deep reinforcement *** method greatly speeds up solution time,which can meet the requirements of data transmission delay,maximize the system throughput,and improve communication *** results show the scheme is superior in transmission delay and improves real-time performance of the smart grid detection system.

关键词： Cloud-edge collaboration communication delay deep reinforcement learning fault detection smart grid

Structural characterization of three acidic polysaccharides from Opuntia dillenii *** and their protective effect against hydrogen peroxide-induced oxidative stress in Huh-7 cells

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Food Science and Human Wellness 2024年第4期13卷 1929-1942页

作者： Rui Liu Fangxin Chu Zheng Yan Hanqing Chen School of Food and Biological Engineering Hefei University of TechnologyHefei 230601China Engineering Research Center of Bio-Process Ministry of EducationHefei University of TechnologyHefei 230601China

Three novel acidic polysaccharide fractions(OFPP-1,OFPP-2,OFPP-3)with different m olecular weights(803.7,555.1 and 414.5 k Da)were isolated from the peeled Opuntia dillenii *** by alkali-extraction,graded alcohol precipitation and column *** analysis indicated that OFPPs were pectic polysaccharides consisting of rhamnose,arabinose and galactose *** backbone of OFPP-1 consisted of a repeating unit→6-α-D-Galp A-(1→2)-α-L-Rhap-(1→with T-α-D-Galp A-(1→6)-α-D-Galp A-(1→4)-α-D-Glcp-(1→,T-β-D-Xylp-(1→6)-α-D-Galp A-(1→4)-α-D-Glcp-(1→or T-α-D-Galp A-(1→3)-α-L-Araf-(1→as the side *** backbone of OFPP-2 consisted of a disaccharide repeating unit→2)-α-L-Rhap-(1→4)-β-D-Galp A-(1→with T-β-L-Araf-(1→as the branches substituted at the O-4 position of→2,4)-α-LRhap-(1→.Whereas the backbone of OFPP-3 was→2,4)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-β-L-Araf-(1→or→2,4)-α-L-Rhap-(1→2)-α-L-Rhap-(1→4)-β-D-Galp A-(1→,which was branched at the O-4 position of→2,4)-α-L-Rhap-(1→.Moreover,these three polysaccharide fractions could protect Huh-7 cells against H2O2-induced oxidative stress to different extents by decreasing the MDA content and increasing the SOD,CAT,GSH-Px activities and the GSH level in the Huh-7 *** results suggest that OFPPs have the potential to be used as natural antioxidants.

关键词： Opuntia dillenii Haw.fruits Polysaccharide Alkali extraction Structural characterization Oxidative stress