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The action mechanism of the work done by the electric field force on moving charges to stimulate the emergence of carrier generation/recombination in a PN junction

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1001-1014页

作者： Lingyun GUO Yizhan YANG Wanli YANG Yuantai HU Department of Mechanics School of Aerospace EngineeringHubei Key Laboratory of Engineering Structural Analysis and Safety AssessmentHuazhong University of Science and TechnologyWuhan 430074China

It is discovered that the product of the current and the electric field in a PN junction should be regarded as the rate of work(power)done by the electric field force on moving charges(hole current and electron current),which was previously misinterpreted as solely a Joule heating *** clarify that it is exactly the work done by the electric field force on the moving charges to stimulate the emergence of non-equilibrium carriers,which triggers the novel physical *** regards to Joule heat,we point out that it should be calculated from Ohm’s law,rather than simply from the product of the current and the electric *** on this understanding,we conduct thorough discussion on the role of the electric field force in the process of carrier recombination and carrier *** thermal effects of carrier recombination and carrier generation followed are incorporated into the thermal equation of *** present study shows that the exothermic effect of carrier recombination leads to a temperature rise at the PN interface,while the endothermic effect of carrier generation causes a temperature reduction at the *** two opposite effects cause opposite heat flow directions in the PN junction under forward and backward bias voltages,highlighting the significance of managing device heating phenomena in design ***,this study possesses referential significance for the design and tuning on the performance of piezotronic devices.

关键词： piezoelectric semiconductor(PS) work done by electric field force thermal effect piezotronic device resistivity conductivity

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Interaction of yttrium barrier and calcium-rich phase on production and properties of WC precursor powders and alloys

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Journal of Rare Earths 2024年第1期42卷 228-236,I0008页

作者： Wen He Dunqiang Tan Zhiqiang Yi Zhiqiang Liu School of Materials science and engineering Nanchang UniversityNanchang330031China Instrumental analysis Center of Nanchang Hangkong University Nanchang330063China

In order to reduce or eliminate the adverse effects of calcium impurity,the interaction of Ca and rare earth Y co-doping on the preparation of WC-Co cemented carbides was investigated.X-ray diffraction,scanning electron microscopy and transmission electron microscopy were employed to analyze the phase compositions,particle sizes and morphologies of them,*** results show that the second type of"yttrium barrier effect"is observed and the adverse influence of Ca-rich phase on tungsten powder can be eliminated by *** flexural strength and fracture toughness of YG6-0.01%Ca+0.09%Y alloy are 2199.5 MPa and 11.49 MPa·m^(1/2),showing improvement of 6.5% and 2.7% compared to YG6 alloy,*** evolutions of Ca-rich phase and Y-rich phase at the every alloy preparation stage of WO_(3),W,WC and cemented carbides are ***,the strengthening mechanism of WC-Co cemented carbide with co-addition of Ca and Y is proposed.

关键词： Yttrium barrier effect Ca-rich phase WC-Co cemented Carbide Microstructures Mechanisms Rare earths

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Mathematical model and numerical investigation of the influence of spray drying parameters on granule sizes of mold powder

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Particuology 2024年第2期85卷 280-295页

作者： Fei Zhang Youyu Lu Shaoyan Zhu Funian Han Guanghua Wen Ping Tang Zibing Hou College of Materials science and engineering Chongqing UniversityChongqing400044China Guizhou Academy of Testing and analysis Guizhou Academy of SciencesGuiyang550014China

In this work,the formation mechanism of the droplet-to-granule was investigated in detail based on mold powder manufacturing.A specific mathematical model of two-stage spray drying was established to describe droplet and granule motion,heat and mass transfer,and granule morphology during spray ***,the relationships between spray drying parameters(inlet temperature,atomization pres-sure,slurry mass flow rate)and the properties of the drying tower(temperature and velocity fields)and mold powder granules(temperature,evaporation rates,moisture content,and diameter)were simulated and calculated using ANSYS/Fluent *** ensure that the granule size of mold powder was controlled within the ideal range(0.2-0.6 mm)for producing granules with appropriate mechanical and metallurgical properties,the following optimum spray drying parameters were chosen based on the results of the numerical simulation:inlet temperatures,873 K;slurry atomization pressure,1.8 MPa;slurry mass flow rate,0.05 kg *** these parameters,the slurry mass flow rate has the most significant effect on granule size.

关键词： Mold powder slurry Spray drying parameters Mathematical model Numerical simulation Granule sizes

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Nonlinear dynamics of a circular curved cantilevered pipe conveying pulsating fluid based on the geometrically exact model

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 261-276页

作者： Runqing CAO Zilong GUO Wei CHEN Huliang DAI Lin WANG Department of engineering Mechanics School of Aerospace EngineeringHuazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory for engineering Structural analysis and Safety Assessment Wuhan 430074China State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Due to the novel applications of flexible pipes conveying fluid in the field of soft robotics and biomedicine,the investigations on the mechanical responses of the pipes have attracted considerable *** fluid-structure interaction(FSI)between the pipe with a curved shape and the time-varying internal fluid flow brings a great challenge to the revelation of the dynamical behaviors of flexible pipes,especially when the pipe is highly flexible and usually undergoes large *** this work,the geometrically exact model(GEM)for a curved cantilevered pipe conveying pulsating fluid is developed based on the extended Hamilton's *** stability of the curved pipe with three different subtended angles is examined with the consideration of steady fluid *** attention is concentrated on the large-deformation resonance of circular pipes conveying pulsating fluid,which is often encountered in practical *** constructing bifurcation diagrams,oscillating shapes,phase portraits,time traces,and Poincarémaps,the dynamic responses of the curved pipe under various system parameters are *** mean flow velocity of the pulsating fluid is chosen to be either subcritical or *** numerical results show that the curved pipe conveying pulsating fluid can exhibit rich dynamical behaviors,including periodic and quasi-periodic *** is also found that the preferred instability type of a cantilevered curved pipe conveying steady fluid is mainly in the flutter of the second *** a moderate value of the mass ratio,however,a third-mode flutter may occur,which is quite different from that of a straight pipe system.

关键词： curved pipe conveying fluid pulsating fluid geometrically exact model(GEM) nonlinear dynamics parametric vibration flutter

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Enzymatic self-assembly/disassembly turns “ON”/“OFF” the mimetic hydrolytic activity of histidine nanofibers

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science China Chemistry 2024年第2期67卷 517-522页

作者： Xianbao Sun Manli Wang Xiaoyang Liu Wenjun Zhan Guangqiong Xu Qiaochu Jiang Hai-Dong Xu Fuqiang Wang Gaolin Liang State Key Laboratory of Digital Medical engineering School of Biological Science and Medical EngineeringSoutheast UniversityNanjing210096China analysis Center Nanjing Medical UniversityNanjing210029China

Mimetic enzymes are devised as alternates or supplements of natural enzymes in broad fields but regulating their activities in a switchable manner remains ***,we proposed an enzymatic self-assembly/disassembly strategy to address this issue.A peptide molecule Nap FFEYIH(YH) was rationally designed which,after self-assembling into nanofibers,lined up the histidine moieties to form active hydrolysis centers for mimicking hydrolase *** dephosphorylation of Nap FFEYp IH(Yp H) by alkaline phosphatase to yield YH also turned “ON” the hydrolase *** turn,phosphorylation of YH by phosphokinase epidermal growth factor receptor to yield Yp H disassembled the nanofibers and thus turned the activity “OFF”.As such,the “ON”/“OFF” of the mimetic hydrolase activities could be regulated under physiological conditions through ALP/EGFR-mediated self-assembly/disassembly of histidine *** work provides a feasible strategy for the on-demand fabrication of artificial enzymes with controllable and superior activities.

关键词： disassembly hydrolytic activity mimetic enzyme phosphorylation self-assembly

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Influence of cerium and yttrium addition on strength and electrical conductivity of pure aluminum alloys

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Journal of Rare Earths 2024年第3期42卷 600-611,I0006页

作者： Guojian Lin Lu Li Zhengwei Guo Xianjun Jia Xiao Wang Zhentao Yuan Guoxing Zhang Yun Zhan Quan Shan Zulai Li Faculty of Materials science and engineering Kunming University of Science and TechnologyKunming650093China Research Center for analysis and Measurement Kunming University of Science and TechnologyKunming650093China City College Kunming University of Science and TechnologyKunming650051China

To develop pure aluminum alloys with high conductivity and strength, Al-0.2Ce and Al-0.2Ce-0.1Y alloys were prepared by rolling and annealing processes in this study. The effects of trace rare earth elements on the strength and electrical conductivity of the pure aluminum alloys were investigated. It is revealed that the addition of Ce and Y to pure aluminum can effectively enhance the strength and electrical conductivity of the alloys. In Al-0.2Ce, the addition of Ce can effectively refine the grain size of a-Al, with an average grain size of 90.68 μm in the as-cast state. The grain size of the alloy is further reduced to 87.55 μm by the simultaneous addition of Y. The synergistic addition of Ce and Y changes the properties of the alloy. The addition of Ce and Y also produces the Al_(11)Ce_(3) and Al_(3)Y second phases, which have coherent relationship with a-Al. The two-dimensional mismatch degree was calculated to be only 4.43%and 0.85%, respectively, which can provide a certain amount of nucleation substrate for a-Al in the incubation stage. The interfacial match between the L1_(2)structure of Al_(3)Y and a-Al was calculated using first-principles simulations. The results indicate that Al_(3)Y has a strong bonding effect with a-Al. Nanoscale second phases at grain boundaries can be effective in reducing resistivity due to dislocation *** second phases with better matching interfaces to the substrate have no positive effect on the scattering motion of electrons.

关键词： Pure aluminum Rare earths Impurity purification First-principles calculations Strength-conductivity contradiction

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Unsupervised social network embedding via adaptive specific mappings

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Frontiers of Computer science 2024年第3期18卷 61-71页

作者： Youming GE Cong HUANG Yubao LIU Sen ZHANG Weiyang KONG School of Computer science and engineering Sun Yat-Sen UniversityGuangzhou 510275China Guangdong Key Laboratory of Big Data analysis and Processing Guangzhou 510006China

In this paper,we address the problem of unsuperised social network embedding,which aims to embed network nodes,including node attributes,into a latent low dimensional *** recent methods,the fusion mechanism of node attributes and network structure has been proposed for the problem and achieved impressive prediction ***,the non-linear property of node attributes and network structure is not efficiently fused in existing methods,which is potentially helpful in learning a better network *** this end,in this paper,we propose a novel model called ASM(Adaptive Specific Mapping)based on encoder-decoder *** encoder,we use the kernel mapping to capture the non-linear property of both node attributes and network *** particular,we adopt two feature mapping functions,namely an untrainable function for node attributes and a trainable function for network *** the mapping functions,we obtain the low dimensional feature vectors for node attributes and network structure,***,we design an attention layer to combine the learning of both feature vectors and adaptively learn the node *** encoder,we adopt the component of reconstruction for the training process of learning node attributes and network *** conducted a set of experiments on seven real-world social network *** experimental results verify the effectiveness and efficiency of our method in comparison with state-of-the-art baselines.

关键词： network embedding specific kernel mapping attention mechanism

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A game-theoretic approach for federated learning:A trade-off among privacy,accuracy and energy

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Digital Communications and Networks 2024年第2期10卷 389-403页

作者： Lihua Yin Sixin Lin Zhe Sun Ran Li Yuanyuan He Zhiqiang Hao Cyberspace Institute of Advanced Technology Guangzhou UniversityGuangzhou510006China School of Cyber science and engineering Huazhong University of Science and TechnologyWuhan430074China China Industrial Control Systems Cyber Emergency Response team Beijing100040China

Benefiting from the development of Federated Learning(FL)and distributed communication systems,large-scale intelligent applications become *** devices not only provide adequate training data,but also cause privacy leakage and energy *** to optimize the energy consumption in distributed communication systems,while ensuring the privacy of users and model accuracy,has become an urgent *** this paper,we define the FL as a 3-layer architecture including users,agents and *** order to find a balance among model training accuracy,privacy-preserving effect,and energy consumption,we design the training process of FL as game *** use an extensive game tree to analyze the key elements that influence the players’decisions in the single game,and then find the incentive mechanism that meet the social norms through the repeated *** experimental results show that the Nash equilibrium we obtained satisfies the laws of reality,and the proposed incentive mechanism can also promote users to submit high-quality data in *** the multiple rounds of play,the incentive mechanism can help all players find the optimal strategies for energy,privacy,and accuracy of FL in distributed communication systems.

关键词： Federated learning Privacy preservation Energy optimization Game theory Distributed communication systems

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Surface/Interface engineering of Hierarchical MoO_(2)/MoNi_(4)@Ru/RuO_(2)Heterogeneous Nanosheet Arrays for Alkaline Water Electrolysis with Fast Kinetics

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Chinese Journal of Chemistry 2024年第2期42卷 119-128页

作者： Qiong Zhang Ruixue Zhang Yingxiu Zhao Tiantian Sun Jianyang Gao Guang-Rui Xu Zexing Wu Yu Yang Lei Wang Key Laboratory of Eco-chemical engineering Key Laboratory of Optic-electric Sensing and Analytical Chemistry of Life ScienceTaishan Scholar Advantage and Characteristic Discipline Team of Eco Chemical Process and TechnologyCollege of Chemistry and Molecular EngineeringSchool of Materials Science and EngineeringQingdao University of Science and TechnologyQingdaoShandong 266042China College of Environment and Safety engineering Qingdao University of Science and TechnologyQingdaoShandong 266042China

Realizing the hydrogen economy by water electrolysis is an attractive approach for hydrogen production,while the efficient and stable bifunctional catalysts under high current densities are the bottleneck that limits the half-cell reactions of water ***,we propose an approach of hydrothermal and thermal annealing methods for robust MoO_(2)/MoNi_(4)@Ru/RuO_(2) heterogeneous cuboid array electrocatalyst with multiplying surface-active sites by depositing a monolayer amount of *** from abundant MoO_(2)/MoNi_(4)@Ru/RuO_(2)heterointerfaces,MoO_(2)/MoNi_(4)@Ru/RuO_(2) heterogeneous cuboid array electrocatalysts effectively drive the alkaline water splitting with superior hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)*** synthesized MoO_(2)/MoNi_(4)@Ru/RuO_(2) has high HER activity,which realizes the working overpotentials of 48 mV at 50 mA·cm^(-2),further achieving overpotentials of 230 mv for industry-level 1000 mA·cm^(-2) in alkaline water ***,it also showed an enhanced OER activity than commercial RuO_(2) with a small overpotential of 280 mV at 200 mA·cm^(-2) in alkaline *** building an electrolyzer with electrodes of(-)MoO_(2)/MoNi_(4)@Ru/RuO_(2)IIMo02/MoNig@Ru/RuO_(2)(+),a cell voltage of 1.63 V and 1.75 V is just required to support the current density of 200 mA·cm^(-2) and 500 mA-cm^(-2) in alkaline water electrolysis,much lower than that of the electrolyzer of(-)Pt/CIIRuO_(2)(+).This work demonstrates that MoO_(2)/MoNig@Ru/RuO_(2) heterogeneous nanosheet arrays are promising candidates for industrial water electrolysis applications,providing a possibility for the exploration of water electrolysis with a large currentdensity.

关键词： Hierarchical heterostructure Surface engineering Bifunctional catalysts Hydrogen evolution reaction Oxygen evolution reaction Watersplitting Catalytic activity Electrocatalysis Heterogeneous catalysis

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Stable multi-electron reaction stimulated by W doping VS_(4)for enhancing magnesium storage performance

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Journal of Energy Chemistry 2024年第2期89卷 89-98,I0004页

作者： Yuxin Tian Jiankang Chen Guofeng Wang Bing Sun Alan Meng Lei Wang Guicun Li Jianfeng Huang Shiqi Ding Zhenjiang Li College of Materials science and engineering Qingdao University of Science and TechnologyQingdao 266042ShandongChina Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life science MOEShandong Key Laboratory of Biochemical AnalysisCollege of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao 266042ShandongChina School of Material science and engineering International S&T Cooperation Foundation of Shaanxi ProvinceXi’an Key Laboratory of Green Manufacture of Ceramic MaterialsShaanxi University of Science and TechnologyXi’an 710021ShaanxiChina

Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion *** high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of ***,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%*** flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction *** fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction *** discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.

关键词： Multi-electron reaction W doping Stable structure Cathode Rechargeable magnesium batteries

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