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Friction 2024年第2期12卷 291-304页

作者： Qingwen DAI Lei CHEN Jiabao PAN Liping SHI Dameng LIU Wei HUANG Xiaolei WANG College of mechanical and Electrical engineering Nanjing University of Aeronautics&AstronauticsNanjing 210016China State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China School of mechanical engineering Anhui Polytechnic UniversityWuhu 241000China School of mechanical engineering Anhui University of TechnologyMa’anshan 243032China

Robust superhydrophobic surfaces with excellent capacities of repelling water and anti-frosting are of importance for many mechanical *** this work,wear-resistant superhydrophobic surfaces were fabricated by curing a mixture of polyurethane acrylate(PUA)coating and 1H,1H,2H,2H-Perfluorodecyltrichlorosilane(HFTCS)on titanium alloy(TC4)surfaces decorated with micropillars pattern,thus,composite functional surfaces with PUA coating in the valleys around the micropillars pattern of TC4 were *** contact angle on fabricated surfaces could reach 167°.Influences of the geometric parameters of micropillars pattern on the apparent contact angle were investigated,and the corresponding wear-resistant property was *** impact and anti-frosting performances on the prepared surfaces were *** optimized design of surface texture with robust superhydrophobicity,controllable droplet impact,and anti-frosting performances was *** design principle is of promising prospects for fabricating superhydrophobic surfaces in traditional mechanical systems.

关键词： surface texture robust superhydrophobic wear-resistant droplet impact anti-frosting

Self-Adaptive and Electric Field-Driven Protective Layer with Anchored Lithium Deposition Enable Stable Lithium Metal Anode

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Energy & Environmental Materials 2024年第3期7卷 32-40页

作者： Ting Chen Luchao Yue Guoqiang Shu Qing Yang Dong Wang Ruoyang Wang Xianyan Qiao Yan Sun Benhe Zhong Zhenguo Wu Xiaodong Guo department of Chemical engineering Sichuan UniversityChengdu 610065China School of mechanical engineering Chengdu UniversityChengdu 610106China

Lithium metal battery has great development potential because of its lowest electrochemical potential and highest theoretical ***,the uneven deposition of Li^(+)flux in the process of deposition and stripping induces the vigorous growth of lithium dendrites,which results in severely battery performance degradation and serious safety ***,the tetragonal BaTiO3 polarized by high voltage corona was used to build an artificial protective layer with uniform positive polarization direction,which enables uniform Li^(+)*** contrast to traditional strategies of using protective layer,which can guide the uniform deposition of lithium *** ferroelectric protective layer can accurately anchor the Li^(+)and achieve bottom deposition of lithium due to the automatic adjustment of the electric ***,the huge volume changes caused by Li^(+)migration change of the lithium metal anode during charging and discharging is functioned to excite the piezoelectric effect of the protective layer,and achieve seamless dynamic tuning of lithium deposition/*** dynamic effect can accurately anchor and capture Li^(+).Finally,the layer-modified Li anode enables reversible Li plating/stripping over 1500 h at 1 mA cm^(-2)and 50℃in symmetric *** addition,the assembled Li-S full cell exhibits over 300 cycles with N/P≈*** work provides a new perspective on the uniform Li^(+)flux at the Li-anode interface of the artificial protective layer.

关键词： dense plating/stripping process electric field ferroelectric materials lithium metal batteries solid electrolyte interphase

Lattice Boltzmann method formulation for simulation of thermal radiation effects on non-Newtonian Al_(2)O_(3) free convection in entropy determination

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1085-1106页

作者： M.NEMATI M.SEFID A.KARIMIPOUR A.J.CHAMKHA Faculty of mechanical engineering Yazd UniversityYazd ***Iran department of mechanical engineering Najafabad BranchIslamic Azad UniversityNajafabad ***Iran Faculty of engineering Kuwait College of Science and TechnologyDoha 35004Kuwait

The simultaneous investigation on the parameters affecting the flow of electrically conductive fluids such as volumetric radiation,heat absorption,heat generation,and magnetic field(MF)is very vital due to its existence in various sectors of industry and *** present research focuses on mathematical modeling to simulate the cooling of a hot component through power-law(PL)nanofluid convection *** temperature reduction of the hot component inside a two-dimensional(2D)inclined chamber with two different cold wall shapes is *** formulation of the problem is derived with the lattice Boltzmann method(LBM)by code writing via the FORTRAN *** variables such as the radiation parameter(0–1),the Hartmann number(0–75),the heat absorption/generation coefficient(−5–5),the fluid behavioral index(0.8–1.2),the Rayleigh number(103–105),the imposed MF angle(0°–90°),the chamber inclination angle(−90°–90°),and the cavity cold wall shape(smooth and curved)are *** findings indicate that the presence of radiation increases the mean Nusselt number value for the shear-thickening,Newtonian,and shear thinning fluids by about 6.2%,4%,and 2%,*** most cases,the presence of nanoparticles improves the heat transfer(HT)rate,especially in the cases where thermal conduction dominates *** is the lowest cooling performance index and MF effect for the cavity placed at an angle of 90°.The application in the design of electronic coolers and solar collectors is one of the practical cases of this numerical research.

关键词： thermal performance analysis heat absorption/generation power-law(PL)Al_(2)O_(3)nanofluid magnetohydrodynamics natural convection volumetric radiation inclined cavity

Design-space adaptation method for multiobjective and multidisciplinary optimization

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Chinese Journal of Aeronautics 2024年第8期37卷 166-189页

作者： Jongho JUNG Kwanjung YEE Shinkyu JEONG department of Aerospace engineering Seoul National UniversitySeoul 08826Republic of Korea department of mechanical engineering Kyunghee UniversityYoungin 17104Republic of Korea

This paper developed a new method that adaptively adjusts a design space by considering the actual solution distribution of a problem to overcome the conventional design-space adaptation method that assumes the solutions distribution to be a normal distribution because the distributions of solutions are rarely normal distributions for real-world *** developed method was applied to nineteen multiobjective test functions that are widely used to evaluate the characteristics and performance of optimization *** results showed that this method adapted the design space to an appropriate design space where the solution existence probability was *** optimization performance achieved using the developed method was higher than that of the conventional ***,the developed method was applied to the conceptual design of an unmanned spacecraft to confirm its validity in real-world design and multidisciplinaryoptimization *** results showed that the Pareto solutions of the developed method were superior to those of conventional ***,the optimization efficiency with the developed method was improved by more than 1.4 times over that of the conventional *** this regard,the developed method has the potential to be applied to complicated real-world optimization problems to achieve better performance and efficiency.

关键词： Multiobjective optimization Multiobjective genetic algorithm Design-space adaptation Multidisciplinary optimization Hypersonic vehicle

A comprehensive review on the processing-property relationships of laser strengthened magnesium

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Journal of Magnesium and Alloys 2024年第1期12卷 1-34页

作者： Alessandro M.Ralls Aaksheta Agnel Pradeep L.Menezes department of mechanical engineering University of Nevada RenoRenoNV 89557United States

Among the existing series of softer metals,magnesium(Mg)has attracted much attention due to its impressive strength-to-weight ***,due to its ease of deformability,Mg tends to suffer from rapid degradation in a wide variety of abrasive and electrochemical *** method of improving its surface properties is through surface modification *** the existing techniques,laser shock peening(LSP)has been one of the most widely utilized processes due to its surface-hardening-like *** this understanding,a comprehensive review has yet to exist that encapsulates the strengthening mechanism of LSP for Mg and its influence in degradation *** review aims to encapsulate the existing research around the LSP field for ***,an understanding of the surface-strengthening effects in relation to its mechanical,tribological,corrosion,and tribo-corrosion characteristics is ***,the feasibility of LSP for Mg materials in critical industries is also *** this work,a novel understanding of LSP for Mg can be understood,which can provide a future direction for research in this field.

关键词： Laser shock peening Magnesium Surface deformation Tribology Microstructure

Cooperative Target Fencing of Multiple Vehicles for a General Target with Connectivity Preservation and Collision Avoidance

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Journal of Systems Science & Complexity 2024年第1期37卷 136-151页

作者： PAN Zini CHEN Ben M department of mechanical and Automation engineering The Chinese University of Hong KongHong KongChina

In this paper,the authors study the cooperative target-fencing problem for n-dimensional systems and a target with a general *** using the velocity of the vehicles,a position feedback control law is proposed to fence the general target into the convex hull formed by the ***,the dynamics of each vehicle is described by a double-integrator *** potential functions are designed to guarantee connectivity preservation of the communication network and collision avoidance among the *** proposed approach can deal with a target whose trajectory is any twice continuously differentiable function of *** effectiveness of the result is verified by a numerical example.

关键词： Multi-agent systems networked systems target fencing

Cool white light and tunable multicolor emission from Tb^(3+)/Dy^(3+)co-activated glasses under different excitations for WLEDs

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Journal of Rare Earths 2024年第1期42卷 46-56,I0002页

作者： L.Vijayalakshmi K.Naveen Kumar Jong Dae Baek department of Automotive engineering Yeungnam UniversityGyeongsanGyeongbuk38541Republic of Korea department of mechanical engineering Yeungnam UniversityGyeongsan38541Republic of Korea

A set of co-doped(Tb^(3+)/Dy^(3+))lithium zinc borate(LZB)glasses were developed by melt *** structural evaluation was performed for synthesized glassy *** Dy^(3+)and Tb^(3+)individually doped glasses exhibit intense yellow and green luminescence bands at 575 nm(^(4)F_(9/2)→^(6)H_(13/2))and543 nm(^(5)D_(4)→^(7)F_(5)),*** sensitization effect of Dy^(3+)on Tb^(3+)was analyzed by increasing the Tb^(3+)content with respect to the optimum Dy^(3+)content(0.5 mol%)in Dy^(3+)/Tb^(3+).The spectral overlay of Dy^(3+)luminescence and Tb^(3+)absorption profiles,Dy^(3+)/Tb^(3+)PL spectra under different excitations 352,362,376,and 385 nm,shortening decay lifetimes of Dy^(3+)in Dy^(3+)/Tb^(3+)co-activated glasses,energy transfer(ET)parameters,chromaticity coordinates and their corresponding correlated temperatures all help to explain ET from Dy^(3+)to Tb^(3+).At 385 nm of Dy^(3+)excitation,the optimized co-activated(0.5Dy^(3+)+1.0Tb^(3+)):LZB glass displays cool white light *** non-radiative ET from Dy^(3+)to Tb^(3+)is dominated by electric dipole-dipole interaction and its ET efficiency was calculated to be 63%.At the same time,reverse ET from Tb^(3+)to Dy^(3+)was also *** shift in color coordinates from dominant yellow to greenish-yellow,green and white light emission suggests that Dy^(3+)/Tb^(3+)coactivated LZB glasses can be a potential candidate for UV converted multicolor and white light emitting devices.

关键词： Rare earths Photoluminescence Energy transfer Spectral overlap Decay lifetime Multicolor emitting LEDs

Spark Plasma Sintering of Mg-based Alloys:Microstructure,mechanical Properties,Corrosion Behavior,and Tribological Performance

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Journal of Magnesium and Alloys 2024年第2期12卷 405-442页

作者： Alessandro M.Ralls Mohammadreza Daroonparvar Pradeep L.Menezes department of mechanical engineering University of Nevada RenoRenoNV89557United States

Within the past ten years,spark plasma sintering(SPS)has become an increasingly popular process for Mg *** the SPS process,interparticle diffusion of compressed particles is rapidly achieved due to the concept of Joule *** to traditional and additive manufacturing(AM)techniques,SPS gives unique control of the structural and microstructural features of Mg *** doing so,their mechanical,tribological,and corrosion properties can be *** great advancements in this field have been made,these pieces of knowledge are scattered and have not been contextualized into a single *** motivation of this work is to address this scientific gap and to provide a groundwork for understanding the basics of SPS manufacturing for *** do so,the existing body of SPS Mg literature was first surveyed,with a focus on their structural formation and degradation *** was found that successful Mg SPS fabrication highly depended on the processing temperature,particle size,and particle *** addition of metal and ceramic composites also affected their microstructural features due to the Zener pinning *** degradative environments,their performance depends on their structural features and whether they have secondary phased *** industrial applications,SPS'd Mg was found to have great potential in biomedical,hydrogen storage,battery,automotive,and recycling *** prospects to advance the field include using Mg as a doping agent for crystallite size refinement and using bulk metallic Mg-based glass powders for amorphous SPS *** these findings,the interactions of multi-composites on the processing-structure-property relationships of SPS Mg is not well *** total,this work will provide a useful direction in the SPS field and serve as a milestone for future Mg-based SPS manufacturing.

关键词： Spark plasma sintering Magnesium alloys Nanocrystalline Tribology mechanical properties Corrosion

Machine-learned wearable sensors for real-time hand-motion recognition: toward practical applications

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National Science Review 2024年第2期11卷 231-263页

作者： Kyung Rok Pyun Kangkyu Kwon Myung Jin Yoo Kyun Kyu Kim Dohyeon Gong Woon-Hong Yeo Seungyong Han Seung Hwan Ko department of mechanical engineering Seoul National University IEN Center for Human-Centric Interfaces and engineering Institute for Electronics and NanotechnologyGeorgia Institute of Technology School of Electrical and Computer engineering Georgia Institute of Technology department of Chemical engineering Stanford University department of mechanical engineering Ajou University George W.Woodruff School of mechanical engineering Georgia Institute of Technology Institute of Advanced Machinery and Design(SNU-IAMD) Seoul National University

Soft electromechanical sensors have led to a new paradigm of electronic devices for novel motion-based wearable applications in our daily lives. However, the vast amount of random and unidentified signals generated by complex body motions has hindered the precise recognition and practical application of this technology. Recent advancements in artificial-intelligence technology have enabled significant strides in extracting features from massive and intricate data sets, thereby presenting a breakthrough in utilizing wearable sensors for practical applications. Beyond traditional machine-learning techniques for classifying simple gestures, advanced machine-learning algorithms have been developed to handle more complex and nuanced motion-based tasks with restricted training data sets. Machine-learning techniques have improved the ability to perceive, and thus machine-learned wearable soft sensors have enabled accurate and rapid human-gesture recognition, providing real-time feedback to users. This forms a crucial component of future wearable electronics, contributing to a robust human–machine interface. In this review, we provide a comprehensive summary covering materials, structures and machine-learning algorithms for hand-gesture recognition and possible practical applications through machine-learned wearable electromechanical sensors.

关键词： wearable sensor soft electronics artificial intelligence machine learning human–machine interfaces gesture recognition

Internal flow in sessile droplets induced by substrate oscillation:towards enhanced mixing and mass transfer in microfluidic systems

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Microsystems & Nanoengineering 2024年第3期10卷 369-379页

作者： Tianyi Zhang Peng Zhou Terrence Simon Tianhong Cui department of mechanical engineering University of MinnesotaMinneapolisMN 55455USA

The introduction of flows within sessile droplets is highly effective for many lab-on-a-chip chemical and biomedical ***,generating such flows is difficult due to the typically small droplet ***,we present a simple,non-contact strategy to generate internal flows in sessile droplets for enhancing mixing and mass *** flows are driven by actuating a rigid substrate into oscillation with certain amplitude distributions without relying on the resonance of the droplet *** oscillation characteristics and corresponding flow patterns are documented *** indices and mass transfer coefficients of sessile droplets on the substrate surface are measured using optical and electrochemical *** demonstrate complete mixing within the droplets in 1.35 s and increases in mass transfer rates of more than seven times static *** of concept was conducted with experiments of silver nanoparticle synthesis and with heavy metal ion sensing employing the sessile droplet as a microreactor for synthesis and an electrochemical cell for *** degrees of enhancement of synthesis efficiency and detection sensitivity attributed to the internal flows are experimentally documented.

关键词： mixing oscillation synthesis