Miranda Priestly,the remarkable antagonist in Lauren Weisberger’s best-seller The Devil Wears Prada,has been widely considered to be a typical tyrannical female leader since the novel was published.Her forceful image...Miranda Priestly,the remarkable antagonist in Lauren Weisberger’s best-seller The Devil Wears Prada,has been widely considered to be a typical tyrannical female leader since the novel was published.Her forceful image and her impolite language features have attracted researcher’s attention,but the puzzle remains of why Miranda is a fashionable devil of great charm.To figure it out,this paper investigated the characterization of Miranda by exploring the explicit and implicit aspects of the novel’s characterization as well as the multiple faces of Miranda Priestly.It was found that Lauren mainly used the protagonist Andrea’s description,dialogues between Andrea and other characters,Miranda’s remarks and behaviour to create the character,Miranda.She is a multifaceted person and her complexity made her a realistic round character.She has become a representative sample of a bossy female leader owing to her perfectionism,unreasonableness,arrogance and self-centredness.However,Miranda is still a lovable character for the following reasons:First,the things she does are contradictory and ironic.Second,her perfectionism made people work at Runway in a comical way.Lastly,Miranda’s great talent as a fashion magazine editor,her marvellous achievements as well as her perfectionism can compensate for the suffering she has caused.The findings are believed to make a positive contribution to practical knowledge of building a bossy female leader character.展开更多
Micron-sized graphene sheets have been introduced as additives to enhance the lubricating capabilities of water.The tribological characteristics of the lubricants after preparation and storage for 6 months were system...Micron-sized graphene sheets have been introduced as additives to enhance the lubricating capabilities of water.The tribological characteristics of the lubricants after preparation and storage for 6 months were systematically analyzed.Results indicated that the friction coefficient and wear volume of the tribo-pair were reduced through the incorporation of a certain concentration of graphene sheets,and also have long-term storage stability.Notably,under the experimental conditions,a 0.2%mass concentration of graphene in the aqueous lubricant exhibited exceptional tribological performance and long-term storage stability,achieving an 80%reduction in friction coefficient and a 78%decrease in wear volume with a 14000-cycle friction test.Wear morphology analysis indicated that after adding graphene sheets to the aqueous solution,micro-plastic deformation occurs on the worn surface of the steel plate.The wear profile of the GCr15 counter ball changes from a circular profile to a rectangular-like profile.The main reason is that the graphene sheets in the aqueous solution can enter the contact interface during the friction process,hindering direct contact between the friction pair.The study prov-ides a simple method to improve the tribological properties of aqueous solutions stably for engineering applica-tions.展开更多
Accurate tool wear prediction is crucial for manufacturing efficiency,yet effectively using multi-domain sensor features is difficult due to redundant noise.There is a critical need to strategically leverage highly pr...Accurate tool wear prediction is crucial for manufacturing efficiency,yet effectively using multi-domain sensor features is difficult due to redundant noise.There is a critical need to strategically leverage highly predictive strong features and potentially informative weak features.To address this issue,we propose CdualTAL,an improved Transformer-based encoder-attention-decoder algorithm.Its name represents the model’s key components:a correlation-adaptive feature selection algorithm module,a dual-channel Transformer encoder,an attention mechanism,and a long short-term memory(LSTM)decoder.CdualTAL employs a dual-channel encoder to independently process the full set of multi-domain features,along with a subset of strong features selected using a designed correlation-adaptive feature selection algorithm.A custom cross-attention mechanism is then used to fuse these representations,sharpening focus on strong features while judiciously integrating information from weak ones.Finally,a hierarchical LSTM decoder captures deep temporal dependencies.Validated on tool wear datasets,CdualTAL outperforms 11 state-of-the-art methods,achieving superior prediction stability and accuracy with an average R2 of 0.983 and a root mean square error(RMSE)of 4.373.展开更多
The corrosion wear behavior of the selective laser melting(SLM)and forged TC4 alloys in 3.5 wt.%NaCl solution is studied.Results indicate that the current densities of the two TC4 alloys increase with the increase in ...The corrosion wear behavior of the selective laser melting(SLM)and forged TC4 alloys in 3.5 wt.%NaCl solution is studied.Results indicate that the current densities of the two TC4 alloys increase with the increase in applied potential,meaning that the corrosion resistance of the alloys decreases.And the main product of the passive film is TiO_(2).What’s more,corrosion wear behavior is more severe due to the presence of corrosion,resulting in greater mass losses and deeper wear scars.To explore the interaction between corrosion and wear for the two TC4 alloys,the change of the mass loss proportions for wear caused by corrosion and corrosion caused by wear with potential is analyzed.The mass loss of wear caused by corrosion cannot be ignored,and it affects SLM TC4 alloy with the unique acicularα′-phase significantly.展开更多
To solve the problem of abnormal abrasion of Cu-Based Friction Materials(CBFMs),Bionic Non-Smooth Surface(BNS)on friction surface of CBFMs was constructed based on bionic principles,and the optimal bionic prototype wa...To solve the problem of abnormal abrasion of Cu-Based Friction Materials(CBFMs),Bionic Non-Smooth Surface(BNS)on friction surface of CBFMs was constructed based on bionic principles,and the optimal bionic prototype was selected by Finite Element Method(FEM).In addition,the bionic parameters were optimized by Response Surface Method(RSM).Samples holding BNS were prepared by Laser Processing,tribological properties were tested by a Friction and Wear Tester and worn surface morphology was characterized by a Scanning Electron Microscope(SEM).The results showed that BNS on friction surface could regulate the stress distribution and alleviate the peak stress.Among all samples,the coupled texture of pit-hexagonal got the minimum peak stress.During braking,bionic texture could also collect wear debris or change the motion forms from sliding to rotation,which can reduce abnormal abrasion.The wear rate was reduced by 19.31%.The results in this paper can provide a new idea for enhancing the tribological properties of CBFMs,and can also lay the foundation for further research of bionic tribology.展开更多
Development of lightweight and strong structural material using fast-growing poplar wood is promising for green and sustainable engineering.Herein,the overall performances of fast-growing natural poplar wood(NPW)are s...Development of lightweight and strong structural material using fast-growing poplar wood is promising for green and sustainable engineering.Herein,the overall performances of fast-growing natural poplar wood(NPW)are significantly enhanced via delignification,in situ growth of SiO_(2)followed by densification.The SiO_(2)/compresseddelignified-wood(SiO_(2)/CDW)nanocomposite obtained exhibits outstanding mechanical properties including a bending strength of 395.6 MPa,a tensile strength of 253.4 MPa,and a toughness of 7.1 MJ/m^(3),which is improved by 1548%,240%and 590%,respectively compared with NPW.In addition,the ignition time and burning time of SiO_(2)/CDW nanocomposite are prolonged by 700%and 112%compared to those of NPW.Moreover,the specific wear rate of SiO_(2)/CDW is 18×10^(-6)mm^(3)/Nm,which is 72.6%lower than that of NPW.Moreover,the spring-back ratios of SiO_(2)/CDW in 95%and in water are 45.2%and 66.7%,which are lower than those of CDW(64.6%and 92.4%).The SiO_(2)/CDW nanocomposite with enhanced mechanical,flame/water retardant and wear performances are promising to meet the needs of modern engineering as green and sustainable materials.展开更多
Nickel-based single-crystal superalloy DD98M is widely used in high-temperature components such as aero-engines and gas turbines.Since it has only one crystal grain,the theory of slip deformation along the grain bound...Nickel-based single-crystal superalloy DD98M is widely used in high-temperature components such as aero-engines and gas turbines.Since it has only one crystal grain,the theory of slip deformation along the grain boundary of polycrystalline material is not suitable for the machining of a single crystal part.Therefore,micro-drilling of nickel-based single crystal superalloy still faces problems such as unclear cutting formation me-chanism and unclear surface/subsurface damage mechanism.In this paper,the formation mechanism and morphological characteristics of chips and burrs were studied by a single-factor experiment,and the plastic deformation rule and damage mechanism were investigated,combined with the changes of subsurface structure and grain type.Finally,the influence of the law and reason of tool wear condition on the hole wall and the drilled subsurface is analyzed.The experimental results indicate that drill chips mainly exhibit three morphologies.Their free surfaces feature a serrated appearance,while the contact surfaces are smooth.The entrance burrs are mainly flanging burrs.With the increase of spindle speed,the burr height decreases from 49.38 to 9.39μm.As the feed speed increases,the burr height increases from 6.50 to 63.87μm.The drilled subsurface can be divided into a white layer region,a plastic deformation region,and the matrix according to the microstructural change.As the depth from the machined surface increases,the degree of plastic deformation of the material decreases,the grain size gradually reduces,and the dislocation density decreases.Stacking fault and twinning mostly occur in the high-plastic deformation region,and recrystallization occurs on the machined surface.As the drilling length increases,the degree of tool wear increases,and the adhesion and ablation area on the hole wall surface increase.Moreover,the thickness of the white layer increases from 0 to 8.75μm,and the thickness of the plastic deformation layer increases from 1.28 to 11.31μm.The study has significant theoretical and practical implications for the efficient and low-damage machining of micro-holes in the nickel-based single crystal superalloy.展开更多
The application of oil debris monitoring technology to lubricating oil has gained substantial prominence as a diagnostic tool for identifying machinery and equipment wear-related issues.Among the various methods avail...The application of oil debris monitoring technology to lubricating oil has gained substantial prominence as a diagnostic tool for identifying machinery and equipment wear-related issues.Among the various methods available for wear fault monitoring,the detection of changing electromagnetic fields using triple-coil inductive sensors are widely used because of its inherent simplicity of design and operational convenience in facilitating full-flow detection.However,the accuracy of this method is limited by several factors.In this study,an intricate simulation model of the internal magnetic field in a triple-coil inductive sensor was developed.Subsequently,the effects of the excitation signal frequency and wear particle composition on the magnetic flux density were analyzed.The simulation results show an optimal excitation frequency range of approximately 2100 kHz for ferromagnetic particle detection,whereas nonferromagnetic metal particles require higher excitation fre-quencies.With an increase in the distance between adjacent wear particles,the magnetic coupling effect de-creased rapidly.Moreover,the magnetic flux density changed from its maximum value to a minimum value as the rotation angle of the particles increased from 0°to 90°.A special experimental platform was constructed to verify the simulation results,and the experimental results were consistent with the simulation results.展开更多
The effect of heat treatment and ionic nitriding on the microstructure and surface performance of a newly developed precipitation-hardenable martensitic steel designed for laser powder bed fusion(L-PBF)was investigate...The effect of heat treatment and ionic nitriding on the microstructure and surface performance of a newly developed precipitation-hardenable martensitic steel designed for laser powder bed fusion(L-PBF)was investigated.The alloy,formulated without cobalt or molybdenum and with reduced nickel content(~7 wt.%),exhibits a refined cellular microstructure in the as-built state,with localised elemental segregation and nanoscale precipitation.A full factorial experimental design was applied to assess the individual and interactive effects of austenitisation,ageing,and nitriding on hardness,adhesive wear resistance,and corrosion behaviour.Ageing promoted Ni3Ti-type precipitation and increased hardness by 82%relative to the as-built state.Ionic nitriding produced a~30µm hardened layer,enhanced surface hardness(HV10,test force of approximately 98.1 N),and reduced wear by up to 97%.However,this treatment significantly impaired corrosion resistance,lowering polarisation resistance by 89%and increasing the corrosion current density by a factor of 4.6.The absence of protective titanium oxides and the presence of nitriding-induced microcracks were identified as the main contributors to this degradation.These results suggest that ageing alone offers the most balanced post-processing strategy when wear and corrosion coexist,whereas nitriding should be restricted to applications dominated by surface wear.展开更多
The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of...The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of high‐content graphene reinforcements.This compromise becomes particularly severe in composites with high‐content graphene reinforcements,whose agglomeration leads to embrittlement and lubrication failure.Here,a flake powder-metallurgy strategy is developed to construct a self‐assembled lamellar structure in graphene/CoCrNi MPEA composites(Gr/MPEA_(AL)).This approach enables the uniform dispersion of a high graphene content(3.0 wt%),which is unattainable by conventional methods.The resulting composite exhibits a rare dual enhancement in performance:an order‐of‐magnitude improvement in wear resistance coupled with a low coefficient of friction.Intriguingly,the tribological behavior shows significant anisotropy,with optimal performance observed when sliding perpendicular to the lamellae.Through a multi‐scale methodology combining molecular dynamics simulations,finite element analysis,and systematic experiments,it is revealed that this exceptional performance stems from the synergy of high‐density deformation nanotwins,efficient strain delocalization,and abundant graphene‐derived lubricating sites.This work establishes a general paradigm for designing composite architectures that reconcile traditionally incompatible properties,offering broad implications for developing next‐generation structural materials with integrated mechanical robustness and surface functionality for safety‐critical applications.展开更多
This study investigated enhancing the wear resistance of Ti6Al4V alloys for medical applications by incorporating Ti C nanoreinforcements using advanced spark plasma sintering(SPS). The addition of up to 2.5wt% Ti C s...This study investigated enhancing the wear resistance of Ti6Al4V alloys for medical applications by incorporating Ti C nanoreinforcements using advanced spark plasma sintering(SPS). The addition of up to 2.5wt% Ti C significantly improved the mechanical properties, including a notable 18.2% increase in hardness(HV 332). Fretting wear tests against 316L stainless steel(SS316L) balls demonstrated a 20wt%–22wt% reduction in wear volume in the Ti6Al4V/Ti C composites compared with the monolithic alloy. Microstructural analysis revealed that Ti C reinforcement controlled the grain orientation and reduced the β-phase content, which contributed to enhanced mechanical properties. The monolithic alloy exhibited a Widmanstätten lamellar microstructure, while increasing the Ti C content modified the wear mechanisms from ploughing and adhesion(0–0.5wt%) to pitting and abrasion(1wt%–2.5wt%). At higher reinforcement levels, the formation of a robust oxide layer through tribo-oxide treatment effectively reduced the wear volume by minimizing the abrasive effects and plastic deformation. This study highlights the potential of SPS-mediated Ti C reinforcement as a transformative approach for improving the performance of Ti6Al4V alloys, paving the way for advanced medical applications.展开更多
SiCp-reinforced 6092Al composites with volume fractions of 25%and 60%were prepared using a powder metallurgy method.Their friction and wear characteristics were analyzed using a reciprocating friction and wear testing...SiCp-reinforced 6092Al composites with volume fractions of 25%and 60%were prepared using a powder metallurgy method.Their friction and wear characteristics were analyzed using a reciprocating friction and wear testing machine under loads of 20 to 50 N against YG6 cemented carbide.The experimental results show that the friction coefficients of all samples increase with increasing load.The 25vol%composite exhibits the lowest friction coefficient(0.1669-0.2716),while the 60vol%composite exhibits the highest(0.3237-0.3990),with the 6092 aluminum alloy falling between the two.The wear volume and specific wear rate also increase with load,but the composites with a higher Si C content demonstrate smaller increments,with the 60vol%composite exhibiting superior wear resistance.Under a 30 N load,the wear scars of the 60vol%composite show a significant increase in the contents of elements such as C,Co,W,and O,indicating more severe wear of the counterpart material.Scanning electron microscopy(SEM)reveals wear mechanisms including adhesive wear,two-body sliding and three-body rolling wear of particles,and delamination.展开更多
Internal leakage caused by wear in hydraulic spool valves represents a critical failure mode that threatens the performance of aircraft hydraulic systems and compromises flight safety.Due to complex operational loads ...Internal leakage caused by wear in hydraulic spool valves represents a critical failure mode that threatens the performance of aircraft hydraulic systems and compromises flight safety.Due to complex operational loads and time-varying material properties,the relationship between wear state and Remaining Useful Life(RUL)is nonlinear.Consequently,accurately modeling this wear remains a significant challenge,as existing research often neglects the coupled effects of material properties,stress conditions,and dynamic lubrication parameters.To address this issue,this study proposes a novel framework integrating physical mechanisms with stochastic processes to enhance wear degradation modelling and RUL prediction.First,a Physics-of-Failure(PoF)model is developed based on Archard's wear theory,which characterizes tribological behavior at the contact interface and accounts for the effects of lubrication and load conditions.Next,a Gamma process is introduced to model the degradation trajectory,with physical parameters guiding the specification of the time-scale function.A Bayesian expectation–maximization algorithm is employed to estimate and update the model parameters.Finally,a numerical simulation and case study on spool valves are conducted to demonstrate the effectiveness of the proposed model.The cross-validation results confirmed that the introduction of random effects effectively reduces the impact of uncertainty on physics-informed modeling.This study offers a systematic solution to RUL prediction for hydraulic systems.展开更多
Laser remelting(LR)was used as an auxiliary post-treatment process for the Ti6Al4V titanium alloys fabricated by laser powder bed fusion(LPBF).Optical microscope(OM),scanning electron microscope(SEM)and electron back ...Laser remelting(LR)was used as an auxiliary post-treatment process for the Ti6Al4V titanium alloys fabricated by laser powder bed fusion(LPBF).Optical microscope(OM),scanning electron microscope(SEM)and electron back scattering diffraction(EBSD)observations showed that the grains in melted zone(MZ)transformed into equiaxial grains with an average size of 1.31μm,and the grains in heat affected zone(HAZ)were refined.Moreover,the texture intensity dropped significantly from 13.86 to 6.35 in MZ and 10.79 in HAZ.The temperature gradient(G)to solidification rate(R)ratio decreased when the laser scanning speed slowed down to a certain extent in the LR process,which effectively improved the highly preferred orientation and filled the hole defects in the surface of LPBF-Ti6Al4V.Furthermore,the hardness,wear resistance and corrosion resistance of the surface of the LPBF samples were improved by LR treatment.展开更多
Diffusion shaped film cooling holes with compound-angle diffuser structures exhibit superior cooling performance,which have gradually been applied in turbine blades of the advanced aeroengines.In our previous research...Diffusion shaped film cooling holes with compound-angle diffuser structures exhibit superior cooling performance,which have gradually been applied in turbine blades of the advanced aeroengines.In our previous research,the method of Servo Scanning three-dimensional Electrical Discharge Machining(SS-3D EDM)has been proven effective for high-precision machining of complex 3D cavities,offering notable advantages such as low tool cost,automatic compensation of electrode wear,and high machining flexibility.However,using tubular electrodes in SS-3D EDM,challenges persist under the conditions of the large layer depth.The lateral discharge phenomenon of tubular electrodes causes significant deformation at the electrode tip,increases the risk of lateral collisions,and complicates the accurate calculation of electrode wear length.To address these limitations,this research proposes a Trajectory Servo Scanning three-dimensional Electrical Discharge Machining(TSS-3D EDM)process.Axial servo motion of tubular electrode is used to maintain the discharge gap of electrode bottom,and an innovative trajectory servo motion along the tangential orientation is introduced to stabilize the lateral discharge gap,enabling automatic compensation for tool wear at the rotating electrode tip.The effect of servo control parameters on machining depth accuracy is analyzed.Furthermore,a method for electrode wear length calculation is proposed based on the voltage signals of discharge gaps.An estimation method for the electrode wear coefficient is presented.Machining experiments on superalloys validate the effectiveness and capabilities of the TSS-3D EDM method by fabricating fan-shaped and conical diffusion shaped film cooling holes.The results show that the calculation error of tubular electrode wear length<5%,the dimensional error of hole profile dimensions as 4%–6%,the repeatability error<±4μm,and the material removal rate up to 0.664 mm^(3)/min using tubular electrodes with an outer diameter of 0.4 mm.展开更多
本文探讨Art to Wear即“可以穿的艺术”,其中大部分作品为服装,少量作品是帽子和首饰。通过分析Art to Wear代表艺术家,解读Art to Wear艺术作品,从而探讨美国20世纪60年代到80年代女性艺术家群体如何以艺术为媒介对自身经历进行叙述...本文探讨Art to Wear即“可以穿的艺术”,其中大部分作品为服装,少量作品是帽子和首饰。通过分析Art to Wear代表艺术家,解读Art to Wear艺术作品,从而探讨美国20世纪60年代到80年代女性艺术家群体如何以艺术为媒介对自身经历进行叙述性表现。60年代末70年代初处于美国女性主义的第二次浪潮,众多美国名校的年轻白人女大学生,不断为女性的参政、就业、医疗、最低工资等争取更多的权利,而到了80年代遭到美国保守主义的强烈打击,追求自由平等的女性主义运动跌入低谷。第二次女性主义运动的跌宕正是Art to Wear艺术运动的发展时期,艺术学院在读青年女生们发起Art to Wear艺术运动,她们在保守主义与激进主义的影响下寻求精神、生活的平衡,极力反叛女性束身塑形来博得男性视觉愉悦、通过同性的嫉妒来肯定自身价值。她们对家庭、事业、社会地位开始深思,通过作品叙述对社会性别与身份认定的迷茫,表达保守与激进思想的内心纠结。展开更多
In-situ formed high Mn steel coating reinforced by carbides was formed by laser surface alloying(LSA).Laser alloyed layers on 1Cr18Ni9Ti steel with Mn+W_(2)C(specimen A),Mn+NiWC(specimen B)and Mn+SiC(specimen C)powder...In-situ formed high Mn steel coating reinforced by carbides was formed by laser surface alloying(LSA).Laser alloyed layers on 1Cr18Ni9Ti steel with Mn+W_(2)C(specimen A),Mn+NiWC(specimen B)and Mn+SiC(specimen C)powders were fabricated to improve the wear and corrosion behavior of 1Cr18Ni9Ti steel blades in high speed mixers.Microstructure evolution,phases,element distribution,microhardness,wear and corrosion behavior of the laser alloyed layers were investigated.Results indicated that high Mn steel matrix composites with undissolved W_(2)C,WC and other in-situ formed carbides were formed by LSA with Mn+W_(2)C and Mn+NiWC while SiC totally dissolved into the high Mn matrix when adding Mn+SiC.Ni as the binding phase in Ni-WC powder decreased the crack sensitivity of the alloyed layer as compared with the addition of W_(2)C powder.An improvement in average microhardness was achieved in the matrix in specimen A,B and C,with the value of 615,602 and 277 HV_(0.5),while that of the substrate was 212 HV_(0.5).The increase of microhardness,wear and corrosion resistance is highly corelated to microstructure,formed phases,type and content of carbides,micro-hardness and toughness of the alloyed layers.展开更多
Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,a...Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.展开更多
文摘Miranda Priestly,the remarkable antagonist in Lauren Weisberger’s best-seller The Devil Wears Prada,has been widely considered to be a typical tyrannical female leader since the novel was published.Her forceful image and her impolite language features have attracted researcher’s attention,but the puzzle remains of why Miranda is a fashionable devil of great charm.To figure it out,this paper investigated the characterization of Miranda by exploring the explicit and implicit aspects of the novel’s characterization as well as the multiple faces of Miranda Priestly.It was found that Lauren mainly used the protagonist Andrea’s description,dialogues between Andrea and other characters,Miranda’s remarks and behaviour to create the character,Miranda.She is a multifaceted person and her complexity made her a realistic round character.She has become a representative sample of a bossy female leader owing to her perfectionism,unreasonableness,arrogance and self-centredness.However,Miranda is still a lovable character for the following reasons:First,the things she does are contradictory and ironic.Second,her perfectionism made people work at Runway in a comical way.Lastly,Miranda’s great talent as a fashion magazine editor,her marvellous achievements as well as her perfectionism can compensate for the suffering she has caused.The findings are believed to make a positive contribution to practical knowledge of building a bossy female leader character.
基金Supported by the National Natural Science Foundation of China(Grant Nos.52305186,52275177)the Research Start-up Funding of Fuzhou University(Grant Nos.XRC-23015,XRC-23064).
文摘Micron-sized graphene sheets have been introduced as additives to enhance the lubricating capabilities of water.The tribological characteristics of the lubricants after preparation and storage for 6 months were systematically analyzed.Results indicated that the friction coefficient and wear volume of the tribo-pair were reduced through the incorporation of a certain concentration of graphene sheets,and also have long-term storage stability.Notably,under the experimental conditions,a 0.2%mass concentration of graphene in the aqueous lubricant exhibited exceptional tribological performance and long-term storage stability,achieving an 80%reduction in friction coefficient and a 78%decrease in wear volume with a 14000-cycle friction test.Wear morphology analysis indicated that after adding graphene sheets to the aqueous solution,micro-plastic deformation occurs on the worn surface of the steel plate.The wear profile of the GCr15 counter ball changes from a circular profile to a rectangular-like profile.The main reason is that the graphene sheets in the aqueous solution can enter the contact interface during the friction process,hindering direct contact between the friction pair.The study prov-ides a simple method to improve the tribological properties of aqueous solutions stably for engineering applica-tions.
基金supported by the Shandong Provincial Key Research and Development Program(No.2024CXPT011)the National Key Research and Development Program of China(No.2024YFB3312302).
文摘Accurate tool wear prediction is crucial for manufacturing efficiency,yet effectively using multi-domain sensor features is difficult due to redundant noise.There is a critical need to strategically leverage highly predictive strong features and potentially informative weak features.To address this issue,we propose CdualTAL,an improved Transformer-based encoder-attention-decoder algorithm.Its name represents the model’s key components:a correlation-adaptive feature selection algorithm module,a dual-channel Transformer encoder,an attention mechanism,and a long short-term memory(LSTM)decoder.CdualTAL employs a dual-channel encoder to independently process the full set of multi-domain features,along with a subset of strong features selected using a designed correlation-adaptive feature selection algorithm.A custom cross-attention mechanism is then used to fuse these representations,sharpening focus on strong features while judiciously integrating information from weak ones.Finally,a hierarchical LSTM decoder captures deep temporal dependencies.Validated on tool wear datasets,CdualTAL outperforms 11 state-of-the-art methods,achieving superior prediction stability and accuracy with an average R2 of 0.983 and a root mean square error(RMSE)of 4.373.
基金supported by the National Natural Science Foundation of China(No.52001142)Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001).
文摘The corrosion wear behavior of the selective laser melting(SLM)and forged TC4 alloys in 3.5 wt.%NaCl solution is studied.Results indicate that the current densities of the two TC4 alloys increase with the increase in applied potential,meaning that the corrosion resistance of the alloys decreases.And the main product of the passive film is TiO_(2).What’s more,corrosion wear behavior is more severe due to the presence of corrosion,resulting in greater mass losses and deeper wear scars.To explore the interaction between corrosion and wear for the two TC4 alloys,the change of the mass loss proportions for wear caused by corrosion and corrosion caused by wear with potential is analyzed.The mass loss of wear caused by corrosion cannot be ignored,and it affects SLM TC4 alloy with the unique acicularα′-phase significantly.
基金Wuxi University Research Start-up Fund for Introduced Talents(Grant No:2024r031)Technology Development Contract(Contract Registration Number:2024320205000963)+1 种基金National Natural Science Foundation of China(Grant No.52275288)Ningbo Key Research and Development Plan(Grant No.2023Z022).
文摘To solve the problem of abnormal abrasion of Cu-Based Friction Materials(CBFMs),Bionic Non-Smooth Surface(BNS)on friction surface of CBFMs was constructed based on bionic principles,and the optimal bionic prototype was selected by Finite Element Method(FEM).In addition,the bionic parameters were optimized by Response Surface Method(RSM).Samples holding BNS were prepared by Laser Processing,tribological properties were tested by a Friction and Wear Tester and worn surface morphology was characterized by a Scanning Electron Microscope(SEM).The results showed that BNS on friction surface could regulate the stress distribution and alleviate the peak stress.Among all samples,the coupled texture of pit-hexagonal got the minimum peak stress.During braking,bionic texture could also collect wear debris or change the motion forms from sliding to rotation,which can reduce abnormal abrasion.The wear rate was reduced by 19.31%.The results in this paper can provide a new idea for enhancing the tribological properties of CBFMs,and can also lay the foundation for further research of bionic tribology.
基金the financial support from the National Natural Science Foundation of China(No.52303082)Natural Science Foundation of Hubei Province(No.2023AFB375)Fundamental Research Funds for Central Universities of China(No.2022CDJQY-004)。
文摘Development of lightweight and strong structural material using fast-growing poplar wood is promising for green and sustainable engineering.Herein,the overall performances of fast-growing natural poplar wood(NPW)are significantly enhanced via delignification,in situ growth of SiO_(2)followed by densification.The SiO_(2)/compresseddelignified-wood(SiO_(2)/CDW)nanocomposite obtained exhibits outstanding mechanical properties including a bending strength of 395.6 MPa,a tensile strength of 253.4 MPa,and a toughness of 7.1 MJ/m^(3),which is improved by 1548%,240%and 590%,respectively compared with NPW.In addition,the ignition time and burning time of SiO_(2)/CDW nanocomposite are prolonged by 700%and 112%compared to those of NPW.Moreover,the specific wear rate of SiO_(2)/CDW is 18×10^(-6)mm^(3)/Nm,which is 72.6%lower than that of NPW.Moreover,the spring-back ratios of SiO_(2)/CDW in 95%and in water are 45.2%and 66.7%,which are lower than those of CDW(64.6%and 92.4%).The SiO_(2)/CDW nanocomposite with enhanced mechanical,flame/water retardant and wear performances are promising to meet the needs of modern engineering as green and sustainable materials.
基金Supported by National Natural Science Foundation of China(Grant Nos.52475433,52305453)Hebei Provincial Natural Science Foundation(Grant No.E2022501004)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2023GFYD002)Shijiazhuang Municipal Science and Technology Plan Project(Grant No.241790747A).
文摘Nickel-based single-crystal superalloy DD98M is widely used in high-temperature components such as aero-engines and gas turbines.Since it has only one crystal grain,the theory of slip deformation along the grain boundary of polycrystalline material is not suitable for the machining of a single crystal part.Therefore,micro-drilling of nickel-based single crystal superalloy still faces problems such as unclear cutting formation me-chanism and unclear surface/subsurface damage mechanism.In this paper,the formation mechanism and morphological characteristics of chips and burrs were studied by a single-factor experiment,and the plastic deformation rule and damage mechanism were investigated,combined with the changes of subsurface structure and grain type.Finally,the influence of the law and reason of tool wear condition on the hole wall and the drilled subsurface is analyzed.The experimental results indicate that drill chips mainly exhibit three morphologies.Their free surfaces feature a serrated appearance,while the contact surfaces are smooth.The entrance burrs are mainly flanging burrs.With the increase of spindle speed,the burr height decreases from 49.38 to 9.39μm.As the feed speed increases,the burr height increases from 6.50 to 63.87μm.The drilled subsurface can be divided into a white layer region,a plastic deformation region,and the matrix according to the microstructural change.As the depth from the machined surface increases,the degree of plastic deformation of the material decreases,the grain size gradually reduces,and the dislocation density decreases.Stacking fault and twinning mostly occur in the high-plastic deformation region,and recrystallization occurs on the machined surface.As the drilling length increases,the degree of tool wear increases,and the adhesion and ablation area on the hole wall surface increase.Moreover,the thickness of the white layer increases from 0 to 8.75μm,and the thickness of the plastic deformation layer increases from 1.28 to 11.31μm.The study has significant theoretical and practical implications for the efficient and low-damage machining of micro-holes in the nickel-based single crystal superalloy.
基金Supported by National Natural Science Foundation of China(Grant No.51975539)Aeronautical Science Foundation of China(Grant No.2018ZD55008)+5 种基金Program of the Innovation Research Team of Sci-tech of Hennan Province(Grant No.25IRTSTHN020)Scientific Research Team Plan of Zhengzhou University of Aeronautics(Grant No.23ZHTD01004)Aeronautical Science Foundation of China(Grant No.2018ZD55008)Key Project of the Education Department of Henan Province of China(Grant No.25A590006)Key Science and Technique R&D Program of Henan Province of China(Grant Nos.252102220085,252102240134)The Talent Support Program of Henan Province(Grant No.254000510003).
文摘The application of oil debris monitoring technology to lubricating oil has gained substantial prominence as a diagnostic tool for identifying machinery and equipment wear-related issues.Among the various methods available for wear fault monitoring,the detection of changing electromagnetic fields using triple-coil inductive sensors are widely used because of its inherent simplicity of design and operational convenience in facilitating full-flow detection.However,the accuracy of this method is limited by several factors.In this study,an intricate simulation model of the internal magnetic field in a triple-coil inductive sensor was developed.Subsequently,the effects of the excitation signal frequency and wear particle composition on the magnetic flux density were analyzed.The simulation results show an optimal excitation frequency range of approximately 2100 kHz for ferromagnetic particle detection,whereas nonferromagnetic metal particles require higher excitation fre-quencies.With an increase in the distance between adjacent wear particles,the magnetic coupling effect de-creased rapidly.Moreover,the magnetic flux density changed from its maximum value to a minimum value as the rotation angle of the particles increased from 0°to 90°.A special experimental platform was constructed to verify the simulation results,and the experimental results were consistent with the simulation results.
文摘The effect of heat treatment and ionic nitriding on the microstructure and surface performance of a newly developed precipitation-hardenable martensitic steel designed for laser powder bed fusion(L-PBF)was investigated.The alloy,formulated without cobalt or molybdenum and with reduced nickel content(~7 wt.%),exhibits a refined cellular microstructure in the as-built state,with localised elemental segregation and nanoscale precipitation.A full factorial experimental design was applied to assess the individual and interactive effects of austenitisation,ageing,and nitriding on hardness,adhesive wear resistance,and corrosion behaviour.Ageing promoted Ni3Ti-type precipitation and increased hardness by 82%relative to the as-built state.Ionic nitriding produced a~30µm hardened layer,enhanced surface hardness(HV10,test force of approximately 98.1 N),and reduced wear by up to 97%.However,this treatment significantly impaired corrosion resistance,lowering polarisation resistance by 89%and increasing the corrosion current density by a factor of 4.6.The absence of protective titanium oxides and the presence of nitriding-induced microcracks were identified as the main contributors to this degradation.These results suggest that ageing alone offers the most balanced post-processing strategy when wear and corrosion coexist,whereas nitriding should be restricted to applications dominated by surface wear.
基金supported by Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012378)Natural Science Foundation of China(Nos.52471093,52274367)+3 种基金fund of the State Key Laboratory of Solidification Processing in NPU(No.2025‐QZ‐03)the Practice and Innovation Funds for Graduate Students of Northwestern Polytechnical University(No.PF2025041)Fundamental Research Projects of Science&Technology Innovation and development Plan in Yantai City(No.2024JCYJ099)project(No.ZR2024QE213)supported by Shandong Provincial Natural Science Foundation.
文摘The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of high‐content graphene reinforcements.This compromise becomes particularly severe in composites with high‐content graphene reinforcements,whose agglomeration leads to embrittlement and lubrication failure.Here,a flake powder-metallurgy strategy is developed to construct a self‐assembled lamellar structure in graphene/CoCrNi MPEA composites(Gr/MPEA_(AL)).This approach enables the uniform dispersion of a high graphene content(3.0 wt%),which is unattainable by conventional methods.The resulting composite exhibits a rare dual enhancement in performance:an order‐of‐magnitude improvement in wear resistance coupled with a low coefficient of friction.Intriguingly,the tribological behavior shows significant anisotropy,with optimal performance observed when sliding perpendicular to the lamellae.Through a multi‐scale methodology combining molecular dynamics simulations,finite element analysis,and systematic experiments,it is revealed that this exceptional performance stems from the synergy of high‐density deformation nanotwins,efficient strain delocalization,and abundant graphene‐derived lubricating sites.This work establishes a general paradigm for designing composite architectures that reconcile traditionally incompatible properties,offering broad implications for developing next‐generation structural materials with integrated mechanical robustness and surface functionality for safety‐critical applications.
文摘This study investigated enhancing the wear resistance of Ti6Al4V alloys for medical applications by incorporating Ti C nanoreinforcements using advanced spark plasma sintering(SPS). The addition of up to 2.5wt% Ti C significantly improved the mechanical properties, including a notable 18.2% increase in hardness(HV 332). Fretting wear tests against 316L stainless steel(SS316L) balls demonstrated a 20wt%–22wt% reduction in wear volume in the Ti6Al4V/Ti C composites compared with the monolithic alloy. Microstructural analysis revealed that Ti C reinforcement controlled the grain orientation and reduced the β-phase content, which contributed to enhanced mechanical properties. The monolithic alloy exhibited a Widmanstätten lamellar microstructure, while increasing the Ti C content modified the wear mechanisms from ploughing and adhesion(0–0.5wt%) to pitting and abrasion(1wt%–2.5wt%). At higher reinforcement levels, the formation of a robust oxide layer through tribo-oxide treatment effectively reduced the wear volume by minimizing the abrasive effects and plastic deformation. This study highlights the potential of SPS-mediated Ti C reinforcement as a transformative approach for improving the performance of Ti6Al4V alloys, paving the way for advanced medical applications.
基金Funded by the Provincial Talent Project of Gansu Province(No.2025QNGR18)the Natural Science Foundation of Gansu Province(No.23JRRA1647)+2 种基金the"Qizhi"Talent Cultivation Project of Lanzhou Institute of Technology(No.2025QZ-02)the Education Science and Technology Innovation Project of Gansu Province(No.2025A-229)the Lanzhou Science and Technology Development Guidance Plan Project(No.2024-9-307)。
文摘SiCp-reinforced 6092Al composites with volume fractions of 25%and 60%were prepared using a powder metallurgy method.Their friction and wear characteristics were analyzed using a reciprocating friction and wear testing machine under loads of 20 to 50 N against YG6 cemented carbide.The experimental results show that the friction coefficients of all samples increase with increasing load.The 25vol%composite exhibits the lowest friction coefficient(0.1669-0.2716),while the 60vol%composite exhibits the highest(0.3237-0.3990),with the 6092 aluminum alloy falling between the two.The wear volume and specific wear rate also increase with load,but the composites with a higher Si C content demonstrate smaller increments,with the 60vol%composite exhibiting superior wear resistance.Under a 30 N load,the wear scars of the 60vol%composite show a significant increase in the contents of elements such as C,Co,W,and O,indicating more severe wear of the counterpart material.Scanning electron microscopy(SEM)reveals wear mechanisms including adhesive wear,two-body sliding and three-body rolling wear of particles,and delamination.
基金the financial support from the National Natural Science Foundation of China(Nos.U2233212,52375036,62303030 and 62403028)the Postdoctoral Fellowship Program of CPSF,China(Nos.GZC20242158 and GZC20233377)+1 种基金Open Fund of State Key Laboratory of Mechanical Transmission for Advanced Equipment,China(No.SKLMT-MSKFKT-202421)the Fundamental Research Funds for the Central Universities,China。
文摘Internal leakage caused by wear in hydraulic spool valves represents a critical failure mode that threatens the performance of aircraft hydraulic systems and compromises flight safety.Due to complex operational loads and time-varying material properties,the relationship between wear state and Remaining Useful Life(RUL)is nonlinear.Consequently,accurately modeling this wear remains a significant challenge,as existing research often neglects the coupled effects of material properties,stress conditions,and dynamic lubrication parameters.To address this issue,this study proposes a novel framework integrating physical mechanisms with stochastic processes to enhance wear degradation modelling and RUL prediction.First,a Physics-of-Failure(PoF)model is developed based on Archard's wear theory,which characterizes tribological behavior at the contact interface and accounts for the effects of lubrication and load conditions.Next,a Gamma process is introduced to model the degradation trajectory,with physical parameters guiding the specification of the time-scale function.A Bayesian expectation–maximization algorithm is employed to estimate and update the model parameters.Finally,a numerical simulation and case study on spool valves are conducted to demonstrate the effectiveness of the proposed model.The cross-validation results confirmed that the introduction of random effects effectively reduces the impact of uncertainty on physics-informed modeling.This study offers a systematic solution to RUL prediction for hydraulic systems.
基金supported by the National Natural Science Foundation of China(No.51871243)the National Key Laboratory of Strength and Structural Integrity,China(No.ASSIKFJJ202304001)+3 种基金the State Key Laboratory of Precision Blasting and Hubei Key Laboratory of Blasting Engineering,China(No.PBSKL2022C01)the Guangdong-Hong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology,China(No.HT-CSNS-DG-CD-0092/2021)the Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province,China(No.22kfgk06)the Hubei Longzhong Laboratory,China(No.2022KF-08)。
文摘Laser remelting(LR)was used as an auxiliary post-treatment process for the Ti6Al4V titanium alloys fabricated by laser powder bed fusion(LPBF).Optical microscope(OM),scanning electron microscope(SEM)and electron back scattering diffraction(EBSD)observations showed that the grains in melted zone(MZ)transformed into equiaxial grains with an average size of 1.31μm,and the grains in heat affected zone(HAZ)were refined.Moreover,the texture intensity dropped significantly from 13.86 to 6.35 in MZ and 10.79 in HAZ.The temperature gradient(G)to solidification rate(R)ratio decreased when the laser scanning speed slowed down to a certain extent in the LR process,which effectively improved the highly preferred orientation and filled the hole defects in the surface of LPBF-Ti6Al4V.Furthermore,the hardness,wear resistance and corrosion resistance of the surface of the LPBF samples were improved by LR treatment.
基金co-supported by the Tsinghua University Initiative Scientific Research Program,China(No.20244186005)the Science Center for Gas Turbine Project,China(No.P2022-A-IV-002-003)the National Natural Science Foundation of China(No.92060108)。
文摘Diffusion shaped film cooling holes with compound-angle diffuser structures exhibit superior cooling performance,which have gradually been applied in turbine blades of the advanced aeroengines.In our previous research,the method of Servo Scanning three-dimensional Electrical Discharge Machining(SS-3D EDM)has been proven effective for high-precision machining of complex 3D cavities,offering notable advantages such as low tool cost,automatic compensation of electrode wear,and high machining flexibility.However,using tubular electrodes in SS-3D EDM,challenges persist under the conditions of the large layer depth.The lateral discharge phenomenon of tubular electrodes causes significant deformation at the electrode tip,increases the risk of lateral collisions,and complicates the accurate calculation of electrode wear length.To address these limitations,this research proposes a Trajectory Servo Scanning three-dimensional Electrical Discharge Machining(TSS-3D EDM)process.Axial servo motion of tubular electrode is used to maintain the discharge gap of electrode bottom,and an innovative trajectory servo motion along the tangential orientation is introduced to stabilize the lateral discharge gap,enabling automatic compensation for tool wear at the rotating electrode tip.The effect of servo control parameters on machining depth accuracy is analyzed.Furthermore,a method for electrode wear length calculation is proposed based on the voltage signals of discharge gaps.An estimation method for the electrode wear coefficient is presented.Machining experiments on superalloys validate the effectiveness and capabilities of the TSS-3D EDM method by fabricating fan-shaped and conical diffusion shaped film cooling holes.The results show that the calculation error of tubular electrode wear length<5%,the dimensional error of hole profile dimensions as 4%–6%,the repeatability error<±4μm,and the material removal rate up to 0.664 mm^(3)/min using tubular electrodes with an outer diameter of 0.4 mm.
文摘本文探讨Art to Wear即“可以穿的艺术”,其中大部分作品为服装,少量作品是帽子和首饰。通过分析Art to Wear代表艺术家,解读Art to Wear艺术作品,从而探讨美国20世纪60年代到80年代女性艺术家群体如何以艺术为媒介对自身经历进行叙述性表现。60年代末70年代初处于美国女性主义的第二次浪潮,众多美国名校的年轻白人女大学生,不断为女性的参政、就业、医疗、最低工资等争取更多的权利,而到了80年代遭到美国保守主义的强烈打击,追求自由平等的女性主义运动跌入低谷。第二次女性主义运动的跌宕正是Art to Wear艺术运动的发展时期,艺术学院在读青年女生们发起Art to Wear艺术运动,她们在保守主义与激进主义的影响下寻求精神、生活的平衡,极力反叛女性束身塑形来博得男性视觉愉悦、通过同性的嫉妒来肯定自身价值。她们对家庭、事业、社会地位开始深思,通过作品叙述对社会性别与身份认定的迷茫,表达保守与激进思想的内心纠结。
文摘In-situ formed high Mn steel coating reinforced by carbides was formed by laser surface alloying(LSA).Laser alloyed layers on 1Cr18Ni9Ti steel with Mn+W_(2)C(specimen A),Mn+NiWC(specimen B)and Mn+SiC(specimen C)powders were fabricated to improve the wear and corrosion behavior of 1Cr18Ni9Ti steel blades in high speed mixers.Microstructure evolution,phases,element distribution,microhardness,wear and corrosion behavior of the laser alloyed layers were investigated.Results indicated that high Mn steel matrix composites with undissolved W_(2)C,WC and other in-situ formed carbides were formed by LSA with Mn+W_(2)C and Mn+NiWC while SiC totally dissolved into the high Mn matrix when adding Mn+SiC.Ni as the binding phase in Ni-WC powder decreased the crack sensitivity of the alloyed layer as compared with the addition of W_(2)C powder.An improvement in average microhardness was achieved in the matrix in specimen A,B and C,with the value of 615,602 and 277 HV_(0.5),while that of the substrate was 212 HV_(0.5).The increase of microhardness,wear and corrosion resistance is highly corelated to microstructure,formed phases,type and content of carbides,micro-hardness and toughness of the alloyed layers.
基金National Natural Science Foundation of China(52071126)Natural Science Foundation of Tianjin City,China(22JCQNJC01240)+2 种基金Central Guidance on Local Science and Technology Development Fund of Hebei Province(226Z1009G)Special Funds for Science and Technology Innovation in Hebei(2022X19)Anhui Provincial Natural Science Foundation(2308085ME135)。
文摘Co-based alloy coating was prepared on Zr alloy using laser melting and cladding technique to study the difference in the high-temperature oxidation behavior between pure metal Co coatings and Co-T800 alloy coatings,as well as the wear resistance of the coatings.Besides,the effect of changing the laser melting process on the coatings was also investigated.The oxidation mass gain at 800–1200℃and the high-temperature oxidation behavior during high-temperature treatment for 1 h of two coated Zr alloy samples were studied.Results show that the Co coating and the Co-T800 coating have better resistance against high-temperature oxidation.After oxidizing at 1000℃for 1 h,the thickness of the oxide layer of the uncoated sample was 241.0μm,whereas that of the sample with Co-based coating is only 11.8–35.5μm.The friction wear test shows that the depth of the abrasion mark of the coated sample is only 1/2 of that of the substrate,indicating that the hardness and wear resistance of the Zr substrate are greatly improved.The disadvantage of Co-based coatings is the inferior corrosion resistance in 3.5wt%NaCl solution.
