A new concept of the global magnetospheric resonator is suggested for fast magnetosonic waves in which the role of the resonator is played by the near part of the plasma sheet. It is shown that the magnetosonic wave i...A new concept of the global magnetospheric resonator is suggested for fast magnetosonic waves in which the role of the resonator is played by the near part of the plasma sheet. It is shown that the magnetosonic wave is confined in this region of the magnetosphere throughout its boundaries. The representative value of the resonator's eigenfrequency estimated at f ≈ 1 mHz is in good agreement with observational data on ultraThe theory explains the ground-based localization of the oscillations observed in the midnight-morning sector of the high-latitude magnetosphere.展开更多
Friction remains as the primary mode of energy dissipation and components wear,and achieving superlubricity shows high promise in energy conservation and lifetime wear protection.The results in this work demonstrate t...Friction remains as the primary mode of energy dissipation and components wear,and achieving superlubricity shows high promise in energy conservation and lifetime wear protection.The results in this work demonstrate that direct superlubricity combined with superlow wear can be realized for steel/Si_(3)N_(4)contacts on engineering scale when polyhydroxy alcohol solution was selectively modified by amino group.Macroscopic direct superlubricity occurs because 3-amino-1,2-propanediol molecules at the friction interface could be induced to rotate and adsorb vertically on the friction surface,forming in-situ thick and dense molecular films to passivate the asperity contacts.Furthermore,amino modification is also conducive to improving the lubrication state from boundary to mixed lubrication regime by strengthening the intermolecular hydrogen bonding interaction,presenting enhanced load-bearing capability and reduced direct solid asperity contacts.Thus,direct superlow average friction of 0.01 combined with superlow wear are achieved simultaneously.The design principle of direct superlubricity and superlow wear in this work indeed offers an effective strategy to fundamentally improve energy efficiency and provide lifetime wear protection for moving mechanical assemblies.展开更多
近年来,高硬度、低摩擦、高耐磨性的类金刚石(Diamond like carbon,DLC)膜引起了国内外学术界和工业界极大的研究兴趣,尤其是它的超低摩擦行为。首先从宏观和微观角度分析了DLC膜超低摩擦的起源,研究发现DLC膜的微观结构和测试环境是影...近年来,高硬度、低摩擦、高耐磨性的类金刚石(Diamond like carbon,DLC)膜引起了国内外学术界和工业界极大的研究兴趣,尤其是它的超低摩擦行为。首先从宏观和微观角度分析了DLC膜超低摩擦的起源,研究发现DLC膜的微观结构和测试环境是影响DLC膜实现超低摩擦的主要因素,而DLC膜的微观结构由其制备工艺决定。然后系统讨论了制备工艺(包括制备方法、反应气源、掺杂元素和基体材料等)和测试环境(包括真空与干燥惰性气体环境、潮湿环境、高温环境、载荷和滑动速度等)对DLC膜超低摩擦行为的影响规律。最后归纳分析了目前对DLC膜超低摩擦机理的几种解释,指出DLC膜作为超低摩擦材料仍需解决的问题及未来的研究趋势。展开更多
The achievement of a superlubric state with vanishing friction and negligible wear has important applications in minimizing energy dissipation and prolonging the service life of moving mechanical systems.However,the s...The achievement of a superlubric state with vanishing friction and negligible wear has important applications in minimizing energy dissipation and prolonging the service life of moving mechanical systems.However,the search for a superlubricious oil system applicable to industrial fields remains a major challenge.In this work,we demonstrate for the first time that precisely employing polyether modification for silicone oil molecules could induce direct superlubricity and superlow wear for engineering steel tribopairs.Superlubricity originates from the fact that polyether-modified silicone oil(PESO)can effectively employ polyether functional groups to interact with friction surfaces,during which a complex tribochemical reaction process can be induced under the catalytic role of friction,where an organic lubricious film composed mainly of carbon,silicon and oxygen can be induced in situ,which can not only effectively passivate friction surfaces but also enable superlubric sliding by virtue of its easy-to-shear nature.Furthermore,iron oxides and chromium oxides could also be confirmed to be distributed within the tribofilm,which is desirable for increasing the load-bearing capability of the tribofilm and toughness.Thus,a remarkable superlubricity of 0.01 without running-in combined with superlow wear was realized at the same time.The results of this work show high promise in promoting the industrial use of oil superlubricity and revolutionizing the development of mechanical systems.展开更多
基金Supported by the Russian Foundation for Basic Research (No. 04-05-64321)RFBR-GFEN (No. 02-05-39020)the China- Russia Joint Research Center on Space WeatherChinese Academy of Sciences
文摘A new concept of the global magnetospheric resonator is suggested for fast magnetosonic waves in which the role of the resonator is played by the near part of the plasma sheet. It is shown that the magnetosonic wave is confined in this region of the magnetosphere throughout its boundaries. The representative value of the resonator's eigenfrequency estimated at f ≈ 1 mHz is in good agreement with observational data on ultraThe theory explains the ground-based localization of the oscillations observed in the midnight-morning sector of the high-latitude magnetosphere.
基金the National Key R&D Program of China(No.2022YFB3809000)Natural Science Foundation of Chongqing,China(No.2023NSCQ-MSX3029)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515111005)the Fundamental Research Funds for the Central Universities of China(No.G2022KY05108).
文摘Friction remains as the primary mode of energy dissipation and components wear,and achieving superlubricity shows high promise in energy conservation and lifetime wear protection.The results in this work demonstrate that direct superlubricity combined with superlow wear can be realized for steel/Si_(3)N_(4)contacts on engineering scale when polyhydroxy alcohol solution was selectively modified by amino group.Macroscopic direct superlubricity occurs because 3-amino-1,2-propanediol molecules at the friction interface could be induced to rotate and adsorb vertically on the friction surface,forming in-situ thick and dense molecular films to passivate the asperity contacts.Furthermore,amino modification is also conducive to improving the lubrication state from boundary to mixed lubrication regime by strengthening the intermolecular hydrogen bonding interaction,presenting enhanced load-bearing capability and reduced direct solid asperity contacts.Thus,direct superlow average friction of 0.01 combined with superlow wear are achieved simultaneously.The design principle of direct superlubricity and superlow wear in this work indeed offers an effective strategy to fundamentally improve energy efficiency and provide lifetime wear protection for moving mechanical assemblies.
文摘近年来,高硬度、低摩擦、高耐磨性的类金刚石(Diamond like carbon,DLC)膜引起了国内外学术界和工业界极大的研究兴趣,尤其是它的超低摩擦行为。首先从宏观和微观角度分析了DLC膜超低摩擦的起源,研究发现DLC膜的微观结构和测试环境是影响DLC膜实现超低摩擦的主要因素,而DLC膜的微观结构由其制备工艺决定。然后系统讨论了制备工艺(包括制备方法、反应气源、掺杂元素和基体材料等)和测试环境(包括真空与干燥惰性气体环境、潮湿环境、高温环境、载荷和滑动速度等)对DLC膜超低摩擦行为的影响规律。最后归纳分析了目前对DLC膜超低摩擦机理的几种解释,指出DLC膜作为超低摩擦材料仍需解决的问题及未来的研究趋势。
基金the Natural Science Basic Research Program of Shaanxi(Program No.2024JC-YBQN-0466)the China Postdoctoral Science Foundation(Grant No.2023M742841)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515111005)the Natural Science Foundation of Chongqing,China(Grant No.2023NSCQ-MSX3029).
文摘The achievement of a superlubric state with vanishing friction and negligible wear has important applications in minimizing energy dissipation and prolonging the service life of moving mechanical systems.However,the search for a superlubricious oil system applicable to industrial fields remains a major challenge.In this work,we demonstrate for the first time that precisely employing polyether modification for silicone oil molecules could induce direct superlubricity and superlow wear for engineering steel tribopairs.Superlubricity originates from the fact that polyether-modified silicone oil(PESO)can effectively employ polyether functional groups to interact with friction surfaces,during which a complex tribochemical reaction process can be induced under the catalytic role of friction,where an organic lubricious film composed mainly of carbon,silicon and oxygen can be induced in situ,which can not only effectively passivate friction surfaces but also enable superlubric sliding by virtue of its easy-to-shear nature.Furthermore,iron oxides and chromium oxides could also be confirmed to be distributed within the tribofilm,which is desirable for increasing the load-bearing capability of the tribofilm and toughness.Thus,a remarkable superlubricity of 0.01 without running-in combined with superlow wear was realized at the same time.The results of this work show high promise in promoting the industrial use of oil superlubricity and revolutionizing the development of mechanical systems.
