A deceptive pull-off jamming method to terminal guidance radar is put forward in this paper.The design rules about the important jamming parameters are discussed in detail,including the number of the decoy targets in ...A deceptive pull-off jamming method to terminal guidance radar is put forward in this paper.The design rules about the important jamming parameters are discussed in detail,including the number of the decoy targets in range dimension,the velocity of the range gate pull-off,and the number of the decoy targets in velocity dimension and the velocity of the Doppler frequency pull-off.Also,the steps to design these parameters are brought out.The rules and design procedure discussed in this paper have important meaning for the choice of the reasonable jamming parameters in the practical applications,which can help to obtain good jamming effect.展开更多
A microtribometer is used to measure and compare pull-off forces and friction forces exerted on (a) micro-dimpled silicon surfaces, (b) bare silicon surfaces, and (c) octadecyltrichlorosilane (OTS) treated sil...A microtribometer is used to measure and compare pull-off forces and friction forces exerted on (a) micro-dimpled silicon surfaces, (b) bare silicon surfaces, and (c) octadecyltrichlorosilane (OTS) treated silicon surfaces at different relative humidity (RH) levels separately. It is found that above a critical RH level, the capillary pull-off force increases abruptly and that the micro-dimple textured surface has a lower critical RH value as well as a higher pull-off force value than the other two surfaces. A micro topography parameter, namely sidewall area ratio, is found to play a major role in controlling the capillary pull-off force. Furthermore, micro-dimpled silicon surface is also proved to be not sensitive to variation in RH level, and can realize a stable and decreased friction coefficient compared with un-textured silicon surfaces. The reservoir-like function of micro dimples is considered to weaken or avoid the breakage effect of liquid bridges at different RH levels, thereby maintaining a stable frictional behaviour.展开更多
Adhesive interaction is a ubiquitous phenomenon in various aspects of nature and engineering,driving extensive research on adhesive contact over past decades.This brief review surveys adhesive contact models at the si...Adhesive interaction is a ubiquitous phenomenon in various aspects of nature and engineering,driving extensive research on adhesive contact over past decades.This brief review surveys adhesive contact models at the single-asperity level.Attention has been focused on how adhesive interaction is accounted for in models of normal contact,inclined contact,and contact with rolling tendency,and hence the corresponding interfacial tractions have been outlined.Perspectives on remaining challenges in adhesive contact mechanics have also been summarized.展开更多
Pre-strain and pre-stress in soft materials have significant effects on their adhesive behavior,thereby influencing their functions and applications.Whereas prior theoretical studies on the adhesion of pre-strained el...Pre-strain and pre-stress in soft materials have significant effects on their adhesive behavior,thereby influencing their functions and applications.Whereas prior theoretical studies on the adhesion of pre-strained elastomers predominantly rely on fracture mechanics frameworks based on the assumption of short-range forces,this study models surface interactions using the Lennard-Jones potential,thereby elucidating more intricate details of the adhesive behavior.The results of the proposed model are initially validated through finite element simulations and the analytical models in the literature.Subsequently,the effects of substrate pre-stretch on the adhesive behavior,including the pull-off force,JKR-Bradley transition,jump-in and jump-out instabilities,surface profile,and pressure distribution,are revealed by the proposed model.Based on the‘semi-rigid’theory(SRT),an analytical solution is derived to predict the displacement and central gap at the jump-in point.A modified Tabor parameter that incorporates the substrate pre-stretch effect is also proposed.The JKR-Bradley transition characterized by this modified parameter coincides with the unstretched case.This study offers new insights into understanding the adhesive behavior of pre-stretched elastomers.展开更多
基金Sponsored by National Basic Research Program of China (6139001012)
摘要A deceptive pull-off jamming method to terminal guidance radar is put forward in this paper.The design rules about the important jamming parameters are discussed in detail,including the number of the decoy targets in range dimension,the velocity of the range gate pull-off,and the number of the decoy targets in velocity dimension and the velocity of the Doppler frequency pull-off.Also,the steps to design these parameters are brought out.The rules and design procedure discussed in this paper have important meaning for the choice of the reasonable jamming parameters in the practical applications,which can help to obtain good jamming effect.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 50575123 and 50730007)China Scholarship Council (CSC) and German Research Foundation (DFG)
摘要A microtribometer is used to measure and compare pull-off forces and friction forces exerted on (a) micro-dimpled silicon surfaces, (b) bare silicon surfaces, and (c) octadecyltrichlorosilane (OTS) treated silicon surfaces at different relative humidity (RH) levels separately. It is found that above a critical RH level, the capillary pull-off force increases abruptly and that the micro-dimple textured surface has a lower critical RH value as well as a higher pull-off force value than the other two surfaces. A micro topography parameter, namely sidewall area ratio, is found to play a major role in controlling the capillary pull-off force. Furthermore, micro-dimpled silicon surface is also proved to be not sensitive to variation in RH level, and can realize a stable and decreased friction coefficient compared with un-textured silicon surfaces. The reservoir-like function of micro dimples is considered to weaken or avoid the breakage effect of liquid bridges at different RH levels, thereby maintaining a stable frictional behaviour.
基金National Natural Science Foundation of China,12172249Ganyun Huang,12192212Ganyun Huang,Innovative Research Group Project of the National Natural Science Foundation of China,12021002。
摘要Adhesive interaction is a ubiquitous phenomenon in various aspects of nature and engineering,driving extensive research on adhesive contact over past decades.This brief review surveys adhesive contact models at the single-asperity level.Attention has been focused on how adhesive interaction is accounted for in models of normal contact,inclined contact,and contact with rolling tendency,and hence the corresponding interfacial tractions have been outlined.Perspectives on remaining challenges in adhesive contact mechanics have also been summarized.
基金Project supported by the National Natural Science Foundation of China(No.12321002)the 111 Project of China(No.B21034)。
摘要Pre-strain and pre-stress in soft materials have significant effects on their adhesive behavior,thereby influencing their functions and applications.Whereas prior theoretical studies on the adhesion of pre-strained elastomers predominantly rely on fracture mechanics frameworks based on the assumption of short-range forces,this study models surface interactions using the Lennard-Jones potential,thereby elucidating more intricate details of the adhesive behavior.The results of the proposed model are initially validated through finite element simulations and the analytical models in the literature.Subsequently,the effects of substrate pre-stretch on the adhesive behavior,including the pull-off force,JKR-Bradley transition,jump-in and jump-out instabilities,surface profile,and pressure distribution,are revealed by the proposed model.Based on the‘semi-rigid’theory(SRT),an analytical solution is derived to predict the displacement and central gap at the jump-in point.A modified Tabor parameter that incorporates the substrate pre-stretch effect is also proposed.The JKR-Bradley transition characterized by this modified parameter coincides with the unstretched case.This study offers new insights into understanding the adhesive behavior of pre-stretched elastomers.