Earth penetration weapon （EPW） is applicable for attacking underground targets protected by reinforced concrete and rocks. With increasing impact velocity, the mass loss/abrasion of penetrator increases, which signi...Earth penetration weapon （EPW） is applicable for attacking underground targets protected by reinforced concrete and rocks. With increasing impact velocity, the mass loss/abrasion of penetrator increases, which significandy decreases the penetration efficiency due to the change of nose shape. The abrasion may induce instability of the penetrator, and lead to failure of its structure. A common disadvantage, i.e. dependence on corresponding experimen- tal results, exists in all the available formulae, which limits their ranges of application in estimating the mass loss of penetrator. In this paper, we conduct a parametric study on the mass loss of penetrator, and indicate that the mass loss of penetrator can be determined by seven variables, i.e., the initial impact velocity, initial nose shape, melting heat, shank diameter of projectile and density and strength of target as well as the aggregate hardness of target. Further discussion on factors dominant in the mass abrasion of penetrator are given, which may be helpful for optimizing the target or the projectile for defensive or offensive objectives, respectively.展开更多
The millimeter-wave frequency band(30~300 GHz)has received significant attention.Millimeter-wave frequencies have been used for backhaul,cell communication,and other high speed communication.With the advent of 5G comm...The millimeter-wave frequency band(30~300 GHz)has received significant attention.Millimeter-wave frequencies have been used for backhaul,cell communication,and other high speed communication.With the advent of 5G communication,millimeter-wave frequencies such as 60-GHz band have been attracting attention as possible candidate for next-generation wireless networks.The traditional application for 60-GHz band is point-to-point communication.Some typical scenarios have been cited in a recent 5G white paper.There exist some traditional channel models for 3G and 4G communication.However,5G has a new channel model(the outdoor-to indoor channel model,or O2I)that has not been clearly studied.Some conventional channel measurements have been conducted for this new band.Two measurement systems in the 60-GHz band for penetration loss and small-scale measurement for different scenarios are presented.By analyzing our measurement data,we can prove that the O2I channel does not generate new paths and only add some material penetration loss.展开更多
基金supported by the National Natural Science Foundation of China (10672152)the Science Foundation of China Academy of Engineering Physics (2009A0201009)the Innovation Fund of the Institute of Structural Mechanics,CAEP (09CXJ05)
文摘Earth penetration weapon （EPW） is applicable for attacking underground targets protected by reinforced concrete and rocks. With increasing impact velocity, the mass loss/abrasion of penetrator increases, which significandy decreases the penetration efficiency due to the change of nose shape. The abrasion may induce instability of the penetrator, and lead to failure of its structure. A common disadvantage, i.e. dependence on corresponding experimen- tal results, exists in all the available formulae, which limits their ranges of application in estimating the mass loss of penetrator. In this paper, we conduct a parametric study on the mass loss of penetrator, and indicate that the mass loss of penetrator can be determined by seven variables, i.e., the initial impact velocity, initial nose shape, melting heat, shank diameter of projectile and density and strength of target as well as the aggregate hardness of target. Further discussion on factors dominant in the mass abrasion of penetrator are given, which may be helpful for optimizing the target or the projectile for defensive or offensive objectives, respectively.
文摘The millimeter-wave frequency band(30~300 GHz)has received significant attention.Millimeter-wave frequencies have been used for backhaul,cell communication,and other high speed communication.With the advent of 5G communication,millimeter-wave frequencies such as 60-GHz band have been attracting attention as possible candidate for next-generation wireless networks.The traditional application for 60-GHz band is point-to-point communication.Some typical scenarios have been cited in a recent 5G white paper.There exist some traditional channel models for 3G and 4G communication.However,5G has a new channel model(the outdoor-to indoor channel model,or O2I)that has not been clearly studied.Some conventional channel measurements have been conducted for this new band.Two measurement systems in the 60-GHz band for penetration loss and small-scale measurement for different scenarios are presented.By analyzing our measurement data,we can prove that the O2I channel does not generate new paths and only add some material penetration loss.
