Stab resistance body armor（SRBA）is essential in protecting people from knife injuries.The protective parts of traditional SRBA are made of multi-layered ultra-high molecular weight polyethylene（UHMWPE）,which cause...Stab resistance body armor（SRBA）is essential in protecting people from knife injuries.The protective parts of traditional SRBA are made of multi-layered ultra-high molecular weight polyethylene（UHMWPE）,which causes heavy heat stress for people wearing it.The protective parts of SRBA manufactured using laser sintering（LS）3D printing technology provide high manufacturing flexibility and low weight.Two different structures,plain plate and pyramid-structured plate,were investigated.The pyramid structure showed much higher stab resistance property then the plain plate,because of the angle and thickness effects.This is the first effort applying the LS technology and polyamide（PA）material（PA3200）on SRBA.By applying the pyramid structure on the protective layer of the SRBA,the total weight could reduce 30%-40%.展开更多
The infrared absorption spectra of different superconducting phase of high Tc super conductor Bi-Sb-Sr-Ca-Cu-O have been measured . The results show that only in the range of 400cm-1 -700cm-1,there is a group of peaks...The infrared absorption spectra of different superconducting phase of high Tc super conductor Bi-Sb-Sr-Ca-Cu-O have been measured . The results show that only in the range of 400cm-1 -700cm-1,there is a group of peaks which changes with different superconducting phases.According to group theory and infrared spectra of CuO, this group of peaks could be assigned to be the [CuO6]octahedron, the [CuO5] pyramid and the [CuO4]plane quadrilateral,but not CU-O plane or CU-O chain. Furthermore, the quasi-three dimensional Cu-O layers consisting of [CuO5] pyramids and proper coupling between them are essential factor for high Tc. It seems that the weaker compling of layers, the higher Tc展开更多
基金Supported by the Independent Research Project of State Key Laboratory of Explosion Science and Technology(YBKT16-13)Beijing Institute of Technology Research Fund Program for Young Scholars(2-205205-2014)National Key Rsearch Program(2016YFC0802801-4)
文摘Stab resistance body armor（SRBA）is essential in protecting people from knife injuries.The protective parts of traditional SRBA are made of multi-layered ultra-high molecular weight polyethylene（UHMWPE）,which causes heavy heat stress for people wearing it.The protective parts of SRBA manufactured using laser sintering（LS）3D printing technology provide high manufacturing flexibility and low weight.Two different structures,plain plate and pyramid-structured plate,were investigated.The pyramid structure showed much higher stab resistance property then the plain plate,because of the angle and thickness effects.This is the first effort applying the LS technology and polyamide（PA）material（PA3200）on SRBA.By applying the pyramid structure on the protective layer of the SRBA,the total weight could reduce 30%-40%.
文摘The infrared absorption spectra of different superconducting phase of high Tc super conductor Bi-Sb-Sr-Ca-Cu-O have been measured . The results show that only in the range of 400cm-1 -700cm-1,there is a group of peaks which changes with different superconducting phases.According to group theory and infrared spectra of CuO, this group of peaks could be assigned to be the [CuO6]octahedron, the [CuO5] pyramid and the [CuO4]plane quadrilateral,but not CU-O plane or CU-O chain. Furthermore, the quasi-three dimensional Cu-O layers consisting of [CuO5] pyramids and proper coupling between them are essential factor for high Tc. It seems that the weaker compling of layers, the higher Tc
