We present the design of micro-helix metamaterial supporting high sound absorption characteristic by 3D printing. The sample structure which is fabricated out of polylactide （PLA） material, many micro-helix are arra...We present the design of micro-helix metamaterial supporting high sound absorption characteristic by 3D printing. The sample structure which is fabricated out of polylactide （PLA） material, many micro-helix are arranged by periodic arrays on XY plane. Experiment measurement results show that different geometrical dimensions of helix vestibule and cavity depth have a great effect on sound absorption coefficient. Physical mechanism depends on the friction and viscosity between the air and the helix vestibule. This work shows great potential of micro-structure metamaterial in noise control applications require light weight and large rigid of sound absorption.展开更多
重点研究了聚焦离子束的相关原理和应用。利用聚焦离子束应力引入致形变(Focused Ion Beam Stress-Introduced Deformation,FIB-SID)技术与常规微加工工艺相结合,制备微型金属无源螺旋电感的设计方法和工艺流程,并对其电学性能进行初步...重点研究了聚焦离子束的相关原理和应用。利用聚焦离子束应力引入致形变(Focused Ion Beam Stress-Introduced Deformation,FIB-SID)技术与常规微加工工艺相结合,制备微型金属无源螺旋电感的设计方法和工艺流程,并对其电学性能进行初步高频测试。首先在SOI(Silicon-on-Insulator)基片上通过光刻、溅射以及各项同性刻蚀等常规工艺制得悬浮的金属悬臂梁,再利用FIB刻蚀原理进行应力引入,通过控制注入离子剂量、FIB应力引入的次数、FIB扫描的间距等试验参数制得不同尺寸结构的三维螺旋金属无源电感。后,采用安捷伦网络分析仪与微波探针台,使用GSG结构及相应的去嵌方法,对微型金属螺线管电感进行了高频测试。得出了三维螺旋微纳电感的电感值、品质因子、电压驻波比、回波损耗随频率变化关系。展开更多
A graphene nanoribbon （GNR） has two basic configurations when winding on the outer surface of a carbon nanotube （CNT）： helix and scroll. Here the transformation between the two configurations is studied utilizing...A graphene nanoribbon （GNR） has two basic configurations when winding on the outer surface of a carbon nanotube （CNT）： helix and scroll. Here the transformation between the two configurations is studied utilizing molecular dynamics simulations. The energy barrier during the transformation as well as its relationship with the interfacial energy and the radius of CNT are investigated. Our work offers further insights into the formation of desirable helix/scroll of GNR winding on nanotubes or nanowires, and thus can enable novel design of potential graphene-based electronics.展开更多
Microorganism cells could be used as templates during fabrication of magnetic or conductive microstructures in different standard shapes. In this paper, feasibility of magnetizing microorganism cells by sol-gel method...Microorganism cells could be used as templates during fabrication of magnetic or conductive microstructures in different standard shapes. In this paper, feasibility of magnetizing microorganism cells by sol-gel method, which is to coat cells of Spirulina (a type of natural micro-helical microorganism) with the ferrite (a kind of magnetic material), was discussed and investigated. Then the cell form, components and the phase structure were observed and analyzed using various tools including optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray detector (EDX), transmission electron microscopy (TEM), and X-ray diffraction analysis (XRD). Results showed that spirulina cells could be coated with ferrite after the sol-gel process, with the shape of natural helixes well kept, that the components of different sampling points on the surface layer were consistent and the thickness of layer was uniform, and that the type of the surface ferrite layer formed was cubic Fe3O4. It was also observed that there were nano-particles yielded in the cells and certain deposit on the walls between cells. The kinetics of the cell magnetization technology by sol-gel was also discussed.展开更多
基金supported by the National Natural Science Foundation of China (11704314 and 11474230)the Fundamental Research Funds for the Central Universities (3102016QD056) for financial support
文摘We present the design of micro-helix metamaterial supporting high sound absorption characteristic by 3D printing. The sample structure which is fabricated out of polylactide （PLA） material, many micro-helix are arranged by periodic arrays on XY plane. Experiment measurement results show that different geometrical dimensions of helix vestibule and cavity depth have a great effect on sound absorption coefficient. Physical mechanism depends on the friction and viscosity between the air and the helix vestibule. This work shows great potential of micro-structure metamaterial in noise control applications require light weight and large rigid of sound absorption.
文摘重点研究了聚焦离子束的相关原理和应用。利用聚焦离子束应力引入致形变(Focused Ion Beam Stress-Introduced Deformation,FIB-SID)技术与常规微加工工艺相结合,制备微型金属无源螺旋电感的设计方法和工艺流程,并对其电学性能进行初步高频测试。首先在SOI(Silicon-on-Insulator)基片上通过光刻、溅射以及各项同性刻蚀等常规工艺制得悬浮的金属悬臂梁,再利用FIB刻蚀原理进行应力引入,通过控制注入离子剂量、FIB应力引入的次数、FIB扫描的间距等试验参数制得不同尺寸结构的三维螺旋金属无源电感。后,采用安捷伦网络分析仪与微波探针台,使用GSG结构及相应的去嵌方法,对微型金属螺线管电感进行了高频测试。得出了三维螺旋微纳电感的电感值、品质因子、电压驻波比、回波损耗随频率变化关系。
基金supported by the National Natural Science Foundation of China(NSFC)(11272327 and 11023001)mainly supported by the Supercomputing Center of Chinese Academy of Sciences(SCCAS)
文摘A graphene nanoribbon （GNR） has two basic configurations when winding on the outer surface of a carbon nanotube （CNT）： helix and scroll. Here the transformation between the two configurations is studied utilizing molecular dynamics simulations. The energy barrier during the transformation as well as its relationship with the interfacial energy and the radius of CNT are investigated. Our work offers further insights into the formation of desirable helix/scroll of GNR winding on nanotubes or nanowires, and thus can enable novel design of potential graphene-based electronics.
基金the National Natural Science Foundation of China (Grant No. 59975007)the National Hi-Tech Research and Development Program of China (863 Program) (Grant No. 2001AA421120)the Innovative Fund of Beihang University in 2005 (Grant No.200505)
文摘Microorganism cells could be used as templates during fabrication of magnetic or conductive microstructures in different standard shapes. In this paper, feasibility of magnetizing microorganism cells by sol-gel method, which is to coat cells of Spirulina (a type of natural micro-helical microorganism) with the ferrite (a kind of magnetic material), was discussed and investigated. Then the cell form, components and the phase structure were observed and analyzed using various tools including optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray detector (EDX), transmission electron microscopy (TEM), and X-ray diffraction analysis (XRD). Results showed that spirulina cells could be coated with ferrite after the sol-gel process, with the shape of natural helixes well kept, that the components of different sampling points on the surface layer were consistent and the thickness of layer was uniform, and that the type of the surface ferrite layer formed was cubic Fe3O4. It was also observed that there were nano-particles yielded in the cells and certain deposit on the walls between cells. The kinetics of the cell magnetization technology by sol-gel was also discussed.
