For measuring velocity and impacting position of single fragment of warhead,a non-contact measuring method is proposed,in which a six-light-screen array,a position indicator,a multi-channel chronograph and a computer ...For measuring velocity and impacting position of single fragment of warhead,a non-contact measuring method is proposed,in which a six-light-screen array,a position indicator,a multi-channel chronograph and a computer are used.The principle of measurement is described.The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters.When the fragment flies through the light screen array,the time of passing through each of the screens is recorded by the multi-channel chronograph.According to the time data and the geometrical parameters of the array,the velocity vector and the location of the fragment can be calculated immediately.The presented method can be used to locate the fragment and to measure the real velocity on its flying direction.It can also be used to measure the velocity of a fragment swarm after the system is engineered further.展开更多
Recently,piezoelectric/triboelectric nanogenerators based on piezoelectric composite materials have been intensively studied to achieve high electrical output perfomiance.In this work,flexible BaTiO_(3)(BT)/PDMS nanoc...Recently,piezoelectric/triboelectric nanogenerators based on piezoelectric composite materials have been intensively studied to achieve high electrical output perfomiance.In this work,flexible BaTiO_(3)(BT)/PDMS nanocomposite films with various sizes and concentrations were fabricated and used as the nanogenerators.The influence of dielectric properties on the electrical output of nanogenerators was studied as well as the structure of the composites.The dielectric constant increased from 6.5 to 8 with the concentration of BT nanoparticles and decreased with the frequency from 10^(2) to 10^(6) Hz.Furthermore,the dielectric constant showed 11% decrease with the temperature range from 30 to 180℃.It was found that the concentration of BT nanoparticles has promoted the electrical output of nanogenerators.The output voltage and current are all enhanced with the BT nanoparticles,which reached 200 V and 0.24μA in TENG with 40 wt% BT nanoparticles,respectively.The selected device exhibited the power of 0.16 mW and employed to demonstrate its ability to power wearable/portable electronics by lighting the LEDs.展开更多
基金Sponsored by Foundation of Department Education of Shaanxi Province of China(03JC31)Key Lab Foundationin Nanjing University of Science and Technology(51453010103SX0201).
文摘For measuring velocity and impacting position of single fragment of warhead,a non-contact measuring method is proposed,in which a six-light-screen array,a position indicator,a multi-channel chronograph and a computer are used.The principle of measurement is described.The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters.When the fragment flies through the light screen array,the time of passing through each of the screens is recorded by the multi-channel chronograph.According to the time data and the geometrical parameters of the array,the velocity vector and the location of the fragment can be calculated immediately.The presented method can be used to locate the fragment and to measure the real velocity on its flying direction.It can also be used to measure the velocity of a fragment swarm after the system is engineered further.
基金supported by the National Natural Science Foundation of China(Grant No.51972263).
文摘Recently,piezoelectric/triboelectric nanogenerators based on piezoelectric composite materials have been intensively studied to achieve high electrical output perfomiance.In this work,flexible BaTiO_(3)(BT)/PDMS nanocomposite films with various sizes and concentrations were fabricated and used as the nanogenerators.The influence of dielectric properties on the electrical output of nanogenerators was studied as well as the structure of the composites.The dielectric constant increased from 6.5 to 8 with the concentration of BT nanoparticles and decreased with the frequency from 10^(2) to 10^(6) Hz.Furthermore,the dielectric constant showed 11% decrease with the temperature range from 30 to 180℃.It was found that the concentration of BT nanoparticles has promoted the electrical output of nanogenerators.The output voltage and current are all enhanced with the BT nanoparticles,which reached 200 V and 0.24μA in TENG with 40 wt% BT nanoparticles,respectively.The selected device exhibited the power of 0.16 mW and employed to demonstrate its ability to power wearable/portable electronics by lighting the LEDs.
