The nanocrystalline and amorphous Mg2Ni-type alloys with a chemical composition of （Mg24Ni10Cu2）100-xNdx （x=0, 5, 10, 15, 20） were fabricated by melt spinning technology. The effects of spinning rate on the struct...The nanocrystalline and amorphous Mg2Ni-type alloys with a chemical composition of （Mg24Ni10Cu2）100-xNdx （x=0, 5, 10, 15, 20） were fabricated by melt spinning technology. The effects of spinning rate on the structure and electrochemical hydrogen storage performance of the alloys were investigated. The as-spun Nd-free alloy displays an entire nanocrystalline structure, whereas the as-spun Nd-added alloys hold a nanocrystalline and amorphous structure, suggesting that the addition of Nd facilitates the glass forming of the Mg2Ni-type alloys. Increasing the spinning rate from 0 to 40 m/s gives rise to the discharge capacity growing from 42.5 to 100.6 mA·h/g for the x=0 alloy and from 86.4 to 452.8 mA·h/g for the x=10 alloy. And the cycle stability （S20） rises from 40.2%to 41.1%for the x=0 alloy and from 53.2%to 89.7%for the x=10 alloy, respectively.展开更多
The wave iterative method is a numerical method used in the electromagnetic modeling of high frequency electronic circuits. The object of the authors＇ study is to improve the convergence speed of this method by addin...The wave iterative method is a numerical method used in the electromagnetic modeling of high frequency electronic circuits. The object of the authors＇ study is to improve the convergence speed of this method by adding a new algorithm based on filtering techniques. This method requires a maximum number of iterations, noted Nmax, to achieve the convergence to the optimal value. This number wilt be reduced in order to reduce the computing time. The remaining iterations until Nmax will be calculated by the new algorithm which ensures a rapid convergence to the optimal result.展开更多
Expansive soils in Saudi Arabia have received wide attention in recent decades, following the rapid urbanization of rural and agricultural parts of the country. Tayma expansive shale inflicted serious damages to light...Expansive soils in Saudi Arabia have received wide attention in recent decades, following the rapid urbanization of rural and agricultural parts of the country. Tayma expansive shale inflicted serious damages to light structures, roads and boundary walls. This research is aimed at studying the engineering characteristics of the shale at this area including the basic geotechnical parameters as well as swelling behavior under oedometric loading conditions. The engineering properties were determined and compared to the local and international characterization charts. Mineralogy study using x-ray diffraction was conducted to investigate clay minerals present. The swell percent and the swelling pressure of the shale were investigated for samples prepared at different initial moisture contents and various dry densities. A close-up view of damages caused by the expansive shale in the town is highlighted and measures to reduce the risk of potential swelling distress for future constructions are presented.展开更多
In this work,a rotary pump based micromixer for on-chip rapid mixing and liquid transportation is demonstrated and characterized.Both pumping and mixing are realized using a microfluidic chip with a single structural ...In this work,a rotary pump based micromixer for on-chip rapid mixing and liquid transportation is demonstrated and characterized.Both pumping and mixing are realized using a microfluidic chip with a single structural polydimethylsiloxane layer and a portable electric control system.The rotary pump consists of an annular channel and is driven by a motor and magnets.The flow field caused by the peristaltic movement of the channel membrane of the rotary pump is simulated and analyzed.By statistically calculating and comparing the normalized standard deviations of the flow velocity components in a microchannel,it is revealed that up-and-down mixing is the fastest,followed by segment mixing and parallel mixing.Two mixing styles,segment mixing and parallel mixing,were experimentally demonstrated using the chip.The pump achieved 90% of the mixing index in 1 s for the segment mixing type.As for the parallel mixing type,the mixing index was up to 90% after 5 s,which is more than 100-fold improvement compared to conventional mixing by interfacial diffusion.The mixing speeds in both directions were improved prominently by increasing the rotational speed of the pump.展开更多
基金Projects (51161015,51371094) supported by the National Natural Science Foundation of ChinaProject (2011ZD10) supported by the Natural Science Foundation of Inner Mongolia,China
文摘The nanocrystalline and amorphous Mg2Ni-type alloys with a chemical composition of （Mg24Ni10Cu2）100-xNdx （x=0, 5, 10, 15, 20） were fabricated by melt spinning technology. The effects of spinning rate on the structure and electrochemical hydrogen storage performance of the alloys were investigated. The as-spun Nd-free alloy displays an entire nanocrystalline structure, whereas the as-spun Nd-added alloys hold a nanocrystalline and amorphous structure, suggesting that the addition of Nd facilitates the glass forming of the Mg2Ni-type alloys. Increasing the spinning rate from 0 to 40 m/s gives rise to the discharge capacity growing from 42.5 to 100.6 mA·h/g for the x=0 alloy and from 86.4 to 452.8 mA·h/g for the x=10 alloy. And the cycle stability （S20） rises from 40.2%to 41.1%for the x=0 alloy and from 53.2%to 89.7%for the x=10 alloy, respectively.
文摘The wave iterative method is a numerical method used in the electromagnetic modeling of high frequency electronic circuits. The object of the authors＇ study is to improve the convergence speed of this method by adding a new algorithm based on filtering techniques. This method requires a maximum number of iterations, noted Nmax, to achieve the convergence to the optimal value. This number wilt be reduced in order to reduce the computing time. The remaining iterations until Nmax will be calculated by the new algorithm which ensures a rapid convergence to the optimal result.
文摘Expansive soils in Saudi Arabia have received wide attention in recent decades, following the rapid urbanization of rural and agricultural parts of the country. Tayma expansive shale inflicted serious damages to light structures, roads and boundary walls. This research is aimed at studying the engineering characteristics of the shale at this area including the basic geotechnical parameters as well as swelling behavior under oedometric loading conditions. The engineering properties were determined and compared to the local and international characterization charts. Mineralogy study using x-ray diffraction was conducted to investigate clay minerals present. The swell percent and the swelling pressure of the shale were investigated for samples prepared at different initial moisture contents and various dry densities. A close-up view of damages caused by the expansive shale in the town is highlighted and measures to reduce the risk of potential swelling distress for future constructions are presented.
基金supported by the Major State Basic Research Development Program of China ((Grant No. 2007CB310504)the National Natural Science Foundation of China (Grant No. 50730009)
文摘In this work,a rotary pump based micromixer for on-chip rapid mixing and liquid transportation is demonstrated and characterized.Both pumping and mixing are realized using a microfluidic chip with a single structural polydimethylsiloxane layer and a portable electric control system.The rotary pump consists of an annular channel and is driven by a motor and magnets.The flow field caused by the peristaltic movement of the channel membrane of the rotary pump is simulated and analyzed.By statistically calculating and comparing the normalized standard deviations of the flow velocity components in a microchannel,it is revealed that up-and-down mixing is the fastest,followed by segment mixing and parallel mixing.Two mixing styles,segment mixing and parallel mixing,were experimentally demonstrated using the chip.The pump achieved 90% of the mixing index in 1 s for the segment mixing type.As for the parallel mixing type,the mixing index was up to 90% after 5 s,which is more than 100-fold improvement compared to conventional mixing by interfacial diffusion.The mixing speeds in both directions were improved prominently by increasing the rotational speed of the pump.
