Marangoni-flow-assisted assembly of single-walled carbon nanotube films for human motion sensing

Single-walled carbon nanotubes(SWCNTs)present excellent electronic and mechanical properties desired in wearable and flexible devices.The preparation of SWCNT films is the first step for fabricating various devices.This work developed a scalable and feasible method to assemble SWCNT thin films on water surfaces based on Marangoni flow induced by surface tension gradient.The films possess a large area of 40 cm×30 cm(extensible),a tunable thickness of 15∼150 nm,a high transparency of up to 96%,and a decent conductivity.They are ready to be directly transferred to various substrates,including flexible ones.Flexible strain sensors were fabricated with the films on flexible substrates.These sensors worked with high sensitivity and repeatability.By realizing multi-functional human motion sensing,including responding to voices,monitoring artery pulses,and detecting knuckle and muscle actions,the assembled SWCNT films demonstrated the potential for application in smart devices.

Confined-solution process for high-quality CH3NH3PbBr3 single crystals with controllable morphologies

Solution processes have shown excellent potential for application to the growth of single-crystal materials. We have developed a confined-solution method for the preparation of single crystals with a controlled morphology. By confining the precursor solution within a micrometer-thick cavity and then controlling the saturation by adjusting the temperature gradient and fluid flow, high-quality CHBNH3PbBr3 single crystals with tunable morphologies could be obtained. The morphologies of the CH3NH3PbBr3 can be adjusted from sub-square centimeter-scale thin sheets that are square or rectangular, to one-dimensional wires with lengths in the order of centimeters, simply by changing the temperature. The thicknesses of the CH3NH3PbBr3 sheets could be adjusted from hundreds of nanometers to tens of microns. The CH3NHBPbBr3 sheets feature very clean surfaces with an atomic-scale roughness. This simple strategy provides a means of growing high-quality single crystals with clean surfaces, which realize high levels of performance when applied to devices.

Epitaxial growth of horizontally aligned single-crystal arrays of perovskite

Well-aligned single-crystal nanowire arrays of CH3NH3PbIs have shown potentials in laser sources and photovoltaic applications.Here we developed a solution based epitaxial method to grow CH3NH3PbI3nanowire arrays.By confining the precursor solution between a silicon wafer and ST-cut quartz,the evaporation rate of the solvent was slowed down which brings a more stable and controllable solution environment.Relying on the lattice match between CH3NH3PbI3 and ST-cut quartz,arrays of single-crystal nanowires of CH3NH3PbI3have been grown epitaxially.The densities and lengths of CH3NH3PbI3 nanowires can be tuned. The lengths of the resultant crystals range from several microns to over one millimeter.Such CH3NH3PbI3arrays with good alignment and crystallinity were then applied to fabricate photovoltaic devices with good performances.

Patterning catalyst via inkjet printing to grow single-walled carbon nanotubes

Controlled growth of patterned single-walled carbon nanotubes (SWNTs) is an important issue in many applications. Herein, we demonstrated a method to pattern catalyst via inkjet printing for the growth of SWNTs, using metal salt solutions as the inks and an ordinary office-use printer. We printed water solutions of cobalt acetate on hydrophilic Si substrates and grew high quality SWNT films. The composition of the precursor solutions and the hydrophilicity of the substrates were crucial factors to the patterning.

At the Nexus of New Challenges： China＇s Leadership Change and Cross-Strait Relations

China＇s 2012 leadership change revealed signs of factional divide at the top level. The elitist/princeling faction has outnumbered the populist faction. Princelings have better and stronger ties with the military, which tends to have a more hawkish view regarding any potential Taiwan independence. In Taiwan, changing social experiences have created a new Taiwan Residents identity, which is dif- ferent from that of the Chinese. People in Taiwan are increasingly thinking of themselves as Taiwan Residents instead of Chinese. On the mainland, Chinese popular nationalism has been on the rise, as anti-Taiwan independence remains one of the most nationalistic issues. When the forces of new identity and nationalism meet each other, a diverging path regarding the future of Taiwan is being created. Moreover, China＇s economic and military power continues to rise, giving China more confidence. I argue that the overall effect is that China＇s new leadership will increasingly have the capability to act tougher against any potential Taiwan Residents independence. The potential need to act tougher with Taiwan may be beyond the desire and control of Chinese elites due to the rise of popular nationalism in China and the leadership＇s need to maintain internal legitimacy and survival.