Based on transformation acoustics, an arbitrary-shaped acoustic cloak capable of functioning as an information exchange-enabling internal cloak and a movement-allowing external cloak is presented....

Superhydrophobic and oleophobic surfaces have attracted increasing attention because of their self-cleaning properties. A composite coating composed of anodized titanium and sol-gel (TiAO/SG) was developed and has good superhydrophobic and oleophobic property. The anodized titanium coating was prepared on the titanium substrate and then a sol-gel layer was coated on the surface of the anodized titanium layer to obtain a composite coating with superhydrophobic and oleophobic properties. The adhesion weight of glycerol on the surface of the superhydrophobic titanium wire decreased to 4.8% of that of untreated titanium wire, which showed that the material had good oleophobic property. This new composite coating could achieve self-healing superhydrophobicity by releasing loaded perfluorodenytriethoxysilane to the surface of the coating. Given its superhydrophobicity, self-healing and wear resistance, the TiAO/SG coating was expected to achieve healable self-cleaning protection in titanium devices.

Here, simultaneous extraction and SERS detection of nicotine for rapid and reliable identification of nicotine release of snus products were performed based on nano-Au assembly hierarchy structure in the capillary.

This study proposes a method to drive a solid by liquid–solid coupling and designs and manufactures a surface acoustic wave actuator to drive a wetted solid ball. The solid ball moves under surface acoustic wave microfluidic acoustic streaming. By theoretical analysis and experimental testing, the driving model is systematically examined in terms of the influence of the device frequency, input power, droplet viscosity, and other parameters on the movement of the ball. The speed at the mark end of the ball under 4.17 W of input power and driving at 60-MHz frequency in pure water reaches 0.175 m/s. Compared with the driving method of a surface acoustic wave linear motor, this wetted solid-driven method easily ensures that the solid ball drives to reach the same order of speed, avoiding numerous problems present in the existing surface acoustic wave linear motors. The proposed method provides important guidance and is of practical significance for the application of surface acoustic wave technology in micromotors and micromanipulation.

Numerous efficient catalysts have been introduced towards hydrogen evolution to produce H ₂ via water electrolysis. Besides developing highly active catalysts, considerable efforts should be focused on the reaction condition to accelerate electrochemical reactions. Increasing the operating temperature enhances the performances. Here, we demonstrate that a combination of a mature electro-thermal system with the state-of-art water splitting cells can promote hydrogen production efficiency in acid water. In particular, the current density of carbon coated Ag wire increased 12 mA cm ⁻² at elevated temperatures in comparison with room temperature. This heat-induced current increase was six times of Ag wire without carbon coating. The hydrogen evolution improvement is attributed to a better heat distribution in the micro-region between carbon surface and electrolyte. Graphitized carbon in the carbon layer, offers electron transfer pathways, which is beneficial for hydrogen evolution reaction performance; amorphous carbon and layered structure locked electrolyte, stop acid-water flowing and preserves heat.

In this work, a general method is presented for the design of arbitrarily shaped 3D illusion devices with piecewise homogeneous parameters based on geometric divisions and linear coordinate transformations. Three illusion devices that can reshape the sizes or positions of the wrapped objects are demonstrated, namely, shrinking, amplifying, and shifting devices. The shrinking device can shrink a larger object into a smaller one with different material parameters, whereas the amplifying device can enlarge a smaller object into a larger one, and a shifting device can generate a new image with an identical size but located at a different position. In addition, based on the presented shrinking device, a perfect 3D invisibility cloak is achieved by shrinking the wrapped object to sufficiently small dimensions as compared to the operating frequency. An electromagnetic concentrator is also obtained by replacing the coated object of the amplifying device with a compression medium. The presented design approach can be easily extended to the design of other electromagnetic devices and even to other physical fields. It is believed that the presented piecewise homogeneous devices are more practicable in reality and can accelerate the potential applications of illusion devices in both military and commercial fields.