Hu Luo

Robust platform for water harvesting and directional transport

Water harvesting is used for transforming moisture into available water resources in regions that suffer water scarcity. However, it remains a considerable challenge to design a system that functions to both collect water from the air and transport it to a certain region over a long distance. In this work, a new water harvesting platform for dropwise condensation and dropwise transportation is developed to realize both water collection and spontaneously directional transport over long-distance at low temperatures. The water harvesting platform was developed based on a biomimetic slippery liquid-infused porous surface (SLIPS) with micron-size steps and nano-sized holes through electrochemical etching, electrochemical anodizing, low surface energy modification and lubricant infusion. The anti-wetting, chemical resistance, condensation and anti-icing properties of the water harvesting platform at different pHs and temperatures were tested to show the stability of the system. The water harvesting platform exhibited excellent dropwise condensation capacity, and can directly and continuously capture moisture from the air in a low-temperature environment. Spontaneously directional transport of droplets was achieved on a choreographed wedged-platform driven by Laplace pressure, and the transport distance was unlimited due to the energy conversion from surface energy to kinetic energy induced by droplets coalescing in a repeated motion of droplet merging and chasing. This water harvesting platform shows great potential in applications for advanced transportation devices, multifunctional sensors, actuators, and is a promising potential solution to water scarcity.

Effects of Permanent Magnet Excitation on Material Removal Rate in Area Taking Magnetorhelogical Finishing

In this paper, a novel area taking MRF process using permanent magnet as excitation was proposed. Four types of permanent magnet configurations were considered. Polishing experiment was conducted. Effects of different permanent magnet configurations on material removal rate (MRR) were discussed.

Flexible cold plasma jet with controllable length and temperature for hydrophilic modification

With the advantages of high efficiency, simple equipment, good controllability, and the fact that they do no surface damage, atmospheric-pressure cold plasma jets are used to make solid surfaces hydrophilic. To transport the plasma jet effectively to the region to be modified and to reduce the amount of thermal damage to the surface during the modification, it is essential to control the transmission and temperature of the plasma jet from the distance. Flexible transmission and pre-cooling methods are proposed in this paper to solve this problem. An experimental device is constructed that mainly comprises the working gas, a power source, and a plasma generator. The test results show that (i) using a flexible catheter can extend the plasma transmission distance significantly and (ii) adjusting the driving voltage and gas flow allows the cold flexible plasma jet (FPJ) to reach several meters. Specially shaped jets such as plasma jet brushes can be generated conveniently based on the FPJ principle, thereby expanding the application range of the plasma. Pre-cooling the working gas with a vortex tube can lead to an FPJ with a simple structure without additional energy input and with a controllable temperature as low as −7 °C. The developed FPJ with a controllable length and temperature can be used to quickly modify various common solid surfaces, convert superhydrophobic surfaces into superhydrophilic surfaces, and preserve the microstructure of workpiece surfaces during modification.With the advantages of high efficiency, simple equipment, good controllability, and the fact that they do no surface damage, atmospheric-pressure cold plasma jets are used to make solid surfaces hydrophilic. To transport the plasma jet effectively to the region to be modified and to reduce the amount of thermal damage to the surface during the modification, it is essential to control the transmission and temperature of the plasma jet from the distance. Flexible transmission and pre-cooling methods are proposed in this paper to solve this problem. An experimental device is constructed that mainly comprises the working gas, a power source, and a plasma generator. The test results show that (i) using a flexible catheter can extend the plasma transmission distance significantly and (ii) adjusting the driving voltage and gas flow allows the cold flexible plasma jet (FPJ) to reach several meters. Specially shaped jets such as plasma jet brushes can be generated conveniently based on the FPJ principle, thereby e...

A Novel TEM Sample Preparation by Using Micro Magnetorheological Finishing

A novel TEM sample preparation method is proposed in this paper, which utilizes magnetorheological finishing to thin TEM sample. It can effectively reduce subsurface damage caused by mechanical lapping. A magnetorheological polishing tool is designed to meet TEM sample thinning requirements. Thinning testis conducted on Φ3mm single crystal silicon. Polished surface is observed by using transmission electron microscope, and high-resolution microscopy image of single crystal silicon can be achieved.