ISOCONCENTRATION DISTRIBUTIONS OF COMPONENTS IN TERNARY GAS MIXTURES IN THE PRESENCE OF SPECIAL DIFFUSION MIXING MODES

The features of the formation of convective flows arising in three-component gas mixtures in the presence of special diffusion mixing regimes are investigated. The time variation of the isoconcentration lines of the heavy component of the mixture and the average kinetic energy are consideredas characteristics of convective flows. A numerical model based on the splitting scheme in physical parameters is used to calculate the characteristics of convective flows arising in a vertical cylindrical channel. It is shown that nonmonotonic distributions of component concentrations and kinetic energy can occur in ternary gas mixtures, where special diffusion regimes are manifested. The time of stability loss of the mechanical equilibrium of the mixture and the time of developed convective flows are determined.

3D-Printed Concentration-Controlled Microfluidic Chip with Diffusion Mixing Pattern for the Synthesis of Alginate Drug Delivery Microgels

Alginate as a good drug delivery vehicle has excellent biocompatibility and biodegradability. In the ionic gelation process between alginate and Ca2+, the violent reaction is the absence of a well-controlled strategy in the synthesizing calcium alginate (CaA) microgels. In this study, a concentration-controlled microfluidic chip with central buffer flow was designed and 3D-printed to well-control the synthesis process of CaA microgels by the diffusion mixing pattern. The diffusion mixing pattern in the microfluidic chip can slow down the ionic gelation process in the central stream. The particle size can be influenced by channel length and flow rate ratio, which can be regulated to 448 nm in length and 235 nm in diameter. The delivery ratio of Doxorubicin (Dox) in CaA microgels are up to 90% based on the central stream strategy. CaA@Dox microgels with pH-dependent release property significantly enhances the cell killing rate against human breast cancer cells (MCF-7). The diffusion mixing pattern gives rise to well-controlled synthesis of CaA microgels, serving as a continuous and controllable production process for advanced drug delivery systems.

Elaborately programmed nanowires fabricated using a tapered push–pull nozzle system

Elaborately programmed silver nanowire arrays can be prepared using a tapered push–pull nozzle system (TPPNS), which is used to directly write micro-nano wires on a substrate via a two-reagent reaction in the diffusion mixing region.