Establishment of Solid-Liquid-Solid Double-Layer Model of Silicon-Aluminum Phase in Mixed-Medium and Synergistic Stabilization Experimental Study

The issue of low resource utilization rate and high treatment cost in the disposal of construction waste and solid waste was a challenging problem. In order to seek a synergistic and efficient treatment method, based on the similarity of microstructural characteristics between clay, solid waste, and lithium slag particles, a dual-layer theory and model was used to conduct adaptive analysis at the electrochemical level, studying the solid-liquid-solid dual-layer theoretical model suitable for silicon-aluminum-phase materials. At the same time, the phenomenon of particle interface contact and the influence mechanism of ion adsorption on the surface of particles in the liquid phase were discussed, analyzing the ion selection mechanism for regulating the dual-layer of silicon-aluminum-phase materials and studying the method of clay-modified stabilization based on solid waste. Further laboratory tests and microscopic analyses were conducted to determine the engineering properties of the soil stabilized by the clay-solid waste synergistic stabilization and verified the effectiveness of the method. The research results showed that the trial soil stabilized by the theoretical model guidance was significantly stronger in unconfined compressive strength (1.44 MPa at 28 days) than the undisturbed clay (0.26 MPa at 28 days), and the scanning electron microscope (SEM) microscopic analysis results showed that the microscopic morphology of the modified stabilized soil specimen was tightly woven with a high-strength network-like structure. The research provided a theoretical basis and experimental reference for the synergistic treatment and resource utilization of waste soft soil and solid waste engineering problems.

Titanium-Based Metasurfaces for Optoelectronics

We report on the fabrication method that enables the development of transparent conductive metasurfaces capable of the resonant absorption of light in specific frequency bands. The approach is based on embedding linear sp-carbon chains and metallic nanoparticles in a porous matrix of titanium dioxide (TiO2). We develop a blading technique for the formation of a periodical grating of TiO2 microtubes at the macroscale. The method allowed us to maintain the periodicity of an array of microtubes with an accuracy of ±5%. Tuning the diameter of the tubes and the concentration of metallic nanoparticles, we achieved the regime of strong resonant absorption of the fabricated complex metasurface in the visible range. Computer simulations helped revealthe regime of TE/TM-polarized laser pumping that allowed for the most efficient transformation of light energy into electric current flow. In the studied structures, the sp-carbon clusters embedded inside transparent titanium dioxide tubes play the role of atomic wires. The interplay between efficient conductivity through carbon wires and the plasmon-enhanced absorption of light allows the design of photodiode structures based on periodical metasurfaces and characterized by highly selective optical sensitivity.

Electrophoresis and electric conduction in a salt-free suspension of charged particles

The electrophoresis and electric conduction of a suspension of charged spherical particles in a salt-free solution are analyzed by using a unit cell model. The linearized Poisson-Boltzmann equation (valid for the cases of relatively low surface charge density or high volume fraction of the particles) and Laplace equation are solved for the equilibrium electric potential profile and its perturbation caused by the imposed electric field, respectively, in the fluid containing the counterions only around the particle, and the ionic continuity equation and modified Stokes equations are solved for the electrochemical potential energy and fluid flow fields, respectively. Explicit analytical formulas for the electrophoretic mobility of the particles and effective electric conductivity of the suspension are obtained, and the particle interaction effects on these transport properties are significant and interesting. The scaled zeta potential, electrophoretic mobility, and effective electric conductivity increase monotonically with an increase in the scaled surface charge density of the particles and in general decrease with an increase in the particle volume fraction, keeping each other parameter unchanged. Under the Debye-Hückel approximation, the dependence of the electrophoretic mobility normalized with the surface charge density on the ratio of the particle radius to the Debye screening length and particle volume fraction in a salt-free suspension is same as that in a salt-containing suspension, but the variation of the effective electric conductivity with the particle volume fraction in a salt-free suspension is found to be quite different from that in a suspension containing added electrolyte.

Field-Induced Assembly of sp-sp2 Carbon Sponges

The formation of macroscale carbon structures characterised by an sp-sp2-hybridization is realised by self-assembly in colloidal solutions under an effect of laser irradiation and electromagnetic fields. The sponge-like morphology, sculptured with gold nanoparticles (NPs) was revealed by Scanning Electron Microscopy (SEM) imaging. Full structural and defect characterization of the self-assembled sponges was provided using the micro-Raman spectroscopic technique. The synthesized clusters manifest themselves in the presence of a strong spectral band in the visible range of the photoluminescence spectra that is quite unusual for ordered sp2-carbon systems.

Electrokinetic Flow of Salt-Free Solutions in a Fibrous Porous Medium

The electrokinetic flow of a salt-free solution in the fibrous porous medium constituted by an array of parallel charged circular cylinders subject to a pressure gradient and an electric field imposed in the axial direction is analytically studied via the use of a unit cell model. The Poisson-Boltzmann equation and modified Navier-Stokes equation applicable to a unit cell accommodating the salt-free solution around an individual cylinder are solved to determine the electric potential profile and fluid velocity distribution. Results of the electroosmotic velocity and effective electric conductivity in the fiber matrix are obtained as functions of the surface charge density of the dielectric cylinders and the porosity of the fiber matrix. The effects of the porosity or interactions among the cylinders on the electric potential distribution, electroosmotic velocity, and effective electric conductivity are significant and interesting under practical conditions. The apparent zeta potential, electroosmotic velocity, and effective electric conductivity increase monotonically with an increase in the surface charge density of the cylinders. When the porosity of the fiber matrix and surface charge density of the cylinders are high, the increases of the apparent zeta potential and electroosmotic velocity with the surface charge density are substantially suppressed due to the counterion condensation effect. However, this effect becomes weak when the porosity is low.

Influence of asymmetric depletion of solvents on the electric double layer of charged objects in binary polar solvent mixtures

The ratio of the dipole moment to the volume of solvent is the key factor for asymmetric depletion of solvents.