Institute of Silicate Chemistry, Russian Academy of Science, Russian Federation
Time : 10:00 am-10:40 am
Professor Vladimir Ya. Shevchenko obtained pioneering results in the field of chemistry and technology of semiconductor compounds AIIBV, which laid the foundation for their introduction into new technology. Vladimir Ya. Shevchenko was the author of the discovery in USSR 196 of the structural dependence of semiconductor-metal transitions, which allowed predicting new semiconductor materials. He formulated and experimentally confirmed the fundamentals of the dissociative theory of fracture under extreme stresses, which made it possible to create products of special techniques widely used in practice. Currently Vladimir Ya. Shevchenko develops the physicochemical basis of the reaction-diffusion processes of morphogenesis, which determine the topochemical processes of the formation of triple periodic surfaces of minimal energy, which makes it possible to create "physical" cellular structures. Scientific interests: structural chemistry of nanostate, new biomaterials, nanoparticles, nanostructures and nanocomposites; physicochemistry and technology of technical ceramics.
Topology presents a unique opportunity to look into the physics of materials. Topological states provide a wide range of possibilities for discovering unknown phenomena of Nature. Examples of such states are, for example, the quantum Hall effect or insulators that can conduct electricity along a monatomic layer on their surface.
An interesting geometric relationship exists between the composition of atoms in crystalline materials and triple periodic minimal surface (TPMS). TPMS are observed in Nature in the form of interfaces, for example, in lipid binary layers and block copolymers. Nodal surfaces, the definition of a wave vector in the inverse space of an equipotential surface, soap films, elements of a smooth section of asymmetric domains in a given symmetry group are typical material objects that can be physically significant and which can help in visualizing of significant structures at a level higher than single atoms.
We firstly reported application of ceramic materials with triple periodic minimal surface (TPMS) topology as functional and structural elements. Such complicated structures may be produced only using additive technologies and may be applied for environment protection using catalysts for car exhausts and industrial gaseous and liquid pollutions due to intensification of mass and heat exchange. Also such structures may be used for efficient dissipation of mechanical energy in structures operating under conditions of extreme loads and dissipation of energy of acoustic waves. Details of structural, mechanical and functional properties of TPMS structures will be reported.
We firstly obtained a solid-phase material based on chromium carbide, which has a unique microstructure with the topology of triple periodic surfaces of minimal energy. For the first time, a deep connection between the reaction-diffusion Turing structures and triple periodic surfaces of minimal energy has been experimentally established. The possibility of formation as a result of reaction-diffusion interactions of a material with a microstructure having a topology similar to TPMS is shown. This result opens the perspective of obtaining new types of materials with a regulated microstructure.