Investigation on mechanical properties regulation of rock-like specimens based on 3D printing and similarity quantification

3D printing is widely adopted to quickly produce rock mass models with complex structures in batches,improving the consistency and repeatability of physical modeling.It is necessary to regulate the mechanical properties of 3D-printed specimens to make them proportionally similar to natural rocks.This study investigates mechanical properties of 3D-printed rock analogues prepared by furan resin-bonded silica sand particles.The mechanical property regulation of 3D-printed specimens is realized through quantifying its similarity to sandstone,so that analogous deformation characteristics and failure mode are acquired.Considering similarity conversion,uniaxial compressive strength,cohesion and stress–strain relationship curve of 3D-printed specimen are similar to those of sandstone.In the study ranges,the strength of 3D-printed specimen is positively correlated with the additive content,negatively correlated with the sand particle size,and first increases then decreases with the increase of curing temperature.The regulation scheme with optimal similarity quantification index,that is the sand type of 70/140,additive content of 2.5‰and curing temperature of 81.6℃,is determined for preparing 3D-printed sandstone analogues and models.The effectiveness of mechanical property regulation is proved through uniaxial compression contrast tests.This study provides a reference for preparing rock-like specimens and engineering models using 3D printing technology.

Analysis of finite-time regulation property of biomolecular PI controller

In practical applications of dynamic DNA nanotechnology,a biomolecular controller is required for maintaining the operation of the molecular actuator at a desired condition based on the information from molecular sensors.By making use of the DNA strand displacement mechanism as a"programming language"in the controller design,a biomolecular PI controller has been proposed.However,this PI control system has been verified only at the simulation level,and a theoretical regulation analysis is still required.Accordingly,in this study,we perform a rigorous regulation analysis of the biomolecular PI control system.Specifically,we theoretically prove that the output signal approaches the target level at a quasi-steady state.To this end,we apply the concept of finite-time regulation property to the biomolecular PI control system.

Regulation of neuroinflammatory properties of glial cells by T cell effector molecules

Multiple sclerosis （MS） is a chronic inflammatory and neurodegenerative disorder that is thought to be mediated by autoreactive T lymphocytes that find their way into the central nervous system （CNS）. The pathological mechanism of MS is still being elucidated but it involves complex interactions between infiltrating immune cells and resi- dent glial cells within the CNS that culminate into strong neuroinflammation and axonal damage.