arXiv subjects

Jiarui Yang

Publications and source records attributed to Jiarui Yang.

38 records · Page 3Linked to original sources

arXiv2011

Self-retracting motion of graphite micro-flakes: superlubricity in micrometer scale

Through experimental study, we reveal superlubricity as the mechanism of self-retracting motion of micrometer sized graphite flakes on graphite platforms by correlating respectively the lock-up or self-retraction states with the commensurate or incommensurate contacts. We show that the scale-dependent loss of self-retractability is caused by generation of contact interfacial defects. A HOPG structure is also proposed to understand our experimental observations, particularly in term of the polycrystal structure. The realisation of the superlubricity in micrometer scale in our experiments will have impact in the design and fabrication of micro/nanoelectromechanical systems based on graphitic materials.

cond-mat.mes-hall↗

arXiv2010

Quantifying Uncertainties in Complex Systems

Uncertainties are abundant in complex systems. Mathematical models for these systems thus contain random effects or noises. The models are often in the form of stochastic differential equations, with some parameters to be determined by observations. The stochastic differential equations may be driven by Brownian motion, fractional Brownian motion or Lévy motion. After a brief overview of recent advances in estimating parameters in stochastic differential equations, various numerical algorithms for computing parameters are implemented. The numerical simulation results are shown to be consistent with theoretical analysis. Moreover, for fractional Brownian motion and $α-$stable Lévy motion, several algorithms are reviewed and implemented to numerically estimate the Hurst parameter $H$ and characteristic exponent $α$.

math.NA↗