This article presents a multiscale study on adhesive interactions between graphene and its substrates. First, van der Waals (vdW) interactions between graphene and a SiO2 substrate are studied by fi rst-principle density functional theory (DFT) calculations with dispersion corrections. It is found that the interaction strength is strongly infl uenced by changes of the SiO2 surface structures du...

Recent methods have revealed that cells on planar substrates exert both shear (in-plane) and normal (out-of-plane) tractions against the extracellular matrix (ECM). However, the location and origin of the normal tractions with respect to the adhesive and cytoskeletal elements of cells have not been elucidated. We developed a high-spatiotemporal-resolution, multidimensional (2.5D) traction force...

This paper examines saturated control of a general class of uncertain nonlinear systems with timedelayed actuation and additive bounded disturbances. The bound on the control is known a priori and can be adjusted by changing the feedback gains. A Lyapunov-based stability analysis utilizing Lyapunov–Krasovskii (LK) functionals is provided to prove uniformly ultimately bounded tracking despite un...

The Hankel operator of the system with single control input delay is established by using state-space formulation in this paper. In general, this type of operator is not a compact one. Singular values of this type of operator are studied. Two examples are used to illustrate the computation of Hankel singular value by the theoretical method proposed in this paper.

This paper is concerned with the robustness of the predictor feedback control of linear systems with input delays. By applying certain equivalent transformations on the characteristic equation associated with the closed-loop system, we first transform the robustness problem of a predictor feedback control system into the stability problem of a neutral time-delay system containing an integral op...

The conversion from discrete-time to continuous-time models is sometimes quite troublesome. This paper answers related pending questions concerning z-domain poles at the origin, and relating them to s-domain models with time delay. Special attention is devoted to the tradeoff between fractional delay and direct feed-through. The paper places these questions into a general framework of model map...

S AbstractWe analyze the robust stability of Inverse LQ regulators for single-input linear systems with uncertain input delay. Unlike the usual LQ regulator, the Inverse LQ regulator has a gain tuning parameter that can be chosen freely to some extent without losing its LQ optimality. Utilizing this freedom we seek the range of tuning parameter that ensures the robust stability against the unce...

Only limited information is available concerning the effects of low-shear modeled microgravity (LSMMG) on cell function and morphology. We examined the behavior of Saccharomyces cerevisiae grown in a high-aspect-ratio vessel, which simulates the low-shear and microgravity conditions encountered in spaceflight. With the exception of a shortened lag phase (90 min less than controls; P < 0.05), ye...

Thrombus formation over a ruptured atherosclerotic plaque cap can occlude an artery with fatal consequences. We describe a computational model of platelet transport and binding to interpret rate-limiting steps seen in experimental thrombus formation over a collagen-coated stenosis. The model is used to compute shear rates in stenoses with growing boundaries. In the model, moving erythrocytes in...

In this work, the underlying micro-damage mechanisms of randomly oriented short fibre-reinforced composites were revealed based on real internal microstructural characteristics obtained by high-resolution (0.7 μm/pixel) synchrotron radiation X-ray computed tomography (SR-CT). The special 'pore dominant micro-damage processes' were directly observed through SR-CT three-dimensional reconstructed ...