Testing of ADC differential nonlinearity by the histogram method requires a signal generator with extremely low distortion and high stability. In this paper, the new type of stimulus signal is proposed, which simplifies the task. The testing signal has an exponential form and can be generated simply by discharging the capacitor across the resistance. The resulting digital samples from the outpu...

We consider the design and analysis of numerical methods for approximating positive solutions to nonlinear geometric elliptic partial differential equations containing critical exponents. This class of problems includes the Yamabe problem and the Einstein constraint equations, which simultaneously contain several challenging features: high spatial dimension n > 3, varying (potentially non-smoot...

AGNETIC resonance imaging (MRI) provides an excellent modality for distinguishing different tissues in the human body, which is essential for medical applications. When MRI is used for stereotactic treatment planning, its geometric accuracy is crucial. Previous studies have been conducted to correct the distortion caused by nonlinearity of the MRI scanner’s magnetic gradient fields by imaging a...

In this paper, quantitative understanding of a frequency-domain nonlinearity indicator is developed. The indicator is derived from an ensemble-averaged, frequency-domain version of the generalized Burgers equation, which can be rearranged in order to directly compare the effects of nonlinearity, absorption, and geometric spreading on the pressure spectrum level with frequency and distance. The ...

A geometrically exact formulation of cables suffering axis stretching and flexural curvature is presented. The dynamical formulation is based on nonlinearly viscoelastic constitutive laws for the tension and bending moment with the additional constitutive nonlinearity accounting for the nocompression condition. A continuation method, combined with a mixed finite-difference spatial discretizatio...

PURPOSE To propose a method for calibrating gradient systems and correcting gradient nonlinearities based on diffusion MRI measurements. METHODS The gradient scaling in x, y, and z were first offset by up to 5% from precalibrated values to simulate a poorly calibrated system. Diffusion MRI data were acquired in a phantom filled with cyclooctane, and corrections for gradient scaling errors and...

The nonlinear mechanical behavior of tissues that undergo large deformations, e.g. the breast, is characterized by hyperelastic parameters. These parameters take into account both types of nonlinearities: tissue intrinsic nonlinearity and geometric nonlinearity. Elastography technique capable of tissue hyperelastic parameter reconstruction has important clinical applications such as cancer diag...

Free vibration of an axially loaded silicon microbeam in MEMS under electrostatic actuation is studied on the basis a sinusoidal shear deformation theory. Based modified couple stress theory (MCST) and von Kármán geometric nonlinearity, nonlinear finite element formulation derived employed to construct discrete governing equations for microbeam. The deflection at given DC voltage firstly calcul...

Based on the nonlocal Timoshenko beam theory, the dynamic stability of functionally gradded (FG) nanoeams under axial load is studied in thermal environment, with considering surface effect. It is used power law distribution for FGM and the surface stress effects are considered based on Gurtin-Murdoch continuum theory. Using Von Karman geometric nonlinearity, governing equations are derived bas...

Nonlinear vibration of a fluid-filled single walled carbon nanotube (SWCNT) with simply supported ends is investigated in this paper based on Von-Karman’s geometric nonlinearity and the simplified Donnell’s shell theory. The effects of the small scales are considered by using the nonlocal theory and the Galerkin's procedure is used to discretize partial differential equations of the governing i...