Direct current (DC)-link voltage ripple analysis is essential for determining harmonic noise and for DC-link capacitor design and selection in single-phase pulse-width modulation (PWM) inverters. This paper provides an extensive theoretical analysis of DC-link voltage ripple for full-bridge (H-bridge) inverters, with simulation and experimental verifications, considering a DC source impedance (...

A recent theory is reviewed for the sample-to-sample fluctuations in the critical current of a Josephson junction consisting of a disordered point contact or microbridge. The theory is based on a relation between the supercurrent and the scattering matrix in the normal state. The root-mean-square amplitude rms Ic of the critical current Ic at zero temperature is given by rms Ic ≃ e∆0/h̄, up to a...

This study investigates the predictions of real contact area for perfectly elastic rough surfaces using a boundary element method (BEM). Sample surface measurements were used in BEM to predict as function load. The normalized by root-mean-square (RMS) slope evaluate if would collapse onto one master curve. If so, this confirm that areas manufactured, measured are directly proportional root mean...

PURPOSE To compare changes of anterior corneal aberration (Pentacam) and ocular aberration (aberrometer, LADARWave) after laser refractive surgery. METHODS Sixty-six eyes underwent laser refractive surgery and were retrospectively reviewed. Anterior corneal aberration and ocular aberration were measured by Pentacam and an aberrometer (LADARWave) respectively. Changes of root mean square (RMS)...

PURPOSE To compare corneal higher-order aberrations (HOAs) between normal and keratoconic eyes, and to investigate the association between elevation-based corneal topographic indices and corneal wavefront data in the latter group. METHODS In this cross-sectional comparative study, 77 normal right eyes of 77 control subjects and 66 eyes of 36 keratoconic patients were included. In each eye, el...

BACKGROUND Infants born preterm are at risk for developmental impairments related to postural control. OBJECTIVE The purpose of this study was to determine whether infants born preterm and infants born at full term differed in postural control at 1 to 3 weeks after term age. DESIGN This study included 17 infants born preterm (mean gestational age=31.9 weeks, range=25.0-34.6) and 15 infants ...

BACKGROUND Motion analysis of participants with different body shapes under diverse conditions can be problematic when vital markers are occluded. The markers located over the anterior superior iliac spines are commonly occluded in older patients and during analysis of activities with trunk and hip flexion which can prevent accurate calculation of lower limb joint kinematics. Options to modify ...

An Angular Spectrum Approach (ASA) is formulated and employed to simulate linear pulsed ultrasound fields for high bandwidth signals. A geometrically focused piston transducer is used as the acoustic source. Signals are cross-correlated to find the true sound speed during the measurement to make the simulated and measured pulses in phase for comparisons. The calculated sound speed in the measur...

Background & objectives Uncertainty often arises in differentiating seasonal variation from outbreaks of malaria. The present study was aimed to generalize the theoretical structure of sine curve for detecting an outbreak so that a tool for early warning of malaria may be developed. Methods A 'case/mean-ratio scale' system was devised for labelling the outbreak in respect of two diverse distr...