Quasi-Band-Limited Coronagraph for Extended Sources

We propose a class of graded coronagraphic “amplitude” image masks for a high throughput Lyot-type coronagraph that transmits light from an annular region around an extended source and suppresses light, with extremely high ratio, from elsewhere. The interior radius of the region is comparable with its exterior radius. The masks are designed using an idea inspired by approach due M. J. Kuchner and W. A. Traub (“band-limited” masks) and approach to optimal apodization by D. Slepian. One potential application of our masks is direct high-resolution imaging of exo-planets with the help of the Solar Gravitational Lens, where apparent radius of the “Einstein ring” image of a planet is of the order of an arc-second and is comparable with the apparent radius of the sun and solar corona.

Fault Isolation of Metal-Insulator-Metal (MiM) Capacitor Failures by Lock-in Thermography (LIT)

The paper demonstrates accurate fault isolation information of metal-insulator-metal (MiM) capacitor failures by lock-in thermograph (LIT). In this study, a phase image spot location at a lock-in frequency larger than 5 Hz gives more accurate defect localization than an LIT amplitude image or OBIRCH to determine the next FA steps.

Detecting the deformation of fast ice by InSAR technology with Sentinel-1A descending and ascending orbits data

Accurate mapping of fast ice deformation can effectively characterize the rheological behavior of fast ice and subsequently improve sea ice model. This study used the Sentinel-1A descending and ascending orbits data to detect the deformations of fast ice in the Baltic Sea. A method for automatically obtaining fast ice edge line by combining interferometric coherence image and SAR amplitude image was proposed. Then, the deformations of fast ice were detected from different incidence angles with the descending and ascending orbits data. The results showed that the deformations in radar line of sight obtained from the descending and ascending orbits data were 38cm and 37cm respectively within the fast ice region of 960km2 in the study area. The continuous strong southwest wind was the principal reason for the deformation, and the deformation direction was dominated by east to west. Moreover, the inner fast ice kept stable and its deformation was smaller due to the protection of outer consolidated ice. The experimental results in this paper showed that the deformation trend and characteristics of fast ice can be better understood by InSAR technology with multi-orbits SAR data.

Enhanced phase and amplitude image contrasts of polymers in bimodal atomic force microscopy

Higher second free amplitudes beyond the commonly used values show remarkable phase and amplitude contrasts.