Biological application of Compressed Sensing Tomography in the Scanning Electron Microscope

The three-dimensional tomographic reconstruction of a biological sample, namely collagen fibrils in human dermal tissue, was obtained from a set of projection-images acquired in the Scanning Electron Microscope. A tailored strategy for the transmission imaging mode was implemented in the microscope and proved effective in acquiring the projections needed for the tomographic reconstruction. Suitable projection alignment and Compressed Sensing formulation were used to overcome the limitations arising from the experimental acquisition strategy and to improve the reconstruction of the sample. The undetermined problem of structure reconstruction from a set of projections, limited in number and angular range, was indeed supported by exploiting the sparsity of the object projected in the electron microscopy images. In particular, the proposed system was able to preserve the reconstruction accuracy even in presence of a significant reduction of experimental projections

Oxide Breakdown After RF Stress: Experimental Analysis and Effects on Power Amplifier Operation

The target in the design of CMOS radio-frequency (RF) transceivers for wireless application is the highest integration level, despite reliability issues of conventional submicron MOSFETs, due to high RF voltage and current peaks. In this scenario, this paper investigates gate-oxide breakdown under RF stress by using a class-E power amplifier (PA) for experiments. We showed that maximum RF voltage peaks for safe device operation are much larger than usual DC limits, and that the physical mechanism of oxide degradation is triggered by the rms value of oxide field, and not by its maximum, as generally believed. This finding has a strong impact on RF circuit designs, especially in MOSFET scaling perspectives. Finally, breakdown effects on PA operations are discussed

Electron tomography in the Scanning Electron Microscope for the investigation of biological and inorganic samples

This paper reports on the implementation of electron tomography in the Scanning Electron Microscope, describing its application in both physical and biological sciences. The experimental set up for tomography is described with emphasis on the scanning-transmission imaging modality, which allows one to record a series of projective images of a thin specimen. The computation of the three-dimensional arrangement of the constituents in graphene-ZnO nanorods and in collagen fibrils in dermal tissue is discussed. In addition, we show how the implementation of a compressed sensing approach can be useful to preserve nanometric resolution and overcome the limitations of the experimental strategy