Rechargeable aluminum batteries (Al batteries) can potentially be safer, cheaper, and deliver higher energy densities than those of commercial Li-ion batteries (LIBs). However, due to the very high charge density of Al cations and their strong interactions with the host lattice, very few cathode materials are known to be able to reversibly intercalate these ions. Herein, a rechargeable Al battery based on a two-dimensional (2D) vanadium carbide (VCT) MXene cathode is reported. The reversible intercalation of Al cations between the MXene layers is suggested to be the mechanism for charge storage. It was found that the electrochemical performance could be significantly improved by converting multilayered VCT particles to few-layer sheets. With specific capacities of more than 300 mAh g at high discharge rates and relatively high discharge potentials, VCT MXene electrodes show one of the best performances among the reported cathode materials for Al batteries. This study can lead to foundations for the development of high-capacity and high energy density rechargeable Al batteries by showcasing the potential of a large family of intercalation-type cathode materials based on MXenes.

The reverse engineering (RE) of electronic chips and systems can be used with honest and dishonest intentions. To inhibit RE for those with dishonest intentions (e.g., piracy and counterfeiting), it is important that the community is aware of the state-of-the-art capabilities available to attackers today. In this article, we will be presenting a survey of RE and anti-RE techniques on the chip, board, and system levels. We also highlight the current challenges and limitations of anti-RE and the research needed to overcome them. This survey should be of interest to both governmental and industrial bodies whose critical systems and intellectual property (IP) require protection from foreign enemies and counterfeiters who possess advanced RE capabilities.

No abstract

Bottom-up assembly of two-dimensional (2D) materials into macroscale morphologies with emergent properties requires control of the material surroundings, so that energetically favorable conditions direct the assembly process. MXenes, a class of recently developed 2D materials, have found new applications in areas such as electrochemical energy storage, nanoscale electronics, sensors, and biosensors. In this report, we present a lateral self-assembly method for wafer-scale deposition of a mosaic-type 2D MXene flake monolayers that spontaneously order at the interface between two immiscible solvents. Facile transfer of this monolayer onto a flat substrate (Si, glass) results in high-coverage (>90%) monolayer films with uniform thickness, homogeneous optical properties, and good electrical conductivity. Multiscale characterization of the resulting films reveals the mosaic structure and sheds light on the electronic properties of the films, which exhibit good conductivity over cm-scale areas.

Abstract

The smallest NPs, 10-nm MENs, were cleared relatively rapidly and uniformly across the organs, while the clearance of the larger NPs, 100- and 600-nm MENs, was highly nonlinear with time and nonuniform across the organs.

THz radiation is capable of penetrating most of nonmetallic materials and allows THz spectroscopy to be used to image the interior structures and constituent materials of wide variety of objects including Integrated circuits (ICs). The fact that many materials in THz spectral region have unique spectral fingerprints provides an authentication platform to distinguish between authentic and counterfeit electronic components. Counterfeit and authentic ICs are investigated using a high-speed terahertz spectrometer with laser pulse duration of 90 fs and repetition rate of 250 MHz with spectral range up to 3 THz. Time delays, refractive indices and absorption characteristics are extracted to distinguish between authentic and counterfeit parts. Spot measurements are used to develop THz imaging techniques. In this work it was observed that the packaging of counterfeit ICs, compared to their authentic counterparts, are not made from homogeneous materials. Moreover, THz techniques were used to observe different layers of the electronic components to inspect die and lead geometries. Considerable differences between the geometries of the dies/leads of the counterfeit ICs and their authentic counterparts were observed. Observing the different layers made it possible to distinguish blacktopped counterfeit ICs precisely. According to the best knowledge of authors the reported THz inspection techniques in this paper are reported for the first time for authentication of electronic components.Wide varieties of techniques such as X-ray tomography, scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and optical inspections using a high resolution microscope have also been being employed for detection of counterfeit ICs. In this paper, the achieved data from THz material inspections/ THz imaging are compared to the obtained results from other techniques to show excellent correlation. Compared to other techniques, THz inspection techniques have the privilege to be nondestructive, nonhazardous, less human dependent and fast.

Reverse engineering of electronics systems is performed for various reasons ranging from honest ones such as failure analysis, fault isolation, trustworthiness verification, obsolescence management, etc. to dishonest ones such as cloning, counterfeiting, identification of vulnerabilities, development of attacks, etc. Regardless of the goal, it is imperative that the research community understands the requirements, complexities, and limitations of reverse engineering. Until recently, the reverse engineering was considered as destructive, time consuming, and prohibitively expensive, thereby restricting its application to a few remote cases. However, the advents of advanced characterization and imaging tools and software have counteracted this point of view. In this paper, we show how X-ray micro-tomography imaging can be combined with advanced 3D image processing and analysis to facilitate the automation of reverse engineering, and thereby lowering the associated time and cost. In this paper, we demonstrate our proposed process on two different printed circuit boards (PCBs). The first PCB is a four-layer custom designed board while the latter is a more complex commercial system. Lessons learned from this effort can be used to both develop advanced countermeasures and establish a more efficient workflow for instances where reverse engineering is deemed necessary. Keywords: Printed circuit boards, non-destructive imaging, X-ray tomography, reverse engineering.