A Physical Unclonable Function Based on Inter-Metal Layer Resistance Variations and an Evaluation of its Temperature and Voltage Stability

Keying material for encryption is stored as digital bistrings in non-volatile memory (NVM) on FPGAs and ASICs in current technologies. However, secrets stored this way are not secure against a determined adversary, who can use probing attacks to steal the secret. Physical Unclonable functions (PUFs) have emerged as an alternative. PUFs leverage random manufacturing variations as the source of entropy for generating random bitstrings, and incorporate an on-chip infrastructure for measuring and digitizing the corresponding variations in key electrical parameters, such as delay or voltage. PUFs are designed to reproduce a bitstring on demand and therefore eliminate the need for on-chip storage. In this dissertation, I propose a kind of PUF that measures resistance variations in inter-metal layers that define the power grid of the chip and evaluate its temperature and voltage stability. First, I introduce two implementations of a power grid-based PUF (PG-PUF). Then, I analyze the quality of bit strings generated without considering environmental variations from the PG-PUFs that leverage resistance variations in: 1) the power grid metal wires in 60 copies of a 90 nm chip and 2) in the power grid metal wires of 58 copies of a 65 nm chip. Next, I carry out a series of experiments in a set of 63 chips in IBM\u27s 90 nm technology at 9 TV corners, i.e., over all combination of 3 temperatures: -40oC, 25oC and 85oC and 3 voltages: nominal and +/-10% of the nominal supply voltage. The randomness, uniqueness and stability characteristics of bitstrings generated from PG-PUFs are evaluated. The stability of the PG-PUF and an on-chip voltage-to-digital (VDC) are also evaluated at 9 temperature-voltage corners. I introduce several techniques that have not been previously described, including a mechanism to eliminate voltage trends or \u27bias\u27 in the power grid voltage measurements, as well as a voltage threshold, Triple-Module-Redundancy (TMR) and majority voting scheme to identify and exclude unstable bits

Análisis de la estabilidad transitoria en sistemas eléctricos de potencia por el método de Runge-Kutta

This document presents a brief introduction and development of a numerical integration method known as Runge-Kutta, to study the behavior in the transient state of electric power systems, taking into consideration that there are multiple methods for the resolution of this issue. However, the advantages of using the mentioned method have been considered: high convergence speed compared to methods such as Euler's or the modified Euler. Emphasizing their characteristics and low error rate, they allow us to find a viable solution to the problems inherent in the behavior of electrical power systems. In addition, it should be noted that the nature of this article lies in the classic modeling of a generator, this in order to give way to the analysis to be carried out, taking into account the key components in the case to be studied, and considering the effects that they occur when this modeling allows the method to act to know a behavior in relation to the types of failure that may occur, such as line outputs, load problems, harmful indices within the operating parameters, generation problems (linked to it shifts from the angles of the motors and the correction times to return to a stable state) and components related to the concept of the infinite bar.Este documento presenta una breve introducción y desarrollo de un método de integración numérica conocido como Runge-Kutta, con el fin de estudiar el comportamiento en el estado transitorio de los sistemas de energía eléctrica, teniendo en cuenta que existen múltiples métodos para la resolución de este problema. Sin embargo, se han considerado las ventajas de usar el método mencionado: alta velocidad de convergencia en comparación con métodos como Euler o el Euler modificado. Al enfatizar sus características y su baja tasa de error, nos permiten encontrar una solución viable a los problemas inherentes al comportamiento de los sistemas de energía eléctrica. Además, debe tenerse en cuenta que la naturaleza de este artículo radica en el modelado clásico de un generador, esto para dar paso al análisis que se llevará a cabo, teniendo en cuenta los componentes clave en el caso a estudiar, y considerando los efectos que ocurren cuando este modelado permite que el método actúe para conocer un comportamiento en relación con los tipos de fallas que pueden ocurrir, como salidas de línea, problemas de carga, índices dañinos dentro de los parámetros operativos, problemas de generación (vinculados a él cambios desde los ángulos de los motores y los tiempos de corrección para volver a un estado estable) y componentes relacionados con el concepto de la barra infinita

Strong Neel ordering and luminescence correlation in a two-dimensional antiferromagnet

Magneto-optical effect has been widely used in light modulation, optical sensing and information storage. Recently discovered two-dimensional (2D) van der Waals layered magnets are considered as promising platforms for investigating novel magneto-optical phenomena and devices, due to the long-range magnetic ordering down to atomically-thin thickness, rich species and tunable properties. However, majority 2D antiferromagnets suffer from low luminescence efficiency which hinders their magneto-optical investigations and applications. Here, we uncover strong light-magnetic ordering interactions in 2D antiferromagnetic MnPS3 utilizing a newly-emerged near-infrared photoluminescence (PL) mode far below its intrinsic bandgap. This ingap PL mode shows strong correlation with the Neel ordering and persists down to monolayer thickness. Combining the DFT, STEM and XPS, we illustrate the origin of the PL mode and its correlation with Neel ordering, which can be attributed to the oxygen ion-mediated states. Moreover, the PL strength can be further tuned and enhanced using ultraviolet-ozone treatment. Our studies offer an effective approach to investigate light-magnetic ordering interactions in 2D antiferromagnetic semiconductors

2023 roadmap for potassium-ion batteries

The heavy reliance of lithium-ion batteries (LIBs) has caused rising concerns on the sustainability of lithium and transition metal and the ethic issue around mining practice. Developing alternative energy storage technologies beyond lithium has become a prominent slice of global energy research portfolio. The alternative technologies play a vital role in shaping the future landscape of energy storage, from electrified mobility to the efficient utilization of renewable energies and further to large-scale stationary energy storage. Potassium-ion batteries (PIBs) are a promising alternative given its chemical and economic benefits, making a strong competitor to LIBs and sodium-ion batteries for different applications. However, many are unknown regarding potassium storage processes in materials and how it differs from lithium and sodium and understanding of solid–liquid interfacial chemistry is massively insufficient in PIBs. Therefore, there remain outstanding issues to advance the commercial prospects of the PIB technology. This Roadmap highlights the up-to-date scientific and technological advances and the insights into solving challenging issues to accelerate the development of PIBs. We hope this Roadmap aids the wider PIB research community and provides a cross-referencing to other beyond lithium energy storage technologies in the fast-pacing research landscape

3d Momentum Imaging Spectroscopy Probing Of Strong-Field Molecular And Surface Dynamics

Electron-ion coincidence measurements in combination with 3-dimensional (3D) momentum imaging can provide comprehensive 3D-momentum information to unravel multichannel photoionization/dissociation processes, and thus is an effective tool to investigate atomic/molecular dynamics. A camera-based 3D coincidence momentum imaging system and the velocity mapping imaging (VMI) based machine were introduced in Chapter 2. Studies of strong field dissociative single and double ionization of relatively large molecules camphor and 2-phenylethyl-N, N-dimethylamine (PENNA) were carried out and illustrated in Chapter 3. We demonstrated the main products of double ionization of PENNA were singlet diradicals. In Chapter 4, a novel angle resolved-photoemission spectroscopy based on VMI apparatus was demonstrated. We employed this method to study multiphoton photoemission in thin metal films (Al and Cu), and hot carrier decay dynamics in graphene, in which unprecedented long hot carrier decay dynamics were observed (\u3e 1 ns)

30th International Conference on Condition Monitoring and Diagnostic Engineering Management (COMADEM 2017)

Proceedings of COMADEM 201

Impact of Discharge Duration on Lean Combustion in Spark Ignition Engines

Fuel-lean combustion in spark ignition engines is a promising strategy to improve engine efficiency. However, a fuel lean cylinder charge tends to lower the burning velocity because of the lowered chemical reactivity of the mixture, unless the flame propagation is accelerated by introducing an intensified flow field in the combustion chamber. Nevertheless, the literature reveals that the lean burn strategy with intensified flow fields can impose severe challenges on the ignition and flame development processes both in present and upcoming production engines. To address these issues and to better secure the flame kernel at the initial stage of combustion, various ignition strategies have been proposed with the aim of developing higher discharge current and longer discharge duration in the ignition processes, compared to those encountered with conventional spark ignition techniques. Moreover, while both current amplitude and duration of the plasma channel are fundamental to the flame kernel formation and development, their roles have not been fully clarified, let alone adequately quantified, in respect to the extensive variations in pressure, temperature, flow status, and mixture strength. Consequently, in this study, the impacts of discharge current amplitude and duration on the flame kernel initiation were investigated empirically using a constant volume combustion chamber and a single-cylinder research engine platform. The constant volume combustion chamber system was constructed so that a gas mixture with independently controlled pressure, composition, and flow intensity could be supplied. High-speed imaging was used to enable spatial and temporal characterizations of the flame kernel initiation process. Turbulence was generated inside the combustion chamber by a jet flow setup. A field programmable gate array (FPGA) controller was used to synchronize the controls of the sparking events, jet flow, and high-speed imaging. To achieve independent control of the discharge current amplitude and duration, the discharge current profile was modulated to form a quasi-rectangular shape by using a variety of hardware configurations and event controls. Ignition studies with various discharge current amplitudes and durations were conducted under both quiescent and flow conditions. Combustion test results showed that both discharge current amplitude and discharge duration had minimal impact on the ignition process under quiescent condition. However, under flow conditions, a longer discharge duration contributed to tailing flame kernels near the spark gap, and a higher discharge current amplitude contributed to larger flame kernels. Based on the experimental results and analysis, a correlation between the discharge current profiles and the flame kernel development was established with ultra-lean mixtures under intensified flow conditions. Additionally, the operational principles of the single-coil repetitive discharge and dual-coil offset discharge strategies were explored and explained. The necessary control algorithms for the repetitive and offset discharge strategies were established by analyzing the empirically acquired electrical waveforms of the discharge events. Finally, a preliminary investigation of the impact of discharge duration on the ignition stability was conducted using a single-cylinder research engine fitted with precise coolant conditioning, flexible air and fuel management, and comprehensive measurement and data acquisition. The experimental results indicated that a longer discharge duration contributed to improved combustion stability. However, ignition delay and combustion duration were unaffected by the prolonged discharge duration

Multilayer Thin Films

This book, "Multilayer Thin Films-Versatile Applications for Materials Engineering", includes thirteen chapters related to the preparations, characterizations, and applications in the modern research of materials engineering. The evaluation of nanomaterials in the form of different shapes, sizes, and volumes needed for utilization in different kinds of gadgets and devices. Since the recently developed two-dimensional carbon materials are proving to be immensely important for new configurations in the miniature scale in the modern technology, it is imperative to innovate various atomic and molecular arrangements for the modifications of structural properties. Of late, graphene and graphene-related derivatives have been proven as the most versatile two-dimensional nanomaterials with superb mechanical, electrical, electronic, optical, and magnetic properties. To understand the in-depth technology, an effort has been made to explain the basics of nano dimensional materials. The importance of nano particles in various aspects of nano technology is clearly indicated. There is more than one chapter describing the use of nanomaterials as sensors. In this volume, an effort has been made to clarify the use of such materials from non-conductor to highly conducting species. It is expected that this book will be useful to the postgraduate and research students as this is a multidisciplinary subject