11 research outputs found

    A two-step 5b logarithmic ADC with minimum step-size of 0.1% full-scale for MLC phase-change memory readout

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    High-Density Solid-State Memory Devices and Technologies

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    This Special Issue aims to examine high-density solid-state memory devices and technologies from various standpoints in an attempt to foster their continuous success in the future. Considering that broadening of the range of applications will likely offer different types of solid-state memories their chance in the spotlight, the Special Issue is not focused on a specific storage solution but rather embraces all the most relevant solid-state memory devices and technologies currently on stage. Even the subjects dealt with in this Special Issue are widespread, ranging from process and design issues/innovations to the experimental and theoretical analysis of the operation and from the performance and reliability of memory devices and arrays to the exploitation of solid-state memories to pursue new computing paradigms

    Development and validation of the thermal diagnostics instrumentation in lisa pathfinder

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    This thesis focuses on the issues related to the thermal diagnostics aboard the space mission LISA Pathfinder (LPF). LPF is a technological mission devoted to put to test critical subsystems for the LISA mission. LISA will be the first space born gravitational wave (GW) observatory with the main objective of detecting GWs. GWs are ripples of the space-time geometry caused by acceleration of masses in an asymmetric way. Their detection requires put test masses (TMs) in an almost perfect inertial frame (or free fall).Non-inertial forces perturbing the TMs must be less than 6 fN/sqrt(Hz) in the frequency range of 0.1 mHz to 0.1 Hz and the noise in the measurement between the TMs (separated by 5 Gm) must be of 40 pm/sqrt(Hz) in the same band. To reduce the risks of a direct launch of LISA, ESA has decided to first launch LPF to put all the LISA technologies to test.The payload of LPF, the LISA Technology Package (LTP), contains two TMs placed in two cylinders inside a single spacecraft (SC) and an interferometric system that measures the relative distance between them. The SC isolates the TMs from the external disturbances but internal stray forces will still perturb the TMs. Their levels must be bounded not to challenge the free fall accuracy. One of these disturbances is temperature fluctuations and the aspects related to their measurement are the leitmotif of this thesis.In chapter 1 we have presented how temperature fluctuations couple into the key subsystems of the LTP to degrade their performance. The foreseen effects are radiation pressure, radiometer effect, temperature coefficient of optical components, etc. Onground estimations conclude that the temperature stability in the LTP must be less than 100 microK/sqrt(Hz) in the frequency range of 1 mHz to 30 mHz (LTP band). Since temperature fluctuations are an important issue in LPF and in LISA, a thermal diagnostic subsystem is needed aboard both missions.The task of the thermal diagnostics in the LTP is twofold: on the one hand, temperature fluctuations in different subsystems must be measured with noise levels of 10 microK/sqrt(Hz) in the LTP band. On the other hand, a set of heaters will generate heat pulses that in conjunction with temperature measurements will be used to estimate the actual coupling between temperature and systems performance. These actions will provide information on the behaviour of the system and will permit to identify the fraction of noise in the system coming from temperature issues. The main function of LPF, as precursor mission of LISA, is the understanding of all the noise sources in the system. This will provide clues to the final leap from LPF sensitivity to LISA one.The main investigations carried out during this thesis can be split into three main categories: (i) the design and validation of the LTP temperature measurement subsystem (TMS); (ii) the extension of the system to the LISA requirements; and (iii) the analysis of the in-flight thermal experiments in the LTP. The thesis is organised as follows: in chapter 2 we describe the designed electronics and the temperature sensors chosen. Aspects related to the coupling of the TMS with other subsystems nearby are discussed in chapter 3. Chapter 4 focuses on the design of the testbed needed for the validation of the TMS. Two different testbeds are described: one for the LTP measurement bandwidth (MBW) and another one for the LISA MBW, 0.1 mHz. In chapter 5 we present the results of the test campaigns: the prototype, the engineering model and the flight model systems were put to test. The results of the investigations in the LISA band are also shown. Chapter 6 contains investigations in view of LISA requirements to reduce excess noise at very low frequency and to reduce the floor noise of the measurement. Chapter 7 focuses on the thermal experiment on-board LPF: a set of thermal excitations are proposed to extract information of the thermal behaviour of the key subsystems of the LTP

    Low Power Memory/Memristor Devices and Systems

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    This reprint focusses on achieving low-power computation using memristive devices. The topic was designed as a convenient reference point: it contains a mix of techniques starting from the fundamental manufacturing of memristive devices all the way to applications such as physically unclonable functions, and also covers perspectives on, e.g., in-memory computing, which is inextricably linked with emerging memory devices such as memristors. Finally, the reprint contains a few articles representing how other communities (from typical CMOS design to photonics) are fighting on their own fronts in the quest towards low-power computation, as a comparison with the memristor literature. We hope that readers will enjoy discovering the articles within

    Connected Attribute Filtering Based on Contour Smoothness

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    High Voltage Power Supply Design Guide for Space

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    This book is written for newcomers to the topic of high voltage (HV) in space and is intended to replace an earlier (1970s) out-of-print document. It discusses the designs, problems, and their solutions for HV, mostly direct current, electric power, or bias supplies that are needed for space scientific instruments and devices, including stepping supplies. Output voltages up to 30kV are considered, but only very low output currents, on the order of microamperes. The book gives a brief review of the basic physics of electrical insulation and breakdown problems, especially in gases. It recites details about embedment and coating of the supplies with polymeric resins. Suggestions on HV circuit parts follow. Corona or partial discharge testing on the HV parts and assemblies is discussed both under AC and DC impressed test voltages. Electric field analysis by computer on an HV device is included in considerable detail. Finally, there are many examples given of HV power supplies, complete with some of the circuit diagrams and color photographs of the layouts

    Smart Sensors for Healthcare and Medical Applications

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    This book focuses on new sensing technologies, measurement techniques, and their applications in medicine and healthcare. Specifically, the book briefly describes the potential of smart sensors in the aforementioned applications, collecting 24 articles selected and published in the Special Issue “Smart Sensors for Healthcare and Medical Applications”. We proposed this topic, being aware of the pivotal role that smart sensors can play in the improvement of healthcare services in both acute and chronic conditions as well as in prevention for a healthy life and active aging. The articles selected in this book cover a variety of topics related to the design, validation, and application of smart sensors to healthcare
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