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Power converters are widely used over the world and are implemented in several electronic applications. This thesis was realised in partnership with CE+T POWER, one of the leaders on the power management market. The principal goal of this project was to revise their current DC/DC converter implemented inside one of their main products, the ``Sierra 10". To do so, the idea of replacing MOSFET by new GaN transistors was investigated.

First, the converter operations were studied and successfully checked on LTspice simulations. The wide bandgap semiconductors technology was summarised and it was shown that there were several advantages of using GaN instead of silicon transistors. GaN transistors are easy to use, allow new capabilities, are reliable, and will be at least as cost-effective as the silicon within few years.

Then, it was shown that the transistors of the converter were controllable by sensing the magnetising current. In practice, the drain current of the primary transistor is almost an image of the magnetising current (without considering the resonance part of the drain current). The drain current would be sensed. It was possible to fix the needed output power to compute the corresponding peak magnetising current values and switching frequency to impose. At first glance, there were several operating points for a given output power. However, it was shown, under assumptions, that an operating point which induces the lowest power losses inside the primary transistor existed. This could be translated into a simple optimisation problem. The mathematical programming results corresponded to the analytical results. The model suggested to decrease the switching frequency around 30 kHz for a peak magnetising current of 81 A. This operating point might not be the most practical one in terms of transformer sizing and cost. Supplementary manufacturing constraints could be added to the model to shift the minimum losses operating point.

The obtained results showed that a possible minimum losses operating point exists and could be tracked under a simple model of losses computation that could be sharpened in function of the technical constraints.

wide bandgap semiconductor --- GaN --- dc/dc converter --- power electronics --- power converter --- MOSFET --- Ingénierie, informatique & technologie > Ingénierie électrique & électronique

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This Special Issue will compile recent developments in the field of metal oxide thin film deposition. The articles presented in this Special Issue will cover various topics, ranging from, but not limited to, the optimization of deposition methods, thin film preparations, the functionalization of surfaces with targeted applications, nanosensors, catalysis, electronic devices, biocidal coating, and the synthesis of nanostructures via the accurate control of thin film deposition methods, among others. Topics are open to metal oxide thin film deposition and characterization for the development of applications.

Technology: general issues --- History of engineering & technology --- Materials science --- plasma electrolytic oxidation --- electrical characteristic --- anodizing --- SEM --- aluminum --- low-temperature fabrication --- ions adsorption --- IGZO TFTs --- device performance --- oxidation --- wide-bandgap semiconductor --- α-Ga2O3 --- mist chemical vapor deposition (mist-CVD) --- carrier gas --- transparent semiconductor --- cellulose --- tribological performance --- stability --- MAO (micro-arc oxidation) coating --- self-lubricating --- gadolinium cobaltites --- atomic layer deposition --- β-diketonates --- ozone --- preferential crystal growth orientation --- high-aspect-ratio substrate --- metal oxide thin films --- ALD --- crystallography --- epitaxy --- NiTiO3 --- tin oxide --- thin films --- atmospheric pressure chemical vapour deposition transport properties --- magnetoresistance --- impedance spectroscopy --- charge carrier mobility --- dynamic hot-probe measurements --- indium-tin oxide --- aluminum-zinc oxide --- magnetron co-sputtering --- bismuth ferrite --- La-doping --- piezoelectricity --- sol–gel --- n/a --- sol-gel

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Fuzzy Logic is a good model for the human ability to compute words. It is based on the theory of fuzzy set. A fuzzy set is different from a classical set because it breaks the Law of the Excluded Middle. In fact, an item may belong to a fuzzy set and its complement at the same time and with the same or different degree of membership. The degree of membership of an item in a fuzzy set can be any real number included between 0 and 1. This property enables us to deal with all those statements of which truths are a matter of degree. Fuzzy logic plays a relevant role in the field of Artificial Intelligence because it enables decision-making in complex situations, where there are many intertwined variables involved. Traditionally, fuzzy logic is implemented through software on a computer or, even better, through analog electronic circuits. Recently, the idea of using molecules and chemical reactions to process fuzzy logic has been promoted. In fact, the molecular word is fuzzy in its essence. The overlapping of quantum states, on the one hand, and the conformational heterogeneity of large molecules, on the other, enable context-specific functions to emerge in response to changing environmental conditions. Moreover, analog input–output relationships, involving not only electrical but also other physical and chemical variables can be exploited to build fuzzy logic systems. The development of “fuzzy chemical systems” is tracing a new path in the field of artificial intelligence. This new path shows that artificially intelligent systems can be implemented not only through software and electronic circuits but also through solutions of properly chosen chemical compounds. The design of chemical artificial intelligent systems and chemical robots promises to have a significant impact on science, medicine, economy, security, and wellbeing. Therefore, it is my great pleasure to announce a Special Issue of Molecules entitled “The Fuzziness in Molecular, Supramolecular, and Systems Chemistry.” All researchers who experience the Fuzziness of the molecular world or use Fuzzy logic to understand Chemical Complex Systems will be interested in this book.

Research & information: general --- Biology, life sciences --- fuzzy logic --- complexity --- chemical artificial intelligence --- human nervous system --- fuzzy proteins --- conformations --- photochromic compounds --- qubit --- protein dynamics --- conformational heterogeneity --- promiscuity --- fuzzy complexes --- higher-order structures --- protein evolution --- fuzzy set theory --- artificial intelligence --- GCN4 mimetic --- peptides–DNA --- E:Z photoisomerization --- conformational fuzziness --- photoelectrochemistry --- wide bandgap semiconductor --- artificial neuron --- in materio computing --- neuromorphic computing --- intrinsically disordered protein --- intrinsically disordered protein region --- liquid–liquid phase transition --- protein–protein interaction --- protein–nucleic acid interaction --- proteinaceous membrane-less organelle --- fuzzy complex. --- d-TST --- activation energy --- Transitivity plot --- solution kinetic --- Maxwell–Boltzmann path --- Euler’s formula for the exponential --- activation --- transitivity --- transport phenomena --- moonlighting proteins --- intrinsically disordered proteins --- metamorphic proteins --- morpheeins --- n/a --- peptides-DNA --- liquid-liquid phase transition --- protein-protein interaction --- protein-nucleic acid interaction --- Maxwell-Boltzmann path --- Euler's formula for the exponential

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Fuzzy Logic is a good model for the human ability to compute words. It is based on the theory of fuzzy set. A fuzzy set is different from a classical set because it breaks the Law of the Excluded Middle. In fact, an item may belong to a fuzzy set and its complement at the same time and with the same or different degree of membership. The degree of membership of an item in a fuzzy set can be any real number included between 0 and 1. This property enables us to deal with all those statements of which truths are a matter of degree. Fuzzy logic plays a relevant role in the field of Artificial Intelligence because it enables decision-making in complex situations, where there are many intertwined variables involved. Traditionally, fuzzy logic is implemented through software on a computer or, even better, through analog electronic circuits. Recently, the idea of using molecules and chemical reactions to process fuzzy logic has been promoted. In fact, the molecular word is fuzzy in its essence. The overlapping of quantum states, on the one hand, and the conformational heterogeneity of large molecules, on the other, enable context-specific functions to emerge in response to changing environmental conditions. Moreover, analog input–output relationships, involving not only electrical but also other physical and chemical variables can be exploited to build fuzzy logic systems. The development of “fuzzy chemical systems” is tracing a new path in the field of artificial intelligence. This new path shows that artificially intelligent systems can be implemented not only through software and electronic circuits but also through solutions of properly chosen chemical compounds. The design of chemical artificial intelligent systems and chemical robots promises to have a significant impact on science, medicine, economy, security, and wellbeing. Therefore, it is my great pleasure to announce a Special Issue of Molecules entitled “The Fuzziness in Molecular, Supramolecular, and Systems Chemistry.” All researchers who experience the Fuzziness of the molecular world or use Fuzzy logic to understand Chemical Complex Systems will be interested in this book.

fuzzy logic --- complexity --- chemical artificial intelligence --- human nervous system --- fuzzy proteins --- conformations --- photochromic compounds --- qubit --- protein dynamics --- conformational heterogeneity --- promiscuity --- fuzzy complexes --- higher-order structures --- protein evolution --- fuzzy set theory --- artificial intelligence --- GCN4 mimetic --- peptides–DNA --- E:Z photoisomerization --- conformational fuzziness --- photoelectrochemistry --- wide bandgap semiconductor --- artificial neuron --- in materio computing --- neuromorphic computing --- intrinsically disordered protein --- intrinsically disordered protein region --- liquid–liquid phase transition --- protein–protein interaction --- protein–nucleic acid interaction --- proteinaceous membrane-less organelle --- fuzzy complex. --- d-TST --- activation energy --- Transitivity plot --- solution kinetic --- Maxwell–Boltzmann path --- Euler’s formula for the exponential --- activation --- transitivity --- transport phenomena --- moonlighting proteins --- intrinsically disordered proteins --- metamorphic proteins --- morpheeins --- n/a --- peptides-DNA --- liquid-liquid phase transition --- protein-protein interaction --- protein-nucleic acid interaction --- Maxwell-Boltzmann path --- Euler's formula for the exponential

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Emerging wide bandgap (WBG) semiconductors hold the potential to advance the global industry in the same way that, more than 50 years ago, the invention of the silicon (Si) chip enabled the modern computer era. SiC- and GaN-based devices are starting to become more commercially available. Smaller, faster, and more efficient than their counterpart Si-based components, these WBG devices also offer greater expected reliability in tougher operating conditions. Furthermore, in this frame, a new class of microelectronic-grade semiconducting materials that have an even larger bandgap than the previously established wide bandgap semiconductors, such as GaN and SiC, have been created, and are thus referred to as “ultra-wide bandgap” materials. These materials, which include AlGaN, AlN, diamond, Ga2O3, and BN, offer theoretically superior properties, including a higher critical breakdown field, higher temperature operation, and potentially higher radiation tolerance. These attributes, in turn, make it possible to use revolutionary new devices for extreme environments, such as high-efficiency power transistors, because of the improved Baliga figure of merit, ultra-high voltage pulsed power switches, high-efficiency UV-LEDs, and electronics. This Special Issue aims to collect high quality research papers, short communications, and review articles that focus on wide bandgap device design, fabrication, and advanced characterization. The Special Issue will also publish selected papers from the 43rd Workshop on Compound Semiconductor Devices and Integrated Circuits, held in France (WOCSDICE 2019), which brings together scientists and engineers working in the area of III–V, and other compound semiconductor devices and integrated circuits.

Technology: general issues --- GaN --- high-electron-mobility transistor (HEMT) --- ultra-wide band gap --- GaN-based vertical-cavity surface-emitting laser (VCSEL) --- composition-graded AlxGa1−xN electron blocking layer (EBL) --- electron leakage --- GaN laser diode --- distributed feedback (DFB) --- surface gratings --- sidewall gratings --- AlGaN/GaN --- proton irradiation --- time-dependent dielectric breakdown (TDDB) --- reliability --- normally off --- power cycle test --- SiC micro-heater chip --- direct bonded copper (DBC) substrate --- Ag sinter paste --- wide band-gap (WBG) --- thermal resistance --- amorphous InGaZnO --- thin-film transistor --- nitrogen-doping --- buried-channel --- stability --- 4H-SiC --- turn-off loss --- ON-state voltage --- breakdown voltage (BV) --- IGBT --- wide-bandgap semiconductor --- high electron mobility transistors --- vertical gate structure --- normally-off operation --- gallium nitride --- asymmetric multiple quantum wells --- barrier thickness --- InGaN laser diodes --- optical absorption loss --- electron leakage current --- wide band gap semiconductors --- numerical simulation --- terahertz Gunn diode --- grooved-anode diode --- Gallium nitride (GaN) high-electron-mobility transistors (HEMTs) --- vertical breakdown voltage --- buffer trapping effect --- gallium nitride (GaN) --- power switching device --- active power filter (APF) --- power quality (PQ) --- metal-insulator-semiconductor high-electron-mobility transistor (MIS-HEMT) --- recessed gate --- double barrier --- high-electron-mobility transistors --- copper metallization --- millimeter wave --- wide bandgap semiconductors --- flexible devices --- silver nanoring --- silver nanowire --- polyol method --- cosolvent --- tungsten trioxide film --- spin coating --- optical band gap --- morphology --- electrochromism --- self-align --- hierarchical nanostructures --- ZnO nanorod/NiO nanosheet --- photon extraction efficiency --- photonic emitter --- wideband --- HEMT --- power amplifier --- jammer system --- GaN 5G --- high electron mobility transistors (HEMT) --- new radio --- RF front-end --- AESA radars --- transmittance --- distortions --- optimization --- GaN-on-GaN --- schottky barrier diodes --- high-energy α-particle detection --- low voltage --- thick depletion width detectors --- n/a