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The analysis of bioelectrical signals continues to receive wide attention in research as well as commercially because novel signal processing techniques have helped to uncover valuable information for improved diagnosis and therapy. This book takes a unique problem-driven approach to biomedical signal processing by considering a wide range of problems in cardiac and neurological applications, the two \"heavyweight\" areas of biomedical signal processing. The interdisciplinary nature of the topic is reflected in how the text interweaves physiological issues with related methodological considerations. This book is suitable for a final year undergraduate or graduate course as well as for use as an authoritative reference for practicing engineers, physicians, and researchers.

Unparalleled in the breadth and depth of its coverage of all important aspects, this book systematically treats the electronic and magnetic properties of stoichiometric and non-stoichiometric cobaltites in both ordered and disordered phases.

\"This book reviews research on single-electron devices and circuits in silicon. These devices provide a means to control electronic charge at the one-electron level and are promising systems for the development of few-electron, nanoscale electronic circuits. The book considers the design, fabrication, and characterization of single-electron transistors, single-electron memories, few-electron transfer devices such as electron pumps and turnstiles, and single-electron logic devices. A review of the many different approaches used for the experimental realisation of these devices is provided and devices developed during the author's own research are used as detailed examples. An introduction to the physics of single-electron charging effects is included.\"--Jacket.

The addition of boron nitride nanosheets to polymer nanocomposites creates dielectric materials that operate at much higher working temperatures than previous polymer dielectrics, as well as being flexible, lightweight, photopatternable, scalable and robust, which now makes them more attractive for electronic device applications than ceramic dielectrics. Polymer nanocomposites as high-temperature dielectrics Dielectric materials for capacitative energy storage need to function in harsh conditions if they are to be used, for example, in electric vehicles or aerospace applications. Polymer dielectrics are lightweight and therefore are attractive from a power-to-weight point of view, but these materials have tended to breakdown at operating temperatures common in power inverters. Here Qing Wang and colleagues demonstrate that the addition of boron nitride nanosheets to polymer nanocomposites increases heat dissipation properties, resulting in dielectric materials that operate at much higher working temperatures than previously possible with polymer dielectrics. These new nanocomposites are flexible, lightweight, photopatternable, scalable and robust, making them potentially more attractive that conventional ceramic dielectrics for electronic device applications. Dielectric materials, which store energy electrostatically, are ubiquitous in advanced electronics and electric power systems 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 . Compared to their ceramic counterparts, polymer dielectrics have higher breakdown strengths and greater reliability 1 , 2 , 3 , 9 , are scalable, lightweight and can be shaped into intricate configurations, and are therefore an ideal choice for many power electronics, power conditioning, and pulsed power applications 1 , 9 , 10 . However, polymer dielectrics are limited to relatively low working temperatures, and thus fail to meet the rising demand for electricity under the extreme conditions present in applications such as hybrid and electric vehicles, aerospace power electronics, and underground oil and gas exploration 11 , 12 , 13 . Here we describe crosslinked polymer nanocomposites that contain boron nitride nanosheets, the dielectric properties of which are stable over a broad temperature and frequency range. The nanocomposites have outstanding high-voltage capacitive energy storage capabilities at record temperatures (a Weibull breakdown strength of 403 megavolts per metre and a discharged energy density of 1.8 joules per cubic centimetre at 250 degrees Celsius). Their electrical conduction is several orders of magnitude lower than that of existing polymers and their high operating temperatures are attributed to greatly improved thermal conductivity, owing to the presence of the boron nitride nanosheets, which improve heat dissipation compared to pristine polymers (which are inherently susceptible to thermal runaway). Moreover, the polymer nanocomposites are lightweight, photopatternable and mechanically flexible, and have been demonstrated to preserve excellent dielectric and capacitive performance after intensive bending cycles. These findings enable broader applications of organic materials in high-temperature electronics and energy storage devices.

Controlling the structure of thermoelectric materials on all length scales (atomic, nanoscale and mesoscale) relevant for phonon scattering makes it possible to increase the dimensionless figure of merit to more than two, which could allow for the recovery of a significant fraction of waste heat with which to produce electricity. New materials to generate electricity from heat Thermoelectric materials offer ways to transform heat to electrical energy and vice versa. Here, the authors tailor the architecture of a bulk thermoelectric material, the semiconductor lead telluride, to maximize thermoelectric performance. They achieve phonon scattering on three different length scales. Atomic-scale doping, nanometer-scale endotaxial precipitation and mesoscale grain-boundary structures were introduced to the material to drastically reduce its thermal conductivity and subsequently achieve a very high thermoelectric figure of merit. These advances could aid in the design of advanced thermoelectric materials that can be used to recover waste heat. With about two-thirds of all used energy being lost as waste heat, there is a compelling need for high-performance thermoelectric materials that can directly and reversibly convert heat to electrical energy. However, the practical realization of thermoelectric materials is limited by their hitherto low figure of merit, ZT , which governs the Carnot efficiency according to the second law of thermodynamics. The recent successful strategy of nanostructuring to reduce thermal conductivity has achieved record-high ZT values in the range 1.5–1.8 at 750–900 kelvin 1 , 2 , 3 , but still falls short of the generally desired threshold value of 2. Nanostructures in bulk thermoelectrics allow effective phonon scattering of a significant portion of the phonon spectrum, but phonons with long mean free paths remain largely unaffected. Here we show that heat-carrying phonons with long mean free paths can be scattered by controlling and fine-tuning the mesoscale architecture of nanostructured thermoelectric materials. Thus, by considering sources of scattering on all relevant length scales in a hierarchical fashion—from atomic-scale lattice disorder and nanoscale endotaxial precipitates to mesoscale grain boundaries—we achieve the maximum reduction in lattice thermal conductivity and a large enhancement in the thermoelectric performance of PbTe. By taking such a panoscopic approach to the scattering of heat-carrying phonons across integrated length scales, we go beyond nanostructuring and demonstrate a ZT value of ∼2.2 at 915 kelvin in p-type PbTe endotaxially nanostructured with SrTe at a concentration of 4 mole per cent and mesostructured with powder processing and spark plasma sintering. This increase in ZT beyond the threshold of 2 highlights the role of, and need for, multiscale hierarchical architecture in controlling phonon scattering in bulk thermoelectrics, and offers a realistic prospect of the recovery of a significant portion of waste heat.

Electrospinning is from the academic as well as technical perspective presently the most versatile technique for the preparation of continuous nanofi bers obtained from numerous materials including polymers, metals, and ceramics.

This versatile and scalable ‘patterned regrowth’ fabrication process produces one-atom-thick sheets containing lateral junctions between electrically conductive graphene and insulating hexagonal boron nitride, paving the way for flexible, transparent electronic device films. Towards atom-thick integrated circuits This paper reports a new technique for the production of one-atom-thick thin films combining a conductor (graphene) with insulating hexagonal boron nitride (h-BN). The process, called patterned regrowth, allows for the growth of electrically isolated graphene devices in continuous two-dimensional sheets with well-defined heterojunctions ensuring that the patterned domains retain distinct electronic properties. Devices made using this approach are likely to remain mechanically flexible and optically transparent, allowing transfer to a range of substrates for flexible, transparent electronics. The introduction of two-dimensional semiconducting materials into the sheets would combine the three key building blocks (insulator, metal and semiconductor) of modern integrated circuitry. Precise spatial control over the electrical properties of thin films is the key capability enabling the production of modern integrated circuitry. Although recent advances in chemical vapour deposition methods have enabled the large-scale production of both intrinsic and doped graphene 1 , 2 , 3 , 4 , 5 , 6 , as well as hexagonal boron nitride ( h -BN) 7 , 8 , 9 , 10 , controlled fabrication of lateral heterostructures in these truly atomically thin systems has not been achieved. Graphene/ h -BN interfaces are of particular interest, because it is known that areas of different atomic compositions may coexist within continuous atomically thin films 5 , 10 and that, with proper control, the bandgap and magnetic properties can be precisely engineered 11 , 12 , 13 . However, previously reported approaches for controlling these interfaces have fundamental limitations and cannot be easily integrated with conventional lithography 14 , 15 , 16 . Here we report a versatile and scalable process, which we call ‘patterned regrowth’, that allows for the spatially controlled synthesis of lateral junctions between electrically conductive graphene and insulating h -BN, as well as between intrinsic and substitutionally doped graphene. We demonstrate that the resulting films form mechanically continuous sheets across these heterojunctions. Conductance measurements confirm laterally insulating behaviour for h -BN regions, while the electrical behaviour of both doped and undoped graphene sheets maintain excellent properties, with low sheet resistances and high carrier mobilities. Our results represent an important step towards developing atomically thin integrated circuitry and enable the fabrication of electrically isolated active and passive elements embedded in continuous, one-atom-thick sheets, which could be manipulated and stacked to form complex devices at the ultimate thickness limit.

A conceptually new type of transistor, based on a strongly correlated material, allows external control of a macroscopic electronic phase transition, and gives rise to a non-volatile memory effect. A promising vanadium dioxide transistor The principle behind the classic transistor is the use of an external voltage to control the electrical conductivity of a nanometre-sized conducting channel near the surface of the device material. This paper reports the development of a conceptually new type of transistor in which an electric field controls the electronic properties of the whole of the device. This is made possible by using, instead of silicon, the strongly correlated material vanadium dioxide. The application of just one volt, at room temperature, switches the material from being an insulator to having a metallic ground state on a macroscopic scale and gives rise to a non-volatile memory effect, making it of great practical interest for applications including the remote transmission of electrical signals and voltage-tunable optical switching. In the classic transistor, the number of electric charge carriers—and thus the electrical conductivity—is precisely controlled by external voltage, providing electrical switching capability. This simple but powerful feature is essential for information processing technology, and also provides a platform for fundamental physics research 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 . As the number of charges essentially determines the electronic phase of a condensed-matter system, transistor operation enables reversible and isothermal changes in the system’s state, as successfully demonstrated in electric-field-induced ferromagnetism 2 , 3 , 4 and superconductivity 5 , 6 , 7 , 8 , 9 , 10 . However, this effect of the electric field is limited to a channel thickness of nanometres or less, owing to the presence of Thomas–Fermi screening. Here we show that this conventional picture does not apply to a class of materials characterized by inherent collective interactions between electrons and the crystal lattice. We prepared metal–insulator–semiconductor field-effect transistors based on vanadium dioxide—a strongly correlated material with a thermally driven, first-order metal–insulator transition well above room temperature 17 , 18 , 19 , 20 , 21 , 22 , 23 —and found that electrostatic charging at a surface drives all the previously localized charge carriers in the bulk material into motion, leading to the emergence of a three-dimensional metallic ground state. This non-local switching of the electronic state is achieved by applying a voltage of only about one volt. In a voltage-sweep measurement, the first-order nature of the metal–insulator transition provides a non-volatile memory effect, which is operable at room temperature. Our results demonstrate a conceptually new field-effect device, extending the concept of electric-field control to macroscopic phase control.