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Oil-immersed insulation paper (OIP) bushing is one of the most important equipment in power transmission and distribution systems. Moisture is one of the most serious factors that affect the insulation status of OIP bushing. In this paper, the OIP bushing was assumed to be in a stable and simplicity condition, and then the transient moisture distribution of capacitor core and its effects on the electric field were studied. First, by dissecting a 110 kV OIP bushing, the specific sizes for modelling were obtained. Afterwards, a moisture diffusion model for OIP bushing was established based on COMSOL Multiphysics software, and it was also verified by moisture diffusion experiment. Then, the moisture distribution for different conditions were obtained and analyzed. Finally, a model for the electric field of OIP bushing was established, and then the effects of moisture on the electric field were studied.

Purpose. To substantiate the breakdown mechanism of capacitor paper on the basis of numerical-field models with segmented cross-sections of cylindrical volumes of air and water, and also use the proposed models to determine the breakdown strength of air in micron-sized gaps under normal conditions. Methodology. The model bases on a finite element solution to an electrostatic problem in a volume of capacitor paper consisting of cellulose and pores with air and water. First, the possible scenarios for the growth of breakdown in capacitor paper are analyzed and to the conclusion is made, that complete breakdown developed from a partial breakdown in the air cavity. A brand of capacitor paper is chosen in such a way that when its thickness changed, the breakdown strength of the electric field changed over a wide range. Then, for the paper with the lowest average electric field intensity the possibility of explaining the complete breakdown by the breakdown of air segments on the basis of the Paschen dependence is checked. Further points of the obtained dependence by constructing models of papers of the same brand and a different thickness under the assumption of the similarity of electrostatic fields are determined. As such a criterion, the constancy of the equivalent effective permittivity are taken. Results. The dependence of the breakdown strength of the air in the range of 1.36...5.54 μm under normal conditions is determined. The obtained relationship is between the Peschot and Taev curves. Originality. For the first time, the possibility of indirectly estimation the breakdown strength of an insulating material using an electrostatic field model is indicated. Practical value. The proposed method for the numerical calculation of the breakdown voltage of air inclusions in the presence of water inclusions in the thickness of solid insulation can be applied to other types of solid thin-layer insulation., Полученная в работе зависимость напряженности электрического поля воздуха от длины разрядного промежутка удовлетворительно объясняет значения пробивных напряжений образцов конденсаторной бумаги при изменении их марок и толщины. Построена зависимость пробивной напряженности воздуха при нормальных условиях в диапазоне 1,36…5,54 мкм на основании расчета электростатических полей в моделях конденсаторной бумаги с сегментными поперечными сечениями цилиндрических объемов воздуха и воды. Проведено сопоставление полученной зависимости с известными экспериментальными данными. Полученные данные в диапазоне 2…5,54 мкм наиболее близки экспериментальным данным Пешо.

Utilizing graphene-based hybrid papers or films as multifunctional electrodes has become the focus of clean energy devices due to the beneficial combination of their excellent electrical properties and multiple functions. However, limited attention has been paid to such hybrid papers with both outstanding mechanical and electrochemical properties. Recently, we fabricate rationally designed TiO2-B nanofibrils reinforced graphene paper, which can achieve high mechanical strength (88.5 MPa) without sacrificing their electrochemical properties. They further deliver capacities of 231 mAh g−1 (408.9 mAh cm−3) for Li-ion electrode and 201 mAh g−1 (355.8 mAh cm−3) for Na-ion electrode respectively at the same current density of 33.5 mA g−1. The outstanding mechanical stability of as-prepared hybrid electrode is demonstrated with a prototype of a bendable Li-ion capacitor. Besides, the as-prepared electrodes also reveal great potential to serve as light weight and ultrathin electromagnetic interference shielding materials. Single layer of hybrid paper exhibits a shielding effectiveness of over 10 dB (corresponding ∼90% shielding). These results prove that TiO2-B nanofibrils reinforced graphene paper can serve as a multifunctional flexible electrode for diverse applications. Moreover, this work also demonstrates a novel strategy on how to enhance mechanical properties for those flexible electrodes.

In this study, the multifunctionality of structural dielectric capacitor made by integrating graphene oxide paper into carbon fibre reinforced composite has been investigated. The study is based on an earlier work on the use of graphene oxide for dielectric material in the structural dielectric capacitor, in which electrical properties have been characterized. In this work, an in-depth study on electrical and mechanical properties of this kind of structural dielectric capacitor have been carried out. In addition, the multifunctional efficiency of structural dielectric capacitors were evaluated and compared with existing structural dielectric capacitors. Through experiments, it is revealed that both electrical and mechanical properties of the structural dielectric capacitors were significantly enhanced by interleaving a graphene oxide paper in the middle of composite. Therefore, the multifunctional efficiency of this kind of structural dielectric capacitors has been ultimately improved, indicating the excellent potential of graphene oxide paper in the development of multifunctional materials for energy storage, potentially for high-strength required applications, such as electric vehicles and unmanned aerial vehicles.

Measurements of capacitors made with paper sheets reveal a significant decrease in capacitance with increasing frequency from 10 to 100,000 Hz, offering a simple demonstration of complex dielectric phenomena using common equipment., 3 pages, 2 figures

Hybrid printed electronics, in which printed structures and silicon-based components co-exist will likely be among the first commercial solutions. In this case the paper substrate acts much in the same way as circuit boards, containing conductive tracks and acting as a carrier for the electrical components. It is important to consider the contacting of the components to be able to produce low resistance electrical contacts to the conductive tracks. Supercapacitors are able to deliver a large amount of current in a short time and are a good option for short term energy storage and if the printed product is to be used only one, or a few times, it can be the only power source needed. When manufacturing printed electronics, the overall resistance of the printed tracks as well as the contact resistance of the mounted components will add up to the total resistance of the system. A high resistance will cause a voltage drop from the power source to the component. This will waste power that goes to Joule heating and also the voltage and current available to components may be too low to drive them. If the intention is to use a power supply such as batteries or solar cells this becomes a limitation. In this article have been tested several conductive adhesives used to contact paper based supercapacitors to ink jet printed silver tracks on paper. The best adhesive gives about 0.3 Ω per contact, a factor 17 better compared to the worst which gave 5 Ω. The peak power that is possible to take out from a printed system with a flexible battery and super capacitors is about 10 times higher than compared with the same system with only the battery.

The film-impregnated dielectric under operating conditions is subject to prolonged exposure to electric and thermal fields, as well as mechanical loading. In addition to critical partial discharges, the most serious drawback that impairs the film and condenser reliability in general is the deterioration of the electro-physical characteristics of the polypropylene film and liquid dielectric due to the gradual dissolution of the polymer in the liquid dielectric, which is determined by their chemical composition. This interaction of components, which was investigated in detail, has a thermo activation nature, which relates to the processes of rearrangement of atoms or molecules with the overcoming of potential barriers, and is manifested in the swelling of the polypropylene film with subsequent dissolution of the amorphous component in the polymeric component. As a consequence, irreversible structural changes of the film occur, which lead to a decrease in its electrical and mechanical strength, as well as to an increase in the dielectric loss of the liquid dielectric. Capacitor (Fig. 1 (a)) is designed to provide high-frequency communication at frequencies from 24 to 1500 kHz in power lines with a nominal voltage of 35, 110, 150, 220, 330, 500 kV AC 50 and 60 Hz. Coupling capacitor impregnated with environmentally friendly liquid - condenser oil. The short-circuits consist of capacitor sections (Fig. 1 (b)): a thin layer of dielectric is laid between two thin wide metal strips, and the dielectric film is placed on top and below the metal strips - capacitor covers. This paper gives the detail analysis of dielectric properties of capacitor paper.

This article is a result of measuring the dielectric constant of a dielectric used in studying the influence of dielectrics on the antennae reflection coefficients. A paper having a density of 0.797 g/cm3, moisture content of 0% and temperature of 210C, is used as a dielectric. Although the literature provides a lot of data on the dielectric properties of wood and paper, without direct measurement of the dielectric constant it is impossible to know its amount for the dielectric used in the defined frequency range. Dielectric constant measurements are performed in the frequency range from 100 Hz to 100 kHz, while the frequency range of its impact on the aperture antenna reflection coefficients is up to 2 GHz. The frequency range from 100 KHz to 10 GHz is interpolated and fitted by using measurements and available literature data and by respecting physical influences and phenomena and functional changes of the dielectric constant of paper within the given range

Here we report a self-powered origami paper analytical device (oPAD) that uses an aptamer to recognize an analyte, a glucose oxidase (GOx) tag to modify the relative concentrations of an electroactive redox couple, and a digital multimeter (DMM) to transduce the result of the assay. The sensor is self-powered in that it self-generates an electrical signal so that the read-out process is similar to testing a battery. The principle of the sensor is illustrated in Scheme 1. Briefly, the device is printed on a single piece of paper, folded into a three-dimensional (3D) configuration, and then laminated in plastic. An aliquot of sample is loaded at the inlet, split into two channels, and then directed to microbeads entrapped within the channels. In one channel, an aptamer immobilized on microbeads binds to the target and releases a GOx-labeled DNA strand that flows downstream. No aptamer is present on the microbeads in the other channel, which is used as a control. The split fluids terminate in an hour-glass-shaped, two-compartment electrochemical cell. The waist of the hour glass serves as a salt bridge between the two half cells. In one of the half cells, GOx catalyzes the oxidation of glucose, which in turn results in conversion of Fe(CN)63− to Fe(CN)64−.The difference in concentrations of Fe(CN)63− and Fe(CN)64− in the sensing half cell and control half cell results in a voltage that is used to charge a capacitor. When the switch (lower part of Scheme 1) is closed, the capacitor discharges through the DMM. The capacitor provides a high instantaneous current, in effect an amplified current, and hence a higher sensitivity than a direct current measurement.

The partial discharge in lower porcelain shell of oil paper insulation bushing is one of the important reasons for transformer failures. Based on the analysis of the oil paper insulation bushing structure characteristics, the finite difference time domain simulation model of the partial discharge in lower porcelain shell is established. And the path of UHF signal of partial discharge is obtained that the signal spreads through the insulation between capacitor screens and oil passage to the outer space. Then the lower porcelain shell partial discharge detection method based on the space UHF signal is proposed and verified.

The term supercapacitor (or ultracapacitor) is used to indicate an electrochemical capacitor capable of storing charge through a capacitive process occurring in the electrical double layer formed at the interface between an electronic conductor (i.e., the electrode) and an electrolytic solution (e.g., non-aqueous electrolyte). The increasing demand for improved electrochemical energy storage systems continually boosts research efforts toward new materials, configurations and production processes, both for batteries and supercapacitors. The development of hybrid devices (e.g., where one electrode stores charge through a faradaic process and the other through a non-faradaic process) has also exploited progress in both the battery and supercapacitor fields. However, not all investigated materials are promising or industry-relevant, contrary to the claims in many research works. For example, complications related to the upscaling of lab-scale experiments hamper the exploitation at industrial scale. For these reasons, it is essential to define the best-practice methods to obtain reasonable predictions for supercapacitor materials and device testing. Also, many battery electrode materials are explored as supercapacitor electrode materials. However, not all battery materials can be considered as candidate electrode materials for hybrid devices. Only those materials with a suitable crystal structure for high rate capability and good cycling stability are appropriate.

Orientador: José Antonio Siqueira Dias Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Resumo: Sensores capacitivos são aqueles que trabalham baseados no funcionamento de um capacitor, ou seja, a formação de um campo elétrico a partir de dois eletrodos energizados e separados de forma específica por um material dielétrico, material este que, ao variar, promove variação no campo que por sua vez, promove alteração na corrente ou na tensão que passam pelos eletrodos. Estes recebem tensão ou corrente e/ou um ou outro retornam ao circuito de processamento, de maneira que a variação interpretada traduz a variação do meio em questão. A forma e os materiais construtivos dos eletrodos determinam o modo de funcionamento do sensor. O objetivo deste trabalho é construir um sensor capacitivo do tipo PCB - Print Circuit Board avaliando os resultados de várias amostragens para determinar a viabilidade deste dispositivo de medição. Os experimentos demonstrados indicaram leituras positivas de variação de capacitância em função de amostras de polpa com umidades entre 90 e 94% com significativa repetibilidade. Os desvios padrão calculados demonstraram a pequena dispersão em relação às amostras Abstract: Capacitive sensors are sensors that work based on the capacitor principles, it means, an electric field is created from two energized wires with specific dielectric environment that can changes and due the changes can change the current or voltage that goes by through the wires. The wires that connect sensor and processor circuit deliver the current or voltage to the processor that defines the variation of the environment. The form and base materials of the sensors determine how the sensors work. The scope of this work is to build a capacitive sensor type PCB - "Print Circuit Boarding" and evaluate the results and feasibility of this type of capacitive sensor. The experiment had demonstrated positive results of capacitive variation face to samples of pulps with different levels of moisture between 90 and 94% with reasonable repeatability. The standard deviations were calculated and had demonstrated small spread regarding the samples indicating good work of the prototype Mestrado Eletrônica, Microeletrônica e Optoeletrônica Mestre em Engenharia Elétrica

Kraft paper is used extensively in the electricity supply industry for the insulation of HV apparatus, such as transformers, capacitors and cables. Because of the fibrous nature of the paper, many layers are stacked or rolled to obtain the required electric strength. The insulation is thus a combination of cellulose and an impregnating fluid, which may be a liquid, a gas or vacuum. The dielectric properties of such a system depend on the dryness, temperature, frequency and the degree of mechanical compression. Although the effects of moisture, temperature and frequency on the dielectric properties of kraft paper have been studied, very little work has been done on the effect of compressive stress, particularly long-term effects. Results are presented of measurements, in the frequency range 50 Hz to 20 kHz, of the effects of compressive stress and temperature on the real and imaginary parts of the complex relative permittivity of a multilayer stack of dry kraft paper under vacuum. The variations of the dc resistance with compressive stress and temperature also are reported. Results are given of the variation of the dielectric properties of a stack of paper following a step change in either the temperature or the air pressure. The long-term variations are attributed to the slow diffusion of ions through the stack, particularly those held at the interfaces between layers.

Power capacitors are widely used for regulating voltage and improving the power factor of power systems, and the type in most frequent use today are capacitors made of oil-impregnated paper film, a growing number of which will soon have been in operation in the field for 20 years. This has prompted the authors to study techniques for diagnosing deterioration in oil-impregnated paper film capacitors. It was found that thermal stress causes deterioration of the insulating paper, which increases the amount of dissolved CO and CO/sub 2/ in the oil and lowers the partial discharge inception voltage, determining the useful lifetime of the capacitor. Based on this idea, techniques have been proposed for diagnosing deterioration, consisting of caution level and danger level, from actual stress in the field. Further, a trial calculation was made for the number of years and months it takes for a capacitor to reach this caution level, based on an investigation of capacitors in service for many years.

In this paper, a flexible film electrode was prepared by depositing graphene nanosheets on carbon nanotube paper as a self-standing electrode for high-performance electrochemical capacitors. The composite film has a layered structure, where carbon nanotubes were efficiently intercalated in the layer of graphene nanosheets. The hierarchical structure of graphene nanosheet/carbon nanotube paper electrodes shows lower resistance to ions and electron transport. The unique electrodes exhibit high-rate capability and long-term cycling ability. A quasi-rectangular shape of CV curve can still be maintained even at a high scan rate of 10 V s−1. The capacitance decay was only 6.9% after 10 000 cycles at a current density of 6.4 mA cm−2.

A paper actuator was fabricated from poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) by a wet process without organic solvents. The paper actuator had a capacitor structure, with a cationic polymer as an insulating layer sandwiched between two PEDOT:PSS films as the electrodes. The thickness of the paper actuator was approximately 36 mm. We measured its displacement as a function of applied voltage and frequency; the maximum displacement was 2.2 mm at 1.5 V and 1 Hz.

To effectively improve the power density and rate capability of layered double hydroxide (LDH) based supercapacitors, a hybrid supercapacitor (HSC) comprising of hierarchical ultrathin NiAl-LDH nanosheet arrays on carbon nanotube paper (CNP-LDH) is developed with porous graphene nanosheets as the negative electrode for the first time. SEM image shows that hierarchical NiAl LDH nanosheet arrays are assembled by numerous ultrathin nanosheets with thickness of a few to tens of nanometers. Remarkably, with an operating voltage of 1.6 V, the HSC possesses a high energy density of 50.0 Wh kg−1 at an average power density of 467 W kg−1. Even at a fast discharging time of 3.9 s, a high energy density (23.3 Wh kg−1) could also be retained at a power density of 21.5 kW kg−1. Moreover, the HSC exhibits cycling stability with a retention rate of 78% after 5000-cycle charge-discharge test at 5 A g−1. The results inspire us to propose our high-performance CNP-LDH as a promising electrode for energy storage applications.

This paper deals with a low-cost method for the assembly of flexible substrate antennas and UHF RF identification silicon (Si) chips. Such a method exploits a magnetic coupling mechanism, thus not requiring for galvanic contacts between the Si chip and antenna itself. The magnetic coupling is established by a planar transformer, the primary and secondary windings of which are implemented on flexible substrate and Si chip, respectively. As a result, the Si chip can be assembled on the antenna with a mere placing and gluing process. First, the idea has been validated by theory. Electromagnetic simulations of a square heterogeneous transformer (1.0-mm side) show a maximum available power gain (MAG) of -0.4 dB at 868 MHz. In addition, the heterogeneous transformer is also quite tolerant with respect to misalignment between primary and secondary. An offset error of 150 μm reduces the MAG to - 0.5 dB. A sub-optimal matching strategy, exploiting a simple on-chip capacitor, is then developed for antennas with 50- Ω input impedances. Finally, the idea has been experimentally validated exploiting printed circuit board (PCB) prototypes. A PCB transformer (1.5-mm side) and a transformer rectifier (two-diode Dickson multiplier) have been fabricated and tested. Measurements indicates a MAG of -0.3 dB at 868 MHz for the transformer and the capability of the developed rectifier to supply a 220-kΩ load at 1.5 V with a - 2-dBm input power.

Electronic capacitors were constructed via hand-printing on paper using pencil graphite. Graphite traces were used to draw conductive connections and capacitor plates on opposing sides of a sheet of standard notebook paper. The paper served as the dielectric separating the plates. Capacitance of the devices was generally < 1000 pF and scaled with surface area of the plate electrodes. By combining a pencil-drawn capacitor with an additional resistive pencil trace, an RC low-pass filter was demonstrated. Further utility of the pencil-on-paper devices was demonstrated through description of a capacitive force transducer and reversible chemical sensing. The latter was achieved for water vapor when the hygroscopic cellulose matrix of the paper capacitor’s dielectric adsorbed water. The construction and demonstration of pencil-on-paper capacitive elements broadens the scope of paper-based electronic circuits while allowing new opportunities in the rapidly expanding field of paper-based sensors.

International audience; This paper reports the first flexible electrostatic kinetic energy harvester (e-KEH) with electret nanofibrous films obtained by electrospinning and paper-based electrodes. The nanofibrous electret outperforms plenary thin film Parylene in the storage stability of charge: the surface potential is stabilized within 1 day, without any obvious minishing during the following 9 days. The output power of the device is improved by implementing multiple electret layers, where the optimal number of electret layer is 3. With a finger tapping activation, this first prototype with the optimal configuration gives a maximum peak power of 45.6 μW with the optimal load of 16 MΩ. Working with a full-wave diode rectifier and a storage capacitor of 10nF, the voltage reaches 8.5 V with 450 strokes.

Supercapacitor have attracted much attention due to its fast power supply, long cycle life, simple principle, etc. Supercapacitors are widely used in consumer electronics. Activated carbon is a typical material for electric double layer capacitor. Here, we study the electrochemical performance of an activated carbon (TF-B520) bulky paper electrode made by vacuum filtration method. Cyclic Voltammetry and Constant Current Charge/Discharge were used to test the electrode capacitance and the rate performance. The results showing that TF-B520 activated carbon balky paper electrodes have the highest capacitance of 120F/g at scan rate 1mV/s and good capacitor behaviour at scan rate below 20mV/s and current density below 250mA/g.

This special issue of Analog Integrated Circuits and Signal Processing presents the extended versions of selected papers from the 31th NORCHIP conference which was held in Vilnius, Lithuania, November 11–12, 2013. The 31th NORCHIP conference had 56 registered participants and 45 papers were presented during the 2 days the conference lasted whereof 30 papers were presented in 10 oral lecture sessions in two tracs, 12 papers were presented in two poster sessions, the 3 presentation, in session on Education and Training. The 3 invited presentations (first—Romualdas Navickas, ‘‘Self-formation in high speed integrated circuits’’, second—Petar Popovski, ‘‘Wireless technologies competing for a seat in the 5G bandwagon’’, and third—Ville Eerola, ‘‘Correlator design and implementation for GNSS receivers’’) were given. However, more submissions are originating from the local area of the conference (only one accepted paper was from a non-European country). From the contributed papers nine papers have been selected for this special issue. The selection of the papers for this special issue is based on quality criteria and they reflect the topics in analog circuit design highlighted during the conference, the feedback of the session chairs and the selected papers all contain contributions that will be of interest to the reader. The papers are briefly introduced below. The two first papers present two RF amplifiers. In the first paper ‘‘Triple Cascaded Current-Reuse Low Noise Amplifier’’ Muh-Dey Wei, Sheng-Fuh Chang, Renato Negra present a triple cascaded current-reuse CMOS low noise amplifier (LNA) for 3.5 GHz WiMAX application. Three commonsource amplifiers are stacked and reuse the same current. This triple cascaded topology is able to enhance power gain but needs two coupling networks which costs enormous chip size. In order to have reasonable chip size, two coupling methods are investigated. For obtaining simultaneous input and noise matching, an additional capacitor is employed to adjust quality factor and reduce the gate induced current noise. The proposed chip is implemented in 180 nm CMOS technology. The measurement results show a maximum power gain of 21.7 dB and minimum noise figure of 3.11 dB. The chip size is 1.05 9 0.93 mm including all pads and the power consumption is 5.16 mW with a supply voltage of 1.5 V. In the second paper ‘‘A 1 V Power Amplifier for 81–86 GHz E-band’’ authors Tobias Tired, Henrik Sjoland, Carl Bryant and Markus Tormanen describe the design and layout of a two stage SiGe E-band power amplifier using a stacked transformer for output power combination. In EMsimulations with ADS Momentum, at E-band frequencies, the power combiner consisting of two individual single turn transformers performs significantly better than a single 2:1 transformer with two turns on the secondary side. Imbalances in the stacked transformer structure are reduced with tuning capacitors for maximum gain and output power. At 84 GHz the simulated loss of the stacked transformer is as low as 1.35 dB, superseding the performance of an also presented alternative power combiner. The power combination allows for a low supply voltage of 1 V, which is beneficial since the supply can then be shared between the power amplifier and the transceiver, thereby eliminating the need of a separate voltage regulator. To improve the gain of the two-stage amplifier it employs a capacitive cross-coupling technique not yet seen in mm-wave SiGe Pas. Capacitive cross-coupling is an effective technique for gain enhancement but is also sensitive to process variations as shown by Monte Carlo simulations. To mitigate this two R. Navickas (&) Department of Computer Engineering, Vilnius Gediminas Technical University, Naugarduko str. 41, r. 437, 03227 Vinius, Lithuania e-mail: romualdas.navickas@vgtu.lt

Results of Frequency Domain Spectroscopy measurements are known to be largely influenced by environmental conditions, such as the temperature. Because field measurements, last hours after de-energizing the transformer, the ambient temperature may affect the results. Especially in cold regions of the world, extreme care are required to interpret the results when performing tests at relatively low surrounding temperatures. A better understanding and analysis of the dielectric test results are therefore only possible with a clear understanding of the physical behavior of the insulation system in response to the ambient conditions. In this contribution, the dielectric behavior of a composite oil paper insulation system has been explained from the properties of Debye basic model. A series of experiments have been performed under controlled laboratory conditions with preset moisture content inside the insulation. The equivalent circuit parameters of a laboratory made oil paper condenser bushing model were obtained using a non-linear optimization procedure. Since the dielectric parameters values are geometry dependent, poles, calculated from resistances and capacitances, were used as they are independent of the geometry. It was shown that the poles can be regarded as parameters able to be used for insulation condition assessment.

Hand-written fabrication techniques offer new ways of developing customizable, biodegradable and low-cost electronic systems. In this work, a new level of complexity is demonstrated for hand-written electronics by fabricating passive components, circuits and a sensorsystem on paper. The system comprises a pencil-written graphite force-sensitive-resistor, a pencil-drawn RC-filter, a pen-written half-wave rectifier, and a commercial front-end voltage amplifier. The sensor system exhibits a linear response for pressures up to 1.2 kPa, and a sensitivity of 51 mV kPa-1 . Furthermore, the electrical and mechanical performance of the single components and circuits is studied. Diodes fabricated through pen-written deposition of silver and nickel contacts on amorphous Indium-Gallium-Zinc-Oxide coated paper show rectification ratios up to 1:8. Tensile and compressive bending measurements applied to all pencil-written components for radii down to 0.1 mm indicate minor influence of strain. Similar results are obtained for circuits created from these individual components. Diodes and half-wave rectifiers show a stable behavior when bent to a radius of 5 mm. The presented techniques can enable the development of flexible and eco-friendly wearables and sensors for consumer and healthcare applications, and are an effective way for school-pupils to explore the world of electronics.

This paper reports on the current development of a new Thompson–Lampard calculable capacitor at LNE. The goal is to determine the von Klitzing constant RK at a significant level of uncertainty of about one part in 108. The comparison with other accurate measurements of h/e2 serves as a relevant test of validity of the theory predicting RK = h/e2, a decisive issue within the context of the new SI. Conversely, assuming that this relation is exact, the measurement of RK and thus that of the fine structure constant α can be used for testing quantum electrodynamics theory. The mechanical structure of the new LNE calculable cross capacitor has been designed and a new set of electrodes has been fabricated. The assembling of the calculable capacitor is in progress.

A capacitor formed of fluid-impregnated paper metalized on one side and a polymer film results in a relaxation peak caused by the much more rapid polarization of the dielectric fluid impregnated paper relative to the polymer film. This results in the capacitance being a function of frequency, with a substantial increase in capacitance at very low frequencies. A theory for such a capacitor is developed and compared with measurements on actual capacitors with relatively good agreement. The implications of the theory for discharge current and discharge efficiency are discussed.

We report the rapid prototyping of passive electrical components (resistors and capacitors) on plain paper by an additive and parallel technology consisting of supersonic cluster beam deposition (SCBD) coupled with shadow mask printing. Cluster-assembled films have a growth mechanism substantially different from that of atom-assembled ones providing the possibility of a fine tuning of their electrical conduction properties around the percolative conduction threshold. Exploiting the precise control on cluster beam intensity and shape typical of SCBD, we produced, in a one-step process, batches of resistors with resistance values spanning a range of two orders of magnitude. Parallel plate capacitors with paper as the dielectric medium were also produced with capacitance in the range of tens of picofarads. Compared to standard deposition technologies, SCBD allows for a very efficient use of raw materials and the rapid production of components with different shape and dimensions while controlling independently the electrical characteristics. Discrete electrical components produced by SCBD are very robust against deformation and bending, and they can be easily assembled to build circuits with desired characteristics. The availability of large batches of these components enables the rapid and cheap prototyping and integration of electrical components on paper as building blocks of more complex systems.

A theoretical analysis of the possibility of increasing the electrical strength, Es, of solid dielectrics has been carried out. It is shown that the local electric field intensity in regions of defect (pores) aggregation can be about 5 times larger than the average field applied to the paper dielectric. This is one reason for the fact that the electrical strength of ‘large-porous’ electrical capacitor papers (CPs) are only a fifth to a third of those of ‘fine-porous’ dielectrics such as hydrated cellulose films. To enhance the value of Es of CPs noticeably it is necessary either to prevent the pores exceeding some critical size or to provide a sufficiently small dispersion of the pore sizes. Simple fabrication methods of dielectric composite papers with CPs as a main component—referred to as composite papers—give materials with values of Es exceeding 110 kV/mm, which is higher than the values reached previously.

Since rare metals have many advantages in high advanced technology fields, a stable supply of these metals is very important in a highly industrialized country like Japan. Developing an urban mine in which these metals are condensed is a possible solution to this problem. In this report, we discuss the recycling of tantalum from capacitor scrap via a chloride process. The results are as follows : 1) Capacitor scraps reacted with Cl_2 gas at about 623K producing TaCl_5,while Ta_2O_5 and MnO_2 did not react with Cl_2 and remained as residues. 2) Mn content in recovered TaCl_5 was decreased to 0.007%, but that in the residue was enriched to 13.2%. 3) In the case of capacitor chlorination, a low reaction rate of 55% was obtained. Some pretreatment like crushing must be considered. 4) Chlorination of ground capacitor scrap powder after reductive leaching gave a high reaction rate of 95% and a low Mn content in TaCl_5 of less than 1ppm. 5) The probable process for recycling of Ta capacitor scrap corresponding to advanced material production was proposed based on the above results.

Based on measurements, the strength of synthetic oil impregnated capacitor paper (Askarel) to dc and ac voltage 1.2/50-?s voltage surges and switching surges of various wavefront duration are discussed. The results of measurements are compared with the performance figures of mineral oil impregnated capacitor paper. The diminishing effect of the number of lightning and switching surges and their amplitude upon electric strength and of initial voltage partial discharge is investigated.

Several new liquid impregnants for capacitors have been suggested as possible alternatives to PCB's which are being replaced in view of their harmful effects. The application of castor oil, a vegetable product, has been studied in the authors' laboratory with the same objective. The results of the investigations have shown that castor oil possesses most of the favorable properties of a good impregnant. This paper gives a detailed analysis of the dielectric behavior of the oil alone and all-paper capacitors impregnated with castor oil.

In view of its non-toxicity, and good dielectric properties, castor oil, a polar liquid dielectric of vegetable origin is suggested as a possible alternative to PCB's for capacitor applications. In this paper the dielectric properties (including partial discharge behavior), of all-polypropylene and paper-polypropylene capacitors with castor oil as impregnant, are reported. The paper also contains results of life studies conducted under accelerated electrical and thermal stresses when they are occurring both individually and combined. The data obtained have been statistically analyzed and approximate life of the system calculated by linear extrapolation.

Fundamental-mode Pierce oscillators in the 250-300-MHz range have been realized utilizing a unique form of a bulk-acoustic-wave (BAW) resonator. Phase noise greater than -100 dBc/Hz (1-kHz offset) has been extrapolated from data collected on oscillators operating at -22 and -24 dBm. Higher power levels to +6 dBm have been achieved. A linear-model design was used. The circuit topology used and resonator fabrication technique shows great promise for the creation of MMIC circuits in the 200-MHz-2-GHz range.

A theoretical and experimental comparison is made of the performance of GaAs MESFET's with and without negative feedback. The devices are fabricated using a six-step MMIC process, which utilizes polyimide for low-capacitance crossovers and silicon nitride for MIM capacitors. Typical RF performance is 9-dB gain with noise figure less than 4 dB from 100 MHz to 3 GHz. The greatest bandwidth is achieved by incorporating a 3 1/2 turn, low Q inductor, which is connected in series with the feedback resistor and is wrapped around the perimeter of the chip to conserve die area.

The design and performance of GaAs FET oscillators operating near 36 GHz are presented. The oscillators used readily available GaAs FET's and were built in a microstrip circuit configuration. An output power of about +8 dBm was obtained with two devices in a single oscillator.

The characteristic impedance influences of superconducting packaging systems (in particular, Josephson packaging) on the degradation in transmitted signal rise time, amplitude distortions and crosstalk, signal propagation delay, and amplitude decay at the inductive and resistive connectors with matched capacitors are quantitatively evaluated by using the ASTAP computer simulation. The present choice of the characteristic impedance Z/sub 0/ = 10- 12 Omega for a superconducting stripline is inadequate. Higher impedances of Z/sub 0/=40-50 Omega are useful from the standpoint of noise performance improvement. At the same time, a higher impedance choice can make the ground connector numbers of each connector decrease, which is preferable for a large-scale packaging system.

It is proposed to construct a simple "crossoverless" Iumped-element circulator, which can be made without sophisticated thin-film processing. The circulator can be described by a "delta connected" equivalent circuit. A simple capacitor arrangement can be used to influence the three eigenvalue phases of the circulator independently, thus permitting this circulator to be maximized systematically. A set of computer-generated eigenvalues gives insight into the behavior of the device under varying operating conditions. Preliminary measurements using a very simple pattern on a 0.650-in-diam ferrite substrate show a 20-dB bandwidth of 10 percent and an insertion loss < 1 dB (0.3 dB/min) at L band.

In this paper, we present a simple yet smart electro-fluidic platform that enables automatic time control in a very affordable and simple manner. The system is based on the electric detection of a fluid front when it crosses a particular area of a paper strip. The detection can be used to trigger the sequential activation or deactivation of different electronic modules (heating of molecular diagnostics, time interval detection, or readout of test results) with an accuracy within the range of minutes. The whole system is implemented with a few number of discrete electronic components such as transistors, resistors and capacitors that, if required, can be totally fabricated using printed electronics technology. This platform opens new possible applications for paper-based point-of care (POC) diagnostic devices and enables the possibility of these devices to introduce time control functions without the need for any external instrumentation and human action.

Graphic Abstract Single-atom-thick graphene is a particularly interesting material in basic research and applications owing to its remarkable electronic, mechanical, chemical, thermal, and optical properties. This leads to its potential use in a multitude of applications for improved energy storage (capacitors, batteries, and fuel cells), energy generation, biomedical, sensors or even as an advanced membrane material for separations. This paper provided an overview of research in graphene, in the area of synthesis from various sources specially from biomass, advanced characterization techniques, properties, and application. Finally, some challenges and future perspectives of graphene are also discussed.