Voltage Stress on Y Capacitors from Indirect Lightning Pulses According to ED-14/DO-160

Science.gov (United States)

Meier, F.

2012-05-01

Transients due to lightning strikes on an aircraft's fuselage impose stress on the input filters of elec- tronic equipment. Permanent damage can occur when exceeding the voltage handling capacity of filter components causing a short circuit to ground. In ED-14/DO-160, section 22, a number of waveforms and levels are defined which are used to check the airworthiness of avionics equipment. Depending on pro- cedure and level, Y-capacitors are stressed by transient voltages which exceed their dielectric strength. The design engineer's task is a properly select the type and voltage rating of capacitors. With moderate simplifications, a LCR-series network is justified to calculate the peak voltage dependent on the capacitance.

Capacitor assembly and related method of forming

Science.gov (United States)

Zhang, Lili; Tan, Daniel Qi; Sullivan, Jeffrey S.

2017-12-19

A capacitor assembly is disclosed. The capacitor assembly includes a housing. The capacitor assembly further includes a plurality of capacitors disposed within the housing. Furthermore, the capacitor assembly includes a thermally conductive article disposed about at least a portion of a capacitor body of the capacitors, and in thermal contact with the capacitor body. Moreover, the capacitor assembly also includes a heat sink disposed within the housing and in thermal contact with at least a portion of the housing and the thermally conductive article such that the heat sink is configured to remove heat from the capacitor in a radial direction of the capacitor assembly. Further, a method of forming the capacitor assembly is also presented.

Variable Permanent Magnet Quadrupole

International Nuclear Information System (INIS)

Mihara, T.; Iwashita, Y.; Kyoto U.; Kumada, M.; NIRS, Chiba; Spencer, C.M.; SLAC

2007-01-01

A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments

Mechanical states in wound capacitors

International Nuclear Information System (INIS)

Allen, J.J.; Reuter, R.C. Jr.

1989-01-01

The winding process is encountered frequently in manufacturing, such as winding of polymer films and paper, laminated pressure vessel construction, and the manufacture of wound capacitors. The winding of capacitors will typically involve hundreds of plies of conductor and dielectric wound over a core. Due to the large number of layers, the calculation of the mechanical studies within a wound capacitor is a significant computational task. The focus of Part II of this paper is the formulation and application of optimization techniques for the design of wound capacitors. The design criteria to be achieved is a specified uniform wound tension in a capacitor. The paper will formulate an optimization statement of the wound capacitor design problem, develop a technique for reducing the numerical calculation required to repeatedly analyze the capacitor as required by the optimization algorithm, and apply the technique to an example. 4 refs., 13 figs., 4 tabs

Materials for electrochemical capacitors

Science.gov (United States)

Simon, Patrice; Gogotsi, Yury

2008-11-01

Electrochemical capacitors, also called supercapacitors, store energy using either ion adsorption (electrochemical double layer capacitors) or fast surface redox reactions (pseudo-capacitors). They can complement or replace batteries in electrical energy storage and harvesting applications, when high power delivery or uptake is needed. A notable improvement in performance has been achieved through recent advances in understanding charge storage mechanisms and the development of advanced nanostructured materials. The discovery that ion desolvation occurs in pores smaller than the solvated ions has led to higher capacitance for electrochemical double layer capacitors using carbon electrodes with subnanometre pores, and opened the door to designing high-energy density devices using a variety of electrolytes. Combination of pseudo-capacitive nanomaterials, including oxides, nitrides and polymers, with the latest generation of nanostructured lithium electrodes has brought the energy density of electrochemical capacitors closer to that of batteries. The use of carbon nanotubes has further advanced micro-electrochemical capacitors, enabling flexible and adaptable devices to be made. Mathematical modelling and simulation will be the key to success in designing tomorrow's high-energy and high-power devices.

Capacitor discharge engineering

CERN Document Server

Früngel, Frank B A

1976-01-01

High Speed Pulse Technology, Volume III: Capacitor Discharge Engineering covers the production and practical application of capacitor dischargers for the generation and utilization of high speed pulsed of energy in different forms. This nine-chapter volume discusses the principles of electric current, voltage, X-rays, gamma rays, heat, beams of electrons, neutrons and ions, magnetic fields, sound, and shock waves in gases and liquids. Considerable chapters consider the applications of capacitor discharges, such as impulse hardening of steel, ultrapulse welding of precision parts, X-ray flash t

Effect of nuclear radiation on the electrical properties of chemical double layer capacitors

International Nuclear Information System (INIS)

Laghari, J.R.; Hammoud, A.N.

1990-01-01

The effects of nuclear radiation on the electrical properties of chemical double layer capacitors are determined. The capacitors were irradiated in a 2-MW nuclear reactor to different fluence levels. The exposure rate was 2.2 x 10 10 n/cm 2 · s of thermal neutrons, 9.52 x 10 8 n/cm 2 · s of fast neutrons (> 2 MeV), and 1.47 x 10 6 rad/h of gamma radiation. The properties measured during and after irradiation included the capacitance, equivalent series resistance, and open-circuit voltage. The post-irradiation effect on the leakage current was also determined. It was found that while the capacitance increased during irradiation, the equivalent series resistance and the open-circuit voltage decreased slightly during irradiation. Changes in these properties were not permanent s was evident from post-irradiation measurements. The leakage current did not show any significant change with radiation. The results indicate that chemical double layer capacitors can be suitably used as backup power source in electronic equipment operating in a radiation environment with total fluences up to 4.05 x 10 14 n/cm 2

A Two-terminal Active Capacitor

DEFF Research Database (Denmark)

Wang, Haoran; Wang, Huai

2017-01-01

This letter proposes a concept of two-terminal active capacitor implemented by power semiconductor switches and passive elements. The active capacitor has the same level of convenience as a passive one with two power terminals only. It is application independent and can be specified by rated...... voltage, ripple current, equivalent series resistance, and operational frequency range. The concept, control method, self-power scheme, and impedance characteristics of the active capacitor are presented. A case study of the proposed active capacitor for a capacitive DC-link application is discussed....... The results reveal a significantly lower overall energy storage of passive elements and a reduced cost to fulfill a specific reliability target, compared to a passive capacitor solution. Proof-of-concept experimental results are given to verify the functionality of the proposed capacitor....

Fractal Structures For Fixed Mems Capacitors

KAUST Repository

Elshurafa, Amro M.

2014-08-28

An embodiment of a fractal fixed capacitor comprises a capacitor body in a microelectromechanical system (MEMS) structure. The capacitor body has a first plate with a fractal shape separated by a horizontal distance from a second plate with a fractal shape. The first plate and the second plate are within the same plane. Such a fractal fixed capacitor further comprises a substrate above which the capacitor body is positioned.

Fractal Structures For Fixed Mems Capacitors

KAUST Repository

Elshurafa, Amro M.; Radwan, Ahmed Gomaa Ahmed; Emira, Ahmed A.; Salama, Khaled N.

2014-01-01

An embodiment of a fractal fixed capacitor comprises a capacitor body in a microelectromechanical system (MEMS) structure. The capacitor body has a first plate with a fractal shape separated by a horizontal distance from a second plate with a fractal shape. The first plate and the second plate are within the same plane. Such a fractal fixed capacitor further comprises a substrate above which the capacitor body is positioned.

Enhancement of switching speed of BiFeO3 capacitors by magnetic fields

Directory of Open Access Journals (Sweden)

E. J. Guo

2014-09-01

Full Text Available The effect of a magnetic field on the ferroelectric switching kinetics of BiFeO3 (BFO capacitors with La0.8Ca0.2MnO3 (LCMO bottom electrode and Pt top contact has been investigated. We find a strong dependence of the remnant polarization and coercive field on the magnetic field. The switching time can be systematically tuned by magnetic field and reaches a tenfold reduction around the Curie temperature of LCMO at 4 T. We attribute this behavior to the splitting of the voltage drops across the BFO film and the LCMO bottom electrode, which can be strongly influenced by an external magnetic field due to the magnetoresistance. Further experiments on the BFO capacitors with SrRuO3 bottom electrodes show little magnetic field dependence of ferroelectric switching confirming our interpretation. Our results provide an efficient route to control the ferroelectric switching speed through the magnetic field, implying potential application in multifunctional devices.

Switched-capacitor isolated LED driver

Science.gov (United States)

Sanders, Seth R.; Kline, Mitchell

2016-03-22

A switched-capacitor voltage converter which is particularly well-suited for receiving a line voltage from which to drive current through a series of light emitting diodes (LEDs). Input voltage is rectified in a multi-level rectifier network having switched capacitors in an ascending-bank configuration for passing voltages in uniform steps between zero volts up to full received voltage V.sub.DC. A regulator section, operating on V.sub.DC, comprises switched-capacitor stages of H-bridge switching and flying capacitors. A current controlled oscillator drives the states of the switched-capacitor stages and changes its frequency to maintain a constant current to the load. Embodiments are described for isolating the load from the mains, utilizing an LC tank circuit or a multi-primary-winding transformer.

Fractal Structures For Mems Variable Capacitors

KAUST Repository

Elshurafa, Amro M.

2014-08-28

In accordance with the present disclosure, one embodiment of a fractal variable capacitor comprises a capacitor body in a microelectromechanical system (MEMS) structure, wherein the capacitor body has an upper first metal plate with a fractal shape separated by a vertical distance from a lower first metal plate with a complementary fractal shape; and a substrate above which the capacitor body is suspended.

Capacitor Voltages Measurement and Balancing in Flying Capacitor Multilevel Converters Utilizing a Single Voltage Sensor

DEFF Research Database (Denmark)

Farivar, Glen; Ghias, Amer M. Y. M.; Hredzak, Branislav

2017-01-01

This paper proposes a new method for measuring capacitor voltages in multilevel flying capacitor (FC) converters that requires only one voltage sensor per phase leg. Multiple dc voltage sensors traditionally used to measure the capacitor voltages are replaced with a single voltage sensor at the ac...... side of the phase leg. The proposed method is subsequently used to balance the capacitor voltages using only the measured ac voltage. The operation of the proposed measurement and balancing method is independent of the number of the converter levels. Experimental results presented for a five-level FC...

Super miniaturization of film capacitor dielectrics

Science.gov (United States)

Lavene, B.

1981-01-01

The alignment of the stable electrical characteristics of film capacitors in the physical dimensions of ceramic and tantalum capacitors are discussed. The reliability of polycarbonate and mylar capacitors are described with respect to their compatibility with military specifications. Graphic illustrations are presented which show electrical and physical comparisons of film, ceramic, and tantalum capacitors. The major focus is on volumetric efficiency, weight reduction, and electrical stability.

Performance Analysis of Regenerative Braking in Permanent Magnet Synchronous Motor Drives

Directory of Open Access Journals (Sweden)

Andrew Adib

2018-02-01

Full Text Available This paper describes the design and analysis of a regenerative braking system for a permanent magnet synchronous motor (PMSM drive for electric vehicle (EV applications. First studied is the principle for electric braking control of a PMSM motor under field-oriented control (FOC. Next, the maximum braking torque in the regeneration mode as well as the braking torque for the maximum regeneration power, respectively, are deduced. Additionally, an optimum switching scheme for the inverter is developed with the objective of maximizing energy recovery during regenerative braking to the DC-bus capacitor. The integration of an ultra-capacitor module with the battery allows for the efficient and high power transfer under regenerative braking. It was important to manage the power flow to the DC-bus as this is a key issue that affects the efficiency of the overall system. Finally, the amounts of braking energy that can be recovered, and the efficiency with which it can be returned to the battery/ultra-capacitor, is analyzed for a PMSM coupled with a DC motor as the load. The results of the analysis are validated through experimentation.

M-Split: A Graphical User Interface to Analyze Multilayered Anisotropy from Shear Wave Splitting

Science.gov (United States)

Abgarmi, Bizhan; Ozacar, A. Arda

2017-04-01

Shear wave splitting analysis are commonly used to infer deep anisotropic structure. For simple cases, obtained delay times and fast-axis orientations are averaged from reliable results to define anisotropy beneath recording seismic stations. However, splitting parameters show systematic variations with back azimuth in the presence of complex anisotropy and cannot be represented by average time delay and fast axis orientation. Previous researchers had identified anisotropic complexities at different tectonic settings and applied various approaches to model them. Most commonly, such complexities are modeled by using multiple anisotropic layers with priori constraints from geologic data. In this study, a graphical user interface called M-Split is developed to easily process and model multilayered anisotropy with capabilities to properly address the inherited non-uniqueness. M-Split program runs user defined grid searches through the model parameter space for two-layer anisotropy using formulation of Silver and Savage (1994) and creates sensitivity contour plots to locate local maximas and analyze all possible models with parameter tradeoffs. In order to minimize model ambiguity and identify the robust model parameters, various misfit calculation procedures are also developed and embedded to M-Split which can be used depending on the quality of the observations and their back-azimuthal coverage. Case studies carried out to evaluate the reliability of the program using real noisy data and for this purpose stations from two different networks are utilized. First seismic network is the Kandilli Observatory and Earthquake research institute (KOERI) which includes long term running permanent stations and second network comprises seismic stations deployed temporary as part of the "Continental Dynamics-Central Anatolian Tectonics (CD-CAT)" project funded by NSF. It is also worth to note that M-Split is designed as open source program which can be modified by users for

Fractal Structures For Mems Variable Capacitors

KAUST Repository

Elshurafa, Amro M.; Radwan, Ahmed Gomaa Ahmed; Emira, Ahmed A.; Salama, Khaled N.

2014-01-01

In accordance with the present disclosure, one embodiment of a fractal variable capacitor comprises a capacitor body in a microelectromechanical system (MEMS) structure, wherein the capacitor body has an upper first metal plate with a fractal shape

Faraday Rotator 5 kV Capacitor Bank

International Nuclear Information System (INIS)

Fetterman, C.C.

1975-01-01

A Faraday rotator 5 kV capacitor bank is a pulsed output power supply used to energize Faraday rotators for optical isolation in the ''LLL kJ Glass Laser System.'' Each supply contains either one, two or three parallel 240 μF storage capacitors depending on the size of the isolator used. Generally, the ''A*''(216 μH) isolator is energized with one capacitor, the ''A''(116 μH) isolator uses two capacitors and the ''B''(87 μH) isolator requires three capacitors. All models of isolators have been tested with four capacitors under maximum voltage and 25 feet of RG-217 cable with no hazardous effects. Except for the number of capacitors in each unit, the supplies are otherwise physically identical

Ferroelectric Fractional-Order Capacitors

KAUST Repository

Agambayev, Agamyrat; Patole, Shashikant P.; Farhat, Mohamed; Elwakil, Ahmed; Bagci, Hakan; Salama, Khaled N.

2017-01-01

Poly(vinylidene fluoride)-based polymers and their blends are used to fabricate electrostatic fractional-order capacitors. This simple but effective method allows us to precisely tune the constant phase angle of the resulting fractional-order capacitor by changing the blend composition. Additionally, we have derived an empirical relation between the ratio of the blend constituents and the constant phase angle to facilitate the design of a fractional order capacitor with a desired constant phase angle. The structural composition of the fabricated blends is investigated using Fourier transform infrared spectroscopy and X-ray diffraction techniques.

Ferroelectric Fractional-Order Capacitors

KAUST Repository

Agambayev, Agamyrat

2017-07-25

Poly(vinylidene fluoride)-based polymers and their blends are used to fabricate electrostatic fractional-order capacitors. This simple but effective method allows us to precisely tune the constant phase angle of the resulting fractional-order capacitor by changing the blend composition. Additionally, we have derived an empirical relation between the ratio of the blend constituents and the constant phase angle to facilitate the design of a fractional order capacitor with a desired constant phase angle. The structural composition of the fabricated blends is investigated using Fourier transform infrared spectroscopy and X-ray diffraction techniques.

SplitRacer - a new Semi-Automatic Tool to Quantify And Interpret Teleseismic Shear-Wave Splitting

Science.gov (United States)

Reiss, M. C.; Rumpker, G.

2017-12-01

We have developed a semi-automatic, MATLAB-based GUI to combine standard seismological tasks such as the analysis and interpretation of teleseismic shear-wave splitting. Shear-wave splitting analysis is widely used to infer seismic anisotropy, which can be interpreted in terms of lattice-preferred orientation of mantle minerals, shape-preferred orientation caused by fluid-filled cracks or alternating layers. Seismic anisotropy provides a unique link between directly observable surface structures and the more elusive dynamic processes in the mantle below. Thus, resolving the seismic anisotropy of the lithosphere/asthenosphere is of particular importance for geodynamic modeling and interpretations. The increasing number of seismic stations from temporary experiments and permanent installations creates a new basis for comprehensive studies of seismic anisotropy world-wide. However, the increasingly large data sets pose new challenges for the rapid and reliably analysis of teleseismic waveforms and for the interpretation of the measurements. Well-established routines and programs are available but are often impractical for analyzing large data sets from hundreds of stations. Additionally, shear wave splitting results are seldom evaluated using the same well-defined quality criteria which may complicate comparison with results from different studies. SplitRacer has been designed to overcome these challenges by incorporation of the following processing steps: i) downloading of waveform data from multiple stations in mseed-format using FDSNWS tools; ii) automated initial screening and categorizing of XKS-waveforms using a pre-set SNR-threshold; iii) particle-motion analysis of selected phases at longer periods to detect and correct for sensor misalignment; iv) splitting analysis of selected phases based on transverse-energy minimization for multiple, randomly-selected, relevant time windows; v) one and two-layer joint-splitting analysis for all phases at one station by

Direct Mismatch Characterization of femto-Farad Capacitors

KAUST Repository

Omran, Hesham

2015-08-17

Reducing the capacitance of programmable capacitor arrays, commonly used in analog integrated circuits, is necessary for low-energy applications. However, limited mismatch data is available for small capacitors. We report mismatch measurement for a 2fF poly-insulator-poly (PIP) capacitor, which is the smallest reported PIP capacitor to the best of the authors’ knowledge. Instead of using complicated custom onchip circuitry, direct mismatch measurement is demonstrated and verified using Monte Carlo Simulations and experimental measurements. Capacitive test structures composed of 9 bit programmable capacitor arrays (PCAs) are implemented in a low-cost 0:35m CMOS process. Measured data is compared to mismatch of large PIP capacitors, theoretical models, and recently published data. Measurement results indicate an estimated average relative standard deviation of 0.43% for the 2fF unit capacitor, which is better than the reported mismatch of metal-oxide-metal (MOM) fringing capacitors implemented in an advanced 32nm CMOS process.

Direct Mismatch Characterization of femto-Farad Capacitors

KAUST Repository

Omran, Hesham; Elafandy, Rami T.; Arsalan, Muhammad; Salama, Khaled N.

2015-01-01

Reducing the capacitance of programmable capacitor arrays, commonly used in analog integrated circuits, is necessary for low-energy applications. However, limited mismatch data is available for small capacitors. We report mismatch measurement for a 2fF poly-insulator-poly (PIP) capacitor, which is the smallest reported PIP capacitor to the best of the authors’ knowledge. Instead of using complicated custom onchip circuitry, direct mismatch measurement is demonstrated and verified using Monte Carlo Simulations and experimental measurements. Capacitive test structures composed of 9 􀀀 bit programmable capacitor arrays (PCAs) are implemented in a low-cost 0:35m CMOS process. Measured data is compared to mismatch of large PIP capacitors, theoretical models, and recently published data. Measurement results indicate an estimated average relative standard deviation of 0.43% for the 2fF unit capacitor, which is better than the reported mismatch of metal-oxide-metal (MOM) fringing capacitors implemented in an advanced 32nm CMOS process.

Electromechanical capacitor for energy transfer

International Nuclear Information System (INIS)

Carroll, T.A.; Chowdhuri, P.; Marshall, J.

1983-01-01

Inductive energy transfer between two magnets can be achieved with almost 100% efficiency with a transfer capacitor. However, the bulk and cost will be high, and reliability low if conventional capacitors are used. A homopolar machine, used as a capacitor, will be compact and economical. A homopolar machine was designed with counter-rotating copper disks completely immersed in a liquid metal (NaK-78) to work as a pulse capacitor. Absence of solid-brush collectors minimized wear and frictional losses. Wetting of the copper disks throughout the periphery by the liquid metal minimized the resistive losses at the collector interface. A liquid-metal collector would, however, introduce hydrodynamic and magnetohydrodynamic losses. The selected liquid metal, e.g., NaK-78 will produce the lowest of such losses among the available liquid metals. An electromechanical capacitor of this design was tested at various dc magnetic fields. Its measured capacitance was about 100 farads at a dc magnetic field of 1.15 tesla

Development of 2.45GHz compact ECR ion sources with permanent magnets

International Nuclear Information System (INIS)

Tojyo, E.; Ohshiro, Y.; Oyaizu, M.; Shirakabe, Y.

1993-05-01

Two kinds of new compact ECR ion sources have been developed by use of permanent magnets only, for the purpose of acceleration tests of the 25.5MHz INS split coaxial RFQ linac and the 50MHz one. Confined magnetic fields of sources are constructed by permanent magnets only. In this paper design parameters, structures, magnetic field distributions and extracted beam properties of these sources are described briefly. (author)

A SAR-ADC using unit bridge capacitor and with calibration for the front-end electronics of PET imaging

Energy Technology Data Exchange (ETDEWEB)

Liu, Wei [School of Computer Science and Engineering, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China); Wei, Tingcun, E-mail: weitc@nwpu.edu.cn [School of Computer Science and Engineering, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China); Li, Bo; Yang, Lifeng; Xue, Feifei [School of Computer Science and Engineering, Northwestern Polytechnical University, Xi' an 710072, Shaanxi (China); Hu, Yongcai [Institut Pluridisciplinaire Hubert CURIEN, Strasbourg (France)

2016-05-11

This paper presents a 12-bit 1 MS/s successive approximation register-analog to digital converter (SAR-ADC) for the 32-channel front-end electronics of CZT-based PET imaging system. To reduce the capacitance mismatch, instead of the fractional capacitor, the unit capacitor is used as the bridge capacitor in the split-capacitor digital to analog converter (DAC) circuit. In addition, in order to eliminate the periodical DNL errors of −1 LSB which often exists in the SAR-ADC using the charge-redistributed DAC, a calibration algorithm is proposed and verified by the experiments. The proposed 12-bit 1 MS/s SAR-ADC is designed and implemented using a 0.35 μm CMOS technology, it occupies only an active area of 986×956 μm{sup 2}. The measurement results show that, at the power supply of 3.3/5.0 V and the sampling rate of 1 MS/s, the ADC with calibration has a signal-to-noise-and-distortion ratio (SINAD) of 67.98 dB, the power dissipation of 5 mW, and a figure of merit (FOM) of 2.44 pJ/conv.-step. This ADC is with the features of high accuracy, low power and small layout area, it is especially suitable to the one-chip integration of the front-end readout electronics.

Evaluation of Polymer Hermetically Sealed Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander A.

2014-01-01

Polymer cathode tantalum capacitors have lower ESR (equivalent series resistance) compared to other types of tantalum capacitors and for this reason have gained popularity in the electronics design community. Their use allows improved performance of power supply systems along with substantial reduction of size and weight of the components used. However, these parts have poor thermal stability and can degrade in humid environments. Polymer hermetically sealed (PHS) capacitors avoid problems related to environmental degradation of molded case parts and can potentially replace current wet and solid hermetically sealed capacitors. In this work, PHS capacitors manufactured per DLA LAM DWG#13030 are evaluated for space applications. Several lots of capacitors manufactured over period from 2010 to 2014 were tested for the consistency of performance, electrical and thermal characteristics, highly accelerated life testing, and robustness under reverse bias and random vibration conditions. Special attention was given to analysis of leakage currents and the effect of long-term high temperature storage on capacitors in as is condition and after hermeticity loss. The results show that PHS capacitors might be especially effective for low-temperature applications or for system requiring a cold start-up. Additional screening and qualification testing have been recommended to assure the necessary quality of capacitors for space projects.

Polyvinylidene fluoride film as a capacitor dielectric

Science.gov (United States)

Dematos, H. V.

1981-01-01

Thin strips of polyvinylidene fluoride film (PVDF) with vacuum deposited electrodes were made into capacitors by conventional winding and fabrication techniques. These devices were used to identify and evaluate the performance characteristics offered by the PVDF in metallized film capacitors. Variations in capacitor parameters with temperature and frequence were evaluated and compared with other dielectric films. Their impact on capacitor applications is discussed.

Mutual capacitor and its applications

Directory of Open Access Journals (Sweden)

Chun Li

2014-06-01

Full Text Available This study presents a new ac circuit element – the mutual capacitor, being a dual of the mutual inductor, which is also a new ac transformer. This element is characteristic of the mutual-capacitance coupling of a multi-capacitance system. A unity-coupled mutual capacitor works as an ideal current or voltage transformer, and incidentally acts as waveform separating when inductor employed or waveform converting from square-wave to quasi-sine or waveform filtering, between ports. As a transformer, the mutual capacitor is easy to design, easy for heat cooling, more accurate for current or voltage transformation, dissipating less energy as well as saving materials, suitable for high-power and high-voltage applications. Experiments to demonstrate performances of unity-coupled mutual capacitors are also given.

High density energy storage capacitor

International Nuclear Information System (INIS)

Whitham, K.; Howland, M.M.; Hutzler, J.R.

1979-01-01

The Nova laser system will use 130 MJ of capacitive energy storage and have a peak power capability of 250,000 MW. This capacitor bank is a significant portion of the laser cost and requires a large portion of the physical facilities. In order to reduce the cost and volume required by the bank, the Laser Fusion Program funded contracts with three energy storage capacitor producers: Aerovox, G.E., and Maxwell Laboratories, to develop higher energy density, lower cost energy storage capacitors. This paper describes the designs which resulted from the Aerovox development contract, and specifically addresses the design and initial life testing of a 12.5 kJ, 22 kV capacitor with a density of 4.2 J/in 3 and a projected cost in the range of 5 cents per joule

Physical and Electrical Characterization of Polymer Aluminum Capacitors

Science.gov (United States)

Liu, David; Sampson, Michael J.

2010-01-01

Polymer aluminum capacitors from several manufacturers with various combinations of capacitance, rated voltage, and ESR values were physically examined and electrically characterized. The physical construction analysis of the capacitors revealed three different capacitor structures, i.e., traditional wound, stacked, and laminated. Electrical characterization results of polymer aluminum capacitors are reported for frequency-domain dielectric response at various temperatures, surge breakdown voltage, and other dielectric properties. The structure-property relations in polymer aluminum capacitors are discussed.

Physical and Electrical Characterization of Aluminum Polymer Capacitors

Science.gov (United States)

Liu, David; Sampson, Michael J.

2010-01-01

Polymer aluminum capacitors from several manufacturers with various combinations of capacitance, rated voltage, and ESR values were physically examined and electrically characterized. The physical construction analysis of the capacitors revealed three different capacitor structures, i.e., traditional wound, stacked, and laminated. Electrical characterization results of polymer aluminum capacitors are reported for frequency-domain dielectric response at various temperatures, surge breakdown voltage, and other dielectric properties. The structure-property relations in polymer aluminum capacitors are discussed.

Nanostructured Electrode Materials for Electrochemical Capacitor Applications.

Science.gov (United States)

Choi, Hojin; Yoon, Hyeonseok

2015-06-02

The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013). Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead.

SplitRacer - a semi-automatic tool for the analysis and interpretation of teleseismic shear-wave splitting

Science.gov (United States)

Reiss, Miriam Christina; Rümpker, Georg

2017-04-01

We present a semi-automatic, graphical user interface tool for the analysis and interpretation of teleseismic shear-wave splitting in MATLAB. Shear wave splitting analysis is a standard tool to infer seismic anisotropy, which is often interpreted as due to lattice-preferred orientation of e.g. mantle minerals or shape-preferred orientation caused by cracks or alternating layers in the lithosphere and hence provides a direct link to the earth's kinematic processes. The increasing number of permanent stations and temporary experiments result in comprehensive studies of seismic anisotropy world-wide. Their successive comparison with a growing number of global models of mantle flow further advances our understanding the earth's interior. However, increasingly large data sets pose the inevitable question as to how to process them. Well-established routines and programs are accurate but often slow and impractical for analyzing a large amount of data. Additionally, shear wave splitting results are seldom evaluated using the same quality criteria which complicates a straight-forward comparison. SplitRacer consists of several processing steps: i) download of data per FDSNWS, ii) direct reading of miniSEED-files and an initial screening and categorizing of XKS-waveforms using a pre-set SNR-threshold. iii) an analysis of the particle motion of selected phases and successive correction of the sensor miss-alignment based on the long-axis of the particle motion. iv) splitting analysis of selected events: seismograms are first rotated into radial and transverse components, then the energy-minimization method is applied, which provides the polarization and delay time of the phase. To estimate errors, the analysis is done for different randomly-chosen time windows. v) joint-splitting analysis for all events for one station, where the energy content of all phases is inverted simultaneously. This allows to decrease the influence of noise and to increase robustness of the measurement

Modeling of Self-Excited Isolated Permanent Magnet Induction Generator Using Iterative Numerical Method

Directory of Open Access Journals (Sweden)

Mohamed Mostafa R.

2016-01-01

Full Text Available Self-Excited Permanent Magnet Induction Generator (PMIG is commonly used in wind energy generation systems. The difficulty of Self-Excited Permanent Magnet Induction Generator (SEPMIG modeling is the circuit parameters of the generator vary at each load conditions due to the a change in the frequency and stator voltage. The paper introduces a new modeling for SEPMIG using Gauss-sidle relaxation method. The SEPMIG characteristics using the proposed method are studied at different load conditions according to the wind speed variation, load impedance changes and different shunted capacitor values. The system modeling is investigated due to the magnetizing current variation, the efficiency variation, the power variation and power factor variation. The proposed modeling system satisfies high degree of simplicity and accuracy.

A Simple, Successful Capacitor Lab

Science.gov (United States)

Ennis, William

2011-01-01

Capacitors are a fundamental component of modern electronics. They appear in myriad devices and in an enormous range of sizes. Although our students are taught the function and analysis of capacitors, few have the opportunity to use them in our labs.

Nanostructured Electrode Materials for Electrochemical Capacitor Applications

Directory of Open Access Journals (Sweden)

Hojin Choi

2015-06-01

Full Text Available The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013. Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead.

Capacitor performance limitations in high power converter applications

DEFF Research Database (Denmark)

El-Khatib, Walid Ziad; Holbøll, Joachim; Rasmussen, Tonny Wederberg

2013-01-01

High voltage low inductance capacitors are used in converters as HVDC-links, snubber circuits and sub model (MMC) capacitances. They facilitate the possibility of large peak currents under high frequent or transient voltage applications. On the other hand, using capacitors with larger equivalent...... series inductances include the risk of transient overvoltages, with a negative effect on life time and reliability of the capacitors. These allowable limits of such current and voltage peaks are decided by the ability of the converter components, including the capacitors, to withstand them over...... the expected life time. In this paper results are described from investigations on the electrical environment of these capacitors, including all the conditions they would be exposed to, thereby trying to find the tradeoffs needed to find a suitable capacitor. Different types of capacitors with the same voltage...

Electrical characterization of thin film ferroelectric capacitors

NARCIS (Netherlands)

Tiggelman, M.P.J.; Reimann, K.; Klee, M.; Beelen, D.; Keur, W.; Schmitz, Jurriaan; Hueting, Raymond Josephus Engelbart

2006-01-01

Tunable capacitors can be used to facilitate the reduction of components in wireless technologies. The tunability of the capacitors is caused by the sensitivity of the relative dielectric constant to a change in polarization with electric field. Thin film ferroelectric MIM capacitors on silicon

Physics of failure based analysis of aluminium electrolytic capacitor

International Nuclear Information System (INIS)

Sahoo, Satya Ranjan; Behera, S.K.; Kumar, Sachin; Varde, P.V.; Ravi Kumar, G.

2016-01-01

Electrolytic capacitors are one of the important devices in various power electronic systems, such as motor drives, uninterruptible power supply, electric vehicles and dc power supply. Electrolytic capacitors are also the integral part of many other electronic devices. One of the primary function of electrolytic capacitors is the smoothing of voltage ripple and storing electrical energy. However, the electrolytic capacitor has the shortest lifespan of components in power electronics. Past experiences show that electrolytic capacitor tends to degrade and fail faster under high electrical or thermal stress conditions during operations. The primary failure mechanism of an electrolytic capacitor is the evaporation of the electrolyte due to electrical or thermal overstress. This leads to the drift in the values of two important parameters-capacitance and equivalent series resistance (ESR) of the electrolytic capacitor. An attempt has been made to age the electrolytic capacitor and validate the results. The overall goal is to derive the accurate degradation model of the electrolytic capacitor. (author)

Integrated capacitor arrangement for ultrahigh capacitance values

NARCIS (Netherlands)

Roozeboom, F.; Klootwijk, J.H.; Kemmeren, A.L.A.M.; Reefman, D.; Verhoeven, J.F.C.M.

2011-01-01

An electronic device includes at least one trench capacitor that can also take the form of an inverse structure, a pillar capacitor. An alternating layer sequence of at least two dielectric layers and at least two electrically conductive layers is provided in the trench capacitor or on the pillar

Capacitor requirements for controlled thermonuclear experiments and reactors

International Nuclear Information System (INIS)

Boicourt, G.P.; Hoffman, P.S.

1975-01-01

Future controlled thermonuclear experiments as well as controlled thermonuclear reactors will require substantial numbers of capacitors. The demands on these units are likely to be quite severe and quite different from the normal demands placed on either present energy storage capacitors or present power factor correction capacitors. It is unlikely that these two types will suffice for all necessary Controlled Thermonuclear Research (CTR) applications. The types of capacitors required for the various CTR operating conditions are enumerated. Factors that influence the life, cost and operating abilities of these types of capacitors are discussed. The problems of capacitors in a radiation environment are considered. Areas are defined where future research is needed. Some directions that this research should take are suggested. (U.S.)

Capacitor requirements for controlled thermonuclear experiments and reactors

International Nuclear Information System (INIS)

Boicourt, G.P.; Hoffman, P.S.

1975-01-01

Future controlled thermonuclear experiments as well as controlled thermonuclear reactors will require substantial numbers of capacitors. The demands on these units are likely to be quite severe and quite different from the normal demands placed on either present energy storage capacitors or present power factor correction capacitors. It is unlikely that these two types will suffice for all necessary Controlled Thermonuclear Research (CTR) applications. The types of capacitors required for the various CTR operating conditions are enumerated. Factors that influence the life, cost and operating abilities of these types of capacitors are discussed. The problems of capacitors in a radiation environment are considered. Areas are defined where future research is needed. Some directions that this research should take are suggested

Ferroelectric capacitor with reduced imprint

Science.gov (United States)

Evans, Jr., Joseph T.; Warren, William L.; Tuttle, Bruce A.; Dimos, Duane B.; Pike, Gordon E.

1997-01-01

An improved ferroelectric capacitor exhibiting reduced imprint effects in comparison to prior art capacitors. A capacitor according to the present invention includes top and bottom electrodes and a ferroelectric layer sandwiched between the top and bottom electrodes, the ferroelectric layer comprising a perovskite structure of the chemical composition ABO.sub.3 wherein the B-site comprises first and second elements and a dopant element that has an oxidation state greater than +4. The concentration of the dopant is sufficient to reduce shifts in the coercive voltage of the capacitor with time. In the preferred embodiment of the present invention, the ferroelectric element comprises Pb in the A-site, and the first and second elements are Zr and Ti, respectively. The preferred dopant is chosen from the group consisting of Niobium, Tantalum, and Tungsten. In the preferred embodiment of the present invention, the dopant occupies between 1 and 8% of the B-sites.

Suspended graphene variable capacitor

OpenAIRE

AbdelGhany, M.; Mahvash, F.; Mukhopadhyay, M.; Favron, A.; Martel, R.; Siaj, M.; Szkopek, T.

2016-01-01

The tuning of electrical circuit resonance with a variable capacitor, or varactor, finds wide application with the most important being wireless telecommunication. We demonstrate an electromechanical graphene varactor, a variable capacitor wherein the capacitance is tuned by voltage controlled deflection of a dense array of suspended graphene membranes. The low flexural rigidity of graphene monolayers is exploited to achieve low actuation voltage in an ultra-thin structure. Large arrays compr...

Protection of large capacitor banks

International Nuclear Information System (INIS)

Sprott, J.C.; Lovell, T.W.

1982-06-01

Large capacitor banks, as used in many pulsed plasma experiments, are subject to catastrophic failure in the event of a short in the output or in an individual capacitor. Methods are described for protecting such banks to minimize the damage and down-time caused by such a failure

Capacitor discharges, magnetohydrodynamics, X-rays, ultrasonics

CERN Document Server

Früngel, Frank B A

1965-01-01

High Speed Pulse Technology, Volume 1: Capacitor Discharges - Magnetohydrodynamics - X-Rays - Ultrasonics deals with the theoretical and engineering problems that arise in the capacitor discharge technique.This book discusses the characteristics of dielectric material, symmetrical switch tubes with mercury filling, and compensation conductor forms. The transformed discharge for highest current peaks, ignition transformer for internal combustion engines, and X-ray irradiation of subjects in mechanical motion are also elaborated. This text likewise covers the transformed capacitor discharge in w

Method of manufacturing a shapeable short-resistant capacitor

Science.gov (United States)

Taylor, Ralph S.; Myers, John D.; Baney, William J.

2013-04-02

A method that employs a novel combination of conventional fabrication techniques provides a ceramic short-resistant capacitor that is bendable and/or shapeable to provide a multiple layer capacitor that is extremely compact and amenable to desirable geometries. The method allows thinner and more flexible ceramic capacitors to be made. The method includes forming a first thin metal layer on a substrate; depositing a thin, ceramic dielectric layer over the metal layer; depositing a second thin metal layer over the dielectric layer to form a capacitor exhibiting a benign failure mode; and separating the capacitor from the substrate. The method may also include bending the resulting capacitor into a serpentine arrangement with gaps between the layers that allow venting of evaporated electrode material in the event of a benign failure.

Capacitor blocks for linear transformer driver stages.

Science.gov (United States)

Kovalchuk, B M; Kharlov, A V; Kumpyak, E V; Smorudov, G V; Zherlitsyn, A A

2014-01-01

In the Linear Transformer Driver (LTD) technology, the low inductance energy storage components and switches are directly incorporated into the individual cavities (named stages) to generate a fast output voltage pulse, which is added along a vacuum coaxial line like in an inductive voltage adder. LTD stages with air insulation were recently developed, where air is used both as insulation in a primary side of the stages and as working gas in the LTD spark gap switches. A custom designed unit, referred to as a capacitor block, was developed for use as a main structural element of the transformer stages. The capacitor block incorporates two capacitors GA 35426 (40 nF, 100 kV) and multichannel multigap gas switch. Several modifications of the capacitor blocks were developed and tested on the life time and self breakdown probability. Blocks were tested both as separate units and in an assembly of capacitive module, consisting of five capacitor blocks. This paper presents detailed design of capacitor blocks, description of operation regimes, numerical simulation of electric field in the switches, and test results.

Matching Properties of Femtofarad and Sub-Femtofarad MOM Capacitors

KAUST Repository

Omran, Hesham

2016-04-21

Small metal-oxide-metal (MOM) capacitors are essential to energy-efficient mixed-signal integrated circuit design. However, only few reports discuss their matching properties based on large sets of measured data. In this paper, we report matching properties of femtofarad and sub-femtofarad MOM vertical-field parallel-plate capacitors and lateral-field fringing capacitors. We study the effect of both the finger-length and finger-spacing on the mismatch of lateral-field capacitors. In addition, we compare the matching properties and the area efficiency of vertical-field and lateral-field capacitors. We use direct mismatch measurement technique, and we illustrate its feasibility using experimental measurements and Monte Carlo simulations. The test-chips are fabricated in a 0.18 \\\\mutext{m} CMOS process. A large number of test structures is characterized (4800 test structures), which improves the statistical reliability of the extracted mismatch information. Despite conventional wisdom, extensive measurements show that vertical-field and lateral-field MOM capacitors have the same matching properties when the actual capacitor area is considered. Measurements show that the mismatch depends on the capacitor area but not on the spacing; thus, for a given mismatch specification, the lateral-field MOM capacitor can have arbitrarily small capacitance by increasing the spacing between the capacitor fingers, at the expense of increased chip area.

Multilayer ceramic capacitors for pulsed power, high temperature applications

International Nuclear Information System (INIS)

Cygan, S.; McLarney, J.; Prymak, J.; Bohn, P.

1991-01-01

The performance of the multilayer ceramic capacitors (MLC) in high frequency power applications has improved significantly over the last years. One of the possible applications of MLC capacitors is the automotive industry where repetitive discharging of capacitors is required. A 0.25-μF capacitor using NPO dielectric subjected to repetitive discharging with the rate of 700 pulses per second, magnitude of 600-V and 195-A peak currents showed no degradation in performance at 298 K or 398 K even after 1 billion discharge cycles. Less than a 5-K temperature rise was observed under these conditions. The most exciting, newly emerging utilization for MLC capacitors, however, might be the high temperature application (up to 473 K for underhood utilization), where ceramic capacitors with higher volumetric efficiency as compared to glass or polymer type capacitors prove very superior. Moreover ceramic capacitors, which next to glass capacitors exhibit the greatest radiation resistance among all insulating materials (Hanks and Hamman 1971), might also be best suited in the future for high temperature operation in space environment. The pulsed power performance of the 0.25-μF NPO capacitor was evaluated under repetitive discharge conditions (200 V, 700 pps) at high temperature, 473 K, and the results are presented in this paper

Matching Properties of Femtofarad and Sub-Femtofarad MOM Capacitors

KAUST Repository

Omran, Hesham; Alahmadi, Hamzah; Salama, Khaled N.

2016-01-01

Small metal-oxide-metal (MOM) capacitors are essential to energy-efficient mixed-signal integrated circuit design. However, only few reports discuss their matching properties based on large sets of measured data. In this paper, we report matching properties of femtofarad and sub-femtofarad MOM vertical-field parallel-plate capacitors and lateral-field fringing capacitors. We study the effect of both the finger-length and finger-spacing on the mismatch of lateral-field capacitors. In addition, we compare the matching properties and the area efficiency of vertical-field and lateral-field capacitors. We use direct mismatch measurement technique, and we illustrate its feasibility using experimental measurements and Monte Carlo simulations. The test-chips are fabricated in a 0.18 \\mutext{m} CMOS process. A large number of test structures is characterized (4800 test structures), which improves the statistical reliability of the extracted mismatch information. Despite conventional wisdom, extensive measurements show that vertical-field and lateral-field MOM capacitors have the same matching properties when the actual capacitor area is considered. Measurements show that the mismatch depends on the capacitor area but not on the spacing; thus, for a given mismatch specification, the lateral-field MOM capacitor can have arbitrarily small capacitance by increasing the spacing between the capacitor fingers, at the expense of increased chip area.

New Temperature-Insensitive Electronically-Tunable Grounded Capacitor Simulator

OpenAIRE

Abuelma'atti, Muhammad Taher; Khan, Muhammad Haroon

1996-01-01

A new circuit for simulating a grounded capacitor is presented. The circuit uses one operationalamplifier (OA), three operational-transconductance amplifiers (OTAs), and one capacitor. The realized capacitor is temperature-insensitive and electronically tunable. Experimental results are included.

Evaluation of Case Size 0603 BME Ceramic Capacitors

Science.gov (United States)

Teverovsky, Alexander A.

2015-01-01

High volumetric efficiency of commercial base metal electrode (BME) ceramic capacitors allows for a substantial reduction of weight and sizes of the parts compared to currently used military grade precious metal electrode (PME) capacitors. Insertion of BME capacitors in space applications requires a thorough analysis of their performance and reliability. In this work, six types of cases size 0603 BME capacitors from three vendors have been evaluated. Three types of multilayer ceramic capacitors (MLCCs) were designed for automotive industry and three types for general purposes. Leakage currents in the capacitors have been measured in a wide range of voltages and temperatures, and measurements of breakdown voltages (VBR) have been used to assess the proportion and severity of defects in the parts. The effect of soldering-related thermal shock stresses was evaluated by analysis of distributions of VBR for parts in 'as is' condition and after terminal solder dip testing at 350 C. Highly Accelerated Life Testing (HALT) at different temperatures was used to assess the activation energy of degradation of leakage currents and predict behavior of the parts at life test and normal operating conditions. To address issues related to rework and manual soldering, capacitors were soldered onto different substrates at different soldering conditions. The results show that contrary to a common assumption that large-size capacitors are mostly vulnerable to soldering stresses, cracking in small size capacitors does happen unless special measures are taken during assembly processes.

Electric field mapping inside metallized film capacitors

DEFF Research Database (Denmark)

Nielsen, Dennis Achton; Popok, Vladimir; Pedersen, Kjeld

2015-01-01

(s) they suffered from accelerated testing. We have prepared film capacitors for analysis by micro-sectioning and verified the quality of the preparation procedure using optical and atomic force microscopy. The potential distribution in the layer structure (alternating 7 µm thick dielectric and 50-100 nm thick...... and durability and serves as verification that failure- and degradation mechanisms remain the same at different stress levels during accelerated testing. In this work we have used Kelvin probe force microscopy (KPFM) to analyze metallized film capacitors with the purpose of determining the degradation mechanism...... metal) of a new capacitor was used as reference. KPFM measurements on the degraded capacitors showed a change in contact potential difference from -0.61V on the reference capacitor to 3.2V on the degraded ones, indicating that corrosion of the metallization had happened. Studies also showed that some...

Method of manufacturing a capacitor on a nanowire and integrated circuit having such a capacitor

NARCIS (Netherlands)

2009-01-01

A method of manufacturing a capacitor on a wafer, and an IC comprising such a capacitor is disclosed. The method comprises forming a plurality of vertical structures (140) each having a sub-micron thickness on the wafer; and growing a metal-insulator-metal (MIM) stack (150) over the plurality of

Protection of MOS capacitors during anodic bonding

Science.gov (United States)

Schjølberg-Henriksen, K.; Plaza, J. A.; Rafí, J. M.; Esteve, J.; Campabadal, F.; Santander, J.; Jensen, G. U.; Hanneborg, A.

2002-07-01

We have investigated the electrical damage by anodic bonding on CMOS-quality gate oxide and methods to prevent this damage. n-type and p-type MOS capacitors were characterized by quasi-static and high-frequency CV-curves before and after anodic bonding. Capacitors that were bonded to a Pyrex wafer with 10 μm deep cavities enclosing the capacitors exhibited increased leakage current and interface trap density after bonding. Two different methods were successful in protecting the capacitors from such damage. Our first approach was to increase the cavity depth from 10 μm to 50 μm, thus reducing the electric field across the gate oxide during bonding from approximately 2 × 105 V cm-1 to 4 × 104 V cm-1. The second protection method was to coat the inside of a 10 μm deep Pyrex glass cavity with aluminium, forming a Faraday cage that removed the electric field across the cavity during anodic bonding. Both methods resulted in capacitors with decreased interface trap density and unchanged leakage current after bonding. No change in effective oxide charge or mobile ion contamination was observed on any of the capacitors in the study.

High power density capacitor and method of fabrication

Science.gov (United States)

Tuncer, Enis

2012-11-20

A ductile preform for making a drawn capacitor includes a plurality of electrically insulating, ductile insulator plates and a plurality of electrically conductive, ductile capacitor plates. Each insulator plate is stacked vertically on a respective capacitor plate and each capacitor plate is stacked on a corresponding insulator plate in alignment with only one edge so that other edges are not in alignment and so that each insulator plate extends beyond the other edges. One or more electrically insulating, ductile spacers are disposed in horizontal alignment with each capacitor plate along the other edges and the pattern is repeated so that alternating capacitor plates are stacked on alternating opposite edges of the insulator plates. A final insulator plate is positioned at an extremity of the preform. The preform may then be drawn to fuse the components and decrease the dimensions of the preform that are perpendicular to the direction of the draw.

Super capacitor modeling with artificial neural network (ANN)

Energy Technology Data Exchange (ETDEWEB)

Marie-Francoise, J.N.; Gualous, H.; Berthon, A. [Universite de Franche-Comte, Lab. en Electronique, Electrotechnique et Systemes (L2ES), UTBM, INRETS (LRE T31) 90 - Belfort (France)

2004-07-01

This paper presents super-capacitors modeling using Artificial Neural Network (ANN). The principle consists on a black box nonlinear multiple inputs single output (MISO) model. The system inputs are temperature and current, the output is the super-capacitor voltage. The learning and the validation of the ANN model from experimental charge and discharge of super-capacitor establish the relationship between inputs and output. The learning and the validation of the ANN model use experimental results of 2700 F, 3700 F and a super-capacitor pack. Once the network is trained, the ANN model can predict the super-capacitor behaviour with temperature variations. The update parameters of the ANN model are performed thanks to Levenberg-Marquardt method in order to minimize the error between the output of the system and the predicted output. The obtained results with the ANN model of super-capacitor and experimental ones are in good agreement. (authors)

Evaluation of Commercial Automotive-Grade BME Capacitors

Science.gov (United States)

Liu, Donhang

2014-01-01

Three Ni-BaTiO3 ceramic capacitor lots with the same specification (chip size, capacitance, and rated voltage) and the same reliability level, made by three different manufacturers, were degraded using highly accelerated life stress testing (HALST) with the same temperature and applied voltage conditions. The reliability, as characterized by mean time to failure (MTTF), differed by more than one order of magnitude among the capacitor lots. A theoretical model based on the existence of depletion layers at grain boundaries and the entrapment of oxygen vacancies has been proposed to explain the MTTF difference among these BME capacitors. It is the conclusion of this model that reliability will not be improved simply by increasing the insulation resistance of a BME capacitor. Indeed, Ni-BaTiO3 ceramic capacitors with a smaller degradation rate constant K will always give rise to a longer reliability life.

2014 NEPP Tasks Update for Ceramic and Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander A.

2014-01-01

Presentation describes recent development in research on MnO2, wet, and polymer tantalum capacitors. Low-voltage failures in multilayer ceramic capacitors and techniques to reveal precious metal electrode (PME) and base metal electrode (BME) capacitors with cracks are discussed. A voltage breakdown technique is suggested to select high quality low-voltage BME ceramic capacitors.

Physicochemical assessment criteria for high-voltage pulse capacitors

Energy Technology Data Exchange (ETDEWEB)

Darian, L. A., E-mail: LDarian@rambler.ru; Lam, L. Kh. [National Research University, Moscow Power Engineering Institute (Russian Federation)

2016-12-15

In the paper, the applicability of decomposition products of internal insulation of high-voltage pulse capacitors is considered (aging is the reason for decomposition products of internal insulation). Decomposition products of internal insulation of high-voltage pulse capacitors can be used to evaluate their quality when in operation and in service. There have been three generations of markers of aging of insulation as in the case with power transformers. The area of applicability of markers of aging of insulation for power transformers has been studied and the area can be extended to high-voltage pulse capacitors. The research reveals that there is a correlation between the components and quantities of markers of aging of the first generation (gaseous decomposition products of insulation) dissolved in insulating liquid and the remaining life of high-voltage pulse capacitors. The application of markers of aging to evaluate the remaining service life of high-voltage pulse capacitor is a promising direction of research, because the design of high-voltage pulse capacitors keeps stability of markers of aging of insulation in high-voltage pulse capacitors. It is necessary to continue gathering statistical data concerning development of markers of aging of the first generation. One should also carry out research aimed at estimation of the remaining life of capacitors using markers of the second and the third generation.

Physicochemical assessment criteria for high-voltage pulse capacitors

International Nuclear Information System (INIS)

Darian, L. A.; Lam, L. Kh.

2016-01-01

In the paper, the applicability of decomposition products of internal insulation of high-voltage pulse capacitors is considered (aging is the reason for decomposition products of internal insulation). Decomposition products of internal insulation of high-voltage pulse capacitors can be used to evaluate their quality when in operation and in service. There have been three generations of markers of aging of insulation as in the case with power transformers. The area of applicability of markers of aging of insulation for power transformers has been studied and the area can be extended to high-voltage pulse capacitors. The research reveals that there is a correlation between the components and quantities of markers of aging of the first generation (gaseous decomposition products of insulation) dissolved in insulating liquid and the remaining life of high-voltage pulse capacitors. The application of markers of aging to evaluate the remaining service life of high-voltage pulse capacitor is a promising direction of research, because the design of high-voltage pulse capacitors keeps stability of markers of aging of insulation in high-voltage pulse capacitors. It is necessary to continue gathering statistical data concerning development of markers of aging of the first generation. One should also carry out research aimed at estimation of the remaining life of capacitors using markers of the second and the third generation.

A compact 100 kV high voltage glycol capacitor.

Science.gov (United States)

Wang, Langning; Liu, Jinliang; Feng, Jiahuai

2015-01-01

A high voltage capacitor is described in this paper. The capacitor uses glycerol as energy storage medium, has a large capacitance close to 1 nF, can hold off voltages of up to 100 kV for μs charging time. Allowing for low inductance, the capacitor electrode is designed as coaxial structure, which is different from the common structure of the ceramic capacitor. With a steady capacitance at different frequencies and a high hold-off voltage of up to 100 kV, the glycol capacitor design provides a potential substitute for the ceramic capacitors in pulse-forming network modulator to generate high voltage pulses with a width longer than 100 ns.

Reliability-oriented Design of a Cost-effective Active Capacitor

DEFF Research Database (Denmark)

Wang, Haoran; Wang, Huai

2017-01-01

This paper presents the reliability-oriented design of a two-terminal active capacitor proposed recently. The two-terminal active capacitor has the same level of convenience as a passive capacitor with reduced requirement of overall energy storage. In order to fully explore the potential...... of the proposed concept, a comprehensive design procedure is necessary to optimally sizing the key components of the active capacitor in terms of cost and reliability. Moreover, the inherent condition monitoring capability of the active capacitor is discussed by utilizing the existing feedback signals. A 500 W...

Dielectric material options for integrated capacitors

NARCIS (Netherlands)

Ruhl, G.; Lehnert, W.; Lukosius, M.; Wenger, C.; Baristiran Kaynak, C.; Blomberg, T.; Haukka, S.; Baumann, P.K.; Besling, W.F.A.; Roest, A.L.; Riou, B.; Lhostis, S.; Halimaou, A.; Roozeboom, F.; Langereis, E.; Kessels, W.M.M.; Zauner, A.; Rushworth, S.A.

2014-01-01

Future MIM capacitor generations will require significantly increased specific capacitances by utilization of high-k dielectric materials. In order to achieve high capacitance per chip area, these dielectrics have to be deposited in three-dimensional capacitor structures by ALD or AVD (atomic vapor

NEPP Evaluation of Automotive Grade Tantalum Chip Capacitors

Science.gov (United States)

Sampson, Mike; Brusse, Jay

2018-01-01

Automotive grade tantalum (Ta) chip capacitors are available at lower cost with smaller physical size and higher volumetric efficiency compared to military/space grade capacitors. Designers of high reliability aerospace and military systems would like to take advantage of these attributes while maintaining the high standards for long-term reliable operation they are accustomed to when selecting military-qualified established reliability tantalum chip capacitors (e.g., MIL-PRF-55365). The objective for this evaluation was to assess the long-term performance of off-the-shelf automotive grade Ta chip capacitors (i.e., manufacturer self-qualified per AEC Q-200). Two (2) lots of case size D manganese dioxide (MnO2) cathode Ta chip capacitors from 1 manufacturer were evaluated. The evaluation consisted of construction analysis, basic electrical parameter characterization, extended long-term (2000 hours) life testing and some accelerated stress testing. Tests and acceptance criteria were based upon manufacturer datasheets and the Automotive Electronics Council's AEC Q-200 qualification specification for passive electronic components. As-received a few capacitors were marginally above the specified tolerance for capacitance and ESR. X-ray inspection found that the anodes for some devices may not be properly aligned within the molded encapsulation leaving less than 1 mil thickness of the encapsulation. This evaluation found that the long-term life performance of automotive grade Ta chip capacitors is generally within specification limits suggesting these capacitors may be suitable for some space applications.

Rough Electrode Creates Excess Capacitance in Thin-Film Capacitors.

Science.gov (United States)

Torabi, Solmaz; Cherry, Megan; Duijnstee, Elisabeth A; Le Corre, Vincent M; Qiu, Li; Hummelen, Jan C; Palasantzas, George; Koster, L Jan Anton

2017-08-16

The parallel-plate capacitor equation is widely used in contemporary material research for nanoscale applications and nanoelectronics. To apply this equation, flat and smooth electrodes are assumed for a capacitor. This essential assumption is often violated for thin-film capacitors because the formation of nanoscale roughness at the electrode interface is very probable for thin films grown via common deposition methods. In this work, we experimentally and theoretically show that the electrical capacitance of thin-film capacitors with realistic interface roughness is significantly larger than the value predicted by the parallel-plate capacitor equation. The degree of the deviation depends on the strength of the roughness, which is described by three roughness parameters for a self-affine fractal surface. By applying an extended parallel-plate capacitor equation that includes the roughness parameters of the electrode, we are able to calculate the excess capacitance of the electrode with weak roughness. Moreover, we introduce the roughness parameter limits for which the simple parallel-plate capacitor equation is sufficiently accurate for capacitors with one rough electrode. Our results imply that the interface roughness beyond the proposed limits cannot be dismissed unless the independence of the capacitance from the interface roughness is experimentally demonstrated. The practical protocols suggested in our work for the reliable use of the parallel-plate capacitor equation can be applied as general guidelines in various fields of interest.

Efficiency Improvement of Capacitor Operation

Directory of Open Access Journals (Sweden)

V. P. Kashcheev

2010-01-01

Full Text Available A system of modernized capacitor ball-cleaning that prevents formation of depositions on internal capacitor tube surface has been developed in the paper.The system has been introduced at the Minsk TPP-4 (Power Block No.5. The paper presupposes that the economic effect will be nearly 0.43 million US dollars per year at one poer block with turbine Т-250/300-240.

Dual power, constant speed electric motor system

Science.gov (United States)

Kirschbaum, H.S.

1984-07-31

A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level. 6 figs.

Dual power, constant speed electric motor system

Science.gov (United States)

Kirschbaum, Herbert S.

1984-01-01

A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level.

Application of PFN capacitors in high power systems

International Nuclear Information System (INIS)

Parker, R.D.

1979-01-01

The application of lightweight reliable capacitors in a mobile energy store is discussed. The relationship of system design parameters to capacitor size and life is displayed. Electric fields and weights of a 21 J/lb and a 77 J/lb pulse discharge capacitor design are given. Estimates of future near-tern development are made

Infant-mortality testing of high-energy-density capacitors used on Nova

International Nuclear Information System (INIS)

Merritt, B.T.; Whitham, K.

1983-01-01

Nova is a solid-state large laser for inertial-confinement fusion research. Its flashlamps are driven by a 60-MJ capacitor bank. Part of this bank is being built with high-energy-density capacitors, 52-μF, 22 kV, 12.5 kJ. A total of 2645 of these capacitors have been purchased from two manufacturers. Each capacitor was infant-mortality tested. The first test consisted of a high-potential test, bushing-to-case, since these capacitors have dual bushings. Then the capacitors were discharged 500 times with circuit conditions approximating the capacitors normal flashlamp load. Failure of either of these tests or if the capacitor was leaking was cause for rejection

Shapeable short circuit resistant capacitor

Science.gov (United States)

Taylor, Ralph S.; Myers, John D.; Baney, William J.

2015-10-06

A ceramic short circuit resistant capacitor that is bendable and/or shapeable to provide a multiple layer capacitor that is extremely compact and amenable to desirable geometries. The capacitor that exhibits a benign failure mode in which a multitude of discrete failure events result in a gradual loss of capacitance. Each event is a localized event in which localized heating causes an adjacent portion of one or both of the electrodes to vaporize, physically cleaning away electrode material from the failure site. A first metal electrode, a second metal electrode, and a ceramic dielectric layer between the electrodes are thin enough to be formed in a serpentine-arrangement with gaps between the first electrode and the second electrode that allow venting of vaporized electrode material in the event of a benign failure.

Graphene-Based Flexible and Transparent Tunable Capacitors.

Science.gov (United States)

Man, Baoyuan; Xu, Shicai; Jiang, Shouzheng; Liu, Aihua; Gao, Shoubao; Zhang, Chao; Qiu, Hengwei; Li, Zhen

2015-12-01

We report a kind of electric field tunable transparent and flexible capacitor with the structure of graphene-Bi1.5MgNb1.5O7 (BMN)-graphene. The graphene films with low sheet resistance were grown by chemical vapor deposition. The BMN thin films were fabricated on graphene by using laser molecular beam epitaxy technology. Compared to BMN films grown on Au, the samples on graphene substrates show better quality in terms of crystallinity, surface morphology, leakage current, and loss tangent. By transferring another graphene layer, we fabricated flexible and transparent capacitors with the structure of graphene-BMN-graphene. The capacitors show a large dielectric constant of 113 with high dielectric tunability of ~40.7 % at a bias field of 1.0 MV/cm. Also, the capacitor can work stably in the high bending condition with curvature radii as low as 10 mm. This flexible film capacitor has a high optical transparency of ~90 % in the visible light region, demonstrating their potential application for a wide range of flexible electronic devices.

Energy Efficient Graphene Based High Performance Capacitors.

Science.gov (United States)

Bae, Joonwon; Kwon, Oh Seok; Lee, Chang-Soo

2017-07-10

Graphene (GRP) is an interesting class of nano-structured electronic materials for various cutting-edge applications. To date, extensive research activities have been performed on the investigation of diverse properties of GRP. The incorporation of this elegant material can be very lucrative in terms of practical applications in energy storage/conversion systems. Among various those systems, high performance electrochemical capacitors (ECs) have become popular due to the recent need for energy efficient and portable devices. Therefore, in this article, the application of GRP for capacitors is described succinctly. In particular, a concise summary on the previous research activities regarding GRP based capacitors is also covered extensively. It was revealed that a lot of secondary materials such as polymers and metal oxides have been introduced to improve the performance. Also, diverse devices have been combined with capacitors for better use. More importantly, recent patents related to the preparation and application of GRP based capacitors are also introduced briefly. This article can provide essential information for future study. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Pressure Effects Analysis of National Ignition Facility Capacitor Module Events

International Nuclear Information System (INIS)

Brereton, S; Ma, C; Newton, M; Pastrnak, J; Price, D; Prokosch, D

1999-01-01

Capacitors and power conditioning systems required for the National Ignition Facility (NIF) have experienced several catastrophic failures during prototype demonstration. These events generally resulted in explosion, generating a dramatic fireball and energetic shrapnel, and thus may present a threat to the walls of the capacitor bay that houses the capacitor modules. The purpose of this paper is to evaluate the ability of the capacitor bay walls to withstand the overpressure generated by the aforementioned events. Two calculations are described in this paper. The first one was used to estimate the energy release during a fireball event and the second one was used to estimate the pressure in a capacitor module during a capacitor explosion event. Both results were then used to estimate the subsequent overpressure in the capacitor bay where these events occurred. The analysis showed that the expected capacitor bay overpressure was less than the pressure tolerance of the walls. To understand the risk of the above events in NIF, capacitor module failure probabilities were also calculated. This paper concludes with estimates of the probability of single module failure and multi-module failures based on the number of catastrophic failures in the prototype demonstration facility

Electrochemical capacitor

Science.gov (United States)

Anderson, Marc A.; Liu, Kuo -Chuan; Mohr, Charles M.

1999-10-05

An inexpensive porous metal oxide material having high surface area, good conductivity and high specific capacitance is advantageously used in an electrochemical capacitor. The materials are formed in a sol-gel process which affords control over the properties of the resultant metal oxide materials.

Switchable capacitor

NARCIS (Netherlands)

Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, H.A.C.; Tilmans, Hendrikus; De Raedt, Walter

2011-01-01

A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom elecrode, a dielaectric layer deposited on at least part of sai bottum electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to the

Switchable capacitor

NARCIS (Netherlands)

Rottenberg, X.; Jansen, Henricus V.; Tilmans, H.A.C.; De Raedt, W.

2003-01-01

A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom elecrode, a dielaectric layer deposited on at least part of sai bottum electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to the

Humidity Testing of PME and BME Ceramic Capacitors with Cracks

Science.gov (United States)

Teverovsky, Alexander A.; Herzberger, Jaemi

2014-01-01

Cracks in ceramic capacitors are one of the major causes of failures during operation of electronic systems. Humidity testing has been successfully used for many years to verify the absence of cracks and assure quality of military grade capacitors. Traditionally, only precious metal electrode (PME) capacitors were used in high reliability applications and the existing requirements for humidity testing were developed for this type of parts. With the advance of base metal electrode (BME) capacitors, there is a need for assessment of the applicability of the existing techniques for the new technology capacitors. In this work, variety of different PME and BME capacitors with introduced cracks were tested in humid environments at different voltages and temperatures. Analysis of the test results indicates differences in the behavior and failure mechanisms for BME and PME capacitors and the need for different testing conditions.

Reliability Evaluation of Power Capacitors in a Wind Turbine System

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede

2018-01-01

With the increasing penetration of wind power, reliable and cost-effective wind energy production is of more and more importance. The doubly-fed induction generator based partial-scale wind power converter is still dominating in the existing wind farms. In this paper, the reliability assessment...... block diagram is used to bridge the gap between the Weibull distribution based component-level individual capacitor and the capacitor bank. A case study of a 2 MW wind power converter shows that the lifetime is significantly reduced from the individual capacitor to the capacitor bank. Besides, the dc...... of power capacitors is studied considering the annual mission profile. According to an electro-thermal stress evaluation, the time-to-failure distribution of both the dc-link capacitor and ac-side filter capacitor is detailed investigated. Aiming for the systemlevel reliability analysis, a reliability...

Fast risetime one megajoule capacitor bank

International Nuclear Information System (INIS)

Markins, D.; Baker, W.L.; Reinovsky, R.E.; Clark, J.G.

1976-01-01

A 100 kV, 1.1 MJ capacitor bank for plasma research experiments has been constructed for the Air Force Weapons Laboratory. The system consists of twenty, individual, low inductance capacitor modules, each utilizing a four element switch package approximately 2 meters wide. Each module contains twenty-four ''scyllac'' type 1.85 μF capacitors. A 100 kV output pulse is obtained by charging the top half of each module to +50 kV and the bottom half to -50 kV. A pressurized, low inductance multichannel switch package incorporating four separately triggered elements is designed to fit into the parallel plate transmission line system of the capacitor module. The bank is configured in a cross shape with twenty modules spaced uniformly around the perimeter of a parallel plate transmission line. The transmission line is constructed with 32 mil aluminum and insulated with 60 mils of mylar. The bank is designed to feed an easily replaceable central coaxial load. The entire system has been repeatedly fired at 100 kV with a dummy resistive load and has delivered 2.2 x 10 7 amperes of current with a risetime of 1.1 μsec. The total measured system inductance is 2.2 nH. This system represents a significant advance in the development of reliable, fast, high current capacitor banks

Discontinuous Galerkin Time-Domain Analysis of Power-Ground Planes Taking Into Account Decoupling Capacitors

KAUST Repository

Li, Ping

2017-03-22

In this paper, a discontinuous Galerkin time-domain (DGTD) method is developed to analyze the power-ground planes taking into account the decoupling capacitors. In the presence of decoupling capacitors, the whole physical system can be split into two subsystems: 1) the field subsystem that is governed by Maxwell\\'s equations that will be solved by the DGTD method, and 2) the circuit subsystem including the capacitor and its parasitic inductor and resistor, which is going to be characterized by the modified nodal analysis algorithm constructed circuit equations. With the aim to couple the two subsystems together, a lumped port is defined over a coaxial surface between the via barrel and the ground plane. To reach the coupling from the field to the circuit subsystem, a lumped voltage source calculated by the integration of electric field along the radial direction is introduced. On the other hand, to facilitate the coupling from the circuit to field subsystem, a lumped port current source calculated from the circuit equation is introduced, which serves as an impressed current source for the field subsystem. With these two auxiliary terms, a hybrid field-circuit matrix equation is established, which enables the field and circuit subsystems are solved in a synchronous scheme. Furthermore, the arbitrarily shaped antipads are considered by enforcing the proper wave port excitation using the magnetic surface current source derived from the antipads supported electric eigenmodes. In this way, the S-parameters corresponding to different modes can be conveniently extracted. To further improve the efficiency of the proposed algorithm in handling multiscale meshes, the local time-stepping marching scheme is applied. The proposed algorithm is verified by several representative examples.

A 800 kV compact peaking capacitor for nanosecond generator.

Science.gov (United States)

Jia, Wei; Chen, Zhiqiang; Tang, Junping; Chen, Weiqing; Guo, Fan; Sun, Fengrong; Li, Junna; Qiu, Aici

2014-09-01

An extremely compact high voltage peaking capacitor is developed. The capacitor has a pancake structure with a diameter of 315 mm, a thickness of 59 mm, and a mass of 6.1 kg. The novel structural design endows the capacitor with a better mechanical stability and reliability under hundreds of kilovolts pulse voltage and an inner gas pressure of more than 1.5 MPa. The theoretical value of the capacitor self-inductance is near to 17 nH. Proved by series of electrical experiments, the capacitor can endure a high-voltage pulse with a rise time of about 20 ns, a half-width duration of around 25 ns, and an amplitude of up to 800 kV in a single shot model. When the capacitor was used in an electromagnetic pulse simulator as a peaking capacitor, the rise time of the voltage pulse can be reduced from 20 ns to less than 3 ns. The practical value of the capacitor's inductance deduced from the experimental date is no more than 25 nH.

A Power-Efficient Wireless Capacitor Charging System Through an Inductive Link.

Science.gov (United States)

Lee, Hyung-Min; Ghovanloo, Maysam

2013-10-01

A power-efficient wireless capacitor charging system for inductively powered applications has been presented. A bank of capacitors can be directly charged from an ac source by generating a current through a series charge injection capacitor and a capacitor charger circuit. The fixed charging current reduces energy loss in switches, while maximizing the charging efficiency. An adaptive capacitor tuner compensates for the resonant capacitance variations during charging to keep the amplitude of the ac input voltage at its peak. We have fabricated the capacitor charging system prototype in a 0.35- μ m 4-metal 2-poly standard CMOS process in 2.1 mm 2 of chip area. It can charge four pairs of capacitors sequentially. While receiving 2.7-V peak ac input through a 2-MHz inductive link, the capacitor charging system can charge each pair of 1 μ F capacitors up to ±2 V in 420 μ s, achieving a high measured charging efficiency of 82%.

Development of High Temperature Capacitor Technology and Manufacturing Capability

Energy Technology Data Exchange (ETDEWEB)

None, None

2011-05-15

The goal of the Development of High Temperature Capacitor Technology and Manufacturing Capability program was to mature a production-ready supply chain for reliable 250°C FPE (fluorinated polyester) film capacitors by 2011. These high-temperature film capacitors enable both the down hole drilling and aerospace industries by enabling a variety of benefits including: - Deeper oil exploration in higher temperature and pressure environments - Enabling power electronic and control equipment to operate in higher temperature environments - Enabling reduced cooling requirements of electronics - Increasing reliability and life of capacitors operating below rated temperature - Enabling capacitors to handle higher electrical losses without overheating. The key challenges to bringing the FPE film capacitors to market have been manufacturing challenges including: - FPE Film is difficult to handle and wind, resulting in poor yields - Voltage breakdown strength decreases when the film is wound into capacitors (~70% decrease) - Encapsulation technologies must be improved to enable higher perature operation - Manufacturing and test cycle time is very long As a direct result of this program most of the manufacturing challenges have been met. The FPE film production metalization and winding yield has increased to over 82% from 70%, and the voltage breakdown strength of the wound capacitors has increased 270% to 189 V/μm. The high temperature packaging concepts are showing significant progress including promising results for lead attachments and hermetic packages at 200°C and non-hermetic packages at 250°C. Manufacturing and test cycle time will decrease as the market for FPE capacitors develops.

Switched-capacitor multiply-by-two amplifier with reduced capacitor mismatches sensitivity and full swing sample signal common-mode voltage

International Nuclear Information System (INIS)

Xu Xinnan; Yao Suying; Xu Jiangtao; Nie Kaiming

2012-01-01

A switched-capacitor amplifier with an accurate gain of two that is insensitive to component mismatch is proposed. This structure is based on associating two sets of two capacitors in cross series during the amplification phase. This circuit permits the common-mode voltage of the sample signal to reach full swing. Using the charge-complement technique, the proposed amplifier can reduce the impact of parasitic capacitors on the gain accuracy effectively. Simulation results show that as sample signal common-mode voltage changes, the difference between the minimum and maximum gain error is less than 0.03%. When the capacitor mismatch is increased from 0 to 0.2%, the gain error is deteriorated by 0.00015%. In all simulations, the gain of amplifier is 69 dB. (semiconductor integrated circuits)

PLZT capacitor on glass substrate

Science.gov (United States)

Fairchild, M. Ray; Taylor, Ralph S.; Berlin, Carl W.; Wong, Celine W. K.; Ma, Beihai; Balachandran, Uthamalingam

2016-01-05

A lead-lanthanum-zirconium-titanate (PLZT) capacitor on a substrate formed of glass. The first metallization layer is deposited on a top side of the substrate to form a first electrode. The dielectric layer of PLZT is deposited over the first metallization layer. The second metallization layer deposited over the dielectric layer to form a second electrode. The glass substrate is advantageous as glass is compatible with an annealing process used to form the capacitor.

BioCapacitor: A novel principle for biosensors.

Science.gov (United States)

Sode, Koji; Yamazaki, Tomohiko; Lee, Inyoung; Hanashi, Takuya; Tsugawa, Wakako

2016-02-15

Studies regarding biofuel cells utilizing biocatalysts such as enzymes and microorganisms as electrocatalysts have been vigorously conducted over the last two decades. Because of their environmental safety and sustainability, biofuel cells are expected to be used as clean power generators. Among several principles of biofuel cells, enzyme fuel cells have attracted significant attention for their use as alternative energy sources for future implantable devices, such as implantable insulin pumps and glucose sensors in artificial pancreas and pacemakers. However, the inherent issue of the biofuel cell principle is the low power of a single biofuel cell. The theoretical voltage of biofuel cells is limited by the redox potential of cofactors and/or mediators employed in the anode and cathode, which are inadequate for operating any devices used for biomedical application. These limitations inspired us to develop a novel biodevice based on an enzyme fuel cell that generates sufficient stable power to operate electric devices, designated "BioCapacitor." To increase voltage, the enzyme fuel cell is connected to a charge pump. To obtain a sufficient power and voltage to operate an electric device, a capacitor is used to store the potential generated by the charge pump. Using the combination of a charge pump and capacitor with an enzyme fuel cell, high voltages with sufficient temporary currents to operate an electric device were generated without changing the design and construction of the enzyme fuel cell. In this review, the BioCapacitor principle is described. The three different representative categories of biodevices employing the BioCapacitor principle are introduced. Further, the recent challenges in the developments of self-powered stand-alone biodevices employing enzyme fuel cells combined with charge pumps and capacitors are introduced. Finally, the future prospects of biodevices employing the BioCapacitor principle are addressed. Copyright © 2015 The Authors

Infant mortality testing of high energy-density capacitors used on Nova

International Nuclear Information System (INIS)

Merritt, B.T.; Whitham, K.

1983-01-01

Nova is a solid state large laser for inertial confinement fusion research. Its flashlamps are driven by a 60 MJ capacitor bank. Part of this bank is being built with high energy-density capacitors, 52 μF, 22 KV, 12.5 KJ. A total of 2,645 of these capacitors have been purchased from two manufacturers. Each capacitor was infant mortality tested. The first test consisted of a high-potential test, bushing-to-case, since these capacitors have dual bushings. Then the capacitors were discharged 500 times with circuit conditions approximating the capacitors normal flashlamp load. Failure of either of these tests or if the capacitor was leaking was cause for rejection. The test results were remarkably good. Less than 0.5 percent failed the pulse-discharge test and less than 2.5 percent were rejected overall

Design and Characterization of Vertical Mesh Capacitors in Standard CMOS

DEFF Research Database (Denmark)

Christensen, Kåre Tais

2001-01-01

This paper shows how good RF capacitors can be made in a standard digital CMOS process. The capacitors which are also well suited for binary weighted switched capacitor banks show very good RF performance: Q-values of 57 at 4.0 GHz, a density of 0.27 fF/μ2, 2.2 μm wide shielded unit capacitors, 6...

Leakage Currents in Low-Voltage PME and BME Ceramic Capacitors

Science.gov (United States)

Teverovsky, Alexander

2015-01-01

Introduction of BME capacitors to high-reliability electronics as a replacement for PME capacitors requires better understanding of changes in performance and reliability of MLCCs to set justified screening and qualification requirements. In this work, absorption and leakage currents in various lots of commercial and military grade X7R MLCCs rated to 100V and less have been measured to reveal difference in behavior of PME and BME capacitors in a wide range of voltages and temperatures. Degradation of leakage currents and failures in virgin capacitors and capacitors with introduced cracks has been studied at different voltages and temperatures during step stress highly accelerated life testing. Mechanisms of charge absorption, conduction and degradation have been discussed and a failure model in capacitors with defects suggested.

Fifth harmonic and sag impact on PMSG wind turbines with a balancing new strategy for capacitor voltages

International Nuclear Information System (INIS)

Seixas, M.; Melício, R.; Mendes, V.M.F.

2014-01-01

Highlights: • Impact on wind turbines due to fifth harmonic and sag content. • Converter topologies considered are two-level and three-level ones. • Controllers are based on PI and fractional-order methods. • New control strategy for the selection of output voltage vectors. • Balancing voltages in the DC-link capacitors. - Abstract: This paper deals with the computing simulation of the impact on permanent magnet synchronous generator wind turbines due to fifth harmonic content and grid voltage decrease. Power converter topologies considered in the simulations are the two-level and the three-level ones. The three-level converters are limited by unbalance voltages in the DC-link capacitors. In order to lessen this limitation, a new control strategy for the selection of the output voltage vectors is proposed. Controller strategies considered in the simulation are respectively based on proportional integral and fractional-order controllers. Finally, a comparison between the results of the simulations with the two controller strategies is presented in order to show the main advantage of the proposed strategy

Simple Ways to Make Real Capacitors

Science.gov (United States)

Herman, Rhett

2014-01-01

Many of us have grabbed two pieces of aluminum foil and a paper towel, quickly sandwiched them together, and exclaimed in lecture, "Look! It's easy to make a capacitor!" Then we move on from there, calculating things such as capacitances with various dielectrics or plate sizes, the capacitance of capacitor networks, RC circuits,…

Cellulose Triacetate Dielectric Films For Capacitors

Science.gov (United States)

Yen, Shiao-Ping S.; Jow, T. Richard

1994-01-01

Cellulose triacetate investigated for use as dielectric material in high-energy-density capacitors for pulsed-electrical-power systems. Films of cellulose triacetate metalized on one or both sides for use as substrates for electrodes and/or as dielectrics between electrodes in capacitors. Used without metalization as simple dielectric films. Advantages include high breakdown strength and self-healing capability.

Modelling of storage of the photovoltaic energy by super-capacitors

International Nuclear Information System (INIS)

Camara, Mohamed Ansoumane

2011-01-01

The storage by ultra-capacitors of photovoltaic energy is modeled in order to have an accurate and accessible model to integrate ultra-capacitors into solar energy conversion systems. Ultra-capacitors are modeled by a multi-branch circuit representation composed of resistors and capacitors with variable voltage whose values are determined by an accurate characterization experiment. Moreover, all the elements of a typical photovoltaic energy conversion system are modeled by using the Matlab/Simulink software (solar radiation, photovoltaic arrays, regulator, batteries and charges). The energy storage model by ultra-capacitors is then validated by the good agreement of measured values taken in real conditions with the results provided by simulations. Finally, two examples are proposed and discussed: the determination of the storage duration of ultra-capacitors versus solar irradiance and ambient temperature, and the integration of ultra-capacitors in the electrical feeding system of a DC motor to reduce the electrical current peak of the battery at the start of the motor. (author) [fr

Reliability of capacitors for DC-link applications - An overview

DEFF Research Database (Denmark)

Wang, Huai; Blaabjerg, Frede

2013-01-01

DC-link capacitors are an important part in the majority of power electronic converters which contribute to cost, size and failure rate on a considerable scale. From capacitor users' viewpoint, this paper presents a review on the improvement of reliability of DC-link in power electronic converters...... from two aspects: 1) reliability-oriented DC-link design solutions; 2) conditioning monitoring of DC-link capacitors during operation. Failure mechanisms, failure modes and lifetime models of capacitors suitable for the applications are also discussed as a basis to understand the physics......-of-failure. This review serves to provide a clear picture of the state-of-the-art research in this area and to identify the corresponding challenges and future research directions for capacitors and their DC-link applications....

Two-Capacitor Problem: A More Realistic View.

Science.gov (United States)

Powell, R. A.

1979-01-01

Discusses the two-capacitor problem by considering the self-inductance of the circuit used and by determining how well the usual series RC circuit approximates the two-capacitor problem when realistic values of L, C, and R are chosen. (GA)

Embryo splitting

Directory of Open Access Journals (Sweden)

Karl Illmensee

2010-04-01

Full Text Available Mammalian embryo splitting has successfully been established in farm animals. Embryo splitting is safely and efficiently used for assisted reproduction in several livestock species. In the mouse, efficient embryo splitting as well as single blastomere cloning have been developed in this animal system. In nonhuman primates embryo splitting has resulted in several pregnancies. Human embryo splitting has been reported recently. Microsurgical embryo splitting under Institutional Review Board approval has been carried out to determine its efficiency for blastocyst development. Embryo splitting at the 6–8 cell stage provided a much higher developmental efficiency compared to splitting at the 2–5 cell stage. Embryo splitting may be advantageous for providing additional embryos to be cryopreserved and for patients with low response to hormonal stimulation in assisted reproduction programs. Social and ethical issues concerning embryo splitting are included regarding ethics committee guidelines. Prognostic perspectives are presented for human embryo splitting in reproductive medicine.

Physics Based Modeling and Prognostics of Electrolytic Capacitors

Science.gov (United States)

Kulkarni, Chetan; Ceyla, Jose R.; Biswas, Gautam; Goebel, Kai

2012-01-01

This paper proposes first principles based modeling and prognostics approach for electrolytic capacitors. Electrolytic capacitors have become critical components in electronics systems in aeronautics and other domains. Degradations and faults in DC-DC converter unit propagates to the GPS and navigation subsystems and affects the overall solution. Capacitors and MOSFETs are the two major components, which cause degradations and failures in DC-DC converters. This type of capacitors are known for its low reliability and frequent breakdown on critical systems like power supplies of avionics equipment and electrical drivers of electromechanical actuators of control surfaces. Some of the more prevalent fault effects, such as a ripple voltage surge at the power supply output can cause glitches in the GPS position and velocity output, and this, in turn, if not corrected will propagate and distort the navigation solution. In this work, we study the effects of accelerated aging due to thermal stress on different sets of capacitors under different conditions. Our focus is on deriving first principles degradation models for thermal stress conditions. Data collected from simultaneous experiments are used to validate the desired models. Our overall goal is to derive accurate models of capacitor degradation, and use them to predict performance changes in DC-DC converters.

A Humidity-Dependent Lifetime Derating Factor for DC Film Capacitors

DEFF Research Database (Denmark)

Wang, Huai; Reigosa, Paula Diaz; Blaabjerg, Frede

2015-01-01

accelerated testing of film capacitors under different humidity conditions, enabling a more justified lifetime prediction of film capacitors for DC-link applications under specific climatic environments. The analysis of the testing results and the detailed discussion on the derating factor with different......Film capacitors are widely assumed to have superior reliability performance than Aluminum electrolytic capacitors in DC-link design of power electronic converters. However, the assumption needs to be critically judged especially for applications under high humidity environments. This paper proposes...... a humidity-dependent lifetime derating factor for a type of plastic-boxed metallized DC film capacitors. It overcomes the limitation that the humidity impact is not considered in the state-of-the-art DC film capacitor lifetime models. The lifetime derating factor is obtained based on a total of 8,700 hours...

MOSFET and MOS capacitor responses to ionizing radiation

Science.gov (United States)

Benedetto, J. M.; Boesch, H. E., Jr.

1984-01-01

The ionizing radiation responses of metal oxide semiconductor (MOS) field-effect transistors (FETs) and MOS capacitors are compared. It is shown that the radiation-induced threshold voltage shift correlates closely with the shift in the MOS capacitor inversion voltage. The radiation-induced interface-state density of the MOSFETs and MOS capacitors was determined by several techniques. It is shown that the presence of 'slow' states can interfere with the interface-state measurements.

Pseudo-capacitor device for aqueous electrolytes

Science.gov (United States)

Prakash, Jai; Thackeray, Michael M.; Dees, Dennis W.; Vissers, Donald R.; Myles, Kevin M.

1998-01-01

A pseudo-capacitor having a high energy storage capacity develops a double layer capacitance as well as a Faradaic or battery-like redox reaction, also referred to as pseudo-capacitance. The Faradaic reaction gives rise to a capacitance much greater than that of the typical ruthenate oxide ultracapacitor which develops only charge separation-based double layer capacitance. The capacitor employs a lead and/or bismuth/ruthenate and/or iridium system having the formula A.sub.2 ›B.sub.2-x Pb.sub.x !O.sub.7-y, where A=Pb, Bi, and B=Ru, Ir, and Ocapacitor. The amount of expensive ruthenate and iridium can be substantially reduced in the pseudo-capacitor by increasing the lead content while improving energy storage capacity.

Radiation effects in polycarbonate capacitors

Directory of Open Access Journals (Sweden)

Vujisić Miloš

2009-01-01

Full Text Available The aim of this paper is to examine the influence of neutron and gamma irradiation on the dissipation factor and capacitance of capacitors with polycarbonate dielectrics. The operation of capacitors subject to extreme conditions, such as the presence of ionizing radiation fields, is of special concern in military industry and space technology. Results obtained show that the exposure to a mixed neutron and gamma radiation field causes a decrease of capacitance, while the loss tangent remains unchanged.

Low-Voltage Switched-Capacitor Circuits

DEFF Research Database (Denmark)

Bidari, E.; Keskin, M.; Maloberti, F.

1999-01-01

Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications.......Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications....

Fabrication of wound capacitors using flexible alkali-free glass

International Nuclear Information System (INIS)

Wilke, Rudeger H. T.; Baker, Amanda; Brown-Shaklee, Harlan; Johnson-Wilke, Raegan; Hettler, Chad

2016-01-01

Here, alkali-free glasses, which exhibit high energy storage densities (~35 J/cc), present a unique opportunity to couple high temperature stability with high breakdown strength, and thus provide an avenue for capacitor applications with stringent temperature and power requirements. Realizing the potential of these materials in kilovolt class capacitors with >1 J/cc recoverable energy density requires novel packaging strategies that incorporate these extremely fragile dielectrics. In this paper, we demonstrate the feasibility of fabricating wound capacitors using 50-μm-thick glass. Two capacitors were fabricated from 2.8-m-long ribbons of thin (50 μm) glass wound into 125-140-mm-diameter spools. The capacitors exhibit a capacitance of 70-75 nF with loss tangents below 1%. The wound capacitors can operate up to 1 kV and show excellent temperature stability to 150 °C. By improving the end terminations, the self-resonance can be shifted to above 1 MHz, indicating that these materials may be useful for pulsed power applications with microsecond discharge times.

Nonmedical application of computed tomography to power capacitor quality assesment

International Nuclear Information System (INIS)

Kruger, R.P.

1981-01-01

Present research and development efforts at Los Alamos Scientific Laboratory require the design and use of high-efficiency rapid-discharge energy storage capacitors for laser isotope separation and plasma physics programs. In these applications, capacitors are subjected to electrical, mechanical, thermal, and other environmental stresses. These stresses cause the dielectric constant to change due to gasification from arcing at nonsoldering connections, which produce a chemical reduction of the dielectric material. This effectively limits the lifetime of the capacitor. The programs mentioned above require capacitors with a multikilohertz frequency response at a current of tens of kiloamperes and a voltage of at least 100 kV. The lifetime of such capacitors should exceed 10 10 charge/discharge cycles. Such capacitors do not presently exist. The exploration of new capacitor designs will require the use of both electrical functional tests and tests that show the changes in internal physical structure as the capacitor is repeatedly stressed by the charge/discharge cycle. The integration of electrical and structural tests throughout the life cycle of a candidate capacitor makes it imperative that the structural integrity tests be nondestructive. Computed tomography (CT) makes this integration possible. The work reported here is the result of a pilot project designed to show the potential use of CT for this application. This work includes visualization of material defects using both a layered sequence of conventional tomographic slices and orthogonal multiangular pseudoradiographs generated from these slices

Li-Ion, Ultra-capacitor Based Hybrid Energy Module

National Research Council Canada - National Science Library

Daboussi, Zaher; Paryani, Anil; Khalil, Gus; Catherino, Henry; Gargies, Sonya

2007-01-01

.... To determine the optimum utilization of ultra-capacitors in applications where high power density and high energy density are required, an optimized Li-Ion/Ultra-capacitor Hybrid Energy Module (HEM...

A light-powered bio-capacitor with nanochannel modulation.

Science.gov (United States)

Rao, Siyuan; Lu, Shanfu; Guo, Zhibin; Li, Yuan; Chen, Deliang; Xiang, Yan

2014-09-03

An artificial bio-capacitor system is established, consisting of the proton-pump protein proteorhodopsin and a modified alumina nanochannel, inspired by the capacitor-like behavior of plasma membranes realized through the cooperation of ion-pump and ion-channel proteins. Capacitor-like features of this simplified system are realized and identified, and the photocurrent duration time can be modulated by nanochannel modification to obtain favorable square-wave currents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method of making dielectric capacitors with increased dielectric breakdown strength

Science.gov (United States)

Ma, Beihai; Balachandran, Uthamalingam; Liu, Shanshan

2017-05-09

The invention is directed to a process for making a dielectric ceramic film capacitor and the ceramic dielectric laminated capacitor formed therefrom, the dielectric ceramic film capacitors having increased dielectric breakdown strength. The invention increases breakdown strength by embedding a conductive oxide layer between electrode layers within the dielectric layer of the capacitors. The conductive oxide layer redistributes and dissipates charge, thus mitigating charge concentration and micro fractures formed within the dielectric by electric fields.

Microprocessor Controlled Capacitor Bank Switching System for ...

African Journals Online (AJOL)

In this work, analysis and development of a microprocessor controlled capacitor bank switching system for deployment in a smart distribution network was carried out. This system was implemented by the use of discreet components such as resistors, capacitors, transistor, diode, automatic voltage regulator, with the ...

Comparison of MOS capacitor and transistor postirradiation response

International Nuclear Information System (INIS)

McWhorter, P.J.; Fleetwood, D.M.; Pastorek, R.A.; Zimmerman, G.T.

1989-01-01

The postirradiation response of MOS capacitors and transistors fabricated on the same chip has been examined as a function of dose and anneal bias. A variety of analysis techniques are used to evaluate the postirradiation response of these structures, including low and high frequency capacitance-voltage techniques, subthreshold current-voltage techniques, and charge pumping. Though there are changes in the postirradiation energy spectrum of ΔD it , no clear evidence of defect transformation is observed on transistors or capacitors under any conditions examined. Postirradiation response at 80 degrees C is found to be similar in the two structures for low levels of damage (100 krad). For both structures, interface-trap densities continue to grow following irradiation under these conditions. In contrast, the postirradiation response of capacitors and transistors can differ qualitatively at higher levels of damage (1 Mrad), with interface-traps increasing postirradiation at 80 degrees C for transistors and annealing for capacitors. These results indicate that capacitor structures may not be suitable for hardness assurance studies that involve elevated temperature irradiations or postirradiation anneals

Study of electric capacitors using Finite Element Method

Directory of Open Access Journals (Sweden)

Alina Neamț

2012-12-01

Full Text Available A capacitor is made of two armatures and a dielectric between the two armatures. In this paper, we are going to study the plane capacitor , which is made of two equal metal armatures, plane and parallel, having the S surface, situated at a distance d much shorter than the armatures dimensions, between which there is a liniar, homogenous and isotropic dielectric having a constant electrical permittivity.The purpose of studying the plane capacitor, through MEF, presented in this paper,is to establish the stress to which the dielectrics may be subject to, in daily practice, and the influence that their superposition in an electric field has, on each of them. The study of the plane capacitor , finalised with observations on the raise of the dependence of the electric field intensity in air on the size of the air layer and having as parameter the type of dielectric material introduced between the armatures, is an example of confirmation or invalidation of the possibility and utility of using layers of dielectrics between the armatures of the capacitors.

Reliability Evaluation of Base-Metal-Electrode (BME) Multilayer Ceramic Capacitors for Space Applications

Science.gov (United States)

Liu, David (Donghang)

2011-01-01

This paper reports reliability evaluation of BME ceramic capacitors for possible high reliability space-level applications. The study is focused on the construction and microstructure of BME capacitors and their impacts on the capacitor life reliability. First, the examinations of the construction and microstructure of commercial-off-the-shelf (COTS) BME capacitors show great variance in dielectric layer thickness, even among BME capacitors with the same rated voltage. Compared to PME (precious-metal-electrode) capacitors, BME capacitors exhibit a denser and more uniform microstructure, with an average grain size between 0.3 and approximately 0.5 micrometers, which is much less than that of most PME capacitors. The primary reasons that a BME capacitor can be fabricated with more internal electrode layers and less dielectric layer thickness is that it has a fine-grained microstructure and does not shrink much during ceramic sintering. This results in the BME capacitors a very high volumetric efficiency. The reliability of BME and PME capacitors was investigated using highly accelerated life testing (HALT) and regular life testing as per MIL-PRF-123. Most BME capacitors were found to fail· with an early dielectric wearout, followed by a rapid wearout failure mode during the HALT test. When most of the early wearout failures were removed, BME capacitors exhibited a minimum mean time-to-failure of more than 10(exp 5) years. Dielectric thickness was found to be a critical parameter for the reliability of BME capacitors. The number of stacked grains in a dielectric layer appears to play a significant role in determining BME capacitor reliability. Although dielectric layer thickness varies for a given rated voltage in BME capacitors, the number of stacked grains is relatively consistent, typically between 10 and 20. This may suggest that the number of grains per dielectric layer is more critical than the thickness itself for determining the rated voltage and the life

Rotary capacitor

CERN Multimedia

CERN PhotoLab

1971-01-01

The rotating wheel of the rotary capacitor representing the most critical part of the new radio-frequency system of the synchro-cyclotron. The three rows of teeth on the circumference of the wheel pass between four rows of stator blades with a minimum clearance of 1 mm at a velocity of 1700 rev/min.

Liquid Crystals of Lithium Dodecylbenzenesulfonate for Electric Double Layer Capacitors

International Nuclear Information System (INIS)

Kuzmin, Andrey Vasil’evich; Yurtov, Evgeny V.

2016-01-01

Ionic lyotropic liquid crystals based on lithium dodecylbenzenesulfonate were used as electrolytes for electric double layer capacitors with carbon fibrous electrodes. The capacitors were tasted by cyclic voltammetry, galvanostatic charge and discharge, and impedance spectroscopy. The highest specific capacitance was achieved for electrical double layer capacitor equipped with ionic lyotropic liquid crystal of lithium dodecylbenzenesulfonate 35 wt% in water. The specific capacitance of capacitor was calculated from galvanostatic discharge curves – 15 F/g of carbon fibrous material

50V All-PMOS Charge Pumps Using Low-Voltage Capacitors

KAUST Repository

Emira, Ahmed

2012-10-06

In this work, two high-voltage charge pumps are introduced. In order to minimize the area of the pumping capacitors, which dominates the overall area of the charge pump, high density capacitors have been utilized. Nonetheless, these high density capacitors suffer from low breakdown voltage which is not compatible with the targeted high voltage application. To circumvent the breakdown limitation, a special clocking scheme is used to limit the maximum voltage across any pumping capacitor. The two charge pump circuits were fabricated in a 0:6m CMOS technology with poly0-poly1 capacitors. The output voltage of the two charge pumps reached 42:8V and 51V while the voltage across any capacitor did not exceed the value of the input voltage. Compared to other designs reported in the literature, the proposed charge pump provides the highest output voltage which makes it more suitable for tuning MEMS devices.

50V All-PMOS Charge Pumps Using Low-Voltage Capacitors

KAUST Repository

Emira, Ahmed; AbdelGhany, M.; Elsayed, M.; Elshurafa, Amro M.; Sedky, S.; Salama, Khaled N.

2012-01-01

In this work, two high-voltage charge pumps are introduced. In order to minimize the area of the pumping capacitors, which dominates the overall area of the charge pump, high density capacitors have been utilized. Nonetheless, these high density capacitors suffer from low breakdown voltage which is not compatible with the targeted high voltage application. To circumvent the breakdown limitation, a special clocking scheme is used to limit the maximum voltage across any pumping capacitor. The two charge pump circuits were fabricated in a 0:6m CMOS technology with poly0-poly1 capacitors. The output voltage of the two charge pumps reached 42:8V and 51V while the voltage across any capacitor did not exceed the value of the input voltage. Compared to other designs reported in the literature, the proposed charge pump provides the highest output voltage which makes it more suitable for tuning MEMS devices.

Negative capacitance in a ferroelectric capacitor.

Science.gov (United States)

Khan, Asif Islam; Chatterjee, Korok; Wang, Brian; Drapcho, Steven; You, Long; Serrao, Claudy; Bakaul, Saidur Rahman; Ramesh, Ramamoorthy; Salahuddin, Sayeef

2015-02-01

The Boltzmann distribution of electrons poses a fundamental barrier to lowering energy dissipation in conventional electronics, often termed as Boltzmann Tyranny. Negative capacitance in ferroelectric materials, which stems from the stored energy of a phase transition, could provide a solution, but a direct measurement of negative capacitance has so far been elusive. Here, we report the observation of negative capacitance in a thin, epitaxial ferroelectric film. When a voltage pulse is applied, the voltage across the ferroelectric capacitor is found to be decreasing with time--in exactly the opposite direction to which voltage for a regular capacitor should change. Analysis of this 'inductance'-like behaviour from a capacitor presents an unprecedented insight into the intrinsic energy profile of the ferroelectric material and could pave the way for completely new applications.

Effect of capacitor loss on discharging characteristics of xenon flash lamp

International Nuclear Information System (INIS)

Zhang Chu; Lin Dejiang; Xu Chunmei; Shen Hongbin; Chen Xiaohan

2012-01-01

The effect of storage capacitor's loss on the discharging characteristics of the xenon flash lamp was studied, and the xenon flash lamp discharging circuit was analyzed and improved. The capacitor can be equivalent to a series of an ideal capacitor and loss resistance. The improved formula of the xenon lamp discharging characteristics was given when actual capacitance loss is not zero, and the xenon lamp discharging current and discharging power are calculated and analyzed in detail with the increase of the capacitor loss. The results show that the increase of loss will lead to the decrease of xenon lamp discharging current and peak power and the xenon lamp flash time, and influence laser pumping efficiency. The loss will also lead to the capacitor inverse charging in LC discharging circuit; this will influence normal working of the capacitor and decrease the lift of the xenon lamp. The actual energy storage capacitor charging and discharging experiments show that the increase of capacitor loss will lead to the decrease of xenon lamp light-emitting waveform peak, shortening of the flash time and increase of the electrode sputter, thus verity, the reasonableness of theoretical analysis. In addition, the experiments show that environmental factors have very significant impact on the increase of the storage capacitor loss. (authors)

Electrically and thermally activated ageing mechanisms in metallised polymer film capacitors

International Nuclear Information System (INIS)

Lee, Yuen Pen

2001-01-01

This dissertation describes a combined computational and experimental study to understand the fundamental electrostatic, thermal, electromagnetic, and discharge related processes during the ageing of metallised polymer film capacitors. In the event of internal breakdowns, these capacitors are capable of 'self-healing' through a controlled isolation of defects on the electrode surfaces by mosaic patterning the electrode. The objective of this project is to develop viable computer models to unravel electrothermally activated ageing processes in capacitors. To provide the necessary validation to any capacitor models developed, our work is supported by comprehensive experiments including industrial standard accelerated life tests and associated breakdown damage analyses of tested capacitors. These have enabled an empirical identification of main factors affecting the reliability and lifetime of capacitors. Relevant raw data and the qualitative picture enabled by these data are crucial to the development and refinement of viable computational models of capacitors. Given the complexity of ageing processes, it is both very difficult and unnecessary to develop a one-for-all model that describes indiscriminately all relevant processes. The approach adapted in this work has been to prioritise key ageing processes and modularise each process with its own computer model. The overall picture of capacitor ageing can then be unravelled by integrating all modules together. For instance, the fine geometrical features of the electrode mosaic pattern and the capacitor's laminated structure have been assessed through a concept of field intensification using a 2D electrostatic finite element computation. With fine geometrical features accounted for by the field intensification concept, fast electric events in capacitors can be simulated using a simple equivalent circuit model. Similar assessment of heat transfer has led to an equally efficient modelling of thermal events in capacitors

Practical Considerations of the Start-up Procedure for an Active Capacitor

DEFF Research Database (Denmark)

Wang, Haoran; Wang, Qian; Geng, Tao

2017-01-01

Capacitive DC links provide the only low-impedance current path connected with an input source during the start-up of many voltage source converters. A soft-start circuit is usually implemented to limit the inrush current. A two-terminal active capacitor is recently proposed which can directly...... replace conventional passive capacitors in DC links, with reduced cost or size for a given application. The active capacitor has the same level of convenience with two power terminals only as a passive capacitor. This paper proposes two start-up schemes for the active capacitor to overcome the drawbacks...... of existing methods previously widely used for passive capacitors. One scheme is based on a trade-off design between the start-up performance and the component sizing of the active capacitor. The other scheme is based on either an additional bypass switch together with the existing soft-start circuit...

Reliability of high-voltage pulse capacitors operating in large energy storages

International Nuclear Information System (INIS)

Kuchinskij, G.S.; Fedorova, V.S.; Shilin, O.V.

1982-01-01

To improve the reliability of pulse capacitors operating in capacitive energy storages, processes, resulting in break-down of capacitor insulation were investigated. A statistic model of failures was constructed and reliability of real capacitors, functioning at operating electric intensity Usub(oper) equal 70 kV/mm and at elevated intensity 90 kV/mm was calculated. Results of testing the IK50-ZU4 capacitor are given. The form of the capacitor service life distribution function was specified. To provide and confirm the assigned capacitor reliability, it is necessary to speed up tests at a higher voltage (1.3-1.5) Usub(oper). To improve the capacitor reliability, it is advisable to conduct acceptance tests, which include hold at increased constant voltage (1.3-1.5) Usub(oper) during 1-3 min and the effect of pulses of increased voltage (1.2-1.3) Usub(oper) with the pulse shape corresponding to operating conditions

Iodine encapsulation in CNTs and its application for electrochemical capacitor

International Nuclear Information System (INIS)

Taniguchi, Y.; Ishii, Y.; Al-zubaidi, A.; Kawasaki, S.; Rashid, M.; Syakirin, A.

2016-01-01

We report the experimental results for new type electrochemical capacitor using iodine redox reaction in single-walled carbon nanotubes (SWCNTs). It was found that the energy density of the present redox capacitor using SWCNTs is almost three times larger than that of the normal electric double layer capacitor.

Iodine encapsulation in CNTs and its application for electrochemical capacitor

Energy Technology Data Exchange (ETDEWEB)

Taniguchi, Y.; Ishii, Y.; Al-zubaidi, A.; Kawasaki, S., E-mail: kawasaki.shinji@nitech.ac.jp [Nagoya Institute of Technology, Gokiso, Showa, Nagoya, Aichi (Japan); Rashid, M.; Syakirin, A. [Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia)

2016-07-06

We report the experimental results for new type electrochemical capacitor using iodine redox reaction in single-walled carbon nanotubes (SWCNTs). It was found that the energy density of the present redox capacitor using SWCNTs is almost three times larger than that of the normal electric double layer capacitor.

Improving the mechanical stability of a standard capacitor

CSIR Research Space (South Africa)

Moodley, SS

2003-04-01

Full Text Available temperature coefficients of capacitance, they were susceptible to mechanical shock. During 1999, a project was initiated to improve the mechanical stability of the capacitors after two capacitors were damaged during transit, while being transported as separate...

Cellulose triacetate, thin film dielectric capacitor

Science.gov (United States)

Yen, Shiao-Ping S. (Inventor); Jow, T. Richard (Inventor)

1995-01-01

Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

A Decade of Shear-Wave Splitting Observations in Alaska

Science.gov (United States)

Bellesiles, A. K.; Christensen, D. H.; Abers, G. A.; Hansen, R. A.; Pavlis, G. L.; Song, X.

2010-12-01

Over the last decade four PASSCAL experiments have been conducted in different regions of Alaska. ARCTIC, BEAAR and MOOS form a north-south transect across the state, from the Arctic Ocean to Price Williams Sound, while the STEEP experiment is currently deployed to the east of that line in the St Elias Mountains of Southeastern Alaska. Shear-wave splitting observations from these networks in addition to several permanent stations of the Alaska Earthquake Information Center were determined in an attempt to understand mantle flow under Alaska in a variety of different geologic settings. Results show two dominant splitting patterns in Alaska, separated by the subducted Pacific Plate. North of the subducted Pacific Plate fast directions are parallel to the trench (along strike of the subducted Pacific Plate) indicating large scale mantle flow in the northeast-southwest direction with higher anisotropy (splitting times) within the mantle wedge. Within or below the Pacific Plate fast directions are normal to the trench in the direction of Pacific Plate convergence. In addition to these two prominent splitting patterns there are several regions that do not match either of these trends. These more complex regions which include the results from STEEP could be due to several factors including effects from the edge of the Pacific Plate. The increase of station coverage that Earthscope will bring to Alaska will aid in developing a more complete model for anisotropy and mantle flow in Alaska.

Reliability Evaluation of Base-Metal-Electrode Multilayer Ceramic Capacitors for Potential Space Applications

Science.gov (United States)

Liu, David (Donhang); Sampson, Michael J.

2011-01-01

Base-metal-electrode (BME) ceramic capacitors are being investigated for possible use in high-reliability spacelevel applications. This paper focuses on how BME capacitors construction and microstructure affects their lifetime and reliability. Examination of the construction and microstructure of commercial off-the-shelf (COTS) BME capacitors reveals great variance in dielectric layer thickness, even among BME capacitors with the same rated voltage. Compared to PME (precious-metal-electrode) capacitors, BME capacitors exhibit a denser and more uniform microstructure, with an average grain size between 0.3 and 0.5 m, which is much less than that of most PME capacitors. BME capacitors can be fabricated with more internal electrode layers and thinner dielectric layers than PME capacitors because they have a fine-grained microstructure and do not shrink much during ceramic sintering. This makes it possible for BME capacitors to achieve a very high capacitance volumetric efficiency. The reliability of BME and PME capacitors was investigated using highly accelerated life testing (HALT). Most BME capacitors were found to fail with an early avalanche breakdown, followed by a regular dielectric wearout failure during the HALT test. When most of the early failures, characterized with avalanche breakdown, were removed, BME capacitors exhibited a minimum mean time-to-failure (MTTF) of more than 105 years at room temperature and rated voltage. Dielectric thickness was found to be a critical parameter for the reliability of BME capacitors. The number of stacked grains in a dielectric layer appears to play a significant role in determining BME capacitor reliability. Although dielectric layer thickness varies for a given rated voltage in BME capacitors, the number of stacked grains is relatively consistent, typically around 12 for a number of BME capacitors with a rated voltage of 25V. This may suggest that the number of grains per dielectric layer is more critical than the

Charge retention characteristics of (Bi,La)4Ti3O12 capacitors : comparison with Pb(Zr,Ti)O3 capacitors

International Nuclear Information System (INIS)

Yoon, J. G.; Kim, D. J.; So, Y. W.

2005-01-01

We investigated the retention characteristics of (Bi,La) 4 Ti 3 O 12 (BLT) capacitors with Pt electrodes and compared them with Pb(Zr,Ti)O 3 (PZT) capacitors in the same- and opposite-state retentions. Polarization relaxations in short-time regime (t < 100 s) were well described by a power-law decay function, but the polarization relaxation of BLT was more significant than that of PZT. We discuss the difference in the relaxation process of polarization in conjunction with film microstructures and magnitudes of polarization for BLT and PZT. In long-time opposite-state retention, BLT capacitors showed much better characteristics than PZT. For both BLT and PZT, the opposite-state retention loss was governed by the development of an internal field during retention. For BLT capacitors, internal field development was much weaker than for PZT after retention, resulting in a good opposite-state retention. Structural and electrical properties are discussed in conjunction with the retention characteristics of the materials.

Degradation failure model of self-healing metallized film pulse capacitor

International Nuclear Information System (INIS)

Sun Quan; Zhong Zheng; Zhou Jinglun; Zhao Jianyin; Wei Xiaofeng; Guo Liangfu; Zhou Pizhang; Li Yizheng; Chen Dehuai

2004-01-01

The high energy density self-healing metallized film pulse capacitor has been applied to all kinds of laser facilities for their power conditioning systems, whose reliability and expense are straightforwardly affected by the reliability level of the capacitors. Based on the related research in literature, this paper analyses the degradation mechanism of the capacitor, and presents a new degradation failure model--the Gauss-Poisson model. The Gauss-Poisson model divides degradation of capacitor into naturalness degradation and outburst one. Compared with traditional Weibull failure model, the new model is more precise in evaluating the lifetime of the capacitor, and the life tests for this model are simple in design, and lower in the cost of time or expense. The Gauss-Poisson model will be a fine and widely used degradation disable model. (author)

An Active Capacitor with Self-Power and Internal Feedback Control Signals

DEFF Research Database (Denmark)

Wang, Haoran; Wang, Huai

2017-01-01

This paper proposes a concept of two-terminal active capacitor implemented by power semiconductor switches and passive elements. The active capacitor has the same level of convenience as a passive one with two power terminals only. A control strategy that does not require any external feedback...... signal is proposed and a self-power scheme for gate drivers and the controller is applied to achieve the two-terminal active capacitor. The concept, control method, self-power scheme, efficiency, and impedance characteristics of the active capacitor are presented. A case study of the proposed active...... capacitor for a capacitive DC-link application is discussed. The results reveal a significantly lower overall energy storage of passive elements and a reduced cost to fulfill a specific reliability target, compared to a passive capacitor solution. Proof-of-concept experimental results are given to verify...

Dynamics of a Liquid Dielectric Attracted by a Cylindrical Capacitor

Science.gov (United States)

Nardi, Rafael; Lemos, Nivaldo A.

2007-01-01

The dynamics of a liquid dielectric attracted by a vertical cylindrical capacitor are studied. Contrary to what might be expected from the standard calculation of the force exerted by the capacitor, the motion of the dielectric is different depending on whether the charge or the voltage of the capacitor is held constant. The problem turns out to…

Efficient IEC permanent-magnet motor (3 kW) - Final report; Effizienter IEC Permanent-Magnet-Motor (3 kW) - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Lindegger, M. [Circle Motor AG, Guemligen (Switzerland); Biner, H. P.; Evequoz, B. [Haute Ecole valaisanne, Sion (Switzerland); Salathe, D. [Hochschule Luzern, Technik und Architektur, Horw (Switzerland)

2008-04-15

Efficient permanent-magnet motors achieve in the area up to 100 kW a higher efficiency than induction machines (standard motors). A simple and fast energy saving option is the exchange of inefficient standard motors. The objective of this work is to install a 3 kW permanent-magnet motor in a standard IEC housing and the optimization of the design for high efficiency. Another objective is the development and the realization of an efficient variable speed control. The efficiency of the motor and the inverter with the control system must be demonstrated by tests. These tasks have been split between Circle Motor AG and the universities of applied sciences of Valais and Lucerne. Considering high-efficiency and low manufacturing cost, a brushless DC solution was adopted. This resulted in an optimum design of the motor and the control system realized with a three-phase rectifier, a buck converter with variable DC voltage, and a three-phase inverter feeding full positive and negative current to two of the legs simultaneously. The maximum measured efficiency is about 96.5% for the inverter and 92% for the motor. With the advantage of the variable speed operation, the efficiency of the realized 3 kW permanent magnet motor together with the control system is always higher than the efficiency of a measured class EFF1 induction motor, even with a direct connection to the grid. The permanent-magnet motor is also about 10 kg lighter. The cost calculation shows that the permanent-magnet motor can be competitive with the induction motor when speed control is desired. This is also the domain with the largest potential for energy savings from variable speed pumps, compressors, fans. (author)

Experimental analysis of an MIM capacitor with a concave shield

International Nuclear Information System (INIS)

Liu Lintao; Yu Mingyan; Wang Jinxiang

2009-01-01

A novel shielding scheme is developed by inserting a concave shield between a metal-insulator-metal (MIM) capacitor and the silicon substrate. Chip measurements reveal that the concave shield improves the quality factor by 11% at 11.8 GHz and 14% at 18.8 GHz compared with an unshielded MIM capacitor. It also alleviates the effect on shunt capacitance between the bottom plate of the MIM capacitor and the shield layer. Moreover, because the concave shields simplify substrate modeling, a simple circuit model of the MIM capacitor with concave shield is presented for radio frequency applications.

Trench capacitor and method for producing the same

NARCIS (Netherlands)

2009-01-01

A method of fabricating a trench capacitor, and a trench capacitor fabricated thereby, are disclosed. The method involves the use of a vacuum impregnation process for a sol-gel film, to facilitate effective deposition of high- permittivity materials within a trench in a semiconductor substrate, to

Charging damage in floating metal-insulator-metal capacitors

NARCIS (Netherlands)

Ackaert, Jan; Wang, Zhichun; De Backer, E.; Coppens, P.

2002-01-01

In this paper, charging induced damage (CID) to metal-insulator-metal capacitors (MIMC) is reported. The damage is caused by the build up of a voltage potential difference between the two plates of the capacitor. A simple logarithmic relation is discovered between the damage by this voltage

Clocking Scheme for Switched-Capacitor Circuits

DEFF Research Database (Denmark)

Steensgaard-Madsen, Jesper

1998-01-01

A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed.......A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed....

Cracking Problems and Mechanical Characteristics of PME and BME Ceramic Capacitors

Science.gov (United States)

Teverovsky, Alexander

2018-01-01

Most failures in MLCCs are caused by cracking that create shorts between opposite electrodes of the parts. A use of manual soldering makes this problem especially serious for space industry. Experience shows that different lots of ceramic capacitors might have different susceptibility to cracking under manual soldering conditions. This simulates a search of techniques that would allow revealing capacitors that are most robust to soldering-induced stresses. Currently, base metal electrode (BME) capacitors are introduced to high-reliability applications as a replacement of precious metal electrode (PME) parts. Understanding the difference in the susceptibility to cracking between PME and BME capacitors would facilitate this process. This presentation gives a review of mechanical characteristics measured in-situ on MLCCs that includes flexural strength, Vickers hardness, indentation fracture toughness, and the board flex testing and compare characteristics of BME and PME capacitors. A history case related to cracking in PME capacitors that caused flight system malfunctions and mechanisms of failure are considered. Possible qualification tests that would allow evaluation of the resistance of MLCCs to manual soldering are suggested and perspectives related to introduction of BME capacitors discussed.

Stretchable Dual-Capacitor Multi-Sensor for Touch-Curvature-Pressure-Strain Sensing.

Science.gov (United States)

Jin, Hanbyul; Jung, Sungchul; Kim, Junhyung; Heo, Sanghyun; Lim, Jaeik; Park, Wonsang; Chu, Hye Yong; Bien, Franklin; Park, Kibog

2017-09-07

We introduce a new type of multi-functional capacitive sensor that can sense several different external stimuli. It is fabricated only with polydimethylsiloxane (PDMS) films and silver nanowire electrodes by using selective oxygen plasma treatment method without photolithography and etching processes. Differently from the conventional single-capacitor multi-functional sensors, our new multi-functional sensor is composed of two vertically-stacked capacitors (dual-capacitor). The unique dual-capacitor structure can detect the type and strength of external stimuli including curvature, pressure, strain, and touch with clear distinction, and it can also detect the surface-normal directionality of curvature, pressure, and touch. Meanwhile, the conventional single-capacitor sensor has ambiguity in distinguishing curvature and pressure and it can detect only the strength of external stimulus. The type, directionality, and strength of external stimulus can be determined based on the relative capacitance changes of the two stacked capacitors. Additionally, the logical flow reflected on a tree structure with its branches reaching the direction and strength of the corresponding external stimulus unambiguously is devised. This logical flow can be readily implemented in the sensor driving circuit if the dual-capacitor sensor is commercialized actually in the future.

Capacitance-voltage characterization of fully silicided gated MOS capacitor

International Nuclear Information System (INIS)

Wang Baomin; Ru Guoping; Jiang Yulong; Qu Xinping; Li Bingzong; Liu Ran

2009-01-01

This paper investigates the capacitance-voltage (C-V) measurement on fully silicided (FUSI) gated metal-oxide-semiconductor (MOS) capacitors and the applicability of MOS capacitor models. When the oxide leakage current of an MOS capacitor is large, two-element parallel or series model cannot be used to obtain its real C-V characteristic. A three-element model simultaneously consisting of parallel conductance and series resistance or a four-element model with further consideration of a series inductance should be used. We employed the three-element and the four-element models with the help of two-frequency technique to measure the Ni FUSI gated MOS capacitors. The results indicate that the capacitance of the MOS capacitors extracted by the three-element model still shows some frequency dispersion, while that extracted by the four-element model is close to the real capacitance, showing little frequency dispersion. The obtained capacitance can be used to calculate the dielectric thickness with quantum effect correction by NCSU C-V program. We also investigated the influence of MOS capacitor's area on the measurement accuracy. The results indicate that the decrease of capacitor area can reduce the dissipation factor and improve the measurement accuracy. As a result, the frequency dispersion of the measured capacitance is significantly reduced, and real C-V characteristic can be obtained directly by the series model. In addition, this paper investigates the quasi-static C-V measurement and the photonic high-frequency C-V measurement on Ni FUSI metal gated MOS capacitor with a thin leaky oxide. The results indicate that the large tunneling current through the gate oxide significantly perturbs the accurate measurement of the displacement current, which is essential for the quasi-static C-V measurement. On the other hand, the photonic high-frequency C-V measurement can bypass the leakage problem, and get reliable low-frequency C-V characteristic, which can be used to

Transmission Line Resonator Segmented with Series Capacitors

DEFF Research Database (Denmark)

Zhurbenko, Vitaliy; Boer, Vincent; Petersen, Esben Thade

2016-01-01

Transmission line resonators are often used as coils in high field MRI. Due to distributed nature of such resonators, coils based on them produce inhomogeneous field. This work investigates application of series capacitors to improve field homogeneity along the resonator. The equations for optimal...... values of evenly distributed capacitors are presented. The performances of the segmented resonator and a regular transmission line resonator are compared....

Graphene double-layer capacitor with ac line-filtering performance.

Science.gov (United States)

Miller, John R; Outlaw, R A; Holloway, B C

2010-09-24

Electric double-layer capacitors (DLCs) can have high storage capacity, but their porous electrodes cause them to perform like resistors in filter circuits that remove ripple from rectified direct current. We have demonstrated efficient filtering of 120-hertz current with DLCs with electrodes made from vertically oriented graphene nanosheets grown directly on metal current collectors. This design minimized electronic and ionic resistances and produced capacitors with RC time constants of less than 200 microseconds, in contrast with ~1 second for typical DLCs. Graphene nanosheets have a preponderance of exposed edge planes that greatly increases charge storage as compared with that of designs that rely on basal plane surfaces. Capacitors constructed with these electrodes could be smaller than the low-voltage aluminum electrolyte capacitors that are typically used in electronic devices.

Graphene Double-Layer Capacitor with ac Line-Filtering Performance

Science.gov (United States)

Miller, John R.; Outlaw, R. A.; Holloway, B. C.

2010-09-01

Electric double-layer capacitors (DLCs) can have high storage capacity, but their porous electrodes cause them to perform like resistors in filter circuits that remove ripple from rectified direct current. We have demonstrated efficient filtering of 120-hertz current with DLCs with electrodes made from vertically oriented graphene nanosheets grown directly on metal current collectors. This design minimized electronic and ionic resistances and produced capacitors with RC time constants of less than 200 microseconds, in contrast with ~1 second for typical DLCs. Graphene nanosheets have a preponderance of exposed edge planes that greatly increases charge storage as compared with that of designs that rely on basal plane surfaces. Capacitors constructed with these electrodes could be smaller than the low-voltage aluminum electrolyte capacitors that are typically used in electronic devices.

Catechol-chitosan redox capacitor for added amplification in electrochemical immunoanalysis.

Science.gov (United States)

Yan, Kun; Liu, Yi; Guan, Yongguang; Bhokisham, Narendranath; Tsao, Chen-Yu; Kim, Eunkyoung; Shi, Xiao-Wen; Wang, Qin; Bentley, William E; Payne, Gregory F

2018-05-22

Antibodies are common recognition elements for molecular detection but often the signals generated by their stoichiometric binding must be amplified to enhance sensitivity. Here, we report that an electrode coated with a catechol-chitosan redox capacitor can amplify the electrochemical signal generated from an alkaline phosphatase (AP) linked immunoassay. Specifically, the AP product p-aminophenol (PAP) undergoes redox-cycling in the redox capacitor to generate amplified oxidation currents. We estimate an 8-fold amplification associated with this redox-cycling in the capacitor (compared to detection by a bare electrode). Importantly, this capacitor-based amplification is generic and can be coupled to existing amplification approaches based on enzyme-linked catalysis or magnetic nanoparticle-based collection/concentration. Thus, the capacitor should enhance sensitivities in conventional immunoassays and also provide chemical to electrical signal transduction for emerging applications in molecular communication. Copyright © 2018 Elsevier B.V. All rights reserved.

Problems of increasing specific characteristics of pulse capacitors and cables

International Nuclear Information System (INIS)

Kuchinskij, G.S.; Monastyrskij, A.E.; Shilin, O.V.

1984-01-01

Requirements for high specific energy are practically related to all types of pulse capacitors of energy storage. At present the specific energy for most types of home and foreign pulse capacitors is about 0.1 MJ/m 3 at operating electric field intensity 70-100 kV/mm. It is shown that the basic means for increasing the specific energy and working intensity is the application of new polymeric film materials. Application of paper-film and film insulation permits to develop the specific types of capacitors designed for a limited service life in an aperiodic discharge mode with lower reliabiliy and the specific energy upto 0.5 MJ/m 3 . Characteristics of separate types of pulse capacitors and cables are given, and reliability criterion is considered. Measures of increasing reliability and service life for pulse capacitors and cables, used as tokamak power supplies are enumerated

Absorption Voltages and Insulation Resistance in Ceramic Capacitors with Cracks

Science.gov (United States)

Teverovsky, Alexander

2016-01-01

Time dependence of absorption voltages (Vabs) in different types of low-voltage X5R and X7R ceramic capacitors was monitored for a maximum duration of hundred hours after polarization. To evaluate the effect of mechanical defects on Vabs, cracks in the dielectric were introduced either mechanically or by thermal shock. The maximum absorption voltage, time to roll-off, and the rate of voltage decrease are shown to depend on the crack-related leakage currents and insulation resistance in the parts. A simple model that is based on the Dow equivalent circuit for capacitors with absorption has been developed to assess the insulation resistance of capacitors. Standard measurements of the insulation resistance, contrary to the measurements based on Vabs, are not sensitive to the presence of mechanical defects and fail to reveal capacitors with cracks. Index Terms: Ceramic capacitor, insulation resistance, dielectric absorption, cracking.

The two-capacitor problem revisited: a mechanical harmonic oscillator model approach

International Nuclear Information System (INIS)

Lee, Keeyung

2009-01-01

The well-known two-capacitor problem, in which exactly half the stored energy disappears when a charged capacitor is connected to an identical capacitor, is discussed based on the mechanical harmonic oscillator model approach. In the mechanical harmonic oscillator model, it is shown first that exactly half the work done by a constant applied force is dissipated irrespective of the form of dissipation mechanism when the system comes to a new equilibrium after a constant force is abruptly applied. This model is then applied to the energy loss mechanism in the capacitor charging problem or the two-capacitor problem. This approach allows a simple explanation of the energy dissipation mechanism in these problems and shows that the dissipated energy should always be exactly half the supplied energy whether that is caused by the Joule heat or by the radiation. This paper, which provides a simple treatment of the energy dissipation mechanism in the two-capacitor problem, is suitable for all undergraduate levels

Atomic Layer Deposition Alumina-Passivated Silicon Nanowires: Probing the Transition from Electrochemical Double-Layer Capacitor to Electrolytic Capacitor.

Science.gov (United States)

Gaboriau, Dorian; Boniface, Maxime; Valero, Anthony; Aldakov, Dmitry; Brousse, Thierry; Gentile, Pascal; Sadki, Said

2017-04-19

Silicon nanowires were coated by a 1-5 nm thin alumina layer by atomic layer deposition (ALD) in order to replace poorly reproducible and unstable native silicon oxide by a highly conformal passivating alumina layer. The surface coating enabled probing the behavior of symmetric devices using such electrodes in the EMI-TFSI electrolyte, allowing us to attain a large cell voltage up to 6 V in ionic liquid, together with very high cyclability with less than 4% capacitance fade after 10 6 charge/discharge cycles. These results yielded fruitful insights into the transition between an electrochemical double-layer capacitor behavior and an electrolytic capacitor behavior. Ultimately, thin ALD dielectric coatings can be used to obtain hybrid devices exhibiting large cell voltage and excellent cycle life of dielectric capacitors, while retaining energy and power densities close to the ones displayed by supercapacitors.

Degradation Effect on Reliability Evaluation of Aluminum Electrolytic Capacitor in Backup Power Converter

DEFF Research Database (Denmark)

Zhou, Dao; Wang, Huai; Blaabjerg, Frede

2017-01-01

DC capacitors in power electronic converters are a major constraint on improvement of power density as well as reliability. In this paper, according to the degradation data of electrolytic capacitors through the accelerated test, the time-to-failure of the capacitor cell is acquired and it can...... be further extended to lower stress levels. Then, in a case study of a fuel cell backup power application, the mission profile based lifetime expectancy of the individual capacitor and the capacitor bank is estimated in terms of the standby mode and operation mode. The lifetime prediction of the capacitor...

Simulation and analysis of transient over voltages due to capacitor banks switching

International Nuclear Information System (INIS)

Jadid, Sh.; Yazdanpanah, D.

2002-01-01

The switching of any capacitor bank produces over voltages. Transient overvoltage will always occur in the switching device, the switching of shunt capacitor bank has become the most common source of transient voltage on power systems. Transient over voltages due to switching the capacitor bands hurt not only to the capacitor banks, but also to other equipment, such as circuit breakers and transformers. Several methods are available for reducing energising transients. These devices include pre-insertion resistors, pre-insertion inductors,synchronous closing, and MOV arresters. However, not all are practical or economical. The other important problem is existence of capacitor banks in presence of harmonics.Capacitors do not produce harmonics;however,the addition of capacitors to the electrical system will change the frequency response characteristics of the system will change the frequency response characteristics of the system, and in some cases can result in magnification of the voltage and current distortion in the system. In other word in presence of harmonic-producing loads,the capacitors used for power factor correction,may cause parallel resonance with the system inductance, so they increase the total harmonic distortion of voltage and current waveforms

SOGI-based capacitor voltage feedback active damping in LCL-filtered grid converters

DEFF Research Database (Denmark)

Xin, Zhen; Wang, Xiongfei; Loh, Poh Chiang

2015-01-01

The capacitor voltage feedback active damping control is an attractive way to suppress LCL-filter resonance especially for the systems where the capacitor voltage is used for grid synchronization, since no extra sensors are added. The derivative is the core of the capacitor voltage feedback active...... derivative is more suited for capacitor voltage feedback active damping control. Experimental results validate the effectiveness of the proposed method....

Electrode/Dielectric Strip For High-Energy-Density Capacitor

Science.gov (United States)

Yen, Shiao-Ping S.

1994-01-01

Improved unitary electrode/dielectric strip serves as winding in high-energy-density capacitor in pulsed power supply. Offers combination of qualities essential for high energy density: high permittivity of dielectric layers, thinness, and high resistance to breakdown of dielectric at high electric fields. Capacitors with strip material not impregnated with liquid.

Reliability of Capacitors for DC-Link Applications in Power Electronic Converters

DEFF Research Database (Denmark)

Wang, Huai; Blaabjerg, Frede

2014-01-01

DC-link capacitors are an important part in the majority of power electronic converters which contribute to cost, size and failure rate on a considerable scale. From capacitor users' viewpoint, this paper presents a review on the improvement of reliability of dc link in power electronic converters...... from two aspects: 1) reliability-oriented dc-link design solutions; 2) conditioning monitoring of dc-link capacitors during operation. Failure mechanisms, failure modes and lifetime models of capacitors suitable for the applications are also discussed as a basis to understand the physics......-of-failure. This review serves to provide a clear picture of the state-of-the-art research in this area and to identify the corresponding challenges and future research directions for capacitors and their dc-link applications....

Single ICCII Sinusoidal Oscillators Employing Grounded Capacitors

Directory of Open Access Journals (Sweden)

J. W. Horng

2011-09-01

Full Text Available Two inverting second-generation current conveyors (ICCII based sinusoidal oscillators are presented. The first sinusoidal oscillator is composed of one ICCII, two grounded capacitors and two resistors. The oscillation condition and oscillation frequency can be orthogonally controllable. The second sinusoidal oscillator is composed of one ICCII, two grounded capacitors and three resistors. The oscillation condition and oscillation frequency can be independently controllable through different resistors.

Impedance measurement and modelling of super-capacitors for railway applications

Energy Technology Data Exchange (ETDEWEB)

Hammar, A.; Chabas, J. [Societe Nationale des Chemins de fer Francais (SNCF), Dir. de la Recherche, 75 - Paris (France); Coquery, G.; Lallemand, R. [Institut National de Recherche sur les Transports et leur Securite (INRETS), Lab. des Technologies Nouvelles, 94 - Arcueil (France); Rojat, G.; Venet, P. [Lyon-1 Univ. Claude Bernard, CEGELY, 69 - Villeurbanne (France)

2004-07-01

Railways and electrical traction systems require high power rates to achieve their operating performances. Systems of power supply based on super-capacitors should offer high power density along with good energy efficiency and expected operating safety. We investigate general behaviours of super-capacitors with two powerful methods of analysis. The first is constant charge/discharge current at high level value (500 A), the second is impedance spectroscopy which leads to the acquisition of a set of parameters that are considered sufficient to describe general properties of super-capacitor, in particular the state of health and the available energy in any operating conditions. An electrical circuit model is defined for super-capacitors based on activated carbon and organic electrolyte. It takes into account the dependence of super-capacitor to voltage and current. The mixture of data of the two methods permits to obtain a representative model for power applications. Matlab/Simulink simulations are shown to verify the validity of the model. (authors)

Capacitor voltage ripple reduction and arm energy balancing in MMC-HVDC

DEFF Research Database (Denmark)

Parikh, Harsh; Martin-Loeches, Ruben Sánches; Tsolaridis, Georgios

2016-01-01

Modular Multilevel Converters are emerging and widely used in HVDC applications. However, the submodule capacitors are still large and the energy balancing under unbalanced conditions is a challenge. In this paper, an analytical model focusing on the energy stored in the capacitors and voltage...... variations is utilized in order to achieve better performance. By injecting a second order harmonic component into the circulating current, the energy variation and consequently the capacitor voltage ripple is reduced allowing for a capacitor size reduction. At the same time, an arm energy balancing...

Capacitor Bank 'CHANDI' for Plasma Target Production for Liner Plasma Interaction

International Nuclear Information System (INIS)

Shukla, R.; Sharma, S.K.; Debnath, K.; Shyam, A.

2006-01-01

A capacitor bank is fabricated to drive (JXB) Plasma gun to generate hot plasma (target) for liner plasma investigation. The bank will also be used for driving other pintch experiments. The bank consists of 8 capacitors connected in parallel, each having capacitance of 178 μF giving a total of 1424uF. The bank is charged at 15 kV using a 28 kV power supply charging the capacitors in 65 seconds utilizing full wave charging technique. The total energy of the bank is 160kJ at 15kV. A modeling of power supply was done so that all the components involved are utilized to their operating limit safely. Moreover to give fault protection to the capacitor bank we have implemented the neutral control technique in the power supply. The capacitor bank is discharged to the inductive load through an ignitron switch of very high coulomb rating and capable of withstanding high voltages at its electrodes. The cables used for connecting capacitor bank with ignitron switch are used in parallel to give them collective capability of bearing capacitor discharge currents. These cables are capable of holding high DC voltages (40kV), which appear at the time of charging of the bank. The bank is tested and is operational

Antenna Miniaturization with MEMS Tunable Capacitors

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

2014-01-01

In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss and their characterist......In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss...

SplitDist—Calculating Split-Distances for Sets of Trees

DEFF Research Database (Denmark)

Mailund, T

2004-01-01

We present a tool for comparing a set of input trees, calculating for each pair of trees the split-distances, i.e., the number of splits in one tree not present in the other.......We present a tool for comparing a set of input trees, calculating for each pair of trees the split-distances, i.e., the number of splits in one tree not present in the other....

High-energy power capacitors, their applied technology and the trends

International Nuclear Information System (INIS)

2012-01-01

High-voltage and high-energy-density power capacitors called high-power ones such as film or electrolytic capacitors, have been used in large quantities for the pulse power technology such as an impulse current or voltage generator and a laser power supply, and for the power electronics one with progress of the power semiconductor device and the inverter technology. Recently, electric double layer capacitors (EDLC) with remarkable technical progress have been applied for the equipments of electric power and industrial field for the purpose of energy saving or electric power quality improvement, which have come to link to the electric power system. Thus, using a lot of high-power capacitors near our life would require to know the structure, the principle and the characteristic of capacitors, and also to consider suitable directions for use, maintenance and safety and so on, when carrying out a system and a facility design. In the technical report, while describing the dielectric and the feature of some high-power capacitors, and introducing the application examples to the laser-fusion power supply and some systems with EDLC, the trend of standardization of EDLC and the directivity of the examination about installation and maintenance of the applied equipments are described. (author)

Instantaneous thermal modeling of the DC-link capacitor in PhotoVoltaic systems

DEFF Research Database (Denmark)

Yang, Yongheng; Ma, Ke; Wang, Huai

2015-01-01

, instantaneous thermal modeling approaches considering mission profiles for the DC-link capacitor in single-phase PV systems are explored in this paper. These thermal modelling approaches are based on: a) fast Fourier transform, b) look-up tables, and c) ripple current reconstruction. Moreover, the thermal...... grid-connected PV system have been adopted to demonstrate a look-up table based modelling approach, where real-field daily ambient conditions are considered....... modelling approaches for the DC-link capacitors take into account the instantaneous thermal characteristics, which are more challenging to the capacitor reliability during operation. Such instantaneous thermal modeling approaches enable a translation of instantaneous capacitor power losses to capacitor...

Nanodomain Engineering in Ferroelectric Capacitors with Graphene Electrodes.

Science.gov (United States)

Lu, Haidong; Wang, Bo; Li, Tao; Lipatov, Alexey; Lee, Hyungwoo; Rajapitamahuni, Anil; Xu, Ruijuan; Hong, Xia; Farokhipoor, Saeedeh; Martin, Lane W; Eom, Chang-Beom; Chen, Long-Qing; Sinitskii, Alexander; Gruverman, Alexei

2016-10-12

Polarization switching in ferroelectric capacitors is typically realized by application of an electrical bias to the capacitor electrodes and occurs via a complex process of domain structure reorganization. As the domain evolution in real devices is governed by the distribution of the nucleation centers, obtaining a domain structure of a desired configuration by electrical pulsing is challenging, if not impossible. Recent discovery of polarization reversal via the flexoelectric effect has opened a possibility for deterministic control of polarization in ferroelectric capacitors. In this paper, we demonstrate mechanical writing of arbitrary-shaped nanoscale domains in thin-film ferroelectric capacitors with graphene electrodes facilitated by a strain gradient induced by a tip of an atomic force microscope (AFM). A phase-field modeling prediction of a strong effect of graphene thickness on the threshold load required to initiate mechanical switching has been confirmed experimentally. Deliberate voltage-free domain writing represents a viable approach for development of functional devices based on domain topology and electronic properties of the domains and domain walls.

The Two-Capacitor Problem Revisited: A Mechanical Harmonic Oscillator Model Approach

Science.gov (United States)

Lee, Keeyung

2009-01-01

The well-known two-capacitor problem, in which exactly half the stored energy disappears when a charged capacitor is connected to an identical capacitor, is discussed based on the mechanical harmonic oscillator model approach. In the mechanical harmonic oscillator model, it is shown first that "exactly half" the work done by a constant applied…

Reliability assessment for metallized film pulse capacitors with accelerated degradation test

International Nuclear Information System (INIS)

Zhao Jianyin; Liu Fang; Xi Wenjun; He Shaobo; Wei Xiaofeng

2011-01-01

The high energy density self-healing metallized film pulse capacitor has been applied to all kinds of laser facilities for their power conditioning systems, whose reliability is straightforward affected by the reliability level of capacitors. Reliability analysis of highly reliable devices, such as metallized film capacitors, is a challenge due to cost and time restriction. Accelerated degradation test provides a way to predict its life cost and time effectively. A model and analyses for accelerated degradation data of metallized film capacitors are described. Also described is a method for estimating the distribution of failure time. The estimation values of the unknown parameters in this model are 9.066 9 x 10 -8 and 0.022 1. Both the failure probability density function (PDF) and the cumulative distribution function (CDF) can be presented by this degradation failure model. Based on these estimation values and the PDF/CDF, the reliability model of the metallized film capacitors is obtained. According to the reliability model, the probability of the capacitors surviving to 20 000 shot is 0.972 4. (authors)

Characterization system for research on energy storage capacitors

Science.gov (United States)

Noriega, J. R.; Iyore, O. D.; Budime, C.; Gnade, B.; Vasselli, J.

2013-05-01

In this work a characterization system for high energy-density capacitors is described and demonstrated. Capacitors are being designed using thin-film technology in an attempt to achieve higher energy-density levels by operating the devices at a high voltage. These devices are fabricated from layers of 100 nm aluminum and a layer of polyvinylidene fluoride-hexafluoropropylene on a polyethylene naphthalate plastic substrate. The devices have been designed to store electrical charge at up to 200 V. Characterizations of these devices focus on the measurement of capacitance vs bias voltage and temperature, equivalent series resistance, and charge/discharge cycles. For the purpose of the characterization of these capacitors, an electronic charge/discharge interface was designed and tested.

Two-layer radio frequency MEMS fractal capacitors in PolyMUMPS for S-band applications

KAUST Repository

Elshurafa, Amro M.

2012-07-23

In this Letter, the authors fabricate for the first time MEMS fractal capacitors possessing two layers and compare their performance characteristics with the conventional parallel-plate capacitor and previously reported state-of-the-art single-layer MEMS fractal capacitors. Explicitly, a capacitor with a woven structure and another with an interleaved configuration were fabricated in the standard PolyMUMPS surface micromachining process and tested at S-band frequencies. The self-resonant frequencies of the fabricated capacitors were close to 10GHz, which is better than that of the parallel-plate capacitor, which measured only 5.5GHz. Further, the presented capacitors provided a higher capacitance when compared with the state-of-the-art-reported MEMS fractal capacitors created using a single layer at the expense of a lower quality factor. © 2012 The Institution of Engineering and Technology.

Highly Accurate Derivatives for LCL-Filtered Grid Converter with Capacitor Voltage Active Damping

DEFF Research Database (Denmark)

Xin, Zhen; Loh, Poh Chiang; Wang, Xiongfei

2016-01-01

The middle capacitor voltage of an LCL-filter, if fed back for synchronization, can be used for active damping. An extra sensor for measuring the capacitor current is then avoided. Relating the capacitor voltage to existing popular damping techniques designed with capacitor current feedback would...... are then proposed, based on either second-order or non-ideal generalized integrator. Performances of these derivatives have been found to match the ideal “s” function closely. Active damping based on capacitor voltage feedback can therefore be realized accurately. Experimental results presented have verified...

DC-to-DC converter comprising a reconfigurable capacitor unit

NARCIS (Netherlands)

2008-01-01

The present invention relates to a configurable trench multi-capacitor device comprising a trench in a semiconductor substrate. The trench has a lateral extension exceeding 10 micrometer and a trench filling includes a number of at least four electrically conductive capacitor-electrode layers. A

DC-to-DC converter comprising a reconfigurable capacitor unit

NARCIS (Netherlands)

Klootwijk, J.H.; Bergveld, H.J.; Roozeboom, F.; Reefman, D.; Ruigrok, J.

2013-01-01

The present invention relates to a configurable trench multi-capacitor device comprising a trench in a semiconductor substrate. The trench has a lateral extension exceeding 10 micrometer and a trench filling includes a number of at least four electrically conductive capacitor-electrode layers. A

Floating body cell a novel capacitor-less DRAM cell

CERN Document Server

Ohsawa, Takashi

2011-01-01

DRAM together with NAND Flash is driving semiconductor technologies with wide spectrum of usage ranging from PC, mobile phone and digital home appliances to solid-state disk (SSD). However, the DRAM cell which consists of a data storage capacitor (1C) and a switching transistor (1T) is facing serious difficulty in shrinking the size of the capacitor whose capacitance needs to be kept almost constant (20~30fF) throughout generations. The availability of a new DRAM cell which does not rely on an explicit capacitor for storing its data is more than ever awaited for further increasing the bit dens

Investigation of embedded perovskite nanoparticles for enhanced capacitor permittivities.

Science.gov (United States)

Krause, Andreas; Weber, Walter M; Pohl, Darius; Rellinghaus, Bernd; Verheijen, Marcel; Mikolajick, Thomas

2014-11-26

Growth experiments show significant differences in the crystallization of ultrathin CaTiO3 layers on polycrystalline Pt surfaces. While the deposition of ultrathin layers below crystallization temperature inhibits the full layer crystallization, local epitaxial growth of CaTiO3 crystals on top of specific oriented Pt crystals occurs. The result is a formation of crystals embedded in an amorphous matrix. An epitaxial alignment of the cubic CaTiO3 ⟨111⟩ direction on top of the underlying Pt {111} surface has been observed. A reduced forming energy is attributed to an interplay of surface energies at the {111} interface of both materials and CaTiO3 nanocrystallites facets. The preferential texturing of CaTiO3 layers on top of Pt has been used in the preparation of ultrathin metal-insulator-metal capacitors with 5-30 nm oxide thickness. The effective CaTiO3 permittivity in the capacitor stack increases to 55 compared to capacitors with amorphous layers and a permittivity of 28. The isolated CaTiO3 crystals exhibit a passivation of the CaTiO3 grain surfaces by the surrounding amorphous matrix, which keeps the capacitor leakage current at ideally low values comparable for those of amorphous thin film capacitors.

The design of a small linear-resonant, split Stirling cryogenic refrigerator compressor

Science.gov (United States)

Ackermann, R. A.

1985-01-01

The development of a small linear-resonant compressor for use in a 1/4-watt, 78K, split Stirling cryogenic refrigerator is discussed. The compressor contains the following special features: (1) a permanent-magnet linear motor; (2) resonant dynamics; (3) dynamic balancing; and (4) a close-clearance seal between the compressor piston and cylinder. This paper describes the design of the compressor, and presents component test data and system test data for the compressor driving a 1/4-watt expander.

Carbon-based fibrous EDLC capacitors and supercapacitors

OpenAIRE

Lekakou, C; Moudam, O; Markoulidis, F; Andrews, T; Watts, JF; Reed, GT

2011-01-01

This paper investigates electrochemical double-layer capacitors (EDLCs) including two alternative types of carbon-based fibrous electrodes, a carbon fibre woven fabric (CWF) and a multiwall carbon nanotube (CNT) electrode, as well as hybrid CWF-CNT electrodes. Two types of separator membranes were also considered. An organic gel electrolyte PEO-LiCIO4-EC-THF was used to maintain a high working voltage. The capacitor cells were tested in cyclic voltammetry, charge-discharge, and impedance test...

Phase shift PWM with double two-switch bridge for high power capacitor charging

International Nuclear Information System (INIS)

Karandikar, U.S.; Singh, Yashpal; Thakurta, A.C.

2013-01-01

Pulse power supply systems working at higher voltage and high repetition rate demands for higher power from capacitor chargers. Capacitor charging requirement become more challenging in such cases. In pulse power circuits, energy storage capacitor should be charged to its desired voltage before the next switching occurs. It is discharged within a small time, delivering large pulse power. A capacitor charger has to work with wide load variation repeatedly. Many schemes are used for this purpose. The proposed scheme aims at reducing stresses on switches by reducing peak current and their evils. A high voltage power supply is designed for capacitor charging. The proposed scheme is based on a Phase-Shifted PWM without using any extra component to achieve soft switching. Indirect constant average current capacitor charging is achieved with a simple control scheme. A double two-switch bridge is proposed to enhance reliability. Power supply has been developed to charge a capacitor of 50 μF to 2.5 kV at 25 Hz. (author)

Downhole transmission system comprising a coaxial capacitor

Science.gov (United States)

Hall, David R [Provo, UT; Pixton, David S [Lehi, UT; Johnson, Monte L [Orem, UT; Bartholomew, David B [Springville, UT; Hall, Jr., H. Tracy; Rawle, Michael [Springville, UT

2011-05-24

A transmission system in a downhole component comprises a plurality of data transmission elements. A coaxial cable having an inner conductor and an outer conductor is disposed within a passage in the downhole component such that at least one capacitor is disposed in the passage and having a first terminal coupled to the inner conductor and a second terminal coupled to the outer conductor. Preferably the transmission element comprises an electrically conducting coil. Preferably, within the passage a connector is adapted to electrically connect the inner conductor of the coaxial cable and the lead wire. The coaxial capacitor may be disposed between and in electrically communication with the connector and the passage. In another embodiment a connector is adapted to electrical connect a first and a second portion of the inner conductor of the coaxial cable and a coaxial capacitor is in electrical communication with the connector and the passage.

Powder based superdielectric materials for novel Capacitor design

Science.gov (United States)

2017-06-01

found in cars, smartphones and other devices have adequate energy densities but lack optimal electric power delivery performance [4]. Stated differently... physical damage to the electrodes [5]. Conversely, capacitors store energy electrostatically by releasing excited state electrons collected on a...overview of capacitor theory is presented as a means of highlighting key physics principles applicable to this research. First, the concept of

The application of structural nonlinearity in the development of linearly tunable MEMS capacitors

International Nuclear Information System (INIS)

Shavezipur, M; Khajepour, A; Hashemi, S M

2008-01-01

Electrostatically actuated parallel-plate tunable capacitors are the most desired MEMS capacitors because of their smaller sizes and higher Q-factors. However, these capacitors suffer from low tunability and exhibit high sensitivity near the pull-in voltage which counters the concept of tunability. In this paper, a novel design for parallel-plate tunable capacitors with high tunability and linear capacitance–voltage (C–V) response is developed. The design uses nonlinear structural rigidities to relieve intrinsic electrostatic nonlinearity in MEMS capacitors. Based on the force–displacement characteristic of an ideally linear capacitor, a real beam-like nonlinear spring model is developed. The variable stiffness coefficients of such springs improve the linearity of the C–V curve. Moreover, because the structural stiffness increases with deformations, the pull-in is delayed and higher tunability is achieved. Finite element simulations reveal that capacitors with air gaps larger than 4 µm and supporting beams thinner than 1 µm can generate highly linear C–V responses and tunabilities over 120%. Experimental results for capacitors fabricated by PolyMUMPs verify the effect of weak nonlinear geometric stiffness on improving the tunability for designs with a small air gap and relatively thick structural layers

Impedance Characteristics Modeling of a Two-Terminal Active Capacitor

DEFF Research Database (Denmark)

Wang, Haoran; Wang, Huai; Lu, Minghui

2017-01-01

to overcome the above issues. In this paper, the modeling of the active capacitor is investigated and a voltage feed-forward compensation scheme is proposed for overshoot reduction. Therefore, the impedance, equivalent capacitance, ESR, and ESL, of the active capacitor can be specified. A case study based...

Reversible post-breakdown conduction in aluminum oxide-polymer capacitors

NARCIS (Netherlands)

Chen, Qian; Gomes, H.L.; Rocha, P.R.F.; Leeuw, de D.M.; Meskers, S.C.J.

2013-01-01

Aluminum/Al2O3/polymer/metal capacitors submitted to a low-power constant current stress undergo dielectric breakdown. The post-breakdown conduction is metastable, and over time the capacitors recover their original insulating properties. The decay of the conduction with time follows a power law

Barium titanate nanocomposite capacitor FY09 year end report.

Energy Technology Data Exchange (ETDEWEB)

Stevens, Tyler E.; DiAntonio, Christopher Brian; Yang, Pin; Chavez, Tom P.; Winter, Michael R.; Monson, Todd C.; Roesler, Alexander William; Fellows, Benjamin D.

2009-11-01

This late start RTBF project started the development of barium titanate (BTO)/glass nanocomposite capacitors for future and emerging energy storage applications. The long term goal of this work is to decrease the size, weight, and cost of ceramic capacitors while increasing their reliability. Ceramic-based nanocomposites have the potential to yield materials with enhanced permittivity, breakdown strength (BDS), and reduced strain, which can increase the energy density of capacitors and increase their shot life. Composites of BTO in glass will limit grain growth during device fabrication (preserving nanoparticle grain size and enhanced properties), resulting in devices with improved density, permittivity, BDS, and shot life. BTO will eliminate the issues associated with Pb toxicity and volatility as well as the variation in energy storage vs. temperature of PZT based devices. During the last six months of FY09 this work focused on developing syntheses for BTO nanoparticles and firing profiles for sintering BTO/glass composite capacitors.

Experimental verification of on-chip CMOS fractional-order capacitor emulators

KAUST Repository

Tsirimokou, G.

2016-06-13

The experimental results from a fabricated integrated circuit of fractional-order capacitor emulators are reported. The chip contains emulators of capacitors of orders 0.3, 0.4, 0.5, 0.6 and 0.7 with nano-Farad pseudo-capacitances that can be adjusted through a bias current. Two off-chip capacitors are used to set the bandwidth of each emulator independently. The chip was designed in Austria microsystems (AMS) 0.35μ CMOS. © 2016 The Institution of Engineering and Technology.

Experimental verification of on-chip CMOS fractional-order capacitor emulators

KAUST Repository

Tsirimokou, G.; Psychalinos, C.; Salama, Khaled N.; Elwakil, A.S.

2016-01-01

The experimental results from a fabricated integrated circuit of fractional-order capacitor emulators are reported. The chip contains emulators of capacitors of orders 0.3, 0.4, 0.5, 0.6 and 0.7 with nano-Farad pseudo-capacitances that can be adjusted through a bias current. Two off-chip capacitors are used to set the bandwidth of each emulator independently. The chip was designed in Austria microsystems (AMS) 0.35μ CMOS. © 2016 The Institution of Engineering and Technology.

A measurement technique of time-dependent dielectric breakdown in MOS capacitors

Science.gov (United States)

Li, S. P.

1974-01-01

The statistical nature of time-dependent dielectric breakdown characteristics in MOS capacitors was evidenced by testing large numbers of capacitors fabricated on single wafers. A multipoint probe and automatic electronic visual display technique are introduced that will yield statistical results which are necessary for the investigation of temperature, electric field, thermal annealing, and radiation effects in the breakdown characteristics, and an interpretation of the physical mechanisms involved. It is shown that capacitors of area greater than 0.002 sq cm may yield worst-case results, and that a multipoint probe of capacitors of smaller sizes can be used to obtain a profile of nonuniformities in the SiO2 films.

Capacitor discharge process for welding braided cable

Science.gov (United States)

Wilson, Rick D.

1995-01-01

A capacitor discharge process for welding a braided cable formed from a plurality of individual cable strands to a solid metallic electrically conductive member comprises the steps of: (a) preparing the electrically conductive member for welding by bevelling one of its end portions while leaving an ignition projection extending outwardly from the apex of the bevel; (b) clamping the electrically conductive member in a cathode fixture; (c) connecting the electrically conductive member clamped in the cathode fixture to a capacitor bank capable of being charged to a preselected voltage value; (d) preparing the braided cable for welding by wrapping one of its end portions with a metallic sheet to form a retaining ring operable to maintain the individual strands of the braided cable in fixed position within the retaining ring; (e) clamping the braided cable and the retaining ring as a unit in an anode fixture so that the wrapped end portion of the braided cable faces the ignition projection of the electrically conductive member; and (f) moving the cathode fixture towards the anode fixture until the ignition projection of the electrically conductive member contacts the end portion of the braided cable thereby allowing the capacitor bank to discharge through the electrically conductive member and through the braided cable and causing the electrically conductive member to be welded to the braided cable via capacitor discharge action.

Graphene electric double layer capacitor with ultra-high-power performance

International Nuclear Information System (INIS)

Miller, John R.; Outlaw, R.A.; Holloway, B.C.

2011-01-01

We have demonstrated, for the first time, efficient 120 Hz filtering by an electric double layer capacitor (EDLC). The key to this ultra-high-power performance is electrodes made from vertically oriented graphene nanosheets grown directly on metal current collectors. This design minimized both electronic and ionic resistance and produced capacitors having RC time-constants of less than 200 μs. Significantly, graphene nanosheets have a preponderance of exposed edge planes that greatly increase stored charge over designs relying on basal plane surfaces. Collectively these factors make vertically oriented graphene nanosheet electrodes ideally suited for producing high-frequency EDLCs. Capacitors constructed with these electrodes are predicted to be significantly smaller than aluminum electrolyte capacitors that they could functionally replace plus be manufactured using standard semiconductor process equipment, creating interesting commercial opportunities.

Multi-step capacitor discharges as an RF generator

International Nuclear Information System (INIS)

Hotta, Eiki; Yamamoto, Shunji; Ishii, Shozo; Hayashi, Izumi

1979-01-01

A variety of methods have been developed for large output radio frequency (RF) generators to heat and stabilize high temperature plasma. As the generators for this purpose, capacitor discharge, cable discharge, and oscillation with electronic tubes are considered. Here, a new RF generator is reported, which utilizes capacitor discharge to extract heavy current, and solves the difficulty of short duration by employing multistep discharges. The authors solved the problem of frequency decrease in capacitor discharge by cutting off the unnecessary capacitors reasonably from the load circuit, using the additional circuit for shunting current and vacuum gap switches. The vacuum gap switches and the trigger system are described together with the RF generator manufactured. The generator was fabricated to be rather compact for its large output and simple in circuitry as compared with conventional oscillator systems. The shortcomings are frequency variation and the improper phase of switching the next step in to cause instability, when the load change occurs. It would be difficult to operate the generator in a RF range of more than about 10 MHz due to jitter of the vacuum gap switches and others. (Wakatsuki, Y.)

All-printed capacitors with continuous solution dispensing technology

Science.gov (United States)

Ge, Yang; Plötner, Matthias; Berndt, Andreas; Kumar, Amit; Voit, Brigitte; Pospiech, Doris; Fischer, Wolf-Joachim

2017-09-01

Printed electronics have been introduced into the commercial markets in recent years. Various printing technologies have emerged aiming to process printed electronic devices with low cost, environmental friendliness, and compatibility with large areas and flexible substrates. The aim of this study is to propose a continuous solution dispensing technology for processing all-printed thin-film capacitors on glass substrates using a leading-edge printing instrument. Among all printing technologies, this study provides concrete proof of the following outstanding advantages of this technology: high tolerance to inks, high throughput, low cost, and precise pattern transfers. Ag nanoparticle ink based on glycol ethers was used to print the electrodes. To obtain dielectric ink, a copolymer powder of poly(methyl methacrylate-co-benzoylphenyl methacrylate) containing crosslinkable side groups was dissolved in anisole. Various layouts were designed to support multiple electronic applications. Scanning electron microscopy and atomic force microscopy were used to investigate the all-printed capacitor layers formed using the proposed process. Additionally, the printed capacitors were electrically characterized under direct current and alternating current. The measured electrical properties of the printed capacitors were consistent with the theoretical results.

The design and implementation of on-line monitoring system for UHV compact shunt capacitors

Science.gov (United States)

Tao, Weiliang; Ni, Xuefeng; Lin, Hao; Jiang, Shengbao

2017-08-01

Because of the large capacity and compact structure of the UHV compact shunt capacitor, it is difficult to take effective measures to detect and prevent the faults. If the fault capacitor fails to take timely maintenance, it will pose a threat to the safe operation of the system and the life safety of the maintenance personnel. The development of UHV compact shunt capacitor on-line monitoring system can detect and record the on-line operation information of UHV compact shunt capacitors, analyze and evaluate the early fault warning signs, find out the fault capacitor or the capacitor with fault symptom, to ensure safe and reliable operation of the system.

Graphene spin capacitor for magnetic field sensing

OpenAIRE

Semenov, Y. G.; Zavada, J. M.; Kim, K. W.

2010-01-01

An analysis of a novel magnetic field sensor based on a graphene spin capacitor is presented. The proposed device consists of graphene nanoribbons on top of an insulator material connected to a ferromagnetic source/drain. The time evolution of spin polarized electrons injected into the capacitor can be used for an accurate determination at room temperature of external magnetic fields. Assuming a spin relaxation time of 100 ns, magnetic fields on the order of $\\sim 10$ mOe may be detected at r...

Comb-Line Filter with Coupling Capacitor in Ground Plane

Directory of Open Access Journals (Sweden)

Toshiaki Kitamura

2011-01-01

Full Text Available A comb-line filter with a coupling capacitor in the ground plane is proposed. The filter consists of two quarter-wavelength microstrip resonators. A coupling capacitor is inserted into the ground plane in order to build strong coupling locally along the resonators. The filtering characteristics are investigated through numerical simulations as well as experiments. Filtering characteristics that have attenuation poles at both sides of the passband are obtained. The input susceptances of even and odd modes and coupling coefficients are discussed. The filters using stepped impedance resonators (SIRs are also discussed, and the effects of the coupling capacitor for an SIR structure are shown.

Device for detecting imminent failure of high-dielectric stress capacitors. [Patent application

Science.gov (United States)

McDuff, G.G.

1980-11-05

A device is described for detecting imminent failure of a high-dielectric stress capacitor utilizing circuitry for detecting pulse width variations and pulse magnitude variations. Inexpensive microprocessor circuitry is utilized to make numerical calculations of digital data supplied by detection circuitry for comparison of pulse width data and magnitude data to determine if preselected ranges have been exceeded, thereby indicating imminent failure of a capacitor. Detection circuitry may be incorporated in transmission lines, pulse power circuitry, including laser pulse circuitry or any circuitry where capacitors or capacitor banks are utilized.

Thyristor-controlled reactor improves series capacitor applications

Energy Technology Data Exchange (ETDEWEB)

Renz, K.W.; Thumm, G.; Weiss, S. [Siemens AG, Erlangen (Germany)

1995-12-31

Environmental considerations make it more and more difficult to plan and erect new transmission lines. FACTS (Flexible AC Transmission Systems) technology can provide devices to improve the utility of AC transmission lines. The innovative combination of conventional fixed series capacitors and thyristor controlled reactors as a new FACTS device was introduced into a transmission system in 1992. This Advanced Series Compensation (ASC) system provides many advantages not available with conventional fixed series capacitor installations such as flexible direct and continuous control of the compensation level, direct and smooth power flow control and improved capacitor bank protection. This new technology offers enhanced system flexibility by control of transmission line overload conditions, reduction in fault currents, sub-synchronous resonance (SSR) mitigation and network power oscillation damping. The world-first three-phase installation at Kayenta Substation, USA, demonstrates that modern FACTS devices using SVC thyristor valve technology can be designed and operated successfully. 6 refs, 7 figs

Nanostructured Anodic Multilayer Dielectric Stacked Metal-Insulator-Metal Capacitors.

Science.gov (United States)

Karthik, R; Kannadassan, D; Baghini, Maryam Shojaei; Mallick, P S

2015-12-01

This paper presents the fabrication of Al2O3/TiO2/Al2O3 metal-insulator-metal (MIM) capacitor using anodization technique. High capacitance density of > 3.5 fF/μm2, low quadratic voltage coefficient of capacitance of dielectric stack required for high performance MIM capacitor.

A high-performance trench capacitor integrated in a passive integration technology

International Nuclear Information System (INIS)

Geiselbrechtinger, Angelika; Büyüktas, Kevni; Allers, Karl-Heinz; Hartung, Wolfgang

2009-01-01

The requirements for the electrical characteristics of passive on-chip devices become more and more important. The electrical performance of RF circuits is predominantly restricted by the passives. New technologies and new device concepts are necessary to meet the demands. In this work, a trench capacitor developed for RF applications is presented for the first time. This so-called SilCap (silicon capacitor) device features very high capacitance density, extreme low-voltage dependence, excellent temperature stability, good RF performance and a high breakthrough voltage. First, the device function and the technological concept are introduced. The concept is realized without implementing cost-intensive high-k materials. This trench capacitor is integrated in the front end of line of a passive integration technology. The achieved specific capacitance density is compared to a standard planar capacitor. Performance of the SilCap in terms of quality factor and breakthrough voltage is shown. Finally, reliability data of this trench capacitor are presented with special focus on extrinsic and dielectric lifetime

Capacitor-based detection of nuclear magnetization: nuclear quadrupole resonance of surfaces.

Science.gov (United States)

Gregorovič, Alan; Apih, Tomaž; Kvasić, Ivan; Lužnik, Janko; Pirnat, Janez; Trontelj, Zvonko; Strle, Drago; Muševič, Igor

2011-03-01

We demonstrate excitation and detection of nuclear magnetization in a nuclear quadrupole resonance (NQR) experiment with a parallel plate capacitor, where the sample is located between the two capacitor plates and not in a coil as usually. While the sensitivity of this capacitor-based detection is found lower compared to an optimal coil-based detection of the same amount of sample, it becomes comparable in the case of very thin samples and even advantageous in the proximity of conducting bodies. This capacitor-based setup may find its application in acquisition of NQR signals from the surface layers on conducting bodies or in a portable tightly integrated nuclear magnetic resonance sensor. Copyright © 2010 Elsevier Inc. All rights reserved.

Prognostics Health Management and Physics based failure Models for Electrolytic Capacitors

Data.gov (United States)

National Aeronautics and Space Administration — This paper proposes first principles based modeling and prognostics approach for electrolytic capacitors. Electrolytic capacitors and MOSFETs are the two major...

Powering microbial electrolysis cells by capacitor circuits charged using microbial fuel cell

KAUST Repository

Hatzell, Marta C.

2013-05-01

A microbial electrolysis cell (MEC) was powered by a capacitor based energy storage circuit using energy from a microbial fuel cell (MFC) to increase MEC hydrogen production rates compared to that possible by the MFC alone. To prevent voltage reversal, MFCs charged the capacitors in a parallel configuration, and then the capacitors were discharged in series to boost the voltage that was used to power the MECs. The optimal capacitance for charging was found to be ∼0.01 F for each MFC. The use of the capacitor charging system increased energy recoveries from 9 to 13%, and hydrogen production rates increased from 0.31 to 0.72 m3 m-3-day-1, compared to coupled systems without capacitors. The circuit efficiency (the ratio of the energy that was discharged to the MEC to the energy provided to the capacitor from the MFCs) was ∼90%. These results provide an improved method for linking MFCs to MECs for renewable hydrogen gas production. © 2012 Elsevier B.V. All rights reserved.

Performance of ALVAND 1. capacitor bank

International Nuclear Information System (INIS)

Torabi-fard, A.; Farahani, M.; Ebrani, M.; Rostami, R.; Daghighian, F.

1978-01-01

This report describes the specifications of the capacitor bank for the ALVAND I, Linear theta pinch experiment and the results of some tests performed on it. A one-meter-wide module includes the basic components such as capacitors, Spark gaps, and crowbar triggers. Complementary parts such as ground system, pressurised dry air system and safety system were added. With a rise-time of about three micro-seconds and a total current of six million amperes it is possible to produce ion temperature in excess of one kev for a few microseconds. Different probes were used to measure the magnetic field and the total current

Switched-capacitor techniques for high-accuracy filter and ADC design

NARCIS (Netherlands)

Quinn, P.J.; Roermund, van A.H.M.

2007-01-01

Switched capacitor (SC) techniques are well proven to be excellent candidates for implementing critical analogue functions with high accuracy, surpassing other analogue techniques when embedded in mixed-signal CMOS VLSI. Conventional SC circuits are primarily limited in accuracy by a) capacitor

Integration substrate with a ultra-high-density capacitor and a through-substrate via

NARCIS (Netherlands)

Klootwijk, J.H.; Roozeboom, F.; Ruigrok, J.J.M.; Reefman, D.

2014-01-01

An integration substrate for a system in package comprises a through-substrate via and a trench capacitor wherein with a trench filling that includes at least four electrically conductive capacitor-electrode layers in an alternating arrangement with dielectric layers. --The capacitor-electrode

Lifetime Estimation of Electrolytic Capacitors in Fuel Cell Power Converter at Various Confidence Levels

DEFF Research Database (Denmark)

Zhou, Dao; Wang, Huai; Blaabjerg, Frede

2016-01-01

DC capacitors in power electronic converters are a major constraint on improvement of the power density and the reliability. In this paper, according to the degradation data of tested capacitors, the lifetime model of the component is analyzed at various confidence levels. Then, the mission profile...... based lifetime expectancy of the individual capacitor and the capacitor bank is estimated in a fuel cell backup power converter operating in both standby mode and operation mode. The lifetime prediction of the capacitor banks at different confidence levels is also obtained....

Capacitor Mismatch Error Cancellation Technique for a Successive Approximation A/D Converter

DEFF Research Database (Denmark)

Zheng, Zhiliang; Moon, Un-Ku; Steensgaard-Madsen, Jesper

1999-01-01

An error cancellation technique is described for suppressing capacitor mismatch in a successive approximation A/D converter. At the cost of a 50% increase in conversion time, the first-order capacitor mismatch error is cancelled. Methods for achieving top-plate parasitic insensitive operation...... are described, and the use of a gain- and offset-compensated opamp is explained. SWITCAP simulation results show that the proposed 16-bit SAR ADC can achieve an SNDR of over 91 dB under non-ideal conditions, including 1% 3 sigma nominal capacitor mismatch, 10-20% randomized parasitic capacitors, 66 dB opamp...

Low-dimensional carbon and MXene-based electrochemical capacitor electrodes.

Science.gov (United States)

Yoon, Yeoheung; Lee, Keunsik; Lee, Hyoyoung

2016-04-29

Due to their unique structure and outstanding intrinsic physical properties such as extraordinarily high electrical conductivity, large surface area, and various chemical functionalities, low-dimension-based materials exhibit great potential for application in electrochemical capacitors (ECs). The electrical properties of electrochemical capacitors are determined by the electrode materials. Because energy charge storage is a surface process, the surface properties of the electrode materials greatly influence the electrochemical performance of the cell. Recently, graphene, a single layer of sp(2)-bonded carbon atoms arrayed into two-dimensional carbon nanomaterial, has attracted wide interest as an electrode material for electrochemical capacitor applications due to its unique properties, including a high electrical conductivity and large surface area. Several low-dimensional materials with large surface areas and high conductivity such as onion-like carbons (OLCs), carbide-derived carbons (CDCs), carbon nanotubes (CNTs), graphene, metal hydroxide, transition metal dichalcogenides (TMDs), and most recently MXene, have been developed for electrochemical capacitors. Therefore, it is useful to understand the current issues of low-dimensional materials and their device applications.

Low-dimensional carbon and MXene-based electrochemical capacitor electrodes

International Nuclear Information System (INIS)

Yoon, Yeoheung; Lee, Hyoyoung; Lee, Keunsik

2016-01-01

Due to their unique structure and outstanding intrinsic physical properties such as extraordinarily high electrical conductivity, large surface area, and various chemical functionalities, low-dimension-based materials exhibit great potential for application in electrochemical capacitors (ECs). The electrical properties of electrochemical capacitors are determined by the electrode materials. Because energy charge storage is a surface process, the surface properties of the electrode materials greatly influence the electrochemical performance of the cell. Recently, graphene, a single layer of sp 2 -bonded carbon atoms arrayed into two-dimensional carbon nanomaterial, has attracted wide interest as an electrode material for electrochemical capacitor applications due to its unique properties, including a high electrical conductivity and large surface area. Several low-dimensional materials with large surface areas and high conductivity such as onion-like carbons (OLCs), carbide-derived carbons (CDCs), carbon nanotubes (CNTs), graphene, metal hydroxide, transition metal dichalcogenides (TMDs), and most recently MXene, have been developed for electrochemical capacitors. Therefore, it is useful to understand the current issues of low-dimensional materials and their device applications. (topical review)

Degradation testing and failure analysis of DC film capacitors under high humidity conditions

DEFF Research Database (Denmark)

Wang, Huai; Nielsen, Dennis Achton; Blaabjerg, Frede

2015-01-01

Metallized polypropylene film capacitors are widely used for high-voltage DC-link applications in power electronic converters. They generally have better reliability performance compared to aluminum electrolytic capacitors under electro-thermal stresses within specifications. However......, the degradation of the film capacitors is a concern in applications exposed to high humidity environments. This paper investigates the degradation of a type of plastic-boxed metallized DC film capacitors under different humidity conditions based on a total of 8700 h of accelerated testing and also post failure...... of interest is also presented. The study enables a better understanding of the humidity-related failure mechanisms and reliability performance of DC film capacitors for power electronics applications....

High Voltage Homemade Capacitor Charger for Plasma Focus System

International Nuclear Information System (INIS)

Abdul Halim Baijan; Azaman Ahmad; Rokiah Mohd Sabri; Siti Aiasah Hashim; Mohd Rizal Md Chulan; Wah, L.K.; Azhar Ahmad; Rosli Che Ros; Mohd Faiz Mohd Zin

2015-01-01

A high voltage capacitor charger has been designed and built to replace a high voltage charger type General Atomics CCDs Power Supply which was damaged. The fabrication design was using materials which were easily available in the local market. Among the main components of the high-voltage charger is a transformer for neon lights, variable transformer rated 0 - 240 V 1 KVA, and 240 V transformer isolator. The results of experiments that have been conducted shows that a homemade capacitor charger was able to charge high voltage capacitors up to the required voltage of which was 12 kV. However the time taken for charging is quite long, up to more than 6 minutes. (author)

Integration substrate with a ultra-high-density capacitor and a through-substrate via

NARCIS (Netherlands)

2008-01-01

An integration substrate for a system in package comprises a through-substrate via and a trench capacitor wherein with a trench filling that includes at least 4 elec. conductive capacitor-electrode layers in an alternating arrangement with dielec. layers. The capacitor-electrode layers are

CAPMIX -Deploying Capacitors for Salt Gradient Power Extraction

OpenAIRE

Bijmans, M.F.M.; Burheim, O.S.; Bryjak, M.; Delgado, A.; Hack, P.; Mantegazza, F.; Tenisson, S.; Hamelers, H.V.M.

2012-01-01

The process of mixing sea and river water can be utilised as a power source. At present, three groups of technology are established for doing so; i) mechanical; Pressure Retarded Osmosis PRO, ii) electrochemical reactions; Reverse ElectroDialysis (RED) and Nano Battery Electrodes (NBE) and iii) ultra capacitors; Capacitive Double Layer Expansion (CDLE) and Capacitors charge by the Donnan Potentials (CDP). The chemical potential for salt gradient power systems is only limited by th...

Force on an Asymmetric Capacitor

National Research Council Canada - National Science Library

Bahder, Thomas

2003-01-01

.... At present, the physical basis for the Biefeld-Brown effect is not understood. The order of magnitude of the net force on the asymmetric capacitor is estimated assuming two different mechanisms of charge conduction between its electrodes...

Capacitor current feedback for output filter damping in switched-mode magnet power supplies

International Nuclear Information System (INIS)

Paven Kumar, M.R.; Kim, J.M.S.

1994-01-01

In magnet power supplies for a particle accelerator system, a second-order low-pass filter is used to reduce the output current ripple content within specifications. The output filter must be properly damped in order to avoid any large amplification at the resonant frequency and large transient responses of voltages and currents at the step change of the line voltage. Conventionally, a series combination of resistance and capacitance is added in parallel with the filter capacitor to provide the required damping. This approach, however, requires a large dc-blocking capacitor which has to be several times larger than the filter capacitor. In this paper, a filter damping technique using capacitor current feedback is presented. The basic concept of the capacitor current feedback is established using a linear model of the converter involved, and then a sampled-data model of the converter is used to analyze the filter damping technique. The filter damping effect of the capacitor current feedback is verified experimentally

A frequency output ferroelectric phase PNZT capacitor-based temperature sensor

KAUST Repository

Khan, Naveed; Omran, Hesham; Yao, Yingbang; Salama, Khaled N.; Arsalan, Muhammad

2016-01-01

measured below the Curie temperature of the ferroelectric capacitor. The capacitance of the 20/80 (Zr/Ti) composition PNZT capacitor changes by 29% for a temperature change from 10°C to 100°C, which translates to 0.32%/°C temperature sensitivity

Flexible and weaveable capacitor wire based on a carbon nanocomposite fiber.

Science.gov (United States)

Ren, Jing; Bai, Wenyu; Guan, Guozhen; Zhang, Ye; Peng, Huisheng

2013-11-06

A flexible and weaveable electric double-layer capacitor wire is developed by twisting two aligned carbon nanotube/ordered mesoporous carbon composite fibers with remarkable mechanical and electronic properties as electrodes. This capacitor wire exhibits high specific capacitance and long life stability. Compared with the conventional planar structure, the capacitor wire is also lightweight and can be integrated into various textile structures that are particularly promising for portable and wearable electronic devices. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High voltage capacitor design and the determination of solid dielectric voltage breakdown

International Nuclear Information System (INIS)

Hutapea, S.

1976-01-01

The value of the external field intensity serves as an electrical insulating material and is a physical characteristic of the substance. Capacitor discharge in the dielectric medium are experimentally investigated. The high voltage power supply and other instrument needed are briefly discussed. Capacitors with working voltage of 30.000 volt and the plastic being used for dielectrics in the capacitors are also discussed. (author)

Metallized Film Capacitor Lifetime Evaluation and Failure Mode Analysis

CERN Document Server

Gallay, R.

2015-06-15

One of the main concerns for power electronic engineers regarding capacitors is to predict their remaining lifetime in order to anticipate costly failures or system unavailability. This may be achieved using a Weibull statistical law combined with acceleration factors for the temperature, the voltage, and the humidity. This paper discusses the different capacitor failure modes and their effects and consequences.

Enhancement of dielectric breakdown strengths in polymer film capacitors

International Nuclear Information System (INIS)

Binder, M.; Mammone, R.J.; Lavene, B.; Rondeau, E.

1992-01-01

This paper reports that breakdown voltages of wound, polymer film/metal foil capacitors have been dramatically increased by briefly exposing them (after they had been spirally wound) to a low pressure, low temperature gas plasma. Exposure of wound, polycarbonate-based capacitors to a 96%CF 4 /4%O 2 gas plasma for 4 minutes, for example, produced a 200% increase in breakdown voltage

Helping students understand real capacitors: measuring efficiencies in a school laboratory

International Nuclear Information System (INIS)

Simeão Carvalho, Paulo; Sampaio e Sousa, Adriano

2008-01-01

A recent reform in the Portuguese secondary school curriculum reintroduced the study of capacitors. Thus we decided to implement some experimental activities on this subject with our undergraduate students in physics education courses. A recent announcement of a new kind of capacitor being developed by a team of scientists at Massachusetts Institute of Technology (MIT), which makes use of nanotechnologies, was a great motivation for the study of a topic that could easily be considered 'out of time'. Since this new kind of capacitor is being seen as the battery of the future, our focus was essentially on efficiency measurements, motivating students to obtain, respectively, the time constant and the energies stored and supplied during the charge and discharge processes, from experimental graphics representing the power as a function of time in real capacitors

Enhanced DC-Link Capacitor Voltage Balancing Control of DC–AC Multilevel Multileg Converters

DEFF Research Database (Denmark)

Busquets-Monge, Sergio; Maheshwari, Ram Krishan; Nicolas-Apruzzese, Joan

2015-01-01

This paper presents a capacitor voltage balancing control applicable to any multilevel dc–ac converter formed by a single set of series-connected capacitors implementing the dc link and semiconductor devices, such as the diode-clamped topology. The control is defined for any number of dc-link vol......This paper presents a capacitor voltage balancing control applicable to any multilevel dc–ac converter formed by a single set of series-connected capacitors implementing the dc link and semiconductor devices, such as the diode-clamped topology. The control is defined for any number of dc...

Digital Realization of Capacitor-Voltage Feedback Active Damping for LCL-Filtered Grid Converters

DEFF Research Database (Denmark)

Xin, Zhen; Wang, Xiongfei; Loh, Poh Chiang

2015-01-01

The capacitor voltage of an LCL-filter can also be used for active damping, if it is fed back for synchronization. By this way, an extra current sensor can be avoided. Compared with the existing active damping techniques designed with capacitor current feedback, the capacitor voltage feedback....... To overcome their drawbacks, a new derivative method is then proposed, based on the non-ideal generalized integrator. The performance of the proposed derivative has been found to match the ideal “s” function closely. Active damping based on capacitor voltage feedback can therefore be realized accurately...

Simple hardware implementation of voltage balancing in capacitor-clamped inverter

Czech Academy of Sciences Publication Activity Database

Kokeš, Petr; Semerád, Radko

2009-01-01

Roč. 54, č. 4 (2009), s. 325-341 ISSN 0001-7043 R&D Projects: GA MPO FT-TA4/077 Institutional research plan: CEZ:AV0Z20570509 Keywords : capacitor -clamped multilevel inverter * flying capacitor voltage balancing * pulse width modulation (PWM) Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

Development of novel segmented-plate linearly tunable MEMS capacitors

International Nuclear Information System (INIS)

Shavezipur, M; Khajepour, A; Hashemi, S M

2008-01-01

In this paper, novel MEMS capacitors with flexible moving electrodes and high linearity and tunability are presented. The moving plate is divided into small and rigid segments connected to one another by connecting beams at their end nodes. Under each node there is a rigid step which selectively limits the vertical displacement of the node. A lumped model is developed to analytically solve the governing equations of coupled structural-electrostatic physics with mechanical contact. Using the analytical solver, an optimization program finds the best set of step heights that provides the highest linearity. Analytical and finite element analyses of two capacitors with three-segmented- and six-segmented-plate confirm that the segmentation technique considerably improves the linearity while the tunability remains as high as that of a conventional parallel-plate capacitor. Moreover, since the new designs require customized fabrication processes, to demonstrate the applicability of the proposed technique for standard processes, a modified capacitor with flexible steps designed for PolyMUMPs is introduced. Dimensional optimization of the modified design results in a combination of high linearity and tunability. Constraining the displacement of the moving plate can be extended to more complex geometries to obtain smooth and highly linear responses

Printed Barium Strontium Titanate capacitors on silicon

Energy Technology Data Exchange (ETDEWEB)

Sette, Daniele [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Luxembourg Institute of Science and Technology LIST, Materials Research and Technology Department, L-4422 Belvaux (Luxembourg); Kovacova, Veronika [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Defay, Emmanuel, E-mail: emmanuel.defay@list.lu [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Luxembourg Institute of Science and Technology LIST, Materials Research and Technology Department, L-4422 Belvaux (Luxembourg)

2015-08-31

In this paper, we show that Barium Strontium Titanate (BST) films can be prepared by inkjet printing of sol–gel precursors on platinized silicon substrate. Moreover, a functional variable capacitor working in the GHz range has been made without any lithography or etching steps. Finally, this technology requires 40 times less precursors than the standard sol–gel spin-coating technique. - Highlights: • Inkjet printing of Barium Strontium Titanate films • Deposition on silicon substrate • Inkjet printed silver top electrode • First ever BST films thinner than 1 μm RF functional variable capacitor that has required no lithography.

Investigation on Capacitor Switching Transient Limiter with a Three phase Variable Resistance

DEFF Research Database (Denmark)

Naderi, Seyed Behzad; Jafari, Mehdi; Zandnia, Amir

2017-01-01

In this paper, a capacitor switching transient limiter based on a three phase variable resistance is proposed. The proposed structure eliminates the capacitor switching transient current and over-voltage by introducing a variable resistance to the current path with its special switching pattern...... transients on capacitor after bypassing. Analytic Analyses for this structure in transient cases are presented in details and simulations are performed by MATLAB software to prove its effectiveness....

Carbons, ionic liquids and quinones for electrochemical capacitors

Directory of Open Access Journals (Sweden)

Raul eDiaz

2016-04-01

Full Text Available Carbons are the main electrode materials used in electrochemical capacitors, which are electrochemical energy storage devices with high power densities and long cycling lifetimes. However, increasing their energy density will improve their potential for commercial implementation. In this regard, the use of high surface area carbons and high voltage electrolytes are well known strategies to increase the attainable energy density, and lately ionic liquids have been explored as promising alternatives to current state of the art acetonitrile-based electrolytes. Also, in terms of safety and sustainability ionic liquids are attractive electrolyte materials for electrochemical capacitors. In addition, it has been shown that the matching of the carbon pore size with the electrolyte ion size further increases the attainable electric double layer (EDL capacitance and energy density.The use of pseudocapacitive reactions can significantly increase the attainable energy density, and quinonic-based materials offer a potentially sustainable and cost effective research avenue for both the electrode and the electrolyte. This perspective will provide an overview of the current state of the art research on electrochemical capacitors based on combinations of carbons, ionic liquids and quinonic compounds, highlighting performances and challenges and discussing possible future research avenues. In this regard, current interest is mainly focused on strategies which may ultimately lead to commercially competitive sustainable high performance electrochemical capacitors for different applications including those requiring mechanical flexibility and biocompatibility.

High Energy Density Capacitors, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Capacitor size and reliability are often limiting factors in pulse power, high speed switching, and power management and distribution (PMAD) systems. T/J...

Microstrip Resonator for High Field MRI with Capacitor-Segmented Strip and Ground Plane

DEFF Research Database (Denmark)

Zhurbenko, Vitaliy; Boer, Vincent; Petersen, Esben Thade

2017-01-01

) segmenting stripe and ground plane of the resonator with series capacitors. The design equations for capacitors providing symmetric current distribution are derived. The performance of two types of segmented resonators are investigated experimentally. To authors’ knowledge, a microstrip resonator, where both......, strip and ground plane are capacitor-segmented, is shown here for the first time....

Graphene/VO2 hybrid material for high performance electrochemical capacitor

International Nuclear Information System (INIS)

Deng, Lingjuan; Zhang, Gaini; Kang, Liping; Lei, Zhibin; Liu, Chunling; Liu, Zong-Huai

2013-01-01

Graphical abstract: Graphene/VO 2 hybrid materials are prepared by one-step simultaneous hydrothermal reduction technology. The prepared graphene (1.0)/VO 2 hybrid material shows a specific capacitances of 225 F g −1 in 0.5 mol L −1 K 2 SO 4 solution. Furthermore, an asymmetric electrochemical capacitor with graphene (1.0)/VO 2 as a positive electrode and graphene as a negative electrode is assembled, and it can work in a cell voltage of 1.7 V and show excellent capacitive property. - Highlights: • Graphene/VO 2 hybrid material has been prepared by one-step hydrothermal reduction. • Graphene/VO 2 hybrid material exhibits high specific capacitance. • An asymmetric capacitor working at 1.7 V in aqueous solution is assembled based on graphene/VO 2 electrode. • The asymmetric capacitor exhibits high energy density. - Abstract: Vanadium oxides have attracted significant attention for electrochemical capacitor because of their extensive multifunctional properties. In the present work, graphene/VO 2 (RG/VO 2 ) hybrid materials with different RG amounts are prepared in a mixture of ammonium vanadate, formic acid and graphite oxide (GO) nanosheets by one-step simultaneous hydrothermal reduction technology. The hydrothermal treatment makes the reduction of GO into RG and the formation of VO 2 particles with starfruit morphology. The starfruit-like VO 2 particles are uniformly embedded in the hole constructed by RG nanosheets, which makes the electrode–electrolyte contact better. A high specific capacitance of 225 F g −1 has been achieved for RG(1.0)/VO 2 electrode with RG content of 26 wt% in 0.5 mol L −1 K 2 SO 4 electrolyte. An asymmetrical electrochemical capacitor is assembled by using RG(1.0)/VO 2 as positive electrode and RG as negative electrode, and it can be reversibly charged–discharged at a cell voltage of 1.7 V in 0.5 mol L −1 K 2 SO 4 electrolyte. The asymmetrical capacitor can deliver an energy density of 22.8 Wh kg −1 at a power density

Electrochemical properties of arc-black and carbon nano-balloon as electrochemical capacitor electrodes

International Nuclear Information System (INIS)

Sato, T; Suda, Y; Uruno, H; Takikawa, H; Tanoue, H; Ue, H; Aoyagi, N; Okawa, T; Shimizu, K

2012-01-01

In this study, we used two types of carbon nanomaterials, arc-black (AcB) which has an amorphous structure and carbon nano-balloon (CNB) which has a graphitic structure as electrochemical capacitor electrodes. We made a coin electrode from these carbon materials and fabricated an electric double-layer capacitor (EDLC) that sandwiches a separator between the coin electrodes. On the other hand, RuO 2 was loaded on these carbon materials, and we fabricated a pseudo-capacitor that has an ion insertion mechanism into RuO 2 . For comparison with these carbon materials, activated carbon (AC) was also used for a capacitor electrode. The electrochemical properties of all the capacitors were evaluated in 1M H 2 SO 4 aqueous solution. As a result of EDLC performance, AcB electrode had a higher specific capacitance than AC electrode at a high scan rate (≥ 100 mV/s). In the evaluation of pseudo-capacitor performance, RuO 2 -loaded CNB electrode showed a high specific capacitance of 734 F/g per RuO 2 weight.

Algebraic techniques for diagonalization of a split quaternion matrix in split quaternionic mechanics

International Nuclear Information System (INIS)

Jiang, Tongsong; Jiang, Ziwu; Zhang, Zhaozhong

2015-01-01

In the study of the relation between complexified classical and non-Hermitian quantum mechanics, physicists found that there are links to quaternionic and split quaternionic mechanics, and this leads to the possibility of employing algebraic techniques of split quaternions to tackle some problems in complexified classical and quantum mechanics. This paper, by means of real representation of a split quaternion matrix, studies the problem of diagonalization of a split quaternion matrix and gives algebraic techniques for diagonalization of split quaternion matrices in split quaternionic mechanics

A new method of optimal capacitor switching based on minimum spanning tree theory in distribution systems

Science.gov (United States)

Li, H. W.; Pan, Z. Y.; Ren, Y. B.; Wang, J.; Gan, Y. L.; Zheng, Z. Z.; Wang, W.

2018-03-01

According to the radial operation characteristics in distribution systems, this paper proposes a new method based on minimum spanning trees method for optimal capacitor switching. Firstly, taking the minimal active power loss as objective function and not considering the capacity constraints of capacitors and source, this paper uses Prim algorithm among minimum spanning trees algorithms to get the power supply ranges of capacitors and source. Then with the capacity constraints of capacitors considered, capacitors are ranked by the method of breadth-first search. In term of the order from high to low of capacitor ranking, capacitor compensation capacity based on their power supply range is calculated. Finally, IEEE 69 bus system is adopted to test the accuracy and practicality of the proposed algorithm.

The effect of a chlorhexidine-fluoride varnish on mutans streptococci counts and laser fluorescence readings in occlusal fissures of permanent teeth

DEFF Research Database (Denmark)

Lipták, Lídia; Bársony, Nóra; Twetman, Svante

2016-01-01

Objective: To evaluate the effect of a new chlorhexidinefluor ide varnish on mutans streptococci (MS) counts and laser fluorescence (LF) readings in fissures of permanent molars. Method and Materials: The study group consisted of 57 healthy schoolchildren (7 to 14 yrs) that volunteered after...... informed consent. A double-blind split-mouth design was employed and 87 pairs of non-cavitated permanent molars were randomly assigned to treatments with either chlorhexidine- fluoride varnish (CHX-F) or chlorhexidine-thymol varnish (CHX-T, Cervitec Plus) as active control. The varnishes were topically...

Simulation and Analysis of Magnetisation Characteristics of Interior Permanent Magnet Motors

Directory of Open Access Journals (Sweden)

J. A. Walker

2005-01-01

Full Text Available Modern permanent magnet (PM synchronous brushless machines often have magnetic circuits in which the patterns of saturation are complex and highly variable with the position of the rotor. The classical phasor diagram theory of operation relies on the assumption of sinusoidal variation of flux-linkage with rotor position, and neglects the non-linear effects that arise in different operating states. The finite element method is a useful tool for detailed magnetic analysis, but it is important to verify simulation results by direct measurement of the magnetic characteristics of the motor, in terms of “magnetisation curves” of current and flux-linkage. This paper presents results from finite element simulations to determine the magnetisation in a split-phase interior permanent magnet (IPM motor. Investigation has been made to determine the effects of the rotor geometry on the synchronous reactances and airgap flux distribution. Comparisons are made with a second IPM motor with a different rotor configuration. 

Online MOS Capacitor Characterization in LabVIEW Environment

Directory of Open Access Journals (Sweden)

Chinmay K Maiti

2009-08-01

Full Text Available We present an automated evaluation procedure to characterize MOS capacitors involving high-k gate dielectrics. Suitability of LabVIEW environment for online web-based semiconductor device characterization is demonstrated. Developed algorithms have been successfully applied to automate the MOS capacitor measurements for Capacitance-Voltage, Conductance-Voltage and Current-Voltage characteristics. Implementation of the algorithm for use as a remote internet-based characterization tool where the client and server communicate with each other via web services is also shown.

Numerical investigation of phase change materials thermal capacitor for pipe flow

Directory of Open Access Journals (Sweden)

Kurnia Jundika Candra

2017-01-01

Full Text Available This study addresses the performance of phase change material as thermal capacitor. A computational fluid dynamics (CFD model is developed to take into account the conjugate heat transfer between water as the heat transfer fluid (HTF and PCM as thermal capacitor. A pulsating inlet temperature with constant inlet velocity is prescribed to represent temperature variation. The performance of thermal capacitor is evaluated by closely monitoring outlet temperature and comparing it with inlet temperature to examine the reduction in temperature fluctuation. To intensify heat transfer between HTF and PCM, extended surfaces (fins are installed on PCM side. The results indicate that PCM thermal capacitor can reduce temperature fluctuation by ∼ 1 °C. This reduction can be improved further when extended surface is installed with ∼ 1.5 °C reduction in temperature fluctuation is achieved. Moreover, it is found that the maximum temperature is delayed at the outlet due to slow conjugate heat transfer between HTF and PCM. Inlet velocity is found to have considerable influence of the temperature fluctuation reduction: Slower inlet velocity results in a better temperature fluctuation reduction. This study is expected to serve as a guideline in designing PCM-based thermal capacitor.

Influence of Mixed Solvent on the Electrochemical Property of Hybrid Capacitor.

Science.gov (United States)

Lee, Byunggwan; Yoon, J R

2015-11-01

The hybrid capacitors (2245 size, cylindrical type) were prepared by using activated carbon cathode and Li4Ti5O12 anode. In order to improve the cell operation at high temperature range, propylene carbonate (PC) was used in combination with acetonitrile (AN) with volume ratio of 7:3, 5:5, and 3:7, respectively. We investigated the electrochemical behavior of the hybrid capacitors that enabled cell operation with stability at high temperature. The organic electrolyte of hybrid capacitor containing PC and AN with a volume ratio 7:3 intended to exhibit highly reversible cycle performance with good capacity retention at 60 degrees C after 2200 cycles. From this study, it has been found that the very strong influence of the solvent nature on the characteristics of hybrid capacitor, and the difference in performance associated with the two solvents.

High Energy Density Polymer Film Capacitors

National Research Council Canada - National Science Library

Boufelfel, Ali

2006-01-01

High-energy-density capacitors that are compact and light-weight are extremely valuable in a number of critical DoD systems that include portable field equipment, pulsed lasers, detection equipment...

Mission Profile Translation to Capacitor Stresses in Grid-Connected Photovoltaic Systems

DEFF Research Database (Denmark)

Yang, Yongheng; Ma, Ke; Wang, Huai

2014-01-01

DC capacitors are widely adopted in grid-connected PhotoVoltaic(PV) systems for power stabilization and control decoupling. They have become one of the critical components in grid-connected PV inverters in terms of cost, reliability and volume. The electrical and thermal stresses of the DC...... stresses of the DC capacitors under both normal and abnormal grid conditions. As a consequence, this investigation provides new insights into the sizing and reliability prediction of those capacitors with respect to priorart studies. Two study cases on a single-stage PV inverter and a two-stage PV inverter...

Application of proton conducting polymeric electrolytes to electrochemical capacitors

International Nuclear Information System (INIS)

Morita, Masayuki; Qiao, Jin-Li; Yoshimoto, Nobuko; Ishikawa, Masashi

2004-01-01

Non-aqueous polymeric gel complexes composed of poly(ethylene oxide)-modified polymethacrylate (PEO-PMA) dissolving anhydrous H 3 PO 4 have been examined as solid electrolytes of electrochemical capacitors. High ionic conductivity of ∼10 -3 S cm -1 (at 70 deg. C) was obtained for non-aqueous gel systems based on PEO-PMA with proper amounts of organic plasticizers. The ionic conductivity depended on the composition of the gel, especially on the content of the dopant H 3 PO 4 . A test cell of the electric double layer capacitor (EDLC) was assembled using the present gel electrolyte with activated carbon fiber (ACF) cloth electrodes. It gave as high capacity as that obtained for the capacitor using an aqueous liquid electrolyte. High rate capability was obtained for the cell operating at 90 deg. C

PLZT capacitor and method to increase the dielectric constant

Science.gov (United States)

Taylor, Ralph S.; Fairchild, Manuel Ray; Balachjandran, Uthamalingam; Lee, Tae H.

2017-12-12

A ceramic-capacitor includes a first electrically-conductive-layer, a second electrically-conductive-layer arranged proximate to the first electrically-conductive-layer, and a dielectric-layer interposed between the first electrically-conductive-layer and the second electrically-conductive-layer. The dielectric-layer is formed of a lead-lanthanum-zirconium-titanate material (PLZT), wherein the PLZT is characterized by a dielectric-constant greater than 125, when measured at 25 degrees Celsius and zero Volts bias, and an excitation frequency of ten-thousand Hertz (10 kHz). A method for increasing a dielectric constant of the lead-lanthanum-zirconium-titanate material (PLZT) includes the steps of depositing PLZT to form a dielectric-layer of a ceramic-capacitor, and heating the ceramic-capacitor to a temperature not greater than 300.degree. C.

Current status of environmental, health, and safety issues of electrochemical capacitors for advanced vehicle applications

Energy Technology Data Exchange (ETDEWEB)

Vimmerstedt, L J; Hammel, C J

1997-04-01

Electrochemical capacitors are a candidate for traction power assists in hybrid electric vehicles (HEVs). Other advanced automotive applications, while not the primary focus of current development efforts, are also possible. These include load leveling high-energy batteries, power conditioning electronics, electrically hated catalysts, electric power steering, and engine starter power. Higher power and longer cycle life are expected for electrochemical capacitors than for batteries. Evaluation of environmental, health, and safety (EH and S) issues of electrochemical capacitors is an essential part of the development and commercialization of electrochemical capacitors for advanced vehicles. This report provides an initial EH and S assessment. This report presents electrochemical capacitor electrochemistry, materials selection, intrinsic material hazards, mitigation of those hazards, environmental requirements, pollution control options, and shipping requirements. Most of the information available for this assessment pertains to commercial devices intended for application outside the advanced vehicle market and to experiment or prototype devices. Electrochemical capacitors for power assists in HEVs are not produced commercially now. Therefore, materials for advanced vehicle electrochemical capacitors may change, and so would the corresponding EH and S issues. Although changes are possible, this report describes issues for likely electrochemical capacitor designs.

Improved Dielectric Films For Capacitors

Science.gov (United States)

Yen, Shiao-Ping S.; Lewis, Carol R.; Cygan, Peter J.; Jow, T. Richard

1994-01-01

Dielectric films made from blends of some commercially available high-dielectric-constant cyanoresins with each other and with cellulose triacetate (CTA) have both high dielectric constants and high breakdown strengths. Dielectric constants as high as 16.2. Films used to produce high-energy-density capacitors.

Condition Monitoring for DC-link Capacitors Based on Artificial Neural Network Algorithm

DEFF Research Database (Denmark)

Soliman, Hammam Abdelaal Hammam; Wang, Huai; Gadalla, Brwene Salah Abdelkarim

2015-01-01

hardware will reduce the cost, and therefore could be more promising for industry applications. A condition monitoring method based on Artificial Neural Network (ANN) algorithm is therefore proposed in this paper. The implementation of the ANN to the DC-link capacitor condition monitoring in a back......In power electronic systems, capacitor is one of the reliability critical components . Recently, the condition monitoring of capacitors to estimate their health status have been attracted by the academic research. Industry applications require more reliable power electronics products...... with preventive maintenance. However, the existing capacitor condition monitoring methods suffer from either increased hardware cost or low estimation accuracy, being the challenges to be adopted in industry applications. New development in condition monitoring technology with software solutions without extra...

A frequency output ferroelectric phase PNZT capacitor-based temperature sensor

KAUST Repository

Khan, Naveed

2016-09-05

In this paper, a frequency output temperature sensor based on a 4% Niobium doped 20/80 Zr/Ti Lead Zirconate Titanate (PNZT) capacitor is proposed. The sensor capacitance vs temperature and capacitance vs voltage characteristics are experimentally measured below the Curie temperature of the ferroelectric capacitor. The capacitance of the 20/80 (Zr/Ti) composition PNZT capacitor changes by 29% for a temperature change from 10°C to 100°C, which translates to 0.32%/°C temperature sensitivity. The measured sensor characteristics show less than ∼0.7°C deviation from the ideal linear response. A Wien bridge oscillator based temperature sensor is demonstrated based on the PNZT capacitors. Mathematical analysis for the effect of the op-amp finite unity-gain frequency on the sensor circuit oscillation frequency is provided. The experimentally realized frequency output temperature sensor shows -17.6% relative frequency change for a temperature change from 10°C to 100°C. The proposed capacitive temperature sensor can be used in low-power smart sensor nodes without the need for extensive calibration. © 2015 IEEE.

Gamma radiation in ceramic capacitors: a study for space missions

Science.gov (United States)

dos Santos Ferreira, Eduardo; Sarango Souza, Juliana

2017-10-01

We studied the real time effects of the gamma radiation in ceramic capacitors, in order to evaluate the effects of cosmic radiation on these devices. Space missions have electronic circuits with various types of devices, many studies have been done on semiconductor devices exposed to gamma radiation, but almost no studies for passive components, in particular ceramic capacitors. Commercially sold ceramic capacitors were exposed to gamma radiation, and the capacitance was measured before and after exposure. The results clearly show that the capacitance decreases with exposure to gamma radiation. We confirmed this observation in a real time capacitance measurement, obtained using a data logging system developed by us using the open source Arduino platform.

Polarization Insensitivity in Double-Split Ring and Triple-Split Ring Terahertz Resonators

International Nuclear Information System (INIS)

Wu Qian-Nan; Lan Feng; Tang Xiao-Pin; Yang Zi-Qiang

2015-01-01

A modified double-split ring resonator and a modified triple-split ring resonator, which offer polarization-insensitive performance, are investigated, designed and fabricated. By displacing the two gaps of the conventional double-split ring resonator away from the center, the second resonant frequency for the 0° polarized wave and the resonant frequency for the 90° polarized wave become increasingly close to each other until they are finally identical. Theoretical and experimental results show that the modified double-split ring resonator and the modified triple-split ring resonator are insensitive to different polarized waves and show strong resonant frequency dips near 433 and 444 GHz, respectively. The results of this work suggest new opportunities for the investigation and design of polarization-dependent terahertz devices based on split ring resonators. (paper)

Pre-charging of module capacitors of MMC when the module ...

Indian Academy of Sciences (India)

Shamkant D Joshi

The module capacitors need to be pre-charged, to power the control circuit. The problem faced while ... It consists of three legs to share a common DC link voltage. Each of these legs has ... Consider the stability of a system with only one capacitor with negative ..... number of wires because separate wires are not required for.

Ferroelectric Thin-Film Capacitors and Piezoelectric Switches for Mobile Communication Applications

NARCIS (Netherlands)

Klee, Mareike; van Esch, Harry; Keur, Wilco; Kumar, Biju; van Leuken-Peters, Linda; Liu, Jin; Mauczok, Rüdiger; Neumann, Kai; Reimann, Klaus; Renders, Christel; Roest, Aarnoud L.; Tiggelman, M.P.J.; de Wild, Marco; Wunnicke, Olaf; Zhao, Jing

2009-01-01

Thin-film ferroelectric capacitors have been integrated with resistors and active functions such as ESD protection into small, miniaturized modules, which enable a board space saving of up to 80%. With the optimum materials and processes, integrated capacitors with capacitance densities of up to 100

Nitrogen-Doped Holey Graphene Film-Based Ultrafast Electrochemical Capacitors.

Science.gov (United States)

Zhou, Qinqin; Zhang, Miao; Chen, Ji; Hong, Jong-Dal; Shi, Gaoquan

2016-08-17

The commercialized aluminum electrolytic capacitors (AECs) currently used for alternating current (AC) line-filtering are usually the largest components in the electronic circuits because of their low specific capacitances and bulky sizes. Herein, nitrogen-doped holey graphene (NHG) films were prepared by thermal annealing the composite films of polyvinylpyrrolidone (PVP), graphene oxide (GO), and ferric oxide (Fe2O3) nanorods followed by chemical etching with hydrochloride acid. The typical electrochemical capacitor with NHG electrodes exhibited high areal and volumetric specific capacitances of 478 μF cm(-2) and 1.2 F cm(-3) at 120 Hz, ultrafast frequency response with a phase angle of -81.2° and a resistor-capacitor time constant of 203 μs at 120 Hz, as well as excellent cycling stability. Thus, it is promising to replace conventional AEC for AC line-filtering in miniaturized electronics.

FEATURES OF SELECTION OF CAPACITOR BANKS IN ELECTRIC NETWORKS WITH INTERHARMONIC SOURCES

Directory of Open Access Journals (Sweden)

Yu. L. Sayenko

2017-10-01

Full Text Available Purpose. Development of a methodology for selecting capacitor bank parameters designed to compensate for reactive power, if there are sources of interharmonics in the electrical network. Development of a methodology for selecting the parameters of capacitor banks that are part of resonant filters of higher harmonics and interharmonics. Methodology. For the research, we used the decomposition of the non-sinusoidal voltage (current curve into the sum of the harmonic components with frequencies as multiple of the fundamental frequency - higher harmonics, and not multiple fundamental frequencies - interharmonics. Results. Expressions are obtained for checking the absence of inadmissible overloads of capacitor banks by voltage and current in the presence of voltage (current in the curve, along with higher harmonics, of the discrete spectrum of interharmonics. When selecting capacitor banks, both for reactive power compensation and for filter-compensating devices, the necessity of constructing the frequency characteristics of the input and mutual resistances of the electrical network for analyzing possible resonant phenomena is confirmed. Originality. The expediency of simplified calculation of the voltage variation at the terminals of the banks of the capacitors of the higher harmonics filters and interharmonics due to the presence of the reactor in the filters is substantiated. Practical value. The use of the proposed approaches will make it possible to resolve a number of issues related to the choice of parameters of capacitor banks in networks with nonlinear loads, including: ensuring reliable operation of capacitor banks when their parameters deviate from their nominal values, as well as deviations in the parameters of the supply network and sources of harmonic distortion; ensuring the absence of resonant phenomena at frequencies of both higher harmonics and interharmonics.

Bad splits in bilateral sagittal split osteotomy: systematic review of fracture patterns.

Science.gov (United States)

Steenen, S A; Becking, A G

2016-07-01

An unfavourable and unanticipated pattern of the mandibular sagittal split osteotomy is generally referred to as a 'bad split'. Few restorative techniques to manage the situation have been described. In this article, a classification of reported bad split pattern types is proposed and appropriate salvage procedures to manage the different types of undesired fracture are presented. A systematic review was undertaken, yielding a total of 33 studies published between 1971 and 2015. These reported a total of 458 cases of bad splits among 19,527 sagittal ramus osteotomies in 10,271 patients. The total reported incidence of bad split was 2.3% of sagittal splits. The most frequently encountered were buccal plate fractures of the proximal segment (types 1A-F) and lingual fractures of the distal segment (types 2A and 2B). Coronoid fractures (type 3) and condylar neck fractures (type 4) have seldom been reported. The various types of bad split may require different salvage approaches. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Difference in Thermal Degradation Behavior of ZrO2 and HfO2 Anodized Capacitors

Science.gov (United States)

Kamijyo, Masahiro; Onozuka, Tomotake; Yoshida, Naoto; Shinkai, Satoko; Sasaki, Katsutaka; Yamane, Misao; Abe, Yoshio

2004-09-01

Microcrystalline ZrO2 and HfO2 thin film capacitors were prepared by anodizing sputter-deposited Zr and Hf films. The thermal degradation behavior of both anodized capacitors was clarified by the measurement of their capacitance properties and Auger depth profiles before and after heat treatment in air. As a result, it is confirmed that the heat-resistance property of the HfO2 anodized capacitor is superior to that of the ZrO2 capacitor. In addition, it is revealed that the thermal degradation of the ZrO2 anodized capacitor is caused by the diffusion of Zr atoms from the underlying layer into the ZrO2 anodized layer, while that of the HfO2 anodized capacitor is caused by the diffusion of oxygen atoms from the anodized layer into the underlying Hf layer.

A Review of the Condition Monitoring of Capacitors in Power Electronic Converters

DEFF Research Database (Denmark)

Soliman, Hammam Abdelaal Hammam; Wang, Huai; Blaabjerg, Frede

2015-01-01

Capacitor is one of the reliability critical components in power electronic systems. In the last two decades, many efforts in the academic research have been devoted to the condition monitoring of capacitors to estimate their health status. Industry applications demand more reliable power...... electronics products with preventive maintenance. Nevertheless, most of the developed capacitor condition monitoring technologies are rarely adopted by industry due to the complexity, increased cost and other relevant issues. An overview of the prior-art research in this area is therefore needed to justify....... Therefore, this paper firstly classifies the capacitor condition monitoring methods into three categories, then the respective technology evolution from 1993 to 2015 is summarized. Remarks on the state-of-the-art research and the future opportunities targeting for practical industry applications are given....

A Review of the Condition Monitoring of Capacitors in Power Electronic Converters

DEFF Research Database (Denmark)

Soliman, Hammam Abdelaal Hammam; Wang, Huai; Blaabjerg, Frede

2016-01-01

Capacitors are one type of reliability-critical components in power electronic systems. In the last two decades, many efforts in academic research have been devoted to the condition monitoring of capacitors to estimate their health status. Industry applications are demanding more reliable power...... electronics products with preventive maintenance. Nevertheless, most of the developed capacitor condition monitoring technologies are rarely adopted by industry due to the complexity, increased cost, and other relevant issues. An overview of the prior-art research in this area is therefore needed to justify......, this paper first classifies the capacitor condition monitoring methods into three categories, then the respective technology evolution in the last two decades is summarized. Finally, the state-of-the-art research and the future opportunities targeting for industry applications are given....

Dental age estimation in Japanese individuals combining permanent teeth and third molars.

Science.gov (United States)

Ramanan, Namratha; Thevissen, Patrick; Fleuws, Steffen; Willems, G

2012-12-01

The study aim was, firstly, to verify the Willems et al. model on a Japanese reference sample. Secondly to develop a Japanese reference model based on the Willems et al. method and to verify it. Thirdly to analyze the age prediction performance adding tooth development information of third molars to permanent teeth. Retrospectively 1877 panoramic radiographs were selected in the age range between 1 and 23 years (1248 children, 629 sub-adults). Dental development was registered applying Demirjian 's stages of the mandibular left permanent teeth in children and Köhler stages on the third molars. The children's data were, firstly, used to validate the Willems et al. model (developed a Belgian reference sample), secondly, split ino a training and a test sample. On the training sample a Japanese reference model was developed based on the Willems method. The developed model and the Willems et al; model were verified on the test sample. Regression analysis was used to detect the age prediction performance adding third molar scores to permanent tooth scores. The validated Willems et al. model provided a mean absolute error of 0.85 and 0.75 years in females and males, respectively. The mean absolute error in the verified Willems et al. and the developed Japanese reference model was 0.85, 0.77 and 0.79, 0.75 years in females and males, respectively. On average a negligible change in root mean square error values was detected adding third molar scores to permanent teeth scores. The Belgian sample could be used as a reference model to estimate the age of the Japanese individuals. Combining information from the third molars and permanent teeth was not providing clinically significant improvement of age predictions based on permanent teeth information alone.

Capacitors and Resistance-Capacitance Networks.

Science.gov (United States)

Balabanian, Norman; Root, Augustin A.

This programed textbook was developed under a contract with the United States Office of Education as Number 5 in a series of materials for use in an electrical engineering sequence. It is divided into three parts--(1) capacitors, (2) voltage-current relationships, and (3) simple resistance-capacitance networks. (DH)

100 kV, 80 kJ low-induction capacitor module

International Nuclear Information System (INIS)

Andrezen, A.B.; Burtsev, V.A.; Vodovozov, V.M.; Drozdov, A.A.; Makeev, G.M.

1980-01-01

A low induction capacitor module has been developed to investigate THETA- and Z-pinch plasma. Energy output time of the module lays in the microsecond range. The 100 kV, 80 kJ module is based on low-induction castor capasitors. The module is equipped with two solid dielectric dischargers, the system of discharger ignition protection system and automatic system for charging of capacitors. The module discharge period T 0 =5.6 μs. The capacitor module has been used in investigations of electric explosions of Al plane foils in the pulverized quartz. The overvoltage Usub(max)/Usub(o) approximately equal to 10 has been received at the maximum intensity of the electric field Esub(max) approximately equal to 12 kV/sm [ru

Fatigue-free lead zirconate titanate-based capacitors for nonvolatile memories

International Nuclear Information System (INIS)

Shannigrahi, S. R.; Jang, Hyun M.

2001-01-01

The development of lead zirconate titanate (PZT)-based capacitors has been a long time goal of ferroelectric random access memories (FRAM). However, PZT-based perovskites with common platinum (Pt) electrodes have suffered from a significant reduction of the remanent polarization (P r ) after a certain number of read/write cycles (electrical fatigue). We now report the development of fatigue-free lanthanum-modified PZT capacitors using common Pt electrodes. The capacitors fabricated at 580 o C by applying a PZT seed layer exhibited fatigue-free behavior up to 6.5 x 10 10 switching cycles, a quite stable charge retention profile with time, and comparatively high P r values, all of which assure their suitability for practical FRAM applications. Copyright 2001 American Institute of Physics

Physics based Degradation Modeling and Prognostics of Electrolytic Capacitors under Electrical Overstress Conditions

Data.gov (United States)

National Aeronautics and Space Administration — This paper proposes a physics based degradation modeling and prognostics approach for electrolytic capacitors. Electrolytic capacitors are critical components in...

On battery-less autonomous polygeneration microgrids: Investigation of the combined hybrid capacitors/hydrogen alternative

International Nuclear Information System (INIS)

Kyriakarakos, George; Piromalis, Dimitrios D.; Arvanitis, Konstantinos G.; Dounis, Anastasios I.; Papadakis, George

2015-01-01

Highlights: • A battery-less autonomous polygeneration microgrid is technically feasible. • Laboratory testing of hybrid capacitors. • Investigation of hybrid capacitors utilization along with hydrogen subsystem. - Abstract: The autonomous polygeneration microgrid topology aims to cover holistically the needs in remote areas as far as electrical power, potable water through desalination, fuel for transportation in the form of hydrogen, heating and cooling are concerned. Deep discharge lead acid batteries are mostly used in such systems, associated with specific disadvantages, both technical and environmental. This paper investigated the possibility of replacing the battery bank from a polygeneration microgrid with a hybrid capacitor bank and more intensive utilization of a hydrogen subsystem. Initially commercial hybrid capacitors were tested under laboratory conditions and based on the respective results a case study was performed. The optimized combination of hybrid capacitors and higher hydrogen usage was then investigated through simulations and compared to a polygeneration microgrid featuring deep discharge lead acid batteries. From the results it was clear that it is technically possible to exchange the battery bank with a hybrid capacitor bank and higher hydrogen utilization. From the economic point of view, the current cost of the hybrid capacitors and the hydrogen components is high which leads to higher overall cost in comparison with deep discharge lead acid batteries. Taking into account, though, the decreasing cost prospects and trends of both the hybrid capacitors and the hydrogen components it is expected that this approach will become economically competitive in a few years

Development and experimental study of oil-free capacitor module for plasma focus device

Science.gov (United States)

Sharma, Ravindra Kumar; Sharma, Archana

2017-03-01

This development is concerned with the compact capacitor module for a plasma focus device. Oil-free, non-standard geometry capacitors are designed and developed for high current delivery in sub-microseconds time. Metalized dielectric film based pulse capacitor becomes progressively less viable at currents above 10 kA. It is due to reliability and energy scaling difficulties, based on effects such as vaporization, high resistivity, and end connection. Bipolar electrolytic capacitors are also not preferred due to their limited life and comparatively low peak current delivery. Bi-axially oriented polypropylene (BOPP) film with extended aluminum foil is a combination to deliver moderately high power. But, electrically weak points, relative permittivity, and the edge gap margins have made its adoption difficult. A concept has been developed in lab for implementing the above combination in a less complex and costly manner. This paper concerns the development and testing process techniques for quite different hollow cylindrical, oil-free capacitors (4 μ F , 10 kV, 20 nH). Shot life of 1000 has been experimentally performed on the test bed at its rated energy density level. The technological methods and engineering techniques are now available and utilized for manufacturing and testing of BOPP film based oil-free capacitors.

Location and determination of steps of capacitors in shunt for distribution power lines; Localizacion y determinacion de pasos de capacitores en derivacion para lineas de distribucion

Energy Technology Data Exchange (ETDEWEB)

Pampin Vergara, Gabriela; Sarmiento Uruchurtu, Hector [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2001-07-01

A methodology is presented to determine the optimal location of the capacitor banks in shunt for distribution networks. The proposed tool allows knowing the bank type to install (fixed, disconnect able or of pass), as well as the electrical parameters of the feeder and the economic benefit that the banks of capacitors represent, with a minimum of input data. Its development in a spreadsheet allows the analysis of numerous alternatives in an easy way. The method is based on that the structure of the feeders of distribution is, generally, of radial type, with which, and by means of an iterative process, the optimal location of the capacitor banks in shunt is looked for. The type of bank is determined based of the demand, as well as the number of steps. The results of the analysis in feeders of the network of the central area are shown. [Spanish] Se presenta una metodologia para determinar la localizacion optima de los bancos de capacitores en derivacion en redes de distribucion. La herramienta propuesta permite conocer el tipo de banco a instalar (fijo, desconcectable o de paso), asi como los parametros electricos del alimentador y el beneficio economico que representan los bancos de capacitores, con un minimo de datos de entrada. Su desarrollo en una hoja de calculo permite el analisis de numerosas alternativas de manera facil. El metodo se basa en que la estructura de los alimentadores de distribucion es, por lo general, de tipo radial, con lo cual, y por medio de un proceso iterativo, se busca la localizacion optima de los bancos de capacitores en derivacion. Se determina el tipo de banco en funcion de la demanda, asi como el numero de pasos. Se muestran resultados del analisis en alimentadores de la red del area central.

Total-dose radiation-induced degradation of thin film ferroelectric capacitors

International Nuclear Information System (INIS)

Schwank, J.R.; Nasby, R.D.; Miller, S.L.; Rodgers, M.S.; Dressendorfer, P.V.

1990-01-01

Thin film PbZr y Ti 1-y O 3 (PZT) ferroelectric memories offer the potential for radiation-hardened, high-speed nonvolatile memories with good retention and fatigue properties. In this paper we explore in detail the radiation hardness of PZT ferroelectric capacitors. Ferroelectric capacitors were irradiated using x-ray and Co-60 sources to dose levels up to 16 Mrad(Si). The capacitors were characterized for their memory properties both before and after irradiation. The radiation hardness was process dependent. Three out of four processes resulted in capacitors that showed less than 30% radiation-induced degradation in retained polarization charge and remanent polarization after irradiating to 16 Mrad(Si). On the other hand, one of the processes showed significant radiation-induced degradation in retained polarization charge and remanent polarization at dose levels above 1 Mrad(Si). The decrease in retained polarization charge appears to be due to an alteration of the switching characteristics of the ferroelectric due to changes in the internal fields. The radiation-induced degradation is recoverable by a postirradiation biased anneal and can be prevented entirely if devices are cycled during irradiation. The authors have developed a model to simulate the observed degradation

Evaluation of gamma radiation response of electrolyte, MKP and MKT capacitors in various frequencies

International Nuclear Information System (INIS)

Malekie, Shahryar; Salehpour, Behrooz

2017-01-01

In this experimental work, the effect of gamma irradiation on the capacitance and impedance of some commercial capacitors namely electrolytic, MKP, and MKT capacitors in different radiation doses up to 120 kGy and a wide range of frequencies between 42 Hz and 5 MHz were studied. Results showed that the capacitances of the electrolytic capacitors exhibited a linear decrease by increasing the radiation dose and frequencies, which can be used for high dosimetry purposes, but non-ceramic capacitors as MKP and MKT showed much higher radiation resistance, particularly for the frequencies less than ∝1 MHz.

A Novel Flying Capacitor Transformerless Inverter for Single-Phase Grid Connected Solar Photovoltaic System

DEFF Research Database (Denmark)

Siwakoti, Yam Prasad; Blaabjerg, Frede

2016-01-01

This paper proposes a new single-phase flying capacitor transformerless PV inverter for grid-connected photovoltaic (PV) systems. The neutral of the grid can be directly connected to the negative terminal of the source (PV). It consists of four power switches, one diode, one capacitor and a small...... and some topologies, which requires two times of the peak ac-voltage magnitude) and, (5) the flying capacitor charges every switching cycle, which reduces the size of the required capacitor with switching frequency. In addition, industry standard half bridge module can be used in the new inverter without...

Evaluation of gamma radiation response of electrolyte, MKP and MKT capacitors in various frequencies

Energy Technology Data Exchange (ETDEWEB)

Malekie, Shahryar [Nuclear Science and Technology Research Institute, Karaj (Iran, Islamic Republic of). Radiation Application Research School; Salehpour, Behrooz [Tabriz Univ. (Iran, Islamic Republic of). Faculty of Physics

2017-09-01

In this experimental work, the effect of gamma irradiation on the capacitance and impedance of some commercial capacitors namely electrolytic, MKP, and MKT capacitors in different radiation doses up to 120 kGy and a wide range of frequencies between 42 Hz and 5 MHz were studied. Results showed that the capacitances of the electrolytic capacitors exhibited a linear decrease by increasing the radiation dose and frequencies, which can be used for high dosimetry purposes, but non-ceramic capacitors as MKP and MKT showed much higher radiation resistance, particularly for the frequencies less than ∝1 MHz.

Market Structure and Stock Splits

OpenAIRE

David Michayluk; Paul Kofman

2001-01-01

Enhanced liquidity is one possible motivation for stock splits but empirical research frequently documents declines in liquidity following stock splits. Despite almost thirty years of inquiry, little is known about all the changes in a stock's trading activity following a stock split. We examine how liquidity measures change around more than 2,500 stock splits and find a pervasive decline in most measures. Large stock splits exhibit a more severe liquidity decline than small stock splits, esp...

Neural network for optimal capacitor placement and its impact on power quality in electric distribution systems

International Nuclear Information System (INIS)

Mohamed, A.A.E.S.

2013-01-01

Capacitors are widely installed in distribution systems for reactive power compensation to achieve power and energy loss reduction, voltage regulation and system capacity release. The extent of these benefits depends greatly on how the capacitors are placed on the system. The problem of how to place capacitors on the system such that these benefits are achieved and maximized against the cost associated with the capacitor placement is termed the general capacitor placement problem. The capacitor placement problem has been formulated as the maximization of the savings resulted from reduction in both peak power and energy losses considering capacitor installation cost and maintaining the buses voltage within acceptable limits. After an appropriate analysis, the optimization problem was formulated in a quadratic form. For solving capacitor placement a new combinatorial heuristic and quadratic programming technique has been presented and applied in the MATLAB software. The proposed strategy was applied on two different radial distribution feeders. The results have been compared with previous works. The comparison showed the validity and the effectiveness of this strategy. Secondly, two artificial intelligence techniques for predicting the capacitor switching state in radial distribution feeders have been investigated; one is based on basis Radial Basis Neural Network (RBNN) and the other is based on Adaptive Neuro-Fuzzy Inference System (ANFIS). The ANFIS technique gives better results with a minimum total error compared to RBNN. The learning duration of ANFIS was very short than the neural network case. It implied that ANFIS reaches to the target faster than neural network. Thirdly, an artificial intelligence (RBNN) approach for estimation of transient overvoltage during capacitor switching has been studied. The artificial intelligence approach estimated the transient overvoltages with a minimum error in a short computational time. Finally, a capacitor switching

An innovative ultra-capacitor driven shape memory alloy actuator with an embedded control system

International Nuclear Information System (INIS)

Li, Peng; Song, Gangbing

2014-01-01

In this paper, an innovative ultra-capacitor driven shape memory alloy (SMA) actuator with an embedded control system is proposed targeting high power high-duty cycle SMA applications. The ultra-capacitor, which is capable of delivering massive amounts of instantaneous current in a compact dimension for high power applications, is chosen as the main component of the power supply. A specialized embedded system is designed from the ground up to control the ultra-capacitor driven SMA system. The control of the ultra-capacitor driven SMA is different from that of a regular constant voltage powered SMA system in that the energy and the voltage of the ultra-capacitor decrease as the system load increases. The embedded control system is also different from a computer-based control system in that it has limited computational power, and the control algorithm has to be designed to be simple while effective so that it can fit into the embedded system environment. The problem of a variable voltage power source induced by the use of the ultra-capacitor is solved by using a fuzzy PID (proportional integral and derivative) control. The method of using an ultra-capacitor to drive SMA actuators enabled SMA as a good candidate for high power high-duty cycle applications. The proposed embedded control system provides a good and ready-to-use solution for SMA high power applications. (paper)

Step-down switched-capacitor quasi-resonant PWM converter with continuous conversion ratio

NARCIS (Netherlands)

Turhan, M.; Hendrix, M.A.M.; Duarte, J.L.

2015-01-01

Inherent disadvantages of conventional switched-capacitor converters (SCC) are their discrete conversion ratio and inefficient energy transfer. In order to soften these downsides, a step-down switched-capacitor quasi-resonant PWM converter is proposed. The operation modes and steady-state

Adjustable movable capacitors bank at 20 or 30 MVAr in 115 kV; Banco movil de capacitores ajustable a 20 o 30 MVAr en 115 kV

Energy Technology Data Exchange (ETDEWEB)

Ponce Velez, Marco A; Lopez Velazquez, Juan Jose [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Lopez Tagle, Alfredo; Aragon Garcia, Hector [Comision Federal de Electricidad (Mexico)

1999-07-01

The use of fixed capacitors banks in distribution and transmission systems is a useful tool to compensate the demand of reactive power and the drop of voltage of the power lines. Nevertheless, unforeseen happenings can be originated that could cause decompensation in the system reliability. Due to the previous fact, the Transmission and Transformation Coordinator (CTT) of the Comision Federal de Electricidad (CFE) asked for the design and the construction of a movable bank of capacitors for an emergent compensation of reactive power. In this article it is presented the most relevant of the design, the construction and the operation of the movable bank of capacitors developed in the Instituto de Investigaciones Electricas (IIE). [Spanish] El empleo de bancos capacitadores fijos en los sistemas de distribucion y transmision es una herramienta util para compensar la demanda de reactivos y la caida de tension de las lineas. Sin embargo, se pueden originar imprevistos que descompensan la confiabilidad del sistema. Debido a lo anterior, la Coordinadora de Transmision y Transformacion (CTT) de la Comision Federal de Electricidad (CFE) solicito el diseno y la construccion de un banco movil de capacitores para una compensacion emergente de potencia reactiva. En este articulo se presenta lo mas relevante del diseno, la construccion y la operacion del banco movil de capacitores desarrollado en el Instituto de Investigaciones Electricas (IIE).

Note: Compact high voltage pulse transformer made using a capacitor bank assembled in the shape of primary.

Science.gov (United States)

Shukla, Rohit; Banerjee, Partha; Sharma, Surender K; Das, Rashmita; Deb, Pankaj; Prabaharan, T; Das, Basanta; Adhikary, Biswajit; Verma, Rishi; Shyam, Anurag

2011-10-01

The experimental results of an air-core pulse transformer are presented, which is very compact (capacitor bank that is fabricated in such a way that the capacitor bank with its switch takes the shape of single-turn rectangular shaped primary of the transformer. A high voltage capacitor assembly (pulse-forming-line capacitor, PFL) of 5.1 nF is connected with the secondary of transformer. The transformer output voltage is 160 kV in its second peak appearing in less than 2 μS from the beginning of the capacitor discharge. The primary capacitor bank can be charged up to a maximum of 18 kV, with the voltage delivery of 360 kV in similar capacitive loads.

Pulse Power Capability Of High Energy Density Capacitors Based on a New Dielectric Material

Science.gov (United States)

Winsor, Paul; Scholz, Tim; Hudis, Martin; Slenes, Kirk M.

1999-01-01

A new dielectric composite consisting of a polymer coated onto a high-density metallized Kraft has been developed for application in high energy density pulse power capacitors. The polymer coating is custom formulated for high dielectric constant and strength with minimum dielectric losses. The composite can be wound and processed using conventional wound film capacitor manufacturing equipment. This new system has the potential to achieve 2 to 3 J/cu cm whole capacitor energy density at voltage levels above 3.0 kV, and can maintain its mechanical properties to temperatures above 150 C. The technical and manufacturing development of the composite material and fabrication into capacitors are summarized in this paper. Energy discharge testing, including capacitance and charge-discharge efficiency at normal and elevated temperatures, as well as DC life testing were performed on capacitors manufactured using this material. TPL (Albuquerque, NM) has developed the material and Aerovox (New Bedford, MA) has used the material to build and test actual capacitors. The results of the testing will focus on pulse power applications specifically those found in electro-magnetic armor and guns, high power microwave sources and defibrillators.

A Switched Capacitor Based AC/DC Resonant Converter for High Frequency AC Power Generation

Directory of Open Access Journals (Sweden)

Cuidong Xu

2015-09-01

Full Text Available A switched capacitor based AC-DC resonant power converter is proposed for high frequency power generation output conversion. This converter is suitable for small scale, high frequency wind power generation. It has a high conversion ratio to provide a step down from high voltage to low voltage for easy use. The voltage conversion ratio of conventional switched capacitor power converters is fixed to n, 1/n or −1/n (n is the switched capacitor cell. In this paper, A circuit which can provide n, 1/n and 2n/m of the voltage conversion ratio is presented (n is stepping up the switched capacitor cell, m is stepping down the switching capacitor cell. The conversion ratio can be changed greatly by using only two switches. A resonant tank is used to assist in zero current switching, and hence the current spike, which usually exists in a classical switching switched capacitor converter, can be eliminated. Both easy operation and efficiency are possible. Principles of operation, computer simulations and experimental results of the proposed circuit are presented. General analysis and design methods are given. The experimental result verifies the theoretical analysis of high frequency AC power generation.

Multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes

Science.gov (United States)

Farahmandi, C. Joseph; Dispennette, John M.; Blank, Edward; Kolb, Alan C.

1999-01-19

A single cell, multi-electrode high performance double layer capacitor includes first and second flat stacks of electrodes adapted to be housed in a closeable two-part capacitor case which includes only a single electrolyte seal. Each electrode stack has a plurality of electrodes connected in parallel, with the electrodes of one stack being interleaved with the electrodes of the other stack to form an interleaved stack, and with the electrodes of each stack being electrically connected to respective capacitor terminals. A porous separator sleeve is inserted over the electrodes of one stack before interleaving to prevent electrical shorts between the electrodes. The electrodes are made by folding a compressible, low resistance, aluminum-impregnated carbon cloth, made from activated carbon fibers, around a current collector foil, with a tab of the foils of each electrode of each stack being connected in parallel and connected to the respective capacitor terminal. The height of the interleaved stack is somewhat greater than the inside height of the closed capacitor case, thereby requiring compression of the interleaved electrode stack when placed inside of the case, and thereby maintaining the interleaved electrode stack under modest constant pressure. The closed capacitor case is filled with an electrolytic solution and sealed. A preferred electrolytic solution is made by dissolving an appropriate salt into acetonitrile (CH.sub.3 CN). In one embodiment, the two parts of the capacitor case are conductive and function as the capacitor terminals.

Effects of electrodes on the properties of sol-gel PZT based capacitors in FeRAM

Science.gov (United States)

Zhang, Ming-Ming; Jia, Ze; Ren, Tian-Ling

2009-05-01

The effects of electrodes on the properties of capacitors applied in ferroelectric random access memories (FeRAM) are investigated in this work. Pt and Ir are used as bottom and top electrodes (BE and TE), respectively, in sol-gel Pb(Zr xTi 1-x)O 3 (PZT) based capacitors. Bottom electrodes are found to play a dominant role in the properties of PZT films and capacitors. Capacitors using Pt as bottom electrode have larger remnant polarization (2Pr) than those using Ir which may result from the different orientations of PZT films. The higher Schottky barrier, more dense film and smaller roughness are believed to be the reasons for the better leakage performance of capacitors using Pt as bottom electrodes. Different vacancies types and interface conditions are believed to be the main reasons for the better fatigue (less than 10% initial 2Pr loss after 10 11 fatigue cycles) and better imprint properties of TE/PZT/Ir capacitors. Top electrodes are found to have smaller impact on the properties of capacitors compared with bottom electrodes. A decrease in 2Pr is found when Ir is used as top electrode instead of Pt for PZT/Pt, which is believed to be caused by the stress resulting from lattice mismatch. The different thermal processes that top and bottom electrodes suffered are believed to be the reason for the different impacts they have on capacitors.

Design of constant current charging power supply for J-TEXT ohmic field capacitor banks

International Nuclear Information System (INIS)

Lv Shudong; Zhang Ming; Rao Bo; Yu Kexun; Yang Cheng

2014-01-01

The charging characteristic of the capacitor charging power supply was analyzed with practical series resonant topology. The method that setting two current taps and regulating PWM switching frequency was putted forward with close loop controlling algorithm to charge the multi-group capacitor banks with constant current. A capacitor charging power supply with the max output current 6.5 A and the max output voltage 2000 V is designed. Experimental results show that, this power supply can charge the four capacitor banks to any four different voltages in 1 minute with charging accuracy less than 1%, and meet the requirements of J-TEXT ohmic field power system. (authors)

Effect of Preconditioning and Soldering on Failures of Chip Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander A.

2014-01-01

Soldering of molded case tantalum capacitors can result in damage to Ta205 dielectric and first turn-on failures due to thermo-mechanical stresses caused by CTE mismatch between materials used in the capacitors. It is also known that presence of moisture might cause damage to plastic cases due to the pop-corning effect. However, there are only scarce literature data on the effect of moisture content on the probability of post-soldering electrical failures. In this work, that is based on a case history, different groups of similar types of CWR tantalum capacitors from two lots were prepared for soldering by bake, moisture saturation, and longterm storage at room conditions. Results of the testing showed that both factors: initial quality of the lot, and preconditioning affect the probability of failures. Baking before soldering was shown to be effective to prevent failures even in lots susceptible to pop-corning damage. Mechanism of failures is discussed and recommendations for pre-soldering bake are suggested based on analysis of moisture characteristics of materials used in the capacitors' design.

Quasistationary magnetic field generation with a laser-driven capacitor-coil assembly.

Science.gov (United States)

Tikhonchuk, V T; Bailly-Grandvaux, M; Santos, J J; Poyé, A

2017-08-01

Recent experiments are showing possibilities to generate strong magnetic fields on the excess of 500 T with high-energy nanosecond laser pulses in a compact setup of a capacitor connected to a single turn coil. Hot electrons ejected from the capacitor plate (cathode) are collected at the other plate (anode), thus providing the source of a current in the coil. However, the physical processes leading to generation of currents exceeding hundreds of kiloamperes in such a laser-driven diode are not sufficiently understood. Here we present a critical analysis of previous results and propose a self-consistent model for the high current generation in a laser-driven capacitor-coil assembly. It accounts for three major effects controlling the diode current: the space charge neutralization, the plasma magnetization between the capacitor plates, and the Ohmic heating of the external circuit-the coil-shaped connecting wire. The model provides the conditions necessary for transporting strongly super-Alfvenic currents through the diode on the time scale of a few nanoseconds. The model validity is confirmed by a comparison with the available experimental data.

Dielectric capacitors with three-dimensional nanoscale interdigital electrodes for energy storage.

Science.gov (United States)

Han, Fangming; Meng, Guowen; Zhou, Fei; Song, Li; Li, Xinhua; Hu, Xiaoye; Zhu, Xiaoguang; Wu, Bing; Wei, Bingqing

2015-10-01

Dielectric capacitors are promising candidates for high-performance energy storage systems due to their high power density and increasing energy density. However, the traditional approach strategies to enhance the performance of dielectric capacitors cannot simultaneously achieve large capacitance and high breakdown voltage. We demonstrate that such limitations can be overcome by using a completely new three-dimensional (3D) nanoarchitectural electrode design. First, we fabricate a unique nanoporous anodic aluminum oxide (AAO) membrane with two sets of interdigitated and isolated straight nanopores opening toward opposite planar surfaces. By depositing carbon nanotubes in both sets of pores inside the AAO membrane, the new dielectric capacitor with 3D nanoscale interdigital electrodes is simply realized. In our new capacitors, the large specific surface area of AAO can provide large capacitance, whereas uniform pore walls and hemispheric barrier layers can enhance breakdown voltage. As a result, a high energy density of 2 Wh/kg, which is close to the value of a supercapacitor, can be achieved, showing promising potential in high-density electrical energy storage for various applications.

Ceramic capacitor exhibiting graceful failure by self-clearing, method for fabricating self-clearing capacitor

Science.gov (United States)

Kaufman, David Y [Chicago, IL; Saha, Sanjib [Santa Clara, CA

2006-08-29

A short-resistant capacitor comprises an electrically conductive planar support substrate having a first thickness, a ceramic film deposited over the support substrate, thereby defining a ceramic surface; and a metallic film deposited over the ceramic surface, said film having a second thickness which is less than the first thickness and which is between 0.01 and 0.1 microns.

Thin film barium strontium titanate capacitors for tunable RF front-end applications

NARCIS (Netherlands)

Tiggelman, M.P.J.

2009-01-01

In this thesis, the results of intensive electrical characterization, modeling and the design of hardware with thin film tunable capacitors, i.e., dielectric varactors, has been presented and discussed. Especially the quality factor Q and the tuning ratio of the tunable capacitors have been studied,

Optimal Capacitor Bank Capacity and Placement in Distribution Systems with High Distributed Solar Power Penetration

Energy Technology Data Exchange (ETDEWEB)

Hodge, Brian S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Mather, Barry A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cho, Gyu-Jung [Sungkyunkwan University, Korea; Oh, Yun-Sik [Sungkyunkwan University, Korea; Kim, Min-Sung [Sungkyunkwan University, Korea; Kim, Ji-Soo [Sungkyunkwan University, Korea; Kim, Chul-Hwan [Sungkyunkwan University, Korea

2018-02-01

Capacitor banks have been generally installed and utilized to support distribution voltage during period of higher load or on longer, higher impedance, feeders. Installations of distributed energy resources in distribution systems are rapidly increasing, and many of these generation resources have variable and uncertain power output. These generators can significantly change the voltage profile across a feeder, and therefore when a new capacitor bank is needed analysis of optimal capacity and location of the capacitor bank is required. In this paper, we model a particular distribution system including essential equipment. An optimization method is adopted to determine the best capacity and location sets of the newly installed capacitor banks, in the presence of distributed solar power generation. Finally we analyze the optimal capacitor banks configuration through the optimization and simulation results.

Modeling and fabrication of an RF MEMS variable capacitor with a fractal geometry

KAUST Repository

Elshurafa, Amro M.

2013-08-16

In this paper, we model, fabricate, and measure an electrostatically actuated MEMS variable capacitor that utilizes a fractal geometry and serpentine-like suspension arms. Explicitly, a variable capacitor that possesses a top suspended plate with a specific fractal geometry and also possesses a bottom fixed plate complementary in shape to the top plate has been fabricated in the PolyMUMPS process. An important benefit that was achieved from using the fractal geometry in designing the MEMS variable capacitor is increasing the tuning range of the variable capacitor beyond the typical ratio of 1.5. The modeling was carried out using the commercially available finite element software COMSOL to predict both the tuning range and pull-in voltage. Measurement results show that the tuning range is 2.5 at a maximum actuation voltage of 10V.

Capacitor charging FET switcher with controller to adjust pulse width

Science.gov (United States)

Mihalka, Alex M.

1986-01-01

A switching power supply includes an FET full bridge, a controller to drive the FETs, a programmable controller to dynamically control final output current by adjusting pulse width, and a variety of protective systems, including an overcurrent latch for current control. Power MOSFETS are switched at a variable frequency from 20-50 kHz to charge a capacitor load from 0 to 6 kV. A ferrite transformer steps up the DC input. The transformer primary is a full bridge configuration with the FET switches and the secondary is fed into a high voltage full wave rectifier whose output is connected directly to the energy storage capacitor. The peak current is held constant by varying the pulse width using predetermined timing resistors and counting pulses. The pulse width is increased as the capacitor charges to maintain peak current. A digital ripple counter counts pulses, and after the desired number is reached, an up-counter is clocked. The up-counter output is decoded to choose among different resistors used to discharge a timing capacitor, thereby determining the pulse width. A current latch shuts down the supply on overcurrent due to either excessive pulse width causing transformer saturation or a major bridge fault, i.e., FET or transformer failure, or failure of the drive circuitry.

Compositionally Graded Multilayer Ceramic Capacitors.

Science.gov (United States)

Song, Hyun-Cheol; Zhou, Jie E; Maurya, Deepam; Yan, Yongke; Wang, Yu U; Priya, Shashank

2017-09-27

Multilayer ceramic capacitors (MLCC) are widely used in consumer electronics. Here, we provide a transformative method for achieving high dielectric response and tunability over a wide temperature range through design of compositionally graded multilayer (CGML) architecture. Compositionally graded MLCCs were found to exhibit enhanced dielectric tunability (70%) along with small dielectric losses (filters and power converters.

SUPER-CAPACITOR APPLICATION IN ELECTRICAL POWER CABLE TESTING FACILITIES IN THERMAL ENDURANCE AND MECHANICAL BRACING TESTS

Directory of Open Access Journals (Sweden)

I. V. Oleksyuk

2015-01-01

Full Text Available The current-carrying cores of the electrical power cables should be resistant to effects of short-circuit currents whose values depend on the material of the core, its cross-sectional area, cable insulation properties, environment temperature, and the duration of the short-circuit current flow (1 and 3–4 sec. when tested for thermal endurance and mechanical bracing. The facilities for testing the 10 kV aluminum core cables with short-circuit current shall provide mechanical-bracing current 56,82 kA and thermal endurance current 11,16 kA. Although capacitors provide such values of the testing currents to the best advantage, utilizing conventional capacitor-units will involve large expenditures for erecting and  running a separate building. It is expedient to apply super-capacitors qua the electric power supply for testing facilities, as they are capacitors with double-electrical layer and involve the current values of tens of kilo-amperes.The insulation voltage during short-circuit current testing being not-standardized, it is not banned to apply voltages less than 10 kV when performing short-circuit thermal endurance and mechanical bracing tests for electrical power cables of 10 kV. The super-capacitor voltage variation-in-time graph consists of two regions: capacitive and resistive. The capacitive part corresponds to the voltage change consequent on the energy change in the super-capacitors. The resistive part shows the voltage variation due to the active resistance presence in the super-capacitor.The author offers the algorithm determining the number of super capacitors requisite for testing 10 kV-electrical power cables with short-circuit currents for thermal endurance and mechanical bracing. The paper shows that installation of super-capacitors in the facilities testing the cables with short-circuit currents reduces the area needed for the super-capacitors in comparison with conventional capacitors more than by one order of magnitude.

Redox-capacitor to connect electrochemistry to redox-biology.

Science.gov (United States)

Kim, Eunkyoung; Leverage, W Taylor; Liu, Yi; White, Ian M; Bentley, William E; Payne, Gregory F

2014-01-07

It is well-established that redox-reactions are integral to biology for energy harvesting (oxidative phosphorylation), immune defense (oxidative burst) and drug metabolism (phase I reactions), yet there is emerging evidence that redox may play broader roles in biology (e.g., redox signaling). A critical challenge is the need for tools that can probe biologically-relevant redox interactions simply, rapidly and without the need for a comprehensive suite of analytical methods. We propose that electrochemistry may provide such a tool. In this tutorial review, we describe recent studies with a redox-capacitor film that can serve as a bio-electrode interface that can accept, store and donate electrons from mediators commonly used in electrochemistry and also in biology. Specifically, we (i) describe the fabrication of this redox-capacitor from catechols and the polysaccharide chitosan, (ii) discuss the mechanistic basis for electron exchange, (iii) illustrate the properties of this redox-capacitor and its capabilities for promoting redox-communication between biology and electrodes, and (iv) suggest the potential for enlisting signal processing strategies to "extract" redox information. We believe these initial studies indicate broad possibilities for enlisting electrochemistry and signal processing to acquire "systems level" redox information from biology.

Magnetic and magneto-dielectric properties of magneto-electric field effect capacitor using Cr2O3

OpenAIRE

Takeshi, Yokota; Shotaro, Murata; Takaaki, Kuribayashi; Manabu, Gomi

2008-01-01

We investigated the magnetic and dielectric properties of a metal (Pt)/insulator (Cr_2O_3)/magnetic floating gate (Fe)/tunnel layer (CeO_2)/semiconductor (Si) capacitor. This capacitor shows capacitance-voltage (C-V) properties typical of a Si Metal-Insulator-Semiconductor (MIS) capacitor with hysteresis, which indicates that electrons have been injected into the Fe layer. The capacitor also shows ferromagnetic properties. The C-V curve has a hysteresis window with a clockwise trace. This hys...

A noise level prediction method based on electro-mechanical frequency response function for capacitors.

Science.gov (United States)

Zhu, Lingyu; Ji, Shengchang; Shen, Qi; Liu, Yuan; Li, Jinyu; Liu, Hao

2013-01-01

The capacitors in high-voltage direct-current (HVDC) converter stations radiate a lot of audible noise which can reach higher than 100 dB. The existing noise level prediction methods are not satisfying enough. In this paper, a new noise level prediction method is proposed based on a frequency response function considering both electrical and mechanical characteristics of capacitors. The electro-mechanical frequency response function (EMFRF) is defined as the frequency domain quotient of the vibration response and the squared capacitor voltage, and it is obtained from impulse current experiment. Under given excitations, the vibration response of the capacitor tank is the product of EMFRF and the square of the given capacitor voltage in frequency domain, and the radiated audible noise is calculated by structure acoustic coupling formulas. The noise level under the same excitations is also measured in laboratory, and the results are compared with the prediction. The comparison proves that the noise prediction method is effective.

An RF power amplifier with inter-metal-shuffled capacitor for inter-stage matching in a digital CMOS process

Energy Technology Data Exchange (ETDEWEB)

Feng Xiaoxing; Zhang Xing; Ge Binjie; Wang Xin' an, E-mail: wangxa@szpku.edu.c [Key Laboratory of Integrated Microsystems, Shenzhen Graduate School of Peking University, Shenzhen 518055 (China)

2009-06-01

One challenge of the implementation of fully-integrated RF power amplifiers into a deep submicro digital CMOS process is that no capacitor is available, especially no high density capacitor. To address this problem, a two-stage class-AB power amplifier with inter-stage matching realized by an inter-metal coupling capacitor is designed in a 180-nm digital CMOS process. This paper compares three structures of inter-metal coupling capacitors with metal-insulator-metal (MIM) capacitor regarding their capacitor density. Detailed simulations are carried out for the leakage, the voltage dependency, the temperature dependency, and the quality factor between an inter-metal shuffled (IMS) capacitor and an MIM capacitor. Finally, an IMS capacitor is chosen to perform the inter-stage matching. The techniques are validated via the design and implement of a two-stage class-AB RF power amplifier for an UHF RFID application. The PA occupies 370 x 200 mum{sup 2} without pads in the 180-nm digital CMOS process and outputs 21.1 dBm with 40% drain efficiency and 28.1 dB power gain at 915 MHz from a single 3.3 V power supply.

An RF power amplifier with inter-metal-shuffled capacitor for inter-stage matching in a digital CMOS process

International Nuclear Information System (INIS)

Feng Xiaoxing; Zhang Xing; Ge Binjie; Wang Xin'an

2009-01-01

One challenge of the implementation of fully-integrated RF power amplifiers into a deep submicro digital CMOS process is that no capacitor is available, especially no high density capacitor. To address this problem, a two-stage class-AB power amplifier with inter-stage matching realized by an inter-metal coupling capacitor is designed in a 180-nm digital CMOS process. This paper compares three structures of inter-metal coupling capacitors with metal-insulator-metal (MIM) capacitor regarding their capacitor density. Detailed simulations are carried out for the leakage, the voltage dependency, the temperature dependency, and the quality factor between an inter-metal shuffled (IMS) capacitor and an MIM capacitor. Finally, an IMS capacitor is chosen to perform the inter-stage matching. The techniques are validated via the design and implement of a two-stage class-AB RF power amplifier for an UHF RFID application. The PA occupies 370 x 200 μm 2 without pads in the 180-nm digital CMOS process and outputs 21.1 dBm with 40% drain efficiency and 28.1 dB power gain at 915 MHz from a single 3.3 V power supply.

A lithographically patterned capacitor with horizontal nanowires of length 2.5 mm.

Science.gov (United States)

Yan, Wenbo; Thai, Mya Le; Dutta, Rajen; Li, Xiaowei; Xing, Wendong; Penner, Reginald M

2014-04-09

A symmetrical hybrid capacitor consisting of interdigitated, horizontal nanowires is described. Each of the 750 nanowires within the capacitor is 2.5 mm in length, consisting of a gold nanowire core (40 × ≈200 nm) encapsulated within a hemicylindrical shell of δ-phase MnO2 (thickness = 60-220 nm). These Au@δ-MnO2 nanowires are patterned onto a planar glass surface using lithographically patterned nanowire electrodeposition (LPNE). A power density of 165 kW/kg and energy density of 24 Wh/kg were obtained for a typical nanowire array in which the MnO2 shell thickness was 68 ± 8 nm. Capacitors incorporating these ultralong nanowires lost ≈10% of their capacity rapidly, during the first 20 discharge cycles, and then retained 90% of their maximum capacity for the ensuing 6000 cycles. The ability of capacitors consisting of ultralong Au@δ-MnO2 nanowires to simultaneously deliver high power and high capacity with acceptable cycle life is demonstrated.

Physics Based Electrolytic Capacitor Degradation Models for Prognostic Studies under Thermal Overstress

Science.gov (United States)

Kulkarni, Chetan S.; Celaya, Jose R.; Goebel, Kai; Biswas, Gautam

2012-01-01

Electrolytic capacitors are used in several applications ranging from power supplies on safety critical avionics equipment to power drivers for electro-mechanical actuators. This makes them good candidates for prognostics and health management research. Prognostics provides a way to assess remaining useful life of components or systems based on their current state of health and their anticipated future use and operational conditions. Past experiences show that capacitors tend to degrade and fail faster under high electrical and thermal stress conditions that they are often subjected to during operations. In this work, we study the effects of accelerated aging due to thermal stress on different sets of capacitors under different conditions. Our focus is on deriving first principles degradation models for thermal stress conditions. Data collected from simultaneous experiments are used to validate the desired models. Our overall goal is to derive accurate models of capacitor degradation, and use them to predict performance changes in DC-DC converters.

Splitting methods for split feasibility problems with application to Dantzig selectors

International Nuclear Information System (INIS)

He, Hongjin; Xu, Hong-Kun

2017-01-01

The split feasibility problem (SFP), which refers to the task of finding a point that belongs to a given nonempty, closed and convex set, and whose image under a bounded linear operator belongs to another given nonempty, closed and convex set, has promising applicability in modeling a wide range of inverse problems. Motivated by the increasingly data-driven regularization in the areas of signal/image processing and statistical learning, in this paper, we study the regularized split feasibility problem (RSFP), which provides a unified model for treating many real-world problems. By exploiting the split nature of the RSFP, we shall gainfully employ several efficient splitting methods to solve the model under consideration. A remarkable advantage of our methods lies in their easier subproblems in the sense that the resulting subproblems have closed-form representations or can be efficiently solved up to a high precision. As an interesting application, we apply the proposed algorithms for finding Dantzig selectors, in addition to demonstrating the effectiveness of the splitting methods through some computational results on synthetic and real medical data sets. (paper)

A quick method to determine the capacitance characteristics of thin layer X5R multilayer capacitors

NARCIS (Netherlands)

Mikkenie, R.; Steigelmann, O.; Groen, W.A.; ten Elshof, Johan E.

2012-01-01

The effect of Y2O3 concentration on the dielectric properties of ceramic disc capacitors and multilayer capacitors containing 50 dielectric layers with an approximate thickness of 3 μm were investigated. The relative permittivity and temperature coefficient of capacity of multilayer capacitors at

A quick method to determine the capacitance characteristics of thin layer X5R multilayer capacitors

NARCIS (Netherlands)

Mikkenie, R.; Steigelmann, O.; Groen, W.A.; Elshof, J.E. ten

2012-01-01

The effect of Y2O3 concentration on the dielectric properties of ceramic disc capacitors and multilayer capacitors containing 50 dielectric layers with an approximate thickness of 3µm were investigated. The relative permittivity and temperature coefficient of capacity of multilayer capacitors at low

Improved Battery Charger Circuit Utilizing Reduced DC-link Capacitors

Directory of Open Access Journals (Sweden)

Vencislav Valchev

2017-11-01

Full Text Available The article presents a comparison of advantages and disadvantages of a battery charger circuit with and without the use of DC-link capacitors in it. The specific application requirements, namely ultra-light electric vehicles, are set as lightness, efficiency and robustness of the design. Prove of greater reliability and improvement on maintenance costs without significant decrease in the quality of charging process with the removal of DC-link capacitors in rectifier and boost converter circuits is accomplished. The proposed circuit parameters are analyzed by carried out simulations.

RF MEMS Fractal Capacitors With High Self-Resonant Frequencies

KAUST Repository

Elshurafa, Amro M.

2012-07-23

This letter demonstrates RF microelectromechanical systems (MEMS) fractal capacitors possessing the highest reported self-resonant frequencies (SRFs) in PolyMUMPS to date. Explicitly, measurement results show SRFs beyond 20 GHz. Furthermore, quality factors higher than 4 throughout a band of 1-15 GHz and reaching as high as 28 were achieved. Additional benefits that are readily attainable from implementing fractal capacitors in MEMS are discussed, including suppressing residual stress warping, eliminating the need for etching holes, and reducing parasitics. The latter benefits were acquired without any fabrication intervention. © 2011 IEEE.

Coded Splitting Tree Protocols

DEFF Research Database (Denmark)

Sørensen, Jesper Hemming; Stefanovic, Cedomir; Popovski, Petar

2013-01-01

This paper presents a novel approach to multiple access control called coded splitting tree protocol. The approach builds on the known tree splitting protocols, code structure and successive interference cancellation (SIC). Several instances of the tree splitting protocol are initiated, each...... instance is terminated prematurely and subsequently iterated. The combined set of leaves from all the tree instances can then be viewed as a graph code, which is decodable using belief propagation. The main design problem is determining the order of splitting, which enables successful decoding as early...

A Reliability Model for Ni-BaTiO3-Based (BME) Ceramic Capacitors

Science.gov (United States)

Liu, Donhang

2014-01-01

The evaluation of multilayer ceramic capacitors (MLCCs) with base-metal electrodes (BMEs) for potential NASA space project applications requires an in-depth understanding of their reliability. The reliability of an MLCC is defined as the ability of the dielectric material to retain its insulating properties under stated environmental and operational conditions for a specified period of time t. In this presentation, a general mathematic expression of a reliability model for a BME MLCC is developed and discussed. The reliability model consists of three parts: (1) a statistical distribution that describes the individual variation of properties in a test group of samples (Weibull, log normal, normal, etc.), (2) an acceleration function that describes how a capacitors reliability responds to external stresses such as applied voltage and temperature (All units in the test group should follow the same acceleration function if they share the same failure mode, independent of individual units), and (3) the effect and contribution of the structural and constructional characteristics of a multilayer capacitor device, such as the number of dielectric layers N, dielectric thickness d, average grain size r, and capacitor chip size S. In general, a two-parameter Weibull statistical distribution model is used in the description of a BME capacitors reliability as a function of time. The acceleration function that relates a capacitors reliability to external stresses is dependent on the failure mode. Two failure modes have been identified in BME MLCCs: catastrophic and slow degradation. A catastrophic failure is characterized by a time-accelerating increase in leakage current that is mainly due to existing processing defects (voids, cracks, delamination, etc.), or the extrinsic defects. A slow degradation failure is characterized by a near-linear increase in leakage current against the stress time; this is caused by the electromigration of oxygen vacancies (intrinsic defects). The

Compensación de potencia reactiva mediante bancos asimétricos de capacitores; Reactive Power Compensation by Unbalanced Capacitor Banks

Directory of Open Access Journals (Sweden)

Ignacio Pérez Abril

2011-02-01

Full Text Available A pesar de que los sistemas de distribución primaria y secundaria son desbalanceados por naturaleza, lacompensación de potencia reactiva en estos sistemas, se realiza comúnmente mediante bancos decondensadores trifásicos balanceados. En este trabajo se presenta la formulación general para el problemade compensación de potencia reactiva en sistemas desbalanceados mediante bancos de condensadoresdesbalanceados. Se presentan cuatro ejemplos de compensación en el secundario de bancos desbalanceadosde transformadores monofásicos. Todos los ejemplos muestran que la compensación por bancosdesbalanceados de capacitores incrementa los beneficios con respecto al uso de bancos balanceados  In spite of the fact that primary and secondary distribution systems are unbalanced by nature, thereactive power compensation on these systems is commonly developed by the use of balanced capacitorbanks. In this paper, the general formulation for the reactive power compensation problem onunbalanced systems with unbalanced capacitor banks is developed. Four examples of reactive powercompensation on the secondary of unbalanced three-phase transformers banks are presented. All theexamples show that the compensation by unbalanced capacitor banks increases the active power lossessaving as well as reduce the transformer’s load and contributes to balance the line currents when the loadis unbalanced.

DC-Voltage Fluctuation Elimination Through a DC-Capacitor Current Control for DFIG Converters Under Unbalanced Grid Voltage Conditions

DEFF Research Database (Denmark)

Liu, Changjin; Xu, Dehong; Zhu, Nan

2013-01-01

Unbalanced grid voltage causes a large second-order harmonic current in the dc-link capacitors as well as dc-voltage fluctuation, which potentially will degrade the lifespan and reliability of the capacitors in voltage source converters. This paper proposes a novel dc-capacitor current control...... method for a grid-side converter (GSC) to eliminate the negative impact of unbalanced grid voltage on the dc-capacitors. In this method, a dc-capacitor current control loop, where a negative-sequence resonant controller is used to increase the loop gain, is added to the conventional GSC current control...... loop. The rejection capability to the unbalanced grid voltage and the stability of the proposed control system are discussed. The second-order harmonic current in the dc capacitor as well as dc-voltage fluctuation is very well eliminated. Hence, the dc capacitors will be more reliable under unbalanced...

Guidelines for Selection, Screening and Qualification of Low-Voltage Commercial Multilayer Ceramic Capacitors for Space Programs

Science.gov (United States)

Teverovsky, Alexander A.

2012-01-01

This document has been developed in the course of NASA Electronic Parts and Packaging (NEPP) program and is not an official endorsement of the insertion of commercial capacitors in space programs or an established set of requirements for their testing. The purpose of this document is to suggest possible ways for selection, screening, and qualification of commercial capacitors for NASA projects and open discussions in the parts engineering community related to the use of COTS ceramic capacitors. This guideline is applicable to commercial surface mount chip, simple parallel plate design, multi-layer ceramic capacitors (MLCCs) rated to voltages of 100V and less. Parts with different design, e.g. low inductance ceramic capacitors (LICA), land grid array (LGA) etc., might need additional testing and tailoring of the requirements described in this document. Although the focus of this document is on commercial MLCCs, many procedures discussed below would be beneficial for military-grade capacitors

Integrated hybrid switched-capacitor converter for LED drivers in 180 nm CMOS

NARCIS (Netherlands)

Castellanos Rodriguez, J.; Delos, J.; Hendrix, M.A.M.; Van Roermund, A.; Cantatore, E.

2016-01-01

This paper presents a LED driver based on a new Hybrid-Switched Capacitor Converter (H-SCC) operating in the MHz range, which uses the internal pulsed nodes of a Dickson converter and an LC output network to provide output current dimming. The converter is implemented using 5V integrated capacitors

Design and fabrication of a continuously tuned capacitor by microfluidic actuation

Science.gov (United States)

Habbachi, Nizar; Boussetta, Hatem; Boukabache, Ali; Adel Kallala, Mohamed; Pons, Patrick; Besbes, Kamel

2018-03-01

This paper presents the design and fabrication of a continuously tunable RF MEMS capacitor using micro fluidics as a tuning parameter. The impedance variation principle is based on the modification of the capacitor gap permittivity produced by the presence of deionized (DI) water and its displacement in a channel inserted between electrodes. In addition, the electric field distribution changes in an equiponderant way according to the DI water positions in the channel. This change modifies the capacitive coupling, the stored energy and, consequently, the self-resonant frequency. The fabrication process is based on two parts: metallic paths having a spiral form, and obtained by electroplating a 7 µm thick gold layer to constitute electrodes; and fluidic channels, realized by super imposing two SU-8 films. The measurements show a nonlinear variation of the capacitor value according to the water positions. The tuning range is very large, reaching to 4650% for capacitance, and 335% for resonant frequency. However, the quality factor reaches Q max  =  79 at 550 MHz if the capacitor is empty and decreases with the fluid displacement to Q min  =  3.13.

Fringe Capacitance of a Parallel-Plate Capacitor.

Science.gov (United States)

Hale, D. P.

1978-01-01

Describes an experiment designed to measure the forces between charged parallel plates, and determines the relationship among the effective electrode area, the measured capacitance values, and the electrode spacing of a parallel plate capacitor. (GA)

Modeling and fabrication of an RF MEMS variable capacitor with a fractal geometry

KAUST Repository

Elshurafa, Amro M.; Ho, P.H.; Salama, Khaled N.

2013-01-01

capacitor is increasing the tuning range of the variable capacitor beyond the typical ratio of 1.5. The modeling was carried out using the commercially available finite element software COMSOL to predict both the tuning range and pull-in voltage. Measurement

The influence of capacitor banks on transformer load current

Directory of Open Access Journals (Sweden)

Jović Aleksandar S.

2017-01-01

Full Text Available This paper deals with the influence of capacitor banks used for reactive energy compensation on total load current of 10/0,4 kV/kV distribution transformers. The analysis regards distribution area of Leskovac which comprehends town Leskovac and nearby settlements. Differently from previously published references that treat excessively reactive energy consumption, the value of reactive power on low voltage side of transformer taking into account the presence of capacitor banks is observed primarily in this paper. Both theoretically possible cases are restated on the basis of measurements: the compensation is adequate or inadequate. The cases of insufficient compensation and overcompensation are regarded to be inadequate compensation. The adequate compensation is achieved when reactive power oscillates around 0 kvar. The special case of adequate compensation, called conditionally adequate compensation, is introduced. For all four cases that describe reactive energy compensation, the calculation results of relative change of low voltage transformer current in the presence of capacitor banks, in comparison to the current without installed banks are presented.

Capacitor Property and Leakage Current Mechanism of ZrO2 Thin Dielectric Films Prepared by Anodic Oxidation

Science.gov (United States)

Kamijyo, Masahiro; Onozuka, Tomotake; Shinkai, Satoko; Sasaki, Katsutaka; Yamane, Misao; Abe, Yoshio

2003-07-01

Polycrystalline ZrO2 thin film capacitors were prepared by anodizing sputter-deposited Zr films. Electrical measurements are performed for the parallel-plate anodized capacitors with an Al-ZrO2-Zr (metal-insulator-metal) structure, and a high capacitance density (0.6 μF/cm2) and a low dielectric loss of nearly 1% are obtained for a very thin-oxide capacitor anodized at 10 V. In addition, the leakage current density of this capacitor is about 1.8 × 10-8 A/cm2 at an applied voltage of 5 V. However, the leakage current is somewhat larger than that of a low-loss HfO2 capacitor. The leakage current density (J) of ZrO2 capacitors as a function of applied electric field (E) was investigated for several capacitors with different oxide thicknesses, by plotting \\ln(J) vs E1/2 curves. As a result, it is revealed that the conduction mechanism is due to the Poole-Frenkel effect, irrespective of the oxide thickness.

MIM capacitors with various Al2O3 thicknesses for GaAs RFIC application

International Nuclear Information System (INIS)

Zhou Jiahui; Xu Wenjun; Li Qi; Li Simin; He Zhiyi; Li Haiou; Chang Hudong; Liu Honggang; Liu Guiming

2015-01-01

The impact of various thicknesses of Al 2 O 3 metal—insulator—metal (MIM) capacitors on direct current and radio frequency (RF) characteristics is investigated. For 20 nm Al 2 O 3 , the fabricated capacitor exhibits a high capacitance density of 3850 pF/mm 2 and acceptable voltage coefficients of capacitance of 681 ppm/V 2 at 1 MHz. An outstanding VCC-α of 74 ppm/V 2 at 1 MHz, resonance frequency of 8.2 GHz and Q factor of 41 at 2 GHz are obtained by 100 nm Al 2 O 3 MIM capacitors. High-performance MIM capacitors using GaAs process and atomic layer deposition Al 2 O 3 could be very promising candidates for GaAs RFIC applications. (paper)

A General Reliability Model for Ni-BaTiO3-Based Multilayer Ceramic Capacitors

Science.gov (United States)

Liu, Donhang

2014-01-01

The evaluation of multilayer ceramic capacitors (MLCCs) with Ni electrode and BaTiO3 dielectric material for potential space project applications requires an in-depth understanding of their reliability. A general reliability model for Ni-BaTiO3 MLCC is developed and discussed. The model consists of three parts: a statistical distribution; an acceleration function that describes how a capacitor's reliability life responds to the external stresses, and an empirical function that defines contribution of the structural and constructional characteristics of a multilayer capacitor device, such as the number of dielectric layers N, dielectric thickness d, average grain size, and capacitor chip size A. Application examples are also discussed based on the proposed reliability model for Ni-BaTiO3 MLCCs.

Evaluation of Mandibular Anatomy Associated With Bad Splits in Sagittal Split Ramus Osteotomy of Mandible.

Science.gov (United States)

Wang, Tongyue; Han, Jeong Joon; Oh, Hee-Kyun; Park, Hong-Ju; Jung, Seunggon; Park, Yeong-Joon; Kook, Min-Suk

2016-07-01

This study aimed to identify risk factors associated with bad splits during sagittal split ramus osteotomy by using three-dimensional computed tomography. This study included 8 bad splits and 47 normal patients without bad splits. Mandibular anatomic parameters related to osteotomy line were measured. These included anteroposterior width of the ramus at level of lingula, distance between external oblique ridge and lingula, distance between sigmoid notch and inferior border of mandible, mandibular angle, distance between inferior outer surface of mandibular canal and inferior border of mandible under distal root of second molar (MCEM), buccolingual thickness of the ramus at level of lingula, and buccolingual thickness of the area just distal to first molar (BTM1) and second molar (BTM2). The incidence of bad splits in 625 sagittal split osteotomies was 1.28%. Compared with normal group, bad split group exhibited significantly thinner BTM2 and shorter sigmoid notch and inferior border of mandible (P bad splits. These anatomic data may help surgeons to choose the safest surgical techniques and best osteotomy sites.

Harmonic Resonance in Power Transmission Systems due to the Addition of Shunt Capacitors

Science.gov (United States)

Patil, Hardik U.

Shunt capacitors are often added in transmission networks at suitable locations to improve the voltage profile. In this thesis, the transmission system in Arizona is considered as a test bed. Many shunt capacitors already exist in the Arizona transmission system and more are planned to be added. Addition of these shunt capacitors may create resonance conditions in response to harmonic voltages and currents. Such resonance, if it occurs, may create problematic issues in the system. It is main objective of this thesis to identify potential problematic effects that could occur after placing new shunt capacitors at selected buses in the Arizona network. Part of the objective is to create a systematic plan for avoidance of resonance issues. For this study, a method of capacitance scan is proposed. The bus admittance matrix is used as a model of the networked transmission system. The calculations on the admittance matrix were done using Matlab. The test bed is the actual transmission system in Arizona; however, for proprietary reasons, bus names are masked in the thesis copy intended for the public domain. The admittance matrix was obtained from data using the PowerWorld Simulator after equivalencing the 2016 summer peak load (planning case). The full Western Electricity Coordinating Council (WECC) system data were used. The equivalencing procedure retains only the Arizona portion of the WECC. The capacitor scan results for single capacitor placement and multiple capacitor placement cases are presented. Problematic cases are identified in the form of 'forbidden response. The harmonic voltage impact of known sources of harmonics, mainly large scale HVDC sources, is also presented. Specific key results for the study indicated include: (1) The forbidden zones obtained as per the IEEE 519 standard indicates the bus 10 to be the most problematic bus. (2) The forbidden zones also indicate that switching values for the switched shunt capacitor (if used) at bus 3 should be

Characterization of micro-resonator based on enhanced metal insulator semiconductor capacitor for glucose recognition.

Science.gov (United States)

Dhakal, Rajendra; Kim, E S; Jo, Yong-Hwa; Kim, Sung-Soo; Kim, Nam-Young

2017-03-01

We present a concept for the characterization of micro-fabricated based resonator incorporating air-bridge metal-insulator-semiconductor (MIS) capacitor to continuously monitor an individual's state of glucose levels based on frequency variation. The investigation revealed that, the micro-resonator based on MIS capacitor holds considerable promise for implementation and recognition as a glucose sensor for human serum. The discrepancy in complex permittivity as a result of enhanced capacitor was achieved for the detection and determination of random glucose concentration levels using a unique variation of capacitor that indeed results in an adequate variation of the resonance frequency. Moreover, the design and development of micro-resonator with enhanced MIS capacitor generate a resolution of 112.38 × 10 -3 pF/mg/dl, minimum detectable glucose level of 7.45mg/dl, and a limit of quantification of 22.58mg/dl. Additionally, this unique approach offers long-term reliability for mediator-free glucose sensing with a relative standard deviation of less than 0.5%. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Reliability Modeling Development and Its Applications for Ceramic Capacitors with Base-Metal Electrodes (BMEs)

Science.gov (United States)

Liu, Donhang

2014-01-01

This presentation includes a summary of NEPP-funded deliverables for the Base-Metal Electrodes (BMEs) capacitor task, development of a general reliability model for BME capacitors, and a summary and future work.

A Thermal Runaway Failure Model for Low-Voltage BME Ceramic Capacitors with Defects

Science.gov (United States)

Teverovsky, Alexander

2017-01-01

Reliability of base metal electrode (BME) multilayer ceramic capacitors (MLCCs) that until recently were used mostly in commercial applications, have been improved substantially by using new materials and processes. Currently, the inception of intrinsic wear-out failures in high quality capacitors became much greater than the mission duration in most high-reliability applications. However, in capacitors with defects degradation processes might accelerate substantially and cause infant mortality failures. In this work, a physical model that relates the presence of defects to reduction of breakdown voltages and decreasing times to failure has been suggested. The effect of the defect size has been analyzed using a thermal runaway model of failures. Adequacy of highly accelerated life testing (HALT) to predict reliability at normal operating conditions and limitations of voltage acceleration are considered. The applicability of the model to BME capacitors with cracks is discussed and validated experimentally.

Contribution to dimensioning a pack of super-capacitors for 12/42 V application

Energy Technology Data Exchange (ETDEWEB)

Rafik, F.; Karmous, M. [Ecole d' Ingenieurs de l' Arc Jurassien, CH (Switzerland); Gualous, H.; Berthon, A. [Universite de Franche-Comte, Lab. en Electronique, Electrotechnique et Systemes (L2ES), UTBM, 90 - Belfort (France); Gallay, R. [Maxwell Technologies, CH (Switzerland)

2004-07-01

Increase power demands on automotive are making current 12/14 V electrical systems inadequate. The total power demand will triple in some cars from 800 W today to an average of 2500 W and into kW range for peak demand in the future. Super-capacitor can be used for energy storage and for peak power requirement in order to increase the efficiency and the life cycle of the system. However, the sizing of energy storage with super-capacitors is very important for embedded applications, because of the weight and the volume of the system. This paper presents a sizing method of a pack of super-capacitors. The proposed method is based on the power and energy demand. In order to validate this method, a model of the Maxwell cell BCAP0010 of super-capacitors is presented and implemented in the SIMPLORER software. (authors)

Random Vibration Testing of Advanced Wet Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander

2015-01-01

Advanced wet tantalum capacitors allow for improved performance of power supply systems along with substantial reduction of size and weight of the systems that is especially beneficial for space electronics. Due to launch-related stresses, acceptance testing of all space systems includes random vibration test (RVT). However, many types of advanced wet tantalum capacitors cannot pass consistently RVT at conditions specified in MIL-PRF-39006, which impedes their use in space projects. This requires a closer look at the existing requirements, modes and mechanisms of failures, specifics of test conditions, and acceptance criteria. In this work, different lots of advanced wet tantalum capacitors from four manufacturers have been tested at step stress random vibration conditions while their currents were monitored before, during, and after the testing. It has been shown that the robustness of the parts and their reliability are mostly due to effective self-healing processes and limited current spiking or minor scintillations caused by RVT do not increase the risk of failures during operation. A simple model for scintillations events has been used to simulate current spiking during RVT and optimize test conditions. The significance of scintillations and possible effects of gas generation have been discussed and test acceptance criteria for limited current spiking have been suggested.

Pit and fissure sealants for preventing dental decay in the permanent teeth of children and adolescents

DEFF Research Database (Denmark)

Ahovuo-Saloranta, Anneli; Hiiri, Anne; Nordblad, Anne

2008-01-01

BACKGROUND: Although pit and fissure sealants are effective in preventing caries, their efficacy may be related to the caries prevalence in the population. OBJECTIVES: The primary objective of this review was to evaluate the caries prevention of pit and fissure sealants in children and adolescents...... for comparison of sealant versus sealant. Five split-mouth studies and one parallel group study with 5 to 10 year old children found a significant difference in favour of second or third generation resin-based sealants on first permanent molars, compared to a control without sealant, with a pooled RR of 0.13 (95...... sealant group; 27% of sealed surfaces were decayed compared to 77% of surfaces without sealant.The results of the studies comparing different sealant materials were conflicting. AUTHORS' CONCLUSIONS: Sealing is a recommended procedure to prevent caries of the occlusal surfaces of permanent molars...

Transparent capacitors with hybrid ZnO:Al and Ag nanowires as electrodes

International Nuclear Information System (INIS)

Zhang, Guozhen; Wu, Hao; Wang, Xiao; Wang, Ti; Liu, Chang

2016-01-01

Transparent conducting films with a composite structure of AlZnO–Ag nanowires (AgNWs) have been prepared by atomic layer deposition. The sheet resistance was reduced from 120 to 9 Ω when the AgNW networks were involved. Transparent capacitors with Al_2O_3–TiO_2–Al_2O_3 dielectrics were fabricated on the composite electrodes and demonstrated a capacitance density of 10.1 fF μm"−"2, which was significantly higher than that of capacitors with AlZnO electrodes (8.8 fF μm"−"1). The capacitance density remained almost unchanged in a broad frequency range from 3 kHz to 1 MHz. Moreover, a low leakage current density of 2.4 × 10"−"7 A cm"−"2 at 1 V was achieved. Transparent and flexible capacitors were also fabricated using the composite electrodes, and demonstrated an improved bendability. The transparent capacitors showed an average optical transmittance over 70% in the visible range, and thus open the door to practical applications in transparent integrated circuits. (paper)

Charge and Energy Stored in a Capacitor

Science.gov (United States)

Kraftmakher, Yaakov

2012-01-01

Using a data-acquisition system, the charge and energy stored in a capacitor are measured and displayed during the charging/discharging process. The experiment is usable as a laboratory work and/or a lecture demonstration. (Contains 3 figures.)

Energy-Storing Structures: Composite Capacitors and Batteries

Science.gov (United States)

2012-07-30

circuit board (PCB) prepreg C electrode dielectric Autoclave-processed structural capacitor • Objective: High energy density, scalable...Continued scaling (lab safety limit  100 J) – Beyond commercial FR4 prepreg  high dielectric additives, super- clean prepregging

Capacitor Monitoring for Modular Multilevel Converters

DEFF Research Database (Denmark)

Deng, Fujin; Liu, Dong; Wang, Yanbo

2017-01-01

). The capacitor monitoring in each SM of the MMC is an important issue, which would affect the performance of the MMC. This paper proposed an effective monitoring method for the capacitance in each SM of the MMC. The proposed method reveals the relationship between the arm average capacitance and the capacitance...

Study on the KM capacitor base thermometers in the 42-273 K range

International Nuclear Information System (INIS)

Luzganov, V.S.; Mats'ko, A.A.

1988-01-01

Thermometric characteristics of the KM-5a-HZ0 monolithic capacitors in the 42-273 K temperature range are studied. Capacitors capacitance - temperature relation is considered in details. The data reproducibility after 5, 23, 34, 50, 51 and 57 days is studied, the accuracy of temperature measurements by the given thermometers is determined. Recommendations on selection of cpacitors, suitable for application as thermometer, are given. These capacitors permit temperature measurement in the 42-225 K range with the error of ± 0.5 K, and above 225 K the error is ± 1K. 8 refs.; 1 fig.; 1 tab

Simulation evaluation of capacitor bank impact on increasing supply current for alumunium production

Science.gov (United States)

Hasan, S.; Badra, K.; Dinzi, R.; Suherman

2018-03-01

DC current supply to power the electrolysis process in producing aluminium at PT Indonesia Asahan Aluminium (Persero) is about 193 kA. At this condition, the load voltage regulator (LVR) transformer generates 0.89 lagging power factor. By adding the capacitor bank to reduce the harmonic distortion, it is expected that the supply current will increase. This paper evaluates capacitor bank installation impact on the system by using ETAP 12.0 simulation. It has been obtained that by installing 90 MVAR capacitor bank in the secondary part of LVR, the power factor is corrected about 8% and DC current increases about 13.5%.

Composite magnetorheological elastomers as dielectrics for plane capacitors: Effects of magnetic field intensity

Directory of Open Access Journals (Sweden)

Maria Balasoiu

Full Text Available The fabrication of composite magnetorheological elastomers (MRECs based on silicone rubber, carbonyl iron microparticles (10% vol. and polyurethane elastomer doped with 0%, 10% and 20% volume concentration TiO2 microparticles is presented. The obtained MRECs have the shape of thin foils and are used as dielectric materials for manufacturing plane capacitors. Using the plane capacitor method and expression of capacitance as a function of magnetic field intensity, combined with linear elasticity theory, the static magnetoelastic model of the composite is obtained and analyzed. Keywords: Magnetorheological elastomer, TiO2 microparticles, Silicone rubber, Carbonyl iron, Plane capacitor, Magnetoelasticity

Digital Control of a power conditioner for fuel cell/super-capacitor hybrid system

DEFF Research Database (Denmark)

Caballero, Juan C Trujillo; Gomis-Bellmunt, Oriol; Montesinos-Miracle, Daniel

2014-01-01

This article proposes a digital control scheme to operate a proton exchange membrane fuel cell module of 1.2 kW and a super-capacitor through a DC/DC hybrid converter. A fuel cell has been proposed as a primary source of energy, and a super-capacitor has been proposed as an auxiliary source...... of energy. Experimental validation of the system implemented in the laboratory is provided. Several tests have been performed to verify that the system achieves excellent output voltage (V0) regulation and super-capacitor voltage (V SC) control under disturbances from fuel cell power (PFC) and output power...

Carbon-Based Fibrous EDLC Capacitors and Supercapacitors

Directory of Open Access Journals (Sweden)

C. Lekakou

2011-01-01

Full Text Available This paper investigates electrochemical double-layer capacitors (EDLCs including two alternative types of carbon-based fibrous electrodes, a carbon fibre woven fabric (CWF and a multiwall carbon nanotube (CNT electrode, as well as hybrid CWF-CNT electrodes. Two types of separator membranes were also considered. An organic gel electrolyte PEO-LiCIO4-EC-THF was used to maintain a high working voltage. The capacitor cells were tested in cyclic voltammetry, charge-discharge, and impedance tests. The best separator was a glass fibre-fine pore filter. The carbon woven fabric electrode and the corresponding supercapacitor exhibited superior performance per unit area, whereas the multiwall carbon nanotube electrode and corresponding supercapacitor demonstrated excellent specific properties. The hybrid CWF-CNT electrodes did not show a combined improved performance due to the lack of carbon nanotube penetration into the carbon fibre fabric.

GUARANTEEING THE TROUBLE-FREE OPERATION OF CAPACITOR BANKS IN POWER-SUPPLY SYSTEMS OF INDUSTRIAL ENTERPRISES

Directory of Open Access Journals (Sweden)

D.A. Gapon

2016-03-01

Full Text Available Purpose. The problem of resonance phenomena in power systems of industrial enterprises using capacitor banks for reactive power compensation was detected. Circuit of the capacitor banks tier to downshift main substation tires is present. But there is no common algorithm to calculate and avoid such trouble. The main goal of this article is to introduce some basics for power supply systems with possible resonant circuits engineering. Methodology. At the first step the data on the change of the current in the chemical company network when changing capacitor banks value are received. For these purposes the oscilloscope function of digital protection relay was used. Current data samples were analyzed by spectrum detection software. Most significant levels of the 3rd and 5th harmonics were achieved. Comparison of harmonic distortion levels with and without capacitor bank is given. Results. Achieved data allow making conclusion about overloading reasons of capacitor banks while higher harmonics currents presence. A voltage and current harmonious composition measuring in the absence of power quality analyzers using digital protection relay terminals or emergencies registers are proposed. The necessity of power quality monitoring near capacitor banks connections to avoid resonance phenomena (current and voltage resonance in industrial power supply systems is proven. The control algorithm of capacitor banks to provide electromagnetic compatibility, while various modes of nonlinear load operation is given. Originality. Using of digital protection relay oscilloscoping for current resonant detection can allow to significally reduce time and cost of solution. Replacement parallel circuit comprising a branch and one active-inductive load to another branch network in the presence of higher harmonics source are proposed. Practical value. A sequence for measuring the levels of harmonic components at the connections of capacitor banks in the absence of specialized

Two-layer radio frequency MEMS fractal capacitors in PolyMUMPS for S-band applications

KAUST Repository

Elshurafa, Amro M.; Salama, Khaled N.

2012-01-01

In this Letter, the authors fabricate for the first time MEMS fractal capacitors possessing two layers and compare their performance characteristics with the conventional parallel-plate capacitor and previously reported state-of-the-art single

Lithium-ion storage capacitors achieved by CVD graphene/TaC/Ta-wires and carbon hollow spheres

International Nuclear Information System (INIS)

Zhao, Liwei; Li, Hongji; Li, Mingji; Xu, Sheng; Li, Cuiping; Qu, Changqing; Zhang, Lijun; Yang, Baohe

2016-01-01

Highlights: • Graphene/TaC/Ta wire electrode was prepared by CVD. • Carbon hollow spheres as a solid electrolyte were prepared by hydrothermal. • Specific capacitance of assembled capacitor reached 593 F g −1 at 10 A g −1 . • The capacitor provided high energy and power densities (132 W h kg −1 /3.17 kW kg −1 ). • The hybrid capacitor also exhibited a high stability during long endurance tests. - Abstract: Lithium-ion storage capacitors were assembled using graphene/tantalum carbide/tantalum wire electrodes and carbon hollow spheres as electrolyte. The graphene/tantalum carbide layers were prepared by electron-assisted hot filament chemical vapor deposition; the carbon hollow spheres were synthesized by hydrothermal reaction and pyrolysis treatment. The specific capacitance of the capacitor was 593 F g −1 at a current density of 10 A g −1 . The capacitor showed excellent cycling stability, retaining 91.2% of its initial capacitance after 8000 cycles. Moreover, the capacitor provided a high specific energy density of 132 W h kg −1 at a high power density of 3.17 kW kg −1 . The high energy density is attributed to the widened operation window ranging from 0 to 3.0 V. The graphene layer of the electrode and carbon hollow spheres in electrolyte synergistic affect influence on the electrochemical performance of the capacitor are discussed. In addition, the use of a low-cost lithium salt, lithium chloride, is also featured in this paper.

Prognostic Techniques for Capacitor Degradation and Health Monitoring

Data.gov (United States)

National Aeronautics and Space Administration — This paper discusses our initial efforts in constructing physics of failure models for electrolytic capacitors subjected to electrical stressors in DC-DC power...

Investigation about decoupling capacitors of PMT voltage divider effects on neutron-gamma discrimination

International Nuclear Information System (INIS)

Divani, Nazila; Firoozabadi, Mohammad M.; Bayat, Esmail

2014-01-01

Scintillators are almost used in any nuclear laboratory. These detectors combine of scintillation materials, PMT and a voltage divider. Voltage dividers are different in resistive ladder design. But the effect of decoupling capacitors and damping resistors haven’t discussed yet. In this paper at first a good equilibrium circuit designed for PMT, and it was used for investigating about capacitors and resistors in much manner. Results show that decoupling capacitors have great effect on PMT output pulses. In this research, it was tried to investigate the effect of Capacitor’s value and places on PMT voltage divider in Neutron-Gamma discrimination capability. Therefore, the voltage divider circuit for R329-02 Hamamatsu PMT was made and Zero Cross method used for neutron-gamma discrimination. The neutron source was a 20Ci Am-Be. Anode and Dynode pulses and discrimination spectrum were saved. The results showed that the pulse height and discrimination quality change with the value and setting of capacitors

Ultra-capacitors in power conversion systems analysis, modeling and design in theory and practice

CERN Document Server

Grbovic, Petar J

2014-01-01

Divided into five parts, this book is focused on ultra-capacitors and their applications in power conversion systems. It discusses ultra-capacitor analysis, modelling and module design from a macroscopic (application) perspective. It also describes power conversion applications, interface dc-dc converter design and entire conversion system design. Part One covers the background of energy storage technologies, with particular attention on state-of-the-art ultra-capacitor energy storage technologies. In Chapter four of this part, power conversion systems with integrated energy storage is discus

Study on oxidization of Ru and its application as electrode of PZT capacitor for FeRAM

International Nuclear Information System (INIS)

Jia Ze; Ren Tianling; Liu Tianzhi; Hu Hong; Zhang Zhigang; Xie Dan; Liu Litian

2007-01-01

Oxidization for Ru through anneal with plenteous oxygen atmosphere and its application as the top electrode of sol-gel PZT capacitor are investigated in this study. PZT capacitor with RuO 2 or oxygen-doped Ru as top electrode can be obtained from Ru/PZT/Pt capacitor through slow-rate anneal at 650 deg. C for 20 min in cannulation furnace. It has larger remanent polarization, better rectangle shape, better fatigue properties and lower leakage current than the other capacitors with PZT film prepared by the same process and different top electrodes in this study. Plenteous oxygen atmosphere and 650 deg. C in cannulation furnace are important conditions for the oxidation of Ru and renewed crystallization of PZT in this capacitor. Plenteous oxygen at interface can compensate the oxygen vacancies at PZT/electrode interface, which results in the above good characteristics

The Split-Brain Phenomenon Revisited: A Single Conscious Agent with Split Perception.

Science.gov (United States)

Pinto, Yair; de Haan, Edward H F; Lamme, Victor A F

2017-11-01

The split-brain phenomenon is caused by the surgical severing of the corpus callosum, the main route of communication between the cerebral hemispheres. The classical view of this syndrome asserts that conscious unity is abolished. The left hemisphere consciously experiences and functions independently of the right hemisphere. This view is a cornerstone of current consciousness research. In this review, we first discuss the evidence for the classical view. We then propose an alternative, the 'conscious unity, split perception' model. This model asserts that a split brain produces one conscious agent who experiences two parallel, unintegrated streams of information. In addition to changing our view of the split-brain phenomenon, this new model also poses a serious challenge for current dominant theories of consciousness. Copyright © 2017 Elsevier Ltd. All rights reserved.

Graphene oxide-based flexible metal–insulator–metal capacitors

International Nuclear Information System (INIS)

Bag, A; Hota, M K; Mallik, S; Maiti, C K

2013-01-01

This work explores the fabrication of graphene oxide (GO)-based metal–insulator–metal (MIM) capacitors on flexible polyethylene terephthalate (PET) substrates. Electrical properties are studied in detail. A high capacitance density of ∼4 fF µm −2 measured at 1 MHz and permittivity of ∼6 have been obtained. A low voltage coefficient of capacitance, VCC-α, and a low dielectric loss tangent indicate the potential of GO-based MIM capacitors for RF applications. The constant voltage stressing study has shown a high reliability against degradation up to a projected period of 10 years. Degradation in capacitance of the devices on flexible substrates has been studied by bending radius down to 1 cm even up to 6000 times of repeated bending. (paper)

Identifying dielectric and resistive electrode losses in high-density capacitors at radio frequencies

NARCIS (Netherlands)

Tiggelman, M.P.J.; Reimann, K.; Liu, J.; Klee, M.; Keur, W.; Mauczock, R.; Schmitz, Jurriaan; Hueting, Raymond Josephus Engelbart

2008-01-01

A regression-based technique is presented which distinguishes the dielectric loss from the resistive loss of high density planar capacitors in a very wide bandwidth of 0.1–8 GHz. Moreover, the procedure yields useful results if the capacitor deviates from a lumped element model and indicates when

The impact of switching capacitor banks with very high inrush current on switchgear

NARCIS (Netherlands)

Smeets, R.P.P.; Wiggers, R.; Bannink, H.; Kuivenhoven, S.; Chakraborty, S.; Sandolache, G.

2012-01-01

Capacitor banks are installed in an increasing number in order to control power quality issues in the transmission and distribution networks. Due to load fluctuation, switching of capacitor banks is normally a daily operation. Although the current to be switched (e.g. the normal load current) is far

Triadic split-merge sampler

Science.gov (United States)

van Rossum, Anne C.; Lin, Hai Xiang; Dubbeldam, Johan; van der Herik, H. Jaap

2018-04-01

In machine vision typical heuristic methods to extract parameterized objects out of raw data points are the Hough transform and RANSAC. Bayesian models carry the promise to optimally extract such parameterized objects given a correct definition of the model and the type of noise at hand. A category of solvers for Bayesian models are Markov chain Monte Carlo methods. Naive implementations of MCMC methods suffer from slow convergence in machine vision due to the complexity of the parameter space. Towards this blocked Gibbs and split-merge samplers have been developed that assign multiple data points to clusters at once. In this paper we introduce a new split-merge sampler, the triadic split-merge sampler, that perform steps between two and three randomly chosen clusters. This has two advantages. First, it reduces the asymmetry between the split and merge steps. Second, it is able to propose a new cluster that is composed out of data points from two different clusters. Both advantages speed up convergence which we demonstrate on a line extraction problem. We show that the triadic split-merge sampler outperforms the conventional split-merge sampler. Although this new MCMC sampler is demonstrated in this machine vision context, its application extend to the very general domain of statistical inference.

Effect of electronic spatial extents (ESE) of ions on overpotential of lithium ion capacitors

International Nuclear Information System (INIS)

Xu, Fan; Lee, Chung ho; Koo, Chong Min; Jung, Cheolsoo

2014-01-01

Highlights: •Electronic spatial extent (ESE) of ion characterizes its electron density volume. •The ESE of ion proposes to assess overpotential of nanoporous capacitor. •Anion with low ESE shows low overpotential of the capacitor. •The ESE is more realistic to assess overpotential than conductivity or ion size. -- Abstract: The electronic spatial extent (ESE) of ions was defined as a major concept for assessing the cause of overpotential in the charging and discharging processes of a nanoporous activated carbon (AC) electrode. The performance degradation of AC/Li half-cells was caused by the overpotential, which was in discord with the electrolyte conductivity and ion size. Compared to the overpotential with the salt concentration, the AC/Li half-cell with a high concentration had a smaller overpotential, and its discharge patterns were similar to the curves obtained from the half-cells with a smaller ESE of BF 4 − ion. The ESE is a more realistic solution for determining the overpotential of the nanoporous capacitor, such as supercapacitor and Li ion capacitor, because its capacity is dependent on the electron density at the electric double layer of the capacitor electrode

Performance of AC/graphite capacitors at high weight ratios of AC/graphite

Energy Technology Data Exchange (ETDEWEB)

Wang, Hongyu [IM and T Ltd., Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Yoshio, Masaki [Advanced Research Center, Department of Applied Chemistry, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

2008-03-01

The effect of negative to positive electrode materials' weight ratio on the electrochemical performance of both activated carbon (AC)/AC and AC/graphite capacitors has been investigated, especially in the terms of capacity and cycle-ability. The limited capacity charge mode has been proposed to improve the cycle performance of AC/graphite capacitors at high weight ratios of AC/graphite. (author)

Chemical modification of graphene aerogels for electrochemical capacitor applications.

Science.gov (United States)

Hong, Jin-Yong; Wie, Jeong Jae; Xu, Yu; Park, Ho Seok

2015-12-14

Graphene aerogel is a relatively new type of aerogel that is ideal for energy storage applications because of its large surface area, high electrical conductivity and good chemical stability. Also, three dimensional interconnected macropores offer many advantages such as low density, fast ion and mass transfer, and easy access to storage sites. Such features allow graphene aerogels to be intensively applied for electrochemical capacitor applications. Despite the growing interest in graphene aerogel-based electrochemical capacitors, however, the graphene aerogels still suffer from their low capacitive performances and high fragility. Both relatively low capacitance and brittleness of physically crosslinked graphene aerogels remain a critical challenge. Until now, a number of alternative attempts have been devoted to overcome these shortcomings. In this perspective, we summarize the recent research progress towards the development of advanced graphene aerogel-based electrochemical capacitors according to the different approaches (e.g. porosity, composition and structure controls). Then, the recently proposed chemical strategies to improve the capacitive performances and mechanical durability of graphene aerogels for practical applications are highlighted. Finally, the current challenges and perspectives in this emerging material are also discussed.

Electric converters of electromagnetic strike machine with capacitor supply

Science.gov (United States)

Usanov, K. M.; Volgin, A. V.; Kargin, V. A.; Moiseev, A. P.; Chetverikov, E. A.

2018-03-01

The application of pulse linear electromagnetic engines in small power strike machines (energy impact is 0.01...1.0 kJ), where the characteristic mode of rare beats (pulse seismic vibrator, the arch crash device bins bulk materials), is quite effective. At the same time, the technical and economic performance of such machines is largely determined by the ability of the power source to provide a large instantaneous power of the supply pulses in the winding of the linear electromagnetic motor. The use of intermediate energy storage devices in power systems of rare-shock LEME makes it possible to obtain easily large instantaneous powers, forced energy conversion, and increase the performance of the machine. A capacitor power supply of a pulsed source of seismic waves is proposed for the exploration of shallow depths. The sections of the capacitor storage (CS) are connected to the winding of the linear electromagnetic motor by thyristor dischargers, the sequence of activation of which is determined by the control device. The charge of the capacitors to the required voltage is made directly from the battery source, or through the converter from a battery source with a smaller number of batteries.

Voltage ripple compensation for grid connected electrolyser power supply using small DC link capacitor

DEFF Research Database (Denmark)

Török, Lajos; Mathe, Laszlo; Munk-Nielsen, Stig

2014-01-01

The purpose of this work was to investigate a three-phase-grid connected power supply using small DC link capacitor for electrolyser application. The hydrogen generation system requires low voltage and high current power supply. Thus the structure of the 3-phase power supply is defined as follows......: a three phase rectification, a small DC-link capacitor and a phase-shifted full-bridge converter with current doubler rectification. Design constraints and control problems are investigated. The advantages and problems caused by the use of small DC link capacitor are presented. The control of the system...

Effects of Radiation on Capacitor Dielectrics

Science.gov (United States)

Bouquet, F. L.; Somoano, R. B.; Frickland, P. O.

1987-01-01

Data gathered on key design parameters. Report discusses study of electrical and mechanical properties of irradiated polymer dielectric materials. Data compiled for use by designers of high-energy-density capacitors that operate in presence of ionizing radiation. Study focused on polycarbonates, polyetheretherketones, polymethylpentenes, polyimides (including polyetherimide), polyolefins, polysulfones (including polyethersulfone and polyphenylsulfone), and polyvinylidene fluorides.

The possibility of giant dielectric materials for multilayer ceramic capacitors.

Science.gov (United States)

Ishii, Tatsuya; Endo, Makoto; Masuda, Kenichiro; Ishida, Keisuke

2013-02-11

There have been numerous reports on discovery of giant dielectric permittivity materials called internal barrier layer capacitor in the recent years. We took particular note of one of such materials, i.e., BaTiO 3 with SiO 2 coating. It shows expressions of giant electric permittivity when processed by spark plasma sintering. So we evaluated various electrical characteristics of this material to find out whether it is applicable to multilayer ceramic capacitors. Our evaluation revealed that the isolated surface structure is the sole cause of expressions of giant dielectric permittivity.

Evaluation of high temperature capacitor dielectrics

Science.gov (United States)

Hammoud, Ahmad N.; Myers, Ira T.

1992-01-01

Experiments were carried out to evaluate four candidate materials for high temperature capacitor dielectric applications. The materials investigated were polybenzimidazole polymer and three aramid papers: Voltex 450, Nomex 410, and Nomex M 418, an aramid paper containing 50 percent mica. The samples were heat treated for six hours at 60 C and the direct current and 60 Hz alternating current breakdown voltages of both dry and impregnated samples were obtained in a temperature range of 20 to 250 C. The samples were also characterized in terms of their dielectric constant, dielectric loss, and conductivity over this temperature range with an electrical stress of 60 Hz, 50 V/mil present. Additional measurements are underway to determine the volume resistivity, thermal shrinkage, and weight loss of the materials. Preliminary data indicate that the heat treatment of the films slightly improves the dielectric properties with no influence on their breakdown behavior. Impregnation of the samples leads to significant increases in both alternating and direct current breakdown strength. The results are discussed and conclusions made concerning their suitability as high temperature capacitor dielectrics.

A fast 30 kV 5 kHz repetition rate resonant capacitor charger

NARCIS (Netherlands)

Beckers, F.J.C.M.; Huiskamp, T.; van Heesch, E.J.M.; Pemen, A.J.M.

2016-01-01

A novel circuit topology of a fast 30 kV resonant capacitor charger is presented in this paper. The charger is designed for high repetition rate spark gap based pulsed power modulators. A spark gap can fire spontaneously (pre-firing) during charging of a capacitor bank due to poor dielectric

Feasibility Study to Evaluate Candidate Materials of Nanofilled Block Copolymers for Use in Ultra High Density Pulsed Power Capacitors

Science.gov (United States)

2015-10-26

capacitor films showing the first-ever application of self-assembling BCPs as the nanostructured dielectric media in electrostatic capacitors . Using... dielectric media in electrostatic capacitors . Using controlled ordering of lamellae- forming BCPs via our cold zone annealing soft-shear (CZA-SS...fast energy storage and discharge capabilities. However, the energy storage density of these capacitors is limited by the dielectric properties of

The Impact of Grid Unbalances on the Reliability of DC-link Capacitors in a Motor Drive

DEFF Research Database (Denmark)

Wang, Huai; Davari, Pooya; Kumar, Dinesh

2017-01-01

DC-link capacitor is one of the reliability-critical components in motor drive applications, which contributes to a considerable cost, size and failure. Its reliability performance depends on both inherent physical strength and external loading. The grid unbalances could alter the electro......-thermal stresses of key components in a motor drive. Therefore, this digest investigates the impact of grid voltage amplitude and phase unbalances on the lifetime of DC-link capacitors used in a standard three-phase motor drive. The theoretical stress models and experimental measurements of the capacitor voltages...... and ripple currents are presented. The relationship between the DC-link capacitor lifetime and the level of unbalances and loads are discussed based on a 7.5 kW motor drive system. The results serve as a guideline to size the DC-link capacitors to be robust enough at the presence of grid unbalance conditions....

The permanent process

DEFF Research Database (Denmark)

Møller, Jesper; McCullagh, Peter

We extend the boson process first to a large class of Cox processes and second an even larger class of infinitely divisible point processes. Density and moment results are studied in detail. These results are obtained in closed form as weighted permanents, so the extension is called a permanent...... process. Temporal extensions and a particularly tractable case of the permanent process are also studied. Extensions of the ferminon process along similar lines, leading to so-called determinant processes, are discussed at the end. While the permanent process is attractive, the determinant process...

Tube-Super Dielectric Materials: Electrostatic Capacitors with Energy Density Greater than 200 J·cm-3.

Science.gov (United States)

Cortes, Francisco Javier Quintero; Phillips, Jonathan

2015-09-17

The construction and performance of a second generation of super dielectric material based electrostatic capacitors (EC), with energy density greater than 200 J·cm - ³, which rival the best reported energy density of electric double layer capacitors (EDLC), also known as supercapacitors, are reported. The first generation super dielectric materials (SDM) are multi-material mixtures with dielectric constants greater than 1.0 × 10⁵, composed of a porous, electrically insulating powder filled with a polarizable, ion-containing liquid. Second-generation SDMs (TSDM), introduced here, are anodic titania nanotube arrays filled with concentrated aqueous salt solutions. Capacitors using TiO₂ based TSDM were found to have dielectric constants at ~0 Hz greater than 10⁷ in all cases, a maximum operating voltage of greater than 2 volts and remarkable energy density that surpasses the highest previously reported for EC capacitors by approximately one order of magnitude. A simple model based on the classic ponderable media model was shown to be largely consistent with data from nine EC type capacitors employing TSDM.

Tube-Super Dielectric Materials: Electrostatic Capacitors with Energy Density Greater than 200 J·cm−3

Directory of Open Access Journals (Sweden)

Francisco Javier Quintero Cortes

2015-09-01

Full Text Available The construction and performance of a second generation of super dielectric material based electrostatic capacitors (EC, with energy density greater than 200 J·cm−3, which rival the best reported energy density of electric double layer capacitors (EDLC, also known as supercapacitors, are reported. The first generation super dielectric materials (SDM are multi-material mixtures with dielectric constants greater than 1.0 × 105, composed of a porous, electrically insulating powder filled with a polarizable, ion-containing liquid. Second-generation SDMs (TSDM, introduced here, are anodic titania nanotube arrays filled with concentrated aqueous salt solutions. Capacitors using TiO2 based TSDM were found to have dielectric constants at ~0 Hz greater than 107 in all cases, a maximum operating voltage of greater than 2 volts and remarkable energy density that surpasses the highest previously reported for EC capacitors by approximately one order of magnitude. A simple model based on the classic ponderable media model was shown to be largely consistent with data from nine EC type capacitors employing TSDM.

DETECTION OF FLUX EMERGENCE, SPLITTING, MERGING, AND CANCELLATION OF NETWORK FIELD. I. SPLITTING AND MERGING

Energy Technology Data Exchange (ETDEWEB)

Iida, Y.; Yokoyama, T. [Department of Earth and Planetary Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Hagenaar, H. J. [Lockheed Martin Advanced Technology Center, Org. ADBS, Building 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States)

2012-06-20

Frequencies of magnetic patch processes on the supergranule boundary, namely, flux emergence, splitting, merging, and cancellation, are investigated through automatic detection. We use a set of line-of-sight magnetograms taken by the Solar Optical Telescope (SOT) on board the Hinode satellite. We found 1636 positive patches and 1637 negative patches in the data set, whose time duration is 3.5 hr and field of view is 112'' Multiplication-Sign 112''. The total numbers of magnetic processes are as follows: 493 positive and 482 negative splittings, 536 positive and 535 negative mergings, 86 cancellations, and 3 emergences. The total numbers of emergence and cancellation are significantly smaller than those of splitting and merging. Further, the frequency dependence of the merging and splitting processes on the flux content are investigated. Merging has a weak dependence on the flux content with a power-law index of only 0.28. The timescale for splitting is found to be independent of the parent flux content before splitting, which corresponds to {approx}33 minutes. It is also found that patches split into any flux contents with the same probability. This splitting has a power-law distribution of the flux content with an index of -2 as a time-independent solution. These results support that the frequency distribution of the flux content in the analyzed flux range is rapidly maintained by merging and splitting, namely, surface processes. We suggest a model for frequency distributions of cancellation and emergence based on this idea.

Li-Ion, Ultra-capacitor Based Hybrid Energy Module

National Research Council Canada - National Science Library

Daboussi, Zaher; Paryani, Anil; Khalil, Gus; Catherino, Henry; Gargies, Sonya

2007-01-01

Ultra-capacitors in multi kilo-farad ranges are now starting to be considered as alternatives or complimentary to batteries for products ranging from toys to hybrid vehicles as well as for space applications...

The Most Energy Efficient Way to Charge the Capacitor in an RC Circuit

Science.gov (United States)

Wang, Dake

2017-01-01

The voltage waveform that minimizes the energy loss in the resistance when charging the capacitor in a resistor-capacitor circuit is investigated using the calculus of variation. A linear voltage ramp gives the best efficiency, which means a constant current source should be used for charging. Comparison between constant current source and…

Measurements of fuse and resistor characteristics for multi-megajoule capacitor bank application

International Nuclear Information System (INIS)

McDonald, K.F.; Smith, T.; Golden, J.; Conley, B.

1986-01-01

Experimental tests have been conducted on commercially available fuses and resistors under fast high voltage pulsed (10 μsec) conditions to determine their ability to protect capacitor bank components during faults. NRL's Modified Betatron Accelerator uses two multi-megajoule capacitor banks to power the toroidal and betatron magnetic field coils. The expensive high energy density capacitors in these banks must be protected from excessive peak current, voltage reversal, or charging beyond their electrical ratings in the occurrence of a fault. Adequate protection can be obtained with fuses and resistors in series with each parallel connected capacitor. The fuses must open reliably and hold off high voltage D.C. (10 - 20 kV), and the resistors must conduct high current and di/dt without failing from energy deposition or magnetic forces. The performance of the commercial fuses is well documented at low AC frequencies and currents (60 Hz/100 A) but data was not previously available for the fast high current pulsed conditions that prevail under actual fault conditions. A 20 kV 200 kJ, low inductance capacitor bank and ignitron switch were used to conduct the experiments. Peak currents in the fuses were approximately 170 kA at t - 6.5 μs. The final fuse hold-off voltage exceeded 8 kV. Currents in the resistors ranged from - 20 - 40 kA per resistor. The experimental results have been compared to the manufacturers data from minimum melt and maximum let-through and to exploding bridge wire computer models

A Comparison of Electrolytic Capacitors and Supercapacitors for Piezo-Based Energy Harvesting

Science.gov (United States)

2013-07-01

A Comparison of Electrolytic Capacitors and Supercapacitors for Piezo-Based Energy Harvesting by Matthew H. Ervin, Carlos M. Pereira, John R...Capacitors and Supercapacitors for Piezo-Based Energy Harvesting Matthew H. Ervin Sensors and Electronic Devices Directorate, ARL Carlos M. Pereira... Supercapacitors for Piezo-Based Energy Harvesting 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Matthew H

Splitting: The Development of a Measure.

Science.gov (United States)

Gerson, Mary-Joan

1984-01-01

Described the development of a scale that measures splitting as a psychological structure. The construct validity of the splitting scale is suggested by the positive relationship between splitting scores and a diagnostic measure of the narcissistic personality disorder, as well as a negative relationship between splitting scores and levels of…

Bad splits in bilateral sagittal split osteotomy: systematic review and meta-analysis of reported risk factors.

Science.gov (United States)

Steenen, S A; van Wijk, A J; Becking, A G

2016-08-01

An unfavourable and unanticipated pattern of the bilateral sagittal split osteotomy (BSSO) is generally referred to as a 'bad split'. Patient factors predictive of a bad split reported in the literature are controversial. Suggested risk factors are reviewed in this article. A systematic review was undertaken, yielding a total of 30 studies published between 1971 and 2015 reporting the incidence of bad split and patient age, and/or surgical technique employed, and/or the presence of third molars. These included 22 retrospective cohort studies, six prospective cohort studies, one matched-pair analysis, and one case series. Spearman's rank correlation showed a statistically significant but weak correlation between increasing average age and increasing occurrence of bad splits in 18 studies (ρ=0.229; Pbad split among the different splitting techniques. A meta-analysis pooling the effect sizes of seven cohort studies showed no significant difference in the incidence of bad split between cohorts of patients with third molars present and concomitantly removed during surgery, and patients in whom third molars were removed at least 6 months preoperatively (odds ratio 1.16, 95% confidence interval 0.73-1.85, Z=0.64, P=0.52). In summary, there is no robust evidence to date to show that any risk factor influences the incidence of bad split. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

A Steady-State Analysis Method for Modular Multilevel Converters Connected to Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems

Directory of Open Access Journals (Sweden)

Zhijie Liu

2018-02-01

Full Text Available Modular multilevel converters (MMCs have shown great potential in the area of multi-megawatt wind energy conversion system (WECS based on permanent magnet synchronous generators (PMSGs. However, the studies in this area are few, and most of them refer to the MMC used in high-voltage direct current (HVDC systems, and hence the characteristics of the PMSG are not considered. This paper proposes a steady-state analysis method for MMCs connected to a PMSG-based WECS. In the proposed method, only the wind speed (operating condition is required as input, and all the electrical quantities in the MMC, including the amplitudes, phase angles and their harmonics, can be calculated step by step. The analysis method is built on the proposed d-q frame mathematical model. Interactions of electrical quantities between the MMC and PMSG are comprehensively considered. Moreover, a new way to calculate the average switching functions are adopted in order to improve the accuracy of the analysis method. Applications of the proposed method are also presented, which includes the characteristic analysis of capacitor voltage ripples and the capacitor sizing. Finally, the accuracy of the method and the correctness of the analysis are verified by simulations and experiments.

Incorporation of distributed generation and shunt capacitor in radial distribution system for techno-economic benefits

Directory of Open Access Journals (Sweden)

Mukul Dixit

2017-04-01

The various costs such as purchase active power from grid, DG installation, capacitor installation, DG Operation and Maintenance (O&M are evaluated at two different load scenarios. In addition to that, technical and economical analyses are examined for various combinations of DGs and shunt capacitors. The proposed methodology is successfully demonstrated on 33-bus and 85-bus radial networks and the obtained numerical outcomes validate the suitability, importance and effectiveness to identify locations as well as sizes of DGs and shunt capacitors.

Protective systems and its protective switching elements on local failures of large slow-capacitor bank system

International Nuclear Information System (INIS)

Hasegawa, Mitsuo; Inoue, Kunikazu; Ueno, Isao.

1994-01-01

In various applications of pulsed power technologies, large capacitor bank systems are used to feed high current impulse to different experimental devices. The accidental electric breakdown in one of the capacitors in a parallel connection of the large bank may result in serious damages such as mechanical explosion and oil effusion or fire. In most fast banks, each unit capacitor has an output gap switch, which is expected to decouple the capacitors one another. However, no such special element is adopted usually in the slow bank system, partly because of the economical consideration. We have developed a novel and inexpensive protective element for these relatively slow capacitor banks, utilizing a concept of the enclosed type of the fast breakers. The principle of the operation of the protection elements is verified by a simulation experiment. Their practical effectiveness is also successfully demonstrated in the application to the system of the pulsed high magnetic field generator. (author)

High energy, low inductance, high current fiberglass energy storage capacitor for the Atlas Machine Marx modules

CERN Document Server

Cooper, R A; Ennis, J B; Cochrane, J C; Reass, W A; Parsons, W M

1999-01-01

The Los Alamos National Laboratory's Atlas Marx design team envisioned a double ended plastic case 60 kV, 15 nH, 650 kA, energy storage capacitor. A design specification was established and submitted to various vendors. Maxwell Energy Products drew from its development of large fiberglass case, high voltage, low inductance "FASTCAP" capacitors manufactured for Maxwell Technologies' ACE II, ACE III and ACE IV machines. This paper discusses the LANL specification and Maxwell Energy Products' successful design, Model No. 39232, 34.1 mu F, 60 kV, 13*29*27", the only capacitor qualified by LANL for the 23 Mega Joule Atlas application. Maxwell's past experience in this type of capacitor is covered. The performance data is reviewed and the life test data compared to the original calculated design life. Challenges included Maxwell's "keep it simple " design goal which was maintained to minimize the effort required to create and manufacture a nearly 600 pound capacitor. (1 refs).

Optimal Value of Series Capacitors for Uniform Field Distribution in Transmission Line MRI Coils

DEFF Research Database (Denmark)

Zhurbenko, Vitaliy

2016-01-01

Transmission lines are often used as coils in high field magnetic resonance imaging (MRI). Due to the distributed nature of transmission lines, coils based on them produce inhomogeneous field. This work investigates application of series capacitors to improve field homogeneity along the coil....... The equations for optimal values of evenly distributed capacitors are derived and expressed in terms of the implemented transmission line parameters.The achieved magnetic field homogeneity is estimated under quasistatic approximation and compared to the regular transmission line resonator. Finally, a more...... practical case of a microstrip line coil with two series capacitors is considered....

Design of Neutral-Point Voltage Controller of a Three-level NPC Inverter with Small DC-Link Capacitors

DEFF Research Database (Denmark)

Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, S.

2013-01-01

A Neutral-Point-Clamped (NPC) three-level inverter with small dc-link capacitors is presented in this paper. The inverter requires zero average neutral-point current for stable neutral-point voltage. The small dc-link capacitors may not maintain capacitor voltage balance, even with zero neutral......-point voltage control on the basis of the continuous model. The design method for optimum performance is discussed. The implementation of the proposed modulation strategy and the controller is very simple. The controller is implemented in a 7.5 kW induction machine based drive with only 14 ìF dc-link capacitors...

Joint NetWork Reconfiguration and Capacitor Placement by Bactrial Foraging Algorithm

Directory of Open Access Journals (Sweden)

Mohammad Ali Mohammadnia

2011-01-01

Full Text Available Power system engineers are forced to place more emphasis on reducing losses at the distribution level. From an economic perspective, Joint network reconfiguration and capacitor placement is one of the best ways to save energy. Application of heuristic technique is unavoidable, because of expansion of distribution networks and becoming more complex connections in these grids. In view of this, for the first this paper investigates the ability of Bacterial Foraging Algorithm (BFA for Joint network reconfiguration and capacitor placement.

Graphene hydrogels deposited in nickel foams for high-rate electrochemical capacitors.

Science.gov (United States)

Chen, Ji; Sheng, Kaixuan; Luo, Peihui; Li, Chun; Shi, Gaoquan

2012-08-28

Graphene hydrogel/nickel foam composite electrodes for high-rate electrochemical capacitors are produced by reduction of an aqueous dispersion of graphene oxide in a nickel foam (upper half of figure). The micropores of the hydrogel are exposed to the electrolyte so that ions can enter and form electrochemical double-layers. The nickel framework shortens the distances of charge transfer. Therefore, the electrochemical capacitor exhibits highrate performance (see plots). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Accelerated Aging Experiments for Capacitor Health Monitoring and Prognostics

Data.gov (United States)

National Aeronautics and Space Administration — This paper discusses experimental setups for health monitoring and prognostics of electrolytic capacitors under nominal operation and accelerated aging conditions....

Split Malcev algebras

Indian Academy of Sciences (India)

project of the Spanish Ministerio de Educación y Ciencia MTM2007-60333. References. [1] Calderón A J, On split Lie algebras with symmetric root systems, Proc. Indian. Acad. Sci (Math. Sci.) 118(2008) 351–356. [2] Calderón A J, On split Lie triple systems, Proc. Indian. Acad. Sci (Math. Sci.) 119(2009). 165–177.

A 100 MS/s 9 bit 0.43 mW SAR ADC with custom capacitor array

Science.gov (United States)

Jingjing, Wang; Zemin, Feng; Rongjin, Xu; Chixiao, Chen; Fan, Ye; Jun, Xu; Junyan, Ren

2016-05-01

A low power 9 bit 100 MS/s successive approximation register analog-to-digital converter (SAR ADC) with custom capacitor array is presented. A brand-new 3-D MOM unit capacitor is used as the basic capacitor cell of this capacitor array. The unit capacitor has a capacitance of 1 fF. Besides, the advanced capacitor array structure and switch mode decrease the power consumption a lot. To verify the effectiveness of this low power design, the 9 bit 100 MS/s SAR ADC is implemented in TSMC IP9M 65 nm LP CMOS technology. The measurement results demonstrate that this design achieves an effective number of bits (ENOB) of 7.4 bit, a signal-to-noise plus distortion ratio (SNDR) of 46.40 dB and a spurious-free dynamic range (SFDR) of 62.31 dB at 100 MS/s with 1 MHz input. The SAR ADC core occupies an area of 0.030 mm2 and consumes 0.43 mW under a supply voltage of 1.2 V. The figure of merit (FOM) of the SAR ADC achieves 23.75 fJ/conv. Project supported by the National High-Tech Research and Development Program of China (No. 2013AA014101).

Two-Loop Splitting Amplitudes

International Nuclear Information System (INIS)

Bern, Z.

2004-01-01

Splitting amplitudes govern the behavior of scattering amplitudes at the momenta of external legs become collinear. In this talk we outline the calculation of two-loop splitting amplitudes via the unitarity sewing method. This method retains the simple factorization properties of light-cone gauge, but avoids the need for prescriptions such as the principal value or Mandelstam-Leibbrandt ones. The encountered loop momentum integrals are then evaluated using integration-by-parts and Lorentz invariance identities. We outline a variety of applications for these splitting amplitudes

Two-loop splitting amplitudes

International Nuclear Information System (INIS)

Bern, Z.; Dixon, L.J.; Kosower, D.A.

2004-01-01

Splitting amplitudes govern the behavior of scattering amplitudes at the momenta of external legs become collinear. In this talk we outline the calculation of two-loop splitting amplitudes via the unitarity sewing method. This method retains the simple factorization properties of light-cone gauge, but avoids the need for prescriptions such as the principal value or Mandelstam-Leibbrandt ones. The encountered loop momentum integrals are then evaluated using integration-by-parts and Lorentz invariance identities. We outline a variety of applications for these splitting amplitudes

Pulse Capacitors for Next Generation Linear Colliders. Final Report

International Nuclear Information System (INIS)

Hooker, M.W.

2000-01-01

During this Phase I SBIR research program, Nanomaterials Research Corporation (NRC) successfully demonstrated high-voltage multilayer capacitors produced from sub-100 nm ceramic powders. The devices produced by NRC exhibited properties that make them particularly useful for pulse power applications. These properties include (1) high capacitance (2) low loss (3) high breakdown voltage (4) high insulation resistance and (5) rapid discharge characteristics. Furthermore, the properties of the nanostructured capacitors were consistently found to exceed those of components that represent the state of the art within the industry. Encouraged by these results, NRC is planning to submit a Phase II proposal with the objective of securing seed capital to continue this development effort

Differential RF MEMS interwoven capacitor immune to residual stress warping

KAUST Repository

Elshurafa, Amro M.

2012-07-27

A RF MEMS capacitor with an interwoven structure is designed, fabricated in the PolyMUMPS process and tested in an effort to address fabrication challenges usually faced in MEMS processes. The interwoven structure was found to offer several advantages over the typical MEMS parallel-plate design including eliminating the warping caused by residual stress, eliminating the need for etching holes, suppressing stiction, reducing parasitics and providing differential capability. The quality factor of the proposed capacitor was higher than five throughout a 2–10 GHz range and the resonant frequency was in excess of 20 GHz.

Differential RF MEMS interwoven capacitor immune to residual stress warping

KAUST Repository

Elshurafa, Amro M.; Salama, Khaled N.

2012-01-01

A RF MEMS capacitor with an interwoven structure is designed, fabricated in the PolyMUMPS process and tested in an effort to address fabrication challenges usually faced in MEMS processes. The interwoven structure was found to offer several advantages over the typical MEMS parallel-plate design including eliminating the warping caused by residual stress, eliminating the need for etching holes, suppressing stiction, reducing parasitics and providing differential capability. The quality factor of the proposed capacitor was higher than five throughout a 2–10 GHz range and the resonant frequency was in excess of 20 GHz.

Electrical Properties of a Thin Anodized Capacitor Made of Y-Doped Al Alloy Film

Science.gov (United States)

Onozuka, Tomotake; Sasaki, Hayato; Mikuni, Naohiro; Shinkai, Satoko; Sasaki, Katsutaka; Yamane, Misao; Abe, Yoshio

2005-09-01

We have prepared an Al-Y anodized capacitor using sputter-deposited Al-Y alloy film with 5 at. % Y atoms, and evaluated the capacitor properties and the leakage current properties before and after heat treatment. In addition, the characterization of Al-Y anodized films was examined by X-ray diffraction, Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy analyses. As a result, it is revealed that the thermal stability of an Al-Y anodized capacitor is superior to that of a pure Al anodized capacitor because of its excellent passive nature, and the loss properties can be improved by increasing the heat treatment temperature in air because of the reduction of the equivalent series resistance. Furthermore, it is clarified that the cause of the short-circuited state observed at 550°C is the formation of a narrow capillary-like conduction path of metallic Al atoms as a result of the interdiffusion of Al.

Aging and failure mode of electrochemical double layer capacitors during accelerated constant load tests

Energy Technology Data Exchange (ETDEWEB)

Koetz, R.; Ruch, P.W.; Cericola, D. [General Energy Research Department, Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen (Switzerland)

2010-02-01

Electrochemical double layer capacitors of the BCAP0350 type (Maxwell Technologies) were tested under constant load conditions at different voltages and temperatures. The aging of the capacitors was monitored during the test in terms of capacitance, internal resistance and leakage current. Aging was significantly accelerated by elevated temperature or increased voltage. Only for extreme conditions at voltages of 3.5 V or temperatures above 70 C the capacitors failed due to internal pressure build-up. No other failure events such as open circuit or short circuit were detected. Impedance measurements after the tests showed increased high frequency resistance, an increased distributed resistance and most likely an increase in contact resistance between electrode and current collector together with a loss of capacitance. Capacitors aged at elevated voltages (3.3 V) exhibited a tilting of the low frequency component, which implies an increase in the heterogeneity of the electrode surface. This feature was not observed upon aging at elevated temperatures (70 C). (author)

The Significance of Breakdown Voltages for Quality Assurance of Low-Voltage BME Ceramic Capacitors

Science.gov (United States)

Teverovsky, Alexander A.

2014-01-01

Application of thin dielectric, base metal electrode (BME) ceramic capacitors for high-reliability applications requires development of testing procedures that can assure high quality and reliability of the parts. In this work, distributions of breakdown voltages (VBR) in variety of low-voltage BME multilayer ceramic capacitors (MLCCs) have been measured and analyzed. It has been shown that analysis of the distributions can indicate the proportion of defective parts in the lot and significance of the defects. Variations of the distributions after solder dip testing allow for an assessment of the robustness of capacitors to soldering-related stresses. The drawbacks of the existing screening and qualification methods to reveal defects in high-value, low-voltage MLCCs and the importance of VBR measurements are discussed. Analysis has shown that due to a larger concentration of oxygen vacancies, defect-related degradation of the insulation resistance (IR) and failures are more likely in BME compared to the precious metal electrode (PME) capacitors.

Concentric Split Flow Filter

Science.gov (United States)

Stapleton, Thomas J. (Inventor)

2015-01-01

A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

Tunable fractional-order capacitor using layered ferroelectric polymers

KAUST Repository

Agambayev, Agamyrat; Patole, Shashikant P.; Bagci, Hakan; Salama, Khaled N.

2017-01-01

Pairs of various Polyvinylidene fluoride P(VDF)-based polymers are used for fabricating bilayer fractional order capacitors (FOCs). The polymer layers are constructed using a simple drop casting approach. The resulting FOC has two advantages: It can

Mismatch-Shaped Pseudo-Passive Two-Capacitor DAC

DEFF Research Database (Denmark)

Steensgaard-Madsen, Jesper; Moon, Un-Ku; Temes, Gabor C.

1999-01-01

A simple mismatch-shaping scheme is proposed for a two-capacitor DAC. Unlike in other mismatch-shaping systems, the shaped error is generated by direct filtering of a well-defined bounded signal, which can be generated as white noise. The operation is closely related to a specific digital...

Aging Methodologies and Prognostic Health Management for Electrolytic Capacitors

Data.gov (United States)

National Aeronautics and Space Administration — Understanding the ageing mechanisms of electronic components critical avionics systems such as the GPS and INAV are of critical importance. Electrolytic capacitors...

Comparison of converter topologies for charging capacitors used in pulsed load applications

Science.gov (United States)

Nelms, R. M.; Schatz, J. E.; Pollard, Barry

1991-01-01

The authors present a qualitative comparison of different power converter topologies which may be utilized for charging capacitors in pulsed power applications requiring voltages greater than 1 kV. The operation of the converters in capacitor charging applications is described, and relevant advantages are presented. All of the converters except one may be classified in the high-frequency switching category. One of the benefits from high-frequency operation is a reduction in size and weight. The other converter discussed is a member of the command resonant changing category. The authors first describe a boost circuit which functions as a command resonant charging circuit and utilizes a single pulse of current to charge the capacitor. The discussion of high-frequency converters begins with the flyback and Ward converters. Then, the series, parallel, and series/parallel resonant converters are examined.

The Question of Decalage Between Object Permanence and Person Permanence

Science.gov (United States)

And Others; Jackson, Elaine

1978-01-01

Presents a study of decalage between object permanence and person permanence. Decalage was influenced by environmental as well as stimulus factors with infants tested between 6- and 81/4-months/of-age. (BD)

Essure Permanent Birth Control

Science.gov (United States)

... Prosthetics Essure Permanent Birth Control Essure Permanent Birth Control Share Tweet Linkedin Pin it More sharing options ... Print Essure is a a permanently implanted birth control device for women (female sterilization). Implantation of Essure ...

Some properties of castor oil affecting its performance as a capacitor impregnant and their significance to future impregnant research

International Nuclear Information System (INIS)

Boicourt, G.P.

1975-01-01

For a considerable time castor oil and polychlorinated biphenyl (PCB) have been the principal impregnants used in energy-storage capacitors. Castor oil has proven to be better than PCB for pulsed applications. PCB's have come under attack as an environmental hazard, while castor oil is a vegetable product and its supply and quality are subject to fluctuation. These two facts make the development of new impregnants desirable. The properties of PCB as a capacitor impregnant are well known. This paper first compares a number of properties of castor oil and PCB's. A comparison is made between the lives of castor oil capacitors and comparable PCB energy-storage capacitors. Some of the physical and chemical properties of castor oil which make it a good pulse capacitor impregnant are examined. These properties can be used as a guide for future research on new pulse capacitor impregnants

Quasi-resonant converter with divided resonant capacitor on primary and secondary side

OpenAIRE

Shiroyama, Hironobu; Matsuo, Hirofumi; Ishizuka, Yoichi

2009-01-01

This paper presents a quasi-resonant converter with divided resonant capacitor on primary and secondary side of the isolation transformer. A conventional quasi-resonant converter using flyback topology can realize soft switching with simple circuit. However, relatively large surge voltage is generated in the switching device. To suppress such surge voltage, resonant capacitor is divided on primary side and secondary side in the proposed converter. In case of prototype 95W converter, the volta...

Theory and experiment on charging and discharging a capacitor through a reverse-biased diode

Science.gov (United States)

Roy, Arijit; Mallick, Abhishek; Adhikari, Aparna; Guin, Priyanka; Chatterjee, Dibyendu

2018-06-01

The beauty of a diode lies in its voltage-dependent nonlinear resistance. The voltage on a charging and discharging capacitor through a reverse-biased diode is calculated from basic equations and is found to be in good agreement with experimental measurements. Instead of the exponential dependence of charging and discharging voltages with time for a resistor-capacitor circuit, a linear time dependence is found when the resistor is replaced by a reverse-biased diode. Thus, well controlled positive and negative ramp voltages are obtained from the charging and discharging diode-capacitor circuits. This experiment can readily be performed in an introductory physics and electronics laboratory.

Mismatch-shaping switching for two-capacitor DAC

DEFF Research Database (Denmark)

Steensgaard-Madsen, Jesper; Moon, U.; Temes, G.C.

1998-01-01

A mismatch-shaping scheme is proposed for a two-capacitor digital-to-analogue converter (DAC). It uses a delta-sigma loop for finding the optimal switching sequence for each input word. Simulations indicate that the scheme can be used for the realisation of DACs with 16 bit linearity and SNR...

A woven 2D touchpad sensor and a 1D slide sensor using soft capacitor fibers

International Nuclear Information System (INIS)

Gorgutsa, Stephan; Gu, Jian Feng; Skorobogatiy, Maksim

2012-01-01

Recently reported soft conductive-polymer-based capacitor fibers are used to build a fully woven 2D touchpad sensor and a 1D slide sensor. An individual capacitor fiber features a swiss-roll like structure having two dielectric and two conductive polymer films rolled together in a classic multilayer capacitor configuration. The soft fibers of sub-1 mm outer diameter are fabricated using a fiber drawing procedure from a macroscopic polymeric preform. An individual capacitor fiber is then demonstrated to act as a distributed sensor that allows the touch position to be determined by measuring the fiber’s AC response. In other words, a single fiber acts as a 1D slide sensor. Furthermore, we develop an electrical ladder network model to predict the distributed sensor properties of an individual fiber and show that this model describes the experimental measurements very well. Finally, a two-dimensional touchpad sensor is presented. The sensor is built by weaving a one-dimensional array of capacitor fibers in parallel to each other. The performance of the touchpad sensor is then characterized. (paper)

Towards A Model-based Prognostics Methodology for Electrolytic Capacitors: A Case Study Based on Electrical Overstress Accelerated Aging

Directory of Open Access Journals (Sweden)

Gautam Biswas

2012-12-01

Full Text Available This paper presents a model-driven methodology for predict- ing the remaining useful life of electrolytic capacitors. This methodology adopts a Kalman filter approach in conjunction with an empirical state-based degradation model to predict the degradation of capacitor parameters through the life of the capacitor. Electrolytic capacitors are important components of systems that range from power supplies on critical avion- ics equipment to power drivers for electro-mechanical actuators. These devices are known for their comparatively low reliability and given their critical role in the system, they are good candidates for component level prognostics and health management. Prognostics provides a way to assess remain- ing useful life of a capacitor based on its current state of health and its anticipated future usage and operational conditions. This paper proposes and empirical degradation model and discusses experimental results for an accelerated aging test performed on a set of identical capacitors subjected to electrical stress. The data forms the basis for developing the Kalman-filter based remaining life prediction algorithm.

Technological file for high energy storage power capacitors; Filiere technologique pour condensateurs de puissance a haute energie stockee

Energy Technology Data Exchange (ETDEWEB)

Michalczyk, P.

1996-03-28

The `Megajoule` project driven by the Commissariat a l`Energie atomique, needs the storage of an 450 MJ energy in a capacitor bank. Each unitary 78 kJ capacitor must be build in a safe technology. The life time of such a capacitor is materialized by a loss of capacitance for a given number of discharge and not by a short circuit which can damage a part of the installation. The answer to the specifications use the combination of two existing technologies. Impregnated film foil capacitors; dry metallized polymer film capacitors. The energy induced by internal dielectric failures is limited by self-healing; the right arrangement of influential parameters, which are the resistivity of the metallization and the drawing of the segmentation is necessary to achieve this phenomenon. Appropriate manufacturing process, space factor, impregnation and thermal treatments are required to optimise the dielectric strength of the capacitors. The first test results valid this developed technology and our conclusions suggest some ways to improve the volume energy. (author) 13 refs.

Split-illumination electron holography

Energy Technology Data Exchange (ETDEWEB)

Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Inada, Yoshikatsu [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Matsuda, Tsuyoshi [Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Taniyama, Akira [Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd., Amagasaki, Hyogo 660-0891 (Japan); Shindo, Daisuke [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Tonomura, Akira [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Okinawa Institute of Science and Technology, Graduate University, Onna-son, Okinawa 904-0495 (Japan); Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395 (Japan)

2012-07-23

We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

Split-illumination electron holography

International Nuclear Information System (INIS)

Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon; Inada, Yoshikatsu; Matsuda, Tsuyoshi; Taniyama, Akira; Shindo, Daisuke; Tonomura, Akira

2012-01-01

We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

Charging a Capacitor with a Photovoltaic Module

Science.gov (United States)

Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco; Navarro, Luis Barba

2017-01-01

Charging a capacitor with a photovoltaic module is an experiment which reveals a lot about the modules characteristics. It is customary to represent these characteristics with an equivalent circuit whose elements represent its physical parameters. The behavior of a photovoltaic module is very similar to that of a single cell but the electric…

Input-parallel output-parallel (IPOP) three-level (TL) DC/DC converters with minimized capacitor ripple currents

DEFF Research Database (Denmark)

Liu, Dong; Deng, Fujin; Zhang, Qi

2016-01-01

, the component current stresses in the proposed converters are reduced. More significantly, the combination of the proposed IPOP TL circuit structure and the interleaving control strategy can largely reduce the ripple currents on the two input capacitors not only by doubling the frequencies of the ripple...... currents on two input capacitors but also by counteracting part of these ripple currents according to the operation principle of the proposed converters. Therefore, the proposed IPOP TL DC/DC converters with the interleaving control strategy can improve the performances of the converters in increasing...... the lifetimes of the input capacitors and minimizing the sizes of the input capacitors. Finally, the simulation and experimental results are presented to verify the effectiveness and feasibility of the proposed converters combined with the interleaving control strategy....

Permanences GAG-EPA

CERN Document Server

GAC-EPA

2015-01-01

Le GAC organise chaque mois des permanences avec entretiens individuels. La prochaine permanence se tiendra le : Mardi 5 mai de 13 h 30 à 16 h 00 Salle de réunion de l’Association du personnel Les permanences suivantes auront lieu les mardis 2 juin, 1er septembre, 6 octobre, 3 novembre et 1er décembre 2015. Les permanences du Groupement des Anciens sont ouvertes aux bénéficiaires de la Caisse de pensions (y compris les conjoints survivants) et à tous ceux qui approchent de la retraite. Nous invitons vivement ces derniers à s’associer à notre groupement en se procurant, auprès de l’Association du personnel, les documents nécessaires.

Ni-BaTiO3-Based Base-Metal Electrode (BME) Ceramic Capacitors for Space Applications

Science.gov (United States)

Liu, Donhang; Fetter, Lula; Meinhold, Bruce

2015-01-01

A multi-layer ceramic capacitor (MLCC) is a high-temperature (1350C typical) co-fired ceramic monolithic that is composed of many layers of alternately stacked oxide-based dielectric and internal metal electrodes. To make the dielectric layers insulating and the metal electrode layers conducting, only highly oxidation-resistant precious metals, such as platinum, palladium, and silver, can be used for the co-firing of insulating MLCCs in a regular air atmosphere. MLCCs made with precious metals as internal electrodes and terminations are called precious-metal electrode (PME) capacitors. Currently, all military and space-level applications only address the use of PME capacitors.

RF MEMS Fractal Capacitors With High Self-Resonant Frequencies

KAUST Repository

Elshurafa, Amro M.; Emira, Ahmed; Radwan, Ahmed Gomaa; Salama, Khaled N.

2012-01-01

This letter demonstrates RF microelectromechanical systems (MEMS) fractal capacitors possessing the highest reported self-resonant frequencies (SRFs) in PolyMUMPS to date. Explicitly, measurement results show SRFs beyond 20 GHz. Furthermore, quality

Transparent and Flexible Capacitors with an Ultrathin Structure by Using Graphene as Bottom Electrodes

Directory of Open Access Journals (Sweden)

Tao Guo

2017-11-01

Full Text Available Ultrathin, transparent and flexible capacitors using graphene as the bottom electrodes were directly fabricated on polyethylene naphthalate (PEN substrates. ZrO2 dielectric films were deposited on the treated surface of graphene by atomic layer deposition (ALD. The deposition process did not introduce any detectible defects in the graphene, as indicated by Raman measurements, guaranteeing the electrical performances of the graphene electrodes. The Aluminum-doped zinc oxide (AZO films were prepared as the top electrodes using the ALD technique. The capacitors presented a high capacitance density (10.3 fF/μm2 at 10 kHz and a relatively low leakage current (5.3 × 10−6 A/cm2 at 1 V. Bending tests revealed that the capacitors were able to work normally at an outward bending radius of 10 mm without any deterioration of electrical properties. The capacitors exhibited an average optical transmittance of close to 70% at visible wavelengths. Thus, it opens the door to practical applications in transparent integrated circuits.

Switchable capacitor and method of making the same

NARCIS (Netherlands)

Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, Hendrikus; De Raedt, Walter

2006-01-01

A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom electrode, a dielectric layer deposited on at least part of said bottom electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to

Switchable capacitor and method of making the same

NARCIS (Netherlands)

Rottenberg, Xavier; Jansen, Henricus V.; Tilmans, Hendrikus; De Raedt, Walter

2003-01-01

A micro electromechanical switchable capacitor is disclosed, comprising a substrate, a bottom electrode, a dielectric layer deposited on at least part of said bottom electrode, a conductive floating electrode deposited on at least part of said dielectric layer, an armature positioned proximate to

Electrical effects in superfluid helium. I. thermoelectric effect in Einstein's capacitor

International Nuclear Information System (INIS)

Ledenyov, D.O.; Ledenyov, V.O.; Ledenyov, O.P.

2014-01-01

The Einstein's ideas about the thermodynamical fluctuational nature of some electrical phenomena and the difference of electrical potentials U in a capacitor at temperature T were proposed in 1906-1907. On base of these ideas we explain the experimental results, which were recently observed under the action of the second sound standing wave in the electrical capacitors which take placed in the superfluid Sup>4He and in the torsional mechanical resonator. The Einstein's approach, based on the interrelation of thermal, mechanical and electrical fluctuations, allows to obtain the quantitative results, coinciding with the experimental data for the correlations of the alternate low temperatures difference in second sound wave and alternate electric potentials difference between the capacitor plates in superfluid helium at as well as in the rotating mechanical oscillator

Cool covered sky-splitting spectrum-splitting FK

Energy Technology Data Exchange (ETDEWEB)

Mohedano, Rubén; Chaves, Julio; Falicoff, Waqidi; Hernandez, Maikel; Sorgato, Simone [LPI, Altadena, CA, USA and Madrid (Spain); Miñano, Juan C.; Benitez, Pablo [LPI, Altadena, CA, USA and Madrid, Spain and Universidad Politécnica de Madrid (UPM), Madrid (Spain); Buljan, Marina [Universidad Politécnica de Madrid (UPM), Madrid (Spain)

2014-09-26

Placing a plane mirror between the primary lens and the receiver in a Fresnel Köhler (FK) concentrator gives birth to a quite different CPV system where all the high-tech components sit on a common plane, that of the primary lens panels. The idea enables not only a thinner device (a half of the original) but also a low cost 1-step manufacturing process for the optics, automatic alignment of primary and secondary lenses, and cell/wiring protection. The concept is also compatible with two different techniques to increase the module efficiency: spectrum splitting between a 3J and a BPC Silicon cell for better usage of Direct Normal Irradiance DNI, and sky splitting to harvest the energy of the diffuse radiation and higher energy production throughout the year. Simple calculations forecast the module would convert 45% of the DNI into electricity.

Experimental determination of harmonic conditions amplification in a distribution network by capacitor bank switching

DEFF Research Database (Denmark)

Baloi, Alexandru; Kocewiak, Lukasz Hubert; Bak, Claus Leth

2012-01-01

The paper presents a study comprising laboratory measurements for the evaluation of the harmonic amplification due to capacitor bank switching. The mathematical model of the amplification factors of the current flowing on the circuit elements is presented. Theoretical aspects, regarding the total...... harmonic distortion (THD) of the capacitor current computed using the amplification factor, are originally presented. Nonlinear loads as six pulse rectifier and National Instruments measurement sensors together with LabView software were used on the laboratory set-up. The main instrument of the method...... is the harmonic impedance, “seen” in the bus of the capacitor bank switching. MatLab Simulink is used for the determination of the harmonic impedance....

ZONES OF STEADY CAPACITOR EXCITATION IN A MODE OF GENERATION OF TYPICAL ASYNCHRONOUS MACHINES

Directory of Open Access Journals (Sweden)

Postoronca Sv.

2009-12-01

Full Text Available In work some features of a mode of capacitor excitation of industrial asynchronous electric motors, and also generators made on their base which can be used in wind installations of low power are considered. Borders of zones of steady capacitor excitation of asynchronous electric motors in rated power of 0,25-22,0 kW and generators made on their base, and also character of influence of own losses and active capacity of loading of the equivalent circuit of the asynchronous machine resulted in parameters have been determined. Some recommendations after maintenance of stability of capacitor excitation of asynchronous machines for work in a mode of generation of electric energy are given.

Bad split during bilateral sagittal split osteotomy of the mandible with separators: a retrospective study of 427 patients.

Science.gov (United States)

Mensink, Gertjan; Verweij, Jop P; Frank, Michael D; Eelco Bergsma, J; Richard van Merkesteyn, J P

2013-09-01

An unfavourable fracture, known as a bad split, is a common operative complication in bilateral sagittal split osteotomy (BSSO). The reported incidence ranges from 0.5 to 5.5%/site. Since 1994 we have used sagittal splitters and separators instead of chisels for BSSO in our clinic in an attempt to prevent postoperative hypoaesthesia. Theoretically an increased percentage of bad splits could be expected with this technique. In this retrospective study we aimed to find out the incidence of bad splits associated with BSSO done with splitters and separators. We also assessed the risk factors for bad splits. The study group comprised 427 consecutive patients among whom the incidence of bad splits was 2.0%/site, which is well within the reported range. The only predictive factor for a bad split was the removal of third molars at the same time as BSSO. There was no significant association between bad splits and age, sex, class of occlusion, or the experience of the surgeon. We think that doing a BSSO with splitters and separators instead of chisels does not increase the risk of a bad split, and is therefore safe with predictable results. Copyright © 2012 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Magnetic Decoupling Design and Experimental Validation of a Radial-Radial Flux Compound-Structure Permanent-Magnet Synchronous Machine for HEVs

Directory of Open Access Journals (Sweden)

Zhiyi Song

2012-10-01

Full Text Available The radial-radial flux compound-structure permanent-magnet synchronous machine (CS-PMSM, integrated by two concentrically arranged permanent-magnet electric machines, is an electromagnetic power-splitting device for hybrid electric vehicles (HEVs. As the two electric machines share a rotor as structural and magnetic common part, their magnetic paths are coupled, leading to possible mutual magnetic-field interference and complex control. In this paper, a design method to ensure magnetic decoupling with minimum yoke thickness of the common rotor is investigated. A prototype machine is designed based on the proposed method, and the feasibility of magnetic decoupling and independent control is validated by experimental tests of mutual influence. The CS-PMSM is tested by a designed driving cycle, and functions to act as starter motor, generator and to help the internal combustion engine (ICE operate at optimum efficiency are validated.

Highly Selective and Sensitive Self-Powered Glucose Sensor Based on Capacitor Circuit.

Science.gov (United States)

Slaughter, Gymama; Kulkarni, Tanmay

2017-05-03

Enzymatic glucose biosensors are being developed to incorporate nanoscale materials with the biological recognition elements to assist in the rapid and sensitive detection of glucose. Here we present a highly sensitive and selective glucose sensor based on capacitor circuit that is capable of selectively sensing glucose while simultaneously powering a small microelectronic device. Multi-walled carbon nanotubes (MWCNTs) is chemically modified with pyrroloquinoline quinone glucose dehydrogenase (PQQ-GDH) and bilirubin oxidase (BOD) at anode and cathode, respectively, in the biofuel cell arrangement. The input voltage (as low as 0.25 V) from the biofuel cell is converted to a stepped-up power and charged to the capacitor to the voltage of 1.8 V. The frequency of the charge/discharge cycle of the capacitor corresponded to the oxidation of glucose. The biofuel cell structure-based glucose sensor synergizes the advantages of both the glucose biosensor and biofuel cell. In addition, this glucose sensor favored a very high selectivity towards glucose in the presence of competing and non-competing analytes. It exhibited unprecedented sensitivity of 37.66 Hz/mM.cm 2 and a linear range of 1 to 20 mM. This innovative self-powered glucose sensor opens new doors for implementation of biofuel cells and capacitor circuits for medical diagnosis and powering therapeutic devices.

Method of making a multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes

Science.gov (United States)

Farahmandi, C. Joseph; Dispennette, John M.; Blank, Edward; Kolb, Alan C.

2002-09-17

A single cell, multi-electrode high performance double layer capacitor includes first and second flat stacks of electrodes adapted to be housed in a closeable two-part capacitor case which includes only a single electrolyte seal. Each electrode stack has a plurality of electrodes connected in parallel, with the electrodes of one stack being interleaved with the electrodes of the other stack to form an interleaved stack, and with the electrodes of each stack being electrically connected to respective capacitor terminals. A porous separator is positioned against the electrodes of one stack before interleaving to prevent electrical shorts between the electrodes. The electrodes are made by folding a compressible, low resistance, aluminum-impregnated carbon cloth, made from activated carbon fibers, around a current collector foil, with a tab of the foils of each electrode of each stack being connected in parallel and connected to the respective capacitor terminal. The height of the interleaved stack is somewhat greater than the inside height of the closed capacitor case, thereby requiring compression of the interleaved electrode stack when placed inside of the case, and thereby maintaining the interleaved electrode stack under modest constant pressure. The closed capacitor case is filled with an electrolytic solution and sealed. A preferred electrolytic solution is made by dissolving an appropriate salt into acetonitrile (CH.sub.3 CN). In one embodiment, the two parts of the capacitor case are conductive and function as the capacitor terminals.

Self-discharge of AC/AC electrochemical capacitors in salt aqueous electrolyte

International Nuclear Information System (INIS)

García-Cruz, L.; Ratajczak, P.; Iniesta, J.; Montiel, V.; Béguin, F.

2016-01-01

The self-discharge (SD) of electrochemical capacitors based on activated carbon electrodes (AC/AC capacitors) in aqueous lithium sulfate was examined after applying a three-hour cell potential hold at U i values from 1.0 to 1.6 V. The leakage current measured during the potentiostatic period as well as the amplitude of self-discharge increased with U i ; the cell potential drop was approximately doubled by 10 °C increase of temperature. The potential decay of both negative and positive electrodes was explored separately, by introducing a reference electrode and it was found that the negative electrode contributes essentially to the capacitor self-discharge. A diffusion-controlled mechanism was found at U i ≤ 1.4 V and U i ≤ 1.2 V for the positive and negative electrodes, respectively. At higher U i of 1.6 V, both electrodes display an activation-controlled mechanism due to water oxidation and subsequent carbon oxidation at the positive electrode and water or oxygen reduction at the negative electrode.

Design and modeling of inductors, capacitors and coplanar waveguides at tens of GHz frequencies

CERN Document Server

Aryan, Naser Pour

2015-01-01

This book describes the basic principles of designing and modelling inductors, MIM capacitors and coplanar waveguides at frequencies of several tens of GHz. The author explains the design and modelling of key, passive elements, such as capacitors, inductors and transmission lines that enable high frequency MEMS operating at frequencies in the orders of tens of GHz.

Process Optimization of P(VDF-TrFE)-BaTiO3 Nanocomposites for Storage Capacitor Applications

KAUST Repository

Almadhoun, Mahmoud N.

2011-01-01

are considered to be one possible solution towards the fabrication of high energy density capacitors, whether as embedded capacitors or gate insulators in organic field effect transistors (OFETs). Selecting high permittivity ceramics mixed with polymers with high

Super dielectric capacitor using scaffold dielectric

OpenAIRE

Phillips, Jonathan

2018-01-01

Patent A capacitor having first and second electrodes and a scaffold dielectric. The scaffold dielectric comprises an insulating material with a plurality of longitudinal channels extending across the dielectric and filled with a liquid comprising cations and anions. The plurality of longitudinal channels are substantially parallel and the liquid within the longitudinal channels generally has an ionic strength of at least 0.1. Capacitance results from the migrations of...

Diagnostics system for the 67 MJ, 50 kV pulsed power capacitor bank

Energy Technology Data Exchange (ETDEWEB)

Galakhov, I V; Gasheev, A S; Gruzin, I A; Gudov, S N; Murugov, V M; Osin, V A; Pankratov, V I; Pegoev, I N [All-Russian Scientific Research Inst. of Experimental Physics, Sarov (Russian Federation)

1997-12-31

The diagnostics system is designed for charging and discharging to the load of the large 67 MJ and 50 kV capacitor bank for the iodine laser pulse power of ISKRA-5 facility. Discharging diagnostics of the capacitor bank uses a technique to measure a sequence of times between representative discharge events for 665 discharge circuits of the bank. Benefits of the measurement techniques are discussed. (author). 3 figs., 3 refs.

Diagnostics system for the 67 MJ, 50 kV pulsed power capacitor bank

International Nuclear Information System (INIS)

Galakhov, I.V.; Gasheev, A.S.; Gruzin, I.A.; Gudov, S.N.; Murugov, V.M.; Osin, V.A.; Pankratov, V.I.; Pegoev, I.N.

1996-01-01

The diagnostics system is designed for charging and discharging to the load of the large 67 MJ and 50 kV capacitor bank for the iodine laser pulse power of ISKRA-5 facility. Discharging diagnostics of the capacitor bank uses a technique to measure a sequence of times between representative discharge events for 665 discharge circuits of the bank. Benefits of the measurement techniques are discussed. (author). 3 figs., 3 refs

Effect of Reverse Bias Stress on Leakage Currents and Breakdown Voltages of Solid Tantalum Capacitors

Science.gov (United States)

Teverovsky, Alexander A.

2011-01-01

The majority of solid tantalum capacitors are produced by high-temperature sintering of a fine tantalum powder around a tantalum wire followed by electrolytic anodization that forms a thin amorphous Ta2O5 dielectric layer and pyrolysis of manganese nitrite on the oxide to create a conductive manganese dioxide electrode. A contact to tantalum wire is used as anode terminal and to the manganese layer as a cathode terminal of the device. This process results in formation of an asymmetric Ta -- Ta2O5 -- MnO2 capacitor that has different characteristics at forward (positive bias applied to tantalum) and reverse (positive bias applied to manganese cathode) voltages. Reverse bias currents might be several orders of magnitude larger than forward leakage currents so I-V characteristics of tantalum capacitors resemble characteristics of semiconductor rectifiers. Asymmetric I-V characteristics of Ta -- anodic Ta2O5 systems have been observed at different top electrode materials including metals, electrolytes, conductive polymers, and manganese oxide thus indicating that this phenomenon is likely related to the specifics of the Ta -- Ta2O5 interface. There have been multiple attempts to explain rectifying characteristics of capacitors employing anodic tantalum pentoxide dielectrics. A brief review of works related to reverse bias (RB) behavior of tantalum capacitors shows that the mechanism of conduction in Ta -- Ta2O5 systems is still not clear and more testing and analysis is necessary to understand the processes involved. If tantalum capacitors behave just as rectifiers, then the assessment of the safe reverse bias operating conditions would be a relatively simple task. Unfortunately, these parts can degrade with time under reverse bias significantly, and this further complicates analysis of the I-V characteristics and establishing safe operating areas of the parts. On other hand, time dependence of reverse currents might provide additional information for investigation of

Effect of interfacial layers on dielectric properties in very thin SrBi2Ta2O9 capacitors

International Nuclear Information System (INIS)

Moon, Bum-Ki; Isobe, Chiharu; Hironaka, Katsuyuki; Hishikawa, Shinichi

2001-01-01

The effect of interfacial layers on the dielectric properties in very thin SrBi 2 Ta 2 O 9 (SBT) capacitors has been investigated using static measurements. Total permittivity (ε t ) decreased as the film thickness was reduced in both Pt/SBT/Pt and Ir/SBT/Pt capacitors. The contribution of the interfacial capacitance (C int ) and bulk capacitance to the total capacitance indicates that C int of the Ir/SBT/Pt structure was lower than that of the Pt/SBT/Pt structure, while the bulk permittivity (ε b ) was essentially the same. The dispersion of all capacitors followed the power law, while the Ir/SBT/Pt capacitor showed a larger dispersion of C int . These results suggest that the Pt/SBT/Pt capacitor is preferred for obtaining the high performance with less effect of the interfacial layers on the dielectric properties. [copyright] 2001 American Institute of Physics

Evaluation of gamma and neutron irradiation effects on the properties of mica film capacitors

International Nuclear Information System (INIS)

Roy, Rajesh; Pandya, Arun

2005-01-01

We present an investigation of gamma and neutron radiation effects on mica film capacitors from an electrical point of view. We have studied quantitatively the effects of gamma and neutron irradiation on mica film capacitors of thickness, 20 and 40 μm (0.7874 and 1.5748 mil) with two different areas, 01 and 04 cm 2 . The capacitance has been measured at room temperature in the frequency range 100 Hz-10 MHz. Negligible change in the capacitance due to high gamma dose of 60 Co, 15 kGy at dose rate 0.25 kGy/h, has been observed. However, appreciable change in the capacitance has been observed due to low doses of fast neutrons (cumulative dose, 115 cGy) with flux ∼ 9.925 X 10 7 neutrons/cm 2 h from 252 Cf neutron source of fluence, 2.5 x 10 7 neutrons/s. We have also observed that the impact of gamma and neutron irradiation is more at frequencies higher than 10 kHz, These results show that the mica capacitors do not show any radiation response below 10 kHz. The study shows the radiation response of mica film capacitors to gamma and fast neutron radiations. Mica capacitors show low gamma radiation response in comparison to fast neutron radiation, because a total dose of kGy order has been given by gamma source and only few cGy dose has been given by fast neutron source. (author)

Pencil-on-Paper Capacitors for Hand-Drawn RC Circuits and Capacitive Sensing

Directory of Open Access Journals (Sweden)

Jonathan E. Thompson

2017-01-01

Full Text Available 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.

Performance and Safety of Lithium-ion Capacitors

Science.gov (United States)

Jeevarajan, Judith A.; Martinez, Martin D.

2014-01-01

Lithium-ion capacitors (LIC) are a recent innovation in the area of supercapacitors and ultracapacitors. With an operating voltage range similar to that of lithium-ion batteries and a very low selfdischarge rate, these can be readily used in the place of batteries especially when large currents are required to be stored safely for use at a later time.

Electronic detection of surface plasmon polaritons by metal-oxide-silicon capacitor

Directory of Open Access Journals (Sweden)

Robert E. Peale

2016-09-01

Full Text Available An electronic detector of surface plasmon polaritons (SPPs is reported. SPPs optically excited on a metal surface using a prism coupler are detected by using a close-coupled metal-oxide-silicon (MOS capacitor. Incidence-angle dependence is explained by Fresnel transmittance calculations, which also are used to investigate the dependence of photo-response on structure dimensions. Electrodynamic simulations agree with theory and experiment and additionally provide spatial intensity distributions on and off the SPP excitation resonance. Experimental dependence of the photoresponse on substrate carrier type, carrier concentration, and back-contact biasing is qualitatively explained by simple theory of MOS capacitors.

Geometrical splitting in Monte Carlo

International Nuclear Information System (INIS)

Dubi, A.; Elperin, T.; Dudziak, D.J.

1982-01-01

A statistical model is presented by which a direct statistical approach yielded an analytic expression for the second moment, the variance ratio, and the benefit function in a model of an n surface-splitting Monte Carlo game. In addition to the insight into the dependence of the second moment on the splitting parameters the main importance of the expressions developed lies in their potential to become a basis for in-code optimization of splitting through a general algorithm. Refs

Innovative wedge axe in making split firewood

International Nuclear Information System (INIS)

Mutikainen, A.

1998-01-01

Interteam Oy, a company located in Espoo, has developed a new method for making split firewood. The tools on which the patented System Logmatic are based are wedge axe and cylindrical splitting-carrying frame. The equipment costs about 495 FIM. The block of wood to be split is placed inside the upright carrying frame and split in a series of splitting actions using the innovative wedge axe. The finished split firewood remains in the carrying frame, which (as its name indicates) also serves as the means for carrying the firewood. This innovative wedge-axe method was compared with the conventional splitting of wood using an axe (Fiskars -handy 1400 splitting axe costing about 200 FIM) in a study conducted at TTS-Institute. There were eight test subjects involved in the study. In the case of the wedge-axe method, handling of the blocks to be split and of the finished firewood was a little quicker, but in actual splitting it was a little slower than the conventional axe method. The average productivity of splitting the wood and of the work stages related to it was about 0.4 m 3 per effective hour in both methods. The methods were also equivalent of one another in terms of the load imposed by the work when measured in terms of the heart rate. As regards work safety, the wedge-axe method was superior to the conventional method, but the continuous striking action and jolting transmitted to the arms were unpleasant (orig.)

Extracting renewable energy from a salinity difference using a capacitor.

Science.gov (United States)

Brogioli, Doriano

2009-07-31

Completely renewable energy can be produced by using water solutions of different salinity, like river water and sea water. Many different methods are already known, but development is still at prototype stage. Here I report a novel method, based on electric double-layer capacitor technology. Two porous electrodes, immersed in the salt solution, constitute a capacitor. It is first charged, then the salt solution is brought into contact with fresh water. The electrostatic energy increases as the salt concentration of the solution is reduced due to diffusion. This device can be used to turn sources of salinity difference into completely renewable sources of energy. An experimental demonstration is given, and performances and possible improvements are discussed.

TMD splitting functions in kT factorization. The real contribution to the gluon-to-gluon splitting

International Nuclear Information System (INIS)

Hentschinski, M.; Kusina, A.; Kutak, K.; Serino, M.

2018-01-01

We calculate the transverse momentum dependent gluon-to-gluon splitting function within k T -factorization, generalizing the framework employed in the calculation of the quark splitting functions in Hautmann et al. (Nucl Phys B 865:54-66, arXiv:1205.1759, 2012), Gituliar et al. (JHEP 01:181, arXiv:1511.08439, 2016), Hentschinski et al. (Phys Rev D 94(11):114013, arXiv:1607.01507, 2016) and demonstrate at the same time the consistency of the extended formalism with previous results. While existing versions of k T factorized evolution equations contain already a gluon-to-gluon splitting function i.e. the leading order Balitsky-Fadin-Kuraev-Lipatov (BFKL) kernel or the Ciafaloni-Catani-Fiorani-Marchesini (CCFM) kernel, the obtained splitting function has the important property that it reduces both to the leading order BFKL kernel in the high energy limit, to the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) gluon-to-gluon splitting function in the collinear limit as well as to the CCFM kernel in the soft limit. At the same time we demonstrate that this splitting kernel can be obtained from a direct calculation of the QCD Feynman diagrams, based on a combined implementation of the Curci-Furmanski-Petronzio formalism for the calculation of the collinear splitting functions and the framework of high energy factorization. (orig.)

Influence of test capacitor features on piezoelectric and dielectric measurement of ferroelectric films.

Science.gov (United States)

Wang, Zhihong; Lau, Gih Keong; Zhu, Weiguang; Chao, Chen

2006-01-01

This paper presents both theoretical and numerical analyses of the piezoelectric and dielectric responses of a highly idealized film-on-substrate system, namely, a polarized ferroelectric film perfectly bonded to an elastic silicon substrate. It shows that both effective dielectric and piezoelectric properties of the films change with the size and configuration of the test capacitor. There exists a critical electrode size that is smaller than the diameter of the commonly used substrate. The effective film properties converge to their respective constrained values as capacitor size increases to the critical size. If capacitor size is smaller than the critical size, the surface displacement at the top electrode deviates from the net thickness change in response to an applied voltage because the film is deformable at the film/substrate interface. The constrained properties of the films depend only on those of bulk ferroelectrics but are independent of film thickness and substrate properties. The finding of the critical capacitor size together with analytical expressions of the constrained properties makes it possible to realize consistent measurement of piezoelectric and dielectric properties of films. A surface scanning technique is recommended to measure the profile of piezoresponses of the film so that the constrained properties of the film can be identified accurately.

Fully inkjet printed RF inductors and capacitors using polymer dielectric and silver conductive ink with through vias

KAUST Repository

McKerricher, Garret

2015-03-01

In this paper, fully inkjet printed multilayer capacitors and inductors are fabricated and characterized using poly 4-vinylphenol (PVP) ink as the dielectric layer and silver nanoparticle ink as the conductor. Inkjet printed through vias, created with a novel dissolving method are used to make RF structures in a multilayer inkjet printing process. The vias have been realized in a 350-nm PVP film and exhibit resistance better than 0.1 Ω. Spiral inductors from 10 to 75 nH have been realized with maximum quality factors around five. The 10-nH inductor exhibits a self-resonant frequency slightly below 1 GHz. Metal-insulator-metal capacitors are realized with densities of 50 pF/mm-2. These capacitors demonstrate values ranging from 16 to 50 pF. The 16-pF capacitor shows a self-resonant frequency over 1.5 GHz. The successful implementation of inductors and capacitors in an all inkjet printed multilayer process with vias is an important step toward fully inkjet-printed large area and flexible RF systems.

Fully inkjet printed RF inductors and capacitors using polymer dielectric and silver conductive ink with through vias

KAUST Repository

McKerricher, Garret; Gonzalez Perez, Jose; Shamim, Atif

2015-01-01

In this paper, fully inkjet printed multilayer capacitors and inductors are fabricated and characterized using poly 4-vinylphenol (PVP) ink as the dielectric layer and silver nanoparticle ink as the conductor. Inkjet printed through vias, created with a novel dissolving method are used to make RF structures in a multilayer inkjet printing process. The vias have been realized in a 350-nm PVP film and exhibit resistance better than 0.1 Ω. Spiral inductors from 10 to 75 nH have been realized with maximum quality factors around five. The 10-nH inductor exhibits a self-resonant frequency slightly below 1 GHz. Metal-insulator-metal capacitors are realized with densities of 50 pF/mm-2. These capacitors demonstrate values ranging from 16 to 50 pF. The 16-pF capacitor shows a self-resonant frequency over 1.5 GHz. The successful implementation of inductors and capacitors in an all inkjet printed multilayer process with vias is an important step toward fully inkjet-printed large area and flexible RF systems.

Hybrid capacitor with activated carbon electrode, Ni(OH) 2 electrode and polymer hydrogel electrolyte

Science.gov (United States)

Nohara, Shinji; Asahina, Toshihide; Wada, Hajime; Furukawa, Naoji; Inoue, Hiroshi; Sugoh, Nozomu; Iwasaki, Hideharu; Iwakura, Chiaki

A new hybrid capacitor (HC) cell was assembled using an activated carbon (AC) negative electrode, an Ni(OH) 2 positive electrode and a polymer hydrogel electrolyte prepared from crosslinked potassium poly(acrylate) (PAAK) and KOH aqueous solution. The HC cell was characterized compared with an electric double layer capacitor (EDLC) using two AC electrodes and the polymer hydrogel electrolyte. It was found that the HC cell successfully worked in the larger voltage range and exhibited ca. 2.4 times higher capacitance than the EDLC cell. High-rate dischargeability of the HC cell was also superior to that of the EDLC cell. These improved characteristics strongly suggest that the HC cell can be a promising system of capacitors with high energy and power densities.

Capacitance of carbon-based electrical double-layer capacitors.

Science.gov (United States)

Ji, Hengxing; Zhao, Xin; Qiao, Zhenhua; Jung, Jeil; Zhu, Yanwu; Lu, Yalin; Zhang, Li Li; MacDonald, Allan H; Ruoff, Rodney S

2014-01-01

Experimental electrical double-layer capacitances of porous carbon electrodes fall below ideal values, thus limiting the practical energy densities of carbon-based electrical double-layer capacitors. Here we investigate the origin of this behaviour by measuring the electrical double-layer capacitance in one to five-layer graphene. We find that the capacitances are suppressed near neutrality, and are anomalously enhanced for thicknesses below a few layers. We attribute the first effect to quantum capacitance effects near the point of zero charge, and the second to correlations between electrons in the graphene sheet and ions in the electrolyte. The large capacitance values imply gravimetric energy storage densities in the single-layer graphene limit that are comparable to those of batteries. We anticipate that these results shed light on developing new theoretical models in understanding the electrical double-layer capacitance of carbon electrodes, and on opening up new strategies for improving the energy density of carbon-based capacitors.

Urban pattern: Layout design by hierarchical domain splitting

KAUST Repository

Yang, Yongliang; Wang, Jun; Vouga, Etienne; Wonka, Peter

2013-01-01

We present a framework for generating street networks and parcel layouts. Our goal is the generation of high-quality layouts that can be used for urban planning and virtual environments. We propose a solution based on hierarchical domain splitting using two splitting types: streamline-based splitting, which splits a region along one or multiple streamlines of a cross field, and template-based splitting, which warps pre-designed templates to a region and uses the interior geometry of the template as the splitting lines. We combine these two splitting approaches into a hierarchical framework, providing automatic and interactive tools to explore the design space.

Urban pattern: Layout design by hierarchical domain splitting

KAUST Repository

Yang, Yongliang

2013-11-06

We present a framework for generating street networks and parcel layouts. Our goal is the generation of high-quality layouts that can be used for urban planning and virtual environments. We propose a solution based on hierarchical domain splitting using two splitting types: streamline-based splitting, which splits a region along one or multiple streamlines of a cross field, and template-based splitting, which warps pre-designed templates to a region and uses the interior geometry of the template as the splitting lines. We combine these two splitting approaches into a hierarchical framework, providing automatic and interactive tools to explore the design space.

Nanoporous carbon for electrochemical capacitors.

Energy Technology Data Exchange (ETDEWEB)

Siegal, Michael P.; Bunker, Bruce Conrad; Limmer, Steven J.; Yelton, William Graham

2010-05-01

Nanoporous carbon (NPC) is a purely graphitic material with highly controlled densities ranging from less than 0.1 to 2.0 g/cm3, grown via pulsed-laser deposition. Decreasing the density of NPC increases the interplanar spacing between graphene-sheet fragments. This ability to tune the interplanar spacing makes NPC an ideal model system to study the behavior of carbon electrodes in electrochemical capacitors and batteries. We examine the capacitance of NPC films in alkaline and acidic electrolytes, and measure specific capacitances as high as 242 F/g.

Nanoporous carbon for electrochemical capacitors.

Energy Technology Data Exchange (ETDEWEB)

Overmyer, Donald L.; Siegal, Michael P.; Bunker, Bruce Conrad; Limmer, Steven J.; Yelton, William Graham

2010-04-01

Nanoporous carbon (NPC) is a purely graphitic material with highly controlled densities ranging from less than 0.1 to 2.0 g/cm3, grown via pulsed-laser deposition. Decreasing the density of NPC increases the interplanar spacing between graphene-sheet fragments. This ability to tune the interplanar spacing makes NPC an ideal model system to study the behavior of carbon electrodes in electrochemical capacitors and batteries. We examine the capacitance of NPC films in alkaline and acidic electrolytes, and measure specific capacitances as high as 242 F/g.

Nanocomposite multilayer capacitors comprising BaTiO3@TiO2 and poly(vinylidene fluoride-hexafluoropropylene for dielectric-based energy storage

Directory of Open Access Journals (Sweden)

Mojtaba Rahimabady

2014-04-01

Full Text Available Multilayer dielectric capacitors were fabricated from nanocomposite precursor comprised of BaTiO3@TiO2 core–shell nanosized particles and poly(vinylidene fluoride–hexafluoropropylene (P(VDF–HFP polymer matrix (20 vol%. The multilayer capacitors showed very high discharge speed and high discharged energy density of around 2.5 J/cm3 at its breakdown field (~ 166 MV/m. The energy density of the nanocomposite multilayer capacitors was substantially higher than the energy density of commercially used power capacitors. Low cost, flexible structure, high discharge rate and energy density suggest that the nanocomposite multilayer capacitors are promising for energy storage applications in many power devices and systems.

3-D analysis of eddy current in permanent magnet of interior permanent magnet motors

International Nuclear Information System (INIS)

Kawase, Yoshihiro; Yamaguchi, Tadashi; Fukanaga, Hiromu; Ito, Shokichi

2002-01-01

Interior permanent magnet motors are widely used in various fields. However, in high-speed operations, it is important to decrease the eddy current loss in the permanent magnet. In order to decrease the eddy current loss, we propose to divide the permanent magnet. In this paper, we clarified the effect of division of permanent magnet on the eddy current loss using the 3-D finite element method. (Author)

Comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement

International Nuclear Information System (INIS)

Stumberger, Bojan; Stumberger, Gorazd; Hadziselimovic, Miralem; Hamler, Anton; Gorican, Viktor; Jesenik, Marko; Trlep, Mladen

2007-01-01

The paper presents a comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement. Motors with the following permanent magnet topologies were accounted for in the comparison: the surface-mounted permanent magnet synchronous motor (SMPMSM), the interior permanent magnet synchronous motor (IPMSM), the permanent magnet-assisted synchronous reluctance motor (PMASRM) and the flux reversal permanent magnet motor (FRPMM). Finite element method analysis is employed to determine the performance of each motor. Calculated performance of four-pole IPMSM determined by finite element method calculation is confirmed with the measurements at nearly constant nominal output power in the range of speed 3000-10,000 rpm

A Different Approach to Studying the Charge and Discharge of a Capacitor without an Oscilloscope

Science.gov (United States)

Ladino, L. A.

2013-01-01

A different method to study the charging and discharging processes of a capacitor is presented. The method only requires a high impedance voltmeter. The charging and discharging processes of a capacitor are usually studied experimentally using an oscilloscope and, therefore, both processes are studied as a function of time. The approach presented…

Design and test of a flat-top magnetic field system driven by capacitor banks.

Science.gov (United States)

Jiang, Fan; Peng, Tao; Xiao, Houxiu; Zhao, Jianlong; Pan, Yuan; Herlach, Fritz; Li, Liang

2014-04-01

An innovative method for generating a flat-top pulsed magnetic field by means of capacitor banks is developed at the Wuhan National High Magnetic Field Center (WHMFC). The system consists of two capacitor banks as they are normally used to generate a pulsed field. The two discharge circuits (the magnet circuit and the auxiliary circuit) are coupled by a pulse transformer such that the electromotive force (EMF) induced via the transformer in the magnet circuit containing the magnet coil is opposed to the EMF of the capacitor bank. At a certain point before the current pulse in the coil reaches its peak, the auxiliary circuit is triggered. With optimized parameters for charging voltage and trigger delay, the current in the magnet circuit can be approximately kept constant to obtain a flat-top. A prototype was developed at the WHMFC; the magnet circuit was energized by seven 1 MJ (3.2 mF/25 kV) capacitor modules and the auxiliary circuit by four 1 MJ modules. Fields up to 41 T with 6 ms flat-top have been obtained with a conventional user magnet used at the WHMFC.

Integrated motor drive and non-isolated battery charger based on the split-phase PM motors for plug-in vehicles

Directory of Open Access Journals (Sweden)

Saeid Haghbin

2014-06-01

Full Text Available A novel integrated motor drive and non-isolated battery charger based on a split-phase permanent magnet (PM motor is presented and described for a plug-in vehicle. The motor windings are reconfigured by a relay for the traction and charging operation. In traction mode, the motor is like a normal three-phase motor, whereas in the charging mode, after windings reconnection, the system is a three-phase Boost rectifier. One important challenge to use the motor as three inductors in charger circuit is to have it in standstill during the battery charging. Based on the presented mathematical model of a split-phase PM motor, the zero-torque condition of the motor is explained which led to a proper windings reconnection for the charging. Simulation and experimental results of two separate practical systems are provided to verify the proposed integrated battery charger. Some practical limitations and design recommendations are provided to achieve a more realistic practical system.

Information processing through a bio-based redox capacitor: signatures for redox-cycling.

Science.gov (United States)

Liu, Yi; Kim, Eunkyoung; White, Ian M; Bentley, William E; Payne, Gregory F

2014-08-01

Redox-cycling compounds can significantly impact biological systems and can be responsible for activities that range from pathogen virulence and contaminant toxicities, to therapeutic drug mechanisms. Current methods to identify redox-cycling activities rely on the generation of reactive oxygen species (ROS), and employ enzymatic or chemical methods to detect ROS. Here, we couple the speed and sensitivity of electrochemistry with the molecular-electronic properties of a bio-based redox-capacitor to generate signatures of redox-cycling. The redox capacitor film is electrochemically-fabricated at the electrode surface and is composed of a polysaccharide hydrogel with grafted catechol moieties. This capacitor film is redox-active but non-conducting and can engage diffusible compounds in either oxidative or reductive redox-cycling. Using standard electrochemical mediators ferrocene dimethanol (Fc) and Ru(NH3)6Cl3 (Ru(3+)) as model redox-cyclers, we observed signal amplifications and rectifications that serve as signatures of redox-cycling. Three bio-relevant compounds were then probed for these signatures: (i) ascorbate, a redox-active compound that does not redox-cycle; (ii) pyocyanin, a virulence factor well-known for its reductive redox-cycling; and (iii) acetaminophen, an analgesic that oxidatively redox-cycles but also undergoes conjugation reactions. These studies demonstrate that the redox-capacitor can enlist the capabilities of electrochemistry to generate rapid and sensitive signatures of biologically-relevant chemical activities (i.e., redox-cycling). Published by Elsevier B.V.

Recombination chamber and a measuring system with sensitivity sufficient for in-flight and low-level dosimetry

International Nuclear Information System (INIS)

Zielczynski, M.; Golnik, N.; Shvidkij, S.V.

1996-01-01

A recombination chamber is proposed to be for determination of ambient dose equivalent, H*(10) during high-altitude flights and space missions. Polarizing electrodes of the chamber are supplied from two capacitors permanently connected to the electrodes. Ions, collected on the measuring electrode, charge a measuring capacitor that is also permanently connected to the electrode. The collected charge is proportional to H*(10), so the chamber with only three capacitors creates a whole measuring system. The special procedure was introduced for charging the supplying capacitors and for reading the voltage on the measuring capacitor. The procedure has to be performed in laboratory conditions before and after the flight. The measuring system with recombination chamber of REM-2 type allows to measure the H*(10) above 10 μSv with uncertainly ca. 25% in any field of penetration radiation, with an integration time up to some days. The system has been checked in field conditions. (author). 1 fig

Lifetime Estimation of DC-link Capacitors in a Single-phase Converter with an Integrated Active Power Decoupling Module

DEFF Research Database (Denmark)

Ma, Siyuan; Wang, Haoran; Tang, Junchaojie

2016-01-01

In single-phase inverters, DC-link capacitors are installed at the DC-link to buffer the ripple power between the AC side and DC side. Active decoupling methods introduce additional circuits at the DC side or AC side to partially or fully supply the ripple power. So that the demanded DC-link capa......In single-phase inverters, DC-link capacitors are installed at the DC-link to buffer the ripple power between the AC side and DC side. Active decoupling methods introduce additional circuits at the DC side or AC side to partially or fully supply the ripple power. So that the demanded DC......-link capacitor capacitance can be decreased. However, few research is about the effect of DC side and AC side decoupling on the DC-link capacitor reliability considering its electro-thermal stresses. This paper presents a quantitative analysis on the lifetime of capacitors with power decoupling circuits...... at the DC side and AC side, respectively. The ripple current spectrum of the capacitors is obtained by double Fourier analysis of a H-bridge inverter with natural sampling PWM modulation. A study case is demonstrated by a 2,000 W H-bridge inverter with 400 V DC-link voltage....

Plasma damage in floating metal-insulator-metal capacitors

NARCIS (Netherlands)

Ackaert, Jan; Wang, Zhichun; De Backer, E.; Coppens, P.

2002-01-01

In this paper, charging induced damage (CID) to metal-insulator-metal capacitors (MIMCs), is reported. CID does not necessarily lead to direct yield loss, but may also induce latent damage leading to reliability losses. The damage is caused by the build up of a voltage potential difference between

Plasma Damage in Floating Metal-Insulator-Metal Capacitors

NARCIS (Netherlands)

Ackaert, Jan; Wang, Zhichun; Backer, E.; Coppens, P.

2001-01-01

In this paper, charging induced damage (CID) to metal-insulator-metal capacitors (MIMCs), is reported. CID does not necessarily lead to direct yield loss, but may also induce latent damage leading to reliability losses. The damage is caused by the build up of a voltage potential difference between

Modulation of Molecular Flux Using a Graphene Nanopore Capacitor.

Science.gov (United States)

Shankla, Manish; Aksimentiev, Aleksei

2017-04-20

Modulation of ionic current flowing through nanoscale pores is one of the fundamental biological processes. Inspired by nature, nanopores in synthetic solid-state membranes are being developed to enable rapid analysis of biological macromolecules and to serve as elements of nanofludic circuits. Here, we theoretically investigate ion and water transport through a graphene-insulator-graphene membrane containing a single, electrolyte-filled nanopore. By means of all-atom molecular dynamics simulations, we show that the charge state of such a graphene nanopore capacitor can regulate both the selectivity and the magnitude of the nanopore ionic current. At a fixed transmembrane bias, the ionic current can be switched from being carried by an equal mixture of cations and anions to being carried almost exclusively by either cationic or anionic species, depending on the sign of the charge assigned to both plates of the capacitor. Assigning the plates of the capacitor opposite sign charges can either increase the nanopore current or reduce it substantially, depending on the polarity of the bias driving the transmembrane current. Facilitated by the changes of the nanopore surface charge, such ionic current modulations are found to occur despite the physical dimensions of the nanopore being an order of magnitude larger than the screening length of the electrolyte. The ionic current rectification is accompanied by a pronounced electro-osmotic effect that can transport neutral molecules such as proteins and drugs across the solid-state membrane and thereby serve as an interface between electronic and chemical signals.

Relationship between mandibular anatomy and the occurrence of a bad split upon sagittal split osteotomy.

Science.gov (United States)

Aarabi, Mohammadali; Tabrizi, Reza; Hekmat, Mina; Shahidi, Shoaleh; Puzesh, Ayatollah

2014-12-01

A bad split is a troublesome complication of the sagittal split osteotomy (SSO). The aim of this study was to evaluate the relation between the occurrence of a bad split and mandibular anatomy in SSO using cone-beam computed tomography. The authors designed a cohort retrospective study. Forty-eight patients (96 SSO sites) were studied. The buccolingual thickness of the retromandibular area (BLR), the buccolingual thickness of the ramus at the level of the lingula (BLTR), the height of the mandible from the alveolar crest to the inferior border of the mandible, (ACIB), the distance between the sigmoid notch and the inferior border of the mandible (SIBM), and the anteroposterior width of the ramus (APWR) were measured. The independent t test was applied to compare anatomic measurements between the group with and the group without bad splits. The receiver operating characteristic (ROC) test was used to find a cutoff point in anatomic size for various parts of the mandible related to the occurrence of bad splits. The mean SIBM was 47.05±6.33 mm in group 1 (with bad splits) versus 40.66±2.44 mm in group 2 (without bad splits; P=.01). The mean BLTR was 5.74±1.11 mm in group 1 versus 3.19±0.55 mm in group 2 (P=.04). The mean BLR was 14.98±2.78 mm in group 1 versus 11.21±1.29 mm in group 2 (P=.001). No statistically significant difference was found for APWR and ACIB between the 2 groups. The ROC test showed cutoff points of 10.17 mm for BLR, 36.69 mm for SIBM, and 4.06 mm for BLTR. This study showed that certain mandibular anatomic differences can increase the risk of a bad split during SSO surgery. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

On the evaluation of the capacitance of toroidal capacitors with a moon-shape meridian cross section

International Nuclear Information System (INIS)

Gongora T, A.; Ley-Koo, E.

1997-01-01

The toroidal capacitors studied in this paper consist of electrodes with meridian cross sections that are circular arcs meeting at the axis, and separated from each other by two small insulating spheres at their meeting points. The description and analysis of such capacitors is carried out by using bi spherical coordinates. The R-separability of the Laplace equation in these coordinates requires the use of the Green function technique, just like in the related problems of toroidal, spherical-cap-electrode, and bi spherical capacitors (1-3). An overall comparison of the solutions of the four problems is specially instructive. (Author)

Permanent quadrupole magnets

International Nuclear Information System (INIS)

Bush, E.D. Jr.

1976-01-01

A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. Based on preliminary tests, it was seen that permanent quadrupole magnets can offer a low cost, reliable solution in applications requiring small, fixed-field focusing devices for use in ion or electron-beam transport systems. Permanent magnets do require special considerations in design, fabrication, handling, and service that are different than encountered in conventional quadrupole magnets. If these basic conditions are satisfied, the resulting beam-focusing device would be stable, maintenance free, with virtually an indefinite lifetime

Anti-Ferroelectric Ceramics for High Energy Density Capacitors

Directory of Open Access Journals (Sweden)

Aditya Chauhan

2015-11-01

Full Text Available With an ever increasing dependence on electrical energy for powering modern equipment and electronics, research is focused on the development of efficient methods for the generation, storage and distribution of electrical power. In this regard, the development of suitable dielectric based solid-state capacitors will play a key role in revolutionizing modern day electronic and electrical devices. Among the popular dielectric materials, anti-ferroelectrics (AFE display evidence of being a strong contender for future ceramic capacitors. AFE materials possess low dielectric loss, low coercive field, low remnant polarization, high energy density, high material efficiency, and fast discharge rates; all of these characteristics makes AFE materials a lucrative research direction. However, despite the evident advantages, there have only been limited attempts to develop this area. This article attempts to provide a focus to this area by presenting a timely review on the topic, on the relevant scientific advancements that have been made with respect to utilization and development of anti-ferroelectric materials for electric energy storage applications. The article begins with a general introduction discussing the need for high energy density capacitors, the present solutions being used to address this problem, and a brief discussion of various advantages of anti-ferroelectric materials for high energy storage applications. This is followed by a general description of anti-ferroelectricity and important anti-ferroelectric materials. The remainder of the paper is divided into two subsections, the first of which presents various physical routes for enhancing the energy storage density while the latter section describes chemical routes for enhanced storage density. This is followed by conclusions and future prospects and challenges which need to be addressed in this particular field.

A Wireless Implantable Switched-Capacitor Based Optogenetic Stimulating System

Science.gov (United States)

Lee, Hyung-Min; Kwon, Ki-Yong; Li, Wen

2015-01-01

This paper presents a power-efficient implantable optogenetic interface using a wireless switched-capacitor based stimulating (SCS) system. The SCS efficiently charges storage capacitors directly from an inductive link and periodically discharges them into an array of micro-LEDs, providing high instantaneous power without affecting wireless link and system supply voltage. A custom-designed computer interface in LabVIEW environment wirelessly controls stimulation parameters through the inductive link, and an optrode array enables simultaneous neural recording along with optical stimulation. The 4-channel SCS system prototype has been implemented in a 0.35-μm CMOS process and combined with the optrode array. In vivo experiments involving light-induced local field potentials verified the efficacy of the SCS system. An implantable version of the SCS system with flexible hermetic sealing is under development for chronic experiments. PMID:25570099

High energy storage capacitor by embedding tunneling nano-structures

Science.gov (United States)

Holme, Timothy P; Prinz, Friedrich B; Van Stockum, Philip B

2014-11-04

In an All-Electron Battery (AEB), inclusions embedded in an active region between two electrodes of a capacitor provide enhanced energy storage. Electrons can tunnel to/from and/or between the inclusions, thereby increasing the charge storage density relative to a conventional capacitor. One or more barrier layers is present in an AEB to block DC current flow through the device. The AEB effect can be enhanced by using multi-layer active regions having inclusion layers with the inclusions separated by spacer layers that don't have the inclusions. The use of cylindrical geometry or wrap around electrodes and/or barrier layers in a planar geometry can enhance the basic AEB effect. Other physical effects that can be employed in connection with the AEB effect are excited state energy storage, and formation of a Bose-Einstein condensate (BEC).

Comparison of modified driver circuit and capacitor-transfer circuit in longitudinally excited N2 laser.

Science.gov (United States)

Uno, Kazuyuki; Akitsu, Tetsuya; Nakamura, Kenshi; Jitsuno, Takahisa

2013-04-01

We developed a modified driver circuit composed of a capacitance and a spark gap, called a direct-drive circuit, for a longitudinally excited gas laser. The direct-drive circuit uses a large discharge impedance caused by a long discharge length of the longitudinal excitation scheme and eliminates the buffer capacitance used in the traditional capacitor-transfer circuit. We compared the direct-drive circuit and the capacitor-transfer circuit in a longitudinally excited N2 laser (wavelength: 337 nm). Producing high output energy with the capacitor-transfer circuit requires a large storage capacitance and a discharge tube with optimum dimensions (an inner diameter of 4 mm and a length of 10 cm in this work); in contrast, the direct-drive circuit requires a high breakdown voltage, achieved with a small storage capacitance and a large discharge tube. Additionally, for the same input energy of 792 mJ, the maximum output energy of the capacitor-transfer circuit was 174.2 μJ, and that of the direct-drive circuit was 344.7 μJ.

Characteristics of Au/PZT/TiO2/Nitride/Si structure capacitors with ICP nitride treatments

International Nuclear Information System (INIS)

Min, Hyung Seob; Kim, Tae Ho; Jeon, Chang Bae; Lee, Jae Gab; Kim, Ji Young

2002-01-01

In this study, the characteristics of PZT/TiO 2 ferroelectric gate stack capacitors with Inductively Coupled Plasma (ICP) nitridation were investigated for field effect transistor (FET)-type Ferroelectric Random Access Memory (FeRAM) applications. If a high accumulation capacitance is to be had, the ICP nitridation time needs to be optimized. While a short ICP treatment time results in thermal oxide growth due to lack of nitrogen, a long nitridation time causes a nitride layer which is too thick. Au/PZT(200 nm)/TiO 2 (40 nm)/Nitride/Si (MeFINS) structure capacitors show a memory window (ΔV) of 1.6 V under ±3-V operation while Au/PZT(200 nm)/TiO 2 (40 nm)/Si (MeFIS) capacitors without nitride treatment exhibit a small memory window of 0.6 V. At the same time, the capacitance of the MeFINS device is almost twice that of the MeFIS capacitor. This result implies that the ICP nitride treatment suppresses the formation of a low dielectric constant interfacial SiO x layer and alleviates the series capacitance problem

Optimal placement of capacitors in a radial network using conic and mixed integer linear programming

Energy Technology Data Exchange (ETDEWEB)

Jabr, R.A. [Electrical, Computer and Communication Engineering Department, Notre Dame University, P.O. Box: 72, Zouk Mikhael, Zouk Mosbeh (Lebanon)

2008-06-15

This paper considers the problem of optimally placing fixed and switched type capacitors in a radial distribution network. The aim of this problem is to minimize the costs associated with capacitor banks, peak power, and energy losses whilst satisfying a pre-specified set of physical and technical constraints. The proposed solution is obtained using a two-phase approach. In phase-I, the problem is formulated as a conic program in which all nodes are candidates for placement of capacitor banks whose sizes are considered as continuous variables. A global solution of the phase-I problem is obtained using an interior-point based conic programming solver. Phase-II seeks a practical optimal solution by considering capacitor sizes as discrete variables. The problem in this phase is formulated as a mixed integer linear program based on minimizing the L1-norm of deviations from the phase-I state variable values. The solution to the phase-II problem is obtained using a mixed integer linear programming solver. The proposed method is validated via extensive comparisons with previously published results. (author)

Research on laser detonation pulse circuit with low-power based on super capacitor

Science.gov (United States)

Wang, Hao-yu; Hong, Jin; He, Aifeng; Jing, Bo; Cao, Chun-qiang; Ma, Yue; Chu, En-yi; Hu, Ya-dong

2018-03-01

According to the demand of laser initiating device miniaturization and low power consumption of weapon system, research on the low power pulse laser detonation circuit with super capacitor. Established a dynamic model of laser output based on super capacitance storage capacity, discharge voltage and programmable output pulse width. The output performance of the super capacitor under different energy storage capacity and discharge voltage is obtained by simulation. The experimental test system was set up, and the laser diode of low power pulsed laser detonation circuit was tested and the laser output waveform of laser diode in different energy storage capacity and discharge voltage was collected. Experiments show that low power pulse laser detonation based on super capacitor energy storage circuit discharge with high efficiency, good transient performance, for a low power consumption requirement, for laser detonation system and low power consumption and provide reference light miniaturization of engineering practice.

The Research of Super Capacitor and Battery Hybrid Energy Storage System with the THIPWM

Directory of Open Access Journals (Sweden)

Jianwei Ma

2014-02-01

Full Text Available It has to be considered that dynamic performance of Super Capacitor and Battery hybrid energy storage system is poor and the output waveform of AC voltage distorted seriously. The Third Harmonic Injection PWM (THIPWM with the three-level inverter, which has a excellent performance to improve the dynamic performance of the super capacitor and battery, gathers information from ends of the DC output voltage or current and the total current of the DC side to solve the problem of unbalanced neutral line voltage of three-level inverter .It also keeps super capacitor and battery controlled smoothly during the operation, and reduces the final output waveform distortion index. The simulation results verify the practicality and correctness of the three-level inverter topology and its control algorithm.

Evaluation of unencapsulated ceramic monolithic and MOS thin-film capacitors (25 to 3000C)

International Nuclear Information System (INIS)

Nance, W.R.

1982-01-01

Several commercial monolithic ceramic and thin-film MOS chip capacitors were evaluated for use in high temperature (300 0 C) geothermal instrumentation. Characteristics of the commonly used dielectric materials (NPO, X7R, BX) and temperature dependence of the insulation resistance are briefly discussed. Some ceramic capacitors with NPO dielectric materials had insulation resistances above 10 megohms at 300 0 C and less than 2% change in capacitance from 25 0 C to 300 0 C, while the X7R and BX dielectric materials exhibited insulation resistances below 10 megohm and changes in capacitance greater then 50%. The thin-film capacitors showed good stability at 300 0 C. However, during aging, bonds and bond pads presented a problem causing intermittently open circuits for some of the devices

Super capacitors for embarked systems as a storage energy device solution

Energy Technology Data Exchange (ETDEWEB)

Ayad, M.Y.; Rael, S.; Pierfederici, S.; Davat, B. [Institut National Polytechnique, GREEN-INPL-CNRS (UMR 7037), 54 - Vandoeuvre les Nancy (France)

2004-07-01

The management of embarked electrical energy needs a storage system with high dynamic performances, in order to shave transient power peaks and to compensate for the intrinsic limitations of the main source. The use of super-capacitors for this storage system is quite suitable, because of appropriate electrical characteristics (huge capacitance, weak serial resistance, high specific energy, high specific power), of direct storage (energy ready for use), and of easy control by power electronic conversion. This paper deals with the conception and the achievement of two hybrid power sources using super-capacitors as auxiliary storage device. We present the structures, the control principles, and some experimental results. (authors)

Metallopolymer capacitor in "one pot" by self-directed UV-assisted process.

Science.gov (United States)

Ijeri, Vijaykumar S; Nair, Jijeesh R; Gerbaldi, Claudio; Bongiovanni, Roberta M; Penazzi, Nerino

2010-11-01

Silver metalized methacrylate films are prepared by single-step UV curing process with good conductivity on both sides. The major component of the composite is Bisphenol A ethoxylate dimethacrylate, which can be photopolymerized by a photoreactive initiator under UV light. Under the same conditions of UV irradiation, silver ions are deposited as metal nanoparticles while the pyrrole is oxidized to polypyrrole. The migration of silver ions and pyrrole toward both surfaces during polymerization leads to the formation of a metallo-polymer capacitor. The composite films are characterized by SEM-EDX and electrical measurements for possible applications as capacitors in flexible and/or nonplanar electronics.

Discharging a DC bus capacitor of an electrical converter system

Science.gov (United States)

Kajouke, Lateef A; Perisic, Milun; Ransom, Ray M

2014-10-14

A system and method of discharging a bus capacitor of a bidirectional matrix converter of a vehicle are presented here. The method begins by electrically shorting the AC interface of the converter after an AC energy source is disconnected from the AC interface. The method continues by arranging a plurality of switching elements of a second energy conversion module into a discharge configuration to establish an electrical current path from a first terminal of an isolation module, through an inductive element, and to a second terminal of the isolation module. The method also modulates a plurality of switching elements of a first energy conversion module, while maintaining the discharge configuration of the second energy conversion module, to at least partially discharge a DC bus capacitor.

Carbon activation process for increased surface accessibility in electrochemical capacitors

Science.gov (United States)

Doughty, Daniel H.; Eisenmann, Erhard T.

2001-01-01

A process for making carbon film or powder suitable for double capacitor electrodes having a capacitance of up to about 300 F/cm.sup.3 is disclosed. This is accomplished by treating in aqueous nitric acid for a period of about 5 to 15 minutes thin carbon films obtained by carbonizing carbon-containing polymeric material having a high degree of molecular directionality, such as polyimide film, then heating the treated carbon film in a non-oxidizing atmosphere at a non-graphitizing temperature of at least 350.degree. C. for about 20 minutes, and repeating alternately the nitric acid step and the heating step from 7 to 10 times. Capacitors made with this carbon may find uses ranging from electronic devices to electric vehicle applications.

Optimal capacitor placement and sizing using combined fuzzy ...

African Journals Online (AJOL)

Then the sizing of the capacitors is modeled as an optimization problem and the objective function (loss minimization) is solved using Hybrid Particle Swarm Optimization (HPSO) technique. A case study with an IEEE 34 bus distribution feeder is presented to illustrate the applicability of the algorithm. A comparison is made ...

Irradiation effects of 6 MeV electron on electrical properties of Al/Al2O3/n-Si MOS capacitors

International Nuclear Information System (INIS)

Laha, P.; Banerjee, I.; Bajaj, A.; Chakraborty, P.; Barhai, P.K.; Dahiwale, S.S.; Das, A.K.; Bhoraskar, V.N.; Kim, D.; Mahapatra, S.K.

2012-01-01

The influence of 6 MeV electron irradiation on the electrical properties of Al/Al 2 O 3 /n-Si metal–oxide–semiconductor (MOS) capacitors has been investigated. Using rf magnetron sputtering deposition technique, Al/Al 2 O 3 /n-Si MOS capacitors were fabricated and such twelve capacitors were divided into four groups. The first group of MOS capacitors was not irradiated with 6 MeV electrons and treated as virgin. The second group, third group and fourth group of MOS capacitors were irradiated with 6 MeV electrons at 10 kGy, 20 kGy, and 30 kGy doses, respectively, keeping the dose rate ∼1 kGy/min. The variations in crystallinity of the virgin and irradiated MOS capacitors have been compared from GIXRD (Grazing Incidence X-ray Diffraction) spectra. Thickness and in-depth elemental distributions of individual layers were performed using Secondary Ion Mass Spectrometry (SIMS). The device parameters like flat band voltage (V FB ) and interface trap density (D it ) of virgin and irradiated MOS capacitors have been calculated from C vs V and G/ω vs V curve, respectively. The electrical properties of the capacitors were investigated from the tan δ vs V graph. The device parameters were estimated using C–V and G/ω–V measurements. Poole–Frenkel coefficient (β PF ) of the MOS capacitors was determined from leakage current (I)–voltage (V) measurement. The leakage current mechanism was proposed from the β PF value. - Highlights: ► The electron irradiation effects make variation in the device parameters. ► The device parameters changes due to percentage of defects and charge trapping. ► Leakage current of Al/Al 2 O 3 /n-Si changes due to interface dangling bonds. ► The leakage current mechanism of MOS structures is due to Poole-Frenkel effect.

Residual stresses in multilayer ceramic capacitors: measurement and computation

NARCIS (Netherlands)

Toonder, den J.M.J.; Rademaker, C.W.; Hu, C.L.

2003-01-01

In this paper, we present a combined experimental and computational study of the thermomechanical reliability of multilayer ceramic capacitors (MLCC's). We focus on residual stresses introduced into the components during the cooling down step of the sintering process. The technique of

Capacitor-less memory cell fabricated on nano-scale strained Si on a relaxed SiGe layer-on-insulator

International Nuclear Information System (INIS)

Kim, Tae-Hyun; Park, Jea-Gun

2013-01-01

We investigated the combined effect of the strained Si channel and hole confinement on the memory margin enhancement for a capacitor-less memory cell fabricated on nano-scale strained Si on a relaxed SiGe layer-on-insulator (ε-Si SGOI). The memory margin for the ε-Si SGOI capacitor-less memory cell was higher than that of the memory cell fabricated on an unstrained Si-on-insulator (SOI) and increased with increasing Ge concentration of the relaxed SiGe layer; i.e. the memory margin for the ε-Si SGOI capacitor-less memory cell (138.6 µA) at a 32 at% Ge concentration was 3.3 times higher than the SOI capacitor-less memory cell (43 µA). (paper)

The desing study of high voltage plasma focus for a large fluence neutron source by using a water capacitor bank

International Nuclear Information System (INIS)

Ueno, Isao; Kobata, Tadasuke

1983-01-01

A new possibility for high intensity neutron source (HINS) would be opened by the plasma focus device if we have a high voltage capacitor bank. A scaling law of neutron yield for D-T gas discharge in plasma focus device is obtained after Imshennik, Filippov and Filippova. The resulting scaling law shows the realizability of the D-T HINS by the use of plasma focus, provided that the device is operated under a high voltage condition. Until now, it has been difficult to construct the high voltage capacitor bank of long life, for example with V 0 =300kV, C 0 =200μF and L 0 --5nH necessary in the level of HINS. It becomes possible to design this capacitor bank by using the coaxial water capacitor which has been developed for the electron and ion beam accelerator. The size of a capacitor designed for V 0 =300kV, C 0 =1μF is phi5m x 22m. Two hundred capacitors are used in parallel in order to get the 200μF. (author)

Carbon-Based Materials for Lithium-Ion Batteries, Electrochemical Capacitors, and Their Hybrid Devices.