Nanohybrid capacitor: the next generation electrochemical capacitors

Energy Technology Data Exchange (ETDEWEB)

Naoi, K. [Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8558 (Japan)

2010-10-15

Conventional electric double layer capacitors (EDLC) designed with two symmetrical activated carbon electrodes can deliver substantially more power than similar size Li-ion batteries. There is presently a major effort to increase the energy density of EDLC s up to a target value in the vicinity of 20-30 Wh kg{sup -1}.The present review article deals with the recent contributions to get this high energy density and new approaches that have been made to increase the withstanding voltage of the EDLCs. Important alternative approach to meet this goal that is under serious investigation is to develop an asymmetric (hybrid) capacitors. Hybrid capacitor systems are the promising approach to meet the goal to effectively increase the energy density. The investigation is to develop hybrid capacitors has been initiated by Li-ion capacitors. And, now Nanohybrid capacitor certainly achieves as high energy density as Li-ion capacitors with higher stability, higher safety and higher productivity. This is the new lithium-ion based hybrid capacitor using the lithium titanate (Li{sub 4}Ti{sub 5}O{sub 12}) negative intercalation electrode that can operate at unusually high current densities. The high-rate Li{sub 4}Ti{sub 5}O{sub 12} negative electrode has a unique nano-structure consisting of unusually small nano-crystalline Li{sub 4}Ti{sub 5}O{sub 12} nucleated and grafted onto carbon nano-fiber anchors (nc-Li{sub 4}Ti{sub 5}O{sub 12}/CNF). (Abstract Copyright [2010], Wiley Periodicals, Inc.)

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...

EWS-FLI1 inhibits TNFα-induced NFκB-dependent transcription in Ewing sarcoma cells

International Nuclear Information System (INIS)

Lagirand-Cantaloube, Julie; Laud, Karine; Lilienbaum, Alain; Tirode, Franck; Delattre, Olivier; Auclair, Christian; Kryszke, Marie-Helene

2010-01-01

Research highlights: → EWS-FLI1 interferes with TNF-induced activation of NFκB in Ewing sarcoma cells. → EWS-FLI1 knockdown in Ewing sarcoma cells increases TNF-induced NFκB binding to DNA. → EWS-FLI1 reduces TNF-stimulated NFκB-dependent transcriptional activation. → Constitutive NFκB activity is not affected by EWS-FLI1. → EWS-FLI1 physically interacts with NFκB p65 in vivo. -- Abstract: Ewing sarcoma is primarily caused by a t(11;22) chromosomal translocation encoding the EWS-FLI1 fusion protein. To exert its oncogenic function, EWS-FLI1 acts as an aberrant transcription factor, broadly altering the gene expression profile of tumor cells. Nuclear factor-kappaB (NFκB) is a tightly regulated transcription factor controlling cell survival, proliferation and differentiation, as well as tumorigenesis. NFκB activity is very low in unstimulated Ewing sarcoma cells, but can be induced in response to tumor necrosis factor (TNF). We wondered whether NFκB activity could be modulated by EWS-FLI1 in Ewing sarcoma. Using a knockdown approach in Ewing sarcoma cells, we demonstrated that EWS-FLI1 has no influence on NFκB basal activity, but impairs TNF-induced NFκB-driven transcription, at least in part through inhibition of NFκB binding to DNA. We detected an in vivo physical interaction between the fusion protein and NFκB p65, which could mediate these effects. Our findings suggest that, besides directly controlling the activity of its primary target promoters, EWS-FLI1 can also indirectly influence gene expression in tumor cells by modulating the activity of key transcription factors such as NFκB.

EWS/FLI-l peptide-pulsed dendritic cells induces the antitumor immunity in a murine Ewing's sarcoma cell model.

Science.gov (United States)

Peng, Wei; Huang, Xunwu; Yang, Dazhi

2014-08-01

An increasing number of T-cell epitopes derived from various tumor-associated antigens have been reported, and they proved to play significant roles for tumor rejection both in vivo and in vitro. Over 85% of Ewing's sarcoma family of tumors (ESFTs) express tumor-specific chimeric protein EWS/FLI-1, making it an attractive target for therapeutic cytotoxic T-lymphocyte responses. Here, we identified a novel peptide epitope derived from the EWS/FLI-1 protein and demonstrated that effectors induced by the peptide could specifically secrete IFN-γ and lyse the tumor cell line of EWS/FLI-1-positive and HLA-matched cells. In addition, mice treated with dendritic cells pulsed with the EWS/FLI-1 epitope were able to reject a lethal tumor inoculation of the Ewing's sarcoma A673 cells. Therefore, these data provide evidence for the use of the EWS/FLI-l peptide epitope in T cell-based immunotherapeutic concepts against Ewing's sarcoma cell in vitro and in vivo. Copyright © 2014 Elsevier B.V. All rights reserved.

Super-capacitors fuel-cell hybrid electric vehicle optimization and control strategy development

International Nuclear Information System (INIS)

Paladini, Vanessa; Donateo, Teresa; De Risi, Arturo; Laforgia, Domenico

2007-01-01

In the last decades, due to emissions reduction policies, research focused on alternative powertrains among which hybrid electric vehicles (HEVs) powered by fuel cells are becoming an attractive solution. One of the main issues of these vehicles is the energy management in order to improve the overall fuel economy. The present investigation aims at identifying the best hybrid vehicle configuration and control strategy to reduce fuel consumption. The study focuses on a car powered by a fuel cell and equipped with two secondary energy storage devices: batteries and super-capacitors. To model the powertrain behavior an on purpose simulation program called ECoS has been developed in Matlab/Simulink environment. The fuel cell model is based on the Amphlett theory. The battery and the super-capacitor models account for charge/discharge efficiency. The analyzed powertrain is also equipped with an energy regeneration system to recover braking energy. The numerical optimization of vehicle configuration and control strategy of the hybrid electric vehicle has been carried out with a multi objective genetic algorithm. The goal of the optimization is the reduction of hydrogen consumption while sustaining the battery state of charge. By applying the algorithm to different driving cycles, several optimized configurations have been identified and discussed

Impact of Switching Harmonics on Capacitor Cells Balancing in Phase-Shifted PWM-Based Cascaded H-Bridge STATCOM

DEFF Research Database (Denmark)

Behrouzian, Ehsan; Bongiorno, Massimo; Teodorescu, Remus

2017-01-01

is investigated and the interaction between voltage and current harmonics is analyzed. It is shown that in both cases, this interaction results in an uneven power distribution among the cells in the same phase leg, leading to drifting of the dc-capacitor voltages and thereby the need for proper stabilization...... contributing to the capacitors balancing. A methodology for optimal selection of the frequency modulation ratio is given. Theoretical conclusions are validated through simulation and experimental results....

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.

Calcium homeostasis in fly photoreceptor cells

NARCIS (Netherlands)

Oberwinkler, J

2002-01-01

In fly photoreceptor cells, two processes dominate the Ca2+ homeostasis: light-induced Ca2+ influx through members of the TRP family of ion channels, and Ca2+ extrusion by Na+/Ca2+ exchange.Ca2+ release from intracellular stores is quantitatively insignificant. Both, the light-activated channels and

Split-phase motor running as capacitor starts motor and as capacitor run motor

Directory of Open Access Journals (Sweden)

Yahaya Asizehi ENESI

2016-07-01

Full Text Available In this paper, the input parameters of a single phase split-phase induction motor is taken to investigate and to study the output performance characteristics of capacitor start and capacitor run induction motor. The value of these input parameters are used in the design characteristics of capacitor run and capacitor start motor with each motor connected to rated or standard capacitor in series with auxiliary winding or starting winding respectively for the normal operational condition. The magnitude of capacitor that will develop maximum torque in capacitor start motor and capacitor run motor are investigated and determined by simulation. Each of these capacitors is connected to the auxiliary winding of split-phase motor thereby transforming it into capacitor start or capacitor run motor. The starting current and starting torque of the split-phase motor (SPM, capacitor run motor (CRM and capacitor star motor (CSM are compared for their suitability in their operational performance and applications.

Structural integrity of ceramic multilayer capacitor materials and ceramic multilayer capacitors

NARCIS (Netherlands)

With, de G.

1993-01-01

An review with 61 refs. is given of the fracture of and stress situation in ceramic capacitor materials and ceramic multilayer capacitors. A brief introduction to the relevant concepts is given first. Next the data for capacitor materials and the data for capacitors are discussed. The materials data

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

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...

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.

Design of an hybrid source with fuel cell and super-capacitors; Conception d'une source hybride utilisant une pile a combustible et des supercondensateurs

Energy Technology Data Exchange (ETDEWEB)

Thounthong, Ph

2005-12-15

The design and testing of a purely super-capacitor energy storage device as auxiliary power source in electrical vehicle applications having a PEM fuel cell as main source are presented. The two control strategies are explained. The control algorithms are that fuel cell is simply operating in almost steady state conditions in order to lessen the mechanical stresses of fuel cell and to ensure a good synchronization between fuel flow and fuel cell current. Super-capacitors are functioning during absence of energy from fuel cell, transient energy delivery or transient energy recovery. The system utilizes two modules of SAFT super-capacitive storage device. This device is connected to a 42 V DC bus by a 2-quadrant dc/dc converter, and fuel cell is connected to the dc bus by a boost converter. The system structure is realized by analogical current loops and digital control (dSPACE) for voltage loops and estimation algorithms. Experimental results with a 500 W PEM fuel cell point out the slow dynamics naturally of fuel cell because of thermodynamic and mechanical operation, and also substantiate that the super-capacitors can improve dynamics and power conditioning for automotive electrical system. (author)

Electrically tuned super-capacitors

OpenAIRE

Chowdhury, Tazima S.; Grebel, Haim

2015-01-01

Fast charging and discharging of large amounts of electrical energy make super-capacitors ideal for short-term energy storage [1-5]. In its simplest form, the super-capacitor is an electrolytic capacitor made of an anode and a cathode immersed in an electrolyte. As for an ordinary capacitor, minimizing the charge separation distance and increasing the electrode area increase capacitance. In super-capacitors, charge separation is of nano-meter scale at each of the electrode interface (the Helm...

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.

Split-phase motor running as capacitor starts motor and as capacitor run motor

OpenAIRE

Yahaya Asizehi ENESI; Jacob TSADO; Mark NWOHU; Usman Abraham USMAN; Odu Ayo IMORU

2016-01-01

In this paper, the input parameters of a single phase split-phase induction motor is taken to investigate and to study the output performance characteristics of capacitor start and capacitor run induction motor. The value of these input parameters are used in the design characteristics of capacitor run and capacitor start motor with each motor connected to rated or standard capacitor in series with auxiliary winding or starting winding respectively for the normal operational condition. The ma...

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.

Current Controller for Multi-level Front-end Converter and Its Digital Implementation Considerations on Three-level Flying Capacitor Topology

Science.gov (United States)

Tekwani, P. N.; Shah, M. T.

2017-10-01

This paper presents behaviour analysis and digital implementation of current error space phasor based hysteresis controller applied to three-phase three-level flying capacitor converter as front-end topology. The controller is self-adaptive in nature, and takes the converter from three-level to two-level mode of operation and vice versa, following various trajectories of sector change with the change in reference dc-link voltage demanded by the load. It keeps current error space phasor within the prescribed hexagonal boundary. During the contingencies, the proposed controller takes the converter in over modulation mode to meet the load demand, and once the need is satisfied, controller brings back the converter in normal operating range. Simulation results are presented to validate behaviour of controller to meet the said contingencies. Unity power factor is assured by proposed controller with low current harmonic distortion satisfying limits prescribed in IEEE 519-2014. Proposed controller is implemented using TMS320LF2407 16-bit fixed-point digital signal processor. Detailed analysis of numerical format to avoid overflow of sensed variables in processor, and per-unit model implementation in software are discussed and hardware results are presented at various stages of signal conditioning to validate the experimental setup. Control logic for the generation of reference currents is implemented in TMS320LF2407A using assembly language and experimental results are also presented for the same.

Design of an hybrid source with fuel cell and super-capacitors; Conception d'une source hybride utilisant une pile a combustible et des supercondensateurs

Energy Technology Data Exchange (ETDEWEB)

Thounthong, Ph.

2005-12-15

The design and testing of a purely super-capacitor energy storage device as auxiliary power source in electrical vehicle applications having a PEM fuel cell as main source are presented. The two control strategies are explained. The control algorithms are that fuel cell is simply operating in almost steady state conditions in order to lessen the mechanical stresses of fuel cell and to ensure a good synchronization between fuel flow and fuel cell current. Super-capacitors are functioning during absence of energy from fuel cell, transient energy delivery or transient energy recovery. The system utilizes two modules of SAFT super-capacitive storage device. This device is connected to a 42 V DC bus by a 2-quadrant dc/dc converter, and fuel cell is connected to the dc bus by a boost converter. The system structure is realized by analogical current loops and digital control (dSPACE) for voltage loops and estimation algorithms. Experimental results with a 500 W PEM fuel cell point out the slow dynamics naturally of fuel cell because of thermodynamic and mechanical operation, and also substantiate that the super-capacitors can improve dynamics and power conditioning for automotive electrical system. (author)

Vented Capacitor

Science.gov (United States)

Brubaker, Michael Allen; Hosking, Terry Alan

2006-04-11

A technique of increasing the corona inception voltage (CIV), and thereby increasing the operating voltage, of film/foil capacitors is described. Intentional venting of the capacitor encapsulation improves the corona inception voltage by allowing internal voids to equilibrate with the ambient environment.

Analysis of stationary fuel cell dynamic ramping capabilities and ultra capacitor energy storage using high resolution demand data

Science.gov (United States)

Meacham, James R.; Jabbari, Faryar; Brouwer, Jacob; Mauzey, Josh L.; Samuelsen, G. Scott

Current high temperature fuel cell (HTFC) systems used for stationary power applications (in the 200-300 kW size range) have very limited dynamic load following capability or are simply base load devices. Considering the economics of existing electric utility rate structures, there is little incentive to increase HTFC ramping capability beyond 1 kWs -1 (0.4% s -1). However, in order to ease concerns about grid instabilities from utility companies and increase market adoption, HTFC systems will have to increase their ramping abilities, and will likely have to incorporate electrical energy storage (EES). Because batteries have low power densities and limited lifetimes in highly cyclic applications, ultra capacitors may be the EES medium of choice. The current analyses show that, because ultra capacitors have a very low energy storage density, their integration with HTFC systems may not be feasible unless the fuel cell has a ramp rate approaching 10 kWs -1 (4% s -1) when using a worst-case design analysis. This requirement for fast dynamic load response characteristics can be reduced to 1 kWs -1 by utilizing high resolution demand data to properly size ultra capacitor systems and through demand management techniques that reduce load volatility.

Hybrid capacitor with activated carbon electrode, Ni(OH){sub 2} electrode and polymer hydrogel electrolyte

Energy Technology Data Exchange (ETDEWEB)

Nohara, Shinji; Asahina, Toshihide; Wada, Hajime; Furukawa, Naoji; Inoue, Hiroshi; Iwakura, Chiaki [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan); Sugoh, Nozomu; Iwasaki, Hideharu [Kurashiki Research Laboratory, Kuraray Co., Ltd., 2045-1 Sakazu, Kurashiki, Okayama 710-8691 (Japan)

2006-06-19

A new hybrid capacitor (HC) cell was assembled using an activated carbon (AC) negative electrode, an Ni(OH){sub 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. (author)

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.

Using super-capacitors in combination with Bi-directional DC/DC converters for active load management in residential fuel cell applications

Energy Technology Data Exchange (ETDEWEB)

Cacciato, M.; Giulii Capponi, F. [Rome Univ., ' La Sapienza' , Dept. of Electrical Engineering (Italy)

2004-07-01

Among innovative conversion systems for alternative energy, Fuel Cells (FCs) are ideal in applications as distributed power generation or automotive. The connection of FCs to domestic or industrial loads requires a DC/AC converter also acting as a energy buffer to match the different dynamics of FCs and loads. In the last years, a new type of electrolytic capacitors called Super- Capacitors (SCs), has been designed using double layers technology. Such components are able to store more energy than electrolytic capacitors maintaining the capability to swap it at high power levels. Firstly, different solution used to connect SCs to a FC based conversion system are considered. Then, a comparison of bi-directional DC/DC converters designed to manage SCs energy is performed. Finally, the converter design and a laboratory prototype of the adopted solution are reported. (authors)

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.

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

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

The effect of Beauveria bassiana infection on cell mediated and humoral immune response in house fly, Musca domestica L.

Science.gov (United States)

Mishra, Sapna; Kumar, Peeyush; Malik, Anushree

2015-10-01

Entomopathogenic fungi that manifest infections by overcoming insect's immune response could be a successful control agent for the house fly, Musca domestica L. which is a major domestic, medical, and veterinary pest. In this study, the immune response of house fly to Beauveria bassiana infection was investigated to reveal fundamental aspects of house fly hemocyte biology, such as hemocyte numbers and size, which is poorly understood. The total hemocyte counts (THCs) in B. bassiana-infected house fly showed an initial increase (from 6 to 9 h), followed by subsequent decrease (9 to 12 h) with increase in time of infection. The THCs was slightly greater in infected flies than the non-infected ones. Insight into relative hemocyte counts depicted a significant increase in prohemocyte (PR) and decrease in granulocyte (GR) in infected house flies compared to non-infected ones. The relative cell area of hemocyte cells showed a noticeable increase in PR and intermediate cells (ICs), while a considerable reduction was observed for plasmatocyte (PL) and GR. The considerable variation in relative cell number and cell area in the B. bassiana-infected house flies indicated stress development during infection. The present study highlights changes occurring during B. bassiana invasion to house fly leading to establishment of infection along with facilitation in understanding of basic hemocyte biology. The results of the study is expected to help in better understanding of house fly immune response during fungal infection, so as to assist production of more efficient mycoinsecticides for house fly control using B. bassiana.

A multi-level capacitor-less memory cell fabricated on a nano-scale strained silicon-on-insulator

International Nuclear Information System (INIS)

Park, Jea-Gun; Kim, Seong-Je; Shin, Mi-Hee; Song, Seung-Hyun; Shim, Tae-Hun; Chung, Sung-Woong; Enomoto, Hirofumi

2011-01-01

A multi-level capacitor-less memory cell was fabricated with a fully depleted n-metal-oxide-semiconductor field-effect transistor on a nano-scale strained silicon channel on insulator (FD sSOI n-MOSFET). The 0.73% biaxial tensile strain in the silicon channel of the FD sSOI n-MOSFET enhanced the effective electron mobility to ∼ 1.7 times that with an unstrained silicon channel. This thereby enables both front- and back-gate cell operations, demonstrating eight-level volatile memory-cell operation with a 1 ms retention time and 12 μA memory margin. This is a step toward achieving a terabit volatile memory cell.

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

On-Orbit Demonstration of a Lithium-Ion Capacitor and Thin-Film Multijunction Solar Cells

Science.gov (United States)

Kukita, Akio; Takahashi, Masato; Shimazaki, Kazunori; Kobayashi, Yuki; Sakai, Tomohiko; Toyota, Hiroyuki; Takahashi, Yu; Murashima, Mio; Uno, Masatoshi; Imaizumi, Mitsuru

2014-08-01

This paper describes an on-orbit demonstration of the Next-generation Small Satellite Instrument for Electric power systems (NESSIE) on which an aluminum- laminated lithium-ion capacitor (LIC) and a lightweight solar panel called KKM-PNL, which has space solar sheets using thin-film multijunction solar cells, were installed. The flight data examined in this paper covers a period of 143 days from launch. We verified the integrity of an LIC constructed using a simple and lightweight mounting method: no significant capacitance reduction was observed. We also confirmed that inverted metamorphic multijunction triple-junction thin-film solar cells used for evaluation were healthy at 143 days after launch, because their degradation almost matched the degradation predictions for dual-junction thin-film solar cells.

FOXO1 is a direct target of EWS-Fli1 oncogenic fusion protein in Ewing's sarcoma cells

International Nuclear Information System (INIS)

Yang, Liu; Hu, Hsien-Ming; Zielinska-Kwiatkowska, Anna; Chansky, Howard A.

2010-01-01

Research highlights: → Inducible and reversible siRNA knockdown of an oncogenic fusion protein such as EWS-Fli1 is feasible and more advantageous than other siRNA methods. → The tumor suppressor gene FOXO1 is a new EWS-Fli1 target. → While trans-activators are known for the FOXO1 gene, there has been no report on negative regulators of FOXO1 transcription. → This study provides first evidence that the EWS-Fli1 oncogenic fusion protein can function as a transcriptional repressor of the FOXO1 gene. -- Abstract: Ewing's family tumors are characterized by a specific t(11;22) chromosomal translocation that results in the formation of EWS-Fli1 oncogenic fusion protein. To investigate the effects of EWS-Fli1 on gene expression, we carried out DNA microarray analysis after specific knockdown of EWS-Fli1 through transfection of synthetic siRNAs. EWS-Fli1 knockdown increased expression of genes such as DKK1 and p57 that are known to be repressed by EWS-Fli1 fusion protein. Among other potential EWS-Fli1 targets identified by our microarray analysis, we have focused on the FOXO1 gene since it encodes a potential tumor suppressor and has not been previously reported in Ewing's cells. To better understand how EWS-Fli1 affects FOXO1 expression, we have established a doxycycline-inducible siRNA system to achieve stable and reversible knockdown of EWS-Fli1 in Ewing's sarcoma cells. Here we show that FOXO1 expression in Ewing's cells has an inverse relationship with EWS-Fli1 protein level, and FOXO1 promoter activity is increased after doxycycline-induced EWS-Fli1 knockdown. In addition, we have found that direct binding of EWS-Fli1 to FOXO1 promoter is attenuated after doxycycline-induced siRNA knockdown of the fusion protein. Together, these results suggest that suppression of FOXO1 function by EWS-Fli1 fusion protein may contribute to cellular transformation in Ewing's family tumors.

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.

New series half-bridge converters with the balance input split capacitor voltages

Science.gov (United States)

Lin, Bor-Ren; Chiang, Huann-Keng; Wang, Shang-Lun

2016-03-01

This article presents a new dc/dc converter to perform the main functions of zero voltage switching (ZWS), low converter size, high switching frequency and low-voltage stress. Metal-oxide-semiconductor field-effect transistors (MOSFETs) with high switching frequency are used to reduce the converter size and increase circuit efficiency. To overcome low-voltage stress and high turn-on resistance of MOSFETs, the series half-bridge topology is adopted in the proposed converter. Hence, the low-voltage stress MOSFETs can be used for medium-input voltage applications. The asymmetric pulse-width modulation is used to generate the gating signals and achieve the ZWS. On the secondary side, the parallel connection of two diode rectifiers is adopted to reduce the current rating of passive components. On the primary side, the series connection of two transformers is used to balance two output inductor currents. Two flying capacitors are used to automatically balance the input split capacitor voltages. Finally, experiments with 1000 W rated power are performed to verify the theoretical analysis and the effectiveness of proposed converter.

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)

Substituted Quaternary Ammonium Salts Improve Low-Temperature Performance of Double-Layer Capacitors

Science.gov (United States)

Brandon, Erik J.; Smart, Marshall C.; West, William C.

2011-01-01

Double-layer capacitors are unique energy storage devices, capable of supporting large current pulses as well as a very high number of charging and discharging cycles. The performance of doublelayer capacitors is highly dependent on the nature of the electrolyte system used. Many applications, including for electric and fuel cell vehicles, back-up diesel generators, wind generator pitch control back-up power systems, environmental and structural distributed sensors, and spacecraft avionics, can potentially benefit from the use of double-layer capacitors with lower equivalent series resistances (ESRs) over wider temperature limits. Higher ESRs result in decreased power output, which is a particular problem at lower temperatures. Commercially available cells are typically rated for operation down to only 40 C. Previous briefs [for example, Low Temperature Supercapacitors (NPO-44386), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), p. 32, and Supercapacitor Electrolyte Solvents With Liquid Range Below 80 C (NPO-44855), NASA Tech Briefs, Vol. 34, No. 1 (January 2010), p. 44] discussed the use of electrolytes that employed low-melting-point co-solvents to depress the freezing point of traditional acetonitrile-based electrolytes. Using these modified electrolyte formulations can extend the low-temperature operational limit of double-layer capacitors beyond that of commercially available cells. This previous work has shown that although the measured capacitance is relatively insensitive to temperature, the ESR can rise rapidly at low temperatures, due to decreased electrolyte conductance within the pores of the high surface- area carbon electrodes. Most of these advanced electrolyte systems featured tetraethylammonium tetrafluoroborate (TEATFB) as the salt. More recent work at JPL indicates the use of the asymmetric quaternary ammonium salt triethylmethylammonium tetrafluoroborate (TEMATFB) or spiro-(l,l')-bipyrrolidium tetrafluoroborate (SBPBF4) in a 1:1 by volume solvent

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.

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

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.

A New Time Calibration Method for Switched-capacitor-array-based Waveform Samplers.

Science.gov (United States)

Kim, H; Chen, C-T; Eclov, N; Ronzhin, A; Murat, P; Ramberg, E; Los, S; Moses, W; Choong, W-S; Kao, C-M

2014-12-11

We have developed a new time calibration method for the DRS4 waveform sampler that enables us to precisely measure the non-uniform sampling interval inherent in the switched-capacitor cells of the DRS4. The method uses the proportionality between the differential amplitude and sampling interval of adjacent switched-capacitor cells responding to a sawtooth-shape pulse. In the experiment, a sawtooth-shape pulse with a 40 ns period generated by a Tektronix AWG7102 is fed to a DRS4 evaluation board for calibrating the sampling intervals of all 1024 cells individually. The electronic time resolution of the DRS4 evaluation board with the new time calibration is measured to be ~2.4 ps RMS by using two simultaneous Gaussian pulses with 2.35 ns full-width at half-maximum and applying a Gaussian fit. The time resolution dependencies on the time difference with the new time calibration are measured and compared to results obtained by another method. The new method could be applicable for other switched-capacitor-array technology-based waveform samplers for precise time calibration.

700 F hybrid capacitors cells composed of activated carbon and Li4Ti5O12 microspheres with ultra-long cycle life

Science.gov (United States)

Ruan, Dianbo; Kim, Myeong-Seong; Yang, Bin; Qin, Jun; Kim, Kwang-Bum; Lee, Sang-Hyun; Liu, Qiuxiang; Tan, Lei; Qiao, Zhijun

2017-10-01

To address the large-scale application demands of high energy density, high power density, and long cycle lifetime, 700-F hybrid capacitor pouch cells have been prepared, comprising ∼240-μm-thick activated carbon cathodes, and ∼60-μm-thick Li4Ti5O12 anodes. Microspherical Li4Ti5O12 (M-LTO) synthesized by spray-drying features 200-400 nm primary particles and interconnected nanopore structures. M-LTO half-cells exhibits high specific capacities (175 mAhh g-1), good rate capabilities (148 mAhh g-1 at 20 C), and ultra-long cycling stabilities (90% specific capacity retention after 10,000 cycles). In addition, the obtained hybrid capacitors comprising activated carbon (AC) and M-LTO shows excellent cell performances, achieving a maximum energy density of 51.65 Wh kg-1, a maximum power density of 2466 W kg-1, and ∼92% capacitance retention after 10,000 cycles, thus meeting the demands for large-scale applications such as trolleybuses.

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.

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.

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…

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

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.

Single and multi-frequency impedance characterization of symmetric activated carbon single capacitor cells

Directory of Open Access Journals (Sweden)

Suzana Sopčić

2018-05-01

Full Text Available Electrochemical impedance spectroscopy (EIS technique is used for characterization of single cell symmetric capacitors having different mass loadings of activated carbon (AC. Relevant values of charge storage capacitance (CT and internal resistance (ESR were evaluated by the single frequency and multi-frequency analyses of measured impedance spectra. Curve fittings were based on the non-ideal R-C model that takes into account the parasitic inductance, contributions from electrode materials/contacts and the effects of AC porosity. Higher CT and lower ESR values were obtained not only for the cell with higher mass of AC, but also using the single vs. multi-frequency approach. Lower CT and higher values of ESR that are generally obtained using the multi-frequency method and curve fittings should be related to the not ideal capacitive response of porous AC material and too high frequency chosen in applying the single frequency analysis.

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.

Neural coding in antennal olfactory cells of tsetse flies (Glossina spp.)

NARCIS (Netherlands)

Voskamp, K.E; Noorman, N; Mastebroek, H.A K; van Schoot, N.E.G.; den Otter, C.J

1998-01-01

Spike trains from individual antennal olfactory cells of tsetse flies (Glossina spp.) obtained during steady-state conditions (spontaneous as well as during stimulation with 1-octen-3-ol) and dynamic stimulation with repetitive pulses of 1-octen-3-ol were investigated by studying the spike frequency

Soluble components of the flagellar export apparatus, FliI, FliJ, and FliH, do not deliver flagellin, the major filament protein, from the cytosol to the export gate.

Science.gov (United States)

Sajó, Ráchel; Liliom, Károly; Muskotál, Adél; Klein, Agnes; Závodszky, Péter; Vonderviszt, Ferenc; Dobó, József

2014-11-01

Flagella, the locomotion organelles of bacteria, extend from the cytoplasm to the cell exterior. External flagellar proteins are synthesized in the cytoplasm and exported by the flagellar type III secretion system. Soluble components of the flagellar export apparatus, FliI, FliH, and FliJ, have been implicated to carry late export substrates in complex with their cognate chaperones from the cytoplasm to the export gate. The importance of the soluble components in the delivery of the three minor late substrates FlgK, FlgL (hook-filament junction) and FliD (filament-cap) has been convincingly demonstrated, but their role in the transport of the major filament component flagellin (FliC) is still unclear. We have used continuous ATPase activity measurements and quartz crystal microbalance (QCM) studies to characterize interactions between the soluble export components and flagellin or the FliC:FliS substrate-chaperone complex. As controls, interactions between soluble export component pairs were characterized providing Kd values. FliC or FliC:FliS did not influence the ATPase activity of FliI alone or in complex with FliH and/or FliJ suggesting lack of interaction in solution. Immobilized FliI, FliH, or FliJ did not interact with FliC or FliC:FliS detected by QCM. The lack of interaction in the fluid phase between FliC or FliC:FliS and the soluble export components, in particular with the ATPase FliI, suggests that cells use different mechanisms for the export of late minor substrates, and the major substrate, FliC. It seems that the abundantly produced flagellin does not require the assistance of the soluble export components to efficiently reach the export gate. Copyright © 2014 Elsevier B.V. All rights reserved.

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

FLI1 Expression in Breast Cancer Cell Lines and Primary Breast Carcinomas is Correlated with ER, PR and HER2

Directory of Open Access Journals (Sweden)

Inam Jasim Lafta

2017-12-01

Full Text Available FLI1 is a member of ETS family of transcription factors that regulate a variety of normal biologic activities including cell proliferation, differentiation, and apoptosis. The expression of FLI1 and its correlation with well-known breast cancer prognostic markers (ER, PR and HER2 was determined in primary breast tumors as well as four breast cancer lines including: MCF-7, T47D, MDA-MB-231 and MDA-MB-468 using RT-qPCR with either 18S rRNA or ACTB (β-actin for normalization of data. FLI1 mRNA level was decreased in the breast cancer cell lines under study compared to the normal breast tissue; however, Jurkat cells, which were used as a positive control, showed overexpression compared to the normal breast. Regarding primary breast carcinomas, FLI1 is significantly under expressed in all of the stages of breast cancer upon using 18S as an internal control. This FLI1 expression was correlated with ER, PR and HER2 status. In conclusion FLI1 can be exploited as a preliminary marker that can predict the status of ER, PR and HER2 in primary breast tumors.

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.

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.

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)

Analysis and Design of a Bidirectional Isolated DC-DC Converter for Fuel Cell and Super-Capacitor Hybrid System

DEFF Research Database (Denmark)

Zhang, Zhe; Ouyang, Ziwei; Thomsen, Ole Cornelius

2012-01-01

Electrical power system in future uninterruptible power supply (UPS) or electrical vehicle (EV) may employ hybrid energy sources, such as fuel cells and super-capacitors. It will be necessary to efficiently draw the energy from these two sources as well as recharge the energy storage elements...... by the DC bus. In this paper, a bidirectional isolated DC-DC converter controlled by phase-shift and duty cycle for the fuel cell hybrid energy system is analyzed and designed. The proposed topology minimizes the number of switches and their associated gate driver components by using two high frequency...

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.

Generalized Multi-Cell Switched-Inductor and Switched-Capacitor Z-source Inverters

DEFF Research Database (Denmark)

Li, Ding; Chiang Loh, Poh; Zhu, Miao

2013-01-01

. Their boosting gains are, therefore, limited in practice. To overcome these shortcomings, the generalized switched-inductor and switched-capacitor Z-source inverters are proposed, whose extra boosting abilities and other advantages have already been verified in simulation and experiment....

Fuel cell/electrochemical capacitor hybrid for intermittent high power applications

Energy Technology Data Exchange (ETDEWEB)

Jarvis, L P; Atwater, T B; Cygan, P J [Army Communications-Electronics Command (CECOM), Fort Monmouth, NJ (United States). Research and Development Center

1999-05-01

A hybrid power source was demonstrated to successfully power a simulated power load encountered in portable military electronics and communications equipment. The hybrid system consisted of a 25 W proton exchange membrane fuel cell (PEMFC) stack connected in parallel with a 70 F capacitor bank. The cyclic regime of 18.0 W for 2 min followed by 2.5 W for 18 min was chosen as the baseline for the simulation of power load. The operating potential cut-off voltage for pass/failure was set to 3.0 V. At room temperature (23-25 C), the PEMFC alone could not handle the described baseline regime with the PEMFC operating potential dropping below the cut-off voltage within 10 s. The hybrid, however, continuously powered the same regime for 25 h. Its operating potential never reached the voltage cut-off point, not even during the high load of 18.0 W. The tests with hybrid configuration were aborted after 25 h of operation with no signs of output degradation, suggesting that further extended operation was possible. (orig.)

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...

Anti-oxidative and inflammatory responses induced by fly ash particles and carbon black in lung epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Diabate, Silvia; Plaumann, Diana; Uebel, Caroline; Weiss, Carsten [Karlsruhe Institute of Technology, Institute of Toxicology and Genetics, Eggenstein-Leopoldshafen (Germany); Bergfeldt, Britta [Karlsruhe Institute of Technology, Institute of Technical Chemistry, Eggenstein-Leopoldshafen (Germany)

2011-12-15

Combustion-derived nanoparticles as constituents of ambient particulate matter have been shown to induce adverse health effects due to inhalation. However, the components inducing these effects as well as the biological mechanisms are still not fully understood. The fine fraction of fly ash particles collected from the electrostatic precipitator of a municipal solid waste incinerator was taken as an example for real particles with complex composition released into the atmosphere to study the mechanism of early biological responses of BEAS-2B human lung epithelial cells. The studies include the effects of the water-soluble and -insoluble fractions of the fly ash and the well-studied carbon black nanoparticles were used as a reference. Fly ash induced reactive oxygen species (ROS) and increased the total cellular glutathione (tGSH) content. Carbon black also induced ROS generation; however, in contrast to the fly ash, it decreased the intracellular tGSH. The fly ash-induced oxidative stress was correlated with induction of the anti-oxidant enzyme heme oxygenase-1 and increase of the redox-sensitive transcription factor Nrf2. Carbon black was not able to induce HO-1. ROS generation, tGSH increase and HO-1 induction were only induced by the insoluble fraction of the fly ash, not by the water-soluble fraction. ROS generation and HO-1 induction were markedly inhibited by pre-incubation of the cells with the anti-oxidant N-acetyl cysteine which confirmed the involvement of oxidative stress. Both effects were also reduced by the metal chelator deferoxamine indicating a contribution of bioavailable transition metals. In summary, both fly ash and carbon black induce ROS but only fly ash induced an increase of intracellular tGSH and HO-1 production. Bioavailable transition metals in the solid water-insoluble matrix of the fly ash mostly contribute to the effects. (orig.)

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

Molecular dissection of the mechanism by which EWS/FLI expression compromises actin cytoskeletal integrity and cell adhesion in Ewing sarcoma

Science.gov (United States)

Chaturvedi, Aashi; Hoffman, Laura M.; Jensen, Christopher C.; Lin, Yi-Chun; Grossmann, Allie H.; Randall, R. Lor; Lessnick, Stephen L.; Welm, Alana L.; Beckerle, Mary C.

2014-01-01

Ewing sarcoma is the second-most-common bone cancer in children. Driven by an oncogenic chromosomal translocation that results in the expression of an aberrant transcription factor, EWS/FLI, the disease is typically aggressive and micrometastatic upon presentation. Silencing of EWS/FLI in patient-derived tumor cells results in the altered expression of hundreds to thousands of genes and is accompanied by dramatic morphological changes in cytoarchitecture and adhesion. Genes encoding focal adhesion, extracellular matrix, and actin regulatory proteins are dominant targets of EWS/FLI-mediated transcriptional repression. Reexpression of genes encoding just two of these proteins, zyxin and α5 integrin, is sufficient to restore cell adhesion and actin cytoskeletal integrity comparable to what is observed when the EWS/FLI oncogene expression is compromised. Using an orthotopic xenograft model, we show that EWS/FLI-induced repression of α5 integrin and zyxin expression promotes tumor progression by supporting anchorage-independent cell growth. This selective advantage is paired with a tradeoff in which metastatic lung colonization is compromised. PMID:25057021

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

Hybrid Lithium-ion Capacitor / Lithium-ion Battery System for Extended Performance

Data.gov (United States)

National Aeronautics and Space Administration — The proposed task will involve the design of a hybrid power system with lithium-ion (li-ion) capacitors (LICs), li-ion batteries and solar cells. The challenge in...

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

Small-molecule screen identifies modulators of EWS/FLI1 target gene expression and cell survival in Ewing's sarcoma.

Science.gov (United States)

Boro, Aleksandar; Prêtre, Kathya; Rechfeld, Florian; Thalhammer, Verena; Oesch, Susanne; Wachtel, Marco; Schäfer, Beat W; Niggli, Felix K

2012-11-01

Ewing's sarcoma family of tumors (EFT) is characterized by the presence of chromosomal translocations leading to the expression of oncogenic transcription factors such as, in the majority of cases, EWS/FLI1. Because of its key role in Ewing's sarcoma development and maintenance, EWS/FLI1 represents an attractive therapeutic target. Here, we characterize PHLDA1 as a novel direct target gene whose expression is repressed by EWS/FLI1. Using this gene and additional specific well-characterized target genes such as NROB1, NKX2.2 and CAV1, all activated by EWS/FLI1, as a read-out system, we screened a small-molecule compound library enriched for FDA-approved drugs that modulated the expression of EWS/FLI1 target genes. Among a hit-list of nine well-known drugs such as camptothecin, fenretinide, etoposide and doxorubicin, we also identified the kinase inhibitor midostaurin (PKC412). Subsequent experiments demonstrated that midostaurin is able to induce apoptosis in a panel of six Ewing's sarcoma cell lines in vitro and can significantly suppress xenograft tumor growth in vivo. These results suggest that midostaurin might be a novel drug that is active against Ewing's cells, which might act by modulating the expression of EWS/FLI1 target genes. Copyright © 2012 UICC.

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.

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.

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

Alternate charging and discharging of capacitor to enhance the electron production of bioelectrochemical systems.

Science.gov (United States)

Liang, Peng; Wu, Wenlong; Wei, Jincheng; Yuan, Lulu; Xia, Xue; Huang, Xia

2011-08-01

A bioelectrochemical system (BES) can be operated in both "microbial fuel cell" (MFC) and "microbial electrolysis cell" (MEC) modes, in which power is delivered and invested respectively. To enhance the electric current production, a BES was operated in MFC mode first and a capacitor was used to collect power from the system. Then the charged capacitor discharged electrons to the system itself, switching into MEC mode. This alternate charging and discharging (ACD) mode helped the system produce 22-32% higher average current compared to an intermittent charging (IC) mode, in which the capacitor was first charged from an MFC and then discharged to a resistor, at 21.6 Ω external resistance, 3.3 F capacitance and 300 mV charging voltage. The effects of external resistance, capacitance and charging voltage on average current were studied. The average current reduced as the external resistance and charging voltage increased and was slightly affected by the capacitance. Acquisition of higher average current in the ACD mode was attributed to the shorter discharging time compared to the charging time, as well as a higher anode potential caused by discharging the capacitor. Results from circuit analysis and quantitatively calculation were consistent with the experimental observations.

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.

Flies without centrioles.

Science.gov (United States)

Basto, Renata; Lau, Joyce; Vinogradova, Tatiana; Gardiol, Alejandra; Woods, C Geoffrey; Khodjakov, Alexey; Raff, Jordan W

2006-06-30

Centrioles and centrosomes have an important role in animal cell organization, but it is uncertain to what extent they are essential for animal development. The Drosophila protein DSas-4 is related to the human microcephaly protein CenpJ and the C. elegans centriolar protein Sas-4. We show that DSas-4 is essential for centriole replication in flies. DSas-4 mutants start to lose centrioles during embryonic development, and, by third-instar larval stages, no centrioles or centrosomes are detectable. Mitotic spindle assembly is slow in mutant cells, and approximately 30% of the asymmetric divisions of larval neuroblasts are abnormal. Nevertheless, mutant flies develop with near normal timing into morphologically normal adults. These flies, however, have no cilia or flagella and die shortly after birth because their sensory neurons lack cilia. Thus, centrioles are essential for the formation of centrosomes, cilia, and flagella, but, remarkably, they are not essential for most aspects of Drosophila development.

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.

Impact of frequency modulation ratio on capacitor cells balancing in phase-shifted PWM based chain-link STATCOM

DEFF Research Database (Denmark)

Behrouzian, Ehsan; Bongiorno, Massimo; Teodorescu, Remus

2014-01-01

to provide more uniform power distribution among the cells, two different methods called, a) carrier swapping and b) non-integer frequency modulation ratio are studied. In particular, it is shown that the selection of a non-integer frequency modulation ratio helps in providing a more uniform power......The purpose of this paper is to investigate the impact of switching harmonics on the instantaneous power that flows in the cells of a chain-link based STATCOM when using Phase-Shifted PWM. Two different cases are investigated for the converter cells: low, and high switching frequency. It is shown...... that any deviation from the ideal conditions lead to undesired harmonics, which will impact the charge of the dc capacitors. It is also shown that for low switching frequencies, cells voltage sideband harmonics interact with baseband harmonics of the current and causes extra source of unbalance. In order...

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.

CD4+ T cell epitopes of FliC conserved between strains of Burkholderia: implications for vaccines against melioidosis and cepacia complex in cystic fibrosis.

Science.gov (United States)

Musson, Julie A; Reynolds, Catherine J; Rinchai, Darawan; Nithichanon, Arnone; Khaenam, Prasong; Favry, Emmanuel; Spink, Natasha; Chu, Karen K Y; De Soyza, Anthony; Bancroft, Gregory J; Lertmemongkolchai, Ganjana; Maillere, Bernard; Boyton, Rosemary J; Altmann, Daniel M; Robinson, John H

2014-12-15

Burkholderia pseudomallei is the causative agent of melioidosis characterized by pneumonia and fatal septicemia and prevalent in Southeast Asia. Related Burkholderia species are strong risk factors of mortality in cystic fibrosis (CF). The B. pseudomallei flagellar protein FliC is strongly seroreactive and vaccination protects challenged mice. We assessed B. pseudomallei FliC peptide binding affinity to multiple HLA class II alleles and then assessed CD4 T cell immunity in HLA class II transgenic mice and in seropositive individuals in Thailand. T cell hybridomas were generated to investigate cross-reactivity between B. pseudomallei and the related Burkholderia species associated with Cepacia Complex CF. B. pseudomallei FliC contained several peptide sequences with ability to bind multiple HLA class II alleles. Several peptides were shown to encompass strong CD4 T cell epitopes in B. pseudomallei-exposed individuals and in HLA transgenic mice. In particular, the p38 epitope is robustly recognized by CD4 T cells of seropositive donors across diverse HLA haplotypes. T cell hybridomas against an immunogenic B. pseudomallei FliC epitope also cross-reacted with orthologous FliC sequences from Burkholderia multivorans and Burkholderia cenocepacia, important pathogens in CF. Epitopes within FliC were accessible for processing and presentation from live or heat-killed bacteria, demonstrating that flagellin enters the HLA class II Ag presentation pathway during infection of macrophages with B. cenocepacia. Collectively, the data support the possibility of incorporating FliC T cell epitopes into vaccination programs targeting both at-risk individuals in B. pseudomallei endemic regions as well as CF patients. Copyright © 2014 by The American Association of Immunologists, Inc.

Activity of Proteus mirabilis FliL is viscosity dependent and requires extragenic DNA.

Science.gov (United States)

Lee, Yi-Ying; Patellis, Julius; Belas, Robert

2013-02-01

Proteus mirabilis is a urinary tract pathogen and well known for its ability to move over agar surfaces by flagellum-dependent swarming motility. When P. mirabilis encounters a highly viscous environment, e.g., an agar surface, it differentiates from short rods with few flagella to elongated, highly flagellated cells that lack septa and contain multiple nucleoids. The bacteria detect a surface by monitoring the rotation of their flagellar motors. This process involves an enigmatic flagellar protein called FliL, the first gene in an operon (fliLMNOPQR) that encodes proteins of the flagellar rotor switch complex and flagellar export apparatus. We used a fliL knockout mutant to gain further insight into the function of FliL. Loss of FliL results in cells that cannot swarm (Swr(-)) but do swim (Swm(+)) and produces cells that look like wild-type swarmer cells, termed "pseudoswarmer cells," that are elongated, contain multiple nucleoids, and lack septa. Unlike swarmer cells, pseudoswarmer cells are not hyperflagellated due to reduced expression of flaA (the gene encoding flagellin), despite an increased transcription of both flhD and fliA, two positive regulators of flagellar gene expression. We found that defects in fliL prevent viscosity-dependent sensing of a surface and viscosity-dependent induction of flaA transcription. Studies with fliL cells unexpectedly revealed that the fliL promoter, fliL coding region, and a portion of fliM DNA are needed to complement the Swr(-) phenotype. The data support a dual role for FliL as a critical link in sensing a surface and in the maintenance of flagellar rod integrity.

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.

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.

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).

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

High speed capacitor-inverter based carbon nanotube full adder.

Science.gov (United States)

Navi, K; Rashtian, M; Khatir, A; Keshavarzian, P; Hashemipour, O

2010-03-18

Carbon Nanotube filed-effect transistor (CNFET) is one of the promising alternatives to the MOS transistors. The geometry-dependent threshold voltage is one of the CNFET characteristics, which is used in the proposed Full Adder cell. In this paper, we present a high speed Full Adder cell using CNFETs based on majority-not (Minority) function. Presented design uses eight transistors and eight capacitors. Simulation results show significant improvement in terms of delay and power-delay product in comparison to contemporary CNFET Adder Cells. Simulations were carried out using HSPICE based on CNFET model with 0.6 V VDD.

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

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.

Loss of FliL alters Proteus mirabilis surface sensing and temperature-dependent swarming.

Science.gov (United States)

Lee, Yi-Ying; Belas, Robert

2015-01-01

Proteus mirabilis is a dimorphic motile bacterium well known for its flagellum-dependent swarming motility over surfaces. In liquid, P. mirabilis cells are 1.5- to 2.0-μm swimmer cells with 4 to 6 flagella. When P. mirabilis encounters a solid surface, where flagellar rotation is limited, swimmer cells differentiate into elongated (10- to 80-μm), highly flagellated swarmer cells. In order for P. mirabilis to swarm, it first needs to detect a surface. The ubiquitous but functionally enigmatic flagellar basal body protein FliL is involved in P. mirabilis surface sensing. Previous studies have suggested that FliL is essential for swarming through its involvement in viscosity-dependent monitoring of flagellar rotation. In this study, we constructed and characterized ΔfliL mutants of P. mirabilis and Escherichia coli. Unexpectedly and unlike other fliL mutants, both P. mirabilis and E. coli ΔfliL cells swarm (Swr(+)). Further analysis revealed that P. mirabilis ΔfliL cells also exhibit an alteration in their ability to sense a surface: e.g., ΔfliL P. mirabilis cells swarm precociously over surfaces with low viscosity that normally impede wild-type swarming. Precocious swarming is due to an increase in the number of elongated swarmer cells in the population. Loss of fliL also results in an inhibition of swarming at <30°C. E. coli ΔfliL cells also exhibit temperature-sensitive swarming. These results suggest an involvement of FliL in the energetics and function of the flagellar motor. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Acetylation Increases EWS-FLI1 DNA Binding and Transcriptional Activity

International Nuclear Information System (INIS)

Schlottmann, Silke; Erkizan, Hayriye V.; Barber-Rotenberg, Julie S.; Knights, Chad; Cheema, Amrita; Üren, Aykut; Avantaggiati, Maria L.; Toretsky, Jeffrey A.

2012-01-01

Ewing Sarcoma (ES) is associated with a balanced chromosomal translocation that in most cases leads to the expression of the oncogenic fusion protein and transcription factor EWS-FLI1. EWS-FLI1 has been shown to be crucial for ES cell survival and tumor growth. However, its regulation is still enigmatic. To date, no functionally significant post-translational modifications of EWS-FLI1 have been shown. Since ES are sensitive to histone deacetylase inhibitors (HDI), and these inhibitors are advancing in clinical trials, we sought to identify if EWS-FLI1 is directly acetylated. We convincingly show acetylation of the C-terminal FLI1 (FLI1-CTD) domain, which is the DNA binding domain of EWS-FLI1. In vitro acetylation studies showed that acetylated FLI1-CTD has higher DNA binding activity than the non-acetylated protein. Over-expression of PCAF or treatment with HDI increased the transcriptional activity of EWS-FLI1, when co-expressed in Cos7 cells. However, our data that evaluates the acetylation of full-length EWS-FLI1 in ES cells remains unclear, despite creating acetylation specific antibodies to four potential acetylation sites. We conclude that EWS-FLI1 may either gain access to chromatin as a result of histone acetylation or undergo regulation by direct acetylation. These data should be considered when patients are treated with HDAC inhibitors. Further investigation of this phenomenon will reveal if this potential acetylation has an impact on tumor response.

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.

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

Light sensitivity of a one transistor-one capacitor memory cell when used as a micromirror actuator in projector applications

Science.gov (United States)

Huffman, James Douglas

2001-11-01

The most important issue facing the future business success of the Digital Micromirror Device or DMD™ produced by Texas Instruments is the cost of the actual device. As the business and consumer markets call for higher resolution displays, the array size will have to be increased to incorporate more pixels. The manufacturing costs associated with building these higher resolution displays follow an exponential relation with the number of pixels due to yield loss and reduced number of chips per silicon wafer. Each pixel is actuated by electrostatics that are provided by a memory cell that is built in the underlying silicon substrate. One way to decrease cost of the wafer is to change the memory cell architecture from a static random access configuration or SRAM to a dynamic random access configuration or DRAM. This change has the benefits of having fewer components per area and a lower metal density. This reduction in the component count and metal density has a dramatic effect on the yield of the memory array by reducing the particle sensitivity of the underlying cell. The main drawback to using a DRAM configuration in a display application is the light sensitivity of a charge storage device built in the silicon substrate. As the photons pass through the mechanical micromirrors and illuminate the DRAM cell, the effective electrostatic potential of the memory element used for the mirror actuation is reduced. This dissertation outlines the issues associated with the light sensitivity of a DRAM memory cell as the actuation element for a micromirror. The concept of charge depletion on a silicon capacitor due to recombination of photogenerated carriers is explored and experimentally verified. The effects of the reduced potential on the capacitor on the micromirror are also explored. Optical modeling is used to determine the incoming photon flux to determine the benefits of adding a charge recombination region as part of the DRAM memory cell. Several options are explored

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.

High voltage AC/AC electrochemical capacitor operating at low temperature in salt aqueous electrolyte

Science.gov (United States)

Abbas, Qamar; Béguin, François

2016-06-01

We demonstrate that an activated carbon (AC)-based electrochemical capacitor implementing aqueous lithium sulfate electrolyte in 7:3 vol:vol water/methanol mixture can operate down to -40 °C with good electrochemical performance. Three-electrode cell investigations show that the faradaic contributions related with hydrogen chemisorption in the negative AC electrode are thermodynamically unfavored at -40 °C, enabling the system to work as a typical electrical double-layer (EDL) capacitor. After prolonged floating of the AC/AC capacitor at 1.6 V and -40°C, the capacitance, equivalent series resistance and efficiency remain constant, demonstrating the absence of ageing related with side redox reactions at this temperature. Interestingly, when temperature is increased back to 24 °C, the redox behavior due to hydrogen storage reappears and the system behaves as a freshly prepared one.

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)

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....

Regulatory arrestin cycle secures the fidelity and maintenance of the fly photoreceptor cell.

Science.gov (United States)

Byk, T; Bar-Yaacov, M; Doza, Y N; Minke, B; Selinger, Z

1993-01-01

Excitation of fly photoreceptor cells is initiated by photoisomerization of rhodopsin to the active form of metarhodopsin. Fly metarhodopsin is thermostable, does not bleach, and does not regenerate spontaneously to rhodopsin. For this reason, the activity of metarhodopsin must be stopped by an effective termination reaction. On the other hand, there is also a need to restore the inactivated photopigment to an excitable state in order to keep a sufficient number of photopigment molecules available for excitation. The following findings reveal how these demands are met. The photopigment undergoes rapid phosphorylation upon photoconversion of rhodopsin to metarhodopsin and an efficient Ca2+ dependent dephosphorylation upon regeneration of metarhodopsin to rhodopsin. Phosphorylation decreases the ability of metarhodopsin to activate the guanine nucleotide-binding protein. Binding of 49-kDa arrestin further quenches the activity of metarhodopsin and protects it from dephosphorylation. Light-dependent binding and release of 49-kDa arrestin from metarhodopsin- and rhodopsin-containing membranes, respectively, directs the dephosphorylation reaction toward rhodopsin. This ensures the return of phosphorylated metarhodopsin to the rhodopsin pool without initiating transduction in the dark. Assays of rhodopsin dephosphorylation in the Drosophila retinal degeneration C (rdgC) mutant, a mutant in a gene previously cloned and predicted to encode a serine/threonine protein phosphatase, reveal that phosphorylated rhodopsin is a major substrate for the rdgC phosphatase. We propose that mutations resulting in either a decrease or an improper regulation of rhodopsin phosphatase activity bring about degeneration of the fly photoreceptor cells. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8446607

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.

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.

Importance of Campylobacter jejuni FliS and FliW in Flagella Biogenesis and Flagellin Secretion

Directory of Open Access Journals (Sweden)

Katarzyna A. Radomska

2017-06-01

Full Text Available Flagella-driven motility enables bacteria to reach their favorable niche within the host. The human foodborne pathogen Campylobacter jejuni produces two heavily glycosylated structural flagellins (FlaA and FlaB that form the flagellar filament. It also encodes the non-structural FlaC flagellin which is secreted through the flagellum and has been implicated in host cell invasion. The mechanisms that regulate C. jejuni flagellin biogenesis and guide the proteins to the export apparatus are different from those in most other enteropathogens and are not fully understood. This work demonstrates the importance of the putative flagellar protein FliS in C. jejuni flagella assembly. A constructed fliS knockout strain was non-motile, displayed reduced levels of FlaA/B and FlaC flagellin, and carried severely truncated flagella. Pull-down and Far Western blot assays showed direct interaction of FliS with all three C. jejuni flagellins (FlaA, FlaB, and FlaC. This is in contrast to, the sensor and regulator of intracellular flagellin levels, FliW, which bound to FlaA and FlaB but not to FlaC. The FliS protein but not FliW preferred binding to glycosylated C. jejuni flagellins rather than to their non-glycosylated recombinant counterparts. Mapping of the binding region of FliS and FliW using a set of flagellin fragments showed that the C-terminal subdomain of the flagellin was required for FliS binding, whereas the N-terminal subdomain was essential for FliW binding. The separate binding subdomains required for FliS and FliW, the different substrate specificity, and the differential preference for binding of glycosylated flagellins ensure optimal processing and assembly of the C. jejuni flagellins.

Hybrid capacitors utilizing halogen-based redox reactions at interface between carbon positive electrode and aqueous electrolytes

Science.gov (United States)

Yamazaki, Shigeaki; Ito, Tatsuya; Murakumo, Yuka; Naitou, Masashi; Shimooka, Toshiharu; Yamagata, Masaki; Ishikawa, Masashi

2016-09-01

We propose novel hybrid capacitors (HCs) with electrolyte-involved redox reactions of bromide or iodide species by pretreatment of an activated carbon positive electrode. The treatment is simple; impregnation of pores at an activated carbon fiber cloth (ACFC) as a positive electrode with bromine- or iodine-containing water before cell assembly. The treated positive electrode is applied to a HC cell with a non-treated negative electrode of ACFC and its electrochemical performance is investigated by galvanostatic cycling and leakage current tests. Few studies on such "electrolytic" charge storage systems have provided acceptable capacitor performance because of inevitable self-discharge caused by diffusion of charged species form an electrode to the other one through an electrolyte. Nevertheless, our electrolyte-redox-based HCs show excellent performance without undesirable diffusion of charged species. Moreover, the present HC utilizing a bromide redox system fulfills a practical cell voltage of 1.8 V in spite of an aqueous electrolyte system. This high voltage provides excellent energy density, which is 5 times higher than that in a conventional aqueous electric double-layer capacitor (EDLC), and 1.2 times higher even than that in a 2.7 V-class non-aqueous EDLC, while keeping high charge-discharge rate capability.

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

A Novel Approach to Inspect Abnormalities on the Deep Trench Capacitors in DRAM

Science.gov (United States)

Liu, H. W.; Cheng, E.; Lin, Y. M.; Fan, S.; Pan, K.; Lue, J. L.

2005-09-01

A novel method has been developed using Focused Ion Beam (FIB) system to create the likely three-dimensional (3D) image of a deep trench (DT) capacitor in a DRAM cell for process evaluation and failure analysis. The abnormalities in the structures of DT capacitors, especially "DT striation" and "DT-DT short", result in the functional failures or retention problems detected in the electrical test, which are very common failures in a DT capacitor DRAM cell. The common method to examine failed DTs is to use FIB milling with its slice-and-view capability for both planar and cross-sectional observations. However, the areas containing the defects in the specific DTs are probably milled away during FIB milling, so that the failure causes could not be found. The new method uses XeF2 etching gas to reveal the likely 3D appearance of the desired DTs, instead of the traditional FIB slice-and-view method. The abnormalities on the structures of the specific DTs can then be inspected using Scanning Electron Microscopy (SEM). The innovation of this technique not only provides more information on the desired DTs, but also provides a quick way to identify the possible causes for the failures. In summary, this method will provide an effective way to improve the success rate and turnaround time for the inspection of failed DTs.

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.

Carbon-Based Materials for Lithium-Ion Batteries, Electrochemical Capacitors, and Their Hybrid Devices.

Science.gov (United States)

Yao, Fei; Pham, Duy Tho; Lee, Young Hee

2015-07-20

A rapidly developing market for portable electronic devices and hybrid electrical vehicles requires an urgent supply of mature energy-storage systems. As a result, lithium-ion batteries and electrochemical capacitors have lately attracted broad attention. Nevertheless, it is well known that both devices have their own drawbacks. With the fast development of nanoscience and nanotechnology, various structures and materials have been proposed to overcome the deficiencies of both devices to improve their electrochemical performance further. In this Review, electrochemical storage mechanisms based on carbon materials for both lithium-ion batteries and electrochemical capacitors are introduced. Non-faradic processes (electric double-layer capacitance) and faradic reactions (pseudocapacitance and intercalation) are generally explained. Electrochemical performance based on different types of electrolytes is briefly reviewed. Furthermore, impedance behavior based on Nyquist plots is discussed. We demonstrate the influence of cell conductivity, electrode/electrolyte interface, and ion diffusion on impedance performance. We illustrate that relaxation time, which is closely related to ion diffusion, can be extracted from Nyquist plots and compared between lithium-ion batteries and electrochemical capacitors. Finally, recent progress in the design of anodes for lithium-ion batteries, electrochemical capacitors, and their hybrid devices based on carbonaceous materials are reviewed. Challenges and future perspectives are further discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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)

Digital multimeter-based immunosensing strategy for sensitive monitoring of biomarker by coupling an external capacitor with an enzymatic catalysis.

Science.gov (United States)

Tang, Dianping; Zhang, Bing; Liu, Bingqian; Chen, Guonan; Lu, Minghua

2014-05-15

A new digital multimeter (DMM)-based immunosensing system was designed for quantitative monitoring of biomarker (prostate-specific antigen, PSA used in this case) by coupling with an external capacitor and an enzymatic catalytic reaction. The system consisted of a salt bridge-linked reaction cell and a capacitor/DMM-joined electronic circuit. A sandwich-type immunoreaction with target PSA between the immobilized primary antibody and glucose oxidase (GOx)-labeled detection antibody was initially carried out in one of the two half-cells. Accompanying the sandwiched immunocomplex, the conjugated GOx could catalyze the oxidation of glucose, simultaneously resulting in the conversion of [Fe(CN)6](3-) to [Fe(CN)6](4-). The difference in the concentrations of [Fe(CN)6](3-)/[Fe(CN)6](4-) in two half-cells automatically produced a voltage that was utilized to charge an external capacitor. With the closing circuit switch, the capacitor discharged through the DMM, which could provide a high instantaneous current. Under the optimal conditions, the resulting currents was indirectly proportional to the concentration of target PSA in the dynamic range of 0.05-7 ng mL(-1) with a detection limit (LOD) of 6 pg mL(-1). The reproducibility, precision, and selectivity were acceptable. In addition, the methodology was validated by analyzing 12 clinical serum specimens, receiving a good accordance with the referenced values for the detection of PSA. Copyright © 2013 Elsevier B.V. All rights reserved.

MgO-templated carbon as a negative electrode material for Na-ion capacitors

Science.gov (United States)

Kado, Yuya; Soneda, Yasushi

2016-12-01

In this study, MgO-templated carbon with different pore structures was investigated as a negative electrode material for Na-ion capacitors. With increasing the Brunauer-Emmett-Teller surface area, the irreversible capacity increased, and the coulombic efficiency of the 1st cycle decreased because of the formation of solid electrolyte interface layers. MgO-templated carbon annealed at 1000 °C exhibited the highest capacity and best rate performance, suggesting that an appropriate balance between surface area and crystallinity is imperative for fast Na-ion storage, attributed to the storage mechanism: combination of non-faradaic electric double-layer capacitance and faradaic Na intercalation in the carbon layers. Finally, a Na-ion capacitor cell using MgO-templated carbon and activated carbon as the negative and positive electrodes, respectively, exhibited an energy density at high power density significantly greater than that exhibited by the cell using a commercial hard carbon negative electrode.

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...

Inhibition of the oncogenic fusion protein EWS-FLI1 causes G2-M cell cycle arrest and enhanced vincristine sensitivity in Ewing's sarcoma.

Science.gov (United States)

Zöllner, Stefan K; Selvanathan, Saravana P; Graham, Garrett T; Commins, Ryan M T; Hong, Sung Hyeok; Moseley, Eric; Parks, Sydney; Haladyna, Jessica N; Erkizan, Hayriye V; Dirksen, Uta; Hogarty, Michael D; Üren, Aykut; Toretsky, Jeffrey A

2017-10-03

Ewing's sarcoma (ES) is a rare and highly malignant cancer that grows in the bones or surrounding tissues mostly affecting adolescents and young adults. A chimeric fusion between the RNA binding protein EWS and the ETS family transcription factor FLI1 (EWS-FLI1), which is generated from a chromosomal translocation, is implicated in driving most ES cases by modulation of transcription and alternative splicing. The small-molecule YK-4-279 inhibits EWS-FLI1 function and induces apoptosis in ES cells. We aimed to identify both the underlying mechanism of the drug and potential combination therapies that might enhance its antitumor activity. We tested 69 anticancer drugs in combination with YK-4-279 and found that vinca alkaloids exhibited synergy with YK-4-279 in five ES cell lines. The combination of YK-4-279 and vincristine reduced tumor burden and increased survival in mice bearing ES xenografts. We determined that independent drug-induced events converged to cause this synergistic therapeutic effect. YK-4-279 rapidly induced G 2 -M arrest, increased the abundance of cyclin B1, and decreased EWS-FLI1-mediated generation of microtubule-associated proteins, which rendered cells more susceptible to microtubule depolymerization by vincristine. YK-4-279 reduced the expression of the EWS-FLI1 target gene encoding the ubiquitin ligase UBE2C, which, in part, contributed to the increase in cyclin B1. YK-4-279 also increased the abundance of proapoptotic isoforms of MCL1 and BCL2, presumably through inhibition of alternative splicing by EWS-FLI1, thus promoting cell death in response to vincristine. Thus, a combination of vincristine and YK-4-279 might be therapeutically effective in ES patients. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

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…

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.

Highly Oriented Graphene Sponge Electrode for Ultra High Energy Density Lithium Ion Hybrid Capacitors.

Science.gov (United States)

Ahn, Wook; Lee, Dong Un; Li, Ge; Feng, Kun; Wang, Xiaolei; Yu, Aiping; Lui, Gregory; Chen, Zhongwei

2016-09-28

Highly oriented rGO sponge (HOG) can be easily synthesized as an effective anode for application in high-capacity lithium ion hybrid capacitors. X-ray diffraction and morphological analyses show that successfully exfoliated rGO sponge on average consists of 4.2 graphene sheets, maintaining its three-dimensional structure with highly oriented morphology even after the thermal reduction procedure. Lithium-ion hybrid capacitors (LIC) are fabricated in this study based on a unique cell configuration which completely eliminates the predoping process of lithium ions. The full-cell LIC consisting of AC/HOG-Li configuration has resulted in remarkably high energy densities of 231.7 and 131.9 Wh kg(-1) obtained at 57 W kg(-1) and 2.8 kW kg(-1). This excellent performance is attributed to the lithium ion diffusivity related to the intercalation reaction of AC/HOG-Li which is 3.6 times higher that of AC/CG-Li. This unique cell design and configuration of LIC presented in this study using HOG as an effective anode is an unprecedented example of performance enhancement and improved energy density of LIC through successful increase in cell operation voltage window.

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

Scalable integration of Li5FeO4 towards robust, high-performance lithium-ion hybrid capacitors.

Science.gov (United States)

Park, Min-Sik; Lim, Young-Geun; Hwang, Soo Min; Kim, Jung Ho; Kim, Jeom-Soo; Dou, Shi Xue; Cho, Jaephil; Kim, Young-Jun

2014-11-01

Lithium-ion hybrid capacitors have attracted great interest due to their high specific energy relative to conventional electrical double-layer capacitors. Nevertheless, the safety issue still remains a drawback for lithium-ion capacitors in practical operational environments because of the use of metallic lithium. Herein, single-phase Li5FeO4 with an antifluorite structure that acts as an alternative lithium source (instead of metallic lithium) is employed and its potential use for lithium-ion capacitors is verified. Abundant Li(+) amounts can be extracted from Li5FeO4 incorporated in the positive electrode and efficiently doped into the negative electrode during the first electrochemical charging. After the first Li(+) extraction, Li(+) does not return to the Li5FeO4 host structure and is steadily involved in the electrochemical reactions of the negative electrode during subsequent cycling. Various electrochemical and structural analyses support its superior characteristics for use as a promising lithium source. This versatile approach can yield a sufficient Li(+)-doping efficiency of >90% and improved safety as a result of the removal of metallic lithium from the cell. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

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

Common-Ground-Type Transformerless Inverters for Single-Phase Solar Photovoltaic Systems

DEFF Research Database (Denmark)

Siwakoti, Yam Prasad; Blaabjerg, Frede

2018-01-01

This paper proposes a family of novel flying capacitor transformerless inverters for single-phase photovoltaic (PV) systems. Each of the new topologies proposed is based on a flying capacitor principle and requires only four power switches and/or diodes, one capacitor, and a small filter at the o......This paper proposes a family of novel flying capacitor transformerless inverters for single-phase photovoltaic (PV) systems. Each of the new topologies proposed is based on a flying capacitor principle and requires only four power switches and/or diodes, one capacitor, and a small filter...... at the output stage. A simple unipolar sinusoidal pulse width modulation technique is used to modulate the inverter to minimize the switching loss, output current ripple, and the filter requirements. In general, the main advantages of the new inverter topologies are: 1) the negative polarity of the PV...... description of the operating principle with modulation techniques, design guidelines, and comprehensive comparisons is presented to reveal the properties and limitations of each topology in detail. Finally, experimental results of 1-kVA prototypes are presented to prove the concept and theoretical analysis...

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....

A Quasi-Solid-State Sodium-Ion Capacitor with High Energy Density.

Science.gov (United States)

Wang, Faxing; Wang, Xiaowei; Chang, Zheng; Wu, Xiongwei; Liu, Xiang; Fu, Lijun; Zhu, Yusong; Wu, Yuping; Huang, Wei

2015-11-18

A quasi-solid-state sodium-ion capacitor is demonstrated with nanoporous disordered carbon and macroporous graphene as the negative and positive electrodes, respectively, using a sodium-ion-conducting gel polymer electrolyte. It can operate at a cell voltage as high as 4.2 V with an energy density of record high 168 W h kg(-1). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A switched capacitor array based system for high-speed calorimetry

International Nuclear Information System (INIS)

Levi, M.; Bebek, C.; Ely, R.; Jared, R.; Kipnis, I.; Kirsten, F.; Kleinfelder, S.; Merrick, T.; Milgrome, O.

1991-12-01

A sixteen channel analog transient recorder with 256 cells per channel has been fabricated as an integrated circuit. The circuit uses switched capacitor array technology to achieve simultaneous read/write capability and twelve bit dynamic range. Combined with highly parallel analog-to-digital converter and readout control circuitry being developed this system should satisfy the demanding electronics requirements for calorimeter detectors at the SSC. The system design and test results are presented

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)

Energy transfer from a superconducting magnet to an inductive load

International Nuclear Information System (INIS)

Onishi, Toshitada; Miura, Akinori.

1977-01-01

Experiments on energy transfer between two superconducting magnets have been carried out using an inductive energy transfer system similar to the flying capacitor system developed at the Karlsruhe Institute. In the present system the capacitor is grounded and diodes are used instead of thyristors, and a fraction of stored energy is transferred to the capacitor only when the relay connected in parallel to the magnet is switched off. The capacitor is expected to have no constraint in size, while in the flying capacitor system the capacitor is required to exceed a threshold size. Consequently it is possible to shorten the transfer time to some extent in comparison with the one in the flying capacitor system. Transfer experiments have been carried out using a storage magnet with inductance of 1.2H and a load of 0.41H. The capacitance is 200μF. It is possible to transfer 80.1% of the stored energy of 221 J into the load in less than about 0.35 seconds. (auth.)

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...

Functionalized carbon nanotube based hybrid electrochemical capacitors using neutral bromide redox-active electrolyte for enhancing energy density

Science.gov (United States)

Tang, Xiaohui; Lui, Yu Hui; Chen, Bolin; Hu, Shan

2017-06-01

A hybrid electrochemical capacitor (EC) with enhanced energy density is realized by integrating functionalized carbon nanotube (FCNT) electrodes with redox-active electrolyte that has a neutral pH value (1 M Na2SO4 and 0.5 M KBr mixed aqueous solution). The negative electrode shows an electric double layer capacitor-type behavior. On the positive electrode, highly reversible Br-/Br3- redox reactions take place, presenting a battery-type behavior, which contributes to increase the capacitance of the hybrid cell. The voltage window of the whole cell is extended up to 1.5 V because of the high over-potentials of oxygen and hydrogen evolution reactions in the neutral electrolyte. Compared with raw CNT, the FCNT has better wettability in the aqueous electrolyte and contributes to increase the electric double layer capacitance of the cell. As a result, the maximum energy density of 28.3 Wh kg-1 is obtained from the hybrid EC at 0.5 A g-1 without sacrificing its power density, which is around 4 times larger than that of the electrical double layer capacitor constructed by FCNT electrodes and 1 M Na2SO4 electrolyte. Moreover, the discharge capacity retained 86.3% of its initial performance after 10000 cycles of galvanostatic charge and discharge test (10 A/g), suggesting its long life cycle even at high current loading.

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

A pulsed magnetic stress applied to Drosophila melanogaster flies

International Nuclear Information System (INIS)

Delle Side, D; Giuffreda, E; Nassisi, V; Velardi, L; Bozzetti, M P; Friscini, A; Specchia, V

2014-01-01

We report the development of a system to feed pulsed magnetic stress to biological samples. The device is based on a RLC circuit that transforms the energy stored in a high voltage capacitor into a magnetic field inside a coil. The field has been characterized and we found that charging the capacitor with 24 kV results in a peak field of 0.4 T. In order to test its effect, we applied such a stress to the Drosophila melanogaster model and we examined its bio-effects. We analysed, in the germ cells, the effects on the control of specific DNA repetitive sequences that are activated after different environmental stresses. The deregulation of these sequences causes genomic instability and chromosomes breaks leading to sterility. The magnetic field treatment did not produce effects on repetitive sequences in the germ cells of Drosophila. Hence, this field doesn't produce deleterious effects linked to repetitive sequences derepression.

A pulsed magnetic stress applied to Drosophila melanogaster flies

Science.gov (United States)

Delle Side, D.; Bozzetti, M. P.; Friscini, A.; Giuffreda, E.; Nassisi, V.; Specchia, V.; Velardi, L.

2014-04-01

We report the development of a system to feed pulsed magnetic stress to biological samples. The device is based on a RLC circuit that transforms the energy stored in a high voltage capacitor into a magnetic field inside a coil. The field has been characterized and we found that charging the capacitor with 24 kV results in a peak field of 0.4 T. In order to test its effect, we applied such a stress to the Drosophila melanogaster model and we examined its bio-effects. We analysed, in the germ cells, the effects on the control of specific DNA repetitive sequences that are activated after different environmental stresses. The deregulation of these sequences causes genomic instability and chromosomes breaks leading to sterility. The magnetic field treatment did not produce effects on repetitive sequences in the germ cells of Drosophila. Hence, this field doesn't produce deleterious effects linked to repetitive sequences derepression.

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...

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)

A Robust DC-Split-Capacitor Power Decoupling Scheme for Single-Phase Converter

DEFF Research Database (Denmark)

Yao, Wenli; Loh, Poh Chiang; Tang, Yi

2017-01-01

Instead of bulky electrolytic capacitors, active power decoupling circuit can be introduced to a single-phase converter for diverting second harmonic ripple away from its dc source or load. One possible circuit consists of a half-bridge and two capacitors in series for forming a dc-split capacitor......, instead of the usual single dc-link capacitor bank. Methods for regulating this power decoupler have earlier been developed, but almost always with equal capacitances assumed for forming the dc-split capacitor, even though it is not realistic in practice. The assumption should, hence, be evaluated more...... thoroughly, especially when it is shown in the paper that even a slight mismatch can render the power decoupling scheme ineffective and the IEEE 1547 standard to be breached. A more robust compensation scheme is, thus, needed for the dc-split capacitor circuit, as proposed and tested experimentally...

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)

Performance of Novel Randomly Oriented High Graphene Carbon in Lithium Ion Capacitors

Directory of Open Access Journals (Sweden)

Rahul S. Kadam

2018-01-01

Full Text Available The structure of carbon material comprising the anode is the key to the performance of a lithium ion capacitor. In addition to determining the capacity, the structure of the carbon material also determines the diffusion rate of the lithium ion into the anode which in turn controls power density which is vital in high rate applications. This paper covers details of systematic investigation of the performance of a structurally novel carbon, called Randomly Oriented High Graphene (ROHG carbon, and graphite in a high rate application device, that is, lithium ion capacitor. Electrochemical impedance spectroscopy shows that ROHG is less resistive and has faster lithium ion diffusion rates (393.7 × 10−3 S·s(1/2 compared to graphite (338.1 × 10−3 S·s(1/2. The impedance spectroscopy data is supported by the cell data showing that the ROHG carbon based device has energy density of 22.8 Wh/l with a power density of 4349.3 W/l, whereas baseline graphite based device has energy density of 5 Wh/l and power density of 4243.3 W/l. This data clearly shows advantage of the randomly oriented graphene platelet structure of ROHG in lithium ion capacitor performance.

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

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.

Gene expression response to EWS–FLI1 in mouse embryonic cartilage

Directory of Open Access Journals (Sweden)

Miwa Tanaka

2014-12-01

Full Text Available Ewing's sarcoma is a rare bone tumor that affects children and adolescents. We have recently succeeded to induce Ewing's sarcoma-like small round cell tumor in mice by expression of EWS–ETS fusion genes in murine embryonic osteochondrogenic progenitors. The Ewing's sarcoma precursors are enriched in embryonic superficial zone (eSZ cells of long bone. To get insights into the mechanisms of Ewing's sarcoma development, gene expression profiles between EWS–FLI1-sensitive eSZ cells and EWS–FLI1-resistant embryonic growth plate (eGP cells were compared using DNA microarrays. Gene expression of eSZ and eGP cells (total, 30 samples was evaluated with or without EWS–FLI1 expression 0, 8 or 48 h after gene transduction. Our data provide useful information for gene expression responses to fusion oncogenes in human sarcoma.

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.

Lithium and sodium ion capacitors with high energy and power densities based on carbons from recycled olive pits

Science.gov (United States)

Ajuria, Jon; Redondo, Edurne; Arnaiz, Maria; Mysyk, Roman; Rojo, Teófilo; Goikolea, Eider

2017-08-01

In this work, we are presenting both lithium and sodium ion capacitors (LIC and NIC) entirely based on electrodes designed from recycled olive pit bio-waste derived carbon materials. On the one hand, olive pits were pyrolized to obtain a low specific surface area semigraphitic hard carbon to be used as the ion intercalation (battery-type) negative electrode. On the other hand, the same hard carbon was chemically activated with KOH to obtain a high specific surface area activated carbon that was further used as the ion-adsorption (capacitor-type) positive electrode. Both electrodes were custom-made to be assembled in a hybrid cell to either build a LIC or NIC in the corresponding Li- and Na-based electrolytes. For comparison purposes, a symmetric EDLC supercapacitor cell using the same activated carbon in 1.5 M Et4NBF4/acetonitrile electrolyte was also built. Both LIC and NIC systems demonstrate remarkable energy and power density enhancement over its EDLC counterpart while showing good cycle life. This breakthrough offers the possibility to easily fabricate versatile hybrid ion capacitors, covering a wide variety of applications where different requirements are demanded.

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

More than apples and oranges - Detecting cancer with a fruit fly's antenna

Science.gov (United States)

Strauch, Martin; Lüdke, Alja; Münch, Daniel; Laudes, Thomas; Galizia, C. Giovanni; Martinelli, Eugenio; Lavra, Luca; Paolesse, Roberto; Ulivieri, Alessandra; Catini, Alexandro; Capuano, Rosamaria; di Natale, Corrado

2014-01-01

Cancer cells and non-cancer cells differ in their metabolism and they emit distinct volatile compound profiles, allowing to recognise cancer cells by their scent. Insect odorant receptors are excellent chemosensors with high sensitivity and a broad receptive range unmatched by current gas sensors. We thus investigated the potential of utilising the fruit fly's olfactory system to detect cancer cells. Using in vivo calcium imaging, we recorded an array of olfactory receptor neurons on the fruit fly's antenna. We performed multidimensional analysis of antenna responses, finding that cell volatiles from different cell types lead to characteristic response vectors. The distances between these response vectors are conserved across flies and can be used to discriminate healthy mammary epithelial cells from different types of breast cancer cells. This may expand the repertoire of clinical diagnostics, and it is the first step towards electronic noses equipped with biological sensors, integrating artificial and biological olfaction.

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.

Modeling of Structure Effect for Ferroelectric Capacitor Based on Poly(vinylidene fluoride-trifluoroethylene Ultrathin Films

Directory of Open Access Journals (Sweden)

Long Li

2017-12-01

Full Text Available The characteristics of ferroelectric capacitors with poly(vinylidene fluoride-trifluoroethlene (P(VDF-TrFE films have been studied at different structures of cell electrodes. It is suggested that the effect of electrode structures could induce changes of performance. Remarkably, cells with line electrodes display a better polarization and fatigue resistance than those with flat electrodes. For P(VDF-TrFE ultrathin films with different electrode structures, the models of charge compensation mechanism for depolarization field and domain fatigue decomposition are used to explain the effect of electrode structure. Furthermore, the driving voltage based on normal speed-functionality is designed, and the testing results show that the line electrode structure could induce a robust switching, which is determined by the free charges concentration in active layer. These findings provide an effective route to design the optimum structure for a ferroelectric capacitor based on P(VDF-TrFE copolymer ultrathin film.

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...

Fluctuation localization imaging-based fluorescence in situ hybridization (fliFISH) for accurate detection and counting of RNA copies in single cells

Energy Technology Data Exchange (ETDEWEB)

Cui, Yi; Hu, Dehong; Markillie, Lye Meng; Chrisler, William B.; Gaffrey, Matthew J.; Ansong, Charles; Sussel, Lori; Orr, Galya

2017-10-04

Quantitative gene expression analysis in intact single cells can be achieved using single molecule- based fluorescence in situ hybridization (smFISH). This approach relies on fluorescence intensity to distinguish between true signals, emitted from an RNA copy hybridized with multiple FISH sub-probes, and background noise. Thus, the precision in smFISH is often compromised by partial or nonspecific binding of sub-probes and tissue autofluorescence, limiting its accuracy. Here we provide an accurate approach for setting quantitative thresholds between true and false signals, which relies on blinking frequencies of photoswitchable dyes. This fluctuation localization imaging-based FISH (fliFISH) uses blinking frequency patterns, emitted from a transcript bound to multiple sub-probes, which are distinct from blinking patterns emitted from partial or nonspecifically bound sub-probes and autofluorescence. Using multicolor fliFISH, we identified radial gene expression patterns in mouse pancreatic islets for insulin, the transcription factor, NKX2-2, and their ratio (Nkx2-2/Ins2). These radial patterns, showing higher values in β cells at the islet core and lower values in peripheral cells, were lost in diabetic mouse islets. In summary, fliFISH provides an accurate, quantitative approach for detecting and counting true RNA copies and rejecting false signals by their distinct blinking frequency patterns, laying the foundation for reliable single-cell transcriptomics.

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

A review on electrochemical double-layer capacitors

International Nuclear Information System (INIS)

Sharma, Pawan; Bhatti, T.S.

2010-01-01

Various energy storage technologies have been developed in the market for various applications. Batteries flywheels, fuel cells are a few which are much common, those are being used in several countries and also research is also carrying on these technologies to make much better them. The electrochemical double-layer capacitor (EDLC) is an emerging technology, which really plays a key part in fulfilling the demands of electronic devices and systems, for present and future. This paper presents the historical background, classification, construction, modeling, testing, and voltage balancing of the EDLC technology. The applications of EDLC in electrical vehicles, power quality, and others are also discussed and their advantages over other storages technologies are also discussed.

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...

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

Fuel Cell/ Super-capacitor power management system assessment and Lifetime Cost study in a 500kVA UPS

Directory of Open Access Journals (Sweden)

Imen Ben Amira

2018-03-01

Full Text Available A 500 KVA Uninterruptible power supply (UPS using Fuel Cells (FC and super-capacitors (SCs was studied with the worst case of 10 minutes and eight hours of interruption per day. A power management system was established to control the FC and the SCs in order to extract the hybridization benefits with a comparison between a Proton exchange membrane FC (PEMFC working alone and another combined with SCs. Moreover, possible FC degradations were discussed. The start/stop cycling, the high-power loads and load changes degradations were taken into consideration in order to estimate the FC lifetime span using a prediction formula. Besides, the FC costs were studied to estimate the best average cost. Finally, the SCs filter constant time and their charging currents were revealed.

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

Na-ion capacitor using sodium pre-doped hard carbon and activated carbon

International Nuclear Information System (INIS)

Kuratani, Kentaro; Yao, Masaru; Senoh, Hiroshi; Takeichi, Nobuhiko; Sakai, Tetsuo; Kiyobayashi, Tetsu

2012-01-01

We assembled a sodium-ion capacitor (Na-IC) by combining sodium pre-doped hard carbon (HC) as the negative- and activated carbon (AC) as the positive-electrode. The electrochemical properties were compared with two lithium-ion capacitors (Li-ICs) in which the negative electrodes were prepared with Li pre-doped HC and mesocarbon microbeads (MCMB). The positive and negative electrodes were prepared using the established doctor blade method. The negative electrodes were galvanostatically pre-doped with Na or Li to 80% of the full capacity of carbons. The potential of the negative electrodes after pre-doping was around 0.0 V vs. Na/Na + or Li/Li + , which resulted in the higher output potential difference of the Na-IC and Li-ICs than that of the conventional electrochemical double-layer capacitors (EDLCs) because AC positive electrode works in the same principle both in the ion capacitors and in the EDLC. The state-of-charge of the negative electrode varied 80 ± 10% during the electrochemical charging and discharging. The capacity of the cell was evaluated using galvanostatic charge–discharge measurement. At the discharge current density of 10 mA cm −2 , the Na-IC maintained 70% of the capacity that obtained at the current density of 0.5 mA cm −2 , which was comparable to the Li-ICs. At 50 mA cm −2 , the capacities of the Li-IC(MCMB) and the Na-IC dropped to 20% whereas the Li-IC(HC) retained 30% of the capacity observed at 0.5 mA cm −2 . The capacities of the Na-IC and Li-ICs decreased by 9% and 3%, respectively, after 1000 cycles of charging and discharging.

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

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...

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)

High activity antioxidant enzymes protect flying-fox haemoglobin against damage: an evolutionary adaptation for flight?

Science.gov (United States)

Reinke, N B; O'Brien, G M

2006-11-01

Flying-foxes are better able to defend haemoglobin against autoxidation than non-volant mammals such as sheep. When challenged with the common physiological oxidant, hydrogen peroxide, haemolysates of flying-fox red blood cells (RBC) were far less susceptible to methaemoglobin formation than sheep. Challenge with 1-acetyl-2-phenylhydrazine (APH) caused only half as much methaemoglobin formation in flying-fox as in ovine haemolysates. When intact cells were challenged with phenazine methosulfate (PMS), flying-fox RBC partially reversed the oxidant damage, and reduced methaemoglobin from 40 to 20% over 2 h incubation, while ovine methaemoglobin remained at 40%. This reflected flying-fox cells' capacity to replenish GSH fast enough that it did not deplete beyond 50%, while ovine RBC GSH was depleted to around 20%. The greater capacity of flying-foxes to defend haemoglobin against oxidant damage may be explained in part by antioxidant enzymes catalase, superoxide dismutase and cytochrome-b ( 5 ) reductase having two- to four-fold higher activity than in sheep (P foxes.

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

Particle-in-cell simulations of magnetically driven reconnection using laser-powered capacitor coils

Science.gov (United States)

Huang, Kai; Lu, Quanming; Gao, Lan; Ji, Hantao; Wang, Xueyi; Fan, Feibin

2018-05-01

In this paper, we propose an experimental scheme to fulfill magnetically driven reconnections. Here, two laser beams are focused on a capacitor-coil target and then strong currents are wired in two parallel circular coils. Magnetic reconnection occurs between the two magnetic bubbles created by the currents in the two parallel circular coils. A two-dimensional particle-in-cell simulation model in the cylindrical coordinate is used to investigate such a process, and the simulations are performed in the (r ,z ) plane. The results show that with the increase of the currents in the two coils, the associated magnetic bubbles expand and a current sheet is formed between the two bubbles. Magnetic reconnection occurs when the current sheet is sufficiently thin. A quadrupole structure of the magnetic field in the θ direction ( Bθ ) is generated in the diffusion region and a strong electron current along the r direction ( Je r ) is also formed due to the existence of the high-speed electron flow away from the X line in the center of the outflow region. Because the X line is a circle along the θ direction, the convergence of the plasma flow around r =0 will lead to the asymmetry of Je r and Bθ between the two outflow regions of magnetic reconnection.

Influence of the electrolyte distribution near the micropores of the activated carbon (AC) electrode on high rate performance of high voltage capacitors

International Nuclear Information System (INIS)

Lee, Chung ho; Xu, Fan; Jung, Cheolsoo

2014-01-01

Highlights: • TFB can enhance the rate performance of high voltage capacitors. • TFB can suppress to increase the discharge slope to improve the cell performance. • TFB decreases the charge transfer resistance of an AC cell. • TFB affects the distribution of the electrolyte components near the microporous AC. - Abstract: This paper presents a method to enhance the rate performance of high voltage capacitors using an electrolyte additive, 1,3,5-trifluorobenzene (TFB). With increasing discharge rate, the capacity of the activated carbon (AC)/lithium (Li) cell decreases with increasing the slope of the discharge curve and its potential drop at 4.6 V. By adding TFB, the discharge slope improves to increase the rate performance of the cell, and EIS showed that the charge transfer resistance (Rc) of the AC cell decreases. These results suggest that TFB affects the distribution of the electrolyte components near the microporous AC and improves the rate performance of the AC cell

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

Effect of Grinding Fineness of Fly Ash on the Properties of Geopolymer Foam

Directory of Open Access Journals (Sweden)

Szabó R.

2017-06-01

Full Text Available Present paper deals with the development of geopolymer foam prepared from ground F class power station fly ash. The effect of the fly ash fineness on the rheology of the geopolymer paste and the foam properties have been investigated. The raw fly ash was ground in a ball mill for various duration, 5, 10, 20, 30, 60 and 120 min. Geopolymer paste was prepared from the raw and ground fly ash with NaOH – sodium silicate mixture as alkaline activator. Geopolymer foam production was made using H2O2 as foaming agent. Additionally, the geopolymer material structure was investigated by Fourier transform infrared spectrometer, the foam cell structure was monitored using optical microscopy. The rheological behaviour of the geopolymer paste changed due to the grinding of fly ash (from Bingham plastic to Newtonian liquid. Grinding of fly ash has a significant effect on the physical properties as well as on the cell structure of the geopolymer foam.

High Energy Density Aqueous Electrochemical Capacitors with a KI-KOH Electrolyte.

Science.gov (United States)

Wang, Xingfeng; Chandrabose, Raghu S; Chun, Sang-Eun; Zhang, Tianqi; Evanko, Brian; Jian, Zelang; Boettcher, Shannon W; Stucky, Galen D; Ji, Xiulei

2015-09-16

We report a new electrochemical capacitor with an aqueous KI-KOH electrolyte that exhibits a higher specific energy and power than the state-of-the-art nonaqueous electrochemical capacitors. In addition to electrical double layer capacitance, redox reactions in this device contribute to charge storage at both positive and negative electrodes via a catholyte of IOx-/I- couple and a redox couple of H2O/Had, respectively. Here, we, for the first time, report utilizing IOx-/I- redox couple for the positive electrode, which pins the positive electrode potential to be 0.4-0.5 V vs Ag/AgCl. With the positive electrode potential pinned, we can polarize the cell to 1.6 V without breaking down the aqueous electrolyte so that the negative electrode potential could reach -1.1 V vs Ag/AgCl in the basic electrolyte, greatly enhancing energy storage. Both mass spectroscopy and Raman spectrometry confirm the formation of IO3- ions (+5) from I- (-1) after charging. Based on the total mass of electrodes and electrolyte in a practically relevant cell configuration, the device exhibits a maximum specific energy of 7.1 Wh/kg, operates between -20 and 50 °C, provides a maximum specific power of 6222 W/kg, and has a stable cycling life with 93% retention of the peak specific energy after 14,000 cycles.

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...

FlyMAD: rapid thermogenetic control of neuronal activity in freely walking Drosophila.

Science.gov (United States)

Bath, Daniel E; Stowers, John R; Hörmann, Dorothea; Poehlmann, Andreas; Dickson, Barry J; Straw, Andrew D

2014-07-01

Rapidly and selectively modulating the activity of defined neurons in unrestrained animals is a powerful approach in investigating the circuit mechanisms that shape behavior. In Drosophila melanogaster, temperature-sensitive silencers and activators are widely used to control the activities of genetically defined neuronal cell types. A limitation of these thermogenetic approaches, however, has been their poor temporal resolution. Here we introduce FlyMAD (the fly mind-altering device), which allows thermogenetic silencing or activation within seconds or even fractions of a second. Using computer vision, FlyMAD targets an infrared laser to freely walking flies. As a proof of principle, we demonstrated the rapid silencing and activation of neurons involved in locomotion, vision and courtship. The spatial resolution of the focused beam enabled preferential targeting of neurons in the brain or ventral nerve cord. Moreover, the high temporal resolution of FlyMAD allowed us to discover distinct timing relationships for two neuronal cell types previously linked to courtship song.

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....

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.

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.

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.

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...

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.

FliO Regulation of FliP in the Formation of the Salmonella enterica Flagellum

Science.gov (United States)

Barker, Clive S.; Meshcheryakova, Irina V.; Kostyukova, Alla S.; Samatey, Fadel A.

2010-01-01

The type III secretion system of the Salmonella flagellum consists of 6 integral membrane proteins: FlhA, FlhB, FliO, FliP, FliQ, and FliR. However, in some other type III secretion systems, a homologue of FliO is apparently absent, suggesting it has a specialized role. Deleting the fliO gene from the chromosome of a motile strain of Salmonella resulted in a drastic decrease of motility. Incubation of the ΔfliO mutant strain in motility agar, gave rise to pseudorevertants containing extragenic bypass mutations in FliP at positions R143H or F190L. Using membrane topology prediction programs, and alkaline phosphatase or GFPuv chimeric protein fusions into the FliO protein, we demonstrated that FliO is bitopic with its N-terminus in the periplasm and C-terminus in the cytoplasm. Truncation analysis of FliO demonstrated that overexpression of FliO43–125 or FliO1–95 was able to rescue motility of the ΔfliO mutant. Further, residue leucine 91 in the cytoplasmic domain was identified to be important for function. Based on secondary structure prediction, the cytoplasmic domain, FliO43–125, should contain beta-structure and alpha-helices. FliO43–125-Ala was purified and studied using circular dichroism spectroscopy; however, this domain was disordered, and its structure was a mixture of beta-sheet and random coil. Coexpression of full-length FliO with FliP increased expression levels of FliP, but coexpression with the cytoplasmic domain of FliO did not enhance FliP expression levels. Overexpression of the cytoplasmic domain of FliO further rescued motility of strains deleted for the fliO gene expressing bypass mutations in FliP. These results suggest FliO maintains FliP stability through transmembrane domain interaction. The results also demonstrate that the cytoplasmic domain of FliO has functionality, and it presumably becomes structured while interacting with its binding partners. PMID:20941389

FliO regulation of FliP in the formation of the Salmonella enterica flagellum.

Directory of Open Access Journals (Sweden)

Clive S Barker

2010-09-01

Full Text Available The type III secretion system of the Salmonella flagellum consists of 6 integral membrane proteins: FlhA, FlhB, FliO, FliP, FliQ, and FliR. However, in some other type III secretion systems, a homologue of FliO is apparently absent, suggesting it has a specialized role. Deleting the fliO gene from the chromosome of a motile strain of Salmonella resulted in a drastic decrease of motility. Incubation of the ΔfliO mutant strain in motility agar, gave rise to pseudorevertants containing extragenic bypass mutations in FliP at positions R143H or F190L. Using membrane topology prediction programs, and alkaline phosphatase or GFPuv chimeric protein fusions into the FliO protein, we demonstrated that FliO is bitopic with its N-terminus in the periplasm and C-terminus in the cytoplasm. Truncation analysis of FliO demonstrated that overexpression of FliO₄₃-₁₂₅ or FliO₁-₉₅ was able to rescue motility of the ΔfliO mutant. Further, residue leucine 91 in the cytoplasmic domain was identified to be important for function. Based on secondary structure prediction, the cytoplasmic domain, FliO₄₃-₁₂₅, should contain beta-structure and alpha-helices. FliO₄₃-₁₂₅-Ala was purified and studied using circular dichroism spectroscopy; however, this domain was disordered, and its structure was a mixture of beta-sheet and random coil. Coexpression of full-length FliO with FliP increased expression levels of FliP, but coexpression with the cytoplasmic domain of FliO did not enhance FliP expression levels. Overexpression of the cytoplasmic domain of FliO further rescued motility of strains deleted for the fliO gene expressing bypass mutations in FliP. These results suggest FliO maintains FliP stability through transmembrane domain interaction. The results also demonstrate that the cytoplasmic domain of FliO has functionality, and it presumably becomes structured while interacting with its binding partners.

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.

Hsa-mir-145 is the top EWS-FLI1-repressed microRNA involved in a positive feedback loop in Ewing's sarcoma.

Science.gov (United States)

Ban, J; Jug, G; Mestdagh, P; Schwentner, R; Kauer, M; Aryee, D N T; Schaefer, K-L; Nakatani, F; Scotlandi, K; Reiter, M; Strunk, D; Speleman, F; Vandesompele, J; Kovar, H

2011-05-05

EWS-FLI1 is a chromosome translocation-derived chimeric transcription factor that has a central and rate-limiting role in the pathogenesis of Ewing's sarcoma. Although the EWS-FLI1 transcriptomic signature has been extensively characterized on the mRNA level, information on its impact on non-coding RNA expression is lacking. We have performed a genome-wide analysis of microRNAs affected by RNAi-mediated silencing of EWS-FLI1 in Ewing's sarcoma cell lines, and differentially expressed between primary Ewing's sarcoma and mesenchymal progenitor cells. Here, we report on the identification of hsa-mir-145 as the top EWS-FLI1-repressed microRNA. Upon knockdown of EWS-FLI1, hsa-mir-145 expression dramatically increases in all Ewing's sarcoma cell lines tested. Vice versa, ectopic expression of the microRNA in Ewing's sarcoma cell lines strongly reduced EWS-FLI1 protein, whereas transfection of an anti-mir to hsa-mir-145 increased the EWS-FLI1 levels. Reporter gene assays revealed that this modulation of EWS-FLI1 protein was mediated by the microRNA targeting the FLI1 3'-untranslated region. Mutual regulations of EWS-FLI1 and hsa-mir-145 were mirrored by an inverse correlation between their expression levels in four of the Ewing's sarcoma cell lines tested. Consistent with the role of EWS-FLI1 in Ewing's sarcoma growth regulation, forced hsa-mir-145 expression halted Ewing's sarcoma cell line growth. These results identify feedback regulation between EWS-FLI1 and hsa-mir-145 as an important component of the EWS-FLI1-mediated Ewing's sarcomagenesis that may open a new avenue to future microRNA-mediated therapy of this devastating malignant disease.

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.

Report on the achievement of verification for FY 1997-1999. Verification survey of a capacitor system for power leveling of the photovoltaic power generation; 1997 nendo kara 1999 nendo taiyoko hatsuden shutsuryoku heijunkayo capacitor system no jissho chosa seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

The purpose of this verification survey is to confirm the performance and reliability with which a new large capacity capacitor works as power leveling use and partial power peak shift back-up use in the photovoltaic power system. The results of FY 1997 are as follows: (1) Verification using jelly-role type cells. (2) Trial manufacture of stacking cells. In (1), jelly-role type cells were manufactured using an electrode composed of aluminum foil and activated carbon layer and the organic electrolyte. The obtained cell capacitance was 6,000F on average and the energy density 5.4-5.6Wh/L. The experiment on the constant power load of a capacitor bank constructed with four 6,000F cells connected in series was carried out to confirm discharge energy of 25Wh between 12V and 3V. In (2), stacking rectangular type cells were trially manufactured by the electrode composed of two types of electrode; press type and sheet type electrodes. The cell capacitance was approximately 3,500F at sheet electrode cell, and the energy density 7.2Wh/L. To improve the cell performance, a relation was studied between the pore distribution of activated carbon and the double layer capacity, and the material higher than the conventional one in capacity per volume was found out. Studies were also made of trial fabrication of charge/discharge circuits and the experiment and the voltage balance. (NEDO)

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.

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.

Homologue Pairing in Flies and Mammals: Gene Regulation When Two Are Involved

OpenAIRE

Apte, Manasi S.; Meller, Victoria H.

2011-01-01

Chromosome pairing is usually discussed in the context of meiosis. Association of homologues in germ cells enables chromosome segregation and is necessary for fertility. A few organisms, such as flies, also pair their entire genomes in somatic cells. Most others, including mammals, display little homologue pairing outside of the germline. Experimental evidence from both flies and mammals suggests that communication between homologues contributes to normal genome regulation. This paper will co...

Treatment of MSW fly ashes using the electrodialytic remediation technique

DEFF Research Database (Denmark)

Ferreira, Celia; Ribeiro, Alexandra B.; Ottosen, Lisbeth M.

2004-01-01

In the present work the electrodialytic remediation technique is applied for the treatment of fly ash, a hazardous by-product resulting from the incineration of municipal solid waste. Results are presented for an experiment conducted for 40 days at 38 mA, with a continuously stirred cell. Experim......In the present work the electrodialytic remediation technique is applied for the treatment of fly ash, a hazardous by-product resulting from the incineration of municipal solid waste. Results are presented for an experiment conducted for 40 days at 38 mA, with a continuously stirred cell...

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....

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)

Temperature aspect of degradation of electrochemical double-layer capacitors (EDLC)

Science.gov (United States)

Baek, Dong-Cheon; Kim, Hyun-Ho; Lee, Soon-Bok

2015-03-01

Electric double layer capacitors (EDLC) cells have a process variation and temperature dependency in capacitance so that balancing is required when they are connected in series, which includes electronic voltage management based on capacitance monitoring. This paper measured temperature aspect of capacitance periodically to monitor health and degradation behavior of EDLC stressed under high temperatures and zero below temperatures respectively, which enables estimation of the state of health (SOH) regardless of temperature. At high temperature, capacitance saturation and delayed expression of degradation was observed. After cyclic stress at zero below temperature, less effective degradation and time recovery phenomenon were occurred.

PI3K/AKT signaling modulates transcriptional expression of EWS/FLI1 through specificity protein 1.

Science.gov (United States)

Giorgi, Chiara; Boro, Aleksandar; Rechfeld, Florian; Lopez-Garcia, Laura A; Gierisch, Maria E; Schäfer, Beat W; Niggli, Felix K

2015-10-06

Ewing sarcoma (ES) is the second most frequent bone cancer in childhood and is characterized by the presence of the balanced translocation t(11;22)(q24;q12) in more than 85% of cases, generating a dysregulated transcription factor EWS/FLI1. This fusion protein is an essential oncogenic component of ES development which is necessary for tumor cell maintenance and represents an attractive therapeutic target. To search for modulators of EWS/FLI1 activity we screened a library of 153 targeted compounds and identified inhibitors of the PI3K pathway to directly modulate EWS/FLI1 transcription. Surprisingly, treatment of four different ES cell lines with BEZ235 resulted in down regulation of EWS/FLI1 mRNA and protein by ~50% with subsequent modulation of target gene expression. Analysis of the EWS/FLI1 promoter region (-2239/+67) using various deletion constructs identified two 14 bp minimal elements as being important for EWS/FLI1 transcription. We identified SP1 as modulator of EWS/FLI1 gene expression and demonstrated direct binding to one of these regions in the EWS/FLI1 promoter by EMSA and ChIP experiments. These results provide the first insights on the transcriptional regulation of EWS/FLI1, an area that has not been investigated so far, and offer an additional molecular explanation for the known sensitivity of ES cell lines to PI3K inhibition.

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...

Cementing Efficiency of Low Calcium Fly Ash in Fly Ash Concretes

OpenAIRE

T. D. Gunneswara Rao; Mudimby Andal

2014-01-01

Research on the utilization of fly ash will no longer refer the fly ash as a waste material of thermal power plants. Use of fly ash in concrete making, makes the concrete economical as well as durable. The fly ash is being added to the concrete in three ways namely, as partial replacement to cement, as partial replacement to fine aggregates and as admixture. Addition of fly ash to the concrete in any one of the form mentioned above, makes the concrete more workable and durable than the conven...

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.

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.

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

Sub-millimeter arbitrary arrangements of monolithically micro-scale electrical double layer capacitors

International Nuclear Information System (INIS)

Laszczyk, Karolina U; Kazufumi, Kobashi; Sakurai, Shunsuke; Sekiguchi, Atsuko; Futaba, Don N; Yamada, Takeo; Hata, Kenji

2015-01-01

We report the investigation on the reproducibility of micro-scale electric double layer capacitors (micro-EDLCs). The micro-EDLC components were fabricated parallel using photolithography, wet and dry processing. Electrodes of the micro-EDLCs are highly dense packed Single Wall Carbon Nanotubes (SWCNTs) that form a mesh structure. The micro- EDLCs are connected 1-10 in series and in parallel being unified electrical circuits to tune the capacitance and the operational voltage. To confirm the reproducibility of the cells as well as the yield we performed electrochemical measurements in order to define the performance uniformity between cells strings and individual cells connected in a string. For 1-10 cells in series and in parallel the trends for the capacitance and operational voltage satisfied electrophysics rules governing cells addition. However, the measurements of the individual cells in a string revealed the significant performance discrepancy that might result in a shorten life cycling of a circuit. (paper)

Sub-millimeter arbitrary arrangements of monolithically micro-scale electrical double layer capacitors

Science.gov (United States)

Laszczyk, Karolina U.; Kazufumi, Kobashi; Sakurai, Shunsuke; Sekiguchi, Atsuko; Futaba, Don N.; Yamada, Takeo; Hata, Kenji

2015-12-01

We report the investigation on the reproducibility of micro-scale electric double layer capacitors (micro-EDLCs). The micro-EDLC components were fabricated parallel using photolithography, wet and dry processing. Electrodes of the micro-EDLCs are highly dense packed Single Wall Carbon Nanotubes (SWCNTs) that form a mesh structure. The micro- EDLCs are connected 1-10 in series and in parallel being unified electrical circuits to tune the capacitance and the operational voltage. To confirm the reproducibility of the cells as well as the yield we performed electrochemical measurements in order to define the performance uniformity between cells strings and individual cells connected in a string. For 1-10 cells in series and in parallel the trends for the capacitance and operational voltage satisfied electrophysics rules governing cells addition. However, the measurements of the individual cells in a string revealed the significant performance discrepancy that might result in a shorten life cycling of a circuit.

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.

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.

Pseudocapacitive Sodium Storage in Mesoporous Single-Crystal-like TiO2-Graphene Nanocomposite Enables High-Performance Sodium-Ion Capacitors.

Science.gov (United States)

Le, Zaiyuan; Liu, Fang; Nie, Ping; Li, Xinru; Liu, Xiaoyan; Bian, Zhenfeng; Chen, Gen; Wu, Hao Bin; Lu, Yunfeng

2017-03-28

Sodium-ion capacitors can potentially combine the virtues of high power capability of conventional electrochemical capacitors and high energy density of batteries. However, the lack of high-performance electrode materials has been the major challenge of sodium-based energy storage devices. In this work, we report a microwave-assisted synthesis of single-crystal-like anatase TiO 2 mesocages anchored on graphene as a sodium storage material. The architecture of the nanocomposite results in pseudocapacitive charge storage behavior with fast kinetics, high reversibility, and negligible degradation to the micro/nanostructure. The nanocomposite delivers a high capacity of 268 mAh g -1 at 0.2 C, which remains 126 mAh g -1 at 10 C for over 18 000 cycles. Coupling with a carbon-based cathode, a full cell of sodium-ion capacitor successfully demonstrates a high energy density of 64.2 Wh kg -1 at 56.3 W kg -1 and 25.8 Wh kg -1 at 1357 W kg -1 , as well as an ultralong lifespan of 10 000 cycles with over 90% of capacity retention.

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,

Can E. coli fly?

DEFF Research Database (Denmark)

Lindeberg, Yrja Lisa; Egedal, Karen; Hossain, Zenat Zebin

2018-01-01

, and the numbers of flies landing on the exposed rice were counted. Following exposure, the surface of the rice was microbiologically and molecularly analysed for the presence of E. coli and genes of diarrheagenic E. coli and Shigella strains. RESULTS: Rice was at greater risk (p ... with E. coli if flies landed on the rice than if no flies landed on the rice (odds ratio 5·4 (p ...-landings, the average CFU per fly-landing was > 0·6 x 103 CFU. Genes of diarrheagenic E. coli and Shigella species were detected in 39 of 60 (65%) of exposed rice samples. Two fly species were identified; the common housefly (Musca domestica) and the oriental latrine fly (Chrysomya megacephala). CONCLUSION: Flies may...

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.

Hybrid lithium-ion capacitor with LiFePO4/AC composite cathode - Long term cycle life study, rate effect and charge sharing analysis

Science.gov (United States)

Shellikeri, A.; Yturriaga, S.; Zheng, J. S.; Cao, W.; Hagen, M.; Read, J. A.; Jow, T. R.; Zheng, J. P.

2018-07-01

Energy storage devices, which can combine the advantages of lithium-ion battery with that of electric double layer capacitor, are of prime interest. Recently, composite cathodes, which combine a battery material with capacitor material, have shown promise in enhancing life cycle and energy/power performances. Lithium-ion capacitor (LIC), with unique charge storage mechanism of combining a pre-lithiated battery anode with a capacitor cathode, is one such device which has the potential to synergistically incorporate the composite cathode to enhance capacity and cycle life. We report here a hybrid LIC consisting of a lithium iron phosphate (LiFePO4-LFP)/Activated Carbon composite cathode in combination with a hard carbon anode, by integrating the cycle life and capacity enhancing strategies of a dry method of electrode fabrication, anode pre-lithiation and a 3:1 anode to cathode capacity ratio, demonstrating a long cycle life, while elaborating on the charge sharing between the faradaic and non-faradaic mechanism in the battery and capacitor materials, respectively in the composite cathode. An excellent cell capacity retention of 94% (1000 cycles at 1C) and 92% (100,000 cycles at 60C) were demonstrated, while retaining 78% (over 6000 cycles at 2.7C) and 67% (over 70,000 cycles at 43C) of the LFP capacity in the composite cathode.

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.

Fly ash carbon passivation

Science.gov (United States)

La Count, Robert B; Baltrus, John P; Kern, Douglas G

2013-05-14

A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

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.

ADAPTIVE MATHEMATICAL MODEL OF THERMAL PROCESSES IN A COSINE POWER CAPACITOR

Directory of Open Access Journals (Sweden)

D. I. Zalizny

2016-01-01

Full Text Available The existing protection and diagnostics systems are unable to detect the power capacitor abnormal heating caused by the development of its malfunctions. A diagnosis technique is presented that provides discovering such a heating at its early manifestation. The technique includes algorithms and an apparatus component in a form of a digital device, and it is based on continuous measuring of a capacitor body surface temperature, ambient temperature, voltages and currents from the power source. On the basis of measured values the active power losses in the capacitor and the temperature of the hottest point of its dielectric were calculated. Thereafter, the calculated average daily values of the temperature was analyzed, and, should the tendency of permanent increase of these values is detected, the diagnosis alarms of danger levels of abnormal heating are formed, viz. a low level, an average level, a high level and a very high level. The presented algorithms have been developed heuristically. Their final formation is possible only after years of operation of the proposed diagnosis system applied to the real objects. Because of application of the diagnosis system the probability of capacitor units’ failure will be lower and thus the dependability of the power supply may be higher. The implementation of the developed system will reduce the probability of sudden failure of capacitor units, and, correspondingly, will increase the reliability of the electricity supply system of an enterprise.

FliO Regulation of FliP in the Formation of the Salmonella enterica Flagellum

OpenAIRE

Barker, Clive S.; Meshcheryakova, Irina V.; Kostyukova, Alla S.; Samatey, Fadel A.

2010-01-01

The type III secretion system of the Salmonella flagellum consists of 6 integral membrane proteins: FlhA, FlhB, FliO, FliP, FliQ, and FliR. However, in some other type III secretion systems, a homologue of FliO is apparently absent, suggesting it has a specialized role. Deleting the fliO gene from the chromosome of a motile strain of Salmonella resulted in a drastic decrease of motility. Incubation of the ΔfliO mutant strain in motility agar, gave rise to pseudorevertants containing extrageni...

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.

Aging of electrochemical double layer capacitors with acetonitrile-based electrolyte at elevated voltages

International Nuclear Information System (INIS)

Ruch, P.W.; Cericola, D.; Foelske-Schmitz, A.; Koetz, R.; Wokaun, A.

2010-01-01

Laboratory-scale electrochemical capacitor cells with bound activated carbon electrodes and acetonitrile-based electrolyte were aged at various elevated constant cell voltages between 2.75 V and 4.0 V. During the constant voltage tests, the cell capacitance as well as the capacitance and resistance of each electrode was determined. Following each aging experiment, the cells were analyzed by means of electrochemical impedance spectroscopy, and the individual electrodes were characterized by gas adsorption and X-ray photoelectron spectroscopy. At cell voltages above 3.0 V, the positive electrode ages much faster than the negative. Both the capacitance loss and resistance increase of the cell could be totally attributed to the positive electrode. At cell voltages above 3.5 V also the negative electrode aged significantly. X-ray photoelectron spectroscopy indicated the presence of degradation products on the electrode surface with a much thicker layer on the positive electrode. Simultaneously, a significant decrease in electrode porosity could be detected by gas adsorption.

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.

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

Mercury release from fly ashes and hydrated fly ash cement pastes

Science.gov (United States)

Du, Wen; Zhang, Chao-yang; Kong, Xiang-ming; Zhuo, Yu-qun; Zhu, Zhen-wu

2018-04-01

The large-scale usage of fly ash in cement and concrete introduces mercury (Hg) into concrete structures and a risk of secondary emission of Hg from the structures during long-term service was evaluated. Three fly ashes were collected from coal-fired power plants and three blend cements were prepared by mixing Ordinary Portland cement (OPC) with the same amount of fly ash. The releasing behaviors of Hg0 from the fly ash and the powdered hydrated cement pastes (HCP) were measured by a self-developed Hg measurement system, where an air-blowing part and Hg collection part were involved. The Hg release of fly ashes at room temperature varied from 25.84 to 39.69 ng/g fly ash during 90-days period of air-blowing experiment. In contrast, the Hg release of the HCPs were in a range of 8.51-18.48 ng/g HCP. It is found that the Hg release ratios of HCPs were almost the same as those of the pure fly ashes, suggesting that the hydration products of the HCP have little immobilization effect on Hg0. Increasing temperature and moisture content markedly promote the Hg release.

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.

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

Fly ash aggregates. Vliegaskunstgrind

Energy Technology Data Exchange (ETDEWEB)

1983-03-01

A study has been carried out into artificial aggregates made from fly ash, 'fly ash aggregates'. Attention has been drawn to the production of fly ash aggregates in the Netherlands as a way to obviate the need of disposal of fly ash. Typical process steps for the manufacturing of fly ash aggregates are the agglomeration and the bonding of fly ash particles. Agglomeration techniques are subdivided into agitation and compaction, bonding methods into sintering, hydrothermal and 'cold' bonding. In sintering no bonding agent is used. The fly ash particles are more or less welded together. Sintering in general is performed at a temperature higher than 900 deg C. In hydrothermal processes lime reacts with fly ash to a crystalline hydrate at temperatures between 100 and 250 deg C at saturated steam pressure. As a lime source not only lime as such, but also portland cement can be used. Cold bonding processes rely on reaction of fly ash with lime or cement at temperatures between 0 and 100 deg C. The pozzolanic properties of fly ash are used. Where cement is applied, this bonding agent itself contributes also to the strength development of the artificial aggregate. Besides the use of lime and cement, several processes are known which make use of lime containing wastes such as spray dry absorption desulfurization residues or fluid bed coal combustion residues. (In Dutch)

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.

Hydration of fly ash cement and microstructure of fly ash cement pastes

Energy Technology Data Exchange (ETDEWEB)

Shiyuan, H.

1981-01-01

The strength development and hydration of fly ash cement and the influence of addition of gypsum on those were studied at normal and elevated temperatures. It was found that an addition of a proper amount of gypsum to fly ash cement could accelerate the pozzolanic reaction between CH and fly ash, and as a result, increase the strength of fly ash cement pastes after 28 days.

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...

An Improved Fruit Fly Optimization Algorithm Inspired from Cell Communication Mechanism

Directory of Open Access Journals (Sweden)

Chuncai Xiao

2015-01-01

Full Text Available Fruit fly optimization algorithm (FOA invented recently is a new swarm intelligence method based on fruit fly’s foraging behaviors and has been shown to be competitive with existing evolutionary algorithms, such as particle swarm optimization (PSO algorithm. However, there are still some disadvantages in the FOA, such as low convergence precision, easily trapped in a local optimum value at the later evolution stage. This paper presents an improved FOA based on the cell communication mechanism (CFOA, by considering the information of the global worst, mean, and best solutions into the search strategy to improve the exploitation. The results from a set of numerical benchmark functions show that the CFOA outperforms the FOA and the PSO in most of the experiments. Further, the CFOA is applied to optimize the controller for preoxidation furnaces in carbon fibers production. Simulation results demonstrate the effectiveness of the CFOA.

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.

Capacitor with a composite carbon foam electrode

Science.gov (United States)

Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

1999-01-01

Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid partides being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

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)

A zebrafish transgenic model of Ewing's sarcoma reveals conserved mediators of EWS-FLI1 tumorigenesis.

Science.gov (United States)

Leacock, Stefanie W; Basse, Audrey N; Chandler, Garvin L; Kirk, Anne M; Rakheja, Dinesh; Amatruda, James F

2012-01-01

Ewing's sarcoma, a malignant bone tumor of children and young adults, is a member of the small-round-blue-cell tumor family. Ewing's sarcoma family tumors (ESFTs), which include peripheral primitive neuroectodermal tumors (PNETs), are characterized by chromosomal translocations that generate fusions between the EWS gene and ETS-family transcription factors, most commonly FLI1. The EWS-FLI1 fusion oncoprotein represents an attractive therapeutic target for treatment of Ewing's sarcoma. The cell of origin of ESFT and the molecular mechanisms by which EWS-FLI1 mediates tumorigenesis remain unknown, and few animal models of Ewing's sarcoma exist. Here, we report the use of zebrafish as a vertebrate model of EWS-FLI1 function and tumorigenesis. Mosaic expression of the human EWS-FLI1 fusion protein in zebrafish caused the development of tumors with histology strongly resembling that of human Ewing's sarcoma. The incidence of tumors increased in a p53 mutant background, suggesting that the p53 pathway suppresses EWS-FLI1-driven tumorigenesis. Gene expression profiling of the zebrafish tumors defined a set of genes that might be regulated by EWS-FLI1, including the zebrafish ortholog of a crucial EWS-FLI1 target gene in humans. Stable zebrafish transgenic lines expressing EWS-FLI1 under the control of the heat-shock promoter exhibit altered embryonic development and defective convergence and extension, suggesting that EWS-FLI1 interacts with conserved developmental pathways. These results indicate that functional targets of EWS-FLI1 that mediate tumorigenesis are conserved from zebrafish to human and provide a novel context in which to study the function of this fusion oncogene.

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.

Effects of ion insertion on cycling performance of miniaturized electrochemical capacitor of carbon nanotubes array.

Science.gov (United States)

Tsai, Dah-Shyang; Chang, Chuan-hua; Chiang, Wei-Wen; Lee, Kuei-Yi; Huang, Ying-Sheng

2014-10-24

Capacity degradation and ion insertion of a miniaturized electrochemical capacitor are studied using ionic liquid [EMI] [TFSI] as the electrolyte. This capacitor is featured with two comb-like electrodes of vertical carbon nanotubes, ∼70 μm in height and 20 μm in interelectrode gap. We quantify the levels of ion insertion damage with Raman spectroscopy after the electrode experiences 120 consecutive voltammetric cycles to various potential limits. Distinct structural damage emerges due to [EMI] when the negative potential reaches -1.7 V, and those due to [TFSI] arise when the positive potential reaches 1.7 V vs. RHE. Judging from the peak broadenings, [EMI] is more detrimental than [TFSI]. When the voltage window ΔU is set as less than or equal to 2.8 V, both electrode potentials are within the two intercalation limits, little or no decay is observed in 10(4) charge/discharge cycles. When ΔU is 3.4 V, the positive potential exceeds the upper limit, but the negative potential stays within the lower limit, the cell capacitance decreases moderately. When ΔU increases to 3.8 V, both electrodes suffer from damages because of exceeding the intercalation limits. And the cell capacitance decreases substantially, even leading to a premature failure.

Homologue Pairing in Flies and Mammals: Gene Regulation When Two Are Involved

Directory of Open Access Journals (Sweden)

Manasi S. Apte

2012-01-01

Full Text Available Chromosome pairing is usually discussed in the context of meiosis. Association of homologues in germ cells enables chromosome segregation and is necessary for fertility. A few organisms, such as flies, also pair their entire genomes in somatic cells. Most others, including mammals, display little homologue pairing outside of the germline. Experimental evidence from both flies and mammals suggests that communication between homologues contributes to normal genome regulation. This paper will contrast the role of pairing in transmitting information between homologues in flies and mammals. In mammals, somatic homologue pairing is tightly regulated, occurring at specific loci and in a developmentally regulated fashion. Inappropriate pairing, or loss of normal pairing, is associated with gene misregulation in some disease states. While homologue pairing in flies is capable of influencing gene expression, the significance of this for normal expression remains unknown. The sex chromosomes pose a particularly interesting situation, as females are able to pair X chromosomes, but males cannot. The contribution of homologue pairing to the biology of the X chromosome will also be discussed.

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.

Ommatidia of blow fly, house fly, and flesh fly: implication of their vision efficiency.

Science.gov (United States)

Sukontason, Kabkaew L; Chaiwong, Tarinee; Piangjai, Somsak; Upakut, Sorawit; Moophayak, Kittikhun; Sukontason, Kom

2008-06-01

This work aims to elucidate the number of ommatidia or facets (the outwardly visible units of each ommatidium) for compound eyes in blow flies [Chrysomya megacephala (F.), Chrysomya rufifacies (Macquart), Chrysomya nigripes (Aubertin), Lucilia cuprina (Wiedemann)], house flies (Musca domestica L.), and flesh flies (Liosarcophaga dux Thomson) by manual counts of the corneal spreads. The head of the fly in each species was soaked in 20% potassium hydroxide solution at room temperature for 7 days, and the clear compound eye was dissected into six small parts, each of which was placed onto a slide and flattened using a coverslip. Images of each part were obtained using a microscope connected to a computer. The printed images of each part were magnified, and the total number of ommatidia per eye was manually counted. For males, the mean number of ommatidia was statistically different among all flies examined: L. dux (6,032) > C. rufifacies (5,356) > C. nigripes (4,798) > C. megacephala (4,376) > L. cuprina (3,665) > M. domestica (3,484). Likewise, the mean number of facets in females was statistically different: L. dux (6,086) > C. megacephala (5,641) > C. rufifacies (5,208) > C. nigripes (4,774) > L. cuprina (3,608) > M. domestica (3433). Scanning electron microscopy analysis of adult flies revealed the sexual dimorphism in the compound eye. Male C. megacephala had large ommatidia in the upper two thirds part and small ommatidia in the lower one third part, whereas only small ommatidia were detected in females. Dense postulate appearance was detected in the external surface of the corneal lens of the ommatidia of C. megacephala, C. rufifacies, and C. nigripes, while a mix of dense postulate appearance and variable groove array length was detected in L. cuprina and M. domestica. The probable functions of ommatidia are discussed with reference to other literature.

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.

Junction region of EWS-FLI1 fusion protein has a dominant negative effect in Ewing's sarcoma in vitro.

Science.gov (United States)

Jully, Babu; Vijayalakshmi, Ramshankar; Gopal, Gopisetty; Sabitha, Kesavan; Rajkumar, Thangarajan

2012-11-12

Ewing's sarcoma is a malignancy characterized by a specific 11:22 chromosomal translocation which generates a novel EWS-FLI1 fusion protein functioning as an aberrant transcription factor. In the present study, we have further characterized the junction region of the EWS-FLI1 fusion protein. In-silico model of EWS-FLI1 fusion protein was analysed for ligand binding sites, and a putative region (amino acid (aa) 251-343 of the type 1 fusion protein) in the vicinity of the fusion junction was cloned and expressed using bacterial expression. The recombinant protein was characterized by Circular Dichroism (CD). We then expressed aa 251-280 ectopically in Ewing's sarcoma cell-line and its effect on cell proliferation, tumorigenicity and expression of EWS-FLI1 target genes were analysed. Our modelling analysis indicated that Junction region (aa 251-343) encompasses potential ligand biding sites in the EWS-FLI1 protein and when expressed in bacteria was present as soluble form. Ectopically expressing this region in Ewing's sarcoma cells inhibited tumorigenicity, and EWS-FLI1 target genes indicating a dominant negative biological effect. Junction region can be exploited further as target for drug development in future to specifically target EWS-FLI1 in Ewing's Sarcoma.

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.

The Fly Printer - Extended

DEFF Research Database (Denmark)

Beloff, Laura; Klaus, Malena

2016-01-01

Artist talk / Work-in-progress What is the purpose of a machine or an artifact, like the Fly Printer, that is dislocated, that produces images that have no meaning, no instrumentality, that depict nothing in the world? The biological and the cultural are reunited in this apparatus as a possibility...... to break through a common way of depicting the world, trying to find different surfaces and using strange apparatus to insist in the interstice of visibility. The Fly Printer is a printing apparatus in a form of a closed environment that contains a flock of fruit flies. The flies eat special food...... that is prepared for them that is mixed with laser jet printer inks. The flies digest the food and gradually print different color dots onto the paper that is placed under the fly habitat. In the Fly Printer biological organisms are used for replacing a standard part of our common printer technology. The work...

Iso-Oriented NaTi2(PO4)3 Mesocrystals as Anode Material for High-Energy and Long-Durability Sodium-Ion Capacitor.

Science.gov (United States)

Wei, Tongye; Yang, Gongzheng; Wang, Chengxin

2017-09-20

Sodium-ion capacitors (SIC) combine the merits of both high-energy batteries and high-power electrochemical capacitors as well as the low cost and high safety. However, they are also known to suffer from the severe deficiency of suitable electrode materials with high initial Coulombic efficiency (ICE) and kinetic balance between both electrodes. Herein, we report a facile solvothermal synthesis of NaTi 2 (PO 4 ) 3 nanocages constructed by iso-oriented tiny nanocrystals with a mesoporous architecture. It is notable that the NaTi 2 (PO 4 ) 3 mesocrystals exhibit a large ICE of 94%, outstanding rate capability (98 mA h g -1 at 10 C), and long cycling life (over 77% capacity retention after 10 000 cycles) in half cells, all of which are in favor to be utilized into a full cell. When assembled with commercial activated carbon to an SIC, the system delivers an energy density of 56 Wh kg -1 at a power density of 39 W kg -1 . Even at a high current rate of 5 A g -1 (corresponds to finish a full charge/discharge process in 2 min), the SIC still works well after 20 000 cycles without obvious capacity degradation. With the merits of impressive energy/power densities and longevity, the obtained hybrid capacitor should be a promising device for highly efficient energy storage systems.

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.

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

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.

The plasma membrane as a capacitor for energy and metabolism

Science.gov (United States)

Ray, Supriyo; Kassan, Adam; Busija, Anna R.; Rangamani, Padmini

2016-01-01

When considering which components of the cell are the most critical to function and physiology, we naturally focus on the nucleus, the mitochondria that regulate energy and apoptotic signaling, or other organelles such as the endoplasmic reticulum, Golgi, ribosomes, etc. Few people will suggest that the membrane is the most critical element of a cell in terms of function and physiology. Those that consider the membrane critical will point to its obvious barrier function regulated by the lipid bilayer and numerous ion channels that regulate homeostatic gradients. What becomes evident upon closer inspection is that not all membranes are created equal and that there are lipid-rich microdomains that serve as platforms of signaling and a means of communication with the intracellular environment. In this review, we explore the evolution of membranes, focus on lipid-rich microdomains, and advance the novel concept that membranes serve as “capacitors for energy and metabolism.” Within this framework, the membrane then is the primary and critical regulator of stress and disease adaptation of the cell. PMID:26771520

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...

EWS/FLI mediates transcriptional repression via NKX2.2 during oncogenic transformation in Ewing's sarcoma.

Directory of Open Access Journals (Sweden)

Leah A Owen

2008-04-01

Full Text Available EWS/FLI is a master regulator of Ewing's sarcoma formation. Gene expression studies in A673 Ewing's sarcoma cells have demonstrated that EWS/FLI downregulates more genes than it upregulates, suggesting that EWS/FLI, and/or its targets, function as transcriptional repressors. One critical EWS/FLI target, NKX2.2, is a transcription factor that contains both transcriptional activation and transcriptional repression domains, raising the possibility that it mediates portions of the EWS/FLI transcriptional signature. We now report that microarray analysis demonstrated that the transcriptional profile of NKX2.2 consists solely of downregulated genes, and overlaps with the EWS/FLI downregulated signature, suggesting that NKX2.2 mediates oncogenic transformation via transcriptional repression. Structure-function analysis revealed that the DNA binding and repressor domains in NKX2.2 are required for oncogenesis in Ewing's sarcoma cells, while the transcriptional activation domain is completely dispensable. Furthermore, blockade of TLE or HDAC function, two protein families thought to mediate the repressive function of NKX2.2, inhibited the transformed phenotype and reversed the NKX2.2 transcriptional profile in Ewing's sarcoma cells. Whole genome localization studies (ChIP-chip revealed that a significant portion of the NKX2.2-repressed gene expression signature was directly mediated by NKX2.2 binding. These data demonstrate that the transcriptional repressive function of NKX2.2 is necessary, and sufficient, for the oncogenic phenotype of Ewing's sarcoma, and suggest a therapeutic approach to this disease.

Optimization of Design Parameters and Operating Conditions of Electrochemical Capacitors for High Energy and Power Performance

Science.gov (United States)

Ike, Innocent S.; Sigalas, Iakovos; Iyuke, Sunny E.

2017-03-01

Theoretical expressions for performance parameters of different electrochemical capacitors (ECs) have been optimized by solving them using MATLAB scripts as well as via the MATLAB R2014a optimization toolbox. The performance of the different kinds of ECs under given conditions was compared using theoretical equations and simulations of various models based on the conditions of device components, using optimal values for the coefficient associated with the battery-kind material ( K BMopt) and the constant associated with the electrolyte material ( K Eopt), as well as our symmetric electric double-layer capacitor (EDLC) experimental data. Estimation of performance parameters was possible based on values for the mass ratio of electrodes, operating potential range ratio, and specific capacitance of electrolyte. The performance of asymmetric ECs with suitable electrode mass and operating potential range ratios using aqueous or organic electrolyte at appropriate operating potential range and specific capacitance was 2.2 and 5.56 times greater, respectively, than for the symmetric EDLC and asymmetric EC using the same aqueous electrolyte, respectively. This enhancement was accompanied by reduced cell mass and volume. Also, the storable and deliverable energies of the asymmetric EC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 12.9 times greater than those of the symmetric EDLC using aqueous electrolyte, again with reduced cell mass and volume. The storable energy, energy density, and power density of the asymmetric EDLC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 5.56 times higher than for a similar symmetric EDLC using aqueous electrolyte, with cell mass and volume reduced by a factor of 1.77. Also, the asymmetric EDLC with the same type of electrode and suitable electrode mass ratio, working potential range ratio, and proper organic electrolyte

Carbon nanofibers (CNFs) supported cobalt- nickel sulfide (CoNi2S4) nanoparticles hybrid anode for high performance lithium ion capacitor.

Science.gov (United States)

Jagadale, Ajay; Zhou, Xuan; Blaisdell, Douglas; Yang, Sen

2018-01-25

Lithium ion capacitors possess an ability to bridge the gap between lithium ion battery and supercapacitor. The main concern of fabricating lithium ion capacitors is poor rate capability and cyclic stability of the anode material which uses sluggish faradaic reactions to store an electric charge. Herein, we have fabricated high performance hybrid anode material based on carbon nanofibers (CNFs) and cobalt-nickel sulfide (CoNi 2 S 4 ) nanoparticles via simple electrospinning and electrodeposition methods. Porous and high conducting CNF@CoNi 2 S 4 electrode acts as an expressway network for electronic and ionic diffusion during charging-discharging processes. The effect of anode to cathode mass ratio on the performance has been studied by fabricating lithium ion capacitors with different mass ratios. The surface controlled contribution of CNF@CoNi 2 S 4 electrode was 73% which demonstrates its excellent rate capability. Lithium ion capacitor fabricated with CNF@CoNi 2 S 4 to AC mass ratio of 1:2.6 showed excellent energy density of 85.4 Wh kg -1 with the power density of 150 W kg -1 . Also, even at the high power density of 15 kW kg -1 , the cell provided the energy density of 35 Wh kg -1 . This work offers a new strategy for designing high-performance hybrid anode with the combination of simple and cost effective approaches.

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

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

KAUST Repository

Li, Ping; Jiang, Li Jun; Bagci, Hakan

2017-01-01

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

The onion fly

International Nuclear Information System (INIS)

Loosjes, M.

1990-01-01

This paper describes the origin, practical application, problems in application and prospects of control of the onion fly, Delia antiqua (Diptera: Anthomyiidae), in the Netherlands by the Sterile Insect Technique (SIT). The larva of the onion fly is a severe pest in onions in temperate regions. Development of resistance of the onion fly against insecticides caused research on the SIT to be started by the Dutch Government in 1965. This research was on mass-rearing, long-term storage of pupae, sterilization, and release and ratio assessment techniques. By 1979 sufficient information had been turned over to any interested private company. In the case of the onion fly the SIT can be applied like a control treatment instead of chemical control to individual onion fields. This is due to the limited dispersal activity of the flies and the scattered distribution of onion fields in the Netherlands, with 5-10% of the onion growing areas planted with onions

A zebrafish transgenic model of Ewing’s sarcoma reveals conserved mediators of EWS-FLI1 tumorigenesis

Directory of Open Access Journals (Sweden)

Stefanie W. Leacock

2012-01-01

Ewing’s sarcoma, a malignant bone tumor of children and young adults, is a member of the small-round-blue-cell tumor family. Ewing’s sarcoma family tumors (ESFTs, which include peripheral primitive neuroectodermal tumors (PNETs, are characterized by chromosomal translocations that generate fusions between the EWS gene and ETS-family transcription factors, most commonly FLI1. The EWS-FLI1 fusion oncoprotein represents an attractive therapeutic target for treatment of Ewing’s sarcoma. The cell of origin of ESFT and the molecular mechanisms by which EWS-FLI1 mediates tumorigenesis remain unknown, and few animal models of Ewing’s sarcoma exist. Here, we report the use of zebrafish as a vertebrate model of EWS-FLI1 function and tumorigenesis. Mosaic expression of the human EWS-FLI1 fusion protein in zebrafish caused the development of tumors with histology strongly resembling that of human Ewing’s sarcoma. The incidence of tumors increased in a p53 mutant background, suggesting that the p53 pathway suppresses EWS-FLI1-driven tumorigenesis. Gene expression profiling of the zebrafish tumors defined a set of genes that might be regulated by EWS-FLI1, including the zebrafish ortholog of a crucial EWS-FLI1 target gene in humans. Stable zebrafish transgenic lines expressing EWS-FLI1 under the control of the heat-shock promoter exhibit altered embryonic development and defective convergence and extension, suggesting that EWS-FLI1 interacts with conserved developmental pathways. These results indicate that functional targets of EWS-FLI1 that mediate tumorigenesis are conserved from zebrafish to human and provide a novel context in which to study the function of this fusion oncogene.

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

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)

Junction region of EWS-FLI1 fusion protein has a dominant negative effect in Ewing’s Sarcoma in vitro

International Nuclear Information System (INIS)

Jully, Babu; Vijayalakshmi, Ramshankar; Gopal, Gopisetty; Sabitha, Kesavan; Rajkumar, Thangarajan

2012-01-01

Ewing’s sarcoma is a malignancy characterized by a specific 11:22 chromosomal translocation which generates a novel EWS-FLI1 fusion protein functioning as an aberrant transcription factor. In the present study, we have further characterized the junction region of the EWS-FLI1 fusion protein. In-silico model of EWS-FLI1 fusion protein was analysed for ligand binding sites, and a putative region (amino acid (aa) 251–343 of the type 1 fusion protein) in the vicinity of the fusion junction was cloned and expressed using bacterial expression. The recombinant protein was characterized by Circular Dichroism (CD). We then expressed aa 251–280 ectopically in Ewing’s sarcoma cell-line and its effect on cell proliferation, tumorigenicity and expression of EWS-FLI1 target genes were analysed. Our modelling analysis indicated that Junction region (aa 251–343) encompasses potential ligand biding sites in the EWS-FLI1 protein and when expressed in bacteria was present as soluble form. Ectopically expressing this region in Ewing’s sarcoma cells inhibited tumorigenicity, and EWS-FLI1 target genes indicating a dominant negative biological effect. Junction region can be exploited further as target for drug development in future to specifically target EWS-FLI1 in Ewing’s Sarcoma

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...

Modelling and control of three-phase grid-connected power supply with small DC-link capacitor for electrolysers

DEFF Research Database (Denmark)

Török, Lajos; Máthé, Lászlo; Nielsen, Carsten Karup

2016-01-01

These days electrolyzers are becoming more and more interesting due to the high demand for energy storage in form of hydrogen for renewable power generation using fuel cells. The design of a power supply for such a system is complex especially when the DC-link capacitance is reduced....... By substituting the complex switching model of the power supply with a simplified one, the system dynamics can be better observed. The resonances caused by the small DC link capacitor and grid side inductance can be easier analyzed. A feed forward compensation method is proposed based on the simplified model......-forward compensation signal is created, canceling in such a way the resonance introduced by the grid inductance and the DC-link capacitor from the feed-forward loop. The theoretical work has been validated through experiments on a 5 kW DC power supply used for electrolyser application....

Mutagenicity and genotoxicity of coal fly ash water leachate.

Science.gov (United States)

Chakraborty, Rajarshi; Mukherjee, Anita

2009-03-01

Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to storage or ash ponds located near power stations. This has lain to waste thousands of hectares of land all over the world. Since leaching is often the cause of off-site contamination and pathway of introduction into the human environment, a study on the genotoxic effects of fly ash leachate is essential. Leachate prepared from the fly ash sample was analyzed for metal content, and tested for mutagenicity and genotoxicity. Analyses of metals show predominance of the metals-sodium, silicon, potassium, calcium, magnesium, iron, manganese, zinc, and sulphate. The Ames Salmonella mutagenicity assay, a short-term bacterial reverse mutation assay, was conducted on two-tester strains of Salmonella typhimurium strains TA97a and TA102. For genotoxicity, the alkaline version of comet assay on fly ash leachate was carried in vitro on human blood cells and in vivo on Nicotiana plants. The leachate was directly mutagenic and induced significant (Ppercentage (%), tail length (mum), and olive tail moment (arbitrary units). Our results indicate that leachate from fly ash dumpsites has the genotoxic potential and may lead to adverse effects on vegetation and on the health of exposed human populations.

The repellency of lemongrass oil against stable flies, tested using video tracking

Science.gov (United States)

Baldacchino, Frédéric; Tramut, Coline; Salem, Ali; Liénard, Emmanuel; Delétré, Emilie; Franc, Michel; Martin, Thibaud; Duvallet, Gérard; Jay-Robert, Pierre

2013-01-01

Lemongrass oil (Cymbopogon citratus) is an effective repellent against mosquitoes (Diptera: Culicidae) and house flies (Diptera: Muscidae). In this study, its effectiveness was assessed on stable flies (Diptera: Muscidae) in laboratory conditions. First, we demonstrated that lemongrass oil is an active substance for antennal olfactory receptor cells of Stomoxys calcitrans as indicated by a significant increase in the electroantennogram responses to increasing doses of lemongrass oil. Feeding-choice tests in a flight cage with stable flies having access to two blood-soaked sanitary pads, one of which was treated with lemongrass oil, showed that stable flies (n = 24) spent significantly more time in the untreated zone (median value = 218.4 s) than in the treated zone (median value = 63.7 s). No stable flies fed on the treated pad, whereas nine fed on the untreated pad. These results suggest that lemongrass oil could be used as an effective repellent against stable flies. Additional studies to confirm its spatial repellent and feeding deterrent effects are warranted. PMID:23759542

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.

The Diversity of Yellow-Related Proteins in Sand Flies (Diptera: Psychodidae.

Directory of Open Access Journals (Sweden)

Michal Sima

Full Text Available Yellow-related proteins (YRPs present in sand fly saliva act as affinity binders of bioamines, and help the fly to complete a bloodmeal by scavenging the physiological signals of damaged cells. They are also the main antigens in sand fly saliva and their recombinant form is used as a marker of host exposure to sand flies. Moreover, several salivary proteins and plasmids coding these proteins induce strong immune response in hosts bitten by sand flies and are being used to design protecting vaccines against Leishmania parasites. In this study, thirty two 3D models of different yellow-related proteins from thirteen sand fly species of two genera were constructed based on the known protein structure from Lutzomyia longipalpis. We also studied evolutionary relationships among species based on protein sequences as well as sequence and structural variability of their ligand-binding site. All of these 33 sand fly YRPs shared a similar structure, including a unique tunnel that connects the ligand-binding site with the solvent by two independent paths. However, intraspecific modifications found among these proteins affects the charges of the entrances to the tunnel, the length of the tunnel and its hydrophobicity. We suggest that these structural and sequential differences influence the ligand-binding abilities of these proteins and provide sand flies with a greater number of YRP paralogs with more nuanced answers to bioamines. All these characteristics allow us to better evaluate these proteins with respect to their potential use as part of anti-Leishmania vaccines or as an antigen to measure host exposure to sand flies.

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....

Thin PZT-Based Ferroelectric Capacitors on Flexible Silicon for Nonvolatile Memory Applications

KAUST Repository

Ghoneim, Mohamed T.

2015-04-24

A flexible version of traditional thin lead zirconium titanate ((Pb1.1Zr0.48Ti0.52O3)-(PZT)) based ferroelectric random access memory (FeRAM) on silicon shows record performance in flexible arena. The thin PZT layer requires lower operational voltages to achieve coercive electric fields, reduces the sol-gel coating cycles required (i.e., more cost-effective), and, fabrication wise, is more suitable for further scaling of lateral dimensions to the nano-scale due to the larger feature size-to-depth aspect ratio (critical for ultra-high density non-volatile memory applications). Utilizing the inverse proportionality between substrate\\'s thickness and its flexibility, traditional PZT based FeRAM on silicon is transformed through a transfer-less manufacturable process into a flexible form that matches organic electronics\\' flexibility while preserving the superior performance of silicon CMOS electronics. Each memory cell in a FeRAM array consists of two main elements; a select/access transistor, and a storage ferroelectric capacitor. Flexible transistors on silicon have already been reported. In this work, we focus on the storage ferroelectric capacitors, and report, for the first time, its performance after transformation into a flexible version, and assess its key memory parameters while bent at 0.5 cm minimum bending radius.

Temperature Effects on Olive Fruit Fly Infestation in the FlySim Cellular Automata Model

Science.gov (United States)

Bruno, Vincenzo; Baldacchini, Valerio; di Gregorio, Salvatore

FlySim is a Cellular Automata model developed for simulating infestation of olive fruit flies (Bactrocera Oleae) on olive (Olea europaea) groves. The flies move into the groves looking for mature olives where eggs are spawn. This serious agricultural problem is mainly tackled by using chemical agents at the first signs of the infestation, but organic productions with no or few chemicals are strongly requested by the market. Oil made with infested olives is poor in quality, nor olives are suitable for selling in stores. The FlySim model simulates the diffusion of flies looking for mature olives and the growing of flies due to atmospheric conditions. Foreseeing an infestation is the best way to prevent it and to reduce the need of chemicals in agriculture. In this work we investigated the effects of temperature on olive fruit flies and resulting infestation during late spring and summer.