Sample records for voltage dielectrically isolated

  1. Dielectric insulation and high-voltage issues

    CERN Document Server

    Tommasini, D


    Electrical faults are in most cases dramatic events for magnets, due to the large stored energy which is potentially available to be dissipated at the fault location. After a reminder of the principles of electrostatics in Section 1, the basic mechanisms of conduction and breakdown in dielectrics are summarized in Section 2. Section 3 introduces the types and function of the electrical insulation in magnets, and Section 4 its relevant failure mechanisms. Section 5 deals with ageing and, finally, Section 6 gives some principles for testing. Though the School specifically dealt with warm magnets, for completeness some principles of dielectric insulation for superconducting accelerator magnets are briefly summarized in a dedicated appendix.

  2. Voltage-Induced Buckling of Dielectric Films using Fluid Electrodes

    CERN Document Server

    Tavakol, Behrouz


    Accurate and integrable control of different flows within microfluidic channels is crucial to further development of lab-on-a-chip and fully integrated adaptable structures. Here we introduce a flexible microactuator that buckles at a high deformation rate and alters the downstream fluid flow. The microactuator consists of a confined, thin, dielectric film that buckles into the microfluidic channel when exposed to voltage supplied through conductive fluid electrodes. We estimate the critical buckling voltage, and characterize the buckled shape of the actuator. Finally, we investigate the effects of frequency, flow rate, and the pressure differences on the behavior of the buckling structure and the resulting fluid flow. These results demonstrate that the voltage--induced buckling of embedded microstructures using fluid electrodes provides a means for high speed attenuation of microfluidic flow.

  3. A threshold voltage model for high-κgate-dielectric MOSFETs considering fringing-field effect

    Institute of Scientific and Technical Information of China (English)

    Ji Feng; Xu Jing-Ping; Lai Pui-To


    In this paper, a threshold voltage model for high-κgate-dielectric metal-oxide-semiconductor field-effect transistors (MOSFETs) is developed, with more accurate boundary conditions of the gate dielectric derived through a conformal mapping transformation method to consider the fringing-field effects including the influences of high-κgate-dielectric and sidewall spacer. Comparing with similar models, the proposed model can be applied to general situations where the gate dielectric and sidewall spacer can have different dielectric constants. The influences of sidewall spacer and high-κgate dielectric on fringing field distribution of the gate dielectric and thus threshold voltage behaviours of a MOSFET are discussed in detail.

  4. Compact, Lightweight, High Voltage Propellant Isolators Project (United States)

    National Aeronautics and Space Administration — TA&T, Inc. proposes an enabling fabrication process for high voltage isolators required in high power solar electric and nuclear electric propulsion (SEP and...

  5. Compact, Lightweight, High Voltage Propellant Isolators Project (United States)

    National Aeronautics and Space Administration — TA&T, Inc. proposes an enabling fabrication process for high voltage isolators required in high power solar electric and nuclear electric propulsion (SEP and...

  6. Effects of dielectric charging on the output voltage of a capacitive accelerometer (United States)

    Qu, Hao; Yu, Huijun; Zhou, Wu; Peng, Bei; Peng, Peng; He, Xiaoping


    Output voltage drifting observed in one typical capacitive microelectromechanical system (MEMS) accelerometer is discussed in this paper. Dielectric charging effect is located as one of the major determinants of this phenomenon through a combination of experimental and theoretical studies. A theoretical model for the electromechanical effects of the dielectric surface charges within the electrode gap is established to analyze the dielectric charge effect on the output voltage. Observations of output voltage drift against time are fitted to this model in order to estimate the possible dielectric layer thickness. Meanwhile, Auger electron spectroscopy is carried out to analyze the electrode surface material composition and confirms a mixture layer of dielectric SiO2 and Si with a thickness about 5 nm, which is very close to the model estimation. In addition, observation of time-varing output drift in the variable bias voltage experiment indicates the movement of dielectric charge can be controlled by the applied electric field.

  7. Dielectric isolation for power integrated circuits; Isolation dielectrique enterree pour les circuits integres de puissance

    Energy Technology Data Exchange (ETDEWEB)

    Zerrouk, D.


    Considerable efforts have been recently directed towards integrating onto the same chip, sense or protection elements that is low voltage analog and/or digital control circuitry together with high voltage/high current devices. Most of these so called `smart power` devices use either self isolation, junction isolation or Silicon-On-Insulator (SOI) to integrate low voltage elements with vertical power devices. Dielectric isolation is superior to the other isolation techniques such as self isolation or junction isolation. Thesis work consists of the study of the feasibility of a dielectric technology based on the melting and the solidification in a Rapid Thermal Processing furnace (RTP), of thick polysilicon films deposited on oxide. The purpose of this technique is to obtain substrate with localized SOI structures for smart power applications. SOI technology offers significant potential advantages, such as non-occurrence of latch-up in CMOS structures, high packaging density, low parasitic capacitance and the possibility of 3D structures. In addition, SOI technology using thick silicon films (10-100 {mu}m) offers special advantages for high voltage integrated circuits. Several techniques have been developed to form SOI films. Zone melting recrystallization is one of the most promising for localized SOI. The SOI structures have first been analyzed in term of extended defects. N-channel MOSFET`s transistors have also been fabricated in the SOI substrates and electrically characterized (threshold voltages, off-state leakage current, mobilities,...). The SOI transistors exhibit good characteristics, although inferior to witness transistors. The recrystallized silicon films are therefore found to be suitable for the fabrication of SOI devices. (author) 106 refs.

  8. Isolated Fast High-Voltage Switching Circuit (United States)

    Rizzi, Anthony


    Electrically isolated switching circuit supplies pulses at potentials up to 6.5 kV and currents up to 6.5 A, lasting as long as few microseconds. Turn-on time about 40 ns; turn-off time about 3 microseconds. Electrically isolated from control circuitry by means of fiber-optic signal coupling and isolated power supply. Electrical isolation protects both technician and equipment. This and similar circuits useful in such industrial and scientific applications as high-voltage, high-frequency test equipment; electrostatic-discharge test equipment; plasma-laboratory instrumentation; spark chambers; and electromagnetic-interference test equipment.

  9. Note: Galvanic isolated voltage source using a single photodiode. (United States)

    Stoican, O S


    A galvanic isolated voltage source able to provide several volts by using a single photodiode is described. A pulse-modulated laser beam is sent to a photodiode. By using a step-up transformer the amplitude of the variable voltage generated by the photodiode is increased. Adding a rectifier cell the variable voltage is converted back into a dc voltage.

  10. Calculation of Onset Voltage of Sliding Discharge over a Dielectric Barrier

    Directory of Open Access Journals (Sweden)

    Abdel-Salam Mazen


    Full Text Available This paper is aimed at calculating the onset voltage of a sliding discharge established between two electrodes at the upper and bottom surfaces of a dielectric barrier plate; named sliding dielectric barrier discharge (SDBD driven by AC voltage during negative half cycle. The onset voltage is based on the condition of self-sustenance of avalanche growth in the vicinity of the stressed electrode. This calls at first for calculation of the electric field in the vicinity of stressed electrode. The dependency of onset voltage on the thickness and permittivity of the dielectric barrier as well as the thickness of the stressed electrode and the inter-electrode spacing between the stressed and ground electrodes is investigated. The obtained results are discussed in the light of gas discharge physics.

  11. Modeling self-priming circuits for dielectric elastomer generators towards optimum voltage boost (United States)

    Zanini, Plinio; Rossiter, Jonathan; Homer, Martin


    One of the main challenges for the practical implementation of dielectric elastomer generators (DEGs) is supplying high voltages. To address this issue, systems using self-priming circuits (SPCs) — which exploit the DEG voltage swing to increase its supplied voltage — have been used with success. A self-priming circuit consists of a charge pump implemented in parallel with the DEG circuit. At each energy harvesting cycle, the DEG receives a low voltage input and, through an almost constant charge cycle, generates a high voltage output. SPCs receive the high voltage output at the end of the energy harvesting cycle and supply it back as input for the following cycle, using the DEG as a voltage multiplier element. Although rules for designing self-priming circuits for dielectric elastomer generators exist, they have been obtained from intuitive observation of simulation results and lack a solid theoretical foundation. Here we report the development of a mathematical model to predict voltage boost using self-priming circuits. The voltage on the DEG attached to the SPC is described as a function of its initial conditions, circuit parameters/layout, and the DEG capacitance. Our mathematical model has been validated on an existing DEG implementation from the literature, and successfully predicts the voltage boost for each cycle. Furthermore, it allows us to understand the conditions for the boost to exist, and obtain the design rules that maximize the voltage boost.

  12. Electromechanical phase transition in dielectric elastomers under uniaxial tension and electrical voltage (United States)

    Huang, Rui; Suo, Zhigang


    Subject to forces and voltage, a dielectric elastomer may undergo electromechanical phase transition. A phase diagram is constructed for an ideal dielectric elastomer membrane under uniaxial force and voltage, reminiscent of the phase diagram for liquid-vapor transition of a pure substance. We identify a critical point for the electromechanical phase transition. Two states of deformation (thick and thin) may coexist during the phase transition, with the mismatch in lateral stretch accommodated by wrinkling of the membrane in the thin state. The processes of electromechanical phase transition under various conditions are discussed. A reversible cycle is suggested for electromechanical energy conversion using the dielectric elastomer membrane, analogous to the classical Carnot cycle for a heat engine. The amount of energy conversion, however, is limited by failure of the dielectric elastomer due to electrical breakdown. With a particular combination of material properties, the electromechanical energy conversion can be significantly extended by taking advantage of the phase transition without electrical breakdown.

  13. Evaluation of high temperature dielectric films for high voltage power electronic applications (United States)

    Suthar, J. L.; Laghari, J. R.


    Three high temperature films, polyimide, Teflon perfluoroalkoxy and poly-P-xylene, were evaluated for possible use in high voltage power electronic applications, such as in high energy density capacitors, cables and microelectronic circuits. The dielectric properties, including permittivity and dielectric loss, were obtained in the frequency range of 50 Hz to 100 kHz at temperatures up to 200 C. The dielectric strengths at 60 Hz were determined as a function of temperature to 250 C. Confocal laser microscopy was performed to diagnose for voids and microimperfections within the film structure. The results obtained indicate that all films evaluated are capable of maintaining their high voltage properties, with minimal degradation, at temperatures up to 200 C. However, above 200 C, they lose some of their electrical properties. These films may therefore become viable candidates for high voltage power electronic applications at high temperatures.

  14. Voltage-induced pinnacle response in the dynamics of dielectric elastomers (United States)

    Li, Bo; Zhang, Junshi; Chen, Hualing; Li, Dichen


    A dielectric elastomer is capable of large deformation under alternating electromechanical excitation. In this paper, several dynamic properties of a dielectric elastomer are investigated, in particular the effect of strain stiffening. A theoretical model is established that shows that the bias voltage affects the amplitude and the response waveform during vibration, a curve with the shape of a pinnacle. We also describe the underlying physical mechanism by considering the molecular chain length and cross-linking density of the material. A phase portrait is presented that reveals the transitional behavior of the dielectric elastomer as it switches between soft and stiffened vibration states.

  15. Low pull-in voltage electrostatic MEMS switch using liquid dielectric

    KAUST Repository

    Zidan, Mohammed A.


    In this paper, we present an electrostatic MEMS switch with liquids as dielectric to reduce the actuation voltage. The concept is verified by simulating a lateral dual gate switch, where the required pull-in voltage is reduced by more than 8 times after using water as a dielectric, to become as low as 5.36V. The proposed switch is simulated using COMSOL multiphysics using various liquid volumes to study their effect on the switching performance. Finally, we propose the usage of the lateral switch as a single switch XOR logic gate.

  16. Electrical conduction mechanism in bulk ceramic insulators at high voltages until dielectric breakdown (United States)

    Neusel, C.; Jelitto, H.; Schneider, G. A.


    In order to develop and verify a dielectric breakdown model for bulk insulators thicker than 100 μm, the knowledge of the dominating conduction mechanism at high electric fields, or respectively voltages, is necessary. The dielectric breakdown is the electrical failure of an insulator. In some existing breakdown models, ohmic conduction is assumed as dominating conduction mechanism. For verification, the dominating dc conduction mechanism of bulk insulators at room temperature was investigated by applying high voltages up to 70 kV to the insulator until dielectric breakdown occurs. Four conduction models, namely, ohmic, space charge limited, Schottky, and Poole-Frenkel conduction, were employed to identify the dominating conduction mechanism. Comparing the calculated permittivities from the Schottky and Poole-Frenkel coefficients with experimentally measured permittivity, Schottky and Poole-Frenkel conduction can be excluded as dominating conduction mechanism. Based on the current density voltage characteristics (J-V-curve) and the thickness-dependence of the current density, space charge limited conduction (SCLC) was identified to be the dominating conduction mechanism at high voltages leading to dielectric breakdown. As a consequence, breakdown models based on ohmic conduction are not appropriate to explain the breakdown of the investigated bulk insulators. Furthermore, the electrical failure of the examined bulk insulators can only be described correctly by a breakdown model which includes SCLC as conduction mechanism.

  17. Tunable Radiation Response in Hybrid Organic-Inorganic Gate Dielectrics for Low-Voltage Graphene Electronics. (United States)

    Arnold, Heather N; Cress, Cory D; McMorrow, Julian J; Schmucker, Scott W; Sangwan, Vinod K; Jaber-Ansari, Laila; Kumar, Rajan; Puntambekar, Kanan P; Luck, Kyle A; Marks, Tobin J; Hersam, Mark C


    Solution-processed semiconductor and dielectric materials are attractive for future lightweight, low-voltage, flexible electronics, but their response to ionizing radiation environments is not well understood. Here, we investigate the radiation response of graphene field-effect transistors employing multilayer, solution-processed zirconia self-assembled nanodielectrics (Zr-SANDs) with ZrOx as a control. Total ionizing dose (TID) testing is carried out in situ using a vacuum ultraviolet source to a total radiant exposure (RE) of 23.1 μJ/cm(2). The data reveal competing charge density accumulation within and between the individual dielectric layers. Additional measurements of a modified Zr-SAND show that varying individual layer thicknesses within the gate dielectric tuned the TID response. This study thus establishes that the radiation response of graphene electronics can be tailored to achieve a desired radiation sensitivity by incorporating hybrid organic-inorganic gate dielectrics.

  18. Low voltage driven dielectric electro active polymer actuator with integrated piezoelectric transformer based driver

    DEFF Research Database (Denmark)

    Andersen, Thomas; Rødgaard, Martin Schøler; Thomsen, Ole Cornelius


    Today’s Dielectric Electro Active Polymer (DEAP) actuators utilize high voltage (HV) in the range of kilo volts to fully stress the actuator. The requirement of HV is a drawback for the general use in the industry due to safety concerns and HV regulations. In order to avoid the HV interface to DEAP...... actuators, a low voltage solution is developed by integrating the driver electronic into a 110 mm tall cylindrical coreless Push InLastor actuator. To decrease the size of the driver, a piezoelectric transformer (PT) based solution is utilized. The PT is essentially an improved Rosen type PT...... with interleaved sections. Furthermore, the PT is optimized for an input voltage of 24 V with a gain high enough to achieve a DEAP voltage of 2.5 kV. The PT is simulated and verified through measurements on a working prototype. With the adapted hysteretic based control system; output voltage wave forms of both...

  19. Response analysis of dielectric elastomer spherical membrane to harmonic voltage and random pressure (United States)

    Jin, Xiaoling; Wang, Yong; Chen, Michael Z. Q.; Huang, Zhilong


    Spherical membranes consisting of dielectric elastomer play important roles in flexible and stretchable devices, such as flexible actuators, sensors and loudspeakers. Executing various functions of devices depends on the dynamical behaviors of dielectric elastomer spherical membranes to external electrical and/or mechanical excitations. This manuscript concentrates on the random aspect of dielectric elastomer spherical membranes, i.e., the random response to combined excitations of harmonic voltage and random pressure. To analytically evaluate the response statistics of the stretch ratio, a specific transformation and stochastic averaging technique are successively adopted to solve the strongly nonlinear equation with respect to the stretch ratio. The stochastic differential equations for the system first integral and the phase difference between harmonic excitation and response are first derived through this transformation. The Fokker-Planck-Kolmogorov equation with respect to the stationary probability density of the system first integral and the phase difference is obtained. The stationary probability densities and the response statistics of the stretch ratio and its rate of change are then subsequently calculated. The phenomenon of stochastic jumps is found and the stochastic jump bifurcates with the variations of the frequency and the amplitude of the harmonic voltage and the intensity of the random pressure. The efficacy and accuracy of the analytical results are verified by comparing with the results from Monte Carlo simulation. Besides, the reliability of the dielectric elastomer spherical membrane is discussed briefly. The obtained results could provide options in implementing and designing dielectric elastomer structures for dynamic applications.

  20. Evolution of nanosecond surface dielectric barrier discharge for negative polarity of a voltage pulse (United States)

    Soloviev, V. R.; Krivtsov, V. M.; Shcherbanev, S. A.; Starikovskaia, S. M.


    Surface dielectric barrier discharge, initiated by a high-voltage pulse of negative polarity in atmospheric pressure air, is studied numerically and experimentally. At a pulse duration of a few tens of nanoseconds, two waves of optical emission propagate from the high-voltage electrode corresponding to the leading and trailing edges of the high-voltage pulse. It is shown by means of numerical modeling that a glow-like discharge slides along the surface of the dielectric at the leading edge of the pulse, slowing down on the plateau of the pulse. When the trailing edge of the pulse arrives to the high-voltage electrode, a second discharge starts and propagates in the same direction. The difference is that the discharge corresponding to the trailing edge is not diffuse and demonstrates a well-pronounced streamer-like shape. The 2D (in numerical modeling) streamer propagates above the dielectric surface, leaving a gap of about 0.05 mm between the streamer and the surface. The calculated and experimentally measured emission picture, waveform of the electrical current, and deposited energy, qualitatively coincide. The sensitivity of the numerical solution to unknown physical parameters of the model is discussed.

  1. High-voltage atmospheric breakdown across intervening rutile dielectrics.

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, Kenneth Martin; Simpson, Sean; Coats, Rebecca Sue; Jorgenson, Roy Eberhardt; Hjalmarson, Harold Paul; Pasik, Michael Francis


    This report documents work conducted in FY13 on electrical discharge experiments performed to develop predictive computational models of the fundamental processes of surface breakdown in the vicinity of high-permittivity material interfaces. Further, experiments were conducted to determine if free carrier electrons could be excited into the conduction band thus lowering the effective breakdown voltage when UV photons (4.66 eV) from a high energy pulsed laser were incident on the rutile sample. This report documents the numerical approach, the experimental setup, and summarizes the data and simulations. Lastly, it describes the path forward and challenges that must be overcome in order to improve future experiments for characterizing the breakdown behavior for rutile.

  2. Sigma-pi molecular dielectric multilayers for low-voltage organic thin-film transistors. (United States)

    Yoon, Myung-Han; Facchetti, Antonio; Marks, Tobin J


    Very thin (2.3-5.5 nm) self-assembled organic dielectric multilayers have been integrated into organic thin-film transistor structures to achieve sub-1-V operating characteristics. These new dielectrics are fabricated by means of layer-by-layer solution phase deposition of molecular silicon precursors, resulting in smooth, nanostructurally well defined, strongly adherent, thermally stable, virtually pinhole-free, organosiloxane thin films having exceptionally large electrical capacitances (up to approximately 2,500, excellent insulating properties (leakage current densities as low as 10(-9), and single-layer dielectric constant (k)of approximately 16. These 3D self-assembled multilayers enable organic thin-film transistor function at very low source-drain, gate, and threshold voltages (organic semiconductors.

  3. Capacitance-voltage analysis of a high-k dielectric on silicon

    Institute of Scientific and Technical Information of China (English)

    Davinder Rathee; Sandeep K. Arya; Mukesh Kumar


    Device characteristics of TiO2 gate dielectrics deposited by a sol-gel method and DC sputtering method on a P-type silicon wafer are reported.Metal-oxide-semiconductor capacitors with Al as the top electrode were fabricated to study the electrical properties of TiO2 films.The films were physically characterized by using X-ray diffraction,a capacitor voltage measurement,scanning electron microscopy,and by spectroscopy ellipsometry.The XRD and DST-TG indicate the presence of an anatase TiO2 phase in the film.Films deposited at higher temperatures showed better crystallinity.The dielectric constant calculated using the capacitance voltage measurement was found to be 18 and 73 for sputtering and sol-gel samples respectively.The refractive indices of the films were found to be 2.16 for sputtering and 2.42 for sol-gel samples.

  4. Corrosion of Copper and Oxidation of Dielectric Liquids in High Voltage Transformers


    Tronstad, Ingvild


    Breakdowns in high voltage transformers are of major concern. It is therefore a goal to prevent this from happening. Chemical degradation (e.g. oxidation, hydrolysis and corrosion) of the insulation systems and windings and formation of deposits are some of the most important causes of breakdowns in oil-paper insulated transformers.Several of the methods for studying the oxidation stability of dielectric liquids are time consuming and involve harsh conditions, far from the conditions in the t...

  5. Modeling of dielectric barrier discharge excimer lamp excited by mono polar voltage pulses (United States)

    Akashi, Haruaki; Oda, Akinori; Sakai, Yosuke


    Filametal discharges in Dielectric Barrier Discharge (DBD) excimer lamp excited by mono polar voltage pulses has been simulated using two dimensional fluid model. And the differences of the filament discharges formations between mono polar case and bipolar case [1] have been examined. Xe gas was used and its pressure is 300Torr. Simulated region is 1cm (gap length) x 3cm (radial length). Periodical boundary conditions are assumed for the radial direction boundaries. The both electrodes are covered with dielectrics and their thickness is 0.2cm. Applied voltage is 5kV trapezoid shape with 50% duty ratio waveform and its repetition rate is 200kpps. First a small amount of electron-ion pair is provided in the middle of the gap for initial condition. Then the voltage starts to apply. In the case of bipolar excitation, the discharge starts from one filament (streamer discharge), and finally, 5 filaments are obtained self-consistently. In the case of mono polar case, as first, similar to bipolar case, the discharge starts from one filament, however, only 3 filaments have been obtained. This result is similar to that of 100kHz bipolar voltage case. [1] H. Akashi et al, IEEE Trans. Plasma Science, Vol.33, No.2 (2005) pp.308-309

  6. Volume Diffuse Dielectric Barrier Discharge Plasma Produced by Nanosecond High Voltage Pulse in Airflow

    Institute of Scientific and Technical Information of China (English)

    QI Haicheng; GAO Wei; FAN Zhihui; LIU Yidi; REN Chunsheng


    Volume diffuse dielectric barrier discharge (DBD) plasma is produced in subsonic airflow by nanosecond high-voltage pulse power supply with a plate-to-plate discharge cell at 6 mm air gap length.The discharge images,optical emission spectra (OES),the applied voltage and current waveforms of the discharge at the changed airflow rates are obtained.When airflow rate is increased,the transition of the discharge mode and the variations of discharge intensity,breakdown characteristics and the temperature of the discharge plasma are investigated.The results show that the discharge becomes more diffuse,discharge intensity is decreased accompanied by the increased breakdown voltage and time lag,and the temperature of the discharge plasma reduces when airflow of small vclocity is introduced into the discharge gap.These phenomena are because that the airflow changes the spatial distribution of the heat and the space charge in the discharge gap.

  7. Volume Diffuse Dielectric Barrier Discharge Plasma Produced by Nanosecond High Voltage Pulse in Airflow (United States)

    Qi, Haicheng; Gao, Wei; Fan, Zhihui; Liu, Yidi; Ren, Chunsheng


    Volume diffuse dielectric barrier discharge (DBD) plasma is produced in subsonic airflow by nanosecond high-voltage pulse power supply with a plate-to-plate discharge cell at 6 mm air gap length. The discharge images, optical emission spectra (OES), the applied voltage and current waveforms of the discharge at the changed airflow rates are obtained. When airflow rate is increased, the transition of the discharge mode and the variations of discharge intensity, breakdown characteristics and the temperature of the discharge plasma are investigated. The results show that the discharge becomes more diffuse, discharge intensity is decreased accompanied by the increased breakdown voltage and time lag, and the temperature of the discharge plasma reduces when airflow of small velocity is introduced into the discharge gap. These phenomena are because that the airflow changes the spatial distribution of the heat and the space charge in the discharge gap. supported by National Natural Science Foundation of China (No. 51437002)

  8. Low-voltage Organic Thin Film Transistors (OTFTs) with Solution-processed High-k Dielectric cum Interface Engineering (United States)

    Su, Yaorong

    Although impressive progress has been made in improving the performance of organic thin film transistors (OTFTs), the high operation voltage resulting from the low gate areal capacitance of traditional SiO 2 remains a severe limitation that hinders OTFTs' development in practical applications. In this regard, developing new materials with high- k characteristics at low cost is of great scientific and technological importance in the area of both academia and industry. In this thesis, we first describe a simple solution-based method to fabricate a high-k bilayer Al2Oy/TiOx (ATO) dielectric system at low temperature. Then the dielectric properties of the ATO are characterized and discussed in detail. Furthermore, by employing the high-k ATO as gate dielectric, low-voltage copper phthalocyanine (CuPc) based OTFTs are successfully developed. Interestingly, the obtained low-voltage CuPc TFT exhibits outstanding electrical performance, which is even higher than the device fabricated on traditional low-k SiO2. The above results seem to be contradictory to the reported results due to the fact that high-k usually shows adverse effect on the device performance. This abnormal phenomenon is then studied in detail. Characterization on the initial growth shows that the CuPc molecules assemble in a "rod-like" nano crystal with interconnected network on ATO, which probably promotes the charge carrier transport, whereas, they form isolated small islands with amorphous structure on SiO2. In addition, a better metal/organic contact is observed on ATO, which benefits the charge carrier injection. Our studies suggest that the low-temperature, solution-processed high-k ATO is a promising candidate for fabrication of high-performance, low-voltage OTFTs. Furthermore, it is well known that the properties of the dielectric/semiconductor and electrode/semiconductor interfaces are crucial in controlling the electrical properties of OTFTs. Hence, investigation the effects of interfaces

  9. Wafer-scale solution-derived molecular gate dielectrics for low-voltage graphene electronics

    Energy Technology Data Exchange (ETDEWEB)

    Sangwan, Vinod K.; Jariwala, Deep; McMorrow, Julian J.; He, Jianting; Lauhon, Lincoln J. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Everaerts, Ken [Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Grayson, Matthew [Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208 (United States); Marks, Tobin J., E-mail:, E-mail:; Hersam, Mark C., E-mail:, E-mail: [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)


    Graphene field-effect transistors are integrated with solution-processed multilayer hybrid organic-inorganic self-assembled nanodielectrics (SANDs). The resulting devices exhibit low-operating voltage (2 V), negligible hysteresis, current saturation with intrinsic gain >1.0 in vacuum (pressure < 2 × 10{sup −5} Torr), and overall improved performance compared to control devices on conventional SiO{sub 2} gate dielectrics. Statistical analysis of the field-effect mobility and residual carrier concentration demonstrate high spatial uniformity of the dielectric interfacial properties and graphene transistor characteristics over full 3 in. wafers. This work thus establishes SANDs as an effective platform for large-area, high-performance graphene electronics.

  10. Wafer-scale solution-derived molecular gate dielectrics for low-voltage graphene electronics (United States)

    Sangwan, Vinod K.; Jariwala, Deep; Everaerts, Ken; McMorrow, Julian J.; He, Jianting; Grayson, Matthew; Lauhon, Lincoln J.; Marks, Tobin J.; Hersam, Mark C.


    Graphene field-effect transistors are integrated with solution-processed multilayer hybrid organic-inorganic self-assembled nanodielectrics (SANDs). The resulting devices exhibit low-operating voltage (2 V), negligible hysteresis, current saturation with intrinsic gain >1.0 in vacuum (pressure < 2 × 10-5 Torr), and overall improved performance compared to control devices on conventional SiO2 gate dielectrics. Statistical analysis of the field-effect mobility and residual carrier concentration demonstrate high spatial uniformity of the dielectric interfacial properties and graphene transistor characteristics over full 3 in. wafers. This work thus establishes SANDs as an effective platform for large-area, high-performance graphene electronics.

  11. Active vibration isolation with a dielectric elastomer stack actuator (United States)

    Kaal, William; Bartel, Torsten; Herold, Sven


    This work presents the development, simulation and experimental investigation of a demonstrator for active vibration isolation with dielectric elastomers (DEs). The electromechanical behavior of the developed DE stack actuator is first characterized experimentally and a suitable simulation model is parametrized accordingly. The potential of the actuator for active vibration isolation is shown in a specially designed single axis test rig. The influence of different control strategies on the transmission behavior from the excited base to the mass is studied. A special aspect of the control strategy is the compensation of the specific nonlinearities. The analysis proves the potential of DE actuators for active vibration isolation purposes. The presented broadband active isolation could enable the use of DEs in various technical fields of application.

  12. Primary Paralleled Isolated Boost Converter with Extended Operating Voltage Range

    DEFF Research Database (Denmark)

    Hernandez Botella, Juan Carlos; Sen, Gökhan; Mira Albert, Maria del Carmen


    Applications requiring wide input and output voltage range cannot often be satisfied by using buck or boost derived topologies. Primary paralleled isolated boost converter (PPIBC) [1]-[2] is a high efficiency boost derived topology. This paper proposes a new operation mode for extending the input...

  13. A Novel Electrical Insulating Material for 275 kV High-Voltage HTS Cable with Low Dielectric Loss (United States)

    Hayakawa, N.; Nishimachi, S.; Maruyama, O.; Ohkuma, T.; Liu, J.; Yagi, M.


    In the case of high temperature superconducting (HTS) power transmission cables at high voltage operation, the electrical insulation technique in consideration of the dielectric loss reduction becomes crucial. In this paper, we focused on a Tyvek/polyethylene (PE) sheet, instead of the conventional polypropylene laminated paper (PPLP). We obtained the dielectric characteristics (epsilonr, tanδ) and partial discharge inception strength (PDIE) of PPLP, Tyvek and Tyvek/PE. We pointed out that the dielectric loss of 275 kV HTS cable with Tyvek/PE insulation will be reduced to 21 % of that with PPLP, and the total electrical loss including the AC loss will be reduced to 41 %.

  14. Low-voltage bendable pentacene thin-film transistor with stainless steel substrate and polystyrene-coated hafnium silicate dielectric. (United States)

    Yun, Dong-Jin; Lee, Seunghyup; Yong, Kijung; Rhee, Shi-Woo


    The hafnium silicate and aluminum oxide high-k dielectrics were deposited on stainless steel substrate using atomic layer deposition process and octadecyltrichlorosilane (OTS) and polystyrene (PS) were treated improve crystallinity of pentacene grown on them. Besides, the effects of the pentacene deposition condition on the morphologies, crystallinities and electrical properties of pentacene were characterized. Therefore, the surface treatment condition on dielectric and pentacene deposition conditions were optimized. The pentacene grown on polystyrene coated high-k dielectric at low deposition rate and temperature (0.2-0.3 Å/s and R.T.) showed the largest grain size (0.8-1.0 μm) and highest crystallinity among pentacenes deposited various deposition conditions, and the pentacene TFT with polystyrene coated high-k dielectric showed excellent device-performance. To decrease threshold voltage of pentacene TFT, the polystyrene-thickness on high-k dielectric was controlled using different concentration of polystyrene solution. As the polystyrene-thickness on hafnium silicate decreases, the dielectric constant of polystyrene/hafnium silicate increases, while the crystallinity of pentacene grown on polystyrene/hafnium silicate did not change. Using low-thickness polystyrene coated hafnium silicate dielectric, the high-performance and low voltage operating (1 × 10(4)) and complementary inverter (DC gains, ~20) could be fabricated.

  15. Vibroacoustic modeling of an acoustic resonator tuned by dielectric elastomer membrane with voltage control (United States)

    Yu, Xiang; Lu, Zhenbo; Cheng, Li; Cui, Fangsen


    This paper investigates the acoustic properties of a duct resonator tuned by an electro-active membrane. The resonator takes the form of a side-branch cavity which is attached to a rigid duct and covered by a pre-stretched Dielectric Elastomer (DE) in the neck area. A three-dimensional, analytical model based on the sub-structuring approach is developed to characterize the complex structure-acoustic coupling between the DE membrane and its surrounding acoustic media. We show that such resonator provides sound attenuation in the medium frequency range mainly by means of sound reflection, as a result of the membrane vibration. The prediction accuracy of the proposed model is validated against experimental test. The pre-stretched DE membrane with fixed edges responds to applied voltage change with a varying inner stress and, by the same token, its natural frequency and vibrational response can be tuned to suit particular frequencies of interest. The peaks in the transmission loss (TL) curves can be shifted towards lower frequencies when the voltage applied to the DE membrane is increased. Through simulations on the effect of increasing the voltage level, the TL shifting mechanism and its possible tuning range are analyzed. This paves the way for applying such resonator device for adaptive-passive noise control.

  16. Characterization of ultraviolet light cured polydimethylsiloxane films for low-voltage, dielectric elastomer actuators (United States)

    Töpper, Tino; Wohlfender, Fabian; Weiss, Florian; Osmani, Bekim; Müller, Bert


    The reduction the operation voltage has been the key challenge to realize of dielectric elastomer actuators (DEA) for many years - especially for the application fields of robotics, lens systems, haptics and future medical implants. Contrary to the approach of manipulating the dielectric properties of the electrically activated polymer (EAP), we intend to realize low-voltage operation by reducing the polymer thickness to the range of a few hundred nanometers. A study recently published presents molecular beam deposition to reliably grow nanometer-thick polydimethylsiloxane (PDMS) films. The curing of PDMS is realized using ultraviolet (UV) radiation with wavelengths from 180 to 400 nm radicalizing the functional side and end groups. The understanding of the mechanical properties of sub-micrometer-thin PDMS films is crucial to optimize DEAs actuation efficiency. The elastic modulus of UV-cured spin-coated films is measured by nano-indentation using an atomic force microscope (AFM) according to the Hertzian contact mechanics model. These investigations show a reduced elastic modulus with increased indentation depth. A model with a skin-like SiO2 surface with corresponding elastic modulus of (2.29 +/- 0.31) MPa and a bulk modulus of cross-linked PDMS with corresponding elastic modulus of (87 +/- 7) kPa is proposed. The surface morphology is observed with AFM and 3D laser microscopy. Wrinkled surface microstructures on UV-cured PDMS films occur for film thicknesses above (510 +/- 30) nm with an UV-irradiation density of 7.2 10-4 J cm-2 nm-1 at a wavelength of 190 nm.

  17. Study on the Mathematical Model of Dielectric Recovery Characteristics in High Voltage SF6 Circuit Breaker (United States)

    Lin, Xin; Wang, Feiming; Xu, Jianyuan; Xia, Yalong; Liu, Weidong


    According to the stream theory, this paper proposes a mathematical model of the dielectric recovery characteristic based on the two-temperature ionization equilibrium equation. Taking the dynamic variation of charged particle's ionization and attachment into account, this model can be used in collaboration with the Coulomb collision model, which gives the relationship of the heavy particle temperature and electron temperature to calculate the electron density and temperature under different pressure and electric field conditions, so as to deliver the breakdown electric field strength under different pressure conditions. Meanwhile an experiment loop of the circuit breaker has been built to measure the breakdown voltage. It is shown that calculated results are in conformity with experiment results on the whole while results based on the stream criterion are larger than experiment results. This indicates that the mathematical model proposed here is more accurate for calculating the dielectric recovery characteristic, it is derived from the stream model with some improvement and refinement and has great significance for increasing the simulation accuracy of circuit breaker's interruption characteristic. supported by Science and Technology Project of State Grid Corporation of China (No. GY17201200063), National Natural Science Foundation of China (No. 51277123), Basic Research Project of Liaoning Key Laboratory of Education Department (LZ2015055)

  18. Electronics drivers for high voltage dielectric electro active polymer (DEAP) applications (United States)

    Zhang, Zhe; Andersen, Michael A. E.


    Dielectric electro active polymer (DEAP) can be used in actuation, sensing and energy harvesting applications, but driving the DEAP based actuators and generators has three main challenges from a power electronics standpoint, i.e. high voltage (around 2.5 kV), nonlinearity, and capacitive behavior. In this paper, electronics divers for heating valves, loud speakers, incremental motors, and energy harvesting are reviewed, studied and developed in accordance with their corresponding specifications. Due to the simplicity and low power capacity (below 10W), the reversible Fly-back converters with both magnetic and piezoelectric transformers are employed for the heating valve and incremental motor application, where only ON/OFF regulation is adopted for energy saving; as for DEAP based energy harvesting, the noisolated Buck/Boost converter is used, due to the system high power capacity (above 100W), but the voltage balancing across the series-connected high voltage IGBTs is a critical issue and accordingly a novel gate driver circuitry is proposed and equipped; due to the requirements of the audio products, such as low distortion and noise, the multi-level Buck converter based Class-D amplifier, because of its high control linearity, is implemented for the loud speaker applications. A synthesis among those converter topologies and control techniques is given; therefore, for those DEAP based applications, their diversity and similarity of electronics drivers, as well as the key technologies employed are analyzed. Therefore a whole picture of how to choose the proper topologies can be revealed. Finally, the design guidelines in order to achieve high efficiency and reliability are discussed.

  19. Electronics drivers for high voltage dielectric electro active polymer (DEAP) applications

    DEFF Research Database (Denmark)

    Zhang, Zhe; Andersen, Michael A. E.


    magnetic and piezoelectric transformers are employed for the heating valve and incremental motor application, where only ON/OFF regulation is adopted fo r energy saving; as for DEAP based energy harvesting, the no - isolated Buck/Boost converter is used, due to the system high power capacity (above 100W......), but the voltage balancing across the series - connected high voltage IGBTs is a critical issue and accordi ngly a novel gate driver circuitry is proposed and equipped; due to the requirements of the audio products, such as low distortion and noise, the multi - level Buck converter based Class - D amplifier....... In this paper, electronics divers for heating valves, loud speakers, incremental motors, and energy harvesting are reviewed, studied and developed in accordance with their corresponding specifications. Due to the simplicity and low power capacity (below 10W), the reversible Fly - back converters with both...

  20. Low-voltage flexible organic electronics based on high-performance sol-gel titanium dioxide dielectric. (United States)

    Sung, Sujin; Park, Sungjun; Lee, Won-June; Son, Jongho; Kim, Chang-Hyun; Kim, Yoonhee; Noh, Do Young; Yoon, Myung-Han


    In this letter, we report that high-performance insulating films can be generated by judicious control over the microstructure of sol-gel-processed titanium dioxide (TiO2) films, typically known as wide-bandgap semiconductors. The resultant device made of 23 nm-thick TiO2 dielectric layer exhibits a low leakage current density of ∼1 × 10(-7) A cm(-2) at 2 V and a large areal capacitance of 560 nF cm(-2) with the corresponding dielectric constant of 27. Finally, low-voltage flexible organic thin-film transistors were successfully demonstrated by incorporating this versatile solution-processed oxide dielectric material into pentacene transistors on polyimide substrates.

  1. A compact 300 kV solid-state high-voltage nanosecond generator for dielectric wall accelerator (United States)

    Shen, Yi; Wang, Wei; Liu, Yi; Xia, Liansheng; Zhang, Huang; Pan, Haifeng; Zhu, Jun; Shi, Jinshui; Zhang, Linwen; Deng, Jianjun


    Compact solid-state system is the main development trend in pulsed power technologies. A compact solid-state high-voltage nanosecond pulse generator with output voltage of 300 kV amplitude, 10 ns duration (FWHM), and 3 ns rise-time was designed for a dielectric wall accelerator. The generator is stacked by 15 planar-plate Blumlein pulse forming lines (PFL). Each Blumlein PFL consists of two solid-state planar transmission lines, a GaAs photoconductive semiconductor switch, and a laser diode trigger. The key components of the generator and the experimental results are reported in this paper.

  2. Controllable Threshold Voltage in Organic Complementary Logic Circuits with an Electron-Trapping Polymer and Photoactive Gate Dielectric Layer. (United States)

    Dao, Toan Thanh; Sakai, Heisuke; Nguyen, Hai Thanh; Ohkubo, Kei; Fukuzumi, Shunichi; Murata, Hideyuki


    We present controllable and reliable complementary organic transistor circuits on a PET substrate using a photoactive dielectric layer of 6-[4'-(N,N-diphenylamino)phenyl]-3-ethoxycarbonylcoumarin (DPA-CM) doped into poly(methyl methacrylate) (PMMA) and an electron-trapping layer of poly(perfluoroalkenyl vinyl ether) (Cytop). Cu was used for a source/drain electrode in both the p-channel and n-channel transistors. The threshold voltage of the transistors and the inverting voltage of the circuits were reversibly controlled over a wide range under a program voltage of less than 10 V and under UV light irradiation. At a program voltage of -2 V, the inverting voltage of the circuits was tuned to be at nearly half of the supply voltage of the circuit. Consequently, an excellent balance between the high and low noise margins (NM) was produced (64% of NMH and 68% of NML), resulting in maximum noise immunity. Furthermore, the programmed circuits showed high stability, such as a retention time of over 10(5) s for the inverter switching voltage. Our findings bring about a flexible, simple way to obtain robust, high-performance organic circuits using a controllable complementary transistor inverter.

  3. Solution-processed high-k magnesium oxide dielectrics for low-voltage oxide thin-film transistors (United States)

    Jiang, Guixia; Liu, Ao; Liu, Guoxia; Zhu, Chundan; Meng, You; Shin, Byoungchul; Fortunato, Elvira; Martins, Rodrigo; Shan, Fukai


    Solution-processed metal-oxide thin films with high dielectric constants (k) have been extensively studied for low-cost and high-performance thin-film transistors (TFTs). In this report, MgO dielectric films were fabricated using the spin-coating method. The MgO dielectric films annealed at various temperatures (300, 400, 500, and 600 °C) were characterized by using thermogravimetric analysis, optical spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and atomic-force microscopy. The electrical measurements indicate that the insulating properties of MgO thin films are improved with an increase in annealing temperature. In order to clarify the potential application of MgO thin films as gate dielectrics in TFTs, solution-derived In2O3 channel layers were separately fabricated on various MgO dielectric layers. The optimized In2O3/MgO TFT exhibited an electron mobility of 5.48 cm2/V s, an on/off current ratio of 107, and a subthreshold swing of 0.33 V/dec at a low operation voltage of 6 V. This work represents a great step toward the development of portable and low-power consumption electronics.

  4. Dielectric Electro Active Polymer Incremental Actuator Driven by Multiple High-Voltage Bi-directional DC-DC Converters

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.


    This paper presents driving circuit for a recently invented dielectric electro active polymer (DEAP) incremental actuator. The basic operation of such an actuator is bioinspired from the movement of an inchworm. The actuator consists of three electrically isolated, and mechanically connected....... The experimental results and efficiency measurements are shown....

  5. A Design of High—precision High—Voltage Fiber—Optic Analog Signal Isolation Converter

    Institute of Scientific and Technical Information of China (English)

    李建伟; 许留伟; 等


    This paper introduces a design of high-precision high-voltage fiber-optic analog signal isolation converter based on the technology of Voltage-to-Frequency(V/F) and Frequency-to-Voltage(F/V) conversion.It describes the principle,system configuration and hardware desin.

  6. First-principles study on dielectric function of isolated and bundled carbon nanotubes (United States)

    Yang, J. Y.; Liu, L. H.; Tan, J. Y.


    The dielectric function fundamentally determines the thermal radiative properties of nanomaterials. In this work, the first-principles method is applied to investigate the finite temperature dielectric function of isolated and bundled single-walled carbon nanotubes in the visible-ultraviolet spectral range without empirical models. The effects of diameter, intertube interactions and temperature on dielectric functions are discussed. The calculated extraordinary dielectric functions of four isolated (5,5), (6,6), (7,7) and (8,8) armchair nanotubes with different diameters are compared to study the diameter effect. It shows that the locations of absorption peaks of dielectric functions consistently shift to lower energy with increasing diameter. To analyze the influence of non-local intertube interactions, the dielectric functions of bundled (6,6) armchair nanotubes with varying intertube distance are calculated within the van der Waals theory. As nanotubes bundle together, the intertube interactions become strong and the absorption peaks enhance. The temperature effect is included into computing dielectric function of isolated (5,0) zigzag nanotubes via first-principles molecular dynamics method. It observes that the dominant absorption peak shifts to lower energy as temperature increases from 0 to 600 K. To interpret the temperature influence, the temperature perturbed density of states is presented.

  7. The formation of diffuse discharge by short-front nanosecond voltage pulses and the modification of dielectrics in this discharge (United States)

    Orlovskii, V. M.; Panarin, V. A.; Shulepov, M. A.


    The dynamics of diffuse discharge formation under the action of nanosecond voltage pulses with short fronts (below 1 ns) in the absence of a source of additional preionization and the influence of a dielectric film on this process have been studied. It is established that the diffuse discharge is induced by the avalanche multiplication of charge initiated by high-energy electrons and then maintained due to secondary breakdowns propagating via ionized gas channels. If a dielectric film (polyethylene, Lavsan, etc.) is placed on the anode, then multiply repeated discharge will lead to surface and bulk modification of the film material. Discharge-treated polyethylene film exhibits a change in the optical absorption spectrum in the near-IR range.

  8. Threshold-Voltage Shifts in Organic Transistors Due to Self-Assembled Monolayers at the Dielectric: Evidence for Electronic Coupling and Dipolar Effects. (United States)

    Aghamohammadi, Mahdieh; Rödel, Reinhold; Zschieschang, Ute; Ocal, Carmen; Boschker, Hans; Weitz, R Thomas; Barrena, Esther; Klauk, Hagen


    The mechanisms behind the threshold-voltage shift in organic transistors due to functionalizing of the gate dielectric with self-assembled monolayers (SAMs) are still under debate. We address the mechanisms by which SAMs determine the threshold voltage, by analyzing whether the threshold voltage depends on the gate-dielectric capacitance. We have investigated transistors based on five oxide thicknesses and two SAMs with rather diverse chemical properties, using the benchmark organic semiconductor dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene. Unlike several previous studies, we have found that the dependence of the threshold voltage on the gate-dielectric capacitance is completely different for the two SAMs. In transistors with an alkyl SAM, the threshold voltage does not depend on the gate-dielectric capacitance and is determined mainly by the dipolar character of the SAM, whereas in transistors with a fluoroalkyl SAM the threshold voltages exhibit a linear dependence on the inverse of the gate-dielectric capacitance. Kelvin probe force microscopy measurements indicate this behavior is attributed to an electronic coupling between the fluoroalkyl SAM and the organic semiconductor.

  9. Analysis of Dielectric Electro Active Polymer Actuator and its High Voltage Driving Circuits

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Huang, Lina; Zhang, Zhe


    Actuators based on dielectric elastomers have promising applications in artificial muscles, space robotics, mechatronics, micro-air vehicles, pneumatic and electric automation technology, heating valves, loud speakers, tissue engineering, surgical tools, wind turbine flaps, toys, rotary motors...

  10. Amorphous Strontium Titanate Film as Gate Dielectric for Higher Performance and Low Voltage Operation of Transparent and Flexible Organic Field Effect Transistor. (United States)

    Yadav, Sarita; Ghosh, Subhasis


    We report that the pervoskite material, strontium titanate (STO) can be used as a gate dielectric layer of flexible and low voltage organic field effect transistor (OFET). The crystallinity, dielectric constant, and surface morphology of STO films can be controlled by the engineering of the growth condition. Under optimized growth condition, amorphous films of STO show a much better gate dielectric compared to other gate dielectrics used to date, with very small leakage current density for flexible and low voltage (transistors with amorphous STO gate dielectric show high mobility of 2 cm(2)/(V s), on/off ratio of 10(6), subthreshold swing of 0.3 V/dec and low interface trap density. Similarly excellent performance has been obtained in copper phthalocyanine (CuPc) based OFETs with on/off ratio ∼10(5) and carrier mobility ∼5.9 × 10(-2) cm(2)/(V s). Moreover, the operating voltage (∼5 V) has been reduced by more than one order of magnitude. It has been demonstrated that the low processing temperature of amorphous STO makes it the most suitable gate dielectric for flexible and transparent organic devices to operate under low voltage.

  11. Flexible low-voltage polymer thin-film transistors using supercritical CO2-deposited ZrO2 dielectrics. (United States)

    Wei, Qingshuo; You, Eunyoung; Hendricks, Nicholas R; Briseno, Alejandro L; Watkins, James J


    The fabrication of low-voltage flexible organic thin film transistors using zirconia (ZrO(2)) dielectric layers prepared via supercritical fluid deposition was studied. Continuous, single-phase films of approximately 30 nm thick ZrO(2) were grown on polyimide (PI)/aluminum (Al) substrates at 250 °C via hydrolysis of tetrakis(2,2,6,6-tetramethyl-3,5-heptane-dionato) zirconium in supercritical carbon dioxide. This dielectric layer showed a high areal capacitance of 317 nF cm(-2) at 1 kHz and a low leakage current of 1.8 × 10(-6) A cm(-2) at an applied voltage of -3 V. By using poly(3-hexylthiophene) (P3HT) as a semiconductor, we have fabricated flexible thin film transistors operating at V(DS) = -0.5 V and V(G) in a range from 0.5 V to -4 V, with on/off ratios on the order of 1 × 10(3) and mobility values higher than 0.1 cm(2)/(V s).

  12. Multifunctional shape memory electrodes for dielectric elastomer actuators enabling high holding force and low-voltage multisegment addressing (United States)

    McCoul, David; Rosset, Samuel; Besse, Nadine; Shea, Herbert


    Dielectric elastomer actuators (DEAs) are an attractive form of electromechanical transducer, possessing high energy densities, an efficient design, mechanical flexibility, high speed, and noiseless operation. They have been incorporated into a variety of elegant devices, such as microfluidic devices, tunable optics, haptic displays, and minimum-energy grippers. Dielectric elastomer minimum energy structures (DEMESs) take advantage of the prestretch of the DEA to bend a non-stretchable but flexible component to perform mechanical work. The gripper is perhaps the most intuitive type of DEMES, capable of grasping objects but with only small to moderate forces. We present a novel configuration of a DEA using electrodes made of a conductive shape-memory polymer (SMP), incorporated into the design of a gripper. The SMP electrodes allow the DEA to be rigid in the cold state, offering greater holding force than a conventional gripper. Joule heating applied to the SMP electrodes softens them, allowing for electrostatic actuation. Cooling then locks in the actuated position without the need for continued power to be supplied. Additionally, the Joule heating voltage is at least one order of magnitude less than electrostatic actuation voltages, allowing for addressing of multiple actuator elements using commercially available transistors. The shape memory gripper incorporates this addressing into its design, enabling the three segments of each finger to be controlled independently.

  13. Dielectric properties of isolated clusters beam deflection studies

    CERN Document Server

    Heiles, Sven


    A broad range of state-of-the-art methods to determine properties of clusters are presented. The experimental setup and underlying physical concepts of these experiments are described. Furthermore, existing theoretical models to explain the experimental observations are introduced and the possibility to deduce structural information from measurements of dielectric properties is discussed. Additional case studies are presented in the book to emphasize the possibilities but also drawbacks of the methods.

  14. Electronics drivers for high voltage dielectric electro active polymer (DEAP) applications

    DEFF Research Database (Denmark)

    Zhang, Zhe; Andersen, Michael A. E.


    ), but the voltage balancing across the series - connected high voltage IGBTs is a critical issue and accordi ngly a novel gate driver circuitry is proposed and equipped; due to the requirements of the audio products, such as low distortion and noise, the multi - level Buck converter based Class - D amplifier...

  15. Cascaded transformerless DC-DC voltage amplifier with optically isolated switching devices (United States)

    Sridharan, Govind (Inventor)


    A very high voltage amplifier is provided in which plural cascaded banks of capacitors are switched by optically isolated control switches so as to be charged in parallel from the preceding stage or capacitor bank and to discharge in series to the succeeding stage or capacitor bank in alternating control cycles. The optically isolated control switches are controlled by a logic controller whose power supply is virtually immune to interference from the very high voltage output of the amplifier by the optical isolation provided by the switches, so that a very high voltage amplification ratio may be attained using many capacitor banks in cascade.

  16. A Xenon dielectric barrier discharge lamp (172nm) with a fast-pulse voltage driver: Influence of the voltage waveform on plasma kinetic issues and light output. (United States)

    Carman, Robert; Ward, Barry; Mildren, Richard; Kane, Deborah


    An important class of vacuum-ultraviolet (VUV) excimer lamps based on high pressure rare-gas and rare-gas halogen mixtures utilize the dielectric barrier discharge (DBD) to generate a transient, non-equilibrium plasma that yields high electrical to VUV conversion efficiency. Recent interest has focussed on the use of pulsed voltage excitation techniques (rather than conventional AC sinusoidal waveforms) to alter the physical appearance of the DBD "micro-discharges" from filamentary (AC) to semi-diffuse, conical or homogeneous (pulsed), whilst at the same time dramatically improving the lamp performance and VUV efficiency^1,2. We report results from a combined experimental/computer modelling study of a short-pulse excited co-axial DBD Xe lamp to investigate the influence of the pulsed voltage waveform on the discharge structure, lamp performance, VUV output, and electrical efficiency. The underlying plasma kinetics issues relating to lamp performance, including parasitic collisional processes that act to quench key xenon species population densities, are examined in detail. ^1 Vollkommer F and Hitzschke, US patent 5604410 (1997) ^2 R.P.Mildren and R.J.Carman, J.Phys.D, 34, L1-L6 (2001)

  17. Voltage tunable dielectric properties of oxides at nanoscale: TiO2 and CeO2 as model systems (United States)

    Prakash, T.; Tamil Selvan, A.; Suraiya Begum, S. N.


    Carrier transport through electrically active grain boundaries has been studied under biased condition using Solartron 1260 impedance/gain phase analyzer with an applied AC potential of 250 mV in the frequency range 1 Hz-1 MHz for nanocrystalline TiO2 and CeO2 as the model systems. Prior to the measurement both the materials were converted into cylindrical pellets with (8 mm diameter and 1 mm thick) by applying uni-axial pressure of 4 ton using a hydraulic press, then sintered at 300, 450 and 600 °C for 30 min for TiO2 sample and for the case of CeO2 it was done at 300, 600 and 900 °C for 30 min. Further, they were characterized using powder X-ray diffractometer (XRD) and transmission electron microscopy (TEM) to know the crystal structure, average crystallite size and morphology. The impedance measurements were performed at room temperature under applied DC bias voltages from 0 to 3 V in the periodic increment of 0.2 V. The observed applied bias voltage effect on dielectric constant of both the systems was analyzed with 'grain boundary double Schottky potential barrier height model' for different grain sizes. The percentage of voltage tunable dielectric constant (T%) as a function of frequency was estimated for all the grain sizes and it was found to be increase with reduction of grain size. Our experimental findings reveal the possibilities of utilizing these nanocrystals as a potential active material for phased array antenna since both the samples exhibits T% = 85% at 100 Hz frequency.

  18. High Radiation Tolerant Ceramic Voltage Isolator (Non-optical Gate Driver) Project (United States)

    National Aeronautics and Space Administration — The goal of the Phase I effort is to design, develop and demonstrate a novel solid-state ceramic-based voltage isolator and demonstrate its potential to provide a...

  19. Novel design of high voltage pulse source for efficient dielectric barrier discharge generation by using silicon diodes for alternating current (United States)

    Truong, Hoa Thi; Hayashi, Misaki; Uesugi, Yoshihiko; Tanaka, Yasunori; Ishijima, Tatsuo


    This work focuses on design, construction, and optimization of configuration of a novel high voltage pulse power source for large-scale dielectric barrier discharge (DBD) generation. The pulses were generated by using the high-speed switching characteristic of an inexpensive device called silicon diodes for alternating current and the self-terminated characteristic of DBD. The operation started to be powered by a primary DC low voltage power supply flexibly equipped with a commercial DC power supply, or a battery, or DC output of an independent photovoltaic system without transformer employment. This flexible connection to different types of primary power supply could provide a promising solution for the application of DBD, especially in the area without power grid connection. The simple modular structure, non-control requirement, transformer elimination, and a minimum number of levels in voltage conversion could lead to a reduction in size, weight, simple maintenance, low cost of installation, and high scalability of a DBD generator. The performance of this pulse source has been validated by a load of resistor. A good agreement between theoretically estimated and experimentally measured responses has been achieved. The pulse source has also been successfully applied for an efficient DBD plasma generation.

  20. Analysis of high voltage dielectric insulation materials of XLPE by THz-TDS system (United States)

    Shi, Wei; Yan, Zhijin; Yang, Lei; Dai, Yang; Zhang, Like; Bian, Kangkang; Hou, Lei


    In this paper, cross-linked polyethylene (XLPE) was analyzed by THz time domain spectroscopy (TDS) system at room temperature. By recording time domain signal of terahertz radiation field, frequency spectrum can be obtained by Fourier transform. Then the refractive index and dielectric constant in THz band are calculated. This proves that the THz-TDS system has a potential application for detecting the aging characteristic of XLPE.

  1. Experimental investigation of dielectric barrier discharge plasma actuators driven by repetitive high-voltage nanosecond pulses with dc or low frequency sinusoidal bias (United States)

    Opaits, Dmitry F.; Likhanskii, Alexandre V.; Neretti, Gabriele; Zaidi, Sohail; Shneider, Mikhail N.; Miles, Richard B.; Macheret, Sergey O.


    Experimental studies were conducted of a flow induced in an initially quiescent room air by a single asymmetric dielectric barrier discharge driven by voltage waveforms consisting of repetitive nanosecond high-voltage pulses superimposed on dc or alternating sinusoidal or square-wave bias voltage. To characterize the pulses and to optimize their matching to the plasma, a numerical code for short pulse calculations with an arbitrary impedance load was developed. A new approach for nonintrusive diagnostics of plasma actuator induced flows in quiescent gas was proposed, consisting of three elements coupled together: the schlieren technique, burst mode of plasma actuator operation, and two-dimensional numerical fluid modeling. The force and heating rate calculated by a plasma model was used as an input to two-dimensional viscous flow solver to predict the time-dependent dielectric barrier discharge induced flow field. This approach allowed us to restore the entire two-dimensional unsteady plasma induced flow pattern as well as characteristics of the plasma induced force. Both the experiments and computations showed the same vortex flow structures induced by the actuator. Parametric studies of the vortices at different bias voltages, pulse polarities, peak pulse voltages, and pulse repetition rates were conducted experimentally. The significance of charge buildup on the dielectric surface was demonstrated. The charge buildup decreases the effective electric field in the plasma and reduces the plasma actuator performance. The accumulated surface charge can be removed by switching the bias polarity, which leads to a newly proposed voltage waveform consisting of high-voltage nanosecond repetitive pulses superimposed on a high-voltage low frequency sinusoidal voltage. Advantages of the new voltage waveform were demonstrated experimentally.

  2. Switch-mode High Voltage Drivers for Dielectric Electro Active Polymer (DEAP) Incremental Actuators

    DEFF Research Database (Denmark)

    Thummala, Prasanth

    , a new bidirectional flyback converter topology with multiple series connected outputs is proposed. A theoretical comparison showed that the proposed converter could improve the overall energy efficiency, lower the cost and reduce the volume of high voltage driver. Key words: high voltage, switch...... operation, and low power consumption. DEAP actuators require very high voltage (2-2.5 kV) to fully elongate them. In general, the elongation or stroke length of a DEAP actuator is of the order of mm. DEAP actuators can be configured to provide incremental motion, thus overcoming the inherent size......-to-stroke implications of conventional linear actuators, where the stroke is limited by their size. In incremental mode, DEAP actuators are several orders of magnitude shorter in their length compared to the stroke/elongation they provide. The dissertation presents design, control and implementation of switch-mode high...

  3. Solution-deposited sodium beta-alumina gate dielectrics for low-voltage and transparent field-effect transistors. (United States)

    Pal, Bhola N; Dhar, Bal Mukund; See, Kevin C; Katz, Howard E


    Sodium beta-alumina (SBA) has high two-dimensional conductivity, owing to mobile sodium ions in lattice planes, between which are insulating AlO(x) layers. SBA can provide high capacitance perpendicular to the planes, while causing negligible leakage current owing to the lack of electron carriers and limited mobility of sodium ions through the aluminium oxide layers. Here, we describe sol-gel-beta-alumina films as transistor gate dielectrics with solution-deposited zinc-oxide-based semiconductors and indium tin oxide (ITO) gate electrodes. The transistors operate in air with a few volts input. The highest electron mobility, 28.0 cm2 V(-1) s(-1), was from zinc tin oxide (ZTO), with an on/off ratio of 2 x 10(4). ZTO over a lower-temperature, amorphous dielectric, had a mobility of 10 cm2 V(-1) s(-1). We also used silicon wafer and flexible polyimide-aluminium foil substrates for solution-processed n-type oxide and organic transistors. Using poly(3,4-ethylenedioxythiophene) poly(styrenesulphonate) conducting polymer electrodes, we prepared an all-solution-processed, low-voltage transparent oxide transistor on an ITO glass substrate.

  4. A High-Voltage Class D Audio Amplifier for Dielectric Elastomer Transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.


    Dielectric Elastomer (DE) transducers have emerged as a very interesting alternative to the traditional electrodynamic transducer. Lightweight, small size and high maneuverability are some of the key features of the DE transducer. An amplifier for the DE transducer suitable for audio applications...... is proposed and analyzed. The amplifier addresses the issue of a high impedance load, ensuring a linear response over the midrange region of the audio bandwidth (100 Hz – 3.5 kHz). THD+N below 0.1% are reported for the ± 300 V prototype amplifier producing a maximum of 125 Var at a peak efficiency of 95 %....

  5. A high voltage gain quasi Z-source isolated DC/DC converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Blaabjerg, Frede; Loh, Poh Chiang


    A compact quasi-Z-source DC/DC converter is presented with high voltage gain, isolated output, and improved efficiency. The improvements in size and performance were achieved by using a square wave inverter with only two output switches driving an isolating transformer in push-pull mode, followed...

  6. High-voltage boost quasi-Z-source isolated DC/DC converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Blaabjerg, Frede; Loh, Poh Chiang


    A high-voltage gain two-switch quasi-Z-source isolated DC/DC converter has been presented in this study. It consists of a quasi-Z-source network at its input, a push-pull square-wave inverter at its middle, and a voltage-doubler rectifier at its output. When coordinated appropriately, the new...... converter uses less switches, a smaller common duty cycle and less turns for the transformer when compared with existing topologies. Its size and weight are therefore smaller, whereas its efficiency is higher. It is therefore well-suited for applications, where a wide range of voltage gain is required like...

  7. Low-operating-voltage polymer thin-film transistors based on poly(3-hexylthiophene) with hafnium oxide as the gate dielectric


    Liu, YR; Deng, LF; Yao, RH; Lai, PT


    The effects of hafnium oxide $(hbox{HfO}-{2})$ gate dielectric annealing treatment in oxygen $(hbox{O}-{2})$ and ammonia $(hbox{NH}-{3})$ ambient on the electrical performance of polymer thin-film transistors (PTFTs) based on poly(3-hexylthiophene) are investigated. The PTFTs with $hbox{HfO}-{2}$ gate dielectric and also octadecyltrichlorosilane surface modification, prepared by spin-coating process, exhibit good performance, such as a small threshold voltage of $-$0.5 V and an operating volt...

  8. Dielectric barrier discharges with steep voltage rise: mapping of atomic nitrogen in single filaments measured by laser-induced fluorescence spectroscopy (United States)

    Lukas, C.; Spaan, M.; Schulz-von der Gathen, V.; Thomson, M.; Wegst, R.; Döbele, H. F.; Neiger, M.


    Space and time resolved relative atomic density distributions of nitrogen have been measured for the first time at a single filament within a dielectric barrier discharge (DBD) reactor with submillimetre radial dimensions. Two-photon-Absorption Laser-Induced Fluorescence (TALIF) spectroscopy of atomic nitrogen using radiation at λ = 206.7 nm is applied to a DBD with fast rising voltage amplitudes. The decay time of the atomic nitrogen density depends strongly on the position within the discharge and the distance from the dielectric where the lifetime is maximum. Admixed oxygen leads to an increase of the N density decay by an order of magnitude even at small fractions.

  9. Electronics drivers for high voltage dielectric electro active polymer (DEAP) applications

    DEFF Research Database (Denmark)

    Zhang, Zhe; Andersen, Michael A. E.


    magnetic and piezoelectric transformers are employed for the heating valve and incremental motor application, where only ON/OFF regulation is adopted fo r energy saving; as for DEAP based energy harvesting, the no - isolated Buck/Boost converter is used, due to the system high power capacity (above 100W...

  10. Electrospraying and ultraviolet light curing of nanometer-thin polydimethylsiloxane membranes for low-voltage dielectric elastomer transducers (United States)

    Osmani, Bekim; Töpper, Tino; Siketanc, Matej; Kovacs, Gabor M.; Müller, Bert


    Dielectric elastomer transducers (DETs) have attracted interest as actuators, sensors, and even as self-sensing actuators for applications in medicine, soft robotics, and microfluidics. To reach strains of more than 10 %, they currently require operating voltages of several hundred volts. In medical applications for artificial muscles, however, their operation is limited to a very few tens of volts, which implies high permittivity materials and thin-film structures. Such micro- or nanostructures can be prepared using electro-spraying, a cost-effective technique that allows upscaling using multiple nozzles for the fabrication of silicone films down to nanometer thickness. Deposition rates of several micrometers per hour have already been reached. It has been recently demonstrated that such membranes can be fabricated by electro-spraying and subsequent ultraviolet light irradiation. Herein, we introduce a relatively fast deposition of a dimethyl silicone copolymer fluid that contains mercaptopropyl side chains in addition to the methyl groups. Its elastic modulus was tuned with the irradiation dose of the 200 W Hg-Xe lamp. We also investigated the formation of elastomer films, using polymer concentrations in ethyl acetate of 1, 2, 5 and 10 vol%. After curing, the surface roughness was measured by means of atomic force microscopy. This instrument also enabled us to determine the average elastic modulus out of, for example, 400 nanoindentation measurements, using a spherical tip with a radius of 500 nm. The elastomer films were cured for a period of less than one minute, a speed that makes it feasible to combine electro-spraying and in situ curing in a single process step for fabricating low-voltage, multilayer DETs.

  11. On the influence of high voltage slope steepness on breakdown and development of pulsed dielectric barrier discharges (United States)

    Höft, H.; Becker, M. M.; Loffhagen, D.; Kettlitz, M.


    The influence of the steepness of the applied high voltage (HV) waveform on the characteristics of pulsed dielectric barrier discharges (DBDs) is investigated using a single-filament arrangement with 1 mm gap in 0.1 vol% O2 in N2 at atmospheric pressure. The slope steepness was varied between 75 V ns-1 and 200 V ns-1. The discharge development was recorded with a combined iCCD and streak camera system accompanied by electrical measurements. The analysis was supported by time-dependent, spatially one-dimensional fluid model calculations. A steeper HV slope leads to a higher transferred charge and electrical energy per cycle. The DBD emission structure in the gap features a shorter ‘dark space’ in front of the cathode for steeper HV pulses. The starting velocity of the positive streamer-like propagation at the rising slope of the HV pulses increases with increasing slope steepness, but without influencing the maximal velocity in front of the cathode. At the falling slope, however, smaller propagation velocities for steeper pulses were measured. The modelling results and the measurements of the emission during the pre-phase suggest that the elevated pre-ionisation and higher electrical energy for steeper HV slopes is responsible for most of the observed effects.

  12. Modeling of the Partial Discharge Process in a Liquid Dielectric: Effect of Applied Voltage, Gap Distance, and Electrode Type

    Directory of Open Access Journals (Sweden)

    Tao Yuan


    Full Text Available The partial discharge (PD process in liquid dielectrics is influenced by several factors. Although the PD current contains the information representing the discharge process during the PD event, it is difficult to determine the detailed dynamics of what is happening in the bulk of the liquid. In this paper, a microscopic model describing the dynamics of the charge carriers is implemented. The model consists of drift-diffusion equations of electrons, positive and negative ions coupled with Poisson’s equation. The stochastic feature of PD events is included in the equation. First the model is validated through comparison between the calculated PD current and experimental data. Then experiments are conducted to study the effects of the amplitude of the applied voltage, gap distance and electrode type on the PD process. The PD currents under each condition are recorded. Simulations based on the model have been conducted to analyze the dynamics of the PD events under each condition, and thus explain the mechanism of how these factors influence the PD events. The space charge generated in the PD process is revealed as the main reason affecting the microscopic process of the PD events.

  13. A threshold voltage model of short-channel fully-depleted recessed-source/drain (Re-S/D) SOI MOSFETs with high- dielectric

    Institute of Scientific and Technical Information of China (English)

    Gopi Krishna Saramekala; Sarvesh Dubey; Pramod Kumar Tiwari


    In this paper, a surface potential based threshold voltage model of fully-depleted (FD) recessed-source/drain (Re-S/D) silicon-on-insulator (SOI) metal-oxide semiconductor field-effect transistor (MOSFET) is presented while considering the effects of high-k gate-dielectric material induced fringing-field. The two-dimensional (2D) Poisson’s equation is solved in a channel region in order to obtain the surface potential under the assumption of the parabolic potential profile in the trans-verse direction of the channel with appropriate boundary conditions. The accuracy of the model is verified by comparing the model’s results with the 2D simulation results from ATLAS over a wide range of channel lengths and other parameters, including the dielectric constant of gate-dielectric material.

  14. Examination of flatband and threshold voltage tuning of HfO2/TiN field effect transistors by dielectric cap layers (United States)

    Guha, S.; Paruchuri, V. K.; Copel, M.; Narayanan, V.; Wang, Y. Y.; Batson, P. E.; Bojarczuk, N. A.; Linder, B.; Doris, B.


    The authors have examined the role of sub nanometer La2O3 and LaN cap layers interposed in Si /HfO2/TiN high-k gate dielectric stacks in tuning the flatband and threshold voltages of capacitors and transistors. High performance, band edge n metal oxide field effect transistors with channel lengths down to 60nm may be fabricated without significant compromise in mobility, electrical thickness, and threshold voltage. They have carried out a microstructural evaluation of these stacks and correlated these results with the electrical behavior of the devices.

  15. A High Voltage-lift Efficient Isolated Full Bridge DC-DC Converter

    Directory of Open Access Journals (Sweden)

    A. Gopi


    Full Text Available The aim of this study is to propose a high voltage lift isolated full bridge dc-dc converter. The proposed converter consists of an isolation transformer a low turn ratio to obtain high step up voltage gain. The secondary of the transformer connected with two boosting capacitors which connects parallel when power switches switch on period and discharged in series during the switch off period. In addition full bridge converter on primary side consists of clamping diode and capacitor, leakage energy is recycled there by improving conversion efficiency. The proposed circuits simulated using PSIM software form input voltage of 48V, an output of 410 V obtained. These results and operations experimented and validated by implementing in hardware model at 20/40 Vdc, 20 Watts.

  16. The low threshold voltage n-type silicon transistors based on a polymer/silica nanocomposite gate dielectric: The effect of annealing temperatures on their operation (United States)

    Hashemi, Adeleh; Bahari, Ali; Ghasemi, Shahram


    In this work, povidone/silica nanocomposite dielectric layers were deposited on the n-type Si (100) substrates for application in n-type silicon field-effect transistors (FET). Thermogravimetric analysis (TGA) indicated that strong chemical interactions between polymer and silica nanoparticles were created. In order to examine the effect of annealing temperatures on chemical interactions and nanostructure properties, annealing process was done at 423-513 K. Atomic force microscopy (AFM) images show the very smooth surfaces with very low surface roughness (0.038-0.088 nm). The Si2p and C1s core level photoemission spectra were deconvoluted to the chemical environments of Si and C atoms respectively. The obtained results of deconvoluted X-ray photoelectron spectroscopy (XPS) spectra revealed a high percentage of silanol hydrogen bonds in the sample which was not annealed. These bonds were inversed to stronger covalence bonds (siloxan bonds) at annealing temperature of 423 K. By further addition of temperature, siloxan bonds were shifted to lower binding energy of about 1 eV and their intensity were abated at annealing temperature of 513 K. The electrical characteristics were extracted from current-Voltage (I-V) and capacitance-voltage (C-V) measurements in metal-insulator-semiconductor (MIS) structure. The all n-type Si transistors showed very low threshold voltages (-0.24 to 1 V). The formation of the strongest cross-linking at nanostructure of dielectric film annealed at 423 K caused resulted in an un-trapped path for the transport of charge carriers yielding the lowest threshold voltage (0.08 V) and the highest electron mobility (45.01 cm2/V s) for its FET. By increasing the annealing temperature (473 and 513 K) on the nanocomposite dielectric films, the values of the average surface roughness, the capacitance and the FET threshold voltage increased and the value of FET electron field-effect mobility decreased.

  17. To a Method of Polarization-Depolarization Currents for Diagnosis of Dielectric Isolation (United States)

    Ambrozevich, S. A.; Sibatov, R. T.; Uchaikin, D. V.; Morozova, E. V.


    Fractional derivative formalism is proposed as the mathematical foundation of the polarization-depolarization current method for the diagnosis of dielectric isolation. Physical basis of the new approach is the observed deviation of the long-term relaxation from the Debye exponential law. We found that this behavior is consistent with the solution of the fractional differential equation: exponential behavior turns into the power dependence in the long-time asymptotics, and this part of the relaxation curve is more sensitive to the material state. The results of calculations for the polarization-depolarization currents in an oil-paper capacitor are in agreement with the specially performed experiments.

  18. Abnormal Growth Analysis of Dielectric Loss Factor in Capacitor Voltage Transformer%电容式电压互感器介损增长异常分析

    Institute of Scientific and Technical Information of China (English)

    陈润颖; 王周祥


    Dielectric loss grew abnormally in the prophylactic test of capacitor voltage transformer. Dielectric loss was reduced to 0.045% and electric capacity was increased by 4.42% when the test voltage of the device was increased from 10 kV to 81 kV. When test voltage was increased to 100 kV, dielectric loss and capacitance no longer changed. Six capacitors were found breakdown by the calculation and disassembling analysis. Results indicated that the vacuum degree of capacitors in the manufacturing process does not meet the requirements, which produced partial discharge, broken down the capacitance incompletely, and increased the resistance, resulted in abnormal growth of dielectric loss.%在电容式电压互感器预防性试验中,发现介损增长异常.对其设备提高试验电压,随着电压从10 kV升高至81 kV,介损下降到0.045%,电容量增大4.42%,当电压继续升高至100 kV,介损及电容量不再变化.通过计算及解体试验证实有6个电容击穿.分析结果表明:由于电容在制造过程中真空度未达到要求,发生局部放电,电容未完全击穿,电阻增大,导致介损增长异常.

  19. A Voltage Regulator for Parallel Operated Isolated Synchronous Generators Using Statcom

    Directory of Open Access Journals (Sweden)

    Sravanthi Gudipati,


    Full Text Available Reactive power (vars is required to maintain the voltage to deliver active power through transmission lines. Generator and other loads require reactive power to convert the flow of electrons into useful work. When there is not enough reactive power, the voltage sags down and it is not possible to push the power demanded by loads through the lines. Thus reactive power is injected using the compensating device STATCOM.The Paper deals on static synchronous compensator (STATCOM which is connected to the parallel operated isolated synchronous generators to drive a 3-phase load. These generators are driven by constant prime mover like diesel engine,bio-mass,gasoline,steam turbine etc.Three single phase IGBT based Voltage source converter (VSC along with 3-single phase transformers and self supported D.C bus is used as a voltage controller. The project deals with controlling a STATCOM using non-linear techniques that involves hysteresis current control and Park’s transformation. The voltage controller of parallel operated generators for feeding 3-phase loads driven by constant speed prime mover like Hydraulic turbine governor model helps in satisfactory operation under varying loads and in load balancing. If the line current is less than the expected, the compensating current generated by STATCOM is taken by loads.

  20. A tubular dielectric elastomer actuator: Fabrication, characterization and active vibration isolation

    DEFF Research Database (Denmark)

    Sarban, R.; Jones, R. W.; Mace, B. R.;


    This contribution reviews the fabrication, characterization and active vibration isolation performance of a core-free rolled tubular dielectric elastomer (DE) actuator, which has been designed and developed by Danfoss PolyPower A/S. PolyPower DE material, PolyPower (TM), is produced in thin sheets...... of 80 mu m thickness with corrugated metallic electrodes on both sides. Tubular actuators are manufactured by rolling the DE sheets in a cylindrical shape. The electromechanical characteristics of such actuators are modeled based on equilibrium pressure equation. The model is validated with experimental...... the dominant dynamic characteristics of the core-free tubular actuator. It has been observed that all actuators have similar dynamic characteristics in a frequency range up to 1 kHz. A tubular actuator is then used to provide active vibration isolation (AVI) of a 250 g mass subject to shaker generated 'ground...

  1. Multiple-Time-Scales Hierarchical Frequency Stability Control Strategy of Medium-Voltage Isolated Microgrid

    DEFF Research Database (Denmark)

    Zhao, Zhuoli; Yang, Ping; Guerrero, Josep M.


    In this paper, an islanded medium-voltage (MV) microgrid placed in Dongao Island is presented, which integrates renewable-energy-based distributed generations (DGs), energy storage system (ESS), and local loads. In an isolated microgrid without connection to the main grid to support the frequency...... of Zone B. Theoretical analysis, time-domain simulation and field test results under various conditions and scenarios in the Dongao Island microgrid are presented to prove the validity of the introduced control strategy....

  2. Clinical meaning of isolated increase of QRS voltages in hypertrophic cardiomyopathy versus athlete's heart. (United States)

    Calore, Chiara; Zorzi, Alessandro; Corrado, Domenico


    Recent consensus documents have provided modern criteria for interpretation of the athlete's ECG, which are based on a better definition of physiological versus abnormal ECG changes. The aim of these modern criteria is to lower the traditionally high number of false positives and to reduce unnecessary and expensive investigations, maintaining the sensitivity for identification of cardiac diseases at risk of sudden cardiac death during sports such as hypertrophic cardiomyopathy (HCM). This article reviews the published studies regarding the ECG changes associated with HCM ("pathologic hypertrophy") and athlete's heart ("physiologic hypertrophy"), with particular reference to the prevalence and clinical significance of the ECG pattern of isolated increase of QRS voltages. Taken together the results of the available studies show that ECG provides good accuracy for differentiating HCM from athlete's heart and allows to preserve the ECG power for detection of athletes with HCM. Patients with either completely normal ECGs or showing isolated QRS voltage criteria for LV hypertrophy have a less severe HCM phenotype, which is associated with a lower arrhythmic risk. These scientific data support the current recommendation that further cardiovascular tests including echocardiography are not systematically indicated in trained athletes showing an isolated increase of QRS voltages. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. An isolated bridgeless AC-DC PFC converter using a LC resonant voltage doubler rectifier (United States)

    Lee, Sin-woo; Do, Hyun-Lark


    This paper proposed an isolated bridgeless AC-DC power factor correction (PFC) converter using a LC resonant voltage doubler rectifier. The proposed converter is based on isolated conventional single-ended primary inductance converter (SEPIC) PFC converter. The conduction loss of rectification is reduced than a conventional one because the proposed converter is designed to eliminate a full-bridge rectifier at an input stage. Moreover, for zero-current switching (ZCS) operation and low voltage stresses of output diodes, the secondary of the proposed converter is designed as voltage doubler with a LC resonant tank. Additionally, an input-output electrical isolation is provided for safety standard. In conclusion, high power factor is achieved and efficiency is improved. The operational principles, steady-state analysis and design equations of the proposed converter are described in detail. Experimental results from a 60 W prototype at a constant switching frequency 100 kHz are presented to verify the performance of the proposed converter.

  4. SEMICONDUCTOR DEVICES Process optimization of a deep trench isolation structure for high voltage SOI devices (United States)

    Kuiying, Zhu; Qinsong, Qian; Jing, Zhu; Weifeng, Sun


    The process reasons for weak point formation of the deep trench on SOI wafers have been analyzed in detail. An optimized trench process is also proposed. It is found that there are two main reasons: one is over-etching laterally of the silicon on the surface of the buried oxide caused by a fringe effect; and the other is the slow growth rate of the isolation oxide in the concave silicon corner of the trench bottom. In order to improve the isolation performance of the deep trench, two feasible ways for optimizing the trench process are proposed. The improved process thickens the isolation oxide and rounds sharp silicon corners at their weak points, increasing the applied voltage by 15-20 V at the same leakage current. The proposed new trench isolation process has been verified in the foundry's 0.5-μm HV SOI technology.

  5. High voltage switches having one or more floating conductor layers

    Energy Technology Data Exchange (ETDEWEB)

    Werne, Roger W.; Sampayan, Stephen; Harris, John Richardson


    This patent document discloses high voltage switches that include one or more electrically floating conductor layers that are isolated from one another in the dielectric medium between the top and bottom switch electrodes. The presence of the one or more electrically floating conductor layers between the top and bottom switch electrodes allow the dielectric medium between the top and bottom switch electrodes to exhibit a higher breakdown voltage than the breakdown voltage when the one or more electrically floating conductor layers are not present between the top and bottom switch electrodes. This increased breakdown voltage in the presence of one or more electrically floating conductor layers in a dielectric medium enables the switch to supply a higher voltage for various high voltage circuits and electric systems.

  6. Transfer of Kv3.1 voltage sensor features to the isolated Ci-VSP voltage-sensing domain. (United States)

    Mishina, Yukiko; Mutoh, Hiroki; Knöpfel, Thomas


    Membrane proteins that respond to changes in transmembrane voltage are critical in regulating the function of living cells. The voltage-sensing domains (VSDs) of voltage-gated ion channels are extensively studied to elucidate voltage-sensing mechanisms, and yet many aspects of their structure-function relationship remain elusive. Here, we transplanted homologous amino acid motifs from the tetrameric voltage-activated potassium channel Kv3.1 to the monomeric VSD of Ciona intestinalis voltage-sensitive phosphatase (Ci-VSP) to explore which portions of Kv3.1 subunits depend on the tetrameric structure of Kv channels and which properties of Kv3.1 can be transferred to the monomeric Ci-VSP scaffold. By attaching fluorescent proteins to these chimeric VSDs, we obtained an optical readout to establish membrane trafficking and kinetics of voltage-dependent structural rearrangements. We found that motifs extending from 10 to roughly 100 amino acids can be readily transplanted from Kv3.1 into Ci-VSP to form engineered VSDs that efficiently incorporate into the plasma membrane and sense voltage. Some of the functional features of these engineered VSDs are reminiscent of Kv3.1 channels, indicating that these properties do not require interactions between Kv subunits or between the voltage sensing and the pore domains of Kv channels.

  7. Frequency-dependent capacitance-voltage and conductance-voltage characteristics of low-dielectric-constant SiOC(-H) thin films deposited by using plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Young; Lee, Heang Seuk; Woo, Jong Kwan; Choi, Chi Kyu; Lee, Kwang Man; Hyun, Myung Taek [Jeju National University, Jeju (Korea, Republic of); Navamathavan, Rangaswamy [Chonbuk National University, Chonju (Korea, Republic of)


    We report on the electrical characteristics of the metal-insulator-semiconductor (MIS) structure of low-dielectric-constant SiOC(-H) films. SiOC(-H) thin films were deposited on p-Si(100) substrates by using a plasma-enhanced chemical vapor deposition (PECVD) system. The frequency dependence of the capacitance-voltage (C-V) and the conductance-voltage (G/{omega}-V) characteristics of the A1/SiOC(-H)/p-Si(100)/Al MIS structures was analyzed. C-V and G/{omega}-V measurements were carried out over a frequency range of 1 kHz to 5 MHz. Based on our analysis, the C-V and the G/{omega}-V characteristics confirmed that the surface states and the series resistance were important parameters that strongly influenced the electrical properties of the A1/SiOC(-H)/p-Si(100)/Al MIS structures.

  8. Structural Dynamics of an Isolated-Voltage Sensor Domain in Lipid Bilayer (United States)

    Chakrapani, Sudha; Cuello, Luis G.; Cortes, Marien D.; Perozo, Eduardo


    Summary A strong interplay between the voltage-sensor domain (VSD) and the pore domain (PD) underlies voltage-gated channel functions. In a few voltage-sensitive proteins, the VSD has been shown to function without a canonical PD, although its structure and oligomeric state remain unknown. Here using EPR spectroscopy we show that the isolated-VSD of KvAP can remain monomeric in reconstituted bilayer and retain a transmembrane conformation. We find that water-filled crevices extend deep into the membrane around S3, a scaffold conducive to transport of proton/cations is intrinsic to the VSD. Differences in solvent accessibility in comparison to the full-length KvAP, allowed us to define an interacting footprint of the PD on the VSD. This interaction is centered around S1 and S2 and shows a rotation of 70–100° relative to Kv1.2-Kv2.1 chimera. Sequence-conservation patterns in Kv channels, Hv channels and voltage-sensitive phosphatases reveal several near-universal features suggesting a common molecular architecture for all VSDs. PMID:18334215

  9. Frequency and voltage dependence of electric and dielectric properties of Au/TiO2/n-4H-SiC (metal-insulator-semiconductor) type Schottky barrier diodes (United States)

    Tanrıkulu, E. E.; Yıldız, D. E.; Günen, A.; Altındal, Ş.


    The main electrical and dielectric properties of Au/TiO2/n-4H-SiC (MIS) type Schottky barrier diodes (SBDs) have been investigated as functions of frequency and applied bias voltage. We believe that the use of high dielectric interfacial layer between metal and semiconductor can improve the performance of Schottky diodes. From the experimental data, both electrical and dielectric parameters were found as strong function of frequency and applied bias voltage. The Fermi energy level (EF), the concentration of doping donor atoms (P), barrier height (ΦB) and series resistance (Rs) values were obtained from reverse and forward bias C-V characteristics. The changes in EF and ND with frequency are considerably low. Therefore, their values were taken at about constant. The real and imaginary parts of dielectric constant (\\varepsilon \\prime , \\varepsilon \\prime\\prime ), tangent loss (tanδ), ac electrical conductivity (σac), and real and imaginary parts of electric modulus (M‧ and M″) values were also obtained from reverse and forward bias C-V and G/ω-V characteristics. In addition, the voltage dependent profiles of all these electrical and dielectric parameters were drawn for each frequency. These results confirmed that both electrical and dielectric properties of Au/TiO2/n-4H-SiC (MIS) type SBD are quite sensitive to both the frequency and applied bias voltage due to surface polarization, density distribution of interface traps (Dit), and interfacial layer.

  10. Significance of the double-layer capacitor effect in polar rubbery dielectrics and exceptionally stable low-voltage high transconductance organic transistors (United States)

    Wang, Chao; Lee, Wen-Ya; Kong, Desheng; Pfattner, Raphael; Schweicher, Guillaume; Nakajima, Reina; Lu, Chien; Mei, Jianguo; Lee, Tae Hoon; Wu, Hung-Chin; Lopez, Jeffery; Diao, Ying; Gu, Xiaodan; Himmelberger, Scott; Niu, Weijun; Matthews, James R.; He, Mingqian; Salleo, Alberto; Nishi, Yoshio; Bao, Zhenan


    Both high gain and transconductance at low operating voltages are essential for practical applications of organic field-effect transistors (OFETs). Here, we describe the significance of the double-layer capacitance effect in polar rubbery dielectrics, even when present in a very low ion concentration and conductivity. We observed that this effect can greatly enhance the OFET transconductance when driven at low voltages. Specifically, when the polar elastomer poly(vinylidene fluoride-co-hexafluoropropylene) (e-PVDF-HFP) was used as the dielectric layer, despite a thickness of several micrometers, we obtained a transconductance per channel width 30 times higher than that measured for the same organic semiconductors fabricated on a semicrystalline PVDF-HFP with a similar thickness. After a series of detailed experimental investigations, we attribute the above observation to the double-layer capacitance effect, even though the ionic conductivity is as low as 10-10 S/cm. Different from previously reported OFETs with double-layer capacitance effects, our devices showed unprecedented high bias-stress stability in air and even in water.

  11. Low voltage and high ON/OFF ratio field-effect transistors based on CVD MoS2 and ultra high-k gate dielectric PZT. (United States)

    Zhou, Changjian; Wang, Xinsheng; Raju, Salahuddin; Lin, Ziyuan; Villaroman, Daniel; Huang, Baoling; Chan, Helen Lai-Wa; Chan, Mansun; Chai, Yang


    MoS2 and other atomic-level thick layered materials have been shown to have a high potential for outperforming Si transistors at the scaling limit. In this work, we demonstrate a MoS2 transistor with a low voltage and high ON/OFF ratio. A record small equivalent oxide thickness of ∼1.1 nm has been obtained by using ultra high-k gate dielectric Pb(Zr0.52Ti0.48)O3. The low threshold voltage (swing of 85.9 mV dec(-1), the high ON/OFF ratio of ∼10(8) and the negligible hysteresis ensure a high performance of the MoS2 transistor operating at 1 V. The extracted field-effect mobility of 1-10 cm(2) V(-1) s(-1) suggests a high crystalline quality of the CVD-grown MoS2 flakes. The combination of the two-dimensional layered semiconductor and the ultra high-k dielectric may enable the development of low-power electronic applications.

  12. Fully solution-processed low-voltage aqueous In2O3 thin-film transistors using an ultrathin ZrO(x) dielectric. (United States)

    Liu, Ao; Liu, Guo Xia; Zhu, Hui Hui; Xu, Feng; Fortunato, Elvira; Martins, Rodrigo; Shan, Fu Kai


    We reported here "aqueous-route" fabrication of In2O3 thin-film transistors (TFTs) using an ultrathin solution-processed ZrOx dielectric thin film. The formation and properties of In2O3 thin films under various annealing temperatures were intensively examined by thermogravimetric analysis, Fourier transform infrared spectroscopy, and atomic force microscopy. The solution-processed ZrOx thin film followed by sequential UV/ozone treatment and low-temperature thermal-annealing processes showed an amorphous structure, a low leakage-current density (∼1 × 10(-9) A/cm(2) at 2 MV/cm), and a high breakdown electric field (∼7.2 MV/cm). On the basis of its implementation as the gate insulator, the In2O3 TFTs based on ZrOx annealed at 250 °C exhibit an on/off current ratio larger than 10(7), a field-effect mobility of 23.6 cm(2)/V·s, a subthreshold swing of 90 mV/decade, a threshold voltage of 0.13 V, and high stability. These promising properties were obtained at a low operating voltage of 1.5 V. These results suggest that "aqueous-route" In2O3 TFTs based on a solution-processed ZrOx dielectric could potentially be used for low-cost, low-temperature-processing, high-performance, and flexible devices.

  13. Solution processed self-assembled monolayer gate dielectrics for low-voltage organic transistors. : Section Title: Electric Phenomena

    NARCIS (Netherlands)

    Ball, James; Wobkenberg, Paul H.; Colleaux, Florian; Kooistra, Floris B.; Hummelen, Jan C.; Bradley, Donal D. C.; Anthopoulos, Thomas D.


    Low-voltage org. transistors are sought for implementation in high vol. low-power portable electronics of the future. Here we assess the suitability of three phosphonic acid based self-assembling mols. for use as ultra-thin gate dielecs. in low-voltage soln. processable org. field-effect

  14. Performance and scalability of isolated DC-DC converter topologies in low voltage, high current applications

    Energy Technology Data Exchange (ETDEWEB)

    Vaisanen, V.


    Fuel cells are a promising alternative for clean and efficient energy production. A fuel cell is probably the most demanding of all distributed generation power sources. It resembles a solar cell in many ways, but sets strict limits to current ripple, common mode voltages and load variations. The typically low output voltage from the fuel cell stack needs to be boosted to a higher voltage level for grid interfacing. Due to the high electrical efficiency of the fuel cell, there is a need for high efficiency power converters, and in the case of low voltage, high current and galvanic isolation, the implementation of such converters is not a trivial task. This thesis presents galvanically isolated DC-DC converter topologies that have favorable characteristics for fuel cell usage and reviews the topologies from the viewpoint of electrical efficiency and cost efficiency. The focus is on evaluating the design issues when considering a single converter module having large current stresses. The dominating loss mechanism in low voltage, high current applications is conduction losses. In the case of MOSFETs, the conduction losses can be efficiently reduced by paralleling, but in the case of diodes, the effectiveness of paralleling depends strongly on the semiconductor material, diode parameters and output configuration. The transformer winding losses can be a major source of losses if the windings are not optimized according to the topology and the operating conditions. Transformer prototyping can be expensive and time consuming, and thus it is preferable to utilize various calculation methods during the design process in order to evaluate the performance of the transformer. This thesis reviews calculation methods for solid wire, litz wire and copper foil winding losses, and in order to evaluate the applicability of the methods, the calculations are compared against measurements and FEM simulations. By selecting a proper calculation method for each winding type, the winding

  15. A high voltage DC-DC converter driving a Dielectric Electro Active Polymer actuator for wind turbine flaps

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.;


    The Dielectric Electro Active Polymer (DEAP) material is a very thin (~80 μm) silicone elastomer film with a compliant metallic electrode layer on both sides. The DEAP is fundamentally a capacitor that is capable of very high strain. The property that the polymer changes its shape, as a result...

  16. Cost based reactive power participation for voltage control in multi units based isolated hybrid power system

    Directory of Open Access Journals (Sweden)

    Nitin Kumar Saxena


    Full Text Available Multi units of wind and diesel based generators in isolated hybrid power system have technical and operational advantages over single units system. They require dynamic reactive power compensation for fast recovery of voltage under load and input changes. In developing countries like India, investors’ prime concern is to provide continuous electricity at low rate while quality degradation can be permitted within pre defined acceptable range. The use of static compensator along with dynamic compensator may give cost effective reactive power participation for system. This paper presented pricing of reactive power compensation under steady state and transient conditions of system with fixed capacitor and STATCOM. The main contributions of the paper are; (i evaluating reactive power balance equation for generalized multi units of wind and diesel based isolated hybrid power system, (ii reactive power compensation using fixed capacitor and STATCOM in presence of composite load model, (ii fast recovery of voltage response using genetic algorithm based tuning of STATCOM controller, (iii evaluation of reactive power compensation cost for steady and dynamic conditions due to probabilistic change in load and/or input demand and (iv comparison of results with existing reference compensation method.

  17. Integrated high voltage power supply utilizing burst mode control and its performance impact on dielectric electro active polymer actuators

    DEFF Research Database (Denmark)

    Andersen, Thomas; Rødgaard, Martin Schøler; Andersen, Michael A. E.;

    a burst mode control technique. Controlling and driving a DEAP actuator between 250V to 2.5kV is demonstrated, where discrete like voltage change and voltage ripple is observed, which is introduced by the burst mode control. Measurements of the actuator strain-force reveal that the voltage ripples...... translates to small strain-force ripples. Nevertheless the driver demonstrates good capabilities of following an input reference signal, as well as having the size to fit inside a 110 mm x 32 mm cylindrical InLastor Push actuator, forming a “low voltage” DEAP actuator....

  18. Active and passive vibration isolation in piezoelectric phononic rods with external voltage excitation (United States)

    Zhang, Qicheng; Lan, Yu; Lu, Wei; Wang, Shuai


    Active piezoelectric materials are applied to one-dimensional phononic crystals, for the control of longitudinal vibration propagation both in active and passive modes. Based on the electromechanical coupling between the acoustical vibration and electric field, the electromechanical equivalent method is taken to theoretically predict the transmission spectrum of the longitudinal vibration. It is shown that the phononic rod can suppress the vibration efficiently at the frequencies of interest, by actively optimizing the motions of piezoelectric elements. In an illustrated phononic rod of 11.2cm long, active tunable isolations of more than 20dB at low frequencies (500Hz-14kHz) are generated by controlling the excitation voltages of piezoelectric elements. Meanwhile, passive fixed isolation at high frequencies (14k-63kHz) are presented by its periodicity characteristics. Finite element simulations and vibration experiments on the rod demonstrate the effectiveness of the approach in terms of its vibration isolation capabilities and tunable characteristics. This phononic rod can be manufactured easily and provides numerous potential applications in designing isolation mounts and platforms.

  19. Active and passive vibration isolation in piezoelectric phononic rods with external voltage excitation

    Directory of Open Access Journals (Sweden)

    Qicheng Zhang


    Full Text Available Active piezoelectric materials are applied to one-dimensional phononic crystals, for the control of longitudinal vibration propagation both in active and passive modes. Based on the electromechanical coupling between the acoustical vibration and electric field, the electromechanical equivalent method is taken to theoretically predict the transmission spectrum of the longitudinal vibration. It is shown that the phononic rod can suppress the vibration efficiently at the frequencies of interest, by actively optimizing the motions of piezoelectric elements. In an illustrated phononic rod of 11.2cm long, active tunable isolations of more than 20dB at low frequencies (500Hz-14kHz are generated by controlling the excitation voltages of piezoelectric elements. Meanwhile, passive fixed isolation at high frequencies (14k-63kHz are presented by its periodicity characteristics. Finite element simulations and vibration experiments on the rod demonstrate the effectiveness of the approach in terms of its vibration isolation capabilities and tunable characteristics. This phononic rod can be manufactured easily and provides numerous potential applications in designing isolation mounts and platforms.

  20. Parallel input parallel output high voltage bi-directional converters for driving dielectric electro active polymer actuators

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.;


    is to design and implement driving circuits for the DEAP actuators for their use in various applications. This paper presents implementation of parallel input, parallel output, high voltage (~2.5 kV) bi-directional DC-DC converters for driving the DEAP actuators. The topology is a bidirectional flyback DC......-DC converter incorporating commercially available high voltage MOSFETs (4 kV) and high voltage diodes (5 kV). Although the average current of the aforementioned devices is limited to 300 mA and 150 mA, respectively, connecting the outputs of multiple converters in parallel can provide a scalable design....... This enables operating the DEAP actuators in various static and dynamic applications e.g. positioning, vibration generation or damping, and pumps. The proposed idea is experimentally verified by connecting three high voltage converters in parallel to operate a single DEAP actuator. The experimental results...

  1. Digital control of a high-voltage (2.5 kV) bidirectional DC-DC converter for driving a dielectric electro active polymer (DEAP) based capacitive actuator

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.


    This paper presents a digital control technique toachieve valley switching in a bidirectional flyback converterused to drive a dielectric electro active polymer basedincremental actuator. The incremental actuator consists ofthree electrically isolated, mechanically connected capacitiveactuators. ...

  2. Whole-cell recordings of voltage-gated Calcium, Potassium and Sodium currents in acutely isolated hippocampal pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    Shuyun Huang; Qing Cai; Weitian Liu; Xiaoling Wang; Tao Wang


    Objective:To record Calcium, Potassium and Sodium currents in acutely isolated hippocampal pyramidal neurons. Methods:Hip-pocampal CA3 neurons were freshly isolated by 1 mg protease/3 ml SES and mechanical trituration with polished pipettes of progressively smaller tip diameters. Patch clamp technique in whole-cell mode was employed to record voltage-gated channel currents. Results:The procedure dissociated hippocampal neurons, preserving apical dendrites and several basal dendrites, without impairing the electrical characteristics of the neurons. Whole-cell patch clamp configuration was successfully used to record voltage-gated Ca2+ currents, delayed rectifier K+ current and voltage-gated Na+ currents. Conclusion:Protease combined with mechanical trituration may be used for the dissociation of neurons from rat hippocampus. Voltage-gated channels currents could be recorded using a patch clamp technique.

  3. Frequency and voltage dependence dielectric properties, ac electrical conductivity and electric modulus profiles in Al/Co{sub 3}O{sub 4}-PVA/p-Si structures

    Energy Technology Data Exchange (ETDEWEB)

    Bilkan, Çiğdem, E-mail: [Department of Physics, Faculty of Sciences, The University of Çankırı Karatekin, 18100 Çankırı (Turkey); Azizian-Kalandaragh, Yashar [Department of Physics, Faculty of Science, The University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Altındal, Şemsettin [Department of Physics, Faculty of Sciences, The University of Gazi, 06500 Ankara (Turkey); Shokrani-Havigh, Roya [Department of Physics, Faculty of Science, The University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of)


    In this research a simple microwave-assisted method have been used for preparation of cobalt oxide nanostructures. The as-prepared sample has been investigated by UV–vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM). On the other hand, frequency and voltage dependence of both the real and imaginary parts of dielectric constants (ε′, ε″) and electric modulus (M′ and M″), loss tangent (tanδ), and ac electrical conductivity (σ{sub ac}) values of Al/Co{sub 3}O{sub 4}-PVA/p-Si structures were obtained in the wide range of frequency and voltage using capacitance (C) and conductance (G/ω) data at room temperature. The values of ε′, ε″ and tanδ were found to decrease with increasing frequency almost for each applied bias voltage, but the changes in these parameters become more effective in the depletion region at low frequencies due to the charges at surface states and their relaxation time and polarization effect. While the value of σ is almost constant at low frequency, increases almost as exponentially at high frequency which are corresponding to σ{sub dc} and σ{sub ac}, respectively. The M′ and M″ have low values at low frequencies region and then an increase with frequency due to short-range mobility of charge carriers. While the value of M′ increase with increasing frequency, the value of M″ shows two peak and the peaks positions shifts to higher frequency with increasing applied voltage due to the decrease of the polarization and N{sub ss} effects with increasing frequency.

  4. Frequency and voltage dependence dielectric properties, ac electrical conductivity and electric modulus profiles in Al/Co3O4-PVA/p-Si structures (United States)

    Bilkan, Çiğdem; Azizian-Kalandaragh, Yashar; Altındal, Şemsettin; Shokrani-Havigh, Roya


    In this research a simple microwave-assisted method have been used for preparation of cobalt oxide nanostructures. The as-prepared sample has been investigated by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM). On the other hand, frequency and voltage dependence of both the real and imaginary parts of dielectric constants (ε‧, ε″) and electric modulus (M‧ and M″), loss tangent (tanδ), and ac electrical conductivity (σac) values of Al/Co3O4-PVA/p-Si structures were obtained in the wide range of frequency and voltage using capacitance (C) and conductance (G/ω) data at room temperature. The values of ε‧, ε″ and tanδ were found to decrease with increasing frequency almost for each applied bias voltage, but the changes in these parameters become more effective in the depletion region at low frequencies due to the charges at surface states and their relaxation time and polarization effect. While the value of σ is almost constant at low frequency, increases almost as exponentially at high frequency which are corresponding to σdc and σac, respectively. The M‧ and M″ have low values at low frequencies region and then an increase with frequency due to short-range mobility of charge carriers. While the value of M‧ increase with increasing frequency, the value of M″ shows two peak and the peaks positions shifts to higher frequency with increasing applied voltage due to the decrease of the polarization and Nss effects with increasing frequency.

  5. Aqueous Solution-Deposited Gallium Oxide Dielectric for Low-Temperature, Low-Operating-Voltage Indium Oxide Thin-Film Transistors: A Facile Route to Green Oxide Electronics. (United States)

    Xu, Wangying; Cao, Hongtao; Liang, Lingyan; Xu, Jian-Bin


    We reported a novel aqueous route to fabricate Ga2O3 dielectric at low temperature. The formation and properties of Ga2O3 were investigated by a wide range of characterization techniques, revealing that Ga2O3 films could effectively block leakage current even after annealing in air at 200 °C. Furthermore, all aqueous solution-processed In2O3/Ga2O3 TFTs fabricated at 200 and 250 °C showed mobilities of 1.0 and 4.1 cm2 V(-1) s(-1), on/off current ratio of ∼10(5), low operating voltages of 4 V, and negligible hysteresis. Our study represents a significant step toward the development of low-cost, low-temperature, and large-area green oxide electronics.

  6. Plasma density enhancement in atmospheric-pressure dielectric-barrier discharges by high-voltage nanosecond pulse in the pulse-on period: a PIC simulation (United States)

    Sang, Chaofeng; Sun, Jizhong; Wang, Dezhen


    A particle-in-cell (PIC) plus Monte Carlo collision simulation is employed to investigate how a sustainable atmospheric pressure single dielectric-barrier discharge responds to a high-voltage nanosecond pulse (HVNP) further applied to the metal electrode. The results show that the HVNP can significantly increase the plasma density in the pulse-on period. The ion-induced secondary electrons can give rise to avalanche ionization in the positive sheath, which widens the discharge region and enhances the plasma density drastically. However, the plasma density stops increasing as the applied pulse lasts over certain time; therefore, lengthening the pulse duration alone cannot improve the discharge efficiency further. Physical reasons for these phenomena are then discussed.

  7. Formation of combined partially recessed and multiple fluorinated-dielectric layers gate structures for high threshold voltage GaN-based HEMT power devices (United States)

    Huang, Huolin; Liang, Yung Chii


    The formation of partial AlGaN trench recess filled with multiple fluorinated gate dielectric layers as metal-insulator-semiconductor (MIS) gate structure for GaN-based HEMT power devices is designed, fabricated and experimentally verified. The approach realizes the device normally-off operational mode and at the same time is able to preserve the good mobility in the 2DEG channel for a maximum on-state current. Experimental measurements on the fabricated MIS-HEMT devices indicate a high gate threshold voltage (Vth) at around 5 V and a very low gate leakage current at pA/mm level. This proposed gate structure provides very promising properties for GaN-based power semiconductor devices in future power electronics switching applications.

  8. The action of a phorbol ester on voltage-dependent parameters of the sodium current in isolated hippocampal neurons. (United States)

    Chizhmakov, I V; Klee, M R


    The action of a phorbol ester (phorbol-12,13-diacetate) on the voltage-activated sodium current has been investigated by the voltage-clamp method in acutely isolated pyramidal neurons from rat hippocampus. The intracellular perfusion of isolated pyramidal neurons for 30-40 min induced a gradual 10-15 mV shift in both the current-voltage relationship and voltage-dependent steady-state inactivation to more negative potentials. The application of phorbol ester (1-10 microM) to isolated neurons for the same time increased the amplitude of sodium current by 15-20%, shifted the above-mentioned voltage-dependent parameters for an additional 10-15 mV in the same direction and changed the slope of the steady-state inactivation curve. In contrast, after prolonged incubation of slices in the phorbol ester-containing solution (1-10 microM) for 0.5-3 h, subsequent application of phorbol ester at the same concentration caused neither the addition shift of the voltage-dependent characteristics of sodium channels nor the change of the slope of the steady-state inactivation curve. However, in this case an increase in the amplitude of sodium current by 15-20% during 30-40 min intracellular perfusion was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Recycling ``in situ`` of dielectric oil of electric transformer of medium and high voltage; Reciclaje ``in situ`` y ``en carga`` del aceite dielectrico de los transformadores electricos de media y alta tension

    Energy Technology Data Exchange (ETDEWEB)

    Solis, A.


    The author describes the process followed by the company to control the quality of every type of oil from electric transformer of medium and high voltage polluted because of its use. The pollutants contained in the dielectric liquid are eliminated or minimize through the following treatments: conditioning-reconditioning-regeneration. (Author) 6 refs.

  10. A design of High-precision High-Voltage Fiber-Optic Analog Signal Isolation Converter

    Institute of Scientific and Technical Information of China (English)

    李建伟; 许留伟; 刘小宁; 杨雷


    This paper introduces a design of high-prectison high-voltage fiber-optic analog sig-nal isoaltion converter based on the technology of Voltage-to-Fequency (V/F)and Frequency -to Voltage(F/V) conversion It describes the principle ,system configuration and hardware design

  11. New non-linear control strategy for non-isolated DC/DC converter with high voltage ratio

    Energy Technology Data Exchange (ETDEWEB)

    Shahin, A.; Huang, B.; Martin, J.P.; Pierfederici, S.; Davat, B. [Groupe de Recherche en Electronique et en Electrotechnique de Nancy - INPL - Nancy Universite, 2, Avenue de la Foret de Haye, 54516 Vandoeuvre-les-Nancy Cedex (France)


    In this paper, a non-isolated DC/DC converter with high voltage ratio is proposed to allow the interface between a low voltage power source like fuel cell and a high voltage DC bus. To take into account the low voltage-high density characteristics of power sources, a cascaded structure composed of two sub-converters has been chosen and allows obtaining a high voltage ratio. The choice of each sub-converter is based on the requirements of the source and its performances. Consequently, we have chosen a three-interleaved boost converter as the 1st sub-converter whereas the 2nd sub-converter is a three-level boost converter. The control of the whole system is realized thanks to energetic trajectories planning based on flatness properties of the system. The control of both the current and the balance of voltage across the output serial capacitors of the three-level boost converter is ensured by non-linear controllers based on a new non-linear model. Experimental results allow validating the proposed power architecture and its associated control. (author)

  12. High-Efficiency Isolated Boost DCDC Converter for High-Power Low-Voltage Fuel-Cell Applications

    DEFF Research Database (Denmark)

    Nymand, Morten; Andersen, Michael A. E.


    A new design approach achieving very high conversion efficiency in low-voltage high-power isolated boost dc-dc converters is presented. The transformer eddy-current and proximity effects are analyzed, demonstrating that an extensive interleaving of primary and secondary windings is needed to avoid...... high winding losses. The analysis of transformer leakage inductance reveals that extremely low leakage inductance can be achieved, allowing stored energy to be dissipated. Power MOSFETs fully rated for repetitive avalanches allow primary-side voltage clamp circuits to be eliminated. The oversizing...

  13. Neural network-based voltage regulator for an isolated asynchronous generator supplying three-phase four-wire loads

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Bhim; Kasal, Gaurav Kumar [Department of Electrical Engineering, Indian Institute of Technology, Delhi, Hauz-Khas, New Delhi 110016 (India)


    This paper deals with a neural network-based solid state voltage controller for an isolated asynchronous generator (IAG) driven by constant speed prime mover like diesel engine, bio-gas or gasoline engine and supplying three-phase four-wire loads. The proposed control scheme uses an indirect current control and a fast adaptive linear element (adaline) based neural network reference current extractor, which extracts the real positive sequence current component without any phase shift. The neutral current of the source is also compensated by using three single-phase bridge configuration of IGBT (insulated gate bipolar junction transistor) based voltage source converter (VSC) along-with single-phase transformer having self-supported dc bus. The proposed controller provides the functions as a voltage regulator, a harmonic eliminator, a neutral current compensator, and a load balancer. The proposed isolated electrical system with its controller is modeled and simulated in MATLAB along with Simulink and PSB (Power System Block set) toolboxes. The simulated results are presented to demonstrate the capability of an isolated asynchronous generating system driven by a constant speed prime mover for feeding three-phase four-wire loads. (author)

  14. A surface plasmon resonance approach to monitor toxin interactions with an isolated voltage-gated sodium channel paddle motif. (United States)

    Martin-Eauclaire, Marie-France; Ferracci, Géraldine; Bosmans, Frank; Bougis, Pierre E


    Animal toxins that inhibit voltage-gated sodium (Na(v)) channel fast inactivation can do so through an interaction with the S3b-S4 helix-turn-helix region, or paddle motif, located in the domain IV voltage sensor. Here, we used surface plasmon resonance (SPR), an optical approach that uses polarized light to measure the refractive index near a sensor surface to which a molecule of interest is attached, to analyze interactions between the isolated domain IV paddle and Na(v) channel-selective α-scorpion toxins. Our SPR analyses showed that the domain IV paddle can be removed from the Na(v) channel and immobilized on sensor chips, and suggest that the isolated motif remains susceptible to animal toxins that target the domain IV voltage sensor. As such, our results uncover the inherent pharmacological sensitivities of the isolated domain IV paddle motif, which may be exploited to develop a label-free SPR approach for discovering ligands that target this region.

  15. Isolated PWM DC-AC SICAM with an active capacitive voltage clamp[Pulse Density Modulated; Pulse Width Modulation

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.


    In this report an isolated PWM DC-AC SICAM with an active capacitive voltage clamp is presented. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitors and possibly with an EMC filter on the mains entrance. Isolation from the AC mains is achieved using a high frequency (HF) transformer, whose voltages are not audio-modulated. The latter simplifies the design and is expected to have many advantages over the approach where the transformer voltages are modulated in regards to the audio signal reference. Input stage is built as a DC-AC inverter (push-pull, half-bridge or a full-bridge) and operated with 50% duty cycle, with all the challenges to avoid transformer saturation and obtain symmetrical operation. On the secondary side the output section is implemented as rectifier+inverter AC-AC stage, i.e. a true bidirectional bridge, which operation is aimed towards amplification of the audio signal. In order to solve the problem with the commutation of the load current, a dead time between the incoming and outgoing bidirectional switch is implemented, while a capacitive voltage clamp is used to keep the induced overvoltage to reasonable levels. The energy stored in the clamping capacitor is not wasted as in the dissipative clamps, but is rather transferred back to the primary side for further processing using an auxiliary isolated single-switch converter, i.e. an active clamping technique is used. (au)

  16. Low-voltage back-gated atmospheric pressure chemical vapor deposition based graphene-striped channel transistor with high-κ dielectric showing room-temperature mobility > 11,000 cm(2)/V·s. (United States)

    Smith, Casey; Qaisi, Ramy; Liu, Zhihong; Yu, Qingkai; Hussain, Muhammad Mustafa


    Utilization of graphene may help realize innovative low-power replacements for III-V materials based high electron mobility transistors while extending operational frequencies closer to the THz regime for superior wireless communications, imaging, and other novel applications. Device architectures explored to date suffer a fundamental performance roadblock due to lack of compatible deposition techniques for nanometer-scale dielectrics required to efficiently modulate graphene transconductance (gm) while maintaining low gate capacitance-voltage product (CgsVgs). Here we show integration of a scaled (10 nm) high-κ gate dielectric aluminum oxide (Al2O3) with an atmospheric pressure chemical vapor deposition (APCVD)-derived graphene channel composed of multiple 0.25 μm stripes to repeatedly realize room-temperature mobility of 11,000 cm(2)/V·s or higher. This high performance is attributed to the APCVD graphene growth quality, excellent interfacial properties of the gate dielectric, conductivity enhancement in the graphene stripes due to low tox/Wgraphene ratio, and scaled high-κ dielectric gate modulation of carrier density allowing full actuation of the device with only ±1 V applied bias. The superior drive current and conductance at Vdd = 1 V compared to other top-gated devices requiring undesirable seed (such as aluminum and poly vinyl alcohol)-assisted dielectric deposition, bottom gate devices requiring excessive gate voltage for actuation, or monolithic (nonstriped) channels suggest that this facile transistor structure provides critical insight toward future device design and process integration to maximize CVD-based graphene transistor performance.

  17. Low-voltage back-gated atmospheric pressure chemical vapor deposition based graphene-striped channel transistor with high-κ dielectric showing room-temperature mobility > 11 000 cm2/V·s

    KAUST Repository

    Smith, Casey


    Utilization of graphene may help realize innovative low-power replacements for III-V materials based high electron mobility transistors while extending operational frequencies closer to the THz regime for superior wireless communications, imaging, and other novel applications. Device architectures explored to date suffer a fundamental performance roadblock due to lack of compatible deposition techniques for nanometer-scale dielectrics required to efficiently modulate graphene transconductance (gm) while maintaining low gate capacitance-voltage product (CgsVgs). Here we show integration of a scaled (10 nm) high-κ gate dielectric aluminum oxide (Al2O3) with an atmospheric pressure chemical vapor deposition (APCVD)-derived graphene channel composed of multiple 0.25 μm stripes to repeatedly realize room-temperature mobility of 11 000 cm 2/V·s or higher. This high performance is attributed to the APCVD graphene growth quality, excellent interfacial properties of the gate dielectric, conductivity enhancement in the graphene stripes due to low t ox/Wgraphene ratio, and scaled high-κ dielectric gate modulation of carrier density allowing full actuation of the device with only ±1 V applied bias. The superior drive current and conductance at Vdd = 1 V compared to other top-gated devices requiring undesirable seed (such as aluminum and poly vinyl alcohol)-assisted dielectric deposition, bottom gate devices requiring excessive gate voltage for actuation, or monolithic (nonstriped) channels suggest that this facile transistor structure provides critical insight toward future device design and process integration to maximize CVD-based graphene transistor performance. © 2013 American Chemical Society.

  18. Low-voltage polymer thin-film transistors with high-k HfTiO gate dielectric annealed in NH3 or N2


    Choi, HW; Lai, PT; Xu, JP; Deng, LF; Liu, YR


    OTFTs with P3HT as organic semiconductor and HfTiO as gate dielectric have been studied in this work. The HfTiO dielectric film was prepared by RF sputtering of Hf and DC sputtering of Ti at room temperature. Subsequently, the dielectric film was annealed in an NH3 or N2 ambient at 200 °C. Then a layer of OTS was deposited by spin-coating method to improve the surface characteristics of the gate dielectric. Afterwards, P3HT was deposited by spin-coating method. The OTFTs were characterized by...

  19. Influence of back-gate stress on the back-gate threshold voltage of a LOCOS-isolated SOI MOSFET

    Institute of Scientific and Technical Information of China (English)

    梅博; 毕津顺; 李多力; 刘思南; 韩郑生


    The performance of a LOCOS-isolated SOI MOSFET heavily depends on its back-gate characteristic, which can be affected by back-gate stress,A large voltage stress was applied to the back gate of SOI devices for at least 30 s at room temperature,which could effectively modify the back-gate threshold voltage of these devices.This modification is stable and time invariant.In order to improve the back-gate threshold voltage,positive substrate bias was applied to NMOS devices and negative substrate bias was applied to PMOS devices,These results suggest that there is a leakage path between source and drain along the silicon island edge,and the application of large backgate bias with the source,drain and gate grounded can strongly affect this leakage path.So we draw the conclusion that the back-gate threshold voltage,which is directly related to the leakage current,can be influenced by back-gate stress.

  20. Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on dipolar copolymers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede;


    Dielectric elastomers (DES) are a promising new transducer technology, but high driving voltages limit their current commercial potential. One method used to lower driving voltage is to increase dielectric permittivity of the elastomer. A novel silicone elastomer system with high dielectric permi......-4-nitrobenzene. Here, a high increase in dielectric permittivity (similar to 70%) was obtained without compromising other favourable DE properties such as elastic modulus, gel fraction, dielectric loss and electrical breakdown strength. © 2014 Elsevier Ltd. All rights reserved....

  1. Experimental investigation of streamer affinity for dielectric surfaces

    NARCIS (Netherlands)

    Trienekens, D.J.M.; Nijdam, S.; Akkermans, G.; Plompen, I.; Christen, T.; Ebert, U.


    We have experimentally investigated the affinity of streamers for dielectric surfaces using stroboscopic imaging and stereo photography. Affinity of streamers for dielectric surfaces was found to depend on a wide set of parameters, including pressure, voltage, dielectric material and di

  2. NMR investigation of the isolated second voltage-sensing domain of human Nav1.4 channel. (United States)

    Paramonov, A S; Lyukmanova, E N; Myshkin, M Yu; Shulepko, M A; Kulbatskii, D S; Petrosian, N S; Chugunov, A O; Dolgikh, D A; Kirpichnikov, M P; Arseniev, A S; Shenkarev, Z O


    Voltage-gated Na(+) channels are essential for the functioning of cardiovascular, muscular, and nervous systems. The α-subunit of eukaryotic Na(+) channel consists of ~2000 amino acid residues and encloses 24 transmembrane (TM) helices, which form five membrane domains: four voltage-sensing (VSD) and one pore domain. The structural complexity significantly impedes recombinant production and structural studies of full-sized Na(+) channels. Modular organization of voltage-gated channels gives an idea for studying of the isolated second VSD of human skeletal muscle Nav1.4 channel (VSD-II). Several variants of VSD-II (~150a.a., four TM helices) with different N- and C-termini were produced by cell-free expression. Screening of membrane mimetics revealed low stability of VSD-II samples in media containing phospholipids (bicelles, nanodiscs) associated with the aggregation of electrically neutral domain molecules. The almost complete resonance assignment of (13)C,(15)N-labeled VSD-II was obtained in LPPG micelles. The secondary structure of VSD-II showed similarity with the structures of bacterial Na(+) channels. The fragment of S4 TM helix between the first and second conserved Arg residues probably adopts 310-helical conformation. Water accessibility of S3 helix, observed by the Mn(2+) titration, pointed to the formation of water-filled crevices in the micelle embedded VSD-II. (15)N relaxation data revealed characteristic pattern of μs-ms time scale motions in the VSD-II regions sharing expected interhelical contacts. VSD-II demonstrated enhanced mobility at ps-ns time scale as compared to isolated VSDs of K(+) channels. These results validate structural studies of isolated VSDs of Na(+) channels and show possible pitfalls in application of this 'divide and conquer' approach.

  3. High-Performance Harmonic Isolation and Load Voltage Regulation of the Three-Phase Series Active Filter Utilizing the Waveform Reconstruction Method

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Hava, Ahmet M.


    . The SAF-compensated system utilizing WRM provides highperformance load harmonic voltage isolation and load voltage regulation at steady-state and during transients compared to the system utilizing the synchronous reference-frame-based signal decomposition. In addition, reducing the line current sampling......This paper develops a waveform reconstruction method (WRM) for high accuracy and bandwidth signal decomposition of voltage-harmonic-type three-phase diode rectifier load voltage into its harmonic and fundamental components, which are utilized in the series active filter (SAF) control algorithms...

  4. 串级式电压互感器铁磁谐振对介损试验的影响%The influence of ferro-resonance phenomenon of cascade-type voltage transformer on dielectric loss test

    Institute of Scientific and Technical Information of China (English)



    针对关帝变电站220 kVⅠ号母线电压互感器在介质损耗因数测量时试验数据漂移的问题,从铁磁谐振原理出发,分析了串级式电压互感器铁磁谐振对介质损耗因数测量的影响,提出合理可行的解决方案。应用结果表明:通过自备发电机对仪器电压源供电,是一种简单而有效的解决方法。%Aiming at the problem of the test data occur shift when dielectric loss factor measurement of voltage transformer of 220 kVⅠbus bar in Guandi Substation, based on principle of ferro-reso-nance, analyzes the influence of ferro-resonance phenomenon of cascade type voltage transformer on dielectric loss factor measurement, puts forward feasible solution.The application result shows that it is a simple and effective solution using standby dynamo supply voltage source to the test instrument.

  5. Temperature dependence of the dielectric constant of acrylic dielectric elastomer

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Junjie; Chen, Hualing; Li, Bo; Chang, Longfei [Xi' an Jiaotong University, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an (China); Xi' an Jiaotong University, School of Mechanical Engineering, Xi' an (China)


    The dielectric constant is an essential electrical parameter to the achievable voltage-induced deformation of the dielectric elastomer. This paper primarily focuses on the temperature dependence of the dielectric constant (within the range of 173 K to 373 K) for the most widely used acrylic dielectric elastomer (VHB 4910). First the dielectric constant was investigated experimentally with the broadband dielectric spectrometer (BDS). Results showed that the dielectric constant first increased with temperature up to a peak value and then dropped to a relative small value. Then by analyzing the fitted curves, the Cole-Cole dispersion equation was found better to characterize the rising process before the peak values than the Debye dispersion equation, while the decrease process afterward can be well described by the simple Debye model. Finally, a mathematical model of dielectric constant of VHB 4910 was obtained from the fitted results which can be used to further probe the electromechanical stability of the dielectric elastomers. (orig.)

  6. Solution structure and phospholipid interactions of the isolated voltage-sensor domain from KvAP. (United States)

    Butterwick, Joel A; MacKinnon, Roderick


    Voltage-sensor domains (VSDs) are specialized transmembrane segments that confer voltage sensitivity to many proteins such as ion channels and enzymes. The activities of these domains are highly dependent on both the chemical properties and the physical properties of the surrounding membrane environment. To learn about VSD-lipid interactions, we used nuclear magnetic resonance spectroscopy to determine the structure and phospholipid interface of the VSD from the voltage-dependent K(+) channel KvAP (prokaryotic Kv from Aeropyrum pernix). The solution structure of the KvAP VSD solubilized within phospholipid micelles is similar to a previously determined crystal structure solubilized by a nonionic detergent and complexed with an antibody fragment. The differences observed include a previously unidentified short amphipathic α-helix that precedes the first transmembrane helix and a subtle rigid-body repositioning of the S3-S4 voltage-sensor paddle. Using (15)N relaxation experiments, we show that much of the VSD, including the pronounced kink in S3 and the S3-S4 paddle, is relatively rigid on the picosecond-to-nanosecond timescale. In contrast, the kink in S3 is mobile on the microsecond-to-millisecond timescale and may act as a hinge in the movement of the paddle during channel gating. We characterized the VSD-phospholipid micelle interactions using nuclear Overhauser effect spectroscopy and showed that the micelle uniformly coats the KvAP VSD and approximates the chemical environment of a phospholipid bilayer. Using paramagnetically labeled phospholipids, we show that bilayer-forming lipids interact with the S3 and S4 helices more strongly than with S1 and S2.

  7. High-voltage isolation transformer for sub-nanosecond rise time pulses constructed with annular parallel-strip transmission lines. (United States)

    Homma, Akira


    A novel annular parallel-strip transmission line was devised to construct high-voltage high-speed pulse isolation transformers. The transmission lines can easily realize stable high-voltage operation and good impedance matching between primary and secondary circuits. The time constant for the step response of the transformer was calculated by introducing a simple low-frequency equivalent circuit model. Results show that the relation between the time constant and low-cut-off frequency of the transformer conforms to the theory of the general first-order linear time-invariant system. Results also show that the test transformer composed of the new transmission lines can transmit about 600 ps rise time pulses across the dc potential difference of more than 150 kV with insertion loss of -2.5 dB. The measured effective time constant of 12 ns agreed exactly with the theoretically predicted value. For practical applications involving the delivery of synchronized trigger signals to a dc high-voltage electron gun station, the transformer described in this paper exhibited advantages over methods using fiber optic cables for the signal transfer system. This transformer has no jitter or breakdown problems that invariably occur in active circuit components.

  8. 高压脉冲电参数对果蔬介电特性的影响机理分析%Influence Mechanism of High-voltage Pulsed Electric Parameters on Dielectric Properties of Fruits and Vegetables

    Institute of Scientific and Technical Information of China (English)

    马飞宇; 郭玉明


    The high voltage pulse electric field pretreatment can improve the freeze-drying rate of fruits and vegetables and reduce energy consumption .But when researching fruit and vegetable dielectric property about the changes of on -line monitoring freeze-dried moisture content ,high-voltage pulsed electric field should be considered the influence of electri-cal parameter on dielectric properties of fruit and vegetable .In the cellular level , high-voltage pulsed electric fields effects fruits and vegetables , analyzing the influence of electric parameters on dielectric properties of fruit and vegetable . For equivalent circuit model of fruits and vegetables biological tissue , electrical parameters influence on dielectric proper-ties of fruit and vegetable , such as fruit and vegetable equivalent capacitance and equivalent impedance , which were summarized and analyzed about mechanism to provide a reference on high voltage pulse electric field pretreatment fruit and vegetable processing parameters optimization .%高压脉冲电场预处理果蔬可以提高果蔬冻干速率、降低能耗。但研究运用果蔬介电特性在线监测冻干水分变化时,需要考虑高压脉冲电场电参数对果蔬介电特性的影响。为此,针对高压脉冲电场作用果蔬细胞层面,分析了电参数对果蔬介电特性的影响,对果蔬生物组织等效电路模型和电参数对果蔬等效电容、等效阻抗等介电特性的影响等方面进行了综述分析及机理分析,为高压脉冲电场预处理果蔬工艺参数优化提供了参考。

  9. Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on tunable functionalized copolymers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede;


    High driving voltages currently limit the commercial potential of dielectric elastomers (DEs). One method used to lower driving voltage is to increase dielectric permittivity of the elastomer. A novel silicone elastomer system with high dielectric permittivity was prepared through the synthesis o...

  10. Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on tunable functionalized copolymers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede


    High driving voltages currently limit the commercial potential of dielectric elastomers (DEs). One method used to lower driving voltage is to increase dielectric permittivity of the elastomer. A novel silicone elastomer system with high dielectric permittivity was prepared through the synthesis o...

  11. Ultra-wideband electronics, design methods, algorithms, and systems for dielectric spectroscopy of isolated B16 tumor cells in liquid medium (United States)

    Maxwell, Erick N.

    Quantifying and characterizing isolated tumor cells (ITCs) is of interest in surgical pathology and cytology for its potential to provide data for cancer staging, classification, and treatment. Although the independent prognostic significance of circulating ITCs has not been proven, their presence is gaining clinical relevance as an indicator. However, researchers have not established an optimal method for detecting ITCs. Consequently, this Ph.D. dissertation is concerned with the development and evaluation of dielectric spectroscopy as a low-cost method for cell characterization and quantification. In support of this goal, ultra-wideband (UWB), microwave pulse generator circuits, coaxial transmission line fixtures, permittivity extraction algorithms, and dielectric spectroscopy measurement systems were developed for evaluating the capacity to quantify B16-F10 tumor cells in suspension. First, this research addressed challenges in developing tunable UWB circuits for pulse generation. In time-domain dielectric spectroscopy, a tunable UWB pulse generator facilitates exploration of microscopic dielectric mechanisms, which contribute to dispersion characteristics. Conventional approaches to tunable pulse generator design have resulted in complex circuit topologies and unsymmetrical waveform morphologies. In this research, a new design approach for low-complexity, tunable, sub-nanosecond and UWB pulse generator was developed. This approach was applied to the development of a novel generator that produces symmetrical waveforms (patent pending 60/597,746). Next, this research addressed problems with transmission-reflection (T/R) measurement of cell suspensions. In T/R measurement, coaxial transmission line fixtures have historically required an elaborate sample holder for containing liquids, resulting in high cost and complexity. Furthermore, the algorithms used to extract T/R dielectric properties have suffered from myriad problems including local minima and

  12. Membrane potential measurements of isolated neurons using a voltage-sensitive dye.

    Directory of Open Access Journals (Sweden)

    Richard Fairless

    Full Text Available The ability to monitor changes in membrane potential is a useful tool for studying neuronal function, but there are only limited options available at present. Here, we have investigated the potential of a commercially available FLIPR membrane potential (FMP dye, developed originally for high throughput screening using a plate reader, for imaging the membrane potential of cultured cells using an epifluorescence-based single cell imaging system. We found that the properties of the FMP dye make it highly suitable for such imaging since 1 its fluorescence displayed a high signal-to-noise ratio, 2 robust signals meant only minimal exposure times of around 5 ms were necessary, and 3 bidirectional changes in fluorescence were detectable resulting from hyper- or depolarising conditions, reaching equilibrium with a time constant of 4-8 s. Measurements were possible independently of whether membrane potential changes were induced by voltage clamping, or manipulating the ionic distribution of either Na(+ or K(+. Since FMP behaves as a charged molecule which accumulates in the cytosol, equations based on the Boltzmann distribution were developed determining that the apparent charge of FMP which represents a measure of the voltage sensitivity of the dye, is between -0.62 and -0.72. Finally, we demonstrated that FMP is suitable for use in a variety of neuronal cell types and detects membrane potential changes arising from spontaneous firing of action potentials and through stimulation with a variety of excitatory and inhibitory neurotransmitters.

  13. 4Nx Non-Isolated and Non-Inverting Hybrid Interleaved Multilevel Boost Converter Based on VLCIm Cell and Cockroft Walton Voltage Multiplier for Renewable Energy Applications

    DEFF Research Database (Denmark)

    Bhaskar, Mahajan Sagar; Padmanaban, Sanjeevikumar; Blaabjerg, Frede


    In this treatise, 4Nx hybrid Non Inverting & Non Isolated (NI-NI) DC-DC interleaved multi-level boost converter (4Nx IMBC) for renewable energy applications is proposed. The proposed 4Nx IMBC is derived by coalescing the feature of 2Nx DC-DC Interleaved Multi-level Boost Converter (2Nx IMBC......), voltage-lift-switched-inductor-modified (VLSlm Cell) and Cockcroft Walton (CW) voltage multipliers. The 4Nx converter provides 4N times more conversion voltage ratio compared to conventional boost converter where N denotes the number of output stages of the 4Nx IMBC. To make renewable energy sources...

  14. Dielectric elastomers, with very high dielectric permittivity, based on silicone and ionic interpenetrating networks

    DEFF Research Database (Denmark)

    Yu, Liyun; Madsen, Frederikke Bahrt; Hvilsted, Søren;


    Dielectric elastomers (DEs), which represent an emerging actuator and generator technology, admittedly have many favourable properties, but their high driving voltages are one of the main obstacles to commercialisation. One way to reduce driving voltage is by increasing the ratio between dielectr...... as well as relatively high breakdown strength. All IPNs have higher dielectric losses than pure silicone elastomers, but when accounting for this factor, IPNs still exhibit satisfactory performance improvements....... is demonstrated herein, and a number of many and important parameters, such as dielectric permittivity/loss, viscoelastic properties and dielectric breakdown strength, are investigated. Ionic and silicone elastomer IPNs are promising prospects for dielectric elastomer actuators, since very high permittivities......Dielectric elastomers (DEs), which represent an emerging actuator and generator technology, admittedly have many favourable properties, but their high driving voltages are one of the main obstacles to commercialisation. One way to reduce driving voltage is by increasing the ratio between dielectric...

  15. Scorpion toxin prolongs an inactivation phase of the voltage-dependent sodium current in rat isolated single hippocampal neurons. (United States)

    Kaneda, M; Oyama, Y; Ikemoto, Y; Akaike, N


    The effects of scorpion toxin on the voltage-dependent sodium current (INa) of CA1 pyramidal neurons isolated from rat hippocampus were studied under the single-electrode voltage-clamp condition using a 'concentration-clamp' technique. The toxin increased the peak amplitude of INa and prolonged its inactivation phase in a time- and dose-dependent manner. Inactivation phase of INa proceeded with two exponential components in the absence (control) and presence of the toxin. In the toxin-treated neurons, both the time constant of slow component and its fractional contribution to the total current increased dose-dependently while the fractional contribution of the fast one decreased in a dose-dependent fashion without changing its time constant. Actions of scorpion toxin on the sodium channels of hippocampal pyramidal neurons were essentially similar to those of peripheral preparations. Therefore, it can be concluded that the sodium channels of mammalian brain neurons have structures and functions similar to peripheral channels.

  16. Blockade of the voltage-dependent sodium current in isolated rat hippocampal neurons by tetrodotoxin and lidocaine. (United States)

    Kaneda, M; Oyama, Y; Ikemoto, Y; Akaike, N


    The effects of tetrodotoxin and lidocaine on the voltage-dependent sodium current (INa) were studied in the CA1 pyramidal neurons isolated acutely from rat hippocampus using a 'concentration-clamp' technique which combines the intracellular perfusion with a rapid external solution change within a few ms. Tetrodotoxin (TTX) exerted its inhibitory action in time- and dose-dependent manner on the peak amplitude of INa without any apparent effects on both the current activation and inactivation processes of the current. The time course for reaching a steady-state of the inhibitory action shortened with increasing TTX concentration, but the time course of recovery from the inhibition after washing out the toxin was quite the same at any concentrations used. Lidocaine also inhibited dose-dependently the INa, though with slightly accelerating both the activation and inactivation processes. The time courses for reaching the steady-state inhibition and the recovery from the inhibition were much shorter than those in the case of TTX. The results indicate that the voltage-dependent sodium channel of mammalian brain neuron is TTX-sensitive as well as that of peripheral neuron and that the mode of TTX inhibition on the INa is quite different from that of lidocaine.

  17. A high-stability scanning tunneling microscope achieved by an isolated tiny scanner with low voltage imaging capability (United States)

    Wang, Qi; Hou, Yubin; Wang, Junting; Lu, Qingyou


    We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d31 coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.

  18. High voltage research (breakdown strengths of gaseous and liquid insulators) and environmental effects of dielectric gases. Semiannual report, October 1, 1979-March 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Christophorou, L.G.; James, D.R.; Pai, R.Y.


    Topics covered include basic studies of gaseous dielectrics, direct current breakdown strengths of gases/mixtures, environmental effects studies and decomposition analyses, impulse studies, breakdown strengths of binary mixtures with concentric cylinder geometry, and a discussion of the experimental apparatus. (GHT)

  19. 断路器并联电容器现场高压介损测量研究%Field Measurement of High-voltage Dielectric Loss'for Breaker's Shunt Capacitor

    Institute of Scientific and Technical Information of China (English)

    陈伟; 夏谷林; 彭翔; 骆晓龙


    随着电压等级不断提高,常规10 kV介损测量方法应用于断路器并联电容器现场电容及介损测量存在着不足,笔者基于变频抗干扰技术原理,提出采取变频电源、外接标准电容器及串联电抗器谐振升压的高压介损测量方法.运用该方法对贺州、河池变电站500 kV断路器并联电容器进行了现场测量,测量结果表明了方法的可行性,并详细分析了测量结果与试验电压、湿度、RTV涂料、测量方式的关系及现场测量影响因素,对准确判断断路器并联电容器绝缘状态有着重要意义.%The conventional 10 kV dielectric loss measurement method for breaker's shunt capacitor has some shortages in field measurement with increasing voltage. A high-voltage dielectric loss measurement method based on the technology of anti-variable frequency interference is proposed by adopting variable frequency power source, external standard capacitor and series reactors for resonant boost. Field measurements of 500 kV breaker's shunt capacitors in Hezhou and Hechi transformer substations were conducted, and the results verified the proposed method. The relationships of measurement result with test voltage, humidity, RTV coating, and measurement mode, as well as the influencing factors in field measurement, are analyzed, which may benefit accurate judgement of insulation condition of a breaker's shunt capacitor.

  20. Phenolic acids isolated from the fungus Schizophyllum commune exert analgesic activity by inhibiting voltage-gated sodium channels. (United States)

    Yao, Hui-Min; Wang, Gan; Liu, Ya-Ping; Rong, Ming-Qiang; Shen, Chuan-Bin; Yan, Xiu-Wen; Luo, Xiao-Dong; Lai, Ren


    The present study was designed to search for compounds with analgesic activity from the Schizophyllum commune (SC), which is widely consumed as edible and medicinal mushroom world. Thin layer chromatography (TLC), tosilica gel column chromatography, sephadex LH 20, and reverse-phase high performance liquid chromatography (RP-HPLC) were used to isolate and purify compounds from SC. Structural analysis of the isolated compounds was based on nuclear magnetic resonance (NMR). The effects of these compounds on voltage-gated sodium (NaV) channels were evaluated using patch clamp. The analgesic activity of these compounds was tested in two types of mouse pain models induced by noxious chemicals. Five phenolic acids identified from SC extracts in the present study included vanillic acid, m-hydroxybenzoic acid, o-hydroxybenzeneacetic acid, 3-hydroxy-5-methybenzoic acid, and p-hydroxybenzoic acid. They inhibited the activity of both tetrodotoxin-resistant (TTX-r) and tetrodotoxin-sensitive (TTX-s) NaV channels. All the compounds showed low selectivity on NaV channel subtypes. After intraperitoneal injection, three compounds of these compounds exerted analgesic activity in mice. In conclusion, phenolic acids identified in SC demonstrated analgesic activity, facilitating the mechanistic studies of SC in the treatment of neurasthenia.

  1. Effect of etomidate on voltage-dependent potassium currents in rat isolated hippocampal pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    TAN Hong-yu; SUN Li-na; WANG Xiao-liang; YE Tie-hu


    Background Previous studies demonstrated general anesthetics affect potassium ion channels, which may be one of the mechanisms of general anesthesia. Because the effect of etomidate on potassium channels in rat hippocampus which is involved in memory function has not been studied, we investigated the effects of etomidate on both delayed rectifier potassium current (I_((K(DR))) and transient outward potassium current (I_((K(A))) in acutely dissociated rat hippocampal pyramidal neurons.Methods Single rat hippocampal pyramidal neurons from male Wistar rats of 7-10 days were acutely dissociated by enzymatic digestion and mechanical dispersion according to the methods of Kay and Wong with slight modification. Voltage-clamp recordings were performed in the whole-cell patch clamp configuration. Currents were recorded with a List EPC-10 amplifier and data were stored in a computer using Pulse 8.5. Student's paired two-tail t test was used for data analysis. Results At the concentration of 100 μmol/L, etomidate significantly inhibited I_(K(DR)) by 49.2% at +40 mV when depolarized from -110 mV (P 0.05). The IC_(50) value of etomidate for blocking I_(K(DR)) was calculated as 5.4 μmol/L, with a Hill slope of 2.45. At the presence of 10 μmol/L etomidate, the V_(1/2) of activation curve was shifted from (17.3±1.5) mV to (10.7±9.9) mV (n=8, P <0.05), the V_(1/2) of inactivation curve was shifted from (-18.3±2.2) mV to (-45.3±9.4) mV (n=8, P <0.05). Etomidate 10 μmol/L shifted both the activation curve and inactivation curve of I_(K(DR)) to negative potential, but mainly affected the inactivation kinetics.Conclusions Etomidate potently inhibited I_(K(DR)) but not I_(K(A)) in rat hippocampal pyramidal neurons. I_(K(DR)) was inhibited by etomidate in a concentration-dependent manner, while I_(K(A)) remained unaffected.

  2. Design of dielectric loss factor measurement with DSP for high voltage capacitive apparatus%基于DSP的高压容型电气设备介质损耗测量仪设计

    Institute of Scientific and Technical Information of China (English)



    针对电气设备易受电网频率波动和非整周期采样的影响,造成介质损耗因数tan δ测量精度和分辨率偏低的问题,提出一种基于DSP的高压电气设备介质损耗因数测量仪设计方案.将归一化工频电压信号和电流信号分别移相90°构成Hilbert变换对,再将两组复信号构造新的复三角信号模型实现对采样信号的去角频率处理.介绍了tanδ测量原理,给出了硬件各主要模块和系统软件实现方案.试验结果表明:该测量装置有效地解决了由于频率波动引起的非同步采样和非整周期截断问题,tan δ实际测量的绝对误差小于0.000 1,具有一定的实际推广价值.%Electrical equipment is vulnerable to fluctuations in the network frequency and non-integral period truncation conditions, and caused the dielectric loss factor measurement accuracy and resolution is low. An approach of dielectric loss factor measurement with DSP for high voltage capacitive apparatus is proposed. A Hilbert transform is build through moving voltage or current signals to 90 rad. The two signals are constructed a new complex triangle signal model. Introduced the dielectric loss factor measuring principle . The main modules and hardware system software scheme was given. Simulation and test results show that this algorithm reduced influence of non-synchronized sampling and non-integral period truncation caused by fluctuations in the network frequency. The absolute error of the dielectric loss factor is less than 0. 000 1. It has practical application value.

  3. Third harmonic generation in isolated all dielectric meta-atoms (Conference Presentation) (United States)

    Melik-Gaykazyan, Elizaveta V.; Shorokhov, Alexander S.; Shcherbakov, Maxim R.; Staude, Isabelle; Smirnova, Daria A.; Miroshnichenko, Andrey E.; Brener, Igal; Neshev, Dragomir N.; Fedyanin, Andrey A.; Kivshar, Yuri S.


    Two series of nanodisk arrays were designed. The first one was fabricated out of a silicon-on-insulator (SOI) wafer using electron-beam lithography and a reactive-ion etching process. The top layer of a SOI wafer is a 260-nm layer of monocrystalline (100)-cut silicon. We consider three square 400x400 μm2 arrays distinguished by the disk diameter values - 340, 345 and 360 nm, respectively; the period of the nanodisk ordering in the array amounted to 2.85 μm - this value allows for regarding the disks as isolated ones in terms of optical coupling. The nanodisk diameter choice specifies the magnetic dipolar (MD) resonance wavelength [1]. The second series of arrays was made of a 130-nm hydrogenated amorphous silicon (a-Si:H) film grown by plasma-enhanced chemical vapor deposition on a thin glass substrate. In order to study the nonlinear optical response of the nanodisks and verify the multipole resonances roles, we conducted third-harmonic generation (THG) spectroscopy measurements using a tunable (1.0-1.5 μm) optical parametric oscillator (200 fs pulses with the repetition rate of 76 MHz) pumped by a Ti:Sapphire laser. The laser beam waist diameter was set at 11 μm by an aspheric lens. The full thickness of both the SOI and glass wafers (˜500 μm each) was less than the waist depth. The resulting peak intensity reached the values of about 1 GW/cm2 in the sample plane. The laser beam polarization was linear as controlled by a Glan-Taylor laser prism. The transmitted and collimated THG signal was selected by a set of blue filters and detected by a photomultiplier tube connected with a lock-in amplifier. This signal was proven to be of TH origin by checking its cubic dependence on the pump power and by direct measurements of its spectrum. It was also verified that the THG beam was polarized parallel to the orientation of the pump beam polarization. It should be pointed out that the penetration depth of the THG into silicon does not exceed the nanodisk height. The

  4. High voltage engineering fundamentals

    CERN Document Server

    Kuffel, E; Hammond, P


    Provides a comprehensive treatment of high voltage engineering fundamentals at the introductory and intermediate levels. It covers: techniques used for generation and measurement of high direct, alternating and surge voltages for general application in industrial testing and selected special examples found in basic research; analytical and numerical calculation of electrostatic fields in simple practical insulation system; basic ionisation and decay processes in gases and breakdown mechanisms of gaseous, liquid and solid dielectrics; partial discharges and modern discharge detectors; and over

  5. High Voltage Test Apparatus for a Neutron EDM Experiment and Lower Limit on the Dielectric Strength of Liquid Helium at Large Volumes

    CERN Document Server

    Long, J C; Boissevain, J G; Clark, D J; Cooper, M D; Gómez, J J; Lamoreaux, S K; Mischke, R E; Penttila, S I


    A new search for a permanent electric dipole moment (EDM) of the neutron is underway using ultracold neutrons produced and held in a bath of superfluid helium. Attaining the target sensitivity requires maintaining an electric field of several tens of kilovolts per centimeter across the experimental cell, which is nominally 7.5 cm wide and will contain about 4 liters of superfluid. The electrical properties of liquid helium are expected to be sufficient to meet the design goals, but little is known about these properties for volumes and electrode spacings appropriate to the EDM experiment. Furthermore, direct application of the necessary voltages from an external source to the experimental test cell is impractical. An apparatus to amplify voltages in the liquid helium environment and to test the electrical properties of the liquid for large volumes and electrode spacings has been constructed. The device consists of a large-area parallel plate capacitor immersed in a 200 liter liquid helium dewar. Preliminary r...

  6. High temperature behavior of multi-region direct current current-voltage spectroscopy and relationship with shallow-trench-isolation-based high-voltage laterally diffused metal-oxide-semiconductor field-effect-transistors reliability (United States)

    He, Yandong; Zhang, Ganggang; Zhang, Xing


    With the process compatibility with the mainstream standard complementary metal-oxide-semiconductor (CMOS), shallow trench isolation (STI) based laterally diffused metal-oxide-semiconductor (LDMOS) devices have become popular for its better tradeoff between breakdown voltage and performance, especially for smart power applications. A multi-region direct current current-voltage (MR-DCIV) technique with spectroscopic features was demonstrated to map the interface state generation in the channel, accumulation and STI drift regions. High temperature behavior of MR-DCIV spectroscopy was analyzed and a physical model was verified. Degradation of STI-based LDMOS transistors under high temperature reverse bias (HTRB) stress is experimentally studied by MR-DCIV spectroscopy. The impact of interface state location on device electrical characteristics was investigated. Our results show that the major contribution to HTRB degradation, in term of the on-resistance degradation, was attributed to interface state generation under STI drift region.

  7. Application of Distribution Power Electronic Transformer for Medium Voltage

    Directory of Open Access Journals (Sweden)

    Prashant Kumar


    Full Text Available In   this   paper   a   distribution   power electronic transformer (DPET for feeding critical loads is presented. The PE based transformer is a multi-port converter that can connect to medium voltage levels on the primary side. Bidirectional power flow is provided to the each module. The presented structure consists of three stages: an input stage, an isolation stage, and an output stage.  The input current is sinusoidal, and it converts the high AC input voltage to low DC voltages. The isolated DC/DC converters are then connected to the DC links and provide galvanic isolation between the HV and LV sides. Finally, a three-phase inverter generates the AC output with the desired amplitude and frequency. The proposed DPET is extremely modular and can be extended for different voltage and power levels. It performs typical functions and has advantages such as power factor correction, elimination of voltage sag and swell, and reduction of voltage flicker in load side. Also in comparison to conventional transformers, it has lower weight, lower volume and eliminates necessity for toxic dielectric coolants the DPET performance is verified in MATLAB simulation.

  8. A simple method for reducing inevitable dielectric loss in high-permittivity dielectric elastomers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Mazurek, Piotr Stanislaw;


    Commercial viability of dielectric elastomers (DEs) is currently limited by a few obstacles, including high driving voltages (in the kV range). Driving voltage can be lowered by either decreasing the Young's modulus or increasing the dielectric permittivity of silicone elastomers, or a combinatio...... also decreased the dielectric losses of an elastomer containing dielectric permittivity-enhancing TiO2 fillers. Commercially available chloropropyl-functional silicone oil thus constitutes a facile method for improved silicone DEs, with very low dielectric losses....

  9. Functional interactions within the parahippocampal region revealed by voltage-sensitive dye imaging in the isolated guinea pig brain. (United States)

    Biella, Gerardo; Spaiardi, Paolo; Toselli, Mauro; de Curtis, Marco; Gnatkovsky, Vadym


    The massive transfer of information from the neocortex to the entorhinal cortex (and vice versa) is hindered by a powerful inhibitory control generated in the perirhinal cortex. In vivo and in vitro experiments performed in rodents and cats support this conclusion, further extended in the present study to the analysis of the interaction between the entorhinal cortex and other parahippocampal areas, such as the postrhinal and the retrosplenial cortices. The experiments were performed in the in vitro isolated guinea pig brain by a combined approach based on electrophysiological recordings and fast imaging of optical signals generated by voltage-sensitive dyes applied to the entire brain by arterial perfusion. Local stimuli delivered in different portions of the perirhinal, postrhinal, and retrosplenial cortex evoked local responses that did not propagate to the entorhinal cortex. Neither high- and low-frequency-patterned stimulation nor paired associative stimuli facilitated the propagation of activity to the entorhinal region. Similar stimulations performed during cholinergic neuromodulation with carbachol were also ineffective in overcoming the inhibitory network that controls propagation to the entorhinal cortex. The pharmacological inactivation of GABAergic transmission by local application of bicuculline (1 mM) in area 36 of the perirhinal cortex facilitated the longitudinal (rostrocaudal) propagation of activity into the perirhinal/postrhinal cortices but did not cause propagation into the entorhinal cortex. Bicuculline injection in both area 35 and medial entorhinal cortex released the inhibitory control and allowed the propagation of the neural activity to the entorhinal cortex. These results demonstrate that, as for the perirhinal-entorhinal reciprocal interactions, also the connections between the postrhinal/retrosplenial cortices and the entorhinal region are subject to a powerful inhibitory control.

  10. Isolated DC-DC Converter for Bidirectional Power Flow Controlling with Soft-Switching Feature and High Step-Up/Down Voltage Conversion

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen


    Full Text Available In this paper, a novel isolated bidirectional DC-DC converter is proposed, which is able to accomplish high step-up/down voltage conversion. Therefore, it is suitable for hybrid electric vehicle, fuel cell vehicle, energy backup system, and grid-system applications. The proposed converter incorporates a coupled inductor to behave forward-and-flyback energy conversion for high voltage ratio and provide galvanic isolation. The energy stored in the leakage inductor of the coupled inductor can be recycled without the use of additional snubber mechanism or clamped circuit. No matter in step-up or step-down mode, all power switches can operate with soft switching. Moreover, there is a inherit feature that metal–oxide–semiconductor field-effect transistors (MOSFETs with smaller on-state resistance can be adopted because of lower voltage endurance at primary side. Operation principle, voltage ratio derivation, and inductor design are thoroughly described in this paper. In addition, a 1-kW prototype is implemented to validate the feasibility and correctness of the converter. Experimental results indicate that the peak efficiencies in step-up and step-down modes can be up to 95.4% and 93.6%, respectively.

  11. 高压隔离开关带电检修分析%Analysis of High-Voltage Isolator Live Working

    Institute of Scientific and Technical Information of China (English)

    王灿飞; 李以然; 王军慧; 王妙松; 胡虓祥


    针对户外高压隔离开关在检修中存在的故障多发、停电检修困难等问题,分析了高压隔离开关的检修现状及故障多发原因。结合高压隔离开关带电检修的实际应用事例,指出带电检修的几个关键问题,并提出了相应对策,提高了设备运行和电网供电的可靠性。%Aiming at the problems such that failures happen frequently and it’s difficult to repair with outage during the process of overhauling high-voltage isolators in open air, this paper analyzed the live working of high-voltage isolators and the reasons of frequent failures. Combined with the practical application examples of the live working of high-voltage isolators, this paper pointed out several key problems of the live working, raising the corresponding countermeasures, which improves the reliability of equipment operation and grid power supply.

  12. Development of a dielectric ceramic based on diatomite-titania part two: dielectric properties characterization

    Directory of Open Access Journals (Sweden)

    Medeiros Jamilson Pinto


    Full Text Available Dielectric properties of sintered diatomite-titania ceramics are presented. Specific capacitance, dissipation factor, quality factor and dielectric constant were determined as a function of sintering temperature, titania content and frequency; the temperature coefficient of capacitance was measured as a function of frequency. Besides leakage current, the dependence of the insulation resistance and the dielectric strength on the applied dc voltage were studied. The results show that diatomite-titania compositions can be used as an alternative dielectric.

  13. Breakdown voltage of discrete capacitors under single-pulse conditions (United States)

    Domingos, H.; Scaturro, J.; Hayes, L.


    For electrostatic capacitors the breakdown voltage is inherently related to the properties of the dielectric, with the important parameters being the dielectric field strength which is related to the dielectric constant and the dielectric thickness. These are not necessarily related to the capacitance value and the rated voltage, but generally the larger values of capacitance have lower breakdown voltages. Foil and wet slug electrolytics can withstand conduction currents pulses without apparent damage (in either direction for foil types). For solid tantalums, damage occurs whenever the capacitor charges to the forming voltage.

  14. Investigations on Substrate Temperature-Induced Growth Modes of Organic Semiconductors at Dielectric/semiconductor Interface and Their Correlation with Threshold Voltage Stability in Organic Field-Effect Transistors. (United States)

    Padma, Narayanan; Maheshwari, Priya; Bhattacharya, Debarati; Tokas, Raj B; Sen, Shashwati; Honda, Yoshihide; Basu, Saibal; Pujari, Pradeep Kumar; Rao, T V Chandrasekhar


    Influence of substrate temperature on growth modes of copper phthalocyanine (CuPc) thin films at the dielectric/semiconductor interface in organic field effect transistors (OFETs) is investigated. Atomic force microscopy (AFM) imaging at the interface reveals a change from 'layer+island' to "island" growth mode with increasing substrate temperatures, further confirmed by probing the buried interfaces using X-ray reflectivity (XRR) and positron annihilation spectroscopic (PAS) techniques. PAS depth profiling provides insight into the details of molecular ordering while positron lifetime measurements reveal the difference in packing modes of CuPc molecules at the interface. XRR measurements show systematic increase in interface width and electron density correlating well with the change from layer + island to coalesced huge 3D islands at higher substrate temperatures. Study demonstrates the usefulness of XRR and PAS techniques to study growth modes at buried interfaces and reveals the influence of growth modes of semiconductor at the interface on hole and electron trap concentrations individually, thereby affecting hysteresis and threshold voltage stability. Minimum hole trapping is correlated to near layer by layer formation close to the interface at 100 °C and maximum to the island formation with large voids between the grains at 225 °C.

  15. A New Approach to High Efficincy in Isolated Boost Converters for High-Power Low-Voltage Fuel Cell Apllications

    DEFF Research Database (Denmark)

    Nymand, Morten; Andersen, Michael A. E.


    by the use of power MOSFETs fully rated for repetitive avalanche. Voltage rating of primary switches can now be reduced, significantly reducing switch on-state losses. Finally, silicon carbide rectifying diodes allow fast diode turn-off, further reducing losses. Test results from a 1.5 kW full-bridge boost...

  16. Single-channel properties of the reconstituted voltage-regulated Na channel isolated from the electroplax of Electrophorus electricus. (United States)

    Rosenberg, R L; Tomiko, S A; Agnew, W S


    The tetrodotoxin-binding protein purified from electroplax of Electrophorus electricus has been reincorporated into multilamellar vesicles that were used for patch recording. When excised patches of these reconstituted membranes were voltage clamped in the absence of neurotoxins, voltage-dependent single-channel currents were recorded. These displayed properties qualitatively and quantitatively similar to those reported for Na channels from nerve and muscle cells, including uniform single-channel conductances of the appropriate magnitude (approximately equal to 11 pS in 95 mM Na+), mean open times of approximately equal to 1.9 msec, and 7-fold selectively for Na+ over K+. Currents averaged from many depolarizations showed initial voltage-dependent activation and subsequent inactivation. In the presence of batrachotoxin, channels were observed with markedly different properties, including conductances of 20-25 pS (95 mM Na+), mean open times of approximately equal to 28 msec, and no indication of inactivation. Collectively, these findings indicate that the tetrodotoxin-binding protein of electroplax is a voltage-regulated sodium channel. PMID:6089214

  17. Artificial Dielectric Shields for Integrated Transmission Lines

    NARCIS (Netherlands)

    Ma, Y.; Rejaei, B.; Zhuang, Y.


    We present a novel shielding method for on-chip transmission lines built on conductive silicon substrates. The shield consists of an artificial dielectric with a very high in-plane dielectric constant, built from two patterned metal layers isolated by a very thin dielectric film. Inserted below an i

  18. Composite Dielectric Materials for Electrical Switching

    Energy Technology Data Exchange (ETDEWEB)

    Modine, F.A.


    Composites that consist of a dielectric host containing a particulate conductor as a second phase are of interest for electrical switching applications. Such composites are "smart" materials that can function as either voltage or current limiters, and the difference in fimction depends largely upon whether the dielectric is filled to below or above the percolation threshold. It also is possible to combine current and voltage limiting in a single composite to make a "super-smart" material.

  19. Charging a Battery-Powered Device with a Fiber-Optically Connected Photonic Power System for Achieving High-Voltage Isolation

    Energy Technology Data Exchange (ETDEWEB)

    Lizon, David C [Los Alamos National Laboratory; Gioria, Jack G [Los Alamos National Laboratory; Dale, Gregory E [Los Alamos National Laboratory; Snyder, Hans R [Los Alamos National Laboratory


    This paper describes the development and testing of a system to provide isolated power to the cathode-subsystem electronics of an x-ray tube. These components are located at the cathode potential of several hundred kilovolts, requiring a supply of power isolated from this high voltage. In this design a fiber-optically connected photonic power system (PPS) is used to recharge a lithium-ion battery pack, which will subsequently supply power to the cathode-subsystem electronics. The suitability of the commercially available JDSU PPS for this application is evaluated. The output of the ppe converter is characterized. The technical aspects of its use for charging a variety of Li-Ion batteries are discussed. Battery charge protection requirements and safety concerns are also addressed.

  20. Super soft silicone elastomers with high dielectric permittivity

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Hvilsted, Søren;


    Dielectric elastomers (DEs) have many favourable properties. The obstacle of high driving voltages, however, limits the commercial viability of the technology at present. Driving voltage can be lowered by decreasing the Young’s modulus and increasing the dielectric permittivity of silicone elasto...

  1. Dielectric Metamaterials (United States)


    Final Report  29 May 2015 Dielectric Metamaterials SRI Project P21340 ONR Contract N00014-12-1-0722 Prepared by: Srini Krishnamurthy...2 2. Theory of Metamaterials ....................................................................................................... 2 2.1...accurately assess the impact of various forms of disorder on metamaterials (MMs) (both dielectric and metal inclusions); and (5) identify designs

  2. Novel high dielectric constant hybrid elastomers based on glycerol-insilicone emulsions

    DEFF Research Database (Denmark)

    Mazurek, Piotr Stanislaw; Skov, Anne Ladegaard


    distributed within PDMS in shape of discrete droplets thus acting as a high dielectric constant filler efficiently enhancing the dielectric constant of the composites. Low- and high-voltage dielectric spectroscopy measurements were conducted in order to verify applicability of the composites as dielectric...

  3. Transient voltage-dependent potassium currents are reduced in NTS neurons isolated from renal wrap hypertensive rats. (United States)

    Belugin, Sergei; Mifflin, Steve


    Whole cell patch-clamp measurements were made in neurons enzymatically dispersed from the nucleus of the solitary tract (NTS) to determine if alterations occur in voltage-dependent potassium channels from rats made hypertensive (HT) by unilateral nephrectomy/renal wrap for 4 wk. Some rats had the fluorescent tracer DiA applied to the aortic nerve before the experiment to identify NTS neurons receiving monosynaptic baroreceptor afferent inputs. Mean arterial pressure (MAP) was greater in 4-wk HT (165 +/- 5 mmHg, n = 26, P NTS neurons from NT and HT rats. At activation voltages from -10 to +10 mV, TOCs were significantly less in HT neurons compared with those observed in NT neurons (P NTS neurons from NT and HT rats and was not different comparing neurons from NT and HT rats. However, examination of the subset of NTS neurons exhibiting somatic DiA fluorescence revealed that DiA-labeled neurons from HT rats had a significantly shorter duration delayed excitation (n = 8 cells, P = 0.022) than DiA-labeled neurons from NT rats (n = 7 cells). Neurons with delayed excitation from HT rats had a significantly broader first action potential (AP) and a slower maximal downstroke velocity of repolarization compared with NT neurons with delayed excitation (P = 0.016 and P = 0.014, respectively). The number of APs in the first 200 ms of a sustained depolarization was greater in HT than NT neurons (P = 0.012). These results suggest that HT of 4-wk duration reduces TOCs in NTS neurons, and this contributes to reduced delayed excitation and increased AP responses to depolarizing inputs. Such changes could alter baroreflex function in hypertension.

  4. Low Voltage Power Supply Incorporating Ceramic Transformer

    CERN Document Server

    Imori, M


    A low voltage power supply provides the regulated output voltage of 1 V from the supply voltage around 48 V. The low voltage power supply incorporates a ceramic transformer which utilizes piezoelectric effect to convert voltage. The ceramic transformer isolates the secondary from the primary, thus providing the ground isolation between the supply and the output voltages. The ceramic transformer takes the place of the conventional magnetic transformer. The ceramic transformer is constructed from a ceramic bar and does not include any magnetic material. So the low voltage power supply can operate under a magnetic field. The output voltage is stabilized by feedback. A feedback loop consists of an error amplifier, a voltage controlled oscillator and a driver circuit. The amplitude ratio of the transformer has dependence on the frequency, which is utilized to stabilize the output voltage. The low voltage power supply is investigated on the analogy of the high voltage power supply similarly incorporating the cerami...

  5. High voltage and electrical insulation engineering

    CERN Document Server

    Arora, Ravindra


    "The book is written for students as well as for teachers and researchers in the field of High Voltage and Insulation Engineering. It is based on the advance level courses conducted at TU Dresden, Germany and Indian Institute of Technology Kanpur, India. The book has a novel approach describing the fundamental concept of field dependent behavior of dielectrics subjected to high voltage. There is no other book in the field of high voltage engineering following this new approach in describing the behavior of dielectrics. The contents begin with the description of fundamental terminology in the subject of high voltage engineering. It is followed by the classification of electric fields and the techniques of field estimation. Performance of gaseous, liquid and solid dielectrics under different field conditions is described in the subsequent chapters. Separate chapters on vacuum as insulation and the lightning phenomenon are included"--

  6. Dielectric breakdown of cell membranes. (United States)

    Zimmermann, U; Pilwat, G; Riemann, F


    With human and bovine red blood cells and Escherichia coli B, dielectric breakdown of cell membranes could be demonstrated using a Coulter Counter (AEG-Telefunken, Ulm, West Germany) with a hydrodynamic focusing orifice. In making measurements of the size distributions of red blood cells and bacteria versus increasing electric field strength and plotting the pulse heights versus the electric field strength, a sharp bend in the otherwise linear curve is observed due to the dielectric breakdown of the membranes. Solution of Laplace's equation for the electric field generated yields a value of about 1.6 V for the membrane potential at which dielectric breakdown occurs with modal volumes of red blood cells and bacteria. The same value is also calculated for red blood cells by applying the capacitor spring model of Crowley (1973. Biophys. J. 13:711). The corresponding electric field strength generated in the membrane at breakdown is of the order of 4 . 10(6) V/cm and, therefore, comparable with the breakdown voltages for bilayers of most oils. The critical detector voltage for breakdown depends on the volume of the cells. The volume-dependence predicted by Laplace theory with the assumption that the potential generated across the membrane is independent of volume, could be verified experimentally. Due to dielectric breakdown the red blood cells lose hemoglobin completely. This phenomenon was used to study dielectric breakdown of red blood cells in a homogeneous electric field between two flat platinum electrodes. The electric field was applied by discharging a high voltage storage capacitor via a spark gap. The calculated value of the membrane potential generated to produce dielectric breakdown in the homogeneous field is of the same order as found by means of the Coulter Counter. This indicates that mechanical rupture of the red blood cells by the hydrodynamic forces in the orifice of the Coulter Counter could also be excluded as a hemolysing mechanism. The detector

  7. Dielectric and photo-dielectric properties of TlGaSeS crystals

    Indian Academy of Sciences (India)

    A F Qasrawi; Samah F Abu-Zaid; Salam A Ghanameh; N M Gasanly


    The room temperature, dark and photo-dielectric properties of the novel crystals TlGaSeS are investigated in the frequency, intensity and biasing voltage having ranges of ~ 1–120 MHz, 14–40 klux and 0–1 V, respectively. The crystals are observed to exhibit a dark high frequency effective dielectric constant value of ∼ 10.65 × 103 with a quality factor of ∼ 8.84 × 104 at ∼ 120 MHz. The dielectric spectra showed sharp resonance–antiresonance peaks in the frequency range of ∼ 25–250 kHz. When photoexcited, pronounced increase in the dielectric constant and in the quality factor values with increasing illumination intensity are observed. Signal amplification up to ∼ 33% with improved signal quality up to ∼ 29% is attainable via photoexcitation. On the other hand, the illuminated capacitance–voltage characteristics of the crystals reflected a downward shift in the voltage biasing and in the built-in voltage of the device that is associated with increase in the uncompensated carrier density. The increase in the dielectric constant with increasing illumination intensity is ascribed to the decrease in the crystal's resistance as a result of increased free carrier density. The light sensitivity of the crystals, the improved dielectric properties and the lower biasing voltage obtained via photoexcitation and the well-enhanced signal quality factor of the crystals make them promising candidates for optical communication systems.

  8. Dual-Input Soft-Switched DC-DC Converter with Isolated Current-Fed Half-Bridge and Voltage-Fed Full-Bridge for Fuel Cell or Photovoltaic Systems

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.


    This paper introduces a new zero-voltage-switching (ZVS) isolated DC-DC converter with two input ports which can be utilized in hybrid energy systems, for instance, in a fuel cell and super-capacitor system. By fully using two high frequency transformers, the proposed converter can effectively...

  9. High permittivity gate dielectric materials

    CERN Document Server


    "The book comprehensively covers all the current and the emerging areas of the physics and the technology of high permittivity gate dielectric materials, including, topics such as MOSFET basics and characteristics, hafnium-based gate dielectric materials, Hf-based gate dielectric processing, metal gate electrodes, flat-band and threshold voltage tuning, channel mobility, high-k gate stack degradation and reliability, lanthanide-based high-k gate stack materials, ternary hafnia and lanthania based high-k gate stack films, crystalline high-k oxides, high mobility substrates, and parameter extraction. Each chapter begins with the basics necessary for understanding the topic, followed by a comprehensive review of the literature, and ultimately graduating to the current status of the technology and our scientific understanding and the future prospects."

  10. End moldings for cable dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Roose, L.D.


    End moldings for high-voltage cables are described wherein the dielectric insulator of the cable is heated and molded to conform to a desired shape. As a consequence, high quality substantially bubble- free cable connectors suitable for mating to premanufactured fittings are made. Disclosed are a method for making the cable connectors either in the field or in a factory, molds suitable for use with the method, and the molded cable connectors, themselves.

  11. Low-voltage large-current ion gel gated polymer transistors fabricated by a "cut and bond" process. (United States)

    Shao, Xianyi; Bao, Bei; Zhao, Jiaqing; Tang, Wei; Wang, Shun; Guo, Xiaojun


    A "cut and bond" process using a commercial die bonder was developed for fabricating ion gel gated organic thin-film transistors (OTFTs). It addresses the issues of damaging or contaminating the channel layer when depositing the ion gel layer on top in conventional fabrication processes. The formed isolated dielectric regions can help to eliminate possible lateral electric field coupling through the dielectric layer when several devices are integrated to construct functional circuits. The fabricated OTFTs provide mA-level ON current, and an ON/OFF current ratio higher than 10(5) with the gate swing voltage of less than 3 V. With the developed process, the ion gel OTFTs are integrated with inorganic light emitting diodes (LEDs) of different colors on plastic substrate using the same die bonder, and the light emission of the LEDs can be modulated in a wide range from dark to high brightness with change of the gate voltage less than 3 V.

  12. Decomposing Nitrous Oxide Thruster using Dielectric Barrier Discharge Project (United States)

    National Aeronautics and Space Administration — The University of Maryland is proposing to use a dielectric barrier discharge (DBD) as a means to dissociate N2O. DBD uses alternating high voltage differences...

  13. A study on threshold voltage stability of low operating voltage organic thin-film transistors (United States)

    Padma, N.; Sen, Shaswati; Sawant, Shilpa N.; Tokas, R.


    A low operating voltage (<2 V) organic field-effect transistor (OFET) using phenylhexyltrichlorosilane (PTS) self-assembled monolayer (SAM) dielectric and copper phthalocyanine (CuPc) as semiconductor with improved mobility (0.035 cm2 V-1 s-1) and threshold voltage stability was demonstrated. This device showed better performance when compared to an OFET with octyltrichlorosilane (OTS-8) SAM dielectric. The improved mobility was attributed to the 2D growth mode of CuPc on PTS SAM because of surface energy matching between the two, whereas CuPc film on OTS-8 showed a 3D growth mode with larger grain boundary density. The higher threshold voltage stability of OFETs on PTS SAM was attributed to the efficient coverage and screening of trap centres at dielectric/semiconductor interface due to stronger intermolecular linking and formation of closely packed surface by the bulky phenyl end groups. Decrease in grain boundaries offered by 2D growth of CuPc for electron and hole trapping was also found to be another reason for improved threshold voltage stability. The results indicated that the nature of the end group of SAM dielectric, surface chemistry of dielectric and initial growth mode of semiconductors are all responsible for improvement in threshold voltage stability and enhanced performance of OFET.

  14. 一种光纤隔离式直流信号传输装置的设计%A design of high voltage DC signal fiber isolation-transmission device

    Institute of Scientific and Technical Information of China (English)

    苑舜; 刘红江; 蔡志远


    In high-voltage fields, high-voltage side inspection equipment (such as CT, PT) or the output signal of the sensor needs to be transmitted to the low-voltage side, the fiber isolation-transmission device not only can complete the transmission of the signal and achieve electrical isolation, but also has a strong ability to re-sist electromagnetic interference. A set of fiber isolation- transmission device for high-voltage DC measure-ment signal is designed by using the voltage frequency conversion (VFC) chip LM331 and photoelectric con-verter HFBR14XX. The circuit also is given. The V-F converter circuit is simulated, and the analysis shows that its error is 0.01 V.%在高电压领域中,高压侧检测设备(如PT,CT)或传感器的输出信号需要传输到低压侧,光纤隔离式信号传输装置不仅能完成信号的传输,还能实现高低压的电气隔离,同时也具有很强的抗电磁干扰能力。利用电压-频率(V-F)转换芯片LM331和HFBR14XX系列光电器件设计出一套适合高电压直流测量信号的光纤隔离传输装置,并给出了具体的电路原理图。对其中的V-F转换电路进行了仿真,分析表明,其误差为0.01 V。

  15. Virtual gap dielectric wall accelerator (United States)

    Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A


    A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

  16. Non-isolated DC-AC converter with high voltage gain for autonomous systems of electric power; Conversor CC-CA nao isolado com alto ganho de tensao para aplicacao em sistemas autonomos de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, George Cajazeiras [Centro Federal de Educacao Tecnologica do Ceara (CEFET/CE), Fortaleza, CE (Brazil); Torrico-Bascope, Rene P. [Universidade Federal do Ceara (PPGEE/UFC), Fortaleza, CE (Brazil). Programa de Pos Graduacao em Engenharia Eletrica; Borges Neto, Manuel Rangel [Centro Federal de Educacao Tecnologica de Petrolina (CEFET-PET), PE (Brazil)


    A non-isolated DC-AC converter with high voltage gain with two output sinusoidal voltage - 110 V and 220 V - and frequency 60 Hz for application in autonomous systems of electric power is proposed in this work. This topology consists of a boost converter with high voltage gain, based on three-state switching cell combined with a double half bridge inverter. This configuration type the size and the cost are reduced and the efficiency is gotten better, due to the reduced number of switches. The converters that compose this topology operate with high frequency, reducing the volume of the magnetic materials. can be mention as important characteristics: the voltage stress across the switches of the boost converter are low, due they be naturally clamped by one output filter capacitor, which allows the utilization of switches with lower conduction resistances, and the waveforms of the output voltage of the double half bridge inverter supplies for the load it is sinusoidal and it possesses low harmonic content. (author)

  17. Dielectric capacitors with three-dimensional nanoscale interdigital electrodes for energy storage. (United States)

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


    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.

  18. Marine High-voltage Motor Winding Dielectric Loss Angle Correction Algorithm%海洋高压电机绕组中介质损耗角的校正算法

    Institute of Scientific and Technical Information of China (English)

    李阳勤; 刘敬彪; 蔡文郁; 霍洪强


    This paper describes a marine high-pressure motor winding dielectric loss angle correction algorithm and outlines China's marine expedition equipments and the necessity of preventing insulation accidents in entire power system .Also it introduces the dielectric loss angle calculation process based on the harmonic analysis , and analyzes the error caused by the harmonic algorithm .Then proposed a correction method combing window leak and fence effect of disclosure—the use of Hamming window weighting function and the fast Fourier transform correction method , which corrects the frequency , amplitude and phase angle respectively .The value of the dielectric loss get from improved harmonic analysis method by the frequency fluctuation is very small , measured in the field .%介绍了一种海洋高压电机绕组中介质损耗角的校正算法。详述了基于谐波分析法的介质损耗角的计算过程,通过分析谐波算法带来的误差原因,根据误差主要原因窗泄露以及栅栏效应提出了将二者合二为一的校正方法,使用汉明窗加权函数和快速傅里叶变换的校正方法,分别对频率、幅值和相位角进行校正改进,改进的谐波分析法得出的介质损耗值受频率变化波动非常小,在现场测量中得到了充分的验证。

  19. Comparison of the dielectric electroactive polymer generator energy harvesting cycles

    DEFF Research Database (Denmark)

    Dimopoulos, Emmanouil; Trintis, Ionut; Munk-Nielsen, Stig


    The Dielectric ElectroActive Polymer (DEAP) generator energy harvesting cycles have been in the spotlight of the scientific interest for the past few years. Indeed, several articles have demonstrated thorough and comprehensive comparisons of the generator fundamental energy harvesting cycles......, namely Constant Charge (CC), Constant Voltage (CV) and Constant E-field (CE), based on averaged theoretical models. Yet, it has not been possible until present to validate the outcome of those comparisons via respective experimental results. In this paper, all three primary energy harvesting cycles...... are experimentally compared, based upon the coupling of a DEAP generator with a bidirectional non-isolated power electronic converter, by means of energy gain, energy harvesting efficiency and energy conversion efficiency....

  20. Voltage mapping for delineating inexcitable dense scar in patients undergoing atrial fibrillation ablation: a new end point for enhancing pulmonary vein isolation. (United States)

    Squara, Fabien; Frankel, David S; Schaller, Robert; Kapa, Suraj; Chik, William W; Callans, David J; Marchlinski, Francis E; Dixit, Sanjay


    Characterization of left atrial scar using bipolar voltage (BiV) mapping is not well defined. We have previously shown that the BiV range of 0.2-0.45 mV can identify chronic scar from prior pulmonary vein isolation (PVI). This study sought to determine a BiV range that can identify atrial inexcitable dense scar (IDS) in patients acutely and chronically after PVI. Thirty consecutive patients undergoing first time (n = 15) or redo (n = 15) PVI were included. A left atrial shell was created using electroanatomic mapping, and IDS was defined by inability to capture at an output of 10 mA and a pulse width of 2 ms in sinus rhythm, circumferentially at the edge of PVI-related scar (≤5 mm). At each pacing site, BiV amplitude and atrial capture were recorded. Overall, 837 pacing sites were assessed. BiV predicted IDS (receiver operating characteristic curve area 0.93 for first time PVI and 0.90 for redo PVI). In first time PVI, the best BiV value to predict IDS was 0.45 mV for the left pulmonary vein-left atrial appendage (LAA-LPV) ridge (sensitivity 0.98; specificity 1.0) and 0.2 mV for other localizations (sensitivity 0.91; specificity 0.86). In redo PVI, the best BiV value to predict IDS was 0.2 mV for the LAA-LPV ridge (sensitivity 0.77; specificity 1.0) and 0.15 mV for other localizations (sensitivity 0.81; specificity 0.82). BiV reproducibly identifies acute and chronic IDS using a cutoff value of 0.2 mV (0.45 mV for the LAA-LPV ridge) in patients undergoing first time PVI and 0.15 mV (0.2 mV for the LAA-LPV ridge) in patients undergoing redo PVI. IDS thus identified may be a rigorous tool for validating PVI. Published by Elsevier Inc.

  1. Nanostructure multilayer dielectric materials for capacitors and insulators (United States)

    Barbee, Jr., Troy W.; Johnson, Gary W.


    A capacitor is formed of at least two metal conductors having a multilayer dielectric and opposite dielectric-conductor interface layers in between. The multilayer dielectric includes many alternating layers of amorphous zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3). The dielectric-conductor interface layers are engineered for increased voltage breakdown and extended service life. The local interfacial work function is increased to reduce charge injection and thus increase breakdown voltage. Proper material choices can prevent electrochemical reactions and diffusion between the conductor and dielectric. Physical vapor deposition is used to deposit the zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3) in alternating layers to form a nano-laminate.

  2. Dependence of Pentacene Crystal Growth on Dielectric Roughness for Fabrication of Flexible Field-Effect Transistors

    Energy Technology Data Exchange (ETDEWEB)

    Yang, H.; Yang, C; Kim, S; Jang, M; Park, C


    The dependence of pentacene nanostructures on gate dielectric surfaces were investigated for flexible organic field-effect transistor (OFET) applications. Two bilayer types of polymer/aluminum oxide (Al{sub 2}O{sub 3}) gate dielectrics were fabricated on commercial Al foils laminated onto a polymer back plate. Some Al foils were directly used as gate electrodes, and others were smoothly polished by an electrolytic etching. These Al surfaces were then anodized and coated with poly({alpha}-methyl styrene) (PAMS). For PAMS/Al{sub 2}O{sub 3} dielectrics onto etched Al foils, surface roughness up to 1 nm could be reached, although isolated dimples with a lateral diameter of several micrometers were still present. On PAMS/Al{sub 2}O{sub 3} dielectrics (surface roughness >40 nm) containing mechanical grooves of Al foil, average hole mobility ({mu}FET) of 50 nm thick pentacene-FETs under the low operating voltages (|V| < 6 V) was {approx}0.15 cm{sup 2} V{sup -1} s{sup -1}. In contrast, pentacene-FETs employing the etched Al gates exhibited {mu}FET of 0.39 cm{sup 2} V{sup -1} s{sup -1}, which was comparable to that of reference samples with PAMS/Al{sub 2}O{sub 3} dielectrics onto flat sputtered Al gates. Conducting-probe atomic force microscopy and two-dimensional X-ray diffraction of pentacene films with various thicknesses revealed different out-of-plane and in-plane crystal orderings of pentacene, depending on the surface roughness of the gate dielectrics.

  3. Dielectric metasurfaces (United States)

    Valentine, Jason

    While plasmonics metasurfaces have seen much development over the past several years, they still face throughput limitations due to ohmic losses. On the other hand, dielectric resonators and associated metasurfaces can eliminate the issue of ohmic loss while still providing the freedom to engineer the optical properties of the composite. In this talk, I will present our recent efforts to harness this freedom using metasurfaces formed from silicon and fabricated using CMOS-compatible techniques. Operating in the telecommunications band, I will discuss how we have used this platform to realize a number of novel functionalities including wavefront control, near-perfect reflection, and high quality factor resonances. In many cases the optical performance of these silicon-based metasurfaces can surpass their plasmonic counterparts. Furthermore, for some cases the surfaces are more amenable to large-area fabrication techniques.

  4. 2.3-MW Medium-Voltage, Three-Level Wind Energy Inverter Applying a Unique Bus Structure and 4.5-kV Si/SiC Hybrid Isolated Power Modules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Erdman, W.; Keller, J.; Grider, D.; VanBrunt, E.


    A high-efficiency, 2.3-MW, medium-voltage, three-level inverter utilizing 4.5-kV Si/SiC (silicon carbide) hybrid modules for wind energy applications is discussed. The inverter addresses recent trends in siting the inverter within the base of multimegawatt turbine towers. A simplified split, three-layer laminated bus structure that maintains low parasitic inductances is introduced along with a low-voltage, high-current test method for determining these inductances. Feed-thru bushings, edge fill methods, and other design features of the laminated bus structure provide voltage isolation that is consistent with the 10.4-kV module isolation levels. Inverter efficiency improvement is a result of the (essential) elimination of the reverse recovery charge present in 4.5-kV Si PIN diodes, which can produce a significant reduction in diode turn-off losses as well as insulated-gate bipolar transistor (IGBT) turn-on losses. The hybrid modules are supplied in industry-standard 140 mm x 130 mm and 190 mm x 130 mm packages to demonstrate direct module substitution into existing inverter designs. A focus on laminated bus/capacitor-bank/module subassembly level switching performance is presented.

  5. 隔离型DC/DC在高压电压电流源设计中的应用%Application of isolated DC/DC converter in high level voltage and current source design

    Institute of Scientific and Technical Information of China (English)

    黄弋; 周菁


    由于隔离型DC/DC的安全性、隔离性等特征,该类器件广泛应用于多个电子、工业领域,本文主要介绍了隔离型DC/DC在高压电压电流源中的应用。本文将隔离型双输出DC/DC引入设计,利用DC/DC的隔离特性,将电压电流源的次级输出作为DC/DC器件参考地,将DC/DC器件的两路输出电压作为相关运算放大器的电源电压。常规高压电压电流源设计中需要大量采用高压运算放大器,采用此方案可使用较少的高压运算放大器及更低的成本实现相同功能,同时降低高压电源对PCB电路板上信号的影响。通过实际测量,文中方案输出稳定、精度高,满足设计与使用要求。文中用功能图纸对此类应用进行了详细说明。%Because of the Characteristics of safety and reliability, isolated DC/DC converter is widely used in many fields, such as electronic field and industry field. This paper describes the application of isolated DC/DC converter in ATE voltage and current source designing. The voltage and current source circuit are mainly realized by Operational amplifiers. When isolated DC/DC converter is used in the design, we can use less Operational amplifiers and cost less to realize the same function. In the project, the two voltage outputs of isolated DC/DC converter are used as power supply of Operational amplifiers, and the secondary output of voltage and current source is used as reference ground. It is effective to reduce system noise of high voltage power supply and to make signal quality on PCB getting better. It was confirmed that the system we discussed in this paper meet the requirements of reliability and precision through the measurement result. The details of the schematic are also describes in the paper

  6. Fabrication and characterization of nanometer thin films for low-voltage DEAs



    Nanometer-thin films are the essential components of a low-voltage dielectric elastomer actuator (DEA). Comprising of two electrodes sandwiching a dielectric elastomeric material DEAs have evoked versatile materials research. Before choosing the materials used to manufacture low-voltage DEAs one should carefully consider the targeted application. This project aims at finding new techniques to realize nanometer-thin films to obtain low-voltage DEAs with possible future application as artificia...

  7. Radiatively heated high voltage pyroelectric crystal pulser

    Energy Technology Data Exchange (ETDEWEB)

    Antolak, A.J., E-mail: [Sandia National Laboratories, Livermore, CA 94550 (United States); Chen, A.X. [Sandia National Laboratories, Livermore, CA 94550 (United States); Leung, K.-N. [Sandia National Laboratories, Livermore, CA 94550 (United States); Nuclear Engineering Department, University of California, Berkeley (United States); Morse, D.H.; Raber, T.N. [Sandia National Laboratories, Livermore, CA 94550 (United States)


    Thin lithium tantalate pyroelectric crystals in a multi-stage pulser were heated by quartz lamps during their charging phase to generate high voltage pulses. The charging voltage was determined empirically based on the measured breakdown voltage in air and verified by the induced breakdown voltage of an external high voltage power supply. A four-stage pyroelectric crystal device generated pulse discharges of up to 86 kV using both quartz lamps (radiative) and thermoelectric (conductive) heating. Approximately 50 mJ of electrical energy was harvested from the crystals when radiatively heated in air, and up to 720 mJ was produced when the crystals were submerged in a dielectric fluid. It is anticipated that joule-level pulse discharges could be obtained by employing additional stages and optimizing the heating configuration.


    Energy Technology Data Exchange (ETDEWEB)

    Caporaso, G J; Chen, Y; Sampayan, S; Akana, G; Anaya, R; Blackfield, D; Carroll, J; Cook, E; Falabella, S; Guethlein, G; Harris, J; Hawkins, S; Hickman, B; Holmes, C; Horner, A; Nelson, S; Paul, A; Pearson, D; Poole, B; Richardson, R; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J; Weir, J


    The dielectric wall accelerator (DWA) system being developed at the Lawrence Livermore National Laboratory (LLNL) uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. High electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The system is capable of accelerating any charge to mass ratio particle. Applications of high gradient proton and electron versions of this accelerator will be discussed. The status of the developmental new technologies that make the compact system possible will be reviewed. These include, high gradient vacuum insulators, solid dielectric materials, photoconductive switches and compact proton sources.

  9. 基于分岔理论的孤立微网静态电压稳定性分析%Analysis on static voltage stability of isolated micro-grid based on bifurcation theory

    Institute of Scientific and Technical Information of China (English)

    李苏川; 吕智林; 谭颖


    为了深入研究孤立微网的静态电压稳定性问题,将分岔理论应用于微网静态电压稳定性分析研究。以鞍结分岔点作为电压稳定临界点,采用连续潮流( CPF)算法对四节点小型孤立微网进行电压稳定性分析,追踪出该系统的PU曲线,并根据特征根来判断该曲线上是否存在鞍结分岔点。分别计算出含SVC和不含SVC系统的电压稳定极限,得出负荷节点处电压稳定裕度。由实验结果可以看出,随着负荷参数的不断增大,负荷所需功率和发电机的输出功率也会随之增大,当达到它的传输极限时就会产生鞍结分岔现象,从而导致系统电压出现跌落甚至崩溃的现象。结果表明,利用上述方法可以有效地计算出孤立微网的电压稳定极限,并且使用SVC控制器可以提高系统电压稳定性。%In order to study the problem of static voltage stability of isolated micro-grid, the bifurca-tion theory is applied. The saddle node bifurcation point is used as the voltage collapse critical point while using continuous power flow ( CPF) algorithm to analyze the voltage stability of a small isolated micro-grid with four nodes. Then by tracing the PU curve of the system and according to the charac-teristics of the root the saddle node bifurcation point in the curve is determined. The stability limit of the SVC and non SVC system voltage are calculated respectively to obtain the voltage stability margin of load node. The experiments show that with the increase of the load parameters, the required pow-er of the load and the output power of the generator will increase. Then the saddle node bifurcation will occur when the transmission limit which causes the system voltage to fall or collapse. The results of simulations show that the voltage stability limit of isolated micro grid can be calculated by using this method. And by using SVC controller the stability of system voltage can be improved.

  10. KH550-GO复合栅介质低压氧化物薄膜晶体管%Low-voltage oxide thin film transistor made of KH550-GO composite dielectrics

    Institute of Scientific and Technical Information of China (English)

    黄钰凯; 凌智勇; 邵枫; 温娟


    Spin coated-processed silane coupling agents (KH550-GO) composite proton conductor film shows a large specific gate capacitance of 2.18×10–6F/cm2due to the interfacial electric-double-layer effect. Low-voltage oxide (IZO) TFTs gated by a KH550-GO composite proton conductor film were self-assembled by only one shadow-mask. Electrical characteristics of the devices were measured by a Keithley 4200 SCS semiconductor parameter analyzer at room temperature under the condition of darkness. The results show that KH550-GO oxide thin film transistors possess good electrical properties, the operating voltage is only 2 V, the saturation current, the subthreshold gate voltage swing, the current on/off ratio, and the field-effect mobility are estimated to be 580 µA, 108 mV/dec, 4×107, and 16.7 cm2·V−1·s−1, respectively.%采用旋涂法制备硅烷偶联剂-氧化石墨烯(KH550-GO)新型复合栅介质薄膜,由于栅介质层和沟道层界面处明显的双电层效应,单位面积电容高达2.18×10–6 F/cm2。通过自组装法,借助磁控溅射仪,仅需一次掩膜,即可同时生成晶体管的沟道与源漏电极。利用半导体参数分析仪在室温黑暗的条件下测量该晶体管的电学特性,结果表明,KH550-GO栅介质氧化物薄膜晶体管具有优良的电学性能,其工作电压仅为2 V、饱和电流为580µA、亚阈值摆幅108 mV/dec、开关比4×107、场效应迁移率16.7 cm2·V−1·s−1。

  11. Effect of the Dielectric Inhomogeneity Factor's Range on the Electrical Tree Evolution in Solid Dielectrics

    Directory of Open Access Journals (Sweden)

    Hemza Medoukali


    Full Text Available The main contribution of the presented paper is to investigate the influence of the Dielectric Inhomogeneity Factor on the electrical tree evolution in solid dielectrics using cellular automata. We have a sample of the XLPE which is located between needle-to-plane electrodes under DC voltage. The electrical tree emanates from the end of the needle in which the electric stress attains a dielectric strength of the material. At every time step, Laplace's equation is solved to calculate the potential distribution which changes according to electrical tree development. Dynamic simulations clearly demonstrate the influence of the range of the Dielectric Inhomogeneity Factor on the electrical tree growth. Simulation results confirm the published technical literature.

  12. Dielectric breakdown in nano-porous thin films (United States)

    Borja, Juan Pablo

    Unknown to most computer users and mobile device enthusiasts, we have finally entered into a critical age of chip manufacturing. January of 2014 marks the official start of the quest by the semiconductor industry to successfully integrate sub 14nm process technology nodes in accordance to the International Technology Roadmap for Semiconductors (ITRS). The manufacturing of nano-scale features represents a major bottleneck of its own. However, a bigger challenge lies in reliably isolating the massive chip interconnect network. The present work is aimed at generating a theoretical and experimental framework to predict dielectric breakdown for thin films used in computer chip components. Here, a set of experimental techniques are presented to assess and study dielectric failure in novel thin films. A theory of dielectric breakdown in thin nano-porous films is proposed to describe combined intrinsic and metal ion catalyzed failure. This theory draws on experimental evidence as well as fundamental concepts from mass and electronic charge transport. The drift of metal species was found to accelerate intrinsic dielectric failure. The solubility of metals species such as Cu was found to range from 7.0x1025 ions/m3 to 1.86x1026 ions/m3 in 7% porous SiCOH films. The diffusion coefficient for Cu species was found to span from 4.2x10-19 m2/s to 1.86x10-21 m2/s. Ramped voltage stress experiments were used to identify intrinsic failure from metal catalyzed failure. Intrinsic breakdown is defined when time to failure against applied field ramp rate results in ∂(ln(TTF))/∂(ln(R)) ≈ -1. Intrinsic failure was studied using Au. Here, ∂(ln(TTF))/∂(ln(R)) ≈ -0.95, which is an experimental best case scenario for intrinsic failure. Au is commonly reluctant to ionize which means that failure occurs in the absence of ionic species. Metal catalyzed failure was investigated using reactive electrodes such as Cu, and Ag. Here, trends for ∂(ln(TTF))/∂(ln(R)) significantly

  13. Battery powered high output voltage bidirectional flyback converter for cylindrical DEAP actuator

    DEFF Research Database (Denmark)

    Huang, Lina; Thummala, Prasanth; Zhang, Zhe;


    DEAP (Dielectric Electro Active Polymer) actuator is essentially a capacitive load and can be applied in various actuation occasions. However, high voltage is needed to actuate it. In this paper, a high voltage bidirectional flyback converter with low input voltage is presented. The fundamental....... The design parameters for flyback transformer and snubber circuits are illustrated. Moreover, the experimental waveforms are provided....

  14. 一种简单的光电隔离RS-232电平转换接口设计%A kind of simple photoelectric-isolated RS-232 voltage conversion interface design

    Institute of Scientific and Technical Information of China (English)

    王三胜; 顾彪


    A design method of a kind of practical photoelectric-isolated RS-232 voltage conversion interface is introduced .Making use of the method ,a connection circuit is designed, which does not need RS-232 voltage converter and fulfills voltage conversion by photoelectric coupler directly. At the same time, hardware connection circuit,complete communication protocols and software design of communication between MCS-51 single-chip microcomputer and PC computer are given.%介绍一种简单实用的光电隔离RS-232电平转换接口设计方法。采用该方法设计的接口电路不需要RS-232电平转换器,由光电耦合器直接完成电平转换.并给出一个MCS-51单片机与PC机通讯的硬件连接电路、完整的通讯协议和软件设计流程。

  15. Accurate Switched-Voltage voltage averaging circuit


    金光, 一幸; 松本, 寛樹


    Abstract ###This paper proposes an accurate Switched-Voltage (SV) voltage averaging circuit. It is presented ###to compensated for NMOS missmatch error at MOS differential type voltage averaging circuit. ###The proposed circuit consists of a voltage averaging and a SV sample/hold (S/H) circuit. It can ###operate using nonoverlapping three phase clocks. Performance of this circuit is verified by PSpice ###simulations.

  16. Isolation

    DEFF Research Database (Denmark)

    Agerholm, Frank Juul


    Næringsstoffet har i dette nummer sat fokus på ”velvære i vinterkulden”, ”indendørsaktiviteter” og ”fedtafgift”. I klummen vises det, at disse tre fokusområder, der for en umiddelbar betragtning måske nok synes noget uensartede, falder sammen i ét tema: Isolation!......Næringsstoffet har i dette nummer sat fokus på ”velvære i vinterkulden”, ”indendørsaktiviteter” og ”fedtafgift”. I klummen vises det, at disse tre fokusområder, der for en umiddelbar betragtning måske nok synes noget uensartede, falder sammen i ét tema: Isolation!...

  17. Bistable dielectric elastomer minimum energy structures (United States)

    Zhao, Jianwen; Wang, Shu; McCoul, David; Xing, Zhiguang; Huang, Bo; Liu, Liwu; Leng, Jinsong


    Dielectric elastomer minimum energy structures (DEMES) can realize large angular deformations by small voltage-induced strains, which make them an attractive candidate for use as soft actuators. If the task only needs binary action, the bistable structure will be an efficient solution and can save energy because it requires only a very short duration of voltage to switch its state. To obtain bistable DEMES, a method to realize the two stable states of traditional DEMES is provided in this paper. Based on this, a type of symmetrical bistable DEMES is proposed, and the required actuation pulse duration is shorter than 0.1 s. When a suitable mass is attached to end of the DEMES, or two layers of dielectric elastomer are affixed to both sides of the primary frame, the DEMES can realize two stable states and can be switched by a suitable pulse duration. To calculate the required minimum pulse duration, a mathematical model is provided and validated by experiment.

  18. Study of the conductivity of irradiated dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Maslov, V.V.; Ivanov, N.V.; Shelenin, A.V.


    The processes of ionization of air, metals and dielectrics arising from Gamma irradiation are analyzed. The effect of these processes on the measurement of the electrical conductivity of the dielectrics which are irradiated is evaluated. The maximum current which can be carried by an ionized gas is proportional to the radiation dose, gas pressure and reciprocal gas temperature. It is much more difficult to define the voltage developing between the two metal objects exposed to ionizing radiation due to such factors as the variation in resistance with dose, difficulty in defining the coefficient characterizing the accumulated charge, which depends on the nature of the metal, its shape, thickness and many other factors. Results of a simple calculation are presented in tabular form for aluminum. In some cases the voltage which develops is proportional to dose, in other cases--to the square root of dose, in still other cases--somewhere in between. 3 tables, 6 references.

  19. Effect of profile and size of isolation trench on the optical and electrical performance of GaN-based high-voltage LEDs (United States)

    Zhou, Shengjun; Zheng, Chenju; Lv, Jiajiang; Liu, Yingce; Yuan, Shu; Liu, Sheng; Ding, Han


    Four types of HV-LEDs with different isolation trench width were presented. The isolation trench with an oblique angle of 45.6° was obtained using a combination of Cl2/BCl3 plasma chemistry and a thermally reflowed photoresist mask layer, enabling conformal metal lines coverage across the isolation trench. The effect of isolation trench width on the optical and electrical characteristics of HV LEDs was also investigated. A quantitative model was developed to analyze light coupling propagation phenomenon occurring within HV LEDs. The suppression of light coupling propagation among adjacent LED cells was achieved by extending isolation trench width from 3.81 μm to 12.30 μm, which improved light extraction efficiency and thus increased light output power of HV LEDs. However, the significantly increasing loss of MQW active region area, which was caused by further extending isolation trench width from 12.30 μm to 40.49 μm, decreased light output power of HV LEDs.

  20. Characterization of DBD Plasma Actuators Performance without External Flow . Part I; Thrust-Voltage Quadratic Relationship in Logarithmic Space for Sinusoidal Excitation (United States)

    Ashpis, David E.; Laun, Matthew C.


    We present results of thrust measurements of Dielectric Barrier Discharge (DBD) plasma actuators. We have used a test setup, measurement, and data processing methodology that we developed in prior work. The tests were conducted with High Density Polyethylene (HDPE) actuators of three thicknesses. The applied voltage driving the actuators was a pure sinusoidal waveform. The test setup was suspended actuators with a partial liquid interface. The tests were conducted at low ambient humidity. The thrust was measured with an analytical balance and the results were corrected for anti-thrust to isolate the plasma generated thrust. Applying this approach resulted in smooth and repeatable data. It also enabled curve fitting that yielded quadratic relations between the plasma thrust and voltage in log-log space at constant frequencies. The results contrast power law relationships developed in literature that appear to be a rough approximation over a limited voltage range.

  1. Dielectrics in electric fields

    CERN Document Server

    Raju, Gorur G


    Discover nontraditional applications of dielectric studies in this exceptionally crafted field reference or text for seniors and graduate students in power engineering tracks. This text contains more than 800 display equations and discusses polarization phenomena in dielectrics, the complex dielectric constant in an alternating electric field, dielectric relaxation and interfacial polarization, the measurement of absorption and desorption currents in time domains, and high field conduction phenomena. Dielectrics in Electric Fields is an interdisciplinary reference and text for professionals and students in electrical and electronics, chemical, biochemical, and environmental engineering; physical, surface, and colloid chemistry; materials science; and chemical physics.

  2. Lattices of dielectric resonators

    CERN Document Server

    Trubin, Alexander


    This book provides the analytical theory of complex systems composed of a large number of high-Q dielectric resonators. Spherical and cylindrical dielectric resonators with inferior and also whispering gallery oscillations allocated in various lattices are considered. A new approach to S-matrix parameter calculations based on perturbation theory of Maxwell equations, developed for a number of high-Q dielectric bodies, is introduced. All physical relationships are obtained in analytical form and are suitable for further computations. Essential attention is given to a new unified formalism of the description of scattering processes. The general scattering task for coupled eigen oscillations of the whole system of dielectric resonators is described. The equations for the  expansion coefficients are explained in an applicable way. The temporal Green functions for the dielectric resonator are presented. The scattering process of short pulses in dielectric filter structures, dielectric antennas  and lattices of d...

  3. Optomechanics of Levitated Dielectric Particles

    CERN Document Server

    Yin, Zhang-qi; Li, Tongcang


    We review recent works on optomechanics of optically trapped microspheres and nanoparticles in vacuum, which provide an ideal system for studying macroscopic quantum mechanics and ultrasensitive force detection. An optically trapped particle in vacuum has an ultrahigh mechanical quality factor as it is well-isolated from the thermal environment. Its oscillation frequency can be tuned in real time by changing the power of the trapping laser. Furthermore, an optically trapped particle in vacuum may rotate freely, a unique property that does not exist in clamped mechanical oscillators. In this review, we will introduce the current status of optical trapping of dielectric particles in air and vacuum, Brownian motion of an optically trapped particle at room temperature, Feedback cooling and cavity cooling of the Brownian motion. We will also discuss about using optically trapped dielectric particles for studying macroscopic quantum mechanics and ultrasensitive force detection. Applications range from creating macr...

  4. Study of the synergistic effect in dielectric breakdown property of CO2-O2 mixtures (United States)

    Zhao, Hu; Deng, Yunkun; Lin, Hui


    Sulfur hexafluoride, SF6, is a common dielectric medium for high-voltage electrical equipment, but because it is a potent greenhouse gas, it is important to find less environmentally harmful alternatives. In this paper we explore the use of CO2 and O2 as one alternative. We studied the synergistic effect in a mixture of CO2 and O2 from both macroscopic and microscopic perspectives. The effect leads to a dielectric strength of the mixture being greater than the linear interpolation of the dielectric strengths of the two isolated gases. We analyzed the critical reduced electric field strength, (E/N)cr, the breakdown gas pressure reduced electric field, E/p, and the breakdown electron temperature, Tb, and their synergistic effect coefficients for various CO2 concentrations and various products of the gas pressure times the gap distance (pd). A gas discharge and breakdown mechanism in a homogenous electric field is known to be controlled by the generation and disappearance of free electrons, which strongly depend on the electron temperature. The results indicate that adding a small amount of O2 to CO2 can effectively improve the value of (E/N)cr and bring a clear synergistic effect. In addition, significantly different variation trends of the synergistic effect in the E/p and Tb of CO2-O2 mixtures at various CO2 concentrations and pd values were also observed.

  5. Modeling shape-memory behavior of dielectric elastomers (United States)

    Xiao, Rui


    In this study, we present a constitutive model to couple the shape memory and dielectric behaviors of polymers. The model adopted multiple relaxation processes and temperature-dependent relaxation time to describe the glass transition behaviors. The model was applied to simulate the thermal-mechanical-electrical behaviors of the dielectric elastomer VHB 4905. We investigated the influence of deformation temperature, voltage rate, relaxation time on the electromechanical and shape-memory behavior of dielectric elastomers. This work provides a method for combining the shape-memory properties and electroactive polymers, which can expand the applications of these soft active materials.

  6. Self-Healing, High-Permittivity Silicone Dielectric Elastomer

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Skov, Anne Ladegaard


    or cuts made directly to the material due to the reassembly of the ionic bonds that are broken during damage. The dielectric elastomers presented in this paper pave the way to increased lifetimes and the ability of dielectric elastomers to survive millions of cycles in high-voltage conditions....... possesses high dielectric permittivity and consists of an interpenetrating polymer network of silicone elastomer and ionic silicone species that are cross-linked through proton exchange between amines and acids. The ionically cross-linked silicone provides self-healing properties after electrical breakdown...

  7. Characteristics of radio-frequency atmospheric pressure dielectric-barrier discharge with dielectric electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, S., E-mail:, E-mail:; Qazi, H. I. A.; Badar, M. A. [Department of Physics, University of Sargodha, 40100 Sargodha (Pakistan)


    An experimental investigation to characterize the properties and highlight the benefits of atmospheric pressure radio-frequency dielectric-barrier discharge (rf DBD) with dielectric electrodes fabricated by anodizing aluminium substrate is presented. The current-voltage characteristics and millisecond images are used to distinguish the α and γ modes. This atmospheric rf DBD is observed to retain the discharge volume without constriction in γ mode. Optical emission spectroscopy demonstrates that the large discharge current leads to more abundant reactive species in this plasma source.

  8. Nanoscale dielectric-graphene-dielectric tunable infrared waveguide with ultrahigh refractive indices. (United States)

    Zhu, Bofeng; Ren, Guobin; Zheng, Siwen; Lin, Zhen; Jian, Shuisheng


    We propose in this paper a dielectric-graphene-dielectric tunable infrared waveguide based on multilayer metamaterials with ultrahigh refractive indices. The waveguide modes with different orders are systematically analyzed with numerical simulations based on both multilayer structures and effective medium approach. The waveguide shows hyperbolic dispersion properties from mid-infrared to far-infrared wavelength, which means the modes with ultrahigh mode indices could be supported in the waveguide. Furthermore, the optical properties of the waveguide modes could be tuned by the biased voltages on graphene layers. The waveguide may have various promising applications in the quantum cascade lasers and bio-sensing.

  9. Synergistic antiarrhythmic effect of combining inhibition of Ca(2+)-activated K(+) (SK) channels and voltage-gated Na(+) channels in an isolated heart model of atrial fibrillation

    DEFF Research Database (Denmark)

    Kirchhoff, Jeppe Egedal; Goldin Diness, Jonas; Sheykhzade, Majid


    be subefficacious as monotherapy, may prevent atrial fibrillation (AF) and have reduced proarrhythmic potential in the ventricles. METHODS: Subefficacious concentrations of ranolazine, flecainide, and lidocaine were tested alone or in combination with the SK channel blocker N-(pyridin-2-yl)-4-(pyridin-2-yl...... of the adverse effect profile could be an additional advantage if compound concentrations could be reduced. OBJECTIVE: The purpose of this study was to test the hypothesis that combined inhibition of Ca(2+)-activated K(+) channels (SK channels) and voltage-gated Na(+) channels, in concentrations that would......)thiazol-2-amine (ICA) in a Langendorff-perfused guinea pig heart model in which AF was induced after acetylcholine application and burst pacing. RESULTS: AF duration was reduced when both flecainide and ranolazine were combined with ICA in doses that did not reduce AF as monotherapy. At higher...

  10. An Ultra-Compact Marx-Type High-Voltage Generator

    Energy Technology Data Exchange (ETDEWEB)

    Goerz, D; Ferriera, T; Nelson, D; Speer, R; Wilson, M


    This paper discusses the design of an ultra-compact, Marx-type, high-voltage generator. This system incorporates high-performance components that are closely coupled and integrated into an extremely compact assembly. Low profile, custom ceramic capacitors with coplanar extended electrodes provide primary energy storage. Low-inductance, spark-gap switches incorporate miniature gas cavities imbedded within the central region of the annular shaped capacitors, with very thin dielectric sections separating the energy storage capacitors. Carefully shaped electrodes and insulator surfaces are used throughout to minimize field enhancements, reduce fields at triple-point regions, and enable operation at stress levels closer to the intrinsic breakdown limits of the dielectric materials. Specially shaped resistors and inductors are used for charging and isolation during operation. Forward-coupling ceramic capacitors are connected across successive switch-capacitor-switch stages to assist in switching. Pressurized SF, gas is used for electrical insulation in the spark-gap switches and throughout the unit. The pressure housing is constructed entirely of dielectric materials, with segments that interlock with the low-profile switch bodies to provide an integrated support structure for all of the components. This ultra-compact Marx generator employs a modular design that can be sized as needed for a particular application. Units have been assembled with 4, 10, and 30 stages and operated at levels up to 100 kV per stage.

  11. Ropivacaine-Induced Contraction Is Attenuated by Both Endothelial Nitric Oxide and Voltage-Dependent Potassium Channels in Isolated Rat Aortae

    Directory of Open Access Journals (Sweden)

    Seong-Ho Ok


    Full Text Available This study investigated endothelium-derived vasodilators and potassium channels involved in the modulation of ropivacaine-induced contraction. In endothelium-intact rat aortae, ropivacaine concentration-response curves were generated in the presence or absence of the following inhibitors: the nonspecific nitric oxide synthase (NOS inhibitor Nω-nitro-L-arginine methyl ester (L-NAME, the neuronal NOS inhibitor Nω-propyl-L-arginine hydrochloride, the inducible NOS inhibitor 1400W dihydrochloride, the nitric oxide-sensitive guanylyl cyclase (GC inhibitor ODQ, the NOS and GC inhibitor methylene blue, the phosphoinositide-3 kinase inhibitor wortmannin, the cytochrome p450 epoxygenase inhibitor fluconazole, the voltage-dependent potassium channel inhibitor 4-aminopyridine (4-AP, the calcium-activated potassium channel inhibitor tetraethylammonium (TEA, the inward-rectifying potassium channel inhibitor barium chloride, and the ATP-sensitive potassium channel inhibitor glibenclamide. The effect of ropivacaine on endothelial nitric oxide synthase (eNOS phosphorylation in human umbilical vein endothelial cells was examined by western blotting. Ropivacaine-induced contraction was weaker in endothelium-intact aortae than in endothelium-denuded aortae. L-NAME, ODQ, and methylene blue enhanced ropivacaine-induced contraction, whereas wortmannin, Nω-propyl-L-arginine hydrochloride, 1400W dihydrochloride, and fluconazole had no effect. 4-AP and TEA enhanced ropivacaine-induced contraction; however, barium chloride and glibenclamide had no effect. eNOS phosphorylation was induced by ropivacaine. These results suggest that ropivacaine-induced contraction is attenuated primarily by both endothelial nitric oxide and voltage-dependent potassium channels.

  12. The physics of positively biased conductors surrounded by dielectrics in contact with a plasma (United States)

    Hastings, Daniel E.; Chang, Patrick


    The physics of a positively biased conductor surrounded by dielectrics in contact with plasma is investigated. It is shown that because of the presence of secondary emission from the surrounding dielectrics, the voltage of the surfaces near the conductor has three solutions. The high- and low-voltage solutions are stable, while the intermediate-voltage solution is unstable. This theory is applied to explain the snapover effect observed on high-voltage solar arrays that involve the use of highly biased surfaces in contact with the space environment.



    Erfani, Rasool


    The standard dielectric barrier discharge (DBD) plasma actuator, in which an asymmetric arrangement of electrodes leads to momentum coupling into the surrounding air, has already demonstrated its capability for flow control. The effect of some parameters such as dielectric thickness, dielectric temperature, voltage amplitude, driving frequency, different configurations and arrangements on actuator performance are examined. The new configuration of DBD which uses multiple encapsulated electrod...

  14. Silicone elastomers with superior softness and dielectric properties

    DEFF Research Database (Denmark)

    Yu, Liyun; Madsen, Frederikke Bahrt; Zakaria, Shamsul Bin;

    of electrical breakdown and achievable strain.[2]In this work, three liquid additives - inert silicone oil, chloropropyl-functional silicone oil, and synthesized chloropropyl-functional copolymer - were blended into commercial silicone elastomers, and their properties were investigated.The functional groups......Dielectric elastomers (DEs) change their shape and size under a high voltage or reversibly generate a high voltage when deformed. The obstacle of high driving voltages, however, limits the commercial viability of the technology at present. Driving voltage can be lowered by decreasing the Young......’s modulus and increasing the dielectric permittivity of silicone elastomers. One such prominent method of modifying the properties is by adding suitable additives.[1] The major drawbacks for adding solid fillers are agglomeration and increasing stiffness which is often accompanied by the decrease...

  15. Silicone elastomers with superior softness and dielectric properties

    DEFF Research Database (Denmark)

    Yu, Liyun; Madsen, Frederikke Bahrt; Zakaria, Shamsul Bin;

    of electrical breakdown and achievable strain.[2] In this work, three liquid additives - inert silicone oil, chloropropyl-functional silicone oil, and synthesized chloropropyl-functional copolymer - were blended into commercial silicone elastomers, and their properties were investigated.The functional groups......Dielectric elastomers (DEs) change their shape and size under a high voltage or reversibly generate a high voltage when deformed. The obstacle of high driving voltages, however, limits the commercial viability of the technology at present. Driving voltage can be lowered by decreasing the Young......’s modulus and increasing the dielectric permittivity of silicone elastomers. One such prominent method of modifying the properties is by adding suitable additives. [1] The major drawbacks for adding solid fillers are agglomeration and increasing stiffness which is often accompanied by the decrease...

  16. Experimental investigation of SDBD plasma actuator driven by AC high voltage with a superimposed positive pulse bias voltage (United States)

    Qi, Xiao-Hua; Yan, Hui-Jie; Yang, Liang; Hua, Yue; Ren, Chun-Sheng


    In this work, a driven voltage consisting of AC high voltage with a superimposed positive pulse bias voltage ("AC+ Positive pulse bias" voltage) is adopted to study the performance of a surface dielectric barrier discharge plasma actuator under atmospheric conditions. To compare the performance of the actuator driven by single-AC voltage and "AC+ Positive pulse bias" voltage, the actuator-induced thrust force and power consumption are measured as a function of the applied AC voltage, and the measured results indicate that the thrust force can be promoted significantly after superimposing the positive pulse bias voltage. The physical mechanism behind the thrust force changes is analyzed by measuring the optical properties, electrical characteristics, and surface potential distribution. Experimental results indicate that the glow-like discharge in the AC voltage half-cycle, next to the cycle where a bias voltage pulse has been applied, is enhanced after applying the positive pulse bias voltage, and this perhaps is the main reason for the thrust force increase. Moreover, surface potential measurement results reveal that the spatial electric field formed by the surface charge accumulation after positive pulse discharge can significantly affect the applied external electric field, and this perhaps can be responsible for the experimental phenomenon that the decrease of thrust force is delayed by pulse bias voltage action after the filament discharge occurs in the glow-like discharge region. The schlieren images further verify that the actuator-induced airflow velocity increases with the positive pulse voltage.

  17. PREFACE: Dielectrics 2009: Measurement Analysis and Applications (United States)

    Vaughan, Alun; Williams, Graham


    The conference Dielectrics 2009: Measurements, Analysis and Applications represents a significant milestone in the evolution of dielectrics research in the UK. It is reasonable to state that the academic study of dielectrics has led to many fundamental advances and that dielectric materials underpin the modern world in devices ranging from field effect transistors, which operate at extremely high fields, albeit low voltages, to the high voltage plants that provide the energy that powers our economy. The origins of the Dielectrics Group of the Institute of Physics (IOP), which organized this conference, can be traced directly back to the early 1960s, when Professor Mansel Davies was conducting research into the dielectric relaxation behaviour of polar liquids and solids at The Edward Davies Chemical Laboratories of the University College of Wales, Aberystwyth. He was already well-known internationally for his studies of molecular structure and bonding of small molecules, using infra-red-spectroscopy, and of the physical properties of hydrogen-bonded liquids and solids, using thermodynamic methods. Dielectric spectroscopy was a fairly new area for him and he realized that opportunities for scientists in the UK to gather together and discuss their research in this developing area of physical chemistry/chemical physics were very limited. He conceived the idea of forming a Dielectrics Discussion Group (DDG), which would act as a meeting point and provide a platform for dielectrics research in the UK and beyond and, as a result, a two-day Meeting was convened in the spring of 1968 at Gregynog Hall of the University of Wales, near Newtown, Montgomeryshire. It was organized by Mansel Davies, Alun Price and Graham Williams, all physical chemists from the UCW, Aberystwyth. Fifty scientists attended, being a mix of physical chemists, theoretical chemists, physicists, electrical engineers, polymer and materials scientists, all from the UK, except Dr Brendan Scaife of Trinity

  18. Dielectric characterisation of human tissue samples

    NARCIS (Netherlands)

    Rossum, W.L. van; Nennie, F.; Deiana, D.; Veen, A.J. van der; Monni, S.


    The electrical properties of tissues samples are required for investigation and simulation purposes in biomedical applications of EM sensors. While available open literature mostly deals with ex-vivo characterization of isolated tissues, knowledge on dielectric properties of these tissues in their o

  19. Characterization of dielectric materials

    Energy Technology Data Exchange (ETDEWEB)

    King, Danny J.; Babinec, Susan; Hagans, Patrick L.; Maxey, Lonnie C.; Payzant, Edward A.; Daniel, Claus; Sabau, Adrian S.; Dinwiddie, Ralph B.; Armstrong, Beth L.; Howe, Jane Y.; Wood, III, David L.; Nembhard, Nicole S.


    A system and a method for characterizing a dielectric material are provided. The system and method generally include applying an excitation signal to electrodes on opposing sides of the dielectric material to evaluate a property of the dielectric material. The method can further include measuring the capacitive impedance across the dielectric material, and determining a variation in the capacitive impedance with respect to either or both of a time domain and a frequency domain. The measured property can include pore size and surface imperfections. The method can still further include modifying a processing parameter as the dielectric material is formed in response to the detected variations in the capacitive impedance, which can correspond to a non-uniformity in the dielectric material.

  20. Experimental Observation of Travelling Hexagon Patterns in Dielectric Barrier Discharge

    Institute of Scientific and Technical Information of China (English)

    董丽芳; 贺亚峰; 尹增谦; 柴志方


    Travelling hexagon patterns have been observed in dielectric barrier discharge in an air-argon mixture. The phase diagram of hexagon pattern appearance as functions of applied voltage and air concentration is given. The spatial frequency of hexagon pattern increases with increasing applied voltage and air concentration. The current waveforms of hexagon pattern also vary with the air concentration. The drift velocity of travelling hexagon pattern changes from 4mm/s to 18mm/s.

  1. Absorption Voltages and Insulation Resistance in Ceramic Capacitors with Cracks (United States)

    Teverovsky, Alexander


    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.

  2. Analysis on Dielectric Withstand Cascaded DC High-Voltage Generator for ±1100 kV UHVDC Converter Valve Test%±1100kV特高压直流换流阀试验用高压直流串级发生器的绝缘耐压分析

    Institute of Scientific and Technical Information of China (English)

    顾灶根; 周军川; 温传新; 温家良


    为在实验室条件下进行±1100 kV特高压换流阀绝缘型式试验,需要对用于试验的高压直流串级发生器能否满足绝缘耐压要求进行分析.利用ANSOFT SIMPLORER软件对装置进行电路理论分析计算以及利用ANSOFTMAXWELL有限元软件对其进行三维结构的电场强度仿真 分析.仿真得到最大场强为22.62 kV/cm,与空气击穿场强25 kV/cm较接近,结果与装置输出1843 kV时,装置顶部与实验室顶部钢梁间的空气间隙空气被击穿相吻合.为进一步降低场强,对装置进行优化分析,并得出优化后的电场强度最大值为20.66 kV/cm,低于空气击穿场强.因此认为,若不考虑空气温湿度等条件的影响,在现有试验室条件下,试验室设备具备±1100 kV特高压换流阀绝缘耐压试验的能力.%To make the dielectric test on ±1 100 kV UHVDC converter valve in laboratory environment, it is necessary to analyze whether the dielectric withstand of cascaded DC high-voltage (HV) generator used in the test can be met. Based on the principle of the cascaded DC HV generator, its topological model is established by ANSOFT SIMPLORER, and above earth potentials at different positions of metal shield cases of silicon rectifier stacks and those at the tops of insulative posts of the HV generator are obtained; the three-dimensional simulation analysis on the distribution of electric field strength of the generator is performed by FEM software ANSOFT MAXWELL. Simulation results show that the maximum electric field strength around the HV generator is 22.62 kV/cm that is close to 25 kV/cm, the breakdown field strength of air, and such a result conforms to the case that the air gap between the top of the HV generator and the top steel beam of the laboratory was broken down while the output of the HV generator was 1 843 kV. To decrease the electric field strength in the air, optimization analysis on HV generator is performed and the result shows that the maximum electric

  3. Reconstitution of neurotoxin-modulated ion transport by the voltage-regulated sodium channel isolated from the electroplax of Electrophorus electricus. (United States)

    Rosenberg, R L; Tomiko, S A; Agnew, W S


    The functional reconstitution of the voltage-regulated Na channel purified from the electroplax of Electrophorus electricus is described. Reconstitution was achieved by removing detergent with Bio-Beads SM-2 followed by freeze-thaw-sonication in the presence of added liposomes. This preparation displayed heat-stable binding of 3H-labeled tetrodotoxin (TTX) (Kd = 33 nM). 22Na+ influx was stimulated 2- to 5-fold by alkaloid neurotoxins and blocked by TTX. Veratridine activated Na+ influx with a K1/2 of 18 microM, and this activation was blocked by TTX precisely in parallel with specific [3H]TTX binding. Batrachotoxin stimulated 22Na+ flux more effectively than did veratridine. No effect of the peptide anemone toxin II was found. Insertion of the Na channel into membranes resulted in 60-70% of the TTX-binding sites facing the vesicle exterior. Thus, external TTX partially inhibited flux, whereas blockade was complete when TTX was also equilibrated with the vesicle interior. The lipid-soluble local anesthetics tetracaine and dibucaine inhibited flux completely. QX-222, a charged derivative of lidocaine, blocked only a fraction of the channels, apparently those oriented inside-out. Purified samples were predominantly composed of the Mr 260,000-300,000 glycopeptide but contained variable quantities of smaller peptides. Veratridine-dependent flux and peptide compositions were determined on fractions across a gel filtration column profile. Stimulated flux codistributed only with the large peptide. Images PMID:6322191

  4. Resonant dielectric metamaterials (United States)

    Loui, Hung; Carroll, James; Clem, Paul G; Sinclair, Michael B


    A resonant dielectric metamaterial comprises a first and a second set of dielectric scattering particles (e.g., spheres) having different permittivities arranged in a cubic array. The array can be an ordered or randomized array of particles. The resonant dielectric metamaterials are low-loss 3D isotropic materials with negative permittivity and permeability. Such isotropic double negative materials offer polarization and direction independent electromagnetic wave propagation.

  5. Method of making dielectric capacitors with increased dielectric breakdown strength

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Beihai; Balachandran, Uthamalingam; Liu, Shanshan


    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.

  6. High Efficiency Control Strategy for Isolated Full-Bridge-Boost Converter Suitable for Wide Input Voltage Range%宽输入电压范围下隔离型全桥Boost变换器的高效率控制

    Institute of Scientific and Technical Information of China (English)

    姚川; 阮新波; 王学华


    A family of isolated Buck-Boost converters is proposed to be suitable for the application,where the input voltage range is wide and galvanic isolation is required in this paper.Full-Bridge(FB)-Boost converter is analyzed as one of the typical topologies.Considering the duty cycle loss,an improved two-edge modulation strategy based on phase-shift control is proposed to minimize the inductor current ripple over the input voltage range.In order to achieve the reliability and efficiency of this converter,a 3-mode dual-frequency control scheme is proposed.Under the 3-mode dual-frequency control scheme,the input voltage is divided into three regions,i.e.the low,medium and high voltage rang,and corresponding operating modes are Boost,FB-Boost and FB modes respectively.As the inductor current ripple in FB-Boost mode is much smaller,the switching frequency of the boost cell in this mode can be lowered to reduce the switching loss and further improve the efficiency.To verify the effectiveness of the design and control,a 250~500V input,360V output and 6kW rated power prototype is fabricated.High efficiency can be achieved all over the input voltage range,and the highest efficiency is 97.2%.%本文提出了一族隔离型的Buck-Boost变换器以适应宽输入电压范围并要求隔离的应用场合,以全桥(Full-Bridge,FB)Boost变换器作为其典型电路之一在文中展开分析。考虑占空比的丢失,提出了基于移相控制的双沿调制策略以减小整个输入电压范围内的电感电流脉动。为实现变换器可靠高效的工作,提出了三模式双频控制策略。三模式双频控制策略下,输入电压被分为低、中、高三个电压区间,分别对应于FB-Boost变换器的Boost、FB-Boost和FB三个工作模式。由于FB-Boost模式下电感电流脉动较小,可以降低该模式下Boost单元的开关频率以减小开关损耗,进一步提高效率。为验证设计和控制策略的有效

  7. Ion implanted dielectric elastomer circuits (United States)

    O'Brien, Benjamin M.; Rosset, Samuel; Anderson, Iain A.; Shea, Herbert R.


    Starfish and octopuses control their infinite degree-of-freedom arms with panache—capabilities typical of nature where the distribution of reflex-like intelligence throughout soft muscular networks greatly outperforms anything hard, heavy, and man-made. Dielectric elastomer actuators show great promise for soft artificial muscle networks. One way to make them smart is with piezo-resistive Dielectric Elastomer Switches (DES) that can be combined with artificial muscles to create arbitrary digital logic circuits. Unfortunately there are currently no reliable materials or fabrication process. Thus devices typically fail within a few thousand cycles. As a first step in the search for better materials we present a preliminary exploration of piezo-resistors made with filtered cathodic vacuum arc metal ion implantation. DES were formed on polydimethylsiloxane silicone membranes out of ion implanted gold nano-clusters. We propose that there are four distinct regimes (high dose, above percolation, on percolation, low dose) in which gold ion implanted piezo-resistors can operate and present experimental results on implanted piezo-resistors switching high voltages as well as a simple artificial muscle inverter. While gold ion implanted DES are limited by high hysteresis and low sensitivity, they already show promise for a range of applications including hysteretic oscillators and soft generators. With improvements to implanter process control the promise of artificial muscle circuitry for soft smart actuator networks could become a reality.

  8. A rugged 650 V SOI-based high-voltage half-bridge IGBT gate driver IC for motor drive applications (United States)

    Hua, Qing; Li, Zehong; Zhang, Bo; Chen, Weizhong; Huang, Xiangjun; Feng, Yuxiang


    This paper proposes a rugged high-voltage N-channel insulated gate bipolar transistor (IGBT) gate driver integrated circuit. The device integrates a high-side and a low-side output stages on a single chip, which is designed specifically for motor drive applications. High-voltage level shift technology enables the high-side stage of this device to operate up to 650 V. The logic inputs are complementary metal oxide semiconductor (CMOS)/transistor transistor logic compatible down to 3.3 V. Undervoltage protection functionality with hysteresis characteristic has also been integrated to enhance the device reliability. The device is fabricated in a 1.0 μm, 650 V high-voltage bipolar CMOS double-diffused metal oxide semiconductor (BCD) on silicon-on-insulator (SOI) process. Deep trench dielectric isolation technology is employed to provide complete electrical isolation with advantages such as reduced parasitic effects, excellent noise immunity and low leakage current. Experimental results show that the isolation voltage of this device can be up to approximately 779 V at 25°C, and the leakage current is only 5 nA at 650 V, which is 15% higher and 67% lower than the conventional ones. In addition, it delivers an excellent thermal stability and needs very low quiescent current and offers a high gate driver capability which is needed to adequately drive IGBTs that have large input capacitances.

  9. Voltage-stabilised elastomers with increased relative permittivity and high electrical breakdown strength by means of phase separating binary copolymer blends of silicone elastomers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Yu, Liyun; Skov, Anne Ladegaard


    Increased electrical breakdown strength and increased dielectric permittivity of silicone-based dielectric elastomers are achieved by means of the addition of so-called voltage-stabilisers prepared from PDMS–PPMS copolymers as well as PDMS–PEG copolymers in order to compensate for the negative...... effect of softness on electrical stability of silicone elastomers. The voltage-stabilised elastomer, incorporating a high-permittivity PDMS–PEG copolymer, possesses increased relative permittivity, high electrical breakdown strength, excellent network integrity and low dielectric loss and paves the way...... towards specialised silicone elastomers for dielectric elastomer transducer products with inherent softness and electrical stability, and thus increased actuation at a given voltage....

  10. Shaft Voltage and Life of Bearing electric-erosion for the Brushless DC Motor (United States)

    Maetani, Tatsuo; Isomura, Yoshinori; Komiyama, Hiroshi; Morimoto, Shigeo

    This paper describes the life of noise of bearing electro-erosion in the shaft voltage of brushless DC motors. We confirmed that shaft voltage is suppressed to equal to or less than the dielectric breakdown voltage of bearing lubricant in the insulated rotor proposed for suppression of shaft voltage. However, since bearing electro-erosion appears over time along with the deterioration of noise performance, the threshold of the shaft voltage to secure noise performance over long periods of time is necessary. Therefore, the threshold of the shaft voltage that influences the life of noise was obtained in acceleration tests.

  11. Novel dielectric reduces corona breakdown in ac capacitors (United States)

    Loehner, J. L.


    Dielectric system was developed which consists of two layers of 25-gage paper separated by one layer of 50-gage polypropylene to reduce corona breakdown in ac capacitors. System can be used in any alternating current application where constant voltage does not exceed 400 V rms. With a little research it could probably be increased to 700 to 800 V rms.

  12. Dielectric interfaces in DC constructions: space charge and polarization phenomena

    NARCIS (Netherlands)

    Morshuis, P.H.F.; Bodega, R.; Fabiani, D.; Montanari, G.C.; Dissado, L.A; Smit, J.J.


    Interfaces between dielectrics are considered one of the weakest parts of an insulation system but their behavior under electrical stress is not yet completely understood. In particular, when a dc voltage is applied, the electric field distribution at the interface is quite difficult to predict. Thi

  13. Impedance Matching of Tapered Slot Antenna using a Dielectric Transformer (United States)

    Simons, R. N.; Lee, R. Q.


    A new impedance matching technique for tapered slot antennas using a dielectric transformer is presented. The technique is demonstrated by measuring the input impedance, Voltage Standing Wave Ratio (VSWR) and the gain of a Vivaldi antenna (VA). Measured results at Ka-Band frequencies are presented and discussed.

  14. Time domain PD-detection vs. dielectric spectroscopy

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Edin, Hans; Gäfvert, Uno


    A theoretically developed relationship between partial discharges and the response from a system for dielectric spectroscopy was experimentally confirmed. The losses caused by the discharges were highest at test voltages with low frequencies. At 0.1 Hz, tanδ tip-up at discharge inception was very...

  15. Contemporary dielectric materials

    CERN Document Server

    Saravanan, R


    This book deals with experimental results of the physical characterization of several important, dielectric materials of great current interest. The experimental tools used for the analysis of these materials include X-ray diffraction, dielectric measurements, magnetic measurements using a vibrating sample magnetometer, optical measurements using a UV-Visible spectrometer etc.

  16. Dielectric material for dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Moran, P.R.; Podgorsak, E.; Fullerton, G.D.; Fuller, G.E.


    A RITAD dosimeter is described having a dielectric material such as sapphire wherein the efficiency as measured by mean drift distance and trapping efficiency is increased by making use of a dielectric material in which the total active impurity does not exceed 50 ppm and in which any one active impurity does not exceed 10 ppm.

  17. Light in complex dielectrics

    NARCIS (Netherlands)

    Schuurmans, F.J.P.


    In this thesis the properties of light in complex dielectrics are described, with the two general topics of "modification of spontaneous emission" and "Anderson localization of light". The first part focuses on the spontaneous emission rate of an excited atom in a dielectric host with variable refra

  18. Polyamide 66 as a Cryogenic Dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Tuncer, Enis [ORNL; Polyzos, Georgios [ORNL; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Messman, Jamie M [ORNL; Aytug, Tolga [ORNL


    Improvements in superconductor and cryogenic technologies enable novel power apparatus, \\eg, cables, transformers, fault current limiters, generators, \\etc, with better device characteristics than their conventional counterparts. In these applications electrical insulation materials play an important role in system weight, footprint (size), and voltage level. The trend in the electrical insulation material selection has been to adapt or to employ conventional insulation materials to these new systems. However, at low temperatures, thermal contraction and loss of mechanical strength in many materials make them unsuitable for superconducting power applications. In this paper, a widely used commercial material was characterized as a potential cryogenic dielectric. The material is used in ``oven bag'' a heat-resistant polyamide (nylon) used in cooking (produced by Reynolds\\textregistered, Richmond, VA, USA). It is first characterized by Fourier transform infrared and x-ray diffraction techniques and determined to be composed of polyamide 66 (PA66) polymer. Secondly the complex dielectric permittivity and dielectric breakdown strength of the PA66 films are investigated. The dielectric data are then compared with data reported in the literature. A comparison of dielectric strength with a widely used high-temperature superconductor electrical insulation material, polypropylene-laminated paper (PPLP\\texttrademark\\ a product of Sumitomo Electric Industries, Japan), is provided. It is observed that the statistical analysis of the PA66 films yields 1\\% failure probability at $127\\ \\kilo\\volt\\milli\\meter^{-1}$; this value is approximately $46\\ \\kilo\\volt\\milli\\meter^{-1}$ higher than PPLP\\texttrademark. It is concluded that PA66 may be a good candidate for cryogenic applications. Finally, a summary of dielectric properties of some of the commercial tape insulation materials and various polymers is also provided.

  19. Reliable and Low-Voltage Electrowetting on Thin Parylene Films

    NARCIS (Netherlands)

    Dhindsa, M.S.; Kuiper, S.; Kumar, R.; Heikenfeld, J.


    The stability of an electrowetting system is dependent upon the choice of liquids, the dielectric material and the operating voltage.Substantial progress is reported herein on use of 300 nm thick poly-tetrafluoro-para-xylylene) (Parylene HT) films for almost 100° of reliable electrowetting modulat

  20. Adenosine Triphosphate (ATP) Inhibits Voltage-Sensitive Potassium Currents in Isolated Hensen's Cells and Nifedipine Protects Against Noise-Induced Hearing Loss in Guinea Pigs. (United States)

    Ye, Rui; Liu, Jun; Jia, Zhiying; Wang, Hongyang; Wang, YongAn; Sun, Wei; Wu, Xuan; Zhao, Zhifei; Niu, Baolong; Li, Xingqi; Dai, Guanghai; Li, Jianxiong


    BACKGROUND There is increasing evidence that adenosine triphosphate (ATP), a well-known neurotransmitter and neuromodulator in the central nervous system, plays an important role as an extracellular chemical messenger in the cochlea. MATERIAL AND METHODS Using a whole-cell recording technique, we studied the effects of ATP on isolated Hensen's cells, which are supporting cells in the cochlea, to determine if they are involved in the transduction of ions with hair cells. RESULTS ATP (0.1-10 µM) reduced the potassium current (IK+) in the majority of the recorded Hensen's cells (21 out of 25 cells). An inward current was also induced by high concentrations of ATP (100 µM to 10 mM), which was reversibly blocked by 100 µM suramin (a purinergic antagonist) and blocked by nifedipine (an L-type calcium channel blocker). After the cochleas were perfused with artificial perilymph solutions containing nifedipine and exposed to noise, the amplitude increase in the compound action potential (CAP) threshold and the reduction in cochlear microphonics was lower than when they were exposed to noise alone. CONCLUSIONS Our results suggest that ATP can block IK+ channels at a low concentration and induce an inward Ca2+ current at high concentrations, which is reversed by purinergic receptors. Nifedipine may have a partially protective effect on noise-induced hearing loss (NIHL).

  1. Transient Voltage Recorder (United States)

    Medelius, Pedro J. (Inventor); Simpson, Howard J. (Inventor)


    A voltage transient recorder can detect lightning induced transient voltages. The recorder detects a lightning induced transient voltage and adjusts input amplifiers to accurately record transient voltage magnitudes. The recorder stores voltage data from numerous monitored channels, or devices. The data is time stamped and can be output in real time, or stored for later retrieval. The transient recorder, in one embodiment, includes an analog-to-digital converter and a voltage threshold detector. When an input voltage exceeds a pre-determined voltage threshold, the recorder stores the incoming voltage magnitude and time of arrival. The recorder also determines if its input amplifier circuits clip the incoming signal or if the incoming signal is too low. If the input data is clipped or too low, the recorder adjusts the gain of the amplifier circuits to accurately acquire subsequent components of the lightning induced transients.

  2. Dielectric Elastomers for Fluidic and Biomedical Applications (United States)

    McCoul, David James

    Dielectric elastomers have demonstrated tremendous potential as high-strain electromechanical transducers for a myriad of novel applications across all engineering disciplines. Because their soft, viscoelastic mechanical properties are similar to those of living tissues, dielectric elastomers have garnered a strong foothold in a plethora of biomedical and biomimetic applications. Dielectric elastomers consist of a sheet of stretched rubber, or elastomer, coated on both sides with compliant electrode materials; application of a voltage generates an electrostatic pressure that deforms the elastomer. They can function as soft generators, sensors, or actuators, and this last function is the focus of this dissertation. Many design configurations are possible, such as stacks, minimum energy structures, interpenetrating polymer networks, shape memory dielectric elastomers, and others; dielectric elastomers are already being applied to many fields of biomedicine. The first part of the original research presented in this dissertation details a PDMS microfluidic system paired with a dielectric elastomer stack actuator of anisotropically prestrained VHB(TM) 4910 (3M(TM)) and single-walled carbon nanotubes. These electroactive microfluidic devices demonstrated active increases in microchannel width when 3 and 4 kV were applied. Fluorescence microscopy also indicated an accompanying increase in channel depth with actuation. The cross-sectional area strains at 3 and 4 kV were approximately 2.9% and 7.4%, respectively. The device was then interfaced with a syringe pump, and the pressure was measured upstream. Linear pressure-flow plots were developed, which showed decreasing fluidic resistance with actuation, from 0.192 psi/(microL/min) at 0 kV, to 0.160 and 0.157 psi/(microL/min) at 3 and 4 kV, respectively. This corresponds to an ~18% drop in fluidic resistance at 4 kV. Active de-clogging was tested in situ with the device by introducing ~50 microm diameter PDMS microbeads and

  3. System for instrumenting and manipulating apparatuses in high voltage (United States)

    Jordan, Kevin


    A system for energizing, operating and manipulating apparatuses in high voltage systems. The system uses a dielectric gas such as SF.sub.6 as a driving power supply for a pneumatic motor which ultimately charges a battery or other energy storage device. The stored energy can then be used for instrumentation equipment, or to power any electrical equipment, in the high voltage deck. The accompanying method provides for the use of the SF6 system for operating an electrical device in a high-voltage environment.

  4. Ultralow-voltage in-plane-gate indium-tin-oxide thin-film transistors made of P-doped SiO2 dielectrics*%基于P掺杂SiO2为栅介质的超低压侧栅薄膜晶体管*

    Institute of Scientific and Technical Information of China (English)

    朱德明; 门传玲†; 曹敏; 吴国栋


    A new kind of indium-tin-oxide thin-film transistors made of P-doped SiO2 dielectrics in an in-plane-gate structure is fabricated at room temperature. Indium-tin-oxide (ITO) channel and ITO electrodes (gate, source, and drain) can be deposited simultaneously without precise photolithography and alignment process by using only one nickel shadow mask. So the thin film transistors (TFTs) have a lot of advantages, such as the simple device process、low cost etc. Such TFTs exhibit a good performance at an ultralow operation voltage of 1 V, a high field-effect mobility of 18.35 cm2/Vs , a small subthreshold swing of 82 mV/decade, and a large on-off ratio of 1.1 × 106, because of the huge electric-double-layer (EDL) capacitance (8 µF/cm2) between the interface of P-doped SiO2 dielectrics and ITO channel. So the TFTs are very promising for the application of low-power and portable electronic products and sensors in the future.%  在室温下利用等离子体增强化学气相沉积法(PECVD)制备的颗粒膜P掺杂SiO2为栅介质,使用磁控溅射方法利用一步掩模法制备出一种新型结构的侧栅薄膜晶体管.由于侧栅薄膜晶体管具有独特的结构,在射频磁控溅射过程中,仅仅利用一块镍掩模板,无需复杂的光刻步骤,就可同时沉积出氧化铟锡(ITO)源、漏、栅电极和沟道,因此,这种方法极大地简化了制备流程,降低了工艺成本.实验结果表明,在P掺杂SiO2栅介质层与沟道层界面处形成了超大的双电层电容(8µF/cm2),这使得这类晶体管具有超低的工作电压1 V,小的亚阈值摆幅82 mV/dec、高的迁移率18.35 cm2/V·s和大的开关电流比1.1×106.因此,这种P掺杂SiO2双电层超低压薄膜晶体管将有望应用于低能耗便携式电子产品以及新型传感器领域.

  5. Research of Dielectric Breakdown Microfluidic Sampling Chip

    Directory of Open Access Journals (Sweden)

    Feng Jiang


    Full Text Available Microfluidic chip is mainly driven electrically by external electrode and array electrode, but there are certain disadvantages in both of ways, which affect the promotion and application of microfluidic technology. This paper discusses a scheme that uses the conductive solution in a microchannel made by PDMS, replacing electrodes and the way of dielectric breakdown to achieve microfluidic chip driver. It could reduce the driving voltage and simplify the chip production process. To prove the feasibility of this method, we produced a microfluidic chip used in PDMS material with the lithography technology and experimented it. The results showed that using the dielectric breakdown to achieve microfluidic chip driver is feasible, and it has certain application prospect.

  6. A new application area for fullerenes: voltage stabilizers for power cable insulation. (United States)

    Jarvid, Markus; Johansson, Anette; Kroon, Renee; Bjuggren, Jonas M; Wutzel, Harald; Englund, Villgot; Gubanski, Stanislaw; Andersson, Mats R; Müller, Christian


    Fullerenes are shown to be efficient voltage-stabilizers for polyethylene, i.e., additives that increase the dielectric strength of the insulation material. Such compounds are highly sought-after because their use in power-cable insulation may considerably enhance the transmission efficiency of tomorrow's power grids. On a molal basis, fullerenes are the most efficient voltage stabilizers reported to date.

  7. Electrical model of dielectric barrier discharge homogenous and filamentary modes (United States)

    López-Fernandez, J. A.; Peña-Eguiluz, R.; López-Callejas, R.; Mercado-Cabrera, A.; Valencia-Alvarado, R.; Muñoz-Castro, A.; Rodríguez-Méndez, B. G.


    This work proposes an electrical model that combines homogeneous and filamentary modes of an atmospheric pressure dielectric barrier discharge cell. A voltage controlled electric current source has been utilized to implement the power law equation that represents the homogeneous discharge mode, which starts when the gas breakdown voltage is reached. The filamentary mode implies the emergence of electric current conducting channels (microdischarges), to add this phenomenon an RC circuit commutated by an ideal switch has been proposed. The switch activation occurs at a higher voltage level than the gas breakdown voltage because it is necessary to impose a huge electric field that contributes to the appearance of streamers. The model allows the estimation of several electric parameters inside the reactor that cannot be measured. Also, it is possible to appreciate the modes of the DBD depending on the applied voltage magnitude. Finally, it has been recognized a good agreement between simulation outcomes and experimental results.

  8. Plasma response to transient high voltage pulses

    Indian Academy of Sciences (India)

    S Kar; S Mukherjee


    This review reports on plasma response to transient high voltage pulses in a low pressure unmagnetized plasma. Mainly, the experiments are reviewed, when a disc electrode (metallic and dielectric) is biased pulsed negative or positive. The main aim is to review the electron loss in plasmas and particle balance during the negative pulse electrode biasing, when the applied pulse width is less than the ion plasma period. Though the applied pulse width is less than the ion plasma period, ion rarefaction waves are excited. The solitary electron holes are reviewed for positive pulsed bias to the electrode. Also the excitation of waves (solitary electron and ion holes) is reviewed for a metallic electrode covered by a dielectric material. The wave excitation during and after the pulse withdrawal, excitation and propagation characteristics of various electrostatic plasma waves are reviewed here.

  9. Dielectric materials for electrical engineering

    CERN Document Server

    Martinez-Vega, Juan


    Part 1 is particularly concerned with physical properties, electrical ageing and modeling with topics such as the physics of charged dielectric materials, conduction mechanisms, dielectric relaxation, space charge, electric ageing and life end models and dielectric experimental characterization. Part 2 concerns some applications specific to dielectric materials: insulating oils for transformers, electrorheological fluids, electrolytic capacitors, ionic membranes, photovoltaic conversion, dielectric thermal control coatings for geostationary satellites, plastics recycling and piezoelectric poly

  10. Automatic voltage imbalance detector (United States)

    Bobbett, Ronald E.; McCormick, J. Byron; Kerwin, William J.


    A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

  11. Hot plasma dielectric tensor

    NARCIS (Netherlands)

    Westerhof, E.


    The hot plasma dielectric tensor is discussed in its various approximations. Collisionless cyclotron resonant damping and ion/electron Bernstein waves are discussed to exemplify the significance of a kinetic description of plasma waves.

  12. Non-contact current and voltage sensor (United States)

    Carpenter, Gary D; El-Essawy, Wael; Ferreira, Alexandre Peixoto; Keller, Thomas Walter; Rubio, Juan C; Schappert, Michael A


    A detachable current and voltage sensor provides an isolated and convenient device to measure current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing that contains the current and voltage sensors, which may be a ferrite cylinder with a hall effect sensor disposed in a gap along the circumference to measure current, or alternative a winding provided through the cylinder along its axis and a capacitive plate or wire disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.

  13. Novel dielectric elastomer structure of soft robot (United States)

    Li, Chi; Xie, Yuhan; Huang, Xiaoqiang; Liu, Junjie; Jin, Yongbin; Li, Tiefeng


    Inspired from the natural invertebrates like worms and starfish, we propose a novel elastomeric smart structure. The smart structure can function as a soft robot. The soft robot is made from a flexible elastomer as the body and driven by dielectric elastomer as the muscle. Finite element simulations based on nonlinear field theory are conducted to investigate the working condition of the structure, and guide the design of the smart structure. The effects of the prestretch, structural stiffness and voltage on the performance of the smart structure are investigated. This work can guide the design of soft robot.

  14. Fuel Cell/Electrochemical Cell Voltage Monitor (United States)

    Vasquez, Arturo


    A concept has been developed for a new fuel cell individual-cell-voltage monitor that can be directly connected to a multi-cell fuel cell stack for direct substack power provisioning. It can also provide voltage isolation for applications in high-voltage fuel cell stacks. The technology consists of basic modules, each with an 8- to 16-cell input electrical measurement connection port. For each basic module, a power input connection would be provided for direct connection to a sub-stack of fuel cells in series within the larger stack. This power connection would allow for module power to be available in the range of 9-15 volts DC. The relatively low voltage differences that the module would encounter from the input electrical measurement connection port, coupled with the fact that the module's operating power is supplied by the same substack voltage input (and so will be at similar voltage), provides for elimination of high-commonmode voltage issues within each module. Within each module, there would be options for analog-to-digital conversion and data transfer schemes. Each module would also include a data-output/communication port. Each of these ports would be required to be either non-electrical (e.g., optically isolated) or electrically isolated. This is necessary to account for the fact that the plurality of modules attached to the stack will normally be at a range of voltages approaching the full range of the fuel cell stack operating voltages. A communications/ data bus could interface with the several basic modules. Options have been identified for command inputs from the spacecraft vehicle controller, and for output-status/data feeds to the vehicle.

  15. Mixed voltage VLSI design (United States)

    Panwar, Ramesh; Rennels, David; Alkalaj, Leon


    A technique for minimizing the power dissipated in a Very Large Scale Integration (VLSI) chip by lowering the operating voltage without any significant penalty in the chip throughput even though low voltage operation results in slower circuits. Since the overall throughput of a VLSI chip depends on the speed of the critical path(s) in the chip, it may be possible to sustain the throughput rates attained at higher voltages by operating the circuits in the critical path(s) with a high voltage while operating the other circuits with a lower voltage to minimize the power dissipation. The interface between the gates which operate at different voltages is crucial for low power dissipation since the interface may possibly have high static current dissipation thus negating the gains of the low voltage operation. The design of a voltage level translator which does the interface between the low voltage and high voltage circuits without any significant static dissipation is presented. Then, the results of the mixed voltage design using a greedy algorithm on three chips for various operating voltages are presented.

  16. Nonlinear Dielectric Response of Water Treed XLPE Cable Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Hvidsten, Sverre


    Condition assessment of XLPE power cables is becoming increasingly important for the utilities, due to a large number of old cables in service with high probability of failure caused by water tree degradation. The commercial available techniques are generally based upon measurements of the dielectric response, either by time (polarisation/depolarisation current or return voltage) or frequency domain measurements. Recently it has been found that a high number of water trees in XLPE insulated cables causes the dielectric response to increase more than linearly with increasing test voltage. This nonlinear feature of water tree degraded XLPE insulation has been suggested to be of a great importance, both for diagnostic purposes, and for fundamental understanding of the water tree phenomenon itself. The main purpose of this thesis have been to study the nonlinear feature of the dielectric response measured on watertreed XLPE insulation. This has been performed by dielectric response measurements in both time and frequency domain, numerical calculations of losses of simplified water tree models, and fmally water content and water permeation measurements on single water trees. The dielectric response measurements were performed on service aged cable samples and laboratory aged Rogowski type objects. The main reason for performing laboratory ageing was to facilitate diagnostic testing as a function of ageing time of samples containing mainly vented water trees. A new method, based upon inserting NaC1 particles at the interface between the upper semiconductive screen and the insulation, was found to successfully enhance initiation and growth of vented water trees. AC breakdown strength testing show that it is the vented water trees that reduce the breakdown level of both the laboratory aged test objects and service aged cable samples. Vented water treeing was found to cause the dielectric response to become nonlinear at a relatively low voltage level. However, the measured

  17. Dielectric spectroscopy in agrophysics (United States)

    Skierucha, W.; Wilczek, A.; Szypłowska, A.


    The paper presents scientific foundation and some examples of agrophysical applications of dielectric spectroscopy techniques. The aim of agrophysics is to apply physical methods and techniques for studies of materials and processes which occur in agriculture. Dielectric spectroscopy, which describes the dielectric properties of a sample as a function of frequency, may be successfully used for examinations of properties of various materials. Possible test materials may include agrophysical objects such as soil, fruit, vegetables, intermediate and final products of the food industry, grain, oils, etc. Dielectric spectroscopy techniques enable non-destructive and non-invasive measurements of the agricultural materials, therefore providing tools for rapid evaluation of their water content and quality. There is a limited number of research in the field of dielectric spectroscopy of agricultural objects, which is caused by the relatively high cost of the respective measurement equipment. With the fast development of modern technology, especially in high frequency applications, dielectric spectroscopy has great potential of expansion in agrophysics, both in cognitive and utilitarian aspects.

  18. The electrical characteristics of the dielectric barrier discharges

    Energy Technology Data Exchange (ETDEWEB)

    Yehia, Ashraf, E-mail: [Department of Physics, College of Science and Humanitarian Studies at Alkharj, Prince Sattam bin Abdulaziz University, P.O. Box 83, Alkharj 11942 (Saudi Arabia); Department of Physics, Faculty of Science, Assiut University, Assiut 71516 (Egypt)


    The electrical characteristics of the dielectric barrier discharges have been studied in this paper under different operating conditions. The dielectric barrier discharges were formed inside two reactors composed of electrodes in the shape of two parallel plates. The dielectric layers inside these reactors were pasted on the surface of one electrode only in the first reactor and on the surfaces of the two electrodes in the second reactor. The reactor under study has been fed by atmospheric air that flowed inside it with a constant rate at the normal temperature and pressure, in parallel with applying a sinusoidal ac voltage between the electrodes of the reactor. The amount of the electric charge that flows from the reactors to the external circuit has been studied experimentally versus the ac peak voltage applied to them. An analytical model has been obtained for calculating the electrical characteristics of the dielectric barrier discharges that were formed inside the reactors during a complete cycle of the ac voltage. The results that were calculated by using this model have agreed well with the experimental results under the different operating conditions.

  19. Regular structures in 5CB liquid crystals under the joint action of ac and dc voltages (United States)

    Aguirre, Luis E.; Anoardo, Esteban; Éber, Nándor; Buka, Ágnes


    A nematic liquid crystal with high, positive dielectric anisotropy (5CB) has been studied under the influence of the combined action of a dc and an ac electric field. Broad frequency, voltage, and cell thickness ranges were considered. Pattern morphologies were identified; the thresholds and critical wave numbers were measured and analyzed as a function of frequency, dc-to-ac voltage ratio, and thickness. The current-voltage characteristics were simultaneously detected.

  20. Aspects regarding the Calculation of the Dielectric Loss Angle Tangent between the Windings of a Rated 40 MVA Transformer

    Directory of Open Access Journals (Sweden)

    Cristinel Popescu


    Full Text Available The paper aims to identify how to determine the dielectric loss angle tangent of the electric transformers from the transformer stations. Autors of the paper managed a case study on the dielectric established between high respectively medium voltage windings of an electrical rated 40 MVA transformer.

  1. History of high-voltage ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Singer, E.

    In principle, the feldspar porcelain used for making tableware way back in the 18th century already would have been good enough for electrical purposes, especially for making high-voltage insulators. Thus, further advances in that sector were made for reasons of economy and better process engineering. This would include things like improving the material's green workability. Then, in 1918, Gilchrist and Klinefelter called attention to property changes in the raw materials triangle kaolinquartz-feldspar. Additional glass matrix increases the finished material's dielectric strength, while a larger share of kaolin improves its heat resistance, and a mixture of quartz and feldspar adds more strength.

  2. General digital microfluidic platform manipulating dielectric and conductive droplets by dielectrophoresis and electrowetting. (United States)

    Fan, Shih-Kang; Hsieh, Tsung-Han; Lin, Di-Yu


    A general digital (droplet-based) microfluidic platform based on the study of dielectric droplet manipulation by dielectrophoresis (DEP) and the integration of DEP and electrowetting-on-dielectric (EWOD) is reported. Transporting, splitting, and merging dielectric droplets are achieved by DEP in a parallel-plate device, which expands the fluids of digital microfluidics from merely being conductive and aqueous to being non-conductive. In this work, decane, hexadecane, and silicone oil droplets were successfully transported in a 150 microm-high gap between two parallel plates by applying a DC voltage above threshold voltages. Non-volatile silicone oil droplets with viscosities of 20 and 50 cSt were studied in more detail in parallel-plate geometries with spacings of 75 microm, 150 microm, and 225 microm. The threshold voltages and the required driving voltages to achieve droplet velocities up to 4 mm/s in the different circumstances were measured. By adding a dielectric layer on the driving electrodes of the tested parallel-plate device, a general digital microfluidic platform capable of manipulating both dielectric and conductive droplets was demonstrated. DEP and EWOD, selectively generated by applying different signals on the same dielectric-covered electrodes, were used to drive silicone oil and water droplets, respectively. Concurrent transporting silicone oil and water droplets along an electrode loop, merging water and oil droplets, and transporting and separating the merged water-in-oil droplet were performed.

  3. Dielectric barrier discharge plasma actuator for flow control (United States)

    Opaits, Dmitry Florievich

    Electrohydrodynamic (EHD) and magnetohydrodynamic phenomena are being widely studied for aerodynamic applications. The major effects of these phenomena are heating of the gas, body force generation, and enthalpy addition or extraction, [1, 2, 3]. In particular, asymmetric dielectric barrier discharge (DBD) plasma actuators are known to be effective EHD device in aerodynamic control, [4, 5]. Experiments have demonstrated their effectiveness in separation control, acoustic noise reduction, and other aeronautic applications. In contrast to conventional DBD actuators driven by sinusoidal voltages, we proposed and used a voltage profile consisting of nanosecond pulses superimposed on dc bias voltage. This produces what is essentially a non-self-sustained discharge: the plasma is generated by repetitive short pulses, and the pushing of the gas occurs primarily due to the bias voltage. The advantage of this non-self-sustained discharge is that the parameters of ionizing pulses and the driving bias voltage can be varied independently, which adds flexibility to control and optimization of the actuators performance. Experimental studies were conducted of a flow induced in a quiescent room air by a single DBD actuator. A new approach for non-intrusive diagnostics of plasma actuator induced flows in quiescent gas was proposed, consisting of three elements coupled together: the Schlieren technique, burst mode of plasma actuator operation, and 2-D numerical fluid modeling. During the experiments, it was found that DBD performance is severely limited by surface charge accumulation on the dielectric. Several ways to mitigate the surface charge were found: using a reversing DC bias potential, three-electrode configuration, slightly conductive dielectrics, and semi conductive coatings. Force balance measurements proved the effectiveness of the suggested configurations and advantages of the new voltage profile (pulses+bias) over the traditional sinusoidal one at relatively low

  4. Programmable high voltage power supply with regulation confined to the high voltage section (United States)

    Castell, Karen D. (Inventor); Ruitberg, Arthur P. (Inventor)


    A high voltage power supply in a dc-dc converter configuration includes a pre-regulator which filters and regulates the dc input and drives an oscillator which applies, in turn, a low voltage ac signal to the low side of a step-up high voltage transformer. The high voltage side of the transformer drives a voltage multiplier which provides a stepped up dc voltage to an output filter. The output voltage is sensed by a feedback network which then controls a regulator. Both the input and output of the regulator are on the high voltage side, avoiding isolation problems. The regulator furnishes a portion of the drive to the voltage multiplier, avoiding having a regulator in series with the load with its attendant, relatively high power losses. This power supply is highly regulated, has low power consumption, a low parts count and may be manufactured at low cost. The power supply has a programmability feature that allows for the selection of a large range of output voltages.

  5. A single dielectric nanolaser (United States)

    Huang, Tsung-Yu; Yen, Ta-Jen


    To conquer Ohmic losses from metal and enhance pump absorption efficiency of a nanolaser based on surface plasmon polariton, we theoretically calculate the first magnetic and electric scattering coefficient of a dielectric sphere under a plane wave excitation with a dielectric constant of around 12. From this calculation, we could retrieve both negative effective permittivity and permeability of the sphere simultaneously at frequencies around 153 THz in the aids of Lewin's theory and the power distribution clearly demonstrate the expected negative Goos-Hänchen effect, which usually occurred in a negative refractive waveguide, thus creating two energy vortices to trap incident energy and then promoting the pump absorption efficiency. Meanwhile, a magnetic lasing mode at 167.3 THz is demonstrated and reveals a magnetic dipole resonance mode and a circulating energy flow within the dielectric sphere, providing a possible stopped light feedback mechanism to enable the all-dielectric nanolaser. More importantly, the corresponding mode volume is reduced to 0.01λ3 and a gain threshold of 5.1×103 is obtained. To validate our design of all-dielectric nanolaser, we employ finite-difference-time-domain simulation software to examine the behavior of the nanolaser. From simulation, we could obtain a pinned-down population inversion of 0.001 and a lasing peak at around 166.5 THz, which is very consistent with the prediction of Mie theory. Finally, according to Mie theory, we can regard the all-dielectric nanolaser as the excitation of material polariton and thus could make an analogue between lasing modes of the dielectric and metallic nanoparticles.

  6. Mismatch of dielectric constants at the interface of nanometer metal-oxide-semiconductor devices with high- gate dielectric impacts on the inversion charge density

    Indian Academy of Sciences (India)

    Ling-Feng Mao


    The comparison of the inversion electron density between a nanometer metal-oxidesemiconductor (MOS) device with high- gate dielectric and a SiO2 MOS device with the same equivalent oxide thickness has been discussed. A fully self-consistent solution of the coupled Schrödinger–Poisson equations demonstrates that a larger dielectric-constant mismatch between the gate dielectric and silicon substrate can reduce electron density in the channel of a MOS device under inversion bias. Such a reduction in inversion electron density of the channel will increase with increase in gate voltage. A reduction in the charge density implies a reduction in the inversion electron density in the channel of a MOS device. It also implies that a larger dielectric constant of the gate dielectric might result in a reduction in the source–drain current and the gate leakage current.

  7. The jump-into-contact effect in biased AFM probes on dielectric films and its application to quantify the dielectric permittivity of thin layers. (United States)

    Revilla, Reynier I


    The jump-into-contact (JIC) phenomenon in biased atomic force microscopy (AFM) probes on dielectric films is studied. The influence of the film thickness on the position at which the AFM tip collapses irreversibly into the sample surface was theoretically analyzed using a widely accepted analytical expression of the probe-sample electrostatic interaction force. It was demonstrated that for relatively high values of voltage (V > 10-20 V) applied between the probe and the substrate the cantilever deflection at the JIC is independent of the dielectric film thickness for thin-ultrathin layers (h film thickness. Based on this effect an empirical model was formulated to estimate the dielectric permittivity of thin/ultrathin dielectric films using the jump-into-contact distance. The procedure was successfully applied on thin PVD-SiO2 films, obtaining good agreement with a dielectric constant value previously reported for the same material.

  8. Experimental study on the dielectric properties of polyacrylate dielectric elastomer (United States)

    Qiang, Junhua; Chen, Hualing; Li, Bo


    The dielectric constant of elastomeric dielectric material is an essential physical parameter, whose value may affect the electromechanical deformation of a dielectric elastomer actuator. Since the dielectric constant is influenced by several external factors as reported before, and no certain value has been confirmed to our knowledge, in the present paper, on the basis of systematical comparison of recent past literature, we conducted extensive works on the measurement of dielectric properties of VHB films, involving five influencing factors: prestretch (both equal and unequal biaxial), electrical frequency, electrode material, stress relaxation time and temperature. Experimental results directly show that the dielectric response changes according to these factors, based on which we investigate the significance of each factor, especially the interaction of two external conditions on the dielectric constant of deformable dielectric, by presenting a physical picture of the mechanism of polarization.

  9. Modeling and control of a dielectric elastomer actuator (United States)

    Gupta, Ujjaval; Gu, Guo-Ying; Zhu, Jian


    The emerging field of soft robotics offers the prospect of applying soft actuators as artificial muscles in the robots, replacing traditional actuators based on hard materials, such as electric motors, piezoceramic actuators, etc. Dielectric elastomers are one class of soft actuators, which can deform in response to voltage and can resemble biological muscles in the aspects of large deformation, high energy density and fast response. Recent research into dielectric elastomers has mainly focused on issues regarding mechanics, physics, material designs and mechanical designs, whereas less importance is given to the control of these soft actuators. Strong nonlinearities due to large deformation and electromechanical coupling make control of the dielectric elastomer actuators challenging. This paper investigates feed-forward control of a dielectric elastomer actuator by using a nonlinear dynamic model. The material and physical parameters in the model are identified by quasi-static and dynamic experiments. A feed-forward controller is developed based on this nonlinear dynamic model. Experimental evidence shows that this controller can control the soft actuator to track the desired trajectories effectively. The present study confirms that dielectric elastomer actuators are capable of being precisely controlled with the nonlinear dynamic model despite the presence of material nonlinearity and electromechanical coupling. It is expected that the reported results can promote the applications of dielectric elastomer actuators to soft robots or biomimetic robots.

  10. Evaluation of Dielectric-Barrier-Discharge Actuator Substrate Materials (United States)

    Wilkinson, Stephen P.; Siochi, Emilie J.; Sauti, Godfrey; Xu, Tian-Bing; Meador, Mary Ann; Guo, Haiquan


    A key, enabling element of a dielectric barrier discharge (DBD) actuator is the dielectric substrate material. While various investigators have studied the performance of different homogeneous materials, most often in the context of related DBD experiments, fundamental studies focused solely on the dielectric materials have received less attention. The purpose of this study was to conduct an experimental assessment of the body-force-generating performance of a wide range of dielectric materials in search of opportunities to improve DBD actuator performance. Materials studied included commonly available plastics and glasses as well as a custom-fabricated polyimide aerogel. Diagnostics included static induced thrust, electrical circuit parameters for 2D surface discharges and 1D volume discharges, and dielectric material properties. Lumped-parameter circuit simulations for the 1D case were conducted showing good correspondence to experimental data provided that stray capacitances are included. The effect of atmospheric humidity on DBD performance was studied showing a large influence on thrust. The main conclusion is that for homogeneous, dielectric materials at forcing voltages less than that required for streamer formation, the material chemical composition appears to have no effect on body force generation when actuator impedance is properly accounted for.

  11. Thickness and dielectric constant determination of thin dielectric layers

    NARCIS (Netherlands)

    Bruijn, de Helene E.; Minor, Marcel; Kooyman, Rob P.H.; Greve, Jan


    We derive a method for the determination of the dielectric constant and thickness of a thin dielectric layer, deposited on top of a thick dielectric layer which is in turn present on a metal film. Reflection of p- and s-polarized light from the metal layer yields minima for certain angles of inciden

  12. Technological Aspects: High Voltage

    CERN Document Server

    Faircloth, D C


    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

  13. Controlling birefringence in dielectrics (United States)

    Danner, Aaron J.; Tyc, Tomáš; Leonhardt, Ulf


    Birefringence, from the very essence of the word itself, refers to the splitting of light rays into two parts. In natural birefringent materials, this splitting is a beautiful phenomenon, resulting in the perception of a double image. In optical metamaterials, birefringence is often an unwanted side effect of forcing a device designed through transformation optics to operate in dielectrics. One polarization is usually implemented in dielectrics, and the other is sacrificed. Here we show, with techniques beyond transformation optics, that this need not be the case, that both polarizations can be controlled to perform useful tasks in dielectrics, and that rays, at all incident angles, can even follow different trajectories through a device and emerge together as if the birefringence did not exist at all. A number of examples are shown, including a combination Maxwell fisheye/Luneburg lens that performs a useful task and is achievable with current fabrication materials.

  14. Dielectric assist accelerating structure (United States)

    Satoh, D.; Yoshida, M.; Hayashizaki, N.


    A higher-order TM02 n mode accelerating structure is proposed based on a novel concept of dielectric loaded rf cavities. This accelerating structure consists of ultralow-loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure. Unlike conventional dielectric loaded accelerating structures, most of the rf power is stored in the vacuum space near the beam axis, leading to a significant reduction of the wall loss, much lower than that of conventional normal-conducting linac structures. This allows us to realize an extremely high quality factor and a very high shunt impedance at room temperature. A simulation of a 5 cell prototype design with an existing alumina ceramic indicates an unloaded quality factor of the accelerating mode over 120 000 and a shunt impedance exceeding 650 M Ω /m at room temperature.

  15. Dielectrically Loaded Biconical Antennas (United States)

    Nusseibeh, Fouad Ahmed


    Biconical antennas are of great interest to those who deal with broadband applications including the transmission/reception of pulses. In particular, wide-angle conical antennas are an attractive choice in many applications including Electronic Support Measures (ESM) and the measurements of transient surface currents and charge densities on aircraft. Dielectric loading in the interior region of a conical antenna can be used to reduce the size of the antenna especially at low frequencies and/or for structural strength. Therefore, having an analytical solution for the input impedance and the frequency response is very helpful in optimizing the design and understanding the behavior of the antenna. From the quasi-analytical solution for the input impedance and the electric field of a wide-angle conical antenna, it can be seen that the dielectric loading in the antenna region improves the input impedance at low frequencies, but increases the number of resonance points and the magnitude of these peaks. When an inhomogeneous dielectric load is used, the magnitude of the resonance peaks is decreased (depending on the way the load is distributed), improving the input impedance of the antenna significantly. Introducing a dielectric load in the interior region of an electrically short receiving cone makes the antenna behave as an electrically longer antenna. However, this is not true for the case for electrical1y long antennas. For the case of pulse transmission, the dielectric load affects only the amplitude. Of course, if the dielectric fills the whole space, both transmitting and receiving antennas behave as electrically longer antennas.

  16. Stress-dependent voltage offsets from polymer insulators used in rock mechanics and material testing (United States)

    Carlson, G. G.; Dahlgren, R.; Vanderbilt, V. C.; Johnston, M. J.; Dunson, C.; Gray, A.; Freund, F.


    Dielectric insulators are used in a variety of laboratory settings when performing experiments in rock mechanics, petrology, and electromagnetic studies of rocks in the fields of geophysics, material science, and civil engineering. These components may be used to electrically isolate geological samples from the experimental equipment, to perform a mechanical compliance function between brittle samples and the loading equipment, to match ultrasonic transducers, or perform other functions. In many experimental configurations the insulators bear the full brunt of force applied to the sample but do not need to withstand high voltages, therefore the insulators are often thin sheets of mechanically tough polymers. From an instrument perspective, transduction from various types of mechanical perturbation has been qualitatively compared for a number of polymers [1, 2] and these error sources are readily apparent during high-impedance measurements if not mitigated. However even when following best practices, a force-dependent voltage signal still remains and its behavior is explored in this presentation. In this experiment two thin sheets (0.25 mm) of high-density polyethylene (HDPE) were set up in a stack, held alternately between three aluminum bars; this stack was placed on the platen of a 60T capacity hydraulic testing machine. The surface area, A, over which the force is applied to the PE sheets in this sandwich is roughly 40 square cm, each sheet forming a parallel-plate capacitor having roughly 320 pF [3], assuming the relative dielectric permittivity of PE is ~2.3. The outer two aluminum bars were connected to the LO input of the electrometer and the central aluminum bar was connected to the HI input of a Keithley model 617 electrometer. Once the stack is mechanically well-seated with no air gaps, the voltage offset is observed to be a linear function of the baseline voltage for a given change in applied force. For a periodically applied force of 66.7 kN the voltage

  17. Stress-Dependent Voltage Offsets From Polymer Insulators Used in Rock Mechanics and Material Testing (United States)

    Carlson, G. G.; Dahlgren, Robert; Gray, Amber; Vanderbilt, V. C.; Freund, F.; Johnston, M. J.; Dunson, C.


    Dielectric insulators are used in a variety of laboratory settings when performing experiments in rock mechanics, petrology, and electromagnetic studies of rocks in the fields of geophysics,material science, and civil engineering. These components may be used to electrically isolate geological samples from the experimental equipment, to perform a mechanical compliance function between brittle samples and the loading equipment, to match ultrasonic transducers, or perform other functions. In manyexperimental configurations the insulators bear the full brunt of force applied to the sample but do not need to withstand high voltages, therefore the insulators are often thin sheets of mechanically tough polymers. From an instrument perspective, transduction from various types of mechanical perturbation has beenqualitatively compared for a number of polymers [1, 2] and these error sources are readily apparent duringhigh-impedance measurements if not mitigated. However even when following best practices, a force dependent voltage signal still remains and its behavior is explored in this presentation. In this experimenttwo thin sheets (0.25 mm) of high-density polyethylene (HDPE) were set up in a stack, held alternatelybetween three aluminum bars; this stack was placed on the platen of a 60T capacity hydraulic testingmachine. The surface area, A, over which the force is applied to the PE sheets in this sandwich is roughly 40 square cm, each sheet forming a parallel-plate capacitor having roughly 320 pF [3], assuming therelative dielectric permittivity of PE is approximately 2.3. The outer two aluminum bars were connected to the LO input ofthe electrometer and the central aluminum bar was connected to the HI input of a Keithley model 617 electrometer. Once the stack is mechanically well-seated with no air gaps, the voltage offset is observed tobe a linear function of the baseline voltage for a given change in applied force. For a periodically appliedforce of 66.7 kN the

  18. Alternating current breakdown voltage of ice electret (United States)

    Oshika, Y.; Tsuchiya, Y.; Okumura, T.; Muramoto, Y.


    Ice has low environmental impact. Our research objectives are to study the availability of ice as a dielectric insulating material at cryogenic temperatures. We focus on ferroelectric ice (iceXI) at cryogenic temperatures. The properties of iceXI, including its formation, are not clear. We attempted to obtain the polarized ice that was similar to iceXI under the applied voltage and cooling to 77 K. The polarized ice have a wide range of engineering applications as electronic materials at cryogenic temperatures. This polarized ice is called ice electret. The structural difference between ice electret and normal ice is only the positions of protons. The effects of the proton arrangement on the breakdown voltage of ice electret were shown because electrical properties are influenced by the structure of ice. We observed an alternating current (ac) breakdown voltage of ice electret and normal ice at 77 K. The mean and minimum ac breakdown voltage values of ice electret were higher than those of normal ice. We considered that the electrically weak part of the normal ice was improved by applied a direct electric field.

  19. Voltage-controlled nanoscale reconfigurable magnonic crystal (United States)

    Wang, Qi; Chumak, Andrii V.; Jin, Lichuan; Zhang, Huaiwu; Hillebrands, Burkard; Zhong, Zhiyong


    A nanoscale reconfigurable magnonic crystal is designed using voltage-controlled perpendicular magnetic anisotropy (PMA) in ferromagnetic-dielectric heterostructures. A periodic array of gate metallic strips is placed on top of a MgO/Co structure in order to apply a periodic electric field and to modify the PMA in Co. It is numerically demonstrated that the introduction of PMA, which can be realized experimentally via applying a voltage, modifies the spin-wave propagation and leads to the formation of band gaps in the spin-wave spectrum. The band gaps can be controlled, i.e., it is possible to switch band gaps on and off within a few tens of nanoseconds. The width and the center frequency of the band gaps are defined by the applied voltage. Finally, it is shown that the introduction of PMA to selected, rather than to all gate strips allows for a predefined modification of the band-gap spectra. The proposed voltage-controlled reconfigurable magnonic crystal opens a way to low power consumption magnonic applications.

  20. Characterization of dielectric constant of solid materials (Leather belt at X-Band

    Directory of Open Access Journals (Sweden)

    Ambika Singh


    Full Text Available This paper discusses the experimental measurement technique for dielectric constant (i.e.permittivity of leather belt at X-band. This measurement play selection of dielectric constant for antenna substrate. This leather can be used as flexible substrate of wearable microstrip antenna. This measurement system consist of solid state klystron power supply, isolator, VSWR meter, frequency meter, solid dielectric cell (XC-501. This data may be interested in flexibility wearable microstrip antenna studies.

  1. Stray voltage mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Jamali, B.; Piercy, R.; Dick, P. [Kinetrics Inc., Toronto, ON (Canada). Transmission and Distribution Technologies


    This report discussed issues related to farm stray voltage and evaluated mitigation strategies and costs for limiting voltage to farms. A 3-phase, 3-wire system with no neutral ground was used throughout North America before the 1930s. Transformers were connected phase to phase without any electrical connection between the primary and secondary sides of the transformers. Distribution voltage levels were then increased and multi-grounded neutral wires were added. The earth now forms a parallel return path for the neutral current that allows part of the neutral current to flow continuously through the earth. The arrangement is responsible for causing stray voltage. Stray voltage causes uneven milk production, increased incidences of mastitis, and can create a reluctance to drink water amongst cows when stray voltages are present. Off-farm sources of stray voltage include phase unbalances, undersized neutral wire, and high resistance splices on the neutral wire. Mitigation strategies for reducing stray voltage include phase balancing; conversion from single to 3-phase; increasing distribution voltage levels, and changing pole configurations. 22 refs., 5 tabs., 13 figs.

  2. High voltage engineering

    CERN Document Server

    Rizk, Farouk AM


    Inspired by a new revival of worldwide interest in extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission, High Voltage Engineering merges the latest research with the extensive experience of the best in the field to deliver a comprehensive treatment of electrical insulation systems for the next generation of utility engineers and electric power professionals. The book offers extensive coverage of the physical basis of high-voltage engineering, from insulation stress and strength to lightning attachment and protection and beyond. Presenting information critical to the design, selec

  3. High voltage test techniques

    CERN Document Server

    Kind, Dieter


    The second edition of High Voltage Test Techniques has been completely revised. The present revision takes into account the latest international developments in High Voltage and Measurement technology, making it an essential reference for engineers in the testing field.High Voltage Technology belongs to the traditional area of Electrical Engineering. However, this is not to say that the area has stood still. New insulating materials, computing methods and voltage levels repeatedly pose new problems or open up methods of solution; electromagnetic compatibility (EMC) or components and systems al

  4. Mitigation of Unbalanced Voltage Sags and Voltage Unbalance in CIGRE Low Voltage Distribution Network


    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar; Cecati, Carlo


    Any problem with voltage in a power network is undesirable as it aggravates the quality of the power. Power electronic devices such as Voltage Source Converter (VSC) based Static Synchronous Compensator (STATCOM) etc. can be used to mitigate the voltage problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate unbalanced voltage sags and voltage unbalance in the CIGRE Low Voltage (LV) test network and net-works like this. The voltage unbala...

  5. Absorption in dielectric models

    CERN Document Server

    Churchill, R J


    We develop a classical microscopic model of a dielectric. The model features nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, giving broadband absorption of electromagnetic radiation without the addition of damping terms in the dynamics. The effective permittivity is calculated using a perturbative iteration method and is found to have the form associated with real dielectrics. Spatial dispersion is naturally included in the model and we also calculate the wavevector dependence of the permittivity.

  6. Optics of dielectric microstructures

    DEFF Research Database (Denmark)

    Søndergaard, Thomas


    microstructures, will be presented in the part I of this thesis consisting of the chapters 2-5. An introductions is given in chapter 2. In part I three methods are presented for calculating spontaneous and classical emission from sources in dielectric microstructures. The first method presented in chapter 3...... near fields and far fields generated by a dipole emitter in finite-sized dielectric disks. A collection of results obtained within the second topic, planar photonic crystal waveguides, are presented in part II of this thesis consisting of the chapters 6-10. Chapter 6 contains a further introduction...

  7. Thermally switchable dielectrics (United States)

    Dirk, Shawn M.; Johnson, Ross S.


    Precursor polymers to conjugated polymers, such as poly(phenylene vinylene), poly(poly(thiophene vinylene), poly(aniline vinylene), and poly(pyrrole vinylene), can be used as thermally switchable capacitor dielectrics that fail at a specific temperature due to the non-conjugated precursor polymer irreversibly switching from an insulator to the conjugated polymer, which serves as a bleed resistor. The precursor polymer is a good dielectric until it reaches a specific temperature determined by the stability of the leaving groups. Conjugation of the polymer backbone at high temperature effectively disables the capacitor, providing a `built-in` safety mechanism for electronic devices.

  8. In situ study on low-k interconnect time-dependent-dielectric-breakdown mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Boon Yeap, Kong, E-mail: [GLOBALFOUNDRIES, Fab8, 400 Stonebreak Rd. Extension, Malta, New York 12020 (United States); Fraunhofer Institute for Ceramic Technologies and Systems, Maria-Reiche-Str. 2, D-01109 Dresden (Germany); Gall, Martin; Liao, Zhongquan; Sander, Christoph; Muehle, Uwe; Zschech, Ehrenfried [Fraunhofer Institute for Ceramic Technologies and Systems, Maria-Reiche-Str. 2, D-01109 Dresden (Germany); Justison, Patrick [GLOBALFOUNDRIES, Fab8, 400 Stonebreak Rd. Extension, Malta, New York 12020 (United States); Aubel, Oliver; Hauschildt, Meike; Beyer, Armand; Vogel, Norman [GLOBALFOUNDRIES Dresden Module One LLC and Co. KG, Wilschdorfer Landstr. 101, D-01109 Dresden (Germany)


    An in situ transmission-electron-microscopy methodology is developed to observe time-dependent dielectric breakdown (TDDB) in an advanced Cu/ultra-low-k interconnect stack. A test structure, namely a “tip-to-tip” structure, was designed to localize the TDDB degradation in small dielectrics regions. A constant voltage is applied at 25 °C to the “tip-to-tip” structure, while structural changes are observed at nanoscale. Cu nanoparticle formation, agglomeration, and migration processes are observed after dielectric breakdown. The Cu nanoparticles are positively charged, since they move in opposite direction to the electron flow. Measurements of ionic current, using the Triangular-Voltage-Stress method, suggest that Cu migration is not possible before dielectric breakdown, unless the Cu/ultra-low-k interconnect stacks are heated to 200 °C and above.

  9. Quantitative statistical analysis of dielectric breakdown in zirconia-based self-assembled nanodielectrics. (United States)

    Schlitz, Ruth A; Ha, Young-geun; Marks, Tobin J; Lauhon, Lincoln J


    Uniformity of the dielectric breakdown voltage distribution for several thicknesses of a zirconia-based self-assembled nanodielectric was characterized using the Weibull distribution. Two regimes of breakdown behavior are observed: self-assembled multilayers >5 nm thick are well described by a single two-parameter Weibull distribution, with β ≈ 11. Multilayers ≤5 nm thick exhibit kinks on the Weibull plot of dielectric breakdown voltage, suggesting that multiple characteristic mechanisms for dielectric breakdown are present. Both the degree of uniformity and the effective dielectric breakdown field are observed to be greater for one layer than for two layers of Zr-SAND, suggesting that this multilayer is more promising for device applications.

  10. Growth kinetics and complex characterization of PECVD SiO x N y dielectric films (United States)

    Pereyaslavtsev, A.; Sokolov, I.


    This paper is devoted to the study of patterns of dielectric film growth depending on the parameters of the plasma chemical deposition process. The study has revealed the influence of the basic reagents’ content on the changes in surface morphology, breakdown voltage and stoichiometry (transition to the intermediate oxidation states of silicon) of dielectric films. Furthermore, an exponential pattern of the change in the films’ growth rate has been registered. When increasing the N/Si ratio, a nonlinear dependence of the change in the dielectric films’ band gap has been recorded. When increasing the SiH4/N2O ratio, a shift of the peak positions of the interband interactions relative to the band gap boundaries has been detected. The dataset on breakdown voltage and band structure suggests a certain optimum of barrier properties of SiO x N y dielectric films at the basic reagents’ ratio close to 0.3-0.4.

  11. Local dielectric permittivity profiles of sapphire/polypropylene interfaces (United States)

    Yu, Liping; Ranjan, V.; Buongiorno Nardelli, M.; Bernholc, J.


    Recently, the need for high-power-density capacitors has stimulated research to develop composite dielectric materials with high-k nanoparticles embedded in a polymer matrix. In these materials, surfaces and interfaces may play an important role in determining the overall dielectric properties. We present first-principles investigations of the dielectric permittivity profiles across slabs and interfaces of sapphire(α-Al2O3)/isotactic-polypropylene(iPP). Our results indicate that the permittivity profile at interface strongly depends on the nanoscale averaging procedure. We propose an averaging model that ensures near-locality of the dielectric function. We find that: (i) the dielectric permittivity approaches the corresponding bulk value just a few atomic layers away from the interface or surface; (ii) the dielectric constant is enhanced at the surfaces of the isolated α-Al2O3 slabs, while no enhancement is observed at the iPP slab surfaces; and (iii) the dielectric transition at the αAl2O3/iPP is mainly confined in the αAl2O3 side.

  12. Exploring dielectric elastomers as actuators for hand tremor suppression (United States)

    Kelley, Christopher R.; Kauffman, Jeffrey L.


    Pathological tremor results in undesired motion of body parts, with the greatest effect typically occurring in the hands. Since common treatment methods are ineffective in some patients or have risks associated with surgery or side effects, researchers are investigating mechanical means of tremor suppression. This work explores the viability of dielectric elastomers as the actuators in a tremor suppression control system. Dielectric elastomers have many properties similar to human muscle, making them a natural fit for integration into the human biomechanical system. This investigation develops a model of the integrated wrist-actuator system to determine actuator parameters that produce the necessary control authority without significantly affecting voluntary motion. Furthermore, this paper develops a control law for the actuator voltage to increase the effective viscous damping of the system. Simulations show excellent theoretical tremor suppression, demonstrating the potential for dielectric elastomers to suppress tremor while maximizing compatibility between the actuator and the human body.

  13. Method of measuring dielectric constant using an oscilloscope (United States)

    Nogi, Yasuyuki; Watanabe, Masayuki; Suzuki, Kiyomitsu; Ohkuma, Yasunori


    A simple relationship determining the dielectric constant of a material inserted in a parallel-plate capacitor is formulated from Gauss's law for a uniform electric field and the continuity condition of electric flux at the boundary of the material. The relationship suggests that the dielectric constant can be determined from the dependence of the charge stored on the capacitor on the thicknesses of the material and the air layer between the plates. A uniform field is created by applying an ac voltage to the plates, which includes a guard ring. The stored charge is estimated by using an oscilloscope to measure the voltage across a resistor inserted between the power supply and the capacitor. The results of the measurement are given for planar materials such as soda-lime glass, Bakelite, acrylic glass, and Teflon with a thickness of 0.5-1 cm.

  14. Thermally grown thin nitride films as a gate dielectric

    CERN Document Server

    Shin, H C; Hwang, T K; Lee, K R


    High-quality very thin films ( <=6 nm) of silicon nitride were thermally grown in ammonia atmosphere with an IR (Infrared) gold image furnace. As-grown nitride film was analyzed using AES(Auger Emission Spectroscopy). Using MIS (Metal-Insulator-Semiconductor) devices, the growth rate was calculated using CV (Capacitance-Voltage) measurements and various electrical characteristics were obtained using CV, IV (Current-Voltage), trapping, time-dependent breakdown, high-field stress, constant current injection stress and dielectric breakdown techniques. These characteristics showed that very thin thermal silicon nitride films can be used as gate dielectrics for future highly scaled-down ULSI (Ultra Large Scale Integrated) devices, especially for EEPROM (Electrically Erasable and Programmable ROM)'s.

  15. Droplets actuating chip based on electrowetting-on-dielectric

    Institute of Scientific and Technical Information of China (English)

    WU Jiangang; YUE Ruifeng; ZENG Xuefeng; LIU Litian


    A droplet-based actuating chip by using the method of electrowetting-on-dielectric (EWOD)was developed to manipulate the microfluidics.Here,the actuation mechanism of the sandwiched-configuration EWOD chips was carefully studied,and the movement of droplets was numerically analyzed by using the computational fluidic software,CFD-ACE+.The fabrication of the chip,including a heavily phosphorus-doped poly-silicon micro-electrode array and a thermally grown SiO2 dielectric layer,was exploited to improve the chip stability and decrease the actuation voltage.In experiments,the transportation of a deionized droplet of about 0.5 μL is successfully achieved in air by applying the low voltage of 45 V.

  16. Asymmetry bistability for a coupled dielectric elastomer minimum energy structure (United States)

    Li, Wen-Bo; Zhang, Wen-Ming; Zou, Hong-Xiang; Peng, Zhi-Ke; Meng, Guang


    In this paper, a novel design of asymmetry bistability for a coupled dielectric elastomer minimum energy structure (DEMES) is presented. The structure can be stable both in the stretched and curved configurations, which are induced by the geometry coupling effect of two DEMESs with perpendicular bending axes. The unique asymmetry bistability and fully flexible compact design of the coupled DEMES can enrich the active morphing modes of the dielectric elastomer actuators. A theoretical model of the system’s strain energy is established to explain the bistability. Furthermore, a prototype is fabricated to verify the conceptual design. The experimental results show that when the applied voltage is below a critical transition one, the structure behaves as a conventional DEMES, once the applied voltage exceeds the critical voltage, the structure could change from the stretched (curved) configuration to the curved (stretched) configuration abruptly and maintain in a new stable configuration when the voltage is removed. A multi-segment structure with the coupled DEMES is also presented and fabricated, and it displays various voltage-actuated morphings. It indicates that the coupled DEMES and the multi-segment structures can be useful for the soft and shape-shifting robots.

  17. Microstructural and dielectric susceptibility effects on predictions of dielectric properties

    Energy Technology Data Exchange (ETDEWEB)

    Ferris, K.F.; Exarhos, G.J. [Pacific Northwest National Lab., Richland, WA (United States); Risser, S.M. [Texas A& M Univ., Commerce, TX (United States)


    In modeling the dielectric properties of inhomogeneous materials, the treatment of the electric field interactions differentiate the usual modeling formalisms (such as the Maxwell-Garnett and Bruggeman effective medium methods) and their accuracy. In this paper, we show that the performance of effective medium methods is dependent upon a number of variables - defect concentration, alignment, and the dielectric constant of the material itself. Using our previously developed finite element model of an inhomogeneous dielectric, we have developed models for a number of dielectric films of varying dielectric constant and microstructures. Alignment of defects parallel to the applied field and the larger defect aspect ratios increase the overall dielectric constant. The extent of these effects is dependent on the dielectric constant of the bulk component.

  18. Planar LTCC transformers for high voltage flyback converters: Part II.

    Energy Technology Data Exchange (ETDEWEB)

    Schofield, Daryl (NASCENTechnology, Inc., Watertown, SD); Schare, Joshua M., Ph.D.; Slama, George (NASCENTechnology, Inc., Watertown, SD); Abel, David (NASCENTechnology, Inc., Watertown, SD)


    This paper is a continuation of the work presented in SAND2007-2591 'Planar LTCC Transformers for High Voltage Flyback Converters'. The designs in that SAND report were all based on a ferrite tape/dielectric paste system originally developed by NASCENTechnoloy, Inc, who collaborated in the design and manufacturing of the planar LTCC flyback converters. The output/volume requirements were targeted to DoD application for hard target/mini fuzing at around 1500 V for reasonable primary peak currents. High voltages could be obtained but with considerable higher current. Work had begun on higher voltage systems and is where this report begins. Limits in material properties and processing capabilities show that the state-of-the-art has limited our practical output voltage from such a small part volume. In other words, the technology is currently limited within the allowable funding and interest.

  19. The transfer voltage standard for calibration outside of a laboratory

    Directory of Open Access Journals (Sweden)

    Urekar Marjan


    Full Text Available The transfer voltage standard is designed for transferring the analog voltage from a calibrator to the process control workstation for multi-electrode electrolysis process in a plating plant. Transfer voltage standard is based on polypropylene capacitors and operational amplifiers with tera-ohm range input resistance needed for capacitor self-discharging effect cancellation. Dielectric absorption effect is described. An instrument for comparison of reference and control voltages is devised, based on precise window comparator. Detailed description of the main task is given, including constraints, theoretical and practical solutions. Procedure for usage of the standard outside of a laboratory conditions is explained. Comparison of expected and realized standard characteristics is given. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-32019

  20. High Voltage Bi-directional Flyback Converter for Capacitive Actuator

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.


    This paper presents a high voltage DC-DC converter topology for bi-directional energy transfer between a low voltage DC source and a high voltage capacitive load. The topology is a bi-directional flyback converter with variable switching frequency control during the charge mode, and constant...... switching frequency control during the discharge mode. The converter is capable of charging the capacitive load from 24 V DC source to 2.5 kV, and discharges it to 0 V. The flyback converter has been analyzed in detail during both charge and discharge modes, by considering all the parasitic elements...... in the converter, including the most dominating parameters of the high voltage transformer viz., self-capacitance and leakage inductance. The specific capacitive load for this converter is a dielectric electro active polymer (DEAP) actuator, which can be used as an effective replacement for conventional actuators...

  1. High-voltage air-core pulse transformers

    Energy Technology Data Exchange (ETDEWEB)

    Rohwein, G. J.


    General types of air core pulse transformers designed for high voltage pulse generation and energy transfer applications are discussed with special emphasis on pulse charging systems which operate up to the multi-megavolt range. The design, operation, dielectric materials, and performance are described. It is concluded that high voltage air core pulse transformers are best suited to applications outside the normal ranges of conventional magnetic core transformers. In general these include charge transfer at high power levels and fast pulse generation with comparatively low energy. When properly designed and constructed, they are capable of delivering high energy transfer efficiency and have demonstrated superior high voltage endurance. The principal disadvantage of high voltage air core transformers is that they are not generally available from commercial sources. Consequently, the potential user must become thoroughly familiar with all aspects of design, fabrication and system application before he can produce a high performance transformer system. (LCL)

  2. Dielectric Waveguide lasers

    NARCIS (Netherlands)

    Pollnau, Markus; Orlovic, V.A.; Pachenko, V.; Scherbakov, I.A.


    Our recent results on planar and channel waveguide fabrication and lasers in the dielectric oxide materials Ti:sapphire and rare-earth-ion-doped potassium yttrium double tungstate (KYW) are reviewed. We have employed waveguide fabrication methods such as liquid phase epitaxy and reactive ion etching

  3. Interfaces: nanometric dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, T J [School of Informatics, University of Wales Bangor, Dean Street, Bangor, Gwynedd, LL70 9PX (United Kingdom)


    The incorporation of nanometric size particles in a matrix to form dielectric composites shows promise of materials (nanodielectrics) with new and improved properties. It is argued that the properties of the interfaces between the particles and the matrix, which will themselves be of nanometric dimensions, will have an increasingly dominant role in determining dielectric performance as the particle size decreases. The forces that determine the electrical and dielectric properties of interfaces are considered, with emphasis on the way in which they might influence composite behaviour. A number of examples are given in which interfaces at the nanometric level exercise both passive and active control over dielectric, optical and conductive properties. Electromechanical properties are also considered, and it is shown that interfaces have important electrostrictive and piezoelectric characteristics. It is demonstrated that the process of poling, namely subjecting macroscopic composite materials to electrical stress and raised temperatures to create piezoelectric materials, can be explained in terms of optimizing the collective response of the nanometric interfaces involved. If the electrical and electromechanical features are coupled to the long-established electrochemical properties, interfaces represent highly versatile active elements with considerable potential in nanotechnology.

  4. Interfaces: nanometric dielectrics (United States)

    Lewis, T. J.


    The incorporation of nanometric size particles in a matrix to form dielectric composites shows promise of materials (nanodielectrics) with new and improved properties. It is argued that the properties of the interfaces between the particles and the matrix, which will themselves be of nanometric dimensions, will have an increasingly dominant role in determining dielectric performance as the particle size decreases. The forces that determine the electrical and dielectric properties of interfaces are considered, with emphasis on the way in which they might influence composite behaviour. A number of examples are given in which interfaces at the nanometric level exercise both passive and active control over dielectric, optical and conductive properties. Electromechanical properties are also considered, and it is shown that interfaces have important electrostrictive and piezoelectric characteristics. It is demonstrated that the process of poling, namely subjecting macroscopic composite materials to electrical stress and raised temperatures to create piezoelectric materials, can be explained in terms of optimizing the collective response of the nanometric interfaces involved. If the electrical and electromechanical features are coupled to the long-established electrochemical properties, interfaces represent highly versatile active elements with considerable potential in nanotechnology.

  5. Dielectric elastomer memory (United States)

    O'Brien, Benjamin M.; McKay, Thomas G.; Xie, Sheng Q.; Calius, Emilio P.; Anderson, Iain A.


    Life shows us that the distribution of intelligence throughout flexible muscular networks is a highly successful solution to a wide range of challenges, for example: human hearts, octopi, or even starfish. Recreating this success in engineered systems requires soft actuator technologies with embedded sensing and intelligence. Dielectric Elastomer Actuator(s) (DEA) are promising due to their large stresses and strains, as well as quiet flexible multimodal operation. Recently dielectric elastomer devices were presented with built in sensor, driver, and logic capability enabled by a new concept called the Dielectric Elastomer Switch(es) (DES). DES use electrode piezoresistivity to control the charge on DEA and enable the distribution of intelligence throughout a DEA device. In this paper we advance the capabilities of DES further to form volatile memory elements. A set reset flip-flop with inverted reset line was developed based on DES and DEA. With a 3200V supply the flip-flop behaved appropriately and demonstrated the creation of dielectric elastomer memory capable of changing state in response to 1 second long set and reset pulses. This memory opens up applications such as oscillator, de-bounce, timing, and sequential logic circuits; all of which could be distributed throughout biomimetic actuator arrays. Future work will include miniaturisation to improve response speed, implementation into more complex circuits, and investigation of longer lasting and more sensitive switching materials.

  6. Breakdown voltage model and structure realization of a thin silicon layer with linear variable doping on a silicon on insulator high voltage device with multiple step field plates

    Institute of Scientific and Technical Information of China (English)

    Qiao Ming; Zhuang Xiang; Wu Li-Juan; Zhang Wen-Tong; Wen Heng-Juan; Zhang Bo; Li Zhao-Ji


    Based on the theoretical and experimental investigation of a thin silicon layer (TSL) with linear variable doping (LVD) and further research on the TSL LVD with a multiple step field plate (MSFP),a breakdown voltage (BV) model is proposed and experimentally verified in this paper.With the two-dimensional Poisson equation of the silicon on insulator (SOI) device,the lateral electric field in drift region of the thin silicon layer is assumed to be constant.For the SOI device with LVD in the thin silicon layer,the dependence of the BV on impurity concentration under the drain is investigated by an enhanced dielectric layer field (ENDIF),from which the reduced surface field (RESURF) condition is deduced.The drain in the centre of the device has a good self-isolation effect but the problem of the high voltage interconnection (HVI) line will become serious.The two step field plates including the source field plate and gate field plate can be adopted to shield the HVI adverse effect on the device.Based on this model,the TSL LVD SOI n-channel lateral double-diffused MOSFET (nLDMOS) with MSFP is realized.The experimental breakdown voltage (BV) and specific on-resistance (Ron,sp) of the TSL LVD SOI device are 694 V and 21.3 Ω.mm2 with a drift region length of 60 μm,buried oxide layer of 3 μm,and silicon layer of 0.15 μm,respectively.

  7. Voltage verification unit (United States)

    Martin, Edward J.


    A voltage verification unit and method for determining the absence of potentially dangerous potentials within a power supply enclosure without Mode 2 work is disclosed. With this device and method, a qualified worker, following a relatively simple protocol that involves a function test (hot, cold, hot) of the voltage verification unit before Lock Out/Tag Out and, and once the Lock Out/Tag Out is completed, testing or "trying" by simply reading a display on the voltage verification unit can be accomplished without exposure of the operator to the interior of the voltage supply enclosure. According to a preferred embodiment, the voltage verification unit includes test leads to allow diagnostics with other meters, without the necessity of accessing potentially dangerous bus bars or the like.

  8. Magnetic field tunable capacitive dielectric:ionic-liquid sandwich composites (United States)

    Wu, Ye; Bhalla, Amar; Guo, Ruyan


    We examined the tunability of the capacitance for GaFeO3-ionic liquid-GaFeO3 composite material by external magnetic and electric field. Up to 1.6 folds of capacitance tunability could be achieved at 957 kHz with voltage 4 V and magnetic field 0.02 T applied. We show that the capacitance enhancement is due to the polarization coupling between dielectric layer and ionic liquid layer.

  9. Energy scavenging strain absorber: application to kinetic dielectric elastomer generator (United States)

    Jean-Mistral, C.; Beaune, M.; Vu-Cong, T.; Sylvestre, A.


    Dielectric elastomer generators (DEGs) are light, compliant, silent energy scavengers. They can easily be incorporated into clothing where they could scavenge energy from the human kinetic movements for biomedical applications. Nevertheless, scavengers based on dielectric elastomers are soft electrostatic generators requiring a high voltage source to polarize them and high external strain, which constitutes the two major disadvantages of these transducers. We propose here a complete structure made up of a strain absorber, a DEG and a simple electronic power circuit. This new structure looks like a patch, can be attached on human's wear and located on the chest, knee, elbow… Our original strain absorber, inspired from a sailing boat winch, is able to heighten the external available strain with a minimal factor of 2. The DEG is made of silicone Danfoss Polypower and it has a total area of 6cm per 2.5cm sustaining a maximal strain of 50% at 1Hz. A complete electromechanical analytical model was developed for the DEG associated to this strain absorber. With a poling voltage of 800V, a scavenged energy of 0.57mJ per cycle is achieved with our complete structure. The performance of the DEG can further be improved by enhancing the imposed strain, by designing a stack structure, by using a dielectric elastomer with high dielectric permittivity.

  10. Dielectric strength test to protection elements for live lines works

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Pinto-Salamanca


    Full Text Available This paper presents the design and assembly of a system of tests of sustained voltage to elements and equipment used in live line maneuvers through tests on gloves and dielectric rods, as these are the first points of contact to ensure safe operations. It means an advance for the creation of a laboratory certified in this type of tests at Universidad Pedagógica y Tecnológica de Colombia (UPTC Faculty of Duitama, considering that currently there are not laboratories that provide this service in Boyacá and Casanare. Dielectric strength tests were performed on personal protection elements and equipment under the parameters of ASTM D120, ASTM F496, ISO 60903, ASTM-F711 and IEEE 978, developing an assembly for testing gloves and dielectric rods with voltage levels up to 15 kV. The results validate the proposed system to outlook of circuit design and implementation, where tests were performed to establish dielectric capacities, in operating under open circuit conditions, with resistive load or short circuit. The compliance with the regulations established under the test sequences of safety parameters for the system and the follow-up to the tests was verified through the use of a management system for the generation of concepts of approval or rejection of the tested elements.

  11. Optimization of dielectric matrix for ZnO nanowire based nanogenerators (United States)

    Kannan, Santhosh; Parmar, Mitesh; Tao, Ran; Ardila, Gustavo; Mouis, Mireille


    This paper reports the role of selection of suitable dielectric layer in nanogenerator (NG) structure and its influence on the output performance. The basic NG structure is a composite material integrating hydrothermally grown vertical piezoelectric zinc oxide (ZnO) nanowires (NWs) into a dielectric matrix. To accomplish this study, three materials - poly methyl methacrylate (PMMA), silicon nitride (Si3N4) and aluminium oxide (Al2O3) are selected, processed and used as matrix dielectric in NGs. Scanning electron microscopy (SEM) analysis shows the well-aligned NWs with a diameter of 200±50 nm and length of 3.5±0.3 μm. This was followed by dielectric material deposition as a matrix material. After fabricating NG devices, the output generated voltage under manual and automatic bending were recorded, observed and analyzed for the selection of the best dielectric material to obtain an optimum output. The maximum peak-to-peak open-circuit voltage output for PMMA, Si3N4 and Al2O3 under manual bending was recorded as approximately 880 mV, 1.2 V and 2.1 V respectively. These preliminary results confirm the predicted effect of using more rigid dielectrics as matrix material for the NGs. The generated voltage is increased by about 70% using Si3N4 or Al2O3, instead of a less rigid material as PMMA.

  12. Energy harvesting by dielectric elastomer generator and self-priming circuit: verification by radio transmission (United States)

    Ikegame, Toru; Takagi, Kentaro; Ito, Takamasa; Kojima, Hiroki; Yoshikawa, Hitoshi


    This paper discusses energy harvesting and its application using dielectric elastomer and self-priming circuit. With the self-priming circuit attached to the dielectric elastomer, the generated voltage increases exponentially according to the variation of the capacitance caused by applied deformation to the elastomer. Two-stage self-priming circuit is selected for optimal harvesting. The self-priming harvesting technique is able to increase the voltage of the dielectric elastomer from a few volts to kV order, however in this paper the generated voltage is limited up to 1kV in order to avoid the destruction of the dielectric elastomer. The ability of energy harvesting using dielectric elastomer and self-priming circuit is confirmed by both numerical simulation and experiments. In the experiment, the dielectric elastomer is deformed by an electric motor, and the harvested energy is stored to a charging capacitor through Zener diodes. A low-power microcomputer which has a radio transmitter is connected to the charging capacitor for the application example. The experimental results show that the temperature data can be transmitted only by the harvested energy. In addition, the efficiency of the energy harvesting is calculated by comparing the generated power with the charged power.

  13. A Review of High Voltage Drive Amplifiers for Capacitive Actuators

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.


    This paper gives an overview of the high voltage amplifiers, which are used to drive capacitive actuators. The amplifiers for both piezoelectric and DEAP (dielectric electroactive polymer) actuator are discussed. The suitable topologies for driving capacitive actuators are illustrated in detail, ......, including linear as well as switched mode amplifiers. In the past much attention has been paid on the driver for piezoelectric actuator. As DEAP is a type of new material, there is not much literature reference for it.......This paper gives an overview of the high voltage amplifiers, which are used to drive capacitive actuators. The amplifiers for both piezoelectric and DEAP (dielectric electroactive polymer) actuator are discussed. The suitable topologies for driving capacitive actuators are illustrated in detail...

  14. Low-κ' dielectric properties of UV-treated bi-axially oriented polypropylene films (United States)

    Dervos, C. T.; Tarantili, P. A.; Athanassopoulou, M. D.


    A 40 µm multilayer bi-axially oriented polypropylene (BOPP) film, was fabricated by the tenter process and its dielectric response was investigated after applying combined action of UV, humidity and heat. Dissipation factor (tan δ) and relative dielectric constant measurements were performed via the capacitance method for frequencies 20Hz-1 GHz. These results show that the relative dielectric constant (κ') reduces towards ultra low values (1.8) with an increasing number of applied UV-condensation cycles without any subsequent increase in the dielectric loss. Having no added physical porosity and absence of fluorine atoms, the irradiated BOPP structures offer significant advantages over poly(tetrafluoroethylene) PTFE due to reduced polarization effects, lower dielectric constant values and chemical stability to the adjacent copper or aluminium conductors. Possible application fields are dry type high-voltage capacitors and insulation within electronic components.

  15. Localised strain sensing of dielectric elastomers in a stretchable soft-touch musical keyboard (United States)

    Xu, Daniel; Tairych, Andreas; Anderson, Iain A.


    We present a new sensing method that can measure the strain at different locations in a dielectric elastomer. The method uses multiple sensing frequencies to target different regions of the same dielectric elastomer to simultaneously detect position and pressure using only a single pair of connections. The dielectric elastomer is modelled as an RC transmission line and its internal voltage and current distribution used to determine localised capacitance changes resulting from contact and pressure. This sensing method greatly simplifies high degree of freedom systems and does not require any modifications to the dielectric elastomer or sensing hardware. It is demonstrated on a multi-touch musical keyboard made from a single low cost carbon-based dielectric elastomer with 4 distinct musical tones mapped along a length of 0.1m. Loudness was controlled by the amount of pressure applied to each of these 4 positions.

  16. Attosecond clocking of scattering dynamics in dielectrics (United States)

    Kling, Matthias


    In the past few years electronic-device scaling has progressed rapidly and miniaturization has reached physical gate lengths below 100 nm, heralding the age of nanoelectronics. Besides the effort in size scaling of integrated circuits, tremendous progress has recently been made in increasing the switching speed where strong-field-based ``dielectric-electronics'' may push it towards the petahertz frontier. In this contest, the investigation of the electronic collisional dynamics occurring in a dielectric material is of primary importance to fully understand the transport properties of such future devices. Here, we demonstrate attosecond chronoscopy of electron collisions in SiO2. In our experiment, a stream of isolated aerodynamically focused SiO2 nanoparticles of 50 nm diameter was delivered into the laser interaction region. Photoemission is initiated by an isolated 250 as pulse at 35 eV and the electron dynamics is traced by attosecond streaking using a delayed few-cycle laser pulse at 700 nm. Electrons were detected by a kilohertz, single-shot velocity-map imaging spectrometer, permitting to separate frames containing nanoparticle signals from frames containing the response of the reference gas only. We find that the nanoparticle photoemission exhibits a positive temporal shift with respect to the reference. In order to understand the physical origin of the shift we performed semi-classical Monte-Carlo trajectory simulations taking into account the near-field distributions in- and outside the nanoparticles as obtained from Mie theory. The simulations indicate a pronounced dependence of the streaking time shift near the highest measured electron energies on the inelastic scattering time, while elastic scattering only shows a small influence on the streaking time shift for typical dielectric materials. We envision our approach to provide direct time-domain access to inelastic scattering for a wide range of dielectrics.

  17. Wide Operating Voltage Range Fuel Cell Battery Charger

    DEFF Research Database (Denmark)

    Hernandez Botella, Juan Carlos; Mira Albert, Maria del Carmen; Sen, Gokhan;


    DC-DC converters for fuel cell applications require wide voltage range operation due to the unique fuel cell characteristic curve. Primary parallel isolated boost converter (PPIBC) is a boost derived topology for low voltage high current applications reaching an efficiency figure up to 98.2 %. Th...

  18. Wide Operating Voltage Range Fuel Cell Battery Charger

    DEFF Research Database (Denmark)

    Hernandez Botella, Juan Carlos; Mira Albert, Maria del Carmen; Sen, Gokhan


    DC-DC converters for fuel cell applications require wide voltage range operation due to the unique fuel cell characteristic curve. Primary parallel isolated boost converter (PPIBC) is a boost derived topology for low voltage high current applications reaching an efficiency figure up to 98.2 %. Th...

  19. Antenna with Dielectric Having Geometric Patterns (United States)

    Dudley, Kenneth L. (Inventor); Elliott, Holly A. (Inventor); Cravey, Robin L. (Inventor); Connell, John W. (Inventor); Ghose, Sayata (Inventor); Watson, Kent A. (Inventor); Smith, Jr., Joseph G. (Inventor)


    An antenna includes a ground plane, a dielectric disposed on the ground plane, and an electrically-conductive radiator disposed on the dielectric. The dielectric includes at least one layer of a first dielectric material and a second dielectric material that collectively define a dielectric geometric pattern, which may comprise a fractal geometry. The radiator defines a radiator geometric pattern, and the dielectric geometric pattern is geometrically identical, or substantially geometrically identical, to the radiator geometric pattern.

  20. Self-stabilizing dielectric elastomer generators (United States)

    Zanini, P.; Rossiter, J.; Homer, M.


    Dielectric elastomer generators (DEGs) are an emerging technology for the conversion of mechanical into electrical energy. Despite many advantageous characteristics, there are still issues to overcome, including the need for charging at every cycle to produce an electrical output. Self-priming circuits (SPCs) are one possible solution, storing part of the electric energy output of one cycle to supply as input for the next, producing a voltage boost effect. Until now, studies regarding SPCs neglect to consider how the increasing voltage will create an electromechanical response and affect the DEG when driven by an oscillatory mechanical load. In the present work we model this force-based actuation, including coupling between the DEG and SPC, in order to predict the dynamics of the system. In such cases, the DEG has a mechanical response when charged (actuator behaviour), and as the voltage increases, this actuation-like effect increases the capacitance values that bound the cycle. We show how this inherent nonlinearity yields a reduction in the DEG’s capacitance swing and reduces the performance of the SPC, but also self-stabilizes the system. This stability is useful in the design of robust DEG energy harvesters that can operate near to, but not enter, failure mode.

  1. Organic nanodielectrics for low voltage carbon nanotube thin film transistors and complementary logic gates. (United States)

    Hur, Seung-Hyun; Yoon, Myung-Han; Gaur, Anshu; Shim, Moonsub; Facchetti, Antonio; Marks, Tobin J; Rogers, John A


    We report the implementation of three dimensionally cross-linked, organic nanodielectric multilayers as ultrathin gate dielectrics for a type of thin film transistor device that uses networks of single-walled carbon nanotubes as effective semiconductor thin films. Unipolar n- and p-channel devices are demonstrated by use of polymer coatings to control the behavior of the networks. Monolithically integrating these devices yields complementary logic gates. The organic multilayers provide exceptionally good gate dielectrics for these systems and allow for low voltage, low hysteresis operation. The excellent performance characteristics suggest that organic dielectrics of this general type could provide a promising path to SWNT-based thin film electronics.

  2. The Dynamic Fracture Process in Rocks Under High-Voltage Pulse Fragmentation (United States)

    Cho, Sang Ho; Cheong, Sang Sun; Yokota, Mitsuhiro; Kaneko, Katsuhiko


    High-voltage pulse technology has been applied to rock excavation, liberation of microfossils, drilling of rocks, oil and water stimulation, cleaning castings, and recycling products like concrete and electrical appliances. In the field of rock mechanics, research interest has focused on the use of high-voltage pulse technology for drilling and cutting rocks over the past several decades. In the use of high-voltage pulse technology for drilling and cutting rocks, it is important to understand the fragmentation mechanism in rocks subjected to high-voltage discharge pulses to improve the effectiveness of drilling and cutting technologies. The process of drilling rocks using high-voltage discharge is employed because it generates electrical breakdown inside the rocks between the anode and cathode. In this study, seven rock types and a cement paste were electrically fractured using high-voltage pulse discharge to investigate their dielectric breakdown properties. The dielectric breakdown strengths of the samples were compared with their physical and mechanical properties. The samples with dielectric fractured were scanned using a high-resolution X-ray computed tomography system to observe the fracture formation associated with mineral constituents. The fracture patterns of the rock samples were analyzed using numerical simulation for high-voltage pulse-induced fragmentation that adopts the surface traction and internal body force conditions.

  3. PD-Detection vs. Loss Measurements at High Voltages with variable frequencies

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Edin, Hans


    Partial discharge-activity (PD) in internal voids in epoxy plastic was measured at AC voltages from below inception to 3 times inception with variable frequencies in the range 0.1 to 100Hz.The results from phase/height analyses were compared to dielec-tric loss measurements and related to the app......Partial discharge-activity (PD) in internal voids in epoxy plastic was measured at AC voltages from below inception to 3 times inception with variable frequencies in the range 0.1 to 100Hz.The results from phase/height analyses were compared to dielec-tric loss measurements and related...

  4. Dielectric Barrier Discharge Plasma Actuator for Flow Control (United States)

    Opaits, Dmitry, F.


    This report is Part II of the final report of NASA Cooperative Agreement contract no. NNX07AC02A. It includes a Ph.D. dissertation. The period of performance was January 1, 2007 to December 31, 2010. Part I of the final report is the overview published as NASA/CR-2012- 217654. Asymmetric dielectric barrier discharge (DBD) plasma actuators driven by nanosecond pulses superimposed on dc bias voltage are studied experimentally. This produces non-self-sustained discharge: the plasma is generated by repetitive short pulses, and the pushing of the gas occurs primarily due to the bias voltage. The parameters of ionizing pulses and the driving bias voltage can be varied independently, which adds flexibility to control and optimization of the actuators performance. The approach consisted of three elements coupled together: the Schlieren technique, burst mode of plasma actuator operation, and 2-D numerical fluid modeling. During the experiments, it was found that DBD performance is severely limited by surface charge accumulation on the dielectric. Several ways to mitigate the surface charge were found: using a reversing DC bias potential, three-electrode configuration, slightly conductive dielectrics, and semi conductive coatings. Force balance measurements proved the effectiveness of the suggested configurations and advantages of the new voltage profile (pulses+bias) over the traditional sinusoidal one at relatively low voltages. In view of practical applications certain questions have been also addressed, such as electrodynamic effects which accompany scaling of the actuators to real size models, and environmental effects of ozone production by the plasma actuators.

  5. Electrical properties and dielectric spectroscopy of Ar+ implanted polycarbonate (United States)

    Chawla, Mahak; Shekhawat, Nidhi; Aggarwal, Sanjeev; Sharma, Annu; Nair, K. G. M.


    The aim of the present paper is to study the effect of argon ion implantation on electrical and dielectric properties of polycarbonate. Specimens were implanted with 130 keV Ar+ ions in the fluence ranging from 1×1014 to 1×1016 ions cm-2. The beam current used was ˜0.40 µA cm-2. The electrical conduction behaviour of virgin and Ar+ implanted polycarbonate specimens have been studied through current-voltage (I-V characteristic) measurements. It has been observed that after implantation conductivity increases with increasing ion fluence. The dielectric spectroscopy of these specimens has been done in the frequency range of 100 kHz-100 MHz. Relaxation processes were studied by Cole-Cole plot of complex permittivity (real part of complex permittivity, ɛ' vs. imaginary part of complex permittivity, ɛ″). The Cole-Cole plots have also been used to determine static dielectric constant (ɛs), optical dielectric constant (ɛ∞), spreading factor (α), average relaxation time (τ0) and molecular relaxation time (τ). The dielectric behaviour has been found to be significantly affected due to Ar+ implantation. The possible correlation between this behaviour and the changes induced by the implantation has been discussed.

  6. SEMICONDUCTOR DEVICES Low voltage copper phthalocyanine organic thin film transistors with a polymer layer as the gate insulator (United States)

    Xueqiang, Liu; Weihong, Bi; Tong, Zhang


    Low voltage organic thin film transistors (OTFTs) were created using polymethyl-methacrylate-co g-lyciclyl-methacrylate (PMMA-GMA) as the gate dielectric. The OTFTs performed acceptably at supply voltages of about 10 V. From a densely packed copolymer brush, a leakage current as low as 2 × 10-8 A/cm2 was obtained. From the measured capacitance—insulator frequency characteristics, a dielectric constant in the range 3.9-5.0 was obtained. By controlling the thickness of the gate dielectric, the threshold voltage was reduced from -3.5 to -2.0 V. The copper phthalocyanine (CuPc) based organic thin film transistor could be operated at low voltage and 1.2 × 10-3 cm2/(V·s) mobility.

  7. Broadband local dielectric spectroscopy (United States)

    Labardi, M.; Lucchesi, M.; Prevosto, D.; Capaccioli, S.


    A route to extend the measurement bandwidth of local dielectric spectroscopy up to the MHz range has been devised. The method is based on a slow amplitude modulation at a frequency Ω of the excitation field oscillating at a frequency ω and the coherent detection of the modulated average electric force or force gradient at Ω. The cantilever mechanical response does not affect the measurement if Ω is well below its resonant frequency; therefore, limitations on the excitation field frequency are strongly reduced. Demonstration on a thin poly(vinyl acetate) film is provided, showing its structural relaxation spectrum on the local scale up to 45 °C higher than glass temperature, and nanoscale resolution dielectric relaxation imaging near conductive nanowires embedded in the polymer matrix was obtained up to 5 MHz frequency, with no physical reason to hinder further bandwidth extension.

  8. Effect of voltage shape of electrical power supply on radiation and density of a cold atmospheric argon plasma jet


    F. Sohbatzadeh; Bagheri, M; S. Motallebi


    In this work, we investigated generating argon cold plasma jet at atmospheric pressure based on dielectric barrier discharge configuration using three electrical power supplies of sinusoidal, pulsed and saw tooth high voltage shapes at 8 KHZ. At first; we describe the electronic circuit features for generating high voltage (HV) wave forms including saw tooth, sinusoidal and pulsed forms. Then, we consider the effect of voltage shape on the electrical breakdown. Relative concentrations of chem...

  9. All-dielectric metamaterials. (United States)

    Jahani, Saman; Jacob, Zubin


    The ideal material for nanophotonic applications will have a large refractive index at optical frequencies, respond to both the electric and magnetic fields of light, support large optical chirality and anisotropy, confine and guide light at the nanoscale, and be able to modify the phase and amplitude of incoming radiation in a fraction of a wavelength. Artificial electromagnetic media, or metamaterials, based on metallic or polar dielectric nanostructures can provide many of these properties by coupling light to free electrons (plasmons) or phonons (phonon polaritons), respectively, but at the inevitable cost of significant energy dissipation and reduced device efficiency. Recently, however, there has been a shift in the approach to nanophotonics. Low-loss electromagnetic responses covering all four quadrants of possible permittivities and permeabilities have been achieved using completely transparent and high-refractive-index dielectric building blocks. Moreover, an emerging class of all-dielectric metamaterials consisting of anisotropic crystals has been shown to support large refractive index contrast between orthogonal polarizations of light. These advances have revived the exciting prospect of integrating exotic electromagnetic effects in practical photonic devices, to achieve, for example, ultrathin and efficient optical elements, and realize the long-standing goal of subdiffraction confinement and guiding of light without metals. In this Review, we present a broad outline of the whole range of electromagnetic effects observed using all-dielectric metamaterials: high-refractive-index nanoresonators, metasurfaces, zero-index metamaterials and anisotropic metamaterials. Finally, we discuss current challenges and future goals for the field at the intersection with quantum, thermal and silicon photonics, as well as biomimetic metasurfaces.

  10. Dielectric Metamaterial Reflector (United States)


    induced plasma coupled to a fluidized bed reactor have been utilized at SRI for 20+ years. As such, it would seem that Si particles may be easier to... etching process limits this process to cm2 areas. There have been several studies and demonstrations of the optical properties of dilute as well...magnetic optical response in a dielectric nanoparticle by ultrafast photoexcitation of dense electron–hole plasma . Nano letters, 15(9), pp.6187-6192. 34

  11. All-dielectric metamaterials (United States)

    Jahani, Saman; Jacob, Zubin


    The ideal material for nanophotonic applications will have a large refractive index at optical frequencies, respond to both the electric and magnetic fields of light, support large optical chirality and anisotropy, confine and guide light at the nanoscale, and be able to modify the phase and amplitude of incoming radiation in a fraction of a wavelength. Artificial electromagnetic media, or metamaterials, based on metallic or polar dielectric nanostructures can provide many of these properties by coupling light to free electrons (plasmons) or phonons (phonon polaritons), respectively, but at the inevitable cost of significant energy dissipation and reduced device efficiency. Recently, however, there has been a shift in the approach to nanophotonics. Low-loss electromagnetic responses covering all four quadrants of possible permittivities and permeabilities have been achieved using completely transparent and high-refractive-index dielectric building blocks. Moreover, an emerging class of all-dielectric metamaterials consisting of anisotropic crystals has been shown to support large refractive index contrast between orthogonal polarizations of light. These advances have revived the exciting prospect of integrating exotic electromagnetic effects in practical photonic devices, to achieve, for example, ultrathin and efficient optical elements, and realize the long-standing goal of subdiffraction confinement and guiding of light without metals. In this Review, we present a broad outline of the whole range of electromagnetic effects observed using all-dielectric metamaterials: high-refractive-index nanoresonators, metasurfaces, zero-index metamaterials and anisotropic metamaterials. Finally, we discuss current challenges and future goals for the field at the intersection with quantum, thermal and silicon photonics, as well as biomimetic metasurfaces.

  12. Dielectric spectroscopy of polyaniline

    Energy Technology Data Exchange (ETDEWEB)

    Calleja, R.D.; Matveeva, E.M. [Polytechnical Univ. of Valencia, (Spain)


    Polyaniline films (PANI) are being considered as attractive new galvanic sources, electrochromic displays, chemical sensors, etc. So far much work has been done to study their optical, electrochemical and electrical properties. However, there are still doubts about the basic electric conductivity mechanisms of PANI. The aim of this paper is to study the influence of water molecules and acid anions on the properties of PANI films by dielectric spectroscopy.

  13. High Voltage Distribution (United States)

    Norbeck, Edwin; Miller, Michael; Onel, Yasar


    For detector arrays that require 5 to 10 kV at a few microamps each for hundreds of detectors, using hundreds of HV power supplies is unreasonable. Bundles of hundreds of HV cables take up space that should be filled with detectors. A typical HV module can supply 1 ma, enough current for hundreds of detectors. It is better to use a single HV module and distribute the current as needed. We show a circuit that, for each detector, measures the current, cuts off the voltage if the current exceeds a set maximum, and allows the HV to be turned on or off from a control computer. The entire array requires a single HV cable and 2 or 3 control lines. This design provides the same voltage to all of the detectors, the voltage set by the single HV module. Some additional circuitry would allow a computer controlled voltage drop between the HV and each individual detector.

  14. Experimental validation of prototype high voltage bushing (United States)

    Shah, Sejal; Tyagi, H.; Sharma, D.; Parmar, D.; M. N., Vishnudev; Joshi, K.; Patel, K.; Yadav, A.; Patel, R.; Bandyopadhyay, M.; Rotti, C.; Chakraborty, A.


    Prototype High voltage bushing (PHVB) is a scaled down configuration of DNB High Voltage Bushing (HVB) of ITER. It is designed for operation at 50 kV DC to ensure operational performance and thereby confirming the design configuration of DNB HVB. Two concentric insulators viz. Ceramic and Fiber reinforced polymer (FRP) rings are used as double layered vacuum boundary for 50 kV isolation between grounded and high voltage flanges. Stress shields are designed for smooth electric field distribution. During ceramic to Kovar brazing, spilling cannot be controlled which may lead to high localized electrostatic stress. To understand spilling phenomenon and precise stress calculation, quantitative analysis was performed using Scanning Electron Microscopy (SEM) of brazed sample and similar configuration modeled while performing the Finite Element (FE) analysis. FE analysis of PHVB is performed to find out electrical stresses on different areas of PHVB and are maintained similar to DNB HV Bushing. With this configuration, the experiment is performed considering ITER like vacuum and electrical parameters. Initial HV test is performed by temporary vacuum sealing arrangements using gaskets/O-rings at both ends in order to achieve desired vacuum and keep the system maintainable. During validation test, 50 kV voltage withstand is performed for one hour. Voltage withstand test for 60 kV DC (20% higher rated voltage) have also been performed without any breakdown. Successful operation of PHVB confirms the design of DNB HV Bushing. In this paper, configuration of PHVB with experimental validation data is presented.

  15. Study of HV Dielectrics for High Frequency Operation in Linear & Nonlinear Transmission Lines & Simulation & Development of Hybrid Nonlinear Lines for RF Generation (United States)


    The high voltage diodes D5 to D10 are used to protect the HV switch against negative back swing voltage, while D4 diode for reverse current ...AFRL-AFOSR-CL-TR-2015-0001 STUDY OF HV DIELECTRICS FOR HIGH FREQUENCY OPERATION IN LINEAR & NONLINEAR TRANSMISSION LINES & SIMULATION & DEVELOPMENT...AFOSR Final Performance Report Study of HV Dielectrics for High Frequency Operation in Linear and Nonlinear Transmission Lines and Simulation

  16. Study of HV Dielectrics for High Frequency Operation in Linear and Nonlinear Transmission Lines (NLTLs) and Simulation and Development of Hybrid Nonlinear Lines for RF Generation (United States)


    have better performance than BT-based dielectrics in this frequency range because of the PZT lower loss tangent. The reason is that PZT dielectric...during pulse formation the top of the reflected voltage pulse travels faster along the line than its bottom distorting the voltage step into a ramp... inductances due to component geometry or terminals limits the output frequency in NLTLs. As shown in Fig. 6, as expected the permittivity for all

  17. SU-8 as Hydrophobic and Dielectric Thin Film in Electrowetting-on-Dielectric Based Microfluidics Device

    Directory of Open Access Journals (Sweden)

    Vijay Kumar


    Full Text Available Electrowetting-on-dielectric (EWOD based droplet actuation in microfluidic chip is designed and fabricated. EWOD is used as on-chip micro-pumping scheme for moving fluid digitally in Lab-on-a-chip devices. For enabling this scheme, stacked deposition of thin dielectric and hydrophobic layer in that order between microchannel and electrodes is done. The present paper investigates the potential use of SU-8 as hydrophobic layer in conjunction of acting as dielectric in the device. The objective for the investigation is to lower the cost and a thin simplification in fabrication process of EWOD-based devices. We have done design and optimization of dimensions of electrode array including gap between arrays for EWOD micropump. Design and optimization are carried out in CoventorWare. The designing is followed by fabrication of device and analysis for droplet motion. The fabrication of the device includes array of electrodes over the silicon surface and embedding them in hydrophobic SU-8 layer. Water droplet movement in the order of microliter of spherical shape is demonstrated. It has been shown that an SU-8 microchannel in the current design allows microfluidic flow at tens of voltages comparable with costlier and more complicated to fabricate designs reported in the literature.

  18. Tunable dielectric properties of ferrite-dielectric based metamaterial. (United States)

    Bi, K; Huang, K; Zeng, L Y; Zhou, M H; Wang, Q M; Wang, Y G; Lei, M


    A ferrite-dielectric metamaterial composed of dielectric and ferrite cuboids has been investigated by experiments and simulations. By interacting with the electromagnetic wave, the Mie resonance can take place in the dielectric cuboids and the ferromagnetic precession will appear in the ferrite cuboids. The magnetic field distributions show the electric Mie resonance of the dielectric cuboids can be influenced by the ferromagnetic precession of ferrite cuboids when a certain magnetic field is applied. The effective permittivity of the metamaterial can be tuned by modifying the applied magnetic field. A good agreement between experimental and simulated results is demonstrated, which confirms that these metamaterials can be used for tunable microwave devices.

  19. Low-voltage gyrotrons (United States)

    Glyavin, M. Yu.; Zavolskiy, N. A.; Sedov, A. S.; Nusinovich, G. S.


    For a long time, the gyrotrons were primarily developed for electron cyclotron heating and current drive of plasmas in controlled fusion reactors where a multi-megawatt, quasi-continuous millimeter-wave power is required. In addition to this important application, there are other applications (and their number increases with time) which do not require a very high power level, but such issues as the ability to operate at low voltages and have compact devices are very important. For example, gyrotrons are of interest for a dynamic nuclear polarization, which improves the sensitivity of the nuclear magnetic resonance spectroscopy. In this paper, some issues important for operation of gyrotrons driven by low-voltage electron beams are analyzed. An emphasis is made on the efficiency of low-voltage gyrotron operation at the fundamental and higher cyclotron harmonics. These efficiencies calculated with the account for ohmic losses were, first, determined in the framework of the generalized gyrotron theory based on the cold-cavity approximation. Then, more accurate, self-consistent calculations for the fundamental and second harmonic low-voltage sub-THz gyrotron designs were carried out. Results of these calculations are presented and discussed. It is shown that operation of the fundamental and second harmonic gyrotrons with noticeable efficiencies is possible even at voltages as low as 5-10 kV. Even the third harmonic gyrotrons can operate at voltages about 15 kV, albeit with rather low efficiency (1%-2% in the submillimeter wavelength region).

  20. Resonances and dipole moments in dielectric, magnetic, and magnetodielectric cylinders

    DEFF Research Database (Denmark)

    Dirksen, A.; Arslanagic, Samel; Breinbjerg, Olav


    An eigenfunction solution to the problem of plane wave scattering by dielectric, magnetic, and magnetodielectric cylinders is used for a systematic investigation of their resonances. An overview of the resonances with electric and magnetic dipole moments, needed in, e.g., the synthesis...... of metamaterials, is given with an emphasis on their strength, bandwidth, and isolation....

  1. Characterization, Microstructure, and Dielectric properties of cubic pyrochlore structural ceramics

    KAUST Repository

    Li, Yangyang


    The (BMN) bulk materials were sintered at 1050°C, 1100°C, 1150°C, 1200°C by the conventional ceramic process, and their microstructure and dielectric properties were investigated by Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, Transmission electron microscopy (TEM) (including the X-ray energy dispersive spectrometry EDS and high resolution transmission electron microscopy HRTEM) and dielectric impedance analyzer. We systematically investigated the structure, dielectric properties and voltage tunable property of the ceramics prepared at different sintering temperatures. The XRD patterns demonstrated that the synthesized BMN solid solutions had cubic phase pyrochlore-type structure when sintered at 1050°C or higher, and the lattice parameter (a) of the unit cell in BMN solid solution was calculated to be about 10.56Å. The vibrational peaks observed in the Raman spectra of BMN solid solutions also confirmed the cubic phase pyrochlore-type structure of the synthesized BMN. According to the Scanning Electron Microscope (SEM) images, the grain size increased with increasing sintering temperature. Additionally, it was shown that the densities of the BMN ceramic tablets vary with sintering temperature. The calculated theoretical density for the BMN ceramic tablets sintered at different temperatures is about 6.7521 . The density of the respective measured tablets is usually amounting more than 91% and 5 approaching a maximum value of 96.5% for sintering temperature of 1150°C. The microstructure was investigated by using Scanning Transmission Electron Microscope (STEM), X-ray diffraction (XRD). Combined with the results obtained from the STEM and XRD, the impact of sintering temperature on the macroscopic and microscopic structure was discussed. The relative dielectric constant ( ) and dielectric loss ( ) of the BMN solid solutions were measured to be 161-200 and (at room temperature and 100Hz-1MHz), respectively. The BMN solid

  2. Electrowetting on dielectrics on lubricating fluid based slippery surfaces with negligible hysteresis


    Barman, Jitesh; Nagarajan, Arun Kumar; Khare, Krishnacharya


    Low voltage electrowetting on dielectrics on substrates with thin layer of lubricating fluid to reduce contact angle hysteresis is reported here. On smooth and homogeneous solid surfaces, it is extremely difficult to reduce contact angle hysteresis (contact angle difference between advancing and receding drop volume cycle) and the electrowetting hysteresis (contact angle difference between advancing and receding voltage cycle) below 10{\\deg}. On the other hand, electrowetting hysteresis on ro...

  3. Self-Organized Filaments in Dielectric Barrier Discharge in Air at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    DONG Li-Fang; LI Xue-Chen; YINZeng-Qian; QIAN Sheng-Fa; OUYANG Ji-Ting; WANG Long


    The self-organized filament pattern created by dielectric barrier discharges in air at atmospheric pressure is investigated experimentally. The density and dimension of filament are analysed quantitatively. The experimental results show that the distance between neighbouring filaments decreases with the increased applied voltage or with the decreased width of the gas gap. Also, the diameter of the filament decreases with the increased applied voltages or with the decreased width of the gas gap.

  4. The Control Unit of a Single Phase Voltage Regulator

    CERN Document Server

    Colak, Ilknur


    Supplying regulated voltage to critical loads is an important topic for several years. This paper presents a single-phase electronic voltage regulator based on high frequency switching of an isolated transformer where primary side voltage is controlled by two full-bridge converters sharing a common DC bus and operating at 50Hz and 20kHz switching frequencies. This allows 50Hz induced voltage on the primary side of the transformer, regulated by high frequency switching. Depending on the input voltage, voltage at the secondary side of the transformer add to (boost mode) or subtract (buck mode) from the supply voltage, therefore, maintaining a regulated voltage value across the load. The regulator is controlled by a digital controller allowing fast dynamic response. A 5kVA single-phase voltage regulator is realized to verify the operation of the proposed algorithm. The experimental results show that regulator maintains constant voltage across the load both in step-up (low supply voltage) and step-down (high supp...

  5. Dielectric loss determination using perturbation


    Andrawis, Madeleine Y.


    A dielectric filled cavity structure is currently being used to estimate the dielectric constant and loss factor over a wide range of frequencies of a dielectric material which fills the cavity structure [Saed, 1987]. A full field analysis is used to compute the effective complex permittivity of the sample material based on reflection coefficient measurements of the cavity structure and associated geometrical dimensions. The method has previously been used successfully to de...

  6. Device for monitoring cell voltage (United States)

    Doepke, Matthias [Garbsen, DE; Eisermann, Henning [Edermissen, DE


    A device for monitoring a rechargeable battery having a number of electrically connected cells includes at least one current interruption switch for interrupting current flowing through at least one associated cell and a plurality of monitoring units for detecting cell voltage. Each monitoring unit is associated with a single cell and includes a reference voltage unit for producing a defined reference threshold voltage and a voltage comparison unit for comparing the reference threshold voltage with a partial cell voltage of the associated cell. The reference voltage unit is electrically supplied from the cell voltage of the associated cell. The voltage comparison unit is coupled to the at least one current interruption switch for interrupting the current of at least the current flowing through the associated cell, with a defined minimum difference between the reference threshold voltage and the partial cell voltage.

  7. Dielectric properties of fly ash

    Indian Academy of Sciences (India)

    S C Raghavendra; R L Raibagkar; A B Kulkarni


    This paper reports the dielectric properties of fly ash. The dielectric measurements were performed as a function of frequency and temperature. The sample of fly ash shows almost similar behaviour in the frequency and temperature range studied. The large value of dielectric constant in the typical frequency range is because of orientation polarization and tight binding force between the ions or atoms in the fly ash. The sample of fly ash is of great scientific and technological interest because of its high value of dielectric constant (104).

  8. High voltage pulse generator (United States)

    Fasching, George E.


    An improved high-voltage pulse generator has been provided which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of a first one of the rectifiers connected between the first and second of the plurality of charging capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. Alternate circuits are provided for controlling the application of the charging voltage from a charging circuit to be applied to the parallel capacitors which provides a selection of at least two different intervals in which the charging voltage is turned "off" to allow the SCR's connecting the capacitors in series to turn "off" before recharging begins. The high-voltage pulse-generating circuit including the N capacitors and corresponding SCR's which connect the capacitors in series when triggered "on" further includes diodes and series-connected inductors between the parallel-connected charging capacitors which allow sufficiently fast charging of the capacitors for a high pulse repetition rate and yet allow considerable control of the decay time of the high-voltage pulses from the pulse-generating circuit.

  9. Cobalt iron-oxide nanoparticle modified poly(methyl methacrylate) nanodielectrics. Dielectric and electrical insulation properties (United States)

    Tuncer, Enis; Rondinone, Adam J.; Woodward, Jonathan; Sauers, Isidor; James, D. Randy; Ellis, Alvin R.


    In this paper, we report the dielectric properties of composite systems (nanodielectrics) made of small amounts of mono dispersed magnetic nanoparticles embedded in a polymer matrix. It is observed from the transmission electron microscope images that the matrix polymeric material is confined in approximately 100 nm size cages between particle clusters. The particle clusters are composed of separated spherical particles which comprise unconnected networks in the matrix. The dielectric relaxation and breakdown characteristics of the matrix polymeric material are altered with the addition of nanometer size cobalt iron-oxide particles. The dielectric breakdown measurements performed at 77 K showed that these nanodielectrics are potentially useful as an electrical insulation material for cryogenic high voltage applications. Finally, structural and dielectric properties of nanocomposite dielectrics are discussed to present plausible reasons for the observed low effective dielectric permittivity values in the present and similar nanodielectric systems. It is concluded that polymeric nanoparticle composites would have low dielectric permittivity regardless of the permittivity of nanoparticles are when the particles are coordinated with a low dielectric permittivity surfactant.

  10. Study of the interaction between space plasma and high voltage solar array


    Iwasa, Minoru; TANAKA, KOJI; Sasaki, Susumu; ODAWARA, OSAMU; 岩佐 稔; 田中 孝治; 佐々木 進; 小田原 修


    We are studying the problems associated with high voltage power systems in space. Especially we are interested in the potential distribution of the solar array that is resistant to the electrical discharge. We have carried out experiment on the interaction between the space plasma and the high voltage solar array. An array of electrodes distributed on a dielectric material was used to simulate the inter-connectors of the solar array panel in space environment. One of major concerns in the usa...

  11. Electrical modeling of dielectric elastomer stack transducers (United States)

    Haus, Henry; Matysek, Marc; Moessinger, Holger; Flittner, Klaus; Schlaak, Helmut F.


    Performance of dielectric elastomer transducers (DEST) depends on mechanical and electrical parameters. For designing DEST it is therefore necessary to know the influences of these parameters on the overall performance. We show an electrical equivalent circuit valid for a transducer consisting of multiple layers and derive the electrical parameters of the circuit depending on transducers geometry and surface resistivity of the electrodes. This allows describing the DESTs dynamic behavior as a function of fabrication (layout, sheet and interconnection resistance), material (breakdown strength, permittivity) and driving (voltage) parameters. Using this electrical model transfer function and cut-off frequency are calculated, describing the influence of transducer capacitance, resistance and driving frequency on the achievable actuation deflection. Furthermore non ideal boundary effects influencing the capacitance value of the transducer are investigated by an electrostatic simulation and limits for presuming a simple plate capacitor model for calculating the transducer capacitance are derived. Results provide the plate capacitor model is a valid assumption for typical transducer configurations but for certain aspect ratios of electrode dimensions to dielectric thickness -- arising e.g. in the application of tactile interfaces -- the influence of boundary effects is to be considered.

  12. Polyamide 66 as a cryogenic dielectric (United States)

    Tuncer, Enis; Polizos, Georgios; Sauers, Isidor; Randy James, D.; Ellis, Alvin R.; Messman, Jamie M.; Aytuğ, Tolga


    Improvements in superconductor and cryogenic technologies enable novel power apparatus, e.g., cables, transformers, fault current limiters, generators, it etc., with better device characteristics than their conventional counterparts. In these applications electrical insulation materials play an important role in system weight, footprint (size), and voltage level. The trend in the electrical insulation material selection has been to adapt or to employ conventional insulation materials to these new systems. However, at low temperatures, thermal contraction and loss of mechanical strength in many materials make them unsuitable for superconducting power applications. In this paper, a widely used commercial material was characterized as a potential cryogenic dielectric. The material is used in "oven bags" which is a heat-resistant polyamide (nylon) used in cooking (produced by ; this value is approximately 46kVmm higher than PPLP™. Comparison of the mechanical properties of PA and PPLP™ indicates that PA66 has low storage and loss moduli than PPLP™. It is concluded that PA66 may be a good candidate for cryogenic applications. Finally, a summary of dielectric properties of some of the commercial tape insulation materials and various polymers is also provided.

  13. Insulated DC-to-DC converter with wide input voltage range; Convertisseur continu-continu isole a large plage de tension d'entree: conception d'une alimentation 36 kW pour auxiliaire ferroviaire

    Energy Technology Data Exchange (ETDEWEB)

    Rieux, O.


    This thesis presents the research that has been carried out in the context of a collaboration contract between the FAIVELEY Transport company and the laboratoire d'Electrotechnique et d'Electronique Industrielle Laboratory. The goal of this research is the study of a converter that feeds a railway air conditioning unit, and that is fed by the overhead line voltage. It is an insulated DC-to-DC converter, of which input voltage varies from 2 to 5 kV, and output voltage is 600 V. This document introduces and justifies an original energy conversion principle. This principle is based on a series association of ZVS inverters, and a co-ordinated control that takes up the input voltage variations. This document also exposes detailed operation, and design rules applicable to converters based on this principle. Related studies are presented too, on such subjects as in situ reconnection of inverters for adapting to other overhead line types, or fault tolerance. Operation of such a converter has been studied by simulation, thus validating both the topology and the control modes. Experiments have also been carried out to check feasibility of a critical component of the structure: the saturable inductor. (author)

  14. Biocompatible/Degradable Silk Fibroin:Poly(Vinyl Alcohol)-Blended Dielectric Layer Towards High-Performance Organic Field-Effect Transistor (United States)

    Zhuang, Xinming; Huang, Wei; Yang, Xin; Han, Shijiao; Li, Lu; Yu, Junsheng


    Biocompatible silk fibroin (SF):poly(vinyl alcohol) (PVA) blends were prepared as the dielectric layers of organic field-effect transistors (OFETs). Compared with those with pure SF dielectric layer, an optimal threshold voltage of ~0 V, high on/off ratio of ~104, and enhanced field-effect mobility of 0.22 cm2/Vs of OFETs were obtained by carefully controlling the weight ratio of SF:PVA blends to 7:5. Through the morphology characterization of dielectrics and organic semiconductors by utilizing atom force microscopy and electrical characterization of the devices, the performance improvement of OFETs with SF:PVA hybrid gate dielectric layers were attributed to the smooth and homogeneous morphology of blend dielectrics. Furthermore, due to lower charge carrier trap density, the OFETs based on SF:PVA-blended dielectric exhibited a higher bias stability than those based on pure SF dielectric.

  15. The Space Charge Effect on the Discharge Current in Cross-Linked Polyethylene under High AC Voltages (United States)

    Kwon, Yoon-Hyeok; Hwangbo, Seung; Lee, June-Ho; Yi, Dong-Young; Han, Min-Koo


    The space charge distributions in solid dielectrics have been usually investigated by means of the pulsed electroacoustic (PEA) method. However, most previous studies have been limited to the phenomenological analysis under DC voltages. In our study, the space charge distribution in cross-linked polyethylene (XLPE) has been measured using AC voltages by means of the modified PEA method. Simultaneously, the streamer discharges in an air gap have been measured in order to investigate the relationship between space charge and discharge current, and the relationship has been adapted to the case of dielectric barrier discharge. At high AC voltages, discharge current increases to the critical point, but no further increase is exhibited over the critical voltage and the discharge pattern is resolved by the space charge. This result indicates that the frequency effect and space charge characteristics of dielectric materials are preferred to the voltage effect in the adaptation to dielectric barrier discharge. The results well explain the space charge effect on partial discharge and the dielectric barrier discharge phenomenon.

  16. Dielectric breakdown strength of magnetic nanofluid based on insulation oil after impulse test (United States)

    Nazari, M.; Rasoulifard, M. H.; Hosseini, H.


    In this study, the dielectric breakdown strength of magnetic nanofluids based on transformer mineral oil for use in power systems is reviewed. Nano oil samples are obtained from dispersion of the magnetic nanofluid within uninhibited transformer mineral oil NYTRO LIBRA as the base fluid. AC dielectric breakdown voltage measurement was carried out according to IEC 60156 standard and the lightning impulse breakdown voltage was obtained by using the sphere-sphere electrodes in an experimental setup for nano oil in volume concentration of 0.1-0.6%. Results indicate improved AC and lightning impulse breakdown voltage of nano oil compared to the base oil. AC test was performed again after applying impulse current and result showed that nano oil unlike the base oil retains its dielectric properties. Increase the dielectric strength of the nano oil is mainly due to dielectric and magnetic properties of Fe3O4 nanoparticles that act as free electrons snapper, and reduce the rate of free electrons in the ionization process.

  17. Dielectric materials and electrostatics

    CERN Document Server

    Gallot-Lavalle, Olivier


    An introduction to the physics of electrical insulation, this book presents the physical foundations of this discipline and the resulting applications. It is structured in two parts. The first part presents a mathematical and intuitive approach to dielectrics; various concepts, including polarization, induction, forces and losses are discussed. The second part provides readers with the keys to understanding the physics of solid, liquid and gas insulation. It comprises a phenomenological description of discharges in gas and its resulting applications. Finally, the main electrical properties

  18. Inorganic optical dielectric films (United States)

    Woollam, John A.


    Dielectric coatings have been in use for a very long time, yet today they represent a steadily growing wold-wide industry. A wide range of materials, and applications from the near ultraviolet into the infrared are in use, or under development. This paper is a brief survey, including references to the literature, and a discussion of materials diagnostics. Discussed is the microstructure, optical constants and their relationship as determined especially by optical measurements. This paper emphasizes the materials science aspects rather than applications.

  19. Study of predicting breakdown voltage of stator insulation in generator based on BP neural network

    Institute of Scientific and Technical Information of China (English)

    Jiang Yuao; Zhang Aide; Liu Libing; Du Yu; Gao Naikui; Peng Zongren


    The breakdown voltage plays an important role in evaluating residual life of stator insulation in generator. In this paper, we discussed BP neural network that was used to predict the breakdown voltage of stator insulation in generator of 300 MW/18 kV. At first the neural network has been trained by the samples that include the varieties of dielectric loss factor tanδ, the partial discharge parameters and breakdown voltage. Then we tried to predict the breakdown voltage of samples and stator insulations subjected to multi-stress aging by the trained neural network. We found that it's feasible and accurate to predict the voltage. This method can be applied to predict breakdown voltage of other generators which have the same insulation structure and material.

  20. Voltage Regulators for Photovoltaic Systems (United States)

    Delombard, R.


    Two simple circuits developed to provide voltage regulation for highvoltage (i.e., is greater than 75 volts) and low-voltage (i.e., is less than 36 volts) photovoltaic/battery power systems. Use of these circuits results in voltage regulator small, low-cost, and reliable, with very low power dissipation. Simple oscillator circuit controls photovoltaic-array current to regulate system voltage and control battery charging. Circuit senses battery (and system) voltage and adjusts array current to keep battery voltage from exceeding maximum voltage.

  1. Studying Voltage Transformer Ferroresonance

    Directory of Open Access Journals (Sweden)

    Hamid Radmanesh


    Full Text Available This study studies the effect of Circuit Breaker Shunt Resistance (CBSR, Metal Oxide Vaistor (MOV and Neutral earth Resistance (NR on the control of ferroresonance in the voltage transformer. It is expected that NR can controlled ferroresonance better than MOV and CBSR. Study has been done on a one phase voltage transformer rated 100 VA, 275 kV. The simulation results reveal that considering the CBSR and MOV exhibits a great mitigating effect on ferroresonance overvoltages, but these resistances cannot control these phenomena for all range of parameters. By applying NR to the system structure, ferroresonance has been controlled and its amplitude has been damped for all parameters values.

  2. High Thermal and Electrical Tunability of Negative Dielectric Liquid Crystal Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Scolari, Lara; Weirich, Johannes;


    We infiltrate photonic crystal fibers with negative dielectric liquid crystals. 400nm bandgap shift is obtained in the range 22ºC-80ºC and 119nm shift of the long-wavelength bandgap edge is achieved by applying a voltage of 200V....

  3. Theoretical analysis of a biased photonic crystal fiber infiltrated with a negative dielectric anisotropy liquid crystal

    DEFF Research Database (Denmark)

    Weirich, Johannes; Wei, Lei; Lægsgaard, Jesper;


    We simulate the PBG mode of a biased Photonic Crystal Fiber (PCF) infiltrated with a Liquid Crystal (LC) with negative dielectric anisotropy. We analyse the voltage induced change of the transmission spectrum, dispersion and losses and compare them to the experimental values....

  4. Geometry optimization of tubular dielectric elastomer actuators with anisotropic metallic electrodes

    DEFF Research Database (Denmark)

    Rechenbach, Björn; Willatzen, Morten; Sarban, R.;


    This paper presents an experimentally verified static three-dimensional model for core free tubular dielectric elastomer actuators with anisotropic compliant metal electrodes. Due to the anisotropy of the electrodes, the performance (force versus voltage, force versus stroke, and stroke versus vo...

  5. Measurement of Plasma Density Produced in Dielectric Barrier Discharge for Active Aerodynamic Control with Interferometer

    Institute of Scientific and Technical Information of China (English)

    LI Gang; ZHANG Yi; XU Yan-Ji; LIN Bin; LI Yu-Tong; ZHU Jun-Qiang


    We utilize an interferometer to investigate the changes of the refractive index caused by dielectric barrier discharge plasma.The electronic density of the plasma produced is measured and analyzed tentatively.The results show that density of the plasma increases linearly with exciting voltages.

  6. Casimir Effect for Dielectric Plates

    Institute of Scientific and Technical Information of China (English)


    We generalize Kupisewska method to the three-dimensional system and another derivation of the Casimir effect between two dielectric plates is presented based on the explicit quantization of the electromagnetic field in the presence of dielectrics, where the physical meaning of "evanescent mode" is discussed. The Lifshitz's formula is rederived perfect metallic plates will the evanescent modes become unimportant.

  7. Droplet creator based on electrowetting-on-dielectric for lab on a chip

    Institute of Scientific and Technical Information of China (English)


    Electrowetting-on-dielectric (EWOD) is to directly control the wettability of liquids on the solid surface by applying the electric potential to the microelectrode array under the dielectric layer. The prototype of the EWOD droplet creator with the sandwiched structure is used: the droplet is sandwiched between the top and bottom plates; the bottom plate consists of silicon used as the substrate of the microelectrode array, nitride silicon film deposited by low pressure chemical vapor deposition as the dielectric layer and the fluorocarbon polymer film deposited by inductively coupled plasma chemical vapor deposition as the hydrophobic layer; and the top plate is the transparent electrode covered with the hydrophobic layer. To obtain the required minimum voltage, the process and the criterion of creating droplets are analyzed. At the voltage of 35 V the deionized water droplet surrounded in silicone oil is successfully created.

  8. Methane conversion using a dielectric barrier discharge reactor at atmospheric pressure for hydrogen production (United States)

    Khadir, N.; Khodja, K.; Belasri, A.


    In the present paper, we carried out a theoretical study of dielectric barrier discharge (DBD) filled with pure methane gas. The homogeneous discharge model used in this work includes a plasma chemistry unit, an electrical circuit, and the Boltzmann equation. The model was applied to the case of a sinusoidal voltage at a period frequency of 50 kHz and under a gas pressure of 600 Torr. We investigated the temporal variation of electrical and kinetic discharge parameters such as plasma and dielectric voltages, the discharge current density, electric field, deposited power density, and the species concentration. We also checked the physical model validity by comparing its results with experimental work. According to the results discussed herein, the dielectric capacitance is the parameter that has the greatest effect on the methane conversion and H2/CH4 ratio. This work enriches the knowledge for the improvement of DBD for CH4 conversion and hydrogen production.

  9. Real-time dielectric-film thickness measurement system for plasma processing chamber wall monitoring. (United States)

    Kim, Jin-Yong; Chung, Chin-Wook


    An in-situ real-time processing chamber wall monitoring system was developed. In order to measure the thickness of the dielectric film, two frequencies of small sinusoidal voltage (∼1 V) signals were applied to an electrically floated planar type probe, which is positioned at chamber wall surface, and the amplitudes of the currents and the phase differences between the voltage and current were measured. By using an equivalent sheath circuit model including a sheath capacitance, the dielectric thickness can be obtained. Experiments were performed in various plasma condition, and reliable dielectric film thickness was obtained regardless of the plasma properties. In addition, availability in commercial chamber for plasma enhanced chemical vapor deposition was verified. This study is expected to contribute to the control of etching and deposition processes and optimization of periodic maintenance in semiconductor manufacturing process.

  10. Interaction between a microplasma array and an adjacent dielectric surface (United States)

    Dzikowski, Sebastian; Schulz-von der Gathen, Volker


    Microplasma pixel devices are interesting for applications such as surface modification. A representative is the metal grid array, which is a stable alternative to silicon-based arrays and consists of a dielectric, a grounded electrode and a metal grid with symmetrically arranged cavities. Typically, microplasma arrays are operated close to atmospheric pressure with noble gases like argon and helium. By applying a bipolar triangular voltage waveform with an amplitude of 700 V peak-to-peak and a frequency of 10 kHz to the metal grid, the discharge is ignited in the cavities having a diameter of about 200 and depth of 50 µm. For future applications, such as coating and catalysis, the interaction between the array and a dielectric surface positioned at close distance (emission spectroscopy, the phase dependent expansion of the emission out of the cavities has been observed. Here, we present results of investigations on the dependence of emission structures of the cavities (individually or as group) on pressure, applied voltage and distance between grid and dielectric. Supported by the DFG in the Research Unit FOR1123.

  11. Dielectric laser accelerators (United States)

    England, R. Joel; Noble, Robert J.; Bane, Karl; Dowell, David H.; Ng, Cho-Kuen; Spencer, James E.; Tantawi, Sami; Wu, Ziran; Byer, Robert L.; Peralta, Edgar; Soong, Ken; Chang, Chia-Ming; Montazeri, Behnam; Wolf, Stephen J.; Cowan, Benjamin; Dawson, Jay; Gai, Wei; Hommelhoff, Peter; Huang, Yen-Chieh; Jing, Chunguang; McGuinness, Christopher; Palmer, Robert B.; Naranjo, Brian; Rosenzweig, James; Travish, Gil; Mizrahi, Amit; Schachter, Levi; Sears, Christopher; Werner, Gregory R.; Yoder, Rodney B.


    The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. The physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV /m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

  12. Influence of Gate Dielectric and Its Surface Treatment on Electrical Characteristics of Solution-Processed ZnO Transistors. (United States)

    Song, Dong-Seok; Kim, Jae-Hyun; Jung, Ji-Hoon; Bae, Jin-Hyuk; Zhang, Xue; Park, Ji-Ho; Park, Jaehoon


    We report how interface treatments affect electrical performance, including subthreshold characteristics, in solution-processed transparent metal oxide thin-film transistors (TFTs) with SiO2 and SiNx gate dielectrics. Ultra-violet (UV) ozone treatment and O2 plasma treatment are carried out as a surface treatment of the interface between a spin-coated zinc oxide (ZnO) layer and a gate dielectric. With the SiO2 dielectric, UV ozone treatment dominantly affects subthreshold characteristics, while O2 plasma treatment produces enhanced mobility and lower threshold voltage shift. With the SiNx dielectric, every electrical parameter including mobility, threshold voltage shift, and subthreshold characteristics is enhanced by 02 plasma treatment. Our experimental results demonstrate that interface engineering treatments variously influence the electrical performance in solution-processed ZnO TFTs.

  13. Proposed inductive voltage adder based accelerator concepts for the second axis of DARHT

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.L.; Johnson, D.L.; Boyes, J.D. [and others


    As participants in the Technology Options Study for the second axis of the Dual Axis Radiographic HydroTest (DARHT) facility located at Los Alamos National Laboratories, the authors have considered several accelerator concepts based on the Inductive Voltage Adder (IVA) technology that is being used successfully at Sandia on the SABRE and HERMES-III facilities. The challenging accelerator design requirements for the IVA approach include: {ge}12-MeV beam energy; {approximately}60-ns electrical pulse width; {le}40-kA electron beam current; {approximately}1-mm diameter e-beam; four pulses on the same axis or as close as possible to that axis; and an architecture that fits within the existing building envelope. To satisfy these requirements the IVA concepts take a modular approach. The basic idea is built upon a conservative design for eight ferromagnetically isolated 2-MV cavities that are driven by two 3 to 4-{Omega} water dielectric pulse forming lines (PFLs) synchronized with laser triggered gas switches. The 100-{Omega} vacuum magnetically insulated transmission line (MITL) would taper to a needle cathode that produces the electron beam(s). After considering many concepts the authors narrowed their study to the following options: (A) Four independent single pulse drivers powering four single pulse diodes; (B) Four series adders with interleaved cavities feeding a common MITL and diode; (C) Four stages of series PFLs, isolated from each other by triggered spark gap switches, with single-point feeds to a common adder, MITL, and diode; and (D) Isolated PFLs with multiple-feeds to a common adder using spark gap switches in combination with saturable magnetic cores to isolate the non-energized lines. The authors will discuss these options in greater detail identifying the challenges and risks associated with each.

  14. Low Voltage Electrowetting on Ferroelectric PVDF-HFP Insulator with Highly Tunable Contact Angle Range. (United States)

    Sawane, Yogesh B; Ogale, Satishchandra B; Banpurkar, Arun G


    We demonstrate a consistent electrowetting response on ferroelectric poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) insulator covered with a thin Teflon AF layer. This bilayer exhibits a factor of 3 enhancement in the contact angle modulation compared to that of conventional single-layered Teflon AF dielectric. On the basis of the proposed model the enhancement is attributed to the high value of effective dielectric constant (εeff ≈ 6) of the bilayer. Furthermore, the bilayer dielectric exhibits a hysteresis-free contact angle modulation over many AC voltage cycles. But the contact angle modulation for DC voltage shows a hysteresis because of the field-induced residual polarization in the ferroelectric layer. Finally, we show that a thin bilayer exhibits contact angle modulation of Δθ (U) ≈ 60° at merely 15 V amplitude of AC voltage indicating a potential dielectric for practical low voltage electrowetting applications. A proof of concept confirms electrowetting based rapid mixing of a fluorescent dye in aqueous glycerol solution for 15 V AC signal.

  15. Design Comparison of Autonomous High Voltage Driving System for DEAP Actuator

    DEFF Research Database (Denmark)

    Huang, Lina; Pittini, Riccardo; Zhang, Zhe


    As a new type of smart material, the Dielectric Electro Active Polymer (DEAP) is introduced in terms of configuration, working principle and potential applications. The design of an autonomous high voltage driving system for DEAP actuator is investigated. The system configuration and the design...

  16. Voltage Regulator for a dc-to-dc Converter (United States)

    Mclyman, C. W.


    New voltage regulator isolates signals from power-switching converter without use of complex circuitry or optical couplers. Only addition is extra secondary winding on existing interstage transformer. Error signals shortcircuit new winding and inhibit converter action. Resistor in series with primary winding limits short-circuit current to prevent damage to circuit components. Extra transformer winding eliminates need for isolation components.


    Directory of Open Access Journals (Sweden)

    Grigorash O. V.


    Full Text Available A promising is currently the use of asynchronous generators with capacitive excitation as a source of electricity in stand-alone power systems. Drive asynchronous generators may exercise as a thermal engine and wind wheel wind power plant or turbines of small hydropower plants. The article discusses the structural and schematics of voltage stabilizers and frequency of asynchronous generators with improved operational and technical specifications. Technical novelty of design solutions of the magnetic system and stabilizers asynchronous generator of electricity parameters confirmed by the patents for the invention of the Russian Federation. The proposed technical solution voltage stabilizer asynchronous generators, can reduce the weight of the block capacitors excitation and reactive power compensation, as well as to simplify the control system power circuit which has less power electronic devices. For wind power plants it is an important issue not only to stabilize the voltage of the generator, but also the frequency of the current. Recommend functionality stabilizer schemes parameters of electric power made for direct frequency converters with artificial and natural switching power electronic devices. It is also proposed as part of stabilization systems use single-phase voltage, three-phase transformers with rotating magnetic field, reduce the level of electromagnetic interference generated by power electronic devices for switching, enhance the efficiency and reliability of the stabilizer.

  18. Geomagnetism and Induced Voltage (United States)

    Abdul-Razzaq, W.; Biller, R. D.


    Introductory physics laboratories have seen an influx of "conceptual integrated science" over time in their classrooms with elements of other sciences such as chemistry, biology, Earth science, and astronomy. We describe a laboratory to introduce this development, as it attracts attention to the voltage induced in the human brain as it…

  19. High-voltage picoamperemeter

    Energy Technology Data Exchange (ETDEWEB)

    Bugl, Andrea; Ball, Markus; Boehmer, Michael; Doerheim, Sverre; Hoenle, Andreas; Konorov, Igor [Technische Universitaet Muenchen, Garching (Germany); Ketzer, Bernhard [Technische Universitaet Muenchen, Garching (Germany); Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)


    Current measurements in the nano- and picoampere region on high voltage are an important tool to understand charge transfer processes in micropattern gas detectors like the Gas Electron Multiplier (GEM). They are currently used to e.g. optimize the field configuration in a multi-GEM stack to be used in the ALICE TPC after the upgrade of the experiment during the 2nd long shutdown of the LHC. Devices which allow measurements down to 1pA at high voltage up to 6 kV have been developed at TU Muenchen. They are based on analog current measurements via the voltage drop over a switchable shunt. A microcontroller collects 128 digital ADC values and calculates their mean and standard deviation. This information is sent with a wireless transmitting unit to a computer and stored in a root file. A nearly unlimited number of devices can be operated simultaneously and read out by a single receiver. The results can also be displayed on a LCD directly at the device. Battery operation and the wireless readout are important to protect the user from any contact to high voltage. The principle of the device is explained, and systematic studies of their properties are shown.

  20. Universal trench design method for a high-voltage SOI trench LDMOS

    Institute of Scientific and Technical Information of China (English)

    Hu Xiarong; Zhang Bo; Luo Xiaorong; Li Zhaoji


    The design method for a high-voltage SOl trench LDMOS for various trench permittivities,widths and depths is introduced.A universal method for efficient design is presented for the first time,taking the trade-off between breakdown voltage (BV) and specific on-resistance (Rs,on) into account.The high-k (relative permittivity)dielectric is suitable to fill a shallow and wide trench while the low-k dielectric is suitable to fill a deep and narrow trench.An SOI LDMOS with a vacuum trench in the drift region is also discussed.Simulation results show that the high FOM BV2/Rs,on can be achieved with a trench filled with the low-k dielectric due to its shortened cell-pitch.

  1. Effect of Frequency on Emission of XeIast Excimer in a Pulsed Dielectric Barrier Discharge (United States)

    Ou, Qiong-Rong; Meng, Yue-Dong; Xu, Xu; Shu, Xing-Sheng; Ren, Zhao-Xing


    Emission spectra of XeIast excimers and ultraviolet intensity at 253 nm from a dielectric barrier discharge (DBD) lamp excited by a pulsed voltage were measured as functions of pressure, electrical power, and frequency. In the DBD lamp driven by a higher frequency voltage, a more intense emission of XeIast excimers with high efficiency at 253 nm was found. A diffuse discharge mode was observed at high xenon pressure (>1 atm) with an excessive iodine concentration in the DBD driven by a high frequency (60 kHz) voltage.

  2. Effect of Frequency on Emission of XeI* Excimer in a Pulsed Dielectric Barrier Discharge

    Institute of Scientific and Technical Information of China (English)

    OU Qiong-Rong; MENG Yue-Dong; XU Xu; SHU Xing-Sheng; REN Zhao-Xing


    Emission spectra of XeI* excimers and ultraviolet intensity at 253 nm from a dielectric barrier discharge (DBD)lamp excited by a pulsed voltage were measured as functions of pressure, electrical power, and frequency. In the DBD lamp driven by a higher frequency voltage, a more intense emission of XeI* excimers with high efficiency at 253 nm was found. A diffuse discharge mode was observed at high xenon pressure (> 1 atm) with an excessive iodine concentration in the DBD driven by a high frequency (60 kHz) voltage.

  3. Ionic mobility in DNA films studied by dielectric spectroscopy. (United States)

    Kahouli, Abdelkader; Valle-Orero, Jessica; Garden, Jean-Luc; Peyrard, Michel


    Double-helix DNA molecules can be found under different conformational structures driven by ionic and hydration surroundings. Usually, only the B-form of DNA, which is the only form stable in aqueous solution, can be studied by dielectric measurements. Here, the dielectric responses of DNA molecules in the A- and B-form, oriented co-linearly within fibres assembled in a film have been analyzed. The dielectric dispersion, permittivity and dissipation factor, have been measured as a function of frequency, strength voltage, time, temperature and nature of the counter-ions. Besides a high electrode polarization component, two relaxation peaks have been observed and fitted by two Cole-Cole relaxation terms. In the frequency range that we investigated (0.1 Hz to 5 ·10(6) Hz) the dielectric properties are dominated by the mobility and diffusivity of the counter-ions and their interactions with the DNA molecules, which can therefore be characterized for the A- and B-forms of DNA.


    Institute of Scientific and Technical Information of China (English)



    With the development of ultralarge scale integrated circuit, new interlayer dielectrics with low dielectric constant for multilevel interconnections are required, instead of conventional SiO2 films. For the sake of seeking perfect dielectrics, amorphous fluoropolymer (AF) thin film with a thickness of about 0.9μm has been prepared by spin-coating method, following the principle of phase separation. By capacitance-voltage (C-V) measurements the dielectric constant of the thin film is equal to 1.57 at 1 MHz, which is attributed to numerous pores contained in the film matrix. X-ray photoelectron spectroscopy (XPS) spectra show that after annealing, about 71% CFa groups in the AF film have decomposed into CF2, CF, etc. This leads to the increase of CF2 groups by three times and CF groups by 8% in the AF film. In a word, compared with the film without being annealed, about 25% carbon, 7% fluorine and 12% oxygen atoms will be lost after annealing at 400℃ for 30min.

  5. The Effect of Dielectric Barrier Discharge Plasma Treatment on the Microorganisms Found in Raw Cow’s Milk


    Aslan, Yakup


    Milk is an essential source of nutrition especially for the breastfed infants. Sterilization of milk is necessary because it can be contaminated by microorganisms due to unhygienic collection and storage conditions. In this study, the sterilization of raw cow milk was performed by using dielectric barrier discharge (DBD) plasma method. Raw milk was transferred to the plasma reactor and dielectric barrier discharge cold plasma was performed by changing various parameters including voltage, exp...

  6. Development of an open-ended microstrip stub apparatus and technique for the dielectric characterization of powders


    Sandhu, MY; Hunter, IC; Roberts, NS


    A new apparatus and method to characterize the complex dielectric permittivity of powders is described. The apparatus and technique are used to determine the dielectric properties of detergent powder agglomerates at different conditions. The technique is based on the measurement of Scattering-parameters of an open circuit microstrip stub partly loaded with the test powder material. The scattering parameters relate the voltage waves incident on the ports of a microwave network to those reflect...

  7. Complex Amorphous Dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    van Dover, Robert Bruce [Cornell Univ., Ithaca, NY (United States)


    This work focused on synthesizing a wide range of oxides containing two or more metals, and measuring their properties. Many simple metal oxides such as zirconium oxide, have been extensively studied in the past. We developed a technique in which we create a large number of compositions simultaneously and examine their behavior to understand trends and identify high performance materials. Superior performance generally comes in the form of increased responsiveness; in the materials we have studied this may mean more electrical charge for a given voltage in a capacitor, faster switching for a given drive in a transistor, more current for a given voltage in an ionic conductor, or more current for a given illumination in a solar cell. Some of the materials we have identified may find use in decreasing the power needed to operate integrated circuits, other materials could be useful for solar power or other forms of energy conversion.

  8. Hydrodynamical flows in dielectric liquid in strong inhomogeneous pulsed electric field (United States)

    Tereshonok, Dmitry V.; Babaeva, Natalia Yu; Naidis, George V.; Smirnov, Boris M.


    We consider a hydrodynamical flow of dielectric liquid near a high voltage needle-shaped electrode in a strong inhomogeneous pulsed electric field. It was shown that under a small rise time, a negative pressure area (pressure is less than critical pressure) appears near the electrode leading to the formation of a cavity in which electric breakdown can develop. A comparison of the dependence of the velocity of fluid near an electrode for two cases (taking into account the dependence of dielectric permeability of the liquid on the electric field and without taking it into account) was made. A field-dependent dielectric coefficient leads to the appearance of two local maximums of the velocities and increases the minimum pressure, thus lowering the possibility of cavitation. While under the constant value of dielectric permeability only one local maximum appears.

  9. Electric field dependent dielectric response of alumina/silicone oil colloids (United States)

    Magallon, Louis; Tsui, Stephen


    We investigate the dielectric response of a mixture of alumina nanopowder and silicone oil. Frequency and electric field dependent measurements of another insulating colloid, i.e., urea-coated Ba0.8Rb0.4TiO(C2O4)2 nanoparticles immersed in silicone oil, revealed universal dielectric response (UDR) characteristics and, with the application of high voltage, a negative capacitance. Alumina in silicone oil represents a simpler system in which to perform similar dielectric investigation. This colloid is sandwiched in a parallel plate capacitor cell, and the complex impedance is measured via lock-in amplifier at various frequencies and applied dc biases. Furthermore, we will compare and discuss the dielectric behaviors of different sized suspended alumina particles.

  10. Dielectric response of capacitor structures based on PZT annealed at different temperatures (United States)

    Kamenshchikov, Mikhail V.; Solnyshkin, Alexander V.; Pronin, Igor P.


    Dielectric response of thin-film capacitor structures of Pt/PZT/Pt deposited by the RF magnetron sputtering method and annealed at temperatures of 540-570 °C was investigated. It was found that dielectric properties of these structures depend on the synthesis temperature. Stability of a polarized state is considered on the basis of the analysis of hysteresis loops and capacitance-voltage (C-V) characteristics. The contribution of the domain mechanism in the dielectric response of the capacitor structure comprising a ferroelectric is discussed. Extreme dependences of electrophysical characteristics of PZT films on their synthesis temperature were observed. Correlation of dielectric properties with microstructure of these films is found out.

  11. Performance of pentacene-based organic field effect transistors using different polymer gate dielectrics

    Institute of Scientific and Technical Information of China (English)

    WU Ren-lei; CHENG Xiao-man; ZHENG Hong; YIN Shou-gen


    Pentacene-based organic field effect transistors (OFETs) are fabricated using poly(methyl methacrylate) (PMMA) and polyimide (PI) as gate dielectrics, respectively. The fabricated OFETs exhibit reasonable device characteristics. The field-effect mobility, threshold voltage, and on/off current radio are determined to be 3.214 × 10-2 cm2 / Vs, -28 V, and 1 × 103 respectively for OFETs with PMMA as gate dielectrics, and 7.306×10-3cm2 / Vs, -21 V, and 2 ×102 for OFETs with PI. Furthermore, the dielectric properties of gate insulator layer are tested and the dipole effect at the semiconductor/dielectrics interface is also analyzed by a model of energy level diagram.

  12. Dielectric Properties of Dy2O3 -Doped ( Ba, Sr) TiO3 Ceramics

    Institute of Scientific and Technical Information of China (English)

    Huang Xinyou; Gao Chunhua; Chen Xiangchong; Zheng Xialian; Huang Guojun; Liu Huiping


    The effects of Dy2O3 doping on the dielectric properties of (Ba, Sr)TiO3 series capacitor ceramics prepared using solid-state reaction method were studied. With the increasing of Dy2O3 additive , the dielectric constant (ε) of materials increases to a maximum when w(Dy2O3 ) is about 0.5% ,while the dielectric loss(tanδ) decreases. The BST ceramics with highε ( = 5245 ), low tanδ ( = 0. 0026 ) and high DC breakdown voltage ( = 5.5 mV ·m-1 ) were obtained. The influencing mechanism of Dy2O3 on the dielectric properties of (Ba, Sr)TiO3 ceramics was studied, thus providing the basis for preparation of capacitor ceramics.

  13. Polymer thin-film transistor based on a high dielectric constant gate insulator

    Institute of Scientific and Technical Information of China (English)

    Lü Wen; Peng Jun-Biao; Yang Kai-Xia; Lan Lin-Feng; Niu Qiao-Li; Cao Yong


    In this paper full polymer thin-film transistors (PTFTs) based on Poly (acrylonitrile) (PAN) as the gate dielectric and poly (2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene-vinylene) (MEH-PPV) as the semiconductor layer were investigated by using different channel width/length ratios. Relatively high dielectric constant of the polymer dielectric layer (6.27) can remarkably reduce the threshold voltage of the transistors to below-3 V. Hole field-effect mobility of MEH-PPV of the PTFTs was about 4.8 × 10-4 cm2/Vs, and on/off current ratio was larger than 102, which was comparable with that of transistors with widely used Poly (4-vinyl phenol) (PVP) or SiO2 as gate dielectrics.

  14. Microwave Dielectric Heating of Drops in Microfluidic Devices

    CERN Document Server

    Issadore, David; Brown, Keith A; Sandberg, Lori; Weitz, David; Westervelt, Robert M


    We present a technique to locally and rapidly heat water drops in microfluidic devices with microwave dielectric heating. Water absorbs microwave power more efficiently than polymers, glass, and oils due to its permanent molecular dipole moment that has a large dielectric loss at GHz frequencies. The relevant heat capacity of the system is a single thermally isolated picoliter drop of water and this enables very fast thermal cycling. We demonstrate microwave dielectric heating in a microfluidic device that integrates a flow-focusing drop maker, drop splitters, and metal electrodes to locally deliver microwave power from an inexpensive, commercially available 3.0 GHz source and amplifier. The temperature of the drops is measured by observing the temperature dependent fluorescence intensity of cadmium selenide nanocrystals suspended in the water drops. We demonstrate characteristic heating times as short as 15 ms to steady-state temperatures as large as 30 degrees C above the base temperature of the microfluidi...

  15. High Voltage Bidirectional Flyback Converter Driving DEAP Actuator for Automotive Applications

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.;


    DEAP (Dielectric Electro Active Polymer) is a new type of smart material. The actuator based on DEAP material tends to be applied in a variety of occasions. It will have prosperous future when employed in automotive field. This paper is focused on the design and implementation of a low input volt...... voltage and high output voltage bidirectional converter for driving the DEAP actuator. The detailed design and implemented parameters have been summarized, especially for the high voltage transformer. The experiments have been performed to validate the design and implementation....

  16. Effects of surface dielectric barrier discharge on aerodynamic characteristic of train (United States)

    Dong, Lei; Gao, Guoqiang; Peng, Kaisheng; Wei, Wenfu; Li, Chunmao; Wu, Guangning


    High-speed railway today has become an indispensable means of transportation due to its remarkable advantages, including comfortability, convenience and less pollution. The increase in velocity makes the air drag become the main source of energy consumption, leading to receiving more and more concerns. The surface dielectric barrier discharge has shown some unique characteristics in terms of active airflow control. In this paper, the influences of surface dielectric barrier discharge on the aerodynamic characteristics of a scaled train model have been studied. Aspects of the discharge power consumption, the temperature distribution, the velocity of induced flow and the airflow field around the train model were considered. The applied AC voltage was set in the range of 20 kV to 28 kV, with a fixed frequency of 9 kHz. Results indicated that the discharge power consumption, the maximum temperature and the induced flow velocity increased with increasing applied voltage. Mechanisms of applied voltage influencing these key parameters were discussed from the point of the equivalent circuit. The airflow field around the train model with different applied voltages was observed by the smoke visualization experiment. Finally, the effects of surface dielectric barrier discharge on the train drag reduction with different applied voltages were analyzed.

  17. A novel variable stiffness mechanism for dielectric elastomer actuators (United States)

    Li, Wen-Bo; Zhang, Wen-Ming; Zou, Hong-Xiang; Peng, Zhi-Ke; Meng, Guang


    In this paper, a novel variable stiffness mechanism is proposed for the design of a variable stiffness dielectric elastomer actuator (VSDEA) which combines a flexible strip with a DEA in a dielectric elastomer minimum energy structure. The DEA induces an analog tuning of the transverse curvature of the strip, thus conveniently providing a voltage-controllable flexural rigidity. The VSDEA tends to be a fully flexible and compact structure with the advantages of simplicity and fast response. Both experimental and theoretical investigations are carried out to reveal the variable stiffness performances of the VSDEA. The effect of the clamped location on the bending stiffness of the VSDEA is analyzed, and then effects of the lengths, the loading points and the applied voltages on the bending stiffness are experimentally investigated. An analytical model is developed to verify the availability of this variable stiffness mechanism, and the theoretical results demonstrate that the bending stiffness of the VSDEA decreases as the applied voltage increases, which agree well with the experimental data. Moreover, the experimental results show that the maximum change of the relative stiffness can reach about 88.80%. It can be useful for the design and optimization of active variable stiffness structures and DEAs for soft robots, vibration control, and morphing applications.

  18. Efficiency of pulse-mode dielectric barrier discharge excimer lamp in constant duty cycle (United States)

    Akashi, Haruaki; Oda, Akinori; Sakai, Yosuke


    Efficiency of pulse-mode dielectric barrier discharge (DBD) excimer lamp under constant duty cycle with increasing applied voltage has been simulated using two dimensional fluid model[1]. Xe gas with 300Torr pressure is assumed. And the simulated region considered in this model is 1cm(gap length)x3cm(radial length). Periodical boundary conditions are assumed for the radial direction boundaries. The both electrodes are covered with dielectrics and their thickness is 0.2cm. 5˜8kV trapezoid shape voltage is applied with the same voltage rising ratio and 50% duty ratio waveform with 200x10^3pps repetition rate. The discharge occurs at the rising edge and tailing edge of applied voltage. 172nm VUV intensity obtained from first discharge is higher than second one in lower applied voltage (<6kV) case. And in higher voltage case, the intensity from second discharge becomes higher. This is explained by shortening of interval time between the discharges. The short interval time makes higher initial electron density for second discharge. As a results, the input and 172nm VUV output power increases with increasing applied voltage, but the efficiency decreases. Because of inefficient surface discharge [1]H. Akashi et al, IEEE Trans. Plasma Science, Vol.33,No.2(2005,4)pp.308-309

  19. A Comparison of Dielectric Properties of Palm Oil with Mineral and Synthetic Types Insulating Liquid under Temperature Variation

    Directory of Open Access Journals (Sweden)

    Abdul Rajab


    Full Text Available Mineral oil is known to have a low biodegradability level and high susceptibility to the fire. These conditions motivate many researchers to look for alternative sources for insulating oil. One of the alternative liquid is palm oil. To verify the suitability of using palm oil as an insulating liquid, it is important to make dielectric properties comparison with the commonly used insulating liquid. This paper presents comparison of temperature effect on dielectric properties of palm oil with mineral type insulating liquid and silicone oil. The measured parameters were breakdown voltage, dissipation factor (tan δ, and dielectric constant. Breakdown voltage measurement was performed in accordance with IEC 156 standard, whereas, the dissipation factor and dielectric constant measurement were conducted based on IEC 60247 standard test methods. The results showed that variations of dielectric properties of palm oil to the temperature change, in general, have the same tendency with those of commonly used insulating liquids i.e. mineral oil and silicone oil. Breakdown voltages and dissipation factors of all tested oils were increased, while their dielectric constants were slightly decreased with the increase of temperature.

  20. Flexible Dielectric Nanocomposites with Ultrawide Zero-Temperature Coefficient Windows for Electrical Energy Storage and Conversion under Extreme Conditions. (United States)

    Shehzad, Khurram; Xu, Yang; Gao, Chao; Li, Hanying; Dang, Zhi-Min; Hasan, Tawfique; Luo, Jack; Duan, Xiangfeng


    Polymer dielectrics offer key advantages over their ceramic counterparts such as flexibility, scalability, low cost, and high breakdown voltages. However, a major drawback that limits more widespread application of polymer dielectrics is their temperature-dependent dielectric properties. Achieving dielectric constants with low/zero-temperature coefficient (L/0TC) over a broad temperature range is essential for applications in diverse technologies. Here, we report a hybrid filler strategy to produce polymer composites with an ultrawide L/0TC window of dielectric constant, as well as a significantly enhanced dielectric value, maximum energy storage density, thermal conductivity, and stability. By creating a series of percolative polymer composites, we demonstrated hybrid carbon filler based composites can exhibit a zero-temperature coefficient window of 200 °C (from -50 to 150 °C), the widest 0TC window for all polymer composite dielectrics reported to date. We further show the electric and dielectric temperature coefficient of the composites is highly stable against stretching and bending, even under AC electric field with frequency up to 1 MHz. We envision that our method will push the functional limits of polymer dielectrics for flexible electronics in extreme conditions such as in hybrid vehicles, aerospace, power electronics, and oil/gas exploration.

  1. Atmospheric pressure dielectric barrier discharges for sterilization and surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chin, O. H.; Lai, C. K.; Choo, C. Y.; Wong, C. S.; Nor, R. M. [Plasma Technology Research Centre, Physics Department, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Thong, K. L. [Microbiology Division, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)


    Atmospheric pressure non-thermal dielectric barrier discharges can be generated in different configurations for different applications. For sterilization, a parallel-plate electrode configuration with glass dielectric that discharges in air was used. Gram-negative bacteria (Escherichia coli and Salmonella enteritidis) and Gram-positive bacteria (Bacillus cereus) were successfully inactivated using sinusoidal high voltage of ∼15 kVp-p at 8.5 kHz. In the surface treatment, a hemisphere and disc electrode arrangement that allowed a plasma jet to be extruded under controlled nitrogen gas flow (at 9.2 kHz, 20 kVp-p) was applied to enhance the wettability of PET (Mylar) film.

  2. Non-linear dielectric monitoring of biological suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Treo, E F; Felice, C J [Departamento de BioingenierIa, Universidad Nacional de Tucuman and Consejo Nacional de Investigaciones Cientificas y Tecnicas. CC327, CP4000, San Miguel de Tucuman (Argentina)


    Non-linear dielectric spectroscopy as a tool for in situ monitoring of enzyme assumes a non-linear behavior of the sample when a sinusoidal voltage is applied to it. Even many attempts have been made to improve the original experiments, all of them had limited success. In this paper we present upgrades made to a non-linear dielectric spectrometer developed and the results obtained when using different cells. We emphasized on the electrode surface, characterizing the grinding and polishing procedure. We found that the biological medium does not behave as expected, and the non-linear response is generated in the electrode-electrolyte interface. The electrochemistry of this interface can bias unpredictably the measured non-linear response.

  3. High-frequency graphene voltage amplifier. (United States)

    Han, Shu-Jen; Jenkins, Keith A; Valdes Garcia, Alberto; Franklin, Aaron D; Bol, Ageeth A; Haensch, Wilfried


    While graphene transistors have proven capable of delivering gigahertz-range cutoff frequencies, applying the devices to RF circuits has been largely hindered by the lack of current saturation in the zero band gap graphene. Herein, the first high-frequency voltage amplifier is demonstrated using large-area chemical vapor deposition grown graphene. The graphene field-effect transistor (GFET) has a 6-finger gate design with gate length of 500 nm. The graphene common-source amplifier exhibits ∼5 dB low frequency gain with the 3 dB bandwidth greater than 6 GHz. This first AC voltage gain demonstration of a GFET is attributed to the clear current saturation in the device, which is enabled by an ultrathin gate dielectric (4 nm HfO(2)) of the embedded gate structures. The device also shows extrinsic transconductance of 1.2 mS/μm at 1 V drain bias, the highest for graphene FETs using large-scale graphene reported to date.

  4. Self-organized plasmas formed by accumulated charge in dielectric barrier discharge (United States)

    Akashi, Haruaki; Yoshinaga, Tomokazu


    Atmospheric pressure dielectric barrier discharges (DBDs) have been widely applied to various research fields, such as bio-medical treatment, toxic decomposition and so on. However, the details of DBD have not been understood yet. Because the phenomena occur in nanosecond time scale under atmospheric pressure. It is known that DBDs are significantly affected by accumulated charges on dielectrics, but the distributions and development of accumulated charges are not known for years. To clarify the distributions and the developments of accumulated charges on dielectrics and electron behavior in the vicinity of dielectrics, DBDs in atmospheric pressure oxygen have been simulated using a two dimensional fluid model with relatively high electron emission coefficient. In this condition, DBD simulation results are obtained in so called self-organized form. As a result, the locations of highly accumulated charges are at where the primary streamers reached in a half cycle. And the charges on the dielectrics become almost zero by the electrons after the change of discharge voltage polarity. The electron distribution in the vicinity of the dielectric forms similar to that of accumulated charges to compensate the charges. Excess electrons in front of dielectric become the seed electrons for next half cycle. This continuation makes discharge in self-organized form.

  5. Statistical modelling of discharge behavior of atmospheric pressure dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Tay, W. H.; Kausik, S. S.; Wong, C. S., E-mail:; Yap, S. L.; Muniandy, S. V. [Plasma Technology Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)


    In this work, stochastic behavior of atmospheric pressure dielectric barrier discharge (DBD) has been investigated. The experiment is performed in a DBD reactor consisting of a pair of stainless steel parallel plate electrodes powered by a 50 Hz ac high voltage source. Current pulse amplitude distributions for different space gaps and the time separation between consecutive current pulses are studied. A probability distribution function is proposed to predict the experimental distribution function for the current pulse amplitudes and the occurrence of the transition regime of the pulse distribution. Breakdown voltage at different positions on the dielectric surface is suggested to be stochastic in nature. The simulated results based on the proposed distribution function agreed well with the experimental results and able to predict the regime of transition voltage. This model would be useful for the understanding of stochastic behaviors of DBD and the design of DBD device for effective operation and applications.

  6. Study of a Modified AC Bridge Technique for Loss Angle Measurement of a Dielectric Material

    Directory of Open Access Journals (Sweden)

    S. C. BERA


    Full Text Available A Wheatstone’s bridge network like Schering Bridge, DeSauty Bridge etc measures the loss angle or tangent of loss angle (tanδ of a dielectric material. In high voltage application this loss angle is generally measured by high voltage Schering Bridge. But continuous measurement of tan δ is not possible by these techniques. In the present paper a modified operational amplifiers based Schering Bridge network has been proposed for continuous measurement of tanδ in the form of a bridge network output voltage. Mathematical analysis of the proposed bridge network has been discussed in the paper and experimental work has been performed assuming the lossy dielectric material as a series combination of loss less capacitor and a resistor. Experimental results are reported in the paper. From the mathematical analysis and experimental results it is found that the output of the proposed bridge network is almost linearly related with tanδ.

  7. Theoretical analysis of ozone generation by pulsed dielectric barrier discharge in oxygen (United States)

    Wei, L. S.; Zhou, J. H.; Wang, Z. H.; Cen, K. F.


    The use of very short high-voltage pulses combined with a dielectric layer results in high-energy electrons that dissociate oxygen molecules into atoms, which are a prerequisite for the subsequent production of ozone by collisions with oxygen molecules and third particles. The production of ozone depends on both the electrical and the physical parameters. For ozone generation by pulsed dielectric barrier discharge in oxygen, a mathematical model, which describes the relation between ozone concentration and these parameters that are of importance in its design, is developed according to dimensional analysis theory. A formula considering the ozone destruction factor is derived for predicting the characteristics of the ozone generation, within the range of the corona inception voltage to the gap breakdown voltage. The trend showing the dependence of the concentration of ozone in oxygen on these parameters generally agrees with the experimental results, thus confirming the validity of the mathematical model.

  8. Dielectric screening in semiconductors (United States)

    Harrison, Walter A.; Klepeis, John E.


    Intra-atomic and interatomic Coulomb interactions are incorporated into bond-orbital theory, based upon universal tight-binding parameters, in order to treat the effects of charge redistribution in semiconductor bonds. The dielectric function ɛ(q) is obtained for wave numbers in a [100] direction. The screening of differences in average hybrid energy across a heterojunction is calculated in detail, indicating that the decay length for the potential depends upon the relative values of Madelung and intra-atomic Coulomb terms. The parameters used here predict an imaginary decay length and thus an oscillating potential near the interface. The same theory is applied to point defects by imbedding a cluster in a matrix lattice, taking charges in that lattice to be consistent with continuum theory. Illustrating the theory with a phosphorus impurity in silicon, it is seen that the impurity and its neighboring atoms have charges on the order of only one-tenth of an electronic charge, alternating in sign from neighbor to neighbor as for planar defects. Although there are shifts in the term values on the order of a volt, the difference in these shifts for neighboring atoms is much smaller so that the effect on the bonds is quite small. This behavior is analogous to the response of a dielectric continuum to a point charge: The medium is locally neutral except at the center of the cluster and there are slowly varying potentials e2/ɛr. Because of this slow variation, free-atom term values should ordinarily suffice for the calculation of bond properties and bond lengths at impurities. Corrections are larger for homovalent substitutions such as carbon in silicon.

  9. Nanocomposites of polyimide and mixed oxide nanoparticles for high performance nanohybrid gate dielectrics in flexible thin film transistors (United States)

    Kim, Ju Hyun; Hwang, Byeong-Ung; Kim, Do-Il; Kim, Jin Soo; Seol, Young Gug; Kim, Tae Woong; Lee, Nae-Eung


    Organic gate dielectrics in thin film transistors (TFTs) for flexible display have advantages of high flexibility yet have the disadvantage of low dielectric constant (low-k). To supplement low-k characteristics of organic gate dielectrics, an organic/inorganic nanocomposite insulator loaded with high-k inorganic oxide nanoparticles (NPs) has been investigated but high loading of high-k NPs in polymer matrix is essential. Herein, compositing of over-coated polyimide (PI) on self-assembled (SA) layer of mixed HfO2 and ZrO2 NPs as inorganic fillers was used to make dielectric constant higher and leakage characteristics lower. A flexible TFT with lower the threshold voltage and high current on/off ratio could be fabricated by using the hybrid gate dielectric structure of the nanocomposite with SA layer of mixed NPs on ultrathin atomic-layer deposited Al2O3.

  10. Comparative Study of Breakdown Voltage of Mineral, Synthetic and Natural Oils and Based Mineral Oil Mixtures under AC and DC Voltages

    Directory of Open Access Journals (Sweden)

    Abderrahmane Beroual


    Full Text Available This paper deals with a comparative study of AC and DC breakdown voltages of based mineral oil mixtures with natural and synthetic esters mainly used in high voltage power transformers. The goal was to analyze the performances of oil mixtures from the dielectric withstand point of view and to predict the behavior of transformers originally filled with mineral oil and re-filled with synthetic or natural ester oils when emptied for maintenance. The study concerns mixtures based on 20%, 50%, and 80% of natural and synthetic ester oils. AC breakdown voltages were measured using a sphere-sphere electrode system according to IEC 60156 specifications; the same specification was adopted for DC measurements since there is no standard specifications for this voltage waveform. A statistical analysis of the mean values, standard deviations, and histograms of breakdown voltage data was carried out. The Normal and Weibull distribution functions were used to analyze the experimental data and the best function that the data followed was used to estimate the breakdown voltage with risk of 1%, 10%, and 50% probability. It was shown that whatever the applied voltage waveforms, ester oils always have a significantly higher breakdown voltage than mineral oil. The addition of only 20% of natural or synthetic ester oil was sufficient to considerably increase the breakdown voltage of mineral oil. The dielectric strength of such a mixture is much higher than that of mineral oil alone and can reach that of ester oils. From the point of view of dielectric strength, the mixtures constitute an option for improving the performance of mineral oil. Thus, re-filling of transformers containing up to 20% mineral oil residues with ester oils, does not present any problem; it is even advantageous when considering only the breakdown voltage. Under AC, the mixtures with natural ester always follow the behavior of vegetable oil alone. With the exception of the 20% mixture of natural

  11. Deployment of low-voltage regulator considering existing voltage control in medium-voltage distribution systems

    Directory of Open Access Journals (Sweden)

    Hiroshi Kikusato


    Full Text Available Many photovoltaic (PV systems have been installed in distribution systems. This installation complicates the maintenance of all voltages within the appropriate range in all low-voltage distribution systems (LVDSs because the trends in voltage fluctuation differ in each LVDS. The installation of a low-voltage regulator (LVR that can accordingly control the voltage in each LVDS has been studied as a solution to this problem. Voltage control in a medium-voltage distribution system must be considered to study the deployment of LVRs. In this study, we installed LVRs in the LVDSs in which the existing voltage-control scheme cannot prevent voltage deviation and performed a numerical simulation by using a distribution system model with PV to evaluate the deployment of the LVRs.

  12. Tunable dielectric properties of ferrite-dielectric based metamaterial.

    Directory of Open Access Journals (Sweden)

    K Bi

    Full Text Available A ferrite-dielectric metamaterial composed of dielectric and ferrite cuboids has been investigated by experiments and simulations. By interacting with the electromagnetic wave, the Mie resonance can take place in the dielectric cuboids and the ferromagnetic precession will appear in the ferrite cuboids. The magnetic field distributions show the electric Mie resonance of the dielectric cuboids can be influenced by the ferromagnetic precession of ferrite cuboids when a certain magnetic field is applied. The effective permittivity of the metamaterial can be tuned by modifying the applied magnetic field. A good agreement between experimental and simulated results is demonstrated, which confirms that these metamaterials can be used for tunable microwave devices.

  13. Dielectric Spectroscopy Analyses of SrBi4Ti4O15 Films Obtained from Soft Chemical Solution

    Directory of Open Access Journals (Sweden)

    A. Z. Simões


    Full Text Available SrBi4Ti4O15 (SBTi thin films were deposited by the polymeric precursor method on Pt bottom electrodes. The obtained films were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and dielectric spectroscopy analyses. The capacitance-voltage (C-V characteristics of perovskite thin film showed normal ferroelectric behavior. The remanent polarization and coercive fields were 5.4 μC/cm2 and 85 kV/cm, respectively. Dielectric spectroscopy was employed to examine the polycrystalline behavior of ferroelectric material and the mechanisms responsible for the dielectric performance of the thin film.

  14. Analyzing of Dynamic Voltage Restorer in Series Compensation Voltage

    Directory of Open Access Journals (Sweden)

    Naser Parhizgar


    Full Text Available The Dynamic Voltage Restorer (DVR is a series-connected compensator to generate a controllable voltage to against the short-term voltage disturbances. The technique of DVR is an effective and cost competitive approach to improve voltage quality at the load side. This study presents a single-phase and threephase DVR system with reduced switch-count topology to protect the sensitive load against abnormal voltage conditions. Most basic function, the DVR configuration consist of a two level Voltage Source Converter (VSC, a dc energy storage device, a coupling transformer Connected in shunt with the ac system This study presents the application of Dynamic Voltage Restorer (DVR on power distribution systems for mitigation of voltage sag at critical loads. DVR is one of the compensating types of custom power devices. The DVR, which is based on forced-commutated Voltage Source Converter (VSC has been proved suitable for the task of compensating voltage sags/swells. Simulation results are presented to illustrate and understand the performances of DVR in supporting load voltages under voltage sags/swells conditions.

  15. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.


    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  16. Triple voltage dc-to-dc converter and method (United States)

    Su, Gui-Jia


    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  17. Depth Profiling of La2O3 ∕ HfO2 Stacked Dielectrics for Nanoelectronic Device Applications

    KAUST Repository

    Alshareef, Husam N.


    Nanoscale La2O3 /HfO2 dielectric stacks have been studied using high resolution Rutherford backscattering spectrometry. The measured distance of the tail-end of the La signal from the dielectric/Si interface suggests that the origin of the threshold voltage shifts and the carrier mobility degradation may not be the same. Up to 20% drop in mobility and 500 mV shift in threshold voltage was observed as the La signal reached the Si substrate. Possible reasons for these changes are proposed, aided by depth profiling and bonding analysis. © 2011 The Electrochemical Society.

  18. Increased voltage photovoltaic cell (United States)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)


    A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

  19. High Voltage Seismic Generator (United States)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin


    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  20. Towards all-dielectric metamaterials and nanophotonics

    CERN Document Server

    Krasnok, Alexander; Petrov, Mikhail; Savelev, Roman; Belov, Pavel; Kivshar, Yuri


    We review a new, rapidly developing field of all-dielectric nanophotonics which allows to control both magnetic and electric response of structured matter by engineering the Mie resonances in high-index dielectric nanoparticles. We discuss optical properties of such dielectric nanoparticles, methods of their fabrication, and also recent advances in all-dielectric metadevices including couple-resonator dielectric waveguides, nanoantennas, and metasurfaces.

  1. Mitigation of Voltage Sags in CIGRE Low Voltage Distribution Network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak-Jensen, Birgitte; Mahat, Pukar;


    problems in the distribution system. The voltage problems dealt with in this paper are to show how to mitigate voltage sags in the CIGRE Low Voltage (LV) test network and networks like this. The voltage sags, for the tested cases in the CIGRE LV test network are mainly due to three phase faults....... The compensation of voltage sags in the different parts of CIGRE distribution network is done by using the four STATCOM compensators already existing in the test grid. The simulations are carried out in DIgSILENT power factory software version 15.0....

  2. Dielectric inspection of erythrocyte morphology (United States)

    Hayashi, Yoshihito; Oshige, Ikuya; Katsumoto, Yoichi; Omori, Shinji; Yasuda, Akio; Asami, Koji


    We performed a systematic study of the sensitivity of dielectric spectroscopy to erythrocyte morphology. Namely, rabbit erythrocytes of four different shapes were prepared by precisely controlling the pH of the suspending medium, and their complex permittivities over the frequency range from 0.1 to 110 MHz were measured and analyzed. Their quantitative analysis shows that the characteristic frequency and the broadening parameter of the dielectric relaxation of interfacial polarization are highly specific to the erythrocyte shape, while they are insensitive to the cell volume fraction. Therefore, these two dielectric parameters can be used to differentiate erythrocytes of different shapes, if dielectric spectroscopy is applied to flow-cytometric inspection of single blood cells. In addition, we revealed the applicability and limitations of the analytical theory of interfacial polarization to explain the experimental permittivities of non-spherical erythrocytes.

  3. Electromagnetic identification of dielectric materials

    Directory of Open Access Journals (Sweden)

    A. F. Yanenko


    Full Text Available The electromagnetic features and parameters of dielectric materials, which are used in light industry and stomatology. The results of measuring are analyzed and the method of authentication is offered.

  4. Dielectric Spectroscopy in Biomaterials: Agrophysics

    Directory of Open Access Journals (Sweden)

    Dalia El Khaled


    Full Text Available Being dependent on temperature and frequency, dielectric properties are related to various types of food. Predicting multiple physical characteristics of agri-food products has been the main objective of non-destructive assessment possibilities executed in many studies on horticultural products and food materials. This review manipulates the basic fundamentals of dielectric properties with their concepts and principles. The different factors affecting the behavior of dielectric properties have been dissected, and applications executed on different products seeking the characterization of a diversity of chemical and physical properties are all pointed out and referenced with their conclusions. Throughout the review, a detailed description of the various adopted measurement techniques and the mostly popular equipment are presented. This compiled review serves in coming out with an updated reference for the dielectric properties of spectroscopy that are applied in the agrophysics field.

  5. Voltage Controlled Dynamic Demand Response

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Mahat, Pukar


    . An adaptive dynamic model has been developed to determine composite voltage dependency of an aggregated load on feeder level. Following the demand dispatch or control signal, optimum voltage setting at the LV substation is determined based on the voltage dependency of the load. Furthermore, a new technique...

  6. Charge-pump voltage converter (United States)

    Brainard, John P.; Christenson, Todd R.


    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  7. The statistics of the dielectric breakdown of thin films

    CERN Document Server

    Rowland, S M


    The statistics of the dielectric breakdown of thin films of silicon monoxide and aluminium oxide have been studied. The self healing technique which allows numerous breakdowns to be observed on one sample was employed. Ramp and steady state voltage experiments are reported and the limitations of these techniques are discussed. It is shown that the experimental data on breakdown can be fitted to two-parameter Weibull distributions using mixed distribution models. Methods have been developed to facilitate the evaluation of the associated parameters from results taken over limited time periods by graphical means. The significance of these parameters and the relationship between ramp and steady state testing techniques are discussed.

  8. Bound Modes in Dielectric Microcavities

    CERN Document Server

    Visser, P M; Lenstra, D


    We demonstrate how exactly bound cavity modes can be realized in dielectric structures other than 3d photonic crystals. For a microcavity consisting of crossed anisotropic layers, we derive the cavity resonance frequencies, and spontaneous emission rates. For a dielectric structure with dissipative loss and central layer with gain, the beta factor of direct spontaneous emission into a cavity mode and the laser threshold is calculated.

  9. Transient voltage sharing in series-coupled high voltage switches

    Directory of Open Access Journals (Sweden)

    Editorial Office


    Full Text Available For switching voltages in excess of the maximum blocking voltage of a switching element (for example, thyristor, MOSFET or bipolar transistor such elements are often coupled in series - and additional circuitry has to be provided to ensure equal voltage sharing. Between each such series element and system ground there is a certain parasitic capacitance that may draw a significant current during high-speed voltage transients. The "open" switch is modelled as a ladder network. Analy­sis reveals an exponential progression in the distribution of the applied voltage across the elements. Overstressing thus oc­curs in some of the elements at levels of the total voltage that are significantly below the design value. This difficulty is overcome by grading the voltage sharing circuitry, coupled in parallel with each element, in a prescribed manner, as set out here.

  10. Dielectric properties of Al2O3 coatings deposited via atmospheric plasma spraying and dry-ice blasting correlated with microstructural characteristics (United States)

    Dong, Shujuan; Song, Bo; Liao, Hanlin; Coddet, Christian


    In this work, atmospheric plasma spraying combined with dry-ice blasting have been used to prepare alumina (Al2O3) coatings designed for insulating applications. The microstructural characteristics and dielectric properties of Al2O3 coatings were presented. The electrical insulating properties, i.e., dielectric strength and breakdown voltage, were investigated by dielectric breakdown test using direct current and alternating current. Relationships between dielectric properties and coating characteristics were discussed. The results showed that dry-ice blasting used during atmospheric plasma spray process allowed the production of coatings with better dielectric properties than those prepared without dry-ice blasting. The dielectric properties were correlated with the microstructural characteristics, not with phase composition.

  11. Dielectric relaxation process of a partially unwound helical structure in ferroelectric liquid crystals. (United States)

    Choudhary, Amit; Bawa, Ambika; Rajesh; Singh, Surinder P; Biradar, Ashok M


    The fluctuations of unwound helical structure have been observed in deformed helix ferroelectric liquid crystal (DHFLC) and conventional FLC sample cells. The helix is partially unwound by strong anchoring on the substrates. In such sample cells, the helical decarlization lines are not observed in the texture under crossed polarized microscope. The dielectric spectroscopy is employed to observe the behavior of dielectric relaxation processes in these sample cells. A dielectric relaxation process is observed at a lower frequency than the Goldstone mode processes in DHFLC and FLC, which we call partially unwound helical mode (p-UHM). However, the p-UHM process is not observed in the sample cell in which the helical lines appear. The application of various amplitudes of probing ac voltages on this mode has shown the higher frequency shift, i.e., the larger the amplitude of ac voltage, the higher is the relaxation frequency of p-UHM. At sufficient amplitude of applied probing ac voltage, the p-UHM merges with the Goldstone mode process and is difficult to detect. However, the Goldstone mode relaxation frequency is almost independent of the cell geometry and sample configuration. The electro-optical behavior of the p-UHM has also been confirmed by electro-optical technique. The dielectric relaxation of UHM at a frequency lower than the Goldstone mode is interpreted as the fluctuation of partially unwound helix.

  12. The electro-mechanical phase transition of Gent model dielectric elastomer tube with two material constants (United States)

    Liu, Liwu; Luo, Xiaojian; Fei, Fan; Wang, Yixing; Leng, Jinsong; Liu, Yanju


    Applied to voltage, a dielectric elastomer membrane may deform into a mixture of two states under certain conditions. One of which is the flat state and the other is the wrinkled state. In the flat state, the membrane is relatively thick with a small area, while on the contrary, in the wrinkled state, the membrane is relatively thin with a large area. The coexistence of these two states may cause the electromechanical phase transition of dielectric elastomer. The phase diagram of idea dielectric elastomer membrane under unidirectional stress and voltage inspired us to think about the liquid-to-vapor phase transition of pure substance. The practical working cycle of a steam engine includes the thermodynamical process of liquid-to-vapor phase transition, the fact is that the steam engine will do the maximum work if undergoing the phase transition process. In this paper, in order to consider the influence of coexistent state of dielectric elastomer, we investigate the homogeneous deformation of the dielectric elastomer tube. The theoretical model is built and the relationship between external loads and stretch are got, we can see that the elastomer tube experiences the coexistent state before reaching the stretching limit from the diagram. We think these results can guide the design and manufacture of energy harvesting equipments.

  13. Effect of argon ion implantation on the electrical and dielectric properties of CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Chawla, Mahak, E-mail:; Shekhawat, Nidhi; Goyal, Meetika; Gupta, Divya; Sharma, Annu; Aggarwal, Sanjeev [Department of Physics, Kurukshetra University, Kurukshetra - 136119 (India)


    The objective of the present work is to study the effect of 130 keV Ar{sup +} ions on the electrical and dielectric properties of CR-39 samples at various doses 5×10{sup 14}, 1×10{sup 15} and 1×10{sup 16} Ar{sup +} cm{sup −2}. Current-Voltage (I-V characteristics) measurements have been used to study the electrical properties of virgin and Ar{sup +} implanted CR-39 specimens. The current has been found to be increased with increasing voltage as well as with increasing ion dose. The dielectric spectroscopy of these specimens has been done in the frequency range of 100 kHz-100 MHz. The dielectric constant has been found to be decreasing whereas dielectric loss factor increases with increasing ion fluence. These kind of behavior observed in the implanted specimens indicate towards the formation of carbonaceous clusters due to the cross linking, chemical bond cleavage, formation of free radicals. The changes observed in the dielectric behavior have been further correlated with the structural changes observed through I-V characteristics.

  14. Effect of argon ion implantation on the electrical and dielectric properties of CR-39 (United States)

    Chawla, Mahak; Shekhawat, Nidhi; Goyal, Meetika; Gupta, Divya; Sharma, Annu; Aggarwal, Sanjeev


    The objective of the present work is to study the effect of 130 keV Ar+ ions on the electrical and dielectric properties of CR-39 samples at various doses 5×1014, 1×1015 and 1×1016 Ar+ cm-2. Current-Voltage (I-V characteristics) measurements have been used to study the electrical properties of virgin and Ar+ implanted CR-39 specimens. The current has been found to be increased with increasing voltage as well as with increasing ion dose. The dielectric spectroscopy of these specimens has been done in the frequency range of 100 kHz-100 MHz. The dielectric constant has been found to be decreasing whereas dielectric loss factor increases with increasing ion fluence. These kind of behavior observed in the implanted specimens indicate towards the formation of carbonaceous clusters due to the cross linking, chemical bond cleavage, formation of free radicals. The changes observed in the dielectric behavior have been further correlated with the structural changes observed through I-V characteristics.

  15. Enhanced emission extraction and selective readout of NV centers with all-dielectric nanoantennas

    CERN Document Server

    Krasnok, Alexander E; Chigrin, Dmitry N; Kivshar, Yuri S; Belov, Pavel A


    We propose a novel approach to facilitate a readout processes of isolated negatively charged nitrogen-vacancy (NV) centers based on the concept of all-dielectric nanoantennas. We reveal that all-dielectric nanoantenna can significantly enhance both the emission rate and emission extraction efficiency of a photoluminescence signal from a single NV center in a diamond nanoparticle placed on a dielectric substrate. We prove that the proposed approach provides high directivity, large Purcell factor, and efficient beam steering, thus allowing an efficient far-field initialization and readout of several NV centers separated by subwavelength distances.

  16. Tactile display with dielectric multilayer elastomer actuatorsq (United States)

    Matysek, Marc; Lotz, Peter; Schlaak, Helmut F.


    Tactile perception is the human sensation of surface textures through the vibrations generated by stroking a finger over the surface. The skin responds to several distributed physical quantities. Perhaps the most important are high-frequency vibrations, pressure distributions (static shape) and thermal properties. The integration of tactile displays in man-machine interfaces promises a more intuitive handling. For this reason many tactile displays are developed using different technologies. We present several state-of-the-art tactile displays based on different types of dielectric elastomer actuators to clarify the advantages of our matrix display based on multilayer technology. Using this technology perpendicular and hexagonal arrays of actuator elements (tactile stimulators) can be integrated into a PDMS substrate. Element diameters down to 1 mm allow stimuli at the range of the human two-point-discrimination threshold. Driving the elements by column and row addressing enables various stimulation patterns with a reduced number of feeding lines. The transient analysis determines charging times of the capacitive actuators depending on actuator geometry and material parameters. This is very important to ensure an adequate dynamic characteristic of the actuators to stimulate the human skin by vibrations. The suitability of multilayer dielectric elastomer actuators for actuation in tactile displays has been determined. Beside the realization of a static tactile display - where multilayer DEA are integrated as drives for movable contact pins - we focus on the direct use of DEA as a vibrotactile display. Finally, we present the scenario and achieved results of a recognition threshold test. Even relative low voltages in the range of 800 V generate vibrations with 100% recognition ratio within the group of participants. Furthermore, the frequency dependent characteristic of the determined recognition threshold confirms with established literature.

  17. Dielectric optical invisibility cloaks (United States)

    Blair, J.; Tamma, V. A.; Park, W.; Summers, C. J.


    Recently, metamaterial cloaks for the microwave frequency range have been designed using transformative optics design techniques and experimentally demonstrated. The design of these structures requires extreme values of permittivity and permeability within the device, which has been accomplished by the use of resonating metal elements. However, these elements severely limit the operating frequency range of the cloak due to their non-ideal dispersion properties at optical frequencies. In this paper we present designs to implement a simpler demonstration of cloaking, the carpet cloak, in which a curved reflective surface is compressed into a flat reflective surface, effectively shielding objects behind the curve from view with respect to the incoming radiation source. This approach eliminates the need for metallic resonant elements. These structures can now be fabricated using only high index dielectric materials by the use of electron beam lithography and standard cleanroom technologies. The design method, simulation analysis, device fabrication, and near field optical microscopy (NSOM) characterization results are presented for devices designed to operate in the 1400-1600nm wavelength range. Improvements to device performance by the deposition/infiltration of linear, and potentially non-linear optical materials, were investigated.

  18. Equation of Energy Injection to a Dielectric Barrier Discharge Reactor (United States)

    Yao, Shuiliang; Weng, Shan; Jin, Qi; Han, Jingyi; Jiang, Boqiong; Wu, Zuliang


    The electric energy injection from a pulsed power supply to a planar type of dielectric barrier discharge (DBD) reactor at atmospheric pressure was studied. Relations of the energy injection with barrier materials, barrier thickness, peak voltage, gap distance, electrode area, and operation temperature were experimentally investigated. The energy injection is a function of relative permittivity, barrier thickness, peak voltage, gap distance, and electrode area. The influence of operation temperature on energy injection is slight in the range of 27-300 °C but becomes obvious in the range of 300-500 °C. A model was established using which the energy injection can be easily predicted. supported by National Natural Science Foundation of China (No. 11575159), Zhejiang Provincial Natural Science Foundation of China (No. LY13B070004), Program for Zhejiang Leading Team of S&T Innovation (No. 2013TD07), and National Natural Science Foundation of China (No. 51206146)

  19. High gradient insulator technology for the dielectric wall accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Sampayan, S.; Caporaso, G.; Carder, B. [and others


    Insulators composed of finely spaced alternating layers of dielectric and metal are thought to minimize secondary emission avalanche (SEA) growth. Most data to date was taken with small samples (order 10 cm{sup 2} area) in the absence of an ion or electron beam. The authors have begun long pulse (>1 {mu}s) high voltage testing of small hard seal samples. Further, they have performed short pulse (20 ns) high voltage testing of moderate scale bonded samples (order 100 cm{sup 2} area) in the presence of a 1 kA electron beam. Results thus far indicate a 1.0 to 4.0 increase in the breakdown electric field stress is possible with this technology.

  20. No-Voltage Meter (United States)


    VW- IKft, 1/4 H4 -Wv- IK!1, I/4W INTERNAL VOLTAGE NOTE ALL TRANSISTORS ARE 2N43A OR EQUIVALENT GERMANIUM ALLOY PNP AA ALKALINE BATTERY...D-,, regardless of polarity. This signal is then full-wave rectified by the diode-connected Germanium transistor bridge, T,, T-,, T3, and T4... Transistor T5 acts as a second current limiter. Resistor R2 was selected to give 90 f# of full-scale meter deflection with an input signal of 115 volts

  1. Ultrastable Natural Ester-Based Nanofluids for High Voltage Insulation Applications. (United States)

    Peppas, Georgios D; Bakandritsos, Aristides; Charalampakos, Vasilis P; Pyrgioti, Eleftheria C; Tucek, Jiri; Zboril, Radek; Gonos, Ioannis F


    Nanofluids for high voltage insulation systems have emerged as a potential substitute for liquid dielectrics in industrial applications. Nevertheless, the sedimentation of nanoparticles has been so far a serious barrier for their wide and effective exploitation. The present work reports on the development and in-depth characterization of colloidally ultrastable natural ester oil insulation systems containing iron oxide nanocrystals which lift the problem of sedimentation and phase separation. Compared to state-of-the-art systems, the final product is endowed with increased dielectric strength, faster thermal response, lower dielectric losses (decreased dissipation factor: tan δ), and very high endurance during discharge stressing. The developed nanofluid was studied and compared with a similar system containing commercial iron oxide nanoparticles, the latter demonstrating extensive sedimentation. Herein, the dielectric properties of the nanofluids are analyzed at various concentrations by means of breakdown voltage and dissipation factor measurements. The characterization techniques unequivocally demonstrate the high performance reliability of the reported nanofluid, which constitutes a significant breakthrough in the field of high voltage insulation technologies.

  2. Benchmarking of Voltage Sag Generators

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang


    The increased penetration of renewable energy systems, like photovoltaic and wind power systems, rises the concern about the power quality and stability of the utility grid. Some regulations for Low Voltage Ride-Through (LVRT) for medium voltage or high voltage applications, are coming into force...... to guide these grid-connected distributed power generation systems. In order to verify the response of such systems for voltage disturbance, mainly for evaluation of voltage sags/dips, a Voltage Sag Generator (VSG) is needed. This paper evaluates such sag test devices according to IEC 61000 in order...... to provide cheaper solutions to test against voltage sags. Simulation and experimental results demonstrate that the shunt impedance based VSG solution is the easiest and cheapest one for laboratory test applications. The back-to-back fully controlled converter based VSG is the most flexible solution...

  3. High voltage photoconductive switch package

    Energy Technology Data Exchange (ETDEWEB)

    Caporaso, George J.


    A photoconductive switch having a wide bandgap material substrate between opposing electrodes, and a doped dielectric filler that is in contact with both the electrodes and the substrate at the triple point. The dielectric filler material is doped with a conductive material to make it partially or completely conducting, to minimize the field enhancement near the triple point both when the substrate is not conducting in the "off" state and when the substrate is rendered conducting by radiation in the "on" state.

  4. Simulated and experimental studies on the array dielectric barrier discharge of water electrodes (United States)

    Wang, Lele; Huang, Xiutao; Chen, Junfeng; Wang, Shengming; Hu, Zhaoyang; Liu, Minghai


    A kind of dielectric barrier discharge (DBD) device composed of water electrodes with 3 × 3 forms can produce large-area low-temperature plasmas at atmospheric pressure. To reflect the discharge characteristics of DBD better, a dynamic simulation model, which is based on the voltage controlled current source (CCS), is established, then the established model in Matlab/Simulink is used to simulate the DBD in air. The voltage-current waves and Lissajous at a voltage of 10 kV, 11 kV and 12 kV peak value with a frequency of 15 kHz are studied. The change of the discharge power of DBD with a different amplitude and frequency of applied voltage is also analyzed. The result shows the voltage-current waves, Lissajous and discharge power of DBD under different conditions from the simulation agree well with those of the experiment. In addition, we propose a method to calculate the dielectric barrier capacitance {{C}}{{d}} and the gap capacitance {{C}}{{g}}, which is valid through analyzing the variation of capacitance at different voltage amplitudes.

  5. Role of secondary emission on discharge dynamics in an atmospheric pressure dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Tay, W. H.; Kausik, S. S.; Yap, S. L.; Wong, C. S., E-mail: [Plasma Technology Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)


    The discharge dynamics in an atmospheric pressure dielectric barrier discharge (DBD) is studied in a DBD reactor consisting of a pair of stainless steel parallel plate electrodes. The DBD discharge has been generated by a 50 Hz ac high voltage power source. The high-speed intensified charge coupled device camera is used to capture the images of filaments occurring in the discharge gap. It is observed that frequent synchronous breakdown of micro discharges occurs across the discharge gap in the case of negative current pulse. The experimental results reveal that secondary emissions from the dielectric surface play a key role in the synchronous breakdown of plasma filaments.

  6. ZrO2 as a high- dielectric for strained SiGe MOS devices

    Indian Academy of Sciences (India)

    R Mahapatra; G S Kar; C B Samantaray; A Dhar; D Bhattacharya; S K Ray


    The potential of ZrO2 thin film as a high- gate dielectric for scaled MOSFET devices has been studied. ZrO2 has been deposited directly on a Si0.8Ge0.2 substrate by reactive RF magnetron sputtering. An equivalent oxide thickness of < 20 Å with a leakage current of the order of 10–4 A/cm2 at 1 V has been obtained. Well-behaved capacitance–voltage characteristics with an interface state density of 2 × 1011 cm–2eV–1 have been achieved. The deposited dielectric exhibits low charge trapping under constant current stressing.

  7. Microwave tunable dielectric properties of multilayer CNT membranes for smart applications (United States)

    Liu, L.; Yang, Z. H.; Kong, L. B.; Yin, W. Y.; Wang, S.


    Multilayer multiwall carbon nanotube (MWCNT) silicone composite membranes with thickness greater than 10 μm were prepared with a spin-coating method. Dielectric permittivity and tunability of the circular membranes were measured from 0.1 to 7 GHz by using a single-port coaxial line method. The frequency and bias voltage dependent dielectric properties were interpreted based on percolation theory. The MWCNT membranes could be potentially used to develop smart components and structures working at radio wave or microwave frequencies.

  8. Phase resolved analysis of the homogeneity of a diffuse dielectric barrier discharge (United States)

    Baldus, Sabrina; Kogelheide, Friederike; Bibinov, Nikita; Stapelmann, Katharina; Awakowicz, Peter


    Cold atmospheric pressure plasmas have already proven their ability of supporting the healing process of chronic wounds. Especially simple configurations like a dielectric barrier discharge (DBD), comprising of one driven electrode which is coated with a dielectric layer, are of interest, because they are cost-effective and easy to handle. The homogeneity of such plasmas during treatment is necessary since the whole wound should be treated evenly. In this investigation phase resolved optical emission spectroscopy is used to investigate the homogeneity of a DBD. Electron densities and reduced electric field distributions are determined with temporal and spatial resolution and the differences for applied positive and negative voltage pulses are studied.

  9. Dielectric-breakdown and conduction-mechanism in a thinned alkali-free glass

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hoikwan; Lanagan, Michael T. [The Pennsylvania State University, University Park, PA (United States)


    The leakage current in alkali-free glass was analyzed to understand the dielectric breakdown behavior and the potential conduction mechanism. The dielectric breakdown strength and the leakage current were increased after the thickness of the glass had been recuded. To identify the predominant conduction mechanism, we carefully interpreted the dc voltage-current curves via fitting with various conduction mechanisms, e.g., Poole-Frenkel emission, Schottky emission, space charge-limited current, and hopping conduction. The result suggested that the space-charge-limited current and the hopping conduction of thermally-excited carriers were the most likely mechanisms of conduction in alkali-free glass.

  10. Nanostructure and nanochemistry of gate dielectrics and processing of tunable dielectrics by chemical vapor deposition (United States)

    Wang, Chang-Gong


    PbTiO3-SrTiO3 (PST) thin films that are voltage tunable were developed for high-frequency application by a metal-organic chemical vapor deposition technique at rates of 10--15 nm/min. PST films (90--150nm) were deposited on Pt/TiO2/SiO2/Si and Sapphire (0001) substrates and characterized by various techniques to control the composition and structure. The tunability and dielectric loss (tandelta) of a 90nm PST film were 37% and 0.02, respectively, at 1MHz and 3V in a parallel plates capacitor (Pt/PST/Pt) configuration. PST films on (0001) Sapphire were epitaxial with an orientation relationship of PST [1 1 1]// Sapphire [0 0 0 1], and in-plane alignment of PST [1 i 0]// Sapphire [2 i i 0] and PST [i i 2]// Sapphire [0 1 i 0]. A coplanar waveguide structure was used to determine the tunability (31.3%) and figure of merit (13 degrees/dB) of an epitaxial 100nm PST film on Sapphire at 12 GHz. The tandelta, derived from transmission-type resonator, is explained in terms of composition inhomogeneities and in-plane biaxial stress due to lattice mismatch between PST and Sapphire. A 4nm-ZrOx/1.2nm-SiOx layer structure was formed on 200mm Si wafers by a manufacturable atomic layer chemical vapor deposition (ALCVD) technique for advanced metal oxide semiconductor gate dielectrics. The nanostructure and nanochemistry of this gate stack were investigated by various techniques, before and after oxygen annealing (700°C). The results showed that a multiphase and heterogeneous structure evolved, defined as Zr-O/interlayer(IL)/Si stack. The critical parameters that control the nanostructural and nanochemical evolution are discussed using some simple mechanistic explanations and literature data. The stacks were characterized for their dielectric and electrical properties using a Pt/Zr-O/IL/Si capacitor configuration. The flat band shift (DeltaV FB), capacitance voltage hysteresis, and leakage current density were correlated with defects and roughness of the interface, thickness of IL

  11. Coordinated Voltage Control of Distributed PV Inverters for Voltage Regulation in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna


    This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... analysis, which is simple for computation and requires moderate automation and communication infrastructure. The proposed method is suitable for a hierarchical control structure where a supervisory controller has the provision to adapt the settings of local PV inverter controllers for overall system...

  12. Heat-pump performance: voltage dip/sag, under-voltage and over-voltage

    Directory of Open Access Journals (Sweden)

    William J.B. Heffernan


    Full Text Available Reverse cycle air-source heat-pumps are an increasingly significant load in New Zealand and in many other countries. This has raised concern over the impact wide-spread use of heat-pumps may have on the grid. The characteristics of the loads connected to the power system are changing because of heat-pumps. Their performance during under-voltage events such as voltage dips has the potential to compound the event and possibly cause voltage collapse. In this study, results from testing six heat-pumps are presented to assess their performance at various voltages and hence their impact on voltage stability.

  13. Estimation of Decreasing Losses of Active Power in Transformers in Setting Battery of Low-Voltage Capacitors


    V. N. Radkevich; M. N. Tarasova


    This paper describes an estimation method of decreasing losses of active power in power transformers with voltage 10(6)/0,4 kV after installation of devices of reactive power compensation on output side depending on voltage level, connected to capacity devices, taking into account dielectric loss in capacitors. Analysis of functional dependences was carried out. Investigation of function with a help of derivations was carried out. Points of function extremum and also its intervals of rise and...

  14. Tailoring the Dielectric Layer Structure for Enhanced Performance of Organic Field-Effect Transistors: The Use of a Sandwiched Polar Dielectric Layer

    Directory of Open Access Journals (Sweden)

    Shijiao Han


    Full Text Available To investigate the origins of hydroxyl groups in a polymeric dielectric and its applications in organic field-effect transistors (OFETs, a polar polymer layer was inserted between two polymethyl methacrylate (PMMA dielectric layers, and its effect on the performance as an organic field-effect transistor (OFET was studied. The OFETs with a sandwiched dielectric layer of poly(vinyl alcohol (PVA or poly(4-vinylphenol (PVP containing hydroxyl groups had shown enhanced characteristics compared to those with only PMMA layers. The field-effect mobility had been raised more than 10 times in n-type devices (three times in the p-type one, and the threshold voltage had been lowered almost eight times in p-type devices (two times in the n-type. The on-off ratio of two kinds of devices had been enhanced by almost two orders of magnitude. This was attributed to the orientation of hydroxyl groups from disordered to perpendicular to the substrate under gate-applied voltage bias, and additional charges would be induced by this polarization at the interface between the semiconductor and dielectrics, contributing to the accumulation of charge transfer.

  15. Voltage Swells Improvement in Low Voltage Network Using Dynamic Voltage Restorer

    Directory of Open Access Journals (Sweden)

    R. Omar


    Full Text Available Problem statement: Voltage disturbances are the most common power quality problem due to the increased use of a large numbers of sophisticated electronic equipment in industrial distribution system. The voltage disturbances such as voltage sags, swells, harmonics, unbalance and flickers. High quality in the power supply is needed, since failures due to such disturbances usually have a high impact on production cost. There are many different solutions to compensate voltage disturbances but the use of a DVR is considered to be the most cost effective method. The objective of this study is to propose a new topology of a DVR in order to mitigate voltage swells using a powerful power custom device namely the Dynamic Voltage Restorer (DVR. Approach: New configuration of a DVR with an improvement of a controller based on direct-quadrature-zero method has been introduced to compensate voltage swells in the network. Results: The effectiveness of the DVR with its controller were verify using Matlab/Simulinks SimPower Toolbox and then implemented using 5KVA DVR experimental setup. Simulations and experimental results demonstrate the effective dynamic performance of the proposed configuration. Conclusion: The implimentation of the proposed DVR validate the capabilities in mitigating of voltage swells effectiveness.During voltage swells, the DVR injects an appropriate voltage to maintain the load voltage at its nominal value.

  16. Isomerically Pure Tetramethylrhodamine Voltage Reporters. (United States)

    Deal, Parker E; Kulkarni, Rishikesh U; Al-Abdullatif, Sarah H; Miller, Evan W


    We present the design, synthesis, and application of a new family of fluorescent voltage indicators based on isomerically pure tetramethylrhodamines. These new Rhodamine Voltage Reporters, or RhoVRs, use photoinduced electron transfer (PeT) as a trigger for voltage sensing, display excitation and emission profiles in the green to orange region of the visible spectrum, demonstrate high sensitivity to membrane potential changes (up to 47% ΔF/F per 100 mV), and employ a tertiary amide derived from sarcosine, which aids in membrane localization and simultaneously simplifies the synthetic route to the voltage sensors. The most sensitive of the RhoVR dyes, RhoVR 1, features a methoxy-substituted diethylaniline donor and phenylenevinylene molecular wire at the 5'-position of the rhodamine aryl ring, exhibits the highest voltage sensitivity to date for red-shifted PeT-based voltage sensors, and is compatible with simultaneous imaging alongside green fluorescent protein-based indicators. The discoveries that sarcosine-based tertiary amides in the context of molecular-wire voltage indicators prevent dye internalization and 5'-substituted voltage indicators exhibit improved voltage sensitivity should be broadly applicable to other types of PeT-based voltage-sensitive fluorophores.

  17. Experimental study on surface modification of PET films under bipolar nanosecond-pulse dielectric barrier discharge in atmospheric air

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yunfei [State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049 (China); Su, Chunqiang [Xi’an High Voltage Apparatus Research Institute, Xi’an 710077 (China); Ren, Xiang; Fan, Chuan; Zhou, Wenwu [State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Feng [School of Electrical and Information Engineering, Hunan University, Changsha 410082 (China); Ding, Weidong, E-mail: [State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049 (China)


    Highlights: • Homogeneous DBD is generated under bipolar nanosecond pulse in atmospheric air. • Effects of surface modification under homogeneous DBD are discussed. • Dielectric properties of the PET films are fully studied from relative dielectric constant ε{sub r}, dielectric loss tangent tan δ and breakdown voltages V{sub b}. • Oxygen-containing polar groups are considered to be the most essential reason for dielectric property changes. - Abstract: Dielectric barrier discharge (DBD) is widely used for surface modification of polymer films. In this paper, DBD characteristics under bipolar repetitive frequency nanosecond pulse in atmospheric air are studied and surface properties of polyethylene terephthalate films under homogeneous DBD and filamentary DBD modification are compared through scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and dielectric test equipment. It is found that the discharge is homogeneous when gap spacing d is less than 1.2 mm and filamentary when d is within the range of 3.0 mm to 5.8 mm. SEM pictures reveal that films under homogeneous DBD present a smooth surface while intensive “gully-like” etches appear on the surface of the films under filamentary DBD, which can result in local insulation defects and is disadvantageous to surface modification. It is found from the XPS analysis that a number of oxygen-containing polar groups are introduced onto the surface of the film modified by homogeneous DBD compared with the untreated one. Experimental results for dielectric properties indicate that the three parameters: relative dielectric constant ε{sub r}, dielectric loss tangent tan δ and breakdown voltages V{sub b} are all changed in different degree after surface modification. And possible reason for the phenomenon is discussed.

  18. Method of stress and measurement modes for research of thin dielectric films of MIS structures (United States)

    Andreev, Vladimir V.; Maslovsky, Vladimir M.; Andreev, Dmitrii V.; Stolyarov, Alexander A.


    The paper proposes a new method of stress and measurement modes for research of thin dielectric films of MIS structures. The method realizes injection of the most part of charge into gate dielectric in one of stress modes: either current owing through dielectric is constant or voltage applied to gate is constant. In order to acquire an additional information about changing of charge state of MIS structure, the stress condition is interrupted in certain time ranges and during these time ranges the mode, in which structure is, is the mode of measurement. In measurement mode, changing of electric fields at interfaces between dielectric and semiconductor is monitored. By using these data, density of charge, which is accumulated in gate dielectric, and its centroid are calculated. Besides, by using these data, one studies processes of generation and relaxation of charge in dielectric. In order to raise precision of the method and reduce an influence of switching effects in measurement mode, density of measurement current should be much lower than density of stress current.

  19. A new analytical model of high voltage silicon on insulator (SOI) thin film devices

    Institute of Scientific and Technical Information of China (English)

    Hu Sheng-Dong; Zhang Bo; Li Zhao-Ji


    A new analytical model of high voltage silicon on insulator (SOI) thin film devices is proposed, and a formula of silicon critical electric field is derived as a function of silicon film thickness by solving a 2D Poisson equation from an effective ionization rate, with a threshold energy taken into account for electron multiplying. Unlike a conventional silicon critical electric field that is constant and independent of silicon film thickness, the proposed silicon critical electric field increases sharply with silicon film thickness decreasing especially in the case of thin films, and can come to 141 V/μm at a film thickness of 0.1 μm which is much larger than the normal value of about 30 V/μm. From the proposed formula of silicon critical electric field, the expressions of dielectric layer electric field and vertical breakdown voltage (VB,V) are obtained. Based on the model, an ultra thin film can be used to enhance dielectric layer electric field and so increase vertical breakdown voltage for SOI devices because of its high silicon critical electric field, and with a dielectric layer thickness of 2 μm the vertical breakdown voltages reach 852 and 300V for the silicon film thicknesses of 0.1 and 5μm, respectively. In addition, a relation between dielectric layer thickness and silicon film thickness is obtained, indicating a minimum vertical breakdown voltage that should be avoided when an SOI device is designed. 2D simulated results and some experimental results are in good agreement with analytical results.

  20. Finite element modelling of dielectric elastomer minimum energy structures (United States)

    O'Brien, Benjamin; McKay, Thomas; Calius, Emilio; Xie, Shane; Anderson, Iain


    This paper presents an experimentally validated finite element model suitable for simulating the quasi-static behaviour of Dielectric Elastomer Minimum Energy Structure(s) (DEMES). A DEMES consists of a pre-stretched Dielectric Elastomer Actuator (DEA) adhered to a thin, flexible frame. The tension in the stretched membrane causes the frame to curl up, and when a voltage is applied, the frame returns to its initial planar state thus forming a useful bending actuator. The simulation method presented here incorporates a novel strain energy function suitable for simulating general DEA actuator elements. When compared against blocked force data from our previous work, the new model provides a good fit with an order of magnitude reduction in computational time. Furthermore, the model accurately matched experimental data on the free displacement of DEMES formed with non-equibiaxially pre-stretched VHB4905 membranes driven by 2500 V. Non-equibiaxially pre-stretching the membranes allowed control of effective frame stiffness and bending moment, this was exploited by using the model to optimise stroke at 2500 V in a hypothetical case study. Dielectric constant measurements for non-equibiaxially stretched VHB4905 are also presented.

  1. Solution-processable organic dielectrics for graphene electronics (United States)

    Mattevi, Cecilia; Colléaux, Florian; Kim, HoKwon; Lin, Yen-Hung; Park, Kyung T.; Chhowalla, Manish; Anthopoulos, Thomas D.


    We report the fabrication, at low-temperature, of solution processed graphene transistors based on carefully engineered graphene/organic dielectric interfaces. Graphene transistors based on these interfaces show improved performance and reliability when compared with traditional SiO2 based devices. The dielectric materials investigated include Hyflon AD (Solvay), a low-k fluoropolymer, and various organic self-assembled monolayer (SAM) nanodielectrics. Both types of dielectric are solution processed and yield graphene transistors with similar operating characteristics, namely high charge carrier mobility, hysteresis free operation, negligible doping effect and improved operating stability as compared to bare SiO2 based devices. Importantly, the use of SAM nanodielectrics enables the demonstration of low operating voltage ( < |1.5| V), solution-processable and flexible graphene transistors with tunable doping characteristics through molecular engineering of the SAM’s molecular length and terminal group. The work is a significant step towards graphene microelectronics where large-volume and low-temperature processing are required.

  2. Pulsed electrical breakdown of a void-filled dielectric (United States)

    Anderson, R. A.; Lagasse, R. R.; Schroeder, J. L.


    We report breakdown strengths in a void-filled dielectric material, epoxy containing 48 vol % hollow glass microballoon filler, which is stressed with unipolar voltage pulses of the order of 10 μs duration. The microballoon voids had mean diameters of approximately 40 μm and contained SO2 gas at roughly 30% atmospheric pressure. This void-filled material displays good dielectric strength (of the order of 100 kV mm-1) under these short-pulse test conditions. Results from a variety of electrode geometries are reported, including arrangements in which the electric stress is highly nonuniform. Conventional breakdown criteria based on mean or peak electric stress do not account for these data. A statistics-based predictive breakdown model is developed, in which the dielectric is divided into independent, microballoon-sized "discharge cells" and the spontaneous discharge of a single cell is presumed to launch full breakdown of the composite. We obtain two empirical parameters, the mean and standard deviation of the spontaneous discharge field, by fitting breakdown data from two electrode geometries having roughly uniform fields but with greatly differing volumes of electrically stressed material. This model accounts for many aspects of our data, including the inherent statistical scatter and the dependence on the stressed volume, and it provides informative predictions with electrode geometries giving highly nonuniform fields. Issues related to computational spatial resolution and cutoff distance are also discussed.

  3. Dielectric relaxations investigation of a synthesized epoxy resin polymer (United States)

    Jilani, Wissal; Mzabi, Nissaf; Gallot-Lavallée, Olivier; Fourati, Najla; Zerrouki, Chouki; Zerrouki, Rachida; Guermazi, Hajer


    A diglycidylether of bisphenol A (DGEBA) epoxy resin was synthesized, and cured with 3,3'-diaminodiphenyl sulfone (DDS) at a curing temperature of 120 °C. The relaxation properties of the realized polymers were studied by two complementary techniques: dielectric relaxation spectroscopy (DRS), in the temperature range 173-393K and in the frequency interval 10-1-106 Hz, and thermally stimulated depolarization current (TSDC) with a windowing polarization process. Current-voltage (I-V) measurements were also carried out to study interfacial relaxations. Dielectric data were analyzed in terms of permittivity and electric modulus variations. Three relaxation processes ( γ, β and α) have been identified. They were found to be frequency and temperature dependent and were interpreted in terms of the Havriliak-Negami approach. Relaxation parameters were determined by fitting the experimental data. The temperature dependence of the relaxation time was well fitted by the Arrhenius law for secondary relaxations, while the Vogel-Fulcher-Tamann model was found to better fit the τ( T) variations for α relaxation. We found τ 0 = 4.9 10-12 s, 9.6 10-13 s and 1.98 10-7 s for γ, β and α relaxations, respectively. The obtained results were found to be consistent with those reported in the literature. Due to the calculation of the low-frequency data of dielectric loss by the Hamon approximation, the Maxwell-Wagner-Sillars (MWS) relaxation was highlighted.

  4. Dielectric breakdown during Cs+ sputtering of polyvinyl chloride (United States)

    Wahoud, F.; Guillot, J.; Audinot, J. N.; Bertrand, P.; Delcorte, A.; Migeon, H. N.


    Thin films of insulating polymers are sometimes analyzed by secondary ion mass spectrometry (SIMS) or by X-ray photoelectron spectroscopy (XPS) without the use of an electron gun. In this work, both SIMS and XPS have been used to study the chemical and structural modifications due to the charge effect during Cs+ sputtering of a thin film of polyvinyl chloride (PVC). The kinetic energy distribution study shows that at a small primary fluence ˜1015 Cs+ ions/cm2, the dielectric breakdown voltage of the PVC film is reached, i.e. the minimum voltage that causes a portion of an insulator to become electrically conductive. XPS study indicates that the conducting phase created in the PVC film after energetic Cs+ bombardment consists of graphitized carbon and metallic cesium clusters. After the dielectric breakdown of the film, the positive charge, previously accumulated on the surface, is neutralized through the conductive regions, which are created in the insulating film. During Cs+ sputtering of a PVC film, the chemical structure of the analyzed surface is completely modified and some ionic bonds such as CsC and CsCl are also created.

  5. Electrohydrodynamic force in dielectric barrier discharge plasma actuators

    Energy Technology Data Exchange (ETDEWEB)

    Boeuf, J P; Lagmich, Y; Unfer, Th; Callegari, Th; Pitchford, L C [CPAT-CNRS, Universite Paul Sabatier, 118 Route de Narbonne, Toulouse 31062 (France)


    Surface dielectric barrier discharges (DBDs) have been proposed as actuators for flow control. In this paper we discuss the basic mechanisms responsible for the electrohydrodynamic (EHD) force exerted by the discharge on the gas molecules. A two-dimensional fluid model of the DBD is used to describe the plasma dynamics, to understand the basic physics associated with the EHD force and to give some quantitative estimation of the force under simplified conditions. The results show that for ramp or sinusoidal voltage waveforms, the discharge consists of large amplitude short current pulses during which a filamentary plasma spreads along the surface, separated in time by long duration, low current discharge phases of a Townsend or corona type. The contribution of the low current phases to the total force exerted by the discharge on the gas is dominant because their duration is much longer than that of the current pulses and because the force takes place in a much larger volume. A description of the different discharge regimes and a parametric study of the EHD force as a function of voltage rise time and dielectric thickness is presented.

  6. Analysis Code for High Gradient Dielectric Insulator Surface Breakdown

    Energy Technology Data Exchange (ETDEWEB)

    Ives, Robert Lawrence [Calabazas Creek Research, Inc.; Verboncoeur, John [University of California - Berkeley; Aldan, Manuel [University of California, Berkeley


    High voltage (HV) insulators are critical components in high-energy, accelerator and pulsed power systems that drive diverse applications in the national security, nuclear weapons science, defense and industrial arenas. In these systems, the insulator may separate vacuum/non-vacuum regions or conductors with high electrical field gradients. These insulators will often fail at electric fields over an order of magnitude lower than their intrinsic dielectric strength due to flashover at the dielectric interface. Decades of studies have produced a wealth of information on fundamental processes and mechanisms important for flashover initiation, but only for relatively simple insulator configurations in controlled environments. Accelerator and pulsed power system designers are faced with applying the fundamental knowledge to complex, operational devices with escalating HV requirements. Designers are forced to rely on “best practices” and expensive prototype testing, providing boundaries for successful operation. However, the safety margin is difficult to estimate, and system design must be very conservative for situations where testing is not practicable, or replacement of failed parts is disruptive or expensive. The Phase I program demonstrated the feasibility of developing an advanced code for modeling insulator breakdown. Such a code would be of great interest for a number of applications, including high energy physics, microwave source development, fusion sciences, and other research and industrial applications using high voltage devices.

  7. A novel duct silencer using dielectric elastomer absorbers (United States)

    Lu, Zhenbo; Cui, Yongdong; Zhu, Jian; Debiasi, Marco


    A novel duct silencer was developed using dielectric elastomer absorbers (DEAs). Dielectric elastomer, a lightweight, high elastic energy density and large deformation under high DC/AC voltages smart material, was used to fabricate this new generation actuator. The acoustic performances of this duct silencer were experimentally investigated in a transmission loss (TL) measurement system using two-load method. It was found that the resonance peaks of this new duct silencer could be controlled by applying various DC voltages, a maximum resonance shift of 59.5Hz for the resonance peaks was achieved which indicated that this duct silencer could be adjusted to absorb broadband range noise without any addition mechanical part. Furthermore, the resonance shift and multiple resonances mechanisms using DEAs were proposed and discussed in the present paper which was aiming to achieve broadband noise reduction. The present results also provide insight into the appropriateness of the absorber for possible use as new acoustic treatment to replace the traditional acoustic treatment.

  8. Materials Fundamentals of Gate Dielectrics

    CERN Document Server

    Demkov, Alexander A


    This book presents materials fundamentals of novel gate dielectrics that are being introduced into semiconductor manufacturing to ensure the continuous scalling of the CMOS devices. This is a very fast evolving field of research so we choose to focus on the basic understanding of the structure, thermodunamics, and electronic properties of these materials that determine their performance in device applications. Most of these materials are transition metal oxides. Ironically, the d-orbitals responsible for the high dielectric constant cause sever integration difficulties thus intrinsically limiting high-k dielectrics. Though new in the electronics industry many of these materials are wel known in the field of ceramics, and we describe this unique connection. The complexity of the structure-property relations in TM oxides makes the use of the state of the art first-principles calculations necessary. Several chapters give a detailed description of the modern theory of polarization, and heterojunction band discont...

  9. Leaky Modes of Dielectric Cavities

    CERN Document Server

    Mansuripur, Masud; Jakobsen, Per


    In the absence of external excitation, light trapped within a dielectric medium generally decays by leaking out (and also by getting absorbed within the medium). We analyze the leaky modes of a parallel-plate slab, a solid glass sphere, and a solid glass cylinder, by examining those solutions of Maxwell's equations (for dispersive as well as non-dispersive media) which admit of a complex-valued oscillation frequency. Under certain circumstances, these leaky modes constitute a complete set into which an arbitrary distribution of the electromagnetic field residing inside a dielectric body can be expanded. We provide completeness proofs, and also present results of numerical calculations that illustrate the relationship between the leaky modes and the resonances of dielectric cavities formed by a simple parallel-plate slab, a glass sphere, and a glass cylinder.

  10. Dielectric Bow-tie Nanocavity

    CERN Document Server

    Lu, Qijing; Zou, Chang-Ling


    We propose a novel dielectric bow-tie nanocavity consisting of two tip-to-tip opposite triangle semiconductor nanowires, whose end faces are coated by silver nanofilms. Based on the advantages of the dielectric slot and tip structures, and the high reflectivity from the silver mirror, light can be confined in this nanocavity with low loss. We demonstrate that the mode excited in this nanocavity has a deep subwavelength mode volume of 2.8*10^-4 um3 and a high quality factor of 4.9*10^4 (401.3), consequently an ultrahigh Purcell factor of 1.6*10^7 (1.36*10^5), at 4.5 K (300 K) around the resonance wavelength of 1550 nm. This dielectric bow-tie nanocavity may find applications for integrated nanophotonic circuits, such as high-efficiency single photon source, thresholdless nanolaser, and cavity QED strong coupling experiments.

  11. Voltage-controlled domain wall traps in ferromagnetic nanowires (United States)

    Bauer, Uwe; Emori, Satoru; Beach, Geoffrey S. D.


    Electrical control of magnetism has the potential to bring about revolutionary new spintronic devices, many of which rely on efficient manipulation of magnetic domain walls in ferromagnetic nanowires. Recently, it has been shown that voltage-induced charge accumulation at a metal-oxide interface can influence domain wall motion in ultrathin metallic ferromagnets, but the effects have been relatively modest and limited to the slow, thermally activated regime. Here we show that a voltage can generate non-volatile switching of magnetic properties at the nanoscale by modulating interfacial chemistry rather than charge density. Using a solid-state ionic conductor as a gate dielectric, we generate unprecedentedly strong voltage-controlled domain wall traps that function as non-volatile, electrically programmable and switchable pinning sites. Pinning strengths of at least 650 Oe can be readily achieved, enough to bring to a standstill domain walls travelling at speeds of at least ~20 m s-1. We exploit this new magneto-ionic effect to demonstrate a prototype non-volatile memory device in which voltage-controlled domain wall traps facilitate electrical bit selection in a magnetic nanowire register.

  12. Ultra-compact Marx-type high-voltage generator (United States)

    Goerz, David A.; Wilson, Michael J.


    An ultra-compact Marx-type high-voltage generator includes individual high-performance components that are closely coupled and integrated into an extremely compact assembly. In one embodiment, a repetitively-switched, ultra-compact Marx generator includes low-profile, annular-shaped, high-voltage, ceramic capacitors with contoured edges and coplanar extended electrodes used for primary energy storage; low-profile, low-inductance, high-voltage, pressurized gas switches with compact gas envelopes suitably designed to be integrated with the annular capacitors; feed-forward, high-voltage, ceramic capacitors attached across successive switch-capacitor-switch stages to couple the necessary energy forward to sufficiently overvoltage the spark gap of the next in-line switch; optimally shaped electrodes and insulator surfaces to reduce electric field stresses in the weakest regions where dissimilar materials meet, and to spread the fields more evenly throughout the dielectric materials, allowing them to operate closer to their intrinsic breakdown levels; and uses manufacturing and assembly methods to integrate the capacitors and switches into stages that can be arranged into a low-profile Marx generator.

  13. Capacitive Cells for Dielectric Constant Measurement (United States)

    Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco


    A simple capacitive cell for dielectric constant measurement in liquids is presented. As an illustrative application, the cell is used for measuring the degradation of overheated edible oil through the evaluation of their dielectric constant.

  14. Capacitive Cells for Dielectric Constant Measurement (United States)

    Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco


    A simple capacitive cell for dielectric constant measurement in liquids is presented. As an illustrative application, the cell is used for measuring the degradation of overheated edible oil through the evaluation of their dielectric constant.

  15. Voltage Dependence of Supercapacitor Capacitance

    Directory of Open Access Journals (Sweden)

    Szewczyk Arkadiusz


    Full Text Available Electronic Double-Layer Capacitors (EDLC, called Supercapacitors (SC, are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We propose an experimental method, based on monitoring of charging and discharging a supercapacitor, which enables to evaluate the charge in an SC structure as well as the Capacitance-Voltage (C-V dependence. The measurement setup, method and experimental results of charging/discharging commercially available supercapacitors in various voltage and current conditions are presented. The total charge stored in an SC structure is proportional to the square of voltage at SC electrodes while the charge on electrodes increases linearly with the voltage on SC electrodes. The Helmholtz capacitance increases linearly with the voltage bias while a sublinear increase of total capacitance was found. The voltage on SC increases after the discharge of electrodes due to diffusion of charges from the electrolyte to the electrodes. We have found that the recovery voltage value is linearly proportional to the initial bias voltage value.

  16. Influence of porosity on electrical properties of low-k dielectrics irradiated with vacuum-ultraviolet radiation (United States)

    Choudhury, F. A.; Nguyen, H. M.; Baklanov, M. R.; de Marneffe, J. F.; Li, W.; Pei, D.; Benjamin, D. I.; Zheng, H.; King, S. W.; Lin, Y.-H.; Fung, H.-S.; Chen, C.-C.; Nishi, Y.; Shohet, J. L.


    During plasma processing, low-k dielectrics are exposed to high levels of vacuum ultraviolet (VUV) radiation emitted from the plasma. The porous structure of these materials makes them more sensitive to modification because of their low density and consequently deep penetration of active species into the film. Here, we investigate the changes to electrical properties of porous low-k dielectrics as a function of porosity after VUV irradiation. Organosilicate low-k films of porosities between 30% and 50% were exposed to synchrotron VUV radiation at 8 eV with a fluence of approximately 5 × 1014 photons/cm2. Capacitance-voltage measurements showed an increase in the dielectric constant along with a flat-band voltage shift. FTIR results show methyl depletion as well as water uptake after VUV treatment. These show that deterioration of the electrical properties after VUV exposure and the degree of damage are found to be higher for the more porous films.

  17. Routes to increase the conversion and the energy efficiency in the splitting of CO2 by a dielectric barrier discharge (United States)

    Ozkan, A.; Bogaerts, A.; Reniers, F.


    Here, we present routes to increase CO2 conversion into CO using an atmospheric pressure dielectric-barrier discharge. The change in conversion as a function of simple plasma parameters, such as power, flow rate, but also frequency, on-and-off power pulse, thickness and the chemical nature of the dielectric, wall and gas temperature, are described. By means of an in-depth electrical characterization of the discharge (effective plasma voltage, dielectric voltage, plasma current, number and lifetime of the microdischarges), combined with infrared analysis of the walls of the reactor, optical emission spectroscopy for the gas temperature, and mass spectrometry for the CO2 conversion, we propose a global interpretation of the effect of all the experimental parameters on the conversion and efficiency of the reaction.

  18. Performance of soft dielectric laminated composites (United States)

    Gei, Massimiliano; Springhetti, Roberta; Bortot, Eliana


    This paper contains a thorough investigation of the performance of electrically activated layered soft dielectric composite actuators under plane deformation. Noting that the activation can be induced by controlling either the voltage or the surface charge, the overall behaviour of the system is obtained via homogenization at large strains, taking either the macroscopic electric field or the macroscopic electric displacement field as independent electrical variables. The performance of a two-phase composite actuator compared to that of the homogeneous case is highlighted for few boundary-value problems and for different values of stiffness and permittivity ratios between constituents being significant for applications, where the soft matrix is reinforced by a relatively small volume fraction of a stiff and high-permittivity phase. For charge-controlled devices, it is shown that some composite layouts admit, on one hand, the occurrence of pull-in/snap-through instabilities that can be exploited to design release-actuated systems, and on the other hand, the possibility of thickening at increasing surface charge density.

  19. Extinction by the long dielectric needles

    CERN Document Server

    Cherkas, Nadejda L


    Electromagnetic wave extinction by the very long but finite dielectric needle is compared with that by the infinite dielectric cylinder for an oblique incidence of the electromagnetic wave. It is shown that the renormalized Hankel functions without the logarithmic terms should be used for the calculation of the extinction per unit length of the infinite dielectric cylinder to apply it for extinction calculations by the finite dielectric cylinder.

  20. Dielectric nanostructures with high laser damage threshold (United States)

    Ngo, C. Y.; Hong, L. Y.; Deng, J.; Khoo, E. H.; Liu, Z.; Wu, R. F.; Teng, J. H.


    Dielectric-based metamaterials are proposed to be the ideal candidates for low-loss, high-efficiency devices. However, to employ dielectric nanostructures for high-power applications, the dielectric material must have a high laser-induced damaged threshold (LIDT) value. In this work, we investigated the LIDT values of dielectric nanostructures for high-power fiber laser applications. Consequently, we found that the fabricated SiO2 nanostructured lens can withstand laser fluence exceeding 100 J/cm2.

  1. Dielectric barrier discharges applied for optical spectrometry (United States)

    Brandt, S.; Schütz, A.; Klute, F. D.; Kratzer, J.; Franzke, J.


    The present review reflects the importance of dielectric barrier discharges for optical spectrometric detection in analytical chemistry. In contrast to usual discharges with a direct current the electrodes are separated by at least one dielectric barrier. There are two main features of the dielectric barrier discharges: they can serve as dissociation and excitation devices as well as ionization sources, respectively. This article portrays various application fields of dielectric barrier discharges in analytical chemistry used for elemental and molecular detection with optical spectrometry.

  2. Self-Healable Electrical Insulation for High Voltage Applications (United States)

    Williams, Tiffany S.


    Polymeric aircraft electrical insulation normally degrades by partial discharge with increasing voltage, which causes excessive localized Joule heating in the material and ultimately leads to dielectric failure of the insulator through thermal breakdown. Developing self-healing insulation could be a viable option to mitigate permanent mechanical degradation, thus increasing the longevity of the insulation. Instead of relying on catalyst and monomer-filled microcapsules to crack, flow, and cure at the damaged sites described in well-published mechanisms, establishment of ionic crosslinks could allow for multiple healing events to occur with the added benefit of achieving full recovery strength under certain thermal environments. This could be possible if the operating temperature of the insulator is the same as or close to the temperature where ionic crosslinks are formed. Surlyn, a commercial material with ionic crosslinks, was investigated as a candidate self-healing insulator based off prior demonstrations of self-healing behavior. Thin films of varying thicknesses were investigated and the effects of thickness on the dielectric strength were evaluated and compared to representative polymer insulators. The effects of thermal conditioning on the recovery strength and healing were observed as a function of time following dielectric breakdown. Moisture absorption was also studied to determine if moisture absorption rates in Surlyn were lower than that of common polyimides.

  3. Dielectric material degradation monitoring of dielectric barrier discharge plasma actuators (United States)

    Hanson, Ronald E.; Houser, Nicole M.; Lavoie, Philippe


    It is a known phenomenon that some dielectric materials used to construct plasma actuators degrade during operation. However, the rate at which this process occurs, to what extent, as well as a method to monitor is yet to be established. In this experimental study, it is shown that electrical measurements can be used to monitor changes in the material of the plasma actuators. The procedure we introduce for monitoring the actuators follows from the work of Kriegseis, Grundmann, and Tropea [Kriegseis et al., J. Appl. Phys. 110, 013305 (2011)], who used Lissajous figures to measure actuator power consumption and capacitance. In the present study, we quantify changes in both the power consumption and capacitance of the actuators over long operating durations. It is shown that the increase in the effective capacitance of the actuator is related to degradation (thinning) of the dielectric layer, which is accompanied by an increase in actuator power consumption. For actuators constructed from layers of Kapton® polyimide tape, these changes are self-limiting. Although the polyimide film degrades relatively quickly, the underlying adhesive layer appears to remain intact. Over time, the effective capacitance was found to increase by up to 36%, 25%, and 11% for actuators constructed with 2, 3, and 4 layers of Kapton tape, respectively. A method is presented to prevent erosion of the Kapton dielectric layer using a coating of Polydimethylsiloxane oil. It is shown the application of this treatment can delay the onset of degradation of the Kapton dielectric material.

  4. Understanding and Improving High Voltage Vacuum Insulators for Microsecond Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Javedani, J B; Goerz, D A; Houck, T L; Lauer, E J; Speer, R D; Tully, L K; Vogtlin, G E; White, A D


    High voltage insulation is one of the main areas of pulsed power research and development, and dielectric breakdown is usually the limiting factor in attaining the highest possible performance in pulsed power devices. For many applications the delivery of pulsed power into a vacuum region is the most critical aspect of operation. The surface of an insulator exposed to vacuum can fail electrically at an applied field more than an order or magnitude below the bulk dielectric strength of the insulator. This mode of breakdown, called surface flashover, imposes serious limitations on the power flow into a vacuum region. This is especially troublesome for applications where high voltage conditioning of the insulator and electrodes is not practical and for applications where relatively long pulses, on the order of several microseconds, are required. The goal of this project is to establish a sound fundamental understanding of the mechanisms that lead to surface flashover, and then evaluate the most promising techniques to improve vacuum insulators and enable high voltage operation at stress levels near the intrinsic bulk breakdown limits of the material. The approach we proposed and followed was to develop this understanding through a combination of theoretical and computation methods coupled with experiments to validate and quantify expected behaviors. In this report we summarize our modeling and simulation efforts, theoretical studies, and experimental investigations. The computational work began by exploring the limits of commercially available codes and demonstrating methods to examine field enhancements and defect mechanisms at microscopic levels. Plasma simulations with particle codes used in conjunction with circuit models of the experimental apparatus enabled comparisons with experimental measurements. The large scale plasma (LSP) particle-in-cell (PIC) code was run on multiprocessor platforms and used to simulate expanding plasma conditions in vacuum gap regions

  5. The inactivation of Chlorella spp. with dielectric barrier discharge in gas-liquid mixture (United States)

    Song, Dan; Sun, Bing; Zhu, Xiaomei; Yan, Zhiyu; Liu, Hui; Liu, Yongjun


    The inactivation of Chlorella spp. with high voltage and frequency pulsed dielectric barrier discharge in hybrid gas-liquid reactor with a suspension electrode was studied experimentally. In the hybrid gas-liquid reactor, a steel plate was used as high voltage electrode while a quartz plate as a dielectric layer, another steel plate placing in the aqueous solution worked as a whole ground electrode. A suspension electrode is installed near the surface of solution between high voltage and ground electrode to make the dielectric barrier discharge uniform and stable, the discharge gap was between the quartz plate and the surface of the water. The effect of peak voltage, treatment time, the initial concentration of Chlorella spp. and conductivity of solution on the inactivation rate of Chlorella spp. was investigated, and the inactivation mechanism of Chlorella spp. preliminarily was studied. Utilizing this system inactivation of Chlorella spp., the inactivation rate increased with increasing of peak voltage, treatment time and electric conductivity. It was found that the inactivation rate of Chlorella spp. arrived at 100% when the initial concentration was 4 × 106 cells mL-1, and the optimum operation condition required a peak voltage of 20 kV, a treatment time of 10 min and a frequency of 7 kHz. Though the increasing of initial concentration of the Chlorella spp. contributed to the addition of interaction probability between the Chlorella spp. and O3, H2O2, high-energy electrons, UV radiation and other active substances, the total inactivation number raise, but the inactivation rate of the Chlorella spp. decreased.

  6. Disinfection of fresh chicken breast fillets with in-package atmospheric cold plasma: effect of treatment voltage and time (United States)

    Effects of treatment voltage and time of in-package atmospheric cold plasma (ACP) were studied on ozone formation, microbiological quality, surface color, and pH of fresh chicken fillets. Samples were sealed in food trays in air, treated with a dielectric-barrier-discharge (DBD) ACP system, and stor...

  7. A compact, all solid-state LC high voltage generator. (United States)

    Fan, Xuliang; Liu, Jinliang


    LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 μH, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications.

  8. Influential Mechanism of the HPEF Parameters on the Dielectric Properties of Fresh Vegetables

    Directory of Open Access Journals (Sweden)

    Liu Yong-qiu


    Full Text Available The pretreatment of fresh vegetables with HPEF can improve lyophilized speed and reduce energy consumption, but when people study how to use fresh vegetables dielectric properties online to monitor the change of lyophilized water, they need to consider the impact of parameters of high voltage pulsed electric field on dielectric properties of fresh vegetables. Therefore, according to the author's many years of study and practical experience, this study first analyzes the dielectric properties of fresh vegetables and then develops the required equivalent circuit of this study; finally, it focuses on the impact of the mechanism of pulsed electric field parameters. The result of this study will provide a useful reference to the treatment of fresh vegetables with the HPEF.

  9. A dielectric logging tool with insulated collar for formation fluid detection around borehole (United States)

    Wang, Bin; Li, Kang; Kong, Fan-Min; Zhao, Jia


    A dielectric tool with insulated collar for analyzing fluid saturation outside a borehole was introduced. The UWB (ultra-wideband) antenna mounted on the tool was optimized to launch a transient pulse. The broadband evaluation method provided more advantages when compared with traditional dielectric tools. The EM (electromagnetic) power distribution outside the borehole was studied, and it was shown that energy was propagated in two modes. Furthermore, the mechanism of the modes was discussed. In order to increase this tools' investigation depth, a novel insulated collar was introduced. In addition, operation in difference formations was discussed and this tool proved to be able to efficiently launch lateral EM waves. Response voltages indicated that the proposed scheme was able to evaluate the fluid saturation of reservoir formations and dielectric dispersion properties. It may be used as an alternative tool for imaging logging applications.

  10. Experimental Verification for Improving Dielectric Strength of Polymers by Using Clay Nanoparticles

    Directory of Open Access Journals (Sweden)

    Ahmed Thabet Mohamed


    Full Text Available Nanoparticles are a considerable attention due to very interesting properties have been accepted to base matrix materials during the nanostructure incorporation. Therefore, this paper has been presented an experimental study for the dielectric strength of several new industrial polymer nanocomposites specimens. It~has been studied the effects of clay nanoparticles incorporation into polypropylene (PP, polyvinyl chloride (PVC, low density polyethylene (LDPE, and~high density polyethylene (HDPE on electric properties, dielectric properties, dielectric strength and voltage endurance significantly for variant polymers by a simplified breakdown model. Experimental results have been compared with respect to unfilled industrial materials under AC electric field (uniform and non-uniform and variant thermal temperatures.

  11. Electro-elastic modeling of a dielectric elastomer diaphragm for a prosthetic blood pump (United States)

    Goulbourne, Nakhiah C.; Frecker, Mary I.; Mockensturm, Eric


    A dielectric elastomer diaphragm is to be designed for potential use in a prosthetic blood pump. Application of an electric field deforms the membrane such that it moves from an initially flat configuration to an inflated state. This motion creates positive displacement of blood from the cardiac chambers thus mimicking the pump-like behavior of the natural heart. A comprehensive large deformation model accounting for the combined dielectric and elastic effect has been formulated. This paper presents recent developments in the model to further incorporate the entire nonlinear range of material elastic behavior and to more accurately represent the applied electric field by keeping the voltage constant as the membrane thickness decreases. The updated model is used to calculate the effects of varying system parameters such as pressure, voltage, prestretch, material constants, and membrane geometry. Analytical results are obtained for biaxially stretched 3M VHB 4905 polyacrylate films.

  12. Improvement of Dielectric Barrier Discharge Plasma Reactor for Ozone Generation by Electrode Shape (United States)

    Shimizu, Masaki; Sato, Tohru; Kato, Shoji; Mukaigawa, Seiji; Takaki, Koichi; Fujiwara, Tamiya

    An effect of electrode shape on ozone generation in dielectric barrier discharge reactor is described in this article. Three different shape electrodes were employed as ground electrodes. A plane electrode is 6 cm in width, and 20 cm in length. A trench electrode has large number of knife-edge rails. A multipoint electrode has large number of four-sided pyramid projections on the plane. A high voltage plane electrode is covered with 0.5 mm thickness alumina layer worked as dielectric barrier. The experimental results show that the breakdown for the multipoint electrode occurs at 7.0 kVpp. This value is lower than 8.4 kVpp that is the breakdown voltage of the plane electrode. The ozone yield increases from 80 g/kWh to 130 g/kWh by changing the electrode shape from the plane to the multipoint. The ozone generation efficiency decreased with increase of the ozone concentration.

  13. Characterization of vertical strain silicon MOSFET incorporating dielectric pocket (SDP-VMOSFET)

    Energy Technology Data Exchange (ETDEWEB)

    Napiah, Z. A. F. M., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:; Makhtar, N., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:; Othman, M. A., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:; Idris, M. I., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:; Arith, F., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:; Yasin, N. Y. M., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:; Taib, S. N., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Centre for Telecommunication Research and Innovation (CeTRI), Faculty of Electronic and Computer Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia)


    The vertical Metal-Oxide-Semiconductor Field-Effect-Transistor (MOSFET) leads to a double channel width that can increase the packaging density. The strained silicon MOSFET was introduced to modify the carrier transport properties of silicon in order to enhance transport of both electrons and holes within strained layer. Dielectric pocket was act to control encroachment of the drain doping into the channel and reduce short channel effects (SCE). SDP-VMOSFET which was a combination of those advantages was proposed to overcome the SCE in term of leakage current, threshold voltage roll-off also Drain Induce Barrier Lowering (DIBL). As a result, SDP-VMOSFET produces a better threshold voltage and DIBL compared to related structures. Meanwhile, it gives slightly increased for leakage current compared to Vertical MOSFET Incorporating Dielectric Pocket. The characteristics of the SDP-VMOSFET are analyzed in order to optimize the performance of the device and leading to the next generation of IC technology.

  14. Insulation Resistance and Leakage Currents in Low-Voltage Ceramic Capacitors with Cracks (United States)

    Teverovsky, Alexander A.


    Measurement of insulation resistance (IR) in multilayer ceramic capacitors (MLCCs) is considered a screening technique that ensures the dielectric is defect-free. This work analyzes the effectiveness of this technique for revealing cracks in ceramic capacitors. It is shown that absorption currents prevail over the intrinsic leakage currents during standard IR measurements at room temperature. Absorption currents, and consequently IR, have a weak temperature dependence, increase linearly with voltage (before saturation), and are not sensitive to the presence of mechanical defects. In contrary, intrinsic leakage currents increase super-linearly with voltage and exponentially with temperature (activation energy is in the range from 0.6 eV to 1.1 eV). Leakage currents associated with the presence of cracks have a weaker dependence on temperature and voltage compared to the intrinsic leakage currents. For this reason, intrinsic leakage currents prevail at high temperatures and voltages, thus masking the presence of defects.

  15. Characterization of high voltage components using partial discharges; Caracterisation de composants haute tension par decharges partielles

    Energy Technology Data Exchange (ETDEWEB)

    Boucheteau, R.; Biero, H.; Prisset, C. [CEA Le Ripault, 37 - Tours (France)


    Because of the increasing size reduction of high voltage components, the classical dielectric control means do not allow to predict neither the in-service breakdown probability, nor the service life of the components even when submitted to a voltage greater to the nominal value of use. Therefore a new approach is developed which is based on the measurement of partial discharges (PD) occurring with respect to the voltage applied. PDs are due to impurities inside the materials. Pertinent parameters, such as the PDs occurrence voltage, the mean discharge current and the maximum charge of PDs are defined in order to determine a correlation between the PDs measurement and the state of the insulating material. The influence of aging is not well known. Thus the materials are submitted to more or less severe environments in order to determine the significant evolutions of PDs. (J.S.) 2 refs.

  16. Design and Development of Autonomous High Voltage Driving System for DEAP Actuator in Radiator Thermostat

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.


    make a high voltage capacitive load driving system to be necessary. The only energy source battery determines it needs to be an autonomous system. The detailed system specifications have been introduced and the corresponding system level design has been proposed. In addition, the detailed design......In radiator thermostat applications, DEAP (Dielectric Electro Active Polymer) actuator tends to be a good candidate to replace the conventional self-actuating or step motor based actuator due to its intrinsic advantages. The capacitive property and high voltage (HV) driving demand of DEAP actuator...... and implementation information has been provided as well, including the power and control stage inside the high voltage converter, the output voltage measurement circuit, the feedback control, etc. Finally, the experimental results have been provided to validate the capability and performance of the driving system....

  17. Experimental study on temperature characteristics and energy conversion in packed bed reactor with dielectric barrier discharge (United States)

    Li, Sen; Tang, Zuchen; Gu, Fan


    The temperature characteristics and energy conversion in packed bed reactor combined with a dielectric barrier discharge (DBD) plasma was investigated experimentally. The pellet temperatures of two types packed bed reactor, cylindrical reactor and parallel-plate reactor, was measured in conditions of various inlet voltage of DBD plasma. The relationship between pellet temperature of the packed bed and applied voltage of DBD plasma was discovered. The experimental result indicates a tendency that the pellet temperature of packed bed increases as the applied voltage of inlet plasma increases. When the voltage of inlet plasma is high enough, the pellet temperature increment decreases. Simultaneously,the packed bed temperature is sensitive to the inlet plasma energy and there is a potential application to heat exchanger. Moreover the proportion of energy consumption of plasma inputting into packed bed reactor was analyzed and calculated. The mechanisms that electrical energy of inlet plasma is transformed into heat energy in the two phases, gaseous and pellets of the packed bed reactor are different. The energy consumption in pellet phase is dielectric polarization loss and depends on packed bed geometry and DBD plasma etc. The energy consumption in gaseous phase is plasma sheath procedure. The important factors effecting on gas discharge are gaseous component and voltage, frequency of power.

  18. Optical Emission Spectroscopy Investigation of a Surface Dielectric Barrier Discharge Plasma Aerodynamic Actuator

    Institute of Scientific and Technical Information of China (English)

    LI Ying-Hong; WU Yun; JIA Min; ZHOU Zhang-Wen; GUO Zhi-Gang; PU Yi-Kang


    The optical emission spectroscopy of a surface dielectric barrier discharge plasma aerodynamic actuator is investigated with different electrode configurations, applied voltages and driving frequencies. The rotational temperature of N2 (C3IIu) molecule is calculated according to its rotational emission band near 380.5 nm. The average electron energy of the discharge is evaluated by emission intensity ratio of first negative system to second positive system of N2. The rotational temperature is sensitive to the inner space of an electrode pair. The average electron energy shows insensitivity to the applied voltage, the driving frequency and the electrode configuration.

  19. Organic thin film transistors with polymer brush gate dielectrics synthesized by atom transfer radical polymerization

    DEFF Research Database (Denmark)

    Pinto, J.C.; Whiting, G.L.; Khodabakhsh, S.


    , synthesized by atom transfer radical polymerization (ATRP), were used to fabricate low voltage OFETs with both evaporated pentacene and solution deposited poly(3-hexylthiophene). The semiconductor-dielectric interfaces in these systems were studied with a variety of methods including scanning force microscopy......Low operating voltage is an important requirement that must be met for industrial adoption of organic field-effect transistors (OFETs). We report here solution fabricated polymer brush gate insulators with good uniformity, low surface roughness and high capacitance. These ultra thin polymer films...

  20. Hybrid gate dielectric materials for unconventional electronic circuitry. (United States)

    Ha, Young-Geun; Everaerts, Ken; Hersam, Mark C; Marks, Tobin J


    Recent advances in semiconductor performance made possible by organic π-electron molecules, carbon-based nanomaterials, and metal oxides have been a central scientific and technological research focus over the past decade in the quest for flexible and transparent electronic products. However, advances in semiconductor materials require corresponding advances in compatible gate dielectric materials, which must exhibit excellent electrical properties such as large capacitance, high breakdown strength, low leakage current density, and mechanical flexibility on arbitrary substrates. Historically, conventional silicon dioxide (SiO2) has dominated electronics as the preferred gate dielectric material in complementary metal oxide semiconductor (CMOS) integrated transistor circuitry. However, it does not satisfy many of the performance requirements for the aforementioned semiconductors due to its relatively low dielectric constant and intransigent processability. High-k inorganics such as hafnium dioxide (HfO2) or zirconium dioxide (ZrO2) offer some increases in performance, but scientists have great difficulty depositing these materials as smooth films at temperatures compatible with flexible plastic substrates. While various organic polymers are accessible via chemical synthesis and readily form films from solution, they typically exhibit low capacitances, and the corresponding transistors operate at unacceptably high voltages. More recently, researchers have combined the favorable properties of high-k metal oxides and π-electron organics to form processable, structurally well-defined, and robust self-assembled multilayer nanodielectrics, which enable high-performance transistors with a wide variety of unconventional semiconductors. In this Account, we review recent advances in organic-inorganic hybrid gate dielectrics, fabricated by multilayer self-assembly, and their remarkable synergy with unconventional semiconductors. We first discuss the principals and functional