WorldWideScience

Sample records for voltage recording technique

  1. Transient Voltage Recorder

    Science.gov (United States)

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

    2002-01-01

    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. High voltage test techniques

    CERN Document Server

    Kind, Dieter

    2001-01-01

    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

  3. Modern recording techniques

    CERN Document Server

    Huber, David Miles

    2013-01-01

    As the most popular and authoritative guide to recording Modern Recording Techniques provides everything you need to master the tools and day to day practice of music recording and production. From room acoustics and running a session to mic placement and designing a studio Modern Recording Techniques will give you a really good grounding in the theory and industry practice. Expanded to include the latest digital audio technology the 7th edition now includes sections on podcasting, new surround sound formats and HD and audio.If you are just starting out or looking for a step up

  4. Offset Correction Techniques for Voltage Sense Amplifiers

    NARCIS (Netherlands)

    Groeneveld, S.

    2006-01-01

    This report deals with offset correction techniques for voltage sense amplifiers and is divided into two different parts: 1) mismatch and 2) offset correction techniques. First a literature study is done on the subject mismatch with specially focus on the future. Mismatch of a transistor is determin

  5. High-voltage test and measuring techniques

    CERN Document Server

    Hauschild, Wolfgang

    2014-01-01

    It is the intent of this book to combine high-voltage (HV) engineering with HV testing technique and HV measuring technique. Based on long-term experience gained by the authors as lecturer and researcher as well as member in international organizations, such as IEC and CIGRE, the book will reflect the state of the art as well as the future trends in testing and diagnostics of HV equipment to ensure a reliable generation, transmission and distribution of electrical energy. The book is intended not only for experts but also for students in electrical engineering and high-voltage engineering.

  6. High-voltage test and measuring techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hauschild, Wolfgang; Lemke, Eberhard

    2014-04-01

    Reflects the unit of both HV testing and measuring technique. Intended as an ''application guide'' for the relevant IEC standards. Refers also to future trends in HV testing and measuring technique. With numerous illustrations. It is the intent of this book to combine high-voltage (HV) engineering with HV testing technique and HV measuring technique. Based on long-term experience gained by the authors as lecturer and researcher as well as member in international organizations, such as IEC and CIGRE, the book will reflect the state of the art as well as the future trends in testing and diagnostics of HV equipment to ensure a reliable generation, transmission and distribution of electrical energy. The book is intended not only for experts but also for students in electrical engineering and high-voltage engineering.

  7. Soft computing techniques in voltage security analysis

    CERN Document Server

    Chakraborty, Kabir

    2015-01-01

    This book focuses on soft computing techniques for enhancing voltage security in electrical power networks. Artificial neural networks (ANNs) have been chosen as a soft computing tool, since such networks are eminently suitable for the study of voltage security. The different architectures of the ANNs used in this book are selected on the basis of intelligent criteria rather than by a “brute force” method of trial and error. The fundamental aim of this book is to present a comprehensive treatise on power system security and the simulation of power system security. The core concepts are substantiated by suitable illustrations and computer methods. The book describes analytical aspects of operation and characteristics of power systems from the viewpoint of voltage security. The text is self-contained and thorough. It is intended for senior undergraduate students and postgraduate students in electrical engineering. Practicing engineers, Electrical Control Center (ECC) operators and researchers will also...

  8. Digitally Recorded Impulse Voltage Waveform and its Parameters

    Science.gov (United States)

    Sato, Shuji; Ichikawa, Hironori; Saitou, Tatsunori; Harada, Tatsuya; Hanai, Masahiro

    Whereas high resolution digital recorders are used in recording the impulse voltage tests in prominent accreditation laboratories worldwide, a usage of an 8 bit recorder is also allowed by IEC publication. An 8 bit recorder is, due to its nature, known to record a waveform with 0.4% vertical resolution and it has not been appreciated for determining a peak value of lightning impulse in the reference measuring system where the scale factor is often evaluated with 0.1% or less uncertainty. This paper demonstrates simulation in which an 8 bit record with an internal noise is fed into the lightning impulse parameter determination software and the computed parameters were compared with theoretical values. The results show that, if suitable software is used, errors in parameters deduced from an 8 bit record is as small as those derived from a 12 bit record, suggesting an inexpensive 8 bit recorder can replace a 12 bit in impulse voltage measurements.

  9. COHERENT-LIGHT RECORDING TECHNIQUES.

    Science.gov (United States)

    The purpose of this report is to summarize, define and demonstrate techniques necessary for the application of coherent light to the problems of...Investigations into such areas as the coherent light source itself, modulation, deflection or scanning techniques, readout techniques and the evaluation of recording media are reported.

  10. Imperfect space clamp permits electrotonic interactions between inhibitory and excitatory synaptic conductances, distorting voltage clamp recordings.

    Directory of Open Access Journals (Sweden)

    Alon Poleg-Polsky

    Full Text Available The voltage clamp technique is frequently used to examine the strength and composition of synaptic input to neurons. Even accounting for imperfect voltage control of the entire cell membrane ("space clamp", it is often assumed that currents measured at the soma are a proportional indicator of the postsynaptic conductance. Here, using NEURON simulation software to model somatic recordings from morphologically realistic neurons, we show that excitatory conductances recorded in voltage clamp mode are distorted significantly by neighboring inhibitory conductances, even when the postsynaptic membrane potential starts at the reversal potential of the inhibitory conductance. Analogous effects are observed when inhibitory postsynaptic currents are recorded at the reversal potential of the excitatory conductance. Escape potentials in poorly clamped dendrites reduce the amplitude of excitatory or inhibitory postsynaptic currents recorded at the reversal potential of the other conductance. In addition, unclamped postsynaptic inhibitory conductances linearize the recorded current-voltage relationship of excitatory inputs comprising AMPAR and NMDAR-mediated components, leading to significant underestimation of the relative contribution by NMDARs, which are particularly sensitive to small perturbations in membrane potential. Voltage clamp accuracy varies substantially between neurons and dendritic arbors of different morphology; as expected, more reliable recordings are obtained from dendrites near the soma, but up to 80% of the synaptic signal on thin, distant dendrites may be lost when postsynaptic interactions are present. These limitations of the voltage clamp technique may explain how postsynaptic effects on synaptic transmission could, in some cases, be attributed incorrectly to presynaptic mechanisms.

  11. New Control Technique Applied in Dynamic Voltage Restorer for Voltage Sag Mitigation

    Directory of Open Access Journals (Sweden)

    Rosli Omar

    2010-01-01

    Full Text Available The Dynamic Voltage Restorer (DVR was a power electronics device that was able to compensate voltage sags on critical loads dynamically. The DVR consists of VSC, injection transformers, passive filters and energy storage (lead acid battery. By injecting an appropriate voltage, the DVR restores a voltage waveform and ensures constant load voltage. There were so many types of the control techniques being used in DVR for mitigating voltage sags. The efficiency of the DVR depends on the efficiency of the control technique involved in switching the inverter. Problem statement: Simulation and experimental investigation toward new algorithms development based on SVPWM. Understanding the nature of DVR and performance comparisons between the various controller technologies available. The proposed controller using space vector modulation techniques obtain higher amplitude modulation indexes if compared with conventional SPWM techniques. Moreover, space vector modulation techniques can be easily implemented using digital processors. Space vector PWM can produce about 15% higher output voltage than standard Sinusoidal PWM. Approach: The purpose of this research was to study the implementation of SVPWM in DVR. The proposed control algorithm was investigated through computer simulation by using PSCAD/EMTDC software. Results: From simulation and experimental results showed the effectiveness and efficiency of the proposed controller based on SVPWM in mitigating voltage sags in low voltage distribution systems. It was concluded that its controller also works well both in balance and unbalance conditions of voltages. Conclusion/Recommendations: The simulation and experimental results of a DVR using PSCAD/EMTDC software based on SVPWM technique showed clearly the performance of the DVR in mitigating voltage sags. The DVR operates without any difficulties to inject the appropriate voltage component to correct rapidly any anomaly in the supply voltage to keep the

  12. Zero-voltage switching technique in dc/dc converters

    Science.gov (United States)

    Liu, Kwang-Hwa; Lee, Fred C. Y.

    1990-07-01

    A novel resonant switch operating under the principle of zero-voltage switching is presented. In contrast to the zero-current switching, this technique eliminates the switching loss and dv/dt noise due to the discharging of MOSFET junction capacitances and the reverse recovery of diodes, and enables the converters to operate at high frequencies. A dc analysis of the converter is carried out. The duality relationship between the zero-current switching technique and the zero-voltage switching technique is derived. The two techniques are compared using an example showing the duality between a current-mode quasi-resonant Buck converter and a voltage-mode quasi-resonant boost converter. A 5-MHz 50 V to 5 V flyback converter employing the zero-voltage switching technique has been implemented. The circuit contains the smallest number of components possible, and yet maintains high efficiency at high switching frequency.

  13. Medium voltage switching techniques; Techniques de coupure en moyenne tension

    Energy Technology Data Exchange (ETDEWEB)

    Theoleyre, S. [Schneider Electric S.A., 92 - Boulogne-Billancourt (France)

    1999-08-01

    The link between power production plants and users is ensured by a grid or an arborescence of connections, lines and cables. For exploitation, maintenance or safety reasons it may be necessary to switch off and switch on the current at any point of the network. Switching devices are used for this purpose and the choice of a given device depends on the nature of the current (load, overload and fault currents) and of the domain of application. During switching and during continuous operation, these devices are submitted to dielectric, thermal, electrodynamical and mechanical stresses. The most important stresses are those linked with transient phenomena and involving an electric arc. This paper deals principally with the switching of medium voltage (1 to 52 kV) AC currents using circuit breakers. The first part analyzes the phenomena that occur during the operation of circuit breakers while the second part presents the four switching techniques currently used: in air, oil, vacuum and in sulfur hexafluoride (SF{sub 6}). (J.S.) 35 refs.

  14. 30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage power centers and transformers... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination... record shall be kept in a book approved by the Secretary. High-Voltage Longwalls Source: 67 FR 11001,...

  15. Optimization Techniques To Record Deduplication

    Directory of Open Access Journals (Sweden)

    Rangarajan Rangaswamy

    2012-01-01

    Full Text Available Duplicate record detection is important for data preprocessing and cleaning. Artificial Bee Colony (ABC is one of the most recently introduced algorithms based on the intelligent foraging behavior of a honey bee swarm. Our approach to duplicate detection is the use of ABC algorithm for generating the optimal similarity measure to decide whether the data is duplicate or not. In the training phase, ABC algorithm is used to generate the optimal similarity measure. Once the optimal similarity measure obtained, the deduplication of remaining datasets is done with the help of optimal similarity measure generated from the ABC algorithm. We have used Restaurant and Cora datasets to analyze the proposed algorithm and the performance of the proposed algorithm is compared against the genetic programming technique with the help of evaluation metrics.

  16. 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

    2009-01-01

    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.

  17. Design techniques for low-voltage analog integrated circuits

    Science.gov (United States)

    Rakús, Matej; Stopjaková, Viera; Arbet, Daniel

    2017-08-01

    In this paper, a review and analysis of different design techniques for (ultra) low-voltage integrated circuits (IC) are performed. This analysis shows that the most suitable design methods for low-voltage analog IC design in a standard CMOS process include techniques using bulk-driven MOS transistors, dynamic threshold MOS transistors and MOS transistors operating in weak or moderate inversion regions. The main advantage of such techniques is that there is no need for any modification of standard CMOS structure or process. Basic circuit building blocks like differential amplifiers or current mirrors designed using these approaches are able to operate with the power supply voltage of 600 mV (or even lower), which is the key feature towards integrated systems for modern portable applications.

  18. Inverter-based circuit design techniques for low supply voltages

    CERN Document Server

    Palani, Rakesh Kumar

    2017-01-01

    This book describes intuitive analog design approaches using digital inverters, providing filter architectures and circuit techniques enabling high performance analog circuit design. The authors provide process, supply voltage and temperature (PVT) variation-tolerant design techniques for inverter based circuits. They also discuss various analog design techniques for lower technology nodes and lower power supply, which can be used for designing high performance systems-on-chip.    .

  19. A technique to reduce plasma armature formation voltage

    Energy Technology Data Exchange (ETDEWEB)

    Jamison, K.A. (Science Applications International Corp., Shalimar, FL (US)); Littrell, D.M. (Air Force Armament Lab., Eglin AFB, FL (United States))

    1991-01-01

    The initiation of a plasma armature by foil vaporization in a railgun is often accompanied by a large, fast, voltage transient appearing on both the breech and muzzle of the gun. For a railgun driven by an inductor/opening switch power supply, this voltage transient becomes a concern during current commutation from the switch to the railgun. To lessen the requirements on the opening switch, techniques must be found to reduce the armature formation voltage. This paper presents the experimental results from railgun firings at AFATL's Electromagnetic Launcher Basic Research Facility (Site A-15, Eglin Air Force Base, Florida) using different shapes of initiation foils. These foils have been designed to vaporize into a plasma armature with reduced transient voltages. A design criteria was developed to ensure that all portions of the foil vaporize at slightly different times.

  20. COHERENT LIGHT-RECORDING TECHNIQUES.

    Science.gov (United States)

    On the basis of diffraction theory, quantum-mechanics and information theory, it is shown that the principle of coherent light recording is the...mechanical, magnetic or electric approaches. Photographic coherent light recording tests were made by the dynamic sweep tests on 16 mm Recordak Micro-File

  1. Dynamic Voltage Restorer Based on Space Vector Pulse Width Modulation Technique

    Directory of Open Access Journals (Sweden)

    B.N S P Venkatesh

    2011-07-01

    Full Text Available Power Quality problems encompass a wide range of disturbances such as voltage sags, swells, flicker,harmonics distortion and interruptions. The strategic deployment of custom power devices has been proposed asone of the means to protect sensitive loads from power quality problems such as voltage sags and swells. The Dynamic Voltage Restorer (DVR is a power electronic device that is used to inject 3-phase voltage in series and in synchronism with the distribution feeder voltages in order to compensate voltage sag and similarly itreacts quickly to inject the appropriate voltage component (negative voltage magnitude in order to compensate voltage swell. The principal component of the DVR is a voltage source inverter that generates three phase voltages and provides the voltage support to a sensitive load during voltage sags and swells. Pulse Width Modulation Technique is very critical for proper control of DVR. Sinusoidal Pulse Width Modulation (SPWM and Space Vector Pulse Width Modulation (SVPWM control techniques are used for controlling the DVR. Inthis work, the operation of DVR is presented and the control technique used for voltage source inverter is Space Vector PWM technique. Space vector PWM can utilize the better dc voltage and generates the fewer harmonic in inverter output voltage than Sinusoidal PWM technique. This work describes the DVR based on Space Vector PWM which provides voltage support to sensitive loads and is simulated by using MATLAB/SIMULINK. Simulation results show that the control approach is able to compensate for any type of voltage sags and swells.

  2. Pollution Maintenance Techniques in Coastal High Voltage Installations

    Directory of Open Access Journals (Sweden)

    E. Pyrgioti

    2011-02-01

    Full Text Available Pollution of outdoor high voltage insulators is a common problem for utilities, with a considerable impact to power system reliability. In an effort to prevent possible flashovers due to pollution, many methods have been applied, aiming to improve the insulation performance, either by suppressing the formation of surface conductivity or by increasing the possible insulation level. In the case of substations, the selection of the appropriate technique is complex due to certain issues correlated to the nature of the installation. In this paper, several techniques usually implemented by utilities, are investigated based on the experienced gained in the case of Crete, a Greek island in southern Europe, where due to the coastal development of the power system, the majority of high voltage installations are exposed to intense marine pollution. The technique of coating insulators with Room Temperature Vulcanized Silicone Rubber (RTV SIR has proved rather efficient and therefore is presented extendedly. Correlation of the material behaviour with environmental conditions is discussed and results from long term monitoring, including environmental parameters and leakage current measurements, in a 150 kV Substation are presented. It is shown that RTV SIR coatings have remarkably suppressed surface activity and that porcelain insulators exhibit different activity period when coated.

  3. Negative voltage bandgap reference with multilevel curvature compensation technique

    Science.gov (United States)

    Xi, Liu; Qian, Liu; Xiaoshi, Jin; Yongrui, Zhao; Lee, Jong-Ho

    2016-05-01

    A novel high-order curvature compensation negative voltage bandgap reference (NBGR) based on a novel multilevel compensation technique is introduced. Employing an exponential curvature compensation (ECC) term with many high order terms in itself, in a lower temperature range (TR) and a multilevel curvature compensation (MLCC) term in a higher TR, a flattened and better effect of curvature compensation over the TR of 165 °C (-40 to 125 °C) is realised. The MLCC circuit adds two convex curves by using two sub-threshold operated NMOS. The proposed NBGR implemented in the Central Semiconductor Manufacturing Corporation (CSMC) 0.5 μm BCD technology demonstrates an accurate voltage of -1.183 V with a temperature coefficient (TC) as low as 2.45 ppm/°C over the TR of 165 °C at a -5.0 V power supply; the line regulation is 3 mV/V from a -5 to -2 V supply voltage. The active area of the presented NBGR is 370 × 180 μm2. Project supported by the Fund of Liaoning Province Education Department (No. L2013045).

  4. Security Techniques for the Electronic Health Records.

    Science.gov (United States)

    Kruse, Clemens Scott; Smith, Brenna; Vanderlinden, Hannah; Nealand, Alexandra

    2017-08-01

    The privacy of patients and the security of their information is the most imperative barrier to entry when considering the adoption of electronic health records in the healthcare industry. Considering current legal regulations, this review seeks to analyze and discuss prominent security techniques for healthcare organizations seeking to adopt a secure electronic health records system. Additionally, the researchers sought to establish a foundation for further research for security in the healthcare industry. The researchers utilized the Texas State University Library to gain access to three online databases: PubMed (MEDLINE), CINAHL, and ProQuest Nursing and Allied Health Source. These sources were used to conduct searches on literature concerning security of electronic health records containing several inclusion and exclusion criteria. Researchers collected and analyzed 25 journals and reviews discussing security of electronic health records, 20 of which mentioned specific security methods and techniques. The most frequently mentioned security measures and techniques are categorized into three themes: administrative, physical, and technical safeguards. The sensitive nature of the information contained within electronic health records has prompted the need for advanced security techniques that are able to put these worries at ease. It is imperative for security techniques to cover the vast threats that are present across the three pillars of healthcare.

  5. Process, Voltage and Temperature Compensation Technique for Cascode Modulated PAs

    DEFF Research Database (Denmark)

    Sira, Daniel; Larsen, Torben

    2013-01-01

    transconductance amplifier. The predistorted varying envelope signal is applied to the cascode gate of the PA. It is shown that the proposed PVT compensation technique significantly reduces the PVT spread of the PA linearity indicators and improves the PA linearity. Simulations were performed in a 0.13 μm CMOS......This paper presents a process, voltage and temperature (PVT) compensation method for a cascode modulated polar power amplifier (PA). It is shown that it is possible to create a baseband replica circuit of the PA that has the same AM-AM nonlinearity as the PA itself. The replica circuit......, that represents a transistor level model (empirical model) of the cascode modulated PA, is utilized in a PA analog predistorter. The analog predistorter linearizes and compensates for PVT variation of the cascode modulated PA. The empirical model is placed in the negative feedback of an operational...

  6. A robust and fast generic voltage sag detection technique

    DEFF Research Database (Denmark)

    L. Dantas, Joacillo; Lima, Francisco Kleber A.; Branco, Carlos Gustavo C.;

    2015-01-01

    In this paper, a fast and robust voltage sag detection algorithm, named VPS2D, is introduced. Using the DSOGI, the algorithm creates a virtual positive sequence voltage and monitories the fundamental voltage component of each phase. After calculating the aggregate value in the o:;3-reference frame......, the algorithm can rapidly identify the starting and the ending of symmetric and asymmetric voltage sags, even if there are harmonics on the grid. Simulation and experimental results are given to validate the proposed algorithm....

  7. A Survey on Voltage Boosting Techniques for Step-Up DC-DC Converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam Prasad; Gorji, Saman Asghari;

    2016-01-01

    , researches on new voltage boosting techniques are inevitable for various power converter applications. This can be achieved either by additional magnetic or by electric field storage elements with switching elements (switch and/or diode) in different configurations. Such combination of primary voltage...... boosting techniques and topologies are large, which at times may be confusing and difficult to follow/adapt for different applications. Considering these aspects and in order to make a clear sketch of the general law and framework of various voltage boosting techniques, this paper comprehensively reviews...... different voltage boosting techniques and categorizes them according to their circuit performance....

  8. SVPWM Technique with Varying DC-Link Voltage for Common Mode Voltage Reduction in a Matrix Converter and Analytical Estimation of its Output Voltage Distortion

    Science.gov (United States)

    Padhee, Varsha

    Common Mode Voltage (CMV) in any power converter has been the major contributor to premature motor failures, bearing deterioration, shaft voltage build up and electromagnetic interference. Intelligent control methods like Space Vector Pulse Width Modulation (SVPWM) techniques provide immense potential and flexibility to reduce CMV, thereby targeting all the afore mentioned problems. Other solutions like passive filters, shielded cables and EMI filters add to the volume and cost metrics of the entire system. Smart SVPWM techniques therefore, come with a very important advantage of being an economical solution. This thesis discusses a modified space vector technique applied to an Indirect Matrix Converter (IMC) which results in the reduction of common mode voltages and other advanced features. The conventional indirect space vector pulse-width modulation (SVPWM) method of controlling matrix converters involves the usage of two adjacent active vectors and one zero vector for both rectifying and inverting stages of the converter. By suitable selection of space vectors, the rectifying stage of the matrix converter can generate different levels of virtual DC-link voltage. This capability can be exploited for operation of the converter in different ranges of modulation indices for varying machine speeds. This results in lower common mode voltage and improves the harmonic spectrum of the output voltage, without increasing the number of switching transitions as compared to conventional modulation. To summarize it can be said that the responsibility of formulating output voltages with a particular magnitude and frequency has been transferred solely to the rectifying stage of the IMC. Estimation of degree of distortion in the three phase output voltage is another facet discussed in this thesis. An understanding of the SVPWM technique and the switching sequence of the space vectors in detail gives the potential to estimate the RMS value of the switched output voltage of any

  9. A Review on Power System Voltage Stability and Optimization Techniques

    Directory of Open Access Journals (Sweden)

    T. Madhuranthaka

    2016-11-01

    Full Text Available Power system voltage stability is a one of the major focused areas in recent days due to mismatch between generation and demand. Maintenance of voltage stability is a challenging issue in planning and security assessment of power systems. Voltage stability is the ability of a power system to maintain steady acceptable voltages at all buses in the power system under normal operating conditions and after being subjected to a disturbance. Long-term voltage instability problems can occur in heavily loaded systems where the electrical distance is large between the generator and the load. Timely application of reactive power compensation or load shedding may prevent this type of voltage instability. System reactive power handling capacity can be improved with Flexible AC Transmission System (FACTS devices. Identification of critical system locations to undertake appropriate remedial measures in operation is the concern. This paper reviews the performance of various types FACTS controllers in power system voltage stability problem and focuses on different optimization methods implemented for optimal placement and sizing of FACTS devices to minimize power losses.

  10. Analog IC techniques for low-voltage low-power electronics

    NARCIS (Netherlands)

    Serdijn, W.A.; Verhoeven, C.J.M.; Van Roermund, A.H.M.

    1995-01-01

    Analog IC Techniques lor Low-Voltage Low Power Electronics addresses many very important, but recent, techniques which enable electronics to operate at a low supply voltage and consume a minimum amount of power. Apart from investigations at the device, circuit and system levels, the book provides a

  11. Analog IC techniques for low-voltage low-power electronics

    NARCIS (Netherlands)

    Serdijn, W.A.; Verhoeven, C.J.M.; Van Roermund, A.H.M.

    1995-01-01

    Analog IC Techniques lor Low-Voltage Low Power Electronics addresses many very important, but recent, techniques which enable electronics to operate at a low supply voltage and consume a minimum amount of power. Apart from investigations at the device, circuit and system levels, the book provides a

  12. Experimental evaluation of envelope tracking techniques for voltage disturbances

    Energy Technology Data Exchange (ETDEWEB)

    Marei, Mostafa I. [Electrical Power and Machines Dept., Faculty of Engineering, Ain Shams University, 1 El-Sarayat St., Abbasia, 11517 Cairo (Egypt); El-Saadany, Ehab F.; Salama, Magdy M.A. [Electrical and Computer Engineering Dept., University of Waterloo, 200 University Avenue West, Waterloo, ON (Canada)

    2010-03-15

    In this paper a digital signal processor (DSP) based real time voltage envelope tracking system is developed and examined. The ADAptive LINEar neuron (ADALINE) and the Recursive Least Square (RLS) algorithms are adopted for envelope tracking. The proposed ADALINE and RLS algorithms give accurate results even under rapid dynamic changes. The paper investigates the effects of different parameters on the performance of the ADALINE algorithm and that of the RLS algorithm. The experimental system is cantered around a Texas Instrument 16 bit fixed-point arithmetic (TMS320LF2407A) evaluation board. Both the ADALINE and the RLS tracking algorithms are developed using the DSP-assembly language. A simple voltage flicker generator is implemented to produce various voltage disturbances. Extensive tests of the proposed envelope tracking algorithms are conducted to evaluate their dynamic performance. (author)

  13. Process, Voltage and Temperature Compensation Technique for Cascode Modulated PAs

    DEFF Research Database (Denmark)

    Sira, Daniel; Larsen, Torben

    2013-01-01

    This paper presents a process, voltage and temperature (PVT) compensation method for a cascode modulated polar power amplifier (PA). It is shown that it is possible to create a baseband replica circuit of the PA that has the same AM-AM nonlinearity as the PA itself. The replica circuit, that repr......This paper presents a process, voltage and temperature (PVT) compensation method for a cascode modulated polar power amplifier (PA). It is shown that it is possible to create a baseband replica circuit of the PA that has the same AM-AM nonlinearity as the PA itself. The replica circuit...

  14. High-Mixed-Voltage Analog and RF Circuit Techniques for Nanoscale CMOS

    CERN Document Server

    Mak, Pui-In

    2012-01-01

    This book presents high-/mixed-voltage analog and radio frequency (RF) circuit techniques for developing low-cost multistandard wireless receivers in nm-length CMOS processes.  Key benefits of high-/mixed-voltage RF and analog CMOS circuits are explained, state-of-the-art examples are studied, and circuit solutions before and after voltage-conscious design are compared. Three real design examples are included, which demonstrate the feasibility of high-/mixed-voltage circuit techniques.    Provides a valuable summary and real case studies of the state-of-the-art in high-/mixed-voltage circuits and systems; Includes novel high-/mixed-voltage analog and RF circuit techniques – from concept to practice; Describes the first high-voltage-enabled mobile-TVRF front-end in 90nm CMOS and the first mixed-voltage full-band mobile-TV Receiver in 65nm CMOS; Demonstrates the feasibility of high-/mixed-voltage circuit techniques with real design examples.  

  15. High voltage magnetic pulse generation using capacitor discharge technique

    Directory of Open Access Journals (Sweden)

    M. Rezal

    2014-12-01

    Full Text Available A high voltage magnetic pulse is designed by applying an electrical pulse to the coil. Capacitor banks are developed to generate the pulse current. Switching circuit consisting of Double Pole Double Throw (DPDT switches, thyristor, and triggering circuit is developed and tested. The coil current is measured using a Hall-effect current sensor. The magnetic pulse generated is measured and tabulated in a graph. Simulation using Finite Element Method Magnetics (FEMM is done to compare the results obtained between experiment and simulation. Results show that increasing the capacitance of the capacitor bank will increase the output voltage. This technology can be applied to areas such as medical equipment, measurement instrument, and military equipment.

  16. Carrier-Based Common Mode Voltage Control Techniques in Three-Level Diode-Clamped Inverter

    Directory of Open Access Journals (Sweden)

    Pradyumn Chaturvedi

    2012-01-01

    Full Text Available Switching converters are used in electric drive applications to produce variable voltage, variable frequency supply which generates harmful large dv/dt and high-frequency common mode voltages (CMV. Multilevel inverters generate lower CMV as compared to conventional two-level inverters. This paper presents simple carrier-based technique to control the common mode voltages in multilevel inverters using different structures of sine-triangle comparison method such as phase disposition (PD, phase opposition disposition (POD by adding common mode voltage offset signal to actual reference voltage signal. This paper also presented the method to optimize the magnitude of this offset signal to reduce CMV and total harmonic distortion in inverter output voltage. The presented techniques give comparable performance as obtained in complex space vector-based control strategy, in terms of number of commutations, magnitude, and rate of change of CMV and harmonic profile of inverter output voltage. Simulation and experimental results presented confirm the effectiveness of the proposed techniques to control the common mode voltages.

  17. Performance of two modified optimization techniques for power system voltage stability problems

    Directory of Open Access Journals (Sweden)

    S. Harish Kiran

    2016-09-01

    Full Text Available The development of optimization techniques in power system is to determine the sizing of Flexible AC Transmission System (FACTS devices such as Unified Power Flow Series Compensator (UPFC controller in improving the voltage stability and bus voltage margin. An attempt is made to modify the Particle Swarm Optimization (PSO and Artificial Bee Colony (ABC with Hybrid-Genetic Algorithm (H-GA for determination of sizing of the device. Fast Voltage Stability Index (FVSI is used to identify the location of the device to be connected. The proposed methods are implemented in IEEE 30 Bus system and its results are tabulated for each technique.

  18. Techniques for detecting proximity to voltage collapse in AC/DC systems

    Energy Technology Data Exchange (ETDEWEB)

    Canizares, Claudio A. [Escuela Politecnica Nacional, Quito (Ecuador); Long, Willis F.; Alvarado, Fernando L.; DeMarco, CChristopher L. [Wisconsin Univ., Madison, WI (United States)

    1992-12-31

    This paper describes three different techniques to detect proximity to voltage collapse (saddle-node bifurcation) in AC/DC systems; namely, direct (point of collapse) methods, continuation methods, and transient energy function methods. These techniques are compared among them, and also against the voltage sensitivity factor method using a 173 bus ac/dc test system. Various operational conditions are considered for this test system, so that transfer capabilities between areas and the effects of HVDC links can be analysed from the point of view of voltage collapse. 24 refs., 7 figs.

  19. Voltage-sensitive dye recording from axons, dendrites and dendritic spines of individual neurons in brain slices.

    Science.gov (United States)

    Popovic, Marko; Gao, Xin; Zecevic, Dejan

    2012-11-29

    Understanding the biophysical properties and functional organization of single neurons and how they process information is fundamental for understanding how the brain works. The primary function of any nerve cell is to process electrical signals, usually from multiple sources. Electrical properties of neuronal processes are extraordinarily complex, dynamic, and, in the general case, impossible to predict in the absence of detailed measurements. To obtain such a measurement one would, ideally, like to be able to monitor, at multiple sites, subthreshold events as they travel from the sites of origin on neuronal processes and summate at particular locations to influence action potential initiation. This goal has not been achieved in any neuron due to technical limitations of measurements that employ electrodes. To overcome this drawback, it is highly desirable to complement the patch-electrode approach with imaging techniques that permit extensive parallel recordings from all parts of a neuron. Here, we describe such a technique - optical recording of membrane potential transients with organic voltage-sensitive dyes (V(m)-imaging) - characterized by sub-millisecond and sub-micrometer resolution. Our method is based on pioneering work on voltage-sensitive molecular probes (2). Many aspects of the initial technology have been continuously improved over several decades (3, 5, 11). Additionally, previous work documented two essential characteristics of V(m)-imaging. Firstly, fluorescence signals are linearly proportional to membrane potential over the entire physiological range (-100 mV to +100 mV; (10, 14, 16)). Secondly, loading neurons with the voltage-sensitive dye used here (JPW 3028) does not have detectable pharmacological effects. The recorded broadening of the spike during dye loading is completely reversible (4, 7). Additionally, experimental evidence shows that it is possible to obtain a significant number (up to hundreds) of recordings prior to any detectable

  20. A Hybrid Islanding Detection Technique Using Average Rate of Voltage Change and Real Power Shift

    DEFF Research Database (Denmark)

    Mahat, Pukar; Chen, Zhe; Bak-Jensen, Birgitte

    2009-01-01

    technique is proposed to solve this problem. An average rate of voltage change (passive technique) has been used to initiate a real power shift (active technique), which changes the eal power of distributed generation (DG), when the passive technique cannot have a clear discrimination between islanding......The mainly used islanding detection techniques may be classified as active and passive techniques. Passive techniques don't perturb the system but they have larger nondetection znes, whereas active techniques have smaller nondetection zones but they perturb the system. In this paper, a new hybrid...

  1. Suppression of Spiral Waves by Voltage Clamp Techniques in a Conductance-Based Cardiac Tissue Model

    Institute of Scientific and Technical Information of China (English)

    YU Lian-Chun; MA Jun; ZHANG Guo-Yong; CHEN Yong

    2008-01-01

    A new control method is proposed to control the spatio-temporal dynamics in excitable media, which is described by the Morris-Lecar cells model. It is confirmed that successful suppression of spiral waves can be obtained by spatially clamping the membrane voltage of the excitable cells. The low voltage clamping induces breakup of spiral waves and the fragments are soon absorbed by low voltage obstacles, whereas the high voltage clamping generates travel waves that annihilate spiral waves through collision with them. However, each method has its shortcomings. Furthermore, a two-step method that combines both low and high voltage clamp techniques is then presented as a possible way of out this predicament.

  2. A test technique for measuring lightning-induced voltages on aircraft electrical circuits

    Science.gov (United States)

    Walko, L. C.

    1974-01-01

    The development of a test technique used for the measurement of lightning-induced voltages in the electrical circuits of a complete aircraft is described. The resultant technique utilizes a portable device known as a transient analyzer capable of generating unidirectional current impulses similar to lightning current surges, but at a lower current level. A linear relationship between the magnitude of lightning current and the magnitude of induced voltage permitted the scaling up of measured induced values to full threat levels. The test technique was found to be practical when used on a complete aircraft.

  3. A Review of EMG recording technique

    Directory of Open Access Journals (Sweden)

    Imteyaz Ahmad

    2012-02-01

    Full Text Available Electromayogram signals are frequently used to evaluate muscle injuries. They are also used extensively in biofeedback training equipment. This study investigates the electrical activity of muscles and the interrelationship of muscles and nerve fibers. Muscle potentials are observed and measured on an oscilloscope.By placing electrodes in to a skeletal muscle we can monitor the electrical activity of the muscle. EMG is used to detect muscular disorder along with muscular abnormalities caused by other system disease such as nerve dysfunction. Neuro muscular disorder also can be known with the help of EMG. EMG is also used for diagnose of Neuro muscular performance. It is observed that there is alternating relationship between the contractions of biceps and triceps the relaxation of one forces the contraction of the other. EMG signals have been recorded atthe various positions like point Biceps, point triceps and point contractions. The frequency range of the muscle spikes covers a bandwidth from DC to over 2 KHz. This recording belongs to a normal subject.

  4. Cavity techniques for holographic data storage recording.

    Science.gov (United States)

    Miller, Bo E; Takashima, Yuzuru

    2016-03-21

    Conventionally, reading and writing of data holograms utilizes a fraction of the light power because of a trade off in write and read efficiencies. This system constraint can be mitigated by applying a resonator cavity. Cavities enable more efficient use of the available light leading to enhanced read and write data rates with no additional energy cost. This enhancement is inversely related to diffraction efficiency, so these techniques work well for large capacity holographic data storage having low diffraction efficiency. The enhancement in write data transfer rate is evaluated by writing plane wave holograms and image bearing holograms in Fe:LiNbO3 with a 532 nm wavelength laser. We confirmed 1.2 times enhancement in write data rate, out of a 1.4 theoretical maximum for materials absorption of 16%.

  5. A new curvature compensation technique for CMOS voltage reference using |VGS| and ΔVBE

    Science.gov (United States)

    Xuemin, Li; Mao, Ye; Gongyuan, Zhao; Yun, Zhang; Yiqiang, Zhao

    2016-05-01

    A new mixed curvature compensation technique for CMOS voltage reference is presented, which resorts to two sub-references with complementary temperature characteristics. The first sub-reference is the source-gate voltage |VGS|p of a PMOS transistor working in the saturated region. The second sub-reference is the weighted sum of gate-source voltages |VGS|n of NMOS transistors in the subthreshold region and the difference between two base-emitter voltages ΔVBE of bipolar junction transistors (BJTs). The voltage reference implemented utilizing the proposed curvature compensation technique exhibits a low temperature coefficient and occupies a small silicon area. The proposed technique was verified in 0.18 μm standard CMOS process technology. The performance of the circuit has been measured. The measured results show a temperature coefficient as low as 12.7 ppm/°C without trimming, over a temperature range from -40 to 120 °C, and the current consumption is 50 μA at room temperature. The measured power-supply rejection ratio (PSRR) is -31.2 dB @ 100 kHz. The circuit occupies an area of 0.045 mm2. Project supported by the National Natural Science Foundation of China (No. 61376032).

  6. Voltage Stabilization of a Wind Turbine with STATCOM Using Intelligent Control Techniques

    Directory of Open Access Journals (Sweden)

    S. A. Gawish

    2016-03-01

    Full Text Available Application of FACTS controller called Static Synchronous Compensator STATCOM to improve the performance of power grid with Wind System is investigated. The essential feature of the STATCOM is that it has the ability to absorb or inject fastly reactive power with power grid. Therefore the voltage regulation of the power grid with STATCOM FACTS device is achieved. Moreover restoring the stability of the wind system at suddenly step up or down in wind speed is obtained with STATCOM. This paper describes a complete simulation of voltage regulation of a wind system using STATCOM. Conventional control technique as proportional plus integral controller , and intelligent techniques as FLC and ANFIS are used in this work. The control technique is performed using MATLAB package software. The dynamic response of uncontrolled system is also investigated under wide range of disturbances. The voltage regulation by using STATCOM whose output is varied so as to maintain or control output voltage in the system. The dynamic response of controlled system is shown and comparison between the uncontrolled system and the controlled system is described to assure the validity of the proposed controller. Also comparison between the proposed control methods scheme is presented. To validate the powerful of the STATCOM FACTS controllers, the studied power system is simulated and subjected to different severe disturbances. The results prove the effectiveness of the proposed STATCOM controller in terms of fast damping the power system oscillations and restoring the power system stability and voltage.

  7. Bottom-series coupled quadrature VCO using the inductive gate voltage boosting technique

    Science.gov (United States)

    Jang, Sheng-Lyang; Chou, Li-Te

    2013-09-01

    This article presents a new low-voltage bottom-series coupled quadrature voltage-controlled oscillator (QVCO), which consists of two n-core cross-coupled VCOs with the bottom-series coupling transistors. The low-voltage operation is obtained via an inductive gate voltage boosting technique. The proposed CMOS QVCO has been implemented with the TSMC 0.18 µm CMOS technology and the die area is 0.897 × 0.767 mm2. At the supply voltage of 0.7 V, the total power consumption is 1.5 mW. The free-running frequency of the QVCO is tuneable from 3.77 to 4.12 GHz as the tuning voltage is varied from 0.0 to 0.7 V. The measured phase noise at 1 MHz frequency offset is -123.35 dBc/Hz at the oscillation frequency of 4.12 GHz and the figure of merit of the proposed QVCO is -193.5 dBc/Hz.

  8. Harmonic elimination technique for a single-phase multilevel converter with unequal DC link voltage levels

    DEFF Research Database (Denmark)

    Ghasemi, N.; Zare, F.; Boora, A.A.

    2012-01-01

    on the output voltage quality by reducing its total harmonic distortion, which must take into consideration for some applications such as uninterruptable power supply, motor drive systems and piezoelectric transducer excitation. In order to verify the proposed modulation technique, MATLAB simulations...

  9. A zero-voltage switching technique for minimizing the current-source power of implanted stimulators.

    Science.gov (United States)

    Çilingiroğlu, Uğur; İpek, Sercan

    2013-08-01

    The current-source power of an implanted stimulator is reduced almost to the theoretical minimum by driving the electrodes directly from the secondary port of the inductive link with a dedicated zero-voltage switching power supply. A feedback loop confined to the secondary of the inductive link adjusts the timing and conduction angle of switching to provide just the right amount of supply voltage needed for keeping the current-source voltage constant at or slightly above the compliance limit. Since drive is based on current rather than voltage, and supply-voltage update is near real-time, the quality of the current pulses is high regardless of how the electrode impedance evolves during stimulation. By scaling the switching frequency according to power demand, the technique further improves overall power consumption of the stimulator. The technique is implemented with a very simple control circuitry comprising a comparator, a Schmitt trigger and a logic gate of seven devices in addition to an on-chip switch and an off-chip capacitor. The power consumed by the proposed supply circuit itself is no larger than what the linear regulator of a conventional supply typically consumes for the same stimulation current. Still, the sum of supply and current-source power is typically between 20% and 75% of the conventional source power alone. Functionality of the proposed driver is verified experimentally on a proof-of-concept prototype built with 3.3 V devices in a 0.18 μm CMOS technology.

  10. ZnO films deposited by optimized PLD technique with bias voltages

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Hiroyuki; Shitara, Tamae; Komiyama, Takao; Chonan, Yasunori; Aoyama, Takashi [Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya Ebinokuchi, 015-0055 Yuri-Honjo (Japan)

    2010-02-15

    The pulsed laser deposition (PLD) technique with bias voltage application for formation of high quality ZnO films was investigated. Oxygen ambient in the PLD chamber significantly decreased the photoluminescence (PL) intensity of near band edge (NBE) emission. Then, instead of using oxygen ambient, the PLD technique with bias voltage application was optimized to attain the stoichiometric composition of the ZnO films. As the deposition temperature was increased, the X-ray spectrum width diffracted from the (0002) planes was decreased and it showed a minimum value at 700 C. The PL intensity of the NBE emission also had its maximum value for the film deposited at 700 C. For the ZnO films deposited at 700 C, the X-ray spectrum width showed the minimum value under a bias voltage of -50 V. The PL intensity of the NBE emission also had a maximum value under the same bias voltage. Thus, ZnO films deposited under a bias voltage of -50 V at 700 C had strong NBE emission intensities. These results could be explained not only by attaining the stoichiometric composition of the ZnO film but also by decreasing the number of high energy O{sup 2-} ions which caused non-radiative recombination centers in the film. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. High impulse voltage and current measurement techniques fundamentals, measuring instruments, measuring methods

    CERN Document Server

    Schon, Klaus

    2013-01-01

    Equipment to be installed in electric power-transmission and distribution systems must pass acceptance tests with standardized high-voltage or high-current test impulses which simulate the stress on the insulation caused by external lightning discharges and switching operations in the grid. High impulse voltages and currents are also used in many other fields of science and engineering for various applications. Therefore, precise impulse-measurement techniques are necessary, either to prevent an over- or understressing of the insulation or to guarantee the effectiveness and quality of the application. The book deals with: principal generator circuits for generating high-voltage and high-current impulses measuring systems and their calibration according to IEC 60060 and IEC 62475 methods of estimating uncertainties of measurement mathematical and experimental basis for characterizing the transfer behavior of spatially extended systems used for measuring fast transients. This book is intended for engineers and ...

  12. Efficiency Optimization by Considering the High Voltage Flyback Transformer Parasitics using an Automatic Winding Layout Technique

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Schneider, Henrik; Zhang, Zhe;

    2015-01-01

    .The energy efficiency is optimized using a proposed new automatic winding layout (AWL) technique and a comprehensive loss model.The AWL technique generates a large number of transformer winding layouts.The transformer parasitics such as dc resistance, leakage inductance and self-capacitance are calculated...... for each winding layout.An optimization technique is formulated to minimize the sum of energy losses during charge and discharge operations.The efficiency and energy loss distribution results from the optimization routine provide a deep insight into the high voltage transformer designand its impact...

  13. Investigation of Leakage Current Waveforms Recorded in a Coastal High Voltage Substation

    Directory of Open Access Journals (Sweden)

    E. Thalassinakis

    2011-06-01

    Full Text Available Leakage current monitoring is a widely employed technique to monitor the performance of outdoor insulation. The evaluation of leakage current waveforms recorded in the field, offers significant information since insulation’s performance is strongly linked with local conditions, and the waveforms’ shape correlate to different types of surface activity. In this paper, an investigation of leakage current waveforms recorded in a 150 kV coastal Substations suffering which suffers intense marine pollution is presented. Investigation of the recorded waveforms verified the basic waveform shapes described in the literature. Further, several variations of the basic types and complex waveforms, as well as field related waveforms, are presented. The need for added categorization criteria in the case of field measurements is discussed.

  14. A CMOS frontend chip for implantable neural recording with wide voltage supply range

    Science.gov (United States)

    Jialin, Liu; Xu, Zhang; Xiaohui, Hu; Yatao, Guo; Peng, Li; Ming, Liu; Bin, Li; Hongda, Chen

    2015-10-01

    A design for a CMOS frontend integrated circuit (chip) for neural signal acquisition working at wide voltage supply range is presented in this paper. The chip consists of a preamplifier, a serial instrumental amplifier (IA) and a cyclic analog-to-digital converter (CADC). The capacitive-coupled and capacitive-feedback topology combined with MOS-bipolar pseudo-resistor element is adopted in the preamplifier to create a -3 dB upper cut-off frequency less than 1 Hz without using a ponderous discrete device. A dual-amplifier instrumental amplifier is used to provide a low output impedance interface for ADC as well as to boost the gain. The preamplifier and the serial instrumental amplifier together provide a midband gain of 45.8 dB and have an input-referred noise of 6.7 μVrms integrated from 1 Hz to 5 kHz. The ADC digitizes the amplified signal at 12-bits precision with a highest sampling rate of 130 kS/s. The measured effective number of bits (ENOB) of the ADC is 8.7 bits. The entire circuit draws 165 to 216 μA current from the supply voltage varied from 1.34 to 3.3 V. The prototype chip is fabricated in the 0.18-μm CMOS process and occupies an area of 1.23 mm2 (including pads). In-vitro recording was successfully carried out by the proposed frontend chip. Project supported by the National Natural Science Foundation of China (Nos. 61474107, 61372060, 61335010, 61275200, 61178051) and the Key Program of the Chinese Academy of Sciences (No. KJZD-EW-L11-01).

  15. Low-Voltage Process-Compensated VCO with On-Chip Process Monitoring and Body-Biasing Circuit Techniques

    OpenAIRE

    Ueno, Ken; Hirose, Tetsuya; Asai, Tetsuya; Amemiya, Yoshihito

    2009-01-01

    A voltage-controlled oscillator (VCO) tolerant to process variations at lower supply voltage was proposed. The circuit consists of an on-chip threshold-voltage-monitoring circuit, a current-source circuit, a body-biasing control circuit, and the delay cells of the VCO. Because variations in low-voltage VCO frequency are mainly determined by that of the current in delay cells. a current-compensation technique was adopted by using an on-chip threshold-voltage-monitoring circuit and body-biasing...

  16. Membrane voltage differently affects mIPSCs and current responses recorded from somatic excised patches in rat hippocampal cultures.

    Science.gov (United States)

    Pytel, Maria; Mozrzymas, Jerzy W

    2006-01-30

    Recent analysis of current responses to exogenous GABA applications recorded from excised patches indicated that membrane voltage affected the GABAA receptor gating mainly by altering desensitization and binding [M. Pytel, K. Mercik, J.W. Mozrzymas, Membrane voltage modulates the GABAA receptor gating in cultured rat hippocampal neurons, Neuropharmacology, in press]. In order investigate the impact of such voltage effect on GABAA receptors in conditions of synaptic transmission, mIPSCs and current responses to rapid GABA applications were recorded from the same culture of rat hippocampal neurons. We found that I-V relationship for mIPSCs amplitudes showed a clear outward rectification while for current responses an inward rectification was seen, except for very low GABA concentrations. A clear shift in amplitude cumulative distributions indicated that outward rectification resulted from the voltage effect on the majority of mIPSCs. Moreover, the decaying phase of mIPSCs was clearly slowed down at positive voltages and this effect was represented by a shift in cumulative distributions of weighted decaying time constants. In contrast, deactivation of current responses was only slightly affected by membrane depolarization. These data indicate that the mechanisms whereby the membrane voltage modulates synaptic and extrasynaptic receptors are qualitatively different but the mechanism underlying this difference is not clear.

  17. Low voltage integrated optics electro-optical modulator applied to optical voltage transformer based on WLI technique

    Science.gov (United States)

    Santos, J. C.; Rubini, J.; Silva, L. P. C.; Caetano, R. E.

    2015-09-01

    The use of two electro-optical modulators linked in series, one for sensing and one for recovering signals, was formerly presented by some of the authors as a solution for interrogation of optical fiber sensor systems based on WLI method. A key feature required from such systems is that half-wave voltage (Vπ) of recovering modulator must be as small as possible. Aiming at meeting this requirement, in this paper it is presented the use of an unbalanced Michelson Interferometer implemented using an integrated optics component as recover interferometer in an optical voltage transformer intended for high voltage measurements.

  18. Simulation Investigation of SPWM, THIPWM and SVPWM Techniques for Three Phase Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Zulkifilie Bin Ibrahim

    2014-03-01

    Full Text Available Pulse width modulation (PWM technique is one of the vital issues for power electronic circuit control. A number of Pulse width modulation (PWM techniques are increasingly applied in many new industrial applications that require superior performance. The most widely applied PWM technique for three-phase voltage source inverters are Sine Pulse Width Modulation (SPWM, Third Harmonic Injection Pulse Width Modulation (THIPWM and Space Vector Pulse Width Modulation (SVPWM. SPWM is the most simple modulation technique that can realize easily in analog circuit. However, it has some drawbacks such as higher total harmonic distortion (THD, lower switching frequency and not capable in over modulation region. THIPWM and SVPWM both provide better THD compared to SPWM. SVPWM shows lower THD in over modulation region and in high frequency application compared to THIPWM. These three techniques are discussed, analyzed and compared in terms of modulation index, switching frequency and inverter input voltage in this paper. The modeling and simulation for all PWM techniques have been done by using MATLAB/SIMULINK and Origin 6.1. From the simulation results, SVPWM shows the best performance and meet IEEE 519 standard of current harmonics level.

  19. A numerical approach to ion channel modelling using whole-cell voltage-clamp recordings and a genetic algorithm.

    Directory of Open Access Journals (Sweden)

    Meron Gurkiewicz

    2007-08-01

    Full Text Available The activity of trans-membrane proteins such as ion channels is the essence of neuronal transmission. The currently most accurate method for determining ion channel kinetic mechanisms is single-channel recording and analysis. Yet, the limitations and complexities in interpreting single-channel recordings discourage many physiologists from using them. Here we show that a genetic search algorithm in combination with a gradient descent algorithm can be used to fit whole-cell voltage-clamp data to kinetic models with a high degree of accuracy. Previously, ion channel stimulation traces were analyzed one at a time, the results of these analyses being combined to produce a picture of channel kinetics. Here the entire set of traces from all stimulation protocols are analysed simultaneously. The algorithm was initially tested on simulated current traces produced by several Hodgkin-Huxley-like and Markov chain models of voltage-gated potassium and sodium channels. Currents were also produced by simulating levels of noise expected from actual patch recordings. Finally, the algorithm was used for finding the kinetic parameters of several voltage-gated sodium and potassium channels models by matching its results to data recorded from layer 5 pyramidal neurons of the rat cortex in the nucleated outside-out patch configuration. The minimization scheme gives electrophysiologists a tool for reproducing and simulating voltage-gated ion channel kinetics at the cellular level.

  20. Dragon-I injector based on the induction voltage adder technique

    Directory of Open Access Journals (Sweden)

    Zhang Kaizhi

    2006-08-01

    Full Text Available The Dragon-I injector based on the induction voltage adder technique is introduced. Twelve ferrite loaded induction cells are connected in a series through central conducting stalks to achieve a pulsed voltage higher than 3.5 MV across the diode. Electrons are extracted from the velvet emitter and guided through the anode pipe by the magnets placed inside the cathode and anode shrouds. Measurements at the exit of injector show that, with an electric field of 200  kV/cm near the velvet surface and suitable magnetic field distribution, an electron beam up to 2.8 kA can be obtained with a normalized emittance of 1040π   mm mrad, and energy spread of 2.1% (3σ around the central energy of 3.5 MeV.

  1. Analysis of cutting-edge techniques in the high voltage and high power adjustable speed drive systems

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The high voltage and high power adjustable speed drive (ASD) system is one of the most attractive fields in power electronics, and it is also a very crucial technique for energy saving and emission reduction. This paper discussed and analyzed the main cutting-edge knowledge and issues in the process of exploiting the high voltage and high power ASD system.

  2. Video recording trauma resuscitations: an effective teaching technique.

    Science.gov (United States)

    Hoyt, D B; Shackford, S R; Fridland, P H; Mackersie, R C; Hansbrough, J F; Wachtel, T L; Fortune, J B

    1988-04-01

    Since the initial hour after injury is the most crucial time for trauma patients, resuscitation technique is of vital importance. Standardized courses for first-hour management (ATLAS) have been widely accepted. A teaching format based upon video recording of every resuscitation has been developed. Tapes are reviewed by the staff and by the individuals involved in a particular resuscitation. In a weekly resuscitation review conference, actual footage is presented to the trauma team members, specific aspects of a resuscitation are critiqued, and supplemental didactic information is presented. Legal problems have been avoided by making the review and conference a part of the quality assurance process. Patient anonymity is preserved by positioning the video camera at the foot of the resuscitation bed. Tapes are erased after each conference. Video recording allows analysis of: 1) priorities during the resuscitation; 2) cognitive integration of the workup by the team leader; 3) physical integration of the workup by the team leader; 4) team member adherence to assigned responsibilities, resuscitation time, errors or breaks in technique; and 5) behavior change over time. In 3 1/2 years, more than 2,500 resuscitations have been recorded. Over a 3-month period, average resuscitation time to definitive care decreased for age- and injury severity-matched patient groups cared for by one team. Resuscitations have become more efficient and adherence to assigned responsibilities better. Weekly review of resuscitation contributes to improved technique and trauma care.

  3. Sizing of SRAM Cell with Voltage Biasing Techniques for Reliability Enhancement of Memory and PUF Functions

    Directory of Open Access Journals (Sweden)

    Chip-Hong Chang

    2016-08-01

    Full Text Available Static Random Access Memory (SRAM has recently been developed into a physical unclonable function (PUF for generating chip-unique signatures for hardware cryptography. The most compelling issue in designing a good SRAM-based PUF (SPUF is that while maximizing the mismatches between the transistors in the cross-coupled inverters improves the quality of the SPUF, this ironically also gives rise to increased memory read/write failures. For this reason, the memory cells of existing SPUFs cannot be reused as storage elements, which increases the overheads of cryptographic system where long signatures and high-density storage are both required. This paper presents a novel design methodology for dual-mode SRAM cell optimization. The design conflicts are resolved by using word-line voltage modulation, dynamic voltage scaling, negative bit-line and adaptive body bias techniques to compensate for reliability degradation due to transistor downsizing. The augmented circuit-level techniques expand the design space to achieve a good solution to fulfill several otherwise contradicting key design qualities for both modes of operation, as evinced by our statistical analysis and simulation results based on complementary metal–oxide–semiconductor (CMOS 45 nm bulk Predictive Technology Model.

  4. A Low Phase Noise CMOS Quadrature Voltage Control Oscillator Using Clock Gated Technique

    Directory of Open Access Journals (Sweden)

    Jothi Baskar A

    2015-06-01

    Full Text Available This project presents the low phase noise cmos quadrature voltage control oscillator using clock gating technique. Here the colpitts vco is used to split the capacitance in the Qvco circuit producing quadrature output. The startup condition in the oscillator is improved by using enhancement [12].This QVCO performs the operation anti phase injection locking fordevice reuse [8]. The new clock gating technique is used to reduce the power with thepower supply 1.5v. The QVCO uses a 0.5mwith phase error of 0.4 and exhibits a phase noise of -118dBc/HZ at 1MHZ offset at the centre frequency of 500MHZ. Index terms: current switching, clock gating, phase noise, Qvco

  5. Analysis of Discontinuous Space Vector PWM Techniques for a Seven-Phase Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Mohd. Arif Khan

    2012-03-01

    Full Text Available This paper presents discontinuous space vector PWM (DPWM techniques for a seven-phase voltage source inverter (VSI. Space vector model of a seven-phase VSI shows that there exist 128 space vectors with different lengths and maps into fourteen sided polygons. A number of possibilities could arise to implement modulation of inverter legs due to large number of available space voltage vectors. Two strategies are adopted here; one utilising large and two middle sets of space vectors to implement discontinuous space vector PWM. Clamping of legs of inverter to either positive or negative dc bus leads to discontinuity in the switching and consequently offers reduced switching loss modulation strategy. A significant reduction in switching losses can be achieved while employing DPWM in a seven-phase VSI. A generalised method is also proposed to realize the DPWM in a seven-phase VSI. Comparison of continuous and discontinuous PWM is presented in terms of switching current ripple. The experimental set-up is illustrated and the experimental results are presented.

  6. Beaming teaching application: recording techniques for spatial xylophone sound rendering

    DEFF Research Database (Denmark)

    Markovic, Milos; Madsen, Esben; Olesen, Søren Krarup;

    2012-01-01

    BEAMING is a telepresence research project aiming at providing a multimodal interaction between two or more participants located at distant locations. One of the BEAMING applications allows a distant teacher to give a xylophone playing lecture to the students. Therefore, rendering of the xylophone...... played at student's location is required at teacher's site. This paper presents a comparison of different recording techniques for a spatial xylophone sound rendering. Directivity pattern of the xylophone was measured and spatial properties of the sound field created by a xylophone as a distributed sound...

  7. Noise reduction techniques for the restoration of musical recordings

    Science.gov (United States)

    Cappe, Olivier

    The evaluation of short time spectral attenuation techniques using a simplified model of standard noise suppression rules and with elementary test signals is assessed. Signal distortions induced by the restoration process are evaluated analytically, and their audibility is addressed by use of classic psychoacoustics results. Phenomena observed experimentally in previous studies, such as the modification of timbre, the appearance of modulations, and the spreading of transients, are brought to light. Drawing from these results, a noise reduction technique intended for enhancing musical signals is described. In the first step, the noisy signal is analyzed by use of a medium frequency resolution short time transform. The restoration then takes place in each subband in two different ways according to the nature of the subband signal: the processing is carried out block by block when steady signal components are detected, or locally otherwise. This approach was successfully applied to several musical recordings yielding promising results.

  8. Pixel-level A/D conversion using voltage reset technique

    Institute of Scientific and Technical Information of China (English)

    Li Minzeng; Li Fule; Zhang Chun; Wang Zhihua

    2014-01-01

    This paper presents a 50 Hz 15-bit analog-to-digital converter (ADC) for pixel-level implementation in CMOS image sensors.The ADC is based on charge packets counting and adopts a voltage reset technique to inject charge packets.The core circuit for charge/pulse conversion is specially optimized for low power,low noise and small area.An experimental chip with ten pixel-level ADCs has been fabricated and tested for verification.The measurement result shows a standard deviation of 1.8 LSB for full-scale output.The ADC has an area of 45 × 45μm2 and consumes less than 2 μW in a standard 1P-6M 0.18μm CMOS process.

  9. An exploding foil shockwave technique for magnetic flux compression and high voltage pulse generation

    CERN Document Server

    Goh, S E

    2002-01-01

    This thesis describes a novel electromagnetic shockwave technique for use in compressing magnetic flux and to serve as the basis for a new approach to producing fast-rising voltage pulses with amplitudes of several hundred kV. The shockwave is produced by an exploding foil driven electric gun that accelerates a Mylar flyer to impact with a sample of aluminium powder. Both Japanese and Russian researchers have previously published experimental results for shockwave magnetic flux compression using an explosive driver. The present research considers replacing the explosive energy of this driver by the electrostatic energy stored in a capacitor bank, thereby enabling experiments to be performed in a laboratory environment. Differences in performance that arise from the use of explosive and electrical driver are examined. A conventional electric gun system in planar geometry is developed to study the insulator-to-metallic transition in shock-compressed aluminium powder. This provides data on the conducting shock f...

  10. Analysis of cutting-edge techniques in the high voltage and high power adjustable speed drive systems

    Institute of Scientific and Technical Information of China (English)

    ZHAO ZhengMing; BAI Hua; YUAN LiQiang

    2009-01-01

    The high voltage and high power adjustable speed drive (ASD) system is one of the most attractive fields in power electronics, and it is also a very crucial technique for energy saving and emission re-duction. This paper discussed and analyzed the main cutting-edge knowledge and issues in the proc-ess of exploiting the high voltage and high power ASD system.

  11. A Survey of Non-conventional Techniques for Low-voltage Low-power Analog Circuit Design

    Directory of Open Access Journals (Sweden)

    F. Khateb

    2013-06-01

    Full Text Available Designing integrated circuits able to work under low-voltage (LV low-power (LP condition is currently undergoing a very considerable boom. Reducing voltage supply and power consumption of integrated circuits is crucial factor since in general it ensures the device reliability, prevents overheating of the circuits and in particular prolongs the operation period for battery powered devices. Recently, non-conventional techniques i.e. bulk-driven (BD, floating-gate (FG and quasi-floating-gate (QFG techniques have been proposed as powerful ways to reduce the design complexity and push the voltage supply towards threshold voltage of the MOS transistors (MOST. Therefore, this paper presents the operation principle, the advantages and disadvantages of each of these techniques, enabling circuit designers to choose the proper design technique based on application requirements. As an example of application three operational transconductance amplifiers (OTA base on these non-conventional techniques are presented, the voltage supply is only ±0.4 V and the power consumption is 23.5 µW. PSpice simulation results using the 0.18 µm CMOS technology from TSMC are included to verify the design functionality and correspondence with theory.

  12. Flexible low-voltage organic integrated circuits with megahertz switching frequencies (Presentation Recording)

    Science.gov (United States)

    Zschieschang, Ute; Takimiya, Kazuo; Zaki, Tarek; Letzkus, Florian; Richter, Harald; Burghartz, Joachim N.; Klauk, Hagen

    2015-09-01

    A process for the fabrication of integrated circuits based on bottom-gate, top-contact organic thin-film transistors (TFTs) with channel lengths as short as 1 µm on flexible plastic substrates has been developed. In this process, all TFT layers (gate electrodes, organic semiconductors, source/drain contacts) are patterned with the help of high-resolution silicon stencil masks, thus eliminating the need for subtractive patterning and avoiding the exposure of the organic semiconductors to potentially harmful organic solvents or resists. The TFTs employ a low-temperature-processed gate dielectric that is sufficiently thin to allow the TFTs and circuits to operate with voltages of about 3 V. Using the vacuum-deposited small-molecule organic semiconductor 2,9-didecyl-dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (C10 DNTT), TFTs with an effective field-effect mobility of 1.2 cm2/Vs, an on/off current ratio of 107, a width-normalized transconductance of 1.2 S/m (with a standard deviation of 6%), and a signal propagation delay (measured in 11-stage ring oscillators) of 420 nsec per stage at a supply voltage of 3 V have been obtained. To our knowledge, this is the first time that megahertz operation has been achieved in flexible organic transistors at supply voltages of less than 10 V. In addition to flexible ring oscillators, we have also demonstrated a 6-bit digital-to-analog converter (DAC) in a binary-weighted current-steering architecture, based on TFTs with a channel length of 4 µm and fabricated on a glass substrate. This DAC has a supply voltage of 3.3 V, a circuit area of 2.6 × 4.6 mm2, and a maximum sampling rate of 100 kS/s.

  13. Electric current and voltage recordings on the myocardium during electrosurgical procedures in canines.

    Science.gov (United States)

    Selikowitz, S M; LaCourse, J R

    1987-03-01

    Voltage and current spectra were measured with probes placed directly on the canine myocardium during transurethral resection (TUR). It was determined that three factors may be related to potential cardiac effects during electrosurgical procedures: obvious low frequency components modulated from a center frequency of the electrosurgical generator; high current density due to high power setting during TUR, and duration of application of the cutting waveform.

  14. Comparative Analysis of PWM Techniques for Three Level Diode Clamped Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Zulkifilie Bin Ibrahim

    2014-07-01

    Full Text Available Multilevel inverters are increasingly being used in high-power medium voltage industrial drive applications due to their superior performance compared to conventional two-level inverters. Thre are a number of Pulse width modulation (PWM techniques applied in recent years. The most widely applied PWM techniques are Sine Pulse Width Modulation (SPWM and Space Vector Pulse Width Modulation (SVPWM.  SPWM is the most simple modulation technique that can realize easily in analog circuit.  However, it has some drawbacks such as higher total harmonic distortion (THD, lower effective DC utilization and lower switching frequency. Space vector pulse width modulation (SVPWM is widely used because of their easier digital realization and better DC bus utilization and lower THD. The complexity is due to the difficulty in determining the reference vector location, on times calculation, and switching states selection. This paper presents a simple SVPWM algorithm for diode clamped three level inverters based on standard two-level SVPWM which can easily determine the location of reference vector, calculate the on-times, the selection of switching states. Three level diode clamped inverter (3LDCI using space vector modulation technique has been modeled and simulated using MATLAB/SIMULINK and Origin 6.1 with a passive R-L load that can be extended to any level. Simulation results are presented to verify the proposed SVPWM control in terms of THD. The results are compared with conventional sinusoidal pulse width modulation (SPWM where SVPWM shows better performance than SPWM in terms of THD.

  15. Fingerprint technique for medium voltage relays and breakers makes maintenance superfluous; Fingerprint techniek maakt onnodig onderhoud overbodig

    Energy Technology Data Exchange (ETDEWEB)

    Krikke, K.; Peters, J.C.F.M. [Kenniscentrum Distributie Technologie KDT, PNEM, Den Bosch (Netherlands); Wilde, M. [Radiodetection Ltd., `s Heerenberg (Netherlands)

    1996-09-01

    The title technique will enable electric utilities to introduce condition based maintenance, improving quality and maintenance efficiency on the medium voltage network, giving the largest contribution to outages. The measurement equipment is developed by Kelman Ltd., based on an idea from an innovation project at one of the Dutch electric utility companies (PNEM). 6 figs., 6 refs.

  16. Dynamic Stability Improvement of Grid Connected DFIG Using Enhanced Field Oriented Control Technique for High Voltage Ride Through

    Directory of Open Access Journals (Sweden)

    V. N. Ananth Duggirala

    2015-01-01

    Full Text Available Doubly fed induction generator (DFIG is a better alternative to increased power demand. Modern grid regulations force DFIG to operate without losing synchronism during overvoltages called high voltage ride through (HVRT during grid faults. Enhanced field oriented control technique (EFOC was proposed in Rotor Side Control of DFIG converter to improve power flow transfer and to improve dynamic and transient stability. Further electromagnetic oscillations are damped, improved voltage mitigation and limit surge currents for sustained operation of DFIG during voltage swells. The proposed strategy has advantages such as improved reactive power control, better damping of electromagnetic torque oscillations, and improved continuity of voltage and current from stator and rotor to grid during disturbance. In EFOC technique, rotor flux reference changes its value from synchronous speed to zero during fault for injecting current at the rotor slip frequency. In this process, DC-Offset component of stator flux is controlled so that decomposition during overvoltage faults can be minimized. The offset decomposition of flux will be oscillatory in a conventional FOC, whereas in EFOC it is aimed to be quick damping. The system performance with overvoltage of 1.3 times, 1.62 times, and 2 times the rated voltage occurring is analyzed by using simulation studies.

  17. On the design of a low-voltage two-stage OTA using bulk-driven and positive feedback techniques

    Science.gov (United States)

    Khameh, Hassan; Shamsi, Hossein

    2012-09-01

    This article presents the design and simulation of a fully differential two-stage operational transconductance amplifier (OTA) in a 0.18 µm CMOS process with a 0.9 V supply voltage. For this purpose, both the bulk-driven and positive feedback techniques are employed. These techniques increase the DC gain by about 18.5 dB without consuming more power and changing the unity-gain bandwidth and phase margin of the OTA.

  18. Comparative Study of Online Open Circuit Voltage Estimation Techniques for State of Charge Estimation of Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Hicham Chaoui

    2017-04-01

    Full Text Available Online estimation techniques are extensively used to determine the parameters of various uncertain dynamic systems. In this paper, online estimation of the open-circuit voltage (OCV of lithium-ion batteries is proposed by two different adaptive filtering methods (i.e., recursive least square, RLS, and least mean square, LMS, along with an adaptive observer. The proposed techniques use the battery’s terminal voltage and current to estimate the OCV, which is correlated to the state of charge (SOC. Experimental results highlight the effectiveness of the proposed methods in online estimation at different charge/discharge conditions and temperatures. The comparative study illustrates the advantages and limitations of each online estimation method.

  19. In vivo patch clamp recording technique in the study of neurophysiology

    Institute of Scientific and Technical Information of China (English)

    Lan-Wei CUI; Yu-Rong LI

    2006-01-01

    The patch clamp recording technique in vivois a blind patch clamp recording methods to record the current of the spinal or cereral neurons of anaesthesia ( or awake) animals. This technique can be used to study the synaptic function and plasticity in central nervous system in vivoin order to understand the physiological properties of the ion channels from an integrated point of view. The advantage of this technique have already presented itself in the study of the synaptic transmission and nervous network. Nowadays, in vivo patch whole-cell recording technique in combination with other techniques is becoming a common method in the research fields.

  20. Method and apparatus for controlling LCL converters using asymmetric voltage cancellation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hunter; Sealy, Kylee Devro; Sharp, Bryan Thomas; Gilchrist, Aaron

    2016-01-26

    A method and apparatus for LCL resonant converter control utilizing Asymmetric Voltage Cancellation is described. The methods to determine the optimal trajectory of the control variables are discussed. Practical implementations of sensing load parameters are included. Simple PI, PID and fuzzy logic controllers are included with AVC for achieving good transient response characteristics with output current regulation.

  1. Voltage-guided ablation technique for cavotricuspid isthmus-dependent atrial flutter

    DEFF Research Database (Denmark)

    Jacobsen, Peter K; Klein, George J; Gula, Lorne J

    2012-01-01

    with large amplitude atrial electrograms results in a highly efficient alternate method for the interruption of conduction across the cavotricuspid isthmus. Understanding the bundle structure of conduction over the isthmus facilitates more flexible approaches to its ablation and targeting maximum voltages...

  2. RF transconductor linearization technique robust to process, voltage and temperature variations

    NARCIS (Netherlands)

    Kundur Subramaniyan, Harish; Klumperink, Eric A.M.; Nauta, Bram; Venkatesh, Srinivasan; Kiaei, Ali

    2014-01-01

    A new reconfigurable linearized low noise transconductance amplifier (LNTA) design for a software-defined radio receiver is presented. The transconductor design aims at realizing high linearity at RF in a way that is robust for Process, Voltage and Temperature variations. It exploits resistive degen

  3. A Survey on Voltage Boosting Techniques for Step-Up DC-DC Converters

    DEFF Research Database (Denmark)

    Forouzesh, Mojtaba; Siwakoti, Yam Prasad; Gorji, Saman Asghari;

    2016-01-01

    Step-up dc-dc converters are used to boost the voltage level of the input to a higher output level. Despite of its features such as simplicity of implementation, the fundamental boost dc-dc converter has shortcomings such as low boost ability and low power density. With these limitations, researc...

  4. BiasMDP: Carrier lifetime characterization technique with applied bias voltage

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Paul M., E-mail: paul.jordan@namlab.com; Simon, Daniel K.; Dirnstorfer, Ingo [Nanoelectronic Materials Laboratory gGmbH (NaMLab), Nöthnitzer Straße 64, 01187 Dresden (Germany); Mikolajick, Thomas [Nanoelectronic Materials Laboratory gGmbH (NaMLab), Nöthnitzer Straße 64, 01187 Dresden (Germany); Technische Universität Dresden, Institut für Halbleiter- und Mikrosystemtechnik, 01062 Dresden (Germany)

    2015-02-09

    A characterization method is presented, which determines fixed charge and interface defect densities in passivation layers. This method bases on a bias voltage applied to an electrode on top of the passivation layer. During a voltage sweep, the effective carrier lifetime is measured by means of microwave detected photoconductivity. When the external voltage compensates the electric field of the fixed charges, the lifetime drops to a minimum value. This minimum value correlates to the flat band voltage determined in reference impedance measurements. This correlation is measured on p-type silicon passivated by Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}/HfO{sub 2} stacks with different fixed charge densities and layer thicknesses. Negative fixed charges with densities of 3.8 × 10{sup 12 }cm{sup −2} and 0.7 × 10{sup 12 }cm{sup −2} are determined for Al{sub 2}O{sub 3} layers without and with an ultra-thin HfO{sub 2} interface, respectively. The voltage and illumination dependencies of the effective carrier lifetime are simulated with Shockley Read Hall surface recombination at continuous defects with parabolic capture cross section distributions for electrons and holes. The best match with the measured data is achieved with a very low interface defect density of 1 × 10{sup 10 }eV{sup −1} cm{sup −2} for the Al{sub 2}O{sub 3} sample with HfO{sub 2} interface.

  5. Analysis of bias voltage scan data recorded with hybrid Timepix1 silicon pixel assemblies at the DESY testbeam

    CERN Document Server

    Maimon, Shir

    2014-01-01

    This report will present results from the analysis of bias voltage scans in Timepix1 testbeam data. Three assemblies of varying sensor thickness were used to collect data. The effect of the bias voltage on charge sharing, in particular cluster size, was investigated and found to have a significant impact. The effect of the bias voltage on energy collection was also studied, leading to estimates for the depletion voltage, donor concentration, mobility and resistivity of each assembly. Finally, the effect of the bias voltage on the two-hit cluster resolution and detection efficiency was investigated. This report contains extracts from a longer document (LCD-OPEN-2014-001).

  6. Effect of recording/playback technique and experimental method on assessments of noise

    DEFF Research Database (Denmark)

    Celik, Emine; Persson-Waye, Kerstin; Møller, Henrik

    2008-01-01

    The study investigated possible effects of recording/playback technique and experimental method on assessments of annoyance, loudness and unpleasantness. A possible effect of exposure duration was also studied. Sounds were recorded with two different techniques: monophonic and binaural (dummy......-head technique). In addition, they were reproduced with three different techniques: monophonic recordings presented through a loudspeaker system, binaural recordings presented through closed (circum-aural) and completely open (free-of-the-ear headphones. The study adopted three psychometric methods...... of experiments and interpretation of results. The results also show that long-term annoyance and unpleasantness are poorly predicted by short-duration methods....

  7. PV Power-Generation System with a Phase-Shift PWM Technique for High Step-Up Voltage Applications

    Directory of Open Access Journals (Sweden)

    Cheng-Tao Tsai

    2012-01-01

    Full Text Available A PV power-generation system with a phase-shift pulse-width modulation (PWM technique for high step-up voltage applications is proposed. The proposed power-generation system consists of two stages. In the input stage, all power switches of the full-bridge converter with phase-shift technique can be operated with zero-current switching (ZCS at turn-on or turn-off transition. Hence, the switching losses of the power switches can be reduced. Then, in the DC output stage, a voltage-doubler circuit is used to boost a high dc-link bus voltage. To supply a utility power, a dc/ac inverter is connected to induce a sinusoidal source. In order to draw a maximum power from PV arrays source, a microcontroller is incorporated with the perturbation and observation method to implement maximum power point tracking (MPPT algorithm and power regulating scheme. In this study, a full load power of 300 W prototype has been built. Experimental results are presented to verify the performance and feasibility of the proposed PV power-generation system.

  8. Forward voltage short-pulse technique for measuring high power laser array junction temperature

    Science.gov (United States)

    Meadows, Byron L. (Inventor); Amzajerdian, Frazin (Inventor); Barnes, Bruce W. (Inventor); Baker, Nathaniel R. (Inventor)

    2012-01-01

    The present invention relates to a method of measuring the temperature of the P-N junction within the light-emitting region of a quasi-continuous-wave or pulsed semiconductor laser diode device. A series of relatively short and low current monitor pulses are applied to the laser diode in the period between the main drive current pulses necessary to cause the semiconductor to lase. At the sufficiently low current level of the monitor pulses, the laser diode device does not lase and behaves similar to an electronic diode. The voltage across the laser diode resulting from each of these low current monitor pulses is measured with a high degree of precision. The junction temperature is then determined from the measured junction voltage using their known linear relationship.

  9. FPGA techniques based new hybrid modulation strategies for voltage source inverters.

    Science.gov (United States)

    Sudha, L U; Baskaran, J; Elankurisil, S A

    2015-01-01

    This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switching and carrier based pulse width modulation methods. Thus, the harmonic pollution in the power system will be reduced and the power quality will be augmented with better harmonic profile for a target fundamental output voltage. The proposed modulation strategies are simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor. The feasibility of these modulation strategies is authenticated through simulation and experimental results.

  10. Voltage-guided ablation technique for cavotricuspid isthmus-dependent atrial flutter: refining the continuous line.

    Science.gov (United States)

    Jacobsen, Peter K; Klein, George J; Gula, Lorne J; Krahn, Andrew D; Yee, Raymond; Leong-Sit, Peter; Mechulan, Alexis; Skanes, Allan C

    2012-06-01

    Ablation of the cavotricuspid isthmus has become first-line therapy for "isthmus-dependent" atrial flutter. The goal of ablation is to produce bidirectional cavotricuspid isthmus block. Traditionally, this has been obtained by creation of a complete ablation line across the isthmus from the ventricular end to the inferior vena cava. This article describes an alternative method used in our laboratory. There is substantial evidence that conduction across the isthmus occurs preferentially over discrete separate bundles of tissue. Consequently, voltage-guided ablation targeting only these bundles with large amplitude atrial electrograms results in a highly efficient alternate method for the interruption of conduction across the cavotricuspid isthmus. Understanding the bundle structure of conduction over the isthmus facilitates more flexible approaches to its ablation and targeting maximum voltages in our hands has resulted in reduction of ablation time and fewer recurrences.

  11. FPGA Techniques Based New Hybrid Modulation Strategies for Voltage Source Inverters

    OpenAIRE

    Sudha, L. U.; J. Baskaran; Elankurisil, S. A.

    2015-01-01

    This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switch...

  12. Practical recording techniques the step-by-step approach to professional audio recording

    CERN Document Server

    Bartlett, Bruce

    2013-01-01

    Hands-on practical guide covering all aspects of recording, ideal for beginning and intermediate recording engineers, producers, musicians and audio enthusiasts. Filled with tips and shortcuts, this book offers advice on equipping a home studio (both low-budget and advanced), suggestions for set-up, acoustics, choosing monitor speakers, and preventing hum. This best-selling guide also tells how to judge recordings and improve them to produce maximum results. New material covered in the 5th edition to include: * complete revision and update of dig

  13. A model for mark size dependence on field emission voltage in heat-assisted magnetic probe recording on CoNi/Pt multilayers

    NARCIS (Netherlands)

    Zhang, Li; Bain, James A.; Zhu, Jian-Gang; Abelmann, Leon; Onoue, Takahiro

    2004-01-01

    A method of heat-assisted magnetic recording (HAMR) potentially suitable for probe-based storage systems is characterized. In this work, field emission current from a scanning tunneling microscope (STM) tip is used as the heating source. Pulse voltages of 2-7 V with a duration of 500 ns were applied

  14. Complemenary body driving - a low voltage analog circuit technique for SOI

    Science.gov (United States)

    Mojarradi, M. M.; Terry, S.; Blalock, B. J.; Yong, L.; Dufrene, B.

    2002-01-01

    This paper describes several analog circuit primitives that utilize the body terminal as a signal port. A cascode current mirror that can operate with an input and output voltage of 200 mV; and a rail-to-rail, constant transconductance gain block capable of 1 V operation are presented. These circuits have been implemented in a standard 0.351 partially-depleted Silicon-on-Insulator (PDSOI) CMOS process and should find wide application in next-generation analog circuit designs.

  15. Impact of PLL Parameters Variation on the Pulsating Voltage Injection Technique Based PMSM Position Estimation at Low Speeds

    Directory of Open Access Journals (Sweden)

    Olfa Bel Hadj Brahim Kechiche

    2014-06-01

    Full Text Available This study highlights the impact of an universal Phase Locked Loop (PLL parameters variation on PMSM position estimation at low speeds. Indeed, the PLL parameters variation impact on the PMSM rotor position estimation performance and robustness cannot be neglected anymore. For this purpose, the study presents the theory and simulation results of a demodulation scheme applied to Sensorless PMSM control based on the Pulsating Voltage Injection (PVI technique. Comprehensive simulations, carried out under MATLAB/SIMULINK®, are discussed according to the variation of the PLL proportional and integral parameters.

  16. Differential voltage analyses of high-power, lithium-ion cells. 1. Technique and application

    Science.gov (United States)

    Bloom, Ira; Jansen, Andrew N.; Abraham, Daniel P.; Knuth, Jamie; Jones, Scott A.; Battaglia, Vincent S.; Henriksen, Gary L.

    The C/25 discharge data from 18650-size cells containing LiNi 0.8Co 0.1Al 0.1O 2 cathode and graphite anode laminates were analyzed through the use of the differential voltage, d V/d Q, curves. Using half-cell data, the peaks in the d V/d Q curve of the full cell data were assigned. Analysis of the relative peak shifts allowed for the determination of the source of capacity fade. For cells formed and aged at 45 °C for 40 weeks (capacity fade = 7.5%), the analysis indicated negligible loss of accessible material at the anode and at the cathode. Capacity loss of the cell could be accounted for, largely, by side reactions at the anode. This type of analysis can be used when the introduction of a reference electrode is difficult or impractical.

  17. Holographic theory and recording techniques. Citations from the NTIS data base

    Science.gov (United States)

    Carrigan, B.

    1980-05-01

    The topics cited include holographic recording techniques, theory, equipment, and materials. Among the techniques cited are color holography, X-ray holography, high speed holography, and motion picture holography. Photographic materials, films, emulsions, and equipment for recording and information storage are covered. Techniques for image motion compensation, image deblurring, wave-front reconstruction, and resolution are also cited. This updated bibliography contains 251 abstracts, 17 of which are new entries to the previous edition.

  18. A simplified technique for making an interocclusal record in fixed prosthodontics.

    Science.gov (United States)

    Moghadam, Marjan; Moghadam, Bijan

    2005-01-01

    A technique for using flowable composite resin for making interocclusal records in cases involving fixed prosthodontics is described. The precise relation of maxillary and mandibular casts is an essential step in developing accurate occlusion in fixed prosthodontics. This technique consists of direct intraoral fabrication of transfer copings and an interocclusal record using flowable, light-activated composite resin. The technique is simple, does not require advance preparation and can be done during the final impression appointment.

  19. Modulation Technique for Four-Leg Voltage Source Inverter without a Look-Up Table

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Farhangi, Shahrokh; Iman-Eini, Hossein

    2016-01-01

    , is calculated without need of a look-up table and complex equations. Applying the dead time by software is very straightforward in the proposed technique. In addition, by simplification of the proposed modulation technique, it can be applied to the three-leg inverters. Simulation results in PSCAD...

  20. Robust Sequential Circuits Design Technique for Low Voltage and High Noise Scenarios

    Directory of Open Access Journals (Sweden)

    Garcia-Leyva Lancelot

    2016-01-01

    In this paper we introduce an innovative input and output data redundancy principle for sequential block circuits, the responsible to keep the state of the system, showing its efficiency in front of other robust technique approaches. The methodology is totally different from the Von Neumann approaches, because element are not replicated N times, but instead, they check the coherence of redundant input data no allowing data propagation in case of discrepancy. This mechanism does not require voting devices.

  1. Low-Power Circuit Techniques for Low-Voltage Pipelined ADCs Based on Switched-Opamp Architecture

    Science.gov (United States)

    Ou, Hsin-Hung; Chang, Soon-Jyh; Liu, Bin-Da

    This paper proposes useful circuit structures for achieving a low-voltage/low-power pipelined ADC based on switched-opamp architecture. First, a novel unity-feedback-factor sample-and-hold which manipulates the features of switched-opamp technique is presented. Second, opamp-sharing is merged into switched-opamp structure with a proposed dual-output opamp configuration. A 0.8-V, 9-bit, 10-Msample/s pipelined ADC is designed to verify the proposed circuit. Simulation results using a 0.18-μm CMOS 1P6M process demonstrate the figure-of-merit of this pipelined ADC is only 0.71pJ/step.

  2. Ultra low voltage and low power Static Random Access Memory design using average 6.5T technique

    Directory of Open Access Journals (Sweden)

    Nagalingam RAJESWARAN

    2015-12-01

    Full Text Available Power Stringent Static Random Access Memory (SRAM design is very much essential in embedded systems such as biomedical implants, automotive electronics and energy harvesting devices in which battery life, input power and execution delay are of main concern. With reduced supply voltage, SRAM cell design will go through severe stability issues. In this paper, we present a highly stable average nT SRAM cell for ultra-low power in 125nm technology. The distinct difference between the proposed technique and other conventional methods is about the data independent leakage in the read bit line which is achieved by newly introduced block mask transistors. An average 6.5T SRAM and average 8T SRAM are designed and compared with 6T SRAM, 8T SRAM, 9T SRAM, 10T SRAM and 14T SRAM cells. The result indicates that there is an appreciable decrease in power consumption and delay.

  3. ­The Geospatial Metadata Manager’s Toolbox: Three Techniques for Maintaining Records

    Directory of Open Access Journals (Sweden)

    Bruce Godfrey

    2015-07-01

    Full Text Available Managing geospatial metadata records requires a range of techniques. At the University of Idaho Library, we have tens of thousands of records which need to be maintained as well as the addition of new records which need to be normalized and added to the collections. We show a graphical user interface (GUI tool that was developed to make simple modifications, a simple XSLT that operates on complex metadata, and a Python script with enables parallel processing to make maintenance tasks more efficient. Throughout, we compare these techniques and discuss when they may be useful.

  4. The importance of recording and playback technique for assessment of annoyance

    DEFF Research Database (Denmark)

    Celik, Emine; Persson Waye, Kerstin; Møller, Henrik

    2005-01-01

    and response to sounds, several methods have been adopted both with regard to recording techniques (monophonic or binaural recordings), playback techniques (through headphones or loudspeakers) and subjective evaluation techniques. The present study was carried out to investigate if there is a difference...... in perception related to annoyance, loudness and unpleasantness between monophonic recordings played back through a loudspeaker and binaural recordings played back via headphones and to evaluate whether a possible difference depends on temporal and frequency characteristics as well as spatial characteristics...... of the sound. The experiment also investigates various psychometric methods for achieving responses from subjects, and different durations of the exposure were used. Fifty-four young students participated and three types of stimuli were used in the experiments: road traffic sound, everyday “restaurant” sounds...

  5. Assessment of annoyance, loudness and unpleasantness with different recording and playback techniques

    DEFF Research Database (Denmark)

    Celik, Emine; Persson Waye, Kerstin; Møller, Henrik

    2005-01-01

    of perception and response to sounds, several methods have been adopted both with regard to recording techniques (monophonic or binaural recordings), playback techniques (through headphones or loudspeakers) and subjective evaluation techniques. The present study was carried out to investigate...... if there is a difference in perception related to annoyance, loudness and unpleasantness between monophonic recordings played back through a loudspeaker and binaural recordings played back via headphones and to evaluate whether a possible difference depends on temporal and frequency characteristics as well as spatial...... characteristics of the sound. The experiment also investigates various psychometric methods for achieving responses from subjects, and different durations of the exposure were used. Fifty-four young students participated and three types of stimuli were used in the experiments: road traffic sound, everyday...

  6. Data processing of high-rate low-voltage distribution grid recordings for smart grid monitoring and analysis

    Science.gov (United States)

    Maaß, Heiko; Cakmak, Hüseyin Kemal; Bach, Felix; Mikut, Ralf; Harrabi, Aymen; Süß, Wolfgang; Jakob, Wilfried; Stucky, Karl-Uwe; Kühnapfel, Uwe G.; Hagenmeyer, Veit

    2015-12-01

    Power networks will change from a rigid hierarchic architecture to dynamic interconnected smart grids. In traditional power grids, the frequency is the controlled quantity to maintain supply and load power balance. Thereby, high rotating mass inertia ensures for stability. In the future, system stability will have to rely more on real-time measurements and sophisticated control, especially when integrating fluctuating renewable power sources or high-load consumers like electrical vehicles to the low-voltage distribution grid.

  7. Version based spatial record management techniques for spatial database management system

    Institute of Scientific and Technical Information of China (English)

    KIM Ho-seok; KIM Hee-taek; KIM Myung-keun; BAE Hae-young

    2004-01-01

    The search operation of spatial data was a principal operation in existent spatial database management system, but the update operation of spatial data such as tracking are occurring frequently in the spatial database management system recently. So, necessity of concurrency improvement among transactions is increasing. In general database management system, many techniques have been studied to solve concurrency problem of transaction. Among them, multi-version algorithm does to minimize interference among transactions. However, to apply existent multi-version algorithm to improve concurrency of transaction to spatial database management system, the waste of storage happens because it must store entire version for spatial record even if only aspatial data of spatial record is changed. This paper has proposed the record management techniques to manage separating aspatial data version and spatial data version to decrease waste of storage for record version and improve concurrency among transactions.

  8. Evaluation of a fiber-optic technique for recording intramuscular pressure in the human leg.

    Science.gov (United States)

    Nilsson, Andreas; Zhang, Qiuxia; Styf, Jorma

    2016-10-01

    To evaluate a forward-sensing fiber-optic pressure technique for recording of intramuscular pressure (IMP) in the human leg and investigate factors that may influence IMP measurements used in diagnosing compartment syndromes. IMP in the tibialis anterior muscle was recorded simultaneously by a fiber-optic technique and needle-injection technique in 12 legs of 7 healthy subjects. Both measurement catheters were placed in parallel with the muscle fibers to the same depth, as verified by sonography. IMP recordings were performed at rest before, during and after applying a model of abnormally elevated IMP (simulated compartment syndrome). IMP was elevated by venous obstruction induced by a thigh tourniquet of a casted leg. IMP was also measured during injections of 0.1 ml of saline into the muscle through the catheters. IMP at baseline was 5.1 (SD = 2.6) mmHg measured with the fiber-optic technique and 7.1 (SD = 2.5) mmHg with the needle-injection technique (p syndrome. IMP increased significantly following injection of 0.1 ml of saline, measured by both techniques. It remained increased 1 min after injection. The fiber-optic technique was able to record pulse-synchronous IMP oscillations. The fiber-optic technique may be used for IMP measurements in a muscle with both normal and abnormally elevated IMP. It has good dynamic properties allowing for measurement of IMP oscillations. Saline injection used with needle-injection systems to ensure catheter patency compromises IMP readings at least one minute after injection.

  9. A Low-Voltage Ride-Through Technique for Grid-Connected Converters with Reduced Power Transistors Stress

    DEFF Research Database (Denmark)

    Chen, Hsin-Chih; Lee, Chia-Tse; Cheng, Po-Tai

    2016-01-01

    With more and more distributed energy resources being installed in the utility grid, grid operators start imposing the low-voltage ride-through requirement on such systems to remain grid-connected and inject reactive and/or active current to support grid voltage during fault conditions. This pape...

  10. Using text-mining techniques in electronic patient records to identify ADRs from medicine use

    DEFF Research Database (Denmark)

    Warrer, Pernille; Hansen, Ebba Holme; Jensen, Lars Juhl

    2012-01-01

    This literature review included studies that use text-mining techniques in narrative documents stored in electronic patient records (EPRs) to investigate ADRs. We searched PubMed, Embase, Web of Science and International Pharmaceutical Abstracts without restrictions from origin until July 2011. W...

  11. Temporomandibular joint sounds: a critique of techniques for recording and analysis.

    Science.gov (United States)

    Widmer, C G

    1989-01-01

    Sonography, or the graphic recording of sounds, has been proposed as an objective measure of various pathological conditions in the temporomandibular joint. Various electronic devices have been developed to enhance our ability to auscultate the joint, monitor the timing of the sounds with jaw movement, and analyze the characteristics of the sound; the intent of these devices is to diagnose the intracapsular condition "objectively." This review paper critically evaluates the advantages and limitations of this technique. Based on the existing literature, these instruments can record sounds; however, the origin of these sounds is uncertain, since room noise, skin and hair sounds, respiration, arterial blood flow, and cross-over noises from the opposite TMJ have not been excluded as possible artifacts of the recording. More important, the diagnostic specificity, as an indicator of each type of TMJ disease, has not been clearly and consistently demonstrated with the sonographic technique.

  12. Comparative Analysis of Different PWM Techniques to Reduce the Common Mode Voltage in Three-Level Neutral-Point-Clamped Inverters for Variable Speed Induction Drives

    Directory of Open Access Journals (Sweden)

    Bharati Raja

    2012-12-01

    Full Text Available This work presents the comparative study of the different PWM techniques to reduce the common-mode voltage (CMV at the output of neutral point diode clamped inverter for variable speed drives. Here the comparative study is done by the phase opposition disposed (POD, sinusoidal pulse width modulation (SPWM, phase disposition (PD, phase shift (PS space vector modulation (SVM techniques are proposed. A good trade-off between the quality of the output voltage and the partial magnitude of the CMV is achieved in this work. The scheme is proposed for three-level inverter. This work realizes the implementation of Three-level diode clamped MLI for three-phase (Y-Δ induction motor with the implementation of a space vector modulation technique without any additional control algorithm to reduce CMV within the range + Vdc/6. The Simulation with a 1HP induction motor drive system is setup in Matlab-2011b  and the same results validated effectively by hardware – FPGA-SPARTEN III processor and its shows that the CM voltage is effectively reduced and the maximum output voltage is not affected.  

  13. A voltage-dependent persistent sodium current in mammalian hippocampal neurons

    OpenAIRE

    1990-01-01

    Currents generated by depolarizing voltage pulses were recorded in neurons from the pyramidal cell layer of the CA1 region of rat or guinea pig hippocampus with single electrode voltage-clamp or tight- seal whole-cell voltage-clamp techniques. In neurons in situ in slices, and in dissociated neurons, subtraction of currents generated by identical depolarizing voltage pulses before and after exposure to tetrodotoxin revealed a small, persistent current after the transient current. These curren...

  14. Predictable Technique to Register Retruded Contact Position (RCP) Using a Disposable Jaw Relation Recording Device.

    Science.gov (United States)

    Daher, Tony; Lobel, William A; Massad, Joseph; Ahuja, Swati; Danilov, Zarko Jack

    2015-05-01

    The dental literature presents various definitions and techniques to describe and register centric relation (CR) or centric occlusion (CO). Briefly reviewing the literature in relation to CR, this article proposes the use of the term retruded contact position (RCP), clinically defined as retruded, unstrained, repeatable position and where the mandibular movements start when a Gothic arch tracing is used. With this clinical definition, a technique can be easily selected that meets all the requirements of such position. The article discusses the use of a jaw recorder that is an intraorally graphic recording device that results in a tracing of mandibular movements in one plane, with the apex of the tracing indicating the retruded, unstrained, and repeatable relationship. The intersection of the arcs produced by the right and left working movement form the apex of the Gothic arch tracing. Several clinical situations using the jaw recorder are described. Clinicians can now quickly and accurately record RCP, balance complete, partial, or implant dentures, and orthopedically reposition the mandible. The technique achieves highly reliable and reproducible results.

  15. Book review of Electrophysiological Recording Techniques, edited by Robert P Vertes and Robert W Stackman, Jr

    Directory of Open Access Journals (Sweden)

    Kolev Vasil

    2011-07-01

    Full Text Available Abstract The review presents the newly published book "Electrophysiological Recording Techniques" by Humana Press. This is an important collection of articles devoted to an issue that has gained increasing attention in modern neuroscience research - electrophysiological recording techniques. The present book is a timely update of methods spanning from single cell recordings to local field potentials, cortical, and scalp EEG recordings. The book presents the progressive development of electrophysiological recording methods by including both existing and new advanced technologies. Theoretical considerations on important issues like current source density analysis, local field potential and signal generation are also in focus. In most of the chapters, methods are illustrated with specific experimental results and are discussed towards future developments and applications. Chapters can be read independently because each chapter appears with its own theoretical background, literature survey and specific methodology. The book can be of interest to a broader audience willing to look at the contemporary state of development of electrophysiological methods. Also, it can be of special interest to scientists with high expertise working in the field of neuroscience and behavior.

  16. Maximum voltage gradient technique for optimization of ablation for typical atrial flutter with zero-fluoroscopy approach.

    Science.gov (United States)

    Deutsch, Karol; Śledź, Janusz; Mazij, Mariusz; Ludwik, Bartosz; Labus, Michał; Karbarz, Dariusz; Pasicka, Bernadetta; Chrabąszcz, Michał; Śledź, Arkadiusz; Klank-Szafran, Monika; Vitali-Sendoz, Laura; Kameczura, Tomasz; Śpikowski, Jerzy; Stec, Piotr; Ujda, Marek; Stec, Sebastian

    2017-06-01

    Radiofrequency catheter ablation (RFCA) is an established effective method for the treatment of typical cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL). The introduction of 3-dimensional electro-anatomic systems enables RFCA without fluoroscopy (No-X-Ray [NXR]). The aim of this study was to evaluate the feasibility and effectiveness of CTI RFCA during implementation of the NXR approach and the maximum voltage-guided (MVG) technique for ablation of AFL.Data were obtained from prospective standardized multicenter ablation registry. Consecutive patients with the first RFCA for CTI-dependent AFL were recruited. Two navigation approaches (NXR and fluoroscopy based as low as reasonable achievable [ALARA]) and 2 mapping and ablation techniques (MVG and pull-back technique [PBT]) were assessed. NXR + MVG (n  =  164; age: 63.7 ± 9.5; 30% women), NXR + PBT (n  =  55; age: 63.9 ± 10.7; 39% women); ALARA + MVG (n  =  36; age: 64.2 ± 9.6; 39% women); and ALARA + PBT (n  =  205; age: 64.7 ± 9.1; 30% women) were compared, respectively. All groups were simplified with a 2-catheter femoral approach using 8-mm gold tip catheters (Osypka AG, Germany or Biotronik, Germany) with 15 min of observation. The MVG technique was performed using step-by-step application by mapping the largest atrial signals within the CTI.Bidirectional block in CTI was achieved in 99% of all patients (P  =  NS, between groups). In NXR + MVG and NXR + PBT groups, the procedure time decreased (45.4 ± 17.6 and 47.2 ± 15.7 min vs. 52.6 ± 23.7 and 59.8 ± 24.0 min, P < .01) as compared to ALARA + MVG and ALARA + PBT subgroups. In NXR + MVG and NXR + PBT groups, 91% and 98% of the procedures were performed with complete elimination of fluoroscopy. The NXR approach was associated with a significant reduction in fluoroscopy exposure (from 0.2 ± 1.1 [NXR + PBT] and 0.3 ± 1.6 [NXR + MVG] to 7.7 ± 6.0 min [ALARA + MVG] and 9

  17. Design techniques and analysis of high-resolution neural recording systems targeting epilepsy focus localization.

    Science.gov (United States)

    Shoaran, Mahsa; Pollo, Claudio; Leblebici, Yusuf; Schmid, Alexandre

    2012-01-01

    The design of a high-density neural recording system targeting epilepsy monitoring is presented. Circuit challenges and techniques are discussed to optimize the amplifier topology and the included OTA. A new platform supporting active recording devices targeting wireless and high-resolution focus localization in epilepsy diagnosis is also proposed. The post-layout simulation results of an amplifier dedicated to this application are presented. The amplifier is designed in a UMC 0.18µm CMOS technology, has an NEF of 2.19 and occupies a silicon area of 0.038 mm(2), while consuming 5.8 µW from a 1.8-V supply.

  18. Applying Time-sharing technique in a multimodal compact low-power CMOS neurochip for simultaneous neurochemical and action potential recording.

    Science.gov (United States)

    Poustinchi, Mohammad; Stacey, R Greg; Musallam, Sam

    2014-01-01

    Brain is an electrochemical system and recent studies suggest simultaneous measurement of interrelated brain's electrical and neurochemical activity may lead to better understanding of brain function in addition to developing optimal neural prosthetics. By exploiting opamp Time-sharing technique to minimized power dissipation and silicon area, we have fabricated a power efficient implantable CMOS microsystem for simultaneous measurement of Action Potential (AP) and neurotransmitter concentration. Both AP-recording and neurotransmitter sensing subsystems share a single 653 nW amplifier which senses picoscale to microscale current that corresponds to micromolar neurotransmitter concentration and microscale AP voltage. This microsystem is fabricated in CMOS 0.18 μm technology and tested using recorded signals from dorsal premotor cortex (PMd) area of a macaque monkey in our lab.

  19. Voltage sags and transient detection and classification using half/one-cycle windowing techniques based on continuous s-transform with neural network

    Science.gov (United States)

    Daud, Kamarulazhar; Abidin, Ahmad Farid; Ismail, Ahmad Puad

    2017-08-01

    This paper was conducted to detect and classify the different power quality disturbance (PQD) using Half and One-Cycle Windowing Technique (WT) based on Continuous S-Transform (CST) and Neural Network (NN). The system using 14 bus bars based on IEEE standard had been designing using MATLAB©/Simulink to provide PQD data. The datum of PQD is analyzed by using WT based on CST to extract features and it characteristics. Besides, the study focused an important issue concerning the identification of PQD selection and detection, the feature and characteristics of two types of signals such as voltage sag and transient signal are obtained. After the feature extraction, the classified process had been done using NN to show the percentage of classification PQD either voltage sags or transients. The analysis show which selection of cycle for windowing technique can provide the smooth detection of PQD and the suitable characteristic to provide the highest percentage of classification of PQD.

  20. Characterization of Highly Efficient CdTe Thin Film Solar Cells by the Capacitance-Voltage Profiling Technique

    Science.gov (United States)

    Okamoto, Tamotsu; Yamada, Akira; Konagai, Makoto

    2000-05-01

    The electrical properties of highly efficient CdTe thin film solar cells prepared by close-spaced sublimation (CSS) were investigated by capacitance-voltage (C-V) measurement. According to the dependence of the cell performance on the substrate temperature in the CSS process, the open-circuit voltage (Voc) increased with increasing the substrate temperature below 630°C@. The carrier concentration profiles revealed that the net acceptor concentration exponentially increased from the CdS/CdTe interface to the rear and that the acceptor concentration increased with increasing substrate temperature. This result suggests that Voc is improved as a result of the increase in the acceptor concentration.

  1. Mixed voltage VLSI design

    Science.gov (United States)

    Panwar, Ramesh; Rennels, David; Alkalaj, Leon

    1993-01-01

    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.

  2. Recording the trigemino-facial inhibitory reflex: technique and normal findings.

    Science.gov (United States)

    Cattaneo, Luigi; Pavesi, Giovanni

    2010-04-01

    The aim of this study was to propose a standardized technique for recording the trigemino-facial inhibitory reflex (TFIR) and to provide reference data of its components. The TFIR was recorded with concentric needle electrodes from the voluntarily activated depressor anguli oris muscle bilaterally in 26 healthy subjects (23-83 years). A vertical line was drawn from the corner of the mouth to the mandible margin, from which the needle insertion point was localized moving 1 to 2 cm upward and 1 to 2 cm laterally. The mentalis nerve was stimulated by surface electrodes at an intensity of 10x the perceptive threshold. The recovery cycle was studied at interstimulus intervals of 200, 350, and 500 milliseconds. The TFIR was constantly elicited in all participants. Upper normal limits (mean +/- 3 SD) of latency of the TFIR both ipsilateral and contralateral to stimulation were 65 milliseconds. Recovery of the reflex was of 71% at 200 milliseconds, 84% at 350 milliseconds, and 98% at 500 milliseconds interstimulus intervals. The recovery at the 200 milliseconds interstimulus intervals increased significantly with participant's age. The TFIR can be consistently and reliably recorded from the depressor anguli oris muscle using a standard technique. The reflex is robust showing complete recovery at 500 milliseconds interstimulus intervals.

  3. Study on key techniques for camera-based hydrological record image digitization

    Science.gov (United States)

    Li, Shijin; Zhan, Di; Hu, Jinlong; Gao, Xiangtao; Bo, Ping

    2015-10-01

    With the development of information technology, the digitization of scientific or engineering drawings has received more and more attention. In hydrology, meteorology, medicine and mining industry, the grid drawing sheet is commonly used to record the observations from sensors. However, these paper drawings may be destroyed and contaminated due to improper preservation or overuse. Further, it will be a heavy workload and prone to error if these data are manually transcripted into the computer. Hence, in order to digitize these drawings, establishing the corresponding data base will ensure the integrity of data and provide invaluable information for further research. This paper presents an automatic system for hydrological record image digitization, which consists of three key techniques, i.e., image segmentation, intersection point localization and distortion rectification. First, a novel approach to the binarization of the curves and grids in the water level sheet image has been proposed, which is based on the fusion of gradient and color information adaptively. Second, a fast search strategy for cross point location is invented and point-by-point processing is thus avoided, with the help of grid distribution information. And finally, we put forward a local rectification method through analyzing the central portions of the image and utilizing the domain knowledge of hydrology. The processing speed is accelerated, while the accuracy is still satisfying. Experiments on several real water level records show that our proposed techniques are effective and capable of recovering the hydrological observations accurately.

  4. Voltage stability evaluation facing small disturbances by means of the modal analysis technique; Evaluacion de la estabilidad de voltaje ante disturbios pequenos mediante la tecnica de analisis modal

    Energy Technology Data Exchange (ETDEWEB)

    Leon Rodriguez, Daniel

    2000-12-15

    The economic development of the countries has taken implicit a growing industrialization the one which, joined to those every time bigger resident's necessities, it has caused a constant and progressive increment in the electric power demand. However, in the last years the growth of the electric network of these systems has been more and more limited for diverse such factors as the ecology and the economy, as well as for the social and political costs that implies each new construction in the system. With the presence of these restrictions the electric systems in many cases, have been forced to satisfy the increments in the demand making a more exhaustive use of the infrastructure that they have available and the incorporation of only a few new system elements or constructions. These aspects have caused such systems to operate with more limited security margins and that their stability has to be analyzed in a reliable and precise way. Taking into account the previously mentioned aspects, as the electric systems have had the necessity of operating under forced conditions to satisfy the load demand, voltage stability problems have been presented with more frequency causing serious disturbances and in some cases, total blackouts. With these problems, the voltage stability analysis has taken bigger importance in the studies that the electric utilities carry out. This issue has caused that bigger resources are dedicated for the investigation of this phenomenon with the purpose of understanding and developing tools that allow studying it in a more complete and more truthful way. Modal analysis is one of the most recent and popular steady techniques the one that, from its appearance has had a great peak due to the valuable and quick information that provides, besides its implementation easiness and the little effort computational that it requires. In this work is carried out the voltage stability evaluation of a real electric system applying in a combined way the

  5. Using text-mining techniques in electronic patient records to identify ADRs from medicine use.

    Science.gov (United States)

    Warrer, Pernille; Hansen, Ebba Holme; Juhl-Jensen, Lars; Aagaard, Lise

    2012-05-01

    This literature review included studies that use text-mining techniques in narrative documents stored in electronic patient records (EPRs) to investigate ADRs. We searched PubMed, Embase, Web of Science and International Pharmaceutical Abstracts without restrictions from origin until July 2011. We included empirically based studies on text mining of electronic patient records (EPRs) that focused on detecting ADRs, excluding those that investigated adverse events not related to medicine use. We extracted information on study populations, EPR data sources, frequencies and types of the identified ADRs, medicines associated with ADRs, text-mining algorithms used and their performance. Seven studies, all from the United States, were eligible for inclusion in the review. Studies were published from 2001, the majority between 2009 and 2010. Text-mining techniques varied over time from simple free text searching of outpatient visit notes and inpatient discharge summaries to more advanced techniques involving natural language processing (NLP) of inpatient discharge summaries. Performance appeared to increase with the use of NLP, although many ADRs were still missed. Due to differences in study design and populations, various types of ADRs were identified and thus we could not make comparisons across studies. The review underscores the feasibility and potential of text mining to investigate narrative documents in EPRs for ADRs. However, more empirical studies are needed to evaluate whether text mining of EPRs can be used systematically to collect new information about ADRs.

  6. A Survey of Non-conventional Techniques for Low-voltage Low-power Analog Circuit Design

    National Research Council Canada - National Science Library

    F. Khateb; S. Bay Abo Dabbous; S. Vlassis

    2013-01-01

    ...). Therefore, this paper presents the operation principle, the advantages and disadvantages of each of these techniques, enabling circuit designers to choose the proper design technique based on application...

  7. Recording of natural head position using stereophotogrammetry: a new technique and reliability study.

    Science.gov (United States)

    Hsung, Tai-Chiu; Lo, John; Li, Tik-Shun; Cheung, Lim-Kwong

    2014-11-01

    The purpose of this study was to develop a technique to record physical references and orient digital mesh models to a natural head position using stereophotogrammetry (SP). The first step was to record the digital mesh model of a hanging reference board placed at the capturing position of the SP machine. The board was aligned to true vertical using a plumb bob. It also was aligned with a laser plane parallel to a hanging mirror, which was located at the center of the machine. The parameter derived from the digital mesh model of the board was used to adjust the roll, pitch, and yaw of the subsequent captures of patients' facial images. This information was valid until the next machine calibration. The board placement was repeatable, with standard deviations less than 0.1° for pitch and yaw angles and 0.15° for roll angles.

  8. Influence of bias voltage on the optical and structural properties of nc-Si:H films grown by layer-by-layer (LBL) deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Goh Boon, E-mail: boontong77@yahoo.co [Solid State Research Laboratory, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Gani, Siti Meriam Ab.; Muhamad, Muhamad Rasat; Rahman, Saadah Abdul [Solid State Research Laboratory, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2009-07-01

    The effects of applying a positive bias of 25 to 100 V on the optical, structural and photoluminescence (PL) properties of hydrogenated nanocrystalline silicon (nc-Si:H) films produced by layer-by-layer (LBL) deposition technique has been studied. Optical characterization of the films has been obtained from UV-VIS-NIR spectroscopy measurements. Structural characterization has been performed using X-ray diffraction, micro-Raman spectroscopy and field emission scanning electron microscope (FESEM). PL spectroscopy technique has been used to investigate the PL properties of the films. In general, the films formed shows a mixed phase of silicon (Si) nanocrystallites embedded within an amorphous phase of the Si matrix. The crystalline volume fraction and grain size of the Si nanocrystallites have been shown to be strongly dependent on the applied bias voltage. High applied bias voltage enhances the growth rate of the films but reduces the refractive index and the optical energy gap of the films. Higher crystalline volume fraction of the films prepared at low bias voltages exhibits room temperature PL at around 1.8 eV (700 nm).

  9. Microstructure Investigation of 13Cr-2Mo ODS Steel Components Obtained by High Voltage Electric Discharge Compaction Technique

    Directory of Open Access Journals (Sweden)

    Igor Bogachev

    2015-11-01

    Full Text Available Refractory oxide dispersion strengthened 13Cr-2Mo steel powder was successfully consolidated to near theoretical density using high voltage electric discharge compaction. Cylindrical samples with relative density from 90% to 97% and dimensions of 10 mm in diameter and 10–15 mm in height were obtained. Consolidation conditions such as pressure and voltage were varied in some ranges to determine the optimal compaction regime. Three different concentrations of yttria were used to identify its effect on the properties of the samples. It is shown that the utilized ultra-rapid consolidation process in combination with high transmitted energy allows obtaining high density compacts, retaining the initial structure with minimal grain growth. The experimental results indicate some heterogeneity of the structure which may occur in the external layers of the tested samples due to various thermal and electromagnetic in-processing effects. The choice of the optimal parameters of the consolidation enables obtaining samples of acceptable quality.

  10. A Novel Technique for Fetal ECG Extraction Using Single-Channel Abdominal Recording

    Directory of Open Access Journals (Sweden)

    Nannan Zhang

    2017-02-01

    Full Text Available Non-invasive fetal electrocardiograms (FECGs are an alternative method to standard means of fetal monitoring which permit long-term continual monitoring. However, in abdominal recording, the FECG amplitude is weak in the temporal domain and overlaps with the maternal electrocardiogram (MECG in the spectral domain. Research in the area of non-invasive separations of FECG from abdominal electrocardiograms (AECGs is in its infancy and several studies are currently focusing on this area. An adaptive noise canceller (ANC is commonly used for cancelling interference in cases where the reference signal only correlates with an interference signal, and not with a signal of interest. However, results from some existing studies suggest that propagation of electrocardiogram (ECG signals from the maternal heart to the abdomen is nonlinear, hence the adaptive filter approach may fail if the thoracic and abdominal MECG lack strict waveform similarity. In this study, singular value decomposition (SVD and smooth window (SW techniques are combined to build a reference signal in an ANC. This is to avoid the limitation that thoracic MECGs recorded separately must be similar to abdominal MECGs in waveform. Validation of the proposed method with r01 and r07 signals from a public dataset, and a self-recorded private dataset showed that the proposed method achieved F1 scores of 99.61%, 99.28% and 98.58%, respectively for the detection of fetal QRS. Compared with four other single-channel methods, the proposed method also achieved higher accuracy values of 99.22%, 98.57% and 97.21%, respectively. The findings from this study suggest that the proposed method could potentially aid accurate extraction of FECG from MECG recordings in both clinical and commercial applications.

  11. A Novel Technique for Fetal ECG Extraction Using Single-Channel Abdominal Recording

    Science.gov (United States)

    Zhang, Nannan; Zhang, Jinyong; Li, Hui; Mumini, Omisore Olatunji; Samuel, Oluwarotimi Williams; Ivanov, Kamen; Wang, Lei

    2017-01-01

    Non-invasive fetal electrocardiograms (FECGs) are an alternative method to standard means of fetal monitoring which permit long-term continual monitoring. However, in abdominal recording, the FECG amplitude is weak in the temporal domain and overlaps with the maternal electrocardiogram (MECG) in the spectral domain. Research in the area of non-invasive separations of FECG from abdominal electrocardiograms (AECGs) is in its infancy and several studies are currently focusing on this area. An adaptive noise canceller (ANC) is commonly used for cancelling interference in cases where the reference signal only correlates with an interference signal, and not with a signal of interest. However, results from some existing studies suggest that propagation of electrocardiogram (ECG) signals from the maternal heart to the abdomen is nonlinear, hence the adaptive filter approach may fail if the thoracic and abdominal MECG lack strict waveform similarity. In this study, singular value decomposition (SVD) and smooth window (SW) techniques are combined to build a reference signal in an ANC. This is to avoid the limitation that thoracic MECGs recorded separately must be similar to abdominal MECGs in waveform. Validation of the proposed method with r01 and r07 signals from a public dataset, and a self-recorded private dataset showed that the proposed method achieved F1 scores of 99.61%, 99.28% and 98.58%, respectively for the detection of fetal QRS. Compared with four other single-channel methods, the proposed method also achieved higher accuracy values of 99.22%, 98.57% and 97.21%, respectively. The findings from this study suggest that the proposed method could potentially aid accurate extraction of FECG from MECG recordings in both clinical and commercial applications. PMID:28245585

  12. Application of voltage oriented control technique in a fully renewable, wind powered, autonomous system with storage capabilities

    Science.gov (United States)

    Kondylis, Georgios P.; Vokas, Georgios A.; Anastasiadis, Anestis G.; Konstantinopoulos, Stavros A.

    2017-02-01

    The main purpose of this paper is to examine the technological feasibility of a small autonomous network, with electricity storage capability, which is completely electrified by wind energy. The excess energy produced, with respect to the load requirements, is sent to the batteries for storage. When the energy produced by the wind generator is not sufficient, load's energy requirement is covered by the battery system, ensuring, however, that voltage, frequency and other system characteristics are within the proper boundaries. For the purpose of this study, a Voltage Oriented Control system has been developed in order to monitor the autonomous operation and perform the energy management of the network. This system manages the power flows between the load and the storage system by properly controlling the Pulse Width Modulation pulses in the converter, thus ensuring power flows are adequate and frequency remains under control. The experimental results clearly indicate that a stand-alone wind energy system based on battery energy storage system is feasible and reliable. This paves the way for fully renewable and zero emission energy schemes.

  13. Technological Aspects: High Voltage

    CERN Document Server

    Faircloth, D C

    2013-01-01

    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.

  14. A new technique for fractal analysis applied to human, intracerebrally recorded, ictal electroencephalographic signals.

    Science.gov (United States)

    Bullmore, E; Brammer, M; Alarcon, G; Binnie, C

    1992-11-09

    Application of a new method of fractal analysis to human, intracerebrally recorded, ictal electroencephalographic (EEG) signals is reported. 'Frameshift-Richardson' (FR) analysis involves estimation of fractal dimension (1 EEG data; it is suggested that this technique offers significant operational advantages over use of algorithms for FD estimation requiring preliminary reconstruction of EEG data in phase space. FR analysis was found to reduce substantially the volume of EEG data, without loss of diagnostically important information concerning onset, propagation and evolution of ictal EEG discharges. Arrhythmic EEG events were correlated with relatively increased FD; rhythmic EEG events with relatively decreased FD. It is proposed that development of this method may lead to: (i) enhanced definition and localisation of initial ictal changes in the EEG presumed due to multi-unit activity; and (ii) synoptic visualisation of long periods of EEG data.

  15. A technique to stabilize record bases for Gothic arch tracings in patients with implant-retained complete dentures.

    Science.gov (United States)

    Raigrodski, A J; Sadan, A; Carruth, P L

    1998-12-01

    Clinicians have long expressed concern about the accuracy of the Gothic arch tracing for recording centric relation in edentulous patients. With the use of dental implants to assist in retaining complete dentures, the problem of inaccurate recordings, made for patients without natural teeth, can be significantly reduced. This article presents a technique that uses healing abutments to stabilize the record bases so that an accurate Gothic arch tracing can be made.

  16. Evaluation results on the effectiveness of the corrosion protection system for underground pipelines, using the DC-voltage gradient technique

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Antonio Carlos [Petroquimica Uniao S.A., Santo Andre, SP (Brazil)

    2003-07-01

    A pipeline of diameter 6'' with 17.694 km of extension was evaluated how much to the integrity of its external covering and the effectiveness of the system of cathodic protection, using the method DC-Voltage Gradient. The Cathodic Protection in this pipeline is made by seven rectifiers. The gotten data indicate that the potential pipe-ground registered in some check points to the long one of the pipeline is extremely negative, what has led to a super protection of the pipeline for the CP. This if explains for the great proximity between the anodes and the pipeline. For km had been identified 917 failures with a mean density of 50,1 per Km. Beyond the analysis of the data, this work includes conclusions and recommendations detailed for the repairs of the covering of the pipeline and for improvement of the effectiveness of the CP. One sends regards to a combination of repairs in the covering and reevaluation of the CP, in way to improve the protection level and to assure the reduction of the risk of external corrosion. (author)

  17. Voltage Controlled Dynamic Demand Response

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    . 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...

  18. Low concentration contrast medium for dual-source computed tomography coronary angiography by a combination of iterative reconstruction and low-tube-voltage technique: Feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Minwen, E-mail: zhengmw2007@163.com; Liu, Ying, E-mail: yingyinglyly@126.com; Wei, Mengqi, E-mail: weimengqi2008@163.com; Wu, Yongjie, E-mail: wu18291988526@163.com; Zhao, Hongliang, E-mail: zhaohl1980@163.com; Li, Jian, E-mail: xjyylj@yeah.net

    2014-02-15

    Objectives: To assess the impact of low-concentration contrast medium on vascular enhancement, image quality and radiation dose of coronary CT angiography (cCTA) by using a combination of iterative reconstruction (IR) and low-tube-voltage technique. Materials and methods: One hundred patients were prospectively randomized to two types of contrast medium and underwent prospective electrocardiogram-triggering cCTA (Definition Flash, Siemens Healthcare; collimation: 128 mm × 0.6 mm; tube current: 300 mA s). Fifty patients received Iopromide 370 were scanned using the conventional tube setting (100 kVp or 120 kVp if BMI ≥ 25 kg/m{sup 2}) and reconstructed with filtered back projection (FBP). Fifty patients received Iodixanol 270 were scanned using the low-tube-voltage (80 kVp or 100 kVp if BMI ≥ 25 kg/m{sup 2}) technique and reconstructed with IR. CT attenuation was measured in coronary artery and other anatomical regions. Noise, image quality and radiation dose were compared. Results: Compared with two Iopromide 370 subgroups, Iomeprol 270 subgroups showed no significant difference in CT attenuation (576.63 ± 95.50 vs. 569.51 ± 118.93 for BMI < 25 kg/m{sup 2}, p = 0.647 and 394.19 ± 68.09 vs. 383.72 ± 63.11 for BMI ≥ 25 kg/m{sup 2}, p = 0.212), noise (in various anatomical regions of interest) and image quality (3.5 vs. 4.0, p = 0.13), but significantly (0.41 ± 0.17 vs. 0.94 ± 0.45 for BMI < 25 kg/m{sup 2}, p < 0.001 and 1.14 ± 0.24 vs. 2.37 ± 0.69 for BMI ≥ 25 kg/m{sup 2}, p < 0.001) lower radiation dose, which reflects dose saving of 56.4% and 51.9%, respectively. Conclusions: Combined IR with low-tube-voltage technique, a low-concentration contrast medium of 270 mg I/ml can still maintain the contrast enhancement without impairing image quality, as well as significantly lower the radiation dose.

  19. Critical current density and ac harmonic voltage generation in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} thin films by the screening technique

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Lopez, Israel O., E-mail: iperez@mda.cinvestav.m [Applied Physics Department, Cinvestav Unidad Merida, Km 6 Ant., Carretera a Progreso, A.P. 73, C.P. 97310 Merida, Yucatan (Mexico); Gamboa, Fidel; Sosa, Victor [Applied Physics Department, Cinvestav Unidad Merida, Km 6 Ant., Carretera a Progreso, A.P. 73, C.P. 97310 Merida, Yucatan (Mexico)

    2010-12-15

    The temperature and field dependence of harmonics in voltage V{sub n}=V{sub n}{sup '}-iV{sub n}{sup ''} using the screening technique have been measured for YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconducting thin films. Using the Sun model we obtained the curves for the temperature-dependent critical current density J{sub c}(T). In addition, we applied the criterion proposed by Acosta et al. to compute J{sub c}(T). Also, we made used of the empirical law J{sub c{proportional_to}}(1-T/T{sub c}){sup n} as an input in our calculations to reproduce experimental harmonic generation up to the fifth harmonic. We found that most models fit well the fundamental voltage but higher harmonics are poorly reproduced. Such behavior suggests the idea that higher harmonics contain information concerning complex processes like flux creep or thermally assisted flux flow.

  20. Towards the assimilation of tree-ring-width records using ensemble Kalman filtering techniques

    Science.gov (United States)

    Acevedo, Walter; Reich, Sebastian; Cubasch, Ulrich

    2016-03-01

    This paper investigates the applicability of the Vaganov-Shashkin-Lite (VSL) forward model for tree-ring-width chronologies as observation operator within a proxy data assimilation (DA) setting. Based on the principle of limiting factors, VSL combines temperature and moisture time series in a nonlinear fashion to obtain simulated TRW chronologies. When used as observation operator, this modelling approach implies three compounding, challenging features: (1) time averaging, (2) "switching recording" of 2 variables and (3) bounded response windows leading to "thresholded response". We generate pseudo-TRW observations from a chaotic 2-scale dynamical system, used as a cartoon of the atmosphere-land system, and attempt to assimilate them via ensemble Kalman filtering techniques. Results within our simplified setting reveal that VSL's nonlinearities may lead to considerable loss of assimilation skill, as compared to the utilization of a time-averaged (TA) linear observation operator. In order to understand this undesired effect, we embed VSL's formulation into the framework of fuzzy logic (FL) theory, which thereby exposes multiple representations of the principle of limiting factors. DA experiments employing three alternative growth rate functions disclose a strong link between the lack of smoothness of the growth rate function and the loss of optimality in the estimate of the TA state. Accordingly, VSL's performance as observation operator can be enhanced by resorting to smoother FL representations of the principle of limiting factors. This finding fosters new interpretations of tree-ring-growth limitation processes.

  1. Developement of new measuring techniques. A measuring system for testing GIS disconnectors in a high voltage laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Carubelli, C.; Cremonesi, F.; Santagostino, G.

    1988-10-01

    Within the framework of the cooperation between CESI (Italy) and the CPRI (Central Power Research Institute), the problem of a fast and accurate measurements systems for gas-insulated substations (GIS) disconnector testing was analyzed. The particular complexity of the transients to be studied has led to the development of a composite system in which the high frequency components are dealt with by analog techniques and medium frequency components are handled with digital techniques. Sophisticate software was developed to combine the measurement results. Further improvements are expected with the development of a fiber-optics link with an extended bandwidth and the adoption of a digital oscilloscope in order to simplify the overall management of the tests.

  2. Impact of metal overhang and guard ring techniques on breakdown voltage of Si strip sensors - 2003 IEEE nuclear science symposium, medical imaging conference, and workshop of room-temperature semiconductor detectors

    CERN Document Server

    Ranjan, K; Namrata, S; Chatterji, S; Srivastava-Ajay, K; Kumar, A; Jha, Manoj Kumar; Shivpuri, R K

    2004-01-01

    The importance of Si sensors in high-energy physics (HEP) experiments can hardly be overemphasized. However, the high luminosity and the high radiation level in the future HEP experiments, like Large Hadron Collider (LHC), has posed a serious challenge to the fabrication of Si detectors. For the safe operation over the full LHC lifetime, detectors are required to sustain very high voltage operation, well exceeding the bias voltage needed to full deplete the heavily irradiated Si sensors. Thus, the main effort in the development of Si sensors is concentrated on a design that avoids p-n junction breakdown at operational biases. Among various proposed techniques, Field-limiting Ring (FLR) (or guard ring) and Metal-Overhang (MO) are technologically simple and are suitable for vertical devices. Since high-voltage planar Si junctions are of great importance in the HEP experiments, it is very interesting to compare these two aforementioned techniques for achieving the maximum breakdown voltage under optimal conditio...

  3. Whisker maps of neuronal subclasses of the rat ventral posterior medial thalamus, identified by whole-cell voltage recording and morphological reconstruction.

    Science.gov (United States)

    Brecht, Michael; Sakmann, Bert

    2002-01-15

    Whole-cell voltage recordings were made in vivo in the ventral posterior medial nucleus (VPM) of the thalamus in urethane-anaesthetised young (postnatal day 16-24) rats. Receptive fields (RFs) on the whisker pad were mapped for 31 neurones, and 10 cells were recovered for morphological reconstruction of their dendritic arbors. Most VPM neurones had antagonistic subthreshold RFs that could be divided into excitatory and inhibitory whiskers. VPM cells comprised different classes, the most frequently occurring being single-whisker excitation (SWE) and multi-whisker excitation (MWE) cells. In SWE cells (36 % of VPM neurones), only principal whisker (PW) deflection evoked an EPSP and was followed by a single action potential (AP) or remained subthreshold. The depolarisation was terminated by a large, delayed IPSP. A stimulus evoked on average 0.74 +/- 0.46 APs (mean +/- S.D.) with short latency (8.1 +/- 1.0 ms) and small temporal scatter (0.31 +/- 0.23 ms dispersion of 50 % of the first APs). In MWE cells (29 % of VPM neurones), deflection of several whiskers evoked EPSPs. PW responses were either subthreshold EPSPs or consisted of an EPSP followed by one or several APs (0.96 +/- 0.99 APs per stimulus). AP responses were often associated with putative low-threshold calcium-dependent regenerative potentials and were followed by a small delayed IPSP. AP responses had a longer latency (12.3 +/- 2.6 ms) and larger temporal scatter (2.5 +/- 1.6 ms) than responses of SWE cells. MWE cells had a lower input resistance than SWE cells. The elongation of dendritic arbors along the representation fields of rows and arcs in VPM barreloids was weakly correlated with the subthreshold RF elongation along whisker rows and arcs, respectively. Evoked EPSP-AP responses exhibited a sharper directional tuning than subthreshold EPSPs, which in turn exhibited a sharper directional tuning than IPSPs. In conclusion, we document two main classes of VPM neurones. SWE cells responded with a

  4. New Technique for Voltage Tracking Control of a Boost Converter Based on the PSO Algorithm and LTspice

    DEFF Research Database (Denmark)

    Farhang, Peyman; Drimus, Alin; Mátéfi-Tempfli, Stefan

    2015-01-01

    the optimal solutions is run in MATLAB while it is interfaced with LTspice for simulation of the circuit using actual component models obtained from manufacturers. The PSO is utilized to solve the optimization problem in order to find the optimal parameters of MPID and PID controllers. The performances......In this paper, a new technique is proposed to design a Modified PID (MPID) controller for a Boost converter. An interface between LTspice and MATLAB is carried out to implement the Particle Swarm Optimization (PSO) algorithm. The PSO algorithm which has the appropriate capability to find out...

  5. High voltage engineering fundamentals

    CERN Document Server

    Kuffel, E; Hammond, P

    1984-01-01

    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

  6. Using informatics-enabled quality improvement techniques to meet health record documentation requirements in radiology reports.

    Science.gov (United States)

    Prevedello, Luciano M; Farkas, Cameron; Dufault, Allen; Damiano, Maria; Doubilet, Peter; Khorasani, Ramin

    2013-08-01

    Medicare requires documented teaching physician involvement (attestation) in trainee-generated radiology reports. Automated attestation statement insertion in reports expedites the process but does not comply with requirements for active attestation. We evaluated an informatics-enabled quality improvement (QI) intervention to improve health record documentation requirements for active attestation. Institutional review board approval was not needed for this QI project performed in a 776-bed tertiary/quaternary teaching hospital. The intervention consisted of (1) policy requiring staff radiologists to actively attest to trainee-generated reports by personally activating a "macro" in the reporting system and (2) a semiautomated process to detect reports missing attestation; radiologists received daily e-mail reminders until the attestation statement was inserted. A random sample of 600 of 123,561 trainee-generated radiology reports created 17 months after the intervention (May 2011) was manually reviewed to determine attestation policy adherence. The number of attestation statements added in response to reminders throughout the entire study period was also evaluated. Trend analysis of the number of report addenda containing solely the attestation statement (proxy for missing initial attestation) was performed. Of 600 reports, 594 (99%) contained the attestation statement. Monthly attestations in response to email notifications decreased from 585 to 227 by the sixth month, a 2.6-fold reduction (P < .01). No significant trend was observed the following year, indicating a sustained effect. Informatics-enabled QI techniques resulted in 99% adherence to our teaching physician attestation policy with sustained results. Similar approaches may help improve adherence to other mandated performance measures in radiology reports. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  7. A Simple Technique for Recording Root and Shoot Growth in Plants.

    Science.gov (United States)

    Murray, Philip J.; Bristow, Andrew W.

    1997-01-01

    Presents a simple method of recording root growth which can be used in schools. A slant board system was designed to facilitate access to roots to enable measurements to be made, essentially forcing the roots to grow in a two-dimensional form which allows each student to observe and record root growth over several weeks. (AIM)

  8. Urethral pressure reflectometry; a novel technique for simultaneous recording of pressure and cross-sectional area

    DEFF Research Database (Denmark)

    Aagaard, Mikael; Klarskov, Niels; Sønksen, Jens;

    2012-01-01

    in several studies. But the technique, which was based on the field gradient principle, was never implemented in the clinical setting because of technical limitations. In 2005, urethral pressure reflectometry was introduced as a new technique in female urodynamics. The technique has been shown to be more...

  9. A 5-bit time to digital converter using time to voltage conversion and integrating techniques for agricultural products analysis by Raman spectroscopy

    Directory of Open Access Journals (Sweden)

    Mahdi Rezvanyvardom

    2014-12-01

    Full Text Available Time to digital converter (TDC is a key block for time-gated single photon avalanche diode (SPAD arrays for Raman spectroscopy that applicable in the agricultural products and food analysis. In this paper a new dual slope time to digital converter that employs the time to voltage conversion and integrating techniques for digitizing the time interval input signals is presented. The reference clock frequency of the TDC is 100 MHz and the input range is theoretically unlimited. The proposed converter features high accuracy, very small average error and high linear range. Also this converter has some advantages such as low circuit complexity, low power consumption and low sensitive to the temperature, power supply and process changes (PVT compared with the time to digital converters that used preceding conversion techniques. The proposed converter uses an indirect time to digital conversion method. Therefore, our converter has the appropriate linearity without extra elements. In order to evaluate the proposed idea, an integrating time to digital converter is designed in 0.18 μm CMOS technology and was simulated by Hspice. Comparison of the theoretical and simulation results confirms the proposed TDC operation; therefore, the proposed converter is very convenient for applications which have average speed and low variations in the signal amplitude such as biomedical signals.

  10. Validation of an Improved Computer-Assisted Technique for Mining Free-Text Electronic Medical Records.

    Science.gov (United States)

    Duz, Marco; Marshall, John F; Parkin, Tim

    2017-06-29

    The use of electronic medical records (EMRs) offers opportunity for clinical epidemiological research. With large EMR databases, automated analysis processes are necessary but require thorough validation before they can be routinely used. The aim of this study was to validate a computer-assisted technique using commercially available content analysis software (SimStat-WordStat v.6 (SS/WS), Provalis Research) for mining free-text EMRs. The dataset used for the validation process included life-long EMRs from 335 patients (17,563 rows of data), selected at random from a larger dataset (141,543 patients, ~2.6 million rows of data) and obtained from 10 equine veterinary practices in the United Kingdom. The ability of the computer-assisted technique to detect rows of data (cases) of colic, renal failure, right dorsal colitis, and non-steroidal anti-inflammatory drug (NSAID) use in the population was compared with manual classification. The first step of the computer-assisted analysis process was the definition of inclusion dictionaries to identify cases, including terms identifying a condition of interest. Words in inclusion dictionaries were selected from the list of all words in the dataset obtained in SS/WS. The second step consisted of defining an exclusion dictionary, including combinations of words to remove cases erroneously classified by the inclusion dictionary alone. The third step was the definition of a reinclusion dictionary to reinclude cases that had been erroneously classified by the exclusion dictionary. Finally, cases obtained by the exclusion dictionary were removed from cases obtained by the inclusion dictionary, and cases from the reinclusion dictionary were subsequently reincluded using Rv3.0.2 (R Foundation for Statistical Computing, Vienna, Austria). Manual analysis was performed as a separate process by a single experienced clinician reading through the dataset once and classifying each row of data based on the interpretation of the free

  11. Analyzing of Dynamic Voltage Restorer in Series Compensation Voltage

    Directory of Open Access Journals (Sweden)

    Naser Parhizgar

    2012-02-01

    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.

  12. Intelligent technique for knowledge reuse of dental medical records based on case-based reasoning.

    Science.gov (United States)

    Gu, Dong-Xiao; Liang, Chang-Yong; Li, Xing-Guo; Yang, Shan-Lin; Zhang, Pei

    2010-04-01

    With the rapid development of both information technology and the management of modern medical regulation, the generation of medical records tends to be increasingly intelligent. In this paper, Case-Based Reasoning is applied to the process of generating records of dental cases. Based on the analysis of the features of dental records, a case base is constructed. A mixed case retrieval method (FAIES) is proposed for the knowledge reuse of dental records by adopting Fuzzy Mathematics, which improves similarity algorithm based on Euclidian-Lagrangian Distance, and PULL & PUSH weight adjustment strategy. Finally, an intelligent system of dental cases generation (CBR-DENT) is constructed. The effectiveness of the system, the efficiency of the retrieval method, the extent of adaptation and the adaptation efficiency are tested using the constructed case base. It is demonstrated that FAIES is very effective in terms of reducing the time of writing medical records and improving the efficiency and quality. FAIES is also proven to be an effective aid for diagnoses and provides a new idea for the management of medical records and its applications.

  13. DOCUMENTING FOR POSTERITY: ADVOCATING THE USE OF ADVANCED RECORDING TECHNIQUES FOR DOCUMENTATION IN THE FIELD OF BUILDING ARCHAEOLOGY

    Directory of Open Access Journals (Sweden)

    P. J. De Vos

    2017-08-01

    Full Text Available Since the new millennium, living in historic cities has become extremely popular in the Netherlands. As a consequence, historic environments are being adapted to meet modern living standards. Houses are constantly subjected to development, restoration and renovation. Although most projects are carried out with great care and strive to preserve and respect as much historic material as possible, nevertheless a significant amount of historical fabric disappears. This puts enormous pressure on building archaeologists that struggle to rapidly and accurately capture in situ authentic material and historical evidence in the midst of construction works. In Leiden, a medieval city that flourished during the seventeenth century and that today counts over 3,000 listed monuments, a solution to the problem has been found with the implementation of advanced recording techniques. Since 2014, building archaeologists of the city council have experienced first-hand that new recording techniques, such as laser scanning and photogrammetry, have dramatically decreased time spent on site with documentation. Time they now use to uncover, analyse and interpret the recovered historical data. Nevertheless, within building archaeology education, a strong case is made for hand drawing as a method for understanding a building, emphasising the importance of close observation and physical contact with the subject. In this paper, the use of advanced recording techniques in building archaeology is being advocated, confronting traditional educational theory with practise, and research tradition with the rapid rise of new recording technologies.

  14. Documenting for Posterity: Advocating the Use of Advanced Recording Techniques for Documentation in the Field of Building Archaeology

    Science.gov (United States)

    De Vos, P. J.

    2017-08-01

    Since the new millennium, living in historic cities has become extremely popular in the Netherlands. As a consequence, historic environments are being adapted to meet modern living standards. Houses are constantly subjected to development, restoration and renovation. Although most projects are carried out with great care and strive to preserve and respect as much historic material as possible, nevertheless a significant amount of historical fabric disappears. This puts enormous pressure on building archaeologists that struggle to rapidly and accurately capture in situ authentic material and historical evidence in the midst of construction works. In Leiden, a medieval city that flourished during the seventeenth century and that today counts over 3,000 listed monuments, a solution to the problem has been found with the implementation of advanced recording techniques. Since 2014, building archaeologists of the city council have experienced first-hand that new recording techniques, such as laser scanning and photogrammetry, have dramatically decreased time spent on site with documentation. Time they now use to uncover, analyse and interpret the recovered historical data. Nevertheless, within building archaeology education, a strong case is made for hand drawing as a method for understanding a building, emphasising the importance of close observation and physical contact with the subject. In this paper, the use of advanced recording techniques in building archaeology is being advocated, confronting traditional educational theory with practise, and research tradition with the rapid rise of new recording technologies.

  15. Data Matching Concepts and Techniques for Record Linkage, Entity Resolution, and Duplicate Detection

    CERN Document Server

    Christen, Peter

    2012-01-01

    Data matching (also known as record or data linkage, entity resolution, object identification, or field matching) is the task of identifying, matching and merging records that correspond to the same entities from several databases or even within one database. Based on research in various domains including applied statistics, health informatics, data mining, machine learning, artificial intelligence, database management, and digital libraries, significant advances have been achieved over the last decade in all aspects of the data matching process, especially on how to improve the accuracy of da

  16. A new technique to study transient conductivity under pulsed monochromatic light in Cr-doped GaAs using acoustoelectric voltage measurement

    Science.gov (United States)

    Tabib-Azar, Massood

    1991-01-01

    The transient conductivity of high-resistivity Bridgman-grown Cr-doped GaAs under pulsed monochromatic light is monitored using transverse acoustoelectric voltage (TAV) at 83 K. Keeping the photon flux constant, the height and transient time constant at the TAV are used to calculate the energy dependence of the trap density and its cross section, respectively. Two prominent trap profiles with peak trap densities of approximately 10 to the 17th/cu cm eV near the valence and the conduction bands are detected. These traps have very small capture cross sections in the range of 10 to the -23 to 10 to the -21st cm sq. A phenomenon similar to the persistent photoconductivity with transient time constants in excess of a few seconds in high-resistivity GaAs at T = 83 K is also detected using this technique. These long relaxation times are readily explained by the spatial separation of the photo-excited electron-hole pairs and the small capture cross section and large density of trap distribution near the conduction band.

  17. Behaviour of total surface charge in SiO{sub 2}-Si system under short-pulsed ultraviolet irradiation cycles characterised by surface photo voltage technique

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Ban-Hong [Material Characterization Department, Shin Etsu Handotai (M) Sdn. Bhd., Ulu Klang, Selangor (Malaysia); Lee, Wah-Pheng [Faculty of Engineering, Multimedia University, Persiaran Multimedia, Cyberjaya, 63100 Selangor (Malaysia); Yow, Ho-Kwang, E-mail: hkyow@mmu.edu.my [Faculty of Engineering, Multimedia University, Persiaran Multimedia, Cyberjaya, 63100 Selangor (Malaysia); Tou, Teck-Yong [Faculty of Engineering, Multimedia University, Persiaran Multimedia, Cyberjaya, 63100 Selangor (Malaysia)

    2009-04-15

    Effects of time-accumulated ultraviolet (UV) irradiation and surface treatment on thermally oxidized p-type silicon wafers were investigated by using the surface photo voltage (SPV) technique via the direct measurement of the total surface charge, Q{sub SC}. The rise and fall times of Q{sub sc} curves, as a function of accumulated UV irradiation, depended on the thermal oxide thickness. A simple model was proposed to explain the time-varying characteristics of Q{sub sc} based on the UV-induced bond breaking of SiOH and SiH, and photoemission of bulk electrons to wafer surface where O{sub 2}{sup -} charges were formed. While these mechanisms resulted in charge variations and hence in Q{sub sc}, these could be removed by rinsing the silicon wafers in de-ionized water followed by spin-dry or blow-dry by an ionizer fan. Empirical parameters were used in the model simulations and curve-fitting of Q{sub SC}. The simulated results suggested that initial changes in the characteristic behaviour of Q{sub sc} were mainly due to the net changes in the positive and negative charges, but subsequently were dominated by the accumulation of O{sub 2}{sup -} during the UV irradiation.

  18. Measuring a Pig's Preference for Suspended Toys by Using an Automated Recording Technique

    NARCIS (Netherlands)

    Zonderland, J.J.; Vermeer, H.M.; Vereijken, P.F.G.; Spoolder, H.A.M.

    2003-01-01

    Not all suspended materials for finishing pigs are equally suited to meet the natural behavior of the animal, but the required physical properties of the toys have yet to be identified. The present study aimed to develop a labor saving electronic recording device for animal-material interactions. Fu

  19. Comparing SO2 Emissions to Seismic and Acoustic Records: the Value and Limitations of the new UV Camera Technique

    Science.gov (United States)

    Dalton, M. P.; Waite, G. P.; Nadeau, P. A.; Watson, I. M.

    2008-12-01

    SO2 emission measurements are an important component of monitoring volcanic eruption processes. Owing mainly to limitations in the temporal resolution of measurements, the goal of merging a gas flux record with other geophysical datasets (seismic, acoustic) with the aim of investigating subsurface processes has been elusive. In recent years, ground-based, ultraviolet (UV) digital cameras have improved upon previous methods of SO2 observation by capturing a large portion of the plume in one measurement- a single image. The UV digital camera can record at up to 1Hz, producing a data set that is more comparable with other monitoring techniques, allowing for a more precise record of SO2 flux, and directly providing the plume speed. Many monitoring advantages are gained by using this technique, but the accuracy and limitations require thorough investigation. The effect of some user-controlled parameters, include image exposure length, the diameter of the lens aperture, the regularity of calibration cell imaging, and the use of the single or paired bandpass filters, are addressed in this study. Laboratory and field experiments were conducted to clarify methodological consequences and quantify accuracy. Digital images of calibration cells were collected under varying observational conditions, and SO2 retrieval results from a coal power plant plume were compared to direct sampling measurements. The results indicate that the UV camera retrieval compares favorably with direct sampling methods; that careful attention must be paid to exposure times; and that there is some latitude in the calibration cell conversion technique. A multi-instrument field campaign was undertaken at Pacaya volcano, Guatemala to relate complementary high-temporal-resolution datasets. Between January 5 and January 9, 2008 SO2 flux was recorded at Pacaya using the UV camera. These measurements were coincident with recordings from a temporary network of five broadband seismometers and five low

  20. Unconventional Specimen Preparation Techniques Using High Resolution Low Voltage Field Emission Scanning Electron Microscopy to Study Cell Motility, Host Cell Invasion, and Internal Cell Structures in Toxoplasma gondii

    Science.gov (United States)

    Schatten, Heide; Ris, Hans

    2002-04-01

    Apicomplexan parasites employ complex and unconventional mechanisms for cell locomotion, host cell invasion, and cell division that are only poorly understood. While immunofluorescence and conventional transmission electron microscopy have been used to answer questions about the localization of some cytoskeletal proteins and cell organelles, many questions remain unanswered, partly because new methods are needed to study the complex interactions of cytoskeletal proteins and organelles that play a role in cell locomotion, host cell invasion, and cell division. The choice of fixation and preparation methods has proven critical for the analysis of cytoskeletal proteins because of the rapid turnover of actin filaments and the dense spatial organization of the cytoskeleton and its association with the complex membrane system. Here we introduce new methods to study structural aspects of cytoskeletal motility, host cell invasion, and cell division of Toxoplasma gondii, a most suitable laboratory model that is representative of apicomplexan parasites. The novel approach in our experiments is the use of high resolution low voltage field emission scanning electron microscopy (LVFESEM) combined with two new specimen preparation techniques. The first method uses LVFESEM after membrane extraction and stabilization of the cytoskeleton. This method allows viewing of actin filaments which had not been possible with any other method available so far. The second approach of imaging the parasite's ultrastructure and interactions with host cells uses semithick sections (200 nm) that are resin de-embedded (Ris and Malecki, 1993) and imaged with LVFESEM. This method allows analysis of structural detail in the parasite before and after host cell invasion and interactions with the membrane of the parasitophorous vacuole as well as parasite cell division.

  1. Single-intensity-recording optical encryption technique based on phase retrieval algorithm and QR code

    Science.gov (United States)

    Wang, Zhi-peng; Zhang, Shuai; Liu, Hong-zhao; Qin, Yi

    2014-12-01

    Based on phase retrieval algorithm and QR code, a new optical encryption technology that only needs to record one intensity distribution is proposed. In this encryption process, firstly, the QR code is generated from the information to be encrypted; and then the generated QR code is placed in the input plane of 4-f system to have a double random phase encryption. For only one intensity distribution in the output plane is recorded as the ciphertext, the encryption process is greatly simplified. In the decryption process, the corresponding QR code is retrieved using phase retrieval algorithm. A priori information about QR code is used as support constraint in the input plane, which helps solve the stagnation problem. The original information can be recovered without distortion by scanning the QR code. The encryption process can be implemented either optically or digitally, and the decryption process uses digital method. In addition, the security of the proposed optical encryption technology is analyzed. Theoretical analysis and computer simulations show that this optical encryption system is invulnerable to various attacks, and suitable for harsh transmission conditions.

  2. Vestibulo-Oculomotor Reflex Recording Using the Scleral Search Coil Technique. Review of Peripheral Vestibular Disorders

    Science.gov (United States)

    Boleas-Aguirre, Marisol; Migliaccio, Amerio A.; Carey, John P.

    2010-01-01

    Our goal is to review vestibulo-oculomotor reflex (VOR) studies on several peripheral vestibular disorders (Ménière’s disease, vestibular neuritis, benign paroxysmal positional vertigo, superior canal dehiscence syndrome, and vestibular neuroma), using the scleral search coil (SSC) technique. Head movements are detected by vestibular receptors and the elicited VOR is responsible for compensatory 3 dimensional eye movements. Therefore, to study the VOR it is necessary to assess the direction and velocity of 3 dimensional head, and eye movements. This can be achieved using the SSC technique. Interaction between a scleral search coil and an alternating magnetic field generates an electrical signal that is proportional to eye position. Ideally, eye rotation axis is aligned with head rotation axis and VOR gain (eye velocity/head velocity) for horizontal and vertical head rotations is almost 1. The VOR gain, however, for torsional head rotations is smaller and about 0.7. PMID:17683700

  3. Optimización de Tensión en Redes de Distribución utilizando Técnicas de Optimización Evolutiva Power Distribution Network Voltage Optimization using Evolutionary Optimization Techniques

    Directory of Open Access Journals (Sweden)

    Francisco G Montoya

    2006-01-01

    Full Text Available Se ha implementado una técnica que resuelve el problema del desvío de perfil óptimo de tensión en una red eléctrica de distribución. Para una red eléctrica, se puede ajustar la tensión de sus nodos, actuando en los cambiadores de tomas de los transformadores de distribución de dicha red. La idea básica persigue obtener un conjunto de valores para las tomas de los transformadores, que aplicadas en dichas máquinas, consigan aproximar, lo máximo posible, las tensiones de los nudos eléctricos que controlan a la tensión nominal. Para ello se utilizan técnicas matemáticas basadas en algoritmos evolutivos desarrolladas en entorno Matlab®. Se han obtenido perfiles óptimos de tensión, minimizando la desviación cuadrática media de las tensiones.A new technique to solve the problem of deviation of the optimum voltage profile in power distribution networks has been developed. The node voltage can be adjusted, operating the under-load tap changer (ULTC. The main idea is to get a set of values for the ULTC’s tape changer that can approximate the node voltage, that they are controlling, to the nominal node voltage. To solve the problem, evolutionary algorithm techniques implemented in Matlab® have been developed. Optimum voltage profiles are been obtained, minimizing the mean square root of node voltage.

  4. Evaluation of the reproducibility of two techniques used to determine and record centric relation in angle's class I patients

    Directory of Open Access Journals (Sweden)

    Fernanda Paixão

    2007-08-01

    Full Text Available The centric relation is a mandibular position that determines a balance relation among the temporomandibular joints, the chew muscles and the occlusion. This position makes possible to the dentist to plan and to execute oral rehabilitation respecting the physiological principles of the stomatognathic system. The aim of this study was to investigate the reproducibility of centric relation records obtained using two techniques: Dawson's Bilateral Manipulation and Gysi's Gothic Arch Tracing. Twenty volunteers (14 females and 6 males with no dental loss, presenting occlusal contacts according to those described in Angle's I classification and without signs and symptoms of temporomandibular disorders were selected. All volunteers were submitted five times with a 1-week interval, always in the same schedule, to the Dawson's Bilateral Manipulation and to the Gysi's Gothic Arch Tracing with aid of an intraoral apparatus. The average standard error of each technique was calculated (Bilateral Manipulation 0.94 and Gothic Arch Tracing 0.27. Shapiro-Wilk test was applied and the results allowed application of Student's t-test (sampling error of 5%. The techniques showed different degrees of variability. The Gysi's Gothic Arch Tracing was found to be more accurate than the Bilateral Manipulation in reproducing the centric relation records.

  5. A Voltage Quality Detection Method

    DEFF Research Database (Denmark)

    Chen, Zhe; Wei, Mu

    2008-01-01

    This paper presents a voltage quality detection method based on a phase-locked loop (PLL) technique. The technique can detect the voltage magnitude and phase angle of each individual phase under both normal and fault power system conditions. The proposed method has the potential to evaluate vario...... power quality disturbances, such as interruptions, sags and imbalances. Simulation studies have been performed. The effectiveness of the proposed method has been demonstrated under the simulated typical power disturbances....

  6. A Digitally Dynamic Power Supply Technique for 16-Channel 12 V-Tolerant Stimulator Realized in a 0.18-μm 1.8-V/3.3-V Low-Voltage CMOS Process.

    Science.gov (United States)

    Luo, Zhicong; Ker, Ming-Dou; Yang, Tzu-Yi; Cheng, Wan-Hsueh

    2017-07-18

    A new digitally dynamic power supply technique for 16-channel 12-V-tolerant stimulator is proposed and realized in a 0.18-μm 1.8-V/3.3-V CMOS process. The proposed stimulator uses four stacked transistors as the pull-down switch and pull-up switch to withstand 4 times the nominal supply voltage (4 × V DD). With the dc input voltage of 3.3 V, the regulated three-stage charge pump, which is capable of providing 11.3-V voltage at 3-mA loading current, achieves dc conversion efficiency of up to 69% with 400-pF integrated capacitance. Power consumption is reduced by implementing the regulated charge pump to provide a dynamic dc output voltage with a 0.5-V step. The proposed digitally dynamic power supply technique, which is implemented by using a p-type metal oxide semiconductor (PMOS) inverter with pull-down current source and digital controller, greatly improves the power efficiency of a system. The silicon area of the stimulator is approximately 3.5 mm2 for a 16-channel implementation. The functionalities of the proposed stimulator have been successfully verified through animal test.

  7. A lossless data reduction technique for wireless EEG recorders and its use in selective data filtering for seizure monitoring.

    Science.gov (United States)

    Chengliang Dai; Bailey, Christopher

    2015-01-01

    This paper presents a time-domain based lossless data reduction technique called Log2 Sub-band encoding, which is designed for reducing the size of data recorded on a wireless electroencephalogram (EEG) recorder. A data reduction unit can help to save power from the wireless transceiver and from the storage medium since it allows lower data transmission and read/write rates, and then extends the life time of the battery on the device. Our compression ratio(CR) results show that Log2 Sub-band encoding is comparable and even superior to Huffman coding, a well known entropy encoding method, whilst requiring minimal hardware resource, and it can also be used to extract features from EEG to achieve seizure detection during the compression process. The power consumption when compressing the EEG data is presented to evaluate the system0s overall improvement on its power performance, and our results indicate that a noticeable power saving can be achieved with our technique. The possibility of applying this method to other biomedical signals will also be noted.

  8. Accurate Switched-Voltage voltage averaging circuit

    OpenAIRE

    金光, 一幸; 松本, 寛樹

    2006-01-01

    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.

  9. Development of a Technique for Representing Lightning Arresters in the Surge Simulations based on the FDTD Method and its Application to the Calculation of Lightning-Induced Voltages on a Distribution Line

    Science.gov (United States)

    Tatematsu, Akiyoshi; Noda, Taku

    Recently, the FDTD (Finite Difference Time Domain) method, which directly solves Maxwell's equations, has been applied to lightning surge problems involving electrical wires in three-dimensional arrangements, such as power and telecommunication circuits. Lightning arresters are installed to protect the circuits from abnormal voltages due to lightning, for example. We have already proposed a technique for representing a lightning arrester in the FDTD method. However, this technique simply represents the V-I characteristics of the arrester using just three parameters and requires a method for avoiding the numerical oscillation due to the nonlinear characteristics of the arrester. In this paper, we propose a new technique for representing the V-I characteristics of the arrester in detail using the piecewise linear function defined by several points and for improving the numerical stability without the method for avoiding the numerical oscillation. Using a test circuit, the proposed technique is validated by comparing the results calculated by the FDTD method with those by the EMTP (ElectroMagnetic Transients Program) which is a circuit-theory-based simulation program. Finally, as an example of applying the proposed technique, we calculate lightning-induced voltages on a distribution line with a lightning arrester. The calculated results by the FDTD method agree well with those by a conventional method based on circuit theroy.

  10. Record extension for short-gauged water quality parameters using a newly proposed robust version of the Line of Organic Correlation technique

    Directory of Open Access Journals (Sweden)

    B. Khalil

    2012-07-01

    Full Text Available In many situations the extension of hydrological or water quality time series at short-gauged stations is required. Ordinary least squares regression (OLS of any hydrological or water quality variable is a traditional and commonly used record extension technique. However, OLS tends to underestimate the variance in the extended records, which leads to underestimation of high percentiles and overestimation of low percentiles, given that the data are normally distributed. The development of the line of organic correlation (LOC technique is aimed at correcting this bias. On the other hand, the Kendall-Theil robust line (KTRL method has been proposed as an analogue of OLS with the advantage of being robust in the presence of outliers. Given that water quality data are characterised by the presence of outliers, positive skewness and non-normal distribution of data, a robust record extension technique is more appropriate. In this paper, four record-extension techniques are described, and their properties are explored. These techniques are OLS, LOC, KTRL and a new technique proposed in this paper, the robust line of organic correlation technique (RLOC. RLOC includes the advantage of the LOC in reducing the bias in estimating the variance, but at the same time it is also robust in the presence of outliers. A Monte Carlo study and empirical experiment were conducted to examine the four techniques for the accuracy and precision of the estimate of statistical moments and over the full range of percentiles. Results of the Monte Carlo study showed that the OLS and KTRL techniques have serious deficiencies as record-extension techniques, while the LOC and RLOC techniques are nearly similar. However, RLOC outperforms OLS, KTRL and LOC when using real water quality records.

  11. Record extension for short-gauged water quality parameters using a newly proposed robust version of the line of organic correlation technique

    Directory of Open Access Journals (Sweden)

    B. Khalil

    2012-04-01

    Full Text Available In many situations the extension of hydrological or water quality time series at short-gauged stations is required. Ordinary least squares regression (OLS of any hydrological or water quality variable is a traditional and commonly used record extension technique. However, OLS tends to underestimate the variance in the extended records, which leads to underestimation of high percentiles and overestimation of low percentiles, given that the data is normally distributed. The development of the line of organic correlation (LOC technique is aimed at correcting this bias. On the other hand, the Kendall-Theil robust line (KTRL method has been proposed as an analogue of OLS with the advantage of being robust in the presence of outliers. Given that water quality data are characterised by the presence of outliers, positive skewness and non-normal distribution of data, a robust record extension technique is more appropriate. In this paper, four record-extension techniques are described, and their properties are explored. These techniques are OLS, LOC, KTRL and a new technique proposed in this paper, the robust line of organic correlation technique (RLOC. RLOC includes the advantage of the LOC in reducing the bias in estimating the variance, but at the same time it is also robust to the presence of outliers. A Monte Carlo study and empirical experiment were conducted to examine the four techniques for the accuracy and precision of the estimate of statistical moments and over the full range of percentiles. Results of the Monte Carlo study showed that the OLS and KTRL techniques have serious deficiencies as record-extension techniques, while the LOC and RLOC techniques are nearly similar. However, RLOC outperforms OLS, KTRL and LOC when using real water quality records.

  12. Long-term invariant parameters obtained from 24-h Holter recordings: A comparison between different analysis techniques

    Science.gov (United States)

    Cerutti, Sergio; Esposti, Federico; Ferrario, Manuela; Sassi, Roberto; Signorini, Maria Gabriella

    2007-03-01

    Over the last two decades, a large number of different methods had been used to study the fractal-like behavior of the heart rate variability (HRV). In this paper some of the most used techniques were reviewed. In particular, the focus is set on those methods which characterize the long memory behavior of time series (in particular, periodogram, detrended fluctuation analysis, rescale range analysis, scaled window variance, Higuchi dimension, wavelet-transform modulus maxima, and generalized structure functions). The performances of the different techniques were tested on simulated self-similar noises (fBm and fGn) for values of α, the slope of the spectral density for very small frequency, ranging from -1 to 3 with a 0.05 step. The check was performed using the scaling relationships between the various indices. DFA and periodogram showed the smallest mean square error from the expected values in the range of interest for HRV. Building on the results obtained from these tests, the effective ability of the different methods in discriminating different populations of patients from RR series derived from Holter recordings, was assessed. To this extent, the Noltisalis database was used. It consists of a set of 30, 24-h Holter recordings collected from healthy subjects, patients suffering from congestive heart failure, and heart transplanted patients. All the methods, with the exception at most of rescale range analysis, were almost equivalent in distinguish between the three groups of patients. Finally, the scaling relationships, valid for fBm and fGn, when empirically used on HRV series, also approximately held.

  13. Accuracy Assessment of a Canal-Tunnel 3d Model by Comparing Photogrammetry and Laserscanning Recording Techniques

    Science.gov (United States)

    Charbonnier, P.; Chavant, P.; Foucher, P.; Muzet, V.; Prybyla, D.; Perrin, T.; Grussenmeyer, P.; Guillemin, S.

    2013-07-01

    With recent developments in the field of technology and computer science, conventional methods are being supplanted by laser scanning and digital photogrammetry. These two different surveying techniques generate 3-D models of real world objects or structures. In this paper, we consider the application of terrestrial Laser scanning (TLS) and photogrammetry to the surveying of canal tunnels. The inspection of such structures requires time, safe access, specific processing and professional operators. Therefore, a French partnership proposes to develop a dedicated equipment based on image processing for visual inspection of canal tunnels. A 3D model of the vault and side walls of the tunnel is constructed from images recorded onboard a boat moving inside the tunnel. To assess the accuracy of this photogrammetric model (PM), a reference model is build using static TLS. We here address the problem comparing the resulting point clouds. Difficulties arise because of the highly differentiated acquisition processes, which result in very different point densities. We propose a new tool, designed to compare differences between pairs of point cloud or surfaces (triangulated meshes). Moreover, dealing with huge datasets requires the implementation of appropriate structures and algorithms. Several techniques are presented : point-to-point, cloud-to-cloud and cloud-to-mesh. In addition farthest point resampling, octree structure and Hausdorff distance are adopted and described. Experimental results are shown for a 475 m long canal tunnel located in France.

  14. Comparison of infrared spectroscopy techniques: developing an efficient method for high resolution analysis of sediment properties from long records

    Science.gov (United States)

    Hahn, Annette; Rosén, Peter; Kliem, Pierre; Ohlendorf, Christian; Persson, Per; Zolitschka, Bernd; Pasado Science Team

    2010-05-01

    The analysis of sediment samples in visible to mid-infrared spectra is ideal for high-resolution records. It requires only small amounts (0.01-0.1g dry weight) of sample material and facilitates rapid and cost efficient analysis of a wide variety of biogeochemical properties on minerogenic and organic substances (Kellner et al. 1998). One of these techniques, the Diffuse Reflectance Fourier Transform Infrared Spectrometry (DRIFTS), has already been successfully applied to lake sediment from very different settings and has shown to be a promising technique for high resolution analyses of long sedimentary records on glacial-interglacial timescales (Rosén et al. 2009). However, the DRIFTS technique includes a time-consuming step where sediment samples are mixed with KBr. To assess if alternative and more rapid infrared (IR) techniques can be used, four different IR spectroscopy techniques are compared for core catcher sediment samples from Laguna Potrok Aike - an ICDP site located in southernmost South America. Partial least square (PLS) calibration models were developed using the DRIFTS technique. The correlation coefficients (R) for correlations between DRIFTS-inferred and conventionally measured biogeochemical properties show values of 0.80 for biogenic silica (BSi), 0.95 for total organic carbon (TOC), 0.91 for total nitrogen (TN), and 0.92 for total inorganic carbon (TIC). Good statistical performance was also obtained by using the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy ATR-FTIRS technique which requires less sample preparation. Two devices were used, the full-sized Bruker Equinox 252 and the smaller and less expensive Bruker Alpha. R for ATR-FTIRS-inferred and conventionally measured biogeochemical properties were 0.87 (BSi), 0.93 (TOC), 0.90 (TN), and 0.91 (TIC) for the Alpha, and 0.78 (TOC), 0.85 (TN), 0.79 (TIC) for the Equinox 252 device. As the penetration depth of the IR beam is frequency dependent, a firm surface contact of

  15. AN ANTHOLOGY OF THE DISTINGUISHED ACHIEVEMENTS IN SCIENCE AND TECHNIQUE. PART 28: PORTRAITS OF LEGENDARY PHYSICISTS OF «HIGH-VOLTAGE BRIGADE» OF UPHTI

    Directory of Open Access Journals (Sweden)

    M.I. Baranov

    2015-11-01

    Full Text Available Purpose. Description of the basic distinguished scientific achievements of members of «high-voltage brigade» of the Ukrainian Physical-Technical Institute (UPhTI and future Academicians in area of nuclear physics − Valter A.C., Sinelnikov C.D., Leypunskiy A.I. and Latyshev G.D. Methodology. Scientific approaches at treatment and systematization of physical knowledges. Historical method at research of development in Ukraine and Russia of nuclear physics and mastering of intranuclear energy for military and peaceful aims. Results. The basic creative and vital stages, and also prominent scientific results, obtained by the indicated scientists in the area of nuclear physics, physics of high energies and nuclear energy, are resulted in the compressed and systematized way. Some technical descriptions created by these Kharkov physicists of powerful high-voltage electrostatic and linear dynamitrons and protons, and also nuclear reactors fast-neutron are indicated. Originality. Firstly in the area of history of scientific-technological authoritative enough scientist-electro-physicist, which is engaged not alone ten of years by creation of powerful generators of very high voltage and large currents, and also presents a theoretical electrophysics a wide reader a scientifically-historical essay with not popular details about the first in the USSR breaking up the physicists of UPhTI of atomic kernel of lithium by artificially speed-up protons. Firstly the basic distinguished scientific achievements of the considered physicists-nuclear engineers are resulted in the concentrated way. Practical value. Scientific popularization of physical knowledges and achievements of the known compatriots, bringing in a big contribution to development of nuclear physics, physicists of high energies and nuclear energy.

  16. Research of reduced common-mode voltage technique with nonzero vector pulse width modulation for three-phase inverters%三相逆变器的无零矢量共模电压抑制技术研究

    Institute of Scientific and Technical Information of China (English)

    章勇高; 邝光健; 龙立中

    2013-01-01

    The common-mode suppression techniques with nonzero vector pulse width modulation (NZPWM) for three-phase inverters are studied. They are random state pulse width modulation (RSPWM), active zero state PWM1 (AZSPWM1), active zero state PWM3 (AZSPWM3) and near state PWM (NSPWM). Firstly, the operation areas of modulation factor and reference voltage vector with different modulation strategies are analyzed. The results show that RSPWM has a smaller operation area than other three NZPWM and is suitable for the application with lower modulation ratio. Secondly, the DC voltage utilization rate and output harmonic of different NZPWM are researched and compared with that of traditional space vector modulation (SVM) by using theoretical analysis and simulation. The results show that AZPWM1, AZPWM3 and NSPWM can not only suppress the common mode voltage of three-phase inverters efficiently, but also maintain high DC voltage utilization rate. However, three-phase inverters with NSPWM have the higher output harmonic comparing with the traditional SVM. The research results provide theoretical basis and instruction for the selection of common mode voltage suppression technique with NZPWM for three-phase inverters and its further study.%  研究了三相逆变器的 RSPWM、AZSPWM1、AZSPWM3和 NSPWM 无零矢量共模电压抑制技术。首先,分析了不同调制策略的调制因数和参考电压矢量的工作区间,说明了 RSPWM 的工作区间较小,适用于低调制比工作场合。再次,利用理论分析和仿真方法,研究了无零矢量调制策略的直流电压利用率和输出谐波特性,并与传统 SVM 调制策略比较。结果表明,AZSPWM1、AZSPWM3和 NSPWM 调制策略能够有效地抑制三相逆变器共模电压,同时保持了较高的直流电压利用率。但相对 SVM 调制策略,三相逆变器的输出谐波含量有所增大。研究结果为三相逆变器的无零矢量共模电压抑制技术的选用及进一步研究提供了理论依据和指导。

  17. Voltage-gated lipid ion channels

    DEFF Research Database (Denmark)

    Blicher, Andreas; Heimburg, Thomas Rainer

    2013-01-01

    Synthetic lipid membranes can display channel-like ion conduction events even in the absence of proteins. We show here that these events are voltage-gated with a quadratic voltage dependence as expected from electrostatic theory of capacitors. To this end, we recorded channel traces and current...

  18. Reconstruction of Cell Surface Densities of Ion Pumps, Exchangers, and Channels from mRNA Expression, Conductance Kinetics, Whole-Cell Calcium, and Current-Clamp Voltage Recordings, with an Application to Human Uterine Smooth Muscle Cells.

    Directory of Open Access Journals (Sweden)

    Jolene Atia

    2016-04-01

    Full Text Available Uterine smooth muscle cells remain quiescent throughout most of gestation, only generating spontaneous action potentials immediately prior to, and during, labor. This study presents a method that combines transcriptomics with biophysical recordings to characterise the conductance repertoire of these cells, the 'conductance repertoire' being the total complement of ion channels and transporters expressed by an electrically active cell. Transcriptomic analysis provides a set of potential electrogenic entities, of which the conductance repertoire is a subset. Each entity within the conductance repertoire was modeled independently and its gating parameter values were fixed using the available biophysical data. The only remaining free parameters were the surface densities for each entity. We characterise the space of combinations of surface densities (density vectors consistent with experimentally observed membrane potential and calcium waveforms. This yields insights on the functional redundancy of the system as well as its behavioral versatility. Our approach couples high-throughput transcriptomic data with physiological behaviors in health and disease, and provides a formal method to link genotype to phenotype in excitable systems. We accurately predict current densities and chart functional redundancy. For example, we find that to evoke the observed voltage waveform, the BK channel is functionally redundant whereas hERG is essential. Furthermore, our analysis suggests that activation of calcium-activated chloride conductances by intracellular calcium release is the key factor underlying spontaneous depolarisations.

  19. Reconstruction of Cell Surface Densities of Ion Pumps, Exchangers, and Channels from mRNA Expression, Conductance Kinetics, Whole-Cell Calcium, and Current-Clamp Voltage Recordings, with an Application to Human Uterine Smooth Muscle Cells.

    Science.gov (United States)

    Atia, Jolene; McCloskey, Conor; Shmygol, Anatoly S; Rand, David A; van den Berg, Hugo A; Blanks, Andrew M

    2016-04-01

    Uterine smooth muscle cells remain quiescent throughout most of gestation, only generating spontaneous action potentials immediately prior to, and during, labor. This study presents a method that combines transcriptomics with biophysical recordings to characterise the conductance repertoire of these cells, the 'conductance repertoire' being the total complement of ion channels and transporters expressed by an electrically active cell. Transcriptomic analysis provides a set of potential electrogenic entities, of which the conductance repertoire is a subset. Each entity within the conductance repertoire was modeled independently and its gating parameter values were fixed using the available biophysical data. The only remaining free parameters were the surface densities for each entity. We characterise the space of combinations of surface densities (density vectors) consistent with experimentally observed membrane potential and calcium waveforms. This yields insights on the functional redundancy of the system as well as its behavioral versatility. Our approach couples high-throughput transcriptomic data with physiological behaviors in health and disease, and provides a formal method to link genotype to phenotype in excitable systems. We accurately predict current densities and chart functional redundancy. For example, we find that to evoke the observed voltage waveform, the BK channel is functionally redundant whereas hERG is essential. Furthermore, our analysis suggests that activation of calcium-activated chloride conductances by intracellular calcium release is the key factor underlying spontaneous depolarisations.

  20. 红外辐射测温技术在煤矿高压电器检测中的应用%Infrared radiation thermometry techniques in the coal high voltage electrical detection

    Institute of Scientific and Technical Information of China (English)

    王兴举; 黄宗建; 李进曌

    2014-01-01

    Infraredradiation thermometry techniques have real-time,convenient and non-destructive,which is widely used in electrical products,temperature detection,especially in high-voltage electrical equipment due to coal mining complex run construction environment,conventional means is difficult to accurately measure the temperature changes,and infrared radiation thermometry can quickly and accurately measure high voltage electrical coal mines.This article from the infrared radiation thermometry in the coal high voltage electrical temperature measurement standpoint,focusing on the formation mechanism of the infrared radiation thermometry,testing methods and testing techniques to note,as the actual production process to provide a reliable theoretical basis.%红外辐射测温技术具备了实时、便捷以及非破坏性等特点,广泛用于电器产品温度的检测中,特别是煤矿高压电器设备由于复杂的运行施工环境,常规手段很难准确的测量温度的变化,而红外辐射测温能够迅速准确的对煤矿高压电器进行测量。本文主要从红外辐射测温技术在煤矿高压电器温度的测量方面出发,重点研究了红外辐射测温的形成机理、测试手段以及需要注意的测试技巧,为生产实际过程中提供一个可靠的理论依据。

  1. Whole-cell recordings of calcium and potassium currents in acutely isolated smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    Qing Cai; Zhong-Liang Zhu; Xiao-Li Fan

    2006-01-01

    AIM: To record calcium and potassium currents in acutely isolated smooth muscle cells of mesenteric arterial branches in rats.METHODS: Smooth muscle cells were freshly isolated by collagenase digest and mechanical trituration with polished pipettes. Patch clamp technique in whole-cell mode was employed to record calcium and potassium currents.RESULTS: The procedure dissociated smooth muscle cells without impairing the electrophysiological characteristics of the cells. The voltage-gated Ca2+ and potassium currents were successfully recorded using whole-cell patch clamp configuration.CONCLUSION: The method dissociates smooth muscle cells from rat mesenteric arterial branches. Voltage-gated channel currents can be recorded in this preparation.

  2. Effects of Voltage-Gated K+ Channel on Cell Proliferation in Multiple Myeloma

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-01-01

    Full Text Available Objective. To study the effects and underlying mechanisms of voltage-gated K+ channels on the proliferation of multiple myeloma cells. Methods. RPMI-8226 MM cell line was used for the experiments. Voltage-gated K+ currents and the resting potential were recorded by whole-cell patch-clamp technique. RT-PCR detected Kv channel mRNA expression. Cell viability was analyzed with MTT assay. Cell counting system was employed to monitor cell proliferation. DNA contents and cell volume were analyzed by flow cytometry. Results. Currents recorded in RPMI-8226 cells were confirmed to be voltage-gated K+ channels. A high level of Kv1.3 mRNA was detected but no Kv3.1 mRNA was detected in RPMI-8226 cells. Voltage-gated K+ channel blocker 4-aminopyridine (4-AP (2 mM depolarized the resting potential from −42 ± 1.7 mV to −31.8 ± 2.8 mV (P0.05. Conclusions. In RPMI-8226, voltage-gated K+ channels are involved in proliferation and cell cycle progression its influence on the resting potential and cell volume may be responsible for this process; the inhibitory effect of the voltage-gated K+ channel blocker on RPMI-8226 cell proliferation is a phase-specific event.

  3. A technique for simultaneously improving the product of cutoff frequency-breakdown voltage and thermal stability of SOI SiGe HBT

    Science.gov (United States)

    Fu, Qiang; Zhang, Wan-Rong; Jin, Dong-Yue; Zhao, Yan-Xiao; Wang, Xiao

    2016-12-01

    The product of the cutoff frequency and breakdown voltage (fT×BVCEO) is an important figure of merit (FOM) to characterize overall performance of heterojunction bipolar transistor (HBT). In this paper, an approach to introducing a thin N+-buried layer into N collector region in silicon-on-insulator (SOI) SiGe HBT to simultaneously improve the FOM of fT×BVCEO and thermal stability is presented by using two-dimensional (2D) numerical simulation through SILVACO device simulator. Firstly, in order to show some disadvantages of the introduction of SOI structure, the effects of SOI insulation layer thickness (TBOX) on fT, BVCEO, and the FOM of fT×BVCEO are presented. The introduction of SOI structure remarkably reduces the electron concentration in collector region near SOI substrate insulation layer, obviously reduces fT, slightly increases BVCEO to some extent, but ultimately degrades the FOM of fT×BVCEO. Although the fT, BVCEO, and the FOM of fT×BVCEO can be improved by increasing SOI insulator SiO2 layer thickness TBOX in SOI structure, the device temperature and collector current are increased due to lower thermal conductivity of SiO2 layer, as a result, the self-heating effect of the device is enhanced, and the thermal stability of the device is degraded. Secondly, in order to alleviate the foregoing problem of low electron concentration in collector region near SOI insulation layer and the thermal stability resulting from thick TBOX, a thin N+-buried layer is introduced into collector region to not only improve the FOM of fT×BVCEO, but also weaken the self-heating effect of the device, thus improving the thermal stability of the device. Furthermore, the effect of the location of the thin N+-buried layer in collector region is investigated in detail. The result show that the FOM of fT×BVCEO is improved and the device temperature decreases as the N+-buried layer shifts toward SOI substrate insulation layer. The approach to introducing a thin N+-buried layer

  4. Fehlende Daten beim Record Linkage von Prozess- und Befragungsdaten : ein empirischer Vergleich ausgewählter Missing Data Techniken (Missing data in the record linkage of process and survey data : An empirical comparison of selected missing data techniques)

    OpenAIRE

    Krug, Gerhard

    2009-01-01

    "To compare different missing data techniques, in this paper I use a survey where participants were among other things asked permission for combining the survey with administrative data (record linkage). For those who refuse their permission I set their survey answers to missing, creating pseudo-missing data due to an empirical relevant but unknown mechanism (compared to the statistical simulation of a missing data process). OLS Regression is performed using Complete Case Analysis (CCA), Mult...

  5. Low-Voltage Continuous Electrospinning Patterning.

    Science.gov (United States)

    Li, Xia; Li, Zhaoying; Wang, Liyun; Ma, Guokun; Meng, Fanlong; Pritchard, Robyn H; Gill, Elisabeth L; Liu, Ye; Huang, Yan Yan Shery

    2016-11-30

    Electrospinning is a versatile technique for the construction of microfibrous and nanofibrous structures with considerable potential in applications ranging from textile manufacturing to tissue engineering scaffolds. In the simplest form, electrospinning uses a high voltage of tens of thousands volts to draw out ultrafine polymer fibers over a large distance. However, the high voltage limits the flexible combination of material selection, deposition substrate, and control of patterns. Prior studies show that by performing electrospinning with a well-defined "near-field" condition, the operation voltage can be decreased to the kilovolt range, and further enable more precise patterning of fibril structures on a planar surface. In this work, by using solution dependent "initiators", we demonstrate a further lowering of voltage with an ultralow voltage continuous electrospinning patterning (LEP) technique, which reduces the applied voltage threshold to as low as 50 V, simultaneously permitting direct fiber patterning. The versatility of LEP is shown using a wide range of combination of polymer and solvent systems for thermoplastics and biopolymers. Novel functionalities are also incorporated when a low voltage mode is used in place of a high voltage mode, such as direct printing of living bacteria; the construction of suspended single fibers and membrane networks. The LEP technique reported here should open up new avenues in the patterning of bioelements and free-form nano- to microscale fibrous structures.

  6. Automatic voltage imbalance detector

    Science.gov (United States)

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

    1984-01-01

    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.

  7. Practical considerations in voltage stability assessment

    Energy Technology Data Exchange (ETDEWEB)

    Kundur, P.; Gao, B. [Powertech Labs. Inc., Surrey, BC (Canada)

    1994-12-31

    This paper deals with some of the most important practical issues related to voltage stability assessment of large practical systems. A brief discussion of the practical aspects of voltage stability problem and prevention of voltage instability is given first, followed by descriptions of different analytical techniques and tools for voltage stability analysis. Presentations of analytical tools is focused on the VSTAB program which incorporates the modal analysis, continuation power flow, and shortest distance to instability techniques, Finally, an example case study of a practical large system is presented. The case study illustrates how modal analysis is used to determine the most effective load shedding scheme for preventing voltage instability. (author) 15 refs., 2 figs., 2 tabs.

  8. The Most Frequent Energy Theft Techniques and Hazards in Present Power Energy Consumption: Cyber Security in Smart Metering Low Voltage Network

    DEFF Research Database (Denmark)

    Czechowski, Robert; Kosek, Anna Magdalena

    2016-01-01

    One of the challenging problems when it comes to electric energy distribution is electricity theft. Regardless of whether the deed is done on a large scale or only by a single consumer, it is a problem that generates losses and its detection is not always easy. One of the crucial factors making...... the issue of electricity theft still relevant is the common physical access of the end users to the installations or meters. The article presents not only the factors encouraging energy consumers to engage in dishonest behavior and the techniques they use to achieve the intended result, but also technical...... measures aimed at detecting such actions. The discussed technical issues can prove useful in designing increasingly refined security measures and ways to detect electricity theft....

  9. Voltage-gated lipid ion channels

    DEFF Research Database (Denmark)

    Blicher, Andreas; Heimburg, Thomas Rainer

    2013-01-01

    Synthetic lipid membranes can display channel-like ion conduction events even in the absence of proteins. We show here that these events are voltage-gated with a quadratic voltage dependence as expected from electrostatic theory of capacitors. To this end, we recorded channel traces and current...... histograms in patch-experiments on lipid membranes. We derived a theoretical current-voltage relationship for pores in lipid membranes that describes the experimental data very well when assuming an asymmetric membrane. We determined the equilibrium constant between closed and open state and the open...... probability as a function of voltage. The voltage-dependence of the lipid pores is found comparable to that of protein channels. Lifetime distributions of open and closed events indicate that the channel open distribution does not follow exponential statistics but rather power law behavior for long open times...

  10. VOLTAGE MONITORING INSTRUMENT WITH FAST-TRANSIENTS CAPTURE CAPABILITY

    Directory of Open Access Journals (Sweden)

    M. Gracida-Aguirre

    2003-09-01

    Full Text Available A monitoring instrument aimed at recording the voltage levels at residential installations is described. Its main feature is the capability ot recording short transients, lasting less than one cycle, while requiring a rather modest amount of memory for long monitoring periods. The instrument uses synchronous sampling of the voltage waveform, and its response to outages has been optimized.

  11. An Analysis of Translation Strategies for Professional English for Audio Recording Techniques%录音专业英语翻译策略探究

    Institute of Scientific and Technical Information of China (English)

    黄艺平

    2013-01-01

    随着现代传媒科技的发展,音频技术与艺术广泛的结合,越来越深入人们的生活。录音英语的专业性对中西方的跨文化交流形成了一定的障碍。该文通过对录音专业英语的特点进行梳理,结合尤金·奈达的等效翻译理论,力图探索出行之有效的录音专业英语翻译转化之路。%With the development of modern media technology, audio recording technology is widely integrated into artistic forms, which increasingly influences people’s life. The special characteristics of professional English for audio recording technology has somewhat become an obstacle in the cross-cultural exchange between the west and the east. This paper attempts to find some applica-ble translation strategies for professional English for audio recording techniques by analyzing the linguistic features of professional English for audio recording techniques from the perspective of Eugene A. Nida’s Functional Equivalence Theory.

  12. A Comparison between Electrochemical Impedance Spectroscopy and Incremental Capacity-Differential Voltage as Li-ion Diagnostic Techniques to Identify and Quantify the Effects of Degradation Modes within Battery Management Systems

    Science.gov (United States)

    Pastor-Fernández, Carlos; Uddin, Kotub; Chouchelamane, Gael H.; Widanage, W. Dhammika; Marco, James

    2017-08-01

    Degradation of Lithium-ion batteries is a complex process that is caused by a variety of mechanisms. For simplicity, ageing mechanisms are often grouped into three degradation modes (DMs): conductivity loss (CL), loss of active material (LAM) and loss of lithium inventory (LLI). State of Health (SoH) is typically the parameter used by the Battery Management System (BMS) to quantify battery degradation based on the decrease in capacity and the increase in resistance. However, the definition of SoH within a BMS does not currently include an indication of the underlying DMs causing the degradation. Previous studies have analysed the effects of the DMs using incremental capacity and differential voltage (IC-DV) and electrochemical impedance spectroscopy (EIS). The aim of this study is to compare IC-DV and EIS on the same data set to evaluate if both techniques provide similar insights into the causes of battery degradation. For an experimental case of parallelized cells aged differently, the effects due to LAM and LLI were found to be the most pertinent, outlining that both techniques are correlated. This approach can be further implemented within a BMS to quantify the causes of battery ageing which would support battery lifetime control strategies and future battery designs.

  13. Reduced Voltage Scaling in Clock Distribution Networks

    Directory of Open Access Journals (Sweden)

    Khader Mohammad

    2009-01-01

    Full Text Available We propose a novel circuit technique to generate a reduced voltage swing (RVS signals for active power reduction on main buses and clocks. This is achieved without performance degradation, without extra power supply requirement, and with minimum area overhead. The technique stops the discharge path on the net that is swinging low at a certain voltage value. It reduces active power on the target net by as much as 33% compared to traditional full swing signaling. The logic 0 voltage value is programmable through control bits. If desired, the reduced-swing mode can also be disabled. The approach assumes that the logic 0 voltage value is always less than the threshold voltage of the nMOS receivers, which eliminate the need of the low to high voltage translation. The reduced noise margin and the increased leakage on the receiver transistors using this approach have been addressed through the selective usage of multithreshold voltage (MTV devices and the programmability of the low voltage value.

  14. Size and voltage dependence of effective anisotropy in sub-100-nm perpendicular magnetic tunnel junctions

    Science.gov (United States)

    Piotrowski, Stephan K.; Bapna, Mukund; Oberdick, Samuel D.; Majetich, Sara A.; Li, Mingen; Chien, C. L.; Ahmed, Rizvi; Victora, R. H.

    2016-07-01

    Magnetic tunnel junctions with perpendicular magnetic anisotropy are investigated using a conductive atomic force microscope. The 1.23 -nm Co40Fe40B20 recording layer coercivity exhibits a size dependence which suggests single-domain behavior for diameters ≤100 nm. Focusing on devices with diameters smaller than 100 nm, we determine the effect of voltage and size on the effective device anisotropy Keff using two different techniques. Keff is extracted both from distributions of the switching fields of the recording and reference layers and from measurement of thermal fluctuations of the recording layer magnetization when a field close to the switching field is applied. The results from both sets of measurements reveal that Keff increases monotonically with decreasing junction diameter, consistent with the size dependence of the demagnetization energy density. We demonstrate that Keff can be controlled with a voltage down to the smallest size measured, 64 nm.

  15. A Performance Analysis of Modified Mid-Square and Mid-Product Techniques to Minimize the Redundancy for Retrieval of Database Records

    Directory of Open Access Journals (Sweden)

    K. M. Sundaram

    2010-01-01

    Full Text Available Problem statement: An important tool in the field of education methodology is examination. As far as teaching-learning-evaluation process is concerned, the major task associated with the objective-type examination system is the administration of question paper setting. The lack of expertise and time are the major constraints that are encountered in the task of setting objective type question papers. During retrieval of records from a objective type question bank, redundancy may occur. To solve this problem, an approach needed to retrieve records from a database without redundancy. Approach: The task associated in generating the required collection of questions from a question bank, with minimal redundancy as far as possible in the retrieval of records from the question bank using mid-square and mid-product techniques for random number generation were discussed in this study. Results: A modified approach was identified and handled to generate random numbers and used to retrieve records from a database Conclusion: The suggested modified approach was more suitable for retrieving records from a database of even smaller size.

  16. Review on different experimental techniques developed for recording force-deformation behaviour of soft tissues; with a view to surgery simulation applications.

    Science.gov (United States)

    Afshari, Elnaz; Rostami, Mostafa; Farahmand, Farzam

    2017-05-01

    Different experimental techniques which have been developed to obtain data related to force-deformation behaviour of soft tissues play an important role in realistically simulating surgery processes as well as medical diagnoses and minimally invasive procedures. Indeed, an adequate quantitative description of soft-tissue-mechanical-behaviour requires high-quality experimental data to be obtained and analysed. In this review article we will first scan the motivations and basic technical issues on surgery simulation. Then, we will concentrate on different experimental techniques developed for recording force-deformation (stress-strain) behaviour of soft tissues with focussing on the in-vivo experimental setups. We will thoroughly review the available techniques by classifying them to four groups; elastography, indentation, aspiration and grasping techniques. The evolutions, advantages and limitations of each technique will be presented by a historical review. At the end, a discussion is given with the aim of summarising the proposed points and predicting the future of techniques utilised in extracting data related to force-deformation behaviour.

  17. Voltage modulation of propagating spin waves in Fe

    Energy Technology Data Exchange (ETDEWEB)

    Nawaoka, Kohei; Shiota, Yoichi; Miwa, Shinji; Tamura, Eiiti [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); CREST, Japan Science Technology, Kawaguchi, Saitama 332-0012 (Japan); Tomita, Hiroyuki; Mizuochi, Norikazu; Shinjo, Teruya [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Suzuki, Yoshishige, E-mail: suzuki-y@mp.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); CREST, Japan Science Technology, Kawaguchi, Saitama 332-0012 (Japan); Display and Semiconductor Physics Department, Korea University, Sejong 339-700 (Korea, Republic of)

    2015-05-07

    The effect of a voltage application on propagating spin waves in single-crystalline 5 nm-Fe layer was investigated. Two micro-sized antennas were employed to excite and detect the propagating spin waves. The voltage effect was characterized using AC lock-in technique. As a result, the resonant field of the magnetostatic surface wave in the Fe was clearly modulated by the voltage application. The modulation is attributed to the voltage induced magnetic anisotropy change in ferromagnetic metals.

  18. Stray voltage mitigation

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-09

    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.

  19. High voltage engineering

    CERN Document Server

    Rizk, Farouk AM

    2014-01-01

    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

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

    OpenAIRE

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

    2013-01-01

    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...

  1. Activation of Ih and TTX-sensitive sodium current at subthreshold voltages during CA1 pyramidal neuron firing.

    Science.gov (United States)

    Yamada-Hanff, Jason; Bean, Bruce P

    2015-10-01

    We used dynamic clamp and action potential clamp techniques to explore how currents carried by tetrodotoxin-sensitive sodium channels and HCN channels (Ih) regulate the behavior of CA1 pyramidal neurons at resting and subthreshold voltages. Recording from rat CA1 pyramidal neurons in hippocampal slices, we found that the apparent input resistance and membrane time constant were strongly affected by both conductances, with Ih acting to decrease apparent input resistance and time constant and sodium current acting to increase both. We found that both Ih and sodium current were active during subthreshold summation of artificial excitatory postsynaptic potentials (EPSPs) generated by dynamic clamp, with Ih dominating at less depolarized voltages and sodium current at more depolarized voltages. Subthreshold sodium current-which amplifies EPSPs-was most effectively recruited by rapid voltage changes, while Ih-which blunts EPSPs-was maximal for slow voltage changes. The combined effect is to selectively amplify rapid EPSPs. We did similar experiments in mouse CA1 pyramidal neurons, doing voltage-clamp experiments using experimental records of action potential firing of CA1 neurons previously recorded in awake, behaving animals as command voltages to quantify flow of Ih and sodium current at subthreshold voltages. Subthreshold sodium current was larger and subthreshold Ih was smaller in mouse neurons than in rat neurons. Overall, the results show opposing effects of subthreshold sodium current and Ih in regulating subthreshold behavior of CA1 neurons, with subthreshold sodium current prominent in both rat and mouse CA1 pyramidal neurons and additional regulation by Ih in rat neurons.

  2. Simultaneous recordings of human microsaccades and drifts with a contemporary video eye tracker and the search coil technique.

    Directory of Open Access Journals (Sweden)

    Michael B McCamy

    Full Text Available Human eyes move continuously, even during visual fixation. These "fixational eye movements" (FEMs include microsaccades, intersaccadic drift and oculomotor tremor. Research in human FEMs has grown considerably in the last decade, facilitated by the manufacture of noninvasive, high-resolution/speed video-oculography eye trackers. Due to the small magnitude of FEMs, obtaining reliable data can be challenging, however, and depends critically on the sensitivity and precision of the eye tracking system. Yet, no study has conducted an in-depth comparison of human FEM recordings obtained with the search coil (considered the gold standard for measuring microsaccades and drift and with contemporary, state-of-the art video trackers. Here we measured human microsaccades and drift simultaneously with the search coil and a popular state-of-the-art video tracker. We found that 95% of microsaccades detected with the search coil were also detected with the video tracker, and 95% of microsaccades detected with video tracking were also detected with the search coil, indicating substantial agreement between the two systems. Peak/mean velocities and main sequence slopes of microsaccades detected with video tracking were significantly higher than those of the same microsaccades detected with the search coil, however. Ocular drift was significantly correlated between the two systems, but drift speeds were higher with video tracking than with the search coil. Overall, our combined results suggest that contemporary video tracking now approaches the search coil for measuring FEMs.

  3. Simultaneous recordings of human microsaccades and drifts with a contemporary video eye tracker and the search coil technique.

    Science.gov (United States)

    McCamy, Michael B; Otero-Millan, Jorge; Leigh, R John; King, Susan A; Schneider, Rosalyn M; Macknik, Stephen L; Martinez-Conde, Susana

    2015-01-01

    Human eyes move continuously, even during visual fixation. These "fixational eye movements" (FEMs) include microsaccades, intersaccadic drift and oculomotor tremor. Research in human FEMs has grown considerably in the last decade, facilitated by the manufacture of noninvasive, high-resolution/speed video-oculography eye trackers. Due to the small magnitude of FEMs, obtaining reliable data can be challenging, however, and depends critically on the sensitivity and precision of the eye tracking system. Yet, no study has conducted an in-depth comparison of human FEM recordings obtained with the search coil (considered the gold standard for measuring microsaccades and drift) and with contemporary, state-of-the art video trackers. Here we measured human microsaccades and drift simultaneously with the search coil and a popular state-of-the-art video tracker. We found that 95% of microsaccades detected with the search coil were also detected with the video tracker, and 95% of microsaccades detected with video tracking were also detected with the search coil, indicating substantial agreement between the two systems. Peak/mean velocities and main sequence slopes of microsaccades detected with video tracking were significantly higher than those of the same microsaccades detected with the search coil, however. Ocular drift was significantly correlated between the two systems, but drift speeds were higher with video tracking than with the search coil. Overall, our combined results suggest that contemporary video tracking now approaches the search coil for measuring FEMs.

  4. An enhanced security solution for electronic medical records based on AES hybrid technique with SOAP/XML and SHA-1.

    Science.gov (United States)

    Kiah, M L Mat; Nabi, Mohamed S; Zaidan, B B; Zaidan, A A

    2013-10-01

    This study aims to provide security solutions for implementing electronic medical records (EMRs). E-Health organizations could utilize the proposed method and implement recommended solutions in medical/health systems. Majority of the required security features of EMRs were noted. The methods used were tested against each of these security features. In implementing the system, the combination that satisfied all of the security features of EMRs was selected. Secure implementation and management of EMRs facilitate the safeguarding of the confidentiality, integrity, and availability of e-health organization systems. Health practitioners, patients, and visitors can use the information system facilities safely and with confidence anytime and anywhere. After critically reviewing security and data transmission methods, a new hybrid method was proposed to be implemented on EMR systems. This method will enhance the robustness, security, and integration of EMR systems. The hybrid of simple object access protocol/extensible markup language (XML) with advanced encryption standard and secure hash algorithm version 1 has achieved the security requirements of an EMR system with the capability of integrating with other systems through the design of XML messages.

  5. Voltage verification unit

    Science.gov (United States)

    Martin, Edward J.

    2008-01-15

    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.

  6. Comparison of disinfectants by immersion and spray atomization techniques on the linear dimensional stability of different interocclusal recording materials: An in vitro study.

    Science.gov (United States)

    Gounder, Revathy; Vikas, B V J

    2016-01-01

    To evaluate and compare the effect of 0.5% chlorhexidine gluconate, 1% sodium hypochlorite, and 2% glutaraldehyde by immersion and spray atomization technique on the linear dimensional stability of Jet bite, Aluwax and Ramitec interocclusal recording materials. Three representative materials: Jet bite (addition silicone), Aluwax and Ramitec (polyether) were mixed according to manufacturer's instructions and then specimens were prepared according to the specifications of ISO 4823. All the specimens except the control (distilled water) were treated with disinfectant solutions (0.5% chlorhexidine gluconate, 1% sodium hypochlorite, and 2% glutaraldehyde) for 30 and 60 min (n = 10) by spray and immersion technique. Once removed from the solutions, the test samples were washed in water for 15 s, dried and measured after 24 h 3 times using a measuring microscope with an accuracy of 0.0001 mm. Two-way ANOVA and Tukey's test with significance level of 5% were used to assess the statistical data (α = 0.05). All groups showed no significant difference statistically, in linear dimension when disinfected for 30 min by spray or immersion technique. Polyether had significantly higher dimensional variation when immersed in sodium hypochlorite for 60 min. Addition silicone showed the least dimensional change which ranged from 0.024% to 0.05%, followed by polyether from 0.004% to 0.171% and Aluwax from 0.146% to 0.228%. To preserve the dimensions and surface of the recording materials and effective microbial elimination, restrictions should be applied in the method of disinfection and time duration. However, using the disinfectants either by spray or immersion technique, the dimensional change was <0.5% which was not clinically significant according to the American Dental Association specification no. 19 criteria within the first 24 h.

  7. F1FO ATPase vesicle preparation and technique for performing patch clamp recordings of submitochondrial vesicle membranes.

    Science.gov (United States)

    Sacchetti, Silvio; Alavian, Kambiz N; Lazrove, Emma; Jonas, Elizabeth A

    2013-05-04

    Mitochondria are involved in many important cellular functions including metabolism, survival(1), development and, calcium signaling(2). Two of the most important mitochondrial functions are related to the efficient production of ATP, the energy currency of the cell, by oxidative phosphorylation, and the mediation of signals for programmed cell death(3). The enzyme primarily responsible for the production of ATP is the F1FO-ATP synthase, also called ATP synthase(4-5). In recent years, the role of mitochondria in apoptotic and necrotic cell death has received considerable attention. In apoptotic cell death, BCL-2 family proteins such as Bax enter the mitochondrial outer membrane, oligomerize and permeabilize the outer membrane, releasing pro-apoptotic factors into the cytosol(6). In classic necrotic cell death, such as that produced by ischemia or excitotoxicity in neurons, a large, poorly regulated increase in matrix calcium contributes to the opening of an inner membrane pore, the mitochondrial permeability transition pore or mPTP. This depolarizes the inner membrane and causes osmotic shifts, contributing to outer membrane rupture, release of pro-apoptotic factors, and metabolic dysfunction. Many proteins including Bcl-xL(7) interact with F1FO ATP synthase, modulating its function. Bcl-xL interacts directly with the beta subunit of F1FO ATP synthase, and this interaction decreases a leak conductance within the F1FOATPasecomplex, increasing the net transport of H+ by F1FO during F1FO ATPase activity(8) and thereby increasing mitochondrial efficiency. To study the activity and modulation of the ATP synthase, we isolated from rodent brain submitochondrial vesicles (SMVs) containing F1FO ATPase. The SMVs retain the structural and functional integrity of the F1FO ATPase as shown in Alavian et al. Here, we describe a method that we have used successfully for the isolation of SMVs from rat brain and we delineate the patch clamp technique to analyze channel activity (ion

  8. Insight into the function of the obturator internus muscle in humans: observations with development and validation of an electromyography recording technique.

    Science.gov (United States)

    Hodges, Paul W; McLean, Linda; Hodder, Joanne

    2014-08-01

    There are no direct recordings of obturator internus muscle activity in humans because of difficult access for electromyography (EMG) electrodes. Functions attributed to this muscle are based on speculation and include hip external rotation/abduction, and a role in stabilization as an "adjustable ligament" of the hip. Here we present (1) a technique to insert intramuscular EMG electrodes into obturator internus plus (2) the results of an investigation of obturator internus activity relative to that of nearby hip muscles during voluntary hip efforts in two hip positions and a weight-bearing task. Fine-wire electrodes were inserted with ultrasound guidance into obturator internus, gluteus maximus, piriformis and quadratus femoris in ten participants. Participants performed ramped and maximal isometric hip efforts (open kinetic chain) into flexion/extension, abduction/adduction, and internal/external rotation, and hip rotation to end range in standing. Analysis of the relationship between activity of the obturator internus and the other hip muscles provided evidence of limited contamination of the recordings with crosstalk. Obturator internus EMG amplitude was greatest during hip extension, then external rotation then abduction, with minimal to no activation in other directions. Obturator internus EMG was more commonly the first muscle active during abduction and external rotation than other muscles. This study describes a viable and valid technique to record obturator internus EMG and provides the first evidence of its activation during simple functions. The observation of specificity of activation to certain force directions questions the hypothesis of a general role in hip stabilisation regardless of force direction.

  9. Voltage stability and controllability indices for multimachine power systems

    Energy Technology Data Exchange (ETDEWEB)

    Vournas, C.D. [National Technical Univ., Athens (Greece). Electrical Energy Systems Lab.

    1995-08-01

    This paper presents a voltage stability index (VSI) and a voltage controllability index (VCI), related to the eigenvalues of mxm matrices in a multimachine power system made up of m synchronous generators and a number of infinite buses. System loads can have an arbitrary voltage sensitivity described by generalized voltage exponents. These nonlinear loads are linearized around an operating point and incorporated into a modified admittance matrix, which is subsequently reduced to the generator terminals using an efficient algorithm and sparsity techniques. The indices proposed are tested in a practical system and it is demonstrated that they provide a timely warning during a sequence of events leading to voltage collapse.

  10. Application of Double Elbow-bar Upsetting and Shape-forming Technique to Production of High-voltage Electrical Product%双肘杆镦锻成形工艺的应用

    Institute of Scientific and Technical Information of China (English)

    武泾元; 高励学

    2013-01-01

    高压电气产品中,活塞杆和接头类零件属于关键零件,且应用较多,这类零件属于长轴类带法兰件,目前,采用的加工方式是用棒料直接加工成形,材料利用率低,工艺性差.笔者分析了活塞杆和接头类零件的形状特点,认为采用双肘杆镦锻工艺制坯,解决了材料浪费问题,降低了零件制造成本,提高了零件抗拉强度.阐述了双肘杆镦锻模具设计、成形工艺、热处理工艺等方面的内容.%Piston rods and connector-type parts are critical parts in high-voltage electrical products. These parts belong to' long axis with flange' class, and the existing shape-forming process is of directly machining bar with low material utilization and efficiency. In this paper, shape features of the piston rods and connector-type parts are analyzed, and double elbow-bar upsetting technique is suggested to save material, shorten processing time, reduce manufacturing costs and increase tensile intensity of the parts. Moreover, the design of double elbow-bar upsetting mold, the molding process, and the heat treatment are discussed.

  11. 故障录波器后台分析软件关键问题研究%Research on key technique of fault recorder background analysis software

    Institute of Scientific and Technical Information of China (English)

    郭振华; 江亚群; 杨帅雄; 梁勇超; 黄纯

    2011-01-01

    This paper studies the difficulties and key technique of designing power fault record analysis software of fault record device. Firstly, the algorithm of calculating waveform vertical coordinate with consideration of unified waveform scaling is proposed according to the characteristics and requirements of the power fault record waveform analysis and displaying. Then the computer double buffer drawing method is adopted to avoid graphics flicker which happened in traditional Windows graphics plot. In the IEC COMTRADE formatted fault recording file, the recording device samples the signal with different sampling rates in different periods; in order to estimate cross-period signal parameters, a dual sampling rate parameter algorithm based on discrete Fourier transform is given. The power fault record analysis system developed by Visual C++6.0 has friendly man-machine interface and excellent performance, which has been used in engineering practice.%对故障录波装置中录波分析软件设计中的难点和关键技术进行了研究.根据电力故障录波波形分析、显示的特点和要求,提出统一考虑波形缩放的波形显示曲线纵坐标的计算方法.采用计算机双缓存绘图方法,解决了传统Windows绘图闪烁问题,改善了显示效果.针对IEC C0MTRADE格式录波文件分时段多频率采样的特点,提出基于离散傅里叶变换的双采样速率波形参数估计算法,实现了波形参数的跨时段计算.采用Visual C++6.0设计的电力故障录波分析系统人机界面友好,性能优良,已应用于工程实践.

  12. High Voltage Distribution

    Science.gov (United States)

    Norbeck, Edwin; Miller, Michael; Onel, Yasar

    2010-11-01

    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.

  13. Low-voltage gyrotrons

    Science.gov (United States)

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

    2013-03-01

    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).

  14. High voltage and electrical insulation engineering

    CERN Document Server

    Arora, Ravindra

    2011-01-01

    "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"--

  15. Improving Low Voltage Ride Through Capability of Wind Generators Using Dynamic Voltage Restorer

    Science.gov (United States)

    Sivasankar, Gangatharan; Suresh Kumar, Velu

    2014-08-01

    The increasing wind power integration with power grid has forced the situation to improve the reliability of wind generators for stable operation. One important problem with induction generator based wind farm is its low ride through capability to the grid voltage disturbance. Any disturbance such as voltage dip may cause wind farm outages. Since wind power contribution is in predominant percentage, such outages may lead to stability problem. The proposed strategy is to use dynamic voltage controller (DVR) to compensate the voltage disturbance. The DVR provides the wind generator the ability to remain connected in grid and improve the reliability. The voltage dips due to symmetrical and unsymmetrical faults are considered for analysis. The vector control scheme is employed for fault compensation which uses software phase locked loop scheme and park dq0 transformation technique. Extensive simulation results are included to illustrate the control and operation of DVR.

  16. Device for monitoring cell voltage

    Science.gov (United States)

    Doepke, Matthias [Garbsen, DE; Eisermann, Henning [Edermissen, DE

    2012-08-21

    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.

  17. High voltage pulse generator

    Science.gov (United States)

    Fasching, George E.

    1977-03-08

    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.

  18. Evidence for electrical remodelling of the atrial myocardium in patients with atrial fibrillation. A study using the monophasic action potential recording technique.

    Science.gov (United States)

    Hertervig, Eva J; Yuan, Shiwen; Carlson, Jonas; Kongstad-Rasmussen, Ole; Olsson, S Bertil

    2002-01-01

    Experimental studies have shown that remodelling of the atrial myocardium is linked to the occurrence and perpetuation of atrial fibrillation (AF). Clinical evidence, however, is insufficient. We recorded monophasic action potentials (MAP) during AF from one to three sites in the right atrium in seven patients with chronic AF (CAF) and in 11 patients with paroxysmal AF (PAF). The fibrillatory (FF) interval between two consecutive upstrokes of the MAP was measured using a computer-assisted manual method. The mean, median, 15th, 10th, 5th percentile and shortest FF intervals were calculated in each patient and used as estimates of the local atrial effective refractory period (AERP) during AF. In three patients burst pacing at 400 and 500 beats min(-1) was delivered during the MAP recording. In nine patients, the AERP was also tested using the extra stimulus technique during sinus rhythm. Thirty-eight recordings were obtained. The shortest FF interval was significantly shorter in patients with CAF as compared with that in patients with PAF (50+/-13 vs. 72+/-31 ms, P<005). Similar differences were seen in the mean, median, 15th, 10th, and 5th percentile FF interval. The AERP during sinusrhythm was significantly longer than the estimated AERPs (P<0 05 to P<0.01) in the nine patients. There was no significant difference in FF interval before and after the burst pacing in the three patients. The AERP was significantly shortened during AF, as compared with that during sinus rhythm, and the AERP shortening was more marked in patients with CAF than in patients with PAF. These clinical findings support the connection between the electrical remodelling and the occurrence and/ or perpetuation of the AF.

  19. 五相电压源逆变器的空间矢量脉宽调制方法研究%Research of Space Vector PWM Techniques for Five-phase Voltage Source Inverter

    Institute of Scientific and Technical Information of China (English)

    高宏伟; 杨贵杰; 刘剑

    2014-01-01

    To improve the DC bus voltage utilization of five-phase voltage source inverter (VSI) and reduce the harmonic component of output phase voltages, a space vector pulse width modulation (SVPWM) algorithm of five-phase VSI based on adjacent four voltage vectors was proposed. According to the value of modulation index, the modulation range could be divided into sine modulation region and non-sine modulation region. In sine modulation region, the output phase voltages are standard sine waves without any harmonic component through allocating the action time of space vector appropriately. In non-sine modulation region, through optimizing the voltage vector in harmonic subspace, not only the DC bus voltage utilization is improved effectively, but also the harmonic component of output phase voltages is minimized. Simulation and experimental results verify the correctness and feasibility of the proposed algorithm.%为提高五相电压源逆变器(voltage source inverter,VSI)的直流母线电压利用率,减少输出相电压中所含的谐波分量,提出一种改进的基于最近四矢量的五相 VSI 空间矢量脉宽调制算法。根据调制系数的不同,将整个调制范围分为正弦调制区和非正弦调制区。在正弦调制区,通过合理分配空间矢量的作用时间,使得输出相电压为标准正弦波形,不含有任何谐波成分;在非正弦调制区,通过对谐波子空间内的电压矢量进行优化控制,在进一步提高直流母线电压利用率的同时,保证输出相电压中所含谐波分量更少,使逆变器工作在最优状态。仿真和实验结果验证了所提算法的正确性和可行性。

  20. Low-power low-voltage superior-order curvature corrected voltage reference

    Science.gov (United States)

    Popa, Cosmin

    2010-06-01

    A complementary metal oxide semiconductor (CMOS) voltage reference with a logarithmic curvature-correction will be presented. The first-order compensation is realised using an original offset voltage follower (OVF) block as a proportional to absolute temperature (PTAT) voltage generator, with the advantages of reducing the silicon area and of increasing accuracy by replacing matched resistors with matched transistors. The new logarithmic curvature-correction technique will be implemented using an asymmetric differential amplifier (ADA) block for compensating the logarithmic temperature dependent term from the first-order compensated voltage reference. In order to increase the circuit accuracy, an original temperature-dependent current generator will be designed for computing the exact type of the implemented curvature-correction. The relatively small complexity of the current squarer allows an important increasing of the circuit accuracy that could be achieved by increasing the current generator complexity. As a result of operating most of the MOS transistors in weak inversion, the original proposed voltage reference could be valuable for low-power applications. The circuit is implemented in 0.35 μm CMOS technology and consumes only 60μA for t = 25°C, being supplied at the minimal supply voltage V DD = 1.75V. The temperature coefficient of the reference voltage is 8.7 ppm/°C, while the line sensitivity is 0.75 mV/V for a supply voltage between 1.75 V and 7 V.

  1. Calculation of buffer batteries with voltage-adding storage batteries

    Energy Technology Data Exchange (ETDEWEB)

    Boldin, R.V.; Koloskov, A.A.; Ratner, G.B.; Sharov, V.N.

    1982-01-01

    A technique is proposed for buffer storage batteries of the NKG type with voltage-adding storage batteries. These batteries (B) guarantee comparatively narrow range of change in the voltage for load with discharge of the storage batteries of the main B to the assigned minimum voltage. The purpose of the calculation is to determine the number of voltage-adding B and the number of storage batteries in each of them. The initial data for calculation are minimum and maximum values of voltage for load and storage batteries of the main B. Expressions have been obtained for determining the depth of the discharge and the final expression for determining the depth of the discharge and the final discharge voltage of the storage batteries of each voltage-adding B. The necessary formulas are presented and the order for making the calculation is given.

  2. Voltage measurements at the vacuum post-hole convolute of the Z pulsed-power accelerator

    Directory of Open Access Journals (Sweden)

    E. M. Waisman

    2014-12-01

    Full Text Available Presented are voltage measurements taken near the load region on the Z pulsed-power accelerator using an inductive voltage monitor (IVM. Specifically, the IVM was connected to, and thus monitored the voltage at, the bottom level of the accelerator’s vacuum double post-hole convolute. Additional voltage and current measurements were taken at the accelerator’s vacuum-insulator stack (at a radius of 1.6 m by using standard D-dot and B-dot probes, respectively. During postprocessing, the measurements taken at the stack were translated to the location of the IVM measurements by using a lossless propagation model of the Z accelerator’s magnetically insulated transmission lines (MITLs and a lumped inductor model of the vacuum post-hole convolute. Across a wide variety of experiments conducted on the Z accelerator, the voltage histories obtained from the IVM and the lossless propagation technique agree well in overall shape and magnitude. However, large-amplitude, high-frequency oscillations are more pronounced in the IVM records. It is unclear whether these larger oscillations represent true voltage oscillations at the convolute or if they are due to noise pickup and/or transit-time effects and other resonant modes in the IVM. Results using a transit-time-correction technique and Fourier analysis support the latter. Regardless of which interpretation is correct, both true voltage oscillations and the excitement of resonant modes could be the result of transient electrical breakdowns in the post-hole convolute, though more information is required to determine definitively if such breakdowns occurred. Despite the larger oscillations in the IVM records, the general agreement found between the lossless propagation results and the results of the IVM shows that large voltages are transmitted efficiently through the MITLs on Z. These results are complementary to previous studies [R. D. McBride et al., Phys. Rev. ST Accel. Beams 13, 120401 (2010

  3. Voltage Regulators for Photovoltaic Systems

    Science.gov (United States)

    Delombard, R.

    1986-01-01

    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.

  4. To Implement Energy Efficient of Integer Unit by Higher Voltage Flip Flop Based on Minimum operating Dual Supply Voltage Techinque

    Directory of Open Access Journals (Sweden)

    M. Subhashini,

    2014-06-01

    Full Text Available To achieve the most energy-efficient operation, this brief presents a circuit design technique for separating the power supply voltage (VDD of flip-flops (FFs from that of combinational circuits, called the higher voltage FF (HVFF. Although VDD scaling can reduce the energy, the minimum operating voltage (VDDmin of FFs prevents the operation at the optimum supply voltage that minimizes the energy, because the VDDmin of FFs is higher than the optimum supply voltage. In HVFF, the VDD of combinational logic gates is reduced below the VDDmin of FFs while keeping the VDD of FFs at their VDDmin. This makes it possible to minimize the energy without power and delay penalties at the nominal supply voltage (1.2 V as well as without FF topological difications. A four bit alu is designed in these paper by using dual supply voltage usig DSCH.

  5. Cryocooled Josephson standards for AC voltage metrology

    Science.gov (United States)

    Durandetto, P.; Sosso, A.; Monticone, E.; Trinchera, B.; Fretto, M.; Lacquaniti, V.

    2017-05-01

    The Josephson effect is worldwide used as a basis for constant reference voltages in national metrological institutes and in calibration laboratories of industry. Research on Josephson voltage standards is aiming at a fundamental change also in the metrology of the volt for AC and arbitrary waveforms: programmable Josephson voltage standards converting a digital code into a quantum-accurate stepwise waveform are already available in primary laboratories and even more advanced standards for converting sub-nanosecond binary coded pulses into any arbitrary signal with quantum accuracy are now actively developed and tested. A new experimental setup based on a two-stage Gifford-McMahon cryocooler has been developed at INRiM for the operation of AC-Josephson voltage standards. Among its distinct features, the possibility of employing both the aforementioned techniques (programmable and pulsed Josephson voltage standards) is particularly interesting. Quantum-based AC voltage sine waves have been synthesized with both programmable and pulse-driven arrays, although their accuracy is still limited by thermal oscillations due to the cryocooler piston motion.

  6. Studying Voltage Transformer Ferroresonance

    Directory of Open Access Journals (Sweden)

    Hamid Radmanesh

    2012-09-01

    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.

  7. Ultra-low Voltage CMOS Cascode Amplifier

    DEFF Research Database (Denmark)

    Lehmann, Torsten; Cassia, Marco

    2000-01-01

    In this paper, we design a folded cascode operational transconductance amplifier in a standard CMOS process, which has a measured 69 dB DC gain, a 2 MHz bandwidth and compatible input- and output voltage levels at a 1 V power supply. This is done by a novel Current Driven Bulk (CDB) technique...

  8. Optical Imaging of Neurons in the Crab Stomatogastric Ganglion with Voltage-sensitive Dyes

    Science.gov (United States)

    Stein, Wolfgang; Städele, Carola; Andras, Peter

    2011-01-01

    Voltage-sensitive dye imaging of neurons is a key methodology for the understanding of how neuronal networks are organised and how the simultaneous activity of participating neurons leads to the emergence of the integral functionality of the network. Here we present the methodology of application of this technique to identified pattern generating neurons in the crab stomatogastric ganglion. We demonstrate the loading of these neurons with the fluorescent voltage-sensitive dye Di-8-ANEPPQ and we show how to image the activity of dye loaded neurons using the MiCAM02 high speed and high resolution CCD camera imaging system. We demonstrate the analysis of the recorded imaging data using the BVAna imaging software associated with the MiCAM02 imaging system. The simultaneous voltage-sensitive dye imaging of the detailed activity of multiple neurons in the crab stomatogastric ganglion applied together with traditional electrophysiology techniques (intracellular and extracellular recordings) opens radically new opportunities for the understanding of how central pattern generator neural networks work. PMID:21490564

  9. VOLTAGE REGULATORS ASYNCHRONOUS GENERATORS

    Directory of Open Access Journals (Sweden)

    Grigorash O. V.

    2015-06-01

    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.

  10. Geomagnetism and Induced Voltage

    Science.gov (United States)

    Abdul-Razzaq, W.; Biller, R. D.

    2010-01-01

    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…

  11. 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)

    2014-07-01

    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.

  12. Diode-Assisted Buck-Boost Voltage-Source Inverters

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus;

    2009-01-01

    This paper proposes a number of diode-assisted buck-boost voltage-source inverters with a unique X-shaped diode-capacitor network inserted between the inverter circuitry and dc source for producing a voltage gain that is comparatively higher than those of other buck-boost conversion techniques...

  13. A random resistor network model of voltage trimming

    Energy Technology Data Exchange (ETDEWEB)

    Grimaldi, C [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Maeder, T [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Ryser, P [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Straessler, S [Laboratoire de Production Microtechnique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)

    2004-08-07

    In industrial applications, the controlled adjustment (trimming) of resistive elements via the application of high voltage pulses is a promising technique, with several advantages with respect to more classical approaches such as the laser cutting method. The microscopic processes governing the response to high voltage pulses depend on the nature of the resistor and on the interaction with the local environment. Here we provide a theoretical statistical description of voltage discharge effects on disordered composites by considering random resistor network models with different properties and processes due to the voltage discharge. We compare standard percolation results with biased percolation effects and provide a tentative explanation of the different scenarios observed during trimming processes.

  14. Deployment of low-voltage regulator considering existing voltage control in medium-voltage distribution systems

    Directory of Open Access Journals (Sweden)

    Hiroshi Kikusato

    2016-01-01

    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.

  15. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.

    2014-10-09

    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. Neuroprotective effect of interleukin-6 regulation of voltage-gated Na+ channels of cortical neurons is time- and dose-dependent

    Directory of Open Access Journals (Sweden)

    Wei Xia

    2015-01-01

    Full Text Available Interleukin-6 has been shown to be involved in nerve injury and nerve regeneration, but the effects of long-term administration of high concentrations of interleukin-6 on neurons in the central nervous system is poorly understood. This study investigated the effects of 24 hour exposure of interleukin-6 on cortical neurons at various concentrations (0.1, 1, 5 and 10 ng/mL and the effects of 10 ng/mL interleukin-6 exposure to cortical neurons for various durations (2, 4, 8, 24 and 48 hours by studying voltage-gated Na + channels using a patch-clamp technique. Voltage-clamp recording results demonstrated that interleukin-6 suppressed Na + currents through its receptor in a time- and dose-dependent manner, but did not alter voltage-dependent activation and inactivation. Current-clamp recording results were consistent with voltage-clamp recording results. Interleukin-6 reduced the action potential amplitude of cortical neurons, but did not change the action potential threshold. The regulation of voltage-gated Na + channels in rat cortical neurons by interleukin-6 is time- and dose-dependent.

  17. Neuroprotective effect of interleukin-6 regulation of voltage-gated Na(+) channels of cortical neurons is time- and dose-dependent.

    Science.gov (United States)

    Xia, Wei; Peng, Guo-Yi; Sheng, Jiang-Tao; Zhu, Fang-Fang; Guo, Jing-Fang; Chen, Wei-Qiang

    2015-04-01

    Interleukin-6 has been shown to be involved in nerve injury and nerve regeneration, but the effects of long-term administration of high concentrations of interleukin-6 on neurons in the central nervous system is poorly understood. This study investigated the effects of 24 hour exposure of interleukin-6 on cortical neurons at various concentrations (0.1, 1, 5 and 10 ng/mL) and the effects of 10 ng/mL interleukin-6 exposure to cortical neurons for various durations (2, 4, 8, 24 and 48 hours) by studying voltage-gated Na(+) channels using a patch-clamp technique. Voltage-clamp recording results demonstrated that interleukin-6 suppressed Na(+) currents through its receptor in a time- and dose-dependent manner, but did not alter voltage-dependent activation and inactivation. Current-clamp recording results were consistent with voltage-clamp recording results. Interleukin-6 reduced the action potential amplitude of cortical neurons, but did not change the action potential threshold. The regulation of voltage-gated Na(+) channels in rat cortical neurons by interleukin-6 is time- and dose-dependent.

  18. Increased voltage photovoltaic cell

    Science.gov (United States)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)

    1985-01-01

    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

    Science.gov (United States)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    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. Voltage-dependent K channels in protoplasts of trap-lobe cells of Dionaea muscipula.

    Science.gov (United States)

    Iijima, T; Hagiwara, S

    1987-01-01

    The outward rectification of the K+ current in mesophyll cell protoplasts from trap-lobes of Dionaea muscipula was studied with the patch-clamp technique. The rectification had instantaneous and time-dependent components. Changes in [K+]i strongly affected the conductance voltage relation of the plasma membrane while changes in [K+]o had little effect on the relation. Thus, the outward rectification depends on the membrane voltage and the concentration of intracellular K+. Corresponding single-channel activities were observed both in the intact membrane (cell-attached recording) and in excised patches. The single-channel conductance was about 3.3 pS with symmetrical solutions containing 30 mM K+.

  1. Simultaneously Propagating Voltage and Pressure Pulses in Lipid Monolayers of pork brain and synthetic lipids

    CERN Document Server

    Griesbauer, J; Wixforth, A; Schneider, M F

    2012-01-01

    Hydrated interfaces are ubiquitous in biology and appear on all length scales from ions, individual molecules to membranes and cellular networks. In vivo, they comprise a high degree of self-organization and complex entanglement, which limits their experimental accessibility by smearing out the individual phenomenology. The Langmuir technique, however, allows the examination of defined interfaces, whose controllable thermodynamic state enables one to explore the proper state diagrams. Here we demonstrate that voltage and pressure pulses simultaneously propagate along monolayers comprised of either native pork brain or synthetic lipids. The excitation of pulses is conducted by the application of small droplets of acetic acid and monitored subsequently employing timeresolved Wilhelmy plate and Kelvin probe measurements. The isothermal state diagrams of the monolayers for both lateral pressure and surface potential are experimentally recorded, enabling us to predict dynamic voltage pulse amplitudes of 0,1 to 3mV...

  2. New half-voltage and double phase operation of the Hermes III linear induction accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Mikkelson, K.A.; Westfall, R.L.; Harper-Slaboszewicz, V.J. (Sandia National Labs., Albuquerque, NM (United States)); Neely, S.M. (K-Tech Corp., Albuquerque, NM (United States))

    1991-01-01

    The standard operating mode produces bremsstrahlung with an endpoint energy of about 18 MeV. This paper describes a new mode with a 8.5 MeV endpoint energy and the same standard mode pulse characteristics achieved by operating only half of the accelerator at full charge with the advantage of minimal setup time. An extension of the new half-voltage mode is to use the other half of the accelerator for delivering a second pulse at a later time with the same technique. The double pulse mode is ideal for beam generation which requires a long interpulse time in the millisecond regime. The beam characteristics of the two half-voltage pulses are nearly identical with the nominal radiation pulse full width at half maximum of 21 ns and 10--90 risetime of 11 ns recorded by the same Compton diode radiation monitors on instruments triggered 30 ms apart.

  3. Tetrahydroacridine inhibits voltage-dependent Na+ current in guinea-pig ventricular myocytes

    Institute of Scientific and Technical Information of China (English)

    Wei WANG; Yi-ping WANG; Guo-yuan HU

    2004-01-01

    AIM: To study the effects of tetrahydroacridine (tacrine) on voltage-gated Na+ channels in cardiac tissues.METHODS: Single ventricular myocytes were enzymatically dissociated from adult guinea-pig heart. Voltagedependent Na+ current was recorded using whole cell voltage-clamp technique. RESULTS: (1) Tacrine reversibly inhibited Na+ current with an IC50 value of 120 μmol/L (95 % confidence range: 108-133 μmol/L). (2) The inhibitory effects of tacrine on Na+ current exhibited both a tonic nature and use-dependence. (3) Tacrine at 100 μmol/L caused a negative shift (about 10 mV) in the voltage-dependence of steady-state inactivation of Na+ current, and retarded its recovery from inactivation, but did not affect its activation curve. (4) Intracellular application of tacrine significantly inhibited Na+ current. CONCLUSION: In addition to blocking other voltage-gated ion channels,tacrine blocked Na+ channels in guinea-pig ventricular myocytes. Tactine acted as inactivation stabilizer of Na+channels in cardiac tissues.

  4. Mitigation of Voltage Sags in CIGRE Low Voltage Distribution Network

    DEFF Research Database (Denmark)

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

    2013-01-01

    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....

  5. Charge-pump voltage converter

    Science.gov (United States)

    Brainard, John P.; Christenson, Todd R.

    2009-11-03

    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.

  6. Energy-aware Supply Voltage and Body Biasing Voltage Scheduling Algorithm for Real-time Distributed Systems

    Institute of Scientific and Technical Information of China (English)

    SUYajuan; WEIShaojun

    2005-01-01

    Technique of energy minimization by combining Dynamic voltage scheduling (DVS) and Adaptive body biasing voltage (ABB) method for distributed realtime system at design level is proposed. First, a simplified energy optimizing model is illustrated where the supply voltage or body biasing voltage is kept as constant according to each separated frequency region, thus calculation of exceeding equation is avoided. Divergence of simplified and analytic model within 5% indicates the accuracy of this model. Based on it, the proposed approach named LEVVS (Low energy supply voltage and body biasing voltage scheduling algorithm) explores space of minimizing energy consumption by finding optimal trade-off between dynamic and static energy. The corresponding optimal supply voltage and body biasing voltage are determined by an iterative method in which the supply voltage and body biasing voltage of tasks are adjusted according to the value of energy latency differential coefficient of each task and slack time distribution of the system. Experiments show that using LEVVS approach, 51% more average energy reduction can be obtained than employing DVS method alone. Furthermore the effects of switch capacitance and global slack on the energy saving efficiency of LEVVS are investigated. The smaller the global slack or average switch capacitance is, the more the energy saving of LEVVS compared with DVS is.

  7. Transient voltage sharing in series-coupled high voltage switches

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1992-07-01

    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.

  8. Functional reconstitution of the voltage-regulated sodium channel purified from electroplax of Electrophorus electricus

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, R.L.

    1985-01-01

    The voltage-regulated NA channel is responsible for the depolarization of the excitable cell membrane during the normal action potential. This research has focused on the functional properties of the Na channel, purified from detergent extracts of electroplax membranes of the electric eel, and reconstituted into vesicles of defined phospholipid. These properties were assessed by measuring neurotoxin-modulated ion flux into the reconstituted membrane vesicles and by recording the single-channel currents of the purified channel by the patch-clamp method. The binding of tritiated tetrodotoxin (TTX) was employed as a marker for the purification of the channel. Two high-resolution fractionation steps, based on molecular charge and protein size, were used to obtain a preparation that is 80% homogeneous for a large peptide of 270,000 daltons. Radiotracer /sup 22/Na/sup +/ influx into the vesicles was stimulated by veratridine and by batrachotoxin (BTX) at concentrations of 100 ..mu..M and 5 ..mu..M, respectively. The stimulation by BTX was greater than that by veratridine, and can be as much as 16-fold over control influx levels. The stimulated influx is blocked by TTX with a K/sub i/ of 35 nM, and by local anesthetics in the normal pharmacological range. Large multilamellar vesicles prepared with a freeze-thaw step are suitable for single-channel recording techniques. When excised patches of the reconstituted membranes were voltage-clamped in the absence of activating neurotoxins, voltage-dependent single-channel currents were recorded. These displayed properties similar to those from native membranes of nerve and muscle. These results indicate that the protein purified on the basis of TTX binding is a functional Na channel possessing these functional domains: the ion-selective channel, the voltage sensors controlling activation and inactivation, and the sites of action of TTX, alkaloid neurotoxins, and local anesthetics.

  9. UNA TECNICA ESTADISTICA PARA MEDIR LA CONFLICTIVIDAD SOCIAL A TRAVES DEL REGISTRO ARQUEOLOGICO (A Statistical Technique to Measure Social Conflict through the Archaeological Record

    Directory of Open Access Journals (Sweden)

    Pascual Izquierdo-Egea

    2015-03-01

    Full Text Available Se presenta aqui una tecnica estadistica para medir la conflictividad social a traves del registro mortuorio. Nace al amparo del metodo de valoracion contextual empleado en el analisis de los ajuares funerarios desde 1993. Se trata de una herramienta fundamental para el desarrollo de la arqueologia de los fenomenos sociales, cuyos relevantes resultados empiricos avalan su trascendencia teorica. Tras proceder a su conceptualizacion en funcion de la desigualdad social y la riqueza relativa, se explican las dos clases de conflictividad social definidas: estructural o estatica y coyuntural o dinamica. Finalmente, se incluyen sus conexiones con la ley demografica de Malthus a traves de sus dos parametros: poblacion y recursos. Todo este entramado teorico se ilustra con algunas aplicaciones referidas a las civilizaciones antiguas, abarcando la protohistoria iberica, la Mesoamerica prehispanica o la Roma altoimperial. ENGLISH: A statistical technique to measure social conflict through the mortuary record is presented here. It is born under the contextual valuation method used in the analysis of grave goods since 1993. This is a fundamental tool for the development of the archaeology of social phenomena, whose relevant empirical results support its theoretical significance. After conveying its conceptualization in terms of social inequality and relative wealth, the two classes of social conflict are explained: static or structural and dynamic or conjunctural. Finally, connections with the Malthusian demographic law through its two parameters—population and resources—are included. The synthesis of these theoretical frameworks is illustrated with applications to ancient civilizations, including Iberian protohistory, prehispanic Mesoamerica, and early imperial Rome.

  10. PIP2 in pancreatic β-cells regulates voltage-gated calcium channels by a voltage-independent pathway.

    Science.gov (United States)

    de la Cruz, Lizbeth; Puente, Erika I; Reyes-Vaca, Arturo; Arenas, Isabel; Garduño, Julieta; Bravo-Martínez, Jorge; Garcia, David E

    2016-10-01

    Phosphatidylinositol-4,5-bisphosphate (PIP2) is a membrane phosphoinositide that regulates the activity of many ion channels. Influx of calcium primarily through voltage-gated calcium (CaV) channels promotes insulin secretion in pancreatic β-cells. However, whether CaV channels are regulated by PIP2, as is the case for some non-insulin-secreting cells, is unknown. The purpose of this study was to investigate whether CaV channels are regulated by PIP2 depletion in pancreatic β-cells through activation of a muscarinic pathway induced by oxotremorine methiodide (Oxo-M). CaV channel currents were recorded by the patch-clamp technique. The CaV current amplitude was reduced by activation of the muscarinic receptor 1 (M1R) in the absence of kinetic changes. The Oxo-M-induced inhibition exhibited the hallmarks of voltage-independent regulation and did not involve PKC activation. A small fraction of the Oxo-M-induced CaV inhibition was diminished by a high concentration of Ca(2+) chelator, whereas ≥50% of this inhibition was prevented by diC8-PIP2 dialysis. Localization of PIP2 in the plasma membrane was examined by transfecting INS-1 cells with PH-PLCδ1, which revealed a close temporal association between PIP2 hydrolysis and CaV channel inhibition. Furthermore, the depletion of PIP2 by a voltage-sensitive phosphatase reduced CaV currents in a way similar to that observed following M1R activation. These results indicate that activation of the M1R pathway inhibits the CaV channel via PIP2 depletion by a Ca(2+)-dependent mechanism in pancreatic β- and INS-1 cells and thereby support the hypothesis that membrane phospholipids regulate ion channel activity by interacting with ion channels.

  11. No-Voltage Meter

    Science.gov (United States)

    1976-02-01

    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

  12. Benchmarking of Voltage Sag Generators

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2012-01-01

    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...

  13. 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

    2017-01-01

    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...

  14. Heat-pump performance: voltage dip/sag, under-voltage and over-voltage

    Directory of Open Access Journals (Sweden)

    William J.B. Heffernan

    2014-12-01

    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.

  15. Effect of state feedback coupling on the transient performance of voltage source inverters with LC filter

    DEFF Research Database (Denmark)

    Federico, de Bosio; Pastorelli, Michele; Antonio DeSouza Ribeiro, Luiz

    2016-01-01

    State feedback coupling between the capacitor voltage and inductor current deteriorates notably the performance during transients of voltage and current regulators in stand-alone systems based on voltage source inverters. A decoupling technique is proposed, considering the limitations introduced ...... by system delays. Laboratory experiments were executed in compliance with the normative for Uninterruptible Power Supply systems to prove the developed analysis....

  16. Voltage Swells Improvement in Low Voltage Network Using Dynamic Voltage Restorer

    Directory of Open Access Journals (Sweden)

    R. Omar

    2011-01-01

    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.

  17. Isomerically Pure Tetramethylrhodamine Voltage Reporters.

    Science.gov (United States)

    Deal, Parker E; Kulkarni, Rishikesh U; Al-Abdullatif, Sarah H; Miller, Evan W

    2016-07-27

    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.

  18. Infrared absorption of methanol-water clusters (CH3OH)n(H2O), n = 1-4, recorded with the VUV-ionization/IR-depletion technique

    Science.gov (United States)

    Lee, Yu-Fang; Kelterer, Anne-Marie; Matisz, Gergely; Kunsági-Máté, Sándor; Chung, Chao-Yu; Lee, Yuan-Pern

    2017-04-01

    We recorded infrared (IR) spectra in the CH- and OH-stretching regions of size-selected clusters of methanol (M) with one water molecule (W), represented as MnW, n = 1-4, in a pulsed supersonic jet using the photoionization/IR-depletion technique. Vacuum ultraviolet emission at 118 nm served as the source of ionization in a time-of-flight mass spectrometer to detect clusters MnW as protonated forms Mn-1WH+. The variations in intensities of Mn-1WH+ were monitored as the wavelength of the IR laser light was tuned across the range 2700-3800 cm-1. IR spectra of size-selected clusters were obtained on processing of the observed action spectra of the related cluster-ions according to a mechanism that takes into account the production and loss of each cluster due to IR photodissociation. Spectra of methanol-water clusters in the OH region show significant variations as the number of methanol molecules increases, whereas those in the CH region are similar for all clusters. Scaled harmonic vibrational wavenumbers and relative IR intensities predicted with the M06-2X/aug-cc-pVTZ method for the methanol-water clusters are consistent with our experimental results. For dimers, absorption bands of a structure WM with H2O as a hydrogen-bond donor were observed at 3570, 3682, and 3722 cm-1, whereas weak bands of MW with methanol as a hydrogen-bond donor were observed at 3611 and 3753 cm-1. For M2W, the free OH band of H2O was observed at 3721 cm-1, whereas a broad feature was deconvoluted to three bands near 3425, 3472, and 3536 cm-1, corresponding to the three hydrogen-bonded OH-stretching modes in a cyclic structure. For M3W, the free OH shifted to 3715 cm-1, and the hydrogen-bonded OH-stretching bands became much broader, with a weak feature near 3179 cm-1 corresponding to the symmetric OH-stretching mode of a cyclic structure. For M4W, the observed spectrum agrees unsatisfactorily with predictions for the most stable cyclic structure, indicating significant contributions from

  19. Application of Partial Discharge Detection Technique in AC Voltage Withstand Test of HV Cable%局放测试技术在高压电缆交流耐压试验中的应用

    Institute of Scientific and Technical Information of China (English)

    罗容波; 詹清华; 王岩

    2013-01-01

      针对交流耐压试验方法在发现电缆缺陷上的不足,提出在高压电缆交流耐压试验中外接局放监视仪来避免耐压试验对电缆造成损伤。通过建立仿真电路和搭建实验室模型,研究了现场干扰信号与电缆自身局放信号的时域、频域、波形和极性的特征,总结出一套适用于高压电缆现场局放测试的方法。应用该方法对新敷设的110 kV高压电缆进行检测,发现了高压电缆终端的缺陷,证实了此测试方法的有效性。%  In view of the shortcomings of AC withstand voltage test method in discovering the faults of HV cable, a partial discharge monitoring instrument is external connected with AC withstand voltage test to avoid the damage of cable. The time domain, frequency domain, waveform and polarity characteristics of the interference signal and the signal of cable were studied by simulation and experimental research, and a method suitable for the partial discharge test of HV cable was summarized. The termination fault of a new HV cable was found by applying the method, which confirms the validity of the method.

  20. Application of Current Sharing Technique in Low Voltage High Current Switching Power Supply%均流技术在低压大电流开关电源中的应用

    Institute of Scientific and Technical Information of China (English)

    王晓琴

    2016-01-01

    In the design of low-voltage high-current switching power supply, due to the relatively small output voltage, and large output current, in order to solve this problem, heterogeneous parallel is usually needed. In multiphase crisscross DC/DC converter, there is a problem of non-uniform current distribution, which will cause too large current in one phase causing damage and too small current in another phase failing to work normally. Aiming at this problem, the paper proposes using the HIP6303 HIP6602B and automatic flow technology, and the flow method is introduced in detail. Through theory and experiment, its current sharing effect is verified, thus the feasibility of the scheme is obtained.%在低压大电流开关电源的设计中,由于输出电压比较小,而输出电流又较大,为了解决此问题,通常需要多相并联,在多相交错的DC/DC变换器中,存在着电流分配不均匀的问题,电流分配不均匀,就会使得某相电流过大而损坏,某相电流过小而不能正常的工作。针对这个问题,文章提出了用HIP6303和HIP6602B进行自动均流的技术,并对这种均流方法进行了详细的论述,通过理论和实验,验证了其均流的效果,由此得出该方案的可行性。

  1. 低管电压联合迭代重建技术在脑血管CT成像中的应用%An application of low tube voltage in combination with simultaneous iterative reconstruction technique in cerebrovascular CT imaging

    Institute of Scientific and Technical Information of China (English)

    曹国全; 唐坤; 潘克华; 邰云鹏; 陈晓; 吴恩福; 王镇章

    2014-01-01

    nique on the image quality and radiation dose in cerebrovascular imaging and determine the optimum tube volt-age and iterative reconstruction parameters.Methods: A home-made blood vessel of brain was constructed using an ATOM 701-D adult male phantom head and iodine-water mixture contrast agent. A 320-row volume CT was used to scan the home-made brain at tube voltages of 80, 100 and 120 kV in combination with off, mild, standard and strong iterative reconstruction levels (12 protocols in total), respectively. Tube current and other parameters were not changed during scanning. CT value of the transverse blood vessels and its corresponding noise, CT value of brain tissue around blood vessels and its corresponding noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were obtained. One-Way ANOVA analysis was applied to investigate the impacts of different tube voltages and simultaneous iterative reconstruction levels to image quality.Results: Compared with group 120 kV, the CTDIvol, dose length product (DLP), effective dose (ED) of group 100 kV and 80 kV reduced 39.29%, 39.52%, 39.42% and 66.88%, 67.02%, 67.31% respectively. When the tube voltage was kept constant, blood ves-sel noise, noise of brain surrounding blood vessels, SNR and CNR showed statistical difference (P0.05) at different iterative reconstruction levels. When iterative reconstruction level was not changed and tube voltage was varied,both CT values of blood vessel and blood vessel noise exhibited statistical difference (P0.05), and noise of brain tissue around blood vessels showed statistical difference (P0.05) at standard or strong levels.Conclusion: High-quality cerebrovascular imaging can be acquired at a tube voltage of 100 kV in combination with a standard or strong level of iterative reconstruction algorithm.%目的:探讨脑血管CT成像中管电压联合迭代重建与图像质量及剂量间的关系,以确定最优管电压和迭代重建的参数。方法:利用ATOM701

  2. Voltage-induced reduction of graphene oxide

    Science.gov (United States)

    Faucett, Austin C.

    Graphene Oxide (GO) is being widely researched as a precursor for the mass production of graphene, and as a versatile material in its own right for flexible electronics, chemical sensors, and energy harvesting applications. Reduction of GO, an electrically insulating material, into reduced graphene oxide (rGO) restores electrical conductivity via removal of oxygen-containing functional groups. Here, a reduction method using an applied electrical bias, known as voltage-induced reduction, is explored. Voltage-induced reduction can be performed under ambient conditions and avoids the use of hazardous chemicals or high temperatures common with standard methods, but little is known about the reduction mechanisms and the quality of rGO produced with this method. This work performs extensive structural and electrical characterization of voltage-reduced GO (V-rGO) and shows that it is competitive with standard methods. Beyond its potential use as a facile and eco-friendly processing approach, V-rGO reduction also offers record high-resolution patterning capabilities. In this work, the spatial resolution limits of voltage-induced reduction, performed using a conductive atomic force microscope probe, are explored. It is shown that arbitrary V-rGO conductive features can be patterned into insulating GO with nanoscale resolution. The localization of voltage-induced reduction to length scales < 10 nm allows studies of reduction reaction kinetics, using electrical current obtained in-situ, with statistical robustness. Methods for patterning V-rGO nanoribbons are then developed. After presenting sub-10nm patterning of V-rGO nanoribbons in GO single sheets and films, the performance of V-rGO nanoribbon field effect transistors (FETs) are demonstrated. Preliminary measurements show an increase in electrical current on/off ratios as compared to large-area rGO FETs, indicating transport gap modulation that is possibly due to quantum confinement effects.

  3. Imaging fast calcium currents beyond the limitations of electrode techniques.

    Science.gov (United States)

    Jaafari, Nadia; De Waard, Michel; Canepari, Marco

    2014-09-16

    The current understanding of Ca(2+) channel function is derived from the use of the patch-clamp technique. In particular, the measurement of fast cellular Ca(2+) currents is routinely achieved using whole-cell voltage-clamp recordings. However, this experimental approach is not applicable to the study of local native Ca(2+) channels during physiological changes of membrane potential in complex cells, since the voltage-clamp configuration constrains the membrane potential to a given value. Here, we report for the first time to our knowledge that Ca(2+) currents from individual cells can be quantitatively measured beyond the limitations of the voltage-clamp approach using fast Ca(2+) imaging with low-affinity indicators. The optical measurement of the Ca(2+) current was correlated with the membrane potential, simultaneously measured with a voltage-sensitive dye to investigate the activation of Ca(2+) channels along the apical dendrite of the CA1 hippocampal pyramidal neuron during the back-propagation of an action potential. To validate the method, we analyzed the voltage dependence of high- and low-voltage-gated Ca(2+) channels. In particular, we measured the Ca(2+) current component mediated by T-type channels, and we investigated the mechanisms of recovery from inactivation of these channels. This method is expected to become a reference approach to investigate Ca(2+) channels in their native physiological environment.

  4. Methods, systems and apparatus for controlling third harmonic voltage when operating a multi-space machine in an overmodulation region

    Energy Technology Data Exchange (ETDEWEB)

    Perisic, Milun; Kinoshita, Michael H; Ranson, Ray M; Gallegos-Lopez, Gabriel

    2014-06-03

    Methods, system and apparatus are provided for controlling third harmonic voltages when operating a multi-phase machine in an overmodulation region. The multi-phase machine can be, for example, a five-phase machine in a vector controlled motor drive system that includes a five-phase PWM controlled inverter module that drives the five-phase machine. Techniques for overmodulating a reference voltage vector are provided. For example, when the reference voltage vector is determined to be within the overmodulation region, an angle of the reference voltage vector can be modified to generate a reference voltage overmodulation control angle, and a magnitude of the reference voltage vector can be modified, based on the reference voltage overmodulation control angle, to generate a modified magnitude of the reference voltage vector. By modifying the reference voltage vector, voltage command signals that control a five-phase inverter module can be optimized to increase output voltages generated by the five-phase inverter module.

  5. Voltage Dependence of Supercapacitor Capacitance

    Directory of Open Access Journals (Sweden)

    Szewczyk Arkadiusz

    2016-09-01

    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.

  6. A comparative study of the action of tolperisone on seven different voltage dependent sodium channel isoforms.

    Science.gov (United States)

    Hofer, Doris; Lohberger, Birgit; Steinecker, Bibiane; Schmidt, Kurt; Quasthoff, Stefan; Schreibmayer, Wolfgang

    2006-05-24

    The specific, acute interaction of tolperisone, an agent used as a muscle relaxant and for the treatment of chronic pain conditions, with the Na(v1.2), Na(v1.3), Na(v1.4), Na(v1.5), Na(v1.6), Na(v1.7), and Na(v1.8) isoforms of voltage dependent sodium channels was investigated and compared to that of lidocaine. Voltage dependent sodium channels were expressed in the Xenopus laevis oocyte expression system and sodium currents were recorded with the two electrode voltage clamp technique. Cumulative dose response relations revealed marked differences in IC(50) values between the two drugs on identical isoforms, as well as between isoforms. A detailed kinetic analysis uncovered that tolperisone as well as lidocaine exhibited their blocking action not only via state dependent association/dissociation with voltage dependent sodium channels, but a considerable fraction of inhibition is tonic, i.e. permanent and basic in nature. Voltage dependent activation was affected to a minor extent only. A shift in steady-state inactivation to more negative potentials could be observed for most drug/isoform combinations. The contribution of this shift to overall block was, however, small at drug concentrations resulting in considerable overall block. Recovery from inactivation was affected notably by both drugs. Lidocaine application led to a pronounced prolongation of the time constant of the fast recovery process for the Na(v1.3), Na(v1.5), and Na(v1.7) isoforms, indicating common structural properties in the local anesthetic receptor site of these three proteins. Interestingly, this characteristic drug action was not observed for tolperisone.

  7. Mechanism of electromechanical coupling in voltage-gated potassium channels

    Directory of Open Access Journals (Sweden)

    Rikard eBlunck

    2012-09-01

    Full Text Available Voltage-gated ion channels play a central role in the generation of action potentials in the nervous system. They are selective for one type of ion – sodium, calcium or potassium. Voltage-gated ion channels are composed of a central pore that allows ions to pass through the membrane and four peripheral voltage sensing domains that respond to changes in the membrane potential. Upon depolarization, voltage sensors in voltage-gated potassium channels (Kv undergo conformational changes driven by positive charges in the S4 segment and aided by pairwise electrostatic interactions with the surrounding voltage sensor. Structure-function relations of Kv channels have been investigated in detail, and the resulting models on the movement of the voltage sensors now converge to a consensus; the S4 segment undergoes a combined movement of rotation, tilt and vertical displacement in order to bring 3-4 e+ each through the electric field focused in this region. Nevertheless, the mechanism by which the voltage sensor movement leads to pore opening, the electromechanical coupling, is still not fully understood. Thus, recently, electromechanical coupling in different Kv channels has been investigated with a multitude of techniques including electrophysiology, 3D crystal structures, fluorescence spectroscopy and molecular dynamics simulations. Evidently, the S4-S5 linker, the covalent link between the voltage sensor and pore, plays a crucial role. The linker transfers the energy from the voltage sensor movement to the pore domain via an interaction with the S6 C-termini, which are pulled open during gating. In addition, other contact regions have been proposed. This review aims to provide (i an in-depth comparison of the molecular mechanisms of electromechanical coupling in different Kv channels; (ii insight as to how the voltage sensor and pore domain influence one another; and (iii theoretical predictions on the movement of the cytosolic face of the KV channels

  8. Neuroprotective effect of interleukin-6 regulation of voltage-gated Na+ channels of cortical neurons is time- and dose-dependent

    Institute of Scientific and Technical Information of China (English)

    Wei Xia; Guo-yi Peng; Jiang-tao Sheng; Fang-fang Zhu; Jing-fang Guo; Wei-qiang Chen

    2015-01-01

    Interleukin-6 has been shown to be involved in nerve injury and nerve regeneration, but the effects of long-term administration of high concentrations of interleukin-6 on neurons in the central nervous system is poorly understood. This study investigated the effects of 24 hour expo-sure of interleukin-6 on cortical neurons at various concentrations (0.1, 1, 5 and 10 ng/mL) and the effects of 10 ng/mL interleukin-6 exposure to cortical neurons for various durations (2, 4, 8, 24 and 48 hours) by studying voltage-gated Na+ channels using a patch-clamp technique. Volt-age-clamp recording results demonstrated that interleukin-6 suppressed Na+ currents through its receptor in a time- and dose-dependent manner, but did not alter voltage-dependent activation and inactivation. Current-clamp recording results were consistent with voltage-clamp recording results. Interleukin-6 reduced the action potential amplitude of cortical neurons, but did not change the action potential threshold. The regulation of voltage-gated Na+channels in rat corti-cal neurons by interleukin-6 is time- and dose-dependent.

  9. CMOS voltage references an analytical and practical perspective

    CERN Document Server

    Kok, Chi-Wah

    2013-01-01

    A practical overview of CMOS circuit design, this book covers the technology, analysis, and design techniques of voltage reference circuits.  The design requirements covered follow modern CMOS processes, with an emphasis on low power, low voltage, and low temperature coefficient voltage reference design. Dedicating a chapter to each stage of the design process, the authors have organized the content to give readers the tools they need to implement the technologies themselves. Readers will gain an understanding of device characteristics, the practical considerations behind circuit topology,

  10. Voltage-sensitive rhodol with enhanced two-photon brightness.

    Science.gov (United States)

    Kulkarni, Rishikesh U; Kramer, Daniel J; Pourmandi, Narges; Karbasi, Kaveh; Bateup, Helen S; Miller, Evan W

    2017-03-14

    We have designed, synthesized, and applied a rhodol-based chromophore to a molecular wire-based platform for voltage sensing to achieve fast, sensitive, and bright voltage sensing using two-photon (2P) illumination. Rhodol VoltageFluor-5 (RVF5) is a voltage-sensitive dye with improved 2P cross-section for use in thick tissue or brain samples. RVF5 features a dichlororhodol core with pyrrolidyl substitution at the nitrogen center. In mammalian cells under one-photon (1P) illumination, RVF5 demonstrates high voltage sensitivity (28% ΔF/F per 100 mV) and improved photostability relative to first-generation voltage sensors. This photostability enables multisite optical recordings from neurons lacking tuberous sclerosis complex 1, Tsc1, in a mouse model of genetic epilepsy. Using RVF5, we show that Tsc1 KO neurons exhibit increased activity relative to wild-type neurons and additionally show that the proportion of active neurons in the network increases with the loss of Tsc1. The high photostability and voltage sensitivity of RVF5 is recapitulated under 2P illumination. Finally, the ability to chemically tune the 2P absorption profile through the use of rhodol scaffolds affords the unique opportunity to image neuronal voltage changes in acutely prepared mouse brain slices using 2P illumination. Stimulation of the mouse hippocampus evoked spiking activity that was readily discerned with bath-applied RVF5, demonstrating the utility of RVF5 and molecular wire-based voltage sensors with 2P-optimized fluorophores for imaging voltage in intact brain tissue.

  11. Structural integrity--Searching the key factor to suppress the voltage fade of Li-rich layered cathode materials through 3D X-ray imaging and spectroscopy techniques

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yahong; Hu, Enyuan; Yang, Feifei; Corbett, Jeff; Sun, Zhihong; Lyu, Yingchun; Yu, Xiqian; Liu, Yijin; Yang, Xiao-Qing; Li, Hong (BNL); (SLAC); (UCSF); (Donghua); (Chinese Aca. Sci.)

    2016-10-24

    Li-rich layered materials are important cathode compounds used in commercial lithium ion batteries, which, however, suffers from some drawbacks including the so-called voltage fade upon electrochemical cycling. Here, our study employs novel transmission X-ray microscopy to investigate the electrochemical reaction induced morphological and chemical changes in the Li-rich Li2Ru0.5Mn0.5O3 cathode particles at the meso to nano scale. We performed combined X-ray spectroscopy, diffraction and microscopy experiments to systematically study this cathode material's evolution upon cycling as well as to establish a comprehensive understanding of the structural origin of capacity fade through 2D and 3D fine length scale morphology and heterogeneity change of this material. This work suggests that atomic manipulation (e.g. doping, substitution etc.) or nano engineering (e.g. nano-sizing, heterogeneous structure) are important strategies to mitigate the internal strain and defects induced by extensive lithium insertion/extraction. It also shows that maintaining the structural integrity is the key in designing and synthesizing lithium-rich layered materials with better cycle stability.

  12. Adaptive Voltage Management Enabling Energy Efficiency in Nanoscale Integrated Circuits

    Science.gov (United States)

    Shapiro, Alexander E.

    Battery powered devices emphasize energy efficiency in modern sub-22 nm CMOS microprocessors rendering classic power reduction solutions not sufficient. Classical solutions that reduce power consumption in high performance integrated circuits are superseded with novel and enhanced power reduction techniques to enable the greater energy efficiency desired in modern microprocessors and emerging mobile platforms. Dynamic power consumption is reduced by operating over a wide range of supply voltages. This region of operation is enabled by a high speed and power efficient level shifter which translates low voltage digital signals to higher voltages (and vice versa), a key component that enables communication among circuits operating at different voltage levels. Additionally, optimizing the wide supply voltage range of signals propagating across long interconnect enables greater energy savings. A closed-form delay model supporting wide voltage range is developed to enable this capability. The model supports an ultra-wide voltage range from nominal voltages to subthreshold voltages, and a wide range of repeater sizes. To mitigate the drawback of lower operating speed at reduced supply voltages, the high performance exhibited by MOS current mode logic technology is exploited. High performance and energy efficient circuits are enabled by combining this logic style with power efficient near threshold circuits. Many-core systems that operate at high frequencies and process highly parallel workloads benefit from this combination of MCML with NTC. Due to aggressive scaling, static power consumption can in some cases overshadow dynamic power. Techniques to lower leakage power have therefore become an important objective in modern microprocessors. To address this issue, an adaptive power gating technique is proposed. This technique utilizes high levels of granularity to save additional leakage power when a circuit is active as opposed to standard power gating that saves static

  13. Voltage Stability Evaluation Incorporating Wind Power Intermittency

    Institute of Scientific and Technical Information of China (English)

    Libao SHI; Yang ZHAO; Yixin NI; Liangzhong YAO; Masoud BAZARGAN

    2013-01-01

    A simulation framework is proposed to evaluate the voltage stability of power systems incorporating wind power intermittency.Firstly,the power output modelings of three types of wind turbines are discussed.Secondly,the Jensen model is employed to simulate the wind farm with the wake effect.The Monte Carlo based technique is used to conduct the voltage stability evaluation incorporating the randomness of the wind speed based on the Weibull probability distribution.Thirdly,the relative sensitivity index (RSI) is calculated to identify weak buses during analysis.Finally,case studies with different simulation scenarios are carried out.Some statistical results involving weakness probability,expected value and variance of RSI as well as preliminary conclusions are drawn based on numerical simulation results.

  14. On-chip High-Voltage Generator Design

    CERN Document Server

    Tanzawa, Toru

    2013-01-01

    This book describes high-voltage generator design with switched-capacitor multiplier techniques.  The author provides various design techniques for switched-capacitor on-chip high-voltage generators, including charge pump circuits, regulators, level shifters, references, and oscillators.  Readers will see these techniques applied to system design in order to address the challenge of how the on-chip high-voltage generator is designed for Flash memories, LCD drivers, and other semiconductor devices to optimize the entire circuit area and power efficiency with a low voltage supply, while minimizing the cost.   ·         Shows readers how to design charge pump circuits with lower voltage operation, higher power efficiency, and smaller circuit area; ·         Describes comprehensive circuits and systems design of on-chip high-voltage generators; ·         Covers all the component circuit blocks, including charge pumps, pump regulators, level shifters, oscillators, and references.

  15. A Low-Voltage CMOS Buffer for RF Applications Based on a Fully-Differential Voltage-Combiner

    OpenAIRE

    Abdollahvand, S.; Santos-Tavares, R.; Goes, João

    2013-01-01

    Part 20: Electronics: RF Applications; International audience; This paper presents a new CMOS buffer circuit topology for radio-frequency (RF) applications based on a fully-differential voltage-combiner circuit, capable of operating at low-voltage. The proposed circuit uses a combination of common-source (CS) and common-drain (CD) devices. The simulation results show good levels of linearity and bandwidth. To improve total harmonic distortion (THD) a source degeneration technique is used. The...

  16. Estimation of line flows and bus voltages using decision trees

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.C.; Hsu, Y.Y. (National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Electrical Engineering)

    1994-08-01

    A machine learning method called the ID3 (Interative Dichotomizer 3) approach is presented for the estimation of line flows and bus voltages following an outage event. A decision tree which is capable of generating the desired line flows and bus voltages are created using the training patterns which are compiled from the historical operating records of Taiwan power system. The established decision tree contains the knowledge which is essential for line flow and bus voltage prediction. Thus, it can be applied to estimate line flows and bus voltages of a system in an efficient manner. The effectiveness of the proposed ID3 approach is demonstrated by security assessment of Taiwan power system which contains 170 buses and 207 lines.

  17. 适应实际电网阻抗特性的 DFIG 不平衡电压解耦补偿技术%An Unbalanced Voltage Decoupling Compensation Technique for DFIG Adaptive to Grid Impedance

    Institute of Scientific and Technical Information of China (English)

    年珩; 王涛; 程鹏

    2015-01-01

    A compensation strategy using doubly-fed induction generator (DFIG) to rebalance the voltage at point of common coupling (PCC) is proposed.By tuning the decoupling controller based on the estimated network impedance,d-q components of the negative sequence voltage at PCC is decoupling controlled,which gives the DFIG system good stability and fast response under arbitrary network impedance ratio.The design principles of the proposed strategy is introduced in detail,then the closed loop transfer function of a DFIG system utilizing the proposed strategy is derived,and the loci of the closed loop poles with varying network impedance ratio are plotted,with which the impact of the network impedance estimation error on the system performance is analyzed.Simulation model is built to compare the control performance of the traditional non-decoupling strategy and the proposed decoupling strategy.Finally,experiments on a prototype validate the effectiveness and superiority of the proposed strategy.%提出了一种利用双馈感应发电机(DFIG)补偿公共连接点(PCC)不平衡电压的方法。在DFIG 负序数学模型基础上,使用基于电网阻抗观测的解耦控制器实现 DFIG 对 PCC 负序电压交、直轴分量的解耦控制,确保 DFIG 系统在任意电网阻抗比下具有优良的负序电压补偿性能。详细介绍了该方法的设计思路,推导了使用该方法的 DFIG 系统的闭环传递函数,通过研究电网阻抗比变化时系统闭环极点的轨迹分析了所提不平衡补偿方法的稳定运行能力,并分析了所提方法对电网阻抗动态变化及阻抗估计误差的适应能力。搭建了 Simulink 仿真模型,对比分析了所提解耦补偿方法与传统不解耦补偿方法的控制性能。最后,搭建了单机实验平台,实验结果证明了所提补偿方法的有效性和相比不解耦补偿方法的优越性。

  18. Records Management

    Data.gov (United States)

    U.S. Environmental Protection Agency — All Federal Agencies are required to prescribe an appropriate records maintenance program so that complete records are filed or otherwise preserved, records can be...

  19. A comparative study for detection and measurement of voltage disturbance in online condition

    Directory of Open Access Journals (Sweden)

    Vijay Gajanan Neve

    2015-05-01

    Full Text Available Voltage disturbance is the most important power quality problem faced by many industrial customers. It includes voltage sag, swell, spikes and harmonics. Real time detection of these voltage disturbances posed various problems. This paper compares the various methods of detection of voltage sag and swells in real time on the basis of detection time, magnitude, effect of windowing and effect of sampling frequencies. The RMS, Peak, Fourier transform and Missing Voltage algorithm are introduced and discussed in them for real time implementation. Comparative analysis reveals that quantification of voltage sag and swell is possible using these measurements. The main focus is given on to these points and all the voltage sag and swell detection technique tested online with the help of advantech card data acquisition. The voltage sag and swell events are generated by using practical experimentation in laboratory.

  20. Dynamic voltage regulation and power export in a distribution system using distributed generation

    Institute of Scientific and Technical Information of China (English)

    Aamir HANIF; Muhammad Ahmed CHOUDHRY

    2009-01-01

    The major aim of power quality (PQ) enhancing techniques is to maintain a specified voltage magnitude at a desired frequency for sensitive loads irrespective of faults on the power distribution network. The dynamic voltage restorer (DVR) is a device used to mitigate voltage sags to regulate load voltage. This paper presents a mathematical model for leading series voltage injection to mitigate sags thereby achieving the improvement of the utility power factor as well as power sharing between the DVR and utility. The power sharing will be as per requirement to compensate the sags considering the available distributed generation (DG). The approach of mitigating voltage sags using the concept of leading series voltage injection is suitable for those locations where phase shift in the voltage will not cause any problem. The MATLAB/SIMULINK SimPowerSystem toolbox has been used to obtain simulation results to verify the proposed mathematical model.

  1. Role of low voltage activated calcium channels in neuritogenesis and active migration of embryonic neural progenitor cells.

    Science.gov (United States)

    Louhivuori, Lauri M; Louhivuori, Verna; Wigren, Henna-Kaisa; Hakala, Elina; Jansson, Linda C; Nordström, Tommy; Castrén, Maija L; Akerman, Karl E

    2013-04-15

    The central role of calcium influx and electrical activity in embryonic development raises important questions about the role and regulation of voltage-dependent calcium influx. Using cultured neural progenitor cell (NPC) preparations, we recorded barium currents through voltage-activated channels using the whole-cell configuration of the patch-clamp technique and monitored intracellular free calcium concentrations with Fura-2 digital imaging. We found that NPCs as well as expressing high-voltage-activated (HVA) calcium channels express functional low-threshold voltage-dependent calcium channels in the very early stages of differentiation (5 h to 1 day). The size of the currents recorded at -50 versus -20 mV after 1 day in differentiation was dependent on the nature of the charge carrier. Peak currents measured at -20 mV in the presence 10 mM Ca2+ instead of 10 mM Ba2+ had a tendency to be smaller, whereas the nature of the divalent species did not influence the amplitude measured at -50 mV. The T-type channel blockers mibefradil and NNC 55-0396 significantly reduced the calcium responses elicited by depolarizing with extracellular potassium, while the overall effect of the HVA calcium channel blockers was small at differentiation day 1. At differentiation day 20, the calcium responses were effectively blocked by nifedipine. Time-lapse imaging of differentiating neurospheres cultured in the presence of low-voltage-activated (LVA) blockers showed a significant decrease in the number of active migrating neuron-like cells and neurite extensions. Together, these data provide evidence that LVA calcium channels are involved in the physiology of differentiating and migrating NPCs.

  2. Novel Low Loss Active Voltage Clamp Circuit for Series Connection of RCGCT thyristors

    Science.gov (United States)

    Ito, Hiroshi; Suzuki, Akihiro; Iwata, Akihiko

    This paper describes novel low loss active voltage clamp circuits for the series connection of RCGCT thyristors. For high voltage converters the series connection of power semiconductor devices is an essential technique for direct switching of high voltages. Several protection circuits have been applied to the series connection of RCGCT thyristors such as CRD snubber circuits which suppress over-voltages across RCGCT thyristors, and voltage balancing resistors to equalize voltage sharing in steady states. However, significant losses in these protection circuits lower the converter’s efficiency. We propose novel low-loss protection circuits, which have active voltage clamp snubber circuits and static voltage balancing circuits. The clamp capacitor voltage of the active voltage clamp snubber circuits are designed to be higher than the equally divided DC-Link voltage. This method can reduce the loss of the clamp circuit to no more than 1/10 of that of the conventional CRD snubber. Also the static voltage balancing circuits compensate for the voltage imbalance generated by the difference in the leakage current between the series connection RCGCT thyristors.

  3. Voltage Sensors Monitor Harmful Static

    Science.gov (United States)

    2009-01-01

    A tiny sensor, small enough to be worn on clothing, now monitors voltage changes near sensitive instruments after being created to alert Agency workers to dangerous static buildup near fuel operations and avionics. San Diego s Quasar Federal Systems received a Small Business Innovation Research (SBIR) contract from Kennedy Space Center to develop its remote voltage sensor (RVS), a dime-sized electrometer designed to measure triboelectric changes in the environment. One of the unique qualities of the RVS is that it can detect static at greater distances than previous devices, measuring voltage changes from a few centimeters to a few meters away, due to its much-improved sensitivity.

  4. Low Voltage Power Supply Incorporating Ceramic Transformer

    CERN Document Server

    Imori, M

    2007-01-01

    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. Modular High Voltage Power Supply

    Energy Technology Data Exchange (ETDEWEB)

    Newell, Matthew R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-18

    The goal of this project is to develop a modular high voltage power supply that will meet the needs of safeguards applications and provide a modular plug and play supply for use with standard electronic racks.

  6. Power converters for medium voltage networks

    CERN Document Server

    Islam, Md Rabiul; Zhu, Jianguo

    2014-01-01

    This book examines a number of topics, mainly in connection with advances in semiconductor devices and magnetic materials and developments in medium and large-scale renewable power plant technologies, grid integration techniques and new converter topologies, including advanced digital control systems for medium-voltage networks. The book's individual chapters provide an extensive compilation of fundamental theories and in-depth information on current research and development trends, while also exploring new approaches to overcoming some critical limitations of conventional grid integration te

  7. Reliability criteria for voltage stability

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Carson W.; Silverstein, Brian L. [Bonneville Power Administration, Portland, OR (United States)

    1994-12-31

    In face of costs pressures, there is need to allocate scare resources more effectively in order to achieve voltage stability. This naturally leads to development of probabilistic criteria and notions of rick management. In this paper it is presented a discussion about criteria for long term voltage stability limited to the case in which the time frames are topically several minutes. (author) 14 refs., 1 fig.

  8. A matter of quantum voltages.

    Science.gov (United States)

    Sellner, Bernhard; Kathmann, Shawn M

    2014-11-14

    Voltages inside matter are relevant to crystallization, materials science, biology, catalysis, and aqueous chemistry. The variation of voltages in matter can be measured by experiment, however, modern supercomputers allow the calculation of accurate quantum voltages with spatial resolutions of bulk systems well beyond what can currently be measured provided a sufficient level of theory is employed. Of particular interest is the Mean Inner Potential (V(o))--the spatial average of these quantum voltages referenced to the vacuum. Here we establish a protocol to reliably evaluate V(o) from quantum calculations. Voltages are very sensitive to the distribution of electrons and provide metrics to understand interactions in condensed phases. In the present study, we find excellent agreement with measurements of V(o) for vitrified water and salt crystals and demonstrate the impact of covalent and ionic bonding as well as intermolecular/atomic interactions. Certain aspects in this regard are highlighted making use of simple model systems/approximations. Furthermore, we predict V(o) as well as the fluctuations of these voltages in aqueous NaCl electrolytes and characterize the changes in their behavior as the resolution increases below the size of atoms.

  9. A technique for recording polycrystalline structure and orientation during in situ deformation cycles of rock analogues using an automated fabric analyser.

    Science.gov (United States)

    Peternell, M; Russell-Head, D S; Wilson, C J L

    2011-05-01

    Two in situ plane-strain deformation experiments on norcamphor and natural ice using synchronous recording of crystal c-axis orientations have been performed with an automated fabric analyser and a newly developed sample press and deformation stage. Without interrupting the deformation experiment, c-axis orientations are determined for each pixel in a 5 × 5 mm sample area at a spatial resolution of 5 μm/pixel. In the case of norcamphor, changes in microstructures and associated crystallographic information, at a strain rate of ∼2 × 10(-5) s(-1), were recorded for the first time during a complete in situ deformation-cycle experiment that consisted of an annealing, deformation and post-deformation annealing path. In the case of natural ice, slower external strain rates (∼1 × 10(-6) s(-1)) enabled the investigation of small changes in the polycrystal aggregate's crystallography and microstructure for small amounts of strain. The technical setup and first results from the experiments are presented. © 2010 The Authors Journal of Microscopy © 2010 Royal Microscopical Society.

  10. High perfomance selectable value transportable high dc Voltage standard

    CERN Document Server

    Galliana, Flavio; Tet, Luca Roncaglione

    2016-01-01

    At National Institute of Metrological Research (INRIM), a selectable-value Transportable High dcVoltage Standard (THVS) operating in the range from 10 V to 100 V in steps of 10 V, was developed. This Standard was built to cover the lack of high level dc Voltage Standards at voltages higher than 10 V to employ as laboratory (local) or travelling Standards for Inter-Laboratory Comparisons (ILCs). A ground-mobile electronic technique was used to enhance the accuracy of the THVS at the higher values. The THVS shows better noise, better short-mid-term stability than top level dc Voltage and multifunction calibrators (MFCs) and better suitability and insensibility to be transported than these instruments. The project is extensible to 1000 V.

  11. Contribution of variable-speed wind turbines to voltage control

    Energy Technology Data Exchange (ETDEWEB)

    Ledesma, P.; Usaola, J.

    2003-07-01

    Variable speed, grid connected, wind turbines open new possibilities for voltage control, because they use electronic converters, which may regulate the reactive power interchange with the grid. This paper proposes two voltage control schemes for variable speed wind turbines with double-fed induction generator. The first scheme acts on the wind-turbine power factor, while the latter acts directly on the converter current. Advantages and draw backs of both techniques are discussed. Both control techniques have been tested by simulations of a base case, which represent a synchronous generator, a wind farm and a local load, and several disturbances such as the loss of compensator capacitors. (author)

  12. VOLTAGE COMPENSATION USING ARTIFICIAL NEURAL NETWORK

    African Journals Online (AJOL)

    VOLTAGE COMPENSATION USING ARTIFICIAL NEURAL NETWORK: A CASE STUDY OF RUMUOLA DISTRIBUTION NETWORK. ... The artificial neural networks controller engaged to controlling the dynamic voltage ... Article Metrics.

  13. A Low-Voltage Electronically Tunable MOSFET-C Voltage-Mode First-Order All-Pass Filter Design

    Directory of Open Access Journals (Sweden)

    B. Metin

    2013-12-01

    Full Text Available This paper presents a simple electronically tunable voltage-mode first-order all-pass filter realization with MOSFET-C technique. In comparison to the classical MOSFET-C filter circuits that employ active elements including large number of transistors the proposed circuit is only composed of a single two n-channel MOSFET-based inverting voltage buffer, three passive components, and one NMOS-based voltage-controlled resistor, which is with advantage used to electronically control the pole frequency of the filter in range 103 kHz to 18.3 MHz. The proposed filter is also very suitable for low-voltage operation, since between its supply rails it uses only two MOSFETs. In the paper the effect of load is investigated. In addition, in order to suppress the effect of non-zero output resistance of the inverting voltage buffer, two compensation techniques are also introduced. The theoretical results are verified by SPICE simulations using PTM 90 nm level-7 CMOS process BSIM3v3 parameters, where +/- 0.45 V supply voltages are used. Moreover, the behavior of the proposed filter was also experimentally measured using readily available array transistors CD4007UB by Texas Instruments.

  14. Cell-attached recordings of responses evoked by photorelease of GABA in the immature cortical neurons

    Directory of Open Access Journals (Sweden)

    Marat eMinlebaev

    2013-05-01

    Full Text Available We present a novel non-invasive technique to measure the polarity of GABAergic responses based on cell-attached recordings of currents activated by laser-uncaging of GABA. For these recordings, a patch pipette was filled with a solution containing RuBi-GABA, and GABA was released from this complex by a laser beam conducted to the tip of the patch pipette via an optic fiber. In cell-attached recordings from neocortical and hippocampal neurons in postnatal days P2-5 rat brain slices in vitro, we found that laser-uncaging of GABA activates integral cell-attached currents mediated by tens of GABA(A channels. The initial response was inwardly directed, indicating a depolarizing response to GABA. The direction of the initial response was dependent on the pipette potential and analysis of its slope-voltage relationships revealed a depolarizing driving force of +11 mV for the currents through GABA channels. Initial depolarizing responses to GABA uncaging were inverted to hyperpolarizing in the presence of the NKCC1 blocker bumetanide. Current-voltage relationships of the currents evoked by Rubi-GABA uncaging using voltage-ramps at the peak of responses not only revealed a bumetanide-sensitive depolarizing reversal potential of the GABA(A receptor mediated responses, but also showed a strong voltage-dependent hysteresis. Upon desensitization of the uncaged-GABA response, current-voltage relationships of the currents through single GABA(A channels revealed depolarizing responses with the driving force values similar to those obtained for the initial response. Thus, cell-attached recordings of the responses evoked by local intrapipette GABA uncaging are suitable to assess the polarity of the GABA(A-Rs mediated signals in small cell compartments.

  15. Voltage stability analysis in the new deregulated environment

    Science.gov (United States)

    Zhu, Tong

    Nowadays, a significant portion of the power industry is under deregulation. Under this new circumstance, network security analysis is more critical and more difficult. One of the most important issues in network security analysis is voltage stability analysis. Due to the expected higher utilization of equipment induced by competition in a power market that covers bigger power systems, this issue is increasingly acute after deregulation. In this dissertation, some selected topics of voltage stability analysis are covered. In the first part, after a brief review of general concepts of continuation power flow (CPF), investigations on various matrix analysis techniques to improve the speed of CPF calculation for large systems are reported. Based on these improvements, a new CPF algorithm is proposed. This new method is then tested by an inter-area transaction in a large inter-connected power system. In the second part, the Arnoldi algorithm, the best method to find a few minimum singular values for a large sparse matrix, is introduced into the modal analysis for the first time. This new modal analysis is applied to the estimation of the point of voltage collapse and contingency evaluation in voltage security assessment. Simulations show that the new method is very efficient. In the third part, after transient voltage stability component models are investigated systematically, a novel system model for transient voltage stability analysis, which is a logical-algebraic-differential-difference equation (LADDE), is offered. As an example, TCSC (Thyristor controlled series capacitors) is addressed as a transient voltage stabilizing controller. After a TCSC transient voltage stability model is outlined, a new TCSC controller is proposed to enhance both fault related and load increasing related transient voltage stability. Its ability is proven by the simulation.

  16. Study of the breakdown voltage of SiPMs

    CERN Document Server

    Chmill, V; Klanner, R; Nitschke, M; Schwandt, J

    2016-01-01

    The breakdown behaviour of SiPMs (Silicon PhotoMultiplier) with pixel sizes of 15$\\times $15, 25$\\times $25, 50$\\times $50, and 100$\\times $100 $\\mu $m$^2$, manufactured by KETEK, has been investigated. From the current-voltage characteristics measured with and without illumination by LED light of 470 nm wavelength, the current-breakdown voltage, $V_I$, and from linear fits of the voltage dependence of the SiPM gain, measured by recording pulse-area spectra, the gain-breakdown voltage, $V_G$, have been obtained. The voltage dependence of the Geiger-breakdown probability was determined from the fraction of zero photoelectron events with LED illumination. By comparing the results to a model calculation, the photodetection-breakdown voltage, $V_{PD}$, has been determined. Within experimental uncertainties, $V_I$ and $V_{PD}$ are equal and independent of pixel size. For $V_G$, a dependence on pixel size is observed. The difference $V_I - V_G$ is about 1 V for the SiPM with 15 $\\mu $m pixels, decreases with pixel ...

  17. Study of the breakdown voltage of SiPMs

    Science.gov (United States)

    Chmill, V.; Garutti, E.; Klanner, R.; Nitschke, M.; Schwandt, J.

    2017-02-01

    The breakdown behaviour of SiPMs (Silicon PhotoMultiplier) with pixel sizes of 15 × 15 , 25 × 25 , 50 × 50, and 100 × 100 μm2, manufactured by KETEK, has been investigated. From the current-voltage characteristics measured with and without illumination by LED light of 470 nm wavelength, the current-breakdown voltage, VI, and from linear fits of the voltage dependence of the SiPM gain, measured by recording pulse-area spectra, the gain-breakdown voltage, VG, have been obtained. The voltage dependence of the Geiger-breakdown probability was determined from the fraction of zero photoelectron events with LED illumination. By comparing the results to a model calculation, the photodetection-breakdown voltage, VPD, has been determined. Within experimental uncertainties, VI and VPD are equal and independent of pixel size. For VG, a dependence on pixel size is observed. The difference VI -VG is about 1 V for the SiPM with 15 μm pixels, decreases with pixel size and is compatible with zero for the SiPM with 100 μm pixels.

  18. Elevated neuronal excitability due to modulation of the voltage-gated sodium channel Nav1.6 by Aβ1-42

    Directory of Open Access Journals (Sweden)

    Xi eWang

    2016-03-01

    Full Text Available Aberrant increases in neuronal network excitability may contribute to the cognitive deficits in Alzheimer’s disease (AD. However, the mechanisms underlying hyperexcitability are not fully understood. Such overexcitation of neuronal networks has been detected in the brains of APP/PS1 mice. In the present study, using current-clamp recording techniques, we observed that 12 days in vitro (DIV primary cultured pyramidal neurons from P0 APP/PS1 mice exhibited a more prominent action potential burst and a lower threshold than WT littermates. Moreover, after treatment with Aβ1-42 peptide, 12 DIV primary cultured neurons showed similar changes, to a greater degree than in controls. Voltage-clamp recordings revealed that the voltage-dependent sodium current density of neurons incubated with Aβ1-42 was significantly increased, without change in the voltage-dependent sodium channel kinetic characteristics. Immunohistochemistry and western blot results showed that, after treatment with Aβ1-42, expressions of Nav and Nav1.6 subtype increased in cultured neurons or APP/PS1 brains compared to control groups. The intrinsic neuronal hyperexcitability of APP/PS1 mice might thus be due to an increased expression of voltage-dependent sodium channels induced by Aβ1-42. These results may illuminate the mechanism of aberrant neuronal networks in AD.

  19. Performance Evaluation of Three Different Inverter Configurations of DVR for Mitigation of Voltage Events

    Directory of Open Access Journals (Sweden)

    Miska Prasad

    2016-12-01

    Full Text Available The voltage events namely voltage sags and voltage swells represent the most common, frequent and important power quality events in today’s power system. Dynamic voltage restorer (DVR is one of the key components used to mitigate the supply voltage quality disturbances in terms of voltage sags and swells in the distribution system. It consists of an energy storage unit, a voltage source inverter, a filter, a coupling transformer and the control system. This paper presents three different inverter configurations of dynamic voltage restorer (DVR for mitigation of voltage events such as voltage sags and swells with sudden addition or removal of the nonlinear load. These three configurations are voltage source inverter based DVR (VSI-DVR, current source inverter based DVR (CSI-DVR and impedance or Z-source inverter based DVR (ZSI-DVR. The d-q control technique is used to control the operation of the DVR. The response of ZSI-DVR for mitigation of voltage sags and swells are investigated and compared with VSI-DVR and CSI-DVR using MATLAB/SIMULINK environment.

  20. Electrode voltage fall and total voltage of a transient arc

    Science.gov (United States)

    Valensi, F.; Ratovoson, L.; Razafinimanana, M.; Masquère, M.; Freton, P.; Gleizes, A.

    2016-06-01

    This paper deals with an experimental study of the components of a transient arc total voltage with duration of a few tens of ms and a current peak close to 1000 A. The cathode tip is made of graphite whereas the flat anode is made either of copper or of graphite; the electrodes gap is a few mm. The analysis of the electrical parameters is supported and validated by fast imaging and by two models: the first one is a 2D physical model of the arc allowing to calculate both the plasma temperature field and the arc voltage; the second model is able to estimate the transient heating of the graphite electrode. The main aim of the study was to detect the possible change of the cathode voltage fall (CVF) during the first instants of the arc. Indeed it is expected that during the first ms the graphite cathode is rather cool and the main mechanism of the electron emission should be the field effect emission, whereas after several tens of ms the cathode is strongly heated and thermionic emission should be predominant. We have observed some change in the apparent CVF but we have shown that this apparent change can be attributed to the variation of the solid cathode resistance. On the other hand, the possible change of CVF corresponding to the transition between a ‘cold’ and a ‘hot’ cathode should be weak and could not be characterized considering our measurement uncertainty of about 2 V. The arc column voltage (ACV) was estimated by subtracting the electrode voltage fall from the total arc voltage. The experimental transient evolution of the ACV is in very good agreement with the theoretical variation predicted by the model, showing the good ability of the model to study this kind of transient arc.

  1. Warm Tropical Sea Surface Temperatures During the Pliocene: a New Record from Mg/Ca and δ18O In Situ Techniques

    Science.gov (United States)

    Wycech, J.; Kelly, D.; Kozdon, R.; Fournelle, J.; Valley, J. W.

    2013-12-01

    The Pliocene Warm Period (PWP) was a global warming event that punctuated Earth's climate history ~3 Ma, and study of its geologic record is providing important constraints for models predicting future climate change. Many sea surface temperature (SST) reconstructions for the PWP indicate amplified polar warmth with minimal or absent warming in the tropics - a phenomenon termed the cool tropics paradox. Key pieces of evidence for the lack of tropical warmth are oxygen isotope (δ18O) and Mg/Ca ratios in planktic foraminiferal shells. However, the δ18O data used to reconstruct surface-ocean conditions are derived from whole foraminiferal shells with the assumption that their geochemical compositions are well preserved and homogeneous. To the contrary, most planktic foraminiferal shells found in deep-sea sediments are an aggregate mixture of three carbonate phases (18O-depleted pre-gametogenic calcite, 18O-rich gametogenic calcite added during reproduction, and very 18O-rich diagenetic calcite) that formed under different physiological and/or environmental conditions. Here we report preliminary results of an ongoing study that uses secondary ion mass spectrometry (SIMS) and electron probe microanalysis (EPMA) to acquire in situ δ18O and Mg/Ca data, respectively, from 3-10 μm domains within individual planktic foraminiferal shells (Globigerinoides sacculifer) preserved in a PWP record recovered at ODP Site 806 in the West Pacific Warm Pool. SIMS analyses show that the δ18O of gametogenic calcite is 1-2‰ higher than in the pre-gametogenic calcite of Gs. sacculifer. Mass-balance calculations using the mean δ18O of gametogenic and pre-gametogenic calcites predict a whole-shell δ18O that is ~1.9‰ lower than the published whole-shell δ18O for Gs. sacculifer in this same deep-sea section. Removal of 18O-depleted, pre-gametogenic calcite via dissolution cannot fully account for this isotopic offset since the mean δ18O of whole shells (-1.3‰) is higher than that

  2. The role of local voltage potentials in outflow tract ectopy

    DEFF Research Database (Denmark)

    Thomsen, P.E.B.; Johannessen, A.; Jons, C.;

    2010-01-01

    Discrete, fragmented, local voltage potentials (LVPs) have been observed in electrograms recorded at the ablation site in patients undergoing radiofrequency ablation for arrhythmias originating in both the right and left ventricular outflow tract; however, the incidence and the significance...... for supraventricular arrhythmias served as controls. During sinus rhythm, LVPs were recorded in 24 of the 25 patients, 10-85 ms (41 +/- 19 ms) after the onset of the QRS complex, duration 33 +/- 11 ms, voltage 2.0 +/- 1.5 mV. The same potential was recorded 10-52 ms (mean 37 +/- 11 ms) prior to the V potential...... in the ventricular premature beats. In 10 patients, ventricular parasystole was suggested by varying coupling intervals > 100 ms, and fusion beats allowing for the estimation of the least common denominator of R-R intervals. In 23 of the 25 patients, the 12-lead electrocardiogram (ECG) and intracardiac contact...

  3. Unbalanced Voltage Compensation in Low Voltage Residential AC Grids

    DEFF Research Database (Denmark)

    Trintis, Ionut; Douglass, Philip; Munk-Nielsen, Stig

    2016-01-01

    This paper describes the design and test of a control algorithm for active front-end rectifiers that draw power from a residential AC grid to feed heat pump loads. The control algorithm is able to control the phase to neutral or phase to phase RMS voltages at the point of common coupling....... The voltage control was evaluated with either active or reactive independent phase load current control. The control performance in field operation in a residential grid situated in Bornholm, Denmark was investigated for different use cases....

  4. Voltage synchronizations between multichannel electroencephalograms during epileptic seizures

    CERN Document Server

    Tuncay, Caglar

    2010-01-01

    The underlying dynamics for the electroencephalographic (EEG) recordings from humans but especially epilepsy patients are usually not completely known. However, the ictal activity is claimed to be characterized by synchronous oscillations in the brain voltages in the literature. These time dependent interdependencies (synchronization, coupling) between the EEG voltages from epileptogenic and non epileptogenic brain sites of nineteen focal epileptic patients are investigated in this work. It is found that strong synchronizationdesynchronization events occur in alternation during most of the investigated seizures. Thus, these seizures are detected with considerable sensitivity (71 of the 79 seizures).

  5. The effect of protein kinase C on voltage-gated potassium channel in pulmonary artery smooth muscle cells from rats exposed to chronic hypoxia

    Institute of Scientific and Technical Information of China (English)

    张永昶; 倪望; 张珍祥; 徐永健

    2004-01-01

    Background Chronic hypoxia can cause pulmonary hypertension and pulmonary heart disease with high mortality.The signal transduction pathway of protein kinase C (PKC) plays an important role in chronic pulmonary hypertension. So it is necessary to investigate the effect of PKC on voltage-gated potassium (K+) channels in pulmonary artery smooth muscle cells of rats exposed to chronic hypoxia.Methods Male Wistar rats were randomly divided into a control group (group A) and a chronic hypoxia group (group B). Group B received hypoxia [oxygen concentration (10±1)%] eight hours per day for four consecutive weeks. Single pulmonary artery smooth muscle cells were obtained using an acute enzyme separation method. Conventional whole cell patch clamp technique was used to record resting membrane potential, membrane capacitance and voltage-gated K+ currents. The changes in voltage-gated K+ currents before and after applying paramethoxyamphetamine (PMA) (500 nmol/L), an agonist of PKC, and PMA plus carbohydrate mixture of glucose, fructose and xylitol (GFX) (30 nmol/L), an inhibitor of PKC, were compared between the two groups. Results The resting membrane potential in group B was significantly lower than that of group A: -(29.0±4.8) mV (n=18) vs -(42.5±4.6) mV (n=35) (P0.05). The voltage-gated K+ currents were significantly inhibited by PMA in group A, and this effect was reversed by GFX. However, the voltage-gated K+ currents in group B were not affected by PMA.Conclusions The resting membrane potential and voltage-gated K+ currents in pulmonary artery smooth muscle cells from rats exposed to chronic hypoxia decreased significantly. It seems that PKC has different effects on the voltage-gated K+ currents of pulmonary artery smooth muscle cells under different conditions.

  6. Cooperative Control with Virtual Selective Harmonic Capacitance for Harmonic Voltage Compensation in Islanded MicroGrids

    DEFF Research Database (Denmark)

    Micallef, A.; Apap, M.; Spitero-Stanies, C.

    2012-01-01

    This paper focuses on the islanded operation of microgrids. In this mode of operation, the microsources are required to cooperate autonomously to regulate the local grid voltage and frequency. Droop control is typically used to achieve this autonomous voltage and frequency regulation. Inverters...... having LCL output filters would cause voltage distortion to be present at the PCC of the local load when non-linear current is supplied to the load due to the voltage drop across the grid side inductor. Techniques to reduce the output voltage distortion typically consist of installing either passive...... loop, implemented in each of the microsource inverters, is proposed so as to dampen the voltage harmonics at the PCC of the local load. Simulation results are presented showing the suitability of the proposed algorithm in dampening the PCC voltage harmonics....

  7. Automated Voltage Control in LHCb

    CERN Document Server

    Granado Cardoso, L; Jacobsson, R

    2011-01-01

    LHCb is one of the 4 LHC experiments. In order to ensure the safety of the detector and to maximize efficiency, LHCb needs to coordinate its own operations, in particular the voltage configuration of the different subdetectors, according to the accelerator status. A control software has been developed for this purpose, based on the Finite State Machine toolkit and the SCADA system used for control throughout LHCb (and the other LHC experiments). This software permits to efficiently drive both the Low Voltage (LV) and High Voltage (HV) systems of the 10 different sub-detectors that constitute LHCb, setting each sub-system to the required voltage (easily configurable at run-time) based on the accelerator state. The control software is also responsible for monitoring the state of the Sub-detector voltages and adding it to the event data in the form of status-bits. Safe and yet flexible operation of the LHCb detector has been obtained and automatic actions, triggered by the state changes of the ...

  8. Optimal planning of high voltage distribution substations

    Institute of Scientific and Technical Information of China (English)

    YU Yixin; YAN Xuefei; ZHANG Yongwu

    2007-01-01

    Aimed at solving the problem of optimal planning for high voltage distribution substations,an efficient method is put forward.The method divides the problem into two sub-problems:source locating and combinational optimization.The algorithm of allocating and locating alternatively (ALA) is widely used to deal with the source locating problem,but it is dependent on the initial location to a large degree.Thus,some modifications were made to the ALA algorithm,which could greatly improve the quality of solutions.In addition,considering the non-convex and nonconcave nature of the sub-problem of combinational optimization,the branch-and-bound technique was adopted to obtain or approximate a global optimal solution.To improve the efficiency of the branch-and-bound technique,some heuristic principles were proposed to cut those branches that may generate a global optimization solution with low probability.Examples show that the proposed algorithm meets the requirement of engineering and it is an effective approach to rapidly solve the problem of optimal planning for high voltage distribution substations.

  9. Common-mode Voltage Reduction in a Motor Drive System with a Power Factor Correction

    DEFF Research Database (Denmark)

    Adabi, J.; Boora, A.A.; Zare, F.;

    2012-01-01

    to reduce shaft voltage in a three-phase AC motor drive system. In this topology, the AC-DC diode rectifier influences the common-mode voltage generated by the inverter because the placement of the neutral point is changing in different rectifier circuit states. A pulse width modulation technique......Common-mode voltage generated by a power converter in combination with parasitic capacitive couplings is a potential source of shaft voltage in an AC motor drive system. In this study, a three-phase motor drive system supplied with a single-phase AC-DC diode rectifier is investigated in order...... is presented by a proper placement of the zero vectors to reduce the common-mode voltage level, which leads to a cost-effective shaft voltage reduction technique without load current distortion, while keeping the switching frequency constant. Analysis, simulations and experimental implementation have been...

  10. Development of a New Cascade Voltage-Doubler for Voltage Multiplication

    OpenAIRE

    Arash Toudeshki; Norman Mariun; Hashim Hizam; Noor Izzri Abdul Wahab

    2014-01-01

    For more than eight decades, cascade voltage-doubler circuits are used as a method to produce DC output voltage higher than the input voltage. In this paper, the topological developments of cascade voltage-doublers are reviewed. A new circuit configuration for cascade voltage-doubler is presented. This circuit can produce a higher value of the DC output voltage and better output quality compared to the conventional cascade voltage-doubler circuits, with the same number of stages.

  11. Low-Energy Real-Time OS Using Voltage Scheduling Algorithm for Variable Voltage Processors

    OpenAIRE

    Okuma, Takanori; Yasuura, Hiroto

    2001-01-01

    This paper presents a real-time OS based on $ mu $ITRON using proposed voltage scheduling algorithm for variable voltage processors which can vary supply voltage dynamically. The proposed voltage scheduling algorithms assign voltage level for each task dynamically in order to minimize energy consumption under timing constraints. Using the presented real-time OS, running tasks with low supply voltage leads to drastic energy reduction. In addition, the presented voltage scheduling algorithm is ...

  12. Simple buck/boost voltage regulator

    Science.gov (United States)

    Paulkovich, J.; Rodriguez, G. E.

    1980-01-01

    Circuit corrects low or high supply voltage, produces regulated output voltage. Circuit has fewer components because inductory/transformer combination and pulse-width modulator serve double duty. Regulator handles input voltage variation from as low as one half output voltage to as high as input transistor rating. Solar arrays, fuel cells, and thermionic generators might use this regulator.

  13. 30 CFR 18.47 - Voltage limitation.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Voltage limitation. 18.47 Section 18.47 Mineral... § 18.47 Voltage limitation. (a) A tool or switch held in the operator's hand or supported against his... particular voltage(s) are provided in the design and construction of the equipment, its wiring,...

  14. Cavity Voltage Phase Modulation MD

    CERN Document Server

    Mastoridis, Themistoklis; Molendijk, John; Timko, Helga; CERN. Geneva. ATS Department

    2016-01-01

    The LHC RF/LLRF system is currently configured for extremely stable RF voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal beam current since the demanded power would exceed the peak klystron power and lead to saturation. A new scheme has therefore been proposed: for beam currents above nominal (and possibly earlier), the cavity phase modulation by the beam will not be corrected (transient beam loading), but the strong RF feedback and One-Turn Delay feedback will still be active for loop and beam stability in physics. To achieve this, the voltage set point will be adapted for each bunch. The goal of this MD was to test a new algorithm that would adjust the voltage set point to achieve the cavity phase modulation that would minimize klystron forward power.

  15. Portable High Voltage Impulse Generator

    Directory of Open Access Journals (Sweden)

    S. Gómez

    2011-07-01

    Full Text Available This paper presents a portable high voltage impulse generator which was designed and built with insulation up to 20 kV. This design was based on previous work in which simulation software for standard waves was developed. Commercial components and low-cost components were used in this work; however, these particular elements are not generally used for high voltage applications. The impulse generators used in industry and laboratories are usually expensive; they are built to withstand extra high voltage and they are big, making them impossible to transport. The proposed generator is portable, thereby allowing tests to be made on devices that cannot be moved from their location. The results obtained with the proposed impulse generator were satisfactory in terms of time and waveforms compared to other commercial impulse generators and the standard impulse wave simulator.

  16. Initial progress in the recording of crime scene simulations using 3D laser structured light imagery techniques for law enforcement and forensic applications

    Science.gov (United States)

    Altschuler, Bruce R.; Monson, Keith L.

    1998-03-01

    Representation of crime scenes as virtual reality 3D computer displays promises to become a useful and important tool for law enforcement evaluation and analysis, forensic identification and pathological study and archival presentation during court proceedings. Use of these methods for assessment of evidentiary materials demands complete accuracy of reproduction of the original scene, both in data collection and in its eventual virtual reality representation. The recording of spatially accurate information as soon as possible after first arrival of law enforcement personnel is advantageous for unstable or hazardous crime scenes and reduces the possibility that either inadvertent measurement error or deliberate falsification may occur or be alleged concerning processing of a scene. Detailed measurements and multimedia archiving of critical surface topographical details in a calibrated, uniform, consistent and standardized quantitative 3D coordinate method are needed. These methods would afford professional personnel in initial contact with a crime scene the means for remote, non-contacting, immediate, thorough and unequivocal documentation of the contents of the scene. Measurements of the relative and absolute global positions of object sand victims, and their dispositions within the scene before their relocation and detailed examination, could be made. Resolution must be sufficient to map both small and large objects. Equipment must be able to map regions at varied resolution as collected from different perspectives. Progress is presented in devising methods for collecting and archiving 3D spatial numerical data from crime scenes, sufficient for law enforcement needs, by remote laser structured light and video imagery. Two types of simulation studies were done. One study evaluated the potential of 3D topographic mapping and 3D telepresence using a robotic platform for explosive ordnance disassembly. The second study involved using the laser mapping system on a

  17. A voltage-dependent persistent sodium current in mammalian hippocampal neurons.

    Science.gov (United States)

    French, C R; Sah, P; Buckett, K J; Gage, P W

    1990-06-01

    Currents generated by depolarizing voltage pulses were recorded in neurons from the pyramidal cell layer of the CA1 region of rat or guinea pig hippocampus with single electrode voltage-clamp or tight-seal whole-cell voltage-clamp techniques. In neurons in situ in slices, and in dissociated neurons, subtraction of currents generated by identical depolarizing voltage pulses before and after exposure to tetrodotoxin revealed a small, persistent current after the transient current. These currents could also be recorded directly in dissociated neurons in which other ionic currents were effectively suppressed. It was concluded that the persistent current was carried by sodium ions because it was blocked by TTX, decreased in amplitude when extracellular sodium concentration was reduced, and was not blocked by cadmium. The amplitude of the persistent sodium current varied with clamp potential, being detectable at potentials as negative as -70 mV and reaching a maximum at approximately -40 mV. The maximum amplitude at -40 mV in 21 cells in slices was -0.34 +/- 0.05 nA (mean +/- 1 SEM) and -0.21 +/- 0.05 nA in 10 dissociated neurons. Persistent sodium conductance increased sigmoidally with a potential between -70 and -30 mV and could be fitted with the Boltzmann equation, g = gmax/(1 + exp[(V' - V)/k)]). The average gmax was 7.8 +/- 1.1 nS in the 21 neurons in slices and 4.4 +/- 1.6 nS in the 10 dissociated cells that had lost their processes indicating that the channels responsible are probably most densely aggregated on or close to the soma. The half-maximum conductance occurred close to -50 mV, both in neurons in slices and in dissociated neurons, and the slope factor (k) was 5-9 mV. The persistent sodium current was much more resistant to inactivation by depolarization than the transient current and could be recorded at greater than 50% of its normal amplitude when the transient current was completely inactivated. Because the persistent sodium current activates at

  18. Phase-lock loop of Grid-connected Voltage Source Converter under non-ideal grid condition

    DEFF Research Database (Denmark)

    Wang, Haojie; Sun, Hai; Han, Minxiao

    2015-01-01

    phase information cannot be accurately tracked. Based on analysis of the cause of double-frequency ripple when unbalance exists in main grid, a phase-locked loop (PLL) detection technique is proposed. Under the conditions of unsymmetrical system voltage, varying system frequency, single-phase system...... and distorted system voltage the proposed PLL can accurately detect the fundamental positive-sequence component of grid voltage thus accurate control of DC micro-grid voltage can be realized....

  19. A low voltage CMOS low drop-out voltage regulator

    Science.gov (United States)

    Bakr, Salma Ali; Abbasi, Tanvir Ahmad; Abbasi, Mohammas Suhaib; Aldessouky, Mohamed Samir; Abbasi, Mohammad Usaid

    2009-05-01

    A low voltage implementation of a CMOS Low Drop-Out voltage regulator (LDO) is presented. The requirement of low voltage devices is crucial for portable devices that require extensive computations in a low power environment. The LDO is implemented in 90nm generic CMOS technology. It generates a fixed 0.8V from a 2.5V supply which on discharging goes to 1V. The buffer stage used is unity gain configured unbuffered OpAmp with rail-to-rail swing input stage. The simulation result shows that the implemented circuit provides load regulation of 0.004%/mA and line regulation of -11.09mV/V. The LDO provides full load transient response with a settling time of 5.2μs. Further, the dropout voltage is 200mV and the quiescent current through the pass transistor (Iload=0) is 20μA. The total power consumption of this LDO (excluding bandgap reference) is only 80μW.

  20. Implementation of Dynamic Voltage Restorer for Mitigation of Voltage Sag

    Directory of Open Access Journals (Sweden)

    K.Vinod Kumar

    2013-07-01

    Full Text Available Power quality is one of major concerns in the present. It has become important, especially with the introduction of sophisticated devices, whose performance is very sensitive to the quality of power supply. The dynamic voltage restorer (DVR is one of the modern devices used in distribution systems to improve the power quality. In this paper, emergency control in distribution systems is discussed by using the proposed multifunctional DVR control strategy.Also, themultiloop controller using the Posicast and P+Resonant controllers is proposed in order to improve the transient response and eliminate the steady state error in DVR response,respectively.The proposed process is applied to some riots in load voltage effected by induction motors starting, and a three-phase short circuit fault. The three-phase short circuits, and the large induction motors are suddenly started then voltage sags areoccurred.The innovation here is that by using the Multifunctional Dynamic Voltage Restorer, improve the power quality in distribution side. Simulation results show the capability of the DVR to control the emergency conditions of the distribution systems by using MATLAB/Simulink software.

  1. A Transformerless Medium Voltage Multiphase Motor Drive System

    Directory of Open Access Journals (Sweden)

    Dan Wang

    2016-04-01

    Full Text Available A multiphase motor has several major advantages, such as high reliability, fault tolerance, and high power density. It is a critical issue to develop a reliable and efficient multiphase motor drive system. In this paper, a transformerless voltage source converter-based drive system for a medium-voltage (MV multiphase motor is proposed. This drive converter employs cascaded H-bridge rectifiers loaded by H-bridge inverters as the interface between the grid and multiphase motor. The cascaded H-bridge rectifier technique makes the drive system able to be directly connected to the MV grid without the phase-shifting transformer because it can offset the voltage level gap between the MV grid and the semiconductor devices, provide near-sinusoidal AC terminal voltages without filters, and draw sinusoidal line current from the grid. Based on a digital signal processor (DSP, a complete improved Phase Disposition Pulse Width Modulation (PD-PWM method is developed to ensure the individual DC-link capacitor voltage balancing for enhancing the controllability and limiting the voltage and power stress on the H-bridge cells. A downscaled prototype is designed and developed based on a nine-phase motor. The experimental results verify the excellent performances of the proposed drive system and control strategy in steady-state and variant-frequency startup operations.

  2. The high voltage homopolar generator

    Science.gov (United States)

    Price, J. H.; Gully, J. H.; Driga, M. D.

    1986-11-01

    System and component design features of proposed high voltage homopolar generator (HVHPG) are described. The system is to have an open circuit voltage of 500 V, a peak output current of 500 kA, 3.25 MJ of stored inertial energy and possess an average magnetic-flux density of 5 T. Stator assembly components are discussed, including the stator, mount structure, hydrostatic bearings, main and motoring brushgears and rotor. Planned operational procedures such as monitoring the rotor to full speed and operation with a superconducting field coil are delineated.

  3. Capacitance of High-Voltage Coaxial Cable in Plasma Immersion Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Plasma immersion ion implantation (PIII) is an excellent technique for the surface modification of complex-shaped components. Owing to pulsed operation mode of the high voltage and large slew rate, the capacitance on the high-voltage coaxial cable can be detrimental to the processand cannot be ignored. In fact, a significant portion of the rise-time/fall-time of the implantation voltage pulse and big initial current can be attributed to the coaxial cable.

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

    OpenAIRE

    2016-01-01

    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...

  5. Doubly-Fed Induction Generator Control Under Voltage Sags

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Blaabjerg, Frede; Lima, K.;

    2008-01-01

    This paper proposes a new control technique to improve the fault-ride through capability of doubly fed induction generators (DFIG). In such generators the appearance of severe voltage sags at the coupling point make rise to high over currents at the rotor/stator windings, something that makes...

  6. Resilient architecture design for voltage variation

    CERN Document Server

    Reddi, Vijay Janapa

    2013-01-01

    Shrinking feature size and diminishing supply voltage are making circuits sensitive to supply voltage fluctuations within the microprocessor, caused by normal workload activity changes. If left unattended, voltage fluctuations can lead to timing violations or even transistor lifetime issues that degrade processor robustness. Mechanisms that learn to tolerate, avoid, and eliminate voltage fluctuations based on program and microarchitectural events can help steer the processor clear of danger, thus enabling tighter voltage margins that improve performance or lower power consumption. We describe

  7. Voltage-Induced Effect on Resistance of C:N/Si Heterojunctions

    Institute of Scientific and Technical Information of China (English)

    GAO Xi-Li; ZHANG Xiao-Zhong; WAN Cai-Hua; WANG Ji-Min

    2012-01-01

    Nitrogen doped a-C/Silicon (a-C:N/Si) heterojunctions have been fabricated by using the pulsed laser deposition (PLD) technique and their current-voltage characteristics at various temperatures are investigated.For reverse applied voltages,a-C:N/Si heterojunctions exhibit metal-insulator transition characteristics and the transition temperature can be controlled by the applied voltages.After the excitation of repeated high reverse applied voltages,the current-voltage curves show obvious hysteresis behaviors at low temperatures.These hysteresis behaviors are reproducible and the ratio of the high/low resistance can be greater than 104.%Nitrogen doped a-C/Silicon (a-C:N/Si) heterojunctions have been fabricated by using the pulsed laser deposition (PLD) technique and their current-voltage characteristics at various temperatures are investigated. For reverse applied voltages, a-C.N/Si heterojunctions exhibit metal-insulator transition characteristics and the transition temperature can be controlled by the applied voltages. After the excitation of repeated high reverse applied voltages, the current-voltage curves show obvious hysteresis behaviors at low temperatures. These hysteresis behaviors are reproducible and the ratio of the high/low resistance can be greater than 104.

  8. Fisiopatología y técnicas de registro de los movimientos oculares Physiopathology and recording techniques of ocular movements

    Directory of Open Access Journals (Sweden)

    L. Gila

    2009-01-01

    neuronal systems can be altered by many neurological processes of different kinds and localizations, causing a broad variety of oculomotor disturbances. The most salient aspects of the physiopathology and the recording systems of eye movements are reviewed.

  9. Modulation of voltage-gated sodium channels hyperpolarizes the voltage threshold for activation in spinal motoneurones.

    Science.gov (United States)

    Power, Kevin E; Carlin, Kevin P; Fedirchuk, Brent

    2012-03-01

    Previous work has shown that motoneurone excitability is enhanced by a hyperpolarization of the membrane potential at which an action potential is initiated (V(th)) at the onset, and throughout brainstem-evoked fictive locomotion in the adult decerebrate cat and neonatal rat. Modeling work has suggested the modulation of Na(+) conductance as a putative mechanism underlying this state-dependent change in excitability. This study sought to determine whether modulation of voltage-gated sodium channels could induce V(th) hyperpolarization. Whole-cell patch-clamp recordings were made from antidromically identified lumbar spinal motoneurones in an isolated neonatal rat spinal cord preparation. Recordings were made with and without the bath application of veratridine, a plant alkaloid neurotoxin that acts as a sodium channel modulator. As seen in HEK 293 cells expressing Nav1.2 channels, veratridine-modified channels demonstrated a hyperpolarizing shift in their voltage-dependence of activation and a slowing of inactivation that resulted in an enhanced inward current in response to voltage ramp stimulations. In the native rat motoneurones, veratridine-modified sodium channels induced a hyperpolarization of V(th) in all 29 neonatal rat motoneurones examined (mean hyperpolarization: -6.6 ± 4.3 mV). V(th) hyperpolarization was not due to the effects on Ca(2+) and/or K(+) channels as blockade of these currents did not alter V(th). Veratridine also significantly increased the amplitude of persistent inward currents (PICs; mean increase: 72.5 ± 98.5 pA) evoked in response to slow depolarizing current ramps. However, the enhancement of the PIC amplitude had a slower time course than the hyperpolarization of V(th), and the PIC onset voltage could be either depolarized or hyperpolarized, suggesting that PIC facilitation did not mediate the V(th) hyperpolarization. We therefore suggest that central neuronal circuitry in mammals could affect V(th) in a mechanism similar to that of

  10. Wide Operational Range Processor Power Delivery Design for Both Super-Threshold Voltage and Near-Threshold Voltage Computing

    Institute of Scientific and Technical Information of China (English)

    Xin He; Gui-Hai Yan; Yin-He Han; Xiao-Wei Li

    2016-01-01

    The load power range of modern processors is greatly enlarged because many advanced power management techniques are employed, such as dynamic voltage frequency scaling, Turbo Boosting, and near-threshold voltage (NTV) technologies. However, because the efficiency of power delivery varies greatly with different load conditions, conventional power delivery designs cannot maintain high efficiency over the entire voltage spectrum, and the gained power saving may be offset by power loss in power delivery. We propose SuperRange, a wide operational range power delivery unit. SuperRange complements the power delivery capability of on-chip voltage regulator and off-chip voltage regulator. On top of SuperRange, we analyze its power conversion characteristics and propose a voltage regulator (VR) aware power management algorithm. Moreover, as more and more cores have been integrated on a singe chip, multiple SuperRange units can serve as basic building blocks to build, in a highly scalable way, more powerful power delivery subsystem with larger power capacity. Experimental results show SuperRange unit offers 1x and 1.3x higher power conversion efficiency (PCE) than other two conventional power delivery schemes at NTV region and exhibits an average 70%PCE over entire operational range. It also exhibits superior resilience to power-constrained systems.

  11. Energy reduction through voltage scaling and lightweight checking

    Science.gov (United States)

    Kadric, Edin

    As the semiconductor roadmap reaches smaller feature sizes and the end of Dennard Scaling, design goals change, and managing the power envelope often dominates delay minimization. Voltage scaling remains a powerful tool to reduce energy. We find that it results in about 60% geomean energy reduction on top of other common low-energy optimizations with 22nm CMOS technology. However, when voltage is reduced, it becomes easier for noise and particle strikes to upset a node, potentially causing Silent Data Corruption (SDC). The 60% energy reduction, therefore, comes with a significant drop in reliability. Duplication with checking and triple-modular redundancy are traditional approaches used to combat transient errors, but spending 2--3x the energy for redundant computation can diminish or reverse the benefits of voltage scaling. As an alternative, we explore the opportunity to use checking operations that are cheaper than the base computation they are guarding. We devise a classification system for applications and their lightweight checking characteristics. In particular, we identify and evaluate the effectiveness of lightweight checks in a broad set of common tasks in scientific computing and signal processing. We find that the lightweight checks cost only a fraction of the base computation (0-25%) and allow us to recover the reliability losses from voltage scaling. Overall, we show about 50% net energy reduction without compromising reliability compared to operation at the nominal voltage. We use FPGAs (Field-Programmable Gate Arrays) in our work, although the same ideas can be applied to different systems. On top of voltage scaling, we explore other common low-energy techniques for FPGAs: transmission gates, gate boosting, power gating, low-leakage (high-Vth) processes, and dual-V dd architectures. We do not scale voltage for memories, so lower voltages help us reduce logic and interconnect energy, but not memory energy. At lower voltages, memories become dominant

  12. PSO-Based Voltage Control Strategy for Loadability Enhancement in Smart Power Grids

    Directory of Open Access Journals (Sweden)

    Heng-Yi Su

    2016-12-01

    Full Text Available This paper proposes a new voltage control methodology using the particle swarm optimization (PSO technique for smart grid loadability enhancement. The goal of this paper is to achieve reliable and efficient voltage profile/stability regulation in power grids. This methodology is based on the decouple power flow equations and the worst-case design technique. Specifically, the secondary voltage control (SVC problem is formulated as an L-infinity norm minimization problem which considers overall load voltage deviations in electrical power systems as an objective model, and the PSO technique is employed to determine a robust control action which aims to improve voltage profile and to enlarge transmission grid loadability by optimal coordinated control of VAR sources. The methodology was successfully tested on several IEEE benchmark systems.

  13. VOLTAGE REGULATORS OF SYNCHRONOUS GENERATORS

    Directory of Open Access Journals (Sweden)

    Grigorash O. V.

    2015-06-01

    Full Text Available Synchronous generators are the primary source of electrical power autonomous electrosupply systems, including backup systems. They are also used in a structure of rotating electricity converters and are widely used in renewable energy as part of wind power plants of small, mini and micro hydroelectric plants. Increasing the speed and the accuracy of the system of the voltage regulation of synchronous generators is possible due to the development of combined systems containing more stabilizers. The article illustrates the functional schemes of circuit voltage stabilizers and frequency synchronous generators (with electromagnetic excitation and permanent magnet excitation and describes the features of their work, including two and three-aggregate rotating converters of electricity used in uninterruptible power supply systems. To improve the technical characteristics of the system of stabilization we have proposed functional solutions for stabilizers of synchronous generators made on the base of direct frequency converters and using a transformer with a rotating magnetic field. To improve the reliability of and to improve the operational characteristics of the autonomous independent sources of electricity we suggest creating the main functional blocks and the elements of the stabilization system in a modular way. The functional circuit solutions of voltage regulators of synchronous generators and the characteristics of their work considered in the article, are able to improve the efficiency of pre-design work in the development of new technical solutions for stabilizing the voltage and the frequency in synchronous generators of electrosupply autonomous systems

  14. Frequency-controlled voltage regulator

    Science.gov (United States)

    Mclyman, W. T.

    1980-01-01

    Converting input ac to higher frequency reduce size and weight and makes possible unique kind of regulation. Since conversion frequency is above range of human hearing, supply generated on audible noise. It also exploits highfrequency conversion features to regulate its output voltage in novel way. Circuit is inherently short-circuit proof.

  15. Robert Recorde

    CERN Document Server

    Williams, Jack

    2011-01-01

    The 16th-Century intellectual Robert Recorde is chiefly remembered for introducing the equals sign into algebra, yet the greater significance and broader scope of his work is often overlooked. This book presents an authoritative and in-depth analysis of the man, his achievements and his historical importance. This scholarly yet accessible work examines the latest evidence on all aspects of Recorde's life, throwing new light on a character deserving of greater recognition. Topics and features: presents a concise chronology of Recorde's life; examines his published works; describes Recorde's pro

  16. A SQUID gradiometer module with wire-wound pickup antenna and integrated voltage feedback circuit

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Guofeng [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Yi, E-mail: y.zhang@fz-juelich.de [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Zhang Shulin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Krause, Hans-Joachim [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); and others

    2012-10-15

    The performance of the direct readout schemes for dc SQUID, Additional Positive Feedback (APF), noise cancellation (NC) and SQUID bootstrap circuit (SBC), have been studied in conjunction with planar SQUID magnetometers. In this paper, we examine the NC technique applied to a niobium SQUID gradiometer module with an Nb wire-wound antenna connecting to a dual-loop SQUID chip with an integrated voltage feedback circuit for suppression of the preamplifier noise contribution. The sensitivity of the SQUID gradiometer module is measured to be about 1 fT/(cm {radical}Hz) in the white noise range in a magnetically shielded room. Using such gradiometer, both MCG and MEG signals are recorded.

  17. A comparative study for Triple-Rule-out with different tube voltage technique of Dual-Source CT in acute chest pain%双源 CT不同管电压技术诊断急性胸痛三联症效果比较

    Institute of Scientific and Technical Information of China (English)

    王皆欢; 陈东风; 王少春; 孙占国; 王林省; 张谷青

    2014-01-01

    目的:对比双源CT胸痛三联检查在两种不同电压下显示急性胸痛患者肺动脉、主动脉及冠状动脉的图像质量以及患者所受的辐射剂量,以评估低电压扫描在急性胸痛患者推广应用的可行性。方法利用双源C T胸痛三联扫描模式,结合回顾性心电门控技术对361例胸痛三联检查患者进行统计分析,比较主动脉、肺动脉及冠状动脉的图像质量及辐射的有效剂量。结果120kV组与100kV组在图像质量的主观评分对比中差异无统计学意义(P>0.05),在患者辐射剂量的对比中,120kV组的辐射剂量大于100kV组,差异有统计学意义(P<0.05)。结论双源CT胸痛三联检查两种不同管电压扫描对急性胸痛患者的肺动脉、主动脉及冠状动脉的成像质量无影响,并且应用100kV 管电压扫描可以降低患者所受的辐射剂量,可以作为急性胸痛患者的首选。%Objective To compare the value of triple-rule-out (TRO) dual-source computed tomography angiog-raphy in acute chest pain patients with diseases of pulmonary artery ,aortic and coronary artery and radiation dose in two different voltage as well as the feasibility of generalizing and applying in patients with acute chest pain . Methods 361 patients with chest pain were analyzed statistically underwent triple-rule-out (TRO) dual-source CT combined with retrospective ECG-gated technique ,and then compare with image quality of aorta ,pulmonary artery and coronary artery and effective radiation dose .Results Subjective score of image quality of the voltage 120kV and 100kV group had no statistical significance(P>0.05) .The difference was statistically significant(P<0.05)in comparison of radiation dose .The effective radiation dose of the voltage 100kV group was lower than that of the voltage 120kV group .Conclusion The quality of pictures of pulmonary artery ,coronary artery and aorta are not affected in different tube tension

  18. Voltage-gated Proton Channels

    Science.gov (United States)

    DeCoursey, Thomas E.

    2014-01-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance ~103 smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn2+ (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H+ for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

  19. The Voltage Boost Enabled by Luminescence Extraction in Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Ganapati, Vidya; Steiner, Myles A.; Yablonovitch, Eli

    2016-11-21

    A new physical principle has emerged to produce record voltages and efficiencies in photovoltaic cells, 'luminescence extraction.' This is exemplified by the mantra 'a good solar cell should also be a good LED.' Luminescence extraction is the escape of internal photons out of the front surface of a solar cell. Basic thermodynamics says that the voltage boost should be related to concentration ratio, C, of a resource by ..delta..V=(kT/q)ln{C}. In light trapping, (i.e. when the solar cell is textured and has a perfect back mirror) the concentration ratio of photons C={4n2}, so one would expect a voltage boost of ..delta..V=kT ln{4n2} over a solar cell with no texture and zero back reflectivity, where n is the refractive index. Nevertheless, there has been ambiguity over the voltage benefit to be expected from perfect luminescence extraction. Do we gain an open circuit voltage boost of ..delta..V=(kT/q)ln{n2}, ..delta..V=(kT/q)ln{2n2}, or ..delta..V=(kT/q)ln{4n2}? What is responsible for this voltage ambiguity ..delta..V=(kT/q)ln{4}=36mVolts? We show that different results come about, depending on whether the photovoltaic cell is optically thin or thick to its internal luminescence. In realistic intermediate cases of optical thickness the voltage boost falls in between; ln{n2}q..delta..V/kT)<;ln{4n2}.

  20. Neutral-point voltage dynamic model of three-level NPC inverter for reactive load

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, Sergio

    2012-01-01

    A three-level neutral-point-clamped inverter needs a controller for the neutral-point voltage. Typically, the controller design is based on a dynamic model. The dynamic model of the neutral-point voltage depends on the pulse width modulation technique used for the inverter. A pulse width modulati...

  1. Kinetics properties of voltage induced colicin Ia channels into a lipid bilayer

    CERN Document Server

    Cassia-Moura, R

    1998-01-01

    The activation kinetics of the ion channels formed by colicin Ia incorporated into a planar bilayer lipid membrane (BLM) was investigated by the voltage clamp technique using different step voltage stimuli. The temporal behaviour of ion channels put in evidence a gain or a loss of memory, revealed by a specific sequence of electrical pulses used for stimulation.

  2. Supervisory hybrid model predictive control for voltage stability of power networks

    NARCIS (Netherlands)

    Negenborn, R.R.; Beccuti, A.G.; Demiray, T.; Leirens, S.; Damm, G.; De Schutter, B.; Morari, M.

    2007-01-01

    Emergency voltage control problems in electric power networks have stimulated the interest for the implementation of online optimal control techniques. Briefly stated, voltage instability stems from the attempt of load dynamics to restore power consumption beyond the capability of the transmission a

  3. Optimal Cooperative Management of Energy Storage Systems to Deal with Over- and Under-Voltages

    DEFF Research Database (Denmark)

    Mokhtari, Ghassem; Nourbakhsh, Ghavameddin; Anvari-Moghaddam, Amjad

    2017-01-01

    This paper presents an optimal cooperative voltage control approach, which coordinates storage units in a distribution network. This technique is developed for storage systems’ active power management with a local strategy to provide robust voltage control and a distributed strategy to deliver op...

  4. Buck supplies output voltage ripple reduction using fuzzy control

    Directory of Open Access Journals (Sweden)

    Nicu BIZON

    2007-12-01

    Full Text Available Using the PWM control for switching power supplies the peaks EMI noise appear at the switching frequency and its harmonics. Using randomize or chaotic PWM control techniques in these systems the power spectrum is spread out in all frequencies band spectral emissions, but with a bigger ripple in the output voltage. The proposed nonlinear feedback control method, which induces chaos, is based by fuzzy rules that minimize the output voltage ripple. The feasibility and effectiveness of this relative simple method is shown by simulation. A comparison with the previous control method is included, too.

  5. Voltage rise mitigation for solar PV integration at LV grids

    DEFF Research Database (Denmark)

    Yang, Guangya; Marra, Francesco; Juamperez Goñi, Miguel Angel

    2015-01-01

    Solar energy from photovoltaic (PV) is among the fastest developing renewable energy systems worldwide. Driven by governmental subsidies and technological development, Europe has seen a fast expansion of solar PV in the last few years. Among the installed PV plants, most of them are situated...... at the distribution systems and bring various operational challenges such as power quality and power flow management. The paper discusses the modelling requirements for PV system integration studies, as well as the possible techniques for voltage rise mitigation at low voltage (LV) grids for increasing PV penetration...

  6. Development of high-voltage pulse generator with variable amplitude and duration

    Science.gov (United States)

    Upadhyay, J.; Sharma, M. L.; Ahuja, Aakash B.; Navathe, C. P.

    2014-06-01

    A high voltage pulse generator with variable amplitude (100-3000 V) and duration (100-2000 μs) has been designed and developed. The variable duration pulse has been generated by adopting a simple and novel technique of varying the turn off delay time of a high voltage Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based switch by varying external gate resistance. The pulse amplitude is made variable by adjusting biasing supply of the high voltage switch. The high voltage switch has been developed using a MOSFET based stack of 3 kV rating with switching time of 7 ns.

  7. High Voltage Cable Splicing and Cable Termination Techniques

    Science.gov (United States)

    1976-08-01

    solid dielectric insulations currently used are high-molecular-weight polyethylene (EP) and cross-linked poly- ethylene ( XLPE ). The EP insulation is...rated for 750 C a maximum temperature, and the XLPE insulation is rated for 900C maximum temperature. These insulation materials provide the conductor...The cost of installing PILC with copper conductors is compared to the cost of installing XLPE cable with aluminum conductors in Table 1. The

  8. Matlab/Simulink Modeling of Four-leg Voltage Source Inverter With Fundamental Inverter output Voltages Vector Observation

    Directory of Open Access Journals (Sweden)

    Riyadh G. Omar

    2014-12-01

    Full Text Available Four-leg voltage source inverter is an evolution of the three-leg inverter, and was ought about by the need to handle the non-linear and unbalanced loads. In this work Matlab/ Simulink model is presented using space vector modulation technique. Simulation results for worst conditions of unbalanced linear and non-linear loads are obtained. Observation for the continuity of the fundamental inverter output voltages vector in stationary coordinate is detected for better performance. Matlab programs are executed in block functions to perform switching vector selection and space vector switching.

  9. Over-voltage protection system and method

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Song; Dong, Dong; Lai, Rixin

    2017-05-02

    An over-voltage protection system includes an electronic valve connected across two terminals of a circuit and an over-voltage detection circuit connected across one of the plurality of semiconductor devices for detecting an over-voltage across the circuit. The electronic valve includes a plurality of semiconductor devices connected in series. The over-voltage detection circuit includes a voltage divider circuit connected to a break-over diode in a way to provide a representative low voltage to the break-over diode and an optocoupler configured to receive a current from the break-over diode when the representative low voltage exceeds a threshold voltage of the break-over diode indicating an over-voltage condition. The representative low voltage provided to the break-over diode represents a voltage across the one semiconductor device. A plurality of self-powered gate drive circuits are connected to the plurality of semiconductor devices, wherein the plurality of self-powered gate drive circuits receive over-voltage triggering pulses from the optocoupler during the over-voltage condition and switch on the plurality of semiconductor devices to bypass the circuit.

  10. Effect of Threshold Voltage on Various CMOS Performance Parameter

    Directory of Open Access Journals (Sweden)

    Mr. Abhishek Verma

    2014-04-01

    Full Text Available SiO2, once thought of as the most precious element in the design of CMOS circuits has not lived up to the expectations of being the perfect gate oxide. Efforts have been made to replace it with High K oxides such as Lanthanum Oxide (La2O3, Hafnium Oxide (HfO2 and many more. This review covers the problems faced by the High K oxides, one of them being escalation in threshold voltage which results in increased power dissipation. The solution to the above stated problem is to reduce the threshold voltage by several techniques, also covered in the review. Effect of threshold voltage on leakage current and power and reliability of CMOS are also taken under consideration.

  11. Unequal Input Voltages Distribution Between the Serial Connected Halfbridges

    Directory of Open Access Journals (Sweden)

    Radovan Ovcarcik

    2006-01-01

    Full Text Available This paper describes a topology of DC-DC converter consisting in two serial connected half-bridges. Secondary circuit is realized like a conventional full-wave rectifier. The main advantage of this topology is the possibility of dividing the input voltage between the half-bridges. The converter is controlled using the phase-shift modulation, which allows a ZVSoperation mode. The voltage unbalance between the inputs causes an important problem of the presented topology. It is necessary to avoid it by the control algorithm, which is described in the text. The practical results show a zero voltage switching technique and the limits of the chosen topology and of the control.

  12. How cesium dialysis affects the passive properties of pyramidal neurons: implications for voltage clamp studies of persistent sodium current

    Energy Technology Data Exchange (ETDEWEB)

    Fleidervish, Ilya A; Libman, Lior [Koret School of Veterinary Medicine, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100 (Israel)], E-mail: fleider@agri.huji.ac.il

    2008-03-15

    In order to accurately understand and model neuronal integration in the brain, we must know the biophysical properties of channels that are located far from the soma, in the axonal and dendritic membranes of central nerve cells. Reliable electrophysiological measurements in these regions are difficult to obtain, because the processes are too tiny to directly study with an electrode. One common strategy is to record with a somatic electrode that contains Cs{sup +}, to dialyze the intracellular space with this K{sup +} channel blocker, and thereby to render the neuron electrotonically compact. Does this work? Here, we combine the experimental and modeling techniques to determine the extent to which a whole-cell voltage clamp, established with a Cs{sup +}-containing pipette in the soma of a cortical pyramidal cell, attains adequate voltage control of distal neuronal processes. We focus on the low-voltage-activated, slowly inactivating 'persistent' Na{sup +} current (I{sub NaP}), that plays a crucial role in determining neuronal excitability and synaptic integration.

  13. How cesium dialysis affects the passive properties of pyramidal neurons: implications for voltage clamp studies of persistent sodium current

    Science.gov (United States)

    Fleidervish, Ilya A.; Libman, Lior

    2008-03-01

    In order to accurately understand and model neuronal integration in the brain, we must know the biophysical properties of channels that are located far from the soma, in the axonal and dendritic membranes of central nerve cells. Reliable electrophysiological measurements in these regions are difficult to obtain, because the processes are too tiny to directly study with an electrode. One common strategy is to record with a somatic electrode that contains Cs+, to dialyze the intracellular space with this K+ channel blocker, and thereby to render the neuron electrotonically compact. Does this work? Here, we combine the experimental and modeling techniques to determine the extent to which a whole-cell voltage clamp, established with a Cs+-containing pipette in the soma of a cortical pyramidal cell, attains adequate voltage control of distal neuronal processes. We focus on the low-voltage-activated, slowly inactivating 'persistent' Na+ current (INaP), that plays a crucial role in determining neuronal excitability and synaptic integration.

  14. A Comparative Study of Ultra-Low Voltage Digital Circuit Design

    Directory of Open Access Journals (Sweden)

    Aaron Arthurs

    2012-07-01

    Full Text Available Ultra-low voltage digital circuit design is an active research area, especially for portable applications such as wearable electronics, intelligent remote sensors, implantable medical devices, and energy-harvesting systems. Due to their application scenarios and circuit components, two major goals for these systems are minimizing energy consumption and improving compatibility with low-voltage power supplies and analog components. The most effective solution to achieve these goals is to reduce the supply voltage, which,however, raises the issue of operability. At ultra-low supply voltages, the integrity of digital signals degrades dramatically due to the indifference between active and leakage currents. In addition, the system timing becomes more unpredictable as the impact of process and supply voltage variations being more significant at lower voltages. This paper presents a comparative study among three techniques for designing digital circuits operating at ultra-low voltages, i.e., Schmitt-triggered gate structure, delayinsensitive asynchronous logic, and Fully-Depleted Silicon-on-Insulator technology. Results show that despite the tradeoffs, all eight combinations of these techniques are viable for designing ultra-low voltage circuits. For a given application, the optimum circuit design can be selected from these combinations based on the lowest voltage, the dynamic range, the power budget, the performance requirement, and the available semiconductor process node.

  15. A Comparative Study of Ultra-Low Voltage Digital Circuit Design

    Directory of Open Access Journals (Sweden)

    Aaron Arthurs,

    2012-06-01

    Full Text Available Ultra-low voltage digital circuit design is an active research area, especially for portable applications such as wearable electronics, intelligent remote sensors, implantable medical devices, and energy-harvesting systems. Due to their application scenarios and circuit components, two major goals for these systems are minimizing energy consumption and improving compatibility with low-voltage power supplies and analog components. The most effective solution to achieve these goals is to reduce the supply voltage, which,however, raises the issue of operability. At ultra-low supply voltages, the integrity of digital signals degrades dramatically due to the indifference between active and leakage currents. In addition, the system timing becomes more unpredictable as the impact of process and supply voltage variations being more significant at lower voltages. This paper presents a comparative study among three techniques for designing digital circuits operating at ultra-low voltages, i.e., Schmitt-triggered gate structure, delay insensitive asynchronous logic, and Fully-Depleted Silicon-on-Insulator technology. Results show that despite the trade offs, all eight combinations of these techniques are viable for designing ultra-low voltage circuits. For a given application, the optimum circuit design can be selected from these combinations based on the lowest voltage, the dynamic range, the power budget, the performance requirement, and the available semiconductor process node.

  16. Advances in high voltage engineering

    CERN Document Server

    Haddad, A

    2005-01-01

    This book addresses the very latest research and development issues in high voltage technology and is intended as a reference source for researchers and students in the field, specifically covering developments throughout the past decade. This unique blend of expert authors and comprehensive subject coverage means that this book is ideally suited as a reference source for engineers and academics in the field for years to come.

  17. High Voltage Pulse Testing Survey.

    Science.gov (United States)

    1985-10-01

    Cryogenic 23 E. Liquids 26 F. Solids 28 1. Polyethylene 28 2. Cross-Linked Polyethylene ( XLPE ) 29 3. Polyimide and Polyvenylchloride (PVC) 31 VI Benefits 35 A...Strength of XLPE Cables 29 vii * 4" I PROGRAM OBJECTIVES The Pulse Test Survey summarizes government, industry, and technical reports on high voltage pulse...system of silicone oil on a XLPE (cross-linked polyethylene) spacer tends to lower the impulse breakdown by approximately 10 percent. The negative impulse

  18. TRANSISTOR HIGH VOLTAGE POWER SUPPLY

    Science.gov (United States)

    Driver, G.E.

    1958-07-15

    High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

  19. Low voltage electron beam accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ochi, Masafumi [Iwasaki Electric Co., Ltd., Tokyo (Japan)

    2003-02-01

    Widely used electron accelerators in industries are the electron beams with acceleration voltage at 300 kV or less. The typical examples are shown on manufactures in Japan, equipment configuration, operation, determination of process parameters, and basic maintenance requirement of the electron beam processors. New electron beam processors with acceleration voltage around 100 kV were introduced maintaining the relatively high dose speed capability of around 10,000 kGy x mpm at production by ESI (Energy Science Inc. USA, Iwasaki Electric Group). The application field like printing and coating for packaging requires treating thickness of 30 micron or less. It does not require high voltage over 110 kV. Also recently developed is a miniature bulb type electron beam tube with energy less than 60 kV. The new application area for this new electron beam tube is being searched. The drive force of this technology to spread in the industries would be further development of new application, process and market as well as the price reduction of the equipment, upon which further acknowledgement and acceptance of the technology to societies and industries would entirely depend. (Y. Tanaka)

  20. Simultaneously propagating voltage and pressure pulses in lipid monolayers of pork brain and synthetic lipids

    Science.gov (United States)

    Griesbauer, J.; Bössinger, S.; Wixforth, A.; Schneider, M. F.

    2012-12-01

    Hydrated interfaces are ubiquitous in biology and appear on all length scales from ions and individual molecules to membranes and cellular networks. In vivo, they comprise a high degree of self-organization and complex entanglement, which limits their experimental accessibility by smearing out the individual phenomenology. The Langmuir technique, however, allows the examination of defined interfaces, the controllable thermodynamic state of which enables one to explore the proper state diagrams. Here we demonstrate that voltage and pressure pulses simultaneously propagate along monolayers comprised of either native pork brain or synthetic lipids. The excitation of pulses is conducted by the application of small droplets of acetic acid and monitored subsequently employing time-resolved Wilhelmy plate and Kelvin probe measurements. The isothermal state diagrams of the monolayers for both lateral pressure and surface potential are experimentally recorded, enabling us to predict dynamic voltage pulse amplitudes of 0.1-3 mV based on the assumption of static mechanoelectrical coupling. We show that the underlying physics for such propagating pulses is the same for synthetic and natural extracted (pork brain) lipids and that the measured propagation velocities and pulse amplitudes depend on the compressibility of the interface. Given the ubiquitous presence of hydrated interfaces in biology, our experimental findings seem to support a fundamentally new mechanism for the propagation of signals and communication pathways in biology (signaling), which is based neither on protein-protein or receptor-ligand interaction nor diffusion.

  1. Synchronization analysis of voltage-sensitive dye imaging during focal seizures in the rat neocortex

    Science.gov (United States)

    Takeshita, Daisuke; Bahar, Sonya

    2011-12-01

    Seizures are often assumed to result from an excess of synchronized neural activity. However, various recent studies have suggested that this is not necessarily the case. We investigate synchronization during focal neocortical seizures induced by injection of 4-aminopyridine (4AP) in the rat neocortex in vivo. Neocortical activity is monitored by field potential recording and by the fluorescence of the voltage-sensitive dye RH-1691. After removal of artifacts, the voltage-sensitive dye (VSD) signal is analyzed using the nonlinear dynamics-based technique of stochastic phase synchronization in order to determine the degree of synchronization within the neocortex during the development and spread of each seizure event. Results show a large, statistically significant increase in synchronization during seizure activity. Synchrony is typically greater between closer pixel pairs during a seizure event; the entire seizure region is synchronized almost exactly in phase. This study represents, to our knowledge, the first application of synchronization analysis methods to mammalian VSD imaging in vivo. Our observations indicate a clear increase in synchronization in this model of focal neocortical seizures across a large area of the neocortex; a sharp increase in synchronization during seizure events was observed in all 37 seizures imaged. The results are consistent with a recent computational study which simulates the effect of 4AP in a neocortical neuron model.

  2. Low-Driving-Voltage Optical Modulation Utilizing FWM for High-Speed Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    Akihiko; Matsuura; Toshiya; Matsuda; Tomoyoshi; Kataoka

    2003-01-01

    We propose an optical transmitter with reduced modulator driving voltage. This reduction is achieved through an on-off ratio improvement technique based on FWM. We confirmed the feasibility of the method in a 43-Gbit/s experiment.

  3. Phenological Records

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Phenology is the scientific study of periodic biological phenomena, such as flowering, breeding, and migration, in relation to climatic conditions. The few records...

  4. Relación céntrica: revisión de conceptos y técnicas para su registro. Parte II Centric relation: concepts revision and recording techniques. Part II

    Directory of Open Access Journals (Sweden)

    A. Orozco Varo

    2008-12-01

    Full Text Available La relación céntrica ha sido objeto de disparidad de criterios en la odontología durante más de un siglo. A lo largo de este trabajo, vamos a exponer diferentes métodos usados tanto para obtener el registro, como para comprobar su certeza y corroborar la posición condilar. Dado que no existe evidencia científica en el tema, en este trabajo, revisaremos los estudios experimentales que aparecen en la literatura. Los hemos divididos en dos partes, la primera relacionada con la definición de relación céntrica y la segunda parte relacionada con técnicas de registro, posición condilar y la discrepancia entre relación céntrica y oclusión céntrica.The centric relation has been controversial on dentistry during more of one century. Along of this work, we are going to expose different methods to recording as checking the accuracy and condilar position. Given that there aren’t scientific evidence, in this work, we review the researches publicated. We have divided them into two parts; the first is related with the definition of centric relation and the second part is related with recording techniques, condilar position and centric relation- centric occlusion discrepancy.

  5. Relación céntrica: revisión de conceptos y técnicas para su registro. Parte I Centric relation: concepts revision and recording techniques. Part I

    Directory of Open Access Journals (Sweden)

    A. Orozco Varo

    2008-12-01

    Full Text Available La relación céntrica ha sido objeto de disparidad de criterios en la odontología durante más de un siglo. A lo largo de este trabajo, vamos a exponer diferentes métodos usados tanto para obtener el registro, como para comprobar su certeza y corroborar la posición condilar. Dado que no existe evidencia científica en el tema, en este trabajo, revisaremos los estudios experimentales que aparecen en la literatura. Los hemos divididos en dos partes, la primera relacionada con la definición de relación céntrica y la segunda parte relacionada con técnicas de registro, posición condilar y la discrepancia entre relación céntrica y oclusión céntrica.The centric relation has been controversial on dentistry during more of one century. Along of this work, we are going to expose different methods to recording as checking the accuracy and condilar position. Given that there aren’t scientific evidence, in this work, we review the researches publicated. We have divided them into two parts; the first is related with the definition of centric relation and the second part is related with recording techniques, condilar position and centric relation- centric occlusion discrepancy.

  6. Piezo Voltage Controlled Planar Hall Effect Devices

    OpenAIRE

    Bao Zhang; Kang-Kang Meng; Mei-Yin Yang; Edmonds, K. W.; Hao Zhang; Kai-Ming Cai; Yu Sheng; Nan Zhang; Yang Ji; Jian-Hua Zhao; Hou-Zhi Zheng; Kai-You Wang

    2015-01-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the pie...

  7. A new technique for recording interocclusal contacts

    OpenAIRE

    2005-01-01

    Resumo: A influência dos contatos oclusais na dinâmica das articulações temporomandibulares e tonicidade dos musculos mastigatórios tem sido constatada em várias pesquisas. A harmonia entre esses componentes do sistema mastigatório só será obtida, se os contatos que ocorrem na superfície oclusal dos dentes, quer sejam no término do fechamento ou durante as excursões da mandíbula, forem identificados de forma precisa. Atualmente, existem vários materiais e técnicas para atender esta necessidad...

  8. The effect of providing feedback on inhaler technique and adherence from an electronic audio recording device, INCA®, in a community pharmacy setting: study protocol for a randomised controlled trial.

    Science.gov (United States)

    O'Dwyer, Susan Mary; MacHale, Elaine; Sulaiman, Imran; Holmes, Martin; Hughes, Cian; D'Arcy, Shona; Rapcan, Viliam; Taylor, Terence; Boland, Fiona; Bosnic-Anticevich, Sinthia; Reilly, Richard B; Ryder, Sheila A; Costello, Richard W

    2016-05-04

    Poor adherence to inhaled medication may lead to inadequate symptom control in patients with respiratory disease. In practice it can be difficult to identify poor adherence. We designed an acoustic recording device, the INCA® (INhaler Compliance Assessment) device, which, when attached to an inhaler, identifies and records the time and technique of inhaler use, thereby providing objective longitudinal data on an individual's adherence to inhaled medication. This study will test the hypothesis that providing objective, personalised, visual feedback on adherence to patients in combination with a tailored educational intervention in a community pharmacy setting, improves adherence more effectively than education alone. The study is a prospective, cluster randomised, parallel-group, multi-site study conducted over 6 months. The study is designed to compare current best practice in care (i.e. routine inhaler technique training) with the use of the INCA® device for respiratory patients in a community pharmacy setting. Pharmacies are the unit of randomisation and on enrolment to the study they will be allocated by the lead researcher to one of the three study groups (intervention, comparator or control groups) using a computer-generated list of random numbers. Given the nature of the intervention neither pharmacists nor participants can be blinded. The intervention group will receive feedback from the acoustic recording device on inhaler technique and adherence three times over a 6-month period along with inhaler technique training at each of these times. The comparator group will also receive training in inhaler use three times over the 6-month study period but no feedback on their habitual performance. The control group will receive usual care (i.e. the safe supply of medicines and advice on their use). The primary outcome is the rate of participant adherence to their inhaled medication, defined as the proportion of correctly taken doses of medication at the correct

  9. Investigation of Shaft Voltage in Wind Turbine Systems with Induction Generators

    Science.gov (United States)

    Adabi, Jafar; Zare, Firuz

    This paper presents the analysis of shaft voltage in different configurations of a doubly fed induction generator (DFIG) and an induction generator (IG) with a back-to-back inverter in wind turbine applications. Detailed high frequency model of the proposed systems have been developed based on existing capacitive couplings in IG & DFIG structures and common mode voltage sources. In this research work, several arrangements of DFIG based wind energy conversion systems (WES) are investigated in case of shaft voltage calculation and its mitigation techniques. Placements of an LC line filter in different locations and its effects on shaft voltage elimination are studied via Mathematical analysis and simulations. A pulse width modulation (PWM) technique and a back-to-back inverter with a bidirectional buck converter have been presented to eliminate the shaft voltage in a DFIG wind turbine.

  10. On-chip high-voltage generator design design methodology for charge pumps

    CERN Document Server

    Tanzawa, Toru

    2016-01-01

    This book provides various design techniques for switched-capacitor on-chip high-voltage generators, including charge pump circuits, regulators, level shifters, references, and oscillators.  Readers will see these techniques applied to system design in order to address the challenge of how the on-chip high-voltage generator is designed for Flash memories, LCD drivers, and other semiconductor devices to optimize the entire circuit area and power efficiency with a low voltage supply, while minimizing the cost.  This new edition includes a variety of useful updates, including coverage of power efficiency and comprehensive optimization methodologies for DC-DC voltage multipliers, modeling of extremely low voltage Dickson charge pumps, and modeling and optimum design of AC-DC switched-capacitor multipliers for energy harvesting and power transfer for RFID.

  11. Simultaneous measurement of membrane potential changes in multiple pattern generating neurons using voltage sensitive dye imaging.

    Science.gov (United States)

    Städele, Carola; Andras, Peter; Stein, Wolfgang

    2012-01-15

    Optical imaging using voltage-sensitive dyes (VSDs) is a promising technique for the simultaneous activity recording of many individual neurons. While such simultaneous recordings are critical for the understanding of the integral functionality of neural systems, functional interpretations on a single neuron level are difficult without knowledge of the connectivity of the underlying circuit. Central pattern generating circuits, such as the pyloric and gastric mill circuits in the stomatogastric ganglion (STG) of crustaceans, allow such investigations due to their well-known connectivities and have already contributed much to our understanding of general neuronal mechanisms. Here we present for the first time simultaneous optical recordings of the pattern generating neurons in the STG of two crustacean species using bulk loading of the VSD di-4-ANEPPS. We demonstrate the recording of firing activities and synaptic interactions of the circuit neurons as well as inter-circuit interactions in their functional context, i.e. without artificial stimulation. Neurons could be uniquely identified using simple event-triggered averaging. We tested this technique in two different species of crustaceans (lobsters and crabs), since several crustacean species are used for studying motor pattern generation. The signal-to-noise ratio of the optical signal was high enough in both species to derive phase-relationship between the network neurons, as well as action potentials and excitatory and inhibitory postsynaptic potentials. We argue that imaging of neural networks with identifiable neurons with well-known connectivity, like in the STG, is crucial for the understanding of emergence of network functionality.

  12. 49 CFR 234.221 - Lamp voltage.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Lamp voltage. 234.221 Section 234.221 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., Inspection, and Testing Maintenance Standards § 234.221 Lamp voltage. The voltage at each lamp shall...

  13. Bootstrapped Low-Voltage Analog Switches

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1999-01-01

    Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...

  14. A Stochastic Response Surface Method for Probabilistic Evaluation of the Voltage Stability Considering Wind Power

    Institute of Scientific and Technical Information of China (English)

    BAO Haibo; WEI Hua

    2012-01-01

    The traditional voltage stability analysis method is mostly based on the deterministic model, and ignores the uncertainties of bus loads, power supplies, changes in network configuration and so on. However, the great expansion of renewable power generations such as wind and solar energy in a power system has increased their uncertainty, and traditional techniques are limited in capturing their variable behavior. This leads to greater needs of new techniques and methodologies to properly quantify the voltage stability of power systems.

  15. Deletion of cytosolic gating ring decreases gate and voltage sensor coupling in BK channels.

    Science.gov (United States)

    Zhang, Guohui; Geng, Yanyan; Jin, Yakang; Shi, Jingyi; McFarland, Kelli; Magleby, Karl L; Salkoff, Lawrence; Cui, Jianmin

    2017-03-06

    Large conductance Ca(2+)-activated K(+) channels (BK channels) gate open in response to both membrane voltage and intracellular Ca(2+) The channel is formed by a central pore-gate domain (PGD), which spans the membrane, plus transmembrane voltage sensors and a cytoplasmic gating ring that acts as a Ca(2+) sensor. How these voltage and Ca(2+) sensors influence the common activation gate, and interact with each other, is unclear. A previous study showed that a BK channel core lacking the entire cytoplasmic gating ring (Core-MT) was devoid of Ca(2+) activation but retained voltage sensitivity (Budelli et al. 2013. Proc. Natl. Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1313433110). In this study, we measure voltage sensor activation and pore opening in this Core-MT channel over a wide range of voltages. We record gating currents and find that voltage sensor activation in this truncated channel is similar to WT but that the coupling between voltage sensor activation and gating of the pore is reduced. These results suggest that the gating ring, in addition to being the Ca(2+) sensor, enhances the effective coupling between voltage sensors and the PGD. We also find that removal of the gating ring alters modulation of the channels by the BK channel's β1 and β2 subunits.

  16. A New Low Voltage P-MOS Bulk Driven Current Mirror Circuit

    Directory of Open Access Journals (Sweden)

    Anuj Dugaya

    2013-08-01

    Full Text Available This work proposes a new low voltage current mirror circuit using bulk driven technique. Bulk driventechnique is used to reduce the threshold of PMOS used in low voltage current mirror circuits (LVCM.TheProposed circuit consist of 4 PMOS and 5 NMOS. The proposed circuit operated at +0.85 V supplyvoltage.The bandwidth of this circuit has also been enhanced using resistive compensation technique. Theproposed circuit has been simulated in Cadence Design Environment in UMC 180nm CMOS technology. Atransfer characteristic of the proposed circuit has been discussed. The proposed circuit find application inlow voltage and low power analog integrated circuits.

  17. Voltage Control Scheme for Three Phase SVM Inverter Fed Induction Motor Drive Systems

    Directory of Open Access Journals (Sweden)

    U. SOWMMIYA

    2010-12-01

    Full Text Available This paper presents an efficient implementation scheme for the closed-loop voltage control of an induction motor incorporating ‘Space Vector Pulse Width Modulation (SVPWM‘. Voltage control is required to meet the variation in the input voltage and to regulate the output of the inverter. Space Vector Modulation (SVM is an algorithm for the control of Pulse Width Modulation (PWM. Comparative study has been made between SVM and PWM techniques. From the simulation results, SVM has reduced THD compared to pulse width modulation techniques. Thus, SVM gives better harmonic response and higher efficiency.

  18. Voltage Management in Unbalanced Low Voltage Networks Using a Decoupled Phase-Tap-Changer Transformer

    DEFF Research Database (Denmark)

    Coppo, Massimiliano; Turri, Roberto; Marinelli, Mattia

    2014-01-01

    The paper studies a medium voltage-low voltage transformer with a decoupled on load tap changer capability on each phase. The overall objective is the evaluation of the potential benefits on a low voltage network of such possibility. A realistic Danish low voltage network is used for the analysis...

  19. Estimating Voltage Asymmetry Making by One Phase Micro-generator in Low Voltage Network

    Directory of Open Access Journals (Sweden)

    Marian Sobierajski

    2014-12-01

    Full Text Available Connection of one phase micro-generator to the low voltage network increases voltage asymmetry. The voltage asymmetry is defined as the quotient of negative and positive voltage components. The mathematical background of exact and rough computation of the asymmetry quotient is presented in the paper. Considerations are illustrated by simple examples.

  20. 76 FR 70721 - Voltage Coordination on High Voltage Grids; Notice of Staff Workshop

    Science.gov (United States)

    2011-11-15

    ... Energy Regulatory Commission Voltage Coordination on High Voltage Grids; Notice of Staff Workshop Take notice that the Federal Energy Regulatory Commission will hold a Workshop on Voltage Coordination on High Voltage Grids on Thursday, December 1, 2011 from 9 a.m. to 4:30 p.m. This staff-led workshop will be...

  1. Improving transition voltage spectroscopy of molecular junctions

    DEFF Research Database (Denmark)

    Markussen, Troels; Chen, Jingzhe; Thygesen, Kristian Sommer

    2011-01-01

    Transition voltage spectroscopy (TVS) is a promising spectroscopic tool for molecular junctions. The principles in TVS is to find the minimum on a Fowler-Nordheim plot where ln(I/V2) is plotted against 1/V and relate the voltage at the minimum Vmin to the closest molecular level. Importantly, Vmin...... is approximately half the voltage required to see a peak in the dI/dV curve. Information about the molecular level position can thus be obtained at relatively low voltages. In this work we show that the molecular level position can be determined at even lower voltages, Vmin(α), by finding the minimum of ln...

  2. Piezo Voltage Controlled Planar Hall Effect Devices

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K. W.; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  3. Piezo Voltage Controlled Planar Hall Effect Devices.

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-22

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

  5. Voltage-Sensitive Load Controllers for Voltage Regulation and Increased Load Factor in Distribution Systems

    DEFF Research Database (Denmark)

    Douglass, Philip James; Garcia-Valle, Rodrigo; Østergaard, Jacob

    2014-01-01

    consumption which can be mapped to temperature setpoint offsets of thermostat controlled loads. In networks where a lower voltage level corresponds to high system load (and vice versa), this controller acts to regulate voltage and increase the load factor. Simulations are conducted on low- and medium-voltage......This paper presents a novel controller design for controlling appliances based on local measurements of voltage. The controller finds the normalized voltage deviation accounting for the sensitivity of voltage measurements to appliance state. The controller produces a signal indicating desired power...... distribution systems with residential loads including voltage-sensitive water heaters. In low-voltage systems, the results of the simulations show the controller to be effective at reducing the extremes of voltage and increasing the load factor while respecting end-use temperature constraints. In medium-voltage...

  6. Voltage-controlled photonic oscillator.

    Science.gov (United States)

    Savchenkov, A A; Ilchenko, V S; Liang, W; Eliyahu, D; Matsko, A B; Seidel, D; Maleki, L

    2010-05-15

    We report the development and demonstration of an X-band voltage-controlled photonic oscillator based on a whispering gallery mode resonator made of an electro-optic crystalline material. The oscillator has good spectral purity and wide, agile, linear tunability. We have modified the existing theoretical model of the opto-electronic oscillator to describe the performance of our tunable oscillator and have found a good agreement between the theoretical predictions and the measurement results. We show that the device is promising for higher-frequency applications where high-performance tunable oscillators with wide tunability do not exist.

  7. Low voltage substrate current: a monitor for interface states generation in ultra-thin oxide n-MOSFETs under constant voltage stresses

    Institute of Scientific and Technical Information of China (English)

    Wang Yan-Gang; Xu Ming-Zhen; Tan Chang-Hua

    2007-01-01

    The low voltage substrate current (Ib) has been studied based on generation kinetics and used as a monitor of interface states (Nit) generation for ultra-thin oxide n-MOSFETs under constant voltage stress. It is found that the low voltage Ib is formed by electrons tunnelling through interface states, and the variations of Ib(△Ib) are proportional to variations of Nit (△Nit). The Nit energy distributions were determined by differentiating Nit(Vg). The results have been compared with that measured by using gate diode technique.

  8. Voltage Management in Unbalanced Low Voltage Networks Using a Decoupled Phase-Tap-Changer Transformer

    OpenAIRE

    Coppo, Massimiliano; Turri, Roberto; Marinelli, Mattia; Han, Xue

    2014-01-01

    The paper studies a medium voltage-low voltage transformer with a decoupled on load tap changer capability on each phase. The overall objective is the evaluation of the potential benefits on a low voltage network of such possibility. A realistic Danish low voltage network is used for the analysis. The load profiles are characterized by using single phase measurement data on voltages, currents and active powers with a 10 minutes resolution. Different scenarios are considered: no tap action, th...

  9. Modelling and application of modern control techniques to governor and voltage regulator systems of synchronous machines of small hydroelectric power plants; Modelagem e aplicacao de tecnicas de controle moderno a sistemas reguladores de velocidade e tensao de maquinas sincronas de pequenas centrais hidreletricas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Claudio Homero Ferreira da

    2002-07-01

    In small hydroelectric plants the control system is quite simplified. It is sometimes mounted in a primitive and archaic way although it is functional. Performance of this system determines the final quality of the energy, stability and physical integrity of the apparatus as well as the whole electric system. Based on the present situation of the electric system, it is noticed a tendency in building and modernizing early small hydroelectric plants in order to increase energy supply very fast with low cost and satisfying environmental constraints. The development of mathematical tools and digital computer facilities have made possible the use of advanced automatic control structures that take into account the process stability even in presence of noise measurement and plant/model mismatch. Physical modifications in the plant are proposed in order to provide significant improvement in closed loop behaviour of the turbine speed and terminal voltage control. The decision ability and flexibility of the computer package to be developed are the major aspects that support this research. It will be intended to incorporate this control computer package into programmable logical controller. Experimental data from CEMIG's Martins Hydro Plant (4 x 2750 KVA), located in Uberlandia, Brazil, were used to identify and validate the system model. Pole placement, optimal control and model predictive control techniques were used to controller design. Perfect modeling and plant/model mismatch were considered in both presence and absence of state observers (full order and reduced order) in order to become accessible unmeasured states. Simulation results show developed controllers are promising for the system regulating. The proposed approaches offer a larger control flexibility taking into account plant/model mismatch and stability questions. These results contribute to a quality energy improvement associated to a cost reduction in energy generation process. (author)

  10. Particle swarm optimization for determining shortest distance to voltage collapse

    Energy Technology Data Exchange (ETDEWEB)

    Arya, L.D.; Choube, S.C. [Electrical Engineering Department, S.G.S.I.T.S. Indore, MP 452 003 (India); Shrivastava, M. [Electrical Engineering Department, Government Engineering College Ujjain, MP 456 010 (India); Kothari, D.P. [Centre for Energy Studies, Indian Institute of Technology, Delhi (India)

    2007-12-15

    This paper describes an algorithm for computing shortest distance to voltage collapse or determination of CSNBP using PSO technique. A direction along CSNBP gives conservative results from voltage security view point. This information is useful to the operator to steer the system away from this point by taking corrective actions. The distance to a closest bifurcation is a minimum of the loadability given a slack bus or participation factors for increasing generation as the load increases. CSNBP determination has been formulated as an optimization problem to be used in PSO technique. PSO is a new evolutionary algorithm (EA) which is population based inspired by the social behavior of animals such as fish schooling and birds flocking. It can handle optimization problems with any complexity since mechanization is simple with few parameters to be tuned. The developed algorithm has been implemented on two standard test systems. (author)

  11. Student Records

    Science.gov (United States)

    Fields, Cheryl

    2005-01-01

    Another topic involving privacy has attracted considerable attention in recent months--the "student unit record" issue. The U.S. Department of Education concluded in March that it would be feasible to help address lawmakers' concerns about accountability in higher education by constructing a database capable of tracking students from institution…

  12. Record dynamics

    DEFF Research Database (Denmark)

    Robe, Dominic M.; Boettcher, Stefan; Sibani, Paolo

    2016-01-01

    -facto irreversible and become increasingly harder to achieve. Thus, a progression of record-sized dynamical barriers are traversed in the approach to equilibration. Accordingly, the statistics of the events is closely described by a log-Poisson process. Originally developed for relaxation in spin glasses...

  13. A New Low Voltage P-MOS Bulk Driven Current Mirror Circuit

    Directory of Open Access Journals (Sweden)

    Anuj Dugaya

    2013-08-01

    Full Text Available This work proposes a new low voltage current mirror circuit using bulk driven technique. Bulk driven technique is used to reduce the threshold of PMOS u sed in low voltage current mirror circuits (LVCM.T he Proposed circuit consist of 4 PMOS and 5 NMOS. The proposed circuit operated at +0.85 V supply voltage.The bandwidth of this circuit has also been enhanced using resistive compensation technique. T he proposed circuit has been simulated in Cadence Desi gn Environment in UMC 180nm CMOS technology. A transfer characteristic of the proposed circuit has been discussed. The proposed circuit find applicat ion in low voltage and low power analog integrated circuit s.

  14. Interpretation on Partial Discharge of Typical Insulation Model Under Oscillating Impulse Voltage

    Institute of Scientific and Technical Information of China (English)

    SUN Zhenquan; ZHAO Xuefeng; LI Jisheng; LI Yanming

    2012-01-01

    The aim of this paper was to give an overview on partial discharges under oscillating impulse voltage.Three models(void in solid,needle-plate in air and oil) were presented,which describe the stochastic discharge process and represent internal discharges in solids and corona in air or silicon oil.Moreover,an air cored Rogowski coil and a sampling resistor for partial discharge(PD) measurement were developed and introduced in this paper.PD inception and extinction voltages(PDIV,PDEV) under single oscillating impulse voltage and AC voltage were investigated with different test samples.Experimental results firstly revealed that the PD inception voltage(PDIV) decreased with increasing applied voltage;secondly the PD inception voltage for three different insulating materials,showed an escalating trend with increasing frequency of the applied voltage.It was proven that the characteristics of PD under oscillating impulse voltage were identical to the features under AC voltage,which could be measured with the phase resolved partial discharge analysis(PRPDA) technique.Based on the reorganization and analysis of PDs under oscillating impulse voltage,the information about insulation defects was extracted from the measured data and used for estimating the risk of insulation failure of the equipment.

  15. Portable EGG recording system based on a digital voice recorder.

    Science.gov (United States)

    Jang, J-K; Shieh, M-J; Kuo, T-S; Jaw, F-S

    2009-01-01

    Cutaneous electrogastrogram (EGG) recording offers the benefit of non-invasive gastrointestinal diagnosis. With long-term ambulatory recording of signals, researchers and clinicians could have more opportunities to investigate and analyse paroxysmal or acute symptoms. A portable EGG system based on a digital voice recorder (DVR) is designed for long-term recording of cutaneous EGG signals. The system consists of electrodes, an EGG amplifier, a modulator, and a DVR. Online monitoring and off-line acquisition of EGG are handled by software. A special design employing an integrated timer circuit is used to modulate the EGG frequency to meet the input requirements of the DVR. This approach involves low supply voltage and low power consumption. Software demodulation is used to simplify the complexity of the system, and is helpful in reducing the size of the portable device. By using surface-mount devices (SMD) and a low-power design, the system is robust, compact, and suitable for long-term portable recording. As a result, researchers can record an ambulatory EGG signal by means of the proposed circuits in conjunction with an up-to-date voice-recording device.

  16. Determination of perpendicular magnetic anisotropy in ultrathin ferromagnetic films by extraordinary Hall voltage measurement.

    Science.gov (United States)

    Moon, Kyoung-Woong; Lee, Jae-Chul; Choe, Sug-Bong; Shin, Kyung-Ho

    2009-11-01

    A magnetometric technique for detecting the magnetic anisotropy field of ferromagnetic films is described. The technique is based on the extraordinary Hall voltage measurement with rotating the film under an external magnetic field. By analyzing the angle-dependent Hall voltage based on the Stoner-Wohlfarth theory, the magnetic anisotropy field is uniquely determined. The present technique is pertinent especially for ultrathin films with strong intrinsic signal, in contrast to the conventional magnetometric techniques of which the signal is in proportion to the sample volume and geometry.

  17. Experimental observation of direct current voltage-induced phase synchronization

    Indian Academy of Sciences (India)

    Haihong Li; Weiqing Liu; Qiongling Dai; Jinghua Xiao

    2006-09-01

    The dynamics of two uncoupled distinct Chua circuits driven by a common direct current voltage is explored experimentally. It was found that, with increasing current intensity, the dominant frequencies of these two Chua circuits will first vary at different speeds, approach an identical value for a certain current intensity and then separate. Techniques such as synchronization index and phase difference distribution were employed to analyze the phase coherence between these two Chua circuits.

  18. Antiferromagentic resonance detected by direct current voltages in MnF{sub 2}/Pt bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Philipp, E-mail: philipp.ross.13@ucl.ac.uk [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Schreier, Michael, E-mail: michael.schreier@wmi.badw.de; Lotze, Johannes [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, Technische Universität München, Garching (Germany); Huebl, Hans; Goennenwein, Sebastian T. B. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Nanosystems Initiative Munich, Munich (Germany); Gross, Rudolf [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, Technische Universität München, Garching (Germany); Nanosystems Initiative Munich, Munich (Germany)

    2015-12-21

    We performed coplanar waveguide-based broadband ferromagnetic resonance experiments on the antiferromagnetic insulator MnF{sub 2}, while simultaneously recording the DC voltage arising in a thin platinum film deposited onto the MnF{sub 2}. The antiferromagnetic resonance is clearly reflected in both the transmission through the waveguide as well as the DC voltage in the Pt strip. The DC voltage remains largely unaffected by field reversal and thus presumably stems from microwave rectification and/or heating effects. However, we identify a small magnetic field orientation dependent contribution, compatible with antiferromagnetic spin pumping theory.

  19. 49 CFR 236.551 - Power supply voltage; requirement.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Power supply voltage; requirement. 236.551 Section... supply voltage; requirement. The voltage of power supply shall be maintained within 10 percent of rated voltage....

  20. The Series Connected Buck Boost Regulator Concept for High Efficiency Light Weight DC Voltage Regulation

    Science.gov (United States)

    Birchenough, Arthur G.

    2003-01-01

    Improvements in the efficiency and size of DC-DC converters have resulted from advances in components, primarily semiconductors, and improved topologies. One topology, which has shown very high potential in limited applications, is the Series Connected Boost Unit (SCBU), wherein a small DC-DC converter output is connected in series with the input bus to provide an output voltage equal to or greater than the input voltage. Since the DC-DC converter switches only a fraction of the power throughput, the overall system efficiency is very high. But this technique is limited to applications where the output is always greater than the input. The Series Connected Buck Boost Regulator (SCBBR) concept extends partial power processing technique used in the SCBU to operation when the desired output voltage is higher or lower than the input voltage, and the implementation described can even operate as a conventional buck converter to operate at very low output to input voltage ratios. This paper describes the operation and performance of an SCBBR configured as a bus voltage regulator providing 50 percent voltage regulation range, bus switching, and overload limiting, operating above 98 percent efficiency. The technique does not provide input-output isolation.

  1. Electrical Recording of Mechanoreceptor Activity.

    Science.gov (United States)

    Kammer, Ann E.

    1978-01-01

    Describes a laboratory experiment designed to give beginning physiology students a successful experience with neurophysiological Techniques and to demonstrate some properties of sensory neurons. Pin electrodes are used to record extracellularly from mechanoreceptors in a cockroach leg. (Author/MA)

  2. Voltage Unbalance Compensation with Smart Three-phase Loads

    DEFF Research Database (Denmark)

    Douglass, Philip; Trintis, Ionut; Munk-Nielsen, Stig

    2016-01-01

    voltage, but it does not reduce the negative sequence voltage. The controller that uses phase-phase voltage as input eliminates negative sequence voltage, and reduces voltage deviations from the average to approximately half their initial value. Current unbalance is reduced when the voltage unbalance...... is caused by asymmetrical loads. These results suggest that the optimal algorithm to reduce system unbalance depends on which system parameter is most important: phase-neutral voltage unbalance, phase-phase voltage unbalance, or current unbalance....

  3. Electric characterization of GaAs deposited on porous silicon by electrodeposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Lajnef, M., E-mail: Mohamed.lajnef@yahoo.fr [Laboratoire de Photovoltaique et de Semi-conducteurs, Centre de Recherche et des Technologies de l' Energie, BP. 95, Hammam-Lif 2050 (Tunisia); Chtourou, R.; Ezzaouia, H. [Laboratoire de Photovoltaique et de Semi-conducteurs, Centre de Recherche et des Technologies de l' Energie, BP. 95, Hammam-Lif 2050 (Tunisia)

    2010-03-01

    GaAs thin films were synthesized on porous Si substrate by the electrodeposition technique. The X-ray diffraction studies showed that the as-grown films were crystallised in mixed phase nature orthorhombic and cubic of GaAs. The GaAs film was then electrically characterized using current-voltage (I-V) and capacitance-voltage (C-V) techniques by the way of Al/GaAs Schottky junctions. The electric analysis allowed us to determine the n factor and the barrier height {phi}{sub b0} parameters of Al/GaAs Schottky junctions. The (C-V) characteristics were recorded at frequency signal 1 MHz in order to identify the effect of the surface states on the behaviour of the capacitance of the device.

  4. Power conditioning using dynamic voltage restorers under different voltage sag types

    Directory of Open Access Journals (Sweden)

    Ahmed M. Saeed

    2016-01-01

    Full Text Available Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs. By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to correct any disturbance affecting a sensitive load voltage. In this paper, modelling of DVR for voltage correction using MatLab software is presented. The performance of the device under different voltage sag types is described, where the voltage sag types are introduced using the different types of short-circuit faults included in the environment of the MatLab/Simulink package. The robustness of the proposed device is evaluated using the common voltage sag indices, while taking into account voltage and current unbalance percentages, where maintaining the total harmonic distortion percentage of the load voltage within a specified range is desired. Finally, several simulation results are shown in order to highlight that the DVR is capable of effective correction of the voltage sag while minimizing the grid voltage unbalance and distortion, regardless of the fault type.

  5. Power conditioning using dynamic voltage restorers under different voltage sag types.

    Science.gov (United States)

    Saeed, Ahmed M; Abdel Aleem, Shady H E; Ibrahim, Ahmed M; Balci, Murat E; El-Zahab, Essam E A

    2016-01-01

    Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs). By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to correct any disturbance affecting a sensitive load voltage. In this paper, modelling of DVR for voltage correction using MatLab software is presented. The performance of the device under different voltage sag types is described, where the voltage sag types are introduced using the different types of short-circuit faults included in the environment of the MatLab/Simulink package. The robustness of the proposed device is evaluated using the common voltage sag indices, while taking into account voltage and current unbalance percentages, where maintaining the total harmonic distortion percentage of the load voltage within a specified range is desired. Finally, several simulation results are shown in order to highlight that the DVR is capable of effective correction of the voltage sag while minimizing the grid voltage unbalance and distortion, regardless of the fault type.

  6. ATLAS Recordings

    CERN Multimedia

    Steven Goldfarb; Mitch McLachlan; Homer A. Neal

    Web Archives of ATLAS Plenary Sessions, Workshops, Meetings, and Tutorials from 2005 until this past month are available via the University of Michigan portal here. Most recent additions include the Trigger-Aware Analysis Tutorial by Monika Wielers on March 23 and the ROOT Workshop held at CERN on March 26-27.Viewing requires a standard web browser with RealPlayer plug-in (included in most browsers automatically) and works on any major platform. Lectures can be viewed directly over the web or downloaded locally.In addition, you will find access to a variety of general tutorials and events via the portal.Feedback WelcomeOur group is making arrangements now to record plenary sessions, tutorials, and other important ATLAS events for 2007. Your suggestions for potential recording, as well as your feedback on existing archives is always welcome. Please contact us at wlap@umich.edu. Thank you.Enjoy the Lectures!

  7. Voltage- and calcium-dependent motility of saccular hair bundles

    Science.gov (United States)

    Quiñones, Patricia M.; Meenderink, Sebastiaan W. F.; Bozovic, Dolores

    2015-12-01

    Active bundle motility, which is hypothesized to supply feedback for mechanical amplification of signals, is thought to enhance sensitivity and sharpen tuning in vestibular and auditory organs. To study active hair bundle motility, we combined high-speed camera recordings of bullfrog sacculi, which were mounted in a two-compartment chamber, and voltage-clamp of the hair cell membrane potential. Using this paradigm, we measured three types of bundle motions: 1) spontaneous oscillations which can be analyzed to measure the physiological operating range of the transduction channel; 2) a sustained quasi-static movement of the bundle that depends on membrane potential; and 3) a fast, transient and asymmetric movement that resets the bundle position and depends on changes in the membrane potential. These data support a role for both calcium and voltage in the transduction-channel function.

  8. High voltage load resistor array

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Monty Ray [Smithfield, VA

    2005-01-18

    A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

  9. Voltage-Controlled Floating Resistor Using DDCC

    Directory of Open Access Journals (Sweden)

    M. Kumngern

    2011-04-01

    Full Text Available This paper presents a new simple configuration to realize the voltage-controlled floating resistor, which is suitable for integrated circuit implementation. The proposed resistor is composed of three main components: MOS transistor operating in the non-saturation region, DDCC, and MOS voltage divider. The MOS transistor operating in the non-saturation region is used to configure a floating linear resistor. The DDCC and the MOS transistor voltage divider are used for canceling the nonlinear component term of MOS transistor in the non-saturation region to obtain a linear current/voltage relationship. The DDCC is employed to provide a simple summer of the circuit. This circuit offers an ease for realizing the voltage divider circuit and the temperature effect that includes in term of threshold voltage can be compensated. The proposed configuration employs only 16 MOS transistors. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.

  10. Multimeric nature of voltage-gated proton channels.

    Science.gov (United States)

    Koch, Hans P; Kurokawa, Tatsuki; Okochi, Yoshifumi; Sasaki, Mari; Okamura, Yasushi; Larsson, H Peter

    2008-07-01

    Voltage-gated potassium channels are comprised of four subunits, and each subunit has a pore domain and a voltage-sensing domain (VSD). The four pore domains assemble to form one single central pore, and the four individual VSDs control the gate of the pore. Recently, a family of voltage-gated proton channels, such as H(V) or voltage sensor only protein (VSOP), was discovered that contain a single VSD but no pore domain. It has been assumed that VSOP channels are monomeric and contain a single VSD that functions as both the VSD and the pore domain. It remains unclear, however, how a protein that contains only a VSD and no pore domain can conduct ions. Using fluorescence measurements and immunoprecipitation techniques, we show here that VSOP channels are expressed as multimeric channels. Further, FRET experiments on constructs with covalently linked subunits show that VSOP channels are dimers. Truncation of the cytoplasmic regions of VSOP reduced the dimerization, suggesting that the dimerization is caused mainly by cytoplasmic protein-protein interactions. However, these N terminus- and C terminus-deleted channels displayed large proton currents. Therefore, we conclude that even though VSOP channels are expressed mainly as dimers in the cell membrane, single VSOP subunits could function independently as proton channels.

  11. Effect of current-voltage characteristics on plasma reforming

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, N. [Univ. of Science and Technology, Daejeon (Korea, Republic of). Environmental System Engineering; Korea Inst. of Machinery and Materials, Daejeon (Korea, Republic of). Environmental System Research Division; Hur, M.; Kim, K.T.; Kim, S.J.; Song, Y.H. [Korea Inst. of Machinery and Materials, Daejeon (Korea, Republic of). Environmental System Research Division

    2010-07-01

    Studies have shown that the energy costs associated with plasma fuel reforming can vary depending on the type of plasma generation technique. The reasons for the different energy costs, however, are not yet clear, since different types of plasma reactor lead to not only different plasma conditions but also lead to different reaction conditions that is not relevant to plasma, such as gas residence time, heat and mass flow conditions. This paper presented the results of a parametric study on methane partial oxidation which was conducted to determine the optimal operating conditions and geometrical design of an arc jet plasma fuel reformer. The arc reactor used in this study was designed to control various operating parameters such as arc length, gas residence time, and gas mixing. Two different types of power supply were tested, notably one that produced high voltage with low current, and one that produced relatively low voltage and high current. The effects of these different voltage-current characteristics on gas reforming process were analyzed based on methane conversion rates, selectivity of products, and thermal efficiencies. The study showed that the input power but not the voltage plays an important role in the present partial oxidation process. The gas residence time was also found to be an important factor in controlling the reformer process. 10 refs., 8 figs.

  12. Non-contact current and voltage sensing method using a clamshell housing and a ferrite cylinder

    Science.gov (United States)

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

    2016-04-26

    A method of measurement using a detachable current and voltage sensor provides an isolated and convenient technique for to measuring 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. A Study on the step response characteristics in shielded resistor divider for full lightning impulse voltage

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ik Soo; Lee, Hyeong Ho [Korea Electrotehnology Research Institute, Changwon (Korea, Republic of); Cho, Jung Soo; Park, Jung Hoo [Pusan National University, Pusan (Korea, Republic of)

    1996-02-01

    This paper presents the development technology of standard shielded resistor divider for full lightning impulse voltage. The ability of large-capacity power apparatus to withstand lighting stroke is usually evaluated by means of full lightning impulse voltage. Lightning impulse voltage test has been essential to evaluate the insulation performance of electrical power apparatus. Recently international standard (IEC 60) on high voltage measurement techniques is being revised and requests a formal traceability of high voltage measurements. Therefore, general interest for this area has grown considerably during last years, and several international intercomparisons have already completed worldwide, i.e. Europe, Japan, America etc., In this viewpoint, we have also investigated the step response of the standard shielded resistor divider, which satisfies the IEC recommendation. (author). 7 refs., 14 figs., 2 tabs.

  14. High voltage generator circuit with low power and high efficiency applied in EEPROM

    Institute of Scientific and Technical Information of China (English)

    Liu Yan; Zhang Shilin; Zhao Yiqiang

    2012-01-01

    This paper presents a low power and high efficiency high voltage generator circuit embedded in electrically erasable programmable read-only memory (EEPROM).The low power is minimized by a capacitance divider circuit and a regulator circuit using the controlling clock switch technique.The high efficiency is dependent on the zero threshold voltage (Vth) MOSFET and the charge transfer switch (CTS) charge pump.The proposed high voltage generator circuit has been implemented in a 0.35μm EEPROM CMOS process.Measured results show that the proposed high voltage generator circuit has a low power consumption of about 150.48 μW and a higher pumping efficiency (83.3%) than previously reported circuits.This high voltage generator circuit can also be widely used in low-power flash devices due to its high efficiency and low power dissipation.

  15. Programable Driver for Voltage-Controlled Oscillators

    Science.gov (United States)

    Fowler, L. E.; Mcneil, J. A.

    1985-01-01

    Electronically programable read-only memory (EPROM) and digital-to-analog converter provide customized time-varying voltage for frequency modulation. Voltage used to modulate IMPATT oscillator that serves as microwave pump for solid-state maser in low-noise amplifier. EPROM simple to tailor voltage waveform to suit characteristics of given maser. Digital information for waveform programed into EPROM chip; digital-to-analog converter reads information and produces corresponding analog wave. Principle readily adapted to other applications.

  16. Generator of ultrashort megavolt voltage pulses

    CERN Document Server

    Zheltov, K A; Shalimanov, V F

    2002-01-01

    Paper describes approx 3 ns duration and > 1 MW amplitude voltage pulse generator under high-ohmic (approx 450 Ohm) load. Generator comprises pulse transformer with magnetized core, as well as, resonance tuned circuit of high-voltage solenoid and accumulating spaces of a shaping line containing, moreover, spark gap to switch charge in transmitting line. Paper contains the results of voltage measuring in generator basic units

  17. Investigation of pulsed voltage limiters characteristics

    Directory of Open Access Journals (Sweden)

    Karimov A. V.

    2012-06-01

    Full Text Available A new method for measuring the voltage limit is offered. It has been designed to measure high-power pulsed current of voltage limiters. The error of this method is half as much as the error of the known method of direct measurement. The investigation of dependence of power capability of single-crystal and double-crystal voltage limiters and of the pulsed operation time on pulse duration.

  18. Technology to improve catenary voltage stability for a.c. railways; Verfahren zur Verbesserung der Spannungshaltung bei Wechselstrombahnen

    Energy Technology Data Exchange (ETDEWEB)

    Zynovchenko, Andriy [Balfour Beatty Rail GmbH, Offenbach (Germany). Abt. Systemtechnik

    2011-04-15

    Catenary voltage is one of the most important criteria for the design of a railway electrification system. The lowest voltage limits defined by the customer or by EN 50163 and EN 50388 may not be violated. The presented novel technique for improvement of the catenary voltage allows the extension of feeding area of a substation. This makes possible a reduction of the number of substations and enhancement of redundancy grade. (orig.)

  19. Voltage Regulation by Phase Commutation Control Running On FPAA

    Directory of Open Access Journals (Sweden)

    Ckristian. R. Durán-Blanco

    2013-11-01

    Full Text Available In this article we present a control scheme for triggering a SCR-based rectifier circuit. As implementation platform we use a field-programmable-analog-array device (FPAA that allows the development of algorithms for proportional, PID and sliding mode (SMC control techniques. Results show good performance of tested techniques to avoid effects of perturbations over the circuit load, by keeping regulated the output voltage. This suggests the potential use of the proposed technology for applications of reconfigurable hardware in power electronics.

  20. Identification of voltage collapse point in self excited induction generator

    Directory of Open Access Journals (Sweden)

    Kalyanasundaram Rajambal

    2009-10-01

    Full Text Available This paper presents a direct equilibrium tracing method for identifying the voltage collapse point of a self-excitedinduction generator (SEIG without many trials. The technique solves differential and algebraic equations simultaneously toobtain the variables in a single step. The load parameter is also automatically varied during equilibrium tracing and thisreduces the computational time significantly. Comparing the simulation results obtained through conventional iterative procedure shows the effectiveness of the technique. An experimental verification on a 1.5KW induction machine validates the simulation results.

  1. Low-Voltage Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

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

    1999-01-01

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

  2. Characterisation of the VELO High Voltage System

    CERN Document Server

    Rakotomiaramanana, B; Eklund, L

    2008-01-01

    The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; vercation of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence th...

  3. Characterisation of the VELO High Voltage System

    CERN Document Server

    Rakotomiaramanana, B; Parkes, C; Eklund, L

    2008-01-01

    The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; verification of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence...

  4. Microprocessor-controlled, programmable ramp voltage generator

    Energy Technology Data Exchange (ETDEWEB)

    Hopwood, J.

    1978-11-01

    A special-purpose voltage generator has been developed for driving the quadrupole mass filter of a residual gas analyzer. The generator is microprocessor-controlled with desired ramping parameters programmed by setting front-panel digital thumb switches. The start voltage, stop voltage, and time of each excursion are selectable. A maximum of five start-stop levels may be pre-selected for each program. The ramp voltage is 0 to 10 volts with sweep times from 0.1 to 999.99 seconds.

  5. Magnetoelectric voltage coefficients of magnetoelectric composites

    Institute of Scientific and Technical Information of China (English)

    WAN Yong-ping; ZHONG Zheng; QIU Jin-hao

    2006-01-01

    The magnetoelectric(ME) effect of the particulate magnetostrictive/piezoelectric composite was theoretically studied. The dependence of the ME voltage coefficients on the material properties of the magnetostrictive phase was discussed. The permittivity,permeability and the elastic modulus of the magnetostrictive phase generally have obvious influences on the ME voltage coefficients. The magnetostrictive phase with a large permittivity,large permeability or stiffer modulus will respectively contribute to the higher ME voltage coefficients. For a certain kind of piezoelectric matrix,the ME voltage coefficients can be improved to some extent by choosing those magnetostrictive materials with large permittivity,permeability or high elastic modulus.

  6. Maximum permissible voltage of YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)

    2014-06-15

    Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  7. Inductive voltage divider modeling in Matlab

    Science.gov (United States)

    Andreev, S. A.; Kim, V. L.

    2017-01-01

    Inductive voltage dividers have the most appropriate metrological characteristics on alternative current and are widely used for converting physical signals. The model of a double-decade inductive voltage divider was designed with the help of Matlab/Simulink. The first decade is an inductive voltage divider with balanced winding, the second decade is a single-stage inductive voltage divider. In the paper, a new transfer function algorithm was given. The study shows errors and differences that appeared between the third degree reduced model and a twenty degree unreduced model. The obtained results of amplitude error differ no more than by 7 % between the reduced and unreduced model.

  8. Development of a voltage scanner of chopper

    CERN Document Server

    Shen Guan Ren; LiShengLi; WangQuanXing; Wu Long Cheng

    2001-01-01

    Development of voltage sweeper of chopper with CPNG are introduced. Voltage sweeper is one of important key parts of chopper. Two years working prove that it is stable and reliable. Its main technology performance save: sine wave frequency: 750 kHz +- 20 Hz; total distortion: 65 Db; output voltage (V-V): 0->=4000 V; the error7 W; voltage supply: 220V AC +-10%, 50 +- 1 Hz; total power supply: <100W; Work temperature range: 0 - 40 degree; Stability in long time <=1%

  9. Mechanism underlying blockade of voltage-gated calcium channels by agmatine in cultured rat hippocampal neurons

    Institute of Scientific and Technical Information of China (English)

    Jian-quan ZHENG; Xie-chuan WENG; Xiao-dan GAI; Jin LI; Wen-bin XIAO

    2004-01-01

    AIM: To investigate whether agmatine could selectively block a given type of the voltage-gated calcium channels (VGCC) and whether related receptors are involved in the blocking effect of agmatine on VGCC. METHODS: The whole-cell patch recording technique was performed to record VGCC currents in the cultured neonatal rat hippocampal neurons. RESULTS: Verapamil (100 μmol/L), a selective blocker of L-type calcium channel, significantly inhibited VGCC current by 80 %± 7 %. Agmatine (100 μmol/L) could further depress the remained currents by 25 %±6 %. The α2-adrenoceptor antagonist yohimbine (10 μmol/L) and the I2 imidazoline receptor antagonist idazoxon (10 and 40 μmol/L) had no significant effect on VGCC currents when used respectively. When the mixture of yohimbine and agmatine was applied, VGCC currents were still depressed remarkably. However, the blocking effect of agmatine was decreased by 29 %± 8 % in the presence of idazoxon (10 μmol/L). The effect of idazoxon did not increase at a higher concentration (40 μmol/L). CONCLUSION: Agmatine could block the L- and other types of VGCC currents in the cultured rat hippocampal neurons. Blocking effect of agmatine on VGCC was partially related to I2 imidazoline receptor and had no relationship with α2-adrenoceptors.

  10. THE STUDY OF IMPROVING OF STABILITY AND RELIABILITY FOR 250kV HIGH VOLTAGE POWER%改进250kV高压电源稳定性与可靠性的研究

    Institute of Scientific and Technical Information of China (English)

    廖小东; 郑思孝; 刘仲阳; 孙官清; 王培录

    2001-01-01

    The hitches for a ppearing in the high voltage power at 250kV and improvement of the controlling circuit techniques are described. The static high voltage output was exercised by raising the high voltage gradually. The affects between the current load-variety and the vaviety of the input voltoge at + 1096 against the high voltage stability have been obtained. The experiments prove that the high voltage stability have been raised greatly via improving the controlling circuit.

  11. Ion channel recordings on an injection-molded polymer chip.

    Science.gov (United States)

    Tanzi, Simone; Matteucci, Marco; Christiansen, Thomas Lehrmann; Friis, Søren; Christensen, Mette Thylstrup; Garnaes, Joergen; Wilson, Sandra; Kutchinsky, Jonatan; Taboryski, Rafael

    2013-12-21

    In this paper, we demonstrate recordings of the ion channel activity across the cell membrane in a biological cell by employing the so-called patch clamping technique on an injection-molded polymer microfluidic device. The findings will allow direct recordings of ion channel activity to be made using the cheapest materials and production platform to date and with the potential for very high throughput. The employment of cornered apertures for cell capture allowed the fabrication of devices without through holes and via a scheme comprising master origination by dry etching in a silicon substrate, electroplating in nickel and injection molding of the final part. The most critical device parameters were identified as the length of the patching capillary and the very low surface roughness on the inside of the capillary. The cross-sectional shape of the orifice was found to be less critical, as both rectangular and semicircular profiles seemed to have almost the same ability to form tight seals with cells with negligible leak currents. The devices were functionally tested using human embryonic kidney cells expressing voltage-gated sodium channels (Nav1.7) and benchmarked against a commercial state-of-the-art system for automated ion channel recordings. These experiments considered current-voltage (IV) relationships for activation and inactivation of the Nav1.7 channels and their sensitivity to a local anesthetic, lidocaine. Both IVs and lidocaine dose-response curves obtained from the injection-molded polymer device were in good agreement with data obtained from the commercial system.

  12. Excitation of voltage oscillations in an induction voltage adder

    Directory of Open Access Journals (Sweden)

    Nichelle Bruner

    2009-07-01

    Full Text Available The induction voltage adder is an accelerator architecture used in recent designs of pulsed-power driven x-ray radiographic systems such as Sandia National Laboratories’ Radiographic Integrated Test Stand (RITS, the Atomic Weapons Establishment’s planned Hydrus Facility, and the Naval Research Laboratory’s Mercury. Each of these designs relies on magnetic insulation to prevent electron loss across the anode-cathode gap in the vicinity of the adder as well as in the coaxial transmission line. Particle-in-cell simulations of the RITS adder and transmission line show that, as magnetic insulation is being established during a pulse, some electron loss occurs across the gap. Sufficient delay in the cavity pulse timings provides an opportunity for high-momentum electrons to deeply penetrate the cavities of the adder cells where they can excite radio-frequency resonances. These oscillations may be amplified in subsequent gaps, resulting in oscillations in the output power. The specific modes supported by the RITS-6 accelerator and details of the mechanism by which they are excited are presented in this paper.

  13. Record club

    CERN Multimedia

    Record club

    2010-01-01

      Bonjour a tous, Voici les 24 nouveaux DVD de Juillet disponibles depuis quelques jours, sans oublier les 5 CD Pop musique. Découvrez la saga du terroriste Carlos, la vie de Gainsbourg et les aventures de Lucky Luke; angoissez avec Paranormal Activity et évadez vous sur Pandora dans la peau d’Avatar. Toutes les nouveautés sont à découvrir directement au club. Pour en connaître la liste complète ainsi que le reste de la collection du Record Club, nous vous invitons sur notre site web: http://cern.ch/crc. Toutes les dernières nouveautés sont dans la rubrique « Discs of the Month ». Rappel : le club est ouvert les Lundis, Mercredis, Vendredis de 12h30 à 13h00 au restaurant n°2, bâtiment 504. A bientôt chers Record Clubbers.  

  14. Record Club

    CERN Multimedia

    Record Club

    2011-01-01

    http://cern.ch/Record.Club November  Selections Just in time for the holiday season, we have added a number of new CDs and DVDs into the Club. You will find the full lists at http://cern.ch/record.club; select the "Discs of the Month" button on the left side on the left panel of the web page and then Nov 2011. New films include the all 5 episodes of Fast and Furious, many of the most famous films starring Jean-Paul Belmondo and those of Louis de Funes and some more recent films such as The Lincoln Lawyer and, according to some critics, Woody Allen’s best film for years – Midnight in Paris. For the younger generation there is Cars 2 and Kung Fu Panda 2. New CDs include the latest releases by Adele, Coldplay and the Red Hot Chili Peppers. We have also added the new Duets II CD featuring Tony Bennett singing with some of today’s pop stars including Lady Gaga, Amy Winehouse and Willy Nelson. The Club is now open every Monday, Wednesday and Friday ...

  15. ATLAS Recordings

    CERN Multimedia

    Jeremy Herr; Homer A. Neal; Mitch McLachlan

    The University of Michigan Web Archives for the 2006 ATLAS Week Plenary Sessions, as well as the first of 2007, are now online. In addition, there are a wide variety of Software and Physics Tutorial sessions, recorded over the past couple years, to chose from. All ATLAS-specific archives are accessible here.Viewing requires a standard web browser with RealPlayer plug-in (included in most browsers automatically) and works on any major platform. Lectures can be viewed directly over the web or downloaded locally.In addition, you will find access to a variety of general tutorials and events via the portal. Shaping Collaboration 2006The Michigan group is happy to announce a complete set of recordings from the Shaping Collaboration conference held last December at the CICG in Geneva.The event hosted a mix of Collaborative Tool experts and LHC Users, and featured presentations by the CERN Deputy Director General, Prof. Jos Engelen, the President of Internet2, and chief developers from VRVS/EVO, WLAP, and other tools...

  16. Record Club

    CERN Multimedia

    Record Club

    2011-01-01

    http://cern.ch/Record.Club Nouveautés été 2011 Le club de location de CDs et de DVDs vient d’ajouter un grand nombre de disques pour l’été 2011. Parmi eux, Le Discours d’un Roi, oscar 2011 du meilleur film et Harry Potter les reliques de la mort (1re partie). Ce n’est pas moins de 48 DVDs et 10 CDs nouveaux qui vous sont proposés à la location. Il y en a pour tous les genres. Alors n’hésitez pas à consulter notre site http://cern.ch/record.club, voir Disc Catalogue, Discs of the month pour avoir la liste complète. Le club est ouvert tous les Lundi, Mercredi, Vendredi de 12h30 à 13h dans le bâtiment du restaurent N°2 (Cf. URL: http://www.cern.ch/map/building?bno=504) A très bientôt.  

  17. Record Club

    CERN Multimedia

    Record Club

    2011-01-01

    http://cern.ch/Record.Club June Selections We have put a significant number of new CDs and DVDs into the Club You will find the full lists at http://cern.ch/record.club and select the «Discs of the Month» button on the left side on the left panel of the web page and then June 2011. New films include the latest Action, Suspense and Science Fiction film hits, general drama movies including the Oscar-winning The King’s Speech, comedies including both chapter of Bridget Jones’s Diary, seven films for children and a musical. Other highlights include the latest Harry Potter release and some movies from the past you may have missed including the first in the Terminator series. New CDs include the latest releases by Michel Sardou, Mylene Farmer, Jennifer Lopez, Zucchero and Britney Spears. There is also a hits collection from NRJ. Don’t forget that the Club is now open every Monday, Wednesday and Friday lunchtimes from 12h30 to 13h00 in Restaurant 2, Building 504. (C...

  18. A Synchrophasor Based Optimal Voltage Control Scheme with Successive Voltage Stability Margin Improvement

    Directory of Open Access Journals (Sweden)

    Heng-Yi Su

    2016-01-01

    Full Text Available This paper proposes an optimal control scheme based on a synchronized phasor (synchrophasor for power system secondary voltage control. The framework covers voltage stability monitoring and control. Specifically, a voltage stability margin estimation algorithm is developed and built in the newly designed adaptive secondary voltage control (ASVC method to achieve more reliable and efficient voltage regulation in power systems. This new approach is applied to improve voltage profile across the entire power grid by an optimized plan for VAR (reactive power sources allocation; therefore, voltage stability margin of a power system can be increased to reduce the risk of voltage collapse. An extensive simulation study on the IEEE 30-bus test system is carried out to demonstrate the feasibility and effectiveness of the proposed scheme.

  19. Voltage biasing, cyclic voltammetry, & electrical impedance spectroscopy for neural interfaces.

    Science.gov (United States)

    Wilks, Seth J; Richner, Tom J; Brodnick, Sarah K; Kipke, Daryl R; Williams, Justin C; Otto, Kevin J

    2012-02-24

    Electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measure properties of the electrode-tissue interface without additional invasive procedures, and can be used to monitor electrode performance over the long term. EIS measures electrical impedance at multiple frequencies, and increases in impedance indicate increased glial scar formation around the device, while cyclic voltammetry measures the charge carrying capacity of the electrode, and indicates how charge is transferred at different voltage levels. As implanted electrodes age, EIS and CV data change, and electrode sites that previously recorded spiking neurons often exhibit significantly lower efficacy for neural recording. The application of a brief voltage pulse to implanted electrode arrays, known as rejuvenation, can bring back spiking activity on otherwise silent electrode sites for a period of time. Rejuvenation alters EIS and CV, and can be monitored by these complementary methods. Typically, EIS is measured daily as an indication of the tissue response at the electrode site. If spikes are absent in a channel that previously had spikes, then CV is used to determine the charge carrying capacity of the electrode site, and rejuvenation can be applied to improve the interface efficacy. CV and EIS are then repeated to check the changes at the electrode-tissue interface, and neural recordings are collected. The overall goal of rejuvenation is to extend the functional lifetime of implanted arrays.

  20. Insulation Resistance and Leakage Currents in Low-Voltage Ceramic Capacitors with Cracks

    Science.gov (United States)

    Teverovsky, Alexander A.

    2016-01-01

    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.

  1. Measurement and analysis of postsynaptic potentials using a novel voltage-deconvolution method.

    Science.gov (United States)

    Richardson, Magnus J E; Silberberg, Gilad

    2008-02-01

    Accurate measurement of postsynaptic potential amplitudes is a central requirement for the quantification of synaptic strength, dynamics of short-term and long-term plasticity, and vesicle-release statistics. However, the intracellular voltage is a filtered version of the underlying synaptic signal and so a method of accounting for the distortion caused by overlapping postsynaptic potentials must be used. Here a voltage-deconvolution technique is demonstrated that defilters the entire voltage trace to reveal an underlying signal of well-separated synaptic events. These isolated events can be cropped out and reconvolved to yield a set of isolated postsynaptic potentials from which voltage amplitudes may be measured directly-greatly simplifying this common task. The method also has the significant advantage of providing a higher temporal resolution of the dynamics of the underlying synaptic signal. The versatility of the method is demonstrated by a variety of experimental examples, including excitatory and inhibitory connections to neurons with passive membranes and those with activated voltage-gated currents. The deconvolved current-clamp voltage has many features in common with voltage-clamp current measurements. These similarities are analyzed using cable theory and a multicompartment cell reconstruction, as well as direct comparison to voltage-clamp experiments.

  2. Effects of. gamma. -ray irradiation on residual voltage in polyethylene containing antioxidant

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, Sanshiro; Fukuda, Tadashi; Sawa, Goro; Ieda, Masayuki

    1986-12-01

    For providing a non-destructive technique for determining the degree of deterioration in insulating material, an attempt is made to examine the effect of ..gamma..-ray irradiation on the residual voltage in low-density polyethylene containing an antioxidant. A phenol compound (Irganox 1010) or an amine compound (Antage F) is used as antioxidant. It is shown that for non-irradiated material, addition of Antage F increases both the residual voltage (V) and current (I) while the increase in V and I is less at Irganox 1010 concentrations up to about 5 percent. Irradiation of ..gamma..-rays has little influence on the properties of material containing a large concentration of an antioxidant, indicating that the addition of an antioxidant can increase resistance to radiation. Antioxidant has little effect, however, if its content is low. For a sample containing 5% Irganox 1010, an exposure of 41.5 Mrad increases the residual voltage but the increase is linear with time. For a sample containing 5% Antage F, on the other hand, the residual voltage is largely increased above an exposure of 7.3 Mrad, but the time dependence of residual voltage shows a maximum. Analysis is made of the discharge current from material containing a large content of an antioxidant, showing that addition of such an additive has favorable effects. Dependence of residual voltage on applied voltage is analyzed. Results obtained suggest that insulation deterioration due to ..gamma..-ray irradiation can be estimated from measurements of residual voltage. (Nogami, K.).

  3. Evaluation of the Voltage Support Strategies for the Low Voltage Grid Connected PV

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2010-01-01

    PVs. In order to increase PV penetration level further, new voltage support control functions for individual inverters are required. This paper investigates distributed reactive power regulation and active power curtailment strategies regarding the development of PV connection capacity by evaluation......Admissible range of grid voltage is one of the strictest constraints for the penetration of distributed photovoltaic (PV) generators especially connection to low voltage (LV) public networks. Voltage limits are usually fulfilled either by network reinforcements or limiting of power injections from...

  4. Low voltage transmission electron microscopy of graphene.

    Science.gov (United States)

    Bachmatiuk, Alicja; Zhao, Jiong; Gorantla, Sandeep Madhukar; Martinez, Ignacio Guillermo Gonzalez; Wiedermann, Jerzy; Lee, Changgu; Eckert, Juergen; Rummeli, Mark Hermann

    2015-02-04

    The initial isolation of graphene in 2004 spawned massive interest in this two-dimensional pure sp(2) carbon structure due to its incredible electrical, optical, mechanical, and thermal effects. This in turn led to the rapid development of various characterization tools for graphene. Examples include Raman spectroscopy and scanning tunneling microscopy. However, the one tool with the greatest prowess for characterizing and studying graphene is the transmission electron microscope. State-of-the-art (scanning) transmission electron microscopes enable one to image graphene with atomic resolution, and also to conduct various other characterizations simultaneously. The advent of aberration correctors was timely in that it allowed transmission electron microscopes to operate with reduced acceleration voltages, so that damage to graphene is avoided while still providing atomic resolution. In this comprehensive review, a brief introduction is provided to the technical aspects of transmission electron microscopes relevant to graphene. The reader is then introduced to different specimen preparation techniques for graphene. The different characterization approaches in both transmission electron microscopy and scanning transmission electron microscopy are then discussed, along with the different aspects of electron diffraction and electron energy loss spectroscopy. The use of graphene for other electron microscopy approaches such as in-situ investigations is also presented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  7. Multi-Stage Optimization Based Automatic Voltage Control Systems Considering Wind Power Forecasting Errors

    DEFF Research Database (Denmark)

    Qin, Nan; Bak, Claus Leth; Abildgaard, Hans

    2017-01-01

    cost and the generator reactive power output cost. The problem is formulated in a multi-stage optimal reactive power flow (MORPF) framework, solved by the nonlinear programming techniques via a rolling process. The voltage uncertainty caused by wind power forecasting errors is considered in the optimal......This paper proposes an automatic voltage control (AVC) system for power systems with limited continuous voltage control capability. The objective is to minimize the operational cost over a period, which consists of the power loss in the grid, the shunt switching cost, the transformer tap change...

  8. Modeling and Simulation of the Single Phase Voltage Source UPS Inverter With Fourth Order Output Filter

    Directory of Open Access Journals (Sweden)

    Javad Faiz

    2011-01-01

    Full Text Available A UPS inverter operates in wide load impedance ranges from resistive to capacitive or inductive load. At the same time, fast transient load response, good load regulation and good switching frequency suppression is required. The variation of the load impedance changes the filter transfer characteristic and thus the output voltage value. In this paper, an analysis and simulation of the single phase voltage source uninterruptible power supply (UPS with fourth order filter (multiple-filter in output inverter, based on the state space averaging and small signal linearization technique, is proposed. The simulation results show the high quality sinusoidal output voltage at different loads, with THD less than %5.

  9. VOLTAGE-DEPENDENT SODIUM AND POTASSIUM, BUT NO CALCIUM CONDUCTANCES IN DDT1 MF-2 SMOOTH-MUSCLE CELLS

    NARCIS (Netherlands)

    MOLLEMAN, A; NELEMANS, A; VANDENAKKER, J; DUIN, M; DENHERTOG, A

    1991-01-01

    Voltage-dependent inward and outward membrane currents were investigated in the DDT1 MF-2 smooth muscle cell line using the whole-cell patch-clamp technique. Application of a pulse protocol with subsequent depolarizing voltage steps elicited an inactivating inward current and a non-inactivating outw

  10. PROBLEMS OF ECONOMIC CRITERIA APPLICATION TO CALCULATION AND DESIGN OF HIGH-VOLTAGE PLASTIC-INSULATED POWER CABLES

    Directory of Open Access Journals (Sweden)

    O.V. Golik

    2013-09-01

    Full Text Available Results of cable transmitting capacity calculation for voltage of up to 220 kV are analyzed. The work is devoted to creation of a current rating calculation technique for high-voltage cross-linked polyethylene cables.

  11. Influence of current limitation on voltage stability with voltage sourced converter HVDC

    DEFF Research Database (Denmark)

    Zeni, Lorenzo; Jóhannsson, Hjörtur; Hansen, Anca Daniela;

    2013-01-01

    A first study of voltage stability with relevant amount of Voltage Sourced Converter based High Voltage Direct Current (VSC-HVDC) transmission is presented, with particular focus on the converters’ behaviour when reaching their rated current. The detrimental effect of entering the current...

  12. Voltage stability in low voltage microgrids in aspects of active and reactive power demand

    Directory of Open Access Journals (Sweden)

    Parol Mirosław

    2016-03-01

    Full Text Available Low voltage microgrids are autonomous subsystems, in which generation, storage and power and electrical energy consumption appear. In the paper the main attention has been paid to the voltage stability issue in low voltage microgrid for different variants of its operation. In the introduction a notion of microgrid has been presented, and also the issue of influence of active and reactive power balance on node voltage level has been described. Then description of voltage stability issue has been presented. The conditions of voltage stability and indicators used to determine voltage stability margin in the microgrid have been described. Description of the low voltage test microgrid, as well as research methodology along with definition of considered variants of its operation have been presented further. The results of exemplary calculations carried out for the daily changes in node load of the active and reactive power, i.e. the voltage and the voltage stability margin indexes in nodes have been presented. Furthermore, the changes of voltage stability margin indexes depending on the variant of the microgrid operation have been presented. Summary and formulation of conclusions related to the issue of voltage stability in microgrids have been included at the end of the paper.

  13. RECORD CLUB

    CERN Multimedia

    Record Club

    2010-01-01

    DVD James Bond – Series Complete To all Record Club Members, to start the new year, we have taken advantage of a special offer to add copies of all the James Bond movies to date, from the very first - Dr. No - to the latest - Quantum of Solace. No matter which of the successive 007s you prefer (Sean Connery, George Lazenby, Roger Moore, Timothy Dalton, Pierce Brosnan or Daniel Craig), they are all there. Or perhaps you have a favourite Bond Girl, or even perhaps a favourite villain. Take your pick. You can find the full selection listed on the club web site http://cern.ch/crc; use the panel on the left of the page “Discs of the Month” and select Jan 2010. We remind you that we are open on Mondays, Wednesdays and Fridays from 12:30 to 13:00 in Restaurant 2 (Bldg 504).

  14. Record breakers

    CERN Document Server

    Antonella Del Rosso

    2012-01-01

    In the sixties, CERN’s Fellows were but a handful of about 50 young experimentalists present on site to complete their training. Today, their number has increased to a record-breaking 500. They come from many different fields and are spread across CERN’s different activity areas.   “Diversifying the Fellowship programme has been the key theme in recent years,” comments James Purvis, Head of the Recruitment, Programmes and Monitoring group in the HR Department. “In particular, the 2005 five-yearly review introduced the notion of ‘senior’ and ‘junior’ Fellowships, broadening the target audience to include those with Bachelor-level qualifications.” Diversification made CERN’s Fellowship programme attractive to a wider audience but the number of Fellows on site could not have increased so much without the support of EU-funded projects, which were instrumental in the growth of the programme. ...

  15. Modeling and Simulation of Low Voltage Arcs

    NARCIS (Netherlands)

    Ghezzi, L.; Balestrero, A.

    2010-01-01

    Modeling and Simulation of Low Voltage Arcs is an attempt to improve the physical understanding, mathematical modeling and numerical simulation of the electric arcs that are found during current interruptions in low voltage circuit breakers. An empirical description is gained by refined electrical

  16. High-voltage engineering and testing

    CERN Document Server

    Ryan, Hugh M

    2013-01-01

    This 3rd edition of High Voltage Engineering Testing describes strategic developments in the field and reflects on how they can best be managed. All the key components of high voltage and distribution systems are covered including electric power networks, UHV and HV. Distribution systems including HVDC and power electronic systems are also considered.

  17. Modeling and Simulation of Low Voltage Arcs

    NARCIS (Netherlands)

    Ghezzi, L.; Balestrero, A.

    2010-01-01

    Modeling and Simulation of Low Voltage Arcs is an attempt to improve the physical understanding, mathematical modeling and numerical simulation of the electric arcs that are found during current interruptions in low voltage circuit breakers. An empirical description is gained by refined electrical m

  18. High Voltage Applications of Explosively Formed Fuses

    Science.gov (United States)

    Tasker, D. G.; Goforth, J. H.; Fowler, C. M.; Herrera, D. H.; King, J. C.; Lopez, E. A.; Martinez, E. C.; Oona, H.; Marsh, S. P.; Reinovsky, R. E.; Stokes, J.; Tabaka, L. J.; Torres, D. T.; Sena, F. C.; Kiuttu, G.; Degnan, J.

    2004-11-01

    At Los Alamos, we have primarily applied Explosively Formed Fuse (EFF) techniques to high current systems. In these systems, the EFF has interrupted currents from 19-25 MA, thus diverting the current to low inductance loads. The transferred current magnitude is determined by the ratio of storage inductance to load inductance and, with dynamic loads, the current has ranged from 12-20 MA. In a system with 18 MJ stored energy, the switch operates at a power of up to 6 TW. We are now investigating the use of the EFF technique to apply high voltages to high impedance loads in systems that are more compact. In these systems we are exploring circuits with EFF lengths from 43-100 cm, which have storage inductances large enough to apply 300-500 kV across high impedance loads. Experimental results and design considerations are presented. Using cylindrical EFF switches of 10 cm diameter and 43 cm length, currents of approximately 3 MA were interrupted producing ~200 kV. This indicates the switch had an effective resistance of ~100 mΩ where 150-200 mΩ was expected. To understand the lower performance, several parameters were studied including electrical conduction through the explosive products; current density; explosive initiation; insulator type and conductor thickness. The results show a number of interesting features, most notably that the primary mechanism of switch operation is mechanical and not electrical fusing of the conductor. Switches opening on a 1-10 μs time scale with resistances starting at 50 μΩ and increasing to perhaps 1 Ω now seem possible to construct using explosive charges as small as a few pounds.

  19. 3D virtual reconstruction of the choir of the Convent of Santa Clara in Toro (Zamora: recovering a medieval space of female devotion through photogrammetric recording and rendering techniques

    Directory of Open Access Journals (Sweden)

    Fernando Gutiérrez Baños

    2016-11-01

    Full Text Available The Convent of Santa Clara in Toro (Zamora was founded in the mid-13th century. After destruction during the Castilian civil struggles of the last years of this century, its fabric was rebuilt and it was inhabited again by the Clarissan nuns, who still occupy it.  Its architecture corresponds for the most part to its early-14th century rebuilding, even though it is concealed by works carried out from the 16th to the 18th centuries, so that it is apparently a Baroque complex.  In the 1950s, in the choir of this Medieval hidden structure, a set of wall paintings of the mid-14thcentury was brought to light (one of the most important set of wall paintings of the early Gothic period ever found in Castile, but they were immediately detached from the walls and sold. It was only after a combination of circumstances that they came back to Toro to be installed in another building, the church of San Sebastián de los Caballeros, transformed into a museum. As a consequence of all these operations, the arrangement and sense of these wall paintings was lost. The virtual three-dimensional (3D reconstruction, based on a deep analysis and criticism of historical sources and on a close inspection and photogrammetric recording of the original room once occupied by the wall paintings, enables us to place them back in their original context through the use of rendering techniques, so recovering one of the most exciting spaces of female devotion of the Castilian 14thcentury.

  20. Low Power Low Voltage Bulk Driven Balanced OTA

    Directory of Open Access Journals (Sweden)

    Neha Gupta

    2012-01-01

    Full Text Available The last few decades, a great deal of attention has been paid to low-voltage (LV low-power (LP integrated circuits design since the power consumption has become a critical issue. Among many techniques used for the design of LV LP analog circuits, the Bulk-driven principle offers a promising route towards this design for many aspects mainly the simplicity and using the conventional MOS technology to implement these designs. This paper is devoted to the Bulk-driven (BD principle and utilizing this principle to design LV LP building block of Operational Transconductance Amplifier (OTA in standard CMOS processes and supply voltage 0.9V. The simulation results have been carried out by the Spice simulatorusing the 130nm CMOS technology from TSMC.

  1. Low Power Low Voltage Bulk Driven Balanced OTA

    Directory of Open Access Journals (Sweden)

    Neha Gupta

    2011-12-01

    Full Text Available The last few decades, a great deal of attention has been paid to low-voltage (LV low-power (LP integrated circuits design since the power consumption has become a critical issue. Among many techniques used for the design of LV LP analog circuits, the Bulk-driven principle offers a promising route towards this design for many aspects mainly the simplicity and using the conventional MOS technology to implement these designs. This paper is devoted to the Bulk-driven (BD principle and utilizing this principle to design LV LP building block of Operational Trans conductance Amplifier (OTA in standard CMOS processes and supply voltage 0.9 V. The simulation results have been carried out by the Spice simulator using the 130 nm CMOS technology from TSMC.

  2. Low Power Low Voltage Bulk Driven Balanced OTA

    CERN Document Server

    Gupta, Neha; Suthar, Meenakshi; Soni, Priyanka

    2012-01-01

    The last few decades, a great deal of attention has been paid to low-voltage (LV) low-power (LP) integrated circuits design since the power consumption has become a critical issue. Among many techniques used for the design of LV LP analog circuits, the Bulk-driven principle offers a promising route towards this design for many aspects mainly the simplicity and using the conventional MOS technology to implement these designs. This paper is devoted to the Bulk-driven (BD) principle and utilizing this principle to design LV LP building block of Operational Transconductance Amplifier (OTA) in standard CMOS processes and supply voltage 0.9V. The simulation results have been carried out by the Spice simulator using the 130nm CMOS technology from TSMC.

  3. Low voltage n-type OFET based on double insulators

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jian-lin; ZHANG Fu-jia

    2008-01-01

    A top contact n-type organic field-effect transistor with low operating voltage was fabricated by employing Ta2O5/PMMA as the double insulators and PTCDI-Cl2 as the semiconductor active layer. The Ta2O5 layer was prepared by using simple economical anodization technique and the PMMA layer was prepared by using the spin-coating method. Compared with the OFET with single Ta2O5 insulator, the device with double insulators shows obviously better electrical performance. It has a field effect electron mobility of 0.063 cm2/Vs, an on/offratio of 1.7×104 and a threshold voltage of 2.3 V.

  4. Low Power/Low Voltage Interface Circuitry for Capacitive Sensors

    DEFF Research Database (Denmark)

    Furst, Claus Efdmann

    This thesis focuses mainly on low power/low voltage interface circuits, implemented in CMOS, for capacitive sensors. A brief discussion of demands and possibilities for analog signal processing in the future is presented. Techniques for low power design is presented. This is done by analyzing power...... consumption of different amplifier topologies. Next, low power features of different amplifier types are analyzed on transistor level. A brief comparison of SI circuits for low power applications vs. SC circuits is presented. Methodologies for low voltage design is presented. This is followed by a collection...... power consumption. It is shown that the Sigma-Delta modulator is advantageous when embedded in a feedback loop with a mechanical sensor. Here a micro mechanical capacitive microphone. Feedback and detection circuitry for a capacitive microphone is presented. Practical implementations of low power...

  5. Radiatively heated high voltage pyroelectric crystal pulser

    Energy Technology Data Exchange (ETDEWEB)

    Antolak, A.J., E-mail: antolak@sandia.gov [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)

    2014-01-21

    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.

  6. Non-contact current and voltage sensor

    Science.gov (United States)

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

    2014-03-25

    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.

  7. Coordinated Voltage Control of Active Distribution Network

    Directory of Open Access Journals (Sweden)

    Xie Jiang

    2016-01-01

    Full Text Available This paper presents a centralized coordinated voltage control method for active distribution network to solve off-limit problem of voltage after incorporation of distributed generation (DG. The proposed method consists of two parts, it coordinated primal-dual interior point method-based voltage regulation schemes of DG reactive powers and capacitors with centralized on-load tap changer (OLTC controlling method which utilizes system’s maximum and minimum voltages, to improve the qualified rate of voltage and reduce the operation numbers of OLTC. The proposed coordination has considered the cost of capacitors. The method is tested using a radial edited IEEE-33 nodes distribution network which is modelled using MATLAB.

  8. Hysteresis in voltage-gated channels.

    Science.gov (United States)

    Villalba-Galea, Carlos A

    2016-09-30

    Ion channels constitute a superfamily of membrane proteins found in all living creatures. Their activity allows fast translocation of ions across the plasma membrane down the ion's transmembrane electrochemical gradient, resulting in a difference in electrical potential across the plasma membrane, known as the membrane potential. A group within this superfamily, namely voltage-gated channels, displays activity that is sensitive to the membrane potential. The activity of voltage-gated channels is controlled by the membrane potential, while the membrane potential is changed by these channels' activity. This interplay produces variations in the membrane potential that have evolved into electrical signals in many organisms. These signals are essential for numerous biological processes, including neuronal activity, insulin release, muscle contraction, fertilization and many others. In recent years, the activity of the voltage-gated channels has been observed not to follow a simple relationship with the membrane potential. Instead, it has been shown that the activity of voltage-gated channel displays hysteresis. In fact, a growing number of evidence have demonstrated that the voltage dependence of channel activity is dynamically modulated by activity itself. In spite of the great impact that this property can have on electrical signaling, hysteresis in voltage-gated channels is often overlooked. Addressing this issue, this review provides examples of voltage-gated ion channels displaying hysteretic behavior. Further, this review will discuss how Dynamic Voltage Dependence in voltage-gated channels can have a physiological role in electrical signaling. Furthermore, this review will elaborate on the current thoughts on the mechanism underlying hysteresis in voltage-gated channels.

  9. Feasibility of Stochastic Voltage/VAr Optimization Considering Renewable Energy Resources for Smart Grid

    Science.gov (United States)

    Momoh, James A.; Salkuti, Surender Reddy

    2016-06-01

    This paper proposes a stochastic optimization technique for solving the Voltage/VAr control problem including the load demand and Renewable Energy Resources (RERs) variation. The RERs often take along some inputs like stochastic behavior. One of the important challenges i. e., Voltage/VAr control is a prime source for handling power system complexity and reliability, hence it is the fundamental requirement for all the utility companies. There is a need for the robust and efficient Voltage/VAr optimization technique to meet the peak demand and reduction of system losses. The voltages beyond the limit may damage costly sub-station devices and equipments at consumer end as well. Especially, the RERs introduces more disturbances and some of the RERs are not even capable enough to meet the VAr demand. Therefore, there is a strong need for the Voltage/VAr control in RERs environment. This paper aims at the development of optimal scheme for Voltage/VAr control involving RERs. In this paper, Latin Hypercube Sampling (LHS) method is used to cover full range of variables by maximally satisfying the marginal distribution. Here, backward scenario reduction technique is used to reduce the number of scenarios effectively and maximally retain the fitting accuracy of samples. The developed optimization scheme is tested on IEEE 24 bus Reliability Test System (RTS) considering the load demand and RERs variation.

  10. Design and development of digital seismic amplifier recorder

    Energy Technology Data Exchange (ETDEWEB)

    Samsidar, Siti Alaa; Afuar, Waldy; Handayani, Gunawan, E-mail: gunawanhandayani@gmail.com [Department of Physics, ITB (Indonesia)

    2015-04-16

    A digital seismic recording is a recording technique of seismic data in digital systems. This method is more convenient because it is more accurate than other methods of seismic recorders. To improve the quality of the results of seismic measurements, the signal needs to be amplified to obtain better subsurface images. The purpose of this study is to improve the accuracy of measurement by amplifying the input signal. We use seismic sensors/geophones with a frequency of 4.5 Hz. The signal is amplified by means of 12 units of non-inverting amplifier. The non-inverting amplifier using IC 741 with the resistor values 1KΩ and 1MΩ. The amplification results were 1,000 times. The results of signal amplification converted into digital by using the Analog Digital Converter (ADC). Quantitative analysis in this study was performed using the software Lab VIEW 8.6. The Lab VIEW 8.6 program was used to control the ADC. The results of qualitative analysis showed that the seismic conditioning can produce a large output, so that the data obtained is better than conventional data. This application can be used for geophysical methods that have low input voltage such as microtremor application.

  11. Design and development of digital seismic amplifier recorder

    Science.gov (United States)

    Samsidar, Siti Alaa; Afuar, Waldy; Handayani, Gunawan

    2015-04-01

    A digital seismic recording is a recording technique of seismic data in digital systems. This method is more convenient because it is more accurate than other methods of seismic recorders. To improve the quality of the results of seismic measurements, the signal needs to be amplified to obtain better subsurface images. The purpose of this study is to improve the accuracy of measurement by amplifying the input signal. We use seismic sensors/geophones with a frequency of 4.5 Hz. The signal is amplified by means of 12 units of non-inverting amplifier. The non-inverting amplifier using IC 741 with the resistor values 1KΩ and 1MΩ. The amplification results were 1,000 times. The results of signal amplification converted into digital by using the Analog Digital Converter (ADC). Quantitative analysis in this study was performed using the software Lab VIEW 8.6. The Lab VIEW 8.6 program was used to control the ADC. The results of qualitative analysis showed that the seismic conditioning can produce a large output, so that the data obtained is better than conventional data. This application can be used for geophysical methods that have low input voltage such as microtremor application.

  12. Research on Sectionalized Energy-Saving Control Strategy Based on Frequency and Voltage Regulator Technique for Induction Motor With Potential Loads%势能负载条件下感应电机变频-调压分段节能控制策略研究

    Institute of Scientific and Technical Information of China (English)

    赵海森; 王博; 王义龙; 李和明

    2015-01-01

    目前投入油田应用的节能设备大多基于单一节能技术,且通用性较差。该文结合抽油机负载特点及四连杆运动规律,提出一种基于变频器的变频调压分段协调运行的通用节能新技术。该技术通过在不同曲柄运行位置区间选择性地改变感应电机供电模式,使其运行状态发生改变,主要特征:1)采用变频手段控制悬点加速度大小,间接削弱悬点载荷中的惯性力矩成分,从而减小上冲程阶段电机消耗的电功率;2)实时监测电机实际负荷状况,采取跟踪调压技术确保电机运行效率最优。以一台Y2-280S、37kW感应电机及其驱动的 CYJ10型游梁式抽油机为算例,对多种复杂工况下的节电效果进行综合仿真对比。结果表明:该方法能够有效改善上冲程前半周期平衡块对负载的平衡作用,降低了最大载荷值;不同动液面、平衡配重下系统节电率大于12%,具有较强通用性;从而为油田节能开辟了新思路,具有重要理论意义和实用价值。%ABSTRACT:The current energy-saving devices used in oil field are mostly based on single energy-saving technology and with the poor universality. Combining with load characteristics of beam pump unit (BPU) and mechanical features of four-bar linkage, this paper presented a sectionalized control strategy of frequency and voltage regulator based on the converter. This technique makes induction motor operate in preset range selectively by changing the power supply mode in different crank position sectors, whose main features are as follows: 1) Controlling horse-head acceleration through frequency conversion and indirectly weakening the inertia component of polished rod load, thereby dropping the power consumption during the up-stroke; 2) According to real-time monitoring load conditions of motor, adopting the tracking regulator technique to optimize running efficiency. Taking a CYJ10 BPU driven by

  13. Phase-lock loop of Grid-connected Voltage Source Converter under non-ideal grid condition

    DEFF Research Database (Denmark)

    Wang, Haojie; Sun, Hai; Han, Minxiao;

    2015-01-01

    phase information cannot be accurately tracked. Based on analysis of the cause of double-frequency ripple when unbalance exists in main grid, a phase-locked loop (PLL) detection technique is proposed. Under the conditions of unsymmetrical system voltage, varying system frequency, single-phase system......It is a normal practice that the DC micro-grid is connected to AC main grid through Grid-connected Voltage Source Converter (G-VSC) for voltage support. Accurate control of DC micro-grid voltage is difficult for G-VSC under unbalanced grid condition as the fundamental positive-sequence component...

  14. Synchronous circadian voltage rhythms with asynchronous calcium rhythms in the suprachiasmatic nucleus.

    Science.gov (United States)

    Enoki, Ryosuke; Oda, Yoshiaki; Mieda, Michihiro; Ono, Daisuke; Honma, Sato; Honma, Ken-Ichi

    2017-03-07

    The suprachiasmatic nucleus (SCN), the master circadian clock, contains a network composed of multiple types of neurons which are thought to form a hierarchical and multioscillator system. The molecular clock machinery in SCN neurons drives membrane excitability and sends time cue signals to various brain regions and peripheral organs. However, how and at what time of the day these neurons transmit output signals remain largely unknown. Here, we successfully visualized circadian voltage rhythms optically for many days using a genetically encoded voltage sensor, ArcLightD. Unexpectedly, the voltage rhythms are synchronized across the entire SCN network of cultured slices, whereas simultaneously recorded Ca(2+) rhythms are topologically specific to the dorsal and ventral regions. We further found that the temporal order of these two rhythms is cell-type specific: The Ca(2+) rhythms phase-lead the voltage rhythms in AVP neurons but Ca(2+) and voltage rhythms are nearly in phase in VIP neurons. We confirmed that circadian firing rhythms are also synchronous and are coupled with the voltage rhythms. These results indicate that SCN networks with asynchronous Ca(2+) rhythms produce coherent voltage rhythms.

  15. Submodule Capacitance Voltage Balancing of Modular Multilevel Converter Based on Carrier Phase Shifted SPWM Technique%采用载波移相技术的模块化多电平换流器电容电压平衡控制

    Institute of Scientific and Technical Information of China (English)

    赵昕; 赵成勇; 李广凯; 饶宏; 黎小林

    2011-01-01

    Modular multilevel converter (MMC) was a new multilevel converter suitable for VSC-HVDC. The working principle of the submodules of MMC and converter topology were introduced in this paper. Considering the new topology and its application in the field of high voltage direct current transmission system, a novel carried phase shifted sinusoidal pulse width modulation(CPS-SPWM) scheme suitable for MMC was presented. Compared with other modulation schemes, the scheme proposed had superior dynamic regulation and excellent harmonic characteristics at lower switching frequency. Voltage balancing among the submodules was a crucial problem of MMC. Based on the equipartition of energy and voltage balance, a voltage-balancing scheme of submodules was presented in this paper with the topology of MMC and modulation. This scheme can effectively ensure each submodule at the same capacitance and voltage level. The correctness and effectiveness of the proposed schemes are verified by the simulation.%模块化多电半换流器(modularmultilevelconveer,MMC)是应用于电压源换流器直流输电(voltagesourceconverter-highvoltageDC,VSC.rrvoc)的新型多电平换流器拓扑。该文介绍了MMC的拓扑结构及相应的工作原理。针对该新型换流器拓扑的特点及其在高压直流输电领域中的应用,提出一种新颖的适用于模块化多电平换流器的载波移相调制策略(carrierphase.shiftedSPWM,CPS.SPWM)。与其他调制策略相比,该策略动态调节能力强,且使MMC在

  16. Record Club

    CERN Multimedia

    Record Club

    2012-01-01

      March  Selections By the time this appears, we will have added a number of new CDs and DVDs into the Club. You will find the full lists at http://cern.ch/record.club; select the "Discs of the Month" button on the left panel of the web page and then Mar 2012. New films include recent releases such as Johnny English 2, Bad Teacher, Cowboys vs Aliens, and Super 8. We are also starting to acquire some of the classic films we missed when we initiated the DVD section of the club, such as appeared in a recent Best 100 Films published by a leading UK magazine; this month we have added Spielberg’s Jaws and Scorsese’s Goodfellas. If you have your own ideas on what we are missing, let us know. For children we have no less than 8 Tin-Tin DVDs. And if you like fast moving pop music, try the Beyonce concert DVD. New CDs include the latest releases from Paul McCartney, Rihanna and Amy Winehouse. There is a best of Mylene Farmer, a compilation from the NRJ 201...

  17. Advanced patch-clamp techniques and single-channel analysis

    NARCIS (Netherlands)

    Biskup, B; Elzenga, JTM; Homann, U; Thiel, G; Wissing, F; Maathuis, FJM

    1999-01-01

    Much of our knowledge of ion-transport mechanisms in plant cell membranes comes from experiments using voltage-clamp. This technique allows the measurement of ionic currents across the membrane, whilst the voltage is held under experimental control. The patch-clamp technique was developed to study t

  18. PI and Fuzzy Control Strategies for High Voltage Output DC-DC Boost Power Converter - Hardware Implementation and Analysis

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Siano, Pierluigi

    2016-01-01

    converter with inbuilt voltage-lift technique and overcome the aforementioned deficiencies. Further, the control strategy is adapted based on proportional-integral (P-I) and fuzzy logic, closed-loop controller to regulate the outputs and ensure the performances. Complete hardware prototype of EHV converter......This paper presents the control strategies by Proportional-Integral (P-I) and Fuzzy Logic (FL) for a DC-DC boost power converter for high output voltage configuration. Standard DC-DC converters are traditionally used for high voltage direct current (HVDC) power transmission systems. But, lack its...... performances in terms of efficiency, reduced transfer gain and increased cost with sensor units. Moreover, the internal self-parasitic components reduce the output voltage and efficiency of classical high voltage converters (HVC). This investigation focused on extra high-voltage (EHV) DC-DC boost power...

  19. 低压脱扣器电压暂降敏感性试验研究%Experimental Research on Sensitivity of Low Voltage Releaser to Voltage Sag

    Institute of Scientific and Technical Information of China (English)

    欧阳森; 刘平; 吴彤彤; 杨家豪; 曾江

    2015-01-01

    Using test method the low voltage releaser is researched and its action area, no action area and fuzzy area under the composite actions of the amplitude, the duration and the phase of voltage sag are obtained. On the basis of researching Chinese National Standard GB/T17626.11—2008 in depth, the detailed analysis on related research materials home and abroad are carried out, and a test scheme for sensitivity of low voltage releaser to voltage sag is constructed. Based on this test scheme, twelve types of low voltage releasers, which belong to the mainstream in the present market, are taken as the specimens to bear different amplitudes, durations and phases of voltage sags, while the action situations of low voltage releasers are observed and recorded. On the same voltage amplitude-duration plane the voltage tolerance curves of these low voltage releasers under different phase are plotted to form the family of voltage tolerance curves and then the upper and lower envelopes of the curve family are drawn. Through synthesizing and lumping the envelops of voltage tolerance curves belonging to different types of low voltage releasers, the three-region action characteristics of low voltage releaser under voltage sag, namely the explicit action region, the explicit no action region and the fuzzy action region, which can provide data support for the optimized design and manufacture of low voltage releasers and offer theoretical foundation for economic evaluation of voltage sag, are formed.%采用试验方法对低压脱扣器进行研究,得出其在电压暂降幅值、持续时间、相位组合作用下的动作区域、不动作区域、模糊区域。在深入研究国标GB/T 17626.11—2008的基础上,详细分析国内外相关研究资料,构建了低压脱扣器电压暂降敏感性试验方案。基于试验方案,对目前市场上主流的12种型号低压脱扣器进行试验,使其承受不同电压暂降幅值、持续时间及相位,观察并

  20. Fuel Cell/Electrochemical Cell Voltage Monitor

    Science.gov (United States)

    Vasquez, Arturo

    2012-01-01

    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.

  1. CERN News: Selection of the type of superconducting coil for the Omega project; New intensity records at the proton synchrotron; Progress with the Spiral Reader film measuring equipment; New technique at transition energy on the proton synchrotron; CERN Courier 10th anniversary; Equipment travelling from and to Serpukhov

    CERN Multimedia

    1969-01-01

    CERN News: Selection of the type of superconducting coil for the Omega project; New intensity records at the proton synchrotron; Progress with the Spiral Reader film measuring equipment; New technique at transition energy on the proton synchrotron; CERN Courier 10th anniversary; Equipment travelling from and to Serpukhov

  2. High voltage electricity installations a planning perspective

    CERN Document Server

    Jay, Stephen Andrew

    2006-01-01

    The presence of high voltage power lines has provoked widespread concern for many years. High Voltage Electricity Installations presents an in-depth study of policy surrounding the planning of high voltage installations, discussing the manner in which they are percieved by the public, and the associated environmental issues. An analysis of these concerns, along with the geographical, environmental and political influences that shape their expression, is presented. Investigates local planning policy in an area of the energy sector that is of highly topical environmental and public concern Cover

  3. Piezoelectric Voltage Coupled Reentrant Cavity Resonator

    CERN Document Server

    Carvalho, Natalia C; Floch, Jean-Michel Le; Tobar, Michael Edmund

    2014-01-01

    A piezoelectric voltage coupled microwave reentrant cavity has been developed. The central cavity post is bonded to a piezoelectric actuator allowing the voltage control of small post displacements over a high dynamic range. We show that such a cavity can be implemented as a voltage tunable resonator, a transducer for exciting and measuring mechanical modes of the structure and a transducer for measuring comparative sensitivity of the piezoelectric material. Experiments were conducted at room and cryogenic temperatures with results verified using Finite Element software.

  4. Voltage controlled spintronics device for logic applications.

    Energy Technology Data Exchange (ETDEWEB)

    Bader, S. D.; You, C.-Y.

    1999-09-03

    We consider logic device concepts based on our previously proposed spintronics device element whose magnetization orientation is controlled by application of a bias voltage instead of a magnetic field. The basic building block is the voltage-controlled rotation (VCR) element that consists of a four-layer structure--two ferromagnetic layers separated by both nanometer-thick insulator and metallic spacer layers. The interlayer exchange coupling between the two ferromagnetic layers oscillates as a function of applied voltage. We illustrate transistor-like concepts and re-programmable logic gates based on VCR elements.

  5. Selective Dirac voltage engineering of individual graphene field-effect transistors for digital inverter and frequency multiplier integrations

    Science.gov (United States)

    Sul, Onejae; Kim, Kyumin; Jung, Yungwoo; Choi, Eunsuk; Lee, Seung-Beck

    2017-09-01

    The ambipolar band structure of graphene presents unique opportunities for novel electronic device applications. A cycle of gate voltage sweep in a conventional graphene transistor produces a frequency-doubled output current. To increase the frequency further, we used various graphene doping control techniques to produce Dirac voltage engineered graphene channels. The various surface treatments and substrate conditions produced differently doped graphene channels that were integrated on a single substrate and multiple Dirac voltages were observed by applying a single gate voltage sweep. We applied the Dirac voltage engineering techniques to graphene field-effect transistors on a single chip for the fabrication of a frequency multiplier and a logic inverter demonstrating analog and digital circuit application possibilities.

  6. Modulation of major voltage- and ligand-gated ion channels in cultured neurons of the rat inferior colliculus by lidocaine

    Institute of Scientific and Technical Information of China (English)

    Mu YU; Lin CHEN

    2008-01-01

    Aim: The purpose of the present study was to explore how lidocaine as a thera-peutic drug for tinnitus targets voltage- and ligand-gated ion channels and changes the excitability of central auditory neurons. Methods: Membrane cur-rents mediated by major voltage- and ligand-gated channels were recorded from primary cultured neurons of the inferior colliculus (IC) in rats with whole-cell patch-clamp techniques in the presence and absence of lidocaine. The effects of lidocaine on the current-evoked firing of action potentials were also exam-ined. Results: Lidocaine at 100 μmol/L significantly suppressed voltage-gated sodium currents, transient outward potassium currents, and the glycine-induced chloride currents to 87.66%±2.12%, 96.33%±0.35%, and 91.46%±2.69% of that of the control level, respectively. At 1 mmol/L, lidocaine further suppressed the 3 currents to 70.26%±4.69%, 62.80% ±2.61%, and 89.11%±3.17% of that of the control level, respectively, However, lidocaine at concentrations lower than 1 mmol/L did not significantly affect GABA- or aspartate-induced currents. At a higher concentration (3 retool/L), lidocaine slightly depressed the GABA-in-duced current to 87.70%±1.87% of that of the control level. Finally, lidocaine at 100 μmol/L was shown to significantly suppress the current-evoked firing of IC neurons to 58.62%±11.22% of that of the control level, indicating that lidocaine decreases neuronal excitability. Conclusion: Although the action of lidocaine on the ion channels and receptors is complex and non-specific, it has an overall inhibitory effect on IC neurons at a clinically-relevant concentration, suggesting a central mechanism for lidocaine to suppress tinnitus.

  7. The Preceding Voltage Pulse and Separation Welding Mechanism of Electrical Contacts

    DEFF Research Database (Denmark)

    Yang, Xiao Cheng; Huang, Jiang; Li, Zhen Biao

    2016-01-01

    In order to obtain a better understanding of the welding mechanism in contact separation, electrical endurance tests were conducted with AgSnO2 and AgNi contacts on a simulation test device. Waveforms of contact displacement, contact voltage, and current were recorded with LabVIEW during the tests...

  8. A 2-D Analytical Threshold Voltage Model for Symmetric Double Gate MOSFET's Using Green’s Function

    Directory of Open Access Journals (Sweden)

    Anoop Garg

    2011-01-01

    Full Text Available We propose a new two dimensional (2D analytical solution of Threshold Voltage for undoped (or lightly doped Double Gate MOSFETs. We have used Green’s function technique to solve the 2D Poisson equation, and derived the threshold voltage model using minimum surface potential concept. This model is assumed uniform doping profile in Si region. The proposed model compared with existing literature and experimental data and we obtain excellent agreements with previous techniques.

  9. Programmable high voltage power supply with regulation confined to the high voltage section

    Science.gov (United States)

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

    1994-01-01

    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.

  10. Transformerless DC-DC Converter Using Cockcroft-Walton Voltage Multiplier to Obtain High DC Voltage

    Directory of Open Access Journals (Sweden)

    Meghana G Naik,

    2014-11-01

    Full Text Available In the present scenario the use of transformer for high voltages in converter circuit reduces the overall operating efficiency due to leakage inductance and use of transformer also increases the operational cost. . Therefore the proposed system is implemented with transformer less DC-DC converter so as to obtain high DC voltage with the use of nine stage Cockcroft-Walton (CW voltage multiplier. The proposed converter operates in CCM (continuous conduction mode, so that the converter switch stress, the switching losses are reduced. The DC voltage at the input of the proposed model is low and is boosted up by boost inductor (Ls in DC-DC converter stage and performs inverter operation. The number of stages in CW-voltage multiplier circuit is applied with low input pulsating DC (AC Voltage voltage where it is getting converted to high DC output voltage. The proposed converter switches operates at two independent frequencies, modulating (fsm andalternating (fsc frequency. The fsm operates at higher frequency of the output while the fsc operates at lower frequency of the desired output voltage ripple and the output ripples can be adjusted by the switch Sc1 and Sc2. The regulation of the output voltage is achieved by controlling the Duty ratio.The simulation is carried over by the MATLABSIMULINK.

  11. Effects of acidic pH on voltage-gated ion channels in rat trigeminal mesencephalic nucleus neurons.

    Science.gov (United States)

    Han, Jin-Eon; Cho, Jin-Hwa; Choi, In-Sun; Kim, Do-Yeon; Jang, Il-Sung

    2017-03-01

    The effects of acidic pH on several voltage-dependent ion channels, such as voltage-dependent K(+) and Ca(2+) channels, and hyperpolarization-gated and cyclic nucleotide-activated cation (HCN) channels, were examined using a whole-cell patch clamp technique on mechanically isolated rat mesencephalic trigeminal nucleus neurons. The application of a pH 6.5 solution had no effect on the peak amplitude of voltage-dependent K(+) currents. A pH 6.0 solution slightly, but significantly inhibited the peak amplitude of voltage-dependent K(+) currents. The pH 6.0 also shifted both the current-voltage and conductance-voltage relationships to the depolarization range. The application of a pH 6.5 solution scarcely affected the peak amplitude of membrane currents mediated by HCN channels, which were profoundly inhibited by the general HCN channel blocker Cs(+) (1 mM). However, the pH 6.0 solution slightly, but significantly inhibited the peak amplitude of HCN-mediated currents. Although the pH 6.0 solution showed complex modulation of the current-voltage and conductance-voltage relationships, the midpoint voltages for the activation of HCN channels were not changed by acidic pH. On the other hand, voltage-dependent Ca(2+) channels were significantly inhibited by an acidic pH. The application of an acidic pH solution significantly shifted the current-voltage and conductance-voltage relationships to the depolarization range. The modulation of several voltage-dependent ion channels by an acidic pH might affect the excitability of mesencephalic trigeminal nucleus neurons, and thus physiological functions mediated by the mesencephalic trigeminal nucleus could be affected in acidic pH conditions.

  12. A new Zero-Voltage-Transition PWM switching cell

    Energy Technology Data Exchange (ETDEWEB)

    Grigore, V. [Electronics and Telecommunications Faculty `Politebuica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

    1997-12-31

    In this paper a new Zero-Voltage-Transition (ZVT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus an auxiliary circuit (consisting of one active switch and some reactive components). The auxiliary circuit is inactive during the ON and OFF intervals of the switches in the normal PWM switch. However, the transitions between the two states are controlled by the auxiliary circuit. Prior to turn-on, the voltage across the active switch in the PWM cell is forced to zero, thus the turn-on losses of the active switch are practically eliminated. At turn-off the auxiliary circuit behaves like a non-dissipative passive snubber reducing the turn-off losses to a great extent. Zero-Voltage-Transition switching technique almost eliminates switching losses. The active switch operates under ZVT conditions, the passive switch (diode) has a controlled reverse recovery, and the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 6 refs.

  13. Design of low-voltage bipolar operational amplifiers

    Science.gov (United States)

    Fonderie, Jeroen

    The design of input stages for low voltage Operational Amplifiers (OpAmps) is considered. The purpose of this design emanates from the objective of having a common mode input voltage range that reaches from one supply rail to the other, and designs that have this feature both at a 2 V and at a 1 V supply are discussed. Possible output stage configurations are analyzed. This discussion is restricted to output stages that have an output voltage range that also reaches from rail to rail. Further, the output stage should be able to supply a sufficiently large output current to the load that is externally connected to the OpAmp. The frequency response of the output stage is the focus of the discussion. The circuit parts that remain to complete the design of the OpAmp are discussed. These circuit parts are the intermediate stage, inserted between the input and output stage to boost the overall gain of the OpAmp, some implementations of the class AB current control circuit, circuitry to protect the output transistor from heavy saturation and from excessive power consumption, and, finally, the proportional to absolute temperature reference current generator. A detailed analysis of the frequency compensation techniques that can be used to stabilize the OpAmp is given. From this theory, design criteria to successfully implement the compensation method are derived. The experimental OpAmp designs and the measurements performed on these designs are described. Conclusions and suggestions for further research are given.

  14. Technical feasibility study of Voltage Optimization Unit

    DEFF Research Database (Denmark)

    Hu, Junjie; Marinelli, Mattia; Coppo, Massimiliano

    transformer with OLTC per phase is necessary and valuable. The main conclusion is that power distribution transformer with OLTC control on each phase can significantly improve the PV hosting capacity in the analyzed unbal-anced scenarios. To investigate the verification problem, a simulation study...... is performed using the soft-wares DigSilent PowerFactory and Matlab. In this simulation study, a real low voltage network from Dong Eldistribution is modeled in Powerfactory. The measured data of the real low voltage network is analyzed and the resulting loading profiles including active and reactive power...... are used as load basics for the analysis. In term of PV genera-tion profiles, a realistic PV output power is assumed. Four relevant indicies such as phase neutral voltage, netural potential voltage, unbalanced factor (VUF), and power losses are evaluated in the present study. The simulation tests include...

  15. Can undersea voltage measurements detect tsunamis?

    Digital Repository Service at National Institute of Oceanography (India)

    Manoj, C.; Kuvshinov, A.; Neetu, S.; Harinarayana, T.

    The movement of electrically conducting ocean water in the ambient geomagnetic field induces secondary electric and magnetic fields in the oceans. Ocean water transport is now routinely inferred from undersea cable voltage data. We try to answer...

  16. Low voltage arc formation in railguns

    Science.gov (United States)

    Hawke, Ronald S.

    1987-01-01

    A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

  17. Induced voltage in an open wire

    CERN Document Server

    Morawetz, K; Trupp, A

    2015-01-01

    A puzzle arising from Faraday's law is considered and solved concerning the question which voltage is induced in an open wire feeling a time-varying homogeneous magnetic field. The longitudinal electric field contributes 1/3 and the transverse field 2/3 to the induced voltage. The representation of a homogeneous and time-varying magnetic field implies unavoidably a certain symmetry point or line dependent on the geometry of the source. As a consequence the induced voltage of an open wire is found to be the area covered with respect to the symmetry line or point perpendicular to the magnetic field. This in turn allows to find the symmetry points of a magnetic field source by measuring the voltage of an open wire. We present two exactly solvable models for a symmetry point and for a symmetry line. The results are applicable to open circuit problems and for astrophysical applications.

  18. Combined Digital Electronic Current and Voltage Transducer

    Institute of Scientific and Technical Information of China (English)

    段雄英; 邹积岩; 等

    2002-01-01

    A high-performance current and voltage measurement system has been developed in power system.The system is composed of two parts:one current measurement element and one voltage measurement element.A Rogowski coil and a capacitive voltage divider are used respectively for the line current and voltage measurements.Active electronic components are used to modulate signal,and power supply for these components is drawn from power line via an auxiliary current transformer,Measurement signal is transmitted y optical fibers,which is resistant to electromagnetic induction and noise,With careful design and the use of digital signal processing technology,the whole system can meet 0.5% accuracy for metering and provides large dynamic range coupled with good accuracy for protective relaying use.

  19. Compact, Lightweight, High Voltage Propellant Isolators Project

    Data.gov (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...

  20. Compact, Lightweight, High Voltage Propellant Isolators Project

    Data.gov (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...